The objective of this study is to evaluate the influence of water distribution system conditions (pH, total organic carbon, residual chlorine, and phosphate) on haloacetic acids (HAAs) biodegradation. A series of batch microcosm tests were conducted to determine biodegradation kinetics and collected biomass was used for real time quantitative reverse transcription polymerase chain reaction analyses to monitor how these drinking water distribution system conditions affect the relative expression of bacterial dehalogenase genes. It was observed that tested water distribution system conditions affected HAA biodegradation with different removal efficiencies (0-100%). HAA biodegradation was improved in tested samples with TOC (3 mg/L) and pH 8.5 compared to those of TOC (0 mg/L) and pH 7, respectively. However, slight improvement was observed with the increased PO₄ concentration (3.5 mg/L), and the presence of residual chlorine even at low concentration prohibited biodegradation of HAAs. The observed trend in the relative expression of dehII genes was compatible with the HAA biodegradation trend. Overall relative expression ratio of dehII genes was lower at pH 7, phosphate (0.5 mg/L), and TOC (0 mg/L) in comparison with pH 8.5, phosphate (3.5 mg/L), and TOC (3 mg/L) in the same experimental conditions.

这项研究的目的是评估水分配系统条件（pH，总有机碳，残留氯和磷酸盐）对卤乙酸（HAAs）生物降解的影响。进行了一系列分批缩影测试，以确定生物降解动力学，并将收集到的生物量用于实时定量逆转录聚合酶链反应分析，以监测这些饮用水分配系统的条件如何影响细菌脱卤酶基因的相对表达。观察到，测试的水分配系统条件以不同的去除效率（0-100％）影响了HAA的生物降解。与TOC（0 mg / L）和pH 7相比，TOC（3 mg / L）和pH 8.5的测试样品中HAA的生物降解得到改善。然而，₄浓度（3.5 mg / L），即使在低浓度下也存在残留氯，这会阻止HAAs的生物降解。观察到的dehII基因相对表达趋势与HAA生物降解趋势兼容。与pH 8.5，磷酸盐（3.5 mg / L）和TOC（3 mg / L）相比，pH 7，磷酸盐（0.5 mg / L）和TOC（0 mg / L）时，dehII基因的总体相对表达率较低。 ）在相同的实验条件下进行。