Comprehensive Sewage Treatment Plant Transformation Techinques Mentioned Standard Practice

Sewage treatment plant of Xiao Shan east district passed the finalacceptance of construction and put into operation formally in August2006.The plant treated300,000m3wastewater daily, using biological absorption-anaerobic hydrolysis-aerobic treatment-clarifiers secondary biologicaltreatment processes. With the development of social and economic ofXiaoshan and the changing components of the wastewater made the systemout of condition. There is a great disparity between the current system andthe design. At the same time, with the standard getting higher, the currentwater quality of effluent can’t meet the secondary class of DischargeStandard of Pollutants for Municipal Wastewater Treatment Plant(GB18918-2002). Process improvement is imperative.Considering all above, combining with historical data of the system,the current problems of the process were analyzed. The suitable scenariofor the process improvement was selected and verified by pilot testing.Pilot testing include four mainly stage: the commissioning ofinstruments, the sludge culture, the determination of the relatively suitableconditions to the process, testing under relatively suitable conditions. Thenfive detection indexes(CODCr, BOD5, SS, TP, NH3-N) of the effluent underdesigned was analysed to verify whether the selected parameters (sludgereturn ratio, sludge age, hydraulic retention time, etc) is appropriate, to verify whether the water quality of effluent can meet the secondary class ofGB18918-2002, to verify the designed process improvement is suit for theplant, to provide basis for further upgrading and improving of the scenario.The process improvement project was started in September2009andcompleted and put into operation in December. After one year’s operation,the current water qualityof effluent can meet the requirement of the processimprovement and the secondary class of Discharge Standard of Pollutantsfor Municipal Wastewater Treatment Plant(GB18918—2002).