饮用水快速砂滤池优势微生物群落的代谢功能解析

快速砂滤池广泛应用于饮用水处理中,其净水效能一直被认为是物理化学作用,而对滤池表面附着微生物的净水作用仍不明晰.为了解析滤池中微生物的群落构成和功能特征,研究对国内8个城市的11座饮用水快滤池的进出水和滤料进行采样分析.进出水水质分析结果表明经过滤池处理,溶解性有机碳(DOC)有少量去除,氨氮(NH_4~+-N)显著降低,硝酸盐氮(NO_3~--N)显著增加,总氮(TN)未发生明显变化.利用宏基因组技术获得了滤池中微生物群落的构成和功能信息,滤池优势菌属(相对丰度占前10%)共14种,包括两类氨氧化细菌Nitrospira和Nitrosomonas.对优势菌属的功能基因信息进行分析,发现优势微生物菌群具有更高的碳水化合物、氮、硫和异生物质代谢功能丰度. Aeromonas的碳水化合物代谢基因相对丰度最高,Bradyrhizobium的氮、硫及异生物质代谢基因的相对丰度最高,说明这两种菌是影响饮用水水质的重要菌属.通过评价各个优势菌属对异生物质的代谢潜能,发现Bradyrhizobium、Sphingomonas、Methyloglobulus、Sphingopyxis和Klebsiella是饮用水快速砂滤池中降解微量有机污染物的关键菌.

Metabolic Functional Analysis of Dominant Microbial Communities in the Rapid Sand Filters for Drinking Water

Rapid sand filter (RSF) is widely used in drinking water treatment plants. Rapid filtration is always considered a physicochemical process, but the effect of the microorganisms that attach to the filter media remain inadequately investigated. In order to understand the composition and functional characteristics of microbial communities in RSFs, influent water, effluent water, and filter materials from eleven RSFs in eight Chinese cities were sampled and analyzed. After filtration, dissolved organic carbon (DOC) showed a slight but significant removal due to the growth of heterotrophic microbes. The activity of ammonia-oxidizing microbes and nitrite-oxidizing microbes promoted a significant decrease in ammonia nitrogen (NH₄⁺-N) and a significant increase in nitrate nitrogen (NO₃^--N) in water. No significant changes in total nitrogen (TN) were observed, indicating that denitrification and anammox were weak in the RSFs. The composition and function of the microbial communities of RSFs were assessed using metagenomic methods. Genera in the top 10% with respect to relative abundance (14 genera in total) were identified as the dominant genera, including the two ammonia-oxidizing bacteria Nitrospira and Nitrosomonas. Functional gene information for the dominant genera was also extracted for analysis. The dominant genera exhibited higher relative abundances of carbohydrate, nitrogen, sulfur, and xenobiotic metabolic pathways. Aeromonas had the highest relative abundance of carbohydrate metabolic genes, and Bradyrhizobium had the highest relative abundance of nitrogen, sulfur, and xenobiotics metabolic genes, indicating that these two genera play an important role in the transformation of substances in drinking water. Finally, the metabolic potential of the dominant genera on xenobiotics was evaluated, and the results showed that Bradyrhizobium, Sphingomonas, Methyloglobulus, Sphingopyxis, and Klebsiella were the key bacterial genera for the removal of micropollutants in RSFs.