8种植物床人工湿地脱氮除磷的研究

分别以水葫芦、西洋芹、空心菜、水芹、混合种(黄菖蒲、千屈菜、再力花)、千屈菜、再力花、黄菖蒲等植物床构建潜流人工湿地,研究其对生活污水氮、磷的净化功能及其去除率与水力停留时间(HRT)的变化规律。结果表明,各种植物床对TN、TP的去除率随HRT的延长而增加,不同植物床的脱氮除磷效果是不同的。千屈菜植物床对TN的去除效果最好,HRT为3d时,TN去除率为56%;HRT为6d时,TN去除率达77%。再力花植物床对TP的去除效果最好,HRT为3d时,TP去除率达78%;HRT为6d时,TP去除率达96%。其他植物床也有较好的脱氮除磷效果。各种植物床处理后出水TN、TP均较低,HRT为3d时,出水TN均低于《城镇污水处理厂污染物排放标准》(GB 18918—2002)一级A标准规定的限值(15mg/L),出水TP均低于GB 18918—2002二级标准规定的限值(3mg/L);7种植物床构建的潜流人工湿地(水葫芦的数据丢失)对TN、TP的去除均满足一级反应动力学方程,且相关性显著。

Removal of nitrogen and phosphorus by eight plants of float bed constructed wetland

The float bed constructed wetlands with water hyacinth,parsley,celery,cress,mixed plants,purple loosestrife,Thalia dealbata and Iris pseudacorus as vegetation were built to study the removal of nitrogen and phosphorus from domestic waste water and the effects of hydraulic retention time(HRT) on the removal efficiencies.Results showed that the TN and TP removal efficiency were different among the eight plants;more TN and TP were removed by the eight plants at a higher HRT.Purple loosestrife was the most effective TN remover of the eight plants,the TN removal rate of purple loosestrife was 56% when operating at 3-day of HRT and the removal rate increased to 77% when operated at 6-day of HRT;Thalia dealbata removed the most TP with TP removal rate was 78% at 3-day of HRT and 96% at 6-day of HRT.Both nitrogen and phosphorus were effectively removed in all vegetated float bed wetlands;The effluent TN of the wetlands of 3-day HRT was below the grade one discharge standard A of pollutants for municipal waste water treatment plant(GB 18918-2002).Removal of TN and TP by the seven plants of constructed wetlands was consistent with the first order kinetics,and the correlation was significant.