Anaerobic filtration of waste waters arising from the production of bakers' yeast : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Biotechnology at Massey University

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ANAE ROB I C F I LTRAT I ON O F WASTE WATERS ARIS I NG FROM THE PRODUC T I ON OF

BAKERS' YEAST

A t h e sis p r e s e n t e d i n p a r t i a l ful f i l m e n t o f t h e r e q u i remen t s for t h e d e g r e e o f D o c t o r o f Ph i l o s o phy i n B i o t e c hn o l o g y a t Ma s s e y U n i v e r s i t y .

JOHN W I L L I AM BARNETT 1 9 8 4

AB STRACT

A s t udy w a s c a r ried out to a s s e s s t h e e f f e c tiven e s s o f t h e a n a e r o bic fil t r a tion p r o c e s s in p r o vidin g a r e l a tive l y si�p l e o n - si t e was t e p r e t r e a t m e n t s y s t em fo r t h e w a s t e s from t h e p roduc tion o f b a k e r s ' y e a s t . T h e s e a r e of a high s t r e n g t h and acidic n a t u r e . To main t ain p r a c tic a l c o n ­ s t r ain t s o n t h e p r o j e c t a r e a l w a s t e w a t e r w a s u s e d . The wa s t e w a t e r is l ow in s u sp e n d e d m a t e ria l , h a s a hig h o r g anic ma t t e r c o n c e n t r a tion giving a COD o f 7 0 0 0 0 t o 9 0 0 0 0 mg/1 ( BOD 5 1 4 2 5 0 m g / 1 ) and a p H o f 4 . 5 t o 5 . 0 . Two e x p e rime n t a l anae robic fi l t e r unit s w e r e c o n s t r u c t e d o f g l a s s c y linde r s p a c k e d wit h g l a s s 'Ras chig ' rin g s a s t h e in e r t s upport mat rix , a n d u s e d i n t h e t ria l s . A s t a tis tic ­ a l l y d e s i g ned expe rime n t a l p r o g r amme w a s u s e d t o t e s t t h e e f fe c t s o f in f l en t s ub s t r a t e c o n c e n t r a tion , hyd r a u lic r e t e n tion time , t emp e r a t u r e and fi l t e r u n i t o n t h e fi l t e r r e s po n s e v a riab l e s . Subs t r a t e c on c e n t r a t io n s o f 5 5 0 0 t o 4 7 2 0 0 m g �OD / 1 ( 1 0 0 0 t o 9 0 0 0m g BOD 5 / 1 ) a n d h y d r a u lic r e t e n tion tim e s of 1 to 5 days w e r e u s ed whi c h g ave ris e t o o rg anic l o ading r a t e s o f 1 . 1 5 t o 4 7 . 2 k g C OD / m 3 d

( 0 . 2 t o 9 . 0 k g BOD 5 ; m3 d ) . Emriric a l mode l s w e r e d e rive d

f r om t h e r e s p on s e da t a , u sing mu l tip l e r e g r e s sion t e ch nique s , and d e s c rib e COD remova l r a t e , t o t a l g a s p ro du c tion , me t hane p roduc t i on and c o n v e r sion of COD to m e t h a n e in t e rm s of t h e ind e p e nd e n t p r o c e s s v a riab l e s . R e s u l t s s h owed t h a t t h e

a n a e r o bic fil t e r a c hieved COD r emova l s o f 3 4 t o 6 5 p e r c e n t wit h c o r r e s po nding c o nve rsions o f 2 4 t o 7 8 p e r c e n t e f fici e n c y

t o m e t hane a t l o adin g s o f up t o 4 7 . 2 k g C O D / m 3 d . The

empiric a l e q u a tion s were ab l e to e x p l ain 9 2 to 9 7 p e r c e n t o f t h e ob s e rv e d v a rian c e . T h e s y s t em w a s s t ab l e o v e r t h e e n ti r e r a n g e o f app lied c onditio n s .

AC KNOW L E G EMENTS

I wou l d l i k e to e x t e n d my g r a t i t ud e to the fo l l ow i ng

My s u p e r v i s o r s , P r o fe s s o r R . L . E a r l e and O r V . F . L a r s e n fo r t h e i r g u i d a n c e and a b o v e a l l t he i r p a t i en c e o v e r t h e y e a r s .

The B i o t e chno l o gy D e p a r t m e n t fo r t h e u s e o f t h e i r fa c i l i t i e s , and e s p e c i a l l y J o h n A l g e r f o r i nv a l uab l e a s s i s t an c e w i t h c o n s t r uc t i o n and m a i n t e n anc e o f t h e e q u i pm e n t .

D r Mary E a r l e fo r h e r c o n t i n ued e n c o u r a gement and a s s i s t an c e w i t h the p r e p a r a t i o n of t h e manu s c r i p t . J o anne fo r g i ving up he r t ime t o do t h e t y p i n g . The D S I R fo r p r ov i d i n g t h e g r a n t wh i ch e n ab l ed t h e p r o j e c t t o p r o c e e d .

1 2

3

TAB L E O F CONTENTS

TAB L E S P REAMB L E

L I T E RATU RE SURVEY

2 . 1 P r o du c t i on of b ak e r s ' y e a s t

2 . 1 . 1 B i o c h em i s t ry o f y e a s t p ro p ag a t i o n 2 . 1 . 2 P ro c e s s d e s c r i p t i o n

2 . 1 . 3 S ou r c e s o f e ff l u e n t from b ak e r s' y e a s t p r o p a g a t i o n and t h e i r c h a r a c t e r i s t i c s 2 . 2

2 . 2 . 1 2 . 2 . 2 2 . 2 . 3 2 . 2 . 4

2 . 3 2 . 3 . 1 2 . 3 . 2 2 . 4 2 . 4 . 1 2 . 4 . 2 2 . 4 . 3 2 . 4 . 4 2 . 4 . 5 2 . 4 . 6

T r e a t me n t o f w a s t e w a t e r s a r r i s i n g f r om t h e p r o d uc t i o n o f c omme r c i a l b a k e r s ' y e a s t

C h em i c a l t r e a t m e n t o f ye a s t p l an t e f f l ue n t A e r ob i c b i o l o g i c a l t r e a tm e n t o f y e a s t

p l a n t e f f l u e n t

An a e rob i c b i o l o g i c a l t r e a tm e n t o f y e a s t p l an t e f f l u e n t

M i x e d a n a e r o b i c a n d a e rob i c b i o l o g i c a l t r e a tm e n t o f y e a s t p l an t eff l ue n t

T h e a n a e rob i c w a s t e t r e a t m e n t p r o c e s s

Th e o re t i c a l a s p e c t s o f me t h an e p r o du c t i o n A n a e r o b i c p r o c e s s d e s i gn s

The a n a e r ob i c f i l t e r F i l t e r d e s i gn

Op e r a t i on a l c o nd i t i on s

Remov a l o f o r ga n i c ma t e r i a l C o n ve r s i o n o f COD t o me t h a n e

Re c i r c u l a t i on o f t h e f i l t e r e f f l u e n t F i l t e r s t a r t - up

2 . 4 . 7 N u t r i e n t r e q u i remen t s

I NT RODUCT I ON TO T H E E X P E R I MENTAL D E S I GN 3 . 1 S t atist ical e xp e r i m e n t a l de s i gn s 3 . 2 S y s t em mod e l l i n g

3 . 3 Typ e s o f e x p e r i me n t a l d e s i g n 3 . 4 D a t a ana l y s i s

1 3 3 3 7 9 1 2

1 3 1 4 1 9 2 3

2 6 2 6 3 5 3 8 3 9 40 4 5 5 8 6 0 6 1 6 2 6 3 6 3 6 5 6 7 7 0

4

5

E X P E R I MENTAL PROGRAMME 4 . 1

4 . 2 4 . 2 . 1 4 . 2 . 2 4 . 2 . 3 4 . 3 4 . 4 4 . 5 4 . 5 . 1 4 . 5 . 2 4 . 5 . 3 4 . 5 . 4 4 . 5 . 5 4 . 5 . 6 4 . 5 . 7

S c o p e o f t h e s tudy Expe r i men t a l p r o c e d u r e

Se l e c t i on o f t h e v a r i ab l e s t o b e t e s t e d Se l e c t i on o f t h e e x p e r i m e n t a l d e s i gn S e l e c t i o n o f t h e fac t o r l eve l s

Equ i pment

S amp l i ng p r o c e du r e s Ana l y t i c a l t e chn i qu e s

C h em i c a l o x y g e n demand

5 day b i o c h em i c a l o x y g e n d emand p H

S u s pe nded s o l i d s Ammo n i a

S u l ph i de A l k a l i n i t y 4 . 5 . 8 G a s p r oduc t i on

4 . 5 . 9 Me t h a n e c om p o s i t i o n o f g a s 4 . 5 . 1 0 Vo l a t i l e a c i ds

E X P E R I MENTAL R E S U LTS

75 75 7 6 7 6 7 7 7 8 8 1 8 3 8 4 8 4 85 85 85 8 6 8 6 8 6 8 6 8 7 8 7 8 9 5 . 1 S t e ady s t a t e e xp e r i m e n t a l d a t a 8 9 5 . 2 The e ffe c t o f t h e exp e r i me n t a l f a c t o r s o n t h e 9 5

r emov a l o f C OD a n d BOD5

5 . 2 . 1 Remova l o f s o l ub l e COD 95

5 . 2 . 2 5 . 2 . 3

5 . 3

5 . 3 . 1 5 . 3 . 2 5 . 3 . 3 5 . 4

Temp e r a t u r e e f fe c t s o n s ub s t r a t e r emov a l Remova l o f BOD5

The e ffe c t s o f t h e exp e r i m en t a l f a c t o r s o n g a s and m e t h an e p roduc t i o n

G a s p roduc t i on Me t hane p r o du c t i o n

Me t hane c o n t e n t o f t h e d i g e s t e r g a s

The e f fe c t s o f t h e e xp e r i me nt a l f a c t o r s o n o t h e r r e s po n s e v a r i ab l e s

5 . 4 . 1 E f f l ue n t p H

5 . 4 . 2 V o l at i l e a c i d conc e n t r a t i on

1 0 6 1 0 8 1 1 3

1 1 3 1 1 6 1 18 1 25 1 25 1 25

6

7

8 9

5 . 4 . 3 Ammo n i a l e ve l s 1 2 9

5 . 4 . 4 S u l ph i de con c e n t r a t i on s i n t h e f i l t e r 1 3 1 e f f l ue n t

5 . 4 . 5 A l k a l i n i ty 1 3 1

5 . 5 T h e e f fe c t o f f i l t e r c o l umn h e i gh t 1 3 3

P E RFORMANC E O F TH E ANA E ROB I C F ILTE RS 1 3 8

6 . 1 I n t r o du c t i o n 1 3 8

6 . 2 The t r e a t m e n t o f h i gh s t r e n g t h w a s t e w a t e r 1 3 9 b y a n a e ro b i c f i l t r a t i o n

6 . 2 . 1 Remo v a l o f o r g a n i c m a t e r i a l b y t h e a n e r - 1 4 1 o h i c f i l t e r s

6 . 2 . 2 C on v e r s i on o f o r g an i c m a t e r1a l t o m e t h an e 1 4 9 6 . 3 E n v i r o nme n t a l fac t o r s w i t h i n t h e f i l t e r s 152 6 . 3 . 1 Vo l a t i l e a c i d c o n t e n t 1 5 2

6 . 3 . 2 Ammo n i a c o n c e n t r a t ion 1 Sj

6 . 3 . 3 The e f fe c t s o f s u l p h a t e i n t h e f e e d 1 5 4 6 . 4 T h e a n a e r o b i c f i l t e r a s a p r e t r e a tme n t f o r 1 5 7

y e a s t p l an t e f f l u e n t

MOD E L L I N G O F T H E ANAEROB I C F I LT RAT I ON O F YEAST WAS T E

7 . 1 I n t r o d uc t i o n

7 . 2 The s y s t em r e s po n s e e q ua t i o n s 7 . 2 . 1 C O D r emova l r a t e

7 . 2 . 2 T o t a l g a s p roduc t i o n 7 . 2 . 3 M e t h an e p r oduc t i o n 7 . 2 . 4

7 . 3

7 . 3 . 1 7 . 4

C o n v e r s i o n o f COD t o m e t h a n e I n t e rp r e t a t i o n a n d o p tim i s a t i on o f t h e mode l s

Max i m a l o p e r a t i n g c o nd i t i on s

S t a s t i c a l l ac k o f f i t o f t h e mode l s 7 . 5 T r en d s i n t h e d a t a

7 . 6 Th e u s e o f t h e w a s t e t r e a tm e n t mode l s ON - S I T E PRETREATMENT O F YEAST P LANT E F F LUENT C ON C L U S I ON S

R E F E RENC E S APPEND I C E S

159

159 1 6 1 1 6 1 1 6 2 1 6 3 1 6 4 1 6 9

1 7 9 1 8 1 1 85 1 9 0 1 9 7

2. 1 2. 2 2 . 3 2. 4 2. 5

2 . 5 a

2 . 6

2 . 7 2 . 8

2 . 9 3 . 1

4 .1 4 . 2 4 . 3 4 . 4

5 . 1 5 .2 5 . 3 5 . 4 5 . 5

5 . 6

L I ST O F TAB L E S

E l eme n t a l c omp o s i t i on o f y e a s t s a n d mo l a s s e s Po l l ut i o na l l o a d o f l i q u i d wa s t e s t r e am s C omp o s i t i o n o f s p e n t l i q u o r from b a k e r s ' ye a s t p r o p a g a t i o n

Ac t i va t e d s l ud g e t re a t m e n t o f y e a s t p l an t e f f l ue n t

Remova l o f o r g an i c ma t e r i a l b y anae r o b i c d i g e s t i o n

G a s p roduc t i o n from t h e anae rob i c d i g e s t i o n o f y e a s t p l a n t e f f l ue n t

S t e ady s t a t e p e r fo rm a n c e d a t a fo r s ome a n a e rob i c f i l t e r s

De t a i l s o f r e g r e s s i o n lin e s i n F i gu re 2 . 7

F i r s t o rd e r kine t i c c o n s t an t s fo r remo v a l o f COD by an a e rob i c f i l t e r s

Me t h ane y i e l d s fo r a n a e rob i c f i l t r a t i o n E xpe r i m e n t a l d e s i g n for a fu l l fa c t o r i a l e xpe r i me n t i nvo l v i n g t h r e e fac t o r s a t two l e ve l s e a c h

Expe r i me n t a l d e s i gn

Expe r imen t a l s c o p e o f t h i s s t udy

Gas c h roma t o g r ap h c o nd i t i o n s fo r de t e r ­ m i na t i o n o f me t hane i n d i g e s t e r g a s G a s l i q u i d c h r oma t o g r a p h c o nd i t i o n s fo r vo l a t i l e ac i d a n a l y s i s

S t e ady s t a t e d a t a from t h e e xp e r ime n t a l d e s i gn C o r r e l a t i o n c o e f f i c i e n t s fo r d a t a i n T a b l e ^{5 . 1} S t e ady s t a t e d a t a from runs n o t i nc l ud e d i n

t he e xp e r i me n t a l de s i g n

I nd i v i du a l vo l a t i l e a c i d c o n c en t r a t i o n s m e a s 7 ured at s t eady s t a t e :ond i t i o n s

D a t a from t h e r e p e a t e xp e r i me n t a l r u n s t o a s s e s s t h e e f fe c t o f s u l ph i de o n f i l t e r p er ­ fo rmanc e

S t e ady s t a t e COD, p H , a n d ammo n i a l eve l s a s a func t i o n o f c o l umn h e i gh t

6 9 1 1 1 7 2 1

2 2

4 1 4 7

5 3 59

64 7 8 8 0 8 7

8 8 9 1 93 9 4 1 2 8

1 32 13 7

7 ⁰ 1

7 ⁰ 2 7 . 3 7 ⁰ 4 7 ⁰ 5 7 . 6

7 . 7 7 . 8 7 . 9

7 o1 0

7 ⁰ 1 1 8 o 1

8 ⁰ 2 8 . 3

Re s p o n s e d a t a and c o d e d e xp e r i me n t a l d e s i gn fac t o r s u s e d i n t h e r e g r e s s i o n a n a l y s i s R e g r e s s i o n p a rame t e r s fo r COD remo va l mod e l Re g r e s s i o n p a r ame t e r s fo r g a s p r oduc t i o n mode l

Re g r e s s i o n p a rame t e r s for me t hane p r o d uc t i o n mode l

Re g r e s s i o n p a r ame t e r s for c o nve r s i on o f C O D t o me t h a n e mo de l

Ob s e rved, p r e d i c t e d and re - eva l ua t e d va l u e s fo r t h e re g r e s s i o n mode l p a rame t e r s

Rep l i c a t e d a t a f o r l ac k o f f i t t e s t Oneway a na l y s i s o f var i an c e s umma ry fo r rep l i c a t e run s

Lack o f fit ana l ysis for COD remo v a l and me t h ane p r o d uc t i o n mo d e l s

Ob s e rved and p re d i c t e d va l ue s o f Y i n t h e r e s p o n s e equa t i on s and t h e r e s i dua l s

Re g r e s s i o n ana l y s i s o f p l o t s i n F i gu r e 7 0 1 4

F a c t o ry d i s c h a r g e s o f s p e n t med i a and y e a s t c re am w a s h w a t e r s

1 60 1 6 5 1 66 1 6 7 168

1 8 0 1 8 2 1 8 3 1 8 4

1 8 6 1 9 3

1 9 7

On-s i t e t r e a t m e n t p l an t o p t i o n s ^{1 9 9} Comp a r i s o n o f s e ve r a l t r e a t m e n t p l an t o p t i on s 20 0