微塑料暴露下有/无植物人工湿地脱氮性能的对比

Comparison of nitrogen removal performance of constructed wetlands with/without plants under exposure of microplastics

为揭示湿地植物对微塑料暴露湿地脱氮性能的影响,构建了2组垂直流人工湿地(黄菖蒲湿地和无植物湿地),对比了聚苯乙烯微塑料(PS MPs)短期和长期暴露下2组湿地植物和微生物生态效应及脱氮性能的差异.结果表明,2组湿地均可实现PS MPs的有效去除,去除率均超过99.8%;PS MPs短期暴露下,黄菖蒲湿地体现出更高的脱氮性能;而PS MPs的长期暴露对黄菖蒲光系统和抗氧化系统将产生不利影响,叶片光合色素质量分数下降了13.92%~26.15%;PS MPs短期及长期暴露下,黄菖蒲湿地中微生物物种丰富度和多样性更高,硝化细菌和反硝化细菌的整体丰度也高于无植物湿地.以上结果为同步去除污水中氮素和微塑料的人工湿地设计提供了参考.

In order to reveal the effects of wetland plants on the nitrogen removal performance of microplastics exposed wetlands,two vertical flow constructed wetlands(Iris pseudacorus wetland and unplanted wetland)were established,and the ecological effects of plants and microbes and the nitrogen removal efficiencies in two wetlands under short-term and long-term exposure to polystyrene microplastics(PS MPs)were compared.The results show that both wetlands can effectively remove PS MPs,with the removal rate exceeding 99.8%;Iris pseudacorus wetland shows higher nitrogen removal performance under short-term exposure to PS MPs;while long-term exposure to PS MPs has adverse effects on photosystem and antioxidant system of Iris pseudacorus,and photosynthetic pigment mass fraction in leaves decreases by 13.92%to 26.15%;under short-term and long-term exposure to PS MPs,microbial species richness and diversity are higher in Iris pseudacorus wetland than that in unplanted wetland,and the overall abundance of nitrifying bacteria and denitrifying bacteria are higher in Iris pseudacorus wetland than that in unplanted wetland.The above results provide a valuable reference for the design of constructed wetlands for simultaneous removal of nitrogen and microplastics from wastewater.