| Rainwater resource utilization can alleviate water shortage,reduce urban intrinsic pollution and control non-point source pollution,and is of great significance to the sustainable development of economy and society.Roof rainwater has become the focus of attention at home and abroad because of its light pollution and easy handling.The layout of campus buildings is concentrated,the green area is large,the demand for miscellaneous water is large,and the utilization rate of rainwater is high,which is more suitable for rainwater resources utilization.There are many scientific research institutions in Xi'an,and the campus has a large area.It is of great significance to carry out research on the utilization of rainwater on campus roofs.This paper takes the Lintong Campus of Xi'an University of Science and Technology as the research object,through the methods of statistical analysis,experimental research,design calculation,simulation analysis,etc.,the feasibility of its roof rainwater utilization,system composition,facility selection,initial rainwater abandonment flow and storage tank volume.Etc.The main research contents and conclusions are as follows:Firstly,the TP,COD,SS and other pollutants in the roof rainwater are analyzed.The systematic analysis of the rainfall data of Xi'an for many years shows that the rainfall characteristics are relatively concentrated in annual rainfall,especially in summer,the average annual rainfall reaches 802.1mm.In comparison with the national regulations on the use of roof rainwater resources in terms of water quality and rainfall,the results show that the water volume of roof rainwater in Xi'an meets the requirements of rainwater resources utilization,and the water quality can fully meet the water requirements of urban miscellaneous water.Moreover,the contradiction between water supply and demand in Xi'an is large,and the use of roof rainwater can alleviate the water shortage in the campus.Therefore,it is feasible and necessary to carry out the rainwater utilization of campus roofs in Xi'an.Secondly,based on the geographical environment of Lintong Campus,the roof rainwater utilization plan of the campus is analyzed.The key technologies of the roof rainwater utilization system are proposed:unit area division,roof rainwater utilization method,initial abandonment flow and volume determination of the storage tank.According to the specific building layout of Lintong Campus,the research is divided into teaching area and living area.Considering the principle of collection and utilization nearby,it is divided into four unit areas,and it is proposed that the ?,? and ? areas adopt ecological collection,and the IV area adopts rainwater pipes.The collected design schemes are mainly used for greening irrigation,flushing roads,etc.Finally,according to the initial abandonment flow theory of roof rainwater,through the simulation calculation,when the design rain intensity of Lintong Campus is 1.52mm/min,the initial abandonment time is 8.2min,the initial rainwater abandonment flow is 207m3,and the rejection rate is 70%;Select SCS rain type,carry out 24-hour rain type design for daily rainfall of 54.8mm in Xi'an in 2 years,and use SWMM software to simulate the volume of four unit area storage tanks.The research results provide a scientific basis for the utilization of roof rainwater in other similar areas. |
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