人工湿地污水处理系统中的植物效应与基质酶活性

为了解植物在湿地污水净化系统中的作用与机理,构建了A-B-C三级串连垂直流人工湿地系统,并选择水葱(Scirpus validus)风车草(Cyperus alternifolius)、美人蕉(Canna indica)、和芦苇(Phragmites australis)作为测试植物,进行了生活污水处理试验.结果表明,系统中有植物单元单位面积污染物的去除量均高于无植物对照单元.与对照相比,在A、B、C三级系统中由植物效应产生的CODCr去除增量分别为43.52 g/(m2·d),20.38 g/(m2·d),30.94 g/(m2·d);TN去除增量为13.14 g/(m2·d),28.61 g/(m2·d),6.97 g/(m2·d);TP去除增量为1.2 g/(m2·d),0.66 g/(m2·d),0.06 g/(m2·d).从A到C级,污水中污质浓度递减,呈现根系活力显著增强,而植物生长量、过氧化物酶含量、生长量与氮磷积累量等显著下降趋势.基质酶活性在对照单元中较低,在有植物单元中,基质酶活性明显增大并与根系活力成正相关.

Analysis of plant effect and rhizosphere enzyme activity in a constructed vertical\|flow wetland established for sewage treatment

In order to investigate the function and mechanism of the plants in constructed wetlands used for municipal sewage treatment, a pilot vertical-flow wetland consisting of three sequenced cells (A, B and C) was established using Scirpus validus, Cyperus alternifolius, Canna indica, and Phragmites australis as the testing plant species. The results obtained from the study showed that the treatment efficiency in terms of average pollutant removal per unit area was consistently higher in A, B and C cells with plants than in relevant control cells without plants. In comparison, the increased amount of pollutant removal accounted for by the plant effect in A, B and C series was, respectively, 43.52 g/(m~2 · d), 20.38 g/(m~2 · d) and 30.94 g/(m~2 · d) for COD_(Cr); 13.14 g/(m~2 · d),28.61 g/(m~2 · d) and 6.97 g/(m~2 · d) for TN; and 1.2 g/(m~2 · d),0.66 g/(m~2 · d) and 0.06 g/(m~2 · d) for TP. From cells A to C, the root activity increased while the height of plants, length of plant leaves, dry matter of plant growth increment, amount of N and P uptake and the content of peroxide enzyme all decreased significantly with the gradually decreased pollutant concentrations in the influent. The enzyme activity in the filler layers was low in the control and was significantly enhanced in the cells with plants, with a general increasing trend towards increasing root activity.