许多采用氯胺化进行二次消毒的公用事业公司都遇到了配水系统中硝化细菌生长的问题。这项研究涉及应用分子生物学技术，探索在三个完整的氯胺化系统中生长的氨氧化细菌（AOB）和亚硝酸盐氧化细菌（NOB）的类型，显示硝化事件的化学证据。结果表明，亚硝基单胞菌在AOB种群中普遍占优势，除一个样本外，亚硝基螺旋藻在所有AOB群落中占可忽略或很小的比例。 克隆和测序证明存在寡养亚硝基单胞菌群代表。在NOB群落中，大多数样本中检测到了硝基螺旋体，而只有少数样本中检测到了硝化杆菌。这些结果提供了对氯胺化系统中负责硝化事件的AOB类型的见解，这将有助于指导未来旨在表征相关AOB生长和失活特性的研究。此外，在大多数样品中检测到NOB表明，需要评估生物亚硝酸盐氧化相对于氯胺残留在这些系统中的化学氧化的贡献。 包括37个参考文献、表格、图表。

Many utilities that have implemented chloramination for secondary disinfection experience problems with the growth of nitrifying bacteria in the distribution system. This study involved the application of molecular biology techniques to explore the types of ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) growing in three full-scale chloraminated systems showing chemical evidence of a nitrification episode. The results indicated a general dominance of the AOB populations by Nitrosomonas species, with Nitrosospira constituting a negligible or small fraction of the AOB community in all but one sample. Cloning and sequencing demonstrated the presence of Nitrosomonas oligotropha cluster representatives. For the NOB communities, Nitrospira were detected in most of the samples, while Nitrobacter were only detected in a few samples. These results provide insight into the types of AOB responsible for nitrification episodes in chloraminated systems, which should help direct future studies aimed at characterizing relevant AOB growth and inactivation properties. Also, the detection of NOB in most of the samples suggests a need to evaluate the contribution of biological nitrite oxidation relative to chemical oxidation by chloramine residual in these systems. Includes 37 references, tables, figures.