11种水生植物的表面流人工湿地净化污水的效果研究

Effect of Sewage Purification by Surface Flow Constructed Wetland of 11 Kinds of Aquatic Plants

通过建立表面流人工湿地系统,研究11种水生观赏植物在不同水力停留时间(HRT)为3、8、13、18 d时对COD(化学需氧量)、TN(总氮)、NH^(+)_(4)-N(氨氮)、TP(总磷)的净化效果。结果表明,11种水生植物对各污染物的去除率总体高于无植物对照(CK),其对COD、TN、NH^(+)_(4)-N、TP的平均去除率分别在78.89%~89.26%、90.49%~97.96%、93.24%~98.86%、86.52%~94.88%,水质指标均符合《地表水环境质量标准》(GB 3838-2002)。4种污染物在运行初期均呈现快速降低趋势,随HRT增加去除率达到较高水平并保持相对稳定。以旱伞草对COD的去除效果较好,菖蒲和再力花对TN、TP净化能力最佳,NH^(+)_(4)-N去除率以大薸最高,熵值法分析结果以菖蒲的综合净化效果最强,而美人蕉净化污水能力相对较低。

Through establishment of surface flow constructed wetland system,to study the purification effects of 11 aquatic ornamental plants on COD(chemical oxygen demand),TN(total nitrogen),NH^(+)_(4)-N(ammonia nitrogen)and TP(total phosphorus)under different hydraulic retention time(HRT=3,8,13,18 d).The results showed that the removal rate of each pollutant by 11 aquatic plants was generally higher than that of non-plant control.The average removal rates of COD,TN,NH^(+)_(4)-N and TP were 78.89%-89.26%,90.49%-97.96%,93.24%-98.86%and 86.52%-94.88%,respectively.The water quality indexes reached the standard of surface water environmental quality standard(GB3838-2002).The four pollutants showed a rapid decrease trend in the early stage of operation,the removal rate reached a high level with the increase of HRT and remained relatively stable.Among them,Cyperus alternifolius had better removal effect on COD,Acorus calamus and Thalia dealbata had better purification effect on TN and TP,and Pistia stratiotes had the highest purification rate of ammonia nitrogen.The results of entropy method showed that the comprehensive purification effect of A.calamus was the strongest,while the purification ability of Canna indica was relatively low.