What is a “combined” sewer/stormwater system?
Sanitary sewers carry waste from homes and industrial users. Stormwater sewers carry water from stormwater (rain or snow) events and usually by-pass treatment. In most cases, these are completely separate systems. However, in some areas of Kansas City the stormwater systems are “combined” with sanitary sewers. Under normal or “dry” conditions they operate with the sanitary portion going to the treatment facility, but when large amounts of rain occur the system can go into “by-pass mode” to help control flooding. At such times the sanitary portion becomes mixed and heavily diluted with stormwater and a portion of the mixture may “by-pass” treatment and go directly to the receiving water.
