不同植物组合对模拟污水厂尾水的净化效果及对根系微生物群落的影响

Effects of different plant combinations on purification effect of simulated wastewater treatment plant tail water and root microbial community

为阐明不同水生植物配置对污水厂尾水净化效果的影响,选取常用于生态修复中的3种挺水植物——西伯利亚鸢尾(Iris sibirica)、石菖蒲(Acorus tatarinowii)和再力花(Thalia dealbata),并将这3种挺水植物分别与粉绿狐尾藻(Myriophyllum verticillatum)进行配置,比较3种不同植物配置系统对污水厂尾水营养物的去除效果.结果显示,经过40 d的试验,狐尾藻+西伯利亚鸢尾组合对尾水中总氮、总磷和硝态氮的去除效果最佳,最高去除率分别达94.7%、96.2%和98.9%;狐尾藻+西伯利亚鸢尾组合的生物量增长率也是3个试验组当中最高的,达66.4%.高通量测序表明,3种植物组合根系微生物表现出了明显群落差异;其中,狐尾藻+西伯利亚鸢尾组合在根系微生物方面拥有最高的ACE丰富度指数;反硝化菌属和脱磷菌属相对丰度最高的植物组合是狐尾藻+石菖蒲组合,分别达到了14.19%和9.67%.上述结果表明植物的生长状况和根系脱氮除磷相关菌属的相对丰度均会对系统的净化能力产生影响,但植物的生长吸收是污水中营养盐得以去除的主要途径.(图4表5参38)

To elucidate the influence of different aquatic plant configurations on the purification effect of wastewater treatment plant tail water,an experiment was performed to evaluate the influence of different emergent aquatic plants(Myriophyllum verticillatum+Iris sibirica,M.verticillatum+Acorus tatarinowii,and M.verticillatum+Thalia dealbata)compared to the plant-free control.After 40 days,the best removal of total nitrogen,total phosphorus,and nitrate nitrogen was found using M.verticillatum+I.sibirica,with removal rates of 94.7%,96.2%,and 98.9%,respectively.The highest biomass growth rate(66.4%)was also found using this plant combination.High-throughput sequencing results showed that the root microbial community structure was different among different plant combinations.The combination of M.verticillatum and I.sibirica had the highest ACE richness index in terms of root microorganisms.The highest relative abundances of denitrifying bacteria and dephosphorizing bacteria were found using M.verticillatum+A.tatarinowii(14.19%and 9.67%,respectively).Therefore,both the growth status of plants and the relative abundance of root bacteria are responsible for nitrogen and phosphorus removal from wastewater.Furthermore,growth and absorption by plants are the main ways to remove nutrients during sewage treatment.