Sanitary sewer overflow: Difference between revisions

Revision as of 19:22, 22 September 2020

Revision as of 21:29, 15 December 2020

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===Engineering aspects===

[[Image:Aparissewer.jpg|thumb|230px|Sanitary sewer line in [[Paris]] more than two meters in diameter.]]

Sewers that were built in the early stages of urbanization were usually built before [[sewage treatment]] was implemented.<ref>''See'' [[History of water supply and sanitation]].</ref> Early sewers were simple drainage systems to remove [[surface runoff]] with any waste material it might contain. These drainage systems became [[combined sewers]] when sewage from kitchens, baths, and toilets was added; and the discharge became offensive. Early sewage treatment plants were built to treat the sewage during dry weather; but it was infeasible to treat the larger volume of mixed sewage and precipitation runoff from combined sewers during wet weather. Some cities built sanitary sewers to keep sewage from being mixed with surface runoff so the sewage could be efficiently treated during both wet and dry weather.<ref>{{cite book |last=Okun |first=Daniel A. |authorlink = |title =Sewage Treatment Plant Design |publisher =[[American Society of Civil Engineers]] and Water Pollution Control Federation |volume = |edition = |date =1959 |___location = |page =6 |isbn =}}</ref> (About 860 communities in the U.S. continue to use combined sewers.<ref>{{cite web |url=https://www.epa.gov/npdes/combined-sewer-overflow-frequent-questions |title=Combined Sewer Overflow Frequent Questions |author=<!--Staff writer(s); no by-line.--> |date=2017-12-20 |website=National Pollutant Discharge Elimination System |publisher=EPA}}</ref>)

===Blockages===