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Comparison of raceways of circular and rectangular cross-section for the culture of rainbow trout (salmo.. 1980

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COMPARISON OF RACEWAYS OF CIRCULAR AND RECTANGULAR CROSS-SECTION FOR THE CULTURE OF RAINBOW TROUT (salmo g a i r d n e r i ) by Raul Humberto P i e d r a h i t a B . A.Sc, The U n i v e r s i t y of B r i t i s h Columbia, 1977 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF APPLIED SCIENCE i n THE FACULTY OF GRADUATE STUDIES (Department o f Bio-Resource Engineering) We accept t h i s t h e s i s as conforming to the r e q u i r e d standard THE UNIVERSITY OF BRITISH COLUMBIA • June,1980 0 Raul Humberto P i e d r a h i t a , 19 80 In presenting this thesis in partial fulfilment of the requirements for an advanced degree at the University of Brit ish Columbia, I agree that the Library shall make i t freely available for reference and study. I further agree that permission for extensive copying of this thesis for scholarly purposes may be granted by the Head of my Department or by his representatives. It is understood that copying or publication of this thesis for financial gain shall not be allowed without my written permission. Department nf B i o -Resource E n g i n e e r i n g The University of Brit ish Columbia 2075 Wesbrook Place Vancouver, Canada V6T 1W5 Date August, I98O - i i - ABSTRACT F i s h raceways o f d i f f e r e n t c r o s s - s e c t i o n a l shapes were compared i n b i o l o g i c a l and h y d r a u l i c t e s t s . Raceways of r e c t a n g u l a r and c i r c u l a r c r o s s - s e c t i o n were used. Two types of c i r c u l a r raceways were s t u d i e d , one w i t h a smooth w a l l , made of PVC, and one w i t h a corrugated w a l l , made of g a l v a n i z e d s t e e l t h a t had been p a i n t e d . The b i o l o g i c a l t e s t s c o n s i s t e d of comparing the weight g a i n of rainbow t r o u t (Salmo g a i r d n e r i ) f i n g e r l i n g s ( i n i t i a l weight 6.0 g) h e l d i n the d i f f e r e n t raceways f o r 69 days. The f i s h i n the p a i n t e d c o r r u g a t e d s t e e l raceway ( f i n a l weight 25.6 g) grew more than those i n the r e c t a n g u l a r ( f i n a l weight 22.9 g) and PVC ( f i n a l weight 20.2 g) raceways ( s i g n i f i c a n t at 3 ct = 0.05). Very hi g h s t o c k i n g d e n s i t i e s (130-139 kg/m ) achieved at the end of the experiment. C r i t i c a l c o n c e n t r a t i o n s o f d i s s o l v e d oxygen or ammonia had not been reached a t t h i s p o i n t . Two types o f h y d r a u l i c t e s t s were done. One c o n s i s t e d of flow v i s u a l i z a t i o n s t u d i e s i n which a dye, m a l a c h i t e green, was i n t r o d u c e d i n t o the raceway and i t s movement observed and recorded p h o t o g r a p h i c a l l y . In the second h y d r a u l i c t e s t , the c o n c e n t r a t i o n of m a l a c h i t e green i n the e f f l u e n t was measured at v a r i o u s times a f t e r the i n t r o d u c t i o n o f the dye. These data were then used t o o b t a i n r e s i d e n c e time d i s t r i b u t i o n s f o r the - i i a - v a r i o u s raceways. No major d i f f e r e n c e s were found between the h y d r a u l i c c h a r a c t e r i s t i c s of the raceways t e s t e d . A b i o l o g i c a l t e s t u s i n g unpainted g a l v a n i z e d corrugated s t e e l raceways was a l s o c a r r i e d out. Rainbow t r o u t f i n g e r l i n g s (3.6 g) were p l a c e d i n g a l v a n i z e d raceways t h a t had been f l u s h e d f o r 64 days. The f i s h were l e f t i n the raceways f o r 29 hours. During t h i s time, 48% of the f i s h d i e d . The s u r v i v o r s were t r a n s f e r r e d t o f i b e r g l a s s tanks where an a d d i t i o n a l 27% of the f i s h d i e d over the next 50 hours (2 days). T A B L E OF CONTENTS P a g e ABSTRACT . . . i i T A B L E OF CONTENTS i i i L I S T OF T A B L E S • • • • ' v i i L I S T OF F I G U R E S . • v i i i L I S T OF A P P E N D I C E S X L I S T OF A P P E N D I X - T A B L E S / F I G U R E S . . . . x i ACKNOWLEDGEMENTS x i i 1 . INTRODUCTION 1 2 . L I T E R A T U R E REVIEW 3 2 . 1 I m p o u n d m e n t s U s e d f o r t h e C u l t u r e o f R a i n b o w T r o u t 3 2 . 1 . 1 N a t u r a l p o n d s . 3 2 . 1 . 2 R a c e w a y s 3 2 . 1 . 3 C i r c u l a r i m p o u n d m e n t s 5 2 . 1 . 4 R e c t a n g u l a r c i r c u l a t i n g p o n d s . . 8 2 . 1 . 5 V e r t i c a l u n i t s . 1 0 2 . 1 . 6 C o m p a r i s o n b e t w e e n f l o w t h r o u g h a n d c i r c u l a t i n g p o n d s 12 2 . 2 M o d e l T h e o r y . . 1 4 2 . 3 Z i n c T o x i c i t y t o R a i n b o w T r o u t 17 2 . 3 . 1 E f f e c t o f t e m p e r a t u r e 19 2 . 3 . 2 E f f e c t o f w a t e r h a r d n e s s . . . 20 2 . 3 . 3 E f f e c t o f d i s s o l v e d o x y g e n . . . 2 2 2 . 4 Z i n c R e l e a s e F r o m G a l v a n i z e d M e t a l s . . . 2 2 - i v - THEORY FORMULATION . . .24 3.1 P r o p o s i t i o n s . 24 3.2 A s s u m p t i o n s 25 3.3 I n f e r e n c e s .25 M A T E R I A L S AND METHODS 2 6 4.1 F i s h P e r f o r m a n c e S t u d i e s 26 4.1.1 P h a s e 1 — B e f o r e A u g u s t 15, 1979 ( C o n s t r u c t i o n a n d i n s t a l l a t i o n o f e q u i p m e n t ) 27 4.1.1.1 E q u i p m e n t 27 4.1.1.2 E q u i p m e n t p r e p a r a t i o n a n d t e s t i n g 29 4.1.1.2.1 O r i f i c e c a l i b r a t i o n . • 29 4.1.1.2.2 C o n d i t i o n i n g o f t h e c o r r u g a t e d s t e e l r a c e w a y s 31 4.1.2 P h a s e 2 — A u g u s t 15-16, 1979 ( S t o c k i n g o f t h e r a c e w a y s ) 31 4.1.3 P h a s e 3 — A u g u s t 17- S e p t e m b e r 14, 1979 ( I n t e r m e d i a t e s t a g e , e x p e r i m e n t r e d e s i g n e d ) 33 4.1.4 P h a s e 4 — S e p t e m b e r 14 - N o v e m b e r 22, 197 9 ( C o m p a r i s o n o f t h r e e r a c e w a y s ) . . . 34 4.2 H y d r a u l i c S t u d i e s . 36 4.2.1 F l o w p a t t e r n s 36 4.2.1.1 M a t e r i a l s 36 4.2.1.2 P r o c e d u r e . . . 37 4.2.2 R e s i d e n c e t i m e d i s t r i b u t i o n 38 4.2.2.1 M a t e r i a l s 39 4.2.2.2 P r o c e d u r e 39 - v - 5. RESULTS AND DISCUSSION 42 5.1 Phase 1 — Before August 15, 1979 (C o n s t r u c t i o n and i n s t a l l a t i o n of equipment) 42 5.2 Phase 2 — August 15-16, 1979 (Stocking o f the raceways) 45 5.3 Phase 3 — August 17 - September 14, 1979 (Intermediate stage, experiment redesigned) 48 5.3.1 Water q u a l i t y 51 5.3.2 Observations on the management of the raceways 56 5.4 Phase 4 — September 14 - November 22, 1979 (Comparison of th r e e raceways) . 57 5.4.1 C a r r y i n g c a p a c i t y and l o a d i n g d e n s i t y 6 3 5.4.2 Water q u a l i t y 66 5.4.3 Observations on the management of the system 67 5.5 H y d r a u l i c S t u d i e s 68 5.5.1 Flow p a t t e r n s . . . . . . . . . . . 72 5.5.1.1 A c r y l i c g l a s s p i p e raceway 7 3 5.5.1.2 Rectangular raceway. . . .73 5.5.1.3 Corrugated s t e e l p i p e raceways 78 5.5.2 Residence time d i s t r i b u t i o n s . . . .78 6. CONCLUSIONS 87 - v i - 7 . RECOMMENDATIONS AND SUGGESTIONS FOR FUTURE WORK 89 7 . 1 S u g g e s t i o n s f o r F u t u r e Work 90 L I T E R A T U R E C I T E D 92 A P P E N D I C E S 9 6 - v i i - LIST OF TABLES Table ~ Page \1 Summary of water flow data f o r the v a r i o u s shapes of t r o u t r e a r i n g u n i t s . . . . 6 2 Acute t o x i c i t y (48-, 96-hr L C 5 Q values) of z i n c t o rainbow t r o u t 18 3 Water q u a l i t y d u r i n g Phase 1 43 4 Zin c c o n c e n t r a t i o n i n the g a l v a n i z e d CSP raceways d u r i n g Phase 1 44 5 M o r t a l i t i e s i n the g a l v a n i z e d CSP raceways 4 7 6 Weight, average weight and number of f i s h i n each raceway d u r i n g Phases 2 and 3 5 0 7 Feed, temperature and d i s s o l v e d oxygen d u r i n g Phase 3 52 8 Ammonia and pH d u r i n g Phase 3 -53 9 Weight, average weight and number of f i s h i n each raceway d u r i n g Phase 4 58 10 Feed, temperature and d i s s o l v e d oxygen d u r i n g Phase 4 59 11 Ammonia and pH d u r i n g Phase 4 62 12 C a r r y i n g c a p a c i t y and s t o c k i n g d e n s i t y of the raceways a t v a r i o u s stages of the experiments 64 13 C o n c e n t r a t i o n o f malachyte green i n the e f f l u e n t o f the raceways a t time t a f t e r the i n t r o d u c t i o n of the dye i n the i n f l o w 79 14 Normalized c o n c e n t r a t i o n v a l u e s a t 5 l/min 82 15 Normalized c o n c e n t r a t i o n v a l u e s a t 10 l/min 83 - v i i i - LIST OF FIGURES F i g u r e _ Page 1 T y p i c a l raceway of r e c t a n g u l a r c r o s s - s e c t i o n 4 2 T y p i c a l c i r c u l a r pond 7 3 R e c t a n g u l a r - c i r c u l a t i n g pond 9 4 V e r t i c a l r e a r i n g tank 11 5 T o x i c i t y o f z i n c s u l f a t e t o rainbow t r o u t i n waters of d i f f e r e n t hardness . . . .21 6 P i l o t p l a n t apparatus i n the B i o l o g y B u i l d i n g , U.B.C. 30 7 /Absorbance of malachyte green standards a t 616.9 nm .40 8 S c a l e s on the s u r f a c e of the g a l v a n i z e d CSP raceways • 46 9 F i b e r g l a s s tanks used to h o l d the s u r v i v o r s from the g a l v a n i z e d CSP raceways 4 9 10 Sediment accumulated i n the CSP raceway wi t h the reduced l o a d i n g 69 11 Sediment accumulated i n the PVC raceway w i t h the reduced l o a d i n g 71 12 Flow p a t t e r n s i n the c i r c u l a r raceway at 5 1/min 74 13 Flow p a t t e r n s i n the c i r c u l a r raceway at 10 1/min 75 14 Flow p a t t e r n s i n the r e c t a n g u l a r raceway a t 5 1/min • • • • 76 15 Flow p a t t e r n s i n the r e c t a n g u l a r raceway a t 10 1/min 77 - i x - 16 C o n c e n t r a t i o n o f malachyte green v s . time a t 5 1/min ~. . . 80 17 C o n c e n t r a t i o n of malachyte green v s . time a t 10 1/min 81 18 E - curves a t 5 1/min . 85 19 E - curves a t 10 1/min . .86 - x - L I S T OF APPENDICES A p p e n d i x Page I C o n s t r u c t i o n D e t a i l s o f t h e E q u i p m e n t * • - 9 7 I-A C o r r u g a t e d S t e e l P i p e Raceway 97 I-B PVC Raceway • 99 I-C R e c t a n g u l a r Raceway f o r F i s h T r i a l s - • • -101 I-D A c r y l i c G l a s s P i p e Raceway 103 I-E R e c t a n g u l a r Raceway f o r H y d r a u l i c S t u d i e s 105 I-F S t a n d s f o r t h e Raceways 107 I-G O u t l e t B o x e s 109 I-H C o n s t a n t Head T o w e r s I l l I I D r a w i n g s a n d D i s c h a r g e D a t a f o r O r i f i c e s 113 I I I D a t a S h e e t f o r I n t e r - R a c i n g A n t i f o u l i n g G r e e n P a i n t 116 IV C o m p a r i s o n o f t h e Hach and A u t o - A n a l y z e r M e t h o d s f o r M e a s u r i n g Ammonia- • 117 V P r o c e d u r e f o r M e a s u r i n g Ammonia U s i n g t h e Hach K i t 122 V I P r o c e d u r e f o r M e a s u r i n g Ammonia w i t h t h e A u t o - A n a l y z e r 123 V I I F i l t e r and D e c h l o r i n a t o r U n i t i n t h e B i o l o g y B u i l d i n g , U.B.C. 128 - x i - L I S T OF A P P E N D I X - T A B L E S / F I G U R E S T a b l e P a g e I I - l D i s c h a r g e D a t a f o r O r i f i c e s , D i a m e t e r = 0 . 8 7 c m ; H e a d = 0 . 2 2 m 114 I V - 1 A m m o n i a - N M e a s u r e d w i t h t h e H a c h K i t . a n d t h e T e c h n i c o n A u t o - A n a l y z e r 118 F i g u r e P a g e 1-1 C o r r u g a t e d S t e e l P i p e R a c e w a y . 98 1-2 PVC R a c e w a y . 1 0 0 1 -3 R e c t a n g u l a r R a c e w a y f o r F i s h T r i a l s . . . . . 1 0 2 1-4 A c r y l i c G l a s s P i p e R a c e w a y 104 1 -5 R e c t a n g u l a r R a c e w a y f o r H y d r a u l i c S t u d i e s 106 1 -6 S t a n d s f o r t h e R a c e w a y s . . 1 0 8 1-7 O u t l e t Box . 1 1 0 1 I- 8 C o n s t a n t H e a d T o w e r 112 I I - l O r i f i c e s 115 I V - 1 A u t o - A n a l y z e r v s . H a c h K i t R e a d i n g s o f t h e A m m o n i a - N C o n t e n t o f S a m p l e s • • . . . . . 1 1 9 V I I - 1 F i l t e r a n d D e c h l o r i n a t o r U n i t 129 - x i i - ACKNOWLEDGEMENTS I w i s h t o a c k n o w l e d g e t h e a s s i s t a n c e g i v e n t o me b y t h e members o f my c o m m i t t e e , D r s . R. B u l l e y , T . P o d m o r e a n d J . W . Z a h r a d n i k . I w o u l d a l s o l i k e t o t h a n k t h e t e c h n i c i a n s o f t h e D e p a r t m e n t o f B i o - R e s o u r c e E n g i n e e r i n g , N e i l J a c k s o n , J u r g e n P e h l k e a n d D r . P i n g L i a o f o r t h e i r h e l p a n d a d v i c e i n t h e p r e p a r a t i o n o f t h e e x p e r i m e n t s . S p e c i a l t h a n k s a r e d u e t o M r . B e r n i e Lehman o f S u n V a l l e y T r o u t F a r m s f o r t h e d o n a t i o n o f t h e e x p e r i m e n t a l f i s h . A l s o t o M r . C r a i g W i n t o f W e s t e e l R o s c o f o r t h e d o n a t i o n o f t h e c o r r u g a t e d s t e e l p i p e . L a s t a n d m o s t i m p o r t a n t , I w o u l d l i k e t o t h a n k my w i f e f o r h e r n e v e r - e n d i n g s u p p o r t a n d a d v i c e . 1. INTRODUCTION The search f o r a type of r e a r i n g u n i t i n which t o c u l t u r e rainbow t r o u t (Salmo g a i r d n e r i ) e f f i c i e n t l y has prompted a q u a c u l t u r i s t s t o use a number of b a s i c d e s i g n s . Some of the more common r e a r i n g u n i t s shapes are raceways, c i r c u l a r ponds or tanks, r e c t a n g u l a r c i r c u l a t i n g ponds and v e r t i c a l u n i t s . T h i s c o n t r i b u t i o n t o t h a t s e a r c h c o n s i s t e d o f stu d y i n g raceways of c i r c u l a r c r o s s - s e c t i o n t o determine whether t h e i r h y d r a u l i c c h a r a c t e r i s t i c s would be an improvement over those of c o n v e n t i o n a l raceways of r e c t a n g u l a r c r o s s - s e c t i o n . These h y d r a u l i c c h a r a c t e r i s t i c s c o u l d , i n t u r n , i n c r e a s e the e f f i c i e n c y o f the o p e r a t i o n by improving the space and water u t i l i z a t i o n , r e d u c i n g the maintenance c o s t s ( c l e a n i n g ) , r e d u c i n g the i n s t a l l a t i o n c o s t s , improving the feed u t i l i z a t i o n and r e d u c i n g the i n c i d e n c e of d i s e a s e . Two types o f raceways of c i r c u l a r c r o s s - s e c t i o n were t e s t e d , smooth and corr u g a t e d . The cor r u g a t e d c i r c u l a r c r o s s - s e c t i o n raceways were made from g a l v a n i z e d s t e e l which r e l e a s e s z i n c t h a t has been found t o be t o x i c t o t r o u t under c e r t a i n c o n d i t i o n s ( A f f l e c k , 1952; L l o y d , 1960; L l o y d , 1961; Skidmore, 1964; Herbert and Shurben, 1964; Brown, 1968; Sprague, 1971; S i n l e y e t a l . , 1974). The q u e s t i o n of the z i n c t o x i c i t y was one of t o p i c s i n t h i s i n v e s t i g a t i o n . - 2 - The raceways of c i r c u l a r c r o s s - s e c t i o n were compared t o a c o n v e n t i o n a l raceway of r e c t a n g u l a r c r o s s - s e c t i o n u s i n g 1 :10 h y d r a u l i c models. The experiments were d i v i d e d i n t o two c a t e g o r i e s . One category c o n s i s t e d of comparing the growth r a t e of f i s h h e l d i n the d i f f e r e n t raceways. The ot h e r experiments c o n s i s t e d of comparing the h y d r a u l i c c h a r a c t e r i s t i c s of the d i f f e r e n t raceways by means of h y d r a u l i c t e s t s u s i n g t r a c e r dyes. 3 - 2. LITERATURE REVIEW 2.1 R e a r i n g U n i t s U s e d f o r t h e C u l t u r e o f R a i n b o w T r o u t R e a r i n g u n i t s may be c l a s s i f i e d i n t o f i v e d i s t i n c t - c a t e g o r i e s b a s e d on t h e i r s h a p e . E a c h s h a p e e x h i b i t s some a d v a n t a g e s a n d some d i s a d v a n t a g e s when c o m p a r e d t o t h e o t h e r s . The r e l a t i v e i m p o r t a n c e a s s i g n e d t o t h e v a r i o u s c h a r a c t e r i s t i c s o f t h e c u l t u r e u n i t d e p e n d s on t h e c o n d i t i o n s p r e s e n t a t t h e s i t e f o r w h i c h t h e t r o u t r e a r i n g f a c i l i t y i s b e i n g c o n s i d e r e d . 2.1.1 N a t u r a l p o n d s T h i s c a t e g o r y i n c l u d e s t h o s e e a r t h e n p o n d s o f i r r e g u l a r s h a p e . I n many c a s e s , t h e c o n d i t i o n s i n t h e s e p o n d s a p p r o x i m a t e c l o s e l y t h o s e e n c o u n t e r e d i n n a t u r e (Wheaton, 1 9 7 7 ) . N a t u r a l p o n d s a r e n o t u s e d e x t e n s i v e l y f o r h i g h y i e l d t r o u t p r o d u c t i o n s y s t e m s due t o t h e l a c k o f c o n t r o l o v e r t h e e n v i r o n m e n t o f t h e f i s h , t h e l o w w a t e r u s e e f f i c i e n c y , t h e l o w s t o c k i n g d e n s i t i e s a l l o w e d a n d t h e d i f f i c u l t y o f h a r v e s t i n g t h e f i s h c r o p . 2.1.2 R a c e w a y s . They c o n s i s t o f l o n g , n a r r o w c h a n n e l s ( F i g u r e 1 ) . The i n l e t a n d o u t l e t a r e l o c a t e d a t o p p o s i t e e n d s o f t h e l o n g t 1 111 • +- £k.m £1,20 0.91 F i g u r e 1. T y p i c a l raceway of r e c t a n g u l a r Dimensions i n meters. cr o s s - s e c t i o n . - 5 - channel. The s i z e o f raceways v a r i e s w i d e l y , from 5 m troughs t o over 30 m growout raceways. A t y p i c a l - 3 0 m raceway would be 1.5 to 3 m wide and have a depth of 0.3 to 0.9 m, the c r o s s - s e c t i o n being r e c t a n g u l a r . The bottom of the raceway slo p e s toward the o u t l e t a t l e s s than 1%, u s u a l l y about 0.7% (Burrows and Chenoweth, 1955; Buss and M i l l e r , 1971; Westers and P r a t t , 1977). The most common c o n s t r u c t i o n m a t e r i a l used f o r raceways i s co n c r e t e . Some water flow data r e p o r t e d f o r raceways a r e : average water v e l o c i t y around 0.03 m/s, 1 to 4 exchanges per hour, a c a r r y i n g c a p a c i t y o f 0.4 t o 5 kg/l/min and a s t o c k i n g 3 d e n s i t y o f 16-32 kg/m (Burrows and Chenoweth, 1955; Buss and M i l l e r , 1971; Bardach e t a l . , 1972) (Table 1). The s e t t l i n g of s o l i d s i n the raceways due to the low v e l o c i t y o f flow i s one of the drawbacks of t h i s type of impoundment. I t has been r e p o r t e d (Burrows and Chenoweth, 1955) t h a t the minimum water v e l o c i t y r e q u i r e d t o c a r r y excrement and a l l but the h e a v i e s t d e b r i s i s 0.24 to 0.3 m/s. As the v e l o c i t y decreases, the h e a v i e r p a r t i c l e s s e t t l e u n t i l a t about 0.03 m/s a l l but the most semibuoyant p a r t i c l e s are de p o s i t e d . 2.1.3 C i r c u l a r impoundments (Figure 2) Diameters up t o 13 m have been used. The depth u s u a l l y ranges between 0.6 and 1.2 m and the bottom may be Table 1. Summary o f water flow data f o r the v a r i o u s shapes of t r o u t r e a r i n g u n i t s . Shape C a r r y i n g C a p a c i t y kg/l/min Stocking Density kq/n? Rate of Exchange h r " 1 Raceway (1,2,5) 0.4 - 5 16 - 32 1 - 4 C i r c u l a r (2,6,7,8,9) 1.2 - 2.5 16 - 120 0.5 - 1 i I Rectangular c i r c u l a t i n g (3) 0.6 - 1.2 16 - 32 1.6 V e r t i c a l (4) 1.6 - 1.8 120 - 136 4.5 1. Bardach e t a l . , 1972 2. Burrows and Chenoweth, 1955 3. Burrows and Chenoweth, 1970 4. Buss et a l . , 1970 5. Buss and M i l l e r , 1971 6. K i n c a i d e t a l . , 1972 7. Larmoyeux e t a l . , 197 3 8. Robinson and Varnasoni, 1969 9. Surber, 1936 F i g u r e 2. T y p i c a l c i r c u l a r pond. Dimensions i n meters. - 8 - f l a t or s l o p i n g towards the c e n t r e . The i n l e t i s u s u a l l y a n o z z l e near the s i d e which d i r e c t s the water t a n g e n t i a l l y . The o u t l e t i s some form of standpipe l o c a t e d i n the c e n t r e of the impoundment, or l o c a t e d o u t s i d e and connected to the c e n t r e . The two most common m a t e r i a l s used f o r c i r c u l a r ponds are f i b e r g l a s s and c o n c r e t e . Water flow data f o r c i r c u l a r ponds: 0.5 to 1 exchanges per hour, a c a r r y i n g c a p a c i t y of 1.2 - 2.5 kg/l/min and a s t o c k i n g d e n s i t y of 3 16 - 12 0 kg/m (Surber, 1936; Burrows and Chenoweth, 1955; Robinson and V a r n a s o n i , 1969; Larmoyeux e t al_. , 1973; K i n c a i d e t a l . , 1976) (Table 1). Due to the c i r c u l a r p a t t e r n of the flow, water v e l o c i t i e s i n c i r c u l a r ponds are h i g h e r than those i n raceways (Burrows and Chenoweth, 1955). T h i s p r o v i d e s a b e t t e r sediment c a r r y i n g c a p a c i t y to the water stream which c a r r i e s more s o l i d s out of the pond. 2.1.4 R e c t a n g u l a r - c i r c u l a t i n g pond (Figure 3), a l s o c a l l e d 'Burrows' pond (Burrows and Chenoweth, 1970) U n l i k e the types o f impoundments p r e v i o u s l y c o n s i d e r e d , the r e c t a n g u l a r c i r c u l a t i n g pond was conceived as a containment t h a t would s a t i s f y s p e c i f i c d e s i g n c r i t e r i a . These i n c l u d e d h y d r a u l i c c h a r a c t e r i s t i c s , b i o l o g i c a l c h a r a c t e r i s t i c s of salmonids and f a c t o r s a f f e c t i n g e f f i c i e n t pond o p e r a t i o n . I j J n l t t pipt 1' ' 4 — = = - = = - - 1 r r PtrfortUd scrttn I - v l • - I P 1 1 -* ci L 00 in • .IT h ^ 1 — ii 1 J . 5 -1; ci > 4 22.9 i 2.59 2.59 ^ i £ fc-±-0.15 A f t e r Burrows and Chenoweth, 1970 i F i g u r e 3. Rectangular c i r c u l a t i n g pond. Dimensions.in meters. - 10 - The p ond c o n s i s t s o f a r e c t a n g u l a r c o n c r e t e p o o l 15.3 o r 22.9 m l o n g . T h e r e i s a c e n t r e w a l l p a r t l y d i v i d i n g t h e p o nd i n t o two 2.4 m w i d e s e c t i o n s . The f l o w p a t t e r n i s c o n t r o l l e d by t h e u s e o f a l u m i n u m v e r t i c a l t u r n i n g v a n e s a t e a c h p ond c o r n e r . W a t e r i s i n t r o d u c e d u n d e r p r e s s u r e t h r o u g h two h e a d e r s l o c a t e d a t o p p o s i t e e n d s o f t h e p o o l . W a t e r l e a v e s t h r o u g h two b o t t o m s c r e e n s l o c a t e d n e a r t h e c e n t r e w a l l . W a t e r f l o w d a t a f o r r e c t a n g u l a r c i r c u l a t i n g p o n d s : 1.6 e x c h a n g e s p e r h o u r , c a r r y i n g c a p a c i t y 0.6 - 1.2 k g / l / m i n , s t o c k i n g d e n s i t y 16 - 32 kg/nr 5 ( B u r r o w s a n d C h e n o w e t h , 1970) ( T a b l e 1 ) . The c l e a n i n g e f f i c i e n c y f o r B u r r o w s ' p o n d i s c o m p a r a b l e t o t h a t o f t h e c i r c u l a r p o n d . 2.1.5 V e r t i c a l u n i t s ( F i g u r e 4) The i d e a o f c u l t u r i n g t r o u t i n v e r t i c a l u n i t s o r i g i n a t e d f r o m an e x p e r i m e n t t o s e l e c t f i s h t h a t w o u l d be e x c e p t i o n a l l y t o l e r a n t t o c r o w d i n g ( B u s s e_t a _ l . , 1 9 7 0 ) . The r e s u l t was a n u n a n t i c i p a t e d h i g h r a t e o f s u r v i v a l among t e s t f i s h . The o v e r a l l o b s e r v a t i o n was t h a t w a t e r q u a l i t y was a much more s i g n i f i c a n t f a c t o r i n r e a r i n g r a i n b o w t r o u t t h a n c r o w d i n g . Two s i z e s o f v e r t i c a l u n i t s h a v e b e e n u s e d , one made f r o m 5 5 - g a l l o n (208 1) s t e e l drums a n d t h e o t h e r made f r o m a F i g u r e 4. V e r t i c a l r e a r i n g tank. Dimensions i n meters. - 12 - f i b e r g l a s s tank with a c a p a c i t y of 20.6 m . Water i s i n t r o d u c e d through a pipe d i s c h a r g i n g a g a i n s t the bottom of the tank at i t s c e n t r e . Water e x i t s to a c o l l e c t i n g g u t t e r through a screen l o c a t e d , l i k e a r i n g , around the top of the tank. Water flow data f o r v e r t i c a l u n i t s : 4 t o 5 exchanges per hour, c a r r y i n g c a p a c i t y 1.6 - 1.8 kg/l/min s t o c k i n g 3 d e n s i t y 120 - 136 kg/m (Table 1). There i s no r e p o r t e d data t h a t would allow a comparison of c l e a n i n g e f f i c i e n c y between v e r t i c a l u n i t s and the other types of impoundments. On the other hand, Buss and co-workers (1970) r e p o r t e d the accumulation of some sediment along the bottom edge of the tank and recommended a monthly c l e a n i n g . 2.1.6 Comparison between flow through and c i r c u l a t i n g ponds Of the f i v e types of impoundments mentioned above, three account f o r the g r e a t m a j o r i t y of commercial f a c i l i t i e s i n Canada and the U.S. They are, the raceways, the c i r c u l a r ponds and the r e c t a n g u l a r c i r c u l a t i n g ponds. These can be grouped i n t o two d i s t i n c t types a c c o r d i n g to the way i n which the water flows i n them, the flow-through and the c i r c u l a t i n g types. Raceways belong to the flow-through type. C i r c u l a r and r e c t a n g u l a r c i r c u l a t i n g ponds are c o n s i d e r e d of the c i r c u l a t i n g type (Westers and P r a t t , 1977). - 13 - The b a s i c h y d r a u l i c c h a r a c t e r i s t i c s o f t h e two t y p e s o f p o n d s a r e c o m p l e t e l y d i f f e r e n t . I n t h e c i r c u l a t i n g p o n d , t h e i n c o m i n g w a t e r i s m i x e d w i t h t h e w a t e r i n t h e pond a n d a p p r o x i m a t e l y homogenous w a t e r c o n d i t i o n s r e s u l t . I n c o n t r a s t , t h e f l o w - t h r o u g h p o n d e x h i b i t s a v e r y d i s t i n c t g r a d i e n t i n w a t e r q u a l i t y b e t w e e n t h e i n l e t a n d t h e o u t l e t . I n t h e o r y , a f l o w - t h r o u g h p o n d i s an e x a m p l e o f p l u g f l o w w h i l e t h e f l o w i n a c i r c u l a t i n g pond i s m i x e d ( L e v e n s p i e l , 1 9 7 2 ) . W h i l e some r e s e a r c h e r s ( B u r r o w s and C h e n o w e t h , 1 9 5 5 , 1970; L a r m o y e u x e t a l _ . , 1973) s e e a d v a n t a g e s i n t h e c i r c u l a t i n g t y p e , o t h e r s ( W e s t e r s and P r a t t , 1977) s e e t h e a d v a n t a g e s i n t h e f l o w - t h r o u g h t y p e . The a d v a n t a g e s c l a i m e d f o r t h e c i r c u l a t i n g p o n d s i n c l u d e : a homogeneous e n v i r o n m e n t f o r t h e f i s h , a more e v e n d i s t r i b u t i o n o f f i s h t h r o u g h o u t t h e p o n d , b e t t e r f e e d d i s t r i b u t i o n i n t h e p o n d w i t h c o r r e s p o n d i n g s a v i n g s i n l a b o u r due t o t h e r e d u c e d t i m e r e q u i r e d f o r f e e d i n g , a b e t t e r c l e a n i n g e f f i c i e n c y due t o h i g h e r w a t e r v e l o c i t i e s . I n c o n t r a s t , p r o p o n e n t s o f t h e f l o w - t h r o u g h p ond ( W e s t e r s and P r a t t , 1977) c l a i m t h a t t h e e x i s t e n c e o f a . d i s t i n c t g r a d i e n t i n w a t e r q u a l i t y i s a more d e s i r a b l e c h a r a c t e r i s t i c f o r t h e r e a r i n g e n v i r o n m e n t o f s a l m o n i d s . The r e a s o n b e i n g t h a t i t g i v e s them t h e o p p o r t u n i t y t o s e l e c t t h e h i g h e r w a t e r q u a l i t y , w h i l e i n t h e c i r c u l a t i n g p o n d , t h e f i s h a r e c o n t i n u a l l y e x p o s e d t o an a v e r a g e e n v i r o n m e n t w h i c h c o u l d be m e d i o c r e i n q u a l i t y . A n o t h e r d i s a d v a n t a g e c l a i m e d - 14 - f o r the c i r c u l a t i n g ponds i s t h a t f a s t exchange r a t e s of water are not p o s s i b l e without u p s e t t i n g a w e l l - b a l a n c e d h y d r a u l i c p a t t e r n . T h i s i s p a r t i c u l a r l y important i n view of r e c e n t f i n d i n g s (Buss e t a l . , 1970) which show th a t water q u a l i t y i s a much more s i g n i f i c a n t f a c t o r than crowding i n the r e a r i n g of rainbow t r o u t . Flow-through ponds permit h i g h exchange r a t e s without c r e a t i n g too high v e l o c i t i e s and i n c r e a s e d c o n c e n t r a t i o n s of f i s h may be grown r e q u i r i n g l e s s r e a r i n g space. 2.2 Model Theory In order t o o b t a i n some experimental i n f o r m a t i o n on what the h y d r a u l i c c h a r a c t e r i s t i c s would be i n a p r o d u c t i o n raceway, a model experiment was set up. The f u n c t i o n of a model experiment i s to p r o v i d e d e s i g n data f o r a l a r g e s c a l e i n s t a l l a t i o n (Johnstone and T h r i n g , 1957), or to f a c i l i t a t e the study of the behaviour o f a f u l l s i z e o p e r a t i o n , the pr o t o t y p e . C e r t a i n laws of s i m i l a r i t y must be observed i n order t o i n s u r e t h a t the model-test data can be a p p l i e d t o the prot o t y p e or l a r g e s c a l e . These laws, i n t u r n , p r o v i d e means f o r i n t e r p r e t i n g the t e s t data. The model should be g e o m e t r i c a l l y s i m i l a r t o the prot o t y p e , but t h i s geometric s i m i l a r i t y i s not enough to i n s u r e t h a t the f l u i d motion i n - 15 - the p r o t o t y p e w i l l be a c c u r a t e l y reproduced i n the model. I f the d i r e c t i o n of flow and the r e l a t i v e v e l o c i t i e s are the same i n model and prototype, the flow i s s a i d to be k i n e m a t i c a l l y s i m i l a r . I f both d e n s i t i e s and v e l o c i t i e s are p r o p o r t i o n a l , the model i s s a i d t o be d y n a m i c a l l y s i m i l a r t o the p r o t o t y p e . Complete s i m i l i t u d e r e q u i r e s t h a t a l l of the p r o p e r t i e s of the f l u i d i n the model be r e l a t e d c o r r e c t l y to the corresponding p r o p e r t i e s of the f l u i d i n the p r o t o t y p e . The proper d e n s i t y and v i s c o s i t y of the f l u i d i n the model depend on the geometric s c a l e r a t i o between model and p r o t o t y p e , and on the c h a r a c t e r i s t i c s of the f l u i d i n the p r o t o t y p e . Complete s i m i l a r i t y i s then a p r a c t i c a l i m p o s s i b i l i t y , f o r t u n a t e l y , i t i s not necessary. In any p a r t i c u l a r h y d r a u l i c problem, one law i s u s u a l l y the dominating one and other e f f e c t s may be ignored i f they are s m a l l , o r the r e s u l t s of f o l l o w i n g the major law can be a d j u s t e d to take care of the secondary i n f l u e n c e s . In the case o f flow i n raceways (open channel f l o w ) , the predominant f o r c e s are g r a v i t y and i n e r t i a f o r c e s , g i v i n g r i s e t o the Froude number, F r = v / )J gL where v i s v e l o c i t y , g i s a c c e l e r a t i o n due to g r a v i t y and L i s some c h a r a c t e r i s t i c dimension (Burrows and Chenoweth, 1955; Henderson, 1966; Binder, 1973). H y d r a u l i c models of open channels should be designed such t h a t F r f o r model and p r o t o t y p e are the same. To achieve t h i s , the v e l o c i t y i n - 16 - t h e m o d e l s h o u l d be t o t h e v e l o c i t y i n t h e p r o t o t y p e a s t h e s q u a r e r o o t o f t h e l i n e a r d i m e n s i o n o f t h e m o d e l i s t o t h e s q u a r e r o o t o f t h e l i n e a r d i m e n s i o n o f t h e p r o t o t y p e , i . e . , i n a 1:10 m o d e l , t h e v e l o c i t y s h o u l d be 1/ \ f 10 o r 0.316 t i m e s t h e v e l o c i t y i n t h e p r o t o t y p e . The f l o w , b e i n g t h e p r o d u c t o f v e l o c i t y and area', w o u l d be p r o p o r t i o n a l t o t h e 2.5 power o f t h e l i n e a r d i m e n s i o n r a t i o . The f l o w t h r o u g h a 1:10 m o d e l s h o u l d t h e n be 0.00316 t i m e s t h a t t h r o u g h t h e p r o t o t y p e . I n o p e n - c h a n n e l f l o w , t h e s e c o n d most i m p o r t a n t i n f l u e n c e i s due t o v i s c o s i t y . The r a t i o o f i n e r t i a f o r c e s t o v i s c o u s f o r c e s i s r e p r e s e n t e d b y R e y n o l d s number, Re = pvL/p. w h e r e js i s t h e d e n s i t y o f t h e f l u i d , v i s t h e v e l o c i t y , L a c h a r a c t e r i s t i c d i m e n s i o n a n d p. t h e v i s c o s i t y o f t h e f l u i d . The o n l y p e r f e c t way o f d e a l i n g w i t h t h e e f f e c t o f v i s c o s i t y i s t o k e e p b o t h F r a n d Re t h e same i n m o d e l and i n p r o t o t y p e . T h i s i s a p r a c t i c a l i m p o s s i b i l i t y r e q u i r i n g d i f f e r e n t f l u i d s f o r m o d e l a n d p r o t o t y p e . I f v i s c o s i t y a f f e c t s t h e f l o w p a t t e r n i n t h e p r o t o t y p e , a n y m o d e l s m a l l e r t h a n t h e p r o t o t y p e w i l l h a v e a d i s t o r t e d f l o w p a t t e r n . I f t h e f l o w i n t h e p r o t o t y p e i s f u l l y t u r b u l e n t ( i . e . , a l l v e l o c i t i e s h i g h e nough t h a t v i s c o s i t y i s n o t a f a c t o r ) , t h e r e i s a c r i t i c a l m o d e l s i z e a b o v e w h i c h no a p p r e c i a b l e d i s t o r t i o n o c c u r s a n d b e l o w w h i c h a g r a d u a l l y i n c r e a s i n g d i s t o r t i o n o f - 17 - the flow p a t t e r n r e s u l t s as the model s i z e i s decreased. V e l o c i t i e s i n raceways are low enough t h a t v i s c o s i t y a f f e c t s the flow p a t t e r n . Because of these v i s c o u s e f f e c t s , the flow i s not f u l l y d e f i n e d by geometry throughout the p r o t o t y p e , and there i s no c r i t i c a l model s i z e . The s m a l l e r the model, the g r e a t e r i s the e f f e c t of v i s c o u s drag. 2.3 Zinc T o x i c i t y t o Rainbow Trout A review of the l i t e r a t u r e r e v e a l e d a s m a l l number of r e f e r e n c e s i n which o r i g i n a l r e s e a r c h on the t o x i c i t y of z i n c t o rainbow t r o u t was r e p o r t e d . A f f l e c k (1952) exposed rainbow and brown t r o u t of d i f f e r e n t ages t o water t h a t had passed through g a l v a n i z e d i r o n p i p e s . L a t e r on, o t h e r workers looked a t some of the f a c t o r s t h a t i n f l u e n c e the t o x i c i t y of z i n c t o rainbow t r o u t ( Lloyd, 1960; L l o y d , 1961; Skidmore, 1964; Herbert and Shurben, 1964; Brown, 1968; Sprague, 1971; S i n l e y e t a l . , 1974), i n c l u d i n g the e f f e c t of combining z i n c w i t h other t o x i c substances. The t o x i c c o n c e n t r a t i o n s and some of the c o n d i t i o n s under which they were obtained by the d i f f e r e n t r e s e a r c h e r s are summarized i n T a b l e 2. The recommended s a f e v a l u e f o r continuous exposure i s 1% of the 96 hour LCc>g determined through b i o - a s s a y (U.S.E.P.A., 1976). Using t h i s c r i t e r i o n on the data on Table 2 would y i e l d s a f e c o n c e n t r a t i o n s between 0.001 and 0.008 mg/1. Table 2. Acute t o x i c i t y (48-, 96-hr L C ^ values) of z i n c to rainbow t r o u t . Exposure Time S i z e (hr) Exposure Type Temperature (C) Zinc C o n c e n t r a t i o n (mg/1) pH Hardness mg/1 Reference as CaC0 3 3.9 g 96 FT* 14.8-15.5 0.285 7.3-7. 7 45 (5) 4.9 g 96 FT 14.8-15.5 .0.506 7.3-7. 7 45 (5) 28.4 g 96 FT 14.8-15.5 0.820 7.3-7. 7 45 (5). J u v e n i l e s 96 FT .12.7 0.43 6.8 26 (6) 7.0 g 96 FT 11.6-12.4 0.10 6.8-7. 0 20-25 (2) F i n g e r l i n g s 48 FT 17.7 0.91 6.9 44 (4) 1.5 g 96 s** 10.0 0.09 7.0 20 (3) J u v e n i l e 96 FT 16.2 7.21 7.8 333 (6) 3.9 g 96 FT 14.8-15.5 2.40 7.3-7. 7 100+10 (5) 4. 9 g 96 FT 14.8-15.5 2.66 7.3-7. 7 100+10 (5) 28.4 g 96 FT 14.8-15.5 1.95 7.3-7. 7 100+10 (5) 48 S 15.0 3.20 7.6 300 (1) * FT - Flow-through b i o a s s a y References : (1) Brown, 1968 ** S - S t a t i c ; b i o a s s a y (2) Chapman , 1976 i (3) Garton, 1972 (4) Herbert and Shurben, 1964 (5) Holcombe and Benoit, 1976 (6) S i n l e y et a l . , 1974 - 19 - Chronic t o x i c i t y s t u d i e s done by S i n l e y and co-workers (1974), showed t h a t z i n c c o n c e n t r a t i o n s below 0.036 mg/1 produced no d e t e c t a b l e e f f e c t s on rainbow t r o u t exposed f o r 21 months from the f r y stage to the a d u l t stage. In g e n e r a l , the l i t e r a t u r e i s i n agreement over the f a c t o r s t h a t i n f l u e n c e the t o x i c i t y of z i n c . The d u r a t i o n of exposure i s the most important f a c t o r determining whether a g i v e n c o n c e n t r a t i o n of t o x i c a n t i s s u f f i c i e n t to k i l l a f i s h . T o x i c i t y i s m o d i f i e d by s e v e r a l environmental f a c t o r s p a r t i c u l a r l y temperature, water hardness and d i s s o l v e d oxygen (Skidmore, 1964; U.S.E.P.A., 1976). T o x i c i t y a l s o depends on the l i f e stage a t which the f i s h are f i r s t exposed to the t o x i c a n t and on a c c l i m a t i z a t i o n of the f i s h due to p r e v i o u s exposure t o n o n - l e t h a l c o n c e n t r a t i o n s of the t o x i c substances. 2.3.1 E f f e c t of temperature There has been o n l y one study r e p o r t e d t h a t looked a t the e f f e c t of temperature on t h e t o x i c i t y of z i n c t o rainbow t r o u t . The study (Lloyd, 1960) compared the s u r v i v a l times of rainbow t r o u t i n f o u r c o n c e n t r a t i o n s of z i n c , i n hard water, t e s t e d a t f o u r temperatures. F i s h were t e s t e d a t 13.5, 15.5, 18.5 and 21.5°C. S u r v i v a l times were g e n e r a l l y lower i n the warmer water, but the t h r e s h o l d c o n c e n t r a t i o n appears t o be unchanged. - 20 - 2 . 3 . 2 E f f e c t of water hardness Hardness i s c o n s i d e r e d t o be the most important f a c t o r m o d i f ying the t o x i c i t y of z i n c (Lloyd, 1 9 6 0 ; Skidmore, 1 9 6 4 ; S i n l e y e t a_l. , 1 9 7 4 ) . L l o y d measured the s u r v i v a l time of rainbow t r o u t i n a s e r i e s of c o n c e n t r a t i o n s of z i n c , a t three hardness l e v e l s (Figure 5 ) . He observed t h a t the e f f e c t of hardness i n c r e a s e d w i t h i n c r e a s e i n p e r i o d of s u r v i v a l , u n t i l t h e r e was a t e n - f o l d d i f f e r e n c e between the t o x i c i t i e s o f z i n c i n the hardest ( 3 2 0 mg/1 as CaCO^) and the s o f t e s t ( 1 2 mg/1 as CaCO^) water over 2 . 5 days exposure. S i n l e y and co-workers ( 1 9 7 4 ) looked a t the e f f e c t o f water hardness on the t o x i c i t y o f z i n c t o j u v e n i l e rainbow t r o u t i n an acute t o x i c i t y t e s t ( 9 6 hours) and i n a c h r o n i c t o x i c i t y t e s t ( 2 1 months). The 9 6 hour LĈ Q obt a i n e d f o r j u v e n i l e rainbow t r o u t i n hard ( 3 3 0 mg/1 as CaCO^) and s o f t ( 2 5 mg/1 as C a C 0 3 ) water a t 1 5 C were 7 . 2 1 0 and 0 . 4 3 0 mg/1 r e s p e c t i v e l y . The r e s u l t s of the c h r o n i c t o x i c i t y t e s t s a l s o show t h a t the t o x i c i t y o f z i n c decreases as water hardness i n c r e a s e s . The maximum a c c e p t a b l e t o x i c a n t c o n c e n t r a t i o n (MATC) i n hard water was found t o be between 0 . 6 4 0 mg/1 where there was some z i n c caused m o r t a l i t y and 0 . 3 2 0 mg/1 where th e r e was no z i n c caused m o r t a l i t y . In s o f t water the MATC was found to be, between 0 . 2 6 0 mg/1 and 0 . 1 4 0 mg/1, f o r f i s h exposed t o the z i n c from the egg stage, and between 0 . 0 7 1 and 0 . 0 3 6 mg/1 f o r f i s h f i r s t exposed t o the z i n c a t the f r y stage i . e . , 1 . 5 g. - 21 - 0.5 1 2 5 10 20 CONCENTRATION OF ZINC (P-P.m.Zri) A = t o t a l hardness 320 mg 1 ^ as CaCO, B = t o t a l hardness 50 mg 1 as CaCO C = t o t a l hardness 12 mg 1 as CaCO ( A f t e r L l o y d , 1960) F i g u r e 5. T o x i c i t y o f z i n c s u l f a t e to rainbow t r o u t i n waters o f d i f f e r e n t hardness. - 22 - I t i s b e l i e v e d t h a t the reason f o r the decreased t o x i c i t y o f z i n c i n hard waters i s the a n t a g o n i s t i c a c t i o n between the z-nc i o n s and the i o n s o f the a l k a l i n e - e a r t h metals (Skidmore, 1964). As r e p o r t e d by Skidmore (1964), Jones (1939) e s t a b l i s h e d a d i f f e r e n c e i n the a n t a g o n i s t i c a c t i o n between copper and the v a r i o u s a l k a l i n e - e a r t h metals. Strontium was found t o cause the g r e a t e s t a n t a g o n i s t i c a c t i o n , f o l l o w e d by c a l c i u m , magnesium and barium i n t h a t order. 2.3.3 E f f e c t of d i s s o l v e d oxygen The e f f e c t of d i s s o l v e d oxygen on the t o x i c i t y of z i n c t o rainbow t r o u t has been s t u d i e d by L l o y d (1961). He exposed rainbow t r o u t t o f i v e l e t h a l c o n c e n t r a t i o n s of z i n c s u l f a t e at three n o n - l e t h a l c o n c e n t r a t i o n s of d i s s o l v e d oxygen, i n hard water (320 mg/1 as CaCO^)• He c a l c u l a t e d t h a t , over an exposure p e r i o d of 1000 minutes, the c o n c e n t r a t i o n of z i n c necessary to k i l l h a l f of the f i s h was 1.4 times h i g h e r a t an oxygen c o n c e n t r a t i o n of 8.9 mg/1 than i t was a t 3.8 mg/1. 2.4 Z i n c Release From G a l v a n i z e d M e t a l s G a l v a n i z e d s t e e l sub-merged i n water corrodes r e l e a s i n g z i n c . Many f a c t o r s such as water hardness, pH and - 23 - time o f exposure a f f e c t the r a t e of c o r r o s i o n of the z i n c s u r f a c e . Zinc corrodes f a i r l y r a p i d l y d u r i n g t h e " e a r l y stages o f exposure but c o r r o s i o n slows down q u i c k l y w i t h the f o r m a t i o n o f p r o t e c t i v e f i l m s on the z i n c s u r f a c e . The f i l m s are composed of c o r r o s i o n products l i k e z i n c oxide and z i n c carbonate t h a t are s t r o n g l y adherent and have a low s o l u b i l i t y . The r a t e o f c o r r o s i o n i s lower when the c o n d i t i o n s are f a v o u r a b l e f o r the formation of the f i l m s . Such c o n d i t i o n s a r e : pH i n the range 6.5 to 12, low d i s s o l v e d oxygen and CC>2 i n the water, hi g h water hardness (Zinc Development A s s o c i a t i o n , 1965; Slunder and Boyd, 1971; Pr o s k u r k i n and Gorbunov, 1972; Noyce et a l . , 1975). There are many r e p o r t s a v a i l a b l e on the c o r r o s i o n of z i n c i n n a t u r a l waters but few g i v e q u a n t a t i v e data which can be used. The f i g u r e g i v e n f o r z i n c r e l e a s e i n s o f t 2 2 water i s 25 mg/dm /day and 2.5 mg/dm /day i n hard water (Slunder and Boyd, 1971). I t i s i n t e r e s t i n g to note t h a t water hardness has a double e f f e c t on the use o f g a l v a n i z e d raceways f o r c u l t u r i n g t r o u t . On one hand, water hardness a f f e c t s the r a t e o f z i n c r e l e a s e and hence the z i n c c o n c e n t r a t i o n i n the raceway. The ot h e r e f f e c t of water hardness i s on the t o x i c i t y o f the z i n c t o the f i s h . In both cases, s o f t water aggravates the problem by cau s i n g more z i n c t o be r e l e a s e d and a t the same time making i t more t o x i c t o the f i s h . 3 . THEORY FORMULATION T h e b a s i c t h e o r y s u p p o r t i n g t h i s p r o j e c t h a s b e e n d e v e l o p e d f r o m : 1) A s e t o f p r o p o s i t i o n s w h i c h a r e a l r e a d y known t o b e t r u e . 2) A s e t o f a s s u m p t i o n s w h i c h a r e t e n t a t i v e l y a s s u m e d t o b e t r u e f o r t h e s a k e o f b u i l d i n g t h e t h e o r y . 3) A s e t o f i n f e r e n c e s . 3 . 1 P r o p o s i t i o n s H y d r a u l i c m o d e l s c a n b e u s e d t o s t u d y o p e n c h a n n e l f l o w . T h e c h a r a c t e r i s t i c s o f t h e f l o w i n a r a c e w a y d e p e n d o n t h e s h a p e o f t h e r a c e w a y a n d o n t h e w a t e r f l o w r a t e . T h e s e t t l i n g o f s o l i d s i n a c h a n n e l i s d e p e n d e n t o n t h e c h a r a c t e r i s t i c s o f t h e p a r t i c l e s a n d o n t h e v e l o c i t y a n d t u r b u l e n c e o f t h e w a t e r f l o w i n g i n t h e c h a n n e l . G a l v a n i z e d m a t e r i a l s c o r r o d e a n d r e l e a s e z i n c . T h e r a t e a t w h i c h z i n c i s r e l e a s e d i s d e p e n d e n t o n t h e c h e m i c a l a n d p h y s i c a l c h a r a c t e r i s t i c s o f t h e w a t e r f l o w . T h e t o x i c i t y o f z i n c t o r a i n b o w t r o u t d e p e n d s o n t h e a g e a t w h i c h t h e f i s h a r e f i r s t e x p o s e d t o t h e z i n c a n d o n t h e p h y s i c a l a n d c h e m i c a l c h a r a c t e r i s t i c s o f t h e w a t e r . - 25 - 3 . 2 A s s u m p t i o n s T h e r a t e a t w h i c h z i n c i s r e l e a s e d f r o m t h e w a l l s o f t h e g a l v a n i z e d p i p e c a n be p r e d i c t e d . S a f e c o n c e n t r a t i o n s o f z i n c c a n be e s t a b l i s h e d f o r t r o u t u n d e r c o n t i n u o u s e x p o s u r e . T h e g r o w t h r a t e o f f i s h i s a f f e c t e d b y t h e h y d r a u l i c c h a r a c t e r i s t i c s o f t h e r a c e w a y i n w h i c h t h e y a r e r e a r e d . 3 . 3 I n f e r e n c e s T h e r e i s l e s s s e t t l i n g o f s o l i d s i n a r a c e w a y o f c i r c u l a r c r o s s - s e c t i o n t h a n i n a r a c e w a y o f r e c t a n g u l a r c r o s s - s e c t i o n i f b o t h r a c e w a y s h a v e t h e same c r o s s - s e c t i o n a l a r e a a n d t h e same a v e r a g e v e l o c i t y . F i s h g r o w f a s t e r i n a r a c e w a y o f c i r c u l a r c r o s s - s e c t i o n . I t i s s a f e t o u s e g a l v a n i z e d p i p e r a c e w a y s f o r r e a r i n g t r o u t u n d e r c e r t a i n c o n d i t i o n s . 4. MATERIALS AND METHODS From o b s e r v a t i o n s of f i s h r e a r i n g f a c i l i t i e s and from work done by o t h e r r e s e a r c h e r s (Burrows and Chenoweth, 1955) i t has become r e a d i l y apparent t h a t a very s t r o n g c o r r e l a t i o n e x i s t s between the performance of f i s h and the h y d r a u l i c c h a r a c t e r i s t i c s of the environment i n which the f i s h l i v e . Because t h i s c o r r e l a t i o n i s not f u l l y understood and because f a c t o r s other than h y d r a u l i c i n f l u e n c e the performance of the f i s h , i t was decided to separate the experimental work i n t o two d i s t i n c t areas of concern. One area had t o do w i t h the study of the h y d r a u l i c c h a r a c t e r i s t i c s of the raceways under c o n s i d e r a t i o n , the other w i t h the performance of f i s h r e a r e d i n d i f f e r e n t types of raceways. A d e t a i l e d review of the two areas of r e s e a r c h f o l l o w s . 4.1 F i s h Performance S t u d i e s In order to make the d e s c r i p t i o n of the experiments c l e a r e r t o the reader, i t w i l l be presented i n f o u r phases t h a t f o l l o w a c h r o n o l o g i c a l o r d e r : Phase 1, b e f o r e August 15, 1979 ( C o n s t r u c t i o n and i n s t a l l a t i o n of equipment). Phase 2, August 15-16, 1979 (Stocking of the raceways). Phase 3, August 17 to September 14, 1979 (Intermediate stage, - 27 - experiment r e d e s i g n e d ) . Phase 4, September 14 to November 22, 1979 (Comparison o f three raceways). 4.1.1 Phase 1. — Before August 15, 1979 ( C o n s t r u c t i o n and i n s t a l l a t i o n of equipment) The work done i n t h i s phase c o n s i s t e d of the p r e p a r a t i o n of the s i t e , the c o n s t r u c t i o n and i n s t a l l a t i o n of the raceways and the performance of p r e l i m i n a r y water a n a l y s e s . 4.1.1.1 Equipment The s i z e s o f t e s t raceways were determined by the a p p l i c a t i o n of model theory. The pr o t o t y p e or l a r g e s c a l e r e c t a n g u l a r raceway i s a h y p o t h e t i c a l raceway of the f o l l o w i n g dimensions: l e n g t h 24.4 m, width 2.4 m, depth 0.91 m, bottom s l o p e 0.5%. A s c a l e r a t i o o f 1:10 was s e l e c t e d f o r the model r e c t a n g u l a r raceway as the most p r a c t i c a l f o r these s t u d i e s . The s i z e s of the raceways of c i r c u l a r c r o s s - s e c t i o n were chosen so they would have the same l e n g t h and c r o s s - s e c t i o n a l area as the model r e c t a n g u l a r raceway. The dimensions of the 1:10 model of the r e c t a n g u l a r raceway a r e : l e n g t h 2.44 m, width 0.24 m, depth 0.09 m and slope 0.5%. The raceways of c i r c u l a r c r o s s - s e c t i o n are of the same l e n g t h as the r e c t a n g u l a r model, namely 2.4 m. - 28 - l The diameters of the p i p e s used and the depth to which they were f i l l e d were chosen such t h a t the c r o s s - s e c t i o n a l area are approximately equal t o t h a t of the r e c t a n g u l a r raceway. 2 The c r o s s - s e c t i o n a l area o f the r e c t a n g u l a r model i s 0.022 m . A pipe o f 0.20 m diameter would have to be f i l l e d t o 0.78 times the diameter ( i . e . 0.16 m) and a p i p e of 0.25 m diameter would be f i l l e d t o 0.41 times the diameter ( i . e . 0.10 m). For the i n i t i a l f i s h t r i a l s , two Corrugated S t e e l Pipe (CSP) raceways of 0.20 m diameter (Appendix I-A) and two PVC raceways of 0.20 m diameter (Appendix I-B) were used (Figure 6). The c o n c e n t r a t i o n of z i n c i n the CSP raceways can be p r e d i c t e d based on the f i g u r e s g i v e n f o r the r a t e of z i n c r e l e a s e i n s o f t water ( S e c t i o n 2.4). In s o f t water, z i n c 2 i s r e l e a s e d a t the r a t e of 25 mg/dm /day (Slunder and Boyd, 1971). With a flow o f 5 l/min through the CSP raceway, the expected average z i n c c o n c e n t r a t i o n i n the e f f l u e n t would be 0.380 mg/1. I f a supply of hard water were a v a i l a b l e , the z i n c c o n c e n t r a t i o n would be reduced t o 0.038 mg/1. I t i s u n f o r t u n a t e t h a t a supply of hard water c o u l d not be found and a l l the experiments had to be c a r r i e d out i n very s o f t water, 5 mg/1 as CaCO^ as determined by the EDTA t i t r i m e t r i c method (American P u b l i c H e a l t h A s s o c i a t i o n , 1976). The f o u r raceways used i n the f i r s t s e c t i o n of the experiments, two PVC and two CSP, r e c e i v e d the water from two constant head towers (Appendix I-H), through o r i f i c e s - 29 - (Appendix I I ) ( F i g u r e 6). A constant flow r a t e was maintained t o the raceways. The water e x i t e d the raceways through a p e r f o r a t e d p i p e i n s e r t e d through the end cap of the raceway (Appendix I-G). The p e r f o r a t e d pipe was connected t o a standpipe (Appendix I-G) f o r the c o n t r o l of the water l e v e l i n the raceway. The raceways were p l a c e d on stands (Appendix I-F) . 4.1.1.2 Equipment p r e p a r a t i o n and t e s t i n g 4.1.1.2.1 O r i f i c e c a l i b r a t i o n . C a l c u l a t i o n s t o determine the diameter o f the o r i f i c e r e q u i r e d t o o b t a i n the d e s i r e d d i s c h a r g e were made from the equation 2 Q = c W 4 d — ( 2 g H ) 1 / 2 (Binder, 1973) where d i s the o r i f i c e diameter, c i s a constant f o r the o r i f i c e , g i s the g r a v i t a t i o n a l a c c e l e r a t i o n , H i s the head and Q i s the d i s c h a r g e . I n i t i a l c a l c u l a t i o n s f o r o r i f i c e s i z e were made w i t h an assumed con s t a n t c. The o r i f i c e s were then d r i l l e d and c a l i b r a t e d . The necessary adjustments i n o r i f i c e diameter were made i n order t o s a t i s f y the flow requirements. A l l o r i f i c e s were c a l i b r a t e d and the data i s presented i n Appendix I I . - 30 - F i g u r e 6. P i l o t P l a n t A p p a r a t u s i n t h e B i o l o g y B u i l d i n g , U.B.C. - 31 - 4.1.1.2.2 C o n d i t i o n i n g of the corrugated s t e e l raceways. A f t e r c o n s t r u c t i o n and t e s t i n g f o r l e a k s , the raceways were f l u s h e d with tap water f o r a p e r i o d of 26 days a t a flow r a t e of approximately 13 l/min per raceway. The water temperature was 10°C. During t h i s time, 40 0 ml water samples were taken on days 3 and 16 from the e f f l u e n t , a c i d i f i e d w i t h 1.5 ml/1 n i t r i c a c i d (70% HNO^) and analyzed f o r z i n c u s i n g a J a r r e l Ash ( D i v i s i o n of F i s h e r S c i e n t i f i c ) , Model 8 00 atomic a b s o r p t i o n spectrophotometer. Due t o the very low c o n c e n t r a t i o n s of z i n c p r esent, i t was necessary i n some cases t o c o n c e n t r a t e the a c i d i f i e d sample by e v a p o r a t i o n without b o i l i n g (American P u b l i c H e a l t h A s s o c i a t i o n , 1976). A f t e r f l u s h i n g , the raceways were t r a n s f e r r e d to the c o u r t y a r d of the B i o l o g y B u i l d i n g on campus, where a supply of d e c h l o r i n a t e d c i t y water i s a v a i l a b l e (Appendix V I I ) . The raceways were i n s t a l l e d as shown i n F i g u r e 6. They were then f l u s h e d f o r a p e r i o d of 30 days w i t h a flow of 5 l/min per raceway. Samples were agai n c o l l e c t e d and analyzed f o r z i n c on days 40 and 64 from the i n i t i a t i o n o f the f l u s h i n g . At the end of the 30 day f l u s h i n g p e r i o d , the f i s h were stocked. 4.1.2 Phase 2 — August 15-16, 1979 (Stocking o f the raceways) The purpose of t h i s s e c t i o n of the experiments was to determine whether the amount of z i n c r e l e a s e d from the w a l l s - 32 - of the g a l v a n i z e d CSP raceways was enough to cause heavy m o r t a l i t i e s t o the t r o u t . On August 15, 1979, rainbow t r o u t f i n g e r l i n g s (average weight 3.65 g) were secured from Sun V a l l e y T r o u t Farms i n M i s s i o n , B.C. The f i s h were t r a n s p o r t e d i n buckets w i t h oxygen b e i n g bubbled throughout the t r i p . Upon a r r i v a l , the f i s h were weighed and d i s t r i b u t e d e q u a l l y i n the four raceways. The weighing was done wi t h a Toledo model 4030 balance with a c a p a c i t y o f 5 kg. A f o u r l i t r e bucket was f i l l e d w i t h approximately two l i t r e s o f water and i t s weight was recorded. Some f i s h were then n e t t e d and p l a c e d i n the bucket c o n t a i n i n g the weighed water. The new weight of the bucket was recorded and the weight of the f i s h was determined by s u b t r a c t i n g the i n i t i a l bucket weight. Consecutive batches o f f i s h weighed i n t h i s f a s h i o n were p l a c e d i n d i f f e r e n t raceways. The average weight of the f i s h was determined by weighing a sample o f 100 f i s h . The number of f i s h was c a l c u l a t e d from the t o t a l weight and the average weight. Unexpectedly h i g h m o r t a l i t i e s o f the f i s h i n the g a l v a n i z e d CSP raceways prompted the t e r m i n a t i o n of t h i s phase of the experiment d u r i n g the second day (Aug. 16, 1979). The s u r v i v i n g f i s h from the g a l v a n i z e d raceways were t r a n s f e r r e d to two f i b e r g l a s s tanks. - 33 - 4 . 1 . 3 Phase 3 — August 17 t o September 1 4 , 1979 (Intermediate stage, experiment redesigned) The t h i r d phase of the experiment c o n s t i t u t e d an i n t e r m e d i a t e stage i n which p r e p a r a t i o n s were made f o r conducting a redesigned experiment i n the f o u r t h phase. During t h i s time, the f i s h were h e l d i n two PVC raceways and two f i b e r g l a s s tanks. The f i s h were fed an amount e q u i v a l e n t t o 3% of t h e i r body weight per day d i s t r i b u t e d i n t hree f e e d i n g s , a c c o r d i n g t o the recommendations of the feed manufacturers. The feed used was Ewos number 2 Salmon S t a r t e r , manufactured by R i t c h i e - S m i t h L t d . of A b b o t s f o r d , B.C. In p r e p a r a t i o n f o r the f o u r t h phase, a r e c t a n g u l a r c r o s s - s e c t i o n raceway was b u i l t . C o n s t r u c t i o n d e t a i l s are presented i n Appendix I-C. The r e c t a n g u l a r and the g a l v a n i z e d CSP raceways were both p a i n t e d w i t h green i n t e r - r a c i n g a n t i - f o u l i n g p a i n t manufactured by I n t e r n a t i o n a l P a i n t s (Appendix I I I ) . The s u r f a c e of the g a l v a n i z e d CSP raceway was prepared by a p p l y i n g a coat of z i n c chromate primer. The a n t i f o u l i n g p a i n t c o n t a i n s copper and some apprehension e x i s t e d as to the p o s s i b l e t o x i c i t y t o the t r o u t . Lovegrove (1979) r e p o r t e d the use of a s i m i l a r p a i n t i n rainbow t r o u t tanks. He found t h a t the copper c o n c e n t r a t i o n i n the tank water dropped v e r y q u i c k l y from 9 J i g /1 two hours a f t e r f l o o d i n g the tanks t o 2 ^ag/1 e i g h t e e n days a f t e r f l o o d i n g . The E.P.A. minimum r i s k - 34 - l e v e l i s 10 jug/1 (U.S.E.P.A., 1976). In our case, the p a i n t e d raceways were f l u s h e d f o r s i x days a t 5 1/min b e f o r e three f i s h were i n t r o d u c e d i n each. The f i s h were observed f o r 10 days. No d e l e t e r i o u s e f f e c t s were observed and the raceways were stocked. 4.1.4 Phase 4 — September 14 - November 22, 1979 (Comparison of t h r e e raceways) During the f o u r t h phase of the experiments, the performance of the f i s h h e l d i n three types of raceways was compared. The raceways were: a PVC p i p e raceway, a p a i n t e d g a l v a n i z e d CSP raceway and a wooden, r e c t a n g u l a r c r o s s - s e c t i o n raceway. On September 14, the f i s h from the two PVC raceways were weighed and d i v i d e d i n t o t h r e e groups of equal weight. The f i s h from the f i b e r g l a s s tank were a l s o weighed and d i v i d e d i n t hree groups. One group from each of the two s e t s was p l a c e d i n t o each of the t h r e e raceways used i n the f o u r t h phase. The f i s h were fed t h r e e times a day. The amount of feed was a d j u s t e d based on the i n c r e a s i n g f i s h weight and the changing water temperature, f o l l o w i n g the manufacturers recommendations. Water samples from each of the raceways and from the supply were c o l l e c t e d p r i o r t o f e e d i n g . The d i s s o l v e d oxygen - 35 - and temperature were measured a t the s i t e , immediately a f t e r c o l l e c t i o n . /Ammonia and pH were measured i n the l a b o r a t o r y w i t h i n one hour of c o l l e c t i n g the samples. The procedures used were: a. D i s s o l v e d oxygen. I t i s recommended t h a t the e f f l u e n t have a d i s s o l v e d oxygen not lower than 5 mg/1 (Willoughby, 1968; Buss and M i l l e r , 1971; Westers and P r a t t , 1977). A membrane e l e c t r o d e was used t o measure the d i s s o l v e d oxygen w i t h a model 54, Yellow Springs Instruments d i s s o l v e d oxygen meter. The instrument was c a l i b r a t e d f o l l o w i n g the procedure i n d i c a t e d i n the manual f o r the apparatus. b. Temperature. The temperature was measured u s i n g a thermocouple i n c o r p o r a t e d i n the d i s s o l v e d oxygen e l e c t r o d e and checked a g a i n s t a mercury thermometer a t l e a s t once every two weeks. c. pH. Measured w i t h a F i s h e r Accumet Model 420 D i g i t a l pH/ion meter. d. Ammonia. Measured by the N e s s l e r method u s i n g a Hach DR-EL/2 D i r e c t Reading Engineer's L a b o r a t o r y K i t (Hach Chemical Co., Ames, Iowa). The Hach method was c a l i b r a t e d a g a i n s t i n d u s t r i a l method No. 154-71W f o r ammonia i n water and seawater u t i l i z i n g a Technicon Auto A n a l y z e r I I (Technicon I n d u s t r i a l Systems, Tarrytown, N.Y.)(Appendices IV, V and V I ) . A c a l i b r a t i o n equation was o b t a i n e d (Appendix IV). The v a l u e s f o r ammonia pre s e n t e d throughout t h i s t h e s i s were obtained by use of the c a l i b r a t i o n e q u a t i o n . - 36 - 4 . 2 H y d r a u l i c S t u d i e s T h e r e a s o n f o r d o i n g h y d r a u l i c t e s t s o f t h e r a c e w a y s was t o o b t a i n a c h a r a c t e r i z a t i o n o f t h e f l o w w i t h o u t f i s h . S u p e r i m p o s e d o n t h i s u n d i s t u r b e d f l o w a r e t h e t u r b u l e n c e s g e n e r a t e d b y t h e f i s h i n a l o a d e d r a c e w a y . Two t e s t s w e r e d o n e o n e a c h r a c e w a y , o n e p r o v i d e d q u a l i t a t i v e i n f o r m a t i o n i n t h e f o r m o f o b s e r v a t i o n o f t h e movemen t o f a t r a c e r w i t h i n t h e r a c e w a y . The s e c o n d t e s t p r o d u c e d some q u a n t i t a t i v e i n f o r m a t i o n a s r e s i d e n c e t i m e d i s t r i b u t i o n s . 4 . 2 . 1 F l o w p a t t e r n s T h e s t u d y o f f l o w p a t t e r n s p r o v i d e s q u a l i t a t i v e i n f o r m a t i o n o n t h e way i n w h i c h t h e w a t e r m o v e s t h r o u g h t h e r a c e w a y . I t m a k e s p o s s i b l e t h e i d e n t i f i c a t i o n o f a r e a s o f s l o w m o v i n g w a t e r a s w e l l a s a r e a s o f h i g h v e l o c i t y . T h e f l o w p a t t e r n s w e r e made v i s i b l e b y t h e i n t r o d u c t i o n o f a d y e i n t o t h e i n c o m i n g s t r e a m o f w a t e r . 4 . 2 . 1 . 1 M a t e r i a l s T h e s t u d y o f f l o w p a t t e r n s r e q u i r e s t h a t t h e r a c e w a y s h a v e t r a n s p a r e n t w a l l s . B e c a u s e o f t h i s , o n l y two r a c e w a y s o - 37 w e r e s t u d i e d . One r a c e w a y . w a s o f r e c t a n g u l a r c r o s s - s e c t i o n w i t h s i d e s made o f c l e a r a c r y l i c g l a s s 2 . 4 m l o n g , 0 . 2 4 m w i d e a n d was f i l l e d t o a d e p t h o f 0 . 0 9 m ( A p p e n d i x I - E ) . The o t h e r r a c e w a y t e s t e d was made f r o m a 0 . 2 0 m d i a m e t e r a c r y l i c g l a s s p i p e f i l l e d t o 0 . 8 t i m e s t h e d i a m e t e r o r 0 . 1 6 m. The l e n g t h o f t h i s r a c e w a y w a s 2 . 4 m ( A p p e n d i x I - D ) . The f l o w t o t h e r a c e w a y s was r e g u l a t e d u s i n g a c a l i b r a t e d o r i f i c e u n d e r a c o n s t a n t h e a d . 4 . 2 . 1 . 2 P r o c e d u r e Two f l o w r a t e s w e r e u s e d i n t h e t e s t s , 5 . 0 a n d 1 0 . 0 l / m i n . T h e y w e r e d e t e r m i n e d u s i n g F r o u d e ' s n u m b e r , b a s e d o n w h a t a r e c o n s i d e r e d t y p i c a l f l o w s f o r t h e p r o t o t y p e r a c e w a y . T h e r e c o m m e n d e d f l o w f o r t h e p r o t o t y p e r a c e w a y i s b e t w e e n 900 a n d 3600 l / m i n c o r r e s p o n d i n g t o o n e a n d f o u r e x c h a n g e s p e r h o u r ( B u r r o w s a n d C h e n o w e t h , 1 9 5 5 ; B u s s a n d M i l l e r , 1 9 7 1 ) . U s i n g a c o n s t a n t F r o u d e number a s t h e c r i t e r i o n f o r t h e s c a l i n g o f t h e f l o w r a t e , t h e r e q u i r e d f l o w f o r t h e m o d e l c a n b e f o u n d t o b e b e t w e e n 2 . 9 a n d 1 1 . 6 l / m i n . The f l o w r a t e s u s e d i n t h e t e s t s , 5 . 0 a n d 1 0 . 0 l / m i n a r e w i t h i n t h e r a n g e r e q u i r e d . T h e s e f l o w r a t e s c o r r e s p o n d t o 1 . 7 5 a n d 3 . 5 0 e x c h a n g e s p e r h o u r i n t h e p r o t o t y p e . T h e f l o w p a t t e r n s w e r e made v i s i b l e b y t h e i n t r o d u c t i o n o f a d y e , m a l a c h y t e g r e e n , i n t o t h e i n c o m i n g s t r e a m o f w a t e r . - 38 - The m a l a c h y t e g r e e n c r y s t a l s w e r e d i l u t e d i n d i s t i l l e d w a t e r t o make a 10 g/1 s t o c k s o l u t i o n . The amount o f d y e u s e d d i f f e r e d f o r t h e two f l o w r a t e s . A t 5.0 1/min, 10 m l o f s t o c k s o l u t i o n w e r e u s e d . A t 10 1/min, 20 m l w e r e u s e d . The d y e was i n j e c t e d w i t h a p i p e t t e i n t o t h e i n c o m i n g s t r e a m o f w a t e r a s t h e s t r e a m h i t t h e w a t e r s u r f a c e i n t h e r a c e w a y . The d u r a t i o n o f t h e d y e i n j e c t i o n was a p p r o x i m a t e l y 10 s e c o n d s i n a l l c a s e s . The movement o f t h e d y e a l o n g t h e r a c e w a y was r e c o r d e d on b l a c k a n d w h i t e f i l m (Kodak t r i - x p a n ) . A r e d f i l t e r ( V i v i t a r 25A) was p l a c e d i n f r o n t o f t h e c a m e r a t o i m p r o v e t h e c l a r i t y o f t h e i m p r e s s i o n on t h e b l a c k a n d w h i t e f i l m . The p h o t o g r a p h s w e r e t a k e n a t v a r i o u s t i m e s a f t e r t h e i n t r o d u c t i o n o f t h e d y e . 4.2.2 R e s i d e n c e t i m e d i s t r i b u t i o n The s t u d y o f r e s i d e n c e t i m e d i s t r i b u t i o n s p r o v i d e s i n f o r m a t i o n on t h e b e h a v i o u r o f a f l u i d i n a c o n t a i n e r by l o o k i n g o n l y a t i t s i n p u t s a n d o u t p u t s . R e s i d e n c e t i m e d i s t r i b u t i o n d a t a may p o i n t o u t t h e p r e s e n c e o f s h o r t c i r c u i t i n g s t r e a m s o r d e a d a r e a s i n a r a c e w a y , b u t i t d o e s n o t p r o v i d e an i n d i c a t i o n a s t o w h e r e i n t h e r a c e w a y t h e s e a r e . - 39 - 4.2.2.1 M a t e r i a l s In a d d i t i o n t o the raceways used i n the flow p a t t e r n s t u d i e s , two more were t e s t e d f o r t h e i r r e s i d e n c e time d i s - t r i b u t i o n . One was made from 0.25 m (10 i n , nominal s i z e ) diameter CSP and i t was f i l l e d t o 0.4 times the diameter. The other was made from 0.20 m (8 i n , nominal s i z e ) diameter CSP and i t was f i l l e d t o 0.8 times the depth. Both raceways were 2.4 m long (Appendix I ) . 4.2.2.2 Procedure The procedure c o n s i s t e d i n i n t r o d u c i n g the dye f o r a p e r i o d o f 10 seconds i n t o the i n f l o w and then c o l l e c t i n g samples from the e f f l u e n t t o determine the c o n c e n t r a t i o n o f dye l e a v i n g the raceway w i t h time (Burrows and Chenoweth, 1955; L e v e n s p i e l , 1972). The t r a c e r and the procedure f o r i n t r o d u c i n g i t i n t o the raceways were s i m i l a r t o those used i n the flow p a t t e r n s t u d i e s . Samples from the e f f l u e n t were c o l l e c t e d a t predetermined time i n t e r v a l s . The samples were then analyzed u s i n g a H i t a c h i Perkin-Elmer 139 UV-VIS.spectrophotometer t o determine the c o n c e n t r a t i o n of malachyte green p r e s e n t . Absorbance was measured a t 616.9 nm, the wave l e n g t h of peak absorbance f o r malachyte green (Stecher, 1968). The c o n c e n t r a t i o n was then determined by r e f e r e n c e t o a c a l i b r a t i o n run i n the spectrophotometer (Figure 7 ) .  - 41 - The c o n c e n t r a t i o n s thus obtained were normalized by d i v i d i n g them by the area under the c o n c e n t r a t i o n versus time curve. When the normalized v a l u e s are p l o t t e d a g a i n s t time, the E-curves are ob t a i n e d ( L e v e n s p i e l , 1972). The area under the E-curves i s u n i t y . The f o u r raceways were each t e s t e d a t two flow r a t e s , 5.0 and 10.0 1/min. - 42 - 5. RESULTS AND DISCUSSION 5.1 Phase 1 — Before August 15, 1979 ( C o n s t r u c t i o n and i n s t a l l a t i o n of equipment) During the p r e p a r a t i o n p e r i o d , the data c o l l e c t e d c o n s i s t e d of water q u a l i t y parameters such as: temperature, d i s s o l v e d oxygen, pH, hardness and z i n c . Temperature: At the s t a r t of the f l u s h i n g p e r i o d , the water temperature was 10°C. By the end of the f l u s h i n g , the temperature had r i s e n t o 13°C (Table 3). Both temperatures are s u i t a b l e f o r the c u l t u r e of rainbow t r o u t . D i s s o l v e d oxygen: The v a l u e s f l u c t u a t e d from a low of 7.7 mg/1 (68% s a t u r a t i o n at 10°C) t o a h i g h of 10.0 mg/1 (88% s a t u r a t i o n a t 10°C)(Table 3). pH: The water presented a s l i g h t l y a c i d i c pH, f l u c t u a t i n g between 6.2 and 6.5 (Table 3). Water hardness: A very low v a l u e f o r the water hardness was found. Three measurements were made p r i o r t o the i n t r o d u c t i o n of the f i s h . The a n alyses were done a t one week i n t e r v a l s . The v a l u e s o b t a i n e d were 5.0, 4.5 and 5.5 mg/1 as CaC0 3- Z i n c : The v a l u e s obtained f o r the z i n c c o n c e n t r a t i o n are presented i n T a b l e 4. I t i s i n t e r e s t i n g t o note t h a t the expected decay i n r a t e of r e l e a s e (Slunder Table 3. Water q u a l i t y d u r i n g Phase 1. Day Number Date Temperature (°C) D.O. (mg/1) pH 33 J u l y 19/79 10 8.0 40 J u l y 20/79 10 7.7 6.2 44 J u l y 24/79 10 10.0 45 J u l y 25/79 9.5 10.0 6.5 50 J u l y 30/79 11 9.4 64 Aug. 13/79 13 9.2 6.3 Water hardness 5 mg/1 as CaCO-. Table 4. Zinc c o n c e n t r a t i o n i n the g a l v a n i z e d CSP raceways d u r i n g Phase 1. Zinc C o n c e n t r a t i o n (mg/1) Day Number Date Raceway 1 Raceway 2 3 June 13/79 0.43 0.12 16 June 26/79 0.02 0.16 40 J u l y 20/79 0.16 0.05 i 64 Aug. 13/79 0.23 0.24 , - 45 - and Boyd, 1971) d i d not occur. The reason f o r t h i s i s thought t o have been the removal-of some of the p r o t e c t i v e f i l m t h a t had formed on the g a l v a n i z e d p i pe The removal may have come about when the sediment and some s c a l e s t h a t had formed on the z i n c s u r f a c e (Figure 8) were removed by g e n t l e s c r a p i n g w i t h the bare hand i n p r e p a r a t i o n f o r the i n t r o d u c t i o n of the f i s h . The z i n c c o n c e n t r a t i o n i n the raceways was measured one day b e f o r e s t o c k i n g the f i s h and found t o be 0.23 and 0.24 mg/1 f o r each of the two CSP raceways. 5.2 Phase 2 — August 15-16, 1979 (Stocking o f the raceways) The u n s u i t a b i l i t y of the environment i n the g a l v a n i z e d raceways was demonstrated by the heavy m o r t a l i t i e s s u s t a i n e d . The f i r s t deaths o c c u r r e d between f o u r and ei g h t e e n hours a f t e r the f i s h were i n t r o d u c e d i n the raceways (Table 5). The f i s h continued t o d i e even a f t e r having been t r a n s f e r r e d from the g a l v a n i z e d raceways t o f i b e r g l a s s tanks. The z i n c c o n c e n t r a t i o n s at the time the f i s h were brought i n were 0.24 and 0.23 mg/1 (Table 4) f o r the two raceways. The r e p o r t e d s a f e v a l u e s range from 0.038 t o 0.260 mg/1 f o r s o f t water, w i t h 96 hour L C ^ ' s i n the range 0.100 to 0.820 mg/1 (Se c t i o n 2.3). I t i s thought t h a t the unexpectedly h i g h m o r t a l i t i e s were due t o the extremely unfavourable water con- d i t i o n s , s p e c i f i c a l l y the ve r y low water hardness, 5 mgA as CaCO-j. F i g u r e 8. S c a l e s on the s u r f a c e of the g a l v a n i z e d CSP raceways. Table 5. M o r t a l i t i e s i n the g a l v a n i z e d CSP raceways. Time Time No. of Dead F i s h Avg.Death Rate/hour No.of F i s h Remaining A f t e r S t o cking I n t e r v a l Raceway 1 Raceway 2 Raceway 1 Raceway 2 Raceway 1 Raceway 2 (hr) (hr) 3.5* 3.5 0 0 18. 5 15. 0 59 51 24. 5 6.0 46 48 29.0** 4.5 42 71 42.5 13 . 5 121 141 48.0 5.5 19 10 53. 0 5.0 21 10 66. 5 13. 5 10 7 72.0 5.5 2 1 80.5 8.5 0 2 0 0 438 438 3.9 3.4 379 387 7.7 8.0 333 339 9.3 15.8 291 268 9.0 10.4 170 127 3.5 1 .8 151 117 4.2 2.0 130 107 0.7 0.5 120 100 0.4 0.2 118 99 0 0.2 118 97 * Time 0 i s a t 13:25, August 15/80. ** The s u r v i v o r s were t r a n s f e r r e d to f i b e r g l a s s tanks a t 29.0 h r s . - 48 - 5.3 Phase 3 — August 17 - September 14, 197 9 (Intermediate stage, experiment redesigned) During t h i s p e r i o d , August 17 to September 14, 1979, f i s h were h e l d i n two PVC raceways and the s u r v i v o r s from the g a l v a n i z e d pipe raceways were h e l d i n two f i b e r g l a s s tanks (Figure 9) u n t i l August 29 when they were counted and put i n one f i b e r g l a s s tank o n l y . Table 6 shows the t o t a l weight, average weight and number of f i s h i n each raceway f o r t h i s p e r i o d . Note t h a t some of the v a l u e s are measured and o t h e r s c a l c u l a t e d . The t o t a l weights were measured by the procedure o u t l i n e d i n S e c t i o n 4.1.2. The average weights were determined by c o u n t i n g two 50 f i s h batches and weighing them. The number o f f i s h was found by d i v i d i n g the t o t a l weight by the average weight, except f o r m o r t a l i t i e s and s u r v i v o r s i n the f i b e r g l a s s tank t h a t were counted. At the end of t h i s p e r i o d , i t was found t h a t f i s h i n the raceway PVC 2 had grown more than those i n the raceway PVC 1 which i n t u r n had grown more than those i n the f i b e r g l a s s tank. The average weights were found to be 6.4, 5.8 and 5.5 g r e s p e c t i v e l y . When a 10% e r r o r estimate i s taken i n t o account, these weights become 6.4 + 0.6, 5.8 + 0.6, and 5.5 + 0.6. The e r r o r o r i g i n a t e s i n the weighing t e c h n i q u e s . Every time a f i s h i s n e t t e d and p l a c e d i n the weighing bucket, an undetermined amount of water i s i n t r o d u c e d . The amount of water would be d i r e c t l y r e l a t e d to the number F i g u r e 9. F i b e r g l a s s tanks used to h o l d the s u r v i v o r s from CSP raceways. Table 6. Weight, average weight and number of fish in each raceway during Phases 2 and 3. Weight of Fish Avg. Weight of Fish Estimated No.of Fish Mortalities for (g) (g/fish) Aug.15/79 to Aug.15/79 Sept.15/79 Aug.15/79 Sept.15/79 Aug.15/79 Sept.15/79 Sept.15/79 (No.of Fish) PVC Raceway 1 1612 2524 3.65* 5.8** 442*** 434*** 8 PVC Raceway 2 1606 2795 3.65* 6.4** 440*** 437*** Combined 3196 920 3.65* 5.5** 876*** 168*** 678 CSP Raceways Total: 6414 6239 3.65* 6.0 1758 1039 689 * *** Calculated from a sample of 100 f i s h at Sun Valley Trout Farms Calculated from two samples of 50 fish each Number of f i s h = (Weight)/(Average Weight). i - 51 - of n e t t i n g s f o r a batch and a l s o depends on the technique of the weigher i . e . , the l e n g t h of time between c a t c h and r e l e a s e i n the bucket, the amount of shaking t a k i n g p l a c e d u r i n g the t r a n s f e r . O v e r a l l , the f i s h grew from an average weight of 3.6 + 0.4 to 6.0 +0.6 g i n the 30-day p e r i o d . 5.3.1 Water q u a l i t y The water q u a l i t y data f o r the p e r i o d i s presented i n Tables 7 and 8. Temperature: No d i f f e r e n c e i n temperature was d e t e c t e d between the i n f l o w and the e f f l u e n t . The temperature ranged from a h i g h of 16°C t o a low of 13°C. Temperatures were measured a t d i f f e r e n t times of the day and no d a i l y f l u c t u a t i o n s were noted. D i s s o l v e d oxygen: The D.O. of the supply f l u c t u a t e d q u i t e c o n s i d e r a b l y from a high of 9.4 to a low of 7.4 mg/1 (Table 7 ). I t i s thought t h a t these v a r i a t i o n s are r e l a t e d t o the management of the f i l t e r i n g system f o r the water supply (Appendix V I I ) . The d i s s o l v e d oxygen i n the e f f l u e n t from the raceways f l u c t u a t e d w i d e l y , f o l l o w i n g the supply f l u c t u a t i o n s i n a d d i t i o n t o day-to-day v a r i a t i o n s of i t s own. ( - 52 - Table 7. Feed, temperature and d i s s o l v e d oxygen d u r i n g Phase 3. Feed/ ~ _ m D i s s o l v e d Oxygen (mg/1) Raceway Temp. " ^' Day No. Date (g) (°c) Supply PVC-1 PVC-2 1 August 15 48 2 16 48 14 9.4 7.5 7.4 3 17 48 14 8.5 7.3 7.0 4 18 48 5 19 48 15 8.2 6.7 7.2 6 20 52 15 8.2 6.9 6.7 7 21 60 15 8.2 6.9 7.0 8 22 56 15 8.4 7.3 6.8 9 23 56 15 8.0 6.9 7.1 10 24 52 16 8.1 6.5 7.1 11 25 48 15 8.3 6.5 7.0 12 26 48 14 8.2 7.0 7.2 13 27 48 14 28 48 14 8.3 7.0 6.9 15 29 48 16 30 48 13 9.4 6.8 7.2 17 31 48 15 8.2 6.5 7.0 18 Sept. 1 32 19 2 36 16 8.3 7.0 7.0 20 3 60 21 4 60 22 5 60 15 8.0 6.1 5.5 23 6 60 15 • 7.9 5.7 5.8 24 7 60 15 7.5 5.7 5.7 25 8 60 26 9 40 27 10 64 28 11 64 29 12 60 14 7.4 5.5 6.0 30 13 60 13 7.9 6.3 6.7 31 14 40 13 8.1 6.4 6.5 Table 8. /Ammonia and pH du r i n g Phase 3. Day No. Ammonia-N (mg/1) Supply PVC-1 PVC-2 Supply PH PVC-1 PVC-2 6.6 6.4 6.4 7 9 0.04 0.13+0.05* 0.08+0.05 0.04 0.08+0.05 0.08+0.05 6.6 6.5 6.5 6.6 6.5 6.5 14 17 0.04 0.08+0.05 0.08+0.05 0.04 0.26+0.07 0.22+0.06 6.4 6.6 6.5 6.5 6.4 6.5 u> 22 27 0.04 0.17+0.05 0.17+0.05 0.04 0.13+0.05 0.13+0.05 6.2 6.2 6.1 6.1 6.1 6.1 * E r r o r a s s o c i a t e d w i t h the experimental procedure (See Appendix I V ) . - 54 - The d i s s o l v e d oxygen d e p l e t i o n i n the raceways i n c r e a s e d from around 1.3 mg/1 i n the i n i t i a l days to a h i g h of 2.1 mg/1 around day 2 3 (September 6, 1979). A s l i g h t d e c l i n e i n oxygen use o c c u r r e d towards the end o f the 30-day p e r i o d . The f i n a l oxygen d e p l e t i o n was down to 1.6. T h i s d e c l i n e c o u l d be due to the drop i n water temperature from 15 to 13 C. D i s s o l v e d oxygen measurements i n the e f f l u e n t were always done p r i o r t o f e e d i n g the f i s h . pH: Both the supply and the e f f l u e n t pH's decreased over the d u r a t i o n of the experiment. The i n i t i a l supply pH was 6.6 on day 2, w h i l e the f i n a l r e a d i n g was 6.2 on day 27 (Table 8). The e f f l u e n t pH was s l i g h t l y (0.1 to 0.2 u n i t s ) lower than the i n f l o w except f o r two cases where the e f f l u e n t pH was 0.1 u n i t s h i g h e r than the supply. In a l l cases, the pH was low enough to i n s u r e t h a t the amount o f ammonia i n the raceways d i d not p r e s e n t a t h r e a t to the f i s h (Lloyd, 1961; Warren, 1962; T r u s s e l l , 1972, U.S.E.P.A., 1976). Ammonia: T o t a l ammonia (NH^ p l u s NH^+) was very low i n a l l cases. The h i g h e s t c o n c e n t r a t i o n recorded was 0.26+0.07 mg/1 Ammonia-N (Table 8). Compare t h i s to the t o t a l ammonia-N c o n c e n t r a t i o n of 21.0 - 55 - mg/1, the v a l u e c o n s i d e r e d t o x i c t o the f i s h a t a pH of 6.5 a t 10°C (Warren, 1962; T r u s s e l l , 1972; Westers and P r a t t , 1977). Although the autoanalyzer i s a d m i t t e d l y more ac c u r a t e than the Hach (Boyd, 197 7), p r a c t i c a l c o n s i d e r a t i o n s prompted the d e c i s i o n t o use the Hach k i t f o r the ammonia analyses i n these experiments. The Hach k i t had the advantage o f being i n e x p e n s i v e t o run and even a s m a l l number of samples c o u l d be analyzed as soon as they were c o l l e c t e d . The r e s u l t s c o u l d then be used t o make management d e c i s i o n s r e g a r d i n g the flow, f e e d i n g l e v e l and f i s h d e n s i t y i n the raceways ( H a s k e l l , 1955; Willoughby, 1968; Boyd, 1977; Westers and P r a t t , 1977). \ 0 - 56 - 5 . 3 . 2 O b s e r v a t i o n s o n t h e m a n a g e m e n t o f t h e r a c e w a y s I n a l l t h e r a c e w a y s , t h e i n f l o w was d i r e c t e d f r o m t h e o r i f i c e b y a f l e x i b l e h o s e . T h e h o s e p r e v e n t e d t h e i n t e r f e r e n c e o f t h e w i n d w i t h t h e i n c o m i n g w a t e r s t r e a m . T h i s h o s e s h o u l d b e s e c u r e l y t i e d down t o p r e v e n t t h e a c c i d e n t a l d i s r u p t i o n o f t h e w a t e r f l o w t o t h e r a c e w a y s . The f l e x i b l e h o s e s h o u l d b e p l a c e d a s c l o s e t o t h e h e a d e n d o f t h e r a c e w a y a s p o s s i b l e t o p r e v e n t t h e o c c u r r e n c e o f b a c k f l o w s . T h e o u t l e t b o x c o l l e c t e d s o l i d s t h a t h a d t o be s i p h o n e d o u t a t l e a s t o n c e a w e e k . The p e r f o r a t e d p i p e t h a t e x t e n d e d i n t o t h e r a c e w a y h a d t o b e c l e a n e d b y i n t r o d u c i n g a t u b e t h r o u g h i t t o s i p h o n o u t t h e m a t e r i a l a c c u m u l a t e d " . The p i p e d e l i v e r i n g t h e e f f l u e n t f r o m t h e o u t l e t b o x t o t h e d r a i n h a d t o be c l e a n e d o u t a t l e a s t o n c e p e r m o n t h b y i n t r o d u c i n g a w i r e t h r o u g h i t . The r a c e w a y s w e r e f o u n d t o b e s e l f - c l e a n i n g . No s o l i d s a c c u m u l a t e d i n t h e r a c e w a y s s t o c k e d w i t h f i s h . T h e r a c e w a y s w e r e c o v e r e d w i t h n e t s ( F i g u r e 6 ) . On s e v e r a l o c c a s i o n s , f i s h j u m p e d o u t o f some o f t h e r a c e w a y s d u e t o s m a l l m a l a d j u s t m e n t s i n t h e p l a c i n g o f t h e n e t t i n g . A f t e r a p p r o x i m a t e l y t w o w e e k s o f b e i n g s t o c k e d , a l g a e s t a r t e d g r o w i n g o n t h e PVC r a c e w a y s . A t t h e e n d o f P h a s e 3 t h e r a c e w a y w a l l s w e r e c o v e r e d b y a g r e e n s l i m y l a y e r t h a t h a d t o b e c l e a n e d b y h a n d . - 57, - 5.4 Phase 4 — September 14 - November 22, 1979 (Comparison of th r e e raceways) In the p e r i o d from September 15 t o November 22, 1979 (69 days), f i s h were held i n t h r e e raceways, one made from PVC, one made from p a i n t e d CSP and one made from wood (Appendix I ) . I n i t i a l l y a l l raceways were loaded w i t h approximately 2080 g each (Table 9 ), or 346 f i s h at 6.0 g each. The flow through each of the raceways was 5 1/min. The f i s h were f e d three times per day f o r a t o t a l of 60 g per raceway per day i n i t i a l l y . T h i s amount was i n c r e a s e d t o 90 g per day by October 22 (day 38)(Table 10). The water q u a l i t y parameters monitored were: temperature, d i s s o l v e d oxygen, pH and ammonia (Tables 10 and 11). F i s h growth: The f i s h weight data i s presented i n Table 9. I n i t i a l l y , each raceway h e l d approximately 2080 g o f f i s h o r 346 f i s h at an average weight o f 6.0 g. During the f i r s t day i n the new raceways, 26 f i s h jumped out of the cor r u g a t e d s t e e l raceway due to a p o o r l y p o s i t i o n e d net. Other than these, the t o t a l m o r t a l i t i e s f o r the p e r i o d were s i x . The f i n a l average weights were determined by cou n t i n g and weighing f o u r samples of 20 f i s h from each o f the raceways. The v a l u e s i n d i c a t e a h i g h e r growth r a t e f o r the f i s h i n the CSP raceway (25.6 g / f i s h ) , f o l l o w e d by the f i s h i n the r e c t a n g u l a r raceway (22.9 g / f i s h ) and by the f i s h i n the PVC raceway (20.2 g / f i s h ) . ( s i g n i f i c a n t l y d i f f e r e n t at oC = 0.05, by Duncan's m u l t i p l e range t e s t (Walpole and Myers, 1972)). Table 9. Weight, average weight and number of fish in each raceway during Phase 4. Weight of Fish Avg.Weight of Fish Estimated No.of Fish Mortalities for (g) (g/fish) September 15/79 Sept.15/79 Nov.22/79 Sept.15/79 Nov.22/79 Sept.15/79 Nov.22/79 to Nov.22/79 (No.of Fish) PVC Raceway 2080 7505 6.0* 20.2** 346 371 2 Rectangular 2072 7521 6.0* 22.9** 345 328 3 Raceway CSP Raceway 2087 7034 6.0* 25.6** 348 275 27 Total: 6239 22060 6.0* 22.7 1039 974 32 * ** *** See Table 6. Calculated from two samples of 50 fish each. Number of fi s h = (Weight)/(Average Weight). - 59 - Table 10. Feed, temperature and dissolved oxygen during Phase 4. Feed/ Raceway. Temp. Dissolved Oxygen (mg/1) Day No. Date (g) (°C) Supply PVC RECT CSP 1 Sept. 15 40 13 7.8 6.4 6.3 6.6 2 16 60 3 17 60 11 7.8 6.7 7.6 6.6 4 18 40 11 7.3 6.1 6.7 6.7 5 19 60 6 20 60 7 21 60 8 22 60 9 23 45 10 24 60 14 8.0 6.8 6.7 6.6 11 25 60 12 26 60 14 7.6 5.9 6.1 6.0 13 27 60 14 28 60 14 7.9 6.1 6.6 6.1 15 29 60 16 30 60 15 17 Oct. 1 60 14 7.4 5.7 6.0 5.8 18 2 60 19 3 66 14 8.3 6.4 6.0 6.2 20 4 72 21 5 72 22 6 48 23 7 72 24 8 72 13 8.2 6.6 6.3 6.3 25 9 48 26 10 72 27 11 72 28 12 72 14 8.5 5.9 6.1 6.1 29 13 72 30 14 48 i - 60 - Table 10. (Cont'd) Feed/ Raceway Day No. Date (g) 31 Oct. 15 72 32 16 72 33 17 50 34 18 75 35 19 75 36 20 75 37 21 60 38 22 90 39 23 90 40 24 90 41 25 90 42 26 90 43 27 90 44 28 60 45 29 90 46 30 90 47 31 90 48 Nov. 1 90 49 2 90 50 3 90 51 4 60 52 5 90 53 6 90 54 •7 90 55 8 90 56 9 90 57 10 90 58 11 60 59 12 85 60 13 90 Temp. Dissolved Oxygen (mg/1) (°C) Supply PVC " RECT CSP 14 8.0 6.7 6.2 7.0 12 8.1 6.1 6.1 5.8 12 9.8 6.5 6.1 6.3 12 11.0 6.1 7.0 7.3 11 11.0 7.7 7.7 8.1 10 10 11.0 7.9 6.5 8.1 10 10 11.0 8.6 7.8 8.0 10 11.1 7.6 7.5 7.6 10 9 9 9 11.1 7.7 7.5 7.3 - 61 - Table 10. (Cont'd) Feed/ Raceway Temp. Dissolved Oxygen (mg/1) Day No. Date (g) (°C) Supply PVC RECT CSP 61 Nov. 14 90 9 62 15 90 63 16 90 64 17 90 9 11.2 7.8 7.9 8.0 65 18 45 66 19 90 8 11.4 7.7 8.0 7.6 67 20 90 68 21 90 8 11.5 8.1 8.0 7.3 69 22 90 Table 11. Ammonia and pH during Phase 4. Ammonia-N (mg/1) pH Day No. Date Supply PVC RECT CSP Supply PVC RECT CSP 9 Sept. 23 0.08+0.05* 0. 17+0.05 0.22+0.06 0.17+0.05 6.2 6.0 5.9 6.1 31 Oct. 15 < 0.04 0. 13+0.05 0.08+0.05 0.13+0.05 6.4 6.2 6.2 6.2 46 Oct.. 30 0.08+0.05 0. 22+0.06 0.13+0.05 0.13+0.05 5.7 6.0 5.5 5.7 69 Nov. 22 < 0.04 0. 17+0.05 0.13+0.05 0.13+0.05 6.8 6.2 6.3 6.4 * Error associated with the experimental procedure (See Appendix IV). 63 - On D e c e m b e r 2 4 , 1 9 7 9 , t h e i n f l o w p i p e t o t h e PVC r a c e w a y was a c c i d e n t a l l y k n o c k e d o f f a n d a l l t h e f i s h i n t h e r a c e w a y d i e d . T h e c o u n t o f d e a d f i s h was 3 3 0 . T h i s v a l u e i s i n c l o s e a g r e e m e n t w i t h t h e n u m b e r c a l c u l a t e d f r o m t h e a v e r a g e a n d t o t a l w e i g h t s ( T a b l e 9 ) . T h e a p p a r e n t d i s - a g r e e m e n t i n t h e f i g u r e s f o r t h e o t h e r r a c e w a y s a n d b e t w e e n t h e c a l c u l a t e d n u m b e r o f f i s h o n S e p t e m b e r 15 a n d o n N o v e m b e r 22 c a n be e x p l a i n e d b y t h e e r r o r s a s s o c i a t e d w i t h t h e w e i g h i n g p r o c e s s ( S e c t i o n 5 . 3 ) . 5 . 4 . 1 C a r r y i n g c a p a c i t y a n d s t o c k i n g d e n s i t y T h e c a r r y i n g c a p a c i t y a n d s t o c k i n g d e n s i t y f o r t h e r a c e w a y s a r e s u m m a r i z e d i n T a b l e 1 2 . N o t e t h a t v a l u e s f a r i n e x c e s s o f t h o s e r e c o m m e n d e d f o r r a c e w a y s ( T a b l e 1) w e r e o b t a i n e d . N o t e a l s o t h a t t h e v a l u e s o b t a i n e d w e r e n o t maximum p o s s i b l e l o a d i n g r a t e s , a n d t h a t t h e p e a k l o a d i n g s w e r e n o t r e a c h e d s i n c e n e i t h e r d i s s o l v e d o x y g e n n o r ammon ia h a d r e a c h e d l i m i t i n g l e v e l s . I t s h o u l d b e p o i n t e d o u t t h a t t h e s e r e s u l t s a r e n o t u n i q u e . O t h e r w o r k e r s h a v e r e p o r t e d s i m i l a r c a r r y i n g c a p a c i t i e s a n d s t o c k i n g d e n s i t i e s : B u s s a n d c o - w o r k e r s 3 (1970) o b t a i n e d 1 .6 - 1 . 8 k g / l / m i n a n d 1 2 0 - 1 3 6 k g / m . P i p e r 3 (1970) r e p o r t e d a s t o c k i n g d e n s i t y o f 90 k g / m i n a l u m i n u m t r o u g h s ( t h e s i z e o f t h e t r o u g h s a n d t h e c a r r y i n g c a p a c i t y w e r e n o t s t a t e d ) . K i n c a i d a n d c o - w o r k e r s (1976) o b t a i n e d Table 12. C a r r y i n g c a p a c i t y * a n d s t o c k i n g d e n s i t y * * of the raceways a t v a r i o u s stages o f the experiments. Flow Rate C a r r y i n g C a p a c i t y Stocking D e n s i t y Date Raceway l/min m 3/s kg/nr^s kg/l/min kg/m3 Aug. 15 PVC-1 5 8.3xl0~ 5 1.94xl0 4 0.322 29.8 PVC-2 5 8.3xl0~ 5 1.92xl0 4 0.321 29.7 Sept. 15 PVC-1 5 8.3xl0~ 5 3.02xl0 4 0.505 46.7 PVC-2 5 8.3xl0~ 5 3.35xl0 4 0.559 51.8 Sept. 15 PVC 5 8.3xl0~ 5 2.49xl0 4 0.416 38.5 Rectangular 5 8.3xl0~ 5 2.48x10 0.414 38.4 CSP 5 8.3x10" 5 2.50xl0 4 0.417 38.6 Nov. 22 PVC 5 8.3xl0~ 5 8.99xl0 4 1.501 139.0 Rectangular 5 8.3xl0~ 5 9.01xl0 4 1.504 139.3 CSP 5 8.3xl0~ 5 8.42xl0 4 1.407 130.3 * C a r r y i n g C a p a c i t y = (Weight o f F i s h ) / ( F l o w Rate). ** S t o c k i n g D e n s i t y = (Weight of Fish)/(Volume of Raceway). - 65 - s t o c k i n g d e n s i t i e s as hig h as 170 kg/m Jin 8.8 l i t e r c i r c u l a r tanks and c a r r y i n g c a p a c i t i e s of 1.58 kg/l/min i n 37.5 l i t e r c i r c u l a r tanks. C a l c u l a t i o n s o f s t o c k i n g d e n s i t i e s and c a r r y i n g c a p a c i t i e s u s i n g the procedures proposed by v a r i o u s r e s e a r c h e r s (Willoughby, 1968; Westers, 1970; Westers and P r a t t , 1977) 3 y i e l d e d values r a n g i n g between 118 and 158 kg/m f o r the s t o c k i n g d e n s i t y and between 1.3 and 1.7 kg/l/min f o r the c a r r y i n g c a p a c i t y . These v a l u e s are i n c l o s e agreement with those obtained e x p e r i m e n t a l l y . The r e s u l t s obtained i n our experiments, and i n the t r i a l s performed by other workers (as mentioned above), together w i t h the v a l u e s obtained when c a l c u l a t i n g s t o c k i n g d e n s i t y and c a r r y i n g c a p a c i t y i n d i c a t e t h a t most commercial t r o u t farming o p e r a t i o n s are u n d e r u t i l i z i n g t h e i r pond space and water r e s o u r c e s . M o n i t o r i n g of environmental parameters such as d i s s o l v e d oxygen, temperature and ammonia would convince the farmers t h a t l a r g e r f i s h p o p u l a t i o n s can be maintained i n t h e i r ponds without s t r e s s i n g the f i s h . Growing the f i s h a t high d e n s i t i e s r e q u i r e s r e l i a b l e water s u p p l i e s and adequate back up systems t h a t would c o r r e c t any supply f a i l u r e r a p i d l y t o prevent a d e v a s t a t i n g f i s h k i l l . - 66 - 5.4.2 Water q u a l i t y The water q u a l i t y data f o r the p e r i o d i s presented i n Tables 10 and 11. Temperature: No d i f f e r e n c e i n temperature was d e t e c t e d between the i n f l u e n t and the e f f l u e n t . The temperature at day one was 13°C. I t reached a peak of 15°C on day 16. A f t e r t h a t i t s t a r t e d a very g r a d u a l d e c l i n e and a t the end of the experiment (day 69), i t had reached 8°C. D i s s o l v e d oxygen: The d i s s o l v e d oxygen of the water supply o s c i l l a t e d around 7.8 mg/1 i n i t i a l l y and i n c r e a s e d as the temperature dropped. On day 68, when the temperature was 8°C, the d i s s o l v e d oxygen had climbed t o 11.5 mg/1. The d i s s o l v e d oxygen d e p l e t i o n i n the raceways i n c r e a s e d from around 1.2 mg/1 t o a h i g h of 4.9 mg/1. The h i g h e r uses o c c u r r e d towards the end of the t e s t p e r i o d due t o the i n c r e a s e d l o a d i n g . The lowest d i s s o l v e d oxygen v a l u e f o r the e f f l u e n t was 5.7 mg/1. I t o c c u r r e d on day 17 and was caused by a combination of high temperature (15°C) and low d i s s o l v e d oxygen (7.4 mg/1) i n the i n f l u e n t water. A t the end of the t e s t p e r i o d , the d i s s o l v e d oxygen content of the e f f l u e n t was around 7.8 mg/1 even w i t h the heavy oxygen use noted above. - 67 - pH: The pH remained on the a c i d s i d e throughout the experiment. The supply f l u c t u a t e d from a h i g h of 6.8 to a low o f 5.7. The e f f l u e n t had a lower pH than the supply i n a l l cases. The lowest pH was 5.5 and i t oc c u r r e d on day 4 6 when the supply had a pH o f 5.7. Ammonia: The ammonia N i t r o g e n c o n c e n t r a t i o n remained low throughout the experiment. The h i g h e s t v a l u e o b t a i n e d was 0.2 2 + 0.06 mg/1. I t was observed i n the r e c t a n g u l a r raceway on day 9 and i n the PVC raceway on day 46. There was no d e f i n i t e t r e n d f o r the ammonia-N c o n c e n t r a t i o n i n the t h r e e raceways r e l a t i v e to each o t h e r . In oth e r words, no one raceway had a c o n s i s t e n t l y lower or high e r c o n c e n t r a t i o n o f ammonia-N than the other raceways. 5.4.3 Observations on the management of the system The o b s e r v a t i o n s noted i n S e c t i o n 5.3.2 f o r the t h i r d phase of the experiments apply e q u a l l y t o t h i s phase. In a d d i t i o n , i t was noted t h a t the a n t i f o u l i n g p a i n t prevented the growth of algae on the w a l l s o f the CSP and r e c t a n g u l a r raceways. No algae growth was de t e c t e d and the w a l l s were not covered by a sli m y l a y e r as was the case f o r the PVC raceway. - 68 - 5.5 H y d r a u l i c s The r e s u l t s of the h y d r a u l i c s t u d i e s being presented, c h a r a c t e r i z e the flow i n the raceways i n the absence of f i s h . Superimposed on the e s t a b l i s h e d flow p a t t e r n s are the d i s t u r b a n c e s and t u r b u l e n c e generated by f i s h swimming. The q u a n t i f i c a t i o n of the e f f e c t of the f i s h on the flow c h a r a c t e r i s t i c s i s beyond the scope of t h i s t h e s i s . A d e s c r i p t i o n of two events w i l l , however, i l l u s t r a t e the extent of the i n f l u e n c e of the f i s h a c t i v i t y on the h y d r a u l i c c h a r a c t e r i s t i c s of the raceways. The two events are s i m i l a r i n nature but o c c u r r e d a t d i f f e r e n t times and i n d i f f e r e n t raceways. Event 1. On September 3, three f i s h were put i n the CSP raceway t h a t had j u s t been p a i n t e d and f l u s h e d . The f i s h were to be used f o r t e s t i n g the s u i t a b i l i t y of the environment p r i o r to the t r a n s f e r of a l a r g e batch o f f i s h . I t was noted t h a t soon a f t e r the i n t r o d u c t i o n of the t h r e e f i s h , s o l i d wastes s t a r t e d accumulating i n the raceway (Figure 10). T h i s accumulation continued u n t i l the time when the batch of 348 f i s h was i n t r o d u c e d i n the raceway. At t h i s p o i n t , the s o l i d s became suspended i n the t u r b u l e n t water and were e v e n t u a l l y c a r r i e d out of the raceway. I t should F i g u r e 10.- Sediment accumulated i n the CSP raceway w i t h the reduced l o a d i n g . r - 70 - be p o i n t e d out t h a t no n o t i c e a b l e b u i l d - u p of s o l i d s has taken p l a c e s i n c e . Event 2. On December 24, an a c c i d e n t o c c u r r e d which wiped out a l l but t h r e e f i s h i n the PVC raceway. At t h a t time, 333 f i s h had been kept i n t h i s raceway f o r 3-1/2 months without s o l i d s accumulating i n the raceway. A f t e r the a c c i d e n t , the t h r e e s u r v i v o r s were l e f t i n the raceway and f e e d i n g was reduced to a t r a c e . S o l i d s soon s t a r t e d b u i l d i n g up i n the raceway (Figure 11) and had t o be s u c t i o n e d out. Observations throughout the d u r a t i o n o f the experiments w i t h the f i s h r e v e a l e d t h a t the c l e a n i n g or f l u s h i n g a c t i o n was s p o r a d i c and f o l l o w e d p a t t e r n s o f f i s h a c t i v i t y u s u a l l y a s s o c i a t e d w i t h f e e d i n g . The suspension of the sediments and t h e i r subsequent e x i t from the raceways oc c u r r e d a t times of h i g h a c t i v i t y by the f i s h which u s u a l l y took p l a c e around f e e d i n g time. The o b s e r v a t i o n s presented p o i n t out the extent of the i n f l u e n c e of the f i s h on the c h a r a c t e r i s t i c s of the flow i n a raceway. T h i s i n f l u e n c e d e t r a c t s from the u s e f u l n e s s of h y d r a u l i c s t u d i e s of raceways wi t h no f i s h i n them. There are, however, s e v e r a l f a c t o r s t h a t serve as j u s t i f i c a t i o n f o r s t u d y i n g the h y d r a u l i c c h a r a c t e r i s t i c s of t r o u t c u l t u r e u n i t s . F a c t o r s such as: - 7 1 - F i g u r e | j . S e d i m e n t a c c u m u l a t e d i n t h e PVC r a c e w a y w i t h t h e r e d u c e d l o a d i n g . - 72 - The s p o r a d i c nature of the h i g h a c t i v i t y p e r i o d s . T h i s means t h a t the f i s h may be swimming i n c o n d i t i o n s not too f a r removed from the n o - f i s h s i t u a t i o n f o r extended p e r i o d s of time. The very d i f f e r e n t d e n s i t i e s a t which raceways are stocked by d i f f e r e n t o p e r a t o r s and a l s o the i n c r e a s i n g d e n s i t y i n a raceway as a batch of f i s h grows. A l l t h i s means t h a t the e x t e n t of the d i s t u r b a n c e on the n o - f i s h flow p a t t e r n w i l l be h i g h l y v a r i a b l e . - . Perhaps the s t r o n g e s t c o n f i r m a t i o n of the importance of the background flow c h a r a c t e r i s t i c s i n a raceway, comes from the f a c t t h a t very d i f f e r e n t c a r r y i n g c a p a c i t i e s and l o a d i n g d e n s i t i e s can be o b t a i n e d from d i f f e r e n t shapes of impoundments having d i f f e r e n t flow c h a r a c t e r i s t i c s (Table 1). 5.5.1 Flow p a t t e r n s A t o t a l o f f o u r complete runs were made. The photo- graphs showing the movement o f the dye are presented i n F i g u r e s 12 to 15. V i s u a l o b s e r v a t i o n s , not recorded i n photographs were made i n the f o u r complete runs and a l s o i n runs on the CSP raceways. These o b s e r v a t i o n s are d e s c r i b e d below. - 73 - 5.5.1.1 A c r y l i c g l a s s pipe raceway The dye movement i n t h i s raceway i s shown i n F i g u r e s 12 and 13 f o r the two flow r a t e s , 5.0 and 10.0 l/min. In both cases, complete mixing o f the i n f l o w o c c u r r e d almost i n s t a n t a n e o u s l y and no dead spots were d e t e c t e d c l o s e t o the i n l e t , i n d i c a t i n g the presence of a r e g i o n of h i g h t u r b u l e n c e . No dead areas were d e t e c t e d i n the f i r s t h a l f of the raceway. In the second h a l f , a drawdown caused by the l o c a t i o n o f the o u t l e t became apparent. A zone of r a p i d water flow appeared on the lower s e c t i o n o f the raceway with a c o r r e s p o n d i n g stagnant area c l o s e t o the s u r f a c e . The depth of the stagnant area i n c r e a s e d as i t got c l o s e r t o the o u t l e t . Observations from above r e v e a l e d some minor stagnant areas extending back from the o u t l e t end along the s i d e s of the p i p e a d i s t a n c e of about o n e - f i f t h of the raceway l e n g t h . There were no dead areas c l o s e t o the bottom of the raceway. 5.5.1.2 Rectangular raceway The dye movement f o r t h i s raceway is.shown i n F i g u r e s 14 and 15 f o r the 5.0 and 10.0 l/min flow r a t e s . As was the case i n the pipe raceways, a r e g i o n of hi g h i± IB 20 22 Z5 Numbers i n d i c a t e the time (minutes) a f t e r the i n j e c t i o n o f the dye. F i g u r e 12. Flow p a t t e r n s i n the c i r c u l a r raceway at 5 l/min.  F i g u r e 14. Flow p a t t e r n s i n the r e c t a n g u l a r raceway at 5 l/min.  - 78 - tur b u l e n c e o c c u r r e d near the i n l e t and complete mixing of the i n f l o w r e s u l t e d . Dead areas were d e t e c t e d i n "the second h a l f of the raceway. In t h i s case, they were both a t and near the s u r f a c e and the bottom. Dead areas were a l s o present along the s i d e s of the raceway extending back from the o u t l e t . 5.5.1.3 CSP raceways Obs e r v a t i o n s made on these raceways were done from above only. The o u t s t a n d i n g behaviour o f the flow observed was the presence o f dead areas i n the c o r r u g a t i o n s , e s p e c i a l l y c l o s e t o the o u t l e t s . Other than t h a t , no dead areas c o u l d be d e t e c t e d due t o the d i f f i c u l t y i n making the o b s e r v a t i o n s . The l o c a t i o n and extent of the stagnant areas are important f o r the management of the raceways. I f the stagnant area i s a t or c l o s e to the water s u r f a c e , food p a r t i c l e s f a l l i n g i n the water w i l l move s l o w l y downstream and towards the bottom, g i v i n g the f i s h more time t o reach the food. When the food p a r t i c l e s f i n a l l y s i n k , they w i l l e n t e r a r e g i o n o f hi g h e r v e l o c i t y and w i l l be c a r r i e d t o the o u t l e t . Feces from the f i s h w i l l be a f f e c t e d i n a s i m i l a r way by the water flow. I f , on the oth e r hand, the stagnant areas are c l o s e t o the bottom of the raceway, p a r t i c l e s r e a c h i n g them w i l l s e t t l e and sediments w i l l accumulate i n the raceways. Of the raceways t e s t e d , o n l y the c i r c u l a r smooth raceway d i d not show stagnant areas c l o s e t o the bottom. Table 13. Concentration of malachyte green in the effluent of the raceways at time t after the introduction of the dye in the inflow. (Concentration of Malachyte Green mg/1) Flow = 5.0 1/min Flow = 10.0 1/min Time Circular - Rectangular CSP (25 cm) CSP (20 cm) Circular Rectangular CSP (25 cm) CSP (20 cm) (min) Raceway Raceway Raceway Raceway Raceway Raceway Raceway Raceway 2.0 2.5 3.0 3.5 0.00 4.0 0. 00 0.05 4.5 0. 63 0.00 5.0 0. 00 1.70 0.15 5.5 1.94 0. 29 6.0 0.34 1.07 2.52 0.49 6.5 1.70 2.67 0.73 7.0 0.97 2.14 2.33 1.41 7.5 1.12 2. 23 1.89 1.46 8.0 1.26 2. 77 1. 60 1.57 8.5 1.55 9.0 1.70 2.48 1.41 1.82 9.5 1.36 10.0 1.07 2. 09 1.07 1.75 10.5 1.12 11.0 0.87 1. 36 0.63 1.36 12.0 0.53 1.12 0.25 1.12 13.0 0.39 0. 78 0.24 14.0 0.39 0.19 0.63 15.0 0.24 0.39 16.0 0.10 0.34 17.0 0.15 18.0 0.02 0. 29 19.0 0.10 0.00 0.00 0.00 0.05 1.55 0.05 0.10 0.68 3.01 0.00 3.11 4.76 4. 27 6.12 5. 63 6.12 3.40 0.31 6.22 6.12 3. 20 0.63 5.15 4. 57 2.67 1.07 3.79 3.35 2.57 2.09 1.84 1.55 1.89 1.60 1.21 1.21 0.97 0.58 1.17 0.97 0.63 0.58 0.68 0.49 0.44 0.92 0.39 0.29 0.24 0.39 0.53 0.24 0.15 0.15 0.44 0.24 0.05 0.10 - 80 - 4H 2-J ~ k A Rectangular racaway E Ul or o ui x t\ u < 2 *• u o u 24 Circular racaway 0.25 m dia. CSP racaway 0.20 m dia. CSP racaway TIME AFTER INJECTION (min) F i g u r e 16. C o n c e n t r a t i o n o f malachyte green vs, time a t 5 l/min. - 81 - TIME AFTER INYECTION [min] F i g u r e 17. C o n c e n t r a t i o n o f malachyte green v s . time a t 10 l/min. Table 14. Normalized c o n c e n t r a t i o n values a t 5 l/min. E-values (l/min) Time C i r c u l a r Rectangular 0.25 m CSP 0.20 m CSP (min) Raceway Raceway Raceway v Raceway 3.5 0.000 4.0 0.000 0.004 4.5 0.052 0.000 5.0 0.000 0.140 0.012 5.5 0.160 0.022 6.0 0.038 0.070 0.208 0.038 6.5 0.111 0.221 0.056 7.0 0.108 0.140 0.193 0.108 7.5 0.124 0.146 0.156 0.112 8.0 0.140 0.181 0.132 0.121 8.5 0.172 9.0 0.189 0.162 0.117 0.140 9.5 0.151 10.0 0.119 0.137 0.088 0.135 10.5 0.124 11. 0 0.097 0.089 0.052 0.105 12. 0 0.059 0.073 0.021 0.086 13. 0 0.043 0.051 0.020 14.0 0.043 0.016 0.048 15.0 0.027 0.025 16.0 0.008 0.026 17. 0 0.010 18.0 0.002 0.022 19.0 0.007 T a b l e 15. Normalized c o n c e n t r a t i o n v a l u e s a t 10 1/min. E-values (1/min) Time C i r c u l a r Rectangular 0.25 m CSP 0.20 m CSP (min) Raceway Raceway . Raceway Raceway 2.0 0.000 0.000 2.5 0.000 0.003 0.117 0.007 3.0 0.006 0.043 0.226 0.000 3.5 0.187 0.299 0.321 0.017 4.0 0.339 0.385 0.256 0.043 4.5 0.375 0.385 0.241 0.088 5. 0 0.310 0.287 0.201 0.149 5.5 0.225 0.211 6.0 0.155 0.131 0.138 0.215 6.5 0.114 0.101 0.091 7.0 0.073 0.061 0.044 0.163 7.5 0.058 0.040 0.044 8.0 0.041 0.031 0.033 0.128 8.5 0.023 9.0 0.017 0.015 0.029 0.074 9.5 10.0 0.014 0.009 0.011 0.061 10.5 11.0 0.014 . 0.003 0.008 - 84 - 5.5.2 Residence time d i s t r i b u t i o n The o r i g i n a l c o n c e n t r a t i o n versus time data i s presented i n Table 13 and p l o t t e d i n F i g u r e s 16 and 17. The curves were e x t r a p o l a t e d and the area under each curve was measured u s i n g a Numonics Graphics C a l c u l a t o r ( e l e c t r o n i c p l a n i m e t e r ) . The d i s t r i b u t i o n was then normalized by d i v i d i n g the c o n c e n t r a t i o n by the area under the c o n c e n t r a t i o n v e r s u s time curve o b t a i n i n g E, w i t h u n i t s of 1/time. The normalized c o n c e n t r a t i o n , E, was then p l o t t e d a g a i n s t time and the E-curves were ob t a i n e d ( L e v e n s p i e l , 1972) and are shown i n F i g u r e s 18 and 19. At the 5 l/min flow r a t e , the dye was d e t e c t e d e a r l i e r i n the 0.25 m diameter CSP raceway than i n the o t h e r s . T h i s i n d i c a t e s the presence of a more marked s h o r t c i r c u i t i n g stream. The c i r c u l a r and r e c t a n g u l a r raceways have ve r y s i m i l a r r e s i d e n c e time d i s t r i b u t i o n s i n d i c a t i n g t h a t they e x h i b i t approximately the same e x t e n t of s h o r t c i r c u i t i n g and of i n t e r m i x i n g . The 0.20 m diameter CSP raceway has the l e a s t s h o r t c i r c u i t i n g of the f o u r raceways s t u d i e d . The lower peak of dye i n the e f f l u e n t and the slower decay i n d i c a t e t h a t t h e r e i s a l a r g e degree of i n t e r m i x i n g t a k i n g p l a c e i n t h i s raceway. A t the 10 l/min f l o w r a t e , the raceways behaved i n much the same manner as they had a t the lower 5 l/min flow r a t e . The 0.25 m diameter CSP raceway agai n e x h i b i t e d the most marked s h o r t c i r c u i t i n g w h i l e the 0.20 m diameter CSP raceway e x h i b i t e d the l e a s t . I t should be remembered t h a t the 0.25 m diameter raceway was f i l l e d t o a depth of 0.4 times the diameter w h i l e the 0.20 m diameter CSP and the c i r c u l a r raceways - 84a - were both f i l l e d t o 0.8 times the diameter, but a l l three had the same c r o s s - s e c t i o n a l area. - OD - TIME AFTER INJECTION (min) F i g u r e 18. E -curves a t 5 l/min. TIME AFTER INJECTION (min) F i g u r e 1 9 . E - c u r v e s a t 10 1 / m i n . 6. CONCLUSIONS 1. G a l v a n i z e d s t e e l raceways are u n s u i t a b l e f o r h o l d i n g rainbow t r o u t , Salmo g a i r d n i e r i , under the c o n d i t i o n s o f the t e s t , even a f t e r f l u s h i n g f o r 64 days. 2. The g a l v a n i z e d CSP raceways are s u i t a b l e f o r h o l d i n g rainbow t r o u t when the i n s i d e i s coated w i t h i n t e r - r a c i n g a n t i f o u l i n g p a i n t as was done i n these experiments. 3. The p a i n t used, i n t e r - r a c i n g a n t i f o u l i n g produced by I n t e r n a t i o n a l P a i n t s , i s not t o x i c t o the f i s h and i t reduces the growth of algae on the w a l l s o f the raceways. 4. F i s h can be grown i n raceways of c i r c u l a r c r o s s - s e c t i o n . * 5. Rainbow t r o u t f i n g e r l i n g s ( i n i t i a l weight 6.0 g) grew f a s t e r i n the CSP raceway than i n the r e c t a n g u l a r raceway and the PVC raceway. 6. The raceways are s e l f - c l e a n i n g under the c o n d i t i o n s of water flow r a t e and f i s h d e n s i t i e s t e s t e d . - 88 - The term s e l f - c l e a n i n g as used here means t h a t there i s no accumulation of s o l i d s i n the raceways. 7 . F i s h can be grown i n the raceways t e s t e d a t much high e r d e n s i t i e s (weight of f i s h / volume of pond) than those r e p o r t e d f o r c o n v e n t i o n a l raceways. 8. No major d i f f e r e n c e s between the h y d r a u l i c c h a r a c t e r i s t i c s of the raceways were found. 9. The f i s h a f f e c t the c h a r a c t e r i s t i c s o f the flow i n the raceways. Sediments d i d not accumulate i n the raceways stocked w i t h f i s h , but the sediments d i d b u i l d up when the raceways had onl y a few f i s h i n them. - 89 - 7. RECOMMENDATIONS AND SUGGESTIONS FOR FUTURE WORK During the experiments, s e v e r a l problems were encountered i n the management of the raceways. What f o l l o w s are some suggestions f o r m o d i f i c a t i o n s of the raceways. 1. Locate the i n l e t c l o s e r to the head end of the raceway. In the pr e s e n t s e t up, the i n f l o w i s coming i n approximately 0.3 m from the head end of the raceway. The present l o c a t i o n o f the i n l e t causes backflows. 2. Improve the n e t t i n g c l o s e to the ends of the raceways. There were s e v e r a l cases of f i s h jumping out c l o s e t o the ends of the raceways due to improperly a d j u s t e d and p o o r l y f i t t i n g e n c l o s i n g n e t s . 3. Increase the s i z e of the screen on the e f f l u e n t p i p e . T h i s can be achieved by one or a combination of s e v e r a l of the f o l l o w i n g means: a. M a i n t a i n i n g the same s l a t width and spacing between s l a t s , i ) i n c r e a s e the diameter of the p i p e , or i i ) i n c r e a s e the l e n g t h of pi p e i n the raceway - 90 - b. Increase the number of s l a t s on the p i p e c. Increase the s i z e o f the s l a t s . 4. Increase the diameter o f the p i p e c a r r y i n g the e f f l u e n t from the o u t l e t box, to prevent the system from backing up and o v e r f l o w i n g . 5. P r o v i s i o n f o r the complete drainage of the raceways should be made by i n s t a l l i n g a plu g on the bottom of the raceways. 6. I n s t a l l a bottom d r a i n on the o u t l e t box f o r the removal of s o l i d s accumulated i n the box. a. Experiments i n s c a l e d up raceways. The r e s u l t s of the s c a l e d up experiments would t e l l how good the models were f o r p r e d i c t i n g the behaviour of the l a r g e s c a l e raceways. The c o n c l u s i o n s presented i n S e c t i o n 6 should apply t o the l a r g e s c a l e raceways. F i s h management c o n s i d e r a t i o n s l i m i t the depth o f the l a r g e s c a l e c i r c u l a r raceways to a maximum diameter o f 1.0 m. The flow r a t e and l e n g t h should be determined by the use of the model laws as o u t l i n e d i n 7.1 Suggestions f o r Future Work - 91 - S e c t i o n 2.2. For a 1.0 m diameter raceway, f i l l e d to 0.3 times the diameter, the l e n g t h of the raceway would be 12.2 m. The flow r a t e f o r such a raceways would be 280 l/min (corresponding to the 5 l/min flow r a t e i n the model). At the same c a r r y i n g c a p a c i t y as the model, the l a r g e raceway c o u l d c a r r y 419 kg. The s t o c k i n g d e n s i t y i n t h i s 3 case would be 61.7 kg/m . The s t o c k i n g d e n s i t y c o u l d be i n c r e a s e d i f the flow r a t e were i n c r e a s e d . The upper l i m i t on the flow r a t e i s determined based on the amount of energy used up by the f i s h swimming i n the raceway. b. Experiments i n the model raceways to determine i f the h i g h s t o c k i n g d e n s i t y a f f e c t s the growth r a t e of the f i s h even b e f o r e s t r e s s f u l l e v e l s of d i s s o l v e d oxygen or ammonia are reached. T h i s would i n v o l v e s t o c k i n g equal raceways a t d i f f e r e n t d e n s i t i e s and comparing the growth of the f i s h . c. Compare the growth r a t e of f i s h r e a r e d i n raceways, c i r c u l a t i n g tanks, and v e r t i c a l u n i t s . A l l the u n i t s would be stocked a t a predetermined optimum l e v e l . d. T e s t the g a l v a n i z e d CSP raceways under d i f f e r e n t water c o n d i t i o n s . Water s u p p l i e s of d i f f e r e n t hardness should be used. - 92 - LITERATURE CITED A f f l e c k , R.J. 1952. Z i n c p o i s o n i n g i n a trout, hatchery. Aust. Jour, o f Marine and Freshwater Res., 3 (2):142-169. American P u b l i c H e a l t h A s s o c i a t i o n . 1976. Standard Methods f o r the Examination of Water and Wastewater, 14th e d i t i o n . American P u b l i c H e a l t h A s s o c i a t i o n , Inc., Washington. Bardach, John E., W.O. McLarney, J.H. Ryther. 1972. Aquaculture; the farming and husbandry of freshwater and marine organisms. John Wiley. Binder, R.C. 1973. F l u i d Mechanics. F i f t h e d i t i o n . P r e n t i c e H a l l , London. Boyd, C E . 1977. E v a l u a t i o n of a water a n a l y s i s k i t . J . E n v i r o n . A n a l . , 6 ( 4 ) : 381-384. Brown, V.M. 1968. 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Westers, H. and K.M. P r a t t . 1977. The r a t i o n a l d e s i g n of f i s h h a t c h e r i e s based on c h a r a c t e r i s t i c s of f i s h metabolism. The Prog. F i s h C u l t . 39(4). Wheaton, F.W. 1977. A q u a c u l t u r a l E n g i n e e r i n g . John Wiley and Sons. Willoughby, H. 1968. A Method f o r c a l c u l a t i n g c a r r y i n g c a p a c i t i e s of hatchery troughs and ponds. The Prog. F i s h C u l t . 30(3): 173-174. Zi n c Development A s s o c i a t i o n . 1965. Atmospheric c o r r o s i o n r e s i s t a n c e of Z i n c . Z i n c Dev. Assoc., London. American Z i n c I n s t i t u t e , New York. - 96 - APPENDICES - 97 - APPENDIX I-A. Corrugated S t e e l Pipe Raceway. Two s i z e s o f CSP raceways were b u i l t . Some from 0.20 m diameter p i p e and some from 0.25 m diameter p i p e . F i g u r e 1-1 shows the 0.20 m diameter raceway. The CSP used was h e l i c a l p i p e meaning t h a t the seam of the s t e e l p l a t e runs h e l i c a l l y along the l e n g t h of the p i p e . The w a l l t h i c k n e s s was 0.13 cm (18 gauge). The ends were capped w i t h 2.5 cm t h i c k gumwood d i s c s . The d i s c s were f i r s t screwed i n p l a c e and then the v o i d s were f i l l e d w i t h p o l y s u l f i d e c a u l k i n g compound to achieve a w a t e r - t i g h t s e a l . The p o l y s u l f i d e s e a l a n t was coated w i t h a n t i f o u l i n g p a i n t on the i n s i d e o f the raceway. Rectangular openings were c u t on the raceway as shown i n F i g u r e 1-1. Care should be taken t o a v o i d the seams of the pip e when making the h o l e s . The hol e s were made by d r i l l i n g on two opposing c o r n e r s of the hole t o be c u t and then c u t t i n g the metal u s i n g a jigsaw. When the raceways were p a i n t e d f o r the f o u r t h phase of the experiment, a z i n c chromate primer was a p p l i e d p r i o r t o the a p p l i c a t i o n of the green a n t i f o u l i n g p a i n t . Section A-A APPENDIX FIGURE 1 - 1 . Corrugated S t e e l Pipe Raceway. Dimensions i n meters. - 99 - APPENDIX I-B. PVC Raceway. The PVC r a c e w a y s w e r e b u i l t f r o m 0.20 m d i a m e t e r PVC p i p e o f 0.6 cm w a l l t h i c k n e s s . The end c a p s w e r e made f r o m 0.6 m t h i c k PVC s h e e t i n g . Two d i s c s w e r e c u t , one t o f i t i n s i d e t h e p i p e a n d t h e o t h e r h ad t h e same d i a m e t e r a s t h e p i p e . The two d i s c s w e r e g l u e d t o g e t h e r a nd t h e n g l u e d t o t h e e n d s o f t h e r a c e w a y s . R e c t a n g u l a r o p e n i n g s w e r e c u t i n t h e t o p o f t h e r a c e w a y s a s shown i n F i g u r e 1-2. The p r o c e d u r e u s e d f o r c u t t i n g t h e o p e n i n g s was s i m i l a r t o t h a t d e s c r i b e d f o r t h e CSP r a c e w a y s . o Section A-A APPENDIX FIGURE 1 - 2 . PVC Raceway. Dimensions i n meters. i - 101 - APPENDIX I-C. Rectangular Raceway f o r F i s h T r i a l s . The r e c t a n g u l a r raceway was b u i l t from 3.8 cm t h i c k f i r planks. The wood was glued and screwed together. I t was then primed and f i n a l l y two coats of green a n t i f o u l i n g p a i n t were a p p l i e d . The seams were then s e a l e d w i t h s i l i c o n e s e a l a n t . The raceway i s shown i n F i g u r e 1-3. 0 0.04 .24 0.04 0.04 2.44 0 0 4 K)05 He* 0.16 10.20 _ £ ooT 1 —r APPENDIX FIGURE 1-3. Rectangular Raceway f o r F i s h T r i a l s . Dimensions i n meters. - 103 - A P P E N D I X I - D . A c r y l i c G l a s s P i p e R a c e w a y . T h e a c r y l i c g l a s s p i p e r a c e w a y was b u i l t f r o m 0 . 2 0 m d i a m e t e r p i p e o f 0 . 6 cm w a l l t h i c k n e s s . T h e p i p e was a v a i l a b l e i n maximum l e n g t h s o f 1 . 8 m s o a j o i n t h a d t o b e made i n o r d e r t o o b t a i n t h e d e s i r e d 2 . 4 4 m l e n g t h . R e c t a n g u l a r o p e n i n g s w e r e c u t i n t h e p i p e a s s h o w n i n F i g u r e 1 - 4 . T h e e n d c a p s w e r e d i s c s o f 0 . 6 cm t h i c k n e s s . Section A - A —r o.osX ZJ LZ Io« 0 05 022 0.1 1 2*4- o APPENDIX FIGURE 1-4. A c r y l i c Glass Pipe Raceway. Dimensions i n meters. i - 105 - A P P E N D I X I - E . R e c t a n g u l a r R a c e w a y f o r H y d r a u l i c S t u d i e s . T h i s r a c e w a y w a s b u i l t f r o m w o o d a n d a c r y l i c g l a s s ( F i g u r e 1 - 5 ) . T h e b o t t o m a n d e n d s w e r e 3 . 8 cm t h i c k f i r . The s i d e s w e r e 0 . 6 cm a c r y l i c g l a s s . V e r t i c a l s u p p o r t s w e r e p l a c e d a l o n g t h e s i d e s t o p r e v e n t t h e a c r y l i c g l a s s f r o m b e n d i n g . T h e v e r t i c a l members w e r e 2 . 5 cm w i d e b y 0 . 6 cm t h i c k s t e e l s e c t i o n s . F u r t h e r s u p p o r t was p r o v i d e d b y h o r i z o n t a l w o o d p i e c e s a l o n g t h e t o p a n d b o t t o m e d g e s o f t h e s i d e s . T h e t o p p i e c e s w e r e c o n n e c t e d b y c r o s s - p i e c e s t o p r e v e n t t h e a c r y l i c g l a s s f r o m b e n d i n g o u t when t h e r a c e w a y was f i l l e d . T h e wood was p r i m e d p a i n t e d w i t h w h i t e m a r i n e e n a m e l . The seams w e r e s e a l e d w i t h s i l i c o n e s e a l a n t . APPENDIX FIGURE 1-5. Rectangular Raceway f o r H y d r a u l i c S t u d i e s . Dimensions i n meters. - 107 - APPENDIX I-F. Stands f o r the Raceways. Stands f o r s u p p o r t i n g the raceways were made from 2"x4" (nominal s i z e ) (5x10 cm) f i r . End s e c t i o n s of 1.8 cm plywood were added to p r o v i d e support f o r the constant head tower and to improve the s t a b i l i t y of the s t r u c t u r e . T r i a n g u l a r braces of plywood were a l s o i n s t a l l e d as shown i n F i g u r e 1-6. APPENDIX FIGURE 1-6. Stands f o r the Raceways. Dimensions i n meters. - 109 - APPENDIX I-G. O u t l e t B o x e s . The o u t l e t b o x e s a r e c o n s t r u c t e d f r o m 0.10 m d i a m e t e r PVC p i p e . H o l e s a r e d r i l l e d a n d t h r e a d e d f o r 1" (2.5 cm) I.D. p i p e a s shown i n F i g u r e 1-7. The s l o t s on t h e o u t l e t p i p e a r e 0.3 cm w i d e , 1.3 cm deep and 1.3 cm a p a r t . They w e r e c u t i n a m i l l i n g m a c h i n e . The o u t l e t p i p e i s h e l d i n p l a c e by two t h r e a d e d d i s c s , one on e a c h s i d e o f t h e end w a l l . S i l i c o n e s e a l a n t i s u s e d t o p r e v e n t l e a k s . The p i p e c a r r y i n g t h e e f f l u e n t f r o m t h e o u t l e t b o x i s 1.9 cm I.D. f l e x i b l e p l a s t i c p i p e . The o u t f l o w a n d w a t e r l e v e l c o n t r o l u n i t s a r e e n t i r e l y m a n u f a c t u r e d f r o m PVC p a r t s e x c e p t f o r t h e p i p e c a r r y i n g t h e e f f l u e n t f r o m t h e o u t l e t b o x . 0.013 =^=~&i^ 0.20 0.33 4 T (i 8 § r— 6 6 M I—1 O APPENDIX FIGURE 1-7. O u t l e t Box. Dimensions i n meters. APPENDIX I-H. Constant Head Tower. The constant head boxes were b u i l t from 1.1 cm plywood. The f i t t i n g s are a l l PVC (Figure 1-8). A f t e r assembly, the wood was primed and two coats o f green a n t i f o u l i n g p a i n t were a p p l i e d . The seams were s e a l e d w i t h s i l i c o n e s e a l a n t . APPENDIX FIGURE 1-8. Constant Head Towers. Dimensions i n meters. - 113 - APPENDIX I I . Drawings and Discharge Data f o r O r i f i c e s . The o r i f i c e s were d r i l l e d on PVC caps f o r 5 cm (2") I.D. pi p e . They were countersunk from the o u t s i d e a t 4 5°. The o r i f i c e s i z e s were determined from the equation Q = (Binder, 1973), where Q i s the d i s c h a r g e , c i s a constant f o r the o r i f i c e , d i s the o r i f i c e diameter, g i s the a c c e l e r a t i o n due t o g r a v i t y and H i s the head above the o r i f i c e . Once c a l c u l a t i o n s f o r an o r i f i c e s i z e were made u s i n g an assumed cons t a n t c, an o r i f i c e was made (Figure I I - l ) and the d i s c h a r g e through i t was measured. From t h i s data, a new estimate f o r c was o b t a i n e d . T h i s e s timate was used i n a second s e t of c a l c u l a t i o n s and the r e q u i r e d o r i f i c e diameter was found. Four o r i f i c e s were made and t e s t e d (Table I I - l ) . -5 3 The d e s i r e d flow was 5 1/min or 8.3x10 m /s. The head was 0.22 m. With a con s t a n t c = 0.65, the r e q u i r e d diameter was found t o be 0.87 cm (11/32"). The o r i f i c e s were d r i l l e d and t e s t e d (Table I I - l ) . - 114 - APPENDIX TABLE I I - l . Discharge Data f o r O r i f i c e s , diameter = 0.87 cm, head = 0.22 m. Date O r i f i c e Number Discharge (l/min) J u l y 24/79 1 4.8 2 4.8 3 5.0 4 4.8 Sept. 24/79 1 4.9 2 5.0 3 5.0 APPENDIX FIGURE I I - l . O r i f i c e . Dimensions i n meters. - 116 - APPENDIX I I I , Data Sheet f o r I n t e r - r a c i n g A n t i f o u l i n g Green P a i n t . Manufacturer: I n t e r n a t i o n a l P a i n t s (Canada) Ltd, V e h i c l e Type Pigment: So l v e n t : Rosin and other f i l m formers Cuprous oxide, Phthalo green, Hansa y e l l o w Aromatic hydrocarbons F l a s h P o i n t : 2 6°C % S o l i d s by Volume: 53 Recommended Dry F i l m _r> Th i c k n e s s : 5.08 x 10 m 2 -5 T h e o r e t i c a l Coverage: 12.5 m per l i t r e at 5.08x10 m D.F.T, Dry Time: Touch: Hard: 2-3 hours 6 hours Overcoating: C o l o u r : Overnight Green F i n i s h : Semi-gloss Method of A p p l i c a t i o n : B r u s h S h ipping Weight: 7. 2 kg, Thinner: 073102 - 117 - APPENDIX IV. Comparison o f the Hach and Auto-analyzer Methods o f Measuring Ammonia. Ammonia was measured u s i n g a Hach DR-EL/2 D i r e c t Reading Engineer's Laboratory K i t (Hach Chemical Co., Ames, Iowa), and a Technicon Auto A n a l y z e r II (Technicon I n d u s t r i a l Systems, Tarrytown, N.Y.). The procedures f o r the t e s t s are presented i n Appendices V and VI. Samples were c o l l e c t e d d a i l y from the e f f l u e n t of each of the raceways and from the water supply. The samples were s t o r e d i n a r e f r i g e r a t o r at 4°C. The pH was approximately 6.1. On the f i f t h day of c o l l e c t i o n , a l l the samples (15 i n t o t a l ) were analyzed u s i n g both the Hach K i t and the a u t o - a n a l y z e r . The r e s u l t s are presented i n Table IV-1 and p l o t t e d i n F i g u r e IV-1. The a u t o - a n a l y z e r value i s assumed to be the c o r r e c t v alue (Boyd, 1977). A r e g r e s s i o n equation i s o b t a i n e d as f o l l o w s y = 0.45 x - 0.10 where y i s the ammonia c o n c e n t r a t i o n i n mg/1 of ammonia-N, x i s the Hach k i t r e a d i n g a l s o i n mg/1 of ammonia-N. The c o r r e l a t i o n c o e f f i c i e n t f o r the r e l a t i o n s h i p i s r = 0.905. - 118 - A P P E N D I X T A B L E I V - 1 , A m m o n i a - N M e a s u r e d W i t h t h e H a c h K i t a n d t h e T e c h n i c o n A u t o - A n a l y z e r . A m m o n i a - N (mg/1) Day o f S a m p l e C o l l e c t i o n S u p p l y E f f l u e n t F r o m R e c t a n g u l a r R a c e w a y E f f l u e n t F r o m CSP R a c e w a y A u t o - A u t o - A u t o - H a c h A n a l y z e r H a c h A n a l y z e r H a c h A n a l y z e r M o n d a y 0 . 2 8 0 . 0 0 6 0 . 4 5 0 . 1 1 J 0 . 4 5 0 . 0 7 5 T u e s d a y 0 . 2 5 0 . 0 1 1 0 . 4 0 0 . 1 3 5 0..45 0 . 1 1 3 W e d n e s d a y 0 . 2 5 0 . 0 0 7 0 . 4 3 0 . 0 7 6 0 . 4 0 0 . 0 8 6 T h u r s d a y - 0 . 2 2 0 . 0 0 6 0 . 4 0 0 . 0 7 3 0 . 4 0 0 . 0 9 3 F r i d a y 0 . 2 1 0 . 0 0 7 0 . 4 0 0 . 0 7 8 . 0 . 4 5 0 . 0 9 5 N o t e : a l l s a m p l e s w e r e a n a l y z e d o n F r i d a y . APPENDIX FIGURE IV- 1 . A u t o - a n a l y z e r v s . Hach K i t Readings of the Ammonia-N Content o f Samples. • a 0.20 0.30 0.40 0.50 HACH KIT VALUE ( mg/I Ammonia - N ) - 120 - Furthermore, a 95% conf i d e n c e i n t e r v a l f o r s i n g l e measurements of the ammonia c o n c e n t r a t i o n can be c o n s t r u c t e d using a t - s t a t i s t i c as f o l l o w s (Walpole and Myers, 1972): y = 0.45 x - 0.10 + t Q 0 5 ^ 2 S where t„ n r ,~ •= 2.16 f o r n - 2 = 13 degrees of freedom 0.0 b / 2. n - 15 The c o n f i d e n c e i n t e r v a l i s p l o t t e d i n F i g u r e IV-1. A n a l y s i s of prepared standard ammonia s o l u t i o n s i n the Hach k i t , y i e l d e d v a l u e s ranging from 63% to 127% of the known c o n c e n t r a t i o n s . - 121 - The a u t o a n a l y z e r a n a l y s i s were o f f by a maximum of 5% of the known c o n c e n t r a t i o n . In c o n t r a s t , on the a n a l y s i s of the samples from the water supply, the Hach k i t y i e l d e d values which were up to 50 times those o b t a i n e d by the autoanalyzer. T h i s r e s u l t s would i n d i c a t e the presence of i n t e r f e r i n g agents i n the water supply. The i n t e r f e r i n g agents are not i d e n t i f i e d and the Hach K i t should be c a l i b r a t e d f o r each water supply i n a manner s i m i l a r t o t h a t presented here. - 122 - APPENDIX V. Procedure f o r Measuring Ammonia Using the Hach K i t . N e s s l e r Method. Range: 0-2 mg/1 , Procedure: 1. Take a water sample by f i l l i n g a c l e a n 25-ml graduated c y l i n d e r t o the 25-ml mark. Pour i n t o a c l e a n sample c e l l . 2. Measure 25 ml of d e m i n e r a l i z e d water by f i l l i n g another c l e a n 25-ml graduated c y l i n d e r t o the 25-ml mark.Pour the d e m i n e r a l i z e d water i n t o another c l e a n sample c e l l . 3. Using the 1-ml c a l i b r a t e d dropper, add 1 ml of N e s s l e r Reagent to each sample c e l l and s w i r l t o mix. A y e l l o w c o l o r w i l l develop i f ammonia n i t r o g e n i s p r e s e n t . Allow a t l e a s t 10 minutes, but not more than 25 minutes f o r the c o l o r t o f u l l y develop b e f o r e performing Steps 4 and 5. 4. P l a c e the sample c e l l c o n t a i n i n g the prepared de- m i n e r a l i z e d water s o l u t i o n i n the c e l l h o l d e r . I n s e r t the N i t r o g e n , Ammonia (Nessler Method) Meter S c a l e i n the meter and a d j u s t the Wavelength D i a l t o 425 nm. A d j u s t the LIGHT CONTROL f o r a meter r e a d i n g of zero mg/1. 5. P l a c e the prepared sample i n the c e l l h o l d e r and read the mg/1 ammonia n i t r o g e n (N). A P P E N D I X V I . P r o c e d u r e f o r M e a s u r i n g Ammon ia w i t h t h e A u t o - A n a l y z e r . I n d u s t r i a l M e t h o d N o . 154-71W R a n g e : 0-14 0 j ) l g / l G e n e r a l D e s c r i p t i o n T h e a u t o m a t e d p r o c e d u r e f o r t h e d e t e r m i n a t i o n o f ammon ia u t i l i z e s t h e B e r t h e l o t R e a c t i o n , i n w h i c h t h e f o r m a t i o n o f a b l u e c o l o r e d c o m p o u n d b e l i e v e d t o b e c l o s e l y r e l a t e d t o i n d o p h e n o l o c c u r s when t h e s o l u t i o n o f a n ammonium s a l t i s a d d e d t o s o d i u m p h e n o x i d e , f o l l o w e d b y t h e a d d i t i o n o f s o d i u m h y p o c h l o r i t e . A s o l u t i o n o f p o t a s s i u m s o d i u m t a r t r a t e a n d s o d i u m c i t r a t e i s a d d e d t o t h e s a m p l e s t r e a m t o e l i m i n a t e t h e p r e c i p i t a t i o n o f t h e h y d r o x i d e s o f c a l c i u m a n d m a g n e s i u m . P e r f o r m a n c e a t 60 S a m p l e s P e r H o u r U s i n g A q u e o u s S t a n d a r d s S e n s i t i v i t y a t 10 ^ g a t N/1 0.15 (140 ^ g N/1) a b s o r b a n c e u n i t s C o e f f i c i e n t o f V a r i a t i o n a t 8.0 jiqat N/1 (112 jjg N/1) 0. 31% D e t e c t i o n L i m i t 0.2 ^ g a t N/1 (2.8 / i g N/1) - 124 - R e a g e n t s C o m p l e x i n g R e a g e n t P o t a s s i u m S o d i u m T a r t r a t e ( K N a C 4 H 4 0 6 33 g S o d i u m C i t r a t e HOC ( C O O N a ) ( C H 2 C O O N a ) 2 . 2 H 2 0 24 g D i s t i l l e d W a t e r , q . s . 1000 m l B r i j - 3 5 * ( T e c h n i c i a n N O . T 2 1 - 0 1 1 0 ) 0 . 5 m l P r e p a r a t i o n : D i s s o l v e 33 g o f p o t a s s i u m s o d i u m t a r t r a t e a n d 24 g o f s o d i u m c i t r a t e i n 950 m l o f d i s t i l l e d w a t e r . A d j u s t t h e pH o f t h i s s o l u t i o n t o 5 . 0 w i t h c o n c e n t r a t e d s u l f u r i c a c i d . D i l u t e t o o n e l i t e r w i t h d i s t i l l e d w a t e r . A d d 0 . 5 m l o f B r i j - 3 5 . - 125 - A l k a l i n e Phenol Phenol (C cH cOH) 83 g Sodium Hydroxide, 20% w/v(NaOH) 180 ml D i s t i l l e d Water, q.s. 1000 ml P r e p a r a t i o n : Using a one l i t e r Erlenmeyer f l a s k , d i s s o l v e 83 g of phenol i n 50 ml of d i s t i l l e d water. C a u t i o u s l y add, wh i l e c o o l i n g under tap water, i n smal l increments with a g i t a t i o n , 180 ml of 20% NaOH. D i l u t e to one l i t e r w i t h d i s t i l l e d water. Sodium H y p o c h l o r i t e (Stock) (Technicon No. T01-0114) Any good commercially a v a i l a b l e household b l e a c h having 5.25% a v a i l a b l e c h l o r i n e may be used. Sodium H y p o c h l o r i t e (Working) D i l u t e 2 00 ml of stock sodium h y p o c h l o r i t e t o one l i t e r w ith water. - 126 - Sod i u m N i t r o p r u s s i d e S o d i u m N i t r o p r u s s i d e ( N a 2 F e ( C N ) 5 N 0 . 2 H 2 0 ) 0.5 g D i s t i l l e d W a t e r , q . s . 1000 m l P r e p a r a t i o n : D i s s o l v e 0.5 g o f s o d i u m n i t r o p r o s s i d e i n 900 m l o f d i s t i l l e d w a t e r a n d d i l u t e t o one l i t e r . S t a n d a r d s S t o c k S t a n d a r d A, 5 0 0 0 j p g a t N/1 (70,000 pq N/1) Ammonium S u l f a t e ( N H 4 ) 2 S 0 4 0.3310 g D i s t i l l e d W a t e r , q . s . 1000 m l C h l o r o f o r m 1 m l P r e p a r a t i o n : I n a one l i t e r v o l u m e t r i c f l a s k , d i s s o l v e 0.3310 g o f ammonium s u l f a t e i n 900 m l o f d i s t i l l e d w a t e r . D i l u t e t o v o l u m e w i t h d i s t i l l e d w a t e r . Add 1 m l o f c h l o r o f o r m a s a p r e s e r v a t i v e . - 127 - Stock Standard B, 100 yag a t N/1 (1400 jig N/1) Stock Standard 2 ml D i s t i l l e d Water, q.s. 100 ml P r e p a r a t i o n : D i l u t e 2 ml of stock standard A i n a v o l u m e t r i c f l a s k t o 100 ml w i t h d i s t i l l e d water. Prepare f r e s h d a i l y , Working Standards ml Stock B pg a t N/1 ug N/1 0.2 0.2 2.3 2.0 2.0 28.0 4.0 4.0 56.0 6.0 6.0 84.0 8.0 8.0 112.0 10.0 10.0 140.0 P r e p a r a t i o n : P i p e t t e stock B i n t o a 100 ml v o l u m e t r i c f l a s k . D i l u t e t o 100 ml w i t h d i s t i l l e d water. Prepare f r e s h d a i l y . - 128 - APPENDIX V I I . F i l t e r and D e c h l o r i n a t o r U n i t i n the B i o l o g y B u i l d i n g , U.B.C. Information on the f i l t e r and d e c h l o r i n a t o r u n i t was obtained from Mr. C o l l i n P a r k inson (1979), o f the Zoology Department a t U.B.C. A sketch of the f i l t e r i s shown i n F i g u r e VII-1. A l l dimensions g i v e n are approximate. The f l o w through the f i l t e r i s unknown. A minimum estimate would be 20 0 l/min. The f i l t e r i s b a c k f l u s h e d twice a week f o r about 15 minutes each time. The f i l l i s changed every two to th r e e y e a r s . - 129 - APPENDIX FIGURE VII - 1 . F i l t e r and D e c h l o r i n a t o r Unit, 180 Diff user Si l ica sand Charcoal Crushtd oyster shells Fine gravel Medium gravel Coarse gravel 0.90

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