Study On Optimal Layout And Function Enhancement Of Storage Tanks For Initial Rainwater

The initial rainwater contains a lot of pollutants due to the erosion of the air and the ground,which has become the main non-point source pollution in the city,which seriously affects the water environment.The rainwater storage tank is an important facility to mitigate the initial rainwater pollution.The research and application of rainwater storage tanks in my country is not mature enough,especially in the planning and layout of rainwater storage tanks and the reduction of volume by strengthening the purification effect of rainwater storage tanks.In order to solve these two problems,on the basis of studying the characteristics of initial rainwater pollution,this topic builds a SWMM model of the research area,and uses the SWMM model to simulate the control effects of different rainwater storage tank layout methods on peak rainwater runoff and initial rainwater pollution.Explore the optimization method of rainwater storage tank layout.A pilot test of air floatation was conducted to investigate the basic operating parameters and purification effect of the rainwater in the early stage of air floatation treatment,and to conceptually design the air floatation-enhanced rainwater storage tank.Study the characteristics of initial rainwater pollution.Through monitoring and analysis of the water quality and quantity of rainwater runoff in the study area,the regularity of the change of the typical pollutant concentration of the initial rainwater with time and the average concentration of the initial rainwater are obtained,and the initial rainwater is defined as the part of the runoff during the first 15?20 minutes after the runoff.Correlation analysis of SS and other pollutants found that SS is strongly correlated with other pollutants.The pollutants in rainwater runoff mainly exist in the form of solid suspended solids.Through the analysis of the M(V)curve,it is found that most of the initial scouring effect occurs in the first 30% of rainwater runoff.Construct the SWMM model of the research area.Statistics of the certainty parameters and sensitivity analysis of the uncertainty parameters,the high sensitivity parameter impermeable area Manning coefficient and impermeable area sag storage rate,the rate of fixed values are 0.013 and 2.000,making the constructed SWMM model accurate and reliable.In the constructed model,the layout optimization method of rainwater storage tank is studied.Mainly simulate the different layout methods of rainwater storage tanks,investigate the effects of rainwater storage tanks on the control of rainwater flow and initial rainwater pollution under different collection and distribution levels,and find that the higher the degree of dispersion of rainwater storage tanks,the better the effect of initial rainwater pollution control.For different connection methods,the layout of the series connection of rainwater storage tanks has better control effect on the initial rainwater flow and initial rainwater pollution than other connection methods.Research on air floatation-enhanced rainwater storage tanks.Through the air float pilot test,determine the operating parameters of the air float device.Choose PAC as coagulant,the best dosage is 40?50 mg/L,and the best dosage of PAM is 2 mg/L.The effluent SS,TP,and COD have good water quality,and meet the surface V discharge standards.Conceptual design of air floatation-enhanced rainwater storage tank,and calculation and analysis of its applicability.