Practical Research On Upgrading And Reconstruction Of Municipal Sewage Treatment Plant In Northwest China

The paper mainly studies post-modification process and operation status of wastewater treatment plant in northwestern China.This plant original design discharge water quality is the first-class B standard in the discharge standard of pollutants for municipal wastewater treatment plant（GB18918-2002）,which not cannot meet the current national environmental protection requirements.Therefore,it is necessary to post-modification process and operation status of the original treatment process of the sewage plant.This paper analyzes the current problems such as wastewater treatment,wastewater quality,wastewater process,equipment and operation of the wastewater treatment plant.According to the principle of engineering combined with the actual situation and weigh all factors,we combining with the current large environment,including economic conditions,sewage plant management level,overall layout,environmental characteristics and other comprehensive consideration of the principle of selection,to determine the maximum status of the use of resources,mature and reliable technology,high degree of automation of information,the transformation of sewage plant is still operating,the future leave space and other transformation principles.According to the actual situation,this paper makes a comparative analysis of the optional process scheme,weighs all the factors,and determines the requirement that the first and second degree of stability should be met in the actual operation,and the third and fourth safety requirements should be satisfied,after the comprehensive analysis,it is recommended to adopt the main process as follows:After the treatment of sewage level,the A²/O biological denitrification and phosphorus removal process,drainage in the middle of the incoming and outbound radial flow sedimentation tank after precipitation into the biological aerated filter further treatment.The removal of nitrogen and phosphorus in the retrofit of urban sewage plant is a difficult problem.ompare and analyze the optional process plan,and determine the final upgrade process plan.In this plan,the A²/O pool body is used as a secondary treatment process,and the aeration biological filter is used as a tertiary treatment process.At the same time,in order to protect the influence of the external climate on the filter and the phenomenon of poor water distribution caused by freezing on the surface of the pool body in winter,A stainless steel frame is added to the building to lay a transparent sun plate cover to ensure the stable and reliable operation of the biological filter.This upgrading and reconstruction mainly uses the current situation of the sewage plant has been built facilities,the upgrading of some of the existing construction objects,including the upgrading of construction items:integrated office housing,thick grille and lifting pumping room,high-density concentrated sedimentation tank,aeration biological filter,blower room and transformer and distribution room,recoil and waste water recovery tank,sludge dewatering room,machine repair room.The newly constructed building has adjustable one of A²O biochemical pool,two of secondary sedimentation tank,one of sludge backflow infrastructant,one of deodorization room,respectively.After the completion of the upgrade and reform,the result shown that average concentrations of COD,NH₃-N,TN,TP and SS in the effluent were 25.19mg/L,0.67mg/L,9.94mg/L,0.35mg/L,7.82mg/L,respectively.All effluent water quality can meet the first-class A standard in the discharge standard of pollutants for municipal wastewater treatment plant（GB18918-2002）.The effluent can be used for recycle water,effectively alleviating the shortage of local water resources.By comparing the water discharge index of the original water plant with that of the modified plant,the COD,NH₃-N,TN,TP and SS removal rate increased by 56%,92%,78%,89%,54%,respectively.The effluent water quality has been significantly improved,in line with the regulations of the environmental protection department.Through the research of this project,The sewage treatment plant has effectively improved the local water environment quality and promoted the sustainable development of the local economy.Meanwhile,the research of this project can provide a certain technical reference for the construction of the follow-up urban sewage treatment plant,especially for the upgrading of township wastewater treatment plants in northwestern China.In addition,this modification is characterized by low work amount,low cost and full use of previous structures,so as to provide reference for upgrading of similar sewage plants.