Zheng Songyuan, Lin Tao, Zhang Xue, Jiang Fuchun
Ministry of Education Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Hohai University, Nanjing, 210098, PR China; College of Environment, Hohai University, Nanjing, 210098, PR China.
Ministry of Education Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Hohai University, Nanjing, 210098, PR China; College of Environment, Hohai University, Nanjing, 210098, PR China.
Chemosphere. 2023 Dec;344:140382. doi: 10.1016/j.chemosphere.2023.140382. Epub 2023 Oct 6.
Residual chlorine and biofilm coexistence is inevitable in drinking water transmission and distribution networks. Understanding the microbial response and its mediated effects on disinfection byproducts under different categories of residual chlorine stress is essential to ensure water safety. The aim of our study was to determine the response of pipe wall biofilms to residual chlorine pressure in chlorine and chloramine systems and to understand the microbially mediated effects on the formation and migration of haloacetonitriles (HANs), typical nitrogenous disinfection byproducts. According to the experimental results, the biofilm response changes under pressure, with significant differences noted in morphological characteristics, the extracellular polymeric substances (EPS) spatial structure, bacterial diversity, and functional abundance potential. Upon incubation with residual chlorine (1.0 ± 0.2 mg/L), the biofilm biomass per unit area, EPS, community abundance, and diversity increased in the chloramine group, and the percentage of viable bacteria increased, potentially indicating that the chloramine group provides a richer variety of organic matter precursors. Compared with the chloramine group, the chlorination group exhibited increased haloacetonitrile formation potential (HANFP), with Rhodococcus (43.2%) dominating the system, whereas the prediction abundance of metabolic functions was advantageous, especially with regard to amino acid metabolism, carbohydrate metabolism, and the biodegradation and metabolism of foreign chemicals. Under chlorine stress, pipe wall biofilms play a stronger role in mediating HAN production. It is inferred that chlorine may stimulates microbial interactions, and more metabolites (e.g., EPS) consume chlorine to protect microbial survival. EPS dominates in biofilms, in which proteins exhibit greater HANFP than polysaccharides.
在饮用水输配管网中，余氯与生物膜共存是不可避免的。了解不同类别余氯胁迫下微生物的响应及其对消毒副产物的介导作用对于确保供水安全至关重要。我们研究的目的是确定管壁生物膜在氯和氯胺体系中对余氯压力的响应，并了解其对典型含氮消毒副产物卤乙腈（HANs）形成和迁移的微生物介导作用。根据实验结果，生物膜在压力下的响应会发生变化，在形态特征、胞外聚合物（EPS）空间结构、细菌多样性和功能丰度潜力方面存在显著差异。在与余氯（1.0±0.2mg/L）孵育后，氯胺组中单位面积生物膜生物量、EPS、群落丰度和多样性增加，活菌百分比增加，这可能表明氯胺组提供了更丰富的有机物质前体。与氯胺组相比，氯化组的卤乙腈形成潜力（HANFP）增加，红球菌属（43.2%）在系统中占主导地位，而代谢功能的预测丰度具有优势，尤其是在氨基酸代谢、碳水化合物代谢以及外源化学物质的生物降解和代谢方面。在氯胁迫下，管壁生物膜在介导HAN生成方面发挥着更强的作用。据推测，氯可能刺激微生物相互作用，更多的代谢产物（如EPS）消耗氯以保护微生物存活。EPS在生物膜中占主导地位，其中蛋白质比多糖表现出更大的HANFP。
