Nutrient Removal Performance In The Anaerobic/Anoxic/Microoxic/Oxic Membrane Bioreactor

The wastewater effluent standards have been continuously controlled more strictly with the severe eutrophication issues have become increasingly prominent. Therefore,the wastewater treatment technology developed gradually from the single stage of COD_crremoval to the stage not only of CODcr removal,but also the deep treatment of nitrogen and phosphorus removal.The nitrogen and phosphorus removal technology for the purpose of eutrophication control has been the research focus in the wastewater treatment domain.This paper is in the view of the low carbon source sanitary sewage,focus on nitrogen and phosphorus removal performance in the Anaerobic/Anoxic/Microoxic/ Oxic membrane bioreactor to conduct the research,in which inspected the hydraulic retention time(HRT),sludge retention time(SRT),recirculation,infiuent C/N,and other factors on the membrane bioreactor performance of nitrogen and phosphorus removal.The results are as follows:(1)The system of high concentration sludge was not only strengthening the nitrification,but also existing the denitrification of phosphorus removal,nitrification simultaneous with denitrification and short-cut nitrification and denitrification processes.(2)System COD_cr,TN,TP in the influent was 260～300,46～48,7～8mg/L.Under such a low C/N(C/N=5～6),its effluent COD_cr,NH₄⁺-N maintained below 50,0.5 mg/L; the removal of TN,TP reached 80 percent,95 percent and above,with good nitrogen and phosphorus removal effect.(3)HRT,SRT,R,C/N ratio on the removal of CODcr,TP and nitrification did not have a big impact of the system,and mainly focused on denitrification effect.(4)HRT raised to the 8 h from 4 h,TN removal system have the original 60%to 75%,but further raised to 3 h,the increase in nitrogen and effect has not appeared but slight downward trend.Influent C/N ratio from 5 to 6 upgrade to 7.5,the effluent removal of former TN Some 80 percent increase to 87.5%,the effect is obvious.(5)There was no significant effect of the impact of SRT,recirculation,and other factors on the denitrification system,just only a change in the distribution of the effluent TN form and the performance of the tank.(6)The concentration of PO₄-P in anaerobic tank was 30～60 mg/L,which might be reused by chemical process.