Microbial Structure and Function of Activated Sludge in Landfill Leachate Treatment Plant

ZHANG Xue, QIAO Xuejiao, SU Jia, ZHANG Liyu, YU Ke†

Abstract 16S RRNA gene and metagenomic sequencing was applied to study the structure of microbial community, functional microorganisms and genes in activated sludge of landfill leachate treatment. The results showed that Calditrichaeota was the most abundant phylum (58.77%), followed by Proteobacteria (16.80%) and Bacteroides (6.19%). Calrithrix was the dominant genus of the activated sludge (58.77%). Five nitrogen cycle pathways were detected to form the microbial community of activated sludge, including nitrification, denitrification, assimilation nitrate reduction, dissimilation nitrate reduction and nitrogen fixation. Denitrification genes were the most abundant among nitrogen cycling process (78.84%), which mainly distributed in Calditrichaeota, Proteobacteria and Choroflexi. Nitrification was achieved by ammonia oxidizing bacteria Nitrosomonas. There were abundant organic pollutants degradation genes in activated sludge. Proteobacteria, Bacteroides, Planctomycetes, Calditrichaeota and Choroflexi were typical functional microorganisms that can degrade organic pollutants. Key words landfill leachate; activate sludge; microbial structure; function genes

垃圾渗滤液(landfill leachate)是在垃圾填埋过程中因雨水径流和厌氧降解等综合因素产生的高浓度有机废水[1], 其氨氮含量高, 有机污染物种类繁多, 不仅含有简单的烷烃、烯烃、酚类和酯类, 而且含有复杂的卤代烃、酰胺类、多环芳烃和杂环芳

烃等化合物[2]。未经处理或处理不当的垃圾渗滤液,一旦进入河流、农田和地下水等自然生态系统, 将严重污染生态环境, 对水生生物造成慢性和积累性的毒性, 对人类健康造成潜在威胁[3–5]。

目前, 垃圾渗滤液的处理方法分为物理方法、