(maybe 5 0 % of the yield at 3 50C) , wh ich results in very s low s tart up and very s low accomodation ...... Braun ( 19 8 1 ). Norman ( 1 9 8 1 ). Bories ( 1 9 8 1 ) ...
Wat.Sci.Tech.
Vol. 15,
Copenhagen,
Printed in Great Britain.
pp.I-IOI.
Copyright © 1983
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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