Study On A2/O Process For Treatment Of Wastewater

In recent years emissions of industrial wastewater and mixed wastewater emissions increasedmultiply daily with the constantly development of economic level,but there are a lot of secondary sewage plants in our country whose ability of puring the complex mixed wastewater is so limited.The paper regard Tianjin Beichen District with sewage processing factory as research object,deepening research based on the featuresof mixed wastewater and process of A^2/O.And put forward the relevant retrofit scheme of the actual project,which has a great important guide meaning to the efficient processing wastewater of secondary sewage plants.The Paper based on the A²/O Purification processof sewage processing factory in Tianjin Beichen District.Taken the water from factory along drive water for laboratory small tests which have three processionsinclude training sludge,adjustable parameter run,and stable run with making sure the inner reflux ratio was 300%,the sludge reflux ratio was70%,and the sludge age was15d.Under the stable condition of the reflux ratio,days for 60days,at around 87%for COD removal stability,system impact resistance negative test is good,for TN removal is as high as 77.03%,for ammonia nitrogen removal rate can reach more than 88%which has a good nitrification performance.But system for TP removal is still cannot meet the target due to the raw water quality is not stable and the water contains high phosphorus.we analyze the details of every link of the process and deepening the research for the A²/O process.By changing several key parameters such as the C/N ratio,C/P ratio,and anoxic/aerobic volume,the removal efficiency of COD,TN,ammonia nitrogen have further ascension with system.As a result,under the situation of C/N ratio is about 7.5 and the C/P ratio is about 30,the TP removal is as high as 95.5%,which effectively enhance of TP removal efficiency.Reached the requirementsof high phosphorus mixed sewage effluent water.We can draw the following conclusions with the above test experiments,which has a practical guiding significance to the practical engineering.?1?The sludge age dose not effect COD removal.But with the extension of sludge age the anaerobic pool to improve the removal rate of COD,which extended the sludge age can make the microbes to grow better and increase the removal rate of The anaerobic pool.?2?Different Reflux ratioconstantly increasesthe removal of TN.Since higher reflux ratio in anaerobic denitrification of nitrate of quantity is more,which plays a positive role for TP reflux ratio.As for TP,the greater reflux ratio the removal effect is poorer.Because excessive nitrate exist in denitrifying bacteria and denitrifying bacteria in the competition of phosphorus accumulating dominant,which reduces the phosphorus accumulating PHB content for phosphorus removal.It is suitable to take the sludge reflux ratio at 70%,nitrifying liquid reflux at 300%with considering the energy consumption and operating costs,in the actual engineering?3?In the operation of the actual engineering,C/N ratio and C/P ratio control are more important,especially high phosphorus wastewater?We need to fine adjust the C/P ratios therefore reached efficient removal of TP.This experiment adjusts the C/P at around 30which can achieve efficient removal.