Sanitary sewer overflow: Difference between revisions

Revision as of 17:59, 25 September 2015

Revision as of 18:00, 25 September 2015

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===Infiltration/inflow===

Approximately one-quarter of United States SSOs occur during heavy [[rainfall]] events, which can cause inflow of [[stormwater]] into sanitary sewers through damage, improper connections, or flooding buildings and lift stations in low-lying areas of the collection system. The combined flow of sewage and stormwater exceeds the capacity of the sanitary sewer system and sewage is released into homes, businesses and streets.<ref name="EPARTC"/>{{rp|p. 4–26}} This circumstance is most prevalent in older cities whose subsurface infrastructure is quite old; [[Paris]], [[London]], [[Stockholm]],<ref>Monica Spendilow, ''Impeller Magazine'', ITT Flygt AB, SE-174 87 Sundbyberg, Sweden (2004)</ref> [[New York]], [[Washington, DC]], and [[Oakland, California]]<ref>''Environmental Impact Statement for the [[East Bay Municipal Utility District]] Wet Weather Overflow Project'', Earth Metrics Incorporated, prepared for the U.S. EPA and East Bay Municipal Utility District, Oakland, Ca. (1985)</ref> are typical examples of such locations. Inflow into the sanitary lines can be caused by tree root rupture of subsurface lines or by mechanical fracture due to age and overpressure from trucks and buildings above.

Historically, one of the biggest causes of SSO operation is the overloading of the sewer during storms and there has been a call to reduce the amount of water entering sewers by introducing SuDS.

===Malfunctions===