^tXEAKh
Advances in
Storm and Combined Sewer
Pollution Control Abatement
ENVIRONMENTAL PROTECTION AGENCY • RESEARCH & MONITORING

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ADVANCES IN STORM AND COMBINED
SEWER POLLUTION ABATEMENT TECHNOLOGY*
by
Allen Cywin and William A. Rosenkranz**
* Presented, at the bth Annual Conference of the Water Pollution Control
Federation, San Francisco, California, October 3-8, 1971.
** Messrs. Cywin and Rosenkranz are, respectively, Deputy Director,
Technology Division and Chief, Municipal Technology Branch of the
Office of Research and Monitoring, Environmental Protection Agency.

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ABSTRACT
Research, development and demonstration efforts sponsored by the
Environmental Protection Agency since 1966 have resulted in advances
in technology which can be applied as alternatives to sewer separation
for abating pollution from combined sewers. The overall problem is
caused by basic deficiencies in collection, transport and treatment
systems, which must be corrected to provide truly efficient sewerage
facilities. All the sewerage facilities (the system) must be evaluated
in order to plan modifications which will provide the capability to
adequately control and treat wastewaters during and immediately following
storm events.
Control facilities such as in and off-system storage, flow regulation
and routing, remote flow-sensing and control, coupled with treatment,
are applicable solutions. Physical, chemical, biological and
physical-chemical treatment methods are under investigation, with a
screening, dissolved-air flotation process and a high-rate multi-media
filtration process offering the best current potential for producing
good quality effluents.
Requirements for control of pollution from combined sewer overflows
are rapidly becoming more stringent. Control of pollution caused by
urban storm water discharges is on the horizon.

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INTRODUCTION
Identification of combined sewer overflows as a substantial pollution
(2)
source having National significance was established in 1964 . The
published report indicated that it would cost $20 - $30 billion to
correct the problem, this estimate being based on reconstruction of
the combined sewers so as to provide separate systems for sanitary
sewage and storm waters, accepted practice at that time. The report also
recognized that storm water is a significant source of pollution and
that separation may not be an adequate solution. Exploration of
alternative control measures was, therefore, recommended.
(1)
The Congress, in 1965, authorized a program to develop and demonstrate
"	new or improved methods of controlling the discharge of untreated
sewage or inadequately treated sewage or other wastes from sewers which
carry storm water or storm water and sewage or other wastes." The
research, development and demonstration program of the Environmental
Protection Agency considers "urban runoff" pollution in three source
categories; combined sewer overflows, storm water discharges and non-
sewered urban runoff.
An updated estimate of remedial costs pertaining to combined sewer over-
(3)
flows compiled in 196 7 indicated that a National separation program
would cost $48 billion. Use of alternative measures, based on overflow
storage, was estimated to have the potential to reduce remedial costs
to $]5 billion. It should be noted that the estimates contained in both of the
studies excluded costs associated with abatement of pollution stemming
from storm water discharges and non-sewered urban runoff.
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RESEARCH, DEVELOPMENT AND DEMONSTRATION PROGRAM
Early assessment of the problem within the research, development and
demonstration program indicated that the combined sewer overflow
pollution problem is in reality a reflection of the inefficiencies
(5)(30)
inherent in our collection, transport and treatment systems.
Primary thrust of research, development and demonstration has been to
identify system weaknesses and to develop and demonstrate the technology
and hardware which can be utilized to improve operating efficiency and
capabilities of sewer systems. This can be done only by considering
the problem in the context of the entire system and by applying systems
analysis techniques to define the scope of individual system problems,
as a design tool for remedial action and facilities as well as to assist
in the evaluation of installed facilities.
Recognize that the development of new and improved methods and
the application of demonstrated technology must encompass at least
two principal areas. The first of these, the total system approach,
has already been mentioned. The second involves the sub-systems.
Utilization of the total system approach to problem solving requires
the availability of suitable subsystem or unit processes which can
be wedded to form an entire operable system. Many different alternatives
can be envisioned as potential solutions to combined sewer overflow problems.
Most, however, are not applicable to all of the varied weaknesses within
the entire system, therefore, the means to perform the wedding alluded
to above must be developed. This we have attempted to do by means of
mathematical simulation modelling. A storm water management model
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has been developed for the purpose of simulating the reaction of
urban drainage systems during periods of rainfall. Since the model
includes dry weather flow in the simulation of urban runoff, omission
of a rainfall event(s) results in a simulation of system operation during
dry weather periods. To evaluate overflow conditions, storm events
selected for design purposes by the analyst or designer are programmed
to the computer, along with detailed information concerning the physical
characteristics of the system and other pertinent data. The model then
produces hydrographs and pollutographs at selected points within the
system for each time step. The reaction of the system to modifications
such as installation of holding tanks, flow regulators, treatment
facilities or other changes can be simulated. Costs of remedial
measures can be included. This affords the designer the capability to
select locations, capacity and needed efficiency of remedial facilities
based on predicted system performance. The current generation of the
model is single basin oriented, therefore, it must be run separately for
each outfall.
The model also offers the capability of predicting the affect that system
modifications will have on the receiving waters. Thus, the designer
can fully apply his imagination, ingenuity and engineering knowledge
to plan modifications and extensions to the system which offer the
best pollution control capabilities at least cost. The four-volume
(41)
Storm Water Management Model report which contains a detailed
description of the model, its general capabilities and a user's manual
has been printed.
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Application of total systems techniques to development of solutions
to combined sewer overflow and storm water pollution problems requires
knowledge of unit processes, methods and equipment which can be utilized
to make modification feasible. The bulk of the research, development
and demonstration effort is directed toward improving the state of the
art so as to increase the arsenal of weapons that can be brought to
bear on the problem.
Reporting on advances in technology in this complex technical area
places the reporter in a minor dilemma because there is so much ground
to cover. An important milestone has been reached in that we feel
that sufficient advances have been made to permit the development
and implementation of full-scale remedial programs.
(6)
Pertinent areas for research and development were identified during
the early stages of the research, development and demonstration program
and were utilized to stimulate activity toward development of alternative
control and treatment methods in a wide range of technical areas.
Alternative methods have been pictured as falling into one or more of
three principal categories (1) control (2) treatment and (3) combinations
of control and treatment. These categories are further viewed as sub-
systems or building blocks which are essential to the development of an
efficient collection, transport and treatment system It must be emphasized
that each outfall and each system must be evaluated individually in order
to select and apply the control/treatment facilities on a cost-effecitve basis.
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A fourth category, which includes those areas not specifically a
part of the above categories, but important to each, has been labeled
"miscellaneous". A better term might be "support areas". Development
of the Storm Water Management Model, work on improved flow measuring
methods, special engineering studies, literature abstracting, improved
materials and construction practices and other general technical efforts
supporting and contributing input to efforts in the first three referenced
categories are included.
A brief look at these basic areas will serve to provide a status
report on technology advances.
Control
Storage is the most common method applied for control of combined
(31)	(15)
sewer overflows. Great Britain,	Germany	and other
European countries, as well as the United States and Canada
have utilized tank storage as a basic control method for
many years. However, relatively few such tanks were installed in the
United States prior to the existence of the current demonstration
program. Columbus, Ohio, installed what are believed to be the
first tanks in this country in 1932. Wayne County, Michigan,
is currently devoting considerable effort in this direction.
Inclusion of storage as a part of the research, development and
demonstration effort considers the capabilities of storage as a
control means in the very broadest context—that is, all modes
of storage are considered and are in the process of evaluation.
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Types of storage facilities currently undergoing demonstration
include:
*	Concrete storage tanks
*	Earthen (lined and unlined) retention basins
*	Deep tunnels and mined caverns
*	Utilization of available sewer system storage capacity
*	Vertical, mined "silos"
Point of application of a storage facility is also a factor
of importance to total system performance. Placement of a
facility at the overflow point is an obvious potential selection.
Such a choice must consider that of all potential locations in
the system, the outfall site will require the largest storage
capacity for effective control. It is also the location that,
in most cases, will present the most difficulty in land avail-
ability and cost.
Other sites, function and types of storage should not be ignored.
Placement of control structures at sites upstream of the outfall,
in various portions of the drainage area should be explored. Off-
system storage utilizing parks, golf courses, parking lots, play
grounds, rooftops and similar areas can be employed. Location
at key points in the system other than the outfall has the
potential for making optimum use of sites within the watershed,
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with some potential for cost reduction. This is especially true
if dual use of a site is feasible. Recreation facilities,
parking areas, ornamental ponds and other secondary uses can be
incorporated during the planning and design process. Imagination
and ingenuity are very important to selection of alternatives
and realization of the full potential of sites available.
By utilizing upstream sites it may be possible to use existing
sewer capacity to better advantage and to improve transport
efficiency.
Each community and each overflow site presents unique site character-
istics which may control design. We have found storage costs on
demonstration projects to range from $77,000 to $3,170,000 per million
gallons capacity or, to put it another way, $151 to $42,000 per acre
served. The need for careful site selection and design is obvious.
Examples of the application of storage taken from demonstration
projects will illustrate some of the factors discussed above.
Figure 1 shows an asphalt lined retention basin constructed in
(32)
Chippewa Falls, Wisconsin.	The basin receives combined sewage
by-passed at a major pumping station during storm periods.
Captured flow is returned to the system for transport to the
City's activated sludge wastewater treatment plant following
cessation of the storm. The facility has functioned very
effectively since installation during 1969 and 19 70, eliminating
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59 discharges to the river from 62 overflows from storm events which
occurred during the evaluation period. The basin serves a tri-
butary combined sewer area of 90 acres and contains 3,487,000
gallons or $2,590 per acre served. Design was based on control
of 1.6 inches of storm runoff.
FIGURE I - Asphalt lined retention basin,
Chippewa Falls, Wisconsin
Figure 2 shows a holding facility in Milwaukee, Wisconsin.
The 3.9 mg concrete tank is designed to control a part of the excess flow
from a 570 acre portion (about one-fourth) of the combined sewer area in
Milwaukee. Overflow events are anticipated to be reduced by 70 percent.
Overflows that do occur from the tank are disinfected prior to dis-
charge .
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FIGURE 2 - Concrete holding facility under construction
in Milwaukee, Wisconsin
The complexities of controlling overflows nuzst be recognized in
terms of the capabilities and inadequacies of the entire sewer
system. Utilization of storage capabilities of the existing
system, flow regulation and routing, remote flow and overfiow
sensing and telemetering, remote control facilities, off-system
storage and others will SOon be common practice. Figure 3 shows
the central data logging and control center for the system of
regulators and in-system control project in Seattle. A similar
center at Minneapolis is shown in Figure 4. This type of positive
management of sewer systems will become as necessary and sophisticated
a "malar controls for water distribution facilities, where entire
systems are already remotely controlled.

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FIGURE 3 - Display board and control panel, Seattle,
Washington
FIGURE U - Computer-assisted control room, Minneapolis-
St. Paxil, Minn.
10

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Treatment
Development of the capability to treat extremely high flow rates
on an intermittent basis is a primary objective of the research,
development and demonstration program. Factors that must be
considered include instantaneous flow rate, total volume to be
treated, characteristics of the waste stream, and water quality
standards or objectives for the receiving waters—which in turn
determine the quality of effluent required.
Physical, chemical, combinations of physical-chemical and bio-
logical methods have been considered. Specific processes within
these categories which have been investigated are:
Physical
1.	Fine screening
2.	Microstraining
3.	Dissolved-air flotation
4.	High-rate multi-media filtration
5.	Ultrasonic filtration
6.	Cyclonic and vortex separation
7.	Tube settlers
Chemi cal
1.	Polyelectrolyte sedimentation aids
2.	Chemical oxidation
3.	Disinfection—chlorination, ozonization
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Physical-Chemical
1.	Screening + dissolved-air flotation with flotation aids
2.	Screening - chemical flocculation - sedimentation -
high-rate filtration - carbon adsorption
Biological
1.	High rate plastic and rock media filters
2.	Bio-adsorption
3.	Stabilization Ponds
4.	Rotating Biological Contactor
5.	Deep-tank aeration
Treatment methods can be utilized for at individual overflow points
or as auxiliary facilities at the basic treatment works. The
characteristics of the system will dictate the choice(s). Planning
of control and treatment facilities must first evaluate the means
for physically controlling the overflows. The capability of the
basic treatment works to treat the excess flow on a complete or
partial basis should be the second consideration. The means for
treating controlled overflows at overflow points or by modifying
the basic treatment works should be explored if the existing
treatment works cannot adequately treat them. The possibilities
of dual use deserves thorough consideration. A facility selected
for treating overflows or by-passes may capably serve to upgrade
treatment during normal flow periods.
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Based on the methods which have thus far been demonstrated,
the most applicable for treatment at overflow points include
high—rate multi-media filtration and a combination of screening
and dissolved-air flotation. Both have the capability of
producing a high-quality effluent with design flow rates greatly
exceeding those for more conventional waste treatment processes.
Multi-media high-rate filtration has thus far been demonstrated
at pilot scale to produce suspended solids removals ranging from
75 percent at a filtration rate of 24 gpm/sq.ft. to 87 percent
at a filtration rate of 5 gpm/sq.ft. Reduction of Biochemical
Oxygen Demand (BOD) has averaged 35 percent. Cost for this
process is currently estimated to range from $50,000 to $80,000
per mgd capacity.
The capabilities of the screening-dissolved-air flotation process
have been evaluated in a 5 mgd pilot plant in Milwaukee, Wisconsin,
and are being further studied and evaluated in a 24 mgd facility
constructed by the City of San Francisco.
Combinations of Control and Treatment
Each of the ether methods listed can be used effectively under the
proper conditions. Screening or micros training, for example,
can be applied as unit processes within a total treatment facility
design. A storage or other control facility can include fine
screening or microstraining treatment of flow from the facility
when storage capacity is exceeded during a storm. The treated
overflow can then be disinfected with a resulting effluent of
high quali ty.
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The required capacity for treating combined sewer overflows
will exceed the capacity of the basic municipal wastewater
treatment works—with few exceptions. Findings of the research,
development and demonstration activity thus far indicate that
there is little liklihood that a process will be developed which
can directly handle the instantaneous flow rates generated by
storm events. The coupling of control capabilities; such as surge
basins, in-system storage and others; to form an operable system
will be required. Sophisticated approaches to planning and
design will be needed to accomplish this matching of sub-systems
and formulation of a remedial plan for the community—large or
small.
Combinations of control and treatment offer the designer additional
options and flexibility in developing a remedial plan. The types
of storage mentioned earlier, variable locations and operating
modes for storage or other control methods and the wedding of
control facilities with treatment provide the tools for corrective
actions. Examples of a few of the possible combinations which
can be considered include:
*	Capture and retention followed by pump-back to
the sewer system upon cessation of storm-generated
flow
*	Partial retention with short term sedimentation and
disinfection of tank discharge
*	Retention coupled with fine screening and lis infection
of tank discharges
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*	Retention coupled with chemically assisted sedimentation
*	Long-term retention and treatment of the stabilization
pond type, including disinfection
Other combinations are also possible, but the above listing will
serve to illustrate the broad potential and flexibility of storage
as a control measure.
Figure 5 illustrates concrete tank construction. The facility shown
was constructed by the Metropolitan District Commission of Boston to
serve a combined sewer area in Cambridge. The facility is designed
to receive combined sewer overflows and to provide short-term sedi-
mentation and disinfection prior to discharge to the Charles River.
Minimum retention time of 10 minutes is provided at a design flow of
233 mgd. This provides storage of 1.7 million gallons, which can
be effective for small storms.
FIGURE 5 - Concrete tank construction of detention-
chlorination facility, MDC, Boston, Mass.
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Implementation Concepts
The total systems approach is rapidly emerging as the only problem
solving technique which offers the potential for producing storm
and combined sewer remedial programs that will be not only economi-
cally feasible, but will also be effective from a pollution control
standpoint. This entails a detailed examination of the wastewater
collection, transport and treatment system. Quality of overflows
and other discharges must be determined. The collection and
transport facilities cannot logically be considered separately
from the treatment facilities because the net pollution control
capability and operating efficiency requires that the units such
as sewers, retention basins, regulating and pumping stations, flow
and quality sensing devices, rain gages and others function
effectively as a system.
The Detroit, Seattle and Minneapolis-St. Paul in-system control
demonstration have shown that current technology can produce
the type of system necessary. These projects were not
necessarily designed as complete metropolitan systems.
Instead, they were planned to demonstrate the concept and
to evaluate the hardware and system function. This objective
is being accomplished.
Improved techniques were needed for determining the reaction of
a sewer system during storm periods and for predicting changes
in system reaction in the event that control and treatment
facilities are added to the existing system for the purpose
of abating combined sewer overflow and storm water pollution.
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The Storm Water Management Model mentioned earlier has this
capability. The model, or modifications of it, has been
used by several cities to assess their overflow problems
in terms of quality and quantity as a tool in the remedial
measure planning process and as a means for evaluating performance
of installed facilities. It has been applied to areas as large
as 20,000 acres and as small as 180 acres.
(39)
A similar approach has been developed recently in Germany.
Utilizing computerized mathematical modeling called the
Hydrograph Volume Method, emphasis is placed on maintaining
and improving the efficiency of the sewer system through
system analysis and pre-planning system modifications. The
entire drainage system is considered as a functional hydraulic
unit, existing and projected flows are routed through the
system to determine areas where improvements are or will be
needed. Modifications can then be planned based on system
performance and estimated cost. The model as presently developed
does not include any quality modeling, and its capabilities have
not yet been evaluated in the United States.
The next step in model development and use is expected to be
two-fold: (1) simplification as much as possible without
detriment to the output and (2) modification to make it more
functional as a planning (optimization) tool. Eventually,
it is anticipated that a model taylored and programmed for
a specific municipal or metropolitan sewer system will be
part of a centralized, decision-making and control center;
where measured rainfall will be entered into the real-time
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data bank, system reaction predicted and system controls
activated accordingly—on an automated basis.
Manpower Needs
The success of any urban runoff pollution control program adopted
by a community, rests heavily on the human resources provided to
operate and maintain the system. It must be pointed out that
new manpower capabilities will be required. New, automated
facilities will require specially trained personnel, such as instru-
ment technicians, computer operators, and maintenance staff familiar
with a higher level of equipment sophistication than generally
employed today. Such improvements in staffing will be needed to
augment but not to replace the typical labor force currently
employed in this area.
Recognition of the changing needs in staffing and the improved
training programs required to maintain and upgrade competency
is an issue to bear in mind in formulating local programs.
The needs in this area will be substantial in terms of both
numbers and capability. Recognition must be given to the
personnel needs early in the planning and throughout complete
development and implementation of the remedial program. The
high level of capital investment in facilities must be protected
and the system must operate at high efficiency levels.
Storm Water Discharges
Urban storm water has been found to be a significant source
of pollution. Long believed to be inconsequential (a reason
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used for separating sewers) we now know that the assumption
that storm water is "clean" is erroneous. Data show that
solids, both organic and inorganic; COD; BOD; bacteria; and
nutrient concentrations are high enough to cause serious de-
gradation of receiving waters. One only has to observe the
materials on our streets to detect the reason. Illicit connections
of sanitary and industrial sewers to storm drainage systems also
play an important role in this area. Studies of storm water quality
(34)	(35)	(25)
in Washington, D.C. , Durham, N.C. , Cincinnati, Ohio ,
(36)	(27)(40)
Bucyrus, Ohio , and Chicago, 111.	have provided the
bulk of the information on this subject in the United States.
(33)
Studies in Sweden have indicated that increases in traffic
result in increased storm water contamination.
Research, development and demonstration efforts in the area of
storm-generated wastewater discharges have thus far been concen-
trated primarily on combined sewer overflows because of the dis-
charge of raw sewage that occurs. Data on storm water quality and
results obtained from projects dealing with combined sewer overflows
indicate that some of the control and treatment methods for combined
sewer overflows can be utilized to abate storm water pollution as
well. More work on this problem will be necessary in the near
future.
Non-Sewered Runoff
Research, development and demonstration efforts related to non-
sewered runoff are in the embryo stage. Airport runoff, road
and street de-icing practices, urban erosion control and other
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technical areas will be explored by the storm and combined sewer
research, development and demonstration program as resources
permit.
Current Status
A question that should be asked and that must be answered is:
what impact has the research, development and demonstration effort
had on the pollution abatement programs and what is portended for
the future?
Current impact can, perhaps, be identified by official actions taken.
Recently published regulations pertaining to basin planning (for
water pollution control, for example, require that "....storm
water and mixed storm water and sewage shall be identified and
reported separately in terms of frequency-volume relationships".
This requirement, plus the requirement for quality measurements
for all waste discharges contained in the same regulations,
place a large responsibility on basin planning agencies for
identification of both combined sewer overflow and storm water
discharge pollution problems. Such information is, of course,
necessary to the development of abatement plans.
The Federal Guidelines for Design, Operation and Maintenance of
Wastewater Treatment Facilities require that excessive amounts of
infiltration be identified and plans be developed for bringing the
problem under control. The Guidelines also require that sewage
by-passing be eliminated as far as possible and that consideration
be given to "	separation of combined systems, detention facilities
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or other alternative means* of control or treatment and disinfection
of overflows". The intent is clear—control and treat combined sewer
overflows.
Enforcement actions taken under the Federal Water Pollution
Control Act, where combined sewers constitute a pollution
source, have included control of pollution from overflows
as a part of the required abatement action. The Great Lakes
Enforcement Conference, for example, has set 19 77 as the
target date for bringing this problem under control.
State water pollution control agencies are becoming more
aggressive in their requirements for abating combined sewer
overflow pollution. State orders requiring separation or alter-
native corrective action are being issued.
Results of demonstration projects indicate that alternative
methods can do a more effective job than will separation and
(36)
at less cost. A study in Bucyrus, Ohio,	indicated that
if combined sewers were separated, only 50 percent pollution
reduction would be achieved due to the remaining storm water
pollution. An alternate scheme utilizing an aerated lagoon
to treat combined sewer overflows was estimated to provide a
95 percent reduction in pollution at about 60 percent of the
cost of separation.
Implementation of new, innovative approaches must be accepted.
(42)
An example of such a bold approach is the "Kingman Lake Project."
This EPA conceptual engineering study describes the reclamation of
combined sewer overflows for utilization in a water oriented
recreational facility in the heart of the Nation's Capitol.
*emphasis added	^

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A 175 million gallon below-grade storage basin, coupled with a
50 mgd reclamation facility would provide fresh water for two
46-acre swimming and boating lakes.
Cost effectiveness of the project has been indicated to be
1.6 at an estimated total project cost of $45.2 million, with an
estimated annual operating cost of $1,777,000.
Based on available and developing technology and the emphasis
being placed on requirements for remedial action, it appears
that near-future action in abatement of pollution from combined
sewer overflows will be a reality. Prudent analysis of sewer
system deficiencies and planning for system improvement will
take full cognizance of this fact.
Since urban storm water has been identified as a significant
(23-27)(33)(35)
pollution source,	evaluation of the total urban drainage
system should take this into account, with the objective of developing
plans for extensions and improvers to the storm drainage system in
a manner which will permit the addition of future treatment facilities
at least cost. Some urban areas already face rapid deterioration
of lakes and ponds within their boundaries and will need to begin
now to control pollution from storm water discharges.
Summary
In closing, several points should be re-emphasized. First, the combined
sewer overflow problem exists because we in the water pollution control
field have failed to recognize its extent and importance, but even more
significant, we have failed to build and maintain wastewater collection,
transport and treatment systems that are dependable and efficient
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The second point is that urban storm water discharges from both
sewered and non-sewered sources are significant sources of pollution
that should, and eventually must, be controlled.
The third and most important point is that traditional, staid, "off-
the-shelf" engineering approaches must be abandoned in favor of
innovative, imaginative problem analysis and planning directed toward
the total urban drainage and treatment system. The system is only
as good as its weakest point. Current and emerging technology provides
the basic capability to solve the problems. Application of the best
technology available must be adopted as standard practice.
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REFERENCES
(1)	Federal Water Pollution Control Act, as amended by the Federal
Water Pollution Control Act Amendments of 1961 - (PL87-88), the
Water Quality Act of 1965 - (PL89-234), and the Clean Water
Restoration Act of 1966 - (PL89-753).
(2)	U.S. Department of Health, Education and Welfare, Public Health
Service. Pollutional Effects of Storm Water and Overflows
from Combined Sewer Systems, November 1964.
(3)	American Public Works Association - Research Foundation. Problems
of Combined Sewer Facilities and Overflows - 1967. WP 20-11,
Contract Report for the Federal Water Pollution Control Admini-
stration, December 1967.
(4)	Rosenkranz, William A., Developments in Storm and Combined Sewer
Pollution Control. Presented at New England Water Pollution
Control Association Spring Meeting, June 11, 1968.
(5)	Cywin, Allen; Rosenkranz, William A.; and Wright, Darwin; Improving
the Efficiency of Sewerage Systems. Presented at the Public
Works Congress and Equipment Show, American Public Works
Association, Miami Beach, Florida, October 19-24, 1968.
(6)	Federal Water Pollution Control Administration. Pertinent Areas
for Research and Development, Storm and Combined Sewer Pollution
Control, July 1968.
(7)	Federal Water Pollution Control Administration, Division of
Engineering Development. Research, Development and Demonstration
Projects, Vol. 1, January 1969.
(8)	Anderson, James J., Real-Time Computer Control of Urban Runoff,
presented at ASCE Hydraulics Division Conference, August 23, 19 68.
(9)	Peters, Gerald L. and Troemper, A. P., Reduction of Hydraulic Sewer
Loadings by Downspout Removal, Presented at the Annual Meeting
of the Central States Water Pollution Control Association, St.
Paul, Minnesota, June 12, 1968.
(10)	Caster, A. C., Monitoring Storm Water Overflows, Journal Water
Pollution Control Federation, Volume 34, No. 9, September 1965.
(11)	Kruse, E. Gordon and Haise, Howard R., Performance and Operating
rharacteristics of a Fluidic Irrigation Diverter. Northern
Plains Agricultural Research Station, U.S.D.A., Fort Collins,
Colorado.

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(12)	Weller, L. W. , and Nelson, M. K. , Diversion and Treatment of
Extraneous Flows In Sanitary Sewers . Journal Water Pollution
Control Federation, Vol. 37, No. 3, March 1965.
(13)	Institution of Civil Engineers, Symposium on Storm Sewage Overflows.
Advance papers, May 4, 196 7.
(14)	Ministry of Housing and Local Government, Technical Committee on
Storm Overflows and the Disposal of Storm Sewage - Interim Report.
Her Majesty's Stationery Office, 1963.
(15)	Cohrs, Albert. Storm Water Tanks in the Combined Sewerage System
in Berlin. Gus and Wasserfach, Vol. 103, No. 36, September 7
1962.
(16)	Hubbell, George E. Effect of Storage and Skimming on Combined
Sewage Overflows. Presented at the 39th Annual Conference of
the Water Pollution Control Federation. September 25-30, 1966.
(17)	Gregory, John H.; Simpson, R. H.; Bonney, Orris; and Allton
Robert A. Intercepting	Sewers and Storm Stand-Rv	J
Columbus, Ohio. American Society of Civil EngineerrY^^-
actions, Paper No. 1887.
(18)	Devenis, K. P., Charles a Maguire Associates, Boston University
Bridge Storm Water Detention and Chlorination
at New England Water Pollution Control Association, Spring
Meeting, June 11, 1968.
(19>	• Tuiiels Will Store Storm Rnnnff Engineering Mews Record,
November 30, 1967.	'
(20)	Pikarsky, Milton, and Keifer, Clint, Underflow Sewers for nMnaon
Civil Engineering - ASCE , May 1967.—				 8 '
(21)	R°P°rt on Improvements to the Boston Main Bralnage System Camp,
Dresser and McKee, Consulting Engineers, September 1967.
(22)	McPherson, M. B., ASCE Combined Sewer Separation Project Progess
Presented at the ASCE N^j^iTMeeting on Water Resources 	'
Engineering, New York City, October 16-20, 1967.
Burn, R. J. and^Vaughn, R. D., Bacteriological Comparisons	Between
Combined and Separate Sewer pl^harges in Southed..™ ~
Journal Water Pollution Control Federation Vol 38 No	3 '
March 1966.	' * JO> wo>	J>
(23)
(24) Bum, R. J.; Krawczyk, D. p. ; and Harlow r T	.
Physical Comparison_of_Cpinblned	Chemical_and
Journal Water
January 1968.	aeration, Vol. 40, No. 1,

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(25)	Weibel, S. R.; Anderson, R. J.; and Woodward, R. L.; Urban Land
Runoff as a Factor in Stream Pollution, Journal Water Pollution
Control Federation, Vol. 36, No. 7, July 1964.
(26)	Benzie, W. J. and Courchaine, R. J., Discharges from Separate
Storm Sewers and Combined Sewers, Journal Water Pollution
Control Federation, Vol. 38, No. 3, March 1966.
(27)	American Public Works Association - Research Foundation. Water
Pollution Aspects of Urban Runoff, WP 20-15, Contract Report
for the Federal Water Pollution Control Administration,
January 1969.
(28)	Pavia, Edgar H. and Powell, Crawford J., Storm Water Disinfection
at New Orleans. Journal Water Pollution Control Federation,
April 1969, pp. 591-606.
(29)	HLttman Associates, Incorporated, The Beneficial Use of Storm
Water, Final Project Report for the Federal Water Pollution
Control Administration, August 1968.
(30)	Cywin, Allen and Rosenkranz, William A., Storm and Combined Sewer
Research and Development, ASCE Annual and Environmental Meeting,
Chicago, Illinois, October 13-17, 1969.
(31)	Ministry of Housing and Local Government, Technical Committee on
Storm Overflows and the Disposal of Storm Sewage - Final Report,
1970, Her Majesty's Stationery Office, London.
(32)	Banister, A. W. , P.E., Storage and Treatment of Combined Sewage as
an Alternate to Separation, Federal Water Pollution Control
Administration, Combined Sewer Overflow Seminar Papers. 11020	
03/70, pp. 19-36.
(33)	Soderlund, Gunnar, Swedish Institute for Surface Chemistry,
Lecture on Pollution from Urban Storm Water Runoff, Fifth
Conference, International Association on Water Pollution
Research, July 1970.
(34)	Weston, R. F. Co., Combined Sewer Overflow Abatement Alternatives,
Washington, D.C., Environmental Protection Agency, 11024 EXF
08/70.
(35)	Bryan, Edward H., Quality of Storm Water Drainage from Urban
Land Areas in North Carolina. Water Resources Research
Institute of the University of North Carolina, June 19 70.
(36)	Burgess and Niple, Limited, Stream Pollution and Abatement
from Combined Sewer Overflows - Bucyrus, Ohio. Final project
report prepared for the Federal Water Quality Administration,
(11024 FKN 11/69).

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(37)
Federal Water Quality Administration. Federal Guidelines Design,
Operation and Maintenance of Wastewater Treatment Facilities,
September 1970.
(38)	Federal Register, Title 18 - Conservation of Power and Water
Resources, Fart 601 - Grants for Water Pollution Control.
Vol. 35, No. 128, July 2, 19 70.
(39)	Ritter, F. G., Dr. and Warg, C. Upgrading City Sewer Installations,
Engineering Digest, April 1971.
(40)	Heaney, James P. and Sullivan, Richard H., Source Control of
Urban Water Pollution. Journal Water Pollution Control
Federation, Vol. 43, No. 4, April 1971.
(41)	Met calf & Eddy, Water Resources Engineers, University of
Florida, Storm Water Management Model, Environmental Protection
Agency, 11024 DOC 7/71 (Four Volumes).
(42)	Roy F. Weston, Inc., Conceptual Engineering Report - Kingman Lake
Project, Environmental Protection Agency, 11023 FIX 8/70.

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* EPA Library Region 4
MUMM
STATE LIBRARY
TENNESSEE STATE LIBRARY & ARCHIVE^
NASHVILLE,' TENNESSEE 37219

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