Spotte 1984 Aquacultural-Engineering

7/28/2019 Spotte 1984 Aquacultural-Engineering

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Aquaculrural Engineering 3 (1984) 207-220

T h e T y p e o f A c t iv a te d C a r b o n D e te r m i n e s H o w M u c hD i s s o l v e d O r g a n i c C a r b o n i s R e m o v e d f ro m A r t if ic ia lS e a w a t e r *

S t e p h e n S p o t te a n d G a r y A d a m sMystic Marinelife Aquarium, Sea Research Foundation Inc.,

Mystic, Connecticut 06355, USA

ABSTRACTFour granular activated carbons (GACs) made of different materials weretested for removal of dissolved organic carbon (DOC) from artificialseawater o f a recirculated aquarium. After 70 days in a continuous flowexperiment, comparative removal data {grams of GAC required to removeI g o]'DOC) were coconut shell (491), hardwood (84.4), anthracite (837)and bone char {383), indicating the superior performance of hardwood.Scanning electron microscopy showed that microbial colonization ofa sample material (hardwood) was slight and occurred exclusively at thesurface. Biological enhancement of GAC was considered to be unimportantas a mechanism for DOC removal.

I N T R O D U C T I O NG r a n u l a r a c t iv a t e d c a r b o n ( G A C ) i s c o m m o n l y u s e d in d ri n k i n g w a t e ra n d w a s t e w a t e r tr e a t m e n t t o r e m o v e o rg a n ic c a r b o n (U S E P A , 1 9 7 3 ;M c C r e a r y a n d S n o e y i n k , 1 9 7 7 ; S u f f e t , 1 9 8 0 ; C o n s t a n t i n e , 1 9 8 2 ;R o b e r t s a n d S u m m e r s , 1 9 8 2 ). S a l e r a n d S l a b b e r t ( 1 9 8 0 ) e v a l u a t e da c t iv a t e d c a r b o n s m a d e o f d i f f e re n t m a t er ia l s to d e t e r m i n e w h i c h w e r em o s t e f f e c t i v e i n w a s t e w a t e r r e c l a m a t i o n . C o m p a r a b l e s t u d i e s i n c l o s e d( r e c i r c u t a t e d ) a q u a r i u m s y s t e m s h a v e n o t b e e n d o n e , d e s p i t e c o n c e r nt h a t s o m e o r g a n i c s a p p e a r i n g in n a t u r a l a n d c a p t iv e w a t e rs a s m e t a b o l i cb y - p r o d u c t s o f a n i m a l s a n d p l a n t s a re to x i c ( S i e b u r t h a n d Je n s e n , 1 9 6 9 ,* Contribution no. 48, Sea Research Foundation Inc.

207Aquacultural Engineering 0144-8609/84/S03.00 Elsevier AppliedPublishers Ltd, England, 1984. Printed in Great Britain Science


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208 S t e p h e n S p o rre . G a ry Ad a m s1970), immunosuppressive (Perlmutter e t a l . , 1973), and limit growthand reproduct ion (Lake, 1967; Yu and Perlmut ter, 1970; Pfuderer e t a l . ,1974: Chen and Martinich, 1975).

METHODS AND MATERIALSFour activated carbons packaged in sealed, waxed paper bags wereobtained from the manufac ture r (Barnebey-Cheney, Columbus, Ohio,USA). Materials and manufacturer's designations were: coconut shell(AC 2143), hardwood (NB L-2175), anthracite coal (302-9342) andsteamed bone char (485-0098). The materials were crushed and sievedthrough a series of standard screens. Grains between 1190 and 2000 umwere retained. Dry masses of the materials were then dete rmined byweighing them in 1 liter lots. Results are given in Table 1.

The source of water was a 113 400 liter recirculated exhibit tank atMystic Marinelife Aquarium filled with modified Segedi-Kelley Medium,an artificial seawater (Spotte, 1979). The exhibit is maintained atambient temperature (~18C) and displays large elasmobranchs andteleosts indigenous to Long Island Sound. Filtration is accomplished bya subgravel filter powered by 18 airlift pumps. The filt rant is a layer ofcrushed oyster shells 30 cm deep. Subgravel filtration is augmented bya 76 cm diameter rapid sand filter. No other treatment or processing isprovided.

The experiment was designed in a continuous flow configuration.Water was pumped from the exhibit through the experimental apparatus(Fig. 1). The influent line consisted of ~6 m Tygon tubing (1.27 cm

T A B L E 1Results of GAC TreatmentC o c o n u t H a r d w o o d A n t h r a c i t e B o n e c h ar

Dry mass of GAC, g 624.3Average flow rate, ml min I 23.69EBVs, 70.43 days 2403DOC removed, g 1-27g GAC/g DOC removed 491

261-0 862.1 765.323.44 23.99 23-542377 2433 23873.09 1.03 2.0084.4 837 383


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2 I0 Stephen Spotte, Gary AdamsI D , 0 .3 c m w a ll t h ic k n e s s ) , o n e e n d o f w h i c h w a s s u b m e r g e d t o t h eb o t t o m o f a n a ir l i ft p u m p . T h e f l o w o f a ir in t h a t a i r l if t w a s s t o p p e d f o rt h e d u r a t i o n o f t h e e x p e r i m e n t . T h e o t h e r e n d w a s i n s er te d t h r o u g h at h r e e - h o l e r u b b e r s t o p p e r in a 1 g a l l o n ( U S ) g la ss b o t t l e t h a t s e rv e d a s a na ir tr a p. B o t h e n d s w e r e c o v e r e d w i t h p l a n k t o n n e t t i n g (6 3 ~ m m e s h ) .T h e a i r tr a p w a s a t a h i g h e r e l e v a t i o n t h a n t h e p u m p a n d f la sk s , w h i c hw e r e a t t h e s a m e l ev e l. T h e s m a l l a m o u n t o f a ir t h a t c o l l e c t e d in t h e n e c ko f t h e b o t t l e w a s r e m o v e d p e r i o d ic a l l y t h r o u g h 7 6 c m o f p o l y e t h y l e n et u b i n g ( 0 . 0 2 c m I D ) a t t a c h e d t o a 5 0 m l s y r in g e . A p i n c h c l a m p a l lo w e dt h e s y r i n g e t o b e d i s c o n n e c t e d t o p u r g e t h e a i r . T h e t h i r d h o l e s e r v e d a st h e e f f l u e n t l in e f r o m t h e a ir tr a p ( i n f l u e n t t o t h e p u m p h e a d s ) . I t w a st h e s a m e s iz e a n d m a t e r i a l a s t h e i n f l u e n t l in e . A m a n i f o l d w a s m a d e b yj o i n i n g t w o n o . 6 n e o p r e n e s t o p p e r s ( o n e t w o - h o l e , t h e o t h e r f o u r - h o l e )w i t h a s p a c e r i n - b e t w e e n a n d t a p i n g t h e s to p p e r s t o g e t h e r . T h e e f f l u e n tl in e f r o m t h e a ir t r a p w a s i n s e r t e d in th e t w o - h o l e s t o p p e r ; th e o t h e rh o l e h e ld a l e n g t h o f p o l y p r o p y l e n e t u b i n g i d e n t i c a l to t h e o n e in t h ea ir t r a p . I t w a s a ls o e q u i p p e d w i t h a p i n c h c l a m p a n d s y r i n g e a n d s e rv e das a so u r c e o f c o n t r o l w a t e r. F o u r s e c ti o n s o f rig id p o l y p r o p y l e n et u b i n g (3 m m I D ) w e r e i n s e r te d i n th e f o u r - h o l e s t o p p e r f o r a t t a c h m e n to f ~ 1 8 0 c m o f C - F le x T u b i n g ( 0 .4 8 c m ID , n u m b e r 6 4 2 4 - 4 5 , C o le -P a r m e r I n s t r u m e n t C o ., C h ic a g o , U S A ) . E a c h l e n g th w a s c o n n e c t e d t oa p u m p h e a d ( M a s t e r f l e x S t a n d a r d P u m p H e a d , m o d e l 7 0 t 5 -2 0 , C o le -P a r m e r I n s t r u m e n t C o . ) . T h e q u a d r u p l e h e a d s w e r e d r iv e n in t a n d e mb y a s in g le p e r i s ta l t ic p u m p ( M a s t e r f l e x ' U n i f i e d ' D r iv e P u m p , m o d e l7 5 2 0 - 3 0 , C o l e - P a r m e r I n s t r u m e n t C o . ) . A l en g th ( ~ 5 0 c m ) o f p ol y-p r o p y l e n e a q u a r i u m t u b i n g ( 0 .3 c m I D ) w a s i n s e r te d in t h e e n d o f e a c hs e c t i o n o f C - F le x T u b i n g a n d c o n n e c t e d t o s t a n d a r d g la ss l a b o r a t o r yt u b i n g ( 0- 3 c m I D ) . T h e g l as s t u b i n g w a s f i r e d a n d e a c h p ie c e w a s b e n ti n t o a n L s h a p e ( 2 3 -5 c m s t r a i g h t t u b i n g p l u s 1.5 c m a f t e r a 9 0 b e n d ) . T h e l e n g t h s o f g l a s s t u b i n g w e r e i n s e r t e d t h r o u g h o n e - h o l en e o p r e n e s t o p p e r s ( n o . 8 ) a n d p l a c e d i n s i d e 1 l it e r g la ss f i lt e r f la s k st h a t s e rv e d a s G A C c o n t a c t o r s . A f t e r w a r d s 1 l it er o f e a c h s ie v ed G A Cw a s w a s h e d w i t h d e i o n i z e d w a t e r a n d p l a c e d in a f la s k . A p lu g o f g la ssw o o l i n s e r t e d in e a c h f la s k a r m f r o m t h e i n s id e p r e v e n t e d p a r ti c le s o fG A C f r o m c o n t a m i n a t i n g t h e s a m p l e s . T h e G A C w a s t h e n s te ri li ze d b ya u t o c l a v i n g t h e f l a sk s at 1 2 0 C a n d 1 0 3 k P a f o r 3 0 r a in . W a t e r f l o w e dt h r o u g h t h e f la s ks , o u t o f t h e a r m s , a n d b a c k t o th e e x h ib i t . T o i n h i b i ta lg ae f r o m g r o w i n g in t h e a p p a r a t u s a n d l e a ch i n g o r g a n ic c o m p o u n d st h e a i r t r a p w a s c o v e r e d w i t h b l a c k p o l y e t h y l e n e , a n d all t u b i n g w a sc o v e r e d w i t h b l a c k e l e c t r ic a l t ap e .


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D i s s o l v e d o r g a n i c c a r b o n r e m o v a l f r o m a r t if ic i a l s e a w a t e r 2 1 1G l a ss w a re w a s w a s h e d s e q u e n t i a l ly i n s o l u t i o n s o f 3% K M n O 4 i n 1 0%

N a O H a n d 1 .5 H C1 in 3% N a.,S O 3, t h e n r i n s e d w i th d i s t i l l e d w a te r t or e m o v e c o n t a m i n a n t o r g a n i c s . I n a d d i t i o n , s a m p l e b o t t l e s a n d g l a s sf i l t e r s w e r e p r e c o m b u s t e d a t 4 5 0 C o v e r n i g h t i n a m u f f l e f u r n a c e .F i l t e r f la sk s t o p p e r s w e r e w r a p p e d in n e w a l u m i n u m f o il t o p r e v e n tp o ss ib le c o n t a m i n a t i o n f r o m t h e n e o p r e n e . O n l y t h e p o l y e t h y l e n et u b i n g w a s n o t t r e a te d , b u t w a t e r f r o m t h e e x h ib i t ta n k w a s a ll o w e dt o f l o w f r e e l y t h r o u g h i t f o r 2 d a y s t o w a s h o u t a n y p a r t i c u l a t e o rs o l u b l e m a t e r i a l .

T h e a p p a r a t u s w a s k e p t i n c o n t i n u o u s o p e r a t i o n f o r 78 d a y s. S a m p l e sf r o m e a c h f l a s k a n d t h e c o n t r o l w e r e c o l l e c t e d o n a l t e r n a t e d a y s a t1 0 0 0 h f o r t h e f ir st 7 0 d a y s . T o c o l l e c t t h e c o n t r o l s a m p l e t h e p i n c hc l a m p w a s r e m o v e d a n d w a t e r w a s d r a w n i n t o a 5 0 m l s y ri n g e a n dd i s c a r d e d . A f t e r w a r d s 5 0 m l w e r e c o l l e c t e d in t h e s y r in g e . S a m p l e s o ft r e a t e d w a t e r w e r e c o l l e c t e d a n d f i lt e r e d d i re c t l y b y h o l d i n g a m e m -b r a n e f i lt e r a p p a r a t u s ( M i ll i p o re C o r p . , B e d f o r d , M a s s a c h u s e t t s, U S A )u n d e r t h e a r m s o f t h e fla sk s. T h e w a t e r w a s f il t e re d t h r o u g h 0 . 3 / a ms i n t e r e d g la ss f i lt e r s ( G e l m a n G l a ss F i l t e r s , t y p e A E , n o . 6 t 6 3 1 , 4 7 r a m ,d i s t r ib u t e d b y V W R S c i en t if ic , B o s t o n , U S A ) . T h e f ir st ~ 1 0 m l o ff il tr a te w e r e f l u s h e d t o w a s t e ; t h e n e x t ~ 5 0 m l w e re c o l le c t e d ina 2 4 0 m l g la ss b o t t le . T h e b o t t l e w a s c a p p e d w i t h n e w a l u m i n u m f o ila n d f r o z en a t - 3 2 C . T h i s p r o c e d u r e c au s es n o lo ss o f T O C ( t o t a lo r g a n ic c a r b o n ) d u r i n g s t o ra g e ( O t s o n e t a l . , 1979) . The g lass f i l t e r sw e r e u s e d o n l y o n c e , a n d t h e f il te r a p p a r a t u s w a s c l e a n e d b e t w e e ns a m p l e s b y f l u s h i n g w i t h d i s ti ll e d w a t e r .

T h e a n a ly t ic a l m e t h o d u s e d t o d e t e r m i n e o r g an i c c a rb o n h a s b e e nd e s c r i b e d p r e v io u s l y ( A d a m s an d S p o t t e , 1 9 8 0, 1 9 8 2 ; S p o t t e a n dA d a m s , 1 9 8 2 ) , e x c e p t t h a t s a m p l e s w e r e p r e fi l te r e d . D i s so l v ed o rg a n i cc a r b o n ( D O C ) w a s m e a s u r e d w i t h a T O C a n a l y ze r ( O c e a n o g r a p h yI n t e r n a t i o n a l C o r p . , C o l l e g e S t a t i o n , T e x a s , U S A ) , u s i n g a n a d a p t a t i o no f t h e w e t o x i d a t i o n m e t h o d o f M e n z el a n d V a c c a r o (1 9 6 4 ) . D e t ai le dp r o c e d u r e s f o r u se o f t h e e q u i p m e n t w e r e g iv e n b y A i re y a n d H o g a n( 1 9 8 0 ) . M o s t o r g a n ic c o m p o u n d s a p p e a r t o b e o x id i z e d c o m p l e t e l y t oC O 2 ( W i l li a m s , 1 9 6 6 ; C o l l in s a n d W i ll ia m s , 1 9 7 7 ) . T h e d e f i n i t i o n o fD O C is a r b i t r a r y , bu t he r e w e de f ine i t a s a ll m a te r i a l t ha t pa s s e dt h r o u g h a 0 - 3 / a m f il te r. T h a w e d s a m p l e s w e r e s h a k e n a n d t ri p l ic a t e5 m l v o l u m e s w e r e p i p e t t e d i n t o 10 m l p r e c o m b u s t e d a m p o u l e s c o n-t a in i n g 0 - 25 g p o t a s s i u m p e r s u l f a t e (K 2 S 2O s ). T h e C O 2 p r o d u c e db y a c i d i f i c a ti o n o f a v a il ab le c a r b o n a t e w a s r e m o v e d b y sp a rg i ng w i t ho x y g e n f o r a m i n i m u m o f 6 r ai n. A m p o u l e s w e r e t h e n s ea le d in


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2 1 2 S t e p h e n S p o t t e , G a r y A d a m sa m a n n e r p r e v e n t in g e n t r y o f a n y c o m b u s t i o n g as es . S e a l e d a m p o u l e sw e r e p l a c e d i n a p r e s s u r e v e s s el a n d o x i d i z e d f o r 3 h a t 1 0 3 C ( _ 5 C ) ,a s m o d i f i e d b y K e r r a n d Q u i n n ( 1 9 7 5 ) f r o m t h e o r ig i na l m e t h o d o fM e n z e l an d V a c c a r o . A f t e r c o o l in g , C O 2 g e n e r a t e d a s a r e a c t i o n p r o d u c tw a s p u r g e d i n t o a n i nf ra r ed a n a l yz e r ( H o r i b a P I R - 2 0 0 0 , O c e a n o g r a p h yI n t e r n a t i o n a l C o r p . ) , a n d t h e o u t p u t w a s i n te g r a te d . T h e C O : c o n c e n t r a -t io n w a s d e t e r m i n e d f r o m a s t a n d a r d c u r v e p r o d u c e d b y o x id i z in gk n o w n a m o u n t s o f p r im a r y s t an d a rd ~ a d e p o t a s s iu m h y d r o g e np h t h a l a t e ( F i s h e r P - 2 4 3 ) d r i e d a t 1 0 5 C f o r a t l e a st 1 8 h . R e a g e n tb l a n k s w e r e m a d e a c c o r d i n g t o s t a n d a r d t e c h n i q u e s , a n d all v a l u e s w e r ec o r r e c t e d f o r o r g a n i c c o m p o u n d s i n t h e r e a g e n t s o r a m p o u l e s .

R E S U L T S8 5 w a t e r s a m p l e s w e r e t a k e n . O n 15 o c c a s i o n s o n e a m p o u l e o f a t ri pl i-c a te s e t b r o k e ; i n o n e c a se t w o a m p o u l e s b r o k e . In f o u r o t h e r i n s t a n c e so n e v a l u e o f a t r i p l ic a t e s e t w a s re j e c t e d b y t h e t -t e s t. T h e d a t a t h u sc o n s is te d o f 2 3 4 D O C m e a s u r e m e n t s . T h e m e a n o f t h e s t a n d ar d d e via -t io n s w a s 0 . 0 4 6 m g D O C l it er -1 a s d e t e r m i n e d f r o m s t a n d a r d d e v i a t i o n so f t h e 6 5 s a m p l e s m e a s u r e d in tr ip l ic a t e. F l o w t h r o u g h t h e fl as k s w a se x p r e ss e d a s e m p t y b e d v o l u m e ( E B V ) , d e f i n e d a s t h e b u l k v o l u m e o fG A C a d d e d t o a f l a s k - in t h is c a s e 1 l it er . A v e r a g e f l o w ra t e s a r es h o w n in T a b l e 1. T h e t o t a l v o l u m e s d e l iv e r e d b y th e f o u r p u m p h e a d sd e v i a t e d l it tl e: m e a n = 2 4 0 0 E B V s , s t a n d a r d d e v i a t i o n = 2 4 -5 E B V sa n d r el a ti v e s t a n d a r d d e v i a t i o n = 1 .0 % .

T h e f o u r s a m p l e s o f G A C d i f f e re d n o t i c e a b l y in a d s o r p t i v e c h a ra c -t e ri s ti c s b o t h in t h e t o t a l m a s s o f D O C a d s o r b e d a n d a d s o r p t i o n r a te( f r a c t i o n a d s o r b e d as a f u n c t i o n o f t im e ) . T h e m a s s o f D O C r e m o v e dr a n g e d f r o m 1 .0 3 g ( a n t h r a c i t e ) t o 3 . 0 9 g ( h a r d w o o d ) , a s s h o w n inT a b l e 1. T h e m a s s o f G A C r e q u i r e d t o r e m o v e 1 g D O C r an g e d f r o m8 4 . 4 g ( h a r d w o o d ) t o 8 3 7 g ( a n t h r a c i te ) , o r a l m o s t a n o r d e r o f m a g n i -t u d e . D i f fe r e n c e s in th e f r a c t i o n o f D O C a d s o r b e d b y e a c h m a t e r i a l a sa f u n c t i o n o f t im e a re i l lu s t ra t ed i n F ig . 2 . H a r d w o o d h a d r e m o v e da m a x i m u m o f 7 3 % o f D O C i n t h e in f lu e n t w a t e r b y d a y 2 . A f t e r w a r d st h e c o n c e n t r a t i o n r e m o v e d d e c l in e d , g r a d u a l l y , to 2 7 % o n d a y 7 0 . I nc o n t r a s t , a n t h r a c i te r e m o v e d a m a x i m u m o f 6 4 % w i t h i n 2 tl o f t h es ta r t o f th e e x p e r i m e n t , b u t b y d a y 4 t h e a m o u n t r e m o v e d h a d d ec l in e dt o 2 9 % a n d f in a l l y t o 7 - 5 % o n d a y 7 0 . B o n e c h a r r e m o v e d a m a x i m u m


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I I I I I I II 2 0 S O 4 0 ,:,0 6 0 7 0

T i m e , dFig. 2 . M assof DOC removed (rag liter -I )as a function o f t ime for 70 days.

o f 4 8 % b y d a y 6 , a nd b y d a y 7 0 t h e a m o u n t h a d d e c l i n e d g r a d u a l l y t o1 2% . U n l i k e t h e o t h e r m a t e r i al s , b o n e c h a r a p p e a r e d t o d e s o r b o rg a n icm a t t e r f o r t h e f ir st d a y , c a u si n g t h e c o n c e n t r a t i o n s o f D O C in t h et r e a t e d e f f l u e n t t o e x c e e d t h e c o n c e n t r a t i o n i n t h e i n f l u e n t . T h ea d s o r p t i o n p a t t e r n o f c o c o n u t s h el l r e s e m b l e d t h a t o f a n t h r ac i te .A m a x i m u m o f 54% o f t h e D O C w a s r e m o v e d o n d a y 1 ; t h e r e a f t e r t h ea m o u n t d e c l i n e d r a p i d l y t o 9 . 6 % o n d a y 3 0 a n d r e m a i n e d e s s e n ti a ll yu n c h a n g e d u n t i l d a y 7 0 .

T h e r a te a t w h i c h a d s o r p t i v e c a p a c i t y d i m i n i s h e d w a s le ss f o r t h em o r e e f f e c t i v e m a t e r ia l s ( h a r d w o o d a n d b o n e c h ar ). H a r d w o o d w a sc l e a rl y s u p e r i o r t o t h e r e s t: a t 4 2 d a y s ~ts p e r f o r m a n c e s ti l l e x c e e d e dt h e p ea k p e r f o r m a n c e o f c o c o n u t a n d a n t h ra c i te ( se e b e l o w ) .


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2 14 Stephen Spot te , Gary AdamsDISCUSSION

Maximum DOC removal by coconut shell and hardwood occurred atday 1.42, that of anthracite at day 0.65 and bone char at day 4.42.Such early peak performances were expected. Adsorption rate isa mass transfer process, limited by factors that control diffusion.Foremost of these is the adsorbate concentration of the untreatedinfluent. Before adsorption from a liquid to a solid phase can occura film of liquid must form on the surfaces of the adsorbent. Thegreatest adsorption rate takes place immedia tely after 'wetting' becausethe concentration gradient for diffusion is steepest. Adsorption ratediminishes rapidly as adsorbate concentrations in the two phases(liquid and solid) approach steady state.

In the 70 days of the sampling period 8.5% of the volume of theexhibit was filtered through the four flasks and returned to the watersystem. In this period 7.39 g DOC were removed, representing 2.1%DOC in the exhibit water at any time. The fact that treated effluentwas returning to the aquarium exhibit where it comprised a tinyfraction of the largely untreated reservoir did not affect the results, asillustrated by the small variation in the DOC concentration of thecontrol (untreated) water. Control water DOC was measured 17 timesin triplicate and values ranged from 3.14 to 3.53 mg liter ~. The meanconcentra tion was 3.30ra g liter 1 (standard deviat ion= 0-097 mgliter -1, relative standard deviation = 2.9%). When the data are plotted(Fig. 3) they illustrate tile remarkable capacity of tile biological filterfor degradation of organic mat te r (i.e. DOC does not increase signifi-cantly with time).Under certain conditions the microbiological films that form on GACgrains measurably enhance TOC reduction in wastewater (Maqsood andBenedek, 1977; Ying and Weber, 1979; Lowry and Burkhead, 1980;Lin, 1983; Li and DiGiano, 1983). The usual explanation for why thishappens is the large surface area on GAC grains for attachment andgrowth of microorganisms (American Water Works Association, 1981),but recent research indicates that surface area is not the determiningfactor. Bancroft e t a l . (1983) studied removal of TOC from wastewater.They found no statistical difference in its microbial removal on GACcompared with silica sand. The latter material is non-porous and hasa much smaller surface area. Peel and Benedek (1983) reported that the


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Dissolved organic carbon remova? ?om arrihciai seawater 215

]

Fig. 3.a t t r i b u t a b l e t o m i n e r a l i z a t io n o f o rg a n i c m a t t e r b y b a c t e r ia in t h e f i lt e r b ed .

. . . . ~ ' ,I 0 L.~l) ;~) l ~ - ~ . ) 6 0 (}Time, d

Plot of D OC conce ntrat ion of the co ntrol water . The sm all variat ion is

p r e s e n c e o f m i c r o o r g a n i s m s in G A C b e d s h a d n o e f f e c t o n T O C re d u c -t i o n in s i m u l a t e d w a s t e w a t e r . T h e y s u g g e s t e d t h a t b i o lo g i c a l e n h a n c e -m e n t is l i m i t e d t o s i t u a t i o n s in w h i c h t h e o r g a n i c c a r b o n is b i o d e g r a d -a b l e a n d s u f f i c i e n t o x y g e n is a v a il a bl e . S c a n n i n g e l e c t r o n m i c r o s c o p y( S E M ) w a s u s e d t o d e m o n s t r a t e h o w s p a rs e ly t h e s u r fa c e s o f G A Cg r ai n s w e r e p o p u l a t e d w i t h m i c r o o r g a n i s m s , a n d th a t th e i n te r n a l p o r e sw e r e d e v o i d o f ce lls . W e s u b j e c t e d o n e o f o u r t e s t m a t e r ia l s ( h a r d w o o d )t o S E M o n d a y s 0 , 4 9 a n d 7 8 ( F i g s 4 t h r o u g h 7 ). V i s i b le m i c r o o r g a n i s m sc o l o n i z e d o n l y t h e s u r f a ce s o f t h e m a t e ri a l. N o b a c t e r ia o r p r o t o z o a n sw e r e f o u n d i n s id e t h e u s e d G A C , d e s p i t e it s e x t e n s i v e i n t e rn a l p o r es t r u c t u r e .

P h y s i c a l a d s o r p t i o n a n d b i o l o g ic a l d e g r a d a t i o n o c c u r s i m u l t a n e o u s l yin G A C b e d s , a n d t h e i r s p e c i f ic e f f e c t s a re d i f f i c u l t t o d i st in g u i s hw i t h o u t i n f lu e n c i n g p r o c e s s c o n d i t i o n s ( P e e l a n d B e n e d e k , 1 9 8 3) . W em a d e n o a t t e m p t t o d e t e r m i n e h o w m u c h D O C r e m o v a l w as r e l at edd i r e c t l y t o m i c r o b i a l a c t i v i ty . T h e d a t a s u g g e st th a t r e m o v a l o f D O Cu n d e r c o n d i t i o n s o f o u r e x p e r i m e n t w a s e x c l u s iv e l y a p h y s i c a l a d s o rp -t io n p r o c e s s . B i o lo g i ca l e n h a n c e m e n t d o e s n o t a p p e a r t o h a ve b e e na f a c to r . O u r u n t r e a t e d i n f l u e n t w a s p o s s i b l y n u t r i e n t- l im i t e d , h y p o x i c ,o r b o t h , w h i c h c o u l d a c c o u n t f o r th e u n e x p e c t e d l y l o w d e gr ee o fc o l o n i z a t i o n .

A m o r e l ik e l y e x p l a n a t i o n is th e v i g o r o u s a c t i v i t y o f t h e b i o l o g ic a lf il te r , w h i c h m a y h av e r e d u c e d t h e c o n c e n t r a t i o n o f b i o d e g a d a b l e


10/14

2 1 6 S t e p h e n S p o t t e , G a r y A d a r n s

F i g, 4 . S E M o f u n u s e d h a r d w o o d G A C . L o o s e m a t e r ia l is s u r f ac e 'f in e s ' , ( 5 2 5 x .)

F ig . 5 . S E M o f t il e s u r f ac e o f u s e d h a r d w o o d G A C a t d a y 4 9 . ( 5 2 0 x .)


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D i s s o l v e d o r g a n i c c a r b o n r e m o v a l f , o m a r r if ic i a i s e a w a t e r 2 1 7

Fig , 6 . SEM o f the surface o f used hard w oo d GAC at day 78. Visible rn icro-o rgan i sms inc lude cocc i , rods and s t a lked bac te r i a ( C a u l o b a c t e r - l i k e ) . some appear -ing to be embedded in ext racel lu lar mater ia l or a t tached by i t . Not v is ib le in th ispho tomicrograph bu t seen m o the rs were choanof l age l t a t es and smal l r . e s t a t e

am oeba e , wh ich p rob ab ly consu me bac te r ia , t 2350 .~. I

D O C b e f o r e t h e i n f l u e n t w a t e r r e a c h e d t h e G A C f la sk s . T h e e x t e n t o fa n y s u c h a c t i v i t y w a s n o t d i s c e r n i b l e o n a s h o r t - t e r m b a sis , a s w el e a r n e d f r o m a b r ie f , a n c i l l a r y e x p e r i m e n t . W a t e r w a s s a m p l e d a t f iv el o c a t i o n s j u s t a b o v e t h e f i l t e r b e d a n d in f iv e o f t h e a i r l if t s ( i . e . b e l o wt h e f i l t e r b e d ) t o d e t e r m h l e it" t h e d e c r e a s e in D O C c o n c e n t r a t i o n a c ro s st il e l a y e r o f c r u s h e d o y s t e r s h e ll s w a s s ig n i f ic a n t . E a c h s a m p l e w a sa n a l y z e d in t r ip l i c a t e b y t h e p r o c e d u r e s d e s c r i b e d p r e v i o u s l y . 10m e a s u r e m e n t s w e r e m a d e a b o v e ti l e b e d a n d 13 b e l o w i t . T h e D O Cc o n c e n t r a t i o n s a v e r a g ed 1 -9 05 m g l i te r -~ ( s t a n d a r d d e v i a t i o n = 0 . 1 3 4m g l i te r - 1) a n d 1 - 8 2 2 m g l i te r < ( s t a n d a r d d e v i a t i o n = 0 . 0 9 6 m g l i te r -~ ) .r e s p e c t i v e l y . A t a 0 . 0 5 l e v el o f s ig n i f ic a n c e w e c a n n o t c o n c l u d e t h a t t h eo b s e r v e d d e c r e a s e is n o t d u e t o c h a n c e .


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2 18 S t e p h e n S p o t r e , G a r y A d a m s

Fig. 7. SEM of the interior of used hardwood GAC at day 78. Note that the poresare perfectly clean and devoid of microorganisms, indicating that colonization

occurs primarily on external surfaces. (223 x .)

AC KNOWLE DGEM ENTSPatricia M. Bubucis and Michael B. McHone provided technical assist-ance, and Joseph T. O'Neill and Trish LaPointe drew Figs 1, 2 and 3.James W. Atz, Joseph P. Bidwell, John D. Buck and Lee C. Eagletonreviewed the manuscript.

REFERENCES

Adams, G. & Spotte, S. (1980). Effects of tertiary methods on total organic carbonremoval in saline, closed-system marine mammal pools. A m . J . V e t . R e s . , 41,1470-4.Adams, G. & Spottc, S. (1982) Removal of total organic carbon from marinemammal pool water by polymeric resins. A m . J . V e t . R e x . . 43,919-2l.


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Dissolved organic carbon removal from artificial seawater 219Airey , D. & Hogan , M. (1980) . Methods fo r the de te rmina t ion o f d i sso lved and

part icula te organic carbon in marine samples . Rpt. 127, Division of Fisheries andOceanography, CSIRO, Cronulla , AustraUa.

Am erican Water Works Asso cia t ion (1981) . An assessment of m icrobia l ac t iv i ty onGAC. J. Am. Water Works Assoc., 7 3 , 4 4 7 - 5 4 .Bancrof t , K. , Maloney, S . W. , McElhaney, J . , Suffe t , I . H. & Pipes , W. O. (1983) .

Assessment o f bac te r ia l g rowth and to ta l o rgan ic ca rbon remova l on g ranu la rac t iva ted ca rbon con tac to rs . AppL Environ. Microbiol., 4 6 , 6 8 3 - 8 .

Bouw er , E . J . & M cCar ty , P. L . (1982) . Rem ova l o f trace ch lo r ina ted o rgan iccompounds by ac t iva ted ca rbon and fb~ed- f i lm bac te r ia . Environ. Sci. Technol.,1 6 , 8 3 6 - 4 3 .

Ch e n , L -C . & M a r tin ic h , R . L . ( t 9 7 5 ) . P h e ro mo n a l s t im u la t io n a n d me ta b o l i t einh ib i t ion o f ovu la t ion in the zebra f i sh , Brachydanio rerio. Fish. Bull. (NOAA),7 3 , 8 8 9 - 9 4 .

Col l ins , K. J . & Wil l iams , P . J . LeB. (1977) . An au tomat ic pho tochemica l me thodfor the determinat ion of d issolved organic carbon in sea and es tuar ine waters .Mar. Chem., 5 , 1 2 3 - 4 1 .

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Lowry , J . D. & Burkhead , C. E . (1980) . The ro le o f adsorp t ion in b io log ica l lye x te n d e d a c t iv a t e d c a rb o n c o lu mn s . J. WaterPollut. Contr. Fed., 5 2 , 3 8 9 - 9 8 .M aqsood , R. & B enedek , A. (1977) . Low - tempera tu re o rgan ic remova l and den t r i-

f ica t ion in ac t iva ted ca rbon co lum ns . J . Water Pollut. Contr. Fed., 4 9 , 2 1 0 7 -1 7 .McCreary , J . J . & Sn oe yin k, V. L . (1977) . G ranular ac t ivated carbo n in w ater

t r e a tme n t . J. Am. Water Works Assoc., 6 9 , 4 3 7 - 4 4 .Menzel, D. W . & Vaccaro , R. W. (1964) . The m easu rem ent o f dissolved and par t icu-

la te carbon in seawater . Limnol. Oceanogr., 9 , 138-42 .O tsotu R., W illiams, D. T. , B othw ell, P. D., McCullough, R. S. & Ta te, R. A. (197 9).Effects of sam pling, sh ipping, and s torage on to ta l organic carbo n levels in water

samples. Bull. Environ. Contam. Toxicol., 2 3 , 3 1 1 -1 8 .Peel, R . G. & B enedek , A. (1983) . Biode grada t ion and adsorp t ion wi th in ac tiva ted

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220 Stephen Spor te , Gary Adam sPerlmutter , A. , Sarot , D. A. , Yu, M-L. Fi lazzola , R. J . & Seeley , R. J . (1973) . The

e f f e c t o f c ro wd in g o n th e immu n e r e sp o n se o f t h e b lu e g o u ra mi , Trichogastertr ichoptenls , to infect ious pancreat ic necrosis ( IPN) virus . Life Sci.. 1 3 , 3 6 3 - 7 5 .

Pfud erer , P ., W ill iams, P . & Francis , A . A. (197 4) . Par t ia l pu r if ica t io n of the crow d-ing fac tor in Carassius auratus an d Cyprinus carpio. J. Exp. Zo ol., 1 8 7 , 3 7 5 - 8 2 .Rob er t s , P . V. & Sum mers , R. S . (1982) . P e r fo rm ance o f g ranu lar ac t iva ted ca rbon

for to ta l organic carbon removal . J. Am . W ater Works Assoc. , 74, 113-18.Sa le r, A. & S labber t, J . L . (1980) . A p re l im inary com par ison be tween va r ious

granu la r act ive ca rbons fo r w a te r rec lam at ion . Water SA . 6, 196-203.S iebur th , J . M cN .& Jense n , A. (1969) . S tud ies on a lgal subs tances in the sea. II .

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Spo t te , S . & Adams, G. (1982) . E f fec t o f two po lymer ic res ins on to ta l o rgan icca rbon (TO C) in rec i rcu la ted seawate r. Aquacul ture , 2 9 , 1 5 9 - 6 4 .

Suf fe t , I . H. (1980) . An eva lua t ion o f ac t iva ted ca rbon fo r d r ink ing wa te r t rea tm en t :a Na t io n a l Ac a d e m y o f S c i en c e r e p o r t . J . Am . Water Works Asso c. , 7 2 , 4 1 -5 0 .

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W ill iams, P . J . LeB. (196 6) . The w et ox ida t io n o f organic m atte r in seawater .Limnol. Oceanogr. , 1 2 , 2 9 2 - 6 .Ying, W -C. & W eber , W. J . J r . (1979) . Bio-ph ysicochem ical ads orp t ion m ode l

sy s t e ms fo r wa s t e wa te r t r e a tm e n t . J . WaterPollut. Co ntr. Fed . , 5 1 , 2 6 6 1 -7 7 .Yu , M-L . & Per lmut te r , A. (1970) . Growth inh ib i t ing fac to rs in the zebra f i sh ,Brachydanio rerio a n d th e b lu e g o u ra mi , Trichogaster m'choptems. Growth,34 , 153-75 .

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