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Physical-chemical treatment and disinfection of a landfill leachate Bjorkman, Victor B. 1979

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P H Y S I C A L - C H E M I C A L T R E A T M E N T AND D I S I N F E C T I O N OF A L A N D F I L L L E A C H A T E b y V i c t o r B . B j o r k m a n B . A . S c . , 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 , 1 9 5 1 A T H E S I S S U B M I T T E D I N P A R T I A L F U L F I L L M E N T OF T H E R E Q U I R E M E N T S FOR T H E D E G R E E OF M A S T E R OF A P P L I E D S C I E N C E i n T h e F a c u l t y of G r a d u a t e S t u d i e s C T h e D e p a r t m e n t of C i v i l E n g i n e e r i n g ) We a c c e p t t h i s t h e s i s a s c o n f o r m i n g t o t h e r e q u i r e d s t a n d a r d s T H E U N I V E R S I T Y OF M a y , V i c t o r B e r n h a r d B R I T I S H C O L U M B I A 1979 B j o r k m a n In p r esenting t h i s t h e s i s i n p a r t i a l f u l f i l l m e n t of the requirements f o r an advanced degree at the U n i v e r s i t y of B r i t i s h Columbia, I agree that the L i b r a r y s h a l l make i t f r e e l y a v a i l a b l e f o r reference and study. I f u r t h e r agree that permission f o r extensive copying of t h i s t h e s i s f o r s c h o l a r l y purposes may be granted by the Head of my Department or h i s representatives. I t i s understood that copying or p u b l i c a t i o n of t h i s t h e s i s f o r f i n a n c i a l g a in s h a l l not be allowed without my permission. Department of C i v i l Engineering The U n i v e r s i t y of B r i t i s h Columbia 2075 Westbrook Place Vancouver, B r i t i s h Columbia V6T 1W5 Canada V i c t o r B. Bjorkman i i A B S T R A C T W a t e r , f l o w i n g t h r o u g h b e d s o f r e f u s e i n a s a n i t a r y l a n d f i l l , w i l l l e a c h o r g a n i c a n d i n o r g a n i c s u b s t a n c e s f r o m t h e f i l l . T h e s e l e a c h e d s u b s t a n c e s m a y b e a s o u r c e o f p o l l u t i o n f o r r e c e i v i n g s u r f a c e o r g r o u n d w a t e r s . T h e l e a c h a t e , b e f o r e i t i s d i l u t e d b y t h e r e c e i v i n g w a t e r , c a n u s u a l l y b e c l a s s e d a s a v e r y s t r o n g w a s t e w a t e r ; t h a t i s , t h e l e v e l s o f t h e w a s t e w a t e r p a r a m e t e r s C O D , S u s p e n d e d S o l i d s , l o w d i s s o l v e d o x y g e n a n d t u r b i d i t y a r e m a n y t i m e s t h o s e f o u n d i n n o r m a l , m u n i c i p a l w a s t e w a t e r . A d d e d t o t h e s e f o r e g o i n g p a r a m e t e r s a r e p o s s i b l e h i g h l e v e l s o f t o x i c c h e m i c a l s a n d m e t a l s . I t i s n o w g e n e r a l l y r e c o g n i z e d t h a t t h e l e a c h a t e f r o m r e f u s e l a n d f i l l s s h o u l d b e c o n t r o l l e d , a n d i n s o m e r e c e n t l y d e s i g n e d l a n d f i l l s , l e a c h a t e c o l l e c t i o n i s i n c o r p o r a t e d i n t o t h e o v e r a l l d e s i g n . T o x i c c h e m i c a l s a n d m e t a l s a r e n o t a d e q u a t e l y r e m o v e d f r o m w a s t e w a t e r s b y t h e s t a n d a r d b i o l o g i c a l s e w a g e t r e a t m e n t p r o c e s s e s ; t h u s , t h e c o l l e c t e d l a n d f i l l l e a c h a t e o f t e n r e q u i r e s p r e t r e a t m e n t b e f o r e i t c a n b e d i s c h a r g e d t o a m u n i c i p a l s e w e r s y s t e m . I f i t i s t o b e d i s c h a r g e d t o a n a t u r a l r e c e i v i n g w a t e r , i t r e q u i r e s m o r e c o m p l e t e t r e a t m e n t . I t w a 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 t o a t t e m p t t o d e v e l o p a p h y s i c a l - c h e m i c a l t r e a t m e n t s y s t e m f o r l a n d f i l l l e a c h a t e , s u c h t h a t t h e e f f l u e n t m i g h t b e s a f e l y d i s c h a r g e d t o a b i o l o g i c a l t r e a t m e n t p l a n t o r a n a t u r a l r e c e i v i n g w a t e r . T o d e a l w i t h t h e e x t r e m e l y l a r g e n u m b e r o f p o s s i b l e c h e m i c a l r e a g e n t s , a n d t o a l e s s e r e x t e n t , p h y s i c a l m e t h o d s a v a i l a b l e - , i t w a s f i r s t n e c e s s a r y t o s e l e c t a n u m b e r o f p r i m a r y c a n d i d a t e s f r o m p r i o r i n f o r m a t i o n a n d t h e o r y a v a i l a b l e i n t h e l i t e r a t u r e ; s e c o n d l y , i t w a s a d v a n t a g e o u s t o u s e a s t a t i s t i c a l l y d e s i g n e d e x p e r i m e n t a l p r o g r a m m e f o r s c r e e n i n g t h o s e c a n d i d a t e s c h o s e n . I n t h e s c r e e n i n g p r o c e s s , n o c h a n g e s i n t h e p h y s i c a l p a r a m e t e r s s c r e e n e d , s u c h a s d u r a t i o n a n d s p e e d o f m i x i n g o r d u r a t i o n o f s e t t l i n g , w e r e f o u n d t o b e s i g n i f i c a n t , i f n o r m a l m i n i m u m t i m e s a n d u s u a l s p e e d s w e r e u s e d . F o u r c h e m i c a l r e a g e n t s , l i m e , o z o n e , f e r r i c s u l f a t e , a n d a l u m w e r e i n d i c a t e d a s h a v i n g a p o t e n t i a l l y s i g n i f i c a n t e f f e c t o n t h e l e a c h a t e -c o n t a i n e d T o t a l S o l i d s ( T S ) , T o t a l C a r b o n ( T C ) , T u r b i d i t y ( T u r b ) , C a d m i u m ( C d ) , C o p p e r ( C u ) , I r o n ( F e ) , Z i n c ( Z n ) , P o t a s s i u m ( K ) , C a l c i u m ( C a ) , S o d i u m ( N a ) , P h o s p h o r u s a n d t h e a c i d - b a s e r e l a t i o n s h i p a s e x p r e s s e d b y t h e t e r m p H . T h e f o l l o w - u p e x p e r i m e n t s d e t e r m i n e d t h a t o n l y t w o o f t h e a b o v e f o u r r e a g e n t s w e r e s i g n i f i c a n t l y e f f e c t i v e i n r e m o v a l o f t h e a f o r e - n a m e d p o l l u t a n t s , a s w e l l a s M a n g a n e s e ( M n ) , L e a d ( P b ) , C o l o u r , C h e m i c a l O x y g e n D e m a n d ( C O D ) , t h e c o m p o n e n t s o f T o t a l C a r b o n ( T C ) T o t a l I n o r g a n i c C a r b o n ( T I C ) a n d T o t a l O r g a n i c C a r b o n ( T O C ) , a n d t h e c o m p o n e n t s o f T o t a l S o l i d s ( T S ) — S u s p e n d e d S o l i d s ( S S ) a n d D i s s o l v e d S o l i d s ( D S ) . A l l o f t h e m u l t i v a l e n t m e t a l s , e x c e p t C a l c i u m , w e r e s i g n i f i c a n t l y r e m o v e d f r o m t h i s w a s t e w a t e r b y p H a d j u s t m e n t w i t h l i m e , w i t h a d d i t i o n a l m i n o r r e m o v a l s b y o x i d a t i o n w i t h o z o n e . D i s s o l v e d o r g a n i c m a t e r i a l s w e r e n o t r e m o v e d b y p H a d j u s t m e n t a n d o n l y r e m o v e d i n a p p r o x i m a t e s t o i c h i o m e t r i c a m o u n t s b y r e a c t i o n w i t h o z o n e . I n t h e s e e x p e r i m e n t s , t h e p o l y m e r s t e s t e d w e r e n o t e f f e c t i v e i n t h e r e m o v a l o f t h e n a m e d p o l l u t a n t s . O z o n e i s i n d i c a t e d t o b e a n e f f e c t i v e d i s i n f e c t a n t , b u t h i g h l y s e n s i t i v e t o t h e COD o f t h e l e a c h a t e . A n o z o n e - C O D r a t i o , w h i c h d e t e r m i n e s t h e q u a n t i t y o f a p p l i e d o z o n e n e c e s s a r y f o r t h e o x i d a t i o n o f s o m e o f t h e d i s s o l v e d m e t a l s a n d f o r d i s i n f e c t i o n , a s a f u n c t i o n o f t h e c o n t a i n e d C O D , i s p r o p o s e d f o r t h i s l e a c h a t e . T h e p o s s i b i l i t y o f t h e a p p l i c a t i o n o f t h i s o z o n e - C O D r a t i o i s p u t f o r t h , s u b j e c t t o f u r t h e r i n v e s t i g a t i o n . V TABLE OF CONTENTS ABSTRACT t i i LIST OF TABLES' v i i i LIST OF FIGURES x i ACKNOWLEDGEMENT x i i i Chapter 1 INTRODUCTION 1 1.1 The San i t a r y L a n d f i l l 1 1.2 L a n d f i l l Leachate 1 1.3 Leachate Production 2 1.4- E f f e c t of Leachate on Receiving Environment 2 1.5 The Character of Leachate 3 1.6 Purpose of This Research P r o j e c t 3 2 LITERATURE REVIEW AND EXPERIMENTAL DESIGN 10 2.1 Previous Research on the Treatment of L a n d f i l l Leachate 10 2.2 Experimental Programme 12 3 . GENERAL-REVIEW OF PHYSICAL CHEMICAL PROCESSES 14 3.1 General Process D e s c r i p t i o n 14 3.2 P h y s i c a l Unit Processes 14 3.3 Chemical Unit Processes 14 3.4 Advantages and Disadvantages of Physical-Chemical Processes 15 4„ SELECTION OF REAGENT AND PROCESS CANDIDATES 17 4.1 D i v i s i o n of the Experimental Programme i n t o Two Phases 17 v i 4.2 Chemical Reagents 17 4.3 P h y s i c a l Unit Operations Screened 18 5 EXPERIMENTAL DESIGN 20 5.1 S t a t i s t i c a l F a c t o r i a l Design 20 5.2 F r a c t i o n a l F a c t o r i a l Design 20 5.3 C a l c u l a t i o n of E f f e c t s 24 5.4 C a l c u l a t i o n of the Standard D e v i a t i o n 26 5.5 Determining the S i g n i f i c a n t E f f e c t s 28 6 EXPERIMENTAL APPARATUS AND ANALYTICAL METHODS 42 6.1 Ozone Generating and Contact System 42 6.2 P h y s i c a l Unit Processes Simulation 44 6.3 A n a l y t i c a l Methods 45 6.4 D i s i n f e c t i o n w i t h Ozone • 46 6.5 Ozone D i s i n f e c t i o n Procedure 47 7 PRESENTATION AND DISCUSSION OF DATA 48 7.1 D a t a — S c r e e n i n g Experiments 48 7.2 D i s c u s s i o n of Screening Data 48 7.3 Post-Screening Experimental Data 50 7.4 Di s c u s s i o n of Post-Screening Data 72 7.5 Data—Ozone D i s i n f e c t i o n 77 7.6 D i s c u s s i o n of D i s i n f e c t i o n Data 77 7.7 General D i s c u s s i o n 80 7.8 A p p l i c a t i o n of Results to P r e d i c t Ozone Requirements . 83 7.9 Cost Considerations 89 8 CONCLUSIONS AND RECOMMENDATIONS 91 8.1 Conclusions 91 v i i 8 . 2 R e c o m m e n d a t i o n s 9 2 9 L I S T OF R E F E R E N C E S 9 5 1 0 A P P E N D I C E S G e n e r a l B i b l i o g r a p h y 9 8 R a w D a t a 9 9 v i i i LIST OF TABLES TABLE 1 LIMITS FOR EFFLUENT PARAMETERS THAT MAY BE OF CONCERN IN SPECIFIC DISCHARGE 4 2 RECEIVING WATER QUALITY MAINTENANCE OBJECTIVES . . . . 6 3 TYPICAL COMPOSITION OF LEACHATES 9 4 TREATMENT VARIABLES SCREENED AND APPLIED LEVELS OF EACH CORRESPONDING TO "HIGH" AND "LOW" LEVELS INDICATED IN SCREENING DESIGN MATRIX OF TABLE 5 19 5 PLACKET-BURMAN DESIGN FOR DETERMINING THE EFFECT OF 15 VARIABLES, AT 2 LEVELS EACH, USING 16 RUNS 22 6 POLLUTANTS MEASURED IN THE SCREENING PROCESS . . . . 23 7 FOUND VALUES OF THE POLLUTANTS MEASURED IN THE SCREENING EXPERIMENTS 25 8 COMPILATION OF STATISTICALLY SIGNIFICANT EFFECTS FOR VARIABLES OF SCREENING EXPERIMENTS 41 9 COMPILATION OF REAGENT DOSING LEVELS FOR GROUPS 1, 2 AND 3 WITH SIGNIFICANT POLLUTING CHARACTERISTICS SHOWN WHERE APPLICABLE 52 10 COMPILATION OF REAGENT DOSING LEVELS FOR GROUPS 4, 5 AND 6 WITH SIGNIFICANT POLLUTING CHARACTERISTICS SHOWN WHERE APPLICABLE 53 11 COMPILATION OF REAGENT DOSING LEVELS FOR GROUPS 7, 8 AND 9 WITH SIGNIFICANT POLLUTING CHARACTERISTICS SHOWN WHERE APPLICABLE 54 12 COMPILATION OF REAGENT DOSING LEVELS FOR GROUPS 10 AND 11 O i x WITH SIGNIFICANT POLLUTING CHARACTERISTICS SHOWN WHERE APPLICABLE 55 13 COMPILATION OF REAGENT DOSING LEVELS FOR GROUP 12, RUNS 101-104 56 14 NAME CODES FOR THE INDEPENDENT VARIABLES FOR THE POST-SCREENING EXPERIMENTS (.GROUPS 2-12) 57 15 REMOVAL OF SELECTED POLLUTANTS FROM LANDFILL LEACHATE IN EXPERIMENTAL GROUP 2, RUNS 17, 18, 20, 23, 27, 29, 30, 31, 32 58 16 REMOVAL OF SELECTED POLLUTANTS FROM LANDFILL LEACHATE IN EXPERIMENTAL GROUP 4, RUNS 37-52 59 17 REMOVAL OF SELECTED POLLUTANTS FROM LANDFILL LEACHATE IN EXPERIMENTAL GROUP 5, RUNS 53-56 60 18 REMOVAL OF SELECTED POLLUTANTS FROM LANDFILL LEACHATE IN EXPERIMENTAL GROUP 6, RUNS 57-61 61 19 REMOVAL OF SELECTED POLLUTANTS FROM LANDFILL LEACHATE IN EXPERIMENTAL GROUP 7, RUNS 57, 62-64 62 20 REMOVAL OF SELECTED POLLUTANTS FROM LANDFILL LEACHATE IN EXPERIMENTAL GROUP 8, RUNS 65-72 63 21 REMOVAL OF SELECTED POLLUTANTS FROM LANDFILL LEACHATE IN EXPERIMENTAL GROUP 9, RUNS 73-80 64 22 REMOVAL OF SELECTED POLLUTANTS FROM LANDFILL LEACHATE IN EXPERIMENTAL GROUP 10, RUNS 81-96 65 23 REMOVAL OF SELECTED POLLUTANTS FROM LANDFILL LEACHATE IN EXPERIMENTAL GROUP 11, RUNS 97-100 66 24 REMOVAL OF SELECTED POLLUTANTS FROM LANDFILL LEACHATE IN EXPERIMENTAL GROUP 12, RUNS 101-104 67 X 25 EXAMPLE OF A FACTORIAL DESIGN MATRIX USED IN THE POST-SCREENING EXPERIMENTS WITH THE MAIN EFFECTS AND THE INTERACTION EFFECTS CALCULATED FOR EACH OF THE FOUR TREATMENT VARIABLES USED IN GROUP 4 (EFFECT ON DEPENDENT VARIABLE—COLOUR) % 69 26 SUMMARY OF BEST LOW' RESIDUALS OBTAINED WITH'REAGENT DOSES AND DOSE RANGES AS INDICATED 78 27 STANDARD PLATE COUNTS AT 35°C FOR LEACHATE TREATED WITH OZONE (COD OF 14,300 irig/1) 79 x i LIST OF FIGURES FIGURE 1 HALF-NORMAL PLOT OF THE SCREENING DATA FOR TURBIDITY WITH RELATED TABULATED EXAMPLE OF THE STANDARD DEVIATION CALCULATION 27 2 HALF-NORMAL PLOT OF THE SCREENING DATA FOR pH WITH RELATED TABULATED EXAMPLE OF THE STANDARD DEVIATION CALCULATION 30 3 HALF-NORMAL PLOT OF THE SCREENING DATA FOR TOTAL CARBON WITH RELATED TABULATED EXAMPLE OF THE STANDARD DEVIATION CALCULATION 31 4 HALF-NORMAL PLOT OF THE SCREENING DATA FOR PHOSPHORUS WITH RELATED TABULATED EXAMPLE OF THE STANDARD DEVIATION CALCULATION 32 5 HALF-NORMAL PLOT OF THE SCREENING DATA FOR TOTAL SOLIDS WITH RELATED TABULATED EXAMPLE OF THE STANDARD DEVIATION CALCULATION . . . 33 6 HALF-NORMAL PLOT OF THE SCREENING DATA FOR CADMIUM WITH RELATED TABULATED EXAMPLE OF THE STANDARD DEVIATION CALCULATION 34 7 HALF-NORMAL PLOT OF THE SCREENING DATA FOR COPPER WITH RELATED TABULATED EXAMPLE OF THE STANDARD DEVIATION CALCULATION 35 8 HALF-NORMAL PLOT OF THE SCREENING DATA FOR ZINC WITH RELATED TABULATED EXAMPLE OF THE STANDARD DEVIATION CALCULATION 36 x i i 9 HALF-NORMAL PLOT OF THE SCREENING DATA FOR CALCIUM WITH RELATED TABULATED EXAMPLE OF THE STANDARD DEVIATION CALCULATION 37 10 HALF-NORMAL PLOT OF THE SCREENING DATA FOR POTASSIUM WITH RELATED TABULATED EXAMPLE OF THE STANDARD DEVIATION CALCULATION 38 11 HALF-NORMAL PLOT OF THE SCREENING DATA FOR SODIUM WITH RELATED TABULATED EXAMPLE OF THE STANDARD DEVIATION CALCULATION 39 12 HALF-NORMAL PLOT OF THE SCREENING DATA FOR IRON WITH RELATED TABULATED EXAMPLE OF THE STANDARD DEVIATION CALCULATION 40 13 SCHEMATIC OF OZONATING SYSTEM 43 14 EXAMPLE OF THE HALF-NORMAL PLOT OF THE ABSOLUTE VALUES OF THE CALCULATED DEPENDENT VARIABLE EFFECTS ON COLOUR WITH THE RELATED STANDARD DEVIATION CALCULATION 71 15 CHART FOR ESTIMATING OZONE DOSE REQUIRED TO OXIDIZE CERTAIN METALLIC IONS AND LIVING ORGANISMS 88 x i i i ACKNOWLEDGMENT The author g r a t e f u l l y acknowledges the guidance, a s s i s t a n c e and i n t e r e s t of h i s Supervisor, Dr. D. S. Mavinic. Acknowledgment i s a l s o made of the h e l p f u l advice r e c e i v e d from Dr. W. K. Oldham and Dr. R. D. Cameron. Much a s s i s t a n c e was r e c e i v e d from Mrs. E l i z a b e t h McDonald, Mary Mager and Susan Harper of the C i v i l Engineering E n v i r o n -mental Laboratory. F i n a n c i a l support f o r t h i s work o r i g i n a t e d from the Na t i o n a l Research C o u n c i l of Canada. CHAPTER 1 INTRODUCTION 1 . 1 The S a n i t a r y L a n d f i l l The s a n i t a r y l a n d f i l l technique i s c u r r e n t l y the most widely used s o l i d waste d i s p o s a l method. The predominant use of the s a n i t a r y l a n d f i l l i s based on i t s a c c e p t a b i l i t y , measured i n the combined terms of time and volume e f f e c t i v e n e s s , nuisance abatement and c o s t . The i n c r e a s i n g volumes of s o l i d waste being generated today, c o n t a i n i n g more and more compounded m a t e r i a l s o f great complexity, introduce new problems f o r l a n d f i l l s o l i d waste d i s p o s a l . B a s i c a l l y , a s a n i t a r y l a n d f i l l i s a land area where s o l i d waste i s deposited, compacted f o r volume r e d u c t i o n , and then the d e p o s i t i o n i s covered w i t h earth at r e g u l a r time and space i n t e r v a l s . Notwithstanding the simple d e s c r i p t i o n of the s a n i t a r y l a n d f i l l 'process, there are a number of a s s o c i a t e d problems which can only be over-come by proper design, e f f i c i e n t o p e r a t i o n , and c o n t r o l of a l l of the products of decomposition generated from the s o l i d waste. 1 . 2 L a n d f i l l Leachate P o s s i b l y the most se r i o u s problem caused by deposited s o l i d waste i n a l a n d f i l l i s the production of g r o s s l y p o l l u t e d l i q u i d s from the extraneous water e n t e r i n g and passing through the l a n d f i l l . The water e n t e r i n g the l a n d f i l l forms s o l u t i o n s of the anaerobic decomposition 2 products of the s o l i d waste i n the l a n d f i l l , and these s o l u t i o n s , generally-termed "leachates," contain both dissolved and suspended p o l l u t i n g substances. 1.3 Leachate Production L a n d f i l l leachate i s only produced when there i s more water entering the l a n d f i l l than i s required to saturate the mass of the deposited s o l i d waste. A desired function of the sanitary l a n d f i l l i s the e f f e c t i v e s t a b i l i z a t i o n of the organic putrescibles i n the deposited s o l i d waste; t h i s s t a b i l i z a t i o n i s expedited i n a moist-to-wet environment. T o t a l l y preventing i n f i l t r a t i o n of water into the l a n d f i l l would be c o s t l y and counter-productive to the s t a b i l i z a t i o n process (1). Recognizing that i t may not be p r a c t i c a l or desirable to l i m i t a l l leachate production, i t becomes necessary to both c o l l e c t and manage the produced leachate, so that the harm caused to a r e c e i v i n g environment may be minimized. 1.4- E f f e c t of Leachate on a Receiving Environment The " i n s u l t " caused to a r e c e i v i n g environment by l a n d f i l l leachate i s widely discussed i n the l i t e r a t u r e (2, 3). Q u a l i t a t i v e and quantitative l i m i t s on s p e c i f i e d pollutants have been set by many governmental regulatory agencies. Tables 1 and 2 are examples of regulating l i m i t s and are those set by the P o l l u t i o n Control Board of the Province of B r i t i s h Columbia (4-). 3 1.5 The Character of Leachate The character of leachate has been described by many i n v e s t i g a t o r s ( 2 , 3, 5). Table 3 d i s p l a y s a range of values of s e l e c t e d leachate p o l l u t a n t s as given by some of these i n v e s t i g a t o r s . 1.6 The Purpose of This Research P r o j e c t The purpose of t h i s research p r o j e c t was t o evaluate the e f f e c t i v e n e s s of c e r t a i n s e l e c t e d chemicals, combined with p h y s i c a l separation processes, t o remove p o l l u t a n t s from l a n d f i l l l e a c h a t e ; i t was a l s o decided t o evaluate ozone, both as a p o l l u t i o n removal chemical and as an a l t e r n a t e d i s i n f e c t i o n medium. 4 TABLE 1 LIMITS FOR EFFLUENT PARAMETERS THAT MAY BE OF CONCERN IN SPECIFIC DISCHARGE (1)* (Ref. 4, Tab. 5-2) Maximum Concentration (2)* Parameter mg/1 (except pH and TI^) Level AA Level BB Methylene Blue Active Substances 5 -O i l and Grease 15 30 pH 6.5-8.5 6.5-8.5 Phenol 0.2 0.4 TL m(96 hr.) (3) 100% 75% Aluminum (Total) 2.0 •4.0 Arsenic (Total) 0.05 0.25 Barium (Dissolved) 1.0 1.0 Boron (Dissolved) 5 5 Cadmium (Dissolved) 0.005 0.01 Chromium (Total) 0.1 0.3 Cobalt (Dissolved) 0.1 0.5 Copper (Dissolved) 0.2 0.5 Cyanide (Total) 0.1 0.5 Fluoride (Dissolved) 5 -Iron (Dissolved) 0.3 1.0 Lead (Total) 0.05 0.1 Manganese (Dissolved) 0.05 0.5 Mercury (Total) 0.0006 0.002 Molybdenum (Total) 0.2 0.5 Nickel (Dissolved) 0.3 0.5 Nitrogen (4) - -Resin Acid Soaps 5 -Selenium (Total) 0.05 0.1 S i l v e r (Total) 0.1 1.0 Sulphate (Dissolved)(5) 50 250 Sulphide (Dissolved) 0.5 1.0 Tin (Total) 5 10 Zinc (Total) 0.5 5.0 * Bracketed numbers r e f e r to Appendix to Table 1 which follows. 5 APPENDIX TO TABLE 1 Explanatory Notes 1. The l i m i t s apply to discharges to a l l r e c e i v i n g waters and to ground unless otherwise noted. However, a l i m i t w i l l only be shown on a permit where investigations i n accordance with Section 5.12 indi c a t e t h i s i s needed. 2. Levels may be adjusted to take account of background l e v e l s i n the  water supply. Other parameters may be added at the d i s c r e t i o n of the Director. 3. TL^^S hr.) samples to be p r i o r to c h l o r i n a t i o n . 4. A l i m i t a t i o n on nitrogen may be required where s i t e - s p e c i f i c studies indicate nitrogen to be a c o n t r o l l i n g f a c t o r f o r eutrophication or where the nitrogen l e v e l of the e f f l u e n t i s considered to be abnormally high. 5. Applies to freshwater only. 6 TABLE 2 RECEIVING WATER QUALITY MAINTENANCE OBJECTIVES (1)* (Ref. 4, Tab. 5-3) PARAMETER OBJECTIVE Dissolved Oxygen Decrease not to exceed 10% Residual Chlorine Below detectable l i m i t s (amperometric method) Nutrients No detectable increase i n s i t e s p e c i f i c p r o d u c t i v i t y - l i m i t i n g parameters (2)" (5)* Coliforms-receiving waters - s h e l l f i s h meat (3)* (3)* T o x i c i t y No increase above background (4-)* Settleable Solids N e g l i g i b l e increase Floatable Solids and Scum Negligi b l e increase O i l None v i s i b l e on water surface Organisms No change i n p r o d u c t i v i t y or development of nuisance conditions (5)* Heavy Metals Neglig i b l e increase * Bracketed numbers r e f e r to Appendix to Table 2 which follows. 7 APPENDIX TO TABLE 2 Explanatory Notes These objectives are f o r the maintenance of background r e c e i v i n g water q u a l i t y , generally expressed i n terms of the maximum allowable change f o r s p e c i f i e d parameters. They are not applicable within the i n i t i a l d i l u t i o n zone as defined i n t h i s document. Other discharges may be taken i n t o account i n determining whether the allowable maximum change i s to be less than any value given. Other parameters may be added by the Director. Limiting parameters w i l l normally be taken as phosphates and/or nitrogen forms. In general, t o t a l coliform l e v e l s are not to exceed a median MPN of 1000/100 ml or a f e c a l coliform median MPN of 200/100 ml and i n s h e l l f i s h waters are not to exceed a f e c a l coliform median MPN of 14/100 ml and s h e l l f i s h meats may not show a f e c a l coliform l e v e l greater than MPN of 230 per 100 gm. Reference may be made to B r i t i s h Columbia Health Branch "Recommended Water Quality Standards" and the "National S h e l l f i s h Sanitation Program Manual of Operation" published by the United States Department of Health, Education and Welfare. As measured i n a 96-hour TI^ s t a t i c bioassay t e s t . P r o d u c t i v i t y r e f e r s to b i o l o g i c a l parameters which are not amenable to tabulation; however, the following nuisance conditions are t y p i c a l of those to be considered: In freshwater lakes, presence of: a) massive growths of planktonic bluegreen algae (Cyanophyceae f o r more than 8 s e v e r a l days d u r a t i o n ; b) massive growths of attached filamentous diatoms ( B a c i l l a r i o p h y c e a e ) and/or rooted aquatic p l a n t s e s p e c i a l l y near the s h o r e l i n e . In r i v e r s and streams, presence of massive growths of attached green algae CChlorophyceae), filamentous diatoms ( B a c i l l a r i o p h y c e a e ) and/or rooted aquatic p l a n t s , slime-forming b a c t e r i a (as " S p h a e r o t i l u s " ) , sludge worms ( T u b i f i c i d a e ) or chironomids (Chironomidae). At sea or i n e s t u a r i e s , presence of sludge beds with reduced species d i v e r s i t y and a r e s t r i c t e d range of predominant organisms such as " C a p i t e l l a c a p i t a t a . " 9 TABLE 3 TYPICAL COMPOSITION OF LEACHATES (1, 5) T Parameter Range of Values or Concentration* PH 3.7 8.5 To t a l Carbon (TC) 715 28,000 Tot a l Organic Carbon (TOC) 256 28,000 Chemical Oxygen Demand (COD) 0 90,000 Calcium (Ca) 5 7,200 Cadmium (Cd) 0 17 Copper (Cu) 0 23.4 Iron (Fe) 0 5,500 Potassium (K) 2.8 3,770 Sodium (Na) 0 7,700 Phosphorus—Total (P) 0 130 Manganese (Mn) 0.06 1,558 Lead (Pb) 0 5 Zinc (Zn) 0 1,000 Tot a l Solids (TS) 584 45,000 Suspended Solids (SS) 10 16,800 Dissolved Solids (DS) 584 44,900 * A l l values except those f o r pH are i n Milligrams per L i t r e (mg/1). 10 CHAPTER 2 LITERATURE REVIEW AND EXPERIMENTAL DESIGN 2.1 Previous Research on Treatment of L a n d f i l l Leachate The ongoing research directed to l a n d f i l l leachate treatment, c a r r i e d on at the University of B r i t i s h Columbia ( l , 2, 3) and by others (5, 6, 7) demonstrates the d i f f i c u l t y of developing a u n i v e r s a l treatment f o r a l l l a n d f i l l leachate. The extreme v a r i a b i l i t y , i n both concentration and numbers of p o l l u t i n g constituents i n l a n d f i l l leachate, i s the p r i n c i p a l cause f o r the treatment d i f f i c u l t i e s ; to these d i f f i c u l t i e s must be added the problem of providing an adequate and nonpolluting d i s i n f e c t i o n step, to cope with the p o t e n t i a l f o r b a c t e r i a l and v i r a l contamination (8) of the l a n d f i l l leachate. Poorman (2) i n an i n v e s t i g a t i o n of anaerobic b i o l o g i c a l t r e a t -ment of l a n d f i l l leachate, found that with detention times of 5 to 20 days good removals of organics was p o s s i b l e ; but i n the case of the heavy metal p o l l u t a n t s , while the;."percentage reduction appeared r e l a t i v e l y high, the e f f l u e n t concentrations were s t i l l above acceptable l i m i t s (4). Lidkea (3) found, i n t r e a t i n g l a n d f i l l leachate with peat, that adsorption of metals on the peat was high up to the adsorption capacity of the peat f o r any p a r t i c u l a r metal, Uloth and Mavinic (1) treated leachate by an aerobic b i o l o g i c a l process and obtained r e s u l t s s i m i l a r to the Poorman (2) anaerobic study but also i d e n t i f i e d some i n h i b i t i o n of b i o l o g i c a l a c t i v i t y and a t t r i b u t e d 11 t h i s p a r t i a l l y to the heavy metal content. Corbett ( 9 ) , using a leachate w i t h lower concentrations of the p o l l u t i n g c o n s t i t u e n t s than are found i n most leachates, compared t r e a t i n g leachate by a d s o r p t i o n / f i l t e r i n g through peat and chemical treatment using lime and f e r r i c c h l o r i d e ; he found both t o be e f f e c t i v e f o r metal removal, w i t h no r e a l advantage i n combined chemical-peat treatment. Bioassays i n d i c a t e d t h a t t o x i c i t y to f i s h (rainbow t r o u t ) increased w i t h higher pH values. Thornton and Blanc ( .5) t r e a t e d leachate w i t h alum and l i m e , f i n d i n g that lime was much s u p e r i o r t o alum f o r metal removal but n e i t h e r gave s a t i s f a c t o r y removal of BOD or COD. Chian and De Walle ( 6 ) experimented w i t h b i o l o g i c a l and p h y s i c a l - c h e m i c a l treatments of leachate and concluded t h a t a combined p h y s i c a l - c h e m i c a l - b i o l o g i c a l system was re q u i r e d f o r proper leachate treatment. Boyle and Ram ( 7) conducted b i o l o g i c a l and p h y s i c a l - c h e m i c a l research on l a n d f i l l leachate and reported on removals of COD, I r o n , C h l o r i d e , T o t a l S o l i d s , pH, A l k a l i n i t y , Hardness and Color. The b i o l o g i c a l processes were more e f f e c t i v e f o r BOD and COD removals, whereas chemicals provided a b e t t e r removal of co l o u r and I r o n . C h l o r i n a t i o n i s the most widely used process f o r the d i s i n f e c t i o n of wastewater i n North America but t h i s process i s now being c r i t i c i z e d because of the p o s s i b l e r e a c t i o n between c h l o r i n e and the organics found i n leachate. I t has been reported (10) t h a t i t i s probable t h a t every conceivable chloro-organic r e a c t i o n occurs and th a t some of these r e a c t i o n s produce products t h a t are ca r c i n o g e n i c . Yao (11) examined the undesirable aspects of c h l o r i n a t i o n and the advantages of using ozone as a d i s i n f e c t a n t , but the use of ozone, as a d i s i n f e c t a n t of lea c h a t e s , i s j u s t now being researched. 12 2.2 Experimental Programme The experimental programme was designed such that the e f f e c t of each of the chemical reagents, and the p h y s i c a l s e p a r a t i o n methods t e s t e d , could be s t a t i s t i c a l l y evaluated, both as d i r e c t s i n g l e e f f e c t s and as combined i n t e r a c t i n g e f f e c t s . Several s e q u e n t i a l l y s i z e d reagent dose ranges were a p p l i e d , t o q u a n t i f y the a c t u a l range i n which the reagents were most e f f e c t i v e l y r e a c t i n g w i t h the p o l l u t a n t s i n the leachate. E a r l y i n the experimental programme i t was found t h a t the ozone r e q u i r e d t o o x i d i z e and consequently remove some of the m e t a l l i c p o l l u t a n t s was part o f , and intermediate t o , an i n i t i a l t o t a l r a p i d take up of the a p p l i e d ozone by the leachate. "Rapid take up" of ozone as used here r e f e r s t o the t o t a l ozone t h a t i s reacted before any of the ozone i s c a r r i e d through the leachate by the c a r r i e r gaseous oxygen. Using t h i s concept of " r a p i d take up," an attempt was made t o r e l a t e t h i s t o a measurable leachate parameter and a d i s t i n g u i s h i n g p h y s i c a l c h a r a c t e r i s t i c o f the p o l l u t i n g m e t a l l i c s . The t o t a l chemical oxygen demand (COD) of the leachate was used as the measurable base parameter f o r the l e a c h a t e , while f o r the m e t a l l i c p o l l u t a n t s , the r a t i o of the i o n i c r a d i u s t o the valence was used as the d i s t i n g u i s h i n g m e t a l l i c parameter. Use of the i o n i c r a d i u s to valence r a t i o as a measure of the o x i d i z e a b i l i t y of m e t a l l i c s has been described by Goldschmitt (12) and by McKenzie et a l . (13). The way i n which an atom or i o n w i l l r e a c t i s con d i t i o n e d , i n p a r t , by s i z e (14). By p l o t t i n g the i o n i c r adius-valence r a t i o versus the r a t i o of a p p l i e d ozone to leachate-contained COD, i t was p o s s i b l e to p r e d i c t an "ordered," ozone promoted, removal sequence f o r some of the m e t a l l i c p o l l u t a n t s , and e q u a l l y important t o p r e d i c t those 13 t h a t would not be removed by p r a c t i c a l l y s i z e d ozone a p p l i c a t i o n s . I t was found t h a t b a c t e r i a l k i l l was a l s o a f u n c t i o n of the a p p l i e d ozone-COD r a t i o and t h i s was incorporated e m p i r i c a l l y i n t o the i o n i c radius-valence r a t i o . The foregoing p l o t then estimates the amount of ozone r e q u i r e d t o o x i d i z e some of the m e t a l l i c p o l l u t a n t s and the l i v i n g organisms i n a leachate f o r which the COD i s known. I t should be noted t h a t i t was not intended i n t h i s research to "model" the ozone r e a c t i o n or d i s i n f e c t i o n process, but only to f i n d a working r e l a t i o n s h i p between a leachate parameter, the ozone dose and the leachate-contained m e t a l l i c and b i o l o g i c a l p ollutants., Ozone i s both c o r r o s i v e t o treatment p l a n t and equipment and t o x i c t o l i v i n g animals and p l a n t s . These c o r r o s i v e and t o x i c q u a l i t i e s , coupled with the cost of producing ozone, have constrained the use of ozone, both as a p o l l u t a n t removal agent and as a d i s i n f e c t a n t . I f an e f f e c t i v e , minimum, s p e c i f i c , m e t a l l i c - p o l l u t a n t removal and/or d i s i n f e c t i n g ozone dose could be f i x e d , so t h a t no nonreacted ozone i s produced, then much of the treatment p l a n t t o x i c i t y containment and c o r r o s i o n r e s i s t a n c e c o n s t r u c t i o n costs could be avoided; a l s o , those ozone production costs r e s u l t i n g from overdosing could be minimized. 14 CHAPTER 3 GENERAL REVIEW OF PHYSICAL-CHEMICAL PROCESSES 3.1 General Process Description In t r e a t i n g wastewater, any processes that do not use l i v i n g organisms to e f f e c t treatment are broadly c l a s s i f i e d as physical-chemical. Many such combinations are possible and are usually made up of several p h y s i c a l or chemical unit processes. 3.2 Physical Unit Processes Physical unit processes are those treatment processes that use some p h y s i c a l c h a r a c t e r i s t i c of the wastewater contaminant or treatment mechanism to separate the contaminant from the carrying l i q u i d . This c h a r a c t e r i s t i c may be density, weight, s i z e , colour, shape or any other p h y s i c a l form. Some processes that use ph y s i c a l c h a r a c t e r i s t i c s are: screening, mixing, f l o c c u l a t i o n , sedimentation, f l o t a t i o n , f i l t r a t i o n and induced drying (15). 3.3 Chemical Unit Processes Chemical unit processes are those processes that use chemical reactions between an added reagent and the contaminant of the wastewater to change the chemical form of the contaminant. It may be rendered harmless i n , or removed from, the carrying l i q u i d . Examples of chemical 15 unit processes are: chemical p r e c i p i t a t i o n , gas t r a n s f e r , absorption, d i s i n f e c t i o n , coagulation, oxidation or reduction (15) and adsorption (16). Most chemical unit processes require a contemporary or following p h y s i c a l unit process to complete the separation of the pollutant from the wastewater. 3.4 Advantages and Disadvantages of Physical-Chemical Processes A v i a b l e physical-chemical treatment process f o r l a n d f i l l leachate would have some inherent advantages over a b i o l o g i c a l treatment process. The most important advantages would be: 1. A quick start-up and shut-down of the process to adjust to c l i m a t i c and seasonal v a r i a b i l i t y of leachate production. 2. Physical-chemical processes are not a f f e c t e d by t o x i c substances i n the leachate. 3. Physical-chemical processes are often only nominally temperature dependent. 4. Physical-chemical treatment processes are more r e a d i l y directed to t r e a t and remove s p e c i f i c target constituents of the wastewater than are b i o l o g i c a l treatment processes. Some of the disadvantages of physical-chemical treatment, i n comparison to b i o l o g i c a l treatment, might be: 1. Physical-chemical treatment processes generally produce large quantities of sludges containing the removed pollutant plus chemicals, and these sludges are often r e f r a c t o r y i n nature, and hence not amenable to further management. 16 2. In the chemical unit portion of a physical-chemical treatment process, the chemical reagents are usually added in molecular forms. The reagent molecules disassociate into the component ions or radicals and one of these components takes part in the treatment reaction and is consequently removed. The other component remains in the treated wastewater effluent and may not be acceptable in the following use or disposal stages of the wastewater. 3. Where satisfactory pollutant residuals could be achieved with either physical-chemical or biological treatment, the physical-chemical process would probably be at a cost disadvantage. 17 CHAPTER 4 SELECTION OF REAGENT AND PROCESS CANDIDATES 4.1 D i v i s i o n of the Programme into Two Phases Because of the m u l t i p l i c i t y of ph y s i c a l and chemical process candidates a v a i l a b l e , i t was necessary to divide the experimental programme into two phases. In t h i s programme d i v i s i o n , the f i r s t phase was a screening of candidates, f o r both p h y s i c a l and chemical processes; the second phase consisted of a more rigorous i n v e s t i g a t i o n of the treatment l e v e l s attainable by the physicals-chemical candidates emerging from the previous phase. The dependence of the second phase on the r e s u l t s of the preceding screening step necessitated a preliminary analysis of the f i r s t phase r e s u l t s , and t h i s format i s adhered to i n t h i s report. 4.2 Chemical Reagents A published l i s t of chemicals (17) used f o r treatment of water and wastewater, shows 73 chemical reagents. U t i l i z i n g the r e s u l t s of some preliminary experiments and a review of the general p r a c t i c e reported i n the l i t e r a t u r e , t h i s large number of p o t e n t i a l candidates was reduced to si x : lime, alum, f e r r i c c h l o r i d e , f e r r i c s u l f a t e , powdered activated carbon and ozone. Powdered activated carbon was only used as a reagent dose mixed into the leachate being treated because experimentation with carbon i n 18 t h i s and other forms, such as a d s o r p t i v e - f i l t e r i n g of leachate, was already being c a r r i e d out at the Un i v e r s i t y of B r i t i s h Columbia ( 3 , 9 ) . Ozone was included mainly as an a l t e r n a t i v e d i s i n f e c t a n t , to replace the common d i s i n f e c t a n t c h l o r i n e ; however, i t s e f f e c t as an o v e r a l l pollutant remover was examined. Supplemental to the s i x d i r e c t - a c t i n g chemicals l i s t e d above, three high-molecular-weight synthetic polymers were tested as coagulation and s e t t l i n g enhancers i n a sixteen-experiment, s t a t i s t i c a l group. A polymer from each charge p o t e n t i a l was chosen; anionic, nonionic and c a t i o n i c , from a number supplied by manufacturers' agents. The sup p l i e r s ' d i r e c t i o n s were followed f o r preparing and using the polymers. 4.3 Physical Unit Operations Screened Four p h y s i c a l unit operations, a u x i l i a r y to the use of the chosen chemicals and polymers, were selected; these were coagulation, f l o c c u l a t i o n , sedimentation and a gas-contacting column system, to i n j e c t the ozone in t o the wastewater. Since development of the effectiveness of the chemical portion of the experimental programme depended heavily on the success of the p h y s i c a l unit process operation, several a p p l i c a t i o n variables such as contact time, mixing speed and the time allowed f o r s e t t l i n g were investigated i n the screening design. Table 4 l i s t s the chemical reagents and the p h y s i c a l parameters examined i n the screening experiments, as well as the quantities or measurements used i n applying these reagents and phy s i c a l unit processes. 1 9 T A B L E 4 T R E A T M E N T V A R I A B L E S S C R E E N E D AND A P P L I E D L E V E L S OF E A C H , C O R R E S P O N D I N G TO THE " H I G H " AND " L O W " L E V E L S I N D I C A T E D I N T H E S C R E E N I N G D E S I G N M A T R I X OF T A B L E 5 V a r i a b l e V a r i a b l e H i g h L e v e l L o w L e v e l D e s i g n a t i o n ( + ) ( - ) A L i m e 1 , 0 0 0 m g / 1 0 B L i m e 2 , 0 0 0 . m g / 1 0 C A l u m 7 5 m g / 1 0 D F e r r i c C h l o r i d e 1 6 7 m g / 1 0 . E A l u m 1 2 5 m g / 1 0 F T i m e o f F l o c c u l a t i o n 4-0 m i n 2 0 m i n G B l a n k - -H S p e e d o f F l o c c u l a t i o n 4 0 r p m 2 0 r p m I S e t t l i n g T i m e 6 0 m i n 3 0 m i n J S l u d g e R e c y c l e 1 0 , 0 0 0 m g / 1 0 K A c t i v a t e d C a r b o n 5 0 m g / 1 0 L F e r r i c S u l f a t e 2 5 0 m g / 1 0 M O z o n e 9 0 ± 3 0 m g / 1 0 N B l a n k - -0 B l a n k -20 CHAPTER 5 EXPERIMENTAL DESIGN 5.1 S t a t i s t i c a l F a c t o r i a l Design Because the purpose of t h i s i n v e s t i g a t i o n i n v o l v e d the p o s s i b l e e f f e c t s of a number of f a c t o r s , that i s , chemical reagents and the c o n t r o l of p h y s i c a l techniques i n the removal of p o l l u t a n t s from l a n d f i l l l e a c h a t e , a s t a t i s t i c a l , f a c t o r i a l l y designed s e r i e s of experiments was chosen as the most e f f i c i e n t approach. In a s t a t i s t i c a l , f a c t o r i a l l y designed experiment, the a p p l i e d v a r i a b l e s are used at two or more l e v e l s ( i n t h i s case two) and i n a l l p o s s i b l e combinations with each other at the chosen l e v e l s . By an appropriate manipulation of the obtained data, f o r a block of experiments, the e f f e c t of each v a r i a b l e i n causing a change i n the dependent parameter can be determined. In a d d i t i o n t o t h i s main e f f e c t , a measure of the i n t e r a c t i o n of the a p p l i e d v a r i a b l e s may be determined, i n a complete f a c t o r i a l design. 5.2 F r a c t i o n a l F a c t o r i a l Design A s p e c i a l case of the f a c t o r i a l l y designed experiments i s a saturated f r a c t i o n a l f a c t o r i a l design, which permits the i n v e s t i g a t i o n of up to "n - 1" a p p l i e d or independent v a r i a b l e s i n "n" experiments; however, t h i s saturated f r a c t i o n a l design does not give an estimate of the i n t e r a c t i o n s between any two a p p l i e d v a r i a b l e s . These p a r t i c u l a r designs, 21 often r e f e r r e d to as Placket-Burman (.18) designs are notably u s e f u l f o r screening applied variables (.19), that i s , i n determining which applied variables have a s i g n i f i c a n t e f f e c t , i n going from one applied l e v e l to another applied l e v e l , on a p a r t i c u l a r dependent v a r i a b l e . " S i g n i f i c a n t e f f e c t , " as used here, means an e f f e c t greater than the v a r i a t i o n s that appear i n any experimental work due to errors or manipulative causes. A saturated, f r a c t i o n a l design matrix i s shown i n Table 5 f o r "n" = 16 experiments. This i s the screening design used, and by using only 12 of the 15 possible treatment v a r i a b l e s , the data manipulations f o r the unused treatment v a r i a b l e p o s i t i o n s may be used to provide an estimate of the variance and the standard deviation. In the design matrix shown i n Table 5, the pluses (+) and minuses (-) ( i n the columns under the applied variables designations) indi c a t e the p a r t i c u l a r high and low l e v e l s r e s p e c t i v e l y , f o r the applied variables i n each of the rows of runs or i n d i v i d u a l experimental t e s t s , numbered 1 to 16 i n the left-hand column. Shown i n Table 4, i n addition to the v a r i a b l e s , are the Variable Designations and the high and low of the applied variables used i n the screening experiments. Because of the importance of lime and alum indicated i n the l i t e r a t u r e , these were included as two separate v a r i a b l e s , each with the consequent four applied l e v e l s and a l l combinations of those l e v e l s . In the screening experiments, twelve p o l l u t i n g c h a r a c t e r i s t i c s or dependent variables of the leachate were measured before and a f t e r treatment, f o r each of the sixteen experimental runs. These twelve dependent variables are l i s t e d i n Table 6, as are the concentrations or value of that dependent variable i n the p a r t i c u l a r untreated leachate. The experiments were performed i n random order and the response measured 22 TABLE 5 PACKET-BURMAN DESIGN FOR DETERMINING THE EFFECT OF 15 VARIABLES, AT TWO LEVELS EACH, USING 16 RUNS MATRIX FOR SCREENING DESIGN RUN NO. APPLIED VARIABLES A B C D E F G* H I J K L M N* 0* 1 + + + t - + - + + - - + - - -2 + + + - + - + + - - + - - - + 3 + + - + - + + - - + - - - + + 4 + - + - + + - - + - - - + + + 5 - + - + + - - + - - - + + + + 6 + + + - - + - - - + + + + -7 - + + - - + - - - + + + + - + 8 + + - - + - - - + + + + - + -9 + - - + - - - + + + + - + - + 10 - - + - - - + + + + - + - + + 11 - + - - - + + + + - + - + + -12 + - - - + + + + - + - + + - -13 - - - + + + + - + - + + - - + 14 - - + + + + - + - + + - - + -15 - + + + + - + - + + - - + - -16 + + + + - + - + + - - + - - -Note: For the purpose of the p r o j e c t , 12 variables represent r e a l changes i n the l e v e l of the v a r i a b l e s , while 3 v a r i a b l e s , marked with an ast e r i s k (.*) are dummy variables used to estimate experimental error (19). T A B L E 6 P O L L U T A N T S M E A S U R E D I N T H E S C R E E N I N G P R O C E S S P H T u r b i d i t y ( t u r b ) T o t a l C a r b o n ( T C ) T o t a l S o l i d s ( T S ) C a d m i u m ( C d ) Z i n c ( Z n ) 5 . 0 3 6 0 7 , 3 8 0 8 , 6 0 0 0 . 0 3 5 3 2 . 5 I r o n ( F e ) C a l c i u m ( C a ) P o t a s s i u m ( K ) S o d i u m ( N a ) P h o s p h o r u s ( P ) C o p p e r ( C u ) 4 4 1 5 6 0 2 7 0 3 7 0 1 5 . 1 0 0 . 0 4 3 D e p e n d e n t v a r i a b l e s ( p o l l u t a n t s ) m e a s u r e d i n t h e l e a c h a t e f o r t h e e x p e r i m e n t a l b l o c k o f 1 6 s c r e e n i n g e x p e r i m e n t s . V a l u e s s h o w n a r e i n m g / 1 e x c e p t f o r p H , w h i c h i s i n p H u n i t s , a n d t u r b i d i t y , i n H a c h f o r m a z i n t u r b i d i t y u n i t s , a n d a r e t h e v a l u e s o f e a c h v a r i a b l e i n u n t r e a t e d l e a c h a t e . 24 f o r each dependent v a r i a b l e , t h a t i s , the r e s i d u a l i n the t r e a t e d leachate was measured by appropriate l a b o r a t o r y a n a l y t i c a l techniques(20). The response measurements, f o r the screening experiments, are d i s p l a y e d i n Table 7. 5.3 C a l c u l a t i o n of E f f e c t s C a l c u l a t i n g the net average e f f e c t and i t s s t a t i s t i c a l s i g n i f i c a n c e , i n going from the low l e v e l to the high l e v e l of any of the a p p l i e d independent v a r i a b l e s , were the next two steps. For each of the designated, independent a p p l i e d v a r i a b l e s , that i s , a p p l i e d reagents or u n i t process l e v e l , the net e f f e c t i s the d i f f e r e n c e between the average of the sum of the dependent responses obtained at the high l e v e l a p p l i e d and that obtained at the low a p p l i e d l e v e l . For example, the e f f e c t of " v a r i a b l e A ( l i m e ) " on the dependent v a r i a b l e " t u r b i d i t y " i s : T,r.r. £ Responses at "( + )" Z Responses at " ( - ) " E f f e c t A = No. Responses at "(+)" No. Responses at " ( - ) " Therefore, from Tables 5 and 7, the e f f e c t of lime (A) on t u r b i d i t y i s given by: . v V 95 + 66 + 40 t 120 + 100 + 24 + 76 + 55 E f f e c t (Turb)= 78 + 104 + 60 + 93 + 45 + 72 + 106 + 60 5.25 Hach T u r b i d i t y Units, T A B L E 7 FOUND V A L U E S OF P O L L U T A N T S M E A S U R E D I N T H E S C R E E N I N G E X P E R I M E N T S D E P E N D E N T V A R I A B L E RUN N O S . P H T u r b T C T S C d Z n F e C a K N a P C u 1 8 . 0 5 9 5 6 , 4 2 0 1 2 , 2 7 9 0 . 0 2 9 1 . 0 8 • 2 7 . 9 9 0 0 2 5 7 3 6 0 0 . 6 2 5 0 . 0 4 3 2 8 . 5 0 6 6 6 , 3 7 4 1 2 , 6 4 2 0 . 0 2 9 1 . 1 7 1 3 . 5 6 2 5 2 4 0 3 3 6 2 . 9 7 5 0 . 0 4 2 3 8 . 4 5 4 0 6 , 4 8 0 1 2 , 8 7 6 0 . 0 1 8 1 . 0 7 9 . 4 7 7 5 2 4 2 3 3 0 0 . 8 2 0 . 0 3 6 4 5 . 5 5 1 2 0 6 , 4 8 0 1 0 , 5 5 9 0 . 0 4 2 3 8 . 0 1 3 7 . 5 8 8 0 2 4 9 3 5 9 1 1 . 4 4 0 . 0 5 4 5 7 . 4 0 7 8 6 , 3 6 0 1 2 , 1 4 6 0 . 0 3 0 3 . 1 3 3 7 . 5 7 0 0 2 4 8 3 9 9 1 6 . 2 0 0 . 0 4 9 6 5 . 6 0 1 0 0 5 , 9 7 5 1 0 , 4 2 8 0 . 0 6 4 3 3 . 7 5 1 7 5 . 0 5 2 5 2 4 9 3 5 8 1 0 . 8 0 0 . 0 7 0 7 6 . 7 0 1 0 4 6 , 6 2 0 1 2 , 3 2 6 0 . 0 3 5 1 6 . 5 1 0 5 . 0 7 5 0 2 5 6 3 5 1 7 . 2 8 0 . 0 7 1 8 9 . 1 1 2 4 6 , 9 3 0 1 2 , 7 9 7 0 . 0 3 1 0 , 7 2 3 . 5 7 5 2 2 4 3 3 2 6 0 . 3 7 5 0 . 0 3 0 9 5 . 0 6 7 6 6 , 5 4 0 1 0 , 9 6 5 0 . 0 3 9 3 2 . 2 5 2 5 0 5 7 5 2 5 7 3 5 0 1 1 . 7 0 0 . 0 6 5 1 0 5 . 0 9 6 0 7 , 2 0 0 8 , 7 6 9 0 . 0 4 1 4 0 . 7 5 4 4 0 5 8 0 2 7 0 3 6 5 1 6 . 2 0 0 . 0 5 1 1 1 6 . 9 3 9 3 6 , 3 3 0 1 2 , 0 3 2 0 . 0 3 7 1 4 . 5 4 3 . 7 5 9 9 0 2 2 5 2 2 0 3 . 9 0 0 . 0 5 7 1 2 5 . 5 5 5 5 6 , 5 5 0 1 0 , 7 0 1 0 . 0 4 1 3 0 . 2 5 1 5 0 5 3 7 2 4 8 3 5 3 5 . 2 5 0 . 0 4 0 1 3 5 . 0 0 4 5 6 , 7 8 5 9 , 2 5 1 0 . 0 4 2 3 3 . 7 5 4 5 7 4 9 0 2 6 7 3 6 0 1 5 . 0 0 0 . 1 3 0 1 4 5 . 0 0 7 2 7 , 1 6 0 9 , 0 0 5 0 . 0 4 8 3 2 . 5 4 7 5 3 5 0 2 6 6 3 7 0 1 6 . 2 0 0 . 0 5 7 1 5 6 . 1 6 1 0 6 6 , 7 8 0 1 1 , 7 9 3 0 . 0 3 1 2 5 . 0 1 6 . 7 0 5 6 7 5 2 4 8 3 5 1 9 . 6 0 0 . 0 4 1 1 6 5 . 0 3 6 0 7 , 3 8 0 8 , 5 9 8 0 . 0 3 5 3 2 . 5 4 4 1 5 6 0 2 7 0 3 7 0 1 5 . 1 0 0 . 0 4 3 N o t e : T h e a b o v e r e p r e s e n t t h e f o u n d v a l u e s o f d e p e n d e n t v a r i a b l e s m e a s u r e d i n t r e a t e d l e a c h a t e f o r t h e 1 6 s c r e e n i n g r u n s . A l l v a l u e s a r e i n m g / 1 e x c e p t f o r p H a n d t u r b i d i t y w h i c h a r e i n p H u n i t s a n d H a c h f o r m a z i n t u r b i d i t y u n i t s r e s p e c t i v e l y . 26 This s t a t e s t h a t i n going from the low l e v e l of "A" (lime) t o the high l e v e l o f "A" ( l i m e ) , 0 and 1,000 mg/1 r e s p e c t i v e l y , the t u r b i d i t y i s decreased 5.25 Hach u n i t s . As w i l l be shown l a t e r , t h i s change i n t u r b i d i t y i s l e s s than the estimated standard e r r o r ( d e v i a t i o n ) and t h e r e -f o r e not deemed s i g n i f i c a n t ; however, i t i l l u s t r a t e s the c a l c u l a t i o n methodology. 5.4 C a l c u l a t i o n of the Standard D e v i a t i o n The data accompanying Figure 1 (shown below the f i g u r e ) i s a six-column t a b l e and from the l e f t these columns represent: 1. The rank or order number of the c a l c u l a t e d e f f e c t 2. The symbol name of the independent v a r i a b l e 3. The absolute value of the c a l c u l a t e d e f f e c t 4. The t e c h n i c a l l y c o r r e c t e d value of Z, the area under a normal curve f o r a half-normal d i s t r i b u t i o n (21) 5. The absolute value of the e f f e c t m u l t i p l i e d by the Z v a l u e , and f i n a l l y , 6. The square of the Z values. This p r e s e n t a t i o n permits a r i t u a l i s t i c c a l c u l a t i o n of the standard e r r o r or d e v i a t i o n of the e f f e c t s from the formula (21, 22) E(Value)(Z) I t i s to be noted t h a t the standard d e v i a t i o n of the responses may be determined from the unused or dummy columns (17) where: 27 0 2 4 6 8 1 0 II 1 2 1 3 1 4 O R D E R N U M B E R S ORDER E F F E C T A B S O L U T E z ( V A L U E H Z ) ( Z ) 2 NUMBER N A M E V A L U E 1 H 0.50 0.079 0.0395 0.0062 2 D 2.00 0.158 0.3160 0.0250 3 B 2.25 0.239 0.5377 0.0571 4 N 2.50 0.322 0.8050 0.1037 5 0 3.75 0.408 1.5300 0.1665 6 K 4.25 0.496 2.1080 0.2460 7 A 5.25 0.589 3.0922 0.3469 8 I 5.50 0.688 3.7840 0.4733 9 F 6.75 0.794 5.3595 0.6304 10 E 7.75 0.910 7.0525 0.8281 11 G 8.00 1.040 8.3200 1.0816 12 L 9.00 £32.9444 Z3.9648 13 J 15.00 14 C 31.50 Z(VALUE)(Z) 15 M 33.75 s - £(Z 2) - 3 2 • 9 4 4 ~ 3.9648 = 8.31 Figure 1. Half-normal p l o t of the screening data f o r t u r b i d i t y w i t h r e l a t e d t a b u l a t e d example of the standard d e v i a t i o n c a l c u l a t i o n . 28 _ C 2 + N 2 + O 2 S 3 , (2) where C, N, and 0 are the e f f e c t s of the dummy v a r i a b l e s . The d i f f e r e n c e i n the estimate of the standard d e v i a t i o n , by the two c a l c u l a -t i o n s , i s not s u f f i c i e n t to a l t e r the end r e s u l t . 5.5 Determining the S i g n i f i c a n c e of the E f f e c t s Using the method proposed by D a n i e l (23) and modified by Zahn (21, 22) f o r determining the s i g n i f i c a n t e f f e c t s i n a s i n g l e r e p l i c a t i o n f a c t o r i a l experiment, the c a l c u l a t e d absolute values of the e f f e c t s are p l o t t e d versus the corresponding order number of the ranked e f f e c t s . The sc a l e of the v e r t i c a l a x i s , on which the e f f e c t values are p l o t t e d , i s i n m u l t i p l e s of the estimated standard d e v i a t i o n , while on the h o r i z o n t a l a x i s , the ranked order numbers are p l o t t e d at t h e i r c o r r e c t e d ( 21) half-normal p e r c e n t i l e s . Included on the p l o t t i n g g r i d are s o - c a l l e d "Guard R a i l s " (21, 23), marking o f f the 60%, 80% and 95% confidence l i m i t s used t o detect the s i g n i f i c a n c e of the l a r g e r e f f e c t s , that i s , those e f f e c t s that do not f a l l on. the normal expected p o s i t i o n s f o r n o n s i g n i f i c a n t e f f e c t s . The normally expected p o s i t i o n s of the n o n s i g n i f i c a n t e f f e c t s are i n d i c a t e d by the diagonal l i n e beginning at the o r i g i n . For the screening experiments (runs 1-16), the half-normal p l o t of the independent v a r i a b l e e f f e c t s on t u r b i d i t y are shown i n Figure 1. In Figure 1 the s i g n i f i c a n t e f f e c t s (the e f f e c t s above the 95% confidence l i m i t ) , are the ones caused by M"(ozone) and C (alum). However, both e f f e c t s M and C were c a l c u l a t e d p o s i t i v e v a l u e s , thus i n d i c a t i n g t h a t 29 ozone, and alum contribute to increasing t u r b i d i t y . The e f f e c t of J (sludge recycle) was calculated as a negative e f f e c t , thereby diminishing t u r b i d i t y , but the p r o b a b i l i t y of sludge recycle being a r e a l e f f e c t , and lowering t u r b i d i t y , i s low, somewhere i n the order of 65%, since i t f a l l s only s l i g h t l y above the 60% confidence l i m i t "Guard R a i l . " Figures 1 through 12, with the accompanying e f f e c t data and standard deviation c a l c u l a t i o n , show the p l o t t i n g f o r s i g n i f i c a n c e of the "calculated e f f e c t " data, derived from the raw data of Table 7, f o r the sixteen screening experiments. Table 8 i s a compilation of the leachate c h a r a c t e r i s t i c s which were s i g n i f i c a n t l y effected by the chemical and p h y s i c a l treatments applied. From t h i s t a b l e , i t i s noted that only lime and ozone are e f f e c t i v e i n reducing some of the monitored p o l l u t a n t s , while alum and f e r r i c s u l f a t e had a r e a l , but negative, e f f e c t on one c h a r a c t e r i s t i c each. Nevertheless, the l a t t e r two reagents were included i n the follow-up experimentation because of t h e i r common usage i n water and wastewater treatment. 3 0 ORDER NUMBERS ORDER E F F E C T A B S O L U T E z ( V A L U E H Z ) ( Z ) 2 NUMBER N A M E V A L U E 1 J 0 . 0 5 0 0 0 . 0 7 9 0 . 0 0 3 9 5 0 . 0 0 6 2 4 1 2 H 0 . 0 6 5 0 0 . 1 5 8 0 . 0 1 2 7 0 0 . 0 2 4 9 6 4 3 I 0 . 0 9 2 5 0 . 2 3 9 0 . 0 2 2 1 1 0 . 0 5 7 1 2 1 4 E 0 . 1 0 2 5 0 . 3 2 2 0 . 0 3 3 0 0 0 . 1 0 3 6 8 4 5 D 0 . 1 0 7 5 0 . 4 0 8 0 . 0 4 3 8 5 0 . 1 6 6 4 6 4 6 G 0 . 1 4 5 0 0 . 4 9 6 0 . 0 7 1 9 2 0 . 2 4 6 0 1 6 7 K 0 . 1 4 5 0 0 . 5 8 9 0 . 0 8 5 4 1 0 . 3 4 6 9 2 1 8 D 0 . 1 5 0 0 0 . 6 8 8 0 . 1 0 3 2 0 0 . 4 7 3 3 4 4 9 F 0 . 1 5 7 5 0 . 7 9 4 0 . 1 2 8 0 6 0 . 6 3 0 4 3 6 1 0 L 0 . 1 6 0 0 0 . 9 1 0 0 . 1 4 5 5 0 0 . 8 2 8 1 0 0 1 1 C 0 . 3 0 2 5 1 . 0 4 0 0 . 3 1 4 5 0 1 . 0 8 1 6 0 0 1 2 N 0 . 3 1 7 5 E 0 . 9 6 4 2 0 E 3 . 9 6 4 8 9 1 1 3 M 0 . 5 9 2 5 . 1 4 A 1 . 1 3 7 5 E ( V A L U E ) ( Z ) 1 5 B 2 . 3 6 0 0 s : E ( Z 2 ) 3 . 9 6 4 8 9 1 = 0 . 2 4 F i g u r e 2 . H a l f - n o r m a l p l o t o f t h e s c r e e n i n g d a t a f o r p H w i t h r e l a t e d t a b u l a t e d e x a m p l e o f t h e s t a n d a r d d e v i a t i o n c a l c u l a t i o n . 3 1 0 2 4 6 6 10 II 12 13 14 15 ORDER NUMBERS ORDER E F F E C T A B S O L U T E z ( V A L U E H Z ) ( Z ) 2 NUMBER N A M E V A L U E 1 C 4 3 . 3 7 5 0 . 0 7 9 3 . 4 3 0 . 0 0 6 2 4 1 2 E 5 . 9 . 3 7 5 0 . 1 5 8 9 . 3 8 0 . 0 2 4 9 6 4 3 H 6 3 . 8 7 5 0 . 2 3 9 1 5 . 2 7 0 . 0 5 7 1 2 1 4 N 6 8 . 8 7 5 0 . 3 2 2 2 2 . 1 8 0 . 1 0 3 6 8 4 5 I 7 1 . 8 7 5 0 . 4 0 8 2 9 . 3 3 0 . 1 6 6 4 6 4 6 0 8 7 . 6 2 5 0 . 4 9 6 4 3 . 4 6 0 . 2 4 6 0 1 6 7 L 8 7 . 6 2 5 0 . 5 8 9 5 1 . 6 1 0 . 3 4 6 9 2 1 8 F 9 2 . 1 2 5 0 . 6 8 8 6 3 . 3 8 0 . 4 7 3 3 4 4 9 K 1 1 8 . 6 2 5 0 . 7 9 4 9 4 . 1 9 0 . 6 3 0 4 3 6 1 0 D 1 7 0 . 1 2 5 0 . 9 1 0 1 5 4 . 8 1 0 . 8 2 8 1 0 0 1 1 G 1 7 7 . 1 2 5 1 . 0 4 0 1 8 4 . 2 1 1 . 0 8 1 6 0 0 1 2 B 2 2 1 . 8 7 5 £ 6 7 1 . 2 5 £ 3 . 9 6 4 8 9 1 1 3 J 570.625 1 4 A 3 5 9 . 8 7 5 £ ( V A L U E ) ( Z ) 1 5 M 3 8 6 . 8 7 5 s = E ( Z 2 ) _ 6 7 1 . 2 5 ~ 3 . 9 6 4 8 9 1 - 1 6 9 . 3 F i g u r e 3 . H a l f - n o r m a l p l o t o f t h e s c r e e n i n g d a t a f o r t o t a l c a r b o n w i t h r e l a t e d t a b u l a t e d e x a m p l e o f t h e s t a n d a r d d e v i a t i o n c a l c u l a t i o n . 3 2 0 2 4 6 8 10 II 12 13 14 15 ORDER NUMBERS ORDER E F F E C T A B S O L U T E z ( V A L U E H Z ) ( Z ) 2 NUMBER N A M E V A L U E 1 L 0 . 0 6 3 1 2 5 0 . 0 7 9 0 . 0 0 4 9 0 . 0 0 6 2 4 1 2 H 0 . 2 6 8 1 2 5 0 . 1 5 8 0 . 0 2 4 4 0 . 0 2 4 9 6 4 3 I 0 . 7 2 4 3 7 5 0 . 2 3 9 0 . 1 7 3 1 0 . 0 5 7 1 2 1 4 C 0 . 7 8 3 1 2 5 0 . 3 2 2 0 . 2 5 2 1 0 . 1 0 3 6 8 4 5 K 0 . 9 3 9 3 7 5 0 . 4 0 8 . 3 8 3 2 0 . 1 6 6 4 6 4 6 J 1 . 0 1 3 1 2 5 0 . 4 9 6 . 5 0 2 5 0 . 2 4 6 0 1 6 7 N 1 . 1 1 1 8 7 5 0 . 5 8 9 . 6 5 5 0 . 3 4 6 9 2 1 8 M 1 . 1 7 3 1 2 5 0 . 6 8 8 . 8 0 7 0 . 4 7 3 3 4 4 9 E 1 . 2 6 5 6 2 5 0 . 7 9 4 1 . 0 0 5 0 . 6 3 0 4 3 6 1 0 G 1 . 8 5 8 1 2 5 0 . 9 1 0 1 . 6 9 0 0 . 8 2 8 1 0 0 1 1 0 2 . 4 0 6 8 7 5 1 . 0 4 0 2 . 5 0 3 1 . 0 8 1 6 0 0 1 2 F 2 . 7 4 0 6 2 5 LB. 0 1 9 3 7 2 L3.964891 1 3 D 3 . 6 4 3 7 5 1 4 A 6 . 9 9 8 1 2 5 £ ( V A L U E ) ( Z ) 1 5 B 7 . 5 5 3 1 2 5 s E ( Z 2 ) 8 . 0 1 9 3 7 2 3 . 9 6 4 8 9 1 = 2 . 0 2 F i g u r e 4 . H a l f - n o r m a l p l o t o f t h e s c r e e n i n g d a t a f o r p h o s p h o r u s w i t h r e l a t e d t a b u l a t e d e x a m p l e o f t h e s t a n d a r d d e v i a t i o n c a l c u l a t i o n . 33 0 2 4 6 8 10 II 12 13 14 15 ORDER NUMBERS ORDER NUMBER E F F E C T N A M E A B S O L U T E V A L U E Z ( V A L U E H Z ) ( Z ) 2 1 0 0.636 0.079 0.050165 0.006241 2 K 0.665 0.158 0.09975 0.024964 3 C 0.680 0.239 0.16252 0.057121 4 J 0.711 0.322 0.228942 0.103684 5 E 0.793 0.408 0.323594 0.166464 6 I 0.839 0.496 0.416144 0.246016 7 H 0.857 0.589 0.504773 0.346921 8 N 0.874 0.688 0.601312 0.473344 9 G 0.893 0.794 0.709042 0.630436 10 D 0.917 0.910 0.83447 0.828100 11 M 0.924 1.040 0.96096 1.081600 12 F 0.982 1.191 £4 .891622 £ 3 . 9 6 4 8 9 1 13 A 2.042 1.376 14 B 3.451 1.626 E(VALUE)(Z) 15 L 4.035 2.051 S - —r Z(Z 2 ) 4.891622 3.964891 = 1.23 F i g u r e 5. H a l f - n o r m a l p l o t o f t h e s c r e e n i n g d a t a f o r t o t a l s o l i d s w i t h r e l a t e d t a b u l a t e d e x a m p l e o f t h e s t a n d a r d d e v i a t i o n c a l c u l a t i o n . 34 0 2 4 6 6 10 II 12 13 14 15 ORDER NUMBERS ORDER NUMBER E F F E C T N A M E A B S O L U T E V A L U E z ( V A L U E K Z ) ( Z ) 2 1 I 0.0000625 0 .079 0.049375 X 10 - 4 0.006241 2 H 0.0016875 0 .158 2.666 X 10 - 4 0.024964 3 A 0.0018375 0 .239 4.391625 X 10 - 4 0.057121 4 J 0.0019375 0 .322 6.23875 X 10 - 4 0.103684 5 D 0.0022125 0 .408 9.027 X 10 - 4 0.166464 6 E 0.0023125 0 .496 11.47 X 10 - 4 0.246016 7 0 0.0025875 0 .589 15.240375 X 10 - 4 0.346921 8 N 0.0025875 0 .688 17.802 X 10 - 4 0.473344 9 G 0.0027875 0 .794 22.13275 X 10 - 4 0.630436 10 F 0.0027875 0 .910 25.36625 X 10 - 4 0.828100 11 L 0.0032875 1 .040 34.19 X 10 - 4 1.081600 12 K 0.0062125 1148.57438 x 10 - 4 E3. 964891 13 C 0.0065875 14 M 0.0066625 Z(VALUE)(Z) 15 B 0.0130625 s — Ul2) 148.57438 x 10 - 4 3.964891 = 0.0037 Figure 6. Half-normal plot of the screening data for cadmium with related tabulated example of the standard deviation calculation. 35 0 2 4 6 8 10 II 12 13 14 15 ORDER NUMBERS ORDER NUMBER EFFECT NAME ABSOLUTE VALUE Z (VALUE H Z ) ( Z ) 2 1 M 0.000625 0.079 0.000049 0.006241 2 E 0.003375 0.158 0.000533 0.024964 3 C 0.005125 0.239 0.001224 0.057121 4 N 0.006375 0.322 0.002052 0.103684 5. H 0.006375 0.408 0.002601 0.166464 6 L 0.008500 0.496 0.004216 0.246016 7 G 0.009375 0.589 0.0055287 0.346921 8 F 0.009625 0.688 0.006622 0.473344 9 I 0.010375 0.794 0.00823775 0.630436 10 0 0.012125 0.910 0.0113375 0.828100 11 A 0.012325 1.040 0.012818 1.081600 12 J 0.014625 ZO.05491056 £3.964891 13 D 0.015375 14 K 0.018250 E(VALUE)(Z) 15 B 0.020125 s Z(Z 2) 0.05491056 3.964891 = 0.014 F i g u r e 7. H a l f - n o r m a l p l o t o f t h e s c r e e n i n g d a t a f o r c o p p e r w i t h r e l a t e d t a b u l a t e d e x a m p l e o f t h e s t a n d a r d d e v i a t i o n c a l c u l a t i o n . 36 ORDER NUMBERS ORDER NUMBER EFFECT NAME ABSOLUTE VALUE z (VALUE ) ( Z ) ( Z )2 1 0 0.210 0 .079 0.01659 0 006241 2 F 0.4525 0 .158 0.071495 0 024964 3 K 0.580 0 .239 0.13862 0 057121 4 D 1.2325 0 .322 0.396865 0 103684 5 E 1.2350 0 .408 , 0.50388 0 166464 6 N 1.260 0 .496 0.62496 0 246016 7 L 2.3825 0 .589 1.4032925 0 346921 8 G 2.6950 0 .688 1.85416 0 473344 9 J 2.8950 0 .794 2.29863 0 630436 10 H 3.2075 0 .910 2.918825 0 828100 11 I ' 4.6475 1 .040 4.8334 1 081600 12 C 4.803375 £15.060717 £3 964891 13 M 6.4800 14 A 7.2925 £(VALUE)(Z) 15 B 26.560375 s £(Z 2) _ 15.060719 3.964891 = 3.8 F i g u r e 8. H a l f - n o r m a l p l o t o f t h e s c r e e n i n g d a t a f o r z i n c w i t h r e l a t e d t a b u l a t e d e x a m p l e o f t h e s t a n d a r d d e v i a t i o n c a l c u l a t i o n . 37 0 2 4 6 8 10 II 12 13 14 15 ORDER NUMBERS ORDER EFFECT ABSOLUTE z ( VALUE )(Z) (Z) 2 NUMBER NAME VALUE 1 0 10.75 0.079 0.84925 0.006241 2 c 11.75 0.158 1.8565 0.024964 3 H 18.85 0.239 4.48125 0.057121 4 L 24.50 0.322 7.889 0.103684 5 G 33.75 0.408 13.770 0.166464 6 N 56.25 0.496 27.90 0.246016 7 A 59.25 0.589 34.89825 0.346921 8 K 68.75 0.688 47.30 0.473344 9 M 75.00 0.794 59.55 0.630436 10 E 80.75 0.910 73.4825 0.828100 11 J 84.50 1.040 87.880 1.081600 12 F 85.00 E359.85675 E3.964891 13 D 85.50 14 I 127.50 E(VALUE)(Z) 15 B 208.75 s - E(Z2) _ 359.85675 3.964891 = 90.76 F i g u r e 9. H a l f - n o r m a l p l o t o f t h e s c r e e n i n g d a t a f o r c a l c i u m w i t h r e l a t e d t a b u l a t e d e x a m p l e o f t h e s t a n d a r d d e v i a t i o n c a l c u l a t i o n . 38 0 2 4 6 6 10 II 12 13 14 15 ORDER NUMBERS ORDER NUMBER EFFECT NAME ABSOLUTE VALUE Z (VALUE )(Z) ( Z ) 2 1 0 0.125 0 .079 0.009875 0.006241 2 F 0.625 0 .158 0.09875 0.024964 3 E 0.625 0 .239 0.149375 0.057121 4 J 0.875 0 .322 0.28175 0.103684 5 C 1.875 0 .408 0.765 0.166464 6 L 2.625 0 .496 1.302 0.246016 7 I 2.875 0 .589 1.693375 0.346921 8 K 3.875 0 .688 2.666 0.473344 9 L 4.125 0 .794 3.27525 0.630436 10 H 4.125 0 .910 3.75373 0.828100 11 A 5.625 1 .040 - 5.8500 1.081600 12 D 6.625 119.845125 £3.964891 13 N 9.125 14 G 9.375 E(VALUE)(Z) 15 B 12.125 s — Ul2) _ 19.845125 3.964891 = 5.0 F i g u r e 10. H a l f - n o r m a l p l o t o f t h e s c r e e n i n g d a t a f o r p o t a s s i u m w i t h r e l a t e d t a b u l a t e d e x a m p l e o f t h e s t a n d a r d d e v i a t i o n c a l c u l a t i o n . 39 0 2 4 6 8 10 II 12 13 14 15 ORDER NUMBERS ORDER EFFECT ABSOLUTE z ( VALUE H Z ) ( Z ) 2 NUMBER NAME VALUE 1 A 1.41 0.079 0.11139 0.006241 2 J 4.25 0.158 0.6715 0.024964 3 0 5.25 0.239 1.25475 0.057121 4 E 6.25 0.322 2.0125 0.103684 5 F 6.50 0.408 2.6520 0.166464 6 H 9.50 0.496 4.7120 0.246016 7 I 9.50 0. 589 5.5955 0.346921 8 M 9.50 0.688 6.5360 0.473344 9 L 10.75 0.794 4.5355 0.630436 10 D 12.25 0.910 11.1475 0.828100 11 G 14.00 1.040 14.5600 1.081600 12 K 14.50 £57.7864 £3.964891 13 N 14.75 14 C 17.75 £(VALUE)(Z) 15 B 26.50 s £(Z 2) 57.7864 3.964891 = 14.57 Figure 11. Half-normal p l o t of the screening data f o r sodium with r e l a t e d tabulated example of the standard deviation c a l c u l a t i o n . 4 0 0 2 4 6 8 10 II 12 13 14 15 O R D E R N U M B E R S ORDER NUMBER EFFECT NAME ABSOLUTE VALUE z (VALUE KZ) <Z>2 1 G 1 . 8 8 7 5 0 . 0 7 9 0 . 1 4 9 1 0 0 0 6 2 4 1 2 0 3 . 3 8 7 5 0 . 1 5 8 0 . 5 3 5 2 0 0 2 4 9 6 4 3 E 5 . 4 8 7 5 0 . 2 3 9 1 . 3 1 1 5 0 0 5 7 1 2 1 4 H 8 . 1 1 2 5 0 . 3 2 2 2 . 6 1 2 2 0 1 0 3 6 8 4 5 I 1 4 . 4 8 7 5 0 . 4 0 8 5 . 9 1 0 9 0 1 6 6 4 6 4 6 K 1 4 . 7 6 2 5 0 . 4 9 6 7 . 3 2 2 2 0 2 4 6 0 1 6 7 F 1 6 . 1 3 7 5 0 . 5 8 9 9 . 5 0 5 0 0 3 4 6 9 2 1 8 C 1 7 . 8 8 7 5 0 . 6 8 8 1 2 . 3 0 6 6 0 4 7 3 3 4 4 9 L 1 8 . 4 8 7 5 0 . 7 9 4 1 4 . 6 7 9 1 0 6 3 0 4 3 6 1 0 D 3 2 . 3 6 2 5 0 . 9 1 0 2 9 . 4 4 9 9 0 8 2 8 1 0 0 1 1 J 3 4 . 2 3 7 5 1 . 0 4 0 3 5 . 6 0 7 0 1 0 8 1 6 0 0 1 2 N 6 1 . 8 6 2 0 1 1 1 9 . 3 8 8 7 9 6 4 8 9 1 1 3 M 9 9 . 3 6 2 5 1 4 A 1 7 5 . 7 6 2 5 £ ( V A L U E ) ( Z ) 1 5 B 2 6 5 . 3 6 2 5 s - £ ( Z 2 ) 3 . 9 6 4 8 9 1 = 3 0 . 1 F i g u r e 1 2 . H a l f - n o r m a l p l o t o f t h e s c r e e n i n g d a t a f o r i r o n w i t h r e l a t e d t a b u l a t e d e x a m p l e o f t h e s t a n d a r d d e v i a t i o n c a l c u l a t i o n . 4 1 T A B L E 8 C O M P I L A T I O N OF S T A T I S T I C A L L Y S I G N I F I C A N T E F F E C T S FOR I N D E P E N D E N T V A R I A B L E S I N T H E S C R E E N I N G E X P E R I M E N T S E X P E R I M E N T D E S C R I P T I O N L E A C H A T E C H A R A C T E R I S T I C S I G N I F I C A N T L Y A F F E C T E D B Y C H A N G E I N L E V E L S OF T R E A T M E N T V A R I A B L E S S t a t i s t i c a l G r o u p 1 R u n s # 1 - 1 6 ( S c r e e n i n g ) T r e a t m e n t V a r i a b l e s V a r i a b l e H i g h " L o w * L e v e l L e v e l L i m e 1 0 0 0 0 p H , P , F e L i m e 2 0 0 0 0 p H , P , C d , Z n , F e A l u m 2 0 0 t 0 T u r b . * * F e r r i c C h l o r i d e 1 6 7 0 F e r r i c S u l f a t e 2 0 0 0 T S * * A c t i v a t e d C a r b o n 5 0 0 S l u d g e R e c y c l e 5 0 0 T u r b . O z o n e 5 0 ± 1 0 0 p H * * * , pA** 9 T u r b . * * , F e * * * T i m e f o r F l o c c u l a t i o n 4 0 M i n 2 0 M i n S e t t l i n g T i m e 6 0 M i n 3 0 M i n S p e e d f o r F l o c c u l a t i o n 4 0 R P M 2 5 R P M * M g / 1 u n l e s s o t h e r w i s e s h o w n . "f* T h i s i s v a l u e f o r c o m b i n e d h i g h l e v e l s . * * S i g n i f i c a n t l y i n c r e a s e d t h i s c h a r a c t e r i s t i c i n e f f l u e n t . * * * O f l o w s i g n i f i c a n c e . 4-2 CHAPTER 6 EXPERIMENTAL APPARATUS AND ANALYTICAL METHODS The components of the apparatus assembled to conduct the experimental programme consisted of two main u n i t s , the "ozone generation and contacting" system assembly, and the "physical unit processes simulation" system assembly. 6.1 Ozone Generating and Contacting System A schematic flow diagram of the ozone generation and contacting system i s shown i n Figure 13. For ozone generation, a Grace Laboratory Generator was used. This type of ozone generator produces ozone, from the oxygen i n a i r or from pure oxygen, by passing these gases between electrodes with an a l t e r n a t i n g high-voltage d i f f e r e n c e . A uniform glow discharge, commonly c a l l e d a s i l e n t discharge, i s maintained i n the gas by i n s e r t i n g a d i e l e c t r i c between the electrodes. Only oxygen was used i n t h i s study; t h i s was zero grade (hydro-carbons le s s than 5 ppm) commercial oxygen supplied from a pressure c y l i n d e r . The flow rate of the ozone-oxygen mixture stream from the ozone, generator was c o n t r o l l e d and proportioned into two p a r t s , by a set of three rotameters. One part went d i r e c t l y i n t o a.potassium-iodide trap f o r the analysis of the ozone content, followed by volume measurement v i a a wet-test volume meter. The second part was introduced into a 1.37 meter high by 9.5 centimeter inside diameter polished l u c i t e c y l i n d e r , containing —r> OXYGEN CONTACT CYLINDER OZONE OZONE GENERATOR WET TEST K.I.TRAP .METER DETERMINATION OF O Z O N E IN O Z O N E -O X Y G E N S T R E A M WET TEST METER DETERMINATION OF O Z O N E IN O F F -O X Y G E N S T R E A M 0 Control Valves LEACHATE RECYCLE PUMP FIG.I3'SCHEMATIC OF OZONATING SYSTEM CO 44 the sample of leachate t o be ozonated. The ozone-oxygen stream was dispersed i n t o the leachate through a f i n e - p o r o s i t y f r i t t e d gas d i s p e r s i o n tube, mounted near the bottom of the l u c i t e contact c y l i n d e r . The leachate i n the c y l i n d e r was r e c y c l e d at a constant r a t e of 1.5 l i t e r s per minute, counter-current to the gas f l o w ; t h i s was performed mainly t o provide a foam d i s p e r s i o n spray on the top surface of the leachate i n the c y l i n d e r . The gas stream e x i t i n g the contact c y l i n d e r was l e d t o a second potassium i o d i d e t rap and then t o a wet-test volume meter assembly, to measure the ozone content and volume of the e x i t i n g gas. I t should be noted t h a t a l l experiments were conducted w i t h no ozone escaping the contact chamber, i n d i c a t i n g t h a t a l l of the ozone being a p p l i e d reacted i n the leachate. The foregoing was excepted i n one run t h a t was c a r r i e d through t o the p o i n t where a breakthrough, of unreacted ozone, was noted; t h i s breakthrough caused a d i s c o l o u r a t i o n of the contents of the potassium i o d i d e t r a p . 6.2 P h y s i c a l Unit Processes S i m u l a t i o n The p h y s i c a l u n i t processes s i m u l a t i o n was made using two standard, six-paddle l a b o r a t o r y s t i r r i n g d e v i c e s , commonly c a l l e d " j a r t e s t apparatus." The apparatus allows r a p i d mixing during and a f t e r the a d d i t i o n of reagents and then the s t i r r i n g paddles may be slowed t o any chosen speed, thus p e r m i t t i n g the coagulation and f l o c c u l a t i o n of the p r e c i p i t a t e or f l o e formed. The s p e c i f i c apparatus used was manufactured by Phipps and B i r d . 45 6.3 A n a l y t i c a l Methods Measurement of the c h a r a c t e r i s t i c s of the raw leachate, used i n t h i s i n v e s t i g a t i o n , was made by the s t a f f of the Environmental Engineering Laboratory, Department of C i v i l Engineering, University of B r i t i s h Columbia. These measurements were i n accordance with procedures of Standard Methods (20), with minor modifications as noted i n the reference by McDonald and Cameron (24). B a c t e r i a l counts on ozonated leachate were determined using procedures that are described i n the following Section 6.5. The " a f t e r treatment" c h a r a c t e r i s t i c s were measured using the same procedures as f o r the raw leachate and these procedures are b r i e f l y described i n the following: pH - A l l determinations were made with a Fisher accumet pH Meter, Model 210. Turbidity - The t u r b i d i t y was measured with a nepholmeter procedure (20), using a Hach Turbidimeter, Model 2100A. Colour - The colour was determined using a Helige Aqua Tester i n accordance with the manufacturer's s p e c i f i c a t i o n s . Solids - Solids determinations were made using methods described i n Standard Methods (20). M e t a l l i c Ions - The m e t a l l i c - i o n species Cd, Ca, K, Na, Cu, Mn and Zn were determined on a Jarrel-Ash Model 82-516, Atomic Adsorption Spectrophotometer. The method employed 46 To t a l Carbon and Inorganic Carbon Chemical Oxygen Demand Ozone d i r e c t a s p i r a t i o n with both concentrated and nonconcentrated samples of leachate, as appropriate, f o r the quantity of contained m e t a l l i c ion. The carbons were analyzed by the procedures of Standard Methods (20), using a Beckman Model 915, coupled total-carbon and inorganic carbon analyzer. COD was determined by the "Dichromate Method" of Standard Methods (20). Ozone was determined by the "Idiometric" procedure, as outlined i n Standard Methods (20). 6.4 D i s i n f e c t i o n with Ozone The l i t e r a t u r e contains numerous references and information e s t a b l i s h i n g the effectiveness of ozone as a v i r a l and b a c t e r i a l d i s i n f e c t a n t . Bringman (25) states that, i n t e s t s c a r r i e d out, ozone was 600 to 3,000 times more rapid than chlorine i n b a c t e r i a l d i s i n f e c t i o n . Ingols and Fetner (26) conclude that b a c t e r i a l k i l l by chlorine i s progressive, as compared to ozone which i s sudden and.'total,rafter a "threshold" dose has been applied. Because of t h i s established d i s i n f e c t i o n a b i l i t y of ozone, only a l i m i t e d confirmatory evaluation of the d i s i n f e c t i o n by ozone was planned into t h i s experimental pr o j e c t ; the main emphasis was on determining the dose at which b a c t e r i a l k i l l was accomplished. 1+7 6.5 Ozone D i s i n f e c t i o n Procedure Standard P l a t e Counts at 35°C u s i n g P l a t e Count Agar (Tryptone Glucose Yeast Agar) (20) were made on a s e r i e s of no n d i l u t e d samples of ozonated leachate. Each s e q u e n t i a l sample, numbered from 1 t o 9, had an i n c r e a s i n g ozone dose ranging from 0 mg/1 t o 163 mg/1. Fol l o w i n g t h i s s e q u e n t i a l l y i n c r e a s i n g ozone dose t e s t , 9 Standard P l a t e Counts at 35°C were made, using leachate samples ozonated with a common ozone dose of 110 mg/1 each; 5 of these samples were u n d i l u t e d and 4 were d i l u t e d 1-10, with Stock B u f f e r S o l u t i o n (20). A l l p l a t e counts were made using a Quebec colony counter. Recording of P l a t e Counts were i n accordance t o the procedures of Standard Methods (20). 48 CHAPTER 7 PRESENTATION AND DISCUSSION OF DATA 7.1 Data—Screening Experiments Table 4 shows the applied dose l e v e l s of the reagents screened, as well as the parameters of the p h y s i c a l unit operations screened. Table 6 l i s t s the dependent variables (pollutants) measured i n the treated leachate, and also shows the o r i g i n a l concentration of the monitored pollutants i n the untreated leachate. Table 7 gives the r e s i d u a l concentration of each of the monitored pollutants i n the treated leachate from the screening experiments. 7.2 Discussion of Screening Data The d e t a i l e d method of manipulating the raw data i s presented i n Chapter 5 of t h i s paper. The calculated independent e f f e c t data, accompanying Figures 1 through 12, i s plotted i n the figures to determine those e f f e c t s that are s t a t i s t i c a l l y s i g n i f i c a n t . Because the low l e v e l of the applied reagent doses was a zero dose, the calculated e f f e c t , caused by applying the reagent at the high l e v e l , i s a close approximation of the r e a l removal caused by the named reagent at the high l e v e l applied. This approximate r e a l e f f e c t of the p a r t i c u l a r dose i s noticeable even when a reagent i s applied as two separate doses. This separation of dose e f f e c t may be noted, i n the screening experiments, i n the a p p l i c a t i o n of lime. In Figure 2, where the dependent va r i a b l e i s pH, the calculated e f f e c t of increasing the lime dose 49 from 0 mg/1, low-level dose, to 1000 mg/1, h i g h - l e v e l dose, i s to r a i s e the pH by 1.1375 pH u n i t s , while the calculated e f f e c t of increasing the lime dose from 0 mg/1 to 2000 mg/1 i s 2.360 pH u n i t s . This a b i l i t y of the s t a t i s t i c a l l y designed experiment to estimate the e f f e c t of a p a r t i c u l a r reagent or reagent dose i s a u s e f u l datum. An example of one of these u s e f u l data observations i s i l l u s t r a t e d i n Figure 6, where i t i s shown that the dependent v a r i a b l e Cadmium i s not s i g n i f i c a n t l y removed using a 1000 mg/1 lime dose but i s s i g n i f i c a n t l y removed by a lime dose of 2000 mg/1. The r e s u l t s , derived from the p l o t s i n Figures 1 to 12, are tabulated i n Table 8 and can be summarized for each of the applied independent variables as follows: Lime. Lime was shown to have a s i g n i f i c a n t p o t e n t i a l f o r decreasing the concentration of three of the monitored p o l l u t a n t s , P, Zn, and Fe, while the increase i n t o t a l s o l i d s , a t t r i b u t a b l e to lime, approached a s i g n i f i c a n t l e v e l . Lime effected a change i n pH, r a i s i n g the pH from the o r i g i n a l value of 5.03 up to 9.11, depending on the quantity applied and the i n t e r a c t i n g e f f e c t of other reagents used at the same time. Ozone. Ozone was shown to e f f e c t a reduction i n pH and Fe. T u r b i d i t y was shown to increase from the ozone a p p l i c a t i o n . The confidence estimate f o r the reduction i n pH by ozone was approximately 90 percent. The found reduction i n pH differs'-from the findings of other investigators (27), who found that i n ozonating wastewaters, the wastewater pH c o n s i s t e n t l y changes towards n e u t r a l i t y , pH 7, during the ozone treatment. In t h i s set of experiments, the wastewater was ozonated at an o r i g i n a l pH of 5.03. To be consistent with the previously reported work, the pH should 50 have been increased towards pH 7 by the ozone treatment• The following lime addition increased the pH to well above pH 7 but the c a l c u l a t e d e f f e c t f or ozone shows a net pH reduction. No explanation f o r t h i s anomaly can be made at t h i s time. Alum. Alum had one s i g n i f i c a n t e f f e c t , namely to increase the t u r b i d i t y of the leachate. F e r r i c Sulfate. F e r r i c s u l f a t e increased the t o t a l s o l i d s content of the treated leachate, when compared to leachate treated without using f e r r i c s u l f a t e . Sludge Recycle. Slude recycle was possibly e f f e c t i v e i n reducing t u r b i d i t y but the p r o b a b i l i t y f o r t h i s was low, about 60 percent, as demonstrated i n the Figure 1 p l o t . None of the other applied v a r i a b l e s , reagents or p h y s i c a l unit processes were found to e f f e c t a s i g n i f i c a n t change i n the quantity or q u a l i t y of any of the leachate c h a r a c t e r i s t i c s measured. Lime and ozone became the prime reagent candidates f o r the follow-up research, from the r e s u l t s of the screening experiments. Alum and f e r r i c s u l f a t e were included i n the follow-up work because of the near un i v e r s a l acceptance of these reagents as useful water and wastewater treatment chemicals. The low s i g n i f i c a n c e of the s i n g l e , sludge-recycle e f f e c t precluded sludge recycle as a useful treatment v a r i a b l e . 7.3 Post-Screening Experimental Data Tables 9 to 13 display the doses of applied reagents and the order of reagent a p p l i c a t i o n f o r the 11 groups of experiments (group numbers 2 to 12) i n the post-screening experimentation. For continuity, 51 the information f o r the "screening experiments" i s included i n these tables as group number 1. The leachate c h a r a c t e r i s t i c s affected by increasing any s p e c i f i c reagent used from a low-level dose to a h i g h e r - l e v e l dose are also shown in these tables. Table 14- l i s t s the name code f o r each of the independent variables (reagents) used i n the follow-up experimentation. Tables 15 to 24 show the o r i g i n a l concentration, the high, low and mean of the r e s i d u a l concentrations, the standard deviation of the resid u a l s and the percent of the o r i g i n a l concentrations that were removed i n the best removal (lowest r e s i d u a l ) during the treatment f o r each of the 19 c h a r a c t e r i s t i c s that were monitored. Table 26 shows the best (lowest) values f o r the selected pollutants i n the treated leachate with the treatment reagents and the e f f e c t i v e reagent'dose or dose range indicated. Tables to , i n the appendix to t h i s report, are compilations of the r e s i d u a l measured concentrations of the monitored leachate p o l l u t i n g c h a r a c t e r i s t i c s , f o r a l l of the post-screening experimental runs, and i s the raw data from which the previous tables were developed. The found values f o r the post-screening experiments were s t a t i s t i c a l l y and numerically manipulated, with variants to s u i t the number of applied reagents and the data a v a i l a b l e , i n the same manner as d e t a i l e d i n Chapter 5 f o r the screening experiments. For example, f o r the experimental groups numbers 2, 4 and 10, the experimental design used was one i n which 4 independent variables (reagents) were tested i n a l l possible combinations of two l e v e l s of a p p l i c a t i o n i n 16 runs or separate experiments. Table 25 i s an i l l u s t r a t i o n of the computational matrix used 5 2 T A B L E 9 C O M P I L A T I O N OF R E A G E N T D O S I N G L E V E L S F O R GROUPS 1 , 2 , AND 3 W I T H S I G N I F I C A N T P O L L U T I N G C H A R A C T E R I S T I C SHOWN WHERE A P P L I C A B L E E X P E R I M E N T D E F I N I T I O N L E A C H A T E C H A R A C T E R I S T I C E F F E C T E D S t a t i s t i c a l G r o u p 1 R u n s # 1 - 1 6 ( O z o n a t i o n F i r s t ) T r e a t m e n t V a r i a b l e s L i m e 0 m g / 1 - 1 0 0 0 m g / 1 0 m g / 1 - 2 0 0 0 m g / 1 . A l u m 0 m g / 1 2 0 0 m g / 1 p H , P , Z n , C d , F e T u r b i d i t y * F e 2 ( S 0 4 ) 3 0 m g / 1 - 2 0 0 m g / 1 T S * O z o n e 0 m g / 1 - 5 0 m g / 1 p H * * , T u r b i d i t y * " , F e * * S l u d g e R e c y c l e 0 m g / 1 - 5 0 m g / 1 T u r b i d i t y * * S t a t i s t i c a l G r o u p 2 R u n s # 1 7 - 3 2 ( O z o n a t i o n F i r s t ) L i m e 1 2 0 0 m g / 1 - 2 0 0 0 m g / 1 p H , T u r b i d i t y * * , S S * , * * , M n , Z n A l u m 2 5 m g / 1 - 1 2 5 m g / 1 F e 2 ( S 0 4 ) 3 2 5 m g / 1 - 1 2 5 m g / 1 O z o n e 2 5 m g / 1 - 1 0 7 m g / 1 R u n s 1 9 , 2 1 , 2 4 , 2 5 , 2 6 , 2 8 o f t h i s g r o u p n o t c o m p l e t e d d u e t o l o s s o f t r e a t e d l e a c h a t e s a m p l e S t a t i s t i c a l G r o u p 3 R u n s # 3 3 - 3 6 F o u r r e p l i c a t e r u n s n o t c o m p l e t e d a s i n G r o u p 2 * I n d i c a t e s e f f e c t w a s a n i n c r e a s e * * I n d i c a t e s e f f e c t w a s o f l o w s t a t i s t i c a l s i g n i f i c a n c e 5 3 T A B L E 1 0 C O M P I L A T I O N OF R E A G E N T D O S I N G L E V E L S F O R GROUPS 4 , 5 AND 6 W I T H S I G N I F I C A N T P O L L U T I N G C H A R A C T E R I S T I C C H A N G E S SHOWN WHERE A P P L I C A B L E E X P E R I M E N T D E F I N I T I O N L E A C H A T E C H A R A C T E R I S T I C A F F E C T E D S t a t i s t i c a l G r o u p 4 R u n s # 3 7 - 5 2 ( O z o n a t i o n F i r s t ) T r e a t m e n t V a r i a b l e s L i m e A l u m 1 2 0 0 m g / 1 - 2 0 0 0 m g / 1 3 0 m g / 1 - 1 5 0 m g / 1 T C * , T S * , T O C * , C o l o u r , S S , F e , Mn p H * , D S , Z n T C F e 2 ( S 0 4 ) 3 3 0 m g / 1 - 1 5 0 m g / 1 O z o n e 5 1 m g / 1 - 9 8 m g / 1 T C , T S , T O C , C o l o u r , S S , C O D , M n , T u r b i d i t y , p H , D S , C u S t a t i s t i c a l ( 1 ) G r o u p 5K J R u n s # 5 3 - 5 6 ^ ( O z o n a t i o n F i r s t ) L i m e A l u m 1 6 0 0 m g / 1 - 2 0 0 0 m g / l ( 2 ) 9 0 m g / 1 p H , T u r b i d i t y , C o l o u r , T C * , T S * , S S , P b * , Z n , F e , C a * , Mn F e 2 ( S 0 4 ) 3 9 0 m g / 1 O z o n e 4 3 m g / 1 S t a t i s t i c a l G r o u p 6 R u n s # 5 7 - 6 1 ( O z o n a t i o n F i r s t ) L i m e 2 4 6 0 , 2 6 3 0 , 2 7 9 0 , 2 8 7 0 a n d 3 1 4 0 m g / 1 ( 3 ) A l u m 7 1 m g / 1 F e 2 ( S O l | ) 3 1 6 9 m g / 1 O z o n e 1 0 4 , 1 1 1 , 1 1 5 , 1 1 9 , 1 2 6 ( 3 ) * I n d i c a t e s e f f e c t w a s a n i n c r e a s e . N o t e ( 1 ) R u n s 5 3 - 5 5 w e r e r e p l i c a t e r u n s w i t h t h e l i m e d o s e a t 1 6 0 0 m g / 1 . N o t e ( 2 ) R u n 5 6 h a d l i m e d o s e a t 2 0 0 0 m g / 1 w i t h t h e o t h e r a p p l i e d v a r i a b l e c o n s t a n t w i t h r u n s 5 3 - 5 5 . N o t e ( 3 ) L i m e a n d o z o n e d o s e s i n c r e a s e d i n e a c h r e s p e c t i v e r u n . 5 4 T A B L E 1 1 C O M P I L A T I O N OF R E A G E N T D O S I N G L E V E L S FOR G R O U P S 7 , 8 AND 9 W I T H S I G N I F I C A N T P O L L U T I N G C H A R A C T E R I S T I C C H A N G E S SHOWN WHERE A P P L I C A B L E E X P E R I M E N T D E F I N I T I O N L E A C H A T E C H A R A C T E R I S T I C E F F E C T E D S t a t i s t i c a l G r o u p 7 R u n s # 5 7 , 6 2 , 6 3 , 6 4 ( O z o n e F i r s t ) T r e a t m e n t V a r i a b l e s L i m e 2 4 6 0 m g / 1 ( c o n s t a n t ) A l u m 0 m g / 1 - 7 5 m g / 1 F e 2 ( S 0 4 ) 3 0 m g / 1 - 1 5 0 m g / 1 O z o n e 1 0 4 m g / 1 ( c o n s t a n t ) S t a t i s t i c a l G r o u p 8 R u n s # 6 5 - 7 2 ( O z o n a t i o n F i r s t ) L i m e 2 1 0 0 m g / 1 - 2 9 0 0 m g / 1 A l u m 5 0 m g / 1 - 1 0 0 m g / 1 O z o n e 1 0 8 m g / 1 - 1 3 0 m g / 1 S t a t i s t i c a l G r o u p 9 S S , COD C o l o u r , K * , C O D * R u n s # 7 3 - 8 0 ( 1 6 0 0 m g / 1 l i m e a d d e d b e f o r e o z o n a t i o n ) L i m e 2 5 0 m g / 1 - 7 5 0 m g / 1 A l u m 2 5 m g / 1 - 7 5 m g / 1 O z o n e 1 1 m g / 1 - 1 2 7 m g / 1 C a * T I C * * I n d i c a t e s e f f e c t w a s a n i n c r e a s e . 5 5 T A B L E 1 2 C O M P I L A T I O N OF R E A G E N T D O S I N G L E V E L S FOR GROUPS 1 0 AND 1 1 W I T H S I G N I F I C A N T P O L L U T I N G C H A R A C T E R I S T I C C H A N G E S SHOWN WHERE A P P L I C A B L E E X P E R I M E N T A L D E F I N I T I O N L E A C H A T E C H A R A C T E R I S T I C E F F E C T E D S t a t i s t i c a l G r o u p 1 0 R u n s # 8 1 - 9 6 ( 1 6 0 0 m g / 1 l i m e a d d e d b e f o r e o z o n a t i o n ) L i m e 7 5 0 m g / 1 ( c o n s t a n t ) A l u m 7 5 m g / 1 ( c o n s t a n t ) O z o n e 9 7 m g / 1 - 2 4 8 m g / 1 C o l o u r , T S , M n * * A n i o n i c P o l y m e r 0 m g / 1 - 2 m g / 1 F e * * C a t i o n i c P o l y m e r 0 m g / 1 - 2 m g / 1 N o n i o n i c P o l y m e r 0 m g / 1 - 2 m g / 1 S t a t i s t i c a l G r o u p 1 1 R u n s # 9 7 - 1 0 0 ^ ( 1 6 0 0 m g / 1 l i m e a d d e d b e f o r e o z o n a t i o n ) L i m e 7 5 0 m g / 1 ( c o n s t a n t ) A l u m 7 5 m g / 1 ( c o n s t a n t ) O z o n e 1 5 9 m g / 1 ( c o n s t a n t ) A n i o n i c P o l y m e r 1 m g / 1 ( c o n s t a n t ) C a t i o n i c P o l y m e r 1 m g / 1 ( c o n s t a n t ) N o n i o n i c P o l y m e r 1 m g / 1 ( c o n s t a n t ) N o t e ( 1 ) R u n s 9 7 - 1 0 0 w e r e r e p l i c a t e r u n s m a d e t o e s t a b l i s h t h e s t a n d a r d d e v i a t i o n . * * L o w s i g n i f i c a n c e . 5 6 T A B L E 1 3 C O M P I L A T I O N OF R E A G E N T D O S I N G L E V E L S FOR GROUP 1 2 , RUNS 1 0 1 - 1 0 4 E X P E R I M E N T D E F I N I T I O N L E A C H A T E C H A R A C T E R I S T I C CHANGED S t a t i s t i c a l G r o u p 1 2 R u n s # 1 0 1 - 1 0 4 ( 1 6 0 0 m g / 1 a d d e d b e f o r e o z o n a t i o n ) L i m e 7 5 0 m g / 1 ( c o n s t a n t ) A l u m 7 5 m g / 1 ( c o n s t a n t ) O z o n e 0 , 1 2 4 , 1 8 1 , 1 8 1 m g / 1 r e s p e c t i v e l y f o r r u n s 1 0 1 - 1 0 4 A n i o n i c P o l y m e r 0 m g / 1 - 0 . 5 m g / 1 C a t i o n i c P o l y m e r 0 m g / 1 - 0 . 5 m g / 1 N o n i o n i c P o l y m e r 0 m g / 1 - 0 . 5 m g / 1 T A B L E 1 4 NAME CODES FOR T H E I N D E P E N D E N T V A R I A B L E S THE P O S T - S C R E E N I N G E X P E R I M E N T S ( G R O U P S 2 t o 1 2 ) NAME CODE I N D E P E N D E N T V A R I A B L E A L i m e B A l u m C F e r r i c S u l f a t e D O z o n e E A n i o n i c P o l y m e r F C a t i o n i c P o l y m e r G N o n i o n i c P o l y m e r 5 8 T A B L E 1 5 R E M O V A L OF S E L E C T E D P O L L U T A N T S FROM L A N D F I L L L E A C H A T E I N E X P E R I M E N T A L GROUP 2 , RUNS 1 7 , 1 8 , 2 0 , 2 3 , 2 7 , 2 9 , 3 0 , 3 1 , 3 2 O r i g i n a l V a l u e P o l l u t a n t or C o n c e n t r a t i o n i n m g / 1 R a n g e R e s i d u a l a n d M e a n o f C o n c e n t r a t i o n s i n m g / 1 S t a n d a r d D e v i a t i o n " s " P e r c e n t R e m o v e d ( b e s t ) H i g h L o w M e a n p H 5 . 2 8 5 . 9 9 6 . 9 5 6 . 6 7 0 . 0 1 5 T u r b i d i t y 5 3 2 3 0 4 9 8 7 5 9 2 C o l o u r 2 5 0 0 2 5 0 0 5 0 0 1 2 0 0 2 8 9 8 0 T o t a l C a r b o n 5 2 3 0 4 4 0 0 3 2 2 0 3 9 9 8 3 1 3 8 T o t a l I n o r g a n i c C a r b o n 3 6 . 6 4 0 . 0 4 . 0 1 5 . 8 0 . 3 2 8 9 T o t a l O r g a n i c C a r b o n 5 1 9 3 4 2 8 5 3 2 1 5 3 9 8 3 3 1 3 8 COD 1 4 1 0 5 1 2 7 1 8 9 7 3 4 1 1 5 0 7 7 0 6 3 1 C a 4 8 2 2 1 4 0 7 8 0 1 1 6 3 7 8 5 - 6 1 C u 0 . 0 3 9 0 . 1 0 6 0 . 0 3 0 0 . 0 6 4 0 . 0 0 6 2 3 F e 6 6 5 3 2 5 1 . 0 8 6 7 . 6 9 9 . 8 K 1 5 6 1 6 0 1 3 4 1 5 0 3 . 4 6 1 4 Mn 1 0 . 1 8 . 2 4 . 6 6 . 8 2 0 . 0 9 5 5 4 N a 1 8 6 1 8 5 1 5 2 1 5 7 1 0 . 7 18 P 1 1 . 5 0 . 1 9 0 0 . 1 1 0 0 . 1 4 9 0 . 0 2 6 9 9 P b 0 . 0 3 5 0 . 2 1 3 0 . 1 6 4 0 . 1 8 1 0 . 0 6 3 - 3 6 8 Z n 1 2 . 4 5 6 . 3 5 0 . 2 7 2 . 7 1 0 . 2 0 9 8 T S 6 7 7 5 9 1 3 5 7 5 3 5 8 3 6 6 6 2 - 1 1 S S 9 2 4 1 8 3 1 4 1 1 8 0 . 4 9 8 . 5 DS 5 8 5 1 9 1 0 7 7 2 6 6 8 2 4 8 6 3 - 2 4 59 T A B L E 1 6 R E M O V A L OF S E L E C T E D P O L L U T A N T S FROM L A N D F I L L L E A C H A T E I N E X P E R I M E N T A L GROUP 4 , RUNS 3 7 - 5 2 P o l l u t a n t O r i g i n a l V a l u e o r C o n c e n t r a t i o n i n m g / 1 R a n g e R e s i d u a l a n d M e a n o f C o n c e n t r a t i o n s i n m g / 1 S t a n d a r d D e v i a t i o n " s " P e r c e n t R e m o v e d ( b e s t ) H i g h L o w M e a n p H 5 . 2 8 8 . 6 0 6 . 0 5 6 . 8 5 0 . 0 1 5 T u r b i d i t y 1 0 0 2 5 5 2 5 1 4 5 1 2 7 5 C o l o u r 2 5 0 0 5 0 0 0 2 5 0 1 9 2 0 2 8 9 9 0 T o t a l C a r b o n 4 0 9 5 * 4 5 1 0 3 7 0 0 4 1 4 3 3 1 9 . 6 T o t a l I n o r g a n i c C a r b o n 2 9 . 5 * 2 9 . 2 3 . 0 1 3 0 . 3 2 9 0 T o t a l O r g a n i c C a r b o n 4 0 6 5 * 4 4 9 6 3 6 9 4 4 1 3 1 3 1 9 . 1 COD 1 3 4 8 0 * 1 4 4 0 3 9 7 0 6 1 2 5 1 8 7 0 6 2 8 C a 4 7 5 * 1 8 7 0 5 7 0 1 0 7 7 7 8 5 - 2 0 C u 0 . 0 6 0 . 1 1 0 . 0 4 1 0 . 0 6 5 0 . 0 0 6 3 2 F e 6 2 8 * 2 5 0 0 . 6 6 7 9 . 3 7 . 6 9 9 . 9 K 1 5 2 * 1 4 8 1 1 4 1 3 9 3 . 4 6 2 5 Mn 9 . 7 9 * 8 . 2 1 . 5 6 . 1 2 0 . 0 9 5 8 5 N a 1 6 0 * 2 5 5 1 2 8 1 5 9 1 0 . 7 2 0 P 1 0 . 1 * 0 . 4 1 0 . 0 7 0 . 1 3 0 . 0 2 6 9 9 . 3 P b 0 . 0 3 3 * 0 . 2 0 3 0 . 0 5 7 0 . 1 3 0 . 0 6 3 - 7 3 Z n 1 1 . 8 4 . 8 3 0 . 0 4 1 . 8 8 0 . 2 0 9 9 . 7 T S 6 6 0 2 * 8 9 4 5 7 0 0 6 8 3 5 5 6 2 - 3 . 7 S S 8 2 3 * 1 0 6 1 1 4 2 8 6 0 . 4 9 8 . 3 DS 5 7 9 9 * 9 1 1 1 6 9 4 9 8 0 7 4 6 3 - 2 0 * A v e r a g e o f t w o e i g h t - l i t r e l o t s . 6 0 T A B L E 1 7 R E M O V A L OF S E L E C T E D P O L L U T A N T S FROM L A N D F I L L L E A C H A T E I N E X P E R I M E N T A L GROUP 5 , RUNS 5 3 - 5 6 P o l l u t a n t O r i g i n a l V a l u e o r C o n c e n t r a t i o n i n m g / 1 R a n g e R e s i d u a l a n d M e a n o f C o n c e n t r a t i o n s S t a n d a r d D e v i a t i o n " s " P e r c e n t R e m o v e d ( b e s t ) H i g h L o w M e a n p H 5 . 2 8 8 . 2 0 6 . 8 0 7 . 1 6 0 . 0 1 5 T u r b i d i t y - 1 0 0 2 0 0 5 0 1 5 3 7 5 5 0 C o l o u r 2 5 0 0 1 5 0 0 5 0 0 1 0 0 0 2 8 9 8 0 T o t a l C a r b o n 4 0 0 0 3 9 8 0 3 7 5 0 3 8 3 2 . 5 3 1 6 . 2 5 T I C 2 2 . . 4 1 7 . 2 5 8 . 3 2 0 . 3 2 7 8 TOC 3 9 7 8 3 9 6 3 3 7 4 4 3 8 1 9 3 1 5 . 0 COD 1 2 8 5 4 1 2 8 2 3 1 1 5 1 1 1 1 9 7 7 7 0 6 1 0 C a 4 6 8 1 8 7 0 1 0 6 5 1 0 7 6 7 8 5 - 1 2 7 C u 0 . 0 8 0 . 0 6 3 0 . 0 5 1 0 . 0 5 8 0 . 0 0 6 3 6 F e 5 9 0 9 0 6 6 3 7 . 6 9 8 . 9 K 1 4 7 1 3 8 1 2 6 1 3 5 3 . 4 6 1 4 . 3 Mn 9 . 4 8 6 . 9 0 2 . 5 0 5 . 7 2 0 . 0 9 5 7 3 . 6 N a 1 3 5 1 6 0 1 4 0 1 4 6 . 5 1 0 . 7 - 3 . 7 P 8 . 7 0 0 . 1 8 0 0 . 1 0 8 0 . 1 4 7 0 . 0 2 6 9 8 . 9 P b 0 . 0 3 0 0 . 1 5 4 0 . 0 8 0 0 . 1 1 5 0 . 0 6 3 - 1 6 6 Z n 1 0 . 3 5 0 . 7 0 0 . 0 1 5 0 . 3 5 5 0 . 2 0 9 9 . 8 T S 6 4 4 9 8 7 1 4 8 4 1 6 8 5 2 6 6 2 - 3 0 S S 7 2 3 5 1 2 4 4 1 0 . 4 9 6 . 7 DS 5 7 2 6 8 6 9 0 8 3 6 5 8 4 8 5 6 3 - 4 6 6 1 T A B L E 1 8 R E M O V A L OF S E L E C T E D P O L L U T A N T S FROM L A N D F I L L L E A C H A T E I N E X P E R I M E N T A L GROUP 6 , RUNS 5 7 - 6 1 P o l l u t a n t O r i g i n a l V a l u e o r C o n c e n t r a t i o n i n m g / 1 R a n g e R e s i d u a l a n d M e a n o f C o n c e n t r a t i o n s S t a n d a r d D e v i a t i o n " s " P e r c e n t R e m o v e d ( b e s t ) H i g h L o w M e a n p H 5 . 2 7 1 1 . 4 4 1 0 . 2 5 1 0 . 9 4 0 . 0 1 5 T u r b i d i t y 6 2 5 2 2 . 2 2 5 . 4 4 7 5 9 6 . 4 C o l o u r 1 5 0 0 1 6 5 8 5 1 3 3 2 8 9 9 4 . 3 T C 4 0 0 0 2 8 2 0 2 6 4 0 2 7 0 8 3 1 3 4 T I C 2 2 . 4 4 . 2 0 . 8 1 . 9 2 0 . 3 2 9 6 . 4 TOC 3 9 7 8 2 8 1 6 2 6 3 9 2 7 0 6 3 1 3 4 COD 1 4 3 0 0 1 1 2 5 9 1 0 6 8 7 1 1 0 4 5 7 0 6 2 5 C a 4 5 0 1 7 7 0 1 5 0 0 1 6 2 5 7 8 5 - 2 3 3 C u 0 . 0 6 0 . 0 7 5 0 . 0 3 0 0 . 0 5 2 0 . 0 0 6 -F e 6 6 0 - - - 7 . 6 5 0 K 1 0 9 1 3 8 1 3 4 1 3 6 3 . 4 6 - 2 3 Mn 8 . 7 0 . 1 5 0 . 0 5 0 . 0 8 6 0 . 0 9 5 9 9 . 4 N a 1 2 6 1 1 1 1 1 0 1 1 1 1 0 . 7 1 2 . 7 P 9 . 3 0 . 1 2 5 0 . 0 6 5 0 . 0 8 4 0 . 0 2 6 9 9 . 3 P b 0 . 0 2 3 - - - 0 . 0 6 3 -Z n 9 . 4 0 . 0 3 5 0 . 0 2 0 0 . 0 2 6 0 . 2 0 9 9 . 8 T S 6 0 2 2 1 2 2 8 4 9 1 6 9 9 9 4 8 6 2 - 5 2 S S 8 1 7 8 5 2 6 6 4 0 . 4 9 7 DS 5 2 0 5 1 2 1 9 9 9 1 1 3 9 8 8 2 6 3 - 7 5 6 2 T A B L E 1 9 R E M O V A L OF S E L E C T E D P O L L U T A N T S FROM L A N D F I L L L E A C H A T E I N E X P E R I M E N T A L GROUP 7 , RUNS 5 7 , 6 2 - 6 4 P o l l u t a n t O r i g i n a l V a l u e o r C o n c e n t r a t i o n i n m g / 1 R a n g e R e s i d u a l a n d M e a n o f C o n c e n t r a t i o n s S t a n d a r d D e v i a t i o n " s " P e r c e n t R e m o v e d ( b e s t ) H i g h L o w M e a n P H 5 . 2 6 1 0 . 5 0 1 0 . 2 1 1 0 . 3 4 5 0 . 0 1 5 -T u r b i d i t y 6 2 1 9 2 . 2 1 4 . 5 5 7 5 9 6 . 4 ' C o l o u r 1 5 0 0 1 6 5 1 6 5 1 6 5 2 8 9 8 9 T C 4 0 0 0 2 8 3 0 2 6 6 0 2 7 3 0 3 1 3 4 T I C 2 2 . 4 4 . 2 0 . 7 1 . 7 5 0 . 3 2 9 7 TOC 3 9 7 8 2 8 2 9 2 6 5 5 2 7 2 8 3 1 3 3 COD 1 4 3 0 0 1 1 1 8 0 8 3 8 5 1 0 2 4 7 7 0 6 4 1 C a 4 5 0 1 5 9 0 1 5 0 0 1 5 3 5 7 8 5 - 2 3 3 C u 0 . 0 6 0 . 0 5 6 0 . 0 4 5 0 . 0 5 2 0 . 0 0 6 2 5 F e 6 6 0 - - - 7 6 -K 1 0 9 1 3 8 1 3 4 1 3 7 3 . 4 6 - 2 2 Mn 8 . 7 0 . 0 9 0 . 0 5 . 0 7 0 . 0 9 5 9 9 . 4 N a 1 2 6 1 1 1 1 0 9 1 1 0 1 0 . 7 1 3 P 9 . 3 1 . 9 0 . 0 6 9 0 . 5 4 0 . 0 2 6 9 9 . 2 P b - - - - 0 . 0 6 3 -Z n 9 . 4 0 . 0 3 5 0 . 0 2 0 0 . 0 2 9 0 . 2 0 9 9 . 8 T S 6 0 2 2 9 1 6 9 9 0 4 9 9 1 1 2 6 2 - 5 0 S S 8 1 7 4 7 2 6 3 7 0 . 4 9 7 DS 5 2 0 5 9 1 4 3 9 0 0 2 9 0 7 5 6 3 - 7 3 6 3 T A B L E 2 0 R E M O V A L OF S E L E C T E D P O L L U T A N T S FROM L A N D F I L L L E A C H A T E I N E X P E R I M E N T A L GROUP 8 , RUNS 6 5 - 7 2 P o l l u t a n t O r i g i n a l V a l u e o r C o n c e n t r a t i o n i n m g / 1 R a n g e R e s i d u a l a n d M e a n o f C o n c e n t r a t i o n s S t a n d a r d D e v i a t i o n " s " P e r c e n t R e m o v e d ( b e s t ) H i g h L o w M e a n p H 5 . 2 7 1 0 . 6 1 9 . 2 9 . 8 8 0 . 0 1 5 -T u r b i d i t y 6 2 17 1 4 1 5 . 5 7 5 77 C o l o u r 1 5 0 0 2 5 0 2 0 0 2 1 2 . 5 2 8 9 8 7 T C 4 0 0 0 2 8 7 0 2 7 4 0 2 8 0 6 3 1 3 2 T I C 2 2 . 4 5 . 8 1 . 2 4 2 . 8 0 . 3 2 9 4 TOC 3 9 7 8 2 8 6 9 2 7 3 7 2 8 0 3 3 1 3 1 COD 1 4 3 0 0 1 2 1 3 2 1 0 7 3 7 1 1 3 1 3 7 0 6 2 5 C a 4 5 0 1 6 4 0 1 4 1 0 1 5 1 6 7 8 5 - 2 1 3 C u 0 . 0 6 0 . 0 9 0 . 0 6 5 0 . 0 7 7 0 . 0 0 6 - 8 F e 6 6 0 0 . 9 7 1 0 . 3 0 1 0 . 4 6 7 . 6 9 9 . 9 K 1 0 9 1 7 4 1 3 1 1 5 4 3 . 4 6 - 2 0 N a 1 2 6 1 1 1 1 0 8 1 1 0 . 6 1 0 . 7 1 2 . 7 P 9 . 3 0 . 0 8 7 0 . 0 4 5 0 . 0 6 7 0 . 0 2 6 9 9 . 5 Mn 8 . 7 0 . 0 5 3 0 . 0 3 6 0 . 0 4 3 0 . 0 9 5 9 9 . 6 P b 0 . 0 2 3 0 . 0 6 0 0 . 0 1 1 0 . 0 3 4 0 . 0 6 3 5 2 Z n 9 . 4 0 . 2 0 7 0 . 0 2 4 0 . 0 5 0 0 . 2 0 9 9 . 7 T S 6 0 0 2 9 5 7 7 8 7 4 7 9 1 3 5 6 2 - 4 5 S S 8 1 7 2 5 1 1 1 8 0 . 4 9 8 . 6 DS 5 2 0 5 9 5 6 2 8 7 2 2 9 1 1 7 6 3 - 6 8 6 4 T A B L E 2 1 R E M O V A L OF S E L E C T E D P O L L U T A N T S FROM L A N D F I L L L E A C H A T E I N E X P E R I M E N T A L GROUP 9 , RUNS 7 3 - 8 0 P o l l u t a n t s O r i g i n a l V a l u e o r C o n c e n t r a t i o n i n m g / 1 R a n g e a n d M e a n o f R e s i d u a l C o n c e n t r a t i o n s S t a n d a r d D e v i a t i o n " s " P e r c e n t R e m o v e d ( b e s t ) H i g h L o w M e a n p H 5 . 2 9 1 0 . 1 9 8 . 2 1 8 . 9 7 0 . 3 9 -T u r b i d i t y 6 2 27 1 3 1 8 . 6 1 4 . 9 3 7 9 C o l o u r 8 0 0 5 0 0 1 2 5 2 5 3 2 5 8 4 TC 3 2 1 0 2 6 0 0 2 4 9 5 2 5 6 3 5 3 2 2 T I C 2 6 . 7 1 7 . 8 1 . 4 7 . 5 4 . 4 1 9 5 TOC 3 1 8 3 2 5 9 9 2 4 9 2 2 5 5 5 5 3 2 2 COD 9 9 2 0 1 0 0 5 8 9 0 0 6 9 4 5 3 1 8 2 9 C a 3 3 3 1 2 7 0 1 0 5 0 1 1 8 6 7 2 - 2 1 5 C u 0 . 0 1 9 0 . 0 7 4 0 . 0 5 6 0 . 0 6 6 0 . 0 0 3 - 1 9 4 F e 5 0 0 3 . 4 2 8 0 . 2 8 5 1 . 3 8 0 0 . 4 9 6 9 9 . 9 K 7 8 1 0 2 9 3 9 8 5 . 1 2 - 1 9 N a 8 5 8 5 8 0 8 2 . 4 0 . 3 6 8 5 . 8 P 1 1 . 4 0 . 1 1 5 0 . 0 1 0 . 0 8 1 0 . 3 7 7 9 9 . 9 Mn 7 . 3 4 0 . 7 2 1 0 . 1 0 7 0 . 2 8 3 0 . 0 0 5 9 8 . 5 P b 0 . 0 1 8 0 . 0 2 4 0 . 0 1 1 0 . 0 1 4 0 . 0 1 4 3 9 Z n 6 . 6 0 0 . 0 2 1 0 . 0 1 5 0 . 0 1 7 5 0 . 0 3 6 9 9 . 8 T S 4 8 4 6 7 5 1 6 6 4 6 5 7 1 1 1 1 2 6 - 3 3 S S 8 0 1 2 4 3 1 2 . 4 3 9 9 9 . 6 DS 4 3 2 6 7 4 9 2 6 4 5 3 7 0 9 9 9 3 - 4 9 6 5 T A B L E 2 2 R E M O V A L OF S E L E C T E D P O L L U T A N T S FROM L A N D F I L L L E A C H A T E I N E X P E R I M E N T A L GROUP 1 0 , RUNS 8 1 - 9 6 P o l l u t a n t O r i g i n a l V a l u e o r C o n c e n t r a t i o n i n m g / 1 R a n g e a n d M e a n o f R e s i d u a l C o n c e n t r a t i o n s S t a n d a r d D e v i a t i o n " s " P e r c e n t R e m o v e d ( b e s t ) H i g h L o w M e a n P H 5 . 2 9 1 0 . 5 9 1 0 . 0 1 0 . 2 6 0 . 3 9 -T u r b i d i t y 9 6 3 2 2 6 . 3 8 1 4 . 9 3 9 7 . 9 C o l o u r 1 0 0 0 6 0 0 1 0 0 2 9 4 2 5 9 0 TC 3 1 9 0 3 0 7 5 2 8 0 0 2 9 8 2 5 3 1 2 . 2 T I C 5 6 . 6 3 . 6 0 . 8 2 . 0 0 4 . 4 1 9 8 . 6 TOC 3 1 3 3 3 0 7 3 2 7 9 9 2 9 7 9 5 3 1 1 COD 1 0 0 7 1 9 0 4 5 8 1 2 8 8 5 5 3 1 8 2 1 9 . 3 C a 3 4 9 1 7 8 8 1 5 1 2 1 7 0 2 7 2 - 3 5 4 C u 0 . 0 2 3 0 . 0 5 6 0 . 0 1 7 0 . 0 3 4 0 . 0 0 3 2 6 F e 5 1 0 2 . 0 0 . 1 8 0 . 6 8 0 . 4 9 6 9 9 . 9 K 7 2 1 0 3 8 7 9 4 5 . 1 2 - 2 1 N a 7 6 7 6 . 7 0 7 5 . 1 0 7 5 . 7 6 0 . 3 6 8 1 . 2 P 1 4 . 6 0 . 3 9 0 . 1 3 0 . 1 7 0 . 3 7 7 9 9 . 1 Mn 6 . 4 4 0 . 2 2 0 . 1 0 0 . 1 5 0 . 0 0 5 9 8 . 4 P b 0 . 0 2 5 0 . 0 1 4 0 . 0 0 3 0 . 0 0 8 5 0 . 0 1 4 8 8 Z n 5 . 7 3 0 . 0 1 4 3 0 . 0 0 2 7 0 . 0 0 6 4 0 . 0 3 6 9 9 . 9 T S 4 6 2 3 7 2 9 2 6 9 1 2 7 1 1 0 1 2 6 - 4 9 . 5 S S 5 2 0 4 6 3 1 7 . 6 3 9 9 9 . 4 DS 4 1 0 3 7 2 8 1 6 9 0 7 7 0 8 6 9 3 - 6 8 6 6 T A B L E 2 3 R E M O V A L OF S E L E C T E D P O L L U T A N T S FROM L A N D F I L L L E A C H A T E I N E X P E R I M E N T A L GROUP 1 1 , RUNS 9 7 - 1 0 0 P o l l u t a n t O r i g i n a l V a l u e o r C o n c e n t r a t i o n i n m g / 1 R a n g e R e s i d u a l a n d M e a n o f C o n c e n t r a t i o n s S t a n d a r d D e v i a t i o n " s " P e r c e n t R e m o v e d ( b e s t ) H i g h L o w M e a n P H 5 . 2 9 1 1 . 6 0 1 1 . 5 2 1 1 . 5 7 0 . 3 9 - 1 1 7 T u r b i d i t y 9 6 4 1 7 2 5 . 2 5 1 4 . 9 3 9 2 . 7 C o l o u r 1 0 0 0 1 0 0 8 1 . 5 8 7 . 5 2 5 9 1 TC 3 1 9 0 2 9 8 5 2 8 7 5 2 9 0 7 5 3 9 . 9 T I C 5 6 . 6 9 . 7 5 4 . 4 7 . 5 5 4 . 4 1 9 2 TOC 3 1 3 3 2 9 8 1 2 8 6 6 2 9 1 0 5 3 8 . 5 COD 1 0 0 7 1 8 3 8 0 8 0 3 0 8 2 2 1 1 8 2 2 0 C a 3 4 9 1 9 5 6 1 7 8 8 1 8 7 2 7 2 - 4 1 2 C u 0 . 0 2 3 . 0 3 8 . 0 3 0 . 0 3 3 0 . 0 0 3 - 3 0 F e 5 1 0 1 . 3 0 0 . 1 1 0 . 7 0 0 . 4 9 6 9 9 . 9 K 7 2 9 8 8 6 9 1 5 . 1 2 - 1 9 . 4 N a 7 6 7 7 . 2 7 6 . 3 7 6 . 7 0 . 3 6 8 - 0 . 4 P 1 4 . 6 0 . 2 8 0 . 2 1 0 . 2 3 0 . 3 7 7 9 8 . 5 Mn 6 . 4 4 0 . 0 4 0 . 0 3 0 . 3 2 5 0 . 0 0 5 9 9 . 5 P b 0 . 0 2 5 0 . 0 3 6 0 . 0 1 6 0 . 0 1 7 0 . 0 1 4 3 6 Z n 5 . 7 3 0 . 0 8 3 6 0 . 0 0 2 6 0 . 0 3 0 7 0 . 0 3 6 9 9 . 9 T S 4 6 2 3 7 6 1 3 7 3 3 2 7 4 2 9 1 2 6 - 5 8 S S 5 2 0 1 0 0 1 0 5 4 . 5 3 9 9 8 DS 4 1 0 3 7 5 1 3 7 3 2 2 7 3 7 4 9 3 - 7 8 6 7 T A B L E 2 4 R E M O V A L OF S E L E C T E D P O L L U T A N T S FROM L A N D F I L L L E A C H A T E I N E X P E R I M E N T A L GROUP 1 2 , RUNS 1 0 1 - 1 0 4 P o l l u t a n t O r i g i n a l V a l u e o r C o n c e n t r a t i o n i n m g / 1 R a n g e R e s i d u a l a n d M e a n o f C o n c e n t r a t i o n s S t a n d a r d D e v i a t i o n " s " P e r c e n t R e m o v e d ( b e s t ) H i g h L o w M e a n p H 5 . 2 9 1 1 . 6 3 1 1 . 5 1 1 . 5 6 0 . 3 9 -T u r b i d i t y 9 6 2 8 5 1 4 1 4 . 9 3 9 4 . 8 C o l o u r 1 0 0 0 2 5 0 1 0 0 1 3 7 . 5 2 5 9 0 TC 3 1 9 0 3 0 5 0 2 9 5 0 2 9 9 6 5 3 7 . 5 T I C 5 6 . 6 1 0 . 2 2 . 2 6 . 9 6 4 . 4 1 9 6 TOC 3 1 3 3 3 6 4 9 2 9 4 1 3 2 9 2 5 3 6 . 1 COD 1 0 0 7 1 8 9 3 6 8 3 2 3 8 5 8 2 1 8 2 1 7 . 3 C a 3 4 9 2 0 3 7 1 5 7 5 1 8 4 2 7 2 - 3 6 2 C u 0 . 0 2 3 0 . 0 5 4 0 . 0 2 3 0 . 0 3 6 0 . 0 0 3 0 F e 5 1 0 0 . 9 6 0 . 1 0 0 . 6 3 0 . 4 9 6 9 9 . 9 8 K 7 2 9 7 8 9 9 4 5 . 1 2 - 2 4 N a 7 6 7 7 . 8 7 6 . 7 5 7 7 . 4 0 . 3 6 8 - 1 P 1 4 . 6 0 . 3 4 0 . 0 9 0 . 1 8 0 . 3 7 7 9 9 . 3 Mn 6 . 4 4 0 . 0 5 0 . 0 1 0 . 0 3 0 . 0 0 5 9 9 . 8 P b 0 . 0 2 5 0 . 0 4 3 0 . 0 0 3 0 . 0 2 0 . 0 1 4 8 8 Z n 5 . 7 3 0 . 0 1 7 0 . 0 0 6 0 . 0 1 0 0 . 0 3 6 9 9 . 9 T S 4 6 2 3 7 6 6 3 6 6 3 6 7 3 6 8 1 2 6 - 4 4 S S 5 2 0 7 3 7 2 6 3 9 9 8 . 6 DS 4 1 0 3 7 5 9 0 6 6 2 3 7 3 4 1 9 3 - 6 1 68 to f i n d the average response or e f f e c t of each of the 4 reagents tested, as well as the e f f e c t of the 11 possible reagent in t e r a c t i o n s i n the o v e r a l l response. The "Found Values" shown i n Table 25 are the actual r e s i d u a l values f o r "Colour" i n the Group 4 experiments. The average e f f e c t caused by increasing the dose of each of the applied reagents and in t e r a c t i o n s i s c a l c u l a t e d , the ranking noted i n order of absolute value and then transferred to the numerical l i s t accompanying Figure 14. This data l i s t demonstrates the c a l c u l a t i o n of the Standard Deviation used to f i n d the s i g n i f i c a n t e f f e c t s on the Figure 14 graph. It may be noted that Figure 14 demonstrates the appearance of a half-normal p l o t , when a number of the e f f e c t s of equal si z e are pl o t t e d . These equal e f f e c t s could be plotted as one average e f f e c t located at the average order p o s i t i o n . Figure 14 shows that i n going from a dose of 51 mg/1 to 98 mg/1 of ozone, ozone has the largest average e f f e c t of the reagents tested, that i s , reducing the colour by approximately 2500 u n i t s . Lime also has s i g n i f i c a n t colour-reducing e f f e c t of 2000 colour u n i t s , i n the a p p l i c a t i o n range between 1200 mg/1 and 2000 mg/1. The i n t e r a c t i o n between lime and ozone i n these a p p l i c a t i o n ranges has the e f f e c t of increasing the colour by approximately 1125 colour u n i t s . The three foregoing e f f e c t s of Ozone and Lime deviate i n a s t a t i s t i c a l l y s i g n i f i c a n t manner from a half-normal d i s t r i b u t i o n of nonsignificant e f f e c t s , and may be estimated to occur with a confidence of more than 95 percent. The standard deviation, estimated i n the numerical data accompanying Figure 14, i s d i f f e r e n t from the standard deviation estimated i n Table 16; the l a t t e r i s ar r i v e d at by the r e s u l t s from 3 r e p l i c a t e runs 6 9 T A B L E 2 5 E X A M P L E OF A F A C T O R I A L D E S I G N M A T R I X U S E D I N T H E P O S T - S C R E E N I N G E X P E R I M E N T S W I T H THE M A I N E F F E C T S AND T H E I N T E R A C T I O N E F F E C T S C A L C U L A T E D FOR E A C H OF THE FOUR T R E A T M E N T V A R I A B L E S U S E D I N GROUP 4 ( E F F E C T ON D E P E N D E N T V A R I A B L E — C O L O U R ) D E P E N D E N T V A R I A B L E C o l o u r O R I G I N A L V A L U E 2 5 0 0 H e l i g e U n i t s I N D E P E N D E N T I N T E R A C T I O N S FOUND RUN V A R I A B L E V A L U E N O . m g / 1 A B C D A B A C AD BC BD CD A B C ABD A C D BCD A B C D 3 7 - - - - + + + + + + - - - - + 5 0 0 0 3 8 + + + + + + + - - 1 5 0 0 3 9 - + - - - + + - - + + + - + - 5 0 0 0 4 2 + + - - + - - - - + - - + + + 1 5 0 0 4 0 - - + - + - + - + - + - + + - 5 0 0 0 4 3 + - + - - + - - + - - + - + + 1 5 0 0 4 5 - + + - - - + + - - - + + - + 4 0 0 0 4 8 + + + - + + - + - - + - - - - 2 0 0 0 4 1 - - - + + + - + - - - + + + - 1 0 0 0 4 4 + - - + - - + + - - + - - + + 2 5 0 4 6 - + - + - + - - + - + - t - + 1 5 0 0 4 9 + + - + + - + - + - - + - - - 2 5 0 4 7 - - + + + - - - - + + + - - + 1 0 0 0 5 0 + - + + - + + - - + - - + - - 2 5 0 5 1 - + + + - - - + + + - - - + - 1 0 0 0 5 2 + + + + + + + + + + + + + + + 2 5 0 Effects -2000 1 o -125 -2500 LO CN H o LO CN 1125 -125 LO CN H o LO CN -250 -125 o -125 R a n k 1 4 3 9 1 5 8 1 2 1 3 7 6 2 1 1 1 0 5 1 4 70 i n Group 4- and i s used as the estimate of the standard deviation f o r the "Found Values" of the 16 experiments of Group 4-. The standard deviation of the responses ("Found Values") and average e f f e c t s are r e l a t e d by the equation: Standard Deviation of e f f e c t Standard Deviation of response Number of runs at high l e v e l reagent dose Number of runs at Low Level reagent dose While some d i s p a r i t y may be noted i n some of these estimates of the standard deviation of e f f e c t s by the two methods, i n no case would the f i n a l i n t e r p r e t a t i o n of the results be d i f f e r e n t i n these experiments. Group 2 data was analyzed i n the manner described i n the foregoing but, because of the missing data points from the missing runs noted i n Table 9, the r e s u l t s of the analysis was only used to confirm the data from the complete group. Where three applied independent variables were used, as i n Groups 8 and 9 (re q u i r i n g only 8 runs to include a l l p o ssible combinations of those three variables at two l e v e l s ) , one h a l f of the matrix i n Table 25 was used. P l o t t i n g of the calculated e f f e c t s on a half-normal p l o t , f o r determination of the s i g n i f i c a n t e f f e c t s was performed i n the same manner as f o r the 4- independent va r i a b l e groups. where s^ . s r nH n L 7 1 0 2 4 6 8 10 II 12 13 14 15 ORDER NUMBERS ORDER EFFECT ABSOLUTE z (VALUE HZ) (Z) 2 NUMBER NAME VALUE 1 BCD 0 0 . 0 7 9 0 0 . 0 0 6 2 4 1 2 CD 0 0 . 1 5 8 0 0 . 0 2 4 9 6 4 3 B 0 0 . 2 3 9 0 0 . 0 5 7 1 2 1 4 A B C D 1 2 5 0 . 3 2 2 4 0 . 2 5 0 . 1 0 3 6 8 4 5 ACD 1 2 5 0 . 4 0 8 5 1 . 0 0 0 . 1 6 6 4 6 4 6 BD 1 2 5 0 . 4 9 6 6 2 . 0 0 0 . 2 4 6 0 1 6 7 B C 1 2 5 0 . 5 8 9 7 3 . 6 2 5 0 . 3 4 6 9 2 1 8 A B 1 2 5 0 . 6 8 8 8 6 . 0 0 0 . 4 7 3 3 4 4 9 C 1 2 5 0 . 7 9 4 9 9 . 2 5 0 . 6 3 0 4 3 6 1 0 A B D 2 5 0 0 . 9 1 0 2 2 7 . 5 0 0 . 8 2 8 1 0 0 1 1 A B C 2 5 0 1 . 0 4 0 2 6 0 . 0 0 1 . 0 8 1 6 0 0 1 2 AC 2 5 0 1 8 9 9 . 6 2 5 1 3 . 9 6 4 8 9 1 1 3 AD 1 1 2 5 1 4 A 2 0 0 0 E ( V A L U E ) ( Z ) 1 5 D 2 5 0 0 s = E ( Z 2 ) 8 9 9 . 6 2 5 3 . 9 6 4 8 9 1 = 2 2 6 . 8 9 7 7 8 F i g u r e 1 4 . E x a m p l e o f t h e h a l f - n o r m a l p l o t o f t h e a b s o l u t e v a l u e s o f t h e c a l c u l a t e d d e p e n d e n t v a r i a b l e e f f e c t s o n c o l o u r w i t h r e l a t e d s t a n d a r d d e v i a t i o n c a l c u l a t i o n ( n a m e c o d e i n a c c o r d a n c e t o T a b l e 1 4 ) 72 7.4 Discussion of Post-Screening Experimental Data While Tables 9 to 24 summarily describe the experiments and r e s u l t s of the post-screening experimental programme, added discussion of the e f f e c t s of the treatment on the i n d i v i d u a l pollutants monitored i s given i n the following (and summarized i n Table 26): pH. The "best value" chosen f o r pH i s the value clos e s t to neutral (pH 7). This best value occurred i n Group 4, Run 38 and f o r t h i s group the most s i g n i f i c a n t cause of pH adjustment was lime. In Group 4 ozone also contributed s i g n i f i c a n t l y to pH adjustment, r a i s i n g the pH, as would be expected, where both the o r i g i n a l and treated leachate pH i s at or below neutral (see also p. 46, Section 7.2, Ozone). The adjustment of pH i s a c r i t i c a l step i n the removal of many pollutants by chemical p r e c i p i t a t i o n and f o r t h i s type of adjustment lime i s the most e f f e c t i v e reagent of those used i n t h i s i n v e s t i g a t i o n . T u r b i d i t y . The best value f o r t u r b i d i t y was produced i n Group 10, Run 85, with a lime dose of 2350 mg/1. There was no s i g n i f i c a n t added t u r b i d i t y removal by increasing the ozone dose up to 248 mg/1 i n the Group 10 experiment. Ozone had been shown to e f f e c t s i g n i f i c a n t t u r b i d i t y removal i n Group 4 when the ozone dose was increased from 51 to 98 mg/1; therefore, i t i s considered that, f o r t h i s p a r t i c u l a r leachate, the e f f e c t i v e ozone dose i s i n t h i s range f o r t u r b i d i t y removal. Colour. The s t a t i s t i c a l analyses of the r e s i d u a l colour measurements obtained indi c a t e that lime e f f e c t s a s i g n i f i c a n t reduction i n colour i n the dose range 0 to 2000 mg/1, but that the most e f f e c t i v e colour reduction was by ozone. Unlike t u r b i d i t y , f o r which the most e f f e c t i v e ozone range was between 51 mg/1 and 98 mg/1, the colour reducing 73 effectiveness of ozone continued well above doses of 98 mg/1; t h i s was demonstrated i n experimental Groups 8 and 10 with h i g h - l e v e l ozone doses of 130 mg/1 and 24-8 mg/1, r e s p e c t i v e l y . R e p r o d u c i b i l i t y of colour measurements was not good, with, standard deviations larger than "best low" measurements. The treated leachate samples with the low colour measurements were v i s u a l l y acceptable. T o t a l Carbon. The T o t a l Carbon content of the leachate was not greatly reduced by the treatments used. The best T o t a l Carbon removal was 38 percent, while the "best value" i n the treated leachate was 2495 mg/1, corresponding to a 22 percent removal rate f o r that sample. Lime, i n a l l cases, acted as an i n h i b i t o r of T o t a l Carbon removal. The only e f f e c t i v e removal agent was ozone and the amount removed by ozone was d i r e c t l y a f f e c t e d by the amount of lime added. Overall T o t a l Carbon removed was not s u f f i c i e n t to produce an acceptable treated leachate e f f l u e n t . T o t a l Inorganic Carbon. Low T o t a l Inorganic Carbon r e s i d u a l s were obtained throughout the experimental programme. It was not p o s s i b l e , from the s t a t i s t i c a l a n a l y s i s , to name any one applied reagent as e f f e c t i v e i n causing the removal of inorganic carbon. T o t a l Inorganic Carbon was a r e l a t i v e l y small part of the T o t a l Carbon contained i n the untreated leachate, generally less than 2 percent. The "best value" was obtained i n Group 10, Run 96, with a r e s i d u a l of 0.8 mg/1 and a 98.6 percent removal rate. The low r e s i d u a l s indicate that the carbonate i n the added lime reagent was not r e s i d u a l i n the treated leachate. T o t a l Organic Carbon. T o t a l Organic Carbon represented more than 98 percent of the T o t a l Carbon i n the leachate; therefore, the r e s u l t s f o r T o t a l Organic Carbon are nearly i d e n t i c a l to the r e s u l t s f o r T o t a l Carbon. 74 Chemical Oxygen Demand. The "best low value" f o r Chemical Oxygen Demand was obtained i n Group 11, Run .97, with a r e s i d u a l of 8030 mg/1 and a 20 percent removal rate; the best e f f i c i e n c y of removal was i n Group 7, Run 63, at 41 percent. It should be noted that the untreated leachate contained Suspended Solids that were s e t t l e a b l e without treatment or by f l o c c u l a t i o n alone. These Suspended Solids probably contain a considerable part of the COD present (possibly also TC) i n the untreated leachate. The COD removal e f f e c t of these s e l f - s e t t l i n g Suspended Solids i s not apportioned to any chemical reagent, and may be the r e a l cause of the "best low value." The i n d i c a t i o n that s e t t l i n g may be the cause of the best value i s that the most e f f i c i e n t removal r a t e , of 41 percent i n Run 63, was shown to have been effected by lime when the lime dose was increased from 2100 mg/1 to 2900 mg/1. The lime dose f o r Run 97 was 2350 mg/1 with no removal effectiveness shown f o r lime. From the foregoing, i t i s very probable that the lime dose range f o r removal of COD i s near 2900 mg/1. Calcium. There was no e f f e c t i v e removal of calcium. The "best low value" f o r calcium was the r e s u l t of a zero lime dose. Lime was shown to e f f e c t i v e l y increase the calcium content of the treated leachate. Copper. Copper was only removed by lime. The most e f f e c t i v e lime dose range was between 1200 to 2000 mg/1. The i n t e r a c t i o n between lime and ozone was shown to i n h i b i t copper removal. This i n h i b i t i o n of copper removal by the lime-ozone i n t e r a c t i o n may confirm that the findings of other investigators (27) whereby the pH adjustment of ozone i s always towards neutral. P r e c i p i t a t i o n and consequent removal of copper by lime i s a function of pH; i f ozone lowers the pH then t h i s would account f o r 75 the i n h i b i t i n g i n t e r a c t i o n . Iron. The "best low value" f o r iron was i n Group 12, Run 104-, with a low of 0.01 mg/1 of r e s i d u a l Fe and a removal rate of 99.9 percent. The lime dose was 2350 mg/1 and the ozone dose 181 mg/1 f o r t h i s run. The found e f f e c t i v e dose ranges, on an i n d i v i d u a l reagent b a s i s , were f o r lime, between 1200 and 2000 mg/1, and f o r ozone between 0 and 98 mg/1, i n Group 4- and Groups 1 and 4 r e s p e c t i v e l y . Potassium. The best "apparent" removal rate f o r Potassium was 25 percent where 152 mg/1 of K appeared to be removed. The e f f e c t i v e removal was caused by ozone i n the dose range of 51 to 98 mg/1. In Group 8, with the ozone dose r a i s e d from 108 to 130 mg/1, the removal rate was lowered; that i s , removal was less at 130 mg/1 ozone than at 108 mg/1. Since, i n most of the found r e s u l t s , K re s i d u a l s i n the treated leachate were higher than i n the o r i g i n a l untreated leachate, the found values f o r K are suspect but the e f f e c t i v e removal ranges are not a f f e c t e d . Manganese. The "best low value" f o r Manganese was 0.01 mg/1 (99.8 percent removed) found i n Group 12, Run 104, with a lime dose of 2350 mg/1 and an ozone dose of 181 mg/1. The e f f e c t i v e dose ranges f o r lime and ozone were f o r lime 1600 to 2000 mg/1 and f o r ozone 51 to 98 mg/1. An e f f e c t of low s i g n i f i c a n c e was found to continue into the ozone dose range of 96 to 248 mg/1, which may indicate that the e f f e c t i v e range of ozone f o r manganese removal may be something more than 98 mg/1. Sodium. Behaviour of Sodium, i n the leachate under treatment was not d e f i n i t i v e ; i n some cases there was an apparent removal but the e f f e c t s a t t r i b u t a b l e to any reagent were of low s i g n i f i c a n c e and caused by int e r a c t i o n s between the applied reagents. The "best low value," found i n Group 10, Run 93, was 75.1 mg/1 Na with an apparent removal rate 76 of 1.2 percent. A higher removal rate was found i n one of the screening runs, but Na was not found to be s i g n i f i c a n t l y removed by any f a c t o r applied i n the screening group. Phosphorus. Phosphorus responds r e a d i l y to pH adjustment by lime, with an e f f e c t i v e removal by lime occurring i n the 0 to 1220 mg/1 range. Ozone showed no e f f e c t on P removal, while f e r r i c s u l f a t e had a low s i g n i f i c a n c e e f f e c t , depressing the removal of P. The "best low value" was found i n Group 9, Run 75, with a low of 0.01 mg/1 and a removal rate of 99.9 percent from an untreated leachate with 11.4 mg/1 phosphorus. Lead. Lead appeared to be removed up to 88 percent from an o r i g i n a l value of 0.025 mg/1. This high removal rate from an o r i g i n a l , quite low concentration, occurred i n Group 10, Runs 84, 86, 87, 88, 90 and 92, and i n Group 12, Run 101. For each of these runs the lime dose was 2350 mg/1 and ozone doses were Run 87--97 mg/1, Runs 84, 86, 88 and 90—248 mg/1, Run 101—0 mg/1. This would indi c a t e that lime was the removing agent and, because increasing the lime dose higher than 1200 mg/1 i n any of the post-screening experiments did not produce a s i g n i f i c a n t increase i n the removal of Pb ( e f f e c t ) , i t may be assumed that t h i s was the e f f e c t i v e dose. I t may be noted that, i n going from 1600 to 2000 mg/1 of applied lime i n the Group 5 experiments, the average removal of Pb decreased. Zinc. The "best low value" found f o r zinc occurred i n Group 5, Run 56; removal rates were high, that i s , between 98 and 99.9 percent, i n a l l cases. S i g n i f i c a n t l y e f f e c t i v e Zn removals were e n t i r e l y due to treatment with lime, with the s i g n i f i c a n t removals i n the 0 to 2000 mg/1 lime dose range. Ozone had no removal e f f e c t but a c a t i o n i c polymer seemed 77 to have an e f f e c t of low s i g n i f i c a n c e , i n the Group 10 experiments. To t a l S o l i d s . T o t a l s o l i d s were not decreased i n any treatment but instead were increased; an exception to t h i s occurred when there was no added lime. The r e s i d u a l t o t a l s o l i d s increased with larger lime doses. Suspended S o l i d s . Lime was e f f e c t i v e i n suspended s o l i d s removal over a wide dose range, from 1200 to 2900 mg/1 of lime. The "best low value" f o r SS of 3 mg/1 was found i n Group 9, Run 77, with a 99.6 percent removal rate. Ozone had a s i g n i f i c a n t removal e f f e c t when the dose was increased from 51 to 98 mg/1 and the lime dose was at 1200 and 2000 mg/1. Dissolved S o l i d s . Dissolved s o l i d s were increased i n the treated leachate i n a l l experimental runs when the treatment involved lime. Ozone had a s i g n i f i c a n t removal e f f e c t when the applied dose was increased from 51 to 98 mg/1. The le a s t increase i n dissolved s o l i d s occurred i n Group 4, Run 51, when the lime dose was 1200 mg/1 and the ozone dose was 98 mg/1. 7.5 Data—Ozone D i s i n f e c t i o n Table 27 displays the data r e s u l t i n g from the b a c t e r i o l o g i c examination of samples of ozonated leachate. The data of Table 27 i s shown i n accordance with recording procedure prescribed by Standard Methods (18). 7.6 Discussion of D i s i n f e c t i o n Data Two obvious anomalies appear i n the r e s u l t s of Table 27. 7 8 T A B L E 2 6 SUMMARY OF B E S T LOW R E S I D U A L S O B T A I N E D ' W I T H R E A G E N T D O S E S AND DOSE R A N G E S A S I N D I C A T E D C H A R A C T E R I S T I C LOW R E S I D U A L RUN E F F E C T I V E T R E A T M E N T DOSE OR R A N G E ( B E S T V A L U E ) N O . L i m e O z o n e p H ( 1 ) ( 2 ) 6 . 9 p H J n i t s 3 8 2 0 0 0 m g / 1 5 1 m g / 1 T u r b i d i t y ( 2 ) 2 H a c h U n i t s 8 5 2 3 5 0 m g / 1 5 1 - 9 8 m g / 1 C o l o u r ( 4 ) 5 0 c o l o u r U n i t s 1 0 0 1 2 0 0 - 2 0 0 0 m g / 1 5 1 - 2 4 8 m g / 1 T C ( 2 ) 2 4 9 5 m g / 1 7 8 2 6 3 0 m g / 1 5 1 - 9 8 m g / 1 T I C ( 3 ) 0 . 8 m g / 1 9 6 2 3 5 0 m g / 1 2 4 8 m g / 1 TOC ( 2 ) 2 4 9 2 m g / 1 7 8 2 6 3 0 m g / 1 5 1 - 9 8 m g / 1 COD ( 2 ) 8 0 3 0 m g / 1 9 7 2 3 5 0 m g / 1 5 1 - 9 8 m g / 1 C a ( 1 ) ( 2 ) 3 5 0 m g / 1 1 4 0 1 3 m g / 1 C u ( 4 ) 0 . 0 1 7 m g / 1 9 0 1 2 0 0 - 2 0 0 0 m g / 1 5 1 - 9 8 m g / 1 F e ( 4 ) 0 . 1 0 m g / 1 1 0 4 1 2 0 0 - 2 0 0 0 m g / 1 0 - 5 0 m g / 1 K ( 3 ) 1 1 4 m g / 1 5 1 1 2 0 0 m g / 1 9 8 m g / 1 Mn ( 4 ) 0 . 0 1 m g / 1 1 0 4 1 2 0 0 - 2 0 0 0 m g / 1 5 1 - 9 8 m g / 1 N a ( 3 ) 7 5 . 1 m g / 1 9 3 2 3 5 0 m g / 1 9 8 m g / 1 P ( 2 ) 0 . 0 1 m g / 1 7 5 0 - 2 0 0 0 m g / 1 1 1 m g / 1 P b ( 1 ) ( 5 ) 0 . 0 0 3 m g / 1 8 4 2 3 5 0 m g / 1 2 4 8 m g / 1 Z n ( 2 ) ( 4 ) 0 . 0 0 2 6 m g / 1 9 7 1 2 0 0 - 2 0 0 0 m g / 1 1 5 8 m g / 1 T S ( 2 ) ( 4 ) 7 0 0 6 m g / 1 5 1 1 2 0 0 m g / 1 5 1 - 9 8 m g / 1 S S ( 4 ) 3 m g / 1 77 1 2 0 0 - 2 9 0 0 m g / 1 5 1 - 9 8 m g / 1 DS 6 9 4 6 m g / 1 5 1 1 2 0 0 m g / 1 5 1 - 9 8 m g / 1 N o t e s : ( 1 ) U n d e r l i n e d d o s e i s s i n g l e e f f e c t i v e d o s e . ( 2 ) D o s e n o t u n d e r l i n e d i s d o s e a t w h i c h l o w r e s i d u a l a c h i e v e d . ( 3 ) B o t h d o s e s n o t u n d e r l i n e d i n d i c a t e s n o d o s e r a n g e d e t e r m i n e d . ( 4 ) R a n g e o f d o s e u n d e r l i n e d i n d i c a t e s r a n g e a t w h i c h r e a g e n t w a s f o u n d t o b e e f f e c t i v e . E f f e c t i v e d o s e i n l o w r e s i d u a l r u n m a y b e i n t h i s r a n g e o r g r e a t e r . ( 5 ) S e e Q u a l i f i c a t i o n i n t e x t o n p . 7 1 . T A B L E 27 ' S T A N D A R D P L A T E COUNTS AT 3 5 ° C FOR L E A C H A T E T R E A T E D W I T H OZONE ( C O D o f 1 4 , 3 0 0 m g / 1 ) P l a t e N o . D i l u t i o n M g / 1 0 3 D o s e C o l o n i e s C o u n t e d 1 1 : 1 0 1 7 2 1 : 1 1 0 M o r e t h a n 3 0 0 3 1 : 1 2 0 M o r e t h a n 3 0 0 4 1 : 1 3 0 M o r e t h a n 3 0 0 5 1 : 1 4 0 M o r e t h a n 3 0 0 6 1 : 1 8 9 M o r e t h a n 3 0 0 7 1 : 1 1 0 2 M o r e t h a n 3 0 0 8 1 : 1 1 3 7 2 7 0 9 1 : 1 1 6 3 M o r e t h a n 3 0 0 1 0 t o 1 8 1 : 1 £ 1 : 1 0 1 1 0 A v e r a g e 7 80 F i r s t l y , Plate No. 1, with no applied ozone, shows a r e l a t i v e l y low microbial colony count. A c r i t i c a l examination of the procedures used determined that i t was possible that t h i s low count may have been caused by r e s i d u a l d i s i n f e c t a n t ( c h l o r i n e ) , c o l l e c t i n g i n the sample d r a i n - o f f l i n e leading from the ozone contacting cylinder ( l e f t from the washing and d i s i n f e c t i o n of the apparatus p r i o r to the t e s t ) . Secondly, because of the prescribed method of recording the plate counts, Nos. 2 to 9 do not show a d i s t i n c t point at which b a c t e r i a l k i l l occurred, i . e . , between PlatesNos. 7 and 8. However, v i s u a l examination of these plates indicated that a noteworthy change i n b a c t e r i a l density had occurred, v i z . , between the 102 and 137 mg/1 ozone doses. The choice of 110 mg/1 ozone dose-for plates 10 to 18 was made on the basis of the foregoing change i n density, as the approximate ozone dose f o r b a c t e r i a l k i l l . The plate counts f o r Plates Nos. 10 to 18 confirm that the 110 mg/1 ozone dose was s u f f i c i e n t to produce a s a t i s f a c t o r i l y d i s i n f e c t e d leachate. The high colony count f o r Plate No. 9, at 163 mg/1 ozone dose, was not obviously explainable, but was discounted as an errant high. The leachate samples f o r Plates Nos. 10 to 18 were drawn o f f from the leachate r e c i r c u l a t i o n system, thereby preventing the contamination experienced i n the previous sampling. 7.7 General Discussion The data produced from t h i s i n v e s t i g a t i o n i s not considered to be d e f i n i t i v e f o r a l l leachates because of the extreme v a r i a b i l i t y possible i n the constituent make-up of l a n d f i l l leachate. The data generally confirms the findings of other investigators (28, 29) i n that many m e t a l l i c 81 p o l l u t a n t s , with a valence of two or more, may be removed by pH-adjusted p r e c i p i t a t i o n . The degree of removal was most probably governed by the chemical e q u i l i b r i u m of the waste water components and the added reagents, and the e f f e c t of t h i s e q u i l i b r i u m on the s o l u b i l i t y products of the p r e c i p i t a t i n g ion-product substances. There was some concurrent removal by ozone. I n v e s t i g a t e d i n t h i s p r o j e c t were these m u l t i v a l e n t m e t a l l i c s : Cu, Fe, Mn, P, Pb, and Zn. By r e f e r r i n g to Table 26, i t i s p o s s i b l e t o determine the range of " l e v e l s " of a p p l i e d lime and ozone i n which the m e t a l l i c removals were s i g n i f i c a n t . There was no s i g n i f i c a n t removal of K and Na, u n i v a l e n t m e t a l l i c i o n s . Ca, a b i v a l e n t m e t a l l i c , was, i n some dose ranges, s i g n i f i c a n t l y increased i n the t r e a t e d leachate by the use of lime. T o t a l carbon, c o n s i s t i n g of mostly organic carbon, and contained i n the leachate as both d i s s o l v e d and suspended s o l i d s , was only p a r t i a l l y removed by the treatment methods used i n these i n v e s t i g a t i o n s . Therefore, i t was not p o s s i b l e t o produce an acceptable e f f l u e n t f o r discharge to a n a t u r a l r e c e i v i n g water, even though Table 26 shows th a t s i g n i f i c a n t e f f e c t i v e removals were accomplished. Colour and t u r b i d i t y were removed mainly by ozone, although lime was somewhat e f f e c t i v e as w e l l . This colour removal by lime takes place i n a narrow range of pH adjustment, made by i n c r e a s i n g the lime dosage from 1200 t o 2000 mg/1 (pH 6.05-8.5). Lime "colour removal" was probably due, i n p a r t , to the change i n the form of the Fe present, t h a t i s , from the f e r r o u s to the f e r r i c form. This p a r t i c u l a r colour removal may be a t t r i b u t e d to the f o l l o w i n g . Because the leachate used i n these experiments was ozonated by i n t r o d u c i n g ozone i n an oxygen c a r r i e r , before the pH adjustment w i t h 82 lime, the leachate entering the lime treatment stage was highly oxygenated. Ferrous i r o n i s oxidized to the f e r r i c form i n accordance with (16): 2 F e + + + j 0 2 + 5H20 -»• 2Fe(0H) 3 (s) + 4H An examination of a s o l u b i l i t y chart f o r Fe(OH) 3 and the various other t r i v a l e n t - i r o n components ( f o r example, see page 29-17 Ref. (16)) indicates that the s o l u b i l i t y of Fe(OH) 3 (s) i s at a minimum i n the approximate pH range under discussion, with a consequent increase i n the combined t r i v a l e n t i r o n , i o n i c species Fe(OH)^ , Fe(OH)* and Fe(OH) + +. Organic colour, such as that i n leachate, probably i s r e l a t e d to humic substances. Chemically, these humic substances are polymeric compounds with carboxylic f u n c t i o n a l groups. Chemical i n t e r a c t i o n s account f o r colour removals by t r i v a l e n t i r o n . Together with OH ions, the f u n c t i o n a l groups of colour anions occupy coordinative s i t e s of the t r i v a l e n t - m e t a l i o n i c species (16). Anionic, nonionic, and c a t i o n i c p o l y e l e c t r o l y t e s were tested i n doses of 0.5, 1.0, and 2.0 mg/1, but none were found to s i g n i f i c a n t l y increase any pollutant removals. However, since polymers serve as s e t t l i n g or f l o c c u l a t i o n aids by increasing the f l o e s i z e and improving the s e t t l i n g c h a r a c t e r i s t i c s of the r e s u l t i n g sludge, t h i s noneffect may be used as an i n d i c a t i o n that the p h y s i c a l processes used ( s t i r r i n g and s e t t l i n g ) were working well. The ozone d i s i n f e c t i o n data was discussed i n the previous section. This data confirmed the a b i l i t y of ozone to d i s i n f e c t wastewaters noted by others (11, 27). Others have also noted that ozone doses as small as 83 1 to 2 mg/1 can e f f e c t i v e l y d i s i n f e c t drinking water. Wastewaters, contaminated with -a high concentration of BOD or COD, require larger doses f o r d i s i n f e c t i o n , although t h i s has been reported as "time to k i l l " (25). Analysis of the data f o r the experiments reported on here indi c a t e that there i s an ordered sequence of ozone p r i o r i t i e s by the contaminating wastewater constituents. During t h i s ozone p r i o r i t y sequence, the reaction of ozone i s very r a p i d , that i s , i n s t a n t l y with the t r a n s f e r of the ozone to the wastewater. This rapid reaction of ozone continues up to and beyond the order p o s i t i o n at which microorganisms are destroyed. 7.8 Application of the Results to Predict Ozone Requirements Much of the i n v e s t i g a t i o n c a r r i e d out i n t h i s programme was concerned with f i n d i n g the dose at which applied reagents were most e f f e c t i v e i n removing or a l t e r i n g selected c h a r a c t e r i s t i c s of the leachate wastewater. Knowing these l e v e l s can only be u s e f u l i f they can be correlated to some measurable c h a r a c t e r i s t i c of the leachate and to some unique, u s e f u l c h a r a c t e r i s t i c of the p o l l u t i n g substance. Where lime i s the applied reagent, the measurable wastewater character i s the product pH, and the u s e f u l , unique, known c h a r a c t e r i s t i c of the po l l u t a n t i s i t s hydroxide-form, s o l u b i l i t y product. At t h i s time, l i t t l e i s known of the ozone requirements necessary to promote removals or desirable changes of pollutants i n any wastewater. For the purpose of formulating a method f o r p r e d i c t i n g the ozone require-ment to tre a t leachate, to remove any s p e c i f i c m e t a l l i c p o l l u t a n t , COD was chosen as the measurable leachate c h a r a c t e r i s t i c that w i l l be used as the reference base f o r the leachate. The r a t i o obtained by d i v i d i n g the 84 given metal's valence by i t s i o n i c radius i n Angstrom units (A), was the unique and useful c h a r a c t e r i s t i c chosen f o r the m e t a l l i c p o l l u t a n t s . The r a t i o n a l e f o r the foregoing ozone-related choices i s as follows: COD i s an estimate of the a b i l i t y of the organics i n a wastewater to reduce a strong oxidant (dichromate). However, the t e s t does not measure a l l , or only, the organic compounds, but rather the wastewater's a b i l i t y to reduce the chemical oxidant. Many inorganic substances c o i n c i d e n t a l l y reduce the oxidant as w e l l . Since ozone i s also a strong chemical oxidant, the use of COD, as a measure of the effectiveness of ozone as an oxidant, i s cognately u s e f u l . Valence, i n chemistry, i s a property of an element that determines the number of other atoms with which the atom of the element can combine. The s i z e of an ion i s a function of an ion's nuclear p o s i t i v e charge i n r e l a t i o n to the t o t a l negative charge of the electrons surrounding that nucleus. There w i l l be an a t t r a c t i v e force between two adjacent ions, where one has a preponderant p o s i t i v e charge and the other a negative charge. Thus, an ion's s i z e , as measured by i t s radius, i s an important f a c t o r i n the chemical r e a c t i v i t y of an ion (14). The c a l c u l a t i o n of the a c t i v i t y , or more s p e c i f i c a l l y t h e " a c t i v i t y c o e f f i c i e n t , " f o r an ion i n aqueous s o l u t i o n , may be made approximately from the summary "DeBye-Huckle" equation (.16): 2 y log f± = 0.5Z i -1 + \{'-(4) 85 i n which: f\ = the r a t i o of the a c t i v i t y to the molar concentration = the e l e c t r o n i c valence of the ion y - the i o n i c strength as defined by the following equation (31). 2 y = 0.5Ei c i Z i (5) where: -c^ = the molarity of the i^1 ion Z^ = the valence of the i i o n . The complete equation from the "DeBye-Hu'ckle" theory more e f f e c t i v e l y demonstrates the u t i l i t y of the valence-ionic radius r a t i o , f o r describing the a c t i v i t y of an ion i n an aqueous s o l u t i o n : 2 k 0.511 x zi + y 2 l Q g m f 1 0 1 o V 1 + 0.329 x v x y 2 where: f ^ , Z^ , y are as above and f" = the i o n i c radius i n Angstrom units (A). C a l l i n g i t the " i o n i c p o t e n t i a l , " the r a t i o of i o n i c charge (valence) to i o n i c radius i n Angstrom units (A) was f i r s t put forward by Goldschmitt (.12), to explain the d i s t r i b u t i o n of elements between sediments and sea water. On the basis of t h e i r i o n i c p o t e n t i a l , the elements are divided into three groups, which become separated from one another during 86 sedimentation i n the sea. The cations, with low i o n i c p o t e n t i a l ( l e s s than three), generally remain i n i o n i c s o l u t i o n . Intermediate i o n i c p o t e n t i a l ions, i n the range of 3 to 12, have hydroxy1 bonds i n t h e i r hydroxides and are deposited as hydrolysates. The elements with higher i o n i c p o t e n t i a l s , generally greater than 12, form complex anions with oxygen and these usually remain i n s o l u t i o n . Nitrogen, carbon, sulphur and phosphorus belong to t h i s group. It i s also known that the metals which have a small atomic or i o n i c radius are more active i n complex ion formation (30). From the peri o d i c t a b l e , the metals with atomic numbers 24- through 30, that i s , Cr, Mn, Fe, Co, N i , Cu and Zn, with i o n i c r a d i i i n the range of 0.64 A to 0.80 A, have a much greater tendency to form complexes than those with larger i o n i c r a d i i such as K and Ca, with i o n i c r a d i i 1.33 A and 0.99 A, re s p e c t i v e l y . The process of "complex forming" i s also enhanced by the ele c t r o n e g a t i v i t y of the ligand or electron donor and conversely the s i z e of the p o s i t i v e charge on the metal cation. Ozone i s the strongest known oxidant, much used i n research and industry to break or destroy organic ligands. At the same time, ozone i s a ready donor of electrons and may be expected to oxidize such hydroxo-complexes, v i z . : The hydroxo-complex would form i n a neutral to basic so l u t i o n as A l + + + + OH" ^  A1(0H)++ while a s i m p l i f i e d ozone rea c t i o n on mixing with water, 0o + Ho0 - 20H~ + 0o+ 87 followed by the combination r e a c t i o n , A1(0H) + + + 20H~ A l ( 0 H ) 3 ( s ) . The reaction by ozone with hydroxo- and organo-metal complexes may account f o r some of ozone's ready r e a c t i v i t y when mixed with the leachate. In these experiments, the ozone dose was kept within the l e v e l that would t r a n s f e r and be reacted i n the residence time of the oxygen-c a r r i e r gas, i n the contact c y l i n d e r (see Figure 13). When ozone was applied at up to 248 mg/1 to the leachate, with a COD concentration of approximately 10,000 mg/1, a l l of the ozone was transferred to the leachate. At more than 24-8 mg/1, some of the ozone exited the contact c y l i n d e r with the carrier-oxygen stream, i n d i c a t i n g a slower reaction rate between the*ozone and the remaining ozone-reacting substances. The u t i l i t y of staying within the above-mentioned ozone dose w i l l be discussed i n Section 7.9. The nomographic chart shown i n Figure 15 was constructed to possibly provide a quick and simple method of p r e d i c t i n g the ozone dose required to both increase the metal removal i n a lime-induced, pH-adjusted p r e c i p i t a t i o n , and to d i s i n f e c t the treated wastewater. The construction of t h i s chart may be c r i t i c i z e d i n that only two points, from the generated data, were used to p o s i t i o n the diagonal l i n e i n d i c a t i n g the ozone-to-COD r a t i o , and thereby, the ozone dose necessary to oxidize some me t a l l i c p o l l u t a n t s , and to d i s i n f e c t the leachate. In Figure 15, ozone i s given i n mg/1 while COD i s i n grams/1. In accordance with Goldschmitt's (12) presentation, the elements with a small (less than: 3) i o n i c p o t e n t i a l are not r e a d i l y oxidized. In 88 CODg/ l FIG 15 » CHART FOR ESTIMATING OZONE DOSE REQUIRED TO OXIDIZE CERTAIN METALLIC IONS AND LIVING ORGANISMS. 89 t h i s work, t h i s was confirmed f o r those elements monitored—Na, K and Ca. For the elements with an i o n i c p o t e n t i a l greater than 12, such as carbon (C), some removals were noted but i t may be that t h i s was due, i n part, to mechanical removal i n s e t t l i n g . The intermediate i o n i c p o t e n t i a l m e t a l l i c s ( i o n i c p o t e n t i a l 3 to 12), were only s i g n i f i c a n t l y effected i n one case, that i s , i n the case of Mn. This may p a r t l y be due to the f a c t that the ozone was applied to the leachate before pH adjustment, when, at a c i d i c pH ranges, those elements that have more than one valence state may be expected to be i n the lower state. For example, ir o n at valence 2, has an i o n i c p o t e n t i a l of 2.7 as compared to valence state 3, when the i o n i c p o t e n t i a l i s 4.68. The bounds shown f o r the "Estimated ozone/COD f o r d i s i n f e c t i o n , " i n Figure 15, i s an empiric impositioning of the value found i n these experiments, of the ozone dosage required to k i l l b a c t e r i a . This value f o r b a c t e r i a l k i l l , r e l a t e d as i t i s to the ozone-COD r a t i o , may indicate the mechanism of the often reported "threshold value" or " a l l or nothing" phenomena reported i n the l i t e r a t u r e f o r ozone d i s i n f e c t i o n . Since t h i s concept of ozone-COD r a t i o would be most useful i n determining the q u a ntities of ozone required f o r d i s i n f e c t i o n , the graph, as shown i n Figure 15, i s adequate. Colour and t u r b i d i t y , as noted i n Section 7.3, are both changed and removed by ozone. I t i s possible that an empiric p o s i t i o n f o r both colour and t u r b i d i t y removal could be entered on the Figure 15 graph, so that i t might also predict the ozone required f o r t h i s procedure. 90 7.9 Cost Considerations It i s beyond the scope of t h i s examination to provide a d e t a i l e d cost elaboration f o r t r e a t i n g leachate by physical-chemical systems. I t should be noted, however, that t h i s study indicates the cost f o r d i s i n f e c t i o n , by ozone, i s very s e n s i t i v e to the COD of the wastewater being treated, and that the cost of ozone required w i l l increase, d i r e c t l y , with increasing COD i n the wastewater being treated. T r a d i t i o n a l l y , d i s i n f e c t i o n of water and wastewater has been quantified by overdosing as measured by a r e s i d u a l of the d i s i n f e c t i n g agent i n the treated e f f l u e n t . In the case of wastewaters with r e l a t i v e l y high COD strengths, t h i s may lead to considerable overdosing, beyond the point where d i s i n f e c t i o n has taken place. By using the ozone-COD r a t i o proposed here, to determine the ozone dose required f o r d i s i n f e c t i o n , the overdosing may be prevented. In the case of the leachate under consideration here, with a COD i n the order of 10,000 mg/1, the r a t i o of ozone i n mg/1 to COD i n grams/1 i s approximately 10, but to approach a r a t i o where a r e s i d u a l i s poss i b l e , t h i s r a t i o must be increased by at least 7\ times. When extensive overdosing i s practiced with ozone, i t becomes necessary to equip the ozonation plant with a recycle system to return the unused ozone and c a r r i e r gas to the generation point. This recycle system must be ozone corrosion proof, hence, c o s t l y to i n s t a l l . The c a r r i e r gas, having passed through the wastewater, i s moisture laden and must be dessicated before reentering the ozonator again. This drying of the gas i s , i n most cases, more d i f f i c u l t and more expensive than i s the drying of free a i r from the atmosphere. A l l these considerations lead to higher 91 c a p i t a l costs f o r the ozonating plant-. It has been estimated that i t requires 28 watt-hours of e l e c t r i c a l energy to produce and dose 1000 mg of ozone (32). This f i g u r e includes energy f o r the ozonator and a n c i l l a r y energy f or i n j e c t i o n and a i r preparation. Using t h i s estimate and using an e l e c t r i c a l energy cost of 5 cents per KWH, i t would cost, f o r energy, approximately 10 cents per 1000 gallons f o r d i s i n f e c t i o n . Diaper (32) estimates the cost of amortizing a 10 mgd ozone-dosing plant at 2 times the power costs; there-f o r e , the t o t a l cost f o r d i s i n f e c t i o n of the leachate used i n t h i s project would be i n the order of 30 cents per 1000 gallons f o r that s i z e . For comparison, a plant designed to t r e a t e f f l u e n t from a 10 mgd secondary sewage treatment plant, with an e f f l u e n t COD of 100 to 150 mg/1, would cost approximately 3 cents per 1000 gallons to d i s i n f e c t the e f f l u e n t 92 CHAPTER 8 CONCLUSIONS AND RECOMMENDATIONS 8.1 Conclusions 1. The bulk of the m e t a l l i c pollutant removal was accomplished i n the l i m e - i n i t i a t e d , pH adjustment phase of the treatment. M e t a l l i c ion pollutants with valences of 2 or more were removed by p r e c i p i t a t i o n to l e v e l s adequate to meet regulatory standards (4), but not to l e v e l s indicated by the s o l u b i l i t y products of t h e i r hydroxides. This nonconformity to s o l u b i l i t y - p r o d u c t constants i s probably due to interference by i n t e r i o n i c phenomena i n a strong s o l u t i o n . 2. Soluble organics i n the leachate were not removed s u f f i c i e n t l y by lime pH adjustment to produce an e f f l u e n t that would meet regulatory standards (.4-). "Ozone" organic removals were small and appeared to be d i r e c t l y proportional to the applied ozone dose. 3. Turbidity was increased by lime a d d i t i o n , but ozone i s e f f e c t i v e i n reducing t u r b i d i t y . The e f f e c t i v e elimination of t u r b i d i t y by ozone appears to take place, i n the main part, at comparatively low ozone-COD r a t i o s (5-10 mg/1 ozone per gram/1 COD) with some t a i l i n g of to higher r a t i o s (10-20 mg/1 ozone per gram/1 COD). 4. Leachate colour was reduced by both lime and ozone. There are two sources of colour i n the leachate treated; one from multivalent metals, mainly i r o n , and the other from organic materials. Both lime and ozone caused reduction i n colour caused by metals, while only ozone reduced 93 colour from organics. The organic colour reduction took place at r e l a t i v e l y low ozone doses. 5. Ozone i s an e f f e c t i v e d i s i n f e c t a n t but the d i s i n f e c t i o n process only took place a f t e r the ozone demand of those substances with a greater r e a c t i v i t y with ozone had been s a t i s f i e d . When these substances were measured as COD i n the untreated leachate, the r a t i o of mg/1 of ozone required to grams per l i t r e of COD i n the leachate was 10 to 1. 6. Alum, f e r r i c s u l f a t e and p o l y e l e c t r o l i t e s had no r e a l e f f e c t i n a s s i s t i n g the removal of any pollutants when used i n combination with ozone and lime. These reagents were not tested s i n g l y , so that no judgement i s made of t h e i r singular c a p a b i l i t i e s . 7. Based on the r e s u l t s of t h i s study, f o r the reagents tested and t h i s p a r t i c u l a r leachate, the "best" o v e r a l l treatment would be an a p p l i c a t i o n of 110 mg/1 ozone, followed by pH-adjusted p r e c i p i t a t i o n , using 2350 mg/1 of lime. This would r e s u l t i n : (a) d i s i n f e c t i o n , (b) removal of 97.9 percent of the pretreatment t u r b i d i t y and 90 percent of the colour, (c) removal of 20 percent of the COD, and (d) metals would be removed as l i s t e d : Cu—26%, Fe—99.98%, K—0%, Mn—99.8%, Na—0%, P—98.5%, Pb—39%, Zn—99.9%. The r e s u l t i n g pH would be high, over 10 pH u n i t s . 8.2 Recommendations 1. It i s recommended that a c o n t r o l l e d i n v e s t i g a t i o n of ozone demand be c a r r i e d out, using, i n place of leachate, prepared mixtures of known concentration of soluble metals, organic materials and microbes. 2. Ozone o x i d i z i n g e f f i c i e n c i e s were not investigated i n t h i s 94 project. Other investigators (28) have noted oxidation e f f i c i e n c i e s greater than 100 percent, based on the reduction of COD, u t i l i z i n g one e f f e c t i v e oxygen atom per molecule of ozone. It i s possible that t h i s greater than 100 percent e f f i c i e n c y i s due to short l i f e , single-oxygen, r a d i c a l s formed during the s p l i t t i n g of oxygen molecules i n the e l e c t r i c -discharge, ozone-generating process. These r a d i c a l s have a "forbidden" e l e c t r i c configuration that does not i n v i t e union with an oxygen molecule to form an ozone molecule. The l i f e of t h i s r a d i c a l i s short, i n the order of 100 seconds (33), and the p o s s i b i l i t y of i t becoming a reactant i n a wastewater i s present i f the ozone-oxygen stream i s quickly contacted with the wastewater. An i n v e s t i g a t i o n of t h i s possible phenomenon should be c a r r i e d out by increasing the^time, from generation to reaction through storage, of the newly generated ozone. 3. Additional and more comprehensive studies are necessary before a p r a c t i c a l and economic physical-chemical system can be developed fo r t r e a t i n g raw l a n d f i l l leachate with lime and ozone. These studies should include: a. As i n (1) above b. An i n v e s t i g a t i o n to t r e a t the e f f l u e n t b i o l o g i c a l l y to reduce COD and other parameters to acceptable l e v e l s c. An i n v e s t i g a t i o n to pretreat the raw leachate b i o l o g i c a l l y i n a biosystem or otherwise, to reduce heavy organics and other substances, p r i o r to p h y s i c a l -chemical treatment. 4. Before any other investigations with ozone are c a r r i e d out, the laboratory concerned should have an ozone meter and constant voltage regulators f o r the ozone generator. 95 CHAPTER 9 LIST OF REFERENCES 1. Uloth, V. C. and Mavinic, D. S., "Aerobic B i o s t a b i l i z a t i o n of a High Strength L a n d f i l l Leachate," Faculty of Applied Science Report, University of B r i t i s h Columbia, Page 3, February 1976. 2. - Poorman, B. L., " T r e a t a b i l i t y of Leachate from a Sanitary L a n d f i l l by Anaerobic Digestion," Master of Applied Science Thesis, University of B r i t i s h Columbia, 7 5 pages, A p r i l 1974. 3. Lidkea, T. R. , "Treatment of Sanitary L a n d f i l l Leachate with Peat." M.A.Sc. Thesis, Department of C i v i l Engineering, University of B r i t i s h Columbia, 61 pages, September 1974. 4. P o l l u t i o n Control Board, "Report on P o l l u t i o n Control Objectives f o r Municipal Type Waste Discharges i n B r i t i s h Columbia," Department of Lands, Forests, and Water Resources, Government of the Province of B r i t i s h Columbia, September 1975. 5. Thornton, R. J . and Blanc, F. C. , "Leachate Treatment by Coagulation and P r e c i p i t a t i o n , " Journal of the Environmental Engineering D i v i s i o n , Proc. Amer. Soc. C i v i l Engineers, 99, No. EE4, pp. 535-544, 1973. 6. Chian, E. S. K. and DeWalle, F. B., "Characterization and Treatment of Leachate Generated from L a n d f i l l s , " Water-1974: i i , Municipal Waste  Treatment, AIChE. Symposium Series, 145, V o l . 71, pp. 319-327, 1974. 7. Boyle, W. C. and Ham, R. K., " T r e a t a b i l i t y of Leachate from Sanitary L a n d f i l l s , " Proceedings of the 27th I n d u s t r i a l Waste Conference, May 1972, Part 2, Engineering Extension Series, Purdue Uni v e r s i t y , Purdue, Indiana. 8. 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H., "Some Studies of Ozone f o r Use i n Water Treatment," Proceedings of the Society f o r Water Treatment and Examination, 6, 8, 1957. 97 27. Wynn, C. S., Kirk, B. S. and McNabney, R., " P i l o t Plant f o r T e r t i a r y Treatment of Wastewater with Ozone," Water, A.L.Ch.E. Symposium Series, No. 129, Vol. 69, Page 42, October 1974. 28. Nilson, R., "Removal of Metals by Chemical Treatment of Municipal Waste Water," Water Research, Pergamon Press, Vol. 5, pp. 51-60, Great B r i t a i n , 1971. 29. Netzer, A., Norman, J . D. and Vigers, G. A., "Removal of Trace Metals from Wastewater by Ozonation," Water P o l l u t i o n Research i n Canada 1972, Vol. 7, February 1972. 30. Masterton, W. M. and Slowinski, E. J . , Chemical P r i n c i p l e s , 2nd E d i t i o n , W. B. Saunders Company, Toronto, 1969. 31. Sawyer, C. N. and McCarty, P. L., Chemistry f o r Sanitary Engineers, 2nd E d i t i o n , McGraw-Hill Book Company, Toronto, 1967. 32. Diaper, E. 'W. J . , "Ozone Moves More to the Fore," Water and Wastes Engineering, Page 65, May 1972.' 33. Yates, W. F. and Burleson, J . C , "Chemical Reactions i n a S i l e n t E l e c t r i c Discharge," Chemtech, pp. 31-35, January 1973. 98 CHAPTER 10 - APPENDICES GENERAL BIBLIOGRAPHY 1. Weber, Walter J . , J r . , Physical-Chemical Processes f o r Water Quality- Control, John Wiley and Sons, New York, 1972. 2. Davies, 0. L., Design and Analysis of I n d u s t r i a l Experiments, Hafner Publishing Co., New York, 1954. 3. Netzer, A., Norman, J . D. and Vigers, G. A., "Removal of Trace Metals from Waste Water by Ozonation," Water P o l l u t i o n Research i n Canada 1972, Editor Murphy, K. L. , McMaster Uni v e r s i t y , Ontario. 4. Gabovch, R. D., V r o c h i n s k i i , K. K. and Kurinnyi, I. L., "Decolorization, Deodorization and Decontamination of Drinking Water by Ozonation," Hygiene and Sanitation, Vol. 34, No. 6, pp. 336-340 (English). 5. Posselt, H. S., Reidies, A. H., Weber, W. J . , J r . , "Coagulation of C o l l o i d a l Hydrous Manganese Dioxide," Journal AWWA, p. 50, January 1968. 6. Rebhun, M. S t r e i t , S., "Physico-Chemical Treatment of Strong Municipal Waste Water," Water Research 8_, p. 195, 1974. 7. Linstedt, K. D., Houchk, C. P., O'Connor, J . T. , "Trace Element Removal i n Advanced Waste Water Processes," Journal WPCF, 43, 7, p. 1507, July 1971. 8. 0'Melia, tC. R. , "Coagulation i n Water and Waste Water Treatment," Water Quality Improvement by Physical and Chemical Processes, Edited by Earnest F. Glpyna and W. Wesley Eckenfelder, J r . , University of Texas Press, Austin, Texas, 1965. 9. Stumm, W., 0'Melia, C. R., "Stoichiometry of Coagulation," Journal AWWA, p. 515, May 1968. 10. Weber, W. J . , J r . , Hopkins, C. B., Bloom, R. B., J r . , "Physiochemical Treatment of Waste Water," Journal WPCF 42, 1, p. 83, January 1970. 11. Mackriel, S., "Mechanism of Coagulation i n Water Treatment," Journal Sanitary Engineering D i v i s i o n , Proceedings ASCE, SA3, p. 117, May 1962. 9 9 P H Y S I C A L C H E M I C A L T R E A T M E N T OF L A N D F I L L L E A C H A T E RAW DATA - M g / 1 E X C E P T p H - T U R B I D I T Y AND COLOUR D E P E N D E N T V A R I A B L E S RUN N O . ft >, T) 4-> <U •H X) T3 C CO C CO •H rH O rH Q) id r Q o rd rd •H ft •H U rH -P rH +-> rH CO rH n o O rd o o o o H o H CJ H CO CO co CJ T3 O O 1 2 3 4 5 6 7 8 9 1 0 1 1 1 2 1 3 1 4 1 5 1 6 1 7 1 8 2 0 2 3 R 27 8 . 0 5 8 . 5 0 8 . 4 5 5 . 5 5 7 . 4 0 5 . 6 0 6 . 7 0 9 . 1 1 5 . 0 6 5 . 0 9 6 . 9 3 5 . 5 5 5 . 0 0 5 . 0 0 6 . 1 6 5 . 0 3 6 . 2 0 6 . 8 1 6 . 2 0 6 . 9 5 5 . 9 9 9 5 6 6 4 0 1 2 0 7 8 1 0 0 1 0 4 2 4 7 6 6 0 9 3 5 5 4 5 7 2 1 0 6 6 0 1 8 0 1 5 0 0 4 9 1 5 0 0 2 1 5 1 0 0 0 7 1 2 5 0 0 2 3 0 1 0 0 0 6 4 2 0 6 3 7 4 6 4 8 0 6 4 8 0 6 3 6 0 5 9 7 5 6 6 2 0 6 9 3 2 6 5 4 3 7 2 0 1 6 3 3 0 6 5 5 0 6 7 8 5 7 1 6 0 6 7 9 0 7 3 8 0 3 9 0 0 4 3 0 0 4 0 6 0 4 4 0 0 3 2 2 0 1 5 6 8 0 1 2 5 1 7 1 2 9 2 3 1 1 8 6 4 1 1 9 0 4 1 0 3 5 4 1 2 2 3 8 1 2 7 9 2 1 0 6 7 4 8 8 4 1 1 2 2 0 1 1 0 5 6 0 9 1 4 0 1 0 1 8 8 1 1 8 4 1 8 5 0 3 7 5 7 6 8 9 4 2 7 6 6 9 9 1 3 0 7 5 3 5 7 8 . 7 8 5 6 . 5 6 5 8 6 3 9 1 1 7 5 7 4 3 3 9 1 9 0 6 3 8 1 4 6 3 9 4 5 4 9 2 5 8 . 3 • 1 8 8 0 4 5 2 3 0 9 1 8 3 3 4 3 4 6 5 8 2 6 9 1 1 4 6 2 1 2 7 1 8 9 7 3 4 1 2 5 6 4 1 1 4 5 5 0 . 0 2 9 — 0 . 0 2 9 — 0 . 0 1 8 — 0 . 0 4 2 — 0 . 0 3 0 — 0 . 0 6 4 — 0 . 0 3 5 — 0 . 0 3 1 — 0 . 0 3 9 — 0 . 0 4 1 — 0 . 0 3 7 — 0 . 0 4 1 — 0 . 0 4 2 — 0 . 0 4 8 — 0 . 0 3 9 — 0 . 0 3 5 — : 0 . 0 4 3 ; 0 . 0 4 2 0 . 0 3 6 0 . 0 5 4 0 . 0 4 9 0 . 0 7 0 0 . 0 5 1 0 . 0 6 0 0 . 0 6 5 0 . 0 5 1 0 . 0 5 7 0 . 0 4 0 0 . 0 1 3 0 . 0 5 7 0 . 0 4 1 0 . 0 4 3 0 . 0 3 0 0 . 0 6 4 0 . 0 7 7 0 . 0 4 4 0 . 0 7 3 1 0 0 P H Y S I C A L C H E M I C A L T R E A T M E N T OF L A N D F I L L L E A C H A T E RAW DATA - M g / 1 E X C E P T p H - T U R B I D I T Y AND COLOUR D E P E N D E N T V A R I A B L E S RUN N O . PH c cu rd o rd o o C O M PH S H E-H 0 . 6 2 5 1 2 . 4 7 5 0 . 8 2 1 1 . 4 4 1 6 . 2 0 1 0 . 8 0 7 . 2 8 0 . 3 7 5 1 1 . 7 0 1 6 . 2 0 3 . 9 0 5 . 2 6 1 5 . 0 0 1 6 . 2 0 9 . 6 0 1 5 . 1 0 0 . 1 8 7 . 9 9 3 8 8 0 2 0 . 1 0 . 1 1 6 6 . 6 5 4 2 8 5 1 5 . 0 0 . 1 1 0 8 . 0 0 4 0 4 6 1 4 . 0 0 . 1 7 0 7 . 2 4 4 3 9 6 4 . 0 0 . 1 7 6 8 . 2 0 3 2 1 5 5 . 0 1 2 3 4 5 6 7 8 9 1 0 1 1 1 2 1 3 1 4 1 5 1 6 1 7 1 8 2 0 2 3 R 2 7 4-> •H e c o • H -P o <u +-> CD Q o H m 0 . 1 6 4 0 . 2 1 7 0 . 1 6 4 0 . 1 9 0 0 . 1 8 1 1 . 0 8 1 . 1 7 1 . 0 7 3 8 . 0 3 . 1 3 3 3 . 7 5 1 6 . 5 0 0 . 7 2 3 4 . 2 5 4 0 . 7 5 1 4 . 5 0 3 0 . 2 5 3 3 . 7 5 3 2 . 5 2 5 . 0 0 3 2 . 5 0 4 . 8 0 0 . 3 9 6 . 3 5 0 . 9 0 4 . 7 2 2 1 . 9 1 3 . 5 9 . 4 1 3 7 . 5 3 7 . 5 1 7 5 . 0 1 0 5 . 0 3 . 5 2 5 0 4 4 0 4 3 . 7 5 3 0 0 . 0 4 5 7 47 5 1 6 7 . 5 4 4 1 . 0 1 5 0 1 0 0 3 2 5 5 3 6 0 9 0 0 6 2 5 7 7 5 8 8 0 7 0 0 5 2 5 7 5 0 7 5 2 5 7 5 5 8 0 9 9 0 5 3 7 4 9 0 3 5 0 6 7 5 5 6 0 1 0 2 5 1 1 2 5 1 0 4 0 7 8 0 1 0 2 0 2 5 7 2 4 0 2 4 2 2 4 9 2 4 8 2 4 9 2 5 6 2 4 3 2 5 7 2 7 0 2 2 5 2 4 8 2 6 7 2 6 6 2 4 8 2 7 0 1 4 0 1 5 6 1 3 4 1 6 0 1 5 3 3 6 0 3 3 6 3 3 0 3 5 9 3 4 9 3 5 8 3 5 1 3 2 6 3 5 0 3 6 5 2 7 0 3 5 3 3 6 0 3 7 0 3 5 1 3 7 0 1 5 2 1 5 2 1 5 2 1 5 2 1 5 8 1 0 1 D E P E N D E N T V A R I A B L E S RUN N O . ft Turbidity Colour Total Carbon Total Solids Suspended Solids COD o 3 o 2 9 7 . 2 0 4 5 0 0 4 2 6 0 8 8 3 3 1 4 1 1 9 0 6 — — 0 . 1 0 6 3 0 7 . 2 9 3 2 1 0 0 0 4 1 6 0 9 1 3 5 2 8 1 2 1 9 2 — — 0 . 0 6 9 3 1 6 . 0 9 1 0 0 1 5 0 0 3 8 0 0 7 6 2 4 1 1 1 1 0 9 3 0 — — 0 . 0 6 7 3 2 7 . 2 8 4 5 0 0 3 8 9 0 8 8 5 0 17 1 0 6 0 4 — — 0 . 0 4 7 3 7 6 . 2 0 1 2 5 5 0 0 0 4 2 8 0 8 7 0 7 1 0 6 1 3 5 9 7 — — 0 . 0 8 1 3 8 6 . 9 0 2 4 0 1 5 0 0 4 4 3 0 8 9 4 5 7 6 1 2 8 8 7 — — 0 . 0 5 4 3 9 6 . 0 5 1 6 5 r ' 5 0 0 4 1 8 0 8 5 1 1 9 2 4 1 4 4 0 3 — — 0 . 1 0 0 4 0 5 . 9 5 1 4 5 5 0 0 0 4 2 0 0 8 6 9 4 8 5 2 1 3 4 2 3 — — 0 . 0 9 4 4 1 6 . 4 8 2 1 0 1 0 0 0 3 7 8 0 7 5 1 8 7 4 9 7 0 6 — — 0 . 0 5 1 4 2 6 . 7 2 2 5 0 1 5 0 0 4 3 8 0 8 8 4 3 6 8 1 3 1 9 1 — — 0 . 0 4 1 4 3 6 . 8 5 2 3 5 1 5 0 0 4 5 1 0 9 1 6 8 5 7 1 3 5 3 6 — — 0 . 0 5 5 4 4 8 . 6 0 2 5 2 5 0 4 1 9 0 8 5 6 6 1 4 1 2 5 8 2 — — 0 . 0 4 1 4 5 5 . 9 9 1 9 0 4 0 0 0 4 1 7 0 8 4 5 0 8 2 2 1 3 1 2 3 — — 0 . 0 9 1 4 6 6 . 4 4 1 4 5 1 5 0 0 3 7 0 0 7 3 9 6 1 2 4 1 1 3 9 8 — — 0 . 0 4 6 4 7 6 . 4 5 9 2 1 0 0 0 3 8 0 0 7 5 2 4 2 1 5 1 1 5 6 0 — — 0 . 0 4 6 4 8 6 . 7 0 2 5 5 2 0 0 0 4 3 7 0 8 9 0 3 8 2 1 3 0 5 6 — — 0 . 0 4 1 4 9 8 . 3 5 3 9 2 5 0 4 2 2 0 8 5 1 0 8 1 1 2 1 6 9 — — 0 . 0 6 0 5 0 8 . 2 1 " 6 4 2 5 0 4 2 5 0 8 4 6 1 2 0 1 2 6 5 6 — — 0 . 0 8 5 5 1 6 . 3 9 7 8 1 0 0 0 3 7 0 0 7 0 0 6 5 7 1 1 0 2 5 — — 0 . 1 1 2 5 2 7 . 3 2 6 8 2 5 0 4 1 4 0 8 4 7 8 4 . 1 1 2 1 0 8 — — 0 . 0 4 6 5 3 6 . 8 3 1 8 0 1 0 0 0 3 7 5 0 8 5 3 4 4 . 7 1 1 5 1 1 — — 0 . 0 5 1 5 4 6 . 8 0 2 0 0 1 0 0 0 3 8 1 0 8 4 4 0 4 . 3 1 2 8 2 3 — — 0 . 0 6 3 5 5 6 . 8 1 ' 1 8 0 1 5 0 0 3 7 9 0 8 4 1 6 5 . 1 1 1 7 1 4 0 . 0 6 0 102 D E P E N D E N T V A R I A B L E S RUN N O . c rrj CJ rrj 53 P H o o E-H C J M E-H 29 30 31 32 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 0.164 0.164 0.170 0.213 0.124 0.109 0.128 0.117 0.114 0.057 0.129 0.203 0.116 0.116 0.171 0.131 0.193 0.181 0.121 0.115 0.080 0.139 0.086 0.43 0.45 6.06 0.27 1.15 0.12 3.93 4.71 3.22 0.42 0.13 0.58 2.07 4.61 4.83 0.39 0.05 0.04 3.74 0.06 0.39 0.70 0.315 1.0 8.3 75.5 1.5 250 28.5 50.0 36 150 53 32 0.66 210 165 110 50 4.5 6.5 105 J18 90 80 75 1175 1140 1025 2140 650 1225 1870 1020 985 1175 705 1210 1055 1040 1005 1160 1200 1180 570 1180 1095 1065 2440 158 157 156 140 140 140 142 141 130 140 148 133 134 137 130 143 126 124 114 135 132 126 126 185 160 152 152 140 175 145 255 133 254 145 132 175 140 137 139 147 128 171 135 140 143 160 0.130 0.136 0.190 0.130 0.146 0.160 0.146 0.092 0.130 0.180 0.154 0.160 0.150 0.170 0.41 0.070 0.124 0.130 0.124 0.092 0.108 0.160 0.140 5.85 4.85 8.05 4.60 8.10 5.35 8.20 8.05 7.80 6.20 5.50 1.50 8.05 8.05 7.99 6.25 2.15 2.50 8.05 4.20 6.71 6.80 6.90 4220 4147 3789 3869 4265 4420 4163 4189 3764 4373 4496 4161 4156 3695 3797 4363 4193 4228 3694 4132 3744 3805 3785 40 12.8 10.9 20.8 15.0 9.6 16.5 11.9 16.0 6.5 14 29.2 13.5 5.5 3.0 6.5 2.7 22.0 4.5 7.5 5.6 5.5 5.0 1 0 3 D E P E N D E N T V A R I A B L E S RUN N O . a< Turbidity Colour Total Carbon Total Solids Suspended Solids COD o O 56 8 . 2 0 5 0 5 0 0 3 9 8 0 8 7 1 4 2 . 4 1 1 8 6 0 5 7 1 0 . 2 5 2 . 2 1 6 5 2 7 2 0 9 1 6 9 2 6 1 0 6 8 7 — 5 8 1 0 . 4 0 5 2 : 1 6 5 2 7 0 0 1 2 2 8 4 8 5 1 0 9 8 5 — 5 9 1 1 . 2 27 8 5 2 6 4 0 9 1 8 9 7 6 1 1 1 3 5 — — 6 0 1 1 . 4 4 17 1 6 5 2 6 6 0 9 5 6 9 4 9 1 1 1 5 9 — — 6 1 1 1 . 3 9 2 9 8 5 2 8 2 Q 9 5 2 7 8 3 1 1 2 5 9 — — 6 2 1 0 . 4 2 1 8 1 6 5 2 8 3 0 9 0 4 9 4 . 7 1 0 7 3 7 — — 6 3 1 0 . 2 1 1 9 1 6 5 2 6 6 0 9 0 7 6 3 2 8 3 8 5 — — 6 4 1 0 . 5 0 1 9 1 6 5 2 7 1 0 9 1 5 5 4 2 1 1 1 8 0 — — 6 5 1 0 . 5 1 1 7 2 5 0 2 8 2 0 9 2 2 1 2 2 1 1 1 3 4 — — 6 6 1 0 . 6 1 1 6 2 0 0 2 7 7 0 9 2 3 0 17 1 0 7 3 7 — — 6 7 9 . 7 1 1 6 2 0 0 2 8 2 0 8 7 4 7 2 5 1 1 1 3 5 — — 6 8 9 . 6 0 1 5 2 5 0 . 2 7 4 0 8 8 0 6 1 3 1 0 9 2 8 — — 6 9 9 . 4 1 . ' 1 5 2 0 0 2 8 1 5 8 9 0 3 2 1 1 1 9 1 3 — — 7 0 1 0 . 0 0 1 6 2 0 0 2 8 7 0 9 4 7 1 1 1 1 1 3 9 1 — — 7 1 9 . 2 1 5 2 0 0 2 8 2 0 9 0 2 4 2 0 1 2 1 3 2 — — 7 2 1 0 . 0 0 1 4 2 0 0 2 7 9 0 9 5 7 7 1 5 1 1 1 3 5 — — 7 3 8 . 3 0 2 7 1 7 5 2 5 6 0 6 4 6 5 1 2 9 5 5 3 — — 7 4 9 . 8 3 1 3 1 2 5 2 6 0 0 7 4 4 8 1 8 9 6 9 4 — — 7 5 9 . 9 0 1 4 2 5 0 2 5 9 0 7 3 7 8 1 1 9 0 8 9 — — 76 9 . 5 0 1 6 2 2 5 2 5 5 0 7 4 0 8 8 9 6 5 2 — — 77 8 . 4 0 2 4 5 0 0 2 5 6 0 6 6 9 5 3 9 3 9 5 — — 7 8 1 0 . 1 9 1 6 2 5 0 2 4 9 5 7 5 1 6 2 4 1 0 0 5 8 3 0 . 0 5 5 0 . 0 4 5 0 . 0 3 0 0 . 0 7 5 0 . 0 5 0 0 . 0 5 5 0 . 0 4 5 0 . 0 8 2 0 . 0 6 5 0 . 0 6 9 0 . 0 8 1 0 . 0 6 8 0 . 0 9 4 0 . 0 7 9 0 . 0 9 0 0 . 0 6 7 0 . 0 7 9 0 . 0 7 1 0 . 0 5 6 0 . 0 6 7 0 . 0 6 0 104 D E P E N D E N T V A R I A B L E S RUN N O . XA c IS3 CD rrj O rrj o o O 1—f 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 0.154 0.015 0.020 0.020 0.030 0.025 0.035 0.035 0.025 0.032 6 1195 138 1550 138 1590 138 1670 138 1770 134 1670 134 1560 134 1590 138 1440 138 0.014 0.038 0.427 1615 138 0.019 0.023 0.314 1640 134 0.011 0.026 0.771 1430 142 0.052 0.026 0.328 1490 131 0.052 0.025 0.301 1515 168 0.060 0.207 0.421 1515 172 0.060 0.024 0.543 1410 174 0.057 0.025 0.371 1515 173 0.011 0.0175 3.428 10'50 97 0.011 0.015 0.342 1220 93 0.014 0.018 0.298 1215 99 0.014 0.018 0.285 1230 96 0.018 0.021 3.314 1120 100 0.011 0.016 0.614 1310 100 143 0.180 2.50 3963 17.2 111 0.125 0.09 2719 0.7 111 0.075 0.09 2697 2.7 110 0.086 0.05 2639 0.8 111 0.070 0.05 2659 1.2 111 0.065 0.15 2816 4.2 109 0.081 0.07 2829 0.7 109 0.069 0.07 2655 4.5 111 1:90 0.05 2709 1.4 111 0.055 0.042 2826 4.2 111 0.056 0:036 2768 1.7 111 0.079 0.042 2819 1.4 108 0.067 0.037 2737 2.8 111 0.068 0.036 2809 5.8 111 0.087 0.051 2879 1.24 111 0.079 0.053 2817 3.0 111 0.045 0.044 2788 1.9 82 0.046 0.778 2555 ;4.6 80 0.082 0.171 2599 1.4 84 0.01 0.129 2583 6.5 82 0.10 0.128 2546 4.2 82 0.101 0.721 2544 15.6 83 0.102 0.107 2492 3.3 105 D E P E N D E N T V A R I A B L E S RUN N O . C CO CO • H O H TJ • X) XA O rrj XA rrj •H u H •P U -P H CO H Q O O rrj 0 0 3 O O H O EH O E-i CO CO CO O o o 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 '101 8.21 9.45 10.05 10.00 10.45 10.12 10.59 10.12 10.50 10.20 10.58 10.05 10.40 10.10 10.40 10.10 10.40 10.12 11.52 11.55 11.60 11.60 11.60 23 16 3 32 •9 4 2 3 8 5 4 5 3 4 4 3 9 4 7 33 20 41 6 250 250 600 100 400 100 500 100 400 150 350 100 500 200 550 100 450 100 100 100 100 50 250 2560 2590 3075 3030 2990 2990 3075 2985 2990 2990 3030 2800 2910 2915 3075 2905 2910 3040 2875 2985 2875 2895 2980 6656 7326 7192 7078 7226 7054 7292 7031 7190 7027 7252 7053 7164 6991 7125 6979 7093 6912 7332 7402 7368 7613 6636 5 18 10 46 34 11.0 14 10 38 10 14 26 32 11 14 3 40 5 10 70 38 100 13 9180 9006 8805 8385 8703 8853 8833 8162 8128 8449 8579 8703 9045 8253 8627 8162 8655 8504 8030 8374 8100 8380 8689 — 0.062 — 0.063 — 0.028 — 0.045 — 0.025 — 0.069 — 0.030 — 0.047 — 0.032 — 0.028 — 0.028 — 0.017 — 0.024 — 0.023 — 0.094 — 0.032 — 0.025 — 0.056 — 0.032 — 0.030 — 0.032 -- 0.038 — 0.038 1 0 6 D E P E N D E N T V A R I A B L E S RUN N O . PL, p 0) rd O TO o o H O I—I E-< 7 9 8 0 8 1 8 2 8 3 8 4 8 5 8 6 8 7 8 8 8 9 9 0 9 1 9 2 9 3 9 4 9 5 9 6 9 7 9 8 9 9 1 0 0 * 1 0 1 0 . 0 2 4 0 . 0 1 8 0 . 0 0 7 0 . 0 1 4 0 . 0 1 4 T r T r T r 0 . 0 0 7 T r 0 . 0 0 7 : T r 0 . 0 0 7 0 . 0 0 7 0 . 0 1 4 0 . 0 2 0 0 . 0 1 4 0 . 0 1 4 0 . 0 1 4 0 . 0 1 4 T r 0 . 0 3 6 T r 0 . 0 2 0 0 . 0 1 5 0 . 0 1 4 3 0 . 0 1 2 1 0 . 0 0 2 8 0 . 0 0 5 4 0 . 0 0 6 0 0 . 0 0 2 8 0 . 0 0 2 7 0 . 0 0 4 3 0 . 0 0 6 4 0 . 0 0 4 7 0 . 0 0 2 7 0 . 0 0 9 2 0 . 0 1 2 1 0 . 0 0 5 4 0 . 0 0 9 4 0 . 0 0 2 8 0 . 0 0 2 6 0 . 0 8 3 6 0 . 0 2 3 6 0 . 0 1 3 0 0 . 0 0 6 4 1 . 9 4 2 0 . 8 1 4 1 . 5 7 1 . 9 6 0 . 2 5 0 . 6 6 0 . 3 2 0 . 5 7 0 . 1 9 0 . 6 7 0 . 2 9 2 . 0 0 . 3 0 0 . 5 1 0 . 2 8 0 . 4 8 0 . 1 8 0 . 6 1 0 . 1 1 0 . 8 2 0 . 5 7 1 . 3 0 0 . 8 3 1 0 7 5 1 2 7 0 1 7 1 2 1 7 1 2 1 7 2 5 1 7 1 9 1 7 2 1 1 7 1 4 1 7 7 5 1 5 1 2 1 7 8 8 1 7 2 1 1 7 1 9 1 7 1 2 1 7 2 1 1 6 8 7 1 7 1 2 1 5 7 5 1 9 5 6 1 8 4 4 1 9 0 0 1 7 8 8 1 5 7 5 9 6 8 1 1 0 2 8 5 9 0 7 6 . 2 0 1 0 3 7 6 . 7 5 7 5 . 4 8 9 7 6 8 8 " ' 7 5 . 9 9 0 7 6 . 2 8 8 7 6 . 3 1 0 1 7 5 . 2 8 8 7 5 . 4 1 0 0 7 5 . 2 9 0 7 6 1 0 0 7 6 . 7 9 6 7 5 . 1 9 9 7 6 . 3 8 7 7 5 . 3 9 6 7 5 . 1 5 9 8 7 6 . 7 5 8 6 7 6 . 7 0 8 9 7 7 . 2 9 0 7 6 . 3 9 7 7 7 . 8 0 . 1 1 5 0 . 0 9 5 0 . 2 0 0 . 3 9 0 . 1 7 0 . 1 3 0 . 1 3 0 . 2 2 0 . 1 4 0 . 1 4 0 . 1 5 0 . 1 5 0 . 1 5 0 . 1 4 0 . 1 3 0 . 1 4 0 . 2 1 0 . 1 3 0 . 2 1 0 . 2 8 0 . 2 2 0 . 2 8 0 . 1 6 0 . 1 2 0 . 2 3 6 0 . 2 1 0 . 1 2 0 . 1 8 0 . 1 5 0 . 1 9 0 . 1 0 0 . 1 9 0 . 1 4 0 . 1 0 0 . 1 3 0 . 2 2 0 . 1 3 0 . 1 6 0 . 1 0 0 . 1 6 0 . 1 3 0 . 0 3 0 . 0 3 0 . 0 3 0 . 0 4 0 . 0 4 2 5 4 2 2 5 8 3 3 0 7 3 3 0 2 1 2 9 8 7 2 9 8 6 3 0 7 3 3 9 8 1 2 9 8 8 2 9 8 9 3 0 2 7 2 7 9 9 2 9 0 6 2 9 1 2 3 0 7 1 2 9 0 4 2 9 0 8 3 0 3 9 2 8 7 5 2 9 8 1 2 8 6 6 2 8 8 5 2 9 7 8 1 7 . 9 6 . 8 1 . 7 5 8 . 6 0 3 . 4 0 3 . 6 2 . 1 3 . 6 1 . 7 1 . 4 2 . 8 0 . 9 3 . 6 2 . 8 5 3 . 5 5 1 . 2 1 . 5 0 . 8 4 . 4 8 . 5 9 . 7 5 2 . 2 1 0 7 D E P E N D E N T V A R I A B L E S RUN N O . a Turbidity Colour Total Carbon Total Solids Suspended Solids COD i d o o 3 o 1 0 2 1 1 . 6 3 2 8 1 0 0 3 0 0 5 7 6 6 3 7 3 8 9 3 6 — — 0 . 0 5 4 1 0 3 1 1 . 5 0 1 7 1 0 0 2 9 5 0 7 5 8 5 1 2 8 3 2 3 — — 0 . 0 2 8 1 0 4 1 1 . 5 2 5 1 0 0 3 0 5 0 7 5 8 6 7 8 3 7 8 — — 0 . 0 2 3 1 0 8 D E P E N D E N T V A R I A B L E S RUN N O . -Q u, U rrj O rd P h o o O 1—I EH 1 0 2 1 0 3 1 0 4 0 . 0 4 3 0 . 0 1 2 1 0 . 0 2 0 0 . 0 1 7 1 0 . 0 1 4 0 . 0 0 7 0 0 . 9 6 2 0 3 7 0 . 6 3 1 9 1 2 0 . 1 0 1 8 4 4 9 0 7 6 . 7 5 0 . 1 2 9 9 7 7 . 8 0 . 0 9 8 9 7 7 . 4 0 . 3 4 0 . 0 5 2 9 9 5 0 . 0 3 2 9 4 1 0 . 0 1 3 0 4 4 1 0 . 2 5 9 . 4 6 . 0 

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