Approximate BOD Treatment Requirements for Urban Runoff

The impact of storm-induced flows on receiving water dissolved oxygen levels is investigated for nine selected urban areas. Included are sites subject to combined sewer overflow as well as sites subject to storm-water runoff. The resulting DO sag curves are analyzed and BOD treatment requirements for the storm-induced BOD loading are identified for each study site. Treatment requirements are based on the criterion of maintaining a minimum DO residual in the receiving water of 5.0 mg/l. The identified treatment requirements together with pertinent site-specific wasteloading and receiving water characteristics are analyzed by regression techniques in order to develop a lumped areawide water quality index. This index can be used to estimate urban runoff BOD treatment requirements for locations with known wasteloading and hydrologic characteristics.