PDF(Pubmed)
Abstract：
Water age in drinking water systems is often used as a proxy for water quality but is rarely used as a direct input in assessing microbial risk. This study directly linked water ages in a premise plumbing system to concentrations of Legionella pneumophila via a growth model. In turn, the L. pneumophila concentrations were used for a quantitative microbial risk assessment to calculate the associated probabilities of infection (Pinf) and clinically severe illness (Pcsi) due to showering. Risk reductions achieved by purging devices, which reduce water age, were also quantified. The median annual Pinf exceeded the commonly used 1 in 10,000 (10-4) risk benchmark in all scenarios, but the median annual Pcsi was always 1-3 orders of magnitude below 10-4. The median annual Pcsi was lower in homes with two occupants (4.7 × 10-7) than with one occupant (7.5 × 10-7) due to more frequent use of water fixtures, which reduced water ages. The median annual Pcsi for homes with one occupant was reduced by 39-43% with scheduled purging 1-2 times per day. Smart purging devices, which purge only after a certain period of nonuse, maintained these lower annual Pcsi values while reducing additional water consumption by 45-62%.
摘要：
饮用水系统中的水龄通常用作水质的代表，但很少用作评估微生物风险的直接输入。这项研究通过生长模型将前提管道系统中的水年龄与嗜肺军团菌的浓度直接联系起来。反过来,我们将嗜肺乳杆菌浓度用于定量微生物风险评估,以计算淋浴引起的感染(Pinf)和临床严重疾病(Pcsi)的相关概率.通过吹扫装置实现的风险降低，减少水的年龄，也是量化的。年Pinf中位数在所有情景中都超过了常用的万分之一（10-4）风险基准，但年Pcsi的中位数总是低于10-4的1-3个数量级。由于更频繁地使用水装置，有两个居住者（4.7×10-7）的家庭的年度Pcsi中位数低于一个居住者（7.5×10-7）。减少了水的年龄。每天计划清除1-2次，有一名居住者的房屋的年度Pcsi中位数减少了39-43％。智能净化装置,只有在一段时间不使用后才能清除，保持这些较低的年度Pcsi值，同时减少45-62%的额外用水量。
