Assessment of ultraviolet disinfection for unfiltered water supplies

对饮用水进行紫外线(UV)消毒是一种有效且日益流行的方法，可以灭活公共卫生关注的耐氯病原体。在加拿大，紫外线处理了超过21%的饮用水，最近对处理设施的调查表明，这项技术是提高消毒效率的最佳选择。由于天然水域中的微粒和其他物质会阻挡或反射光线而干扰消毒过程，因此建议在过滤后使用紫外线。然而，过滤并不是普遍实行的，一些未过滤的水供应利用紫外线进行消毒。关于未经过滤的水的紫外线有效性的知识存在差距，必须在保护公共健康的一系列条件下很好地了解其性能。 拟议的工作旨在通过量化各种未经过滤的水质条件与紫外线有效性之间的关系来解决知识差距问题。两个将紫外线应用于未经过滤的水的全规模处理设施将作为模型并提供具有代表性的样品。在暴露于准直紫外光后，将通过标准化微生物生物检测来确定所实现的消毒效果。利用实验数据，将考虑当前监测和业务做法的充分性。这项工作还将研究如何提高紫外线监测方案的准确性，以确保即使在具有挑战性的水源条件下也能实现消毒。项目成果将包括新的数据，以促进在加拿大设施中对未过滤供水进行紫外线消毒的行业最佳实践。

Ultraviolet (UV) disinfection of drinking water is an effective and increasingly popular method to inactivate chlorine-resistant pathogens of public health concern. In Canada, UV treats over 21% of all drinking water, and recent surveys of treatment facilities identify this technology as a top choice for increasing disinfection effectiveness. Since particulates and other material in natural waters can interfere with the disinfection process by blocking or reflecting light, it is recommended that UV be applied after filtration. However, filtration is not practiced universally, and several unfiltered water supplies utilize UV for disinfection. There are gaps in knowledge regarding UV effectiveness for unfiltered waters, and performance must be well understood under a range of conditions for the protection of public health. The proposed work aims to address knowledge gaps by quantifying relationships between a wide range of unfiltered water quality conditions and UV effectiveness. Two full-scale treatment facilities that apply UV to unfiltered waters will be used as models and to provide representative samples. Disinfection achieved will be identified through standardized microorganism bioassays after exposure to collimated UV light. Using experimental data, the adequacy of current monitoring and operational practices will be considered. This work will also look at ways to improve the accuracy of UV monitoring protocols to ensure that disinfection can be achieved even with challenging source water conditions. Project outcomes will include new data to advance industry best practices in UV disinfection of unfiltered water supplies at Canadian facilities.