Study And Application Of Rainwater Resources Based On Low Impact Development

Urbanization has brought economic growth but also negative effects: urban sprawl,and population growth,increasing pressure on urban water resources;city size get bigger,hardened underlay surface gradually increase,rainwater infiltration become difficult,serious affect the natural hydrological cycle,cause spark urban waterlogging,urban stormwater runoff pollution flow into inland lakes,and groundwater level decline and other ecological problems.Rain water as natural resources with advantages of non-depletion,cleaner water,simple handling and so on.The utilization of urban rainwater in roof rainwater harvesting was investigated in the study.A large number of reference materials and the latest research results analyzed and the technical route of this study was established: First,a full investigation in terms of hydrology,meteorology,geology,etc.about the study area-Wuhan was conducted;the roof of sun room in Resource and Environment College of Wuhan University of Technology was used as the testing ground for the study of water quality characteristics of roof rainwater in this region;the roof rainwater purification system equipment and pilot programs we designed base on the water quality study;the experimental study of the device operation in actual working conditions.The main test results and conclusions are summarized as follows:(1)Concluded many years of meteorological data show that the study area Wuhan is abundant rainfall city,the average annual rainfall reaches 1285 mm,but seasonal differences are significant,the rainy season is spread from March to August,from May to July in which rainfall is most abundant;(2)Study of the regional water quality characteristics found: The roof runoff pollutant content changed much,the water quality was unstable,with the rainfall extending,the pollutant concentration of rainwater reduced and become stable gradually;Former rain within 1~2 h,roofing rainwater pollution was more serious,that the initial storm water runoff due to rain erosion effects and combined with atmospheric pollutants made the pollutants into the maximum;Initial roof stormwater pollution was more serious,SS,Turbidity,COD,TN,TP mean to 44.13 mg/L,32.6 NTU,35.08 mg/L,9.1 mg/L,0.6 mg/L,respectively,not reached the “Surface Water Environmental Quality Standards" ? class water requirements,the peak was more than ? class water requirements three times,did not meet the "Reuse of Recycling Water for Urban Water Quality Standard for Urban Miscellaneous Water Consumption" the basic requirements,can not be reused directly;Later roof rainwater pollution reduced significantly,SS,Turbidity,COD,TN,TP mean to 15.35 mg/L,8.26 NTU,17.27 mg/L,5.9 mg/L,0.3 mg/L,respectively,the indicators reach ?~? class water requirements basically,but TN still exceeded more;(3)Based on the study of the roofing quality characteristics,according to comparing the alternatives,and full integrated of low-impact development(LID),established the craft of rainwater wetland/ACF(Activated Carbon Fiber)filter dynamic combination,treated the initial stormwater runoff and late rainwater runoff,respectively;(4)The experiment on actual operation of the device that used the craft of rainwater wetland /ACF filter to treat the initial stormwater runoff,the average removal rate of SS was 82.36%,COD 57.13%,TN 80.41%,TP 63.31%,the effluent index of SS had reached the "Reuse of Recycling Water for Urban Water Quality Standard for Urban Miscellaneous Water Consumption" as domestic miscellaneous water standard,COD,TN,TP had reached the "Surface Water Environmental Quality Standard" in class III water requirements basically;ACF by direct filtration process on late roof runoff treatment effect: SS removal reached 42.51%,COD reached 17.55%,the removal rate of TN?TP were 54.87% and 23.33%.After ACF filter,SS,COD,TN,TP indexes were 11.53 mg/L,13.21 mg/L,1.4 mg/L,0.18 mg/L,respectively,due to the late roof rainwater itself was clean relatively,had recycling conditions basically,so removal effect was not very obvious,lifting amplitude was litter compared with the initial rainwater smaller on water quality,using ACF filter was to improve the water quality more,mete the higher requirements,in general,after the ACF adsorption filtration,late roof runoff quality have further enhancing,the indicators reached III class surface water standards,which some indicators even reached class I and II water quality index limits,can be as an urban miscellaneous water.