Zhejiang Key Laboratory of Drinking Water Safety and Distribution Technology, Zhejiang University, Hangzhou, 310058, PR China.
Zhejiang Key Laboratory of Drinking Water Safety and Distribution Technology, Zhejiang University, Hangzhou, 310058, PR China; Ocean College, Zhejiang University, Hangzhou, 310058, PR China.
Environ Pollut. 2023 Dec 1;338:122716. doi: 10.1016/j.envpol.2023.122716. Epub 2023 Oct 11.
The issue of biofilm-related disinfection byproducts (DBPs) in drinking water distribution system (DWDS) has garnered significant attention. This study sought to examine the changes in biofilm-originated halogenated DBP formation potential (biofilm DBP-FP) in simulated continuous-flow DWDSs subjected to sequential UV and chlorine disinfection (UV-Cl) treatments with varying UV doses and to propose the underlying mechanism. The formation potential of trihalomethanes (THMs), haloacetic acids (HAAs), and the total organic halogen (TOX, X = Cl and Br) produced by biofilm were measured. Results showed that the biofilm TOCl-FP was at a minimum with a UV dose of 80 mJ/cm, corresponding to the lowest amounts of protein and polysaccharides in the extracellular polymeric substances (EPS). Sphingobium, Methylobacterium, and Sphingomonas played a crucial role in protein and polysaccharide biosynthesis. Bacterial community composition characterization together with metabolic function analysis indicated that dominant bacteria varied and metabolic function shifted due to UV-Cl disinfection, with Alphaproteobacteria increasing in relative abundance and Bacteroidia showing the opposite trend with increasing UV doses. Correlation analysis suggested that the UV-Cl disinfection process led to changes in the water matrix, including organics, inorganics, bacteria, and components that provide environmental pressure for the biofilm. These changes ultimately influenced the properties of the biofilm EPS, which had a direct impact on biofilm DBP-FP.
生物膜相关消毒副产物（DBPs）在饮用水分配系统（DWDS）中的问题引起了广泛关注。本研究旨在考察模拟连续流 DWDS 中生物膜起源的卤代 DBPs 形成潜力（biofilm DBP-FP）在连续 UV 和氯消毒（UV-Cl）处理下随 UV 剂量变化的变化，并提出潜在机制。测量了生物膜产生的三卤甲烷（THMs）、卤乙酸（HAAs）和总有机卤素（TOX，X=Cl 和 Br）的形成潜力。结果表明，当 UV 剂量为 80 mJ/cm 时，生物膜 TOCl-FP 最低，这与细胞外聚合物（EPS）中蛋白质和多糖的含量最低相对应。鞘氨醇单胞菌、甲基杆菌和鞘氨醇单胞菌在蛋白质和多糖生物合成中起关键作用。细菌群落组成特征与代谢功能分析表明，由于 UV-Cl 消毒，优势细菌发生变化，代谢功能发生转移，随着 UV 剂量的增加，α变形菌的相对丰度增加，而拟杆菌则呈相反趋势。相关分析表明，UV-Cl 消毒过程导致水基质发生变化，包括有机物、无机物、细菌和为生物膜提供环境压力的成分。这些变化最终影响生物膜 EPS 的特性，这对生物膜 DBP-FP 有直接影响。
