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Discussion Paper Number 1
Key Components of Operational, Maintenance and Remediation Programs for
Municipal Sanitary Sewer Collection Systems
 draft - October 22, 1998

Introduction

There are many ways to structure and organize the operational, maintenance and remediation programs for municipal sanitary sewer collection systems. However, all programs should at a minimum, include measures to:

  1. Identify and track municipal sanitary sewer discharges*.
    *Requirements to report SSOs to the NPDES authority are being considered separately.
  2. Stop and mitigate the impact of municipal sanitary sewer overflows that occur as soon as possible;
  3. Ensure the public receives adequate notification of overflow events and impacts;
  4. Provide adequate preventative and routine maintenance, including predictive preventative maintenance approaches with a process to continually review and update maintenance procedures as new problems arise or the status of existing situations change;
  5. Provide adequate maintenance facilities, equipment and spare parts inventory.
  6. Identify the causes of any overflow, implement the appropriate combination of short-term and long-term remediation actions, and modify operational and maintenance measures to prevent recurrence. Examples of remediation measures are targeting operation and maintenance measures, reduction of inflow and rainfall-induced infiltration and improving conveyance capacity by removing system bottlenecks, identification and removal of cross connections, providing relief sewers, increasing sewer size, providing storage and/or optimizing treatment plant operations during peak flow conditions.
  7. Implement and enforce a sewer use ordinance or other legally binding document that:
    1. Prohibits new connections from inflow sources and requires that new sewers and connections to the treatment works be properly designed and constructed.
  1. Ensures proper installation, testing, and inspection of new sewers, including portions of the collection system that are owned by another entity but discharge into the permittee’s sewer system (such as new collector sewers and service laterals); and
  2. Requires that all wastewater introduced into the collection system not contain toxics or other pollutants in amounts or concentrations that endanger public safety and physical integrity of the collection system or treatment works; cause violation of effluent or water quality limitations; or preclude the selection of the most cost-effective alternative for wastewater treatment and sludge use or disposal.
  1. Develop and track performance indicators to characterize:
    1. system performance, including hydraulic performance of the collection system during wet weather conditions; and
    2. key activities used to implement paragraphs (a) through (g).

Selection and implementation of control measures should be based on site-specific considerations including the specific characteristics of the sewer system. Specific measures are to be consistent with industry and State practices and guidelines. Table 1.1 provides a limited summary of references to industry practices and guidelines for the different classes of measures. Table 1.1 is not all inclusive and in general does not address State practices and guidelines.

Numeric Criteria for Operational Requirements

Some available information suggests that national minimum numeric criteria for may not be appropriate at this time for the following reasons:

  1. Several studies have recommended that national numeric preventative maintenance standards for municipal sanitary sewer collection systems are not practical at this time because there is very little correlation of existing preventative maintenance data to system performance** and
    **See "Collection Systems: Methods for Evaluating and Improving Performance", California State University, 1998, and "Stopping SSOs: Beneficial Maintenance Practices" Charlotte-Mechlenberg, SSO National Conference, EPA, 1995.
  2. Preventative maintenance programs need to be tailored to the site specific operational characteristics of a given collection system. Defining national minimum requirements may work against this by driving programs toward the minimum rather than providing flexibility to focus on priority and critical sewers.

Issues

  1. Do the 8 measures listed above provide a comprehensive outline of the measures that should be included in operational, maintenance and remediation programs for municipal sanitary sewer collection systems?
  2. What additional references should be listed under Table 1.1?

Updates

This draft paper will updated periodically to reflect new data and comments. The most recent version of the paper will be posted at the following internet site:
http://www.epa.gov/OW-OWM.cfml/wet.cfm#sso

Comments related to the discussion papers can be sent to:

Kevin Weiss
U.S. EPA (4201)
401 M Street SW
Washington DC 20460
or
e-mail address: Weiss.Kevin@EPA.gov

Table 1.1 - MAJOR INDUSTRY TECHNICAL REFERENCES

Measure

Technical References

Identify and track discharges***

Sewer System Infrastructure Analysis and Rehabilitation Handbook, EPA, 1991

Response and mitigate

Draft - Guidebook for Local Governments: Preparing Sewer Overflow Response Plans, APWA, 1998

Public notice

Combined Sewer Overflows - Guidance for Nine Minimum Controls, EPA, May 1995, EPA 832-B-95-003

Preventative and routine maintenance

Wastewater Collection Systems Management, Manual of Practice No 7, Water Environment Federation, draft revisions 1998.
Operation and Maintenance of Wastewater Collection Systems, a field study training program, Fourth edition, California State University, Sacramento, 1993.
Manual of Practices- Wastewater Collection Systems, NASCO, 1995
Detection, Control and Correction of Hydrogen Sulfide Corrosion in Existing Wastewater Systems, EPA-832-R-92-001, Sept, 1992

Remediation actions

Sewer System Infrastructure Analysis and Rehabilitation Handbook, EPA, 1991
Existing Sewer Evaluation & Rehabilitation, WEF manual of practice FD-6, ASCE Manual and report on engineering practice no. 62, 1994
Recommended Specifications for Sewer Collection System Rehabilitation, 5th ed., National Association of Sewer Service Companies, 1987
Inspector Handbook for Sewer Collection System Maintenance and Rehabilitation, NASCO, 1993
Specification guidelines for Wastewater Collection Systems Maintenance and Rehabilitation, 9th ed., NASCO, 1996
Sewer System Evaluation Rehabilitation and New Construction: A Manual of Practice, APWA, EPA, Dec. 1987, EPA/600/2-77/017d
Handbook for Sewer System Evaluation and Rehabilitation, EPA, 1975
Draft - Monograph: Control of Infiltration/Inflow (I/I) In Private Sewer Service Connections, WEF, 1998
Demonstration of Service Lateral Testing and Rehabilitation Techniques, EPA, 1985
Recommended Specifications for Sewer Collection System Rehabilitation. National Association of Sewer Service Companies. 1985.
Handbook for Sewer System Evaluation and Rehabilitation, EPA, 1975, EPA/430/9-75/021

Sewer use ordinance - Testing of new sewers

Demonstration of Service Lateral Testing and Rehabilitation Techniques., EPA, 1985
Gravity Sanitary Sewer Design and Construction, ASCE manual and report on engineering practice no. 60 and WPCF manual of practice no FD-5, 1982.
Manual for Sewer Inspectors. Consulting Engineers Council of Michigan. 1974.

Performance indicators

Collection Systems: Methods for Evaluating and Improving Performance, California State University, Sacramento, 1998.
Draft - Optimization of Collection System Maintenance Frequencies and System Performance, ASCE, 1998.
Benchmarking Wastewater Operations-Collection, Treatment, and Biosolids Management, WERF, Project 96-CTS-5, 1997

General design issues

Construction Grants 1985, EPA, 1984, EPA/430/9-84/004
Recommended Standards for Sewage Works, Policies for the Review and Approval of Plans and Specifications for Sewage Collection and Treatment, 1990, A report of the wastewater committee of the Great Lakes-Upper Mississippi River Board of State Public Health and Environmental Managers.
Technical Report 16 - Guides for the Design of Wastewater Treatment Works, 1998, New England Interstate Water Pollution Control Commission.
Pumping Station Design, 2cd ed, Sanks, 1998
Design of Wastewater and Stormwater Pumping Stations - MOP FD-4. WEF, 1993.
Wastewater Engineering: Collection and Pumping of Wastewater. Metcalf & Eddy, Inc., McGraw-Hill, 1981.
Design and Construction of Sanitary & Storm Sewers - MOP 9. WEF, 1969.
Design Manual for Odor and Corrosion Control in Sanitary Sewerage Systems and Treatment Plants, EPA/625/1-85/018, October 1985

***ASCE is currently developing a guidance manual that will address protocols for identifying SSOs. A draft of the manual is expected in 1999.

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