Simulation Study On Urban Runoff Pollution And Pollution Control Effect Of LID Based On SWMM

In the last decades,with the rapid steps of urbanization,there is an increasingly percentage of impervious pavements in cities.Pollutants generated by human activities accumulate on the ground.When rainfall comes,pollutants are flushed and carried by rain runoff,and discharged into the receiving water.The problem of non-point source pollution is widely occurred in China and the quality of urban hydro environment is threatened.It is significant for preventing and controlling urban water pollution to study on the feature of rainwater quality and the pollutant load of discharging.There are many characteristics of urban runoff pollution such as space-time distributing disperses,pollution approach diversity and component complexity etc.Using software model to simulate the regular pattern of pollutants in rain runoff is an important method in the studying of rainwater quality.SWMM is one of the most widely used software among.Build the model of ground surface environment and drainage pipe system of the studying area by SWMM.Select 0.5-year,1-year,3-year,5-year and 10-year for storm returns period,and 120 minutes for duration.COD,TSS,TN,TP are chosen as four kinds of pollutants for the study.Simulate the pollutants' concentration and discharging flow at the outfall in different storm events.The simulation shows the regular pattern of concentration and outflow.According to the result,speculation and analysis of the runoff flushing characteristic are given.And the simulation result can be the basis and reference of the intercepting drainage design.LID is a new measure of runoff pollution source controlling.Pollutants can be removed effectively by LID.LID practice is spread and found in many countries around the world.Four typical LID practice,Bio-retention Cell,Green Roof,Permeable Pavement,Vegetative Swale,are introduced about the structures,conditions and advantages.Simulated the ability of LID in runoff cleaning.The simulation shows the property of each LID practice,and the remove effect for pollutant.A combined LID plan is set and simulated,and advises for LID engineering design are provided according to the result.