A study was conducted to investigate the removal efficiency of nitrogen in an Anoxic/Oxic-Membrane Bioreactor (A/ O-MBH) at different sludge residence time (10, 30, 60 days) using synthetic wastewater. Result showed that sludge residence time (SRT) had no obvious influences on the removal of chemical oxygen demand and NH+4-N. The average removal rales of chemical oxygen demand and NH+4-N were 95.4% and 98.0% , and the concentrations of chemical oxygen demand and NH4-N in the effluent were under 15 mg/L and 1 mg/L, respectively. There were significantly different accumulations of NO-2 -N in the anaerobic reactor, and the concentration reduced with the extended SRT. The accumulation of NO-2-N at SRT of 10-day was the highest, followed by SRT of 30-day and 60-day. The NO-3-N concentration of the supernatant liquor in the aerobic bank was lower at SRT of 10-day and 60-day, which would be in favor of the removal of total nitrogen. The average removal rates of total nitrogen were 66.2% , 57.2% and 67.7% for SRT of 10-day, 30-day and 60-day, respectively. The total nitrogen concentrations in the effluent were under 20 mg/L. Results suggested that the pollutant removal efficiency in wastewater was higher at SRT of 10-day and 60-day, but longer SRT could reduce the production and discharge of excess activated sludge. From an economic point of view, 60d is an appropriate SRT.%采用缺氧/好氧膜生物反应器(A/O-MBR)工艺处理模拟生活污水,考察了不同污泥停留时间t.(10、30、60 d)下反应器的脱氮效能.在A/O-MBR工艺中,tsr对化学需氧量和NH+4-N的去除效果无显著影响,化学需氧量平均去除率在95.4％以上,NH+4-N去除率在98.0％以上,出水化学需氧量与NH+4-N质量浓度均在15mg/L和1mg/L以下；缺氧段出现了明显不同的NO-2-N积累,积累量随tsr的延长而减弱,即顺序为tsr10d＞tsr30d＞tsr60d；好氧段上清液中NO-3-N的质量浓度在tsr,为10d和60 d时较低,有利于系统获得较高的总氮去除率；总氮的平均去除率在tsr为10、30、60 d时分别为66.2％、57.2％和67.7％,出水口总氯均在20 mg/L以下.试验结果表明:A/O-MBR在tsr为10、60 d时对污染物的去除均取得了较好的效果,但较长的tsr可以减少剩余污泥的产生及排放.从经济角度来讲,tsr为60d可为最佳污泥龄.
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