Study On Non-point Source Pollution Reduction Technology In Typical Cities Of Taihu Lake Basin

Currently,the problem of urban non-point source pollution is serious.The non-point source pollution with strong randomness is difficult to control because of many influence factors.Based on the urban non-point source pollution,this paper is devoted to the study the time and space distribution characteristics of rainfall runoff pollution,the initial scouring effect,the analysis of pollutant sources and the average non-point source pollutant load in different underlying surface of Yixing.Based on this,we study the effect of water quality and quantity of rainwater garden by slashing non-point source pollution by the experiment.The main contents and achievements are as follows:?1?The concentration of rainfall runoff pollution of the roof is significantly lower than that of the road.The turbidity,COD,TN,ammonia nitrogen and TP were respectively 60.7 NTU,73 mg/L,1.99 mg/L,0.62 mg/L,0.33 mg/L of the roof.The turbidity,COD,TN,ammonia nitrogen and TP were respectively 63.59-240.69 NTU?68.63-423.21 mg/L?2.76-10.93 mg/L?0.82-2.35 mg/L?0.22-1.77 mg/L of the road.The initial concentrations of COD,TN and TP of the three underlying surface?including Feili roof,Donghe road,Lvyuan road?are higher than the standard values of the ?Surface Water Environmental Quality Standard? V standard.The difference of runoff pollution concentration of different underlying surface is also obvious.The pollution degree of Donghe Road garbage station is much higher than the other two underlying surface.The COD and TP of runoff pollutants in Yixing city have obvious correlation with turbidity,and the correlation between nitrogen source pollutants and turbidity is relatively small.At the same time,there is a certain degree of erosion effect among three different underlying surface.The annual average non-point source pollution load of the main area in Yixing was analyzed and estimated.The pollution emission of COD,TN,ammonia and TP were respectively 3221.7 t,82.6 t,25.6 t and 11.6 t.?2?The rainfall intensity is negatively correlated with the ability of dealing with runoff contaminants of rainwater gardens in Laboratory simulation.The effect of the treatment of nitrogen source pollutants with the zeolite packing layer is significantly higher than that with the ceramic filler layer.The effect of the treatment of COD and TP with the ceramic filler layer is significantly higher than that with the zeolite packing layer.The modified coating layer has remarkable effect on the ability of dealing with pollution of rainwater garden.Finally,we chose the optimum condition of 0.5 mol/L FeCl₃ solution modified coating layer and zeolite filler eventually.The ability of flood storage capacity of rainwater garden is negatively correlated with rainfall intensity and is positively correlated with dry length.