Petterson S R, Stenström T A
Water & Health Pty Ltd, P.O. Box 648, Salamander Bay 2317, Australia and Department of Mathematical Sciences and Technology, Norwegian University of Life Sciences, Ås, Norway E-mail:
Durban University of Technology, SARChi Chair, Institute for Water and Wastewater Technology, Durban University of Technology, P.O. Box 1334, Durban 4000, South Africa.
J Water Health. 2015 Sep;13(3):625-44. doi: 10.2166/wh.2015.193.
To support the implementation of quantitative microbial risk assessment (QMRA) for managing infectious risks associated with drinking water systems, a simple modeling approach for quantifying Log10 reduction across a free chlorine disinfection contactor was developed. The study was undertaken in three stages: firstly, review of the laboratory studies published in the literature; secondly, development of a conceptual approach to apply the laboratory studies to full-scale conditions; and finally implementation of the calculations for a hypothetical case study system. The developed model explicitly accounted for variability in residence time and pathogen specific chlorine sensitivity. Survival functions were constructed for a range of pathogens relying on the upper bound of the reported data transformed to a common metric. The application of the model within a hypothetical case study demonstrated the importance of accounting for variable residence time in QMRA. While the overall Log10 reduction may appear high, small parcels of water with short residence time can compromise the overall performance of the barrier. While theoretically simple, the approach presented is of great value for undertaking an initial assessment of a full-scale disinfection contactor based on limited site-specific information.
为支持实施定量微生物风险评估（QMRA）以管理与饮用水系统相关的感染风险，开发了一种用于量化通过自由氯消毒接触器的Log10去除率的简单建模方法。该研究分三个阶段进行：首先，回顾文献中发表的实验室研究；其次，开发一种将实验室研究应用于实际规模条件的概念方法；最后，对一个假设的案例研究系统进行计算。所开发的模型明确考虑了停留时间的变异性和病原体对氯的特定敏感性。针对一系列病原体构建了生存函数，这些函数依赖于报告数据的上限并转换为通用指标。该模型在一个假设案例研究中的应用证明了在QMRA中考虑可变停留时间的重要性。虽然总体Log10去除率可能看起来很高，但停留时间短的小部分水可能会损害屏障的整体性能。虽然从理论上讲很简单，但所提出的方法对于基于有限的特定场地信息对实际规模的消毒接触器进行初步评估具有很大价值。
