CMOM Is Coming, We Can Help

by: Susan McHugh, Marsh-McBirney, Inc.

The United States Environmental Protection Agency (EPA) continues to develop proposed National Pollutant Discharge Elimination System (NPDES) permit requirements for capacity, management, operation and maintenance (CMOM) programs for municipal sanitary sewer collection systems. The current EPA regulations (Part 122 EPA Administered Permit Program; NPDES) have been modified with specific reference to Municipal Satellite Sewer Collection Systems, Municipal Sanitary Sewer Systems, Capacity, Management, Operation and Management Programs (CMOM), Prohibition on Municipal Sanitary Sewer System Discharges, and Record Keeping and Reporting for Municipal Sanitary Sewer Systems. CMOM will affect all separate sanitary sewer systems including satellite collection systems.

General Overview of the New CMOM Regulations
The new regulations are establishing a regulatory framework for applying NPDES permits to municipal satellite collection systems: sanitary sewers owned or operated by a municipality that convey wastewater to a publicly owned treatment works (POTW) that has a treatment plant owned or operated by a different municipality. Poorly performing satellite collection systems often contribute to sanitary sewer overflows (SSOs) which go unreported to the NPDES authority and are often a major contributor to peak flow problems in regional collection systems. The new permit conditions will include recordkeeping, reporting, public notification, Capacity Assurance, Management, Operation and Maintenance (CMOM), emergency response, and audit requirements for all municipal sanitary sewer collection systems.

There are four major documentation requirements of the CMOM permit. Documentation requirements will vary based on the size and complexity of the municipal wastewater collection system and will include:

1. A written summary of the CMOM Program

2. An Overflow Emergency Response Plan

3. A Program Audit Report

4. A System Evaluation and Capacity Assurance Plan

Addressing the Prohibition of Sanitary Sewer Overflow (SSO) Discharges for CMOM
Within the new ruling, there is a general prohibition of SSO discharges. Essentially, if a SSO occurs, the Permittee must demonstrate that the overflow was unavoidable, that the CMOM was in place and working, and that all reasonable steps were taken to stop and mitigate the impact of the discharge as quickly as possible. Under the new rules, owners must properly manage systems at all times by providing adequate capacity for peak flows in all parts of the system, taking all feasible steps to:

• Mitigate SSOs
• Keep written records on SSOs
• Report on Discharge Monitoring Reports
• Provide 24-hour reporting of SSOs
• Keep written follow-up records
• Provide public notification of SSO or backup
• Prepare an annual report
• Develop a CMOM audit program
• Make the CMOM available for public review

This program will require owner certification that all appropriate measures are being taken to eliminate unauthorized SSOs and backups, and that the CMOM Program is being followed and implemented. In order to address the variety of SSO problems, EPA and the States will be targeting facilities where sewage overflows cause or have the potential to cause problems due to poor O&M practices. Facilities need to conduct a thorough self-audit and assessment of their entire sewer system and develop a plan to correct problems over a reasonable time period.

Quick Links for this Article:

Part 1 - General Overview

Part 2 - Why Flow Monitor for Sanitary Sewer Assessment?

Part 3 - EPA Checklists

Part 4 - The How-Toâs of Flow Metering for CMOM Compliance