Chalmers University of Technology, Department of Civil and Environmental Engineering, Water Environment Technology, SE-412 96 Gothenburg, Sweden.
Norwegian University of Life Sciences NMBU, Department of Mathematical Sciences and Technology, P.O. Box 5003, NO-1432 Ås, Norway; Water & Health Pty Ltd. P.O. Box 648 Salamander Bay, 2317, Australia.
Sci Total Environ. 2015 Sep 1;526:177-86. doi: 10.1016/j.scitotenv.2015.04.040. Epub 2015 Apr 28.
Norovirus contamination of drinking water sources is an important cause of waterborne disease outbreaks. Knowledge on pathogen concentrations in source water is needed to assess the ability of a drinking water treatment plant (DWTP) to provide safe drinking water. However, pathogen enumeration in source water samples is often not sufficient to describe the source water quality. In this study, the norovirus concentrations were characterised at the contamination source, i.e. in sewage discharges. Then, the transport of norovirus within the water source (the river Göta älv in Sweden) under different loading conditions was simulated using a hydrodynamic model. Based on the estimated concentrations in source water, the required reduction of norovirus at the DWTP was calculated using quantitative microbial risk assessment (QMRA). The required reduction was compared with the estimated treatment performance at the DWTP. The average estimated concentration in source water varied between 4.8×10(2) and 7.5×10(3) genome equivalents L(-1); and the average required reduction by treatment was between 7.6 and 8.8 Log10. The treatment performance at the DWTP was estimated to be adequate to deal with all tested loading conditions, but was heavily dependent on chlorine disinfection, with the risk of poor reduction by conventional treatment and slow sand filtration. To our knowledge, this is the first article to employ discharge-based QMRA, combined with hydrodynamic modelling, in the context of drinking water.
诺如病毒污染饮用水水源是导致水源性疾病暴发的一个重要原因。为了评估饮用水处理厂（DWTP）提供安全饮用水的能力，需要了解水源中病原体的浓度。然而，对水源水样中的病原体进行计数通常不足以描述水源水质。在本研究中，我们对污染源头（即污水排放口）的诺如病毒浓度进行了特征描述。然后，利用水动力模型模拟了在不同负荷条件下，诺如病毒在水源（瑞典的 Göta älv 河）中的迁移情况。基于水源中估计的浓度，使用定量微生物风险评估（QMRA）计算了 DWTP 中所需的诺如病毒去除率。将所需的去除率与 DWTP 的估计处理性能进行了比较。估计的水源中平均浓度在 4.8×10(2)到 7.5×10(3)基因组当量 L(-1)之间；处理所需的平均去除率在 7.6 到 8.8 Log10 之间。DWTP 的处理性能估计足以应对所有测试的负荷条件，但严重依赖于氯消毒，存在常规处理和慢滤砂去除效果不佳的风险。据我们所知，这是第一篇在饮用水背景下，采用基于排放的 QMRA 并结合水动力模型的文章。
