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PROPOSED EPA SSO RULE AND THE NATIONAL SSO PROBLEM
Citation:
Field*, R AND D Lai*. PROPOSED EPA SSO RULE AND THE NATIONAL SSO PROBLEM. Presented at ASCE World Water and Environmental Resources Congress, Orlando, FL, 5/20-24/2001.
Description:
It is estimated there are about 40,000 sanitary-sewer overflow (SSO) events nationwide yearly. In 1995, 65% of the 79 large municipalities responding to a national survey experiences SSOs. Another study estimated that approximately 75% of the nation's SS systems function at 50% of capacity or less and that sewer pipeline stoppages and callapses are increasing 3% yearly. SSOs result in releases of raw sewage to streets, private property, basements and receiving waters. Untreated SSOs can contain high levels of pathogenic microorganisms, suspended solids, toxic pollutants, floatables, nutrients, oxygen-demanding organic compounds, oil, grease, and other pollutants, Potential halth and environmental tisks associated with poor performance of many of these systems highlight the need to increase federal regulatory oversight of the management, operation, and maintenance of these systems. EPA will issue a SSO Rule by the end of 2000 that will add control and mitigation of SSO to the NPDES permit requirements. The proposed SSO Rule will add the following requirements to the NPDES permit of a publicly owned treatment works (POTW) serving sanitary sewer collection systems: Capacity, management, operation and maintenance (CMOM) program for municipal sanitary sewer collection systems; prohibition on municipal sanitary sewer system discharges; reporting, record keeping and public notification requirements for municipal sanitary sewer collection and SSO and; remote treatment facilities. The CMOM program specifies that municipalities must conduct inflow elimination or reduction, cost-effective sewer rehabilitation, and collection system inspection with associated clean out and repair. Since bulding connection lateral sewers contribute 79-80% of I/I, a significant amount of I/I will not be abated even after a proer operation, maintenance and rehabilitation of the street sewers. This remaining I/I wopuld have to be included to meet the requirements that municipalities must develop a capacity assurance plan to convey peak wet-weather flow and a plan to mitigate SSO.