Pilot Study On MPSR Treatment Of Low Temperature And Low Carbon Source Municipal Wastewater

In northern China,winter temperatures were low,and urban sewage generally ranges from4?to15?,averaging less than 10?.The conventional activated sludge method shows the problem of poor treatment effect and poor effluent quality in cold areas.The decrease of temperature has an inhibitory effect on the growth of nitrifying bacteria.The effect of denitrification and dephosphorization during the operation of winter sewage treatment plants in cold area is not good because of the decrease of temperature,resulting in that ammonia nitrogen and total nitrogen in effluent can not reach the standard.The content of organic matter in newly built urban areas of our country is low,and the water quality and water quantity change greatly,which adversely affects the follow-up treatment system.For example,the insufficient carbon source results in the decrease of nitrogen and phosphorus removal efficiency in sewage treatment.With the economic development in the north and the development of water treatment industry,it is of great significance to develop a process that is favorable for the treatment of low-temperature and low-carbon source wastewater.This experiment with a city sewage treatment plant aerated grit chamber effluent as raw water,A pilot-scale pilot study was conducted using The micro-pressure swirling reactor(MPSR),The reactor volume is96m~3,The processing scale is240m~3/d,Aeration is 30m~3/h,Sludge return flow is10m~3/h,Sludge return ratio is 100%,Hydraulic retention time 9.6h,Sludge age 15d.Investigate the MPSR removal efficiency of pollutants under low temperature and low carbon source,the performance of activated sludge,as well as the operation control problems.In order to solve the problem that the conventional water treatment technology can not meet the requirements of effluent under low temperature and low carbon source conditions and provide a reliable reference for guiding the design and operation of the northern winter sewage treatment plant.The results show that the outlet of the reactor is dissolved oxygen 1.0mg/L~1.5mg/L,MPSR central dissolved oxygen is 0~0.2mg/L.Dissolved oxygen inside the reactor showed a gradient distribution.The average water temperature during the test is 8.9?,The average water inlet C/N is6.1,Average sludge concentration 6320mg/L,Ammonia load,Total nitrogen load were23.71g/(m~3·d),76.63g/(m~3·d),Average water COD,NH4~+-N,TN,TP,The concentration of respectively 24.26,2.31,8.18,0.15mg/L,Removalrate reached respectively 82.10%,76.85%,71.21%,82.12%,The pH of the effluent is in the range of 6.70~7.09,The effluent quality has reached the first-level A standard of"Discharge Standard of Pollutants for Sewage Treatment in Cities and Towns"GB18918-2002.Through the detection of the internal microbial phase of the reactor,it was found that the sludge activity is high,and the clockworm and the unwrapping worm appear.MPSR pilot test results show that the unique structure of the reactor and aeration,making the full contact with activated sludge and microorganisms to improve the system of low-temperature low-carbon source conditions on the removal of organic matter.Through the aerobic,anoxic and anaerobic environment constructed inside the reactor,the interior of the reactor can be simultaneously nitrified and denitrified so as to achieve high efficiency nitrogen removal.Because MPSR uses a unique method of water inflow in the center and the central area is in an anaerobic area,and the reactor is not equipped with backflow of nitrification solution,the anaerobic phosphorus release process is fully carried out.The phosphorus released from the anaerobic zone is gradually removed by swirl flow To the lateral movement,part of the anaerobic phosphorus,aerobic area of phosphorus released by the reabsorption,so as to achieve good phosphorus removal effect.MPSR achieves efficient removal of organic matter and its ability of denitrification and dephosphorization under the condition of low temperature and low carbon source,which provides a reliable basis for the design and operation of the Northern Cold Area sewage treatment plant.