July Newsline: EPA Rules to Reduce Effects of SSOs, DC Solving CSOs and More--Plus Web Exclusives

July 2010 Vol. 65 No. 7

EPA to initiate rulemaking to reduce harmful effects of SSOs
The U.S. Environmental Protection Agency (EPA) is initiating a rulemaking to better protect the environment and public health from the harmful effects of sanitary sewer overflows (SSOs) and basement backups. In many cities, SSOs and basement backups occur because of blockages, broken pipes and excessive water flowing into the pipes. SSOs present environmental and health problems because they discharge untreated wastewater that contains bacteria, viruses, suspended solids, toxics, trash and other pollutants into waterways. These overflows may also contribute to beach closures, shellfish bed closures, contamination of drinking water supplies and other environmental and health concerns.

Infrastructure issues were discussed at the Coming Together for Clean Water Conference held by EPA Administrator Lisa P. Jackson on April 15. The agency plans to address these issues as part of its efforts to protect public health and revitalize local waterways.

EPA is considering two possible modifications to existing regulations: (1) establishing standard National Pollutant Discharge Elimination System (NPDES) permit conditions for publicly owned treatment works (POTWs) permits that specifically address sanitary sewer collection systems and SSOs; and (2) clarifying the regulatory framework for applying NPDES permit conditions to municipal satellite collection systems. Municipal satellite collection systems are sanitary sewers owned or operated by a municipality that conveys wastewater to a POTW operated by a different municipality. As a part of this effort, the agency is also considering whether to address long-standing questions about peak wet weather flows at municipal wastewater treatment plants to allow for a holistic, integrated approach to reducing SSOs while at the same time addressing peak flows at POTWs.

D.C. looks for new ways to solve CSOs
The District of Columbia Water and Sewer Authority is in the process of designing a deep tunnel system to capture and store combined stormwater and sewage for later treatment.

During periods of heavy rain, the system overflows with a mix of untreated stormwater and sewage. The excess pours through outfall points directly into the Anacostia River, Potomac River and Rock Creek. It also overwhelms the advanced wastewater treatment plant at Blue Plains.