Development criteria for ultraviolet disinfection of unfiltered drinking water

紫外线（UV）光已被证明对水生寄生虫如隐孢子虫和贾第鞭毛虫有效，并迅速被用于水处理，用于过滤饮用水的消毒。 紫外线用于劣质水源，如未经过滤的地表水，一直受到限制，因为人们对水中颗粒和其他杂质对紫外线消毒效果的影响知之甚少。 拟议研究的广泛目标是提高对水质变量（如微生物浓度、颗粒物、溶解和胶体有机物）如何影响未过滤天然水的微生物紫外线消毒的认识。 将在实验室实验中研究隐孢子虫卵囊、枯草芽孢杆菌孢子和其他替代微生物与未过滤天然水和合成水基质中存在的颗粒的聚集和相互作用。 还将开发一种对含有低浓度接种微生物的水样进行紫外线照射的方法。 由于隐孢子虫的研究非常昂贵且困难，因此将使用替代微生物进行UV灭活研究。 将测量各种未过滤天然水和合成水基质中替代微生物的聚集和颗粒相互作用，并将其与台式UV暴露实验中测量的灭活水平相关联。 这项研究的预期最终产品是一个水质指数或一个方便的标准测试，可用于水处理工程师预测当紫外线用于消毒特定的未经过滤的供水时提供的公共卫生保护水平。

Ultraviolet (UV) light has been shown to be effective against waterborne parasites such as Cryptosporidium and Giardia and is rapidly being adopted in water treatment for disinfection of filtered drinking water.   The use of UV for poor quality water sources, such as unfiltered surface water, has been limited because the effect of particles and other impurities in the water on the effectiveness of UV disinfection is poorly understood.   The broad objective of the proposed research is to improve the knowledge of how water quality variables such as microorganism concentration, particulate matter, and dissolved and colloidal organic matter, affect UV disinfection of microorganisms unfiltered natural water.  Aggregation and interaction of Cryptosporidium oocyst, Bacillus subtilis spores and other surrogate microorganisms with particles present in unfiltered natural water and synthetic water matrices will be investigated in laboratory experiments.  A method for conducting UV exposures with water samples containing low concentrations of seeded microorganisms will also be developed.   Because research with Cryptosporidium is very expensive and difficult, surrogate microorganisms will be used for UV inactivation studies.   Aggregation and particle-interaction of surrogate microorganisms in a variety of unfiltered natural water and synthetic water matrices will be measured and correlated with the level of inactivation measured in bench-top UV exposure experiments.  The anticipated end product of this research is a water quality index or a convenient standard test that could be used by water treatment engineers to predict the level of public health protection provided when UV is used to disinfect specific unfiltered water supplies.