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COMPUTER MODEL ANALYSIS FOR CONTROL PLANNING OF SANITARY-SEWER OVERFLOWS
Citation:
Lai*, D. COMPUTER MODEL ANALYSIS FOR CONTROL PLANNING OF SANITARY-SEWER OVERFLOWS. In Proceedings, 9th International Conference on Urban Drainage, Portland, OR, September 08 - 13, 2002. IWA Publishing, London, Uk, ., (2002).
Impact/Purpose:
information
Description:
The Nation's sanitary-sewer infrastructure is aging with some sewers dating back over 100 years. There are more than 19,500 municipal sanitary-sewer collection systems nationwide serving an estimated 150 million people and comprising about 800,000 km (500,000 mi) of municipally owned sewer lines. There are about 40,000 sanitary-sewer overflow (SSO) events per year nationwide. Potential health and environmental risks 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. The U.S. Environmental Protection Agency (EPA) is preparing to issue a SSO Rule that will add control and mitigation of SSOs to the National Pollutant Discharge Elimination System (NPDES) permit requirements.
The major elements of the SSO Rules are that it requires a SSO municipality to: (1) provide adequate capacity to convey base dry-weather and peak wet-weather flows (WWF) for all parts of the collection system, and (2) take all feasible steps to stop and mitigate the impact of SSOs. Since building connection lateral sewers can contribute as much as 70 to 80% of the total infiltration/inflow (I/I), a significant amount of I/I will not be abated, even after proper operation and maintenance and usual rehabilitration of street sewers only. This remaining I/I must be addressed in the SSO community's capacity assurance plan.