表面流人工湿地不同植物及其组合净化污水处理厂尾水研究

为提高表面流人工湿地对低污染水的生态净化效率,对人工湿地中湿生植物的组成进行比选研究,设置8个由不同湿生植物(包括挺水、沉水和浮叶植物)组成的表面流人工湿地,比较其净化尾水氮磷效果。结果表明:挺水植物圆币草(Hydrocotyle verticillata)和大聚藻(Myriophyllum aquaticum)组合的表面流人工湿地净化尾水氮磷效果最好,其人工湿地对TN、NO-3-N和NH3-N的平均去除率分别为68.6%、62.6%和78.2%,对TP和溶解性无机磷(DIP)的平均去除率分别为64.5%和80%。浮叶植物睡莲(Nymphaea L.)人工湿地去除氮磷能力次之,TN、NO-3-N、NH3-N、TP和DIP平均去除率分别为55%、55.2%、63.3%、56.1%和64.7%,体现一定的污染物去除潜力。沉水植物苦草Vallisneria natans(Lour.)Hara]在与圆币草等共存净化尾水过程中逐渐失去优势种地位。而由黄菖蒲(Iris pseudacorus L.)和再力花(Thalia dealbata)等挺水植物构建的表面流人工湿地,虽然生物量高,但其氮磷去除效果较差,尤其是再力花人工湿地对TN、NO-3-N和NH3-N平均去除率仅在18%~36.2%之间,对TP和DIP平均去除率也分别只有41.5%和38.7%。因此,采用圆币草和大聚藻组合构建的表面流人工湿地能更有效净化污水处理厂尾水中氮磷,对TN的去除尤为高效,能有效提升尾水水质。

Research on different Plants in surface flow constructed wetlands and their combination effects on purification of tail water from sewage treatment plant

To optimize the efficiency of surface flow constructed wetlands purifying the polluted water, eight different wetland plants(including emergent, submerged and floating leaf plants)were selected to construct eight wetlands to monitor and compare their removal rates of nitrogen and phosphorus pollutants. The results showed that wetlands with emergent plants Hydrocotyle verticillata and Myriophyllum aquaticum are the most applicable to further treat tail water as they grew densely. The average removal rates of TN, NO^-₃-N and NH₃-N were 68. 6%, 62. 6% and 78. 2% respectively and the average removal rates of TP and DIP were 64. 5% and 80% respectively. Wetlands with floating leaf plants Nymphaea L. also showed a certain potential for nitrogen and phosphorus removal and the average removal rates of TN, NO^-₃-N, NH₃-N, TP and DIP were 55%, 55. 2%, 63. 3%, 56. 1% and 64. 7% respectively. Submerged plants Vallisneria natans(Lour. )Hara lost its dominant position gradually when competing with Hydrocotyle verticillata to purify the tail water. Even though emergent plants Iris pseudair L. and Thalia dealbata had large amount of biomass, the wetlands with these plants exhibited low pollutants removal ability. The pollutants removal rates of Thalia dealbata wetlands were especially low, with nitrogen removal rates only between 18% and 36. 2% and TP and DIP removal rates only about 41. 5% and 38. 7%, respectively. So it would be better to choose emergent plants such as Hydrocotyle verticillata and Myriophyllum aquaticum rather than other emergent plants when using surface flow constructed wetlands to remove nitrogenous and phosphorus pollutants in tail water from sewage treatment plant.