Box 12, Folder 6, Document 35

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Box 12, Folder 6, Document 35

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May y 1967
The problem of pollution from storm and combined sewers is one
which has only recently begun to receive proper emphasis as a signi-
ficant pollution source. There are in the United States over 1900 iit
communities with combined or partially combined sewerage systems ind
serving some 59 million people. lee

The discharge of polluting wastes from storm drainage systems
and overflows from combined sewers serves as a distinct challenge to
the ingenuity of minicipal officials, consulting engineers, universities
and corporations engaged in research and development, as well as equip-
ment manufacturers. Polluting discharges from combined storm and
sanitary sewers occur during wet-weather periods when the carrying
capacity of the sewers is exceeded due to the large amounts of storm
water entering the sewers. The normal, or dry weather flow is prevented
from overflowing continuously by means of overflow weirs, mechanical
regulators, valves and other devices. They permit overflows to occur
when sewer flows reach a predetermined level.

Separation of the storm water from the sanitary sewage can be
at least a partial answer to the problem since if the systems are
completely separated the most concentrated waste load can be conveyed
to and treated at the waste treatment plant. We have come to recognize
in recent years, however, that surface runoff also contains significant
amounts of pollutants - some cases nearly as much as sewage - so
that separation of sanitary wastes is now believed to be only a partial
solution to the total problem.

Congress had these factors in mind when the current storm and
combined sewer pollution control demonstration grants were authorized.
Section 6 (a) (1) of the Federal Water Pollution Act authorizes "----
grants to any State, municipality, or intermunicipal or interstate
agency for the purpose of assisting in the development of any project
which will demonstrate a new or improved method of controlling the dis-
charge into any waters of untreated or inadequately treated sewage or
other wastes from sewers which carry storm water or both storm water
and sewage or other wastes ----." The Federal Government can provide
up to 75 percent of the estimated reasonable cost of individual research,
development and demonstration projects. The applicant must provide
assurances that local funds are or will be available to pay for the
remainder of the cost. Application for contract support for pertinent
research and development projects will also be considered,

The necessary application forms and more detailed information
concerning the Program can be obtained by writing tor

Office of Research and Development

Federal Water Pollution Control Administration
U.S. Department of the Interior

633 Indiana Avenue, N. W.

Washington, D. C. 2022
By way of assisting those who wish to participate in the task
of controlling or abating pollution from storm and combined sewers
the following outline of technical areas for which applications
are desired is provided:


1. Reduce and regulate stormwater input to sanitary sewers |

a. Diversion of surface runoff to the ground water by

altering and controlling land use to increase infiltration

1. Reduction of impervious areas = increasing open spaces

2. Terracing and otherwise reducing land slopes through

3. Planting grasses, trees and shrubbery

4, Reducing extent and time of exposure of bare earth
during land development and construction

b. Shallow pervious basins for percolation to ground water
or use sprinklers

¢e. Ground water disposal wells (injection & others)

d. Reduction of ground water infiltration to sewers

1. Development of better methods of determining location
and extent of sewer infiltration

2. Development of better sewer joints, lateral connections,

3. Development of better methods of repairing existing
lines, making new installations and closing of abandoned

e. Storage of stormwater runoff
1. Temporary storage of stormwater at building or immediate
area through use of holding tanks, seepage pits, roof-
tops, or backyard storage (detention) facilities. Regu-
lated discharge from storage to the groundwater, a Wit
watercourse, or sewer system il
2, Stormwater collection sumps (neighborhood) with regulated
discharge to sewer system (includes storage facility under
3. "Upstream" storage or other control methods to decrease
runoff effect on lower portions of the system
4, Stormwater storage in urban area surface lakes, ponds,
caverns, for subsequent discharge to watercourse or
sewer systems
5. Storage and operating characteristics necessary for
snowmelt runoff
6. Reuse of stored water for irrigation, street cleaning,
sewer flushing and other purposes
2. Hliminate discharge of sanitary sewage and other wastes
to storm sewers

a. Eliminate illicit connections of sanitary sewers where
separate sewers exist

b. Reduce groundwater infiltration to storm sewers
ce. Separation and collection of concentrated waste materials
on the surface for discharge to sanitary or industrial
waste sewers. (Animal waste, industrial materials and
waste projects, sludges, etc.)
3. Reduce solids in storm runoff
a. Soil erosion control
1. Highway, street, and utility construction methods
and practices changes
2. Use of solids retaining pond, basin, or other type
unit with necessary treatment
3. Grass seeding and other type plant coverage of exposed

b. Improved street cleaning and urban "housekeeping" methods
to prevent solids from reaching the sewers

4. Pre-treatment of water entering storm sewers
a. Disinfection only Ki

b. Primary clarification with modifications (with and
without chlorination or other type disinfectants)

c. Lagoons, ponds, tanks with solids holding capacity
for given period .

d. Filtration
e. Treatment for nutrient removals
f. Treatment or storage in catch basins
g. Other treatment methods and processes or combinations
of the above including chemical treatment

1. Improvements in gravity sewer system
» (=

Catch basin improvements including operation and
maintenance practices

Sewer planning and controls to regulate time of flow
during heavy stormwater periods, including sewer
flood flow routing techniques, travel time, etc.

Improved sewer shapes and materials to improve flow
conditions, (lower: "n") better sewer connections and
manhole flow channels

Increase trunk and interceptor design capacity

Improved system design methods utilizing best hydro-
logical practices

2. Special conveyance systems






Limited separation of combined sewers with express
sewer construction for sanitary waste

Partial separation

1. Separate drains for streets, yards, parking lots,
new buildings, etc.

2. Phased separation of sewer systems in all new areas
to be sewered and redeveloped. While this method
could have significant long-range beneficial effects,
demonstration grants for separation of sewers are not

3- Preventing stormwater flows in separate systems from
being discharged to combined sewers

Separation of sanitary sewage and use of separate sewer

inside larger sewers where available to convey sewage
to treatment plant

Use of vacumm conveyance systems.for-sanitary sewage .
& solid wastes


3- Reduce peak flows





Diversion of excess flow from combined sewer to external
facilities for storage and regulated feed back to system
for treatment

In-line treatment to improve flow conditions

In-line detention through use of enlarged segment of

In-system detention of waste and stormwater through
telemetering or other type signaling systems with
remote control on flow.

Reduction in water use through improvements in plumbing
hk. Reduce infiltration and exfiltration



Development of improved methods of locating sewer
leaks; checking out new sewers, laterals and house

Development of new and better methods and materials
for making sewer repairs, closing abandoned openings
and construction in general

Development of methods of sealing sewers in place,
internally and externally, to reduce infiltration.

Improved means of implementing control of illicit
"clearwater" connections to sewers

5. Systems analysis and control methods



In-line (internal) storage with telemetering and
remote or automatic flow control

External storage in tanks, ponds, etc. for feed back
with automatic control system

In-system routing of stormwaters to utilize full storage
capacity of system and subsequent treatment

Others and combinations of (a), (b), (c) (Including
periodic dry weather flushing to move solids deposited
in sewers, and better sewer maintenance in general)


1. Treatment of combined sewer overflow



Treatment at or near point of overflow through use

of conventional type primary treatment units or ponds,
tanks, lagoons with chemical treatment and chlorination.
Other types of treatment facilities or processes.

Use of subterranean holding basins with treatment

Expansion or additions to existing treatment plants to
treat excess flow

Nutrient removal

Treatment with return of concentrate to interceptor for
further treatment at sewage treatment plant
2. Treatment of stormwater runoff

a. Small drainage area plants vs. central plant utilizing |
new or improved methods of treatment idl

b. Utilization of upstream storage to cut peaks and i
control plant input

ec. Pre-treatment and direct ground water replacement
d. Irrigation by spreading, spray or other methods

e. Treatment and use as supplement to raw water supply
f. In-line treatment

g. Others


1. Determination of economic feasibility study of separation
vs. combined sewer system and local vs. central treatment
facilities for overflow and stormwater.

2. Development and demonstration of new or improved accurate
instruments for flow measurement and water quality monitoring.

3. Development and demonstration of improved techniques of hydro=
logic analyses, to determine reasonable accurate rainfall -
runoff relationships. Compilation of sources of existing
data and development of improved statistical methods,

4, Management techniques geared to optimize control and/or
treatment through utilization of new methods,

5. Development of improved construction materials and methods

6. Development of performance criteria needed in relationship
to stream water quality standards

It should be noted that the above outline is not considered to be
all-inclusive, since there may be numerous completely original ideas
which could be added -- some of which may be more significant than any
of those listed. Submission of such ideas to the Federal Water Pollution
Control Administration is strongly encouraged.

Some of the technical areas outlined are currently under evaluation
by means of either grant or contract projects, for example: Most of the
more conventional storage techniques including the use of tanks with
pump~back to the interceptor, surface storage ponds, treatment lagoons
are underway. More unique applications of storage principals such as
localized "upstream" storage to prevent overloading of "downstream"
sewers need further development. The use of chlorine to disinfect
storm and combined sewer discharges: is included in several projects,
therefore new disinfection techniques suitable for application to
high volume -- short duration flows need exploration. Similar
examples can be found in any of the major technical areas listed.

The brief descriptions of existing demonstration projects will
serve as additional examples of work being done. Any further duplication
of these control methods will be minimized as much as possible to permit
activation of projects designed to explore technical areas not now being
evaluated. Some duplication will be in order so as to provide evaluation
of function under a suitable variety of hydrological conditions.


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