RUNOFF POLLUTION SIMULATION OF INTERCEPTED COMBINED SEWER SYSTEM

Load estimation of the combined sewer overflows(CSOs) from the intercepted combined sewer system is quite difficult,because CSOs usually happened in large rainfall and storm events and lack of observed data.Based on investigation of sewer discharge networks,meteorological data and land use map,SWMM model was developed for the catchment of western wastewater treatment plant(WWTP) in Yingkou City,and was calibrated and validated using observed water flow and quality data at inlet station of WWTP.CSOs simulation data showed that rainfall amount was a very important factor for urban runoff pollution,but it was not the unique factor.Rainfall retention period,rainfall intensity and dry period prior to rainfall event all influenced greatly the runoff pollutant loads of CSOs.Data also showed that water flow and pollutant load of CSOs were correlated with rainfall amount.