Research On The High-Ammonia Domestic Wastewater Treatment In The MBR Process

Among wastewater treatment technologies,membrane bioreactor (MBR) process is of great potential both technically and economically,especially in reuse of domestic/municipal wastewater and treatment of wastewater with high ammonium concentration.The objective of this study is to compare the effectiveness of various MBR processes on nitrogen removal from high ammonium wastewater in order to find out the optimal one.This paper conducted on the experiment using integrated MBR and SBR+MBR for treating domestic wastewater.It mainly studied two bio-membrane reactors about the feasibility of long-term operation,kinetics model of degradation,controlling of the optimum operation condition.The efficiencies of ammonium nitrogen(NH₄⁺-N) and total nitrogen(TN) removal of all the processes were analyzed with emphasis on the factors influencing simultaneous nitrification and denitrification(SND).The results obtained are as follows:1) During the long-term operation of two bio-membrane reactors,they went stable. Then COD,NH₄⁺-N could be removed effectively and the average removal efficiencies of them were over 93%.The removal efficiency in integrated MBR was higher than in SBR+MBR.COD and NH₄⁺-N of effluent were respectively below 10mg/L and 17mg/L. But the removal efficiency of TN in SBR+MBR could be up to 30%in stable stage.2) The interception performance of the membrane has an important influence on COD removal.The interception capacity of the membrane can reach 30～40mg/L.3) SND occurred in MBR and SBR under low DO and high MLSS.The optimum operation condition in integrated MBR was MLSS=6000～8000mg/L and DO=1.0～2.0mg/L,compared to MLSS=4000～5000mg/L and DO=1.0～2.0mg/L in SBR.4) The research of process of SND shows that NO₃^--N declined in the first 0.5 hour, but in the remaining hours NH₄⁺-N declined.The reason was that carbon was enough for denitrification in the first 0.5h.