Multi-stage A/O-MBR Process For The Removal Of Nitrogen And Phosphorus From Domestic Sewage

With the continuous advancement of urban construction in China,the level of economic development has gradually improved,accompanied by the rapid development of urbanization,The amount of urban sewage has also gradually increased,seriously polluting the urban environment,so how to manage urban sewage has become an urgent problem that needs to be solved urgently in urban development.In response to the current status of urban sewage treatment in China,the urban water treatment wastewater treatment plant will be upgraded,which puts higher and higher requirements on water treatment technology and technology.This experiment is mainly aimed at the problem that the traditional A2/O process is difficult to achieve high-efficiency nitrogen and phosphorus removal from domestic sewage.The influence of water inflow mode and reaction series on nitrogen and phosphorus removal in multi-stage and multi-stage A/O-MBR process is discussed.Changes in sludge load and contaminant removal in each bio unit.The test was carried out at a sewage treatment plant in Tianjin.On the basis of the traditional A2/O process,a membrane bioreactor was added to the urban sewage treatment problem,and a sedimentation tank was added between the biochemical pool and the membrane pool to design and construct a multi-stage.The multi-stage A/O-MBR process pilot test equipment was used to analyze the influence of the reaction number and water inflow mode of the multi-stage multi-stage A/O-MBR process system on nitrogen and phosphorus removal of domestic sewage.Results:The system uses a three-stage Aoi process with a single point of water in the anaerobic zone,a four-stage A/O process with 50%,22.70%,18.30%and 9%water intake,and 55%,a three-stage A/O process with 55%,30%and 15%water intake.The experimental results show that when the average concentrations of influent COD,TN,NH3-N and TP are 258.31 mg/L,27.50 mg/L,17.20 mg/L and 2.77 mg/L,respectively,the three-stage A/O process system with 55%,30%and 15%water inflow has the best water treatment effect,the average concentrations of COD,NH3-N,TN and TP in the effluent were 21.20 mg/L,0.48 mg/L,4.11 mg/L and 0.51 mg/L,and the average removal rates were 90.26%,96.88%,81.88%and 76.45%.The effluent COD and NH3-N concentrations all reached the Class IV water standard of Surface Water Environmental Quality Standard(GB3838-2002),and the effluent TN concentration reached the Grade A standard of“Urban Sewage Treatment Pollutant Standard”(GB18919-2002).64.29%of the effluent TP reached the first-class A standard,64.29%of the effluent TP reached the first-class A standard,and the distribution of COD,NH3-N,TN and TP of each functional unit was reasonable,and the carbon source was rationally utilized.The multi-point influent three-stage A/O-MBR process ach ieves efficient use of carbon sources in sewage and low er water treatment costs.Membrane fouling is an inevitable problem of the MBR system.The test system uses various methods to solve the membrane fouling,including the construction of the inclined tube sedimentation tank in the middle of the A/O pool and the membrane pool,and the A/O pool effluent entering the inclined tube sedimentation tank;For real-time monitoring of the membrane module’s transmembrane pressure difference,the membrane module is periodically physically cleaned,and the membrane module is chemically c leaned according to the transmembrane pressure difference;An aeration device is installed under the membrane module,and the membrane fouling and the shearing force on the membrane surface are promoted by aeration to agitate the membrane filament and accelerate the flow of the mixture in the membrane pool to reduce membrane fouling and reduce cost.