水源切换对水厂出水细菌群落的影响

针对水源切换可能造成水厂出水微生物风险的问题,以北京某水厂由本地水源切换为河北水源期间原水和出厂水为研究对象,采用焦磷酸测序技术对水中的微生物种群结构和潜在致病菌进行分析.结果显示,出厂水的细菌多样性显著低于原水,原水和出厂水中的优势菌均为变形菌门(Proteobacteria),所占比例为11.99%~95.48%,其中包括α,β和γ变形菌纲(α, β, γ-Proteobacteria),但相对丰度有较大差异.水源切换后的原水中优势菌为蓝藻门(Cyanobacteria),且该菌在切换后的出厂水中也存在.出厂水中检测到部分潜在致病菌,优势菌包括不动杆菌(Acinetobacter)和代尔夫特菌(Delftia),增加了饮用水的微生物安全风险.PCoA结果显示,水源切换前后原水中细菌群落结构变化较大,但改变水源对出厂水的微生物群落影响较小,水厂能够维持稳定的运行.

Effect of water switch on the bacterial community structure of finished water in a drinking water treatment plant

To evaluate the microbial safety during the source water switch in a drinking water treatment plant in Beijing, bacterial community compositions and potential pathogensin the raw water and finished water were analyzed by pyrosequencing. The bacterial diversity of finished water was significantly lower than raw water. Proteobacteria were observed as one of the most dominant populations both in raw water and finished water, ranging from 11.99% to 95.48%. Alphaproteobacteria, Betaproteobacteria and Gammaproteobacteria dominated in this group. However, the relative abundance varied in raw water and finished water. Cyanobacteria were found in raw water and finished water after water switch. Several potential pathogens were detected in the finished water and the majorbacteria were Acinetobacterand Delftia. The occurrence of pathogens was associated with increased health risk. PCoA results showed that bacterial community structure in raw water before switch was significantly different from that after water switch, but water switch had little effect on the bacterial composition of finished water. The water treatment plant operated stably during water switch.