Taking a typical combined flow system district in central URBAN area of Beijing as the research area,the whole process monitoring from"surface,pipe network and outlet"was car-ried out.A numerical model was constructed based on MIKE URBAN software,and a set of over-flow pollution analysis method combining monitoring and model was constructed to quantitatively analyze the sources of overflow pollution under different rainfall levels.The results show that:the contribution rates of pipeline sediment,surface runoff and daily sewage to COD are 43.4％—53.9％,27.4％—27.5％and 18.6％—29.2％,respectively.The peak of moderate rain flow is lat-er than the peak of concentration,and the reverse for heavy rain;The difference of the peak water concentration of the two rainfall overflows is smaller than the peak water flow.With the increase of rainfall level and intensity,the pollution load of surface runoff and pipeline sediment increases,and the latter increases more.Pipeline sediment is the main source of combined overflow pollution,and priority should be given to its control.
维普
万方数据