曝气生物滤池处理城镇污水厂尾水的强化脱氮及微生物群落特征分析

Study on enhancing denitrification and diversity of microbial community structure in the treatment of municipal wastewater treatment plant tail water by biological aerated filter

为优化曝气生物滤池在城镇污水厂尾水深度处理条件,采用比较方法研究了曝气量、水力停留时间以及硝化液回流等参数对曝气生物滤池去除有机物及脱氮性能的影响,并通过高通量测序技术分析了曝气生物滤池填料生物膜的微生物群落结构特征。结果表明,曝气量大小是影响曝气生物滤池硝化性能的直接因素,增大曝气量有利于反应器内生物膜硝化活性的提高,但对生物反硝化活性有抑制作用:水力停留时间过长或过短均不利于生物膜保持高脱氮活性:而硝化液回流增加了反应器内微生物与污染物的接触机会和反应时间,有利于提高反应器脱氮效果。综合分析表明,当曝气量为40 L·h^(-1),水力停留时间为0.8 h时,有硝化液回流的曝气生物滤池出水水质较好,COD平均去除率约为91.8%,NH_(4)^(+)-N平均去除率约为93.1%以及TN平均去除率约为50.4%。曝气生物滤池表现出良好的有机物去除效率,并具备较高的同步硝化反硝化能力,主要归因于填料生物膜富集了大量硝化细菌如Nitrospra和Comamonadaceae等以及反硝化细菌如Pesudomonas、Truepera和Azoarcus等。

In order to optimize the condition of advanced treatment of tail water in municipal wastewater treatment plant,this paper studied the effects of aeration amount,hydraulic retention time(HRT)and nitrate liquid reflux on denitrification performance of biological aerated filters and organic matter removal.The microbial community of biofilm was analyzed by high throughput sequencing.Results showed that the amount of aeration directly affected the nitrification performance of biological aerated filters.An increase in the amount of aeration was beneficial to nitrification activity in the bioreactor,but it could also inhibit the biological denitrification activity.HRT,either too long or too short,was harmful to the activity of biofilms.Reflux of nitrification liquid increased the reaction time and contact chance between microorganisms and pollutant in the bioreactor,which was beneficial to the denitrification performance.The comprehensive analysis showed that at the aeration amount of 40 L·h^(-1) and HRT 0.8 h,the effluent of the biological aerated filter with nitrification liquid reflux presented good quality,whose removal rates of COD,NH_(4)^(+)-N and TN were 91.8%,93.1% and 50.4%,respectively.The biological aerated filter showed excellent organic removal efficiency and high simultaneous nitrification and denitrification ability,mainly contributed by the biofilm which had enriched a large number of nitrifying bacteria,such as Nitrospra and Comamonadaceae,and denitrifying bacteria,such as Pesudomonas,Truepera and Azoarcus.