间歇式潜流人工湿地中COD、NH_4-N动态变化特征

COD_(Cr) AND NH_4-N DYNAMIC VARIATION CHARACTERISTICS IN BATCH SUBSURFACE FLOW CONSTRUCTED WETLAND

采用酸化、两段间歇流人工湿地处理生活污水。废水经酸化预处理后 ,COD平均去除率 30 % ,NH4 N平均去除率 13 6 3%。第 1段人工湿地为潜流 ,周期 12h ,进水 6h ,排水 6h ,水力停留时间 (HRT) 3d ,COD去除率 6 0 %～ 80 % ,最高达 88 5 6 % ;NH4 N去除率 5 0 %～ 70 %。第 2段人工湿地为下行流 ,周期 2 4h,进水 12h ,排水 12h ,HRT 1d ,COD平均去除率 5 3 2 % ;NH4 N平均去除率大于 99%。对第 1段湿地中COD、NH4 N空间变化的研究表明 ,间歇运行所产生的大气复氧对COD、NH4 N的去除具有明显的强化作用。COD的去除基本不受温度影响 ,而NH4

The system was consisted of acidification reactor and two stage batch flow constructed wetlands treating municipal wastewater.Raw sewage was treated in a pre acidification reactor with a hydraulic retention time (HRT) of 3 hours and the average removal rates of COD Cr and (NH 4 N) were about 30% and 13.63%,respectively.The first stage constructed wetland was subsurface flow.One cycle was 12 h,including 6 h feed and 6 h drain.After 3 days of HRT,COD Cr removal varied from 60% to 80%,the maximum was 88.56%;NH 4 N removal varied from 50% to 70%.The second stage constructed wetland was down flow.One cycle was 24 h,including 12 h feed and 12 h drain.After 1 day of HRT,COD Cr average removal was 53.2%;NH 4 N average removal exceeded 99%.The spatial variation of COD Cr and NH 4 N in the first stage construced wetland demonstrated that atmosphere reaeration during draining of the wetland could strengthen the removal of COD Cr and NH 4 N.The temperature had little effect on COD Cr degradation while obviously affected the removal of NH 4 N.