Pollutant Source Apportionment of Combined Sewer Overflows for a Pump Lifting Drainage System

Abstract:

Origins of pollution loads of SS，NH4+ N from total wet weather flows and the overflows from a pump lifting combined sewer system in Shanghai were analyzed with the method of the entry exit mass balance, respectively, based on simultaneously quantity and quality monitoring of surface runoff, sanitary sewage, intercepted wet weather flow and sewer overflow. Compared with the origins of SS , NH4+ N in wet weather flow from 6 monitored rainfall/overflow events, the origins of the two pollutants in CSO were different: the surface runoff contribution decreased by 10.2%～25.1% and 4.5%～11.0%, respectively; the sanitary sewage contribution decreased by 0.3%～1.5% and 6.0%～30.7%, respectively; while the sewer deposits contribution increased by 11.2%～25.4% and 6.8%～37.2%, respectively. Reasons of the difference were analyzed. The results provide a better method to apportion wet weather pollution suffered by urban receiving water, and help to make reasonable decisions to control CSO pollution.

Key words:combined sewer overflows; wet weather flows; entry exit mass balance method; sewer storage quantity; source apportionment