模拟人工湿地中植物多样性配置对硝态氮去除的影响

Effect of plant diversity on nitrate removal in simulated constructed wetlands

为检验植物多样性对人工湿地脱氮功能的影响,在模拟人工湿地试验系统中设置了植物单种和混种处理并定期供给氮形态仅为硝态氮的模拟污水。结果表明:混种系统的出水硝态氮浓度显著低于单种(P<0.05);混种与单种系统在基质氮含量和植物氮积累量上无统计差异;质量平衡分析表明混种促进系统反硝化强度;菩提子单种系统中的硝态氮移除能力显著高于香蒲、芦苇和菖蒲单种系统,后3种硝态氮移除能力则无显著差异。本研究可为人工湿地选择高效物种、多样性配置以提高氮去除率提供依据。

To study the effects of plant diversity on the nitrogen removal efficiency in constructed wetland, a simulated constructed wetland with monoculture and mixed planting of four plant species was established, and nitrate was supplied periodically to simulate the sewage nitrogen inflow. In the mixed planting system, the effluent nitrate concentration was significantly lower than that in monoculture system （P0.05）, but the substrate nitrogen and plant nitrogen had no significant difference between the monoculture and mixed planting systems. The denitrification rate in the mixed planting system was higher than that in the monoculture system. The nitrogen removal efficiency in monoculture system Coix lacryma-jobi was significantly higher than that in the monoculture systems Typha angustifolia, Phragmites australis, and Acorus calamus, and no significant differences were observed between the latter three monoculture systems. This study showed that higher nitrogen removal from constructed wetlands could be achieved by mixed planting of multiple species with high nutrient removal efficiency.