Xincheng Sewage Treatment Plant Upgrading And Renovation Project

With the rapid economic development and the acceleration of the urbanization process,water environmental pollution is becoming more and more serious,especially the eutrophication pollution of water bodies,which is currently one of the most difficult environmental problems faced by mankind.In order to protect the water environment and prevent and control the eutrophication of water bodies,China and other countries in the world strictly control the discharge of pollutants and raise the discharge standards of sewage,especially the discharge standards of nitrogen and phosphorus.Under the severe situation of raising sewage standards,Chinese wastewater treatment plants are facing serious challenges,especially for old plants,upgrading and transformation is imperative.This paper conducts a systematic study on the upgrading and renovation project of the Xincheng wastewater treatment plant in Tongshan District.First,systematically study the status quo of the Xincheng wastewater treatment plant,analyze its main problems,and then propose the upgrading and transformation plan of the wastewater treatment plant on this basis,and conduct demonstration and simulation experiments to determine the optimal transformation process,and finally The operation effect of the retrofit project after implementation is evaluated.The main work completed and the main conclusions obtained are as follows:(1)Before the upgrading of Xincheng wastewater treatment plant,the traditional A~2/O process was adopted,and the overall operation was in good condition.The effluent basically reached the design standard at that time,but the process was not efficient in nitrogen and phosphorus removal.When the discharge standard of tail water was upgraded from the original Class A standard to the surface level Class IV standard,The main problem is that the tailwater SS,TN and TP can not meet the standard,therefore,the focus of upgrading is to improve the SS,TN and TP removal capacity of the Xincheng wastewater treatment plant.(2)According to the main problems to be solved in the bid raising of the Xincheng wastewater treatment plant,the improvement of the combination of strengthening the original biochemical section's nitrogen and phosphorus removal effect(reconstructing and expanding the A~2/O pool and optimizing the process parameters)and increasing the advanced treatment process are proposed.Modification plan to ensure that the tail water SS,TN and TP can meet the new discharge standards:SS?5mg/L,TN?10mg/L,TP?0.3mg/L.(3)According to the A~2/O pond reconstruction and expansion plan,involving processing pilot test equipment,the effect of nitrogen and phosphorus removal of the A~2/O pond to be rebuilt and expanded was investigated through experimental research,and the operating parameters were optimized.The results show that by rebuilding and expanding the A~2/O pool and optimizing operating parameters,the denitrification and phosphorus removal effect of the biochemical section can be significantly improved.Under the determined optimal operating conditions,that is,the sludge reflux ratio r=60%,and the mixed liquid reflux ratio R=300%,C/N=5,and sludge age SRT=12,the removal rates of TN and TP reached 58.08%and 86.60%,respectively,an increase of 4.26%and 5.49%,Therefore,it is feasible to improve the nitrogen and phosphorus removal efficiency through the reconstruction and expansion of the original A~2/O tank.(4)On the basis of using the original A~2/O process to remove nitrogen and phosphorus as much as possible,an advanced treatment process is added to further strengthen the removal of SS,TN and TP to ensure that the drainage reaches the new standard.Through technical and economic comparison and demonstration,the advanced treatment process of coagulation sedimentation+denitrification deep-bed filter was determined.The final standard upgrade and transformation process for Xincheng wastewater treatment plant is as follows:water intake?primary sewage treatment system?A~2/O tanks reconstructed and expanded?coagulation sedimentation tank?denitrification deep bed filter?discharge up to standard.(5)Through the implementation of the upgrading project,the effluent quality of the Xincheng wastewater treatment plant has been significantly improved,which can stably meet the surface level IV standards.In the first year of operation,that is,the average concentration of effluent COD,SS,TN,TP,and ammonia nitrogen in 2020will be changed from the previous 20.61mg/L,5.75mg/L,14.57mg/L,0.39mg/L,1.16mg/L dropped to 12.13,mg/L,0.72mg/L,8.25mg/L,0.26mg/L,0.53mg/L,and the average removal rate increased from 82%,91%,53%,81%,95%to 90%,96%,72%,94%,97%;the average reduction was 8.48mg/L,2.96mg/L,8.25mg/L,0.26mg/L,0.63mg/L,respectively.