植物浮岛湿地处理太湖流域农村生活污水效果

为了探讨植物浮岛人工湿地对农村生活污水的处理效果，选用女贞、小叶女贞、红冬青和蕙兰4种陆生植物，构建植物浮岛湿地，进行农村生活污水处理试验。结果表明，在模拟自然条件下，水力停留时间为6 d，COD、氨氮、总磷和浊度的去除率分别达到60%、65%、60%和70%；而在间歇增氧条件下，可使COD、氨氮和浊度去除率提高至80%以上，水力停留时间缩短至5 d。动力学分析表明，间歇增氧植物浮岛系统中COD降解过程符合一级反应，其中，女贞的反应速率常数k为-0.591，蕙兰的反应速率常数k为-0.978。氨氮的降解符合零级反应，女贞和蕙兰对氨氮的降解速率分别为46.32 mg/d和43.76 mg/d。在间歇增氧植物浮岛湿地中，植物根系及其表面生物膜对污水中污染物的降解有较好的协同作用。示范工程1 a多连续运行表明，人工植物浮岛湿地一年四季对农村生活污水均有较好的处理效果，出水指标可达《污水综合排放标准(GB8978-1996)》一级B排放要求。该研究对于指导江南（太湖）及类似地区采用植物浮岛湿地处理农村生活污水有一定的参考价值。

Effects of rural domestic sewage treatment in Taihu Lake Valley by wetland of plant floating island

The treatment effects of rural domestic sewage were researched by wetland of plant floating island, choosed four land plants which were Ligustrum lucidum, Ligustrum quihoui Carr, Ilex purpurea Hassk and Cymbidium faberi Rolfe were chosen to make wetland of plant floating island. The results showed that the removal rates of COD, TP and NTU could reach 60%, 65%, 60% and 70%, respectively, in 6 days of retention time under natural conditions simulated. Furthermore, all the removal rates except TP could increase to 80% above and then the retention time could decrease to 5 days by aerating intermittently. The dynamic analysis indicated that the reaction of COD removal followed the first-order reaction in the system of plant floating island with intermittent aerating, and the reaction rate constant K of plants were -0.591 (Ligustrum lucidum) and -0.978 (Cymbidium faberi Rolfe). On the other hand, the degradation process of NH3-N met the zero-order reaction. The removal rates of single plant were 46.32 mg/d (Ligustrum lucidum) and 43.76 mg/d (Cymbidium faberi Rolfe). Synergistic effects of plant roots and the biomembrane of the plant surface were good for the degradation of pollutants in sewage. The demonstration project after working continuously for more than a year indicated that the wetland of plant floating island had a better purifying capacity to treat rural domestic sewage in every moment at each season of the year, the effluent water could meet Grade B discharge demands of integrated wastewater discharge standard (GB8978-1996). The study could guide valuably some regions which were analogous or located near south of the Yangtze River to adopt the wetland of plants floating islands to treat rural domestic sewage.