Research on Pollution Characteristic of Urban Runoff in Storm Sewer

Taking urban roof as the catchment area in Xinxiang City, researching on the hydrology and water quality process of each rainfall event in storm sewer can provide the basis for effectively using urban rainfall and controlling non-point source pollution, and so on. The samples were taken to analyze the contents of SS, COD and TN. The results show that the variation trend of pollutant index SS, COD in runoff is similar and tends to be a steady value. TN decreased with the accumulation of rainfall, but rebounded before the end of rainfall. The standard deviation rate of water quality indicator is SS > COD > TN. The roof flush effect is obvious at the initial stage of runoff, and the initial runoff amount can be defined as the first 1-3mm rainfall. The correlation of SS, COD and TN is good in runoff, and measures can be taken to remove them simultaneously in controlling the runoff pollution. The runoff pollutants flow into the receiving water directly through urban drainage pipe network, and have a great effect on its water quality, especially the changes of SS and COD are the most obvious.