Experimental Study On The Treatment Of Urban Runoff And Rainwater In The Process Of Multilayer Infiltration Medium System

Currently,in the face of the water environment of China is in shortage of water resources,serious water pollution,flood disasters occurred frequently,the situation is urgent to be the rationalization and effective utilization of rainwater resource is a sustainable development measures.Through analyzing the present situation of rainwater utilization,the paper makes a thorough study on the technology of rainwater utilization,and then uses the multi-stage filtration media to filter the groundwater and rainwater reuse as the target,research on multistage filtrationmedia filtration by filtration method.The experimental apparatus of the filtration medium was constructed by using the ceramic,quartz sand,coconut shell activated carbon and volcanic rocks as the experimental apparatus.After the optimization of single medium,the combination scheme of multistage filtration medium system is determined.According to the actual situation of the possible occurrence of the 5 factors,through the analysis of the factors affecting the composite media,the impact of possible factors on the multi-stage filtration system.The main conclusions are obtained by the optimization of single medium:the removal rate of NH₄⁺ in 4 kinds of filter media is in the order of high and low:coconut shell activated volcanic rock>carbon>quartz sand>ceramsite;on the removal rate of TP high and low order as:coconut shell activated carbon>ceramsite>volcanic rock>quartz sand;on the removal rate of COD high and low order as:coconut shell activated carbon>volcanic rock>ceramsite>quartz sand;on the removal rate of SS high and low order as:coconut shell activated carbon>ceramsite>quartz sand>volcanic rock.Any combination of two or four filter,any three combination can be treatment effect on 4 kinds of rainwater indicator.According to the results of the optimization of the leachate,4 composite solutions were combined to compare the treatment effect of 4 kinds of combined treatment,the main conclusions are as following;the average removal rates of NH₄⁺,TP,COD,and SS were 57.5%,82.2%,66.4%and 85.0%by the combination scheme of carbon and rock,the average removal rates of NH₄⁺,TP,COD,and SS were 56.7%,78.4%,62.3%and 73.2%by the blending scheme of carbon and rock,the removal effect of coconut shell activated carbon and volcanic rock is better than that of the mixture.The average removal rates of NH₄⁺,TP,COD,and SS were 44.8%,68.2%,41.9%and 70.1%by the combination scheme of sand,carbon and rock,the average removal rates of NH₄⁺,TP,COD,and SS were 39.6%,60.0%,33.2%and 67.1%by the combination scheme of ceramic,carbon and rock,the effects of quartz sand,coconut shell activated carbon and volcanic rocks on the removal of pollutants are better than those of the three kinds of filter media,such as ceramic,coconut shell activated carbon and volcanic rocks.According to the effect of 4 kinds of composite media on the treatment of urban runoff,selection carbon and rock combination scheme as the factor analysis object,the main conclusions are:the removal effect of pollutants in runoff and rain water was the best at the beginning of 15minute,the average removal rates of NH₄⁺,TP,COD,and SS were 62.5%,81.0%,62.7%and 89.6%.The average removal rates of the four pollutants in high concentrations were improved,and the average removal rates of NH₄⁺,COD,TP and SS were increased by 2.8%,6.6%,14.7%and 0.5%.The average removal rates of NH₄⁺,TP,COD and SS decreased by 3.0%,11.6%,4.9%and 3.3%respectively in the continuous operation.The average removal rates of NH₄⁺ and TP were decreased by 5.6%and 11.3%respectively,and the average removal rates of COD and SS were increased by 0.8%and 0.5%when the filtration rate increased from 0.57m/h to 2.26m/h.The average removal rates of NH₄⁺ and TP were increased by 7.3%and 1.6%respectively,and the average removal rates of COD and SS were decreased by 6.3%and 2.5%respectively,when the thickness of the medium is increased from 400mm to 800mm.