二级串联人工湿地处理农村污水的脱氮除磷研究

采用二级串联潜流式人工湿地系统对太湖地区农村生活污水进行了脱氮除磷的试验研究。结果表明，在夏季，当进水容积负荷为400L／d时，人工湿地系统对NH4^＋ -N、TN和TP的去除率分别为83％、80％和83％，相应的污染物削减量分别为4772、5463和524mg／d；在冬季，当进水容积负荷为240L／d时，人工湿地系统对NH4^＋ -N、TN和TP的去除率分别为90％、90％和94％，相应的污染物削减量分别为7751、8893和732mg／d；降低进水容积负荷可延长系统的水力停留时间，有利于保持人工湿地系统的除污效率；二级湿地采用粒径较小的填料有助于维持系统对NH4^＋ -N、TN和TP去除效果的稳定性，该工艺可有效去除太湖流域农村生活污水中的氮、磷污染物。

Study on Nitrogen and Phosphorus Removal from Rural Domestic Wastewater by Two-stage Constructed Wetland Process

Experiments of nitrogen and phosphorus removal from rural domestic wastewater in the Taihu Lake basin were carried out by the two-stage subsurface flow constructed wetland process.The results show that in summer when the influent volume loading is 400 L/d,the removals of NH+4-N,TN and TP are 83%,80% and 83% respectively.The corresponding mass of the pollutants removed are 4 772 mg/d,5 463 mg/d and 524 mg/d,respectively.In winter while the volume loading is 240 L/d,the corresponding removals are 90%,90% and 94% respectively,and the corresponding mass of pollutants removed are 7 751 mg/d,8 893 mg/d and 732 mg/d.The results suggest that HRT is the key factor influencing the removal effects of nitrogen and phosphorus,and to lower the influent volume loading can prolong HRT and help keep the removal efficiency of the process.Using the finer media in the secondary wetland is helpful to maintain stable removals of NH+4-N,TN and TP.The process can effectively remove nitrogen and phosphorus from rural domestic wastewater in the Taihu Lake basin.