为敏感人群提供二次配水系统的众多设施 正在寻找合适的进入点（POE）消毒技术，以减少 远端出口出现军团菌。二氧化氯已在欧洲成功使用 并开始作为POE消毒技术出现在美国。 二氧化氯是一种有效的消毒剂，能够杀死许多水传播的病原体 包括军团菌、大肠杆菌、隐孢子虫、贾第虫等。 氯的能力 在易受感染的医院，用二氧化碳杀死饮用水中的军团菌是非常有意义的 患者可能有感染医院获得性退伍军人病的风险。POE消毒 为了控制病原体（尤其是军团菌），已经部署了一些技术 在二级配电系统内。这类技术相对较新，数据也很少 在全面应用中证明其有效性。 一项研究是在宾夕法尼亚州中部一家有437张床位的急诊医院（hospital）进行的。 该医院运营着一个二级配送系统，其中包括一个52万加仑的燃油 水库和10000英尺的配水管道，服务于14英亩以上的23栋建筑。市政的 供水量约占每日需求量的80%，而剩余的供水量则来自一个城市 现场氯化井。医院获得性退伍军人病病例的鉴定 促使医院实施环境监测计划并进行消毒 控制供水系统中的军团菌。 控制军团菌最初是由 将游离余氯保持在0.3-0.5 mg/L之间，并使用热消除法 方法1998年4月至2000年5月，但从逻辑上看，长期控制无效 难度大，成本高。曾考虑过铜银电离，但由于成本太高而被拒绝 在许多建筑物中安装电离装置。选择二氧化氯是因为它可以 安装在蓄水池中央，对所有建筑物内的水进行消毒，所需费用最低 并在欧洲和实验室研究的文献中进行了积极的回顾。 二氧化氯系统于2000年6月上线。2000年6月至1月 2001年，该医院结合每日监测，继续对军团菌进行环境监测 二氧化氯残留测量。2001年2月，制定了标准化的抽样方案 这包括每月从至少两个热水器和冷水器中收集100毫升水 八栋建筑的远端排水口、每栋建筑的水源和水库（~48 样品/月）。每月监测包括pH值、温度（C）、二氧化氯残留量 （DPD法；mg/L）和军团菌培养（CFU/ml）。在选定地点进行定期分析 包括总有机碳（Hach试验n管；ppm）和总消毒副产物形成量（离子色谱仪；ppm）。 包括14篇参考文献。

Numerous facilities operating secondary water distribution systems serving sensitive populations are searching for the appropriate point of entry (POE) disinfection technology to reduce the occurrence of Legionella at distal outlets. Chlorine dioxide has been successfully used in Europe and is beginning to appear in the United States as a POE disinfection technology. Chlorine dioxide is an effective disinfectant capable of killing numerous waterborne pathogens including Legionella, E. coli, Cryptosporidium, Giardia, and others. The ability of chlorine dioxide to kill Legionella in drinking water is of great interest to hospitals, where susceptible patients can be at risk of contracting hospital acquired Legionnaires' disease. POE disinfection technologies have been deployed in an effort to control pathogens (particularly Legionella) within secondary distribution systems. Such technologies are relatively new and few data exists to demonstrate effectiveness in full-scale applications. A study was implemented at a 437-bed acute care hospital in Central Pennsylvania (Hospital). The Hospital operates a secondary distribution system that includes a 520,000 gallon covered reservoir and 10,000 feet of distribution piping serving 23 buildings over 14 acres. Municipally supplied water accounts for ~80% of the daily demand, while the remaining supply is from an on-site chlorinated well. Identification of cases of hospital-acquired Legionnaires' disease prompted the Hospital to implement an environmental monitoring program and disinfection to control Legionella in the water distribution system. Control of Legionella was first attempted by maintaining a free chlorine residual between 0.3-0.5 mg/L and using a thermal eradication method from April 1998 - May 2000, but was ineffective for long-term control, logistically difficult, and costly. Copper-silver ionization was considered, but rejected because of the cost to install the ionization units in the many buildings. Chlorine dioxide was selected because it could be installed centrally at the reservoir to disinfect the water in all buildings, required minimal maintenance, and had a positive review in the literature from European and laboratory studies. The chlorine dioxide system was brought on-line in June 2000. From June 2000 to January 2001, the Hospital continued environmental surveillance for Legionella in conjunction with daily chlorine dioxide residual measurement. In February 2001 a standardized sampling protocol was initialized that included monthly collection of 100 ml of water from at least two hot and cold distal outlets in eight buildings, the source water to each building, and the reservoir (~48 samples/month). Monthly monitoring included pH, temperature (C), chlorine dioxide residual (DPD method; mg/L), and Legionella culture (CFU/ml). Periodic analysis at select locations include total organic carbon (Hach test.n tube; ppm) and total disinfection byproduct formation (ion chromatograph; ppm). Includes 14 references.