Study On Collection And Strengthening Treatment Of Rainwater Runoff In The Integrated System

With the accelerated process of urbanization, the area of impermeable zone isincreasing,and the pollution of urban surface water caused by storm runoff has becomethe main reason for water pollution in the city. Longjing Lake of Chongqing GardonExpo is a typical channel reservoir, its water recharge mainly depandes on rainfall. Thecontrol of non-point source pollution is very important for the water quality control ofLongjing Lake. This study focuses on the collection and strengthening treatment ofinitial rainwater and a integrated device without labor need and energy consumptiondesigned.Considering of the rainfall-runoff characteristics, and some current ecological-engineering measures and physicochemical measures for reference, for exampie, InitialRainwater Storage tank, Infitration Pond, EcologicalVegetation， Grassed swales,Constructed Wetland system, an integrated device was designed. The initial rainwater isseparated by the aeparation part of integrated device, then the rainwater inflow theinitial rainwater storage tank and Suspended Particles are removed by precipitationprocess,afer the stop of rainfall, the rainwater of Initial Rainwater Storage tank inflowthe strengthening treatment part and most pollutants can be removed in this part.According to the detection of initial rainwater of Longjing Lake of ChongqingGardon Expo，the main pollutants of rainwater in the catchment of Longjing Lake wereNH4+-N、TN、TP，and can not reach the water quality standard Ⅳ,but CODMnwasbeyond the the water quality standard Ⅳ, the percentage of NH4+-N in Total Nitrogenwas about60%. The aim of the integrated device is the removal of nitrogen andphosphorus.The adsorption properties of Natural Zeolite,Na modified Zeolite,Activated Zeolitefor NH4+-N in the runoff were studied, and the adsorption properties of ActivatedAlumina, Sponge Iron for phosphate in the runoff were studied. The results reveal thatthe Na modified zeolite shows prominent adsorption capability, and its saturatedadsorption capacity is9.09mg/g. Na modified zeolite can be a suitable adsorbent.Theadsorption properties of Sponge Iron shows prominent adsorption capability and itssaturated adsorption capacity is2.42mg/g. The saturated adsorption capacity ofActivated Al2O3is1.04mg/g.The experiment of dynamic adsorption shows that the effect of removing ammonia nitrogen is better than other pollutants in the removing nitrogen part,and NO3-N，TP，COD can not be removed effectively.The contact time, concentration of influent,beddepth are the main parameters which influence the effection of removal.The resultsshowed that the adsorption of NH4+-N could be describe by Bohat-Adams mode,Clarkmode and Thomas mode. The dynamic adsorption of Sponge Iron showed that theadsorption of phosphate could be describe by Bohat-Adams mode.Through the calculation of the effective volume of equipment required dealingwith the same rainfall,the best contact time is10~20min for the NH4+-N removal part,and the best contact time of phosphorus removal part is10~20min, the design of thebed high h>0.25m,, through the optimization of volume for strengthening processingequipment in Garden Expo, the service area of square, road and greenbletrespectively are4327m2,916m2and10086m2，the effective volume of NH4+-N removalpart is9.0m3, the effective volume of phosphorus removal part is10.0m3.