Study On The Upgrading Process Design Of The Fuxian Sewage Plant In Shaanxi Province

This paper studies the actual operating efficiency of urban sewage treatment plant in Fu County, Shaanxi Province, which uses oxidation ditch process. the plant puts into operation in October 2010.In the beginning, the plant woks normally, and the effluent quality can basically reach 《 Pollutant discharge standard for urban sewage treatment plant 》(GB18918-2002) at the level of B standards. However, with the enhancement of urban sewage pipe network penetration, the influent amount of water continues to increase, and the effluent quality of water is not up to standard, especially NH3-N and TP.Through the investigation of sewage collection pipe network and analysis for the main pollutants, it is discovered that the main pipeline exists leakage. So that the concentration of major pollutants are low, and carbon source cannot meet the requirements of the subsequent biological treatment. The actual measurement value of influent water quality of SS, COD,BOD5, NH3-N and TP were: 87mg/L, 133mg/L, 61mg/L, 25.1mg/L, 2.38 mg/L; the actual measurement value of effluent water quality were: 16mg/L, 52 mg, 16mg/L, 19.3mg/L,1.08mg/L.According to the problems occurred in the actual operation of the plant, it is investigated and analysed for the structures, equipment, effluent quality and the amount of water of the plant. The reform plans are put forward..One is to maintain the original sewage collection pipeline, thus the waste-water will do not pollute the groundwater and rivers along the way;the other one is to adjust the original oxidation ditch process for biological treatment without replacement. So the effluent quality of water can meet the standards at the level of B. At the same time, it is necessary to treat secondary processing of the original water for the tertiary treatment or sewage depth processing.Comparing “biological aerated filter(BAF) reaction pool-fibre disc filter”, “coagulation sedimentation- immersed ultrafiltration” and “coagulation sedimentation- fiber disc filter”with each other, we choose the “coagulation sedimentation- fiber disc filter” as the sewage depth processing which has good effluent quality, low operation cost and less investment. Itstreated effluent can meet the standard at the level of A.