| Amocng various of pollutants consisting in urban stormwater ru noff,nutrient salts(N,P)are received much concern which are major causes of water eutrophication.Thereinto,P is considered as the main limiting factors for water eutrophication.Therefore,to seek an ceonomic nd convenient way for governance is the key point about urban stormwater runoff pollution control and urban streams eutrophication risk reduction.Through exploration andpractice for many years,stormwater management system has had a great development.Bioretetenion syeysere is proved as high-efficient urban stormwater control measure.And,it plays an important role for runoff volurne redution and pollition purification.After lage amounts of investion and analysis,DP(Dissolved Phosphorus)exists inSRP(Soluble Reactive Phosphorus)form at roof and road stormwarer runooff.4 pilotbioretention devicese(7#,8#,9#and 10#)was selected for influene factors effect test,intermittent running effect test,and continuous running depletion test respectively Thepyrifying effect for SRP in bioretention was studied;the correlativity between influencefactors and SRP removal efficiency was explored on the basis of PLS(Partial Least Regresssion);various bioretention facilities were ssleccted and monitored for stormwater runoff cooming from different underlayer surface,,an runoff volume reduction and different phosphorus forms pollution purification of bioretention facility were analyzed;for thedeficiency of bioretention facility operatioon ffect during natural rainfall processes,batch experiment was conducted in order to provide reference idea for he promotion of bioretentionfacility operation effect.Main conclusions of this study are as follows:(1)Eight sesisions experiments on the influence factors and its effect,water volumereduction rate of 7#bioretention device(artificial filler level:Fly ash+sand),#9(artificial filler level:blast furnace slag),10#(artificial filler level:pure planter earth)bioretention devices mostly are higher than 40%,but peak flow reduction of 9#(artificial filler level:blast furnace slag)are far from satisfactory resulting from large particle size filler;Load reduction rates of three kind of medias in different bioretention devices for SRP pollutant are obvious otherness,and removal efficiency of 7#is optimal closely followed by 9#and 10#;SRP concentration process lines of effluent are also obvious otherness,and SRP concentration process line of 7#is quite stable while 9#and 10#are volatile at some degree;during continuous running depletion test,the purifying effect for SRP of 7#is never lost,but 9#and 10#are the opposite with SRP fast adsorption taking the lead.(2)For inner and external influence factors,combining the establishment of equivalent temporation adsorption model for three kinds of filler combination,saturated adsorption capacity of filler combination and adsorption bond strength are found as key factors for SRP removal efficiency at bioretention based on PLS.(3)By monitoring runoff volume reduction and pollution purification of bioretention facilities which are able control stormwater runoff coming from different underlayer surface during natural rainfall processes,bioretention facilities with soil and sand as main substrates are good at runoff volume reduction and pollution purification.But,the pollution purification for P is less than satisfactory,and the P in effluent is mainly dissolved form.(4)6 kinds of experimental filler amendments(pelelith,maifanite,little ceramsite,turfy soil,vermiculite and water treatment residues)were selected,by equivalent temporation adsorbing test,Langmuir equation is found that does a fine job of describing equivalent temporation adsorbing characteristic for P of 6 kinds of experimental filler amendments.Thereinto,saturated adsorption capacity(2.824 g/kg)and adsorption bond strength of WTR for P are superior to other 5 kinds of experimental filler amendments,and WTR shows potential for P adsorption;the effect of WTR for P adsorption is of great stability while it's difficult to desorb;by studying the adsorption kinetics of WTR and flyash,it's obtained that the effect of WTR for P adsorption rate is slightly advantageous. |
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