Technical Research On Bidding Improvement Of Sewage Treatment Plant In A County Of Xi'an City

With an increasing demand for environmental management in key river valleys in China,establishing an enabling environment to facilitate economic growth is a vital requirement.People's demand for environmental protection is also increasing.Since 2015,the State Council has officially released several action plans,such as“the Water Pollution Prevention and Control Action Plan”,demanding that the quality of water environment should have a periodical effect before 2020.By 2030,the quality should have a systematic improvement of the whole country,and the aquatic ecosystem should be initially restored.By the middle of this century,the aquatic ecosystem could be operated in virtuous circle^[2].In the meantime,Xi'an Government has released the action plans which require the effluent quality from the urban sewage treatment plants to meet the surface water standard IV?unit mg/L?,that is,BOD₅?6,COD_Cr?30,SS?10,NH₃?1.5,TN?12,TP?3,and the sewage treatment rate of cities and counties has to reach 98%and 85%respectively.With the background of building a greater Xi'an,the recent and long-term population growth scale of A County has exceeded the design load of infrastructure.Therefore,it is an urgent plan to upgrade the county sewage treatment plant.The theme of this paper is to study the expansion and upgrading scheme of sewage treatment plant in this county.Based on the test results,the current situation of the influent and effluent water quality was determined.The effluent water quality standard was set according to the surface water standard IV with deodorization facilities.At the present stage,the scale of the sewage treatment plant is 15 thousand m³/d and planned to expand the volume to 30 thousand m³/d.In the meantime,it would increase the standardization of current technology by providing an action plan with“preprocessing-A²/O-Membrane bioreactor-Sodium hypochlorite disinfection-Sludge Treatment of Belt Concentrator-Sludge Treatment of Plate and Frame Press Filter-Biofilter Deodorization”,to achieve the expanding of volume of the sewage treatment plant,increasing the loading parameters to above 85%.Furthermore,we analyzed the technical feasibility of the proposed upgrade scheme,and accessed its environmental impacts.The results suggest that the proposed upgrade scheme is suitable for the requirement of the objective region.Our research would be a theoretical reference for water pollution controls of A Country in Xi'an,and also be a positive response to the requirement of water environment protection.