PB83-142133
Proceedings of the Conference on Combined Municipal/Industrial
Wastewater Treatment
Aharon Netzer
University of Texas at Dallas
Richardson, Texas
April 1981
U.S. DEPARTMENT OF COMMERCE
National Technical Information Service
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EPA-600/9-81-021
April 1981
PROCEEDINGS OF THE CONFERENCE ON COMBINED
MUNICIPAL/INDUSTRIAL WASTEWATER TREATMENT
Presented by
United States Environmental Protection Agency
Center for Environmental Studies
University of Texas at Dallas
Project Officer
Thomas E. Short, Jr.
Source Management Branch
Robert S. Kerr Environmental Research Laboratory
Ada, Oklahoma 74820
Editor and General Chairman
Aharon Netzer
University of Texas at Dallas
Richardson, Texas 75080
ROBERT S. KERR ENVIRONMENTAL RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
ADA, OKLAHOMA 74820
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
i, REPORT NO.
EPA-600/9-81-021
2.
ORD Report
3. RECIPIENT'S ACCESSI ON-NO.
4. TITLE AND SUBTITLE
Proceedings of the Conference on Combined
Municipal/Industrial Wastewater Treatment
5. REPORT DATE
Aoril IQfll (preparation date)
PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
Aharon Netzer, Editor
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
University of Texas at Dallas
Campbell at N. Floyd Road
Richardson, TX 75080
10. PROGRAM ELEMENT NO.
CBGB1C
R806799
12. SPONSORING AGENCY NAME AND ADDRESS
Robert S. Kerr Environmental Research Laboratory
U.S. Environmental Protection Agency
P. 0. Box 1198
Ada, Oklahoma
13. TYPE OF REPORT AND PERIOD COVERED
Final (3/25-27/80)
14. SPONSORING AGENCY CODE
EPA 600/15
15. SUPPLEMENTARY NOTES
16. ABSTRACT
This conference presented the latest information on combined municipal/
industrial wastewater treatment. The sessions were intended to bring together ex-
perts from the United States, Canada, Europe, and South Africa who have first-hand
experience in the field of combined wastewater treatment systems.
The conference was for all engineers, scientists, officials, and operators
who are involved in combined municipal/industrial wastewater treatment systems and
seek to improve their knowledge and understanding of advanced treatment procedures
for combined municipal/industrial wastewater treatment.
The curriculum of the Conference covered methods for treatment of combined
municipal/industrial wastewaters; industrial pretreatment; case histories of indus-
trial pretreatment effluents and combined municipal/industrial wastewater treatment;
data on presence and fate of priority pollutants in existing municipal/industrial
wastewater systems; research, design, and operation of combined municipal/industrial
wastewater treatment; sludge handling, utilization and disposal; water reuse and
recycling.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b. IDENTIFIERS/OPEN ENDED TERMS c. COSATI Field/Group
Industrial Wastes
Waste Treatment
Wastewater
Wastewater Management
Municipal Wastes
68D
91A
13. DISTRIBUTION STATEMENT
RELEASE TO PUBLIC
19. SECURITY CLASS (This Report)'
UNCLASSIFIED
21. NO. OF PAGES
556
20. SECURITY CLASS (This page/
UNCLASSIFIED
22. PRICE
EPA Form 2220-1 (9-73)
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NOTICE
Mention of trade names or commercial products does not
consititute endorsement or recommendation for use.
11
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FOREWORD
The Environmental Protection Agency was established to co-
ordinate administration of the major Federal programs designed
to protect the quality of our environment.
An important part of the Agency's effort involves the search
for information about environmental problems, management tech-
niques and new technologies through which optimum use of the
nation's land and water resources can be assured and the threat
pollution poses to the welfare of the American people can be
minimized.
As one of these facilities, the Robert S. Kerr Environmental
Research Laboratory is responsible for the management of programs
to: (a) investigate the nature, transport, fate and management
of pollutants in groundwater; (b) develop and demonstrate methods
for treating wastewaters with soil and other natural systems;
(c) develop and demonstrate pollution control technologies for
irrigation return flows; (d) develop and demonstrate pollution
control technologies for animal production wastes ; (e) develop
and demonstrate technologies to prevent, control or abate pollu-
tion from the petroleum refining and petrochemical industries,
and (f) develop and demonstrate technologies to manage pollution
resulting from combinations of industrial wastewaters or indus-
trial/municipal wastewaters.
The conference on Combined Municipal/ Industrial Wastewater
Treatment was held at The University of Texas at Dallas on
March 25-27 , 1980. This conference presented the latest informa-
tion on combined municipal/ industrial wastewater treatment. The
sessions brought together experts from the United States, Canada,
Europe, and South Africa with their first-hand experience in the
field of combined municipal-industrial wastewater treatment sys-
tems.
The curriculum of the conference included methods for treat-
ment of combined municipal/ industrial wastewaters; industrial pre-
treatment ; case histories of industrial pretreatment effluents and
combined municipal/ industrial wastewater treatment; data on
presence and fate of priority pollutants in existing municipal/
industrial wastewater systems; research, design, and operation of
combined municipal/ industrial wastewater treatment; sludge hand-
ling, utilization and disposal; water reuse and recycling.
Clinton W. Hall
Director
Robert S. Kerr Environmental Research Laboratory
iii
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CONTENTS
Foreword ill
Keynote Address, S. R. Reznek, "An Overview of EPA Joint (Combined)
Industrial Waste Research Program" 1
SESSION 1 7
J. G. Moore, Jr., "Innovation in Wastewater Treatment" 7
R. M. Southworth, "Industrial Categorical Pretreatment Standards" 16
S. Sacks, "Minimizing Costs by Good Financial Management". ... 24
SESSION II 31
A. W. Busch, "Compatibility Assessment of Municipal/Industrial
Wastewaters for Combined Biological Treatment" 31
E. L. Stover, "Biological Inhibition Screening of Industrial
Wastewaters" 45
D. F. Kincannon et_ _al_, "Treatment of Municipal Wastewaters Con-
taining Biologically Hazardous Industrial Compounds by
Conventional Activated Sludge and Extended Aeration". ... 60
J. van Leeuwen _§t_ _al_, "The Treatment of Combined Industrial and
Domestic Wastewater for Reuse in South Africa" 79
P. B. DeJohn jat_ al^ "Use of Granular Activated Carbon to Treat
Municipal Wastewater Receiving Industrial Flow" 93
J. L. Taylor, "Full Scale Experience with Activated Carbon
Treatment of Joint Municipal-Industrial Wastewater" .... 113
SESSION III 122
C. A. Pitkat, "Textile Waste Treatment at a Municipal PACT*
Facility" 122
R. G. Rice, "Review of the Use of Ozone for Improving Combined
Municipal/Industrial Wastewater Treatment" 141
A. J. Acher, "The Use of Solar Energy for Combined
Municipal-Industrial Wastewater Treatment" 167
C. E. Pound et al, "Land Treatment of Combined Municipal/
Industrial Wastewaters" 180
L. E. Sommers and D. W. Nelson, "The Utilization of Sewage
Sludges on Cropland" 188
Amatzya Eyal, "Utilization of Activated Sludge from Combined
Municipal/Industrial Wastewater Treatment for Animal
and Poultry Feed" 209
Preceding page blank
V
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SESSION IV
214
J. M. Craddock, "Water Pollution: Industry and Government
Working Together - A Case Study of Muncie, Indiana's
Industrial Pretreatment Program" 214
E. G. Wright et al, "The City of Chattanooga Industrial-
Municipal Pretreatment Program" 230
E. C. Monnig et_a^, "Investigations on the Suitability of
Various Pesticide Manufacturing Wastewater for
Discharge to Municipal Waste Treatment Facilities" 259
L. S. Directo, et_ al_, "Los Angeles County Experience in the
Control and Treatment of Industrial Wastewater Discharges" . 272
A. Netzer _et_ al, "Combined Municipal-Industrial Wastewater
Treatment in Garland, Texas" 30°
SESSION V 313
G. M. Doughty, "The Treatment of Cotton Waste in the Mersey
Basin" 313
A. W. Wilson, "Case Study of a Potato Chip Producer Discharging
to a Small Municipal Treatment System" 329
J. D. Lowry, "Joint Treatment Design and Operation Problems
with a Fine Paper Manufacturing Wastewater" 353
K. C. Bradley, "Uniroyal Chemical's Experience with Combined
Municipal-Industrial Wastewater Treatment at
Elmira, Ontario" 381
D. W. Pickard, "Industrial Compatibility with the POTW in
Tampa, Florida, through City/Industry Cooperation" 388
R. Seraydarian et al, "Sources of Toxic Pollutants Found in
Influents to POTW's" 395
H. D. Feiler et al, "Treatment and Removal of Priority
Industrial Pollutants at Publicly Owned Treatment
Works"
A. C. Petrasek, Jr., "Behavior of Selected Toxic Substances
in Wastewater Collection and Treatment Systems" 453
F. B. DeWalle et_ al, "Effect of Combined Treatment on
Priority Pollutants in POTW's" 478
R. A. Minear et al, "Heavy Metals in Municipal Wastewater
Treatment Plant Influents: An Analysis of the Data
Available from Treatment Plants" 488
K. J. Yost e_t_ _al_, "Sources and Flow of Heavy Metals and
Cyanide in the Kokomo Municipal Treatment System" 521
H. M. Jeffus, "Problems with Metals in the Residue from
Combined Municipal/Industrial Waste Treatment" 544
VI
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PBc.3-1421U1
KEYNOTE ADDRESS
AN OVERVIEW OF EPA JOINT (COMBINED) INDUSTRIAL
WASTE RESEARCH PROGRAM
S. R. Reznek
Deputy Assistant Administrator for Environmental Engineering & Technology
U.S. Environmental Protection Agency
Washington, D.C. 20460
INTRODUCTION
The subject of combined treatment is complex and, frankly, confusing.
I am not sure that I understand the Federal policies and programs exactly,
and I was part of their development. The issues and questions epitomize all
the issues and questions that make pollution control and environmental pro-
tection an
- interesting
- frustrating
- and generally cantankerous issue.
The source of the problem is the same as it is in everyone of our day-
to-day affairs. Not only do we not know all we need to know to make perfect
decisions, we have not even found out everything we could conceivably find
out before we make them.
How many of you read the catalog of universities you applied to before
selecting one? How many of us interview the university teachers? How much
study do we do before making a personal or corporate investment?
In the environment area, the lack of knowledge creates two dilemmas.
The first is related to time, i.e., more study or action now. Congress has
spoken on that point several times and usually the legislation demands action.
Second, decisions made without total knowledge will not be efficient. That
means they will be less cost-effective than they could be—could be in the
theoretical sense. Could be if we waited and studied. Could be if we did
not decide until later. Russell Train used to say:
(1) We are neither so poor that we cannot afford the costs of
pollution controls, nor are
(2) We so rich that we can afford not to pay the costs of pre-
serving our environment.
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These words remain true. However, we now have a 20% inflation rate.
The single indispensible material resource used in all manufacturing—
energy—is multiplying in price. I guess we are coming to realize that
Train's remarks have to be expanded to include:
(3) We are no longer so endowed with resources that we can afford
to waste them.
Pollution controls must be cost-effective and resources must not be used
in inefficient measures. Theoretically, I could design an efficient area-
wide wastewater management program. Let's look at the nature of the problem.
First, the system consists of many small discharges. All of them can dis-
charge to a central system, and some have the option of direct discharge.
All can control their water use and some can pretreat their wastewater before
discharging to the central facility.
The problem of defining the most economical configuration is extremely
complex. Environmental performance is determined by the net discharge of
pollutants and costs by the nature of technologies selected.
Now look at the real problem. Discharge does not simply mean biological
oxygen demand (BOD) and suspended solids. It now means four sanitary and
165 toxic pollution parameters. We don't know how to add them together pre-
cisely. Further, the interest, i.e., a toxic pollutant, will affect the BOD
removal efficiency. Most unfounding of all, it is not the time-averaged
toxic pollutant load that affects BOD removal performance, it is the time
variations and short-term high concentration conditions that actually affect
performance.
On the cost side, the real situation is more complex than simply total
cost. Costs are paid by municipalities for the collection systems and for
treatment plants. Costs are also paid by the industries for pretreatment.
Private and public bodies will obviously have different financing costs. The
Federal Government underwrites some of the municipal costs and, as usual, we
have rules—rules about recovering the Federal share for industrial treatment
and for having the municipalities set user fees to collect that share.
The real problem of protecting the environment is even more complex.
Wastewater treatment will create solid wastes. These sludges will have their
own implications for regional environmental quality and municipal and private
pollution control expenditures. So real problems are very complex, indeed.
Regional systems include numerous small discharges, a central treatment capa-
bility, the need to control the environmental impacts of over one hundred
pollutants, and the costs and environmental consequences of disposing of
municipal sludge and industrial treatment residuals.
Unfortunately, we do not know enough to design these systems in great
detail. But we do know enough to design good systems and to avoid gross in-
efficiencies. EPA's research program tries to generate the information nec-
essary for better decision.
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EPA RESEARCH PROGRAMS
EPA's industrial/municipal research is in four areas:
Combined treatment
Industrial pretreatment
Residuals management
Areawide industrial treatment
Combined Treatment
Joint treatment research involves the study of the combined treatment of
industrial and municipal wastewaters in the publicly owned treatment works.
Here, the concern is the effect the industrial contribution has on the muni-
cipal treatment system. Does the toxicity of these wastes reduce treatment
efficiency? What happens to various industrial components in the municipal
treatment system? Can these industrial components be biologically degraded?
Are they air-stripped into the atmosphere? Do they attach to the sludge
solids or do they simply move through the system and end up in the effluent?
The ultimate objective of studies in combined treatment is to develop a sound
understanding of the capacities of municipal treatment systems to reduce con-
ventional and toxic industrial pollutants.
Pretreatment
The pretreatment effort, as the name implies, involves the study of the
treatment of industrial wastes prior to their discharge into a municipal
waste treatment plant. A knowledge of pretreatment performance, coupled with
a knowledge of capabilities of municipal systems to handle industrial waste
components, can lead to the development of cost-effective pretreatment
guidelines.
Residuals Management
The treatment of wastewaters inherently generates waste solids or treat-
ment sludges. Some industrial pollutants, such as heavy metals, tend to con-
centrate in wastewater sludges. The effect of industrial components on the
characteristics of municipal sludges may be very critical in the considera-
tion in determining disposal options and costs. The industrial components
may make the sludges ecologically unsuitable for land application. Heavy
metals in the sludge may well be controlled to acceptable levels by pretreat-
ment of industrial wastewater.
There are other aspects of residuals production that must be considered.
Industrial pretreatment will also create a residual problem. Instead of
having a single source located at one municipal treatment plant, pretreatment
may create many small sources of residuals. These wastes have to be properly
managed. Areawide planning efforts should consider an optimum resource re-
covery scheme that will recycle these residuals. The institutional factors
of collection, transportation, and final disposal of pretreatment residuals,
along with industrial waste treatment residuals, are among the problems
studied in our "Residual Management" area.
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Areawide Industrial Treatment
While not widely practiced in this country, centralized industrial
wastewater treatment is often an economically attractive possibility. A
prime example of this concept is the Gulf Coast Waste Disposal Authority's
plants near Houston, Texas. In highly industrialized areas it may be eco-
nomically feasible to construct industrial sewers which transport industrial
wastewaters from several sources to a central treatment plant dedicated only
to industrial waste treatment.
Research Projects
For several years now, EPA's program has been involved in a number of
projects to help solve some of the problems of combined industrial/municipal
treatment. I would like to discuss some of EPA's active projects.
Allegheny Grants
In cooperative projects with Allegheny County, EPA will evaluate the
residual management problems and resource recovery potentials that exist in
the highly industrialized area near Pittsburgh, Pennsylvania. Waste Water
Treatment Sludges and other process residues air cleaning, and industrial
manufacturing are produced each day in Allegheny County. As residue quan-
tities increase and disposal options become more constrained because of new
laws and regulations, the cost will increase.
Steel mills and other primary metal industries, plating and coating
operations, foundries, nonferirous metals, and all add to the problems and
costs of waste.
The objectives of this study are to:
1. Determine distribution, volume, and characteristics of indus-
trial wastewaters and sludges in Allegheny County.
2. Determine best practical treatment for industrial sludge volume
and characteristics for area treatment plants.
3. Investigate possible future waste types and volumes.
4. Develop alternatives for collecting, disposing, and recycling
the area wastes.
5. Develop a complete county residual treatment management system.
Municipal and Flue Gas Desulfurization Sludges
The beneficial use of a waste material offers one of the best solutions
to sludge disposal problems. This was the goal of a cooperative project with
the Dravo Lime Company. The purpose of the project was to combine flue gas
desulfurization sludges with municipal sewage sludge to produce synthetic
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fertile soils. These soils could be used to reclaim land and, at the same
time, solve the disposal problems of these waste sludges.
During the project, over 240 different mixtures of municipal and flue
gas desulfurization sludges were prepared. Each mixture was tested for per-
meability, density, leachate composition, germination potential, and chemical
composition, including heavy metals analysis. The most promising artificial
soils were tested to evaluate their ability to support plant life. This
testing included monitoring of plant growth and heavy metals uptake by the
plants. The results of the study indicate that this type of synthetic soil
does have a useful application.
The Susceptibility of Metals to Treatment in Combined Systems
In a research grant project with the Illinois Institute of Technology,
we are evaluating the mechanism of metals removal in joint industrial/munici-
pal systems. In past efforts to develop pretreatment guidelines, surveys of
heavy metals removal in combined systems have not yielded consistent results.
Removal efficiencies ranging from zero to near 100 percent have been reported
for nearly all the metals studied. The objective of the project is to clari-
fy the relationship between the chemistry of wastewater and the extent of
metals removal and to develop a method of predicting metals removal.
The results of this study indicate that metals removal can be explained
by considering the chelating properties of the organic materials in the ef-
fluent and the ability of the biomass and the suspended solids to adsorb
metal species. Experiments have shown that operational parameters such as
sludge age can influence the chelating chemistry of the wastewaters and
sludges. The important parameters are, first, the types and quantities of
metals that are present and the presence of industrial chelating material,
such as cyanide. The most important factors affecting the chelating capacity
of the organic material in the effluent seem to be sludge age and the pres-
ence of digester supernatant.
Muncie Pretreatment Case Study
Pretreatment standards will require most municipalities to affect pro-
grams which are successful in reducing industrial discharges through publicly
owned treatment works. Muncie, Indiana, has had a very successful pretreat-
ment program in effect since 1972. Through a research grant, Muncie has
undertaken to produce a case study document as guidance to other communities
faced with similar problems. Elements of this case study will include: a
detailed description of the Muncie area, the motivating forces behind the
development of their program, the effects of legislation, their sewer ordi-
nances, industrial monitoring, their surcharge systems and cost recovery pro-
grams, enforcement, their sludge application program, water quality improve-
ment in receiving streams, the effects of pretreatment program on the waste-
water plant, estimates of the costs incurred by industry, and the industries'
choices to participate or build their own treatment systems.
In addition to the case study, Muncie will carry out a sampling study
of its system to determine the source of priority pollutants and to evaluate
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the fate of these materials during treatment. Also, they will evaluate the
residual management practives in their area.
1. They will identify the sources, transportation, and methods of
disposal for all industrial residuals generated within this
area.
2. Evaluate the effective means of maximizing resource recovery
and minimizing environmental impact and operating costs of
treatment.
Biological Simulation Monitor
In a grant with Vanderbilt University, we have undertaken to develop a
monitor which can evaluate changes in the influent in order to determine if
these changes will affect plant operation. A shock load from an industrial
contributor can destroy plant efficiency. A biological simulation monitor
provides a means of continuously monitoring the influent to a treatment
plant for variations in chemical or physical composition.
These studies involved a specifically designed continuous respirometer.
The biological simulation monitor system is an early warning system using a
laboratory scale activated sludge unit. The feed to the system is the treat-
ment plant's influent. Laboratory studies employing controlled feed to the
microorganisms have shown the biological simulation monitor system can give
a rapid response.
On-site testing at two treatment plants have corroborated the laborato-
ry results. During field testing, the biological simulation monitor was
able to indicate changes in the influent three hours before the flow reached
the aeration basins.
CONCLUSION
The projects that have just been discussed represent only a few of the
many that have been and are being undertaken by our industrial/municipal
research program. These were presented only to indicate some of the types
of studies that we are undertaking in an effort to solve the many problems
that exist in the industrial/municipal waste treatment area. I am sure that
in the future our Agency's efforts will continue to expand in this vital
area. The problems of an expanding list of "priority pollutants," residual
disposal, and the reuse and recycle of wastes will present future challenges.
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INNOVATION IN WASTEWATER TREATMENT
J. G. Moore, Jr.
Graduate Program in Environmental Sciences
The University of Texas at Dallas
Richardson, Texas 75080
TEXT
Innovative technology is something new, or changes in anything already
established, new things or methods. Is there really anything new or have we
seen much new in the development of treatment of wastewater? Have we seen
much new in the combined treatment of municipal and industrial wastewater?
I think not. I have been involved in water pollution control since the mid
1960's. There have been enormous sums spent in research and development at
all levels of government, and I'll have to say that I am pessimistic that we
will develop much dramatically new in terms of wastewater treatment. Now
that should give you a good beginning, since there are those who will talk
about innovation and wastewater treatment.
To some degree, I think the regulatory structure under which we in the
United States currently work militates against the development of innovative
or dramatically new technologies. I think combined industrial and municipal
wastewater treatment offers an example of the complications that arise in
attempting to advance the way we do things. Prior to the passage of Public
Law 92-500 in 1972 there was much encouragement for combined municipal in-
dustrial treatment; there was a deliberate national policy that joint treat-
ment would be encouraged. There were imagined, or claimed, or stated advan-
tages of combined municipal industrial wastewater treatment, one being an
economy of scale so that the cost both to the municipal resident and to the
industrial discharger would be less than if each discharged separately.
There was a concept of the dispersion effect of combined wastewater treatment
where industrial waste distributed through municipal systems could be ade-
quately treated or dispersed, so to speak, diluted perhaps, in the treatment
process. There was, in terms of local financing perhaps—where there were
industrial user charges—a concept that the municipality would have to fi-
nance that share of the treatment facilities with the charges collected from
industries. Public Law 92-500 and subsequent statutes at the Federal level,
of course, have further restricted the application of combined industrial-
municipal wastewater treatment from major facilities. First the requirement
for pre-treatment and secondly, the industrial cost recovery and user charge
systems have tended to reduce the advantages of combined municipal-industrial
wastewater treatment.
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So you will have no misunderstanding about where I stand, the concept
of industrial cost recovery was a ridiculous idea to begin with and has
become more ridiculous as the years have passed. There was an equity theory,
largely advocated by Leon Billings on Senator Muskie's staff on the Sub-
committee on Environment of what was originally the Senate Public Works
Committee, that somehow or other the industrial cost recovery idea was an
equitable approach to the differential that might exist between the cost for
an industry discharging directly to a stream and the industry discharging
through a municipal system. Whatever imagined advantage may have been en
joyed by the industrial discharger into a municipal system has largely been
erased—in fact, it may now be more expensive to go through a municipal system
than it would to discharge directly—has largely been erased by the indus-
trial cost recovery concept and pre-treatment regulations being issued by the
Environmental Protection Agency. The industrial cost recovery concept has
not yet been fully implemented yet, since Congress itself has postponed the
effective date repeatedly. Legislation is now pending in the House that
would eliminate the industrial cost recovery concept from Public Law 92-500
and the Clean Water Act of 1977. The major disadvantage, as far as I'm con-
cerned, to the industrial cost recovery idea is that whatever money may
eventually reach the Federal Treasury for that share of the cost of municipal
wastewater treatment planned to accomodate industrial waste will be consi-
derably offset by the cost of the multiple audits and bookkeeping that has
to occur at the local, state, and federal levels to account for that rela-
tively small percentage of the total cost of most municipal systems. In
other words, if there were a cost accounting of the industrial cost recovery
system, the chances are we would discover that, in total, the Federal Govern-
ment is losing rather than gaining money from the industrial cost recovery
concept. A report, commissioned by the Environmental Protection Agency and
done at their expense, recommended that the industrial cost recovery system
be eliminated, but the Environmental Protection Agency (EPA) has not yet
embodied that suggestion in legislation. EPA has generally gone to the Con-
gress with the position that industrial cost recoverv should be continued.
One of the effects, I think one of the inevitable effects, of the combined
industrial cost recovery and user charges for maintenance and operation ex-
penditures will be to reduce industrial water use. I don't think there is
any doubt that, over time,there will be a gradual reduction in water use by
industries that discharge into municipal systems. This may have some in-
teresting kind of side effects. For example, in Detroit, where the first
major rate increase for maintenance and operation expenditures has just been
imposed,my guess is that industrial water use will decline somewhere between
15% and 25% in the next two years. This means that the income on the water
supply side of the Department's operations may well decline, and it certainly
means that in the long run, on the wastewater treatment side the income may
decline. Thus, the cost will probably be redistributed among the other users
of the system, since the capitalization of the system has already been es-
tablished.
Another impact on combined municipal-industrial treatment is the pre-
treatment requirement. Despite the fact that pre-treatment regulations were
supposed to have been issued six or eight years ago, not all the pre-treat-
ment regulations are yet out—that is, the requirements for pre-treatment by
industrial category—and the conclusion that pre-treatment had to be equal to
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the "best available technology economically achievable" under the 1972 amend-
ments (and a similar approach to pre-treatment requirements today) almost
eliminates any economic advantage to the industrial dischargers through muni-
cipal systems. For example, if the pre-treatment regulations are, in effect,
the same as what would have been required for the 1983 Phase II effluent
limitations, and an industry must in addition pay the volume charges and the
strength charges for whatever remaining wastewater goes into the municipal
system, the chances are that the cost will be greater for the industry to
discharge into the municipal system than it would be if it discharged direct-
ly into the receiving water. Admittedly, a lot of industries in a lot of
places are captives of the system—that is to say, there is no available
place into which they can discharge. In Detroit, where the major concentra-
tion of industry is related to the production of automobiles, obviously a
direct discharge within the city would be extremely difficult, particularly
for the wastes that are generated in that industry. If a discharge by muni-
cipal systems is into "water quality limited waters," as opposed to "effluent
limited waters," as classified by the Environmental Protection Agency; the
cost could be even greater. Simply because the publicly owned treatment
works may have to meet, for those perameters that are affected by the waste,
strict requirements than might otherwise be imposed if they were located in
a less populated area of people and industry, pre-treatment costs may be con-
siderably higher.
Leon Billings has another concept that has permeated the Federal Water
Commission Control Act and that is that pollutants are really just resources
out of place. That is, if we could just find a way to get them back where
they belong, we would not have any waste. That's sort of believing if you
keep on burning a fire in your fireplace, you will eventually burn up all the
ashes; and those of you who have fireplaces know that is an impossibility.
There is always a residual, and the chances are that there will always be a
residual, for which no one has any use at all. It may be merely a substance
that accumulates in a very small quantity somewhere, but nevertheless, there
is some ultimate residual. Not everything is capable of being completely
recycled. Nevertheless, the combination of industrial cost recovery require-
ments and pre-treatment requirements undoubtedly means that industries which
pay attention to their costs will inevitably attempt to find ways to recycle
those substances that are in their waste streams. By the way, that may in
the long run be the most cost effective way for industries to dispose of the
pollutants that would otherwise be in their discharges. It is important for
industries to recognize that cost effectiveness is a relative question, that
the disposal of wastes should be constantly analyzed. The mere fact that it
was determined three years ago, or five years ago, that a particular scheme
for the disposal of the residuals was not cost effective does not mean that
the same circumstances hold true today. With both pre-treatment requirements
and effluent limitations for direct discharges becoming more and more strict
as we move into the future, the chances are the costs will be higher and
higher. As the costs of the discharge of substances becomes higher, the
possibility for gaining by recycling may be inevitably more economic, in the
cost effective sense, than it might be today, so the matter must be reviewed
constantly by an industrial discharger.
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Frankly, in my view, the most complicated questions facing all of us in-
volved in water pollution control—and to some degree in air pollution con-
trol too—is the disposal of that final residual that will always remain.
The current schemes for control have largely ignored the rising mountain of
sludges and residuals all over the U.S. The restrictions upon the disposal
of solid wastes are an unplowed field in terms of water or air pollution con
trol, which is to say, whatever restrictions we have felt are strict, under
the air and water pollution control acts, are nothing like what we will see
in the control of sludges. One obvious consequence is that as the levels of
required treatment increases, the volume of sludges will also multiply. For
the municipal wastewater treatment plant, the volume of sludges is enormous.
Today in Detroit, we are averaging a flow in the range of 600 million^
gallons a day through a wastewater treatment plant that is not yet performing
to secondary treatment levels—remember, we generate 35 hundred tons of wet
sludge daily. Existing incinerators are unable to burn that thirty-five
hundred tons, and we are currently hauling an average of 15 hundred wet tons
a day of sludge. At present, there is only one disposal site to which
Detroit sludge can be hauled, and before it can be hauled there, it must be
neutralized with lime and the solid content must be increased to 40% by the
addition of the ash—from the incineration process—which means that we must
conduct a mixing process between the final dewatering step and the disposal
of the sludge. The City has spent between 8 and 10 million dollars during
the last twelve months attempting to locate sludge disposal sites in the
state of Michigan; we have had sludge hauled illegally into Pennsylvania and
illegally into Ohio, and disposed of illegally in the state of Michigan.
If you think the problem is complicated today, the estimate is that
Detroit must plan for the ultimate disposal of somewhere in the range of 8
to 10 thousand tons of sluge per day at 22% to 25% solids for the next five
years. The annual budget for sludge disposal over and above the cost of in-
cineration for the Detroit Water and Seweage Department is 13 million dollars.
That does not cover the cost of evergy for incineration nor does it consider
the capital investment or the debt of service on the capital investment, that
is being expended to achieve more effective incineration and more effective
air pollution control. The City is faced with the prospect of the expendi-
ture of something in that range each 12 months indefinitely into the future
for the disposal of sludge.
What can be done? There is now pending in the Michigan Department of
Natural Resources a set of regulations, the net effect of each would be to
classify Detroit municipal sludge as a hazardous waste, under a state
statute. Some of you may know that the Environmental Protection Agency had
an internal battle of some magnitude between those responsible for wastewater
treatment and those responsible for solid waste disposal as to the classifi-
cation of municipal sludge as hazardous at the Federal level. After an
enormous expenditure of energy, the wastewater treatment side won, and muni-
cipal sludge was not declared to be hazardous. The Michigan Department of
Natural Resources says that, under the state statute under which the regula-
tions are being developed, they have no alternative but to promulgate the
regulations as presently drafted. There are no approved hazardous waste
disposal sites in the state of Michigan. Now if you want to contemplate an
10
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enormous problem think of forty thousand tons of wet hazardous sludge. My
recommended solution to the Mayor of Detroit is, if the regulations do become
effective, that Detroit haul its sludge to the Capitol grounds in Lansing.
We are fortunate—they are fortunate in Michigan—Detroit may be fortunate—
that before the regulations can go into effect, they have to be endorsed by
the joint House-Senate Rules Committee. The legislature is predominantly
Democrats; the Governor is Republican; the Detroit Mayor is Vice-chairman of
the National Democratic Executive Committee, but he has an unusual working
relationship since the Mayor was able to get the Republican, but not the
Democratic, Convention in Detroit. We have a Republican Judge who was Eisen-
hower's campaign manager in Michigan some years ago, who was appointed by
President Nixon to the Federal bench; thus we have a Republican Judge, a
Democratic Mayor, and a Republican Governor working to change the regulations
in the Rules Committee of the State Legislature, which is Democratic. We
have told the Michigan Department of Natural Resources that that is the way
we will go. Don't ever forget, everything has to be somewhere. If we can't
burn it—and we might not be able to burn it if it is declared a hazardous
waste—if we can't burn it, and we can't bury it, but we have to remove it
from the water, we have to put it somewhere. By the way, there is no place
on the Detroit Wastewater Treatment Plant site to put dewatered sludge. A
year ago at this time there were between 10 and 15 tons of frozen sludge on
that Plant site. They didn't have room for it then. There were piles, gen-
erally 4 to 5 foot high, alongside every road on the treatment plant site,
between all the buildings, and piled up on the back side of the treatment
plant site at a place where they intend to build primary clarifiers—an enor-
mous mountain of frozen sludge, and then came the spring's thaw.
One possible solution for sludge disposal sites is State responsibility
for their location and permitting. When I say State responsibility, I mean
that a State agency should take the lead in locating, establishing, and per-
mitting waste disposal sites. Detroit will have very little success finding
disposal sites for Detroit sludge. Nobody outside Detroit wants that sludge
from those people in Detroit deposited in their neighborhood. Even the sub-
urbs that send the major part of that sludge to the Detroit wastewater treat-
ment plant don't want it back in the suburbs. Of course, facetiously, one
could always say the solution may be to just hold it.
If you think the problem is complicated now, the Michigan Department of
Natural Resources is also planning to require that Detroit, or was planning
(I hope we have avoided it.) to require the Detroit sludge to be tested for
every pollutant on EPA's priority pollutant list, which now numbers some 150,
and inevitably will increase as time passes. There are some listed pollu-
tants for which there is not even yet a testing methodology.
Well, sludge is a problem; and sludge is a problem for combined systems,
The Detroit system has roughly 25% of the wastewater from industries, and
the industries from which it takes the waste are often the most complicated
ones in terms of treatment. As you might expect, Detroit has a large number
of electroplating plants of all kinds and their wastewater comes into the
Detroit system. There is, as yet, no pre-treatment program effective in
Detroit, but one is being developed according to the schedule presently pro-
vided in Federal regulations. Water reuse may, in time, cause us to pay more
11
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attention to some of the pollutants that we now leave in the water. That may
not necessarily help much, because if we manage to remove them from the water,
we merely have them somewhere else. In other words, the emphasis across the
country on water reuse may provide some benefit in terms of the treatment
process but it will not simplify the disposal of pollutants, where we are
more likely to get water reuse in those industries that decide that is the
way to reduce the cost of treating their industrial waste discharge.
Where is the opportunity for innovation in all of this process? The
chances are that the opportunity for innovation will lie in pre-treatment of
industrial wastewater and not in the treatment of combined municipal^-Indus*-
trial wastewater. In my view, the chances are that the greatest opportunity
for innovation will lie not in the wastewater treatment process but in the
very production process itself. The most enlightened industries in the coun^
try will be those which decide that they will, in so far as possible, ap^-
proach that ultimate goal that has been so widely acclaimed, no discharge of
any pollutants. I suspect that the industries that survive and prosper in
the longest run will be those which change the production process itself, in
order to reduce both the volume of wastewater discharge and the volume of
pollutants in that wastewater. If that means recycling, that will be the
focus of the activity. If that means reuse, then that will be the focus of
the activity. But there are imaginative minds conscious of the cost that
know in the long run it is the production process itself which must b~e chang^
ed in order to reduce the total cost.
I am going to provide some suggestions for the various parties that are
represented here. I always like to do this because I can tell people what
they ought to do without having any responsibility for the outcome. My first
one is for the EPA. The EPA should decide, at the national level, whether it
favors or opposes combined municipal-industrial wastewater treatment or
whether there is no real policy and it's not going to address the question
one way or another. My view is that the Agency has, in effect, through its
application of regulations under the existing statutes, actually discouraged
combined municipal-industrial wastewater treatment. I think the EPA should
tell the Congress that the industrial cost recovery provisions of the exist-
ing statute are impossible to administer and do not return a significant sum
of money to the U.S. Treasury when measured against the total administrative,
accounting and auditing costs and that it should be eliminated from the sta-
tute. Whatever presumed advantage there may be for the industrial discharger
into municipal systems is eliminated by the cost of the recovery of the Fed-
eral share, the pre-treatment requirements and the user charges for opera-
tions and maintenance imposed on industrial users. I doubt seriously, at
this point in time that it has made a significant difference in cost to the
industry, or would make a significant difference in cost to an industry,
whether it is located within or without a municipal system. For the states
I have a question. Are you prepared, in the long term, for redistribution of
the major industries in your state so that they become direct dischargers
rather than being located within the jurisdictions of publicly owned treat-
ment works? I think that is the inevitable result of the current policy
Admittedly, a lot of industries are captives of the publicly owned treatment
works system. But, they won't be forever, because industry does not remain
12
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static or constant. It will have opportunities to disperse; as industrial
facilities become old and production processes become out of date, there are
opportunities to close those facilities that are old and out of date, I sus-
pect that, in the future,, one of the considerations for the location of in-
dustrial facilities will be an attempt to locate in areas that are not water
quality limited and outside the jurisdiction of publicly owned treatment
works so that they do not have to go through one additional level of regula-
tory administration to meet water quality or wastewater treatment require-
ment s.
For industries, I believe you should constantly review the cost effec-
tiveness of your wastewater treatment systems and particularly examine the
question of residuals disposal. You see, we have not truly destroyed pollu-
tants anywhere in this country. They still exist, despite what you often
see in the news media. We are merely moving them around. We took them out
of the water and, in some cases, put them in the air. We have taken them
out of the air and, in some cases, put them in the water. Now the sink we
are using, whether we like it or not, is the land. There will come a time
—and we are rapidly approaching it—when we won't be able to put them in the
land, either. So as the regulations becomefflare and more strict, the cost
effectiveness of the various alternatives available to industry change. One
of the things industry should continually examine is can you save money by
becoming a direct discharger and moving your facility outside the jurisdic-
tion of a publicly owned treatment works? You can be certain that whatever
the requirements are today, they will be more strict in the future, and if
you are planning for a ten or twenty-year time span, you should make the de-
liberate assumption that whatever effluent limit you have today will be more
rigid in those years than they are now. The regulatory process will be more
restrictive; there will be more you are told to do than you are now told.
You should build that into your long range planning. For the present, can
you recover and reuse pollutants now in the sludge, or the wastewater? Can
you recycle the water so that you reduce your total water use? And, finally,
remember if the pretreatment process works, we have not again destroyed
pollutants; we have merely moved them someplace else. The industrial plant
site is the place to which we have moved them; instead of a large volume of
industrial sludge mixed with a large volume of municipal sludge, we will
have little piles of industrial sludge all over the landscape at industrial
plant sites. The question then is, what will be done with those little piles
of highly concentrated industrial sludge? The chances are for the most com-
plex industries, it's likely to be hazardous. There will have to be some
disposal site for hazardous waste. Or you could, I presume, do like some
industries have done, merely stack it on your plant site until you go out of
business, and then leave it to be disposed of by the government. We have
not destroyed it, we have merely moved it. The pre-treatment process merely
distributes it over the jurisdictional area of the publicly owned pre-treat-
ment works. Residuals will merely accumulate in smaller quantities, in
higher concentrations, in different places. We have not solved the disposal
question. Instead of Detroit looking for one site to put municipal sludge,
there will be 150 to 200 major industries scrambling all over one another to
find industrial sites for the disposal of industrial sludge. You must con-
sider, as an industry, what the ultimate cost may be for that residual, those
ashes that you have in the fireplace, that you can't put anywhere else.
13
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For municipalities, you face some interesting questions. What would be
the financial effect of a reduction in your industrial water sales if you
sell water as well as treat waste water? Because the effect of pre-treatment
requirements, industrial cost recovery and user charges is to encourage in-
dustries to reduce their purchases of water by recycling the water within the
system. In a similar vein, for those responsible for wastewater treatment
systems alone, what would be the effect of a reduction in the volume and^con-
stituents of the waste water you do receive? In other words, if industries
decide it is more cost effective to recycle or recover the resources and in
the process reduce the basis for their industrial rates, their payments to
you as a wastewater collector and treater will decline; what effect will that
have on the financing of your wastewater collection and treatment system? It
is conceivable, if industries are imaginative and innovative in what they do
in pre-treatment and resource recovery, that the rates for municipal users
will have to be increased to accomodate the reduction in industrial waste
discharges because the capitol investment in the system has already been made
and the chances are that any reduction in the quantity of wastewater may not
be matched by a similar reduction in the annual maintenance and operation
cost for the facility. The cities, municipalities and political subdivisions
that do treat wastewater and supply water to industries may face some in-
teresting financial problems in the long run. Another question for munici-
palities is do you really want the long range administrative burden of col-
lection and enforcement for the pre-treatment requirement and the industrial
cost recovery funds, as well as the user charges? In other words, do you
wish to be somewhere in that chain between the industrial user and the U.S.
Treasury to assure that small increments of whatever cost the industrial
facility represents gets back to the Treasury?
For those in the academic field, in my view, toxicology is probably the
major area for employment opportunities in the years immediately ahead.
Nobody knows for sure yet what all the toxic substances are in solids or in
wastewater or in sludge—residuals. There are two statutes the full effect
of which has not yet been felt—the Toxic Substances Control Act and Resource
Conservation and Recovery Act. Are you in your academic programs preparing
students to cope with these questions? Industrial wastewater treatment and
therefore, to some degree, industrial production processes, may also be ex-
panding fields. That is, are you producing graduates who understand the
connection between production processes and the generations of pollutants
including those in the residuals? The whole question of solid waste remains
to be solved; there will be increasing needs for persons who understand
groundwater hydrology and geology, as well as toxic substances. Residuals
remain a largely unsolved problem for those interested in the improving of
the environment.
As a final observation, I began by saying I was pessimistic as to the
chances for innovation as a result of the large volumes of governmental
research. I'm also pessimistic as to the future of combined municipal-
industrial wastewater treatment. My prediction is that the volume of indus-
trial wastewater discharged to publicly owned systems will decline in the
years ahead, and therefore the need for solving combined municipal-industrial
wastewater treatment problems will also decline. In other words, when indus-
tries are able to identify the full costs of discharging into publicly owned
14
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treatment works, they will more and more, as they have an opportunity, seek
places where they can discharge without having to pay those costs.
15
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PB83-1U2166
INDUSTRIAL CATEGORICAL PRETREATMENT STANDARDS
R. M. Southworth, P.E.
U.S. Environmental Protection Agency
401 M Street, S.W.
Washington, D.C. 20460
INTRODUCTION
In 1972, Congress passed the Clean Water Apt Amendments of 1972 (P.L.
92-500), one of the most comprehensive environmental laws ever enacted.
P.L. 92-500 divided effluent limitations from point sources of pollution into
three categories: municipal (domestic wastewater), industrial, and toxic.
The U.S. Environmental Protection Agency (EPA) was directed to establish uni-
form national standards, i.e., secondary treatment, for publicly owned treat-
ment works (POTW) and to establish best practical technology economically
achievable (BPT) standards for industrial categories. Both sets of standards
had to be complied with by July 1, 1977. In addition, EPA was directly to
establish best practicable waste treatment technology (BPWTT) standards for
POTWs and best available technology economically achievable (BAT) standards
for industrial categories, both of which had a compliance date of July 1,
1983. EPA was to also establish toxic pollutant effluent limitations on a
pollutant by pollutant basis using a complicated administrative procedure.
Because of that complicated administrative procedure and because of the
difficulty in determining which pollutants were toxic, delays occurred in
establishing limitations for toxic pollutants. EPA moved slowly, therefore,
to establish those limitations.
The Natural Resources Defense Council (NRDC) and other citizen groups
sued EPA because of the delay in promulgating toxic pollutant limitations.
As a result, a Consent Decree was issued by the U.S. District Court in
Washington, D.C., in June 1976, that required EPA to establish BAT limita-
tions, new source performance standards, and pretreatment standards for 65
specified toxic pollutants by December 31, 1979. The compliance date for
those limitations and standards was July 1, 1983.
In 1977, Congress passed the mid-course correction to P.L. 92-500, i.e.,
the Clean Water Act of 1977. The new Act established three categories for
industrial pollutants.
Conventional pollutants are defined as biochemical oxygen demand, sus-
pended solids, fecal coliform, pH, and other pollutants specified by EPA.
16 "
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Treatment of those pollutants by best conventional technology (BCT) is re-
quired by July 1, 1984.
Nonconventional pollutants are all pollutants not classified by EPA as
either conventional or toxic. Treatment by the best available technology is
required by 1984.
The new Act specified an initial list of toxic pollutants to which EPA
could add or subtract pollutants. That list was based on the 65 pollutants
specified in the 1976 Consent Decree. EPA refined the Consent Decree list
into 129 specific compounds. The new Act extended the court-imposed deadline
for promulgation of toxic pollutants limitations to July 1, 1984, and re-
quired treatment by the best available technology by that date.
The BAT toxic pollutant limitations apply to direct discharges, i.e.,
discharges to a body of water. Similar limitations apply to indirect dis-
charges or discharges to a POTW. EPA is required to establish categorical
pretreatment standards by either industrial category or subcategory for in-
direct discharges. Those standards apply uniformly to all industries within
the industrial category or subcategory.
This paper discusses the categorical pretreatment standards currently
being developed by the Effluent Guidelines Division, which is in the Office
of Water Regulations and Standards. It includes a discussion of the pre-
treatment requirements in the Clean Water Act of 1977, a discussion of EPA's
general pretreatment regulations, and a discussion of the procedure used to
establish categorical pretreatment standards. In addition, it discusses a
study that is currently being conducted by EPA to determine the fate of toxic
pollutants in POTWs.
CLEAN WATER ACT OF 1977
In the 21 major industrial categories, there are many thousands of dis-
charges to POTWs known to cause significant problems by:
- Interfering with POTW operation, i.e., causing fires, corrosion,
explosions, hazardous fumes, and system upsets;
- Passing through the POTW.
- Otherwise being incompatible with the POTW, e.g., interfering
with sludge disposal.
Section 307(b) of the Clean Water Act prohibits the discharges of pollu-
tants to a POTW that interfere with, pass through, or otherwise are imcom-
patible with a POTW. EPA is required to define interfere with, pass through,
and incompatibility and to establish pretreatment standards that prohibit the
discharge of pollutants that violate those definitions. EPA's pretreatment
regulations provide information on how to implement Section 307(b).
17
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PART 403 PRETREATMENT REGULATIONS
General Pretreatment Regulations were published in the Federal Register
on June 26, 1978, and were revised on October 29, 1979. Those regulations
discussed what is required for a pretreatment program and established two
types of pretreatment standards: prohibitive discharge standards and cate-
gorical pretreatment standards.
Prohibitive discharge standards apply to all users of a POTW whether the
user is subject to national pretreatment standards or to any state or local
pretreatment requirements. Those standards are expressed in general terms
and prohibit:
Pollutants that create a fire or explosion hazard in the POTW.
Pollutants that cause corrosive structural damage.
- Solid or viscous pollutants in amounts that cause obstructions
in sewers or interfere with the operation of the POTW.
- Pollutants at a flow rate and concentration known to cause or
that may cause interferences with the POTW.
- Heat in amounts that inhibit biological activity in a POTW.
The authority that establishes the local pretreatment program is responsible
for establishing specific limits for the prohibitive discharge standards.
Categorical pretreatment standards are national standards established
by the Effluent Guidelines Division for industrial categories or subcatego-
ries. Those standards specify quantities or concentrations of pollutants or
pollutant properties that may be discharged to a POTW. They are in addition
to the prohibitive discharge standards and are applied uniformly on a nation-
al basis. If categorical standards exist for an industry and that industry
discharges to a POTW, the local pretreatment program must require the indus-
trial to meet the categorical standards except under circumstances discussed
in the pretreatment regulations, i.e., credits. The procedure used to estab-
lish categorical pretreatment standards is discussed in the next section.
CATEGORICAL PRETREATMENT STANDARDS
The Clean Water Act Amendments of 1972 and the Clean Water Act of 1977
both established the principle of uniform national controls for industrial
pollution sources and specified that effluent limitations for those sources
be based on the technological and economic capabilities of the industries to
treat their wastewater. EPA's policy is, therefore, to establish uniform
effluent limitations for both direct and indirect discharges. This section
discusses the procedure used to establish categorical pretreatment standards
for indirect discharges.
The philosophy behind establishing uniform categorical pretreatment
standards is that all industries in a category or subcategory should have to
18
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treat their wastewater to the same degree of treatment. This prevents indus-
tries from "shopping around" to find a location where pretreatment standards
are the least stringent and allows EPA to promulgate limitations that are
manageable.
Categorical pretreatment standards are technology based standards. They
are based on the degree of treatment that can be obtained by different tech-
nologies considering the economic impact of those technologies. They are not
based on water quality considerations. The fact that the categorical pre-
treatment standards are not water quality based standards is one reason why
those standards can be applied uniformly on a national basis.
The first step in the procedure used to develop a categorical pre-
treatment standard is to prepare a development document. That document char-
acterizes the industry's wastewater, estimates the amount of wastewater gen-
erated, identifies wastewater constituents suspected of passing through or
interfering with POTWs, screens wastewater treatment processes, evaluates the
feasible treatment processes, and estimates the quality of the wastewater
from the treatment processes. Non-water quality environmental impacts, e.g.,
noise and air, of the feasible treatment processes are then reviewed along
with the economic impacts, financial impacts, the age of equipment and facil-
ities involved, the industrial process employed, the engineering aspects of
the various types of control techniques, and the space required.
After all of the information is considered, EPA determines which pollu-
tants to include in the standard and the concentration of those pollutants.
The categorical pretreatment standards represent, therefore, the prohibition
on the discharge of pollutants that EPA determines can be economically
achieved by industry considering other impacts. As previously mentioned,
those standards are not based on water quality considerations.
The economic impact of the categorical pretreatment standards is a major
concern to EPA. Therefore, the feasible treatment options identified in a
development document are evaluated both economically and from a financial
viewpoint.
In the economic analysis, two cost components are considered. The first
is the capital cost or the intitial investment required to install pollution
control technology. Capital costs include the cost of planning, designing,
and installing the pollution control technology.
The second cost component is the total annual cost of compliance with
the standards. The annual cost includes operation and maintenance (O&M)
costs of the control technology, e.g. energy costs and sludge disposal costs,
and the principal and interest payments on the intitial investment.
Both capital and annual operation and maintenance costs are used to
evaluate the economic impact of a control technology. In addition, the fi-
nancial impact of that technology is considered. The investment requirements
for compliance and associated annual costs are compared with balance sheet
and income statement information to determine the projected financial status
of the plants after all compliance requirements are met. If a plant's
19
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estimated profitability after compliance is negative or if the projected debt
retirement burden after investment is too high to be paid out of the annual
cash flow, that plant is considered a candidate for closure because of the
standard.
As previously indicated, information obtained from the economic and fi-
nancial analyses is reviewed along with other available information before
categorical pretreatment samples are promulgated. Management at EPA then
determines which pollutants to regulate and the concentration of those
pollutants.
CATEGORICAL PRETREATMENT STANDARDS - EXAMPLE
As of this date, categorical pretreatment standards have been promul-
gated for the electroplating category and proposed for leather tanning, tex-
tiles, timber, gum and wood, petroleum and refining, and paint and ink cate-
gories. This section illustrates the procedure used to develop categorical
pretreatment standards by reviewing the electroplating pretreatment standards.
The development document for the electroplating pretreatment standards
indicates that the electroplating industry is a major contributor of toxic
pollutants to POTWs. There are approximately 9,400 plants in the industry,
most of which are concentrated in heavily industrial areas. Approximately
6,600 of those plants are indirect dischargers and discharge approximately
one billion gallons of process wastewater per day to POTWs. The industry's
significant pollutants include: chromium, copper, nickel, zinc, cadmium,
lead, aluminum, various precious metals, cyanide, and organic compounds.
Those pollutants occur in concentrations sometimes exceeding 100 milligrams
per liter.
Table 1 contains the categorical pretreatment standards for the precious
metals subcategory of the electroplating industry. Different limitations
were established for plants that discharge less than 38,000 liters per day
than for plants that discharge 38,000 liters or more per day because results
of the economic analysis indicated that regulations would most severely im-
pact the industry's low-discharge plants. EPA estimated that compliance with
the regulation would cause 737 plants to close, 600 of them small plants in
the job shop sector. By using a 38,000 liter/day flow cut-off, EPA minimized
the impact of the regulations while still making significant environmental
improvements.
Table 2 contains the option considered in settling the 38,000 liter/day
flow cut-off. As shown in the table, the closure rate is not very sensitive
to flow cut-off, but the percentage of untreated flow is. For example, be-
tween a flow cut-off of 38,000 liters/day and 61,000 liters/day, the closure
rate decreases only by 1.3 percent, but the percentage of untreated flow
doubles from three to six percent. Higher flow cut-off levels follow the
same pattern of rapid increase in untreated flow and small decreases in
closure rates.
Setting the cut-off level at 38,000 liters/day reduces the closure rate
by over five percent while allowing only three percent of the flow to not be
20
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TABLE 1 PRETREATMENT STANDARDS FOR PRECIOUS METALS SUBCATEGORY OF
Sources
Pollutant or
Pollutant Property
CN,A (cyanide)
Pb (lead)
Cd (cadmium)
Sources
Pollutant or
Pollutant Property
Ag (silver)
CN,T (cyanide)
Cu (copper)
Ni (nickel)
Cr (chromium)
Zn (zinc)
Pb (lead)
Cd ( cadmium)
Total Metals
Discharging Less than 38,000
Maximum for
Any One Day (mg/1)
5.0
0.6
1.2
Discharging 38,000 Liters or
Maximum for
Any One Day (mg/1)
1.2
1.9
4.5
4.1
7.0
4.2
0.6
1.2
10.5
Liters /Day
Average of Daily
Values for 30
Consecutive Days (mg/1)
1.5
0.3
0.5
More /Day*
Average of Daily
Value for 4 Consecutive
Monitoring Days (mg/1)
0.7
1.0
2.7
2.6
4.0
2.6
0.4
0.7
6.8
* Revised per stipulation.
TABLE 2 FLOW CUT-OFF
OPTIONS FOR ELECTROPLATING INDUSTRY
Flow
Cut-Off
Closure
Gallons/Day (liters/day) Rate (%)
None
10,000 (38,000)
16,000 (61,000)
20,000 (76,000)
30,000 (114,000)
40,000 (152,000)
25.6
20.5
19.2
18.3
17.5
17.5
Untreated
Flow (%)
0
3
6
8
13
20
21
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treated. EPA believes the closure rate can be reduced even further if small
shops in the job shop sector use financial assistance available from the
Small Business Administration to finance the needed controls.
In addition to establishing the flow cut-off at 38,000 liters/day, EPA
also decided to only regulate cyanide, lead, and cadmium for the low flow
shops. Lead and cadmium were regulated because they pose significant human
health problems, while cyanide is extremely toxic. These three pollutants
have a greater potential to damage the environment than the other pollutants
do.
The electroplating categorical pretreatment standards were based on the
following control technologies: cyanide oxidation, chrome reduction, pre-
cipitation of metals by means of pH adjustment, and solids removal. Many of
the industries in the electroplating category already use some of these
technologies.
This example illustrates the information collected when developing cate-
gorical pretreatment standards and how it is used to establish those stan-
dards. The final discussion on the pollutants regulated and the concentra-
tion of those pollutants is made by the management at EPA.
POTW TOXIC POLLUTANT STUDY
In 1978, EPA initiated a study on toxic pollutants in POTWs. The pur-
pose of that study is to determine the fate of toxic pollutants in POTWs.
Influent, effluent, and sludge samples are being collected at 40 POTWs and
are being analyzed for the 129 priority pollutants.
Several factors are considered when selecting a POTW for sampling as
part of this study. They include:
treatment processes
- size
amount of industrial flow
type of industrial flow
- POTW operating efficiency
flow as percent of design capacity
- POTW location.
POTWs selected to date represent the full spectrum of common treatment
processes in use today. The biological treatment process in most of those
plants is either activated sludge or trickling filter since those processes
are most prevalent.
POTW size is measured by design flow. Since the Part 403 General Pre-
treatment Regulations pertain to POTWs with a capacity of 5 MGD and greater,
all of the plants samples in this study are 5 MGD or greater in size. The
existing flow at the POTW also had to be 50 percent or higher of the design
flow.
22
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If possible, only POTWs that meet the secondary treatment regulations
were selected for sampling. Since few plants meet those requirements all
the time, POTWs with reasonably good operation, as determined by the EPA
project officer, are being sampled.
The POTWs sampled in this study have an industry flow from zero to more
than 50 percent. We anticipate that all of the 37 industrial categories for
which standards are being promulgated by EPA discharge to one or more of the
POTWs.
Currently, 27 POTWs have been sampled across the country. Results of
the wastewater analyses for 21 of the POTWs have been received and are being
evaluated. Results of the sludge analysis for nine of the POTWs are also
being evaluated. We expect to publish an interim report with data from 20
of the 40 POTWs by October of this year.
There are currently three options for the use of the data obtained from
this study. The first is that the data could be used to either support or
not support the categorical pretreatment standards. These data could also
be used to support regulations on sludge management. That could also impact
the categorical pretreatment standards since those standards may be related
to the requirements established for sludge management.
The third option for the use of the data from this study is to support
best practicable waste treatment technology (BPWTT) standards for POTWs.
Data could be used to determine which pollutants to regulate and to determine
the effluent concentrations for those pollutants.
23
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PB83-142174
MINIMIZING COSTS BY GOOD FINANCIAL MANAGEMENT
S. Sacks
Synthetic Organic Chemical Manufacturers Association, Inc.
1612 K Street, N.W., Suite 308, Washington, DC 20006
ABSTRACT
There are a number of Federal financial programs that can be used to
minimize the cost of pollution control facilities. The Small Business Ad-
ministration has an Economic Injury Loan Program for pollution control cover-
ing requirements for air, water, RCRA, and TSCA as well as other Federal
regulations. The direct loans are currently being offered at 8 1/4% and
may extend up to thirty years. An alternative, Pollution Control Revenue
Bond Program guaranteed by the Small Business Administration can save a com-
pany roughly 25% of their financing costs over a period of 25 years over
conventional financing plans. The bonds are tax-exempt and guaranteed by
the full faith and credit of the U.S. Government. The program is open to
the smaller companies that are at a competitive disadvantage with the larger
companies. The bond program should be considered for companies seeking
sums over $150,000. Companies may also take advantage of tax incentives
and tax credits such as the rapid tax amortization program and the Tax
Reform Act of 1978.
TEXT
With the prime interest rate at the highest level ever in the history
of the country and the inflation rate close to 20%, financing pollution
control costs is an extremely difficult task.
For this reason, I want to discuss various important financial assis-
tance programs that you should keep in mind when advising a client about a
treatment plant, or helping an industry come into compliance with your
local, state and Federal laws or installing a plant.
There are certain tax considerations in regard to pollution control
devices from certain sales, use and property taxes that allow industries to
pay lower taxes when purchasing pollution control equipment.
Businesses installing pollution control equipment currently may choose
between two methods of income tax treatment. Under the first alternative,
the corporation chooses to depreciate the pollution control equipment,
using any IRS-approved depreciation method. In addition, as a result of
the 1978 Tax Reform Act, the company is allowed to take an investment tax
credit of 10%, but the credit may not exceed total tax liability, or
-------
$25,000 plus 50% of the tax liability in excess of $25,000, whichever !•-'
less. Should the allowable amount result in unused credit, this excesp ™*y
be carried back to the three preceding tax years, and the balance still un
used in those years may be carried over to the 7 succeeding tax years. 10
qualify for the full investment credit, the property or equipment acquired
must be depreciable, have a minimum three-year useful life, to be a tangible,
integral part of the enterprise's operations, and be placed in operation
during the year for which the credit is sought. Structures built to house a
Useful Life Percent of Cost of
Property Qualifying for Credit
Under 3 years 0
3 years, or more but less than 7 years 33 1/3
5 years, or more but less than 7 years 66 2/3
7 years or more 100
necessary component or which are part of a component qualify for credit,
although a structure built to provide shelter alone ordinarily does not
qualify for credit. Related mechanical equipment also is eligible even if
located physically aprat from the business seeking the tax credit. Under
the second alternative tax treatment, the firm may elect to take advantage
of the special rapid Amortization of Pollution Control Facilities through
Section 169 of the Internal Revenue code. The provision was introduced in
1969 to encourage private enterprise to cooperate in efforts to cope with
the problems of industrial pollution. As of the Tax Reform of 1978 rapid
amortization applies only to plants in operation prior to January 1, 1976,
whose facilities were acquired or installed after 12/31/75. Rapid amortiza-
tion is attractive only at very high discount rates or high inflation rate
or in cases where the equipment would otherwise have a useful life greater
than twelve years. The 10% tax credit may be taken regardless of whether
rapid amortization is used. However, if industrial revenue bonds are used
along with rapid amortization, then only a 5% tax credit is allowable.
Presently Congress is considering a rapid amortization write-off in three
years.
Aside from the tax angles for pollution control, there are various
Federal financing assistance programs to half ease the cost of pollution
control. The Pollution Control Loan Porgram was provided for in Section 8
of the FWPCA Amendments of 1972 (92-500) entitled "Loans to Small Business
Concerns for Water Pollution Control Facilities" and authorizes loans to
assist small businesses in adding to or altering their equipment, facilities
or methods of operation in order to meet the Water Pollution Control re-
quirements established under the FWPCA. EPA must certify to SBA that the
equipment is necessary and adequate to meet their pollution control re-
quirement .
The loan program comes under the SBA Economic Injury Loan Program and
during the past fiscal year 100 million dollars was appropriated for the
direct loans. Incidentally, only 40 million dollars of this amount was used.
25
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An "economic injury loan" is a loan based on a hardship caused the
business as a result of government regulation, namely pollution control re-
quirements, etc. The economic injury loan program is now made up of water
and air pollution control requirements, coal mine, health and safety,
occupational safety and health, emergency energy shortage loans, consumer
protection loans, and now includes the Toxic Substances Control Act and the
Resource Conservation and Recovery Act requirements.
To date the SBA has lent roughly sixty million dollars with the average
loan being $125,000. Thus far the largest number of loans has been to elec-
troplaters, with the wood and paper industry second, and food canning third.
The direct interest rate is 8 1/4% and may extend for up to thirty years.
Loans are made to concerns who are likely to suffer an economic injury with-
out them: Loans have ranged from $5,000 to 4 million. (In cities with over
200,000 people, two turndowns from a bank are required.)
The loan turndown, however, may take any of a number of forms. The
interest rate may be too high, the bank may require a very short payback
period or the bank may require more collateral than can be met by the
applicant. The bank may not want to lend that much money for a nonproductive
venture.
There are participation loans and guaranteed loans with SBA and commer-
cial lending institutions, but these rates are considerably higher (partici-
pation rate is 1% below the guaranteed rate and the guaranteed rate is 1/2%
over the prime rate. Today the prime rate is 19% and so you're looking
at 20% money.
The loan program is on a first come first served basis and SBA has
tried to improve its image and cut down on paper work. Every SBA office is
being made aware of the environmental problems of certain industries.
ELIGIBILITY AND PURPOSE OF LOAN
1. The business has an effluent discharge requiring an NPDES permit. The
permit is in essence a contract between a discharger and the government.
It regulates what may be discharged and how much. It sets specific
limits on the effluent from each source. With a schedule of cutting
down on the effluent with a view towards total elimination.
2. The business emits discharges through a sewer line into a (307) pub-
licly owned treatment works, and the city or town requires pretreatment
of waste discharge, (the applicant must submit the municipal permit
number and receive from the municipal POTW a statement detailing the
specific pretreatment requirements) .
3. The business plans to discharge into a municipal sewer (307) system
through the construction of a lateral or interceptor sewer.
4. The business is subject to the requirements of a State or regional
authority for controlling the disposal of pollutants that might affect
groundwater (208 requirements).
26
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5. The business is subject to a Corps of Engineers permit for disposal ot
dredged or fill material (404) from anyone proposing to discharge
dredged or fill material into navigable waters of U.S.
6. The business is subject to Coast Guard or State requirements (312) re-
garding the standard of performance of marine sanitation devices
controlling sewage from vessels. All regulated vessels will be re-
quired to install a certified device or otherwise meet EPA standards
by January 30, 1970.
7. The business is implementing a plan to control or prevent the dis-
charge or spill of oil or other hazardous substances. (Stores oil
greater than 1320 gallons above ground and 42,000 below.) (Section
311J of P.L 92-500)
Basically any requirement that is in compliance with Federal Pollution
Control Requirements is eligible for the loan program. Air pollution con-
trol, toxic substances requirements and solid waste requirements are also
eligible.
For purposes of the Small Business Administration, a small business
is defined either by the number of employees or sales volume. A business
having less than 250 employees is definitely small business. Certain in-
dustries can be considered small even though they have as many as 1,500
employees.
Aside from the SBA Economic Injury Loan Program, the Economic Develop-
ment Administration also has a good loan program for pollution control.
The consideration under the EDA program is based on the number of jobs
created or saved and whether or not the business is located in an economi-
cally depressed area. An advantage of EDA program is that a business need
not be considered small. Businesses may also set up a cooperative arrange-
ment for handling the pollution control costs. Currently, the interest
rate for EDA loans is 11%.
The Farmers Home Administration also has an attractive loan program
that should be consulted in rural areas.
Lastly. I want to tell you about a form of financing which is relative-
ly new and at present the most attractive vehicle for financing pollution
control costs.
Public Law 94-305 authorized SBA to guarantee the payments under quali-
fied contracts entered into by existing small business concerns, which are,
or are likely to be, at an operational or financing disadvantage with other
businesses for the purpose of acquiring pollution control facilities. In
other words, the SBA guarantees the payment of 100% of the aggregate to be
financed. The act allows the loans to be financed from proceeds of tax-
exempt bonds. These bonds thus are rated AAA, and the borrower is able to
borrow money at roughly 25% less than a nonrated bond. On a $200,000 issue,
it amounts to a savings of $50,000 over the 25-year term.
27
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The purpose of using tax-exempt industrial revenue bond financing for
pollution control facilities is to obtain the most advantageous interest
rate and repayment terms possible.
In order to qualify for the program, the SBA requires that the appli-
cant must be one which together with its affiliates is independently owned
and operated, is not dominant in its field of operation and does not have
a net worth in excess of $6 million, and does not have an average net in-
come, after Federal income taxes, for the preceding two years in excess of
$2 million and qualifies as a small business concern under section 121.3-10.
The small business concern must be at an operational financing dis-
advantage with other businesses with respect to the planning, design or
installation of pollution control facilities. The applicant small business
concern must be in business a minimum of five years, and have a history
of profitable operations for any three of the last five years. The small
business concern must provide evidence from a Federal, State, or local
environmental regulatory authority that the facility is likely to help
prevent, reduce, abate or control pollution or contamination.
The repayment period is usually twenty five years. The principal
amount to be financed under a qualified contract cannot exceed $5,000,000.
A small business initially requests a loan from a state or local
authority empowered to issue the bonds. In most states it is the state
economic development agency or business development agency. In other areas
bonds are issued directly by municipalities.
The authority, in turn, requests that the SBA guarantee the loan. The
SBA, after reviewing the applicant's business qualifications under the
program guidelines, agrees to guarantee the loan and reports to the
authority. When the authority has several businesses with the SBA approval,
it can package a bond issue of marketable size. The issue is marketed
through an underwriter, and the proceeds from the issue are made to the
businesses.
The loan funds are deposited with an appointed trustee. The business-
man can use the proceeds over a three-year period, to finance construction
and equipment required to meet environmental control standards, costs of
site preparation, and all expenses necessary to begin and supervise con-
struction, including legal and engineering costs. These funds may also
be used to pay bond issuance expenses, application fees, establish a re-
serve fund, and refinance existing debt for a pollution control facility.
They may not be used to replenish working capital. Funds are dispersed
by the trustee upon receipt of invoices for any of the approved uses.
Additional Requirements
The small business concern is required to submit the following information
with its application:
1. SBA Form 912, "Statement of Personal History," on all officers,
director, holders of 20 percent or more of the voting stock;
28
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all partners and proprietor of the applicant small business.
(This form can be obtained by any local SBA office.)
2. Annual financial statements for the preceding five (5) fiscal
years. (Audited statements for the most recent year, or for all
5 years may be required by SBA.)
a. Standards for Audited and Unaudited Financial Statements
Financial statements include three basic statements -
balance sheet, income statement, and statement of change
in financial position. The statements are to be prepared
in accordance with generally accepted accounting princi-
ples adopted by the Financial Accounting Standards Board
(FASB), and have adequate footnote disclosure so as to
make the statements not misleading.
When audited statements are required, such audits are to
be made by an independent auditor in accordance with
generally accepted accounting standards.
3. Interim financial statement (not older than 90 days).
4. Two years pro forma cash flow after giving effect to the
financing applied for.
5. Most recent financial statements on all affiliates listed in
item No. 4 of the application.
6. A brief history of the applicant small business, including
type of business, method of operation, data established,
ownership composition, and background experience of key
management personnel.
7. Copy of the appraisal of the value of other collateral
(if required) tendered as additional security for the
financing (including the existence and amount of out-
standing liens thereon).
8. Copy of bid proposals or estimates including plans and
specifications for the pollution equipment or property,
construction/installation, etc.
9. An in-furtherence certificate from the appropriate environ-
mental regulatory authority stating essentially that the
pollution control facility, when completed in accordance
with the plans and specifications, will help prevent, reduce,
abate, control noise, air, or water pollution or contamination
by removing, altering, disposing or storing pollutants, con-
taminants, wastes, or heat, or property used for the collection,
storage, treatment, utilization, processing, or final disposal
of solid or liquid waste.
29
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10. An opinion from the consulting engineer/architect responsible
for the design of the facility, that the facility, when com-
pleted, will meet the required pollution control standards or
regulations.
While not specifically required from each applicant, sound
judgment dictates that:
a. On a case-by-case basis, SBA may require third party
guarantees and/or additional (other than the pollution
facility) tangible security, and
b. When outside contractors are used for construction and/or
installation of the facility the applicant may wish to
consider the advantages of a surety bond.
The Qualified Sponsor:
Because of its close financial relationship to the applicant, the qualified
sponsor will usually be the bank of account of the small business concern.
In addition to completing Part II of the application (SBA For 1136) and
assisting the small business concern prepare its part of the application
for SBA assistance, the sponsor is asked to prepare a complete financial
and credit analysis of the small business concern (including affiliates)
and to issue an opinion and recommendation as to the applicant's credit-
worthiness for the financing in accordance with its and SBA's established
credit criteria and requirements (section D, below). This opinion, analysis
and recommendation is made with no liability on the part of the sponsor.
(See Appendix I) While SBA relies upon the analysis and recommendation,
final determination whether or not to issue its guarantee rests with SBA.
The demand for this type of financing is extremely high. In 1979
industry spent 7 billion dollars in capital expenditures for pollution
control facilities with half of that figure being financed with IDBs. I
am sure in 1980 the demand for pollution control facilities will continue.
With credit as tight as it is, and the cost of money at an all time
high, it is almost the only alternative left for financing pollution
control facilities. Hopefully the rate which was 6 1/4% in August, 7 1/2%
in December, 9% in February and 9.2% in March will start to come down, but
your guess is as good as mine.
For financing pollution control facilities the two best methods are
the pollution control revenue bonds guaranteed by the Federal government
and the pollution control loan program.
30
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PB83-142182
COMPATIBILITY ASSESSMENT OF
'MUNICIPAL/INDUSTRIAL WASTEWATERS FOR
COMBINED BIOLOGICAL TREATMENT*
by
A. W. Busch
Environmental Engineering Consultant
7223 Lavendale Circle
Dallas, Texas 75230
ABSTRACT
There are numerous chemical and hydraulic aspects of biological treat-
ment of combined municipal and industrial wastewaters. Compatibility is
effected by qualitative and quantitative characteristics of the wastes
involved. Assessment should include reaction rates, phase distribution of
organics, concentration effects, hydrographs and relative volumes, trans-
port time effects and nature of sludges produced. When compatibility
assessment is properly done during process design, combined treatment is
frequently not the best alternative. Because of legislation and regulations
developed since 1970, combined biological treatment is less attractive now
than ever. Separate treatment is increasingly the obvious method of choice-
where a choice can be made.
INTRODUCTION
Combined treatment of municipal and industrial waste waters is
largely a post World War II issue. In fact, the first 20-year index (1928-
48) of what is now the Journal of the Water Pollution Control Federation
lists no articles under combined or joint treatment. The next 10-year
index (1949-58) shows 58 listings under "combined disposal."
These numbers indicate that combined treatment became a "high-ground"
or "motherhood" position in engineering practice, plus, of course, reflect-
ing the real-world fact of urban industrial locations. Many smaller towns
and cities actively solicited industrial siting by offering combined treat-
ment as an inducement. Clearly, the ground rules have changed since 1970.
^Presented at Conference on Combined Municipal/Industrial Wastewater Treat-
ment, University of Texas at Dallas, Richardson, Texas, March 25-27, 1980
31
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i
o
5 >
UJ <
o: a
UJ CO
\- en
en Q
CD CD
CD -Q
U_ \
o:
4 —
3 —
FIG. 1
SYNTHETIC RUBBER WASTE
FOOD PROCESSING WASTE
PLASTICS WASTE
ACRYLATE WASTE
100 200 300 400 500
SOLUBLE TbO.D. CONCENTRATION , mg/l .
UNIT RATES OF SUBSTRATE REMOVAL
FOR VARIOUS INDUSTRIAL WASTES
SHOWING LINEAR PORTION OF CURVES2
32
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Perhaps the best indication that combined treatment is not a panacea
and in fact, may be an undesirable approach, is that EPA personnel spent
6 years in developing and promulgating General Pretreatment Regulations [U
as required by PL 92-500 in October, 1972. EPA has, of course, labored
under a succession of increasingly stringent environmental laws addressing
toxic and hazardous pollutants which had to be accommodated by pretreatment
regulations. Nonetheless, it is disappointing to find BOD listed, as a
"material" when, in fact, BOD represents only a parameter of variab-le and
even questionable significance in process and system design [2J.
COMPATIBILITY
In setting out pretreatment requirements for industrial wastes dis-
charged to a publicly owned treatment works (POT¥), EPA was required to
address incompatibility effects [1]. EPA chose to use conventional biologi-
cal treatment systems designed to achieve secondary treatment effluent
standards as the basis for assessing incompatibility effects. EPA further
extended its assessment to include ultimate fate of contaminants, especially
toxic pollutants, in sludge disposal and air pollution questions.
This approach infers that there are few POTWfs receiving industrial
wastes which were designed for the combined wastes and this may be correct.
However, subsequent papers at this conference seem to offer case histories
of recent designs based on combined treatment.
This paper is intended to set out some of the factors pertinent to
compatibility assessment of combined wastes as a basis for process and
system design. Factors addressed herein are reaction rates, phase dis-
tribution of organics, concentration effects, hydrographs and relative
volumes, transport time effects and nature of sludges produced.
REACTION RATES
Reaction rate differences for various components of combined wastes
represent a major factor in design economy. Because all wastes must be
detained long enough for the slowest component to react, combined systems
are almost inevitably larger than separate plants would be in aggregate.
Figure 1 shows typical rates for several industrial wastes. A mixture
would be controlled by the slowest rate. Therefore, a first step in
compatibility assessment should be definition of reaction rate character-
istics.
PHASE DISTRIBUTION OF ORGANICS
Biological treatment is needed only for the bacterial conversion of
dissolved organics to cells, carbon dioxide and water. (Other intermediate
or end products are possible.) Many municipal wastes contain little dis-
solved organics after spending hours or days in a self-seeded tubular re-
actor called a sewer. Figure 2 shows that in many cases only effective
solids separation is required to meet secondary effluent standards.
Numerous, possibly the majority of, biological treatment plants receiving
33
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400
300
o»
E
•»
m
Q
O
CD
200
100
I I r
I I I I | I r I i
0 0
8
• INFLUENT
O PRIMARY EFFLUENT
D BIOLOGICAL
EFFLUENT
I I I I I I !_ l
100 200 300
SUSPENDED SOLIDS, mg/l.
400
FIG. 2 B.O.D5 AND SUSPENDED SOLIDS DATA FOR
MUNICPAL WASTE WATER FROM TEN
ANNUAL REPORTS OF SEPARATE PLANTS1
34
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only, or predominately, municipal wastewaters serve only to make anaerobic
influent aerobic and to solubilize particulate organics for subsequent
(partial or complete) bacterial conversion.
Figure 3 shows a conceptual treatment scheme, using established
technology components, for municipal wastes or combined wastes low in dis^-
solved organics when entering the treatment system. This is not applicable
for combined wastes high in dissolved organics.
CONCENTRATION EFFECTS
Concentration effects are well addressed in EPA's pretreatment regula-
tions and have been the subject of numerous articles in our literature.
Most concern is directed at toxic substances or ions, whether biodegrad-
able or not. In fact, Figures 4 and 5 show that bacterial systems have
a potential for assessing concentration effects in terms of toxicity [3].
Mass culture processes such as activated sludge have a capacity for
removing certain species of toxic ions, such as metals, and can intentional-
ly be used for this purpose, provided sludge disposition can accommodate
the presence of toxic ions. Whereas separate industrial wastewater treat-
ment systems can often be managed from this perspective, combined waste-
waters produce much more sludge of a different nature and are not as
amenable to use of this unique capacity. This is addressed further under
the subject of nature of sludges.
HYDROGRAPHS AND RELATIVE VOLUMES
Two truisms exist here: (1) average flow never exists without
equalization and (2) equalization is greatly underutilized in municipal
or combined municipal industrial treatment.
Figure 6 shows a few of the infinite hydrographs all producing the same
calculated average rate of flow and/or load. Figures 7, 8 and 9 show how
municipal flows could be equalized for application in the Figure 3 flowsheet,
Conventionally, of course, equalization of sorts is provided by sizing
treatment components for peak flow rates. This is expensive, limits
innovation and is really the reason for the various "efficiencies" estab-
lished for treatment processes although reflecting only system design
deficiency [2].
A further aspect of hydrographs for industrial wastes in combined
treatment is that they may not be continuous, and thus critical organic
components may be only intermittently available to maintain micro-
organisms needed for their conversion.
Obviously, relative volumes of municipal and industrial wastes may
range from a preponderance of one in large cities to the other in a
single industry, small town. This factor can be overriding in process and
system design.
35
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VARIABLE.
FLOW
AERATED
VARIABLE
VOLUME -
SOLUBLE
ORGANIC
REMOVAL
UNIFORM
FLOW
COO r-
HYORATION L
MASSIVE
RECYCLE
CoO + ASH
EXHAUST
GAS
SOLIDS CONTACT
UNIT FOR
CLARIFICATION,
SOFTENING,
PO^ REMOVAL,
DISINFECTION
pH
CARBONATION
FOR pH
ADJUSTMENT 8
NH3 STRIPPING
SOLIDS
C02 + CO
DEWATERING:
ORGANICS +
CaC03 +CoPO4
Mg(OH)2
EFFLUENT
CALCINING
SOLIDS
FIG. 3 SCHEMATIC OF MUNICIPAL WASTE WATER TREATMENT BY
AERATION ,LIME SOFTENING, STRIPPING AND CARBONATION^
-------
GLUCOSE SUBSTRATE
FIG. H
ISO'
TIME-HOURS
200
25O
30O
EFFECT OF INCREASING COPPER CONCENTRATION ON
OXYGEN UPTAKE WITH TIME FOR GLUCOSE IN THE
BOTTLE SYSTEM (de Bruin , 19662)
37
-------
Co
00
o>
O
O
CD
LU
O
X
o
2 -
I -
O
KCN
7.5 xlCT5
mol/l.
3.6 mg/l
KCN
mo-4
mol/l.
4.7 mg/l
FIG. 5
8O
90
100
40 5O 6O
TIME-HOURS
OXYGEN UPTAKE VS. TIME FOR INCREASING KCN FOR ONE SEED
CONCENTRATION IN THE BOTTLE SYSTEM
(Zintgroff and Ward, 19692 )
-------
\7nnrnrn 7 rn ~rrn
o
<
cc
f-
2
UJ *
o
z
o
o
x
Ul
h-
<
ac
$
o
'UJJU./2JULJUULJLA
0
18
21
36 9 12 15
HOUR OF THE DAY
FIG. 6-COMPARISON OF DIURNAL FLOW-CONCEN-
TRATION PRODUCTS TO AVERAGE VALUE
24
39
-------
3
LJ
O
<
cc
LU
<
u.
O
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1.0
0.9
| 0.8
2 0.6
o
_)
U.
UJ
D
O
BASIN VOLUME REQUIRED:
FOR UNIFORM FLOW.
111,000 GAL/M.G.
FOR AVERAGE FLOW OR LESS
46,000 GAL/M.G.
MAXIMUM
STORAGE
REQUIRED
46,000 GAL./M.G.
0.5
0.4
0.3
0.2
O.I
MAXIMUM STORAGE
REQUIRED 65,000 GAL/M.G.
I2M 2
10 12 N 2
TIME
10 12 M
FIG. 8
MASS DIAGRAM FOR TYPICAL DIURNAL FLOW OF
MUNICIPAL WASTE WATER SHOWING VOLUME OF
AERATED EQUALIZATION BASIN REQUIRED TO
ACHIEVE UNIFORM DISCHARGE TO SUBSEQUENT
TREATMENT 2
41
-------
MAX. DEPTH
UNTREATED
WASTE WATER
MIN. DEPTH
i i
Lllfdb
TO SOLIDS
SEPARATION
FIG. 9
SCHEMATIC OF VARIABLE VOLUME AERATED
EQUALIZATION BASIN FOR MORE UNIFORM
FLOW TO MUNICIPAL WASTE WATER TREATMENT
SYSTEM 2
-------
TRANSPORT TIME EFFECTS
As noted earlier, sewers are self-seeded tubular reactors for municipal
wastes and for some industrial wastes such as food processing, in particular.
Generally as treatment facilities become larger, as is often the case tor
combined treatment, transport times become longer. The impact of transport
time on wastewater characteristics can be significant. For easily degraded
wastes, such as food processing, oxygen demand can be increased in^both
rate of exertion and in total amount by anaerobic transport conditions.
Inorganic components such as nitrates and sulfates are reduced and must be
re-oxidized in the treatment process.
An added dimension of transport time which must be evaluated is
infiltration. Some of the early combined treatment collection systems
proposed in the Houston area included truly phenomenal infiltration
allowances.
NATURE OF SLUDGES PRODUCED
The widest range of differences in sludges is found between waste-
activated sludge from treatment of soluble organic industrial wastes and
a mixture of primary and waste-activated sludge from municipal wastes,
both in nature and amount.
Industrial waste-activated sludge is stable and can be conveniently
placed in deep anaerobic/aerobic ponds or tanks because of the slow rate
of release of reduced decomposition products [2], The concept of aerobic
digestion (with, say, 10 days detention) is not applicable to such indus-
trial waste-activated sludges from systems with solids residence times of
10 to 50 days. However, this can be considered as a reservoir of acclimated
organisms available in the event of a process breakdown.
In contrast, mixed municipal sludges are highly putrescible, contain-
ing a large fraction of organic matter other than micro-organisms. Aerobic
decomposition will continue at significant rates if aerobic digestion is
provided. Anaerobic decomposition will usually be too vigorous to use
anerobic/aerobic ponds or tanks without scum and odor problems.
SUMMARY AND CONCLUSIONS
EPA's difficulties with defining incompatibility effects of combined
biological treatment are due to complex legislative requirements, aggravated,
at least to some extent, by lact of compatibility assessment during design,
especially prior to 1972.
Generally speaking, the concept of combined biological treatment is
less attractive now than ever. While individual cases can be cited where
mutual advantages can be, and have been, shown, separate treatment ia in-
creasingly the obvious method of choice where a choice can be made.
43
-------
REFERENCES CITED
1. General Pretreatment Regulations for Existing and New Sources of
Pollution, Federal Register, Monday, June 26, 1978, Part IV.
2. Busch, A. W. , Aerobic Biological Treatment of Wastewaters—Principles
and Practice, Gulf Publishing Company, P. 0. Box 2608, Houston, Texas
77001, 1971.
3. Busch, A. W., "A Bioassay Technique for Relative Toxicity in Water
Pollution Control," presented at the 51st Annual Conference, Water
Pollution Control Federation, October, 1978, Anaheim, California.
44
-------
PB83-1«*2190
BIOLOGICAL INHIBITION SCREENING OF
INDUSTRIAL WASTEWATERS
E. L. Stover Ph.D., P.E.
Metcalf & Eddy, Inc.
Boston, Massachusetts 02114
ABSTRACT
Feasibility investigations for assessment of the biological treatability
of industrial wastewaters should initially include a program for character-
ization of the wastewaters with respect to expected flows and loads. Histor-
ical data should be reviewed when available, and routine chemical analyses
as well as some specialized analyses should be conducted. The specialized
analyses should center around possible inhibition or toxicity problems.
Quantitative assessment of inorganic and organic compounds possibly causing
inhibition problems by atomic absorption and gas chromatograph-mass spectro-
photometer analyses is a time consuming and expensive proposition. A simpler
method of inhibition screening in terms of required analyses time and expense
would be to conduct bioassay type procedures. A simple and inexpensive
microbiological inhibition screening test procedure can be conducted by
treatment plant personnel at municipal plants receiving industrial wastewater
discharges to provide estimates of the threshold inhibition levels to both
the carbonaceous and nitrification reactions. This procedure consists of
adding different dilutions of wastewater to a series of BOD bottles contain-
ing the appropriate seed source (carbonaceous or nitrifying) and monitoring
the respective respiration rates. The factors affecting this inhibition
screening procedure and important experimental design considerations are
presented along with results from inhibition testing of various industrial
wastewaters for both carbonaceous removal and nitrification. This test pro-
cedure can be employed to provide valuable screening information relative to
biological treatment, as well as providing monitoring for problem assessment
and changes in the daily operations of treatment facilities.
INTRODUCTION
The possible presence of inhibitory or toxic compounds to biological
treatment processes warrant concern where significant quantities of indus-
trial wastewaters are discharged into municipal systems. Wastewater dis-
charged by industries may be quite different from municipal wastewater, and
extreme care must be taken to ensure that these wastewaters do not impede or
prevent proper operation of the treatment processes. The presence of indus-
trial wastewaters make the behavior of the treatment processes less
45
-------
predictable and may necessitate the selection of completely different pro-
cesses to ensure adequate treatment. Both the flow and loading character-
istics may differ significantly, and slug discharges become a potential
problem. These effects become more significant as the total proportion of
industrial wastewater increases. Industrial wastewaters are subject to
change with process modifications and production of new and different types
of products. Rigid controls may result in the exclusion of contaminants
that are toxic or inhibitory to the treatment processes.
Biological treatment systems, such as activated sludge processes, that
are designed and operated to treat industrial or combined municipal and in-
dustrial wastewaters can receive a variety of inorganic and organic compounds.
Certain types of these compounds, depending on factors of concentration, en-
vironmental conditions and sudden changes in environmental conditions, antag-
onistic effects, and concentration of biomass within the system, are able to
reduce or stop the biological oxidative assimilation rates due to inhibition
or toxicity. Environmental conditions necessary for growth of the nitrifying
bacteria are more specific than those of most of the heterotrophic bacteria
responsible for carbonaceous oxidation. Parameters that require particular
attention are the total applied loadings (food-to-microorganism ratio),
sludge age, or growth rate, temperature, dissolved oxygen concentrations, pH,
and inhibitory or toxic materials.
Certain heavy metals and organic compounds are known to be toxic to
microorganisms, and inhibitory or toxic concentration levels have been
documented in the literature. It has been shown that microorganisms can
adapt to inhibitory substances when they are consistently present at concen-
trations higher than cause toxic effects in slug discharges which can result
in industrial and municipal treatment systems due to dumps, accidental dis-
charges, and stormwater runoff and inflow. The rate and change of magnitude
of environmental conditions can be almost as critical to the biological pro-
cess as toxic materials. Changes in temperature, pH, and dissolved oxygen
levels can cause inhibition and reductions in biological activity.
Chemicals may react with microbial population by a variety of mech-
anisms to cause inhibition of cellular functions and/or destruction of
cellular components vital to cell function. Presence of heavy metals can re-
sult in the occurrence of a variety of abnormalities from deactivation of DNA
and UNA to interference with cell wall synthesis. The gennicidal qualities
of halogen compounds, such as chlorine, have been employed for microbial
disinfection for some time. Certain phenolic derivatives act to disrupt
cell membranes and inhibit oxicase enzymes associated with surface membranes.
Alcohols can cause inhibition of respiration and phosphorylation. Hydrogen
ions in high concentrations can displace essential ionic species, such as
Na+ and CA++, from the adsorption sites on the cell, and hydrolytic reactions
involving hydrogen or hydroxyl ions can produce damage to the microbial cell.
Inhibition of the nitrification process can occur by interference with
the general metabolism of the cell or with the primary oxidative reactions.
Inhibition of primary oxidation reactions can be caused by competitive
effects or metal chelating agents such as thiocyanide, thiourea, and allyl-
thiourea. The general metabolism of the microorganisms can be inhibited by
46
-------
compounds such as quinacrin, rivanol, and quinine. Cytochromes are adverse-
ly affected by cyanide, chlorate, and methyl urethane. Phenol, phenolic com-
pounds, cresol, and halogenated solvents are also potentially toxic materials
to nitrification.
It is not easy to distinguish which type of biological inhibition is
occurring, especially in a wastewater treatment system. What is important
is screening or assessing the potential for and occurrence of inhibition in
the biological wastewater treatment system. Industrial wastewater discharges
should be given special consideration and subjected to screening procedures.
Feasibility investigations for assessment of the biological treatability
of industrial wastewaters should initially include a program for character-
ization of the wastewaters with respect to expected flows and loads. Histor-
ical data should be reviewed when available, and routine chemical analyses
as well as some specialized analyses should be conducted on several waste-
water samples. The specialized analyses should center around possible inhi-
bition or toxicity problems. Quantitative assessment of inorganic and organ-
ic compounds known to cause inhibition problems by atomic absorption and gas
chromatograph-mass spectrophotometer analyses would be a time consuming and
expensive proposition. A simpler method in terms of required analyses time
and expense would be to conduct bioassay type procedures with a population
of appropriate bacteria. This type of procedure would provide a valuable
screening tool, yielding information on the effects of the total wastewater
constituents on biological treatment.
Toxicity has been traditionally measured from lengthy bioassay pro-
cedures by subjecting a reference population of organisms to the substance
in question. Comparison on the basis of such parameters as survival and
metabolic activity are made with a control population of the same reference
organism. Organisms commonly employed for assessment of toxicity of water
pollutants are fish, macroinvertebrates and bacteria.
Methodologies for use of bacterial cultures in aquatic bioassay measure-
ments have not been sufficiently developed due to the difficulty of quantify-
ing an easily measurable response of the bacteria. Biological activity re-
sponses that have received the most attention include oxygen uptake, aden-
osine triphosphate (ATP) and dehydrogenase. Changes in oxygen uptake, ATP
and dehydrogenase activities with concentration of toxic substance have been
documented, but development of successful quantifiable relationships is
difficult. Dissolved oxygen probes, Warburg respirometer and similar
respirometer equipment make this method of activity response measurement
appealing. Measurement of cellular ATP has been found to provide valuable
indication of viable biomass and biomass activity. Biological activity
response has been monitored by the use of 2,3,5-triphenol tetrazolium
chloride as an indicator of dehydrogenase.
Simple and inexpensive microbiological inhibition bioassay type screen-
ing tests employing the oxygen uptake approach can be conducted by treatment
plant personnel to provide estimates of the threshold inhibition levels to
biological treatment of various wastewaters for both carbonaceous and nitri-
fication reactions. This procedure consists of adding different dilutions
47
-------
of the wastewater to a series of BOD bottles containing the appropriate bio-
logical seed source (carbonaceous or nitrifying microorganisms) and monitor-
ing the respective respiration rates. This test procedure does not provide
information relative to the nature of the microbiological inhibition occur-
ring or the specific compound (s) causing inhibition, but it can be employed
to provide valuable screening information relative to biological treatability,
as well as provide a monitoring tool for problem assessment and changes in
the daily operations of treatment facilities. The factors affecting this
inhibition screening procedure and important experimental design considera-
tions along with results from inhibition testing of wastewaters for both car-
bonaceous removal and nitrification are presented.
MATERIALS AND METHODS
The microbiological inhibition testing procedure described by Marks (1)
to detect, under a set of defined conditions in BOD bottles, the threshold
inhibition level for carbonaceous biological oxidation of a compound or
wastewater was modified to provide information on the threshold inhibition
levels of both carbonaceous and nitrogenous oxidation. The threshold inhibi-
tion levels of the compound or wastewater are defined as the lowest concen-
tration of that compound or wastewater that causes a reduction in the car-
bonaceous biological oxidation rate for carbonaceous inhibition and a re-
duction or ceasing of ammonia-nitrogen oxidation for nitrification inhibition,
The information developed from this test procedure can be useful as a guide-
line for determining the effects that a compound or wastewater may have on a
biological wastewater treatment system.
The pH of the wastewater sample to be investigated is first checked and
adjusted if necessary to pH 7.0 to 8.0 to provide a proper environment during
the incubation period. Next a series of dilutions of the wastewater sample
are prepared in BOD bottles, as shown in Table 1. The dilution water is
prepared in accordance with the procedure described in "Standard Methods for
Examination of Water and Wastewater." (2)
During nitrification inhibition screening experiments ammonia-nitrogen
is added to the control bottle to provide a controlled level of dissolved
oxygen depletion that will reduce the dissolved oxygen level in the BOD
bottle by approximately 50 percent of the saturation value of 9.2 mg/1 at
20 C. Ammonia-nitrogen is added to the other BOD bottles as required to
provide excess ammonia-nitrogen above that required for synthesis during
BOD exertion. The ammonia-nitrogen additions should provide around 5 mg/1
of excess nitrogen above that required for synthesis reactions. The amount
to be added can be estimated from historical wastewater characteristics or
by characterizing the wastewater prior to inhibition screening. The bio-
logical culture added to each bottle must contain viable nitrifying micro-
organisms from an existing nitrification facility or developed during pilot
biological treatment investigations.
During carbonaceous inhibition screening experiments six ml of 300 mg/1
glucose stock solution are added to all the BOD bottles instead of ammonia-
nitrogen as indicated in column 5 of Table 1, Biological oxidation level in
48
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TABLE 1. PREPARATION ()K BOD BOTTLES FOR INHIBITION SCREENING (NITRIFICATION)
Bottle
No.
jd)
2
3
1
5
6
7
8
9
10
11
32
Wastewater
volume, ml
0
0
0
1
3
6
10
30
60
100
200
250
.0
.01
.1
.0
.0
.0
.0
.0
.0
.0
.0
.0
Percent
wastewater
volume
0
0
0
0
1
2
3
10
20
33
66
83
.0
.003
.03
.3
.0
.0
.3
.0
.0
.3
.7
.3
Biological
culture
volume, ml
5
5
5
5
5
5
5
5
5
5
5
5
300 mg/L ammonia- Dilution
nitrogen solution water
volume, ml volume
1.0 (3)
(2)
(2)
(2)
(2)
(2)
(2)
(2)
(2)
(2)
(2)
(2)
1. Bottle Mo. 1 = Control.
2. Ammonia-nitrogen added as required to provide an estimated 5 mg/L concentration
available for nitrification.
3. BOD dilution water is added to each bottle as required to fill BOD bottles (total
volume = 300 ml).
-------
the BOD bottles by approximately 50 percent of the saturation value of 9.2
mg/1 at 20 C. The biological seed culture for this experiment should be a
viable heterogeneous culture from an existing treatment facility or developed
from domestic sewage.
The bottles are aerated by connecting the filled bottles to an empty
BOD bottle with a piece of PVC pipe and shaking the two bottles to bring the
dissolved oxygen level close to saturation. The empty BOD bottle can be
filled with oxygen prior to aeration to enhance the aeration process. Fol-
lowing aeration the initial dissolved oxygen levels in each bottle are meas-
ured with a calibrated dissolved oxygen meter and recorded. All BOD bottles
are then incubated in a BOD incubator at 20 C. The dissolved oxygen levels
in each bottle can then be read and recorded daily using the membrane elec-
trode method. The bottles are then reaerated employing the technique pre-
viously described and the resulting dissolved oxygen levels recorded. This
procedure is continued on a daily basis during nitrification screening until
the dissolved oxygen depletion levels out. Nitrate- and nitrite-nitrogen
levels can then be measured in each BOD bottle as required to determine the
degree of nitrification achieved. During carbonaceous screening the bottles
can be read daily or simply incubated for a three day period, at which time
a final dissolved oxygen measurement in each bottle is determined.
If the wastewater under investigation has an immediate dissolved oxygen
demand, this demand should be satisfied prior to adding the wastewater to the
BOD bottles. When the wastewater exerts a chemical oxygen demand that occurs
slowly, it becomes necessary to set up a duplicate test eliminating the bio-
logical culture. The wastewater employed during the duplicate test for de-
termination of chemical oxygen demand should be sterilized to destroy any
oxygen consuming microorganisms present in the wastewater to prevent natural
seeding.
During the BOD bottle inhibition screening procedure, it is impossible
to distinguish between oxygen consumption due to aerobic organotrophic metab-
olism of the carbon sources in the wastewater (carbonaceous BOD) and oxygen
consumption by the aerobic autotrophic microorganisms (nitrification). The
oxygen uptake by the nitrifying bacteria in the BOD test has sometimes been
termed the "second-stage uptake," and exertion of this oxygen demand is
usually not a factor during the five-day incubation period due to low numbers
of nitrifying bacteria and their relatively slow growth rates (3), The in-
fluence of initial organic carbon concentrations, carbon to nitrogen ratios
and growth rates of the carbonaceous microorganisms, as discussed by Stover
and Kincannon (4) and Stover, et al. (5), on the rates of nitrification
achievable by the nitrifying bacteria become important factors in the design
of this experimental approach. These influences on nitrification and the
dissolved oxygen consumed by the carbonaceous materials in the wastewater
limit this inhibition screening approach to low organic strength wastewaters.
The BOD bottles must be aerated daily during the test to minimize anaerobic
or anoxic conditions which could allow denitrification of the nitrate- or
nitrite-nitrogen produced.
50
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RESULTS
Due to concerns for obtaining reliable biological nitrification in a
combined municipal-industrial wastewater treatment facility, pilot plant
studies, industrial waste surveys and biological inhibition screening studies
were conducted to determine the effects of the industrial wastewater dis-
charges on a proposed single-stage activated sludge nitrification treatment
facility. Characteristics of the municipal and three industrial wastewaters
employed in microbiological nitrification inhibition screening studies are
presented in Table 2. These three major industrial contributors to the
municipal system account for less than 10 percent of the total wastewater
flow and BOD loading into the treatment facilities.
Results from the third day of testing the three industrial wastewaters
and the municipal wastewater (control) by the BOD bottle procedure with a
mixed culture of carbonaceous and nitrifying activated sludge as seed are
shown in Figure 1. The dissolved oxygen depletions do not distinguish be-
tween carbonaceous oxidation and nitrification, but this data does indicate
no apparent inhibition to biological oxidation in any of the wastewaters as
there were no threshold inhibition levels observed. The test was continued
for two more days to provide a five-day test condition. Dissolved oxygen
depletion remained high in all the BOD bottles with large volumes of waste-
waters (low dilutions) indicating no inhibition to biological treatment. At
the end of the five-day test period, even though all the oxygen demand had
not been satisfied in the low dilution bottles, the test was halted and the
contents of selected bottles were analyzed for nitrate-nitrogen production
(Table 3). Nitrate-nitrogen production was observed in all the bottles with
lowest concentrations appearing in the low dilution (high volume wastewater)
bottles in most cases. No apparent threshold inhibition levels to nitrifica-
tion were observed in these tests with the four wastewaters.
Due to the halting of the test at five days before exertion of most
of the oxygen demand in the low dilution bottles and the consequently low
nitrate-nitrogen production in some bottles, batch activated sludge nitrifi-
cation rate investigations were also conducted to verify the conclusions of
the BOD bottle test procedure. Environmental conditions, BOD loadings
(F/M ratios) and BOD/TKN ratios were monitored and controlled in each re-
actor to insure comparable test conditions. The nitrification rates ob-
served from these test reactors indicated the same conclusions as the BOD
bottle test with no nitrification inhibition occurring from these industrial
wastewaters (Figure 2).
Microbiological inhibition screening procedures were also conducted on
two samples of sanitary landfill leachate collected during different time
periods for assessment of the feasibility of treating the leachate in an
existing biological treatment facility. The leachate flow rate was estimat-
ed to be around one percent of the average daily flow through the treatment
facility, and the results of the characterization of the two samples are
presented in Table 4.
51
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TABLE 2. RAW WASTEWATER CHARACTERISTICS (mg/L EXCEPT pH)
.Parameter
COD
BOD
TKN
NH^-N
N02-N
NO -N
TDS
SS
PH
Percent
total
flow
Percent
BOD load
Municipal
wastewater
450
135
20
10
0.01
0.1
375
100
7.0
93
92
No. 1
500
150
30
10
0.4
0.1
1,100
600
8.5
4
4
Industrial wastewaters
No. 2
830
210
3
1
0.2
0.3
750
100
7.0
2
3
NO. 3
510
210
200
150
0.01
0.1
930
400
8.0
1
1
-------
O - CONTROL
A - IND. WASTE. NO. 1
D - IND. WASTE. NO. 2
O- IND. WASTE. NO. 3
INITIAL D. 0. LEVEL
RESIDUAL D. O. OF CONTROL
0.001
0.01
0.1 1.0
PERCENT OF SAMPLE BY VOLUME
10.0
100.0
FIGURE 1 RESULTS OF MICROBIOLOGICAL INHIBITION TESTING
OF INDUSTRIAL WASTEWATERS (CARBONACEOUS)
-------
TABLE 3. NITRATE-NITROGEN IN BOD BOTTLES AT FIVE DAYS (mg/L)
Bottle
No.
7
9
10
11
Wastewater
volume, ml
10
60
100
200
Municipal
wastewater
1.4
1.6
1.4
0.2
Industrial
No. 1
1.2
2.0
0.4
0.5
wastewaters
No. 2
5.0
6.9
4.7
3.3
No. 3
0.5
0.5
0.5
0.6
-------
0.020'
o
a
tr 0.010-
CONTROL
IND. WASTE. NO. 1
O JND. WASTE. NO. 2
0 JND. WASTE. NO. 3
CONTROL
3 4
TIME, HOURS
FIGURE 2 NITRIFICATION RATES (G NH3-N/DAY/G MLVSS)
DURING BATCH NITRIFICATION RATE STUDIES
55
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TABLE 4. LANDFILL LEACHATE CHARACTERISTICS
(MG/L EXCEPT PH)
Parameter Sample No. 1 Sample No. 2
COD
BOD
TSS
VSS
TDS
pH
12,000
6,600
150
51
9,400
5.5
17,000
900
460
230
3,200
3.3
During inhibition testing of the first sample where the BOD was around
50 percent of the COD value, no apparent threshold inhibition level to bio-
logical treatment was observed. However, during inhibition screening of the
second sample with the low BOD value (around 5 percent of the COD), a thres-
hold inhibition level to biological treatment was observed at about a dilu-
tion of one percent of the sample by volume as indicated in Figure 3. At
dilutions of leachate wastewater greater than 10 percent by volume, chemical
oxidation reactions were observed to consume oxygen and show up as an oxygen
demand (Figure 3) as determined by conducting a second set of tests with
sterilized wastewater and no biological seed. These test results verified
a concern for variable leachate chemical composition and the requirement of
physical/chemical pretreatment of the landfill leachate prior to discharge
to the biological system.
DISCUSSION AND CONCLUSIONS
The microbiological inhibition screening procedures previously presented
can be employed to provide estimates of the threshold inhibition levels for
both carbonaceous treatment and nitrification. The nitrification procedure,
as presented, is only applicable to low organic strength wastewaters, since
ammonia-nitrogen removal by synthesis reactions is the dominating or con-
trolling process over ammonia-nitrogen oxidation. A competing or crowding
effect of fast heterotrophic microorganism growth rates at increased changes
in influent organic concentrations has been observed to reduce nitrification
reactions in both fluidized and fixed bed reactors under conditions of excess
ammonia-nitrogen available for oxidation. (4,5,6,7,8) Since the nitrifica-
tion reactions would initially lag the carbonaceous reactions at the lower
dilutions, the BOD bottles must be reaerated and incubated until the car-
bonaceous oxygen consumption has leveled out. High organic strength waste-
waters would require running the test for long periods of time. The BOD
bottles must also be maintained under aerobic conditions after the nitrifi-
cation reactions have started to prevent denitrification of the nitrate-
nitrogen produced. The experimental design and interpretation of results
from the nitrification screening procedure must be conducted by an
56
-------
2
01
O
X
o
Q
LU
CO
LU
er
RESIDUAL D.O. OF CONTROL
0.00)
0.01
0.1 1.0
PERCENT OF SAMPLE BY VOLUME
10.0
100.0
FIGURE 3 RESULTS OF CARBONACEOUS MICROBIOLOGICAL INHIBITION TESTING
OF SANITARY LANDFILL LEACHATE
-------
individual with a thorough understanding of the nitrification process and
its influencing factors.
This nitrification inhibition screening procedure could be simplified
by the use of pure cultures of nitrifying bacteria (Nitrosomonas or
Nitrobacter) for biological seed and addition of ammonia-nitrogen or
nitrate-nitrogen as required by the wastewater characteristics under investi-
gation. By sterilization of the wastewater and addition of pure cultures of
nitrifying bacteria to the BOD bottles, the oxygen consumption measured
could be distinguished as nitrification, and the test procedure could be
simplified to the same format as that for carbonaceous inhibition screening.
Freeze-dried Nitrobacter has been employed as the test organism for
bioassay testing of toxicity in municipal and industrial wastewaters by mon-
itoring nitrite-nitrogen removal or nitrate-nitrogen production (9). Freeze-
dried bacterial cells eliminate the need for developing and maintaining an
active bacterial culture and provide a means of preserving the microorganisms
over long time periods for storage and shipping. By using freeze-dried
Nitrosomonas as the test organism in the BOD bottle, the first stage of
ammonia-nitrogen oxidation could easily be monitored for inhibition by sim-
ply monitoring oxygen uptake.
58
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REFERENCES
1. Marks, P. J., "Microbiological Inhibition Testing Procedure." Presented
at the Symposium of Environmental Monitoring ASTM Annual Meeting (1972).
2. Standard Methods for the Examination of Water and Wastewater, 14th ed.,
American Public Health Association, New York (1975) .
3. Gaudy, A. F., Jr., "Biochemical Oxygen Demand." In Water Pollution
Microbiology, John Wiley & Sons (1972).
4. Stover, E. L. and Kincannon, D. F., "Effects of COD: NH3-N Ratio on a
One-Stage Nitrification Activated Sludge System." Water and Sewage
Works, 123, 9, 120 (1976).
5. Stover, E. L., et al., "Inhibiting Nitrification in Wastewater Treatment
Plants." Water anfl Sewage Works, 123, 8, 56 (1976).
6. Stover, E. L. and Kincannon, D. F., "One-step Nitrification and Carbon
Removal." Water and Sewage Works, 122, 6, 66, (1975).
7. Saidi, H., "Studies on the Hydrolytically-Assisted Extended Aeration
Process and on Pre-Hydrolysis of Sludge in Aerobic Digestion Processes."
Master's Thesis, Oklahoma State University. Stillwater, Oklahoma (1974).
8. Murthy, K. S. N., "Operational Performance and Nitrifying Characteristics
of a Hydrolytically-Assisted Extended Aeration Process at High Organic
Loadings." Master's Thesis, Oklahoma State University, Stillwater
Oklahoma (1974).
9. Williamson, K. J. and Johnson, D. G., "A Bacterial Bioassay for
Assessment of Wastewater Toxicity." Presented at the 34th Purdue
Industrial Waste Conference, West Lafayette, Indiana (May, 1979).
59
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PB83-112208
TREATMENT OF MUNICIPAL WASTEWATERS CONTAINING BIOLOGICALLY
HAZARDOUS INDUSTRIAL COMPOUNDS BY CONVENTIONAL
ACTIVATED SLUDGE AND EXTENDED AERATION
by
D. F. Kincannon
Oklahoma State University
School of Civil Engineering
Stillwater, Oklahoma 74078
A. F. Gaudy, Jr.
University of Delaware
Department of Civil Engineering
Newark, Delaware 19711
T. S. Manickam
Oklahoma State University
School of Civil Engineering
Stillwater, Oklahoma 74078
ABSTRACT
Internal recycle bench scale reactors were used to study the effects of
phenol, 2-chlorophenol, methylene chloride, and 4-chloro,3-methyl phenol on
activated sludge and extended aeration processes treating a municipal waste-
water. The activated sludge process was operated at a mean cell residence
time of five days. The only solids wasted in the extended aeration units
were those used for analyses and whatever solids were in the effluent from
the final clarifier. The results of this study showed that the effluents of
the extended aeration pilot plants were lower in soluble COD and particularly
in suspended solids concentration than effluents from the 5-day 9C systems.
Increased suspended solids due to the presence of priority pollutants led to
operational problems in maintaining a steady mean cell residence time except
in the case of 4-chloro,3-methyl phenol. Presence of 4-chloro,3-methyl phenol
did not upset the steady mean cell residence time. There was no evidence for
massive pass through of any of the compounds for which specific analytical
determination was made even at the high dosage level of 50 mg/1.
INTRODUCTION
Wastewater treatment plants that are being constructed today are expected
to provide adequate, uninterrupted, stable removal of the influent organic
60
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components of the waste. Many sewers from various manufacturing plants tie
into the municipal sewer. Many industrial wastes, particularly those from
the chemical manufacturing industries, contain a variety of compounds which
may or may not be substrates for the heterogeneous microbial populations of
which activated sludge is composed. It is vital, therefore, to have reliable
data for determining the limits of compatibility and/or the required pretreat-
ment level for acceptance of questionable compounds into municipal plants.
The concentration effect of many organic compounds on natural biomasses in
municipal treatment plants is generally not known. Some waste components may
be toxic, while some may enhance the biological activity and vitality of the
sludge. On the other hand, some wastes may cause upsets at the plant for a
time and some may permanently cause a decrease in treatment efficiency. The
decreased efficiency may be in the form of greater leakage of soluble organic
matter or it may be due to interference with the floccing and settling ten-
dencies of the sludge in the secondary clarifier.
Earth and Bunch (1) have reported on the biodegradability and treatabil-
ity of various organic pollutants. Microbial cells were acclimated to 300
mg/1 of phenol and then fed 100 mg/1 of the test compound. Biodegradability
was measured by comparing oxygen uptake rates. They found that the biode-
gradability of a test compound could vary depending upon acclimation. Tabak
and Earth (2) studied the biodegradation of benzidine with acclimated extend-
ed aeration sludges. They found that complete oxidation of benzidine occurs
at benzidine concentrations of 1 mg/1. At higher concentrations less complete
oxidation occurred, however, no marked interference with carbonaceous removal
efficiency was noted.
Murray Strier (3), in an EPA internal report, has done an excellent job
in evaluating the treatability of 65 various organic chemicals. He has also
developed a procedure for predicting the biodegradation of organic chemicals.
The study reported on in this paper not only looked at the fate of the
organic compound but also its effect on the treatment process treating a
municipal wastewater
MATERIALS AND METHODS
Internal recycle continuous flow bench scale reactors were used for con-
ducting this study. The activated sludge units were operated at a hydraulic
retention time of 8 hours and an observed growth rate of 0.2 days"1
(0C = 5 days). The growth rate was maintained by proportional wasting of
mixed liquor after removing the baffle separating the aeration and settling
chambers. The extended aeration systems were operated at a hydraulic re-
tention time of 15.7 hours and no sludge other than that used for sampling
and the carry over from the clarifier was wasted.
The normal feed stock consisted of effluent from the primary clarifier
of the Stillwater municipal sewage treatment plant. A large supply of sewage
was obtained daily for this purpose. The BOD5 of the sewage was very low,
therefore, the sewage was supplemented with 200 mg/1 glucose and 75 mg/1
ammonium sulfate. To this base feedstock, various concentrations of the test
61
-------
compound were added as desired during the conduct of the experimentation.
Concentrations used were 5, 20 or 25, and 50 mg/1.
The major analytical technique employed was Chemical Oxygen Demand (COD),
as a measure of total and soluble organic matter in the influent and effluent.
Mixed liquor suspended solids and effluent suspended solids were measured
with a membrane filter (0.45y pore size). These analyses were run in accord-
ance with "Standard Methods for the Examination of Water and Wastewater"(4)-
Dissolved oxygen, pH, and temperature were measured periodically in the
reactors. Analyses were performed using a F and M Research Chromatograph
(Model 810) for the presence of the test compounds in the feed, mixed liquor,
and effluent.
RESULTS
Four compounds (phenol, 2-chlorophenol, methylene chloride,and 4-chloro,
2-methyl phenol) were chosen for study in continuous flow pilot plants oper-
ated at Un = 0.2 day"1 and also in extended aeration plants.
Phenol
Figure 1 shows the performance of an activated sludge unit operating at
a sludge age (6C) of 5 days before and after receiving phenol dosages of 5,
20, and 50 mg/1. The actual sludge age achieved in the unit gives a good
indication of the operational stability. Before phenol was introduced to the
unit a very stable 6C value was obtained. After 5 mg/1 phenol was introduced
to the reactor, the sludge age varied a great deal and then became more sta-
ble. However, when the phenol concentration was increased to 20 mg/1, the
sludge age again became unstable. With a phenol concentration of 50 mg/1,
the sludge age not only continued to be unstable but also decreased to a very
low level. It is also seen that the mixed liquor solids showed a gradual
decrease throughout the study. Effluent COD and suspended solids increased
sufficiently with the 50 mg/1 loading and during the cyclic changes. Table 1
gives a statistical summary of the data. The filtrate COD increased from an
average value of 30.3 mg/1 before the phenol loading to 99.0 mg/1 during the
cyclic changes.
The general impression received when one compares results shown in
Figure 2 for an extended aeration plant receiving varying dosages of phenol
with results for actived sludge at 6C = 5 days is that the extended aeration
pilot plant gave somewhat better results with respect to suspended solids
concentration in the effluent. However, it is clear that the presence of
phenol did cause some deterioration in effluent quality. It can be seen that
the addition of even 5 mg/1 phenol in the feed caused an increase in soluble
COD and a rise in suspended solids in the effluent. However, after the unit
had acclimated to this concentration of phenol, an increase from 5 to 20 mg/1
did not appear to affect the concentration of soluble COD in the effluent
although there was a short-lived rising trend in the effluent suspended
solids concentration. An increase to 50 mg/1 caused a rising tendency in
soluble COD and some increase in effluent suspended solids concentration.
62
-------
cr>
co
Kn BBB
*\PHENOi4-l
! r ' :
— 4—
-I—
\
\
III
I
t
ii
5«>
;rQ
03
800
INFLUENT CHARACTERISTICS
-»TOTALCOD-f
o FILTRATE COD
4OO|-°SUSPENDED SOLIDS-
EFFLUENT CHARACTERISTICS
300-"TOTAL COO
oFILTRATE COD
oSUSPEWDED SOLIDS
£
«
5
o
0-cr<
— s — K~
AjJ\>
}fl
I
KJ
"i
>v
V
\
w
fl
^
c*
°A
^>-o
V
Na,
CKV
•W
-CD
5 20 40 60 80 100 120 140 160
TIME. DAYS
Figure 1. Response of activated sludge system to phenol. 0C = 5 days.
-------
TABLE 1. STATISTICAL OPEPATIONAL DATA FOR STUDY UNITS
Priority Para-
Pollutant meters
Phenol N
X
N
X
N
X
N
X
N
X
2 N
Chloro X
Phenol
N
X
N
X
N
X
N
X
6 =
c
5 Days
Extended Aeration
Effluent
COD
MLSS
7
2053.6
11
1650.5
17
1154.7
14
1002.1
4
675.8
10
1275.8
13
1171.3
15
1253.5
21
1209.7
44
1036.7
Total
7
54.3
11
92.5
17
92.2
14
164.6
4
242.0
10
137.2
13
148.7
15
96.4
21
147.7
44
118.5
Fil
7
30.3
11
42.2
17
45.2
14
47.0
4
99.0
10
61.2
13
52.8
15
39.7
21
50.0
44
42.6
S.S
7
21.6
11
59.3
17
33.8
14
74.6
4
64.8
10
51.7
13
65.1
15
50.3
21
80.8
44
69.3
MLSS
25
1371.4
33
1734.2
16
1545.6
5
2329.2
13
2422.8
9
2414.0
11
2010.9
16
1550.0
21
1374.7
40
1526.0
Effluent
COD
Total
21
48.2
31
62.0
16
54.7
4
86.5
1
281.0
9
61.1
9
65.1
16
48.2
21
60.0
40
42.6
Fil
21
23.8
31
45.9
16
41.1
5
64.2
10
78.2
9
47.0
9
55.1
16
33.1
21
46.8
40
35.6
S.S
25
36.7
33
29.8
16
25.6
5
58.8
13
66.1
9
53.9
11
16.8
16
32.8
21
36.4
40
13.8
Remarks
No priority
pollutant added
5 mg/1 priority
pollutant added
20 mg/1 priority
pollutant added
50 mg/1 priority
pollutant added
Cyclic changes
No toxic com-
pound added
5 mg/1 priority
pollutant added
25 mg/1 priority
pollutant added
50 mg/1 priority
pollutant added
Cyclic changes
-------
TABLE 1. (continued)
tn
Priority
Pollutant
Methylene
Chloride
4
Chloro
3
Methyl
Phenol
Para-
meters
N
X
N
X
N
X
N
X
N
X
N
X
N
X
N
X
N
X
6
c
= 5 Days
Extended Aeration
Effluent
COD
MLSS
3
818.3
19
749.0
21
872.2
14
615.4
17
824.4
6
1635.8
17
1848.7
10
1780.6
12
1549.9
Total
3
198.0
19
162.1
21
142.8
14
188.5
18
170.8
5
93.0
17
62.3
10
57.9
12
88.4
Fil
3
48.0
19
47.0
21
37.1
14
51.4
18
57.4
6
75.3
17
55.2
10
46.2
12
56.8
S.S
3
109.3
19
85.4
20
96.7
14
108.6
18
93.1
5
23.4
18
7.6
10
6.0
12
26.9
MLSS
16
2008.8
16
1950.0
23
2204.3
14
1812.1
17
3287.6
6
4816.2
18
4843.6
10
5618.4
13
6407.0
Effluent
COD
Total
16
45.1
16
33.7
23
39.1
13
38.3
15
34.5
5
45.0
18
31.0
10
31.6
9
60.1
Fil
16
34.9
16
21.6
23
27.9
13
22.1
16
32.1
6
42.0
13
31.5
9
30.6
9
58.8
S.S
16
25.8
16
18.4
23
18.5
13
20.9
19
3.7
6
3.8
18
4.9
9
3.4
12
3.9
No priority pol-
lutant added
5 mg/1 priority
pollutant added
25 mg/1 priority
pollutant added
50 mg/1 priority
pollutant added
Cyclic changes
No priority pol-
lutant added
5 mg/1 priority
pollutant added
25 mg/1 priority
pollutant added
50 mg/1 priority
pollutant added
-------
0
PHI
gNOL
o
LJO
300
ouu
4OO
n
INFLUENT 1
~ A TOTAL COD
oFILTRATE C
a SUSPENDED
CHARACTERISTICS
OD
SOLIDS
^
ax*
ftk*
(*&•
Al
r
V
^
^J
*~T^
M
A
/w
(dtfM
P"**
A
[BST
iA
!V
o
0-0
^
^
OQ-
^
0-oJ
-o^P
^tr4«n
0*3^,
TT^cnr^rf
oo
EFFLUENT CHARACTERISTICS
"4 TOTAL COD
80 100
TIME, DAYS
Figure 2. Response of activated sludge system to phenol. Extended aeration.
-------
When the unit was subjected to shock loadings at the end of the experimental
period, the effluent COD did not increase to the extent experienced for the
faster growing sludge of Figure 1.
Statistical analysis on the operational data obtained from the extended
aeration process during the various periods of loadings is shown in Table 1.
It is seen that, on average, all dosages caused a somewhat higher total
effluent COD than was observed for the faster growing sludge in the control
unit. In general, it can be seen by comparing Figures 1 and 2 and the
statistical analyses (Table 1) that the extended aeration unit was subject
to a lesser amount of deterioration in effluent quality than was the faster
growing activated sludge. Microscopic examinations made during the experi-
mental period indicated there were rather large amounts of filamentous growth
in the extended aeration sludge as well as in the faster growing sludge. The
onset of filamentous growth in both units corresponded with the beginning of
phenol dosage and the filamentous growth continued to increase as phenol
dosage was increased. However, it increased at a significantly slower rate
in the extended aeration sludge than in the faster growing biomass.
2-Chlorophenol
Figure 3 shows the response of the continuous flow unit to varying dos-
ages of 2-chlorophenol.
After a short acclimation period the system could accommodate rather
well to the 5 mg/1 level of 2-chlorophenol. However, the suspended solids
concentration in the effluent was rather high. It became progressively
worse as the dosage was increased. It seems from these results that one may
expect that 2-chlorophenol will lead to higher effluent suspended solids con-
centrations which, in turn, make it difficult to operate the system at a
steady mean cell residence time as evident in Figure 3. This was more appar-
ent at a concentration of 25 mg/1 and above.
Figure 4 shows the performance of the extended aeration activated sludge
pilot plant receiving dosages of 2-chlorophenol. This activated sludge pilot
plant had previously been receiving phenol as a test compound. However, the
system had not been fed the previous test compound for at least 15 days prior
the initiation of data taking.
During the early stages there was a falling trend in the biomass concen-
trations. The suspended solids concentration in the effluent was rather low.
In general, during this period, the effluent from the extended aeration unit
was considerably better than that for the 5 day 6C activated sludge which
received similar dosage of the test compound. Shortly after increasing the
dosage to 50 mg/1, there was a noticable change in predominant species and in
appearance of the sludge. There was a decrease in protozoan population and a
concomitant increase in effluent suspended solids concentration which re-
sulted in a wide fluctuation in the mean cell residence time. However, with-
in three weeks the effluent solids concentration returned to its normally low
level and remained so during the pulsating loading period. Throughout the
remainder of the experimentation, the protozoan population increased but was
67
-------
do
z<
800
400|
400,
CH4RACTEWSTJCS
TOTAL OOP—•+—^
2000,
1000?
m
20
40
60
80
TIME. DAYS
100
120
I4O
160
Figure 3. Response of activated sludge system to 2-chlorophenol. 0C = 5 days.
-------
Hi
50ro-
150
INFLUENT CHARACTERISTICS
TOTAL COD
o FILTRATE COD
"SUSPENDED SOLIDS'
iiimiiuii mi uuuuiu
20
4O
60
80 100
TIME. DAYS
120
140
3
160
180
Figure 4. Response of activated sludge system to 2-chlorophenol. Extended aeration.
-------
not totally restored to the high level of activity observed before increasing
the concentration to 50 mg/1 in the feed.
Methylene Chloride
Results for the pilot plant which received varying dosages of methylene
chloride are shown in Figure 5. Statistical analyses for this unit showed
that prior to introducing the test compound the unit exhibited rather high
effluent suspended solids. Cyclical dosing with methylene chloride did not
appear to cause the system any more stress than steady dosing at 50 mg/1 nor
did the resting periods appear to help the system recover. The only notice-
able effect during cycling between 25 " 0 >• 25 mg/1 was the increase
in mixed liquor suspended solids. Much further study would be required in
order to provide a more scientifically satisfactory and informative assess-
ment of the effect of cyclical loading of this compound compared to a "steady
diet" of the compound.
The performance of the continuous flow unit which was operated as an
extended aeration activated sludge system is shown in Figure 6. Comparison
of the results shown in this figure for the extended aeration system with
those of Figure 5 for the faster growing system demonstrate, quite strikingly,
the better overall effluent quality of the extended aeration system and the
fact that the better quality effluent was due to its lower suspended solids
concentrations.
Periodic microscopic examinations of both sludges indicated that the
extended aeration sludge was much more flocculant and contained fewer fila-
ments and a greater number of protozoa than the faster growing sludge. Dur-
ing the period when the load was pulsed 50 •*• 25 >• 50 mg/1 or 25 >•
0 >• 25 mg/1, there was a slight increase in soluble COD in the effluent
but little or no change in effluent suspended solids concentration. There
was a rather significant increase in mixed liquor suspended solids during
the period of pulsating loading. The same general effect on mixed liquor
suspended solids was observed in the faster growing system (see Figure 5).
This effect, if sustained, could be important, particularly in the case of
extended aeration, since success of such a process is militated against by
build-up of mixed liquor suspended solids.
4-Chloro,3-Methyl Phenol
The response of an activated sludge pilot plant to varying dosages of
4-chloro,3—methyl phenol is shown in Figure 7. It is seen that the perform-
ance of the test unit was excellent. When the dosage was changed from 5 to
25 mg/1 there was a short-lived increase in filtrate COD. However, the sys-
tem rapidly recovered. There was considerably greater upset when the dosage
was increased from 25 to 50 mg/1. The COD leakage was associated primarily
with leakage of soluble COD in the effluent rather than COD due to effluent
suspended solids. However, it is clear from the experimental data that the
addition of this test compound at the concentrations studied herein can cause
temporary, if not long-lived, disturbance of effluent quality. Unlike other
priority pollutants studied herein, the presence of 4-chloro,3-methyl phenol
70
-------
O(J_J
I I i ! I I I I i| I I I I I mill |i 'P...I...J....L .1,. I I ~1
jlllllllllll.il IT I I mluu|iinln it n ] I n
INFLUENT CHARACTERISTICS
EFFLUENT CHARACTERISTICS
-« TOTAL COO
o FILTRATE COD
° SUSPENDED SOUD3
BIOLOGICAL
SOLIDS,
MG/L
— rv
-O 8 c
g
£
-------
Sif
50
E
ETHYLENE CHLORIDE)
J ' I f I I
IOQ
50
0
I I I I
VALUES ABOVE
ONE HUNDRED
_J I I
Qc/f
4000
00
20
40
60
80 100
TIME, DAYS
^P?
120
I4O
160
INFLUENT CHARACTERISTICS
TOTAL COO
o FILTRATE COD
a SUSPENDED SOUDS
EFFLUENT CHARACTERISTICS
COD
o FILTRATE COD
SUSPENDED SOLIDS
180
Figure 6. Response of activated sludge system to methylene chloride. Extended aeration.
-------
50
o1
P^ULO^O_^Lt«pHYL PHENOL]"
a
n
-i—r
t
rto-j^o
Or/j
UJ —
INFLUENT CHARACTERISTICS
80O -"TOTAL COOf
oRORATE 000
-"SUSPENDED SOLIDS
40O
200
100
0
EFFLUENT CHARACTERISTICS
-4TOTAL COOf
oHLTRATE COO
OSUSPENDED SOLIDS
4OOO!
2
m
2000
20
40 60
TIME. DAYS
80
100
Figure 7. Response of activated sludge system to 4-chloro,
3-methyl phenol. 9C = 5 days.
-------
did not cause any operational problems in maintaining a steady mean cell res-
idence time of about 5 days.
The performance of an extended aeration process dosed with varying con-
centrations of 4-chloro,3-methyl phenol is shown in Figure 8 and statistical
analyses of these data are presented in Table 1. It is clear from comparison
of Figure 8 with the performance of the faster growing system (see Figure 7)
that at 5 and 25 mg/1 dosage of the test compound the extended aeration sys-
tem provided much better effluent. The COD in the effluent increased during
the 50 mg/1 dosage level. The increase was due primarily to an increase in
soluble COD. Since the same tendency was noted in the control system during
this period of operation, it is difficult to say whether the increase in
soluble COD in the extended aeration pilot plant effluent was due to the in-
creased dosage of the test compound or was a natural consequence of some
unknown constituent introduced with the municipal sewage. In any event, it
is clear that prior to the occurrence the extended aeration process showed a
much greater ability to handle the test compound at significantly high dosage
levels, i.e., 5 and 25 mg/1.
Concentrations of Pollutants
Table 2 gives a summary for the quantitative analysis of the four pollu-
tants studied. It is seen that fairly good recovery was achieved in the
feed. It can also be seen that very low concentrations of the pollutants
were found in the mixed liquor and effluent except during the 25 > 50
cycle for 2-chlorophenol. A concentration of 31.0 mg/1 was found in the
effluent during this period.
CONCLUSIONS
Based on the results of pilot plant studies and upon observations during
the two-year experimental period, as well as results of auxiliary studies
made as the work progressed, the following conclusions with respect to the
4 priority pollutants seem warranted.
1. a. For the 4 compounds tested in the continuous flow activated sludge
pilot plants operated at 0C = 5 days (yn = 0.2 days"-'-) there was no
evidence for increased soluble COD in the effluent at the 5 mg/1 dos-
age. At this lower dosage, there was evidence for increased sus-
pended solids in the effluent of pilot plants dosed with phenol and
methylene chloride. At the higher dosage levels, there was evidence
for an increase in both soluble COD and suspended solids in the
effluent for the pilot plant dosed with phenol. For the units dosed
with 2-chlorophenol and methylene chloride, soluble COD in the efflu-
ent was not affected but there was some disturbance in effluent
suspended solids concentration. For the pilot plant dosed with 2-
chlorophenol and methylene chloride, cyclic loading led to increased
suspended solids in the effluent compared to control.
b. For the same 4 compounds tested in the extended aeration pilot plant,
there was evidence for increased soluble COD in the effluent only
74
-------
sis! 5°ffi
CHLOR0.3-METHVL PHENOI
(-0
u|4-ChLOR6.a-METHYL
Q! I I I II
d^ 0
Q 800
z<
INFLUENT CHARACTERISTICS
h-A TOTAL COD
oFILTRATE COD
—^SUSPENDED SOLIDS
0
200
EFFLUENT CHARACTERISTICS
COD(—
oFILTRATE COD
'^SUSPENDED SOLIDS
OtO_,
.J0
4000,
at
1
"^ O
V
P-CN
f>0
HX>
-1
r^o
«~«4
p^r
0^
^>0
ooJ
^
V
fl^
T
P-cx
-o-o
°-d
o__
20
40 60
TIME, DAYS
80
100
Figure 8. Response of activated sludge system to 4-chloro,3-methyl phenol.
Extended aeration.
-------
TABLE 2. RESULTS OF QUANTITATIVE ANALYSIS FOR REMOVAL OF TEST COMPOUNDS. (AVERAGE VALUES)
Name of
Compound
Phenol
2-chlorophenol
Methylene chloride
4-Chloro-3 Methyl
Phenol
Dosage
Level
mg/1
20
50
25-50 cycle
5
20
50
0-25 cycle
25-50 cycle
5
25
50
0-25 cycle
0-0-25 cycle
5
25
50
Concentration of compound Concentration of compound preseni
Present in the Unit (6 =5 days) in the extended aeration system
c
Feed
—
39.0
—
2.4
12.4
32.4
—
37.8
(50)
1.8
—
—
—
—
25.5
53.3
Mixed
Liquor
—
0
—
<0.001
0.02
—
—
<0.001
<0.001
<0.036
—
—
<0.08
<0.08
Settled Mixed
Effluent Feed Liquor
0.01 18.1
0.005
0
<0.01 3.0
0.012
—
<0.0064
31.0
0.4
<0.026
<0.055
8.5
<0.008
6.1
<0.08
1.1
Settled
Effluent
0.007
—
0
—
—
<0.0032
O.0032
—
—
—
<0.001
<0.001
<1.6
<1.05
<0.08
-------
from the unit dosed with phenol at the 5 mg/1 dosage level. There
was no increase in effluent suspended solids in any of the four sys-
tems at this dosage level. At the higher levels of dosage (20-25 and
50 mg/1) there was evidence for increased soluble COD and suspended
solids only in the units dosed with phenol. Also, only in the unit
dosed with"phenol was there evidence for disturbance of effluent
quality when dosage was changed on alternate days,
Based on the analyses made there was no evidence for massive pass
through of any of the compounds for which specific analytical deter-
mination was made even at the high dosage level of 50 mg/1. However,
small quantities of some of the compounds were detected in the
effluents.
2. From the results of this study there was evidence that the effluents of
the extended aeration pilot plants were lower in soluble COD and par-
ticularly in suspended solids concentration than effluents from compa-
rable faster growing systems. Among reasons for such results may be the
lower mass loading rate, i.e., higher biomass concentration and longer
mean hydraulic retention time. The reason for the lower suspended
solids concentration is probably due to generally greater abundance of
protozoa in this sludge as compared to the more rapidly growing system.
Generally in the faster growing systems, an increase in dosage of the
test compound appeared to cause more serious reduction in protozoan
activity than in the extended aeration system. Thus, while the biomass
with fewer grazing species could provide nearly equal efficiency with
respect to residual soluble COD, it was not possible with respect to
suspended solids concentration in the effluent. Therefore, it must be
concluded that in designing study procedures to assess effects of prior-
ity pollutants on activated sludges, the ecological considerations as
reflected in effluent clarity as well as other aspects of ecology, such
as limiting effects on species diversity, should be included as param-
eters for assessment.
3. Increased suspended solids due to the presence of priority pollutants
led to operational problems in maintaining a steady mean cell residence
time except in the case of 4-chloro,3-methyl phenol. Presence of 4-
chloro,3-methyl phenol did not upset the steady mean cell residence
time.
77
-------
REFERENCES
1. Earth, Edwin F. and Robert L. Bunch. "Biodegradation and Treatability of
Specific Pollutants." EPA-600/9179-034, Oct., 1979.
2. Tabak, H. H. and E. F. Earth. "Biodegradability of Benzidine in Aerobic
Suspended Growth Reactors." Journal Water Pollution Control Federation,
Vol. 50, No. 3, March 1979, p. 552.
3. Strier, Murray P. EPA Internal Report, June, 1977.
4. Standard Methods for the Examination of Water and Wastewater. 14th Ed.
American Public Health Association, New York.
ACKNOWLEDGMENT
This study was funded by the United States Environmental Protection
Agency Research Grant No. R-805242.
78
-------
PB83-U2216
THE TREATMENT -OF COMBINED INDUSTRIAL AND DOMESTIC
WASTEWATER FOR REUSE IN SOUTH AFRICA
J. van Leeuwen, L.R.J. van Vuuren, J.F.J. van Rensburg,
and A.J.R. du Plessis
National Institute for Water Research of the Council for Scientific
and Industrial Research, P- 0. Box 395, Pretoria 0001,
Republic of South Africa
ABSTRACT
South Africa is a- country with limited water resources. Consequently,
conservation measures, including the reclamation of water from both domestic
and industrial wastewater have been investigated. This paper describes the
experience-gained on various South African water reclamation plants, namely
a 32,000 m /d plant near Springs, east of Johannesburg, which produces water
for bleached pulp processing from domestic-industrial wastewater'treated in
a biofilter plant; a 12,000 m /d plant near Durban, which produces water for
fine paper production from domestic-industrial wastewater from an activated
sludge plant; the 4,000 m /d Stander plant in Pretoria, which produces po-
table water from biofilter and activated sludge effluents with little indus-
trial pollution; a 300 m /d pilot plant near Cape Town, which produces a
high-quality water from biofilter effluent of mainly industrial origin using
an integrated physical-chemical-biological process; and a 60 m /d pilot plant
in Pretoria which uses an integrated physical-chemical-biological process to
produce water of potable quality from settled wastewater of mainly domestic
origin. It was proved through inoculation of typical industrial pollutants
that this process could successfully remove all heavy metals and various
common organic compounds. All unit processes employed were necessary and
important for the removal of at least one pollutant.
INTRODUCTION
Despite the country's mineral riches, South Africa has a shortage of
water resources, particularly in the industrial growth centers. The Vaal
River, for instance, a river of modest flow (1,2 x 10 m /a) (1), is the main
source of water supply to more than 5 million people in the industrial heart-
land of the Pretoria-Witwatersrand-Vereeniging area. It is therefore not
surprising that the reclamation of water from wastewater (including indus-
trial effluents), for agricultural and industrial reuse, has become essential
as a means of supplementing existing water sources.
79
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REPRESENTATIVE WATER RECLAMATION PLANTS IN SOUTH AFRICA
The Sappi plant near Springs
The Enstra mill of the South African Pulp and Paper Industries Limited
(SAPPI), situated near Springs on the eastern Witwatersrand, has no water
supply on site. Underground water in the region originates from dolomitic
material and is therefore too hard for paper-making. The nearest source of
water of an acceptable quality is about 95 km. away (Rand Water Board).
About 30% of the production (some 600 t/d) is soda-oxygen pulp, while fine
paper constitutes less than a third of the production. Since most of the
process water therefore need not be of the best quality, SAPPI built a
32,000 m-Vd (8,5 mgd) reclamation plant to produce an industrial feed water
from secondary effluent from domestic sewage.
The influent to the local wastewater treatment plant consists of domes-
tic wastewater combined with industrial effluents from engineering and metal
finishing operations and from a meat-packing factory. The effluent from this
plant serves as the feed to SAPPI's reclamation plant (Fig. 1). Coagulation
with about 10 mg/L aluminium sulphate (as Al) and flocculation with 1,0 mg/L
polyelectrolyte give excellent flocculation and separation by flotation.
Marginal chlorination serves to polish the product. Sodium hydroxide (less
than 10 mg/L) is added for stabilization purposes.
w BALANCING
~n POND
k
f
AERATION 1
VESSEL [""""
H FLOTATION [!
UNIT (I
Figure 1. Flow diagram of the SAPPI water reclamation plant,
Springs (32,000 m3/d)
The reclamation process not only lessens turbidity and improves color,
but also removes much of the chemical oxygen demand (COD), detergents, phos-
phates, iron, copper and chromium. Brightness of test sheets of paper com-
pared favorably with those prepared from high quality Rand Water Board water.
About 2 c/m^ is being saved by using reclaimed water instead of Rand Water
Board water (2).
80
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Problems encountered with high concentrations of coloring matter in the
effluent from certain industries have been solved by diverting these effluents
to other wastewater treatment plants.
The Mondi plant near Durban
The Mondi paper mill near Durban comprises a groundwood pulp mill and
three paper machines for the production of about 750 t/d of newsprint and
fine paper. A good quality water, low in turbidity and color is required for
the production of fine paper. Dissolved organics, detergents, and phosphates
may all. cause specific problems and should be present in low concentrations
only.
The mill was established on an industrial site bought from the Durban
Corporation. A condition of sale was that a minimum of 9,000 m /d of secon-
dary effluent be used in the process. A reclamation plant of 12,000 m /d
(3 mgd) was constructed to produce a high-quality industrial water from acti-
vated sludge effluent. The influent to the wastewater treatment plant con-
sists of equal proportions of industrial and domestic effluent (3) .
The unit processes employed at the Mondi water reclamation plant can be
seen in Figure 2 and involve the following:
1. Aluminium sulphate coagulation (6 mg/L as Al, supplemented with
55 mg/L sulphuric acid, 25 mg/L lime and 2 mg/L floccotan poly-
electrolyte) ,
2. Upflow clarification (at 1 m/h) and sodium hydroxide stabilization,
3. Foam fractionation,
4. Primary chlorination,
5. Pressure sand filtration,
6. Activated carbon treatment (with in situ regeneration facilities),
7. Final chlorination and clear water storage.
The reclamation process reduces suspended material to virgually zero,
phosphates from 6,3 to 0,6 mg/L, detergents almost completely, COD by about
50% to an average of 43 mg/L and improves the color from 57 Hazen units to
7 (average values in 1976) (3).
A major difficulty was the presence of color in the wastewater from
textile wet-processing. This resulted in shortened actived carbon utiliza-
tion cycles and higher treatment costs. Stricter effluent control measures
taken by the Durban Corporation led to a greater improvement in plant
performance.
-------
aliminium polyetectrolyte
sulphate I
sodium
hydroxide
activated sludge
effluent *
Paper
mill
I MIXING
~P CHANNbL
v REACTOR |
" "fl CLAKIHhR
t t *
sulphuric 1 sludge
acid 1 i
lime dewatering
plant
backwash/water
chlorine
TANKS '
'
'
ACTIVATED A
TREATMENT ^
I '
t
CARBON
REGENERATION
v FOAM
"T\ FRACTIONATOF
air |c
4T
CLARIFIED
WATER
SUMP
i ,
SAND
FILTRATION
to
drain
chlorine
Figure 2. Flow diagram of the Mondi water reclamation plant,
Durban (12,000 m3/d)
The cost of Mondi's reclaimed water is very similar to that of potable
water, and includes the price of the secondary effluent purchased from Durban
Corporation. Mondi purchases both its potable water and secondary effluent
from Durban Corporation. Nevertheless, Mondi prefers using reclaimed water
as production is then less dependent on potable supplies that could be inter-
rupted in emergencies. In 1976, when floods necessitated a 29-day shutoff
of potable water supplies, and neighboring industries ground to a halt, pro-
duction at Mondi remained at full capacity. Mondi is at present carrying out
major extensions to its paper mill in Durban and is considering increasing
the use of treated wastewater as mill water supply (A. Giampietri, 1980'-
personal communication).
The Stander water reclamation plant, Pretoria
o
This 4,000 m /d facility (1 mgd) for the production of potable water
from secondary effluent was primarily intended for research and development.
The process was originally designed to treat biofilter humus tank efflu-
ent (from the treatment of mainly domestic wastewater). The unit processes
involved (4) were high lime coagulation, primary clarification in a floccula-
tion reactor/sedimentation tank, quality equalization in a large holding tank,
ammonia air stripping in a slatted tower, recarbonation, secondary clarifica-
tion, sand filtration, breakpoint chlorination, activated carbon absorption,
final chlorination and stabilization (Fig. 3).
-------
Ferric Polyelec-
chloride trolyte
Lime Chlorine
_POTABLE j j
WATER
ACTIVE
CARBON
REGENERATION
I
i
r
ACTIVE
CARBON
TREATMENT
i
CENTRIFUGATION
t
Sludge disposal
i
SAT
FILTR*
OZONATION
CHLORINATION
Figure 3. Flow diagram of the Stander water reclamation plant, Pretoria,
treating biofilter effluent (4,000 m3/d).
It was found that high lime clarification was very effective, not only
for the removal of turbidity, but also for partial disinfection and for con-
verting ammonium ions to the molecular form for later air stripping. Quality
equalization not only resulted in attenuation of diurnal quality variations
but was efficacious in partial ammonia stripping through surface aeration and
partial stabilization through carbon dioxide adsorption from ammonia (6), but
was economical only at ammonia concentrations higher than 5 mg/L (7). Recar-
bonation followed by secondary settling at a pH of about 10 resulted in par-
tial softening and excellent clarification. Sand filtration finally reduced
turbidity to about 0,7 Jackson turbidity units (JTU). Breakpoint chlorina-
tion removed ammonia and resulted in elimination of all pathogens (7). Acti-
vated carbon effectively removed most of the dissolved organic carbon and COD
to values consistently below 15 mg/d (8). Final chlorination and stabiliza-
tion resulted in a water of excellent potable quality (9).
The total cost of the reclaimed water was $0.30/m3 in 1977. At the
present escalation of costs of goods and services, the cost would be $0.42/m.
An analysis of costs reveals that scaling up of the operation to 40,000 m3/d
would reduce reclamation costs (1980) to $0.20/m3 (or $0.77 per 1,000 U.S.
gallons). The costs include amortization of capital (over 20 years at 11%
interest on balance) and all operational and maintenance costs. Scaling up
was done according to the method of Guthrie (10).
The Stander plant has also been used in more recent years to reclaim
water from activated sludge effluent (Fig. 4). The more consistent quality
81
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and lower ammonia concentrations in this effluent enabled elimination of
quality equalization and ammonia stripping (11). The need for a high pH to
facilitate ammonia stripping was eliminated and opened up the possibility of
using ferric chloride or aluminium sulphate as coagulant, which removed the
need for recarbonation. The smaller dosages of ferric chloride or aluminium
sulphate required, led to a saving in chemicals, while similar dosing mecha-
nisms reduced maintenance costs. The additional safety barrier against
pathogens afforded by the high lime treatment could be replaced by prechlori-
nation between the two clarification stages. Ozonation between sand filtra-
tion and activated carbon treatment resulted in a fourfold increase in opera-
tional life of the activated carbon (12).
Feme chloride
Chlorine
Activoted
sludge , , ~~
effluent
Lime
Ichlorin
i
or a umimum
sulphate
T
COAGULATION
REACTOR
ACTIVE
CARBON
REGENERAT
e
ON []f
\
1
PRIMARY
1 .
CLARIFIER
J
i p
Sludge recirculation
:NTRIFUGATION|
r
Disposal
Polyelectrolyte ^
i
Ferric chloride or
~~ aluminium sulphat
SECONDARY
REACTOR
CLARIFIER
„ *
i
SAND
FILTRATION
POTABLE
*
WATER
ACTIVE
CARBON
TREATMENT
OZONATION
OR
CHLORINATION
Figure 4. Flow diagram of the Stander water reclamation plant, Pretoria,
treating activated sludge effluent (4,000 nr/d)
Total costs could be reduced to $0.33/m3 (.4,000 m3/d scale) or $0.13/m3
on a 40,000 m3/d scale (or $0.47 per 1,000 U.S. gallons). Biological, chemi-
cal, epidemiological, toxicological, carcinogenic, teratogenic and mutagenic
tests have been conducted on the final water produced by both process config-
urations (13, 14, 15, 16). No adverse effects could be established and in
fact it was proved that the quality of the reclaimed water conformed to all
the quality criteria laid down by various regulatory bodies, including the
U.S. Environmental Protection Agency.
A plant to produce potable water from biofilter maturation pond effluent
for direct distribution was commissioned in Windhoek in 1969. The process
was very much the same as that applied at the Stander plant (17). Since 1979,
the Windhoek plant has also changed to the reclamation of potable water from
activated sludge effluent, and has already adopted most of the process modi-
fications (apart from ozonation) possible on the Stander plant. Since commis-
sioning, the plant has intermittently contributed up to 20% of Windhoek's
potable water needs (18). According to the City Engineer, the only
84
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complaints about reclaimed water quality were received when the reclamation
plant was not in operation ( A. J. Clayton, 1979 - personal communication).
The LFB pilot plant, Pretoria
3
The National Institute for Water Research (NIWR) developed this 60 m /d
pilot plant to investigate the feasibility of integrating biological waste-
water treatment with physico-chemical water reclamation. The original pro-
cess employed lime coagulation and flotation as pretreatment for activated
sludge treatment and was called the lime flotation biological (LFB) process
(19). Recent modifications included ferric chloride coagulation followed by
sedimentation and partial denitrification (20).
The incoming raw screened wastewater (7 to 10% industrial) is brought
into contact with recirculation streams from succeeding unit processes
(including fully nitrified effluent from the aerobic activated sludge process
unit) resulting in denitrification (Fig. 5). After ferric chloride coagula-
tion and flocculation, followed by sedimentation, the effluent passes through
a surface aerated activated sludge pond and then undergoes clarification
(after a secondary ferric chloride addition). Part of the sludge from the
clarifier is returned to the activated sludge pond. Part of the underflows
of the two clarifiers are returned to the denitrification unit. The excess
sludges are digested anaerobically.
Reclaimed ^_
water
Figure 5. Flow diagram of the LFB pilot plant, Pretoria (60 m3/d)
The overflow from the activated sludge clarifier is prechlorinated and
passed through a roughing filter and a dual media filter. The filtered
effluent then passes through an activated carbon column and is chlorinated
beyond breakpoint.
The pilot plant proved highly successful for the production of a good
quality water from untreated wastewater. The COD was reduced by more than
97,, to less than 10 mg/L (26 mg/L before activated carbon treatment). Ninety
eight percent of the nitrogen (as total Kjeldahl nitrogen) was removed and
the ammonia concentration in the final water was less than 0,2 mg/L.
85
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Phosphate was removed to less than 0,2 mg/L. The nitrate level was slightly
high at 11 mg/L (as N), but could be improved by increasing the recycle ratio
of nitrified effluent to the anaerobic reactor. The anaerobic treatment
could reduce the influent sulphate concentration by about 50%. Almost 80% of
the surfactants (measured as linear alkylbenzenes) were removed. The chlo-
ride and total dissolved solids levels increased owing to ferric chloride
addition and chlorination.
A capital, operational and maintenance cost estimate for this small
plant is possible as some of the unit processes are similar to those of the
Stander plant, for which these costs are available. The total capital cost
(4,000 m-Vd) on a discounted cash flow basis would be $0.095/m^ and the total
chemical cost $0.08/m (based on data published by van Vuuren and Taljard,
(20)). When all the other costs (electricity, operation, maintenance and
sludge disposal) are taken into account, the total cost is $0.36/m^, or
$0.15/m3 on a 40,000 m^/d scale. Although this cost is marginally higher
(about 10%) than that of reclamation of water from secondary effluent, it
should be appreciated that it includes the cost of secondary treatment
(normally 4 to 7c (U.S.))•
Athlone pilot water reclamation plant, Cape Town
o
A 300 m /d pilot plant, based on the original process development of the
LFB plant, was constructed to investigate water reclamation from wastewater
with a large proportion of industrial effluent. The Athlone sewage works has
heavily overloaded trickling filters which produce a poor effluent with a COD
of 220 mg/L, ammonia concentration of 36 mg/L and nitrate concentration below
1 mg/L (as N) on average (20).
This effluent serves as feed water to the pilot plant. The reclamation
process is initiated with high lime coagulation and flocculation with ferric
chloride and polyelectrolyte, followed by clarification (Fig. 6). This is
followed by air stripping of ammonia before a surface aerated activated
sludge unit. Ferric chloride and polyelectrolyte are then added before the
biological clarifier. Part of the underflow is returned to the activated
sludge unit, while the remainder is returned to the primary coagulation reac-
tor together with the return sludge from the chemical clarifier. The efflu-
ent is then chlorinated, sand filtered and passed through activated carbon
units before final chlorination.
The reclaimed water is of a good quality, with ammonia concentrations
of less than 0,2 mg/L (as N); COD, 22 mg/L; and total phosphate, 0,8 mg/L.
No coliforms, E4chejvu>chia. doLL, C£oA&u,ciLujn peA{tsiinge.yi&, ?&e.u.domon.(U>
a2Aug-t.fl0.6a., faecal streptococci or coliphages have been found in the re-
claimed water. The total dissolved solids concentration is about 800 mg/L,
mainly owing to the presence of chloride (233 mg/L as Cl), total hardness
(about 200 mg/L as CaC03) and sulphate (84 mg/L as 804). The turbidity is
lowered to 1,0 JTU, while the color is reduced from 205 in the biofilter
effluent to 9 Hazen units. The process removed 99.5% of the ammonia, 90% of
the organic nitrogen, 90% of the COD and more than 90% of the phosphate.
Iron, manganese and magnesium are also partly removed, while there is a large
increase in nitrate concentration (20).
86
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Biotilter
effluent
COAGULATION
REACTOR
CHEMICAL
CLARIFIER
^^
AMMONIA
STRIPPING
_.
AEROBIC
ACTIVATED
SLUDGE UNIT
Chlorine
FINAL WATER _ ACJ
TANK "~~ CQU
Polyelectrolyte *•
Carbon dioxide-
1VE CHLORINE
MNS TANK
BIOLOGICAL
CLARIFIER
»•
\
Chlorine
SAND
FILTRATION
Figure 6. Flow diagram of the Athlone pilot water reclamation plant,
Cape Town (300 m3/d)
The chemical dosing cost can be calculated by using data provided by
van Vuuren and Taljard (20) at $0.14/m3. If the projected full-scale capital,
operational, energy and maintenance costs are included, the total cost will
amount to $0.44/m3 (4,000 m3/d) or $0.21/m3 (40,000 m3/d).
UNIT PROCESS SELECTION FOR SPECIFIC POLLUTANT REMOVAL
The operational results of various pilot and small reclamation plants
demonstrate their capability to produce the desired quality water for potable
or industrial purposes, but since the raw waters are often mainly of domestic
origin, it was not always possible to predict the capacity of the processes
to cope with industrial pollutants. Two pilot plants were used to study the
efficacy of various unit processes in removing pollutants inoculated individ-
ually, namely the LFB (Fig. 5) and the BPC pilot plant, which was essentially
a 50 m3/d test facility based on the same process as the Stander plant treat-
ing biofilter humus tank effluent (Fig. 3).
Pollutants dosed
Nineteen different organic compounds (some highly toxic) were dosed at
nominal feed concentrations of 40 ug/L each for 30 h or longer (13, 21). In
parallel experiments with trace metals and other chemicals, loads as high as
0,5 mg/L cyanide and phenol (22, 23), 5 mg/L chromium, 1 mg/L cadmium and
150 ug/L mercury, arsenic and selenium (24) were inoculated. The efficacy of
the various unit processes employed in both plants is discussed below.
87
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Denitrification
The denitrification reactor as employed in the LFB pilot plant (with
recirculated nitrified effluent and chemical and biological sludges) removed
more than 98% of the metal ions with the exception of barium, which, with
phenol, was only partially removed. The recycling procedures in the plant
caused a buildup of cyanide within the sludge. Significant removals of up to
80% for 12 of the 19 organic compounds were obtained, with an average removal
of 37%. No significant buildup of these compounds through sludge recycling
was encountered.
Ferric chloride coagulation and clarification
This process also resulted in individual removal of more than 98% of the
metal ions, with the exception of barium (85%). Seventy-five percent of the
phenol was removed, while cyanide increased by 300% owing to sludge recycling.
Significant removals of up to 85% for 15 of the compounds in the unit process
feed, with an average of 35%, were obtained.
Aerobic activated sludge and biological clarification
Complete removal of mercury and most of the lead, cadmium, arsenic and
selenium, as well as phenol, was achieved in these units. The removal of
barium, hexavalent chromium and cyanide was poor. Up to 100% removal, with
an average of 69% for 16 of the organic compounds, was achieved. Naphtalene,
dichlorvos, anthracene, cresol, chlorophenol and S-naphtol were removed to
below their detection limits. The remainder (about 1%) of the acenaphthene,
hexadecane, dieldrin and phenol, represent nominal trace concentrations of
5 ug/L in the water.
Pre-chlorination and two-stage filtration
All of the lead, and most of the mercury, arsenic and selenium were
removed. Barium, hexavalent chromium and phenol removal was ineffective,
while 80% of the cyanide was removed. The pre-chlorination caused a removal
or breakdown of more than 99% of the polynuclear hydrocarbons, as well as
98 to 100% of the phenolic compounds. Filtration was generally ineffective
for the removal of the inoculated organic compounds, with the exception of
those that would adsorb to suspended matter in the water, for example, the
polynuclear aromatic compounds.
Activated carbon treatment
This proved to be an effective barrier against the passage of cadmium,
silver, lead, mercury, arsenic, cyanide and phenol. Most of the barium and
selenium was also removed, but no removal of hexavalent chromium was achieved.
All of the inoculated organic compounds were removed completely.
-------
Final chlorination
This final unit process was not studied separately because of the short
retention time and duplication of results achieved with pre-chlorination. In
the light of the removal rates achieved with activated carbon treatment, this
study would have been superfluous.
High lime coagulation and clarification
This unit process was only employed on the BPC pilot plant as an initial
treatment step for biofilter humus tank effluent. It was very effective for
the removal of lead, cadmium and mercury and to a lesser extent for zinc,
while copper and cyanide were ineffectively removed. The removal of organic
material closely resembled that of the other flocculation and sedimentation
processes.
DISCUSSION
It is possible to reclaim water from wastewater (including industrial
wastewater) for many applications. Water can be reclaimed to conform to any
quality criteria, including those for potable water. In many cases, re-
claimed water may be an economically viable alternative to water from conven-
tional, potable supplies. When reclaiming water from combined industrial and
domestic wastewater, cooperation between local authorities and industry is a
vital part of the success of the operation.
It may prove advantageous to consumers to be partially dependent on
reclaimed water; disruption in supply from one of the sources can then be
less damaging than disruption of a single supply.
In South Africa, the cost of potable reclaimed water is already approach-
ing that of drinking water obtained by conventional purification of surface
water. The average price the consumer paid for potable water in the eight
largest South African cities was $0.24/m^ in 1979,the major portion of this
cost being attributable to distribution and revenue to local authorities. If
distribution costs and revenue are to be added to the cost of reclaimed water,
it will have to be sold at a higher price than this. In many cases, however,
pumping costs of water from distant sources are high; and it may well prove
economical to distribute reclaimed water from wastewater sources which are
usually easily accessible.
The quality requirements for many industrial processes are lower than
for domestic reuse purposes. Water reclaimed from wastewater for a partic-
ular industrial reuse will therefore be a cheaper alternative than the
potable supply. The reclamation process should include only those unit pro-
cesses essential to achieve the specific quality objectives of the particular
industry. If the removal of hexavalent chromium is required, for instance,
this can be achieved by ferric chloride clarification, but activated carbon
adsorption would be ineffective. Cyanide and phenol can be effectively
removed more economically by a combination of activated sludge treatment and
89
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ferric chloride clarification, while cyanide could be removed at lower cost
by means of breakpoint chlorination. Activated carbon is effective for the
removal of a broad spectrum of pollutants, particularly organic compounds,
but many of these compounds -can also be removed by the activated sludge pro-
cess. Nevertheless, activated carbon is indispensable as a final contaminant
barrier in the production of potable water from wastewater.
Consideration should be given to the reuse of wastewater without inter-
mediate treatment. The variety of industrial processes and relatively low
irrigation water quality requirements in the Pretoria-Witwatersrand-
Vereeniging area lend themselves to water reuse without costly intermediate
treatment. Only in cases where no end user of a lower quality water is
available should reclamation of water from wastewater be considered.
Water reclamation not only offers an extension of the usefulness of a
given quantity of water, but can also play an important role in combatting
pollution. There are distinct environmental advantages to concentrating
toxic pollutants in sludge or on activated carbon as opposed to discharge
into rivers and streams particularly when reclaiming water from industrial
effluents. Prevention of pollution is usually better than its cure also from
an economical point of view.
ACKNOWLEDGEMENTS
The authors wish to acknowledge the following persons for providing data
and for valuable suggestions:
Mr. R. Smith - National Institute for Water Research;
Mr. M. L. Siebert - National Institute for Water Research;
Mr. J. W. Funke - National Institute for Water Research;
Mr. E. J. Smith - Research Laboratory, SAPPI Fine Papers (Pty) Ltd;
Dr. A. Giampietri - Mondi Paper Company;
Mr. A. F. Zunckel - Department of Water Affairs; and
Dr. F. C. Viljoen, Rand Water Board.
This paper is presented with the approval of the Director
-------
Conference of the LAWPR, Jerusalem, 8-23 June 1972, 627-636.
3. Giampietri, A., Funke , J.W. and Voysey, J.A. The reclamation of process
water from sewage effluent and the reuse of mill effluents and solids at
Mondi Paper Company, Durban, South Africa. PlOQ . WatZA Tiduwl. 10,
(1/2), 1978, 113-121.
4. Stander, G.J. , van Vuuren, L.R.J. and Dalton, G.L. Current status of
research on wastewater reclamation in South Africa. Wat. ?ollwt.
1Q_, (2) , 1971, 213-222.
5. van Vliet, B.M. , Wiechers, H.N.S. and Hart, 0.0. The efficacy of an
equalization pond in a water reclamation system. ?AOg. WateA Tncknot. ,
9_, 1978, 443-454.
6. Henzen, M.R. , Stander, G.J. and van Vuuren, L.R.J. The current status of
technological developments in water reclamation. ?Aog. WateA J
-------
15. Denkhaus , R. , Grabow, W.O.K. and Prozesky, O.W. Removal of mutagenic
compounds in a wastewater reclamation system evaluated by means of the
Ames Sa&nondULa. microsome Assay. To be presented at the Tenth Interna
tional Conference of the IAWPR, Toronto, 23-27, June 1980.
16. van Rensburg, S.J. , Hattingh, W.H.J. , Siebert , J.L. and Kriek, N.P.J.
Biological testing of water reclaimed from purified sewage effluents.
UateA Tec/inc£. , JJD, 1978, 347-356.
17. van Vuuren, L.R.J. , Henzen, M.R. , Stander, G.J. and Clayton, A.J. The
full-scale reclamation of purified sewage effluent for the augmentation
of the domestic supplies of the City of Windhoek. PfiOQ. Wat&L
2_, 1971, 32-41.
18. van Vuuren, L.R.J. , Clayton, A.J. and van der Post, B.C.
o£ WdteA fLidtcmcution at ulLndkoe.k. Presented at the 51st Annual Confer-
ence of the Water Pollution Control Federation, Anaheim, 1-6 October,
1978.
19. van Vuuren, L.R.J., Ross, W.R. and Prinsloo, J. The integration of
wastewater treatment with water reclamation. ?HOQ. WdteA T2.ch.nO-t., 9_,
1977, 455-466.
20. van Vuuren, L.R.J. and Taljard, M.P. The. X.&cJLama£u}n 0&
domestic. WCU>£ewa£&tt> . Presented at the American Water Reuse Symposium,
Washington, D.C., 25-30 March, 1979.
21. van Rensburg, J.F.J., Hassett , A., Theron, S. and Wiechers , S.G. The
fate of organic micropollutants through an integrated wastewater treat-
ment/water reclamation system. To be presented at the Tenth International
Conference of the IAWPR, Toronto, 23-27 June, 1980.
22. Siebert, M.L. The fate of phenol, cyanide, flouride and nitrate through
an integrated physical-chemical-biological water reclamation system.
(in preparation).
23. Smith, R. , Siebert, M.L. and Hattingh, W.H.J. Removal of inorganic
pollutants from wastewater during reclamation for potable reuse.
WatQJi S.A. , 6_, 1980.
24. Smith, R. and Wiechers, S.G. Elimination of toxic metals from wastewater
by an integrated wastewater treatment/water reclamation system. To be
presented at the Biennial Conference of the Institute of Water Pollution
Control (Southern Africa Branch), Pretoria, 2-6 June, 1980.
92
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PB83-ia2224
USE OF GRANULAR ACTIVATED CARBON TO TREAT MUNICIPAL
WASTEWATER RECEIVING INDUSTRIAL FLOW
P. B. DeJohn
J. P. Black
R. W. Edwards
ICI Americas Inc.
Wilmington, Delaware 19897
INTRODUCTION
Generally, for a plant to completely reuse their wastewater, high pollu-
tant (BOD, COD, color, etc.) removals must be attained. Granular activated
carbon, in either a physical chemical or a teriary mode, has been established
as an effective method of reducing pollutants to low levels. When zero dis-
charge standards are imposed, more and more plants will be turning to granu-
lar activated carbon treatment.
In an effort to assist anyone considering granular activated carbon
treatment, this paper will discuss the following:
• How to evaluate granular activated carbon.
• Adsorption data developed on municipal wastes.
• Adsorption data developed on various types of industrial wastes.
• The effect of thermal regeneration on the properties and performance
of granular activated carbon.
- How to select the best carbon for a given system.
- How to prevent undersizing a carbon system.
Possible symbiotic applications resulting from the thermal reactivation
of granular carbon include:
• Utilization of the carbon fines in other wastewater processes.
• Utilization of the heat content of the exit gases in other plant
processes.
93
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TEXT
How to Evaluate Granular Activated Carbon Isotherms
In order to determine if granular activated carbon can effectively treat
a given waste, one should first run an adsorption isotherm. An isotherm is
a plot on log paper showing the relationship between the amount of impurities
adsorbed on a unit weight of activated carbon and the amount of impurities
remaining in the wastewater.
To run an isotherm, carefully weighted quantities of carbon are added to
a constant volume of wastewater. The carbon-wastewater mixtures are agitated
vigorously for about 30 minutes. The carbon is then removed by filtration.
The treated water is analyzed for the level of impurities and the amount ad-
sorbed is found by difference.
The purpose in running an isotherm is to determine if carbon can reduce
the impurity level to the desired quantity. This relatively short screening
technique can usually show whether it is worth conducting time-consuming
column studies. Adsorption isotherms very rarely yield data reliable enough
to use for granular carbon system design because:
• Granular activated carbon is a good biological growth media. Carbon
in a column will develop a biological growth which will improve BOD removals
through the bed. Isotherms cannot predict these removals.
• Adsorption isotherms are equilibrium tests. The carbon will come
into equilibrium with all of the pollutants in the particular wastewater
sample being treated. Never does the carbon come into equilibrium with the
feed concentration in an isotherm test.
On the other hand, adsorption in a granular column is a dynamic phenom-
enon. As the wastewater moves through the granular bed, the carbon is con-
tinually adsorbing the more readily adsorbable organics and desorbing the
less adsorbable organics. This phenomenon has also been reported elsewhere
(1). Consequently, in a granular carbon system, if the contact time between
the carbon and the wastewater is not adequate, the more difficult to adsorb
organics will bleed through the bed because of this desorption phenomenon.
Obviously, when designing a granular carbon system, one attempts to
determine the optimum contact time to minimize or prevent this occurrence.
This information cannot be obtained from an isotherm!
Column Tests
The test consists of moving wastewater through at least four columns in
series containing granular carbon and measuring the amount of pollutant re-
maining in each column effluent. Samples of the feed entering the lead
column and also of the effluent from each column should be taken at regular
intervals (at least once per day). The "percent pollutant remaining" is
plotted for each column against time or volume of water treated. When the
pollutant concentration of the effluent from the last column in the series
94
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becomes greater than the standard allows (breakthrough), the test can be
stopped. Enough information is then available to:
• Determine the optimum contact time between the carbon and the waste-
water. The contact time is the major design parameter needed to size the
adsorption portion of the granular carbon system.
• Determine the carbon usage or exhaustion rate. The carbon usage rate
will tell one how much carbon must be reactivated per day. It is a major
design parameter needed to size the regeneration portion of the granular car-
bon system.
• Estimate preliminary investment and operating costs for a full-scale
plant.
Detailed methods on how to run an isotherm, how to conduct a column
study and how to analyze the data from a column study to adequately size a
granular carbon system are well documented in the literature (2) , (3) , (4).
Adsorption Data Developed on Municipal Wastes
ICI United States Inc. has conducted more than 50 comparative pilot
granular carbon studies on various types of municipal and industrial
wastewaters.
Tables 1 and 2 show comparative adsorption data from two studies con-
ducted on domestic wastewater at Marshall, Texas and Cortland, New York.
Equal volumes of carbon were compared in a tertiary mode at Marshall and a
physical/chemical mode at Cortland. These data are typical of all the
studies conducted on domestic wastewaters where we compared lignite and bi-
tuminous coal based granular activated carbons.
The data shows that both carbon types perform equally well on an equiva-
lent volume basis when treating domestic wastestreams regardless of the
treatment mode.
In the Marshall study, the carbons were compared through five adsorption
and four regeneration cycles. At Cortland, the evaluation was terminated
after 146 days and the effluents from the columns containing the two differ-
ent carbon types were still suitable. Consequently, the final system loading
would have been higher than reported.
In each study, the feed concentrations to the columns containing the
lignite and bituminous coal carbons were the same. The effluent concentra-
tions were, for all practical purposes, identical. The lignite carbon loaded
substantially higher than the bituminous coal carbon in the Marshall study
and slightly higher in the Cortland study.
Carbon loading is a measure of the pounds impurity removed per pound of
carbon applied. Carbon loading reflects carbon capacity for a given waste.
The carbon usage rate is a function of the carbon loading. The higher a
95
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TABLE 1 COMPARATIVE ADSORPTION DATA FROM A TERTIARY STUDY AT MARSHALL, TEXAS
Effluent from the plant's trickling filter was passed upflow through a
sand filter and downflow through two 6" I.D. carbon columns in parallel at a
fj
linear flow rate of 6.9 gpm/ft. One column contained 10' of an 8 x 35 mesh
lignite carbon and the other column 10' of a 12 x 40 mesh bituminous coal
carbon. Empty bed contact time was 11 minutes in each column.
The carbons were compared through five adsorption and four regeneration
cycles. Regeneration was done in a rotary tube laboratory activation fur-
nace, and the spent carbons were regenerated to the apparent densities of the
virgin carbons.
First Adsorption Cycle (Virgin Carbon)
Lignite Carbon Bituminous Coal Carbon
Avg. feed COD to carbon
column, ppm
Avg. effluent COD from
carbon columns, ppm
COD loading, Ib. total
COD/lb. carbon
54.5
35.6
0.312
54.5
37.7
0.230
Avg. feed COD to carbon
columns, ppm
Avg. effluent COD from
carbon columns, ppm
COD loading, Ib. total
COD/lb. carbon
Average For All Five Adsorption Cycles
Lignite Carbon Bituminous Coal Carbon
80.9
58.1
0.347
80.7
58.8
0.277
96
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TABLE 2 COMPARATIVE ADSORPTION DATA FROM A PHYSICAL/CHEMICAL STUDY AT
CORTLAND, NEW YORK
Effluent from the primary clarifier was fed to two sets of five 4" I.D.
carbon columns in parallel at a linear flow rate of 4 gpm/ft.^ Each set of
five columns was then operated downflow in series. Each column contained
3.2 ft. of carbon, giving a total bed depth of 16 ft. One set contained an
8 x 30 mesh lignite carbon and the other contained an 8 x 30 mesh bituminous
coal carbon. Empty bed contact time was 30 minutes through each set of five
columns.
The study was terminated after 146 days and the effluents from both
sets of columns were still suitable. Consequently, the final system loading
would have been considerably higher than reported.
Lignite Bituminous
Carbon Coal Carbon
Avg. feed BOD to carbon columns, ppm 52.7 53.2
Avg. effluent BOD from carbon columns, ppm 7.3 7.5
BOD removed, % 86<0 85>9
BOD loading, lb. BOD/lb. carbon 0.55 0.53
Avg. feed COD to carbon columns, ppm 97.2 97 6
Avg. effluent COD from carbon columns, ppm 26.0 28 7
COD removed, % 71>1 6g
-------
carbon loads, the longer it is able to remain in the adsorption cycle. Con-
sequently, the carbon usage rate will be less and a smaller regeneration
system might be justified.
Comparative Physical Properties of Lignite and Bituminous Coal Carbons
Tables 3 and 4 list the typical properties of 8 x 30 and 12 x 40 mesh
lignite and bituminous coal carbons. The most significant differences are in
total surface area, iodine number, molasses RE or molasses number, pore vol-
ume and bulk density.
Iodine number is a good measure of the surface area in the small pores
(micropores). Micropores are defined as those having an effective radius of
< 20 A° (5).
Molasses RE or molasses number gives a good indication of the surface
area in the transitional pore range. Transitional pores are defined as those
pores having an effective radii ranging from 20 A° to 500 A°, and pores
larger than 500 A° are defined as macropores (5).
Total surface area, as determined by the N2 BET method (6), measures all
of the above mentioned pore ranges.
Pore volume is a measure of the void space within the carbon particle—
the holes, and is determined by mercury intrusion.
Bulk density is normally defined as the density of a carbon after it has
been placed in an adsorber and has been washed and drained. It is the total
dry weight of carbon divided by the total volume occupied by that carbon
after washing and draining. Generally, the higher the pore volume, the lower
the bulk density.
The adsorption data just reviewed indicates that total surface area is
not a good predictor of how effectively a carbon will adsorb. Rather it
would appear that available surface area in pores of a size similar to the
size of the molecule to be adsorbed would best predict the effectiveness of
a carbon.
Since the lignite carbon has a higher surface area in the transitional
pore range than does the bituminous coal carbon, we concluded that break-
through was occurring because these pores were becoming exhausted.
Others have reported similar findings. Abram stated that pore volume
and surface area in the transitional pores are most used to remove organics
from a liquid phase. He also reported that to determine the most effective
carbon for a given application, the molecular size of the organic to be ad-
sorbed should be compared to the surface area and pore volume distribution of
the candidate carbons (7). The implication being that the best carbon will
be one having the most surface area and pore volume in the desired range.
98
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TABLE 3 TYPICAL PROPERTIES OF 8 x 30 MESH LIGNITE AND BITUMINOUS COAL CARBONS
8 x 30 Mesh
Total Surface Area
(N2 BET method) m2/g
Iodine Number, min.
3
Bulk Density, Ibs./ft.
Backwashed and Drained
Particle Density Wetted
in Water, g/cc
Pore Volume, cc/g
Effective Size, mm
Uniformity Coefficient
Mean Particle Diameter, mm
Pittsburgh Abrasion Number
NBS Abrasion No., %
Retention/mm
Moisture as Packed, max.
Molasses RE (Relative
Efficiency)
Ash
Mean Pore Radius
_
Bituminous Coal
Carbons (17, 18, 19)
950-1050
950
26
1.3-1.4
0.85
0.8-0.9
1.9 or less
1.6
70-80
70-75
2%
40-60
5-8%
14 A
Lignite
Carbons
500-650
500
23
1.3-1.4
1.0
0.75-0.90
1.9 or less
1.5
50-60
74-82
9%
100-120
12-18%
33 A
99
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TABLE 4 TYPICAL PROPERTIES OF 12 x 40 MESH LIGNITE AND BITUMINOUS COAL
CARBONS
12 x 40 Mesh
Total Surface Area
(N2 BET method) m /g
Iodine Number, min.
Bulk Density, lbs./ft.3
Backwashed and Drained
Particle Density Wetted
in Water, g/cc
Pore Volume, cc/g
Effective Size, mm
Uniformity Coefficient
Mean Particle Diameter, mm
Pittsburgh Abrasion Number
NBS Abrasion Number
Moisture as Packed, max.
Molasses Number
Ash
Mean Pore Radius
Bituminous Coal
Carbons (17, 18, 19)
1000-1200
1050
25
1.3-1.4
0.94
0.55-0.65
1.9 or less
1.0
70-80
70-75
2%
200-230
5-8%
14 A
Lignite
Carbons
550-700
550
23
1.3-1.4
1.0
0.55-0.65
1.9 or less
0.85
50-60
74-82
9%
450-500
12-18%
O
31 A
100
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Pittsburgh Chemical Company, Activated Carbon Division report in their liter-
ature that to adsorb color bodies and high molecular weight impurxties, pores
ranging from 20 to 500 A° are required (8).
Adsorption Data Developed on Various Ty^es_ oj Industrial Wastes
It follows that when treating waste streams containing pollutants with
predominately large molecules, the lignite carbon should perform best. That
is, the carbon dosage (Ibs. of carbon required to treat a given volume of
wastewater) should be less. The lignite carbon should load higher (remove
more Ibs. of impurity per Ib. of carbon applied) and should remain in service
for a longer period of time while producing a suitable effluent.
Tables 5 and 6 show comparative data from studies conducted on indus-
trial waste streams containing predominately large molecules. The lignite
carbon performed better than the bituminous coal carbon on an equivalent
volume basis.
In the same token, when treating a wastestream containing pollutants
with predominately small molecules, virgin bituminous coal carbon should
perform best.
Figures 1 and 2 show comparative adsorption data from a study conducted
by an east coast dye manufacturer (9) . Isotherms were run comparing pulver-
ized versions of virgin 12 x 40 mesh lignite and bituminous coal carbons.
The dyes used in this study ranged in molecular weight from 350 to 1,370.
The bituminous coal carbon performed better than the lignite carbon with
respect to dye removal and loading on the low molecular weight dyes. However,
as the molecular weight (hence, molecular size) increased, the performance of
the lignite carbon became better than that of the bituminous coal carbon. A
summary of the results are:
% Dye Removal* Loading**
Dye Lignite Coal Lignite Coal
Molecular Weight Carbon Carbon Carbon Carbon
350 93 99 .21 .40
700 61 40 .10 .07
810 68 50 .17 .11
890 42 23 .08 .04
1370 65 38 .13 .08
*At a pulverized carbon dosage of 5,000 ppm.
**Lbs. of dye removed/lb. of carbon applied at 50% color
removal.
Effect of Thermal Regeneration on the Adsorption Performance of_ Carbon
When granular activated carbon is reactivated, the internal pore struc-
ture of the carbon is altered. Surface area in the small pore (micropore)
range is drastically reduced, and transitional pore surface area is increased
slightly. Reasons for this phenomena are well documented (10, 11, 12).
101
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TABLE 5 COMPARATIVE ADSORPTION DATA FROM A STUDY CONDUCTED ON AN EAST COAST
DYE WASTE
A column study was conducted on a dye waste from an East Coast dye
manufacturing and processing company. The waste was sand filtered and then
fed to two sets of three 1-1/2" I.D. columns operated in parallel at a linear
n
flow rate of 0.52 gpm/ft. Each set of three columns was then operated
downflow in series. Empty bed contact time was 88 minutes through each set
of three columns. One set contained an 8 x 35 mesh lignite carbon and the
other contained an 8 x 30 mesh bituminous coal carbon.
Avg. feed color, absorbance
wave length
Effluent color, absorbance
wave length (60% color
Time it took for carbon to
(in hours)
Carbon dosage required, Ib.
Lignite
Carbon
at 525 my 1.123
at 525 my 0.449
removal)
breakthrough 197
/I, 000 gals.* 25.4
Bituminous
Coal Carbon
1.123
0.449
69
83.4
* These are the calculated dosages at 60% removal; dosages would be signi-
ficantly lower in a countercurrent system.
102
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TABLE 6 COMPARATIVE ADSORPTION DATA FROM STUDIES CONDUCTED ON TWO DIFFERENT
EAST COAST OIL REFINERY WASTES
Case 1. A column study was performed on sand filtered, API separator efflu-
ent from an East Coast oil refinery. Two sets of three 1-1/2" I.D.
carbon columns were operated in parallel at a linear flow rate of
2 gpm/ft.2 Empty bed contact time was 18 minutes through each set
of three columns. Each set of three columns was then operated up-
flow in series. One set contained a 12 x 40 mesh lignite carbon,
and the other set contained a 12 x 40 mesh bituminous coal carbon.
Avg. feed COD to carbon columns, ppm
Effluent COD from carbon columns*, ppm
Carbon Dosage, lb./l,000 gals.
Loading on carbon, Ib. COD removed/lb.
of carbon
Lignite
Carbon
104
31
0.93
0.65
Bituminous
Coal Carbon
104
31
1.31
0.46
Case 2. A column study was performed on sand filtered, API separator efflu-
ent from another East Coast oil refinery. Two sets of four 1-1/2"
I.D. carbon columns were operated in parallel at a linear flow rate
r\
of 0.5 gpm/ft. Each set of four columns was then operated down-
flow in series. Empty bed contact time was 88 minutes through each
set of four columns. One set contained an 8 x 30 mesh lignite car-
bon, and the other set contained an 8 x 30 mesh bituminous coal
carbon.
Avg. feed COD to carbon columns, ppm
Effluent COD from carbon columns*, ppm
Carbon dosage, lb./l,000 gals.
Loading on carbon, Ib. COD removed/lb.
of carbon
Lignite
Carbon
70
21
1.91
0.21
Bituminous
Coal Carbon
70
21
2.49
0.16
*Breakthrough at 70% removal.
103
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FIGURE 1
RELATIONSHIP BETWEEN DYE
MOLECULAR WEIGHT AND % DYE REMOVAL
AT A CARBON DOSAGE OF 5000 PPM
100
Ul
O
a
z
o
CD
CC
o
5
40
-------
FIGURE 2
RELATIONSHIP BETWEEN DYE
MOLECULAR WEIGHT AND CARBON
LOADING @ 50% DYE REMOVAL
o
CO
= 0.3
<
O
LL
O
ca
Q
LU
O 0.1
5
UJ
cr
UJ
0.03
5
x
BITUMINOUS
COAL CARBON
300 500 700 900 1100 1300
DYE MOLECULAR WEIGHT
105
-------
The significance of this change in pore structure is that the adsorptive
performance of a regenerated carbon can change drastically. The degree of
change will depend on the nature of the organics to be adsorbed. If the or-
ganics are relatively large molecules, the performance of the reactivated
carbon should be equal to or better than that of the virgin carbon. However,
if the organics are relatively small molecules, the performance of the re-
generated carbon will decrease substantially.
The reasons are:
• Large molecules are adsorbed in the transitional pores which are
essentially unaffected in the thermal regeneration process.
• Small molecules are adsorbed in the micropores, a good portion of
which are lost during reactivation.
Table 7 shows data developed at an east coast dye manufacturing plant
(9). Isotherms were run with a virgin and a regenerated bituminous coal car-
bon using different molecular weight dyes. The performance of the reacti-
vated carbon, as compared to its virgin counterpart, decreased considerably
with the low molecular weight dye; but as the molecular weight of the dye
(hence, molecular size) increased, the regenerated carbon performance was
essentially the same as its virgin carbon counterpart.
Another east coast dye manufacturer, prior to conducting a column study,
ran isotherms with pulverized samples of virgin 12 x 40 mesh lignite and
bituminous coal carbons. The carbons in the column were exhausted and re-
generated. Isotherms were then run on pulverized samples of the reactivated
carbons. Figure 3 shows the isotherms (9).
The virgin bituminous coal carbon performed better than the virgin lig-
nite carbon. This indicates that the waste contained predominately small
molecules. The performance of the regenerated lignite carbon with respect
to its virgin counterpart was essentially unchanged. The performance of the
regenerated bituminous coal carbon was significantly poorer than its virgin
carbon counterpart.
Although the virgin bituminous coal carbon performed better than the
virgin lignite carbon at all dosage levels, the regenerated lignite carbon
performed better than the regenerated bituminous coal carbon at the low car-
bon dosages.
The implications are:
• If the wastestream contains predominantly small molecules (this can
be determined by comparing the relative performance of lignite and
bituminous coal carbons on the same waste), data developed using
regenerated carbon should be used to design the granular carbon sys-
tem. Otherwise, the system can very easily be undersized.
If regenerated carbon is not available, the system should be designed
from data developed using a virgin lignite carbon. The reason is
106
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TABLE 7 ISOTHERM STUDY DONE BY AN EAST COAST DYE MANUFACTURER COMPARING
THE PERFORMANCE OF A VIRGIN AND REGENERATED BITUMINOUS COAL CARBON
Dye Molecular
Weight
350
810
1370
Powdered Carbon
Dosage, ppm
2000**
6000
6000
Virgin Bituminous
Coal Carbon
86
44
26
% Dye Removed*
Regenerated Bituminous
Coal Carbon
61
41
29
* Initial dye concentration, 1000 ppm.
** 100% dye removed by both carbons at 6000 ppm dosage.
-------
Q
u E
> a
O a-
QC OQ
O CC
-J <
O O
O
Figure 3
COMPARATIVE ADSORPTION ISOTHERMS ON
VIRGIN AND REGENERATED LIGNITE
AND BITUMINOUS COAL CARBONS
C0 =2500
.5
VIRGIN BITUMINOUS
COAL CARBON
.2
.1
VIRGIN
LIGNITE
CARBON
REGENERATED
BITUMINOUS
COAL CARBON
X REGENERATED
XLIGNITE CARBON
200 1000 2500
ADMI COLOR REMAINING
108
-------
because regenerated lignite carbon performance is similar to virgin
lignite performance in wastestreams of this type.
• If the wastestream contains predominantly large molecules, the sys-
tem can be designed based on the virgin carbon data; because the per-
formance of the regenerated carbon will be at least as good as that
of the virgin carbon.
Symbiosis
Utilization of the Carbon Fines in Other Wastewater Processes
When any granular activated carbon is transported and regenerated, the
carbon will attrite to a certain degree and carbon fines will be created.
These carbon fines are in essence powdered activated carbon.
It is well known that powdered activated carbon will improve treatment
in activated sludge and anaerobic digestion systems (13, 14, 15, 16).
A daily influent powdered carbon dosage of about 15-50 ppm to an acti-
vated sludge system will improve plant operations by:
• Increasing BOD, COD, and TOC removals despite hydraulic and organic
overloads.
• Aiding in solids settling, decreasing effluent solids and yielding
thicker sludges.
• Adsorbing dyes and toxic components that are either not treated
biologically or are poisonous to the biological system.
• Reducing aerator and effluent foam by adsorption of detergents.
• Preventing sludge bulking over broader F/M ranges.
• Improving nitrogen removal.
• Giving more uniform plant operation and effluent quality, especially
during periods of widely varying organic or hydraulic loads.
A daily influent powdered carbon dosage of about 5-10 ppm to an anaero-
bic digester will:
• Improve supernatant quality thus reducing the load placed on the
hydraulic part of the plant by decreasing fine solids recirculation.
• Increase digester gas production by catalyzing the destruction of
volatile solids.
• Decrease the volume of volatile solids that a plant has to handle
because of the increased destruction of these volatile filter
operations.
• Improve the dewaterability of the inert solids drawn from the bottom
of the digester. This will result in improved filter operations.
Carbon fines in a granular carbon system usually appear in backwash and
overflow waters, and in the wet scrubber or dust collector of the
109
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regeneration system. Usually, these fines are recirculated to the front end
of the plant and are settled out in the primary clarifier. Or, the fines
collected in the dust collector are disposed of with other plant sludges.
It would appear that one could take these fines and add them directly to
the aerator of an activated sludge unit.
The fines should improve the quality of the activated sludge effluent.
This would mean that the organic load to the granular carbon system would be
lightened. This should result in lower carbon usage rates as well as an im-
provement in overall plant performance. Or, one could add the fines to any
unit where carbon will end up in an anaerobic digester (e.g., a thickener).
Utilization of the Heat Content of the Exit Gases in Other Plant Processes
The furnaces used to regenerate granular activated carbon usually are
equipped with an afterburner. Gases exiting the afterburner are generally
at temperatures of 1,200°-1,400°F. These gases are normally vented to the
atmosphere or passed through a wet scrubber.
When the flue gas is vented, it would appear that the heat content of
these gases could be used elsewhere in the plant. For example, one could
take these gases and pass them through a waste heat boiler or a heat ex-
changer. Where applicable, process streams could be heated up by these gases,
and one could defray some of the costs associated with steam generation.
Summary and Conclusions
In summary,
• Isotherms should be used to determine if carbon can reduce the im-
purity level to the desired quantity.
• Running comparative isotherms between lignite and bituminous coal
carbons will give a good indication of the relative size of the pollutant
molecules in a given waste. If the isotherms show the virgin lignite carbon
to be best, the stream contains predominately large molecules. This means
that breakthrough will occur when the transitional pore surface area becomes
exhausted. If the opposite is true, the waste contains predominately small
molecules. This means that breakthrough will occur when the micropore sur-
face area becomes exhausted.
• Granular carbon systems should be designed on data developed from
column studies—not isotherms.
• Lignite carbons perform better than bituminous coal carbons in waste-
streams containing predominately large molecules.
• Virgin bituminous coal carbons perform better than virgin lignite
carbon in wastestreams containing predominately small molecules. However,
once either carbon is regenerated, surface area in the small pore range is
110
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lost. After about 5-6 regenerations, the performance of both carbon types
should be equivalent in waste streams of this sort.
If the wastestream contains predominately small molecules, the granu-
lar carbon system should be designed on the basis of the performance of re-
generated carbon. If regenerated carbon is not available, the lignite carbon
should be used to obtain the design parameters. The reason being that lig-
nite carbon properties do not change as much as bituminous coal carbon prop-
erties upon regeneration.
Using the fines generated by transporting and regenerating granular
activated carbon in either an activated sludge or an anaerobic digestion
process may be feasible.
The heat value of the exit gases from a carbon regeneration furnace
might find use in other plant processes.
REFERENCES
1. Keinath, T. M. , "Design and Operation of Activated Carbon Adsorbers Used
for Industrial Wastewater Decontamination," presented at the 68th Annual
Meeting of American Institute of Chemical Engineers, Los Angeles, Cali-
fornia, Nov. 19, 1975.
2. Hutchins, Roy A., "New Method Simplifies Design of...Activated Carbon
Systems," Chemical Engineering, August 20, 1973.
3. Anon., "Adsorption Isotherm of Granular Carbon for Wastewater," PC-2,
ICI United States Inc., Wilmington, Delaware.
4. Anon., "Evaluation of Granular Activated Carbon in Columns for Wastewater
Treatment," PC-3, ICI United States Inc., Wilmington, Delaware.
5. Smisek, M. and S. Cerny, "Active Carbon," pp. 56-57, American Elsevier
Publishing Company, New York, 1970.
6. Brunauer, S., P. H. Emmett and E. Teller, Journal American Chemical
Society, 60, 309, 1938.
7. Abram, J. C., "The Characteristics of Activated Carbon," presented at
Water Research Association Conference, University of Reading, England
April 3-5, 1973.
8. Anon., Product Data Bulletin, Pittsburgh Type SGL Granular Carbon,
Pittsburgh Chemical Company, Activated Carbon Div., Pittsburgh,
Pennsylvania.
9. DeJohn, Paschal B. and Hutchins, Roy A., "Treatment of Dye Wastes with
Granular Activated Carbon," presented at The National Technical Confer-
ence of the American Association of Textile Chemists and Colorists,
Chicago, Illinois, Oct. 15-17, 1975.
Ill
-------
10. DeJohn, Paschal B., "Factors To Consider When Selecting Granular Acti-
vated Carbon for Wastewater Treatment," presented at the 29th Purdue
Industrial Waste Conference, Purdue University, West Lafayette, Indiana,
May 7-9, 1974.
11. Hutchins, Roy A., "Economic Factors in Granular Carbon Thermal Regenera-
tion," Chemical Engineering Progress, November, 1973.
12. DeJohn, Paschal B., "Carbon From Lignite or Coal: Which is Better?",
Chemical Engineering, April, 1974.
13. Adams, Alan D., "Powdered Carbon: Is It Really that Good?", Water &
Wastes Engineering, March, 1974.
14. Clapp, Kenneth Edward, "Granular To Powdered Activated Carbon in Pol-
luted Water Purification Process," United States Patent, October 23,
1973.
15. DeJohn, Paschal B. and Adams, Alan., "Activated Carbon Improves Waste-
water Treatment," Hydrocarbon Processing, October, 1975.
16. Adams, Alan D., "Activated Carbon: Old Solution to Old Problem,"
Water & Sewage Works, August and September, 1975.
17. Internal ICI United States Inc. report, "Competitive Carbon Study."
18. Anon., Calgon Activated Carbon Product Bulletin 20-2C, Filtrasorb 300
and 400 for Wastewater Treatment, Calgon Corporation, Pittsburgh,
Pennsylvania, 1970.
19. Anon., Product Data Bulletin, Nuchar Granular Active Carbon, Grade:
Nuchar WV-L 8 x 30, West Virginia Pulp and Paper, Covington, Virginia.
20. Anon., Product Data Bulletin, Nuchar Granular Active Carbon, Grade:
Nuchar WV-G 12 x 40, West Virginia Pulp and Paper, Covington, Virginia.
112
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PBS 3-142232
FULL SCALE EXPERIENCE WITH ACTIVATED CARBON TREATMENT OF
JOINT MUNICIPAL - INDUSTRIAL WASTEWATER
J. L. Taylor
City of Fitchburg
Wastewater Treatment Facilities
Lanides Lane, Fitchburg, Massachusetts 01420
ABSTRACT
In the late 1960's, Fitchburg, like many communities, found itself faced
with a serious water pollution problem. An engineering firm was hired to
recommend and design a solution to the problem. Their recommendation re-
sulted in the construction of two (2) new advanced Wastewater Treatment Facil-
ities. One of these facilities, the West plant, is a physical-chemical plant
designed mainly to service the area's paper manufacturing facilities. Since
plant startup, in mid 1975, numerous mechanical and process difficulties have
occurred. The plant has operated in a continuous mode for only a relatively
short period of time. Experiences at Fitchburg as well as other physical-
chemical treatment plants have made certain factors obvious. It has also
shown that numerous questions remain to be answered.
TEXT
In the early 1960's, pressure began building concerning the quality of
Massachusetts Waterways. Fitchburg, being a heavily industrialized city, was
directly affected by this pressure.
Fitchburg is located at the headwaters of the north branch of the Nashua
River. Flow in this stream varies dramatically on a seasonal basis. Usually
the dry weather flow is about 10% of the wet weather flow and under draught
conditions, almost the entire flow through the City of Fitchburg is paper
mill effluent.
The City commissioned an engineering firm in 1967 to study its pollution
problems and recommend a course of action. The firm recommended abandoning
the City's existing trickling filter plant and constructing two new Waste-
water Treatment Facilities. One of these facilities, the East plant, would
replace the old trickling filter plant and serve the majority of residential
and commercial properties. The other would be located in West Fitchburg and
primarily service the area paper mills. About 10% of the plant flow was
anticipated to be domestic sewage.
113
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Fitchburg's paper mills are speciality grade production facilities. The
majority of the paper manufactured is either colored or chemically treated
with silicones, latexes or starches.
The original facility design recommendation for handling the paper mill
waste in West Fitchburg was an activated sludge plant. Later, the design
recommendation was changed to an activated carbon facility for the following
reasons: i "'.
- #
1. The extreme fluctuations in 'w'astewater characteristics discharged
from the industries making it extremely difficult to maintain a
high quality effluent from a biological system.
2. The belief that the activated carbon process would be better able
to meet more stringent discharge standards so future plant upgrad-
ing would not be necessary.
3. The uncertainty of the color removal capabilities of a biological
treatment system.
The West Fitchburg Wastewater Treatment Facility is one of two advanced
Waste Treatment Plants which were started up by the City in the latter half
of 1975. The plant is designed for 15 MGD and normally averages eleven (11)
to thirteen (13) MGD. Of that flow, roughly two (2) percent is of domestic
origin. The domestic waste receives primary settling and chlorination prior
to being mixed with the main inflow stream. The majority of the influent is
generated at the area paper production facilities. A total of five (5) pro-
duction facilities, plus a central power plant, discharge their wastewater to
the West plant.
The treatment plant processes include chemical coagulation utilizing
alum, lime and polyelectrolytes, flocculation, settling, and then filtration
through activated carbon units. The effluent is aerated prior to discharge
at the headwaters of the North Nashua River. Solids handling facilities con-
sist of gravity thickening followed by earthen dewatering lagoons and land
burial. The plant does have facilities for onsite thermal reactivation of
the activated carbon. The 12 downflow pressure carbon filters are backwashed
daily with filtrate. Hydraulic transferring of the carbon and other plant
water usages are also supplied from the filter effluent.
The plant was designed to produce an effluent quality of 8 MS/L for
both BOD5 and TSS on a monthly average. The cost of operating and maintain-
ing the facility is shared by all users and is apportioned based on the flow,
suspended solids and organic loadings.
Full plant operation has been limited due to a series of mechanical and
process difficulties. The first major setback was with the primary sludge
pumping system. Complete system modification took over a year, but a tempo-
rary installation allowed the facility to operate receiving partial flow until
a permanent solution was developed. During this interim period, work started
on debugging the activated carbon system. Soon after starting the carbon
filtration system, one of the filter units exceeded its pressure rating which
114
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caused the protective relief valve to open. The dram pipe receding this
flow had been buried with a temporary plug at one location and subsequently,
a section of the floor slab was lifted until it cracked and relieved the pres-
sure. As a result, the buried line was abandoned and replaced with a new
pipe above the floor slab.
As run time of the carbon filters accumulated, the generation of Hydro-
gen Sulfide within the carbon columns became apparent. The most successful
method of controlling H2S generation at that time according to EPA was by
feeding a nitrate solution. Nitrates are preferred by anaerobic bacteria
over sulfates as an oxygen source and nitrogen gas is produced instead of
sulfide gas. The annual cost of feeding nitrates in our waste stream was pro-
jected to be in the order of $140,000 - $200,000.
This represented a ten (10) to fifteen (15) percent increase in pro-
jected annual operating cost, thus necessitating a search for an alternative
odor control method.
Our thoughts centered around a toxicity approach, yet it had something
easily handled and environmentally safe to dispose of. A literature survey
indicated that an alkaline environment could inhibit metabolism enough to act
effectively as a disinfectant. Laboratory studies were undertaken to verify
that sulfide producing bacteria could be destroyed by exposure to a pH re-
lated environment. When this hypothesis was proven correct, work was ex-
panded to develop time/pH/effectiveness information. These results demon-
strated that contacting sulfur reducing bacteria for twenty-four (24) hours
at a pH greater than 11.5 would result in zero bacteria recovery. Full scale
evaluation of this method was initiated in the Fall of 1976. Initial results
demonstrated the growth rate of the bacteria removed during the filtering
process would require a disinfection procedure once every five (5) or six (6)
weeks to effectively control sulfide odors. This would have resulted in a
chemical expense of about $20,000 annually. However, since biological growth
is related to temperature, we estimated the average disinfection frequency
required to be twice that of the winter months or an annual cost of $40,000.
As we got into the summer months we found it increasingly difficult to
achieve satisfactory disinfection and realized something else would have to
be done to control sulfide odors during the warm weather period.
A modification to the system was attempted in the summer of 1978. Bio-
logical activity was allowed to occur in the filter vessels,but the filter
effluent pH was elevated to 8.5 to keep the sulfides in the soluble form. At
this point the effluent was aerated to air oxidize the sulfide to sulfate,
This modification has proven to be cost effective and generally success-
ful in controlling the sulfide odor. However, controlling the sulfide odor
has unmasked another odor which currently is unidentified. The best descrip-
tion of this odor is a low tide or dead fish smell. This "dead fish" type
odor emanates from the river for about 1/2 mile beyond the plant discharge.
The odor essentially disappears when the carbon system is bypassed.
Other major failures in the carbon adsorption system have included
surface wash shower mechanisms breaking, a pipe coupling separating on the
discharge side of one of our main filter dosing pumps, inability of an
115
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automatic flow control system to properly control the flow distribution be-
tween the individual filter units and corrosion of the filter vessels due to
an apparent problem with filter liners. The failure of surface washing
mechanisms and corrosion of filter vessels have been reported at various
other activated carbon facilities.
The carbon regeneration system has only operated on an intermittent
basis to date. Major problems exist with carbon feed control to the
reactivation furnace, excessive pump wear when moving the carbon slurry and
carbon losses within the system. Reactivated carbon quality appears to be
most sensitive to the spent carbon quality and the contact time of the carbon
in the reactivation zone. Steam feed and reactivation zone temperature do
play a part in controlling the reactivated carbon quality, but are only
effective in optimizing or fine tuning process efficiency.
Aside from the many equipment problems at the plant, the overriding
major difficulty of the facility to date has been its inability to produce an
effluent quality which satisfies discharge permit limitations. Even though
we have been able to pass the total plant flow through the adsorption system
for a relatively short period, it has been evident that the' effluent quality
would exceed the allowable BOD,, discharge for quite some time. The City is
currently under an EPA administrative order to proceed with a 201 Facilities
Plan to bring the plant into compliance with discharge permit requirements.
A Step 1 Grant application is being prepared so engineering work to bring
about compliance may proceed. In addition, the City is seeking to recoup
damages through litigation.
A significant effort has been put forth in developing sampling and
monitoring procedures that accurately reflect unit process performance. The
major factor influencing operating cost of an activated carbon treatment
system is reactivation frequency. Regenerating the carbon too frequently
increases utility and fuel consumption costs and results in excessive makeup
carbon purchase to replace the carbon lost during the reactivation process.
However, utilizing the carbon beyond a certain point makes effective reac-
tivation extremely difficult. Currently, the operating and maintenance cost
for the West Fitchburg Facility is about $375 per million gallons.
Carbon facilities treating a multiple component waste stream have not
observed removal efficiencies that approach the typical "S" type curve pre-
sented in the literature. This makes the determination of when to reactivate
carbon extremely subjective. Data generated to date on the carbon filter
BOD- reduction has shown some significant trends. The first thing we consis-
tently observe is a very high removal efficiency for the first seven (7) to
fourteen (14) days of operation with either virgin or reactivated carbon.
The removal efficiency in this time frame is in excess of 75%. The second
observation is a transition period of varying removal efficiencies which
quickly levels out at around a 60% efficiency. From this transition period
only a very gradual loss in removal efficiency is experienced, even when the
carbon has been loaded beyond what is normally accepted as exhausted. We
have measured BOD, removal efficiencies of better than 50% when the carbon it
was applied to haa an iodine value of less than 400. Generally, an iodine
number lower than 550 is considered to indicate exhaustion.
116
-------
Figure 1 is a plot removal efficiency vs. run time for a typical filter
unit at the Fitchburg Facility. The 340 million gallons treated represents
over 6 months of operation without reactivation. The carbon has adsorbed
over .5# of BOD5 per pound of carbon. Figure 2 is a graph of the filter
effluent BOD5 from the same unit over the same time period. Removal effi-
ciency does show some positive correlation with the applied load which tends
to dampen fluctuations in the effluent quality. However, the effluent qual-
ity also exhibits random fluctuations indicative of changes in the charac-
teristics of the influent organic load.
A number of hypotheses have been developed based on our observations to
date, some of which have been verified and implemented to improve plant per-
formance and reliability. Others require careful evaluation under controlled
conditions. For example, our system utilizes the activated carbon as a fil-
ter media as well as an organic adsorber. This necessitates daily backwash-
ing of the media and results in mixing the contents of the bed. Although
theoretically the bed should resettle according to particle size, the carbon
particle density has been altered somewhat by adsorbing organic material.
This raises the question of whether particle size controls the stratification
as in a sand filter, or particle density as in a mixed media filter. This
question is extremely important when a design is based on the traditional
wave theory of exhaustion.
Recent articles have reported measurements which demonstrate that selec-
tive desorption occurs in water treatment plants where carbon is utilized
for taste and odor control. It seems reasonable to assume that the same
.phenomena exists in wastewater plants using activated carbon. The impact of
desorption of effluent BOD5 and COD should be evaluated in light of the
current discharge permit program where BOD^ is generally used to determine
organic strength.
Consideration should also be given to the use of pH control to optimize
carbon adsorption efficiency, particularly on waste streams that exhibit very
consistent characteristics.
One topic that is currently receiving considerable attention is the
effect of bioactivity on process efficiency. Literature cites greatly en-
hanced carbon adsorptive capacity due to biological activity consuming
organic material adsorbed on activated carbon. This, in effect, would con-
tinuously release adsorption sites for further adsorption. Electron micro-
scope photographs, however, show numerous bacteria present during bioactivity
that are about the same diameter as many surface pores as well as a signifi-
cant amount of slime that could block adsorption sites and possibly hinder
adsorption. Two Wastewater Treatment Facilities utilizing carbon adsorption
have observed at least temporary increases in carbon removal efficiency
immediately following a procedure that effectively destroyed biological
activity.
During studies on the effectiveness of an alkaline soak for sulfide con-
trol, parallel pilot columns were operated for a three-month period. One
column was fed nitrates, one was periodically dosed and soaked with caustic,
117
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and in a third column bacterial action was allowed to occur producing sul-
fides. BOD removal efficiency for the three columns showed no statistically
significant variation. We are currently conducting studies to compare the
possible long term benefits of biologically active carbon with the potential
surface adsorption interference due to biological slime growth. Our experi-
ences to date have led us to believe that any increase in process efficiency
due to biological activity is negligible.
In addition, numerous secondary effects are observed which must be
sidered in the overall cost benefit analysis. These include increased head-
loss resulting in higher pumping costs, and corrosion of electrical gear due
to the presence of sulfides.
The chemical primary system has performed extremely well since initial
startup, the process has consistently yielded a 55% BODj. reduction, 95% sus-
pended solids removal and 95% turbidity reduction. The carbon system has
provided an average 60% reduction of the remaining BOD,, and about 70% of the
remaining suspended solids. Overall plant efficiencies of 80% BOD,, and 98%
TSS have been sustained during normal operation.
Based on experiences to date at Fitchburg and a number of other physical
chemical treatment facilities, I believe certain things have become evident:
1. Special consideration must be given to the physical and mech-
anical design problems associated with activated carbon storage
and transport.
2. The conclusions drawn from previous work concerning activated
carbon treatment technology must certainly be qualified based
on factors that were, and were not, considered during those
investigations .
3. Scale up from pilot studies to full scale must take into account
more factors than just contact time and theoretical exhaustion
rates.
4. Studies examining activated carbon treatment performance on a
single or homogeneous waste stream are not directly correlatable
to variable situations.
5. More knowledge must be generated on carbon adsorption kinetics
before it should be considered a predictable technology.
As for the future of activated carbon adsorption as a unit treatment
process, I envision the major application area to be removal of toxic organic
compounds. I believe there are numerous other applications for activated
carbon in wastewater treatment, but they are dictated by specific conditions
and the carbon utilized for a limited role in the overall treatment scheme,
If carbon adsorption is to be considered in the future for a major role
in wastewater treatment systems, major changes will be required in the way
process evaluations and facility designs are conducted. Experience has
118
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shown that questions concerning activated carbon treatment still remain to
be answered, and it will be the answers to these questions that determine
the potential for the use of activated carbon in wastewater treatment in the
future.
REFERENCES
1. "Process Design Manual for Carbon Adsorption." U.S. Environmental Pro-
tection Agency Technology Transfer, Washington, D.C., October, 1973.
2. Burt, N.E. and Taylor, J.L. "Hydrogen Sulfide Control in Activated
Carbon Filters by Caustic Disinfection." Unpublished, 1976.
3. Callahan, W.F. "Summary Report on Activated Carbon Pilot Plant at the
West Fitchburg Plant." Unpublished, 1977.
4. Directo, L.S., Chen, D. and Kugelman, I.J. "Pilot Plant Study of
Physical-Chemical Treatment." Journal WPCF, October, 1977.
5. Dallaire, G. "Carbon Treatment of Drinking Water: N.J. Plant Trying
to Get Out the Bugs." Civil Engineering, January, 1980.
6. Weber, W.J. et al. "Biological Growth on Activated Carbon: An Investi-
gation by Scanning Electron Microscopy." Environmental Science and
Technology, 12, 6 (1978).
7. Ying, W. and Weber, W.J. "Bio-Physiochemical Adsorption Model Systems
for Wastewater Treatment." Journal WPCF, November, 1979.
119
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10(h
WEST FITCHBURG WWTF
BODs REMOVAL EFFICIENCY
l-o
o
is
o
Q
in
Q
O
OQ
60-
40-
20-
50
100
150
200
250
300
350
WASTEWATER TREATED (MG)
FIGURE 1
-------
WEST FITCHBURG WWTF
CARBON FILTER EFFLUENT QUALITY
40,
30-
50
a
o
t—i
H
UJ
U
§
LT)
Q
O
oa
20-
10-
T3o
"2^0
300
WASTEWATI-R TREATED (MG)
FIGURE 2
-------
TEXTILE WASTE TREATMENT AT A
MUNICIPAL PACT* FACILITY
C. A. Pitkat, Superintendent
Water Pollution Control Facility
Vernon, Connecticut 06066
and
C. L. Berndt, Senior Systems Engineer
Zimpro Inc.
Rothschild, Wisconsin 54474
ABSTRACT
The first U.S. municipal Powdered Activated Carbon Treatment (PACT)*
facility is currently in operation at Vernon, Connecticut. The PACT process
is performing well treating a highly colored textile wastewater despite the
treatment system and plant equipment problems that have occurred in the
initial year of operation of the facility. Both a low effluent BOD_ concen-
tration (<5 mg/L) and efficient color removal have been maintained. This
paper describes the initial year of PACT operation.
INTRODUCTION
This paper describes the initial operation of the 24,500 M /day (6.5
MGD) Powdered Activated Carbon Treatment (PACT) process located in the Town
of Vernon, Connecticut. The municipal treatment facility at Vernon serves
a. residential population of approximately 30,000 people and an industrial
fraction that consists of textile dyehouse operations, metal plating, and
manufacturing industries.
Prior to 1978, wastewater treatment at Vernon consisted of primary
settling, dual trickling filters, clarification and chlorination prior to
discharge to the Hockanum River. Primary sludge solids and trickling filter
humus were anaerobically digested, chemically conditioned and landfilled.
Performance of the trickling filter plant was less than adequate due, in
part, to the dyehouse wastes. BOD^ and suspended solids removals averaged
approximately 60 to 70%. Color removal was non-existent.
In addition to its poor performance, the trickling filter was operating
near its design flow capacity.
122
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Since the receiving stream, the Hockanum River, experiences extremely
low flow periods during the summer, and the desired stream quality dictated
that plant effluent BOD levels Be less than 20 mg/1 with color discharges
controlled, it became necessary to upgrade treatment at Vernon.
Though numerous treatment systems were considered for application at
Vernon, the process selected and implemented was the PACT process ^ the tise
of powdered activated carBon in the aerator of the activated sludge process.
When Zimpro Inc. Wet Air Oxidation is applied to the PACT process for spent
carBon regeneration, the treatment is commonly referred to as, the Wastewater
Reclamation System (WRS) and is hereafter referred to as such.
DESCRIPTION OF SYSTEM
The treatment facility layout is shown in Figure 1, the treatment plant
flow scheme in Figure 2. Details of the process design are listed in TaBle
1. Raw wastewater enters the treatment facility at the preliminary treatment
area receiving coarse screening and comminution. Grit is then removed from
the waste by two parallel aerated grit chambers, washed and transported to
landfill. The raw wastewater is subsequently pumped to two 24.4 m diameter
primary clariflocculators. Though not used to date, chemical coagulation is
provided for suspended solids and pH control. Primary solids are pumped to
two gravity thickeners located adjacent to the incineration Building. Thick-
ened primary sludge at 6% to 8% solids is chemically conditioned w±th ferric
chloride and lime and dewatered to 25% solids on two rotary vacuum filters.
The dewatered sludge, presently transported to landfill, is to Be incinerated
in a 7 hearth multiple hearth furnace.
From the primary clariflocculator, the settled wastewater flows to a
6 m (20 feet) square and 4,6m (15 feet) deep scrubbing channel where the re—
generated carbon is added to the primary effluent wastewater flow. The flow
is then split between 4 aeration tanks. To supply the Biological oxygen re^
quirements coarse bubble diffusers are located along one side of each aera^
tion tank. Three 5,000 SCFM aeration blowers are provided and located within
the regeneration building. All aeration tanks can be operated in a plug flow
or complete mix mode. The aeration tanks and final clarifiers can also Be
operated in a two stage treatment mode.
Liquid cationic polymer is applied to the MLSS at each aeration tank
outlet prior to flow to the final clarifiers. Thickened clarifier underflow
from each final clarifier is removed by a rapid sludge pickup mechanism and
recycled to the inlet of the aeration tanks.
Following solids separation, the clarified water is pumped to the four
dual media filters located in the filtration building. The product water is
disinfected and discharged to the Hockanum River. Optionally, the clarifier
effluent can be passed directly to the chlorine contact chamber for disin-
fection and discharge.
The excess secondary sludge, a mixture of spent powdered activated car-
bon and biomass, is wasted from the recycle lines to the two spent carBon
gravity thickeners which are located adjacent to the regeneration Building.
-------
Figure 1. Wastewater Treatment Facility; Vernon, CT.
-------
WASTEWATER RECLAMATION SYSTEM
FLOW DIAGRAM
VERNON.CT
CHEMICAL
ADDITION
(OPTIONALl
M
Ul
AERATED
GRIT
RAW REMOVAL
WASTEWATER^
PRIMARY
CLARI-
FLOCCULATOR
GRIT TO
LANDFILL
PRIMARY
THICKENER
VACUUM
FILTRATION
FILTER CAKE TO LANDFILL-*
(OPTIONAL)
INCINERATION
ASH TO LANDFILL
CARBON
MAKE-UP
LIQUID
POLYMER
AIR
AERATION
=H>
SETTLING
^MMJ
FILTRATION
(OPTIONAL)
'PUMP
GRAVITY
THICKENER
STORAGE
TANK
PRODUCT
WATER
CI2 CONTACT
Figure 2, Flow Diagram of the Wastewater Treatment Facility; Vernon, CT.
-------
_TABLE 1 PROCESS DESIGN AND EQUIPMENT DATA; VERNON,
Primary Clariflocculator Tanks
Number
Size
Overflow Rate @ Q average
Sludge Pumps
Aeration Tanks
Number
Size
Detention @ Q average
MLSS Concentration
Secondary Clarifiers
Number
Size
Overflow Rate @ Q average
Overflow Rate @ Q peak
Return Sludge Pumps
Number
Dual Media Filters
Number
Size
Hydraulic Loading @ Q average
Media
Gravity Sludge Thickeners
Spent Carbon, Number
Size
Primary Sludge
Number
Size
Vacuum Filters
Number
Filter Area, each
Solids Loading
Incinerator
Number
Size
Hearths
Wet Air Regeneration Unit
Number
Design Flow
Feed Solids Concentration
Design Temperature
Design Pressure
24.4m X 24.4m (80 ft x 80 ft)
4.0m (12.75 ft) SWD _
1.35 m3/m2 /hr (800 gpd/ft )
3 @ 57 m /hr (250 gpm)
27.4m x 7.6m (90 ft x 25 ft) x
3.6m (12 ft) SWD
3.0 hrs
12,000 mg/L
4 Centerfeed
23m (75 ft) Diam x 4.0m
(12.75 ft) SWD
0.7 m3/m2/hr (400 gpd/ft )
1.9 m/m 7hr (1075 gpd/ft )
6 @ 360 m3/hr (1600 gpm)
4
5m x |l.{p (16 ft x 38 ft)
6.1 m /m /hr (2.5 gpm)
0.60mm sand and anthrafilt cap
9.1m (30 ft) Dia x 4.0m
(12.75 ft) SWD
12.2m (40 ft) Dia x 4.0m
(12.75 ft) SWD
2 2
35m (376?ft.)
1.7 Kg/m /hr (3.5 Ib/ft /hr)
5.1m (16 ft 9 in) O.D.
7
3.15 L/sec (50 gpm)
60 g/L
240 C (470 F)
63 Kg/cm (900 psig)
126
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Clarified overflow from the thickeners returns to the scrubbing channel
Thickener underflow is pumped to a 130 MJ (4500 ft ) mixed storage tank prior
to regeneration to allow the WAR unit to operate relatively independent of
the spent carbon thickeners.
The thickened carbon slurry is subjected to Wet Air Regeneration (WAR)
to recover the activated carbon for reuse and destroy the associated organic
solids. The WAR unit's flow scheme is shown in Figure 3. One of two_high
pressureoPumPs raises the spent carbon slurry to a pressure of approximately
56 Kg/cm2 (800 psig), pumping the slurry into the heat exchangers Each pump
is a variable flow triplex piston pump sized to provide up to a 3.8 L/sec
(60 gpm) flow.
Compressed air, provided by two of three process air compressors, is
added to the carbon slurry flow prior to the heat exchangers. One process
air compressor serves as a standby unit. The combined slurry and air mixture
passes thru heat exchangers where its temperature is raised to the desired
reactor inlet temperature of 195-205°C (380-400 F). In the system reactor
the biological solids and sorbed organics contained in the slurry are wet
oxidized. A net heat gain is realized by the oxidation reactions that take
place. The small amount of solubilization of organics that does occur is re-
turned to the aeration basins for biodegradation. Hot reactor products are
passed through the heat exchangers to recover the produced heat. The cooled
regenerated slurry is passed through a pressure reducing station and added to
the wastewater flow at the scrubbing channel. The spent air from the WAR
process is collected from the scrubbing channel and is treated prior to dis-
charge.
Two steam generators are provided in the regeneration system for use in
system start-up only.
WASTEWATER CHARACTERISTICS
The Vernon treatment facility was designed on the basis of the flow
data and wastewater concentrations as shown in Table 2. The wastewater con-
tains, besides typical domestic wastewater, industrial wastes from a syn-
thetic textile processing facility. Other industrial wastes include those
from the manufacture of electrical controls and equipment, manufacture of
electrical components such as printed circuit boards, aluminum and foil anod-
izing, and wastewaters from the production of water and auto filters.
TABLE 2 DESIGN CRITERIA; VERNON, CT.
Daily Flow, M3/Day = 24,600 (6,5 MGD)
Peak Flow, M /Day = 66,300 (17.5 MGD)
Influent BOD , mg/L = 150 to 300
Effluent BOD;?, mg/L = < 20
Influent SS, mg/L = 150 to 400
Effluent SS, mg/L = < 10
Influent Color, APHA = 50 to 600
Effluent Color, APHA = Colorless
127
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IV)
00
WET AIR REGENERATION SYSTEM
FLOW DIAGRAM
SPENT
CARBON
THICKENER
©
VERNON, CT
STORAGE
TANK
e
HEAT
EXCHANGERS
REACTOR
STEAM
GENERATORS
(START-UP)
REACTOR
SLOWDOWN
POT
PROCESS
AIR
COMPRESSORS
SCRUBBING CHANNEL
Figure 3. Flow Diagram of the Wet Air Regeneration System; Vernon, CT.
-------
The textile dyehouse operation is primarily engaged in nylon fabric
dyeing and finishing with a much smaller emphasis on other synthetic fibers
such as polyester, polyester cotton blends, acetate and cellulosic fabrics.
Acid dye-stuffs at neutral pH levels are principally used for the nylon fab-
ric processing along with various dyeing assistants and finishing chemicals.
The principal acid dyestuffs include various orange, red, blue, navy and
black dyes as listed in Table 3. Small amounts of disperse and direct dye-
stuffs are also used. Primary dyeing assistants and finishing chemicals used
are presented in Table 4. The use of these dyes and finishing chemicals re-
sults in an alkaline wastewater with a significant BOD5, high COD level and
high color level. Much variability is noted in the waste since the product
manufacture varies greatly.
, TABLE 3 TYPICAL DYESTUFF
Nylanthrene Orange BGN
Nylanthrene Red B2B
Nylanthrene Navy LFWG
Altcofast Black N5X
Nylomine Blue AG
Supernylite Scarlet B
TABLE 4 DYEING ASSISTANTS AND FINISHES
Dyeing Assistants
Acetic Acid
Ammonia
Caustic Soda
Monosodium Phosphate
Trisodium Phosphate
Sodium Chloride
Xylol
Finishes
Zepel RN
Disodium Phosphate
Enegen (detergent)
Triamine (detergent)
Melamine Formaldehyde
Analysis of the other industrial wastes show that varous contaminants
are present at high levels in specific wastes. Organic contaminants, ammonia
nitrogen and COD, are present at high concentrations. Metals including alumi-
num, iron and particularly copper are present at very high concentrations in
some industrial discharges. Other contaminants including cyanide, cadmium,
nickel, zinc, and chromium are present at low levels. The industrial wastes
all exhibit low BOD /COD ratio's indicative of the industrial nature of the
wastes.
The Vernon treatment facility also receives raw septage on a five day/
week basis. Approximately 120,000 to 150,000 gallons of septage per month
are received on a Monday thru Friday basis and discharged directly to the
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plant influent sewer. A septage holding and metering facility is installed
but has not operated as yet.
The influent pH levels to the Vernon facility vary from approximately
six to ten. However, short-term raw waste pH fluctuations from three to
twelve units have occasionally occurred. The effluent pH levels average
approximately 7.0.
Wastewater Sampling and Analytical Procedures
Wastewater analytical data reported in this paper were performed accord-
ing to Standard Methods and Zimpro Inc. analytical methods (1) (2). Adapta-
tion of conventional analytical procedures have been made to accurately re-
port the low carbonaceous BOD,, and true color measurements obtained. The
partitioning of the mixed liquor suspended solids into the volatile biomass
and volatile activated carbon concentrations were obtained by a nitric acid
digestion technique (2).
Wastewater sampling is conducted daily in accordance with the current
regulatory requirements for the treatment facility.
TREATMENT SYSTEM OPERATION AS ACTIVATED SLUDGE
Primary Treatment
The primary treatment system was placed into service in July 1978.
Performance indicated that 50 percent suspended solids removal from the raw
wastewater could be expected without chemical addition. Though testing with
ferric chloride up to application levels of 80 mg/L as FeCl_ was done, chem-
ical addition is not used in present plant operation.
Chemical conditioning of the primary sludge with 2-5% ferric chloride
and 10-15% lime on a dry solids basis has resulted in vacuum filter cake
solids levels of approximately 20-25%.
By November 1978 most unit processes other than the rapid sand filter
were completed, tested, and ready for start-up.
Secondary Treatment System
Since the process schemes of the WRS and activated sludge system are
identical, it was possible to operate the treatment facility in an activated
sludge mode prior to the addition of activated carbon. With equipment run-
in complete, activated sludge operation was begun in mid-November 1978. A
major purpose for the activated sludge operation was to begin training the
operations staff in treatment system control and ease the later conversion to
Wastewater Reclamation. Excess biological solids produced in the secondary
system during the activated sludge mode, however, were wasted from the final
clarifiers and disposed of with the primary waste sludge.
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By mid-December reasonable steady-state operation was obtained. The
activated sludge process was operated in a single stage mode at mixed liquor
suspended solids concentrations ranging from 2000 to 3000 mg/L and a sludge
age (based on aeration solids) of two to three days. The effluent dual media
filters were not available for operation during this period as feed and back-
wash piping remained to be completed.
The performance of the activated sludge system during stable treatment
is shown in Table 5. The primary influent BOD5> COD and suspended solids
concentrations of 78 mg/L, 556 mg/L, and 146 mg/L were reduced to approxi-
mately 33 mg/L, 237 mg/L, and 40 mg/L in the clarifier effluent; a turbidity
of 188 Nephelometric Turbidity Units (NTU) was reduced to 20 NTU, Consider-
able foaming occured in the aeration basin as expected; at initial start-up
color removal exhibited by the activated sludge process was better than that
obtained by trickling filter treatment, yet was not satisfactory. Near the
later part of this period of operation filamentous bacterial growth was noted
in the system which began to affect overall plant operation and performance.
At this time the entire system was converted to the WRS.
TABLE 5 ACTIVATED SLUDGE SYSTEM PERFORMANCE
Vernon, Connecticut
Parameter Raw Influent Clarifier Effluent
BOD , mg/L
COD, mg/L
SS, mg/L
Turbidity, NTU
78
556
146
188
33
237
40
20
*Primary and waste activated sludges were chemically con-
ditioned.
TREATMENT SYSTEM OPERATION AS WRS
Primary Treatment
The preliminary and primary treatment systems have remained in opera-
tion to date without chemical addition for pH or suspended solids control.
In March 1979, an accumulation of primary sludge solids occurred due to
vacuum filter problems. Due to the inability to vacuum filter the sludge
solids and storage of the sludge in the primary clariflocculators, an ex-
tremely large volume of septic primary sludge (approximately 1/2 of the
primary sludge inventory) overflowed to the secondary system. These sludge
solids accumulated in the WRS mixed liquor and were processed along with the
excess spent carbon slurry wasted to the Wet Air Regeneration unit. An ex-
cess of floatables and scum also reached the secondary system. This condi-
tion did not result in a deterioration of effluent quality.
Another problem that resulted in frequent process equipment maintenance
is construction debris. This problem persisted throughout the initial year
131
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of plant operation. The primary clariflocculators required draw-down and
cleaning to remove plastic sheets and pipe wrapping. Similarly, plastics
plugged the secondary system scum handling pumps resulting in damage. On
numerous occasions, final clarifier draw down and cleaning was necessary to
remove wood and other construction debris. During the initial dual media
effluent filter testing, construction debris and accumulated crud was washed
into the filter beds requiring extensive filter cleaning. In operation of
the Wet Air Regeneration unit, frequent plugging of the inlet strainer oc-
curred at times. To minimize this problem', a dual basket strainer was in-r
stalled to replace the original single basket strainer.
Secondary Treatment
Liquid Treatment
The secondary treatment system was converted from an activated sludge
mode to the Wastewater Reclamation system during February 1979, with the
addition of a considerable portion of the powdered activated carbon charge
to the secondary system. The volatile carbon concentration in the aeration-
contact basins was brought up to about one-half of the design concentration.
Processing of all excess spent carbon slurry solids in the Wet Air Regenera-
tion unit began at this time. Improved reductions in effluent BOD , COD and
color levels were obtained in the WRS mode of operation.
The operating conditions during the initial 12 months of WRS operation
(March 1, 1979 to March 1, 1980) are presented in Table 6. Several comments
are appropriate. The MLSS and volatile carbon concentrations, while ade-
quate to provide a high level of treatment, are lower than the expected
design levels. Examination of the WRS performance at a lower volatile car-
bon level was of interest during the initial treatment plant operation. In
addition, lower MLSS levels were considered appropriate during initial opera-
tion, anticipating the operator training requirements and construction activ^
ities to be completed.
TABLE 6 WASTEWATER RECLAMATION SYSTEM OPERATING DATA
Vernon, Connecticut
Daily Flow, M3/Day 3 = 12,730 (3.36 MGD)
Maximum Daily Flow, M /Day = 26,630 (7.03 MGD)
Maximum Sustained Peak Flow,
M /Day = 40,900 (10.8 MGD)
Aeration Tank Dissolved
Oxygen, Mg/L = Q.5 - 2.0
MLSS, mg/L = 11,700
ML Ash, mg/L = 4,500
Volatile Carbon, mg/L = 4,300
Biomass, mg/L = 2.900
The volatile activated carbon concentration maintained in the aeration-
contact tanks during this period of operation was approximately 4,300 mg/L.
The activated carbon supplied for the initial charge and to replace operating
132
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losses was Hydrodarco H. A plot of the monthly average mixed liquor sus-
pended solids concentration is shown in Figure 4.
The suspended ash fraction of the mixed liquor ranges from 30 to 40 per-
cent and results from the carryover of suspended ash from the primary clari-
flocculators. Control of the MLSS ash fraction is obtained via the regenera-
tion reactor blowdown of inert ash. Reactor blowdown, which occurs during
normal steady-state operation of the unit, can be increased or decreased in
proportion to the average mixed liquor suspended ash level. The inert ash
blown down during regeneration is returned to the grit chamber for disposal
with the grit.
The average daily raw wastewater flow rate to the treatment facility
during the initial year of operation was 12,730 M3/day (3.36 MGD) with a
peak sustained flow of 40,900 M^/day (10.80 MGD). The maximum daily raw
wastewater flow treated was 26,630 M /day (7.03 MGD), approximately a 2:1
maximum day to average day flow ratio.
The average secondary clarifier recycle suspended solids concentration
during this period was 31,000 mg/L with an approximate maximum of 60,000 mg/L.
Several important events are noteworthy in the Vernon WRS operation and
must be considered when examining the treatment system performance. First,
the dual media effluent filter was not operational, except for intermittent
periods, until mid-July 1979 due to problems with the motor controls on the
filter feed pumps.
The liquid polymer feed system was ineffectual to June 1979 because the
polymer piping to the aeration-contact tanks was damaged. Thereafter,
carrier/dilution water flow was added to the stock polymer discharge lines
to enhance mixing and distribution to the MLSS flow to the secondary clari-
fiers. The actual liquid cationic polymer addition rates to the WRS range
from approximately 0.5 to 1.5 mg/L.
To reinforce piping anchors on the aeration tankage air diffuser piping,
each of the four aeration basins was emptied during August and September,
1979. Each repair required about one week to complete.
During November 1979, operation of the Wet Air Regeneration unit was
interrupted for nearly a two-week period to complete installation of the
spent carbon storage tank and transfer/feed pumps.
A problem throughout this period has been loss of prime of the secon-
dary clarifier recycle pumps and subsequent loss of return sludge capability.
Minor modifications were made to allow automatic gas venting from the pump
discharge piping in November 1979. Permanent modifications are planned to
improve the recycle pump performance and reliability. Until then, higher-
than-normal pump rates must be used to overcome loss of prime.
133
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40
35
30
25
g/L 20
15
IO
O
MLSS
WASTEWATER RECLAMATION SYSTEM
VERNON. CONNECTICUT
O MIXED LIQUOR SUSPENDED SOLIDS
-CARBON ADDED TO WWTP
J I I I I L
_L
J L
J _ I I _ I
I I
JL
4O
35
30
25
20 g/L
15
IO
DEC JAN. FEB. MAR. APR. MAY JIM JUL. AUG. SEP. OCT. NOV. DEC. JAN FEB. MAR. APR. MAY.
1979 1980
Figure 4, Mixed Liquor Suspended Solids Concentration, WRS; Vernon, CT,
-------
The installation of the excess sludge wasting pumps are not complete,
requiring sludge wasting directly from the secondary clarifier recycle. Due
to the high wasting rates, large variations in clarifier sludge blanket
levels occur. Excessive solids loading rates on the spent carbon thickeners
have also occurred.
Solids Processing
The Wet Air Regeneration system has been on-line in support of the
secondary wastewater treatment during the entire period of plant operation.
The regeneration system operating conditions are presented in Table 7.
TABLE 7 WET AIR REGENERATION SYSTEM OPERATING DATA
Vernon, Connecticut
Feed Solids to Regeneration, g/1 =83.7
Regeneration Temperature, °C2 = 232 ± 5 (450 ± 10 F)
Regeneration Pressure, Kg/cm = 49-53 (700-750 psig)
Flow Rate, L/sec = 1.5-3.0 (25-50 gpm)
Operating Schedule, hrs/day x
days/wk = 12 x 5
The spent carbon/biomass feed slurry concentration to the regeneration
unit averaged approximately 84 g/L and ranged from 60 g/L to slightly greater
than 100 g/L suspended solids during this period. This level is somewhat
greater than the 60 g/L feed concentration anticipated but allows operation
of the regeneration unit at a lower high pressure pump rate than the 3.0
L/sec (50 gpm) nominal design flow rate.
During normal operation of the Wet Air Regeneration unit and during
daily start-up of the unit, supplemental fuel addition (steam) is not re-
quired; autothermal regeneration is consistently obtained. Due to the heat
retention properties of the regeneration unit and the capability of bottling
the hot reactor at system pressure, steam addition for start-up is necessary
only when the unit has been idle for several days. When operated daily, the
WAR unit is simply brought on-line by unbottling the regeneration reactor,
adding thickened carbon slurry flow to the system, and adding air. Provided
that the initial start is gradual, the regeneration system begins auto-
thermal operation immediately and is fully on-line in approximately one hour.
PERFORMANCE OF WRS
The performance of the pure biological activated sludge system was less
than adequate in treating the Vernon combined domestic and industrial waste-
water. The inability to treat the highly colored waste is illustrated in
Figure 5. With the addition of a small amount of powdered activated carbon
to the secondary treatment system, a significant improvement in clarifier
effluent quality was obtained.
135
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ar-.;., *;
-------
Representative wastewater samples from the present WRS operation are
shown in Figure 6, after one year of treatment plant operation. The improve-
ment in color removal is evident. An effluent true color of 20 to 40 APHA
is obtained, whereas the raw wastewater color is 150 to 500 APHA and up to
5000 APHA apparent color.
Regeneration of the excess spent carbon slurry from the WRS provided
continual reuse of carbon and maintained a high level of waste treatment.
Though severe treatment conditions have occurred at times and stressed the
WRS operation, performance has been stable. The overall performance results
for this twelve-month period, March 1979 to March 1980, are shown in Table 8.
All wastewater samples collected are reported in the numerical averages. The
average primary influent raw wastewater carbonaceous BOD5, COD, suspended
solids and turbidity concentrations were 200 mg/L, 840 mg/L, 450 mg/L and
148 NTU, respectively. The average effluent carbonaceous 6005, COD, sus-
pended solids and turbidity concentrations were 4 mg/L, 73 mg/L, 8 mg/L and
10 NTU, respectively. Prior to mid-July 1979, the effluent results reported
are secondary clarifier overflow data. The subsequent performance data is
the dual media filter effluent data.
TABLE 8 WASTEWATER RECLAMATION SYSTEM PERFORMANCE
Vernon, Connecticut
Parameter
BOD5, mg/L
COD, mg/L
SS, mg/L
Turbidity, NTU
Raw Influent
200
840
450
148
Effluent*
4
73
8
10
*Dual media effluent filter placed on-line in mid-July, 1979.
Perhaps a better perspective of the WRS performance is obtained by ob-
serving the monthly average BOD^ data for this period of WRS operation. A
monthly average 8005 plot is illustrated in Figure 7. The results show that
a consistently low effluent BODr has been obtained.
Optimization of Treatment
Since the treatment system at Vernon is still in a semi-start-up mode
of operation, optimization of treatment has not been conducted. Upon com-
pletion of the plant modifications, this work can be initiated.
Savings in operating costs and optimum performance will be obtained
with better manpower utilization and scheduling. Selection of the optimum
treatment system operating conditions will also assist. WRS performance at
higher aerator mixed liquor carbon concentrations will also be examined.
In summary, the Wastewater Reclamation System at Vernon, Connecticut
has performed well to date. Improved performance is expected as optimiza-
tion of treatment is obtained.
137
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Filter Effluent, Clarifier Effluent, and Wastewater Influent;
WRS, Vernon, CT.
138
-------
5OO
45O
400
350
3OO
250
mg/L
2OO
150
100
50
O
BOD5
WASTEWATER RECLAMATION SYSTEM
VERNON, CONNECTICUT
O PRIMARY INFLUENT
A EFFLUENT
iOO
450
400
350
3OO
NOTE: EFFLUENT FILTER ON-LINE IN MID-JULY
SEE TABLE 5 h-CARBON ADDED TO WWTP
I I i. A- j, A &..
I 1 I
25O
mg/L
2OO
150
100
5O
0
DEC. JAN. FEB. MAR. APR. MAY. JUN. JUL. AUG. SER OCT. NOV. DEC. JAN. FEB. MAR. APR. MAY
1979 I960
Figure 7. Monthly Average BODc, WRS; Vernon, CT.
-------
REFERENCES
1. "Standard Methods for the Examination of Water and Wastewater,"
American Public Health Association, New York, 1975.
2. Barr, J. W., "Biomass and Activated Carbon in Carbon Mixed Liquors;
Nitric Acid Digestion Technique," Inter-office correspondence.
140
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PB*3-142257
REVIEW OF THE USE OF OZONE FOR IMPROVING COMBINED
MUNICIPAL/INDUSTRIAL WASTEWATER TREATMENT
R. G. Rice, Ph.D.
Jacobs Engineering Group
1725 K Street, N.W., Suite 608
Washington, D.C. 20006
ABSTRACT
Ozone has been developed for the treatment of sewage since the early
1970's and primarily in the United States. As of today, there are 11 opera-
tional sewage treatment plants in the USA using ozonation, another 23 are
under construction and another 5 are in design. Most of these plants utilize
ozone for disinfection. Full scale plant operational data and data from
pilot plant testing upon which full scale plant designs have been developed
are discussed. In plants providing tertiary treated wastewaters, including
filtration of secondary effluents, when the wastewater does not contain sig-
nificant levels of industrial wastes, the average absorbed ozone dosage re-
quired to achieve a disinfection level of 200 fecal coliforms/100 mL is 4 to
8 mg/L. However, when significant amounts of industrial wastes are present
in the initial sewage, then absorbed ozone dosages can run as high as 10 to
15 mg/L. To attain the more rigid disinfection level of 2.2 total coliforms/
100 mL using municipal wastewaters not containing industrial components re-
quires 15 to 20 mg/L absorbed ozone dosage with filtered nitrified secondary
effluent and 35 to 40 mg/L of filtered secondary effluent. Other uses of
ozone in treating combined municipal/industrial wastewaters include oxidation
of organic materials prior to passage through granular activated carbon.
This technique appears to provide significant savings in costs associated
with operation of granular activated carbon adsorbers.
INTRODUCTION
Since the early 1970's, investigators in the United States have been
studying the use of ozonation for disinfecting sewage treatment plant
effluents. Many of these studies have been conducted on municipal waste-
waters which contain significant amounts of industrial wastes. A few studies
have been reported in which ozone has been used for treatment purposes other
than disinfection.
Ozone has been used for the disinfection of drinking water supplies in
the city of Nice, France, since 1906. Today there are well over 1,000 other
drinking water treatment plants throughout the world using ozonation for
141
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disinfection and many other purposes (1). Most of these plants are in
Europe, as might be expected because it is in Europe that the use of ozone
has been pioneered for water treatment. Table 1 lists the primary purposes
for which ozone is utilized today in treating drinking water. Most of these
uses involve the strong oxidizing ability of ozone.
TABLE 1 APPLICATIONS OF OZONE IN WATER TREATMENT (2)
Bacterial Disinfection
Viral Inactivation
Oxidation of Soluble Iron and/or Manganese
Decomplexing Organically-bound Manganese (oxidation)
Color Removal (oxidation)
Taste Removal (oxidation)
Odor Removal (oxidation)
Algae Removal (oxidation)
Removal of Organics (oxidation) such as pesticides, detergents & phenols
Removal of Cyanides (oxidation)
Suspended Solids Removal (oxidation)
Increase Biodegradability of Dissolved Organics (oxidation) for Biological
Removal of Ammonia & Dissolved Organics Upon Passage Through Filtration
or GAG Adsorption Media
Europeans do not disinfect sewage, thus use of ozonation techniques for
sewage treatment is sparse in Europe as of this time. On the other hand, in
the USA, where sewage disinfection is practiced, it was recognized during the
late 1960's that chlorination for this purpose was causing sometimes severe
environmental insults (3). Consequently, beginning in the late 1960's, a
considerable amount of research has been conducted in American sewage treat-
ment plants and institutional laboratories on the use of ozone as an alterna-
tive sewage disinfectant to chlorine. This amount of activity has culminated
in 11 currently operational sewage treatment plants using ozone, mostly for
disinfection. In addition, another 23 American sewage treatment plants are
under construction which include ozonation, and at least another 5 plants are
being designed with ozonation. Wastewaters entering some of these municipal
treatment plants contain significant amounts of industrial wastes which, in
turn, can affect the treatment requirements necessary for successful dis-
infection with ozone. Discussion of this point will be the major theme of
this paper.
The use of ozonation for treating industrial wastewater contaminants to-
day in commercial size plants includes such applications as disinfection of
waters used for aquacultural purposes, destruction of cyanides in metal
finishing effluents, oxidation of organic materials in wastewaters from
caprolactam and textiles manufacturing plants, destruction of phenols in and
to polish refinery wastewaters, recycle and reuse of spent iron cyanide
photographic bleaches and for the recycle of automobile washwaters (14).
Many industrial waste components are present in municipal wastewaters and can
be treated by means of ozone.
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In Table 2 are listed some of the more significant milestones in ozone
technology, as related to water and wastewater treatment, since it was dis-
covered in 1785.
TABI
,E 2 MILESTONES IN OZONE TECHNOLOGY — WATER & WASTEWATER TREATMENT
1785 Van Marum noted characteristic odor near electrostatic machine
1801 Cruickshank noted same odor in anode gas during water electrolysis
1840 Schonbein named the substance "OZONE"
1886 de Meritens - first experiments with ozone as a germicide
1893 Oudshoorn, Holland - first drinking water treatment plant to use
ozonation
1906 Nice, France - ozone for drinking water disinfection — ozone has
been used continuously
1940 Whiting, Indiana - first USA drinking water plant to use ozone
(for taste & odor)
1957 Ozone installed at Boeing Co., Wichita, Kansas, to destroy cyanide
in industrial wastewaters
1961 Dusseldorf, Federal Republic of Germany - first use of granular
activated carbon following ozonation (drinking water)
1963 (64) First use of ozone in Swiss (German) swimming pools
1975 Indiantown, Florida - first sewage treatment plant to use ozone
(disinfection)
1977 First commercial use of UV/ozone combination to destroy metal
cyanide complexes in metal finishing wastewaters
PROPERTIES OF OZONE
Ozone is an unstable gas which boils at minus 112 C (-112 C) at atmo-
spheric pressure and has a characteristic penetrating odor5 readily detectable
at concentrations as low as 0.01 to 0.05 ppm. By considering the relation-
ships between Henry's Law constants, the solubilities of oxygen (present in
air) and ozone in water and the concentrations of ozone and oxygen in air,
VENOSA & OPATKEN (4) have shown that the solubility of ozone in water is
about 13 times that of oxygen, over the temperature range of 0°C to 30°C.
Additionally, ozone is a powerful oxidant, having an oxidation potential
of 2.07 volts in alkaline solution, which is second to that of fluorine. As
a result, ozone is capable of oxidizing a great many organic and inorganic
species which are found in waters and wastewaters. On the other hand, be-
cause ozone is such a powerful oxidant, it is not selective when it functions
as an oxidant. This means that when solutions contain easily oxidizable com-
ponents (BOD, nitrite, free cyanide, bacteria, many constituents which exert
a chemical oxygen demand, etc.), all of these materials will be oxidized,
assuming that sufficient ozone is provided to the solution to satisfy all
immediate oxidant demands.
143
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At the relatively low concentrations of ozone produced by industrial
generation equipment (1 to 3% in air; 2 to 6% in oxygen) no explosion hazard
exists, but mixtures of ozone concentrated to 15 to 20% or higher in air can
be explosive. Currently available ozone generators cannot generate suffi-
ciently high concentrations of ozone in air or in oxygen to be explosive. On
the other hand, ozone is a toxic gas, and unnecessary exposures can be detri-
mental to humans. Care must be taken in designing ozonation systems to uti-
lize proper materials of construction, to guard against leakages of ozone
into plant atmospheres and to provide ambient plant air ozone monitoring
equipment and safety shut-down features in the event of ozone leakages.
In aqueous solution, ozone is relatively unstable, having a half-life of
about 165 minutes in distilled water at ambient temperatures (6), If oxi-
dant demanding materials are present in solution, the half-life of ozone in
such solutions will be even shorter. Therefore, ozone applied in small
dosages will not provide a long-lasting disinfecting residual in drinking
water or in wastewater.
On the other hand, ozone in air (especially under dry conditions) is
much more stable than in water. The half-life of ozone in the ambient atmo-
sphere has been determined by the U.S. Environmental Protection Agency to be
on the order of 12 hours. In dried air, the stability of ozone is even
greater. Thus, ozone can be produced from dry air or oxygen in a water or
wastewater treatment plant, then piped considerable distances to the contact-
ors with no fear of losing the product by decomposition back to oxygen.
Before proceeding further, it is important for the newcomer to ozone
technology to understand the definitions of some fundamental terms used in
discussing the application of ozone so that the data presented in the litera-
ture regarding ozonation in aqueous media can be interpreted properly. First
of all, the application of the partially soluble ozone to water is effected,
in nearly all cases, by passing ozonized air or oxygen through the water in
the form of fine bubbles. During the period of time that these ozonized gas
bubbles are in contact with the aqueous medium, much of the ozone contained
by the gas will be transferred from the gaseous bubble to solution, where the
ozone then can react with the soluble or suspended components. However, not
all of the ozone applied is transferred from the gas into solution phase.
The amount of ozone which does transfer into solution will depend upon the
flow rate of ozonized gas through the water, the size of the gas bubbles,
concentration of ozone in the gas phase, and the flow rate of water being
treated relative to the flow rate of ozonized air or oxygen. Thus it is
apparent that some untransferred ozone will be present in the head space of
the contactor chamber above the solution.
VENOSA & OPATKEN (4) have developed and STOVER & JARNIS (5) have pre-
sented the relationships between applied ozone dosage, absorbed or utilized
ozone dosage, and ozone transfer efficiency in the following manners:
The applied ozone dosage (D), in mg of ozone per L of liquid, is deter-
mined by the equation:
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D = Y^/QJ
where: Y = mg of ozone/L of carrier gas
Q = flow rate of carrier gas, L/min
G
Q = liquid flow rate, L/min
.L
The ozone transfer efficiency, %TE, is defined by the equation;
%TE = [YI - YZ]/[YI] x 100%
where: Y = mg ozone/L in gas phase leaving the ozone contactor
The absorbed ozone dosage. A, in mg of ozone absorbed/L of liquid, is
defined by the equation:
A = D x %TE
Substituting for D and %TE and simplifying gives:
A = Y1(QG/QL)[Y1 - Y2]/[Y1], and
A= oyQ^- YZ)
Therefore, as pointed out by STOVER & JARNIS (5), those principal fac-
tors which affect the performance of ozone in disinfecting municipal (or com-
bined municipal/industrial) wastewaters (water quality, % ozone transfer
efficiency and absorbed ozone dosage) become key issues in evaluating the
feasibility and economics of designing such systems and should be established
for each specific ozone application, rather than relying upon generalities
in the published literature.
Unfortunately, much of the early literature regarding the application
of ozone to disinfection of municipal wastewaters as well as to the treatment
of industrial and combined municipal/industrial wastewaters refers only to
the applied ozone dosages, without specifying flow rates of gas and liquid
^G^l} or the amount of ozone remaining in contactor off-gases (Y ). In the
balance of this presentation we shall discuss only those projects In which
all of the above parameters were reported.
HISTORY OF OZONE IN MUNICIPAL WASTEWATER TREATMENT
It was recognized in the late 1960's that the use of chlorination for
disinfecting sewage treatment plant effluents was producing toxic effects on
aquatic life in receiving bodies of water (3). As a result, demonstrations
of the use of ozonation were conducted, some of these sponsored by the U.S.
Environmental Protection Agency.
Wynn et al. (6) conducted an extensive pilot plant study of ozonation
for tertiary treatment of several different types of secondary effluents at
the Washington, B.C. Blue Plains treatment plant. NEBEL et_ al,
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(7) conducted an extensive pilot plant study at Louisville, Kentucky on an
oxygen-activated sludge effluent. ROSEN et_ _al. (8) described pilot plant
programs conducted at Fairfax, Virginia; Dallas, Texas; St. Paul, Minnesota
and Hendersonville, Tennessee. Many other pilot plant studies have been con-
ducted and most of these have been reported in the proceedings of meetings of
the International Ozone Association held since 1973 (9-12). Results of some
of these studies, particularly those involving combined municipal/industrial
wastewaters, will be discussed later in this presentation.
In November, 1975, the 0.5 mgd sewage treatment plant at Indiantown,
Florida, began disinfecting its effluent with ozone. This was the first full
scale application for ozone in sewage treatment. The Indiantown plant has
been operating satisfactorily ever since. Ozone dosages of 7.5 mg/L attain
a fecal coliform level of less than 70/100 mL (13) in wastewaters which do
not contain industrial contributions.
As of March 1980, there are 11 U.S. sewage treatment plants operating
on full-scale with ozonation — these plants are listed in Table 3. At the
same time, an additional 23 U.S. are under construction incorporating ozone—
these are listed in Table 4. Finally, Table 5 lists 5 additional plants
which are being designed and in which ozone has been incorporated into the
treatment process. As details of successful and cost-effective operation of
these plants become available to the engineering community, even more exten-
sive use of ozone in sewage treatment can be anticipated in the future.
MUNICIPAL WASTEWATER TREATMENT WITH OZONE
Table 6 lists pertinent data concerning some of the full scale municipal
wastewater treatment plants using ozone for disinfection and which do not
contain significant amounts of industrial wastes in their influent waters.
In this table we are concerned with the use of ozone for disinfection, the
type of wastewater treatment before ozonation, the amount of industrial waste
contained in the influent to the sewage treatment plant (none), and the ab-
sorbed dosage of ozone required to attain the desired level of disinfection.
146
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_TABLE 3 OPERATIONAL USA SEWAGE TREATMENT PLANTS USING OZONE (MARCHLJ1980^
Location
Indiantown, FL
Woodlands, TX
Upper Thompson Sanita-
tion District, CO
Chino Basin, CA*
Palo Alto, CA**
Harriman, NY
Collegeville, MN
Mahoning County, Oh***
Hunter Highlands, NY
Cotter Gasville, AR
Springfield, MO***
System
Type
Air/03
Air/03
Air/03
Air/03
Air/03
Air/03
Air/03
°2/03
Air/3
Air/03
o2/o3
Start-Up
Date
1975
1976
1977
1978
1978
1978
1978
1978
1978
1978
1978
Average
Flow, MGD
0.5
1.5
IP
.5
5.0
4.0
— — —
0.22
4.0
< 1
1
35
All plants except Chino Basin and Palo Alto use ozone for disinfection.
* Chino Basin uses ozone to remove suspended solids.
** Palo Alto uses ozone prior to GAG adsorption and filtration.
*** Plants using oxygen-activated sludge process.
It will be apparent from the data of Table 6 that the absorbed ozone
dosages required to attain the disinfection level of 200 fecal coliforms/100
mL are in the range of 4 to 8 mg/L. The Hunter Highlands, New York plant is
attaining a disinfection level of zero fecal coliforms/100 mL, but utilizes a
very clean, tertiary treated effluent.
On the other hand, it is equally important to observe that at all of the
operating plants rather extensive tertiary and/or advanced wastewater treat-
ment is practiced before ozonation. This results in rather clean effluents,
which should contain much lower levels of suspended solids (10 mg/L or less)
than would effluents processed by activated sludge or oxygen activated sludge
alone (about 30 mg/L). Such high quality effluents may be the reason that
ozone dosages required to attain 200 fecal coliforms/100 mL disinfection
levels are relatively low (4 to 8 mg/L). For example, it has been shown by
SPROUL et al. (18) that encasement or adsorption of enteric bacteria and
viruses in fecal material and HEp-2 cells protects these microorganisms from
concentrations of ozone that would normally destroy or inactivate them in the
unadsorbed, free state. Thus a basic principle in consideration of ozone for
wastewater disinfection would appear to be the provision of an effluent con-
taining the lowest suspended solids concentration as practicable or cost-
effective under the local circumstances.
147
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TABLE 4. USA SEWAGE TREATMENT PLANTS USING OZONE—UNDER CONSTRUCTION,
MARCH, 1980
Location
Oak Ridge, NY
Norton AFB, CA
Carmel, NY
Potomac Heights, ME)
Murphr eesboro , TN*
Casper, WY
Pensacola, FL*
Hercules, CA
Marion, NY
Brookings , SD
Concord, NC*
Delaware County, OH
Frankfort, KY
Granby, CO
Yap hank, NY
Hagerstown, MD*
Holland, MI*
Ocean City, MD*
Olympia, WA*
Rocky Mount, NC*
Madisonville, KY*
Indianapolis, IN
(Richmond)
Indianapolis, IN
(Belmont)
Feed
Gas
Air
Air
Air
Air
Oxygen
Air
Oxygen
Air
Air
Air
Oxygen
Air
Air
Air
Air
Oxygen
Oxygen
Oxygen
Oxygen
Oxygen
Oxygen
Oxygen
Oxygen
Estimated
Start-up
1980
1980
19&0
1980
1980
1980
1980
1980
1980
1980
1980
1980
1980
1980
1980
1981
1981
1981
1981
1981
1980
1981
1981
Average
Flow, MGD
0.12
0.25
1.
0.2
8
<1
20
0.4
<1
6
25
1.5
7
<1
0.12
8
5
12
14 (35 peak)
14
5
125
125
All plants will use ozone for disinfection.
* Plants using oxygen-activated sludge process.
TABLE 5. USA SEWAGE TREATMENT PLANTS USING
Location
Cleveland, OH
(Westerly)**
Tacoma, WA*
Vale, CO
Henrico County, VA*
Lynn , MA*
Feed
Gas
Oxygen
Oxygen
Air
Oxygen
Oxygen
OZONE - IN
Estimated
Bid Date
1980
1981
1980
1981
1981
DESIGN, (MARCH, 1980)
Average
Flow, MGD
50
60
8
25
*Plants using oxygen-activated sludge process.
** A physical/chemical
(ozone-enhanced
process with ozonation followed
BAG).
by GAG adsorption
148
-------
On the other hand, BHARGAVA (20), in discussing the evaluation of ozona-
tion for the new Murphreesboro, TN plant, concluded that if only 25% more
ozone is required to disinfect the oxygen activated sludge treated plant
effluent without filtration, then filtration before ozonation would not be
cost-effective. The Murphreesboro plant is scheduled to start operating
shortly, and operating data to confirm this point should be available later
in the year.
All of the remaining plants listed in Table 6 and scheduled to begin
operating in 1980, initially will apply 4 to 10 mg/L of absorbed ozone
dosages to attain disinfection levels of 200 fecal coliforms/100 mL, It is
interesting that the plants at Frankfort, KY (30) and Delaware County, OH
(19) appear to have specified ozone dosages without conducting pilot plant
testing at either site. Both influent wastewaters contain very little, if
any, industrial contaminants, so that the primary concern in being able to
attain satisfactory disinfection with ozonation would appear to be with the
suspended solids content of the treated wastewaters. Performance data for
these two plants are anxiously awaited to confirm or deny the dosages of
ozone which actually will be required. Delaware County, OH has installed 10
mg/L ozone dosage capability, but may be able to attain their disinfection
objective with considerably less.
In Table 7 are listed four oxygen activated sludge municipal wastewater
treatment plants which are (Springfield, MO) or will be (Olympia, WA and the
two Indianapolis, IN plants) using ozone for disinfection and whose influent
wastewaters also contain significant industrial waste loadings. At Indianap-
olis some 40% of the flow and 70% of the strength are comprised of light
industrial wastes (pharmaceutical, food and starch manufacturing, bottle
manufacturing)(21).
'' 149
-------
t_n
O
TABLE 6. OZONE DISINFECTION OF MUNICIPAL WASTEWATERS AT OPERATING PLANTS OR PLANTS UNDER CONSTRUCTION ^
industrial
Location components
Indiantown, FL
Woodlands, TX
Upper Thompson
Sanitation
District, CO
Mahoning County,
OH
Hunter High-
lands, NY
Oak Ridge, NY
Murphreesboro,
TN
none
none
none
none
none
none
small ;
enters
in slugs
treatment
before ozonation
Imhof tank, trick-
ling filter, coag-
latlon (polyelect-
rolyte, laminar
filtration.
biological, lime,
coagulation, C02.
Act. sludge, nit-
rification, tri-
media filtration.
2-step oxygen ac-
ivated sludge w/
lime in 2nd step,
clarif . , floccn. ,
recarbn., dual
media filtrn.
extnd. aeration,
Neptune micro-
floe filtration
screen, RBC, Nep-
tune microfloc
filtration
oxygen act. si . w/
2-stage nitrif. +
filtration
avg. flow
rate, mgd
0.5
1.5
1.5
4
80,000
gpd
0.12
8
av. absorbed
ozone, mg/L
7.5
8
6
6
1
30-40
6
plant
startup
date
1975
1976
1977
(15)
1978
1978
1980
4/1980
Remarks
attains 70 fecal coli-
forms/100 mL (13).
obtains 200 fecal coli-
forms/100 mL.
obtains 200 fecal coli-
forms/100 mL. Ozone
transfer effic. 50-60%.
obtains 200 fecal coli-
forms/100 mL (16).
attains zero fecal coli-
forms/100 mL
designed to obtain zero
fecal col i forms/ 100 mL
to obtain 200 fecal
col i forms/1 00 mL.
No pilot studies done.
-------
TABLE 6. (Continued)
industrial
Location components
Pensacola, FL
Frankfort, KY
Delaware County,
OH
Brookings, SD
Granby, CO
Madisonville, KY
none
v. little
none
none
none
?
treatment
before ozonation
oxygen act. si . ;
filtration
extended aeration
oxidation ditch ;
no filtration
act. sludge
act. sludge
?
oxygen act. si.
avg. flow
rate, mgd
20
7
1.5
6
<1
5
av. absorbed
ozone, mg/L
5
4
(30)
10
(max)
7
6-8
6.5
plant
startup
date
5/1980
4/1980
1980
late
1980
1980
4/1980
Remarks
to attain 200 fecal
coliforms/100 mL.
to attain 200 fecal
coliforms/100 mL. No
pilot testing conducted.
to attain 200 fecal
coliforms/100 mL. No
pilot testing done.
to attain 200 fecal
coliforms/100 mL
to attain 200 fecal
coliforms/100 mL
to attain 200 fecal
coliforms/100 mL
-------
Ui
ho
TABLE 7. OZONE DISINFECTION OF MUNICIPAL WASTEWATERS CONTAINING INDUSTRIAL COMPONENTS J
Location
Springfield,
OH
Olympia, WA
Indianapolis,
IN
industrial
components
food proces-
ing, light
indl. (milk,
pharmaceut.
60% brewing
pharmaceut. ,
food procsg.
starch mfg.,
bottle mfg.
treatment
primary settlg. ,
oxygen act. si . ,
air nitrif. act.
si . , tri -media
filtrn.
oxygen act. si.
without filtrn.
trickling filt. ,
oxygen act. si . ,
nitrification,
filtration.
avg. flow av. absorbed
35
14 (35 pk)
2 plants,
125 mgd ea.
10
10*
5
* Dosage of 10 mg/L specified without pilot plant studies.
plant
startup
date
1978
1981
1981
Remarks
attains 200 fecal coli-
forms/100 mL w/3% 03 in
oxygen.
to attain 200 fecal coli-
forms/100 mL.
to attain 200 fecal coli-
forms/100 mL.
-------
The Springfield plant wastewater receives nitrification and tri-media
filtration after oxygen activated sludge, and still requires an absorbed
ozone dosage of 10 mg/L to attain the disinfection target of 200 fecal coli-
forms/100 mL. Without filtration, some 2 to 3 times this dosage would have
been required (22). On the other hand, the two Indianapolis plant waste-
waters will receive nitrification and filtration after oxygen activated
sludge, but these plants are designed to receive only 5 mg/L of absorbed
ozone dosages. These dosage levels have been confirmed during two different
pilot plant studies (23).
At the Olympia, WA plant, about 60% of the sewage to be treated comes
from the local brewing company. These wastes are high in readily degradable
BOD , which are expected to be treated to acceptable levels by the oxygen
activated sludge process. Rather high levels of ozone (10 mg/L absorbed
dosage) have been designed into the plant to attain disinfection. On the
other hand, no pilot plant testing has been reported on this wastewater (24).
It remains to be seen whether disinfection of this wastewater can be attained
with less than 10 mg/L ozone dosage, without the need for filtration.'before
ozonation.
PILOT PLANT OZONATION STUDIES ON COMBINED MUNICIPAL/INDUSTRIAL WASTEWATERS
LOUISVILLE, KENTUCKY (7)
Sewage influent to the Fort Southworth plant contains 60% industrial
waste loading, which includes dyestuffs and highly variable COD levels. The
pilot plant study involved passing the available primary treated effluent
through an oxygen activated sludge pilot plant unit. An applied ozone dosage
of 15 mg/L (non-filtered effluent) was required to attain a 200 fecal coli-
form/100 mL disinfection level.
The 15 mg/L of absorbed ozone dosage provided the additional perfor-
mances listed in Table 8, including nearly 100% inactivation of viruses, 99+
removal of total coliform, fecal coliform and fecal streptococci bacteria
and 70% and 29% reduction in turbidity and COD levels, respectively. In
addition, the ozonized effluent produced no noticeable harmful effects on
native fish populations, whereas non-ozonated secondary effluent was toxic
in a test study.
DALTON, GEORGIA (25)
More than 200 carpet-producing and related firms provide 90% of the
wastewater loading to the Dalton, GA treatment plant, which provides primary
then secondary treatment. The effluent from this plant, however, contains
high color and COD levels (an average of 275 APHA units and 150 mg/L of COD,
respectively). A pilot plant study was conducted to determine the efficacy
of treating this unfiltered effluent with ozone to lower the color from the
average 275 to 30 APHA units. Such treatment was found to require absorbed
ozone dosages of 45 mg/L. Equivalent color removal also could be obtained
by means of granular activated carbon adsorption, requiring 780 mg/L dosages
of GAC.
153
-------
TABLE 8. OZONATION TEST RESULTS—LOUISVILLE, KY (32; 7)
Average absorbed ozone dosage
Effluent type
15 mg/L
Oxygen activated sludge
Effluent analyses
total coliforms
fecal coliforms
fecal streptococci
viral inactivation
average turbidity removal
average COD removal
average color removal
average BOD removal
average TOG removal
500/100 mL
103/100 mL
9/100 mL
nearly 100% after 5 minutes
ozone contact time & residual
of 0.05 mg/L
707-
29%
79%
15%
15% to 20%
Table 9 shows the results obtained by application of 45 mg/L of ozone
to this combined municipal/industrial wastewater. Not only was the color
objective attained, but also significant reduction in levels of COD (40%),
suspended solids (85%), biphenyl content (51%), anionic detergent content
(92%), fecal coliforms (100%) and total coliforms (99.99%). In addition,
inorganic carbon levels increased 67% (showing that considerable organic
carbon was converted into CO^) and dissolved oxygen increased from 2 to 8.5
mg/L.
WYOMING, MICHIGAN (26)
Wastewater influent to this plant contains 35% to 45% light industrial
wastes from metal plating, dairy products and other commercial establishments.
Significant quantities of phenolic compounds also are present in the waste-
water (31). A pilot plant study was performed to compare the disinfecting
performance of ozone, chlorine (with and without dechlorination) and bromine
chloride, then to determine the toxicity of the disinfected effluents to
aquatic life (26).
Absorbed ozone dosages averaging 7.4 mg/L gave fecal coliform levels
averaging 68/100 mL from a filtered trickling filter effluent during most of
the study. True color was lowered upon ozonation from 86 to 36 Pt-Co units,
but COD was unaffected. The ozonized effluents did not show detrimental
effects upon survival of fathead minnows. Acute toxicity tests conducted on
fathead minnows showed less mortality with ozonized effluents than with
effluents treated with the other disinfectants, but only the ozonized
effluent was filtered before disinfection. It was also observed that ozone
dosage levels required to attain disinfection were more dependent upon the
effluent quality than were the other disinfectants.
154
-------
PROBLEMS :
«• regenerate CAC every 3O-4O days
• sulfidie odors
* erratic TOC valaes
* erratic disinfectant demands
Figure! Westerly plant, Cleveland,
Ohio —original design.
155
-------
TABLE 9. TREATMENT OF DALTON, GA UNFILTERED EFFLUENT WITH 45 MG/L OZONE
Parameter
Color
COD
BOD
DO
Organic Carbon
Inorganic Carbon
Suspended Solids
Biphenyl
Anionic Detergents
Fecal Colifonns
Total Coliforms
pH
Initial
275 APHA
156 mg/L
21 mg/L
2 mg/L
53 mg/L
3 mg/L
20 mg/L
1.85 mg/L
0.6 mg/L
8,000/100 mL
850,000/100 mL
6.8
Final
30 APHA
94 mg/L
21 mg/L
8.5 mg/L
54 mg/L
5 mg/L
3 mg/L
0.90 mg/L
0.05 mg/L
0/100 mL
2,500/100 mL
7.1
% Change
- 89%
- 40%
0%
+ 325%
+ 2%
+ 67%
- 85%
- 51%
- 92%
-100%
- 99.99%
+ 4%
CLEVELAND, OHIO (WESTERLY PLANT)
At Cleveland's 50 mgd Westerly plant, influent wastewaters contain
about 45% of wastes from chemical plants, a steel mill, slaughterhouses and
paint companies. The Westerly sewage currently is treated by a physical-
chemical process which includes granular activated carbon adsorption as a
late step for removal of dissolved organics prior to disinfection. The flow
scheme for this treatment plant, as originally placed in operation, is given
in Figure 1. Data reported were determined on a 30 gpm pilot plant unit
which was operated 24 hours/day, 7 days/week (33). Originally, ozone was
studied for providing disinfection to the GAG column effluent.
During early stages of operation of this pilot plant, however, it be-
came apparent that the effluent characteristics varied greatly from day to
day. High iron levels in the wastewater influent required high lime dosages.
In addition, incoming levels of phosphorus approached the detection level,
negating the effects of pH control for phosphorus removal. In turn, these
variations caused decreases in capture of suspended materials in the clari-
fier (up to 38% increases in clarifier effluent during periods of high iron
conditions). Also, the quality of the sludge changed considerably in terms
of volatile matter contained, and a significant amount of iron was re-
solubilized during recarbonation.
Additionally, GAC adsorption failed to consistently produce an effluent
which met the treatment objectives for BOD and COD, even at low cumulative
loadings. Sulfidic odors developed in the GAC adsorber, caused by anaerobic
microorganisms which evolved in the low dissolved oxygen environment, and the
ozone demand of the GAC effluents to attain the disinfection level of 200
fecal coliforms/100 mL varied widely. Resolubilized iron was reduced and
adsorbed on the GAC, and interfered with restoration of adsorption capacity
of the GAC upon thermal regeneration. A noticeable reduction in both soluble
iron and soluble COD took place during ozonation 90% of the time, but the
total TOC remained unchanged, indicating that the organic materials present
were being changed chemically, rather than being oxidized to C0_ and water.
156
-------
en
E
c
0)
o
O
o
o
»
preozonation
9101112131415161718192°212223
months in operation
o>
c
TO
(0
0)
O
<
O
Q
O
O
(0
3
E
Figure 2. Performance of GAC pilot plant unit with
and without preozonation - Cleveland.
-------
Oi
00
lime
polymer
raw
sewage
flocculator
Cl
I disinfection
CO-
sludge
GAG
adsorber
pressure
filter
Figure 3. Modified treatment process at Cleveland, Westerly plant.
-------
In attempts to correct these problems, ozonation was moved from after
GAG adsorption to after recarbonation, but before the pressure filtration
step. This immediately elevated the dissolved oxygen levels in the ozonized,
recarbonated wastewater. As a result, biological growths became aerobic and
the sulfidic odors disappeared from the GAG column. Performance of the GAG
column became quite consistent and disinfectant demands became constant.
Details of the changes made to the Westerly pilot plant process and their
effects have been published by GUIRGUIS et al. (27) .
Based upon these successful pilot plant results, ozonation has been
designed into the full scale Westerly treatment plant as a chemical oxidant
(not for disinfection) before the GAG adsorption step at applied dosages of
about 8 mg/L step for several reasons. First, the presence of dissolved
oxygen in the GAG influent will prevent anaerobic biological growths in the
GAG columns, and therefore prevent the generation of hydrogen sulfide in the
system. Second, the higher molecular weight polymers which are not readily
adsorbed by the GAG are cracked into lower molecular weight fragments which
are better adsorbed. Thirdly, a major proportion of the biorefractory or-
ganic materials is partially oxidized upon ozonation, producing organic
materials which are more easily biodegraded. These partially oxidized or-
ganics are biodegraded in the GAG adsorption columns. Finally, soluble iron
will be oxidized to the ferric state, in which it will hydrolyze and be fil-
tered out of the system before coming into contact with the GAG adsorber,
prolonging the life of the GAG.
The biologically enhanced granular activated carbon medium has been
found to have a prolonged useful life before thermal reactivation is required.
In pilot plant studies, GUIRGUIS, _et_ _al. (27) showed that the GAG column
without a prece ding ozonation step was unable to remove BOD sufficiently to
meet the EPA discharge standards nor to remove COD to consistent levels. In
addition, the GAG had to be thermally reactivated every 30 days. By contrast,
when sand filtration then GAG adsorption followed an ozonation step (5 to 6
mg/1), not only did the column effluent meet the BOD discharge limitation,
but the COD content became constant and the GAG was used for 21 months with-
out having to be reactivated. When ozonation was discontinued, immediate
breakthrough of organics (COD) was observed; however when ozonation was re-
started, the GAG column performance quickly returned to its steady state
condition of meeting the required discharge standards. This behavior is
shown in Figure 2 (28).
Based on these results, Cleveland is designing 6,700 Ibs/day of ozone
generation capacity (from oxygen) into the Westerly plant prior to GAG ad-
sorption. Chlorine disinfection still is practiced after GAG adsorption, be-
cause it is cost-effective over the 10 mg/L of ozone which would be required
(28). The process to be installed is shown schematically in Figure 3.
The Palo Alto, California wastewater treatment plant has incorporated
ozonation prior to GAG adsorption (29), which has been operating since 1978,
whereas the ozone/GAC process will not be operating in the full-scale
Westerly plant until 1981. Data on the performance of the system as well as
cost savings in GAG reactivation from both of these sewage treatment plants
are anxiously awaited.
159
-------
MARLBOROUGH, MASSACHUSETTS (5)
Although the sewage treated with ozone at this location is primarily
municipal, there are several aspects of this plant which are of significance
to this discussion. At Marlborough, a pilot plant study has been conducted
to evaluate ozone as a wastewater disinfectant to attain the very stringent
2.2 total coliforms/100 mL disinfection standard, currently required by the
California State Department of Health for non-restricted recreational uses
of wastewater.
Secondary effluent and nitrified secondary effluent were treated with
ozone with and without prior dual media filtration. Absorbed ozone doses of
between 2 and 35 mg/L were applied to these effluents at contactor hydraulic
reaction times of 1 to 10 minutes, yielding total effluent residual oxidant
concentrations of 0.4 to 8.0 mg/L. Absorbed ozone doses necessary to achieve
less than 2.2 total coliforms/100 mL and 70 total coliforms/100 mL are given
in Table 10. Filtered nitrified effluent required absorbed ozone dosages of
15-20 and 5-10 mg/L to attain less than 2.2 and 70 total coliforms/100 mL,
respectively; filtered secondary effluent required 35-40 and 15-20 mg/L of
ozone to attain less than 2.2 and 70 total coliforms/mL, respectively. Fecal
coliforms were never detected in the ozonated effluents which contained less
than 2.2 total coliforms/100 mL.
TABLE 10. ABSORBED OZONE DOSAGES REQUIRED FOR DISINFECTION- AT MARLBOROUGH, MA.
Effluent Absorbed Ozone Dose, mg/L
to attain less than 2.2 total coliforms/100 mL
Filtered Nitrified 15 to 20
Filtered Secondary 35 to 40
to attain 70 total coliforms/100 mL
Filtered Nitrified 5 to 10
Filtered Secondary 15 to 20
COSTS OF OZONE TREATMENT
Costs should be determined on a site-specific basis and compared with
the costs of alternative treatment processes considered for attaining the
specific treatment objective(s). It should also be borne in mind that chemi-
cals added for one purpose, say disinfection, can result in other benefits or
detriments. For example, the use of chlorine for wastewater disinfection
now is known to produce chlorinated by-products and/or residual chlorine
levels which must be removed in some regions by a dechlorination step, which
will add to the treatment costs. On the other hand, ozonation for wastewater
disinfection has been shown to lower color levels, COD, suspended solids,
inactive viruses and increase the level of dissolved oxygen. However, if
the wastewater must be filtered before ozonation, these costs also must be
considered as a consequence of selecting ozone as the treatment process.
160
-------
In most cost comparisons which have been made to date, ozonation is re-
ported to be about as costly as chlorination/dechlorination, when the waste-
water requires 4 to 8 mg/L to attain the required level of disinfection.
In more specific terms, however, recent studies of VENOSA & OPATKEN(4),
and performance data from some of the operating wastewater and drinking water
treatment plants currently using ozone provide the most meaningful data to
the design engineer.
Based on pilot plant studies at EPA's Municipal Environmental Research
Laboratory in Cincinnati it has been shown (4) that the major cost (36%) of
ozone disinfection of wastewater is amortization of fixed capital investment.
The power cost to generate ozone comprised 17% of the total cost, assuming
30/kWh for the cost of electricity in 1979. Operating labor (0.5 man-year)
comprised another 16% of the total. Assuming an absorbed ozone dosage of 5
mg/L and 85% ozone transfer efficiency, VENOSA & OPATKEN (4) calculated that
the total cost of ozone disinfection at a 1.3 mgd treatment plant amounts to
110/1,000 gallons. Scaling up to a 10 mgd plant would lower amortization
costs 40% and operating labor costs by 80%; thus the total cost of ozone
disinfection would drop to 4.30/1,000 gallons at this level of use.
During the early phases of operation of the Upper Thompson Sanitation
District's 1.5 mgd wastewater treatment plant (during which time the plant
operated at an average rate of 0.7 mgd), treatment costs for ozonation were
approximately 100/1,000 gallons (34). However, in a later report, RAKNESS &
HEGG (15) showed that even though the transfer efficiency of the ozone con-
tactors at this plant are only 50% to 60%, ozonation costs to attain less
than 200 fecal coliforms/100 mL are about 7.50/1,000 gallons. If the ozone
transfer efficiency could be increased to 90%, then ozonation costs at the
Upper Thompson Sanitation District could approach 5 to 60/1,000 gallons.
Using cost data developed by EPA (4), overall costs per mg/L of absorbed
ozone dose equate to 2.2o at a 1.3 mgd plant and 0.860 at a 10 mgd plant
(assumptions: 85% ozone transfer efficiency and 3o/kWh electricity cost).
Operating data at the 1.5 mgd Upper Thompson Sanitation District show costs
on the same basis to be 1.50, with an ozone transfer efficiency of only 50%
to 60%. This figure would approach 1.00 at 90% to 95% ozone transfer
efficiency.
In early 1979, the new 18 mgd Monroe, Michigan drinking water treatment
plant started operating using ozone for taste and odor control (35). During
the first 6 months of operation, an average of 1.63 mg/L of absorbed ozone
dosage was used and the average ozone transfer efficiency was 96%. The
costs for treating Monroe's drinking water with ozone were reported (35) to
be 0.6360/1,000 gallons, or 0.39C/mg/L of absorbed ozone dose, generated in
air (electricity cost: 3.1o/kWh).
Costs were estimated for treating the Dalton GA combined municipal/
industrial wastewaters with ozone (at a dosage of 45 mg/1) and with granular
activated carbon, to attain the specified color level in the treated waters
(25). Pertinent data are given in Table 10.
161
-------
TABLE 10. PROJECTED COST DATA FOR TREATING DALTON, GA WASTEWATERS (25)
Cost Factor
Ibs/day required
total capital required
amortization (7%; 20 yrs.)
annual operation & maintenance
total costs over 20 years
Ozone
4,500
$1185 MM
$237,860
$296,495
$10.7 MM
GAG
780
$11.2 MM
$1.06 MM
$29,893
$21.8 MM
Assumptions: 45 mg/L of ozone required to attain color level
flow rate: 12 mgd
GAG cost: 50C/lb; 5% lost on regeneration
GAG regeneration cost: 8
-------
• oxidize iron
• provide aerobic conditions in dual media filters & GAG adsorbers
• increase operating lifetime of GAG adsorbers before reactivation
2) Ozone is being used on full scale in United States municipal wastewater
treatment plants, primarily for disinfection, at 11 currently operational
plants. Another 23 plants are under construction and an additional 5 are in
design, all of which will incorporate ozone treatment,
3) Disinfection of secondary treated and filtered wastewaters with ozone
can attain a fecal coliform level of 200/100 ml at 4 to 8 mg/L absorbed
ozone dosages.
4) If wastewaters contain significant amounts of industrial wastes, the
ozone demands to attain comparable disinfection can increase from 4-8 mg/1 to
as high as 15 mg/L.
5) The more stringent disinfection level of 2.2 total coliforms/100 mL can
be attained with absorbed ozone dosages of 15 to 20 mg/L (filtered nitrified
secondary effluents) or 35 to 40 mg/L (filtered secondary effluents).
6) Ozone treatment of Dalton, GA combined municipal/industrial wastewater
(90% from carpet producing plants) on pilot plant scale was shown to be more
cost-effective than GAG adsorption for color removal over a 20 year period.
7) Ozonized wastewaters have not shown toxic effects to indigenous aquatic
species.
8) Costs of ozone treatment of wastewaters range from 1.5C to 2.2
-------
4. Venosa, A.D. & E.J. Opatken, Ozone Disinfection - State of the Art.
Presented at Pre-Conference Workshop on Wastewater Disinfection, 52nd
Annual Water Pollution Control Federation Conf., Houston, Texas, Oct.
7, 1979.
5. Stover, E.L. & R.N. Jarnis, Obtaining High Level Wastewater Disinfection
With Ozone: Water Quality Considerations. Presented at 52nd Annual
Water Pollution Control Federation Conf., Houston, Texas, Oct. 1979.
6. Wynn, C.S., B.S. Kirk & R. McNabney. Pilot Plant for Tertiary Treat-
ment of Wastewater With Ozone. EPA Report No. R2-73-146, U.S. Environ-
mental Protection Agency, Washington, D.C., 1973. 231 pp.
7. Nebel, C., R.D. Gottschling, R.L. Hutchinson, T.J. McBride, D.M. Taylor,
J.L. Pavoni, M.E. Tittlebaum, H.E. Spencer & M. Fleischmann. Ozone
Disinfection of Industrial-Municipal Secondary Effluents. J. Water
Poll. Control Fed. 45:2493, 1973.
8. Rosen, H.M., F.E. Lowther & R.G. Clark. Disinfection of Municipal
Secondary-Tertiary Effluents With Ozone: Five Recent Pilot Plant
Studies. In: Proc. First Intl. Symposium on Ozone for Water & Waste-
water Treatment, Washington, D.C. Intl. Ozone Assoc., Cleveland, Ohio,
1975, pp. 425-435.
9. Rice, R.G. & M.E. Browning, Editors. Proc. First Intl. Symposium on
Ozone for Water & Wastewater Treatment, Washington, D.C. Intl. Ozone
Assoc., Cleveland, Ohio, 1975. 910 pp.
10. Rice, R.G., P- Pichet & M.A. Vincent, Editors. Proc. Sec. Intl.
Symposium on Ozone Technology, Montreal, Canada. Intl. Ozone Assoc.,
Cleveland, Ohio, 1976. 727 pp.
11. Fochtman, E.G., R.G. Rice & M.E. Browning, Editors. Forum on Ozone
Technology, Chicago, 111. Intl. Ozone Assoc., Cleveland, Ohio, 1977.
435 pp.
12. Blogoslawski, W.J. & R.G. Rice, Editors. Aquatic Applications of
Ozone, Boston, Mass. Intl. Ozone Assoc., Cleveland, Ohio, 1975.
226 pp.
13. Novak, F. Two Years of Ozone Disinfection of Wastewater at Indiantown,
Florida. Presented at Seminar on Current Status of Wastewater Treat-
ment and Disinfection With Ozone, Cincinnati, Ohio, Sept. 1977. Intl.
Ozone Assoc., Cleveland, Ohio.
14. Rice, R.G. & M.E. Browning. Ozone For Industrial Water and Wastewater
Treatment, A Literature Survey. Final Report, EPA Grant No. R-803357,
in press. U.S. Environmental Protection Agency, Ada, Oklahoma, 1980.
15. Rakness, K.L. & B.A. Hegg. Full Scale Ozone Disinfection of Wastewater
at the Upper Thompson Sanitation District AWT Facility. Presented at
164
-------
Pre-Conference Workshop on Wastewater Disinfection, 52nd Annual Water
Pollution Control Federation Conf., Houston, Texas, Oct. 7, 1979.
16. Jain, J.S., N.L. Presecan & M. Fitas. Field-Scale Evaluation of Waste-
water Disinfection by Ozone Generated From Oxygen. In: Proc. Natl.
Symposium on Progress in Wastewater Disinfection Technology, Cincinnati,
Ohio, Sept. 18-20, 1978. EPA Report 600/9-79-018, U.S. Environmental
Protection Agency, Cincinnati, Ohio, 1979'. pp. 198-209.
17. Grissom, C.F. Planning Decisions in Selecting Wastewater Effluent
Disinfection for the Olentangy Environmental Control Center. In: Proc.
Natl. Symposium on Progress in Wastewater Disinfection Technology,
op. cit., pp. 258-262.
18. Sproul, O.J., C.E. Buck, M.A. Emerson, D. Boyce, D. Walsh & D. Howser.
Effect of Particulates on Ozone Disinfection of Bacteria and Viruses in
Water. EPA Report No. 600/2-79-089, U.S. Environmental Protection
Agency, Cincinnati, Ohio, 1979. 76 pp.
19. Hoff, J.C. The Relationship of Turbidity to Disinfection of Potable
Water. In: Evaluation of the Microbiology Standards for Drinking
Water, C. Hendricks, Ed., EPA Report 570/9-78-OOC, 1978.
20. Bhargava, P. Ozone Disinfection of Pure Oxygen Activated Sludge Using
Unique Partial Recycle System. Presented at 52nd Annual Conference,
Water Pollution Control Federation, Houston, Texas, Oct. 1979.
21. Robson, C.M., Dept. of Public Works, City of Indianapolis, Indiana,
1980. Private Communication.
22. Shifrin, W.G. & P.F. Johnson. Ozonation Takes a Giant Step, Water &
Wastes Engineering, March 1978. pp. 50-53. Also, Shifrin, W.G.,
Consoer, Townsend & Associates Ltd., Consulting Engineers, Chicago,
111., 1980. Private Communication.
23. Horsley, E., C.M. Robson & R.E. Riemer, Wastewater Ozonation at India-
napolis, Indiana. Presented at Symposium on Advanced Ozone Technology,
Toronto, Ontario, Canada, Nov. 1977. Intl. Ozone Assoc., Cleveland,
Ohio.
24. Allen, R.K. & V.C. Oblas. Plant to Disinfect Wastewater With Ozone.
Water & Sewage Works, July, 1978. pp. 48-53.
25. Nebel, C. & L. Stuber. Ozone Decolorization of Secondary Dye-Laden
Effluents. In: Proc. Sec. Intl. Symp. on Ozone Technology, Montreal,
Canada, 1975. Intl. Ozone Assoc., Cleveland, Ohio, 1976. pp. 336-358.
26. Ward, R.W., R.D. Griffin & G.M. DeGraeve. Disinfection Efficiency and
Residual Toxicity of Several Wastewater Disinfectants. Vol. II *-
Wyoming, Michigan. EPA Report No. 600/2-77-203, U.S. Environmental
Protection Agency, Cincinnati, Ohio, 1977. 107 pp.
165
-------
27. Guirguis, W.A., T. Cooper, J. Harris & A. Ungar. Improved Performance
of Activated Carbon by Pre^-Ozonation. J. Water Poll. Control Fed.
50(2)-.308-320, 1978.
28. Hanna, Y.A. Application of Ozone as a Carbon Pretreatment Step at
Cleveland's Westerly Plant. Presented at Seminar on Current Status of
Wastewater Treatment & Disinfection with Ozone, Cincinnati, Ohio, Sept.
15, 1977. Intl. Ozone Assoc., Cleveland, Ohio.
29. Jenks, J.H. & B.L. Harrison. Multi-Feature Reclamation Project Accom-
plishes Multi-Objectives. Water & Wastes Engineering, Nov. 1977.
30. Perrich, J.R. & D.G. Derrick. Design Philosophy for an Ozonation
Wastewater Disinfection System. Presented at 51st Natl. Water Pollution
Control Federation Conference, Anaheim, Calif., Oct. 4, 1978.
31. Chambers, C.C. U.S. Environmental Protection Agency, Cincinnati, Ohio,
1972. Private Communication.
32. Pavoni, J.L., M.W. Tenney, M.E. Tittlebaum, B.F. Maloy & T.L. Kochert.
The Consultant's Viewpoint on Alternate Disinfectants. In: Proc. Natl.
Symposium on Progress in Wastewater Disinfection Technology, op. cit.,
pp. 263-268.
33. Guirguis, W.A., J.P. Harris & P.B. Melnyk. The Negative Impact of
Industrial Waste on Physical-Chemical Treatment. In: Proc. 31st Indl.
Waste Conf., Purdue Univ., Lafayette, Ind., May4-6, 1979. Ann Arbor
Science Publishers Inc., Ann Arbor, Mich. pp. 753-763.
34. Rakness, K.L. & B.A. Hegg. Field Scale Evaluation of Wastewater Dis-
infection by Ozone Generated From Air. In: Proc. Natl. Symposium on
Progress in Wastewater Disinfection Technology, op. cit., pp. 174-197.
35. LePage, W.L. A Plant Operator's View of Ozonation. In: Proc. Seminar
on The Design and Operation of Drinking Water Facilities Using Ozone or
Chlorine Dioxide, Waltham, Mass., June 4-5, 1979. New England Water
Works Assoc., Dedham, Mass.
166
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THE USE OF SOLAR ENERGY FOR. COMBINED
MUNICIPAL-INDUSTRIAL WASTEWATER TREATMENT
A. J. Acher*
Utah Water Research Laboratory
Utah State University
Logan, UT 84322
ABSTRACT
The material presented represents three years of ongoing research on a
new method for using solar energy for municipal and industrial wastewater
treatment. This research seeks to develop economical methods of disinfec-
tion and detoxification of wastewaters which would result in the reuse of
effluents for crop irrigation.
Aerated municipal or industrial wastewaters containing dye-sensitizers
were exposed to solar irradiation for various periods of time. The influence
of the solar energy, absorbed by these sensitizers in the visible range, on
the organic matter and anionic surfactants in secondary effluents was checked
by determining the COD and MBAS values of treated wastewater.
The disinfection potential of this method was followed by bacteriologi-
cal analyses of running water or secondary effluents, previously contaminated
or enriched, respectively, with laboratory cultures of E. aoli, bacterio-
phages (coliphage X and Fa) and polio virus (type L-Sc 1).
The influence of this photooxidative method was also studied on
eutrophic algae present in the Lake of Galilee. It was found that the con-
ditions under which disinfection proceeds also support algicidal processes,
causing lethal damage to algal cultures.
Further investigations on stable pesticides (uracil derivatives) in
surface water or industrial wastewater showed that such a method can also be
used for detoxifying pesticides in these waters.
INTRODUCTION
The reuse of effluents for crop irrigation requires that they not
constitute any ecological hazard for people working in the irrigated fields
*0n sabbatical leave from the Volcani Center, Institute of Soils and Water,
Bet Dagan, Israel.
167
-------
or handling and consuming the agricultural products, or for crop growth and
soil properties. Such a requirement can be fulfilled by disinfection and
detoxification of the wastewater effluents.
The material presented represents three years of a multidisciplinary
ongoing research effort on a new method for using solar energy for municipal
and industrial wastewater treatment. It deals -with the influence of sunlight
irradiation on sensitized waters containing different organic pollutants
such as: bichromate oxidizable organic matter (COD), anionic surfactants
(MBAS), microorganisms (E. aoli, algae, polio virus, bacteriophages) and
phytotoxic organic substances (pesticides).
Dye-Sensitized Photooxidation Reactions
These chemical reactions are responsible for the oxidative processes
which take place in surface waters exposed to solar radiation. They consist
of the combined action of visible light and molecular oxygen (02) dissolved
in water upon organic matter (OM) through the intermediary of an appropriate
photosensitizer (5). The S (methylene blue, rose bengal, chlorophyll ribo-
flavin, humic acid, fulvic acid, etc.) is an organic molecule having a spe-
cial electronic structure which enables it to absorb, and then to transfer,
some of the light radiated energy. The S is added to the aerated and light
exposed effluents and its absorbed energy (S*} is made available to the oxi-
dation of OM. Either one or both of the following mechanisms can operate in
aerobic photosensitized oxidations (1):
1. Primary interaction of the electronically excited S* is with OM to
generate reactive, short-lived intermediates which subsequently react
with 02:
S + h\> ->• S* (i)
S* + OM ->• transient specia ->2 oxidation products + S (ii)
(transient specia = free radicals, ion pairs, etc.)
2. The presence of 02 will compete successfully with OM on receiving the
excitation energy from S*. The addition of this energy to 02 changes
its ground electronic state (triplet state, 3E^'02l to the first excited
singlet state (Ihg0z) which has a higher energy by 22.5 kcalmole"1.
When more energy is imparted to 02, another electronic state is formed
(1Zgr02) which corresponds to a level of 37.5 kcalmole"1 above the 3Z^02.
From the properties of singlet oxygen (exceedingly short lifetimes of
1Z^02) it seems likely that only 1A^02 is important in solution
photooxidations:
S* + 3lg02 + S + Ikg02 Ciii)
1Ag'02 + OM ->• oxidation products Civ)
In both mechanisms the sensitizer is regenerated and undergoes hundreds of
cycles so that only minute amounts of it are required.
168
-------
In view of the diversity of OM present in wastewaters, it is very
difficult to decide which mechanism operates in the present process. The
presence of singlet oxygen in natural waters was proven a few years ago C2)
and it is well known that it oxidizes unsaturated organic compounds (UC) to
peroxides. The subsequent thermal and photochemical decomposition of these
peroxides can further initiate free radical oxidation reactions which will
also affect saturated compounds (R'H) found in wastewaters:
+ UC •* ROOR -»• 2RO (v)
RO + R'H -> ROH + R' • (vi)
R'- + 02 ->• ROO, etc. (vii)
As a result of the above reactions, vital biological components (proteins,
lipids, polysaccharides) undergo oxidative degradations and, consequently,
biological development in the treated waters is inhibited. Such photosen-
sitized reactions, also referred to as "photodynamic action," were known a
long time ago (3-5) and have been extensively studied with regard to their
use in laboratory syntheses or oxidative degradation of various naturally
occurring and synthetic substances. This research overlooks the possibili-
ties of using sunlight and the above reactions for developing new methods of
purifying wastewaters which eventually will be reused for crop irrigation.
RESULTS AMD DISCUSSION
The effect of sunlight irradiation on waters containing sensitizers
and different organic pollutants will be presented and discussed.
The Effect of Photochemical Treatment of Waters on COD and MBAS Values
Samples of effluents of circulated oxidation ponds of municipal sewage
containing methylene blue (MB) were exposed to sunlight in graduated glass
cylinders (250 m£) under continuous aeration (6). After the exposure, the
MB was removed from the effluent by precipitation with bentonite clay (B),
employing a ratio of 8:1, B:MB. The supernatants were analyzed for chemical
oxygen demand (COD) and methylene blue active substances (MBAS) content and
compared to blank experiments. Figure 1 shows the effect of MB concentration
on COD and MBAS values after 6 h of irradiation at 195Q±50viEm~2s":1.
The best results were obtained at a concentration of 12 mg MBA"1. At this
concentration and 6 h of irradiation, the initial COD and MBAS values were
reduced by more than 70 percent and 90 percent, respectively. The reason
why concentrations below 10 mg MB&"1 were less effective was the very poor
effluent quality which removed some of the dissolved MB by physical and
chemical reactions (6). Higher concentrations than 15 mg MB&"1 decrease
the light penetration into a darker medium, decreasing the effectiveness of
the photooxidation process.
The effect of the radiation time on the COD and MBAS values of the
effluents is shown in Table 1. The fact that COD values remained practically
unchanged after 6 h of irradiation proved the presence of OM which were
probably refractory to photooxidation. The methylene blue active substances
169
-------
380
300
O* 200
§ 100
0.0
12.0
10.0
CO
7.0 <
5.0
CO
3-0 <
1.0
0.0
Figure 1.
0.0 5.0 10.0 15.0 20.0 25.0
MB CONCENTRATION, ppm
The effect of MB concentration on COD (°) and MBAS (*) values.
TABLE 1. THE EFFECT OF RADIATION TIME ON THE COD AND MBAS VALUES OF THE
EFFLUENTS*
Radiation Time
(h)
0.0
0.5
1.0
2.0
4.0
6.0
8.0
10.0
COD
(mg 02/&1
460
360
290
240
160
130
125
125
MBAS
(mg lAS/i}
11.3
7.8
6.3
4.6
2.1
1.6
1.3
1.1
* Working conditions: 12 mg MB/£; 32±2°C; 1980±60 yEm 2s~1. Blank in dark
after 10 h: COD, 380, MBAS, 9.8.
were much more sensitive to the irradiation time and continued to be degraded
after 6 h, remaining less than 10 percent of their initial value (.11.3 mgJl"1)
after 10 h.
170
-------
Th(
Effect of the Photochemical Treatment of Waters on Microorganisms
Laboratory Experiments with Eschevichia coli.
Samples of tap water and municipal effluents, to which an innoculum of
fecal E. coli had been added, were exposed to solar irradiation in graduated
glass cylinders (100 m£) in the presence of MB or rose bengal (RB), under
continuous aeration (7). Table 2 shows the effect of MB concentration^ on
survival of the coliforms after 28 min of irradiation (sunlight intensity:
2,030 uEm"2s~1; temperature: 32±2°C).
TABLE 2. THE EFFECT OF MB CONCENTRATION ON THE DESTRUCTION OF COLIFORMS*
MB Concentration
5.00
Viable Coliforms (MPN/100 m£)
Sewage Tap Water
0
0
0
1
2
4
.00
.25
.50
.00
.00
.00
5
2
9
1
.6
.9
.5
.1
X
_
X
X
X
-
10
10
10
10
8
4
3
3
7.
4.
4.
2.
2.
5
8
0
1
0
X
X
X
X
X
<20
10
10
10
10
10
8
3
3
3
3
<20
* Initial coliform density: sewage 1.3 x 109, inoculated tap water 9.2 x 108
The bactericidal effect was obtained by destructive photooxidation and
was not a mere dye-sensitizer inhibition of coliform growth (7). Almost the
same results were obtained by another group of researchers (8) .
The effect of sunlight intensity and exposure time on the coliforms'
survival in effluent samples containing 2 rngMBA"1 is shown in Table 3 (the
initial coliform count: 1.3 x 109 MPN/100m£; temperature: 32±3°C).
The data presented in Table 3 show the existence of interraction among
dye concentration, length of exposure, intensity of irradiation, and coliform
destruction. One of the most important conclusions regarding this data is
that the intensity of solar radiation may not be a limiting factor, when
disinfection of waters by sensitized photooxidation is considered. As far
as the destruction of coliforms in sewage effluents is concerned, the
results obtained by this method appear to be much more satisfactory than
those reported for chlorination (9).
The Effect of Photochemical Treatment of Waters on Algal Growth
A study was carried out to determine the effects of various concentra-
tions of MB and RB at different sunlight exposure times on the reduction of
171
-------
TABLE 3. THE EFFECT OF SUNLIGHT INTENSITY AND EXPOSURE TIME ON THE
DESTRUCTION OF COLIFORM IN SEWAGE*
Sunlight Radiation Viable Coliforms
Exposure Time Intensity Amount (MPN/100
(min) (uEnf^""1) (Em~2)
0
4
28
42
40
120
150
0
2,030
2,030
2,030
68
68
68
0
0.49
3.40
5.10
0.16
0.49
0.61
1.3 x 109
1.8 x 108
7.9 x 1Q2
<20
1.7 x 10"
7.9 x 102
<20
* Control sample after 150 min incubation in dark at 35°C had 1.1 x 109
coliforms/100 m£.
the algae population (10). The behavior of three algae from the Lake of
Galilee (Israel) were studied in batch cultures: the dinoflagellate
PeT'id-in'ilffn ainatum fa westii and two chlorophyta algae, Ped-iastmrn duplex
and Cosmari-um sp. The algae were grown in a minimal artificial medium and
an alternating light cycle (10). Table 4 shows the synergistic effect of
solar exposure and the sensitizer on algal growth. These results suggested
that the algae investigated are sensitive to sensitized photooxidation and
may undergo lethal damage; they might be useful for treatment of industrial
or municipal wastewaters containing pollutants which favor algal development.
The effect of the sensitizer's presence in the culture medium on algal growth
is shown in Figures 2, 3, and 4. These figures and Table 4 demonstrate that
the sensitized photooxidation is adequate also for algal destruction, with-
out suffering from the drawbacks of the conventional method (10). Further-
more, as the dye-sensitizers are eventually photooxidized to uncolored
compounds, no detrimental environmental impact is to be expected.
The Effect of the Photochemical Treatment of Effluent in a Pilot Plant
Scale Experiment
The effluent of a municipal sewage oxidation pond, having about the
same main characteristics as were used .in previous studies C6), was pumped
into an open, epoxy-coated steel reactor CFigure 5). A solution of MB
was continuously added into the effluent (2 g MB/m3 effluent) in a mixing
container connected directly to the reactor. When the effluent depth
reached 25 cm (about 2.5 m3), the suction from the oxidation pond was
stopped and the pump switched to recirculate the treated effluent. The
effluent was contaminated with laboratory cultures of bacteriophages
(coliphage X and F2), polio virus type 1-L Sc (vaccine strain). Samples
taken at different times were bacteriologically analyzed. The results
showed that those bacteriophages which were resistent to chlorination (up to
172
-------
TABLE 4. THE MINIMUM CONDITIONS FOR TOTAL ALGAL DESTRUCTION
Algae
Dye
Type
Solar Exposure
(min)
Incubation Time
(days)*
Pediastrum
Cosmarium
Per-id-ini-wn
Peri-din-iim
(in lake water)
MB
MB
RB
RB
MB
MB
RB
RB
MB
MB
RB
RB
MB
MB
RB
RB
0.40
0.15
1.50
0.80
0.75
0.75
1.20
0.80
0.50
0.25
2.00
0.60
0.50
0.30
1.60
0.80
0
40
0
40
0
30
0
60
0
30
0
30
0
60
0
60
7
10
7
10
20
10
10
10
25
14
35
35
14
14
14
14
* Minimum incubation time when algal population count was zero, without
subsequent recovery.
INCUBATION TIME, DAYS
Figure 2. The effect of dye Cppm) on Pertdiniwm.
173
-------
0 7 14 21
INCUBATION TIME, DAYS
Figure 3. The effect of dye Cppm) on Cosmavi-wn.
10 20
INCUBATION TIME , DAYS
Figure 4. The effect of dye (ppm) on Ped-Castmm.
174
-------
-.35m
t[ EFFLUENT
Figure 5. Photochemical reactor
30 mg Cl/£) were killed in a few minutes by this method. Polio virus were
completely killed in a period of 5-8 hours depending on working conditions.
Other bacteria and algae were also affected. Since this work is in progress,
more data will be published elsewhere (11).
Detoxification of Organic Pollutants in Water
The agricultural chemicals may reach water ways following their
agricultural use, accidental spillage, or from the pesticide wastewater
industry. These agrochemicals must be decomposed or removed prior to using
such waters for irrigation purposes. Two non-selective herbicides widely
used for general weed control, bromacil and terbacil, were chosen for
photodecomposition studies. Water solutions of bromacil (12) and terbacil
exposed to sunlight are chemically stable for months and probably years.
Therefore, their behavior to sensitized photooxidation might emphasize the
effectiveness of this method.
Sensitized Photooxidation of Bromacil in Water
Sunlight irradiation of an aerated bromacil (3-sec-butyl-5-bromo-6-
methyluracil) aqueous solution (250 mg/A), in the presence of different
sensitizers and an appropriate PH led to complete and fast photodecomposi-
tion of this herbicide (13). Table 5 shows the relative sensitizing effect
of different sensitizers used in experiments. It is to be noted that
sensitizers like riboflavin (RF) and humic acids may be present in natural
and waste waters. Figures 6 and 7 show the bromacil degradation (percent)
as a function of the sensitizer's (RF or MB) concentration and the PH of
the solutions. The colorless solution of bromacil is stable in the entire
PH range studied. The exposure time of solutions to sunlight was 30
175
-------
TABLE 5. RELATIVE SENSITIZING EFFECT
Sensitizer
Concentration (ppm)
6.8
PH
9.2
Rib o flavin
Methylene Blue
Rose Bengal
Humic Acid-a
Humic Acid-b
10
5
5
20
20
'1.00
0.74
0.32
0.06
0.03
1.00
1.11
0.85
0.20
0.08
80 -
0 5 10 15 20
SENSITIZER CONC.(ppm)
I I
O RF (IO ppm
X MB (5 ppm
• NO SENSITIZERS
30 min exp.
10
Figure 6. Bromacil
photodecomposition.
Figure 7. Bromacil
photodecomposition
176
-------
Sensitized Photooxidation of Terbacil in Water
Sunlight irradiation of an aerated terbacil (3-t-butyl-5-chloro-6-
methyluracil) aqueous solution (700 mg/£) in the presence of different
sensitizers, at pH range from 4.0 to 9.2, led to its complete decomposition
(14). Figures 8 and 9 show the photodecomposition of terbacil in the
presence of MB and RF, respectively, as affected by pH (and temperature
for MB case).
In the case of both bromacil and terbacil, sunlight irradiation of the
sensitized solution of these herbicides causes decomposition and under
optimum conditions no trace of them can be found after a few hours of this
treatment. The intermediary products formed in these processes were
isolated and identified (14, 15). Submitting industrial wastes containing
these herbicides to the same photodecomposition procedure also resulted in
a complete destruction of their phytotoxic properties (16).
The high inorganic salts content of the industrial wastes did not affect
the photochemical process. The treated waters and the solution of photo-
oxidation intermediary products were analyzed for their phytotoxicity-
Bioassays were carried out using these waters and solutions to irrigate
sensitive plants in their different stages of development. The results
were completely satisfactory (17).
Figure 8.
60 120 180
TIME (MIN)
Terbacil MB
photodecomposition.
Figure 9,
120 180
TIME (MIN)
Terbacil RF
photodecomposition.
240
177
-------
CONCLUSIONS
A new approach of oxidation of organic pollutants in municipal and
industrial effluents proposes the use of MB as a photosensitizer, air as
the oxygen source, and sunlight energy as the photooxidation inducer. This
approach is especially attractive in arid and semiarid zones where the
climate is favorable for the promotion of photooxidation. In such zones
there is also an acute need for water and this method seems to be cost
effective and also to respond to the water requirements for crop irrigation.
Of course, much more work has to be done in order to transform this new
approach into a practical method.
ACKNOWLEDGMENTS
The multidisciplinary subjects treated in this study necessitated the
cooperation of scientists with a wide variety of backgrounds. Their
efficient collaboration is gratefully acknowledged: Dr. I. Rosenthal
(photochemistry), Dr. B. Juven (bacteriology), Dr. A. Elgavish (algae
metabolism), Dr. J. Marzouk (virology), Dr. S. Saltzman (soil chemistry),
Dr. E. Dunkelblum (organic chemistry), and Dr. M. Horovitz (plant physiology).
REFERENCES
1. Kautsky, H. Quenching of luminescence by oxygen. Trans. Farad. Soc.,
35:216-219, 1939.
2. Zepp, R. G., G. L. Baughman, N. L. Wolfe, and R. C. Hollis. Singlet
oxygen in natural waters. Nature, Lond., 267:421-423, 1977.
3. Gollnick, K. Type II photo-oxygenation reactions in solution. Adv.
Photochem., 6:1-122, 1968.
4. Kearns, D. R. Physical and chemical properties of singlet molecular
oxygen. Chem. Rev., 71:395-427, 1971.
5. Foote, C. S. Mechanism of photosensitized oxidation. Science, 162:
963-970, 1968.
6. Acher, A. J., and I Rosenthal. Dye-sensitized photo-oxidation — a new
approach to the treatment of organic matter in sewage effluents.
Water Res., 11:557-562, 1977.
7. Acher, A. J., and B. I. Juven. Destruction of the fecal coliform in
sewage water by dye-sensitized photooxidation. Appl. Environ. Micro-
biol., 33C5):1019-1022, 1977.
8. Gerba, C. P., C. Wallis, and J. L. Melnick. Disinfection of waste
water by photodynamic action. J. Water Poll. Control Fed., 49(4):
578-583, 1977.
9. Kott, Y. Hazards associated with the use of chlorinaLed oxidation
pond effluents for irrigation. Water Res., 7:853-862, 1973.
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10. Acher, A. J., and A. Elgavish. The effect of photochemical treatment
of water on algal growth. Water Res., 14(3): in press, 1980.
11. Acher, A. J., J. Marzouk, and J. Manor. Disinfection of effluents by
a photochemical treatment — Pilot plant experiments. Progress report
to Israeli Council for R&D, Jerusalem (Nov. 1979, in Hebrew).
12. Moilanen, K. W., and D. G. Crosby. The photodecomposition of bromacil.
Arch. Environ. Contain, and Toxic., 2:3-8, 1974.
13. Acher, A. J., and S. Saltzman. Dye-sensitized photodecomposition of
bromacil in water. J. Environ. Qual., 9(1): in press, 1980.
14. Acher, A. J., S. Saltzman, N. Brates, and E. Dunkelblum. Photosensi-
tized decomposition of Terbacil in aqueous solutions. J. Agric. Food
Chem., 28(4): in press, 1980.
15. Acher, A. J., and E. Dunkelblum. Identification of bromacil photo-
decomposition products. J. Agric. Food Chem., 27(6):1164-1167, 1979.
16. Acher, A. J. A method for decomposing herbicidal residues in
solutions. Israel Pat. Appl. 58495 (19 Oc., 1979).
17- Acher, A. J., S. Saltzman, and M. Horowitz. Sunlight induced detoxi-
fication of herbicides in water. Progress Report to Volcani
Institute. 1980.
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PBS3-142273
LAND TREATMENT OF COMBINED
MUNICIPAL/INDUSTRIAL WASTEWATERS
C. E. Pound, Vice President
R. W. Crites, Project Manager
Metcalf & Eddy, Inc.
290 North D Street, Suite 505
San Bernardino, California 92401
ABSTRACT
The most direct measure of benefits from land treatment of municipal/
industrial wastewaters is a cost comparison. Two case studies are presented
which illustrate several ways that land treatment can be used to provide
cost effective solutions to municipal/industrial wastewater management.
Selection by one city of a separate but publicly owned land treatment sys-
tem for industrial wastes resulted in reductions in cost from $1.10/1,000
gal to $0.35/1,000 gal for the industrial waste contributions. Selection
by another city of a combined municipal/industrial land treatment resulted
in reducing costs for one example industry from $1.70/1,000 gal to $1.12/
1,000 gal as compared to an activated sludge system. In the first case,
both industrial and municipal systems were eligible for federal grant
funding because the parallel approach was most cost effective. The
municipal wastewater was treated to 40 mg/1 BOD and the industrial waste-
water was applied raw except for screening. In the second case, a single
land treatment system was constructed as the most cost effective because
the industrial waste flow was small compared to the total combined flow.
INTRODUCTION
With the introduction of the financing and revenue program guidelines
promulgated pursuant to Public Law 92-500, industrial waste dischargers
have been faced with the difficult decision to combine their wastes with
the municipal discharger or to treat and dispose of their waste indepen-
dently. Although the decision had to be faced prior to this time, the
inclusion of equal allocation of cost and the industrial payback provision
made the decision more critical. Prior to the passage of PL 92-500, it
was not uncommon to find industrial dischargers paying substantially less
per unit of waste contribution than that of the municipal resident because
of political decisions made to favor industrial growth in the community.
With these arbitrary choices removed from the municipality and industrial
dischargers, the decision has been reduced to mainly one of economics.
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Financial decisions are easily made when a balanced analysis of the
facts can be presented. Until recently this balance was difficult to obtain,
It was not uncommon ten years ago to find the industrial discharger with
little or no real data on flows and biological oxygen demand (BOD) or
suspended solids (SS) contributions to the local treatment plant. This
often led to serious differences of opinion when it came to paying for
treatment costs to the local municipality. Consequently, when the
industrial discharger began to consider the possibility of an independent
waste management operation, he was very often lacking basic design data.
He may have understood the total volume of discharge over the operating
season but had little or no comprehension of the diurnal variations in
either quantity or quality of his waste flows. This deficiency compounded
the difficulty of making decisions regarding the question of independent
waste management.
As the industrial waste discharger searched for a means of managing
and disposing of-his wastewater independently, he sought the least complex,
the most economical, and the most flexible system available. Where the
industrial waste discharger was located in or near a rural environment,
and where waste constituents were non-toxic and biodegradable, the option
of land treatment was given serious consideration.
Industrial waste dischargers as used in the context of this paper,
refer to those that have a relatively large flow rate in proportion to
that of the associated municipality and relatively high concentrations of
BOD and/or SS. Further, the industrial classifications include those that
do not contain substantial quantities of toxic pollutants that would
preclude their use on land treatment systems. In essence, these industries
include the food and beverage industries.
The purpose of this paper is to present and discuss two examples of
decisions made by industry and cities that have resulted in the use of land
application for wastewater treatment. Both examples were taken from the
authors' files and were selected to present different types of decisions.
POTENTIAL BENEFITS OF COMBINED LAND TREATMENT
In a discussion of benefits it is necessary to determine to whom the
benefits will accrue, and as compared to what alternatives. Further, a
discussion of benefits in a general context can be very misleading. Never-
theless, the following thoughts will be presented in view of these limita-
tions .
The greatest incentive to combining the industrial waste discharge
with the municipal waste flow is to permit "out of sight, out of mind"
treatment. That is, that the problem can be passed along to others, at
a price, and all of the management's energy can be directed at their primary
function of producing a salable product. If the price for this service
reaches a level where production costs approach an unprofitable level, this
option ceases to be an incentive. Many industries arrived at this condition
as the new revenue programs took effect across the country. This resulted
in one of several actions:
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1. the industry closed down its operation and moved to a more
profitable location,
2. converted from combined treatment with the municipal facility
to an independent treatment and disposal system such as land
treatment, or
3. took steps to influence the local community to adopt a more
cost effective (relative to the industry) methods of treat-
ment and disposal.
There are both benefits and drawbacks to the independent land treat-
ment alternative. Benefits usually include reduced capital and operating
costs, independent operation and investment of capital in their own land
that has historically accrued in value in time. The drawbacks include the
use of their own working capital, and the management energies involved in
scheduling and managing the waste treatment and disposal facilities.
Conversion of the publicly owned treatment facilities to land treat-
ment also include a set of benefits and drawbacks. Benefits to industry
usually include provision of management and operation of the facilities
by others and provision of capital funding on a no interest loan basis
(even less if industrial cost recovery is abandoned). The drawbacks to
industry may be relatively few unless there are disagreements between
industry and the municipal officials.
If conversion of the publicly owned facility is made by separating
the industrial waste system from the domestic system, the preceding bene-
fits can be gained for industry plus additional benefits to both, such as:
1. Overall costs will be less, especially for industry, because
the industrial waste stream could likely be applied to land
without pretreatment.
2. The design and operation of that portion of the facility can
be closer to optimum if the transient loads associated with
large industrial waste dischargers are removed from the domes-
tic waste flows.
3. Costs associated with disinfection of domestic wastes can be
avoided for the industrial waste stream if separated from
the domestic waste stream.
Each of these conditions may be seen in the following case examples.
EXAMPLE NO. 1
The first case involved a moderately sized community with two major
food processing industries connected to the municipal wastewater system.
During the three month canning season, industries A and B contribute 88%
of the BOD and 79% of the SS in the combined wastewater. This peak loading
required the preapplication treatment facilities to be overdesigned for the
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remaining nine months of the year when the industrial flows and loads are
reduced to less than 20% of the combined flow and load. The average flows
and loads are presented in Table 1.
TABLE 1 FLOWS AND LOADS FOR EXAMPLE 1
Flow,
mgd
BOD load,
1,000 Ib/day
SS load,
1,000 Ib/day
Canning season
(7/15 - 10/15)
Industry
Domestic
Total
7.3
4.7
12.0
39.1
5.5
44.6
28.1
7.6
35.7
Remainder of Year
Industry 1.1
Domestic 4.7
Total 5.8
0.8
5.5
6.3
0.8
7.6
8.4
At the beginning of the facilities planning step, both industries were
discharging to the treatment plant. The initially recommended alternative
was to treat the combined municipal/industrial wastewater in aerated lagoons
and then apply the effluent to crop land for irrigation. To apply the
wastewater effluent to the land it was necessary, under existing require-
ments, to reduce the BOD from over 500 mg/L to less than 40 mg/L. The
total annual cost of this alternative was $0.68/1,000 gallons.
The two industries were alarmed that their costs under this alter-
native would increase substantially over their previous costs to about
$1.10/1,000 gal. They proposed that alternatives involving direct land
treatment of the industrial wastewater be investigated. Two alternatives
were developed that would offer savings both to the municipality and to
the industries. These alternatives are summarized with their estimated
costs in Table 2.
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TABLE 2 WASTEWATER TREATMENT ALTERNATIVES
FOR EXAMPLE 1
Applied
BOD, mg/L
Total
Annual Costs,
$/l,000 gal
Industrial
Costs,
$/l,000 gal
Alternative 1
Separate cannery land
application at
municipal site
Alternative 2
Separate cannery land
application at
individual sites near
industries
Base
Combined treatment and
application
1,500
1,500
40
D.62
0.69
0.68
0.35
0.68
1.10
As indicated in Table 2, the alternatives did not produce significant
reductions in the overall cost of the system for the combined municipality
and industry. There are, however, significant savings for the industries in
both Alternatives 1 and 2.
Industry A had some previous experience with land treatment and it
studied a private land treatment system for comparison with the municipal
alternatives. A private system was approximately the same cost as Alter-
native 1. The advantages of Alternative 1 were that:
1. The municipality would own and operate the system, and would
provide the capital financing.
2. The alternative would be eligible for a full federal grant as
the most cost effective plan for the municipality.
The advantages of the private land application system for Industry A were
seen as follows:
1. Industry would have control of their own destiny and be able
to reduce future treatment costs.
2. The land purchased would be an excellent investment.
3. A local farmer would manage the off-season farming operation
and provide revenues to offset some of the operating costs.
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The appearance of a local farmer who was willing to operate the farm
and manage the wastewater application was the deciding factor. Industry A
decided to drop out of the municipal system and construct its own land treat-
ment system.
Industry B, on the other hand, decided to remain in the municipal sys-
tem. Their wastewater will be maintained separate from municipal wastewater
and will be treated by the irrigation method of land treatment.
The municipality was therefore able to design a secondary treatment
system for a wastewater with a relatively constant BOD. The system of
preapplication treatment is also designed for a significantly smaller
hydraulic capacity.
Each member of this decision trio was able to achieve the desired
least cost treatment alternative using land treatment.
EXAMPLE NO. 2
This example involves a moderately large city in California that has
one milk processing plant which operates continuously throughout the year.
This industrial example will serve to illustrate the advantages of land
treatment as compared to an activated sludge type of biological treatment
followed by disinfection and discharge to a surface receiving water. Table
3 presents the flow and wastewater characteristics for both the example
industry and the city as a whole.
TABLE 3 FLOWS AND LOADS FOR EXAMPLE 2
Industry alone*
Combined MunicipalH-
Plant Capacity+
Flow,
mgd
0.152
17.33
22.50
BOD Load,
Ib/day
2,360
30,820
46,900
SS Load,
Ib/day
1,180
32,410
51,400
* Only one of several industrial contributors.
+ Portions of flow treated at two different plant; 3.5 mgd and
19.0 mgd design capacities, respectively.
Initially, the concept was developed to treat the wastewater by bio-
logical treatment to permit discharge to a local irrigation canal. Use of
a canal is required because there is no continuously flowing river nearby to
receive the effluent. To permit discharge to the canal, the effluent
quality would have to meet the relatively stringent BOD and SS standards of
20 mg/L. Further, as shown in Table 4, disinfection would be required
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to achieve a seven day mean value of 23 MPN/100 ml of total coliforms. In
case there was less than a 1:1 dilution ratio in the canal, disinfection
would be increased to 2.2 MPN/100 ml.
TABLE 4 DISCHARGE REQUIREMENTS FOR THE
DIFFERENT TREATMENT ALTERNATIVES
Constituent
BOD, mg/L
SS, mg/L
Surface
Discharge
20
20
Crop
Irrigation
40
40
Total Coliforms,
MPN/100 ml 23
* Not stipulated, but fencing of farm lands
is required to prevent public access.
Two alternative processes were evaluated for meeting the discharge
standards; overland flow and conventional activated sludge. Estimated
costs are presented for these alternatives in Table 5. Obviously, the
costs estimated for the overland flow process are lower than the costs
for the activated sludge process, but because the time schedule for
compliance was short and the technology for overland flow treatment had
not been applied on a scale of this size before that time (1974) , the
activated sludge alternative was approved for implementation. Although
not shown, the economic analysis included selling the reclaimed water
to an irrigation district, with revenues partially offsetting the higher
costs of biological treatment provided by either activated sludge or
overland flow, making these two alternatives the most cost effective.
However, negotiations with the irrigation district broke down and the
alternative of discharge to the canal system ceased to be economically
viable.
The alternative finally adopted and implemented was biological
treatment to 40 mg/L BOD in an aerated lagoon system followed by irrigation
of farm lands. The costs for this alternative are also presented in Table
5.
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TABLE 5 COMPARISON OF COSTS FOR ALTERNATIVE TREATMENT PROCESSES
Treatment Process
Cost Item
Capital Cost, $1,000*
Operation & Maintenance Costs
.Gross Annual O&M, $1,000
.Annual Revenues, $1,000
.Net Annual O&M, $1,000
Cost to the Industry, $/yr
, $/l,000
Activated
Sludge
20,270
1,500
1,500
94,360
gal 1.70
Overland
Flow
13,960
962
962
58,000
1.04
Irriga-
tion
24,590+
1,375
418
957
62, loot
1.12
* July 1977 Cost. Includes Steps 1, 2, and 3.
+ Includes $3,350,000 for land acquisition. This cost is based on
actual contract prices. Others are estimated.
+ Includes industrial cost recovery provisions.
A review of the annual costs to the industry for each alternative in
Table 5 reveals an interesting circumstance. Biological treatment pro-
cesses designed mainly for organic constituents will result in relatively
high costs for high strength industrial wastes. Land treatment systems
designed primarily around hydraulic parameters can result in the lowest
costs for high strength industrial wastes. On the other hand, high flow
rate, low strength wastes may result in disproportionately high costs
for industry using a land treatment system
CONCLUSIONS
Because industries must make a profit on an ongoing basis, they must
be sensitive to the cost of treating and disposing of their wastewaters.
Sensitivity must involve consideration of total costs as well as relative
costs. Costs must be similar to those of industries in other areas of the
country. In any case, treatment costs should be as low as possible.
Land treatment, either as an independent operation or as a combined
municipal/industrial operation, can help industries achieve the lowest
possible treatment costs. Similarly, land treatment can permit municipal-
ities to meet their treatment and disposal obligations at the least over-
all cost and simultaneously provide an industrial development incentive
for their community.
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THE UTILIZATION OF SEWAGE SLUDGES ON CROPLAND
L. E. Sommers and D. W. Nelson
Agronomy Department
Purdue University
W. Lafayette, IN 47907
ABSTRACT
The application of sewage sludges on cropland is receiving increased
emphasis because of environmental and economic constraints being placed on
alternative disposal methods. Sewage sludges contain macronutrients (N, P,
and K) and trace elements (e.g., Zn, Cu, Mn, B, and Mo) required for plant
growth and thus, sewage sludges can be used as a low analysis fertilizer
material. Numerous studies have indicated that comparable crop yields can be
obtained by fertilizing soils with either sewage sludges or conventional
inorganic fertilizer materials. However, sewage sludges also contain other
constituents, primarily of industrial origin, which may limit their appli-
cation rate on cropland. The sludge components of greatest concern include
pathogens, slowly-degraded organics (e.g., PCB's) and non-essential heavy
metals (Ni, Cd, and Pb). Approaches being developed for land application
of sewage sludges are based on maintaining the productivity of agricultural
cropland and the quality of the environment. Developing a land application
system involves the following considerations: (1) pathogens; (2) nitrate
and heavy metal leaching into groundwaters; (3) effects on human health re-
sulting from Cd accumulation in crops; (4) phytoxicity due to increased soil
levels of Cu, Zn, and Ni and; (5) contamination of crops with persistent
organics such as PCB's. To minimize problems arising from pathogens, sludges
applied to cropland are stabilized by anaerobic digestion or an equivalent
process. Application techniques can be utilized to minimize accumulation of
persistent organics on many crops. Limitations on annual applications of
plant available N and Cd will minimize nitrate leaching and Cd uptake by
crops, respectively. The life of a sludge application site is based upon
the cumulative amounts of heavy metals added. It is particularly important
that soil pH be maintained at 6.5 or above during and after sludge appli-
cation to prevent phytoxicity from Cu, Zn, and Ni and to reduce plant uptake
of Cd. This paper will emphasize the impact of sludge additions on soil and
plant properties and the rationale used for developing a land application
system.
188
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INTRODUCTION
One approach to solve the sewage sludge disposal problem faced by many
municipalities and industries is the application of sludge on agricultural
land. In addition to being an economical alternative, application of sewage
sludges on cropland provides the growing crop with nearly all required macro-
and micronutrients. In most cases, the concentrations of plant nutrients
in sewage sludge are not present in the appropriate ratio and supplemental
fertilization may be needed (e.g., K). However, sewage sludges commonly con-
tain constituents which are potentially hazardous to plants or to animals
or man after assimilation into crops. When considering application of sewage
sludges on agricultural land, the sludge constituents of greatest concern
are pathogens (human or animal), persistent organics (primarily chlorinated
hydrocarbons), and heavy metals (e.g., Pb, Zn, Cu, Ni and Cd) . The objec-
tives of this paper are to evaluate the behavior of sludge components in
soils and crops and to describe the procedures and considerations used in
developing a system for application of sewage sludge on agricultural crop-
land.
BEHAVIOR OF SEWAGE SLUDGE COMPONENTS IN SOILS
Pathogens
The majority of sewage sludges applied to agricultural land are treated
by a process to reduce the potential for dispersal of pathogens. Typical
treatment processes include anaerobic or aerobic digestion, lime (CaO) treat-
ment, extended storage in lagoons and composting. In spite of these stabi-
lization practices, sludges typically contain coliform organisms, bacterial
pathogens (Salmonella, Shigella), protozoa (Entamoeba), helminthic parasites
(Ascaris) and viruses (1). Disease transmission could result from sludge
applications which contaminate crops consumed raw by humans (e.g., vegeta-
bles) , adhering to forages grazed by animals or entering surface or ground
waters through runoff or leaching, respectively. In all cases, the ability
of the organism to survive in soils or on plant surfaces is a prerequisite
for the existence of a health problem.
The survival of selected pathogens that may be present in sewage
sludges is shown in Table 1. The majority of bacteria can persist for time
periods ranging from several days to 10 months in soils or on vegetation.
Ascaris ova are capable of withstanding adverse environmental conditions in
soil resulting in survival for periods up to 7 years. The survival of
viruses in soils amended with sewage sludge has not been adequately evaluated
but viruses have been isolated from soils for 8-13 days after sludge appli-
cation (2, 3). Several factors influence the survival of pathogens in soils
including temperature, moisture, pH, sunlight, toxic substances, competitive
organisms, and nutrient supply (4). Studies on the survival of salmonellae
in soils indicated a survival time of 7 days in dry soils at 39°C (5). Sur-
vival was strongly influenced by interactions between soil moisture, tempera-
ture and inoculum carrier (waste or saline solution). Fecal califorms
added to crops through wastewater irrigation are retained in the upper 8 cm
of the soil and exhibit a 10% survival over 48 hrs. (6). In addition,
189
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10 hours of bright sunlight completely eliminated fecal coliforms retained
on alfalfa forage (7). The application of sludge to cropland has been shown
to have minimal impact on the coliform and virus levels in both surface and
ground waters (8). Except for Ascaris ova, the majority of sludge-borne
pathogens will be at very low levels in soils amended with sludges after a
one year period (1, 9).
Proper management of a sludge application site is essential to mini-
mize any potential pathogene related problems. Sludge application guidelines
are being developed by numerous states in addition to the U.S. EPA (10). The
current recommendations to manage pathogens can be summarized as follows:
1. All sludges applied to soils growing human food-chain crops
should be stabilized by a process which significantly reduces
pathogens (i.e., aerobic or anaerobic digestion, lagooning,
air-drying, heat-drying, composting, CaO treatment),
2. Stabilized sludges should not be applied to root or vegetable
crops which can be consumed raw; root or vegetable crops
can be grown on the site 18 mos. after sludge application,
3. Animals should not be grazed on pastures treated with sludge
for one month after application.
Even though concern has been expressed about the addition of pathogens to
soils in sludges, there has not been any significant widespread disease
problems associated with land application of sludges.
Persistent Organic Compounds
Many sewage sludges contain organic compounds, primarily chlorinated
hydrocarbons, which are relatively resistant to decomposition in soils and
are of concern from a human health standpoint. The chlorinated hydrocarbon
pesticides and the polychlorinated biphenyls are the principal sludge-borne
compounds receiving attention. A recent survey has indicated that the ma-
jority of sewage sludges contain relatively low concentrations (<1 to 10
mg/kg) of these compounds although specific industrial inputs to the sewage
system can result in elevated sludge levels (12). A recent survey of
sludges produced in Indiana indicated that the median PCB concentration was
7 mg/kg (12) while sludges from Michigan typically contain <1 mg PCB's/kg
(13). Since PCB's are no longer being widely used for industrial purposes,
the concentration in sludges should decrease with time.
Both chlorinated hydrocarbon pesticides (14) and PCB's (15) are resis-
tant to rapid degradation in soils. For PCB's, the rate and extent of
degradation increases as the percentage chlorine in the compound decreases
(16). Even though chlorinated organics persist in soils, they are not
generally assimilated by plant roots and translocated to above ground
parts such as the grain or fruit. In soils treated with 100 mg (PCB/kg,
elevated concentrations were found in whole carrots (17). However, 97%
of the PCB was located in carrot peelings suggesting that physical
190
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Table I. Survival of Selected Pathogens in Various Media.
Survival time,
Organism - Media days
Coliforms Soil Surface 38
Vegetables 35
Grass and Clover 6-34
Streptococci Soil 35 - 63
Fecal streptococci Soil 26 - 77
Salmonellae Soil 15 - >280
Vegetables and Fruits 3-49
Grass and Clover 12 - >49
Shigellae On Grass (Raw Sewage) 42
Vegetables 2-10
Tubercle bacilli Soil >180
Vabrio cholerae Vegetables and Fruit <1 - 29
Water and Sewage 5-32
Leptospira Soil 15 - 43
Entamoeba histolytica Soil 6-8
cysts Vegetables <1 - 3
Enteroviruses Soil 8
Vegetables 4-6
Ascaris ova Soil Up to 7 yrs.
Vegetables and Fruits 27 - 35
Hookworm larvae Soil 42
a
Adapted from (1).
191
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absorption to the root occurred rather than plant uptake. In addition, the
carrot foliage did not contain detectable levels of PCB's. Similarly,
essentially no plant uptake (orchardgrass and carrot foliage) has been found
when polybrominated biphenyls are applied to soils (18). Since PCB's are
somewhat volatile, application of sludge to the soil surface could result
in absorption of volatilized PCB's by plant stems and leaves (19). This
mechanism of plant contamination with PCB's can be eliminated by incorpo-
rating sludge into the upper 10 to 15 cm of soil.
The principal problem arising from chlorinated hydrocarbons is direct
ingestion by grazing animals of surface-applied sludge adhering to forages.
Research has indicated that sludge solids may constitute from 22 to 32%
of the forage dry weight immediately following sludge application (19) . The
application of sludge to the stubble after mowing the forage resulted in
less contamination. Dairy cattle are most susceptible to PCB contamination
of forages because PCB's are readily partitioned into the milk fat. The
allowable level of PCB's in animal feedstuffs is 0.2 mg/kg and thus, it is
possible to calculate allowable PCB levels in sludge given a sludge appli-
cation rate, forage yield, percent sludge retention on forages and an
assimilation factor for the animal (21).
Based on the above considerations, the following recommendations are
pertinent to managing PCB's and other persistent organics in land applica-
tion systems:
1. Sludges containing >10 mg PCB/kg should be incorporated into the
surface soil (0-20 cm),
2. Sludges should not be surface applied on forages grazed by dairy
cattle. For other animals, forages can be grazed 30 days after
application.
Heavy Metals
The heavy metals of most concern when applying sewage sludges to agri-
cultural land are Pb, Zn, Cu, Ni and Cd. Several studies have been con-
ducted to determine the range of metals in various municipal sewage sludges
with representative data being presented in Table 2. Although both domestic
wastes and urban run-off contain metals, it is felt that industrial wastes
contribute the majority of metals found in municipal sewage sludges and that
industrial pretreatment can significantly reduce the metal content of
sludges (22). This view is also supported by the low metal content of
sludges from treatment plants serving only residential areas. It has been
suggested that a "typical" domestic sewage sludge would contain 2,500
mg Zn/kg, 1,000 mg Pb/kg, 1,000 mg Cu/kg, 200 mg Ni/kg and 25 mg Cd/kg,
(23). However, since sludge-borne metals added to soils accumulate in the
plant root zone (upper 20 cm), heavy metal loading is a consideration even
when low metal sludges are applied to agricultural land.
The rationale for considering Pb, Zn, Cu, Ni and Cd involves protect-
ing the human food-chain from metal contamination and preventing the
deterioration of soil productivity. Lead additions to soils are limited
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TABLE 2. CONCENTRATION OF SELECTED CONSTITUENTS IN SEWAGE SLUDGES.'
Component
N
P
K
Pb
Zn
Cu
Ni
Cd
Sommers
Range
<0.1 - 17.6
<0.1 - 14.3
<0.1 - 2.6
13 - 19,700
101 - 27,800
84 - 10,400
2 - 3,520
3 - 3,410
(38)
Median
3.3
2.3
0.3
500
1,740
850
82
16
7
1.0 -
—
—
mS/ K-g
10 -
30 -
178 -
17 -
3 -
Echelberger
Range
24.7
-
-
28,200
34,300
7,700
9,450
1,020
(12)b
Median
7.1
451
1,770
685
141
16
Range
52 - 4,900
228 - 6,430
240 - 3,490
10 - 1,260
1 - 970
Chaney (39)
Median
__
500
1,430
790
42
13
All data on an oven-dry solids basis.
PCB's: range, <0.04 - 241; median, 7.2.
-------
Table 3. Effect of sewage sludge application on the concentration of Cd in
selected crops.
Crop
Total
Cd
applied
Cd in vegetative tissue at a
rel. sludge appl. rate of
0
0.25
0.50
1.0
Cd in edible part at a relative
sludge application rate of a.
0
0.25
0.50
1.0
Ref .
. mg/kg
Corn
Soybeans
Lettuce
Radishes
Tomato
Peas
Beans
Turnips
Oats
101
64
4.3
2.4
77.6
64
3.3
3.9
5.5
3.3
3.9
5.5
3.3
3.9
5.5
3.3
3.9
5.5
3.9
5.5
64
0.2
0.42
0.08
0.35
0.22
1.59
_. . .
0.92
0.92
0.66
0.66
0.02
0.46
0.46
0.59
0.59
0.77
1.4
1.07
0.17
0.50
0.89
2.24
___—
0.13
1.14
3.2
1.55
0.23
0.96
2.73
1.78
.
___
0.16
1.64
10.9
2.04
0.27
1.08
5.78
1.80
___—
0.88
3.10
___—
0.75
2.10
0.20
0.55
1.70
0.59
2.60
1.96
0.09
<0.05
0.09
0.11
0.31
0.41
0.61
0.46
0.46
0.13
0.29
0.29
0.08
0.12
0.12
<0.03
0.04
0.04
0.42
0.42
0.16
0.18
<0.05
0.09
0.11
0.31
0.51
1.28
0.14
0.20
0.04
' "™
0.49
0.40
<0.05
0.09
0.15
0.57
0.75
1.72
0.18
0.33
0.04
— — — _
0.76
0.81
<0.05
0.10
0.15
0.92
0.78
2.67
0.55
1.70
0.31
0.33
0.92
0.33
0.20
0.39
0.04
0.07
0.23
0.42
1.30
0.84
28
0
31
52
45,
b
53
54
54
53
54
54
53
54
54
53
54
54
54
54
b
The amount of Cd applied for each treatment is equal to the relative rate times
the total Cd applied.
L. E. Sonmers and D. W. Nelson, unpublished data.
194
-------
because of the potential for direct ingestion of Pb contaminated soil or
dust by animals or infants. It is well established that sludge applications
do not result in appreciable increases in the Pb content of crops (23, 24).
Even though Cu and Zn are essential micronutrients for all crops, excessive
additions of Cu and Zn, along with Ni, can be toxic to plants resulting in
undesirable depressions in crop yields. Fortunately, additions of sludge-
borne Cu, Zn, and Ni to soils will not pose a health risk to animals or
humans because the plant concentrations of these metals which cause phyto-
toxicity are lower than those causing health problems (24).
Cadmium has received the greatest attention as a potential human
health problem resulting from application of sewage sludges on cropland.
The concern over Cd arises from current estimates of dietary Cd intake by
the U.S. population (26). After ingestion, Cd accumulates primarily in the
kidney and, after extended exposure to elevated dietary Cd, a chronic kid-
ney malfunction (proteinuria) may result (27). Thus, if sludge applications
increase the .Cd content in the human diet, there is the potential for a
health problem after 20 to 50 years. In addition, excessive Cd levels can
be obtained in plant tissues before phytoxicity occurs. It should be noted
that only 1 to 2% of the agricultural cropland is required for application
of all municipal sewage sludge produced in the U.S. (24).
Soil and plant factors influencing metal uptake by crops.
Since Cd is the metal of most concern, representative Cd data will be
emphasized to illustrate the behavior of metals in soil-plant systems.
Plant species differ markedly in their response to application of Cd con-
tained in sewage sludges. The concentrations of Cd in several vegetable and
crop species are shown in Table 3. In general, leafy vegetables tend to
accumulate greater concentrations of Cd than fruit, tuber or grain crops.
Also, the vegetative parts of most plants contain higher concentrations of
Cd than the reproductive or storage organs. Even though the leaf can con-
tain elevated Cd levels, only minimal increases in grain Cd are observed
for corn (22, 24, 28-30), suggesting that corn is an ideal crop for soils
treated with sludge. Other grain crops, such as soybeans, oats and wheat,
also exclude Cd from entering the grain but to a lesser extent than corn
-(241. __ In_addition to species...differences in uptake of Cd from soils, culr-
tivars of..corn (31), .soybeans (321, and.:lettuce (33) vary in Cd accumulation,
indicating a potentital for plant breeding programs to develop cultivars
which are ideally suited for growth on soils amended with sludge.
In general, the concentrations of Zn in crops tend to parallel those
of Cd while Cu and Ni are altered to a smaller extent by sludge applications
(24). As with Cd, Zn concentrations are greatest in the vegetative parts
of plants rather than the fruit or grain.
Soil properties exert a strong influence on the uptake of metals by
crops. The solubility of heavy metals in soils is likely controlled by
sorption onto clay minerals or hydrous oxides of Fe, Al and Mn, chelation
or complexation with organic matter and precipitation with phosphate,
sulfide or carbonate anions (24). Either directly or indirectly, soil
pH has a marked effect on the above metal retention mechanisms. Soil
195
-------
Table 4. Effect of soil pH on Cd concentration in representative crops.
Control soil3
Crop
Soil
L
pH
H
Tissue Cd
L
H
Sludge-amended soil
Soil
L
pH
H
— ^-mg/kg
Lettuce (Bibb)
Lettuce (Romaine)
Lettuce (Boston)
Cabbage
Carrot
Swiss chard
Corn grain
Swiss chard
Corn grain
Lettuce
Swiss chard
Soybean grain
Oat grain
Orchardgrass
Swiss chard
Oat grain
Swiss chard8
Oat grain
a L - low pH; H -
4.*
4.6
4.6
4.6
4.6
6.1
6.1
6.1
6.1
4.9
4.9
4.9
4.9
4.9
5.7
5.7
5.3
5.3
high pH
pH adjoisted by liming; 11.
° pH decreased (L)
" .« .r.. . u..* *>AA
by adding
6.3
6.3
6.3
6.3
6.3
„_
__
6.3
6.3
6.3
6.3
6.3
6.7
6.7
6.4
6.4
2 kg
S';
= /T,,
1.18
0.88
0.95
0.19
0.96
1.31
0.04
1.31
0.04
1.6
_ —
0.20
0.22
0.34
0.6
0.05
0.89
0.11
0.78
0.78
0.90
0.16
0.71
«_
_»
0.6
0.8
0.08
0.04
0.17
0.5
0.04
0.49
0.07
Cd/ha added in sludge
80 metric
6.0
6.0
6.0
6.0
6.0
5.3
5.3
4.5
4.5
4.9
4.9
4.9
4.9
4.9
5.2
5.2
5.6
5.6
[33].
6.7
6.7
6.7
6.7
6.7
6.7
6.7
6.6
6.6
6.3
6.3
6.3
6.3
6.3
6.2
6.2
6.6
6.6
Tissue Cd
L
H
mg/kg
8.40
2.25
3.10
0.35
2.29
13.50
0.29
10.60
0.52
20.4
37.1
1.07
2.12
1.67
1.9
0.23
70.4
3.38
4.18
1.78
1.85
0.19
1.25
2.91
0.12
2.10
0.29
4.6
2.9
0.38
0.38
0.66
0.6
0.07
17.7
0.54
tons/ha sludge applied [33J.
.1 ^^j
pH adjusted by liming; old sludge disposal site - total Cd in soil was 0.25 and 2.8
for control and sludge-treated soils, respectively [55].
pH adjusted by liming; old sludge disposal site - DTPA extractable Cd was 0.13 and
0.55/jg/g for control and sludge-treated soils, respectively [22].
as In f but DTPA extractable Cd was 0.94 and 6.3^/g for control and sludge-
treated soils, respectively.
196
-------
cation exchange capacity (CEC) is a function of soil clay and organic
matter content and pH and has been used as an index of those soil proper-
ties minimizing metal solubility and thus plant uptake (34, 35). However,
recent studies indicate that soil CEC per se is not likely to influence
Cd concentrations in crops (36, 37).
Soil pH appears to be the critical parameter for minimizing uptake
of sludgeborn metals by crops. The data presented in Table 4 illustrate the
effect of soil pH on Cd uptake from sludge-amended soils by a variety of
crops. In most cases, substantial reductions in plant Cd concentrations
result from liming acid soils. Zinc concentrations in plants have been
found to decrease from liming to a greater extent than Cd in some crops. It
is also apparent that crops differ in Cd uptake following lime additions
to increase soil pH. Metal uptake will be minimized by sludge applications
to calcareous soil where the pH is continuously buffered by the presence
of CaC03. In addition, the cation exchange sites in soil organic matter
are weakly acidic, functional groups which serve to buffer soil pH. Thus,
CEC may be important in non-calcareous soils by minimizing pH changes during
the oxidation of reduced N and S contained in sludges.
Limits for sludge metal additions to soils.
The U.S. EPA in addition to some state regulatory agencies have devel-
oped regulations concerning the maximum amounts of Pb, Zn, Cu, Ni and Cd
allowable on agricultural land used for growing food-chain crops. Food-
chain crops are typically defined as those crops than can enter the human
diet either with (wheat, corn) or without (leafy vegetables) processing.
Researchers in the USDA and Agricultural Experiment Stations proposed limits
for Pb, Zn, Cu, Ni, and Cd which should allow the growth of all crops after
termination of sludge applications, provided the soil pH is maintained at
6.5 or above (34). The metal loadings suggested are shown in Table 5. The
use of soil CEC was based on the fact that metal solubility and thus, plant
availability tends to decrease with increasing CEC in most soils of the
north central United States. The CEC concept may be valid for Cu, Zn and
Ni but it does not appear to be related to the plant availability of Cd
(36, 37). Scaling metal additions to soil CEC does not imply that sludge-
borne metals are present in soils as exchangeable cations because it has
been well-established that nearly all metals in sludge-amended soils are
nonexchangeable with a neutral salt (40, 41).
The U.S. EPA has developed regulations only for Cd additions to crop-
land (10). These limitations can be summarized as follows:
1. The pH of the soil/sludge mixture must be >_ 6.5 at the time of
sludge application.
2. Annual Cd additions are limited to 0.5 kg/ha/yr if leafy
vegetables, root crops, vegetables or tobacco are grown.
197
-------
Table 5. Maximum amounts of Pb, Zn
CU, Ni, and Cd that can be applied
to agricultural cropland
(34, 35).
Soil cation exchange
capacity, meq/100 g
Metal <5 5-15 >15
Pb
Zn
Cu
N1b
Cd°
500
250
125
125
5
kg/ha
1,000
500
250
250
10
2,000
1,000
500
500
20
o
Soil must be maintained at pH 6.5 or
.above.
Contained in U.S. EPA Criteria (10).
3. For other food-chain crops, the annual Cd additions follow a
phased reduction from 2 kg/ha/yr (present to 6/30/84), to
1.25 kg/ha/yr (7/1/84 to 12/31/86), to 0.5 kg/ha/yr
(after 1/1/87).
4. The cumulative Cd applied must be < 5 kg/ha if the background
soil pH is £ 6.5.
5. The cumulative Cd applied is as shown in Table 5 for soils
with a background pH> 6.5 and for soils with a background
pH < 6.5 provided the pH is 6.5 at the time food-chain
crops are grown.
For soils used for growth of animal feed only, neither annual nor cumulative
Cd application limits were established but soil pH must be 6.5 and a detail-
ed facility plan is needed to prove that the crop will not directly enter
the human diet. Only guidelines have been established for Pb, Zn, Cu and
Ni by the U.S. EPA (35).
Nitrogen
The factor limiting the annual application rate of many sludges is the
available N content. A potential problem in land application of sludges is
the leaching of N0_ below the plant root zone and ultimately into ground
water. This can occur when available N additions to soils exceed the N
requirement of the crop grown whether the N added is from sludge, animal
manures, or fertilizers. Thus, a well-designed system will use annual
sludge application rates which are consistent with the N needs of the
crop grown.
198
-------
Table 6. Effect of annual sewage sludge applications on yields of corn and
soybeans.
Crop
Year
Max . annual
sludge
applied
Grain yield at a
application
ob
0.25
relative
rate of
0.5
sludge
1.0
Soybeans
(ref. 45)
Corn
(ref. 28)
1969
1970
1971
1972
1973
1974
1968
1969
1970
1971
1972
1973
1974
1975
43
59
109
31
14
59
51
48
53
128
26
62
49
_—_
2.28
2.01
1.80
2.04
1.68
1.44
4.16
8.96
5.53
6.06
8.94
4.00
3.47
8.15
3.02 3.24
2.77
1.93
2.55
1.90
1.71
6.03
9.34
7.48
6.50
8.62
6.05
3.21
9.36
3.02
2.10
2.74
2.00
2.00
7.16
9.42
7.62
6.92
8.99
6.72
3.85
9.44
3.36
2.85
2.13
2.93
2.11
2.12
7.02
9.44
8.63
7.88
8.82
7.63
5.11
9.43
Sludge application rates can be calculated by multiplying 0, 0.25, 0.5, or
1.0 and the maximum rate shown.
Control plots were fertilized with K for soybeans and with N, P and K for
corn.
199
-------
Table 7. Effect of sludge type on corn grain yields (47).
Soil type
Grain yieldc
Year
No N
NH.NO- Ca-sludge Al-sludge Fe-sludge
Conestoga
loam
Caledon loamy
sand
Oneida clay
loam
1973
1974
1975
1973
1974
1975
1973
1-974
1975
4.17
4.89
7.13
3.88
3.87
3.63
3.71
1.58
5.56
5.97
6.57
7.67
3.43
4.21
3.75
3.55
1.44
4.70
ic tons /ha
5.9'4
6.47
7.00
3.47
3,87
4.46
5.12
3.35
6.04
5.39
7.11
8.03
3.05
3.78
3.00
3.55
1.61
5.78
5,81
7.03
7,61
3.03
4.52
3.53
4.56
2.32
5.86
Nitrogen application rates were 100 kg N/ha from NH.NO- and 200 kg N/ha from
Ca-, Al- or Fe-sludge. Anaerobically digested sludges from three treatment
plants where either Ca(OH) , Al (SO,)-
during waste water treatment.
or Fe Cl_ was added for P removal
200
-------
Several fractions of N in sewage sludge, are available for plant up-
take. In anaerobically digested sludges, NH4 constitutes from 25 tc>JQt of
the total N while NO, is present in only trace amounts (42) . Both NH4 and
NO" are readily available for plant uptake. The organic N applied to soils
insewage sludge will undergo partial decomposition resulting in release of
plant available inorganic N. The amount of organic N mineralization is
usually estimated from laboratory or field decomposition studies which
suggest that from 15% (43) to 20% (34) of the organic N is released the
first year after application. In subsequent years, the percentage of orga-
nic N mineralized decreases.
Part of the N applied to soils in sewage sludge will be lost through
volatilization on denitrification. Following surface application of
sludges, up to 60% of the NH7-N can be lost through NH3 volatilization (44).
Thus, the rate of sludge applied each year to provide adequate N for plant
growth is greater for surface than incorporated applications (34, 35).
Nitrate losse.s can also occur after sludge application through denitrifi-
cation (microbial reduction of NO- to N-0 and N under anaerobic conditions)
This N loss is not corrected for directly but it has been considered in the
development of conventional N fertilizer recommendations for various crops.
Nitrogen fertilizer recommendations have been developed in all regions of
the U.S. for the major crops grown and these values are used in determining
the appropriate sewage sludge application rate for cropland.
Several field experiments have been conducted to compare yields of
crops grown on soils fertilized with sewage sludge and conventional inor-
ganic fertilizer materials. Representative data for crop yields are shown
in Tables 6 to 8. In essence, crop yields are increased with increasing
rates of sludge application. The data in Table 6 are also noteworthy in
that the recommended metal limits shown in Table 5 were exceeded for Cd
and Zn without a reduction in yield (soil pH > 6.5). Elemental analysis
of the leaf and grain of corn (28) and soybeans (45) indicated that both
Zn and Cd were elevated by sludge application.
Corn grain yields have been determined on soils treated annually with
NH4N03 and three different anaerobically digested sludges (47). Sludges
applied at a rate of 200 kg N/ha gave similar corn grain yeilds as 100 kg
N/ha added as NH4N03 (Table 7). On the loamy sand soil, no yield response
was obtained for either NH^O or sludge. The yeild response of corn was
similar for all three types of sludges. Soil analysis indicated that
NO. -N concentrations in the 0-15 cm depth averaged 92 and 59 mg/kg for
soils treated with 400 kg N/ha as NH NO and sludge, respectively. This
study concluded that the optimum rate of sludge application was 200 kg N/ha
for corn resulting in minimal leaching of NO into ground water. In a
related study, it was shown that yields of both rye forage and corn grain
increased with increasing sludge application rates (Table 8). Corn grain
yields were significantly increased for three years following a single
application of sludge. This result is consistent with mineralization of
organic N for several years after sludge is applied to soils. The studies
cited along with others indicate that optimum yields of agronomic crops
can be obtained with an appropriate rate of sludge application.
201
-------
DESIGN CRITERIA FOR LAND APPLICATION SYSTEMS
As discussed in the previous sections, the major considerations in use
of sewage sludge on agricultural land are: (1) pathogens; (2) persistent
organics; (3) heavy metals - Pb, Zn, Cu, Ni and Cd and; (4) available N.
In addition, sludge applications should not result in contamination of sur-
face waters as a result of runoff. This potential problem can be alleviated
by incorporating the sludge into the soil, surface-applying sludge on only
relatively level soils (i.e., <6% slope), and minimizing sludge application
on frozen soils. Additional information on other site selection considera-
tions has been discussed in recent reviews (34, 48, 49).
Table 8. YIELD OF RYE FORAGE AND CORN GRAIN
FOLLOWING A SINGLE APPLICATION OF
SEWAGE SLUDGE TO A PLANO SILT LOAM
SOIL (46)
Sludge
applied
ff l 2
.
0 3.75 3.14
3.75 3.91 3.84
7.5 4.00 4.82
15 4.06 5.68
30 4.02 6.38
60 3.77 7.13
Yeara
3
,,
2.00
2.13
2.93
3.55
5.34
5.91
Corn grain yields except for rye
year 1.
4
1.35
1.07
1.35
3.14
3.14
4.78
forage in
To design a system for land application of sewage sludge, information is
required on the (1) composition of sewage sludge; (2) soil properties (pH and
CEC) and fertility status and; (3) type and yield level of crop to be grown.
Based on this data, sludge application rates and supplemental fertilizer
needs are determined for each year and the total amount of sludge that can be
applied over a period of years is based on cumulative additions of Pb, Zn,
Cu, Ni or Cd. This basic approach has been recently discussed (50) and can
be summarized as follows:
1. Obtain fertilizer (N, P and K) recommendation for crop grown.
2. If first sludge application proceed to step 3
a. Correct fertilizer recommendation for amounts of residual
N, P and K from previous sludge applications.
3. Select minimum sludge application rate from:
a. N limitation - sludge-borne plant available N (NH, + NO,, +
20% of organic N) applied should equal corrected N fertilizer
recommendation.
b. Cd limitation - as specified in the U.S. EPA Criteria (10).
202
-------
4. At the rate selected in step 3, calculate the amounts of P and
K needed to optimize crop yield.
5. Sum the Pb, Zn, Cu, Ni and Cd added each year.
6. If a metal limit has been exceeded (Table 5) terminate sludge
applications; otherwise, proceed to step 1.
This approach assumes that soil pH is maintained at 6.5 or above whenever
sludge is applied. Since the annual application rates are consistent with
current fertilizer practices, monitoring in excess of routine soil testing
for available P and K and pH is not required. It must be realized that the
above steps only apply to sludges that have been stabilized by an appro-
priate process and that persistent organics (i.e., PCB's) are not present
at concentrations <10 mg/kg.
In summary, sewage sludge can be readily used in the production of
agronomic crops to obtain yields comparable to those from using conventional
fertilizer materials. However, additional management is required to assure
that allowable amounts of Cd and organics are applied to soils, that soil
pH is maintained at 6.5 or above, that sludge applications cease before
phytotoxic concentrations of metal accumulate in soils and that the appro-
priate crops are grown.
ACKNOWLEDGMENT
Research supported, in part, by Western Regional Project W-124 entitled
"Optimum Utilization of Sewage Sludge on Agricultural Land", and published
with the approval of the Director of the Agricultural Experiment Station,
Purdue University, as Journal Paper No. 8105.
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13. R. Sprague, Michigan Department of Natural Resources, Personal Communi-
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14. Helling, C. S., P. C. Kearney, and M. Alexander. 1971. Behavior of
pesticides in soils. Advan. Agronomy 23:147-240.
15. Iwata, Y., W. E. Westlake, and F. A. Gunther. 1973. Varying persis-
tence of polychlorinated biphenyls in six California soils under
laboratory conditions. Bulletin Environ. Contamin. Toxicol. 9:204-211.
16. Clark, R. R., E. S. K. Chian, and R. A. Griffin. 1979. Degradation of
polycholorinated biphenyls by mixed microbial cultures. Applied Environ.
Microbiol. 37:680-685.
17. Iwata, Y., F. A. Gunther, and W. E. Westlake. 1974. Uptake of a PCS
(Aroclor 1254) from soil by carrots under field conditions. Bulletins
Environ. Contamin. Toxicol. 11:523-528.
204
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18 Jacobs, L. W., S. F. Chou, and J. M. Tiedje. 1976. Fate of PBB's in
soils: Persistence and plant uptake. J. Agric. and Food Chem.
24:1198-1201.
19. Haque, R. , D. W. Schmedding, and V. H. Freed. 1974. Aqueous solubility,
adsorption, and vapor behavior of polychlorinated biphenyl Aroclor 1254.
Environ. Sci. Technol. 8:139-142.
20. Chaney, R. L., and C. A. Lloyd. 1979. Adherence of spray-applied
liquid digested sewage sludge to tall fescue. J. Environ. Qual.
8:407-411.
21. Fries, G. F. 1980. An assessment of potential residues in animal pro-
ducts from application of sewage sludge containing polychlorinated
biphenyls to agricultural land. Presented at Symposium on Evaluation
of Health Risks Associated with Animal Feeding and/or Land Application
of Municipal- Sludge, Tampa, FL.
22. Chaney, R. L., and S. B. Hornick. 1978. Accumulation and effects of
cadimum on crops. Proc. First International Cadimum Conference.
pp. 125-140.
23. Chaney, R. L., and P. M. Giordano. 1977. Microelements as related to
plant deficiencies and toxicities. In L. F. Elliott and F. G.
Stevenson (eds.), Soils for Management of Organic Wastes and Wastewaters,
Soil Science Society of America, Madison, WI. pp. 235-279.
24. Application of sewage sludge to cropland: Appraisial of potential
hazards of the heavy metals to plants and animals. Rpt. No. 64,
Council for Agricultural Science and Technology, Ames, LA. (Also
reprinted as MCD-33 (EPA-430/9-76-013) by the U.S. Environmental Pro-
tection Agency).
25. Chaney, R. L. 1973. Crop and food chain effects of trace elements in
sludges and effluents. Proc. of Conference on Recycling Municipal
Sludges and Effluents on Land, National Association of State Universi-
ties and Land Grant Colleges, Washington, D. C. pp. 129-141.
26. Braude, G. L. , C. F. Gelinek, and B. Corneliussen. 1975. FDA's over-
view of the potential health hazard associated with the land application
of municipal wastewater sludge. In Proc. 1975 National Conference
Municipal Sludge Management and Disposal. Information Transfer, Inc.,
Rockville, M.D., pp. 214-217.
27. Doyle, J. J. 1977. Effects of low levels of dietary cadimum in
animals—a review. J. Environ. Qual. 6:111-116.
28. Hinesly, T. D., R. L. Jones, E. L. Ziegler, and J. J. Tyler. 1977.
Effects of annual and accumulative applications of sewage sludge on the
assimilation of zinc and cadimum by corn (Zea mays L.). Environ. Sci.
Technol. 11:182-188.
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29. Hinesly, T. D., E. L. Ziegler, and G. L. Barrett. 1979. Residual
effects of irrigating corn with digested sewage sludge. J. Environ.
Qual. 8:35-38.
30. Webber, L. R., and E. G. Beauchamp. 1979. Cadimum concentration and
distribution in corn (Zea mays L.) grown on a calcareous soil for three
years after three annual sludge applications. J. Environ. Sci. and
Health B-14:459-474.
31. Hinesly, T. D., D. E. Alexander, E. L. Ziegler, and G. L. Barrett.
1978. Zinc and cadimum accumulation by corn inbreds grown on sludge
amended soil. Agron. J. 70:425-428.
32. Boggess, S. F., S. Willavize, and D. E. Koeppe. 1978. Differential
response of soybean varieties to soil cadimum. Agron. J. 70:756-760.
33. Giordano-, P..M. , D. A. Mays, and A. D. Behel, Jr. 1979. Soil tempera-
ture effects on uptake of cadimum and zinc by vegetables grown on
sludge-amended soil. J. Environ. Qual. 8:233-236.
34. Application of Sludges and Wastewaters on Agricultural Land: A Planning
and Educational Guide. 1976. B. D. Knezek and R. H. Miller (eds.),
North Central Regional Research Publication 235, Ohio Agricultural
Research and Development Center, Wooster, OH. (Also reprinted by the
U. S. Environmental Protection Agency as MCD-35).
35. Municipal Sludge Management: Environmental Factors. 1977. MCD-28
(EPA430/9-77-007) U.S. Environmental Protection Agency, Washington,
D. C.
36. Latterell, J. J., R. H. Dowdy, and G. E. Ham. 1976. Sludge-borne
metal uptake by soybeans as a function of soil cation exchange capacity.
Commun. Soil Sci. and Plant Analysis 7:465-476.
37. Haghiri, F. 1974. Plant uptake of cadimum as influenced by cation
exchange capacity, organic matter, zinc and soil temperature. J.
Environ. Qual. 3:180-183.
38. Sommers, L. E. 1977. Chemical composition of sewage sludges and
analysis of their potential use as fertilizers. J. Environ. Qual.
6:225-232.
39. Chaney, R. L., S. B. Hornick, and P. W. Simon. 1977. Heavy metal
relationships during land utilization of sewage sludge in the north-
east. In R. C. Loehr (ed.), Land as a Waste Management Alternative.
Ann Arbor Science, Ann Arbor, MI. pp. 283-314.
40. Silviera, D. J., and L. E. Sommers. 1977. Extractability of copper,
zinc, cadimum, and lead in soils incubated with sewage sludge. J.
Environ. Qual. 6:47-52.
206
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41 Latterell J. J. , R. H. Dowdy, and W. E. Larson. 1978. Correlation
of extractable metals and metal uptake of snapbeans grown on soil
amended with sewage sludge. J. Environ. Qual. 7:435-440.
42. Sommers, L. E. , D. W. Nelson, and K. J. Yost. 1976. Variable nature
of chemical composition of sewage sludges. J. Environ. Qual. 5:303-306.
43. Keeney, D. R. , K. W. Lee, and L. M. Walsh.' 1975. Guidelines for the
Application of Wastewater Sludge to Agricultural Land in Wisconsin.
Technical Bulletin No. 88, Dept. of Natural Resources, Madison, WI.
44. Beauchamp, E. G. , G. E. Kidd, and C. Thurtell. 1978. Ammonia volati-
lization from sewage sludge applied to the field. J. Environ. Qual.
7:141-146.
45. Hinesly, T. D., R. L. Jones, J. J. Tyler, and E. L. Ziegler. 1976.
Soybean -yeild responses and assimilation of Zn and Cd from sewage sludge-
amended soil. J. Water Pollution Control Fed. 48:2137-2152.
46. Kelling, K. A., A. E. Peterson, L. M. Walsh, J. A. Ryan, and D. R.
Keeney. 1977. A field study of the agricultural use of sewage sludge:
I. Effect on crop yield and uptake of N and P. J. Environ. Qual.
6:339-344.
47. Soon, Y. K., T. E. Bates, E. G. Beauchamp, and J. R. Moyer. 1978.
Land application of chemically treated sewage sludge: I. Effects on
crop yield and nitrogen availability. J. Environ. Qual. 7:264-269.
48. Witty, J. E., and K. W. Flach. 1977. Site selection as related to
utilization and disposal of organic wastes. In L. F. Elliott and F.J.
Stevenson (eds.). Soils for Management of Organic Wastes and Waste-
waters, Soil Science Society of America, Madison, WI. pp. 327-345.
49. Principals and design criteria for sewage sludge application on land.
1978. In Sludge Treatment and Disposal, Part II, Sludge Disposal.
Environmental Research Information Center, U. S. Environmental
Protection Agency (EPA-625/4-78-012). pp. 57-112.
50. Sommers, L. E., and D. W. Nelson. 1978. A model for application of
sewage sludge on cropland. _In Proc. First Annual Conference of
Applied Research and Practice on Municipal and Industrial Wastes,
Madison, WI. pp. 307-326.
51. Kelling, K. A., D. R. Keeney, L. M. Walsh, and J. A. Ryan. 1977- A
field study of the agricultural use of sewage sludge: III. Effect on
uptake and extractability of sludge-borne metals. J. Environ. Qual.
6:353-358.
52. Ham, G. E., and R. H. Dowdy. 1978. Soybean growth and composition as
influenced by soil amendments of sewage sludge and heavy metals: Field
studies. Agron. J. 70:326-330.
207
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53. Dowdy, R. H., and W. E. Larson. 1975. The availability of sludge-
borne metals to various vegetable crops. J. Environ. Qual. 4:278-282.
54. Giordano, P. M., and D. A. Mays. 1977. Yield and heavy-metal content
of several vegetable species grown on soil-amended with sewage sludge.
In H. Drucker and R. E. Wildung (eds.), Biological Implications of
Metals in the Environment. National Technical Information Services,
Springfield, VA (Conf-750929). pp. 417-425.
55. Chaney, R. L., P. T. Hundemann, W. T. Palmer, R. J. Small, M. C. White,
and A. M. Decker. 1978. Plant accumulation of heavy metals and
phytotoxicity resulting from utilization of sewage sludge and sludge
composts on cropland. In Proc. Conf. on Composting of Municipal
Residues and Sludges, Information Transfer, Inc. Rockville, MD.
pp. 86-97.
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PB83-1U2299
UTILIZATION OF ACTIVATED SLUDGE FROM COMBINED MUNICIPAL/INDUSTRIAL
WASTEWATER TREATMENT FOR ANIMAL AND POULTRY FEED
MATMOR Central Feed Mill
Mobil Post Evtach, Israel
TEXT
I work at the largest feed mill in Israel which produces 22-24,000 m.
tons per month of finished feed for farm livestock. As nutritionists, we
have to look for unconventional materials for feed. Almost all of our raw
materials for livestock feed comes from the U.S.A., the prices of which are
frequently increasing.
We are now taking into account new materials such as dried poultry ma-
nure for ruminants and activated sludge from sewage for monogastric animals.
The approach of the nutritionist to sludge is from a nutritional point
of view only. Upon approaching such a product, the following should be
checked.
1) If the material is free from harmful elements, bacteria, pesti-
cides, herbicides, etc.
2) That the material has a nutritional value, and will be economical,
at least regarding protein and energy.
The first material I would like to talk about is DIGOSOL (which is regis-
tered in Israel), which is the end product of a methane fermentation system.
It is used mainly as a feed component for cattle and pigs, and can also be
safely used for daily cattle but with little advantage.
TABLE! CHEMICAL ANALYSIS
Crude Protein (N x 6.25) 13% + 2
Crude Fat 4% + 1
Cellulose 9% + 1
Nitrogen-free Extract 18% + 1
Total Organic Matter 44% + 3
Ash 52% + 3
Moisture 10% + 1
209
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TABLE 2 COMPOSITION OF ASH:
Calcium
Phosphorus
Iron
Magnesium
Cobalt
Copper
Manganese
Zinc
11 - 14%
1.8 - 2.2%
1.0 - 1.2%
0.8 - 1.2%
200 ppm
300 ppm
350 ppm
2500 ppm
TABLE 3 COMPOSITION:
Digosol
Crude Protein kg 135
Crude Fat kg 45
Crude Fiber kg 90
Calcium kg 120
Phosphorus kg 20
T.D.N. (Total 475
Digestible Nutrient)
Cottonmeal Soyameal
415 440
15 1,0 ,
125 70-
1.5 . ' ' \2'. 5
i
9.8" - 6.0
, 725 760
A trial was conducted to establish the influence of Digosol on the rate
of growth and feed conversion of calves. The experimental group was fed the
same diet from which was removed the following:
10 kg corn
2 kg D.C.P-
5 Rg soyameal
8 kg limestone
and was replaced by 25 kg. Digosol.
Twelve calves (Frezian, an Israeli breed) took part in the trial. Each
animal was weighed at the beginning and end of the trial and at regular
monthly intervals. The animals were fed ad lib. In addition to the above-
mentioned feed,each calf received 2 kg. of hay daily.
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No. of calves
Average starting weight
Average weight at completion
Average general addition of weight
No. of days of trial
Average daily weight increase (gm)
Digosol
6
274.2 kg
478.0 kg
203.8 kg
183 days
1114 + 30 gm
Control
5
271.0 kg
473.0 kg
202.8 kg
191 days
1062 + 29 gi
The Digosol group-of calves increased their weight during 183 days by
only 1 kg. Therefore, we can assume that feed containing 25 kg. Digosol is
in no way harmful and no change was found in the calves.
The second product I would like to talk about is activated sludge.
According to the experts, from 1 cu. m. of sewage we can produce ^ kg. of
sludge.
The first study is a trial of baby chicks who were fed dried sludge.
The results of this trial showed us that chicks can be fed such sludge with-
out suffering harmful consequences. There was no mortality and no lack of
appetite. The sludge was sterilized at the nuclear center at Nahal Soreq.
TABLE A CHEMICAL ANALYSIS:
Crude Protein 30.7%
N.P.N. 5.2%
(Non-protein nitrogen)
Crude Fat 2.2%
Ash 29.7%
Absorbed Protein 57.2%
Metabolic Energy 2315
211
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TABLE B AMINO ACIDS
A.S.
Cottonmeal
Soyameal
Argimine
Lysine
Methionine
Cystine
Histidine
Leucine
Isoleucine
Phenybalamine
Tytosine
Valine
6.15
4.17
2.12
0.37
1.56
8.31
4.69
5.41
4.17
6.97
11.0
4.13
1.25
1.54
2.65
5.82
3.21
5.36
2.46
4.56
7.48
6.30
1.44
1.49
2.37
7.48
5.28
4.95
3.08
4.98
Trial of chicks
The trial was carried out with baby chicks one week old, and for the
first week they received standard feed.
TABLE C
If O" \f O" If &
Jxg iS-g IN.&
Activated sludge
Soya
Ground nut hulls
Sorghum
Corn
Oil
Alfalfa
Fish meal
D.C.P.
Limestone
Salt
Methionine
Vitamin
Crude protein
Protein tested
Metabolic energy
0
320
0
420
150
40
20
20
14
9
2.5
1.4
3.5
21.2
23.4
2680
50
270
20
420
150
40
20
20
0
0
0
1.5
3.5
21.2
22.3
2840
100
230
15
420
150
40
20
20
0
0
0
1.
3.
21.
19.
2830
6
5
2
1
212
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TABLE D RESULTS:
Activated sludge 0 kg 50 kg 100 kg
2-3 weeks
Weight increase - gm. 227 215 213
Feed consumption 370 363 379
Feed efficiency 1.63 1.69 1.78
3-4 weeks
Weight increase - gm. 296 286 281
Feed consumption 537 515 527
Feed efficiency 1.81 1.95 1.85
1-4 weeks
Weight increase - gm. 665 640 636
Feed consumption 1113 1085 1127
Feed efficiency 1.67 1.70 1.77
The increase in weight was almost equal in the trials. Whatever the
chemical analysis a low amount of protein was found which is the reason for
the slight difference in weight.
I would like to point out that in previous studies a big liver was found.
In the group that was fed 100 kg. sludge, the big liver is a sign that the
sludge contains some toxic elements.
Both these materials contain a large amount of Ash, which does not have
to be considered as a negative aspect where added nutrients can be utilized.
The biggest problem we have here is the lack of uniformity, which stems
from the difference between the basic materials.
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PB83--U2307
WATER POLLUTION: INDUSTRY AND GOVERNMENT
WORKING TOGETHER - A CASE STUDY OF MUNCIE,
INDIANA'S INDUSTRIAL PRETREATMENT PROGRAM.
J. M. Craddock
Director
Division of Water Quality
Muncie, Indiana 47304
This is a technical conference dealing xjith the many and varied problems
involving industrial waste entering municipal plants. There have been and
will be many papers presented on the technical side of industrial problems,
therefore I would like to also address some closely related areas.
I believe when one looks at a case study of this type one must also
look at and address areas other than just parts per million (ppm) or percent
reduction. In order to have a reduction of industrial waste such as heavy
metals there were certain attitudes, philosophies and modes of operation that
were used or instituted to achieve this goal.
The question needs to be asked, what can a community do to have direc-
tion over its own future in the area of water pollution control, and the pro-
per operation of its wastewater treatment plant with regard to industrial
waste, the setting of industrial waste limits and protecting its receiving
stream.
With the passing of Public Law 92500 in 1972, plus other new laws and
regulations being instituted on the state and federal level, the ability
for local Government and industry to keep up with the new and changing re-
quirements in the field of industrial control is becoming almost impossible.
In March 1972, the city of Muncie, Indiana created the Division of Water
Quality,a testing and enforcement agency within the Muncie Sanitary District.
Muncie, Indiana, is a typical midwestern community having a population
of approximately 100,000. Located north of Indianapolis, Muncie has a sig-
nificant industrial sector employing over 30 percent of the local work force.
The White River flows through the city, ultimately receiving the storm run-
off, as well as the effluent from the wastewater treatment plant.
With the addition of the DWQ, the MSD program became a "total" approach
because now the MSD had the additional flexibility to monitor water quality,
establish standards, control industrial dischargers and enforce pretreatment
214
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regulations. Protection of the Muncie water resources could now be performed
by a local agency responsible to the citizens of Muncie. This approach is
similar to fire or police protection at the local level. Protection of the
water resources in Muncie should be the responsibility of Muncie residents.
Only when the local agency fails to provide this service should state or
Federal agencies step in.
The initial responsibilities of the DWQ were as follows:
(a) Perform all laboratory testing for the wastewater treatment
plant;
(b) Monitor the industrial dischargers using the MSB sewerage
system and wastewater treatment plant;
(c) Enforce the applicable MSD ordinances relating to sewer use
and.pretreatment and develop new ordinances if necessary;
(d) Prepare spill control and countermeasure capabilities to
minimize water pollution and/or fish kills in the event of a
spill;
(e) Assume responsibility for testing local swimming areas for
bacterial safety;
(f) Perform any scientific research in the aspects of water
pollution necessary for the MSD to fully meet its responsibilities
to the Muncie area citizens; and
(g) Monitor all streams and locate illegal discharges.
In 1972, the need for a formal industrial pretreatment program in Muncie
was based on the recognition of five factors. These were:
(a) A significant industrial sector existed in Muncie discharging
an unknown quantity of wastewater of an unknown quality into
the MSD system.
(b) Existing heavy metals data for plant influent and sludge
suggested relatively high metals concentrations;
(c) Industrial wastes are not always compatible with domestic
sanitary wastewater treatment plants;
(d) A method was needed to assure that all non-domestic users of the
MSD system were assessed fees in a fair and equitable manner; and
(e) The receiving stream for MSD effluent was particularly sensitive
due to low flow conditions and no dilution during the summer.
In recognition of these factors, we initiated a program to develop a
new, more detailed sewer use ordinance and develop a data base upon which to
215
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support the ordinance and the regulation of non-domestic dischargers to the
MSB system.
The overall objectives of the industrial pretreatment program were as
follows:
(a) Minimize potential upset conditions at the treatment plant due to
industrial discharges;
(b) Minimize incompatible pollutants from passing through the treatment
plant to the White River;
(c) Minimize treatment plant sludge disposal problems caused by
excessive concentrations of toxic materials;
(d) Establish and maintain a data base sufficient to calculate sewer
use.surcharge fees;
(e) Prevent water quality violations resulting from illegal direct
dischargers into surface waters within the MSB jurisdictional
boundaries.
A good data base was essential to the pretreatment program including
process descriptions, plant layout, personnel, water usage, and a complete
effluent quality profile. The more accurate this information, the more
fairly the pretreatment program can be implemented. An accurate data base
which is continually updated is critical to the long term viability of the
program. This is due to the fact that decisions regarding surcharge fees
and enforcement of discharge standards must be based on accurate information.
If not, the credibility of the program suffers. This leads to lack of
community cooperation and program failure.
There are various approaches to develop an acceptable data base. With
respect to effluent quantity and quality, the DWQ chose to sample and analyze
the samples in our own laboratory. This approach was selected because we
believed it would provide the most reliable and consistent results. Obvious-
ly, this approach is more costly and time consuming for the DWQ than, for
example, requiring each user to furnish such data.
Shortly after the DWQ was established, we began the first step in the
process of developing an industrial user data base. Files were developed
for each known or suspected industrial discharger to the MSD system. Infor-
mation was obtained from existing files of the wastewater treatment plant,
industrial directories of the Chamber of Commerce, and water department
billing records. Every possible discharger was included.
The next step was to visit each industry, beginning with the known
users of the MSD system. The purpose of the on-site inspection program
was two-fold. First, to visit each potential discharger to determine
if the physical plant, storage practices and operations might result in
accidental spills of toxic or otherwise unwanted materials to the sewer
system. Often, manufacturing facilities, even though they may not normally
216
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produce a wastewater discharge, utilize materials which could enter the
sewerage system. Secondly, known dischargers were visited to go through the
manufacturing process with appropriate plant personnel to identify water uses
and probable contaminants in the discharge. This information was used to
decide the nature of the monitoring and subsequent analysis program.
Upon completion of the plant visits, all information collected was
reviewed to determine the appropriate order in which the plants would be
sampled. The plants discharging industrial wastes were scheduled for
sampling ahead of those discharging domestic wastes. They were ranked to
determine the priority of the field sampling program. Ranking was based
upon the following criteria:
(a) Type of waste constituents - toxics receiving higher priority;
(b) Flow volume;
(c) Access to sampling points; and
(d) Whether existing data were available.
After several years of testing the Division established the following
limits for metals:
LIMITATIONS ON WASTEWATER STRENGTH
Pollutant Daily Average (mg/1)
Total Cadmium 0.2
Total Copper 2.0
Total Lead 2.0
Total Nickel 2.0
Total Chromium 2.0
Total Zinc 4.0
Total Cyanide 2.0
The establishment of these limitations at Muncie was based upon
several years of monitoring not only the industrial contributors, but also
the plant's influent, effluent, sludge, and water quality above and
below the treatment plant. Developing specific limitations first requires
a knowledge of the industrial processes, the metals loading to the plant
from industry, the actual removal capabilities of the wastewater treatment
plant, sludge disposal requirements and stream water quality.
The DWQ may require the user to construct monitoring facilities to allow
DWQ personnel access for sampling flow measurement. Agency personnel may
217
-------
also inspect the facilities of any user at any reasonable time. Facilities
include all manufacturing areas. Plans and specifications for pretreatment
facilities proposed by users must be submitted to the DWQ before construction
begins. The DWQ must be notified 48 hours prior to startup of new or modi-
fied pretreatment facilities. Spill containment facilities, when appropri-
ate, must be provided by each user. Specific plans for such facilities must
be submitted and approved by the DWQ. When a spill to the sewerage system
does occur, the user must notify the DWQ immediately.
Effective implementation of the industrial waste control program
requires the continuous collection of data defining the characteristics
of the industrial users of the MSD system.
Data obtained from the industrial monitoring program are used for the
following purposes:
(a) To determine compliance with the pretreatment standards
contained in the Industrial Waste Control ordinance;
(b) To determine the appropriate user surcharge fees;
(c) To support appropriate enforcement action when necessary;
(d) To complete reports and forms for the DWQ and state/Federal
agencies; and
(e) To provide a data base to justify modifications to the existing
ordinance when appropriate.
The DWQ presently monitors approximately thirty industrial dischargers
on a routine, unscheduled basis. Eight of these are monitored for deter-
mining surcharges. Other types of monitoring are performed as necessary.
These include scheduled and demand monitoring. Scheduled monitoring means
that the DWQ staff notifies the discharger on the day the sampling is to
take place. Often, samples are split with the discharger for comparison
purposes. Scheduled monitoring usually occurs when a violation has been
identified during the unscheduled monitoring effort. Results may be used
for enforcement. In most instances, composite samples are taken.
Demand monitoring is usually synonymous with some type of emergency at
the treatment plant caused by a suspected or known illegal discharge or spill.
The treatment plant operators may want to determine the characteristics of
the discharge and attempt to identify its source or industry may be aware a
spill has occurred and the DWQ wants to determine remedial measures to pre-
vent plant upset.
The DWQ maintains a complete analytical laboratory which serves the
needs of the DWQ's industrial monitoring program. The laboratory is an
essential aspect of the DWQ's "total program" since it provides the
mechanism for quick and reliable analysis of samples. An added benefit of
having a competent chemistry laboratory is the credibility it establishes
with the industrial sector. This is very important when it comes to solving
218
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problems related to discharges exceeding ordinance limitations. These solu-
tions often cost the user time and money. Willingness to work with the DWQ
tox^ard a solution depends to a large degree on the credibility the DWQ has
with the industry.
All samples received from the Surveillance Section field crew are logged
in by the Chemistry Section chief chemist. The log serves as a record of
when the sample was received, where and when it was taken, and what analyses
must be performed. The sample is then processed immediately or stored for
future analysis. The Chemistry Section follows analytical procedures out-
lined in three references. These are:
(a) "Manual of Methods for Chemical Analysis of Water and Wastes,"
published by the EPA Technology Transfer
(b) "Standard Methods for the Examination of Water and Wastewater,"
14th Edition published by the American Public Health Association
(c) "Annual Book of Standards, Part 31, Atmospheric Analysis, 1975,"
published by the American Society for Testing and Materials (ASTM).
The laboratory maintains an internal quality control program to insure
reliability of the data. The program involves routine tasks applied to all
analytical tests as well as checks on all instrumentation and laboratory ser-
vices. The laboratory participates in the EPA Region V Laboratory Quality
Control Program where pre-analyzed samples are used to test accuracy of tech-
niques. Quality control reference documents used by the laboratory include
"Handbook for Analytical Quality Control in Water and Wastewater Labora-
tories" published by the EPA Technology Transfer Program, and the EPA docu-
ment entitled "Methods for Chemical Analysis of Water and Wastes," also
published by the Technology Transfer Program.
We believe that the success of our industrial pretreatment program de-
pends upon many factors. The manner in which we enforce the regulations may
have the greatest influence of any factor on the continuing success and via-
bility of the program. It demonstrates the sincerity and honesty of all
parties involved. For this reason, decisions regarding appropriate enforce-
ment actions are made very carefully. The following factors are always con-
sidered when making a decision as to appropriate enforcement actions:
(a) Type of violation
(b) Frequency of violation
(c) Effects of the violation on the MSD system and receiving waters
(d) Past record of complying with ordinance and willingness to correct
problems.
(e) History of discharge quality
219
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A great deal of human judgment is included in decisions to implement
enforcement actions. They must be fair, reasonable and supported by factual
information. To date, the DWQ has not been forced to go to court to enforce
the ordinance.
The MSB was established to perform a variety of purposes. One of these
purposes was "to prevent the undue pollution of rivers, streams and water
courses and other water" within its boundaries. 'For the MSD to accomplish
this goal, the water quality of the surface water resources in our boundaries
have to be monitored to allow identification of pollution not presently con-
trolled as well as monitor trends or changes with time. Water quality data
are .necessary to determine the impact of efforts to eliminate pollution. The
DWQ has the task of monitoring the water quality within the MSD boundaries.
This is. the second major element of the DWQ's program and the MSD's "total"
program.
The MSD boundaries encompass nine bodies of water. The White River is
the major river flowing through the District. It receives all runoff and
direct discharges from the MSD treatment plant and other sources. Eight tri-
butaries feed the White River. The Division has established 70 base stations
on the White River and its tributaries.
The results of the baseline station sampling and analysis effort are
used by the DWQ for the following purposes:
(a) To determine the suitability of the White River and tributaries
for recreational use and the propagation of aquatic life;
(b) To monitor the effects of waste discharges including urban
runoff on water quality;
(c) To track adherence to or violation of water quality standards;
(d) To determine patterns of pollution downstream from sources of
pollution;
(e) To provide a source of field samples for Division research;
(f) To establish a baseline record of water quality for use in
various studies, e.g., the 201 Facilities Plan; and
(g) To allow the DWQ to assess progress in improving water quality.
The DWQ is responsible for the cleanup of oil or chemical spills with
the MSD jurisdictional area or in the White River watershed upstream of
Muncie. The staff is on call 24 hours a day to respond. Spill containment
and cleanup equipment is maintained, including booms, straw dams, pumps, and
a trailerable boat.
The Division conducts in-house research projects in areas of direct con-
cern to the MSD. Three research programs initiated by the Division are the
Crop Uptake Program, the Fish Study and the Benthic Macroinvertebrates Study.
220
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The DWQ began heavy metals analysis of the sludge generated by the MSB
treatment plant in 1972. After one year of analysis, and in recognition that
all sludge'was being applied to farm land, the Division believed that the
crop uptake study was necessary. The research program subsequently developed
was intended to answer the basic question of whether sludge application to
farm land would contaminate the soil and crops grown on that soil. The re-
sults would then be used to direct future sludge disposal programs.
A cooperative agreement was initiated with Purdue University's Agronomy
School in October 1973. The agreement specified that the MSD would deliver
digested sludge to Purdue's Herbert Davis Agricultural Center near Parker,
Indiana, where the research would be conducted. Purdue agreed to perform
soils analysis for fertilizer value and determine crop yields. The DWQ
would perfprm the heavy metals analyses on soils and crop yields.
In the area of water pollution control, much emphasis in the past has
been detection of water-pollution through chemical analysis. One of the pro-
blems of monitoring water quality through chemical tests is the limited
number of chemicals or compounds which can be economically tested for. Also,
while there are standard chemical tests which indicate levels of pollution
in a general sense, there is the very real possiblity of missing the regular
or sporadic presence of a biologically toxic substance. By monitoring the
biological communities found within an aquatic system, this type of problem
can be detected and a solution sought. The thousands of creatures living in
the aquatic system come in direct contact with those chemicals which may have
been present at any one time within the water. Biological monitoring of
water pollution is theoretically comparable to continuous twenty-four hour,
365 day per year sampling program of chemical parameters.
Populations of two groups of aquatic organisms, fish and benthic macro-
invertebrates, are being monitored by the Division of Water Quality. Fish,
an important recreational and food resource, are familiar organisms to most
people. Benthic macroinvertebrates (animals which can be seen with the naked
eye and have no backbone) are often overlooked by the public but are receiv-
ing attention from environmental scientists for their value as indicators of
water quality. In the monitoring program, populations of fish and benthic
macroinvertebrates are sampled periodically and the species and numbers
collected are recorded. Anomalous changes in the population structures of
these organisms are indicative of changes in water chemistry and provide the
Division with a fairly reliable tool for assessing changes in water quality.
The benthic samples are being obtained and analyzed at thirty stations
covering 100 miles of the West Fork of the White River and its tributaries.
The objective of the program is to establish a macroinvertebrate baseline.
Baseline is defined as periodic estimations of base station benthic community
structure along with a continuing faunal survey. It is hoped that this work
will lead to the recognition of a correlation between the presence or absence
of particular species and water quality. The Division is striving to develop
taxonomic keys for adult and larval macroinvertebrates so that the species
can be properly identified. They are also developing a new method to sample
these organisms.
221
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The fish study involves the examination of metal concentrations in fish
tissues taken at five stations on the White River and its tributaries within
the Muncie city limits. The DWQ hopes to be able to determine ambient levels
of selected heavy metals in the tissue. Such data may lead to guidelines for
the regulation of trace elements in fish tissues.
The DWQ has two special studies under way. These studies were imple-
mented to obtain additional information on the Sources of metals entering
White River watershed as well as the Muncie wastewater plant.
The Urban Sewer Study involves sampling sewers within the MSB which
carry only domestic sewerage. The purpose of the study is to determine the
amount of heavy metals generated by normal households in Muncie. Results
can then be used as an aid in the regulation of industrial discharges.
Sources of metals in domestic wastewater include plumbing, natural
levels in drinking water, and metals*found in common household cleaning com-
pounds and detergents. In addition, certain metals may enter a sewer system
by infiltration of ground water and storm water.
Five locations are sampled each month. Grab samples are taken from man-
holes at each location. The samples are returned to the DWQ laboratory for
analysis. Eight metals are run on each sample. They are chromium, lead,
cadmium, nickel, copper, zinc, iron and manganese.
The DWQ calculated the following percentages of metal loadings to the
wastewater treatment plant was from non-industrial sources:
Metal Percent
Cr 2.3
Cu 33
Fe 49
Mn 25
Ni 11.5
Zn 15
Pb 8.6
The second special study being conducted by the DWQ involves monitoring
the quality of storm runoff from various major parking areas in Muncie. The
objective of this effort is to assess the impact of urban runoff on the
water quality in the White River. Runoff from rainfall or snow melt is mon-
itored at five major parking areas. Each lot was selected based on its
accessibility and having a single isolated discharge point which does not
carry sewage or industrial wastes. Samples are generally taken after an ex-
tended period of no runoff and when possible, are collected during the
222
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initial runoff period. This assures the worse case conditions will be
monitored.
Governmental agencies that have the task of enforcing laws pertaining to
pollution control also have the obligation to make sure that the industries
affected by those laws are informed when they are proposed, when they become
law, how they work, and to be available to answer any and all questions. If
we are to effectively clean our environment, then we must work together as a
team in a coordinated effort instead of just passing laws and then asking
why they are not being enforced.
The Division of Water Quality and the industrial community of Muncie,
Indiana, have set up an organization that puts both entities on the same side
of the fence, working together instead of against each other. This organi-
zation in called "The Muncie Industrial and Commercial Clean Water and Waste
Management Council." The purposes and membership are as follows:
•
A. Purpose
1. Relate industrial problems to the Division of Water Quality.
2. For industry to understand the Division's goals, responsibilities,
and attitudes.
3. To work together for clean water.
4. To work together for grants in the area of pollution control.
5. To keep informed on the latest laws - local, state, and federal -
that affect the Division of Water Quality and industry in Muncie.
6. To exchange technical information on:
a. Testing procedures.
b. Industrial techniques to abate pollution problems.
7. To work together on future problems and controls in the area of
polution.
8. To help Muncie with respect to industrial development, i.e., type
of community and industrial involvement in community ecological
affairs.
9. To educate the public with respect to industries' role in pollution
abatement.
10. To make sure that the environment will be available for future
generations to use and enjoy as we did when we were children.
223
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B. Members
1. Industrial and commercial establishments with water problems or
possible water problems.
2. Division of Water Quality.
3. Indiana State Board of Health (Industrial Waste Section),
4. Muncie, Delaware Chamber of Commerce.
With this organization the community of Muncie will have input into the
writing of new laws. When a new law is proposed on the federal, state, or
local level, there is a period of time when anyone can voice or write their
views or comments or suggested changes on the proposed law. If the people
affected by the laws, either local or state enforcement agencies or the in-
dustrial commanity are not aware of the law, then there cannot be any input
into its creation or revision to be a good and reasonable working law. This
is an important part in our democratic way of life and needs to be practiced
in the environment field as it is in the other areas of our life.
Communication is our most important factor in accomplishing any goal.
If communication is lacking or almost non-existent in this area, then we will
not effectively reach our goal of cleaning the environment.
To achieve these various goals on the local level several basic items
are a necessity. One is a well equipped laboratory. The second is a well
trained staff. The third is a good ordinance. The fourth is to allow this
section of local government to exist and operate without political pressure.
Without these four basic items, local control and clean up will not happen
as it should. These are the general philosophies, and attitudes we have
developed and instituted in our local program.
We have reduced the metals entering the treatment plant by various
methods including but not limited to actual pretreatment. We have required
industries to discontinue using Cr as an anticorossive agent in cooling
towers. We have also required retaining walls around plating tanks so that
drag out waste cannot reach floor drains. Actual pretreatment is not the
only way to reduce metals entering a municipal plant.
Since 1972 the metal concentration in Muncie's sludge has been reduced
by the following: Cr, 70%; Cu, 59%; Ni, 58%, Pb, 91%; and Zn by 55%. See
Table 1.
In conclusion it is our choice now whether we will communicate with each
other in this problem area, or whether we will misinterpret or misunderstand
what is needed, what can be accomplished, what can be afforded, and what we
have to do together to have a clean environment for future generations to
enjoy and use as we did when we were children.
225
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2200
2000
1800
1600
1400
1200
i
Q-
1000
800
600
400
200
1972 1979
225
-------
1800-
1972 1979
226
-------
480
440 h
40
1972 1979
227
-------
8500-
7500-
6500-
5500-
4500-
3500-
O-
O-
1000-
800-
600-
400-
200-
1973 1979
228
-------
5800
5600-
5400 -
2000-
5,698
Zn
1972 1979
229
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PB83-142315
THE CITY OF CHATTANOOGA
INDUSTRIAL-MUNICIPAL PRETREATMENT PROGRAM
E. G. Wright, Superintendent
G. E. Kurz, Staff Engineer
D. A. Summers, Industrial Monitoring Supervisor
Chattanooga Interceptor Sewer System
Moccasin Bend Treatment Plant
Moccasin Bend Road
Chattanooga, Tennessee 37405
ABSTRACT
Faced with stringent 201 grant requirements to accomplish industrial
waste control for protection of its 50 million dollar wastewater plant expan-
sion, the City of Chattanooga has developed an innovative and comprehensive
industrial pretreatment program to satisfy the conditions in its grant agree-
ment. The goal of the strict compliance schedule in the grant agreement was
to achieve control of industrial wastes by 1983 so that the plant expansion
scheduled for completion then will be able to meet its NPDES permit condi-
tions. The pretreatment program that evolved from the grant conditions is
unique since it was developed simultaneously with the promulgation of EPA's
General Pretreatment Regulations, and has been tailored to meet the require-
ments of EPA's National Pretreatment Strategy. The program developed by
Chattanooga is additionally incorporating the National Categorical Standards
now being issued by EPA and is one of the few cities to have sufficient data
on "Consistent Removal" of toxic pollutants to apply to EPA for Local Removal
Credits. The mass balance technique used by the City for developing local
standards (as required by EPA regulation) has been adopted by the State of
Tennessee and was recommended to the 41 cities in the State required to de-
velop local programs. The results of the industrial waste survey, compre-
hensive sampling program, in-plant studies, and program costs will be of val-
ue to other municipalities required to develop local programs under 40 CFR
403, and to municipalities considering extending the benefits of local credits
to their industries. The significance of cooperation with, and by regulated
industries is highlighted.
INTRODUCTION
EPA proposed in February 1977 a comprehensive, unified National Strategy
for regulating industrial discharges. The overall impact of this regulation
(and its extensions, the National Categorical Standards) may be more
230
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significant in terms of public and private dollars than any other program to
come from the Clean Water Act. While large POTW's have generally been aware
for some years that unregulated industrial discharges cannot be tolerated,
many small and medium sized municipalities (including Chattanooga) have not
been aggressive in this area. One of the most valuable byproducts of this
current round of regulatory activity has been to galvanize these municipali-
ties into taking action to examine their systems, and to evaluate and opti-
mize operation of their POTW's. This paper will discuss the effects of the
pretreatment regulations on the City of Chattanooga. Hopefully, the lessons-
learned reported in this case history can be intelligently applied to support
those parts of the National Strategy that reflect insight and wisdom and
modify those parts that tend to degrade the positive effects of the program.
CASE HISTORY
Plant Expansion
Presently, the city operates a 42 MGD (design) air activated sludge
plant at Moccasin Bend, and a smaller 3.5 MGD activated sludge plant at
Brainerd which will be phased out through the 201 plan. The system serves a
community where half the flow, 65% of the BOD, and 75% of the COD load is
from industry. The larger plant was expanded to its present size and capac-
ity in 1971 and was provided with a Zimpro wet-air oxidation facility to
treat the secondary waste activated sludge. This unit operated unsatisfactor-
ily for about two years before the problems of odor and high organic recycle
became unbearable. At the time of its shutdown, part of the operational
problems of the Zimpro system were attributed to the high industrial waste
load to the main plant. At present, all of the waste activated sludge is
discharged directly to the Tennessee River under interim NPDES standards.
Hydraulic and organic overloads, wide fluctuations of influent character-
istics, and the lack of an acceptable disposal method for the secondary
sludge were problems evaluated through the 201 process. Pilot plant studies
led the consultants as well as the process vendors to the conclusion that
pre-treatment and source control would be necessary before any process could
be made to operate dependably. When these reports were issued to the regu-.
latory agencies,they agreed that a strong and aggressive sewer use ordinance
was needed. Therefore, the city was required to develop and implement a new
and comprehensive ordinance as a special condition to the Step II Grant.
The first ordinance to satisfy the Step II Grant was passed in January
1977. The list of pollutants which would be controlled by the ordinance was
developed utilizing the proposed 208 basin plan standards and the State of
Tennessee Discharge Permit. This ordinance regulated 32 different pollutants
The levels were based on the BPT (Best Practicable Treatment) levels which
were being imposed on direct dischargers by the State of Tennessee under its
own permit system at that time and shown in Table 1.
That ordinance was adopted by the City Commission over the objections of
the industrial community. At that time, there was a definite communications
problem which led to misunderstandings with respect to the goals of the
ordinance. However, the City Commission promised the Chattanooga
231
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Manufacturer's Association (the principle organization of affected indus-
tries) that the City would give every consideration possible to their re-
quests to review the standards, and to determine whether or not a variance
procedure for granting exceptions to the standards would be possible.
TABLE 1. 1977 INDUSTRIAL EFFLUENT LIMITATIONS
Parameter
Biochemical
Oxygen Demand
Chemical
Oxygen Demand
Suspended Solids
Antimony
Arsenic
Barium
Boron
Cadmium
Chromium-Total
Cobalt
Copper
Cyanide
Fluoride
Iron
Lead
Magnesium
Manganese
Mercury
Nickel
Phenols
Phosphorus
Selenium
Silver
Strontium
Tin
Titanium
Zinc
Total Kjeldahl Nitrogen
Oil and Grease (Hexane or
Petroleum Soluble)
Total Dissolved Solids
M.B.A.S. (Non-
Biodegradable)
Organic Toxicants
Average
Concentration
(Mg/1)
*
A
*
5.0
1.0
35.0
55.0
1.0
0.5
10.0
1.0
1.0
45.0
45.0
1.0
10.0
1.0
0.1
3.0
10.0
10.0
0.1
1.0
30.0
10.0
3.0
2.0
60.0
100.0
5,000.0
5.0
N.D.A.
Maximum
Concentration
(Mg/1)
-
-
-
8.0
1.5
50.0
80.0
1.5
1.0
15.0
1.5
1.5
70.0
70.0
1.5
15.0
1.5
0.2
4.5
15.0
15.0
0.2
1.5
50.0
15.0
5.0
3.5
90.0
150.0
7,500.0
8.0
N.D.A.
*Depends on plant design.
232
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Shortly after the adoption of the 1977 ordinance, the City technical
staff developed a new plan for setting ordinance limits based on protecting
plant processes and the environment. The main problem with the 1977 stan-
dards was that they were not the result of a logical thinking process de-
signed to satisfy the requirements specified in Section 307 of the Clean
Water Act; i.e., 1) to protect the treatment plant processes, 2) to prevent
pass-through of inadequately treated pollutants, and 3) to protect the sludge
from contamination by pollutants to a degree that the least costly environ-
mentally safe disposal means could not be used. Rather, the limits that were
used were only based on an estimate of industrial treatment capabilities. In
that regard, the 1977 standards closely resembled the present EPA approach
for the development of National Categorical Standards, and therefore the
local standards suffered many of the same defects and shortcomings as the
EPA National Standards.
Program Development
As part of the 201 process, a strict timetable of compliance milestones
was attached to the Step II Grant Agreement by the State of Tennessee. This
timetable has since been modified by the State Director to conform to the
requirements in the General Pretreatment Regulations and is now included in
all municipal NPDES Permits issued by the State. Table 2 shows all the steps
in a typical NPDES permit. The Chattanooga program has minimally satisfied
all the requirements except for the last two steps which require a public
presentation and formal application for approval.
As NPDES permits are reissued by the State Director, all municipalities
in Tennessee must accomplish Activities 1, 3, and 4, (industrial survey,
develop protection criteria, and adopt an acceptable sewer use ordinance).
Additionally, the State estimates that 41 cities will have to perform all 13
activities for a complete program.
The survey of various lists of industries in Chattanooga resulted in a
list of 340 industries thought to be capable of discharging a nondomestic
waste to the sewer system. These industries were contacted by letter and re-
quired to complete a permit application which included a wastewater charact-
erization for the 32 pollutants in the ordinance. The application also in-
cluded a questionnaire concerning waste producing processes. This list did
not include garages or other small commercial establishments, unless they had
SIC Codes listed in the EPA National Pretreatment Strategy.
The completed application ultimately resulted in 182 permits being
issued to 130 firms (some with multiple discharges) on February 1, 1979.
However, it was necessary to review the ordinance standards as promised by
the Commission, and possibly revise those standards prior to issuing the
permits. Changes to the ordinance standards were based on developing two
tables of limits. One table would list the most critical concentration for
a particular pollutant chosen by comparing plant inhibition data (1), and
NPDES Permit requirements. This process would result in "protection criteria"
to satisfy Section 307 of the Act. This process is illustrated in Figure 1.
233
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TABLE 2. POTW NPDES COMPLIANCE SCHEDULE
Activity Number Activity
1. On or prior to , the permittee shall submit
the results of an industrial user (IU) survey in accordance
with 40 CFR 403.8 (f) (2) (i), including any IU's covered
under Section 301 (i) (2) of the Act. As much information
as possible must be obtained relative to the character and
volume of pollutants contributed to the PQTW by the IU's.
2. On or prior to , the permittee shall submit
a technical report acceptable to the Tennessee Division of
Water Quality Control which accurately characterizes the
wastewater influent to the POTW in terms of flow, compat-
ible and incompatible pollutants as well as upsets and/or
loading variations.
3. On or prior to , the permittee shall submit
a technical report acceptable to the Tennessee Division of
Water Quality Control which establishes the protection cri-
teria for the POTW in terms of interference, inhibition and
pass-through. Thus, this report must specify influent limi-
tations at the POTW for prohibited pollutants (as defined
by 40 CFR 403.5) contributed to the POTW by the IU's.
4. On or prior to , the permittee shall obtain
adequate legal authority to administer a pretreatment pro-
gram by adopting a Sewer Use Ordinance (SUO) acceptable to
the Tennessee Division of Water Quality Control for the con-
trol of discharges to the sewerage system of the City of
by all IU's.
5. On or prior to , the permittee shall submit a
summary report relative to the progress and direction of the
POTW Pretreatment Program. The scope of this report must
address two items: (a) Revisions to NPDES pretreatment com-
pliance schedule (on the basis that the POTW is justified
in not being required to have a complete pretreatment pro-
gram or more time is needed to complete activities than
originally anticipated). (b) Amendments to the pretreat-
ment grant, if applicable.
6. On or prior to , the permittee shall submit a
technical report acceptable to the Tennessee Division of
Water Quality Control which accurately accounts for all
pollutant sources. This report must contain a pollutant-
by-pollutant mass balance analysis of the sewerage system
showing the correlation of the industrial contributions
with that of actual influent POTW conditions .
234
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TABLE 2 (Continued)
Activity Number Activity
7 _ On or prior to , the permittee shall submit
a technical report acceptable to the Tennessee Division of
Water Quality Control which explains the design of a moni-
toring program necessary to implement the POTW pretreatment
program and to carry out the directives of the SUO.
8. On or prior to , the permittee shall submit a
list of monitoring equipment required by the POTW to im-
plement their pretreatment program and a description of
municipal facilities to be constructed for the monitoring
or analysis of industrial wastes.
9. On or prior to , the permittee shall submit
an evaluation of the financial programs and revenues sourc-
es necessary to implement their pretreatment program and to
carry out the directives of their SUO which is acceptable
to the Tennessee Division of Water Quality Control.
10. On or prior to , the permittee shall submit
a detailed description of the methodology used to issue
permits to the Ill's. This methodology must be consistent
with the provisions of their SUO and acceptable to the
Tennessee Division of Water Quality Control. (Where con-
tracts or joint powers of agreement are used substitute
the appropriate term in place of the word, "permit").
11. On or prior to , the permittee shall issue
all IU permits consistent with the provisions of their SUO.
12. On or prior to 30 days prior to submission of the POTW Pre-
treatment Program the permittee shall make available to the
public a copy of their draft submission. (The permittee
must comply with the requirements of 40 CFR Part 403.9 (d)).
13. On or prior to , the permittee shall submit a
request for pretreatment program approval (and removal
credit allowances approval, if desired).
Exception to Pretreatment Program Requirements
If the industrial user survey required by Activity 1 of the pretreatment
compliance schedule demonstrates that the POTW has no industrial user nor
will have an industrial user via Section 301 (i) (2), then the permittee will
be required to satisfy only Activities 1, 3 and 4 of the pretreatment com-
pliance schedule.
235
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The second table of standards (and more significant from an enforcement stand-
point) specified what levels could not be exceeded by a given industrial dis-
charge at the point it entered the City Sewer System. It is interesting to
note that these types of standards were called "optional" in a recent EPA
model ordinance. This, however, is misleading. Such standards are the only
practical means of enforcing discharge permits. By way of illustration,
notice that there is nothing "optional" about the standards in NPDES permits
for direct dischargers.
Each pollutant limit was developed through a mass balance of the pollu-
tant in the sewer system. The total load reported in the industrial permit
applications was compared to the observed pollutant load at the treatment
plant influent. A computer program was developed to perform these summations
and to account for the inventory of pollutants. Also, the observed pollutant
load at the influent was compared to the first table of the treatment plant
influent standards (the protection cirteria). Industrial Discharge Standards
were selected" for those pollutants which were causing or close to causing
violations to the POTW influent standard. The actual numerical limits were
selected by a combination of considering dilution in the sewer system by
"backing a standard up the pipe," and inspection of data from all dischargers
of the pollutant under consideration. In most cases it was possible to select
a cut-off point by this process for those industrial dischargers which had
high concentrations due to poor housekeeping and/or wasteful processes, and
who were causing most of the violations at the treatment plant. The remaining
standards were negotiated with the State Director and EPA. These standards
are more stringent than would have been calculated by the above procedure;
however, it was understood in the negotiations that as a better data base was
developed, and compliance with the plant's NPDES standards was achieved, the
discharge standards could be adjusted if found to be too stringent. Control-
ling the discharge of these pollutants also provides a factor of safety for
synergistic effects that may be causing some of the plant operating problems.
To protect industry from having to install pretreatment that may be de-
signed for more stringent standards than necessary, the City negotiated two
major timetables for industrial compliance. The first schedule which must be
completed by January 1, 1981, covered all pollutants currently exceeding the
plant influent standards as shown in Table 3. The second schedule must be
completed by January 1, 1983, and covers the remaining pollutants in the
Table of Industrial Discharge Standards. With these factors in mind, a re-
vised set of industrial effluent limits were developed. The limits shown in
Table 4 have been approved by the State and EPA and are considered adequate
in controlling the industrial discharges to the sewer. Note that numerous
pollutants have been dropped from this table. This was due to no control
currently being warranted because of low loadings presently experienced at
the treatment plant. However, the City has reserved the right to apply more
stringent limits, or to add additional limits, should this be necessary some-
time in the future.
236
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ORDINANCE PROTECTION CRITERIA
POLLUTANTS
Arsenic
Copper
Nickel
Silver
Figure 1.
NPDES PERMIT INHIBITION
DAILY MAXIMUM THRESHOLD
(mg/1) (mg/1)
1.0
0.4
3.0
0.05
Examples of the
0.1
1.0
1.0
5.0
Methodology for
24 HOUR FLOW
COMPOSITE
(mg/1)
0.05
0.4
0.5
0.05
Selection of the
INSTANTANEOUS
MAXIMUM
(mg/1)
0.1
0.8
1.0
0.1
Most Critical
Limits for Ordinance Standards.
TABLE 3. CRITERIA TO PROTECT THE TREATMENT PLANT
Parameter
Aluminum (dissolved)
Antimony
Arsenic
Barium
Boron
Cadmium
Chromium-total
Cobalt
Copper
Cyanide
Fluoride
Iron
Lead
Manganese
Mercury
Nickel
Phenols
Selenium
Silver
Titanium-dissolved
Zinc
Total Kjeldahl Nitrogen
Oil & Grease
Total Dissolved Solids
BOD
COD
S. S.
Influent Limit
15.00 mg/1
0.50 mg/1
0.05 mg/1
2.50 mg/1
1.00 mg/1
0.01 mg/1
1.50 mg/1
5.00 mg/1
0.40 mg/1
0.05 mg/1
10.00 mg/1
5.00 mg/1
0.10 mg/1
0.50 mg/1
0.015 mg/1
0.50 mg/1
1.00 mg/1
0.005 mg/1
0.05 mg/1
1.00 mg/1
2.00 mg/1
45.00 mg/1
25.00 mg/1
1,875.00 mg/1
A
*
A
237
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TABLE 4. 1978 INDUSTRIAL EFFLUENT LIMITATIONS
Maximum Maximum
Concentration Instantaneous
Mg/1 (24-hour Concentration
Flow Proportional Mg/1
Parameter Composite Sample) (Grab Sample)
BOD
COD
TSS
Arsenic
Cadmium
Chromium-total
Chr omium-Hexava 1 ent
Copper
Cyanide
Lead
Mercury
Nickel
Selenium
Silver
Zinc
Oil & Grease
(Petroleum and/ or
Mineral origin)
A
*
A
1.00
1.00
5.00
0.05
5.00
2.00
1.50
0.10
5.00
1.00
1.00
5.00
100.00
-
-
2.00
2.00
10.00
0.10
10.00
4.00
3.00
0.20
10.00
2.00
2.00
10.00
200.00
A comparison of the ranking of the Chattanooga standards with standards
for metals in other municipal ordinances from a study by Dietz (2) is shown
in Figure 2. For these metals it can be seen that the Chattanooga standards
are quite liberal. Yet, based on our research, they are sufficient to pro-
tect the treatment works. The significance is the methodology. The limits
for any given plant are subject to variation due to local conditions.
Locally, the impact of the new standards may be seen in Table 5, show-
ing a significant reduction in the number of industries which would be re-
quired to pretreat, and that the total flow which was subject to pretreatment
in the old standards has been reduced by two-thirds. It is estimated that
required capital expenditures will be cut in half.
The plant technical staff has determined that by the time industries
will have to begin compliance activities for the 1983 standards, several
major changes in the environmental situation will have occurred. First,
most of the National Categorical standards will have been published by EPA
as shown in Figure 3. As they are promulgated, they will administratively
supercede Chattanooga's ordinance standards for the pollutants and indus-
tries in each National Standard. (Industries subject to National Standards,
however, will still have to comply with the City standards if the local
standards are more stringent and/or if the ordinance controls pollutants not
covered by the National Standards). It should be clear from the previous
dissusion that the National Standards are not needed for environmental pro-
tection but are included in Chattanooga's program solely because of EPA ad-
ministrative requirements.
238
-------
Second, the data base at the plant on these pollutants is continually
expanding and there should be sufficient information available prior to the
first compliance date in the 1983 schedule to either confirm or revise the
industrial standards for pollutant levels that are not violating the plant
influent levels at the present time. This data base is being supplemented
by information generated from the "local credits" sampling program.
With the industrial and plant sampling programs well under way, the mon-
itoring staff conducted a thorough residential/commercial sampling program
to identify the pollutant loadings associated with those contributors. A one-
month residential and commercial wastewater survey was initiated in July
1978. The samples were analyzed by the city laboratory for all parameters
required by the ordinance. Table 6 shows the results of that sampling.
The values shown compare well with those previously listed in the liter-
ature. Also, no significant differences are noted for samples obtained from
a purely residential area to those collected from a mixture of residential
and commercial wastewater.
Because of concerns previously raised by industry, the POTW staff made
every effort to insure that those concerns were fairly addressed and that
the industrial community was involved in the decision making process. This
was accomplished through presentations to the Wastewater Appeals Board
(created in the 1977 ordinance) and to the Environmental Committee of the
Chattanooga Manufacturer's Association (CMA). The five member Board which
was made up of representatives of the industrial, economic, engineering and
legal segments of the community, and the CMA, worked closely with the POTW
staff for almost a year to develop the ordinance revisions. These were
finally drafted and accepted shortly after the long awaited Pretreatment
Regulations were published in June 1978. No objections were made to the
proposed standards once the mass balance study was completed and reported to
the CMA Environmental Committee. The main reason for this was that it was
obvious to all concerned that the City was only requesting controls and limit
levels that were logically related to plant operation and environmental pro-
tection. Additionally, a modified version of the exception clause provides
latitude to the Wastewater Appeals Board for flexibility in granting relief
from specific standards. To date, only two firms have requested this type of
relief. Both submitted reports, as required by the ordinance, which certi-
fied that good management practices for pollution control were in effect.
Various other factors such as impact on the POTW, whether the exception was
for toxic pollutants, the age of the equipment, water conservation, etc.,
were reviewed on a case-by-case basis by the Board.
The final draft revision of the ordinance was easily passed by the City
Commission when letters of endorsement were presented from the CMA, the State
of Tennessee, Region IV EPA, and the Appeals Board. This unanimous approval
prompted one Commissioner to remark that to have gotten agreement from such
diverse parties was, "only a little short of miraculous." This firmly under-
scored the value of prior coordination with all interested groups. The
ordinance is in the Appendix.
239
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Chattanooga
Limits
% Cities more "*"
Stringent
Number of
Cities in
Survey:
43
36
38
% Cities less
Stringent
Copper
(0.2mg/l-15mg/l)
Lead
(0.05mg/l-5mg/l)
Cadmium
(0.002mg/l-15mg/l)
Nickel
(O.lmg/l-15mg/l)
NEW
OLD
Figure 2. Graphical Comparison of Chattanooga Standards With Other Cities.
240
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Leather Tail!! ing
ecl i op hit I ng (pret real ment ) Fl na I
Text Iles
Timber Products
Petroleum He I 1 n i i
Paint and Ink
inorganic Chc'iul cais
St eain I'll oc:l ric
Decreasing
Aulu and Other Laundries
AppJ lcal>i 1 I ty
ol
Kx|i]osJvea, Soaps and Determents
Pharniaceut lea la
I'M ecr ropla t Jug
Ore Ml nin;',
Local
Ord i nance
Standards
Coal Mining, Foundrlea
Median lea 1 Products
ferrous Metals (7)
Coll Coating, Pul |) and Paper
Pest icicles
Organic Chemicals (1)
Plastics and Synthetic Materials.
Photograph! c Su|)|)l les
Iron and Steel, Porcelain L'nain., Copper Form.
Adlieslves and Sealants, Alunti
Fo rin i n u
I'll ectr Lea I Products
liattery Manufacturing (i)
Industries not assigned National Standards
J L
J U
1980
J L
1 - U
1981
Figuie '1. Uul al iontih i |> between City Standards and Schedule for National Standards
-------
TABLE 5. REDUCTION OF PRETREATMENT REQUIREMENTS
Number of Industries
Requiring Pretreatment
Flow Requiring
Pretreatment (MGD)
Pretreatment
required for:
Metals only
Metals (Oil
and Grease)
Oil & Grease
only
Old Limits New Limits
53 15
Old Limits New Limits
7.0 0.2
31
13
10
34
2.6
0.2
0.1
2.7
TOTAL
97
59
9.8
3.0
TABLE 6. RESIDENTIAL AND COMMERCIAL WASTEWATER CHARACTERISTICS
Parameter
Concentration (Mg/1)
Residential
Residential/Commercial
BOD
COD
TSS
NH -N
TKN
Phosphorus
Fluorides
Surfactants (MBAS)
Aluminum
Antimony
Arsenic
Barium
Boron
Cadmium
Chromium
Cobalt
Copper
Cyanide
Iron
Lead
Magnesium
Manganese
Mercury
Nickel
Phenols
Selenium
Silver
Strontium
Tin
Titanium
Zinc
250.000
600.000
290.000
21.000
35.000
10.000
3.100
9.800
1.100
0.001
0.001
0.051
0.210
0.002
0.011
0.001
0.120
0.010
2.100
0.026
6.100
0.039
0.001
0.019
0.020
0.001
0.008
0.029
0.010
0.240
0.400
240.000
520.000
280,000
23.000
26.000
11.000
2.300
10.800
1.020
0.001
0.001
0.046
0.300
0.002
0.024
0.001
0.100
0.010
1.700
0.028
5.900
0.050
0.001
0.015
0.040
0.001
0.016
0.049
0.010
0.370
0.330
242
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The City staff feels that the revised limitations placed on the indus-
trial discharges to the system will adequately protect the treatment plant
while requiring no unnecessary treatment by industry. This,therefore, will
satisfy the goals of the Clean Water Act. It should not be inferred that the
users "welcomed" these new restrictions. However, they at least understood
the importance of the City standards which were designed to protect the plant
operation.
Current Program
Staff and Organization
The present staff is organized as shown in Figure 4. This structure
should have sufficient flexibility to expand or change as the program
matures through the major stages of data gathering, pretreatment enforce-
ment, verification monitoring, and updating of standards and rate schedules.
While most af the original end-of-pipe sampling was performed by two two-man
crews, only one crew is presently conducting verification sampling at this
time due to personnel turnover. A second crew will be activated soon to
enable the program to sample all permitted discharges once a year as required
in the EPA program and to maintain the same level of responsiveness for veri-
fication sampling and local credits sampling.
Permit and Ordinance Enforcement
The Industrial Wastewater Discharge Permits are the most visible exten-
sion of the Industrial Waste Ordinance and the authority of the Superinten-
dent. The permit sets forth self-monitoring requirements for each industrial
discharger as well as a compliance schedule for pretreatment if standards are
exceeded. A permit may also contain other special conditions depending on
the nature of the discharge. Ninety-five (95) of the first City permits had
some kind of pretreatment compliance schedule.
Monitoring industrial discharges for compliance is a critical part of
the program, yet it would have been impossible to carry out adequately with
the limited City staff. Therefore, it was decided that the periodic monitor-
ing would be carried out by the affected industries, with the City conducting
annual unannounced verification monitoring as described in 40 CFR 403. While
this sounds like "leaving the fox to guard the hen house," in reality no
cases of data falsification have been detected. Additionally, many indus-
tries seem to have become more conscious of, and responsive to their waste-
water violations. Some of these violations were a result of poor housekeep-
ing. Eleven companies that have corrected their housekeeping problems are
now in compliance.
The decision to require self-monitoring for a given pollutant is based
on whether that pollutant is present at levels above the ordinance limit, at
levels below the ordinance limit but above domestic levels, or at levels be-
low domestic waste. Monitoring is classified in categories for the purposes
of enforcement, surveillance, or not required, respectively. In addition,
surcharge monitoring may be required for BOD^, COD, and Suspended Solids.
243
-------
t-o
-(>
-p-
[cm P.NCTNTI:R|--
SECRETARY
jCOMMISSIONER j
I.S.S.
SUPERINTENDENT
COORDINATOR
TNIWSTIM'AI, WAS'l'i: PRCX1RAM
d HIT OPERATOR
BKAINIikl)
Cl HIT OPERATOR
MOCCASIN HI:ND
PUMP .STATION
OPERATION
i L',.iL ion Cli.irl
-------
Each class of monitoring has an associated frequency depending on the size
of the discharge as shown in Figure 5.
Forms were developed by the staff for making monitoring reports, with
the method of analysis specified on the form for each parameter (as shown in
the Appendix). This eliminated questionable or inadequate "kit" type analy-
sis. The City also conducts monitoring at the request of a discharger to
verify that compliance standards have been achieved. Monitoring can be re-
quested by a discharger in addition to self-monitoring but not in lieu of
permit requirements, and this monitoring is charged to the industry at a
base rate set in the surcharge ordinance.
Local Credits Monitoring
The administrative concept of local credits first appeared in 40 CFR
Part 128, which preceded Part 403. This concept was only allowed to be
used in those cases where "substantial" removal was documented and when the
POTW was actually designed to remove the pollutant under consideration.
Shortly after the publication of Part 403 in June 1978, the City of Chatta-
nooga initiated a program as described in Section 403,7 for gathering data
to support a local credits request for the Moccasin Bend Treatment Plant.
That section defines consistent removal as "reduction in the amount of a
pollutant or alteration of the nature of a pollutant in the influent to a
POTW to a less toxic or harmless state in the effluent which is achieved by
the POTW in 95% of the samples taken when measured according to the proced-
ures set forth in Section 403.7 (c)(2)." Essentially, these procedures were
directed towards obtaining samples representative of yearly and seasonal con-
ditions, and require a minimum of 12 discrete influent and effluent samples
to be composited each day for three consecutive days each sampling period.
The City sampling crews have collected samples for information on con-
sistent removal during seven quarterly sampling periods with each period
seven days long and having 24 sample collections per day. Four locations
were sampled each hour as shown in Figure 6 which resulted in a total of 96
discrete samples collected per day. Effluent samples were taken nine hours
later than influent samples to allow for the plant hydraulic detention time.
The sampling and analysis was documented exactly in accordance with the pro-
cedures outlined in Section 403.12 (n) for 31 pollutants of interest.
Under the current procedures and definitions in 40 CFR 403, the City
could not request local removal credits. Each toxic pollutant had at least
two days that showed no removal or a higher level of pollutant in the
effluent than in the influent. This meant that the 95% confidence level
could not be met to verify "consistent removal."
Failure to achieve this "consistent removal" by the EPA standards at
the Moccasin Bend Plant was attributed to the fact that the seven-day sampl-
ing period did not allow for the 21-day detention time in the anaerobic
digesters. Since most of the toxics discussed in the Chattanooga study were
metals, and therefore conservative in nature, it is expected that the re-
cycle load from the digester caused fluctuations in the metal concentrations
downstream from the influent sampling point that were unrelated to the
245
-------
ro
-P-
[ntlusl rid!
liiacl urge
Voluiiiu
Greater
than
100,000 g[«.l
1 00,001) g[«J
l:o
!jO,0()0 jy«.1
50,000 gixj
to
10,000 gpd
10,000 gj.d
it)
UOO ^1,1
Itsa
1 Iklll
1)00 J..H1
Sample
•IVI*
t:
sv
se
i:
sv
so
V.
sv
sc
L:
sv
sc
i.:
sv
sc
SAMPUNi; um:i Hi.viirnl (I'l, SHI v<: i I 1.. 1110= (SV), and
-------
influent load on the day sampled. Nonetheless, averages of the data from
this study and averages of 130 additional days show an overall removal of
these pollutants. Additionally, metals have been shown to accumulate in the
primary sludge solids indicating removal of metals from the effluent.
The experience of the local credits program at Moccasin Bend is not
unique and the situation in Chattanooga would likely be repeated in virtually
any plant having a unit process with a detention time longer than the re-
quired sampling period. "Negative removals" also have showed up in EPA's
study of 40 POTW's (3). Yet, many of these plants would also be able to
show long term removals. The problem of getting permission to apply for
local credits has been complicated by: 1) the requirement to have an approved
pretreatment program; 2) the requirement to have the year-long local credits
study completed by the time a POTW applies for its program approval (or be
forced to wait until its permit is reissued); and 3) the unresolved question
of periodic reverification of removals. These difficulties make it unlikely
that any POTW would succeed in demonstrating removals or that many would
even attempt to take advantage of the relief granted by Congress in the 1977
Clean Water Act Amendments. This statement was verified by the negative re-
action to local credits expressed by POTW managers at the recent AMSA Nation-
al Pretreatment Conference. The problem seemed to be one of how EPA de-
fined the program rather than whether or not removals were actually being
achieved.
Recently the draft revisions of 40 CFR Part 403 became available. These
revisions published in October 1979 provided for an alternate methodology to
calculate removals based on 12 monthly samples. The City staff feels that
the 47 days of sampling checked so far provide a superior data base for its
local credits request. Also, discussions with EPA's Office of General
Counsel have indicated that the City may be able to use the data collected on
the "raw" and "treated" sample as a basis to claim removals when the new
plant expansion is complete. The reason for this is that this set of data
would be more representative of a plant which has a system to dispose of the
waste activated sludge. Removals calculated by this revised method are
based on an average of the lowest 50% of the data points or the lowest 6
data points (whichever number of points is greater). If there are less than
8 usable samples, the Approval Authority may approve alternate means to cal-
culate "consistent removal."
The results for 13 of those pollutants which were on the list of 129
toxics are shown in Table 7. Based on these results, the City has made the
first application in Region IV for verification of consistent removal. The
State of Tennessee has already approved this request. If Part 403 is modi-
fied as proposed, then the City will be able to base a request for local
credits on the consistent removal already documented without going through
another lengthy technical review. Time is most critical at this point be-
cause industries are already having to begin planning for pretreatment design
and they need to know as soon as possible what credits will be available for
the program to be of any worth. The foregoing demonstrates that the City of
Chattanooga is strongly committed to local credits. However, it should be
247
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RECYCLE
GRIT
SLUDGE
WASTE ACTIVATED
SLUDGE
INFLUENT FROM
CHATTANOOGA
l) INFLUENT SAMPLE
BYPASS
INFLUENT
METER
I
GRIT
REMOVAL
RAW SAMPLE
PRIMARY
I SEDIMENTATION
SETTLED SAMPLE
AERATION SYSTEM
TREATED SAMPLE
EFFLUENT
METER
(14 ) EFFLUENT SAMPLE
TENNESSEE RIVER
Figure 6. Local Credits Sampling Diagram
248
-------
remembered that this complicated program, which costs about 20% of the pro-
gram budget, would not even be needed if Categorical Standards were not re-
quired in Chattanooga.
Funding - User Charges and Surcharges
Up to January 1, 1980, the pretreatment program was funded completely
by user charges. However, the City Code has been amended to include sur-
charges, ICR (Industrial Cost Recovery) and other specific charges as re-
quired in the Construction Grant Regulations (40 CFR Part 35). The prin-
cipal source of new revenue will be from high-strength surcharges; this
revenue is estimated at over one-half million dollars, (about 20% of the 0
and M budget for 1980). This will pay for increased operation and main-
tenance costs to treat excess BOD,-, COD, and Suspended Solids. The increased
costs also include the costs of the pretreatment program as shown in Table 8.
Some industries questioned surcharging for both BOD^ and COD. In actuality
the BODcj and COD- charges were calculated separately and do not constitute
double charging. An industry with a relatively compatible waste would not
notice the difference in its bill if the rate structure had been set up for
BOD5 alone. However, an industry discharging a waste with a high COD to
BOD_ ratio, or an otherwise incompatible waste will pay more because of the
difficulty of treating that type waste. An interim rate structure is shown
in Table 9 which was developed by the POT¥ staff. A final rate structure is
being developed under an EPA contract by the City's consultant engineers.
Federal Pretreatment Program
The previously described activities of ordinance revision and sampling
programs were further complicated by the uncertainties associated with the
requirements of Section 307 (b) and (c) of PL 92-500 and the Clean Water Act
Amendments. The 40 CFR Part 403 General Pretreatment Regulations, which im-
plement Section 307, were first proposed in February 1977, barely a month
after the passage of the first comprehensive ordinance. As stated earlier,
doubts were cast upon the usefulness and applicability of the 1977 ordinance
by several groups with a vested interest in its contents.
The City agreed that the ordinance should be revised but felt that the
most prudent course to follow would be to wait until Part 403 was promulgat-
ed in its final form. The 18-month delay until the final rule was published
proved to be an agonizing period of frustration which strained the patience
and credibility of all participants in the local program development. During
this period, the City was actively gathering data to support needed limita-
tion revisions as described earlier.
The administrative requirements and content of the 403 local programs
closely paralleled, and added to the requirements of the Step II Grant con-
ditions for Chattanooga discussed earlier. Most of the tasks required for
an approved 403 pretreatment program, particularly the development of the
sewer ordinance, has already been undertaken in order for the City to com-
ply with the special grant agreements.
249
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ro
Ol
o
TABLE 7. SUMMARY OF
LOCAL CREDITS SAMPLING AS OF DECEMBER 1979
Toxic
Parameter
Antimony -H-
Arsenic ++
Cadmium
Chromium
Copper
Cyanide ++
Lead
Mercury -H-
Nickel
Phenol
Selenium -H-+
Silver
Zinc
Number of
One Week
Sampling
Period*
5
5
6
5
6
6
6
5
6
6
5
5
6
Number of
Data Point **
31
30
41
35
42
16
42
24
42
25
—
34
42
Overall
Average
% Removal ***
31.5
—
54 . 1
55.8
70.7
—
66.7
—
40.2
61.8
—
60.1
62.8
403.7
% Removal
July ,78/Oct. 79 +
—
—
34.6
31.7
54.6
—
53.2
—
18
35.8
—
35.5
43.6
403 . 7
% Removal
Latest 4
Quarters
—
—
29.1
24.9
46.5
—
49.6
—
14.9
20.9
—
39.2
50.0
* Sampling was performed for one seven^day week per calendar quarter.
** Number of valid data points as determined by 40 CFR 403.7; some were discarded because -they were
below the limit of detection; also not all parameters were measured for 7 days.
*** Arithmetic mean of percent removal between sampling point #2 and //3.
+ Criteria as proposed on October 29, 1979.
++ Averages showed a
which is greater than the sevens-day monitoring period.
•I I I All Selenium concentrations were below the limit of detection.
"negative" removal possibly due to digester recycle having a 21-day detention time
-------
TABLE 8. PROJECTED ANNUAL PRETREATMENT PROGRAM COSTS (1980)
Activity Lab Analysis Sampling Equipment Administration Total
Industrial Sampling and Compliance Monitoring
(183 permits checked avg. 2 days/year) $42,441 $18,985 $6,578 $16,100 $84,104
Local Credits Sampling in*-plant
(7 days/quarter at 4 plant locations) $12,988 $ 7,448 $ 767 $12,100 $33,303
Quality Control $ 5,543 — $ 330 $ 3,400 $ 9,273
Permit Writing, Appeals, Compliance Checking,
Data Processing, Typing, Misc., Administra--
tion — — $4,392 $32,400 $36,792
TOTAL $60.972 $26.433 $12,067 $64.000 $163.472
-------
Additional tasks required by Part 403 and included in the 1978 ordi-
nance were:
1) Development of procedures to notify industrial contributors of their
responsibilities and to notify them of applicable local and National
Pretreatment Standards. Although not required of the City prior to
EPA program approval, the POTW staff has been promulgated or pro-
posed. This type service has helped to enhance the rapport between
the City and the industrial dischargers and is relatively simple to
accomplish by using a computer program to sort for-SIC Codes.
2) Compliance with public participation requirements in the enforce-
ment of National Standards to include annual public notice of in-
dustial users not in compliance with the program.
TABLE 9. SCHEDULE OF INTERIM SEWER RATES
Meter Rates
For the first 50,000 gal.
For the next 50,000 gal.
For the next 100,000 gal.
For the next 250,000 gal.
For the next 300,000 gal.
For the next 500,000 gal.
For the next 750,000 gal.
For all over 1,000,000 gal.
For all over 3,000,000 gal.
Pounds of BOD over 300 mg/1
Pounds of COD over 600 mg/1
Pounds of Suspended Solids
Uniform 0 & M
User Charge
$0.181
$0.181
$0.181
$0.181
$0.181
$0.181
$0.181
$0.181
$0.181
SURCHARGE RATES
over 400 mg/1
Service Charge
$1.028
$0.885
$0.751
$0.761
$0.618
$0.565
$0.508
$0.490
$0.293
Total
$1.209
$1.066
$0.932
$0.942
$0.799
$0.746
$0.689
$0.671
$0.474
,$0.0105124
,$0.0066148
,$0.0143145
252
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The ordinance controls originally required by the grant have been struc-
tured to have the legal authority to implement the formal pretreatment pro-
gram called for by the regulation. In many cases this was accomplished by
incorporating the language from the Federal Register directly into the ordi-
nance.
A major flaw in the current 1978 ordinance is the lack of any signifi-
cant civil or criminal penalty for violators as required in Section 403.8.
In Tennessee, local governments do not have the authority to require a fine
greater than $50.00 for each ordinance violation. When the city makes for-
mal application for program approval, it will rely on a provision of Tennes-
s ee law authorizing the imposition of higher civil penalties at the State
level as evidence of preemption. Additionally, the City attorneys have dis-
cussed this problem with State representatives and believe that, since the
Tennessee legislature has traditionally been slow to act in the environment-
al area, that EPA pressure will be needed to achieve immediate results. If
this cannot be accomplished, the attorneys believe that all of the local
governments required to develop pretreatment programs in the State could
successfully petition the Tennessee legislature for relief (4).
Enforcement of Chattanooga Ordinance Standards against industrial users
outside the City limits is another significant problem since sewer dis-
charges are received from across city, county, and state lines. So far, no
users outside the City have challenged the legal validity of these permits.
This is attributed to basic acceptance by industry of the importance of dis-
charge control, and the fairness and reliability of the current ordinance
standards. However, the City is working on developing contracts with the
affected industries to cover this deficiency.
Other municipalities required to tie onto the Chattanooga system as
part of the area-wide 208 plan will sign contracts which include a commit-
ment to adopt the essential elements of the Chattanooga City Code. The POTW
staff feels that eventually the system will be converted into a district
with the power to pass its own ordinances. This approach will be much less
cumbersome than the present system.
National Pretreatment Costs
The EPA estimated monitoring costs for municipalities and industries,
as reported in the supplementary information preceeding the final
regulation, were inadequate and misleading. The EPA estimated total cost
(adjusted for the Moccasin Bend Plant being larger than the "average" plant
of 16-33 MGD) for the 1979-1983 period was $143,451. This represented the
net local share of the costs estimated by EPA after federal funding. Based
on experience in the City of Chattanooga, the monitoring costs alone for one
year will be more than the EPA adjusted estimate for 5 years of implementing
the 403 requirements. The actual cost to the City for the initial sampling
was $161,854 for 70 discharges from 45 of the largest industries. By today's
guidelines on construction grants from EPA, this type of end-of-pipe sampling
is being discouraged, however, the POTW staff feels that it could not have
dealt with the enormous magnitude of the pretreatment problem in Chattanooga
253
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without the high confidence level stemming from data gathered in the City's
sampling program.
The industrial community will also be hit hard. One consultant esti-
mated that industrial monitoring costs in Chattanooga will be about $780,000
per year or about $6,000 annually per industry to accomplish the minimum
sampling required by the City ordinance and permits. Table 10 shows that
for the Electroplating Standards, the analysis costs alone will triple with-
out concurrent increased environmental or administrative benefits,
Problems with National Categorical Standards
EPA miscalculated the cost of compliance with Part 403 by a factor of
13 with their estimated cost of $460 per year per industry. For this reason
the City feels that the EPA needs to make a very thorough analysis of the
environmental benefits versus the cost of adding the National Categorical
Standards to a program which already is likely to cost much more than its
proposed price tag. EPA did not attempt to estimate the cost to industry of
actual compliance with the National Categorical Standards in Part 403. The
City staff can appreciate the fact that estimating this cost before publica-
tion of the categorical standards was a difficult task. However, this rep-
resents a significant hidden cost of the overall pretreatment program. It
would have been interesting to see the results of an Economic Impact State-
ment if EPA had been required to evaluate the full national cost of the pre-
treatment program and strategy. A study by the State of Tennessee (5) esti-
mated that the $100 million mark was greatly exceeded (which would have
made an Economic Impact Statement mandatory).
The present inflexible, cumbersome, costly, and difficult program of the
National Pretreatment Strategy was not defined by Congress. However, the
basis of its patch work of consent decrees, court decisions, and informal
agreements between EPA and environmental groups is nonetheless rooted in the
vague wording of Section 306 and 307 of the Act. The main thrust of this
Strategy was determined primarily by Court action. Cities and POTW authori-
ties generally had little input into this strategy because of the lack of
technical knowledge and money at that time. The strategy direction largely
came from environmental activist groups who don't have to run the programs
or pay for them. Ironically, municipalities which are the keystones in this
program and are the most logical enforcement agencies were not made an
integral part of the decision making process.
The major argument used by EPA to support the national standards is
"Parity." However, this argument fails in practice, since water quality
standards take precedence (properly so) for many direct dischargers who may
otherwise be regulated by a less stringent national standard. Thus, the
primary concern for direct dischargers is really with controlling the
pollutant load to the stream. This is also the most logical approach.
Since parity is actually invalid, then it is unreasonable to force indirect
dischargers to meet standards based on this concept. This is most signifi-
cant in those cases where there are good local programs which are structured
to meet the intent of the Act, and that control the pollutant load to the
stream, which is the basic objective in the first place.
254
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TABLE 10. ANNUAL INCREASE IN INDUSTRIAL SELF - MONITORING ANALYSIS COSTS
DUE TO EPA NATIONAL STANDARDS FOR ELECTROPLATERS
Industry Flow Existing Permit Permit w/National Difference
gpd $ Analysis Standards, $ Analysis* $
M
Ln
Ln
250,000
149,000
47,240
5,180
3,315
1,000
600
TOTAL
972
5,148
294
358
150
52
2,819
$9,793
5,076
26,354
1,658
879
671
580
3,223
$38,441
4,104
New Compliance
Requirements
none
21,106 Zn.CN.Cujtotal metals
1,364
521
521
528
404
$28', 648
none
none
none
none
none
*Based on Commercial Lab Rates
-------
As the National Standards are being proposed, the same inequities re-
ported by Patterson (6) are again being repeated. A brief comparison in
Table 11 between the Electroplating Standards and the Textile Standards for
Chromium, Copper and Zinc (while not as extreme as the "thousand fold"
difference for Arsenic reported by Patterson) nonetheless reflect a differ-
ence in discharge standards for the same pollutant that is unrelated to
treatment technology. These differences are also apparent between standards
for dischargers of the same type but of different sizes, as in the Electro-
plating Standard. Whatever happened to "parity" here?
Proposing fundamental changes to the Pretreatment Strategy to EPA has
been, and will be fruitless because the Agency is bound by the above de-
scribed network of suits and decisions, and its own bureaucratic inertia.
The only avenue of change, then, is through Congressional action to clarify
and redefine the Act and the National Strategy in light of the lessons
learned in the initial stages of the Pretreatment Program. To achieve this
end, Chattanooga has approached its Congressional delegation and received
a favorable response, and encourages other municipalities to do likewise.
The first goal of this action is to obtain a moratorium on the compliance
dates for the National Standards until municipal local programs are function-
ing. Those programs that demonstrate that the main goals of plant and en-
vironmental protection in Section 307 of the Clean Water Act can be achieved
by local standards should be incorporated into those POTW's NPDES permits in
such a manner to allow those cities the authority to operate independently
of the National Categorical Standards. Such independent operation should be
licensed only so long as the POTW control authority continues to meet its
NPDES permit requirements and sludge criteria.
This approach should provide a positive driving force to encourage
municipalities to develop local programs and to operate their POTW's as
efficiently as possible. It will also focus attention on insuring that NPDES
permits are comprehensive enough to include standards that are directly re-
lated to water quality protection. Publication of proposed water quality
criteria in 1979 (7) for the 65 toxics makes this goal realistic. Finally,
these changes should help to dispel the reluctance of State and local agen-
cies to take on the program as it is presently structured, and to provide
those agencies with positive incentives to convert the national goals into
viable programs.
256
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TABLE 11. COMPARISON OF PROPOSED TEXTILE PRETREATMENT STANDARDS
WITH THE FINAL ELECTROPLATING PRETREATMENT STANDARDS
Industrial Flows
Greater
Than
10,000 gpd
Less
Than
10,000 gpd
Pollutant
Chromium
Copper
Zinc
Chromium
Copper
Zinc
Textile
Daily
(nig /I)
0.9
0.9
1.8
0.9
0.9
1.8
Mills
30 day
(nig /I)
0.5
0,5
1.0
0.5
0.5
1.0
Electroplating
Daily 30 day
(mg/1) (mg/l)
7.0 2.5
4.5 1.8
4.2 1.8
no limits
no limits
no limits
257
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REFERENCES
1. Federal Guidelines; State and Local Pretreatment Programs. EPA-430/9-76-
017a, U.S. Environmental Protection Agency, Washington, B.C., 1977^
p. 179.
2. Dietz, J.C., and Dietz, J.D. A Rationale for Pretreatment Standards for
Industrial Discharges to Publicly Owned Treatment Works. In: Proceed-
ings of the 33rd Industrial Waste Conference, Purdue University, Indiana,
1978. pp. 121-127.
3. Denit, J. EPA's Forty Plant POTW Toxic Survey. In: Proceedings of the
National Pretreatment Symposium, AMSA, Duluth, Minnesota, 1979. pp. 102-
116.
4. AMSA. Pretreatment Program Implementation: Can It Really Be Done?
Washington, D.C., 1979.
5. O'Dette, R.G., and Kurz, G.E. The State of Tennessee Pretreatment
Position Paper. Nashville, Tennessee, 1977.
6. Patterson, J.W. Technical Inequities in Effluent Limitations Guidelines.
Journal Water Pollution Control. 49(7): 1586-1590, 1977.
7. EPA. Water Quality Criteria. In: Federal Register, Washington, D.C.,
1979. pp. 15926-15981, 43660-43697, 56628-52629.
258
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PB83-142323
INVESTIGATIONS ON THE SUITABILITY OF VARIOUS
PESTICIDE MANUFACTURING WASTEWATER FOR
DISCHARGE TO MUNICIPAL WASTE TREATMENT FACILITIES
E. C. Monnig*
TRW
Environmental Engineering Division
Research Triangle Park, N. C. 27709
L. W. Little
L.W. Little Associates
P. 0. Box 10035
Raleigh, N. C. 27605
R. Zweidinger
Research Triangle Institute
Research Triangle Park, N. C. 27709
ABSTRACT
The biological treatment of wastewaters from the production of atra-
zine, carbaryl, dazomet, dinoseb, glyphosate, maneb, mancozeb, and oryzalin
is discussed. Data are presented indicating that the mechanism of removal
during biological treatment of volatile organics such as toluene probably
involves significant volatilization. Data are presented on the use of
activated carbon as a pretreatment to biological treatment. A final example
is noted regarding the difference between ozonating a pesticide in a pure
solution and a pesticide in a mixed wastewater.
INTRODUCTION
The pesticide industry includes the manufacture of approximately 300
active ingredients at 139 manufacturing sites across the country (Kelso,
1978). The total U.S. production of pesticides amounted to 1.4 billion
pounds in 1974 (Kelso, 1978). The industry is highly diversified. In
1974, 205 of the active ingredients were manufactured by single producers,
though this trend is changing as the patent rights on several important
products expire.
Discharges from pesticide manufacturing sites are regulated under
section 301, 304, 306, and 307 of P.L. 92-500 (Federal Water Pollution
^Research conducted at Research Triangle Institute and supported by EPA
contracts 68-02-2612 and 68-02-3688.
259
-------
Control Act Amendments or the "Clean Water Act"). The focus of concern in
these discharges has been on three areas: traditional parameters including
BOD, COD, TSS, and pH; the 129 so called "consent decree priority pollu-
tants"; and the pesticide concentrations.
Regulations promulgated thus far in conjunction with Best Practical
Treatment (BPT) standards reflect in large measure the current state of
information on methods for treating the parameters of interest and methods
for analyzing the efficiency of treatment methods for pesticide manufactur-
ing wastewater.
Based on availability of treatment methods and analysis methods, the
pesticide industry was broken into several groups during the promulgation
of BPT standards. A group of pesticides or pesticide classes was excluded
from all regulation (see Table 1). A second group of 49 pesticides was
regulated for BOD, COD, TSS, pH, and pesticide concentration (see Table 2).
All other pesticides not listed in the first two categories were regulated
with reference to BOD, COD, TSS, and pH except that organometallics were
assigned a no-discharge status.
Given the need for methods of treatment and analysis of pesticide
wastewaters, several EPA research laboratories have been actively supporting
research in these areas. This report highlights research supported by
the Industrial Environmental Research Lab, RTP-NC as it related to treat-
ment of pesticide manufacturing wastes in municipal waste treatment systems.
BIOLOGICAL TREATMENT
The studies were designed in part to investigate the ability of a
municipal waste treatment system, as modelled by bench-scale activated
sludge units, to treat various pesticide manufacturing wastes. The
efficiency of treatment was determined by measuring traditional parameters
such as COD, ammonia, solids levels, as well as pesticide concentration
and break-down products before and after treatment. Toxicity of wastes
before and after treatment was monitored by algal assays (Selenatrum
capricornutum) and with daphnia or fathead minnows.
The bench-scale unit used in these studies is described by Swisher
(1970) and is shown in Figure 1. The treatment efficiency of this smaller
units was found to give very similar results to a larger unit (4-5 liters)
developed by the Organization of Economic Cooperation and Development (OECD)
for studies on biodegradation of surfactants. This larger unit is depicted
in Figure 2.
All the studies have involved actual pesticide manufacturing wastes
which were collected at the manufacturing facility prior to any treatment.
The samples were all collected from single manufacturing process waste-
streams. The pesticides wastewaters investigated thus far have included
atrazine, carbaryl, dazomet, dinoseb, glyphosate, maneb, mancozeb, MSMA,
and oryzalin. It would not be possible here to give complete details on
each of these studies. Several reports have been or will be published on
these studies and are listed in the bibliography; however, general and
260
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Table 1 Pesticides and Classes of Pesticides Excluded from BPT Regulations
Allethrin
Benzyl benzoate
Bilphenyl
Bisethylxanthogen
Cholorophacinone
Coumafuryl
Dimethyl phthalate
Diphacinone
Endothall acid
EXD (Herbisan)
Gibberellic Acid
Glyphosate
Methoprene
Naphthalene acetic acid
Phenylphenol
Piperonyl butoxide
Propargite
1,8 Naphthalic anhydride
Quinomethionate
Resmethrin
Rotenone
Sulfoxide
Sodium phenylphate
Triazine compounds (both symmetrical
and asymmetrical)
Warfarin and similar anticoagulants
261
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TABLE 2. PESTICIDES REGULATED FOR
BOD, COD, TSS, pH AND PESTICIDE CONCENTRATION
Aldrin
Aminocarb
Azinphos methyl
Barban
BHC
Cap tan
Carbaryl
Chlordane
Chlorpropham
2,4-D
ODD
DDE
DDT
Demeton-0
Demeton-S
Diazinon
Dicamba
Dichloran
Dicof ol
Dieldrin
Disulf oton
Diuron
Endosulf an
Endurin
Fenuron
Fenuron-TCA
Heptachlor
Lindane
Linuron
Malathion
Methiocarb
Methoxychlor
Mexacarbate
Mir ex
Monuron
Monuron-TCA
Neburon
Parathion ethyl
Parathion Methyl
PCNB
Perthane
Propham
Propoxur
Siduron
Silvex
SWEP
2,4,5,-T
Trifluralin
Toxaphene
262
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IFFLUEKT
EFFLUENT
eOLUCTION
Figure 1. Diagram of Swisher Activated-Sludge Unit.
263
-------
Air
Effluent
Collection
Figure g, Diagram of O.E.C.D. Activated Sludge Unit.
264
-------
summary statements can be made.
The pesticide concentration of the wastestreams from the manufacture
of carbaryl, maneb, mancozeb, and dazomet could be degraded within the
constraints of a municipal treatment system. Dilution factors ranged from
0.1 to 10 percent in municipal wastewater. In addition, the associated
organics in these wastewaters and the municipal wastewater were also
readily degraded as measured by the COD test.
It is interesting to note that the half-lives of these^pesticides in
the soil range from 6 hours to 60 days depending of conditions. Qualitative
predictions of the effect of biological treatment can sometimes be made
based on data on the fate of these pesticides in the soil. Data relative
the fate of a pesticide in the soil are now typically compiled during the
registration procedure and can be accessed through EPA's Office of Pesticide
Programs or through the manufacturer if they are not in the open literature.
Two herbicides were relatively unaffected by biological treatment yet
did not seem to interfere with biological processes. Glyphosate, at con-
centracions from 25 to 100 mg/L, was only partial removed during biological
treatment (40% removal). However, COD of the wastewaters was reduced as
much as 89% during biological treatment. Atrazine concentrations from 1
to 60 mg/L showed only partial removal during biological treatment (20%).
However, the atrazine wastewater did not seem to interfere with the
biological treatment of municipal wastewater.
The dinoseb and oryzalin wastewaters were both highly concentrated
with COD's as high as 14,500 and 45,000 mg/L, respectively. Both wastes
had high dissolved solids, 280,000 mg/L and 73,000 mg/L, respectively.
Both wastes showed a high tendency to disrupt biological treatment even at
dilutions as low as 1 ml/L in municipal wastewater.
Even in cases where municipal biological treatment of pesticides
wastewaters seems feasible, several provisos should be noted. The
ethylene-bis-dithiocarbamate pesticides such as maneb and mancozeb pro-
duce ethylene thiourea as a breakdown product which is a suspected thryoid
carcinogen. Dazomet produces methylisothiocyanate as a breakdown product.
While both ethylene thiourea and methylisothiocyanate are relatively short
lived in soil and water (half lives on the order of days), they have
potential effects that should be monitored.
Apparent interference with nitrification processes was also noted
in the treatment of mancozen, dazomet, and carbaryl wastewaters. The
dazomet concentrations were reduced >95% at dilutions of 1 part dazomet
wastewater to 100 parts municipal wastewater. However, at dilutions of 1
to 1000 in municipal wastewater, the dazomet wastewater reduced nitrification
by as much as 50%. This effect is probably due to the presence of methyl-
isothio-cyanate which has been shown to inhibit nitrification by 75% at
concentrations as low as 0.8 mg/L. (Tomlinson, 1966). Similar patterns
were exhibited for maneb-mancozem and carbaryl wastes, depending on con-
centration.
265
-------
Many of the pesticide wastes studied contained substantial quantities
of volatile organic compounds including acetone, toluene, and formaldehyde.
The fate of these compounds in biological treatment systems has been the
subject of some question. Based on results obtained during our studies it
would appear that during biological treatment volatile organic compounds
of low water solubility may be removed primarily through air stripping
rather than biological degradation.
Where appropriate, an air-stripping control was run during our studies.
The industrial waste was mixed at the appropriate dilution with distilled
water instead of municipal wastewater. The mixture is then pumped through
a biological treatment unit which contains distilled water instead sludge.
COD and the appropriate compounds are analyzed in the influent and effluent.
Table 3 includes data on toluene concentration in carbaryl wastewater before
and after air stripping. Mere exposure of a sample of diluted wastewater
(10% in DIW) to open air for 24 hours reduced toluene levels from 16 mg/L
to 0.9 mg/L. Pumping through the biological treatment unit further reduced
concentration to 0.1 mg/L. More water-soluble compounds such as formaldehyde
and acetone show a less consistent pattern. Additional research will be
required to determine these mechanisms of removal.
CARBON PRETREATMENT
Given the relatively refractory nature of most pesticides, removal of
this component before discharge to a POTW will probably be required. One
possible method for pretreatment is the use of activated carbon as a
selective filter. Because most pesticides are relatively high-molecule
weight compounds with low water solubility, they may be adsorbed prefer-
entially onto activated carbon relative to more water-soluble organics. The
use of this technique was demonstrated with a combination of dinoseb and
atrazine wastes.
The waste in question contained effluent from an atrazine process
(30 mg/L atrazine) which was contaminated with some washwater from a
dinoseb manufacturing process (5 mg/L dinoseb). This wastewater was
treated in a carbon column 2.5 cm in diameter which was filled to a height
of 45 cm with a slurry of 100 grams (dry weight) of carbon. The bed volume
of this column was 221 mL. Dinoseb-atrazine composite waste (pH unadjusted)
was pumped through this column at a rate of 13 mL/min (0.63 gal/ft^/min).
A total of 105 bed volumes (23.2 L) was pumped through the column.
No dinoseb or atrazine was detected at any point in the effluent from the
carbon column. The rise in COD levels with increasing bed volumes followed
a sigmoid pattern as presented in Figure 3. The COD of bed volumes 81-105
was approzimately that of the untreated sample. In a full scale version
of this system, the carbon which has been expended in treating the dilute
dinozeb-atrazine waste is then used to treat the concentrated dinoseb
wastestream referred to above. Because the quantity of a dinoseb sorbed
to carbon is a function of the concentration in solution, very high loadings
are achieved. This carbon treatment can reduce dinoseb from 800 mg/L to
less than 20 mg/L in the concentrated dinoseb waste. COD can be reduced as
much as 75% depending on the breakthrough volume used. Since this
266
-------
760
700
650
600
650
500
450
5 400
f
O 350
8 300
250
200
150
100
60
0
I
10
20
30
40
50 60
BED VOLUME
70
80
90
100
110
Figure 3. Chemical oxygen demand of various fractions of carbon
treated dinoseb-atrazine composite.
-------
TABLE 3. TOLUENE CONCENTRATIONS IN VARIOUS FRACTIONS
OF CARBARYL WASTEWATER
Sample Toluene Concentration
(mg/L)
Carbaryl waste undiluted 160
Biological treatment units (10% carbaryl
waste in municipal waste)
Influent after 24 hours 2.5
Effluent 0.001
Air stripping control units (10% carbaryl
waste in deionized water)
Influent after 24 hours 0.9
Effluent 0.1
268
-------
concentrated wastestream is a relatively small fraction of the total plant
effluent, it can then be combined with the dilute dinoseb-atrazine stream
and retreated with clean carbon. The organics that breakthrough this final
carbon can then be biologically treated.
OZONATION
A final example demonstrates the difference between treating a compound
in a pure solution and treating the same compound in a real-world wastestream.
Figure 4 presents data on the rate of ozonation of glyphosate in distilled
water. Ozone was supplied at a rate of 42 ing/minute. In the presence of an
excess concentration of ozone, destruction of glyphosate followed first-order
kinetics with respect to glyphosate concentration. The time constant for the
reaction, as computed from the slope of -0.0095, was 0.219 min'1. The half
life of glyphosate under these conditions was about 32 minutes.
By contrast the ozonation of glyphosate production wastewater after
initial biological treatment produced little reduction in glyphosate concen-
tration. The ozonation of a biologically treated effluent containing 92 mg/L
glyphosate and 400 mg/L COD was attempted. Two hours of ozonation at the
same rate as above reduced glyphosate concentration by only 12 mg/L.
SUMMARY
The increasingly strict standards governing the discharge of pesticide
production wastewaters may reduce the number of such wastestreams which are
currently discharged to POTW's. The BPT pesticide standard for those waste-
streams regulated is 0.0018 pounds of pesticide discharged after the final
treatment step for every 1000 pounds of pesticide produced. Achieving this
standard after municipal treatment would require extensive pretreatment of
most pesticide wastewater. Given the cost of pretreatment, many manufac-
turers may find it cheaper to design a complete treatment system including
a biological system tailored to their specific needs.
REFERENCES
Kelso, G. L., R. R. Wilkinson, J. R. Malone, Jr., and T. L. Ferguson.
Development of Information on Pesticides Manufacturing for Source
Assessment. EPA-600/2-78-100, Environmental Protection Agency,
Research Triangle Park, N. C., 1978.
Swisher, R. D. Surfactant Biodegradation. Marcel Dekker, Inc. N, Y., 1970.
Tomlinson, T. G., A. G. Boon, and C. N. Trotman. Inhibition of Nitrification
in the Activated Sludge Process of Sewage Disposal. Jour. Appl. Bact.
29(2) 266-291, 1966.
269
-------
TIME (min)
locj C
H
g
<
DC
Z
LU
O
2
O
o
o
o
60
TIME (min)
90
120
Figure 4. Rate of ozonation of glyphosate.
-------
BIBLIOGRAPHY
Little, L. W., R. Zweidinger, E. Monnig, and W. J. Firth. Treatment
Technology for Pesticide Manufacturing Effluents: Atrazine, Manet),
MSMA, Oryzalin. EPA-600/2-80-043, EPA, RTP, NC, 1980.
Monnig, E. C., R. Zweidinger. Treatment Technology for Pesticide Manufac-
turing Effluents: Carbaryl. Final Report for Contract 68-02-3688.
EPA, IERL, RTP, NC (in press).
Monnig, E. C., R. Zweidinger. Treatment Technology for Pesticide Manufac-
turing Effluents: Dinoseb and Atrazine. Final Report for Contract
68-02-3688, EPA, IERL, RTP, NC (in press).
Monnig, E. C., R. Zweidinger. Treatment Technology for Pesticide Manufac-
turing Effluents: Dazonet. Final Report for Contract 68-02-3688, EPA,
IERL, RTP, NC (impress).
Monnig, E. C., R. Zweidinger, M. Warner, R. Batten, D. Liverman. Treatment
Technology for Pesticide Manufacturing Effluents: Glyphosate. Final
Report for Contract 68-02-3688, EPA, IERL, RTP, NC (in press).
Zweidinger, R., T. Wolff, R. Hendren, R. Batten, M. Warner, D. Liverman,
L. Little. Treatment Technology for Pesticide Manufacturing Effluents:
Mancozeb. Final Report for Contract 68-02-3688, EPA, IERL, RTP, NC
(in press).
271
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PB83-U2331
LOS ANGELES COUNTY EXPERIENCE IN -THE CONTROL AND
TREATMENT OF INDUSTRIAL WASTEWATER DISCHARGES
By: L. S. Directo, Supervising Civil Engineer
C. W. Carry, Asst. Chief Engineer and Asst.
General Manager, and
J. F. Kremer, Head, Industrial Haste Section
County Sanitation Districts of Los Angeles County
1955 Workman Mill Road
Whittier, California 90607
ABSTRACT
The Sanitation Districts of Los Angeles County (LACSD) adopted, on
April 1, 1972, an ordinance regulating industrial wastewater discharges,
This ordinance established a number of industrial waste regulatory programs
which included industrial waste permits, an industrial surcharge program,
industrial plant inspections, and wastewater monitoring and enforcement
activities. The basic element of the industrial waste source control
program is the implementation of the Phase I industrial wastewater effluent
limits, which have been strictly enforced since July 1, 1977. The effluent
guidelines established discharge limits for cyanide, heavy metals and total
identifiable chlorinated hydrocarbons (T1CH), This paper will discuss the
impact of major industrial companies on the Districts' Joint Outfall System
(JOS) sewerage system and wastewater treatment facilities and the role of
the Districts in the implementation and enforcement of the Phase I limits.
The effectiveness of the source control program in the JOS will also be dis-
cussed by examining the influent pollutant mass flows to the Districts'
Joint Water Pollution Control Plant (JWPCP). For instance, examination of
the mass inflow data to JWPCP from January 1975 to December 1979 reveals
significant decreases in the levels of As, Cr, Cu, Cn, Pb, Zn and TICK, but
only minor decreases for such parameters, as Ag, Cd, Hg and Ni. It is
estimated that approximately 85% of the affected industrial companies are
now meeting the Districts' Phase I limits through good housekeeping
techniques.
INTRODUCTION
The Sanitation Districts of Los Angeles County (LACSD), which were
created in the 1920's under the authority granted by the California County
Sanitation Districts Act of 1923, provide sewerage facilities for treat-
ment and disposal of sanitary and industrial wastewaters generated from
areas largely within the Los Angeles County boundary. There are currently 27
272
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separate sanitation districts comprising the LACSD. Fifteen of these
districts have combined to form the Joint Outfall System (JOS), which pro-
vide a common sewerage system serving approximately 3.7 million people and
8000 industrial companies located in 74 cities encompassing about 750
square miles of Los Angeles County. The Sanitation Districts' JOS has
five inland treatment plants providing secondary and tertiary treatment
facilities with a combined capacity of about 80. mgd. The sixth and largest
treatment plant in the JOS, the Joint Water Pollution Control Plant (JWPCP),
provides advanced primary treatment and deep ocean disposal for 350 mgd of
wastewater. Figure 1 presents the service area of the JOS. The JWPCP is
currently being converted to partial secondary treatment with a scheduled
completion for 200 mgd capacity by 1982.
The main objective of this paper is to describe the LACSD experience
in the administration and implementation of a rigorous source control
program in an effort to control and/or minimize adverse effects of in-
dustrial wastewaters on the sewerage system and wastewater treatment
facilities.
ESTABLISHMENT OF AN INDUSTRIAL WASTE SOURCE CONTROL PROGRAM
Before 1972, the Sanitation Districts did not have a strong program of
controlling industrial wastewater discharges. Because of its organizational
structure, the Sanitation Districts do not control local sewers, hence had
no information on requests for industrial sewer connections. The industrial
waste source control program available at that time consisted of:
a) Districts' policy restricting discharges to the Districts' trunk
sewers. This policy required local cities to submit to the
Districts certain information on any proposed industrial sewer
connection.
b) Prohibitions of industrial wastewater discharges containing
cyanide, flammable materials, low pH or constituents which
would clog the sewers. Enforcement of these specific pro-
hibitions were accomplished either through the local cities
or through the powers granted to the Districts under state
laws.
These earlier source control programs, while adequate in the 1960's,
could not meet more stringent regulations established in 1972 by Federal
Public Law 92-500 and in the State of Califnornia Original Ocean Plan. Thus,
to meet both Federal and State water quality goals, the Sanitation Districts
adopted, on April 1, 1972, "An Ordinance Regulating Sewer Construction,
Sewer Use and Industrial Wastewater Discharges" (Ordinance). The Ordinance
has been established to adequately regulate industrial wastewater dis-
charges, to provide for equitable distribution of the Districts' costs
through a user charge (surcharge) program and to provide procedures for com-
plying with the requirements imposed upon the Districts by Federal and
State agencies.
273
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CITY OF
LOS ANGELES
SAN JOSE CREEK WRP
WHITTIER NARRO
WRP
SANITATION DISTRICTS
OF
LOS ANGELES COUNTY
ORANGE COUNTY
LOS COYOTES WRP
A
JOINT
WATER
POLLUTION
CONTROL
PLANT A
LONG BEACH WRP
MILES Q
7 SAN BERNADINO
. COUNTY
-J.W.RC.R
OCEAN OUTFALL
Figure I.
Joint outfall districts
-------
The Districts' Ordinance, which became effective on July 1, 1972, man-
dated the establishment of an industrial wastewater discharge permit program
to identify and regulate industrial dischargers. As part of the permit
program, all existing and new industrial companies are required, as a pre-
requisite to obtaining an industrial wastewater discharge permit, to submit
information indicating the volume, composition and concentration of the
wastewater discharge and describing the industrial process and wastewater
pretreatment facility. The permit program, which requires certain industrial
dischargers to submit periodic self-monitoring reports on specified waste-
water parameters, provides the basic information used in establishing
numerical effluent limits for source control of toxic wastewater constituents,
No major source control efforts were, however, made until after July 1, 1975.
ADMINISTRATION OF THE INDUSTRIAL WASTE PROGRAM
Personnel Requirements
Figure 2 presents the organizational structure of the Industrial Waste
Section. This section is charged with the responsibility of implementing
the Districts' industrial waste regulatory program. There are currently 48
positions filled out of the 66 persons authorized for the Section. Among
the 48 positions, 16 are graduate engineers (4 Ph.D., 7 M. S. and 5 B. S.
degree graduates), 14 industrial waste inspectors, 6 monitoring crew persons,
5 surcharge auditors, 2 drafting technicians and 5 clerical support people.
The Section is composed of 4 subsections which are under the direct super-
vision of the Section Head. The main functions of these subsections are
described below.
Permit Processing Subsection
In accordance with Section 401 of the Districts' Ordinance, all com-
panies discharging industrial waste directly or indirectly to the Districts'
sewerage system are required to apply for an industrial wastewater discharge
permit for each sewer connection. All new industrial companies must obtain
a permit before their wastewater can be accepted in the Districts' sewerage
and treatment facilities. Under this permit program, industrial dischargers
are required to (a) submit detailed information on their wastewater generat-
ing operation, (b) install necessary pretreatment facilities to meet
Districts' requirements, and (c) periodically report wastewater flow and
wastewater characterization test data.
The main function of this subsection is to implement the Districts'
industrial wastewater discharge permit program. All permit applications
submitted by industrial companies are reviewed by the plan evaluation
engineers or the drafting technicians to insure that adequate information
on the process generating the wastewater is provided and that complete
information on spill containment, flow monitoring and pretreatment
facilities is provided. Review of permit applications from existing in-
dustrial companies locates and identifies industrial wastewater problems
which can be corrected through permit requirements. Permit requirements
placed on new construction submittals prevent potential problems from
occurring.
275
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VISOR,
ROCESSIN8
liing
jlneer
(1)
ALUATION
IEER
glneer
••ring
clot*
,111 (5)
FECMNICIAN
ch. 1 1 1
>ch. li
•ch.l
(2)
LERICAL
•ORT
t CUrK
(1)
-
DRAFTING TE
Drafting T*
Drafting T*
Drafting T*
CHNICIAN INDUS
SE(
:h . Ill
:h. 1
(0) 1
TRIA
:TIOK
n En
HEAD INSPECTOR
Supervising
Industrial Waete
Inspector
1 (1)
LEAD INDUSTRIAL
WASTE INSPECTOR
Senior Industrial
Waete Inspector
4 (3)
INDUSTRIAL WASTE
INSPECTORS
Industrial Wast*
Inspector II
Industrial Wast*
|2.n.p.ctor 1 (9)
SUPERVISOR,
FIELD ENQR.
Supervising
Civil Engineer
1 (1)
PROJECT ENGINEER
Civil Engineer
Engineering
Associate
2 I.H.IU (1)
ENFORCEMENT
OFFICER
Senior Industrial
Watte Inspector
1 ( 1)
L WASTE SECRETARY
HEAD
Secretary 1 1
(1) 1
(1)
1
SECR-CLER
SUPPORT
Senior Typist
Clerk
1 (1)
SUPERVISOR ,
INDUSTRIAL WASTE
ENGINEERING
Supervising
Civil Engineer
1 (1)
SUPERVISOR
MONITORING CREW
Supervising
Engr.Tech.
1 (1)
LEAD MONITORING
CREW WORKER
Senior Engineering
Tech.
1 (1)
MONITORING CREW
WORKER
Engr. Tech.
T (3)
PROJECT ENGINEER
Civil Engineer
Engineering
Associate
8 1,11,111 (9)
SUPERVISOR .
SURCHARGE
PROCESSING
I.W. Surcharge
Supervisor
1 (1)
SENIOR SURCHARGE
ASSISTANT
I.W. Surcharge
Assistant II
2 (1)
LEAD CLERICAL
SUPPORT
Sr. Typist Clerk
1 (1)
CLERICAL SUPPORT
Typist Clerk 1
Typist Clerk II
1 (0)
SURCHARGE
ASSISTANT
, I.W. Surcharge
Assistant 1
4 (3)
—
CLERICAL SUPPORT
Typist Clerk II
Typist Clerk I
(I)
Figure 2. Industrial waste section table of organization,1979-80
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Inspection and Monitoring Subsection
This subsection is responsible for carrying out the industrial waste-
water source inspection and monitoring programs, to insure that the
Districts' regulatory program is properly observed and that adequate control
measures are practiced by industrial dischargers. This subsection also
carries out treatment plant upset investigations, and where appropriate, will
carry out enforcement actions against industrial wastewater dischargers who
are in non-compliance with the Districts' Ordinance requirements. The in-
spection function is carried out by 12 inspectors operating .in 3 teams under
the supervision of one supervising inspector.
The industrial waste monitoring program, which is carried out by 5
monitoring crew members plus one supervisor, has been implemented to verify
the flow rate and wastewater characterization test results reported via the
industrial self-monitoring program. Approximately 350 major industrial
wastewater dischargers (companies with wastewater flows equal to or greater
than 50,000 gpd) are being monitored about twice a year. An additional 120
industrial wastewater dischargers are also being monitored about twice a
year as part of the Phase I source control program. For the 1979 calendar
year, about 2100 24-hour composite samples and/or flow measurements were made.
Industrial Wastewater Engineering Subsection
This subsection, which is made up of 6 project engineers C3 with PhD,
and 3 with M.S. degrees) under one supervising civil engineer, provides tech-
nical support and expertise in specific industrial waste fields. The princi-
pal functions of the project engineers in this subsection are (a) to evaluate
the activities of industrial companies with respect to wastewater quality and
quantity, (b) to resolve technical and economic problems arising from indus-
trial use of the Districts' sewerage system, (c) to provide a consulting ser-
vice to the plan evaluation engineers in the permit subsection; reviewing
major and critical permit applications, recommending appropriate permit con-
ditions and developing technical and policy standards for use by the plan
evaluation engineers, and (d) to assist personnel of the surcharge subsection
in the development of technical information and guidelines needed in auditing
industrial surcharge statement submittals.
The following are the major industrial waste fields with an assigned
industrial waste project engineer:
(a) Petroleum Product and Refining
(b) Metal Finishing
(c) Chemical Process
(d) Food and Beverage Processing
(e) Paper and Textile Manufacturing
(f) Basic Metals
Surcharge Processing Subsection
This subsection has the responsibility of administering the Districts'
industrial wastewater treatment surcharge program, in effect since July 1,
277
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1972, for the following purposes:
(a) To insure that industrial dischargers using the Districts'
sewerage system pay an equitable share of the treatment costs,
(b) To comply with revenue programs promulgated by State and
Federal agencies, and
(c) To provide economic incentives to the industrial companies
to control pollutants at the source.
In the seven years since the surcharge program has been in effect, the
Districts have collected a total of 36.58 million dollars from industrial
companies. For the fiscal year 1978-1979, a total of 7.3 million dollars
net surcharge was collected from 1,151 companies.
Cost of Administering 'the Industrial Waste Program
The total expenses from the administration and implementation of the
Districts' industrial wastewater source control program were $1.27 million
during the 1978-1979 fiscal year. It is anticipated that the cost of
administering the industrial waste regulatory program may increase in sub-
sequent years because of increased levels of regulatory activities required
to implement more stringent Federal pretreatment regulations.
IMPLEMENTATION OF THE INDUSTRIAL WASTEWATER SOURCE CONTROL PROGRAM
In 1975, the Sanitation Districts established a source control program
geared to meet the following major objectives:
(a) To allow the JWPCP and the five other inland water reclamation
plants within the JOS to comply with the effluent discharge
limitations established by the 1972 California Ocean Plan.
(b) To protect the public, the environment and Districts' personnel
and facilities from potentially harmful industrial wastewater
discharges.
(c) To maintain a reasonable cost-benefit ratio for Districts'
services to the public.
The basis for implementing the districts' source control program is the
Phase I limits, shown in Table I. These limits were adopted for the JOS by
the Sanitation Districts' Board of Directors on July 1, 1975. The limits
shown in Table 1 were developed in cooperation with the Metal Finishing Asso-
ciation of Southern California, the City of Los Angeles, and the Sanitation
Districts of Orange County. It should be pointed out that the Phase I limits
were developed to comply with the orginal California Ocean Plan effluent
limits, presented in Table 2, which were established on July 6, 1972.
As the first step in the implementation of the Districts' source
control program, copies of Phase I limits along with detailed definitions
278
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TABLE 1. INDUSTRIAL MASTEWATER EFFLUENT LIMITATIONS*
Constituent
Arsenic
Cadmium
Chromium (Total)
Copper+
Lead
Mercury
Nickel
Silver
Zinc
Cyanide (Total)
Total Identifiable
Chlorinated
Hydrocarbons
Industrial Wastewater Effluent Limitations
Phase I Control Period
(mg/1)
3
15
10
15
40
2
12
5
25
10
Essentially None
* Adopted on July 1, 1975 for Joint Outfall Districts.
+ Based on toxicity criteria rather than the Ocean Plan Limits.
279
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TABLE 2. CALIFORNIA OCEAN PLAN EFFLUENT LIMITATIONS*
Constituent
Effluent Limitations
(mg/1)
Arsenic
Cadmium
Total Chromium
Copper-
Lead
Mercury
Nickel
Silver
Zinc
Cyanide
Phenolic Compounds
Total Chlorine Residual
Ammonia
Grease and Oil (hexane
extractables)
Total Identifiable
Chlorinated Hydrocarbons
0.01
0.02
0.005
0.2
0.1
0.001
0.1
0.02
0.3
0.1
0.5
1.0
40.
10.
0.002
* Water Quality Control Plan for Ocean Waters of
California, established July, 1972.
280
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and guidelines for meeting the requirements, were mailed to about 700
affected companies, mainly metal finishing companies, in October 1975. In
these mass mailings, the Districts established an 18-month compliance period
to provide companies ample opportunity to institute a Phase I source control
program capable of meeting the effluent limits. An additional 6-month ex-
tension was added by the Districts to the original compliance date. Thus,
it was not until July 1, 1977 when the Phase I limits began to be rigorously
enforced.
During the 24-month interim period prior to the enforcement of the
Phase I limits, the Sanitation Districts embarked on a comprehensive
program designed to identify industrial companies which would require con-
trols on their wastewater discharges. The program was carried out through
the following steps:
(a) A list of industrial companies, especially those with Standard
Classification, (SIC) 3471 and 3479 for metal finishers, were
compiled from the Districts' industrial wastewater discharge
permit files and updated using information from telephone
directories, manufacturers' registers and field inspection
reports.
(b) The Districts' monitoring of industrial sources was established
and a follow-up procedure was also initiated to improve industrial
companies self-monitoring report submittals.
(c) All companies found in violation of the phase limits were notified
by letter and required to submit information on a plan of action
necessary to comply with established limits. The affected com-
panies were also visited by Districts' inspectors to facilitate
correction of existing problems.
Since July 1, 1977, industrial dischargers that show Phase I violations
in their self-monitoring report submittals are sampled by the Districts'
monitoring crews to confirm the indicated violation. Enforcement notices
are issued to all industrial dischargers who are not in compliance as in-
dicated in the test results of Districts' sampling.
ENFORCEMENT PROGRAM
While in general the majority of industrial dischargers have been in
compliance with the Districts' Ordinance requirements, in a number of cases
it has become necessary to initiate enforcement actions against recalcitrant
companies. Enforcement actions are indicated in any one or more of the
following:
(a) industrial discharges which cause treatment plant upsets
(b) delinquent surcharge problems
(c) violations of wastewater ordinance requirements
The present enforcement procedure is to issue non-compliance notices
to companies, whenever a violation has been detected as a result of
281
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Districts' inspection, sampling or testing. Three levels of notices are
used in the enforcement process, issued in the following order:
(a) Information Notice
(b) Violation Notice
(c) Final Notice of Violation
After each notice is issued, the company is given a reasonable period
of time, usually 30 days, to correct the non-compliance status. Failure to
comply through these 3-step enforcement procedures may result in referring
the matter to the District Attorney (D.A.) of Los Angeles County for con-
sideration of criminal prosecution. To date, there have been only 12 cases
that have gone beyond the third step of enforcement and only two cases were
not resolved immediately soon after the D. A, conference. In both these
cases, however, the offending company was found guilty in the court of law
and compliance was quickly obtained. It should be emphasized that the
Districts' policy in dealing with companies has been to foster cooperation
and to give the non-complying company ample opportunity to correct the
violation.
Table 3 presents a summary of the type and number of enforcement
actions against industrial dischargers during 1979. The summary data in-
dicate that the major percentage of enforcement activity was for Phase I
limit violations. The enforcement activity from 1975 through December 1979
is presented in Figure 3. It is apparent from the figure that enforcement
activities have increased appreciably after July 1, 1977 when Phase I limit
enforcement was started. The greater number of enforcement actions in 1979
was brought about by a vigorous campaign to have companies comply with
permit requirements to install flow monitoring, spill containment and rain-
water diversion systems in addition to the installation of necessary pre-
treatment systems to comply with Phase I limits,
RESULTS OF THE DISTRICTS' SOURCE CONTROL PROGRAM
As discussed previously, the JOS serves a large portion of Los Angeles
County and consists of the JWPCP and five inland water reclamation plants
(WRP). These reclamation plants are operated so that all skimmings and
sludges generated are discharged to an outfall sewer and eventually flow to
the JWPCP. Since heavy metals and other pollutants removed from the five
WRP are concentrated in the generated sludges which discharge to the JWPCP,
the raw sewage data at the JWPCP are good indicators of the total mass
pollutant flows in the JOS. Thus, the results of the Districts' source
control program can best be presented by examining the long term trends of
mass constituents in the flow to the JWPCP as shown in Figures 4 through
14. The results presented in these figures are 12-month running averages of
the specific constituent. In each of these figures, the lower dotted band
represents the estimated residential contribution; the solid line represents
the original Ocean Plan discharge limits (the basis for the establishment of
the Phase I limits); and the band of horizontal lines represents the
estimated pollutant mass flow to the JWPCP when all companies are in full
compliance with the Phase I limits.
282
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TABLE 3. SUMMARY OF INDUSTRIAL WASTE ENFORCEMENT FOR 1979
Month
Jan.
Feb.
Mar.
Apr.
May
June
July
Aug.
Sept.
Oct.
Nov.
Dec.
No. of
Companies
Under
Enforcement
57
58
67
74
78
87
96
104
93
89
94
94
Total No. of
Enforcement
Actions
60
62
75
83
92
96
113
104
97
94
103
104
Type of Enforcement Action
Phase I
No.
36
37
44
49
49
50
42
33
34
28
27
27
% of
Total
60.1
59.7
58.7
59.0
53.3
52.1
37.1
31.7
35.0
29.8
26.2
26.0
No Permit
No.
1
1
3
4
6
8
14
30
28
20
17
13
i
% of
Total
1.7
1.6
4.0
4.8
6.5
8.3
12.3
28.8
28.8
21.2
16.5
12.5
Flowmeter
No.
11
9
7
9
11
10
13
19
14
21
20
?3
% of
Total
18.3
14.5
9.3
10.8
12.0
10.4
11.5
18.2
14.4
22.3
19.4
22.1
Low pH
No.
4
5
10
11
11
10
14
12
5
6
8
6
% of
Total
6.7
8.1
13.3
13.3
12.0
10.4
12.4
11.5
5.1
6.4
7.7
5.8
Surcharge
No.
0
3
3
0
5
6
7
1
5
8
9
10
% of
Total
0
4.8
4.0
0
5.4
6.3
6.1
0
5.1
8.5
8.7
9.6
Other
No.
8
7
8
10
12
12
23
9
11
11
22
25
% of
Total
13.3
11.3
10.7
12.0
10.9
12.5
20.4
8.6
11.3
11.7
21.3
24
-------
150
140-
130-
120-
Q
LL!
D I 10
CO
cr
o_ 100
o
z
Id 90
m
oo
Z 80
o
-------
In examining the plots of the various constituents, it should be
pointed out that prior to July 1975, when the Phase I limits were adopted,
essentially no significant efforts were made by industrial companies to
curtail toxic waste discharges. Therefore, the data points obtained in
1975 would provide a good estimate of the pre-source control baseline data.
Arsenic
Figure 4 presents the mass flow of arsenic. As indicated in the figure,
the Districts have consistently met the Ocean Plan discharge limits since
July 1975. While the source control program probably had a definite impact
in the reduction of arsenic mass flow, it is believed that the following
factors may also have contributed to the drop in arsenic: a) changes in
the formulation of consumer products and b) improved laboratory analytical
techniques. The current indicated average of 35 to 40 Ibs/day is within
the range expected if all companies are in full compliance with the Phase I
limit of 3 mg/1.
Cyanide
The cyanide mass flow level in the JOS, presented in Figure 5 has con-
sistently met the Ocean Plan discharge limit, even before the adoption of
the source control program. Through vigorous efforts in implementing the
source control program, many industrial companies have installed cyanide
pretreatment equipment resulting in a 55% decrease in the cyanide mass flow
at the JWPCP, to a current level of 540 Ibs/day. This level of cyanide has
been observed in the past two years, indicative of essentially full com-
pliance of companies with the Phase I cyanide level of 10 mg/1.
As an accommodation to industrial companies, the Districts have been
operating a cyanide disposal station at JWPCP. The toxic waste received
at this station are bled at a controlled rate into a trunk sewer just
upstream of JWPCP. Approximately 400 Ibs/day of cyanide are currently
being discharged at this station. This facility, however, will soon be
closed because the EPA and the State of California regulations require com-
pliance with certain pretreatment requirements for a hazardous disposal
facility such as this. With an eventual closure of this facility, an
additional cyanide reduction can be achieved for an overall removal of
approximately 90% from the pre-source control baseline level.
Cadmium
As indicated in Figure 6, the cadmium levels through 1979 have been
appreciably below the Ocean Plan discharge limits. From 1975 to date, the
mass flow of about 85 to 100 Ibs/day in the JWPCP influent is within the
value expected with all companies in full compliance with the Phase I limit
of 15 mg/1. The cyanide disposal station at JWPCP contributes approximately
10 Ibs/day of cadmium; therefore, an additional reduction in cadmium is
anticipated after the closure of the cyanide station.
285
-------
o
-o
>v
(A
.O
_J
O
Z
LU
(/)
o:
ISO
135
120
105
90
75
60
45
30
o '"*; ; '• i" i1
BASED ON OCEAN PLAN LIMIT
BASED ON FULL PHASE I COMPLIANCE
RESIDENTIAL CONTRIBUTION
JAJOJlAJOJAJOJAJOJAJOJAJO
1975 1976 1977 1978
YEAR
1979
1980
Figure 4. Mass inflow of Arsenic at the J.W.RCP
286
-------
2000
BASED ON OCEAN PLAN LIMIT
BASED ON FULL PHASE I COMPLIANCE
RESIDENTIAL CONTRIBUTION
WITH CN STATION CLOSED
JAJOJAJOJAJO JAJOJAJOJAJOJ
1975 1976 1977 1978 1979 1980
YEAR
Figure 5. Mass inflow of Cyanide at the J.W.RC.R
287
-------
"ZOO
225-
200
175
« 150
&
_J
125
50-
25-
BASED ON OCEAN PLAN LIMIT
BASED ON FULL PHASE I COMPLIANCE
RESIDENTIAL CONTRIBUTION
O-IT-I—i— "i"""* <—•—r-1—»—'—i—' ' i —•—«—i » '""'
JAJOJAJOJAJOJAJOJAJOJAJOJ
1975 1976 1977 1978 1979 1980
YEAR
Figure 6. Mass inflow of Cadmium at the J.W.P.C.P.
288
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Chromium
As shown in Figure 7, there has been a dramatic decrease in the
chromium levels at the JWPCP, starting about July 1976. This decrease of
about 50% in the mass flow of chromium has been achieved as a result of
vigorous enforcement of the Phase I limits. At the present time one large
leather tanning company and a number of small plating companies are period-
ically in violation of the Phase I limits of 10,mg/l. It is evident from
the figure, that even with full compliance by all companies with the Phase I
limits the original Ocean Plan limit can never be met. With the current
level of chromium at JWPCP, the districts should have no difficulty in meet-
ing the 1978 revised Ocean Plan limit of 2,000 Ibs/day.
Copper
The mass flow of copper presented in Figure 8 indicates a marked de-
crease of approximately 40% from the pre-source control level. The dash line
at 1000 Ibs/day copper is established on the basis of toxicity of copper to
the activated sludge process and is more restrictive than the influent limit
required by the Ocean Plan effluent limit. The Phase I source control
program has been instrumental in this reduction in copper inflow. Although
the copper concentration has consistently met the original Ocean Plan limit,
it still is not within the range anticipated if all companies were to fully
comply with the Phase I limits of 15 mg/1 copper. An additional 80 Ibs/day
of copper is expected to be removed with the closure of the cyanide disposal
station.
Lead
The decrease in the lead concentration in the JWPCP influent over the
years is illustrated in Figure 9. As indicated in the figure, even before
January 1975, the mass flow of lead has been continuously meeting the Ocean
Plan limit. The source control program is believed responsible for approx-
imately 20% of the lead removal at the JWPCP. Approximately an additional
10% should be removed with full compliance of industrial dischargers with
the Phase I limit of 40 mg/1 of lead.
Mercury
Ad indicated in Figure 10, there has been essentially no beneficial
effect of the Phase I program on the control of mercury. It appears that
mercury originates primarily from domestic sources, thus any control imposed
on industrial dischargers will have virtually no effect on the mass inflow
to JWPCP. The levels of mercury in the influent to JWPCP are within the
range of concentration reported in EPA documents for structly sanitary
wastewater.
Nickel
Figure 11 presents the mass inflow of nickel to the JWPCP- As indica-
ted in this figure, the Phase I program has not had major success in reduc-
ing the level of nickel. Thus far, the nickel level has been above the
289
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3000
2700-
2400
o
-a
^1800-
-P
_J
"""1500
5
51200
O
o
900-
600
300
BASED ON OCEAN PLAN LIMIT
BASED ON FULL PHASE I COMPLIANCE
RESIDENTIAL CONTRIBUTION
J A J OJAJOJAJOJAJO JAJOJAJO J
1975 1976 1977 1978 1979 1980
YEAR
Figure 7.
Mass inflow of Chromium at the J.W.P.C.P
290
-------
25OO
BASED ON OCEAN PLAN LIMIT
BASED ON FULL PHASE I COMPLIANCE
RESIDENTIAL CONTRIBUTION
BASED ON COPPER TOXICITY TO
ACTIVATED SLUDGE PROCESS
—' innn . •»
JAJOJAJOJAJOJAJOJAJOJAJOJ
1975
1980
Figure 8. Mass inflow of Copper at the J.W.R C.P
791
-------
1500
1350-
1200
1050
< 750
-Q
-J 600
Q
2450
300-
150
BASED ON OCEAN PLAN LIMIT """^
BASED ON FULL PHASE I COMPLIANCE ==
RESIDENTIAL CONTRIBUTION 1KH
JAJOJAJOJAJOJAJOJAJOJAJOJ
1975 1976 1977 1978 1979 1980
YEAR
Figure 9. Mass inflow of LeadI alJhe J.W.P.CJ3.
292
-------
18-
16
14
»
12
BASED ON OCEAN PLAN LIMIT
BASED ON FULL PHASE I COMPLIANCE
RESIDENTIAL CONTRIBUTION
Z)
o
-------
1500
1350
1200
1050
7^900
o
jQ
_l
— 600
LLJ
O
z
450
300
ISO
0-4
BA3ED-ON OCEAN PLAN LIMIT
BASED ON FULL PHASE I COMPLIANCE
RESIDENTIAL CONTRIBUTION
JAJOJAJOJAJOJAJOJAJOJAJO J
1975 1976 1977 1978 1979 1980
YEAR
figure II. Mass inflow of Nickel at J.W.RC.R
294
-------
limit established by the original Ocean Plan. Approximately a 20% reduction
has been achieved to date. It is anticipated, however, that a 50% decrease
in nickel level could be achieved if all the affected industries were in
compliance with the Phase I limits of 12 mg/1 of nickel. More vigorous
efforts will be given to the control of nickel problems in 1980. It should
be emphasized, however, that with the current levels of nickel, the Dis-
tricts are still able to comply with the 1978 revised Ocean Plan limit of
7,900 Ibs/day. When the cyanide disposal station is closed, it is estimated
that a reduction of nickel discharged of about 125 Ibs/day will be obtained.
Zinc
A reduction of about 43% in the zinc level, shown in Figure 12, has
been achieved to date through vigorous enforcement of the source control
program. It is anticipated that an additional 10 to 15% removal will be
attained if all companies are in full compliance with the Phase I limit of
25 mg/1 of zinc.
Silver
Except for the increase in silver in the latter part of 1978, the mass
flow of this constituent has been within the range of values expected for
full, compliance with the Phase I limit of 5 mg/1 of silver. The period of
high silver mass flow observed in 1978, which is indicated in Figure 13, was
caused by one large company discharging wastewater containing silver greatly
in excess of the Phase I limits. This-particular discharger received a
large government contract to develop photographs and performed the work
without recovering large amounts of waste silver in the photo processing
wastes. The company made the necessary corrective action after being noti-
fied by the Districts of noncompliance.
TICK
The total identifiable chlorinated hydrocarbons (TITCH) in the JOS are
made up primarily of dichlorodiphenyltrichloroethane (DDT) and other pest-
icides and polychlorinated biphenyls (PCS). Figure 14 presents the mass
discharge of TICK. This figure illustrates the dramatic decrease in the
TICK discharge starting early in 1975. While the Districts' pressure on
industries to control these constituents definitely has significant impact
on the reduction of TICK, other factors that occurred prior to 1975 also
contributed to this situation. For instance, after June 1971, through
Districts' regulatory actions, a major DDT manufacturer ceased discharge of
DDT to the JOS. Considerable amounts of DDT-laden sediments, however,
remained in the sewers downstream of this company. In 1971 and 1972,
several cleaning operations were undertaken which removed a major portion
of the DDT-laden sediments. These cleaning operations while successful,
were abandoned because it caused resuspension of fine sediments which
flowed to the JWPCP and eventually discharged to the ocean.
The other major component of TICK is PCB's which are used in electrical
devices, cooling devices and in microcoating of carbonless copying paper.
The Districts have a continuing program to control PCS discharges, primarily
295
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7500
6750 ^
6000
5250
4500
o
>
_J
~ 3000
O
Z
2250
1500
750-
BASED ON OCEAN PLAN LIMTT
BASED ON FULL PHASE I COMPLIANCE
RESIDENTIAL CONTRIBUTION
JAJOJAJO JAJOJAJOJAJO J A J 0
1975 1976 1977 1978 1979 1980
YEAR
Figure 12. Mass inflow of Zinc at the J.W.P.C.P.
296
-------
250
225-
200-
175-
o
TJ
«' 125-
100
tr
LJ
>
_J
en
50
25-
BASED ON OCEAN PLAN LIMIT
BASED ON FULL PHASE I COMPLIANCE
RESIDENTIAL CONTRIBUTION
JAJOJAJOJAJOJAJOJAJOJAJOJ
1975 1976 1977 1978 1979 I960
YEAR
Figure 13. Mass inflow of Silver at the J.W R C.P.
297
-------
BASED ON OCEAN PLAN LIMIT
BASED ON FULL PHASE I COMPLIANCE
RESIDENTIAL CONTRIBUTION
JAJOJAJOJAJOJAJO JAJOJAJOJ
1975 1976 1977 1978 1979 1980
YEAR
Figure 14. Mass inflow of T.I.C.H. at the J.W.P.C.P.
298
-------
from paper companies which used recycled carbonless paper and from electri-
cal companies or companies which manufacture or repair electrical transform-
ers or condensers which contain PCB's. The successful control of PCB is
evidenced by the reduction in the mass loading from 60.1 Ibs/day in 1972 to
4.9 Ibs/day in 1978. The current relatively stable level of TICK at the
JWPCP is considered within the anticipated range with essentially full com-
pliance by contributing industries.
SUMMARY
To meet the water quality goals established in 1972 through the Federal
Public Law 92-500 and the California Ocean Plan (Original), the LACSD Board
of Directors adopted, on April 1, 1972, an ordinance regulating industrial
wastewater discharges. This Ordinance established a number of industrial
waste regulatory programs which include industrial waste permits, an
industrial surcharge program, plant inspections, and wastewater monitoring
and enforcement activities.
A major element of the industrial waste source control program is the
implementation of the Phase I limits, adopted by the JOS districts on July 1,
1975 and strictly enforced since July 1, 1977. The Phase I program estab-
lished industrial effluent discharge limits for cyanide, heavy metals and
TICK.
The LACSD have successfully implemented the industrial waste source
control program as indicated by the significant decrease in the mass inflow
to JWPCP of As, Cr, Cu, Cn, Pb, Zn, and TICK. Other parameters, such as Ag,
Cd, and HG, while consistently meeting the Phase I limits, have not changed
significantly from 1975 through 1979. On the other hand, the Ni level has
remained above the established Ocean Plan effluent limit, but should be
reduced with the closure of the cyanide disposal station at JWPCP.
As of December 1979, it is estimated that about 85% of the affected
industrial dischargers are meeting the Phase I limits through good house-
keeping techniques. The remaining companies, however, particularly those
metal platers using automatic plating equipment with high production rates,
as well as those using barrel plating or processing hard to drain parts,
have had to install end-of-the line treatment systems to meet the Phase I
effluent limits.
The administration and implementation of the Districts' industrial
waste source control program have been carried out by the Industrial Waste
Section, which currently has 48 personnel, at a total cost of $1.27 million
during the 1978-1979 fiscal year.
299
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PB83-1U2349
COMBINED MUNICIPAL-INDUSTRIAL WASTEWATER TREATMENT IN GARLAND, TEXAS
A. Netzer^1 , J. McNutt^1-* and W. B. Dollar^
(1) Environmental Sciences
The University of Texas at Dallas
Richardson, Texas
(2) Public Works
City of Garland
Garland, Texas
ABSTRACT
The Duck Creek Wastewater Treatment Plant is a combined municipal-indus-
trial treatment facility serving the City of Garland, Texas and portions of
the cities of Sachse, Mesquite, Sunnyvale, and Dallas, Texas. The municipal
effluents are from a population of over 150,000 and the industrial discharges
are from over 400 various light industries, ranging from paint manufacturing
and metal plating to food and dairy processing. Due to growth of both popula-
tion and industry serviced by this combined municipal-industrial wastewater
system, the Duck Greek Wastewater Treatment Plant was recently upgraded from
its original 10 MGD biological treatment facility to a 30 MGD facility by the
addition of a 22.5 MGD physical-chemical treatment process. Pretreatment
consists of trash screening, a 60 MG equalization basin with brush aerators,
bar screening, and grit removal. The biological treatment process consists
of primary clarification, primary trickling filters, intermediate clarifica-
tion, secondary trickling filters, and final clarification. The physical-
chemical treatment process consists of coagulation-flocculation with lime,
ferric chloride, and polyelectrolytes, clarification recarbonation, and ultra-
high rate sand filtration. Final treatment for both systems consists of
granular activated carbon adsorption and chlorine disinfection.
INTRODUCTION
The City of Garland, Texas is an industrial, suburban community of over
150,000 located on the northeast perimeter of Dallas, Texas in Dallas County.
The industrial community located in Garland, Texas is composed of over 400
various light industries. These industries, some with very little, but most
with no pretreatment, discharge their effluents into the municipal system.
The influent wastewater treatment at the Duck Creek Wastewater Treatment
Plant is composed of approximately 60-70% municipal and 30-40% industrial
wastes.
300
-------
Faced with an expansion of the existing wastewater treatment facility
at the Duck Creek Wastewater Treatment Plant from its previous 10 MGD bio-
logical configuration, the City of Garland elected to expand the facility
with the addition of 22.5 MGD physical chemical treatment process.
The pretreatment processes include trash removal with trash screens,
retention in a 60 MG equalization basin with brush aerators, bar screening
and grit removal.
The biological treatment configuration consists of primary clarifica-
tion, primary trickling filters, intermediate clarification, secondary trick-
ling filters, and final clarification.
The physical-chemical treatment process consists of coagulation-floccu-
lation, clarification, recarbonation, and ultra-high rate sand filtration.
Final treatment for both systems is accomplished with the use of granu-
lar activated" carbon adsorption and chlorination. Figure 1 shows the sche-
matic diagram of the Duck Creek Wastewater Treatment Plant.
INFLUENT AND EFFLUENT CHARACTERISTICS
Preliminary influent quality studies were conducted by the design engi-
neers at an independent laboratory (1)- Data was averaged and described
below in Table 1. The design of the plant expansion (the physical-chemical
treatment plant) was based on these results.
TABLE 1 AVERAGE INFLUENT WASTEWATER CHARACTERISTICS
Parameter Averaged Result
Total BOD5 (mg/1) 266
Total COD (mg/1) 542
Suspended Solids (mg/1) 233
Alkalinity (mg/1 as CaC03) 200
pH (Mean) 7.35
Recent studies by the City of Garland laboratory at the Duck Creek
Wastewater Treatment Plant have the following influent characteristics for
1979 (Table 2).
301
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TABLE 2 AVERAGE INFLUENT WASTEWATER CHARACTERISTICS, 1979
Parameter Averaged Result
Total BOD5 (mg/1) 239
Total COD (mg/1) .. , 540
Suspended Solids (mg/1) 233
pH (Mean) 7.10
Comparing the 1971 design-based data and the 1979 actual operational
data shows the consistency of the influent to the facility.
The State of Texas permit which allows for discharge from this treat-
ment facility has the following criteria:
Quality:
BOD,- 10 mg/1, monthly average, 24 hours daily
composite, and individual samples
Total SS 10 mg/1, monthly average, 24 hours daily
composite, and individual samples
Chlorine residual 1 mg/1, after 20 minutes contact time
Volume:
Average Design Flow 30 MGD
Actual Flow Records (1979): Maximum: 30 MGD
Minimum: 9.5 MGD
Average: 18.3 MGD
The discharge permit for the previous biological treatment facility was
for a maximum flow rate of 10 MGD, with a BOD5 not to exceed 20 mg/1 and a
SS not to exceed 20 mg/1. The upgrading of the Duck Creek Wastewater Treat-
ment Plant to a combined, split-stream biological and physical-chemical
treatment process resulted in a more stringent discharge permit from the
State of Texas.
PRETREATMENT
The influent wastewater arrives at the Duck Creek Wastewater Treatment
Plant via a 48" pipeline. Immediately after entry, it is passed through a
5-foot wide Jeffery Manufacturing Company mechanically cleaned trash screen.
Objects removed are collected and hauled to the City of Garland landfill.
The average trash removed is approximately 1000 Ibs./day.
302
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TRASH II
SCREEN! I
EQUALIZATION/"
BASIN I
METERING
VAULT
BAR
SCREENS
GRIT
BASINS
OJ
o
CO
RECARBONATION
BASINS
ULTRA-HIGH
RATE
FILTERS
PRIMARY
TRICKLING
FILTER
INTERMEDIATE
CLARIFIER
PRIMARY
TRICKLING
FILTER
SECONDARY
TRICKLING
FILTER
FINAL
CLARIFIER
CARBON ADSORPTION
FACILITY
CARBON
REGENERATION
FURNACE
SECONDARY
TRICKLING
FILTER
FINAL
CLARIFIER
Figure I. DUCK CREEK WASTEWATER TREATMENT PLANT
SUNNYVALE.TEXAS
-------
The influent wastewater flows by gravity to a 60 MG equalization basin.
The equalization basin was constructed in order to provide a uniform dis-
charge to the treatment processes, regardless of changes in flow rate and to
eliminate shock loads. The basin is oval in shape, divided down the center
to provide a single pathway. The basin is 1,112 feet long, 132 feet wide,
and 12 feet deep. The equalization basin is equipped with four Arvo Model
25 E flow developers to insure good mixing to eliminate solids precipitation
in the basin.
The basin is also equipped with four Passavant 20-foot long Lagoon-
Master Floating Mammoth Brush Rotators. These brush aerators introduce oxy-
gen into the wastewater in the basin to avoid septic conditions during the
8-hour residence time.
The wastewater flows by gravity through a meter vault for measurement,
through one of two 36-inch parallel Jeffery Manufacturing Company mechani-
cally cleaned, bar screens. A third bar screen, a Jeffery Manufacturing 48-
inch, hand-cleaned bar screen is available in case of mechanical failure.
The bar screenings are collected and disposed of with the collected grit in
the City of Garland landfill.
Immediately following bar screening, the wastewater is passed into one
of two aerated grit removal basins. These basins are circular, 34 feet in
diameter and 25 feet in depth. Grit is collected in the bottom of the basins
and transferred to one of the two Wemclone //1000-C hydrogritter units for
dewatering. The dewatered grit is collected and hauled to the City of
Garland landfill. The bar screenings and grit removed average 1200 Ibs./day.
The wastewater that has received pretreatment is pumped through the raw
water lift station for distribution into the biological and physical-chemical
treatment processes. The raw water lift station uses five pumps, two of
which are variable speed. The flow rate through the raw water lift station
during 1979 averaged 18.3 MGD, with a high flow of 30 MGD and a low flow of
9.5 MGD.
BIOLOGICAL TREATMENT PROCESSES
The biological treatment processes at the Duck Creek Wastewater Treat-
ment Plant begin with two primary clarifiers, Eimco Type-C clarifiers. Each
measures 75 feet in diameter, with a sidewall depth of 10 feet. The clari-
fiers are each equipped with two sludge rake arms.
Two primary-stage trickling filters follow the clarifiers. These are
designated as Eimco high-rate trickling filters, 140 feet in diameter with
a sidewall depth of 8.5 feet.
An Eimco intermediate clarifier follows the primary-stage trickling
filters. The intermediate clarifier is 110 feet in diameter with a sidewall
depth of 11 feet and equipped with a single sludge rake arm.
304
-------
Two secondary-stage trickling filters follow the intermediate clarifier.
Both are Eimco high-rate trickling filters, with 140 feet diameter and a
sidewall depth of 8.5 feet.
The secondary-stage trickling filters are followed by two final clari-
fiers. These clarifiers are 110 feet in diameter with a sidewall depth of
11 feet, equipped with two sludge rake arms.
The effluents from the final clarifiers flow by gravity into a wetwell,
which is located under the biological lift station. The effluents in the
wetwell are pumped by three turbine pumps to be mixed with the physical-
chemical treatment effluents at one of three possible points:
1. into the wetwell prior to ultra-high rate filtration.
2. prior to the granular activated carbon adsorption
3. prior to the disinfection basin
Sludges collected during primary, intermediate and final clarification
are pumped to the sludge dewatering facilities for conditioning, dewatering,
and disposal. These sludges are mixed with the physical-chemical treatment
sludges in the sludge equalization tanks prior to conditioning.
The biological treatment process was made operational in the Duck Creek
Wastewater Treatment Plant in 1962, at a designed treatment capacity of 10
MGD. A performance loss was noted at flows in excess of 7.5 MGD. The cur-
rent maximum daily flow rate through this process is now 7.5 MGD.^-'
PHYSICAL-CHEMICAL TREATMENT PROCESSES
Wastewater from the raw wastewater lift station is pumped to one of two
flash raising units on the south side of the chemical building. Each flash
mixing unit consists of two Lightnin 82-Q 7-1/2 hp mixers, where 140 mg/1
of lime, 35 mg/1 of ferric chloride, and 0.5 mg/1 of polyelectrolyte are
added to the wastewater. The wastewater with the chemical mix is flowed to
one of four 100 feet in diameter, 14 feet in depth clariflocculators. Total
retention time is 3 hours, with 30 minutes for flocculation and 2-1/2 hours
for settling. *• '
The sludges are accumulated by two sludge rakes at the bottom of the
clariflocculators and are pumped to the sludge dewatering facility. Floating
grease and scum is skimmed and pumped back into the chemical building for
incineration in one of two Walker Process Greaseburn incinerators. The cur-
rent grease loading is negligible, with only one furnace operating for one
day every four months.
After the wastewater passes over the weirs at the circumference of the
clariflocculators, it flows by gravity to one of the two recarbonation basins.
The recarbonation facility is composed of two 20 feet wide by 80 feet long
by 15 feet deep basins. Each basin is divided into two parts, one mixing
basin 24' in length, and one reaction basin, 56' in length. The mixing cham-
bers each have two Rexnord Envirex 5 hp turbine spargers for addition and
diffusion of carbon dioxide. A 13 foot high weir separates the mixing and
305
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reaction basins, forcing the wastewater upwards after it has received the
carbon dioxide. The wastewater then flows through the 56 foot long reaction
basin, passing over a final weir, and into a trough which connects both re-
carbonation reaction basins.
The design carbon dioxide dosage is 200 Ibs./MGD, which is supposed to
react with the clariflocculators effluents and lower the pH from 10.0 to
7.5-8.0. The lowered pH is most compatible with the filtration which follows
the recarbonation facility.
Carbon dioxide is stored in the liquid form on site in a 24-ton storage
unit equipped with an integral refrigeration unit. A dual vaporizer system
insures the system will not pass liquid carbon dioxide into the effluents in
the recarbonation basins.
The present situation, however, does not lend itself to the desired pH
reduction. Instead, the pH reduction has at best been a reduction by only
1.4 pH units.
The University of Texas at Dallas has begun an optimization study of
the recarbonation systems at the Duck Creek Wastewater Treatment Plant. A
series of laboratory and field experiments have demonstrated a lack of mass
transfer from carbon dioxide gas to the effluent liquid in the recarbonation
basin. This lack of mixing therefore resulted in an incomplete reaction be-
tween the carbon dioxide and the calcium carbonate in the wastewater. Cur-
rently, new diffuser systems are being tested in order to improve the overall
performance of the recarbonation facility.
After recarbonation, the effluents are allowed to flow by gravity flow
into two wetwell facilities, each 39 feet long by 22 feet wide by 30 feet
deep. These wetwells insure a continuous flow through the four ultra-high
rate sand filtration system pumps, each powered by 250 hp variable speed
electrical motors. The wetwells also provide a good mixing area for the
biological effluents if they are added to the physical-chemical effluents
prior to ultra-high rate sand filtration.
Filtration takes place in six Dravo ultra-high rate filters, each 16
feet in diameter and 16 feet high. The filters are designed to operate at
a maximum flow of 22.5 MGD, using 2-3mm diameter quartz filtering sand. The
bed depth is 5'6". The filters operate at 45 PSI. Backwash operations are
carried out automatically every 4.5 hours, or if head loss exceeds 10 PSI.
Filter backwash procedures last 15 minutes for the 4.5 hour backwash proce-
dures, and 3 minutes when headloss exceeds 10 PSI. All six ultra-high rate
sand filters feed into a central manifold, which leads to a 36", 58 feet tall
stand pipe, providing head for the following granular activated carbon ad-
sorption process and disinfection.
Although existing pipelines allow for the mixing of biological and
physical-chemical effluents prior to ultra-high rate sand filtration, this
procedure is utilized only in periods of climactic change where biological
growth in the trickling filters is sloughing off.
306
-------
If the biological treatment effluents were not joined with the physical-
chemical treatment effluents prior to ultra-high rate sand filtration, they
are blended immediately afterwards, prior to granular activated carbon
treatment.
The Zurn granular activated carbon adsorption process consists of ten
sets of two basins. In each set, one basin is for upflow, the other for
downflow. Each basin is 25 feet in diameter and- is 20 feet high. Nine of
the sets of two basins are on-line, while the tenth set is off-line for car-
bon regeneration or backwash procedures. The Zurn Upflow-Downflow granular
activated carbon adsorption process was selected because of its higher effi-
ciencies and lower initial and operational costs (4).
The granular activated carbon adsorption bed is 10' deep on top of a
1 foot deep gravel bed on top of the underdrain system. The design flow
through the system..,with 10 pairs in operation is 30 MGD, with a design flow
rate of 4.7 GPM/ft". There is approximately 118,000 Ibs. of granular acti-
vated carbon in each basin. The carbon loading rate is 975 Ibs./MGD. Back-
wash is accomplished at a rate of 15 GPM/ft , with air scouring at 5 CFM/ft.
The frequency of backwash procedures has not yet been determined. The granu-
lar activated carbon in use at the facility is ICI America's Hydrodarco 3000.
The granular activated carbon facility has not yet been operated in a
routine, on-line mode. The facility was operated for several weeks in 1978,
with underdrain damages evident in several basins. Since that time, Zurn
Industries has been involved in an in-house redesign, testing, and installa-
tion of new underdrain systems.
Carbon regeneration is scheduled for every 28 days, in an on-site Zimpro
multiple-hearth, gas-fired furnace. This furnace is capable of regenerating
80,000 Ibs./day at peak loading.
The Zimpro furnace has also not yet demonstrated its effectiveness.
Operated for a short period of time in 1978, it lost large amounts of granu-
lar activated carbon in the regeneration process. Since that time, the
Zimpro Corporation has redesigned several parts of the furnace system and
hopes to test its effectiveness in late spring, 1980. In 1978, the City of
Garland asked the University of Texas at Dallas to participate in studies to
optimize the granular activated carbon treatment at the Duck Creek Wastewater
Treatment Plant. In late spring, 1979, four pilot plants were designed and
constructed near the existing carbon facility at the Duck Creek Wastewater
Treatment Plant. These four 4.0 GPM pilot plants utilize upflow-downflow
granular activated carbon adsorption columns, with design specifications as
similar to the existing Duck Creek facilities as possible. Two pilot plants
utilize granular activated carbon (GAG), one on the effluents from the bio-
logical treatment processes, the other on the effluents from the physical-
chemical treatment processes. The other two pilot plants utilize the tech-
nique of pre-ozonated granular activated carbon (BAG), one on the effluents
from the biological processes, the other on the effluents from the physical-
chemical treatment processes. These pilot plants give the unique opportunity
to study and compare the effectiveness of granular activated carbon and pre-
ozonated granular activated carbon adsorption on the effluents from both
307
-------
biological and physical-chemical treatments. The data generated in the pilot
plant studies will assist in the operation and future development of the
full-scale operations. These pilot plant facilities have been operating
since early November, 1979, with close monitoring by analytical laboratory
testing for performance evaluation.
DISINFECTION
Disinfection is achieved by the addition of chlorine gas to the efflu-
ents as they pass into one of two parallel 130 feet long by 35 feet wide by
16 feet deep disinfection basins. Each basin is designed for a minimum of
thirty minutes residence time at a flow of 30 MGD.
DISCHARGE
Discharge is via a 200 yard long, 48" pipleine from the disinfection ba-
sins into Duck Creek. Duck Creek continues for approximately one mile, and
flows into the East Fork of the Trinity River just below the dam at Lake Ray
Hubbard. The Trinity River flows southward for approximately 300 miles into
West Bay, near Galveston, Texas and the Gulf of Mexico.
SLUDGE HANDLING AND DISPOSAL
The sludges removed from the biological and physical-chemical treatment
processes are combined in two 17 feet in diameter, 9 feet tall sludge equali-
zation tanks. These tanks each provide a total of 18 hours residence time
for the sludges. Two 1 million gallon holding tanks, formerly used as anaer-
obic digesters, provide up to 30 days of sludge storage for periods of peak
flow.
Sludges are pumped from the holding tanks into a 1100 gallon mixing tank
at the rear of the dewatering facility. The sludges are conditioned with
varying dosages of lime, ferric chloride, and polyelectrolyte.
After conditioning, the sludges are pumped into one of four Envirotech
Model 52 sludge presses. The press will dewater the 6-7% solids entry sludge
to a final sludge cake of 35-40% dry weight. The capacity of the sludge
presses has been demonstrated at 130,000 Ibs./day on a dry weight basis. The
pressed sludges are dropped into large disposal containers and then hauled,
along with the grit and screenings from the pretreatment stage by trucks to
the City of Garland landfill operation located 20 miles northeast of Duck
Creek Wastewater Treatment Plant. Operations showed the 1979 average sludge
removal to be 90,000 Ibs./day on a dry weight basis. (-")
DISCUSSION
As mentioned earlier, several areas of treatment at the Duck Creek
Wastewater Treatment Plant are not yet fully operational. The physical-
chemical treatment process is not yet operating in the manner it was designed.
As long as recarbonation is incomplete, the efficiency of the operation will
remain inadequate. Without the granular activated carbon adsorption facility,
308
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TABLE 3 ESTIMATED MAJOR PROCESS UNIT REMOVAL EFFICIENCIES (averaged)
u>
o
Process Unit
Equalization Basin
Biological Processes
Physical-Chemical
Processes
Ultra-High Rate
Sand Filters
Carbon Adsorption
Plant Outfall
Monitoring Average Daily
Parameter Flow, MGD
BOD5
COD 20
TSS
BOD5
COD 7 , 5
TSS
BODs
COD 12.5
TSS
BOD5
COD 12 . 5
TSS
BOD5
COD 20
TSS
BOD5
COD 20
TSS
Influent
Level, mg/1
260
560
233
168
410
296
168
410
296
56
100
50
28
64
17
10
20
10
Effluent
Level, mg/1
168
410
296
19
45
8
56
100
50
40
83
14
10
20
10
10
20
10
% Removal
35
27
**
89
89
97
67
76
83
29
17
72
64
68
86
96
96
96
** Biological activity is responsible for increased TSS level.
-------
TABLE 4 ACTUAL MAJOR PROCESS UNIT REMOVAL EFFICIENCIES (1979 averaged)
Process Unit
Equalization Basin
Biological Processes
Physical-Chemical
Processes
Ultra-High Rate
Sand Filtration
Carbon Adsorption
Plant Outfall
Monitoring
Parameter
BOD5
COD
TSS
BOD5
COD
TSS
BOD5
COD
TSS
BOD
COD
TSS
BODr
3
COD
TSS
BOD5
COD
TSS
Average Daily Influent
Flow, MGD Level, mg/1
239
18.5 540
233
206
7.5 450
206
206
11 450
206
74
11 201
41
** NO DATA AVAILABLE
42
18.5 138
22
Effluent
Level, mg/1
206
450
206
19
84
18
74
201
41
70
154
25
% Removal
14
17
12
91
81
91
64
55
81
5
23
39
82
74
91
** No operational data is available on the carbon adsorption facility. No operations took place during
1979.
-------
STATE OF TEXAS DISCHARGE PERMIT
Biological Oxygen Demand, 5 day (BOD^)
Chemical Oxygen Demand (COD)
Total Suspended Solids (TSS)
Fecal Coliform Bacteria
Chlorine Residual
PH
Maximum Discharge Flow
10 mg/1, monthly average
15 mg/1, 7-day average
none
10 mg/1, monthly average
15 mg/1, 7-day average
200/100 ml sample, monthly average
400/100 ml sample, 7-day average
1.0 mg/1 after 20 minutes contact time
6.0 - 9.0
30 MGD, monthly average
60 MGD, any single day
-------
the effluents discharged from the plant will not reach the desired COD and
BOD.
Examining the anticipated removal efficiency data proposed by the design
engineers as shown in Table 3, a stepwise treatment process with high removal
efficiency is noted. The operational data from 1979 found in Table 4 indi-
cates poor treatment efficiency in the physical-chemical processes. Without
optimization of physical-chemical treatment and 'ultra-high rate sand filtra-
tion, and the use of granular activated carbon adsorption, the effluent dis-
charges from the plant will not consistently be within the discharge permit
levels.
CONCLUSIONS
The upgrading of the Duck Creek Wastewater Treatment Plant is not yet
complete. It is expected that when the facility is fully operational the
effluent quality will be within the required 10 mg/1 of BOD and 10 mg/1 of
SS, resulting in a total treatment removal efficiency of 97%. The completion
of these facilities, along with the optimization of the physical-chemical
treatment processes will result in the treatment of the combined municipal-
industrial wastewater to a level suitable for discharge permit requirements.
REFERENCES
1. Forrest and Cotton, Inc. (1971). Engineering design report on Garland
wastewater treatment facilities, Duck Creek plant expansion.
2. McDuff, D.-P. and Chiang, W. W. J. (1972). Physical-chemical treatment
design for Garland, Texas. Applications of new concepts of physical-
chemical wastewater treatment.
3. Forrest and Cotton, Inc. (1976). Operations and Maintenance Manual Duck
Creek Wastewater Treatment Plant.
4. Strudgeon, G. E. and Carens, B. (1975). Upflow-downflow carbon adsorp-
tion. AIChE Conference, Los Angeles, California.
5. City of Garland, Texas (1980). Annual report of laboratory operational
data, January 1 to December 31, 1979.
312
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PB93-142356
THE TREATMENT OF COTTON WASTE
IN THE MERSEY BASIN
G.M. Doughty
MSc BSc(Eng) ACGI DIG MIWES
Department of Civil Engineering
Sheffield City Polytechnic
Pond Street
Sheffield SI 1WB
England
ABSTRACT
Many of the streams of North West England, the traditional home of the
UK cotton industry, are still heavily polluted by industrial discharges.
Severe pollution of the River Goyt, a tributory of the Mersey, results from
a cotton processing effluent, much of which is treated in admixture with do-
mestic sewage at Whaley Bridge Effluent Treatment Works (E.T.W.). Although
the works was extended in 1967 and is not hvdraulically over-loaded, the
acceptance of strong liquors from the Kiering operation of the cotton pro-
cessor has resulted in a gross organic overload. After hydraulic balancing
and neutralisation at the trade premises, a highly coloured liquor with a BOD
estimated at SOOOmgL is sewered to the E.T.W. In current extension of the
E.T.W. by North West Water Authority, conventional biological treatment is to
be upgraded to high-rate filters followed by oxygen activated sludge (UNOX).
To aid dilution of the trade effluent, two outdated downstream E.T.W.'s are
to close and their process flows pumped upstream to Whaley Bridge. A high
degree of flexibility is incorporated in the design with only the highly
polluted flows passing through all the biological stages. The extended works
have been designed with the aim of achieving a 30/20 effluent standard, al-
though further development work is considered necessary to eliminate high
colouration.
INTRODUCTION
When the Industrial Revolution came to Britain the first ma-jor industry
was textile manufacture. Its factories were thus sited at the optimum loca-
tion for processing and trade. Textile treatment requires copious volumes of
soft water for wet processing operations such as scouring, bleaching, dyeing
and printing and this consideration was the most significant factor in the
siting of the early factories and subsequent establishment of manufacturing
centres.
313
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Prime sites were found beneath the Pennines of the North of England and
the textile manufacturers became established in the upper and middle reaches
of the river valleys of Lancashire, Yorkshire and North Derbyshire, Wool
processing grew to become the dominant industry of much of Yorkshire, locat-
ing on rivers flowing out to the North Sea. The cotton industry, on the
other hand, centred on the North West city of Manchester with its wet process-
ing operations being carried out on the west flowing rivers, mostly those
draining into the upper Mersey basin.
Intensive industrialization of this nature inevitably led to conditions
of gross pollution which, in many cases, still remain to be improved today.
The Rivers Irwell and Mersey and many of their major tributaries carry ex-
cessive loads of wastewater, much of which originates from trade premises.
Lumb (1) described these rivers in 1965 as among "the most heavily worked
in the UK and probably in the world."
The textile "industry contributed an aggregate daily volume of 140,000 m
of directly discharging effluent from 59 premises in 1964 into the Mersey
basin (1). Contraction of the industry and/or the diversion of discharges to
sewer had reduced the number of direct discharges to eight by 1978 with an
aggregate input of 36,000 m (2). Hazel (3) estimated that in 1978 only 12%
was discharged to stream following treatment on site with the remainder being
discharged to sewer untreated or following pre-treatment such as settling or
balancing.
The upper Mersey catchment drains to the Manchester Ship Canal where
pollution problems are aggravated by sluggish flow in a deep artificial
channel resulting in enhanced settlement and low re^aeration potential.
EFFLUENTS FROM COTTON PROCESSING
Liquid effluents result from chemical treatment which may conveniently
be separated into fibre preparation and material colouration and finishing.
Preparatory processes remove unwanted substances from the raw cotton while
colouration and finishing involves dyeing or printing and the incorporation
of finishing agents such as crease or flame retardants.
Much effort continues to be made internationally into the removal of
dyewastes (4) (5) and increased stringency over discharges has led to an
awareness of effluent problems when selecting dydstuffs and process methods
(6).
Table 1 shows quoted characteristics of mrxed effluents derived from the
complete processing of cotton. The variations displayed show that operations
differ markedly and, indeed, consideration of mixed effluents in this way
may not be the most appropriate method of assessing their effects and treat-
ment requirements.
314
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TABLE 1 CHRACTERISTICS OF MIXED COTTON EFFLUENTS
Quantity
Discharged _-,
Reference (m /kg cotton) (mgl ) pH
Lumb (1) 250- 400 7-9
(UK)
Parish (7) 0.06-0.5 100- 500 8-12
(UK)
Gardiner &
Borne (12) 200-1800 4-12
(UK)
Anderson &
Wood (8) (AUS) 0.2 600-1000 10;
Many establishments do not carry out a full range of processing and it is
useful to refer briefly to the type of operations carried out to isolate
those preparatory processes which produce difficult effluents. It is these
processes which produce difficult effluents. It is these processes which
appear to cause the most intractable problems in the Mersey Basin.
Raw cotton fibres contain up to 10% w/w of fats and waxes and are sub-
ject to kiering (scouring) by boilina with sodium hvdroxide and sodium car-
bonate, often under pressure. A large proportion of the impurities are thus
removed producing a kier liquor effluent described by Best (9) as of small
volume but strongly alkaline and with a high organic load. Kier liquors are
often costly and difficult to treat to a reasonable standard. Table 2 shows
several analyses of kier liquors showing general agreement of their stronely
alkaline nature and extremely high organic load in the U.K. and Australian
effluents.
After scouring, the cotton is bleached using hypochlorite, chlorite, or
hydrogen peroxide to remove or destroy natural colouring matter. It is usual
for the kiering and bleaching operations to be carried out on the same prem-
ises although the respective effluents may be kept separate for treatment and
disposal purposes.
315
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TABLE 2 CHARACTERISTICS
OF KIER LIQUORS
Reference
Lumb (1)
(UK)
Wheatland
(10) I (UK)
Wheatland
(10) II (UK)
U.S.H.E.W.
(ID (US)
Anderson &
Wood (8)
(AUS)
Quantity
Discharged
(m /kg cotton)
0.003
-0.017
0.004
BOD-5
(mgl X)
7100
-11000
10650
6650
680^
2900
8000-
14000
PV-4hr
(mgl ) pH
3500 12-13
-6000
8850
6000
10^13
13.5
Others
(mgl )
Alkalinity
16750
(as CaCO )
Sodium
11000-13000
TREATMENT OF COTTON EFFLUENTS
Successive legislation from the 1937 Drainage of Trade Premises Act and
resulting practice has maintained that, where feasible, trade effluents are
best treated in admixture with domestic sewage in municipal treatment plants.
Re-organization of the water industry in England and Wales in 1973 created
larger units with the resources to adequately plan and expedite wastewater
treatment. Rhoades (13) suggests that treatment at a municipal works with
suitable control is the best course of action for textile wastes. Australian
practice involves primary treatment on site with subsequent discharge to
sewer (8). The tendency in the Mersey Basin in recent years has been to di-
vert more textile effluent to sewer and, in most cases, a satisfactory efflu-
ent has been achievable.
3 -1
Wheatland (10) describes the effect of adding 3800 m day of mixed tex-
tile effluent on the performance of a U.S. biological (trickling) filter
plant previously treating only domestic sewage. It can be seen that although
the volumetric loading increased by less than 10% the increased organic load-
ing and loss of efficiency of the primary unit led to a doubling of load
upon the biological stage. Since this load is about five times that normally
used for a UK plant (no recirculation) it is not surprising that the reduc-
tion in effluent quality resulted.
316
-------
Volumetric Load
(m day )
BOD of raw sewage
(nigl'1)
BOD removal in primary
sedimentation (%)
Loading on filters
(kgBOD/m day)
Overall BOD removal
(%) "
BOD of final effluent
(mgl )
Before addition
of textile
effluent
40.9
290
27
0.30
83
49
After addition
of textile
effluent
44.7
450
18
0.59
79
95
Indeed, if textile wastes are to be treated by aerobic biological treat-
ment, nutrient requirements may indicate that an admixture with domestic
sewage is desirable. Many enzymes require specific activators to satisfac-
torily accomplish reaction. One of the most important activators is the phos-
phate ion which may be deficient in textile waste whereas it reaches rela-
tively high concentrations in domestic sewage (7) (10). The beneficial
effects of nutrient balance in conjunction with buffering and dilution are
therefore obtained by treatment in admixture with domestic sewage.
Many textile wastes have a high pH and neutralization may be necessary
prior to discharge to sewer. A pH level of up to 9.5 may be tolerated for
wastes applied to biological filters provided alkalinity levels are not ex-
cessive (10). Recirculation of filter effluent will provide some dilution
while CO production within the filter will afford further neutralization.
Suspended culture processes may tolerate higher pH values in the effluent
because of the inherent buffering action of completely mixed plants. How-
ever, the pH of the activated sludge mixed liquor should not exceed 8.5 (10).
Treatment of Kier Liquors
It is not surprising that kiering effluent, with such high organic con-
centrations in conjunction with extreme alkalinity (as shown by table 2), has
been the subject of considerable attention.
Treatment methods may conveniently be divided into two types, those
where the concentrated liquor is treated or pre-treated separately from any
other effluents, and those where the concentrated liquor is treated or pre-
treated separately from any other effluents, and those where dilution and/or
mixing with other waste streams followed by more conventional treatment
is practiced.
317
-------
Wheatland (10) suggests that kier liquors may be sufficiently strong
to consider evaporation followed by incineration of the residues. Both
Franklin (14) and Little (15) discuss the neutralization of strong alkaline
wastes with flue gases in packed towers. Sulphuric acid has also been used
as the neutralizing agent (15) but Gardiner (12) warns of the dangers of ex-
cessive sulphate discharge to sewer causing disruption of concrete.
A series of experiments carried out on kier liquors at the Water Pollu-
tion Research Laboratory are reported by Wheatland (10). Partially neutral-
ized liquors with an average BOD of 2200 mgl~ and 4 hour P.V, of 900 mgl~
were subjected to continuous anaerobic digestion at 30°C. For retention
periods between 2.6 and 6.1 days, average BOD removal was 72% and P.V. re-
moval 54%. Although the high temperature of kier liquor effluent is advan-
tageous to digestion the probable requirement for subsequent aerobic pro-
cessing has meant that little development in this area has taken place.
Aerobic- treatment of diluted neutralized liquor in a laboratory scale
activated sludge plant was also carried out at W.P.R.L, (10). Results showed
BOD removal efficiencies of 95% at loading rates of 0.46 kg BOD/m day,
slightly lower than those used in conventional UK domestic treatment. Re-
duction of P.V. was only 35%, however, suggesting that a substantial propor-
tion of organic matter may not be easily degradable by activated sludge.
Further reduction of P.V. was achieved by acidifying with sulphuric acid
down to pH2 where substantial precipitation of organic matter takes place up-
on settlements as shown by table 4. The characteristic kier liquor colour
which tends to be virtually unaffected by aerobic treatment is shown to be
very effectively reduced by acidification and settlement.
Colour removal may also be achieved by chemical oxidation. This may be
effected by using chlorine as ozidizing agent although concentrations up to
750 mgl may be required, making the operation costly and difficult (10).
Additionally, the products of chlorinating such wastes are often non-
biodegradable and chlorinated organics generally are the subject of much cur-
rent discussion as to potential health hazard. Alternative oxidizers are
hydrogen peroxide and ozone which, although more expensive, give rise to no
undesirable compounds. Additionally it is reported by Lumb (1) that the use
of a peroxide bleach process reduces the BOD of the resulting liquor by
50-90% compared with the traditional caustic kier scour.
318
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TABLE 4 EFFECT OF ACIDIFICATION & SETTLEMENT
pH value
after acid
addition
8.2*
3.5
2.8
2.4
2.0
ON EFFLUENT FROM TREATMENT OP
KIER LIQUOR IN ACTIVATED
Volume of sludge
after 1 hr settle-
ment (%)
2.5
8.5
13.0
15.0
16.3
1 DILUTED, NEUTRALIZED
SLUDGE PLANTS (10)
Supernatant Liquor after 1 hr
settlement
4-hr Opticalf
P.V. - Colour Density
300 Dark brown 1.2l|
210 Dark amber 1.03
128 Light amber 0.43
114 Light amber 0.33
107 Light amber 0.30
before any acid addition
using l-cm"cell, blue filter
value for 1 : 1 dilution in distilled water
THE COTTON INDUSTRY IN THE MERSEY BASIN
2
The Mersey Basin drains a catchment of some 4585 km of the heavily
industrialized North West of England into the Irish Sea. It is the upper
parts of this catchment drained by the non-tidal Mersey (680 km ) and the
Irwell (710 km ) which attracted the cotton processors and their resultant
effluents.
Figure 1 shows the river quality classifications at selected points as
determined by North West Water Authority (2). The classifications are on a
scale 1-4 recommended by the U.K. National Water Council (16), Classes 1A and
IB referring to high quality waters (eg BOD <2) and Class 4 waters being
grossly polluted and likely to cause nuisance. It can be seen that both the
Irwell and the non-tidal Mersey are suffering serious pollution prior to en-
try to the Manchester Ship Canal.
Direct Discharges
Published direct discharges into the upper Mersey basin from textile
processors are detailed in table 5 and their locations, indicated by number
on figure 1, are now confined to two principle sections, the upper Irwell
(manufacturers 1-4) and the Goyt(manufacturers 5-8).
Those manufacturers on the upper Irwell are all located on essentially
unpolluted tributory streams which suffer gross pollution below the trade
waste outfall. It is apparent that each trader regularly discharges efflu-
ent with pollutant concentrations in excess of the consented values with the
possible exception of Whitecroft (no. 4), Besides having the largest dis-
charge in volumetric terms, however, Whitecroft enjoys unusually relaxed
quality standards and is the largest polluters of the four traders in terms
of organic load.
319
-------
A Textile works discharges
xi Whaley Bridge E.T.W.
2 New Mills E.T.W.
$ Saddleworth E.T.W.
012345 10
Kilometres
4 River Quality Classification
Figure 1 The Upper Mersey Catchment
320
-------
Whitecroft's Whaley Bridge discharge (No. 8) into the Goyt has a rela-
tively satisfactory performance in terms of consent conditions but again has
the largest volumetric flow. Most of Whitecroft's process flow is taken from
the upstream Goyt water which is of a suitably high quality for potable sup-
ply abstraction. In so doing, the factory often removes the bulk of the flow
of the Goyt causing available dilution for trade effluent to be less than 1:1
and often negligible under summer low flow conditions. The inevitable result
of such a discharge and, indeed, more pertinently, of such consent conditions,
is a Class 4 grossly polluted stream.
It is of interest to compare the position of Whitecroft's Whaley Bridge
operation with the Strines factory of Tootal (No. 6), which is situated some
four kilometres downstream. Whitecroft carries out elementary treatment
(balancing tanks) prior to its direct discharge with stronger effluent li-
quors discharged to sewer. Tootal is subject to a similar level of consent
condition on the discharge from an activated sludge treatment plant treating
the entire process effluent after neutralization and hydraulic balancing.
However, the available dilution at the Tootal outfall is around 20:1 and no
change in river quality classification results from the discharge. Addition-
ally, Tootal abstracts process water from the Goyt but, without the benefit
of an unpolluted river source, must suffer additional costs to treat to an
acceptable standard for process use. Modifications to the Tootal plant
following its poor operation in 1978 (Table 5) resulted in a much improved
performance in 1979. Effluent quality as derived from Water Authority
samples gave mean parameter values in 1979 of 25 mgl~l SS, 17 mgl"-*- BOD,
44 nigl"1 4 hr PV, and 7.8 pH (17).
The two other direct discharges on a tributary of the Goyt (Nos. 5 and
7) were consistently outside consent conditions and were both the subject of
successful prosecution by the Water Authority in 1978 under statutory pollu-
tion control legislation.
321
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TABLE 5 TEXTILE EFFLUENT DISCHARGES TO SURFACE WATERS 1973 (16)
Manufacturer
1
Ramsbottora Co.
(Bleaching and
Dyeing)
->
Tootal,
Rawtenstall
(Printing and
Dyeing)
3
Viyella,
Ramsbo t Cora
(Dyeing)
4
Vhicecrofc ,
Haslingden
(Bleaching and
Dyeing)
5 t
Dorma, Chinley
(Printing)
6
Toocal, Scrines
(Printing and
Dyeing)
7
Wardle, Chinley
(Dyeing)
3
Vhicecrofc ,
Whaley Bridge
(Bleaching and
Dyeing)
9*
Selmonc, Bolcon
(Bleaching and
Dyeing
LO*
Mycocic, WhiCworCh
(Princing and
Dyeing)
11*
Roe Acre ,
Heyvood (Dyeing
and Finishing
Receiving
Stream i
Classification
Trib. Irvell
Upstream IE
Downscream 4
Trib. Irvell
Upstream 1A
Downstream 4
Trib. Irvell
Upstream IB
Downstream 4
Trib. Irvell
Upstream 1A
Downstream 4
Trib. Goyc
Upstream 13
Downscream 4
Goyt
Upstream 3
Downstream 3
Trib. Cove
Upstream 4
Downscream 4
Goyc
Upstream 1A
Downscream 4
Trib. Irvell
Up s cream 1
Downscream 2
Trib. Irwell
Trib. Irwell
Upstream 4
Downscream 4
Volume
'-i-'d)
Consented
3550
Actual
450
ConsenCed
5900
Actual
5900
Consented
900
Actual
450
ConsenCed
8430
Actual
7390
Consented
1590
Actual
1590
Consented
7950
Actual
4540
Consented
1270
Actual
2270
ConsenCed
13300
Actual
13640
Consented
Actual
6820
ConsenCed
1820
Accual
1820
ConsenCed
273
Actual
370
Si;
?ar
SS
Consent 40
Sample
nean 138
Consent 30
Sample
mean 73
Consent 30
Sample
mean 272
Consent 60
Sample
mean 38
Consent 40
Sample
mean 131
Consent 30
Sanole
^ean 219
Consent 40
S amo le
-,ean 202
Consent 40
Sd-oie
T-.e an 29
Consent 30
Sample
mean 116
Consent 40
Sample
mean 99
Consent 30
Sample
mean 64
n i f i c an t 0
ar-ecers Cm
3CD ?V
40 60
453 177
20 40
43 55
20 60
54 90
1-0 120
101 34
-.0 SO
27' 160
40 40
79 90
40 60
146 100
30
1 1
20 40
480 107
40 60
364 233
20 40
39 63
ualicv
si-1)'
oH
5-9
10.8
5-9
3.7
5-9
7 . 4
5-9
7. 5
5-9
6.2
5-9
7.9
5-9
7.2
5-9
5. 7
5-9
10.7
5-9
3.3
5-9
7.6
* 1976 daca. Effluencs now diverted to sewer.
1977 data. So oublication Authorized in 1973.
322
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Discharges from E.T.W.'s Treating Textile Wastes
TABLE 6 WATER AUTHORITY E.T.W. DISCHARGES (2) (18)
E.T.W.
Receiving
stream &
Classification
Year
Actual D.W.F.
(m3/d) % of Mean* (mgl"
design BOD SS
1
Whaley Bridge
2
New Mills
3
Saddleworth
R. Goyt
Upstream 3
Downstream
R. Goyt
Upstream 3
Downstream
R . Tame
-Upstream 3
Downstream 3
1976
1978
1976
1978
1976
1978
227CT
3450
2120
2120
4440
3890
66
101
180
180
58
51
78
70
104
277
67
30
47
55
96
107
57
32
* All works subject to consent conditions of 20 mgl BOD and 30 mgl~l SS.
The sequence of major discharge points into the upper section of the
R. Goyt is shown in Figure 1. One kilometre below the Whitecroft trade dis-
charge, the river receives the effluent discharge from the Whaley Bridge
E.T.W. which treats the neutralized concentrated kier liquors derived from
Whitecroft in admixture with domestic sewage. Although commissioned as late
as 1967, the works, operating with conventional biological filters, has con-
sistently failed to function satisfactorily.
Data relating to the works performance in recent years is presented in
Table 6, showing that despite being hydraulically underloaded for the most
part, a poor effluent is discharged. This effluent is additionally highly
coloured because of poor colour removal from the kier liquors.
A rather better performance has recently been obtained from the
Saddleworth E.T.W. (Table 6) which discharges into the Tame, the other major
tributary of the Upper Mersey. Saddleworth also treats kier liquors in ad-
mixture with domestic sewage,but two-stage biological treatment is used.
After high-rate activated sludge treatment, the process stream is applied to
low-rate biological filters. The works, which was last extended in 1972, is
also hydraulically underloaded. Experiments currently proceeding are aimed
at improving nutrient levels to the filters.
The relative improvement in the Tame in recent years compares with the
condition of the Goyt which, despite the closure of several major direct dis^
charges on an important tributary stream, has shown little overall change.
Table 7 demonstrates the alteration in pollution load since 1964 when Lumb (1)
estimated that three-quarters of the BOD load in both rivers was due to tex-
tile effluents.
323
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TABLE 7 COMPARISON OF THE RIVERS TAME AND GOYT
River
Goyt
with
Tame
with
(.above confluence
Tame)
(above confluence
Goyt)
Year
1964-5
1972-3
1976
1977
1978
1964-5
1972-3
1976
1977
1978
Mean values
COD BOD
(1)
(19)
(2) (18)
(2)
(2)
(1)
(19)
(2) (18)
(2)
(2)
36
33
33
39
98
71
64
61
.0
.8
.8
.4
.0
.2
.5
.8
8
6
5
37
16
14
.1
.4
.8
.0
.3
.6
(mgl X)
BOD (ATU)
4.
5.
10.
9.
8.
0
9
1
6
6
THE UPPER GOYT PROBLEM
The pollution of the upper Goyt is compounded downstream of Whaley
Bridge by poor quality effluents from outdated effluent treatment works.
Table 6 shows the extremely poor quality of the effluent from the worst
offender of these, the New Mills E.T.W. This works was last extended in 1927
and suffers from inadequate capacity and breakdown of the trickling filter
media. Although no textile waste is received by New Mills E.T.W., the in-
fluent includes a significant contribution from a confectionery manufacturer
and has an organic load somewhat higher than normal domestic levels.
In 1970, consulting engineers were engaged by New Mills Urban District
Council* to prepare outline design for a new works to replace the New Mills
E.T.W. and a smaller outdated nearby works. The following year, only three
years after the commissioning of Whaley Bridge E.T.W., Mersey and Weaver
River Authority* engaged the same consultants to investigate the feasibility
of transferring sewage from Whaley Bridge to a central works at New Mills, a
scheme which the Authority considered to be the most desirable solution to a
deteriorating situation. The consultant reported (20) that major problems at
Whaley Bridge resulted from the discharge to sewer from the Whitecroft fac-
tory of an effluent with a BOD of up to 8000 mgl . By inspecting flow rec-
ords at the trade premises, the-consultants ascertained that in late 1971,
the trade flow was around 450 m /day whereas an allowance of only 140 m /day
had been made in the E.T.W. design. This higher trade flow had resulted in
an increase in organic loading by a factor of 2.6 in only four years (19).
In 1977, North West Water Authority gave formal notice that the concept
of a new regional works at New Mills had been abandoned and that Whaley Bridge
E.T.W. was to be extended to cater for the abandonment of New Mills E.T.W.
and for the increased trade discharges.
*Prior to 1974 sewage treatment was carried out by elected Local Authorities
and river quality control was the responsibility of River Authorities. In
1974, both funcations (and water supply) came under the auspices of the
newly-created North West Water Authority.
324
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The Current Whaley Bridge Scheme
There are two obvious disadvantages to the Water Authority scheme to
improve Whaley Bridge E.T.W. rather than build a new central works at New
Mills. The previous scheme had essentially gravity flow to New Mills, whereas
a pumping main will carry what is hydraulically the larger proportion over a
distance in -excess of 2 km. Additionally, when the New Mills sewage is
added to the Whaley Bridge component it will reduce the available dilution
at the Whaley outfall to about 6 to 1. Over 10 to 1 dilution would be avail-,
able to a regional New Mills E.T.W. with a similar throughput.
The scheme, costing some 63 m at 1978 prices, includes two stage biolog-
ical treatment as did the previous consultant's recommendation for a new
New Mills works (19). High rate (roughing) biological filters were proposed
as pre-treatment to standard rate filters with re^circulation at New Mills.
Roughing filters will also be employed in the Whaley Bridge plan by adapting
and augmenting the existing filters, with pure oxygen activated sludge
treatment following. Describing studies on mixed textile waste, Wheatland
(10) reports that the best BOD removal efficiencies were achieved where the
waste was mixed with domestic sewage and passed through roughing filters
followed by activated sludge treatment.
The proposed Whaley Bridge extension provides a high degree of flexi-
bility with the ability to keep the two streams separate through much of the
works. The design loadings are shown in Table 8 with some 70$ of the highly
polluted Whaley Bridge stream passing through the roughing filters. The
carbohydrate-rich New Mills stream is then mixed with the total Whaley Bridge.
flow affording dilution and nutrient-enrichment prior to the UNOX pure oxygen
activated sludge plant. Assuming BOD removal efficiencies of 85% and 95%
in the roughing filters and IMOX respectively, a final effluent BOD of 20
mgl is obtainable. The expected removal rate on the filters may appear
optimistic but a loading rate of only 0.36 kg BOD/m day is to be applied,
about double the conventional (low-rate) UK loading for normal domestic
sewage on a filter with 1 : 1 re-circulation facility.
325
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TABLE 8 DESIGN LOADINGS TO PROPOSED EXTENDED WHALEY BRIDGE E.T.W.
Process Stream
Whaley Bridge stream
(primary settled)
(a) Influent to filters
Filter effluent
(assuming 85%
BOD removal)
(b) Bv-passing filters
Ex W.B. stream to UNOX A.S.
New Mills stream (primary
settled)
Influent to UNOX A.S.
Final Effluent
(assuming 95%-
BOD removal in UNOX)
D.W..F.
(m /day)
3318
2318
2318
1000
3318
4636
7954
7954
(mgl )
1182
1182
177
1182
480
323
388
20
BOD
(kg BOD/day)
3923
2741
411
1182
1593
1497
3090
159
The plant improvements are expected to have little effect on effluent
colouration and further experimental work is proceeding to this end. As de-
scribed earlier, any ameliorative provision will involve considerable further
expenditure. An effluent target of 20 mgl BOD is not a particularly am-
bitious one for an available dilution of 6 to 1 and may reasonably be regard-
ed as little more than a holding operation in times of considerable pressure
on public funds, although it is envisaged that more of the Whitecroft direct
discharge may be diverted to sewer in the future.
The reader may have some justification in questioning the wisdom of
allowing the highly polluting kier liquors to sewer rather than enforcing
full treatment or more sophisticated pre-treatment at the trade premises.
The ansxcer to that may lie rather more with the legal and financial commit-
ments made between the trader and the Water Authority's predecessors than
with consideration of technical feasibility.
ACKNOWLEDGEMENTS
The author wishes to express thanks to the Sheffield City Polytechnic
for permission and assistance to present this paper and to Mr. Michael
Lawford of Tootal Ltd and Mr. Bill Hadfield and other staff of the North West
Water Authority for their assistance and helpful advice in its preparation.
326
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REFERENCES
1. Lumb, C. Pollution by Textile Effluents in the Mersey Basin, Shirley
Institute pamphlet no. 92, 60-76, Manchester, 1965.
2. Water Quality Review 1978, North West Water Authority, Warrington,
1979, 345 pp.
3. Hazel, B.C. Water: An Expensive Solvent, J. Soc Dyers & Colourists,
94_, 7, 289-293, 1978,
4. Waters, B.D. Treatment of Dyewaste, Wat. Pollut. Control, 78, 1,
12-26, 1979.
5. Weeter, D.W. & Hodgson, A.G. Dye Wastewaters; Alternatives for
Biological Waste Treatment, Proc. 32nd Industrial Waste Conference,
Purdue Univ., 1-9, 1977-
6. Brooks, A. Textile Effluent: A closer look at the Problem, Knitting
International, 81, March, 81-84, 1974.
7. Parish, G.J. Textile & Tannery Wastes, Ch. 14 in Treatment of
Industrial Effluents, (Eds. Callely, A.G. Foster, C.F. and Stafford,
D.A.) Hodder and Stoughton, London, 1977, 378 pp.
8. Anderson, C.A, & Wood, G.F. Textile Effluents and their treatment,
Textile Journal/Australia, 48, 10, 42-50, 1973.
9, Best, G.A. Water Pollution and Control, J.Soc. Dyers and Colourists,
_90_, 11, 389-393, 1974,
10. Wheatland, A.B. Treatment of Waste Waters from the Textile Industry,
Shirley Institute pamphlet no. 92, 35^-59, Manchester, 1965,
11. An Industrial Waste Guide to the Cotton Textile Industry, U, S, Dept. of
Health, Education & Welfare, 1959.
12. Gardiner, O.K. and Borne, B.J. Textile Waste Waters: Treatment and
Environmental Effects, J. Soc. Dyers and Colourists, 94, 8, 339-348,
1978.
13. Rhoades, J.B. Pollution Problems - Especially in Relation to the
Textile Industry, J. Bradford Textile Soc., 34-38, 1975.
327
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References Continued
14. Franklin, J.S., Barnes, K.and Little, A.H, Textile Effluent Treatment
with Flue Gases, International Dyer & Printer, 142, 427, 1969.
15. Little, A.H. The Treatment and Control of Bleaching and Dyeing Wastes,
Wat. Pollut. Control, 68_, 2, 178-189, 1969.
16. River Water Quality, The Next Stage; Review of Discharge Consent
Conditions, National Water Council, London, 1977, 10 pp.
17. Personal Communication, M.R.V. Lawford, Effluent and Water Treatment
Manager, Tootal Ltd., January, 1980.
18. Water Quality Review 1976, North West Water Authority, Warrington,
1977, 300 pp.
19. Annual Report, Mersey & Weaver River Authority, Warrington, 1973.
20. Ward, Ashcroft and Parkman, Feasibility Report on the Transfer of
Sewage from Whaley Bridge to New Mills, Liverpool, 1972, 38 pp.
328
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PB83-142364
CASE STUDY OF A POTATO CHIP PRODUCER
DISCHARGING TO A SMALL MUNICIPAL TREATMENT SYSTEM
A. W. Wilson
Manager, Environmental Engineering
Reid, Crowther & Partners Limited
Sixth Floor, 220 Duncan Mill Road
Don Mills, Ontario
Canada M3B 3J5
ABSTRACT
An investigation was made of the causes of chronic upset conditions at
a small municipal treatment plant receiving a large proportion of potato
chip processing wastewater. The investigation encompassed a review of
effluent loadings from the potato chip production process, improvement of
pre-treatment facilities, and separate treatment of the caustic waste
generated during cleaning of the fryers. Not all of the problems at the
sewage treatment plant were due to the potato processing wastes. Periodic
hydraulic surging caused by a sewage pumping station was impairing the per-
formance of the primary treatment system. A marginal nutrient limiting
condition in the secondary section of the treatment plant was identified,
and an appropriate operating range for the process control parameters was
recommended. The importance of collecting representative composite samples
to provide an accurate reflection of the loadings on the treatment plant
was noted.
INTRODUCTION
The Hostess Food Products Limited plant in Cambridge, Ontario, Canada,
manufactures a variety of snack food items, including potato chips, corn
and tortilla chips, cheese sticks, pretzels, popcorn and novelty sugar
candy item called "poprocks". Potato chip production is by far the largest
volume operation at the plant and is also the largest source of process
wastewater generated at the plant. With this in mind, this paper will
highlight those aspects of an investigation into the wastewater discharges
relevant to Hostess potato chip production, with minimal reference to
wastewater generated by the other production processes.
Wastewaters from the Hostess plant are treated at the Preston treat-
ment plant - one of three municipal sewage treatment plants serving the
city of Cambridge. The treatment plant is of the conventional activated
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sludge type designed to treat 16,850 cubic metres per day (4.45 x 106 U.S.
gallons per day) of domestic wastes. Average daily wastewater flow to the
plant is about half of this figure.
While Hostess' process wastewaters amounted to about 20 percent of the
total hydraulic loading on the treatment plant, they made up over 75 percent
of the contaminant loading prior to implementation of the recommendations
that evolved from.the investigation.
In recent years, the treatment plant has experienced operating problems,
some of which were allegedly attributable to Hostess' wastes. These problems
eventually reached crisis proportions as numerous odour complaints were
registered by residents living near the treatment plant coincident with
severe upset conditions in the sewage treatment process.
Subsequent to this, the investigation and remedial program reported
herein was launched, ^his paper reviews the major findings and recommenda-
tions of that program.
INVESTIGATION AT POTATO PROCESSING PLANT
The Potato Processing Operation
A sketch of a typical potato processing line at Hostess as it appeared
before this investigation is presented in Figure 1.
From the storage bins, the raw potatoes are loaded into a surge hopper,
following which, they enter a rod washer where dirt is washed from their
outer skins. After washing, the potatoes are peeled in an abrasive peeler
and pass over an inspection table where below-specification potatoes are
manually culled for disposal elsewhere.
The peeled potatoes are directed to a fryer line feed hopper located
at the front each line. This hopper provides a buffer capacity to absorb
surges due to irregularities in either the potato peeling lines or the
potato chip frying line. This feed hopper discharges to a slicer which
slices the peeled raw potatoes into thin wafers. The sliced potatoes enter
a washer/blancher unit in which they are washed and sometimes blanched.
Following the washing/blanching step, the slices enter the fryer where they
are cooked in hot vegetable oil. Upon exiting the fryer, they are given
final inspection; the desired seasoning added, and they are packaged for
shipment.
For every pound of potato chips produced, approximately four pounds
of raw potatoes are utilized. The large discrepancy between the quantity
of raw potatoes and the quantity of final product is due mainly to the
evaporation of a portion of the moisture content of the potato slices
during frying. The peeling, slicing, washing/blanching, and off-specifica-
tion material losses account for the balance of the discrepancy.
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While potato chip production fluctuates seasonally according to market
demand, it is generally a two-shift operation, five days per week. The
fryers are drained and cleaned with a hot caustic solution during the third
shift.
Wastewater Sources
In Figure 1, it is seen that the major water-using components in the
production line are the washer, the peeler, the slicer, the washer/blancher
and the fryer exhaust gas scrubber. To reduce purchased water consumption,
the slicer water and scrubber blowdown are discharged to the washer/
blancher units.
There are three continuous-flow sources of wastewater which are dis-
charged to the plant drains - the washer effluent, the peeler effluent,
and the washer/blancher overflow. The washer effluent contains mainly
grit and sil~t washed from the outside of the raw potatoes. The peeler dis-
charge contains the peelings and some starch granules released from be-
neath the skin of the potatoes during the peeling operation. The washer/
blancher overflow contains whatever oil that entered with the scrubber
blowdown and has a high starch content due to the potato starch released
during the slicing and washing operation.
An intermittent effluent source, indicated by the dotted line in
Figure 1, is the caustic boilout from the fryer. This is a hot and highly
alkaline stream consisting of some free caustic and saponified cooking oils.
In-Plant Wastewater Survey
A sampling and analytical program for each contaminated effluent source
in the Hostess plant was performed. Composite samples were collected
during the operation of each production line and a typical total daily
process wastewater loading of about 4,540 kilograms per day (10,000 pounds
per day) each of BOD5 and Suspended Solids (S.S.) was estimated. The total
wastewater flowrate was approximately 1,360 cubic metres per day (360,000
U.S. gallons per day). The contaminant breakdown for the various "wet
processing" product lines was as follows:
Product Line BOD^ Contribution S. S. Contribution
Potatoes 70% 83%
Corn 15% 17%
Sugar 15% Nil
Pretzels Nil Nil
100% 100%
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As indicated above, potato chip production was by far the largest
contributor to the total effluent loadings.
During the sampling survey, it was found that the unit effluent load-
ings were approximately 14.5 and 16 kilograms of 8005 and Suspended Solids
respectively per tonne of raw potatoes processed (29 and 32 Ibs/ton). These
loadings are within the range of normally expected effluent loadings from
potato processing operations as reported in the technical literature (5)
(10).
Potato Slicing and Washing/Blanching Discharges
Concern had been expressed by the Regulatory Authorities that "emulsi-
fied oil" contained in the fryer exhaust scrubber blowdown was the cause
of many of the problems experienced at the municipal sewage treatment plant.
The scrubber blowdown stream is normally directed to the washer/blancher
where its heat content- provides hot-water makeup and its oil content assists
in controlling excessive foaming in these processing units. The authorities
were of the opinion that the Oils and Grease content of the scrubber blow-
down (which varies between about 50 and 200 mg/1) was interfering with the
settling performance of the primary clarifiers at the treatment plant.
Therefore, it was decided to conduct a definitive study of the effects of
the scrubber blowdown on the characteristics of the washer/blancher dis-
charge. At the same time, the effects of blanching on the characteristics
of the wastewater were also evaluated. These assessments were done on a
full-scale basis using the potato chip fryer lines at the Hostess plant.
The results are summarized in Tables 1 and 2 for two separate sampling
surveys. From these two Tables, it is seen that diversion of the scrubber
blowdown- away from the washer/blancher units had no significant effect
on the settleability characteristics of the washer/blancher overflow
stream.
However, blanching of the potato slices had marked effect on washer/
blancher effluent quality. When the potato slices were not blanched, the
washer/blancher overflow stream still had a high degree of contamination
but substantially more of it was settleable by gravity sedimentation than
if the potato slices were blanched. It is evident that the potato starch
released during the washing operation settles quite well as long as it
is not cooked by operating the washer/blancher unit at blanching
temperatures.
The above data indicate that the settleability of the potato pro-
cessing wastewater would be substantially greater if the potato slices
were washed and blanched sequentially in two separate processing units
rather than the Hostess practice of combined washing and blanching in a
single unit. The Suspended Solids (mostly potato starch particles) re-
leased from the potato slices during the slicing and washing only steps
would be discharged to the plant drains in the washer overflow, would
settle readily in a clarifier.
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Table 3 quantifies the benefits to be gained in altering the settle-
ability characteristics of the potato chip washer/blancher overflow water by
separation of the washing and blanching functions into two units. The data
reported in Table 3 x^ere estimated from the results of a third intensive
sampling survey in combination with data on washer/blancher overflow rates
and potato chip production rates. The data indicate that less total BOD. is
discharged to the plant drains if the washing and blanching functions are
separated than if they are combined. Furthermore, approximately half of this
BOD is settleable, whereas less than 20 percent is settleable if the washing
and blanching functions are combined into one processing unit. For Suspended
Solids, it is seen that about double the amount of Suspended Solids is gener-
ated by separating the washing and blanching functions. However, the charac-
teristics of the solids so generated are such that over 85 percent of them
are settleable, whereas only about 30 percent of the Suspended Solids gener-
ated during combined washing/blanching are settleable.
Effects of Chilling of Samples
Previous work done elsewhere by Hostess' parent company, General Foods
Corporation, as well as the early sampling results of this investigation
indicated that chilling of the samples had a marked effect on the Suspended
Solids levels measured at the laboratory according to Standard Methods (12).
Table 4 summarizes the effects of preserving the potato processing wastewater
samples by means of chilling prior to laboratory analysis. After collection,
all samples (chilled or not chilled) were held overnight prior to analysis.
In Table 4 it is seen that there is little effect (approximately 10
percent or less) on the BOD_ values of the washer/blancher samples and
blancher only samples. The "chilled" BOD of the prewasher samples averaged
about 30 percent less than the "not chilled" BOD of the same samples. As
heating during blanching will have some sterilizing effect, it is reasonable
to expect that the microbial populations in the pre-washer samples would be
far greater than those of either the blancher samples or the washer/blancher
samples. It is hypothesized, therefore, that the difference in BOD values
between the "chilled" and the "not chilled" prewasher samples is due to
anaerobic bacterial activity causing a solubilization of a portion of the
starch in the "not chilled" samples with a resulting higher BOD .
It is evident from Table 4 that there is a marked increase in Suspended
Solids caused by chilling of the washer/blancher samples. It is hypothe-
sized that this is due to a coagulation of a portion of the colloidal cooked
starch content of the "chilled" sample and that these coagulated solids are
then retained on the filter paper during the Suspended Solids test. Con-
versely, if the sample were "not chilled", the collodial solids would not
coagulate and would pass through the filter paper.
The "chilled" prewasher samples had a Suspended Solids level about 11
percent higher than the "not chilled" prewasher samples. It is hypothesized
that a portion of the uncooked starch granules in the "not chilled" pre-
washer samples was solubilized by anaerobic activity as mentioned earlier
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thereby resulting in a lower Suspended Solids level and a higher BOD5 level
than in the "chilled" prewasher samples.
The "chilled" blancher samples exhibited a Suspended Solids level about
20 percent higher than the "not chilled" blancher samples. This is likely
due to the coagulation of a portion of the colloidal cooked starch content
of the samples upon chilling as discussed above.
Table 4 indicates that the BOD^ level of potato processing wastewater
samples will increase upon standing if "not chilled". Table 4 also indi-
cates that "chilling" of the samples will cause an erroneously high Suspended
Solids level. Therefore, it is also important to note the advantage of
split sampling - "chilling" a portion of the effluent sample for BOD. analy-
sis and "not chilling" a portion of the sample for Suspended Solids analysis.
Furthermore, it is also important that the samples be analyzed as soon as
possible after collection.
Caustic Boil-Out Treatment
On the night shift each week-night, two potato chip fryers are cleaned
using a hot caustic solution. The resulting alkaline discharge to the sewer
is termed the "caustic boil-out". It is discharged over a relatively short
period of time (i.e. the time it takes to pump out the fryer) and therefore
constitutes a slug discharge from the plant occurring during the early morn-
ing hours.
Over ten different samples of caustic boil-out were evaluated and in
general, no two samples exhibited identical characteristics. Some of the
variations noted were as follows:
• Some separated into layers on standing for less than a day; others
did not separate at all even after standing for a month.
• Some formed a thick and relatively hard congealed layer on top; others
formed only a soft layer.
• Some formed a foamy layer on top; others did not.
• Some samples turned completely into a gel after standing for two to
three days; others did not.
In addition to the above, BOD5 determinations on the caustic boil-out
were very high and varied from about 10,000 mg/1 to over 60,000 mg/1. There
was also some evidence of a toxic inhibition caused by some constituent of
the caustic boil-out as higher BOD values were observed with larger dilu-
tions in the BOD- test. This toxicity is likely due to the soap content of
the caustic boil-out created as a result of a saponification reaction between
the hot caustic solution and any residual cooking oil it contacts while
circulating through the fryer. Aside from any congealed greasy substance
that might have formed, all samples showed very little evidence of Suspended
Solids contamination.
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As the caustic boil-out is a very strong waste and is discharged as a
slug, it was suspected as one possible cause of the upset conditions at the
municipal treatment plant. Therefore, it was recommended that it be segre-
gated from the other Hostess wastewaters for separate treatment.
Laboratory bench-scale studies on several samples showed that physical-
chemical treatment using a combination of lime and/or calcium chloride and/
or sulphuric acid could break emulsified oils and precipitate soluble soaps
from solution. The precipitation was filterable and a clear filtrate
resulted.
Due to the variations in the characteristics among the several samples
tested, the full-scale caustic boil-out treatment system was designed to
include the following processing steps:
• Retention tanks of sufficient capacity to hold at least one day's
production of caustic boil-out for one week to allow it to cool and
to permit separation and skimming of congealed material.
« Chemical addition, mixing, and decanting facilities on the holding
tanks to allow precipitation of the soluble soaps by lime or other
suitable chemical.
• A plate-and-frame filter press to filter the precipitated materials
and generate a filter cake for landfill disposal, and to pass the
filtrate to the plant drains over an extended period of time rather
than in one slug.
Table 5 shows that the full-scale caustic boil-out treatment system is
capable of better than 97 percent BOD5 removal and 99 percent Oils and
Grease removal. Chemical requirements are approximately 3.3 kilograms of
Calcium Chloride and 1.7 kilograms of Hydrated Lime per cubic metre of
caustic boil-out treated (27.5 and 14.2 pounds per 1000 U.S. gallons respec-
tively) . This is equivalent to an approximate chemical cost of $100 per
tonne of caustic boil-out treated ($3.80 per 1000 U.S. gallons).
Hostess' Pre-Treatment System
When the chronic upset conditions at the municipal treatment plant
reached crisis proportions, a number of interim measures were instituted
by Hostess in an attempt to alleviate the problem. One such measure was the
installation of a modified truck trailer body to act as a wastewater
settling basin at the Hostess plant to reduce effluent loadings to the
municipal sewer system.
Subsequently, it was found that this settling basin was removing about
900 kilograms per day (2000 pounds per day) of Suspended Solids from the
plant effluent. As it was relatively economical to install and operate, it
was decided to upgrade the truck settling basin concept into a permanent
pre-treatment system as part of the investigative and remedial program
described in this paper.
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Accordingly, a number of recommendations were made to improve the pre-
treatment system and, at present, the system incorporates the following
steps as schematically illustrated in Figure 2:
• All process wastewaters except the caustic boil-out are directed to
an in-plant pumping station. The pumping station consists of a
large sump and two self-priming pumps. A float switch activiting a
high level alarm is located in the sump to warn of pump failure and
an impending overflow discharge to the municipal sewer system.
• The wastewater is pumped to two Hydrasieve screening units having
screen openings of 1 millimetre (0.04 inches). Solids coarser
than this (mainly peels, etc.) are separated from the main stream
and are discharged down a chute into tote bins for ultimate disposal
to a feedlot operation.
• After screening, the wastewater passes through two settling basins
operating in parallel, which together provide a theoretical reten-
tion time of about 40 minutes. Heavy solids separate by gravity
to the bottom of the basins. In addition, a pair of baffles in
each basin retains any floating oils and greases. Multiple weir
plates along the width of each end of the settling basins provide
adequate inflow and overflow distribution patterns.
• The overflow from the settling basins passes through a Parshall
Flume to monitor the flowrate. A flow-proportional automatic
sampling device is also provided to sample the discharge from the
settling basins.
When a basin fills with settled material, it is hauled away and dumped
at a feedlot operation. A third truck trailer body is available to replace
the trailer being dumped. Each basin is dumped on alternate days, usually
early in the morning before start-up of the first shift.
INVESTIGATIONS AT MUNICIPAL TREATMENT PLANT
Description of Preston Treatment Plant
A schematic diagram illustrating the wastewater sources to, and the
various processing operations of the Preston treatment plant is presented
in Figure 3. The nominal hydraulic design capacity of the plant is 16,850
cubic metres per day (4.45 x 10^ U.S. gpd). The nominal design BOD^ and
Suspended Solids capacity is 7940 kilograms per day each (17,500 pounds per
day each). It is designed and built as a conventional activiated sludge
plant for the treatment of municipal wastes.
Wastewater arrives at the plant by means of four gravity sewers. Each
sewer transports domestic waste; however the Bishop Street sewer also
conveys the major portion of the industrial waste loadings on the Preston
plant. It is worth noting that wastewater from the large Dover Street
Pumping Station is pumped directly to the plant through about 1200 metres
(4000 feet) of 406 millimetre (16 inch) forcemain followed by 460 metres
(1500 feet) of gravity sewer with no lateral connections.
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The primary treatment system at the Preston plant consists of trash
racks, grit removal, shredding and gravity sedimentation. Grit removal is
accomplished in a mechanically-raked "square" detritor and a barminutor
serves to shred the larger particles in the wastewater stream. Following
shredding, the wastewater enters primary clarifiers. There are four
primary clarifiers each 15.2 metres (50 feet) in diameter.
The primary effluent enters the aeration 'tanks where dissolved oxygen
is supplied to the micro-organisms by a mechanical aeration system. The
Preston plant has two aeration tanks in parallel. Each tank has a aeration
energy input of 93.3 kilowatts (125 HP) provided by five surface mechanical
aerators.
An iron solution is metered into the front end of the aeration tanks
to precipitate soluble phosphorus from the wastewater stream.
The aeration tanks discharge to four secondary clarifiers each 15.2
metres (50 feet) in diameter. Excess activated sludge flow is "wasted" to
the solids handling system via a splitter box to the primary clarifiers.
The raw sludge withdrawn from the bottom of the primary clarifiers is
pumped to the sludge digesters. The sludge digestion system consists of
two tanks, each 15.2 metres (50 feet) in diameter by 11.6 metres (38 feet)
liquid depth providing a nominal retention volume of 4520 cubic metres
(159,600 cubic feet). The primary digester is heated to 35°C (950F).
Digester gas is generated as a by-product of the digestion process and
is used in a heating system to heat the digester tank contents. Excess
digester gas is flared to atmosphere.
Historical Data
Plant operating records over a five-year period prior to the crisis
upset conditions were examined. The data indicated that the plant was
operating at about half of stated design capacity for both 'ROD^ and
Suspended Solids as well as flow.
Despite this, when the severe upset conditions occurred over a three -
month summer period, there was no Suspended Solids removal and very little
BOD^ removal in the primary clarifiers. Depending upon the severity of
the situation at any time, the secondary section of the plant would be
overloaded as well. These upset conditions coincided with heavy scum
accumulations on the primary clarifiers and numberous odour complaints from
nearby residents.
Preston Treatment Plant Loadings
In order to confirm the loading data in the plant's operating records
and to establish the diurnal variations in wastewater contaminant loadings,
a 24-hour sampling program was implemented at the Preston plant.
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The daily BOD5 and Suspended Solids loadings were measured to be 6620
and 5810 kilograms per day respectively (14,600 and 12,800 pounds per day
respectively). These are considerably greater than the average daily BOD5
and Suspended Solids loadings of about 4260 and 3450 kilograms per day
respectively (9,400 and 7,800 pounds per day respectively) indicated on the
daily plant record sheets for that period.
While it is possible that the loadings may have been unusually higher
than average during the sampling survey, it is more likely that the daily
plant records underestimated the actual situation. The plant data were
based on 8-hour composite sampling of rax-7 wastewater entering the plant
during the day shift only. As Hostess potato processing operations commence
at 0700 hours and there is a 3-hour time of travel in the Bishop Street
sewer, the first portion of the 3-hour composite sample would be mostly the.
relatively "weak" domestic wastes. Hostess potato processing, which
represents about 70 to 80 percent of the total Hostess loading, continues
for two shifts until -2300 hours. Clean-up operations on the potato process-
ing lines often occur during the latter part of the second shift. There-
fore 8-hour composite sampling of raw wastes at the Preston plant would be
non-representative of the actual situation.
Table 6 summarizes the hydraulic, organic and solids loadings on the
Preston treatment plant. It is interesting to note that, while the Hostess
discharges represented less than 20 percent of the hydraulic load on the
Preston plant, they accounted for in excess of 75 percent of the BOD^ and
Suspended Solids loadings.
On examining the diurnal variations, it appeared that high BOD5 and
Suspended Solids concentrations occurred in the raw wastewater in the period
between 0300 and 0500 hours. This corresponded to the time that the caustic
boil-out discharges were expected to reach the plant. This was verified by
visual inspection of these samples (they appeared milky-white in colour) and
the fact that they had elevated pH level.
In view of the above, it was recommended that an automatic sampling
device be installed permanently at the Preston treatment plant to give a
more accurate picture of the plant loadings. The sampler should have the
capabilities of collecting discrete as well as composite samples around-
the-clock.
Hydraulic Surging
Inspection of the Preston plant's flowmeter charts showed that the
plant was subjected to severe hydraulic surgings. The plant operating per-
sonnel confirmed this,but the specific cause of the surges was not known for
certain. The flowmeter charts indicated a surging pattern as follows:
A hydraulic surge to a flowrate often in excess of 20440 cubic
metres per day (5.4 million Imperial gallons per day) occurring
approximately each hour during the daytime and every two to three
hours at night. This surge started abruptly and ended abruptly
and had a duration of about 5 minutes.
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After reviewing a drawing of the city's sewage collection system and
making a visual inspection of the flow patterns in the various sewer man-
holes°leading to the plant, it was determined that the surge was due to the
on-off operation of the Dover Street Pumping Station. Inspection of the
pumping station indicated that there was considerable excess capacity built
into the station for future expansion of the municipality. The pumps were
far larger than required for current flows. While this would be useful in
the long term, the nomina] hydraulic design cap'acity of the present primary
treatment system was exceeded by about 10 to 15 percent when this pumping
station operated. Such an excess usually would not result in serious 'upset
problems; however, with the unique combination of factors that occurred at
the Preston plant, the surging served to aggravate an already potentially
troublesome situation. The various factors were:
• The occurence of Oils and Grease accummulations from a possible spill
at Hostess and/or caustic boil-out gel accummulations on the primary
clarifiers.
• The existence of readily biodegradeable but poorly-settling
gelatinized starch waste resulting from the combined washing/
blanching operations on the Hostess potato chip lines.
• The wastewater entering the plant during these surges had different
characteristics than that entering the plant at most other times
with the result that undesirable density currents would be
created leading to unstable flow patterns in the primary clarifiers,
• The average hydraulic loading on the Preston treatment plant is
about half of the nominal design capicity. Therefore surges due
to the Dover Street Pumping Station resulted in an instantaneous
peaking factor of about 3:1. Such conditions are unacceptable for
good primary clarifier performance which is dependent upon quiescent
settling conditions.
It was recommended that the pumps in the Dover Street Pumping Station
be changed to pump at a lower rate over a longer period of time during each
pumping cycle.
Organic Loading on Preston Treatment Plant Secondary Section
The efficient performance of any biological waste treatment system
depends upon an optimal combination of several design and operating
variables, all of which are inter-related to some degree in a complex
physical, chemical and biochemical system. In order to simplify the system,
several parameters are used as a guide to assist the process engineer in
designing the treatment plant, and the operator in controlling the process
once it is in operation.
One of these is called the "Food-to-Micro-organism Ratio " (F:M) and
is a measure of the organic strength of the wastewater (expressed daily
mass loading of BOD5) in relation to the amount of activated sludge
microbial mass that is available in the secondary treatment system (express-
ed as mass of Volatile Suspended Solids in the aeration tanks) to consume
it.
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During the sampling period, the F:M ration was calculated to be 0.68
days"-'-. This figure is somewhat high and is outside of the traditional
"acceptable" F:M range of 0.2 to 0.5 days"-'- for a conventional activated
sludge plant. For this particular plant treating this particular wastewater
having an unusually high carbohydrate content, the recommended operating
range is as follows:
F:M ' MLSS
0.24 days'1 4000 mg/1
0.32 days'1 3000 mg/1
The above assumes an 85 percent volatile content in the Mixed Liquor
Suspended Solids.
The operating staff at the plant have experienced problems in main-
taining a high biomass concentration in the aeration tanks, and thereby
a high F:M ratio results. This is due to poor settleability of the biomass
and could be caused by many factors. Some possibilities are as follows:
» Insufficient nutrient concentrations in the primary effluent for
the promotion of a healthy activated sludge biomass (see below).
This is often the case with potato processing wastewater.
• Insufficient aeration retention time for the micro-organisms to
digest the high carbohydrate content of this particular wastewater
and form a well-flocculated,rapidly-settleable biomass.
t Toxicity of the saponified oils discharged in the Hostess caustic
boil-out discharges.
» Toxicity of heavy metals discharged from other industrial sources.
In the past, several process upsets in the secondary section of
the plant have been attributed to heavy metal discharges from other
industries
Nutrient Availability in Preston Treatment Plant Secondary Section
Nitrogen and Phosphorus nutrients must be present in the primary
effluent in sufficient amount and in an appropriate chemical form such
that the healthy growth of the biomass at the expense of the organic con-
taminants in the wastewater is not impaired by a nutrient-limiting con-
dition. Typically a BC^iN:? ratio of 100:5:1 is considered acceptable
for activated sludge treatment.
Nitrogen and Phosphorus determinations were made on composite samples
of primary effluent collected during the sampling survey. It was found that
there was sufficient Nitrogen in the primary effluent; however the
adequacy of the Phosphorus content was questionable. This marginal situa-
tion was further aggravated by the addition of Phosphorus-precipitating
chemicals at the head end of the aeration tanks causing insoluble phosphate
compounds to form which rendered the Phosphorus unavailable to the biomass.
In support of this concept, an examination of historical plant data on
the settleability of the Mixed Liquor Suspended Solids was made. The
340
-------
interval covered included both before and after the changeover from Ferric
Chloride addition at the outlet of the aeration tanks to a Ferrous/Ferric
solution addition at the entrance of the aeration tanks. The average
monthly data are presented in Table 7.
While it is recognized that analysis of the historical data in this
fashion overlooks many other factors occurring simultaneously, nevertheless
an obvious trend is evident - that the settleability of the Mixed Liquor
deteriorated after the replacement of Ferric salts by Ferrous/Ferric
salts and the change in dosing point of the chemical.
Further evidence of a Phosphorus-limiting conditions was found by
measuring the Phosphorus content of the Mixed Liquor biomass in the second-
ary treatment section of the plant. The average Total Phosphorus content
of the Mixed Liquor Suspended Solids in the aeration tanks during the
sampling survey was 5.75 mg/1. The average Mixed Liquor Volatile Suspended
Solids concentration-was 1420 mg/1. Therefore, the fraction of Phosphorus
in the MLVSS is 0.0041. A typical literature value (9) for activated sludge
is 0.0116. Therefore, the Preston plant's Mixed Liquor appears to be
Phosphorus deficient.
It was recommended, therefore, that a return to Ferric salts for pre-
cipitation of Phosphorus be made and that the dosing point be changed back
to the aeration tank overflow in order to minimize the possibility of a
limiting Phosphorus nutrient condition developing in the secondary section
of the treatment plant.
CONCLUSIONS AND RECOMMENDATIONS
Regarding the Potato Chip Processing Plant
The following conclusions and recommendations are made relevant to the
potato chip processing plant:
(1) If blanching of the potato chip is necessary, then a pre-washing step
prior to blanching will improve substantially the settleability of the
potato processing wastewaters.
(2) Conclusion (1) above has important implications for either the design
or the operation of treatment facilities for potato processing waste.
A primary treatment system will be much more effective on treating
wastewater from separate washing and blanching facilities than from a
combined washing/blanching unit. Furthermore, if secondary biological
treatment is required, it can be a smaller and less expensive system
if the washing and blanching functions are separated than if they are
combined. If the washing and blanching functions are combined, there
would be a much higher BOD5 load pass through the primary system and
into the secondary system.
(3) Either for determining the loading on a treatment system for potato
processing wastes, or for estimating surcharge penalties for discharge
of the wastes to a municipal sewer system, it is important to collect
split samples of the wastewater stream. One sample should be chilled
immediately for BOD5 analysis, and the other should be maintained at
341
-------
room temperature for Suspended Solids analysis. Furthermore, the
samples should be analysed as soon after the sampling as possible
to prevent microbial activity from causing a deterioration of the
sample.
(4) The caustic boil-out discharge resulting from fryer cleaning operations
represents a "slug" discharge of a very high strength waste containing
appreciable quantities of emulsified and saponified cooking oils. This
discharge could have a significant negative impact on the operation
of smaller size treatment facilities where the dilution afforded by
wastewaters from other sources is not large. A treatment process
consisting of retention tanks to permit separation and skimming of
congealed materials; chemical addition, blending, and decanting
facilities for precipitation of soluble soaps; and a filter press
to filter the precipitated materials before discharging the filtrate
to the sewer, will substantially reduce the strength of the caustic
boil-out waste stream.
(5) A "quick and dirty" but economically effective wastewater pre-treatment
system has been designed and installed by Hostess for all process
wastewaters excluding the caustic boil-out. The system consists of
screening followed by gravity separation of settleable and floatable
materials into appropriately modified dumptruck trailers. Each
trailer is taken off-line on alternate days and the accumulated solids
therein are hauled to a feedlot and dumped.
Regarding the Municipal Treatment Plant
Based upon the results of this investigation, the following points
should be given consideration in situations where a large wet processing
industry located in a relatively small community is discharging wastewater
to the sewer system for subsequent treatment at the municipality's
sewage treatment plant:
(1) Whereas the treatment plant may only be staffed on one shift and the
industry may be in production over two or more shifts each day,
an automated 24-hour sampling device should be used to collect re-
sentative samples of the combined wastewater for an accurate deter-
mination of the loadings on the treatment plant.
(2) All reasonable measures should be taken to avoid situations which by
themselves may not be of much significance (e.g. hydraulic surging),
but when in combination with other circumstances, may serve to aggra-
vate a chronic but marginally tolerable problem to crisis proportions.
(3) The nutrient balance in the combined wastewater must be adequate for
effective biological treatment.
(4) Proper operating conditions (as defined by the F:M ratio or other
acceptable operating parameter) consistent with effective biodegrada-
tion of the particular wastewater stream undergoing treatment should
be maintained in the biological treatment section.
(5) When a major portion of the loading to the treatment plant originates
from an industrial source(s), the design of the treatment plant must
accommodate the treatability characteristics of the industrial waste(s)
involved.
342
-------
(6) And last but not least, an effective mechanism of communication should
be established between the responsible industrial staff, the treatment
plant operating staff, municipal officials, and the Regulatory
Authorities. If this is done, a confrontation atmosphere can be
avoided whenever problems arise, and all concerned can set about re-
solving the difficulties.
OUTCOME
With the implementation of the following measures at the Hostess plant:
• Separation of washing and blanching to alter the settleability
characteristics of the potato processing wastewater,
• Upgrading of Hostess' pre-treatment facilities to improve the
degree of treatment given to the wastes before discharge to the
municipal sewer system,
• Implementation of a caustic boil-out treatment system,
• Improved employee awareness and in-plant housekeeping to avoid
accidental spills, unnecessary dumping, etc.
a reduction in contaminant loadings discharged to the municipal sewer system
of about 50 percent has been effected. In addition to resolving the pro-
cess upset and odour problems at the Preston treatment plant, there has
been a 37 percent reduction in Hostess' sewer surcharge payments to the
municipality despite an 18 percent.increase in the sewer surcharge rate.
ACKNOWLEDGEMENT S
The co-operation and assistance of representatives of the f.ollowing
organizations during the conduct of the investigation are gratefully
appreciated:
• City of Cambridge
• Regional Municipality of Waterloo
• Ontario Ministry of Environment
• Hostess Food Products Limited
REFERENCES
(1) Atkins, P.F., and Sproul, 0.J., "Feasibility of Biological Treatment
of Potato Processing Wastes", Journal Water Pollution Control
Federation, 38, 1287 (1966).
(2) Cansfield, P.E., and Gallop, R.A., "Conservation, Reclamation and
Re-Use of Solids and Water in Potato Processing", A paper presented
at the 19th Annual Ontario Industrial Waste Conference, (1970).
(3) French, The R.T. Company, "Aerobic Secondary Treatment of Potato
Processing Wastes", NTIS Publication No. PB200623, December, 1970.
343
-------
(4) Grames, L.M., and Jueneman, R.W., "Primary Treatment of Potato Pro-
cessing Wastes with Byproduct Feed Recovery", Journal Water Pollution
Control Federation, 41, 1358 (1969).
(5) Guttormsen, K., and Carlson, D.A., "Current Practice in Potato Pro-
cessing Waste Treatment", NTIS Publication No. PB189232, October, 1969.
(6) Landine, R.C., and Dean, J.R., "Waste Treatment and Solids Recovery
System for a French Fried Potato Processing Plant", A paper presented
at the 19th Annual Ontario Industrial Waste Conference^ (1972).
(7) McKinney, R.E., Microbiology for Sanitary Engineers, McGraw-Hill, New
York, 1962.
(8) Metcalf & Eddy, Inc., Wastewater Engineering - Collection, Treatment,
Disposal, McGraw-Hill, New York, 1972.
a
(9) Rich, L.G., Unit Processes of Sanitary Engineering, Johy Wiley & Sons,
Inc., New York, 1963.
(10) Stephenson, J.P., and Guo, P.H.M., "State-of-the-Art Review of
Processes for Treatment and Reuse of Potato Wastes", Environmental
Protection Service, Environment Canada, Report No. EPS 3-WP-77-7,
March 1977.
(11) United States Environment Protection Agency, "Pollution Abatement in
the Fruit and Vegetable Industry", U.S. E.P.A. Publication No.
EPA-625/3-77-0007, July 1977.
(12) Water Pollution Control Federation, American Water Works Association,
American Public Health Association, Standard Methods for the Examina-
tion of Water and Wastewater, 14th Edition, 1976.
344
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TABLE 1
EFFECTS OF BLANCHING AND SCRUBBER DIVERSION
ON WASHER/BLANCHER OVERFLOW SETTLEABILITY
SAMPLING SURVEY NUMBER 1
Potato Chip
Fryer No.
1
2
3 (a.m)
3 (p.m.)
4
— ~
Blanching?
Yes
Yes
No
No
No
~
Scrubber
Discharge?
To
Blancher
Diverted
To
Blancher
Diverted
To
Blancher
Settleable
BOD5
Fraction
10%
13%
55%
65%
70%
Settleable
S.S.
Fraction
85%
86%
98%
99%
95%
Note difference in settleabilities between blanching (#1 and #2) and not
blanching (#3 and #4). Scrubber diversion away from the washer/blancher
units does not appear to have substantial impact on the settleability of
the washer/blancher overflow.
Average settleable BOD5 fraction with blanching = 11.5%
Average settleable BOD^ fraction without blanching = 63%
Average settleable S.S. fraction with blanching = 85.5%
Average settleable S.S. fraction without blanching = 97%
345
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TABLE 2
EFFECTS OF BLANCHING AND SCRUBBER DIVERSION
ON WASHER/BLANCHER OVERFLOW SETTLEABILITY
SAMPLING SURVEY NUMBER 2
Potato Chip
Fryer No.
1
2
3 (a.m.)
3 (p.m.)
4
Blanching?
Yes
Yes
No
No
No
Scrubber
Discharge?
To
Blancher
Diverted
To
Blancher
Diverted
To
Blancher
Settleable
- BOD5
- Fraction
17%
13%
42%
69%
60%
Settleable
S.S.
Fraction
72%
80%
95%
96%
96%
Yes
Diverted
81%
Note difference in settleabilities between blanching (#1, #2 and #5) and
not blanching (#3 and #4). Scrubber diversion away from the washer/
blancher units does not appear to have substantial impact on the settle-
ability of the washer/blancher overflow.
Average settleable BOD^ fraction with blanching = 12%
Average settleable BODr fraction without blanching = 57%
Average settleable S.S. fraction with blanching = 78%
Average settleable S. S. fraction without blanching = 96%
346
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TABLE 3
ESTIMATED EFFLUENT LOADINGS FOR
PflMRTNED AND SEPARATE WASHING AND BLANCHING
BOD, Loading (kg/tonne Product)
Sample After 30 Min.
As Is
Ideal Settling
S.S. Loading (kg/tonne Product)
Sample After 30 Min.
As Is Ideal Settling
45
19
38
10
13
25
Item
Combined
Washing/
Blanching
Separate
Washing &
Blanching
The BOD, values above indicate that there is considerably less BOD5 dis-
charged per unit of production both before and after ideal settling if the
washing and blanching functions are separated than if they are combined.
The Suspended Solids values above indicate that, although there is more
Suspended Solids generated per unit of production by separation of the
washing and blanching functions, there is considerably less Suspended
Solids discharged after ideal settling if the washing and blanching
functions are separated than if they are combined.
347
-------
TABLE 4
SUMMARY OF EFFECT ON CHILLING SAMPLES
ON MEASURED BODs & SUSPENDED SOLIDS ANALYSES
Item
Washer/Blancher
Samples
Prewasher
Samples
Blancher ,
Ratio of "Chilled" to "Not Chilled" Sample Analysis
Chilled
BOD5 Ratio .. ^rT":: , S.S. Ratio
-> Not Chilled
Mean
Ranee
0.89 0.81 to 1.01
0.68 0.46 to 0.83
0.93 0.60 to 1.15
Mean
Not Chilled
Range
2.63 2.07 to 2.91
1.11 0.76 to 1.30
1.50 1.01 to 1.89
TABLE 5
RESULTS OF FULL SCALE TREATMENT OF
CAUSTIC BOIL-OUT DISCHARGES
Item
Test No. 1
Test No. 2
BODs Conc'n (mg/1)
Oils & Grease Conc'n (mg/1)
Before
Treatment
59,800
26,400
After
Treatment
1,890
970
Before
Treatment
26,000
12,200
After
Treatment
22
348
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TABLE 6
SUMMARY OF LOADING CONDITIONS
ON THE PRESTON TREATMENT PLANT
From Plant Data
Probable* Situation
Item
Nominal
Design
Flow
(m3/day) 16850
BODr
(kg/day)
7940
S.S.
(kg/day) 7940
Avg.
Loading
7680
3970
4290
% ,of Stated
Design
46
50
54
Ayg.
Lpading
7680
5960
5960
% of Stated
Design
46
75
75
Assumes average Hostess discharges of approximately 4260 Ib/day each of
BOD- and S.S. (dependent upon production levels) plus sewered population of
18,300 each discharging 0.09 kg/day BOD5 and 0.09 kg/day S.S.
Table 7 SETTLEABILITY OF PRESTON TREATMENT PLANT MIXED LIQUOR
AS A FUNCTION OF PHOSPHORUS-PRECIPITATING CHEMICAL ADDITION
Year
1
2
Phosphorus-Precipitating Point of Settled MLSS Volume*
Chemical Used Chemical Addition After 30 Min. Settling
Ferric Sol'n
Ferric Sol'n
Aeration Output
Aeration Output
445 ml
380 ml
(Jan-April) Ferric Sol'n
Aeration Output
410 ml
(April-Dec) Ferrous/Ferric Sol'n Aeration Input
4 Ferrous/Ferric Sol'n Aeration Input
5 Ferrous/Ferric Sol'n Aeration Input
665 ml
730 ml
755 ml
* These figures represent annual average values recorded in the plant
performance records. Data covering those periods when washout of the
Mixed Liquor Suspended Solids (MLSS) occured were not included in these
averages. The washouts were often attributed to heavy metal contamina-
tion of the raw wastewater.
349
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CITY WATER
Vffr*er.~A "^
RAW POTATOES
V
WASHER
>
Fryer
Exhaust
Seasoning
Ad dil i ves
PA
C
K
A
G
N
G
V
Culls to
Fee dlot
PEELER eS3SSMa»affl»HSSSSSSS2B^(
A
INSPECTION
4
S L 1 C E R
T
W A S ! i E R /
Z L A N CHER
i
FRYER
^
INSPECTION
4
s F A c, O N 1 IV G
3KST3
"«"•-
Waslewoter
to drain
POTATO CHIPS
POTATO
C HIP
PRODUCTION
FIGURE i
350
-------
WASTEWATER SOURCE
CONTAMINANT CONTRIBUTION
POTATO PROCESSING 70 %
CORN PROCESSING 15 %
SUGAR PROCESSING 15 %
HYDRASIEVE
SCREEN 'A'
IN - PLANT SUMPS
AND PUMPING SYSTEM
screenings /u
to feedlot
HYDRASIEVE
SCREEN 'B'
STANDBY
TRUCK
TRAILER "
SETTLING
BASIN
r~
TRUCK
TRAILER
NO. 1
SETTLING
BASIN
««!WSB^>^paBT!l»U^«»!Bas»S^XJaia!aia!*
settled
solids "
^ to feedlot ^
4
METERING AND
SAMPLING SYSTEM
»va235ffla»353
TRUCK
TRAILER
NO. 2
SETTLING
BASIN
TO CITY SEWER
HOSTESS
PRE-TREATMENT
SYSTEM
FIGURE 2
351
-------
INDUSTRIAL AND
DOMESTIC WASTES
BISHOP ST.
SEWER
DOMESTIC
WASTES
DOMESTIC
WASTES
DOMESTIC
»KEM
Trash to
Landfill
Grit to
Landfill
Scum to
Landfill
Settled sludge
to Digesters
Return
Acii voted
Sludge
MONTROSE ST. BECK ST.
SEWER SEWER
DOVER ST.
PUMPHOUSE
SEWAGE
COLLECTION
SYSTEM
TRASH RACK-
GRIT REMOVAL
SH
R
E
D
D
1 N
G
V
PRIMARY CLARIFIERS
AERATION TANKS
SECONDARY CLARIFIERS
DISINFECTION
PRELIMINARY
TREATMENT
S>STEM
SECONDARY
TREATMENT
SYSTEM
TO GRAND RIVER
PRESTON SEWAGE
REATMEN
SYSTEM
FIGURE 3
352
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PB93-1U2372
JOINT TREATMENT DESIGN AND OPERATION PROBLEMS
WITH A FINE PAPER MANUFACTURING WASTEWATER
J. D. Lowry
Assistant Professor of Civil Engineering
451 Aubert Hall
Civil Engineering Department
University of Maine
Orono, ME. 04473
ABSTRACT
The paper describes the efforts of the author, who was retained as an
outside consultant, to evaluate and provide solutions to process problems en-
countered in a joint treatment facility located in Brewer, Maine. The 3.0
MGD facility receives wastewater from the city (10,000 population) and indus-
try (fine paper making), and has been plagued with operation problems since
its startup in 1976.
The objective of the paper is to discuss:
1) the technical aspects of the operation problems, with respect to
design inadequacies and process operation, 2) the technical solutions to the
problems, which involved a field research effort, and 3) the interactions
between the city, industry, design consultant, state government, and EPA,
with emphasis on how each influenced the implementation of the technical
solutions.
The work described in the paper is relevant to joint treatment design
and operation for two reasons. First, the Brewer, Maine facility is unique
from a technical standpoint because the problem industrial wastewater loading
is at a level that allowed some clear cause-effect relationships to be dis-
cerned. These included typical ones involving nitrogen and phosphorus, as
well as other wastewater nutritional problems of a more unusual nature. In-
vestigations led to some potentially meaningful data that may be applicable
to facilities experiencing problems with similar wastewaters. Secondly, the
Brewer facility is quite representative of the predicament small cities can
find themselves in when they accept the wastewater of a comparatively large
industry.
INTRODUCTION
For a variety of reasons, many municipal wastewater treatment
facilities throughout the country are not meeting their prescribed effluent
353
-------
discharge standards (1,2). Some of these plants have experienced difficul-
ties attributable to significant industrial wastewater loading and, in par-
ticular, joint treatment facilities are especially prone to problems caused
by industrial wastewaters. Proper process design and operation is always
critical to the successful performance of any treatment facility, but is
usually more difficult to achieve in joint treatment applications. This
paper describes the design and operation problems encountered by the author
at a joint treatment facility in Brewer, ME., and details the various solu-
tion measures that have been implemented by the city and industry.
The Brewer wastewater treatment plant is a typical secondary design em-
ploying the activated sludge'process. The process flow schematic is illus-
trated in Figure 1 and the basic design data are given in Table 1. The
facility was designed for the combined treatment of wastewater from the mu-
nicipality and Eastern Fine Paper Company. At the present time, the mill
contributes approximately 40% of the total average flow in the form of waste-
water generated from three paper machines that manufacture various grades and
colors of fine paper.
TABLE 1. BASIC DESIGN DATA
Design Flow
Combined 3.03 MGD
City 1.95 "
Mill 1.08 "
Present Flow
Combined 2.50 MGD
City 1.50 "
Mill 1.00 "
BODr Combined 265 mg/L
b 6700 Ib/d
SS Combined 376 mg/L
9500 Ib/d
Aeration Time, Design 7.2 hr
The activated sludge system can be operated with one or two aeration
basins in service, and with one or two sedimentation basins in either case.
If two aeration basins are used with two sedimentation basins, either com-
bined or separate return sludge systems can be utilized. If the return
sludge lines are kept separate, the operation becomes two parallel activated
sludge systems that receive a portion of the same combined wastewater flow.
This has been the mode of operation, with an intended 50:50 split of waste-
water to each aeration basin-sedimentation tank combination. It is not
possible to treat the Brewer and Eastern wastewaters separately due to the
common aeration influent feed channel.
354
-------
FIGURE I
Ul
Ui
PROCESS FLOW PATH
"*-Or
MUNICIPAL AND INDUSTRIAL
WASTEWATER FLOW
— — —•——— SLUDGE FLOW
-------
Poor process performance has plagued the treatment facility since its
startup in November of 1975. In general, the major problem has been related
to the predominance of filamentous bacteria in the activated sludge process.
Classic bulking sludge problems have resulted in massive losses of process
solids, unstable operation, and repeated violations of discharge standards.
Prior to the work described in this paper, a variety of measures taken to
eliminate the bulking sludge problem had been unsuccessful, making control of
the process extremely difficult and satisfactory operation impossible.
As a result of the continued poor performance of the treatment facility,
pressure by the regulatory agencies led the city and industry to employ the
auchor as a consultant. The ensuing evaluation, field work, and solution im-
plementation effort by all parties involved has resulted in significant de-
sign modifications to the facility and some interesting findings concerning
joint treatment of a fine paper mill wastewater.
PERFORMANCE EVALUATION
This section briefly summarizes the work conducted at the treatment
facility during the last 16 months. The objective during the period has been
to achieve a stable activated sludge process operation through the elimina-
tion of conditions which promote the predominance of filamentous microorga-
nisms in the MLSS. The work has progressed through an iterative process
involving: 1) evaluation, 2) solution implementation, and 3) re-evaluation,
to achieve the objective. The results can be separated into the four basic
phases described below. The complete information describing the study up to
and including Phase III is contained in an engineering report written for
the city (3).
Phase I
At the beginning of Phase I, the aeration process was dominated by three
species of filamentous bacteria and solids could not be maintained due to
severe bulking conditions present in the secondary clarifiers. In an attempt
to determine the environmental factors responsible for this condition, a pre-
liminary evaluation of past operation and performance was performed. The
results of that evaluation are summarized below:
1. Municipal Raw Wastewater - daily grab
a. Average BOD - 170 mg/L
b. Average SS - 112 mg/L
c. pH range - 6.4 to 9.2
2. Paper Mill Raw Wastewater - daily composite
a. BOD range - less than 200 to over 1300 mg/L
b. SS range - less than 200 to over 2500 mg/L
c. pH range - 4.3 to 9.4
356
-------
3. Primary Effluent - Combined
a. BOD- - 2 grab samples per month routine
- 21 composite (24 hr) samples
represented in Figure 2 indicated
reasonable loading based on very
limited data
- data in Figure 3 indicated effective
removal by primary system
b. SS - 16 grab analyses average-67 mg/L
c. pH - no routine analyses
d. Alkalinity - 1 grab per week ranged from
44 to 107 mg/L as CaCO
4. Aeration System
a. Nitrogen - not measured
b. Phosphorus - not measured
c. "pH - not measured
d. Dissolved Oxygen (D.O.) - measured once per day;
periods of low D.O. were indicated occasionally
but generally in excess of several mg/L.
5. Effluent - measured concentrations of N and P indicated
that insufficient levels existed in aeration
system.
6. General Process Performance
a. Brief periods of good operation (SVI 100) had
occurred in the past, generally corresponding
to periods of excess NH--N as evidenced by
nitrification.
b. Previous efforts to solve the operational problems
included chlorine addition, lime addition, nitrogen
and phosphorus addition, commercial bacteria addi-
tives, and polymer addition to the secondary clari-
fier. In general, these efforts had been unsuccessful
for a variety of reasons.
The preliminary evaluation of operations clearly indicated that several
fundamental requirements were not being satisfied at all times. The result
of this situation had been the predominance of filamentous microorganisms,
bulking sludge, and generally unstable operations. Since the data were
limited and incomplete, an intensive short-term analysis was conducted to
obtain more complete information with respect to key aeration system param-
eters. The pertinent results of the evaluation are detailed below:
1. Hydrogen Ion Activity - pH
The pH was monitored hourly for a three-day period on
the aeration system, primary effluent, mill wastewater and
city wastewater. The data did not indicate any significant
problems; however, aeration system pH was between 6.5 and
357
-------
DISTRIBUTION ANALYSIS-PRIMARY EFFLUENT BOD.
u>
Ln
00
400
o
CO
UJ
ID
-I
li.
L_
LJ
>-
a:
o:
o.
300
200
100
+ 197= MEAN
FIGURE 2.
I I L
I 5 10 20 3040506070 80 90 95
PROBABILITY OF BODg < VALUE, %
99
-------
WHITEWATER BOD- vs. PRIMARY EFFLUENT BOD
o o
U)
Ln
E
in
0
0
CD
2
LU
ID
_J
i .
u_
U_
UJ
>-
tr
<
^.
Ql
Q_
1200
1000
800
600
400
200
0
-
-
«
•
o
GO ©
O/H
Q a.
o° % o a
uo o
o o
i i i i i i i i i i i i i i i i i i
0 200 400 600 800 1000 1200 1400 1600 I8OO
FIGURE 3.
EASTERN WHITEWATER BOD,.,mg/l
-------
7.2 during most of the period. In general, it appeared that
increased alkalinity might be required in the future.
2. Nitrogen
Influent and aeration system ammonia and nitrate levels
were measured hourly during the three-day period. BOD and
organic nitrogen levels were measured for 3-hr composited
samples. The ammonia and BOD^ data are presented in Figure 4
and show the addition of 52 lb/d of supplemental NH -N which
was being added from drums at the time. As expected, the car-
bohydrate-dominated wastewater from the mill contributed only
a small amount of nitrogen. Based on the traditional ratio
of 20/1 for BOD^/N, it was clear that even with the supplemen-
tal nitrogen addition the combined wastewater was marginal in
terms of nutrient supply. Data on organic nitrogen indicated
that most was" lost in the primary system. Nitrate concentra-
tions were generally less than 1.0 mg/L.
Aeration system data indicated that all the influent
ammonia was being utilized during a significant portion of the
three-day period (10 hr), and this is shown graphically in
Figure 5. It is important to note that nitrate levels also
indicated utilization during the heavier loading periods. It
is important to note that J:he BOD loading (see Figure 4)
measured during the period was below the average design level
of 4690 lb/d (195 Ib/hr). Therefore, deficient nitrogen
levels were present during conditions of below average BOD;.
loading.
3. Phosphorus
Dissolved phosphate analyses were performed on 100 hourly
grab samples and the results are summarized in Table 2.
TABLE 2. DISSOLVED PHOSPHORUS RESULTS
(values in mg/L PO.-P)
Sample Analyses
Mill
City
Primary Effluent
Aeration Basin 1
Aeration Basin 2
20
32
31
8
9
Range
0.
0.
0.
0.
0.
0
2
0
1
3
- 0.
- 10
- 2.
- 2.
- 1.
3
.6
2
3
5
Average Comment
1
1
1
1
-
.9
.0
.0
.0
16 values = 0.0
very erratic
very erratic
erratic
erratic
360
-------
PROCESS EVALUATION - INFLUENT AMMONIA
15
14
13
12
II
10
9
8
7
6
5
4
3
2
PRIMARY EFFLUENT
AFTER
NH -N ADDITION
+ EASTERN •/ 'i
6 N
1/4
FIGURE 4.
180
160
140
120
100
80
TIME.days
-------
FIGURE 5
Co
c^
M
PROCESS EVALUATION -AMMONIA IN
AERATION BASIN No. I
1/4
1/7
TIME, days
-------
Based on an average BOD5 of 200 mg/L and the tradi-
tional BOD /P ratio of 100/1, a deficiency in dissolved
phosphorus was indicated. The average concentration
entering the aeration process was only 1.0 mg/L, or about
50% of that required. An explanation for the dissolved
phosphorus concentrations present in the aeration system
might be that BOD metabolism was limited by the deficiency
of nitrogen that existed. It should- also be noted that
the levels measured in the city wastewater were low com-
pared to the average for municipal facilities.
Based on the results of the evaluations conducted
during Phase I, it was recommended that bulk nitrogen
and phosphorus addition systems be installed as perma-
nent facilities at the treatment plant. An alkalinity
system was recommended as a possible future requirement,
to"be decided upon after the effects of adequate nitrogen
and phosphorus addition on process performance had been
determined.
Phase II
Phase II was the field implementation of the recommendations for correc-
tion of N and P deficiencies. Since the installation of permanent bulk chem-
ical storage facilities would require several months, the field trial pro-
ceeded using chemical feed pumps and 55-galIon barrels of aqua ammonia and
phosphoric acid. The N addition objective was to maintain a minimum of
5 mg/L of nitrogen as a combination of NH -N and NO -N in the aeration basin.
Later it was found that this residual had to be increased during certain
periods due to extremely erratic demands. The dissolved P objective was
2 mg/L in the aeration system. These excess concentrations were maintained
to ensure adequate nutrients at all times. D.O. concentrations were also
maintained at excess levels for the same reason. Since the addition of
excess N, P, and D.O. was expensive and more could be learned by using one
aeration system as a control, supplemental N was not added to aeration basin
No. 2 during the field study. Using this approach, two identical parallel
systems were used to study the nitrogen requirements of the combined waste-
water treatment.
The results of Phase II consisted of two separate periods of field
study: 1) initial operation during high spring infiltration/inflow and
2) later operation during normal city flow in the summer. Since the process
was in an upset condition going into the high flow period, it was difficult
to establish a stable operation until the flow subsided some weeks later.
However, some useful information was gathered in a three-week period prior
to the higher flow.
With the initial addition of excess N and P to aeration system No. 1,
immediate improvement occurred. The MLSS increased from startup conditions
of 200 mg/L to approximately 2000 mg/L in a one-week period, and the facility
was meeting discharge standards. An industrial loading event occurred at
that point and, in spite of excess N, P, and D.O. concentrations, a
363
-------
filamentous bacterial species became established in less than 12 hr. Subse-
quent short-term erratic loading from the mill caused further deterioration
in process stability and bulking conditions were severe by the end of the
third week. Due to additional erratic loading and infiltration/inflow events
the field trial was unsuccessful until the spring runoff subsided. What was
significant at this point was the near continuous data which was gathered on
aeration system loading. It became clear that additional evaluation and
monitoring of organic loading would be necessary.
During the second attempt at providing excess N and P concentrations
some meaningful data were collected on process performance. In general, an
excellent stable operation was achieved in aeration system No. 1 (with sup-
plemental N), and a less stable operation was attained in aeration system
No. 2. Effluent standards were met for more than one month and performance
was better than any that had occurred at the facility since its startup.
Figures 6 and 7 are a summary of process performance in terms of solids and
settleability. While the data indicate only slightly improved stability in
aeration system No. 1, actual field performance of aeration system No. 2 was
much less stable. Several times during the period from late June through
early August, system No. 2 was close to upset and had a significant amount of
filamentous bacteria present until the final days of July. In contrast,
system No. 1 was extremely stable for nearly one month and was much less sen-
sitive to erratic short-term loading from the mill.
The reason for the observed and measured performance differences between
the two aeration systems can be seen in the "nitrogen data illustrated in
Figures 8 and 9. In Figure 9 it is clear that without supplemental N, the
naturally occurring N level was marginally adequate most of July, with nitri-
fication being complete when excess NH -N was available. The one period in
July of complete deficiency (7/20) is also reflected in the SVI data of
Figure 7, and microscopic analysis indicated a slight increase in filamentous
bacteria that subsequently diminished during the next few days with a return
to an excess N environment. In contrast, the data of Figure 8 show the
relatively high levels of excess NH--N and complete nitrification during July
and through early August. An important point to note in both figures is the
extremely variable demands for N, which also were reflected in the oxygen
demand. The increase in organic loading and corresponding large decrease in
aeration system N caused rapid filamentous growth at the beginning of the
second week in August. Without nitrogen, aeration system No. 2 lost treat-
ment efficiency over a one-week period. With excess nitrogen the filamentous
growth in system No. 1 was more extensive and the differences between the two
parallel systems can be seen in the SVI and solids data of Figures 6 and 7.
By mid-August, treatment in system No. 2 was virtually non-existent and
system No. 1 was not meeting standards due to intermittent bulking conditions
in the secondary clarifiers.
The most important fact derived from the operation depicted by Figures 6
through 9 was that the smaller of the three species of filamentous bacteria
established in the MLSS under conditions of excess N, P; and D.O. Thus, it
became obvious that a re-evaluation of the operating conditions was required
to arrive at a solution which could be implemented to achieve the original
objective. Actually, this third phase of evaluation had already been started
364
-------
MLSS 8 SVI SYSTEM I, JUNE-AUGUST
FIGURE 6
5000-
MLSS
I 5 10 15 20 25 30 5" 10 15 20 25 30 5 10 15 20 25 30
JUN
JUL
AUG
1979
365
-------
MLSS aSVI SYSTEM 2, JUNE-AUGUST
FIGURE 7
i iI I i i ii I i i l iI i i i i Il ii il l i i i I i i•i I
I 5 10 15 20 25 30 5 10 15 20 25 30 5 10 15 20 25 30
I I I
JUN JUL AUG
1979
-------
at the end of June after preliminary data in the spring had indicated prob-
lems with the erratic loading from the paper mill.
Phase III
In an attempt to monitor the loading to the aeration system and estab-
lish the conditions which caused process problems to occur, the chemical
oxygen demand (COD) and suspended solids (SS) were monitored during late June
through July, and for a five-day period in mid-August. These data are shown
in Figures 10 and 11. Since it appeared that the problems of the treatment
facility had been solved by late July, the monitoring was discontinued only
a few days prior to the establishment of filamentous bacteria.
The COD data of Figure 10 do not indicate any clear explanation to the
return of process problems in early August, since the actual samples for the
onset of problems were not available. However, loading was generally higher
in late July.and in mid-August. It should be pointed out that the process
was designed for a BOD loading of 4690 Ib/d and that the approximate ratio
of BOD,./COD was 0.55; therefore, the process was not "overloaded" in terms of
the intended design criteria. As evidenced by the earlier N data, the load-
ing was actually slightly below normal during most of July.
The SS solids data shown in Figure 11 indicate much higher loading dur-
ing the period before and after process problems occurred; however, the pro-
cess was designed for an average SS loading of 3800 Ib/d. As with COD load-
ing, it appears that SS was below the design average during most of the peri-
od. In comparing the COD and SS data it is clear that there were days of
extremely high soluble COD loading; e.g. on 7/20, and this was suspected to
be caused by an increased starch content in the mill wastewater.
The data in Figures 10 and 11 were derived from 4-hr, average samples;
therefore, an approximation of the diurnal loading was available for analysis.
Since the true cause of the process problems was not clear from the daily
averages, a more detailed loading evaluation was necessary. This evaluation
consisted of comparing the diurnal loading patterns for days of excellent,
stable process operation and days prior to and after the process problems
returned. These comparisons are summarized in Figures 12 through 14. The
loading on July 4 shown in Figures 12 and 13 represent the approximate city
loading after primary treatment, since the mill was shut down for the holiday.
The differences in loading patterns for the days shown are apparent.
Also, the influence of the mill wastewater is clear by noting the low loading
on July 4. The period that appeared to initiate the process problems in
early August is indicated by the flow data for the mill shown in Figure 14.
As a comparison, a day from the period of excellent process operation is also
shown. The differences between the two flow records are due to the dumping
of process tanks at the mill, which is normal in the operation of the paper-
making process when machines are periodically shut down for a variety of
reasons. It is also important to note that these "dumps" were not violations
of the influent agreement the mill has with the city, or what was anticipated
by the design engineer. Average influent loading limits had been exceeded on
certain days during the period and this undoubtedly compounded the problem;
however, a thorough data analysis indicated that the short-term loading
367
-------
00
SIDE I-NITROGEN CONCENTRATIONS. JUNE-AUGUST
FIGURE g
11 20
JUNE
AUGUST
-------
SIDE 2-NITROGEN CONCENTRATIONS, JUNE-AUGUST
FIGURE 9
15 2O
AUGUST
-------
OJ
-~J
o
12-
II-
IO
9-
8-
* 6
•£
Q 5-
PRIMARY EFFLUENT COD-DAILY AVERAGE
FIGURE 10
GRAB
301
10
JUNE
15
JULY
2O
25
30
"' ' ' 5 ' " ' ib ' ' ' ' ib
AUGUST
-------
PRIMARY EFFLUENT SS - DAILY AVERAGE
FIGURE II
w 3-
to
2-
iT
T
~^5
JULY
1 B iF
AUGUST
~^zrii &
JUNE
2O
25
-------
PRIMARY EFFLUENT COD-DIURNAL VARIATION
FIGURE IZ
12
10-
..
1 8
CO
£ ?.
I
f\
\ 6
8 5-
o J
4
3
2
1
O
I2i
II
1 r
10
$ 8.
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1 • / -
1 ro '
L L ° e
] . — 1 (T)
—--[__] !— r^ o 5
7/16/79 ° ,
7/15/79 4-
3
j 1 y-' 1
7/4/79 i 2
1
0
8/14/79
1 —
r-i
1
n
i— ' L_
7/"^n/7o ' 7/-?.i /7n
1 / / OU/ /;? l/Oif IJ
1 1 1 1 1 1 1 1 1 1 1 f
12N
I2M
I2N
I2M
I2M
I2N
I2M
I2N
I2M
372
-------
PRIMARY EFFLUENT SS- DIURNAL VARIATION
FIGURE 13
7/25/79
6-
5-
>*
^ 4-
-O
10
Q
co 3-
2-
1-
0-
l<
6-
5-
o
\ 4-
"^
V)
7/12/79 2.
_J L—
7/4/79
1 — ' ' — ' — 1 '"
M' ' &T ' I2M1 ' liN' ' liM °|
iM1 ' i!
7/30/79
2N' ' ifeM' ' &N' ' ll
373
-------
3.0i
OJ
^J
-p-
CO
5
O
I2M
EASTERN FLOW-DIURNAL VARIATION
FIGURE 14
52.K»gal -J / , -87.5OOgo!
1ST
-------
variation was the real problem and this type of event could occur when the
average daily loading from the mill was near normal. In addition, on most
days of exceedingly high mill loading the primary system acted as an effec-
tive buffer to the aeration system. The problem was found to be related to
loading events in which the ratio of mill/city BOD was at a maximum, and
this could be caused by infrequent poor SS removal in the primary or a dis-
charge of soluble COD.
Aside from the problems with the growth of filamentous bacteria, the
erratic loading events caused obvious process problems related to nutrient
addition and D.O. control. Both were controlled manually, based on monitor-
ing data, and were subject to any variation which occurred in process loading.
To ensure adequate levels of N, P, and D.O., the uneconomical approach of
maintaining significant excesses was necessary. These considerations, along
with others relating to process stability, led to the conclusion that any
future solution approach would have to be directed at changing the wastewater
loading prior to -the aeration system.
The primary question with regard to the predominance of filamentous bac-
teria was why were they competitive during these particular loading events?
Extremely high city loading caused by the initial period of sewer flushing
during infiltration events did not stimulate their growth. In fact, these
periods usually were followed by an improved bacterial population. Based on
all the available data concerning the operational characteristics of the
activated sludge process, it was concluded that the susceptibility of the
process to the establishment of filamentous sludge was probably due to the
unbalanced nature of the wastewater. The mill wastewater is primarily carbo-
hydrate in nature, containing paper fiber, sizing starches, etc., which are
naturally low in nutritional value. It is believed that during periods of
high mill/city BOD loading these carbohydrates present a problem from the
standpoint of being nutritionally poor, and this condition results in a fila-
mentous -activated sludge. Data indicated that the ratio of mill/city BOD
was normally about 3.5/1, but increased to greater than 10/1 during the
short-term loading events.
Several basic solution approaches were considered, but only those which
would reduce the ratio of mill/city BOD loading to the aeration system and
attenuate the loading variations were regarded as reasonable permanent solu-
tions. They would result in a more nutritionally balanced wastewater by
increasing the impact of the well-balanced city wastewater relative to the
carbohydrate wastewater of the mill. Three steps were considered:
1) A reduction of mill loading,
2) An increase in city loading,
3) Both 1 and 2.
With respect to the magnitude of total load, methods 1 and 2 would have
been opposite in effect; i.e., 1 would have reduced the magnitude and 2 would
have caused an increase that would have overloaded the aeration system. The
net effect of method 3 depended on the magnitude of change in 1 and 2 that
could be achieved.
375
-------
Based on the considerations summarized above, recommendations were made
to provide a solution to the remaining problems. An effective spill control
system was recommended as the most desirable solution; however, for economic
reasons it was decided that the feasibility of polymer addition to the mill
wastewater should be investigated. With polymer addition data from prelimi-
nary experiments conducted previously by the industry, it appeared that this
would be a viable alternative, in conjunction with a by-pass of municipal
wastewater directly to the aeration process. A' design modification to the
plant piping system was required to accomplish the by-pass due to a problem
with the original by-pass design.
Phase IV
Additional laboratory work at the mill allowed the selection of a poly-
mer for a field trial, and a re-piping design modification for the municipal
by-pass was made. The field trial began in mid-February and the results to
date are encouraging. Since the results are tentative, definite conclusions
cannot be made; however, it is important to note the changes that have taken
place since the implementation of the field trial:
1) Bulking sludge problems have been eliminated in both aeration
systems. Note: The bulk N and P addition systems were opera-
tional prior to the implementation of the changes, and both
aeration systems receive nutrients.
2) Discharge standards are presently being met.
3) Overall average loading to the aeration process appears to be
higher with the change in wastewater character. Limited data
indicate that a very high fraction of municipal BOD had been
removed with the mill wastewater in primary treatment.
4) The activated sludge has taken on a much healthier dark color
as a result of the increased inert solids contained in the
city wastewater. Prior to the by-pass, the MLSS always took
on the color of the variable mill wastewater.
5) The SVI has become established at a level of 70-90, and the
process appears to be reasonably stable.
6) Polymer addition has had a beneficial effect on solids de-
watering, producing a large decrease in sludge volume.
In addition to the solution implementation activity of Phase IV, other
important work is being directed at characterizing the mill wastewater and
aeration system influent. A detailed sampling and analysis program is being
conducted to better define the loading parameters. Two months of data col-
lection for total COD, soluble COD, SS, and starch has yielded some very
useful information on the critical mill operations as they relate to the re-
sulting wastewater. Also, this effort will allow the effectiveness of poly-
mer addition to be completely evaluated over an extended period.
376
-------
DISCUSSION
In the course of solving a number of activated sludge process problems
similar to the one described in this paper, the author has observed that cer-
tain key fundamental oversights in design and operation tend to be made all
too often. Sufficient emphasis is not put on ensuring that a proper aeration
system environment will be maintained at all times. This critical area of
process design is especially important in situations where troublesome indus-
trial wastewaters are encountered, as evidenced by the example discussed in
this paper. The following discussion includes specific comments about the
Brewer joint treatment facility, as well as some general comments related to
design and operation of similar facilities.
Adequacy of Original Design
The original design of the Brewer treatment facility did not give proper
consideration to "the variability in magnitude and character of the industrial
wastewater. Average values for loading were not sufficient to ensure the
maintenance of a proper aeration system environment. The diurnal loading
examples shown in Figures 12 through 14 were found to be critical factors in
the establishment of bulking problems. In general, extremely high loading
periods that cause deficient environmental conditions to exist, even for only
short periods, can be detrimental to process stability. In the case of
Brewer, the relative short-term periods of high loading accounted for much of
the entire organic load during the day. This loading, in turn, produced much
of the net microbial growth for the day. Since these periods of high loading
stimulated the growth of filamentous bacteria, establishment of bulking con-
ditions was very rapid. The variability in character of the mill wastewater
was also neglected. It has been found that there are periods of mill opera-
tion in which solids (fiber) do not settle. Prior to polymer addition these
events overloaded the aeration process. Also, the character of the mill
wastewater is highly variable in terms of the soluble starch content, and this
is also an important factor to aeration system loading.
Design consideration for N and P addition was made in relation to aver-
age conditions. Therefore, the failure to recognize the deficiencies which
could occur with higher than average mill loading caused the designer to
incorrectly assume that the city wastewater could supply excess N and P. The
importance of N and P is well documented and should always be given proper
consideration with a nutritionally poor wastewater.
Beyond N and P, the lack of either a trace mineral or key amino acid
(protein) or vitamin could have been considered. The literature clearly
reflects problems of this nature associated with wastewaters having a nutri-
tionally unbalanced character. Sawyer (4), in 1940, discussed the problems
a small city would have when it accepted the wastewater of an industry of
this type. Further, the natural surface water supply for the Brewer area is
extremely devoid of dissolved minerals. Several key mineral elements are
routinely reported as being absent in the water analysis for the city. This
water is among the softest in the country, at levels of hardness around
10 mg/L as CaCO^. While it has not been determined that a mineral deficiency
was the true cause of the problem during high carbohydrate loading, the
377
-------
nature of the water before contamination certainly is very low in mineral
content. It could be speculated that with very high carbohydrate loading,
the mineral pickup through domestic use might not be adequate to supply the
required key trace minerals important in the metabolism of these compounds.
At a minimum, the design could have taken the direction of the work described
in this paper; i.e., minimize the unbalanced character of the combined
wastewater.
As a summary, the following design modifications have been required to
date:
1) Installation of a 10,000 gal. bulk anhydrous ammonia nitrogen
addition system.
2) Installation of a 4,000 gal. bulk phosphoric acid addition
system.
3) Modification of plant piping system to allow proper by-pass of
the city wastewater to the aeration system.
4) Installation of a permanent polymer addition system at the mill.
Operation and Process Stability
The sophistication of the intended operation was not adequate. Since
the variability of the mill wastewater was not given proper consideration,
many additional operation requirements are necessary. The plant was designed
without provision for any automated D.O. monitoring system, and for single-
shift operation during the day. Therefore, no means of controlling the
aeration rate in response to the highly variable loading was provided during
most of each day. Addition of N and P for economic operation now requires a
minimum monitoring test once every three hours, on a 24-hr, basis. Even with
this degree of monitoring, both N and D.O. can reach critical levels between
sampling times. Unfortunately, there is no predictable pattern of variation
as one finds with municipal wastewater. High demands can occur at any time,
and the operator must be able to respond. This requires an increased opera-
tions effort compared to what was originally anticipated.
In general terms, an activated sludge process must have sufficient
"dynamic stability" to handle extremes in loading. Very few treatment facil-
ities are without loading variation. Domestic or municipal plants are sub-
ject to diurnal hydraulic and organic loading variations which are reasonably
consistent and predictable. While these variations cause related variation—
in process performance parameters, the extremes are such that attenuation of
influent loading is rarely required. Since diurnal patterns are consistent
over time, the process will respond naturally to the influent loading.
Industrial wastewaters are entirely different than domestic or municipal
wastewaters, in terms of influent loading variation. Rather than reflecting
the habits of a community population, the wastewater variations result from
industrial processes and related operations. Where extremes in loading are
significantly greater than a comparable municipal wastewater, the designer
378
-------
must provide some method of attenuating these extremes or suffer a loss in
process stability. Examples of design decisions that might accomplish this
are spill prevention basins, equalization basins, aerated lagoon treatment,
or the option of joint treatment.
For Brewer and Eastern Fine Paper Company, the option of joint treatment
was intended to provide the Eastern wastewater with nutrients, necessary for
biological treatment. In this specific situation, the original joint facil-
ity process design was risky, at best. The industrial loading required that
supplemental N and P be added, and created aeration system loading extremes
that put severe stress on the biological process. This resulted in a com-
plete loss of dynamic stability through the establishment of a filamentous
sludge. Being a relatively high-rate process the facility could not handle
the combined wastewater without additional industrial loading attenuation
prior to the aeration system.
Future Work
Future work at the mill and treatment facility will be conducted to
ensure that the discharge standards are met at all times and at a minimum
operation cost. Past operation has been expensive in terms of the required
design modifications, excess power costs for maintenance of high D.O. levels,
N and P addition without bulk chemical economics, continuous polymer addi-
tion,etc. It is anticipated that future costs will be minimized as the new
process operation is optimized.
Continued work at the mill will include additional effort with the poly-
mer system and a completion of the wastewater characterization program. Some
possible residual problems with the chemistry of the mill wastewater may
require further study to define the impact of clay, suspended fiber, and
starch on the process. The mill has exhibited an excellent attitude con-
cerning the implementation of the recommended solution and has been a key
participant in the progress made to date.
Work at the treatment plant will be continued to:
1) optimize the N and P addition levels,
2) define the new aeration system loading more thoroughly,
3) determine the operational staffing which will be required
for monitoring purposes on a continuous basis,
4) provide an adequate D.O. monitoring system.
Regulatory Aspects
The Brewer, ME. situation raises some interesting questions with regard
to responsibility for correction of problems that are associated with the
original design of a treatment facility. In this case it was up to the city
and industry to provide a solution to a problem that was largely due to the
initial design and subsequent approval by the regulatory agency. All costs
379
-------
for solution were provided by the city and industry. These costs could have
been funded along with the facility had the designer provided a proper design
initially. While it is probably true that no design is perfect, a better
design should have been provided in this case. This becomes especially im-
portant when one considers the resulting expense and effort the city and
industry expended to accomplish the progress made to date.
In arriving at a solution to a problem of this nature, several key
ingredients are required:
1) a fundamentally sound solution approach,
2) ample leniency by the regulatory agencies to allow time for
proper evaluation of the problem and solution implementation,
3) adequate cooperation between the municipality and industry.
All three requirements are critical to the success of the effort, and the
loss of one or more elements creates a severe setback in the rate of progress.
While there are always some disagreements between the parties involved in
such matters, in this case it was fortunate that cooperation between all par-
ties concerned ultimately has resulted in what is hoped to be a permanent
solution.
REFERENCES
1. Gray A. C., et al., "Operational Factors Affecting Biological
Treatment Plant Performance," presented at the 51st Annual
Conference of Water Pollution Control Federation, Anaheim, CA,
1978.
2. Hegg, B. A., et. al., "Evaluation of Operation and Maintenance
Factors Limiting Municipal Wastewater Plant Performance -
Phase II," presented at the 51st Annual Conference of Water
Pollution Control Federation, Anaheim, CA, 1978.
3. Lowry, J. D., Wastewater Treatment Performance Evaluation -
Brewer, ME, Vol. 2, November, 1979.
4. Sawyer, C. N., "Activated Sludge Oxidations - The Influence of
Nutrition in Determining Activated Sludge Characteristics,"
Sewage Works, 12, 1, January, 1940.
380
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UNIROYAL CHEMICAL'S EXPERIENCE WITH COMBINED
MUNICIPAL-INDUSTRIAL WASTEWATER TREATMENT
AT ELMIRA, ONTARIO
K. C. Bradley
Uniroyal Chemical,
P. 0. Box 250, Elmira, Ontario, N3B 3A3, Canada.
ABSTRACT
The Chemical- Division of Uniroyal Ltd. produces in Elmira a wide range
of organics for use in the agricultural and rubber chemical industries. Pro-
cess waste waters from this chemical complex are combined with raw sewage
from the Town of Elmira prior to primary clarification and secondary treat-
ment in a joint municipal/industrial treatment system. Some of the implica-
tions of the way we chose to accept the concept of combined treatment are
presented. Because we have experienced treatment in this Ontario Ministry
of the Environment operated shared cost plant for the past fourteen years,
some thoughts on operating experience are also presented. Changes made, and
proposed, to up-grade treatment include modifications to the aeration sys-
tem, improved equalization, activated carbon pretreatment, and effluent
filtration. Studies providing direction for these changes have been carried
out by the Ministry of the Environment and by Uniroyal.
INTRODUCTION
The Chemical Division of Uniroyal Ltd. produces in Elmira wide range of
organics for use in the agricultural and rubber chemical industries. During
the mid-nineteen fifties the Town of Elmira and Uniroyal recognized that
additional treatment was necessary for the aqueous wastes from both sources,
TEXT
The close proximity of the Town of Elmira and Uniroyal sewer discharges
(see Figure 1), the possibility of similar treatment processes, and the
economics of a shared plant as opposed to two separate systems, provided
all that was necessary for the study of a co-operative effort for waste
water treatment. In fact, laboratory and pilot studies by Uniroyal
Chemical soon indicated that we might treat our entire process waste waters
in a shared activated sludge treatment plant for less than the chemical costs
used to treat one major process waste stream.
Several concepts were examined by Uniroyal including the following:
381
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1. Separate treatment;
2. Combined treatment;
3. Combined treatment with separation of clean cooling water; and
4. Separate treatment with separation of clean cooling water.
The most reasonable and cost-effective approach seemed to be the third
concept and for three reasons. (1) Much of our clean cooling water was
already in separate pipes. (2) A lower volume would reduce treatment plant
costs. (3) There was some doubt at that time that activated sludge would
really work on the concentrated industrial process wastes alone. Although
our industrial process wastes without cooling water were very strong, use
of the town sewage as dilution water would ensure that activated sludge
could still be a good potential candidate for treatment of both Uniroyal and
town waste waters together.
By choosing this joint treatment plant concept with separation of clean
cooling water, we were" not only choosing the most cost-effective solution
for our situation at that time, but we were indirectly committing ourselves
to the interesting long term waste treatment policy of maintaining a minimum
process waste volume. We were also agreeing to other conditions, namely:
1. We would not have full control over operation of the treatment process.
2. As a major contributor of BODr we could be singled out for any treat-
ment failures or inadequacies of the whole treatment plant. (On the other
hand, the combined wastes would tend to moderate effects of an interfering
substance from any one source).
3. We would discharge less organics than with two separate plants.
Effluent quality objectives at that time included 15 ppm. BOD5 for each
secondary activated sludge treatment plant. Separate plants including a
mixture of process wastes and cooling water in one, and town sewage in the
other, would have provided for a greater number of Ib./day BOD5 in the total
of the two discharges than that from one joint plant receiving only Uniroyal's
process waste waters diluted with town sewage.
It is interesting to speculate on how different things might have been
had we chosen to build separate plants:
1. It would have cost more for both us and our town.
2. We would have had to operate our industrial waste plant entirely by
ourselves.
3. We would have had to locate and use our own industrial treatment plant
sludge disposal sites. (In Ontario this would not be easy.)
A. We would not be engaged in cost-sharing discussions every time major
changes were considered.
382
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5. Our cooling water most likely would have been used as a diluent; so any
additional treatment such as carbon adsorption or effluent filtration would
probably reflect the costs of dealing with much larger volumes.
6. A higher degree of treatment would be necessary to achieve the same
overall town plus Uniroyal discharge of BOD to the receiving stream. Where
pollutants are measured in Ib./day as well as ppm., this can be very
significant.
Construction of the joint Town of Elmira - Uniroyal Water Pollution
Control Plant (WPCP) began shortly after design approval by the old Ontario
Water Resources Commission. It was started up in late 1964 as a four-stage
plug flow 10.6 hr. aeration detention time system, Figure 2. Probably
because of shocks from a variation in waste water characteristics, the
system was soon modified to approximate a complete mix system.
This, plus improved equalization at Uniroyal, allowed the bacterial
population to stabilize, but effluent quality was still not good. The mixed
liquor level was raised to the 5,000 to 8,000 mg./l. level in an effort to
get a low soluble BOD5 in the effluent. Unfortunately for the most part, as
the MLSS concentration rose, the specific uptake rate (SUR) dropped so that
the overall oxygen utilization barely changed. We then went through our
whole manufacturing complex and re-directed all individual waste streams
having more than 100,000 rag. COD per litre to alternate disposal outside of
Elmira. We reasoned that if we starved the organisms, they would learn to
do a more complete job of degrading our complex organics. A low soluble
BOD^ resulted, but the colour and COD still remained high.
At this point we examined the addition of powdered activated carbon to
the aeration system, the use of granular activated carbon on the final
effluent, and pretreatment of our industrial discharge to the joint WPCP
with granular activated carbon. We decided on the pretreatment scheme for
two reasons. It was the lowest cost approach and it promised to enable the
WPCP to provide a good effluent. Following installation of this system
some evidence of nitrification appeared in the WPCP for the first time. Now,
several years later, the WPCP must be modified so that the effluent will be
nitrified. Had we installed our carbon system on the WPCP effluent, it
would have been doubtful that we would ever have a nitrifying bacterial
population in the WPCP. On the other hand, with tertiary carbon treatment,
maybe nitrification would not be necessary.
Although we use town sewage for dilution, we wonder if some bio^-
oxidation problems may be caused by the natural changes in the degree of
dilution. For example, the town sewage diurnal flow pattern shows variations
by a factor of 10 or 20. The same variation, though not as often, can
occur from day to day with changes in the weather. We hope the diurnal flow
equalization basin proposed for the town sewage will provide the solution
to our remaining bio-oxidation problems.
Our combined wastes WPCP is now undergoing a major expansion and up--
grading. This is required because of the expansion of the town and general
up-grading of effluent criteria. See Figure 3. Because Uniroyal has an
383
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agreement with the Town for a specified portion of the treatment plant, and
contributes to its cost of operation, Uniroyal is a member of a technical
committee, along with the Town's consultant, and the Ontario Ministry of
the Environment, to determine the most appropriate design to satisfy all our
treatment needs. So far the committee has agreed on the design and cost-
sharing with Uniroyal for the first part of the expansion / up-grading
system. Modifications will, among other things., include the following items:
1. Diurnal flow equalization for the town sewage.
2. Full conversion to the complete mix process.
3. Improved effluent clarification.
4. Final effluent filtration.
5. Discharge of Uniroyal waste directly to the aeration section.
6. Volumetric design capacity increase of 47% to accommodate an increase
in the town's population.
The second part of the WPCP up-grading involves nitrification. Labora-
tory studies for this part are still in progress. Once completed, we will
again establish a fair cost share, and then work out a new agreement for
sharing the plant operating costs. Because the second phase requires
nitrification, it is perhaps fortunate that we long ago separated clean
cooling waters from our process wastes. A carbon pretreatment system for
five or ten times the volume to remove the organics inhibitory to nitrify-
ing organisms would have been considerably more expensive than the system
we installed. If we had the equally more expensive tertiary carbon treat-
ment and still required nitrification in the secondary system, a second
carbon system up-stream would represent a comparatively enormous additional
investment in treatment costs. This suggests that by minimizing our volume
of contaminated aqueous wastes we saved ourselves a great deal in treatment
costs initially, now, and in the foreseeable future.
In summary, our joint system indicates the following:
1. Lower total volume (use of sewage as inorganic salt diluent in place of
clean industrial cooling water).
2. Less duplication of equipment, manpower, and testing services.
3. Fewer alterations whenever more stringent effluent quality requirements
are imposed. (One plant to alter in place of two.)
4. Lower cost pretreatment systems for the industrial wastes. (With
cooling water separation a more concentrated industrial waste results,
providing a wider variety of applicable pretreatment techniques to choose
from.)
This means that for municipal and industrial wastes, I believe that to
install and then up-grade a combined treatment system to meet the ever-
changing receiving stream requirements should most certainly be lower in
cost for both parties than for each to go it alone with separate systems.
384
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UNIROYAL 1
PROCESS I 1
WASTE
x, SEUERS
TOWN SEWER
TO HPCP
Figure 1. Town of Elmira.
385
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CREEK
DISINFECTION
CHAMBER
FINAL CLA1UFIERS
-
•*-
I
AEXATION
SECTION
-
-»
LAB
OFFICE
PRIMARY CLARIFIEK8
Figure 2. Municipal/Industrial Treatment
System.
COMBINED
INFLUENT
386
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FIGURE 3 SOME DISCHARGE CRITERIA CHANGES
Maximum 1957 1972 1979
Values For: Obj ectives Requirements Requirements
BOD5 (mg./l.) 15 10 7.5 (75 lb./
day)
SS (mg./l.) 15 15 15 (150 lb./
day)
Phenolic equivalent
(yg./l.) 20 20 6.5 (0.065
Ib./day)
TKN as Nitrogen
(mg./l.) ' - - 3.5 (Apr. 1
to Oct.
3D
Free NH as Nitrogen
(mg./l.7 - - 7.5 (Nov. 1
to Mar.
31)
387
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PB83-142398
INDUSTRIAL COMPATIBILITY WITH
THE POTW IN TAMPA, FLORIDA
THROUGH CITY/INDUSTRY COOPERATION
D. W. Pickard
City of Tampa
2700 Maritime Blvd.
Tampa, Florida 33605
ABSTRACT
A comprehensive industrial waste monitoring section was started on a
full scale basis in 1973, five years before the new AWT Plant construction
was complete. The Tampa AWT Plant treats waste from a service area with a
population of 300,000>and approximately 50 key industries. Industries in-
clude breweries, food processors, lead storage battery manufacturing, elec-
troplating, and printed circuit board manufacturing. Most pretreatment pro-
grams have involved industrial process changes in place of treatment plants,
thus producing little toxic residue. Pilot plants of the AWT process se-
lected for Tampa were run for approximately two years to verify the treat-
ability of the wastewater by the process of choice. Thru planning and in-
dustrial cooperation Tampa has maintained a combined wastewater that is com-
patible with the POTW.
INTRODUCTION
The City of Tampa began the planning stages for a new treatment plant
in 1968. During the planning stages a great deal of time was devoted to se-
lecting a process which would insure the treatability of the combined in-
dustrial and domestic wastewater. In 1973, before detail design work began,
the City ran a pilot plant which represented the treatment process of choice.
Also in 1973 a full scale industrial waste monitoring program was funded.
The purpose of the industrial waste monitoring section was to develop "User
Charge" and "Industrial Cost Recovery" systems dictated by PL 92-500 and also
to begin a pretreatment program which would insure proper operation of the
wastewater entering the new plant. After the plant was started up in
January of 1978 it was clear that the program was a success.
TEXT
DESCRIPTION OF THE TAMPA SERVICE AREA
The City of Tampa has a population of 300,000 with approximately 50 key
industries. The City is also headquarters for many firms with dry manufac-
388
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taring facilities. Most industry in Tampa produce either no liquid waste or
a waste which is compatible with the Publicly Owned Treatment Works (POTW).
Tampa industry is best characterized by Table 1.
TABLE 1 TAMPA INDUSTRIAL FLOWS
Industrial Category MGD
Brewing 1.454
Battery Mfg. 0.102
Metal Platers 0.04CT
Seafood Processing 0.877
Chemical Mfg. 0.015
Soft Drink Bottling 0.263
Dairy Processing 0.141
Meat Processing 0.053
Aluminum Can Mfg. 0.842
Food Processing 0.165
Power Laundries 0.124
Printed Circuit Board Mfg. 0.300
Misc. Industries 0.050
Total Industrial Flow 4.426
With an industrial flow of 4.4 MGD approximately 1.3 MGD has the potential to
contain toxic pollutants which could adversely effect the POTW. Another sec-
tion of the paper will explain how 0.85 MGD of this total was eliminated
from the potentially toxic category. The remaining 70% of the industry in
Tampa exerts an organic loading on the plant. The designers, having this
information, formulated a plant process which would have maximum flexibility
with regard to organic loading.
TREATMENT PLANT PLANNING
Planning for the new POTW in Tampa began in 1968. By 1971, studies
were underway to choose the best AWT process for Tampa wastewater. The City
was faced with having to remove 90% of the biochemical oxygen demand, sus-
pended solids, nitrogen, and phosphorus. Due to a high soluble BOD in the
influent the decision was made to go to a biological system in lieu of the
physical chemical system. In 1972, the consultants decided to conduct pilot
studies on the treatment process of choice. This process was a two stage
activated sludge system using pure oxygen for both carbonaceous and nitrifi-
cation steps. The system was designed to use alum in the fourth stage
carbonaceous reactors for phosphorus removal. Denitrification would take
place in down-flow deep bed sand filters using methanol as a carbon source.
In 1973 a pure oxygen pilot plant was moved to the Hookers Point site in
Tampa. Pilot studies were conducted for several months with the end result
389
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being the basis of design for the new City of Tampa AWT Plant. At this time
Federal funding for design and construction was obtained as a result of
PL 92-500.
As construction progressed another pilot plant was constructed in the
1976-77 time-frame. This pilot plant would serve not only as a training
function but also as a verification of the original design. The pilot ran
for over a year and served several purposes. During the year time period we
trained many operators on the new process and also tried several alternate
carbon sources to methanol in the denitrification process.
INDUSTRIAL WASTE PROGRAM
The Tampa industrial flow was characterized in a previous section. This
characterization was due to an extensive industrial waste program which was
funded and initiated in 1973 as a result of planning needs. Public Law
92-500 also stated that Industrial User Charge, Industrial Cost Recovery, and
Pre-treatment Systems would be required as a prerequisite to Federal funding
for a POTW. The industrial waste section was set up with the above require-
ments in mind. The main purpose of the section was to insure that industry
paid for what it discharged and did not discharge any quantity of waste which
would be toxic to the POTW. The User Charge and Grant Recovery systems were
formulated and written into the ordinance immediately.
Unlike the user charge system, the pretreatment program was more diffi-
cult to initiate. Our division took many samples to determine where we stood
as far as toxic pollutants were concerned. We considered BOD, SS, N, and P
as compatible -because the treatment plant was designed to remove these
pollutants.
TABLE 2 TYPICAL HEAVY METAL CONCENTRATIONS BEFORE THE PRETREATMENT PROGRAM
Metal
Cd
Cr
Cu
Pb
Zn
AWT Inf. Ibs/day
10.0
176.8
60.0
110.0
220.2
Values for other heavy metals were in most cases lower than the ordinance
limits. Florida, like most states, does not have adequate hazardous waste
disposal facilities. With this in mind we embarked on a different approach
to pretreatment. This approach revolved around the idea of "do the best you
can to remove the toxics without creating a toxic sludge which will need
disposal". Several of our large industries took the lead in this effort.
The aluminum can manufacturers which support the brewing and soft drink
industry in Tampa were the first to respond to the concept. Chromium was
used in their process as a cleaner and brightener before painting. The
390
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chromium rinse was completely eliminated and another process solution was
used which contained no toxic pollutants. This process change eliminated
90% of the chromium discharge to the sewer system.
Lead storage battery manufacturers responded with extensive water re-
cycling systems which not only saved on the water bill but also kept concen-
trated waste streams in the respective production areas. As a result of the
water recycling operation the battery plants also have a reclaimable waste
in the pasting area of the plant. The end result is that the lead concentra-
tion in the raw waste-water has been greatly reduced, with no toxic sludge
being produced.
Individual job shop platers have responded by making improvements in
housekeeping and rinsing techniques. Most small plating companies have re-
duced heavy metal levels to a fraction of what they discharged before the
program began. Again a great reduction was achieved without creating a
sludge which-would need disposal. Two plating ships;which plate cadimum may
still have to install some minor pretreatment processes.
The only industry which has decided to go to a pretreatment system is a
printed circuit board manufacturer. This plant is about ready to go on line.
The resultant sludge will have to be shipped out of state for proper disposal.
The POTW influent can now be characterized by the following table which
expresses present heavy metal levels and sources.
TABLE 3 INFLUENT HEAVY METAL CONTRIBUTIONS LBS/DAY
MetalAWT Inf.Industrial PointPotable
Sources Water Supply
Cd 3.0 0.39 0.75
Cr 31.5 3.4 1.13
Cu 34.5 11.8 6.4
Pb 17.3 4.7 5.3
Zn 39.0 6.1 25.9
The same data expressed as percentages from known and unknown sources
is expressed in Table 4. It should be noted that even with what we feel is
a very accurate industrial survey much of the pollutant load is unidentified.
391
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TABLE 4 PERCENT HEAVY METAL CONTRIBUTION
Metal
Cd
Cr
Cu
Pb
ZN
Industrial Point
Sources
13
11
34
27
16
Potable
Water Supply
25
4
19-
31
66
Other
Sources
62
85
47
42
18
The pretreatment program has resulted in heavy metal effluent values
which are lower than Florida's strict water quality standards. Concentra-
tions given in Table 5 represent effluent from the AWT Plant before the allow-
ed mixing zone.
TABLE 5 AWT EFFLUENT HEAVY METALS
Metal
Cd
Cr
Cu
Pb
Zn
AWT Effluent
mg/1
0.007
0.035
0.014
0.046
0.028
Class III Water Quality
Standards mg/1
0.005
No Limit
0.015
0.03
0.03
All of the above results have been obtained thru industry/city cooperation.
The significant difference in this and other pretreatment programs is that
only a small amount of toxic sludge is produced. Our present pretreatment
program is being redesigned to meet all EPA guidelines and pretreatment
standards.
AWT PLANT PERFORMANCE DATA
The Hookers Point Advanced Wastewater Treatment Plant was started up on
January 28, 1978, almost 10 years after planning began. The plant is de-
signed to treat 60 MGD of combined domestic/industrial wastewater. Due to
the high organic load and high soluble BOD the plant was designed to treat
shock loads of organic pollutants. The plant influent and design perfor-
mance is characterized in Table 6.
392
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TABLE 6 AWT DESIGN CRITERIA
Parameter Influent Effluent
mg/1 mg/1
BOD 224 20
SS 221 20
N 32 , 3
p 12 1
Since the plant was designed some of the organic loadings have in-
creased. This is du-e to expansions at the breweries and increased food
processing.- Plant influent for 1979-80 is 'characterized in Table 7.
- TABLE 7 1979-80 INFLUENT CHARACTERISTICS
Parameter Influent
BOD 367
SS 267
N 26.4
P 8.9
The plant-has achieved much better treatment than the pilot plants
would have indicated. State standards have changed since the plant was de-
signed. Advanced wastewater treatment standards now require 5 mg/1 BOD,
5 mg/1 SS, 3 mg/1 total nitrogen and 1 mg/1 total phosphorus. The plant is
only required to remove 90% of the BOD, SS, N, and P. In June of 1979 the
City obtained a variance on the phosphorus removal requirement to a level of
7.5 mg/1. Actual plant performance can be characterized in Table 8.
TABLE 8 ACTUAL PLANT PERFORMANCE
Plant Data State Stds. NPDES Limits
% Rem Eff mg/1 % Rem Eff mg/1 Eff mg/1
BOD 98 5.4 90 5 30
SS 99 2.5 90 5 25
N 91 2.3 90 3 5
P 48 4.6 90 1* 2*
*New variance limit of 7.5 mg/1.
393
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SUMMARY & CONCLUSIONS
Through advanced planning and city/industry cooperation the City of
Tampa AWT Plant has performed far better than was anticipated. A different
approach to pretreatment has produced excellent results and very little
toxic sludge. Again city/industry cooperation was the key to reduced toxic
pollutants in the City of Tampa wastewater.
394
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PB83-142406
SOURCES OF TOXIC POLLUTANTS FOUND
IN INFLUENTS TO POTW'S
R. Seraydarian
R. Frederick
D. Ehreth
USEPA, Washington, D.C.
ABSTRACT
The purpose "of the project was to determine the origin of, and magnitude
of, the problem of toxic substances in Publicly Owned Treatment Works (POTW).
A major objective of the Monitoring and Data Support Division Study was to
determine the relative significance of the major source types - residential,
commercial and industrial - in contributing priority toxic pollutants to
POTW influents. The collection system from eleven residential areas, ten
commercial areas, and five industry-dominated areas in four different cities
were sampled. The influent to the POTW and tap water were also sampled. All
of the 129 priority pollutants were looked for, but 67 were not found in
collection systems of four POTW's. The most prevalent pollutants detected
were metals, solvents, and phthalate ester plasticizers. Industrial sources
appear to dominate the loading on the POTW for most pollutants, while resi-
dential and commercial contributions are still important for some pollutants,
although at a lower total loading when industrial sources are not present.
The type and size of industry present was a significant factor in detecting
the presence and concentration levels of the priority pollutants.
INTRODUCTION
Congress significantly amended the Federal Water Pollution Control Act
by the Clean Water Act of 1977 (CWA), largely as a result of national em-
phasis on controlling toxic pollutants. Toxic water pollutants, also called
priority pollutants, include at least 65 listed toxic substances and catego-
ries of substances resulting from the 1976 suit by the Natural Resources De-
fense Council (NRDC) and others. The list of 65 was later alternatively de-
fined as 129 specific inorganic and organic compounds. The Environmental
Protection Agency has developed a comprehensive program to promulgate guide-
lines to control the 129 toxic substances in industrial effluents. EPA is
also developing a strategy for controlling toxic pollutants in urban systems.
395
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EPA's Office of Water Planning and Standards (OWPS) was given the re-
sponsibility to develop a comprehensive regulatory strategy for toxic pollu-
tants in urban systems. Development of the strategy requires the assessment
of the magnitude of the toxic pollutant problem in sewage treatment plants,
characterization of the fate of the toxic pollutants in treatment plants, and
determination of the sources of these toxic poutants into POTW's. Knowledge
of the presence or absence of toxic pollutants,-and their sources is essential
to an effective pretreatment program as well as to an overall urban control
strategy.
This paper reports the result of a study to determine the relative sig-
nificance of the major source categories - residential vs. commercial vs.
industrial - in loadings to POTW influents.
A POTW service area in each of four cities was monitored for the prior-
ity pollutants. In each city, specific sampling sites were selected to rep-
resent each of the major source categories. In total, 11 residential, 10
commercial, and 5 industrial sites were sampled in addition to the tap water
and POTW influents.
OBJECTIVES OF THE SOURCE STUDY
The program had several major objectives: 1) to generate a small data
base for use in addressing a set of questions concerning priority pollutants
in POTW's:
• Which of the pollutants were present in each source category
(and which were not)?
• What is the frequency and relative mass loadings contributed
by each source for each pollutant?
• What effect does degree of industrialization have on POTW
influent concentrations?
• Can the mass loading indices from various sources be used to
effectively predict the influent concentrations to the POTW?
2) To provide some information about the reliability of the analytical
data generated. This objective has been achieved by establishing a substan-
tial quality assurance/quality control program.
CITY SELECTION
The cities selected for the project monitoring program were a subset of
the 40 cities selected by the Office of Water Planning and Standards (OWPS)
for study under the program to determine the fate of the priority pollutants
in POTW's. Three major constraints were imposed upon the 40 POTW's selected
for monitoring:
396
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1) Only those plants employing secondary or better treatment technology
were to be considered;
2) Only plants with average daily influent flows greater than or equal
to 5.0 MGD were to be considered; and
3) Only those treatment facilities located within standard metropolitan
statistical areas (SMSA's) were to be considered.
However, selection of the four cities to be included in the source study
required consideration of a number of other -factors regarding the size of the
service area and sampling logistics.
Plant and basin size were important considerations because each appeared
to have a bearing upon the diversity of socio-economic activity that existed
within an area. As was learned early in this program, plants with small
daily influent flows (5 to 10 MGD) were frequently located in areas where
only one type of activity was present. For example, many of the basins that
exhibited low influent rates (5-10 MGD) were comprised of virtually all
(90-95%) residential activity, with very little (5-10%) commercial activity
and almost no industrial component (0-1%). Conversely, one plant with an
average daily influent of 12 MGD had a flow mix which was nearly 99% indus-
trial. Any of these plants would have been acceptable if the project's goals
were only to assess one source's contributions independent of the others; but
inasmuch as an assessment of all three was desired concurrently, these types
of sites were excluded from further consideration. We expect to pursue this
approach to confirm our indices as the project progresses.
A second problem encountered in several of the smaller basins (with
respect to the area of land drained) was that even when a basin was identi-
fied which contained all three activities (residential, commercial and indus-
trial) , it was frequently impossible to isolate these activities in the
collection system. This difficulty usually developed because the smaller
basins were frequently interconnected by single interceptors, where waste-
water from one activity would drain through another, prior to reaching the
POTW.
The identification of proper sampling zones was also considered to be
important. Since the final goal of this study was to enumerate the pollu-
tion burden of at least two socio-economic activities at a minimum in each
basin, areas typifying both of these had to be identified, and segregated if
possible. It was desirable to locate duplicate areas within a basin because
this allowed for an immediate confirmation of results under conditions that
were equivalent.
Another factor considered important to the selection of a candidate
facility related to the availability of background or supportive data. Of
particular importance was the availability of demographic information which
is needed to describe the activity within the particular sampling zones
selected and within the basin as a whole. However, supplementary data, such
as 201 and 208 studies, facility plans, and inflow/infiltration assessment
were also available.
397
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Similarly, it was essential that the identified facility have detailed
maps of the collection system. Without having access to these maps, it is
virtually impossible to select appropriate sampling locations because the
area drained cannot be outlined.
The geographic location of the facility was also used as a criterion in
the selection process. Although one reason for including this issue per-
tained to the climate of the area during the analysis period, the main reason
for considering it related to the issues of the possible variability of
groundwater and soil chemistry across the country. Other factors considered
included congestion of the sample site areas, the accessibility of a major
airport, and the availability of rental vehicles and supplies.
The willingness of the local authorities to participate and cooperate in
the study was also a prime consideration in city selection.
The four cities were selected sequentially based on the results of the
prior cities. Table 1 summarizes the geographical and service area informa-
tion for the four cities.
SAMPLE COLLECTION
All sampling consisted of grab samples taken at each site every 3-4
hours and composited over a 24- or 48-hour period. Automatic samplers were
not used because of the difficulty in obtaining volatile samples with the
automatic equipment installed in the manhole. Actual collection was com-
pleted using a two-liter stainless steel graduate (bucket) and a telescopic
pole (extended length of 9.75 meters). Normally the first aliquot obtained
was used to determine pH, temperature and to determine whether oxidizing
species were present (by means of a potassium-iodide, starch indicating paper
test). This volume was then discarded and additional aliquots were obtained
to fill a predetermined number of sample bottles. Prior to leaving a site to
move onto the next site, an instantaneous flow measurement was made and the
results recorded. These flow measurements were used in the laboratory to
flow composite all appropriate increments into the final sample for chemical
analysis.
TABLE 1. SUMMARY OF CITIES SELECTED
Geographical
Location
City
City
City
City
A
B
C
D
Midwest
Midwest
Southwest
Northeast
Size of
Service Area
29
36
140
65
sq.
sq.
sq.
sq.
miles
miles
miles
miles
POTW % Industry Res.
Flow (1) (by flow) Sites
10
24
80
40
MGD
MGD
MGD
MGD
1%
12%
18%
7%
TOTAL
2
3
2
4
11
Comm.
Sites
2
2
3
3
10
Ind.
Sites
0
2
3
0
5
398
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Flow measurements were initually obtained using a depth of flow/Manning
equation approach. In practice, the measured depth of water contained within
a pipe can be used to determine the rate of water flow, if certain physical
parameters of the pipe (pipe diameter, slope, and roughness coefficient) are
also known. However, subsequent to the first area studied, the accuracy of
this approach was questioned because values obtained appeared to be unex-
plainably high. Similar observations were also obtained in the next two
cities, but in these instances confirmation that the measured flows were too
high was obtained by the results of theoretical flow balances.
The theoretical analysis was based on the assumption that the residen-
tial contribution to the basin flow was 100 gallons per day per person, and
that all other activities (commercial, industrial, municipal, etc.) dis-
charged as much as they consumed. By obtaining the water billing records of
the area, it was possible to estimate a dry weather flow throughout a basin
or for any individual site.
As a result of these theoretical analyses, additional flow measurement
procedures were evaluated during the fourth city study. Included among the
alternative procedures were a direct velocity determination/depth of flow
approach, a Palmer-Bowles flume/Manning dipper approach and a Palmer-Bowles
flume/Manning equation approach.
The results of this study indicated that either of the first approaches
produced more reliable estimates of the actual flow rate than did the depth
of flow/Manning equation technique. However, the flume/Manning dipper tech-
nique was somewhat more difficult to implement due to the additional effort
required to install both the flumes and the dippers. Therefore, the velocity/
depth of flow method was used to correct or recalibrate all depth of flow/
Manning equation results that had been obtained from the first three city
studies. The flow data used for the analyses in this report are all based
on the velocity measured (or corrected) flow for each sampling site.
QUALITY ASSURANCE/QUALITY CONTROL
A substantial quality assurance/quality control program was incorporated
into the sources investigation in order to document the reliability of the
data obtained. This quality assurance/quality control (QA/QC) program re-
quired certain of the samples taken in the field to be put through a proce-
dure which determines recoverability of each pollutant, reproducibility of
the analytical results, and a check for laboratory or field contamination. •*-
The POTW program was essentially a screening process. Yet, reproducible,
accurate data were also needed rather than approximate quantitative data.
For the QC samples, a total of 121 priority pollutants were added into dupli'-
cate field samples and into "clean" water samples (method reference stan-
dards) . Further, since the concentration levels were unknown, all priority
pollutants were added into samples blind, rather than basing the levels on
the concentration levels found in the field samples. Figure 1 presents the
five aliquots associated with a QC sample. Initially 30 percent of the
samples were chosen as QC samples. The samples were chosen to represent a
range of sample matrices. Field blanks, calibration standards, and instru-
ment performance check standards were analyzed routinely.
399
-------
It was also necessary for all analysts previously not using the proce-
dure to practice by analyzing- method reference standards. Satisfactory per-
formance had to be demonstrated before proceeding with the analysis of any
field samples. Procedures in the EPA Screening protocol were detailed and
distributed to all analysts before analyzing any samples.
The emphasis in the POTW QA/QC program was to obtain data on all the
priority pollutants and not just those known to be present in the field sam-
ples, thereby providing a basis for understanding the behavior of all prior-
ity pollutants when using the EPA Screening Protocol and decreasing the num-
ber of false positive or false negative results.
An additional feature of the POTW QA/QC program was the use of "total
method" internal standards. The use of these internal standards was initi-
ated with the samples for the third city. Four "total method" internal stan-
dards were added to the aqueous samples for the Acid and Base/Neutral analy-
ses. Figure" 2 summarizes the sampling and spiking procedures for each QA
sample. The precision and accuracy data obtained for these standards pro-
vided an efficient and cost effective means for monitoring the quality of
priority pollutant data being obtained on each and every sample (field and
QC) analyzed. It must be recognized that the use of these standards does not
replace the QC sample to which all the priority pollutants were added. Each
pollutant has its own chemistry and may present problems in a particular
type of sample matrix. Therefore, QC samples (A,B,C,D,F) were still analyzed
over a range of sample matrices, in order to check the behavior of all prior-
ity pollutants with respect to the various matrices.
A summary of the recovery data is summarized in Table 2. Recoverabili-
ties averaged between 77% and 100% with a standard deviation of 7% to 26%.
The overall precision for the priority pollutants improved throughout the
program, due in part to increased familiarity with the analytical procedures.
However, the overall improvement was also due to special attention given to
the data. The analytical laboratory (Arthur D. Little, Inc.) continually
modified the EPA procedures, resulting in a higher quality of data.
RESULTS AND DISCUSSION
The most important result from this study is that relatively few prior-
ity pollutants were found in the sources. Table 3 lists those 67 pollutants
that were never detected in any of the samples. Many of the pollutants were
detected at low concentrations and were observed infrequently. Figures 3
through 7 summarize the average frequency and concentration levels for the
priority pollutants detected more than 50% of the time and at average con-
centration greater than 10 ug/L in tap water, residential, commercial, and
industrial areas, and the POTW influent. The data has been grouped accord-
ing to those chemicals observed at levels less than 10 ug/L, 10-100 ug/L, and
at levels greater than 100 ug/L. The increase in both number and concentra-
tion of priority pollutants is observed as one progresses from tap water
through residential and commercial sources to the industrial sources. How-
ever, it is necessary to compare masses if one is to be able to quantify
loadings from each source.
400
-------
FIGURE 1
DESCRIPTION OF QUALITY CONTROL
SAMPLES
Raw Wastewater
Sample
Clean Water
Blank
Aliquot 1 + Spike =
Aliquot 2 + Spike =
Aliquot 3 =
+ Spike
A
B
C
D
F
One Set for
Each Analysis
Category
A, B,C, D, F—-Extract-
Each
Separately
Concentrate—Analyze
401
-------
Time I.Toko
All Dottles for
All Fractions
'
Extract by
Approprlalo
Procedures
FIGURE 2
QA SAMPLE SCHEMATIC
Analyze
) (
^^-/ Sample Point V^_^
'
/ Time 2. Take \
All Bottles lor
V. All Fractions J
Each
^-^
(Tlme3. Take
All hollies lor
All Fractions
1 Fraction ^
(Flow \^e^^~
Composite j
'
f
{ spin Y
__^-*-^ Composite y^~^^
i
^^^^^^
Waslewolor
Aliquot
1
Spike With
Known
Cocktail
t
Add Internal
Standard
,
I Spiked \
1 Sample 1
Waslewalor
Aliquot
t
Spike With
Known
Cocktail
"
Add Internal
Standard
jf
/ s
/ Rcpllcale
1 Spikud
V Sample
\ f
1
Extract by
Appropriate
Procedures
t
Extract by
ApproprLile
Procedures
1
Analyze
J ^ Analyze j (
-------
Analysis of the summarized data for each collection system studied showed
that for City A (about 1% industrial) the residential sources dominate the
mass flow to the POTW. For City B (12% industrial) residential sources are
a significant percentage of the loading, but many pollutants are dominated
by the industrial flow. For City C (18% industrial) the analysis shows a
clear dominance of mass loadings from industrial sources. For those situa-
tions where little industrial contributions exist, the total loading to the
POTW is significantly lower than when industry is also contributing to the
POTW.
Tap water contributed primarily trihalomethanes and copper. Residential
sources had high zinc, copper and manganese levels, plus some other metals.
Concentration levels for most pollutants, especially metals, appear to be
substantially higher from old residential areas compared to newer residential
areas, but the presence and frequency of pollutants did not vary significant-
ly. Commercial sources were quite similar to residential sources, but did
have some additional pollutants and a few more metals. Table 4 summarizes
the overall average concentrations for the 11 residential and 10 commercial
areas. The industrial sources had high concentrations of many of the de-
tected organic pollutants and all of the observed metals were present in this
source category.
TABLE 2. CHEMICAL ANALYSIS ACCURACY AND PRECISION SUMMARY FOR ALL 4 CITIES
Method Reference Standard*
Analysis Category
Volatiles
Acids
Base /Neutrals
Pesticides and PCB's
Total Cyanides
Total Phenols
Metals
Classical Parameters
Average
Recovery
92
79
79
77
96
97
100
81
Average Std
Deviation
18
16
21
14
8
7
26
14
Raw Wastewater
Average
Recovery
88
88
72
75
91
96
94
—
Avg Std
Deviation
23
16
19
15
12
11
18
—
*Standards spiked into pure distilled water.
In order to characterize the major sources, it was attempted to develop
mass loading indices for each priority pollutant detected. These indices
could prove useful in predicting the POTW influent concentrations for a spe-
cific service area. They would also provide general background levels for
analysis of the effectiveness of various industrial pretreatment alterna-
tives; i.e., they might be used to predict if the reduced loading at the in-
dustrial plant would be adequate to protect the POTW and sludge quality.
Because of the large variability in the presence and concentration
levels from various industrial sources, it does not seem valid to develop
overall indices to characterize industrial areas. However, if the specific
industries discharging to a POTW can be identified, industrial effluent mon-
itoring data will be available to estimate the priority pollutant levels
from each industry.
403
-------
TABLE 3. POLLUTANTS (67 TOTAL) NEVER DETECTED IN FOUR CITIES
101 Chloromethane
102 Dichlorodifluoromethane
103 Bromomethane
107 Acrolein
122 Cis-l,3-dichloropropylene
202 Nitrophenol
208 2,4-dinitrophenol
209 4,6-dinitro-2-cresol
211 4-Nitrophenol
304 Hexachloroethane
305 Bis(chloromethyl)ether
306 Bis(2-chloroethyl)ether
307 Bis(2-chloroisopropyl)ether
308 N-Nitrosodimethylamine
309 Nitrosodi-n-propylamine
311 Hexachlorobutadiene
313 2-Chloroethyl vinyl ether
314 Bis(2-chloroethoxy)methane
316 Isophorone
317 Hexachlorocyclopentadiene
318 2-Chloronaphthalene
319 Acenaphthylene
320 Acenaphthene
321 Dimethyl phthalate
322 2,6-Dinitrotoluene
323 4-Chlorophenyl phenyl ether
324 Fluorene
325 2,4-Dinitrotoluene
327 1,2-Diphenylhydrazine
328 N-Nitrosodiphenylamine
329 Hexachlorobenzene
330 4-Bromophenyl phenyl ether
336 Benzidine
340 Chrysene/Benzo(a) anthracene
342 3,3'-Dichlorobenzidine
343 Benzofluoranthenes*
345 Benzo(a)pyrene
346 Indeno (l,2,3-c,d)pyrene
347 Dibenzo(a,h)Anthracene
348 Benzo(g,h,i)perylene
349 TCDD
401 alpha-BHC
402 gamma-BHC
403 beta-BHC
405 delta-BHC
407 Heptachlor epoxide
408 Endosulian I
409 DDE
410 Dieldrin
411 Endrin
412 DDD
413 Endosulfan II
414 DDT
415 Endrin aldehyde
416 Endosulfan sulfate
417 Chlordane
418 Toxaphene
419 PCB-1221
420 PCB-1232
421 PCB-1242
422 PCB-1248
423 PCB-1254
424 PCB-1260
425 PCB-1016
503 Beryllium
*Two compounds
For the residential areas, we attempted to use the population as an in-
dex basis. Thus, for the residential sites, a per capita discharge rate
might be calculated as follows:
mass/person/day = concentration x flow
population
For reporting convenience, the residential values have been developed
in units of mg/person/day. The total service area residential contribution
may thus be estimated as:
RES(kg/day) = Res. Ave. (mg/person/day) x Population x 10
-6
404
-------
TABLE 4. OVERALL SOURCE AVERAGE CONCENTBATIONS
Pollutant
110
111
112
113
114
115
116
117
120
121
123
125
127
128
129
130
203
204
210
301
315
326
333
337
338
501
502
504
505
506
507
508
509
510
511
512
513
514
601
602
703
704
705
706
707
708
1 , 1-Dichloroethylene
1 , 1-Dichlorethane
Trans-l,2-Dichloroethylene
Chloroform
1, 2-Dichloroethane
1,1, 1-Trichloroethane
Carbon Tetrachloride
Bromodichloromethane
Trichloroethylene
Benzene
Dibromochloromethane
Bromoform
1,1,2, 2"-Tetrachldroethylen
Toluene
Chloobenzene
Ethyl Benzene
Phenol
2 , 4-Dimethylphenol
Pentachlorophenol
Dichlorobenzenes
Naphthalene
Diethyl Phthalate
Di-n-butyl Phthalate
Butyl Benzyl Phthalate
Bis (2-Ethylhexyl)Phthalate
Antimony
Arsenic
Cadmium
Chromium
Copper
Lead
Manganese
Mercury
Nickel
Selenium
Silver
Thallium
Zinc
Total Cyanides
Total Phenols
Ammonia
Oil and Grease
TSS
TOC
COD
BOD
ug/L*
Res. Com.
.0
.0
. .0
3.0
.1
2.3
.0
.0
.4
.2
.0
.0
6.3
2.6
.1
.4
5.8
.7
1.2
2,8
2.1
9.8
9.0
6.8
6.8
2.7
4.8
1.8
16.3
72.1
97,3
153.0
.4
4.2
3.8
2.2
.0
214.0
1.1
30.8
14.2
77.4
156.8
81
263.8
113.9
.3
.1
1.5
6,7
.1
2.9
.1
1,0
12.8
2.7
.7
.0
21.4
11.0
.0
3.0
4.5
.0
5.8
7.5
2.6
5.7
11.7
10.6
7.7
.3
2.6
.6
56.8
54.5
49.8
224.8
.4
12.4
3.3
2.9
.1
138.1
.2
10.7
10.7
109.0
122,4
106.2
346.0
160.0
*Classicals in mg/L
405
-------
Less Than 50%
Greater Than 50%
Greater
Than
100 yg/L
Between
10 yg/L
and
100 yg/L
Lead
Less
Than
10 yg/L
Chloroform
Zinc
Copper
Bromodichloromethane
Dibromochloromethane
Manganese
Figure 3.
Concentration/Frequency of Occurrence: Tap Water
406
-------
Less Than 50%
Greater Than 50%
Greater
Than
100 yg/L
Between
10 yg/L
and
100 yg/L
Less
Than
10 yg/L
Zinc
Manganese
Lead
Copper
Chromium
Total Phenols
Chloroform
1,1,2,2-Tetrachloroethylene
Toluene
Nickel
Selenium
Figure 4.
Concentration/Frequency of Occurrence: Residential
407
-------
Less Than 50%
Greater Than 50%
Greater
Than
100 pg/L
Trichloroethylene
Di-n-butylphthalate
Between
10 yg/L
and
100 pg/L
Less
Than
10 Pg/L
Manganese
Zinc
1,1,2,2-Tetrachloroethylene
Toluene
Butylbenzylphthalate
Copper
Lead
Chromium
Nickel
Total Phenols
Chloroform
Bromodichloromethane
1,1,1-Trichloroethane
Benzene
Ethylbenzene
Silver
Figure 5,
Concentration/Frequency of Occurrence: Commercial
408
-------
Less Than 50%
Greater Than 50%
Greater
Than
100 pg/L
Between
10 yg/L
and
100 ug/L
1,1-Dichloroethylene
Trans-l,2-dichloroethylene
Carbon Tetrachlorlde
2,4-Dimethylphenol
Pentachlorophenol
Bis(2-ethylhexyl)phthalate
Cadmium
Less
Than
10 ug/L
Ethylbenzene
Phenol
Dichlorobenzenes
Silver
Copper
Nickel
Chromium
Lead
Manganese
Zinc
Total Phenols
Chloroform
Trichloroethylene
1,1,1-Trichloroethane
1,1,2,2-Tetrachloroethylene
Toluene
Naphthalene
Di-n-butylphthalate
Total Cyanides
Benzene
Bromodichloromethane
Dibromochloromethane
Figure 6.
Concentration/Frequency of Occurrence: Industrial
409
-------
Less Than 50%
Greater Than 50%
Greater
Than
100 yg/L
Naphthalene
Butylbenzylphthalate
Antimony
Between
10 yg/L
and
100 yg/L
Less
Than
10 yg/L
Chromium
Manganese
Zinc
Trichloroethylene
1,1,1-Trichloroethane
1,1,2,2-Tetrachloroethylene
Toluene
Ethylbenzene
Dichlorobenzenes
Copper
Lead
Nickel
Total Cyanides
Total Phenols
Chloroform
Benzene
Diethylphthalate
Di-n-butylphthalate
Cadmium
Silver
Figure 7.
Concentration/Frequency of Occurrence:
POTWInfluent
410
-------
For the commercial sites, the only index reliably available for all of
the sites studies is the total flow. Thus, for these sources' types, an
average concentration value has been calculated so that, when the average
value is multiplied by the total basin source type flow, the total source
contribution value has been calculated so that, when the average value is
multiplied by the total basin source type flow, the total source contribu-
tion is obtained:
COM (Kg/day) = [Avg. Com. Conc.(ug/L)] x [Com. Flow(Lps)] x 8.64 X 10-5.
In order to evaluate the potential impact of the various sources on the
POTW influent, the above indices were used to calculate the projected POTW
loadings for several hypothetical situations. Table 5 shows the fraction
contributed from each source type for a city with the following character-
istics:
POTW Flow - 1,000 Lps
Residential Flow - 500 Lps
Residential population~114,000 People
Commercial Flow - 200 Lps
Industrial Flow - 300 Lps
The industrial flow was used with an overall industrial index calculated
for the 4 cities sampled to estimate the industrial loading. The hypotheti-
cal city with 30% industrial flow shows a clear domination by industrial
sources for all but a few of the priority pollutants.
OWPS is presently attempting to verify these indices by comparing the
predicted POTW influent loadings with actual influent loadings for cities
that have been monitored for priority pollutants under other EPA studies.
411
-------
TABLE 5. RELATIVE SOURCE STRENGTH COMPARISON
Fraction
110
111
112
113
114
115
116
117
120
121
123
125
127
128
129
130
203
204
210
301
315
326
333
337
338
501
502
504
505
506
507
508
509
510
511
512
513
514
601
602
703
704
705
706
707
708
1, 1-Diceloroethylene
1 , 1-Diceloroethane
Trans-1, 2-Dichloroethylene
Chloroform
1, 2-Dichloroethane
1,1, 1-Trichloroethane
Carbon Tetrachloride
Bromodichloromethane
Trichloroethylene
Benzene
Dibromochloromethane
Bromoform
1,1,2, 2-Tetrachloroethylen
Toluene
Chlorobenzene
Ethyl Benzene
Phenol
2 , 4-Dimethylphenol
Pentachlorophenol
Dichlorobenzenes
Naphthalene
Diethyl Phthalate
Di-n-butyl Phthalate
Butyl Benzyl Phthalate
Bis (2-Ethylhexyl) Phthalate
Antimony
Arsenic
Cadmium
Chromium
Copper
Lead
Manganese
Mercury
Nickel
Selenium
Silver
Thallium
Zinc
Total Cyanides
Total Phenols
Ammonia
Oil and Grease
TSS
TOC
COD
BOD
Res.
.00
.00
.00
.34
.08
.03
.00
.06
.06
.15
.05
.00
.18
.12
.17
.01
.17
.02
.35
.02
.05
.93
.34
.12
.32
.83
.86
.07
.06
.63
.32
.55
.34
.09
.83
.06
.00
.35
.06
.33
.77
.53
.66
.59
.57
.56
Com.
.02
.03
'.08
.18
.12
.02
.00
.28
.24
.50
.28
.00
.14
.11
.02
.02
.02
.00
.18
.01
.03
.07
.07
.04
.07
.02
.05
.02
.05
.08
.06
.18
.08
.06
.12
.01
.49
.06
.00
.07
.09
.19
.09
.14
.13
.14
Ind.
.98
.97
.92
.48
.80-
.95
1.00
.67
.70
.35
.67
.00
.68
.77
.81
.97
.82
.98
.47
.97
.92
.00
.59
.85
.61
.15
.09
.91
.89
.29
.61
.27
.58
.85
.05
.93
.51
.59
.94
.59
.14
.28
.25
.26
.30
.29
O LHU
Kg/day*
.30
.04
.33
.65
.02
2.32
.74
.06
.94
.09
.04
.00
2.66
1.76
.03
2.69
4.31
1.96
.55
10.05
1.43
1.44
2.95
5.15
1.84
.29
.94
.59
20.80
11.23
13.66
21.97
.08
3.33
.46
4.20
.00
37.81
2.51
8.91
2.02
9.81
22.65
12.85
46.05
19.21
"Classicals in 10 kg/day
412
-------
REFERENCES
1. U.S. EPA, "Quality Assurance Program for the Analyses of Chemical
Constituents in Environmental Samples," Environmental Monitoring
and Support Lab., Cincinnati, Ohio, March 1978.
2. U.S. EPA, "Sampling and Analysis Procedures for Screening of
Industrial Effluents for Priority Pollutants, EMSL, Cincinnati,
Ohio, March 1977, revised April 1977.
3. Arthur -D. Little,- Inc. , Summary of QA/QC Experience on POTW Sources
Program, EPA Contract No. 68-01-3857, February 1980, (unpublished).
4. Arthur D. Little, Inc., Report No. ADL 81099-63, Sources of Toxic
Pollutants Found in Influents to Sewage Treatment Plants, Contract
No. 68-01-3857, October 1979, (unpublished).
5. Callahan, Michael, A., And Ehreth, Donald J., Sources of Toxic
Pollutants Found in Influent to Sewage Treatment Plants, March 1979.
413
-------
TREATMENT AND REMOVAL OF PRIORITY INDUSTRIAL POLLUTANTS
AT PUBLICLY OWNED TREATMENT WORKS
H. D. Feller
P. J. Storch
Burns and Roe Industrial Services Corporation
P.O. Box 663
Paramus, New Jersey 07652
A. Shattuck
U.S. Environmental Protection Agency
401 M. Street S.W.
Washington, D.C. 20460
ABSTRACT
The U.S. Environmental Protection Agency has initiated a program to
study the fate of priority pollutants in 40 POTW's distributed across the
United States. Thus far, 20 POTW's have been sampled and data from nine
plants has been obtained. The nine plants' data have been summarized and
evaluated. Mechanisms for priority pollutant treatment and removal and the
impact of industrial flow on POTW influent toxic pollutant concentrations
are discussed. Removal efficiencies and approximate calculations of "con-
sistent removals" are presented. Finally, concentration factors for priority
pollutants in POTW sludges and mass balances were calculated and are pre-
sented.
INTRODUCTION
In 1978, the United States Environmental Protection Agency (EPA) em-
barked upon a program of study designed to elucidate the occurrence and fate
of 129 selected toxic organic and inorganic pollutants (priority pollutants)
in Publicly Owned Treatment Works (POTW's). The scope of this project in-
cludes week-long, round-the-clock sampling at 40 POTW's across the United
States. Samples collected are subsequently analyzed for the priority
pollutants as well as conventional and selected non-conventional parameters.
Currently, 20 POTW's have been sampled and data for 9 plants have been re-
ported and evaluated. In this paper, data summaries for these first nine
plants are presented. Specific phenomena regarding the fate of these
pollutants in POTW's will also be discussed.
414
-------
Additionally, the impact of industrial contributors on toxic pollutant
incidence in raw wastewater and POTW ability to treat or remove these pollu-
tants are covered. Finally, a hypothetical analysis of the possible revision
of categorical pretreatment limitations based on incidental removal or treat-
ment in the POTW is presented.
Treatment and Removal of Toxic Pollutants in POTW's
In evaluating the fate of toxic pollutants in POTW's, it is useful to
highlight the contrast between the terms "removal" and "treatment," which
are often used interchangeably. This is improper since removal and treat-
ment refer to different types of phenomena. For a pollutant to be treated,
it must be eliminated completely. -That is, the pollutant's physical form is
changed such that the material is no longer an environmental concern. Con-
versely, removal only implies pollutant transfer. Specifically, the removed
pollutant is" transferred from the waste stream in question to a location
which may or may not be more environmentally acceptable. For example, bio-
degradable pollutants are treated in POTW's, whereas metallic pollutants,
which are chemical elements, are not changed but only removed, concentrating
in POTW sludge streams.
Removal or treatment of toxic pollutants in a POTW can occur as a result
of various physical, chemical or biological processes that take place within
the treatment system. The exact combination of these phenomena affecting any
particular priority pollutant depends largely on the nature of the pollutant
itself, and the POTW unit operations applied to that pollutant.
Physical mechanisms fall into three broad categories: removal as a
solid with other suspended solids, adsorption onto suspended solids with sub-
sequent removal, and atmospheric stripping. Removal of toxic pollutants with
suspended solids in primary sludge is most prevalent for the heavy metals.
Combination of the heavy metals with alkalinity or sulfide will produce in-
soluble species that settle out of raw sewage simultaneously with other
wastewater solids.
Adsorption onto solid surfaces provides an additional removal mechanism
for some organic priority pollutants. If an organic material is insoluble
in water, slightly soluble or hydrophobic, the organic pollutant may prefer-
entially adsorb on solid surfaces. In raw sewage, both suspended solids and
floatables (greases) may be available for sorption. Therefore, when scum or
primary sludge is removed, organic priority pollutants, which may be concen-
trated in these materials, may also be removed.
A significant proportion of the organic priority pollutants is rela-
tively volatile. It has been postulated that during aeration some of these
materials may be air stripped and subsequently released to the atmosphere.
This phenomena might account for some observed removals of biologically re-
fractory volatile organics, especially aromatic species, in activated
sludge plants.
415
-------
Chemical treatment of toxic pollutants generally is applicable to or-
ganic materials which may come in contact with strong oxidants in the POTW.
Most commonly, chlorine used for disinfection or odor control reacts with
organic pollutants. At times, the organic species are simply chlorinated,
sometimes creating toxic materials. However, treatment may occur when the
oxidation of the organic material goes to completion, destroying the toxic
pollutant and forming carbon dioxide and water.. Chlorine is not the only
oxidant used within a POTW which could destroy organic pollutants. Hydrogen
peroxide, which is sometimes used to control filamentous bulking, or ozone,
which is gaining acceptance as a disinfectant, can also provide beneficial
oxidation and destruction of organic pollutants. Oxygen from aeration pro-
cesses may also contribute to the oxidation of some materials.
Under the proper conditions, organic toxic pollutants may be biological-
ly treated by acting as substrate for organisms in the treatment plant's
biomass. Aliphatic compounds are generally more amenable to breakdown in
biological systems than aromatic compounds, straight chain aliphatics being
most easily degraded. In order for an organic pollutant to compete as a
food source with normal organic constituents in sewage (carbohydrates, pro-
teins, fatty acids, etc.), certain conditions should be maintained, such as
acclimation to the possible toxic effects of the pollutant. If these con-
ditions can be met, significant removal by biodegradation can occur.
A sometimes overlooked mechanism for the removal of inorganic priority
pollutants via biological processes is the uptake of trace quantities of
these pollutants as micronutrients. These materials may find their way into
the biomass as a result of being complexed and incapsulated in a material
that is consumed by cells.
POTW Selection
Presently, about 20 plants have been sampled as part of the 40 plant
POTW program. The goal of the project is to obtain priority pollutant data
representative of major POTW characteristics as are currently common in the
United States. Table 1 presents the characteristics of the nine plants cov-
ered in this paper.
Primary factors considered in selecting the plants included:
Treatment processes
POTW size
Amount of industrial contribution
Type of industrial contribution
POTW operating efficiency
Operation as a percent of design capacity
POTW location representing all EPA regions
The plants selected have been and will represent the full spectrum of
common treatment processes in use today. However, since activated sludge
and trickling filter plants are most prevalent, the 40 plants will be heavily
weighted with those types. POTW size is measured by design flow. Because
the General Pretreatment Regulations (40CFR 403) generally affects only
416
-------
TABLE 1 POTW CHARACTERISTICS
Treatment
Process
Design
Flow, MCD
Avg. Flow
MGD
% Ind.
Contrlb.
BOD
ln£/Eff
TSS
Inf/Eff
Major
Industrial
Contrlb.
1
Conv.
AS
120
90
30
237/20
254/27
Pliarm. ,
Petro-
chemical,
Plating,
Found .
Coking,
Foods
2
Conv .
AS
15
7
2
89/15
155/22
Grain
Stg.,
Oil/Fuel
Terra. ,
Machine
Tools,
Metaluk.
3
AS
lit
10-11
10
185/23
120/20
Chicken
Process,
Plastics,
Textiles
it
Conv.
AS
120
80-85
8
207/40
180/70
Beverages,
Plating,
Painc&lnk,
Chemicals,
Foods,
Paper,
Photo
Process.
Plant
5
AS
25
19
10-15
219/21
170/29
Auto Mfg.
Hospitals,
Plating,
Paper,
Photo
Process .
6
Contact
Stab. ,AS
7.4
6
26
230/25
290/30
Plastics
& Syn.
Found. ,
Bakery
7 89
AS + Conv,
AS TF AS
66 50 60
50 20-25 45
15 11 9
110/10 168/10 125/9
130/15 256/15 137/14
Plating Auto Mfg. NA
Auto Pts.
Furn.
1
-------
TABLE 2 SUMMARY OF ANALYTICAL DATA
FRACTION
CONVENTIONALS
NON-CONVENTIONALS
VOLATILES
PARAMETER
BOD
TOTAL SUSP. SOLIDS
COD
OIL : GREASE
TOTAL PHENOLS
TOTAL SOLIDS
TOTAL VOLATILE SOLIDS
TOTAL VOL. SUS. SOLIDS
AMMONIA NITROGEN
TOC
ACRYLONITRILE
BENZENE
CARBON TETRACHLORIDE
CHLOROBENZENE
1,2-BICHLORDETHANE
1,1, 1-TRICHLORDETHANE
1 , 1-DICHLORDETHANE
1,1, 2-TRICHLORDETHANE
CHLOROFORM
1 , 1-DICHLORDETHYLENE
1 , 2-TRANS-D ICHLORDETHYLENE
ETHYLBENZENE
METHYLENE CHLORIDE
METHYL CHLORIDE
BROMOFORM
DICHLOROBROMOMETHANE
UNITS
MG/L
MG/L
MG/L
MG/L
UG/L
MG/L
MG/L
MG/L
MG/L
MG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
PLANT 1
INFLUENT
215
175
423
50
150
939
252
113
7
205
L 100
143
1
1
0
18
1
5
46
4
6
28
12
0
0
0
EFFIIJENT
PRE CL.
22
10
69
NOT RUN
NOT HJN
835
130
8
31
55
L 100
1
L 5
L 5
L 5
5
L 5
L 5
23
3
L 5
L 5
5
1 5
L 5
L 5
FINAL
EFFLUENT
13
20
68
5
13
834
262
14
5
65
L 100
3
L 5
1 5
1 5
3
L 5
1 5
19
4
1
4
6
L 5
L 5
1
PCNT
REM.
94
89
84
90
91
11
88
29
68
98
100
100
83
100
100
59
83
86
50
PRIMARY
SLUDGE
20167
46667
57500
8060
672
56667
26833
23333
59
23500
L 100
171
11
1. 5
1 5
24
11
L 5
L 35
9
23
276
222
L 5
L 5
57
WASTE
ACT.
SLUDGE
6033
6300
6717
373
30
6030
3293
4200
9
2717
3
10
6
L 5
L 5
I 5
L 5
I 5
'L 5
1 5
I 5
3
249
L 5
L 5
56
I
L
L
L
L
1
1
L
L
L
L
L
L
FLOT-
ABLES
0
0
0
0
0
1
1
0
1
0
0
0
0
5
5
0
5
5
5
5
0
0
1
5
5
0
POLLUTANTS NOT LISTED WERE NEVER DETECTED
L-LESS THAN: N-D NOT DETECTED:
PRELIMINARY DATA ONLY TO BE VERIFIED
(Continued)
-------
TABLE 2 (Continued)
PLANT 1
FRACTION
VOLATILES
ACID EXTRACT
BASE-NEUTRALS
PARAMETER
TRICHLOROFLUOROMETHANE
CHLORODIBROMOMETHANE
TETRACHLORDETHYLENE
TOLUENE
TRICHLORDETHYLENE
2,4,6-TRICHLOROPHENOL
PARACHLOROMETA CRESOL
2-CHLOROPHENOL
2,4-DIMETHYEPHENOL
PENTACHLOROPHENOL
PHENOL
ACENAPHINENE
1,2,4-TRICHLOROBENZENE
HEXAC HLO ROBEN ZEN E
1,2-DICHLOROBENZENE
1,3-DICHLOROBENZENE
1,4-DICHLOROBENZENE
3,3'-DICHLOROBENZIDINE
FLUORANTHENE
BIS(2-CHLORDETHYOXY) METHANE
HEXACHLOROBU TADIENE
NAPHTHALENE
BIS(2-ETHYLHEXYL) PHTHALATE
BUTYL BENZYL PHTHALATE
DI-N-BUTYL PHIHALATE
DI-N-OCTYL PHTHALATE
DIETHYL PHTHALATE
POLLUTANTS NOT LISTED WERE NEVER DETECTED
L-LESS THAN; N-D NOT DETECTED
PRELIMINARY DATA ONLY TO BE VERIFIED
UNITS
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
INFLUENT
0
0
51
28
28
0
0
L 50
L 50
1
16
0
0
0
3
1
3
L 25
1
0
0
4
27
2
5
0
3
EFFLUENT
PRE CL.
L 5
L 5
5
5
5
L 50
L 50
L 50
2
3
5
L 10
L 10
I 10
L 10
I 10
L 10
L 25
L 10
L 25
L 10
I 10
15
L 10
2
1 10
I 10
FINAL ,
EFFLUENT
0
L 5
5
4
4
L 50
L 50
1
1
1
21
L 10
L 10 "
L 10
1
1
1
1
2
L 25
L 10
2
14
2
3
1
1
PCNT
REM.
90
86
86
67
67
50
40
40
67
PRIMARY
SLUDGE
L 5
17
293
284
284
L 50
I 50
I 50
L 50
93
94
117
L 10
L 10
L 10
L 10
L 10
L 25
L 10
L 25
L 10
195
2231
1
L 10 1
L 10
L 10
WASTE
ACT.
SLUDGE
L 5
29
7
2
0
L 50
L 50
L 50
L 50
112
60
L 10
L 10
L 10
L 10
L 10
L 10
L 25
L 10
L 25
L 10
4
42
I 10
1 10
I 10
I 10
FLOT-
AliLliS
L 5
I 0
0
0
0
L 50
1 50
1 50
50
1
1
L 0
L 10
L 10
L 10
L 10
L 10
L 25
L 10
I 25
L 10
L 1
1
1 1
1
I 10
L 10
(Continued)
-------
TABLE 2 (Continued)
PLANT
FRACTION
BASE-NEUTRALS
METALS
PARAMETER
DIMETHYL PHTHALATE
1,2-BENZANTHRACENE
BENZO (A)PVRENE
3.4-BENZOFLU ORANTHENE
CHRYSENE
ACENAPHTHYLENE
ANTHRACENE
1/12-BENZOPERYLENE
FLUORENE
PHENANTHRENE
l/2:5,6-DIBENZANTHRACENE
INDEND(1,2,3-C,D) PYRENE
PYRENE
ANTIMONY
ARSENIC
BERYLLIUM
CADMIUM
CHROMIUM
COPPER
CYANIDE
LEAD
MERCURY
NICKEL
SELENIUM
SILVER
THALLIUM
ZINC
UNITS
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
NG/L
UG/L
UG/L
UG/L
UG/L
UG/L
INFLUENT
2
1
0
L 5
1
0
4
0
1
4
0
0
5
L 50
L 50
L 2
12
450
191
71
55
278
98
L 50
L 2
L 50
42
EFFLUENT
PRE CL.
L 10
I 10
L 10
L 5
L 10
L 10
L 10
L 25
L 10
L 10
L 50
I 50
L 10
L 50
L 50
L 2
3
42
13
NOT RUN
I 20
300
50
L 50
L 2
1 50
42
FINAL
EFFIlJENT
1
1
L 10
L 5
1
L 10
2
I 25
1
2
1
1
3
L 50
L 50
L 2
4
46
27
7
L 20
300
50
L 50
L 2
L 50
90
PCNT
REM.
50
50
50
40
67
90
86
90
100
59
100
66
PRIMARY
SLUDGE
L 10
479
L 10
675
479
L 10
1572
L 25
313
1572
L 50
L 50
754
146
1263
37
1220
14571 -
77429
627
46857
1000
13343
5
25
2
129714
WASTE
ACT.
SLUDGE
L 10
I 10
I 10
0
L 10
L 10
4
L 25
L 10
4
10
8
L 10
21
63
9
344
18071
8971
56
1594
286
3343
21
182
1
12829
FLOT-
ABLES
L 10
L 1
1 10
L 0
L 1
L 10
L 1
L 25
L 1
L 1
L 50
L 50
L 1
L 0
L 0
L 0
0
0
0
1 58
L 0
1
0
L 0
1 0
L 0
0
POLLUTANTS NOT LISTED WERE NEVER DETECTED
L-I.ESS THAN: N-D NOT DETECTED:
PRELIMINARY DATA ONLY TO BE VERIFIED
(Continued)
-------
X/VBLE 2 (Continued)
FRACTION
NON-CONV. METALS
PARAMETER
ALUMINUM
BARIUM
CALCIUM
IRON
MAGNESIUM
MANGANESE
UNITS
UG/L
UG/L
MG/L
UG/L
MG/L
UG/L
PLANT
INFLUENT
1458
129
83
2990
27
104
1
EFFLUENT
PRE CL.
137
45
86
289
30
124
FINAL
EFFLUENT
203
50
79
392
27
111
PCNT
REM.
86
61
5
87
PRIMARY
SLUDGE
NOT RUN
NOT RUN
NOT RUN
NOT RUN
NOT RUN
NOT HUN
WASTE
ACT.
SLUDGE
NOT RUN
NOT RUN
NOT RUN
NOT RUN
NOT RUN
NOT RUN
FLOT-
ABLES
NOT RUN
NOT RUN
NOT RUN
NOT RUN
NOT RUN
NOT RUN
POLLUTANTS NOT LISTED WERE NEVER DETECTED
L-LESS THAN: N-D NOT DETECTED:
PRELIMINARY DATA ONLY TO BE VERIFIED
-------
TABLE 3 SUMMARY OF ANALYTICAL DATA
FRACTION
CONVENTIONALS
NON-CONVENTIONALS
VOLATILES
PARAMETER
BOD
TOTAL SUSP. SOLIDS
COD
OIL & GREASE
TOTAL PHENOLS
TOTAL SOLIDS
TOTAL VOLATILE SOLIDS
TOTAL VOL. SUS. SOLIDS
AMMONIA NITROGEN
TOC
ACRYLONITRILE
BENZENE
CHLOROBENZENE
1 , 2-DICHLOROETHANE
1,1, 1-TRICHLOROETHANE
1,1-DICHLOROETHANE
CHLOROFORM
1, 1-DICHLOROETHYLENE
1, 2-DICHLOROPROPANE
ETHYLBENZENE
METHYLENE CHLORIDE
DICHLOROBROMOMETHANE
TRICHLOROFLUOROMETHANE
CHLOROD IBROMOMETHANE
TETRACHLOROETHYLENE
TOLUENE
TRICHLOROETHYLENE
UNITS
MG/L
MG/L
MG/L
MG/L
UG/L
MG/L
MG/L
MG/L
MG/L
MG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
PLAN'
•INFLUENT
95
97
183
24
20
619
143
54
12
70
L 100
10
0
1
1
0
5
2
0
2
9
1
L 5
0
5
5
2
[ 2
EFFLUENT
PRE CL.
20
12
52
NOT RUN
NOT RUN
496
129
7
70
29
L 100
1
0
1
0
L 5
4
1
L 5
0
4
1
0
1
3
3
0
FINAL
EFFLUENT
14'
9
38
8
3
567
132
6
71
28
1 100
3
L 5
1
0
L 5
5
2
L 5
0
4
2
L 5
1
3
3
0
PERCENT
REMOVAL
85
91
79
67
85
8
8
89
60
70
100
100
56
40
40
100 i
COMBINED
SLUDGE
8457
21714
32429
3551
454
25571
14206
12100
12707
11929
41
33
I 5
L 5
L 5
L 5
L 5
L 5
L *5
2
247
74
L 5
9
61
336
L 5
POLLUTANTS NOT LISTED WERE NEVER DETECTED
L-LESS THAN: N-D NOT DETECTED:
PRELIMINARY DATA ONLY TO BE VERIFIED
(Continued)
-------
TABLE 3 (Continued)
PLANT 2
NJ
FRACTION PARAMETER
ACID EXTRACT 2-NITROPHENOL
4-NITROPHENOL
PENTACHLOROPHENOL
PHENOL
BASE-NEUTRALS 1,2-DICHLOROBENZENE
1,3-DICHLOROBENZENE
1,4-DICHLOROBENZENE
3,3'-DICHLOROBENZIDINE
2,6-DINITROTOLUENE
FLUORANTHENE
ISOPHORONE
NAPHTHALENE
BIS(2-ETHYLHEXYL)PHTHALATE
BUTYL BENZYL PHTHALATE
DI-N-BUTIL PHTHALATE
DI-N-OCTYL PHTHALATE
DIETHYL PHTHALATE
DIMETHYL PHYTHALATE
1,2-BENZANTHRACENE
BENZO (A)PYRENE
3,4-BENZOFLU ORANTHENE
11,12-BENZOFLU ORANTHENE
CHRYSENE
ACENAPHTHYLENE
ANTHRACENE
PHENANTHRENE
PYRENE
POLLUTANTS NOT LISTED WERE NEVER DETECTED
L-LESS THAN: N-D NOT DETECTED:
PRELIMINARY DATA ONLY TO BE VERIFIED
UNITS
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
INFLUENT
L 50
L 50
1
4
4
1
1
L 25
1
2
1
4
10
5
4
3
4
2
L 10
1
1
1
L 10
L 10
1
1
2
EFFLUENT
PRE CL.
5
33
2
4
1
1
I 10
I 25
1 25
L 10
L 25
1
5
3
3
1
1
1
1
L 10
L 5
L 5
1
1
L 10
L 10
L 10
FINAL
, EFFLUENT
2
15
1
4
1
3
L 10
1
L 25
L 10
L 25
1
4
4
3
1
1
1
1
I 10
1 5
L 5
1
1
I 10
L 10
L 10
PERCENT
REMOVAL
75
100
100
100
100
75
60
20
25
67
75
50
100
100
100
100
100
100
COMBINED
SLUDGE
L 50
L 50
L 50
4
10
10
10
25
25
10
25
91
1486
1
10
10
10
10
0
L 10
43
L 5
8
L 10
91
91
45
(Continued)
-------
TABLE 3 (Continued)
PLANT 2
FRACTION
METALS
NON-CONV. METALS
PARAMETER
ANTIMONY
ARSENIC
BERYLLIUM
CADMIUM
CHROMIUM
COPPER
CYANIDE
LEAD
MERCURY
NICKEL
SELENIUM
SILVER
THALLIUM
ZINC
ALUMINUM
BARIUM
CALCIUM
IRON
MAGNESIUM
MANGANESE
MOLYBDENUM
SODIUM
TIN
TITANIUM
VANADIUM
YTTRIUM
UNITS
UG/L
UG/L
UG/L
UG/L
UG/L
UE/L
UG/L
UG/L
NG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
MG/L
UG/L
MG/L
UG/L
UG/L
MG/L
UG/L
UG/L
UG/L
UG/L
INFLUENT
L 50
L 50
L 2
4
71
54
77
16
214
30
L 50
1
L 50
278
537
74
58
1640
12
280
NOT RUN
NOT RUN
NOT RUN
NOT RUN
NOT RUN
NOT RUN
EFFLUENT
PRE CL.
L 50
L 50
L 2
L 2
26
11
NOT RUN
6
33
22
L 50
5
L 50
83
74
26
64
198
14
194
NOT RUN
NOT RUN
NOT RUN
NOT RUN
NOT RUN
NOT RUN
FINAL
EFFLUENT
L 50
L 50
L 2
L 2
22
10
142
3
57
20
L 50
0
L 50
52
51
25
65
188
12
175
6
6
6
6
6
6
PERCENT
REMOVAL
100
69
81
81
73
33
100
81
91
66
89
30
COMBINED
SLUDGE__
39
149
12
305
8114
10700
1819
7386
3286
3097
27
78
1
26743
NOT RUN
NOT RUN
NOT RUN
NOT RUN
NOT RUN
NOT RUN
NOT RUN
NOT RUN
NOT RUN
NOT RUN
NOT RUN
NOT RUN
POLLUTANTS NOT LISTED WERE NEVER DETECTED
L-LESS THAN: N-D NOT DETECTED:
PRELIMINARY DATA ONLY TO BE VERIFIED
-------
TABLE 4 SUMMARY OF ANALYTICAL DATA
PLANT
FRACTION
CONVENTIONALS BOD
TOTAL SUSP. SOLIDS
COD
OIL & GREASE
NON CONVENTIONALS TOTAL PHENOLS
TOTAL SOLIDS
TOTAL DISS. SOLIDS
SETTLEABLE SOLIDS
TOTAL VOLATILE SOLIDS
VOLATILE DISS. SOLIDS
k TOTAL VOL. SUS. SOLIDS
01 AMMONIA NITROGEN
TOC
VOLATILES BENZENE
1,1,1-TRICHLOROETHANE
1,1-DICHLOROETHANE
2-CHLOROETHYL VINYL ETHER
CHLOROFORM
1,1-DICHLOROETHYLENE
1,2-DICHLOROPROPANE
ETHYLBENZENE
METHYLENE CHLORINE
METHYL CHLORIDE
DICHLOROBROMOMETHANE
TRICHLOROFLUOROMETHANE
POLLUTANTS NOT LISTED WERE NEVER DETECTED
L-LESS THAN: N-D NOT DETECTED:
PRELIMINARY DATA ONLY TO BE VERIFIED
UNITS
MG/L
MG/L
MG/L
MG/L
MG/L
MG/L
MG/L
ML/L
MG/L
MG/L
MG/L
UG/L
MG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
INFLUENT
134
265
417
44
116
555
279
8
235
67
151
16
216
2
59
0
1
39
2
0
36
10
L 5
0
0
EFFLUENT
PRE CL.
12
12
49
6
11
322
293
L 1
76
69
4
1
24
L 5
2
L 5
L 5
7
L 5
L 5
L 5
3
L 5
1 5
1 5
FINAL
EFFLUENT
14
44
45
4
15
351
299
L 1
77
58
15
1
34
L 5
2
L 5
L 5
28
L 5
I 5
1 5
3
1 5
5
L 5
PCNT
REM.
90
83
89
91
87
37
100
67
13
90
94
84
100
97
100
28
100
100
70
PRIMARY
SLUDGE
5538
40039
44050
8304
3377
41947
1021
NOT RUN
29725
573
29065
120
21771
34
17
N-D
N-D
N-D
2373
10
203
8
33
N-D
N-D
COMB.
SLUDGE
4426
31859
22577
1799
1615
30020
6076
NOT RUN
20507
2619
17882
31
15194
2
N-D
N-D
N-D
N-D
N-D
N-D
93
1
N-D
N-D
N-D
GRAV ITY
THICK.
OVERFLOW
55
126
422
38
39
480
342
3
101
64
106
23
230
1 5
60
L 5
1 5
50
3
L 5
60
3
L 5
L 5
L 5
(Continued)
-------
TABLE 4 (COntined)
PLANT 3
FRACTION
VOLATILES
ACID EXTRACT
BASE-NEUTRALS
-P-
N>
CHLOROiyiBROMOMETHANE
TETRACHLOROETHYLENE
TOLUENE
TRICHLOROETHYLENE
VINYL CHLORIDE
PENTACHLOROPHENOL
PHENOL
1 , 2 , 4-TRICHLOROBENZENE
1,2-DICHLOROBENZENE
1 , 3-DICHLOROBENZENE
1 , 4-DICHLOROBENZENE
FLUORANTHENE
NAPHTHALENE
BIS(2-ETHYLHEXL) PHTHALATE
BUTYL BENZYL PHTHALATE
DI-N-BUTYL PHTHALATE
DI-N-OCTYL PHTHALATE
DIETHYL PHTHALATE
DIMETHYL PHTHALATE
1 , 2-BENZANTHRACENE
BENZO (A)PYRENE
3,4-BENZOFLUORANTHENE
11 , 12-BENZOFLUORANTHENE
CHRYSENE
ANTHRACENE
FLUORENE
PHENANTHRENE
PYRENE
POLLUTANTS NOT LISTED WERE NEVER DETECTED
L-LESS THAN: N-D NOT DETECTED:
PRELIMINARY DATA ONLY --- TO BE VERIFIED
UNITS
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
4
EFFLUENT FINAL PCNT
INFLUENT PRE CL. EFFLUENT REM.
L 5
45
13
2
L 5
L 50
25
L 10
0
0
0
0
3
29
6
7
4
5
2
0
0
0
0
0
2
L 10
2
0
L 5
6
1
1
L 5
L 50
L 50
L 10
L 10
L 10
L 10
1 10
L 10
9
L 10
3
L 10
1
L 10
L 10
L 10
L 5
L 5
L 10
L 10
L 10
L 10
L 10
1
3
I1
L 5
L 5
L 50
L 50
L 10
L 10
L 10
L 10
L 10
L 10
5
L 10
5
L 10
1
L 10
I 10
L 10
I 5
L 5
L 10
L 10
L 10
1 10
L 10
93
92
100
100
100
83
100
29
100
80
100
100
100
GRAVITY
PRIMARY COMB. THICK.
SLUDGE SLUDGE OVERFLOW
N-D
N-D
260
38
301
N-D
277
41
N-D
N-D
25
67
78
300
57
263
N-D
N-D
N-D
15
N-D
N-D
N-D
15
269
10
260
66
N-D
1601
54
N-D
N-D
30
4297
N-D
N-D
N-D
N-D
23
N-D
157
N-D
. 37
•N-D
N-D
N-D
N-D
N-D
N-D
N-D
N-D
104
N-D
104
32
L 5
50
20
3
L 5
L 50
10
L 10
L 10
L 10
L 10
L 10
5
30
L 10
5
L 10
L 10
L 10
L 10
L 10
L 5
L 5
L 10
L 10
L 10
L 10
L 10
(Continued)
-------
TABLE 4 (.Continued)
PLANT 3
FRACTION
METALS
NON-CONV. METALS
PARAMETER
ANTIMONY
ARSENIC
BERYLLIUM
CADMIUM
CHROMIUM
COPPER
CYANIDE
LEAD
NICKEL
SELENIUM
SILVER
ZINC
ALUMINUM
BARIUM
BORON
CALCIUM
COBOLT
IRON
MAGNESIUM
MANGANESE
MOLYBDENUM
SODIUM
TIN
TITANIUM
VANADIUM
YITRIUM
POLLUTANTS NOT LISTED WERE NEVER DETECTED
L-LESS THAN: N-D NOT DETECTED:
PRELIMINARY DATA ONLY TO BE VERIFIED
UNITS
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
MG/L
UG/L
UG/L
MG/L
UG/L
UG/L
MG/L
UG/L
UG/L
UG/L
UG/L
INFLUENT
L 4
3
L 1
4
29
285
96
97
62
1 4
1
317
2384
116
289
24
26
12028
4
343
147
58
40
159
71
4
EFFLUENT
PRE CL.
L 4
2.
1 5
1
7
39
53
30
42
L 4
L 4
70
79
L 1
252
27
6
116
3
17
152
67
3
3
28
4
FINAL
EFFLUENT
L 4
L 5
0
6
10
43
36
44
80
L 4
L 4
61
251
1
258
19
11
209
3
23
151
66
4
6
29
6
PCNT
REM.
100
66
85
63
55
100
81
89
99
11
21
58
98
25
93
90
96
59
PRIMARY
SLUDGE
130
403
13
229
4433
25667
20530
6.833
547
28
417
27667
NOT RUN
NOT RUN
NOT RUN
NOT RUtl
NOT RUN
NOT RUN
NOT RUN
NOT RUN
NOT RUN
NOT RUN
NOT RUN
NOT RUN
NOT RUN
NOT 'HJN
GRAVITY
COMB. THICK
SLUDGE OVERFLOW
52 14
130 5
10 LI
42 LI
4750 17
20500 195
7223 60
1475 45
478 44
12 L 4
338 L 4
16000 194
NOT RUN 711
NOT RUN 35
NOT RUN 109
NOT RUN 42
NOT RUN 11
NOT RUN 3402
NOT RUN 4
NOT RUN 303
NOT RUN 212
NOT RUN 64
NOT RUN 14
NOT RUN 59
NOT RUN 44
NOT RUN 2
-------
TABLE 5 SUMMARY OF ANALYTICAL DATA
PLANT
FRACTION
CONVENTIONALS
NON-CONVENTIONALS
-P-
NJ
CO
PARAMETER
BOD
TOTAL SUSP. SOLIDS
COD
OIL & GREASE
TOTAL PHENOLS
TOTAL SOLIDS
TOTAL DISS. SOLIDS
SETTLEABLE SOLIDS
TOTAL VOLATILE SOLIDS
VOLATILE DISS. SOLIDS
TOTAL VOL. SUS. SOLIDS
AMMONIA NITROGEN
TOC
BENZENE
CARBON TETRACHLORIDE
CHLOROBENZENE
1,2-DICHLOROETHANE
1,1,1-TRICHLOROETHANE
1,1,2-TRICHLOROETHANE
1,1,2,2-TETRACHLOROETHANE
CHLOROETHANE
DIS(CHLORIMETHYL) ETHER
2-CHLOROETHYL VINYL ETHER
CHLOROFORM
1,1-DICHLOROETHYLENE
1,2-TRANS-DICHLOROETHYL ENE
1,2-DICHLOROPROPANE
ETHYLBENZENE
POLLUTANTS NOT LISTED WERE NEVER DETECTED
L=LESS THAN: N-D NOT DETECTED
PRELIMINARY DATA ONLY —TO BE VERIFIED
VOLATILES
UNITS
MG/L
MG/L
MG/L
MG/L
MG/L
MG/L
MG/L
ML/L
MG/L
MG/L
MG/L
UG/L
MG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
INFLUENT
152
164
343
117
123
402
252
5
170
80
117
9
99
L 1
L 2
L 1
L 2
284
L 2
10
I 15
NOT RUN
L 8
8
13
25
L 1
44
FINAL
EFFLUENT
22
43
81
16
28
276
207
L 1
112
58
29
8
38
L 1
L 2
L 1
L 2
09
L 2
2
L 15
NOT RUN
L 8
3
3
7
L 1
L 1
PERCENT
REMOVAL
86
74
73
86
77
31
10
100
37
27
75
11
62
69
89
63
77
72
100
COMBINED
SLUDGE
18300
59667
59783
10120
677
63583
1290
6350
34683
1050
29933
207
35830
40
270
N-D
N-D
507
441
43
N-D
N-D
N-D
1
2347
54993
4
1467
DIGESTED
S1UDGE
5500
41917
34003
9040
1158
45917
859
4530
21533
405
15057
523
11503
20
N-D
252
55
37
N-D
194
1
1
1
1
3
9800
7
910
(Continued)
-------
TABLE 5 SUMMARY OF ANALYTICAL DATA
PLANT 4
FRACTION
VOLATILES
ACID EXTRACT
BASE NEUTRALS
PARAMETER
METHYLENE
DICHLOROBROMOME THANE
TETRACHLOROETHYLENE
TOLUENE
TRICHLOROETHYLENE
VINYL CHLORIDE
2/4-DIMETHYLPHENOL
2-NITROPHENOL
2,4-DINITROPHENOL
PENTACHLOROPHENOL
PHENOL
UNITS
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
INFLUENT
282
I 1
385
36
497
L 33
2
1 2
L 50
6
14
FINAL
EFFLUENT
128
L 1
134
2
37
I 33
L 1
L 2
L 50
L 5
1
PERCENT
REMOVAL
55
65
94
93
100
100
93
COMBINED
SLUDGE
142
04
950
984
467
N-D
N-D
N-D
N-D
25
103
DIGESTED
SLUDGE
16
N-D
10
1847
120
27
N-D
37
200
N-D
70
ACENAPTHLENE
1,2-DICHLOROBENZENE
1,3-DICHLOROBENZENE
1,4-DICHLOROBENZENE
FLUORANTHENE
ISOPHORONE
NAPTHALENE
N-NITROSODINE THYLAMIDE
DI3(2-ETHYLHEXYL) PHTHALATE
BUTYL BENZYL PHTHALATE
DI-N-BUTYL PHTHALATE
DIETHYL PHTHALATE
1,2-BENZANTHRACENE
3,4-BENZOFLUORANTHENE
CHRYSENE
ACENAPHTHYLENE
ANTHRACENE
FLUORENE
PHENAMTHRENE
INDENO(1,2,3-C,D) PYRENE
PYRENE
POLLUTANTS NOT LISTED WERE NEVER DETECTED
L-LESS THAN N-D NOT DETECTED:
PRELIMINARY DATA ONLY—TO BE VERIFIED
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
I 4
105
L 5
13
L 3
L 10
51
1 49
31
60
18
7
L 3
L 6
L 3
L 2
0
L 3
0
1
I 15
L 4
6
L 5
3
L 3
2
L 3
3
11
2
6
0
L 3
L 8
L 3
L 2
L 3
L 3
L 3
L 15
L 15
94
77
100
65
97
67
100
100
N-D
262
252
1128
114
N-D
640
N-D
8108
2650
427
N-D
15
23
13
N-D
602
19
602
N-D
121
65
116
10
125
51
N-D
445
N-D
8437
4400
33
N-D
6
25
6
28
375
38
375
N-D
90
(Continued)
-------
TABLE 5 SUMMARY OF ANALYTICAL DATA
PLANT 4
FRACTION
PESTICIDES
METALS
-P-
U)
o
NON-CONV. METALS
PARAMETER
DIELDRIN
HEPTACHLOR
ALPHA-DMC
GAMMA-DMC
ANTIMONY
ARSENIC
BERYLLIUM
CADMIUM
COPPER
CYANIDE
LEAD
MERCURY
NICKEL
SELENIUM
SILVER
ZINC
ALUMINUM
BARIUM
CALCIUM
IRON
MAGNESIUM
MANGANESE
SODIUM
UNITS
NG/L
NG/L
NG/L
NG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
NG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
MG/L
UG/L
MG/L
UG/L
MG/L
INFLUENT
5
13
L 30
55
L 50
L 50
L 2
80
47
37
127
1250
20
L 50
10
494
2460
151
16
7358
3
234
32
FINAL
EFFLUENT
L 30
L 20
5
163
L 50
L 50
L 2
29
17
12
53
450
7
L 50
3
223
584
38
36
2365
2
179
29
PERCENT
REMOVAL
100
100
64
64
68
50
64
65
83
55
76
75
68
33
24
9
COMBINED
SLUDGE
L 1000
L 1000
L 1000
1 1000
116
403
25
17667
10000
193
41000
NOT RUN
2567
20
1966
14333
NOT RUN
NOT RUN
NOT RUN
NOT RUN
NOT RUN
NOT RUN
NOT RUN
DIGESTED
SLUDGE
L 1000
L 1000
L 1000
L 1000
116
333
30
26167
15333
407
49333
NOT RUN
3083
23
2378
171667
NOT RUN
NOT RUN
NOT RUN
NOT RUN
NOT RUN
NOT RUN
NOT RUN
POLLUTANTS NOT LISTED WERE NEVER DETECTED
L-LESS THAN: N-D NOT DETECTED;
PRELIMINARY DATA ONLY—TO BE VERIFIED
-------
TABLE 6 SUMMARY OF ANALYTICAL DATA
PLANT
FRACTION
CONVENTIONALS
NON-CONVENTIONALS
-P-
u>
PARAMETER
BOD
TOTAL SUSP. SOLIDS
COD
OIL & GREASE
TOTAL PHENOLS
TOTAL SOLIDS
TOTAL DISS. SOLIDS
SETTLEABLE SOLIDS
TOTAL VOLATILE SOLIDS
VOLATILE DISS. SOLIDS
TOTAL VOL. SUS. SOLIDS
AMMONIA NITROGEN
TOG
BENZENE
CHLOROBENZENE
1,1,1-TRICHLOROETHANE
1,1,2,2-TETRACHLOROETHANE
2-CHLOROETHYL VINYL ETHER
CHLOROFORM
1,1-DICHLOROETHYLENE
1,2-TRANS-DICHLOROETHYLENE
1,2-DICHLOROPROPANE
1,3-DICHLOROPROPYLENE
ETHYLBENZENE
METHYLENE CHLORIDE
METHYL CHLORIDE
DICHLOROBROMOMETHANE
DICHLORODIFLUOROMETHANE
POLLUTANTS NOT LISTED WERE NEVER DETECTED
L-LESS THAN; N-D NOT DETECTED;
PRELIMINARY DATA ONLY — TO BE VERIFIED
VOLATILES
UNITS
MG/L
MG/L
MG/L
MG/L
MG/L
MG/L
MG/L
MG/L
MG/L
MG/L
MG/L
UG/L
MG/L
INFLUENT
130
147
374
33
30
889
742
7
400
360
120
12
64
FINAL <
EFFLUENT
13
12
60
3
8
695
683
L 1
371
360
11
7
14
PERCENT
REMOVAL
91
92
82
91
73
22
8
100
23
91
42
78
PRIMARY
SLUDGE
15671
26433
35203
4100
99
29064
3431
992
21597
2426
19182
35
7527
DIGESTED
SLUDGE
3102
17430
12712
2746
258
18407
1016
860
8712
359
8362
419
1275
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
5
0
19
1
1 8
12
1 1
2
L 1
4
10
676
L 34
3
L 30
1
1
3
L 1
L 8
7
L 1
L 2
L 1
L 2
1
468
34
2
5
80
84
100
42
100
100
90
31
33
42
N-D
N-D
40
N-D
2
22
1541
0
N-D
166
101
45
N-D
N-D
5
1
2
45
0
6
N-D
22
N-D
N-D
73
11
9
N-D
N-D
(Continued)
-------
TABLE 6
(Continued)
-P-
u>
PLANT 5
FRACTION
VOLATILES
ACID EXTRACT
BASE NEUTRALS
PESTICIDES
PARAMETER
CHLORODIBROMOMETHANE
TETRACHLOROETHYLENE
TOLUENE
TRICHLOROETHYLENE
VINYL CHLORIDE
2,4, 6-TRICHLOROPHENOL
2 , 4-DICHLOROPHENOL
2 , 4-DIMETHYLPHENOL
PENTACHLOROPHENOL
PHENOL
ACENAPHTHENE
1 , 2-DICHLOROBENZENE
1,4-DICHLOROBENZENE
FLUORANTHENE
NAPHTHALENE
DIS(2-ETHYLHEXYL) PHTHALATE
BUTYL BENZYL PHTHALATE
DI-N-BUTYL PHTHALATE
DI-N-OCTYL PHTHALATE.
DIETHYL PHTHALATE
ANTHRACENE
PHENANTHRENE
PYRENE
BETA-BHC
GAMMA-BHC
UNITS
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UC/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
NG/L
NG/L
INFLUENT
1
115
37
49
L 33
0
L 1
0
L 5
1
1 4
I 5
I 5
1 3
3
20
6
3
L 4
2
L 3
L 3
L 2
L 1000
I 1000
FINAL '
EFFLUENT
1
26
0
14
L 33
L 2
L 2
L 1
L 5
0
1 4
L 5
L 5
L 3
L 3
6
L 2
I 2
L 4
I 2
t 3
1 3
L 2
12
22
PERCENT PRIMARY
REMOVAL SLUDGE
3
77 14
100 199
71 163
1792
N-D
N-D
N-D
N-D
100 27
20
3
15
N-D
100 118
79 3598
100 450
100 N-D
47
100 N-D
92
92
10
I 1000
L 1000
DIGESTED
SLUDGE
1
N-D
124
2
117
N-D
4
N-D
5
40
13
N-D
6
10
32
4170
152
N-D
48
N-D
102
102
9
L 1000
L 1000
POLLUTANTS NOT LISTED WERE NEVER DETECTED
L-LESS THAN; N-D NOT DETECTED;
PRELIMINARY DATA ONLY — TO BE VERIFIED
(Continued)
-------
TABLE 6
(Continued)
PLANT 5
FRACTION
METALS
NON-CONV. METALS
PARAMETER
ANTIMONY
ARSENIC
BERYLLIUM
CADMIUM
CHROMIUM
COPPER
CYANIDE
LEAD
NICKEL
SELENIUM
SILVER
ZINC
ALUMINUM
BARIUM
CALCIUM
IRON
MAGNESIUM
MANGANESE
SODIUM
UNITS
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
MG/L
UG/L
MG/L
UG/L
MG/L
INFLUENT
L 50
L 50
1
6
102
70
12
67
12
L 50
23
248
817
101
74
1192
28
234
89
FINAL (
EFFLUENT
L 50
L 50
L 2
1
35
31
5
4
L 10
L 50
2
66
155
54
70
274
27
204
87
PERCENT
REMOVAL
100
83
66
56
58
94
100
91
73
81
47
5
77
4
13
2
PRIMARY
SLUDGE
91
78
6
390
8317
3000
221
8967
1077
53
1103
23833
NOT RUN
NOT RUN
NOT RUN
NOT RUN
NOT RUN
NOT RUN
NOT RUN '
DIGESTED
SLUDGE
50
69
6
310
7767
2767
28
9167
1240
41
800
24167
NOT RUN
NOT RUN
NOT RUN
NOT RUN
NOT RUN
NOT RUN
NOT RUN
POLLUTANTS NOT LISTED WERE NEVER DETECTED
L-LESS THAN; N-D NOT DETECTED;
PRELIMINARY DATA ONLY — TO BE VERIFIED
-------
TABLE 7 SUMMARY OF ANALYTICAL DATA
PLANT
FRACTION
CONVENTIONALS
NON-CONVENTIONALS
PARAMETER
BOD
TOTAL SUSP. SOLIDS
COD
OIL & GREASE
TOTAL PHENOLS
TOTAL SOLIDS
TOTAL DISS. SOLIDS
SETTLEABLE SOLIDS
TOTAL VOLATILE SOLIDS
VOLATILE DISS. SOLIDS
TOTAL VOL. SUS. SOLIDS
AMMONIA NITROGEN
TOC
BENZENE
CARBON TETRACHLOR1DE
CHLOROBENZENE
1,2-DICHLOROETHANE
1,1,1-TRICHLOROETI1ANE
1,1-DICHLOROETHANE
1,1,2-TRICHLOROETHANE
1,1,2,2-TETRACHLOROETHANE
CHLOROETHANE
CHLOROFORM
1,1-DICHLOROETHYLENE
1,2-TRANS-DICHLOROETHYLENE
ETHYLBENZENE
METHYLENE CHLORIDE
POLLUTANTS NOT LISTED WERE NEVER DETECTED
L-LESS THAN; N-D NOT DETECTED;
'PRELIMINARY DATA ONLY -- TO BE VERIFIED
VOLATILES
UNITS
MG/L
MG/L
MG/L
MG/L
UG/L
MG/L
MG/L
ML/L
MG/L
MG/L
MG/L
MG/L
MG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
INFLUENT
263
632
904
54
309
1370
678
493
678
161
530
20
391
1
L 2
L 1
11
417
8
1
L 1
L 15
6
43
35
1
32
FINAL
EFFLUENT
18
27
131
2
38
683
646
17
132
117
18
12
40
0
1 2
L 1
1
47
1
I 2
1 1
L 15
3
L 1
8
L 1
18
PERCENT
REMOVAL
93
96
86
96
88
50
5
97
81
27
97
40
90
100
91
89
88
100
50
100
77
100
44
PRIMARY
SLUDGE
18857
51342
55386
4988
4672
53717
4618
1825
4] 398
382
41017
82
24008
12
10
0
N-D
33
212
N-D
N-D
167
N-D
;N-D
'878
317
64
DIGESTED
SLUDGE
16856
47758
51787
4948
7420
49232
1140
1775
37662
445
37250
585
25625
11
N-D
0
N-D
N-D
N-D
N-D
1
1800
N-D
N-D
90
392
28
(Continued)
-------
TABLE 7 (Continued)
PLANT
FRACTION
VOLATILES
ACID EXTRACT
BASE-NEUTRALS
PARAMETER
METHYL CHLORIDE
DICHLOROBROMOMETHANE
TRICHLOROFLUOROMETHANE
TETRACHLOROETHYLENE
TOLUENE
TRICHLOROETHYLENE
VINYL CHLORIDE
PARACHLOROMETA CRESOL
2,4-DICHLOROPHENOL
PENTACHLOROPHENOL
PHENOL
ACENAPHTHENE
1,3-DICHLOROBENZENE
1,4-DICHLOROBENZENE
2,4-DINITROTOLUENE
NAPHTHALENE
BIS(2-ETHYLHEXYL) PHTHALATE
BUTYL BENZYL PHTHALATE
DI-N-BUTYL PHTHALATE
DIETHYL PHTHALATE
1,2-BENZANTHRACENE
CHRYSENE
ANTHRACENE
1,12-BENZOPERYLENE
FLUORENE
PHENANTHRENE
UNITS
INFLUENT
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
33
1
6
9
191
487
1698
9
1
15
1
1
3
1
1
1
64
L 5
38
15
I 5
1 5
52
6
1 5
52
L
I
L
L
L
FINAL
EFFLUENT
34
0
6
0
20
64
101
1
1
1
0
1
1
1
1
2
9
0
11
2
1
1
11
1
0
11
PERCENT
REMOVAL
100
100
100
90
87
94
89
100
93
100
100
100
100
86
71
87
79
83
79
PRIMARY
SLUDGE
N-D
N-D
N-D
58
1642
30
33167
N-D
N-D
N-D
882
N-D
N-D
N-D.
N-D
N-D
5200
1500
483
N-D
565
565
1505
N-D
N-D
1505
DIGESTED
SLUDGE
N-D
N-D
N-D
52
423
4
33800
N-D
N-D
N-D
2000
N-D
N-D
N-D
N-D
N-D
4086
N-D
N-D
N-D
124
124
994
N-D
N-D
994
POLLUTANTS NOT LISTED WERE NEVER DETECTED
L-LESS THAN; N-D NOT DETECTED;
PRELIMINARY DATA ONLY — TO BE VERIFIED
{Continued)
-------
TABLE 7 (Continued)
PLANT 6 '
FRACTION
METALS
NON-CON V. METALS
PARAMETER
ANTIMONY
ARSENIC
BERYLLIUM
CADMIUM
CHROMIUM
COPPER
CYANIDE
LEAD
MERCURY
NICKEL
SELENIUM
SILVER
ZINC
ALUMINUM
BARIUM
CALCIUM
IRON
MAGNESIUM
MANGANESE
SODIUM
UNITS
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
NG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
MG/L
UG/L
MG/L
UG/L
MG/L
INFLUENT
L 50
L 50
L 2
1076
1390
760
99
199
3233
701
L 50
15
4935
2380
302
56
7363
15
285
141
FINAL
EFFLUENT
L 50
L 50
L 2
65
62
47
389
18
200
294
L 50
3
475
134
31
46
421
13
151
135
PERCENT
REMOVAL
94
96
94
91
94
50
80
90
94
90
18
94
13
47
4
PRIMARY
SLUDGE
393
310
11
82500
74333
51333
22123
14767
602
17000
162
823
386667
NOT RUN
NOT RUN
NOT RUN
NOT RUN
NOT RUN '
NOT RUN
NOT RUN
DIGESTED
SLUDGE
350
212
9
79833
73833
46000
17597
7617
487
17500
152
802
365000
NOT RUN
NOT RUN
NOT RUN
NOT RUN
NOT RUN
NOT RUN
NOT RUN
POLLUTANTS NOT LISTED WERE NEVER DETECTED
L-LESS THAN: N-D NOT DETECTED:
PRELIMINARY DATA ONLY TO BE VERIFIED
-------
TABLE 8 SUMMARY OF ANALYTICAL DATA
PLANT 7
FRACTION
CONVENTIONALS
NON-CONVENTIONALS
Oo
VOLATILES
PARAMETER
BOD
TOTAL SUSP. SOLIDS
COD
OIL & GREASE
TOTAL PHENOLS
TOTAL SOLIDS
TOTAL DISS. SOLIDS
SETTLEABLE SOLIDS
TOTAL VOLATILE SOLIDS
VOLATILE DISS. SOLIDS
TOTAL VOL. SUS. SOLIDS
AMMONIA NITROGEN
TOC
BENZENE
CHLOROBENZENE
1,1,1-TRICHLOROETHANE
1,1-DICHLOROETHANE
1,1,2,2-TETRACHLOROETHANE
CHLOROFORM
1,2-TRANS_DICHLOROETHYLENE
1,2-DICHLOROPROPANE
1,3-DICHLOROPROPYLENE
ETHYLBENZENE
METHYLENE CHLORIDE
DICHLORODIFLUOROMETHANE
TETRACHLOROETHYLENE
EFFLUENT PCNT
UNITS
MG/L
MG/L
MG/L
MG/L
UG/L
MG/L
MG/L
ML/L
MG/L
MG/L
MG/L
MG/L
MG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
INFLUENT
169
135
328
41
55
862
718
3
329
225
105
13
65
1
L 5
47
1
L 5
5
2
L 5
L 5
22
36
L 5
15
L
L
L
L
L
1
L
L
L
PRE CL.
69
18
97
9
8
849
831
1
204
271
14
14
24
5
5
1
5
5
1
3
5
5
5
23
5
3
REM.
83
87
70
78
85
2
100
14
87
63
100
85
100
80
100
36
80
COMBINED
SLUDGE
27404
35057
52081
7983
1133
41248
4262
670
27934
2243
22103
257
9050
95
6
N-D
352
26
7
1517
L N-D
N-D
2100 '
8
32
1
HEAT HEAT
TREATED TREATMENT
SLUDGE
29013
26313
57922
9608
3512
34023
9578
343
23131
7581
15217
516
8433
.507
1
N-D
N-D
L N-D
N-D
283
8
55
460
1
N-D
15
DECANT
13964
2077
20110
533
4122
14116
11239
33
11496
9881
1615
433
8767
22
0
L 5
L 5
L 5
L 5
9
I 5
I 5
18
38
L 5
L 5
POLLUTANTS NOT LISTED WERE NEVER DETECTED
L-LESS THAN: N-D NOT DETECTED:
PRELIMINARY DATA ONLY TO BE VERIFIED
(Continued)
-------
TABLE 8 (Continued)
FRACTION
ACID EXTRACT
BASE-NEUTRALS
-F-
UJ
00
PESTICIDES
PLANT 7
PARAMETER UNITS INFLUENT
PENTACHLOROPHENOL
PHENOL
1,2-DICHLOROBENZENE
1,3-DICHLOROBENZENE
1,4-DICHLOROBENZENE
FLUORANTHENE
NAPHTHALENE
BIS(2-ETHYLHEXYL) PHTHALATE
BUTYL BENZYL PHTHALATE
DI-N-BUTYL PHTHALATE
DIETHYL PHTHALATE
1,2-BENZANTHRACENE
CHRYSENE
ANTHRACENE
PHENANTHRENE
PYRENE
HEPTACHLOR NG/L 417
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
L
I
L
L
L
L
L
L
L
27
9
3
11
11
5
8
197
7
3
7
5
5
11
11
5
POLLUTANTS NOT LISTED WERE NEVER DETECTED
L-LESS THAN: N-D NOT DETECTED
PRELIMINARY DATA ONLY TO BE VERIFIED
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
EFFLUENT
PRE CL.
250
300
11
11
11
11
11
90
11
11
11
5
5
11
11
5
1000
PCNT
REM.
100
100
100
54
100
100
100
100
COMBINED
SLUDGE
1000
173
233
35
28
143
147
11257
1162
318
N-D
153
153
827
827
160
HEAT
TREATED
SLUDGE
N-D
1717
50
N-D
10
13
16
10117
735
265
N-D
J25
25
407
407
14
L
L
L
L
L
L
L
L
L
L
L
L
HEAT
TREATMENT
DECANT
250
907
17
100
100
50
2
1498
100
100
100
50
50
100
100
50
L 1000
L 1000
333
-------
TABLE 8 (Continued)
PLANT 7
FRACTION
PESTICIDES
METALS
PARAMETER
HEPTACHLOR EPOXIDE
GAMMA-BHC
DELTA-BHC
ANTIMONY
ARSENIC
BERYLLIUM
CADMIUM
CHROMIUM
COPPER
CYANIDE
LEAD
MERCURY
NICKEL
SELENIUM
SILVER
THALLIUM
ZINC
ALUMINUM
BARIUM
BORON
CALCIUM
COBALT
IRON
MAGNESIUM
MANGANESE
MOLYBDENUM
SODIUM
TIN
POLLUTANTS NOT LISTED WERE NEVER DETECTED
L-LESS THAN: N-D NOT DETECTED:
PRELIMINARY DATA ONLY TO BE VERIFIED
NON-CONV. METALS
UNITS
NG/L
NG/L
NG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
NG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
MG/L
UG/L
UG/L
MG/L
UG/L
UG/L
MG/L
UG/L
INFLUENT
83
500
83
6
L 3
0
5
289
223
42
72
1000
345
L 3
5
L 25
619
464
84
759
74
11
3463
20
62
17
131
23
EFFLUENT
PRE CL.
83
500
L 1000
3
L 3
3
5
52
39
24
47
1000
325
L 3
1
I 25
108
87
23
787
72
10
407
19
60
15
130
13
PCNT
REM.
100
50
82
83
43
35
6
80
83
81
73
3
9
88
5
3
12
1
43
COMBINED
SLUDGE
L 1000
1 1000
L 1000
1403
332
L 10
498
72667
45833
2503
44167
205000
2733
153
177
L 10
120333
NOT RUN
NOT RUN
NOT RUN
NOT RUN
NOT RUN
NOT RUN
NOT RUN
NOT RUN
NOT RUN
NOT RUN
NOT RUN
HEAT
TREATED
SLUDGE
L 1000
L 1000
L 1000 L
1047
207
L 10
313
56000
35333
278
6133
140500
20667
93
185
L 10
98833
NOT RUN
NOT RUN
NOT RUN
NOT RUN
NOT RUN
NOT RUN
NOT RUN
NOT RUN
NOT RUN
NOT RUN
NOT RUN
HEAT
TREATMENT
DECANT
83
167
1000
54
56
1
139
9569
5701
49
1701
1000
9888
8
27
52
32602
15523
935
1055
308
190
46081
70
1104
154
164
391
(Continued)
-------
TABLE 8 (Continued)
PLANT 7
FRACTION
PARAMETER
UNITS
INFLUENT
EFFLUENT
PRE CL.
PCNT
REM.
COMBINED
SLUDGE
HEAT
TREATED
SLUDGE
HEAT
TREATMENT
DECANT
TITANIUM
VANADIUM
YTTRIUM
UG/L
UG/L
UG/L
7
142
3
4
132
3
43
7
NOT RUN
NOT RUN
NOT RUN
NOT RUN
NOT RUN
NOT RUN
171
662
18
-P-
O
POLLUTANTS NOT LISTED WERE NEVER DETECTED
L-LESS THAN: N-D NOT DETECTED:
PRELIMINARY DATA ONLY TO BE VERIFIED
-------
TABLE 9 SUMMARY OF ANALYTICAL DATA
PLANT 8
FRACTION
CONVENTIONALS
NON-CONVENTIONALS
VOLATILES
ACID EXTRACT
PARAMETER
BOD
TOTAL SUSP.
COD
OIL & GREASE
SOLIDS
TOTAL PHENOLS
TOTAL SOLIDS
TOTAL DISS. SOLIDS
SETTLEABLE SOLIDS
TOTAL VOLATILE SOLIDS
VOLATILE DISS. SOLIDS
TOTAL VOL. SUS. SOLIDS
AMMONIA NITROGEN
TOG
BENZENE
1,1,1-TRICHLOROETHANE
1,1-DICHLOROETHANE
CHLOROFORM
1,2-DICHLOROPROPANE
ETHYLBENZENE
METHYLENE CHLORIDE
TETRACHLOROETHYLENE
TOLUENE
TRICHLOROETHYLENE
2,4-DICHLOROPHENOL
PENTACHLOROPHENOL
PHENOL
UNITS
MG/L
MG/L
MG/L
MG/L
UG/L
MG/L
MG/L
ML/L
MG/L
MG/L
MG/L
MG/L
MG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
INFLUENT
238
205
544
115
72
928
723
4
453
309
144
16
119
2
33
1
8
1
15
14
26
229
30
0
18
9
FINAL
EFFLUENT
42
69
211
14
13
746
677
2
321
268
53
20
52
7
L 2
L 1
11
L 1
2
7
1
288
0
0
17
1
PERCENT
REMOVAL
82
66
61
88
82
20
6
50
29
13
63
56
100
100
100
87
50
96
100
6
89
POLLUTANTS NOT LISTED WERE NEVER DETECTED
L-LESS THAN: N-D NOT DETECTED:
PRELIMINARY DATA ONLY TO BE VERIFIED
(Continued)
441
-------
TABLE 9 (Continued)
PLANT 8
FRACTION
BASE-NEUTRALS
METALS
NON-CONV. METALS
PARAMETER
1,4-DICHLOROBENZENE
FLUORANTHENE
NAPTHALENE
BIS(2-ETHLHEXYL) PHTHALATE
BUTYL BENZYL PHTHALATE
DI-N-BUTYL PHTHALATE
DIETHYL PHTHALATE
ANTHRACENE
PHENANTHRENE
CHROMIUM
COPPER
CYANIDE
LEAD
MERCURY
NICKEL
SELENIUM
SILVER
ZINC
ALUMINUM
BARIUM
CALCIUM
IRON
MAGNESIUM
MANGANESE
SODIUM
UNITS
INFLUENT
UG/L
UG/L
DG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
NG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
MG/L
UG/L
MG/L
UG/L
MG/L
1
1
12
33
50
2
2
2
2
256
337
11
329
350
427
L 50
13
1722
1278
537
54
5460
15
190
140
L
L
L
L
L
L
L
FINAL
EFFLUENT
2
3
1
/
4
4
4
3
3
35
108
4
85
200
236
26
1
500
474
185
59
1814
15
152
139
PERCENT
REMOVAL
100
100
100
79
92
100
100
100
67
68
64
74
100
45
92
71
63
66
67
20
1
POLLUTANTS NOT LISTED WERE NEVER DETECTED
L-LESS THAN: N-D NOT DETECTED
PRELIMINARY DATA ONLY TO BE VERIFIED
442
-------
TABLE 10 SUMMARY OF ANALYTICAL DATA
PLANT 8
FRACTION
CONVENTIONALS
NON-CONVENTIONALS
PARAMETER
BOD
TOTAL SUSP. SOLIDS
COD
OIL & GREASE
TOTAL PHENOLS
TOTAL SOLIDS
TOTAL DISS. SOLIDS
SETTLEABLE SOLIDS
TOTAL VOLATILE SOLIDS
VOLATILE DISS. SOLIDS
TOTAL VOL. SUS. SOLIDS
AMMONIA NITROGEN
TOC
BENZENE
CARBON TETRACHLORIDE
CHLOROBENZENE
1,1,2-TRICHLOROETHANE
1,1,2,2-TETRACHLOROETHANE
CHLOROFORM
ETHYLBENZENE
METHYLENE CHLORIDE
METHYL CHLORIDE
TETRACHLOROETHYLENE
TOLUENE
TRICHLOROETHYLENE
POLLUTANTS NOT LISTED WERE NEVER DETECTED
L-LESS THAN: N-D NOT DETECTED:
PRELIMINARY DATA ONLY TO BE VERIFIED
VOLATILES
UNITS
MG/L
MG/L
MG/L
MG/L
UG/L
MG/L
MG/L
ML/L
MG/L
MG/L
MG/L
MG/L
MG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
INFLUENT
113
149
267
36
67
455
234
9
190
54
131
10
86
1
1
L 5
23
1
4
1
5
2
4
8
33
FINAL
EFFLUENT
5
14
36
6
7
292
235
L 1
66
50
9
3
12
4
L 5
1
1
L 5
2
1
L 5
2
0
0
L 5
PERCENT
REMOVAL
96
91
87
83
90
36
100
65
7
93
70
86
100
96
100
50
100
100
100
100
(Continued)
443
-------
TABLE 10 (Continued)
PLANT 8
FRACTION
ACID EXTRACT
BASE-NEUTRALS
METALS
PARAMETER
PARACHLOROMETA CRESOL
4,6-DINITRO-O-CRESOL
PHENOL
BIS(2-ETHYLHEXYL) PHTHALATE
DI-N-BUTYL PHTHALATE
DIETHYL PHTHALATE
ANTIMONY
ARSENIC
CADMIUM
CHROMIUM
COPPER
CYANIDE
LEAD
NICKEL
SELENIUM
SILVER
ZINC
ALUMINUM
BARIUM
BORON
CALCIUM
IRON
MAGNESIUM
MANGANESE
HOLYBDENUM
SODIUM
TIN
TITANIUM
VANADIUM
POLLUTANTS NOT LISTED WERE NEVER DETECTED
L-LESS THAN: N-D NOT DETECTED:
PRELIMINARY DATA ONLY TO BE VERIFIED
UNITS
INFLUENT
NON-CONV. METALS
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UC/L
UC/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
MG/L
UG/L
MG/L
UG/L
UG/L
MG/L
UG/L
UG/L
UG/L
2
L 50
2
5
13
11
0
2
3
55
70
82
91
38
2
11
160
577
115
145
29
1505
7
169
L 36
46
20
27
4
L
L
L
L
FINAL
EFFLUENT
50
0
60
20
16
2
0
2
2
3
26
27
17
25
2
1
57
98
34
131
27
372
7
91
7
26
6
2
PERCENT
REMOVAL
100
100
100
82
33
95
63
67
81
34
91
64
83
70
10
7
75
46
100
78
50
-------
POTW's with flows above 5 MGD, no smaller plants will be sampled, with a full
spectrum of larger plants included in the project. With regard to industrial
flow, POTW's ranging from zero to more than 50 percent industrial contribu-
tion will be covered. Similarly, it is anticipated that all of the 34 in-
dustrial groups currently under review by the EPA Effluent Guidelines Divi-
sion that discharge to POTW's will be covered by the study. Few plants al-
ways meet the 30/30 BOD, TSS secondary treatment requirements, but POTW's
are only selected if their operation is found to be reasonably good. Final-
ly, POTW's will be selected from each EPA region. The number of plants
selected will be in proportion to the total number of POTW's in that region.
As a result, the more densely populated regions will have more POTW's
included in the 40 plant study.
The nine plants covered in this paper are all activated sludge plants.
As a result, no comparisons between treatment processes can be drawn. Never-
theless, activated sludge is a prevalent treatment process, making this par-
tial data valuable.
Data Summary
Tables 2 through 10 present summaries of the analytical data available
for the nine POTW's covered in this paper. The data base is complete for
the first seven plants. At the time of this writing, no sludge data had been
received for Plant 8 and Plant 9. All concentrations shown in the tables are
for averages of the values obtained during the week of sampling at each
plant. Similarly, the percent "removals" presented were calculated using
the weekly averages.
Impact of Industrial Flow
One of the objectives of the work was to determine the impact of indus-
trial contributions on the concentrations of priority pollutants measured
at the influent to the POTW. Table 11 presents a summary of linear regres-
sion calculations to determine if there is a correlation. Since the
current data base is somewhat limited with only nine plants' data included,
a high degree of variability could be expected. To decrease the expected
variability, instead of calculating the regression for each individual prior-
ity pollutant, regressions for the sum of various priority pollutant frac-
tions versus percent industrial flow were calculated. As can be seen from
the table, all major fractions, metals, organics, volatiles and base-
neutrals, statistically increased as percent industrial flow increased. That
is, for each correlation the slope of the least squares fit was always
positive. For metals, organics and volatiles, the slopes were relatively
steep. The base-neutrals fit was not as good or steep with a slope of only
0.25, but the tendency was still for increasing influent concentration with
increasing industrial input.
445
-------
The quality of the least squares fit is described by the R^ value shown
on Table 11. The higher R2 is, up to a maximum of 1.00, the better the fit.
Although there are no R2 values very close to unity, the R^ values obtained
are respectable considering the limited nature of the data base with only
nine data points. It is expected that later evaluations of this kind using
the full 40 plant data base that will be generated will produce better
correlations. Nevertheless, the tendency for higher influent priority
pollutant concentrations with increasing industrial flow appears to be prev-
alent. It should also be noted that, although not appropriate at this stage,
multiple regression will be attempted on the full data base. This method is
expected to provide a better description of this phenomena.
TABLE 11. LINEAR REGRESSION - INFLUENT PRIORITY POLLUTANT CONCENTRATION
Priority Pollutant
Fraction Slope R2 n
Metals
Organics
Volatiles
Base-Neutrals
29.9
2.11
3.16
0.25
0.53
0.32
0.26
0.04
9
9
9
9
Effect of POTW Operations on Priority Pollutant Removal and Treatment
POTW's are generally designed to reduce the concentrations of conven-
tional pollutant parameters such as BOD, TSS and fecal coliform. Removal or
treatment of other pollutants is often only incidental, by virtue of the fact
that POTW's are designed to treat only a few compatible pollutants. As a
result, the common assumption is that since the priority pollutants are
generally incompatible with standard POTW unit operation, no appreciable re-
duction of these pollutants takes place. The nine plant POTW data base con-
tradicts this assumption. In fact, for many of the priority pollutants, ex-
cellent removals were observed considering there was no deliberate opera-
tional effort made to remove these pollutants.
Figures 1 and 2 illustrate the cumulative removals and effluent con-
centrations observed for metals, organics and the three organic analytical
fractions observed in the nine plant data base. (Note: Acid extract param-
eters were observed at only seven plants.) The graphs are cumulative
distributors which show the percent of plants whose removal or effluent were
greater than or equal to a particular value. For the organics, at least 80
percent of the plants obtained 80 percent or better removals. For the
metals, 80 percent of the plants achieved roughly 60 percent removal.
Consistent Removal
The value of incidental removal of industrial priority pollutants in
POTW's is that this removal may be applied to modifications of Federal
categorical pretreatment standards applicable to an industrial subcategory.
Credits of this sort derived from the kind of incidental removal described
here may be applied to a contributing industry's discharge if certain
criteria, as set forth in the General Pretreatment Regulations for Existing
446
-------
FIGURE 1 '
CUMULATIVE DISTRIBUTION CURVES
Al
Pi
H
a
w
0
Pi
w
p-l
100
80 -
60
40 H
20
ORGANICS
METALS
N = 9
0 20 40 60 80 100
100
80-
0 20 40 60 80 100
Al
H 60
23 e
pi] ••— ^
O
H
H
-------
FIGURE 2
CUMULATIVE DISTRIBUTION CURVES
Al
W
U
Pd
w
PH
ACIDS
100-
.. N = 7
> 80-
o
S
w 60
40-
20-
OH—i—i—'—i—i—i—i—\—i-
0 20 40 60 80 100
BASE-NEUTRALS
100-
80-
60-
40-
20-
= 9
T11|I|i|T-
0 20 40 60 80 100
100
80-
60-
40
20 -
VOLATILES
1 |
0 20
N = 9
-I . | . | i-
40 60 80 100
Al
H 60
a s
[V) *~~S
I—I P"H
PM O
W
U
S3
O
O
6-
4-
2-
N = 7
0 20 40 60 80 100
0 20 40 60 80 100
% OF PLANTS
40'
32-
24 -
16
N = 9
-I 1 1 p- 4—r 1 , f=
0 20 40 60 80 100
-------
and New Sources of Pollution (40 CFR 403), are met. Beyond administrative
requirements, such as receipt of approval to revise limits, having an approv-
ed pretreatment program and considerations regarding control of bypass events,
the POTW must develop technical information in two general areas.
First, the POTW must show that the treatment plant achieves "consistent
removal" of the toxic pollutant in question. In the revisions to 40 CFR 403
(October 29, 1979) EPA defines consistent removal as "the average of the
lowest 50 percent of the removals measured." At least eight influent and
eight effluent samples, seasonally spaced must be taken to establish the
removal efficiency. More samples are preferred, but when between eight and
twelve are taken, the average of the' lowest six removals may be used in the
determination of "consistent removal."
The POTW must also determine if the pollutant in question, after re-
vision of the categorized standard, will interfere with plant operations in
terms of excursions from NPDES permit requirements and disruption of sludge
disposal pathways. The regulations state that the pollutant must not
"cause or significantly contribute" to a violation of the NPDES permit for
credits to be allowed. Further, the increased toxic contribution to the
POTW must not cause sludge quality to exceed that required by existing
regulatory requirements.
Table 12 summarizes calculated approximate "consistent removals" ob-
served in the nine plant data base for selected priority pollutants. The
parameters shown on the table are those pollutants for which EPA has promul-
gated categorical pretreatment standards in four industrial categories. The
categories include Electroplating, Textiles, Petroleum
and Leather Tanning. The "consistent removals" were calculated by averaging
the lowest four removals found during the six or seven days of sampling at
each plant. The table shows that considerable removal credits may be ob-
tainable if all additional technical and administrative requirements can be
met.
TABLE 12. APPROXIMATE "CONSISTENT REMOVALS" BASED ON NINE PLANT DATA BASE
Priority Pollutant
Copper
Nickel
Chromium
Zinc
Lead
Cadmium
Silver
Cyanide
Percent Removal
42
2
45
38
0
0
0
0
to 91
to 41
to 94
to 81
to 82
to 92
to 80
to 74
449
-------
Concentration of Priority Pollutants in the Sludge
One of the technical factors that might preclude the use of incidental
removal for revision of Categorical Standards is the impact of priority
pollutant removal on sludge quality. To provide some perspective on the
relative importance of sludge contamination with regard to the removal of
certain priority pollutant groups, Table 13 has been developed.
TABLE 13. AVERAGE CONCENTRATION FACTORS
Fraction Primary Sludge Combined Sludge
Volatiles 7 30
Acid Insufficient Data
Base-Neutral 115 105
Metals 160 175
Table 13 presents a summary of the average concentration factors (de^-
fined as the sludge concentration divided by the influent concentration) for
each priority pollutant fraction at both plants where the primary sludge was
sampled (Plants 1, 5 and 6) and plants where a combined sludge stream was
sampled (Plants 2, 3, 4 and 7), The averages were computed using only
parameters which were consistently measured above their detection limit.
This procedure eliminated several instances where parameters were not mea^
sured in the influent but were found in the sludges, which would have re-
sulted in infinite concentration factors. The number of data points included
is consequently small, and a wide variation in factors was encountered.
Nevertheless, several trends appeared clear.
Volatile priority pollutants which are primarily refractory had the
lowest concentration factors, consistent with the hypothesis that airstrip--
ping is a principal removal mechanism for them. Base-neutral priority
pollutants showed much higher concentration factors. For example, bis(2-
ethyl-hexyl)phthalate which occurred at the highest levels across most
plants showed concentration factors ranging from 7 to 272, with an average of
111 and a median of 85. Metal priority pollutants had the highest concen^-
tration factors, averaging 160 in primary sludges and 175 in combined
sludges.
Mass Balance
To confirm the valudity of the data base, mass balances were calculated.
Table 14 summarizes the masses of priority pollutants in the influent and
effluent and sludge streams at each POTW. For the most part, the influent
and "total out" columns are within the same order of magnitude, and mass
balances for conventional pollutant parameters show good agreement.
Several trends are indicated by the data. Volatile priority pollutants
showed a median loss from the influent to the exiting streams of 72 percent,
with a range of 25 to 87 percent. Base-neutral organics showed a median
loss of 37 percent with a range of 0 to 78 percent. Metals in the "total
450
-------
TABLE 14 MASS BALANCE (1)
Plant Fraction
No. (Ib/d) Influent
1 Organics (3) 252
Volatiles 133
Acid Extraction 14
Base-neutrals 55
Metals 820
2 Organics 6.8
Volatiles 3.2
Acid" Extraction .3
Base-neutrals 3.3
Metals 36
3 Organics 27
Volatiles 19
Acid Extraction 2
Base-neutrals 6.2
Metals 79
4 Organics 1323
Volatiles 1109
Acid Extraction 15
Base-neutrals 199
Metals 575
Pesticides . 3
5 Organics 179
Volatiles 171
Acid Extraction .4
Base-neutrals 8
Metals 99
Pesticides 0
6 Organics 191
Volatiles 175
Acid Extraction 1.6
Base-neutrals 14
Metals 540
7 Organics 160
Volatiles 65
Acid Extraction 3.7
Base-neutrals 91
Metals 649
Pesticides .6
(1) Fraction masses to nearest pound
All metals and organics (total)
(2) Combined sludge for Plants 4, 5
Plant 7 is heat treated combined
Total
Out
122
51
20
51
1480
6.5
2.4
1.5
2.6
33
8
5
2
1.4
49
376
315
1
60
914
.2
106
98
.3
8
92
.2
27
23
.5
4
181
83
23
2.9
57
610
.3
Final Primary Secondary
Effluent Sludge Sludge
38 28 8
41 5 5
17 1 2
30 22 1
160 760 560
5.2
1.9
1.5
1.3
17
5
4
0
.9
25
302
• 282
0
20
241
.2
97
96
.1
1
26
.2
19
16
.3
3
80
54
17
0
37
245
.3
Combined.
Sludge (2)
2.1
.8
.1
1.2
16
4
1
2
.6
23
73
34
1
33
673
0
3
1
.3
7
66
0
8
7
.3
1
102
31
7
2.9
21
365
0
, except where less than 1 pound, inwhich case to .1 pound.
to nearest pound.
and 6 is
sludee.
digested combined sludge. Combined
sludge for
(3) Organics is a summation of volatiles, acid extractables, and base-neutrals.
451
-------
out" had a median value 7 percent lower than the Influent, ranging from an
80 percent increase to a 65 percent decrease.
The mass of organic priority pollutants was approximately one-third or
less than the mass of metallic priority pollutants at Plants 1, 2, 3, 6 and
7. However, at Plants 4 and 5, the relationship was reversed, with organic
pollutants having roughly twice the mass of metallic priority pollutants
present. At both of these plants the volatile pollutant fraction accounted
for most of the organic pollutant mass measured.
SUMMARY AND CONCLUSIONS
During 1981 the full 40 POTW data base will be established. It is
anticipated that this data base will be large enough to allow development
of firm conclusions regarding the fate of toxic pollutants in POTW's. How-
ever, at this time, it can be preliminarily concluded that significant in-
cidental priority pollutant removal does take plant in POTW's. Further, it
is clear that influent toxic pollutant concentration increases as the amount
of industrial contribution increases. The full data base should provide an
opportunity to better describe removals and toxic pollutant incidence as well
as other specific phenomena. In the interim, the data presented here should
provide a basis for understanding the behavior of priority pollutants in
POTW's.
ACKNOWLEDGMENTS
The authors would like to acknowledge the efforts of the following Burns
and Roe employees who aided in the preparation of this paper: F. Thompson,
H. Chen, M. Klingenstein.
452
-------
PB83-142422
BEHAVIOR OF SELECTED TOXIC SUBSTANCES
IN WASTEWATER COLLECTION AND TREATMENT SYSTEMS
A. C. Petrasek, Jr., Ph.D., P.E.
Chief, MERL Pilot Projects
Test and Evaluation Facility
U.S. Environmental Protection Agency
Cincinnati, Ohio
INTRODUCTION
Section 307 of Public Law 92-500 requires the Environmental Protection
Agency to identify toxic substances and to promulgate regulations control-
ling the discharge of those materials from point sources. The original list
of 65 toxic substances evolved from the NRDC Consent Decree (NRDC vs. Train),
and has subsequently been expanded to include more than 129 specific toxics.
The objective of this research effort is to provide information about the
behavior of some of the toxic substances in conventional water pollution con-
trol systems.
For the purpose of research efficiency, the organic chemicals on the
priority pollutant list have been segregated into two general categories;
those chemicals which are volatile, which implies stripping may be a signi-
ficant mechanism of removal, and those organic compounds which are semivola-
tile. The project discussed in this paper is studying the behavior of the
semivolatile organic priority pollutants and the heavy metals.
The basic approach in this project is to operate parallel sequences of
unit processes. One treatment train is operated as a control; the other
sequence has the organic compounds being studied added in a toluene solution.
The initial spiking provides a concentration of 50 micrograms/liter for most
of the organic compounds being studied. All process flows, sludges, and off-
gases are sampled so that the behavior of the spiked chemicals and indigenous
metals can be quantitated.
PILOT PLANT EQUIPMENT
The research apparatus being used in this project is installed at the
U.S. EPA's Test and Evaluation (T&E) Facility in Cincinnati, Ohio. The T&E
Facility is located on the site of the Metropolitan Sewer District's Mill
Creek Sewage Treatment Plant. All of the Mill Creek STP process flows and
sludges are pumped to the T&E Facility where they can be utilized as feed
streams for various experimental systems. All of the process flows generated
at the T&E Facility are returned to the headworks of the Mill Creek STP.
453
-------
The two existing treatment sequences have design flows of 1.5 gpm, and
a simplified schematic diagram is shown in Figure 1. Raw wastewater from
the Mill Creek STP is pumped at 300 gpm to the raw wastewater head tank in
the T&E Facility, from this point approximately 35 gpm is diverted to the
project site. The raw wastewater is first screened on a Bauer Hydrasieve to
remove large particulates that could clog process piping.
The screened raw wastewater is then pumped'to a manifold where the flow
is split into the 1.5 gpm treatment sequence influents. The spike solution
is added to the experimental train with a metering pump immediately after
the flow is split.
The sewer simulator consists of 84 feet of 3-inch steel pipe on a seven
percent grade, which provides a 4.5 foot per second velocity with the pipe
half-full at 50 gpm. A sump and recirculation pump provide a 73-minute de-
tention time at the design flow of 1.5 gpm.
The aerated grit chambers were designed to simulate the stripping asso-
ciated with the process. The units are stainless steel drums that provide
a theoretical residence time of 15 minutes and receive air flows of 25-30
scfh.
The primary clarifiers are 3-foot diameter stainless steel units with a
5-foot SWD. The clarifiers have a 45-degree cone on the bottom and sludge
collectors that operate at 5 rph. Design overflow rate and weir loading are
305 gpd/ft and 243 gpd/ft., respectively.
The activated sludge process consists of stainless steel aeration basins
and secondary clarifiers, which are identical to the primary clarifiers.
The design residence time in the 5 pass aeration basins is 7.5 hours. The
units are 2-ft. wide, 10-ft. long, and have a 4.5 ft. SWD, Typical air
flows are 20 scfm.
All process piping is either steel, cast iron, or stainless steel to
avoid any possibility of organic contamination. The feed and return sludge
pumps are Moyno progressive cavity with Buna-N stators and chromed rotors.
SYSTEM OPERATION
General
The data in Table 1 are a summary of six months of operation of the A
and B treatment sequences on the semivolatile priority pollutant research
project. When considered in terms of the more conventional water quality
parameters, the treatment has been excellent, more importantly the A and B
trains are providing almost identical results.
During this period the mean reductions observed for TSS, COD, and TOC
were 95, 89, and 89 percent, respectively. The average effluent TSS concen-
tration was 30 mg/1, which corresponded to a mean turbidity of 25 NTU.
454
-------
Raw Wastewater
T
R
E
A
T
M
E
N
T
S
E
Q
u
E
N
C
E
0
C
C
Spike Solution
Metering Pump
Supply Pump
Head Tank
Static Screen
1 Feed Pump
i Sewer f
Simulators
Aerated Grit Chambers
Primary Clarifiers
Aeration Basins
Figure
Secondary Clarifiers
Simplified Schematic Diagram:
Pollutant Project
T
R
E
A
T
M
E
N
T
S
E
Q
u
E
N
C
E
Nonvolatile Priority
455
-------
TABLE 1. SUMMARY OF CONVENTIONAL
TREATMENT SEQUENCES A & B
OCTOBER 1979 thru MARCH 1980
Parameter
TSS
COD
TOG
Total P
TKN
NH -N
N02 & N03-N
Total N
Alkalinity (as CaCO )
Turbidity (NTU)
Sequence
Influent
(mg/1)
A
607
741
214
9.0
40.6
21.0
0.1
40.7
-
-
B
576
748
210
8.6
39.5
21.2
0.1
39.6
-
-
Primary
Effluent
(mg/D
A
310
443
138
6.4
34.1
19.8
0.1
34.2
298
96
B
383
410
127
6.1
34.4
18.9
0.2
34.6
291
96
A.S.
Effluent
(mg/1)
A
30
86
23
3.1
11.4
6.5
5.2
16.6
203
25
B
31
83
24
3.1
8.5
4.4
5.8
14.3
180
25
Total
Removal
(percent)
A
95
88
89
66
72
69
-
59
-
-
B
95
89
89
64.
79
79
-
64
-
—
Ln
-------
Static Screen
The Hydrasieve effected a 57.5 percent reduction in TSS, which resulted
in a mean TSS concentration of 592 mg/1 in the screened product. The Hydra-
sieve has proved to be reasonably effective in preventing plugging of the
3/4-inch and 1-inch lines in the subsequent unit processes.
Sewer Simulators
No significant changes occurred in the conventional water quality param-
eters that can be attributed to this process, with the exception of ammonia
nitrogen. During the six-month period the mean concentration of ammonia
nitrogen decreased by 1.3 mg/1 in the A sequence and 2.2 mg/1 in the B se-
quence. This corresponds to a 9.4 percent reduction for the A train and a
10.4 percent decrease in the B system. The reductions can be attributed to
stripping in the simulated sewer.
Aerated Grit Chamber
As expected, the two aerated grit chambers did not make any significant
changes in the conventional water quality parameters during the first six
months of operation.
Primary Clarifiers
The primary clarifiers have provided good treatment during the first
six months of operation. Total suspended solids reductions averaged 53.2
percent for the A unit and 45.3 percent for the B system. COD reductions
for the A and B system averaged 51.2 and 51.4 percent, respectively; and
the mean TOG reductions were 48.1 for the A system and 49.2 percent for the
B primary clarifier. During this portion of the study the primary clarifier
effluent quality was as shown in Table 1.
Activated Sludge Processes
Both of the activated sludge processes provided good treatment during
the first six months. After initial start-up the processes were operated
in a nitrifying mode for three months. At that time it was decided that
non-nitrifying operation was more typical of municipal treatment plants, and
the processes were shifted to non-nitrifying operation. Both processes have
operated well on the relatively strong Mill Creek wastewater. Typical res-
piration rates in the mixed liquor range from 45 to 90 mg-hr/1.
INORGANIC WATER QUALITY
Combined municipal/industrial nonconsumptive water use increases the
pollutant load in Cincinnati rather substantially as the data in Table 2
indicate. The column headed Process Influent is the means of 15 weekly com-
posite samples of the screened raw wastewater entering the control sequence
(treatment sequence A). Data for the City of Cincinnati drinking water are
averages for calendar years 1974 through 1978, with the exception of certain
metals data which are averages for calendar year 1978.
457
-------
TABLE 2. INCREASE IN MEAN CONCENTRATIONS
DUE TO MUNICIPAL/INDUSTRIAL USE
Metal
*
As
A
Ag
Ca
A
Cd
Cr
Cu
Fe
Mg
Mn
Ni
Pb
Zn
TDS
S°4
Si02
Cl
F
Process 3
Influent
(mg/1)
< 20
<2.7
80
29.9
0.50
0.74
3.65
-
18.7
0.62
0.30
0.95
1.25
-
289
54
250
0.6
Cinti.
Drinking,
Water
(mg/l)
51
o.oo1
452
o.ooo1
0.002 l
-
0.302
O.I1
9.22
O.OO2
-
0.0061
-
251 2
83 2
4-7 2
28 2
0.302
Increase
(mg/l)
< 19.5
< 2.7
35
29.9
0.50
-
3.35
-
9.5
0.62
-
0.95
-
-
206
49+
222
0.28
* - micrograms/liter
1 - average for 1978
2 - average for 1974-1978
3 - average of 15 weekly composites
458
-------
The Si02 increase of 49 mg/1 is notable, as are the sulfate and chloride
increases of 206 mg/1 and 222 mg/1, respectively. Substantial increases in
Cd, Cr, Fe, Mg, Pb, Mn, and Zn are apparent. The Mill Creek interceptor,
which runs generally north up the Mill Creek valley, serves the preponderance
of the major industry in Cincinnati and the water quality data confirm that
fact.
Since November 1, 1979, twenty weekly compo'site samples were collected
for metals determinations. The sampling was performed on the control se-
quence A (unspiked), and all samples were acidified with two milliters of
concentrated nitric acid. The results obtained to date are presented in
Tables 3 through 11. The data for mercury and arsenic have not been pres-
ented because the metals concentrations were below the detection limit in
virtually all samples.
Silver
Silver was present at concentrations below the detection limit in a sub-
stantial number of samples at all sampling points; therefore, percent reduc-
tion data are of only limited utility. The data in Table 3 indicate the
primary clarifier was somewhat effective in reducing the silver concentration,
and that the activated sludge process had no measurable effect on the concen-
tration of silver.
Cadmium
Cadmium was only slightly reduced in concentration by the primary clari-
fier (26 percent); however, the activated sludge process removed over 87 per-
cent of the cadmium. Both the sewer simulator and aerated grit chamber had
no significant effect on Cd concentrations. Figure 2 shows the Cd concentra-
tions observed in the influent, primary clarifier effluent, and activated
sludge effluent.
Chromium
Neither the sewer simulator, aerated grit chamber, or primary clarifier
had any significant effect on the observed Cr concentrations. The activated
sludge process did reduce the mean Cr concentration by 0.34 mg/1, or 72 per-
cent. The Cr concentrations observed at selected sampling points are shown
in Figure 3.
Copper
The only unit process to significantly alter the observed Cu concentra-
tions was the activated sludge process. The observed mean decrease was 0.76
mg/1, or 92 percent. Figure 4 presents some of the Cu data, and there are
notable variations, particularly in the primary clarifier effluent. The high
values for the standard deviation and variance confirm that observation.
459
-------
TABLE 3. OBSERVED SILVER CONCENTRATIONS
WEEKLY COMPOSITE SAMPLES
NOV. 1, 1979 to MARCH 21, 1980
Sample
Location
Influent
Sewer Simulator
Effluent
Grit Chamber
Effluent
Primary Effluent
Activated Sludge
Effluent
Number of
Analyses
20
19
19
20
20
Arith.
Mean
<2.7
<2.6
<2.4
<1.5
<1.6
Std.
Deviation
2.296
1.894
2.090
0.889
0.754
Variance
5.010
3.402
4.138
0.750
0.540
TABLE 4. OBSERVED CADMIUM CONCENTRATIONS
WEEKLY COMPOSITE SAMPLES
NOV. 1, 1979 to MARCH 21, 1980
Sample
Location
Influent
Sewer Simulator
Effluent
Grit Chamber
Effluent
Primary Effluent
Activated Sludge
Effluent
Number of
Analyses
20
20
19
20
20
Arith.
Mean
29.9
22.7
28.4
21,0
2.7
Std.
Deviation
16.69
12.51
17.60
19.37
1.92
Variance
264.49
148.63
293.51
356.40
3.51
460
-------
TABLE 5. OBSERVED CHROMIUM CONCENTRATIONS
WEEKLY COMPOSITE SAMPLES
NOV. 1, 1979 to MARCH 21, 1980
j
1
Sample
Location
Influent
Sewer Simulator
Effluent
Grit Chamber '
Effluent
Primary Effluent
Activated Sludge
Effluent
Number of
Analyses
20
20
20
20
20
Arith.
Mean •
0.50
0.50
0.57
0.47
0.13
Std.
Deviation
0.423
0.285
0,374
0.353
0.143
Variance
0.170
0.077
0.133
0.119
0.019
TABLE 6. OBSERVED COPPER CONCENTRATIONS
WEEKLY COMPOSITE SAMPLES
NOV. 1, 1979 to MARCH 21, 1980
Sample
Location
Influent
Sewer Simulator
Effluent
Grit Chamber
Effluent
Primary Effluent
Activated Sludge
Effluent
Number of
Analyses
20
20
19
20
20
Arith.
Mean
0.74
0.76
0.88
0.86
0.10
Std.
Deviation
0.265
0.263
0.319
0.640
0.051
Variance
0.067
0.066
0.096
0.389
0.003
461
-------
TABLE 7. OBSERVED IRON CONCENTRATIONS
WEEKLY COMPOSITE SAMPLES
NOV. 1, 1979 to MARCH 21, 1980
Sample
Location
Influent
Sewer Simulator
Effluent
Grit Chamber
Effluent
Primary Effluent
Activated Sludge
Effluent
Number of
Analyses
20
20
19
20
20
Arith.
Mean
3.65
4.' 11
4.97
2.42
0.94
Std.
Deviation
2.072
2.235
3.139
1.483
0.983
Variance
4.077
4.746
9.333
2.090
0.918
TABLE 8. OBSERVED MANGANESE CONCENTRATIONS
WEEKLY COMPOSITE SAMPLES
NOV. 1, 1979 to MARCH 21, 1980
Sample
Location
Influent
Sewer Simulator
Effluent
Grit Chamber
Effluent
Primary Effluent
Activated Sludge
Effluent
Number of
Analyses
20
20
19
20
20
Arith.
Mean
0.62
0.63
0.69
0.57
0.44
Std.
Deviation
0.167
0.162
0.194
0.214
0.121
Variance
0.027
0.025
0.036
0.044
0.014
462
-------
TABLE 9. OBSERVED NICKEL CONCENTRATIONS
WEEKLY COMPOSITE SAMPLES
NOV. 1, 1979 to MARCH 21, 1980
Sample
Location
Influent
Sewer Simulator
Effluent
Grit Chamber '
Effluent
Primary Effluent
Activated Sludge
Effluent
Number of
Analyses
20
19
20
20
20
Arith.
Mean
0.30
<0.29
<0.28
<0.25
<0.21
Std.
Deviation
0.130
0.137
0.093
0.073
0.022
Variance
0.026
0.028
0.008
0.005
0.0005
TABLE 10. OBSERVED LEAD CONCENTRATIONS
WEEKLY COMPOSITE SAMPLES
NOV. 1, 1979 to MARCH 21, 1980
Sample
Location
Influent
Sewer Simulator
Effluent
Grit Chamber
Effluent
Primary Effluent
Activated Sludge
Effluent
Number of
Analyses
19
19
18
19
20
Arith.
Mean
0.953
1.005
1.044
0.684
0.052
Std.
Deviation
0.448
0.414
0.498
0.572
0.033
Variance
0.190
0.163
0.235
0.310
0.001
463
-------
TABLE 11. OBSERVED ZINC CONCENTRATIONS
WEEKLY COMPOSITE SAMPLES
NOV. 1, 1979 to MARCH 21, 1980
Sample
Location
Influent
Sewer Simulator
Effluent
Grit Chamber
Effluent
Primary Effluent
Activated Sludge
Effluent
Number of
Analyses
20
20
19
20
20
Arith.
Mean
1.25
1.25
2.10
1.23
0.41
Std.
Deviation
0.608
0.645
1.750
1.387
0.229
Variance
0.352
0.396
2.900
1.828
0.050
464
-------
100
m-m— INF
—A_A — PE
•—• ASE
NOV DEC
1979
JAN FEB
1980
Figure 2. Observed Cadmium Concentrations
465
-------
2.4
CC
O
2.0
1.5
1.0
1 1 1 1 1
— A—A —
1 1 1
INF
PE
ASF
1 1 1 1 1 1
NOV ' DEC
1979
JAN 'FEB
1980
Figure 3. Observed Chromium Concentrations
466
-------
1 .4
O
1.2 -
1 .0 —
0.2 -
NOV DEC
1979
JAN FEB
1980
Figure 4. Observed Copper Concentrations
467
-------
Iron
Both the primary clarifier and the activated sludge process were instru-
mental in reducing Fe concentrations, as the data in Table 7 and Figure 5
indicate. The standard deviation and variance were relatively high for ob-
served Fe concentrations at all sample locations, and the activated sludge
process did not do a consistent job of limiting Fe concentrations.
Manganese
The data for manganese are summarized in Table 8. As expected, none of
the unit processes/unit operations were particularly effective in limiting
observed Mn concentrations.
Nickel
A significant number of analyses for nickel were below the detection
limit, as the less than values in Table 9 indicate. Additionally, no process
significantly changed the observed mean concentrations of Ni.
Lead
Table 10 summarizes the data for lead. The activated sludge process,
and to a lesser degree the primary clarifier, were effective in removing lead
from the wastewater flows. The data shown in Figure 6 illustrate how effec-
tive the biological process can be in controlling transient Pb concentrations
Zinc
The data for Zn are shown in Table 11 and Figure 7. The activated
sludge process was reasonably effective in damping the observed Zn concen-
trations. The reason for the increase in Zn in the grit chamber effluent is
unknown at this time.
Metals Removal Summary
The observed metals removals for the primary clarifier and activated
sludge process are presented in Table 12. The removal values are computed
on the basis of the previously discussed mean concentrations, and calcula-
tions based on median or model concentrations will clearly yield different
results. Additionally, the presently available data base consists of only
20 values per metal per sample location. These data are too limited to per-
mit the formulation of any definitive conclusions; nevertheless, they do pro-
vide valuable perspective.
The primary clarifier appears to provide significant removals for Fe,
Pb, and Zn. However, the Zn concentrations in the influent to the primary
clarifier (grit chamber effluent) seem questionable. If either the influent
or sewer simulator effluent concentrations were used in the calculation, the
Zn removal observed in the primary clarifier would be zero.
468
-------
10 -
_J
^».
(3
LU
U.
NOV DEC
1979
JAN FEB
1980
Figure 5. Observed Iron Concentrations
469
-------
O
m
a.
2.0
fNF
PE
ASE
N O V DEC
1979
JAN FEB
1980
Figure 6. Observed Lead Concentrations
470
-------
3.0
2.5 -
NOV DEC
1979
JAN FEB
1980
Figure 7. Observed Zinc Concentrations
471
-------
TABLE 12. OBSERVED METALS REMOVALS
METAL
Ag
As
Cd
Cr
Cu
Fe
Hg
Mn
Ni
Pb
Zn
Observed Metal Removal (Percent)
Primary Clarifier
37.5 *
n.d.
26.1
17.5
2.3
51.3
n.d.
17. A
10.7 *
34.5
41.5
Activated Sludge
0 *
n.d.
87.1
72.3
88.4
61.2
n.d.
22.8
16.0 *
92.4
66.7
n.d. - majority of analyses were below detection limit
* - reported, but of limited statistical reliability due
to high number of analyses below the detection limit
472
-------
Cd, Cr, Cu, Fe, Pb, and Zn all appear to be removed relatively effec-
tively bv the activated sludge process. Table 13 presents metals removals
observed in activated sludge processes in this study conducted in Cincinnati,
and in two previous projects conducted in Dallas, Texas. The Dallas data
come from a two and one-half year study of metals removals by AWT processes-'-,
and a six-month drinking water reuse study. The activated sludge process at
Dallas was a completely-mixed system with a four-hour residence time, and an
average flow of about 200 gpm. Although the differences in the two activated
sludge systems (Cincinnati and Dallas) are considerable, the data indicate
the same general pattern with respect to metals removals. Ag, As, Mn, and Ni
are not significantly affected, while Cd, Cr, Cu, Fe, Pb, and Zn are all sub-
stantially reduced.
The concentration of the metal in the influent to the process will
greatly affect the observed reductions, and Table 14 presents the mean in-
fluent concentrations for both the Cincinnati and Dallas based research.
Some rather significant differences exist, especially notable are Cr, Cu, Fe,
Mn, Pb, and Zn.
ORGANIC PRIORITY POLLUTANTS
The initial set of organic compounds selected for study are given in
Table 15. The components are present in a toluene solvent, and are pumped
into the influent of the experimental treatment sequence (sequence B). Most
compounds are spiked at an initial concentration of 50 micrograms/liter,
with the exceptions of bis(2-ethylhexyl) phthalate which is spiked at 100
micrograms/liter and Arochlor 1254 and Toxaphene which are at 150 micrograms
per liter.
The first set of 24-hour composite samples for GC-MS analysis was col-
lected on January 6, 1980. Partial results are shown in Table 15. All of
the samples were extracted, concentrated, and cleaned-up in the laboratory
operated by the Waste Analysis and Identification Section (WA&IS), Technology
Development and Support Branch, Wastewater Research Division, Municipal
Environmental Research Laboratory, Cincinnati, Ohio. The GC-MS analyses were
performed by the WA&IS laboratory and by the Toxicants Analysis Laboratory,
National Space Testing Laboratory, U.S. EPA, Bay-St. Louis, Mississippi.
To date sufficient samples have not been processed to permit calculation
of recovery factors for each compound in the various wastewater and sludge
matrices; therefore, the reported concentrations are uncorrected with res-
pect to recovery factors.
The data available for the primary effluents indicate that recoveries
range from 70 to 90 percent for the PAH's, from 70 to 100 percent for the
phthalates, from 95 to 100 percent for the phenols, and from 90 to 100 per-
cent for the pesticides.
The data in Table 15 are only preliminary, but they indicate that the
conventional treatment processes should be reasonably effective in removing
the PAH's and to a lesser extent the phthalates. There are too few data,
473
-------
TABLE 13. METALS REMOVAL BY ACTIVATED
SLUDGE PROCESSES
Metal
Ag
As
Cd
Cr
Cu
Fe
Mn
Ni
Pb
Zn
Cincinnati
Study
0*
n.d.
87
72
88
61
23
16*
92
67
Dallas2
Metals Study
51*
9
49
65
68
43
26
25
54
62
Dallas1
Reuse Study
n.d.
19
58
65
74
9
42
n.d.
53
44
n.d.
*
1
2
- not detected or not run
- reported, but of limited statistical reliability due
to high number of analyses below the detection limit
- acidified weekly composite samples
- acidified daily composite samples
474
-------
TABLE 14. OBSERVED MEAN METALS CONCENTRATIONS
IN ACTIVATED SLUDGE PROCESS INFLUENTS
Metal
*
Ag
-t.
As"
Cd'"
Cr
Cu
Fe
Mn
Ni
Pb
Zn
Cincinnati
Dallas
(mg/1)
<1.5 ; 0.78
< 20 14.8
21
0.47
0.86
2.42
0.57
<0.25
0.68
1.23
14
0.21
0.22
1.07
0.08
0.11
0.11
0.37
- micrograms per liter
475
-------
TABLE 15. PARTIAL RESULTS* FOR SAMPLES OF JAN. 6, 1980
Compound
Acenaphthene
Anthracene
Benzo (a) anthracene
Chrysene
Fluoranthene
Fluorene
Ideno ( 1 , 2 , 3 , cd) py r ene
Naphthalene
Phenanthrene
Pyrene
Bis (2-ethylhexyl) phthalate
Butyl benzyl phthalate
Di-n-butyl phthalate
Diethyl phthalate
Dimethyl phthalate
Di-n-octyl-phthalate
2,4 - dimethyl phenol
Pentachlorophenol
Phenol
Arochlor 1254
Endosulfan I and II
Heptachlor
Lindane
Toxaphene
Control Sequence Experimental Sequence
Inf.
(ug/D
1.4
10.2
-
-
2.6
20.0
-
34.5
10.0
1.4
23.6
2.9
6.2
4.4
-
1.3
32.2
-
122.
-
-
78.7
14.2
-
Pri.
Eff.
(us/D
5.0
4.0
-
-
-
4.5
-
18.7
4.0
-
50.8
4.3
-
4.5
-
-
-
17.5
-
-
-
-
-
—
A.S.
Eff.
(yg/D
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
n.a.
n.a.
n.a.
n.a.
n.a.
n.a.
n.a.
n.a.
Spiked
Inf.
(ug/D
47.0
37.5
46.6
46.6
44.3
56.2
-
75.2
37.5
44.5
76.8
38.9
43.2
57.0
50.2
45.1
58.7
190.
316.
-
-
63.2
56.5
—
Pri.
Eff.
(PR/1)
36.1
29.4
20.8
20.8
29.4
40.6
-
40.7
29.4
27.1
198.7
101.6
83.5
108.4
67.7
74.5
63.2
158.
176.
-
-
38.4
61.0
—
A.S.
Eff.
(us/D
-
-
0.7
0.7
-
-
-
-
-
2.9
7.4
0.4
1.1
0.4
-
1.0
n.a.
n. a.
n.a.
n.a.
n.a.
n.a.
n.a.
n.a.
* Values reported have not been corrected for recovery factors
n.a. - No analysis
- Not detected
476
-------
with too much variability, to make any statement relevant to either the
phenols or the pesticides.
An additional seven or eight samples will be collected for GC-MS analy-
sis with the present set of compounds in the spike solution. This should
provide an adequate data base from which relatively meaningful statistical
observations can be made. At the conclusion of this study a different set
of organic compounds will be selected for future studies, Additionally, two
more parallel, 1.5 gpm treatment sequences will be brought on-line in early
summer. The added sequences will permit either the study of three different
sets of compounds with a control or studying the same set of compounds at
three different concentrations.
The volatile compounds will be investigated using apparatus with a de-
sign flow of 35 gpm, in which the aeration basins have a SWD of 12 feet.
This equipment will more closely approximate stripping in an actual treat-
ment plant than would the 1.5 gpm systems which have an aeration basin SWD
of 4.5 feet. The large-scale apparatus to be used in the volatile priority
pollutant studies is scheduled for start-up in early July 1980.
REFERENCES
Petrasek, A. C., Jr., and Rice, I. M. "Water Reuse Research." Proceedings of
the AIChE-EPA Complete Reuse Symposium, Cincinnati, Ohio, June 1976.
Petrasek, A. C., Jr. Wastewater Characterization and Process Reliability for
Potable Wastewater Reclamation, Report No. EPA-600/2-77-210, Municipal
Environmental Research Laboratory, U.S. EPA, Cincinnati, Ohio, November
1977.
477
-------
PB83-1U2430
EFFECT OF COMBINED TREATMENT ON
PRIORITY POLLUTANTS IN POTW'S
F. B. DeWalle
D. A. Kalman
Department of Environmental Health
University of Washington
Seattle, WA 98195
E. S. K. Chian
Department of Civil Engineering
Georgia Institute of Technolcgv
Atlanta, GA 30332
INTRODUCTION
Recent studies have shown the widespread presence of trace contaminants
in the environment. Through improved analytical methodologies, trice con-
pounds can now be detected routinely at the parts per billion, anc sor.etiT.es
at the parts per trillion level.
The present study evaluated the efficiency of different treatment pro-
cesses to remove trace contaminants from wastewater. Since considerable
quantities of industrial chemicals are discharged into municipal severs, the
study evaluated removal efficiencies in plants receiving variable amounts of
industrial contributions. The treatment processes remove these contaminants
from the liquid wastestream and accumulate them on the solids leaving the
process such as primary sludge, waste activated sludge, and anaerobic
digested sludge. The other major removal step is volatization.
ANALYTICAL METHODOLOGY
The analytical scheme used in the current study detects organics with
a wide range of physical-chemical properties ranging from very volatile
organics, such as chloromethane, to the more hydrophobic compounds, such
as polychlorinated biphenyls (PCB's).
Development of the list of priority pollutants, which also includes 13
metals and asbestos and cyanide, for a total of 129 individual compounds,
resulted from the suit, NRDC vs. Train (U.S. EPA), forcing the EPA to define
toxic and hazardous waste materials and to establish discharge requirements
for each of these materials.
478
-------
Detailed pretreatment regulations, yet to be published, will include
priority pollutant discharge limits for individual industrial groups,
including POTW's. The discharge limits will be incorporated into the new
generation of NPDES permits that will be developed for virtually all permit-
ted dischargers over the next five-year period.
The analytical scheme uses an acid methylene chloride extraction, bio-
beads S-X2 separation to remove lipids, florisil clean-up to remove hydro-
carbons and a cesium silicate fractionation to remove phenols from neutral
compounds (Figure 1). The compounds are subsequently screened by GC and
identified by GC/MS analysis using a 30m x 0.25mm SE-54 capillary column
directly coupled to the mass spectrometer.
PRIORITY POLLUTANTS IN SEWAGE AND SLUDGE
The present study sampled 25 POTW's receiving different percentages
of their waste stream from industrial dischargers. Among the volatile
organics, trichloroethene was found at the highest concentration.while the
highest median values were noted for dichloromethane, tetrachloroethene,
methylbenzene, and 1,4-dichlorobenzene. A typical frequency distribution
curve for the benzenes in the incoming sewage at the POTW (Figure 2) shows
a variability of three orders of magnitude. As these aromatic compounds
adsorb onto the suspended solids in sewage, they are removed during primary
sedimentation. The accumulation ratio, i.e. the concentration in the
sludge divided by the sewage concentration, of the benzenes generally ranges
from 1 to 1,000 resulting in an even greater concentration variability
among plants (Figure 3). Among the different priority pollutant fractions,
the largest accumulation was noted for phthalates and polynuclear aromatic
hydrocarbons (Figure 4). The nitroamines may well be formed in the digester
in the presence of nitrified sludge and amino acids. Very little accumu-
lation of the volatile chlorinated C. and C_ compounds is noted.
The total concentration of organic priority pollutants was also ob-
served to be dependent on the percent contribution of industrial wastes in
each treatment plant (Figure 5). This relationship also suggests that
potential for control exists.
It was observed that the chlorinated C,-C? compounds, the Cl/aklyl
benzenes, and phenols all exhibit fairly strong dependence on percent
industrial waste flow. Total phthalate concentrations, on the other hand,
appear to be essentially independent of the fraction of industrial waste
flow. These data suggest that industrial pretreatment may be effective
for reducing concentrations of the solvent substances in phenols, but may not
be effective for control of certain classes of compounds, such as the
phthalates.
REMOVAL EFFICIENCIES OF PRIORITY POLLUTANTS
When the discharge of priority pollutants is difficult to control at
the source, the POTW becomes the only alternative to prevent these compounds
from entering the environment. Variable removal efficiencies have been
observed at the POTW for different types of organics.
479
-------
The limited data show that the removal of the total priority pollutant
load was about 48 percent during primary treatment and 61 percent during
secondary treatment. This corresponds to a BOD removal of 36 percent and
TSS removal of 67 percent during primary treatment and a BOD removal of 95
percent and TSS removal of 97 percent during secondary treatment. The
lower than expected removal during secondary treatment is due to the inabil-
ity to substantially remove a few of the priority pollutants, such as
methylene chloride and dichlorobenzene, are formed during the chlorination
process.
The removal efficiency of the priority pollutants during the primary
sedimentation process is likely due to the adsorption of the organics onto
the solid particles and the subsequent removal of these particles by sedi-
mentation. As the extent of adsorption increases with increasing molecular
weight of the organic compounds, the organic removal efficiency of the pri-
mary treatment step was found to increase with higher molecular weights.
The removal efficiency of the secondary treatment process employing
activated sludge is due to bacterial degradation, adsorption onto the bio-
mass and volatilization durina the aeration stso. The highest removal
observed for the chlorinated C -C., is likely
-------
basins; adsorbable organics will accumulate in the primary and secondary
sludge and thus pose a solids disposal problem. Source control, if
practicable, should receive the highest priority in controlling the dis-
charge and proliferation of compounds in the environment.
481
-------
AQUEOUS PHASE ADJUST pH
TO 12 PEEXTP.ACT 12 HCUPS
I
METHYLENECHLTj-lOE EXTRACT
DRY OVER Na.SO,
K-D CONCENTRATE TO 1 ML
ADD INTERNAL STANDARD
GC-.GC/MS ANALYSIS; BASES
K-D CONCENTRATE;EXCHANGE
INTO METHYLENECHLORIDE
I
ADD INTERNAL STANDARD
I
GC;GC/MS;PESTICIDES +
LIGHT PAH
FLORISIL FRACTION
"F "
1000 ML AQUEOUS SAMPLE
pH SET TO 2
12 HOURS CONTINUOUS
L-L EXTRACTION WITH STIRRING
METHYLENECHLORIDE EXTRACT
DRY OVER Na2S04
K-D CONCENTRATE TO 1 ML
ADD 1 ML PENTANE
GPC ON BIOBEADS 40 S-X 2
ELUTE MITH 50% METHYLENE '
CHLOP.IDE/PENTANE
TAKE 3 FRACTIONS
75-110 ML: K-D TO 2 ML
EXCHANGE INTO PENTANE
AZEOTROPICALLY
110-230 ML: FLOW-THROUGH
COUPLED COLUMN CHROMATOGRAPHY
ON CESIUM SILICATE
0-75 ML DI
LIPIDS
"V
15 ML PENTA
HYDROCARBON
"FT"
200 ML 50%
M9
3CARD LOAD c<1 20
ELUTE WITH
.NE DISCARD
S
ETHER/PET. ETHER
50 ML 100S
20 GR FLORISIL + H~0 COLLECT ELUATE PLUS 30ML
ELUTE WITH PENTANE AND ETHER METHYLENE CHLORIDE; K-D
ADD INTERNALSTANDARD
I
GC,GC/MS HEAVY PAH
"SILIATE FRACTION-A3"
ELUTE CESIUM SILICATE WITH 60ML
METHANOL; K-D
PARTITION 3X BETWEEN IN ACID
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Figure 1.
482
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-------
PB83-1U2448
HEAVY METALS IN MUNICIPAL WASTEWATER TREATMENT PLANT INFLUENTS:
AN ANALYSIS OF THE DATA AVAILABLE FROM TREATMENT PLANTS
R.A. Minear, M.W. Cantrell, R.L. Church
Department of Civil Engineering
The University of Tennessee
Knoxville, Tennessee 37916
S. A. Hannah
USEPA - MERL-WRD
Cincinnati, OH 45268
R.O. Ball
Roy F. Weston, Inc.
Weston Way
West Chester, PA 19380
ABSTRACT
The preliminary results of a 2-year study involving the identification
and assembly of a data base existing within the Publicly Owned Treatment
Works (POTW) of the U.S. on influent heavy metals is presented. The general
character of the data base with respect to associated descriptors (among
which are % industrial contribution, % combined sewers, % infiltration/inflow,
sample frequency, sample type, analytical method) is provided. Wastewater
treatment plant laboratories were evaluated in the conduct of the study and
generally found to be satisfactory within the framework of the evaluation
method. Of the 80,000 individual pieces of data from 239 wastewater treat-
ment plants, a substantial data base was generated for cadmium, chromium,
copper, nickel, lead and zinc. Extensive data (but reduced in total volume)
were obtained for silver, arsenic and mercury. Limited data were obtained
for beryllium, cobalt, antimony and selenium. Aluminum, iron and manganese
data were received well. Median and mean (computed in varying manner) are
reported and compared. While no associations could be demonstrated between
the median or mean values for the composite data base and the individual
descriptors using Pearson and Spearman techniques, isolation of the low per-
cent industrial waste category from the parent data base did show a signifi-
cant differences for 6 of 7 metals. Lead was the metal not showing a
difference.
INTRODUCTION
A study has been conducted over the last two years in which municipal
wastewater treatment facilities have been surveyed to determine which plants
488
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possess data on heavy metals concentrations in their plant influent. The
study objectives were as follows:
1. Determine the extent and character of the national data base for
publicly owned treatment works (POTW) influent metals concentration.
2. Provide an indication of the quality of the data base via direct
laboratory evaluation.
3. Obtain and computerize a representative sampling of the defined
data base in conjunction with an array of descriptors for the data
source.
4. Summarize the quantitative character of the data base and examine
variations relative to the array of descriptors obtained.
This paper will report on items 1 to 3 above that define the character-
istics of the data base assembled and present some of the preliminary exami-
nations of the data base (item 4).
PROCEDURE
The initial phase of the research was to determine which cities did in
fact possess data on raw sewage metal concentrations at the treatment plant
inlet. While some information was obtained from Regional EPA and State
agency officials, most of the information obtained was by direct telephone
contact with individual cities. In addition to cities and contact names pro-
vided by EPA and State agencies, an arbitrary population limit of 25,000 was
set and all cities with this population or greater were listed. In total,
900 cities were selected for contact. Based on 1970 Rand McNally data, these
cities represented a total population of 84,197,837 or roughly 41% of the
United States population.
Affirmative responses to the question of whether or not heavy metals
were assayed in the plant influent were followed up with a simple mail form
that contained the information recorded from the telephone contact. The
cities were asked to verify the information recorded. From the telephone
survey, 444 cities gave indication of influent metals data. Of these, 287
operated their own POTW and 157 contributed to regional plants. The mail
follow-up of these responses generated a slightly different picture. Now
262 cities (representing 347 individual treatment plants) indicated influent
heavy metals data were obtained.
The second phase of the research was to obtain actual data from all
cities willing to provide data. Because of variations in the amount of data
available from each city and physical limitations in the anticipated com-
puter coding of the data, requests for data were based on the frequency of
analysis as follows:
489
-------
Frequency of Analysis Data Requested
^ 50/yr. 1 year
> 10 but < 50/yr. 2 years
^ 10/yr. 4 years or what
was available
The requests for data determined that 88 cities that had reported
influent data were available, measured metals only in the plant effluent.
Ultimately, data were received from 154 cities representing 239 individual
treatment plants. Sixteen additional cities promised data but did not send
even after repeated telephone follow-ups.
DATA BASE CHARACTERISTICS
Table 1,presents the distribution of plants supplying data by EPA re-
gion. Clearly, the data base is dominated by regions III, IV, V and IX.
Nine states did not supply data. These were Alaska, Idaho, Maine, Nebraska,
New Mexico, North Dakota, South Dakota, West Virginia and Wyoming. Of these,
only South Dakota reportedly had 1 city with data which were not sent.
States which had large numbers of plants with data were as follows:
California 32 plants
New York 18 plants
North Carolina 15 plants
Tennessee 14 plants
Indiana 13 plants
Illinois 11 plants
Virginia 11 plants
Pennsylvania 10 plants
Massachusetts 10 plants
Contrasted with an earlier study by Burns and Roe (1). this data base
represented 41 states compared with 20 by the earlier study which had its
data base heavily concentrated in Connecticut, Kentucky, New Jersey, Pennsyl-
vania and Wisconsin. On the other hand, the earlier study represented 269
individual treatment plants and thus likely had greater representation from
cities with a population of less than 25,000.
Descriptors
Information was sought in conjunction with the data supplied regarding
the nature of the sample taken, frequency of sampling (implicit in data sup-
plied), type of analytical procedures used, and whether or not analysis was
done in-house. Furthermore, plants were requested to supply information
regarding industrial contribution to the influent (both on a % flow and % of
BOD basis) and the sewer system characteristics. The latter consisted of
estimates of percent of combined sewers (nearest 10%), percent of flow at-
tributable to stormwater (nearest 10%) and the magnitude of infiltration and
inflow (3 categories only, <25%, 25 to 100%, >100%). Tables 2-9 summarized
490
-------
these descriptors in terms of the number of treatment plants in each for the
particular descriptor for each of the individual metals for which data have
been supplied.
The first observation from these data is that the dominant metals mea-
sured are cadmium, chromium (total), copper, nickel, lead and zinc, all with
over 200 plants measuring. Silver, arsenic, iron, mercury and manganese
represent an intermediate group with aluminum, cobalt and selenium showing
much lower numbers of plant measuring. The balance of the metals represented
in Tables 2-6 are measured by so few plants that one cannot say that a use-
ful data base exists.
The dominant treatment plant type making influent measurements is an
activated sludge plant (Table 2). For those 6 elements measured by large
numbers of treatment plants, weekly sampling generally is most common with
monthly sampling a close second followed, again closely, by daily sampling
(Table 3). For silver, arsenic, mercury and selenium, most of those plants
measuring did so monthly and, to a lesser extent, quarterly. By far, the
greatest number of plants made measurements on a 24-hr, composite sample,
although a significant number failed to report sample type (Table 4). Seven-
day and 30-day composite samples would correspond to weekly and monthly
sampling frequencies while 24-hr, composite samples could also apply to those
sampling frequencies. Of importance is that the majority of samples are com-
posites and flow proportioning was the most common practice.
By far, the dominant analysis method was atomic absorption spectrophoto-
metry as is illustrated in Table 5. Plant visits confirmed this observation.
When wet chemistry or Hach kit measurements were employed, they were gen-
erally used for relatively few metals, most commonly copper and chromium.
Most of the data represent analyses conducted by analysts at the treat-
ment plant or a central municipal laboratory rather than by commercial
laboratories (Table 6).
The distribution of plants by industrial flow contribution (Table 7)
presents a reasonable spread with appreciable representation in the 0 to 4%
category. For those metals measured by a large number of treatment plants,
the 10 to 19% and 20 to 39% categories dominate. Relatively few treatment
plants handle greater than 60% industrial waste as might be expected. These
data do not differentiate with respect to industrial type, although in many
cases information was supplied regarding dominant industrial contributions.
This issue will be of significance in examining metals concentration in re-
lation to industrial flow. Tables 8 and 9 show distributions of plants with
respect to combined sewers and infiltration and inflow, respectively. Each
of these factors relates to effects that climatological variations may have
on influent metals concentrations and these effects may work opposite to
other influences with subsequent obliteration of apparent relationships be-
tween metal concentrations and system descriptors. For most metals, roughly
half of the plants reported zero percent combined sewers with the balance
distributed among the other three (arbitrary) ranges but predominantly in
the 60 to 100% category.
491
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Laboratory Quality Index
Of the 154 cities represented by the 239 treatment plants, 140 (91%)
were visited and their laboratories evaluated using a modification of a
procedure contained in an EPA report, "Evaluation of Environmental Monitoring
Laboratories" (2). Calculation of the lab quality index (LQI) has been des-
cribed previously (3) and the complete rating form used is presented else-
where (4). Default items contained in the original documents' rating scheme
and which were carried over to the modified form, were counted for each
laboratory but not used directly to discount the validity of any laboratory's
data. Furthermore, the absolute LQI cannot be directly assigned meaning as
to the competence level of the laboratory, The original evaluation procedure
set a score of 60 as the minimum passing score. This significance was main"
tained in the modified procedure used and consequently, scores below 60
clearly indicate reason to question the reliability. On the contrary, an
LQI of 90 does not necessarily indicate a proportionally greater confidence
in data reliability versus an LQI of 80.
The distribution of LQI values by EPA region is presented in Table 10.
All but 3 laboratories achieved a passing score based on the criterion estab^
lished. For the most part, the LQI values would imply that the data base is
of acceptable analytical reliability.
Table 11 contains a summary of information that has been received from
239 treatment plants and entered into the computer. Data supplied were
usually in the form of copies of laboratory records and contain entries for
zero concentrations or less than a particular value, For some metals, the
combination of less than or zero values was high. Notably, arsenic, cadmium
and selenium had 42, 41 and 44 percent of the values reported in this fashion.
Zinc and copper, on the other hand, were reported mostly as discrete values
with only 2 and 8 percent of the values reported as zero or less than,
respectively.
The range of values for each metal presented in Table 11 may reflect
individual analytical anomalies at a given municipality but were the values
supplied as verified by follow-up communication. Working with the data set
requires some selective editing to evaluate if anomalous values are the re^
suit of infrequent or one-shot grab sampling, a single outlier in the data
set, interference prone analysis and/or a low LQI.
DATA BASE EXAMINATION
Mean and Median Concentrations
For the case where no data editing is involved, the question arises as
to how one handles inordinately high values or the zero and less than values,
Furthermore, should equal weight be given to plants with fewer data points
(even though the request procedure attempted to normalize this variation)?
In looking at mean values and attempting to compute mass flow, concern must
492
-------
be directed at the "zero" or less than value. Is it really zero or just
below the detection limit? The data of Tables 12 and 13 examine the dif-
ference between median and mean values, the latter computed in several
different ways. Table 12 refers to "weighted values" defined as follows:
Z(plant median x # of observations for plant)
Weighted Median = —-^——, r 7—7 : ; £ -
6 I(number of observations per plant)
T . , , „, S(plant mean x // of observations for plant)
Weighted Mean = „ , j— : ^ -
0 E(number of observations per plant)
_ Eindividual values
total // of values
The former is actually a weighted mean of the median values while the latter
is the overall mean of the composite data base. In both Tables 12 and 13,
the» mean values have been computed in four different ways: (1) Mean, LT=0
is computed by setting all less than values equal to zero and counting these
and zero values in the denominator; (2) Mean, LT=value is computed by in-
cluding zero values and setting all less than values equal to that value;
(3) Mean, LT,0=Detection Limit is computed by setting all zero and less than
values equal to the detection limit, either as reported or determined by
the computer through selection of the lowest reported discrete value;
(4) Mean, Discrete Values is computed by excluding all zero and less than
values.
For the data of Table 12, the median values are consistently lower than
all of the means (with the exception of arsenic) although in some cases lit-
tle change is noted. Because of zero values, for some plants the individual
medians are reported as zero and these values depress the mean of the medians
relative to the mean values. Obviously, this is the result of more than 50%
of the recorded values being zero. Setting of less than values equal to
zero resulted in mean values less than the median values only for arsenic,
beryllium, cobalt, antimony and selenium. For each of these elements, high
percentages of the total observations were reported as less than or zero
(42, 81, 27, 94 and 44%,respectively). For those metals for which a large
number of observations were available (Cd, Cr, Co, Cu, Hg, Ni, Pb and Zn)
the median values and the 3 mean values that considered zero and less than
values in one manner or another were relatively close in magnitude (20 to
30%) .
Comparison of Mean (LT=0) with Mean (LT=value) shows no significant
change for chromium, copper, nickel, lead and zinc. For cadmium an 11% in-
crease is seen and for mercury the increase is 40%. The large increase seen
for arsenic and the anomalous behavior for the median versus the mean values
is likely the result of unusual detection limits or less than values reported
by one or more plants especially if a large fraction of the total data set
comes from this source. The unweighted data smooth out this effect as will
be seen below.
The mean of the discrete values reported is higher than the other values
for silver, cadmium, chromium and nickel but by only 20 to 30%,not orders of
493
-------
magnitude. For other metals, the change is less (copper, mercury, lead and
zinc).
Another way of examining the data is to assume equal reliability of the
means and medians for each of the individual plant data sets. Table 13 pre-
sents the data in this manner, defined as follows:
TT . ,. , ,. Iplant medians
Unweighted median = —'-r —
number of plants
TT . ,. , Eplant means
Unweighted mean = c . —
number of plants
Unweighted median values are slightly higher for silver, cobalt, manga-
nese, nickel, lead and selenium, while the reverse occurred for arsenic,
beryllium, cadmium, chromium, copper, mercury, antimony and zinc. A similar
mix of plus and minus values was observed for the various unweighted means
when compared to the weighted counterparts,but the differences are generally
small except for mercury (unweighted values lower by roughly a factor of 10)
and selenium (unweighted values higher by roughly a factor of 10). Inter-
estingly, for the unweighted data, the change in values among the various
computed means and even the median were much less than observed for the
weighted values. Usually the median is less than the mean values and the
Mean (LT=0) is less than the other mean values. In some cases, this dif-
ference is very small while for arsenic, beryllium, cobalt and antimony,
larger changes are seen. Each of these elements has a large percentage of
zero and less than values and/or is measured by relatively few treatment
plants. Figure 1 contains a graphical presentation of the ranges, unweighted
median and mean (LT=value) values for those heavy metals included in the
priority pollutant list.
Distribution of Medians and Means
Cumulative distributions on the individual plant medians and means
typically resulted in compression of most values at the axis due to domi-
nance by 2 to 4 data points. Figures 2 and 3 illustrate this behavior for
arsenic and cadmium, respectively, for individual plant median concentra-
tions. Similar plots were obtained for each of the four means. Elimination
of the top 4 values and replotting the remainder provides a better view of
the data distribution as illustrated in Figures 4 and 5.
Examination of the highest 4 values for several elements for which sub-
stantial data were available indicated a pattern associated with those
values. Table 14 summarizes this pattern for 9 elements. More commonly
than not, the high values are associated with very few observations, Several
plants are repeatedly represented for the 9 elements, usually those with
limited observations; but in several instances, a substantial data base is
represented. In these cases decimal errors in coding may be suspect or
analytical interferences (example plant 298-1 analyzes for chromium by wet
chemical procedures rather than atomic absorption spectrophotometry) or the
plant has unusual contributions to its sewer. For the chromium case, plant
298-1 also reports a 40% industrial contribution by flow.
494
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These factors may lead to the apparent differences in median concentra-
tions in the ten EPA regions shown in Table 15. Copper and chromium values
are highly elevated in Region I relative to other parts of the country. The
two highest chromium and copper values are located in Region I which has only
15 plants represented in the total data base. Silver, arsenic and mercury
also show wide variation among the regions.
Relationship Between Concentration and Descriptors
The relationship between the various descriptors selected and median
(and the various mean) concentrations is illustrated for cadmium and zinc
median concentrations versus percent of industrial flow in Figures 6 and 7,
respectively. All such plots yielded similar scattergrams. Furthermore,
examination for both parametric (Pearson) and nonparametric (Spearman and
Kendall) associations did not yield large r values for any of the descriptors,
including percent industrial flow. While these results may be contrary to
expectations .and results from specific studies on a smaller population size,
they are not surprising when the entire data vase is used and emphasize the
need to examine with judgment. First, several of the descriptors which
would be expected to influence metals concentrations, work in opposition to
each other. Secondly, variations in sample types, frequency, analytical
method used and quality assurance program (if any) would lead to further
noise in the data set. Additional and more sophisticated examination of the
data is required and under study.
However, a significant number of plants reported low percent industrial
flow contribution for seven of the metals measured. Table 16 indicates the
distribution of plants in the 0 to 4% industrial category. Comparison of
the respective median values for these two groups is presented in Table 17
from which it can be seen that in all cases the low percent industrial con-
tribution values were lower. Application of the student T test to determine
if these values are significantly different proved positive in all cases
except for lead. Further comparisons of those plants reporting zero %
industrial flow with those reporting 2% (1.5 - 2.5%) industrial flow did not
show a significant difference for any of the metals except cadmium. The
average zero% cadmium median was 0.0022 mg/1 versus 0.0112 mg/1 for the 2%
industrial flow category (T = -14.50, ct<0.0005). Generally, similar values
were obtained for comparison of the composite and 0-4% industrial flow means
(discrete values).
In spite of the lack of correlation between percent industrial flow and
metals concentration, the data base does allow sorting out of the background
or base level contribution of several metals to POTWs from domestic sources,
Upon closer examination and sorting of the data, particularly in conjunction
with information on dominant industry types,, better association between
percent industry and metals concentrations might be expected,
495
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SUMMARY
In summary, a composite picture of the data base on influent heavy metal
concentrations to publicly owned treatment plants has been obtained. This
picture is different from that obtained by preliminary telephone contact and
initial correspondence with the municipalities. For the majority of munici-
palities responding, fairly detailed information has.been assembled charac-
terizing the data base in terms of plant type, frequency of sampling and
analysis, metals analyzed, analytical method used, industrial contribution,
extent of combined sewers and percent of infiltration and inflow. Over- 90%
of the cities were visited and their laboratories evaluated. The majority
of these were found to be satisfactory or better, lending confidence to the
reliability of the data base.
From the defined data base, a sampling of the individual plant data was
obtained from 88% of the cities representing 239 individual treatment plants
and nearly 80,000 data.points have been computerized. The quantitative
character of these data has been summarized, demonstrating wide variations
in the range of values reported. Statistical associations between individual
characteristics and the metals concentrations were not found for the com-
posite data base,yet indications were presented that proper isolation of
segments of the data with similar characteristics of sampling and analysis
may disclose associations obscured by the total data base. Another example
was shown for the low (0-4%) industrial segment of the data base versus the
composite data. For several metals, the former category was significantly
lower. Statistical analysis of the data base is continuing.
ACKNOWLEDGEMENT
The work presented in this paper has been supported under EPA Research
Grant //R805606-01, MERL, Cincinnati, The able assistance of Douglas Allen
and Lisa Sullivan, respectively graduate and undergraduate student in the
Department of Civil Engineering, The University of Tennessee, is gratefully
acknowledged.
REFERENCES
1. U.S. E.P.A., "Federal Guidelines - State and Local Pretreatment Pro-
grams," E.P.A. Reports - Nos. EPA-430/9-76-017a, b, and c, January 1977.
2. U.S. E.P.A., "Evaluation of Environmental Monitoring Laboratories,"
E.P.A. Report No. EPA-600/4-78-017, March 1978.
3. R. A. Minear, R. 0. Ball, R. L. Church and D. Hines, "Data Base Location
and Evaluation for Heavy Metals Discharge into Municipal Wastewater
Systems," Proceedings of the 8th National Conference on Municipal Sludge
Management, Information Transfer, Inc., Silver Spring, MD, pp. 48-54, 1979.
4. U.S. E.P.A., Final Report on Project #R805606-1, in press.
496
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TABLE 1. NUMBER OF TREATMENT PLANTS SUPPLYING
DATA BY EPA REGION
EPA Region
I
II
III
IV
V
VI
VII
VIII
IX
X
Number of Plants
15
24
32
40
48
17
15
8
37
3
239
497
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TABLE 2. DISTRIBUTION OF TREATMENT PLANT TYPES FOR
INDIVIDUAL METAL MEASURES
Number of Plants
Treatment Plant Tvpes
Primary
Metal Treatment
Ag
Al
As
B
Ba
Be
Ca
Cd
Co
Cr
Cr(III)
Cr(VI)
Cu
Fe
Hg
K
Mg
Mn
Mo
Ni
Pb
Sb
Se
Si
Sr
Ti
Tl
V
Zn
9
4
10
2
-0
2
0
22
2
22
0
1
25
10
17
0
0
5
0
21
21
0
1
0
0
0
0
2
24
Trickling
Filter
11
1
8
1
4
0
1
21
3
23
0
1
25
14
11
0
1
10
0
23
18
0
5
0
0
0
0
0
24
Activated
Sludge
28
25
22
5
7
2
2
104
23
117
3
5
123
80
50
1
2
38
3
104
100
7
11
13
1
1
2
2
119
Physical/
Chemical Other
3
3
4
0
0
1
0
5
2
6
0
1
6
5
4
0
0
3
2
6
5
2
1
0
0
0
0
0
6
4
0
2
0
2
0
0
7
3
7
1
1
7
5
3
0
0
3
0
7
6
0
2
0
0
0
0
0
7
Unknown
21
6
22
2
9
4
0
39
5
43
0
5
41
28
29
0
1
20
4
34
41
2
19
7
0
1
1
2
40
498
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TABLE 3. DISTRIBUTION OF SAMPLING FREQUENCY
FOR INDIVIDUAL METALS MEASURED
Number of Plants
Frequency of Sampling and Analysis
Metal
Ag
Al
As
B
Ba
Be
Ca
Cd
Co
Cr
Cr(III)
Cr(VI)
Cu
Fe
Hg
K
Mg
Mn
Mo
Ni
Pb
Sb
Se
Si
Sr
Ti
Tl
V
Zn
Daily
6
6
5
1
2
2
1
39
6
39
0
4
46
26
15
1
3
10
0
36
31
2
3
0
1
0
0
2
43
Weekly
10
3
3
0
2
1
0
51
10
60
0
1
62
42
22
0
0
12
0
54
49
2
3
11
0
0
0
0
60
Bi-
Weekly
2
0
3
1
1
0
1
7
4
9
1
2
10
2
4
0
0
2
0
5
6
0
2
0
0
0
0
0
7
Monthly
36
11
32
1
12
2
0
47
10
52
0
4
46
37
32
0
0
31
3
50
47
3
18
4
0
0
1
3
49
Quarterly
11
12
10
2
2
3
0
25
1
25
0
0
27
14
16
0
0
11
3
26
25
1
8
2
0
2
2
1
26
Semi-
Annual
6
1
6
1
1
0
1
8
2
9
3
3
11
5
8
0
0
4
0
9
11
1
2
0
0
0
0
0
11
Annual
1
4
4
3
1
1
0
6
3
6
0
0
7
8
4
0
0
5
2
5
5
1
1
2
0
0
0
0
6
Infr
4
2
5
1
1
0
0
15
2
18
0
0
18
8
13
0
1
4
1
10
17
1
2
1
0
0
0
0
18
499
-------
TABLE 4. DISTRIBUTION OF SAMPLE TYPES FOR
INDIVIDUAL METALS MEASURED.
Number of Plants
Sample Type
Metal
Ag
Al
As
B
Ba
Be
Ca
Cd
Co
Cr
Cr(III)
Cr(VI)
Cu
Fe
Hg
K
Mg
Mn
Mo
Ni
Pb
Sb
Se
Si
Sr
Ti
Tl
V
Zn
24 hr.
Composite
47
28
45
5
14
7
2
123
22
135
3
7
145
94
70
1
2
50
7
122
117
7
26
3
1
1
2
6
139
Composite
Unspecified
2
0
2
0
0
0
1
7
0
8
0
0
7
7
2
0
1
2
0
8
8
0
0
0
0
0
0
0
8
7 day
Composite
0
1
0
0
0
1
0
3
2
3
0
0
3
2
1
0
0
3
0
3
3
0
0
0
0
0
0
0
3
30 day
- Composite
2
0
2
0
0
0
0
13
0
13
0
0
14
11
13
0
0
2
0
14
14
0
2
11
0
0
0
0
14
Grab
1
4
4
2
1
0
0
10
5
10
0
0
10
4
5
0
1
3
1
6
7
1
2
1
0
0
0
0
8
Unknown
24"
6
15
3
7
1
0
42
9
49
1
7
48
24
23
0
0
19
1
42
42
3
9
5
0
1
0
0
48
500
-------
TABLE 5. DISTRIBUTION OF ANALYSIS METHOD BY INDIVIDUAL METALS
Number of Cities
Method of Measurement
Metal
Ag
Al
As
B
Ba
Be
Ca
Cd
Co
Cr
Cr(III)
Cr(VI)
Cu
Fe
Hg
K
Mg
Mn
Mo
Ni
Pb
Sb
Se
Si
Sr
Ti
Tl
V
Zn
Atomic
Absorption
65
35
55
6
18
9
2
182
20
188
1
8
198
128
101
1
3
72
8
178
167
10
34
15
1
2
3
6
191
Wet
Chemistry
1
0
7
1
3
0
1
0
9
6
1
3
2
4
0
0
0
2
0
1
3
0
4
4
0
0
0
0
3
Hach Kit
1
0
0
0
0
0
0
0
4
5
2
2
7
4
0
0
0
0
0
1
3
0
0
0
0
0
0
0
5
Other
2
3
0
1
0
0
0
3
2
4
0
0
4
3
2
0
0
1
0
3
4
0
0
0
0
0
0
0
3
Unknown
8
1
6
2
1
0
0
13
3
15
0
1
16
3
11
0
1
4
1
12
14
1
1
1
0
0
0
0
18
501
-------
TABLE 6. WHERE ANALYSES WERE CONDUCTED BY INDIVIDUAL METAL
Metal
Ag
Al
As
B
Ba
Be
Ca
Cd
Co
Cr
Cr(III)
Cr(VI)
Cu
Fe
Hg
K
Mg
Mn
Mo
Ni
Pb
Sb
Se
Si
Sr
Ti
Tl
V
Zn
Number
Outside Lab Analysis
15
6
11
5
5
4
1
20
8
22
2
2
23
13
14
0
2
10
4
21
20
2
8
2
0
1
1
0
22
of Plants
Internal Analysis
61
33
57
5
17
5
2
178
30
196
2
12
204
129
100
1
2
69
5
174
171
9
31
18
1
1
2
6
198
502
-------
TABLE 7. DISTRIBUTION OF PERCENT OF PLANT FLOW ATTRIBUTABLE TO
INDUSTRIAL CONTRIBUTION FOR INDIVIDUAL METALS MEASURED
Number of Plants
Percent of Industrial Flow
Metal
Ag
Al
As
B
Ba
Be
Ca
Cd
Co
Cr
Cr(III)
Cr(VI)
Cu
Fe
Hg
K
Mg
Mn
Mo
Ni
Pb
Sb
Se
Si
Sr
Ti
Tl
V
Zn
0-4
8
9
6
1
1
1
0
29
4
33
0
0
34
21
18
0
0
12
0
24
28
1
4
2
0
0
0
0
33
5-9
10
1
11
2
0
0
0
25
6
23
2
3
27
16
16
0
0
8
1
21
23
0
4
3
0
0
0
1
25
10-19
35
11
29
1
12
3
2
64
7
69
2
6
73
43
50
0
2
28
4
69
71
3
19
11
0
0
0
2
74
20-39
11
10
10
4
4
2
1
44
10
52
0
3
51
41
15
1
1
21
3
42
37
5
6
3
1
2
2
1
43
40-59
7
6
8
2
2
2
0
25
8
28
0
2
28
16
11
0
1
7
0
26
22
0
3
0
0
0
0
1
26
60-79
2
0
2
0
2
0
0
6
1
5
0
0
6
2
2
0
0
1
0
6
5
0
1
0
0
0
0
0
7
80-100
2
2
2
0
1
1
0
3
1
6
0
0
6
2
2
0
0
1
1
4
3
2
2
1
0
0
1
1
5
Unknown
1
0
0
0
0
0
0
2
1
2
0
0
2
1
0
0
0
1
0
3
2
0
0
0
0
0
0
0
2
503
-------
TABLE 8. DISTRIBUTION OF PERCENT COMBINED SEWERS
FOR INDIVIDUAL METALS MEASURED.
Number of Plants
Percent of Combined Sewers
Metal
Ag
Al
As
B
Ba
Be
Ca
Cd
Co
Cr
Cr(III)
Cr(VI)
Cu
Fe
Hg
K
Mg
Mn
Mo
Ni
Pb
Sb
Se
Si
Sr
Ti
Tl
V
Zn
0
46
28
39
6
13
2
1
104
21
117
2
10
122
73
52
0
2
48
5
98
92
9
21
8
0
1
2
1
117
1-30
13
5
13
3
4
5
1
20
8
22
2
2
25
12
17
1
1
7
4
19
23
2
6
1
1
1
1
0
25
31-60
5
5
4
1
4
0
0
28
6
32
0
1
32
21
16
0
0
10
0
29
30
0
2
0
0
0
0
2
30
61-100
4
1
2
0
1
1
1
33
3
34
0
1
35
27
19
0
1
4
0
36
34
0
1
11
0
0
0
2
35
Unknown
8
0
10
0
0
1
0
13
0
13
0
0
13
9
10
0
0
10
0
13
12
0
9
0
0
0
0
1
13
504
-------
TABLE 9. DISTRIBUTION OF PERCENT INFILTRATION AND
INFLOW FOR INDIVIDUAL METALS MEASURED.
Number of Plants
Percent Infiltration/Inflow
Metal
Ag
Al
As
B
Ba
Be
Ca
Cd
Co
Cr
Cr(III)
Cr(VI)
Cu
Fe
Hg
K
Mg
Mn
Mo
Ni
Pb
Sb
Se
Si
Sr
Ti
Tl
V
Zn
<25
20
10
16
3
7
2
1
58
9
68
1
3
69
43
33
0
1
18
1
57
55
2
4
12
0
1
1
0
65
25-100
34
24
33
4
10
5
2
82
16
86
2
7
94
59
48
1
2
37
6
86
82
7
22
6
1
1
1
5
92
>100
5
2
6
2
2
2
0
19
3
25
1
3
25
9
9
0
0
5
0
18
16
0
3
0
0
0
0
1
23
Unknown
17
3
13
1
3
0
0
39
10
39
0
1
39
31
24
0
1
19
2
34
38
2
10
2
0
0
1
0
40
505
-------
TABLE 10. LAB QUALITY INDEX DISTRIBUTION
Number of Cities with a Given LQI
LQI
48
53
59
60
61
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
83
84
85
86
87
88
89
91
93
94
96
1234
1
1
EPA Region
5 6 7,8 9 10
1 Minimum passing score
1
1
1
-
1
1
3
2
1
1
1
1
3
1 5
1
1 2
5
1 3
1
9
1 1
1
1
3
1
1 1
1 1
7
1 2
2
2
1
3
1
1
2 22
1 4
25 1
1 1
3 1
4
3 3
2 1
128
2 1
1
6
Total
" 1
1
1
3
1
2
1
4
2
2
3
4
8
4
3
2
1
4
6
4
4
6
6
4
5
8
2
4
4
7
3
11
3
1
15
16 20 38 16 11 3 22 1 140
506
-------
TABLE 11. SUMMARY OF HEAVY METALS DATA BASE FROM 238
WASTEWATER TREATMENT PLANT INFLUENTS.
Metal
Ag
Al
As
B
Ba
Be
Cd
Co
Cr
Cu
Fe
Hg
Mn
Mo
Ni
Pb
Sb
Se
Sn
Sr
Ti
V
Zn
Total
Number of
Observations
1,696
857
1,140
101
. 441
171
8,937
323
11,362
12,351
8,558
2,698
2,302
22
9,461
7,521
155
592
6
85
4
125
11,341
80,241
Observations
Number
-------
TABLE 12. COMPARISON OF MEDIAN AND MEAN VALUES (WEIGHTED)
FOR THE ENTIRE DATA BASE.
Ln
O
OO
Metal
Ag
Al
As
Be
Cd
Co
Cr
Cu
Fe
Hg
Mn
Ni
Pb
Sb
Se
Zn
#0bserv
1,696
854
1,140
171
8,937
323
11,362
12,351
8,558
2,698
2,302
9,461
7,521
155
592
11,341
//Plants
76
39
68
9
198
38
218
227
142
114
79
195
191
11
39
220
*
Median
.017
2.41
.085
.0091
.024
.053
.40
.42
3.18
.063
.16
.23
.12
.43
.041
.52
ft
Mean
LT=0
.024
3.39
.012
.0040
.027
.050
.45
.46
5.13
.11
.17
.31
.15
.24
.038
.63
ft
Mean
LT=Value
.026
3.39
.069
.0097
.030
.066
.45
.46
5.13
.14
.17
.32
.16
.37
.047
.63
. *
Mean
LT,0=Det.Lim.
.Q26
3.39
.069
.0098
.030
.066
.45
.46
5.13
.14
.17
.32
.16
.37
.047
.63
ft
Mean
Discrete Values
.032
3.44
.021
.0216
.046
.070
.52
.49
5.27
.14
.18
.39
.18
.37
.066
.64
Values reported as mg/1.
-------
TABLE 13. COMPARISON OF MEAN AND MEDIAN VALUES* (UNWEIGHTED)
FOR THE ENTIRE DATA BASE.
Ln
O
Metal
Ag
Al
As
Be
Cd
Co
Cr
Cu
Fe
Hg
Mn
Ni
Pb
Sb
Se
Zn
Median
.021
2.98
.048
.0069
.024
.056
.39
.35
3.44
.011
.35
.26
.14
.22
.31
.51
Mean
LT=0
.028
3.70
.035
.0025
.024
.035
.44
.38
4.79
.013
.37
.31
.16
.09
.28
.61
Mean
LT=Value
.030
3.72
.050
.0072
.029
.066
.45
.39
4.79
.019
.37
.32
.19
.22
.30
.61
Mean '
LT,0=Det.Lim.
.030
3.72
.050
.0076
.030
.067
.45
.39
4.80
.019
.37
.32
.19
.22
.30
.61
Mean
Discrete Values
.028
3.70
.035
.0025
.024
.035
.44
.39
4.79
.013
.37
.31
.16
.09
.28
.61
Values reported as mg/1.
-------
TABLE 14. LISTING HIGHEST 4 MEDIAN AND MEAN (DISCRETE
VALUES) FOR NINE ELEMENTS.
Median Values
Element
Arsenic
Cadmium
Chromium
Copper
Mercury-
Nickel
Lead
Selenium
Zinc
Plant #
456-1
432-1
635-1
4 Plants
456-1
577-1
359-1
514-1
298-1
715-5
584-1
643-1
58-1
179-2
2234-1
519-1
546-1
617-1
359-1
514-1
2234-1
359-1
58-1
456-1
295-3
295-9
491-1
359-1
295-3
617-1
15-1
15-2
58-1
2234-1
530-1
456-1
Median
mg/1
1.56
1.00
0.07
0.005
.85
.30
.20
.18
32 . 6#
4.9
3.1
2.8
26.0
11.5
1.7
1.03
0.60
0.50
0.028
0.010
11.3
9.5
2.4
1.5
8.5
2.7
1.1
0.72
10.0
1.0
.37
.19
10.3
3.14
3.12
3.10
# Observ
1
88 (75<)
8
1
32 (28<)
3
360
31
6
329
6
1
232
29
82
301
4 (4<)
3
2
29
3
1
1
1
4
3
3
1
6 (6<)
3
3
1
29
96
1
Discrete Value Mean
Plant #
456-1
877-4
877-3
641-1
456-1
514-1
359-1
295-1
298-1
715-1
715-5
715-3
58-1
179-2
2234-1
519-1
546-1
877-1
359-1
132-1
2234-1
359-1
58-1
215-1
295-3
295-9
321-1
491-1
295-3
15-2
15-1
2234-1
58-1
2234-1
530-1
456-1
Mean
mg/1
1.55
.48
.11
.065
.85
.19
.17
.13
33 . 3#
4.8
4.1
2.9
26.0
11.2
2.4
1.3
1.01
0.23
0.058
0.048
16.3
8.6
2.4
1.5
8.5
2.7
1.2
1.0
10.0
0.34
0.19
0.15
10.3
4.88
3.99
3.10
# Observ
1 *
7 (3<)
8 (5<)
17
1
360
3
3 (2<)
31
12
6
13
1
232
29
82
301
10 (1<)
3
79 (40=0)
29
3
1
234
1
4
139 (134=0)
3
1
3
3
34
1
29
96
1
(<) indicates number of total values reported as less than a particular value
wet chemical analysis. Others atomic absorption.
510
-------
TABLE 15. MEDIAN CONCENTRATION (UNWEIGHTED) BY EPA REGION
Region
I
II
III
IV
V
VI
VII
VIII
IX
X
Composite
National
Maximum
Ag
0.025
0.038
0.0035
0.059
0.0067
0.0051
0.022
0.0010
0.020
-
0.021
^Q
As
0.0080
0.0098
0.0017
0.21
0.010
0.0083
0.027
0.0010
0.0058
-
0.048
91 n
Cd
0.029
0.0092
0.0070
0.051
0.038
0.012
0.025
0.013
0.018
0.014
0.024
7 •}
Cr
3.40
0.093
0.12
0.092
0.37
0.064
0.34
0.081
0.18
0.10
0.39
s.i
Cu
2.45
0.28
0.16
0.081
0.47
0.10
0.14
0.19
0.25
0.21
0.35
in
0.0023'
0.0010,
0.0008
0.0031
0.031
0.0007
0.064
0.0044
0.0010
0.0013
0.011
Q1
Ni
0.52
0.54
0.11
0.42
0.18
0.065
0.14
0.22
0.15
0.080
0.26
s •}
Pb
0.29
0.075
0.23
0.092
0.15
0.056
0.15
0.089
0.12
0.13
0.14
•3 o
Zn
1.19
0.52
0.44
0.38
0.66
0.18
0.42
0.36
0.50
0.65
0.51
£. C.
Minimum
-------
TABLE 16. BREAKDOWN OF PLANTS REPORTING IN THE RANGE
OF 0-4% INDUSTRIAL FLOW CONTRIBUTION.
Number of Plants
Reporting
Indicated
Industrial Flow Contributions
Metal
Cd
Cr
Cu
Hg
Ni
Pb
Zn
0%
20
21
22
12
10
19
22
1%
4
4
4
2
2
3
4
2%
11
13
13
8
12
12
13
3%
0
0
0
0
0
0
0
4%
0
1
1
0
0
0
0
512
-------
L/1
M
LO
TABLE 17. COMPARISON BETWEEN COMPOSITE DATA BASE VALUES AND THOSE OBTAINED
FROM PLANTS WITH 0-4% INDUSTRIAL FLOW CONTRIBUTION.
Metal
Cd
Cr
Cu
Hg
Ni
Pb
Zn
Composite
Median
.023
.37
.34
.010
.26
.17
.50
0-4%
Median
.0064
.030
.097
.0005
.049
.11
.22
Composite Median
0-4% Median
3.6
12.3
3.5
20
5.3
1.5
2.3
A <
T
- 8.96
- 58.1
- 17.2
-104
- 27.3
- 0.741
- 8.28
a
«0.005
«0.005
«0.005
«0.005
«0.005
»0.10
«0.005
Significant
Difference
Yes
Yes
Yes
Yes
Yes
No
Yes
\
Student T test value.
-------
Ui
h->
-p-
No. Plcmti Metal
9 B.
83
71
11
212
124
41
205
234
238
232
203
Ag
At
Sb
Cd
Hg
Se
Pb
Zn
Cu
Cr
Nl
0.01
-t-
• Median
• Mean
f
0.10 1.0
Concentration , mg / I
10
100
Figure 1. Range of individual concentrations reported and unweight
median and mean (LT=value) concentrations for metals on
the priority pollutant list.
-------
O
•
O
{O
as'
CO
too
Sg*
LU
l-p>j
CC '<
to.
o<
O
0.00 0.40 0'.80 I'.ZO 1.60 Z'.OO
CONCENTRflTION HS (MG/L)
Figure 2. Cumulative distribution of individual plant median
arsenic concentrations.
515
-------
o
D
0.18 0.36 0.54 0.72
CONCENTRfiTION CD IMG/L)
0.30
Figure 3. Cumulative distribution of individual plant median
cadmium concentrations.
516
-------
o
o
0.01 0.02 0.03 0.04-
CONCENTRRT30N flS (MG/L)
0.05
Figure 4. Cumulative distribution of individual plant median
arsenic concentrations after deletion of the four
highest values.
517
-------
o
o
O.02 0.05 0.07 0.10
CONCENTRflTION CD (MG/L)
0.12
Figure 5. Cumulative distribution of individual plant median
cadmium concentrations after deletion of the four
highest values.
-------
-------
o
o
CJ3
20.00 40-00 60.00 80.00
'/. INDUSTR]flL BY FLOW
100.00
Figure 7. Distribution of individual plant median zinc concentra-
tions as a function of individual contribution to total
plant flow.
520
-------
SOURCES AND FLOW OF HEAVY METALS,AND CYANIDE
IN THE KOKOMO MUNICIPAL TREATMENT SYSTEM
K. J. Yost, T. G. Adams and R. F. Wukasch
Purdue University
West Lafayette, Indiana
INTRODUCTION
The objective of this study was to establish a protocol to assist com-
munities in identifying, quantifying, and formulating regulatory policies for
reduction of heavy metal and cyanide discharges to publicly owned treatment
works (POTW) to the point that land disposal of sludge is feasible.
Establishment of a routine to obtain representative samples from likely
metals and cyanide sources (nonpoint, point, and street surface) was of pri-
mary importance. This involved determining sampling station locations and
sampling frequencies for point source and trunkline monitoring. The final
concern was establishment of pretreatment strategy alternatives to reduce
metal and cyanide inputs to the sewer network of a representative city to
levels consistent with land disposal of digester sludge. The control strat-
egy evolved during the study may be implemented by imposing, or modifying
existing city ordinances which limit concentrations of trace metals and
cyanide in industrial waste discharged to the sewer network.
The prototype community selected for this study was Kokomo, Indiana.
It is a medium-sized city (42,000) with (from the sampling and analysis point
of view) a manageably sized combined sanitary and storm sewer treatment net-
work which serves well-defined residential areas and a diverse industrial
community. The industrial and commercial makeup of Kokomo includes such in-
dustrial categories as electroplating, metal fabricating, automotive manu-
facture, chemical processing, and food processing.
Kokomo was chosen for the study for several reasons. Sewer system net-
works of large cities are so complex that they virtually defy definitive flow
analysis and/or quantitative source identification. Samller communities tend
to have atypical residential-industrial flow compositions. Kokomo provided
a wastewater flow mixture typical of an industrialized city (i.e., one that
has neither an over-abundance nor a paucity of domestic or industrial sources
discharging to the sewer network).
The treatment facility which serves the city of Kokomo is a newly reno-
vated 30 MGD (million gallons per day) activated sludge multimedia gravity
-------
filter plant. The sewer system is composed of six major trunklines serving
the city and surrounding areas. Three of these trunklines are classified as
purely residential, while the other three carry a combination of residential,
commercial, and industrial wastewater. The city layout is such that the
northern section (older part) is served by a combination storm and sanitary
collection network, with overflows going to Wildcat Greek. The southern sec-
tion of the city (new part) is served by a separate storm and sanitary col-
lection system. Storm water is discharged to the Wildcat and Kokomo creeks.
SAMPLING PROTOCOL
Trunkline sampling was conducted from April, 1978, to June, 1979, at
twelve locations in the Kokomo sewer network (Figure 1). These locations
were chosen to characterize metal and cyanide input to the treatment plant.
Automatic sequential samplers (ISCO-1680)-'- and continuous flow recorders
(Stevens F-68)2 were used at each sampling location to measure metal and
cyanide mass -flow, rates.
Samples were obtained for each trunkline at 2-hour intervals for three
24-hour periods. Sampling was conducted on a Monday through Thursday sched-
ule, when feasible, to avoid any unusual fluctuations in flow or metal and
cyanide discharge due to variations in industrial work schedules or increased
residential activity during the weekend. Flow rates were determined using a
combination of continuous flow recorders and sharp-crested weirs.
One of the most critical steps in any sewer monitoring program is the
selection of appropriate sampling site locations. An appropriate sampling
site is one which provides: (1) easy accessibility to and from the site,
(2) sufficient space to construct sampling and flow recording equipment, (3)
a suitable location with little or no slope and a straight section of the
sewer to obtain accurate sampling and flow data, and (4) a critical point in
the collection system for quantification of flow and pollutants. Site selec-
tion during the study was difficult. Most problems involved insufficient
space for sampling and flow recording equipment and/or sloped sewers with no
straight sections in which proper weir construction was possible.
Metal samples were collected in 500 ml acid-washed polyethylene bottles
pre-preserved with 2 ml of 1:1 redistilled nitric acid. Samples were ana-
lyzed with a Perkin-Elmer Model 5000 atomic absorption spectrophotometer.
Cyanide analyses were conducted as specified in Methods for Chemical Analysis
of Water and Wastes, 1974. Samples were collected in 500 ml acid-washed
polyethylene bottles to which 2 ml of 10 N NaOH and 10 ml of 3 percent acid
were added prior to collection. The sequential samplers used to collect
cyanide wastes were packed with ice to maintain an approximately 4° C envi-
ronment prior to refrigeration. Samples were in general analyzed within
twenty-four hours of collection.
POINT SOURCE TESTING
The quantification of metal and cyanide input from specific industries
to the Kokomo sewage treatment plant yielded a data base which operators of
other publicly owned treatment works (POTW) may utilize to estimate metal and
522
-------
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(South Northside INT)T.
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-------
cyanide input to their particular collection systems. Where treatment was
practiced, sampling raw and treated wastes of point sources discharging to
the Kokomo system may provide information on degrees of pollutant removal
which are feasible for the types of industries surveyed here. This informa-
tion may in turn be useful for determining technologically feasible discharge
limits for these industrial categories which reduce heavy metal and cyanide
levels in sludge to the point that land disposal of sludge is feasible.
Twelve known point sources of heavy metals and cyanide identified by
Standard Industrial Classifications (SIC) were sampled in this study over a
3-month period in 1979 (see Figure 1). Flow data from these point sources
were obtained from flow meters and/or city water meters available at each
one. In one case, a pair of V-notch weirs with a recording depth-of-flow
indicator (Stevens flow recorder and float) was employed to measure flow
above and below the point of discharge.
Sampling, at each source was conducted at 2-hour intervals for 24 hours
over a consecutive three-day period. Metal and cyanide samples were col-
lected using an automatic sequential sampler (ISCO). The treatment and anal-
ysis of these samples are described elsewhere in this report.
POINT SOURCES
Point Source 1 is a major manufacturer of automatic transmissions and
aluminum die castings for the automotive industry. Over 9,000 transmissions
are produced daily.
Effluent wastes from the transmission plant and die cast plant are col-
lected in a common receiving pit for solids settling. Overflow from the
receiving pits is transferred to batch tanks. Underflow (solids) is trans-
ported to an approved landfill for disposal. Treated effluent from the batch
tank is discharged to the Kokomo sanitation network. The final effluent from
Point Source 1 is presented in Table 1.
Point Source 2 conducts circuit board plating operations as well as some
soldering and assembling of radio components. The treatment facilities at
Point Source 2 are primarily intended to treat electroplating effluents. All
process waste from the circuit board plating operations goes to batch treat-
ment facilities where metal-bearing and dilute cyanide-bearing wastes are
treated separately. Metals waste treatment consists of pH adjustment and
precipitation, primarily as hydroxides. A pH of 9.0 is maintained in the
clarifier. Cyanide waste treatment consists of two-phase destruction of cya-
nide to carbon dioxide and nitrogen gases. This process utilizes sodium hy-
droxide to raise the pH to 10.5, while adding chlorine gas in the recircula-
tion line. The pH is reduced to 8.5 and chlorine added until cyanide de-
struction is complete. After treatment, effluent from the metal waste and
cyanide waste tanks is pumped into a waste blending tank (30,000 gal). The
effluent of Point Source 2 is presented in Table 2.
Point Source 3 manufactures various radios and radio parts, as well as
semiconductor components. Other products include digital controls, silicon
rectifiers, and microelectronic voltage regulators. Some plating of radio
524
-------
TABLE 1. DAILY DISCHARGES OF METAL AND CYANIDE FROM POINT SOURCE 1 TO NEW
PETE'S RUN (T-3) TRUNKLINE.
Day 1
Day 2
Day 3
Mean
S.D.
Effluent
(mgd)
0.496
0.379
0.446
0.440
0.059
Pounds Per Day
Cd
0.006
0.004
0.004
0.005
0.001
Cr
0.034
0.018
0,048
0.033
0.015
Ni
0.28
0.16
0.21
0.22
0.06
Pb
0.14
0.088
0.080
0.10
0.03
' Zn
3.02
1.32
1.40
1.91
0.96
Cu
0,20
0.16
0.44
0.27
0.15
CN-
<0.42
<0.33
<0.38
<0.38
0.05
TABLE 2. DAILY DISCHARGES OF METAL AND CYANIDE FROM POINT SOURCE 2 TO NEW PETE'S
RUN (T-3) TRUNKLINE.
Effluent
(mgd)
Day 1
Day 2
Day 3
Mean
S.D.
0
0
0
0
0
.720
.270
.324
.438
.246
Pounds Per Day
Cd
0.19
0.044
0.054
0.096
0.082
Cr
0.11
0.032
0.034
0.058
0.045
Nl
0.19
0.034
0.034
0.086
0.090
<0
<0
<0
0
0
Pb
.078
.027
.027
.020
.029
Zn
1.15
0.26
0.38
0.60
0.49
Cu
6
2
2
3
2
.74
.16
.54
.81
.54
CN-
<0.99
<0.25
<0.28
<0.51
0.42
-------
parts is also conducted at this location. The wastewater treatment facili-
ties installed at Point Source 3 are primarily intended to treat electronic
semiconductor manufacturing and electroplating effluents. Treatment of metal
waste consists of pH adjustment and precipitation of heavy metals as hydrox-
ides. Chemical reactants for pH control are lime (cadmium hydroxide) with
sodium hydroxide as an emergency backup to raise the pH and sulfuric acid to
lower the pH. A pH of 9.0 is maintained in the clarifiers. There are three
metal waste treatment tanks, holding 1.4 million gallons each. Cyanide waste
treatment consists of a two-phase destruction of cyanide to carbon dioxide
and nitrogen gas. This is accomplished by the addition of lime to raise the
pH to 10.5, while adding chlorine gas in the recirculation line. Sodium hy-
droxide is used as a backup for the lime. The pH is reduced to 8.5 and
chlorine is added until cyanide destruction is complete. There are three
cyanide waste treatment tanks, each holding 0.19 million gallons. The final
effluent characteristics are given in Table 3.
Point Scmrce. 4 manufactures major products for the automotive, construc-
tion, and agricultural industries. Treatment facilities include a 600-gallon
chromium reduction tank equipped with pH controls, sulfuric acid, and sodium
bisulfite feed equipment and mixer, two 9,000-gallon batch neutralization
tanks equipped with pH controls, and a 50-gallon per minute continuous belt
vacuum filtration unit. These values represent a metal removal efficiency
of >99 percent for total chrome and >98 percent for zinc. Point Source 4
discharge to the Kokomo sanitary sewage system is presented in Table 4. At
the time of sampling, the chrome pretreatment unit was constructed but not in
operation.
Point Source 5 specializes in plating various manufactured products. It
provides services for both rack and barrel, plating and finishes including
cadmium, hard chromium, zinc, copper, nickel, silver, and tin plating. The
copper, zinc, cadmium, and silver plating lines utilize cyanide solutions.
No treatment of metal and cyanide wastewater is presently practiced. Efflu-
ents from plating operations are discharged directly to the Kokomo sewer net-
work, and acid and alkali baths are dumped to the city sewer once every two
weeks. The effluent from Point Source 5 is presented in Table 5.
Point Source 6 is a manufacturer of high and low carbon steel wire for
industrial and commercial use. Its products also include nails, various wire
products, fencing, and other galvanized material for farm, industrial, and
domestic use. Wastes with pollution potential emanate from (1) steel melt-
ing, (2) primary rolling, (3) secondary rolling, (4) pickling, and (5) coat-
ing facilities. The contaminants include oils, solids, chemicals, metals,
and acids. The waste treatment system of Point Source 6 includes both non-
chemical (mechanical) and chemical treatment for removing contaminants from
the mill cooling and process water. Metal and cyanide concentrations in
plant effluent are shown in Table 6.
The major product of Point Source 7 is "hot dipped" galvanized woven
chainlink fencing. No special treatment facilities exist at this location
except the batch type neutralization of etching acid. Discharge wastewater
consists of rinse from the alkaline process, quench water from the chainlink
-------
TABLE 3. DAILY DISCHARGE OF METAL AND CYANIDE FROM POINT SOURCE 3 TO NEW PETE'S
RUN (T-3) TRUNKLINE.
Day 1
Day 2
Day 3
Mean
S.D.
Effluent
(mgd)
1.549
1.539
1.944
1.677
0.231
Pounds Per
Cd
0.71
0.65
0.75
0.70
0.05
Cr
0.13
0.12
0.15
0.13
0.02
Ni
0.59
0.65
1.01
0.75
0.23
Pb
<0.13
<0.13
<0.47
<0.28
0.20
Day
Zn
17.98
44.12
30.60
30.90
13.11
Cu
3.49
5.01
5.04
4.51
0.89
CN
<1.33
2.19
<4.46
<3.55
1.67
Ln
ho
TABLE 4. DAILY DISCHARGES OF METAL AND CYANIDE FROM POINT SOURCE 4 TO WASHINGTON FEEDER
(T-4a-2) AND SUBSEQUENTLY TO THE NORTH NORTHSIDE INTERCEPTOR (T-4a).
Day 1
Day 2
Day 3
Mean
S.D.
Effluent
(mgd)
0.095
0.092
0.093
0.093
0.015
Pounds Per J)ay
Cd
<0.002
<0.002
<0.002
<0.002
0.000
Cr
<7.75
"6.24
11.97
<8.65
2.97
Ni
<0.033
<0.026
< 0.008
<0.023
0.013
Pb
<0.035
0.054
0.041
<0.043
"0.009
Zn
20.82
32.02
1.17
18.00
15.63
Cu
0.17
0.094
0,096
0.12
0.04
CN~
<0.079
<0.077
<0.078
<0.078
0.001
-------
Ln
M
CO
TABLE 5. DAILY DISCHARGES OF METAL AND CYANIDE FROM POINT SOURCE 5 TO THE
WASHINGTON FEEDER (T-4a-2) AND THE NORTH NORTHSIDE INTERCEPTOR (T-4a).
Pay I
Day 2
Day 3
Mean
S.D.
Effluent
(mgd)
0.235
0.213
0.264
0,237
0.026
Pounds Per Day
Cd
0.41
0.36
0.94
0.57
0.32
Cr
39.12
79.93
130.36
83,23
45.70
Ni
6.21
3.45
4.69
4,78
1.38
Pb
0.067
0.067
0.51
0,21
0.26
Zn
1.10
1.48
3.77
2,12
1,44
Cu
0,67
0.61
1.63
0.97
0,57
CN~
<0,45
'0.43
3.72
<1,53
1.89
TABLE 6. DAILY DISCHARGES OF METAL AND CYANIDE FROM POINT SOURCE 6 TO PETE'S RUN
INTERCEPTOR (T-5a).
Day 1
Day 2
Day 3
Mean
S.D.
Effluent
(mgd)
0.384
0.384
0.384
0.384
0.000
Pounds Per Day
Cd
0.010
<0.004
<0.008
<0.007
0.003
Cr
0.14
0.022
0.055
0.072
0.061
Ni
0.41
0.19
0.27
0.29
0.11
Pb
0.97
0.16
0.27
0.47
0.44
Zn
1104.90
210.40
239.52
518.27
508.24
Cu
0.45
0.21
0.51
0.39
0.16
CN~
<0.76
<0.32
<0.33
<0.47
0.25
-------
fencing process, and acid drippings from the etching process. Final effluent
concentrations are presented in Table 7.
Point Source 8 manufactures architectural aluminum entrances for all
types of commercial buildings. It also manufactures extruded aluminum store-
front and curtain wall systems for the commercial construction market. The
prime functions of this plant include aluminum extrusion, anodizing, and
fabrication. Wastewater discharged to the Kokomo sewage network consists of
de-ionizer regenerant solution, water softener backwash, boiler blowdown, and
anodizing rinse waters. The plant has a two-stage neutralization and equali-
zation treatment facility. Wastewater from the de-ionizers and ion exchange
regenerators is consolidated prior to discharge into an equalization tank
(10,000 gal). Sulfuric acid anodizing solution is then pumped into the
equalization tank. Anodizing rinse water and effluent from the equalization
tank are discharged into a primary neutralization tank (17,900 gal) and then
into a secondary neutralization tank (4,700 gal). Chemical feed for both
neutralization tanks consists of sodium hydroxide and sulfuric acid. Efflu-
ent from the secondary neutralization is pumped directly into the Kokomo
sanitary sewer. The water softener backwash and the boiler blowdown are not
treated. The final effluent of Point Source 8 is presented in Table 8.
Point Source 9 manufactures high performance nickel-base, cobalt-base,
and iron-base alloys in various forms and forgings. Waste treatment facili-
ties consist of a chromium reduction and clarification system. Two concrete
equalization tanks (131,000 gal each) collect wastewater from various metal
operations. This waste is then treated in a 400-gal acid mix tank with sul-
furic acid and sulfur dioxide gas. Effluent from the mix tank is pumped into
a 400-gal lime slurry reactor tank where hydrated lime is added. Discharge
from the slurry tank is then emptied into a 3,000-gal flocculator. This
waste is pumped into a 108,000-gal reactor-type clarifier. The sludge is
thickened, using a 30,000-gal sludge thickener. Supernatant from the sludge
thickener is pumped back to the equalization tank. Sludge is hauled to the
company's drying beds and eventually transported to an approved state land-
fill. Other wastes from the facility discharged to the sanitary sewer are
process water, cooling tower blowdown, boilerdown, water softener backwash,
and sanitary wastes. Effluent of Point Source 9 is presented in Table 9.
The removal efficiency of the Point Source 9 treatment system was moni-
tored for chromium, nickel, copper, and zinc. Sampling locations were chosen
to effect flow balances on major components of the treatment system. Metal
samples were collected every two hours for 24 hours over a consecutive three-
day period. Removal efficiencies for chromium, nickel, copper, and zinc are
presented in Table 10.
Point Source 10 conducts cold rolling and metal fabrication operations
of various nickel-base, cobalt-base, and iron-base alloys. Machining of the
rolled and fabricated products is also carried out at this location. There
are no pretreatment facilities. The final effluent from Point Source 10 is
presented in Table 11.
Point Source 11 provides laundry service for primarily non-commercial
customers. Approximately 9,000 pounds of laundry are serviced per day. The
529
-------
Ln
OJ
o
TABLE 7. DAILY DISCHARGES OF METAL AND CYANIDE FROM POINT SOURCE 7 TO THE WASHINGTON
FEEDER LINE (T-4a-2) AND THE NORTH NORTHSIDE INTERCEPTOR (T-4a) TRUNKLINE.
Day 1
Day 2
Day 3
Mean
S.D.
Effluent
(mgd)
0.072
0.072
0.072
0.072
0.000
Pounds Per Day
Cd
<0.001
<0.001
<0.001
<0.001
0.000
Cr
1.31
0.045
0.082
0.48
0.72
Ni
1.12
0.26
0.33
0.57
0.48
Pb
0.039
0.045
0.026
0.037
0.010
Zn
13.53
56.49
43.56
37.86
22.04
Cu
2.43
1.46
0.49
1.46
0.97
CN~
<0.060
<0.060
<0.060
<0.060
0.000
-------
TABLE 8. DAILY DISCHARGES OF METAL AND CYANIDE FROM POINT SOURCE 8 TO THE UNION FEEDER
LINE (T-Ab-1) AND THE SOUTH NORTHSIDE INTERCEPTOR (T-4b) TRUNKLINE.
Day 1
Day 2
Day 3
Mean
S.D.
Effluent
(mgd)
0.264
0.266
0.288
0.273
0.013
Pounds Per Day
Cd
<0.001
<0.001
<0.001
<0.001
0.000
Cr
0.063
0.031
0.022
0.039
0.022
Ni
0.095
<0.088
<0.028
<0.070
0.037
Pb
0.070
0.030
0.027
0.042
0.024
' Zn
0.14
2.28
1.82
1.41
1.12
Cu
0.55
0.30
0.30
0.38
0.14
CN~
<0.22
<0.22
<0.23
<0.23
0.01
Cn
Ul
TABLE 9. DAILY DISCHARGES OF METAL AND CYANIDE FROM POINT SOURCE 9 TO OLD PARK ROAD
FEEDER LINE (T-5b) AND PETE'S RUN (T-5a) TRUNKLINE.
Day 1
Day 2
Day 3
Mean
S.D.
Effluent
(mgd)
0.335
0.335
0.335
0.335
0.000
Pounds Per Day 1
Cd
<0.003
<0.003
<0.004
<0.004
0.001
Cr
0.39
0.36
0.63
0.46
0.15
Nl
8.25
11.57
5.34
8.39
3.12
Pb-
<0.028
0.028
0.028
<0.028
0.000
Zn
0.33
0.42
0.42
0.39
0.05
CU
0.16
0,26
0..28
0,23
0.05
or
<0.32
<0.28
<0.28
<0.29
0.02
-------
TABLE J.O. CONCENTRATIONS OF INFLUENT AND EFFLUENT WASTE
STREAMS AND REMOVAL EFFICIENCIES FOR POINT SOURCE
9 WASTE TREATMENT SYSTEM.
Concentration (mg/1)*
Cr Cu Ni Zn
Influent
Effluent
Mean 169. 1.91 890. 0.49
S.D. 121. 1.24 1450. 0.57
Mean 0.27 0.008 45.8 0.047
S.D. 0.41 0.018 65.70 0.196
Percent Removal
99.8 99.6 94.9 90.4
*Averaged over three-day sampling period. •
532
-------
facility also handles uniforms from various commercial and industrial opera-
tions. No treatment facilities exist at Point Source 11. All wastewater is
directly discharged to the sewer collection network. Plant effluent is pre-
sented in Table 12.
Point Source 12 specializes in printing magazines (12 to 13 million each
month), catalogs, brochures, books, and newspaper supplements. Water-base
and solvent-base inks are both used, depending on the application. The rolls
used in the printing process are both acid-etched and subsequently copper-
chrome plated and re-etched with a computer-controlled diamond stylus. -Sol-
vents, oils, and waste inks are disposed of by a company licensed for dis-
posal of organic wastes. Other effluents (boiler blowdown, water softener
regenerant) are discharged into the Kokomo sanitation network, except for the
sludge (50 gal every six months) from the chrome plating tanks, which is
hauled to the city's landfill area. Effluent values for Point Source 12 are
presented in Table 13.
COLLECTION SYSTEM MONITORING
The schematic version of the Kokomo sewer system shown in Figure 1 indi-
cates trunkline sampling points and point sources. Note that there are three
primary trunklines with no known point sources discharging to them: T-l, T-2
and T-6. Note also that T-4a receives discharges from two plating shops by
way of feeder line T-4a-2.
Wastewater samples were obtained at 2-hour intervals in major trunk and
feeder lines. Table 14 gives waste flow and metal flow summaries for the
three major trunklines feeding the treatment plant which have no identified
point sources discharging metals or cyanide to them (T-l, 2, 6). These
trunklines are defined to be "residential" in nature. Conversely, Table 15
summarizes metal and cyanide flows in trunklines receiving discharges from
identified point sources (T-3, 4a, 4b, 5a), and they are designated as "non-
residential" in this analysis. Table 16 gives average sludge cake metal con-
centrations and POTW metal removal factors for a 60-day sampling period.
Three North Northside Interceptor (Figure 1) feeder lines were sampled
for a 3-day period to further elucidate the relative metal and cyanide inputs
of a "residential" line (Indiana), a line receiving discharges from two elec-
troplating shops (Washington), and a line receiving discharge from a commer-
cial facility (Appersonway). Results of the sampling program are given in
Table 17. Note that Zn flow in the Appersonway feeder is extremely high for
Day 3. A check of laboratory worksheets has failed to uncover analytical
errors which would explain the elevated Zn flow. Trunkline samples collected
at 2-hour intervals between 6:00 p.m. and 4:00 a.m. exhibit an average Zn
concentration of almost 34 mg/1. Assuming the high concentrations are real,
the data strongly suggest the possibility that concentrated waste is being
dumped into the Appersonway Feeder.
Table 18 suggests that the Appersonway, Washington Street, and Indiana
Street feeder lines account on the average for approximately 58 percent of
the flow in the North Northside Interceptor, and from 51 percent to over 300
percent of the flow of metals and cyanide. The fact that feeder line and
533
-------
TABLE 11. DAILY DISCHARGES OF METALS AND CYANIDE FROM POINT SOURCE 10 TO OLD PARK ROAD
FEEDER LINE (T-5b) and PETE'S RUN (T-5a) TRUNKLINE.
Day 1
Day 2
Day 3
Mean
S.D. '
Effluent
(mgd)
— *
0.058
0.058
0.058
0.000
Pounds Per Day
Cd
<0.001
0.001
<0.001
0.000
Cr
0.008
0.020
0.014
0.008
Ni
0.10
0.12
0.11
0.01
Pb
<0.005
<0.003
<0.004
0.001
' Zn
0.56
1.28
0.92
0.51
Cu
0.030
0.054
0.042
0.017
CN-
<0.048
<0.048
<0.048
0.000
TABLE 12. DAILY DISCHARGES OF METAL AND CYANIDE FROM POINT SOURCE 11 TO THE APPERSON
FEEDER LINE (T-4a-3) AND THE NORTH NORTHSIDE INTERCEPTOR (T-4a).
Day 1
Day 2
Day 3
Mean
S.D.
Effluent
(mgd)
0.0445
0.0288
0.0397
0.0377
0.0080
Pounds Per Day
Cd
0.005
0.004
0.003
0.004
0.001
Cr
0.007
0.003
0.011
<0.007
0.004
Nl
0.006
0.006
0.008
0.006
0.002
Pb
0.20
0.50
0.22
0.31
0.17
Zn
0.19
0.11
0.17
0.16
0.04
Cu
0.088
0.073
0.13
0.097
0.031
CbT
<0.041
<0.024
<0.095
<0.053
0.037
-------
TABLE 13. DAILY DISCHARGES OF METAL AND CYANIDE FROM POINT SOURCE 12 TO THE SOUTH
NORTHSIDE INTERCEPTOR (T-4b) TRUNKLINE.
Day 1
Day 2
Day 3
Mean
S.D.
Effluent
(mgd)
0.144
0.204
0,205
0.184
0.035
Pounds Per Day
Cd
<0.002
<0.002
<0.002
<0.002
0.000
Cr
1.95
7.29
5.38
4.87
2.71
Ni
<0.012
<0.017
<0.018
<0.016
0.003
Pb
0.041
0.084
0,085
0.070
0.025
Zn
0.069
0.083
0,065
0.072
0.009
Cu
2.91
12.32
19,20
11.48
8.18
CN~
<0.12
<0.17
<0.18
<0.16
0.03
-------
TABLE 14. RESIDENTIAL INPUTS OF METAL ASP CYANIDE TO KOKOMO POTW.
Sampling Trunkline
Day Flow (mgd)
Pounds Per Day
Cd
Cr
Ni
Pb
Zn
Cu
OT
Diaeon Road (T-l)
1
2
3
Mean
S.D.
Fayble (T-2)
1
2
3
4
Mean
S.D.
0.380
0.478
0.406
0.421
0.051
0.273
0.661
0.731
0.867
0.633
0.255
Northwest Interceptor
1
2
3
Mean
S.D.
Sum of
Daily Means
0.148
0.086
0.061
0.098
0.045
1.152
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
0.010
0.027
0.007
0.011
0.011
(T-4)
0.001
0.003
<0.001
0.002
0.001
0.013
0.022
0.008
0.014
0.015
0.007
0.016
0.082
0.28
0.15
0.13
0.11
0.002
0.001
<0.001
0.001
0.001
0.146
0.021
0.004
0.029
0.018
0.013
0.015
0.053
0.15
0.072
0.073
0.057
0.004
0.002
0.002
0.003
0.001
0.94
0.052
0.016
0.023
0.030
0.019
0.01
0.15
0.37
0.18
0.18
0.15
0.012
0.005
0.003
0.007
0.005
0.217
0.30
0.16
0.16
0.21
0.08
0.40
0.44
17.37
3.34
5.39
8.11
0.095
0.041
0.018
0.051
0.040
5.65
0.14
0.11
0.14
0.13
0.02
0.31
1.11
1.94
1.18
1.14
0.67
0.079
0.006
0.018
0.034
0.039
1.30
0.015
0.011
0.015
0.013
0.002
0.029
0.031
1.26
0.083
0.35
0.61
0.007
0.006
0.003
0.005
0.002
0.368
536
-------
TABLE 15. NONRESIDENTIAL INPUTS OF METAL AND CYANIDE TO KOKOMO POTW.
Sampling Trunkline
Day Flow (mgd)'
Pounds Per Day
Cd
Cr
North Northside Interceptor (T-4a)
1 3.76 5.0 33.0
2 6.18 5.2 51.0
3 3.99 2.2 30.0
Mean 4. 64 4.3 40.0
S.D. 1.92 2.3 11.0
Ni
5.5
5.5
3.6
5.1
0.92
Pb
0.65
4.6
0.71
2.4
1.9
Zn
57.0
77.0
45.0
62.0
13.0
Cu
3.1
6.9
2.5
4.6
2.0
CN"
1.5
2.9
1.4
2.1
0.71
South Northside Interceptor (T-4b)
1
2
3
Mean
S.D.
Pete's Run
1
2
3
Mean
S.D.
New Pete's
1
2
3
Mean
S.D.
Sum of
Daily Means
0.854
0.903
0.829
0.862
0.053
Interceptor
1.53
0.961
1.33
1.27
0.23
0.006
0.001
0.011
0.006
0.003
(T-5a)
0.067
0.044
0.018
0.043
0.02
0.416
0.165
0.14
0.240
0.125
0.24
0.23
0.18
0.32
0.03
0.058
0.087
0.045
0.063
0.018
0.85
0.45
0.95
0.75
0.22
0.120
0.069
0.086
0.092
0.021
0.54
0.56
0.80
0.63
0.12
2.27
11.90
2.37
4.52
5.51
6.86
5.4
2.6
4.95
1.8
l;61
1.02
0.61
1.08
0.410
2.98
1.7
2.9
2.5
0.59
0.089
0.013
0.024
0.042
0.034
0.4
0.1
0.07
0.19
0.15
Run Interceptor (T-3)
3.057
2.628
2.286
2.657
0.386
9.43
3.62
3.12
2.62
3.12
0.50
0.22
0.99
2.52
1.24
1.17
7.28 40.0
3.99
3.07
2.52
3.56
0.46
9.27
0.33
0.30
0.26
0.30
0.04
3.0
14.47
8.96
6.38
9.94
4.13
80.2
15.82
9.11
9.06
11.33
3.89
19.3
9.07
5.09
3.35
5.84
2.93
8.02
537
-------
TABLE 16. AVERAGE METAL CONCENTRATIONS IN KOKOMO POTW SLUDGE CARS- AND
OVERALL PLANT METAL REMOVAL FACTORS FOR A 60-DAY SAMPLING PERIOD.
C4 Cr Cu Ni Zn
Avg. Metal Concentration (mg/kg) 380 1060 1800 530 13600
Plant Removal Factor (Z) 80.3 97.9 85.0 29.4 83.7
TABLE 17. DAILY AVERAGE METAL AND CYANIDE FLOWS IN THREE NORTH NORTHSIDE
INTERCEPTOR FEEDER LINES.
Sampling Trunk-Line
Day Flow (mgd)
Pounds Par Day
Cd
Cr
Ni
Pb
Zn
Cu
or
Appersonway Feeder Line
1
2
3
M^gq
S.D.
0.
0.
0.
0.
0.
Washington Street
1
2
3
Mean
S.D.
Indiana Street
1
2
3
Mean
S.D.
Sum of
Daily Means
1.
1.
1.
1.
0.
364
852
303
340
032
Feeder
553
575
648
592
050
0.013
0.036
0.029
0.028
C.009
2.25
1.54
2.63
2.16
0.58
0
0
0
0
0
35
38
28
34
5
.042
.70
.15
.30
.35
.89
.35
.22
.32
.49
0.73
0.50
0.65
0.64
0.14
1.33
2.61
4.32
2.92
1.27
0.097
0.095
0.083
0.092
0.008
0.21
0.19
0.33
0.24
0.08
2.45
2.67
110.09
38.40
62.08
87.91
30.74
. 38.66
52.44
30.97
0
0
0
0
0
3
2
13
6
5
.27
.42
.23
.31
.10
.23
.64
.05
.31
.85
0.043
0.034
<0.001
0.025
0.023
2.26
1.08
16.13
6.49
8.37
Feeder Line
0.
0.
0.
0.
0.
2.
208
220
314
247
053
68
0.006
0.001
0.001
0.008
0.003
2.19
0
0
0
0
0
34
.091
.005
.13
.075
.064
.7
0.007
0.007
0.038
0.034
0.047
3.59
0.005
0.025
0.045
0.025
0.020
0.357
5.37
0.40
3.38
3.05
2.50
93.9
0
- 0
18
6
10
12
.070
.081
.53
.23
.65
.9
<0.001
0.010
0.010
0.006
0.006
6.52
538
-------
TABLE 18. FRACTIONS OF WASTEWATER, METALS AND CYANIDE FLOWS IN NORTH
NORTHSIDE INTERCEPTOR ATTRIBUTABLE TO APPERSONWAY,
WASHINGTON STREET, AND INDIANA STREET FEEDERS.*
_ , _, Pounds Per Day
Total Flow : i :
(mgd) Cd Cr Nl Pb Zn Cu CN~
0.58 0.51 0.87 0.70 0.15 1.51 2.8 3.1
Estimates based on nonsimultaneous sampling of trunk and feeder lines.
-------
trunkline sampling was not done simultaneously evidently accounts for the
>100 percent entries in Table 17. The aforementioned anomalous high Zn flow
on Day 3 of the Appersonway sampling period, together with high Zn flows in
the Washington feeder line which serves two electroplating shops, constitute
92 percent of the combined feeder line Zn flow to the North Northside Inter-
ceptor. It can be seen from Tables 4 and 5 that the sum of the Zn discharges
from the two electroplating facilities is 221.3 Ibs/day for the respective
sampling periods. This represents only 41 percent of the Zn flow found in
the Washington feeder line during the sampling period. Thus either the two
plating facilities were discharging substantially more Zn during the feeder-
line sampling period than during the point source sampling periods, or there
is a substantial discharge of Zn from one or more unidentified sources.
A mechanism other than comparison of overall mean flow rates can be used
to estimate whether or not measured sources of metals and cyanide account for
flows observed in a receiving trunkline. This method involves constructing
all possible-combinations of daily average flows from measured sources for
the purpose of determining likely pollutant flow limits in a receiving trunk-
line. For example, assume there are three sources feeding a trunkline whose
discharges have been measured (nonsimultaneously) for three days each. There
are then nine possible combinations of daily averages that may be constructed
If it is assumed that discharges from the three sources are not correlated
(i.e. there are no process variables or maintenance practices keyed to par-
ticular days of the week, etc.), the upper and lower flow limits resulting
from the nine possible daily average discharge combinations may be inter-
preted as measures of the flow limits likely to be seen in a receiving trunk-
line. This approach is referred to here as the method of "random superposi-
tion." Its application to the three feeder lines to the North Northside
Interceptor is given in Table 19. Note that while the mean Ni flow from the
three feeders represents only 70 percent of the mean interceptor flow, the
random superposition upper limit feeder flow is 94 percent of the interceptor
upper limit. This suggests that the three feeders may account for enough of
the interceptor Ni flow that supplementary sampling would not be required to
identify Ni point sources upstream from the feeder-interceptor junctions.
A comparison of Tables 4, 5, and 17 indicates that the sum of the mean
daily Cu and CN discharges from the two plating facilities accounts for only
24 percent of both the Cu and CN flow in the Washington feeder line. This
suggests the possibility of unidentified sources of Cu and CN. However,
Table 17 indicates that for two of the three sampling days, the mean Cu and
CN flows are, respectively, 2.9 and 1.7 pounds/day. This compares in magni-
tude to the sum of the Cu and CN discharges from Point Sources 4 and 5. The
bulk of the mean Cu and CN flows in the Washington feeder derive from high
flows on Day 3. Since the other metals do not exhibit marked relative in-
creases for Day 3, this suggests the discarding of concentrated Cu-CN plating
waste, probably from Point Source 5, was an alternative explanation to un-
identified sources discharging to the Washington feeder.
Point Sources 1, 2, and 3 discharge to the New Pete's Run trunkline (T-3).
Table 20 gives the fractions of total flow, metals, and cyanide in New Pete's
Run represented by the sum of the mean daily discharges from these three
point sources, as given in Tables 1, 2, and 3. It suggests the possibility
540
-------
TABLE 19. RANDOM SUPERPOSITION FLOW LIMITS FOR METALS AND CYANIDE
INCOMEINED APPERSONWAY, WASHINGTON STREET, AND INDIANA
STREET FEEDERS.
---" - Flow Limits (Ibs/day)
Combined Feeders
North Northside Int.
Parameter
Upper
Lower
Upper
Lower
Cd
Cr
Ni
Pb
Zn
Cu
or
2.72
39.7
5.19
0.47
203.0
32.0
16.2
" r.56
28.3
2.34
0.28
33.6
2.94
1.08
5.2-
51.0
5.5
4.6
77.0
6.9
2.9
2.2
30.0
3.6
0.65
45.0
2.5
1.4
TABLE 20. FRACTIONS OF WASTEWATER, METALS, AND CYANIDE FLOWS IN NEW
PETE'S RUN TRUNKLINE ATTRIBUTABLE TO POINT SOURCES 1, 2,
AND 3.
Total Flow
(mgd)
0.96
Pounds Per Day
Cd
0.26
Cr
0.18
Ni
0.30
Pb
0.83
Zn
3.4
Cu
0.76
CN"
0.51
Based on nonsiiaultaneous sampling of point sources and trunkline.
TABLE- 21. RANDOM SUPERPOSITION FLOW LIMITS FOR METALS AND
CYANIDE IN COMBINED POINT SOURCES 4, 5, AND 7
EFFLUENT.
Flow Limits (Ibs/day)
Parameter
Combined Sources
Upper
Lower
Washington Feeder
Upper Lower
Cd
Cr
Ni
Pb
Zn
Cu
QT
0.94
143.0
7.36
0.61
92.3
4.23
.038
0.36
45.4
3.72
0.12
15.8
1.25
.030
2.68
38.9
4.32
0.33
87.9
13.1
16.3
1.54
28.2
1.83
0.19
30.7
2.64
1.08
541
-------
TABLE 22. RANDOM SUPERPOSITION PLOW LIMITS FOR METALS AND
CYANIDE IN COMBINED POINT SOURCES 9 AND 10
EFFLUENT.
Parameter
Cd
Cr
Ni
Pb
Zn
Cu
or
Combined
Upper
0.0025
0.65
11.7
0.033
1.7
0.33
0.19
Flow Limits
Sources
Lower
0.002
0.37
5.44
0.031
0.89
0.19
0.16
(Ibs/day)
Pete's
Upper
0.067
0.24
0.95
0.30
6.86
2.98
0.40
-Run Int.
Lower
0.018
0.18
0.45
0.54
2.6
1.7
0.072
TABLE 23. RANDOM SUPERPOSITION FLOW LIMITS FOR METALS AND CYANIDE
IN COMBINED POINT SOURCES 8 AND 12 EFFLUENT.
Flow Limits (Igs/day)
Parameter
Cd
Cr
Ni
Pb
Zn
Cu
CN~
Combined
Upper
0.0015
7.35
0.11
0.16
2.36
19.8
0.21
Sources
Lower
0.0015
1.98
0.02
0.068
0.21
3.2
0.17
South Northside
Upper
0.011
0.416
0.087
0.12
11.9
1.61
0.089
Int.
Lower
0.001
0.14
0.045
0.069
2.27
0.61
0.013
-------
of other (unidentified) point sources discharging Cd, Cr, Ni, and NC to the
trunkline. The high mean Cr flow in New Pete's Run is primarily the result
of an extremely high flow on one of the three days the trunkline was sampled.
An alternative hypothesis (to an unidentified point source) could be a break-
down of the Point Source 3 Cr treatment system during trunkline sampling.
Tables 21, 22, and 23 give point source random superposition flow limit
comparisons for the Washington Street Feeder, Pete's Run Interceptor, and
South Northside Interceptor, respectively. The Washington Street Feeder re-
ceives discharges from two electroplating shops (Point Sources 4 and 5) and
a Zn galvanized fence production facility. Once again, the superimposed
maximum and minimum point source Cd discharge rates are substantially lower
than the observed feeder line flow limits. The relatively high Cu and CN
feeder line flows may be due to a batch dump of a Cu-CN plating solution
during Day 3 (Table 17). The Pete's Run point source-trunkline flow limit
comparison indicates that interceptor Zn and Cu flows are not accounted for
by Point Sources ~9 and 10 combined discharges. The high Ni discharge is from
Point Source 9, evidently related to the production of Ni-based alloys during
the sampling period. Finally, the South Northside Interceptor-point source
flow comparison indicates that all interceptor metal flows, except Zn, are
accounted for by Point Sources 8 and 12. Inspection of Table 8 indicates a
significant and highly variable Zn discharge from Point Source 8. This sug-
gests that the high interceptor Zn flows may result from a process solution
batch dump or markedly increased production activity at Point Source 8 during
Day 2 of interceptor sampling (Table 2).
543
-------
PB83-142463
PROBLEMS WITH METALS IN THE RESIDUE FROM COMBINED
MUNICIPAL/INDUSTRIAL WASTE TREATMENT
H. M. Jeffus
Civil Engineering Department
University of Arkansas
Fayetteville, Arkansas 72701
ABSTRACT
Metals occur in the wastewater from many industrial processes. There
are also some notable examples of metals in wastewater from municipal
residential areas. These metals tend to concentrate in the residue from
waster treatment. The disposal of this residue requires careful planning
and monitoring if adverse consequences are to be avoided later. Metals
limit biological treatment and disposal alternatives. Alternatives for
disposal are: burial, landspreading, incineration, and encapsulation with
subsequent burial.
Burial imposes a potential problem of contamination of groundwater.
Careful consideration must be given to potentially hazardous metals that
become more mobile in a reducing environment.
Landspreading imposes the potential problem with metals that are
phyto-toxic or those metals that may enter the food chain. Some metals
of concern translocate to the grain of the plant. Others are concentrated
in the root structure, which may be the edible portion of the plant.
Incineration temperature will volatilize some metals. Cadmium,
Mercury, Selenium and Zinc boil at temperatures below normal incineration
temperature.
Encapsulation is an expensive process due to the cost of the encap-
sulating material and the extra handling that is required for encapsulation.
The encapsulated material must then be stored or buried.
INTRODUCTION
Metals occur in the wastewater from many industrial processes.
Notable among such processes are metal treating and finishing wastes. Such
wastes are likely to be the major source of environmental release of Cad-
mium, Chromium, Cobalt, Copper, Molybdenum, Nickel, Titanium, Vanadium
and Zinc. For example, approximately 60% of all Cadmium used is in the
544
-------
electroplating industry. However, almost all metals have multiple uses
and the sources of metals in wastewater are many.
There are also some documented cases in cities, such as Buffalo and
Chicago, where the metal concentration in wastewater from residential areas
is quite high. These metals are apparently originating from appliances and
plumbing in residences.
The metals in wastewater tend to concentrate in the residue from
waste treatment. Table 1 shows the relative magnitude of concentration" in
an activated sludge unit treating the waste from a plant producing organic
chemicals and plastics. Table 2 shows evidence of concentration in the
bottom sediment of an aerated lagoon treating the waste from a plant pro-
ducing organic chemicals and plastics.
The disposal of these residue requires careful planning and monitoring
if adverse environmental consequences are to be avoided. Metals limit
treatment and disposal alternatives. This is particularly true with high
concentrations of the more toxic materials.
Ideally, control of metal at the point of discharge would alleviate
more than one problem. The conservation, recovery and reuse of metals
should also be factors considered in addition to pollutional considerations.
There is an insufficient quantity of several metals in known world reserves
to last 50 years at present usage. Additionally, world per capita con-
sumption cannot be raised to the level of consumption in the United States.
The United States consumption of the world's production of certain metals
exceeded the following percentages: Aluminium - 46%, Antimony - 21%,
Cadmium - 34%, Chromium - 16%, Cobalt - 16%, Copper - 25%, and Zinc - 29%.(1)
METAL CONCENTRATION
As previously mentioned, metals in the influent to a biological
treatment system are concentrated in the sludge produced. Activated
sludge systems may be more proficient in concentrating metals than other
systems; however, this is not conclusively proven as yet. Many investi-
gators have reported concentration of metals in residue with widely
varying percentages of removal and varying metal concentrations in the
sludge. (2,3) The efficiency of removal and the relative accumulation
in the sludge is probably a function of many parameters of which only a
few are understood at present.
The problem to be addressed here is what to do with this residue.
Four alternatives are: burial, landspreading, incineration and encap-
sulation with subsequent burial.
BURIAL
Burial of sludges containing high metal concentrations poses the
problem of groundwater contamination. A recent study of industrial waste
disposal landfills showed 49 of 50 sites studied had migration of metals (4).
These xjere old sites and site preparation may not have been proper,
545
-------
BLE 1 . Metal Concentrations
Plant 1.
Metal
Arsenic
Selenium
Cadmium
Beryllium
Copper
Antimony
Chromium
Nickel
Zinc
Silver
Thallium
Lead
Mercury
Organics
Influent
yg/i
12
<10
<3
3
160
<10
650
81
770
<10
<10
10
<1.0
and Plastics
Return Sludge
yg/i
200
<10
48
11
4,000
<10
18,000
3,900
15,000
13
<10
530
<5.0
TABLE 2.
Plant
Metal
Arsenic
Selenium
Cadmium
Beryllium
Copper
Antimony
Chromium
Nickel
Zinc
Silver
Thallium
Lead
Mercury
Metal Conc'entrations
2. Organics
Influent
Pg/1
17
11
2
<3
1,100
<10
1,400
1,600
2,000
<10
<10
380'
<0.1
and Plastics
Bottom Sediment
pg/Kg. Dry Wt.
10,000
<930
670
1,300
360,000
<970
250,000
1,400,000
420,000
<880
<880
30,000
3
-------
The integrity of a landfill is extremely site specific. The type of
soil, annual rainfall and annual runoff, depth to groundwater, depth to
bedrock, impermeable strata, etc., all affect the suitability of a site. In
most cases, a landfill will have to be sealed at the bottom to prevent
excessive leaching of potentially toxic metals to groundwater. Additionally,
most metals are more soluble under acid conditions that will likely prevail
in the anaerobic conditions of a landfill.
Another problem that may occur after burial is the possibility of
methane accumulating in large, potentially explosive quantities that create
hazardous situations.
LANDSPREADING
Landspreading of municipal sludges is becoming more common in the
United States. Where conditions are favorable, landspreading of combined
municipal/industrial sludges is probably the preferred disposal technique.
Favorable conditions exist when the soil, the sludge, the vegetative
cover, erosion and leaching, and access to the area can all be controlled.
Before landspreading is begun, cation exchange capacity should be
determined and a metal analysis should be made of the soil. Metal analyses
of the sludge should be made periodically to ascertain the additions to the
soil. Then semiannual analyses should be continued to prevent excessive
build-up in the soil.
One ug/g in the soil is approximately two pounds per acre. One hun-
dred short tons with a content of 100 ug/g is equal to 10 mg/1 when incor-
porated in the top 15 cm of soil. (This assumes the weight of the soil
in the top 15 centimeters is two million pounds per acre.) Table 3 gives
maximum metal concentrations found in natural soils (for selected metals).
It is recommended that metal concentrations in the soil not be allowed
to exceed these values due to sludge addition.
The vegetative cover should be carefully chosen to minimize the
possibility of certain metals entering the food chain. Some crops tend
to concentrate certain metals in the vegetative portion of the plant
whereas others tend to concentrate the metal in the grain. For example,
corn tends to exclude metals from the grain relative to soybeans, which
tend to concentrate metals in the bean. Different varieties of the same
plant often act differently. Certain metals, such as arsenic, concentrate
in the root structure. Therefore, specialists in soil science and agronomy
should be consulted to assist in determining a suitable soil-vegetative cover
combination. The Soil Conservative Service and the County Extension Service
may be most helpful in these matters.
Landspreading should not be practiced in areas with shallow soils over
carbonate rock. Landspreading of residues in such areas will contaminate
groundwater with metals, nitrates and organic matter. The author has
investigated several areas where 80 percent of the individual wells are
contaminated due to contaminant entrance to groundwater through linears in
the underlying carbonate formation.
547
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TABLE 3. MAXIMUM CONCENTRATION OF SELECTED METALS FOUND IN SOILS
Maximum
Concentration
Metal pg/g
Arsenic
Barium
Boron
Cadmium
Chromium
Cobalt
Copper
Lead
Manganese
Mercury
Molybdenum
Nickel
Selenium
Silver
Tin
Vanadium
Zinc
40
3000
100
7
3000
40
100
500
4000
0.6
5
1000
2
5
400
500
300
548
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INCINEEATION
Incineration has two adverse effects insofar as metals are concerned.
One adverse effect is the venting of those metals that have boiling temper-
ature of incineration. The other adverse effect is concentration of the
metals in the remaining ash.
Arsenic sublimes at 615 C. Cadmium, Mercury, Selenium, Sodium and
Zinc boil at temperatures less than normal incineration temperatures.
Therefore, if these metals are present in the residue, they, will appea'r in
the exhaust gas. Present values of approximately 41 grams of volatile
matter destroyed per cubic meter of exhaust gas implies that the allowable
concentration of the aforementioned metals in the residue must be extremely
small to prevent exceeding the suggested allowable concentration of these
metals in the exhaust gas. Most standards are in the range of 1 to 1.5
micrograms per cubic meter of exhaust gas.
The ash remaining after incineration will have metal concentrations
of those metals that do not vent three to four times the level in the
residue before incineration. This assumes at 65 to 75 percent volatile
solids content in the residue.
ENCAPSULATION
Encapsulation involves encasing the waste with an impermeable,
durable material that will prevent leaching of the undesirable constituents.
Suggested materials are polyethylene and asphalt. This is not chemical
fixation. Chemical fixation has not been completely satisfactory.
Encapsulation is a very expensive process and will probably only be
used when the metals are very toxic and cannot be reclaimed. The encapsu-
lated material must be either stored or buried, preferably in a sealed
landfill where groundwater could never come into contact with the encapsu-
lating material.
REFERENCES
(1) Bureau of Mines, Minerals Yearbook: Volume I, Metals, Minerals, and
Fuels; Volume II, Area Reports - International, U.S. Department of the
Interior, 1972, 1102 pp.
(2) Ching, Ming H. et al., Heavy Metals Uptake by Activated Sludge, Journal
of the Water Pollution Control Federation, Volume 47, No. 2, February
1975, pp. 362-375.
(3) Neufeld, Ronald D. and Hermann, Edward R., Heavy Metal Removal by
Acclimated Activated Sludge, Journal of the Water Pollution Control
Federation, Volume 47, No. 2, February 1975, pp. 310-329.
549
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Geraghty and Miller, Inc., The Prevalence of Subsurface Migration of
Hazardous Chemical Substances at Selected Industrial Waste Land Disposal
Sites, EPA 625/77-1-008, U. S. Environmental Protection Agency,
Washington, D. C., 1977.
550
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