Investigation And Research On The Technology Of Small And Medium Sized Sewage Treatment Plants In Zhejiang Province

With the increasingly serious water pollution,the removal of pollutants in the water has been highly valued.The current representative sewage treatment methods are oxidation ditch,A²/O,SBR and MBR technology.There are still some problems need to improve with these technologies in the actual operation of the process.In order to understand the status of Zhejiang province small and medium sized sewage treatment plant,this paper takes several typical small and medium sized sewage treatment plant in Zhejiang province?biochemical stage respectively by oxidation ditch,A²/O,and SBR series,MBR process?as object,do research on effects on the sewage treatment plant effluent quality of different biochemical process,according to the design specification,research the design parameters,operation parameters and removal efficiency,provides the basis and reference for design discharge,engineering design and engineering.This study adopts several ways,including actual research?test and consulting design specification,to do investigation on the city sewage treatment plant of Huzhou City,Luxi sewage treatment plant of Jiangshan City,city sewage treatment plant of Hangzhou and Tongxiang,rural sewage treatment plant of Huzhou,sewage treatment plant of Shaoxing.Huzhou north city sewage treatment plant of oxidation ditch process can achieve the?urban sewage treatment plant pollutant discharge standard??GB18918-2002?of A standard level,its removal rate of TN is about 39%,removal efficiency of the effluent NH₄-N is 99.9%,the removal rate of COD_Cr is about 45.5%.With the adoption of A²/O technology,Hangzhou west city sewage treatment plant and Tongxiang city sewage treatment plant place the anaerobic period in the first stage,effectively exploit the advantages of anaerobic bacteria can withstand high concentration and high organic loading capacity to full.It has good treatment effect and produces less sludge than general biological method.Under the condition of anaerobic,anoxic and aerobic alternating operation,the A²/O process could not proliferate in a large amount of filamentous bacteria,and the SVI value is less than100.Adopting CASS process,the effluent quality of Huzhou Bilang wastewater treatment plant reached the?urban sewage treatment plant pollutant discharge standard??GB18918-2002?of A standard level.The effluent COD_Cr is less than20mg/L,TN is less than 12mg/L,and TP is less than 0.29mg/L.The MLSS of the plant is low,mainly because the plant influent pollutant concentration is low,SVI is on the high side.The reflux ratio of sludge in the first stage was 78%,and the reflux ratio in the second stage was 72%.The Shaoxing sewage treatment plant which using MBR technology combined A²/O biochemical treatment,the effluent quality can achieve the?urban sewage treatment plant pollutant discharge standard??GB 18918-2002?of A standard level,even reaches?city sewage recycling landscape water standard??GB/T 18921-2002?.The factory in superfine grille sets up two sets of washing equipment.Membrane cleaning is divided into maintenance cleaning and chemical cleaning,when the maintenance of cleaning cannot meet the requirements of membrane flux must be used chemical cleaning,the temperature is lower when the need for greater maintenance of the frequency of cleaning.There are advantages,disadvantages and applicable conditions of the above processes.Basically all the processes are mature process,the design should be based on different areas of water quality and management habits,select the appropriate biochemical treatment process.