FEDERAL GUIDELINES
DESIGN OF WASTEWATER
TREATMENT FACILITIES *•
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REPRINTED
FEBRUARY 1976
U.S. ENVmOISMElNTAL PROTECTION AGENCY
Office of Water Program Operations
Washington, D.C. 20460
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NOTE
These design guidelines are identical to those
portions of the Federal Guidelines: Design,
Operation and Maintenance, published by the
Federal Water Quality Administration in Septem-
ber 1970 pertaining to design. A supplement
entitled Federal Guidelines: Operation and
Maintenance, replaces the O&M portion of the
previous guidelines.
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FEDERAL GUIDELINES
DESIGN OF WASTEWATER
TREATMENT FACILITIES
REPRINTED
FEBRUARY 1976
U.S. EPA Headquarters Ubrary
l code 3201
uya
Washington DC 20460
NW
U.S. ENVIRONMEINTAL PROTECTION AGENCY
Office of Water Program Operations
Washington, D.C. 20460
U.S EPA Headquarters Library
,onnn Mail code 3404T
i^UU Pennsylvania Avenue N
Washington, DC 20460
202-566-0556
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FOREWORD
Effective design and operation of municipal waste water treatment
facilities is an essential element in the preservation and
enhancement of our Nation's waters. The tremendous investment of
Federal, State, and local funds in these facilities must be protected,
We must incorporate past experience and new technology in this
generation of facilities to ensure that optimum benefits are derived
from expenditures in water pollution control. The development of
these Guidelines represents a significant step toward the achievement
of these goals.
Many have contributed to the development of these Guidelines. I
particularly wish to thank the Ad Hoc Advisory Group, composed of
representatives of the American Society of Civil Engineers, the
Association of Metropolitan Sewerage Agencies, the Association of
State and Interstate Water Pollution Control Administrators, the
Great Lakes-Upper Mississippi Board of Sanitary Engineers, the
U. S. Council of Consulting Engineers, the Water and Wastewater
Equipment Manufacturers' Association, and the Water Pollution Control
Federation, for their advice and counsel in reviewing the Guidelines
and in developing the general procedures.
"David D. Dominick, Commissioner
Federal Water Quality Administration
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TABLE OF CONTENTS
FOREWORD 11
INTRODUCTION 1
GUIDELINES FOR DESIGN 5
A. Preliminary Project Planning and Engineering Report 7
environmental compatibility
regionalization
project feasibility
complete and operable treatment works
ultimate disposal of sludge and solids
treatment plant reliability
excessive infiltration
elimination of by-passing
industrial wastes
staffing and budget for a facility
design period
combined sewerage systems
B. Preparation of Plans and Specifications 18
design sunmary
reliability
discharges to shellfish, potable or recreational waters
elimination of by-passes and overflows
treatment during construction
experimental processes or equipment
flexibility and ease of operation and maintenance
protection of effluent quality
safety features
interceptor sewers
general requirements
GUIDELINES FOR OPERATION AND MAINTENANCE 31
A. Federal and State Inspections 31
B. Personnel 35
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C. Records, Reports, and Laboratory Control
D. Process Control
APPENDIX
Suggested Guide for an Operation and Maintenance Manual
37
39
42
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INTRODUCTION
Over the past year the Federal Water Quality Administration has
carefully analyzed and evaluated its grant program for the
construction of waste treatment facilities. Fast experience
indicated that some of the projects that have received assistance
have, for a variety of reasons, not always been as successful as
anticipated. Improved design practices and technological advances
are not being adequately incorporated into new plants. Operators
are often poorly trained and paid. Facilities are frequently badly
maintained and achieve far less than their designed efficiency levels.
FWQA has an obligation to ensure that Federal monies are wisely spent.
This Administration must insist on proper design and operation
procedures as it is clear that without them adequate levels of
treatment will not be obtained.
On February 10, 1970, President Nixon announced a 37 point program
to improve the Federal government's environmental protection programs.
In this message he directed the Secretary of the Interior to require
that Federally-assisted treatment facilities meet prescribed design,
operation and maintenance standards. Only July 2, 1970, the
Department of the Interior issued new regulations for the
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construction grants program to implement the President's directive.
Section 601.35 of Title 18 of the Code of Federal Regulations
concerns the area of operation and maintenance of facilities;
Section 601.36 concerns the design of facilities.
Section 601.36 states that "no grant shall be made for any project
unless the Commissioner determines that the proposed treatment works
are designed so as to achieve economy, efficiency, and effectiveness
in the prevention or abatement of pollution or enhancement of the
quality of the water into which such treatment works will discharge
and meet such requirements as the Commissioner may publish from
time to time concerning treatment works design so as to achieve
efficiency, economy and effectiveness in waste treatment."
There are existing manuals, such as the various State and interstate
standards and the ASCE-WPCp manuals, which can be used as references
in the design of water pollution control facilities. Although these
are generally adequate, it is important to emphasize that FWQA is
not necessarily in full agreement with all criteria and concepts
contained therein. Certain design considerations are not
adequately emphasized, and adequate guidance is not given in those
areas where there have been recent technological advances.
To supplement the existing standards, FWQA has developed
Guidelines for Design. These Guidelines are not intended to
cover all aspects of engineering design. Rather they outline,
generally in broad terms, specific FWQA interests and policies that
are not adequately reflected in the presently existing manuals.
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In addition to these Guidelines, FWQA will be issuing Technical
Bulletins. Each Bulletin will cover a certain topic in detail.
These Bulletins are intended to amplify specific areas contained
in the Guidelines, define and analyze certain deficiencies in
design, and evaluate new advances in technology and provide guidance
for incorporating these in new facilities. The Bulletins will
combine the results of our field experience and our research and
development program, along with the efforts of outside experts
and consultants.
Together with the applicable portions of presently existing
manuals and the attached Guidelines, the Technical Bulletins
will cumnulatively constitute the FWQA design requirements referred
to in Section 601.36.
Section 601.35 states that "no grant shall be made for any project
unless the State water pollution control agency assures the
Commissioner that the State will inspect the treatment works not
less frequently than annually for the 3 years after such treatment
works are constructed and periodically thereafter to determine
whether such treatment works are operated and maintained in an
efficient, economic, and effective manner and unless the applicant
assures the Commissioner that the treatment works will be maintained
and operated in accordance with such requirements as the Commissioner
may publish from time to time concerning methods, techniques, and
practices for economic, efficient, and effective operation and mainte-
nance of treatment works."
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The number and frequency of the inspections called for by the
regulation are the absolute minimum necessary to ensure proper
maintenance and operation of a facility. FWQA will be working
closely with the States to ensure that inspections are adequate
in scope as well as in frequency.
FWQA has developed Guidelines for Operation and Maintenance
which provide the general basic requirements in the areas of
inspections, operation and maintenance for Federally-assisted
projects. FWQA will be issuing Technical Bulletins which, as in
the case of the Technical Bulletins for Design, will provide
amplifications in certain specific areas.
The Guidelines and future FWQA Technical Bulletins for design and
operation and maintenance should be maintained in appropriate files
by State water pollution control agencies, consulting engineers, and
all other interested parties. In the future, projects for which
Federal grant assistance is requested are expected to comply with
these Guidelines and Technical Bulletins. While in exceptional
cases deviations may be accepted, any deviations must be
justified on a case-by-case basis and approved by FWQA prior
to their initiation.
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GUIDELINES FOR DESIGN
These Guidelines are intended to supplement existing references
such as the Recommended Standards for Sewage Works: Great Lakes-
Upper Mississippi River Board of State Sanitary Engineers (the
Ten State Standards), the ASCE Manuals Number 36 and 37 (WPCF
Manuals 8 and 9), and applicable State standards and guidelines.
All water pollution control projects which are submitted for FWQA
construction grants will be required to conform to these Guidelines
and future Technical Bulletins, as well as to applicable State
requirements. It is recognized that certain modifications or
exceptions may be necessary when justified in unusual situations.
In such cases under appropriate conditions, deviations from existing
standards or Guidelines may be allowed. However, written approval
of any deviations from the Guidelines, Technical Bulletins, or
applicable State standards must be obtained from the FWQA Regional
Office and the State agency as early as possible prior to the
completion of detailed plans and specifications.
These Guidelines are presented in two parts. Part A deals with
general concepts which must be considered very early in the
planning and preparation of an engineering report for waste
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treatment facilities. Part B makes reference to more specific
subjects which must be considered in the preparation of final
construction plans and specifications.
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A. PRELIMINARY PROJECT PLANNING AND ENGINEERING REPORT
Certain basic principles should be considered early in the
planning process for water pollution control facilities .
Conformance with these principles is essential to ensure the
eventual development of properly designed facilities which will
meet all State and FWQA requirements.
The engineering report accompanying the application for Federal
aid should clearly indicate compliance with the following
principles. Any questions regarding the applicability of these
items to the proposed project or requests for deviations should
be resolved by consultation with the State water pollution
control agency and the FWQA Regional Office before completion
of the engineering report and submission of an application for
Federal aid.
I. Environmental Compatibility
All Federally-assisted projects must conform to the intent
of the National Environmental Policy Act of 1969 and
Executive Order 11514, Protection and Enhancement of
Environmental Quality.
a. Planning for the proposed project must take into
account all aspects of environmental quality protection.
Efforts shall be taken to preserve natural beauty,
wildlife, recreational areas, historic sites, and
private property.
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b. The project must be designed and constructed so as to
have the least possible impact on the environment.
c. Attention roust be given to the general aesthetic
appearance of the facility and to the prevention of any
possible odor problems.
d. Planning shall be coordinated with local planning and
citizen groups to resolve potential site problems.
e. Plant locations on flood plains should be avoided
whenever practicable. When such locations are
unavoidable, adequate protection from flooding must
be provided.
II. Regionalizatipn
a. Due consideration must be given to the advantages of
regional and basin sewerage facility planning. Whenever
feasible, municipalities should join together in
cooperative regional treatment systems, composed of one
or more treatment plants depending on water quality
requirements and economic, operational, and other
appropriate considerations.
b. Where regional waste water management plans have been
developed and approved by an appropriate agency, the
project should conform to such plans.
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c. If a regional plan has not been developed, an analysis
shall be made to determine the feasibility of having
the municipality join in a regional system in lieu of
constructing their own independent or additional treat-
ment facilities .
III. Project Feasibility
a. After consideration of all alternatives, the design of
the proposed project shall be made on the basis of
economic feasibility, water quality objectives,
environmental compatibility, and other applicable
considerations. That certain portions of the system are
eligible for Federal assistance and others are not
should not determine the final nature of the project.
b. In order to avoid tying up Federal grant funds for
unreasonably long periods of time, the project for
which Federal aid is requested, including other
facilities required to make it operable, should be of
such a scope that it can be completed and in operation
within three years of the date of the Federal grant
offer. For unusually large and complex projects, a
longer period of time may be allowed. Additional
phases of the project may be submitted for consideration
for Federal aid in future years when the anticipated
construction period will meet these requirements.
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IV. Complete and Operable Treatment Works
a. Any proposed project must be designed and reviewed in
light of the entire waste treatment system. No project
will be approved unless it is shown that the capacity
and treatment provided by the waste treatment system
serving the proposed project will meet all FWQA,
State, and interstate requirements, including approved
water quality standards, and protect the designated uses
of the receiving waters.
b. If construction of other facilities is required to make
the proposed project operable and acceptable, then a
commitment must be made that the required construction
will be concurrent with that of the proposed facility.
V. Receiving Waters and Degree of Treatment
a. Proposed treatment must be in accordance with State
requirements, as well as with Federal and State water
quality standards, Federal Enforcement Conference
requirements, comprehensive river basin reports and
plans, FWQA Regulations, and the designated uses of
the receiving waters.
b. Characteristics of receiving waters must be considered
to ensure that water quality standards will be met by
the proposed treatment. Applicable data shall be
included in the engineering report.
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c. The engineering report shall specifically indicate the
anticipated removal efficiency of BOD, suspended solids,
and other appropriate parameters, and the total pounds
of BOD, suspended solids, and other significant
constituents to be discharged per day.
d. There should be no discharge of effluents to swamps,
stagnant waters, small lakes, or intermittent streams
if feasible alternates are available.
e. Outfalls shall be extended and designed as necessary to
insure adequate mixing and dispersal of the effluent.
f. Disposal of a treated effluent to other than surface
waters requires prior approval from the State and FWQA.
VI. Ultimate Disposal of Sludge and Solids
a. Provision for ultimate disposal of sludge must be
clearly indicated and must be in accordance with
interstate, State, and FWQA requirements. It is not
sufficient merely to indicate such processes as drying
beds, vacuum filters, or incinerators, without also
describing the method to be used for final disposal of
the sludge cake or sludge residues.
b. The method of final disposal must not result in any
significant degradation of surface or ground water, air,
or land resources. If there is a choice, the method
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chosen must be that having the least impact on the
environment.
c. No sludge residues, grit, ash, or other solids may be
discharged into the receiving waters or plant effluent.
The disposal of any sludge to ocean waters is not
recommended.
d. Disposal of raw sludge to fresh or marine waters or by
spreading and tilling on land will not be approved.
e. Sludge elutriation is not considered desirable and will
not be approved without adequate safeguards.
VII. Treatment Plant Reliability
a. All water pollution control facilities should be planned
and designed so as to provide for maximum reliability
at all times.
b. The facility should be capable of operating
satisfactorily during power failures, flooding, peak loads,
equipment failure, and maintenance shutdowns. A
minimum of primary treatment should be provided at all
times. Disinfection and higher degrees of treatment
may be required where necessitated by the uses of the
receiving waters.
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c. Such reliability can be obtained through the use of
various design techniques which will result' in a
facility which is virtually "fail-safe." (See Part B,
Section 13, page 20 .)
VIII. Excessive Infiltration
a. Excessive infiltration is an indication of deficiencies
in the sewerage system. This situation is often
categorized by high per capita flows to the treatment
facility.
b. Construction of treatment facilities with extra capacity
to handle these excessive flows may not be the best
solution to the problem, since this may result in
unnecessary capital and operating costs and in
inefficient treatment.
c. An analysis of the sewerage system must be made to
determine the causes for such excessive infiltration
where it occurs and, where feasible, an acceptable
remedial plan of action should be prepared to correct
the situation.
d. Solutions, such as separation of illegal storm water
connections, repair or replacement of defective sewers,
and enforcement of sewer ordinances, must be discussed
in the report together with an adequate cost analysis
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before any recommendation is made to construct an
oversized treatment facility or to allow by-passing of
excess flows.
IX. Elimination of By-passing
a. In systems handling only dry-weather flows, the incorpo-
ration in the design of mechanisms for by-passing
treatment plants or pumping stations must be avoided
if at all possible. Any exceptions must have prior
approval of the State and FWQA.
b. Where incorporation of by-passing facilities is
necessary, consideration must be given to separation of
combined systems, detention facilities, or other
alternative means of control or treatment, and
disinfection of overflows.
c. Adequate safeguards to prevent misuse of by-pass
facilities must be provided.
d. Extended by-passing during construction will not be
permitted. (See Part B, Section IV, page 21.)
X. Industrial Wastes
a. The engineering report should clearly define the
characteristics of the wastes from major or
significant industries and their effects upon the
waste treatment process.
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b. Where necessary, pilot plant studies should be made to
determine the final design criteria for the treatment
facility.
c. It is necessary that adequate industrial waste ordinances
or other controls be adopted by the municipalities in
order to protect and maintain the treatment facilities.
These shall provide for the following:
1. Pretreatment of any wastes which would
otherwise be detrimental to the collection
system, treatment facilities, or processes.
2. An equitable system of cost recovery in
accordance with Federal Regulations,
18 CFR 601.34c.
XI. Staffing and Budget for a Facility
A thorough analysis must be made of the operation and
maintenance requirements of the proposed facility,
including required laboratory testing. Specific
recommendations shall be given in the engineering report
for staffing, including operator qualifications, and
annual budget needs of the proposed treatment facility.
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XII. Design Period
A careful review of the growth potential of the area to be
served by a waste water facility should be made to
adequately provide for the increased waste loadings that
are expected to develop. Both domestic and industrial
loadings should be discussed in the report. It is not
considered feasible for FWQA to establish a standard
minimum design period because the growth characteristics
of a particular area may be such that a minimum design
period would cause uneconomical design and inefficient
operating conditions after the project is constructed
The rationale for design will be as follows:
a. When rapid growth is anticipated, the design period
should be long enough for orderly spacing of construction
contracts and the design should permit sufficient
flexibility to prevent inefficient operation of
individual units. The design layout of a treatment
facility should consider the ultimate development of the
watershed being served and the characteristics of the
receiving waters. Construction may be phased to meet
treatment demands.
b. Where the anticipated growth of an area is estimated to
be relatively slow, the design should be for a reasonable
growth rate with sufficient flexibility of sizing of units
to ensure efficiency of operation.
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c. The plant site must be sufficiently large to permit
expansion of the facility to provide for foreseeable
future needs, such as increased capacity and higher
degrees of treatment.
d. The plant must be designed to facilitate expansion and
possible upgrading of the facility.
XIII. Combined Sewerage Systems
The problem of pollution from combined systems shall be
considered in early project planning. Possible solutions,
both short and long term, shall be outlined in the
engineering report. Consideration shall be given to
detention facilities and disinfection, separation of
combined systems, treatment or control of overflows or
o ther solutions.
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B. PREPARATION OF PLANS AND SPECIFICATIONS
The items outlined under Part A, Preliminary Prolect Planning
and Engineering Report. must also be considered when proceeding
with final design details. The following guidelines more
specifically indicate how these considerations and others are to
be applied in the preparation of final contract plans and
specifications.
I. Design Summary
A Design Summary, including but not limited to the following
items, will be required with submission of final plans and
specifications unless acceptable data are already included
in the engineering report.
a. A flow diagram indicating the project's major features
and the nature of flow and recirculation through the
various processes.
b. A hydraulic profile of flow through the treatment plant.
This profile should clearly indicate that the peak flow
will pass through the treatment facilities without
back-up, flooding, or submerging weirs. The hydraulic
gradient should permit discharge into the receiving
waters during periods of flood stage.
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c. Identification of receiving waters and location of
point of effluent discharge. This should be shown on
a map that would allow transferral to standard U.S.G.S,
maps. In addition, detailed information should be
provided on the water quality, water uses, and
hydraulics of the receiving waters at and near the
point of discharge.
d. The initial population, population equivalent, and
flow to the facility.
e. Identification, including expected strength and
toxicity, of major or significant industrial waste
contributions.
f. The design year, design population, and flow.
g. Design efficiency, such as removal of BOD, suspended
solids, and other appropriate parameters and the total
pounds of BOD, suspended solids, and other significant
constituents discharged per day.
h. Physical characteristics of treatment units, including
size, surface loadings, and detention times.
i. Identification and justification of any deviations
from applicable standards or FWQA Guidelines and
Technical Bulletins.
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j. Method of ultimate sludge disposal.
k. Identification and explanation of any unusual design
features.
II. Reliability
The treatment facility should be capable of satisfactory
operation during emergencies, maintenance shutdowns, and
power failures. (See Part A, Section VU, page 13.) This
type of reliability shall be achieved by consideration and
appropriate inclusion of such design factors as:
a. Duplicate sources of electric power.
b. Standby power for essential plant elements.
c. Multiple units and equipment.
d. Holding tanks or basins to provide for emergency
storage of overflow and adequate pump-back facilities.
e. Flexibility of piping and pumping facilities to permit
rerouting of flows under emergency conditions.
f. Provision for emergency storage or disposal of sludge.
Ill. Discharges to Shellfish. Potable1 or Recreational Waters
Discharges in close proximity to shellfishing beds,
public water supply intakes, or contact recreation areas
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should be avoided. Where such discharges are unavoidable,
special precautions must be taken. In addition to the
items listed above, the following are-recommended and may
be required:
a. Dual chlorination units.
b. Automatic facilities to regulate and record chlorine
residuals.
c. Automatic alarm systems to give warning of high water,
power failure, or equipment malfunction.
d. Sand filters or polishing ponds following secondary
treatment.
IV. Elimination of By-passes and Overflows
a. Plant and up-stream by-passes should not be permitted.
(See Part A, Section DC, page 14.)
b. Exceptions, even for combined systems, shall not be
considered until every effort has been made to minimize
the discharge of untreated waste water to waters by
utilizing detention facilities or other alternative
means of control or treatment, disinfection of
overflows, separation of combined systems, and correction
of excessive infiltration.
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V. Treatment During Construction
a. If at all possible, by-passing of raw sewage during
the construction of additions to existing treatment
facilities shall not be allowed.
b. During alterations to existing plants, the same degree
of treatment provided by the existing plant should be
continued. If this is not feasible, a minimum of
primary treatment and disinfection should be provided
at all times.
c. The consulting engineer must either establish a
construction schedule which will minimize or prevent
by-passing or require the contractor to submit such
a schedule before construction commences. The
requirement for continuous treatment must be clearly
stated in the contract plans and specifications.
d. Where no other feasible alternative exists, by-passing
may be permitted providing it is kept to an absolute
minimum and receives prior approval from the State and
FWQA.
e. Measures to be taken for control of erosion at the
construction site must be included in the plans and
specifications or otherwise provided for by the
consulting engineer and/or contractor.
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VI. Experimental Processes or Equipment
a. FWQA encourages the application of new approaches to
treatment plant design and operation. Aid for the
construction and operation of facilities demonstrating
experimental processes or equipment is available under
the FWQA Research, Development and Demonstration Program,
b. Section 8 P. L. 84-660 grant funds may be used for
facilities incorporating new processes or equipment
which have had limited prior use, providing the project
is reasonable in scope and preliminary results are
favorable.
c. In such cases, the contract specifications must
include details on performance criteria that are
acceptable to the State and FWQA. In some cases,
adequate performance guarantees may be required.
d. Prior approval of the State and FWQA must be
obtained before preparation of contract plans and
specifications for such projects.
VII. Flexibility and Ease of Operation and Maintenance
a. The design of process piping, equipment arrangement,
and unit structures in the facility must allow for
efficiency and convenience in operation and maintenance
and provide maximum flexibility of operation. Such
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flexibility should permit the highest possible degree
of treatment to be obtained under varying circumstances,
b. Process controls, such as the return and measurement
of sludge in the activated sludge process, variable
recirculation capacity for trickling filter plants,
and the feeding of raw wastes directly into aeration
tanks, should be provided.
c. All equipment shall be easily accessible so as to
provide ease of maintenance.
d. Adequate facilities shall be provided for taking test
samples at required locations,
e. Multiple units or dual compartments with unit drains
should be provided for all processes, including
disinfection facilities, so that draining, cleaning,
and other maintenance can be provided without omitting
any treatment process. For small plants retention
basins may be substituted for these purposes.
f. All basins and tanks in locations subject to high
ground water levels or flooding should be provided
with back-flow relief valves.
g. The use of equalization tanks to decrease the impact
of peak loads is recomnended.
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h. Color coding shall be provided to Identify each type
of process piping in the treatment plant.
i. An adequately designed and equipped laboratory shall
be provided.
J. Equipmenc with high noise levels, such as compressors
and centrifuges, shall be enclosed in separate rooms,
which should be sufficiently soundproof to protect the
operator and to satisfy neighborhood environmental
requirements.
k. Instrumentation should be used to facilitate operation
and recordkeeplng. Flow measurement and recording
equipment should be provided at the Influent end of
the plant*
1. All materials of construction shall be such as to
withstand local climatic and other environmental
conditions. This is particularly important in coastal
areas.
Vin. Protection of Effluent Quality
a. All aspects of plant design, Including the layout
of tanks and piping, shall allow for routine maintenance
of treatment units without deterioration of the plant
effluent.
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b. The flow from all unit drains must be directed back to
the treatment plant and not discharged into the plant
effluent.
c. Baffles or other means must be provided across the
surface of primary tanks, secondary tanks, and chlorine
contact tanks to prevent the discharge of floating
materials*
d. All final settling tanks must be provided with skimming
devices to collect and remove floating solids.
e. Extended aeration plants must be equipped with sludge
holding tanks for wasting excess sludge so as to prevent
sludge carryover into the effluent. Polishing lagoons
or sand filters are recommended following this type of
facility.
f. No piping may be installed which would allow for the
direct discharge of sludge solids or ashes into the
effluent or receiving waters.
g. Piping should be arranged so that no supernatant, including
drainage from sludge beds, centrate, filtrate, overflows
from thickening units and digesters, etc., is discharged
into the effluent. Supernatant should either be
returned to the treatment process or, preferably, be
given separate treatment and disposal.
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IX. Safety Features
As indicated before, these Guidelines are not Intended to
be all inclusive. The safety features enumerated below are
those which deserve increased emphasis.
a. Chlorine facilities must be provided with proper
ventilation and heating. The fan switch shall be
located outside of the facility. The chlorine storage
area should be separated from the feed area and from
the remaining plant areas.
b. The wet wells and dry wells of pumping stations must
be provided with positive means of ventilation.
c. The treatment plant shall be enclosed as necessary to
protect the public and the facility.
d. Protective railing shall be provided around open tanks
and other areas where it may contribute to safety.
e. Explosion-proof motors, controls, and electrical wiring
and lighting shall be provided in all hazardous areas,
such as the digester control building and enclosed wet
wells.
f. The public water supply must be protected to eliminate
the possibility of contamination by cross connections
with sewage or sludge piping. This should be achieved
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by a positive air break, although an adequate automatic
flow-back prevention device may be acceptable under
certain circumstances. Installation should be on the
main water line where it first enters the treatment
plant or pumping station and prior to any plant piping
connections, including yard hydrants.
g. Flood lights shall be provided for nighttime inspection
and maintenance.
h. Signs shall be provided designating hazardous areas and
nonportable water taps.
X. Interceptor Sewers
a. Particular attention shall be given to ensure that
sewers will be as water tight as possible. Plans and
specifications shall include the following.
1. Infiltration or exfiltration requirements with
maximum allowable limits.
2. Bedding and backfill specifications including cross
section details.
3. Jointing specifications to provide for minimum
infiltration.
4. Requirements for post construction testing to
determine compliance with specified limitations on
infiltration.
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b. Adequate subsurface investigations should be made to
identify underground conditions such as the presence
of rock or unsuitable soils. The.bid proposal should
be based on an evaluation of such investigations.
XI. General Requirements
a. The contract specifications must include all FWQA
administrative requirements. These include such
items as project signs, labor standards, wage rates,
civil rights, and competitive bidding. Required
subjects and documents can be obtained from the
applicable State agency or FWQA Regional Office.
b. Plans and specifications shall be prepared with all
necessary details to permit the contractor to properly
evaluate the cost of the project and to submit a
competitive bid. Details shall be sufficiently clear
and complete to avoid the issuance of unnecessary and
costly change orders.
c. Those portions of the project that are eligible for
Federal aid under P. L. 84-660 must be clearly
identified and contained either in separate contracts
or in separate bid schedules in the contract
documents.
29
* U.S. Government Printing Office: 1976-682-935/286 Regions
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DATE DUE
Omeo, Inc. 38-293
U.S EPA Headquarters Librae.
Marl code 3404T
VOO Pennsylvania Avenue IW<
Washington, DC 20460
202-566-0556
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