National Institute for Public Health and the Environment, Expert Centre for Methodology and Information Services, PO Box 1, 3720 BA Bilthoven, The Netherlands.
Water Res. 2013 May 1;47(7):2592-602. doi: 10.1016/j.watres.2013.02.027. Epub 2013 Feb 27.
Slow sand filtration (SSF) in drinking water production removes pathogenic microorganisms, but detection limits and variable operational conditions complicate assessment of removal efficiency. Therefore, a model was developed to predict removal of human pathogenic viruses and bacteria as a function of the operational conditions. Pilot plant experiments were conducted, in which bacteriophage MS2 and Escherichia coli WR1 were seeded as model microorganisms for pathogenic viruses and bacteria onto the filters under various temperatures, flow rates, grain sizes and ages of the Schmutzdecke. Removal of MS2 was 0.082-3.3 log10 and that of E. coli WR1 0.94-4.5 log10 by attachment to the sand grains and additionally by processes in the Schmutzdecke. The contribution of the Schmutzdecke to the removal of MS2 and E. coli WR1 increased with its ageing, with sticking efficiency and temperature, decreased with grain size, and was modelled as a logistic growth function with scale factor f0 and rate coefficient f1. Sticking efficiencies were found to be microorganism and filter specific, but the values of f0 and f1 were independent of microorganism and filter. Cross-validation showed that the model can be used to predict log removal of MS2 and ECWR1 within ±0.6 log. Within the range of operational conditions, the model shows that removal of microorganisms is most sensitive to changes in temperature and age of the Schmutzdecke.
慢砂滤（SSF）在饮用水生产中可以去除致病微生物，但由于检测限和可变的操作条件，使得去除效率的评估变得复杂。因此，开发了一种模型来预测人类致病病毒和细菌的去除效率，作为操作条件的函数。进行了中试实验，在不同温度、流速、沙粒大小和 Schmutzdecke 老化程度下，将噬菌体 MS2 和大肠杆菌 WR1 作为致病病毒和细菌的模型微生物接种到过滤器上。MS2 的去除率为 0.082-3.3 log10，而 E. coli WR1 的去除率为 0.94-4.5 log10，这是通过附着在沙粒上以及 Schmutzdecke 中的过程实现的。Schmutzdecke 对 MS2 和 E. coli WR1 的去除贡献随着其老化而增加，随着附着效率和温度的降低，随着沙粒大小的降低而增加，并被建模为具有比例因子 f0 和速率系数 f1 的逻辑增长函数。附着效率是微生物和过滤器特有的，但 f0 和 f1 的值与微生物和过滤器无关。交叉验证表明，该模型可用于预测 MS2 和 ECWR1 的对数去除率在±0.6 log 范围内。在操作条件范围内，该模型表明微生物的去除对 Schmutzdecke 温度和老化的变化最敏感。
