and 20 days MCRT polishing reactors were eliminated. The leachate employed was lysimeter generated and characterized by COD and BOD,. concentrations of ...
EFFECTS OF TEMPERATURE ON TWO-STAGE BIOSTABILIZATION OF LANDFILL LEACHATE
by
Reidar
Zapf-Gilje
B.Eng., M c G i l l U n i v e r s i t y , M o n t r e a l , 1977
A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF APPLIED
SCIENCE
in
THE FACULTY OF GRADUATE (The Department o f C i v i l
STUDIES
Engineering)
We a c c e p t t h i s t h e s i s as conforming t o the r e q u i r e d
THE UNIVERSITY
OF BRITISH COLUMBIA
October (cT)
standard
1979
R e i d a r Zapf-Gilje., 1979
In presenting this thesis in partial
fulfilment of the requirements for
an advanced degree at the University of B r i t i s h Columbia, I agree that the Library shall make it freely available for reference and study. I further agree that permission for extensive copying of this thesis for scholarly purposes may be granted by the Head of my Department or by his representatives.
It
is understood that copying or publication
of this thesis for financial gain shall not be allowed without my written permission.
Department of
Tj-
B-hJc^/Nfcg/^vM^
The University of B r i t i s h Columbia
2075 Wesbrook Place Vancouver, Canada V6T 1W5
Date
C%&r(fi«r
h=M
(ii)
ABSTRACT
Leachate i s generated by seepage o f water through s a n i t a r y l a n d fills. and
Where c o n d i t i o n s a r e u n f a v o u r a b l e ,
leachate
o f high
strength
l a r g e volumes may be produced, thus c r e a t i n g t h e p o t e n t i a l f o r s e r i o u s
water c o n t a m i n a t i o n problems. T h i s study i n v e s t i g a t e d a e r o b i c , two-stage b i o l o g i c a l t r e a t m e n t o f h i g h s t r e n g t h l e a c h a t e , a t d i f f e r e n t o p e r a t i n g temperatures. mixed b a t c h
r e a c t o r s o f 10 l i t r e volume were employed and operated
daily fill-and-draw basis. B0Dj-:N:P = 100:5:1. at
and
N u t r i e n t l o a d i n g was s l i g h t l y i n excess o f
A t room temperature t h e f i r s t
a t a mean c e l l r e s i d e n c e
time
stage r e a c t o r s t h a t were operated
stage r e a c t o r s
(MCRT) o f 6, 9 and 20 days
the p o l i s h i n g r e a c t o r s a t 6, 9, 10 and 20 days.
the f i r s t
on a
Two-stage b i o l o g i c a l treatment were performed
23-25°C, 16°C and 9°C.
were operated and
Completely
A t lower temperatures,
a t 20 days MCRT and the 10
20 days MCRT p o l i s h i n g r e a c t o r s were e l i m i n a t e d .
The l e a c h a t e
employed was l y s i m e t e r generated and c h a r a c t e r i z e d by COD and BOD,. concentrations
o f a p p r o x i m a t e l y 19,000 mg/L and 14,000 mg/L r e s p e c t i v e l y .
In a d d i t i o n , i t c o n t a i n e d
a spectrum o f heavy metals and i n o r g a n i c
solids. Organic removal by t h e f i r s t stage systems was e x c e p t i o n a l l y good.
B e t t e r than 95% COD and 99% BOD,, were removed under a l l c o n d i t i o n s
investigated.
Removal o f heavy metals was 90% o r b e t t e r f o r most o f t h e
9 metals m o n i t o r e d . 50%
reduction.
N i c k e l and magnesium e x p e r i e n c e d
F o r temperatures r a n g i n g
from 9°C t o 25°C the
performance was n o t s i g n i f i c a n t l y a f f e c t e d . and BODj. were s l i g h t l y h i g h e r the h i g h e s t o r g a n i c
a t 9°C,
o n l y an average o f removal
However, t h e e f f l u e n t COD
e s p e c i a l l y for the reactor r e c e i v i n g
l o a d o f 3.2 kg COD/m
3
-day.
(iii)
As a r e s u l t o f t h e low r e s i d u a l c o n c e n t r a t i o n o f o r g a n i c m a t e r i a l i n t h e f i r s t s t a g e e f f l u e n t , the p o l i s h i n g r e a c t o r s e x p e r i e n c e d washout a t all
temperatures b u t 9°C.
A t t h i s temperature and f o r t h e range o f
MCRT's t e s t e d , t h e second stage d i g e s t e r s s t a b i l i z e d a t low MLSS l e v e l s of
220-600 mg/L, removing about 45% o f t h e r e s i d u a l COD and 80% o f t h e
r e s i d u a l BOD,.; i n a d d i t i o n , manganese, i r o n and z i n c were f u r t h e r reduced by 60-80%. S e t t l i n g problems
caused by b u l k i n g , d e f l o c c u l a t i o n and p r o b a b l y
some h i n d e r e d s e t t l i n g were encountered throughout t h e experiment, e s p e c i a l l y a t lower MCRT's and temperatures.
Hence, i n o r d e r t o produce
enough f e e d f o r t h e p o l i s h i n g r e a c t o r , a l l e f f l u e n t s were o b t a i n e d by f i l t e r i n g , r a t h e r than s e t t l i n g .
The f i l t e r e d e f f l u e n t s a t i s f i e d the
l o c a l p o l l u t i o n c o n t r o l o b j e c t i v e s f o r most parameters under n e a r l y a l l c o n d i t i o n s t e s t e d ; however, s l i g h t l y h i g h e r c o n c e n t r a t i o n s a r e e x p e c t e d under f i e l d c o n d i t i o n s due t o s o l i d s l o s t i n t h e e f f l u e n t .
(iv)
TABLE OF CONTENTS
Page ABSTRACT
i i
LIST OF TABLES
vi
LIST OF FIGURES
viii
ACKNOWLEDGEMENTS
i
x
CHAPTER 1
INTRODUCTION ."
1
2
BACKGROUND
3
2.1
Sanitary
2.2
A e r o b i c B i o l o g i c a l Treatment o f Leachate 2.2.1 2.2.2 ' 2.2.3 2.2.4
3
Organic matter Heavy metal removal Temperature e f f e c t s C h a r a c t e r i s t i c s of fill-and-draw systems
EXPERIMENTAL MATERIAL AND
METHODS
3 . . .
6 7 9 12 14 18
3.1
L a b o r a t o r y System
18
3.2
E x p e r i m e n t a l Apparatus
18
3.3
E x p e r i m e n t a l Procedure
20
3.3.1 3.3.2 3.3.3 3.3.4
20 21 24
3.4
3.5
D i s s o l v e d oxygen and pH S o l i d s , COD arid B0D Heavy metals Others 5
DISCUSSION
Mixed L i q u o r
24 25
Leachate C h a r a c t e r i s t i c s
RESULTS AND 4.1
Acclimatizing Room temperature study Reduced temperature study E f f e c t s o f the f i l l - a n d - d r a w procedure
A n a l y t i c a l Procedures 3.4.1 3.4.2 3.4.3 3.4.4
4
L a n d f i l l Leachates
Characteristics
25 25 26 26 26 29 29
(v)
TABLE OF CONTENTS
(Continued)
CHAPTER
Page
4.2
Organic M a t t e r Removal
31
4.2.1
BOD
33
4.2.2
COD
33
4.3
Heavy Metal Removal
36
4.4
Temperature E f f e c t s
38
4.5
Biological Polishing
4.6
Effluent Quality
4.7
E f f e c t s o f t h e F i l l - a n d - D r a w Procedure
5
Reactors
and t h e PCB G u i d e l i n e s
40 . . . .
41 44
CONCLUSIONS AND RECOMMENDATIONS
50
5.1
Conclusions
50
5.2
Recommendations
52
REFERENCES
APPENDICES
53
. . .
55
Appendix A:
KINETICS
56
Appendix B:
SUPPLEMENTARY RESULTS
62
Appendix C:
ALKALINITY REMOVAL . . . . . . . . . . . . . . .
64
(vi) LIST OF TABLES
T a b l e No.
Title
Page
1
Composition o f T y p i c a l Leachates
4
2
Proposed R e l a t i o n s h i p Between COD/TOC, BOD/COD, A b s o l u t e COD, and Age o f F i l l t o Expected E f f i c i e n c i e s o f O r g a n i c Removal from Leachate . . . .
5
O p e r a t i o n a l Parameters f o r A c t i v a t e d Treatment o f Domestic Sewage . . .
7
3
4
Sludge
C h a r a c t e r i s t i c s o f Mixed-Liquor P r i o r t o F i r s t Leachate A d d i t i o n
20
5
L y s i m e t e r System C h a r a c t e r i s t i c s
27
6
Lysimeter Operational C h a r a c t e r i s t i c s
27
7
Composition o f Refuse
27
8
Leachate C h a r a c t e r i s t i c s
28
9
Mixed-Liquor S o l i d s C o n c e n t r a t i o n s
29
10
A p p l i e d Organic and F/M Loadings
31
11
Reported Organic Loadings and Removal E f f i c i e n c i e s f o r A e r o b i c B i o l o g i c a l Treatment o f Leachate
32
12
Organic Matter Removal i n Terms o f BOD,, and COD
34
13
M i x e d - L i q u o r COD (MLCOD) C o n c e n t r a t i o n s and MLVSS/MLCOD R a t i o s
14
. . .
36
Reported M e t a l Removal by A e r o b i c B i o l o g i c a l D i g e s t e r s T r e a t i n g Leachate
37
15
M e t a l Removal E f f i c i e n c i e s
38
16
Performance o f B i o l o g i c a l P o l i s h i n g R e a c t o r s a t 9°C C h a r a c t e r i s t i c s o f E f f l u e n t Produced by F i r s t A e r o b i c B i o s t a b i l i z a t i o n o f Leachate
17
18
42 Stage 43
Effluent Characteristics of Biological P o l i s h i n g Treatment
44
19
Data f o r D e t e r m i n a t i o n o f K i n e t i c Parameters
59
20
K i n e t i c Parameters Based on S o l u b l e BOD^ C o n c e n t r a t i o n s a t Room Temperature
59
(vii) LIST OF TABLES
(Continued)
21
F i r s t Stage E f f l u e n t C o n c e n t r a t i o n s
62
22
Mixed-Liquor BOD,., mg/L,
62
23
Mixed-Liquor COD,
24
Average Metal Removals by F i r s t - s t a g e
Versus D i l u t i o n
TC and TOC i n mg/L
63 Reactors . . . .
64
(viii) LIST OF FIGURES
F i g u r e No.
Title
Page
1
L a b o r a t o r y Reactor Design
2
MLVSS and MLVSS/MLSS d u r i n g the Acclimatizing
. . . .
19
Period
. . . .
3
MLVSS Versus MCRT a t Room Temperature
4
Removal o f COD by Reactor A, B, and C a t Room Temperature
35
Removal o f COD f o r Reactor A, B, and C a t Temperatures Ranging from 9-25 C
39
5
. . . . . .
22
6
Range o f S e t t l i n g Performance
7
Mixed-Liquor V o l a t i l e Suspended S o l i d s , D i s s o l v e d Oxygen and pH Between Leachate A d d i t i o n s o f Reactor B a t 9°C
47
S o l u b l e E f f l u e n t COD and B0D Feedings o f Reactor B a t 9°C
48
8
9
10
D e t e r m i n a t i o n o f k and K BOD,. C o n c e n t r a t i o n s
o f Reactor A
5
46
Between
Based on S o l u b l e
D e t e r m i n a t i o n o f Y and k . Based on S o l u b l e a B0D C o n c e n t r a t i o n r
. . .
30
60
rn
ol
(ix)
ACKNOWLEDGEMENTS
The Mavinic
f o r h i s guidance and u n d e r s t a n d i n g d u r i n g t h i s
He and Mrs. the
author wishes t o express h i s g r a t i t u d e t o Dr. D.S. study.
a l s o wishes t o thank Dr. R.D. Cameron, Dr. W.K. Oldham,
E.C. McDonald f o r t h e i r k i n d a s s i s t a n c e on v a r i o u s a s p e c t s o f
research.
T h i s r e s e a r c h was supported w i t h Research C o u n c i l o f Canada.
funds p r o v i d e d by t h e N a t i o n a l
-1-
CHAPTER 1 INTRODUCTION
Any method used f o r d i s p o s a l o f our waste p r o d u c t s s h o u l d minimize c h e m i c a l and b i o l o g i c a l h a z a r d s and be e n v i r o n m e n t a l l y s a f e . landfills
are s t i l l
Sanitary
c o n s i d e r e d one o f the s a f e s t and l e a s t e x p e n s i v e
methods o f s o l i d waste d i s p o s a l .
However, poor s i t e s e l e c t i o n
and
improper d e s i g n and o p e r a t i o n , c o u p l e d w i t h h i g h p r e c i p i t a t i o n , have c r e a t e d s e r i o u s groundwater
p o l l u t i o n by l a n d f i l l l e a c h a t e .
Leachate i s generated by seepage o f water t h r o u g h the f i l l .
The
water
d i s s o l v e s o r i g i n a l components and decomposition p r o d u c t s ; thus r e s u l t i n g i n a f i n a l p r o d u c t h a v i n g h i g h o r g a n i c matter and i n o r g a n i c i o n • c o n c e n t r a t i o n s . S e v e r a l i n c i d e n c e s have been r e p o r t e d where l e a c h a t e has the
s u r r o u n d i n g s o i l and p o l l u t e d nearby ground and
contaminated
s u r f a c e waters.
A
garbage dump i n K r e f e l d , Germany, contaminated w e l l s a s f a r a s 8 k i l o m e t e r s away f o r more than 18 y e a r s . 1
In a more r e c e n t c a s e , p r i v a t e w e l l s
300 meters downstream from L l a n g o l l o n l a n d f i l l Delaware,
i n New
Castle
located
County,
U.S.A., were h e a v i l y p o l l u t e d and s u b s e q u e n t l y abandoned . 2
To reduce t h e l e a c h a t e p o l l u t i o n hazard, t h r e e approaches
are
p r a c t i s e d today; p r e v e n t i o n o f l e a c h a t e p r o d u c t i o n , r e c i r c u l a t i o n o f l e a c h a t e t o the l a n d f i l l , and c o l l e c t i o n and t r e a t m e n t o f l e a c h a t e . 3
Leachate p r o d u c t i o n may
be m i n i m i z e d by i n s t a l l i n g a low p e r m e a b i l i t y
c o v e r t o p r e v e n t the p e n e t r a t i o n o f r a i n f a l l , s u r f a c e r u n o f f , and by l o c a t i n g the f i l l
by d i v e r t i n g
upstream
above the ground water
One d i s a d v a n t a g e o f t h i s approach i s the reduced r a t e o f s o l i d
table. waste
s t a b i l i z a t i o n caused by t h e absence o f water. The
second a l t e r n a t i v e i n v o l v e s s u r f a c e i r r i g a t i o n o f l e a c h a t e
on t o p o f l a n d f i l l s .
T h i s presumably
m a i n t a i n s the m o i s t u r e c o n t e n t o f
-2-
t h e s o l i d waste a t an optimum l e v e l f o r a n a e r o b i c b i o l o g i c a l d e g r a d a t i o n . The r e f u s e then f u n c t i o n s a s an a n a e r o b i c f i l t e r
s t a b i l i z i n g the
leachate. The most e f f i c i e n t method i n v o l v e s the c o l l e c t i o n o f generated l e a c h a t e f o r subsequent
b i o l o g i c a l and/or p h y s i c a l - c h e m i c a l t r e a t m e n t .
The
q u a n t i t y o f l e a c h a t e produced depends m a i n l y on p r e c i p i t a t i o n and c o v e r m a t e r i a l , whereas t h e q u a l i t y i s a f u n c t i o n o f r e f u s e c o m p o s i t i o n and l a n d f i l l age.
B i o l o g i c a l treatment has been found t o be s u p e r i o r i n
t r e a t i n g h i g h - s t r e n g t h l e a c h a t e from r e c e n t l y d e p o s i t e d r e f u s e , w h i l e p h y s i c a l - c h e m i c a l methods y i e l d b e t t e r r e s u l t s t r e a t i n g the l o w e r - s t r e n g t h leachate
(produced by more s t a b i l i z e d
fills) . 2
N e a r l y a l l l e a c h a t e t r e a t a b i l i t y s t u d i e s have so f a r been performed a t room t e m p e r a t u r e s .
In s i t u , a l e a c h a t e temperature o f 10-15°C i s
more l i k e l y t o be observed; hence, i t i s o f g r e a t importance t o determine the e f f e c t s t h e s e c o l d e r c o n d i t i o n s have on the b i o l o g i c a l
treatment
process. The purpose o f t h i s i n v e s t i g a t i o n was
t o e v a l u a t e the
treatability
o f h i g h - s t r e n g t h l e a c h a t e s from domestic l a n d f i l l s by a e r o b i c b i o l o g i c a l r e a c t o r s a t temperatures r a n g i n g from 10-25°C.
Due
t o the h i g h i n f l u e n t
c o n c e n t r a t i o n o f p o l l u t a n t s , t h e e f f l u e n t was n o t expected t o s a t i s f y the l o c a l wastewater d i s c h a r g e g u i d e l i n e s ; hence the performance 4
b i o l o g i c a l p o l i s h i n g r e a c t o r s was a l s o o f To a c c o m p l i s h t h e s e o b j e c t i v e s ,
of
interest.
semi-continuous,
fill-and-draw,
bench-scale r e a c t o r s were o p e r a t e d a t v a r i o u s l o a d i n g s and
temperatures.
-3-
CHAPTER 2 BACKGROUND
2.1
Sanitary L a n d f i l l
Leachates
Seepage o f water through a l a n d f i l l produces a l i q u i d c a l l e d l e a c h a t e . The name r e f e r s t o the f a c t t h a t water d i s s o l v e s o r i g i n a l components and composition p r o d u c t s as i t e n t e r s the f i l l . moisture a b s o r p t i o n c a p a c i t y , l e a c h a t e may or
When the f i l l
de-
has reached i t s
move i n t o the s u r r o u n d i n g s o i l
s u r f a c e as a s p r i n g , depending on the g e o l o g i c a l c h a r a c t e r i s t i c s o f the The q u a n t i t y o f l e a c h a t e produced
m i l l i o n g a l l o n s per day,
may
depending on such f a c t o r s as l a n d f i l l
any
i t s vegetation.
Although
composition
some l a n d f i l l s may
not
final
generate
l e a c h a t e , i t i s important t o r e c o g n i z e the p o t e n t i a l f o r d o i n g so i f
c o n d i t i o n s a r e changed through,
f o r example, f u t u r e development.
The c o m p o s i t i o n o f l e a c h a t e s from d i f f e r e n t l a n d f i l l s v a r i e s as shown i n T a b l e l may
site.
range from z e r o t o s e v e r a l
and geometry, h y d r o l o g i c a l c o n d i t i o n s and the c h a r a c t e r i s t i c s o f the s o i l c o v e r and
strata
range from
5
.
The Chemical
Oxygen Demand (COD)
"not d e t e c t a b l e " t o 90,000 mg/L.
The
widely
concentration
s t r e n g t h o f the
l e a c h a t e depends, among o t h e r f a c t o r s , on the degree o f s o l i d waste s t a b i l i z a t i o n within the f i l l .
The main s t a b i l i z a t i o n p r o c e s s i s
anaerobic b i o l o g i c a l degradation.
T h i s p r o c e s s i s dependent on
the
a v a i l a b i l i t y o f water; hence, l a n d f i l l s i n wet c l i m a t e s s t a b i l i z e fast
relatively
(10-20 y e a r s ) , and c o n c o m i t a n t l y produce l a r g e volumes o f l e a c h a t e .
the o t h e r hand, f i l l s
i n a r i d r e g i o n s may
Chian and D e W a l l e and age of f i l l method.
2
remain e s s e n t i a l l y unchanged f o r decades.
suggest the use of COD,
t o determine
COD/TOC, BOD /COD, 5
t h e most e f f e c t i v e o r g a n i c removal
treatment
Table 2 shows t h e c h a r a c t e r i s t i c s of young, medium and o l d
l a n d f i l l s a s suggested
by Chian and
On
DeWalle . 2
-4-
TABLE 1 COMPOSITION OF TYPICAL LEACHATES
Range o f V a l u e s o r C o n c e n t r a t i o n s * ( L a n d f i l l s and T e s t L y s i m e t e r s )
Parameter BOD
5
COD T o t a l Carbon T o t a l Organic Carbon Total Solids Total V o l a t i l e Solids Total Dissolved Solids Acidity Alkalinity
- 55 000
0
- 90 000
715 715
3
0 0 0 0 5 0 34 0 0 0.2 0 165 0.06 0 0 0 0 0.01 0 2.8 0 1 0 0 0 0 3.7
PH Tannin-like
compounds
(chloroplatinate)
Odour * A l l values
—
-
22 350 22 350
1 000 _ 45 000 1 000 - 23 157 0 - 42 300 0 0
Aluminum Arsenic Barium Beryllium Calcium Cadmium Chloride Chromium Copper Iron Lead Magnesium Manganese Mercury Molybdenum Nitrogen - t o t a l - NH Nickel Phosphorus - t o t a l Potassium Sodium Sulphates Sulphides Titanium Vanadium Zinc
Colour
9
78 0
- 9 560 - 20 900 _
--
-
-
----
-
-
-
--
122 11.6 5.4 0.3 4 000 0.19 2 800 33.4 10 5 500 5.0 15 600 1 400 0.064 0.52 2 406 1 106 0.80 154 3 770 7 700 1 826 0.13 5.0 1.4 1 000
- 8.5
-
1 278
- 12 000
not d e t e c t a b l e
to terrible
except those f o r pH, c o l o u r and odour a r e i n mg/L.
TABLE 2 PROPOSED RELATIONSHIP BETWEEN COD/TOC,.BOD^/COD, ABSOLUTE COD, AND AGE OF F I L L TO EXPECTED EFFICIENCIES OF ORGANIC REMOVAL FROM LEACHATE
COD/TOC
BODv/COD
Age o f F i l l
COD, i n milligrams per l i t r e
Biological Treatment
Chemical precipitation Cmass l i m e dose)
Chemical Oxidation Ca (C10)
2
°3
Reverse Osmosis
Activated Carbon
Ion e x change resins
2
>2.8
>0.5
Young (10,000
Good
Poor
Poor
Poor
Fair
Poor
Poor
2.0-2.8
0.1-0.5
Medium (5 yr-10 y r )
500-10,000
Fair
Fair
Fair
Fair
Good
Fair
Fair
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