The Study Of Rain Comprehensive Utilization In Changsha Area

Residential area as an important carrier of the city, the rainwater comprehensiveutilization is one of the important research direction of city rainwater utilization.Theauthor has researched the present situation and development tendency of urbanrainwater utilization at home and abroad in this topic, and has summarized andperfected the concept, characteristic, principle and technology of urban rainwaterutilization, at the same time the role of reducing pollution of urban rainwaterutilization has be preliminary discussed in the topic，on the basis of which the topichas calculated and analysed the rainwater utilization potential and the existingproblem of Changsha city.Finally the author has researched the effects which thesystem-penetrative U drains and porous filtration tube which was developed by theBeijing taining kechuang technology Co., LTD. has produced to rain and has donewater balance analysis and comprehensive evaluation of the urban rainwaterutilization.The results of the study show that:Firstly, in Changsha city, average annual precipitation is1422.4mm, and thepeople can collect about0.611million m3, the rainwater utilization has greatpotential.Secondly, the purify effect which the soil after embedding filtration system hasproduced to rain is superior to the effect which the original state of soil has done. Theremoval rate for COD、ammonia nitrogen （NH₄⁺—N）、nitrate nitrogen（NO₃^-—N）can respectively increase to19.84%,18.43%and17.05%, and the removal rate for thetotal phosphorus （TP） can elementaryly increase to5%.The infiltration capacity whichthe soil has produced to rain can be have improved after the filtration system has beembedded in the soil, which has the comprehensive effect for reducing the runoff andset flow and cutting pollution load and has the important role to improve soilinfiltration performance, control runoff pollution.Therefore, from above a fewremoval efficiency of index and runoff reduction, we can consider to promote theinfiltration function U drains and HDPE porous filtration tube as rainwater drainage pipe which has the increased permeability function and was developed by theBeijing Taining Kechuang technology Co., LTD. in Changsha city.Thirdly, the years available rain water of the area which is involved in the subjectcan fully satisfy the requirements of miscellaneous water, and the excess rainwatercan also be used for other purposes, which can effectively reduce the the amount ofwater of foreign emissions and improve water use efficiency in the village.Fourthly, the community rainwater utilization has good economic benefit andsocial benefit and the ecological environment benefit, the research results of thesubject has a very good reference to promote urban district rainwater utilization.