厌氧—3级好氧/缺氧生物膜工艺处理农村生活污水

对自流式厌氧—3级好氧/缺氧生物膜工艺处理低碳氮比农村生活污水的效能进行了应用研究。装置的处理量为18 m3/d,HRT为2.9 d,厌氧段的水力负荷为0.514 m3/(m3.d),生物球装填率为15%;3级好氧/缺氧生物膜段的水力负荷为1.029 m3/(m3.d),YDT弹性填料的装填率依次为50%、40%和25%,采用跌水充氧。连续8个月的监测结果表明:该工艺对COD、BOD5、NH3-N、TN和TP的去除率分别为73.7%、76.5%、90.7%、59.6%和69.7%;出水COD、BOD5、NH3-N、TN、TP、SS的平均浓度分别在34、15、2、7.7、0.9、5.2 mg/L以下,粪大肠菌群平均为5 200个/L,可用于农业灌溉和观赏性景观河道用水。该工艺的3级好氧/缺氧生物膜段能够同步进行硝化与反硝化除磷,适合于低碳氮比农村生活污水的处理。

Combined Process of Anaerobic Treatment and Three-stage Aerobic/Anoxic Biofilm for Treatment of Rural Domestic Sewage

The combined process of anaerobic treatment and three-stage aerobic/anoxic biofilm was used to treat rural domestic sewage with low C/N ratio. The treatment capacity is 18 m~3/d, and HRT is 2.9 d.At the anaerobic stage, the hydraulic loading is 0.514 m~3/(m~3·d), and the packing ratio of bioballs is 15%. At the three-stage aerobic/anoxic biofilm stage, the hydraulic loading is 1.029 m~3/(m~3·d), the packing ratios of elastic filler are 50%, 40% and 25%, and the drop-aeration mode is used. The results after eight-month operation show that the removal rates of COD, BOD_5, NH3-N, TN and TP are 73.7%, 76.5%, 90.7%, 59.6% and 69.7%, their average effluent concentrations are less than 34 mg/L, 15 mg/L, 2 mg/L, 7.7 mg/L and 0.9 mg/L respectively, and the effluent SS is less than 5.2 mg/L. The fecal coliform count is 5 200 CFU/L. The treated effluent can be used for agricultural irrigation and ornamental landscape. With simultaneous nitrification and denitrification phosphorus removal at the three-stage aerobic/anoxic biofilm stage, the combined process is suitable for treating rural domestic sewage with low C/N ratio.