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UPGRADING A BREWERY WASTEWATER PRETREATMENT FACILITY FOR
THE CITY OF WINSTON-SALEM
C.D. Maloney<, R.M. Stein*, and T.D. Cornett**
INTRODUCTION
The malt beverage brewing industry produces in excess of 60 bil gal of waste- water annually. A large percentage of this wastewater discharges into munici- pal wastewater treatment facilities. Typical raw waste loads for the malt beverage brewing industries are presented in Table 1. demanding materials and suspended solids generated requires a high level of treatment. This treatment is normally provided either at the brewery or at a municipal wastewater treatment plant. This paper reviews the treatment system and operation program developed by the City of Winston-Salem, North Carolina, for treatment of a brewery wastewater at the Archie Elledge Waste Treatment facility. The City of Winston-Salem operates a 36 mgd activated sludge waste treatment plant. The treatment plant provides both primary and secondary treatment. Primary treatment consists of bar screens, grit removal, and primary clarification; while secondary treatment consists of four 200-ft diameter trickling filters followed by activated sludge and chlorination. Excess biological and raw primary sludges are anaerobically digested and subsequently dewatered on sand drying beds. The dried sludge is applied directly to farm lands. Gas produced by anaerobic digestion of the sludges is utilized to generate all electrical power requirements. Figure 1 presents a schematic illustration of the Archie Elledge Waste Treatment Plant.
The quantity of oxygen
Operational problems were experienced at the Archie Elledge plant, because of an organic overloading of the secondary treatment system. The City and and its consultant, AWARE, Inc., evaluated alternatives to reduce the organic load to the secondary treatment facilities. The results of this evaluation indicated that pretreatment of the brewery waste was the most practical approach to the problem. Pretreatment of the brewery waste was selected for two major reasons.
1. The City of Winston-Salem has a number of industries which dis- charge concentrated wastes into the treatment system. Most indus- trial wastes are combined with domestic waste and diluted before reaching the treatment plant. The brewery waste discharges into a separate outfall with only 100 private residences and thus arrives at the treatment plant without significant dilution. Thus, the brewery waste was segregated and arrived at the plant as a concentrated stream.
- *Associated Water and Air Resources Engineers, Inc., Nashvi-lle, Tennessee **City of Winston-Salem, Winston-Salem, North Carolina
231
w7
232
TABLE 1. TYPICAL RAW WASTE CHARACTERISTICS FROM MALT BEVERAGE PRODUCTION
Brewing Industry Mean Raw Waste Loads per Bbl of BeerC Average Range
Raw Waste Volume 2649 5-30280 m 3 971,46R/bbl beerb
Raw Waste BOD b 1400-2000 mg/ la 1.37 kg/bbl beer (1622 mg/l)
b Raw Waste Suspended Solids 500-700 mg/la .56 kg/bbl beer
(772 mg/l)
Federal Guidelines, State and Local Pretreatment Guidelines, Construction Grants Program Information, EPA-430/9-76-017~, January 1977,
a
bEPA Technology Transfer Series, Capsule Report 6, Pollution Abatement in a Brewing Facility, Prepared by U,S, EPA,
One barrel contains 117,18 liters, C
2. The potential for developing filamentous organisms could be re- duced by pretreatment of a predominatly carbohydrate brewery waste prior to the activated sludge system.
Table 2 presents a summary of the brewery raw wastewater characteristics as it enters the Elledge plant. This discharge includes the brewery, the brewery container manufacturing plant wastes, and a small domestic con- tribution. The brewery wastestream comprises approximately 35 percent of the total BOD loading to the waste treatment plant and approximately 10 per- cent of the total plant flow.
The pretreatment system was developed in two phases. The initial phase of the brewery pretreatment facilities, constructed in 1971, consisted of a 1.33 mil gal aerated lagoon with an installed horsepower level of 360. The system was designed to treat a flow of 2.5 mgd. The effluent soluble BOD from the basin averaged 450 mg/l with a volatile suspended solids level of approximately 850 mg/l.
In 1977, it was decided to expand and upgrade the pretreatment facilities to accommodate the increased loadings and produce an effluent with a solu- ble BOD level of less than 350 mg/l. Discussions with brewery personnel indicated that with increases in production and expansion of the brewery facilities, the average brewery wastewater flow could be expected to be 3.5 mgd with a BOD concentration of approximately 2,000 mg/l.
233
TABLE 2. SUMMARY OF BREWERY R A W WASTEWATER CHARACTERISTICS
Monthly Average Values
1976 1977 (a' Parameter
Min. Avg. Max.
BOD 1,011 1,509 2,103
ss 269 546 739
NO3-N
ALK
3.8"' 3.9 (c' 4.1(c'
395 ('' 405 414")
pH, u n i t s 5.7 6.9 7.4
Min . 945
361
20
1 .4
0.4
209
6.9
Avg . Max
1 ,378 1,777
526 773
27.8 46
4.4 1 2
3.0 15 .5
320 402
7.5 7.7
a
bExpressed as mg/l of C2C03.
A l l u n i t s are mg/l except as noted .
C Data shown f o r November 1976 and December 1976 only .
P r i o r t o upgrading t h e t r e a t m e n t f a c i l i t i e s , t h e o p e r a t i o n of t h e e x i s t i n g p r e t r e a t m e n t system w a s reviewed. The o b j e c t i v e of t h i s review w a s t o d e f i n e problems i n t h e o p e r a t i o n of t h e brewery p r e t r e a t m e n t system s o t h a t s o l u t i o n s t o t h e s e problems could b e i n c o r p o r a t e d i n t h e upgraded f a c i l i t y . A d i s c u s s i o n of some of t h e o p e r a t i o n a l problems a s s o c i a t e d w i t h t h e t r e a t m e n t of brewery wastewaters i s p r e s e n t e d as f o l l o w s .
OPERATIONAL CONSIDERATIONS
S i g n i f i c a n t v a r i a t i o n s i n b o t h t h e q u a n t i t y and q u a l i t y of brewery waste- waters r e s u l t because of b a t c h p r o c e s s i n g and t h e s e a s o n a l f l u c t u a t i o n s i n product ion schedules . F i g u r e 2 p r e s e n t s t h e c h r o n o l o g i c a l v a r i a t i o n s of t h e average monthly BOD and suspended s o l i d s l o a d i n g t o t h e E l l e d g e t r e a t m e n t p l a n t from t h e brewing f a c i l i t i e s . Peak product ion , as noted by i n c r e a s e d l o a d i n g s t o t h e p l a n t , w a s d u r i n g A p r i l through August, which i s c o n s i s t e n t w i t h h i s t o r i c a l d a t a . These s e a s o n a l v a r i a t i o n s are s i g n i f i c a n t i n t h e o p e r a t i o n of waste t r e a t m e n t f a c i l i t i e s from t h e s tand- p o i n t o f :
2 34
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2 35
1. E q u a l i z a t i o n must b e provided o r t h e f a c i l i t y must b e s u f f i - c i e n t l y l a r g e t o accommodate t h e peak l o a d i n g s .
2 . The h i g h l o a d i n g s i n c r e a s e oxygen demand on t h e t r e a t m e n t sys- t e m d u r i n g t h e summer months.
S i g n i f i c a n t d i u r n a l load v a r i a t i o n s are found i n t h e brewery wastewater. F i g u r e 3 p r e s e n t s t h e d i u r n a l v a r i a t i o n i n chemical oxygen demand (COD) observed over a 48-hour p e r i o d . The d i u r n a l v a r i a t i o n s of COD d u r i n g t h i s p a r t i c u l a r p e r i o d ranged from 1,100 mg/l t o 2,600 mg/l. F i g u r e 4 shows t y p i c a l d i u r n a l f low p a t t e r n s from t h e brewery. Extreme d i u r n a l v a r i a t i o n s of pH are exper ienced due t o t h e b a t c h o p e r a t i o n of t h e brewing p r o c e s s and t h e n e c e s s i t y of thoroughly c l e a n s i n g t h e equipment w i t h caus- t i c wash s o l u t i o n s between brews. F i g u r e 5 shows t y p i c a l v a r i a t i o n s of t h e wastewater pH d u r i n g a 24-hr p e r i o d and i n d i c a t e s t h e s e v e r i t y and d u r a t i o n of t h e pH o s c i l l a t i o n s .
The wastewater as r e c e i v e d from t h e brewery does n o t c o n t a i n a s u f f i c i e n t q u a n t i t y of n i t r o g e n t o accommodate b i o l o g i c a l o x i d a t i o n . It i s , t h e r e - f o r e , n e c e s s a r y t o supply a supplementa l n i t r o g e n s o u r c e t o meet t h e n u t r i e n t requi rements of t h e microorganisms. Liquid a g r i c u l t u r a l n i t r o g e n (30 p e r c e n t t o t a l n i t r o g e n c o n t e n t ) i s purchased and metered i n t o t h e a e r a t i o n b a s i n . The c o s t of t h e n i t r o g e n supplement amounts t o approxi- mately $36,000 p e r y e a r . The v a r y i n g o r g a n i c load of t h e brewery waste- stream r e q u i r e s c o n s t a n t moni tor ing of t h e n i t r o g e n a d d i t i o n f a c i l i t i e s t o e n s u r e t h a t an adequate n i t r o g e n l e v e l i s maintained.
Problems have been exper ienced because of e x c e s s i v e d i s c h a r g e s i n t o t h e t r e a t m e n t system. Three major o r g a n i c d i s c h a r g e s i n c l u d i n g d e x t r o s e and corn syrup have occurred a t t h e brewery because of equipment m a l f u n c t i o n s and r u p t u r e d p i p e s . mate ly 22,500 kg of d e x t r o s e e n t e r i n g t h e t r e a t m e n t f a c i l i t y . This o r g a n i c l o a d t o t h e a e r a t i o n b a s i n caused a r a p i d d e p l e t i o n of t h e d i s s o l v e d oxygen level i n t h e p r e t r e a t m e n t b a s i n and subsequent r e d u c t i o n of t r e a t m e n t e f f i c i e n c y . p l a n t proper ' w i t h a n u l t i m a t e d e t e r i o r a t i o n of f i n a l e f f l u e n t q u a l i t y . It took approximately t h r e e days f o r t h e system t o r e c o v e r from t h i s shock.
The l a r g e s t of t h e d i s c h a r g e s r e s u l t e d i n approxi-
T h i s r e s u l t e d i n h i g h o r g a n i c l o a d s b e i n g t r a n s f e r r e d t o t h e
The d i s c h a r g e of o i l and g r e a s e i n t o t h e c o l l e c t i o n system i s a n o t h e r pro- blem. The o i l and g r e a s e o r i g i n a t e from t h e metal c a n s manufactur ing faci- l i t y . Although no i n h i b i t i o n s t o t h e b i o l o g i c a l systems have been observed due t o t h e o i l and g r e a s e s p i l l s , f o u l i n g of t h e c o l l e c t i o n system and pumping f a c i l i t i e s has occurred . T h i s r e s u l t s i n a l a r g e manpower expendi- t u r e i n c l e a n i n g t h e t r a n s p o r t f a c i l i t i e s .
A f r e q u e n t l y o c c u r r i n g problem encountered i n t h e t r e a t m e n t of brewery wastewaters is t h a t of foam on t h e a e r a t i o n b a s i n s . deep have formed on t h e a e r a t i o n b a s i n s and t h i s i s u n d e s i r a b l e f o r s e v e r a l reasons . b a s i n s . o u t of t h e b a s i n . odor problem.
Foam l a y e r s 4 - 5 i n .
The foam rises and f lows o u t and onto t h e ground sur rounding t h e The b i o s o l i d s become ent rapped i n t h e foam and are a l s o c a r r i e d
This c a u s e s u n s a f e c o n d i t i o n s and p r e s e n t s a p o t e n t i a l A d d i t i o n a l l y , i f t h e foam does n o t overf low t h e b a s i n s , t h e
2 36
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z 0’ z 0”
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NOTE: EACH UNIT ON THE GRAPH REPRESENTS 1 mgd
FIG. 4 TYPICAL DAILY FLOW PATTERNS FROM THE BREWERY
238
FIG. 5 TYPICAL DIURNAL pH VARIATIONS
2 39
s o l i d s have a tendency t o accumulate and form c r u s t l a y e r s on t o p of t h e foam, a g a i n r e s u l t i n g i n odor problems.
SIGNIFICANT DESIGN CONSIDERATIONS
Increased l o a d i n g s on t h e E l l e d g e t r e a t m e n t p l a n t a g a i n overloaded i n t h e p l a n t i n 1976 ; t h e r e f o r e , i t w a s dec ided t o expand t h e brewery pre- t r e a t m e n t p r o c e s s . This would r e l i e v e t h e p l a n t of t h e i n c r e a s e d brewery l o a d i n g s and a l l o w t h e p l a n t t o receive and accommodate i n c r e a s e d l o a d s from o t h e r i n d u s t r i a l c o n t r i b u t o r s . The o b j e c t i v e s i n upgrading t h e brewery p r e t r e a t m e n t system were:
1. To reduce t h e incoming o r g a n i c waste l o a d from t h e brewery.
2 . To p r o v i d e c a p a b i l i t i e s w i t h i n t h e system t o dampen and e q u a l i z e t h e q u a n t i t y and q u a l i t y of t h e brewery wastewaters.
3. To i n c l u d e t h e f l e x i b i l i t y of o p e r a t i n g t h e two-basin system i n e i t h e r a series o r p a r a l l e l mode.
4 . To examine t h e f e a s i b i l i t y of u t i l i z i n g a n a e r o b i c d i g e s t e r s u p e r n a t a n t as a n i t r o g e n source .
P i l o t a e r a t e d lagoon s t u d i e s w e r e performed and f u l l - s c a l e o p e r a t i n g d a t a were e v a l u a t e d t o develop t h e p r o c e s s d e s i g n c r i t e r i a and t h e u s e of d i g e s t e r s u p e r n a t a n t as a n i t r o g e n source . The r e s u l t s of t h e s e s t u d i e s are summarized i n Table 3 . Table 4 p r e s e n t s t h e average c h a r a c t e r i s t i c s of t h e d i g e s t e r s u p e r n a t a n t . The r e s u l t s of t h e s t u d i e s i n d i c a t e d t h a t an a e r a t e d lagoon could p r o v i d e h igh levels of o r g a n i c removal. The d i g e s t e r s u p e r n a t a n t proved an e f f e c t i v e n u t r i e n t source . An e f f l u e n t s o l u b l e BOD of less than 350 mg/l could c o n s i s t e n t l y b e achieved w i t h t h e a d d i t i o n of d i g e s t e r s u p e r n a t a n t .
TABLE 4 . SUMMARY OF ANAEROBIC DIGESTER SUPERNATANT CHARACTERISTICS ARCHIE ELLEDGE WASTE TREATMENT PLANT
~~
Parameter Value
COD, t o t a l (mg/l) 14 ,891
S o l i d s ( p e r c e n t ) 1 .70
V o l a t i l e S o l i d s ( p e r c e n t ) 0 ,80
NH3-N (mg/l) 245,
Flow m 946.25
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Tests were conducted t o de te rmine t h e rate of oxygen t r a n s f e r i n t o t h e brewery wastewater re la t ive t o t h e oxygen t r a n s f e r ra te i n t o t a p water ( a l p h a t e s t s ) . t h e c o u r s e of t h e s t u d y . These r e s u l t s are summarized i n Table 5. These v a l u e s , 0.6 t o 0 . 7 , are cons idered r e a s o n a b l e and were used f o r des ign .
Several series of a l p h a tests were performed through
TABLE 5. SUMMARY OF OXYGEN TRANSFER ANALYSES
Sample Loca t ion and Date ( a )
T e s t Speed RPM Alpha F a c t o r
Basin E f f l u e n t 150 (March 1976) 225
300
Basin E f f l u e n t (March 1977)
Basin I n f l u e n t (March 1977)
100 200 288
100 200 288
0.52 0.15 0.33
0.66 0.67 0.64
0.48 0.56 0.58
a A l l v a l u e s c o r r e c t e d t o 20°C.
The microorganisms u t i l i z e oxygen f o r b i o l o g i c a l r e s p i r a t i o n . For brewery waste t r e a t m e n t , (approximately 2.0 t o 5.0 g 0 /g b a s i n v o l a t i l e so l ids -day 2 i s r e q u i r e d ) . T h i s i s v e r y h i g h when compared t o rates f o r a t y p i c a l act i - v a t e d s l u d g e system of between 0.1 t o 0.8 g 0 2 / g b a s i n v o l a t i l e so l ids -day .
These two f a c t o r s , low t r a n s f e r rates and h i g h oxygen uptake rates, r e s u l t i n a l a r g e horsepower i n p u t t o t h e b a s i n , approximately 270 hp/mi l g a l of b a s i n volume. 150 hp/mi l g a l of b a s i n volume.
T y p i c a l a c t i v a t e d s l u d g e horsepower levels range from 100 t o
DESIGN CONSIDERATIONS FOR OPERATIONAL FLEXIBILITY
U t i l i z i n g t h e r e s u l t s from t h e bench-scale tests, and d a t a g a t h e r e d from t h e o p e r a t i o n of t h e f u l l - s c a l e system, a p r o c e s s d e s i g n w a s developed f o r t h e proposed expansion. The d e s i g n summary f o r t h e expanded f a c i l i t i e s i s p r e s e n t e d i n Table 6 .
F i g u r e 6 p r e s e n t s a schemat ic i l l u s t r a t i o n of t h e expanded f a c i l i t i e s employed f o r t h e p r e t r e a t m e n t of t h e brewery wastewaters. f i r s t p laced on l i n e i n 1971 and Basin 2 w a s p u t i n t o service i n October 1977. T o t a l i n s t a l l e d horsepower f o r b o t h b a s i n s i s 900.
Basin 1 w a s
242
8 ! z E
w
I- <
w
n? c
w e
p.
m
243
TABLE 6. DESIGN SUMMARY
Parameter Value
AERATED LAGOON
3 Design Flow, m
I n f l u e n t BOD, mg/l
E f f l u e n t BOD, mg/l
Basin Volume, m 3
E x i s t i n g Basin New Basin
Aera t ion Horsepower, hp
E x i s t i n g Basin New Basin
3 Surge Capac i ty , m
E x i s t i n g Basin New Basin
Ni t rogen Requirements , kg/day
Maximum Average
13,247.5
2,000
350
5,034.05 7,570
360 540
0 2,460.25
1 ,314 1,026
The problem of f l u c t u a t i n g wastewater f low and load w a s addressed i n t h e p rocess des ign . Approximately 0.65 m i l g a l of s u r g e c a p a c i t y w a s i nco r - po ra t ed i n t o t h e des ign of t h e new b a s i n . The s u r g e c a p a c i t y c a l c u l a - t i o n s were p r e d i c a t e d on p rov id ing a d d i t i o n a l e q u a l i z a t i o n f o r t h e a c t i - v a t e d s l u d g e b a s i n i n t h e p l a n t p rope r . The s u r g e c a p a c i t y w a s ach ieved by c o n s t r u c t i n g a v a r i a b l e l e v e l d i s c h a r g e w e i r i n t h e new b a s i n . Using high-speed, f l o a t i n g a e r a t o r s a l lows t h e water l e v e l t o b e v a r i e d approxi- mate ly 2.5 f e e t (0.65 mg).
I n t h e des ign of t h e new f a c i l i t i e s , f l e x i b i l i t y w a s i n c o r p o r a t e d t o a l low t h e o p e r a t i o n of t h e two b a s i n s i n e i t h e r a p a r a l l e l o r series mode. Basin 1 is ope ra t ed on a flow-through b a s i s , w h i l e Basin 2 can b e ope ra t ed a t v a r y i n g l e v e l s .
It w a s dec ided t o u t i l i z e d i g e s t e r s u p e r n a t a n t as a n i t r o g e n source . l i z i n g t h e d i g e s t e r s u p e r n a t a n t o f f e r s s e v e r a l advantages . purchase ammonia w a s e l imina ted r e s u l t i n g i n a $35,00O/yr sav ings . s u p e r n a t a n t c h a r a c t e r i s t i c a l l y has pH i n t h e r ange of 6 .5 t o 6.8. s l i g h t l y a c i d i c pH coupled w i t h an a l k a l i n i t y v a l u e of approximate ly 2,000 mg/ l , as CaC03, h e l p s t o b u f f e r t h e f l u c t u a t i n g pH r e c e i v e d from
U t i - The need t o
The Th i s
244
the brewery. Additionally, the basin alkalinity as CaCO has increased from approximately 225 mg/l to approximately 450 mg/l. greater degree of protection from pH upsets. structed and attendant piping installed (approximately 1,080 m at 20-cm diameters).
3 This affords a much A pumping station was con-
The causes of foaming were evaluated and it was determined that the foaming phenomenon results because of:
1. The high agitation levels within the basin (approximately 270 hp/mil gal.
2 . Large volume of caustic wash solutions used at the brewery.
3. The foaming nature of the beer product itself. Operating experience has found that the foam can best be controlled with the use of commercially available defoaming agents.
The problem of oil and grease discharges was resolved through the coopera- tion of both the City and the brewery. The brewery has implemented pre- treatment to capture oils.
TREATMENT PLANT PERFORMANCE
The new basin has been on stream since October 1977. Several mechanical difficulties prevented full-scale operation prior to February 1978. The first several weeks of operation are encouraging. Figure 7 presents a chronological summary of various operational parameters. These data indi- cate that the basin is consistently producing an effluent with a soluble BOD level of less than 350 mg/l. Normally, effluent soluble BOD is in the range of 200 mg/l. These data reflect parallel operations of the two basins. Operation in a series mode has not been initiated.
The treatment of brewery wastewaters in a municipal waste treatment plant presents some particular problems that must be addressed through design and operation of the facility. The City of Winston-Salem has addressed this problem and has developed a program to successfully treat brewery wastes .
2 45
. . .
2,500
2,OOo
5 E a- 1,500
5i 1 ,ooo
500
2,500
2,OOo
s a- E 1,500
8 1 ,m
500
2,000
= 1>00 i?
5 1,OOo
mi
I
ul
500
I I I I I I 1 I
M INFTOTAL e-* EFF SOLUBLE
-
-
SUPERNATANT
5 10 15 20 25 2 7 12 17
FEB MARCH FIG. 7 CHRONOLOGICAL VARIATION OF PRETREATMENT
SYSTEM PERFORMANCE
246
