Transfers, Interfaces and Processes - Chemical Engineering Unit, Université Libre de Bruxelles, Av. F.D. Roosevelt 50, CP 165/67, 1050 Brussels, Belgium.
Water Res. 2012 Nov 15;46(18):5893-903. doi: 10.1016/j.watres.2012.07.052. Epub 2012 Aug 7.
In this work, the ozone inactivation of resistant microorganisms is studied and a method to assess the efficiency of a drinking water plant to inactivate resistant microorganisms using ozone is proposed. This method aims at computing the fraction of resistant microorganisms that are not inactivated at the exit of an ozonation step by evaluating the duration of the lag phase of the ozone inactivation of these microorganisms and the contact time distribution of these microorganisms with the ozone in the step. To evaluate the duration of the lag phase of the ozone inactivation of resistant pathogenic microorganisms, an experimental procedure is proposed and applied to Bacillus subtilis spores. The procedure aims at characterizing the ozone inactivation kinetics of B. subtilis spores for different temperature and ozone concentration conditions. From experimental data, a model of the ozone inactivation of B. subtilis spores is built. One of the parameters of this model is called the lag time and it measures the duration of the lag phase of the ozone inactivation of B. subtilis spores. This lag time is identified for different temperature and ozone concentration conditions in order to establish a correlation between this lag time and the temperature and ozone concentration conditions. To evaluate the contact time distribution between microorganisms and the ozone in a disinfection step of a drinking water plant, a computational fluid dynamics tool is used. The proposed method is applied to the ozonation channel of an existing drinking water plant located in Belgium and operated by Vivaqua. Results show that lag times and contact times are both in the same order of magnitude of a few minutes. For a large range of temperatures and ozone concentrations in the Tailfer ozonation channel and for the highest hydraulic flow rate applied, a significant fraction of resistant microorganisms similar to B. subtilis spores is not inactivated.
在这项工作中，研究了臭氧对抗性微生物的灭活作用，并提出了一种评估饮用水厂利用臭氧灭活抗性微生物效率的方法。该方法旨在通过评估这些微生物的臭氧灭活滞后期的持续时间以及这些微生物在步骤中与臭氧的接触时间分布，计算出未被臭氧灭活的抗性微生物的分数。为了评估抗性致病微生物的臭氧灭活滞后期的持续时间，提出并应用了一种实验程序来评估枯草芽孢杆菌孢子的臭氧灭活动力学。该程序旨在针对不同的温度和臭氧浓度条件来表征枯草芽孢杆菌孢子的臭氧灭活动力学。从实验数据中，建立了枯草芽孢杆菌孢子的臭氧灭活模型。该模型的一个参数称为滞后时间，它衡量了枯草芽孢杆菌孢子的臭氧灭活滞后期的持续时间。为了建立滞后时间与温度和臭氧浓度条件之间的相关性，针对不同的温度和臭氧浓度条件确定了该滞后时间。为了评估饮用水厂消毒步骤中微生物与臭氧之间的接触时间分布，使用了计算流体动力学工具。该方法应用于位于比利时并由 Vivaqua 运营的现有饮用水厂的臭氧通道。结果表明，滞后时间和接触时间都处于几分钟的相同数量级。对于 Tailfer 臭氧通道中的大范围温度和臭氧浓度以及应用的最高水力学流速，类似于枯草芽孢杆菌孢子的大量抗性微生物未被灭活。
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