Institute of Environmental Research at Greater Bay, Key Laboratory for Water Quality and Conservation of the Pearl River Delta, Ministry of Education, Guangzhou University, Guangzhou, 510006, China.
Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China.
Chemosphere. 2021 Jul;275:130032. doi: 10.1016/j.chemosphere.2021.130032. Epub 2021 Feb 24.
The effects of trace phosphate concentrations (0, 0.3 and 0.6 mg/L) in water source were investigated on microbial stability of the drinking water distribution systems (DWDSs). Obviously, the results verified that in the effluent of DWDSs simulated by annular reactors (ARs), the total microbial biomass and the absolute concentration of opportunistic pathogens such as Legionella pneumophila, Mycobacterium avium, and Hartmanella vermiformis increased significantly with phosphate concentration increasing. Based on X-ray powder diffractometer and zeta potentials measurement, trace phosphate did change physicochemical properties of corrosion products, hence promoting microbes escape from corrosion products to bulk water to a certain extent. Stimulated by chlorine disinfectant and phosphate, the extracellular polymeric substances (EPS) from the suspended biofilms of AR-0.6 gradually exhibited superior characteristics including higher content, flocculating efficiency, hydrophobicity and tightness degree, contributing to formation of large-scale suspended biofilms with strong chlorine-resistance ability. However, the disinfection by-products concentration in DWDSs barely changed due to the balance of EPS precursors contribution and biodegradation effect, covering up the microbiological water quality risk. Therefore, more attention should be paid to the trace phosphorus polluted water source though its concentration was much lower than wastewater. This is the first study successfully revealing the influence mechanism of trace phosphate on microbial stability in DWDSs, which may help to fully understand the biofilms transformation and microbial community succession in DWDSs.
研究了水源中痕量磷酸盐浓度（0、0.3 和 0.6mg/L）对饮用水分配系统（DWDS）微生物稳定性的影响。显然，结果验证了在通过环形反应器（AR）模拟的 DWDS 出水中，总微生物生物量和机会性病原体（如嗜肺军团菌、鸟分枝杆菌和蠕形螺旋体）的绝对浓度随着磷酸盐浓度的增加而显著增加。基于 X 射线粉末衍射仪和动电电位测量，痕量磷酸盐确实改变了腐蚀产物的物理化学性质，从而在一定程度上促进微生物从腐蚀产物逃到主体水中。在氯消毒剂和磷酸盐的刺激下，AR-0.6 悬浮生物膜中的细胞外聚合物物质（EPS）逐渐表现出更高的特性，包括更高的含量、絮凝效率、疏水性和紧密程度，有助于形成具有较强抗氯能力的大规模悬浮生物膜。然而，由于 EPS 前体贡献和生物降解作用的平衡，DWDS 中的消毒副产物浓度几乎没有变化，掩盖了微生物水质风险。因此，尽管其浓度远低于废水，但应更加关注受痕量磷污染的水源。这是首次成功揭示痕量磷酸盐对 DWDS 中微生物稳定性影响的机制的研究，这可能有助于充分了解 DWDS 中的生物膜转化和微生物群落演替。
