通常需要停止使用氯胺进行残留消毒的系统 每年至少添加一个月的氨。这段时间被用来“燃烧”或 用高强度消毒剂“冲洗”系统，通常伴有 消防栓冲洗程序，确保氯化水完全通过 分配系统。之前的一项研究表明，从氯胺开始 通过异养细菌检测，去除余氯消毒剂可降低细菌水平 平板计数（HPC）；然而，这种影响是暂时的，因为水平再次升高 回到氯胺化后。在这项工作的基础上，项目目标之一是 检查从混合氯切换到游离氯，然后再切换到游离氯的效果 组合氯对两个相邻配水系统（DS-1和DS-1）中细菌水平的影响 DS-2），并将这些影响与水龄和水质联系起来 质量参数包括消毒剂残留量、可同化有机碳和 氮物种（硝酸盐、亚硝酸盐、氨）。 第二个项目目标是检查配电系统中的一个“死胡同”位置，以便 经过一段时间不可持续的氯残留后，细菌生长。此外，氮 对物种进行分析，以检查现场硝化的可能性。包括15个参考文献、表格和图表。

Systems utilizing chloramines for residual disinfection often are required to stop ammonia addition for at least one month per year. This time is utilized to "burn" or "flush" the system with a high strength disinfectant and is typically accompanied by a program of hydrant flushing to ensure the chlorinated water travels completely through the distribution system. A previous study indicated that switching from chloramines to free chlorine residual disinfectant reduced bacteria levels as measured by heterotrophic plate count (HPC); the effect was temporary, however, because the levels increased again upon return to chloramination. To build upon this work, one of the project goals was to examine the effect of switching from combined to free chlorine and then back to combined chlorine on bacteria levels in two neighboring distribution systems (DS-1 and DS-2) with similar raw water quality, and to link these effects to water age and water quality parameters including disinfectant residual, assimilable organic carbon, and nitrogen species (nitrate, nitrite, ammonia). A second project goal involved examining a "dead-end" site in the distribution system for bacterial growth after periods of unsustained chlorine residuals. Additionally, nitrogen species were analyzed to examine the possibility of nitrification at the site. Includes 15 references, table, figures.