Study On The Process Design For The Second Phase Construction Of Sixth Wastewater Treatment Plant In Xi’an

This paper studied the Xi’an sixth wastewater treatment plant’s second-stage design, by monitoring from the plant, sampling, analysis and consulting the first-stagedesign, then confirmed the coming water quality and quantity, chose parameters and calculated the constructions of confirmed processing program and analyzed the cost of the treatment. The main results as follows:(1)Colleted, measured and analyzed the actual inflow quantity, combined the development and drainage network in service area of sewage plant, used of the cumulative frequency analysis to confirm the size of the second phase: 10×104m3/d;(2)Colleted and analyzed the inflow quality data of the first phase, combined the date from measured in the plant, used the guaranteed rate method, confirmed theinflow quality of thesecond-stage: BOD=230mg/L, COD=470mg/L, NH4+—N=36mg/L, TN=50mg/L,TP=5.0mg/L, SS=300mg/L;(3)Considering the operation of the first stage,by comparing processing programs, confirmed the second phase of the plant adopt to improved A/A/O process+sodium hypochlorite sterilizing, and the sludge treated by promoting dewatering in plate-frame pressure filtration;(4)By calculating, comfirmed the main constructions’ s parameters and sizes of A/A/O process;(5)Made sewage treatment cost analysis on comfirm processing, and the treatment cost is 0.73 yuan of perstere.