Study On Compound Pollution Controlling Of Rainwater System In An Industrial Park

The compound pollution of rainwater system in industrial park is taken as the research object.By constructing rainwater and landscape water body model,simulating rainfall situation at different periods and before and after adding dry season pollution and analysising the changes of pollutants and their impact on the receiving water.Finally,the measures to control the compound pollution of rainwater have been proposed and the model is used to analyze the effect of the control measures of compound pollution of rainwater.According to the rainwater pipe layout of the study area,monitoring points of water quality were arranged.The monitoring indexes were COD,ammonia nitrogen and total phosphorus,and sampling in January,April,June,July,August,September and November of 2016 year.The comprehensive pollution index method was used to analyze and evaluate the water quality.Through seven times of water quality monitoring,the situation of drought rainwater quality in 2016 was analyzed comprehensively,and the serious polluted sites and suggested monitoring sections were proposed.The rainwater runoff water quality model was established to simulate the process of rainfall production and distribution and pipe network transmission.The rainfall recurrence period was set to 0.25 year,0.5 years,1 years,3 years,5 years,20 years,the duration of rainfall was 120 minutes.The model can simulate the flow changes of rainwater system discharge and test the ability of rainwater pipe network;Simulating the water quality?COD,NH₃-N,TP?of joining the dry flow pollution before and after.The simulation results show that the pollution proportion of the dry flow is larger than that in the total pollution,and the trend of the runoff pollutant index is basically the same,and the obvious single peak appears.According to the data of the artificial water of the study area,the monitoring of the artificial water was carried out in 1,4,6,7,8,9 and 11 month respectively in 2016.The water quality monitoring indicators included pH value,chemical oxygen demand,total nitrogen,total phosphorus,water temperature,chlorophyll a and dissolved oxygen.The results showed that the eastern landscape water of the study area was light pollution water by comprehensive weighted evaluation methods.Based on the monitoring and evaluation,the WASP landscape water quality model was established.Taking the rainfall in a year as an example,the effect of compound rainwater pollution on the water receiving body was simulated.The simulation results show that the pollution degree of the rainwater in the early stage is serious,and the discharge of pollutants into the receiving water bodies will have the peak at each index,and the rainwater pollutants at the later stage will be lower than the background concentration of the receiving water,so the pollutant concentration curve will decrease.The countermeasures of rainwater compound pollution control have been proposed:Source control?low impact development measures?,process control?rainwater network dredging?and end control?rainwater storage tanks?,and gives the scale of the measures.Based on this,the SWMM and WASP models were used to simulate the measures and the effect of the comprehensive measures.The simulation results show that the low-impact development measures can reduce the runoff and pollutant concentration,the dredging measures of the rainwater pipeline can reduce the accumulation of the dry season,and the rainwater storage reservoir has the interception effect on the early rainwater,and verified the feasibility and effect of the measures.