Study On Drainage Planning And Sewage Treatment Process Of Airport New City

Xixian Airport New City is a newly established western transportation hub city,which plays an important role in promoting regional economic development in Shaanxi and even the whole western region.However,drainage system in Airport New City is backward,and the existing pipe network mostly adopts the combined system of rain and sewage,with imperfect facilities and low pipe network coverage.From the land use structure,it can be seen that most of the planned areas are villages and towns and farmland,and most of the sewage is discharged along with the surface runoff arbitrarily.The water bodies in the north inclined ditch and Jinghe River in the area are seriously polluted.According to the current situation of the airport new town,the rainwater collection is divided into reasonable areas and the pipe network layout is carried out.Facing different building characteristics,low-impact development facilities such as permeable pavement,green roof and high-level flower beds are designed respectively,technologies such as source interception and emission reduction and end storage are adopted to make up for the deficiencies of the traditional rainwater pipe network system,the construction of sponge city can reduce surface runoff,control pollutants,improve environmental quality,and help solve the urban waterlogging problem while recycling rainwater.In the aspect of sewage,this article has carried on the reasonable area division and the pipe network arrangement to the sewage collection,and has carried on the craft comparison analysis design to the airport north district sewage treatment plant.By analyzing the local hydrological situation,population,land nature and scale,etc.,the acceptable water quantity,inlet and outlet water quality,process flow and optimal design of the sewage treatment plant are comprehensively determined.The sewage treatment plant will be constructed in stages,with the first stage capable of treating3.0×10⁴m³of water per day and the second stage capable of treating 6.0×10⁴m³of water per day.The designed influent quality is BOD:250 mg/L;COD:450 mg/L;SS:400 mg/L;NH₃-N:35 mg/L;TN:50 mg/L;TP:7.0 mg/L.The designed effluent quality reaches the surface level IV water quality standard.Sewage treatment process adopts:coarse grid+pump room+fine grid+aerated grit chamber+three-stage AO series process+secondary sedimentation tank+high density sedimentation tank（after adding chemicals）+filter cloth filter equipment+contact disinfection canal（sodium hypochlorite）.Sludge treatment adopts:gravity concentration+digestion+mechanical dehydration+mud cake outward transportation.Deodorization process adopts:biological deodorization filter.