The Study Of Rainwater Utilization In Hefei Residential

Hefei has the rapid development of urban economy as one of the important cities to undertake the transfer of national industries. This makes the growing demand for fresh water resources increase in Hefei, the tension of urban fresh water resources continues.Rainwater resources of Hefei is relatively abundant, according to Hefei city construction land planning, by 2020, Hefei residential land planning area is 9841.39 ha, rainwater utilization potentiality of land used for urban construction. Residential area is as one of relatively frequent area residents in city, the daily water consumption is huge, study of Hefei city residential rainwater to use can alleviate the shortage of fresh water resource is in Hefei.The author collected six fields rainwater of three different types of underlying surface(roof, green land, road) in Binhu new residential area in Hefei based on the meteorological data from 1954 to 2013, of these four long rainfall has carried on the determination of the late rain, and analyzed SS, COD, TN, TP the four kinds of pollutant indexes. Three kinds of pollutant concentration curves of underlying surface in different rainfall days are plotted.Analysis the similarities and differences of SS, COD, TN and TP concentration in the different types of underlying surface storm runoff with the extended rainfall change curve.Later the data were further analyzed, various pollutants of four rainfall at the same time concentration were mean value calculation. Draw three kinds of underlying surface in different rainfall average flow pollutant concentration change curve. Analysis of the underlying surface rainfall runoff and water quality from the perspective of overall to verify whether there is a biggish error analysis results. Overall, water quality of the roof is better in the district, the use of subsequent processing requirements for roof runoff is relatively simple, rain water quality of roads is the worst, and its processing is the relatively complex. Under the early rain flushing action, stormwater pollutant concentrations decreased more significantly in overall different types of pad surface in runoff 20 min, which shows reasonable abandon flow can reduce work load of the subsequent stormwater treatment facilities. The water quality data is further analyzed, and the similarity law of the different underlying surface contamination and the intrinsic relation can be reflected from different angles. Analysis the relativity of SS, COD, TN and TP in the rain in underlying surface during different rainfall, it can be seen that SS,COD,TN and TP are at a higher level and removal of SS in the rain to purify rain water qualityhas great significance as a whole.Through the research results of the relevant scholars, the permeability of the soil layer is improved, and the permeability coefficient of the mixed soil is improved. The roof rainwater collecting has a relatively large simplicity compared with other two kinds of pad surface. Green space, as one of the residential area of common module, the surface of the green vegetation has good adsorption and intercept of rain water pollutants and the underground soil has purification effect on infiltration rainwater. Using rainwater by green space infiltration rainwater is more potential and puts forward the specific schemes of rainwater utilization for the residential road in Hefei.According to the current residential rainwater utilization, and considering the increasingly serious air pollution in Hefei, put forward green roof rainwater utilization mode one of the highest benefits social and economic, and compared with ordinary roof rainwater utilization mode two. And according to the actual case of Hefei District, the rainwater use engineering design, make the economic evaluation of the indirect economic benefits of green roof: Absorption of carbon dioxide economic benefits M1, Oxygen production economic benefit M2, Improve the economic benefit of land utilization M3,Economic benefit of adsorption dust M4, economic benefits of absorption sulfur dioxide M5, Economic benefit of energy saving M6. The direct and indirect economic value of the utilization of green roof rainwater is calculated.The cost and benefit of two kinds of roof rainwater utilization schemes are analyzed,and the feasibility of two schemes from different angles is considered. The static payback period of green roof rainwater utilization project is 1.47 years from the perspective of social, the static payback period of the ordinary roof rainwater utilization project is 4.31 years. Social and economic benefits of them are obvious, and the social and economic benefits of green roof rainwater utilization has the advantages.