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An assessment of the potential for biological phosphorus removal in Canadian wastewater treatment plants Morrison, Kirk Murray 1988

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AN ASSESSMENT OF THE POTENTIAL FOR BIOLOGICAL PHOSPHORUS REMOVAL IN CANADIAN WASTEWATER TREATMENT PLANTS by KIRK MURRAY MORRISON BASc, THE UNIVERSITY OF WATERLOO, 1982 THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF APPLIED SCIENCE i n THE FACULTY OF GRADUATE STUDIES (Department of C i v i l E n g i n e e r i n g ) We accept t h i s t h e s i s as conforming to the r e q u i r e d standard THE UNIVERSITY OF BRITISH COLUMBIA OCTOBER, 1988 ® K i r k Murray M o r r i s o n In presenting this thesis in partial fulfilment of the requirements for an advanced degree at the University of British Columbia, I agree that the Library shall make it freely available for reference and study. I further agree that permission for extensive copying of this thesis for scholarly purposes may be granted by the head of my department or by his or her representatives. It is understood that copying or publication of this thesis for financial gain shall not be allowed without my written permission. Department of C i v i l E n g i n e e r i n g The University of British Columbia Vancouver, Canada Date 88-10-12 .  DE-6 (2/88) ( i i ) ABSTRACT T h i s t h e s i s assesses the p o t e n t i a l f o r enhanced b i o l o g i c a l phosphorus (Bio-P) removal i n Canadian wastewater treatment p l a n t s . R e t r o f i t d e s i gns i n c o r p o r a t i n g Bio-P removal were prepared f o r nine wastewater treatment p l a n t s a c r o s s Canada, and were compared a g a i n s t chemical phosphorus removal t e c h n o l o g i e s . Incremental c a p i t a l and o p e r a t i n g c o s t s were c a l c u l a t e d and i n t e r n a l r a t e s of r e t u r n (IRR's) f o r the c a p i t a l investment r e q u i r e d t o i n s t a l l the Bio-P removal f a c i l i t i e s were c a l c u l a t e d . Based on these r e s u l t s , an assessment of the p o t e n t i a l use f o r the t e c h n o l o g y i n Canada i s made. Of the nine p l a n t s s t u d i e d , r e s u l t s i n d i c a t e t h a t Bio-P removal i s e c o n o m i c a l l y s u p e r i o r t o chemical phosphorus removal f o r the C a l g a r y Bonnybrook, Edmonton Gold Bar, Saskatoon Mclvor Weir and Regina wastewater treatment p l a n t s . In g e n e r a l , Bio-P removal appears to o f f e r s i g n i f i c a n t economic advantages to p l a n t s l o c a t e d i n A l b e r t a and Saskatchewan because of the h i g h c o s t o f phosphorus removal c h e m i c a l s i n these p r o v i n c e s . The p r e s e n t low c o s t of phosphorus removal chemicals i n O n t a r i o and Quebec l i k e l y l i m i t s the v i a b i l i t y of Bio-P removal to l a r g e 3 ( g r e a t e r than 300,000 m / d ) , s u i t a b l y c o n f i g u r e d p l a n t s . In B r i t i s h Columbia, where Bio-P removal i s p r e s e n t l y used i n the ( i i i ) Okanagan V a l l e y , the absence of widespread p r o v i n c i a l phosphorus removal standards makes f u t u r e Bio-P i n s t a l l a t i o n s u n l i k e l y . The p o t e n t i a l f o r Bio-P removal i n Manitoba, the Maritimes and the Yukon and Northwest T e r r i t o r i e s i s again l i m i t e d by the absence of phosphorus removal standards i n these p a r t s of Canada. R e s u l t s a l s o i n d i c a t e t h a t the use of an a n o x i c / a n a e r o b i c / a e r o b i c p r o c e s s i n the b i o r e a c t o r , i n c o n j u n c t i o n w i t h primary sludge f e r m e n t a t i o n through g r a v i t y t h i c k e n i n g , i s very a p p l i c a b l e to Canadian p l a n t s and o f f e r s p o t e n t i a l c a p i t a l and o p e r a t i n g c o s t s a v i n g s r e l a t i v e to other Bio-P p r o c e s s e s . The common p r a c t i c e of anaerobic sludge d i g e s t i o n , combined wi t h sludge dewatering and l a n d a p p l i c a t i o n , was found to be unfavourable from a Bio-P p e r s p e c t i v e u n l e s s the r e s u l t i n g s u p e r n a t a n t / f i l t r a t e streams can be re-used or d i s p o s e d of o u t s i d e of the mainstream treatment p r o c e s s . Through the p r e p a r a t i o n of the r e t r o f i t d esigns, i t was determined t h a t c e r t a i n aspects of Bio-P technology r e q u i r e a d d i t i o n a l r e s e a r c h i n order to o p t i m i z e treatment p l a n t d e s i g n . These i n c l u d e k i n e t i c m o d e l l i n g ; s h o r t SRT Bio-P removal; the a n o x i c / a n a e r o b i c / a e r o b i c p r o c e s s ; the use of g r a v i t y t h i c k e n i n g f o r primary sludge fermentation; and phosphorus r e l e a s e d u r i n g anaerobic d i g e s t i o n . ( i v ) TABLE OF CONTENTS PAGE NO. ABSTRACT ( i ) LIST OF TABLES ( v i i ) LIST OF FIGURES ( i x ) ACKNOWLEDGEMENT ( x i ) 1.0 INTRODUCTION 1 2.0 BACKGROUND TO STUDY 9 2.1 B i o c h e m i s t r y o f B i o l o g i c a l 9 Phosphorus Removal 2.2 Process Development 15 2.2.1 Mainstream Processes 16 2.2.2 Sidestream Processes 24 2.2.3 K i n e t i c M o d e l l i n g 27 2.3 Previ o u s Assessments o f Bio-P 31 Technology 2.3.1 T e c h n i c a l Assessments 31 , 2.3.2 Economic Assessments 35 3.0 STUDY METHODOLOGY 42 3.1 General 42 3.2 P l a n t S e l e c t i o n B a s i s 45 3.3 P l a n t Design B a s i s 51 3.3.1 G r i t Removal 53 3.3.2 Primary C l a r i f i e r s 53 3.3.3 Primary Sludge Fermentation 54 3.3.4 B i o r e a c t o r 66 3.3.5 Secondary C l a r i f i e r s 82 3.3.6 WAS T h i c k e n i n g 84 3.3.7 Sludge S t a b i l i z a t i o n 85 3.3.8 Sludge Dewatering 89 3.3.9 E f f l u e n t F i l t r a t i o n 90 3.3.10 Chemical Treatment 92 3.3.11 Op e r a t i o n s Requirements 98 3.3.12 M i s c e l l a n e o u s 101 3.4 Cost E s t i m a t i n g B a s i s 102 3.4.1 C a p i t a l C o s t s 102 3.4.2 O p e r a t i n g C o s t s 111 3.5 Economic A n a l y s i s B a s i s 114 4.0 RESULTS 117 4.1 C a l g a r y Bonnybrook Wastewater 117 Treatment P l a n t 4.1.1 P l a n t D e s c r i p t i o n 117 4.1.2 R e t r o f i t M o d i f i c a t i o n s 124 4.1.3 Cost A n a l y s i s 133 (v) PAGE NO. 4.2 Edmonton Gold Bar Wastewater 138 Treatment P l a n t 4.2.1 P l a n t D e s c r i p t i o n 138 4.2.2 R e t r o f i t M o d i f i c a t i o n s 144 4.2.3 Cost A n a l y s i s 156 4.3 Regina Sewage Treatment P l a n t 159 4.3.1 P l a n t D e s c r i p t i o n 159 4.3.2 R e t r o f i t M o d i f i c a t i o n s 163 4.3.3 Cost A n a l y s i s 173 4.4 Saskatoon H. Mclvor Weir Water 178 P o l l u t i o n C o n t r o l P l a n t 4.4.1 P l a n t D e s c r i p t i o n 178 4.4.2 R e t r o f i t M o d i f i c a t i o n s 182 4.4.3 Cost A n a l y s i s 190 4.5 Windsor L i t t l e R i v e r P o l l u t i o n 193 C o n t r o l P l a n t 4.5.1 P l a n t D e s c r i p t i o n 193 4.5.2 R e t r o f i t M o d i f i c a t i o n s 200 4.5.3 Cost A n a l y s i s 208 4.6 Grimsby Baker Road P o l l u t i o n 213 C o n t r o l P l a n t 4.6.1 P l a n t D e s c r i p t i o n 213 4.6.2 R e t r o f i t M o d i f i c a t i o n s 218 4.6.3 Cost A n a l y s i s 228 4.7 M i l t o n Water P o l l u t i o n C o n t r o l P l a n t . 232 4.7.1 P l a n t D e s c r i p t i o n 232 4.7.2 R e t r o f i t M o d i f i c a t i o n s 237 4.7.3 Cost A n a l y s i s 245 4.8 E l m i r a Water P o l l u t i o n C o n t r o l P l a n t 249 4.8.1 P l a n t D e s c r i p t i o n 249 4.8.2 R e t r o f i t M o d i f i c a t i o n s 254 4.8.3 Cost A n a l y s i s 263 4.9 W e l l e s l e y Water P o l l u t i o n C o n t r o l P l a n t 263 4.9.1 P l a n t D e s c r i p t i o n 263 4.9.2 R e t r o f i t M o d i f i c a t i o n s 267 4.9.3 Cost A n a l y s i s 271 5.0 DISCUSSION 275 5.1 General Review of R e s u l t s 275 5.2 Chemical Cost and A v a i l a b i l i t y 279 5.3 Sewage C h a r a c t e r i s t i c s 283 5.4 P l a n t S i z e and C o n f i g u r a t i o n 287 5.5 Sludge P r o c e s s i n g 290 5.6 N u t r i e n t Removal Standards 291 5.7 New Versus R e t r o f i t F a c i l i t i e s 293 5.8 O v e r a l l Assessment 294 5.9 Future Research Needs 299 6.0 CONCLUSIONS AND RECOMMENDATIONS 303 6.1 Con c l u s i o n s 303 6.2 Recommendations 305 ( v i ) PAGE NO. REFERENCES 307 APPENDICES A. L i s t of Symbols and A b b r e v i a t i o n s 316 B. B i o l o g i c a l N i t r o g e n Removal Overview 318 C. C a p i t a l Cost E s t i m a t i n g Support Data 321 ( v i i ) LIST OF TABLES PAGE NO. NO. TITLE 2.1 T y p i c a l O p e r a t i n g C o n d i t i o n s f o r Bio-P 20 Processes 2.2 Summary of Performance Assessments of 33 Bio-P Processes 2.3 Sewage C h a r a c t e r i s t i c s Required f o r Bio-P 34 Removal t o Less than 1.0 mg/L 2.4 Summary of USEPA Sponsored Study on Bio-P 37 Removal Economics 2.5 P h o s t r i p II Savings and Costs 40 3.1 Wastewater Treatment P l a n t s S t u d i e d 48 3.2 M a t e r i a l Take-Off S p e c i f i c a t i o n s 104 3.3 Extent of C a p i t a l Cost F a c t o r i n g 109 3.4 Chemical Cost Summary 113 4.1 C a l g a r y Bonnybrook O p e r a t i o n s Comparison 134 4.2 C a l g a r y Bonnybrook C a p i t a l Cost Summary 136 4.3 C a l g a r y Bonnybrook O p e r a t i n g Cost Summary 137 4.4 Edmonton Gold Bar Process Option 150 Economic Summary 4.5 Edmonton Gold Bar O p e r a t i o n s Comparison 155 4.6 Edmonton Gold Bar C a p i t a l Cost Summary 157 4.7 Edmonton Gold Bar O p e r a t i n g Cost Summary 158 4.8 Regina Operations Comparison 174 4.9 Regina C a p i t a l Cost Summary 175 4.10 Regina O p e r a t i n g Cost Summary 177 4.11 Saskatoon O p e r a t i o n s Comparison 189 4.12 Saskatoon C a p i t a l Cost Summary 191 4.13 Saskatoon O p e r a t i n g Cost Summary 192 ( v i i i ) PAGE NO. NO. TITLE 4.14 Windsor O p e r a t i o n s Comparison 209 4.15 Windsor C a p i t a l Cost Summary 210 ( E x i s t i n g F a c i l i t y ) 4.16 Windsor C a p i t a l Cost Summary 211 (New F a c i l i t y ) 4.17 Windsor O p e r a t i n g Cost Summary 212 4.18 Grimsby O p e r a t i o n s Comparison 229 4.19 Grimsby C a p i t a l Cost Summary 230 4.20 Grimsby O p e r a t i n g Cost Summary 231 4.21 M i l t o n O p e r a t i o n s Comparison 246 4.22 M i l t o n C a p i t a l Cost Summary 247 4.23 M i l t o n O p e r a t i n g Cost Summary 248 4.24 E l m i r a O p e r a t i o n s Comparison 260 4.25 E l m i r a C a p i t a l Cost Summary 261 4.26 E l m i r a O p e r a t i n g Cost Summary 262 4.27 W e l l e s l e y O p e r a t i o n s Comparison 270 4.28 W e l l e s l e y C a p i t a l Cost Summary 272 4.29 W e l l e s l e y O p e r a t i n g Cost Summary 273 5.1 Bio-P Economic Summary f o r P l a n t s S t u d i e d 276 5.2 Summary o f Alum Cos t s Required f o r a 280 Four P e r c e n t IRR 5.3 Summary of Iro n C o s t s Required f o r a 281 Four P e r c e n t IRR 5.4 Summary of I n f l u e n t Sewage C h a r a c t e r i s t i c s 285 5.5 C a p i t a l and Chemical Costs A s s o c i a t e d w i t h 292 Lime Treatment of D i g e s t o r Supernatant ( i x ) LIST OF FIGURES PAGE NO. NO. TITLE 2.1 S i m p l i f i e d Mechanism f o r B i o l o g i c a l 13 Phosphorus Removal 2.2 Mainstream Bio-P Process Schematics 17 2.3 Sidestream Bio-P Process Schematics 25 3.1 Primary Sludge Fermentation Process Options 59 3.2 Primary Sludge Fermenter Process 63 Flow Diagram 3.3 Automatic DO C o n t r o l Schematic 69 3.4 ORP M o n i t o r i n g Schematic f o r UCT Process 70 3.5 Lime Treatment Process Schematic 94 4.1 C a l g a r y Bonnybrook P l a n t Flowsheet ( E x i s t i n g ) 119 4.2 C a l g a r y Bonnybrook P l a n t Layout ( E x i s t i n g ) 120 4.3 C a l g a r y Bonnybrook R e t r o f i t Flowsheet 125 4.4 C a l g a r y Bonnybrook R e t r o f i t Layout 126 4.5 C a l g a r y Bonnybrook R e t r o f i t B i o r e a c t o r 127 Layout 4.6 Edmonton Gold Bar P l a n t Flowsheet ( E x i s t i n g ) 140 4.7 Edmonton Gold Bar P l a n t Layout ( E x i s t i n g ) 141 4.8 Edmonton Gold Bar R e t r o f i t Flowsheet 145 4.9 Edmonton Gold Bar R e t r o f i t Layout 146 4.10 Edmonton Gold Bar R e t r o f i t B i o r e a c t o r 147 Layout 4.11 Edmonton Gold Bar Process Options 149 4.12 Regina P l a n t Layout ( E x i s t i n g ) 160 4.13 Regina R e t r o f i t . Flowsheet 165 4.14 Regina R e t r o f i t Layout 166 4.15 Regina R e t r o f i t B i o r e a c t o r Layout 168 (x) PAGE NO. NC i. TITLE 4. 16 Regina < Chemical Phosphorus Removal Flowsheet 170 4. 17 Saskatoon P l a n t Flowsheet ( E x i s t i n g ) 179 4. 18 Saskatoon P l a n t Layout ( E x i s t i n g ) 180 4. 19 Saskatoon R e t r o f i t Flowsheet 184 4. 20 Saskatoon R e t r o f i t Layout 185 4. 21 Saskatoon R e t r o f i t B i o r e a c t o r Layout 186 4. 22 Windsor Combined P l a n t Flowsheet ( E x i s t i n g ) 194 4. 23 Windsor Combined P l a n t Layout ( E x i s t i n g ) 195 4. 24 Windsor R e t r o f i t Flowsheet 201 4. 25 Windsor R e t r o f i t Layout 202 4. 26 Windsor R e t r o f i t B i o r e a c t o r Layouts 203 4. 27 Grimsby P l a n t Flowsheet ( E x i s t i n g ) 214 4. 28 v Grimsby P l a n t Layout ( E x i s t i n g ) 215 4. 29 Grimsby R e t r o f i t Flowsheet 220 4. 30 Grimsby R e t r o f i t Layout 221 4. 31 Grimsby R e t r o f i t B i o r e a c t o r Layout 223 4. 32 T u r b o r a t o r Schematic 225 4. 33 M i l t o n P l a n t Flowsheet ( E x i s t i n g ) 233 4. 34 M i l t o n P l a n t Layout ( E x i s t i n g ) 234 4. 35 M i l t o n R e t r o f i t Flowsheet 238 4. 36 M i l t o n R e t r o f i t Layout 239 4. 37 M i l t o n R e t r o f i t B i o r e a c t o r Layout 240 4. 38 E l m i r a P l a n t Flowsheet ( E x i s t i n g ) 250 4. .39 E l m i r a R e t r o f i t Flowsheet 255 4. ,40 E l m i r a R e t r o f i t B i o r e a c t o r Layouts 256 4. ,41 W e l l e s l e y P l a n t Flowsheet/Layout ( E x i s t i n g ) 265 4. .42 W e l l e s l e y R e t r o f i t Flowsheet/Layout 268 ( x i ) A C K N O W L E D G E M E N T I would l i k e t o thank Dr. W.K. Oldham f o r h i s a s s i s t a n c e w i t h both the r e s e a r c h and the p r e p a r a t i o n of t h i s t h e s i s . I would a l s o l i k e t o acknowledge the a s s i s t a n c e of the C i t i e s o f Calgary, Edmonton, Regina, Saskatoon and Windsor; the Region a l M u n i c i p a l i t i e s of H a l t o n and Niagara; and the O n t a r i o and Quebec M i n i s t r i e s of the Environment, i n s u p p l y i n g the i n f o r m a t i o n which formed the b a s i s f o r the r e s e a r c h . A l s o d e s e r v i n g of thanks are the N a t u r a l Sciences, and E n g i n e e r i n g Research C o u n c i l of Canada f o r p r o v i d i n g f i n a n c i a l support; Ms. Peggy Van Zante f o r word p r o c e s s i n g s e r v i c e s ; and M i c h e l l e M o r r i s o n f o r p u t t i n g up w i t h me d u r i n g my s t a y at UBC. - 1 -1.0 INTRODUCTION The requirement f o r phosphorus removal from m u n i c i p a l wastewater i s widespread throughout Canada. In an i n v e n t o r y of m u n i c i p a l wastewater treatment systems i n Canada, Environment Canada (1986) show t h a t New Brunswick, Quebec, O n t a r i o , Manitoba, Saskatchewan, A l b e r t a and B r i t i s h Columbia have a l l s e t phosphorus d i s c h a r g e l i m i t s f o r e f f l u e n t s from a t l e a s t one of t h e i r sewage treatment p l a n t s . The O n t a r i o M i n i s t r y of the Environment (1987) r e p o r t s t h a t i n O n t a r i o a lone, 250 of the 403 m u n i c i p a l wastewater treatment p l a n t s have some form of phosphorus removal s t a n d a r d a s s o c i a t e d w i t h t h e i r d i s c h a r g e p e r m i t s . The most e s t a b l i s h e d and, hence, widespread method of phosphorus removal i n Canada i s c h e m i c a l p r e c i p i t a t i o n . In t h i s method, metal s a l t s ( g e n e r a l l y aluminum s u l p h a t e , sodium aluminate, f e r r i c c h l o r i d e , f e r r o u s c h l o r i d e or f e r r o u s s u l p h a t e ) or lime ( c a l c i u m oxide or c a l c i u m hydrate) are added a t one or more p o i n t s i n the wastewater treatment p r o c e s s . These r e a c t w i t h the phosphorus i n the wastewater t o form i n s o l u b l e metal-phosphate p r e c i p i t a t e s which are then removed through s e d i m e n t a t i o n . A complete summary of the t h e o r y and technology a s s o c i a t e d w i t h c h e m i c a l phosphorus removal i s p r o v i d e d by the USEPA (1987). Chemical phosphorus removal i s employed i n a l l but one of the wastewater treatment p l a n t s i n Canada which c u r r e n t l y remove phosphorus. - 2 -A m o r e r e c e n t l y d e v e l o p e d t e c h n o l o g y f o r p h o s p h o r u s r e m o v a l i s k n o w n a s e n h a n c e d b i o l o g i c a l p h o s p h o r u s ( B i o - P ) r e m o v a l . T h i s t e c h n o l o g y i n v o l v e s c r e a t i n g c e r t a i n c o n d i t i o n s i n t h e b i o r e a c t o r o f a s e c o n d a r y w a s t e w a t e r t r e a t m e n t p l a n t w h i c h p r o m o t e t h e g r o w t h o f s p e c i f i c t y p e s o f b a c t e r i a ( h e r e a f t e r c a l l e d B i o - P b a c t e r i a ) . B e c a u s e o f t h e n a t u r e o f t h e i r m e t a b o l i c p a t h w a y s , t h e s e b a c t e r i a c o n s u m e l a r g e a m o u n t s o f p h o s p h o r u s r e l a t i v e t o t h o s e f o u n d i n c o n v e n t i o n a l s e c o n d a r y t r e a t m e n t p l a n t s . C o n d i t i o n s r e q u i r e d f o r t h e g r o w t h o f B i o - P b a c t e r i a a r e s u m m a r i z e d a s f o l l o w s : 1 . T h e b a c t e r i a m u s t b e s u b j e c t e d t o p e r i o d s o f a n a e r o b i c c o n d i t i o n s , f o l l o w e d b y p e r i o d s o f a e r o b i c c o n d i t i o n s . A n a e r o b i c c o n d i t i o n s r e f e r t o t h e a b s e n c e o f b o t h d i s s o l v e d o x y g e n a n d f r e e n i t r a t e ( N 0 3 ) . 2 . W h i l e b e i n g s u b j e c t e d t o a n a e r o b i c c o n d i t i o n s , t h e b a c t e r i a m u s t h a v e a s u p p l y o f v o l a t i l e f a t t y a c i d s ( V F A ' s ) a v a i l a b l e t o t h e m f o r c o n s u m p t i o n . P h o s p h o r u s r e m o v a l i s a c h i e v e d t h r o u g h t h e w a s t i n g o f b a c t e r i a f r o m t h e p r o c e s s . N u m e r o u s p i l o t - s c a l e a n d f u l l - s c a l e p r o j e c t s h a v e d e m o n s t r a t e d t h a t u n d e r c e r t a i n c o n d i t i o n s , s u f f i c i e n t q u a n t i t i e s o f B i o - P b a c t e r i a c a n b e c u l t i v a t e d i n c o n v e n t i o n a l w a s t e w a t e r t r e a t m e n t p r o c e s s e s , s u c h t h a t p h o s p h o r u s c a n b e r e m o v e d t o l e v e l s w e l l b e l o w 1 . 0 m g / L a s t o t a l p h o s p h o r u s . - 3 -B i o - P t e c h n o l o g y h a s b e e n d e v e l o p e d t h r o u g h o u t t h e w o r l d i n C a n a d a , t h e U n i t e d S t a t e s , S o u t h A f r i c a , J a p a n , F r a n c e , I t a l y a n d D e n m a r k . C u r r e n t l y , t h e m o s t w i d e s p r e a d f u l l - s c a l e a p p l i c a t i o n o f t h e t e c h n o l o g y i s i n S o u t h A f r i c a a n d t h e U n i t e d S t a t e s . P a e p c k e ( 1 9 8 5 ) e s t i m a t e s t h a t a s o f 1 9 8 5 , a p p r o x i m a t e l y 3 0 S o u t h A f r i c a n m u n i c i p a l w a s t e w a t e r t r e a t m e n t p l a n t s w e r e u s i n g t h e B i o - P p r o c e s s , w h i l e T e t r e a u l t e t a l . ( 1 9 8 5 ) r e p o r t t h a t a s o f A p r i l 1 9 8 4 , 2 9 B i o - P f a c i l i t i e s w e r e i n e i t h e r t h e d e s i g n , c o n s t r u c t i o n o r o p e r a t i o n s t a g e s i n t h e U n i t e d S t a t e s . T h e u s e o f B i o - P t e c h n o l o g y h a s b e e n v e r y l i m i t e d i n C a n a d a . A t t h e p r e s e n t t i m e t h e o n l y o p e r a t i o n a l p l a n t i s a 3 2 2 , 0 0 0 m / d a c t i v a t e d s l u d g e p l a n t i n K e l o w n a , B . C . T w o o t h e r B i o - P p l a n t s a r e p r e s e n t l y b e i n g d e s i g n e d f o r P e n t i c t o n , B . C . ( 1 8 , 0 0 0 m 3 / d ) a n d W e s t b a n k , B . C . ( 4 , 5 0 0 m 3 / d ) . 3 F u l l - s c a l e t e s t s h a v e b e e n r u n a t t h e 3 4 0 , 0 0 0 m / d E d m o n t o n . . 3 G o l d B a r t r e a t m e n t p l a n t ( S h i v ^ i , 1 9 8 7 ) a n d t h e 3 6 , 3 0 0 m / d W i n d s o r L i t t l e R i v e r P o l l u t i o n c o n t r o l p l a n t . B i o - P r e m o v a l o f f e r s s o m e a d v a n t a g e s o v e r c h e m i c a l p h o s p h o r u s r e m o v a l . T h e m o s t s i g n i f i c a n t i s t h e p o t e n t i a l f o r r e d u c e d o p e r a t i n g c o s t s t h r o u g h c h e m i c a l u s a g e r e d u c t i o n s . O t h e r a d v a n t a g e s i n c l u d e p o t e n t i a l l y r e d u c e d s l u d g e h a n d l i n g a n d d i s p o s a l c o s t s t h r o u g h r e d u c t i o n i n c h e m i c a l s l u d g e v o l u m e s . - 4 -T h e r e a r e a l s o a n u m b e r o f d i s a d v a n t a g e s a s s o c i a t e d w i t h t h e t e c h n o l o g y w h e n c o m p a r e d t o a c h e m i c a l r e m o v a l p r o c e s s , w i t h t h e m a j o r o n e b e i n g t h a t t h e c a p i t a l c o s t o f a B i o - P p l a n t i s h i g h e r b e c a u s e o f t h e a d d i t i o n a l f a c i l i t i e s w h i c h a r e r e q u i r e d . O t h e r d i s a d v a n t a g e s i n c l u d e i n c r e a s e d l a b o r a t o r y a n a l y s i s r e q u i r e m e n t s , h i g h e r e n e r g y c o n s u m p t i o n a n d , d e p e n d i n g u p o n t h e c o n f i g u r a t i o n o f t h e B i o - P p r o c e s s , p o t e n t i a l l y h i g h e r s l u d g e p r o d u c t i o n . I n a d d i t i o n , s o m e o p e r a t o r r e - t r a i n i n g i s r e q u i r e d f o r t h e o p e r a t i o n o f a B i o - P p l a n t . B e c a u s e B i o - P t e c h n o l o g y i s r e l a t i v e l y n e w , t h e m a j o r i t y o f r e s e a r c h h a s b e e n r e l a t e d t o t h e d e m o n s t r a t i o n o f t h e p r o c e s s a n d t h e d e v e l o p m e n t o f a n u n d e r s t a n d i n g o f h o w t h e p r o c e s s w o r k s . L i m i t e d w o r k h a s b e e n d o n e o n a s s e s s i n g t h e p o t e n t i a l f o r t h e u s e o f t h e t e c h n o l o g y . T h i s i s p a r t i c u l a r l y i n e v i d e n c e i n C a n a d a . C a n v i r o e t a l . ( 1 9 8 6 ) c o n s i d e r e d t h e t e c h n i c a l a n d e c o n o m i c f e a s i b i l i t y o f r e t r o f i t t i n g m u n i c i p a l w a s t e w a t e r t r e a t m e n t p l a n t s f o r B i o - P r e m o v a l b y p r e p a r i n g e c o n o m i c a n a l y s e s f o r n i n e h y p o t h e t i c a l p l a n t s h a v i n g d i f f e r e n t p r o c e s s e s , c a p a c i t i e s a n d p h o s p h o r u s r e m o v a l s t a n d a r d s . H o w e v e r , b e c a u s e t h i s r e p o r t d i d n o t c o n s i d e r r e g i o n a l d i f f e r e n c e s i n s e w a g e c h a r a c t e r i s t i c s , c h e m i c a l a v a i l a b i l i t y a n d c o s t , s l u d g e h a n d l i n g p r a c t i c e s a n d s l u d g e d i s p o s a l r e g u l a t i o n s , i t p r o v i d e s o n l y a f r a m e w o r k f r o m w h i c h s i t e s p e c i f i c - 5 -c o m p a r a t i v e a n a l y s e s c a n b e p e r f o r m e d . I t i s t h e r e f o r e , d i f f i c u l t t o d r a w d e f i n i t i v e c o n c l u s i o n s r e g a r d i n g t h e p o t e n t i a l f o r t h e u s e o f t h e p r o c e s s i n C a n a d a f r o m t h i s w o r k . E v a n s a n d C r a w f o r d ( 1 9 8 5 ) c o m m e n t i n g e n e r a l o n t h e p o t e n t i a l f o r t h e u s e o f B i o - P r e m o v a l a n d p r e s e n t a s a m p l e e c o n o m i c a n a l y s i s f o r a h y p o t h e t i c a l A l b e r t a p l a n t . T h e i r c o m m e n t s , h o w e v e r , f o c u s m o r e o n i t e m s w h i c h s h o u l d b e c o n s i d e r e d i n a s i t e s p e c i f i c a n a l y s i s r a t h e r t h a n o n t h e a p p l i c a b i l i t y o f t h e t e c h n o l o g y t o t h e C a n a d i a n s i t u a t i o n . S i t e s p e c i f i c s t u d i e s w e r e d o n e f o r t h e c i t i e s o f E d m o n t o n ( S h i v j i , 1 9 8 7 ) , R e g i n a ( S t a n l e y A s s o c i a t e s , 1 9 8 6 A ) a n d P e n t i c t o n ( S t a n l e y A s s o c i a t e s , 1 9 8 6 ) a n d t h e t o w n o f W e s t b a n k , B . C . ( K n i g h t a n d P i e s o l d L t d . , 1 9 8 5 ) . H o w e v e r , o n l y S h i v j i ( 1 9 8 7 ) d i r e c t l y c o m p a r e s t h e e c o n o m i c s o f t h e t w o p h o s p h o r u s r e m o v a l t e c h n o l o g i e s a n d h e n c e , c o n c l u s i o n s r e g a r d i n g t h e o v e r a l l f e a s i b i l i t y o f B i o - P t e c h n o l o g y i n C a n a d a a r e d i f f i c u l t t o d r a w f r o m t h e s e s t u d i e s . T h e p u r p o s e o f t h i s r e s e a r c h i s , t h e r e f o r e , t o a s s e s s t h e p o t e n t i a l f o r t h e u s e o f B i o - P t e c h n o l o g y i n C a n a d i a n m u n i c i p a l w a s t e w a t e r t r e a t m e n t p l a n t s . T h e r e s u l t s o f t h e r e s e a r c h w i l l a s s i s t m u n i c i p a l i t i e s a n d c o n s u l t a n t s i n m a k i n g d e c i s i o n s o n t h e t y p e o f w a s t e w a t e r t r e a t m e n t p r o c e s s t o i n s t a l l . I n a d d i t i o n , t h e r e s u l t s s h o u l d a s s i s t w i t h t h e d i r e c t i o n o f f u t u r e B i o - P r e s e a r c h . - 6 -I n a s s e s s i n g t h e f e a s i b i l i t y o f B i o - P t e c h n o l o g y i n C a n a d a , i t w a s d e c i d e d t o c a r r y o u t c o m p a r a t i v e s t u d i e s o n a r e p r e s e n t a t i v e c r o s s - s e c t i o n o f e x i s t i n g m u n i c i p a l w a s t e w a t e r t r e a t m e n t p l a n t s a c r o s s t h e c o u n t r y . N i n e p l a n t s f r o m O n t a r i o , S a s k a t c h e w a n a n d A l b e r t a w e r e s t u d i e d . S o m e o f t h e s e p l a n t s h a d e x i s t i n g p h o s p h o r u s r e m o v a l r e q u i r e m e n t s a n d i n t h e o t h e r s , f u t u r e r e q u i r e m e n t s w e r e a n t i c i p a t e d . R e t r o f i t d e s i g n s , i n c o p o r a t i n g B i o - P t e c h n o l o g y i n t o e a c h p l a n t , w e r e p r e p a r e d . T h e s e w e r e c o m p a r e d w i t h e x i s t i n g c h e m i c a l p h o s p h o r u s r e m o v a l o p e r a t i o n s f o r p l a n t s c u r r e n t l y r e m o v i n g p h o s p h o r u s , o r w i t h n e w c h e m i c a l p h o s p h o r u s r e m o v a l d e s i g n s f o r p l a n t s n o t h a v i n g e f f l u e n t p h o s p h o r u s s t a n d a r d s . T h e i n c r e m e n t a l c o s t s , b o t h c a p i t a l a n d o p e r a t i n g , a s s o c i a t e d w i t h B i o - P t e c h n o l o g y a s c o m p a r e d t o a n e q u i v a l e n t c h e m i c a l r e m o v a l t e c h n o l o g y , w e r e e s t i m a t e d a n d t h e e c o n o m i c s o f B i o - P r e m o v a l w e r e e v a l u a t e d f o r e a c h p l a n t . T h r o u g h a g e n e r a l a n a l y s i s o f a l l n i n e p l a n t s , c o n c l u s i o n s r e g a r d i n g t h e p o t e n t i a l f o r B i o - P r e m o v a l i n C a n a d a w e r e d e v e l o p e d . I t w a s d e c i d e d t o c a r r y o u t t h i s a n a l y s i s o n a c t u a l , v e r s u s h y p o t h e t i c a l , p l a n t s a s i t w a s f e l t t h a t t h e a d v a n t a g e s a n d d i s a d v a n t a g e s o f t h e B i o - P t e c h n o l o g y w o u l d b e c o m e m o r e e v i d e n t i n a r e a l l i f e s e t t i n g . I n a d d i t i o n , b y s e l e c t i n g p l a n t s f r o m a c r o s s t h e c o u n t r y , d i f f e r e n c e s b e t w e e n r e g i o n a l c o n d i t i o n s , e c o n o m i e s a n d r e g u l a t i o n s c o u l d b e c o n s i d e r e d i n t h e a n a l y s i s . - 7 -T h e p r e s e n t a t i o n o f t h i s t h e s i s b a s i c a l l y f o l l o w s t h e o r d e r i n w h i c h t h e r e s e a r c h w a s c a r r i e d o u t . B a c k g r o u n d m a t e r i a l t o t h e r e s e a r c h i s i n i t i a l l y p r e s e n t e d i n S e c t i o n 2 . 0 . I n t h i s s e c t i o n t h e t h e o r y a n d d e v e l o p m e n t o f B i o - P t e c h n o l o g y i s r e v i e w e d a l o n g w i t h p a s t a s s e s s m e n t s o f t h e t e c h n i c a l a n d e c o n o m i c f e a s i b i l i t y o f B i o - P r e m o v a l . T h r o u g h t h i s r e v i e w , a n u n d e r s t a n d i n g o f t h e p r e s e n t s t a t e o f t h e t e c h n o l o g y i s o b t a i n e d . S e c t i o n 3 . 0 o u t l i n e s i n d e t a i l t h e m e t h o d o l o g y u s e d i n t h e e x e c u t i o n o f t h i s r e s e a r c h . W i t h i n t h i s s e c t i o n , t h e r a t i o n a l e b e h i n d t h e v a r i o u s a s p e c t s o f t h e r e s e a r c h a r e d i s c u s s e d . I n p a r t i c u l a r , t h e r a t i o n a l e f o r t h e s e l e c t i o n o f t h e p l a n t s s t u d i e d i s p r e s e n t e d . A l s o p r e s e n t e d i n t h i s s e c t i o n a r e t h e b a s e s f o r t h e r e t r o f i t d e s i g n s , t h e c o s t e s t i m a t i n g t e c h n i q u e s a n d t h e m e t h o d o f e c o n o m i c a n a l y s i s u s e d . S e c t i o n 4 . 0 p r e s e n t s t h e r e s u l t s o f t h e a n a l y s i s . E a c h p l a n t i s c o n s i d e r e d i n d i v i d u a l l y , w i t h d i s c u s s i o n s r e g a r d i n g t h e p r e s e n t o p e r a t i o n , t h e m o d i f i c a t i o n s r e q u i r e d f o r c o n v e r s i o n t o B i o - P a n d c h e m i c a l p h o s p h o r u s r e m o v a l ( i f a p p l i c a b l e ) , a n d t h e i n c r e m e n t a l c a p i t a l a n d o p e r a t i n g c o s t s p r o v i d e d . T h e r e s u l t s o f t h e e c o n o m i c a n a l y s i s , i n w h i c h i n t e r n a l r a t e s o f r e t u r n ( I R R ' s ) w e r e c a l c u l a t e d f o r t h e c a p i t a l r e q u i r e d t o r e t r o f i t e a c h p l a n t , a r e a l s o p r e s e n t e d . - 8 -S e c t i o n 5 . 0 p r o v i d e s a d i s c u s s i o n o f t h e r e s u l t s g e n e r a t e d i n S e c t i o n 4 . 0 A n a s s e s s m e n t o f t h e o v e r a l l p o t e n t i a l f o r B i o - P t e c h n o l o g y i s m a d e t h r o u g h a n a n a l y s i s o f t h e r e s u l t s . C o n c l u s i o n s a n d r e c o m m e n d a t i o n s a r e d e v e l o p e d i n t h i s s e c t i o n a n d t h e n f o r m a l l y p r e s e n t e d i n S e c t i o n 6 . 0 . - 9 -2.0 B A C K G R O U N D T O S T U D Y T h e o b j e c t i v e o f t h i s s e c t i o n i s t o p r o v i d e a n u n d e r s t a n d i n g o f b o t h t h e B i o - P r e m o v a l p r o c e s s a n d t h e p r e s e n t s t a t u s o f i t s d e v e l o p m e n t i n f u l l s c a l e w a s t e w a t e r t r e a t m e n t p r o c e s s e s . T h e b i o c h e m i s t r y o f B i o - P r e m o v a l i s i n i t i a l l y d i s c u s s e d i n S e c t i o n 2 . 1 . T h i s i s f o l l o w e d i n S e c t i o n 2 . 2 b y a r e v i e w o f t h e v a r i o u s c o m m e r c i a l a n d e x p e r i m e n t a l B i o - P p r o c e s s e s w h i c h h a v e b e e n d e v e l o p e d . A d i s c u s s i o n o n t h e s t a t u s o f B i o - P k i n e t i c m o d e l l i n g i s a l s o p r e s e n t e d i n t h i s s e c t i o n , a s i t h a s a s i g n i f i c a n t i m p a c t o n t h e p r o c e d u r e s u s e d i n t h e d e s i g n o f B i o - P p l a n t s . F i n a l l y , r e v i e w s o f p r e v i o u s a s s e s s m e n t s o f t h e t e c h n i c a l a n d e c o n o m i c f e a s i b i l i t y o f B i o - P r e m o v a l a r e p r e s e n t e d i n S e c t i o n 2 . 3 . 2 . 1 B i o c h e m i s t r y o f B i o l o g i c a l P h o s p h o r u s R e m o v a l B e c a u s e p h o s p h o r u s i s a n e s s e n t i a l n u t r i e n t r e q u i r e d f o r b a c t e r i a l g r o w t h , s o m e r e m o v a l i s a c h i e v e d i n a l l b i o l o g i c a l w a s t e w a t e r t r e a t m e n t p r o c e s s e s . I n c o n v e n t i o n a l b i o l o g i c a l t r e a t m e n t p l a n t s , a p p r o x i m a t e l y 1 m g / L o f p h o s p h o r u s i s r e q u i r e d t o s u p p o r t t h e r e m o v a l o f 1 0 0 m g / L o f 5 - d a y b i o c h e m i c a l o x y g e n d e m a n d ( B O D , . ) . F o r t y p i c a l C a n a d i a n m u n i c i p a l s e w a g e , t h i s g e n e r a l l y r e s u l t s i n p h o s p h o r u s r e m o v a l s o f 2 m g - P / L o r 1 0 - 3 0 % , a n d b i o l o g i c a l s o l i d s p h o s p h o r u s c o n t e n t s f r o m 1.5% t o 2 . 0 % o n a d r y w e i g h t b a s i s . - 1 0 -H o w e v e r , i n B i o - P r e m o v a l p l a n t s , c o n d i t i o n s a r e c r e a t e d i n t h e b i o r e a c t o r w h i c h p r o m o t e t h e g r o w t h o f s p e c i f i c t y p e s o f b a c t e r i a w h i c h c o n s u m e c o m p a r a t i v e l y l a r g e a m o u n t s o f p h o s p h o r u s . D a i g g e r e t a l . ( 1 9 8 7 ) r e p o r t b i o l o g i c a l s o l i d s p h o s p h o r u s c o n t e n t s o f u p t o 14% d u r i n g p i l o t - s c a l e i n v e s t i g a t i o n s . K r i e s s e l a n d E r a l p ( 1 9 8 6 ) r e p o r t t h a t t y p i c a l B i o - P s l u d g e s c o n t a i n 4 t o 6% p h o s p h o r u s o n a d r y w e i g h t , t o t a l s u s p e n d e d s o l i d s ( T S S ) b a s i s . T h e r e f o r e , a s s u m i n g t h a t a t y p i c a l B i o - P s l u d g e c o n t a i n s 6% p h o s p h o r u s b y w e i g h t , a n d a t y p i c a l c o n v e n t i o n a l w a s t e w a t e r t r e a t m e n t s l u d g e c o n t a i n s 2% p h o s p h o r u s , t h e B i o - P b a c t e r i a s h o u l d r e m o v e r o u g h l y t h r e e t i m e s a s m u c h p h o s p h o r u s a s t h e c o n v e n t i o n a l b a c t e r i a . A c i n e t o b a c t e r w a s i n i t i a l l y f o u n d t o b e t h e s p e c i e s o f b a c t e r i a r e s p o n s i b l e f o r e n h a n c e d B i o - P r e m o v a l ( F u h s a n d C h e n , 1 9 7 5 ) . S i n c e t h e n , o t h e r b a c t e r i a h a v e b e e n s h o w n t o p o s s e s s t h i s a b i l i t y t o r e m o v e l a r g e a m o u n t s o f p h o s p h o r u s ( B r o d i s c h a n d J o i n e r , 1 9 8 3 ; G e r s b e r g a n d A l l e n , 1 9 8 5 ) . A c i n e t o b a c t e r , h o w e v e r , i s s t i l l b e l i e v e d t o b e t h e b a c t e r i a p r e d o m i n a t e l y r e s p o n s i b l e f o r B i o - P r e m o v a l . T h e r e a s o n f o r t h e p r o l i f e r a t i o n o f B i o - P b a c t e r i a i n b i o r e a c t o r s , a n d h e n c e t h e r e a s o n f o r t h e o c c u r r e n c e o f e n h a n c e d B i o - P r e m o v a l , h a s b e e n t h e s u b j e c t o f c o n s i d e r a b l e r e s e a r c h o v e r t h e p a s t 2 5 y e a r s . T h e f o l l o w i n g p o i n t s s u m m a r i z e t h e r e s u l t s o f t h i s r e s e a r c h : - 1 1 -i ) I n o r d e r t o p r o m o t e t h e g r o w t h o f B i o - P b a c t e r i a i n a s e c o n d a r y t r e a t m e n t p r o c e s s , t h e b i o l o g i c a l s o l i d s m u s t b e e x p o s e d t o a n a e r o b i c c o n d i t i o n s f o l l o w e d b y a e r o b i c c o n d i t i o n s ( B a r n a r d , 1 9 7 4 ) . A n a e r o b i c c o n d i t i o n s r e f e r t o t h e a b s e n c e o f d i s s o l v e d o x y g e n ( D O ) a n d n i t r a t e ( N 0 3 ) . i i ) T h e g r o w t h o f B i o - P b a c t e r i a i s d e p e n d e n t u p o n t h e p r e s e n c e o f s u f f i c i e n t q u a n t i t i e s o f V F A ' s d u r i n g t h e a n a e r o b i c c o n d i t i o n s o u t l i n e d i n ( i ) ( H a l l , N i c h o l l s a n d O s b o r n e , 1 9 7 8 ; R e n s i n k e t a l . , 1 9 8 1 ) . O l d h a m ( 1 9 8 6 ) s u g g e s t s t h a t m i n i m u m V F A c o n c e n t r a t i o n s o f 1 5 m g / L ( a s a c e t a t e ) a r e r e q u i r e d u n d e r a n a e r o b i c c o n d i t i o n s t o f a c i l i t a t e t h e r e m o v a l o f 4 t o 5 m g / L o f p h o s p h o r u s . i i i ) D u r i n g a e r o b i c c o n d i t i o n s , B i o - P b a c t e r i a t a k e u p p h o s p h o r u s f r o m t h e w a s t e w a t e r a n d s t o r e i t a s i n t e r c e l l u l a r p o l y p h o s p h a t e . U n d e r a n a e r o b i c c o n d i t i o n s p o l y p h o s p h a t e i s m e t a b o l i z e d a n d r e l e a s e d f r o m t h e c e l l a s p h o s p h a t e ( S h a p i r o e t a l . , 1 9 6 7 ) . i v ) B i o - P b a c t e r i a m e t a b o l i s m i s b a s e d o n t h e u s e o f s t o r e d p o l y p h o s p h a t e t o p r o v i d e e n e r g y f o r t h e s t o r a g e o f V F A ' s a s p o l y - p - h y d r o x y b u t y r a t e ( P H B ) u n d e r a n a -- 12 -e r o b i c c o n d i t i o n s , a n d t h e r e p l e n i s h m e n t o f t h e p o l y p h o s p h a t e r e s e r v e t h r o u g h e n e r g y p r o d u c t i o n v i a P H B o r e x t r a - c e l l u l a r c a r b o n b r e a k d o w n u n d e r a e r o b i c c o n d i t i o n s ( C o m e a u e t a l . , 1 9 8 6 ) . A s i m p l i f i e d i l l u s t r a t i o n o f t h i s m e c h a n i s m i s p r e s e n t e d i n F i g u r e 2 . 1 . v ) B e c a u s e o f t h e c o n d i t i o n s c r e a t e d i n t h e b i o r e a c t o r a s o u t l i n e d i n ( i ) a n d ( i i ) , B i o - P b a c t e r i a a r e a b l e t o o u t - c o m p e t e c o n v e n t i o n a l a e r o b i c a n d f a c u l t a t i v e b a c t e r i a ( M a r a i s e t a l . 1 9 8 3 ) . v i ) U n d e r p r o l o n g e d a e r a t i o n ( e . g . a e r o b i c d i g e s t i o n ) B i o - P b a c t e r i a r e l e a s e s t o r e d p o l y p h o s p h a t e , a s p h o s p h a t e , i n t o s o l u t i o n ( A n d e r s o n , 1 9 8 8 ; C o m e a u , 1 9 8 8 ) . W h i l e t h e B i o - P r e m o v a l m e c h a n i s m i s s t i l l n o t f u l l y u n d e r -s t o o d , t h e a b o v e s i x p o i n t s g e n e r a l l y f o r m t h e b a s i s o f t h e p r e s e n t u n d e r s t a n d i n g o f t h e B i o - P r e m o v a l m e c h a n i s m . A s a r e s u l t , t h e y w i l l b e u s e d e x t e n s i v e l y i n e s t a b l i s h i n g t h e d e s i g n b a s i s f o r t h e B i o - P r e m o v a l r e t r o f i t s . F r o m t h e a b o v e s i x p o i n t s i t i s e v i d e n t t h a t t h e c h a r a c t e r i s t i c s o f t h e i n f l u e n t w a s t e w a t e r a r e v e r y i m p o r t a n t t o t h e s u c c e s s o f B i o - P r e m o v a l . T h e k e y c h a r a c t e r i s t i c s o f t h e i n f l u e n t a r e a s f o l l o w s : ANAEROBIC CONDITIONS AEROBIC CONDITIONS F I G U R E 2 . 1 - S I M P L I F I E D M E C H A N I S M F O R B I O L O G I C A L P H O S P H O R U S R E M O V A L - 14 -i ) c a r b o n / p h o s p h o r u s r a t i o i i ) c a r b o n / n i t r o g e n r a t i o s f o r c o m b i n e d n i t r o g e n a n d p h o s p h o r u s r e m o v a l s y s t e m s i i i ) q u a n t i t i e s o f V F A ' s T h e c a r b o n t o p h o s p h o r u s r a t i o i s v e r y i m p o r t a n t a s i t s e t s a l i m i t o n t h e a m o u n t o f p h o s p h o r u s w h i c h c a n b e r e m o v e d f r o m t h e w a s t e w a t e r . S i n c e t h e c o n s u m p t i o n o f e x t e r n a l c a r b o n s u b s t r a t e s a n d i n t e r n a l l y s t o r e d P H B b y B i o - P b a c t e r i a u n d e r a e r o b i c c o n d i t o n s s e t s u p a p r o t o n m o t i v e f o r c e ( p m f ) a c r o s s t h e b a c t e r i a l c e l l m e m b r a n e w h i c h i s t h e n u s e d f o r p h o s p h a t e t r a n s f e r i n t o t h e c e l l ( C o m e a u e t a l . , 1 9 8 6 ) , i t s t a n d s t o r e a s o n t h a t p h o s p h o r u s u p t a k e i s l i m i t e d b y t h e a m o u n t o f c a r b o n a v a i l a b l e f o r c o n s u m p t i o n . I n d e e d , m a n y r e p o r t s o n v a r i o u s B i o - P r e m o v a l p r o c e s s e s r e c o m m e n d s p e c i f i c c a r b o n / p h o s p h o r u s r a t i o s ( R o y F . W e s t o n I n c . , 1 9 8 5 ; E v a n s a n d C r a w f o r d , 1 9 8 5 ) . T h e c a r b o n t o n i t r o g e n r a t i o i s i m p o r t a n t f o r s y s t e m s w h i c h r e m o v e b o t h n i t r o g e n a n d p h o s p h o r u s . S h o u l d i n s u f f i c i e n t c a r b o n b e p r e s e n t t o a c c o m m o d a t e d e n i t r i f i c a t i o n , t h e p o t e n t i a l e x i s t s f o r r e c y c l e d n i t r a t e s t o i n t e r f e r e w i t h t h e c r e a t i o n o f a n a e r o b i c c o n d i t i o n s . T h i s w i l l b e m o r e f u l l y e x p l a i n e d w h e n t h e i n d i v i d u a l B i o - P p r o c e s s e s a r e d i s c u s s e d . F o r a d i s c u s s i o n o f t h e m e c h a n i s m s i n v o l v e d i n b i o l o g i c a l n i t r o g e n r e m o v a l r e f e r t o A p p e n d i x B . - 1 5 -T h e i m p o r t a n c e o f t h e c a r b o n / n i t r o g e n r a t i o h a s b e e n s t r e s s e d b y m a n y r e s e a r c h e r s . E k a m a e t a l . ( 1 9 8 4 ) , R o y F . W e s t o n I n c . ( 1 9 8 5 ) a n d E v a n s a n d C r a w f o r d , ( 1 9 8 5 ) , a l l p r e s e n t l i m i t s o n t h e c a r b o n / n i t r o g e n r a t i o s f o r v a r i o u s B i o - P p r o c e s s e s . T h e m o s t i m p o r t a n t c h a r a c t e r i s i t i c o f t h e i n f l u e n t f o r B i o - P r e m o v a l i s i t s V F A c o n t e n t . W i t h o u t s u f f i c i e n t V F A ' s , B i o - P b a c t e r i a c a n n o t s t o r e P H B i n t h e a n a e r o b i c z o n e a n d h e n c e , d o n o t o b t a i n a n a d v a n t a g e o v e r c o n v e n t i o n a l f a c u l t a t i v e a n d a e r o b i c b a c t e r i a . N i c h o l l s e t a l . ( 1 9 8 6 ) r e p o r t o n t h e i m p r o v e m e n t i n p h o s p h o r u s r e m o v a l p e r f o r m a n c e a t t h e J o h a n n e s b u r g N o r t h e r n W o r k s w a s t e w a t e r t r e a t m e n t p l a n t t h r o u g h t h e a d d i t i o n o f V F A ' s ( g e n e r a t e d b y f e r m e n t a t i o n o f p r i m a r y s l u d g e ) t o t h e a n a e r o b i c z o n e o f t h e b i o r e a c t o r . O l d h a m ( 1 9 8 5 ) p r e s e n t e d r e s u l t s s h o w i n g s u p e r i o r p h o s p h o r u s r e m o v a l i n o n e t r a i n o f t h e K e l o w n a P o l l u t i o n C o n t r o l P l a n t w h e r e V F A ' s h a d b e e n a d d e d t h r o u g h p r i m a r y s l u d g e f e r m e n t a t i o n , a s c o m p a r e d t o t h e s e c o n d t r a i n w h e r e n o a d d i t i o n w a s c a r r i e d o u t . 2 . 2 P r o c e s s D e v e l o p m e n t E x c e s s p h o s p h o r u s r e m o v a l f r o m w a s t e w a t e r w i t h o u t c h e m i c a l a d d i t i o n w a s f i r s t r e p o r t e d b y G r e e n b e r g e t a l . ( 1 9 5 5 ) a n d S r i n a t h e t a l . ( 1 9 5 9 ) . G r e e n b e r g e t a l . s t a t e d t h a t " p h o s p h o r u s u p t a k e b y a n a c t i v a t e d s l u d g e m a y e x c e e d i t s " r e q u i r e m e n t s " i f - 16 -t h e p h o s p h o r u s l e v e l i s m o r e t h a n a d e q u a t e t o m a i n t a i n a s a t i s f a c t o r y B . O . D . r e m o v a l . " S r i n a t h e t a l . a c h i e v e d g r e a t e r t h a n 90% t o t a l p h o s p h o r u s ( T P ) r e m o v a l f r o m a s e w a g e w h i c h i n i t i a l l y c o n t a i n e d 22 p p m T P . E x p l a n a t i o n s f o r t h i s p h e n o m e n o n w e r e n o t s t a t e d . H o w e v e r , t h e s e o b s e r v a t i o n s i n s t i g a t e d r e s e a r c h w h i c h l e d t o t h e d e v e l o p m e n t o f a n u m b e r o f p r o c e s s e s f o r B i o - P r e m o v a l . B i o - P p r o c e s s e s c a n b e d i v i d e d i n t o " m a i n s t r e a m " a n d " s i d e s t r e a m " p r o c e s s e s . I n m a i n s t r e a m p r o c e s s e s , a l l o f t h e p h o s p h o r u s i s r e m o v e d b y t h e b a c t e r i a . S i d e s t r e a m p r o c e s s e s t a k e a d v a n t a g e o f t h e p h o s p h o r u s r e l e a s e e x p e r i e n c e d u n d e r a n a e r o b i c c o n d i t i o n s . T h e y t h e r e f o r e i n v o l v e t h e e x p o s u r e o f t h e b a c t e r i a t o a n a e r o b i c c o n d i t i o n s a n d t h e u s e o f c h e m i c a l s t o p r e c i p i t a t e t h e r e l e a s e d p h o s p h o r u s . R e v i e w s o f t h e v a r i o u s m a i n s t r e a m a n d s i d e s t r e a m p r o c e s s e s w i l l n o w b e p r e s e n t e d . 2 . 2 . 1 M a i n s t r e a m P r o c e s s e s M a i n s t r e a m B i o - P p r o c e s s e s i n c l u d e t h e p a t e n t e d 2 M o d i f i e d B a r d e n p h o , A / 0 a n d A / 0 p r o c e s s e s a n d t h e n o n - p a t e n t e d P h o r e d o x , U C T , m o d i f i e d U C T , V I P , U B C p i l o t p l a n t a n d a n o x i c / a n a e r o b i c / a e r o b i c p r o c e s s e s . S c h e m a t i c d i a g r a m s o f t h e s e p r o c e s s e s a r e p r e s e n t e d i n F i g u r e 2 . 2 . - 18 -A l l o f t h e s e p r o c e s s e s a r e a p p l i c a b l e t o a c t i v a t e d s l u d g e o r e x t e n d e d a e r a t i o n p r o c e s s e s o n l y . H o w e v e r , e n h a n c e d B i o - P r e m o v a l h a s a l s o b e e n a c h i e v e d i n o x i d a t i o n d i t c h e s a n d r o t a t i n g b i o l o g i c a l c o n t a c t o r s ( R B C ' s ) . T h e u s e o f o x i d a t i o n d i t c h e s f o r c o m b i n e d b i o l o g i c a l n i t r o g e n a n d p h o s p h o r u s r e m o v a l h a s b e e n d e v e l o p e d i n D e n m a r k ( P a e p c k e , 1 9 8 5 ) . A l t h o u g h n o t c o n s i d e r e d i n t h i s r e s e a r c h p r o j e c t , t h e p r o c e s s , k n o w n a s t h e B i o d e n i p h o p r o c e s s , c o u l d h a v e a p p l i c a t i o n i n C a n a d i a n o x i d a t i o n d i t c h e s . T h e u s e o f S B R ' s a n d R B C ' s f o r B i o - P r e m o v a l h a s b e e n d e m o n s t r a t e d b y S i m m ( 1 9 8 8 ) . H o w e v e r , s i n c e t h e d e v e l o p m e n t o f t h i s t e c h n o l o g y i s r e l a t i v e l y n e w , i t w i l l n o t b e c o n s i d e r e d f u r t h e r . T h e P h o r e d o x a n d M o d i f i e d B a r d e n p h o p r o c e s s e s w e r e d e v e l o p e d i n S o u t h A f r i c a i n t h e 1 9 7 0 ' s , w h e r e e u t r o p h i c a t i o n o f l a k e s a n d i m p o u n d m e n t s l e d t o t h e i n t r o d u c t i o n o f n i t r o g e n a n d p h o s p h o r u s r e m o v a l s t a n d a r d s f o r m u n i c i p a l w a s t e w a t e r d i s c h a r g e s . B a r n a r d ( 1 9 7 6 ) p r o p o s e d t h e P h o r e d o x p r o c e s s f o r p h o s p h o r u s r e m o v a l o n l y , a n d t h e M o d i f i e d B a r d e n p h o p r o c e s s f o r c o m b i n e d n i t r o g e n a n d p h o s p h o r u s r e m o v a l . T h e P h o r e d o x p r o c e s s i n v o l v e s c r e a t i n g a n a n a e r o b i c / a e r o b i c s e q u e n c e i n t h e b i o r e a c t o r . T h i s i s g e n e r a l l y a c h i e v e d b y s h u t t i n g o f f t h e a i r - 19 -supply to the f r o n t of the r e a c t o r . Mixers are p r o v i d e d i n t h i s a n a erobic zone t o keep the s o l i d s i n suspension. Because the SRT of the Phoredox p r o c e s s i s maintained s u f f i c i e n t l y low to prevent n i t r i f i c a t i o n , p r o t e c t i o n of the a n a e r o b i c zone from n i t r a t e s i s not r e q u i r e d . The M o d i f i e d Bardenpho process p r o v i d e s two anoxic zones (zones which may c o n t a i n n i t r a t e but not oxygen) and a mixed l i q u o r r e c y c l e t o minimize n i t r a t e r e t u r n t o the a n a e r o b i c zone v i a the a c t i v a t e d sludge r e c y c l e . Anoxic zones are not a e r a t e d but are equipped w i t h mixers t o keep the s o l i d s i n suspension. The p r o c e s s operates at a r e l a t i v e l y l o n g sludge age (10-30 days) t o ensure n i t r i f i c a t i o n . A r e a e r a t i o n zone at the end of the b i o r e a c t o r i s p r o v i d e d t o p r e v e n t anaerobic c o n d i t i o n s from o c c u r r i n g i n the secondary c l a r i f i e r . T y p i c a l o p e r a t i n g c o n d i t i o n s are p r e s e n t e d i n Table 2.1. As noted i n T a b l e 2.1, the p r o c e s s r e q u i r e s a v e r y l a r g e r e a c t o r (10 - 23 hour HRT) . T h i s i s due t o the f a c t t h a t i t i s d e s i g n e d t o p r o v i d e complete n i t r i f i c a t i o n , d e n i t r i f i c a t i o n and phosphorus removal. The M o d i f i e d Bardenpho process i s p r o p r i e t a r y and i s l i c e n s e d i n North America by Eimco Process Equipment Company of S a l t Lake C i t y , Utah. Paepcke (1985) r e p o r t s t h a t as of 1985 t h e r e were e i g h t m o d i f i e d Bardenpho p l a n t s o p e r a t i n g or b e i n g Phostrip Modified Bardenpho A / O A / O plus Nitrification Parameter Value Parameter Value Parameter Value Parameter Value A S System F /M , kg T B O D / . . i F /M , kg T B O D / 0.1-0.2 F/M. kg T B O D / 0.2-0.7 F/M, kg T B O O / O.iS-0.25 kg M L V S S / d kg M L V S S / d kg M L V S S / d kg M L V S S / d S R T , d a y s 2 . . i S R T , days 2 10-30 S R T , days 2 2-6 S R T , d a y s 2 4-8 M L S S , mg/l 600 5,000 M L S S . mg/l 2,000-4,000 M L S S , mg/l 2,000-4,000 M L S S , mg/l 3.000-5,000 H R T , rtr3 1-10 H R T , hr3 HRT, hr3 H R T . hr3 Anaerobic 1-2 Anaerobic 0.5-1.5 Anaerobic 0.5-1.5 Anoxic 1 2-4 Aerobic 1-3 Anoxic 0.5-1.0 Nitrification 4-12 Nitrification 3.5-6.0 (Aerobic 1) Anoxic 2 2-4 Aerobic 2 0.5-1.0 Phostrip Stripper Feed. 20-30 Return Sludge, 100 Return Sludge, 25-40 Return Sludge, 20-50 % of inf. flow % of inf. flow % of inf. flow % of inf. flow S D T , hr 5-20 Int Recycle. % of inf. flow 400 Int. Recycle, % of inf. flow 100-300 Sidewater 6.1 • Depth, m Elutriatkxi Flow, 50-100 % of stripper feed flow Underflow, 10-20 % of inf. flow P Release, 0.005-0.02 g P/g V S S Reactor-Clarifier Overflow Rate, 48 m3/m 2/d pH 9-9.5 Lime Dosage, 100-300 mg/l 1 Based on activated sludge system design. 2 Average mass of solids in the system divided by average mass of solids wasted daily. 3 Hydraulic retention time, volume divided by influent flow rale. T A B L E 2.1 - T Y P I C A L O P E R A T I N G C O N D I T I O N S F O R B I O - P P R O C E S S E S (from USEPA, 1987) - 2 1 -c o n s t r u c t e d . O n e o f t h e s e i s t h e K e l o w n a , B . C . p l a n t . T h e m a j o r i t y o f t h e S o u t h A f r i c a n B i o - P p l a n t s a r e o f t h e M o d i f i e d B a r d e n p h o t y p e . N o r e p o r t s o f t h e P h o r e d o x p r o c e s s b e i n g u s e d i n S o u t h A f r i c a h a v e b e e n f o u n d . 2 T h e A / 0 a n d A / 0 p r o c e s s e s a r e p r o p r i e t a r y p r o c e s s e s l i c e n s e d b y A i r P r o d u c t s a n d C h e m i c a l s I n c . o f A l l e n t o w n , P A . 2 T h e A / 0 p r o c e s s i s u s e d f o r p h o s p h o r u s r e m o v a l , w h e r e a s t h e A / 0 p r o c e s s i s u s e d w h e n b o t h n i t r o g e n a n d p h o s p h o r u s r e m o v a l a r e r e q u i r e d . A s s h o w n i n F i g u r e 2 . 2 , t h e A / 0 p r o c e s s i s e s s e n t i a l l y s i m i l a r t o t h e P h o r e d o x p r o c e s s . T h e o n l y s i g n i f i c a n t d i f f e r e n c e b e t w e e n t h e p r o c e s s e s i s t h a t t h e A i r P r o d u c t s p r o c e s s h a s a h i g h e r d e g r e e o f c o m p a r t m e n t a l i z a t i o n i n t h e a n a e r o b i c z o n e . A i r P r o d u c t s a l s o c l a i m t h a t b o t h p r o c e s s e s i m p r o v e s l u d g e s e t t l e a b i l i t y ( A i r P r o d u c t s a n d C h e m i c a l s I n c . , 1 9 8 0 ) . K r i c h t e n e t a l . ( 1 9 8 7 ) r e p o r t s t h a t a s o f 1 9 8 7 , t h e r e w e r e a p p r o x i m a t e l y t w e n t y w a s t e w a t e r t r e a t m e n t p l a n t s u s i n g t h e A / 0 p r o c e s s . T y p i c a l o p e r a t i n g c o n d i t i o n s f o r t h e p r o c e s s e s a r e 2 p r e s e n t e d i n T a b l e 2 . 1 . A s s h o w n t h e r e i n , t h e A / 0 a n d A / 0 p r o c e s s e s o p e r a t e a t c o n s i d e r a b l y s h o r t e r S R T ' s t h a n t h e M o d i f i e d B a r d e n p h o p r o c e s s . I t s h o u l d b e n o t e d t h a t s h o u l d . . . . 2 y e a r - r o u n d n i t r i f i c a t i o n b e r e q u i r e d , t h e A / O p r o c e s s w o u l d h a v e t o b e o p e r a t e d a t a m u c h h i g h e r S R T . - 22 -I n t h e e a r l y 1 9 8 0 ' s r e s e a r c h e r s a t t h e U n i v e r s i t y o f C a p e t o w n d e v e l o p e d a p r o c e s s f o r b i o l o g i c a l n i t r o g e n a n d p h o s p h o r u s r e m o v a l k n o w n a s t h e U C T p r o c e s s . T h e p r o c e s s ( a s i l l u s t r a t e d i n F i g u r e 2 . 2 ) i s d e s i g n e d t o p r e v e n t n i t r a t e s f r o m e n t e r i n g t h e a n a e r o b i c z o n e , a s r e t u r n a c t i v a t e d s l u d g e i s p a s s e d t h r o u g h a n a n o x i c z o n e p r i o r t o b e i n g r e t u r n e d t o t h e a n a e r o b i c z o n e . F o r n i t r o g e n a n d p h o s p h o r u s r e m o v a l , t h e U C T p r o c e s s o p e r a t e s a t a n S R T r o u g h l y e q u i v a l e n t t o t h a t o f t h e M o d i f i e d B a r d e n p h o p r o c e s s . E k a m a e t a l . ( 1 9 8 4 ) p r e s e n t c a l c u l a t i o n s w h i c h s h o w t h a t t h e p r o c e s s c a n r e m o v e p h o s p h o r u s t o l e v e l s b e l o w 1 . 0 m g / L a t l o w e r C O D / T K N r a t i o s t h a n t h e M o d i f i e d B a r d e n p h o p r o c e s s . B e c a u s e t h e p r o c e s s i s r e l a t i v e l y n e w , i t s u s e i n f u l l - s c a l e a p p l i c a t i o n s i s n o t a s w i d e s p r e a d a s t h e u s e o f t h e P h o s t r i p , M o d i f i e d B a r d e n p h o o r A / 0 p r o c e s s e s . P a e p c k e ( 1 9 8 5 ) r e p o r t s t h a t a s o f 1 9 8 5 , t h e r e w a s o n l y o n e f u l l - s c a l e U C T p l a n t i n t h e w o r l d . I t s h o u l d b e n o t e d t h a t a U C T p r o c e s s w i l l b e e m p l o y e d f o r t h e n e w P e n t i c t o n , B . C . w a s t e w a t e r t r e a t m e n t p l a n t s c h e d u l e d f o r o p e r a t i o n i n 1 9 8 9 ( O l d h a m , 1 9 8 8 ) . A n u m b e r o f v a r i a t i o n s t o t h e U C T p r o c e s s h a v e b e e n p r o p o s e d . T h e s e i n c l u d e t h e m o d i f i e d U C T p r o c e s s , t h e V I P p r o c e s s a n d t h e U B C p i l o t p l a n t p r o c e s s . T h e m o d i f i e d U C T p r o c e s s ( E k a m a e t a l . , 1 9 8 4 ) d i v i d e s t h e f i r s t a n o x i c z o n e i n t o t w o z o n e s s u c h t h a t d e n i t r i f i c a t i o n o f t h e R A S a n d m i x e d l i q u o r c a n b e c o n t r o l l e d s e p a r a t e l y . T h e r e d o e s n o t a p p e a r t o h a v e b e e n a n y f u l l - s c a l e u s e o f t h i s p r o c e s s . - 23 -D a i g g e r e t a l . ( 1 9 8 7 ) h a v e t e s t e d a h i g h r a t e U C T - t y p e p r o c e s s k n o w n a s t h e V i r g i n i a I n i t i a t i v e P l a n t ( V I P ) p r o c e s s . T h e p r o c e s s o p e r a t e s a t a s l u d g e a g e o f 4 t o 8 d a y s a n d a t o t a l n o m i n a l h y d r a u l i c r e t e n t i o n t i m e o f a p p r o x i m a t e l y 6 h o u r s . T h i s p r o c e s s , b e c a u s e o f i t s s h o r t s l u d g e a g e , i s e x p e c t e d t o p r o v i d e c o m p l e t e n i t r o g e n r e m o v a l i n w a r m w e a t h e r i n a d d i t i o n t o p h o s p h o r u s r e m o v a l o n a y e a r - r o u n d b a s i s . T h i s i s p a r t i c u l a r l y a p p l i c a b l e t o t h e C a n a d i a n e n v i r o n m e n t w h e r e , i n m a n y p l a c e s , a m m o n i a r e m o v a l i s r e q u i r e d o n l y d u r i n g t h e s u m m e r . I n a d d i t i o n , D a i g g e r e t a l . c l a i m t h a t t h e h i g h r a t e p r o c e s s m a x i m i z e s p h o s p h o r u s r e m o v a l a s i t m a x i m i z e s s l u d g e p r o d u c t i o n . T h e U n i v e r s i t y o f B r i t i s h C o l u m b i a ( U B C ) p i l o t p l a n t p r o c e s s d o e s n o t u t i l i z e t h e a e r o b i c / a n o x i c m i x e d l i q u o r r e c y c l e . I t t h e r e f o r e p e r m i t s a m m o n i a a n d p h o s p h o r u s r e m o v a l , b u t a l l o w s f o r p a r t i a l d e n i t r i f i a t i o n o n l y . A t U B C t h e p r o c e s s c u r r e n t l y o p e r a t e s a t a 2 0 t o 2 5 d a y S R T a n d a n o m i n a l H R T o f 19 h o u r s . T h e s e c o u l d b e r e d u c e d i f i t i s d e s i r e d t o r e m o v e n i t r o g e n o n a s e a s o n a l b a s i s o n l y . A g a i n , t h i s p r o c e s s i s v e r y a p p l i c a b l e i n C a n a d a , w h e r e s e a s o n a l a m m o n i a r e m o v a l s t a n d a r d s a r e t h e n o r m a n d t h e r e q u i r e m e n t f o r c o m p l e t e d e n i t r i f i c a t i o n i s r a r e . A n o t h e r p r o c e s s w h i c h a p p e a r s t o h a v e m e r i t i n t h e C a n a d i a n e n v i r o n m e n t i s t h e a n o x i c / a n a e r o b i c / a e r o b i c p r o c e s s . T h i s p r o c e s s a l l o w s f o r t h e d e n i t r i f i c a t i o n o f t h e R A S w i t h o u t h a v i n g t o i n s t a l l a m i x e d l i q u o r r e c y c l e . T h e r e f o r e , a m m o n i a - 24 -a n d p h o s p h o r u s r e m o v a l c a n b e a c h i e v e d a l o n g w i t h s o m e d e n i t r i f i c a t i o n . T h i s p r o c e s s w o u l d r e q u i r e t h e a d d i t i o n o f a n e x t e r n a l s o u r c e o f V F A ' s s i n c e V F A ' s i n t h e i n f l u e n t s e w a g e w o u l d b e c o n s u m e d b y d e n i t r i f y i n g b a c t e r i a a t t h e f r o n t o f t h e r e a c t o r . T h e a n o x i c / a n a e r o b i c / a e r o b i c p r o c e s s w a s t e s t e d a t t h e p i l o t s c a l e l e v e l a t U B C i n t h e e a r l y 1 9 8 0 ' s ( K o c h , 1 9 8 8 ) . G o o d r e s u l t s w e r e o b t a i n e d w h e n V F A ' s w e r e a d d e d t o t h e a n a e r o b i c z o n e . Q a s i m a n d U d o m s i n r o t ( 1 9 8 7 ) r e p o r t o n t h e s u c c e s s f u l u s e o f t h e p r o c e s s i n l a b s c a l e e x p e r i m e n t s . H o w e v e r , t h e p r o c e s s d o e s n o t a p p e a r t o h a v e b e e n u s e d i n a f u l l - s c a l e t e s t . I t s h o u l d b e n o t e d t h a t b e c a u s e o f t h e s h o r t H R T i n t h e a n a e r o b i c z o n e ( t y p i c a l l y 1 t o 2 h o u r s ) , t h e m a i n s t r e a m B i o - P p r o c e s s e s a r e a l m o s t t o t a l l y d e p e n d e n t u p o n s u f f i c i e n t V F A ' s b e i n g p r e s e n t i n t h e i n f l u e n t w a s t e w a t e r t o p r o m o t e t h e g r o w t h o f B i o - P b a c t e r i a . T h e r e f o r e , s h o u l d i n s u f f i c i e n t q u a n t i t i e s b e p r e s e n t , a n e x t e r n a l V F A s u p p l y w i l l h a v e t o b e a d d e d t o t h e a n a e r o b i c z o n e f o r t h e p r o c e s s e s t o w o r k . 2 . 2 . 2 S i d e s t r e a m P r o c e s s e s S i d e s t r e a m p r o c e s s e s i n c l u d e t h e P h o s t r i p a n d P h o s t r i p I I p r o c e s s e s . S c h e m a t i c d i a g r a m s f o r t h e s e p r o c e s s e s a r e p r e s e n t e d i n F i g u r e 2 . 3 . - 2 5 -PC s c *- WAS STRIPPER LIME SLUDGE PHOSTRIP PROCESS PC SC LIME SLUDGE PHOSTRIP II PROCESS WAS PRE-STRIPPER TANK F I G U R E 2 . 3 - S I D E S T R E A M B I O - P P R O C E S S S C H E M A T I C S - 2 6 -D e v e l o p e d i n t h e U n i t e d S t a t e s i n t h e l a t e 1 9 6 0 ' s a n d e a r l y 1 9 7 0 ' s ( L e v i n e t a l . , 1 9 7 2 ) , t h e P h o s t r i p p r o c e s s w a s t h e f i r s t B i o - P p r o c e s s t o b e b o t h p a t e n t e d a n d u s e d i n a f u l l - s c a l e o p e r a t i o n ( L e v i n e t a l . , 1 9 7 5 ) . T h e p r o c e s s o p e r a t e s l i k e a c o n v e n t i o n a l a c t i v a t e d s l u d g e p l a n t w i t h t h e e x c e p t i o n t h a t a p o r t i o n o f t h e r e t u r n a c t i v a t e d s l u d g e i s r o u t e d t h r o u g h a n a n a e r o b i c s t r i p p e r t a n k . U n d e r t h e a n a e r o b i c c o n d i t i o n s , p h o s p h o r u s i s r e l e a s e d f r o m t h e s l u d g e . R e l e a s e d p h o s p h o r u s i s e l u t r i a t e d f r o m t h e s l u d g e a n d o v e r f l o w s t o a r e a c t o r - c l a r i f i e r w h e r e i t i s t h e n p r e c i p i t a t e d o u t o f s o l u t i o n t h r o u g h l i m e a d d i t i o n . T h e t h i c k e n e d a n a e r o b i c s l u d g e f r o m t h e s t r i p p e r i s r e t u r n e d t o t h e b i o r e a c t o r w h e r e i t , u p o n e x p o s u r e t o a e r o b i c c o n d i t i o n s , t a k e s u p p h o s p h o r u s i n t h e w a s t e w a t e r . T y p i c a l o p e r a t i n g c o n d i t i o n s f o r t h e p r o c e s s a r e p r e s e n t e d i n T a b l e 2 . 1 . T h e p r o c e s s r e l i e s s o l e l y o n t h e s t r i p p e r t a n k t o p r o d u c e V F A ' s f o r P H B s t o r a g e , a s V F A ' s c o n t a i n e d i n t h e i n f l u e n t s e w a g e a r e c o n s u m e d i n t h e b i o r e a c t o r . T h e f a c t t h a t V F A p r o d u c t i o n i n t h e s t r i p p e r i s p r e d o m i n a n t l y b y e n d o g e n o u s d e c a y n e c e s s i t a t e s a l o n g H R T . I n a n e f f o r t t o r e d u c e t h e s i z e o f t h e s t r i p p e r L e v i n a n d D e l i a S a l l a ( 1 9 8 7 ) p r o p o s e d a m o d i f i c a t i o n t o t h e p r o c e s s k n o w n a s t h e P h o s t r i p I I p r o c e s s . I n t h i s m o d i f i c a t i o n , a p r e - s t r i p p e r t a n k i s p r o v i d e d i n w h i c h p r i m a r y e f f l u e n t i s m i x e d w i t h r e t u r n a c t i v a t e d s l u d g e . T h i s p r o v i d e s a s u p p l y o f V F A ' s a n d / o r a s u p p l y o f m o r e e a s i l y f e r m e n t a b l e c a r b o n c o m p o u n d s , t o t h e s t r i p p e r . L e v i n a n d D e l i a S a l l a c l a i m t h a t t h i s m o d i f i c a t i o n r e d u c e s t h e v o l u m e o f t h e s t r i p p e r t a n k b y a s m u c h a s 50%. - 2 7 -T h e p r o c e s s c a n a l s o b e m o d i f i e d t o f a c i l i t a t e i n c o r p o r a t i o n i n t o a n i t r i f i c a t i o n p l a n t . T h e s t r i p p e r t a n k c a n e i t h e r b e s i z e d t o a c c o m m o d a t e d e n i t r i f i c a t i o n , o r a n a n o x i c d e n i t r i f i c a t i o n b a s i n c a n b e p l a c e d u p s t r e a m o f t h e s t r i p p e r t a n k . P h o s t r i p i s a p r o p r i e t a r y p r o c e s s a n d i s l i c e n s e d b y B i o s p h e r i c s I n c . o f R o c k v i l l e , M D . L e v i n a n d D e l i a S a l l a ( 1 9 8 7 ) r e p o r t t h a t a s o f 1 9 8 7 , f i f t e e n m u n i c i p a l P h o s t r i p p l a n t s h a v e b e e n o r a r e n o w i n c o n s t r u c t i o n t h r o u g h o u t t h e w o r l d , a n d t h a t m o r e t h a n f i f t e e n p i l o t p l a n t s h a v e b e e n o p e r a t e d . T h e y c l a i m t h a t a l l o f t h e s e i n s t a l l a t i o n s h a v e c o n s i s t e n t l y b e e n a b l e t o a c h i e v e e f f l u e n t s c o n t a i n i n g 1 . 0 m g / L T P o r l e s s . 2 . 2 . 3 K i n e t i c M o d e l l i n g A n u m b e r o f r e s e a r c h e r s h a v e a t t e m p t e d t o m o d e l t h e k i n e t i c s o f t h e B i o - P r e m o v a l m e c h a n i s m , s u c h t h a t p r e d i c t i o n s o f p h o s p h o r u s r e m o v a l c a n b e m a d e f o r t h e v a r i o u s B i o - P p r o c e s s e s . H o n g e t a l . ( 1 9 8 1 ) d e v e l o p e d s e m i - e m p i r i c a l m o d e l s f o r t h e A / O p r o c e s s t o d e s c r i b e p h o s p h o r u s r e l e a s e i n t h e a n a e r o b i c z o n e a n d p h o s p h o r u s u p t a k e i n t h e a e r o b i c z o n e . T h e m o d e l s a r e e s s e n t i a l l y b a s e d o n t h e d r i v i n g f o r c e c o n c e p t w h i c h r e l a t e s p h o s p h o r u s r e l e a s e a n d u p t a k e r a t e s t o t h e d i f f e r e n c e b e t w e e n - 28 -s o l u b l e phosphate i n the wastewater and s t o r e d polyphosphate i n the b a c t e r i a l mass. Hong e t a l . r e p o r t the s u c c e s s f u l a p p l i c a t i o n of t h i s model t o the Largo, F l o r i d a A/0 p l a n t . Equations developed are as f o l l o w s : ( i ) Anaerobic C o n d i t i o n s dPS = k, ( - 1 ^ - PS )X + h 0 R. " d t 1 X 2 • ( i i ) A e r o b i c C o n d i t i o n s = k 2 X PS ( 1 + 1 - / p I / p * ^ s s o l u b l e phosphate (mg/L) b a c t e r i a l s t o r e d polyphosphate (mg/L) maximum st o r a g e of polyphosphate (mg/L) r a t e of b i o l o g i c a l a b s o r p t i o n of BOD (mg/L-hr) a c t i v e biomass (mg/L) p r o p o r t i o n a l i t y c o n s t a n t s (mg/L and di m e n s i o n l e s s r e s p e c t i v e l y ) r a t e c o n s t a n t s (L/mg-hr) s a t u r a t i o n c o n s t a n t ( d i m e n s i o n l e s s ) I t appears t h a t t h i s model assumes t h a t s u f f i c i e n t VFA's are presen t i n the an a e r o b i c zone t o promote Bio-P b a c t e r i a growth, and t h a t s u f f i c i e n t BOD i s p r e s e n t t o accommodate phosphorus removal t o the l e v e l s p r e d i c t e d . T h i s , combined w i t h the d i f f i c u l t y i n p r o v i d i n g meaningful v a l u e s f o r the c o n s t a n t s i n the equ a t i o n s , make the use of t h i s model r e l a t i v e l y l i m i t e d . dPS d t where PS PI P* ^OD X = h l ' h 2 s - 2 9 -S i e b r i t z , e t a l . ( 1 9 8 3 ) p r e s e n t e d a s e m i - e m p i r i c a l m o d e l w h i c h c o u l d b e u s e d t o p r e d i c t t h e a m o u n t o f p h o s p h o r u s r e m o v a l f o r v a r i o u s p r o c e s s c o n f i g u r a t i o n s a n d w a s t e w a t e r c o m p o s i t i o n s . I t w a s b a s e d o n t h e a s s u m p t i o n t h a t a m i n i m u m o f 2 5 m g / L o f " r e a d i l y b i o d e g r a d a b l e " C O D i s r e q u i r e d i n t h e a n a e r o b i c z o n e t o p r o m o t e t h e g r o w t h o f B i o - P b a c t e r i a a n d , h e n c e , t r i g g e r t h e B i o - P r e m o v a l p r o c e s s . T h e a m o u n t o f r e a d i l y b i o d e g r a d a b l e C O D t h e n d e f i n e s a m e a s u r e o f t h e a b i l i t y o f t h e p r o c e s s t o r e m o v e p h o s p h o r u s . T h i s i s c a l l e d t h e " e x c e s s p h o s p h o r u s r e m o v a l p r o p e n s i t y f a c t o r " a n d i s c a l c u l a t e d a s f o l l o w s : P _ = ( S . - 2 5 ) f f v b s a ' x a W h e r e P f = e x c e s s p h o s p h o r u s r e m o v a l p r o p e n s i t y f a c t o r S. = r e a d i l y b i o d e g r a d a b l e s o l u b l e C O D i n t h e a n a e r o b i c z o n e ( m g / L ) f = a n a e r o b i c s l u d g e m a s s f r a c t i o n Xcl T h e p r o p e n s i t y f a c t o r i s t h e n u s e d t o d e t e r m i n e t h e a m o u n t o f e n h a n c e d B i o - P r e m o v a l a t t a i n a b l e . S i e b r i t z e t a l . d e f i n e t h i s i n t e r m s o f a c o e f f i c i e n t c a l l e d t h e " c o e f f i c i e n t o f e x c e s s p h o s p h o r u s r e m o v a l " . T h i s i s c a l c u l a t e d u s i n g t h e f o l l o w i n g e m p e r i c a l l y d e r i v e d e q u a t i o n : Y = 0 . 3 5 - 0 . 2 9 e < - ° ' 2 4 2 P f > W h e r e X = c o e f f i c i e n t o f e x c e s s p h o s p h o r u s r e m o v a l (mg P / m g V S S ) - 3 0 -T h e a m o u n t o f p h o s p h o r u s r e m o v a l c a n t h e n b e c a l c u l a t e d b y m u l t i p l y i n g t h e c o e f f i c i e n t o f e x c e s s p h o s p h o r u s r e m o v a l b y t h e w e i g h t o f b i o m a s s w a s t e d . I t s h o u l d b e n o t e d t h a t t h i s m e t h o d a s s u m e s t h a t n o n i t r a t e s o r DO a r e p r e s e n t i n t h e a n a e r o b i c z o n e . I f t h i s i s n o t t h e c a s e , p r o p o r t i o n a t e l y m o r e r e a d i l y b i o d e g r a d a b l e C O D i s r e q u i r e d t o t r i g g e r t h e B i o - P r e m o v a l m e c h a n i s m . S i e b r i t z e t a l . p r e s e n t a m e t h o d b y w h i c h t h i s c a n b e c a l c u l a t e d . T h i s m o d e l h o w e v e r , d o e s n o t a p p e a r t o b e a p p l i c a b l e t o C a n a d i a n t r e a t m e n t p l a n t s . E k a m a e t a l . ( 1 9 8 4 ) r e c o m m e n d e d t h a t t h e m o d e l s h o u l d n o t b e u s e d f o r p l a n t s h a v i n g S R T ' s l e s s t h a n 14 d a y s . I n a d d i t i o n , B a r n a r d e t a l . ( 1 9 8 5 ) r e p o r t s t h a t t h e m o d e l , w h e n a p p l i e d t o t h e K e l o w n a p l a n t , p r e d i c t e d t h a t B i o - P r e m o v a l w o u l d n o t o c c u r . R e c e n t w o r k o n t h e d e v e l o p m e n t o f k i n e t i c m o d e l s h a s b e e n r e p o r t e d b y T s u n o e t a l . ( 1 9 8 7 ) a n d W e n t z e l l e t a l . ( 1 9 8 7 ) . T s u n o e t a l . d e v e l o p e d a m o d e l w h i c h s i m u l a t e d p h o s p h o r u s r e l e a s e a n d u p t a k e , T O C r e m o v a l a n d c h a n g e s i n i n t r a c e l l u l a r c a r b o h y d r a t e a n d P H B . W e n t z e l l e t a l . d e v e l o p e d a m o d e l t o d e s c r i b e t h e s t o i c h i o m e t r y a n d k i n e t i c s o f t h e a n a e r o b i c / a e r o b i c b e h a v i o u r o f B i o - P b a c t e r i a . N e i t h e r m o d e l w o u l d a p p e a r s u f f i c i e n t l y d e v e l o p e d f o r f u l l - s c a l e a p p l i c a t i o n h o w e v e r . - 3 1 -2 . 3 P r e v i o u s A s s e s s m e n t s o f B i o - P T e c h n o l o g y 2 . 3 . 1 T e c h n i c a l A s s e s s m e n t s O v e r t h e p a s t f i v e y e a r s , t h e r e s u l t s o f f i v e i n d e p e n d e n t s t u d i e s w h i c h r e v i e w e d t h e t e c h n i c a l c a p a b i l i t i e s o f t h e v a r i o u s B i o - P r e m o v a l p r o c e s s e s , h a v e b e e n p u b l i s h e d . W a l s h e t a l . ( 1 9 8 3 ) s u m m a r i z e t h e r e s u l t s o f a n i n v e s t i g a t i o n c a r r i e d o u t f o r t h e W a s h i n g t o n S u b u r b a n S a n i t a r y C o m m i s s i o n . R o y F . W e s t o n I n c . ( 1 9 8 5 ) a n d T e t r e a u l t e t a l . ( 1 9 8 5 ) p r e s e n t t h e r e s u l t s o f s t u d i e s p r e p a r e d f o r t h e U S E P A . E v a n s a n d C r a w f o r d ( 1 9 8 5 ) c o m m e n t o n t h e p o t e n t i a l f o r t h e u s e o f B i o - P r e m o v a l i n C a n a d a . C a n v i r o e t a l . ( 1 9 8 6 ) p r e s e n t t h e r e s u l t s o f a n e v a l u a t i o n c a r r i e d o u t f o r E n v i r o n m e n t C a n a d a . T h e c o n c l u s i o n s o f t h e s e s t u d i e s a r e s u m m a r i z e d i n T a b l e 2 . 2 . T h e g e n e r a l c o n s e n s u s a p p e a r s t o b e t h a t e f f l u e n t u n f i l t e r e d T P c o n c e n t r a t i o n s o f l e s s t h a n 2 . 0 m g / L c a n b e e a s i l y a c h i e v e d w i t h m o s t B i o - P p r o c e s s e s . T e t r e a u l t e t a l . ( 1 9 8 5 ) s u g g e s t t h a t c o n c e n t r a t i o n s o f l e s s t h a n 1 . 0 m g / L c a n b e a c h i e v e d b y a l l p r o c e s s e s . W a l s h e t a l . ( 1 9 8 3 ) a n d C a n v i r o e t a l . ( 1 9 8 6 ) i n d i c a t e t h a t e f f l u e n t f i l t r a t i o n o r s u p p l e m e n t a l c h e m i c a l a d d i t i o n i s r e q u i r e d t o a c h i e v e l e s s t h a n 1 . 0 m g / L f o r t h e M o d i f i e d B a r d e n p h o , A / 0 a n d U C T p r o c e s s e s . - 32 -T h e a b o v e m e n t i o n e d s t u d i e s g e n e r a l l y r e c o g n i z e t h a t t h e c h a r a c t e r i s t i c s o f t h e i n f l u e n t s e w a g e a r e c r i t i c a l t o t h e p e r f o r m a n c e o f t h e B i o - P p r o c e s s . E v a n s a n d C r a w f o r d ( 1 9 8 5 ) p r e s e n t s p e c i f i c c a r b o n t o p h o s p h o r u s a n d c a r b o n t o n i t r o g e n r a t i o s r e q u i r e d t o e n s u r e p h o s p h o r u s r e m o v a l t o l e s s t h a n 1 . 0 m g / L T P . T h e s e a r e s u m m a r i z e d i n T a b l e 2 . 3 . T h e y a l s o n o t e t h e i m p o r t a n c e o f s u f f i c i e n t c o n c e n t r a t i o n s o f s o l u b l e c a r b o n s u b s t r a t e s ( s u c h a s V F A ' s ) i n t h e a n a e r o b i c z o n e . T h i s i s g e n e r a l l y i g n o r e d i n t h e o t h e r s t u d i e s . S T U D Y P H O S T R I P W a l s h e t a l . ( 1 9 8 3 ) - F i l t e r e d < 1 . 0 - U n f i l t e r e d < 1 . 5 R o y F . W e s t o n , I n c . ( 1 9 8 5 ) < 1 . 0 T e t r e a u l t e t a l . ( 1 9 8 5 ) < 1 . 0 C a n v i r o e t a l . ( 1 9 8 6 ) - F i l t e r e d < 0 . 3 - U n f i l t e r e d < 1 . 0 - U n f i l t e r e d + C h e m i c a l A d d i t i o n N . R . - F i l t e r e d + C h e m i c a l A d d i t i o n N . R . A C H I E V A B L E E F F L U E N T T P ( m a / L - P ) M O D I F I E D B A R D E N P H O A / 0 A 2 / 0 < 1 . 0 < 1 . 0 < 1 . 5 < 1 . 0 < 2 . 0 < 3 . 0 < 2 . 0 < 2 . 0 < 2 . 0 < 1 . 0 < 1 . 0 < 1 . 0 < 1 . 0 < 1 . 0 N . R . < 2 . 0 < 2 . 0 N . R . < 1 . 0 < 1 . 0 N . R . < 0 . 3 < 0 . 3 N . R . R . - N o t r e p o r t e d T A B L E 2.2 - S U M M A R Y O F P E R F O R M A N C E A S S E S S M E N T S O F B I O - P P R O C E S S E S L I M I T O N P A R A M E T E R P A R A M E T E R P H O S T R I P M O D I F I E D B A R D E N P H O A / O 1 . C O D : P 2 . B O D 5 : P 3 . C O D : T K N 4 . B O D g : T K N >28 >18 > 7 . 1 > 4 . 3 > 4 0 > 2 5 > 8 . 3 > 5 . 0 N / A > 2 5 N / A > 6 . 7 N / A - N o t a v a i l a b l e T A B L E 2.3 - S E W A G E C H A R A C T E R I S T I C S R E Q U I R E D F O R B I O - P R E M O V A L T O L E S S T H A N 1.0 mg / L T P ( f r o m E v a n s a n d C r a w f o r d , 1 9 8 5 ) - 3 5 -2 . 3 . 2 E c o n o m i c A s s e s s m e n t s T h e m o s t r e c e n t d e t a i l e d a s s e s s m e n t o f t h e c o s t e f f e c t i v e n e s s o f B i o - P t e c h n o l o g y w a s c a r r i e d o u t b y C a n v i r o e t a l . ( 1 9 8 6 ) . T h e y c o n c l u d e d t h a t t h e p o t e n t i a l f o r t h e u s e o f B i o - P w a s r e l a t i v e l y l i m i t e d i n C a n a d a a n d s u g g e s t t h a t t h e r e a r e p r e s e n t l y l e s s t h a n 1 5 p l a n t s i n t h e c o u n t r y t h a t a r e c a n d i d a t e s f o r B i o - P r e t r o f i t s . T h e y n o t e , h o w e v e r , t h a t t h e f o l l o w i n g c i r c u m s t a n c e s w o u l d m a k e B i o - P r e m o v a l m o r e a t t r a c t i v e : i ) i m p o s i t i o n o f t o t a l p h o s p h o r u s e f f l u e n t l i m i t s o f l e s s t h a n 0 . 5 m g / L , i i ) i m p o s i t i o n o f n i t r o g e n r e m o v a l s t a n d a r d s , i i ) m a j o r i n c r e a s e s i n t h e p r i c e o f f e r r i c c h l o r i d e i n O n t a r i o , i v ) i n c r e a s e d c o n f i d e n c e i n t h e c a p a b i l i t y o f B i o - P r e m o v a l t o a c h i e v e e f f l u e n t t o t a l p h o s p h o r u s l i m i t s o f l e s s t h a n 1 . 0 m g / L , v ) c a p i t a l f u n d i n g a s s i s t a n c e . I n s p i t e o f t h e s e c o n c l u s i o n s , C a n v i r o e t a l . d i d p r e s e n t r e s u l t s o f a n e c o n o m i c a n a l y s i s w h i c h s h o w e d t h e e c o n o m i c a d v a n t a g e s o f t h e B i o - P t e c h n o l o g y . W h e n c o m p a r e d o n a t o t a l a n n u a l c o s t b a s i s ( w h i c h i n c l u d e s t h e a m o r t i z a t i o n o f i n c r e m e n t a l c a p i t a l c o s t s ) t h e A / O p r o c e s s w a s f o u n d t o b e e c o n o m i c a l l y s u p e r i o r t o c h e m i c a l r e m o v a l p r o c e s s e s f o r t h e f o l l o w i n g c a s e s : - 3 6 -i ) N e w s e c o n d a r y p l a n t s h a v i n g e f f l u e n t t o t a l p h o s p h o r u s s t a n d a r d s o f 1 . 0 m g / L a n d 0 . 3 m g / L . i i ) R e t r o f i t s o f c o n v e n t i o n a l a c t i v a t e d s l u d g e p l a n t s h a v i n g 3 f l o w s g r e a t e r t h a n 1 3 , 6 0 0 m / d a n d e f f l u e n t t o t a l p h o s p h o r u s s t a n d a r d s o f 1 . 0 m g / L a n d 0 . 3 m g / L . T h e M o d i f i e d B a r d e n p h o , U C T a n d P h o s t r i p p r o c e s s e s w e r e a l s o c o m p a r e d a g a i n s t c h e m i c a l r e m o v a l p r o c e s s e s a n d w e r e n o t f o u n d t o b e e c o n o m i c . T h i s i s u n d e r s t a n d a b l e f o r t h e M o d i f i e d B a r d e n p h o a n d U C T p r o c e s s e s s i n c e t h e y a r e c o m b i n e d n i t r o g e n a n d p h o s p h o r u s r e m o v a l t e c h n o l o g i e s , a n d w e r e b e i n g c o m p a r e d a g a i n s t a p h o s p h o r u s - o n l y r e m o v a l t e c h n o l o g y . S i n c e c o m b i n e d n i t r o g e n a n d p h o s p h o r u s r e m o v a l r e q u i r e s a s i g n i f i c a n t l y l a r g e r a e r a t i o n b a s i s t h a n f o r p h o s p h o r u s r e m o v a l a l o n e , t h e a n a l y s i s p r e s e n t e d b y C a n v i r o e t a l . r e f l e c t s t h e d i f f e r e n c e i n c a p i t a l c o s t b e t w e e n t h e t w o a e r a t i o n b a s i n s . A m o r e v a l i d a n a l y s i s w o u l d h a v e b e e n t o c o m p a r e t h e M o d i f i e d B a r d e n p h o a n d U C T p r o c e s s e s a g a i n s t a n i t r i f i c a t i o n / d e n i t r i f i c a t i o n p l a n t h a v i n g c h e m i c a l p h o s p h o r u s r e m o v a l . I t s h o u l d a l s o b e n o t e d t h a t C a n v i r o e t a l . b a s e d t h e i r c o n c l u s i o n s o n h y p o t h e t i c a l t r e a t m e n t p l a n t s a n d h e n c e , d i d n o t c o n s i d e r r e g i o n a l v a r i a t i o n s i n s e w a g e c h a r a c t e r i s t i c s , s l u d g e h a n d l i n g p r a c t i c e s a n d c h e m i c a l c o s t s . - 3 7 -R o y F . W e s t o n , I n c . ( 1 9 8 5 ) a l s o s t u d i e d t h e e c o n o m i c s o f B i o - P r e m o v a l v e r s u s c h e m i c a l r e m o v a l f o r h y p o t h e t i c a l n e w t r e a t m e n t p l a n t s o f d i f f e r e n t s i z e s a n d h a v i n g d i f f e r e n t p h o s p h o r u s a n d n i t r o g e n r e m o v a l s t a n d a r d s . T h e P h o s t r i p , M o d i f i e d B a r d e n p h o a n d A / 0 p r o c e s s e s w e r e c o n s i d e r e d i n t h i s s t u d y . T h e r e s u l t s o f t h e a n a l y s i s ( a s p r e s e n t e d i n T a b l e 2 . 4 ) s h o w e d t h a t B i o - P r e m o v a l w a s e c o n o m i c a l l y s u p e r i o r o n a p r e s e n t w o r t h b a s i s i n a l l c a s e s w i t h t h e e x c e p t i o n o f p l a n t s h a v i n g 3 c a p a c i t i e s l e s s t h a n 1 , 8 9 2 m / d a n d e f f l u e n t t o t a l p h o s p h o r u s s t a n d a r d s l e s s t h a n 1 . 0 m g / L . I n a l l c a s e s i n v o l v i n g n i t r o g e n a n d p h o s p h o r u s r e m o v a l , B i o - P w a s d e e m e d t o b e e c o n o m i c a l l y s u p e r i o r . P L A N T T H R O U G H P U T ( m 3 / d ) E F F L U E N T S T A N D A R D S 1 . 8 9 2 1 8 . 9 2 5 1 8 9 . 2 5 0 1 . T P < 1 . 0 m g / L - P C h e m i c a l P h o s t r i p P h o s t r i p 2 . T P < 2 . 0 m g / L - P A / 0 A / 0 A / 0 3 . T P < 2 . 0 m g / L - P N H 3 < 1 . 0 m g / L - N A / 0 A / 0 A / 0 4 . T P < 2 . 0 m g / L - P N H 3 < 3 . 0 m g / L - N M o d i f i e d B a r d e n p h o M o d i f i e d B a r d e n p h o M o d i f i e d B a r d e n p h o N o t e : P r o c e s s e s l i s t e d r e p r e s e n t t h e e c o n o m i c a l l y s u p e r i o r p r o c e s s . T A B L E 2 . 4 - S U M M A R Y O F U S E P A S P O N S O R E D S T U D Y O N B I O - P R E M O V A L E C O N O M I C S - 38 -E v a n s a n d C r a w f o r d ( 1 9 8 5 ) p r e s e n t a n e c o n o m i c a n a l y s i s f o r a h y p o t h e t i c a l 4 9 , 0 0 0 m / d p l a n t l o c a t e d i n w e s t e r n C a n a d a . I n t h i s a n a l y s i s t h e y c o m p a r e a P h o r e d o x p r o c e s s ( s i m i l a r t o t h e A / 0 p r o c e s s ) a g a i n s t a c h e m i c a l r e m o v a l p r o c e s s u s i n g a l u m a s t h e p r e c i p i t a n t . T h e y c o n c l u d e t h a t t h e i n c r e m e n t a l c a p i t a l c o s t o f i n s t a l l i n g t h e P h o r e d o x p r o c e s s i s a p p r o x i m a t e l y $ 2 , 1 0 0 , 0 0 0 . A n n u a l s a v i n g s o f $ 1 9 2 , 0 0 0 . w e r e c a l c u l a t e d f o r t h e u s e o f t h e B i o - P t e c h n o l o g y o v e r c h e m i c a l r e m o v a l . I t s h o u l d b e n o t e d t h a t t h e l a r g e d i f f e r e n c e i n c a p i t a l c o s t b e t w e e n t h e t w o o p t i o n s w a s b a s e d o n t h e a u t h o r ' s a s s u m p t i o n t h a t s e c o n d a r y e f f l u e n t f i l t r a t i o n w a s r e q u i r e d t o a c h i e v e t h e e f f l u e n t p h o s p h o r u s s t a n d a r d o f 1 . 0 m g / L f o r t h e P h o r e d o x p r o c e s s . S h i v j i ( 1 9 8 7 ) p r e p a r e d a n e c o n o m i c a n a l y s i s f o r t h e E d m o n t o n G o l d B a r W a s t e w a t e r T r e a t m e n t P l a n t . F r o m t h i s a n a l y s i s i t w a s c o n c l u d e d t h a t s h o u l d t h e p l a n t b e r e q u i r e d t o r e m o v e p h o s p h o r u s , b o t h t h e A / O a n d P h o s t r i p p r o c e s s e s o f f e r e d s i g n i f i c a n t s a v i n g s o v e r c h e m i c a l p h o s p h o r u s r e m o v a l . A s s u m i n g a 2 0 y e a r a m o r t i z a t i o n p e r i o d a n d a 10% r a t e o f r e t u r n , t h e t o t a l a n n u a l c o s t s o f t h e v a r i o u s o p t i o n s w e r e a s f o l l o w s : R e m o v a l P r o c e s s T o t a l A n n u a l C o s t ( $ ) i ) C h e m i c a l ( L i q u i d a l u m 3 , 3 7 4 , 4 6 7 t o a e r a t i o n b a s i n s ) i i ) P h o s t r i p 2 , 1 7 5 , 4 3 5 i i i ) A / O 1 , 8 3 9 , 5 2 7 - 3 9 -I t s h o u l d b e n o t e d h o w e v e r , t h a t i n h i s a n a l y s i s , S h i v j i m a d e n o a l l o w a n c e s f o r e i t h e r V F A p r o d u c t i o n t h r o u g h p r i m a r y s l u d g e f e r m e n t a t i o n , o r a n a e r o b i c d i g e s t o r s u p e r n a t a n t t r e a t m e n t . A n u m b e r o f r e f e r e n c e s p r e s e n t a n a l y s e s s h o w i n g t h e e c o n o m i c a d v a n t a g e s o f t h e P h o s t r i p p r o c e s s o v e r b o t h c h e m i c a l r e m o v a l a n d o t h e r B i o - P p r o c e s s e s . L e v i n a n d D e l i a S a l l a ( 1 9 8 7 ) p r e s e n t e d d a t a ( s e e T a b l e 2 . 5 ) w h i c h i n d i c a t e s t h e c a p i t a l c o s t o f i n s t a l l i n g t h e P h o s t r i p I I p r o c e s s f o r v a r i o u s p l a n t f l o w s , a n d t h e a s s o c i a t e d s a v i n g s i n o p e r a t i n g c o s t s . P e i r a n o e t a l . ( 1 9 8 3 ) e s t i m a t e s t h a t t h e i n c r e m e n t a l c a p i t a l c o s t r e q u i r e d t o 3 r e t r o f i t t h e 1 5 2 , 0 0 0 m / d R e n o - S p a r k s W a t e r P o l l u t i o n C o n t r o l P l a n t i n N e v a d a , t o t h e P h o s t r i p p r o c e s s i s $ 4 , 9 4 0 , 0 0 0 . S a v i n g s i n o p e r a t i n g c o s t s w e r e e s t i m a t e d t o b e $ 1 , 3 0 0 , 0 0 0 / y e a r . C a p i t a l c o s t s t o r e t r o f i t t o o t h e r B i o - P . p r o c e s s e s w e r e e s t i m a t e d t o b e $ 5 , 9 2 0 , 0 0 0 . I t s h o u l d b e n o t e d t h a t s u p p o r t i n g d a t a f o r t h e a b o v e e s t i m a t e s i s n o t p r o v i d e d . - 4 0 -_ P H O S T R I P I I A N N U A L C O S T S f S X 10 ) C A P I T A L P L A N T F L O W C H E M I C A L C O S T ( M U S G D i A D D I T I O N P H O S T R I P I I S A V I N G S ( S X 1 0 ) 5 6 2 4 4 1 4 2 0 9 1 , 2 0 0 1 0 1 , 2 4 8 8 2 9 4 1 9 1 , 7 6 0 2 0 2 , 4 9 5 1 , 6 5 7 8 3 8 2 , 5 4 0 3 0 3 , 7 4 3 2 , 4 8 6 1 , 2 5 7 3 , 2 7 0 5 0 6 , 2 3 8 4 , 1 4 4 2 , 0 9 5 4 , 6 8 0 T A B L E 2 . 5 - P H O S T R I P I I S A V I N G S A N D C O S T S ( f r o m L e v i n a n d D e l i a S a l l a , 1 9 8 7 ) - 4 1 -L e v i n e t a l . ( 1 9 7 5 ) c o m p a r e d t h e t o t a l a n n u a l c o s t s o f t h e P h o s t r i p p r o c e s s t o t h o s e a s s o c i a t e d w i t h m i n e r a l a d d i t i o n a n d t w o - s t a g e l i m e p h o s p h o r u s r e m o v a l . A s s u m i n g a 2 5 y e a r c a p i t a l c o s t a m o r t i z a t i o n p e r i o d a n d a 6% r a t e o f r e t u r n , t h e r e s u l t s ( s h o w n b e l o w ) s u g g e s t d e f i n i t e e c o n o m i c a d v a n t a g e s f o r t h e P h o s t r i p p r o c e s s . T O T A L A N N U A L C O S T ( 1 9 7 3 U S S / M G 1 P L A N T F L O W T W O - S T A G E M I N E R A L ( M U S G D ) P H O S T R I P L I M E A D D I T I O N 1 0 2 9 . 4 0 1 2 9 . 7 5 5 4 . 7 5 5 0 2 9 . 1 5 8 3 . 0 0 5 2 . 3 5 D e a k y n e e t a l . ( 1 9 8 4 ) r e p o r t s t h a t W h i t m a n , R e q u a r d t a n d A s s o c i a t e s ( 1 9 8 2 ) d e t e r m i n e d t h a t t h e p r e s e n t w o r t h o f r e t r o f i t t i n g t h e 7 0 M U S G D P a t a p s c o P l a n t a t B a l t i m o r e , MD u s i n g t h e A / O p r o c e s s , w a s a p p r o x i m a t e l y 5 0 p e r c e n t l e s s t h a n t h e p r e s e n t w o r t h o f a c h e m i c a l r e m o v a l r e t r o f i t . H o w e v e r , s u p p o r t i n g d o c u m e n t a t i o n w a s n o t a t t a i n a b l e . B a s e d o n t h e a b o v e i n f o r m a t i o n , i t i s e v i d e n t t h a t t h e r e m a y b e e c o n o m i c a d v a n t a g e s a s s o c i a t e d w i t h B i o - P t e c h n o l o g y . - 42 -3.0 S T U D Y M E T H O D O L O G Y 3 . 1 G e n e r a l I n o r d e r t o a s s e s s t h e p o t e n t i a l f o r B i o - P r e m o v a l i n C a n a d a , i t w a s d e c i d e d t o c a r r y o u t c o m p a r a t i v e s t u d i e s o n a r e p r e s e n t a t i v e c r o s s s e c t i o n o f C a n a d i a n w a s t e w a t e r t r e a t m e n t p l a n t s . T h i s i n v o l v e d p r e p a r i n g B i o - P r e t r o f i t d e s i g n s f o r n i n e p l a n t s a n d c o m p a r i n g t h e c a p i t a l a n d o p e r a t i n g c o s t s a s s o c i a t e d w i t h t h e s e d e s i g n s , a g a i n s t t h e c a p i t a l a n d o p e r a t i n g c o s t s f o r e q u i v a l e n t c h e m i c a l p h o s p h o r u s r e m o v a l t e c h n o l o g y . T h e i n c r e m e n t a l c a p i t a l c o s t o f i n s t a l l i n g a B i o - P p r o c e s s , o v e r a c h e m i c a l r e m o v a l p r o c e s s , w a s c a l c u l a t e d a n d c o m p a r e d a g a i n s t t h e i n c r e m e n t a l o p e r a t i n g c o s t s a v i n g s o f a B i o - P o p e r a t i o n v e r s u s a c h e m i c a l r e m o v a l o p e r a t i o n . F r o m t h e s e i n t e r n a l c o s t s , i n c r e m e n t a l r a t e s o f r e t u r n ( I R R ' s ) f o r t h e c a p i t a l r e q u i r e d t o i n s t a l l t h e B i o - P p r o c e s s e s , w e r e c a l c u l a t e d . U s i n g t h e s e r a t e s o f r e t u r n , a n o v e r a l l a s s e s s m e n t o f t h e p o t e n t i a l o f B i o - P r e m o v a l w a s m a d e . T h e s t u d y w a s c a r r i e d o u t i n t h e f o l l o w i n g n i n e s t a g e s : i ) s e l e c t t r e a t m e n t p l a n t s f o r s t u d y , i i ) o b t a i n p l a n t d e s i g n a n d o p e r a t i n g d a t a , i i i ) p r e p a r e p r e l i m i n a r y B i o - P r e t r o f i t d e s i g n s , - 4 3 -i v ) m e e t w i t h p l a n t s t a f f t o r e v i e w B i o - P d e s i g n s , v ) r e v i s e B i o - P d e s i g n s a s r e q u i r e d , v i ) p r e p a r e i n c r e m e n t a l m a t e r i a l t a k e - o f f s ( M T O ' s ) , v i i ) e s t i m a t e i n c r e m e n t a l c a p i t a l a n d o p e r a t i n g c o s t s , v i i i ) p r e p a r e e c o n o m i c a n a l y s e s i x ) p r e p a r e o v e r a l l a s s e s s m e n t a n d d e v e l o p c o n c l u s i o n s a n d r e c o m m e n d a t i o n s . A s p r e v i o u s l y m e n t i o n e d , n i n e w a s t e w a t e r t r e a t m e n t p l a n t s w e r e s t u d i e d . T h e b a s i s f o r t h e s e l e c t i o n o f t h e s e p l a n t s i s d e t a i l e d i n S e c t i o n 3 . 2 ; h o w e v e r , i n g e n e r a l t e r m s , p l a n t s w e r e s e l e c t e d t o e v a l u a t e t h e i m p a c t s o f s e w a g e c h a r a c t e r i s t i c s , n u t r i e n t r e m o v a l s t a n d a r d s , r e g i o n a l d i f f e r e n c e s i n c h e m i c a l c o s t s , p r o c e s s t y p e s , a n d n e w v e r s u s r e t r o f i t p r o j e c t s o n t h e e c o n o m i c s o f B i o - P r e m o v a l . A f t e r s e l e c t i n g t h e p l a n t s t o b e s t u d i e d , d e s i g n a n d o p e r a t i n g d a t a w a s r e q u e s t e d f r o m e a c h p l a n t . T h e f o l l o w i n g i n f o r m a t i o n ( w h e r e a p p l i c a b l e ) w a s r e q u e s t e d : i ) P r o c e s s f l o w d i a g r a m s a n d l a y o u t d r a w i n g s . i i ) D e t a i l e d b i o r e a c t o r a n d s e c o n d a r y c l a r i f i e r d r a w i n g s . i i i ) A e r a t i o n s y s t e m s c h e m a t i c s a n d b l o w e r / a e r a t o r p e r f o r m a n c e c u r v e s . i v ) P u m p s p e c i f i c a t i o n s f o r p r i m a r y c l a r i f i e r u n d e r f l o w a n d r e t u r n a c t i v a t e d s l u d g e p u m p s . - 44 -v ) R a w s e w a g e , p r i m a r y e f f l u e n t a n d f i n a l e f f l u e n t c h a r a c t e r i z a t i o n s . S p e c i f i c a l l y , a n a l y s e s o f B O D 5 / C O D , T S S , V S S , N H 3 , N 0 3 , T K N , T P , t e m p e r a t u r e a n d DO w e r e r e q u e s t e d . v i ) E f f l u e n t s t a n d a r d s . v i i ) D e s c r i p t i o n s o f s l u d g e h a n d l i n g a n d d i s p o s a l p r a c t i c e s a n d t h e i r a s s o c i a t e d c o s t s . y i i i ) C h e m i c a l t y p e a n d d o s a g e u s e d f o r p h o s p h o r u s r e m o v a l . -i x ) C u r r e n t c h e m i c a l c o s t s . x ) S l u d g e c h a r a c t e r i s t i c s . F o l l o w i n g t h e r e c e i p t o f d e s i g n a n d o p e r a t i n g d a t a , p r e l i m i n a r y r e t r o f i t d e s i g n s w e r e p r e p a r e d f o r e a c h p l a n t . D e s i g n s c o n s i s t e d o f m o d i f i e d p r o c e s s f l o w d i a g r a m s w h i c h i d e n t i f i e d c h a n g e s t o t h e e x i s t i n g p r o c e s s , a n d n e w e q u i p m e n t a n d p i p i n g r e q u i r e m e n t s . M e e t i n g s w e r e t h e n h e l d o n s i t e w i t h t h e p l a n t s t a f f t o r e v i e w t h e f e a s i b i l i t y a n d p r a c t i c a l i t y o f t h e r e t r o f i t d e s i g n s . I n s p e c t i o n s o f t h e p l a n t s w e r e c a r r i e d o u t t o f u r t h e r a s s i s t i n t h e r e f i n e m e n t o f t h e d e s i g n s . T h e r e t r o f i t d e s i g n s w e r e t h e n r e v i s e d a s r e q u i r e d , t o i n c l u d e i n p u t r e c e i v e d f r o m t h e r e v i e w m e e t i n g s a n d t h e p l a n t i n s p e c t i o n s . F i n a l i z e d r e t r o f i t p r o c e s s f l o w d i a g r a m s a n d l a y o u t d r a w i n g s w e r e t h e n d e v e l o p e d . A d e s c r i p t i o n o f t h e d e s i g n b a s i s u s e d i n p r e p a r i n g t h e r e t r o f i t d e s i g n s i s p r e s e n t e d i n S e c t i o n 3.3. - 4 5 -U p o n c o m p l e t i o n o f t h e r e v i s e d p r o c e s s f l o w d i a g r a m s a n d l a y o u t d r a w i n g s , i n c r e m e n t a l M T O ' s w e r e p r e p a r e d . T h i s i n v o l v e d d e t e r m i n i n g t h e q u a n t i t i e s o f m a t e r i a l s r e q u i r e d f o r t h e B i o - P r e t r o f i t o v e r a r i d a b o v e t h o s e r e q u i r e d f o r a n e q u i v a l e n t c h e m i c a l r e m o v a l p r o c e s s . D e s c r i p t i o n s o f t h e l e v e l o f d e t a i l i n c l u d e d i n t h e s e M T O ' s a r e p r e s e n t e d i n S e c t i o n 3 . 4 . A t t h i s t i m e , i n c r e m e n t a l o p e r a t i n g q u a n t i t i e s ( e . g . c h e m i c a l s , l a b o u r , p o w e r ) w e r e a l s o c a l c u l a t e d . A f t e r c o m p l e t i n g M T O ' s , c o s t e s t i m a t i n g w a s c a r r i e d o u t . T h e b a s i s f o r a l l e s t i m a t i n g ( b o t h c a p i t a l c o s t s a n d o p e r a t i n g c o s t s ) i s p r e s e n t e d i n S e c t i o n 3 . 4 . T h e e c o n o m i c a n a l y s i s f o r e a c h p l a n t w a s t h e n p e r f o r m e d . S e c t i o n 3 . 5 d e s c r i b e s t h e m e t h o d o f a n a l y s i s c h o s e n a n d t h e r a t i o n a l e b e h i n d i t s s e l e c t i o n . A n o v e r a l l a s s e s s m e n t o f t h e p o t e n t i a l f o r B i o - P r e m o v a l i n C a n a d a w a s t h e n m a d e a n d c o n c l u s i o n s a n d r e c o m m e n d a t i o n s w e r e d e v e l o p e d . 3 . 2 P l a n t S e l e c t i o n B a s i s I n o r d e r t o o b t a i n a r e p r e s e n t a t i v e c r o s s - s e c t i o n o f t r e a t m e n t p l a n t s , t h e f o l l o w i n g c r i t e r i a w e r e u s e d t o s e l e c t p l a n t s f o r s t u d y : - 4 6 -i ) P l a n t s s h o u l d b e s e l e c t e d f r o m t h e d i f f e r e n t r e g i o n s o f t h e c o u n t r y c u r r e n t l y h a v i n g p h o s p h o r u s r e m o v a l s t a n d a r d s o r w h e r e f u t u r e p h o s p h o r u s r e m o v a l s t a n d a r d s a r e f o r e s e e a b l e . i i ) P l a n t s s h o u l d b e o f e i t h e r t h e a c t i v a t e d s l u d g e o r e x t e n d e d a e r a t i o n t y p e . I n t u i t i v e l y i t w a s f e l t t h a t r e t r o f i t t i n g p r i m a r y p l a n t s f o r B i o - P r e m o v a l w a s n o t e c o n o m i c . T h i s w a s c o n f i r m e d b y C a n v i r o e t a l . ( 1 9 8 6 ) . I t w a s a l s o f e l t t h a t B i o - P t e c h n o l o g y h a s n o t s u f f i c i e n t l y a d v a n c e d t o c o n s i d e r t h e r e t r o f i t o f o t h e r s e c o n d a r y t r e a t m e n t p r o c e s s e s ( e . g . R B C ' s , t r i c k l i n g f i l t e r s , S B R ' s , l a g o o n s ) . i i i ) N e w f a c i l i t i e s s h o u l d b e c o n s i d e r e d i n a d d i t i o n t o e x i s t i n g f a c i l i t i e s . i v ) A r a n g e o f p l a n t s i z e s s h o u l d b e c o n s i d e r e d . v ) A r a n g e o f n u t r i e n t r e m o v a l r e q u i r e m e n t s s h o u l d b e c o n s i d e r e d . v i ) A v a r i e t y o f s l u d g e p r o c e s s i n g t e c h n i q u e s s h o u l d b e c o n s i d e r e d . v i i ) A m a n a g e a b l e n u m b e r o f p l a n t s s h o u l d b e s e l e c t e d . - 4 7 -v i i i ) T h e p l a n t s t a f f m u s t b e w i l l i n g t o p a r t i c i p a t e i n t h e s t u d y . U s i n g t h e s e c r i t e r i a , n i n e p l a n t s w e r e s e l e c t e d f o r s t u d y . A l i s t i n g o f t h e s e , c o m p l e t e w i t h d e s c r i p t i o n s , i s p r e s e n t e d i n T a b l e 3 . 1 . A f e w c o m m e n t s o n t h e s e l e c t i o n o f t h e s e p l a n t s a r e w a r r a n t e d . A s s h o w n o n T a b l e 3 . 1 , o n l y p l a n t s f r o m A l b e r t a , S a s k a t c h e w a n a n d O n t a r i o w e r e c o n s i d e r e d e v e n t h o u g h p h o s p h o r u s r e m o v a l s t a n d a r d s a l s o e x i s t i n B r i t i s h C o l u m b i a , M a n i t o b a , Q u e b e c a n d N e w B r u n s w i c k . P l a n t s i n M a n i t o b a w e r e n o t c o n s i d e r e d a s t h e t w o p l a n t s i n t h i s p r o v i n c e c u r r e n t l y h a v i n g p h o s p h o r u s r e m o v a l s t a n d a r d s a r e b o t h s m a l l b a t c h l a g o o n o p e r a t i o n s a n d a r e t h e r e f o r e , n o t a p p l i c a b l e t o B i o - P r e m o v a l . A c c o r d i n g t o P e t e r s o n ( 1 9 8 7 ) t h e s e p l a n t s a r e i s o l a t e d c a s e s a n d f u t u r e p h o s p h o r u s r e m o v a l r e q u i r e m e n t s i n M a n i t o b a a r e n o t a n t i c i p a t e d . S i m i l a r l y , p l a n t s i n New B r u n s w i c k w e r e n o t c o n s i d e r e d s i n c e t h e o n l y p l a n t c u r r e n t l y h a v i n g p h o s p h o r u s r e m o v a l s t a n d a r d s i s a n o x i d a t i o n d i t c h f o r t h e t o w n o f M c A d a m ( p o p u l a t i o n 1 , 8 0 0 ) . T h i s a g a i n , i s c o n s i d e r e d t o b e a n i s o l a t e d c a s e . P L A N T E d m o n t o n G o l d B a r D E S I G N F L O W f m ^ / d i P R O C E S S D E S C R I P T I O N 3 4 0 0 0 0 C a l g a r y B o n n y b r o o k R e g i n a 4 5 0 0 0 0 9 0 9 1 9 S a s k a t o o n H . A . M c l v o r W e i r 9 0 9 1 9 W i n d s o r L i t t l e R i v e r i ) E x i s t i n g 3 6 2 8 1 P l a n t i i ) C u r r e n t 2 7 2 1 1 E x p a n s i o n P r i m a r y c l a r i f i e r s , t w o s t a g e a n a e r o b i c d i g e s t i o n s l u d g e l a g o o n s C o n v e n t i o n a l a c t i v a t e d s l u d g e , c e n t r i f u g e s , l a n d f i l l d i s p o s a l C o n v e n t i o n a l a c t i v a t e d s l u d g e , c e n t r i f u g e s , l a n d f i l l d i s p o s a l N U T R I E N T R E M O V A L R E Q U I R E M E N T S  P H O S P H O R U S N I T R O G E N ( m g / L - P ) ( m g / L - N ) C O M M E N T S C o n v e n t i o n a l a c t i v a t e d s l u d g e , s i n g l e s t a g e a n a e r o b i c d i g e s t i o n , s l u d g e l a g o o n s C o n v e n t i o n a l a c t i v a t e d s l u d g e , s i n g l e s t a g e a n a e r o b i c d i g e s t i o n , s l u d g e l a g o o n s A e r a t e d l a g o o n s , t w o s t a g e a n a e r o b i c d i g e s t i o n , b e l t f i l t e r p r e s s e s N o n e T P < 1 . 0 N o n e T P < 1 . 0 T P < 1 . 0 N o v - A p r T P < 0 . 3 M a y - O c t N o n e T P < 1 . 0 N o n e ( M a y - O c t ) T P < 1 . 2 5 ( N o v - A p r ) N o n e N o n e P o t e n t i a l P r e m o v a l r e q u i r e -m e n t R a n f u l l - s c a l e B i o - P t e s t i n 1 9 8 6 / 8 7 P o t e n t i a l e x p a n -s i o n t o a c t i v a t e d s l u d g e i n 1 9 9 0 P o t e n t i a l N H _ r e m o v a l r e q u i r e -m e n t P o t e n t i a l e x p a n s i o n t o s e c o n d a r y t r e a t -m e n t a n d P r e m o v a l i n n e x t 5 - 1 0 y e a r s N o n e N e w f a c i l i t y w i l l s h a r e g r i t r e m o v a l a n d N H _ < 4 s l u d g e p r o c e s s i n g N o v - A p r f a c i l i t i e s w i t h N H _ < 1 e x i s t i n g f a c i l i t y M a y - O c t R a n f u l l - s c a l e B i o - P t e s t i n 1 9 8 5 - 8 6 T A B L E 3 . 1 - W A S T E W A T E R T R E A T M E N T P L A N T S S T U D I E D PLANT 6 . G r i m s b y B a k e r R o a d O n t a r i o 7 . M i l t o n O n t a r i o 8 . E l m i r a O n t a r i o 9 . W e l l e s l e y O n t a r i o D E S I G N F L O W f r n ^ / d i 1 8 1 4 0 1 2 9 1 1 4 5 5 0 5 0 0 P R O C E S S D E S C R I P T I O N C o n v e n t i o n a l a c t i v a t e d s l u d g e ( c o m p l e t e l y m i x e d r e a c t o r s ) , t w o s t a g e a n a e r o b i c d i g e s t i o n , l a n d a p p l i c a t i o n o f s l u d g e C o n v e n t i o n a l a c t i v a t e d s l u d g e , t w o s t a g e a n a e r o b i c d i g e s t i o n , l a n d a p p l i c a t i o n o f s l u d g e C o n v e n t i o n a l a c t i v a t e d s l u d g e , c h e m i c a l c o n d i t i o n i n g o f s l u d g e , f i l t e r p r e s s , d i s p o s a l t o l a n d f i l l E x t e n d e d a e r a t i o n , l a n d a p p l i c a t i o n o f s l u d g e N U T R I E N T R E M O V A L R E Q U I R E M E N T S  P H O S P H O R U S N I T R O G E N ( m g / L - P ) ( m g / L - N ) T P < 1 . 0 N o n e S P < 0 . 4 3 T P < 1 . 0 T P < 1 . 0 90% N H -r e m o v a l T K N < 3 . 5 ( A p r - O c t ) N H - < 7 . 5 ( N O v - M a r ) N o n e C O M M E N T S T A B L E 3 . 1 - W A S T E W A T E R T R E A T M E N T P L A N T S S T U D I E D ( c o n t ' d ) - 5 0 -P l a n t s i n B r i t i s h C o l u m b i a w e r e n o t c o n s i d e r e d a s i t w a s f e l t t h a t t h e r e w a s l i t t l e p o t e n t i a l f o r B i o - P r e m o v a l o u t s i d e o f i t s p r e s e n t a p p l i c a t i o n i n t h e O k a n a g a n V a l l e y . T h e r e a r e o n l y t w o p l a n t s o u t s i d e o f t h e O k a n a g a n V a l l e y ( K a m l o o p s a n d W h i s t l e r ) w h i c h c u r r e n t l y h a v e p h o s p h o r u s r e m o v a l r e q u i r e m e n t s ( E n v i r o n m e n t C a n a d a , 1 9 8 6 ) . A d d i t i o n a l p h o s p h o r u s r e m o v a l r e q u i r e m e n t s i n t h e f o r e s e e a b l e f u t u r e a r e u n l i k e l y ( W e t t e r , 1 9 8 7 ) . I n a d d i t i o n , i t w a s f e l t t h a t t h e u s e o f B i o - P i n t h e O k a n a g a n V a l l e y r e f l e c t e d i n g e n e r a l o n t h e v i a b i l i t y o f t h e p r o c e s s i n t h e p r o v i n c e . O r i g i n a l l y i t w a s i n t e n d e d t o s t u d y o n e o r t w o p l a n t s i n Q u e b e c . C o n t a c t s a t t h e p r o v i n c i a l M i n i s t r y o f t h e E n v i r o n m e n t . 3 w e r e m a d e a n d d e s i g n a n d o p e r a t i n g d a t a f o r t h e 5 0 , 0 0 0 m / d a c t i v a t e d s l u d g e p l a n t i n t h e C i t y o f G r a n b y w a s o b t a i n e d . H o w e v e r , b e c a u s e o f s c h e d u l e c o n s t r a i n t s , a c o m p l e t e a n a l y s i s w a s n o t c a r r i e d o u t . T h e p o t e n t i a l f o r t h e u s e o f B i o - P r e m o v a l i n Q u e b e c i s d i s c u s s e d , h o w e v e r , i n g e n e r a l t e r m s i n S e c t i o n 5 . A r e v i e w o f t h e p l a n t s s e l e c t e d s h o w s t h a t a l l o f t h e l a r g e p l a n t s s t u d i e d w e r e l o c a t e d i n W e s t e r n C a n a d a . I d e a l l y , l a r g e p l a n t s i n O n t a r i o w o u l d a l s o h a v e b e e n s t u d i e d . H o w e v e r , C a l g a r y , E d m o n t o n a n d R e g i n a h a v e a l l p r e v i o u s l y c o n s i d e r e d B i o - P r e m o v a l f o r t h e i r o p e r a t i o n s , a n d h e n c e , w e r e i n t e r e s t e d - 5 1 -i n b e i n g i n v o l v e d i n t h e s t u d y . S a s k a t o o n w a s s e l e c t e d a s i t o f f e r e d t h e o p p o r t u n i t y t o e v a l u a t e t h e f e a s i b i l i t y o f a n e s s e n t i a l l y n e w i n s t a l l a t i o n . T h e r e f o r e , i n o r d e r t o e n s u r e b o t h a v a r i e t y o f p l a n t s i z e s a n d m a i n t a i n a m a n a g e a b l e s c o p e o f w o r k , n o l a r g e p l a n t s f r o m O n t a r i o w e r e c o n s i d e r e d . H o w e v e r , t h e a p p l i c a b i l i t y o f B i o - P r e m o v a l t o l a r g e O n t a r i o p l a n t s i s d i s c u s s e d i n S e c t i o n 5 . N i t r i f i c a t i o n / d e n i t r i f i c a t i o n p l a n t s w e r e a l s o n o t s e l e c t e d f o r d e t a i l e d s t u d y . H o w e v e r , t h e s e p l a n t s o f f e r p o t e n t i a l f o r B i o - P r e t r o f i t s a n d h e n c e , a r e t h e s u b j e c t o f d i s c u s s i o n i n S e c t i o n 5 . 3 . 3 P l a n t D e s i g n B a s i s T h e r e t r o f i t d e s i g n s p r e p a r e d f o r t h e n i n e p l a n t s w e r e b a s e d o n t h e b i o c h e m i c a l p r i n c i p l e s o f B i o - P r e m o v a l r a t h e r t h a n o n t h e v a r i o u s p a t e n t e d a n d p u b l i s h e d p r o c e s s e s a v a i l a b l e . I t w a s f e l t t h a t o n e o f t h e p r o b l e m s w i t h p a s t a s s e s s m e n t s o f B i o - P t e c h n o l o g y h a s b e e n t h e t e n d e n c y t o a t t e m p t t o r e t r o f i t p a t e n t e d B i o - P p r o c e s s e s i n t o a n e x i s t i n g p l a n t , r a t h e r t h a n l o o k i n g a t w a y s t o c r e a t e c o n d i t i o n s c o n d u c i v e t o B i o - P b a c t e r i a g r o w t h . T h e r e f o r e , t h e p l a n t d e s i g n s w e r e b a s e d o n t h e p r e s e n t u n d e r s t a n d i n g o f t h e B i o - P r e m o v a l m e c h a n i s m a s s u m m a r i z e d i n S e c t i o n 2 . 1 . B y t r a n s l a t i n g t h i s u n d e r s t a n d i n g i n t o p r a c t i c a l - 52 -t e r m s , i t w a s c o n c l u d e d t h a t t h e r e a r e f o u r r e q u i r e m e n t s f o r t h e s u c c e s s f u l d e s i g n a n d o p e r a t i o n o f a B i o - P p l a n t . T h e s e a r e a s f o l l o w s : i ) B i o l o g i c a l s o l i d s m u s t b e e x p o s e d t o a l t e r n a t i n g p e r i o d s o f a n a e r o b i c a n d a e r o b i c c o n d i t i o n s . i i ) A s u f f i c i e n t c o n c e n t r a t i o n o f V F A ' s ( a p p r o x i m a t e l y 1 5 m g / L a s H A c ) m u s t b e p r e s e n t d u r i n g t h e a n a e r o b i c c o n d i t i o n s t o r e m o v e u p t o 5 m g / L o f p h o s p h o r u s . i i i ) N i t r a t e s a n d d i s s o l v e d o x y g e n m u s t n o t c o m e i n t o c o n t a c t w i t h t h e b i o l o g i c a l s o l i d s d u r i n g t h e i r e x p o s u r e t o t h e V F A ' s ( i . e . d u r i n g t h e a n a e r o b i c c o n d i t i o n s ) . i v ) B e c a u s e B i o - P b a c t e r i a r e l e a s e t h e i r s t o r e d p h o s p h o r u s u n d e r b o t h a n a e r o b i c a n d l o n g - t e r m a e r o b i c c o n d i t i o n s , s l u d g e p r o c e s s i n g s y s t e m s m u s t e i t h e r p r e v e n t e x p o s u r e o f t h e B i o - P s l u d g e t o t h e s e c o n d i t i o n s o r p r o v i d e f o r t h e r e m o v a l o f r e l e a s e d p h o s p h o r u s f r o m r e c y c l e d s t r e a m s . T h e a p p l i c a t i o n o f t h e s e f o u r r e q u i r e m e n t s i m p a c t s o n t h e d e s i g n a n d o p e r a t i o n o f m a n y o f t h e u n i t o p e r a t i o n s i n a w a s t e w a t e r t r e a t m e n t p l a n t . T h e f o l l o w i n g s e c t i o n s o u t l i n e t h e i m p a c t s a n d d e s c r i b e h o w t h e d e s i g n s o f t h e s e o p e r a t i o n s w e r e m o d i f i e d f o r B i o - P r e m o v a l . I n s o d o i n g , t h e d e s i g n p r o c e d u r e e m p l o y e d f o r t h e r e t r o f i t d e s i g n s i s p r e s e n t e d . - 53 -3 . 3 . 1 G r i t R e m o v a l I n t h e d e s i g n o f a n e w B i o - P p l a n t , a e r a t e d g r i t r e m o v a l s h o u l d b e a v o i d e d a s i t r e s u l t s i n t h e o x i d a t i o n o f V F A ' s c o n t a i n e d i n t h e i n f l u e n t s e w a g e . A l l o f t h e p l a n t s c o n s i d e r e d i n t h i s s t u d y , w i t h t h e e x c e p t i o n o f t h e W e l l e s l e y e x t e n d e d a e r a t i o n p l a n t , u t i l i z e d a e r a t e d g r i t r e m o v a l . H o w e v e r , s i n c e p r i m a r y s l u d g e f e r m e n t a t i o n w a s p r o v i d e d i n a l l c a s e s , t h e r e m o v a l o f t h e a e r a t e d g r i t t a n k s f r o m s e r v i c e , w a s n o t d e e m e d n e c e s s a r y . O p e r a t i o n o f t h e g r i t r e m o v a l f a c i l i t i e s a r e n o t a f f e c t e d b y a n y o f t h e m o d i f i c a t i o n s r e q u i r e d f o r B i o - P r e m o v a l . T h e r e f o r e , i n p r e p a r i n g m a t e r i a l b a l a n c e s i t w a s a s s u m e d t h a t t h e c u r r e n t p e r f o r m a n c e o f t h e f a c i l i t i e s w a s m a i n t a i n e d . 3 . 3 . 2 P r i m a r y C l a r i f i e r s R e t r o f i t t i n g f o r B i o - P r e m o v a l h a s n o e f f e c t o n t h e p e r f o r m a n c e o f t h e p r i m a r y c l a r i f i e r s u n l e s s f e r m e n t e r s o l i d s a r e r e c y c l e d b a c k t o t h e c l a r i f i e r s . S i n c e t h i s w a s n o t p r o p o s e d f o r a n y o f t h e p l a n t s , i t w a s a s s u m e d t h a t c u r r e n t B O D , S S a n d p h o s p h o r u s r e m o v a l p e r c e n t a g e s w o u l d b e m a i n t a i n e d . - 54 -T h e o p e r a t i o n o f t h e p r i m a r y c l a r i f i e r s c h a n g e s i n c e t h e u n d e r f l o w s l u d g e p u m p i n g r a t e i s i n c r e a s e d t o m i n i m i z e f e r m e n t a t i o n i n t h e c l a r i f i e r a n d a s s i s t w i t h V F A e l u t r i a t i o n i n t h e f e r m e n t e r . U n d e r f l o w s l u d g e p u m p i n g r a t e s o f u p t o 5 p e r c e n t o f t h e p l a n t i n f l u e n t a t a v e r a g e f l o w c o n d i t i o n s m a y b e r e q u i r e d . U n d e r f l o w p u m p i n g r a t e s m a y a l s o v a r y b e t w e e n 1 a n d 5 p e r c e n t d e p e n d i n g u p o n t h e p e r f o r m a n c e o f t h e f e r m e n t e r . T h e r e f o r e , t h e e x i s t i n g u n d e r f l o w s l u d g e p u m p s i n e a c h p l a n t w e r e c h e c k e d t o e n s u r e t h a t t h e y c o u l d p r o v i d e t h e r e q u i r e d c a p a c i t y a n d t h e d e s i r e d r a n g e o f f l o w s . A 1 0 0 p e r c e n t s p a r e w a s a l s o d e e m e d n e c e s s a r y . P u m p d i s c h a r g e h e a d s w e r e a l s o c h e c k e d t o e n s u r e t h a t t h e s l u d g e c o u l d b e p u m p e d i n t o a f u l l f e r m e n t e r . 3 . 3 . 3 P r i m a r y S l u d g e F e r m e n t a t i o n A s p r e v i o u s l y m e n t i o n e d , t h e p r e s e n c e o f a p p r o x i m a t e l y 1 5 m g / L o f V F A ' s ( a s a c e t a t e ) i n t h e a n a e r o b i c z o n e o f a B i o - P b i o r e a c t o r i s e s s e n t i a l t o p r o m o t e t h e g r o w t h o f B i o - P b a c t e r i a . I t w a s a l s o n o t e d t h a t , i n t h e a b s e n c e o f a n e x t e r n a l V F A s u p p l y , t h e m a i n s t r e a m B i o - P p r o c e s s e s a r e s o l e l y d e p e n d e n t u p o n s u f f i c i e n t V F A ' s b e i n g p r e s e n t i n t h e i n f l u e n t t o t h e b i o r e a c t o r . I n m a n y i n s t a n c e s , s u f f i c i e n t q u a n t i t i e s a r e n o t p r e s e n t . N i c h o l l s e t a l . ( 1 9 8 6 ) r e p o r t i m p r o v e d p h o s p h o r u s - 5 5 -r e m o v a l a t t h e J o h a n n e s b u r g N o r t h e r n W o r k s w a s t e w a t e r t r e a t m e n t p l a n t t h r o u g h V F A a d d i t i o n t o t h e a n a e r o b i c z o n e o f t h e b i o r e a c t o r . O l d h a m ( 1 9 8 6 ) s u g g e s t e d t h a t t h e a b s e n c e o f V F A ' s i n t h e i n f l u e n t t o t h e W i n d s o r L i t t l e R i v e r w a s t e w a t e r t r e a t m e n t p l a n t w a s r e s p o n s i b l e f o r t h e p o o r p e r f o r m a n c e o f a f u l l - s c a l e B i o - P t e s t . O l d h a m ( 1 9 8 5 ) a l s o n o t e s t h e i m p r o v e d p e r f o r m a n c e o f t h e K e l o w n a w a s t e w a t e r t r e a t m e n t p l a n t t h r o u g h V F A a d d i t i o n t o t h e a n a e r o b i c z o n e o f t h e b i o r e a c t o r . B a r n a r d ( 1 9 8 4 ) n o t e s t h a t g o o d p h o s p h o r u s r e m o v a l w a s e x p e r i e n c e d i n S o u t h A f r i c a n B i o - P p l a n t s c o n n e c t e d t o l o n g , s e p t i c s e w e r s . H o w e v e r , p o o r r e m o v a l w a s e x p e r i e n c e d i n B i o - P p l a n t s w h e r e t h e s e w a g e a r r i v e d a t t h e p l a n t i n a f r e s h a n d h e n c e , V F A d e f i c i e n t , c o n d i t i o n . T h e r e f o r e , b o t h O l d h a m a n d B a r n a r d r e c o m m e n d t h e a d d i t i o n o f V F A ' s t o t h e a n a e r o b i c z o n e o f t h e b i o r e a c t o r . V F A a d d i t i o n t o t h e s t r i p p e r t a n k o f t h e P h o s t r i p p r o c e s s c o u l d a l s o b e b e n e f i c i a l . A s p r e v i o u s l y m e n t i o n e d , V F A ' s f o r t h e P h o s t r i p p r o c e s s a r e g e n e r a t e d t h r o u g h e n d o g e n o u s d e c a y f o l l o w e d b y f e r m e n t a t i o n . T h e a d d i t i o n o f a V F A - r i c h s t r e a m c o u l d r e d u c e t h e s i z e o f s t r i p p e r r e q u i r e d . T h i s h a s b e e n r e c o g n i z e d b y t h e d e v e l o p e r s o f t h e p r o c e s s a s e v i d e n c e d b y t h e e m e r g e n c e o f t h e P h o s t r i p I I p r o c e s s . P o s s i b l e m e t h o d s o f i n c r e a s i n g t h e V F A s u p p l y t o t h e a n a e r o b i c z o n e a r e a s f o l l o w s : - 5 6 -i ) B y - p a s s t h e p r i m a r y c l a r i f i e r s a n d d i v e r t t h e e n t i r e i n f l u e n t f l o w t o t h e b i o r e a c t o r . i i ) P u r c h a s e o f V F A - r i c h s o l u t i o n s ( e . g . a c e t i c a c i d ) . i i i ) P r o d u c e V F A ' s t h r o u g h p r i m a r y s l u d g e f e r m e n t a t i o n . B e c a u s e V F A ' s w e r e n o t m e a s u r e d i n t h e i n f l u e n t t o e i g h t o u t o f t h e n i n e p l a n t s s t u d i e d , i t w a s n o t p o s s i b l e t o a s c e r t a i n i f s u f f i c i e n t q u a n t i t i e s w e r e p r e s e n t t o p r o m o t e t h e g r o w t h o f B i o - P b a c t e r i a . H o w e v e r , i n C a n a d i a n p l a n t s w h e r e V F A ' s h a v e b e e n m e a s u r e d ( K e l o w n a - O l d h a m , 1 9 8 5 , W i n d s o r L i t t l e R i v e r - O l d h a m , 1 9 8 6 a n d P e n t i c t o n - T u r k , 1 9 8 8 ) i t w a s d e t e r m i n e d t h a t s u f f i c i e n t V F A ' s w e r e n o t a v a i l a b l e o n a r e g u l a r b a s i s t o s u p p o r t r e l i a b l e B i o - P r e m o v a l . T h e r e f o r e , f o r t h e p u r p o s e s o f t h i s s t u d y , i t w a s a s s u m e d t h a t V F A a d d i t i o n t o t h e a n a e r o b i c z o n e w o u l d b e r e q u i r e d f o r a l l p l a n t s . B y - p a s s i n g o f t h e p r i m a r y c l a r i f i e r w a s n o t d e e m e d a c c e p t a b l e f o r i n c r e a s i n g t h e V F A c o n c e n t r a t i o n s i n t h e a n a e r o b i c z o n e , a s i t w a s a s s u m e d t h a t t h e i n f l u e n t s e w a g e w a s n o t i n a s u f f i c i e n t l y s e p t i c c o n d i t i o n . T h e p u r c h a s e o f b u l k a c e t i c a c i d a s a V F A s o u r c e w a s c o n s i d e r e d b u t w a s d e t e r m i n e d n o t t o b e e c o n o m i c a l l y f e a s i b l e . A s s u m i n g a b u l k c o s t o f $ 1 . 1 3 / k g ( S p e t h , 1 9 8 8 ) a n d a d o s a g e o f 1 5 m g / L , t h e a n n u a l c o s t o f s u p p l y a l o n e w o u l d r a n g e f r o m a p p r o x i m a t e l y $ 3 , 1 0 0 f o r - 57 -W e l l e s l e y t o $2.8 m i l l i o n f o r Calgary. W e l l e s l e y and C a l g a r y c u r r e n t l y spend o n l y $2,700 and $1.3 m i l l i o n , r e s p e c t i v e l y on an annual b a s i s f o r phosphorus removal c h e m i c a l s . In a d d i t i o n , a c e t i c a c i d feed systems would have t o be i n s t a l l e d and i n c r e a s e d energy c o s t s a s s o c i a t e d w i t h the o x i d a t i o n o f a c e t i c a c i d would be r e a l i z e d . C l e a r l y t h i s i s not a f e a s i b l e o p t i o n . T h e r e f o r e , the use of primary sludge f e r m e n t a t i o n was chosen as the o n l y v i a b l e method of producing VFA'si f o r the study . -The use of primary sludge f e r m e n t a t i o n t o produce VFA's i n v o l v e s r o u t i n g the primary sludge t o an anaerobic tank. The SRT of the tank i s maintained s u f f i c i e n t l y long t o promote the growth o f a c i d - f o r m i n g h e t e r o t r o p h i c b a c t e r i a , and s u f f i c i e n t l y s h o r t t o i n h i b i t the growth o f methane-forming b a c t e r i a . S i m i l a r l y , the HRT of the tank i s maintained s u f f i c i e n t l y l o n g t o permit the breakdown of carbon compounds, contained w i t h i n the primary sludge, i n t o o r g a n i c a c i d s ( i n c l u d i n g VFA's). B a s i c a l l y , the fermenter operates l i k e an anaerobic d i g e s t o r i n which methane formation has been suppressed. Four d i f f e r e n t process schemes f o r the o p e r a t i o n of a primary sludge fermenter have been proposed. These are i l l u s t r a t e d i n F i g u r e 3.1. Option 1 ( G r a v i t y Thickening) i s c u r r e n t l y used a t the Kelowna P l a n t (Oldham, 1985). At Kelowna, - 58 -p r i m a r y s l u d g e i s r o u t e d t o a g r a v i t y t h i c k e n e r h a v i n g a n H R T o f a p p r o x i m a t e l y 14 h o u r s . S u p e r n a t a n t f r o m t h e t h i c k e n e r i s r o u t e d d i r e c t l y t o t h e a n a e r o b i c z o n e o f t h e b i o r e a c t o r . T h e o p e r a t i o n o f t h i s p r o c e s s a p p e a r s t o b e t e m p e r a t u r e d e p e n d e n t a s V F A p r o d u c t i o n d r o p s f r o m a p p r o x i m a t e l y 1 6 mg H A c / L o f i n f l u e n t f l o w a t a s l u d g e t e m p e r a t u r e o f 22 ° C t o a p p r o x i m a t e l y 7 . 5 mg H A c / L o f i n f l u e n t f l o w a t a s l u d g e t e m p e r a t u r e o f 1 0 ° C ( S t e v e n s , 1 9 8 8 ) . O p t i o n 2 ( A c t i v a t e d P r i m a r y T a n k ) w a s p r o p o s e d b y B a r n a r d ( 1 9 8 4 ) . I t i n v o l v e s d i s c h a r g i n g p r i m a r y s l u d g e t o a g r a v i t y t h i c k e n e r a n d r e c y c l i n g s o m e o f t h e t h i c k e n e r u n d e r f l o w ( a s w e l l a s t h e s u p e r n a t a n t ) b a c k t o t h e p r i m a r y c l a r i f i e r s u c h t h a t a s l u d g e b l a n k e t i n t h e p r i m a r y c l a r i f i e r i s m a i n t a i n e d . A s a r e s u l t , f e r m e n t a t i o n s h o u l d t a k e p l a c e i n b o t h t h e c l a r i f i e r a n d t h e t h i c k e n e r . T h e r e c y c l i n g o f u n d e r f l o w a n d s u p e r n a t a n t w i l l a l s o a s s i s t i n e l u t r i a t i n g V F A ' s f r o m t h e s l u d g e . S R T i s c o n t r o l l e d b y t h e s o l i d s e s c a p i n g o v e r t h e c l a r i f i e r w e i r , a n d w a s t i n g f r o m t h e t h i c k e n e r t o t h e s l u d g e h a n d l i n g f a c i l i t i e s . W h i l e p r o v i d i n g g o o d c o n t r o l o v e r t h e f e r m e n t a t i o n p r o c e s s t h i s s y s t e m h o w e v e r , d o e s n o t p r o v i d e t h e f l e x i b i l i t y t o r o u t e a V F A - r i c h s i d e s t r e a m t o v a r i o u s l o c a t i o n s . T h e r e f o r e , i t w o u l d n o t b e f e a s i b l e t o i n c o r p o r a t e t h i s o p t i o n i n t o t h e P h o s t r i p p r o c e s s . I n a d d i t i o n , t h i s o p t i o n o f f e r s t h e p o t e n t i a l f o r V F A o x i d a t i o n b y h e t e r o t r o p h i c b a c t e r i a d u r i n g t r a n s p o r t a t i o n b e t w e e n t h e c l a r i f i e r a n d t h e b i o r e a c t o r . PRIMARY CLARIFIER THICKENER TO ANAEROBIC ZONE TO SLUDGE HANDLING OPTION 1 - GRAVITY THICKENING PRIMARY CLARIFIER FERMENTER Cte TO SLUDGE HANDLING OPTION 3 - COMPLETELY MIXED FERMENTER PRIMARY CLARIFIER TV" THICKENER TO SLUDGE HANDLING OPTION 2 - ACTIVATED PRIMARY TANK PRIMARY CLARIFIER TO ANAEROBIC ZONE OPTION U - GRAVITY THICKENER WITH RECYCLE F I G U R E 3 . 1 - P R I M A R Y S L U D G E F E R M E N T A T I O N P R O C E S S O P T I O N S - 6 0 -O p t i o n 3 ( C o m p l e t e l y M i x e d F e r m e n t e r ) w a s p r o p o s e d b y R a b i n o w i t z e t a l . ( 1 9 8 7 ) . B a s i c a l l y , i t i n v o l v e s t h e s a m e o p e r a t i o n a s t h e A c t i v a t e d P r i m a r y T a n k w i t h t h e e x c e p t i o n t h a t t h e f e r m e n t a t i o n t a n k i s c o m p l e t e l y m i x e d . T h i s p r o v i d e s f o r b e t t e r c o n t a c t b e t w e e n t h e o r g a n i c m o l e c u l e s a n d t h e b a c t e r i a a n d h e n c e , s h o u l d r e s u l t i n m o r e e f f i c i e n t f e r m e n t a t i o n . H o w e v e r , a s i n O p t i o n 2 , t h e p r o c e s s d o e s n o t p r o v i d e f l e x i b i l i t y w i t h r e s p e c t t o t h e d i s p o s i t i o n o f t h e V F A - r i c h s t r e a m , a n d t h e r e f o r e , t h e p o t e n t i a l f o r p r e m a t u r e V F A o x i d a t i o n s t i l l e x i s t s . I n a d d i t i o n , s l u d g e w a s t e d f r o m a c o m p l e t e l y m i x e d f e r m e n t e r w i l l h a v e a h i g h e r w a t e r c o n t e n t t h a n t h a t f r o m a t h i c k e n e r . T h e r e f o r e v o l u m e t r i c l o a d i n g s o n d o w n s t r e a m s l u d g e h a n d l i n g o p e r a t i o n s w i l l b e i n c r e a s e d . T h i s p r o c e s s h a s b e e n p r o p o s e d f o r t h e n e w P e n t i c t o n B i o - P p l a n t ( O l d h a m , 1 9 8 8 ) a n d i s c u r r e n t l y b e i n g u s e d a t t h e U B C p i l o t p l a n t . P i l o t p l a n t r e s u l t s s h o w t h a t t h e f e r m e n t e r g e n e r a l l y p r o d u c e s 1 0 - 2 0 mg H A c / L o f i n f l u e n t f l o w w h i l e o p e r a t i n g a t a n H R T o f 9 h o u r s a n d a n S R T o f 4 . 5 d a y s ( K o c h , 1 9 8 8 ) . O p t i o n 4 ( G r a v i t y T h i c k e n e r w i t h R e c y l e ) i s e s s e n t i a l l y a c o m b i n a t i o n o f O p t i o n s 1 , 2 a n d 3 . P r i m a r y s l u d g e i s r o u t e d t o a g r a v i t y t h i c k e n e r w h e r e f e r m e n t a t i o n t a k e s p l a c e a n d V F A - r i c h s u p e r n a t a n t i s d i r e c t e d t o t h e b i o r e a c t o r i n a m a i n s t r e a m p r o c e s s , o r t h e s t r i p p e r t a n k i n a s i d e s t r e a m p r o c e s s . T h i c k e n e r u n d e r f l o w i s r e c y c l e d b a c k t o t h e t h i c k e n e r t o e l u t r i a t e V F A ' s a n d t o p r o v i d e i n d e p e n d e n t S R T c o n t r o l . T h i s - 6 1 -p r o c e s s p r o v i d e s f l e x i b i l i t y w i t h r e s p e c t t o S R T c o n t r o l a n d V F A d i s t r i b u t i o n , a n d y e t m i n i m i z e s v o l u m e t r i c l o a d i n g s o n d o w n s t r e a m s l u d g e h a n d l i n g o p e r a t i o n s . S t e v e n s ( 1 9 8 8 ) i n d i c a t e s t h a t t h e e x i s t i n g p r i m a r y s l u d g e t h i c k e n i n g o p e r a t i o n a t t h e K e l o w n a p l a n t m a y b e u p g r a d e d s i m i l a r t o t h i s o p t i o n . L e s l i e ( 1 9 8 8 ) r e p o r t s t h a t t h i s m e t h o d w i l l b e u s e d t o g e n e r a t e V F A ' s f o r t h e n e w W e s t b a n k , B . C . B i o - P p l a n t . O f t h e f o u r o p t i o n s d i s c u s s e d i n S e c t i o n 2 . 2 . 6 a n d i l l u s t r a t e d i n F i g u r e 3 . 1 , o n l y t h e g r a v i t y t h i c k e n e r w i t h r e c y c l e ( O p t i o n 4 ) w a s u s e d i n t h e r e t r o f i t d e s i g n s . R e a s o n s f o r t h i s w e r e t h a t t h i s o p t i o n m i n i m i z e s s l u d g e v o l u m e s p r o v i d e s a n a d e q u a t e e n v i r o n m e n t f o r V F A p r o d u c t i o n , p r o v i d e s a d e q u a t e S R T c o n t o l , m a x i m i z e s o p e r a t i o n a l f l e x i b i l i t y w i t h r e s p e c t t o V F A d i s t r i b u t i o n , h a s b e e n s u c c e s s f u l l y o p e r a t e d a t K e l o w n a , h a s b e e n p r o p o s e d f o r t h e W e s t b a n k p l a n t , a n d m i n i m i z e s t o t a l c o s t s . T h e c o s t a s p e c t w i l l b e a d d r e s s e d f u r t h e r i n S e c t i o n 4 . 0 . A s i m p l i f i e d p r o c e s s f l o w d i a g r a m f o r a t y p i c a l p r i m a r y s l u d g e f e r m e n t e r s h o w i n g m e c h a n i c a l e q u i p m e n t , p i p i n g a n d m a j o r i n s t r u m e n t a t i o n r e q u i r e m e n t s i s i l l u s t r a t e d i n F i g u r e 3 . 2 . D e s i g n c r i t e r i a u s e d f o r t h e s e l e c t i o n a n d s i z i n g o f m e c h a n i c a l e q u i p m e n t a r e a s f o l l o w s : - 62 -i ) F e r m e n t e r T a n k H R T ( N o m i n a l ) = 8 h o u r s a t a p r i m a r y s l u d g e f l o w o f 5% o f t h e a v e r a g e p l a n t i n f l u e n t f l o w . SWD = 3 . 5 m ( m i n i m u m ) . T a n k t o b e i n s u l a t e d i f a b o v e g r o u n d . - S c r a p e r m e c h a n i s m r e q u i r e d . i i ) S u p e r n a t a n t P u m p s P r o v i d e 2 x 1 0 0 % h o r i z o n t a l , c e n t r i f u g a l , o p e n i m p e l l o r e n d s u c t i o n p u m p s . D e s i g n F l o w = 2 . 5 % o f t h e a v e r a g e p l a n t i n f l u e n t f l o w . F l o w c o n t r o l v i a t h r o t t l i n g o f e l e c t r o n i c a l l y a c t u a t e d b u t t e r f l y v a l v e . F l o w m e a s u r e m e n t v i a o r i f i c e m e t e r . L o c a l o r r e m o t e f l o w r e c o r d i n g ( s i t e s p e c i f i c ) . i i i ) W a s t e P u m p s P r o v i d e 2 x 1 0 0 % h o r i z o n t a l , c e n t r i f u g a l , o p e n i m p e l l o r , e n d s u c t i o n p u m p s . - D e s i g n F l o w = 2 . 5 % o f t h e a v e r a g e p l a n t i n f l u e n t f l o w . F l o w c o n t r o l v i a t h r o t t l i n g o f e l e c t r o n i c a l l y a c t u a t e d b u t t e r f l y v a l v e . F l o w m e a s u r e m e n t v i a o r i f i c e m e t e r . - 63 -SLUDGE FROM PRIMARY CLARIFIER • (FT) [FE THICKENER FERMENTER SUPERNATANT PUMPS FERMENTER RECYCLE PUMPS FERMENTER WASTE PUMPS FEJ TO BIOREACTOR I FE) FC FE FR FT TO SLUDGE HANDLING - Flow C o n t r o l l e r - Flow Measurement Element - Flow Recorder - Flow T r a n s m i t t e r FIGURE 3.2 - PRIMARY SLUDGE FERMENTER PROCESS FLOW DIAGRAM - 64 -L o c a l o r r e m o t e f l o w r e c o r d i n g ( s i t e s p e c i f i c ) . - T D H b a s e d o n p u m p i n g a n e a r e m p t y f e r m e n t e r i n t o a f u l l d i g e s t o r ( w h e r e a p p l i c a b l e ) , i v ) R e c y c l e P u m p s P r o v i d e 2 x 1 0 0 % h o r i z o n t a l , c e n t r i f u g a l , o p e n i m p e l l o r , e n d s u c t i o n p u m p s . D e s i g n F l o w = 2 . 5 % o f p l a n t i n f l u e n t a t a v e r a g e f l o w c o n d i t i o n s . F l o w c o n t r o l v i a t h r o t t l i n g o f e l e c t r o n i c a l l y a c t u a t e d b u t t e r f l y v a l v e . - F l o w m e a s u r e m e n t v i a o r i f i c e m e t e r . L o c a l o r r e m o t e f l o w r e c o r d i n g ( s i t e s p e c i f i c ) . F l o w s f o r c a l c u l a t i n g B O D a n d s o l i d s l o a d i n g s o n o t h e r u n i t o p e r a t i o n s w e r e c a l c u l a t e d b y p r e p a r i n g a s o l i d s b a l a n c e f o r t h e f e r m e n t e r . T h e f o l l o w i n g a s s u m p t i o n s w e r e u s e d i n p r e p a r i n g t h i s b a l a n c e : i ) U n d e r f l o w T S S = 4 % - 65 -N o t e : I n a c o n v e n t i o n a l p l a n t , t h i c k e n e d p r i m a r y s l u d g e i s g e n e r a l l y 6-12% s o l i d s ( M e t c a l f a n d E d d y , 1 9 7 9 ) . H o w e v e r , s i n c e t h e p r i m a r y c l a r i f i e r u n d e r f l o w r a t e i s i n c r e a s e d f o r t h e f e r m e n t e r o p e r a t i o n , i t w a s f e l t t h a t t h e t h i c k e n e r ' u n d e r f l o w , ; : c o n c e n t r a t i o n i w o u l d s u b s e q u e n t l y b e r e d u c e d . I i . . . i i ) S u p e r n a t a n t T S S = 2 5 0 m g / L ( M e t c a l f a n d E d d y , 1 9 7 9 ) i i i ) M a s s o f V S S s o l u b i l i z e d t o V F A ' s = 25% o f t h e V S S r e m o v e d b y t h e p r i m a r y c l a r i f i e r . N o t e : T h i s a s s u m p t i o n i s m a d e s u c h t h a t b o t h t h e B O D l o a d i n g o n t h e b i o r e a c t o r , a n d t h e w a s t e s l u d g e v o l u m e s c a n b e c a l c u l a t e d . I n a d d i t i o n , i t i s u s e d a s a c h e c k t o e n s u r e t h a t s u f f i c i e n t V F A ' s w e r e i n t r o d u c e d t o t h e b i o r e a c t o r . T h e a s s u m p t i o n i s d e r i v e d f r o m t h e w o r k c a r r i e d o u t • b y E a s t m a n a n d F e r g u s o n ( 1 9 8 1 ) w h o c o n c l u d e d t h a t t h e m a x i m u m p r o d u c t i o n o f s o l u b l e o r g a n i c c a r b o n d u r i n g t h e a c i d p h a s e o f a n a e r o b i c d i g e s t i o n , i s a p p r o x i m a t e l y 30% o f t h e i n f l u e n t C O D . i v ) G r o w t h o f f e r m e n t i n g b a c t e r i a i s n e g l i g i b l e c o m p a r e d t o t h e m a s s o f s o l i d s s e t t l e d f r o m t h e p l a n t i n f l u e n t . N o t e : T h e i m p a c t o f t h i s a s s u m p t i o n i s t h a t b i o m a s s c e l l p r o d u c t i o n i s i g n o r e d i n t h e o v e r a l l s o l i d s b a l a n c e . - 66 -3 . 3 . 4 B i o r e a c t o r D e s i g n o f t h e b i o r e a c t o r b a s i c a l l y i n v o l v e s c r e a t i n g a n a n a e r o b i c / a e r o b i c s e q u e n c e i n t h e r e a c t o r , a n d s t r a t e g i c a l l y p l a c i n g a n o x i c z o n e s t o p r e v e n t n i t r a t e s f r o m e n t e r i n g t h e a n a e r o b i c z o n e . P l u g f l o w r e a c t o r s o r c o m p l e t e l y m i x e d r e a c t o r s i n s e r i e s a r e r e q u i r e d t o c r e a t e t h e s e d i f f e r e n t e n v i r o n m e n t s w i t h i n t h e r e a c t o r . I n p l a n t s c u r r e n t l y h a v i n g p l u g f l o w r e a c t o r s , p a r t i t i o n s m u s t b e p l a c e d b e t w e e n t h e v a r i o u s z o n e s t o p r e v e n t b a c k m i x i n g . T y p i c a l l y , p a r t i t i o n s w e r e p r e s u m e d n e c e s s a r y t o c r e a t e c e l l s h a v i n g n o m i n a l r e t e n t i o n t i m e s o f 0 . 5 h o u r s . O p e n i n g s i n t h e p a r t i t i o n s w e r e s i z e d t o c r e a t e f l o w t h r o u g h v e l o c i t i e s o f 0 . 1 0 m / s . C o n c r e t e w a l l s h a v i n g t h i c k n e s s e s o f 250mm w e r e u s e d f o r p a r t i t i o n s i n a l l c a s e s . I n p l a n t s w h e r e l a r g e , c o m p l e t e l y m i x e d r e a c t o r s w e r e u s e d , p l u g f l o w c o n d i t i o n s w e r e c r e a t e d b y c o n s t r u c t i n g c o n c r e t e d i v i d i n g w a l l s w i t h i n t h e r e a c t o r . C o n s i d e r a t i o n w a s g i v e n t o t h e u s e o f o u t - o f - s e r v i c e t a n k s a n d d i s t r i b u t i o n c h a m b e r s f o r a n a e r o b i c a n d a n o x i c z o n e s . A s s h o w n i n S e c t i o n 2 . 0 , t h e r e a r e m a n y o p t i o n s f o r t h e s e q u e n c i n g o f a n a e r o b i c , a n o x i c a n d a e r o b i c z o n e s w i t h i n t h e r e a c t o r . A s a r e s u l t , t h e l a y o u t o f t h e b i o r e a c t o r s , w i t h r e s p e c t t o t h e l o c a t i o n a n d s i z i n g o f t h e d i f f e r e n t z o n e s , w e r e - 67 -o p t i m i z e d o n a n i n d i v i d u a l p l a n t b a s i s . F a c t o r s a f f e c t i n g t h e s e q u e n c i n g o f t h e a n a e r o b i c , a n o x i c a n d a e r o b i c z o n e s w e r e s e w a g e c h a r a c t e r i s t i c s ; n u t r i e n t r e m o v a l r e q u i r e m e n t s ; c o s t ; a n d o p e r a t i o n a l f l e x i b i l i t y . A n a e r o b i c a n d a n o x i c c o n d i t i o n s w e r e c r e a t e d b y s h u t t i n g o f f t h e a i r s u p p l y t o t h e d e s i g n a t e d c e l l s . M i x e r s , s i z e d f o r 4 W / M , w e r e i n s t a l l e d t o k e e p t h e b i o l o g i c a l s o l i d s i n s u s p e n s i o n a n d t o p r e v e n t o x y g e n t r a n s f e r t h r o u g h s u r f a c e r e n e w a l . A m i n i m u m o f t w o m i x e r s p e r c e l l w e r e p r o v i d e d . F l e x i b i l i t y o f o p e r a t i o n w a s e n s u r e d b y p r o v i d i n g a i r s u p p l y w i t h s h u t - o f f v a l v e s t o t h e m a j o r i t y o f t h e c e l l s . T h e r e f o r e , c e l l s c o u l d b e s h i f t e d b e t w e e n a e r a t e d a n d n o n - a e r a t e d c o n d i t i o n s . A u t o m a t i c DO c o n t r o l w a s p r o v i d e d i n a l l p l a n t s n o t p r e s e n t l y e m p l o y i n g t h i s t e c h n o l o g y . T h e o b j e c t i v e o f t h i s w a s t o e n s u r e t h a t DO c o n c e n t r a t i o n s i n t h e R A S w e r e n o t t o o h i g h t o a f f e c t a n a e r o b i c c o n d i t i o n s a t t h e f r o n t o f t h e b i o r e a c t o r . T h e i m p o r t a n c e o f t h i s h a s b e e n p r e v i o u s l y s t a t e d b y B a r n a r d ( 1 9 8 3 ) a n d K e a y ( 1 9 8 4 ) . DO c o n t r o l w a s p r o v i d e d w i t h a f e e d b a c k c o n t r o l l o o p . T w o DO p r o b e s w e r e p r o v i d e d i n t h e a e r o b i c z o n e o f e a c h r e a c t o r . - 68 -A p r o c e s s c o n t r o l l e r averages the DO measurements and sends an output s i g n a l to the a i r supply equipment key (e.g. to a c o n t r o l v a l v e on the i n l e t o f a c e n t r i f u g a l b l o w e r ) . A schematic of t h i s system i s p r e s e n t e d i n F i g u r e 3.3. Through t h i s system, i t was intended to m a i n t a i n the a e r o b i c zone DO between 1.5 and 2.0 mg/L. O x i d a t i o n r e d u c t i o n p o t e n t i a l (ORP) m o n i t o r i n g was p r o v i d e d i n the anaerobic and anoxic zones of a l l p l a n t s . Koch and Oldham (1985) r e p o r t on the u s e f u l n e s s of ORP t o d e t e c t the t r a n s i t i o n between anoxic and anaerobic c o n d i t i o n s d u r i n g l a b o r a t o r y s c a l e b a t c h t e s t s and p i l o t s c a l e flow through experiments. T h e r e f o r e , the m o n i t o r i n g of ORP w i l l p r o v i d e o n - l i n e measurement of t h e e f f e c t i v e n e s s of the anoxic zones i n p r o t e c t i n g the anaerobic zone from n i t r a t e i n t r u s i o n . Hardware r e q u i r e d f o r ORP m o n i t o r i n g i n c l u d e s two ORP probes per r e a c t o r (one i n the anaerobic zone and one i n the anoxic) and some form of o n - l i n e i n d i c a t o r and r e c o r d e r compatible w i t h the p l a n t ' s i n s t r u m e n t a t i o n and c o n t r o l system. A schematic drawing of the ORP m o n i t o r i n g system f o r a UCT p r o c e s s i s p r e s e n t e d i n F i g u r e 3.4. Process d e s i g n of the b i o r e a c t o r s i n v o l v e d c a l c u l a t i n g r e a c t o r volumes, sludge p r o d u c t i o n , oxygen requirements and e f f l u e n t c h a r a c t e r i s t i c s . In p l a n t s c u r r e n t l y h a v i n g a c t i v a t e d sludge or extended a e r a t i o n o p e r a t i o n s , i t was i n i t i a l l y assumed > AE - Process A n a l y z e r AIC - Process A n a l y s i s I n d i c a t o r / C o n t r o l l e r AT - Process A n a l y s i s T r a n s m i t t e r CENTRIFUGAL BLOWERS DUMMY LOAD F I G U R E 3.3 - A U T O M A T I C DO C O N T R O L S C H E M A T I C I (ATI AE - Process A n a l y z e r AIR - Process A n a l y s i s I n d i c a t o r / R e c o r d e r AT - Process A n a l y s i s T r a n s m i t t e r o 1 1 1 1 1 1 r 1 j ORP ANAEROBIC ORP . e ANOXIC AEROBIC F I G U R E 3 . 4 - O R P M O N I T O R I N G S C H E M A T I C F O R U C T P R O C E S S - 7 1 -t h a t t h e e x i s t i n g r e a c t o r v o l u m e w a s s u f f i c i e n t f o r B i o - P r e m o v a l . I n p l a n t s n o t p r e s e n t l y h a v i n g a c t i v a t e d s l u d g e o r e x t e n d e d a e r a t i o n , i t w a s i n i t i a l l y a s s u m e d t h a t t h e r e w a s n o d i f f e r e n c e b e t w e e n t h e r e a c t o r v o l u m e s r e q u i r e d f o r B i o - P a n d c h e m i c a l p h o s p h o r u s r e m o v a l , a n d t h a t t h i s v o l u m e w a s e q u i v a l e n t t o t h e n o m i n a l H R T f o r a c o n v e n t i o n a l a c t i v a t e d s l u d g e p l a n t . T h i s w a s a s s u m e d t o b e 6 t o 7 h o u r s ( O n t a r i o M i n i s t r y o f t h e E n v i r o n m e n t , 1 9 8 4 ) . T h e v a l i d i t y o f t h e s e a s s u m p t i o n s w a s c h e c k e d b y e n s u r i n g t h a t t h e r e q u i r e d b i o r e a c t o r M L S S d i d n o t c r e a t e a s o l i d s l o a d i n g p r o b l e m o n t h e s e c o n d a r y c l a r i f i e r . A n o t h e r s i g n i f i c a n t i n i t i a l a s s u m p t i o n w a s w i t h r e s p e c t t o p h o s p h o r u s r e m o v a l c a p a c i t y o f t h e B i o - P r e m o v a l m e c h a n i s m . A s m e n t i o n e d i n S e c t i o n 2 . 0 , t h e u s e o f e x i s t i n g k i n e t i c m o d e l s r e q u i r e s c o n s i d e r a b l e a m o u n t s o f d a t a n o t r e a d i l y a v a i l a b l e . I n s o m e c a s e s t h e m o d e l s w e r e n o t a p p l i c a b l e t o t h e s h o r t S R T p l a n t s c o m m o n t o C a n a d a . T h e r e f o r e , t h e s e m o d e l s w e r e n o t u s e d . I n s t e a d , a m e t h o d w a s d e v e l o p e d t o d e t e r m i n e w h e t h e r o r n o t i t w a s r e a s o n a b l e t o e x p e c t a B i o - P p r o c e s s t o r e m o v e p h o s p h o r u s t o a s p e c i f i e d s o l u b l e p h o s p h o r u s ( S P ) c o n c e n t r a t i o n . T h i s m e t h o d i s b a s e d o n t h e c o n c e p t t h a t t h e r e i s a n u p p e r l i m i t o n t h e p e r c e n t a g e o f p h o s p h o r u s c o n t a i n e d i n a B i o - P s l u d g e . A s s u m i n g t h a t t h e r e a r e s u f f i c i e n t V F A ' s p r e s e n t i n t h e a n a e r o b i c z o n e , t h i s w o u l d a p p e a r t o b e r e a s o n a b l e s i n c e t h e B O D _ : P r a t i o w i l l t h e n g o v e r n t h e a m o u n t o f p h o s p h o r u s w h i c h c a n - 72 -b e r e m o v e d f r o m t h e w a s t e w a t e r . S u p p o r t f o r t h i s c o m e s f r o m O l d h a m a n d S t e v e n s ( 1 9 8 4 ) w h o r e p o r t e d t h a t t h e p e r c e n t p h o s p h o r u s b y w e i g h t ( T S S b a s i s ) p e a k e d a t 6 . 2 5 % i n t h e K e l o w n a p l a n t . S t e p s i n v o l v e d i n a s s e s s i n g t h e p h o s p h o r u s r e m o v a l c a p a c i t y o f t h e p r o c e s s a r e a s f o l l o w s : i ) A s s u m e a n a c h i e v a b l e e f f l u e n t S P c o n c e n t r a t i o n . i i ) C a l c u l a t e t h e a m o u n t o f p h o s p h o r u s w h i c h w o u l d h a v e t o b e r e m o v e d b i o l o g i c a l l y t o a c h i e v e t h e e f f l u e n t s o l u b l e p h o s p h o r u s c o n c e n t r a t i o n a s s u m e d i n i ) . i i i ) C a l c u l a t e t h e WAS p r o d u c t i o n . i v ) C a l c u l a t e t h e r e q u i r e d p e r c e n t a g e p h o s p h o r u s i n t h e WAS t o a c h i e v e t h e e f f l u e n t s o l u b l e p h o s p h o r u s c o n c e n t r a t i o n a s s u m e d i n i ) . v ) I f t h e p e r c e n t a g e c a l c u l a t e d i n i v ) i s r e a s o n a b l e c o m p a r e d t o p u b l i s h e d f i g u r e s , c o n c l u d e t h a t t h e a s s u m p t i o n m a d e i n i ) i s r e a s o n a b l e . I f t h e p e r c e n t a g e c a l c u l a t e d i n i v ) i s s i g n i f i c a n t l y h i g h e r t h a n p u b l i s h e d f i g u r e s , c o n c l u d e t h a t t h e c o n c e n t r a t i o n i n i ) c a n n o t b e a c h i e v e d a n d s t a r t a g a i n . - 7 3 -I n m o s t c a s e s a n a c h i e v a b l e e f f l u e n t S P c o n c e n t r a t i o n o f 0 . 5 m g / L w a s a s s u m e d i n i t i a l l y f o r s t e p i ) . T h i s w a s b a s e d o n t h e g e n e r a l o p e r a t i n g e x p e r i e n c e o f t h e K e l o w n a p l a n t a n d t h e U B C p i l o t p l a n t . I t w a s t h e n a s s u m e d t h a t t h e m a x i m u m p e r c e n t a g e o f p h o s p h o r u s c o n t a i n e d i n t h e V S S w a s a p p r o x i m a t e l y 8 . 5 % o n a w e i g h t b a s i s . T h i s w a s b a s e d o n t h e r e p o r t s o f D a i g g e r e t a l . ( 1 9 8 7 ) w h o s u g g e s t e d t h a t p h o s p h o r u s c o n t e n t s o f 2 . . . A / 0 a n d A / 0 s l u d g e s a p p e a r t o r e a c h l i m i t i n g v a l u e s o f 8 t o 9 p e r c e n t o n a V S S b a s i s , a n d o f t h e p r e v i o u s l y m e n t i o n e d r e p o r t b y O l d h a m a n d S t e v e n s ( 1 9 8 4 ) f o r t h e K e l o w n a p l a n t . W h i l e i t m u s t b e r e c o g n i z e d t h a t t h i s m e t h o d i s s o m e w h a t c r u d e , i t d o e s p r o v i d e a n i n d i c a t i o n o f t h e a b i l i t y o f a p r o c e s s t o r e m o v e p h o s p h o r u s . I n a d d i t i o n , t h e f a c t t h a t a m e t h o d s u c h a s t h i s h a d t o b e d e v e l o p e d , i n d i c a t e s t h e n e e d f o r a p r e d i c t i v e m o d e l f o r p h o s p h o r u s r e m o v a l w h i c h c a n b e a p p l i e d t o C a n a d i a n t r e a t m e n t p l a n t s . I t w a s a s s u m e d t h a t t e m p e r a t u r e h a d n o e f f e c t o n t h e p h o s p h o r u s r e m o v a l c a p a b i l i t i e s o f t h e B i o - P p r o c e s s e s . T h i s w o u l d a p p e a r t o b e t h e g e n e r a l c o n s e n s u s a m o n g s t r e s e a r c h e r s . O l d h a m a n d Dew ( 1 9 7 9 ) p r e s e n t e d r e s u l t s f r o m p i l o t - s c a l e e x p e r i m e n t s w h i c h s h o w e d t h a t 9 0 p e r c e n t p h o s p h o r u s r e m o v a l w a s a c h i e v a b l e o v e r a t e m p e r a t u r e r a n g e f r o m 1 8 ° C t o 6"C. S e l l e t a l . ( 1 9 8 1 ) r e p o r t e d t h a t l a b s c a l e e x p e r i m e n t s - 74 -s h o w e d t h a t B i o - P r e m o v a l a t 5 ° C w a s a c t u a l l y s u p e r i o r t o t h a t a t 1 0 ° C a n d 1 5 ° C . O n t h i s b a s i s , i t w a s s u g g e s t e d b y t h e a u t h o r s t h a t B i o - P b a c t e r i a a r e p s y c h r o p h i l l i c . K a n g a n d H o r v a t i n ( 1 9 8 5 ) p r e s e n t e d r e s u l t s f r o m a f u l l - s c a l e B i o - P t e s t a t P o n t i a c , M i c h i g a n w h i c h s h o w e d t h a t B i o - P r e m o v a l w a s c o n s i s t e n t o v e r a t e m p e r a t u r e r a n g e f r o m 1 7 " C t o 1 0 ° C . I n t h i s t e s t , e f f l u e n t t o t a l p h o s p h o r u s c o n c e n t r a t i o n s o f l e s s t h a n 1 . 0 m g / L w e r e c o n s i s t e n t l y a c h i e v e d . T h e p r e d i c t i o n o f o x y g e n r e q u i r e m e n t s f o r t h e B i o - P p r o c e s s r e q u i r e d a n a s s u m p t i o n r e g a r d i n g t h e a m o u n t o f B O D s t a b i l i z a t i o n a c h i e v e d i n t h e a n a e r o b i c z o n e . S i n c e e n e r g y f r o m p o l y p h o s p h a t e b r e a k d o w n i s u s e d t o s t o r e V F A ' s a s P H B , i t s t a n d s t o r e a s o n t h a t s o m e o f t h e o r i g i n a l i n f l u e n t B O D i s r e m o v e d i n t h e a n a e r o b i c z o n e . R a n d a l l e t a l . ( 1 9 8 7 ) r e p o r t t h a t v a r i o u s l a b a n d p i l o t s c a l e e x p e r i m e n t s w i t h t h e U C T p r o c e s s a c h i e v e d a n a e r o b i c z o n e s t a b i l i z a t i o n s f r o m 0 t o 5 0 p e r c e n t o f t h e t o t a l i n f l u e n t C O D . H o w e v e r , t h e y c o n c l u d e t h a t C O D r e d u c t i o n w a s p r i m a r i l y d u e t o t h e a c t i v i t y o f f e r m e n t i n g b a c t e r i a i n t h e a n a e r o b i c z o n e , r a t h e r t h a n t h e a c t i v i t y o f B i o - P b a c t e r i a . E x p e r i e n c e s a t W i n d s o r a n d K e l o w n a , w h e r e p o o r B i o - P r e m o v a l w a s e n c o u n t e r e d w i t h o u t V F A a d d i t i o n t o t h e a n a e r o b i c z o n e , s u g g e s t t h a t m i n i m a l f e r m e n t a t i o n w a s i n f a c t a c h i e v e d i n t h e a n a e r o b i c z o n e o f t h e b i o r e a c t o r . F e r m e n t a t i o n i n t h e a n a e r o b i c z o n e i s l i k e l y d e p e n d e n t u p o n s e w a g e c h a r a c t e r i s t i c s ( d e g r e e o f s e p t i c i t y ) , r e t e n t i o n t i m e a n d t e m p e r a t u r e . T h e r e f o r e , f o r t h e p u r p o s e s o f t h i s s t u d y i t w a s a s s u m e d t h a t n e i t h e r f e r m e n t a t i o n - 75 -nor BOD s t a b i l i z a t i o n occurs i n the anaerobic zone. Oxygen requirements were thus c a l c u l a t e d as the sum of carbonaceous and n i t r i f i c a t i o n demands minus the c o n t r i b u t i o n to carbonaceous m a t e r i a l d e g r a d a t i o n through d e n i t r i f i c a t i o n . Assumptions f o r oxygen requirement c a l c u l a t i o n s where n i t r i f i c a t i o n occurs, are as f o l l o w s : i ) Nitrogenous 0^ Demand (kg/d) = 4.57 x Mass of Ammonia N i t r i f i e d (Ekama and Marais, 1984) i i ) Oxygen Recovered through De-n i t r i f i c a t i o n (kg/d) = 2.86 x Mass o f N i t r a t e s D e n i t r i f i e d (Ekama and Marais, 1984) Other assumptions made i n the d e s i g n of the b i o r e a c t o r were: i ) Anaerobic HRT = 1.0 hours (nominal). As shown i n Tables 2.4 and 2.5, t h i s i s t y p i c a l f o r mainstream Bio-P removal processes. i i ) SRT f o r Bio-P b a c t e r i a growth = 6.5 days ( total;)'. As shown i n , T a b l e 2.5, t h i s i s t y p i c a l f o r the A/0 . ; process. I t - was assumed t h a t t h i s SRT was not temperature\dependent. - 76 -i i i ) SRT f o r n i t r i f i c a t i o n c a l c u l a t e d as per the f o l l o w i n g e q u a t i o n (adapted from B e n e f i e l d and R a n d a l l , 1980 and Ekama and Marais, 1984A): e = c , ^ 0 J > 2 _ ( 1 0 - 0 3 3 < T - 2 0 > > , l - f x t > - b 2 0 ( 1 . 1 2 3 ) * 1 - 2 0 ) ! - 1 1 Z KO + DO Z Where yuL^Q = n i t r i f i e r s p e c i f i c growth r a t e at 20°C =0.4 d " 1 ( B e n e f i e l d and R a n d a l l , 1980) DO = DO c o n c e n t r a t i o n i n b i o r e a c t o r (mg/L) K = h a l f s a t u r a t i o n c o n s t a n t ° =1.3 mg/L ( B e n e f i e l d and R a n d a l l , 1980) T = mixed l i q u o r temperature (°C) f ^ = unaerated sludge mass f r a c t i o n = e ndogenous decay c o e f f i c i e n t f o r n i t r i f i e r s at 20°C ( d - 1 ) =0.04 d " 1 (Ekama and Marais, 1984A) 6 c = SRT (sludge age) (days) i v ) Growth y i e l d c o e f f i c e n t (Y) = 0.6 mg VSS/mg B0D 5 (Daigger e t a l . , 1987) v) Endogenous decay c o e f f i c i e n t (k^) = 0.05 d ^ v i ) D e n i t r i f i c a t i o n r a t e k i n e t i c s as per the f o l l o w i n g e q u a t i o n (adapted from Ekama and Marais, 1984): & N = 0.0285 S, . + K 0 0 f T _ 2° X 0 b i 20 " anox Where = maximum mass of n i t r a t e which can be removed i n the anoxic zone (mg/L) - 7 7 -b i o d e g r a d a b l e C O D o f t h e i n f l u e n t t o t h e b i o r e a c t o r ( m g / L ) . T h i s w a s a s s u m e d t o b e e q u a l t o 80% o f t h e i n f l u e n t C O D ( E k a m a a n d M a r a i s , 1 9 8 4 ) . B 0 D 5 w a s c o n v e r t e d t o C O D b y m u l t i p l y i n g b y 2 . 5 . d e n i t r i f i c a t i o n r a t e a t 2 0 ° C 0 . 0 7 2 mg N 0 3 - N / m g V S S - d ( E k a m a a n d M a r a i s , 1 9 8 4 ) A r h e n i u s t e m p e r a t u r e c o e f f i c e n t 1 . 0 3 ( E k a m a a n d M a r a i s , 1 9 8 4 ) b i o r e a c t o r M L V S S ( m g / L ) n o m i n a l a n o x i c H R T m i x e d l i q u o r t e m p e r a t u r e ( ° C ) P r o c e d u r e s u s e d f o r t h e p r o c e s s d e s i g n o f t h e b i o r e a c t o r f o r p h o s p h o r u s r e m o v a l o n l y , w e r e s l i g h t l y d i f f e r e n t t h a n t h o s e u s e d f o r t h e d e s i g n f o r c o m b i n e d a m m o n i a a n d p h o s p h o r u s r e m o v a l . T h e r e f o r e , l i s t i n g s o f s t e p - b y - s t e p p r o c e d u r e s w i l l b e p r e s e n t e d f o r b o t h c a s e s . 3 . 3 . 4 . 1 P r o c e s s D e s i g n P r o c e d u r e f o r P h o s p h o r u s  R e m o v a l O n l y i ) A s s u m e S R T = 6 . 5 d a y s i i ) D e t e r m i n e i f n i t r i f i c a t i o n w i l l o c c u r o v e r t h e e x p e c t e d t e m p e r a t u r e r a n g e o f t h e w a s t e w a t e r , b y c a l c u l a t i n g t h e r e q u i r e d S R T f o r n i t r i f i c a t i o n ( s e e p r e v i o u s e q u a t i o n ) . S b i = K 2 0 * V = X a n o x ~ T - 78 -i i i ) I f the c a l c u l a t e d SRT f o r n i t r i f i c a t i o n i s l e s s than 6.5 days w i t h i n the expected temperature range, then n i t r i f i c a t i o n i s l i k e l y t o occur d u r i n g at l e a s t p a r t o f the year and hence, an anoxic zone i s r e q u i r e d . I f the SRT i s g r e a t e r than 6.5 days an anoxic zone i s not r e q u i r e d . T h e r e f o r e , proceed to step x ) . i v ) C a l c u l a t e the e f f l u e n t BOD 5 (Se) «, _ K (1 + k, e — — 9 1 ( M e t c a l f & Eddy, 1979) (9 c ( Y k - k d ) - 1) Where K = h a l f v e l o c i t y constant S = 60 mg/L k = maximum r a t e of s u b s t r a t e u t i l i z a t i o n = 5 d " 1 v) Assume e =1.0 hours. Go back t o step i i ) anox c ' v i ) C a l c u l a t e b i o r e a c t o r MLVSS: x = 9 c ( S i - Se) Y (6 - e ) (1 + k, 0 ) v anaer' y d c' Where 9 = t o t a l b i o r e a c t o r nominal HRT (hours) Si,Se = i n f l u e n t and e f f l u e n t BOD,. v i i ) Assume a r a t i o f o r MLVSS/MLSS ( t y p i c a l l y 0.7) v i i i ) C a l c u l a t e b i o r e a c t o r MLSS i x ) C a l c u l a t e the s o l i d s l o a d i n g on the e x i s t i n g 2 secondary c l a r i f i e r . I f t h i s exceeds 100 kg/m d (Me t c a l f and Eddy, 1979) at average flow c o n d i t i o n s , i n c r e a s e the s i z e of the b i o r e a c t o r and r e t u r n t o step i i ) . - 79 -x ) D e t e r m i n e i f t h e a n o x i c z o n e s i z e i s s u f f i c i e n t t o d e n i t r i f y t h e e n t i r e m a s s o f n i t r a t e s b e i n g r o u t e d t o i t . T h i s i n v o l v e s t h e c a l c u l a t i o n o f t h e m a x i m u m m a s s o f n i t r a t e w h i c h c a n b e d e n i t r i f i e d i n t h e a n o x i c z o n e ( & N ) a n d c o m p a r i n g i t t o t h e m a s s o f n i t r a t e e n t e r i n g t h e z o n e . T h e m a s s o f n i t r a t e i s c a l c u l a t e d u s i n g a m a s s b a l a n c e a p p r o a c h a n d a s s u m i n g 100% n i t r i f i c a t i o n . I f t h e s i z e i s a d e q u a t e p r o c e e d t o t h e n e x t s t e p . I f t h e s i z e i s i n a d e q u a t e , r e t u r n t o s t e p i v ) a n d a s s u m e a l a r g e r a n o x i c z o n e s i z e . x i ) C a l c u l a t e WAS p r o d u c t i o n : d X = X V d t 9 c W h e r e d X = WAS p r o d u c t i o n ( k g / d ) d t 3 V = t o t a l r e a c t o r v o l u m e (m ) x i i ) A s s u m e a n a c h i e v a b l e e f f l u e n t S P c o n c e n t r a t i o n . x i i i ) C a l c u l a t e t h e r e q u i r e d p e r c e n t a g e o f p h o s p h o r u s i n t h e WAS t o a c h i e v e t h e a s s u m e d e f f l u e n t S P c o n c e n t r a t i o n . I f t h i s i s g r e a t e r t h a n 8.5% ( V S S b a s i s ) , r e t u r n t o s t e p x i i ) . - 8 0 -x i v ) A s s u m e a n a c h i e v a b l e e f f l u e n t s u s p e n d e d s o l i d s c o n c e n t r a t i o n f o r t h e s e c o n d a r y c l a r i f i e r s . G e n e r a l l y , t h i s i s b a s e d o n t h e p e r f o r m a n c e o f t h e e x i s t i n g c l a r i f i e r s ( i f a n y a r e p r e s e n t ) . x v ) C a l c u l a t e t h e t o t a l p h o s p h o r u s i n t h e e f f l u e n t u s i n g t h e f o l l o w i n g e q u a t i o n : T P e f f " S P e f f + ( * - P ) 1 0 0 W h e r e T P f f = e f f l u e n t t o t a l p h o s p h o r u s ( m g / L ) S P f f = e f f l u e n t s o l u b l e p h o s p h o r u s ( m g / L ) e ( f r o m s t e p x i i ) % P = p e r c e n t p h o s p h o r u s i n t h e WAS (%) ( f r o m s t e p x i i i ) V S S f f = V S S i n t h e e f f l u e n t ( m g / L ) e ( f r o m s t e p x i v ) I f T P e f f e x c e e d s t h e r e q u i r e d s t a n d a r d , c h e m i c a l a d d i t i o n o r e f f l u e n t f i l t r a t i o n s h o u l d b e a d d e d t o t h e p r o c e s s . x v i ) C a l c u l a t e o x y g e n d e m a n d a n d c o m p a r e t o t h e r a t e d c a p a c i t y o f e x i s t i n g a i r s u p p l y e q u i p m e n t ( f o r e x i s t i n g s e c o n d a r y p l a n t s ) o r t o t h e r a t e d c a p a c i t y o f a i r s u p p l y e q u i p m e n t f o r a n e q u i v a l e n t c h e m i c a l r e m o v a l p l a n t ( f o r p l a n t s n o t h a v i n g s e c o n d a r y t r e a t m e n t ) . - 8 1 -3 . 3 . 4 . 2 P r o c e s s D e s i g n P r o c e d u r e f o r C o m b i n e d  A m m o n i a a n d P h o s p h o r u s R e m o v a l i ) A s s u m e 8 „ = 1 . 0 h o u r s a n d 0 , „ = 1 . 0 h o u r s ' a n a e r a n o x i i ) C a l c u l a t e t h e r e q u i r e d S R T f o r n i t r i f i c a t i o n o v e r t h e e x p e c t e d r a n g e o f w a s t e w a t e r t e m p e r a t u r e s f o r t h e m o n t h s i n w h i c h a m m o n i a r e m o v a l i s r e q u i r e d . i i i ) C a l c u l a t e t h e d e s i g n S R T b y m u l t i p l y i n g t h e a c t u a l S R T b y a f a c t o r o f s a f e t y . E k a m a a n d M a r a i s ( 1 9 8 4 A ) r e c o m m e n d a f a c t o r o f s a f e t y o f 1 . 2 5 . i v ) C a l c u l a t e t h e e f f l u e n t B 0 D 5 a n d t h e b i o r e a c t o r M L V S S . v ) A s s u m e a r a t i o f o r M L V S S / M L S S . v i ) C a l c u l a t e t h e b i o r e a c t o r M L S S . v i i ) C a l c u l a t e t h e s o l i d s l o a d i n g o n t h e s e c o n d a r y 2 c l a r i f i e r . I f t h i s e x c e e d s 1 0 0 k g / m d a t a v e r a g e f l o w c o n d i t i o n s , i n c r e a s e t h e s i z e o f t h e b i o r e a c t o r a n d r e t u r n t o s t e p i i ) . - 82 -v i i i ) D e t e r m i n e i f t h e a n o x i c z o n e s i z i n g i s s u f f i c i e n t t o d e n i t r i f y t h e e n t i r e m a s s o f n i t r a t e s b e i n g r o u t e d t o i t . A g a i n , t h e m a s s o f n i t r a t e s i s c a l c u l a t e d u s i n g a m a s s b a l a n c e a p p r o a c h a n d a s s u m i n g 100% n i t r i f i c a t i o n . i x ) A s p e r s t e p s x i ) t o x v i ) i n t h e d e s i g n p r o c e d u r e f o r p h o s p h o r u s r e m o v a l o n l y . 3 . 3 . 5 S e c o n d a r y C l a r i f i e r s C o n v e r s i o n o f e x i s t i n g s e c o n d a r y p l a n t s t o m a i n s t r e a m B i o - P p l a n t s s h o u l d i m p r o v e t h e p e r f o r m a n c e o f t h e e x i s t i n g s e c o n d a r y c l a r i f i e r s . W a n n e r e t a l . ( 1 9 8 7 ) s u g g e s t t h a t t h e p l a c e m e n t o f a n a n a e r o b i c o r a n o x i c z o n e a t t h e f r o n t - e n d o f t h e b i o r e a c t o r c a n i m p r o v e s l u d g e s e t t l e a b i l i t y t h r o u g h t h e s u p p r e s s i o n o f f i l a m e n t o u s o r g a n i s m g r o w t h . I m p r o v e d p e r f o r m a n c e m a y n o t b e r e a l i z e d i n s i d e s t r e a m p r o c e s s e s ( e . g . P h o s t r i p ) a s W a n n e r e t a l . n o t e t h a t t h e g r o w t h o f f i l a m e n t o u s o r g a n i s m s i s s u p p r e s s e d o n l y w h e r e t h e m a j o r i t y o f t h e s u b s t r a t e i n t h e w a s t e w a t e r i s c o n s u m e d u n d e r a n a e r o b i c c o n d i t i o n s . F o r m a i n s t r e a m B i o - P p r o c e s s e s i t w a s t h e r e f o r e d e c i d e d t o s i z e t h e c l a r i f i e r s i n a c c o r d a n c e w i t h d e s i g n g u i d e l i n e s f o r c o n v e n t i o n a l s e c o n d a r y c l a r i f i e r s . D u e t o t h e - 83 -a p p a r e n t s u p e r i o r s e t t l i n g p r o p e r t i e s o f B i o - P s l u d g e , i t w a s f e l t t h a t t h i s p r o v i d e d a n a d d e d f a c t o r o f s a f e t y t o e n s u r e t h a t e f f l u e n t p h o s p h o r u s s t a n d a r d s w e r e m e t . T h e r e f o r e , b a s e d o n g u i d e l i n e s s u g g e s t e d b y M e t c a l f a n d E d d y ( 1 9 7 9 ) , t h e f o l l o w i n g s i z i n g c r i t e r i a w e r e e s t a b l i s h e d : 3 2 . . l ) O v e r f l o w R a t e <24 m / m d ( a t a v e r a g e f l o w c o n d i t i o n s ) . . . . 2 . . i i ) S o l i d s L o a d i n g < 1 0 0 k g / m d ( a t a v e r a g e f l o w c o n d i t i o n s ) U S E P A g u i d e l i n e s ( U S E P A , 1 9 8 7 ) s u g g e s t t h a t s e c o n d a r y c l a r i f i e r s f o r c o m b i n e d b i o l o g i c a l / c h e m i c a l s l u d g e s s h o u l d b e 3 2 s i z e d f o r o v e r f l o w r a t e s o f 24 m / m d a t a v e r a g e f l o w c o n d i t i o n s . S i n c e t h i s i s t h e s a m e a s M e t c a l f a n d E d d y ' s g u i d e l i n e s f o r b i o l o g i c a l s l u d g e s , i t w a s a s s u m e d t h a t t h e r e w a s n o d i f f e r e n c e i n t h e s e t t l i n g c h a r a c t e r i s t i c s o f t h e t w o s l u d g e s a n d h e n c e , n o d i f f e r e n c e i n t h e s i z e o f c l a r i f i e r s r e q u i r e d f o r m a i n s t r e a m B i o - P a n d c h e m i c a l p h o s p h o r u s r e m o v a l p r o c e s s e s . F u r t h e r e v i d e n c e o f t h e v a l i d i t y o f t h i s a s s u m p t i o n w a s p r o v i d e d b y T e t r a u l t e t a l . ( 1 9 8 6 ) w h o , i n a r e v i e w o f B i o - P t e c h n o l o g y , c o n c l u d e d t h a t c o n v e n t i o n a l l y d e s i g n e d s e c o n d a r y c l a r i f i e r s s h o u l d b e a b l e t o a c h i e v e e f f l u e n t T S S c o n c e n t r a t i o n s o f 1 0 m g / L i n a B i o - P o p e r a t i o n . F o r p l a n t s h a v i n g e x i s t i n g s e c o n d a r y t r e a t m e n t , R A S f l o w r a t e s w e r e c a l c u l a t e d b y a s s u m i n g c l a r i f i e r u n d e r f l o w c o n c e n t r a t i o n s e q u a l t o t h e e x i s t i n g c o n c e n t r a t i o n s . F o r p l a n t s n o t h a v i n g e x i s t i n g b i o r e a c t o r s , R A S c o n c e n t r a t i o n s o f 1 0 , 0 0 0 m g / L w e r e a s s u m e d . - 84 -R A S p u m p r e q u i r e m e n t s w e r e d e f i n e d a s f o l l o w s : i ) A m i n i m u m o f t w o p u m p s , e a c h b e i n g c a p a b l e o f p r o v i d i n g a f l o w e q u a l t o t h e p l a n t i n f l u e n t f l o w a t a v e r a g e c o n d i t i o n s , s h o u l d b e a v a i l a b l e . i i ) P u m p i n g s y s t e m s s h o u l d n o t c r e a t e t h e p o t e n t i a l f o r e x c e s s i v e DO e n t r a i n m e n t . S c r e w p u m p s e x p o s e d t o t h e a t m o s p h e r e w e r e d e e m e d u n a c c e p t a b l e . 3 . 3 . 6 WAS T h i c k e n i n g B i o - P r e m o v a l h a s n o e f f e c t o n t h e d e s i g n a n d o p e r a t i o n o f WAS t h i c k e n e r s . F o r n e w f a c i l i t i e s , t h i c k e n e r s i z e s m a y b e s m a l l e r f o r B i o - P p l a n t s r e l a t i v e t o c h e m i c a l p l a n t s s i n c e WAS v o l u m e s w i l l t y p i c a l l y b e s m a l l e r . T h e o n l y t y p e s o f WAS t h i c k e n e r s e n c o u n t e r e d i n t h i s r e s e a r c h w e r e d i s s o l v e d a i r f l o t a t i o n ( D A F ) u n i t s a n d c e n t r i f u g e s . A s s u m e d d e s i g n p a r a m e t e r s f o r t h e c h e c k i n g o f e x i s t i n g u n i t s , t h e s i z i n g o f n e w u n i t s a n d t h e p r e p a r a t i o n o f m a t e r i a l b a l a n c e s a r e l i s t e d b e l o w : i ) D A F U n i t ( M e t c a l f a n d E d d y , 1 9 7 9 ) 2 S o l i d s L o a d i n g = 5 0 k g / m d T h i c k e n e d S l u d g e S S = 4% S u b n a t a n t B O D 5 = 2 5 0 m g / L S u b n a t a n t T S S = 3 0 0 m g / L - 8 5 -i i ) C e n t r i f u g e T h i c k e n e d S l u d g e S S = 4% ( S t a n l e y A s s o c i a t e s , 1 9 8 6 ) R e c y c l e F l o w BODp. = 1 , 0 0 0 m g / L ( M e t c a l f a n d E d d y , 1 9 7 9 ) R e c y l e F l o w T S S = 2 , 0 0 0 m g / L ( M e t c a l f a n d E d d y , 1 9 7 9 ) 3 . 3 . 7 S l u d g e S t a b i l i z a t i o n S l u d g e s t a b i l i z a t i o n m e t h o d s e m p l o y e d i n t h e p l a n t s s t u d i e d i n c l u d e d a n a e r o b i c a n d a e r o b i c d i g e s t i o n . A n a e r o b i c d i g e s t i o n w a s u s e d i n s i x o u t o f t h e n i n e p l a n t s s t u d i e d . T h e M i l t o n p l a n t u s e s a n a e r o b i c d i g e s t i o n f o r p r i m a r y s l u d g e a n d a e r o b i c d i g e s t i o n f o r W A S . N o f o r m o f s t a b i l i z a t i o n i s c a r r i e d o u t a t t h e W i n d s o r L i t t l e R i v e r p l a n t , t h e E l m i r a p l a n t o r t h e W e l l e s l e y e x t e n d e d a e r a t i o n p l a n t . T h e u s e o f a n a e r o b i c a n d a e r o b i c d i g e s t i o n h a s g e n e r a l l y b e e n r e j e c t e d f o r n e w B i o - P i n s t a l l a t i o n s s i n c e t h e s t o r e d p h o s p h o r u s i s r e l e a s e d f r o m t h e WAS u n d e r b o t h c o n d i t i o n s . T r a d i t i o n a l l y , t h e a p p r o a c h t o m a n a g i n g B i o - P s l u d g e s h a s b e e n t o p r e v e n t p h o s p h o r u s r e l e a s e . H o n g e t a l . ( 1 9 8 1 ) r e c o m m e n d b e l t o r v a c u u m f i l t r a t i o n f o r t h e d e w a t e r i n g o f A / 0 p r o c e s s s l u d g e s . B a r n a r d ( 1 9 8 3 ) r e c o m m e n d s t h e u s e o f f l o t a t i o n t h i c k e n i n g , b e l t f i l t e r p r e s s i n g a n d / o r l a n d - 8 6 -a p p l i c a t i o n f o r B i o - P s l u d g e s . T h e K e l o w n a p l a n t u t i l i z e s d i s s o l v e d a i r f l o t a t i o n f o r t h i c k e n i n g o f t h e w a s t e a c t i v a t e d s l u d g e , f o l l o w e d b y c o m p o s t i n g ( L e s l i e , 1 9 8 5 ) . H o w e v e r , f o r r e t r o f i t o f p l a n t s u s i n g a n a e r o b i c o r a e r o b i c d i g e s t i o n , t h e i n s t a l l a t i o n o f n e w s y s t e m s f o r t h e t r e a t m e n t o f WAS w i l l r e s u l t i n s i g n i f i c a n t c a p i t a l c o s t s . I n a d d i t i o n , i n p l a n t s w h i c h r e c o v e r m e t h a n e g a s f r o m a n a e r o b i c d i g e s t i o n , s u b s t a n t i a l o p e r a t i n g c o s t s w o u l d b e i n c u r r e d t h r o u g h t h e p u r c h a s e o f n a t u r a l g a s t o m a k e - u p l o s t m e t h a n e p r o d u c t i o n . F u r t h e r m o r e , s o m e p r o v i n c e s h a v e r e g u l a t i o n s r e g a r d i n g t h e l a n d a p p l i c a t i o n o f u n d i g e s t e d s l u d g e . I n O n t a r i o , u n d i g e s t e d s l u d g e s c a n n o t b e a p p l i e d t o a g r i c u l t u r a l l a n d s ( O n t a r i o M i n i s t r i e s o f A g r i c u l t u r e , E n v i r o n m e n t a n d H e a l t h , 1 9 8 6 ) . I n A l b e r t a , a p p l i c a t i o n r a t e s f o r u n d i g e s t e d s l u d g e s a r e c o n s i d e r a b l y l e s s t h a n f o r d i g e s t e d s l u d g e s ( A l b e r t a E n v i r o n m e n t , 1 9 8 2 ) . I n S a s k a t c h e w a n , d r a f t d i s p o s a l g u i d e l i n e s i n d i c a t e t h a t s e w a g e s l u d g e c a n b e a p p l i e d t o a g r i c u l t r u a l l a n d s p r o v i d e d t h a t i t i s b i o l o g i c a l l y s t a b i l i z e d p r i o r t o a p p l i c a t i o n ( S t a n l e y A s s o c i a t e s , 1 9 8 6 A ) . T h e r e f o r e , t h e e l i m i n a t i o n o f d i g e s t i o n p r o c e s s e s t o a c c o m m o d a t e B i o - P r e m o v a l c o u l d r e s u l t i n s i g n i f i c a n t c o s t s a n d o p e r a t i o n a l c h a n g e s , e s p e c i a l l y i f l a n d a p p l i c a t i o n o f s l u d g e i s p r a c t i s e d . A s a r e s u l t , c o n s i d e r a t i o n w a s g i v e n t o t h e c o n t i n u e d u s e o f a n a e r o b i c a n d a e r o b i c d i g e s t i o n f o r W A S , c o m b i n e d w i t h c h e m i c a l t r e a t m e n t o f d i g e s t o r s u p e r n a t a n t . - 8 7 -T h i s m e t h o d o f h a n d l i n g w a s t e a c t i v a t e d s l u d g e h a s b e e n d i s c u s s e d a n d e x p e r i m e n t e d w i t h b y o t h e r r e s e a r c h e r s . H o n g e t a l . ( 1 9 8 1 ) r e c o m m e n d s l i m e p r e c i p i t a t i o n o f s o l u b l e p h o s p h o r u s s h o u l d d i g e s t o r s u p e r n a t a n t s t r e a m s c o n t a i n g r e a t e r t h a n 1 0 0 m g / L o f s o l u b l e p h o s p h o r u s . M u r a k a m i e t a l . ( 1 9 8 7 ) s u c c e s s f u l l y p r e v e n t e d p h o s p h o r u s r e l e a s e i n a c o m b i n e d p r i m a r y / w a s t e a c t i v a t e d s l u d g e , b y a d d i n g a n a l u m i n u m c o a g u l a n t s e p a r a t e l y t o t h e s l u d g e s p r i o r t o t h e i r c o m b i n e d g r a v i t y t h i c k e n i n g , a n a e r o b i c d i g e s t i o n a n d f i l t e r p r e s s d e w a t e r i n g . I t w a s d e t e r m i n e d t h a t a d o s e o f 5 - 6 g A l / k g T S S r e s u l t e d i n t o t a l p h o s p h o r u s c o n c e n t r a t i o n s o f l e s s t h a n 1 . 0 m g / L b e i n g r e t u r n e d v i a t h e f i l t e r p r e s s s u p e r n a t a n t . S h o u l d c h e m i c a l t r e a t m e n t o f s u p e r n a t a n t / f i l t r a t e s t r e a m s b e s e l e c t e d , i t i s n e c e s s a r y t o e s t i m a t e t h e a m o u n t o f p h o s p h o r u s w h i c h w i l l b e r e l e a s e d d u r i n g s l u d g e p r o c e s s i n g . D e a k y n e e t a l . ( 1 9 8 4 ) r e p o r t s t h a t 59% o f t h e t o t a l p h o s p h o r u s t a k e n u p b y a p i l o t - s c a l e A / 0 p r o c e s s , w a s r e l e a s e d a f t e r 9 6 h o u r s o f a n a e r o b i c d i g e s t i o n . M u r a k a m i e t a l . ( 1 9 8 7 ) p r e s e n t s i m i l a r r e s u l t s f r o m a f u l l - s c a l e t e s t c a r r i e d o u t o n t h e 9 0 0 0 3 m / d S h i n j i k o - t o b u p l a n t i n J a p a n . A p p r o x i m a t e l y 60% o f t h e p h o s p h o r u s r e m o v e d i n t h e b i o r e a c t o r w a s r e l e a s e d d u r i n g a n a e r o b i c d i g e s t i o n . T h e s e f i g u r e s c o r r e s p o n d w e l l w i t h t h o s e p r e s e n t e d b y L e v i n a n d D e l i a S a l l a ( 1 9 8 7 ) w h o n o t e t h a t r o u g h l y t w o - t h i r d s o f t h e p h o s p h o r u s t a k e n u p u n d e r a e r o b i c c o n d i t i o n s i s r e l e a s e d i n t h e s t r i p p e r i n t h e P h o s t r i p p r o c e s s . T h e r e f o r e , - 8 8 -b a s e d o n t h e s e r e s u l t s , i t w a s c o n s e r v a t i v e l y a s s u m e d t h a t p h o s p h o r u s r e l e a s e i n a n a n a e r o b i c d i g e s t o r w a s e q u a l t o 1 0 0 p e r c e n t o f t h e p h o s p h o r u s i n t h e V S S d e s t r o y e d , p l u s 6 0 p e r c e n t o f t h e p h o s p h o r u s i n t h e r e m a i n i n g V S S . O t h e r d e s i g n p a r a m e t e r s u s e d i n c o m p u t i n g m e t h a n e p r o d u c t i o n a n d s l u d g e a n d s u p e r n a t a n t f l o w s a r e l i s t e d b e l o w . E x i s t i n g o p e r a t i o n s d a t a w a s u s e d i n p l a c e o f t h e s e p a r a m e t e r s w h e n i t w a s a v a i l a b l e f r o m t h e i n d i v i d u a l p l a n t s : i ) A n a e r o b i c D i q e s t o r s V S S R e d u c t i o n = 65% ( R e y n o l d s , 1 9 8 2 ) 3 M e t h a n e P r o d u c t i o n = 1 . 0 5 m / k g V S S d e s t r o y e d ( R e y n o l d s , 1 9 8 2 ) F o r t w o - s t a g e d i g e s t o r s : - S u p e r n a t a n t T S S = 5 , 0 0 0 m g / L ( R e y n o l d s , 1 9 8 2 ) S u p e r n a t a n t B 0 D 5 = 2 , 0 0 0 m g / L ( R e y n o l d s , 1 9 8 2 ) - U n d e r f l o w S S = 8% ( R e y n o l d s , 1 9 8 2 ) i i ) A e r o b i c D i g e s t i o n V S S R e d u c t i o n = 50% ( M e t c a l f a n d E d d y , 1 9 7 9 ) O x y g e n R e q u i r e m e n t = 2 . 3 k g / k g V S S d e s t r o y e d ( M e t c a l f a n d E d d y , 1 9 7 9 ) - 8 9 -C o m p o s t i n g w a s c o n s i d e r e d a s a n a l t e r n a t e m e t h o d f o r s l u d g e s t a b i l i z a t i o n . T h i s i s a v e r y p r a c t i c a l m e t h o d o f h a n d l i n g B i o - P s l u d g e s s i n c e i t d o e s n o t i n v o l v e r e c y c l i n g p h o s p h o r u s - r i c h s u p e r n a t a n t s t r e a m s b a c k t o t h e p l a n t . I n a d d i t i o n , c o m p o s t i n g a p p e a r s t o b e a n a c c e p t a b l e m e t h o d o f s t a b i l i z i n g WAS i n B . C . , A l b e r t a , S a s k a t c h e w a n a n d O n t a r i o a n d h e n c e , a l l o w s f o r l a n d a p p l i c a t i o n o f t h e c o m p o s t e d s l u d g e . H o w e v e r , t h e e v a l u a t i o n o f a c o m p o s t i n g o p e r a t i o n f o r e a c h i n d i v i d u a l p l a n t n e c e s s i t a t e s t h e l o c a t i o n o f a s i t e a n d a s u p p l y o f b u l k m a t e r i a l ( e . g . w o o d c h i p s , g r a s s c u t t i n g s ) t o m i x w i t h t h e s l u d g e . T h i s w a s d e e m e d t o b e o u t s i d e t h e s c o p e o f t h i s s t u d y a n d t h e r e f o r e , t h e u s e o f c o m p o s t i n g i s d i s c u s s e d i n g e n e r a l t e r m s o n l y , w h e r e a p p l i c a b l e . 3 . 3 . 8 S l u d g e D e w a t e r i n g S l u d g e d e w a t e r i n g m e t h o d s e m p l o y e d b y t h e p l a n t s s t u d i e d i n c l u d e d s l u d g e l a g o o n s , f i l t e r p r e s s e s a n d c e n t r i f u g e s . O p e r a t i n g p a r a m e t e r s r e q u i r e d t o c a l c u l a t e s l u d g e v o l u m e s , a n d r e c y c l e f l o w s a n d c o m p o s i t i o n s w e r e o b t a i n e d d i r e c t l y f r o m t h e p l a n t s . I t w a s a s s u m e d t h a t s i g n i f i c a n t p h o s p h o r u s r e l e a s e d i d n o t o c c u r i n t h e f i l t e r p r e s s e s a n d c e n t r i f u g e s . I t w a s a l s o a s s u m e d t h a t l i t t l e a d d i t i o n a l p h o s p h o r u s r e l e a s e o c c u r r e d i n l a g o o n s f r o m s l u d g e w h i c h h a d b e e n p r e v i o u s l y d i g e s t e d . - 9 0 -I n o n e c a s e i t w a s r e q u i r e d t o c r e a t e a d d i t i o n a l s l u d g e l a g o o n v o l u m e . T h i s w a s d o n e b y a s s u m i n g a s o l i d s l o a d i n g o f 3 7 k g / m 3 y r ( U S E P A , 1 9 7 4 ) . F o r i n t e r m i t t e n t l y o p e r a t e d d e w a t e r i n g e q u i p m e n t ( e . g . f i l t e r p r e s s e s , c e n t r i f u g e s ) , t h e s t o r a g e o f B i o - P s l u d g e b e t w e e n o p e r a t i n g s h i f t s m a y c r e a t e t h e p o t e n t i a l f o r p h o s p h o r u s r e l e a s e . T h e r e f o r e , o p e r a t i o n a l c h a n g e s m a y b e r e q u i r e d t o p r e v e n t t h i s f r o m o c c u r r i n g . P o s s i b l e m e t h o d s o f a l l e v i a t i n g t h i s p r o b l e m a r e i n t e r m i t t e n t s l u d g e w a s t i n g c o i n c i d i n g w i t h d e w a t e r i n g o p e r a t i o n s , o r c h e m i c a l a d d i t i o n t o t h e s l u d g e s t o r a g e t a n k . O f t e n c h e m i c a l s a r e a d d e d t o t h i s t a n k f o r s l u d g e c o n d i t i o n i n g p u r p o s e s a n d m a y , d e p e n d i n g o n t h e t y p e , b e s u f f i c i e n t f o r t h e c o n t r o l o f p h o s p h o r u s r e l e a s e . 3 . 3 . 9 E f f l u e n t F i l t r a t i o n S o m e p a s t a s s e s s m e n t s o f B i o - P t e c h n o l o g y h a v e s p e c i f i e d t h e n e e d f o r e f f l u e n t f i l t r a t i o n t o a c h i e v e e f f l u e n t T P c o n c e n t r a t i o n s l e s s t h a n 1 . 0 m g / L ( C a n v i r o e t a l . , 1 9 8 6 , E v a n s a n d C r a w f o r d , 1 9 8 5 ) . T h e r a t i o n a l e b e h i n d t h i s i s t h e h i g h c o n c e n t r a t i o n o f p h o s p h o r u s c o n t a i n e d i n t h e b i o l o g i c a l s o l i d s . E v a n s a n d C r a w f o r d c o r r e c t l y n o t e t h a t f o r a s l u d g e c o n t a i n i n g 5% p h o s p h o r u s b y w e i g h t , a n e f f l u e n t s u s p e n d e d s o l i d s c o n c e n t r a t i o n o f 1 5 m g / L w i l l y i e l d a n e f f l u e n t p a r t i c u l a t e p h o s p h o r u s c o n c e n t r a t i o n o f 0 . 7 5 m g / L . T h e r e f o r e s h o u l d e f f l u e n t S P c o n c e n t r a t i o n s e x c e e d 0 . 2 5 m g / L , t h e e f f l u e n t T P c o n c e n t r a t i o n w i l l e x c e e d t h e r e q u i r e d l i m i t . - 9 1 -W h i l e t h i s r e a s o n i n g e m p h a s i z e s t h e n e e d f o r e f f e c t i v e s o l i d s s e p a r a t i o n i n a B i o - P p r o c e s s , t h r e e c o m m e n t s a r e w a r r a n t e d . F i r s t l y , a l l o f t h e p h o s p h o r u s r e m o v e d i n a n y w a s t e w a t e r t r e a t m e n t p r o c e s s , b i o l o g i c a l o r c h e m i c a l , i s v i a s o l i d s s e p a r a t i o n . P h o s p h o r u s c o n c e n t r a t i o n s i n B i o - P s l u d g e s w i l l n o t b e s i g n i f i c a n t l y h i g h e r t h a n i n c o m b i n e d b i o l o g i c a l / c h e m i c a l s l u d g e s . F o r t h e s a m e a m o u n t o f p h o s p h o r u s r e m o v e d , i n c r e a s e d s o l i d s p r o d u c t i o n t h r o u g h c h e m i c a l p r e c i p i t a t i o n w i l l b e o f f s e t b y i n c r e a s e d b i o l o g i c a l s o l i d s p r o d u c t i o n f r o m t h e a d d i t i o n a l B O D l o a d i n g ( f r o m t h e f e r m e n t e r o p e r a t i o n ) o n t h e B i o - P b i o r e a c t o r . T h e r e f o r e , c l a r i f i e r p e r f o r m a n c e i s o f n o l e s s i m p o r t a n c e t o a c h e m i c a l p h o s p h o r u s r e m o v a l o p e r a t i o n t h a n t o a B i o - P p r o c e s s . S e c o n d l y , o p e r a t i n g e x p e r i e n c e w i t h p r o p e r l y d e s i g n e d B i o - P p l a n t s s h o w s t h a t e f f l u e n t T P c o n c e n t r a t i o n s o f l e s s t h a n 1 . 0 m g / L c a n b e c o n s i s t e n t l y m a i n t a i n e d w i t h o u t e f f l u e n t f i l t r a t i o n . T e t r e a u l t e t a l . ( 1 9 8 6 ) , K a n g a n d H o r v a t i n ( 1 9 8 5 ) , a n d L e v i n a n d D e l i a S a l l a ( 1 9 8 7 ) a l l p r e s e n t r e s u l t s w h i c h s h o w t h i s t o b e t r u e . T h i r d l y , s h o u l d e f f l u e n t c o n c e n t r a t i o n s h a p p e n t o e x c e e d 1 . 0 m g / L , i t i s m o r e c o s t e f f e c t i v e t o a d d a s m a l l q u a n t i t y o f c h e m i c a l ( a l u m o r i r o n s a l t s ) t o t h e b i o r e a c t o r t o r e m o v e a n y r e m a i n i n g s o l u b l e p h o s p h o r u s . S t e v e n s ( 1 9 8 7 ) r e p o r t s - 92 -o n t h e s u c c e s s f u l u s e o f t h i s p r a c t i c e a t K e l o w n a , w h e r e t h e a d d i t i o n o f 1 5 m g / L o f a l u m r e s u l t e d i n u n f i l t e r e d e f f l u e n t T P c o n c e n t r a t i o n s a v e r a g i n g 0 . 3 m g / L o v e r a n e i g h t m o n t h p e r i o d . T h e r e f o r e , i t w a s c o n c l u d e d t h a t e f f l u e n t f i l t e r s w e r e n o t r e q u i r e d t o a c h i e v e T P c o n c e n t r a t i o n s o f 1 . 0 m g / L . C e r t a i n l y i f e f f l u e n t s t a n d a r d s f o r T P w e r e l o w e r e d t o , s a y 0 . 5 m g / L , t h e n f i l t r a t i o n w o u l d b e r e q u i r e d . H o w e v e r , f i l t r a t i o n w o u l d a l s o b e r e q u i r e d f o r c h e m i c a l p h o s p h o r u s r e m o v a l . T h e r e f o r e , n o i n c r e m e n t a l e f f l u e n t f i l t r a t i o n r e q u i r e m e n t s w e r e i m p o s e d o n a B i o - P p r o c e s s o v e r a n d a b o v e t h o s e r e q u i r e d f o r a c h e m i c a l r e m o v a l p r o c e s s . A s a r e s u l t , d e s i g n c r i t e r i a f o r e f f l u e n t f i l t e r s w e r e n o t r e q u i r e d . 3 . 3 . 1 0 C h e m i c a l T r e a t m e n t I t w a s a s s u m e d t h a t a c o m p l e t e c h e m i c a l p h o s p h o r u s r e m o v a l s y s t e m w a s r e q u i r e d a s a b a c k - u p f o r e a c h B i o - P s y s t e m s i n c e t h e s u s c e p t i b i l i t y o f B i o - P p r o c e s s e s t o u p s e t c o n d i t i o n s i s r e l a t i v e l y u n k n o w n . D e s i g n o f t h e s e s y s t e m s w e r e n o t r e q u i r e d s i n c e n o i n c r e m e n t a l c o s t s w e r e i n v o l v e d . D e s i g n o f s y s t e m s f o r t h e c h e m i c a l t r e a t m e n t o f r e c y c l e s t r e a m s w a s r e q u i r e d w h e n a n a e r o b i c o r a e r o b i c d i g e s t i o n o f WAS w a s u s e d . L i m e w a s s e l e c t e d a s t h e o p t i m u m c h e m i c a l i n t h e s e c a s e s b e c a u s e o f t h e s m a l l f l o w s a s s o c i a t e d w i t h t h e - 9 3 -r e c y c l e s t r e a m s a n d t h e l o w c o s t o f l i m e r e l a t i v e t o a l u m i n u m a n d i r o n s a l t s . H y d r a t e d l i m e ( C a ( O H ) 2 ) w a s s e l e c t e d o v e r q u i c k l i m e ( C a O ) a s i t w a s d e e m e d t o b e m o r e e c o n o m i c f o r t h e q u a n t i t i e s i n v o l v e d ( H a r v e y , 1 9 8 8 ) . T h e l i m e a d d i t i o n s y s t e m c o n s i s t s o f a b u l k c h e m i c a l s t o r a g e t a n k ; a c h e m i c a l f e e d e r ; a m i x t a n k f o r m a k i n g a l i m e s l u r r y ; a h o l d i n g t a n k f o r m a i n t a i n i n g a t w o - d a y s u p p l y o f s l u r r y ; a c o m b i n e d r a p i d m i x / f l o c c u l a t i o n t a n k i n w h i c h t h e l i m e s l u r r y i s a d d e d t o t h e r e c y c l e s t r e a m ; a n d a c l a r i f i e r f o r s o l i d s s e p a r a t i o n . T h e e n t i r e s y s t e m i s l o c a t e d i n d o o r s . A s c h e m a t i c d r a w i n g o f t h e s y s t e m i s p r e s e n t e d i n F i g u r e 3 . 5 . D e s i g n c r i t e r i a f o r t h e i n d i v i d u a l p i e c e s o f e q u i p m e n t a r e a s f o l l o w s : i ) B u l k S t o r a g e B i n ( s ) a b o v e g r o u n d s t e e l t a n k s p r o v i d e 3 0 d a y s s t o r a g e a t a v e r a g e f l o w c o n d i t i o n s i i ) C h e m i c a l F e e d e r ( s ) - r o t a r y t y p e f e e d e r s i z e d t o p r o v i d e s u f f i c i e n t l i m e t o m a k e a 2 - d a y s u p p l y o f l i m e s l u r r y i n 8 h o u r s BULK STORAGE HOLDING TANK RAPID MIX/ FLOCCULATION TANK MIX WATER (SECONDARY EFFLUENT ETC.) MIX TANK RECYCLE STREAMS CLARIFIER EFFLUENT TO SLUDGE PROCESSING vo F I G U R E 3 . 5 - L I M E T R E A T M E N T P R O C E S S S C H E M A T I C - 9 5 -i i i ) M i x T a n k p r o v i d e 5 m i n u t e r e t e n t i o n t i m e a t a f e e d r a t e o f 0 . 0 1 7 m 3 w a t e r / k g l i m e ( U S E P A , 1 9 7 1 ) i v ) M i x T a n k M i x e r v e l o c i t y g r a d i e n t , G = 6 5 0 m / s . m v ) M i x T a n k P u m p s p r o v i d e 2 x 100% P D m e t e r i n g p u m p s s i z e d f o r 3 . 0 . 0 1 7 m w a t e r / k g l i m e a t a v e r a g e f l o w c o n d i t i o n s v i ) H o l d i n g T a n k - a b o v e g r o u n d s t e e l t a n k p r o v i d e 2 d a y s s l u r r y s t o r a g e a t a v e r a g e f l o w c o n d i t i o n s v i i ) H o l d i n g T a n k M i x e r 3 . . - p r o v i d e 4 W / m m i x i n g e n e r g y v i i i ) H o l d i n g T a n k P u m p s - p r o v i d e 2 x 100% P D m e t e r i n g p u m p s s i z e d f o r s l u r r y f e e d r a t e a t a v e r a g e c o n d i t i o n s i x ) R a p i d M i x / F l o c c u l a t i o n T a n k a n d M i x e r s a b o v e g r o u n d s t e e l t a n k - 9 6 -r a p i d m i x s e c t i o n s i z e d f o r 3 0 s e c o n d r e t e n t i o n t i m e a t a v e r a g e f l o w c o n d i t i o n s ( U S E P A , 1 9 7 1 ) r a p i d m i x m i x e r s i z e d f o r G = 6 5 0 m / s - m ( U S E P A , 1 9 7 1 ) f l o c c u l a t i o n s e c t i o n s i z e d f o r 4 . 5 m i n u t e r e t e n t i o n t i m e a t a v e r a g e f l o w c o n d i t i o n s ( U S E P A , 1 9 7 1 ) f l o c c u l a t i o n m i x e r s i z e d f o r G = 6 5 m / s - m ( U S E P A , 1 9 7 1 ) x ) C l a r i f i e r ( s ) 3 2 d e s i g n o v e r f l o w r a t e = 48 m / m d a t a v e r a g e f l o w c o n d i t i o n s ( U S E P A , 1 9 7 1 ) x i ) L i m e S l u d g e P u m p s - p r o v i d e 2 x 100% P D p u m p s s i z e d f o r s l u d g e f l o w a t a v e r a g e f l o w c o n d i t i o n s p u m p s s h o u l d b e c o n t r o l l e d b y a t i m e r C h e m i c a l d o s a g e r a t e s f o r p h o s p h o r u s r e m o v a l w i t h a l u m , f e r r i c c h l o r i d e a n d h y d r a t e d l i m e w e r e c a l c u l a t e d f o r i n c r e m e n t a l o p e r a t i n g c o s t c a l c u l a t i o n s a n d s i z i n g o f e q u i p m e n t f o r l i m e t r e a t m e n t o f r e c y c l e s t r e a m s . T h e f o l l o w i n g e q u a t i o n s w e r e u s e d : - 9 7 -i ) A l u m ( a d a p t e d f r o m P r e s t e d e t a l . , 1 9 7 7 ) A l u m D o s e ( m g / L ) = 1 4 . 3 - 3 . 3 W h e r e P = c o n c e n t r a t i o n o f S P t o b e r e m o v e d ( m g / L ) i i ) F e r r i c C h l o r i d e ( a d a p t e d f r o m P r e s t e d e t a l . , 1 9 7 7 ) F e C l 3 D o s e ( m g / L ) = 4 . 1 A P + 1 . 5 i i i ) H y d r a t e d L i m e C a ( O H ) 2 ( m g / L ) = 1 . 0 5 ( 0 . 7 4 A l k + 4 . 0 A P + 1 . 7 CC> 2) W h e r e A l k = a l k a l i n i t y o f u n t r e a t e d r e c y c l e s t r e a m ( m g / L C a C 0 3 ) C O = c o n c e n t r a t i o n o f C 0 2 i n r e c y c l e s t r e a m ( m g / L ) S l u d g e q u a n t i t i e s a s s o c i a t e d w i t h c h e m i c a l p h o s p h o r u s r e m o v a l w e r e c a l c u l a t e d a s f o l l o w s : i ) A l u m A l u m S l u d g e ( m g / L ) = 0 . 3 5 5 A l u m - 0 . 5 1 2 W h e r e A l u m = c o n c e n t r a t i o n o f a l u m a d d e d ( m g / L ) i i ) F e r r i c C h l o r i d e F e C l 3 S l u d g e ( m g / L ) = . 9 8 2 F e C l 3 - . 4 2 2 i i i ) H y d r a t e d L i m e L i m e S l u d g e ( m g / L ) = 1 . 0 4 A l k + 5 . 6 P + 2 . 4 C O I n c o m p u t i n g t h e l i m e r e q u i r e m e n t s a n d l i m e s l u d g e p r o d u c t i o n , t h e k n o w l e d g e o f t h e a l k a l i n i t y o f t h e s t r e a m b e i n g t r e a t e d i s v e r y i m p o r t a n t . I n t h e C a l g a r y , E d m o n t o n a n d - 98 -S a s k a t o o n p l a n t s , i t w a s p r o p o s e d t o a d d l i m e t o s u p e r n a t a n t r e c y c l e d f r o m s l u d g e d e w a t e r i n g l a g o o n s . O f t h e s e t h r e e p l a n t s , o n l y S a s k a t o o n m o n i t o r s t h e a l k a l i n i t y o f t h e l a g o o n s u p e r n a t a n t . T h e r e f o r e , b e c a u s e C a l g a r y , E d m o n t o n a n d S a s k a t o o n a l l u t i l i z e t h e s a m e s l u d g e h a n d l i n g p r o c e s s ( a n a e r o b i c d i g e s t i o n f o l l o w e d b y d e w a t e r i n g l a g o o n s ) , t h e a l k a l i n i t i e s o f t h e l a g o o n s u p e r n a t a n t f o r C a l g a r y a n d E d m o n t o n w e r e a s s u m e d t o b e e q u i v a l e n t t o t h a t o f S a s k a t o o n . T h i s i s n o t e d b e c a u s e t h e s u p e r n a t a n t a l k a l i n i t i e s r e p o r t e d b y S a s k a t o o n ( 3 0 0 t o 4 0 0 m g / L C a C 0 3 ) a r e c o n s i d e r a b l y l e s s t h a n t h o s e m e a s u r e d i n t h e a n a e r o b i c d i g e s t o r ( 2 0 0 0 m g / L C a C 0 3 ) . I t w o u l d a p p e a r t h a t t h e a l k a l i n i t y i s b e i n g n e u t r a l i z e d b y r a i n f a l l a n d / o r s u r f a c e r u n - o f f . S i g n i f i c a n t i m p a c t s o n l i m e r e q u i r e m e n t s a n d s l u d g e p r o d u c t i o n w o u l d b e r e a l i z e d i f t h i s i s n o t t h e c a s e f o r C a l g a r y a n d E d m o n t o n . 3 . 3 . 1 1 O p e r a t i o n s R e q u i r e m e n t s T h e o p e r a t i o n o f a B i o - P r e m o v a l p l a n t r e q u i r e s a s o m e w h a t d i f f e r e n t p h i l o s o p h y t h a n t h e o p e r a t i o n o f a c h e m i c a l p h o s p h o r u s r e m o v a l p l a n t . S t e v e n s ( 1 9 8 8 ) n o t e s t h a t o p e r a t o r s m u s t p a y m o r e a t t e n t i o n t o t h e l a b a n a l y s i s r e s u l t s i n a B i o - P p l a n t t h a n i n a c o n v e n t i o n a l c h e m i c a l r e m o v a l p l a n t . - 99 -T r a d i t i o n a l o p e r a t i n g parameters such as flow r a t e s and sludge b l a n k e t depth should be augmented by chemical a n a l y s i s data (e.g. anaerobic zone n i t r a t e c o n c e n t r a t i o n , fermenter VFA c o n c e n t r a t i o n s , ORP readouts, e t c ) . As a r e s u l t , o p e r a t o r s r e q u i r e a b e t t e r understanding of the process b i o c h e m i s t r y than they do f o r a c o n v e n t i o n a l p l a n t . Depending upon the type and s i z e of the p l a n t , a Bio-P removal o p e r a t i o n may r e q u i r e a d d i t i o n a l o p e r a t i o n s and maintenance s t a f f compared to a chemical phosphorus removal o p e r a t i o n . C e r t a i n l y , a Bio-P removal o p e r a t i o n r e q u i r e s more l a b o r a t o r y a n a l y s i s . As a minimum, i t i s f e l t t h a t d a i l y a n a l y s e s of the f o l l o w i n g i s r e q u i r e d over and above t h a t r e q u i r e d f o r a chemical phosphorus removal o p e r a t i o n : i ) Fermenter l i q u o r VFA's, BOD, TSS, VSS. i i ) Fermenter supernatant VFA's, BOD, TSS, VSS ( i f a g r a v i t y t h i c k e n e r i s used f o r a fermenter). i i i ) B i o r e a c t o r Anaerobic Zone N0 3. Since BOD, TSS and VSS analyses are r o u t i n e l y done on a d a i l y b a s i s i n most p l a n t s , the a d d i t i o n a l analyses f o r these parameters r e q u i r e d f o r a Bio-P o p e r a t i o n would consume v e r y l i t t l e a d d i t i o n a l time. In p l a n t s o p e r a t i n g anaerobic - 1 0 0 -d i g e s t o r s , l i t t l e a d d i t i o n a l t i m e w o u l d b e r e q u i r e d t o c a r r y o u t t h e B i o - P r e l a t e d V F A a n a l y s e s , s i n c e V F A m o n i t o r i n g i s a p a r t o f n o r m a l d i g e s t o r o p e r a t i o n . I n p l a n t s n o t o p e r a t i n g d i g e s t o r s a p p r o x i m a t e l y o n e a d d i t i o n a l h o u r o f l a b o r a t o r y t i m e p e r d a y w o u l d b e r e q u i r e d t o p e r f o r m t h e V F A a n a l y s e s . A d i s t i l l a t i o n m e t h o d w o u l d b e u s e d f o r t h i s a n a l y s i s . I n p l a n t s h a v i n g a m m o n i a r e m o v a l s t a n d a r d s , n i t r a t e a n a l y s e s a r e g e n e r a l l y c a r r i e d o u t a n d h e n c e , v e r y l i t t l e a d d i t i o n a l t i m e w o u l d b e r e q u i r e d f o r t h e B i o - P r e l a t e d n i t r a t e a n a l y s e s . I n p l a n t s n o t h a v i n g a m m o n i a s t a n d a r d s , n i t r a t e a n a l y s e s m a y o r m a y n o t b e p e r f o r m e d . I f n o t , a p p r o x i m a t e l y o n e a d d i t i o n a l h o u r p e r d a y o f l a b o r a t o r y t i m e w o u l d b e r e q u i r e d f o r t h i s a n a l y s i s . A c o l o u r m e t r i c t e c h n i q u e w o u l d l i k e l y b e u s e d . I n p l a n t s n o t u s i n g a u t o m a t e d DO c o n t r o l p r e s e n t l y , t h e r e q u i r e m e n t f o r a u t o m a t e d DO c o n t r o l a s s o c i a t e d w i t h B i o - P r e m o v a l , w i l l r e s u l t i n a d d i t i o n a l m a i n t e n a n c e t i m e . S t e v e n s ( 1 9 8 8 ) e s t i m a t e s t h a t a p p r o x i m a t e l y o n e m a n h o u r p e r d a y i s d e v o t e d t o m a i n t a i n i n g t h e DO c o n t r o l s y s t e m a t K e l o w n a . T h e m a j o r i t y o f t h i s t i m e i s s p e n t c l e a n i n g t h e DO p r o b e s . T h e i n s t a l l a t i o n o f a d d i t i o n a l u n i t o p e r a t i o n s ( e . g . p r i m a r y s l u d g e f e r m e n t a t i o n , l i m e t r e a t m e n t f a c i l i t i e s , d i s s o l v e d a i r f l o t a t i o n ) f o r a B i o - P r e m o v a l o p e r a t i o n w i l l a l s o - 1 0 1 -r e s u l t i n a d d i t i o n a l o p e r a t i o n a n d m a i n t e n a n c e t i m e . T h e e x a c t a m o u n t w i l l b e d e p e n d e n t u p o n t h e n u m b e r , t y p e a n d s i z e o f t h e u n i t o p e r a t i o n s a d d e d , a n d t h e d e g r e e o f a u t o m a t i o n i n t h e p l a n t . I n q u a n t i f y i n g t h e r e q u i r e m e n t f o r a d d i t i o n a l o p e r a t i o n s a n d m a i n t e n a n c e s t a f f f o r e a c h p l a n t , c o n s i d e r a t i o n w a s t h e r e f o r e g i v e n t o t h e t y p e a n d s i z e o f t h e u n i t o p e r a t i o n s a d d e d , a n d t h e a d d i t i o n a l a m o u n t o f l a b a n a l y s i s r e q u i r e d . A d d i t i o n a l s t a f f i n g r e q u i r e m e n t s w e r e e x p r e s s e d i n w h o l e n u m b e r s ( i . e . i t w a s a s s u m e d t h a t a f u l l - t i m e p e r s o n w o u l d b e h i r e d e v e n i f t h e r e w a s o n l y a p a r t - t i m e r e q u i r e m e n t ) . 3 . 3 . 1 2 M i s c e l l a n e o u s M i s c e l l a n e o u s p a r a m e t e r s u s e d i n t h e r e t r o f i t d e s i g n s w e r e a s f o l l o w s : i ) P i p e S i z i n g a l l p i p e s s i z e d w e r e b a s e d o n a v e l o c i t y o f 1 . 5 m / s a t a v e r a g e f l o w c o n d i t i o n s t h e m i n i m u m p i p e d i a m e t e r u s e d f o r s l u d g e l i n e s w a s 150mm t h e m i n i m u m p i p e d i a m e t e r u s e d f o r a l l o t h e r s e r v i c e s w a s 100mm - f r i c t i o n f a c t o r s f o r s l u d g e p i p i n g w e r e c a l c u l a t e d a s 3 t i m e s t h e f a c t o r f o r w a t e r f i l l e d p i p i n g - 1 0 2 -i i ) C o n t r o l V a l v e s c o n t r o l v a l v e s w e r e a s s u m e d t o b e o n e p i p e d i a m e t e r s m a l l e r t h a n t h e p i p e i n w h i c h t h e y w e r e i n s t a l l e d a p r e s s u r e d r o p o f 1 4 0 k P a w a s a s s u m e d a c r o s s a l l c o n t r o l v a l v e s t o b e b u r i e d a m i n i m u m o f 2 . 0m b e l o w g r a d e f o r O n t a r i o p l a n t s a n d 2 . 6 m f o r A l b e r t a a n d S a s k a t c h e w a n p l a n t s t o m i n i m i z e f r e e z e / t h a w e f f e c t s i i i ) U n d e r g r o u n d P i p i n g 3 . 4 C o s t E s t i m a t i n g B a s i s G i v e n t h e l e v e l o f d e t a i l o f t h e e n g i n e e r i n g a s s o c i a t e d w i t h t h e r e t r o f i t d e s i g n s , i t w a s f e l t t h a t e s t i m a t e s h a v i n g ± 2 5 % a c c u r a c y w e r e a c h i e v a b l e . T h e r e f o r e , e s t i m a t i n g t e c h n i q u e s c o m p a t i b l e w i t h t h i s l e v e l o f a c c u r a c y w e r e s e l e c t e d . 3 . 4 . 1 C a p i t a l C o s t s I n c r e m e n t a l c a p i t a l c o s t s w e r e e s t i m a t e d u s i n g t h e f o l l o w i n g t w o m e t h o d s : 1 . P r e p a r i n g a n d p r i c i n g m a t e r i a l t a k e - o f f s ( M T O ' s ) . 2 . F a c t o r i n g . - 1 0 3 -I n g e n e r a l , M T O ' s w e r e p r e p a r e d f o r m e c h n i c a l e q u i p m e n t , l o n g p i p i n g r u n s , m a j o r e x c a v a t i o n s , c o n c r e t e t u n n e l s a n d t a n k s , b u i l d i n g s a n d m a j o r i n s t r u m e n t a t i o n a n d p r o c e s s c o n t r o l e q u i p m e n t . T a b l e 3 . 2 l i s t s , i n d e t a i l , t h e i t e m s f o r w h i c h M T O ' s w e r e p r e p a r e d , a n d i d e n t i f i e s t h e l e v e l o f d e t a i l a s s o c i a t e d w i t h t h e M T O s p e c i f i c a t i o n f o r e a c h i t e m . I n m o s t c a s e s , t h e t o t a l i n s t a l l e d c o s t ( T I C ) f o r t h e s e M T O i t e m s w a s e s t i m a t e d a s t h e s u m o f t h e m a t e r i a l c o s t s o f t h e i t e m , t h e l a b o u r c o s t s f o r i n s t a l l a t i o n , f r e i g h t c h a r g e s , a n d f e d e r a l a n d p r o v i n c i a l s a l e s t a x . E x p r e s s e d a l g e b r a i c a l l y , t h e T I C f o r a n y i t e m c a n b e e x p r e s s e d a s f o l l o w s : T I C = M C + MHS X L R + F + F S T + P S T W h e r e T I C = t o t a l i n s t a l l e d c o s t o f t h e i t e m M C = m a t e r i a l c o s t MHS = i n s t a l l a t i o n m a n h o u r s L R = l a b o u r r a t e ( $ / m h ) F = f r e i g h t c h a r g e s F S T = f e d e r a l s a l e s t a x P S T = p r o v i n c i a l s a l e s t a x M a t e r i a l c o s t s a n d i n s t a l l a t i o n m a n h o u r s w e r e o b t a i n e d f r o m s u p p l i e r s , p r o f e s s i o n a l c o s t e s t i m a t o r s , p u b l i s h e d e s t i m a t i n g h a n d b o o k s a n d u n p u b l i s h e d h i s t o r i c a l d a t a . A l i s t i n g o f m a t e r i a l c o s t s a n d a s s o c i a t e d i n s t a l l a t i o n m a n h o u r s f o r a l l i t e m s s p e c i f i e d i n t h i s t h e s i s i s p r e s e n t e d i n A p p e n d i x C . S o u r c e s o f t h e s e c o s t s a r e a l s o p r e s e n t e d i n A p p e n d i x C . G E N E R A L C O M M O D I T Y C L A S S 1 . M e c h a n i c a l E q u i p m e n t 2 . P i p i n g 3 . C i v i l C O M M O D I T Y i ) P u m p s i i ) M i x e r s i i i ) C h e m i c a l F e e d e r s i v ) S l u d g e C o l l e c t o r s v ) S t e e l S t o r a g e T a n k s v i ) C h e m i c a l S t o r a g e ' S i l o s v i i ) A e r a t o r s i ) P i p e i ) E x c a v a t i o n s i i ) R e i n f o r c e d C o n c r e t e i i i ) B u i l d i n g s T A B L E 3 . 2 - M A T E R I A L T A K E - ' L E V E L O F D E T A I L A S S O C I A T E D W I T H M T O S P E C I F I C A T I O N - Q , T D H , D r i v e r k W , G e n e r a l T y p e ( e . g . c e n t r i f u g a l , P D , e t c . ) - D r i v e r kW - C h e m i c a l T h r o u g h p u t , G e n e r a l t y p e ( e . g . s c r e w t y p e ) - T h i c k e n e r / C l a r i f i e r D i a m e t e r , SWD D i m e n s i o n s , v o l u m e V o l u m e , L i n e d / u n l i n e d T y p e , D r i v e kW P i p e d i a m e t e r , l e n g t h a n d m a t e r i a l s p e c i f i c a t i o n E x c a v a t i o n a n d b a c k f i l l q u a n t i t i e s f o r m a j o r e x c a v a t i o n s ( u n d e r g r o u n d t a n k s , t u n n e l s a n d p i p i n g ) C o n c r e t e v o l u m e s f o r t u n n e l s a n d t a n k s F l o o r a r e a S P E C I F I C A T I O N S GENERAL COMMODITY CLASS COMMODITY LEVEL OF DETAIL ASSOCIATED WITH MTO SPECIFICATION Instrumentation and C o n t r o l i ) C o n t r o l Valves i i ) Flow Recorders i i i ) Flow Meters i v ) Flow T r a n s m i t t e r s v) M i c r o p r o c e s s o r Based C o n t r o l l e r s v i ) ORP Probes v i i ) DO Probes V a l v e type (e.g. b u t t e r f l y ) , s i z e and and a c t u a t o r d e t a i l s t h r o t t l i n g a c t u a t o r versus o n - o f f ) Panel vs l o c a l mount Meter type (e.g. o r i f i c e ) & s i z e E l e c t r o n i c vs pneumatic Number of loops c o n t r o l l e d None None T A B L E 3 . 2 - M A T E R I A L T A K E - O F F S P E C I F I C A T I O N S ( c o n t 1 d ) - 1 0 6 -M a t e r i a l c o s t s a n d i n s t a l l a t i o n m a n h o u r r a t e s w e r e c o n s i d e r e d t o b e t h e s a m e f o r a l l m u n i c i p a l i t i e s . R . S . M e a n s I n c . ( 1 9 8 7 ) s h o w s t h a t t h e m a x i m u m d i f f e r e n c e i n t h e o v e r a l l c o n s t r u c t i o n c o m p o s i t e i n d e x b e t w e e n t w o l o c a t i o n s i n C a n a d a i s a p p r o x i m a t e l y 4%. G i v e n t h e a c c u r a c y o f t h e e s t i m a t e , i t w a s f e l t t h a t t h i s w a s i n s i g n i f i c a n t . A c o m p o s i t e l a b o u r r a t e o f $ 3 1 . 0 0 / h o u r w a s s e l e c t e d . T h e b r e a k d o w n o f t h i s r a t e i s a s f o l l o w s : B a s e S a l a r y - $ 1 8 . 0 0 S a l a r y B u r d e n - $ 6 . 0 0 S u p e r v i s i o n - $ 2 . 0 0 C o n s u m a b l e s - $ 1 . 0 0 O v e r h e a d a n d P r o f i t - $ 4 . 0 0 T O T A L $ 3 1 . 0 0 / h r I n s e l e c t i n g t h i s r a t e , t h e f o l l o w i n g a s s u m p t i o n s w e r e m a d e : B a s e D a t e - A p r i l , 1 9 8 8 C u r r e n c y - C a n a d i a n d o l l a r s L a b o u r C r a f t s - U n i o n W o r k W e e k - 4 0 h o u r s - n o o v e r t i m e V a r i a n c e w i t h L o c a t i o n - N o n e - 1 0 7 -F r e i g h t c h a r g e s w e r e e s t i m a t e d a s a p e r c e n t a g e o f t h e m a t e r i a l c o s t . A n a v e r a g e r a t e o f 4% o f m a t e r i a l c o s t s w a s a s s u m e d f o r A l b e r t a a n d S a s k a t c h e w a n p l a n t s , w h i l e a n a v e r a g e o f 2% w a s a s s u m e d f o r O n t a r i o p l a n t s . F e d e r a l s a l e s t a x i s n o r m a l l y 8% o f t h e m a t e r i a l c o s t f o r p i p e , f i t t i n g s a n d c o n c r e t e , a n d 12% f o r a l l o t h e r i t e m s i n a c c o r d a n c e w i t h t h e E x c i s e T a x A c t . H o w e v e r , e q u i p m e n t f o r m u n i c i p a l s e w a g e t r e a t m e n t i s e x e m p t f r o m f e d e r a l t a x u n d e r P a r t 12 o f S c h e d u l e 13 o f t h e A c t . T h e r e f o r e , n o f e d e r a l t a x w a s i n c l u d e d i n t h e e s t i m a t e s . A p r o v i n c i a l s a l e s t a x o f 7% w a s a p p l i e d t o t h e m a t e r i a l c o s t s f o r t h e p l a n t s i n S a s k a t c h e w a n ( S t e s s a n , 1 9 8 8 ) . N o p r o v i n c i a l s a l e s t a x e x i s t s i n A l b e r t a . M u n i c i p a l s e w a g e t r e a t m e n t e q u i p m e n t i s e x e m p t f r o m t h e 8% p r o v i n c i a l s a l e s t a x i n O n t a r i o ( O n t a r i o M i n i s t r y o f R e v e n u e , 1 9 8 8 ) . T h e r e f o r e , n o p r o v i n c i a l t a x e s w e r e a p p l i e d t o O n t a r i o a n d A l b e r t a p l a n t s . T h e s e c o n d m e t h o d o f e s t i m a t i n g t h e i n c r e m e n t a l c a p i t a l c o s t s w a s f a c t o r i n g . T h i s w a s u s e d t o e s t i m a t e t h e c o s t o f c i v i l , p i p i n g , e l e c t r i c a l , i n s t r u m e n t a n d p a i n t i n g b u l k m a t e r i a l s i n a r e a s w h e r e i t w a s f e l t t h a t t h e p r e p a r a t i o n o f M T O ' s w a s t o o c u m b e r s o m e . I n g e n e r a l , f a c t o r i n g w a s l i m i t e d t o b u l k m a t e r i a l s i n t h e v i c i n i t y o f m e c h a n i c a l e q u i p m e n t . T a b l e 3 . 3 s u m m a r i z e s t h e e x t e n t o f b u l k m a t e r i a l c o s t f a c t o r i n g w i t h i n t h i s t h e s i s . - 108 -F a c t o r i n g i n v o l v e s e s t i m a t i n g t h e T I C o f b u l k s a s s o c i a t e d w i t h a p i e c e o f e q u i p m e n t w i t h i n a c e r t a i n r a d i u s o f t h e e q u i p m e n t , a s a p e r c e n t a g e o f t h e m a t e r i a l c o s t o f t h e e q u i p m e n t . T h e r e f o r e , t h e T I C o f t h e e q u i p m e n t a n d i t s b u l k s w i t h i n a c e r t a i n r a d i u s o f t h e e q u i p m e n t , c a n b e e x p r e s s e d b y t h e f o l l o w i n g e q u a t i o n : A l i s t i n g o f t h e f a c t o r s u s e d i n d e v e l o p i n g t h e r e t r o f i t c o s t e s t i m a t e s i s p r e s e n t e d i n A p p e n d i x C . F a c t o r s w e r e o b t a i n e d f r o m s u p p l i e r s , p r o f e s s i o n a l c o s t e s t i m a t o r s a n d u n p u b l i s h e d h i s t o r i c a l d a t a . S p e c i f i c s o u r c e s f o r a l l f a c t o r s u s e d i s a l s o p r o v i d e d i n A p p e n d i x C . I t s h o u l d b e n o t e d t h a t t h e T I C ' s a s c a l c u l a t e d b y t h e a b o v e t w o m e t h o d s d o n o t i n c l u d e a l l o w a n c e s f o r e n g i n e e r i n g . T h e r e f o r e , t h e t o t a l i n c r e m e n t a l c o s t o f t h e p l a n t r e t r o f i t c a n b e c a l c u l a t e d b y t h e f o l l o w i n g e q u a t i o n : T C = Z T I ^ + E N G W h e r e T C = t o t a l i n c r e m e n t a l c o s t a s s o c i a t e d w i t h t h e p l a n t r e t r o f i t T I C . = t o t a l i n s t a l l e d c o s t f o r t h e i t h i t e m 1 a s s o c i a t e d w i t h t h e p l a n t r e t r o f i t E N G = c o s t o f e n g i n e e r i n g t h e r e t r o f i t T I C = M C X B F + F + F S T + P S T W h e r e T I C M C B F F , F S T , P S T t o t a l i n s t a l l e d c o s t o f t h e e q u i p m e n t a n d i t s b u l k s m a t e r i a l c o s t o f t h e e q u i p m e n t b u l k f a c t o r f r e i g h t , f e d e r a l s a l e s t a x a n d p r o v i n c i a l s a l e s t a x , r e s p e c t i v e l y C O M M O D I T Y M e c h a n i c a l E q u i p m e n t -P i p i n g C i v i l E l e c t r i c a l I n s t r u m e n t a t i o n EXTENT OF FACTORING I n s t a l l a t i o n c o s t f a c t o r e d f r o m e q u i p m e n t c a p i t a l c o s t M a t e r i a l a n d i n s t a l l a t i o n c o s t o f a l l p i p e , v a l v e s a n d f i t t i n g s w i t h i n a 5 0 m e t e r r a d i u s o f i t s a s s o c i a t e d p i e c e o f m e c h a n i c a l e q u i p m e n t f a c t o r e d f r o m e q u i p m e n t c a p i t a l c o s t M a t e r i a l a n d i n s t a l l a t i o n c o s t o f a l l e q u i p m e n t f o u n d a t i o n s f a c t o r e d f r o m e q u i p m e n t c a p i t a l c o s t . T h i s i n c l u d e s e x c a v a t i o n , b a c k f i l l , c o n c r e t e , r e i n f o r c i n g s t e e l , f o r m w o r k , e m b e d d e d s t e e l a n d g r o u t . M a t e r i a l a n d i n s t a l l a t i o n c o s t o f h a r d w i r i n g a l l m e c h a n i c a l e q u i p m e n t t o a m o t o r c o n t r o l c e n t e r ( M C C ) f a c t o r e d f r o m e q u i p m e n t c a p i t a l c o s t . I n a l l c a s e s i t w a s a s s u m e d t h a t t h e M C C w a s w i t h i n 2 0 0 m e t e r s o f t h e e q u i p m e n t . M a t e r i a l a n d i n s t a l l a t i o n c o s t o f a r e a l i g h t i n g f o r m e c h a n i c a l e q u i p m e n t f a c t o r e d f r o m e q u i p m e n t c a p i t a l c o s t . M a t e r i a l a n d i n s t a l l a t i o n c o s t o f h a r d w i r i n g a l l f i e l d m o u n t e d i n s t r u m e n t s t o a p r o c e s s c o n t r o l l e r o r d i s p l a y p a n e l f a c t o r e d f r o m e q u i p m e n t c a p i t a l c o s t . I n a l l c a s e s , i t w a s a s s u m e d t h a t t h e c o n t r o l l e r / p a n e l w a s w i t h i n 2 0 0 m e t e r s o f t h e e q u i p m e n t . . 3 - E X T E N T O F C A P I T A L C O S T F A C T O R I N G EXTENT OF FACTORING M a t e r i a l and labour c o s t o f p a i n t i n g a l l equipment and a s s o c i a t e d p i p i n g w i t h i n a 50 meter r a d i u s o f the equipment f a c t o r e d from equipment c a p i t a l c o s t . T A B L E 3.3 - E X T E N T O F C A P I T A L C O S T F A C T O R I N G (cont'd) - I l l -E n g i n e e r i n g w a s a s s u m e d t o b e e q u a l t o 12% o f t h e t o t a l i n s t a l l e d c o s t ( i . e . 2, T I C ^ ) . T h i s f i g u r e w a s b a s e d o n t h e a u t h o r ' s p e r s o n a l e x p e r i e n c e a n d d i s c u s s i o n s w i t h p r o f e s s i o n a l c o s t e s t i m a t o r s ( D i c a i r e , 1 9 8 8 ) . T h e v a l i d i t y o f t h e s e m e t h o d s t o g e n e r a t e e s t i m a t e s h a v i n g ± 25% a c c u r a c y i s v e r y s u b j e c t i v e . H o w e v e r , b a s e d o n t h e a u t h o r ' s p e r s o n a l e x p e r i e n c e a n d d i s c u s s i o n s w i t h e s t i m a t o r s ( D i c a i r e , 1 9 8 8 ) i t w a s f e l t t h a t t h i s a c c u r a c y w a s e a s i l y a c h i e v a b l e . 3 . 4 . 2 O p e r a t i n g C o s t s I n c r e m e n t a l o p e r a t i n g c o s t s w h i c h r e q u i r e d e s t i m a t i n g i n c l u d e d c h e m i c a l c o s t s ( a l u m , f e r r i c c h l o r i d e a n d h y d r a t e d l i m e ) , p o w e r , o p e r a t i o n s , l a b o u r , n a t u r a l g a s , l a b o r a t o r y a n a l y s i s a n d m a i n t e n a n c e m a t e r i a l s . C h e m i c a l c o s t s w e r e o b t a i n e d f r o m t h e p l a n t s d i r e c t l y a n d w e r e c o n f i r m e d w i t h q u o t e s f r o m s u p p l i e r s . T a b l e 3 . 4 p r o v i d e s a s u m m a r y o f c h e m i c a l c o s t s u s e d i n t h e e s t i m a t i n g . I t s h o u l d b e n o t e d t h a t a l u m c o s t s a r e l i s t e d o n a d r y w e i g h t b a s i s . I n m o s t c a s e s l i q u i d a l u m c o n t a i n i n g 4 8 . 8 % a l u m b y w e i g h t i s a c t u a l l y u s e d . T h e r e f o r e , t h e p r i c e s i n t h e t a b l e s h o u l d b e m u l t i p l i e d b y 0 . 4 8 8 t o o b t a i n t h e u n i t c o s t o f t h e l i q u i d . - 112 -Power c o s t s were ob t a i n e d from S t a t i s t i c s Canada (1988) and are l i s t e d below. Costs are based on the t o t a l monthly b i l l o f an i n d u s t r i a l consumer d i v i d e d by t h e average power drawn. T h e r e f o r e , the c o s t s i n c l u d e an allowance f o r demand although t h i s may not a c c u r a t e l y r e f l e c t t he p l a n t s ' w i t h the l o c a l u t i l i t y . P l a n t Power Cost ($/kw-hr) 1. C a l g a r y 0.016 2. Edmonton 0.016 3. Regina 0.021 4. Saskatoon 0.021 5. Windsor 0.016 6. M i l t o n 0.017 7. Grimsby 0.015 8. E l m i r a 0.018 9. W e l l e s l e y 0.018 Labour c o s t s were based on s a l a r i e d "water systems" s t a f f r a t e s as per S t a t i s t i c s Canada (1988A). S a l a r y burden was est i m a t e d as 30% of the S t a t i s t i c s Canada r a t e s . Costs ( i n c l u d i n g burden) are l i s t e d below: 1. A l b e r t a $905/week 2. Saskatchewan $763/week 3. O n t a r i o $802/week N a t u r a l gas c o s t s were assumed t o be $2.30/MMBTU (Husky O i l , 1986). CHEMICAL COST ($/dry tonne) PLANT CHEMICALS REQUIRED PLANT PRICE (1987 $) SUPPLIER* * QUOTE (1988 $) PRICE USED (1988 $) 1. Edmonton Alum N/A 215 215 Ca(OH) 2 N/A 107 107 2. C a l g a r y Alum 220 215 215 Ca(OH) 2 N/A 97 97 3 . Regina Alum 192 215 215 Ca(OH) 2 N/A 120 120 4. Saskatoon Alum 213 215 215 Ca(OH), N/A 117 117 5. Windsor A l C l g (spent c a t a l y s t ) 23 N/A 2 4 ( 2 ) 6. M i l t o n Alum 167 186 186 Lime N/A 85 85 7. Grimsby F e C l 2 3 0 0 ( 3 ) 4 9 5 ( 3 ) 3 0 0 ( 3 ) Lime N/A 85 85 8. E l m i r a F e C l 3 682<3> 1 0 4 5 ( 3 ) 682<3> 9. W e l l e s l e y Alum 241 186 241 T A B L E 3 . 4 - C H E M I C A L C O S T S U M M A R Y N o t e s : (1) FOB P l a n t S i t e (2) 5% I n f l a t i o n f o r 1987 assumed (3) Based on one tonne of Fe - 1 1 4 -L a b o r a t o r y a n a l y s i s c o s t s w e r e b a s e d o n t h e a b o v e l a b o u r r a t e s . N o a l l o w a n c e f o r l a b s u p p l i e s w a s i n c l u d e d . M a i n t e n a n c e m a t e r i a l s a r e i t e m s w h i c h a r e c o n s u m e d i n t h e r o u t i n e m a i n t e n a n c e o f t h e p l a n t . T h e s e i n c l u d e l u b r i c a t i n g f l u i d s , g a s k e t s , s p a r e f i t t i n g s , e t c . T h e s e w e r e e s t i m a t e d a s 1% p e r y e a r o f t h e t o t a l i n c r e m e n t a l m a t e r i a l c o s t a s s o c i a t e d w i t h t h e B i o - P r e t r o f i t . 3 . 5 E c o n o m i c A n a l y s i s B a s i s I n a n a l y z i n g t h e i n c r e m e n t a l c a p i t a l e x p e n d i t u r e s a n d o p e r a t i n g c o s t s a v i n g s a s s o c i a t e d w i t h B i o - P r e m o v a l , b o t h t h e s i m p l e p a y b a c k p e r i o d a n d i n t e r n a l r a t e o f r e t u r n w e r e c a l c u l a t e d f o r e a c h p l a n t . T h e s i m p l e p a y b a c k p e r i o d r e p r e s e n t s t h e p e r i o d o f t i m e w h i c h w o u l d b e r e q u i r e d t o p a y o u t t h e c a p i t a l i n v e s t m e n t f r o m t h e r e s u l t i n g s a v i n g s i n o p e r a t i o n a l c o s t s . E x p r e s s e d a l g e b r a i c a l l y , t h e s i m p l e p a y b a c k p e r i o d i s a s f o l l o w s : S P P = A C C A O C W h e r e S P P A C C A O C = s i m p l e p a y b a c k p e r i o d ( y e a r s ) = i n c r e m e n t a l c a p i t a l c o s t ( $ ) = a n n u a l r e d u c t i o n i n o p e r a t i n g c o s t s a s a r e s u l t o f t h e i n v e s t m e n t ( $ / y e a r ) - 1 1 5 -S i m p l e p a y b a c k p e r i o d s w e r e c o m p u t e d s i n c e t h e y a r e c o m m o n l y u s e d a s a p a r a m e t e r f o r e c o n o m i c d e c i s i o n m a k i n g . H o w e v e r , t h e y h a v e a w e a k n e s s i n t h a t t h e y d o n o t m a k e a n y a l l o w a n c e f o r t h e t i m e v a l u e o f m o n e y . T h e r e f o r e , I R R ' s w e r e a l s o c a l c u l a t e d f o r e a c h p l a n t . I R R r e p r e s e n t s t h e r a t e o f r e t u r n o n a n i n v e s t m e n t s u c h t h a t t h e n e t p r e s e n t v a l u e o f t h e i n v e s t i m e n t i s z e r o . A s s u m i n g c o n t i n u o u s c o m p o u n d i n g o f i n t e r e s t , c a p i t a l e x p e n d i t u r e s c o n c e n t r a t e d a t t i m e z e r o , n o i n f l a t i o n , a n d n o s a l v a g e v a l u e o f t h e p u r c h a s e d e q u i p m e n t a n d m a t e r i a l s a t t h e e n d o f t h e p r o j e c t , t h e I R R c a n b e c a l c u l a t e d a s f o l l o w s ( a d a p t e d f r o m L i n z e y e t a l . , 1 9 7 3 ) : zl ( e " r t - 1) = A C C r A O C W h e r e t = p r o j e c t l i f e r = I R R I R R ' s w e r e c a l c u l a t e d f o r p r o j e c t l i v e s o f 5 , 1 0 , 1 5 a n d 2 0 y e a r s . T w e n t y y e a r s w a s c o n s i d e r e d t o b e t h e m a x i m u m l i f e o f a s e w a g e t r e a t m e n t p l a n t p r i o r t o e x p a n s i o n o r u p g r a d i n g . I R R ' s f o r s h o r t e r p r o j e c t l i v e s w e r e c a l c u l a t e d t o a s s e s s t h e e c o n o m i c s o f B i o - P r e m o v a l f o r e x i s t i n g p l a n t s w h e r e e x p a n s i o n s o r u p g r a d i n g c o u l d o c c u r i n l e s s t h a n 2 0 y e a r s . - 1 1 6 -I t s h o u l d b e r e - e m p h a s i z e d t h a t I R R ' s w e r e c a l c u l a t e d a s s u m i n g n o i n f l a t i o n . T h e c a l c u l a t i o n o f I R R i n c l u d i n g c o n s t a n t i n f l a t i o n i s a c h i e v e d b y m e r e l y a d d i n g t h e a s s u m e d i n f l a t i o n r a t e t o t h e I R R . F o r e x a m p l e , i f t h e I R R i s 5% a n d t h e a n t i c i p a t e d i n f l a t i o n r a t e i s 10%, t h e I R R i n c l u d i n g i n f l a t i o n i s 15%. - 1 1 7 -4 . 0 R E S U L T S W i t h i n t h i s s e c t i o n , r e s u l t s w i l l b e d i s c u s s e d f o r e a c h p l a n t o n a n i n d i v i d u a l b a s i s . T h e e x i s t i n g o p e r a t i o n o f e a c h p l a n t i s i n i t i a l l y d i s c u s s e d w i t h r e s p e c t t o p r o c e s s d e s c r i p t i o n , i n f l u e n t c h a r a c t e r i s t i c s , e f f l u e n t s t a n d a r d s , p l a n t p e r f o r m a n c e a n d s l u d g e d i s p o s a l . T h e m o d i f i c a t i o n s r e q u i r e d f o r r e t r o f i t t i n g f o r B i o - P r e m o v a l a r e t h e n p r e s e n t e d a n d c o m p a r e d t o t h o s e r e q u i r e d ( o r a l r e a d y p r e s e n t ) f o r c h e m i c a l p h o s p h o r u s r e m o v a l . I n c r e m e n t a l e q u i p m e n t a n d b u l k m a t e r i a l l i s t s a r e d e v e l o p e d a n d p r e s e n t e d s u c h t h a t t h e i n c r e m e n t a l c a p i t a l c o s t f o r B i o - P r e m o v a l c a n b e c a l c u l a t e d . I n c r e m e n t a l o p e r a t i o n a l r e q u i r e m e n t s a r e t h e n i d e n t i f i e d s u c h t h a t t h e s a v i n g s i n o p e r a t i n g c o s t s a s s o c i a t e d w i t h B i o - P r e m o v a l c a n b e c a l c u l a t e d . F i n a l l y , i n c r e m e n t a l c a p i t a l a n d o p e r a t i n g c o s t s a s s o c i a t e d w i t h B i o - P r e m o v a l a r e p r e s e n t e d a n d i n t e r n a l r a t e s o f r e t u r n ( I R R ' s ) a r e c a l c u l a t e d f o r v a r i o u s p r o j e c t l i v e s . 4 . 1 C a l g a r y B o n n y b r o o k W a s t e w a t e r T r e a t m e n t P l a n t 4 . 1 . 1 P l a n t D e s c r i p t i o n T h e B o n n y b r o o k W a s t e w a t e r T r e a t m e n t p l a n t i s t h e l a r g e r o f t w o s e w a g e t r e a t m e n t p l a n s w h i c h s e r v i c e t h e C i t y o f C a l g a r y . L o c a t e d i n s o u t h C a l g a r y o n t h e B o w R i v e r , t h e p l a n t c u r r e n t l y - 118 -serves a p o p u l a t i o n of 506,000. Inflow to the p l a n t averaged 3 344,000 m /d i n 1986. The d e s i g n c a p a c i t y o f the p l a n t i s 3 450,000 m /d based on average d a i l y flow. The p l a n t uses the a c t i v a t e d sludge p r o c e s s and c o n t a i n s s c r e e n i n g , aerated g r i t removal, primary sedimentation, g r a v i t y t h i c k e n i n g , d i f f u s e d a i r and mechanical a e r a t i o n , d i s s o l v e d a i r f l o t a t i o n , secondary sedimentation, s i n g l e stage anaerobic d i g e s t i o n , sludge lagoons and chemical phosphorus removal u n i t o p e r a t i o n s . Flowsheets and l a y o u t drawings are prese n t e d i n F i g u r e s 4.1 and 4.2, r e s p e c t i v e l y . As shown i n the drawings, primary s e d i m e n t a t i o n i s c a r r i e d out i n twelve primary c l a r i f i e r s . Primary e f f l u e n t i s routed to two s e t s o f b i o r e a c t o r s . Reactors 1 t o 4 ( i n s t a l l e d i n 1971) operate i n a p l u g - f l o w mode and use mechanical s u r f a c e a e r a t o r s f o r a e r a t i o n . Each r e a c t o r c o n t a i n s t e n a e r a t o r s . Reactors 5 t o 8 ( i n s t a l l e d i n 1985) operate i n a complete-mix mode and use j e t d i f f u s e r s and c e n t r i f u g a l blowers f o r a e r a t i o n . E f f l u e n t from the b i o r e a c t o r s i s t r e a t e d w i t h alum f o r phosphorus removal and i s then s e t t l e d i n twenty-four secondary c l a r i f i e r s p r i o r t o d i s c h a r g e t o the Bow R i v e r . P C ' s 1-4 DEGRITTED INFLUENT P C s 5-8 P C ' s 9-12 BIOREACTORS 1-4 ALUM S C ' s 1-12 i _ BIOREACTORS 5-8 ALUM S C ' s 13-24 1 DAF TO HEAD OF PLANT THICKENERS SLUDGE BLENDING DICESTORS DIGESTOR 7 1-5 ,9-12 CI •TREATED EFFLUENT IRRIGATION LAND APPLN SLUDCE LAGOONS DIGESTOR 6 DIGESTOR 8 I M FIGURE 4 . 1 - CALGARY BONNYBROOK PLANT FLOWSHEET (EXISTING) F I G U R E 4 .2 - C A L G A R Y B O N N Y B R O O K P L A N T L A Y O U T ( E X I S T I N G ! - 1 2 1 -S l u d g e f r o m p r i m a r y c l a r i f i e r s 1 t o 8 i s t h i c k e n e d i n t h r e e g r a v i t y t h i c k e n e r s . T h i c k e n e d p r i m a r y s l u d g e i s b l e n d e d w i t h s l u d g e f r o m p r i m a r y c l a r i f i e r s 9 t o 12 a n d WAS p r i o r t o d i s s o l v e d a i r f l o t a t i o n . D A F s l u d e i s t h e n a n a e r o b i c a l l y d i g e s t e d i n t w e l v e d i g e s t o r s . T h e d i g e s t i o n p r o c e s s i s e s s e n t i a l l y a s i n g l e s t a g e o p e r a t i o n . B l e n d e d s l u d g e i s f e d t o D i g e s t o r s 1 t o 6 , a n d 9 t o 1 2 . D i g e s t o r s 1 , 2 , 3 a n d 4 o v e r f l o w t o D i g e s t o r 7 . D i g e s t o r s 5 a n d 6 o v e r f l o w d i r e c t l y t o D i g e s t o r s 7 a n d 8 , r e s p e c t i v e l y . D i g e s t o r s 9 , 1 0 , 1 1 a n d 12 a l s o o v e r f l o w t o D i g e s t o r 7 . D i g e s t o r g a s i s r e c o v e r e d a n d i s u s e d f o r p o w e r g e n e r a t i o n a n d h e a t i n g . T h e d i g e s t e d s l u d g e i s t h e n p u m p e d f r o m D i g e s t o r s 7 a n d 8 t o s l u d g e l a g o o n s l o c a t e d o f f s i t e . D e w a t e r e d s l u d g e i s d i s p o s e d o f v i a l a n d a p p l i c a t i o n a n d l a g o o n s u p e r n a t a n t i s r e t u r n e d t o t h e h e a d o f t h e p l a n t . O v e r f l o w f r o m D i g e s t o r s 7 a n d 8 c a n b e d i r e c t e d t o t h e h e a d o f t h e p l a n t i f d e s i r e d . T h i s i s r a r e l y d o n e h o w e v e r . L a n d a p p l i c a t i o n o f t h e d e w a t e r e d s l u d g e i s c a r r i e d o u t i n t h e s u m m e r . S l u d g e i s a p p l i e d t o l o c a l a g r i c u l t u r a l l a n d v i a s u b s u r f a c e i n j e c t i o n . T h i s o p e r a t i o n i s k n o w n a s t h e C A L G R O p r o g r a m . A l l p i p i n g b e t w e e n t h e v a r i o u s u n i t o p e r a t i o n s i s l o c a t e d i n u n d e r g r o u n d t u n n e l s . T u n n e l s p r o v i d e c o n n e c t i o n s b e t w e e n t h e p r i m a r y c l a r i f i e r s , g r a v i t y t h i c k e n e r s , b i o r e a c t o r s , s e c o n d a r y c l a r i f i e r s a n d d i g e s t o r s . A l l s l u d g e p u m p s a r e l o c a t e d u n d e r g r o u n d i n t h e s e t u n n e l s . - 1 2 2 -S c r e w p u m p s a r e u s e d f o r R A S p u m p i n g . A s t h e s e p u m p s a r e e n c l o s e d , t h e y d o n o t a p p e a r t o p e r m i t t h e e n t r a i n m e n t o f l a r g e a m o u n t s o f D O . C o n c e n t r a t i o n s i n t h e R A S a r e n o t n o r m a l l y m e a s u r e d b u t i n t h e o p i n i o n o f t h e p l a n t s t a f f , a r e l i k e l y l e s s t h a n 1 . 0 m g / L ( B a r r e t t , 1 9 8 7 ) . A v i s u a l i n s p e c t i o n o f t h e o p e r a t i o n s e e m e d t o s u p p o r t t h i s . A u t o m a t i c DO c o n t r o l i s p r o v i d e d i n b o t h s e t s o f b i o r e a c t o r s . F e e d b a c k l o o p s a r e p r o v i d e d t o a d j u s t t h e p o s i t i o n o f t h e v a l v e s o n t h e a i r s u p p l y t a k e - o f f s i n t h e n e w p l a n t , a n d t h e l e v e l o f t h e t a n k s i n t h e o l d p l a n t . H o w e v e r , p r o b l e m s w i t h t h e DO p r o b e s h a v e m a d e t h i s s y s t e m i n o p e r a b l e . A l b e r t a E n v i r o n m e n t s t a n d a r d s f o r t h e p l a n t e f f l u e n t ( b a s e d o n m o n t h l y a v e r a g e s ) a r e a s f o l l o w s : B O D 5 - 2 5 m g / L T S S - 2 5 m g / L T P - 1 . 0 m g / L - P ( M a y t h r o u g h O c t o b e r ) 1 . 2 5 m g / L - P ( N o v e m b e r t h r o u g h A p r i l ) A v e r a g e c o n s t i t u e n t v a l u e s f o r t h e p l a n t i n f l u e n t ( b a s e d o n 1 9 8 5 / 8 6 m o n t h l y a v e r a g e s ) a r e l i s t e d b e l o w : - 1 2 3 -B O D 5 - 1 6 1 m g / L T S S - 1 5 3 m g / L T P - 4 . 5 m g / L - P v> N H 3 - 1 5 . 9 m g / L - N N 0 3 - 2 . 6 m g / L - N T m a x 1 9 ° C T m i n - 1 0 ° C T h e p r e s e n c e o f N 0 3 i n t h e i n f l u e n t s h o u l d b e n o t e d a s i t h a s a s i g n i f i c a n t e f f e c t o n t h e p r o c e s s d e s i g n o f t h e b i o r e a c t o r . T h e s o u r c e o f t h e N 0 3 i s n o t k n o w n . P e r f o r m a n c e o f t h e p l a n t h a s b e e n e x c e l l e n t w i t h t h e f o l l o w i n g a v e r a g e e f f l u e n t c o n c e n t r a t i o n s a n d c o m p l i a n c e r e s u l t s a c h i e v e d d u r i n g 1 9 8 5 a n d 1 9 8 6 : A v e r a g e E f f l u e n t C o n c e n t r a t i o n M o n t h l y C o m p l i a n c e s P a r a m e t e r ( m q / L ) ( M a x i m u m 2 4 ) B O D , . 1 1 24 o T S S 12 24 T P 0 . 7 5 2 4 N H 3 7 . 7 N / A N O . 1 3 . 8 N / A - 1 2 4 -T h e a b o v e f i g u r e s s h o w t h a t n i t r i f i c a t i o n t y p i c a l l y o c c u r s i n t h e B o n n y b r o o k p l a n t . A r e v i e w o f t h e m o n t h l y o p e r a t i n g s u m m a r i e s s u g g e s t s t h a t n i t r i f i c a t i o n c a n o c c u r f r o m M a y t h r o u g h t o F e b r u a r y . T h e p l a n t i s o p e r a t e d b y t h e C i t y o f C a l g a r y . A l a b o r a t o r y h a v i n g t h e c a p a b i l i t i e s t o p e r f o r m a l l a n a l y s e s f o r a B i o - P o p e r a t i o n , i s l o c a t e d o n s i t e . 4 . 1 . 2 R e t r o f i t M o d i f i c a t i o n s R e t r o f i t f l o w s h e e t s a n d l a y o u t d r a w i n g s f o r t h e p l a n t a r e p r e s e n t e d i n F i g u r e s 4 . 3 a n d 4 . 4 , r e s p e c t i v e l y . L a y o u t d r a w i n g s o f t h e r e t r o f i t t e d b i o r e a c t o r s a r e p r e s e n t e d i n F i g u r e 4 . 5 . A s s h o w n o n t h e s e d r a w i n g s , t h e f o l l o w i n g t h r e e m a j o r m o d i f i c a t i o n s w o u l d b e r e q u i r e d t o r e t r o f i t t h e B o n n y b r o o k p l a n t f o r B i o - P r e m o v a l : i ) P r o v i d e a d d i t i o n a l p r i m a r y s l u d g e g r a v i t y t h i c k e n e r s a n d m o d i f y t h e e x i s t i n g t h i c k e n e r s t o a c c o m m o d a t e p r i m a r y s l u d g e f e r m e n t a t i o n . i i ) M o d i f y t h e b i o r e a c t o r s t o a c c o m m o d a t e a n a n o x i c / a n a e r o b i c / a e r o b i c s e q u e n c e . P C 3 1-4 BIOREACTORS 1-4 DEGRITTED INFLUENT P C ' s 5-8 P C ' s 9-12 — i — r . i i i i ; i i BIOREACTORS 5-8 - i — r i • i i j i | I T D A F THICKENERS 1 ,2 ,3 FERMENTER5 1,2 FERMENTERS 3 ,4 SLUDCE BLENDING AL™ S C ' s 1-12 ALUM S C ' s 13-24 V C I TREATED EFFLUENT LIME \ i—i r i " Y x — k DIGESTORS DIGESTOR 7 1 - 5 , 9 - 1 2 IRRIGATION L A N D A P P L N DIGESTOR 6 DIGESTOR 8 SLUDGE LAGOONS DENOTES BIO-P MODIFICATION F I G U R E 4.3 ~ C A L G A R Y B O N N Y B R O O K R E T R O F I T F L O W S H E E T TREATED EFFLUENT SC 'S 1 - 12 F I G U R E 4.4 - C A L G A R Y B O N N Y B R O O K R E T R O F I T L A Y O U T FROM P C ' » FERMENTER SUPERNATANT BIOREACTORS 5 - 8 6 6 . 5 a FROM BLOWERS c-o— e l 1 6 i»0 4 o - ~ - o 1 . -X C E L L S T A T U S 1 , 2 , 3 U N A E R A T E D 6 , 5 , 6 U N A E R A T E D / A E R A T E D 7 A E R A T E D HRT (HRS) 0 . 5 0 . 5 4 . 5 . T 0 " S C ' s O - J E T D I F F U S E R $ - M I X E R (I)- M E C H A N I C A L M - / A E R A T O R FROM P C ' i C E L L 1 .2 3 . 4 B I O R E A C T O R S 1 - 4 36 n T O S C 1 © t e s t © i t RAS © -2 © e e e . S T A T U S U N A E R A T E D U N A E R A T E D / A E R A T E D A E R A T E D A E R A T E D HRT ( H R S ) 0 . 6 9 0 . 6 9 0 . 6 9 3 . 5 to FERMENTER SUPERNATANT F I G U R E 4.5 - C A L G A R Y B O N N Y B R O O K R E T R O F I T B I O R E A C T O R L A Y O U T - 128 -i i i ) P r o v i d e f a c i l i t i e s f o r t h e l i m e t r e a t m e n t o f t h e l a g o o n s u p e r n a t a n t t o p r e v e n t i n t e r n a l p h o s p h o r u s r e c y c l i n g . T h e s e f a c i l i t i e s w o u l d b e l o c a t e d a t t h e e x i s t i n g l a g o o n s i t e . T h e p r e s e n c e o f n i t r a t e s i n t h e p l a n t i n f l u e n t w o u l d n e c e s s i t a t e t h e u s e o f g r a v i t y t h i c k e n i n g f o r p r i m a r y s l u d g e f e r m e n t a t i o n i n c o n j u n c t i o n w i t h t h e a n o x i c / a n a e r o b i c / a e r o b i c p r o c e s s . T h e c r e a t i o n o f a n a n o x i c z o n e a t t h e f r o n t o f t h e b i o r e a c t o r s w o u l d b e r e q u i r e d t o d e n i t r i f y t h e n i t r a t e s i n t h e i n f l u e n t . T h e u s e o f g r a v i t y t h i c k e n i n g w o u l d a l l o w f o r t h e i s o l a t i o n o f V F A - r i c h s u p e r n a t a n t , s u c h t h a t i t c o u l d b e i n t r o d u c e d a t a p o i n t i n t h e n o n - a e r a t e d z o n e o f t h e b i o r e a c t o r w h e r e d e n i t r i f i c a t i o n w a s c o m p l e t e . T h e c o m b i n e d u s e o f g r a v i t y t h i c k e n i n g a n d t h e a n o x i c / a n a e r o b i c / a e r o b i c p r o c e s s w o u l d a l s o p r o v i d e g o o d f l e x i b i l i t y i n d e a l i n g w i t h n i t r i f y i n g a n d n o n - n i t r i f y i n g c o n d i t i o n s . D u r i n g t h e w i n t e r , w h e n m i n i m a l n i t r i f i c a t i o n o c c u r s , t h e a n o x i c z o n e w o u l d b e s m a l l ( 0 . 5 h o u r H R T ) a n d t h e r e f o r e , t h i c k e n e r s u p e r n a t a n t w o u l d b e i n t r o d u c e d r e l a t i v e l y c l o s e t o t h e h e a d o f t h e t a n k . D u r i n g t i m e s w h e n n i t r i f i c a t i o n o c c u r s , t h e a n o x i c z o n e w o u l d b e l a r g e r t o a c c o m m o d a t e d e n i t r i f i c a t i o n o f t h e n i t r a t e s i n t h e R A S , a n d h e n c e t h e t h i c k e n e r s u p e r n a t a n t w o u l d b e i n t r o d u c e d f a r t h e r d o w n t h e b i o r e a c t o r . - 1 2 9 -F o u r a d d i t i o n a l g r a v i t y t h i c k e n e r s w o u l d b e p r o v i d e d i n t h e B i o - P r e t r o f i t a s t h e e x i s t i n g t h i c k e n e r s d o n o t p r o v i d e s u f f i c i e n t r e t e n t i o n t i m e a t t h e d e s i g n p r i m a r y c l a r i f i e r u n d e r f l o w r a t e . T h e e x i s t i n g t h i c k e n e r s w o u l d f e r m e n t t h e s l u d g e f r o m p r i m a r y c l a r i f i e r s 1 t o 4, a n d t h e n e w t h i c k e n e r s w o u l d b e u s e d f o r t h e s l u d g e f r o m p r i m a r y c l a r i f i e r s 5 t o 1 2 . H o w e v e r , b e f o r e c o m m i t t i n g t o t h e c o n s t r u c t i o n o f t h e n e w t h i c k e n e r s , i t w o u l d b e a d v i s a b l e t o t e s t t h e c a p a b i l i t y o f t h e e x i s t i n g t h i c k e n e r s t o p r o d u c e V F A ' s . P o s i t i v e r e s u l t s f r o m t h e s e t e s t s c o u l d e l i m i n a t e t h e r e q u i r e m e n t s f o r t h e a d d i t i o n a l t h i c k e n e r s . T h i c k e n e r s w o u l d b e l o c a t e d b e l o w g r a d e t o m i n i m i z e h e a t l o s s . P i p i n g f r o m t h e n e w t h i c k e n e r s t o t h e o t h e r u n i t o p e r a t i o n s w o u l d b e b u r i e d w h e r e t u n n e l s a r e n o t a v a i l a b l e . I t w a s n o t f e l t t h a t t h e s m a l l n u m b e r o f p i p e s a s s o c i a t e d w i t h t h e f e r m e n t e r o p e r a t i o n , w a r r a n t e d t h e c o n s t r u c t i o n o f n e w t u n n e l s . T h e t h i c k e n e r s u p e r n a t a n t l i n e s t o t h e b i o r e a c t o r s w o u l d b e r u n i n t h e p r i m a r y e f f l u e n t c h a n n e l , w h e r e p o s s i b l e . S u p e r n a t a n t , r e c y c l e a n d w a s t a g e p u m p s f o r t h e n e w t h i c k e n e r s w o u l d b e l o c a t e d i n n e w a b o v e - g r a d e , h e a t e d p u m p h o u s e s . N e w s u p e r n a t a n t a n d r e c y c l e p u m p s w o u l d b e r e q u i r e d f o r t h e e x i s t i n g t h i c k e n e r s . T h e s e w o u l d b e l o c a t e d i n t h e e x i s t i n g t u n n e l s e r v i c i n g t h e s e t h i c k e n e r s . N e w p i p i n g f o r t h e s u p e r n a t a n t a n d r e c y c l e p u m p s w o u l d a l s o b e r o u t e d w i t h i n t h i s - 130 -t u n n e l . The e x i s t i n g pumps and p i p i n g from the t h i c k e n e r s t o the sludge b l e n d i n g f a c i l i t y were found t o be adequate f o r wasting under a Bio-P s c e n a r i o . T h e r e f o r e , no m o d i f i c a t i o n s t o these would be r e q u i r e d . M o d i f i c a t i o n s t o b i o r e a c t o r s 1 t o 4 would i n v o l v e s h u t t i n g down the e x i s t i n g a e r a t o r s and i n s t a l l i n g mixers i n the proposed anoxic and anaerobic zones. Other m o d i f i c a t i o n s would i n c l u d e compartmentalizing the f i r s t pass o f the r e a c t o r s ; i n s t a l l i n g new DO probes t o r e p l a c e the n o n - f u n c t i o n i n g e x i s t i n g ones; and i n s t a l l i n g ORP probes and r e c o r d e r s . M o d i f i c a t i o n s t o b i o r e a c t o r s 5 t o 8 would i n c l u d e the c o n v e r s i o n o f the r e a c t o r s from completely-mixed t o pl u g - f l o w o p e r a t i o n s . T h i s would i n v o l v e the i n s t a l l a t i o n o f d i v i d i n g w a l l s (see F i g u r e 4.5) and the re-arrangement of the j e t d i f f u s e r s and t h e i r a s s o c i a t e d p i p i n g t o accommodate the compartmentalized l a y o u t . Other m o d i f i c a t i o n s would i n c l u d e the i n s t a l l a t i o n o f mixers i n the anoxic and an a e r o b i c zones; the replacement of the e x i s t i n g DO probes; and the i n s t a l l a t i o n o f ORP probes and r e c o r d e r s . The c o n t i n u e d use of the e x i s t i n g sludge h a n d l i n g f a c i l i t i e s combined w i t h the lime treatment o f the lagoon supernatant was deemed t o be the most p r a c t i c a l method of h a n d l i n g the Bio-P sludge. C o n s i d e r a t i o n was g i v e n t o pumping - 1 3 1 -t h e t h i c k e n e d WAS d i r e c t l y t o t h e l a g o o n s a r o u n d t h e a n a e r o b i c d i g e s t o r s . H o w e v e r , i t w a s f e l t t h a t a n a e r o b i c c o n d i t i o n s w o u l d p r e v a i l i n t h e l a g o o n s a n d h e n c e , p h o s p h o r u s r e l e a s e w o u l d s t i l l o c c u r . I n a d d i t i o n , b e c a u s e t h e s l u d g e w o u l d n o t b e d i g e s t e d , s o l i d s a p p l i c a t i o n r a t e s f o r l a n d a p p l i c a t i o n o f t h e l a g o o n s l u d g e w o u l d b e r e d u c e d b y a p p r o x i m a t e l y 8 0 p e r c e n t ( A l b e r t a E n v i r o n m e n t , 1 9 8 2 ) . F u r t h e r m o r e , l o s t d i g e s t o r g a s p r o d u c t i o n w o u l d r e s u l t i n i n c r e m e n t a l o p e r a t i n g c o s t s o f a p p r o x i m a t e l y $ 4 0 0 , 0 0 0 p e r y e a r f o r n a t u r a l g a s m a k e - u p . S l u d g e c o m p o s t i n g w a s a l s o c o n s i d e r e d a s a n a l t e r n a t i v e t o a n a e r o b i c d i g e s t i o n a n d l a g o o n d e w a t e r i n g . I t w a s e s t i m a t e d t h a t a p p r o x i m a t e l y 2 0 h a o f l a n d w o u l d b e r e q u i r e d f o r t h e c o m p o s t i n g o f t h e W A S . W h i l e c o m p o s t i n g w o u l d r e s u l t i n l o s t d i g e s t o r g a s p r o d u c t i o n , i t w o u l d p e r m i t t h e u s e o f t h e d i g e s t o r s f o r p r i m a r y s l u d g e f e r m e n t a t i o n . H o w e v e r , t h e u s e o f c o m p o s t i n g w o u l d r e q u i r e a t o t a l r e - o r g a n i z a t i o n o f t h e s l u d g e h a n d l i n g o p e r a t i o n s . I n a d d i t i o n , a s u i t a b l e s u p p l y o f b u l k m a t e r i a l ( e . g . w o o d c h i p s ) w o u l d h a v e t o b e l o c a t e d . T h e r e f o r e , t h e u s e o f c o m p o s t i n g w a s n o t s e l e c t e d f o r t h i s e v a l u a t i o n . I t m a y h o w e v e r , w a r r a n t f u r t h e r s t u d y . P r o b l e m s a s s o c i a t e d w i t h l a n d a p p l i c a t i o n o f t h e c o m b i n e d l i m e / a n a e r o b i c s l u d g e a r e n o t a n t i c i p a t e d . I n f a c t , p r o v i n c i a l g u i d e l i n e s s u g g e s t t h a t t h e a d d i t i o n o f l i m e m a y i m p r o v e t h e m a r k e t f o r t h e s l u d g e . A l b e r t a E n v i r o n m e n t ( 1 9 8 2 ) n o t e s t h a t l i m e - b a s e d s e w a g e s l u d g e s c a n b e a p p l i e d t o s o i l s o f - 1 3 2 -l o w e r p H t h a n t h o s e t o w h i c h c o n v e n t i o n a l s l u d g e s c a n b e a p p l i e d t o . T h i s i s b e c a u s e t h e h i g h p H o f t h e l i m e s l u d g e r e s t r i c t s t h e s o l u b i l i z a t i o n o f m e t a l s i n t h e s l u d g e . T h e r e f o r e , t h e a d d i t i o n o f l i m e m a y a c t u a l l y i m p r o v e s l u d g e d i s p o s a l o p e r a t i o n s . I n d e v e l o p i n g t h e e s t i m a t e f o r t h e l i m e t r e a t m e n t f a c i l i t y i t w a s a s s u m e d t h a t t h e a l k a l i n i t y o f t h e l a g o o n s u p e r n a t a n t i s 5 0 0 m g / L C a C 0 3 . A s p r e v i o u s l y m e n t i o n e d , t h i s w a s b a s e d o n f i g u r e s o b t a i n e d f r o m t h e S a s k a t o o n p l a n t w h e r e l a g o o n s u p e r n a t a n t a l k a l i n i t i e s r a n g e f r o m 3 0 0 t o 4 0 0 m g / L C a C 0 3 . A c o m p a r i s o n o f t h e o p e r a t i n g p a r a m e t e r s f o r a B i o - P r e m o v a l f a c i l i t y v e r s u s t h o s e f o r t h e e x i s t i n g c h e m i c a l p h o s p h o r u s r e m o v a l f a c i l i t y i s p r e s e n t e d i n T a b l e 4 . 1 . A s s h o w n i n t h i s t a b l e , B i o - P r e m o v a l w o u l d r e s u l t i n r e d u c e d a l u m c o n s u m p t i o n , d i g e s t o r g a s p r o d u c t i o n , a n d o x y g e n d e m a n d u n d e r n i t r i f y i n g c o n d i t i o n s . D i g e s t o r g a s p r o d u c t i o n w o u l d b e r e d u c e d b e c a u s e o f t h e s o l u b i l i z a t i o n o f V S S i n t h e f e r m e n t e r a n d t h e s u b s e q u e n t o x i d a t i o n o f t h e s o l u b i l i z e d p r o d u c t s i n t h e b i o r e a c t o r . T h i s a l s o e x p l a i n s t h e i n c r e a s e d c a r b o n a c e o u s o x y g e n d e m a n d a s s o c i a t e d w i t h B i o - P r e m o v a l . I t s h o u l d b e n o t e d t h a t a s m a l l q u a n t i t y o f a l u m ( 1 0 m g / L ) w o u l d b e r e q u i r e d t o r e d u c e s o l u b l e p h o s p h o r u s l e v e l s s u c h t h a t a n e f f l u e n t T P o f 1 . 0 m g / L c a n b e a c h i e v e d . - 1 3 3 -T a b l e 4 . 1 a l s o i n d i c a t e s t h a t a B i o - P f a c i l i t y w o u l d c o n s u m e m o r e l i m e a n d e l e c t r i c i t y , w o u l d r e q u i r e a d d i t i o n a l o p e r a t i o n s s t a f f , a n d w o u l d p r o d u c e m o r e s l u d g e t h a n t h e e x i s t i n g f a c i l i t y . T h e r e q u i r e m e n t f o r l i m e t r e a t m e n t o f t h e l a g o o n s u p e r n a t a n t i s r e s p o n s i b l e f o r t h e i n c r e a s e d s l u d g e p r o d u c t i o n . A d d i t i o n a l o p e r a t i n g s t a f f a r e r e q u i r e d t o o p e r a t e a n d m a i n t a i n t h e l i m e t r e a t m e n t f a c i l i t y a n d t h e f e r m e n t e r o p e r a t i o n , a n d t o c a r r y o u t t h e a d d i t i o n a l l a b o r a t o r y a n a l y s i s r e q u i r e d f o r a B i o - P f a c i l i t y . 4 . 1 . 3 C o s t A n a l y s i s A s u m m a r y o f t h e i n c r e m e n t a l c a p i t a l c o s t s a s s o c i a t e d w i t h B i o - P r e m o v a l i s p r e s e n t e d i n T a b l e 4 . 2 . A s s h o w n , t h e t o t a l i n c r e m e n t a l c a p i t a l c o s t f o r a B i o - P r e t r o f i t w o u l d b e a p p r o x i m a t e l y $ 5 , 3 6 8 , 0 0 0 . A l a r g e p o r t i o n o f t h i s ( $ 2 , 4 0 4 , 0 0 ) i s a s s o c i a t e d w i t h t h e c o n s t r u c t i o n o f n e w g r a v i t y t h i c k e n e r s f o r p r i m a r y s l u d g e f e r m e n t a t i o n . T h r e f o r e , t h e r e i s p o t e n t i a l f o r s i g n i f i c a n t s a v i n g s i f i t c o u l d b e d e m o n s t r a t e d t h a t t h e e x i s t i n g t h i c k e n e r s c a n p r o d u c e s u f f i c i e n t V F A ' s f o r g o o d p h o s p h o r u s r e m o v a l . - 1 3 4 -P A R A M E T E R B I O - P C A S E C H E M I C A L P C A S E A l u m C o n s u m p t i o n ( k g / d ) 4 , 6 0 0 2 9 , 9 7 0 L i m e C o n s u m p t i o n ( k g / d ) 4 , 8 9 2 S l u d g e P r o d u c t i o n - M a s s ( k g / d ) 5 0 , 0 4 9 4 7 , 5 3 0 - V o l u m e ( m 3 / d ) 4 3 5 4 1 3 O x y g e n D e m a n d ( k g / d ) - w / o N i t r i f i c a t i o n 3 9 , 6 8 4 3 7 , 0 3 5 - w / N i t r i f i c a t i o n 6 2 , 9 6 0 6 9 , 7 3 3 3 M e t h a n e P r o d u c t i o n (m / d ) 2 7 , 8 2 8 3 1 , 1 6 8 I n c r e m e n t a l P o w e r 1 " + 1 4 3 C o n s u m p t i o n (kw) I n c r e m e n t a l O p e r a t i o n s S t a f f +2 T A B L E 4 . 1 - C A L G A R Y B O N N Y B R O O K O P E R A T I O N S C O M P A R I S O N 2 ' I n c l u d e s p o w e r s a v i n g s f r o m r e d u c e d o x y g e n d e m a n d . B a s e d o n a n i n f l u e n t f l o w o f 4 5 0 , 0 0 0 m / d . - 135 -A s u m m a r y o f t h e i n c r e m e n t a l o p e r a t i n g c o s t s f o r B i o - P r e m o v a l i s p r e s e n t e d i n T a b l e 4.3. A s i n d i c a t e d , t h e u s e o f B i o - P r e m o v a l w o u l d r e s u l t i n a n a n n u a l s a v i n g s o f a p p r o x i m a t e l y $1,490,000. T h i s i s e s s e n t i a l l y a t t r i b u t a b l e t o l a r g e r e d u c t i o n s i n a l u m c o n s u m p t i o n . T h e c o s t s a s s o c i a t e d w i t h i n c r e a s e d s l u d g e p r o d u c t i o n w e r e b a s e d o n t h e a s s u m p t i o n t h a t a d d i t i o n a l s l u d g e p r o d u c e d i n a B i o - P o p e r a t i o n w o u l d b e a p p l i e d t o t h e l a n d v i a t h e CALGRO o p e r a t i o n . T h e r e f o r e , c o s t s w e r e c a l c u l a t e d u s i n g t h e u n i t c o s t s f o r t h e 1986 C A L G R O o p e r a t i o n ( $ 1 1 2 / t o n n e o f s l u d g e d i s p o s e d ) . A n o t h e r o p t i o n f o r e s t i m a t i n g t h e s e c o s t s w o u l d b e t o a s s u m e t h a t t h e i n c r e m e n t a l s l u d g e p r o d u c t i o n i s n o t a p p l i e d t o t h e l a n d a n d h e n c e , i s a l l o w e d t o b u i l d - u p i n t h e l a g o o n s . I n t h i s c a s e , t h e c o s t o f i n c r e a s e d s l u d g e p r o d u c t i o n w o u l d b e t h e a m o r t i z e d c o s t o f c o n s t r u c t i n g n e w l a g o o n s a t a n e a r l i e r d a t e . T h i s o p t i o n w a s n o t s e l e c t e d a s i t w a s d e e m e d t o o d i f f i c u l t t o s p e c u l a t e o n f u t u r e l a n d a p p l i c a t i o n r a t e s a n d l a g o o n s i t e s . TOTAL MODIFICATION i TEH SPECIFICATION ARTERIAL BULK INSTALLEC DUANTITV COST INSTALLATION FACTOR COST <*> MANHOURS <*> 4 360288 1.64 727719 SAO H3 146500 5130 313470 ST60 M3 1152 35712 6 26200 3.6 111446 1575 H 206798 7607 450894 9 17100 144 22248 7 28344 3.8 115967 3 17100 144 22248 A 22000 3.8 86944 3 17100 144 22248 167 H2 71827 225 M 41763 1249 82165 225 H 29543 1087 64413 3000 M2 123000 4800 276720 1511 N3 415525 14355 877136 16 16O0O 2.1 34944 6 2800 2.1 6115 80 280000 1.34 390208 660 M 115544 4250 251928 16 56000 2. 1 122304 2 58000 2.2 132704 2 32000 1.23 40934 1 . 5100 6 31624 1 1691 1.34 2357 1882 3.8 7438 1 35000 2.6 94640 1 1691 1.34 2357 1800 3.8 7114 1 9100 5.2 49213 1 1275 1.34 1777 1 904 1.34 1260 • 1 48962 1.84 93694 30 8250 285 2.5 17415 103 21 639 2 1882 3.8 7438 500 M2 215000 SUB-TOTAL 4792459 ENOINEERINQ 575095 UFA SUPPLV FERMENTER MECHANICAL FERMENTER TANK 2. BIORERCTOR 3. SUPERNATANT PUMPS 4. SUPERNATANT PI PI NO 5. SUPNT PUMP INSTN 6. RECVCLE PUMPS 7. RECVCLE INSTN 6. HASTE PUMPS 10. UASTE PUMP INSTN 11. PUMPHOUSES 12. PC UNOERFLOU PIPINO 13. FERM UASTE PIPING 14. AREA LIGHTING 1. COMPARTMENTRLIZATION 2. ORP PROBES 3. ORP RECORDERS 4. MIXERS 5. NEM REACTOR PIPINO 6. NEM DO PROBES H SUD, 4.0 kU 12.6 kU kU 20.0 H DIAM. 3.5 CONCRETE EXCAVATION 45 L / s , 20 M TDH, 150 MM ASTM A53 AS PER FIGURE 3.2 45 L / s , 15 H TDH, 9.5 AS PER FIGURE 3.2 45 L / s , 26 M TDH, 16.4 kU AS PER FIGURE 3.2 2 - 11.6 H M 7.2 N H 5 H 250 MM ASTM A53 150 MM ASTM A53 CONRETE PARTITIONS 2.4 kU 150 MM ASTM R53 LIME TREATMENT OF DIOESTOR SUPERNATANT 1. STORROE SILOS 2. CHEMICAL FEEDER 3. MIX TANK 4. MIX TANK MIXER 5. HOLDING TANK FD PUMPS 6. HOLDING TANK 7. HOLDING TANK MIXER 8. HOLDING TANK PUMPS 10. RAPID MIX/FLOCCN TNK 11. RAPID MIX MIXER 12. FL0CCN MIXER 13. CLARIFIER MECHANICAL 14. CLARIFIER TANK 15. LIME SLUDOE 16. BUILDING PUMPS STEEL 14/ EPOXV LINER, 158 M3 ROTARV TVPE, 612 kg/hr STEEL, 1.7 M 3 0.64 kU 5.6 L / C , 6.0 M TDH, 0.5 kU 163 M3 0.64 kU 1.0 L/s, 3.0 H TDH, 0.10 kU 5.8 M3 0.25 kU 0.023 kU 6.6 M DIAH, 3.0 M SUD, 2.0 kU CONCRETE EXCAVATION 1.6 L/», 10.0 M TDH, 0.30 kU 25 M • 20 H M 8H TOTAL 5367554 T A B L E 4 . 2 - C A L G A R Y B O N N Y B R O O K C A P I T A L C O S T S U M M A R Y - 1 3 7 -I N C R E M E N T A L I T E M 1 . A l u m 2 . L i m e 3 . N a t u r a l G a s 4 . S l u d g e D i s p o s a l 5 . P o w e r 6 . O p e r a t i o n s S t a f f 7 . M a i n t e n a n c e M a t e r i a l s T O T A L A N N U A L C O S T ( $ 1 , 9 9 1 , 0 0 0 ) 1 7 3 , 0 0 0 8 8 , 0 0 0 1 0 3 , 0 0 0 2 0 , 0 0 0 9 4 , 0 0 0 2 3 , 0 0 0 l £ l ^ 4 9 0 J _ 0 0 0 1 T A B L E 4 . 3 - C A L G A R Y B O N N Y B R O O K O P E R A T I N G C O S T S U M M A R Y - 1 3 8 -B a s e d o n t h e s e e s t i m a t e s , t h e s i m p l e p a y b a c k p e r i o d f o r t h e c a p i t a l i n v e s t m e n t i s 3 . 6 y e a r s . I R R ' s f o r t h e i n v e s t m e n t f o r v a r i o u s p r o j e c t l i v e s a r e a s f o l l o w s : P R O J E C T L I F E ( y e a r s ) . I R R f%> 5 1 3 . 9 1 0 2 5 . 6 1 5 2 7 . 3 2 0 2 7 . 6 4 . 2 E d m o n t o n G o l d B a r W a s t e w a t e r T r e a t m e n t P l a n t 4 . 2 . 1 P l a n t D e s c r i p t i o n T h e G o l d B a r W a s t e w a t e r T r e a t m e n t P l a n t i s t h e l a r g e r o f t h e t w o s e w a g e t r e a t m e n t p l a n t s w h i c h s e r v i c e t h e C i t y o f E d m o n t o n a n d t h e s u r r o u n d i n g c o m m u n i t i e s . L o c a t e d i n t h e c i t y o n t h e N o r t h S a s k a t c h e w a n R i v e r , t h e p l a n t c u r r e n t l y s e r v e s a p o p u l a t i o n o f 5 6 0 , 0 0 0 . T h e d e s i g n c a p a c i t y o f t h e p l a n t i s 3 3 4 0 , 0 0 0 m / d b a s e d o n a v e r a g e d a i l y f l o w . T h e p l a n t u s e s t h e a c t i v a t e d s l u d g e p r o c e s s a n d c o n t a i n s s c r e e n i n g , g r i t r e m o v a l , p r i m a r y s e d i m e n t a t i o n , d i f f u s e d a i r a e r a t i o n , s e c o n d a r y s e d i m e n t a t i o n , s i n g l e s t a g e a n a e r o b i c d i g e s t i o n a n d c h l o r i n a t i o n u n i t o p e r a t i o n s . D i g e s t e d g a s i s - 1 3 9 -r e c o v e r e d a n d i s u s e d f o r h e a t i n g a n d p o w e r g e n e r a t i o n . D i g e s t e d s l u d g e i s p u m p e d t o s l u d g e l a g o o n s , l o c a t e d a p p r o x i m a t e l y 12 km f r o m t h e p l a n t , f o r d e w a t e r i n g . D e w a t e r e d s l u d g e i s d i s p o s e d o f v i a l a n d a p p l i c a t i o n . F l o w s h e e t s a n d l a y o u t d r a w i n g s o f t h e e x i s t i n g f a c i l i t y a r e p r e s e n t e d i n F i g u r e s 4 . 6 a n d 4 . 7 , r e s p e c t i v e l y . A s s h o w n i n t h e d r a w i n g s , t h e p l a n t c o n t a i n s e i g h t p r i m a r y s e d i m e n t a t i o n t a n k s , b i o r e a c t o r s a n d s e c o n d a r y c l a r i f i e r s . E a c h b i o r e a c t o r i s 9 7 . 5 m l o n g b y 2 4 . 7 m w i d e a n d i s d i v i d e d i n t o f o u r 6 . 1 7 m w i d e p a s s e s . T h e b i o r e a c t o r s c a n b e o p e r a t e d i n e i t h e r p l u g - f l o w o r s t e p - f e e d m o d e s . A i r i s s u p p l i e d b y c e n t r a l l y l o c a t e d r a d i a l b l o w e r s . A u t o m a t i c DO c o n t r o l i s p r o v i d e d w i t h a f e e d b a c k l o o p c o n t r o l l i n g m o d u l a t i n g v a l v e s o n t h e a i r s u p p l y h e a d e r s u s i n g DO m e a s u r e m e n t s f r o m DO p r o b e s l o c a t e d i n t h e b i o r e a c t o r s . O v e r f l o w f r o m t h e d i g e s t o r s a n d s u p e r n a t a n t f r o m t h e s l u d g e l a g o o n s a r e b o t h r e t u r n e d t o t h e h e a d o f t h e p l a n t . D i g e s t o r o v e r f l o w c a n b e d i v e r t e d t o t h e s l u d g e l a g o o n s i f r e q u i r e d . A l l p i p i n g b e t w e e n t h e u n i t o p e r a t i o n s i s l o c a t e d i n u n d e r g r o u n d t u n n e l s . T u n n e l s a r e a v a i l a b l e t o i n t e r c o n n e c t t h e p r i m a r y c l a r i f i e r s , t h e b i o r e a c t o r s , t h e s e c o n d a r y c l a r i f i e r s a n d t h e d i g e s t o r s . BIOREACTORS (8) CI TREATED EFFLUENT O DICESTORS (6) F I G U R E 4 . 6 - E D M O N T O N G O L D B A R P L A N T F L O W S H E E T ( E X I S T I N G ) - 1 4 2 -T h e p l a n t d i s c h a r g e s t r e a t e d e f f l u e n t t o t h e N o r t h S a s k a t c h e w a n R i v e r . A l b e r t a E n v i r o n m e n t s t a n d a r d s f o r t h i s e f f l u e n t a r e c u r r e n t l y a s f o l l o w s : B O D 5 - 2 5 m g / L ( b a s e d o n m o n t h l y m e a n ) T S S - 2 5 m g / L ( b a s e d o n m o n t h l y m e a n ) I n f l u e n t t o t h e p l a n t i s t y p i c a l o f C a n a d i a n m u n i c i p a l i t i e s . A v e r a g e c o n s t i t u e n t v a l u e s ( b a s e d o n 1 9 8 5 / 8 6 m o n t h l y a v e r a g e s ) f o r t h e r a w s e w a g e a r e a s f o l l o w s : B O D 5 - 2 1 4 m g / L S S - 2 3 5 m g / L T P - 7 . 3 m g / L - P T K N - 3 4 . 0 m g / L - N N H 3 - 2 4 . 0 m g / L - N T m a x - 2 0 ° C T m i n - 7 ° C P e r f o r m a n c e o f t h e p l a n t h a s b e e n e x c e l l e n t w i t h e f f l u e n t B 0 D 5 ' s a n d T S S ' s a v e r a g i n g a p p r o x i m a t e l y 12 m g / L a n d 10 m g / L , r e s p e c t i v e l y . E f f l u e n t N H ^ r e c o r d s i n d i c a t e t h a t n i t r i f i c a t i o n c a n o c c u r f r o m M a r c h t o O c t o b e r i n s p i t e o f t h e r e l a t i v e l y s h o r t s l u d g e a g e ( 5 - 7 d a y s ) a t w h i c h t h e p l a n t o p e r a t e s ( S h i v j i , 1 9 8 7 ) . - 1 4 3 -T h e p l a n t i s o p e r a t e d b y t h e C i t y o f E d m o n t o n . A l a b o r a t o r y w i t h t h e c a p a b i l i t y t o p e r f o r m a l l a n a l y s e s r e q u i r e d f o r a B i o - P o p e r a t i o n i s l o c a t e d o n s i t e . T h e p o t e n t i a l f o r p h o s p h o r u s r e m o v a l s t a n d a r d s b e i n g i m p o s e d o n d i s c h a r g e s t o t h e N o r t h S a s k a t c h e w a n R i v e r c a u s e d t h e C i t y t o s t u d y v a r i o u s o p t i o n s f o r p h o s p h o r u s r e m o v a l . A s p a r t o f t h i s s t u d y , t h e C i t y , i n c o n j u n c t i o n w i t h A l b e r t a E n v i r o n m e n t , c o n d u c t e d a p i l o t s t u d y f o r 1 6 m o n t h s i n 1 9 8 5 , 1 9 8 6 a n d 1 9 8 7 t o i n v e s t i g a t e t h e f e a s i b i l i t y o f u s i n g B i o - P r e m o v a l ( S h i v j i , 1 9 8 7 ) . T h e s t u d y i n v o l v e d o p e r a t i n g o n e o f t h e b i o r e a c t o r s i n a n a n a e r o b i c / a e r o b i c p l u g - f l o w s e q u e n c e . R e s u l t s w e r e p r o m i s i n g a s a v e r a g e m o n t h l y T P c o n c e n t r a t i o n s b e l o w 2 . 0 m g / L w e r e a c h i e v e d 75% o f t h e t i m e , a n d c o n c e n t r a t i o n s b e l o w 1 . 0 m g / L w e r e a c h i e v e d 55% o f t h e t i m e . O f p a r t i c u l a r i n t e r e s t , i t w a s o b s e r v e d t h a t g o o d p h o s p h o r u s r e m o v a l ( e f f l u e n t T P < 1 . 0 m g / L ) w a s g e n e r a l l y e x p e r i e n c e d f o r f i v e t o s i x c o n s e c u t i v e d a y s , f o l l o w e d b y p o o r p h o s p h o r u s r e m o v a l f o r o n e t o t w o d a y s . T h e s e p e r i o d s o f p o o r p e r f o r m a n c e g e n e r a l l y s t a r t e d o n M o n d a y o r T u e s d a y . S h i v j i a t t r i b u t e s t h i s t o l o w s t r e n g t h s e w a g e p r o c e s s e d o n t h e w e e k e n d s . I t w a s a l s o n o t e d ( Y e e , 1 9 8 7 ) t h a t t w o b r e w e r i e s i n E d m o n t o n d i s c h a r g e w a s t e w a t e r t o t h e G o l d B a r p l a n t f r o m M o n d a y t o F r i d a y . B r e w e r y w a s t e w a t e r t y p i c a l l y c o n t a i n s f e r m e n t a t i o n p r o d u c t s i n c l u d i n g V F A ' s . T h e r e f o r e , i t i s p o s t u l a t e d t h a t t h e p e r i o d s o f p o o r p h o s p h o r u s r e m o v a l w e r e a t t r i b u t a b l e t o i n s u f f i c i e n t V F A ' s p r e s e n t i n t h e i n f l u e n t a n d , h e n c e , p r i m a r y s l u d g e f e r m e n t a t i o n w o u l d b e r e q u i r e d f o r a B i o - P r e t r o f i t . - 1 4 4 -4 . 2 . 2 R e t r o f i t M o d i f i c a t i o n s F o r t h e p u r p o s e s o f t h i s s t u d y , i t w a s a s s u m e d t h a t e f f l u e n t T P c o n c e n t r a t i o n s o f l e s s t h a n 1 . 0 m g / L w o u l d b e r e q u i r e d . I t w a s a l s o a s s u m e d t h a t a l u m w o u l d b e u s e d f o r a c h e m i c a l p h o s p h o r u s r e m o v a l p r o c e s s . R e t r o f i t f l o w s h e e t s a n d l a y o u t d r a w i n g s f o r t h e G o l d B a r p l a n t a r e p r e s e n t e d i n F i g u r e s 4 . 8 a n d 4 . 9 . r e s p e c t i v e l y . A l a y o u t d r a w i n g o f a t y p i c a l b i o r e a c t o r i s p r e s e n t e d i n F i g u r e 4 . 1 0 . A s s h o w n i n F i g u r e 4 . 8 , t h e f o l l o w i n g t h r e e m a j o r m o d i f i c a t i o n s w o u l d b e r e q u i r e d t o r e t r o f i t t h e G o l d B a r p l a n t f o r B i o - P r e m o v a l : i ) P r o v i d e p r i m a r y s l u d g e f e r m e n t a t i o n f a c i l i t i e s . i i ) M o d i f y t h e b i o r e a c t o r s t o a c c o m m o d a t e t h e r e q u i r e d a n a e r o b i c , a n o x i c a n d a e r o b i c z o n e s . i i i ) P r o v i d e f a c i l i t i e s f o r t h e l i m e t r e a t m e n t o f t h e r e c y c l e s t r e a m s f r o m t h e a n a e r o b i c d i g e s t o r s . P C ' s (8) BIOREACTORS (8) ALUM S C ' s (8) I ! FERMENTERS (4) -_r1 I C l TREATED EFFLUENT DENOTES BIO-P MODIFICATION DIGESTORS (6) F I G U R E 4.8 - E D M O N T O N G O L D B A R R E T R O F I T F L O W S H E E T F I G U R E 4 . 9 - E D M O N T O N G O L D B A R R E T R O F I T L A Y O U T FERMENTER SUPERNATANT FROM P.C.'s t o o o o o O O 4 o a CM TO — • SC's 97.5 m O ~ MIXER CELL STATUS HRT (HRS.) 1,2 UNAERATED 0.5 3,4,5 UNAERATED/ 0.5 AERATED 6 AERATED 0.5 7,8 AERATED 1.0 F I G U R E 4 . 1 0 - E D M O N T O N G O L D B A R R E T R O F I T B I O R E A C T O R L A Y O U T - 1 4 8 -U n l i k e C a l g a r y B o n n y b r o o k , w h e r e t h e p r e s e n c e o f n i t r a t e s i n t h e i n f l u e n t d i c t a t e d t h e d e s i g n o f t h e f e r m e n t e r a n d t h e b i o r e a c t o r , t h e d e s i g n o f t h e G o l d B a r f a c i l i t i e s i n v o l v e d s o m e o p t i m i z a t i o n . T w o o p t i o n s w e r e c o n s i d e r e d . T h e f i r s t o p t i o n ( a s s h o w n i n F i g u r e 4 . 1 1 ) u s e s a g r a v i t y t h i c k e n e r f o r p r i m a r y s l u d g e f e r m e n t a t i o n i n c o n j u n c t i o n w i t h a n a n o x i c / a n a e r o b i c / a e r o b i c s e q u e n c e i n t h e b i o r e a c t o r . T h e s e c o n d o p t i o n i s i l l u s t r a t e d i n F i g u r e 4 . 1 1 a n d c o n s i s t s o f a c o m p l e t e l y m i x e d f e r m e n t e r i n c o n j u n c t i o n w i t h a n a n a e r o b i c / a n o x i c / a e r o b i c s e q u e n c e i n t h e b i o r e a c t o r . T h i s o p t i o n i s s i m i l a r t o t h e p r o c e s s u s e d i n t h e U B C p i l o t p l a n t . T h e s e o p t i o n s w e r e c o n s i d e r e d a s t h e y c a n b o t h b e o p e r a t e d d u r i n g n i t r i f y i n g a n d n o n - n i t r i f y i n g c o n d i t i o n s . E s t i m a t e s o f t h e c a p i t a l a n d o p e r a t i n g c o s t s a s s o c i a t e d w i t h b o t h o p t i o n s w e r e d e v e l o p e d a n d a r e p r e s e n t e d i n T a b l e 4 . 4 . A s s h o w n i n T a b l e 4 . 4 t h e g r a v i t y t h i c k e n e r , a n o x i c / a n a e r o b i c / a e r o b i c o p t i o n h a s l o w e r c a p i t a l a n d o p e r a t i n g c o s t s . T h e a n o x i c / a n a e r o b i c / a e r o b i c a l s o h a s e x c e l l e n t o p e r a t i n g f l e x i b i l i t y . D u r i n g w i n t e r c o n d i t i o n s , w h e n n i t r i f i c a t i o n d o e s n o t o c c u r , n i t r a t e s w i l l n o t b e p r e s e n t i n t h e r e t u r n s l u d g e a n d h e n c e t h e p l a n t w o u l d b e o p e r a t e d i n a n a n a e r o b i c / a e r o b i c m o d e . D u r i n g t h e s e c o n d i t i o n s , t h i c k e n e r s u p e r n a t a n t w o u l d b e a d d e d t o t h e h e a d o n t h e b i o r e a c t o r . W h e n n i t r i f i c a t i o n d o e s o c c u r , t h e - 1 4 9 -PRIMARY CLARIFIER ANOXIC ANAEROBIC SECONDARY CLARIFIER TO SLUDGE HANDLING PRIMARY CLARIFIER OPTION 1 - ANOXIC/ANAEROBIC/AEROBIC PROCESS WITH GRAVITY THICKENING ANAEROBIC ANOXIC AEROBIC RAS FERMENTER CO TO SLUDGE HANDLING OPTION 2 - UBC PILOT PLANT PROCESS SECONDARY CLARIFIER F I G U R E 4 . 1 1 - E D M O N T O N G O L D B A R P R O C E S S O P T I O N S ANOHIC/RNAEROBIC/AEROBIC PROCESS U / GRRVITV THICKENING UBC PILOT PLANT PROCESS 1 . CAPITAL COSTS DESCRIPTION TIC C » M 1 0 0 0 > DESCRIPTION TIC < S » 1 0 0 0 » A. FERMENTER B. TUNNEL 4 - 2 1 M DIAM H 3 . 5 H SUD THICKENERS U / U/G CONCRETE TANKS TOTAL EHCAVATION - 1 9 8 0 M 3 1 0 9 2 2 9 2 4 - 2 1 M DIAM M 3 . 5 M SUD U/G CONCRETE TANKS U / MINERS TOTAL EHCAVATION - I 9 6 0 M 3 4 6 2 2 9 2 C. SUPERNATANT PUMPS ft PIPING 2 - 1 0 0 L/«, 3 5 . 4 H TON 4 6 6 NOT REQUIRED 0 . RECVCLE PUflPS ft PIPING 2 - 1 0 0 L/., 10 H TDH 6 6 2 - 1 0 0 L/s, 1 0 H TDH 3 0 0 M , 3 0 0 MM D PIPING 1 8 7 E. WASTE SLUDGE PUMPS ft PIPING 2 - 1 0 0 L/s, 2 2 . 5 M TDH 8 0 2 - 1 0 0 L/s, 2 2 . 5 M TDH 6 0 F. MINED LIQUOR RECVCLE PUMPS ft PIPING NOT REQUIRED 1 6 - 2 4 6 L/s, 6 H TDH U / VARIABLE FREQUENCV CONTROLLERS 1 0 1 6 TOTAL 1 9 9 7 2 0 3 7 2 . OPERATING COSTS DESCRIPTION ANNUAL COST C S M I O O O ) f DESCRIPTION ANNUAL COST <*M1000> A. THICKENER RAKES 4 M 6 . 0 k U 3 4 0 0 NOT REQUIRED B. FERMENTER MINERS NOT REQUIRED 4 M 6 . 0 k U 3 4 0 0 C. SUPERNATANT PUMPS SO k U 7 0 0 0 NOT REQUIRED 0 . MINED LIQUOR RECVLE NOT REQUIRED D U M P * 6 M 2 0 . 7 k U 2 3 0 0 0 TOTAL 1 0 4 0 0 2 6 4 0 0 T A B L E 4.4 - E D M O N T O N G O L D B A R P R O C E S S O P T I O N E C O N O M I C S U M M A R Y - 1 5 1 -t h i c k e n e r s u p e r n a t a n t w o u l d b e a d d e d f u r t h e r a l o n g t h e r e a c t o r , s u c h t h a t c o m p l e t e d e n i t r i f i c a t i o n o f t h e n i t r a t e s i n t h e r e t u r n s l u d g e i s a c h i e v e d p r i o r t o t h e a d d i t i o n o f t h e s u p e r n a t a n t . T h e r e f o r e , b a s e d o n e c o n o m i c s a n d o p e r a t i n g f l e x i b i l i t y , t h e u s e o f g r a v i t y t h i c k e n i n g f o r p r i m a r y s l u d g e f e r m e n t a t i o n i n c o n j u n c t i o n w i t h a n a n o x i c / a n a e r o b i c / a e r o b i c s e q u e n c e i n t h e b i o r e a c t o r , w a s s e l e c t e d f o r t h e G o l d B a r p l a n t . A s s h o w n i n F i g u r e 4 . 9 , t h e f e r m e n t e r s w o u l d b e l o c a t e d n o r t h o f D i g e s t o r s 5 a n d 6 . T h e f e r m e n t e r s w o u l d b e c o n s t r u c t e d b e l o w g r a d e f o r i n s u l a t i o n p u r p o s e s , a n d w o u l d b e c o n n e c t e d t o t h e e x i s t i n g d i g e s t o r c o n t r o l b u i l d i n g w i t h a n e w t u n n e l . A l l p u m p s f o r t h e f e r m e n t e r o p e r a t i o n w o u l d b e l o c a t e d i n t h e n e w t u n n e l . A l l p i p i n g r u n s b e t w e e n t h e f e r m e n t e r s a n d t h e b i o r e a c t o r s a n d d i g e s t o r s w o u l d b e l o c a t e d i n t h e e x i s t i n g t u n n e l s . E x i s t i n g p r i m a r y c l a r i f i e r u n d e r f l o w p u m p c a p a c i t i e s w e r e f o u n d t o b e a d e q u a t e f o r t h e f e r e m e n t e r o p e r a t i o n . T h e G o l d B a r b i o r e a c t o r s a r e i d e a l l y s u i t e d f o r c o n v e r s i o n t o B i o - P r e m o v a l a s t h e y c a n b e o p e r a t e d u n d e r p l u g - f l o w c o n d i t i o n s . C o n v e r s i o n t o B i o - P r e m o v a l w o u l d i n v o l v e c o m p a r t m e n t a l i z i n g t h e f i r s t t w o p a s s e s o f e a c h r e a c t o r a n d i n s t a l l i n g m i x e r s i n t h e f i r s t f i v e c o m p a r t m e n t s t o a c c o m m o d a t e t h e a n a e r o b i c a n d a n o x i c z o n e s . T h e t h i c k e n e r s u p e r n a t a n t l i n e w o u l d b e r u n a l o n g t h e s i d e o f t h e f i r s t p a s s a n d w o u l d c o n t a i n v a l v e s s u c h t h a t t h e s u p e r n a t a n t c o u l d b e a d d e d t o a n y o f t h e - 1 5 2 -f i r s t f o u r c o m p a r t m e n t s . S h u t - o f f v a l v e s w o u l d b e i n s t a l l e d o n t h e e x i s t i n g a i r s u p p l y t a k e - o f f s t o t h e a n a e r o b i c a n d a n o x i c c o m p a r t m e n t s s u c h t h a t t h e c e l l s c o u l d b e s w i t c h e d b e t w e e n a e r a t e d a n d n o n - a e r a t e d c o n d i t i o n s . I n t h e p r e s e n t o p e r a t i o n , t h e r e i s n o w a y o f s h u t t i n g o f f t h e a i r s u p p l y t o a p o r t i o n o f t h e t a n k . O R P m o n i t o r i n g w o u l d a l s o b e p r o v i d e d i n a l l b i o r e a c t o r s . C h e c k s o n b o t h t h e s o l i d s a n d h y d r a u l i c l o a d i n g s o n t h e f i v e s e c o n d a r y c l a r i f i e r s o n t h e w e s t s i d e o f t h e p l a n t s h o w e d 2 t h a t t h e s o l i d s l o a d i n g f o r a B i o - P p l a n t w o u l d b e 1 2 4 k g / m - d 3 2 a n d t h a t t h e h y d r a u l i c l o a d i n g w o u l d b e 2 9 m / m - d a t a v e r a g e f l o w c o n d i t i o n s . S i n c e t h e s e e x c e e d t h e r e q u i r e m e n t s s p e c i f i e d i n S e c t i o n 3 . 3 . 6 , e x t e n s i o n s t o t h e s e c l a r i f i e r s w o u l d b e r e q u i r e d s h o u l d p h o s p h o r u s r e m o v a l b e i m p l e m e n t e d . H o w e v e r , e x t e n s i o n s w o u l d a l s o b e r e q u i r e d f o r c h e m i c a l p h o s p h o r u s r e m o v a l . T h e r e f o r e , i n c r e m e n t a l c o s t s w o u l d n o t b e r e a l i z e d . L o a d i n g s o n t h e o t h e r t h r e e c l a r i f i e r s w e r e w i t h i n t h e a c c e p t a b l e l i m i t s . R A S p u m p s w e r e a l s o f o u n d t o b e a d e q u a t e f o r B i o - P r e m o v a l . T h e o n l y m o d i f i c a t i o n s r e q u i r e d t o c o n v e r t t h e s l u d g e h a n d l i n g f a c i l i t i e s f o r B i o - P r e m o v a l w o u l d b e t h e d i v e r s i o n o f t h e d i g e s t o r o v e r f l o w t o t h e s l u d g e l a g o o n s a n d t h e i n s t a l l a t i o n o f f a c i l i t i e s f o r t h e l i m e t r e a t m e n t o f t h e l a g o o n s u p e r n a t a n t a t t h e l a g o o n s i t e . I t w a s c o n c l u d e d t h a t t h i s w a s t h e m o s t - 1 5 3 -e c o n o m i c a l a n d p r a c t i c a l m e t h o d o f h a n d l i n g t h e s l u d g e . T h e u s e o f d i s s o l v e d a i r f l o t a t i o n f o r WAS t h i c k e n i n g c o m b i n e d w i t h c o m p o s t i n g f o r s t a b i l i z a t i o n w a s c o n s i d e r e d b u t r e j e c t e d f o r t h e f o l l o w i n g r e a s o n s : i ) T h e c o s t o f d i s s o l v e d a i r f l o t a t i o n a p p e a r s t o b e p r o h i b i t i v e . T h e c o s t o f t h e m e c h a n i c a l c o m p o n e n t s a l o n e w o u l d b e $ 6 2 5 , 0 0 0 ( K i r k , 1 9 8 8 ) . A l l o w i n g f o r i n s t a l l a t i o n , u t i l i t y a n d p r o c e s s t i e - i n s , a n d c o n c r e t e t a n k s , i t i s e s t i m a t e d t h a t t h e T I C o f t h e D A F u n i t s w o u l d b e a p p r o x i m a t e l y $ 1 , 4 0 0 , 0 0 0 . A d d i t i o n a l c a p i t a l w o u l d b e r e q u i r e d t o s e t - u p c o m p o s t i n g f a c i l i t i e s . i i ) D i g e s t o r g a s p r o d u c t i o n w o u l d b e r e d u c e d b y 3 a p p r o x i m a t e l y 2 2 , 0 0 0 m / d b y n o t d i g e s t i n g t h e W A S . T h e a n n u a l c o s t o f " m a k i n g - u p " t h i s w i t h a n e q u i v a l e n t a m o u n t o f n a t u r a l g a s w o u l d b e a p p r o x i m a t e l y $ 5 7 1 , 0 0 0 . A d d i t i o n a l c o s t s w o u l d b e i n c u r r e d t o o p e r a t e t h e c o m p o s t i n g o p e r a t i o n . i i i ) T h e i m p l e m e n t a t i o n o f d i f f e r e n t s l u d g e h a n d l i n g o p e r a t i o n s w o u l d b e v e r y d i s r u p t i v e t o t h e e x i s t i n g o p e r a t i o n . F a c i l i t i e s f o r t h e l i m e t r e a t m e n t o f t h e l a g o o n s u p e r n a t a n t w e r e l o c a t e d a t t h e s l u d g e l a g o o n s s u c h t h a t t h e l i m e s l u d g e c o u l d b e d e w a t e r e d i n t h e l a g o o n s . A s n o t e d i n S e c t i o n 4 . 1 , t h e a d d i t i o n o f l i m e s h o u l d n o t c r e a t e a n y p r o b l e m s w i t h r e s p e c t t o l a n d a p p l i c a t i o n o f t h e d e w a t e r e d s l u d g e . - 1 5 4 -A c o m p a r i s o n o f t h e o p e r a t i n g p a r a m e t e r s f o r a B i o - P r e m o v a l f a c i l i t y v e r s u s a c h e m i c a l p h o s p h o r u s r e m o v a l f a c i l i t y i s p r e s e n t e d i n T a b l e 4 . 5 . A s s h o w n i n t h i s t a b l e , B i o - P r e m o v a l r e s u l t s i n r e d u c e d a l u m c o n s u m p t i o n , d i g e s t o r g a s p r o d u c t i o n , a n d o x y g e n d e m a n d u n d e r n i t r i f y i n g c o n d i t i o n s . I t s h o u l d b e n o t e d t h a t , o n t h e b a s i s o f a s s u m p t i o n s p r e v i o u s l y d i s c u s s e d , a s m a l l q u a n t i t y o f a l u m ( 1 0 m g / L ) w o u l d b e r e q u i r e d t o l o w e r s o l u b l e p h o s p h o r u s l e v e l s s u c h t h a t a n e f f l u e n t T P o f 1 . 0 m g / L c o u l d b e a c h i e v e d . T a b l e 4 . 5 a l s o i n d i c a t e s t h a t a B i o - P f a c i l i t y w o u l d c o n s u m e m o r e l i m e a n d e l e c t r i c i t y ; w o u l d r e q u i r e a d d i t i o n a l o p e r a t i o n s s t a f f ; a n d w o u l d p r o d u c e m o r e s l u d g e t h a n a c h e m i c a l r e m o v a l f a c i l i t y . T h e r e q u i r e m e n t f o r l i m e t r e a t m e n t o f t h e l a g o o n s u p e r n a t a n t i s r e s p o n s i b l e f o r t h e i n c r e a s e d s l u d g e p r o d u c t i o n . I t w a s a s s u m e d t h a t o n e a d d i t i o n a l f u l l - t i m e o p e r a t o r w o u l d b e r e q u i r e d t o o p e r a t e t h e l i m e t r e a t m e n t f a c i l i t y a n d t h a t a n o t h e r f u l l - t i m e p o s i t i o n w o u l d b e r e q u i r e d f o r t h e i n c r e a s e d l a b o r a t o r y a n a l y s e s a n d t h e o p e r a t i o n a n d m a i n t e n a n c e o f t h e f e r m e n t e r . - 1 5 5 -P A R A M E T E R A l u m C o n s u m p t i o n ( k g / d ) B I O - P C A S E 3 , 4 4 1 C H E M I C A L P  C A S E 3 6 , 2 2 0 L i m e C o n s u m p t i o n ( k g / d ) 9 , 2 5 5 S l u d g e P r o d u c t i o n - M a s s ( k g / d ) 3 - V o l u m e (m / d ) 5 7 , 5 7 6 5 2 3 5 4 , 9 0 9 4 9 9 O x y g e n D e m a n d ( k g / d ) w / o N i t r i f i c a t i o n - w / N i t r i f i c a t i o n 3 5 , 6 2 4 6 5 , 4 5 3 3 2 , 5 3 1 6 9 , 8 2 2 M e t h a n e P r o d u c t i o n (m / d ) 3 6 , 2 7 6 3 8 , 5 4 7 I n c r e m e n t a l P o w e r C o n s u m p t i o n (kw) 1 . +92 I n c r e m e n t a l O p e r a t i o n s S t a f f +2 T A B L E 4.5 - E D M O N T O N G O L D B A R O P E R A T I O N S C O M P A R I S O N 2 . I n c l u d e s p o w e r s a v i n g s f r o m r e d u c e d o x y g e n d e m a n d . B a s e d o n a n i n f l u e n t f l o w o f 3 4 0 , 0 0 0 m / d . - 1 5 6 -4 . 2 . 3 C o s t A n a l y s i s A s u m m a r y o f t h e i n c r e m e n t a l c a p i t a l c o s t s a s s o c i a t e d w i t h B i o - P r e m o v a l i s p r e s e n t e d i n T a b l e 4 . 6 . A s s h o w n , t h e t o t a l i n c r e m e n t a l c a p i t a l c o s t f o r t h e B i o - P r e t r o f i t i s a p p r o x i m a t e l y $ 4 , 2 6 1 , 0 0 0 . A s u m m a r y o f t h e i n c r e m e n t a l o p e r a t i n g c o s t s f o r B i o - P r e m o v a l i s p r e s e n t e d i n T a b l e 4 . 7 . A s i n d i c a t e d , t h e u s e o f B i o - P r e m o v a l w i l l r e s u l t i n a n a n n u a l s a v i n g s o f a p p r o x i m a t e l y $ 2 , 0 0 2 , 0 0 0 o v e r a n e q u i v a l e n t c h e m i c a l p h o s p h o r u s r e m o v a l s y s t e m . T h i s s a v i n g s i s a l m o s t e n t i r e l y a t t r i b u t a b l e t o l a r g e r e d u c t i o n s i n a l u m c o n s u m p t i o n . B a s e d o n t h e s e e s t i m a t e s , t h e s i m p l e p a y b a c k p e r i o d f o r t h e c a p i t a l i n v e s t m e n t i s 2 . 1 y e a r s . I R R ' s f o r t h e i n v e s t m e n t f o r v a r i o u s p r o j e c t l i v e s a r e a s f o l l o w s : P R O J E C T L I F E f y e a r S t I R R (%) 5 4 1 . 0 1 0 4 6 . 5 1 5 4 6 . 9 2 0 4 7 . 0 TOTAL MATERIAL BULK INSTALLED NODIFICATION I TEH SPECIFICATION OUANTITV COST INSTALLATION FACTOR COST C*> MANHOURS <#> VFA SUPPLV 1. 2. FERMENTER MECHANICAL FERMENTER TANK 2. BIOREACTOR 9. SUPERNATANT PUMPS 4. SUPERNATANT PIPING 5. SUPNT PUMP INSTN 6. RECVCLE PUMPS 7. RECVCLE INSTN 9. WASTE PUMPS 10. UASTE PUMP INSTN 11. TUNNEL EXPANSION 1. COHPARTHENTAH ZATION 2. ORP PROBES 9. ORP RECORDERS 4. MIXERS 5. AIR PIPINO VALUES 21.0 M DIAH, 9.5 H SUD, 4.0 kU CONCRETE EXCAVATION 100 L/s, 35.4 M TOH, 50 kU 100 N H ASTM A59 150 MM ASTM A59 AS PER FIGURE 9.2 100 L/s, 15.0 AS PER FIGURE 100 L/s, 22.5 AS PER FIGURE 9.2 EXCAVATION CONCRETE 9. LIME TREATMENT OF DIGESTOR SUPERNATANT TDH, 21 kU 9.2 TOH, 91.5 kU 1. STORAGE SILOS 2. CHEMICAL FEEDER 9. MIX TANK 4. MIX TANK MIXER 5. HOLDING TANK FD PUMPS 6. HOLDING TANK 7. HOLDINO TANK MIXER 8. HOLDING TANK PUMPS 10. RAPID MIX/FLOCCN TNK 11. RAPID MIX MIXER 12. FLOCCN MIXER 19.CLARIFIER MECHANICAL 14. CLARIFIER TANK 15. LI HE SLUDOE PUHPS 16. BUILDING CONRETE PARTITIONS 2.4 kU, 1640 rpn 100 MM GATE VALVES • FLANGES STEEL U/ EPOXV LINER, 196 N9 ROTARV TVPE, 7T1 kg/hr STEEL, 9.2 H9 1.2 kU 11 L/s, 6.0 M TDH, 1.0 kU 90B «9 I. 2 kW 9^ 1 L/s, 9.0 M TDH, 0.20kU IT.9 »9 0.79 kU 0.07 kU II. 6 m DIAM, 9.0 M SUD, 2.5 kU CONCRETE EXCAVATION 5.0 L/s, 10.0 n TDH, 0.70 kU 90 H « 25 H « 6M 4 992000 1.84 750131 967 M9 106425 3677 224654 7629 M9 1S25 47263 2 26000 3.8 102752 BOO H 83280 9576 197467 580 M 76154 2601 166044 1 6900 52 8788 2 13070 9.8 51653 1 6900 52 8788 2 17400 9.8 66765 1 6900 52 8788 I960 H 9 396 12276 429 H9 116325 4124 248830 224 N9 61600 2128 130032 16 16OO0 2.1 34944 6 2800 2. 1 6115 80 280000 1.34 390208 256 115725 3507 229071 9 109620 2.4 273612 9 54O00 1.23 69077 1 7680 5.7 45527 1 2000 1.34 2787 . 3764 3.8 14875 1 58000 2.2 132704 1 2000 1.34 2787 1882 9.8 7498 1 12590 4 52125 1 1691 1.94 2357 1 904 1.34 1260 1 69625 1.84 133294 66 18150 627 2.5 98319 999 78 2412 2 4980 3.8 17910 750 H2 922500 SUB—TOTAL 9804884 ENGINEERING 456586 TOTAL 4261470 T A B L E 4.6 - E D M O N T O N G O L D B A R C A P I T A L C O S T S U M M A R Y - 1 5 8 -I T E M I N C R E M E N T A L A N N U A L C O S T 1 . A l u m 2 . L i m e 3 . N a t u r a l G a s 4 . S l u d g e D i s p o s a l 5 . P o w e r 6 . O p e r a t i o n s S t a f f 7 . M a i n t e n a n c e M a t e r i a l s T O T A L ( $ 2 , 5 7 2 , 0 0 0 ) 3 6 1 , 0 0 0 6 0 , 0 0 0 2 3 , 0 0 0 1 3 , 0 0 0 9 4 , 0 0 0 1 9 , 0 0 0 ( $ 2 , 0 0 2 , 0 0 0 ) T A B L E 4 . 7 - E D M O N T O N G O L D B A R O P E R A T I N G C O S T S U M M A R Y - 1 5 9 -4 . 3 R e g i n a S e w a g e T r e a t m e n t P l a n t 4 . 3 . 1 P l a n t D e s c r i p t i o n T h e R e g i n a S e w a g e T r e a t m e n t P l a n t p r o v i d e s w a s t e w a t e r t r e a t m e n t f o r t h e e n t i r e C i t y o f R e g i n a . T h e p l a n t c u r r e n t l y s e r v e s a p o p u l a t i o n o f 1 6 3 , 0 0 0 a n d h a s a d e s i g n c a p a c i t y o f 9 0 , 9 1 9 m 3 / d . T h e p l a n t p r e s e n t l y p r o v i d e s p r i m a r y t r e a t m e n t , s e c o n d a r y t r e a t m e n t i n t h e f o r m o f a e r a t e d l a g o o n s , a n d t e r t i a r y t r e a t m e n t t h r o u g h a l u m a d d i t i o n t o t h e s e c o n d a r y e f f l u e n t . T r e a t e d e f f l u e n t i s d i s p o s e d t o W a s c a n a C r e e k . P r i m a r y s l u d g e i s a n a e r o b i c a l l y d i g e s t e d i n t w o - s t a g e a n a e r o b i c d i g e s t o r s , d e w a t e r e d b y b e l t f i l t e r p r e s s e s t o 3 5 p e r c e n t s o l i d s , a n d t h e n d i s p e n s e d o f t o a l a n d f i l l . T e r t i a r y s l u d g e i s s t o r e d i n a n o n s i t e s l u d g e s t o r a g e c e l l . S l u d g e f r o m t h i s c e l l i s p e r i o d i c a l l y r e m o v e d a n d s t o c k p i l e d o n s i t e . A l a y o u t d r a w i n g o f t h e p l a n t i s p r e s e n t e d i n F i g u r e 4 . 1 2 . T h e c u r r e n t p e r m i t t o o p e r a t e f r o m S a s k a t c h e w a n E n v i r o n m e n t p l a c e s r e s t r i c t i o n s o n T P ( < 1 . 0 m g / L ) , p h y t o p l a n k t o n c o n c e n t r a t i o n s , p H a n d f e c a l c o l i f o r m s f o r e f f l u e n t d i s c h a r g e s . - 1 6 1 -B e c a u s e w a s t e w a t e r f l o w s a r e c l o s e t o t h e d e s i g n c a p a c i t y o f t h e p l a n t a n d m o r e s t r i n g e n t e f f l u e n t c r i t e r i a f o r d i s c h a r g e s t o W a s c a n a C r e e k a r e a n t i c i p a t e d , a n e x p a n s i o n o f t h e p l a n t i n t h e e a r l y 1 9 9 0 ' s i s r e q u i r e d . I t i s t h i s e x p a n s i o n w h i c h w i l l b e s t u d i e d w i t h r e s p e c t t o t h e f e a s i b i l i t y o f B i o - P r e m o v a l . O n t h e b a s i s o f a d r a f t c o p y o f t h e S e w a g e T r e a t m e n t P l a n t E x p a n s i o n S t u d y ( S t a n l e y A s s o c i a t e s , 1 9 8 6 A ) , t h e f o l l o w i n g a s s u m p t i o n s w e r e m a d e r e g a r d i n g t h e e x p a n s i o n : i ) T h e p l a n t w i l l b e c o n s t r u c t e d i n t w o p h a s e s . T h e f i r s t p h a s e w i l l b e c o m p l e t e d i n t h e y e a r 1 9 9 0 a n d w i l l 3 r e s u l t i n a p l a n t d e s i g n c a p a c i t y o f 1 1 4 , 0 0 0 m / d . T h e s e c o n d p h a s e w i l l b e c o m p l e t e d i n t h e y e a r 2 0 0 0 a n d w i l l r e s u l t i n a n i n c r e a s e d p l a n t d e s i g n c a p a c i t y o f 1 3 0 , 0 0 0 m 3 / d . i i ) E f f l u e n t s t a n d a r d s w i l l a l s o b e p h a s e d i n a c c o r d a n c e w i t h t h e f o l l o w i n g s c h e d u l e : 1 9 9 0 - 1 9 9 5 : B O D 5 - 2 0 m g / L T S S - 2 5 m g / L T P - 1 . 0 m g / L N H 3 - 2 5 m g / L - 1 6 2 -1 9 9 5 - 2 0 0 0 : B O D - 12 m g / L T S S - 1 5 m g / L T P - 1 . 0 m g / L N H 3 - 5 . 0 m g / L 2 0 0 0 - 2 0 1 0 : B O D , . - 8 . 5 m g / L T S S - 1 0 . 0 m g / L T P - 1 . 0 m g / L N H 3 - 5 . 0 m g / L S t a n l e y A s s o c i a t e s ( 1 9 8 6 A ) h a v e p r o p o s e d b i o l o g i c a l n i t r o g e n a n d p h o s p h o r u s r e m o v a l i n a n a c t i v a t e d s l u d g e p r o c e s s a s a n a l t e r n a t i v e f o r t h e p l a n t e x p a n s i o n b u t d i d n o t c o n s i d e r c h e m i c a l p h o s p h o r u s r e m o v a l i n c o n j u n c t i o n w i t h a n i t r i f y i n g a c t i v a t e d s l u d g e p r o c e s s . T h e p u r p o s e o f t h i s s t u d y i s t h e r e f o r e t o c o m p a r e t h e s e t w o a l t e r n a t i v e s . W a s t e w a t e r c h a r a c t e r i s t i c s u s e d f o r t h i s c o m p a r i s o n w e r e b a s e d o n t h o s e p r e s e n t e d b y S t a n l e y A s s o c i a t e s . T h e s e a r e a s f o l l o w s : 2 3 8 m g / L T S S 2 8 0 m g / L T P 7 . 7 m g / L - 1 6 3 -O t h e r c h a r a c t e r i s t i c s w e r e b a s e d o n 1 9 8 5 / 8 6 m o n t h l y a v e r a g e s a n d a r e l i s t e d a s f o l l o w s : T K N - 3 0 m g / L T m a x - 1 7 ° C T m i n - 1 0 ° C 4 . 3 . 2 R e t r o f i t M o d i f i c a t i o n s I n d e v e l o p i n g t h e i n c r e m e n t a l c a p i t a l a n d o p e r a t i n g c o s t s f o r a B i o - P r e m o v a l p l a n t c o m p a r e d t o a c h e m i c a l p h o s p h o r u s r e m o v a l p l a n t , t h e g e n e r a l p r o c e s s c o n f i g u r a t i o n a n d p l a n t l a y o u t p r o p o s e d b y S t a n l e y A s s o c i a t e s f o r a B i o - P p l a n t w a s a s s u m e d . T h e c o n s u l t a n t s p r o p o s e t o u t i l i z e t h e e x i s t i n g g r i t c h a m b e r s , p r i m a r y c l a r i f i e r s , d i g e s t o r s a n d f i l t e r p r e s s e s . F o r t h e f i r s t s t a g e e x p a n s i o n , o n e a d d i t i o n a l g r i t c h a m b e r , p r i m a r y c l a r i f i e r , d i g e s t o r a n d f i l t e r p r e s s w o u l d b e i n s t a l l e d a l o n g w i t h n e w a e r a t i o n t a n k s , s e c o n d a r y c l a r i f i e r s , g r a v i t y t h i c k e n e r s , s l u d g e c e n t r i f u g e s a n d a c h l o r i n e c o n t a c t c h a m b e r . D e w a t e r e d s l u d g e w o u l d b e s p r e a d o n a g r i c u l t u r a l l a n d . F o r t h e s e c o n d p h a s e e x p a n s i o n , o n e a d d i t i o n a l p r i m a r y c l a r i f e r , s e c o n d a r y c l a r i f i e r , d i g e s t o r a n d f i l t e r p r e s s w o u l d b e i n s t a l l e d . T h e b i o r e a c t o r s w o u l d b e e x t e n d e d a n d n e w e f f l u e n t f i l t e r s w o u l d b e p r o v i d e d . D e w a t e r e d s l u d g e w o u l d c o n t i n u e t o b e s p r e a d o n a g r i c u l t u r a l l a n d . - 1 6 4 -I n a d d i t i o n t o S t a n l e y A s s o c i a t e s ' p r o p o s e d p r o c e s s , l i m e t r e a t m e n t o f t h e d i g e s t o r s u p e r n a t a n t a n d f i l t e r p r e s s f i l t r a t e w o u l d b e r e q u i r e d t o p r e c i p i t a t e p h o s p h o r u s r e l e a s e d u n d e r a n a e r o b i c c o n d i t i o n s . C o n s i d e r a t i o n w a s g i v e n t o b y - p a s s i n g t h e WAS a r o u n d t h e d i g e s t o r t o t h e f i l t e r p r e s s e s . T h i s w o u l d n e g a t e p h o s p h o r u s r e l e a s e b u t w o u l d e l i m i n a t e t h e p o s s i b i l i t y f o r l a n d a p p l i c a t i o n o f t h e s l u d g e a s d r a f t d i s p o s a l g u i d e l i n e s i n S a s k a t c h e w a n n o t e t h a t s l u d g e s m u s t b e s t a b i l i z e d p r i o r t o b e i n g a p p l i e d t o a g r i c u l t u r a l l a n d ( S t a n l e y A s s o c i a t e s , 1 9 8 6 A ) . C o n s i d e r a t i o n w a s a l s o g i v e n t o b y - p a s s i n g t h e WAS a r o u n d t h e d i g e s t o r s c o m b i n e d w i t h t h e c o n t i n u e d d i s p o s a l o f s l u d g e t o s a n i t a r y l a n d f i l l s . H o w e v e r , t h e i n c r e a s e d s l u d g e p r o d u c t i o n a s s o c i a t e d w i t h t h e s e c o n d a r y p r o c e s s w o u l d l i k e l y s t r e s s t h e c a p a c i t y o f a v a i l a b l e l a n d f i l l s i t e s ( S t a n l e y A s s o c i a t e s , 1 9 8 6 A ) . T h e r e f o r e , i t w a s c o n c l u d e d t h a t a n a e r o b i c d i g e s t i o n o f WAS f o l l o w e d b y l i m e t r e a t m e n t o f t h e d i g e s t o r s u p e r n a t a n t a n d t h e f i l t e r p r e s s f i l t r a t e , w a s t h e b e s t m e t h o d o f h a n d l i n g t h e W A S . L a y o u t d r a w i n g s a n d f l o w s h e e t s f o r t h e p r o p o s e d B i o - P p l a n t a r e p r e s e n t e d i n F i g u r e s 4 . 1 3 a n d 4 . 1 4 . I t w a s n o t e d d u r i n g t h e v i s i t t o t h e p l a n t , t h a t l i m e a d d i t i o n f a c i l i t i e s a r e p r e s e n t i n t h e c h e m i c a l a d d i t i o n b u i l d i n g . T h e s e f a c i l i t i e s w e r e o r i g i n a l l y i n s t a l l e d f o r t e r t i a r y p h o s p h o r u s r e m o v a l b u t , d u e t o m e c h a n i c a l p r o b l e m s , w e r e r e p l a c e d w i t h t h e a l u m s y s t e m . T h e f a c i l i t i e s a r e d e s i g n e d t o INFLUENT GRIT TANKS (3) P C ' s (5) V THICKENERS (2) BIOREACTORS (3) CENTRIFUGES (4) HEAD OF / • • PLANT \ / CI V w / / TREATED EFFLUENT EFFLUENT FILTERS (4) • - DENOTES BIO-P MODIFICATION LIME .1. LAND APPLN PRIHARY DIGESTORS SECONDARY DIGESTORS FILTER PRESSES (4) F I G U R E 4 . 1 3 - R E G I N A R E T R O F I T F L O W S H E E T CENTRIFUGES BIOREACTOR BIOREACTOR BIOREACTOR NOT TO SCALE INFLUENT F I G U R E 4 . 1 4 - R E G I N A R E T R O F I T L A Y O U T - 1 6 7 -h a n d l e 4 3 , 6 3 6 k g / d o f l i m e a n d h e n c e , w o u l d b e m o r e t h a n a d e q u a t e f o r i n c o r p o r a t i o n i n t o a B i o - P p r o c e s s . T h e C i t y i s p r e s e n t l y s t u d y i n g o p t i o n s f o r r e p a i r i n g t h e s y s t e m . S i n c e t h e r e m e d i a l m e a s u r e s h a v e n o t y e t b e e n d e f i n e d , t h e u s e o f t h e s e f a c i l i t i e s w i l l n o t b e i n c l u d e d i n t h i s a n a l y s i s . H o w e v e r , s h o u l d t h e f a c i l i t i e s b e c o m e o p e r a b l e , t h e i r u s e w o u l d r e s u l t i n c o n s i d e r a b l e c a p i t a l c o s t s a v i n g s f o r a B i o - P p r o c e s s . B i o r e a c t o r c o n f i g u r a t i o n s d i f f e r e n t f r o m t h o s e p r o p o s e d b y S t a n l e y A s s o c i a t e s w e r e s e l e c t e d . T h e y p r o p o s e d a n A / 0 p r o c e s s f o r t h e f i r s t p h a s e a n d a B a r d e n p h o p r o c e s s f o r t h e s e c o n d p h a s e . T h i s s t u d y i s b a s e d o n t h e u s e o f a n o x i c / a n a e r o b i c / a e r o b i c p r o c e s s e s f o r b o t h p h a s e s . B i o r e a c t o r l a y o u t d r a w i n g s a r e p r e s e n t e d i n F i g u r e 4 . 1 5 . D u r i n g P h a s e I , t h e b i o r e a c t o r w o u l d o p e r a t e a t a 6 . 5 d a y S R T a n d , a s a r e s u l t , s o m e n i t r i f i c a t i o n w o u l d a l m o s t a s s u r e d l y o c c u r d u r i n g t h e s u m m e r . T h e r e f o r e , t h e a b i l i t y t o d e n i t r i f y t h e R A S w o u l d b e r e q u i r e d . H o w e v e r , s i n c e y e a r - r o u n d n i t r i f i c a t i o n i s n o t r e q u i r e d , a t o t a l n o m i n a l H R T o f o n l y 6 h o u r s w o u l d b e r e q u i r e d . D u r i n g P h a s e 2 , t h e b i o r e a c t o r w o u l d o p e r a t e a t S R T ' s u p t o 2 5 d a y s t o e n s u r e y e a r - r o u n d n i t r i f i e r g r o w t h , a n d w i l l a l s o r e q u i r e a l o n g e r H R T (9 h o u r s ) t o a c c o m m o d a t e t h e r e d u c e d n i t r i f i c a t i o n r a t e s i n t h e w i n t e r . 6 * 7 . 5 m - 45 m FROM PC's TO SC's FERMENTER SUPERNATANT 2 o 12 i o o o \> o O i i O - MIXER r 10 CELL STATUS 1.2 3-6 7-12 UNAERATED AERATED/ UNAERATED AERATED HRT (HRS) 0.5 0.5 1.0 F I G U R E 4 . 1 5 - R E G I N A R E T R O F I T B I O R E A C T O R L A Y O U T [5313 - 1 6 9 -T h e a n o x i c / a n a e r o b i c / a e r o b i c p r o c e s s w a s s e l e c t e d b e c a u s e i t b e s t s u i t s t h e n u t r i e n t r e m o v a l r e q u i r e m e n t s a n d m i n i m i z e s c a p i t a l c o s t s . B e c a u s e i t i s d e s i g n e d t o r e m o v e NH^ a n d p h o s p h o r u s o n l y , d e n i t r i f i c a t i o n o f t h e R A S i s r e q u i r e d . I n c o m p a r i s o n , f o r t h e B a r d e n p h o p r o c e s s t o a c h i e v e g o o d p h o s p h o r u s r e m o v a l , c o m p l e t e d e n i t r i f i c a t i o n i s r e q u i r e d . T h i s n e c e s s i t a t e s l a r g e r e a c t o r s h a v i n g H R T ' s o f u p t o 2 0 h o u r s . I n a d d i t i o n , m i x e d l i q u o r r e c y c l e p u m p s , w h i c h a r e n o t a p a r t o f t h e a n o x i c / a n a e r o b i c / a e r o b i c p r o c e s s , a r e r e q u i r e d i n t h e B a r d e n p h o p r o c e s s . T h e o p e r a t i o n o f t h e t h i c k e n e r s i n t h i s s t u d y , a l s o d i f f e r s f r o m t h a t p r o p o s e d b y S t a n l e y A s s o c i a t e s . I n t h i s s t u d y , t h e t h i c k e n e r s w i l l b e u s e d f o r p r i m a r y s l u d g e f e r m e n t a t i o n i n a d d i t i o n t o s l u d g e t h i c k e n i n g . T h i s w o u l d r e q u i r e t h e a d d i t i o n o f u n d e r f l o w r e c y c l e p u m p s a n d t h e r o u t i n g o f t h e t h i c k e n e r s u p e r n a t a n t t o t h e a n a e r o b i c z o n e o f t h e b i o r e a c t o r . P u m p s w o u l d b e r e q u i r e d t o t r a n s f e r t h e s u p e r n a t a n t t o t h e b i o r e a c t o r . A f l o w s h e e t f o r a c o m p a r a b l e c h e m i c a l p h o s p h o r u s r e m o v a l p r o c e s s i s p r e s e n t e d i n F i g u r e 4 . 1 6 . A s s u m p t i o n s r e g a r d i n g t h e c h e m i c a l p h o s p h o r u s r e m o v a l p r o c e s s a r e a s f o l l o w s : i ) B o t h p r i m a r y ( g r a v i t y t h i c k e n e r s ) a n d s e c o n d a r y ( c e n t r i f u g e s ) s l u d g e t h i c k e n i n g w o u l d b e r e q u i r e d t o m i n i m i z e v o l u m e t r i c l o a d i n g s o n t h e d i g e s t o r s . P C ' s (4) INFLUENT GRIT TANKS (3) TO HEAD OF PLANT THICKENERS (2) BIOREACTORS (3) CENTRIFUGES (4) PRIMARY DIGESTORS ALUM CI V (4) / r ' EFFLUENT FILTERS (4) HEAD OF PLANT SECONDARY DIGESTORS FILTER PRESSES (4) TREATED EFFLUENT LAND APPLN o F I G U R E 4 . 1 6 - R E G I N A C H E M I C A L P H O S P H O R U S R E M O V A L F L O W S H E E T - 1 7 1 -i i ) P l u g f l o w a e r a t i o n t a n k s u s i n g d i f f u s e d a i r a e r a t i o n w o u l d b e e m p l o y e d . i i i ) A u t o m a t i c DO c o n t r o l w o u l d b e p r o v i d e d . i v ) A l u m w o u l d b e u s e d f o r p h o s p h o r u s r e m o v a l . D i f f e r e n c e s b e t w e e n t h e B i o - P a n d c h e m i c a l r e m o v a l p r o c e s s e s a r e t h e r e f o r e a s f o l l o w s : i ) T h e g r a v i t y t h i c k e n e r s f o r t h e B i o - P p r o c e s s w o u l d b e c o n s i d e r a b l y l a r g e r t h a n t h o s e r e q u i r e d f o r t h e c h e m i c a l r e m o v a l p r o c e s s ( 2 - 2 0 m d i a m e t e r u n i t s v e r s u s 2 - 1 0 . 8 m u n i t s ) s i n c e t h e y s h o u l d b e s i z e d t o p r o v i d e a n 8 h o u r HRT a t a p r i m a r y c l a r i f i e r u n d e r f l o w r a t e o f 5 p e r c e n t o f t h e p l a n t i n f l o w . i i ) T h i c k e n e r u n d e r f l o w r e c y c l e p u m p s a n d p i p i n g w o u l d b e r e q u i r e d f o r t h e B i o - P p r o c e s s b u t n o t f o r t h e c h e m i c a l r e m o v a l p r o c e s s . i i i ) T h i c k e n e r s u p e r n a t a n t p u m p s w o u l d b e r e q u i r e d f o r t h e B i o - P p r o c e s s b u t n o t f o r t h e c h e m i c a l r e m o v a l p r o c e s s . A d d i t i o n a l s u p e r n a t a n t p i p i n g w o u l d a l s o b e r e q u i r e d f o r t h e B i o - P p r o c e s s s i n c e t h e s u p e r n a t a n t m u s t b e r o u t e d t o t h e b i o r e a c t o r s . - 1 7 2 -i v ) T h e b u i l d i n g h o u s i n g t h e t h i c k e n e r s w o u l d b e l a r g e r f o r t h e B i o - P p r o c e s s . v ) T h e a e r a t i o n b a s i n s f o r t h e B i o - P p r o c e s s w o u l d b e c o m p a r t m e n t a l i z e d . M i x e r s w o u l d b e i n s t a l l e d i n t h e p o t e n t i a l l y n o n - a e r a t e d z o n e s . v i ) O R P m o n i t o r i n g w o u l d b e r e q u i r e d i n t h e a n a e r o b i c a n d a n o x i c z o n e s o f t h e B i o - P p r o c e s s . v i i ) L i m e t r e a t m e n t f a c i l i t i e s f o r t h e c o m b i n e d t r e a t m e n t o f t h e d i g e s t o r s u p e r n a t a n t a n d t h e f i l t e r p r e s s f i l t r a t e w o u l d b e r e q u i r e d f o r t h e B i o - P p r o c e s s . v i i i ) O n e a d d i t i o n a l o p e r a t i n g s t a f f m e m b e r w o u l d b e r e q u i r e d f o r a B i o - P p l a n t t o a s s i s t w i t h t h e l i m e t r e a t m e n t f a c i l i t y o p e r a t i o n , O R P p r o b e c l e a n i n g , t h e f e r m e n t e r o p e r a t i o n a n d a d d i t i o n a l l a b o r a t o r y a n a l y s i s . A c o m p a r i s o n o f t h e o p e r a t i n g p a r a m e t e r s b e t w e e n B i o - P a n d c h e m i c a l r e m o v a l p r o c e s s e s i s s h o w n i n T a b l e 4 . 8 . P a r a m e t e r s a r e p r e s e n t e d f o r t h r e e s e p a r a t e t i m e i n t e r v a l s ( 1 9 9 0 - 1 9 9 5 , 1 9 9 5 - 2 0 0 0 , 2 0 0 0 - 2 0 1 0 ) t o r e f l e c t t h e c h a n g e s i n e f f l u e n t s t a n d a r d s a n d f l o w r a t e s . - 1 7 3 -A s s h o w n i n T a b l e 4 . 8 , B i o - P r e m o v a l w o u l d r e s u l t i n r e d u c e d a l u m c o n s u m p t i o n , o x y g e n d e m a n d a n d d i g e s t o r g a s p r o d u c t i o n . S m a l l a m o u n t s o f a l u m ( 1 0 t o 1 5 m g / L ) w o u l d b e r e q u i r e d f o r t h e B i o - P p r o c e s s t o r e d u c e s o l u b l e p h o s p h o r u s c o n c e n t r a t i o n s i n o r d e r t o a c h i e v e t h e d e s i r e d e f f l u e n t T P c o n c e n t r a t i o n . B i o - P r e m o v a l w o u l d a l s o r e s u l t i n i n c r e a s e d l i m e a n d p o w e r c o n s u m p t i o n , a n d i n c r e a s e d s l u d g e p r o d u c t i o n . I n c r e a s e d s l u d g e p r o d u c t i o n r e s u l t s f r o m t h e l i m e t r e a t m e n t o f t h e h i g h l y a l k a l i n e d i g e s t o r s u p e r n a t a n t . I n c r e a s e d p o w e r c o n s u m p t i o n i s a s s o c i a t e d w i t h t h e f e r m e n t e r a n d l i m e t r e a t m e n t o p e r a t i o n s , a n d t h e n o n - a e r a t e d z o n e m i x e r s . 4 . 3 . 3 C o s t A n a l y s i s A s u m m a r y o f t h e i n c r e m e n t a l c a p i t a l c o s t s a s s o c i a t e d w i t h B i o - P r e m o v a l i s p r e s e n t e d i n T a b l e 4 . 9 . A s s h o w n , t h e t o t a l i n c r e m e n t a l c a p i t a l c o s t i s $ 2 , 1 3 2 , 0 0 0 . I t s h o u l d b e n o t e d t h a t t h e c o s t s s h o w n f o r t h e t h i c k e n e r s a n d t h e i r a s s o c i a t e d t a n k s , r e p r e s e n t t h e d i f f e r e n c e b e t w e e n t h e c o s t s o f t h i c k e n e r s f o r B i o - P a n d c h e m i c a l r e m o v a l p r o c e s s e s . A s u m m a r y o f t h e i n c r e m e n t a l o p e r a t i n g c o s t s f o r 1 9 9 0 -1 9 9 5 , 1 9 9 5 - 2 0 0 0 a n d 2 0 0 0 - 2 0 1 0 i s p r e s e n t e d i n T a b l e 4 . 1 0 . A n n u a l s a v i n g s o f $ 2 9 7 , 0 0 0 , $ 2 8 3 , 0 0 0 a n d $ 3 2 3 , 0 0 0 w o u l d b e r e a l i z e d f o r t h e s e t h r e e p e r i o d s r e s p e c t i v e l y . 1 9 9 0 ~ 1 9 9 5 1 9 9 5 - 2 0 0 0 2 0 0 0 - 2 0 1 0 1 . 2 . 3 . 4 . 5 . 6 . 7 . P A R A M E T E R A l u m C o n s u m p t i o n ( k g / d ) L i m e C o n s u m p t i o n ( k g / d ) S l u d g e P r o d u c t i o n 1 - M a s s ( k g / d ) - V o l u m e (m / d ) D i g e s t o r G a s P r o d u c t i o n ( n /<*) O x y g e n D e m a n d ( k g / d ) I n c r e m e n t a l P o w e r C o n s u m p t i o n (kw) I n c r e m e n t a l O p e r a t i o n s S t a f f B I O - P 1 1 4 2 3 1 9 7 1 7 0 2 3 5 7 1 0 4 0 4 1 0 8 6 1 2 + 4 6 + 1 C H E M I C A L R E M O V A L 8 2 6 4 1 6 2 6 4 5 1 1 1 1 3 5 9 9 1 1 2 B I O - P 1 7 0 9 2 8 6 1 1 5 3 8 0 5 1 9 1 2 3 2 2 9 5 0 + 4 6 + 1 C H E M I C A L R E M O V A L 8 2 6 4 1 4 6 9 8 4 9 1 0 2 4 5 2 3 2 6 9 B I O - P 1 9 4 9 3 2 6 3 1 7 5 3 9 58 9 8 7 9 2 6 1 7 1 +53 +1 C H E M I C A L R E M O V A L 9 5 1 0 1 6 7 6 2 5 6 1 1 6 8 4 2 6 5 3 5 T A B L E 4 .8 - R E G I N A O P E R A T I O N S C O M P A R I S O N N o t e s ; 1 . D e w a t e r e d s l u d g e . 2 . A s s u m e s n o n i t r i f i c a t i o n . TOTAL MODIFICATION ITEM SPECIFICATION MATERIAL BULK INSTALLED 1UANTITV COST INSTALLATION FACTOR COST <»> MANHOURS <*> 2 58766 1.84 120326 H 156 M3 42900 1482 93681 M 1700 M3 340 10540 H 2 8384 3.8 35453 300 H 39390 1449 88752 1 STOO 48 7831 2 7506 3.8 31740 3 17100 144 23493 833 H2 358190 H 353 H3 97075 3354 211984 e 8000 2. 1 18695 4 1400 2.1 3272 48 168000 1.34 250514 1 36540 2.4 97S88 2 26000 1.23 35587 1 3600 6 24036 1 1458 1.34 2174 2 1882 3.8 7958 1 30463 3. 1 105088 1 1275 1.34 1901 2 2800 3.8 11840 1 6020 6 40194 1 1275 1.34 1901 1 904 1.34 1348 1 •47274 1.84 96796 2 1882 3.8 7958 500 H 2 215000 SUB-TOTAL 1903842 ENGINEERING 228461 UFA SUPPLV BIOREACTOR 1. FERMENTER MECHANICAL 2. FERMENTER TANK 3. SUPERNATANT PUMPS 4. SUPERNATANT PIPING 5. SUPNT PUMP INSTN 6. RECVCLE PUMPS 7. RECVCLE INSTN 8. THICKENER BUILDING 1. COMPARTMENTALIZATION 2. ORP PROBES 3. ORP RECORDERS 4. MIXERS LIME TREATMENT OF DIGESTOR SUPERNATANT 1. STORAGE SILOS 2. CHEMICAL FEEDER 3. MIX TANK 4. MIX TANK MIXER 5. HOLDING TANK FD PUMPS 6. HOLDING TANK 7. HOLDING TANK MIXER 8. HOLDING TANK PUMPS 10. RAPID MIX/FLOCCN TNK 11. RAPID MIX MIXER 12. FL0CCN MIXER 13. CLARIFIER MECHANICAL 14. LIME SLUDGE PUMPS 15. BUILDING 20.0 M DIAH, 3.5 n SUD. 4.0 kU CONCRETE EXCAVATION 38 L/f, 19 H TOH, 10.0 kU ISO H H ASTH A53 AS PER FIGURE 3.2 38 L/s, 15 M TDH, 7.9 kU AS PER FIGURE 3.2 COMPETE PARTITIONS 2.4 kU STEEL U/ EPOXV LINER, 203 H3 ROTARV TVPE, 413 kg/hr STEEL, 1.2 H3 0.50 kU 3.8 L/s, 6.0 H TDH, 0.4 kU 109 H3 0.44 kU 0.63 L/s, 3.0 H TDH, 0.04 kU 2.2 M3 0.10 kU 0.01 kU 4.1 H 01AM, 3.0 M SUD, 2.0 kU 0.74 L/s, 10.0 H TDH, 0.15 kU 25 H M 20 H H 8H TOTAL 2132303 N DENOTES INCREMENTAL COST BETUEEN BIO-P tt AN EQUIVALENT CHEMICAL PHOSPHORUS REMOVAL SVSTEH. T A B L E 4.9 - R E G I N A C A P I T A L C O S T S U M M A R Y - 1 7 6 -A s s u m i n g t h a t t h e t o t a l i n c r e m e n t a l c a p i t a l c o s t w o u l d b e e x p e n d e d i n 1 9 9 0 , t h e s i m p l e p a y b a c k p e r i o d f o r t h e i n v e s t m e n t i s 7 . 3 y e a r s . I R R ' s f o r v a r i o u s p r o j e c t l i v e s a r e a s f o l l o w s : P R O J E C T L I F E f y e a r s ) I R R (%) 5 N o R e t u r n 1 0 6 . 6 1 5 1 1 . 4 2 0 1 3 . 0 - 177 -INCREMENTAL ANNUAL COST ($) ITEM 1990-1995 1995-2000 2000-2010 Alum (559,000) (514,000) (593,000) Lime 140,000 125,000 143,000 Sludge D i s p o s a l 44,000 17,000 19,000 N a t u r a l Gas 19,000 30,000 48,000 Power 9,000 9,000 10,000 Operations S t a f f 40,000 40,000 40,000 Maintenance M a t e r i a l s 10,000 10,000 10,000 TOTAL 297,000 283,000 323,000 TABLE 4.10 - REGINA OPERATING COST SUMMARY - 178 -4.4 Saskatoon H. Mclvor Weir Water P o l l u t i o n C o n t r o l  P l a n t 4.4.1 P l a n t D e s c r i p t i o n The H. Mclvor Weir Water P o l l u t i o n C o n t r o l P l a n t p r o v i d e s wastewater treatment f o r the e n t i r e c i t y o f Saskatoon. Located on the South Saskatchewan R i v e r w i t h i n the c i t y l i m i t s , the p l a n t c u r r e n t l y s e r v i c e s a p o p u l a t i o n of approximately 3 154,000 and has a d e s i g n c a p a c i t y of 90,919 m /d based on average d a i l y flow. The p l a n t p r e s e n t l y p r o v i d e s primary treatment and c o n t a i n s s c r e e n i n g , a e r a t e d g r i t removal, primary sedimentation, a n a e r o b i c d i g e s t i o n , c h l o r i n a t i o n and sludge lagoons. Alum i s c u r r e n t l y added t o the primary c l a r i f i e r s t o enhance BOD and SS removal p r i o r t o d i s c h a r g e t o the South Saskatchewan R i v e r . Flowsheets and l a y o u t drawings f o r the p l a n t are presented i n F i g u r e s 4.17 and 4.18 r e s p e c t i v e l y . Primary sludge i s s t a b i l i z e d i n a two-stage anaerobic d i g e s t i o n p r o c e s s . D i g e s t o r gas i s recovered and i s used f o r h e a t i n g . D i g e s t e d sludge i s pumped t o dewatering lagoons approximately 12 km n o r t h of the p l a n t f o r dewatering. SCREENING/ GRIT REMOVAL PC's (2) INFLUENT CI TREATED EFFLUENT TO HEAD OF PLANT PRIMARY SECONDARY DIGESTOR DIGESTOR SLUDGE LAGOONS F I G U R E 4 . 1 7 - S A S K A T O O N P L A N T F L O W S H E E T ( E X I S T I N G ) APPROXIMATE SCALE - 1:1500 SLUDGE PUMPHOUSE HEATING BLDG ADMIN BLDG ANAEROBIC DIGESTORS I l I I _ l I INFLUENT TUNNEL PC PC GRIT TANKS 03 o CHLORINE CONTACT I. TREATED EFFLUENT F I G U R E 4 . 1 8 - S A S K A T O O N P L A N T L A Y O U T ( E X I S T I N G ) - 1 8 1 -D i g e s t o r a n d l a g o o n s u p e r n a t a n t a r e r e t u r n e d t o t h e g r i t c h a m b e r . D e w a t e r e d s l u d g e i s g i v e n a w a y t o i n t e r e s t e d p a r t i e s a s r e q u e s t e d . N o f o r m a l s l u d g e d i s p o s a l p r o j e c t s h a v e b e e n i n i t i a t e d . I t i s l i k e l y t h a t t h e p l a n t m a y b e r e q u i r e d t o u p g r a d e t o s e c o n d a r y t r e a t m e n t w i t h i n t h e n e x t t e n y e a r s . P h o s p h o r u s r e m o v a l r e q u i r e m e n t s w i l l l i k e l y a c c o m p a n y t h i s u p g r a d i n g . E f f l u e n t T P c o n c e n t r a t i o n s o f 1 . 0 m g / L - P a r e a n t i c i p a t e d ( M u n c h , 1 9 8 8 ) . P r e s e n t e f f l u e n t s t a n d a r d s a r e a s f o l l o w s : B 0 D 5 - 1 0 0 m g / L T S S - 1 0 0 m g / L A v e r a g e c o n s t i t u e n t v a l u e s f o r t h e i n f l u e n t t o t h e p l a n t b a s e d o n 1 9 8 5 / 8 6 m o n t h l y a v e r a g e s , a r e a s f o l l o w s : B 0 D 5 - 2 1 3 m g / L T S S - 2 5 5 m g / L T P - 7 . 1 m g / L T m a x - 2 1 ° C T m i n - 9 . 6 ° C I n f l u e n t T K N a n d N H 3 c o n c e n t r a t i o n s a r e n o t m e a s u r e d . H o w e v e r , a v e r a g e e f f l u e n t c o n c e n t r a t i o n s o f 2 7 . 3 m g / L a n d 1 9 . 5 m g / L r e s p e c t i v e l y , w e r e r e a l i z e d d u r i n g t h i s p e r i o d . S i n c e - 182 -n i t r o g e n removal through primary treatment should be minimal, i t w i l l be assumed t h a t these c o n c e n t r a t i o n s are equal t o the i n f l u e n t TKN and NH 3 c o n c e n t r a t i o n s . The p l a n t i s operated by the C i t y . A l a b o r a t o r y with the c a p a b i l i t i e s t o perform a l l a n a l y s i s r e q u i r e d f o r a Bio-P o p e r a t i o n , i s l o c a t e d o n s i t e . 4.4.2 R e t r o f i t M o d i f i c a t i o n s R e t r o f i t d e s i gns were based on the assumption t h a t secondary treatment w i l l be implemented. Assumed e f f l u e n t standards were as f o l l o w s : BOD 5 - 15 mg/L TSS - 15 mg/L TP - 1.0 mg/L-P I t was a l s o assumed t h a t , f o r comparative purposes, a secondary treatment p l a n t employing chemical phosphorus removal would r e q u i r e f o u r new p l u g - f l o w b i o r e a c t o r s having nominal HRT's of 6.0 hours; f o u r new secondary c l a r i f i e r s ; and two new d i g e s t o r s h a ving the same s i z e s as the e x i s t i n g d i g e s t o r s . I t was assumed t h a t g r a v i t y t h i c k e n i n g of primary sludge would not be r e q u i r e d f o r a chemical phosphorus removal f a c i l i t y . - 183 -Flowsheets and l a y o u t drawings f o r the Bio-P removal f a c i l i t y a re p r e s e n t e d i n F i g u r e s 4.19 and 4.20. Layout drawings of the b i o r e a c t o r s are presented i n F i g u r e 4.21. As shown i n the drawings, the f o l l o w i n g t h r e e d i f f e r e n c e s would e x i s t between the Bio-P removal f a c i l i t y and a c o n v e n t i o n a l chemical removal f a c i l i t y : i ) Two g r a v i t y t h i c k e n e r s would be r e q u i r e d t o accommodate primary sludge f e r m e n t a t i o n . i i ) The b i o r e a c t o r s would be m o d i f i e d t o accommodate an a n o x i c / a n a e r o b i c / a e r o b i c sequence. i i i ) F a c i l i t i e s f o r the lime treatment of the d i g e s t o r and lagoon supernatant streams would be r e q u i r e d . The a n o x i c / a n a e r o b i c / a e r o b i c sequence i n the b i o r e a c t o r s i n c o n j u n c t i o n w i t h g r a v i t y t h i c k e n i n g f o r primary sludge f e r m e n t a t i o n was s e l e c t e d , as i t was f e l t t h a t i t minimized both c a p i t a l and o p e r a t i n g c o s t s . T h i s was based on the a n a l y s i s done f o r the Edmonton p l a n t . Continued use of a n a e r o b i c d i g e s t i o n combined w i t h lime treatment of the supernatant was s e l e c t e d over composting, i n order t o maximize d i g e s t o r gas p r o d u c t i o n and t o make the b e s t use of e x i s t i n g f a c i l i t i e s . SCREENING/ GRIT REMOVAL INFLUENT PC 's (2) FERMENTERS (2) - -1 I I l _ OENOTES BIO-P MODIFICATION BIOREACTORS (4) — I F SC's (<V) _i J WAS TO HEAD OF PLANT r I LIME I I I PRIMARY DIGESTORS SECONDARY DIGESTORS SLUDGE LAGOONS TREATED EFFLUENT CO F I G U R E 4 . 1 9 - S A S K A T O O N R E T R O F I T F L O W S H E E T APPROXIMATE SCALE - 1:1500 ANAEROBIC DIGESTORS LIME FACILITY INFLUENT GRIT TANKS CHLORINE CONTACT SC BIOREACTOR sc BIOREACTOR sc BIOREACTOR sc BIOREACTOR 1' TREATED EFFLUENT 'I SLUDGE PUMPHOUSE HEATING BLDG ADMIN BLDG FERMENTER F I G U R E 4 . 2 0 - S A S K A T O O N R E T R O F I T L A Y O U T 6 * 10 m - 60 o CM I ^ i o l o i a i F ^ i 4 ° O O1 O O TO SC's CELL STATUS o-HRT (HRS) 1,2 UNAERATED 0.5 3-5 AERATED/ 0.5 UNAERATED 6 AERATED 0.5 7 AERATED 3.0 MIXER 1 FERMENTER SUPERNATANT FROM PC's H 00 CTi F I G U R E 4 . 2 1 - S A S K A T O O N R E T R O F I T B I O R E A C T O R L A Y O U T - 187 -As shown i n F i g u r e 4.20, the fermenters would be l o c a t e d n o r t h o f the e x i s t i n g d i g e s t o r s . Fermenters would be l o c a t e d below grade f o r i n s u l a t i o n purposes. The e x i s t i n g t u n n e l system would be expanded t o connect the fermenters. Fermenter supernatant p i p i n g would be run i n the t u n n e l s u n t i l i t reached the b i o r e a c t o r s . I t would then be run along the i n s i d e w a l l s of the b i o r e a c t o r s . V a l v e s would be p r o v i d e d such t h a t the V F A - r i c h supernatant c o u l d be i n t r o d u c e d a t a number of p o i n t s along the b i o r e a c t o r . There would be minimal d i f f e r e n c e s between the Bio-P b i o r e a c t o r s and those r e q u i r e d f o r a chemical removal p r o c e s s . Concrete d i v i d e r s would be i n s t a l l e d t o form the anaerobic and anox i c zones. The a i r supply p i p i n g (assuming t h a t a d i f f u s e d a i r system was used) would be equipped w i t h v a l v e s t o f a c i l i t a t e a e r a t e d o r unaerated c o n d i t i o n s i n c e l l s 3, 4 and 5. Mixers would be i n s t a l l e d i n these zones and ORP probes and r e c o r d e r s would be p r o v i d e d . I t was assumed t h a t automatic DO c o n t r o l would be p r o v i d e d i n a f a c i l i t y of t h i s s i z e r e g a r d l e s s of the method of phosphorus removal s e l e c t e d . The p l a n t would operate a t an SRT of 6.5 days. C a l c u l a t i o n s i n d i c a t e t h a t a t t h i s SRT, n i t r i f i c a t i o n would not occur a t wastewater temperatures below 16°C. T h e r e f o r e , i t i s expected t h a t n i t r i f i c a t i o n would o n l y occur d u r i n g the summer - 188 -months and hence, the a n o x i c / a n a e r o b i c / a e r o b i c p r o c e s s would on l y be operated d u r i n g t h i s p e r i o d of time. During the remainder of the y e a r the p r o c e s s would be operated as an a n a e r o b i c / a e r o b i c p r o c e s s . F a c i l i t i e s f o r the lime treatment of d i g e s t o r and lagoon supernatant would be l o c a t e d on the p l a n t s i t e . Lime sludge would be pumped t o the secondary d i g e s t o r s and would t h e r e f o r e e v e n t u a l l y be dewatered i n the lagoons. C a l c u l a t i o n s show t h a t a d d i t i o n a l lagoon area (approximately 3 acres) would be r e q u i r e d t o accommodate the a d d i t i o n a l sludge volumes a s s o c i a t e d w i t h the lime treatment. A comparison of the o p e r a t i n g parameters between a Bio-P and a chemical removal f a c i l i t y i s presented i n Table 4.11. F o r t h i s comparison i t was assumed t h a t alum would be used f o r chemical phosphorus removal. As shown, Bio-P removal r e s u l t s i n reduced alum consumption, oxygen consumption under n i t r i f y i n g c o n d i t i o n s , and methane p r o d u c t i o n , and i n c r e a s e d lime and power consumption, oxygen demand under n o n - n i t r i f y i n g c o n d i t i o n s and s t a f f i n g requirements. I t was assumed t h a t one a d d i t i o n a l f u l l - t i m e o p e r a t o r would be r e q u i r e d t o operate the lime treatment and f e r m e n t a t i o n f a c i l i t i e s . - 189 -P A R A M E T E R B I O - P CASE CHEMICAL P CASE A l u m C o n s u m p t i o n ( k g / d ) 917 7,335 L i m e C o n s u m p t i o n ( k g / d ) 3,508 S l u d g e P r o d u c t i o n - M a s s ( k g / d ) 16,598 14,034 - V o l u m e ( m 3 / d ) 150 122 O x y g e n D e m a n d ( k g / d ) - w / o N i t r i f i c a t i o n 7,018 6,196 - w / N i t r i f i c a t i o n 13,951 14,299 M e t h a n e P r o d u c t i o n ( m 3 / d ) 9,310 10,454 I n c r e m e n t a l P o w e r C o n s u m p t i o n (kw) - w / o N i t r i f i c a t i o n +49.5 - w / N i t r i f i c a t i o n +12.0 I n c r e m e n t a l O p e r a t i o n s S t a f f +1 T A B L E 4 . 1 1 - S A S K A T O O N O P E R A T I O N S C O M P A R I S O N 3 B a s e d o n a n i n f l u e n t f l o w o f 90,919 m / d . - 190 -I t s hould be noted t h a t a s m a l l amount o f alum (10 mg/L) would pr o b a b l y be r e q u i r e d t o t r i m s o l u b l e phosphorus c o n c e n t r a t i o n s , t o ensure t h a t e f f l u e n t standards are met. 4 . 4.3 Cost A n a l y s i s A summary of the incremental c a p i t a l c o s t s a s s o c i a t e d w i t h Bio-P removal i s presented i n Table 4.12. As shown, the t o t a l i n c r e m e n t a l c o s t i s estimated t o be approximately $2,258,000. A summary of the incremental o p e r a t i n g c o s t s i s p r e s e n t e d i n T a b l e 4.13. As i n d i c a t e d , the use of Bio-P removal w i l l r e s u l t i n annual savings of approximately $270,000. Based on these estimates, the simple payback p e r i o d f o r the c a p i t a l investment i s 8 . 4 y e a r s . IRR's f o r the investment f o r v a r i o u s p r o j e c t l i v e s are as f o l l o w s : PROJECT LIFE (years) IRR (%) 5 No Return 10 3.7 15 8.7 20 10.5 TOTAL MATERIAL INSTALLED MODIFICATION ITEM SPECIFICATION QUANTITV COST INSTALLATION BULK COST <*•> MANHOURS FACTOR <»> UFA SUPPLV 2. BIOREACTOR 1. FERMENTER MECHANICAL 2. FERMENTER TANK 3. SUPERNATANT PUMPS I . SUPERNATANT PI PINO 5. SUPNT INSTRUMENTATION 6. RECVCLE PUMPS 7. RECVCLE INSTN 0. WASTE PUMPS 10.UASTE PUMP INSTN II . TUNNEL EXPANSION 1. COMPARTMENTALIZATION 2. ORP PROBES 3. ORP RECORDERS 4. MIXERS A. LAOOON EXPANSION 1S.0 M DIAM, CONCRETE EXCAVATION 26.3 L/s, 21 H TDH, 100 MH ASTM A53 AS PER FIOURE 3.2 26.3 L/s, 15.0 M TDH, AS PER FIOURE 3.2 26.3 L/s, 26.5 H TOH, AS PER FIOURE 3.2 EXCAVATION CONCRETE CONRETE PARTITIONS 2.A kU, 1640 rpn 3.5 M SUD, 3.0kU 7.6 kU 5.5 kU 9.6 kU 3. LIME TREATMENT OF DIGESTOR SUPERNATANT 1. STORAGE SILOS 2. CHEMICAL FEEDER 3. MIX TANK A. MIX TANK MIXER 5. HOLOINO TANK FD PUMPS 6. HOLDING TANK 7. HOLDING TANK MIXER B. HOLDING TANK PUMPS 9. RAPID MIX/FLOCCN TNK 10. RAPID MIX MIXER 11. FLOCCN MIXER 12. CLARIFIER MECHANICAL 13. LI ME SLUDGE PUMPS 14. BUILDING 1. COMPACTED FILL 2. CLEARING/DRUBBING 3. STRIPPING 4. CLAV LINER 5. PIPING STEEL U/ EPOXV LINER, 113 M3 ROTARV TVPE, 450 kg/hr STEEL, 1.2 M3 0.50 kU 4.0 L/s, 6.0 M TDH, 0.40 kU STEEL, 697 M3 2.4 kU 4.0 L/s, 3.0 H TOH, 0.20kU STEEL, 4.8 H3 0.24 kU 0.12 kU STEEL TNK, 6.1 M D, 3.0 M SUD 0.9 L/s, 10.0 n TDH, 0.17 kU 35 M m 20 H « 7M 0.67 H HIGH BERMS 0.30 M TOPSOIL 150 MM THICK 150 MM ft 200 MM ASTM A53 2 160000 1.84 312448 1B0 M3 49500 1710 108094 1600 M3 320 9920 2 7506 3.8 29369 30O M 31230 1341 76324 1 5700 48 7831 2 6040 3.8 23633 1 5700 48 7831 2 8384 3.8 32805 1 5700 48 7831 120O M3 240 7440 96 M3 26400 936 58394 300 M3 82500 2850 180156 8 8000 2.1 17702 4 1400 2. 1 3098 40 4004 2 8459 2 41000 2.2 94825 2 260OO 1.23 34913 1 3600 6 22006 1 1691 1.34 2457 3764 3.8 14728 1 73500 1.7 133241 1 3500 1.34 5085 3764 3.8 14728 1 8640 5.3 46767 1 1275 1.34 1652 1 1275 1.34 1852 1 66000 2.2 152645 2 3764 3.8 14728 700 M2 3010OO 2600 M3 13000 520 30586 6.25 h« 32031 18750 M3 12188 9375 M3 46875 1875 110288 750 H 32160 2029 98681 SUB-TOTAL 2015934 ENGINEERING 241912 H H TOTAL 2257846 T A B L E 4.12 - S A S K A T O O N C A P I T A L C O S T S U M M A R Y - 192 -ITEM ANNUAL COST 1. Alum ($504,000) 2. Lime 150,000 3. N a t u r a l Gas 30,000 4. Power 7,000 5. Oper a t i o n s S t a f f 40,000 6. Maintenance M a t e r i a l s 7,000 TOTAL 1^270^0001 TABLE 4.13 - SASKATOON OPERATING COST SUMMARY - 193 -4.5 Windsor L i t t l e R i v e r P o l l u t i o n C o n t r o l P l a n t 4.5.1 P l a n t D e s c r i p t i o n The C i t y of Windsor i s l o c a t e d i n southern O n t a r i o a c r o s s the D e t r o i t R i v e r from D e t r o i t , Michigan. The L i t t l e R i v e r P o l l u t i o n C o n t r o l P l a n t i s the l a r g e r of two wastewater treatment p l a n t s s e r v i c i n g the c i t y and c u r r e n t l y has a design 3 c a p a c i t y of 36,281 m /d based on average d a i l y flow. A 27,211 3 . m /d expansion t o the p l a n t i s c u r r e n t l y i n p r o g r e s s . The e x i s t i n g p l a n t uses the c o n v e n t i o n a l a c t i v a t e d sludge p r o c e s s and c o n t a i n s s c r e e n i n g , a e r a t e d g r i t removal, primary sedimentation, d i f f u s e d a i r and mechanical a e r a t i o n , secondary sedimentation, c e n t r i f u g i n g and c h l o r i n a t i o n u n i t o p e r a t i o n s . The p l a n t expansion w i l l i n v o l v e the i n s t a l l a t i o n of new primary c l a r i f i e r s , b i o r e a c t o r s , secondary c l a r i f i e r s and sludge pumping f a c i l i t i e s . The new f a c i l i t i e s w i l l share g r i t removal and sludge h a n d l i n g o p e r a t i o n s w i t h the e x i s t i n g p l a n t , but w i l l e s s e n t i a l l y operate independently. Flowsheets and l a y o u t drawings f o r the expanded p l a n t are p r e s e n t e d i n F i g u r e s 4.22 and 4.23. EXISTING PLANT (36,281 m3/d) PC'. (4) GRIT REMOVAL Al SC's (4) V TREATED EFFLUENT PC'« (2) EXPANSION (27,211 m3/d) BIOREACTORS Al SC'« (2) CI VO TREATED EFFLUENT TO LIME STABILIZATION & DISPOSAL CENTRIFUGES SLUDGE HOLDING TANK F I G U R E 4 . 2 2 - W I N D S O R C O M B I N E D P L A N T F L O W S H E E T ( E X I S T I N G ) F I G U R E 4 . 2 3 - W I N D S O R C O M B I N E D P L A N T L A Y O U T ( E X I S T I N G ) - 196 -As shown i n F i g u r e 4.22, raw wastewater c u r r e n t l y passes through two g r i t removal chambers and i s then d i s t r i b u t e d t o f o u r primary c l a r i f i e r s . Two a d d i t i o n a l primary c l a r i f i e r s w i l l be c o n s t r u c t e d f o r the p l a n t expansion. Primary e f f l u e n t i s c u r r e n t l y r o u t e d t o f o u r b i o r e a c t o r s . Each b i o r e a c t o r c o n t a i n s f o u r zones. T o t a l nominal HRT of the b i o r e a c t o r s i s 3.23 hours. A e r a t i o n i s v i a a combination of mechanical d i f f u s e d a i r a e r a t i o n . The most n o r t h e r n b i o r e a c t o r uses f o u r mechanical s u r f a c e a e r a t o r s whereas the southern t h r e e r e a c t o r s u t i l i z e d i f f u s e d a i r s u p p l i e d by t h r e e c e n t r i f u g a l blowers. Automatic DO c o n t r o l i s not p r o v i d e d i n the e x i s t i n g p l a n t . Spent aluminum c a t a l y s t i s added t o the r e a c t o r s f o r phosphorus removal. The p l a n t expansion w i l l i n v o l v e the c o n s t r u c t i o n of f o u r new b i o r e a c t o r s , s i m i l a r i n l a y o u t t o the e x i s t i n g p l a n t . The HRT o f these r e a c t o r s w i l l be i n c r e a s e d t o accommodate a n i t r i f i c a t i o n requirement. D i f f u s e d a i r a e r a t i o n w i l l be used and automatic DO c o n t r o l w i l l be p r o v i d e d . B i o r e a c t o r mixed l i q u o r i s p r e s e n t l y s e t t l e d i n f o u r secondary c l a r i f i e r s . Secondary e f f l u e n t i s c h l o r i n a t e d and then d i s c h a r g e d t o the L i t t l e R i v e r . Two new c l a r i f i e r s w i l l be c o n s t r u c t e d f o r the p l a n t expansion. - 197 -Sludge i s wasted from the secondary c l a r i f i e r s t o e i t h e r the primary c l a r i f i e r s o r the raw sewage wet w e l l . Primary sludge i s pumped t o a h o l d i n g tank, c h e m i c a l l y c o n d i t i o n e d w i t h polymer and dewatered i n t h r e e c e n t r i f u g e s . Dewatered sludge cake having a s o l i d s content from 13 t o 21 pe r c e n t , i s t r u c k e d by the c i t y t o a p r i v a t e l y owned lime s t a b i l i z a t i o n s i t e where a waste lime product i s added t o r a i s e the s o l i d s c o n t e n t t o a t l e a s t 40 per c e n t . A p r i v a t e c o n t r a c t o r then h a u l s the sludge t o a d i s p o s a l s i t e approximately 80 k i l o m e t e r s e a s t o f the C i t y . O n t a r i o M i n i s t r y o f the Environment (OME) standards f o r the e x i s t i n g p l a n t e f f l u e n t (based on monthly averages) are as f o l l o w s : BOD 5 - 15 mg/L TSS - 15 mg/L TP - 1.0 mg/L-P As o f August 1987, standards f o r the new p l a n t were not e s t a b l i s h e d . However, the f o l l o w i n g requirements were a n t i c i p a t e d (Romano, 1987): BOD 5 - 5 mg/L TSS - 5 mg/L TP - 0.3 mg/L-P (May through October) 1.0 mg/L-P (November through A p r i l ) - 198 -NH 3 - 1.0 mg/L-N (May through October) 4.0 mg/L-N (November through A p r i l ) Average c o n c e n t r a t i o n s f o r the parameters o f i n t e r e s t i n t he i n f l u e n t sewage (based on 1985/86 averages) are as f o l l o w s : BOD 5 - 110 mg/L TSS - 155 mg/L TKN - 23 mg/L NH 3 - 15 mg/L TP - 5.2 mg/L Tmax - 20°C Tmin - 5°C Performance o f the p l a n t has been good w i t h the f o l l o w i n g average e f f l u e n t c o n c e n t r a t i o n s and compliance r e s u l t s a c h i eved f o r 1985 (1986 data not o b t a i n e d ) : Average E f f l u e n t C o n c e n t r a t i o n Monthly Compliances Parameter (mq/L) (Maximum 12) B0D c 5.3 12 o TSS 9.5 12 TP 0.82 9 - 199 -The e x i s t i n g p l a n t i s not designed t o n i t r i f y but a review o f l a b o r a t o r y a n a l y s i s r e s u l t s i n d i c a t e s t h a t some n i t r i f i c a t i o n does occur i n the summer months a t the o p e r a t i n g SRT. The p l a n t i s operated by the C i t y and i s equipped w i t h an o n s i t e l a b o r a t o r y capable o f performing a l l Bio-P r e l a t e d a n a l y s e s . However, s i n c e the p l a n t does not have anaerobic d i g e s t o r s , VFA a n a l y s i s i s not performed. A f u l l - s c a l e Bio-P removal t e s t was c a r r i e d out a t the L i t t l e R i v e r P l a n t from June 1985 t o March 1986. In the t e s t , the two south b i o r e a c t o r s were m o d i f i e d t o achieve a p l u g - f l o w a n a e r o b i c / a e r o b i c sequence. VFA c o n c e n t r a t i o n s were monitored i n the primary e f f l u e n t and c o r r e l a t e d w i t h phosphorus removal performance. Good phosphorus removal was i n i t a l l y a c h i eved w i t h average e f f l u e n t TP's of 1.17 mg/L r e a l i z e d f o r June 1985 ( C i t y o f Windsor, 1985). During t h i s p e r i o d of time VFA c o n c e n t r a t i o n s i n t he i n f l u e n t sewage exceeded 15 mg/L HAc. However, VFA c o n c e n t r a t i o n s decreased over the f o l l o w i n g months and hence, Bio-P removal was l o s t . T h e r e f o r e , primary sludge f e r m e n t a t i o n was recommended should Bio-P removal be implemented on a f u l l - s c a l e b a s i s (Oldham, 1986). - 200 -4.5.2 R e t r o f i t M o d i f i c a t i o n s Bio-P removal flowsheets and l a y o u t drawings f o r the p l a n t a re pres e n t e d i n F i g u r e s 4.24 and 4.25. In a d d i t i o n , b i o r e a c t o r l a y o u t s are presented i n F i g u r e 4.26. As shown on the drawings, t h r e e s i g n i f i c a n t m o d i f i c a t i o n s would be r e q u i r e d t o both the e x i s t i n g p l a n t and the proposed new p l a n t t o accommodate Bio-P removal. The f i r s t i n v o l v e s i n s t a l l i n g g r a v i t y t h i c k e n e r s f o r primary sludge f e r m e n t a t i o n . T h i c k e n e r s were s e l e c t e d over completely mixed fermenters as they r e s u l t i n reduced sludge volumes and permit the use of an a n o x i c / a n a e r o b i c / a e r o b i c sequence i n the b i o r e a c t o r , thereby e l i m i n a t i n g the requirement f o r mixed l i q u o r r e c y c l e pumps a s s o c i a t e d w i t h c o n v e n t i o n a l Bio-P p r o c e s s e s . I n d i v i d u a l fermenters would be p r o v i d e d f o r both the e x i s t i n g p l a n t and the new p l a n t . The fermenter f o r the e x i s t i n g p l a n t would be l o c a t e d south o f the b i o r e a c t o r s . Supernatant, r e c y c l e and wastage pumps would be l o c a t e d i n Sludge Pump B u i l d i n g No. 2. P i p i n g between the fermenter and the pumphouse would be run underground. Supernatant p i p i n g would be run through the e x i s t i n g t u n n e l t o Sludge Pump B u i l d i n g No. 1, and then t o the b i o r e a c t o r s . The new fermenter wastage pumps would be t i e d i n t o the e x i s t i n g primary sludge headers l e a d i n g t o the sludge s t o r a g e v a u l t l o c a t e d i n the dewatering b u i l d i n g . GRIT REMOVAL EXISTING PLANT (36,281 m3/d) PC'S (4) BIOREACTORS Al CI SC's (4) V TREATED EFFLUENT PC's (2) EXPANSION (27,211 m3/d) BIOREACTORS CI SC's (2) TREATED EFFLUENT DENOTES BIO-P MODIFICATION TO LIME STABILIZATION & DISPOSAL to o F I G U R E 4 . 2 4 - W I N D S O R R E T R O F I T F L O W S H E E T APPROXIMATE SCALE - 1:1750 LITTLE RIVER B - SLUDGE PUMP BUILDING ' . _ DENOTES BIO-P MODIFICATION F I G U R E 4 . 2 5 - W I N D S O R R E T R O F I T L A Y O U T NEW PLANT (27211 m3/D) EXISTING PLANT (36281 m3/D) FROM PC's TO SC's FERMENTER SUPNT 1 — 5 o o L ' -5 -fx--fx--tXH FROM PC s CELL STATUS HRT (HRS) 1,2 UNAERATED 1.0 3,4 AERATED/ 1.0 UNAERATED 5 AERATED 1.0 6 AERATED 5.0 TO SC's FERMENTER SUPNT o - — ) ~ ) -tx3— CELL STATUS HRT (HRS) 1,2 UNAERATED 0.6 3,4 AERATED/ 0.6 UNAERATED 5 AERATED 2.4 19 O ~ MIXER 20 III F I G U R E 4 . 2 6 - W I N D S O R R E T R O F I T B I O R E A C T O R L A Y O U T S - 204 -The fermenter f o r the new p l a n t would be l o c a t e d south o f the new b i o r e a c t o r s . A l l pumps would be l o c a t e d i n Sludge Pump B u i l d i n g No. 3 and a l l i n t e r c o n n e c t i n g p i p i n g would be run underground. The second major m o d i f i c a t i o n i n v o l v e s m o d i f y i n g the b i o r e a c t o r s t o accommodate the r e q u i r e d a n a e r o b i c and anoxic zones. Again, an a n o x i c / a n a e r o b i c / a e r o b i c sequence was s e l e c t e d as i t p r o v i d e s o p e r a t i n g f l e x i b i l i t y and minimizes c a p i t a l c o s t s . S i g n i f i c a n t m o d i f i c a t i o n s were r e q u i r e d t o c o n v e r t the e x i s t i n g b i o r e a c t o r s f o r Bio-P removal. C a l c u l a t i o n s showed t h a t n i t r i f i c a t i o n would occur d u r i n g the summer a t the d e s i g n SRT of 6.5 days and t h a t an anoxic HRT of 1.0 hour would be r e q u i r e d t o d e n i t r i f y the RAS. Since an anaerobic HRT of 1.0 hour i s a l s o r e q u i r e d , the a e r o b i c HRT would be reduced t o 1.2 3 hours, or 38 p e r c e n t o f the t o t a l HRT. Ekama and Marais (1984) note t h a t i f a e r o b i c HRT's are allowed t o drop below 50 pe r c e n t , sludge s e t t l e a b i l i t y problems w i l l r e s u l t . T h e r e f o r e , i t was concluded t h a t the e x i s t i n g r e a c t o r s were too s m a l l t o support Bio-P removal and t h a t a d d i t i o n a l r e a c t o r volume was r e q u i r e d . As a r e s u l t , two a d d i t i o n a l r e a c t o r s , i d e n t i c a l t o the e x i s t i n g r e a c t o r s , would be r e q u i r e d . These would be l o c a t e d south of the e x i s t i n g secondary b a s i n s . The a d d i t i o n of these r e a c t o r s would i n c r e a s e the t o t a l nominal HRT t o 4.84 hours. - 205 -O p e r a t i o n of the b i o r e a c t o r s would be s i m i l a r t o t h a t used i n the Bio-P t e s t . As shown i n F i g u r e 4.26, primary e f f l u e n t would be i n t r o d u c e d a t the west end of t h r e e of the r e a c t o r s and would flow e a s t through the anoxic ( i f n i t r i f i c a t i o n i s o c c u r r i n g ) and anaerobic zones. At the end of the r e a c t o r i t would pass through an opening i n the d i v i d i n g w a l l (to be c o n s t r u c t e d ) i n t o the adjacent r e a c t o r , and then flow west and e x i t over the weir. As a r e s u l t , t h r e e r e a c t o r s c o n t a i n i n g e i g h t c e l l s each, would be c r e a t e d . The e x i s t i n g r e a c t o r s have p a r t i a l d i v i d i n g w a l l s s e p a r a t i n g the zones. These w a l l s would be extended f o r the anoxic and a naerobic zones of a Bio-P p l a n t . The a i r supply system i s g e n e r a l l y w e l l set-up i n the e x i s t i n g r e a c t o r s f o r Bio-P removal, as v a l v e s are a v a i l a b l e t o shut o f f the supply t o each zone. Mechanical a e r a t o r s would co n t i n u e t o be used i n the n o r t h r e a c t o r . However, the a e r a t o r s i n the f i r s t two zones would be t u r n e d o f f t o c r e a t e anaerobic and anoxic c o n d i t i o n s . Mixers would be i n s t a l l e d i n a l l non-aerated or p o t e n t i a l l y non-aerated zones. New a i r supply p i p i n g would be r e q u i r e d t o s e r v i c e the a d d i t i o n a l r e a c t o r s c o n s t r u c t e d . A d d i t i o n a l blowers would not be r e q u i r e d as the e x i s t i n g ones were found t o be adequate. Area l i g h t i n g would a l s o be r e q u i r e d f o r the new r e a c t o r s . - 206 -As p r e v i o u s l y mentioned, automatic DO c o n t r o l i s not p r e s e n t i n the e x i s t i n g p l a n t . T h i s would be p r o v i d e d through the i n s t a l l a t i o n o f DO probes, p r o c e s s c o n t r o l l e r s and c o n t r o l v a l v e s on the i n l e t t o the blowers. ORP probes and r e c o r d e r s would a l s o be i n s t a l l e d . M o d i f i c a t i o n s t o the b i o r e a c t o r s f o r the new p l a n t would be r e l a t i v e l y minimal. Because the p l a n t w i l l be designed f o r n i t r i f i c a t i o n , i t was determined t h a t the r e a c t o r s i z e s w i l l be adequate t o accommodate Bio-P removal. In a d d i t i o n , automatic DO c o n t r o l w i l l be p r o v i d e d . T h e r e f o r e , the o n l y m o d i f i c a t i o n s r e q u i r e d would be the i n s t a l l a t i o n o f d i v i d i n g w a l l s and mixers f o r the anaerobic and anoxic zones, and ORP m o n i t o r i n g f a c i l i t i e s . The t h i r d and f i n a l major m o d i f i c a t i o n i n v o l v e s the sludge h a n d l i n g f a c i l i t i e s . The pr e s e n t p r a c t i c e o f s e t t l i n g WAS i n the primary c l a r i f i e r would r e s u l t i n the sludge b e i n g exposed t o a n a e r o b i c c o n d i t i o n s i n the bottom of the c l a r i f i e r and the fermenter and hence, would r e s u l t i n phosphorus r e l e a s e . T h e r e f o r e , i n a Bio-P removal f a c i l i t y , WAS would be t h i c k e n e d s e p a r a t e l y i n a d i s s o l v e d a i r f l o t a t i o n u n i t (DAF) and then r o u t e d t o the c e n t r i f u g e s . A s i n g l e DAF u n i t f o r both p l a n t s would be i n s t a l l e d n o r t h of the blower b u i l d i n g . P i p i n g from the e x i s t i n g p l a n t t o the DAF would be run underground. New WAS - 207 -pumps would not be r e q u i r e d . P i p i n g from the new p l a n t t o the DAF u n i t would be run t o the end of the e x i s t i n g t u n n e l s and would then c o n t i n u e underground. I t was assumed t h a t the WAS pumps would have s u f f i c i e n t head t o pump the sludge t o the DAF. Pumps and p i p i n g would be r e q u i r e d t o pump both the DAF sludge t o the c e n t r i f u g e s , and the DAF subnatant t o the head o f the p l a n t . A l l p i p i n g would be l o c a t e d underground. Incremental o p e r a t i n g and maintenance requirements f o r a Bio-P o p e r a t i o n i n c l u d e VFA a n a l y s i s , DO probe c l e a n i n g i n the e x i s t i n g p l a n t , ORP probe c l e a n i n g , fermenter o p e r a t i o n and maintenance, and DAF o p e r a t i o n and maintenance. I t was f e l t t h a t one a d d i t i o n a l person would have t o be h i r e d as a r e s u l t o f t h i s . A comparison of the o p e r a t i n g parameters f o r a Bio-P removal f a c i l i t y , w i t h those f o r an e q u i v a l e n t chemical phosphorus removal f a c i l i t y are presented i n Tab l e 4.14. As shown i n t h i s t a b l e , Bio-P removal r e s u l t s i n reduced chemical consumption, oxygen demand and sludge p r o d u c t i o n . However, because o f the a d d i t i o n of the fermenting and DAF o p e r a t i o n s , power consumption i s i n c r e a s e d . I t should be noted t h a t phosphorus removal chemicals (25 mg/L of the aluminum c a t a l y s t s o l u t i o n ) w i l l be r e q u i r e d i n c o n j u n c t i o n w i t h Bio-P removal, t o reduce s o l u b l e phosphorus c o n c e n t r a t i o n s i n or d e r t o achieve the e f f l u e n t TP standard. - 208 -4.5.3 Cost A n a l y s i s Cost analyses were prepared f o r the e x i s t i n g f a c i l i t y , t he new f a c i l i t y and the combined f a c i l i t y . Incremental c a p i t a l c o s t s are pre s e n t e d i n Table 4.15 and 4.16. As shown, i n c r e m e n t a l c a p i t a l c o s t s f o r the e x i s t i n g , new and combined f a c i l i t i e s are $2,074,000, $970,000 and $3,044,000, r e s p e c t i v e l y . S i n c e o n l y a s i n g l e DAF u n i t was proposed, c o s t s f o r the e x i s t i n g and new f a c i l i t i e s were p r o - r a t e d based on flow. A summary of the incremental o p e r a t i n g c o s t s i s pr e s e n t e d i n Tab l e 4.17. Annual sa v i n g s of $48,000, $43,000 and $91,000 would be r e a l i z e d f o r the e x i s t i n g , new and combined f a c i l i t i e s , r e s p e c t i v e l y . Based on these estimates simple payback p e r i o d s f o r the c a p i t a l investments are as f o l l o w s : E x i s t i n g F a c i l i t y 43 years New F a c i l i t y 23 y e a r s Combined F a c i l i t y 33 years Because of the d u r a t i o n of these payback p e r i o d s , t h e r e i s no r a t e o f r e t u r n on the investment f o r p r o j e c t l i v e s o f 5, 10, 15 and 20 y e a r s . - 209 -PARAMETER 1. Alum C a t a l y s t Consumption (kg/d) 2. Oxygen Demand (kg/d) w/o N i t r i f i c a t i o n i n e x i s t i n g p l a n t - w/ N i t r i f i c a t i o n i n e x i s t i n g p l a n t 3. Sludge P r o d u c t i o n 1 " (kg/d) 4. Incremental Power Consumption (kw) 5. Incremental Operations S t a f f BIO-P CASE CHEMICAL P CASE 1,481 10,581 5,885 5,708 9,192 9,519 22,615 25,913 +10 1 TABLE 4.14 - WINDSOR OPERATIONS COMPARISON 1. 1. Lime s t a b i l i z e d sludge. Based on combined i n f l u e n t flow of 63,492 m /d. TOTAL MATERIAL BULK INSTALLED MODIFICATION ITEM SPECIFICATION OUANTITV COST INSTALLATION FACTOR COST <*•> MANHOURS <•> 1. UFA SUPPLV 2. EXISTING BIOREACTORS NEW BIOREACTOR SLUDOE HANDLINO SUPERNATANT 1. FERMENTER MECHANICAL 11.9 M DIAH, 3.5 M SMD, 2.5kM 1 55000 1.84 105248 2. FERMENTER TANK CONCRETE 61 M3 16775 580 35411 EXCAVATION 472 M3 12 378 3. SUPERNATANT PUMPS 10.5 L/s. 20.0 M TDH. 2 .9 kU 2 4440 3.8 17S47 4. SUPERNATANT PIPING 100 MM ASTN A53 250 M 26025 1118 61709 5. SUPNT PIPING EXCUN 150 MS 30 930 6. SUPNT INSTRUMENTATION AS PER FIGURE 3.2 1 5700 48 7416 r . RECVCLE PUMPS 10.5 L/s, 49.0 M TDH, 9 .A k U 2 8384 3.8 33134 s . RECVCLE INSTN AS PER FIGURE 3.2 1 5700 48 7416 9. UASTE PUMPS 10.5 L/s, 26.5 M TDH, 3 .90 kM 2 4440 3.8 17547 10.MASTE PUMP INSTN AS PER FIGURE 3.2 1 5700 48 7416 1. COMPARTMENTALIZATION CONRETE PARTITIONS 25 M3 6875 238 14513 2. DO PROBES A 14000 2. 1 30576 3. DO CONTROL INSTN AS PER SECTION 3 25800 301 36163 4. 00 CONTROL PANEL 2 M 5000 1.96 10192 5. ORP PROBES A 4000 2. 1 8736 6. ORP RECORDERS 2 700 2. 1 1529 7. MIXERS 1.2 kU EA. 8 16000 1.39 23130 8. DISMANTLE AERATORS A 288 8928 9. AIR PIPING 150 MM ASTH A53 100 M 13130 483 28628 1. EXCAVATION 2676 M3 535 16591 2. CONCRETE 1100 H3 302500 1045O 638550 3. AREA LIGHTING 732 M2 30012 1171 67520 A. PIPING 200 MM ASTM A53 10O M 15850 519 32573 5. DO PROBES 2 7000 2. 1 15288 6. DO CONTROL INSTN AS PER FIGURE 3.3 5000 142 9602 9. NEU AERATION 3.7 kM EA. TURBORATORS A 20O0O 1.8 37440 5.0 kM EA. TURBORATORS 8 72000 1.8 134784 10.ORP PROBES 2 2000 2. 1 4368 11.ORP RECORDERS 1 350 2.1 764 12.MIXERS 1.2 kU EA. A 8000 1.39 11565 1. DAF UNIT 36 H2, 2773 kg/d 1 152S71 1.6 253879 2. DAF BUILOINO 10.0 H M 8.0 M 86 M2 36857 3. UAS PIPINO 150 MM ASTN AS3 100 M 13130 483 28628 A. U A S PIPE EXC/BCKFL 288 M3 115 3571 5. MAS PIPE PAVING 50 M3 12500 230 2.8 20130 6. OAF SLUDOE PIPING 150 MM ASTN AS3 86 11254 414 24538 7. OAF PIPE EXC/BCKFL 247 M3 99 3061 8. DAF PIPE PAVING 43 M3 10714 197 172S4 9. DAF SLUDOE PUMPS 0.9 L/s i , 10 M TDH, 0.20 kU 2 2151 3.8 8500 10. DAF SBNT PIPING 100 MM Asm A53 86 M 8923 383 21157 11. DAF SBNT PUMPS 3.7 L/s :, 6.0 H TDH, 0.40 k U 2 2151 4.05 9059 I to H O I SUB-TOTAL 1852226 ENGINEERING 222267 TOTAL 2074493 T A B L E 4 . 1 5 - W I N D S O R C A P I T A L C O S T S U M M A R Y ( E X I S T I N G F A C I L I T Y ) MODIFICATION ITEM SPECIFICATION TOTAL MATERIAL INSTALLED OUANTITV COST INSTALLATION BULK COST <*> MANHOURS FACTOR <«> 1. UFA SUPPLV 2. EXISTING 3. SLUDOE HANDLINO SUPERNATANT 1. FERMENTER MECHANICAL 2. FERMENTER TANK 3. SUPERNATANT PUMPS 4. SUPERNATANT PIPING 5. SUPNT PIPING EXCUN 6. SUPNT INSTRUMENTATION 7. RECVCLE PUMPS B. RECVCLE INSTN 9. UASTE PUMPS 10. UASTE PUMP INSTN 1. C0MPARTHENTALI2ATI0N 2. ORP PROBES 3. ORP RECORDERS A. MIXERS 1. DAF UNIT 2. DAF BUILDING 3. UAS PIPING A. UAS PIPE EXC/BCKFL 5. UAS PIPE PAVING 6. DAF SLUDOE PIPING 7. DAF PIPE EXC/BCKFL 8. OAF PIPE PAVING 9. DAF SLUDOE PUMPS 1O.0AF SBNT PIPING 11. DAF SBNT PUMPS 10.3 M DIAM, 3.5 M SUD. 2.SkU CONCRETE EXCAVATION 7.9 L/s, 20.0 H TDH, 2.2 kU 100 MM ASTM A53 5.4 k U k U AS PER FIOURE 3.2 7.9 L/s, 49.0 M TDH, AS PER FIOURE 3.2 7.9 L/s, 26.5 M TDH, 2.5 AS PER FIGURE 3.2 CONRETE PARTITIONS 1.2 k U EA. 36 M2, 2773 k g / d 10.0 M M 8.0 H 150 MM ASTN A53 150 MM ASTN A53 0.9 L/s, 10 M TOH, 0.20 k U 100 MM ASTM A53 3.7 L/s, 6.0 H TDH, 0.40 k U 1 65000 1.84 121992 61 M3 16775 580 35075 472 M3 12 378 2 4440 3.8 17209 250 M 26025 1118 61188 150 M3 30 930 1 5700 48 7302 2 6O40 3.8 23411 1 5700 48 7302 2 4440 3.8 17209 1 5700 46 7302 87 M3 23925 827 50025 4 4000 2.1 8568 2 700 2. 1 1499 16 32000 1.39 45370 1 114429 1.6 186747 64 M2 27643 300 M 39390 1449 85097 432 M3 173 5357 75 M3 18750 345 2.8 29820 64 8441 311 18235 165 74 2296 32 M3 8036 148 12780 2 18282 3.8 70862 64 M • 6692 287 15734 2 1613 4.05 6664 SUB-TOTAL 865996 ENGINEERING 103920 I to TOTAL 969915 T A B L E 4 . 1 6 - W I N D S O R C A P I T A L C O S T S U M M A R Y f N E W F A C I L I T Y ) - 212 -INCREMENTAL ANNUAL COST fS) ITEM EXISTING NEW COMBINED 1. Chemical Consumption (43,000) (32,000) (75,000) 2. Sludge D i s p o s a l (31,000) (35,000) (66,000) 3. Power (2,000) 2,000 0 4. Opera t i o n s S t a f f 20,000 20,000 40,000 5. Maintenance M a t e r i a l s 8,000 2 , 000 10,000 TOTAL Xi!=tP=P=°=l 143^0001 121^0001 TABLE 4 . 1 7 - WINDSOR LITTLE RIVER OPERATING COST SUMMARY - 213 -4.6 Grimsby Baker Road P o l l u t i o n C o n t r o l P l a n t 4.6.1 P l a n t D e s c r i p t i o n The town of Grimsby i s l o c a t e d i n southern O n t a r i o , approximately 20 km southeast o f Hamilton. The Baker Road P o l l u t i o n C o n t r o l P l a n t i s the l a r g e r of two wastewater treatment p l a n t s s e r v i c i n g Grimsby. The p l a n t c u r r e n t l y s e r v e s a p o p u l a t i o n o f approximately 2 0,000 and has a d e s i g n c a p a c i t y of 18,184 m3/d. The p l a n t uses the a c t i v a t e d sludge p r o c e s s and c o n t a i n s g r i t removal, primary sedimentation, mechanical a e r a t i o n , secondary sedimentation, a two-stage anaerobic d i g e s t i o n and c h l o r i n a t i o n u n i t o p e r a t i o n s . Flowsheets and l a y o u t drawings f o r the p l a n t are presented i n F i g u r e s 4.27 and 4.28. A f t e r p a s s i n g through a g r i t removal chamber, the wastewater i s d i s t r i b u t e d t o two primary c l a r i f i e r s . Primary e f f l u e n t i s r o u t e d t o a d i s t r i b u t i o n chamber where i t i s mixed w i t h RAS. The mixture then flows t o two completely mixed b i o r e a c t o r s v i a another d i s t r i b u t i o n chamber. Each b i o r e a c t o r c o n t a i n s f o u r 18.7 kW mechanical s u r f a c e a e r a t o r s . Automatic DO c o n t r o l i s not p r o v i d e d . Mixed l i q u o r i s then r o u t e d t o two BIOREACTORS (2) SCREENING & GRIT REMOVAL DISTN CHAMBER PC's (2) DISTN CHAMBER (30") SC's (2) DISTN CHAMBER RAS (24") WAS (18") TO HEAD OF PLANT PRIMARY DIGESTOR SECONDARY DIGESTOR CI to H I LAND APPLN F I G U R E 4 . 2 7 - G R I M S B Y P L A N T F L O W S H E E T ( E X I S T I N G ) GARAGE/ BOILER ROOM PUMPING STATION GRIT REMOVAL • DISTN CHAMBER SUBSTATION PC's BIOREACTORS o o o o 0 0 o o •CD DISTN CHAMBER RAS PUMPS SECONDARY CLARIFIERS APPROXIMATE SCALE - 1:1000 I N) U l I F I G U R E 4 . 3 8 - G R I M S B Y P L A N T T A Y O U T ( E X I S T I N G ) - 216 -secondary c l a r i f i e r s . Secondary e f f l u e n t i s c h l o r i n a t e d and then d i s c h a r g e d t o Lake O n t a r i o . S e t t l e d a c t i v a t e d sludge i s r e t u r n e d t o t h e d i s t r i b u t i o n chamber upstream of the b i o r e a c t o r s u s i n g two 30 HP screw pumps. The pumps are exposed t o the atmosphere and hence, permit DO entrainment of the sludge. Sludge i s a l s o wasted t o the primary c l a r i f i e r s w i t h these pumps. Combined primary and secondary sludges are pumped t o 3 two 4535 m d i g e s t o r s . Digested sludge i s a p p l i e d t o a g r i c u l t u r a l l a n d w i t h d i g e s t o r supernatant b e i n g r e t u r n e d t o the head o f the p l a n t . Waste p i c k l e l i q u o r i s added t o the secondary process f o r phosphorus removal. A f e r r o u s c h l o r i d e s o l u t i o n , c o n t a i n i n g approximately 8 pe r c e n t i r o n by weight, i s used. OME standards f o r the p l a n t e f f l u e n t based on monthly averages, are as f o l l o w s : BOD 5 - 15 mg/L TSS - 15 mg/L TP - 1.0 mg/L-P Composition of the i n f l u e n t sewage based on 1985/86 averages, i s as f o l l o w s : - 217 -BOD 5 - 123 mg/L TSS - 14 0 mg/L TKN - 22.4 mg/L TP - 5.1 mg/L T - 16° C Performance of the p l a n t has been good, w i t h the f o l l o w i n g average e f f l u e n t c o n c e n t r a t i o n s achieved d u r i n g 1985 and 1986: BOD 5 - 12.8 mg/L TSS - 7.1 mg/L TKN - 1.9 mg/L TP - 0.54 mg/L Monthly e f f l u e n t c o n c e n t r a t i o n averages f o r 1985 and 1986 were not obta i n e d . However, the O n t a r i o M i n i s t r y o f the Environment (1987), r e p o r t s t h a t the p l a n t exceeded i t s monthly BOD 5 o b j e c t i v e once i n 1985. TSS and TP o b j e c t i v e s were never exceeded. The e f f l u e n t data i n d i c a t e s t h a t n i t r i f i c a t i o n occurs i n t h e p l a n t on a year-round b a s i s . T h i s i s not s u r p r i s i n g , g i v e n the h i g h b i o r e a c t o r DO c o n c e n t r a t i o n s (6.8 mg/L) i n 1985 and 1986. - 218 -The p l a n t i s operated by the R e g i o n a l M u n i c i p a l i t y of N i a g a r a . An o n s i t e l a b o r a t o r y i s p r e s e n t i n which a l l Bio-P r e l a t e d a n a l y s e s , w i t h the e x c e p t i o n of N0 3, are r o u t i n e l y performed. I t was noted d u r i n g the v i s i t t o the p l a n t t h a t a h i g h BOD wastewater from a l o c a l winery i s t r u c k e d t o the p l a n t p e r i o d i c a l l y . T h i s i s added t o the primary d i g e s t o r , as e x p e r i e n c e has showed t h a t the a d d i t i o n of t h i s waste t o the mainstream pr o c e s s causes problems i n the b i o r e a c t o r . T h i s c o u l d be s i g n i f i c a n t f o r a Bio-P process, as winery wastewaters are l a r g e l y composed of fe r m e n t a t i o n products and hence, should c o n t a i n h i g h c o n c e n t r a t i o n of VFA's. These wastes c o u l d be s t o r e d o n s i t e and added t o the b i o r e a c t o r i n s m a l l q u a n t i t i e s . The composition and c o n s i s t e n c y of supply of these wastes, would have t o be e v a l u a t e d p r i o r t o committing t o such an o p t i o n however. 4.6.2 R e t r o f i t M o d i f i c a t i o n s The r e t r o f i t of the Baker Road P o l l u t i o n C o n t r o l P l a n t r e q u i r e s s i g n i f i c a n t m o d i f i c a t i o n s t o the e x i s t i n g o p e r a t i o n . As shown i n F i g u r e s 4.29 and 4.30, the f o l l o w i n g f o u r major m o d i f i c a t i o n s would be r e q u i r e d : - 219 -i ) I n s t a l l a g r a v i t y t h i c k e n e r f o r primary sludge f e r m e n t a t i o n . i i ) Modify the b i o r e a c t o r s t o accommodate p l u g flow c o n d i t i o n s and a n o x i c / a n a e r o b i c / a e r o b i c sequences. i i i ) Replace the e x i s t i n g RAS screw pumps wit h submersible pumps. iv) Route WAS d i r e c t l y t o the d i g e s t o r s and i n s t a l l f a c i l i t i e s f o r the lime treatment o f the d i g e s t o r supernatant. F u r t h e r study i n t o the use of the winery wastes as a VFA supply c o u l d e l i m i n a t e the need f o r primary sludge f e r m e n t a t i o n . However, f o r the purposes o f t h i s study, i t was assumed t h a t a fermenter would be r e q u i r e d . A t h i c k e n e r was s e l e c t e d over a completely mixed fermenter as i t would permit the use o f an a n o x i c / a n a e r o b i c / a e r o b i c process i n the b i o r e a c t o r . As shown i n F i g u r e 4.30, the t h i c k e n e r would be l o c a t e d south o f the e x i s t i n g primary c l a r i f i e r s . The e x i s t i n g primary c l a r i f i e r underflow pumps were found t o be adequate f o r the supply o f primary sludge t o the t h i c k e n e r . P i p i n g between the t h i c k e n e r and the primary c l a r i f i e r s and b i o r e a c t o r s , would be BIOREACTORS (2) SCREENING & GRIT REMOVAL DENOTES BIO-P MODIFICATION to to o F I G U R E 4 . 2 9 - G R I M S B Y R E T R O F I T F L O W S H E E T DENOTES BIO-P , APPROXIMATE SCALE - 1:1000 GARAGE/ SUBSTATION MODIFICATION BOILER ROOM F I G U R E 4 . 3 0 - G R I M S B Y R E T R O F I T L A Y O U T - 222 run underground. A pumphouse would be i n s t a l l e d t o house the t h i c k e n e r supernatant, r e c y c l e and wastage pumps. The waste l i n e from the t h i c k e n e r would be t i e d i n t o the e x i s t i n g 8 i n c h l i n e f e e d i n g the d i g e s t o r s . The second major m o d i f i c a t i o n would i n v o l v e m o d i f y i n g the b i o r e a c t o r s to accommodate a n o x i c / a n a e r o b i c / a e r o b i c sequences. Anoxic zones are r e q u i r e d as c a l c u l a t i o n s show t h a t n i t r i f i c a t i o n should occur a t a 6.5 day SRT and a wastewater temperature of 16°C. The a n o x i c / a n a e r o b i c / a e r o b i c sequence p r o v i d e s f o r d e n i t r i f i c a t i o n as w e l l as p e r m i t t i n g simple c o n v e r s i o n to an a n a e r o b i c / a e r o b i c process d u r i n g p e r i o d s when n i t r i f i c a t i o n does not occur. F i g u r e 4.31 p r e s e n t s a l a y o u t of the proposed r e t r o f i t t e d b i o r e a c t o r . As shown, h a l f of each r e a c t o r would be c o n v e r t e d to p l u g flow c o n d i t i o n s and compartmentalized. E x i s t i n g mechanical a e r a t o r s and t h e i r a s s o c i a t e d supports would be removed, c o n c r e t e d i v i d e r s would be c o n s t r u c t e d and mixers i n s t a l l e d i n the non-aerated and p o t e n t i a l l y non-aerated zones. A t o t a l o f s i x p o t e n t i a l l y non-aerated c e l l s , h a v i n g nominal HRT's o f 0.48 hours each, would be c r e a t e d . C e l l s 1 and 2 would be e x c l u -s i v e l y non-aerated and would be equipped with mixers. C e l l s 3 to 6 would be e i t h e r a e r a t e d or non-aerated depending upon the occurrence of n i t r i f i c a t i o n . They would be equipped w i t h 24.4 TO SC's e CM e 4 • 3 d 5 • FERMENTER SUPERNATANT 6 • TO SC's 1 FROM & PC's CELL STATUS HRT (HRS) 1,2 UNAERATED 0 .48 3,4 UNAERATED/ 0 .48 AERATED 5,6 AERATED 0 .48 7 AERATED 2 .9 o -• -MIXER TURBORATOR EXISTING AERATOR to to to F I G U R E 4 . 3 1 - G R I M S B Y R E T R O F I T B I O R E A C T O R L A Y O U T - 224 -a e r a t i o n d e v i c e s s i m i l a r t o those known as T u r b o r a t o r s (see F i g u r e 4.32). These c o n s i s t o f an open i m p e l l o r a t t a c h e d t o a hol l o w s h a f t . When the s h a f t i s open t o the atmosphere, the r o t a t i o n o f the i m p e l l o r draws a i r down the s h a f t and i n t o the wastewater. When the end of the s h a f t i s c l o s e d , the T u r b o r a t o r f u n c t i o n s as a mixer. T h e r e f o r e , u s i n g t h i s d e v i c e , c e l l s can e a s i l y be s h i f t e d between aer a t e d and non-aerated c o n d i t i o n s . The remaining h a l f of each r e a c t o r would c o n t i n u e t o operate as a completely mixed c e l l u s i n g the e x i s t i n g mechanical a e r a t o r s . Automatic DO c o n t r o l would be p r o v i d e d through a feedback loop which would a u t o m a t i c a l l y a d j u s t the h e i g h t o f the e f f l u e n t w e i r and hence, a u t o m a t i c a l l y a d j u s t the submergence of the a e r a t o r b l a d e s . DO probes, a process c o n t r o l l e r and an a c t u a t o r f o r the weir h e i g h t a d j u s t e r s would be p r o v i d e d . DO c o n t r o l f o r the T u r b o r a t o r s would not be p r o v i d e d as they would p r o v i d e o n l y a f r a c t i o n of the t o t a l oxygen requirement. Other m o d i f i c a t i o n s t o the b i o r e a c t o r s i n c l u d e the i n s t a l l a t i o n o f ORP probes and r e c o r d e r s , and the e x t e n s i o n of the e x i s t i n g 30 i n c h feed l i n e from the c e n t e r o f each r e a c t o r t o the c e n t e r o f C e l l 1. The t h i r d major m o d i f i c a t i o n t o the p l a n t would i n v o l v e r e p l a c i n g the e x i s t i n g RAS screw pumps w i t h submersible pumps t o prevent the a i r entrainment o f the RAS. Submersible pumps would - 225 -Standard " C " or " D " TEFC flanged motors. Quill shaft supported by heavy duty bearings for minimal vertical loading on motor. Mounting hinge permitting field access to impeller for routine main-tenance and cleaning. Heavy wall hollow shaft with adjustable length when used with a V-Belt drive. Patented impeller draws air down the shaft, shears it and disperses it radially while simultaneously mixing the liquid phase. COURTESY TURBORATOR TECHNOLOGY INC. FIGURE 4.32 - TURBORATOR SCHEMATIC - 226 -be l o c a t e d i n the e x i s t i n g screw pump sumps. The pumps would be equipped w i t h v a r i a b l e frequency c o n t r o l l e r s such t h a t the RAS pumping r a t e can be v a r i e d . The pumps would a l s o be used f o r sludge wasting and would t h e r e f o r e be designed t o produce s u f f i c i e n t head t o pump i n t o the d i g e s t o r s . P i p i n g would be i n s t a l l e d t o t i e - i n the submersible pumps' w i t h the e x i s t i n g 24 i n c h RAS and 18 i n c h WAS l i n e s . The f o u r t h and f i n a l major m o d i f i c a t i o n would i n v o l v e the r e - r o u t i n g of the WAS t o the d i g e s t o r s and the subsequent lime treatment of the d i g e s t o r supernatant t o p r e c i p i t a t e r e l e a s e d phosphorus. R e - r o u t i n g of the WAS t o the d i g e s t o r would i n v o l v e extending the e x i s t i n g 18 i n c h WAS l i n e underground t o the d i g e s t o r s . Lime a d d i t i o n f a c i l i t i e s would be l o c a t e d west of the e x i s t i n g g r i t chamber. Lime sludge would be pumped t o the secondary d i g e s t o r and hence, would u l t i m a t e l y be d i s p o s e d v i a l a n d a p p l i c a t i o n . The impact of low s o l i d s c o n c e n t r a t i o n WAS (assumed t o be 7000 mg/L) on the d i g e s t o r SRT was assessed. C a l c u l a t i o n s showed t h a t a 28 day SRT i n both the primary and secondary d i g e s t o r s would be maintained. T h i s was deemed adequate f o r sludge s t a b i l i z a t i o n . - 227 -The impact of lime sludge a d d i t i o n t o the secondary d i g e s t o r was assessed w i t h r e s p e c t t o d i g e s t o r performance, and a c c e p t a b i l i t y o f the f i n a l sludge f o r l a n d a p p l i c a t i o n . S i n c e t h e primary o b j e c t i v e of the secondary d i g e s t o r i n a two-stage d i g e s t i o n p r o c e s s i s s o l i d s s e p a r a t i o n ( M e t c a l f and Eddy, 1979), the a d d i t i o n of lime sludge should i f anything, impove d i g e s t o r performance. The use of the combined l i m e / a n a e r o b i c sludge was a l s o deemed a c c e p t a b l e f o r l a n d a p p l i c a t i o n . In f a c t , the a d d i t i o n o f lime may improve the market f o r the sludge, as the O n t a r i o M i n i s t r i e s of A g r i c u l t u r e and Food, the Environment and H e a l t h (1986) note t h a t lime-based sewage sludges can be a p p l i e d t o s o i l s o f lower pH than those t o which c o n v e n t i o n a l sewage sludges can be a p p l i e d t o . T h i s i s because the h i g h e r pH of the lime sludge r e s t r i c t s s o l u b i l i z a t i o n of metals i n the sludge. T h e r e f o r e , i t was concluded t h a t the a d d i t i o n of lime sludge t o the secondary d i g e s t o r would not cause any problems w i t h r e s p e c t t o d i g e s t o r performance or l a n d a p p l i c a t i o n of the d i g e s t e d sludge. Because of the above f o u r m o d i f i c a t i o n s , i t was f e l t t h a t a d d i t i o n a l s t a f f would be r e q u i r e d t o operate and m a i n t a i n the Baker Road p l a n t should i t be c o n v e r t e d t o Bio-P removal. Given the requirements f o r o p e r a t i o n and maintenance of the fermenter, the lime treatment f a c i l i t i e s , the DO and ORP probes and the new RAS pumps, combined wi t h the requirement f o r n i t r a t e a n a l y s i s i n the l a b o r a t o r y , i t was f e l t t h a t one a d d i t i o n a l s t a f f member would be r e q u i r e d . - 228 -A comparison of the o p e r a t i n g parameters f o r a Bio-P removal f a c i l i t y , w i t h those of the e x i s t i n g f a c i l i t y o p e r a t i n g a t d e s i g n c a p a c i t y , i s presented i n Tab l e 4.18. As shown i n t h i s t a b l e , Bio-P removal would r e s u l t i n reduced p i c k l e l i q u o r and power consumption, oxygen demand and sludge p r o d u c t i o n . The a d d i t i o n o f s m a l l q u a n t i t i e s o f p i c k l e l i q u o r (approximately 15 mg/L) would be r e q u i r e d i n a Bio-P o p e r a t i o n i n o r d e r t o reduce s o l u b l e phosphorus c o n c e n t r a t i o n s such t h a t the r e q u i r e d e f f l u e n t TP c o n c e n t r a t i o n can be achieved. S i g n i f i c a n t l y reduced power consumption would be r e a l i z e d as a r e s u l t o f the replacement of the s u r f a c e a e r a t o r s with the T u r b o r a t o r s . I t i s f e l t t h a t the s u r f a c e a e r a t o r s were o v e r s i z e d as evidenced by the h i g h DO c o n c e n t r a t i o n s p r e s e n t l y e x i s t i n g i n the b i o r e a c t o r s . T a b l e 4.18 a l s o shows t h a t Bio-P removal would r e s u l t i n i n c r e a s e d lime consumption and o p e r a t i o n s s t a f f i n g . 4.6.3 Cost A n a l y s i s A summary of the incremental c a p i t a l c o s t s a s s o c i a t e d w i t h Bio-P removal i s presented i n Table 4.19. As shown, the t o t a l i n c r e m e n t a l c o s t i s estimated t o be $1,061,000. A summary of the i n c r e m e n t a l o p e r a t i n g c o s t s i s presented i n Tab l e 4.20. Because o f the a d d i t i o n a l s t a f f i n g requirement, Bio-P removal a c t u a l l y r e s u l t s i n an i n c r e a s e o f $24,000 i n o p e r a t i n g c o s t s . PARAMETER BIO-P CASE CHEMICAL P CASE P i c k l e L i q u o r Consumption (kg/d) 272 1,732 Sludge P r o d u c t i o n - Mass (kg/d) 1,685 1,895 - Volume (m3/d) 29.5 38 Lime (kg/d) 387 Oxygen Demand1* (kg/d) 2,724 2,912 Incremental Power Consumption (kw) - +4 4 Incremental Operations S t a f f 1 TABLE 4.18 - GRIMSBY OPERATIONS COMPARISON 2. Based on the occurrence of n i t r i f i c a t i o n . Based on an i n f l u e n t flow of 4,550 m /d. TOTAL, MODIFICATION MATERIAL BULK INSTALLS! ITEM SPECIFICATION OUANTITV COST INSTALLATION FACTOR COST <*> MANHOURS <*> 1. FERMENTER MECHANICAL 10.5 M DIAM, 3.5 M SUD, 2.5 k U 1 65000 1.84 121*92 2. FERMENTER TANK CONCRETE 48 H3 13200 456 27600 EXCAVATION 304 M3 61 1885 3. SUPERNATANT PUMPS 5.2 L/s, 20 M TDH, 1.5 k U 2 4000 3.8 15504 4. SUPERNATANT PIPING 100 MM ASTM A53 100 M 1O410 447 24475 S. SUPNT PUMP INSTN AS PER FIGURE 3.2 1 54O0 44 6872 6. RECVCLE PUMPS 5.2 L/s, 15 n TDH, 1.1 kU 2 40O0 3.8 15504 T. RECVCLE INSTN AS PER FIGURE 3.2 1 5400 44 6872 8. PUMPHOUSE 6.1 M M 4.6 M 28 M2 12066 8. UASTAOE PUMPS 5.2 L/s, 15 H TOH, 1.1 k U 2 4000 3.8 15504 10.UASTAOE INSTN AS PER FIG. 3.2 1 5400 44 6872 11.UASTAOE PIPING 150 MM DIAM, U/G 100 M 13130 483 28366 EXCAVATION/BACKFILL 30 M3 12 372 1. COMPARTMENTALIZATION CONRETE PARTITIONS 132 M3 36300 1254 75900 2. ORP PROBES 4 4000 2.1 8568 3. ORP RECORDERS 2 700 2. 1 1499 4. MIXERS 0.37 k U 8 10200 1.34 13941 5. AERATORS DISMANTLE 4 288 8928 6. TURBORATORS 3.7 k U 8 56000 1.8 102816 7. DO OONTROL 4 LOOP CONTROLLER 1 5000 177 10587 DO PROBES 4 14000 2. 1 29988 VALUE ACTUATORS 4 11600 72 14064 8. PIPINO HODS 750 MM DIAM 20 M 9160 183 15016 1. NEU PUMPS 212 L/s, 16 M TDH, 53 kU 2 30000 3.8 116280 1. STORAOE SILOS STEEL U / EPOXV LINER, 24 M3 1 5462 3.2 17828 2. CHEMICAL FEEDER ROTARV TVPE, 96 k g / h r 1 5167 1.23 6483 3. MIX TANK STEEL, 0.16 M3 1 484 6 2962 4. NIX TANK MIXER 0.055 kU 1 904 1.34 1236 S. HOLDING TANK FD PUMPS 0.44 L/s, 6.0 M TDH, 0.04 k U 2 2800 3.8 10853 6. HOLDING TANK 76 M3 1 19952 3.2 65123 7. HOLDING TANK MIXER 0.3 k U 1 1275 1.34 1743 8. HOLDING TANK PUMPS 0.44 L/s, 3.0 M TDH, 0.02 kU 2 2800 3.8 10853 10.RAPID HIX/FLOCCN TNK 0.27 M3 1 648 6 3966 11.RAPID MIX MIXER 0.010 kU 1 904 1.34 1236 12.FL0CCN MIXER 0.001 kU 1 904 1.34 1236 13.CLARIFIER MECHANICAL 2.1 M D, 1.0 kU 1 27800 1.9 53876 14.LIME SLUDOE PUMPS 0.079 L/s, 10.0 M TDH, 0.015 k 2 2800 3.8 10853 15.BUILDING 12 M M 15 M 180 M2 77400 SUB-TOTAL 947117 ENGINEERING 113654 VFA SUPPLV BIOREACTOR RAS PUMPS LIME TREATMENT OF DIGESTOR SUPERNATANT CO o TOTAL 1060771 TABLE 4.19 - GRIMSBY CAPITAL COST SUMMARY - 231 -ITEM 1. P i c k l e L i q u o r 2. Sludge D i s p o s a l 3. Power 4. L i n e 5. Op e r a t i o n s S t a f f 6. Maintenance M a t e r i a l s TOTAL INCREMENTAL ANNUAL COST ($12,000) (16,000) (6,000) 12,000 42,000 4,000 £24^000 TABLE 4.20 - GRIMSBY OPERATING COST SUMMARY - 232 -T h e r e f o r e , t h e r e i s no r e t u r n on the c a p i t a l investment. Even i f the requirement f o r a d d i t i o n a l o p e r a t i n g s t a f f was waived, an annual s a v i n g s of o n l y $18,000 would be r e a l i z e d . T h i s would amount t o a simple payback p e r i o d of 59 y e a r s ; c l e a r l y a poor p r o p o s i t i o n . 4.7 M i l t o n Water P o l l u t i o n C o n t r o l P l a n t 4.7.1 P l a n t D e s c r i p t i o n The town of M i l t o n i s l o c a t e d n o r t h of the C i t y of B u r l i n g t o n i n the R e g i o n a l M u n i c i p a l i t y of H a l t o n i n c e n t r a l O n t a r i o . The M i l t o n Water P o l l u t i o n C o n t r o l P l a n t was o r i g i n a l l y c o n s t r u c t e d i n 1949 and has been expanded f o u r times t o accommodate growth of the town. The p l a n t c u r r e n t l y serves a p o p u l a t i o n o f approximately 28,000 people. The p l a n t uses the a c t i v a t e d sludge p r o c e s s and c o n t a i n s s c r e e n i n g , g r i t removal, primary sedimentation, d i f f u s e d a i r and mechanical a e r a t i o n , secondary sedimentation, c h l o r i n a t i o n / d e c h l o r i n a t i o n , chemical phosphorus removal, e f f l u e n t f i l t r a t i o n and both a e r o b i c and a n a e r o b i c d i g e s t i o n . Flowsheets and l a y o u t drawings f o r the e x i s t i n g f a c i l i t y are p r e s e n t e d i n F i g u r e s 4.33 and 4.34, r e s p e c t i v e l y . PLANT 'A' ALUM (TYP) INFLUENT TREATED EFFLUENT LAND APPLN to w F I G U R E 4.33 - M I L T O N P L A N T F L O W S H E E T ( E X I S T I N G ) F I G U R E 4.34 - M I L T O N P L A N T L A Y O U T ( E X I S T I N G ! - 235 -As shown i n the drawings, the primary and secondary f a c i l i t i e s c o n s i s t o f f o u r separate t r a i n s ( P l a n t s 'A', 'B', 'C and 'D'). P l a n t s "A', 'B' and ' C use coarse bubble d i f f u s e d a i r systems whereas P l a n t 'D' uses d r a f t - t u b e mechanical a e r a t o r s . Rotary blowers supply the a i r f o r P l a n t 'A', 'B' and ' C . Design c a p a c i t i e s o f the i n d i v i d u a l p l a n t s , based on average d a i l y flow, are as f o l l o w s : P l a n t 'A7 P l a n t 'B' P l a n t ' C P l a n t 'D' TOTAL 500 m 3/d 2,727 m 3/d 1,818 m 3/d 7.865 m 3/d 12,910 m 3/d The p l a n t d i s c h a r g e s t r e a t e d e f f l u e n t t o S i x t e e n M i l e Creek which runs adjacent t o the p l a n t . Because of the s e n s i t i v e nature o f t h i s creek, the O n t a r i o M i n i s t r y o f the Environment has s e t the f o l l o w i n g e f f l u e n t c r i t e r i a f o r the p l a n t : BOD 5 - 4.2 mg/L (55 kg/d) SP - 0.43 mg/L-P (5.5 kg/d) NH_ - 90% removal Two-stage anaerobic d i g e s t i o n i s used f o r primary sludge s t a b i l i z a t i o n . WAS i s th i c k e n e d , a e r o b i c a l l y d i g e s t e d and then t h i c k e n e d a g a i n p r i o r t o f i n a l d i s p o s a l . Both sludges are - 236 -then d i s p o s e d v i a l a n d a p p l i c a t i o n u s i n g a p r i v a t e l y c o n t r a c t e d tank t r u c k f i r m . Sludge s t a b i l i z a t i o n and h a n d l i n g f a c i l i t i e s a r e c e n t r a l i z e d ( i . e . they are not s p l i t i n t o t r a i n s as are the primary and secondary treatment f a c i l i t i e s ) . L i q u i d alum i s c u r r e n t l y used f o r phosphorus removal. C u r r e n t l y an e q u i v a l e n t dosage o f 108 mg/L of dry alum i s added t o a l l a e r a t i o n b a s i n s from a c e n t r a l f a c i l i t y . I n f l u e n t t o the p l a n t i s t y p i c a l o f Canadian m u n i c i p a l i t i e s . Average c o n s t i t u e n t v a l u e s (based on 1985/86 monthly averages) f o r the raw sewage are as f o l l o w s : B0D 5 - 210 mg/L SS - 193 mg/L TP { - 8 . 8 mg/L-P SP - 3.8 mg/L-P TKN - 33.9 mg/L-N NH 3 - 24.3 mg/L-N NC> - 0.13 mg/L-N I t was assumed t h a t the minimum temperature o f the wastewater was 12°C f o r d e s i g n purposes. Performance o f the p l a n t has been reasonable w i t h the f o l l o w i n g average c o n s t i t u e n t v a l u e s and compliance r e s u l t s a c h i e v e d d u r i n g 1985 and 1986: - 237 -Average E f f l u e n t C o n c e n t r a t i o n Monthly Compliance Parameter (mq/L) (Maximum 24) BOD c 3.0 21 ss 2.5 N/A TP .62 N/A SP .18 23 TKN 1.2 N/A NH 3 .58 22 N0 3/N0 2 16.4 N/A The p l a n t i s operated by the Regional M u n i c i p a l i t y o f H a l t o n . An o n s i t e l a b o r a t o r y i s a v a i l a b l e i n which a l l Bio-P r e l a t e d a n a l y s e s are r o u t i n e l y performed. 4.7.2 R e t r o f i t M o d i f i c a t i o n s R e v i s e d flowsheets and l a y o u t drawings f o r the M i l t o n Water P o l l u t i o n C o n t r o l P l a n t are pre s e n t e d i n F i g u r e s 4.35 and 4.36, r e s p e c t i v e l y . Layout drawings of the b i o r e a c t o r s f o r P l a n t s 'A', 'B', 'C and 'D' are pr e s e n t e d i n F i g u r e 4.37. INFLUENT SCREENING & GRIT REMOVAL DENOTES BIO-P MODIFICATION PLANT 'A' ALUM (TYP) PLANT 'B' PLANT "C PLANT 'D' FERMENTER c i TREATED EFFLUENT EFFLUENT FILTRATION LIME TO HEAD OF PLANT \ / I Y '-I JL J" WAS THICKENER AEROBIC DIGESTOR WAS THICKENER PRIMARY DIGESTOR SECONDARY DIGESTOR TO HEAD OF PLANT to u 00 , LAND APPLN F I G U R E 4.35 - M I L T O N R E T R O F I T F L O W S H E E T FIGURE 4.36 - MILTON RETROFIT LAYOUT PLANT ' A ' T 0 s c . s -3 1 vl/ FROM P C ' s 9 .0 n TO S C ' s o *o 4X-F O-'pOir PLANT ' C FROM P C ' s 7.6 in TO SC's 1 -tx}-o -=> C-o - 3 o FROM P C ' s 2 6 . 5 • • • o 2 * 13 .4 m to *» o O - MIXER • - TURBORATOR FROM P C ' s FERMENTER SUPNT F I G U R E 4 .37 - M I L T O N R E T R O F I T B I O R E A C T O R L A Y O U T - 241 -As shown i n F i g u r e 4.35, the f o l l o w i n g t h r e e major m o d i f i c a t i o n s would, be r e q u i r e d t o r e t r o f i t the M i l t o n p l a n t f o r Bio-P removal: i ) P r o v i d e primary sludge f e r m e n t a t i o n f a c i l i t i e s . i i ) Modify the b i o r e a c t o r s t o accommodate the r e q u i r e d anaerobic, anoxic and a e r o b i c zones. i i i ) P r o v i d e f a c i l i t i e s f o r the lime treatment of the a e r o b i c d i g e s t o r supernatant. The i n s t a l l a t i o n of a new g r a v i t y t h i c k e n e r was s e l e c t e d f o r primary sludge fe r m e n t a t i o n . The use of the WAS t h i c k e n e r s was c o n s i d e r e d as a low c o s t o p t i o n however, the l o s s use o f the p r e - d i g e s t o r t h i c k e n e r would r e s u l t i n the o v e r l o a d i n g of the d i g e s t o r . S i m i l a r l y , the use of the p o s t - d i g e s t o r t h i c k e n e r would r e s u l t i n l a r g e i n c r e a s e s i n s t a b i l i z e d sludge volumes. The c o n v e r s i o n of the secondary an a e r o b i c d i g e s t o r t o a fermenter was a l s o c o n s i d e r e d . However, the i n c r e a s e i n sludge volumes r e s u l t i n g from t h i s was not f e l t t o be j u s t i f i a b l e . - 242 -New primary c l a r i f i e r underflow pumps would be r e q u i r e d f o r a Bio-P r e t r o f i t . The e x i s t i n g raw sludge pump l o c a t e d i n the d i g e s t o r b u i l d i n g does not have s u f f i c i e n t c a p a c i t y t o pump a t a flow r a t e o f 5% of the p l a n t i n f l u e n t . New fermenter supernatant, r e c y c l e and wastage pumps would a l s o be r e q u i r e d . Because of the l a c k o f space a v a i l a b l e , the fermenter would be l o c a t e d a t the south end of the p l a n t a d j a c e n t t o the P l a n t 'D' a e r a t i o n tanks. T h i s would n e c e s s i t a t e l o n g p i p i n g runs f o r the raw sludge feed, the supernatant d i s t r i b u t i o n and the wastage t o the ana e r o b i c d i g e s t o r s . P i p i n g would be run underground i n tr e n c h e s as t u n n e l s are not p r e s e n t i n the M i l t o n p l a n t . A pumphouse adj a c e n t t o the fermenter would have t o be c o n s t r u c t e d t o house the supernatant, r e c y c l e and wastage pumps. The new primary c l a r i f i e r underflow pumps would be l o c a t e d i n the d i g e s t o r b u i l d i n g . C o n s i d e r a b l e changes t o the b i o r e a c t o r s would be r e q u i r e d t o c r e a t e the r e q u i r e d anaerobic, anoxic and a e r o b i c zones. S i m i l a r t o the oth e r p l a n t s , i t was determined t h a t the o p t i m a l c o n f i g u r a t i o n would be an a n o x i c / a n a e r o b i c / a e r o b i c sequence. With the e x c e p t i o n o f P l a n t 'A', s i g n i f i c a n t q u a n t i t i e s o f c o n c r e t e were r e q u i r e d t o p r o v i d e the r e q u i r e d degree of com p a r t m e n t a l i z a t i o n . - 243 -E x t e n s i o n s t o the a i r supply p i p i n g would be r e q u i r e d i n P l a n t s 'B' and ' C t o supply a i r t o the a e r o b i c compartments.' A new a e r a t i o n system would be p r o v i d e d f o r P l a n t 'D' as the e x i s t i n g mechanical a e r a t o r s are p h y s i c a l l y too l a r g e f o r the r e v i s e d b i o r e a c t o r . A system employing T u r b o r a t o r s would be used i n s t e a d . Automatic DO c o n t r o l would be p r o v i d e d f o r each p l a n t as i t was not p r e s e n t i n the e x i s t i n g f a c i l i t y . DO c o n t r o l f o r P l a n t s 'A', 'B' and ' C would be achieved through the placement of a flow c o n t r o l v a l v e on a vent p i p e o f f o f the a i r supply header. DO c o n t r o l f o r P l a n t 'D' would be p r o v i d e d through the use of v a r i a b l e frequency c o n t r o l l e r s on the T u r b o r a t o r d r i v e r s . ORP m o n i t o r i n g would a l s o be i n s t a l l e d i n a l l f o u r b i o r e a c t o r s . In an attempt t o minimize r e t r o f i t c o s t s , the o p e r a t i o n o f the b i o r e a c t o r s as a s e r i e s of completely mixed r e a c t o r s was c o n s i d e r e d (e.g. b i o r e a c t o r 'A' would serve as an a n o x i c zone, b i o r e a c t o r 'B' would serve as an a naerobic zone, e t c . ) . However, because of h y d r a u l i c and p i p i n g d i f f i c u l t i e s , t h i s was deemed t o be i m p r a c t i c a l . I t was determined t h a t the continued use of a e r o b i c d i g e s t i o n , combined w i t h lime treatment of the supernatant, would be the b e s t method f o r WAS h a n d l i n g as i t maximizes the use o f e x i s t i n g f a c i l i t i e s and a l l o w s f o r the c o n t i n u e d use of l a n d a p p l i c a t i o n f o r f i n a l d i s p o s a l . - 244 -F a c i l i t i e s f o r the lime treatment of the d i g e s t o r supernatant would be l o c a t e d n o r t h of the e x i s t i n g WAS t h i c k e n i n g tanks. Lime sludge would be pumped from the c l a r i f i e r back t o the second WAS t h i c k e n e r from where i t would be pumped t o the sludge l o a d i n g f a c i l i t y f o r u l t i m a t e d i s p o s a l . As p r e v i o u s l y noted i n S e c t i o n 4.6, i t i s not a n t i c i p a t e d t h a t the a d d i t i o n of the lime sludge t o the a e r o b i c sludge would c r e a t e d i f f i c u l t i e s w i t h r e s p e c t t o d i g e s t o r o p e r a t i o n and/or l a n d a p p l i c a t i o n . The impacts of these m o d i f i c a t i o n s on the o p e r a t i o n o f the p l a n t are summarized i n Table 4.21. As shown i n t h i s t a b l e , the Bio-P r e t r o f i t would r e s u l t i n reduced alum consumption, oxygen demand, methane p r o d u c t i o n and sludge p r o d u c t i o n . I ncreases i n power and lime consumption would a l s o be r e a l i z e d . I t should be noted t h a t the a d d i t i o n of a s m a l l q u a n t i t y o f alum (25 mg/L) would be r e q u i r e d t o remove phosphorus t o the s p e c i f i e d l e v e l of 0.43 mg/L-SP. The presence of the fermenter, the lime treatment f a c i l i t i e s , DO c o n t r o l and ORP i n s t r u m e n t a t i o n , and the a d d i t i o n a l chemical a n a l y s i s requirements would n e c e s s i t a t e an i n c r e a s e i n o p e r a t i o n s and maintenance s t a f f . For M i l t o n i t was assumed t h a t one a d d i t i o n a l f u l l - t i m e person would be r e q u i r e d . - 245 -4.7.3 Cost A n a l y s i s A summary of the inc r e m e n t a l c a p i t a l c o s t s a s s o c i a t e d w i t h Bio-P removal i s presented i n Tab l e 4.22. As shown, the t o t a l i n c remental c a p i t a l c o s t f o r the Bio-P r e t r o f i t i s approximately $1,260,000. A summary of the incremental o p e r a t i n g c o s t s f o r Bio-P removal i s presented i n Table 4.34. As i n d i c a t e d , the c o n v e r s i o n o f the M i l t o n p l a n t t o Bio-P removal would r e s u l t i n an annual s a v i n g s of $42,000. Based on these c o s t s , the simple payback p e r i o d f o r the c a p i t a l investment i s 3 0 y e a r s . T h e r e f o r e , t h e r e i s no r a t e o f r e t u r n on the investment f o r p r o j e c t l i v e s o f 5, 10, 15 and 20 y e a r s . - 246 -PARAMETER 1. Alum Consumption (kg/d) 2. Lime Consumption (kg/d) 3. Sludge P r o d u c t i o n - Mass (kg/d) 3 - Volume (m /d) BIO-P CASE CHEMICAL P CASE 323 1,394 153 1,610 38 2,287 49 4. Oxygen Demand (kg/d) 4,688 4,783 5. Methane P r o d u c t i o n (m /d) 3 53 446 6. Incremental Power * Consumption (kw) +4.6 0 TABLE 4.21 - MILTON OPERATIONS COMPARISON 1. I n c l u d e s power sav i n g s from reduced oxygen demand. MODIFICATION ITEM SPECIFICATION QUANTITY MATERIAL TOTAL . INSTALLEI 1. UFA SUPPLV 2. BIOREACTOR 1. PC UNDERFLOW PUMPS 2. PC UNDERFLOW PI PI NO 3- PC PI PINO EXCAVATION 4. PC INSTRUMENTATION 5. FERMENTER MECHANICAL 6. FERMENTER TANK T. SUPERNATANT PUMPS B. SUPERNATANT PIPINO 9. SUPNT PI PINO EXCUN 10.SUPNT INSTRUMENTATION 11. RECVCLE PUMPS 12. RECVCLE INSTN 13. UASTE PUMPS 1A.UASTE PUMP PIPINO 15. UASTE PI PINO EXCUN 16. UASTE PUMP INSTN IT.PUMPHOUSE 1. COHPARTMKNTALIZATION 2. DO PROBES 3. DO CONTROL INSTN A. 00 CONTROL PANEL 5. ORP PROBES 6. ORP RECORDERS 7. MIXERS 7.5 L / s , 16.O M TDH, l.OkU 150 HH ASTM AS3 AS PER FIO. 3.2 B.B M DIAM, 3.5 CONCRETE EXCAVATION 3.7 L / s , 20.0 H TDH 100 HH ASTM A53 M SUD, 2.lkU .8 kU AS PER FIO. 3.2 3.7 L / s , 15.0 H TDH, .8 kU AS PER FIO. 3.2 3.7 L / s , 15 M TDH, 0.8 kU 150 MM ASTM A53 AS PER FIO. 3.2 6.1 M M 4.6M CONRETE PARTITIONS as p»r Section 3.3 PLANT A PLANT B PLANT C 0.18 kU 0.24 KU 0.24 kU 8. AERATION PIPING 9. PLANT D AERATION LIME TREATMENT 1. OF DIOESTOR 2. SUPERNATANT 3. 4. 5. 6. 7. 8. STORAGE SILO FEEDER 6 SLURRV MIX SVSTEH HOLDING TANK HOLOINO TANK PUMPS RAPID MIX/ FLOCCLN CLARIFIER LIME SLUDOE PUMPS BUILDING PLANT D - 0.55 kU PLANT B - 100 MM PLANT C - 150 MM DISMANTLE SURFACE AEARATORS 1.5 kU TURBORATORS 5.0 kU TURBORATORS STEEL U/ EPOXV LINER, 9.6 M3 DRV FEEDER, MIX TANK, MIXER ft DISTRIBUTION PUMPS <38 kg LIME/ hr> STEEL U/ EPOXV LINER <30M3> 0.175 L / s , 3.0 M TDH, O.OlkU STEEL TANK UN MIXERS 2.0 M DIAM 0.031 L / s , 10 M TDH 14.5 H M 11.5 M M 7.0 M 2 100 M 300 M3 1 1 40 M3 255 M3 2 300 M 675 M3 1 2 1 2 100 M 300 M3 1 28 M2 301 MS 8 3 M 8 4 4 10 8 16 80 M 60 M 4 2 ' 5 1 1 1 2 1 1 2 167 M2 COST INSTALLATION BULK COST <*> MANHOURS FACTOR <s> 4290 3.8 16628 13130 403 28366 60 I860 5400 44 6872 58000 1.84 108854 11000 380 23000 51 1581 3764 3.8 14589 31230 1341 73426 135 4185 5400 44 6672 3764 3.8 14589 5400 44 6872 3764 3.6 14589 13130 483 28366 60 1860 5400 44 6872 12040 82775 2660 173075 28000 2.1 59976 18700 448 32962 7500 1.96 14994 8000 2. 1 17136 1400 2. 1 2999 4004 2 8168 ' 10952 2 ' 22343 8762 2 17874 26228 2 53505 5873 464 20374 5057 291 14179 288 6928 140OO 1.6 25704 4S000 1.8 82620 3130 17 3723 34204 26 35694 8400 2.6 23990 458 4.05 1892 8538 9 8961 40328 320 51055 458 4.05 1892 71610 SUB-TOTAL 1125296 ENGINEERING 135035 to TOTAL 1260331 TABLE 4 . 22 - MILTON CAPITAL COST SUMMARY - 248 -ITEM 1. Alum 2. Sludge D i s p o s a l 3. Lime 4. Power 5. Operations S t a f f 6. Maintenance M a t e r i a l s TOTAL TABLE 4.23 - MILTON INCREMENTAL ANNUAL COST ($73,000) (22,000) 5, 000 1,000 42,000 5,000 OPERATING COST SUMMARY - 249 -4.8 E l m i r a Water P o l l u t i o n C o n t r o l P l a n t 4.8.1 P l a n t D e s c r i p t i o n The town of E l m i r a i s l o c a t e d i n southwestern O n t a r i o , approximately 20 km n o r t h of K itchener-Waterloo. The E l m i r a Water P o l l u t i o n C o n t r o l P l a n t c u r r e n t l y t r e a t s domestic sewage from a p o p u l a t i o n o f approximately 7,100 people, as w e l l as a wastewater d i s c h a r g e from the U n i r o y a l Chemical D i v i s i o n P l a n t 3 l o c a t e d i n the town. Design c a p a c i t y of the p l a n t i s 4,550 m /d based on average d a i l y flow. The p l a n t i s l i s t e d as a c o n v e n t i o n a l a c t i v a t e d sludge p l a n t but because of i t s long SRT (approximately 50 days) , o p e rates as an extended a e r a t i o n p l a n t . The p l a n t c o n t a i n s flow e q u a l i z a t i o n , g r i t removal, primary sedimentation, d i f f u s e d a i r a e r a t i o n , mechanical a e r a t i o n , secondary sedimentation, f i l t e r p r e s s i n g , chemical phosphorus removal and f i l t e r p r e s s i n g u n i t o p e r a t i o n s . A flowsheet of the e x i s t i n g p l a n t i s presented i n F i g u r e 4.38. As shown i n F i g u r e 4.38, the p l a n t e s s e n t i a l l y c o n s i s t s of two independent p l a n t s w i t h i n one. A f t e r p a s s i n g through flow e q u a l i z a t i o n , g r i t removal and primary c l a r i f i c a t i o n , the domestic sewage i s s p l i t i n t o two streams. One t h i r d of the flow i s mixed w i t h one t h i r d of the U n i r o y a l flow ( f o r a combined flow SCREENINC FLOW EQUALIZATION DOMESTIC INFLUENT INDUSTRIAL INFLUENT GRIT REMOVAL PC's (2) NEW BIOREACTORS (2) I OLD BIOREACTOR SC's (2) FILTERS V Fe SC CI TREATED EFFLUENT LIME + TO FLOW FERRIC CHLORIDE EQUALIZATION RAW SLUDGE STORAGE WAS STORAGE CHEMICAL CONDITIONING FILTER PRESSES to o TO LANDFILL F I G U R E 4 . 3 8 - E L M I R A P L A N T F L O W S H E E T ( E X I S T I N G ) - 251 -of 1,517 m /d) and i s routed t o the " o l d " b i o r e a c t o r where a e r a t i o n i s p r o v i d e d w i t h mechanical s u r f a c e a e r a t o r s i n comp l e t e l y mixed r e a c t o r s . The remaining two t h i r d s o f the domestic sewage and U n i r o y a l streams (combined flow o f 3,033 3 m /d) are ro u t e d t o the "new" b i o r e a c t o r s . These r e a c t o r s operate i n a p l u g - f l o w mode and use f i v e r o t a r y blowers t o supply d i f f u s e d a i r f o r a e r a t i o n purposes. F e r r i c c h l o r i d e (waste p i c k l e l i q u o r ) i s added t o the b i o r e a c t o r e f f l u e n t f o r phosphorus removal, p r i o r t o secondary sedimentation. The e f f l u e n t from the secondary c l a r i f i e r s i s f i l t e r e d i n an automatic backwash f i l t e r , c h l o r i n a t e d and then d i s c h a r g e d t o Canagigue Creek. When the p l a n t was f i r s t operated, a n a e r o b i c d i g e s t i o n of the primary and waste a c t i v a t e d sludges was used f o r sludge s t a b i l i z a t i o n . However, c o n s i s t e n t d i g e s t o r performance c o u l d not be maintained due t o the i n d u s t r i a l component of the wastewater. As a r e s u l t , a chemical c o n d i t i o n i n g and f i l t e r p r e s s o p e r a t i o n was i n s t a l l e d . Primary and waste a c t i v a t e d sludges a re now rout e d t o the primary and secondary d i g e s t o r s , r e s p e c t i v e l y , f o r s t o r a g e purposes o n l y . They are then mixed and c o n d i t i o n e d w i t h f e r r i c c h l o r i d e and lime p r i o r t o f i l t e r p r e s s i n g . F i l t e r cake (approximately 35% s o l i d s by weight) i s hauled t o a l o c a l l a n d f i l l f o r d i s p o s a l . F i l t e r p r e s s f i l t r a t e i s r e t u r n e d t o the e q u a l i z a t i o n b a s i n . O n t a r i o M i n i s t r y o f the Environment standards f o r the p l a n t e f f l u e n t (based on monthly averages) are as f o l l o w s : - 252 -BOD 5 - 7.5 mg/L TSS - 15.0 mg/L TP - 1.0 mg/L-P TKN - 3.5 mg/L-N NH 3 - 7.5 mg/L-N pH - 6 . 5 - 8 . 5 ( A p r i l through October) (November through March) Average v a l u e s f o r the c o n s t i t u e n t s i n the domestic sewage (based on May 1985 t o March 1987 averages) are as f o l l o w s : BOD 5 - 153 mg/L TSS - 202 mg/L TKN - 42 mg/L-N TP - 8.6 mg/L-P Average v a l u e s f o r the c o n s t i t u e n t s i n the U n i r o y a l e f f l u e n t (based on May 1985 t o March 1987 averages) are as f o l l o w s : B0D 5 - 650 mg/L TSS - 168 mg/L TKN - 93 mg/L-N TP - 4.8 mg/L-P - 253 -Because the U n i r o y a l e f f l u e n t i s added t o the primary e f f l u e n t , i t was necessary t o c a l c u l a t e average primary e f f l u e n t c h a r a c t e r i s t i c s . These are as f o l l o w s : BOD 5 - 189 mg/L TSS - 125 mg/L TKN - 48 mg/L-N TP - 7.5 mg/L-P Tmax - 21° C Tmin - 8°C I t should be noted t h a t U n i r o y a l i s r e q u i r e d t o add a l k a l i n i t y t o i t s wastewater when ammonia c o n c e n t r a t i o n s i n the combined flow t o the E l m i r a p l a n t exceed 3 0 mg/L and/or when the pH o f the U n i r o y a l e f f l u e n t i s l e s s than 8.0. T h i s i s t o b u f f e r a c i d p r o d u c t i o n d u r i n g n i t r i f i c a t i o n . Performance of the p l a n t has not been good wi t h the f o l l o w i n g average e f f l u e n t c o n c e n t r a t i o n s and compliance r e s u l t s a c h i e v e d f o r the p e r i o d o f May 1985 t o March 1987: Average E f f l u e n t C o n c e n t r a t i o n Monthly Compliances Parameter (mg/L) (Maximum 23) 6.3 19 TSS 16.5 13 TKN 7.2 14 TP 1.5 8 - 254 -F a c t o r s i n f l u e n c i n g t h i s performance i n c l u d e the i n d u s t r i a l wastewater and the f a c t t h a t the p l a n t i s o p e r a t i n g v e r y c l o s e t o i t s d e s i g n c a p a c i t y . The p l a n t i s operated by the O n t a r i o M i n i s t r y o f the Environment. Four f u l l - t i m e o p e r a t o r s are employed. The p l a n t has an o n s i t e l a b o r a t o r y equipped t o perform a l l Bio-P r e l a t e d a n a l y s e s w i t h the e x c e p t i o n o f BOD5, N0 3 and VFA's. BOD 5 and N0 3 a n a l y s i s i s c u r r e n t l y c a r r i e d out a t the OME l a b o r a t o r y i n Toronto. VFA's are not analyzed f o r the E l m i r a p l a n t . 4.8.2 R e t r o f i t M o d i f i c a t i o n s R e t r o f i t flowsheets and l a y o u t drawings o f the r e t r o f i t t e d b i o r e a c t o r s are presented i n F i g u r e s 4.39 and 4.40, r e s p e c t i v e l y . As shown i n these drawings, o n l y two major m o d i f i c a t i o n s would be r e q u i r e d t o r e t r o f i t the p l a n t f o r Bio-P removal. The f i r s t would i n v o l v e c o n v e r t i n g the e x i s t i n g primary d i g e s t o r t o a fermenter t o produce VFA's. The approach used i s s l i g h t l y d i f f e r e n t than t h a t proposed f o r the p r e v i o u s p l a n t s . The d i g e s t o r would e s s e n t i a l l y be used as a g r a v i t y t h i c k e n e r . Primary sludge would be allowed t o s e t t l e and ferment and V F A - r i c h supernatant would be pumped o f f the top of the tank t o the b i o r e a c t o r s . SRT c o n t r o l would be p r o v i d e d through the GRIT DOMESTIC INFLUENT SCREENING FLOW EQUALIZATION REMOVAL p c ' s <2> N E " B I 0 R E A C T 0 R S ( 2 ) INDUSTRIAL INFLUENT X I I I I • I -I—I L ' r—>- - -I SC'S (2) FILTERS OLD BIOREACTOR Fe SC'S (2 ) CI TREATED EFFLUENT DENOTES BIO-P MODIFICATION U l U l LIME + TO FLOW . FERRIC CHLORIDE EQUALIZATION FERMENTER WAS STORACE TO LANDFILL CHEMICAL CONDITIONING FILTER PRESSES F I G U R E 4.39 - E L M I R A R E T R O F I T F L O W S H E E T NEW BIOREACTOR 4 * 2.5 m »•—4«—•*—«*—H*-42.4 m FROM PC's 2 f O FERMENTER SUPERNATANT o O O MIXER MECHANICAL AERATOR • TURBORATOR TO SC's s CM oo m o * OLD BIOREACTOR 8 r . as o • e -• FERMENTER SUPERNATANT 2 * 9.1 - 18.2 m TO SC's TO SC's to U l F I G U R E 4.40 - E L M I R A R E T R O F I T B I O R E A C T O R L A Y O U T S - 257 -i n s t a l l a t i o n o f r e c y c l e pumps and c o n t r o l l e d wasting u s i n g the e x i s t i n g pumps. VFA e l u t r i a t i o n would be p r o v i d e d by r e c y c l i n g the t h i c k e n e d sludge and the i n s t a l l a t i o n o f a slow speed mixer a t t he base o f the tank. T h e r e f o r e , a c o n v e n t i o n a l t h i c k e n i n g o p e r a t i o n i s not p r o v i d e d . I t should be noted t h a t r e p a i r s t o the r o o f o f the tank would be r e q u i r e d p r i o r t o i t s use. In a d d i t i o n , new primary c l a r i f i e r underflow pumps would be r e q u i r e d such t h a t flow r a t e s up t o 5 percent o f the p l a n t i n f l u e n t flow can be pumped t o the fermenter. The second m o d i f i c a t i o n would i n v o l v e c r e a t i n g the r e q u i r e d anaerobic, anoxic and a e r o b i c c o n d i t i o n s i n the b i o r e a c t o r . Again, an a n o x i c / a n a e r o b i c / a e r o b i c sequence was proposed i n o r d e r t o minimize c o s t s . Conversion of the new r e a c t o r s t o t h i s p rocess would be r e l a t i v e l y easy. Anaerobic and a e r o b i c compartments would be c r e a t e d and mixers i n s t a l l e d i n these zones. M o d i f i c a t i o n s t o the a i r supply p i p i n g would be r e q u i r e d , such t h a t the a i r supply t o the ana e r o b i c and anoxic zones c o u l d be i s o l a t e d from the r e s t o f the zones. Automatic DO c o n t r o l and ORP m o n i t o r i n g would be i n s t a l l e d . Automatic DO c o n t r o l would be p r o v i d e d by u t i l i z i n g a feedback loop w i t h DO probes, a s i n g l e l oop process c o n t r o l l e r and a vent v a l v e on the a i r s u p p l y header. - 258 -Conversion o f the o l d r e a c t o r s would i n v o l v e more expense due t o t h e i r completely-mixed o p e r a t i o n . As shown i n F i g u r e 4.40, the e x i s t i n g mechanical s u r f a c e a e r a t o r s would be removed from two c e l l s , and p l u g - f l o w c o n d i t i o n s would be c r e a t e d i n t h e s e c e l l s , through the c o n s t r u c t i o n o f d i v i d i n g w a l l s . M i x e rs would be i n s t a l l e d i n the anaerobic and ano x i c zones and T u r b o r a t o r s would be p r o v i d e d f o r the a e r a t e d zones. Wastewater would e x i t these c e l l s t o the two remaining c e l l s equipped w i t h the mechanical a e r a t o r s . Automatic DO c o n t r o l would be p r o v i d e d w i t h a feedback loop from DO probes t o a v a r i a b l e frequency c o n t r o l l e r which would v a r y the speed of the T u r b o r a t o r motors. T o t a l DO c o n t r o l would not be achieved as i t was not deemed f e a s i b l e t o attempt t o c o n t r o l both the T u r b o r a t o r s and the mechanical a e r a t o r s . ORP m o n i t o r i n g would a l s o be p r o v i d e d i n the a n a e r o b i c and anoxic zones. M o d i f i c a t i o n s t o the sludge h a n d l i n g o p e r a t i o n s were not deemed necessary. Phosphorus r e l e a s e d u r i n g WAS storage would be negated by the a d d i t i o n o f f e r r i c c h l o r i d e and lime f o r sludge c o n d i t i o n i n g . I t was f e l t t h a t the e x i s t i n g o p e r a t i o n s s t a f f i n g was adequate f o r a Bio-P f a c i l i t y . Some a d d i t i o n a l maintenance time may be r e q u i r e d f o r DO and ORP probe c l e a n i n g . In a d d i t i o n , o n s i t e VFA a n a l y s i s would be r e q u i r e d . However, i t was f e l t t h a t these o p e r a t i o n s c o u l d be accomodated by the e x i s t i n g s t a f f . - 259 -A comparison o f the o p e r a t i n g parameters f o r a Bio-P removal f a c i l i t y w i t h those f o r the e x i s t i n g chemical removal f a c i l i t y a re p r e s e n t e d i n Table 4.24. As shown i n t h i s t a b l e , Bio-P removal r e s u l t s i n reduced f e r r i c c h l o r i d e and power consumption and m a r g i n a l l y i n c r e a s e d sludge p r o d u c t i o n . Sludge mass i s a c t u a l l y reduced but, because of the fermenter o p e r a t i o n , primary sludge s o l i d s c o n c e n t r a t i o n s w i l l be l e s s than i n the e x i s t i n g o p e r a t i o n , and hence, sludge volumes w i l l i n c r e a s e . Power consumption i s reduced as a r e s u l t of d e n i t r i f i c a t i o n . I t should be noted t h a t f e r r i c c h l o r i d e a d d i t i o n (10 mg/L) w i l l be r e q u i r e d t o reduce s o l u b l e phosphorus c o n c e n t r a t i o n s i n order t o achieve the e f f l u e n t TP standard. The main concern a s s o c i a t e d w i t h a Bio-P removal r e t r o f i t , i s the impact of the U n i r o y a l wastewater on the growth of fermenting and Bio-P b a c t e r i a . No allowance has been made f o r t h i s i n p r e p a r i n g the r e t r o f i t d e s i g n s , however, p r e v i o u s problems w i t h anaerobic d i g e s t i o n and g e n e r a l p l a n t performance i n d i c a t e the p o t e n t i a l f o r growth i n h i b i t i o n . T h e r e f o r e , l a b or p i l o t s c a l e s t u d i e s would be r e q u i r e d t o v a l i d a t e the t e c h n i c a l f e a s i b i l i t y o f both primary sludge f e r m e n t a t i o n and the Bio-P p r o c e s s . - 260 -PARAMETER BIO-P CASE CHEMICAL P CASE 1. FeCl., Consumption (kg/d) 44 137 758 899 60 59 3. Dewatered Sludge 3 P r o d u c t i o n (m /d) 7.2 7.1 4. Oxygen Demand (kg/d) 2,577 2,895 5. Incremental Power Consumption (kw) - +5.8 6. Incremental Operations S t a f f TABLE 4.24 - ELMIRA OPERATIONS COMPARISON2' 1. Undewatered sludge. 2. Based on an i n f l u e n t flow of 4,550 m /d. 2. Sludge P r o d u c t i o n - Mass (kg/d) 3 - Volume (m /d) TOTAL MATERIAL BULK INSTALLED MODIFICATION ITEM SPECIFICATION QUANTITV COST INSTALLATION FACTOR COST C»> MANHOURS <•> UFA 1. REPAIRS TO TANK SUPPLV 2. SUPERNATANT PUMPS 1.3 L / S , 20 N TDH, 0.4 kU 2 3764 3. SUPERNATANT PIPI NO 100 M M ASTM A53 100 H 1O410 447 4. PUMP INSTN AS PER FIOURE 3.2 2 10800 86 5. RECVCLE PUMPS 2.3 L / s , IT n TDH, 0.5S k U 2 3764 6. PC UNDERFLOW PUMPS 2.3 L / s , 21 M TDH, 0.7 kU 2 3764 7. PIPING EXCAVATION EXCAUATE/BACKFILL 270 H3 108 6. FERMENTER MIXER O.A k U 1275 BIO- 1. COMPARTMENTALIZATION CONRETE PARTITIONS 72 H3 18800 684 REACTOR 2. ORP PROBES A 4000 3. ORP RECORDERS 2 700 A. MIXERS 0.20 k U 12 15300 S. AIR PIPING MODS 100 H H ASTM AS3 50 H 5205 224 EXISTING PIPING MOOS 200 6. DO PROBES 6 28000 r. PROCESS CONTROLLER 2 - 1 LOOP CONTROLLERS 2 4000 71 VARIABLE FREQUENCV 1 2000 71 s. TURBORATORS 3.7 k U 6 42000 SUB-TOTAL ENGINEERING 15000 3.8 14588 24475 13744 3.8 14588 3.8 14588 3348 1.34 1743 41400 2. 1 8568 2. 1 1498 1.34 20912 12238 6200 2. 1 59976 6281 4241 1.8 77112 340SO5 to 0> 40861 TOTAL 381365 TABLE 4.25 - ELMIRA CAPITAL COST SUMMARY - 262 -ITEM F e r r i c C h l o r i d e Sludge D i s p o s a l Power Maintenance M a t e r i a l s TOTAL INCREMENTAL ANNUAL COST ($8,000) 0 (900) 1,600 1^7^3001 TABLE 4.26 - ELMIRA OPERATING COST SUMMARY - 263 -4.8.3 Cost A n a l y s i s A summary of the incremental c a p i t a l c o s t s a s s o c i a t e d w i t h Bio-P removal i s presented i n T a b l e 4.25. As shown, the t o t a l i n c r e m e n t a l c a p i t a l c o s t i s $381,000. A summary of the i n c r e m e n t a l o p e r a t i n g c o s t s i s p r e s e n t e d i n T a b l e 4.26. Annual s a v i n g s o f approximately $7,300 would be r e a l i z e d through the use of Bio-P removal. Based on these e s t i m a t e s , the simple payback p e r i o d f o r the c a p i t a l investment i s 52 y e a r s . T h e r e f o r e , t h e r e i s no r a t e o f r e t u r n on the c a p i t a l investment f o r p r o j e c t l i v e s o f 5, 10, 15 and 20 y e a r s . 4.9 W e l l e s l e y Water P o l l u t i o n C o n t r o l P l a n t 4.9.1 P l a n t D e s c r i p t i o n The v i l l a g e of W e l l e s l e y i s l o c a t e d i n southwestern O n t a r i o , approximately 20 km west of Kitchener-Waterloo. The W e l l e s l e y Water P o l l u t i o n C o n t r o l P l a n t c u r r e n t l y s e r v e s a p o p u l a t i o n of approximately 1,000 people, and has a design 3 c a p a c i t y o f 500 m /d. - 264 -The p l a n t i s a packaged extended a e r a t i o n p l a n t and c o n t a i n s s c r e e n i n g , d i f f u s e d a i r a e r a t i o n and c h l o r i n a t i o n u n i t o p e r a t i o n s . The p l a n t can a l s o be operated as a c o n t a c t s t a b i l i z a t i o n p l a n t . A combined f l o w s h e e t / l a y o u t drawing o f the p l a n t i s pr e s e n t e d i n F i g u r e 4.41. As shown i n F i g u r e 4.41, a f t e r p a s s i n g through the scre e n s , the raw sewage e n t e r s a mixing zone where i t i s mixed w i t h RAS from the c l a r i f i e r . RAS i s s u p p l i e d by a s i n g l e a i r l i f t pump. The sewage i s then aerated, s e t t l e d and c h l o r i n a t e d . A i r i s s u p p l i e d by t h r e e r o t a r y blowers. Alum i s added t o the a e r a t i o n b a s i n f o r phosphorus removal. Sludge i s wasted from the a e r a t i o n b a s i n t o a h o l d i n g tank, w i t h an a i r l i f t pump. The sludge i s allowed t o co n c e n t r a t e t o roughly 5 per c e n t s o l i d s and i s then hauled away by a vacuum t r u c k and a p p l i e d t o a g r i c u l t u r a l l a n d . Because the p l a n t operates a t a long SRT (approximately 40 days) the requirement f o r d i g e s t i o n p r i o r t o l a n d a p p l i c a t i o n has been waived. T r e a t e d e f f l u e n t i s d i s c h a r g e d t o the N i t h R i v e r . O n t a r i o M i n i s t r y o f the Environment standards f o r the p l a n t e f f l u e n t a re as f o l l o w s : TREATED F I G U R E 4 . 4 1 - WFrTfT-ggT.lgv P L A N T F L O W S H E E T / L A Y O U T ( E X I S T I N G ) - 266 -BOD 5 - 15.0 mg/L TSS - 15.0 mg/L TP - 1.0 mg/L-P I n f l u e n t c h a r a c t e r i s t i c s (based on 1985/86 monthly averages) a re as f o l l o w s : BOD 5 - 150 mg/L TSS - 160 mg/L TKN - 28.4 mg/L NH 3 - 15.0 mg/L TP - 5.5 mg/L Tmax - 18"C Tmin - 7°C Performance o f the p l a n t has been f a i r w i t h the f o l l o w i n g average c o n s t i t u e n t v a l u e s and compliance r e s u l t s a c h i e v e d d u r i n g 1985 and 1986: Average E f f l u e n t C o n c e n t r a t i o n Monthly Compliances Parameter (mg/L) (Maximum 24) B0D c 4.2 24 TSS 12.6 18 TP 0.9 21 NH 3 <0.2 N/A NO- 22.6 N/A - 267 -As shown by the above data, n i t r i f i c a t i o n occurs year-round. T h i s i s not s u r p r i s i n g , g i v e n the l o n g SRT. The p l a n t i s operated by the O n t a r i o M i n i s t r y of the Environment. The p l a n t i s s t a f f e d by a p a r t - t i m e o p e r a t o r , who devotes approximately f o u r hours per day t o the o p e r a t i o n o f the W e l l e s l e y p l a n t . An o n s i t e l a b o r a t o r y i s p r e s e n t where TSS and c h l o r i n e r e s i d u a l are analyzed. A n a l y s i s f o r a l l oth e r c o n s t i t u e n t s are performed a t M i n i s t r y o f the Environment l a b o r a t o r i e s i n Waterloo o r Toronto. 4.9.2 R e t r o f i t M o d i f i c a t i o n s A r e v i s e d f l o w s h e e t / l a y o u t f o r the p l a n t i s rep r e s e n t e d i n F i g u r e 4.42. Because of the nature of the p l a n t l a y o u t , the approach taken f o r the d e s i g n was d i f f e r e n t than f o r the other p l a n t s . S i n c e the p l a n t does not have a primary c l a r i f i e r , VFA's would be produced by u s i n g the f i r s t t h i r d o f the r e a c t o r as a f e r m e n t a t i o n zone. The a i r supply t o t h i s zone would be shut o f f and a mixer i n s t a l l e d t o keep the s o l i d s i n the f r o n t - h a l f o f t h i s zone i n suspension. The second h a l f o f t h i s zone would not be mixed and hence, s o l i d s would be allowed t o s e t t l e out. A submersible pump would be i n s t a l l e d near the end of t h i s unmixed s e c t i o n t o pump s o l i d s back t o the mixed s e c t i o n . p PI P2 Z l Z2 Z3 Z4 Z5 Z6 Z7 Z8 Z9 AIR LIFT PUMP MIXED LIQUOR RECYCLE FERMENTATION RECYCLE MIXING ZONE CLARIFIER SLUDGE HOLDING CHLORINE CONTACT FERMENTATION ANAEROBIC ANOXIC ANOXIC AEROBIC SLUDGE TO LAND APPLN TREATED EFFLUENT INFLUENT ALUM LIME TANK DIAMETER - 13.7 m to 00 O - MIXER DENOTES BIO-P MODIFICATION APPROXIMATE SCALE - 1:100 F I G U R E 4.42 - W R T . T . R S L E Y R E T R O F I T F L O W S H E E T / L A Y O U T - 269 -T h i s would a s s i s t i n m a i n t a i n i n g a fermenting b a c t e r i a p o p u l a t i o n and would ensure a c o n s i s t e n t VFA supply. The p l a n t SRT would be maintained a t 40 days such t h a t l a n d a p p l i c a t i o n o f the sludge c o u l d be cont i n u e d . As a r e s u l t , n i t r i f i c a t i o n would c o n t i n u e t o occur year-round and d e n i t r i f i c a -t i o n o f the RAS would be r e q u i r e d . T h e r e f o r e , i t i s proposed t o operate the b i o r e a c t o r u s i n g an a n a e r o b i c / a n o x i c / a e r o b i c sequence s i m i l a r t o the UBC p i l o t p l a n t . T h i s would r e q u i r e r o u t i n g the RAS t o the anoxic zone u s i n g the e x i s t i n g a i r l i f t pump. A submersible pump would be i n s t a l l e d near the end of the anoxic zone t o the pump d e n i t r i f i e d mixed l i q u o r back t o the head of the anae r o b i c zone. Anaerobic and anoxic c o n d i t i o n s would be c r e a t e d by s h u t t i n g o f f the a i r supply t o these s e c t i o n s of the tank and i n s t a l l i n g a mixer. Automatic DO c o n t r o l would be p r o v i d e d by c r e a t i n g a feedback loop w i t h a DO probe l o c a t e d i n the a e r o b i c zone, a s i n g l e l oop process c o n t r o l l e r and a flow c o n t r o l v a l v e l o c a t e d on a vent l i n e from the a i r supply header. ORP would a l s o be measured i n the anaerobic zone and recorded on . a c h a r t r e c o r d e r . A v a r i a b l e frequency c o n t r o l l e r would a l s o be i n s t a l l e d such t h a t the output o f the fermented s o l i d s r e c y c l e and mixed l i q u o r r e c y c l e pumps c o u l d be v a r i e d . - 270 -CASE 1. Alum Consumption (kg/d) 7.3 30 2. Lime Consumption (kg/d) 3.9 3 3. Sludge P r o d u c t i o n (m /d) 0.54 1.2 4. Oxygen Demand (kg/d) 5. Incremental Power Consumption (kw) +1.0 6. Incremental Operations S t a f f TABLE 4.27 - WELLESLEY OPERATIONS COMPARISON 1 , 3 1. Based on an i n f l u e n t flow of 500 m /d. - 271 -A comparison of the o p e r a t i n g parameters f o r a Bio-P removal f a c i l i t y v e r s u s those f o r the e x i s t i n g f a c i l i t y i s p r e s e n t e d i n Table 4.27. As shown, Bio-P removal r e s u l t s i n reduced alum consumption and sludge p r o d u c t i o n , but would r e q u i r e a d d i t i o n a l lime and power consumption. No i n c r e a s e s i n o p e r a t i o n s s t a f f i n g would be r e q u i r e d as the new f a c i l i t i e s r e q u i r e minimal amounts of maintenance. A d d i t i o n a l l a b o r a t o r y a n a l y s i s would be r e s t r i c t e d t o o c c a s i o n a l f e r m e n t a t i o n zone VFA measurements. T h i s would be done i n the M i n i s t r y o f Environment l a b o r a t o r i e s and hence, c o s t s would be minimal. I t should be noted t h a t a s m a l l q u a n t i t y of alum (15 mg/L) w i l l be r e q u i r e d t o reduce s o l u b l e phosphorus c o n c e n t r a t i o n s i n o r d e r t o achieve the e f f l u e n t TP standard. 4.9.3 Cost A n a l y s i s A summary of the incremental c a p i t a l c o s t s a s s o c i a t e d w i t h Bio-P removal i s presented i n Tab l e 4.28. As shown, the t o t a l i n c r e m e n t a l c a p i t a l c o s t f o r a Bio-P r e t r o f i t i s approximately $52,000. A summary of the i n c r e m e n t a l o p e r a t i n g c o s t s i s pre s e n t e d i n Tab l e 4.29. Annual sa v i n g s of approximately $2,100 would be r e a l i z e d through the use of Bio-P removal. TOTAL MATERIAL BULK INSTALLED MODIFICATION ITEM SPECIFICATION QUANTITV COST INSTALLATION FACTOR COST <*> MANHOURS <*> 1. UFA SUPPLV 2. BIOREACTOR 1. RECVCLE PUMPS 2. RECVCLE INSTN 1. COMPARTNENTALIZATION 2. ORP PROBES 9. ORP RECORDERS 4. MIXERS 5. DO PROBES 6. FLOU CONTROL VALUE 7. PROCESS CONTROLLER 8. ML RECVCLE PUMP 5.8 L / s , 7 M TDH, 0.56 k U VARIABLE SPEED CONTROLLER PRESSURE TREATED MOOD 0.50 O. 17 k U k U 100 H H DIAM 1 LOOP 5.8 L / s , 7 M TDH, 0.56 k U 1 1 100 H2 1 1 1 1 1 1 1 1 2500 2000 lOOO 350 1458 1275 3500 1800 2000 2500 71 14 71 3.8 2.1 2.1 1.34 1.34 2.1 3.8 8680 4241 2000 2142 750 1883 1743 7497 2270 4241 9690 SUB-TOTAL ENOINEERINO TOTAL 46256 5551 51807 M M TABLE 4 . 3 « - WKT.T.KSLEY CAPITAL COST SUMMARY - 273 -INCREMENTAL ITEM ANNUAL COST 1. Alum ($2,000) 2. Lime 130 3. Sludge D i s p o s a l (620) 4. Power 160 5. Maintenance M a t e r i a l s 200 TOTAL ($2,130 TABLE 4.29 - WELLESLEY OPERATING COST SUMMARY - 274 -Based on these e s t i m a t e s , the simple payback p e r i o d f o r the c a p i t a l investment i s 25 y e a r s . T h e r e f o r e , t h e r e i s no r e t u r n on the investment f o r p r o j e c t l i v e s o f 5, 10, 15 and 20 y e a r s . - 275 -5.0 DISCUSSION W i t h i n t h i s s e c t i o n , the r e s u l t s developed i n S e c t i o n 4.0 w i l l be analyzed. A g e n e r a l review of the r e s u l t s i s i n i t i a l l y p r e s e n t e d i n which the f e a s i b i l i t y o f Bio-P removal f o r the p l a n t s s t u d i e d i s d i s c u s s e d . Then, u s i n g t h i s g e n e r a l review as a b a s i s , the impacts of v a r i o u s parameters on the f e a s i b i l i t y of Bio-P removal are e v a l u a t e d . Parameters c o n s i d e r e d i n c l u d e chemical c o s t and a v a i l a b i l i t y , sewage c h a r a c t e r i s t i c s , p l a n t s i z e , p l a n t c o n f i g u r a t i o n , sludge p r o c e s s i n g t e c h n i q u e s , n u t r i e n t removal standards and p r o j e c t type ( i . e . new f a c i l i t y v e r s u s p l a n t r e t r o f i t ) . F o l l o w i n g the e v a l u a t i o n o f the impacts of these parameters, an o v e r a l l assessment on the p o t e n t i a l f o r the use o f Bio-P removal i n Canada i s made. F i n a l l y , f u t u r e r e s e a r c h needs are i d e n t i f i e d and d i s c u s s e d . 5.1 General Review of R e s u l t s A summary of the incremental c a p i t a l and o p e r a t i n g c o s t s , simple payback p e r i o d s and IRR's a s s o c i a t e d w i t h Bio-P removal f o r a l l n i n e p l a n t s s t u d i e d , i s presented i n T a b l e 5.1. As shown i n t h i s t a b l e , Bio-P removal o n l y o f f e r s r e t u r n on the c a p i t a l investment f o r the Calgary, Edmonton, Regina and Saskatoon p l a n t s , when p r o j e c t l i v e s of l e s s than 20 y e a r s are c o n s i d e r e d . No r e t u r n would be r e a l i z e d from the i n s t a l l a t i o n of Bio-P removal f a c i l i t i e s a t the remaining f i v e p l a n t s . INCREMENTAL COST ($ x 1Q 3) PLANT CAPITAL OPERATING PAYBACK PERIOD (years) 5 Y r s . IRR 10 Y r s . (%) 15 Y r s . 20 Y r s . 1. C a l g a r y 5,368 •1,490 3.6 13 .9 25.6 27.3 27.6 2 . Edmonton 4,261 2,002 2.1 41.0 46.5 46.9 47.0 3 . Regina 2,132 294 7.3 - 6.6 11.4 13.0 4. Saskatoon 2,258 270 8.4 - 3.7 8.7 10.5 5. Windsor E x i s t i n g New Combined 2,074 970 3,044 48 .43 91 43 23 33 - - --6. Grimsby 1,060 -24 - - - - -7. M i l t o n 1,260 42 30 - - - -8. E l m i r a 381 7.3 52 - - -9. W e l l e s l e y 52 2.1 25 - - - -TABLE 5.1 - BIO-P ECONOMIC SUMMARY FOR PLANTS STUDIED - 277 -The r a t e s o f r e t u r n are, however, v e r y a t t r a c t i v e f o r the f o u r p l a n t s i n which a r e t u r n would be achieved. T h i s i s e s p e c i a l l y t r u e f o r the C a l g a r y Bonnybrook and Edmonton Gold Bar p l a n t s . In C a l g a r y , where approximately $1.3 m i l l i o n was spent on alum i n 1986 and approximately $2.0 m i l l i o n per y e a r would be spent when o p e r a t i n g a t p l a n t d e s i g n c a p a c i t y , t h e r e i s i n c e n t i v e t o s e r i o u s l y c o n s i d e r a Bio-P r e t r o f i t . A l o g i c a l f i r s t s tep would be t o c a r r y out a number o f f u l l - s c a l e experiments a t the p l a n t . These c o u l d i n v o l v e the f o l l o w i n g : i ) M o n i t o r i n g of VFA c o n c e n t r a t i o n s i n the i n f l u e n t , primary e f f l u e n t and t h i c k e n e r supernatant. i i ) T e s t i n g the a b i l i t y of one of the e x i s t i n g g r a v i t y t h i c k e n e r s t o f u n c t i o n as a primary sludge fermenter. i i i ) I s o l a t i n g one of the o l d a e r a t i o n tanks (and i t ' s a s s o c i a t e d secondary c l a r i f i e r ) from the remainder of the p r o c e s s , and o p e r a t i n g i t i n an a n o x i c / a n a e r o b i c / a e r o b i c sequence. S i m i l a r l y , a t the Edmonton Gold Bar p l a n t , t h e r e i s a s i g n i f i c a n t economic i n c e n t i v e t o use Bio-P removal should phosphorus removal requirements be implemented. The a b i l i t y t o develop a Bio-P b a c t e r i a p o p u l a t i o n i n the r e a c t o r s has been - 278 -demonstrated through the f u l l - s c a l e t e s t performed a t the p l a n t ( S h i v j i , 1987) . I t i s f e l t t h a t the use of primary sludge f e r m e n t a t i o n should a l l e v i a t e some of the i n c o n s i s t e n t phosphorus removal e x p e r i e n c e d d u r i n g the t e s t . Work would have t o be done t o q u a n t i f y the amount of phosphorus r e l e a s e o c c u r r i n g under a n a e r o b i c d i g e s t i o n , should d i g e s t i o n be proposed f o r WAS s t a b i l i z a t i o n . The use of Bio-P removal i s a l s o v e r y a t t r a c t i v e f o r the Regina and Saskatoon p l a n t s , e s p e c i a l l y g i v e n t h a t both p l a n t s w i l l be expanded and/or upgraded over the next few y e a r s . A phased approach f o r implementing Bio-P removal would be a d v i s a b l e f o r these p l a n t s . Chemical phosphorus removal would be used i n i t i a l l y w h i l e the Bio-P process was o p t i m i z e d w i t h r e s p e c t t o fermenter o p e r a t i o n , anaerobic and anoxic zone s i z e s , e t c . The r e t r o f i t o f the f i v e O n t a r i o p l a n t s does not appear t o be e c o n o m i c a l l y v i a b l e . The low c o s t o f phosphorus removal chemicals a t Windsor, Grimsby and E l m i r a make Bio-P removal u n a t t r a c t i v e f o r these t h r e e p l a n t s . In a d d i t i o n , major m o d i f i c a t i o n s would be r e q u i r e d t o r e t r o f i t both the e x i s t i n g Windsor L i t t l e R i v e r p l a n t and the Grimsby p l a n t . S i m i l a r l y , the compl e x i t y o f a r e t r o f i t f o r the M i l t o n p l a n t r e s u l t s i n an e x c e s s i v e c a p i t a l c o s t r e l a t i v e t o the s a v i n g s i n o p e r a t i n g c o s t s . Although minimal m o d i f i c a t i o n s would be r e q u i r e d a t - 279 -the W e l l e s l e y p l a n t , the p l a n t i s o f such a s m a l l s i z e t h a t economies o f s c a l e make c a p i t a l investments v e r y hard t o j u s t i f y . 5.2 Chemical Cost and A v a i l a b i l i t y The c o s t of phosphorus removal chemicals has a major impact on the economic v i a b i l i t y o f Bio-P removal. In o r d e r t o assess t h i s impact, chemical c o s t s r e s u l t i n g i n a 4 p e r c e n t IRR, were c a l c u l a t e d f o r each p l a n t f o r p r o j e c t l i v e s o f 5, 10, 15 and 20 y e a r s . A 4 p e r c e n t IRR was s e l e c t e d s i n c e t h i s r e p r e s e n t s a reasonable r a t e of r e t u r n over and above i n f l a t i o n . Costs f o r both alum and i r o n (as opposed t o i r o n s a l t s ) were c a l c u l a t e d and are summarized i n T a b l e s 5.2 and 5.3 r e s p e c t i v e l y . T a b l e 5.2 i n d i c a t e s t h a t , even i n the event of s i g n i f i c a n t r e d u c t i o n s i n the p r i c e of alum, Bio-P removal would l i k e l y remain economic f o r the Calgary, Edmonton, Regina and Saskatoon p l a n t s . However, Table 5.2 a l s o shows t h a t alum p r i c e s would have t o i n c r e a s e s i g n i f i c a n t l y f o r Bio-P t o become e c o n o m i c a l l y v i a b l e f o r the O n t a r i o p l a n t s ( M i l t o n and W e l l e s l e y ) c u r r e n t l y u s i n g alum f o r phosphorus removal. The a v a i l a b i l i t y o f aluminum and i r o n based i n d u s t r i a l by-products a l s o has a s i g n i f i c a n t impact on the economics of Bio-P removal. Three of the p l a n t s s t u d i e d use i n d u s t r i a l by-- 280 -ALUM COST FOR 4% IRR ACTUAL ($/dry tonne) PLANT ALUM COST ($/tonne) 5 Y r s . 10 Y r s . 15 Y r s . 20 Yrs 1. C a l g a r y 215 182* 124* 105* 96* 2. Edmonton 215 126* 91* 79* 74* 3. Regina 215 282 202* 171* 160* 4. Saskatoon 215 313 217 185* 170* 5. Windsor 186 E x i s t i n g 723 394 286 233 - New 432 227 160* 127* - Combined 598 322 232 187 6. Grimsby 186 617 376 297 258 7. M i l t o n 186 790 470 365 313 8. E l m i r a 241 712 394 290 238* 9. W e l l e s l e y 241 1,367 744 540 439 TABLE 5.2 - SUMMARY OF ALUM COSTS REQUIRED  FOR A 4 PERCENT IRR * denotes cases where the r e q u i r e d chemical c o s t i s l e s s than the a c t u a l chemical c o s t - 281 -IRON COST FOR 4% IRR ($/tonne) PLANT 5 Y r s . 10 Y r s . 15 Y r s . 20 Yrs, 1. C a l g a r y 1,867 1,276 1, 081 987 2. Edmonton 1,281 922 804 746 3. Regina 2,861 2,017 1,729 1,592 4. Saskatoon 3,198 2,218 1,896 1,738 5. Windsor E x i s t i n g 7,420 4,043 2,932 2,388 New 4,414 2, 319 1, 630 1,293 Combined 6,128 3,302 2,373 1,917 6. Grimsby 6, 432 3,922 3 , 097 2 , 692 7. M i l t o n 8,133 4,839 3 ,755 3,224 8. E l m i r a 7,308 4, 045 2,972 2,446 9. W e l l e s l e y 13,835 7,536 5,463 4,448 TABLE 5.3 - SUMMARY OF IRON COSTS REQUIRED  FOR A 4 PERCENT IRR Note: C u r r e n t p r i c e of Ferrous C h l o r i d e i n O n t a r i o i s $495/tonne Fe Cur r e n t p r i c e o f F e r r i c C h l o r i d e i n O n t a r i o i s $1045/tonne Fe - 282 -p r o d u c t s f o r phosphorus removal. Windsor uses an aluminum based, spent c a t a l y s t w h i l e both Grimsby and E l m i r a use an i r o n based p i c k l e l i q u o r o r i g i n a t i n g from the s t e e l i n d u s t r y . The c o s t of these p r o d u c t s i s extremely low r e l a t i v e t o manufactured c h e m i c a l s . For example, the spent aluminum c a t a l y s t used a t the Windsor p l a n t c o s t s $23 per tonne or approximately $770 per tonne o f aluminum. The c o s t o f aluminum i n commercial alum i s approximately $2200 per tonne. S i m i l a r l y , the c o s t o f i r o n i n the f e r r o u s c h l o r i d e used a t Grimsby and the f e r r i c c h l o r i d e used a t E l m i r a i s $300 and $680 per tonne r e s p e c t i v e l y , whereas the c o s t o f i r o n i n commerical f e r r i c c h l o r i d e i s approximately $4400 per tonne (BASF, 1988). T h e r e f o r e , should the supply o f these by-products d i m i n i s h or should t h e i r use be r e s t r i c t e d , s i g n i f i c a n t o p e r a t i n g c o s t i n c r e a s e s c o u l d be r e a l i z e d by the p l a n t s u s i n g these by-products. Whether or not t h i s w i l l happen i s v e r y s p e c u l a t i v e , although the O n t a r i o M i n i s t r y of the Environment p l a n s t o i n v e s t i g a t e p o l l u t a n t s c o n t a i n e d i n i n d u s t r i a l by-products (Archer, 1988). The impact of the a v a i l a b i l i t y o f i n d u s t r i a l by-products on the economics o f Bio-P removal i s shown i n T a b l e s 5.2 and 5.3. T a b l e 5.2 shows t h a t Bio-P removal would become economic f o r the new Windsor p l a n t a t p r o j e c t l i v e s of 15 and 20 y e a r s , and f o r the E l m i r a p l a n t a t a p r o j e c t l i f e o f 20 y e a r s , i f alum was used i n p l a c e o f the e x i s t i n g chemicals. S i g n i f i c a n t i n c r e a s e s i n alum p r i c e s would be necessary t o make Bio-P economic a t Grimsby and the e x i s t i n g Windsor p l a n t , however. - 283 -Table 5.3 shows t h a t r e l a t i v e to the c u r r e n t p r i c e of i r o n i n O n t a r i o , Bio-P removal would be economic o n l y f o r the Edmonton p l a n t . While t h i s i s p u r e l y h y p o t h e t i c a l s i n c e low c o s t i r o n i s not a v a i l a b l e i n A l b e r t a , i t suggests t h a t the economic use of Bio-P removal i s u n l i k e l y i n O n t a r i o , g i v e n the c u r r e n t a v a i l a b i l i t y and c o s t of p i c k l e l i q u o r . 5.3 Sewage C h a r a c t e r i s t i c s As p r e v i o u s l y mentioned the carbon to phosphorus r a t i o i n the i n f l u e n t sewage s e t s a l i m i t on the amount of phosphorus which can be removed from the wastewater b i o l o g i c a l l y . For combined n i t r o g e n and phosphorus removal, the carbon to n i t r o g e n r a t i o i n the i n f l u e n t sewage i s a l s o important s i n c e i t s e t s a l i m i t on the d e n i t r i f i c a t i o n c a p a b i l i t y of the p r o c e s s . For the p l a n t s s t u d i e d , and indeed i n g e n e r a l i n Canada, t o t a l n i t r o g e n removal i s not a requirement and hence, the Bio-P p r o c e s s e s c o n s i d e r e d h e r e i n were designed to d e n i t r i f y the RAS o n l y , i n o r d e r t o p r e v e n t n i t r a t e s from e n t e r i n g the anaerobic zone. As a r e s u l t , no problems r e l a t e d to carbon a v a i l a b i l i t y f o r d e n i t r i f i c a t i o n were experienced. T h e r e f o r e , i t can be concluded t h a t i n g e n e r a l , the carbon to n i t r o g e n r a t i o s i n Canadian wastewaters should not a f f e c t the v i a b i l i t y of Bio-P removal. T h i s would not be the case however, i f t o t a l n i t r o g e n qremoval standards were implemented. - 284 -S i n c e i t was determined t h a t supplemental chemical a d d i t i o n would be r e q u i r e d i n a l l p l a n t s t o c o n s i s t e n t l y meet the e f f l u e n t phosphorus standards, i t can a l s o be p o s t u l a t e d t h a t Bio-P removal w i l l l i k e l y be l i m i t e d by a v a i l a b l e carbon f o r most Canadian m u n i c i p a l i t i e s . While the method of a n a l y s i s employed ( i . e . assuming a maximum phosphorus c o n c e n t r a t i o n i n the biomass) i s r e s p o n s i b l e f o r t h i s c o n c l u s i o n , a comparison of the B0D 5:P r a t i o s f o r the p l a n t s s t u d i e d (see Table 5.4) w i t h the minimum r a t i o s recommended by Evans and Crawford (1985) (see T a b l e 2.3), i n d i c a t e s t h a t Canadian sewage i s l i k e l y carbon l i m i t e d . Assuming t h a t carbon t o phosphorus r a t i o s are roughly e q u i v a l e n t , the economics f o r Bio-P removal w i l l be more f a v o u r a b l e f o r a h i g h s t r e n g t h sewage than f o r a low s t r e n g t h sewage. T h i s i s due t o the f a c t t h a t the c a p i t a l c o s t s a s s o c i a t e d w i t h a Bio-P r e t r o f i t are g e n e r a l l y p r o p o r t i o n a l t o the wastewater flow r a t e , whereas the s a v i n g s i n o p e r a t i n g c o s t s are g e n e r a l l y p r o p o r t i o n a l t o the mass of phosphorus removed. T h e r e f o r e , f o r two s i m i l a r p l a n t s having e q u i v a l e n t d e s i g n flow c a p a c i t i e s but d i f f e r e n t sewage s t r e n g t h s , the c a p i t a l c o s t s f o r Bio-P r e t r o f i t s w i l l be roughly e q u i v a l e n t but the s a v i n g s i n o p e r a t i n g c o s t s w i l l be g r e a t e r f o r the p l a n t having the h i g h e r i n f l u e n t BOD 5 and phosphorus c o n c e n t r a t i o n s . T h i s i s i l l u s t r a t e d through a comparison of the C a l g a r y and Edmonton p l a n t s . The C a l g a r y p l a n t has a h i g h e r flow r a t e and hence, the r e t r o f i t c a p i t a l c o s t s are s i g n i f i c a n t l y h i g h e r . - 285 -AVERAGE INFLUENT CONCENTRATIONS fma/L) PLANT BODc o TP TKN BOD„:TP B0D r:TKN 1. C a l g a r y 161 4.5 22.7* 36 7.1 2. Edmonton 214 7.3 34 29 6.3 3. Regina 238 7.7 31.3 31 7.6 4. Saskatoon 213 7.1 27.3 30 7.8 5. Windsor 110 5.2 23 21 4.8 6. Grimsby 123 5.1 22.4 24 5.5 7. M i l t o n 210 8.8 34 24 6.2 8. E l m i r a 189 7.5 48 25 3.9 9. W e l l e s l e y 150 5.5 28.4 27 5.3 TABLE 5.4 - SUMMARY OF INFLUENT SEWAGE CHARACTERISTICS * Based on an NH^ c o n c e n t r a t i o n o f 15.9 mg/L and an NH^:TKN r a t i o equal t o 0.7 - 286 -However, s i n c e Edmonton has a h i g h e r i n f l u e n t phosphorus c o n c e n t r a t i o n (7.3 ve r s u s 4.5 mg/L) o p e r a t i n g c o s t s a v i n g s from reduced chemical consumption are g r e a t e r than those which would be r e a l i z e d a t Ca l g a r y . T h e r e f o r e , the economics, a s s o c i a t e d w i t h Bio-P removal a t Edmonton, are s u p e r i o r t o those a t Calgary. The o p e r a t i n g c o s t s a v i n g s f o r the Edmonton p l a n t warrant some f u r t h e r d i s c u s s i o n s i n c e they are r e l a t e d t o the c h a r a c t e r i s t i c s o f the sewage. As shown i n Tab l e 5.1, o p e r a t i n g c o s t s a v i n g s f o r Edmonton appear d i s p r o p o r t i o n a t e l y h i g h r e l a t i v e t o the s a v i n g s which would be r e a l i z e d a t the Regina and Saskatoon p l a n t s g i v e n t h a t the i n f l u e n t sewage c h a r a c t e r i s t i c s are r o u g h l y e q u i v a l e n t . However, the Edmonton sewage appears t o have a h i g h s o l u b l e phosphorus f r a c t i o n a*s evidenced by TP removals o f approximately 10 p e r c e n t i n the primary c l a r i f i e r . Removals of 20 t o 25 per c e n t are r e a l i z e d i n the Regina and Saskatoon p l a n t s . T h e r e f o r e , h i g h e r alum c o n c e n t r a t i o n s would have t o be added a t Edmonton than would be r e q u i r e d a t Regina or Saskatoon. The VFA c o n c e n t r a t i o n of the i n f l u e n t sewage a l s o has a s i g n i f i c a n t impact on the v i a b i l i t y o f Bio-P removal. The presence o f c o n s i s t e n t c o n c e n t r a t i o n s o f approximately 15 mg/L of VFA's (as HAc) i n the i n f l u e n t c o u l d e l i m i n a t e the need f o r primary sludge f e r m e n t a t i o n . While t h e r e i s no evidence t o - 287 -suggest t h a t these c o n c e n t r a t i o n s may be pre s e n t , a recommended f i r s t s t e p i n e v a l u a t i n g the f e a s i b i l i t y o f Bio-P removal f o r a s p e c i f i c p r o j e c t , would be t o monitor VFA's i n the raw sewage. 5.4 P l a n t S i z e and C o n f i g u r a t i o n As shown i n Table 5.2 and 5.3, the use of Bio-P removal g e n e r a l l y becomes i n c r e a s i n g l y v i a b l e as p l a n t s i z e i n c r e a s e s . Assuming e q u i v a l e n t sewage compositions and p l a n t c o n f i g u r a t i o n s , o p e r a t i n g c o s t s a v i n g s should i n c r e a s e l i n e a r l y w i t h p l a n t s i z e s i n c e t h e u n i t p r i c e o f chemicals does not change s i g n i f i c a n t l y f o r the range of consumptions i n t h i s study (Haatinen, 1988). However, c a p i t a l c o s t expenditures w i l l not i n c r e a s e l i n e a r l y w i t h i n c r e a s e d p l a n t s i z e due t o the s c a l i n g e f f e c t a s s o c i a t e d w i t h the purchase and i n s t a l l a t i o n o f manufactured equipment. I t i s however, d i f f i c u l t t o assess whether t h e r e i s a p l a n t s i z e above which Bio-P removal i s economic. Canviro e t a l . (1986) suggest t h a t r e t r o f i t s become economic f o r c o n v e n t i o n a l a c t i v a t e d sludge p l a n t s having d e s i g n flows g r e a t e r than 13,600 3 m /d. However, Tab l e 5.2 shows t h a t should alum be used f o r 3 phosphorus removal, the r e t r o f i t o f the new 27,211 m /d Windsor 3 p l a n t and the 4,550 m /d E l m i r a p l a n t would be f a v o u r a b l e from an economic p e r s p e c t i v e . - 288 -However, the r e t r o f i t o f the e x i s t i n g 36,281 m /d Windsor p l a n t , 3 . 3 the 18,141 m /d Grimsby p l a n t and the 12,911 m /d M i l t o n p l a n t would not be e c o n o m i c a l l y a t t r a c t i v e . I t i s , t h e r e f o r e , concluded t h a t t h e c o n f i g u r a t i o n of the e x i s t i n g p l a n t i s an e q u a l l y important f a c t o r i n the p o t e n t i a l a t t r a c t i v e n e s s of a Bio-P r e t r o f i t . F a c t o r s which f a v o u r a b l y impact the economics f o r Bio-P removal are as f o l l o w s : i ) P l u g Flow Reactors The presence o f p l u g flow r e a c t o r s minimizes the amount of compartmentalization t o be added. In a d d i t i o n , the a e r a t i o n systems f o r p l u g flow r e a c t o r s are g e n e r a l l y more a p p l i c a b l e t o a Bio-P p r o c e s s than are the a e r a t i o n systems f o r completely mixed r e a c t o r s . For example, the c a p i t a l c o s t s r e q u i r e d t o r e t r o f i t the new Windsor p l a n t f o r Bio-P removal are l e s s than those r e q u i r e d f o r the s m a l l e r Grimsby and M i l t o n p l a n t s . T h i s i s e s s e n t i a l l y due t o the d i f f e r e n c e i n the c o s t o f r e t r o f i t t i n g p l u g flow r e a c t o r s v e r s u s the c o s t of r e t r o f i t t i n g completely mixed r e a c t o r s . S i m i l a r l y , the c o s t t o r e t r o f i t the completely mixed Ca l g a r y Bonnybrook r e a c t o r s (only one h a l f o f the t o t a l C a lgary r e a c t o r volume) i s approximately $1.2 m i l l i o n , whereas the c o s t t o r e t r o f i t the Edmonton Gold Bar p l u g flow r e a c t o r s would be o n l y $812,000. - 289 -i i ) Primary Sludge G r a v i t y T h i c k e n i n g The use o f e x i s t i n g g r a v i t y t h i c k e n e r s f o r primary sludge f e r m e n t a t i o n can r e s u l t i n c a p i t a l c o s t s a v i n g s . While c o n v e n t i o n a l l y designed t h i c k e n e r s may not o f f e r s u f f i c i e n t HRT f o r fermentation, the use o f e x i s t i n g t h i c k e n e r s w i l l d e f i n i t e l y reduce the s i z e of new f e r m e n t a t i o n f a c i l i t i e s . i i i ) Automated DO C o n t r o l The presence of automated DO c o n t r o l , e s p e c i a l l y i n a s m a l l p l a n t , s i g n i f i c a n t l y reduces the c a p i t a l c o s t a s s o c i a t e d w i t h a Bio-P r e t r o f i t . For example, twenty-seven pe r c e n t of the c a p i t a l c o s t a s s o c i a t e d w i t h the W e l l e s l e y r e t r o f i t ($14,000 out of $52,000) was a t t r i b u t a b l e t o the i n s t a l l a t i o n o f DO c o n t r o l f a c i l i t i e s . S i m i l a r l y , e i g h t e e n p e r c e n t of the c a p i t a l c o s t a s s o c i a t e d w i t h the E l m i r a r e t r o f i t ($70,000 out of $381,000) was a t t r i b u t a b l e t o DO c o n t r o l . i v ) Oxygen Supply System F l e x i b i l i t y The a b i l i t y t o c o n t r o l the oxygen supply t o a number of d i f f e r e n t "zones" i n the b i o r e a c t o r i s d e s i r a b l e . An i d e a l oxygen supply system would c o n s i s t of an a i r supply header w i t h numerous t a k e - o f f s s u p p l y i n g i s o l a t e d groups o f d i f f u s e r s . V a l v e s would c o n t r o l the supply of a i r from each t a k e - o f f . - 290 -5.5 Sludge P r o c e s s i n g The common p r a c t i c e o f anaerobic d i g e s t i o n o f combined primary and waste a c t i v a t e d sludges, f o l l o w e d by dewatering and l a n d a p p l i c a t i o n i s not f a v o u r a b l e from a Bio-P p e r s p e c t i v e i f the d i g e s t o r supernatant and/or dewatering s u p e r n a t a n t / f i l t r a t e streams are r e t u r n e d t o the p l a n t . As p r e v i o u s l y mentioned, the r e l e a s e o f phosphorus under anaerobic d i g e s t i o n combined w i t h p r o v i n c i a l requirements f o r sludge s t a b i l i z a t i o n p r i o r t o land a p p l i c a t i o n , n e c e s s i t a t e s continued use of ana e r o b i c d i g e s t i o n combined w i t h l i m e treatment o f the r e c y c l e streams p r i o r t o be i n g r e t u r n e d t o the p l a n t . The c a p i t a l and o p e r a t i n g c o s t s a s s o c i a t e d w i t h t h i s o p e r a t i o n are v e r y h i g h as shown i n Tabl e 5.5. Furthermore, the a d d i t i o n o f lime may a c t u a l l y r e s u l t i n i n c r e a s e d sludge p r o d u c t i o n r e l a t i v e t o a comparable chemical phosphorus removal p r o c e s s . T h i s was found t o be the case f o r the Calgary, Edmonton, Regina and Saskatoon p l a n t s . The use o f r e c y c l e streams f o r i r r i g a t i o n purposes would e l i m i n a t e the need f o r lime treatment f a c i l i t i e s and would t h e r e f o r e make Bio-P more a t t r a c t i v e from an economic p e r s p e c t i v e . T h i s i s c u r r e n t l y p r a c t i c e d a t the C a l g a r y p l a n t d u r i n g the summer months. An a l t e r n a t e method o f s t o r a g e and/or d i s p o s a l would be r e q u i r e d d u r i n g the w i n t e r months i f t h i s were t o be implemented f o r a Bio-P p l a n t . - 291 -Bio-P removal i s more amenable t o o t h e r methods of sludge p r o c e s s i n g . As shown f o r the Windsor and E l m i r a p l a n t s , Bio-P removal r e s u l t s i n reduced sludge p r o d u c t i o n when anaerobic and/or a e r o b i c d i g e s t i o n are not used. T h e r e f o r e , as l o n g as phosphorus r e l e a s e does not occur . i n the sludge p r o c e s s i n g o p e r a t i o n s or r e l e a s e d phosphorus i s not r e t u r n e d t o the mainstream p r o c e s s , the use of Bio-P removal w i l l be advantageous from a sludge p r o c e s s i n g p e r s p e c t i v e . Should l a n d a p p l i c a t i o n of sludge be d e s i r e d f o r a new f a c i l i t y , the use of composting should be c o n s i d e r e d . T h i s w i l l r e s u l t i n a s t a b i l i z e d sludge s u i t a b l e f o r l a n d a p p l i c a t i o n and w i l l not r e s u l t i n phosphorus r i c h r e c y c l e streams b e i n g r e t u r n e d t o the p l a n t . Composting w i l l , however, not a l l o w f o r the r e c o v e r y o f methane gas f o r h e a t i n g and/or power g e n e r a t i o n purposes. 5.6 N u t r i e n t Removal Standards From a Bio-P p e r s p e c t i v e , the requirement f o r NH 3 or t o t a l n i t r o g e n removal i s a c o m p l i c a t i n g requirement t h a t c o u l d a d v e r s e l y a f f e c t the phosphorus removal performance of the p r o c e s s . F o r both b i o l o g i c a l phosphorus/ammonia and b i o l o g i c a l p hosphorus/nitrogen removal, p a r t i c u l a r c a r e must be taken t o ensure t h a t n i t r a t e s are not r e t u r n e d t o the a n a e r o b i c zone. For t o t a l n i t r o g e n removal, t h i s may be i m p o s s i b l e i f adequate carbon - 292 -( $ X 10 3) PLANT CAPITAL COST ANNUAL COST OF LIME 1. C a l g a r y 706 173 2. Edmonton 1,118 361 3. Regina 649 136 4. Saskatoon 841 150 5. Grimsby 265 12 6. M i l t o n 199 5 TABLE 5.5 - CAPITAL AND CHEMICAL COSTS ASSOCIATED WITH LIME TREATMENT OF DIGESTOR SUPERNATANT - 293 -t o n i t r o g e n r a t i o s are not c o n t a i n e d i n the wastewater. A comparison o f the BOD^:TKN r a t i o s f o r the p l a n t s s t u d i e d (see T a b l e 5.4) w i t h the minimum r a t i o s recommended by Evans and Crawford (1985) (see Tab l e 2.3) i n d i c a t e s t h a t the carbon t o n i t r o g e n r a t i o s i n Canadian sewage are marginal w i t h r e s p e c t t o t o t a l n i t r o g e n removal. N i t r o g e n removal p l a n t s g e n e r a l l y operate a t a r e l a t i v e l y l o n g SRT (10 t o 40 days) . T h i s c r e a t e s another problem from a Bio-P removal p e r s p e c t i v e , i n t h a t l o n g SRT p l a n t s minimize sludge p r o d u c t i o n and hence, reduce the phosphorus removal p o t e n t i a l o f the pr o c e s s . T h e r e f o r e , i f n i t r o g e n removal i s not r e q u i r e d , i t should be avoided. I d e a l l y , the optimal method of o p e r a t i n g a Bio-P removal p l a n t would be t o minimize both the SRT and the b i o r e a c t o r DO c o n c e n t r a t i o n i n order t o i n h i b i t n i t r i f i c a t i o n . 5.7 New Versus R e t r o f i t F a c i l i t i e s The economics of Bio-P removal should be b e t t e r f o r new f a c i l i t i e s than f o r p l a n t r e t r o f i t s . The p l a n t l a y o u t can be o p t i m i z e d w i t h r e s p e c t t o the l o c a t i o n o f the primary sludge fermenter; t h e b i o r e a c t o r s l a y o u t s can be o p t i m i z e d t o bes t accommodate the anaerobic, anoxic and a e r o b i c zones; and sludge h a n d l i n g u n i t o p e r a t i o n s can be s e l e c t e d t o b e s t handle Bio-P sl u d g e s . - 294 -Three e s s e n t i a l l y new f a c i l i t i e s (Regina, Saskatoon and Windsor) were c o n s i d e r e d i n t h i s study. While the l o c a t i o n of the fermenter(s) was somewhat l i m i t e d by e x i s t i n g f a c i l i t i e s , and sludge h a n d l i n g techniques were a l r e a d y s e l e c t e d and i n p l a c e , some leeway was a v a i l a b l e w i t h r e s p e c t t o b i o r e a c t o r l a y o u t and fermenter d e s i g n . As a r e s u l t , the economics a s s o c i a t e d with Bio-P removal f o r Regina and Saskatoon are q u i t e f a v o u r a b l e . The economics f o r the Windsor p l a n t , w h i l e not c o m p e t i t i v e w i t h a chemical removal process, were the most f a v o u r a b l e f o r any of the O n t a r i o p l a n t s . In a d d i t i o n , the economics of Bio-P removal would be v e r y a t t r a c t i v e i n the event t h a t the use of alum was r e q u i r e d i n p l a c e of the spent aluminum c a t a l y s t . 5.8 O v e r a l l Assessment Based on the above d i s c u s s i o n i t can be concluded t h a t Bio-P removal i s most a t t r a c t i v e when the f o l l o w i n g c o n d i t i o n s are met: i ) Inexpensive i n d u s t r i a l by-products are not a v a i l a b l e f o r chemical phosphorus removal. i i ) The sewage i s s t r o n g and c o n t a i n s g r e a t e r than 15 mg/L of VFA's as HAc ( f o r the removal of 4 t o 5 mg/L of phosphorus). i i i ) The proposed p l a n t i s l a r g e and i s a new f a c i l i t y . - 295 -i v ) In the case of a p l a n t r e t r o f i t , the e x i s t i n g p l a n t c o n t a i n s p l u g flow r e a c t o r s , g r a v i t y t h i c k e n e r s , automated DO c o n t r o l and a f l e x i b l e oxygen supply system. v) The sludge p r o c e s s i n g f a c i l i t i e s do not i n v o l v e r e c y c l i n g s u p e r n a t a n t / f i l t r a t e streams back t o the p l a n t . v i ) Combined n i t r o g e n and phosphorus removal i s not r e q u i r e d . Without r e v i e w i n g each i n d i v i d u a l p l a n t , i t i s d i f f i c u l t t o s p e c u l a t e on the exact number of p l a n t s i n Canada which are amenable t o Bio-P removal. However, i t can be concluded t h a t the technology appears t o be the most a p p l i c a b l e t o p l a n t s l o c a t e d i n A l b e r t a and Saskatchewan. Reasons f o r t h i s are as f o l l o w s : i ) I n d u s t r i a l by-products are not r e a d i l y a v a i l a b l e i n A l b e r t a and Saskatchewan f o r chemical phosphorus removal. Alum would l i k e l y have t o be used a t c o n s i d e r a b l e expense. i i ) The t e r r a i n i s r e l a t i v e l y f l a t and hence, long r e t e n t i o n times can be expected i n the sewers. T h e r e f o r e , the sewage may be i n a fermented s t a t e when i t reaches the treatment p l a n t . - 296 -i i i ) The c l i m a t e i s r e l a t i v e l y dry. T h e r e f o r e , i n f i l t r a t i o n i n t o s a n i t a r y sewers should be minimal and sewage s t r e n g t h s should be r e l a t i v e l y h i g h . Sewage c h a r a c t e r i s t i c s from Edmonton, Regina and Saskatoon seem t o support t h i s h y p o t h e s i s . i v ) Phosphorus removal i n A l b e r t a w i l l l i k e l y be more s t r i c t l y e n f o r c e d i n the f u t u r e y ears (Spink, 1988). S i m i l a r l y , the requirement f o r treatment p l a n t upgrading i n Regina and Saskatoon ( i n c l u d i n g phosphorus removal) i n d i c a t e s t h a t phosphorus removal may become more common i n Saskatchewan. v) The m a j o r i t y o f the towns i n A l b e r t a and Saskatchewan are c u r r e n t l y s e r v i c e d by lagoons. As these towns grow, upgrading t o a c t i v a t e d sludge p r o c e s s e s may be r e q u i r e d . S i n c e the economic b e n e f i t s of Bio-P removal are maximized i n new f a c i l i t i e s , the a t t r a c t i v e n e s s o f Bio-P removal w i l l be maximized i f g e n e r a l treatment p l a n t upgrading i s r e q u i r e d i n c o n j u n c t i o n w i t h phosphorus removal. Bio-P removal would not be r e s t r i c t e d t o l a r g e p l a n t s i n A l b e r t a and Saskatchewan. A n a l y s i s f o r the new Windsor p l a n t and the E l m i r a p l a n t i n d i c a t e t h a t Bio-P removal can be e c o n o m i c a l l y v i a b l e f o r s m a l l e r p l a n t s g i v e n the r i g h t p r o c e s s c o n f i g u r a t i o n . - 297 -The use of Bio-P removal i n O n t a r i o would l i k e l y be 3 r e s t r i c t e d t o v e r y l a r g e p l a n t s ( g r e a t e r than 300,000 m /d) which are w e l l c o n f i g u r e d f o r a Bio-P p r o c e s s . T h i s i s due t o the low p r i c e c u r r e n t l y a s s o c i a t e d w i t h phosphorus removal c h e m i c a l s . As shown i n T a b l e 5.3, f e r r o u s or f e r r i c c h l o r i d e c o s t s would have t o exceed $724 per tonne of i r o n f o r Bio-P removal t o be e c o n o m i c a l l y a t t r a c t i v e f o r a p l a n t having the same s i z e and c o n f i g u r a t i o n as the Edmonton Gold Bar p l a n t . T h e r e f o r e , u n l e s s the use o f i n d u s t r i a l by-products f o r phosphorus removal i s r e s t r i c t e d , or the c o s t of these products d r a m a t i c a l l y i n c r e a s e s , the use of Bio-P removal i n O n t a r i o i s e c o n o m i c a l l y j u s t i f i a b l e i n o n l y a l i m i t e d number of cases. Some p o t e n t i a l may e x i s t f o r the use of the technology i n Quebec. Inf o r m a t i o n obtained from the Quebec M i n i s t r y of the Environment (Karazivan, 1987) i n d i c a t e s t h a t t h e r e are approximately f i f t y p l a n t s i n the p r o v i n c e which c u r r e n t l y remove phosphorus. Of these p l a n t s approximately t w e n t y - f i v e use e i t h e r the a c t i v a t e d sludge or extended a e r a t i o n process and hence, c o u l d be r e t r o f i t t e d f o r Bio-P removal. Beland (1987) i n d i c a t e s t h a t a number o f the r e c e n t l y designed p l a n t s i n the p r o v i n c e have been designed t o accommodate an a n a e r o b i c zone a t the f r o n t o f the a e r a t i o n b a s i n . However, the c o s t of phosphorus removal che m i c a l s i n Quebec i s r e l a t i v e l y i n e x p e n s i v e due t o the p r o x i m i t y t o s t e e l m i l l s f o r p i c k l e l i q u o r supply. U f f e n (1988) - 298 -r e p o r t s t h a t c u r r e n t f e r r o u s c h l o r i d e and f e r r i c c h l o r i d e p r i c e s i n Quebec are approximately $1050 per tonne and $1155 per tonne r e s p e c t i v e l y (FOB M o n t r e a l ) . These are s l i g h t l y h i g h e r than those i n O n t a r i o . However, as shown i n Table 5.2, o n l y the C a l g a r y and Edmonton p l a n t s would be ca n d i d a t e s f o r Bio-P removal at these chemical p r i c e s . T h e r e f o r e , the p o t e n t i a l f o r the use of the pr o c e s s i n the p r o v i n c e i s , again, l i k e l y l i m i t e d t o l a r g e and s u i t a b l y c o n f i g u r e d p l a n t s . As p r e v i o u s l y mentioned, the use of Bio-P removal i n B r i t i s h Columbia has been proven through the Kelowna f a c i l i t y , and as a r e s u l t , new p l a n t s are c u r r e n t l y b e i n g c o n s t r u c t e d i n P e n t i c t o n and Westbank. However, s i n c e a d d i t i o n a l phosphorus removal requirements w i l l not l i k e l y be promulgated i n the near f u t u r e , the use f o r the technology i n B r i t i s h Columbia i s pr o b a b l y l i m i t e d . Since phosphorus removal standards f o r Manitoba, the Maritimes and the Yukon and Northwest T e r r i t o r i e s are u n l i k e l y to come i n t o e x i s t e n c e i n the f o r e s e e a b l e f u t u r e , n o n - e x i s t e n t , the p o t e n t i a l f o r Bio-P removal i n these p a r t s of the cou n t r y i s minimal. - 299 -5.9 Future Research Needs Through t h i s study i t was determined t h a t t h e r e are a number of a s p e c t s of Bio-P technology which, i f f u r t h e r researched, c o u l d a s s i s t i n both the d e s i g n and o p t i m i z a t i o n of Bio-P removal p r o c e s s e s . Areas of r e s e a r c h r e q u i r i n g f u r t h e r study are as f o l l o w s . i ) K i n e t i c s of Bio-P Removal In o r d e r t o a c c u r a t e l y p r e d i c t the performance of a Bio-P process w i t h r e s p e c t t o phosphorus removal, a manageable k i n e t i c model i s r e q u i r e d . I t i s f e l t t h a t such a model should be a b l e t o p r e d i c t phosphorus uptake as a f u n c t i o n of i n f l u e n t carbon, anaerobic zone VFA c o n c e n t r a t i o n , n i t r a t e c o n c e n t r a t i o n r e t u r n e d t o the anaerobic zone, i n f l u e n t phosphorus, a e r a t i o n time and mass o f a c t i v e biomass. In a d d i t i o n t o phosphorus removal p r e d i c t i o n s , the k i n e t i c s a s s o c i a t e d w i t h sludge p r o d u c t i o n f o r Bio-P p r o c e s s e s r e q u i r e f u r t h e r study. Qasim and Udomsinrot (1987) have c a l c u l a t e d t r a d i t i o n a l k i n e t i c c o e f f i c i e n t s (Y, k., k , k) f o r an a n o x i c / a n a e r o b i c / a e r o b i c p r o c e s s . Q S More work needs t o be done t o c o n f i r m t h e s e r e s u l t s , and t o assess the impacts of v a r i o u s parameters (e.g. a n a e r o b i c zone VFA c o n c e n t r a t i o n s , a n a e r o b i c zone n i t r a t e c o n c e n t r a t i o n s , etc.) on the c o e f f i c i e n t s . - 300 -i i ) S h ort SRT Bio-P Removal Because the requirements f o r year-round ammonia removal and t o t a l n i t r o g e n removal are not widespread throughout Canada, the m a j o r i t y o f a c t i v a t e d sludge p l a n t s operate a t a r e l a t i v e l y s h o r t SRT (5 t o 10 da y s ) . In a d d i t i o n , because the occurrence o f n i t r i f i c a t i o n i n a Bio-P p l a n t r e s u l t s i n i n c r e a s e d c a p i t a l c o s t s , o p e r a t i n g c o s t s and o p e r a t i n g complexity, t h e r e appears t o be some i n c e n t i v e t o minimize n i t r i f i c a t i o n i f i t i s not r e q u i r e d . T h e r e f o r e , i t wold be u s e f u l t o i n v e s t i g a t e the minimum SRT r e q u i r e d f o r Bio-P removal. In c o n j u n c t i o n w i t h t h i s work i t would be u s e f u l t o assess the impact of v a r y i n g the a e r a t e d zone DO c o n c e n t r a t i o n s s i n c e n i t r i f i c a t i o n can be i n h i b i t e d by low q u a n t i t i e s o f DO. i i i ) A n o x i c / A n a e r o b i c / A e r o b i c Processs T h i s study has shown t h a t t h e r e are economic b e n e f i t s t o t he a n o x i c / a n a e r o b i c / a e r o b i c p r o c e s s . A d d i t i o n a l r e s e a r c h i s r e q u i r e d t o c o n f i r m the v i a b i l i t y o f the p r o c e s s . - 301 -i v ) Primary Sludge Fermentation K i n e t i c s In d e s i g n i n g the fermenters f o r t h i s study, i t was assumed t h a t s u f f i c i e n t q u a n t i t i e s o f VFA's c o u l d be generated i f c e r t a i n s i z i n g c r i t e r i a were a p p l i e d t o the fermenter and i t s a n c i l l a r y f a c i l i t i e s . The development of a k i n e t i c model t o p r e d i c t VFA p r o d u c t i o n c o u l d r e s u l t i n a more e f f i c i e n t l y designed system and hence, c o u l d improve the economics f o r Bio-P removal. I t i s f e l t t h a t the model should be a b l e t o compute VSS d e s t r u c t i o n and VFA p r o d u c t i o n as a f u n c t i o n of VSS l o a d i n g , s o l i d s r e t e n t i o n time, h y d r a u l i c r e t e n t i o n time and temperature. v) Primary Sludge Fermentation Through G r a v i t y  T h i c k e n i n g As shown i n t h i s study, the use o f a g r a v i t y t h i c k e n e r f o r primary sludge f e r m e n t a t i o n i s r e q u i r e d should an a n o x i c / a n a e r o b i c / a e r o b i c process be employed. The d e s i g n o f a t h i c k e n e r f o r primary sludge f e r m e n t a t i o n , however, r e q u i r e s o p t i m i z a t i o n . Items r e q u i r i n g r e s o l u t i o n i n c l u d e : Does the s u r f a c e o f the t h i c k e n e r need t o be covered t o ensure anaerobic c o n d i t i o n s ? - 302 -What i s the optimal r e t e n t i o n time f o r s o l i d s i n the t h i c k e n e r ? Is a sludge c o l l e c t o r rake r e q u i r e d ? What i s the optimal underflow s o l i d s r e c y c l e r a t e ? v i ) Phosphorus Release During Anaerobic D i g e s t i o n Because o f the wide use o f anaerobic d i g e s t i o n i n the country, i t i s l i k e l y t h a t r e t r o f i t Bio-P processes w i l l be r e q u i r e d t o adapt t o t h i s method of sludge s t a b i l i z a t i o n . T h e r e f o r e , lime treatment of the d i g e s t o r supernatant w i l l l i k e l y be r e q u i r e d . For the purposes of t h i s study, lime q u a n t i t i e s and lime a d d i t i o n f a c i l i t y d e s i g ns were based on assumptions r e g a r d i n g the amount of phosphorus r e l e a s e which w i l l o ccur d u r i n g the d i g e s t i o n p r o c e s s . These assumptions were based on P h o s t r i p data and the work of Deakyne e t a l . (1984) and Murakami e t a l . (1987). However, more r e s e a r c h i s warranted i n o r d e r t o p r e d i c t the amount of phosphorus r e l e a s e w i t h r e s p e c t t o d i g e s t i o n time. In a d d i t i o n , s t u d i e s on the f e a s i b i l i t y o f lime treatment of d i g e s t o r supernatant would be b e n e f i c i a l . I t i s f e l t t h a t the l a c k o f knowledge a s s o c i a t e d w i t h the above s i x a s p e c t s o f Bio-P removal, r e s u l t e d i n c o n s e r v a t i v e assumptions b e i n g made f o r the p r e p a r a t i o n o f the r e t r o f i t d e s i g n s i n t h i s study. T h e r e f o r e , f u r t h e r r e s e a r c h i n t o these areas c o u l d improve the economics a s s o c i a t e d w i t h Bio-P removal. - 303 -6.0 CONCLUSIONS AND RECOMMENDATIONS 6.1 C o n c l u s i o n s 1. Of the nine p l a n t s evaluated, Bio-P removal was found to be e c o n o m i c a l l y a t t r a c t i v e f o r the C a l g a r y Bonnybrook, Edmonton Gold Bar, Saskatoon Mclvor Weir and Regina wastewater treatment p l a n t s . Bio-P removal was not found to be e c o n o m i c a l l y f e a s i b l e f o r the Windsor L i t t l e R i v e r , Grimsby Baker Road, M i l t o n , E l m i r a and W e l l e s l e y p l a n t s . t h a t alum would be used f o r a comparable phosphorus removal process, Bio-P removal was be e c o n o m i c a l l y j u s t i f i a b l e f o r p l a n t s i z e s as 4,550 m3/d. 3. Bio-P removal appears to be most a p p l i c a b l e to p l a n t s l o c a t e d i n A l b e r t a and Saskatchewan as a r e s u l t o f the r e l a t i v e l y h i g h c o s t o f phosphorus removal chemicals i n these p r o v i n c e s . 2. Assuming chemical found to small as 4. The use of Bio-P removal i n O n t a r i o and Quebec i s 3 l i k e l y l i m i t e d t o l a r g e (>300,000 m /d) and s u i t a b l y c o n f i g u r e d p l a n t s , u n l e s s r e s t r i c t i o n s are p l a c e d on - 304 -the use of i n d u s t r i a l by-products f o r chemical phosphorus removal, or the p r i c e o f the s e by-products i n c r e a s e s s i g n i f i c a n t l y . 5. The f u t u r e use of Bio-P removal i n B r i t i s h Columbia i s l i k e l y l i m i t e d as a r e s u l t o f the u n l i k e l i h o o d o f a d d i t i o n a l phosphorus removal requirements throughout the p r o v i n c e . 6. The p o t e n t i a l f o r Bio-P removal i n the r e s t o f Canada i s r e l a t i v e l y l i m i t e d due t o the u n l i k e l i h o o d o f f u t u r e phosphorus removal requirements. 7. Bio-P removal g e n e r a l l y becomes more v i a b l e as the s i z e of the p l a n t i n c r e a s e s . However, the c o n f i g u r a t i o n of the p l a n t i s c r i t i c a l t o the economic v i a b i l i t y o f Bio-P removal. 8. Bio-P removal appears t o be more a t t r a c t i v e f o r new i n s t a l l a t i o n s than f o r p l a n t r e t r o f i t s . 9 . C h a r a c t e r i s t i c s o f the i n f l u e n t sewage are very important t o the t e c h n i c a l and economic f e a s i b i l i t y of Bio-P removal. - 305 -10. The use o f the a n o x i c / a n a e r o b i c / a e r o b i c process i n c o n j u n c t i o n w i t h primary sludge f e r m e n t a t i o n v i a g r a v i t y t h i c k e n i n g appears t o be v e r y a p p l i c a b l e t o Canadian p l a n t s and o f f e r s p o t e n t i a l c a p i t a l and o p e r a t i n g c o s t s a v i n g s r e l a t i v e t o o t h e r Bio-P p r o c e s s e s . 11. The common p r a c t i c e o f anaerobic sludge d i g e s t i o n combined wi t h sludge dewatering and l a n d a p p l i c a t i o n i s not f a v o u r a b l e from a Bio-P p e r s p e c t i v e u n l e s s a method f o r the re-use or d i s p o s a l of the s u p e r n a t a n t / f i l t r a t e streams can be developed. 6.2 Recommendations 1. F u l l - s c a l e t e s t i n g o f Bio-P removal a t the Calgary Bonnybrook p l a n t i s warranted. 2. Manageable k i n e t i c models f o r p r e d i c t i o n s o f VFA p r o d u c t i o n from primary sludge f e r m e n t a t i o n , and phosphorus uptake i n the b i o r e a c t o r , should be developed. 3. F u r t h e r r e s e a r c h on s h o r t SRT Bio-P removal i s warranted. P i l o t and f u l l - s c a l e t e s t i n g of the a n o x i c / a n a e r o b i c / a e r o b i c p r o c e s s should be c o n s i d e r e d . Research on the use of g r a v i t y t h i c k e n i n g as a method of primary sludge f e r m e n t a t i o n should be c a r r i e d out. F u r t h e r r e s e a r c h on phosphorus r e l e a s e d u r i n g anaerobic d i g e s t i o n , and the subsequent p r e c i p i t a t i o n of the r e l e a s e d phosphorus wi t h lime i s warranted. - 307 -REFERENCES AIR PRODUCTS AND CHEMICALS INC. (1980), " P r o d u c t i o n o f Non-B u l k i n g A c t i v a t e d Sludge", Canadian Patent No. 1078977. ALBERTA ENVIRONMENT (1982), G u i d e l i n e s f o r the A p p l i c a t i o n of M u n i c i p a l Wastewater Sludges t o A g r i c u l t u r a l Lands i n A l b e r t a , A l b e r t a Environment Standards and Approvals D i v i s i o n , E a r t h S c i e n c e s D i v i s i o n . ANDERSON, B. (1988), U n i v e r s i t y o f B r i t i s h Columbia Department of C i v i l E n g i n e e r i n g , p e r s o n a l communication. ARCHER, J.D. 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WHITMAN, REQUARDT and A s s o c i a t e s (1982), C i t y o f Ba l t i m o r e Maryland, Patapsco Wastewater Treatment P l a n t , A n a l y s i s o f Phosphorus Removal A l t e r n a t i v e s f o r 70 MGD P l a n t . YEE, A. (1987), C i t y o f Edmonton Water and S a n i t a t i o n Dept., Edmonton, A l b e r t a , p e r s o n a l communication. 3 i S «-APPENDIX A LIST OF SYMBOLS AND ABBREVIATIONS - 3.16 -APPENDIX A LIST OF SYMBOLS AND ABBREVIATIONS AE Process A n a l y z e r AIC Process A n a l y s i s I n d i c a t o r / C o n t r o l l e r AIR Process A n a l y s i s I n d i c a t o r / R e c o r d e r AT Process A n a n l y s i s T r a n s m i t t e r Bio-P B i o l o g i c a l Phosphorus BOD Bioch e m i c a l Oxygen Demand BOD 5 5 day BOD COD Chemical Oxygen Demand DAF D i s s o l v e d A i r F l o t a t i o n DO D i s s o l v e d Oxygen FC Flow C o n t r o l l e r FE Flow Measurement Element FR Flow Recorder FT Flow Measurement T r a n s m i t t e r HAc A c e t i c A c i d HRT H y d r a u l i c R e t e n t i o n Time IRR I n t e r n a l Rate of Return MTO M a t e r i a l Take-Off NH^ Ammonia N0 3 N i t r a t e OME Ont a r i o M i n i s t r y o f the Environment ORP O x i d a t i o n Reduction P o t e n t i a l PD P o s i t i v e Displacement PHB Poly-B-hydroxybutyrate pmf Proton motive f o r c e RAS Return A c t i v a t e d Sludge RBC R o t a t i n g B i o l o g i c a l C o n t a c t o r SBR Sequencing Batch Reactor SP S o l u b l e Phosphorus SRT Sludge Age SS Suspended S o l i d s SWD Side Wall Depth - 317 -TIC T o t a l I n s t a l l e d Cost TKN T o t a l Kjedahl N i t r o g e n TP T o t a l Phosphorus TSS • T o t a l Suspended S o l i d s USEPA U n i t e d S t a t e s Environmental P r o t e c t i o n Agency VFA V o l a t i l e F a t t y A c i d VSS V o l a t i l e Suspended S o l i d s WAS Waste A c t i v a t e d Sludge 3>"? «-APPENDIX B BIOLOGICAL NITROGEN REMOVAL OVERVIEW - 318 -A P P E N D I X B B I O L O G I C A L N I T R O G E N R E M O V A L O V E R V I E W In o r d e r t o promote the growth of Bio-P b a c t e r i a i n a secondary treatment p l a n t , the b i o l o g i c a l s o l i d s must be exposed t o ana e r o b i c c o n d i t i o n s a t some time d u r i n g the treatment p r o c e s s . Because anaerobic c o n d i t i o n s r e f e r t o the absence of both d i s s o l v e d oxygen (DO) and n i t r a t e (N0 3), the degree o f n i t r o g e n removal which occurs i n the p l a n t i s of c o n s i d e r a b l e importance t o the s e l e c t i o n o f a pro c e s s c o n f i g u r a t i o n . In c o n v e n t i o n a l domestic wastewater, n i t r o g e n i s found p r i m a r i l y i n the form of ammonia (NH 3) and t o a l e s s e r extent, o r g a n i c n i t r o g e n . T o t a l K j e l d a h l n i t r o g e n (TKN) measurements r e f e r t o the t o t a l o f the o r g a n i c and ammonia n i t r o g e n . Under a e r o b i c c o n d i t i o n s , ammonia can be used by two groups o f b a c t e r i a (Nitrosomonas and N i t r o b a c t e r ) t o produce energy f o r c e l l u l a r growth. In produc i n g energy, a two-stage b i o l o g i c a l r e a c t i o n occurs i n which Nitrosomonas f i r s t o x i d i z e s ammonia t o n i t r i t e ( N 0 2 ) a n < * then N i t r o b a c t e r o x i d i z e s n i t r i t e t o n i t r a t e . T h i s i s i l l u s t r a t e d by the f o l l o w i n g r e a c t i o n s : - 319 -Nitrosomonas 2NH 3 + 30 2 + 2H+ + 2 H 20 N i t r o b a c t e r 2N0 2 + 0 2 In wastewater treatment p l a n t s r e q u i r e d t o remove ammonia, c o n d i t i o n s i n the b i o r e a c t o r are c r e a t e d t o promote the growth of Nitrosomonas and N i t r o b a c t e r . These b a c t e r i a have low, temperature dependent growth r a t e s ( M e t c a l f and Eddy, 1979) and hence, long SRT's are r e q u i r e d t o ensure n i t r i f i c a t i o n , e s p e c i a l l y a t low wastewater temperatures. Because o f the temperature dependency of the n i t r i f y i n g b a c t e r i a growth r a t e s , n i t r i f i c a t i o n o f t e n occurs i n c o n v e n t i o n a l a c t i v a t e d sludge p l a n t s d u r i n g p e r i o d s of warm weather. S i n c e n i t r i f i c a t i o n consumes oxygen, the occurrence o f n i t r i f i c a t i o n can have adverse e f f e c t s on treatment p l a n t o p e r a t i o n i f i t occurs but i s not designed f o r . Under c o n d i t i o n s d e v o i d of oxygen, n i t r a t e can be used i n p l a c e of oxygen as the t e r m i n a l e l e c t r o n a c c e p t o r i n r e s p i r a t i o n r e a c t i o n s by f a c u l t a t i v e , h e t e r o t r o p h i c b a c t e r i a . T h i s i s known as d e n i t r i f i c a t i o n and i s i l l u s t r a t e d by the f o l l o w i n g r e a c t i o n : - 320 -d e n i t r i f y i n g Carbon + NO > N 2(g) + CO 2(g) S u b s t r a t e b a c t e r i a C o n d i t i o n s d e v o i d of oxygen but c o n t a i n i n g n i t r o g e n are known as "anoxic" c o n d i t i o n s . The requirement f o r d e n i t r i f i c a t i o n i n wastewater treatment p l a n t s i s not as widespread as the requirement f o r n i t r i f i c a t i o n . As o f 1984, o n l y two p l a n t s i n Canada (Kelowna, B.C. and O r a n g e v i l l e , Ontario) were r e q u i r e d t o p r o v i d e d e n i t r i f i c a t i o n ( O ' R e i l l y , 1984). However, i f i t i s proposed t o employ Bio-P removal i n a c t i v a t e d sludge p l a n t s which n i t r i f y , p r o v i s i o n must be made f o r some degree of n i t r i f i c a t i o n , s i n c e n i t r a t e s w i l l be r e t u r n e d t o the b i o r e a c t o r i n the r e t u r n a c t i v a t e d sludge. 3 0-<5 CL APPENDIX C CAPITAL COST ESTIMATING SUPPORT DATA APPENDIX C CAPITAL COST ESTIMATING SUPPORT DATA A. MECHANICAL EQUIPMENT 1. G r a v i t y T h i c k e n e r Mechanical Components In c l u d e s rake arm, s c r a p e r b l a d e s , walkway, e f f l u e n t w eir and i n f l u e n t w e l l . DIAMETER SWD MAT'L COST SOURCE BULK FACTOR SOURCE (m) (m) ($) 21 3.5 98,000 1 1.84 2 20 3.5 95,072 1 1.84 2 15 3.5 80,000 1 1. 84 2 12 3.5 69,625 1 1.84 2 10.5 3.5 65,000 1 1. 84 2 10 3.5 62,724 1 1.84 2 8.8 3.5 58,000 1 1.84 2 6.6 3.5 48,962 1 1.84 2 - 322 -2. C l a r i f i e r s I n c l u d e s s t e e l tank, rake arm, scaper b l a d e s , walkway, e f f l u e n t w e i r and i n f l u e n t w e l l . DIAMETER (m) 6.1 4.1 2.1 MAT'L COST ($) 66,000 47,274 27,800 SOURCE 3 3 3 BULK FACTOR 2.2 2.1 1.9 SOURCE 2 2 2 3. Fermenter Supernatant Pumps 1 I n c l u d e s pump and d r i v e r . DRIVER BULK Q TDH POWER MAT'L COST SOURCE FACTOR SOURCE (L/S) (m) (kW) ($) 100 35 50 13,000 3 3.8 2 45 20 13 4.700 3 3.8 2 38 19 10 4,192 3 3.8 2 26 21 7.8 3,753 3 3.8 2 11 20 2.9 2,220 3 3.8 2 7.9 20 2.2 2,220 3 3.8 2 5.2 20 1.5 2,000 3 3.8 2 3.7 20 0.8 1,882 3 3.8 2 1.3 20 0.4 1,882 - 323 -4. Primary C l a r i f i e r Underflow Pumps Inc l u d e s pump and d r i v e r . 2 TDH DRIVER POWER MAT'L COST SOURCE BULK FACTOR SOURCE (L/S) (m) (kW) ($) 7.5 16 1.8 2,145 4 3.8 2 2.3 21 0.7 2,076 4 3.8 2 5. Fermenter Underflow Recvcle Pumps Incl u d e s pump and d r i v e r . Q TDH DRIVER POWER MAT'L COST SOURCE BULK FACTOR SOURCE (L/S) (m) (kW) ($) 100 15 21 6,535 4 3.8 2 45 15 9.5 4,192 4 3.8 2 10.5 49 9.4 4,192 4 3.8 2 38 15 7.9 3,753 4 3.8 2 26 15 5.5 3,020 4 3.8 2 6.3 49 5.4 3,020 4 3.8 2 5.2 15 1.4 2,000 3 3.8 2 3.7 15 0.8 1,900 3 3.8 2 2.3 17 0.6 1,882 3 3.8 2 - 324 -6. Fermenter Wastage Pumps In c l u d e s pump and d r i v e r . Q TDH DRIVER POWER MAT'L COST SOURCE BULK FACTOR SOURCE (L/S) (m) (KW) ($) 100 23 32 8,700 3 3.8 2 45 26 16 5,500 3 3.8 2 26 27 9.8 4,192 3 3.8 2 10.5 27 3.9 2,220 3 3.8 2 7.9 27 2.5 2,220 3 3.8 2 5.2 15 1.1 2,000 3 3.8 2 3.7 15 0.8 2,000 3 3.8 2 - 325 -7. Lime System Pumps In c l u d e s pump and d r i v e r . DRIVER Q TDH POWER MAT'L COST (L/S) (m) (kW) ($) 11 6 1.0 2,190 5 10 0.7 2,190 5.6 6 0.5 1,882 4 6 0.4 1,882 3.8 6 0.4 1,882 1.8 10 0.3 1,882 4 3 0.2 1,882 3.1 3 0.2 1,882 0.9 10 0.2 1,882 0.7 10 0.2 1,882 1.0 3 0.1 1,800 0.6 3 0.1 1,400 0.4 6 0.1 1,400 0.4 3 0.1 1,400 0.08 10 0.1 1,400 BULK SOURCE FACTOR SOURCE 3 3.8 2 3 3.8 2 3 3.8 2 3 3.8 2 3 3.8 2 3 3.8 2 3 3.8 2 3 3.8 2 3 3.8 2 3 3.8 2 3 3.8 2 3 3.8 2 3 3.8 2 3 3.8 2 3 3.8 2 8. Lime Feeder and S l u r r y Mix System I n c l u d e s dry chemical feeder, mix tank, mix tank mixer, s l u r r y d i s t r i b u t i o n pumps, and a s s o c i a t e d c i v i l , e l e c t r i c a l , p i p i n g and i n s t r u m e n t a t i o n b u l k s . C a p a c i t y - 38 kg Lime/hr M a t e r i a l Cost - $34,204 - Source 3 I n s t a l l a t i o n Manhours - 36 - Source 3 9. Submersible Pumps Inc l u d e s pump and d r i v e r . o TDH DRIVER POWER MAT'L COST SOURCE BULK FACTOR SOURCE (L/S) (m) (kW) ($) 246 6 21 15,000 5 3.8 2 5.8 7 0.6 2,500 5 3.3 2 10. Mixers DRIVER POWER MAT'L COST SOURCE BULK FACTOR SOURCE (kW) ($) 2.4 3,500 5 1.34 5 1.2 2,000 5 1.34 5 0.73 1,691 3 1.34 5 0.64 1, 691 3 1.34 5 0.50 1,458 3 1.34 5 0.44 1,275 3 1.34 5 0.30 1,275 3 1.34 5 0.25 1,275 3 1.34 5 0.20 1,275 3 1.34 5 0.10 1, 275 3 1. 34 5 <0.07 904 3 1.34 5 11. Dry Chemical Feeders CHEMICAL THROUGHPUT MAT'L COST SOURCE BULK FACTOR SOURCE (kg/hr) ($) 771 18,000 6 1.23 6 612 16,000 6 1.23 6 455 13,000 6 1.23 6 96 5,157 6 1.23 6 - 328 -12. T u r b o r a t o r s DRIVER BULK POWER MAT'L COST SOURCE FACTOR SOURCE (kW) ($) 3.7 7;000 7 1.8 5.6 9,000 7 1.8 13. D i s s o l v e d A i r F l o t a t i o n U n i t s I n c l u d e s skimmer mechanism, r e c y c l e pumps, compressor, p i p i n g , c o n t r o l panel and p i p i n g . Does not i n c l u d e c o n c r e t e tank. BULK AREA MAT'L COST SOURCE FACTOR SOURCE (m2) ($) 167 125,000 8 1.6 2 51 90,000 8 1.6 2 - 329 -14. Mix Tanks I n c l u d e s s t e e l tank, foundations, s t r u c t u r a l s t e e l , e l e c t r i c a l and i n s t r u m e n t a t i o n . Does not i n c l u d e mixers. VOLUME MAT'L COST SOURCE BULK FACTOR SOURCE (m3) ($) 17.9 12,530 2 4.0 2 5.8 9,100 2 5.2 2 4.8 8,640 2 5.3 2 3.2 7,680 2 5.7 2 2.2 6,020 2 6.0 2 1.7 5,100 2 6.0 2 1.2 3,600 2 6.0 2 0.3 648 2 6.0 2 0.2 384 2 6.0 2 - 330 -15. Dry Chemical Storage S i l o s I n c l u d e s s t e e l s i l o , f oundations, s t r u c t u r a l s t e e l , i n s t r u m e n t a t i o n and epoxy l i n e r . BULK VOLUME MAT'L COST SOURCE FACTOR SOURCE (m3) ($) 305 58,000 2 2.2 2 203 36,540 2 2.4 2 180 35,280 2 2.4 2 113 20,500 2 2.4 2 24 5,462 2 3.0 2 10 3,130 2 3.0 2 16. Storage Tanks I n c l u d e s carbon s t e e l tank, f o u n d a t i o n s , i n s t r u m e n t a t i o n and epoxy l i n e r . - 331 -BULK VOLUME MAT'L COST SOURCE FACTOR SOURCE (m 3) <$> 308 46,200 2 2.1 2 163 35,000 2 2.6 2 117 32,892 2 3.1 2 109 30,463 2 3.1 2 76 19,952 2 3.2 2 30 8,400 2 3.2 2 17. Mechanical A e r a t o r D i s m a n t l i n g Manhours - 72 Source - 3 B. PIPING 1. Carbon S t e e l / F i e l d F a b r i c a t e d I n c l u d e s supply and i n s t a l l a t i o n o f a l l p i p e , v a l v e s and f i t t i n g s . P r i c e s i n c l u d e an allowance f o r a standard number of v a l v e s and f i t t i n g s per u n i t l e n g t h of p i p e . - 332 -PIPE DIAMETER (mm) 50 75 100 150 200 250 300 400 450 MAT'L COST ($/M) 76.9 90.5 104.1 131.3 158.5 185.7 212.9 267.3 294.5 SOURCE 2 2 2 2 2 2 2 2 2 LABOUR PRODUCTIVITY (mh/m) 4.11 4.29 4.47 4.83 5.19 5.55 5.91 6. 63 6.99 SOURCE 2 2 2 2 2 2 2 2 2 2. Gate V a l v e s (ANSI 150#, Carbon S t e e l ) PIPE DIAMETER (mm) 100 MAT'L COST ($) 439 SOURCE 10 LABOUR PRODUCTIVITY (mh) 6.7 SOURCE 3. Flanges (ANSI 150# RFWN, Carbon S t e e l ) PIPE DIAMETER (mm) 100 MAT'L COST ($) 13.05 ea. SOURCE 10 LABOUR PRODUCTIVITY (mh) 3.5 ea. SOURCE - 333 -C. CIVIL 1. E x c a v a t i o n I n c l u d e s e x c a v a t i o n f o r foundations, underground p i p i n g , t h i c k e n e r / c l a r i f i e r tanks and t u n n e l s . Allowances f o r equipment r e n t a l c o s t s are f a c t o r e d i n t o t h e l a b o u r p r o d u c t i v i t y . M a t e r i a l Cost - N/A 3 Labour P r o d u c t i v i t y - 0.20 mh/m Source - 1 2. Common B a c k f i l l I n c l u d e s b a c k f i l l and compaction of excavated m a t e r i a l from 1. Allowances f o r equipment r e n t a l c o s t s are f a c t o r e d i n t o the l a b o u r p r o d u c t i v i t y . M a t e r i a l Cost - N/A 3 Labour P r o d u c t i v i t y - 0.20 mh/m Source - 1 3. G r a n u l a r B a c k f i l l I n c l u d e s supply, placement and compaction o f g r a n u l a r m a t e r i a l . - 334 -M a t e r i a l Cost - $9.00/m , . 3 Labour P r o d u c t i v i t y - 0.20 mh/m Source - 1 4. T o p s o i l S t r i p p i n g TIC - $0.65/m3 Source - 9 5. C l e a r i n g and Grubbing TIC - $0.51/m3 Source - 9 6. Dykes, Berms and Clay L i n e r s I n c l u d e s supply, placement and compaction o f impermeable m a t e r i a l . TIC - $5.00/m3 Source - 1 - 335 -7. R e i n f o r c e d Concrete I n c l u d e s formwork, r e i n f o r c i n g s t e e l , c o n c r e t e , placement and f i n i s h i n g . M a t e r i a l Cost - $275/m 3 Labour P r o d u c t i v i t y - 9.5 mh/m Source - 1 8. Concrete Paving I n c l u d e s formwork, wire mesh, conc r e t e , placement and f i n i s h i n g . 3 M a t e r i a l Cost - $250/m 3 Labour P r o d u c t i v i t y - 4.6 mh/m Source - 1 9. Pre-Engineered B u i l d i n g s I n c l u d e s metal c l a d b u i l d i n g complete w i t h foundations and f l o o r s l a b . Eave h e i g h t t o 8.0m. TIC - $430/m3 f l o o r area Source - 1 D. ELECTRICAL 1. Area L i g h t i n g I n c l u d e s l i g h t standards and a s s o c i a t e d power supply f o r e x t e r i o r l i g h t i n g . M a t e r i a l Cost - $41/m2 2 Labour P r o d u c t i v i t y - 1.6 mh/m Source - 1 E. INSTRUMENTATION AND CONTROL 1. Flow Meters ( O r i f i c e Meters) PIPE LABOUR DIAMETER MAT'L COST SOURCE PRODUCTIVITY SOURCE (mm) ($) (mh) 150 500 11 11 2 100 400 11 11 2 2. Flow T r a n s m i t t e r s ( E l e c t r o n i c D i f f e r e n t i a l P r e s s u r e T r a n s m i t t e r s ) M a t e r i a l Cost - $1500. each Source - 11 Labour P r o d u c t i v i t y - 11 mh's each Source - 2 3. Flow Recorders (Panel Mounted) M a t e r i a l Cost - $2000. each Source - 11 Labour P r o d u c t i v i t y - 12 mh's each Source - 2 4. Flow C o n t r o l V a l v e s I n c l u d e s carbon s t e e l b u t t e r f l y v a l v e w i t h t h r o t t l i n g e l e c t r o n i c a c t u a t o r . PIPE LABOUR DIAMETER MAT'L COST SOURCE PRODUCTIVITY SOURCE (mm) ($) (mh) 75 1,500 12 10 2 100 1,800 12 14 2 150 2,900 12 18 2 - 338 -5. M i c r o p r o c e s s o r Based C o n t r o l l e r s DESCRIPTION MAT'L COST ($/M) 1 Loop, 2,000 - Analog Inputs, - Analog Outputs 4 Loop, 5,000 8 Analog Inputs, 4 Analog Outputs V a r i a b l e 2,000 Frequency SOURCE 12 12 12 LABOUR PRODUCTIVITY (mh/m) 71 177 71 SOURCE 12 12 12 6. ORP Probes M a t e r i a l Cost - $1,000. each Bulk F a c t o r - 2.1 Source - 12 7. ORP Recorders ( i n c l u d e s t r a n s m i t t e r ) M a t e r i a l Cost - $350. each Bulk F a c t o r - 2.1 Source - 12 - 339 -8. DO Probes ( i n c l u d e s t r a n s m i t t e r ) M a t e r i a l Cost - $3,500. each Bulk F a c t o r - 2.1 Source - 12 - 340 -SOURCES 1. P e r s o n a l communication, D. D i c a i r e , JODA E n t e r p r i s e s , Vancouver, B.C., March 1988 2. Unpublished h i s t o r i c a l data, 1985 3. Richardson's Rapid E s t i m a t i n g , 1986 4. P e r s o n a l communication, G. Teichroeb, Chamco I n d u s t r i e s , Vancouver, B.C., March 1988 5. P e r s o n a l communication, A. Racine, F l y g h t Canada, Vancouver, B.C., January 1988 6. P e r s o n a l communication, D. Skeath, UKAF I n d u s t r i e s , Vancouver, B.C., March 1988 7. P e r s o n a l communication, C. G u a r n a s c h e l l i , T u r b o r a t o r Technology Inc., Vancouver, B.C., March 1988 8. Pe r s o n a l Communication, N. Vancouver, B.C., A p r i l 1988 K i r k , Rexnord Canada, - 341 -9. R.S. Means Company, Inc., "Means Heavy C o n s t r u c t i o n Cost Data", 1987 10. P e r s o n a l communication, Westlund I n d u s t r i a l Supply, Vancouver, B.C., March 1988 11. P e r s o n a l communication, H. H i l l , F i s c h e r and P o r t e r (Canada) L t d . , Vancouver, B.C., February 1988 

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