Application Of MAO-MBR Process In The Reform Of Municipal Wastewater Standards

Water pollution is increasingly serious.Water shortage has affected the ecological environment and human health.Wastewater discharge standard is more and more strict,that improved the state of water resources comprehensively is imminent.Based on the current situation,upgrading and reconstruction of sewage treatment plants is the key technical problems in urban sewage treatment industry,needed to be solved imminently.According to the influent quality of a sewage treatment plant in Tianjin,with grade A standard of Tianjin "urban sewage treatment plant water pollutant discharge standard"(DB12599-2015)as effluent standards,the research was designed.The combination process of multilevel AO and MBR was chose to study finally.Through the pilot of experiment,debugging and optimizing test to the MAO-MBR process was to research characteristics and advantages systematically and confirm the reasonable range of parameter selection,the removal effect of contaminants and the operation situation at the low temperature.Pilot test results was as follows:at the low temperature(7-13?),after the treatment of MAO-MBR combination process,the average concentration of effluent COD,NH3-N,TN,TP is 24.45mg/L,0.85mg/L,6.00mg/L and 0.10 mg/L respectively,and the average removal rate is 97%,98%,86%and 97%respectively,achieving the A grade standard of Tianjin "urban sewage treatment plant water pollutant discharge standard"(DB12599-2015).And the system reflects the strong ability of resistance to shock loading of influent quality in a certain range.Based on HRT,DO,R,SRT and membrane pool aeration rate on the effects of combination process efficiency in the research,when the HRT was 12.5h,each pollutant treatment effect is better.DO<lmg/L,the removal rate of TN is lower.But when DO>2mg/L,the digestion of the organic matter is affected,influenced the effluent COD.At the four conditions of the sludge reflux ratio R=50%,75%,100%,75%,removal rate of TN and ammonia nitrogen increased gradually.When R=50%,effluent quality has reached the standard,indicating 50%of the reflux ratio can meet the requirements in level 4 multipoint design.The system effluent TP is affected significantly by SRT.When the SRT=12.5d,removal rate of TP is 97.8%;when the SRT>40 d,removal rate of TP decreased;when the SRT=100 d,sludge was in aging,so removal rate of COD,ammonia nitrogen,TN had decrease trend.When membrane pool aeration rate=30m3/h,the increase rate of the transmembrane pressure is 0.8 KPa/d,alleviating the membrane fouling and ensuring the TP removal rate.Through studying the path change of combination process of MAO-MBR,it showed the path concentration gradually reduce,MLSS concentration has gradient.The consumption of COD,ammonia nitrogen,TN,TP mainly occur in the first two level,bearing most of the removal.COD has a contain effect on TN.When COD>400mg/L,nitrogen removal rate can reach more than 85%.When COD is below 400mg/L,effluent TN concentration reduce,about 10mg/L.From 10? t0 18?,nitrification rate of combination process increase by 25%.Compared with biochemical part,the nitrification rate of combination process is higher,the temperature of 10?,from 0.014kgNH3-N/(kgML S S · d)increases to 0.021kgNH3-N/(kgMLSS·d).The MAO-MBR technology is a kind of sewage treatment technology,energy saving,high efficiency and stability.It can be used to upgrade the actual engineering to improve water quality.