用镶嵌组合植物群落控制湖泊饮用水源区藻类及氮污染

The purification of mosaic community of macrophytes for eutrophic lake water

依据湖泊中不同生态类型水生高等植物的微生境特点，设计建造了由漂浮、浮叶、沉水植物为优势种的斑块小群丛构成的镶嵌组合水生植物群落（ＭｏｓａｉｃＣｏｍｍｕｎｉｔｙｏｆＭａｃｒｏｐｈｙｔｅｓ：ＭＣＭ），并在太湖五里湖一湖湾内以动态模拟试验，从群落水平研究了水生高等植物群落对富营养化湖泊饮用水源区湖水的净化能力。结果表明，富营养化湖水经ＭＣＭ净化后，藻类生物量（以Ｃｈｌａ计）下降５７７％，藻类数量下降２～３个数量级，氨氮下降６６７％，总氮下降６００％，水质得到明显改善。与以该湖湾湖水为水源的水厂出水相比，经ＭＣＭ净化的湖水其氨氮比水厂出水的氨氮平均低４５１％，总氮低３７３％，可见经ＭＣＭ净化的湖水部分指标优于同源的自来水。综合群落的微生境特征及水生高等植物群落内硝化反硝化细菌分布特点，探讨了ＭＣＭ的除氮机理。

A mosaic community of macrophytes (MCM) is built with aquatic macrophytes of various ecological group in a bay of Taihu Lake. Its area is about 200 m 2 . The purification efficiency of the MCM is evaluated by simulative dynamic test. The result shows that the eutrophic water of Taihu Lake can be purified effectively as it pass through MCM. The purified water is drawn out from MCM by a pump at the pumping capacity of 42.67 m 3 /d. The removal efficiencies of MCM for algal biomass (Chla), NH + 4 N and Total N (TN) are 57.7%, 66.7% and 60.0%, respectively. Comparing with the tap water of the local water plant, the mean values of NH + 4 N and TN of the MCM effluent are low by 45.1% and 37.3%, respectively. For the effluent of MCM, the water quality is significantly better than that for the raw water (inflow) and for the tap water of the local water plant. The results demonstrate that the eutrophic lake water can indeed purify by the mosaic community of macrophytes (MCM).