Propato Marco, Uber James G
Department of Civil and Environmental Engineering, University of Cincinnati, Cincinnati, Ohio 45221, USA.
Environ Sci Technol. 2004 Jul 1;38(13):3713-22. doi: 10.1021/es035271z.
Can the spread of infectious disease through water distribution systems be halted by a disinfectant residual? This question is overdue for an answer. Regulatory agencies and water utilities have long been concerned about accidental intrusions of pathogens into distribution system pipelines (i.e., cross-connections) and are increasingly concerned about deliberate pathogen contamination. Here, a simulation framework is developed and used to assess the vulnerability of a water system to microbiological contamination. The risk of delivering contaminated water to consumers is quantified by a network water quality model that includes disinfectant decay and disinfection kinetics. The framework is applied to two example networks under a worst-case deliberate intrusion scenario. Results show that the risk of consumer exposure is affected by the residual maintenance strategy employed. The common regulation that demands a "detectable" disinfectant residual may not provide effective consumer protection against microbial contamination. A chloramine residual, instead of free chlorine, may significantly weaken this final barrier against pathogen intrusions. Moreover, the addition of a booster station at storage tanks may improve consumer protection without requiring excessive disinfectant.
通过水分配系统传播的传染病能被消毒剂残留阻止吗？这个问题早就该有答案了。监管机构和自来水公司长期以来一直担心病原体意外侵入配水系统管道（即交叉连接），并且越来越担心蓄意的病原体污染。在此，开发了一个模拟框架并用于评估水系统对微生物污染的脆弱性。通过一个包括消毒剂衰减和消毒动力学的管网水质模型来量化向消费者输送受污染水的风险。该框架应用于最坏情况下蓄意侵入场景下的两个示例网络。结果表明，消费者接触风险受所采用的残留维持策略影响。要求有“可检测到的”消毒剂残留的常见规定可能无法为消费者提供有效的微生物污染防护。用氯胺残留而非游离氯，可能会显著削弱这一抵御病原体侵入的最后屏障。此外，在储水箱处增设增压站可能在无需过量消毒剂的情况下提高对消费者的保护。
