Study on overflow pollution characteristics of combined drainage system in plain river network area of Yangtze River basin
In the plain area of the Danjinlicao River Jintan sections were selected to monitor the overflow pollution at three typical combined flow overflow outlets and the pipeline inspection wells.The characteristics of water quality and water quantity changes in the network overflow of the Danjinlicao River Jintan section were analyzed.Simulate flushing tests using sediment in a con-verging pipe as the experimental material to explore the sediment erosion rule.The results showed that the overflow occurred when the accumulated rainfall exceeded 2 mm;The variation in overflow water volume was mainly influenced by rainfall level,rainfall intensity and residential water con-sumption,and the peak overflow volume lagged behind the peak rainfall intensity.The concentra-tion of overflow pollution was directly related to the number of preceding dry days,the nature of the outlets,rainfall level and rainfall intensity.Overall,the concentration exhibited an initial in-crease followed by a decrease trend,and regardless of the type of rainfall,the overflow outlets would experience higher levels of pollution approximately 20-30 minutes after the runoff began.Sediments contribute significantly to overflow pollution.During the flushing process,sediment particles exhibit alternating stages of motion.The peak value of each pollution index appeared after a period of time when the rainfall formed runoff.
万方数据
维普
