土著反硝化菌对巢湖流域稻田泥土脱氮效果的影响

Effect of inoculated indigenous denitrifying bacteria on nitrogen removal in paddy soil in Chaohu Lake basin

生物修复技术削减途经土壤中的硝态氮是一种环境友好且生态效益高的方法。构建了含不同填料的A(土壤)、B(土壤+木屑)、C(土壤+木屑+蜡样芽孢杆菌)、D(土壤+木屑+土著反硝化菌)4种渗透反应柱,将从土壤填料中筛选出单株具有良好反硝化性能的土著反硝化菌(Pseudomonas sp.P10)和来源于湖泊底泥的反硝化菌蜡样芽孢杆菌分别接种至渗透反应柱,探究土著反硝化菌对巢湖流域同源水稻田土壤填充渗透反应柱脱氮效果的影响。结果表明,向反应柱中接种土著反硝化菌Pseudomonas sp.P10可缩短反应柱去除NO_(3)^(-)-N的启动时间,填料为土壤与木屑的B柱对NO_(3)^(-)-N去除率可达96.05%。接种土著反硝化菌的D柱出现了NH_(4)^(+)-N积累现象,B、C、D柱中积累的[NO_(2)^(-)-N]均低于2.4 mg·L^(-1)。在30 mg·L^(-1)和50 mg·L^(-1)的NO_(3)^(-)-N进水条件下,各反应柱对TN去除率为50%~70%。各反应柱出水TOC符合水质标准。接种土著反硝化菌的D柱中优势菌种为Pseudomonas属细菌,C柱中接种的蜡样芽孢杆菌并没能成功地与原有微生物群落竞争。接种土著反硝化菌对土壤反硝化能力有一定强化作用,但随着时间的延长,在充足可利用碳源条件下,没有接种微生物的反应柱更具有反硝化脱氮优势。该研究结果可为提升土壤对外源氮素的削减和湖泊氮素污染的控制提供参考,也为湖库淤积物的资源化利用及治污情况下生态系统的稳态维持和可持续的系统动力学提供依据。

The attenuation of nitrate in soil by bioremediation is an environmentally friendly and eco-efficient method.In this study,four reaction columns including A(soil),B(soil+sawdust),C(soil+sawdust+Bacillus cereus)and D(soil+Sawdust+indigenous denitrifying bacteria)were constructed,and the indigenous denitrifying bacteria(Pseudomonas sp.P10)isolated from the soil fillers and the denitrifying bacteria Bacillus cereus from lake sediment were inoculated into the columns,aiming at investigating the effect of indigenous denitrifying bacteria on nitrogen removal in the columns filled mainly with the same paddy soil.The results showed that inoculating Pseudomonas sp.P10 into the reaction column could shorten the start-up time of NO_(3)^(-)-N removal.The removal rate of NO_(3)^(-)-N in the column B was up to 96.05%.NH_(4)^(+)-N accumulation appeared in the column D inoculated with indigenous denitrifying bacteria.NO_(2)^(-)-N accumulated in columns B,C,D was lower than 2.4 mg·L^(-1).Under the condition of 30 mg/L and 50 mg/L NO_(3)^(-)-N in influent,the TN removal rate of each reaction column was between 50%~70%.The TOC concentration in all effluents meets the water quality standard.The dominant bacteria in column D inoculated with indigenous denitrifying bacteria were Pseudomonas,while the dominant bacteria in column C inoculated with Bacillus cereus failed to compete with the original microbial community.Inoculation of indigenous denitrifying bacteria could enhance the denitrification ability of soil to a certain extent.Under the condition of sufficient available carbon source,the reaction column without inoculating microorganism has the advantage of denitrification.The results can provide more powerful clues for enhancing the attenuation of exogenous nitrogen in soil and lake,in addtion to more information for the resource utilization of lake sediment and the steady-state maintenance and sustainable system dynamics of ecosystem during pollution control.