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Wat.Sci.Tech.

Vol. 15,

Copenhagen,

Printed in Great Britain.

pp.I-IOI.

Copyright © 1983

0273-1223/83

$0.00 +

.50

IAWPRC/Pergamon Press Ltd.

ANAEROBIC TREATMENT OF W ASTEW ATER IN FIXED FILM REACTORS - A LITERATURE REVIEW Mogens Henze an.d Poul Harremoes Department of Environmental Engineering, Technical University of Denmark, DK-2800 Lyngby, Denmark AB S T RACT A r e v i ew of a n a e r o b i c t r e a tment of wa s tewa t e r i n f ix e d f i lm r e a c to r s i s pr e s ent ed . T h e b io c h em i s try a n d m i c rob i o lo g y i s d i s c u s s ed , w i th empha s i s l a i d on ki n e t i c p a r ame te r s l i ke g r owth c o n s tant s , s ub s t r a t e remova l r a t e s and g r owth y i e l d s . The i n f l ue n c e o f tempe rature , tox ic sub s ta nc e s , n u t r i e n t s and pH upon p r o c e s s p e r f o rmance i s eva l u a t e d . The kine t i c s o f anaerob ic b i o f i lm s i s d i s c u s s e d . T h e e f f e c t o f d i f f u ­ s i ona l l im i t a t i o n and me thane gene r a t i o n w i t h i n the b io f i lm a r e im­ portant f a c t o r s not s tu d i e d y e t . The v a r i o u s r e a c tor type s and p r o ­ c e s s c o n f i g ur a t i o n s a r e c o mmented upon . Mo s t s tud i e s o f an ae r o b ic proce s s e s unt i l now have b e e n w i th f ixed b e d r e a c t o r s , and w i t h s o ­ lub l e s ub s t r a te s . The de s ign o f r e a c t o r s s h o u l d b e b a s e d upon b i o f i lm a r e a o r b i oma s s i n the r e a c t o r s . A t pre s e n t b io f i lm a r e a c a n n o t b e u s ed f o r de s i gn due to lack o f inve s t ig a t i o n s on a n a e rob ic b i o f i lm kine t i c s . An a e r o b i c f i xed f i lm proc e s s e s c an be u s ed f o r indu s t r i a l w a s t e s c o n t a i n ing o r g a n i c ma t t e r a t t i o n s . T r e a tmen t o f mun ic i p a l wa s tewa t e r i s a t fe a s ib l e , but the d eve l o pmen t of new e f fe c t ive be l i eved t o change th i s i n the n e a r future .

a lmo s t a l l type s o f r e a s on a b l e c o n c e n t r a ­ pre s e n t n o t r e g arded type s o f r ea c to r s i s

1. INTRODUC T I ON Th i s r e v i ew h a s b e e n made f o r the IAWP RC - s pe c i a l i z e d s em i n a r on an a e ­ ob ic t r e a tment o f w a s tewa t e r i n f ixed f i lm r e a c t o r s he id in Copen­ hagen , June 1982 . The ma j o r i d e a ha s b e e n to e s tab l i s h a f r amewo rk f o r the d i s c u s s ion dur i ng the s em in a r . Empha s i s has been l a i d upon b r i n g i n g the r e v i ew up- t o - d a t e , r a th e r than to make it e x te n s ive . Th i s might be one o f the r e a s o n s why many a u tho r s may n o t f ind the i r v a luab l e c on tr ib u t i o n s to the a n a e r ob ic l i te r a ture quo ted . The pape r s p r e s ented at the s em i n ar have b e e n inc luded in th i s rev i ew i n o r d e r t o e s t ab l i s h the c onnec t i o n b e twee n the o r i g i n a l pape r s pre s ented a t t h e s e m i n a r a n d t h e f o r e g o i n g l i te r a tu r e .

1

2

M.

HENZE

and P.

HARREMOE S

2 . WAS T EWATER V S . S L UDGE TREATMENT In anaerob i c s ludge t r e a tment the s o l id s r e t e n t i o n t ime, ex, and the hyd rau l ic re te n t i o n t ime, e, a r e a lmo s t iden t i c a l . The r a t i o eX/e m i g ht b e inc r e a s ed to 1.5 - 2 , due to w i th d rawa l o f d i g e s te r supe r n a ­ tan t . I n a n a e r o b i c wa s tewa t e r t r e a tment, howeve r , the r a t i o b e tween s o l id s r e t e n t i o n t ime and hydrau l i c r e t e n t i o n t ime c a n b e i nc r e a s ed to 10 - 10 0 . Th i s redu c e s the r e a c t o r volume c o n s i d e r a b l y and mak e s an a e rob i c w a s tewa t e r t r e a tment e c onom i c a lly i n t e r e s t ing a s c ompa red to a e rob i c proc e s s e s . Fo r aerob i c proc e s s e s the c o s t o f a e r a t i o n i n c re a s e s w i th i nc r e a s ed c o n c e n t r a t ion o f o r g a n i c ma t t e r , a n d above s ome 5 - 10 kg COD/m 3 the s y s tem b e c om e s oxygen t r a n s f e r lim i ted, wh i c h r e s u l t s in i nc r e a s e d hydrau l i c r e t e n t i o n t ime in order to e n s ure s u ffi c i e n t oxygen supp l y to the p r o c e s s . Fo r s u ch indu s t r i a l wa s t e s , an a e r o b i c t r e a tment h a s long

been economically attractive.

The development o f

processes

wit h h igh er volume t r i c lo ad capac i ty (e xpa nded and f lu i d i z e d b e d s and s ludge b l anke t r e ac t o r s ) h ave gr adually inc r e a s e d t h e i n t e re s t i n t r e a t ing more d i lute wa s t e s i n anaerob i c r e a c to r s . Re c e n t l y th i s ha s l e d t o i nve s t ig a t i o n s i n t r e a tmen t o f mun i c i p a l wa s tewa ter i n anaerob i c r e a c to r s . The borde r l i n e b e tween s ludge a n d w a s tewater i s i ll defined, b u t i n the p re s en t work wa s tewa t e r h a s b e e n de f i ned a s a w a s t e , whe re the majo r part of the o r g a n i c s are s o l ub l e (e .g . s o lub i li ty index > 2 0 %). "Wa s tewate r " w i t h a l o w p e r c e n t a ge o f s o lub l e o r g a n i c s c an b e t r e a t ­ ed phy s i c ally to g ive h i gh t r e a tmen t e ff i c ie n c i e s fo r organ i c s w i th­ out any b i o lo g i c a l pro c e s s involved , whe r e a s ma i n ly s o luble wa s te s mu s t b e t r e a t e d b io l o g i c a l ly (o r chem i c a l l y ), i f a re a s onab l e r emoval e f f i c i e n c y is a imed at.

3

A l i t e r a t u r e r ev i ew

3. BI OCHEMI STRY AND MI C RO BI OLOGY The b i oc hemi s try and m i c r ob i o l o g y o f a n ae rob i c proce s s e s is muc h more complic a t e d than that of a e r ob i c o ne s . T h i s is a r e s u l t of the many pathway s ava i l ab l e f o r an anae rob i c c ommu n i ty . T he p a hthways and m i ­ c r o o r g an i sm s r e spon s i b l e f o r t h e r e a c t i o n s a r e n o t k nown i n g r e a t deta i l , but du r i ng t h e l a s t 10 - 15 y e a r s a b r o ad out l in e o f t h e p r o ­ c e s s e s h a s b e e n e s tab l i s he d a s d e s c r i bed by a numb e r o f inve s t i g a t o r s (Mc C a r ty 1964, Lawren c e and Mc C a r ty 1969, To e r ie n 1969, Ba l c h e t a l . 197 9, Ze iku s 197 7). 3.1 Mic rob i o l o gy Basically the anaerobic degradation is performed by 2 groups of bacteria, the a c id produ c ing and the me thane produ c ing b a c te r i a . The s e two groups can b e subd ivided into two g roups e a c h, as shown i n t ab l e 3.1. It mu s t b e ment i on e d that f o r one o f the g roup s , t he b a c t e r i a ab l e t o produ c e butyr i c and propion ic ac id, spe c i e s h ave n o t b e e n i s o l a te d in p u r e cu l ­ ture, b u t o n l y i n c o - c u l tu r e , Mc I ne r y e t a l . (197 9) a n d Boone a n d Bryant (1980 ). The s p e c i f i c s pe c i e s o f anaerob i c b ac te r i a have b e e n d i s cu s s e d b y Ze hnder (197 8) a n d (1981), Ba l c h e t a l . (197 9), and o t h e r s .

Tab l e 3.1. Ac id produc ing bac t e r i a

Ma jo r g roups o f an ae rob i c m i c r o o r g a n i sm s Ac id f ormi n g b a c t e r i a a c id ) Ac e to g e n i c b a c te r i a

Me thane produ c i n g bac t e r i a

(but y r i c a n d prop i o n i c

(ac e t i c a c i d a n d hydrogen)

Ac e t o c l a s t ic me t hane b a c t e r i a Me tha n e b a c t e r i a

(ac e toph i li c )

(hydrogenoph i l ic )

Rega rd ing s p e c i f i c b a c t e r i a i n a na e r o b i c r e a c to r s , t h e r e h a s b e e n few inve s t ig a t i on s . Haku l i ne n a n d S a l k inoja - S a l o n e n (198lb ) h a v e s tu ­ d i e d the m i c rob i o l ogy o f an a na e r o b i c f l u id i z ed b e d r e a c t o r . N o metha­ nogen s were i s o l a t e d whi c h may b e due to a l ow s o li d s r e t e n t ion t ime whe r e o n l y a c i d produ c i n g b a c t e r i a c a n e x i s t . P o l et a l . (1982 ) s tu d i e d the granu l e s o f s ludge b l ank e t r e a c t o r s and f o u n d t ha t t h e y c o n s i s te d of e i t he r mu l t i c e l l u l a r f i l amen t s o f r o d s h aped o r g a n i sm s , o r s h o r t mu l ­ t i c e l lular rod - s haped f r agme n t s c on s i s t i n g o f about 4 c e l l s e a c h . Bo th type s were po s s ib l y Me t ha n o t hr i x s o ehngen i i . A s im i l a r rod - s haped or­ gan i sm wa s s tud ied by C o l v i n e t a l . (197 9) 3.2 S t e ps o f r e a c t i o n The anae rob i c me tabolism o f a c omp l e x s ub s t r a te , i n c l u d i n g s u s pended orga n i c ma t t e r , c a n be r e g arded a s a t hr e e s te p p r o c e s s : 1. s te p :

Hydro l y s i s o f s u s pended o r g a n i c s and s o lub l e o r g a ­ n i c s o f hi g h mo l e c u l a r we i g h t . 2 . s te p : D e g r ad a t ion o f sma l l o r g a n i c mo l e c u l e s to v a r i o u s vola t i l e f atty a c i d s , u l t imate ly a c e t i c a c i d . 3 . s t e p : P r o du c t i o n o f me t h a n e , p r ima r i ly f rom a c e t i c a c i d b u t a l s o f rom hyd r o g e n a n d c a rbon d io x i d e .

4

M.

HEN Z E and P. HARREMOE S

Gu j e r and Zehnder (1982 ) ope r a t e s w i th a more d e t a i l e d d e s c r i p ti o n w i t h 6 s te ps whe r e s ome o f the 3 s teps a b o v e a r e s ub d i v i d e d . O f the 3 s te p s , the s e cond one i s r a th e r qu i c k , wh i l e the two other s are s l ow. T h i s a c c oun t s f o r many i n s t ab i l i ty p r o b l em s e n c ount e r e d in anae rob i c proc e s s e s . Ba s i c l y, howeve r , the an ae rob i c p r o c e s s e s a r e n o t m o r e un s t ab l e than a e r ob i c . One o f the re a s on s w h y th i s i s a rathe r rare v i ew, i s that e n g i n e e r ing d e s i g n prac ti s e f o r anae r ob i c proc e s s e s through the ye a r s h ave b e e n ope r a ting w i th r a th e r s mal l s a f e t y f a c t o r s and a very poo r pro c e s s c o n t r o l . H ydr o l ys i s o f organ i c matter i s a r a th e r s l ow pro c e s s b rought about b y e xtra c e l l u l a r e n z yme s . Fa c t o r s l ike pH and c e l l r e s i d e n c e time p l ay an impo r ta n t ro l e w i th re s pe c t to r e a c t io n r a t e , Ve r s tr ae te e t a l . (1981). L i pid s a r e hydro l y z e d v e r y s l ow l y , w i th t h e r e s u l t that the hydro ly s i s s te p might be ove r a l l (inc l u d i n g methane produ c ti o n ) rate l im i t ing f o r wa s t e s cont a i n in g c o n s i d e r ab l e amount o f l ip id s , and other s low ly hyd ro ly z ing c ompound s , l i ke e .g . pigge ry was te , Kennedy and van d e n Be rg (1982 a ). The type o f l ipid appa r e n t l y p l ay s a r o l e , a s the d e g r a d a t i o n o f nonpo l a r l i pid s in a n a erob i c pro ce s s es s e e ms to b e c o n s i d e r ab l y s lowe r than the d e g r a d a t i o n of po l ar s u b­ s ta n ce s (Te rmo f i l 1981). Ea s tman and Fe rgu s o n (1981) have demon s tr a t e d t h a t in a s e p ar ate ac i d produc ing r e a c t o r , t h e hydro l y s i s i s a lway s the r a te l im i t ing s te p . Gu j e r and Ze hnde r (1982 ) e s t imate s the hydro l y s i s r a te in a c o mb i ne d anaerob i c r e a c tor to be 0 .3 d - l a t 35 0 C , wh i c h i s i n s trong c o n t r as t to the rate (3 d-l) found by Ea s tma n and Fe rgu s o n (1981) in a s e p ar a­ te a c i d produc ing r e a c t o r , and wh i c h i nd i c a t e s tha t hydro ly s i s i s n o t the r a te l im i t i n g s te p in t h e c omb i ned a n a e r o b i c proc e s s s tu d i e d by Gu j e r and Zehnde r . Ac id produ c t i o n r e s u l t s in f o rma tion o f a c e ti c a c i d or in c a s e o f in­ s t ab i l ity, the h ighe r f atty ac i d s s u c h as propi o n i c , buty r i c , i s o­ butyr i c , va l e r i c - and i s o- va l e r i c a c id. A g en e r a l out l in e o f the me tab o l i c p a thwa y s o f the ac id produc ing b a c te r i a is s hown in figure 3.1. I n a s tab l e a n a e rob i c pro c e s s the c on c e n t r a t i o n o f f at ty aci d s i s f a i r ly l ow (0 .1- 0 .3 kg H Ac /ms). I n c r e a s e d c o n c e n t r a t i o n s a r e i n ­ d i c a t i o n s o f l o ad var i a t i o n s o r a pro c e s s o pe r a t ing n e a r i ts max i mu m l o a d (w i t h a m i n imum s a f ety f a c t o r ). Dur ing s t a r t-up o f the anaerobic proc e s s the vo l a t i l e a c i d c o n c e n t r a t ion s h o u l d b e k e p t r e a s onab l y l ow 1, 0 - 1, 5 kg H Ac /ms) and c an be u s ed to c o n t r o l the s low l o ad ing in­ « c r e a s e a l l owed - see c h a pt e r 7. Mo s e y (1982 ) and (1982 a ) po s tu l a t e s in h i s mod e l f o r s h o r t - c h a i n vo l a t i l e a c id s , th a t hydrogen p a r t i al pre s su r e (o r redox po te n t i a l ) r e gu l a t e s the produc t io n o f the var i o u s ac i d s . For d i g e s t e r s o pe r a t ing a t v e r y s h o r t s o l id s r e t e n t ion time the c o n c e n t r a t ion o f propi o n i c ac id and hydrogen i s i nc r e a s ed . Th i s f i t s we l l into the g e n e r a l pi c tu r e , and c a n al s o exp l a in the i n c r e a s e d pro pi o n i c a c i d c o n c e n t r a t i o n s under u n s t e a dy s t a te o r varying l o ad condi tion s . The u s e o f pro pi o n i c a c id a s an ind i c a t o r o f in s tab i l i ty have b e e n d i s cu s s e d by Ke nnedy and van den Be rg (1982 a ) and T e r mofi l (1981) and i s a g e ne r a l l y a c c e pted proc e s s c o n t r o l p a r ame te r , al l ­ through n o t u s ed muc h in pr a c t i s e . T h e ac id produ c t i o n r a te i s h i gh a s c ompa r e d t o the me thane production r a t e , wh i c h m e a n s that a sudden inc r e a s e in e a s i l y d e g r a d able (so lu bl e ) o r g a n i c s w i l l r e s u l t i n inc r e a s e d a c id produc t i on w i th s ub s e quent ac­ c umu l a tion o f the a c i d s . Th i s might inhib i t the next s te p of the pro­ c e s s , the methane step. P a r a l l e l to the a c id produ c t io n , ammo n i a i s

5

A l i t e r a t u r e r ev i ew

LIPIDS

PROTEINS

1

CARBOHYDRATES

Amino acid

Long chain folly acids

Formic acid

Fi gure 3. 1. Rea c t i o n s p e r f o rmed by a c id produc ing b a c t e r i a . Only ma j o r route s i nd i c a t e d (b a s e d on S t a f f o r d (1980 ), S i xt (197 9), Mo s e y (1982 ) and o t he r s ).

r e l ea s ed by the d e g r ad a t i on o f pro t e i n s and am ino ac i d s (Mc C r e ady 197 8 ) . The a mmon i a - c on c e n t r a t i o n s t h�s e s tabli s hed w i ll g e n e r a lly n o t be o f a magn itude t h a t will inh ib i t t he a na e rob i c p r o c e s s b u t f o r n i t r o g en rich wastes t r ea t ed in h i gh ly lo aded proc e s s e s , ammo n i a i n hib i t ion c ould o c cur . Methane produc t i o n i s a s low p r o c e s s , i n g e n e r a l the r a t e - lim i t ing s t e p o f anaer o b i c deg r ad a t i o n . Me t hane i s produc ed f r om a c e t ic a c id or f r om hyd r o g en and c a r bon d i o x i d e . About one t hi rd o f t he methane ha s i t s or igin i n mo l ec u la r hyd rogen (Gu j e r a n d Zehn d e r 1982 , Jer i s a n d Mc C a r ty 1965, Smith and Hay, 1966). Small amoun t s o f me thane c a n be produ c ed fro m methan o l (Smith a n d Mah 197 8) and f o rm i c a c i d , but the s e r e a c t i o n s have l i ttl e pra c t i c a l impo r tanc e . Fi gure 3.2 d e p i c t s the ma in proc e s s e s per for med by metha n e produ c i n g b a c te r i a.

M.

6

HENZE

and P.

I Ethanol

Acetic

External

Figure 3. 2 .

acid

HARREMOE S

I Formic acid

I Methanol

production (from outside this figure)

Re ac t i o n s pe r f ormed by me thanog e n i c b ac t e r i a (b as ed o n S ix t (1979), S t af f o r d (198 0 ), Zehnde r (1978 ), Mo s ey (198 2 ) and othe r s ).

The b ac t e r i a produ c i n g methane f rom hydrogen and c arbon d io x i d e are f as t g r owing o n e s as c omp ared w i th the ac e t i c ac id u t ili z ing b a c t e ­ r i a. The f o rme r are in e v e r y r e s p e c t t h e pr imadonnas o f an ae rob ic d i ge s t io n . Whe n c o nd i t i o n s ar e s u c h tha t t hey p r o li f e r a�e , all othe r bac t e r i al s p e c i e s n ec e s s ary f o r the anae r ob i c d e gr ad at i o n w i ll als o thr i ve . Th i s doe s n o t n e c e s s ar i ly me an that the methan e produc ing re ac ti on is r ate lim i t i n g , the hyd r o ly s i s may h ave that r o le (Gu j e r an d Zehnder 198 2 ).

7

A l i t e r a t u r e r ev i ew

3.3 Growth c o n s t a n t s o f anaerob i c b a c te r i a The two domi nat ing b a c t e ri a l s te p s in a n a e rob i c me taboli sm h a v e very d i ffe rent growth c o n s tant s . Table 3.2 - 3.4 summari z e s s ome li te ra ture data on - max imum s p e c ific growth rat e , - y i e ld c o e ffi c i e n t , -

Y

sub s trate remo v a l ra t e pro

- d e c ay ra t e ,

b

v max

u n i t s ludge ma s s ,

r

X

- h a lf v e lo c ity c o n s tant , K s The d a t a i n c lude s expe rimen t a lly d e t e rmined c o n s t a n t s , and c o n s t a n t s u s e d i n mode llin g, the lat t e r b a s e d o n mo re o r le s s e x t e n s ive li t e ra ­ ture rev i ew s . T h e expe rimen tal d a t a for the y i e ld c o e ffi c i e n t s f i t s well i n t o the theore t i c a l p i c ture e s tabli s h ed by Bauchop and Els den (1960 ) (b a s ed on the idea o f 10 .S g c e lls formed pe r mo le AT P gen e ra t e d ) and by Mc C a rty (197 1) b a s ed on fre e ene rgy re la t i o n s h i p s w i t h a s uppo s e d 60 perc e n t metabolic e n e rgy e ffi c i en c y . The metabolic e n e rgy e ffi c i e n c y mu s t n o t b e c o n fu s e d w i th the c a rbon re covery conc e p t (Roe ls 1980 ) wh i ch de s c ribe s the amount of c a rb on in the produced b a c te r i a a s com­ pared to the c a rbon i n the s ub s tra t e . Thauer et a l. (197 7 ) shows that a mo re d ivers i fi e d i n t e rp re t a t ion of ene rgy y i e ld s b a s e d on ATP pro ­ duc t i on should b e u s e d , but t h e magn i tude (10 g c e lls/mo le ATP ) s e ems to b e re a s o n ab le . Conc e rn i n g the s u b s tra t e remova l ra t e , rX' McC a rty (197 1) a s s ume s th at a n a e rob i c b a c te ri a can me taboli z e 1- 2 e le c t ro n equivalen t s p ro g c e lls pro d a y a t a t emp erature o f 3So C . When t a k i n g i n t o a c c ount t h e unknown fra c t i o n s o f a c t ive m i c ro o rga n i sms in t h e inve s t i ga t i o n s quo t e d , t h e n the max imum s ub s t rate removal rate a t 3So C fo r a b a c t e r i a l culture w i t h 10 0 % a c t ive b i oma s s c an be e s t imated to 10 - lS kg COD/ (k g V S S · d). Th i s h o ld s fo r ac i d a s w e ll a s methane p ro ­ duc ing b a c te ri a . Th i s doe s n o t me an t h a t a c omb ined c ultu re i s able to me taboli z e that mu ch. As the a n a e rob i c re a c t i o n i s s e que n t i a l, the active b i oma s s mu s t i n c lude b o th a c id p roduc ing and methane pro duc ing bac teri a . The y i eld c o e ffi c i e n t s given in t able 3.2 to 3.4 ind i c a t e s a ra t i o fo r t h e two type o f b a c te ri a t o be 0 .lS/ 0 .0 3. Ac c o rd i n gly 1 k g of a c t ive d i ge s t i n g b ioma s s c o n s e qu e n t ly c o n t a i n s 8 3 3 g o f a c i d p ro ­ duc e rs a n d 167 g o f me thane p ro du c e rs , o f wh i c h t h e la tte r a re the bott le n e c k of the re a c t i o n . T o ge th e r they c an me taboli z e appro x . 2 kg C O D / k g V S S · d a s s h own i n table 3.S. I n pra c t i c e SO% o f t h e VS S as a c t ive b i oma s s mu s t o ften be c on s i de re d a max imum. Th i s giv e s a o sub s tra te removal ra te at 3S C o f appro x im a t e ly 1 kg COD/ (k g VS S · d) as the maximum obta i n ab le . Th i s c omp a re s we ll w i th the v a lue s found with vari o u s s o luble wa s t e s (Le t t inga et a l. 1980 a , P e tte et a l. 1980 Youn g and Mc C a rty 1967 , Fro s te ll 1980 , Marten s s on and Fro s t e ll 1982 ). The d a t a given in table 3.2 - 3.4 a re rea s on ab ly h omo ge n e o u s , wh i c h allows a gen e ra li z a t ion a s shown i n table 3.S, whe re a s e t o f d a t a is p re s e n t e d wh i c h a re b e lieved to b e rep re s e n ta t iv e . The b a c teria wh i c h c a n produce methane from hydro ge n a n d c a rbon d i o x i ­ de have n o t b e e n taken i n t o c o n s i d e ra t i o n above . T h e y h a v e a h i gh e r growth ra te than t h e a c e t i c a c i d u t i li s i n g methane p roduc e rs , but i t i s n o t po s s ible t o opera t e an a n a e rob i c p ro c e s s on t h e hydro gen u t i l i ­ sing b a c t e ri a a lo n e . T h e re n e e d to b e e o rga n i sms p re s e n t , able to c o n ­ vert t h e a c e t i c a c i d p roduced and t h u s the a c e t i c a c i d methane b a c t e ­ ri a b e c ome s t h e lim i t i n g one s i n an a n a e rob i c p ro c e s s a s men t i o ne d earli e r.

-1

S

x

0 . 15

0 . 15

0 . 192

35

0 . 10

0 . 41

7.5

38

0 . 87

0 . 54

>1.33

0.2 6

37

0 . 79

37

0 . 40

3.8

Bauchop and E l sden Theoreti c a l

(1975)

Mc Carty ( 1 9 7 1a )

Syke s Theoret i c a l / mode l ( g lucose )

Theoret i c a l ( gl u c o s e )

Andrews and P e a r s on (1965) Mixed

(1960)

Speece and McCarty (1964 )

Gho s h et a l . ( 1 9 7 5 )

( 19 6 7 )

( 19 7 5 )

(1981 )

Ac id produc ing S ludge ( s ludge feed )

Young and McCa rty

2.2

2.0

Mixed anaero bic

Mue l l er and Manc in i

Mixed anaero bic

1

( 19 8 2 )

E a s tman and Ferguson

( 19 7 4 )

0 . 15

Ac id produc ing s ludge

Gho sh and Pohland

---- - -- ------------ ---------- �

-

L ite rature

L i ndgren

35

0 . 43

Mixed anaero b i c ( dextro se )

------------- ---

Cu lture/ s ubstrate

Mixed anaero b i c ( mode l )

37

------

°c

Tempe rature

6.1

------

-

d- 1

b

Decay rate

0 . 88

------- ---

kg COD/ ( k g VSS · d )

r

Sub strate remova l rate

0 . 2 5- 3 . 2

0 . 023

---

-------

kg COD/ m3

K

Half ve l o c ity c on stant

0 . 08

0 . 34

0 . 17

---------

kg VS S / kg COD

Y

Yield c oe f f i c ient

Growth con stants o f a c i d produc ing anaerob i c bacte r i a

0 . 12

30

--------

d

llmax

Max imum s pe c i f ic growth rate

Table 3 . 2 .

tx1 ::-;: o tx1 lfJ



'"

Pl ::J P.

z N tx1

Ell

::-;:

00

kg V S S / kg COD

Y

Y ie ld coe f f i c i ent

S

k g COD/ m3

K

Ha l f ve loc i ty c ons tant

x

kg COD/ ( kg VSS ' d )

r

Sub s trate removal rate

d -I

b

De c ay rate

°c

Irature

[r empe -

Mi xe d ( de s i gn )

Culture/ s u l s trate

35 35

18 . 3

30 . 9

0 . 28

0 . 13

3 .8

.7

35

7. 2

0 . 37

33

0 . 14

2. 7

-

.

I

( 1 9 78) ( 1 9 78

Gho s h and K l a s s Ghosh a n d K l a s s

S ewage s ludge Ce l lu l o s e e n r i c hm .

( 1 982 ) ( 1 9 78 )

Gu j e r and Z e hnder

i

------------------------------

L i t e r a ture

Gho sh and K l a s s

G l u c o s e e n r i c hm .

---- - -- -- - ------ --- - --- - - -----------1------- ------- ----------------

flmax d- I

�ax imum spe c i f i c growth a te

Tab le 3 . 2 c o n t inued

:v

\D

rt ro < f-'­ ro :;:

� f-'­ rt ro rt IlJ rt C rt ro

ax imum pec i f i c rowth ate

kg VSS/ kg COD

Y

Y i e ld c oe f f i­ c ient

I

4

x

0 . 002

r kg HAc / ( k g V S S·d )

S

I

d- 1

b

D e c ay Subs trate ( HAc or r a te HAc equiv . ) removal rate

kg HAcl mS

K

Half ve l o c i ty c on s tant

°c

Tempe-

I r a ture

1

C u l ture/ r ema r k s IL i t e rature

I

( 19 7 5 )

0.03

0 . 04

\

( Th e o re t i c a l / mode l ) 35

( 1 9 7 la )

Ace t a te enrichment Speec e a t a 1 . ( 1 9 8 2 ) 35

10- 12

0 . 060

McCa r ty

( Exp . bed/mode l ) 35

0.8

1. 00 7.5

( F ixed b ed/mode l ) ISw i t z e nb aum ( 1 9 8 2 ) "

( Mode l ) 35

0 . 160

25

( 19 8 2 )

Mo s e y

( 1982 )

0.4

0 . 02

L indgren Mi xed anae rob ic/ mode l

( 19 6 9 )

( 19 7 4 )

0 . 950

0 . 0 0 80 . 080

Gho s h and Pohland Anaerobic s l udge

37

0 . 600

( 19 7 5 )

( 19 81 )

3.4

H a r tmann

( 19 7 7 )

Kaspar

An aerobic s l udge Mode l

33 30

L awrence a n d McC a r ty

Ac etate en ric hment

( 1967)

35

C appenb e r g

0 . 0 1 -1 0 . 02

0 . 02

Ac e ta t e e n r i c h ment

4 . 5-7 . 5

8.2

30

0 . 20 0

0 . 019

0 . 160

"

0 . 010

0 . 0 4 50 . 055

0 . 04

"

Young and McCarty

"

(1977 )

van de n B e r g

Acetate e n r i ch­ ment

Mixed anae rob i c

20

2.4

0 . 05 0 . 04

30

2 . 4- 4 . 8

0 . 02

0 . 05

35

2 . 4-4 . 8

0 . 02

0 . 26

0 . 34

0 . 0 810 . 0 9

Mue l l e r a n d Manc i n i

Mixed anae rob ic

�-------�---------�---------.-----------.------�------�------------------�-------------------------------

d- 1

� max



Tab le 3 . 3 . Growth constants o f methane produc ing b a c te r i a

t':I en

i

'"d

§

p..

z N t':I

EiJ

:J::

...... o

S



. 49

.3

1.33

�.4 � . 5- 0 . 7

10 · 2 4

0.4

d-1

jll max

ax imum spec i f ic rowth rate

x

4.7

0 . 869

0 . 28

0 . 14

33 35

3.9

38

I

(1965) ( 19 8 2) (1978)

Gu j e r and Z ehnde r

Andrews and Pearson Ac e tate e n r i c hm . Gho sh and K l as s

Mixed ( de s ign )

M i xed

"

38

3.7

Ac e tate e n r i chm.

Ace tate e n r i c hm . IPol e t al . ( 1 9 8 2 ) 30

2 . 1- 2 . 2

0.2

( 19 80 )

( 19 7 9 ) ( 19 7 8 )

Z inde r and Mah Smith and Mah

Pure c u l ture Pure c u l ture

36

"

50

"

0.3

0 .02

I

Ande r s on and Duar te

( 1 9 7 1)

( 1 9 6 0)

Le tt inga e t a1 . ( 1 9 8 0 a ) Mixed ( s oured s ugar - b e e t was te )

( Mode l )

(1971 )

Andrews and Grae f

( Mode l /Mixed c u l tu r e)

Lawre n c e

Bauchop and E 1 sden

L i te rature

( Th e o r e t i c a l )

Cu 1 ture / rema r k s

0.3

30

( 0 . 70 . 9)

0 . 0 30 . 04

0 . 0 30 . 04

30

25

30

35

°c

Tempe­

( 0 . 60.9)

0 . 02

0 . 0 10 . 04

d- 1

b

D e c ay

I rate I rature

0 . 070 . 09

0 . 070

4.8

0 . 333

0 . 04

8.1

0 . 154

kg HAc / ( k g vss·d )

r

0 . 0 40 . 05

kg HAc / m3

S

Sub s t rate ( HAc o r HAc equiv . ) removal rate

0 . 002

I

K

Hal f ve loc ity c o n s tant

Growth con s tant s of me thane producing bac te ria

0 . 06

( 0 . 0 39)

kg VS S / kg COD

Y

Y i e ld c oe f f i­ c ient

Tab l e 3 . 3 cont inued .

:>

..... .....



'1 ro 75

90

Bean b l anch ing un soured

30 Da i ry

97

Sauerkra ut

30

P a lm o i l

Long - c h a i n s a t . f a tty a c ids .

1 . 1- 1 . 4

100

-

Gluc o s e , peptone 1 0 0

Glucose

Synthe t i c

30

4.0

3.0

0.2

38

Hexo s e ( Theor e t ic a l )

37

0.5

%

Solubil i ty index

- - - - - - - - - - - - - - - - - -- - - - - - - - - - - -- - -- - - 100 Hexo s e

Type of wa s te

0 . 1- 0 . 4

75

S ug a r - b e e t , s oured

B e a n b l an c h ing

S au e r k r a u t

1.1 35

S ludge b l ank e t

99

H e a t tr e a t l i qu o r / B r ewery

--

620 ' 10

35

F ix e d b e d , down f low

99

Heat treat l i qu o r / B r ev e r y

-3

-3

-3

-3

-3

-3

-3

-3

-3

0.9

35

F ix e d b e d , Up- f l ow

99

Heat treat l iquo r / B r ewery

29 ' 10

35

F lu i d i z e d bed

99

Heat treat l i quot/Brewery

4 0 ' 10

37

Recyc l ed bed

-90

Sugar beet

4 0 ' 10

Recyc l ed b ed

100

Mo l a s s e s , d i luted

37

Whey

D a iry Expanded b ed

61 ' 10

30

S ludge b l an k e t

A l coho l i c

95

-3 3 . 10

m

Reactor vo lume

S u g a r-b e e t , u n s oured

°c

T emp er a tu r e

30

Type o f reactor

0 . 3-0 . 5

0 . 4-0 . 6

0 . 8-1 . 2

( 19 8 2 ) (1982)

Hall Ha l l

12 . 9 7.3 13 . 5

( 19 8 2 ) Ha l l 14 . 5 42 . 3 35. 1

(1982) Hall 4.6

M a r t en s s o n and Frostell ( 19 8 2 )

M a r t en s s on and F ro s t e l l ( 1 9 8 2 )

Swi t z enbaum and Danskin ( 1 9 8 2 )

L e t t ing a e t a l . ( 19 80a)

L e t t ing a e t a l . ( 1980a)

L e t t i ng a e t a l . ( 19 80a)

Lettinga et a l . ( 1 9 8 0a )

0 . 8-1 . 0 0 . 6-0 . 8

Lettinga et a l . ( 19 8 0a )

L e t t ing a e t a l . ( 19 7 9 )

L i terature

0 . 5-0 . 8

0.5

9 . 3-18 . 8 0 . 6-1 . 3

8 . 6-8 . 7

40

-15

-9

_ 13

-

_7

36

kg V S S 3 m

S ludg e ma s s load k 0 . 6 k g cool ( kg V S S · d ) i n order to f roduc e � ranu 1 e s . H igh Ca + in was tewa ter i n c r ea s e s b i omas s wash - out and s tart - up p er iod

* Wi thout s eed ing : no gas produc t ion and b i oma s s accumu l a t ion f o r 1 month

* 4 t ime s f a s te r s ta r t up w i th s ludge f r om i d e nt ic a l p r o c e s s than w i th mun i c ip a l d i g e s ter s l udg e

* S ta r t - up per iod de pends upon type o f i n e r t med ia

* Load ing i n c r e a s ed 2 5 - 1 0 0 % per week

Ob s erva t i o n s / Re c ornmen d a t i o n s du r ing up - s t a rt

T a b l e 7 . 5 c o n t i nued

I

I

0 . 0 5-0 . 1 COOl ( kg VSS · d)

1 kg cool ( m3 · d l

Initial l o a d in g

2-3

1.5

S ludg e b l anket

F ixed bed

F ix e d bed

F ix e d bed

8-13 0 . 3-1 . 3

F ix e d bed

F ix e d bed

F ix e d bed

Type o f reactor

1-3

2

months

S t a r t - up period

( 19 7 5 )

Pol e t a1 .

( 1982)

Chian and O eWa 1 1 e ( 1977)

Young and McCarty ( 19 6 7 )

van den Berg and Lentz ( 19 7 9 )

van d e n Berg and K ennedy ( 1 9 8 1 )

B e n j am i n e t a 1 . ( 1981)

Arora e t a 1 .

L i te r a ture

tYj CJl

I

'"0

III ::l p.

� Z N tYj

:;::

" "'"

p iges ter

Method

..

...

s ludge

*Ad d i t ion o f s l ime pro duc ing o r g a n i sms

*Ae rob i c o pe r a t ion ahead of s ta r t - u p

*Carbohydrate f o r s l ime produc t ion

*Porous s ur f a c e o f c a r r i e r mate r i a l

*T empe r a tu r e � 35 0 C

*Ac e t i c a c id