4种不同生活型湿地植物对富营养化水体的净化效果

选择4种湿地植物菖蒲、香蒲、浮萍和金鱼藻,研究单一及组合湿地植物对高浓度污水(污水处理厂进水)、低浓度污水(污水处理厂出水)中营养物质的去除效果.结果表明: 水体中总氮(TN)、总磷(TP)、化学需氧量(COD)浓度呈现试验前期快速下降,后期缓慢下降的趋势,表明湿地植物能有效净化污水中的TN、TP、COD,但不同湿地植物及湿地植物组合的净化效果存在差异.多种湿地植物组合比单种湿地植物对TN的净化作用强,其中香蒲＋浮萍＋金鱼藻对TN的净化效果最佳;高浓度污水中,单种挺水植物对TP的净化效果较好,低浓度污水中,则是多种湿地植物组合对TP的去除率较高;高浓度污水中,湿地植物对COD的去除率为85.1%～96.0%,其中菖蒲、香蒲去除效果最佳,低浓度污水中,湿地植物对COD去除率为76.9%～94.8%,以菖蒲＋浮萍＋金鱼藻去除效果最好.总体看来,湿地植物对高浓度污水中TN、TP、COD的净化效果好于低浓度污水,两种水体的pH都得到改善.

Purification efficiency of four different ecotypes of wetland plants on eutrophic water body

Four wetland plant species (Acorus calamus, Typha orientalis, Lemna minor, Ceratophyllum demersum) were grown to compare the purification efficiency of wetland plant species alone and in combination on two eutrophic water bodies, high concentration sewage (influent) and low concentration sewage (effluent) in a wastewater treatment plant. The results showed that the concentration of total nitrogen (TN), total phosphorus (TP) and chemical oxygen demand (COD) decreased sharply at the beginning of the test, but this decreasing trend slowed down in the late phase. The wetland plants could remove TN, TP and COD from wastewater effectively, but the degree of purification was different among different wetland plant species and among different combinations of these species. The wetland plant species were more effective in reducing TN when used in combination than used alone, and the combination of T. orientalis, L. minor and C. demersum had the highest efficiency in removing TN. The emerged plant species alone were more effective in removing TP in the high concentration sewage, but wetland plant combinations had a higher removal efficiency of TP in the low concentration sewage. In the high concentration sewage, the COD removal efficiency of wetland plants was 85.1%-96.0%, and A. calamus and T. orientalis had the highest removal efficiency. In the low concentration sewage, the COD removal efficiency of wetland plants was 76.9%-94.8%, and the highest removal efficiency was observed in the combination of A. calamus, L. minor and C. demersum. On the whole, the efficiency of wetland plants in removing TN, TP and COD was significantly greater in the high concentration sewage than in the low concentration sewage, and pH was improved in both treatments.