GROUP lj PHASE I
SUPPLEMENT TO DEVELOPMENT DOCUMENT FOR
EFFLUENT LIMITATIONS GUIDELINES AND
EW SOURCE PERFORMANCE STANDARDS FOR THE
CORN VET MIIUNG SUBCATEGORY
GRAIN PROCESSING
SEGMENT OF THE
GRAIN MILLS
POINT SOURCE CATEGORY
WGUST 1975
i "$ EIWIfOffNTAL PROTECTION AGENCY
WASHINGTON, D, C. 20460
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f >
f *
S*
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SUPPLEMENT TO DEVELOPMENT DOCUMENT
for
EFFLUENT LIMITATIONS GUIDELINES
and
NEW SOURCE PERFORMANCE STANDARDS
for the
CORN WET MILLING SUBCATEGORY
GRAIN PROCESSING SEGMENT OF THE
GRAIN MILLS POINT SOURCE CATEGORY
Russell E. Train
Administrator
James L. Agee
Assistant Administrator
for
Water and Hazardous Materials
Allen Cywin
Director, Effluent Guidelines Division
Richard V. Watkins
Project Officer
August 1975
Effluent Guidelines Division
Office of Water and Hazardous Materials
U.S. Environmental Protection Agency
Washington, D. C. 20460
,.*
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TABLE OF CONTENTS
SECTION PAGE
I CONCLUSIONS 1
II RECOMMENDATIONS 3
III INTRODUCTION 5
A. Court Findings 5
B. Court Directives 6
C. Purpose of this Report 6
D. Organization of this Report 6
E. Sources of Data 7
IV EFFECTIVENESS OF BIOLOGICAL TREATMENT 11
A. Municipal Wastewater Applications 11
B. Industrial Wastewater Applications 12
C. Corn Wet Milling Industry 13
1. CPC - Pekin, Illinois 19
2. CPC - Corpus Christi, Texas 21
3. American Maize - Hammond, Indiana 22
4. Clinton Corn Processing Company -
Clinton, Iowa 23
5. Pretreatment Facilities 23
D. Summary 24
V IN-PLANT CONTROLS 25
VI EVALUATION OF FILTER TECHNOLOGY 27
A. Treatment of Water Supplies 27
B. Filtration of Treated Wastewater 28
C. Expert Opinion on Applicability of
Filtration to Corn Wet Milling Wastes 39
D. Siunmary 40
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TABLE OF CONTENTS - (cont)
SECTION
VII CLINTON CORN WASTE TREATMENT 43
A. Background and Pollution Abatement
Efforts 43
B. Evaluation of Treatment Plant
Performance 44
C. Performance of Deep Bed Filters 46
D. Summary 46
VIII ABILITY OF CORN WET MILLS TO MEET NEW SOURCE
PERFORMANCE STANDARDS 51
A. Design Criteria 51
B. Waste Treatment Components 52
C. Performance of Waste Treatment
Facilities 53
D. Effects of Product Mix 58 56
E. Costs of Compliance with New Source
Performance Standards 57
IX NONWATER QUALITY ASPECTS 59
X SUMMARY 61
REFERENCES 69
APPENDIX A 75
ill
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SECTION I
CONCLUSIONS
An extensive review of available data on the application of
activated sludge and deep bed filtration for treatment of various
wastewaters was conducted. Sources of data included the technical
literature, field inspections, special consultants and expert
opinions, corn wet milling companies, and equipment manufacturers.
The data unequivocally and unmistakably substantiate the fact that
high strength biodegradable organic wastes, such as those generated
by corn wet mills, can be successfully treated with biological
treatment processes,, particularly complete mix ac-civated sludge.
With proper design and operation of treatment facilities, a stable
high quality effluent can be attained on a reliable and sustained
basis.
i
Ample evidence also exists to demonstrate that deep bed filtration
is being applied successfully outside the corn wet milling industry.
Filtration is used to treat potable water supplies, effluent from
domestic sewage plants, and biologically treated effluents from many
industrial waste treatment operations. Filtration can be applied to
the corn wet milling industry, and, in fact, is being successfully
employed by one company in the industry, despite inadequacies with
in-plant controls and the preceding biological treatment process.
The treatment of variable, high strength wastewaters is not an
enigma in sanitary engineering and pollution control practice.
Indeed, numerous treatment applications have been made in many
industries similar to corn wet milling, all with successful results.
Not only have high degrees of pollutant removal been achieved
through biological treatment, but additional pollutant reductions or
effluent "polishing" have been demonstrated with filtration. The
performance of these measures with corn wet milling wastes can be
reasonably and unmistakably predicted.
On the basis of this study, it is concluded that the New Source Per-
formance Standards as promulgated can be met by applying the
technology prescribed for the corn wet milling subcategory in the
Development Document for the Grain Processing Industry. Data on
treatment of similar wastes strongly indicate that the standards
quite probably can be achieved through biological treatment without
filtration. Deep bed filtration, as with other "polishing" devices,
provides additional assurance of maintaining a high quality effluent
and minimizes or reduces the effects of biological treatment plant
upsets. Such upsets can usually be attributed to poor in-plant
control, faulty design, improper operation and human error.
Polishing mechanisms such as filtration reduce the effects of such
circumstances and are well demonstrated in achieving high quality
effluent on a long-term basis.
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The costs required for new corn wet mills of various sizes to meet
the New Source Performance Standards were reevaluated and are
indicative of current pollution control technology. These costs are
based on January 1975 dollar values and include waste treatment
facilities and necessary in-plant controls or cooling system
designs. Evaluation of nonwater quality aspects of applying the
recommended technology indicated that energy, air pollution, and
solid waste impacts will be minimal.
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SECTION II
RECOMMENDATIONS
Based on an extensive review of technical data, it is recommended
that the _New Source Performance Standards for the Corn Wet Milling
Subcategory be implemented as promulgated on March 20, 197U. As the
data reviewed demonstrate, new plants employing best available
demonstrated control technology can readily achieve these standards.
The New Source Performance Standards as recommended are as follows:
BQD Suspended Solids ]DH
kg/kkg 0.357 0.179
Ibs/MSBu 20.0 10.0
units 6-9
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SECTION III
INTRODUCTION
On May 5r 1975 the U.S. Court of Appeals for the Eighth Circuit,
issued its decision on Effluent Limitations Guidelines, New Source
Performance Standards, and Pretreatment Standards for the Corn Wet
Milling Subcategory of the Grain Milling Industry. The Court
determined that it had no jurisdiction over Effluent Limitation
Guidelines; but indicated this is a matter to be decided by the
District Court. The Court did find it had jurisdiction over New
Source Performance and Pretreatment Standards.
A. COURT FINDINGS
In reviewing the New Source Performance Standards for the Corn Wet
Milling Subcategory, the court noted the New Source limitations are
identical to the 1983 guidelines. The 1983 guidelines assume the
technology available to meet the 1977 guidelines will be
supplemented by additional technology in 1983. After reviewing the
basis for the 1977 guidelines, the Court concluded that the
recommended 1977 technology, when employed in a new corn wet milling
plant, would enable that plant to comply with the 1977 guidelines.
However, the Court concluded that the record does not support EPA's
determination that technology is available to meet the New Source
Performance Standards. This technology, in the Court's view, would
be required to remove an additional 30 pounds of BOD and 60 pounds
of suspended solids per MSBu (0.536 kg/kkg BOD and 0.714 kg/kkg TSS)
beyond the 1977 guideline limits of 50 pounds per MSBu (0.893
kg/kkg) of both BOD and suspended solids. The Court felt that,
according to the record, deep bed filtration was being called on to
provide most of the incremental reduction in BOD and suspended
solids. They concluded that within the record there are no concrete
data, test results, literature, or expert opinion in support of the
"prediction" that filtration will permit a new corn wet mill to meet
the New Source Performance Standards. To base standards on transfer
technology, the Court stated that EPA must: 1) determine that the
technology is available, 2) determine that the technology is
transferable, and 3) make a reasonable prediction that the
technology will be capable of removing the increment required by the
New Source Performance Standards.
The Court also concluded that the costs required in adopting the New
Source Performance standards were not covered adequately in the
record. Two problems were cited. First, EPA did not project
separate capital and operating costs for control technology
implemented at new plants. Second, EPA used 1971 prices in making
cost estimates, despite the fact that more current data were
available.
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B. COURT DIRECTIVES
On the basis described above, the Court remanded the New Source Per-
formance Standards to EPA. Their directive was that EPA, within 120
days, either furnish support for the present New Source Performance
Standards or establish new standards.
C. PURPOSE OF THIS REPORT
The purpose of this report is to review the basis for the Corn Wet
Milling New Source Performance Standards, review the technology
recommended to meet these standards, and recommend further action to
EPA in following the Court's directives. This report presents a
detailed evaluation of the treatment technologies identified to meet
the New Source Performance Standards: namely, activated sludge
followed by deep bed filtration, although other technologies or even
activated sludge alone may be capable of meeting the standards.
Other technologies were briefly reviewed and may be applied, but the
identified technologies cited above clearly represent the most
practical and common approach to treatment of corn wet milling
wastes.
The Court's conclusion that deep bed filtration was being called
upon to remove an incremental 30 Ib of BOD and 40 lb of TSS per MSBu
(0.536 kg/kkg BOD and 0.71U kg/kkg TSS) is not entirely correct. An
analysis of existing plants and their capabilities of meeting 1977
and 1983 Effluent Guidelines cannot be extrapolated directly to new
corn wet mills. New m.~tll in-plant controls will provide raw waste
load reduction and stabilization and thus will greatly contribute to
treatment plant performance. This report logically develops
attainable effluent levels from new corn wet mills employing best
available control technology and compares these levels with the
present New Source Performance standards.
D. ORGANIZATION OF THIS REPORT
This report is divided into ten sections. Section I summarizes the
conclusions of the report. Recommendations to EPA based on the
findings documented herein are presented in Section II. Section III
summarizes the decision by the U.S. Court of Appeals, Eighth
Circuit, and reviews the sources of data used to prepare this
document. Section IV is an evaluation of the effectiveness of
biological treatment systems, particularly the activated sludge
process, handling corn wet milling wastes and other high c; .rength
organic wastes. In-plant control technologies applicable ;o new
corn wet mills are discussed in Section V. Section VI evaluates
deep bed or tertiary filtration, a technology for reducing BOD and
suspended solids levels in secondary effluents. A discussion of
Clinton Corn Processing Company"s (Clinton, Iowa) waste treatment
facilities is presented in Section VII. Clinton employs much of the
end-of-pipe treatment technology recommended to meet New Source
Performance Standards, including filtration, although the plant is
subject to operational limitations as discussed in the section* In
Section VIII, predicted performance of new plants is presented.
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Model plants with accompanying treatment facilities are outlined.
Effluent levels are predicted in terms of pound of pollutant per
unit quantity of raw material. Associated costs to meet New Source
Performance Standards are also given. Section IX evaluates the non-
water quality aspects of compliance with New Source Performance
standards, including energy requirements, air pollution, and solid
waste disposal. Section X is a summary of the findings of this
study.
E. SOURCES OF DATA
The detailed information on which this report is based was drawn
from a variety of sources including the literature, field inspec-
tions, special consultants and expert opinion, corn wet milling
companies, equipment manufacturers, and the Environmental Protection
Agency.
An intensive review of the literature was conducted on deep bed fil-
tration with particular emphasis on filtration of biologically
treated effluents. Pertinent findings from this review are cited in
Section VI of this report. The entire Literature Review (1) is
summarized in the supporting documentation contained in a record on
remand which is available for review.
The use of the activated sludge process in municipal and industrial
waste treatment, including corn wet milling was investigated to
document its effectiveness in handling high strength organic waste-
waters. Of particular concern was the application of activated
sludge to industrial wastes similar to those generated by corn wet
milling. These similar wastes include brewing, distilling, malting,
edible oil refining, and wine production. Data were drawn from the
literature and from EPA experience^
Dr. E. Robert Baumann, Anson Marston Distinguished Professor of
Engineering, Iowa State University, was retained to provide
additional technological insight into advanced waste treatment
concepts and applications. Dr. Baumann is one of the leading
authorities on filtration of secondary treatment plant effluents,
and is the author of numerous papers and textbooks in sanitary and
environmental engineering.
Dr. Raymond C. Loehr, Professor of Engineering, Cornell University,
was also consulted in the development of this report. Dr. Loehr is
a recognized expert in the treatment and disposal of high strength
organic wastes.
In addition, Dr. Charles M. Cook, Technical Advisor to the Director
of Monitoring and Data Support Division of EPA, reviewed and
evaluated the data and statistics developed in this study.
A specific request (2) was made to a number of corn wet milling com-
panies for data regarding:
1. Performance of existing treatment and pretreatment plants
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including related production and product-mix figures, and
treatment costs.
2.
Previous pilot plant studies.
3. Relationship between raw aste characteristics (and treat-
ability) and product mix.
U. Projection of new plant costs, raw waste characteristics,
additional in-plant controls, and power requirements for
the model 30,000, 60,000 and 90,000 bushels/day corn wet
mills.
Responses to some or all of the specific information requested were
made by six companies. Two meetings were held in Washington, D.c.
with representatives of Anheuser-Busch, Inc., CPC International
Inc., and Penick 6 Ford, Ltd.; and one meeting was held with A. E.
Staley Manufacturing Company in Decatur, Illinois.
Several field inspections were conducted including two visits to
Clinton Corn Processing company in Clinton, Iowa and a visit to the
CPC International, Inc. plant in Corpus Christi, Texas. A brief
three-day sampling program was conducted at the Clinton waste treat-
ment plant in an attempt to assess the efficacy of their deep bed
filtration system. visits were also made to the Metropolitan
Sanitary District of Greater Chicago and to Du Page County, Illinois
to discuss their experience with deep bed filtration and to observe
filter installations.
Much information was provided by waste treatment equipment manufac-
turers, particularly regarding filtration. The following filter
manufacturers were contacted and provided data during the study:
Can-Tex Industries
Crane-Cochrane
Dravo Corporation
Ecodyne Corporation
Envirotech
General Filter Company
Hardinge Division, Koppers, Inc.
Hydro-Clear Corporation
Hydromation
Infilco-Degremont
Neptune Microfloc, Inc.
Finally, information was provided by EPA on several pertinent
projects. Specifically, detailed data were supplied on the
treatment of other high strength food wastes, such as those
described in the Development Documents for the Miscellaneous Foods
and Beverages, Fruits and
Vegetables, and Pulp and Paper Point source Categories. Information
was also r«ceived on the EPA Demonstration Project on deep bed
filtration of treated oil refinery wastes.
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All of the information from the above sources was carefully reviewed
and considered in preparing this report. Materials used directly in
the report are referenced herein, and all data are included in the
record which supplements the report.
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Distillery wastes have been shown to be amenable to biological
treatment. Smith (12) reported that 90 percent or better BOD
reduction can be attained with biological treatment processes such
as trickling filters and activated sludge. Raw wastes from
distilleries generally contain 500 to 1000 mg/1 BOD and 50 to 200
mg/1 or more TSS. Effluent data for several distilleries are shown
below (8, 13) :
Range of
Effluent BOD
Concentrations
.mg/1
Range of
Effluent TSS
Concentrat ions
fflSt/i.
20 -
12 -
20 -
10
3 -
40
40
50
15
25 -
12 -
20 -
20 -
10 -
40
70
50
UO
100
On the following page is shown Table 119 from the Miscellaneous
Foods and Beverages Draft Development Document. This table
summarizes the performance of 11 treatment facilities handling
wastes from grain distillers operating stillage recovery systems.
Biological treatment has been successfully applied to bakery and
winery wastewaters. One bakery in the mid-south provides complete
treatment of high strength wastes (14). Treatment includes equali-
zation, dissolved air flotation, trickling (roughing) filter,
activated sludge, and stabilization ponds. High strength wastes
with a BOD concentration in excess of 2000 mg/1 are consistently
reduced to less than 10 mg/1. Treatment performance levels in 1974
were:
Average
Influent
Concentration
Range of
Effluent
Concentrations
BOD
2210
7-9
Percent
Removal
99.6
TSS
1020
6-15
98.5 - 99.4
High strength wastes from winery operations have been shown amenable
to biological treatment processes (15, 16, 17, 18). Wineries gen-
erate medium to high strength organic wastes with BOD levels of 1000
to 2000 mg/1. BOD removals of 90 to 97 percent and suspended solids
removals of 67 to 90 percent are documented in the Miscellaneous
Foods and Beverages Draft Development Document.
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TREATMENT fiYGTI'M SUMMARY
SUBCATEGGRY A22
Plant
85A01
85A02
PercenL Removal
BOD
85A05
85AOJ
8 5 AIT
85A18
85A22
85A27
85A29
Activated Sludge,
Bio Disc.
Aorated Lagoon
Stabilization Pond
Aerated Lagoon,
Stabilization Ponds
Aerated Lagoon,'
Stabilisation Ponds
Activated Sludge
Bio Disc.
Activated Sludge,
Contact Stabilization
Aerated Lagoon,
Stabilization Pond
Aerated Lagoons
Aerated Lagoons
_ Trickling Filters,
- ["Jbabiliaation Ponds
97-5*
37-0
93-3
93-3
91.9
73-8
82.8
3^.3***
97-3
*' Activated S.Ludgo Portion
*» i^cTore Contact .'."taliiJ.iz.atiori Added
*** Ho Clarification after Aeration
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One winery in New York State employed an aerated lagoon system to
treat its wastes (19) . Average raw waste flow is 0.85 mgd (3217 cu
m/day) . Influent BOD ranges from 1000 to 4400 mg/1 and averages
2300 mg/1. Yearly average BOD reductions for a four-year period
were as follows: 1970 - 94 percent, 1971 - 95.2 percent, 1972 -
95.6 percent, 1973 - 94.7 percent. Because of problems with ground-
water intrusion and seasonal fluctuations in effluent quality, the
winery installed an activated sludge treatment system in late 1973.
Data from the first six months of operation (including start-up and
shake-down procedures) indicate an average effluent BOD level of 30
mg/1 and a suspended solids level of 75 mg/1. Data obtained later
in 1974, after stabilization of the treatment process, indicate the
following effluent characteristics (20) :
Effluent Concentrations
Aver age
BOD 18-32 21
TSS 20-54 40
Another example of effective treatment of high strength organic
wastes exists in the frozen specialty product industry. A manufac-
turer in Virginia has treatment facilities consisting of screens,
floatable fat and solids removal, dissolved air flotation, anaerobic
lagoons, trickling filters, contact aeration tanks (activated
sludge), final setting tanks, and chlorination of final effluent.
Based on an analysis of 54 daily samples, BOD and suspended solids
are reduced by 99.7 and 99.3 percent, respectively. The very high
influent raw waste levels (3500 mg/1 BOD and 4500 mg/1 TSS) are
reduced to final effluent levels of 15 mg/1 or less BOD and 35 mg/1
suspended solids. Fat and oily material are reduced from 3000 mg/1
to 1.5 mg/1, representing an overall removal efficiency of 99.9
percent. Maximum daily BOD and TSS values are 27 mg/1 and 119 mg/1,
respectively (21) .
To further evaluate the effectiveness of biological treatment
processes, data from EPA experience with the Fruits and Vegetables
Industry were analyzed (22) . This industry generates a very diverse
array of high strength organic wastes. Within the industry there
are numerous biological treatment systems demonstrating the ability
to successfully treat these wastes without further polishing
techniques such as filtration. EPA accumulated data on 10 activated
sludge systems, two trickling filter systems, and 13 aerated lagoon
systems providing treatment of fruit and vegetable processing
wastes. These exemplary treatment facilities handle biodegradable
wastes from 32 product commodities processed at these plants ,
ranging from corn, tomato products, and sauerkraut to jams, jellies,
and dry beans.
At the fruit and vegetable plants employing activated sludge
systems, raw waste BOD varied from 253 to 4096 mg/1. The activated
sludge systems resulted in long-term BOD reductions from 95.5 to
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99.7 percent. Sustained effluent (annual average) BOD levels ranged
from 8 to 62 mg/1 and averaged 20 mg/1 for all plants.
corresponding effluent suspended solids levels ranged from 10 to 80
mg/1 and averaged 31 mg/1. The new source performance standards for
the corn wet milling industry would require a sustained effluent BOD
and suspended solids load reductions of 97.4 and 96.9 percent,
respectively, with biological treatment and the addition of deep bed
filtration. Under representative waste use and waste flows in the
industry these load reductions would represent final effluent levels
of approximately 20 to 30 mg/1 BOD and 10 to 20 mg/1 TSS. Under
present experience and application as described in Section VI,
Evaluation of Filter Technology, deep bed filtration may be
reasonably expected ro provide at least an additional 50 to 75
percent removal of BOD and suspended solids beyond effective
biological treatment.
The 13 aerated lagoon systems within the fruits and vegetables pro-
cessing industry handle raw wastes with BOD levels ranging from 388
to 5642 mg/1 and averaging 2126 mg/1. These treatment systems
demonstrated long-term BOD reductions of 90 to 99.8 percent, an
average of 97.9 percent.
Variability of the treated effluents from the treatment systems
described above was analyzed. The ratio of maximum daily BOD and
maximum monthly (30 consecutive days) BOD values was determined to
be 2.0. The same ratios for suspended solids were calculated to be
1.8 for aerated lagoons and 2.6 for the activated sludge and
trickling filter systems.
Analysis of the data gathered for the Miscellaneous Foods and
Beverages and the Fruits and Vegetables Industries indicated that no
statistical correlation existed between influent BOD and TSS levels.
In other words, influent suspended solids values varied erratically
in relation to BOD. Despite this variation, effective high-level
waste treatment was clearly demonstrated to be available and
practicable. Statistical analysis of fruits and vegetables
treatment data also indicated that no relationship exists between
influent and effluent TSS levels.
A concern raised frequently by the corn wet milling industry is the
apparent sensitivity of the activated sludge system to fluctuations
in the influent waste characteristics. As shown above, irany
existing activated sludge systems receiving variable, high strength
organic wastes have been able to consistently produce a highly
stable effluent with low BOD and suspended solids.
A. w. Busch (7) discusses operational problems at some length and
summarizes as follows: "In short, most operational problems with
fluidized systems [activated sludge] are built into design (lack of
ability to control growth rate for example) or are due to faulty
operating concepts," Referring to shock loads, he further states
that "determination of such flow patterns and their anticipation in
process and system design is a vital part of the engineer's
responsibility."
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The information presented above fully substantiates the ability of
biological treatment systems to reliably produce very high pollutant
reductions on a sustained basis with high strength food processing
wastes. With reasonably prudent design and operation, a biological
treatment system can effect overall BOD and suspended solids reduc-
tions in excess of 95 percent and can produce effluent levels of 30
mg/1 and less, despite highly variable raw waste characteristics.
C. CORN WET MILLING INDUSTRY
When waste treatment has been reguired, the corn wet milling indus-
try has for the most part used the complete mix activated sludge
process. There are four mills that treat process wastes and event-
ually discharge treated effluent directly to waterways (one of the
four recycles its effluent into the mill for reuse) . All four of
these mills employ complete mix activated sludge. Five mills pro-
vide pretreatment of process wastes prior to discharge to municipal
systems, and a sixth mill is currently constructing pretreatment
facilities. Three of these six pretreatment plants employ the
activated sludge process; the remainder use other biological
processes. A review of the performance of these treatment facili-
ties is presented below in order to provide a better understanding
of treatment practices within the corn wet milling industry.
1- CPC - Pekj.nf Illinois
CPC"s Pekin, Illinois corn wet mill is an older, medium-sized plant
located on the Illinois River. The mill uses a large volume of
water, 20.5 mgd (77,593 cu m/day), for process and cooling purposes.
Much of this water is used in once-through barometric condensers.
Prior to the late 1960's, all of the wastes from the Pekin mill were
discharged directly to the river without treatment. In 1968, CPC
applied for and received a Research and Development grant from EPA1s
predecessor, the Federal Water Pollution Control Administration.
The grant provided funds for development, design, and construction
of waste treatment facilities. The treatment plant was designed to
handle only concentrated process wastes (less than 1 mgd) and not
the contaminated barometric discharge. Operation of the treatment
facilities began in late 1970. Included in the scheme were
equalization, cooling, nutrient addition, complete mix activated
sludge (aeration and clarification with sludge recycle), dissolved
air flotation, and reaeration. As the Final Grant Report (23)
documents, numerous mechanical and other problems plagued the
plant's first year of operation, and treatment performance has never
reached the original design criteria on a long-term basis.
The following discussion concerns the performance of the waste
treatment facility at Pekin. The industry has claimed that the
Pekin treatment plant does not perform satisfactorily; that it is
subject to shock loads and variations in raw waste and, therefore,
is not capable of producing a stable effluent. Carryover of sus-
pended solids in the effluent is a particular problem. This
investigation confirmed the variability of treatment plant per-
formance at Pekin, but it also established the reasons for this
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variability: Deficiencies in design and operation of the treatment
system and deficiencies with in-plant waste controls within the
manufacturing plant.
Initially the Pekin waste treatment plant was operated at a very
high organic loading rate, specifically a food-to-microorganism
(F:M) ratio of about 0.8. Experience has shown that treatment of
corn wet milling wastes is effectively attained at much lower
loading rates. For example, the new treatment facilities at Clinton
and Muscatine, Iowa are designed for an F:M of 0.3 to 0.35. Pekin
has since made in-plant changes to reduce waste loadings, but the
treatment plant is still subject to influent shock loads that exceed
normal design loading rates. Other design deficiencies include an
undersized clarifier. The Pekin clarifier was designed at an
overflow rate of 600 gallons per day per square foot (24.4 cu m per
day per sq m). Although this value conforms with standard sewage
treatment practice, it is considerably higher than loadings used at
other treatment plants handling high strength organic wastes.
Overflow rates of 400 gpd/sq ft (16.3 cu m/day/sq m) are more common
in the miscellaneous foods and beverages industry (8) The Pekin
Final Grant Report (23) stated that M[a] lower [clarifier] overflow
rate should result in a lower sludge blanket, and less frequent floe
carryover.n The report also made note of severe raw waste shock
loads - shock loads that could be controlled within the plant. The
conclusion was that "further improvement in effluent quality will
require stabilization of the waste load, and improved suspended
solids removal.11
CPC is well aware that the Pekin waste treatment facility needs
improvement. An EPA evaluation of the plant in 1972 concluded:
"With enlarged plant facilities it appears possible to reduce BOD
and suspended solids concentrations below 25 mg/1. Performance of
the existing waste treatment plant cannot be improved significantly
by operational control modifications alone (24).H CPC has performed
its own evaluations (25). studies conducted from November 1972 to
February 1973 concluded that additional equalization (to absorb the
extremely high waste load fluctuations) and additional activated
sludge facilities were required to improve the plant effluent.
CPC's consultant performed studies in 1973 on effluent polishing
techniques, including filtration and dissolved air flotation. The
consultant concluded that new dissolved air flotation facilities
were needed (26). The consultant's conclusions on filtration are
discussed in section VT of this report. Based on the findings of
CPC and its consultant, extensive improvements to the treatment
plant are now being implemented. These improvements include
additional equalization basins, new aeration tanks, new clarifiers,
and a new dissolved air flotation unit (27). Work is scheduled to
be completed by late 1975.
Despite its limitations (and the present in-plant control inade-
quacies within the corn wet mill), the Pekin treatment plant has
demonstrated its ability to perform well for extended periods of
time. For example, between July 1972 and January 1973, BOD reduc-
tion was below 90 percent only 10 percent of the time, and the
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effluent design level of 40 mg/1 BOD was met nearly 60 percent of
the time (23). More recent data substantiate that the treatment
facility can produce a stable effluent. From July 24, 1973 to
August 21r 1973, BOD concentrations exceeded 100 mg/1 only once and
generally were below 50 mg/1. From October 8, 1973, to December 3,
1973, the same conditions were met. Particularly good performance
was recorded in May and June of 1974. Average effluent BOD was 35
mg/1 in May and 32 mg/1 in June. Average TSS was 65 mg/1 in May and
66 mg/1 in June (27). Improved waste treatment and additional in-
plant controls, which would be much easier to implement in a new
manufacturing plant, would enable Pekin to produce a stable treated
effluent on a reliable and sustained basis.
It should again be noted that the waste treatment plant at Pekin
only receives the high strength waste waters constituting less than
10 percent of the total mill effluent. The major portion of the
mill effluent consists of the contaminated barometric condenser
cooling water discharge (once-through cooling water) , which repre-
sents a dilute, but significant waste stream. Total waste loads to
the receiving stream are about 600 Ib/day (272.4 kg/day) from the
treatment plant and 6000 Ib/day (2724 kg/day) from the barometric
cooling waters.
2. CPC - Corpus Christie Texas
CPCfs Corpus Christi plant is a small mill of more modern design
than the mill at, Pekin, Illinois. in 1970, the plant began
installing waste treatment facilities to treat process wastes prior
to discharge to the adjacent ship channel. The Corpus Christi plant
suffers the same failing as Pekin; namely, direct discharge of con-
taminated barometric condenser water without treatment. The problem
is not as severe as at Pekin, however, since the plant does employ a
number of surface condensers. Barometric discharge accounts for 3.4
mgd (12,869 cu m/day) and 264 Ib/day (119.8 kg/day) or 16 Ib/MSBu
(0.286 kg/kkg) of BOD on an average basis (28).
The corpus Christi treatment facility is a piecemeal design. Begin-
ning as an unsuccessful batch treatment operation, it was converted
to an activated sludge system over a period of four years. The sys-
tem originally consisted of three vertical steel tanks, each with
sparged air and a submerged turbine mixer, followed by dissolved air
flotation. Other components were gradually added, including
nutrient addition facilities, an equalization and cooling basin, a
primary tilted plate separator for starch wastes, a fourth aeration
tank (of larger capacity than the first three), and a final
clarifier. The flotation unit was not effective and is now used as
a second clarifier. There is no skimmer on the clarifier, and
solids tend to float to the top and pass over the weir. The
aeration tanks are operated at a very high MLSS (mixed liquor
suspended solids) level, between 6000 and 8000 mg/1 (29, 30) .
The limitations of the Corpus Christi treatment facility result in
an effluent atypical of a well designed and operated activated
sludge system. During the period December 1974 to April 1975, the
21
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effluent averaged 311 mg/1 BOD and 730 mg/1 suspended solids.
Despite this poor performance and the discharge of untreated
barometric condenser wastes, the total BOD discharge from the mill
(including cooling water) was 57.4 Ib/MSBu (1.025 kg/JOtg) as a mean
daily average and 64.6 Ib/MSBu (1.154 kg/kkg) as a mean 30-day
average. These levels are not much above the 1977 effluent
guideline of 50 Ib/MSBu (0.893 kg/kkg) for a maximum month. BOD
discharged from the waste treatment plant was 41.8 Ib/MSBu (0.747
kg/kkg) as a mean daily average and 48.3 Ib/MSBu (0.863 kg/kkg) as a
mean 30-day average (23) .
As at Pekin, a stable effluent (in terms of BOD) is obtained at
Corpus christi during certain periods. For example, from February 9
to 21, 1975, effluent BOD ranged from 9 to 90 mg/1 and averaged 43
mg/1. From March 14 to 29, 1975, effluent BOD values ranged between
10 and 64 mg/1 and averaged 35 mg/1 (27) .
Because of alleged violation of state water quality standards and
failure of the waste treatment facility to achieve acceptable efflu-
ent quality, CPC had extensive evaluations performed during 1974 and
early 1975 (29) . Concurrently, CPC intensified its effort to reduce
waste loads within the elaijt. Additional facilities were installed
to improve operation and divert, remove, or pick up wastes in-plant
and to reduce the potential for accidental discharges. CPC's con-
sultant recommended extensive modifications to the waste treatment
plant, and work has begun to implement the new measures. The
modifications include additional seeded equalization and a final
stabilization lagoon.
ican Maize - Hammond, Indiana
The American Maize corn wet mill is an older plant located on Lake
Michigan. The plant discharges once-through cooling waters and
treated process wastes to the lake. A major pollution abatement
program was undertaken during the late 1960"s. Surface condensers
replaced most of the barometric condensers. Only two small baro-
metric condensers remain in the syrup refinery, one of which is not
presently being used.
American Maize's waste treatment system is a series of three lagoons
that was converted to essentially an activated sludge system u'ith
polishing ponds. Aerators were installed in the first lagoon and a
clarifier with sludge return was added in 1968, process and sanitary
wastes were segregated in 1969, and aerators were installed in the
two polishing lagoons receiving activated sludge effluent in 1970.
The 1977 effluent guidelines would allow American Maize to discharge
a maximum of 3250 Ib/day (1475.5 kg/day) of BOD and suspended solids
for any 30 consecutive days and 9750 Ib/day (4426.5 kg/day) for any
one day. A look at American Maize NPDES reports (31) shows that the
plant is currently meeting these levels. Discharge levels for
January through March 1975 are shown below:
22
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Average for Month
BOD TSS
Maximum for Month
BOD TSS*
Ib/day kg/day Ib/day kg/day Ib/day kg/day Ib/day kg/day
Jan
Feb
Mar
1977 Effluent
Guidelines 3250
NPDES Permit
Levels 2000
1722
1418
421
782
644
191
1995
2002
2080
906
909
944
3819
2193
1313
1734
996
596
5600
6756
5286
2542
3067
2400
1476 3250 1476 9750 4427 9750 4427
908
Calculated by assuming that maximum
concentration occurred on same day.
10,000 4540
flow and maximsn TSS
The current discharge levels for American tfeize are well under both
the NPDES permit levels for the plant and the 1977 effluent
guideline levels.
The total discharge levels from American Maize do not necessarily
indicate that all components of the waste treatment system are
operating well. For example, during the period April 1974 through
March 1975, monthly average values of TSS in the clarifier overflow
ranged from 66 mg/1 to 1292 mg/1. Averages for TSS during the first
three months of 1975 were 628, 651, and 277 mg/1, respectively (32).
The major portions of the American Maize treataent system were
originally designed for an entirely different process and, hence, do
not reflect current design standards for activated sludge systems.
The polishing lagoons, however, provide additional treatment
capacity. Thus, although the total system does not include a well-
designed activated sludge process, American Maize is easily meeting
1977 effluent guidelines with current technology, despite frequent
upsets in their adapted activated sludge system.
^' Clinton Corn Processing Company - Clinton, Iowa
Clinton Corn has recently installed new waste treatment facilities
that include deep bed filtration, part of the 1983 reccmnended
control technology. Accordingly the Clinton treatment system is
discussed separately in Section VII.
5. Pretreatment Facilities
There are five corn wet mills that presently provide pretreatment of
wastes prior to discharge to municipal collection and treatment
systems. These plants include Anheuser-Busch - Lafayette, Indiana;
Cargill - Cedar Rapids, Iowa; Penick & Ford - Cedar Rapids; and A.
E. Staley - Decatur, Illinois and Morrisville, Pennsylvania. A
sixth mill. Corn Sweeteners - Cedar Rapids, is constructing pre-
treatment facilities. The two Staley plants and Corn Sweeteners1
plant employ the corplete mix activated sludge process, and
23
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Anheuser-Busch operates an aerated lagoon system. Penick & Ford's
system is a unique fungal digestion process, with a final clarifi-
cation step soon to be added. Cargill's pretreatment is rather
limited, consisting of settling tanks and some aeration.
All five of the existing pretreatment facilities are operating suc-
cessfully from the standpoint that requirements of the municipali-
ties involved are being met. For example, Anheuser-Busch1s aerated
lagoon system consistently removes 50 percent and more of the BOD in
the raw waste (33) .
D. SUMMARY
Biological treatment processes, particularly activated sludge, are
proven and effective means for handling domestic and industrial
wastewaters. The activated sludge process has been demonstrated in
thousands of applications as a versatile pollution abatement
technology and is well-suited for treatment of high strength organic
wastes.
Many experts in the field of environmental and sanitary engineering
attest to the applicability of activated sludge. Furthermore, an
extensive evaluation of biological treatment systems in industries
generating wastes similar to corn wet milling proves that these
systems can effectively treat variable high strength wastes and can
produce stable, high quality effluents. With good design and
operation, such a treatment system will consistently produce an
effluent containing 30 mg/1 BOD and TSS, despite raw waste varia-
tions. This has been demonstrated with a wide variety of industrial
wastes, including those generated by breweries, edible oil refiner-
ies, malting plants, distilleries, bakeries, wineries, and fruit and
vegetable processing plants.
The activated sludge process has been applied by a number of corn
wet mills in the treatment of their wastes. No plant has imple-
mented a properly designed and operated treatment facility coupled
with good in-plant control. Thus there is presently no example of
best practicable control technology within the industry. Factors
such as limitations in design and operation of the treatment facili-
ties, lack of in-plant controls, and discharge of untreated wastes
have prevented treatment plants from attaining optimal performance
on a long-range basis, A treatment facility at a new corn wet mill
that incorporates good in-plant controls in its design will not be
subject to upset conditions and thus will achieve long-term perform-
ance comparable to the high levels achieved by other industries.
On the basis of experience of treating similar waste from other
industries it is generally concluded with reliance that with the
most careful design, operation, and in-process control, the New
Source Performance standards can be achieved through demonstrated
performance of biological treatment systems. Deep bed filtration
provides an additional assurity as to the achievement of the
required high quality affluent on a reliable and sustained basis.
24
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SECTION V
IN-PLANT CONTROLS
As the Development Document for the Grain Processing Industry (9)
indicated, there are many water recycling and reuse techniques
presently employed in corn wet mills. These techniques have
resulted from efforts to improve product recovery and simultaneously
to reduce raw waste loads. In-plant controls are continuously being
developed and improved.
The Development Document also pointed out that not all existing corn
wet mills employ every available in-plant control to conserve water
and reduce waste loads. Age of the plant and physical constraints
such as space within the plant and land availability are often
determining factors. This is not the case with new plants. A new
corn wet mill will be able to incorporate, in design, many in-plant
controls that are less readily retrofitted into existing plants.
These controls would include segregation of process and sanitary
wastes, recirculating or noncontact cooling systems, spill
containment facilities or overflow tanks, holding tanks to collect
discharges of concentrated wastes or acids, clean-in-place (CIP)
cleaning systems, and instrumentation to monitor and control process
variables and resultant waste streams.
After consultation with the industry (34) and with process equipment
suppliers, it has been determined that a new plant designed or
constructed today would incorporate the majority of available in-
plant controls as a matter of good practice with or without the
demands of pollution control regulations. In fact, with some pro-
cess equipment such as evaporators, there would be little choice.
Process equipment with the most modern water conservation and
pollution control features would also be the most attractive from an
economic or product yield point of view.
The only exception that might be taken regards cooling systems. A
new plant built today that did not face stringent effluent limita-
tions might employ a once-through cooling water system using baro-
metric condensers. The mill would thus discharge a high volume, low
concentration, contaminated waste stream. Faced with effluent
limitations, the new plant designer has two choices. One is to
install barometric condensers utilizing a recirculating water sys-
tem. A cooling tower would be needed, and the blowdown from the
tower would require treatment along with process wastes. The second
choice is to install surface {noncontact) condensers, with or
without recirculation, that would prevent contamination of the
cooling water stream. Surface condensers are more costly to buy and
operate than barometric condensers.
The lack of adequate in-plant controls, coupled with treatment plant
deficiencies at existing corn wet mills, contribute to the inability
to identify a truly exemplary treatment system meeting potentially
achievable performance in the industry. These same deficiencies in
25
-------
current practice also make it very difficult to extrapolate current
treatment performance to new sources. .One cannot conclude that
existing treatment systems are performing as well as possible. It
would be more valid to look at periods of good performance at
existing treatment plants reflecting the absence of upset
conditions, since a waste treatment plant serving a new mill would
experience less raw waste variability and shock loads. Better in-
plant controls will reduce raw waste fluctuations.
In summary, a high degree of in-plant control can be reasonably
expected at any new corn wet mill. Such control will be an integral
part of the basic process design and, if supplemented with flow
equalization, will largely eliminate major raw waste fluctuations.
Elimination of raw waste fluctuations will allow the subsequent
waste treatment processes to produce a stable, high-quality efflu-
ent. In considering the cost of the in-plant controls for new
sources, only the cost of a recirculating or noncontact cooling
water system is directly attributable to pollution abatement.
26
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TABLE 9-1 (CONTINUED)
RESULTS OF STUDIES OH
FILTRATION Of EFFLUENTS FROM SECONDARY BIOLOGICAL TREATMENT
i j A K A C T C R I S T f C .
'"u i"-. ' i;. :L* ^UJ«LE ML:DIA size DLPTM
type mm in
' : " '''- ' -':- ' " ' ' - = ^ -'- . A, t : vatcd i.-.nd 1-2 60 i,
''; r lo« \ _S jJ ,;e
,-' '! J - - >' , i :,. -\c t i a t ed Sand 0.5-2.5 - 1
.;..,.-, : i-'--j;= - L j .. ,'-,.-! f 1 o^' S i ud^e
..-!». -l^l.MlJ
' M , . :K..--, . M . ;. . i . .;: ..vi t v TncU i r.g Sand 1,1 - 1
D J v, n f i o w F i 1 c e r
OJ 'J'-iri .,o Hui-Na . :;r,iyi t v Trickling Sand 1,5-3 - 1
*~" ' " :-- ;; , '- '' sJ " -' '' '- ;.'c wn f 1 o w Filter
i'-., !.:.«;]. uid Si^ucc:' Tricklir.^ Sand 1-2 - . 4
?. a j i a 1 Flow Filter
: -« -.t- 3 Ue , tnsl anJ Ir,.^sJium Activated Sand 1-3 63 5
Pressure Sludge 3
U p f 1 o w 5
5
': -.r.i-i L Je , fcn^Kmd Per^iutit Activated Sand 0.60-1.20 57 3
!lpf low Sludge 3
5
5
. .> :> <.- s i ,1 c , C n g 1 a /i d 3 i m a t e r Activated Sand 0.5-1 3
Ri dial Flow SI uJ^e 3
5
5
' , : ; .i i] \i ri j ._ r [./ n ^ , I nn; e d i urn Tr i c V. 1 i n ^ Sand 1-2 60 4
1 U « A u L : L
g p n f r :
.3
.3-;. 4
-3
. 6-3. 2
-6
. 3
. 3
. 0
. o
. 3
. 3
.0
.0
. 3
. 3
.0
. 0
.5-5.0
IN1
..'!
1 ?
i 2
20
21
22
9
46
a
37
9 '
32
1 1
22
1 1
51
i ^
24
30
. ,-~^-
OL'T
.,»/!
-
C
5
5
9
2
B
6 .
10
1
7
4
5
3
7
4
10
8
kEMOVAL LENGTH
percent h f
60
Sg
75
75
60
74
84
20
74
86
73
60
ft3 '
74
86
62'
08
30
REFERENCE
( 2 - )
(22)
(22)
(22)
(22)
(23)
(23)
(23)
(24)
i, f lo^V
ilter
-------
treatment to meet increasingly stringent effluent requirements.
Filtration applications in wastewater treatment include:
1. removal of biological floe from secondary effluent,
2, removal of precipitates in the process of phosphorus removal,
and,
3. removal of solids remaining after chemical treatment (36) .
Filtration as a tertiary treatment method following secondary pro-
cesses has long been practiced in Great Britain. While the British
practice tends toward the upflow pressure mode, their experience
includes gravity downflow, bi-flow, and radial-flow methods, many of
which are patented processes. In the United states the tendency is
toward the conventional down flow gravity method, although some
pressure filters are presently in use (35, 40) .
EPA Process Design Manual for suspended solids Removal (35)
devotes considerable attention to granular media filtration. The
manual states that 'this process [ filtration J, long applied in
treatment of municipal and industrial water supplies, is becoming
widely used for wastewater treatment both in upgrading existing
conventional plants and in designs of new advanced treatment
facilities." Data on numerous filter installations treating
biological or secondary effluents are given in the manual in Table
9-1, which is reproduced in this report on the following three
pages. Note that in all of these examples, filter effluent
suspended solids never exceeded 10 mg/1, despite influent levels
which varied as high as 50 mg/1. Removals were above 60 percent and
often were 80 percent and higher. In developing x:he New source
Performance Standard for the corn wet milling industry, deliverance
ot a biologically treated effluent to the deep bed filtration stage
at a concentration lex'el of 75 mg/1 BOD and TSS is assumed,
eventhough experience with biological treatment for similar wastes
for other food processing industries indicate achievement of a BOD
and 5E*SS effluent level of 30 mg/1 is generally achievable by
biological treatment. An additional 50 to 75 percent removal of BOD
and TSS is attributable to deep bed filtration beyond biological
treatment,
Many tests have been conducted on both pilot plant and plant scale
levels to determine the effectiveness of the filtration process for
suspended solids and BOD removal, to further refine the process, and
to develop design criteria. Gravity downflow filtration has been
found to be a cost-effective means of reducing suspended solids in
the effluent from wastewater treatment facilities. Both conven-
tional and special design filter beds have been tested. Filtration
of wastewaters has been successfully demonstrated without chemical
addition. In some instances, chemical addition has improved -the
filterability of biologically treated wastewaters and thus has
increased BOD and suspended solids removals.
Hsiung and Cleasby (41) performed studies to develop a simple and
rational method for design and operation of water treatment filters.
Optimum cost for filtration was obtained by developing performance
32
-------
curves with the flow rate determined by consideration of either fil-
trate quality or head loss. They concluded that the results of this
study may be applicable to sewage solids and that such applicability
should be investigated.
Lynam et al (42), in studies conducted at Chicago Metropolitan Sani-
tary District's Hanover plant, found rapid sand filtration of acti-
vated sludge effluent to be a cost-effective process that
consistently produced effluent suspended solids of less than 5 mg/1.
Removals of 76.5 percent were obtained. The study reports that
chemical addition (alum followed by polymer) provided insufficient
improvement of filtrate quality over plain filtration to warrant its
inclusion in future designs.
Tchobanoglous (43) evaluated the performance of various filter con-
figurations including conventional and special bed designs and the
effects of chemical addition. His conclusions were: 1) filtration
efficiency without chemical addition is a function of filter bed
grain size, 2) in most dual-media filters as presently designed the
sand underbed contributes little to overall suspended solids
removal, and 3) polyelectrolytes can be used to aid in removal of
suspended solids. At a filtration rate of 5,15 gpm/sq ft (3.5
liters/sec/sq m) and with polyelectrolyte addition, an average
influent suspended solids concentration of 23.5 mg/1 was reduced to
1 to 3 mg/1. Filter operating periods (run lengths) were between 4
and 5 hours. Suspended solids removals ranged from 87 to 96
percent.
Tchobanoglous and Eliassen (44) investigated filtration of activated
sludge effluent in a pilot plant study. They developed a
generalized rate equation based on size of filter medium, rate of
filtration, influent characteristics, and the amount of material
removed within the filter. Using 0.488 mm diameter sand, suspended
solids were reduced from 6.3 mg/1 to 2 mg/1, a 68 percent removal.
Filtration rate was 5.8 gpm/sq ft (3.9 liters/sec/sq m) and run
length was 6.25 hours. The top 1-inch (2.54 cm) of the filter
removed 75 percent of the suspended solids, and no solids were
retained below a depth of 6 inches (15.2 cm).
Baumann and Huang (45) conducted a pilot plant study using effluent
from the Ames, Iowa standard rate trickling filter, objectives were
to determine the feasibility of using granular filtration as an
effluent polishing step and to develop a method and pilot plant test
procedure to be used in the design of filters for tertiary
wastewater treatment. They concluded that use of a dual-media
filter (anthracite over sand) increases filter capacity and provides
for better utilization of the filter depth and that it is desirable
to have the anthracite as coarse as possible and the sand as fine as
possible. Best results were obtained by a bed of coarse anthracite
overlying fine sand, which produced a better quality effluent
without significant head loss development as compared with a coarser
sand topped by the same size anthracite.
33
-------
Culp and Hansen (46) found that up to 98 percent of the suspended
solids found in an extended aeration treatment plant effluent with
21-hour aeration of domestic sewage conoid be removed by filtration.
Turbidities as low as 0.3 jtu were obtained without the use of
coagulants.
Culp and Culp (47) report that filterability of sewage solids is
affected by the degree of flocculation attained in the secondary
process and that activated sludge achieves the best flocculation
results as compared to trickling filter and physical-chemical
processes. Flocculation is proportional to aeration time and
inversely proportional to FrM ratio. Aeration basin MLSS variations
in the normal operating ranges of 1,500 to 5,000 sag/1 do not affect
filterability. With domestic wastes, suspended solids removals from
70 to 98 percent can be obtained at aeration times of 6 to 10 hours,
respectively. Biological processes, in general, produce a more
fully developed floe than chemical coagulation, and the higher
removal percentages were obtained with the effluent from an extended
deration plant. Culp and Culp present the following levels as
guides to the suspended solids concentrations that might be achieved
when filtering a typical secondary effluent without addition of
chewical coagulants:
process Effluent TSS
High-rate tricltling filter 10-20 mg/1
Two-stage trickling filter 6-15 mg/1
Contact stabilization 6-15 mg/1
Conventional activated sludge 3-10 mg/1
Activated sludge with load factor
(FrM) less than 0.15 1-5 mg/1
Culp and Culp indicate that, although mixed-media filters can
tolerate higher suspended solids loadings than other filtration
processes, there still is an upper limit at which economically long
runs can be maintained. The authors state that:
With activated sludge effluent suspended solids loadings of up to
120 mg/1, filter runs of 15-24 hr at 5 gpm/sq ft [3.4 liters/sec/sq
m] have been maintained when operating to a terminal head loss of 15
ft [4.6 «} c>f water. Suspended solids concentrations of 300 rag/1 or
more will lead to uneconomically short filter runs, even when using
a mixed-media filter...Should the secondary plant involved have a
history of frequent, severe upsets resulting in secondary effluent
suspended solids concentrations of 200-500 mg/1, an intermediate
settling tank between the secondary clarifier and the filter with
provision for chemical coagulation during upset periods should be
made (47).
34
-------
One advanced wastewater treatment plant that includes dual-media
filtration has been in operation since 1968 (48). The effluent is
of such high quality that turbidity is monitored rather than sus-
pended solids. The effluent from this plant is used to recharge the
water table in Nassau County, New York. The process as reported by
Vecchioli et al provides for the removal of suspended solids,
phosphates, dissolved organics, and MBAS (i.e., detergents or
surfactants). Treatment after activated sludge includes clarifi-
cation (where alum is added), dual-media filtration, and activated
carbon adsorption. Suspended solids removals of 99 percent are
obtained.
Most filtration rates reported in the literature vary from a low of
1 to a high of about 10 gpm/sq ft (0.7 to 6.8 liters/sec/sq m). In
optimization studies, the rate has been established at about 6 or 7
gpm/sq ft (U.I to 4.7 liters/sec/sq m). Studies of ultra-high rate
filtration of activated sludge effluent in Cleveland (49) concluded
that no significant relationship existed between filtration rates
and effluent BOD, COD, and TSS concentrations in the range of rates
(8 to 32 gpm/sq ft or 5.4 to 21.7 liters/sec/sq m) used in the
studies. The investigation also revealed that for influent
concentrations of less than 30 mg/lr the filter effluent generally
remained in the range of 1 to 12 mg/1 with or without polymer or
coagulant and polymer addition, but for influent concentrations
above 60 mg/1, filtration with coagulant and polymer addition pro-
duced a higher quality effluent.
During the ultra-high rate filtration study in Cleveland (49), an
upset condition caused by the breakdown in the sludge incineration
process forced the recycling of digested sludge through the plant.
The filter effluent rapidly deteriorated from 2 to 10.2 mg/1 sus-
pended solids. To correct the problem, chemical addition of alum
and polymer restored the effluent quality to an acceptable 5.1 mg/1.
Filter efficiencies were 88, 54, and 93 percent before the upset,
during the upset, and after chemical addition, respectively.
In evaluating granular media filtration as a method for upgrading
waste treatment facilities, Middlebrooks et al (50) state: "The
simple design and operation of this process makes it applicable to
wastewater streams containing up to 200 mg/1 suspended solids.
Filtration rates can range from 25 to 50 gpm per sq ft [17.0 to 39.9
liters/sec/sq m] for coarse solids to 2 to 5 gpm per sq ft [1.4 to
3.4 liters/sec/sq m] for colloidal suspensions. The versatility of
filter bed designs (media sizes and depths) is such that nearly any
effluent quality can be achieved."
Tertiary filtration has been applied successfully to many types of
industrial wastes. Industries that are either employing filtration
or have successfully tested and are installing filters include:
steel manufacturing, petroleum refining, brewing, corn wet milling,
wine processing, and food processing (51, 52, 53, 54, 55, 56).
/
Multi-media filtration has had particular application in the petro-
leum refining industry, where at least three refineries are known to
35
-------
successfully treat refinery wastewaters after biological treatment.
These applications represent some of the longest-term use of modern
filtration facilities employed with biological treatment systems for
treatment of strong industrial waste (BOD up to 800 mg/1 and TSS up
to 300 mg/1) (57) .
Ample supportive data is available on the long-term performance of
these systems. These plants in which multi-media filtration has
been applied include Amoco Oil Company, Yorktown, Virginia; Marathon
Oil Company, Robinson, Illinois; and Southwestern Oil and Refinery,
corpus Christi, Texas. At the Amoco Oil Company, Yorktown, Virginia
plant, the filtration system follows an aerated lagoon biological
system. The plant served as an EPA demonstration project. Quar-
terly reports submitted to EPA establish the underdesign of the
aerated lagoon and substantiate poor performance of the biological
system. Upsets in performance of the biological system in turn gave
rise to operational difficulties with the subsequent filter,
resulting in shorter filter runs and performance reduction. Even
under these limitations, the filter has been effective in reducing
influent TSS of 25 mc;/l to 10 mg/1 in the final effluent on a sus-
tained basis, a pollutant reduction of 60 percent.
The successful application of filtration is also quite well docu-
mented at the Marathon Oil Company, Robinson, Illinois plant. The
filter handles effluent from an activated sludge biological treat-
ment system and is designed for a maximum influent TSS of 40 mg/1.
In recent months (after installation of the filter) effluent from
the biological system has averaged 49 mg/1 TSS, and the filter has
been successful in reducing the waste load to a TSS of 11.2 mg/1
over the last 18-month period - a total TSS reduction through the
filter of approximately 77 percent. It is important to note that
this filter performance resulted with an average overload in rela-
tion to filter design loading of 25 percent. Also, prior to
installation of the filter, average effluent TSS from the biological
system was 19 mg/1 as compared to 49 mg/1 after the filter
installation - seemingly indicating less emphasis on proper opera-
tion and maintenance of the biological system after installation of
the filter and increased reliance on the filter for production of a
high-quality effluent. Similar results were attained at the
Southwestern Oil and Refining Company, Corpus Christif Texas, as
shown by 4 months of data (22).
A fourth refinery, Clark Oil at Hartford, Illinois, has recently
installed treatment facilities that include an activated sludge
system followed by dual-media filters. The plant was started up in
early 1975 and presently meets the Illinois EPA effluent require-
ments of 20 mg/1 BOD and 25 mg/1 TSS, without the dual-media
filters. The filters have yet to be put on-line, but will be
shortly in anticipation of more stringent effluent requirements.
Average BOD levels in the biological effluent were 14.1 mg/1 in
April 1975 and 7.7 mg/1 in May 1975 (58).
36
-------
Another example of successful application of biological treatment
and multi-media filtration to high strength organic wastes can be
found at Welch Foods' Brocton, New York grape processing plant. The
treatment system consists of activated sludge followed by
filtration. The seasonal average BOD concentration in the raw waste
is 4096 mg/1. A summary of the filter performance is presented
below:
Activated Sludge Multi-media Filtration
Effluent Effluent
Season Average 20.6 28.1 8.1 8. a
Maximum 30-Day 34.0 78.1 13.0 9-2
Maximum Day 114.0 216.0 32.0 20.0
The data indicate the following filter performance levels:
Percentage Percentage
TSS Removal
Seasonal Average 61 70
Maximum 30-Day 61 88
Maximum Day 72 91
The data also indicate that BOD and TSS levels in the filtered
effluent were 13.0 mg/1 and 9.2 mg/1, respectively, for the maximum
month (30 consecutive days). Maximum day BOD was 2.5 times the
maximum month value, and maximum day TSS was 2.2 times the maximum
month value. On a seasonal average basis, BOD reduction was 99.5
percent through the activated sludge system and 99.8 percent through
the activated sludge and filter combined (22,59).
The table on the following page was taken from the Development
Document for the Renderer Segment of the Meat Products and Rendering
Processing Point Source Category (60) . It is a summary of
filtration results for a variety of biologically treated effluents.
The Development Document concluded that "the rapid sand filter has
also been receiving more extensive application in municipal sewage
treatment for tertiary treatment; thus, its use in tertiary treat-
ment of secondary treated effluents from any type of meat or
rendering processing plants appears to be a practical method of
reducing BOD and suspended solids to levels below those expected
from conventional secondary treatment."
A positive feature of filtration is the ability to handle reasonable
fluctuations in solids loadings without serious impairment of
effluent quality. These fluctuations can be absorbed by increased
backwash frequency. This point is discussed by E. R. Baumann in
D§§i2G Qt filters for Advanced Wastewater Treatment (61) :
37
-------
Toble 13A.
ration of
Ce
Tvce
Gravi ';;,'
ilter Infl
TOD
1 5-
-i>" r TI.'
W
OQ
Activated Sludge
Extended
Aeration plus
setllipy
Trickling
Filter
Activated. Sludge
with Clarifier
Contact
Stabilizdtion
(raw waste
includes
cannery)
Miscellaneous
Trickling
Filter with
Nitrification
pressure,
f!u! ti -media
Gravity,
Sand
wulti-media
sand
(slow and
rapid)
sana
11-50
7-36
15-130
10-50
30-2180
3-75
18
(AVE)
15-75
3-8
1-4
2-74
2-4
2-6
9-20
1
-20
^-27
2.4
AVE)
'?-R
_I n
*
-------
The process of filtration is one which is unusual in that it will
never, if properly designed, provide a grossly inferior quality of
effluent. In general, if a filter can provide the desired effluent
quality under normal conditions, upsets in pretreatment processes
wil1 provide shorter filter runs and not signif icantly poorer
effluent quality. Thus, if under normal conditions the effluent SS
are running at 18 mg/1 and suddenly increase to a level of 30 or 40
mg/1, the principal effect will be a significant decrease in run
length but a relatively lesser increase in effluent SS.
C. EXPERT OPINION ON APPLICABILITY OF FILTRATION TO CORN WET
MILLING WASTES
CPC International, inc. has submitted a consultants report on the
application of deep bed filtration as an effluent polishing
technique at the Pekin, Illinois corn wet mill. The report (26)
presents the results of pilot studies conducted in 1973. It was
concluded that in-depth filtration was technically not a reliable
method for meeting the required Illinois EPA effluent standards of
25 mg/1 TSS and 20 mg/1 BOD. The Eighth Circuit Court cited this
report in their decision (footnote at 39) .
The filtration report and test data were reviewed by Dr. E. Robert
Baumann of Iowa State University, a recognized expert on filtration
of water and wastewater. The complete text of Dr. Baumann's
analysis, including comments on the ability of the recommended
technology to meet the New Source Performance Standards, is appended
in this report (62).
Dr. Baumann concluded that the filter test results in the consult-
ant's report to CPC do not lead to the conclusion that filtration is
an unacceptable technology for meeting the New Source Performance
Standards. In reviewing the test data, he noted that "it would
appear that with only a few exceptions the filter runs were being
made during periods while the activated sludge process was upset."
In other words, the effluent being tested was not characteristic of
effluent from a well-run treatment system. Dr. Baumann stated that
"it must be concluded that on the basis of the few runs relating to
near normal activated sludge process performance in the Weston
report that dual media and multi media filters both performed
adequately with respect to effluent polishing." Dr. Baumann1s
observations included the following points:
1. "The failure of the coarse dual media filter was obviously due
to improper media selection...The performance of the multi media
filter is not at a level that would be expected with proper design."
2. Anionic polymers apparently were effective, "but their use was
not followed with an experimental design that employed a rational
basis for selection of dosages."
3. contact time for formation of a filterable floe was apparently
not provided.
39
-------
**' nh redesigned multi media filter using the top two media about
like that in the fine dual media filter and a smaller sized garnet
compatible with them should provide excellent operation at rates
even as hic[h as 3 to 4 qpm/sq ft provided that adequate contact time
is provided with the arionic polymers."
Dr. Baumann also concluded that the ability of deep bed filter to
function as a back-up system during a biological treatment upset was
clearly demonstrated by the test data. During the filter runs
involving very high influent suspended solids (415, 900, 1490 mg/1) ,
both the dual-media and multi-media filters produced removals o£ 94
to 99 percent.
Dr. Baumann summarized his findings on the CPC filtration report as
follows:
In general, the Weston report demonstrates the fact that deep bed
filters can consistently provide from 50 to 70 percent removal of
suspended solids from a wastewater that has been given adequate
pretreatment. The report also demonstrates the fact that deep bed
filters will, in general, provide an adequate back-up system for the
trapping of most of the solids that may be carried over from the
activated sludge process when upsets involving bulking sludge
occurs.
Dr. Baumann also evaluated the ability of the recommended treatment
technology to meet the 1983 effluent guidelines. He concluded that
the guidelines can be met provided that:
1. The activated sludge system is designed for a low loading rate
or F:M ratio.
2. Adequate controls, for sludge bulking are provided in design,
i.e., polymer feed capability, hydrogen peroxide addition, deeper
clarifier design.
3. The deep bed filter media is properly sized and matched, the
wastewater is chemically pretreated prior to fi3tration, and
adequate contact time is provided for floe removal.
In assessing the 1983 and New Source effluent levels. Dr. Baumann
stated that «i would expect such a plant [properly designed and
operated activated sludge-granular media filtration with chemical
pretreatment] to be able to meet the BAT effluent standards for a
medium size corn wet mill".
D. SUMMARY
Deep bed filtration is a demonstrated and available technology. It
is universally applied in the treatment of water supplies for
municipalities and industries and can produce effluents containing
essentially no suspended solids in these applications. Filtration
has been successfully employed in the treatment of municipal and
industrial secondary (biologically treated) effluents. The
40
-------
literature and other data clearly document this fact. The process
has been sufficiently demonstrated to enable the development of
meaningful design criteria and has been employed in numerous
applications. In municipal applications, a well-designed filter can
be expected to reduce suspended solids by 80 percent and more and to
produce an effluent containing less than 10 mg/1 TSS. Similar
results can be anticipated with industrial wastes if the preceding
biological treatment system is well designed and operated. It has
also been demonstrated that deep bed filtration performs as an
effective back-up system during periods of biological treatment
upset and thus helps to insure that a stable effluent will be
produced.
Filtration is applicable to corn wet milling wastes. The process
has been demonstrated with other high strength organic wastes.
Expert opinion supports this applicability, as well as the ability
of a well designed treatment system to meet the New Source
Performance Standards. Furthermore, as will be shown in Section
VII, deep bed filtration has been successfully applied in the full
scale treatment of wastewaters at an existing corn wet mill.
41
-------
-------
SECTION VII
CLINTON CORN WASTE TREATMENT
The Clinton Corn Processing Company's corn wet mill is of particular
concern since it has installed much of the end-of-pipe treatment
technology recommended to meet the New Source Performance
Standards ,; namely, activated sludge followed by deep bed
filtration. It is important to evaluate efforts at Clinton in the
proper perspective. Although some general conclusions can be made,
there are many conditions at Clinton that do not apply directly to
projected conditions at new plants. The following discussion
summarizes Clinton* s pollution abatement efforts, evaluates the
current performance of Clinton's new waste treatment facility, and
finally specifically evaluates the performance of Clinton's deep bed
filters.
A. BACKGROUND AND POLLUTION ABATEMENT EFFORTS
The Clinton mill is a large, old plant located on the Mississippi
River in Clinton, Iowa. The manufacturing plant includes corn pro-
cessing facilities and a distilled spirits operation. The plant has
undergone almost continuous improvement and expansion.
Prior to 1973, all wastes from the Clinton plant were discharged
directly to the Mississippi River. A major pollution abatement
program was undertaken to reduce waste loads to the river. Several
barometric condensers within the plant have been replaced with sur-
face condensers, thereby reducing pollutant loads. Clinton plans to
make further condenser replacements and improvements. Sanitary
wastes have been segregated from process wastes and routed to the
municipal sewage treatment plant. Steps have been taken and still
are being taken to reduce raw waste loads and spills within the
plant.
A major portion of the pollution abatement program was the construc-
tion of new waste treatment facilities. Land is limited at the corn
mill site, and the treatment plant had to be located almost a mile
away. The treatment facilities include cooling towers, a biological
packed tower or trickling filter with synthetic media, complete mix
activated sludge (aeration and clarification), chlorination, and
dual-media filtration. screening and limited equalization of the
raw waste are provided at the manufacturing plant. The biological
tower was installed in September 1973, the filters were placed into
service in November 1974, and the full design waste load was being
treated as of April 1, 1975-
The treatment plant was designed to handle 3 mgd (11,355 cu m/day)
of process wastes. The treated effluent is returned to the mill for
cooling uses. Ultimately, spent barometric condenser water is dis-
charged directly to the river from the mill.
43
-------
Clinton is still implementing in-plant controls to reduce waste
loads. Clinton believes that their present program and new waste
treatment facility will allow the plant to meet by January 1976 the
standards of the NPDES permit issued April 17, 1975 (63). The NPDES
permit levels are identical to the 1977 Effluent Guidelines.
B. EVALUATION OF TREATMENT PLANT PERFORMANCE
In evaluating data from the Clinton waste treatment facility, there
are a number of factors that must be considered. At issue here are
New Source Performance Standards and the ability of a new corn wet
mill with proper in-plant controls, cooling water practices, and
waste treatment to meet the New Source Performance Standards.
Although Clinton's treatment facilities include activated sludge and
deep bed filtration, the following points must be strongly
considered:
1. Clinton is an older mill lacking many in-plant control
measures. Clinton still experiences in-plant accidental spills,
such as acid spills (June 2) and sugar spills (June 8), that
materially affect raw waste load variability and treatment plant
performance (63) .
2. Although changes are planned, Clinton continues to use large
volumes of once-through barometric condenser water that contribute
greatly to total waste load discharge to the river.
3. The Clinton waste treatment plant is receiving higher suspended
solids loadings in the raw waste than were anticipated in design.
Presently, only screening of the raw waste prior to equalization is
provided. Additional pretreatment facilities are planned to
alleviate the problem of excessive raw waste suspended solids.
4. Limited raw waste equalization is provided at Clinton. Deten-
tion time provided in the equalization basin is only 5 to 6 hours.
The Development Document for the Grain Mill Industry (9) recommends
12 to 18 hours, and several mills have provided up to 24 hours of
equalization.
5. The Clinton waste treatment facility is new and still
undergoing shake-down operations. Operating parameters such as
amount of sludge recycled, dissolved oxygen levels in aeration, and
amount of recycle through the biological tower (trickling filter)
are still being varied to determine optimum operating conditions.
6. Aeration basin dissolved oxygen levels were found to be insuf-
ficient in the original design. On June 14, 1975 additional
aeration equipment was installed in the basins. Improvement in
plant performance, particularly regarding mixed liquor
settleability, has been observed since that time.
7. The existing data record does not necessarily indicate the
performance of the deep bed filters. A malfunctioning check valve
has permitted flow to bypass the filters at various times. The
44
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limited historical data on treated effluent, therefore, include the
contribution of unfiltered wastewater during undeterminable periods
of time.
8. Total discharge to the river from the Clinton mill includes
water treatment sludge. This results from treatment of river water
prior to in-plant process uses. Clinton has installed a clarifier
and filter system for river water treatment, and the sludge will
eventually be disposed of at a landfill. This will greatly reduce
the suspended solids and a portion of the BOD presently discharged
to the river from the mill,
Despite the limitations discussed above, the Clinton waste treatment
facility is functioning quite well, producing a high-quality
effluent in terms of BOD and turbidity. Clinton has supplied daily
sampling data for their waste treatment facility (64). This data is
the most current and representative information available, particu-
larly after April I, 1975, when the full design waste load was being
treated. The data indicate that during the period November 1974 to
May 1975, average monthly BOD loadings to the treatment facility
ranged from 1264 mg/1 to 1691 mg/1 in terms of concentration and
27,409 Ib/day to 36,668 Ib/day (12,443 to 16,647 kg/day) in terms of
load. Monthly suspended solids levels ranged from 336 mg/1 to 600
mg/1 and 7286 Ib/day to 11,009 Ib/day (3308 to 4998 kg/day).
Treatment plant
summarized below:
effluent levels for November 1974 to May 1975 are
BOD
Clinton Waste Treatment Efffluent
Turbidity TSS*
Month
Nov 1974
Dec 1974
Jan 1975
Feb 1975
Mar 1975
Apr 1975
May 1975
mg/1
54
44
86
39
17
16
26
Ib/day
1091
844
1864
846
369
334
585
Ib/MSBu
10.9
8.4
18.6
8.5
3.7
3.3
5.9
jtu
-
8.3
18.4
20.6
5.2
6.8
4.9
mg/1
133
74
1U7
54
70
101
135
Ib/day
2440
1419
3087
1172
1518
2106
3040
Ib/MSBu
24.4
14.2
30.9
11.7
15.2
21.1
30.4
*Not necessarily filter effluent.
Suspended solids levels in the effluent are higher than anticipated,
but it must be recalled that these levels do not reflect filter per-
formance, since part of the secondary effluent bypasses the filters.
45
-------
If Clinton Corn was to eliminate its direct discharge of contami-
nated cooling water, either by recirculation or installation of
surface condensers, the above treatment data show that the 1983
Effluent Guidelines (20 Ib/MSBu BOD and 10 Ib/MSBu TSS for maximum
month) are well within reach at an existing plant with present-day
technology, even without filtration of the total secondary effluent.
Since the 1983 guidelines are identical to the New Source
Performance Standards, Clinton, an existing facility, would be
meeting standards for new sources.
C. PERFORMANCE OF DEEP BED FILTERS
From an operational point of view, Clinton indicates that their deep
bed filters are performing quite satisfactorily (63), There have
been no problems with clogging, excessive head loss, or excessive
backwashing. Backwasn cycles are normally 12 to 16 hours apart.
Shorter filter runs do occur when clarifier overflow solids increase
and thus solids retained in the filter increase, demonstrating the
ability of the filters to handle variations in solids loading.
Filter operation was monitored at Clinton between November 25, 1974
and February 16, 1975. Reductions in COD, BOD, suspended solids,
and turbidity were determined (64). The data are presented on the
following page. Suspended solids removals ranged from 45 to 100
percent and averaged 77 percent. BOD reductions through the filter
alone ranged from 6 to 53 percent and averaged 29 percent.
Additional limited sampling was performed by EPA's contractor during
June 9-11, 1975. A summary of the data collected is included in the
second table that follows. Results of this sampling indicated
suspended solids removals of 50 to 68 percent attributable to the
filter. BOD removals were 0 to 32 percent. Abnormally high raw
waste suspended solids and an aerator failure in one of the aeration
basins may have been the cause of increased effluent BOD and TSS
values during the sampling period (65).
D. SUMMARY
Data from the Clinton Corn waste treatment facility is of interest
since deep bed filtration is used following complete mix activated
sludge. Despite the fact that the corn wet mill is quite old and
both the mill and the treatment plant suffer from several limita-
tions, the following conclusions can be made:
1. The Clinton Corn wet mill will meet the 1977 Effluent Guide-
lines in 1976.
2. The complete mix activated sludge process, when applied to corn
wet milling wastes, can produce a stable, high quality effluent with
BOD concentrations of less than 30 mg/1.
3. Deep bed filtration is transferable to the corn wet milling
industry and has been demonstrated as an effective treatment process
at an existing corn wet mill.
46
-------
O
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rb
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CT --J
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O rr
-------
SECTION VIII
To determine achievable effluent limitation levels and to develop
associated cost data, three model new corn wet milling plants were
synthesized. Since the present trend within the industry is toward
production of sweeteners, the new mills are logically assumed to
convert the large part of their grind into syrups. To evaluate a
range of plant sizes for cost evaluation and pollution control
impact, three mills of 30,000; 60,000; and 90,000 bushels/day
capacity were developed.
A. DESIGN CRITERIA
Important parameters used to develop the three model plants included
wastewater flow to be treated, BOD loading, and suspended solids
loading. Data received from industry (64, 66, 67) on projected raw
waste flows for new mills ranged from 8333 gal/MSBu to 66,667
gal/MSBu (1.2 to 9.9 cu m/kkg). Data from more recently constructed
and operating corn wet mills in the 30,000 bu/day size range
indicate that a waste flow of 1 mgd (3785 cu m/day) or 33,333
gal/MSBu (5.0 cu m/kkg) may reasonably be anticipated for a plant
employing recirculation of cooling water. Since the latter value
falls within the mid-range of values projected by industry and is
demonstrated at mills presently in operation, it was chosen as the
design value. This value reflects wastewater loadings resulting
from in-plant controls presently practiced at newer mills in the
industry. These plants do not necessarily reflect the incorporation
of all in-plant pollution reduction controls that are known to have
application within the industry.
Industry projections of new sweetener plant raw waste BOD load
ranged from 233 to 500 Ib/MSBu (4.2 to 8.9 kg/kkg). For design
purposes, a load of 400 Ib/MSBu (7.1 kg/kkg) was selected for a new
plant, a value that corresponds to the level selected for the model
plant in the Development Document (9) . The cost of treatment
facilities for a new plant generating only 250 Ib/MSBu (4.5 kg/kkg)
of raw waste BOD (at the lower end of the load range projected by
industry) was also evaluated to determine the significance of the
design value upon treatment facility capital and operating costs.
Projections of suspended solids loads for new corn wet mills sub-
mitted by the industry ranged from essentially zero to 166 Ib/MSBu
(3.0 kg/kkg). Information on existing mills indicates average sus-
pended solids loadings of 200 Ib/MSBu (3.6 kg/kkg), and this value
was chosen as a conservative number.
New plant raw waste criteria used in this evaluation are summarized
below:
51
-------
Capacity _____ Flow __ _ _____ BOD ____ _ _____ TSS
qal/MSBu mgd Ib/MSBu ~lb/day.~ Ib/MSBu Ib/day.
30,000 33,333 1.0 400 12,000 200 6,000
60,000 33,333 2.0 400 24,000 200 12,000
90,000 33,333 3.0 400 36,000 200 18,000
B. WASTE TREATMENT COMPONENTS
As discussed in Section IV, data available from treatment applica-
tions involving high strength organic wastes indicate that a well
designed and operated activated sludge system (or other biological
process) preceded by equalization and coupled with good in-plant
waste controls will produce a stable, high quality effluent. This
has been demonstrated within numerous industries and at least at one
corn wet mill. Furthermore, available data indicate that deep bed
filtration is an effective means of polishing effluent from
biological treatment systems. This is discussed previously in
Sections VI and VII.
Based on the above information, the treatment systems for the model
new corn wet mills are assumed to contain the following components
or unit processes:
1. Grit removal
2. Flow equalization
3. Nutrient addition
4. pH control
5. Complete mix activated sludge
6. Secondary clarification
7. Chlorination of effluent
8. Chemical coagulant addition
9. Deep bed or mixed-media granular filtration
10. Sludge thickening
11. Sludge centrifugation
An aerated grit chamber is provided with a design capacity of 2.5
times the average wastewater flow. The detention time is selected
as 3 minutes, with 5 cubic feet per minute (cfm) of air (0.14 cu
m/min) being provided per linear foot (0.305 m) of grit chamber.
The detention time in the equalization basin is chosen as 18 hours
at average daily flow. Aeration and mixing are also provided. The
52
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activated sludge process design is based on an F:M of 0.3, MLSS
concentration of 2000 mg/1, and aeration requirement of 1500 cfm/lb
(93.6 cu m/min/kg) of BOD applied. The clarifier overflow rate is
chosen at 350 gpd/sq ft (14.2 cu m/day/sq m) with a detention time
of 4 hours. The filters are sized for a loading rate of 4 gpm/sg ft
(2.7 liters/sec/sq m). All of the above design values are based on
widely used and accepted sanitary engineering design criteria.
C. PERFORMANCE OF WASTE TREATMENT FACILITIES
Information gathered on treatment of brewery, distillery, and many
other food processing wastes and information on stable operation
attainable with treatment of corn wet milling wastes provide a sound
basis for predicting corn wet milling waste treatment facility per-
formance. The data indicate that a well designed, operated, and
maintained system treating wastes from a new corn wet mill will
produce an effluent containing 30 to 40 mg/1 of BOD and total sus-
pended solids (TSS) on a long-term average basis. For the model new
corn wet mills outlined above, these levels correspond to 8.3 to
11.1 Ib/MSBu (0.1U8 to 0.198 kg/kkg) of BOD and TSS. Data on
filtration of effluents from biological treatment of municipal and
industrial wastes provide an equally firm basis to conclude that a
properly designed deep bed filter will reduce the above effluent BOD
levels by 50 percent and the effluent TSS levels by 70 to 80
percent. These reductions are predicated on good biological treat-
ment preceding the filter. The filter effluent for the model plant
will contain a BOD load of 4.2 to 5,6 Ib/MSBu (0.075 to 0.100
kg/kkg) and a TSS load of 1.7 to 3.3 Ib/MSBu (0.030 to 0.059 kg/kkg)
on a long-term average basis. A schematic diagram - of the
recommended treatment system and a tabulation of the achievable
effluent levels for a 30,000 bushel/day corn wet mill are presented
on the following page.
The effluent values presented above represent long-term averages and
must now be related to the maximum monthly and maximum daily levels
in the New Source Performance Standards. The corn wet milling
industry has suggested that these relationships may best be
established by the use of calculated variability factors. While
such statistical calculations are not without merit, there are
important limitations in utilizing this approach that must be
recognized for the corn wet milling industry. First, the data base
must reflect good, stable operation, including good in-plant
controls and end-of-pipe treatment, second, the data base must be
applicable to new plants. The data on existing treatment plant
performance in the corn wet milling industry are deficient in both
respects. All existing complete treatment plants suffer from either
severe design and operating deficiencies or inadequate in-plant
controls. Plants operating under such 1es s than des ir able
conditions will invariably experience greater effluent fluctuations
and more frequent biological system upsets. In other words, such
plants will inherently generate a higher variability factor than
well-designed and operated facilities at mills with good in-plant
controls. Moreover, not one of the mills for which meaningful
53
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EFFLUENT PERFORMANCE LEVELS FOR A
NEW 30,000 BUSHEL/DAY CORN WET MILL
Nutrientc/pII control
Haw W.-ustc
1.0 mgd
1440 mg/1 BOD
720 mg/1 TSS
Grit
Chamber
\
Aerated
Equalization
Complete Mix
Activated Sludge
Chloririat ion/Coagulants
To Receiving Water
1.0 mgd
15-20 mg/1 BOD
6-12 mg/1 TSS
Deep" Bed
Filtration
'
1.0 mgd
30-40 mg/1 BOD
30-40 mg/1 TSS
Secondary
Clarification
"
Raw waste characteristics
Flow 1.0 mgd
BOD 1440 mg/1 = 12,000 Ib/day = 400 Ib/MSBu
TSS 720 n.g/1 = 6,000 Ib/day = 200 Ib/MSBu
Waste characteristics after grit removal, equalization,
activated sludge, and clarification
Flow 1.0 mgd
BOD 30-40 mg/1 - 250-334 Ib/day = 8.3-11.1 IVMSBu
TSS 30-40 mg/1 = 250-334 Ib/day = 8.3-11.1 Ib/MSBu
Waste characteristics after deep bed filtration
Flow 1.0 mgd
BOD 15-20 ir-g/1 - 125-167 Ib/day - 4.2-5.6 Ib/MSBu
TSS 6-12 mg/1 - 50-100 Ib/day - 1.7-3.3 Ib/MSBu
54
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SECTION IX
NON-WATER QUALITY ASPECTS
Factors such as air pollution control and solid waste disposal are
discussed in the Grain Processing Development Document (9). This
discussion of nonwater quality aspects remains valid based on this
additional study.
One industry representative has provided data (67) on projected
power requirements for new corn wet mills. These projected demands
in terms of kilowatt-hours (kwh) are presented below:
Capacity
(bu/day)
30,000
60fOOO
90,000
Power Requirement
(kwh/bushel) ~
4.5
4.0
3.8
Power
(kwh/day)
135,000
240,000
342,000
The same industry representative estimates that waste treatment
power requirements to meet New Source Performance Standards will be
10 or 15 percent of total mill power requirements. This estimate
appears to be high based on analysis of data provided by the corn
wet milling industry in 1973 and projections of power requirements
for new treatment facilities. These data indicate that a maximum
increase of only 3 to 5 percent would be reasonably expected for
treatment facilities at a new corn wet mill.
-------
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SECTION X
SUMMARY
INTRODUCTION
Public Law 92-500 requires the Agency to publish performance
standards for new sources under authority of Sections 306 (a) and
307 (c).
Effluent Limitations for Existing Sources, New source Performance
Standards and Pretreatment Standards for New Sources for the Grain
Mills Point Source Category were proposed on December 4, 1973 (38 FR
33438) and promulgated on March 20, 1974 (39 FR 10512).
On May 5, 1975, the U.S. Court of Appeals for the Eighth Circuit
remanded to the Agency the new source performance standards and the
pretreatment standards for new sources for the corn wet milling
subcategory of the Grain Mills Point Source Category (40 CFR 406.15
and 406.16) promulgated by EPA under Section 306 and 307 of the
Federal Water Pollution Control Act Amendments of 1972.
The new source standards for TSS and BOD were identical to those for
1983. They are based on the availability of the technology
underlying the 1977 limitations plus the addition of deep bed
filtration. The Court upheld the availability of the 1977
technology and the ability of that technology to meet the 1977
limits in new plants. However, it concluded that the record did not
demonstrate that deep bed filtration would achieve the incremental
reduction necessary to meet the new source standards.
Moreover, the Court held that the Agency's analysis of the costs
associated with the new source standards were deficient in two
respects. First, the capital and operating costs for the new plants
were not separately prepared but developed by reference to the
incremental cost of modifying existing sources to go from 1977 to
1983 levels. Second, the costs were based on 1971 prices.
The Court remanded the new sources standard for further
substantiation of both the technical aspects and the cost
calculations. The Agency was to promulgate revised standards and
additional supportive evidence for the present new source standards
within 120 days (i.e., September 2, 1975).
The purpose of this document is to provide supportive evidence for
EPA's tentative conclusion not to revise performance standards for
new sources in the corn wet milling subcategory of the grain mills
point source category in accord with the Court's remand order.
TECHNICAL BASIS
An extensive analysis was conducted of available data on the
application of activated sludge and deep bed filtration for
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treatment of various waste waters. Sources of data included the
literature, field inspections, special consultants, expert opinions,
corn wet milling companies, and equipment manufacturers. The review
focused on the technology identified by EPA to meet the New Source
Performance Standards; namely, good in-plant waste control and
maximum water recycling, activated sludge biological treatment, and
deep bed filtration. The data unequivocally and unmistakably
substantiates the fact that high strength biodegradable organic
wastes, such as those generated by corn wet mills, can be
successfully treated with biological treatment processes,
particularly complete mix activated sludge. With proper design and
operation of treatment facilities, a stable high quality effluent
can be attained on a reliable and sustained basis. The data
strongly support the new source performance standards as originally
promulgated.
Corn wet milling wastes may originate from a number of unit
operations in the wet milling processsteepwater evaporation,
modified starch production, and syrup refining as well as less
pollutant producing processes of feed de-watering, oil extraction
and refining, and general plant cleanup.
Waste waters from the industry can generally be characterized as
high-volume, high-strength discharges. Based on summary data from
12 of the 17 corn wet mills, BOD varies widely, from 255 to 4450
mg/1, with a corresponding range in COD. Those plants with very low
BOD5 values typically have barometric condensing systems using once-
through cooling water. At the other extreme, the very concentrated
wastes are from plants using recirculated cooling water (either
surface or barometric condensers).
Suspended solids levels in the total waste streams show similar
variations ranging from 81 to 2458 mg/1. The plants with low
suspended solids concentrations are those using barometric
condensers with once-through cooling water. The inter-relationship
of pollutant loads, pollutant concentrations, waste flow, and plant
production is discussed in Appendix A.
BOD5 in terms of raw material input (shelled corn) ranges from 2.1
to 12.5 kg/kkg (119 to 699 Ibs/MSBu) , and averages 7.4 kg/kkg (415
Ibs/MSBu). Similarly, the suspended solids in the total plant waste
waters range from 0.5 to 9.8 kg/kkg (29 to 548 Ibs/MSBu) and average
3.8 kg/kkg (211 Ibs/MSBu). These data emphasize again the wide
variation in waste characteristics from the corn wet milling
industry. The waste water flows vary from 3.1 to 41.7 cu m/Kkg (21
to 280 gal/SBu) with an average of 18.3 cu m/kkg (123 gal/SBu).
Those plants with lower waste flows per unit of production are those
that employ recircula-ting cooling water systems.
Most plants segregate their major process waste water from cooling
water prior to treatment. Once-through cooling water systems are
being replaced with recirculating systems, in several instances.
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In the development of New Source Performance standards for the Corn
Wet Milling Subcategory, a specific methodology was followed. In
determining representative raw waste loading for new corn wet mills,
a medium-sized mill with a daily grind of 1524 kkg (60,000 SBu) was
selected. This hypothetical mill would practice good in-plant
control and incorporate use of recirculated cooling water. The
waste water characteristics of this mill reflect actual industry
practice based on average data received from existing mills. These
waste water characteristics would be as follows:
Flow 11,355 cu m/day (3.0 mgd) (50 g/SBu)
BOD5 7.14 kg/kkg (400 Ibs/MSBu) 960 mg/1
Suspended Solids 3.57 kg/kkg (200 Ibs/MSBu) 480 mg/1
The pollutant potential of the raw waste discharge from a 60,000
SBu/day corn wet mill is equivalent to the untreated waste expected
from a domestic population of 138,000.
In the development of the new source performance standards, a number
of alternative treatment systems were identified for the
representative corn wet mill. The investment and annual cost for
each alternative, and the resultant pollutant load reductions were
identified (9).
The specific technology identified to facilitate compliance with the
recommended New Source Performance standard for the Corn Wet Milling
Subcategory, Grain Mills Point Source Category was a combination of
biological/physical treatment. For the Corn Wet Milling Subcategory
of the grain milling industry, the new source performance standard
and best available technology economically achievable comprise
improved solids separation following activated sludge or comparable
biological treatment. Improved solids separation can be represented
best by deep bed filtration although alternative systems may be
available. The "exemplary" technology includes 12 to 18 hours of
aerated equalization ahead of a complete-mix activated sludge
process with associated chemical feed, sedimentation, sludge
dewatering facilities (centrifugation), grit removal, pH adjustment,
nutrient addition, and deep bed filtration of the biologically-
treated effluent. BOD5 and suspended solids concentrations of 20 to
30 mg/1 and 10 to 20 mg/1 respectively, are expected in the effluent
from this series of treatment processes. These concentrations
correspond to effluent loads of 0.15 to 0.22 kg/kkg (8.3 to 12.5
Ibs/MSBu) of BOD5 and 0.07 to 0.15 kg/kkg (4.2 to 8.3 Ibs/MSBu) of
suspended solids. BOD5 and suspended solids reductions expected are
about 97.4 and 96.9 percent respectively.
In achieving the recommended new source performance standards
through this technology, deep bed filtration of biologically treated
waste attributes to an additional 50 to 75 percent BOD5 and
suspended solids removal beyond biological treatment, alone.
Biological treatment, alone, attributes to producing an effluent
before filtration of 75 - 125 mg/1 BOD5 and suspended solids, with
corresponding overall BOD5 and TSS reductions of 90 and 80 percent.
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In meeting the New .Source Performance Standard, the pollutant
potential of the representative plant is reduced from the equivalent
of 138,000 people to 6,700 people in terms of waste load.
In evaluating waste water control in the corn wet milling industry,
it is essential to evaluate both in-plant control measures and
effluent treatment systems. Good in-plant controls can greatly
reduce the total raw waste load and improve treatment plant
efficiency. Various in-plant controls identified for New Source
Performance Standards include:
1. Isolation and treatment of all process waste waters. No
process wastes should be discharged without adequate
treatment.
2. Elimination of once-through barometric cooling waters,
especially from the steepwater and syrup evaporators.
This change can be accomplished by recircalating these
cooling waters over cooling towers or replacing the
barometric condensers with surface condensers.
3. Isolation of once-through noncontact (uncontaminated)
cooling waters for discharge directly to the receiving
waters or provision of recirculating cooling tower
systems with the blowdown directed to the treatment
plant.
U. Installation of dikes at all process areas subject to
frequent spills in order to retain lost product for
possible reuse or by-product recovery.
5. Installation and maintenance of modern entrainment
separators in steepwater and syrup evaporators.
6. Surveillance and monitoring of major waste streams to
identify and control sources of heavy product losses.
7. Provision of extensive waste treatment for the resulting
process waste waters consisting of: flow and quality
equalization, neutralization, biological treatment, and
solids separation. The biological treatment methods
available i.nclude activated sludge, pure oxygen activated
sludge, bio-discs, and possible combination of other
biological systems.
8. Institution of maximum water reuse practices at all
plants over and above the current levels of practice.
9. Provisions to improve solids recovery at individual waste
sources.
In-plant housekeeping and good operation can have a major impact on
the raw waste loads from a mill. Diking of spill areas, monitoring
and careful operation have been reported to reduce raw waste loads
64
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by 25 to 50 percent in some plants. The combination of in-plant
controls and proper waste treatment constitutes a practicable means
for achieving the specific effluent limitations.
AND DETERMINATIONS
The end-of-pipe treatment technology recommended for new corn wet
mills, activated sludge and filtration, was reviewed within and
without the corn wet milling industry. The activated sludge process
has been proven as an effective treatment method in numerous
applications. These applications include municipal or domestic
wastes and high strength organic industrial wastes. Of particular
emphasis in this study were applications of the activated sludge
process to food processing wastes with characteristics similar to
those generated by corn wet mills. The data established the fact
that the activated sludge process can effectively treat these high
strength wastes and produce an acceptable long-term average effluent
quality.
In industries generating wastes similar to corn wet milling wastes,
such as brewing, distilling, and malting, the data show that
consistently high levels of effluent reduction are attained on a
long-term basis. High quality effluents with BOD and suspended
solids less than 30 mg/1 are consistently and routinely produced at
many treatment facilities. This has been demonstrated with a wide
variety of industrial wastes, including those generated by
breweries, edible oil refineries, malting plants, distilleries,
bakeries, wineries, and fruit and vegetable processing plants.
Within these industries raw waste loads range generally from 750 to
6700 mg/1 of BOD5 and 50 to 4000 mg/1 total suspended solids.
Biological treatment with or without filtration has been
demonstrated to result in overall BOD and TSS removals ranging
between 87 and 99.4 percent BOD, and 67.0 and 99.4 percent total
suspended solids, generally greater than 96 percent for BOD and
suspended solids. Effluent levels as low as 10 to 20 mg/1 BOD and
suspended solids have consistently been achieved. For purposes of
comparison of waste strength, corn wet milling wastes ranges between
250 to 4450 mg/1 BOD, and 80 to 2450 mg/1 total suspended solids.
Data and experience indicate that these industries are subject to
most of the same elements of waste load variability, waste strength,
and required treatment mechanisms as experienced within the corn wet
milling industry. In fact, a detailed statistical evaluation of raw
waste load variability for both the brewing and corn wet milling
industry performed in this study indicate an unmistakable similarity
in waste characteristics, waste load variability, and general nature
and biodegradability of the waste. Waste waters generated by two
breweries which now discharge treated wastes to navigable waters
substantiate the treatability of brewing waste to very high
pollutant reduction levels. Corn wet milling waste is not unique
among many food processing wastes, and presents no enigma in
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accomplishing high levels of treatment under present sanitary
engineering practice.
Activated sludge has yet to be applied to its fullest potential
within the corn wet milling industry because of poor in-plant waste
controls, design inadequacies, and operational deficiencies. If
these were eliminated, the activated sludge process could
successfully treat corn wet milling wastes and reliably produce an
effluent with BOD5 and TSS of 30 mg/1 or less on a long-term average
basis. The New Source Performance Standards can be met at an
existing corn wet mill employing present day technology.
peep bed filtration is a demonstrated and available technology. It
is universlly applied in the treatment of water supplies for
municipalities and industries and can produce effluents containing
essentially no suspended solids in these applications. Filtration
has been successfully employed in the treatment of municipal and
industrial secondary (biologically treated) effluents. The
literature, expert consultants, and other data clearly document this
fact. The process has been sufficiently demonstrated to enable the
development of meaningful design criteria and has been employed in
numerous applications. In municipal applications, a well designed
filter can be expected to reduce suspended solids by 80 percent or
more and to produce an effluent containing less than 10 mg/1 TSS.
Similar results can be anticipated with industrial wastes if the
preceding biological treatment system is well designed and operated.
It lias also been demonstrated that deep bed filtration performs as
an effective back-up system during periods of biological treatment
upset and thus helps to insure that a stable effluent will be
produced.
In addition to applications outside the corn wet milling industry,
filtration may be successfully applied to corn wet milling wastes.
The process has been demonstrated with other high strength organic
wastes. Expert opinion supports this applicability, as well as the
ability of a well designed treatment system to meet the New Source
Performance Standards, One corn wet milling company has
successfully applied deep bed filtration following biological
treatment on a full-scale basis. At Clinton Corn Processing Company
in Clinton, Iowa, filtration has been demonstrated as an effective
means of further reducing BOD and suspended solids levels in treated
corn wet milling effluent. Suspended solids reductions of 50 to 100
percent and averaging better than 75 percent were demonstrated with
deep bed filtration of treated corn wet milling wastes. BOD
reduction of up to 50 percent was demonstrated.
Industries that are either employing filtration or have successfully
tested and are installing filters include: steel manufacturing,
petroleum refining, brewing, corn wet milling, wine processing, and
food processing. Multi-media filtration has had particular
application in the petroleum refining industry, where at least three
refineries are known to successfully treat refinery waste waters
after biological treatment. These applications represent some of
the longest-term use of modern filtration facilities employed with
66
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biological treatment systems for treatment of strong industrial
waste.
The costs required for new corn wet mills of various sizes to meet
the New Source Performance Standards were reevaluated and are
indicative of current pollution control technology. These costs are
based on January 1975 dollar values and include waste treatment
facilities and necessary in-plant controls or cooling system
designs.
Based on an extensive review of technical data, the New Source
Performance Standards for the Corn Wet Milling Subcategory should be
implemented as promulgated on March 20, 1974. As the data
demonstrate, new plants employing best available demonstrated
control technology can readily achieve these standards.
A reasonable prediction of waste treatment facility performance at a
new corn wet mill indicates that the New Source Performance
Standards can be readily attained with currently available
technology. There is adequate provision in the standards for
anticipated fluctuations in effluent quality.
There are no increased economic costs, intermediate effects,
programatic or energy consequences expected as a result of the
technology reevaluation for the New Source Performance Standard.
Evaluation of the nonwater quality aspects of applying the
recommended technology indicated that energy, air pollution, and
solid waste impacts will be minimal.
Based on the above outlined study and analysis, the Administrator
has evaluated data and the performance of biological treatment and
deep bed filtration, waste load variability, industrial application
of pollution control techniques for grain processing as well as
similar types of wastes, and has concluded that the New Source
Performance Standards as originally promulgated are proper and well-
founded.
The Administrator has determined that the technology is available
and transferrable with reasonable prediction that the technology
will be capable of removing the increment required by the New Source
Performance Standards. The costs associated with the technology do
not preclude or adversely affect its effective use and application.
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REFERENCES
1. Sverdrup 6 Parcel, Literature Review on Deep Bed Filtration,
June 1975.
2. Letter to Mr. Charles F. Lettow, Record File 4823-EPA-2,
May 22, 1975.
3. Metcalf 6 Eddy, Waste5/ater_Engineering, McGraw-Hill,
New York, 1972.
4. Roy F. Weston, Inc., "Process Design Manual for Upgrading
Existing Wastewater Treatment Plants", for U.S. EPA Technology
Transfer, October 1971.
5. McKinney, Ross E. , Microbiology for Sanitary Engineers,
McGraw-Hill, New YorkT 19627
6. Nemerow, Nelson L.r Liquid Haste of Industry - Theories,
Practices f and Treatment, Addison-Wesley, Reading,
Massachusetts, 1971.
7. Busch, Arthur W. , Aerobic Bilogical_ Treatment of Waste Waters,
Oligodynamics Press7 HoustonT 1971.
8. U.S. EPA, "Draft Development Document for Effluent Limitations
Guidelines and New Source Performance Standards for the Miscel-
laneous Foods and Beverages Point source Category," March 1975.
9. U.S. EPA, "Development Document for Effluent Limitations Guide-
lines and New Source Performance Standards for the Grain Process-
ing Segment of the Grain Mills Point Source Category," March 1974.
10. Cook, Charles, Memorandum to John Riley - Fluctuations in raw
waste load BODS from two breweries, July 15, 1975.
11. issac, P. G. , "Malting Effluents," Effluent and Water Treatment
November 1969.
12. Smith, A. J. , "Waste Treatment in the Liquor Distilling Industry,"
, March/April 1972.
13. Burkhead, C. E. , Lessig, C. A., Jr., Richardson, T. R. ,
"Biological Treatment of a Distillery Waste," 23rd Industrial
Waste Conference, Purdue University, May 7-9, 1968.
14. McKee, J., "$300,000 Waste Treatment at McKee Baking," Baking
Industry, October 1972.
15. Pearson, E. A., et al, "Treatment and Utilization of Winery
wastes," Proceedings of the 10th Industrial Waste Conference,
Purdue University, May 1955.
69
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16. Schroeder, W. D., et al, "Biological Treatment of winery
stillage". Proceedings of the Uth National Symposium on Food
Processing Wastes, December 1973.
17. Ryder, R. A., "Winery Waste Treatment and Reclamation,"
Proceedings of the 28th Industrial Waste Conference, Purdue
University, May 1973.
18. "Winery Innovates Waste Treatment,11 Food Engineering.
June 1972.
19. Tofflemire, T, J., et al, "Unique Dual Lagoon System Solves
Difficult Wine Waste Treatment Problem", Water & Wastes
Engineering/Industrial^ November/December 1970.
20. Data on Taylor Wine Company waste treatment, Hammondsport,
New York, received from EPA July 3, 1975.
21. Data on Morton Frozen Foods waste treatment, Crozet, Virginia,
received from EPA July 18, 1975.
22. Data on fruit and vegetable processing waste treatment -
statistical analysis; effluent data on Southwestern Oil and
Refining, Corpus Christi, Texas; data on Welch Foods treatment
system, Brocton, New York; received from EPA July 10, 1975.
23. Brown, D. R., and Van Meer, G. L., "Biological Treatment of
Wastes from the Corn Wet Milling Industry," Final EPA Grant
Report on Pekin Waste Treatment, August 30, 1973.
24. west, A. W,, "Report on April 19, 1972 Investigation of the
Wet Corn Milling Waste Treatment Plant, CPC International Inc.,
Pekin, Illinois,"'EPA, Cincinnati, Ohio, May 1972.
25. Repta, R. J., "Activated Sludge Treatment of a Corn Wet Milling
Waste," M.S. Thesis, Illinois Institute of Technology, December
1973. (also titled Progress Report - Improve Pekin Waste Treat-
ment Plant I, November 1972 - February 1973.)
26. Correspondence with CPC International Inc., May 29, 1975.
27. Correspondence with CPC International Inc., June 6, 1975.
28. correspondence with CPC International Inc., June 9, 1975,
29. Roy F. Weston, Inc., "Process Evaluation Report for Upgrading
Existing Wastewater Treatment Facilities," for CPC International
Inc., Corpus Christi, Texas, March 15, 1975.
30. Memorandum - visit to CPC*s Corpus Christi corn wet mill. Record
File 4823-EPA-28, June 23, 1975.
31. Correspondence with American Maize-Products Company, June 18,
1975.
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32. Correspondence with American Maize-Products Company, June 9,
1975.
33. Correspondence with Anheuser-Busch, Inc., June 6, 1975.
34. Memorandum - meeting with EPA and corn wet millers. Record File
4823-EPA-29, June 23, 1975.
35. U.S. EPA, "Process Design Manual for Suspended Solids Removal,"
Technology Transfer Office, January 1975.
36. Weber, Walter J. , Jr., Phvsicochemical Process es for Water
Quality Control, Wiley-Interscience, New York, 1972.
37. Fox, David M. , and Cleasby, John L. , "Experimental Evaluation
of Sand Filtration Theory," Journal of the Sanitary Engineering
^ASCE, SA5, October~1966.
38. American Water Works Association, Inc., Water_2uality._and
, Third Edition, McGraw-Hill, New YorkT 197l7
39. Correspondence with Neptune Microfloc, Inc., June 24, 1975.
40. Cleasby, J. L. , and Baumann, E. R. , "Wastewater Filtration Design
considerations," U.S. EPA Technology Transfer Seminar Publication,
July 1974.
41. Hsiung, K. Y. , and Cleasby, J. L. , "Prediction of Filter Per-
formance," Journal of the Sanitary Engineering Division, ASCE,
94, December~19687
42. Lynam, B. T. , Ettelt, G. , and McAloon, T. , "Tertiary Treatment at
Metro Chicago by Means of Rapid Sand Filtration and Micros-trainers,"
Journal Water Pollution Control Federation , 41, February 1969.
43. Tchobanoglous, G. , "Filtration Techniques in Tertiary Treatment,"
Fe deration , 42, Apr i 1 1970.
44. Tchobanoglous, G. , and Eliassen, R. , "Filtration of Treated Sewage
Ef f 1 uent , " Journal of the Sanitary Engineering Division, ASCE,
April 1970.
45. Baumann, E. R., and Huang, J. C. , "Granular Filters for Tertiary
Wastewater Treatment," Journal Water^ Pollution ^Control Federation,
46, August 1974.
46. Gulp, G. L. and Hansen, S. P., "Extended Aeration Polishing
by Mixed Media Filtration," Water_and_ Sewage_Works ,
February 1967.
47. Culp, R. L. , arid Gulp, G. L., Adyancedjtfagtewater Treatment,
Van Nostrand Reinhold, New York, 1971.
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48. Vecchiolo, Jr., et al, "Wast.ewat.er Reclamation and Recharge,
Bay Park, New York," Journal Sanitary Engineering Division.
A§CE, April 1975.
49. "Ultra-High Rate Filtration of Activated Sludge Plant Effluent,"
EPA-R2-73-222, April 1973.
50. Middlebrooks, E. J., et al, "Evaluation of Techniques for Algae
Removal from Wastewater Stabilization Ponds,n Utah Water Research
Laboratory, Utah State University, Logan, Utah, January 1974.
51. Correspondence with Dravo Corporation, Water and Waste Treatment
Division, May 30, 1975.
52. Memorandum-discussion with Infilco-Degremont, Record File
4823-EPA-23, June 18, 1975.
53. Correspondence with General Filter Company, June 24, 1975.
54. Memorandum - discussion with Welch Foods, Record File
4823-EPA-17, June 17, 1975.
55. Memorandum - discussion with Robert Kerr Laboratories, Ada,
Oklahoma, Record 7ile 4823-EPA-21, June 18, 1975.
56, Savage, E. S. , "Deep-bed Filtration of Steel Mill Effluents"
Proceedings of 17th Ontario Industrial Waste Conference, Niagra
Falls, Ontario, June 7-10, 1970.
57. Data on deep bed filtration of refinery wastewaters: Amoco,
Yorktown, Virginia; Marathon Oil, Robinson, Illinois; Marathon
Oil, Texas City, Texas; received from EPA July 21, 1975.
58. Memorandum - discussion with Clark Oil and Refining, Hartford,
Illinois, Record File 4823-EPA-36, July 15, 1975.
59. Data on Welch Foods treatment system, received from EPA
May 30, 1975.
60. U.S. EPA, "Development Document for Effluent Limitations
Guidelines and New Source Performance Standards for the
Renderer Segment of the Meat Products and Rendering Process
Point Source Category," January 1975.
61. Baumann, E. R., "Design of Filters for Advanced Wastewater
Treatment," Project 1002-S, Engineering Research Institute,
Iowa State University, Ames, Iowa, June 1973.
62. Correspondence with Dr. E. R. Baumann, Iowa State University,
July 22, 1975.
63. Memorandum - meeting with Clinton Corn Processing Company on
June 2, Record File 4823-EPA-14, June 12, 1975.
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64. Correspondence with Clinton Corn Processing Company, June 17,
1975.
65. Memorandum - Clinton sampling results. Record File 4823-EPA-32,
June 20, 1975.
66. Correspondence with A. E. staley Manufacturing Company,
June 19, 1975.
67. Correspondence with CPC International Inc., June 26, 1975.
i
68. Brief for Respondents, Case 74-1448, U.S. Court of Appeals for
the Eighth Circuit, January 1975.
69. U.S. EPA, "Development Document for Proposed Effluent Limita-
tions Guidelines and New Source Performance Standards for the
Animal Feed, Breakfast Cereal, and Wheat Starch Segment of
the Grain Mills Point Source Category," September 1974.
70. Patterson, w. L., and Banker, R. F. , Black 6 Veatch Consulting
Engineers, "Estimating Costs and Manpower Requirements for
Conventional Wastewater Treatment Facilities," Report for the
Office of Research and Monitoring, U.S. EPA, October 1971.
71. Koon, J. H., Adams, C. E., Jr, Eckenfelder, W. W., Jr.,
"Analysis of National Industrial Water Pollution Control Costs,"
for Office of Economic Analysis, U.S. EPA, May 21, 1973.
72. Smith, Robert, "Cost of Conventional and Advanced Treatment of
Waste Waters," Federal Water Pollution Control Administration,
U.S. Department of the Interior, 1968.
73. Smith, Robert, and McMichael, W. F., "Cost and Performance
Estimates for Tertiary Waste Water Treating Processes,"
Federal Water Pollution Control Administration, U.S.
Department of the Interior, 1969.
73
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APPENDIX A
4
*
75
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APPENDIX A
EXPLANATION OF INTER-RELATIONSHIP OF POLLUTANT
CONCENTRATION, UNIT POLLUTANT LOAD, PROCESSING
RATE. AND WASTE WATER FLOW
The expression of pollutant loads in terms of concentrations (mg/1)
is useful for identifying and evaluating the characteristics and
performance of treatment measures for organic biodegradable wastes.
Concentration for biodegradable organic waste waters expresses a
commonality for comparison of waste water characteristics and
treatability results regardless of the source of the similar organic
biodegradable waste. For effluent limitations guidelines purposes,
the specific limitations are commonly expressed in terms of unit
pollutant per unit of raw material processed or product, whichever
is most applicable. The new source performance standards for the
corn wet milling subcategory are expressed as unit production of
pollutant e.g., BOD5 or TSS per 1000 standard bushels (MSBu) of
shelled corn (raw material). Concentration levels in terms of waste
loads can be related as follows:
Waste water concentration, mg/1 = U x P
8.34~x F
Where:
, U = unit pollutant load per unit of production,
Ibs/MSBu of shelled corn
P = Daily grind rate, MSBu of shelled corn/day
F = representative or actual flow rate, million
gallons per day (MGD)
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1-
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U.S. ENVIRONMENTAL PROTECTION AGENCY (A-107)
WASHINGTON, D.C. 20460
POSTAGE AND FEES PAID
ENVIRONMENTAL PROTECTION AGENCY
EPA-335
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