Study On The Relationship Between Factors Influencing Outflow Pollution Of Urban Drainage System And Urban Water Environmental Capacity

In recent years, due to the swift growth of population, rapid economic development and the lack of effective control in sewage treatment and discharge, the problem of river water pollution and functional degradation is becoming increasingly severe. It has become an important factor restricting sustainable social and economic development and the improvement of people’s living standards. Therefore, to better protect the water, the research of water environmental capacity has become a significant subject. Besides, as the basis of urban water pollution control, the research of factors affecting urban drainage system pollution is closely related to the water environmental capacity. Therefore, the research of the relationship between the water environmental capacity and factors affecting urban drainage system pollution is necessary.First of all, the basic theory of water environmental capacity and river water environmental capacity calculation models were summarized.Secondly, from the perspective of statistics, the correlation between the typical urban water pollutants were analyzed, and the water environmental capacity of typical urban river was calculated. Under the current Class V of water standards, the water capacity of COD, NH3-N, TP and TN are 154.27 t/a,5.49 t/a,2.31 t/a and 1.17 t/a.Thirdly, based on case study, the relationship between water environmental, capacity and urban functional zones, urban functional areas and the first flush effect were discussed. The cases showed that, from the point of water environmental capacity, three conclusions were drawn:separated sewerage system was better than combined sewerage system, while combined intercepting system was better than traditional combined sewerage system. As for urban functional zones, the pollution intensity in residential areas exceeded commercial ones and further exceeded administrative ones. The first flush of rainfall had impact on the water environmental capacity within the earliest 5 minutes.