CSO Storage Tanks Setting Method Based On SWMM

A large number of studies show that the pollution caused by confluence overflow not only harms the ecological environment and human health,but also affects the sustainable development of society.Based on the data analysis of the measured dry days and rainy days of a combined drainage system in Yueyang city,this paper obtains the law and USES it as the basis for SWMM model calibration and parameter checking.Through the simulation of the designed rainfall,this paper compares the setting schemes of two kinds of CSO regulating ponds,providing theoretical reference for the formulation of scientific and reasonable setting schemes of CSO regulating ponds.Through the analysis of the measured data and the simulation study of the model,the following conclusions are drawn in this paper:(1)a comparative analysis was conducted on the variation trend of water flow in the pipe network and the rainfall trend in rainy days.It was found that the variation trend of water flow in the pipe network was roughly the same as that of rainfall,and the upstream and downstream water flow in the pipe network also had a similar variation trend,with the downstream trend lagging slightly behind the upstream trend.(2)through the analysis of each pollutant in different rainfall conditions and different monitoring points,according to the pollutant discharge standard of urban sewage treatment plant(gb18918-2002)level A standard,the pollutant index determined by TP for the volume of CSO storage tank in this paper was determined.(3)in this paper,the centralized distribution mode of CSO storage tank was simulated with nine designed rainfall fields,and it was concluded that: with the increase of rainfall,the total overflow increased;Except for the case that the rainfall reappears once every 0.1 year,the water needed to hold in the storage tank from the beginning of rainfall is shorter and shorter,and the ratio of storage capacity and overflow volume is smaller and smaller.Under the same rainfall duration,the volume of the storage tank does not increase completely with the increase of rainfall depth,but increases first and then decreases.When the recurrence period P≥3,the volume change of the storage tank is not significant.(4)through the comparison of different models to regulate tanks space distribution,found that in addition to design rainfall return period(P = 0.1 storage tanks volume reduction rate is negative,the other design return period,the storage tanks volume reduction rate were greater than 10%,which shows that by changing the location of the storage tanks is set to the storage tanks volume is reduced,so according to the actual storage tanks volume and construction conditions,scattered distribution set the storage tanks is superior to the centralized distribution mode set the storage tanks.