AWWA WQTC58818

With the recent recognition of ultraviolet (UV) disinfection effectiveness for protozoan cysts and oocysts, there has been an increase in interest in the full range of possible drinking water applications for UV. However, drinking water studies to date have concentrated primarily on filtered waters with low turbidities and relatively low organic and algae concentrations. By identifying and understanding the impact of turbidity, algae, and organics on UV efficacy, utilities can consider the broader range of UV applications which could include groundwater, pre-filtration, post bank filtration, disinfection of unfiltered water supply, open reservoir treatment, and others. Our partial understanding of the impact of these constituents not only limits the application of UV disinfection, it could also lead to an inappropriate application of UV technology. In addition to the possible advantages offered by UV for disinfection, it is possible to significantly alter oxidation techniques and disinfection byproduct (DBP) formation. Understanding the possible impacts on DBPs, both concentration and type, is essential for comprehensive public health planning. Additional research into possible DBP compliance strategies offered by UV is necessary to complete this picture. This paper discusses results from a 14-month AWWARF sponsored project in Winnipeg, Canada (pop. 630,000), which evaluated UV disinfection and DBP characterization for the City's unfiltered water supply. The City's water supply and treatment system offered a unique opportunity to investigate UV disinfection of an unfiltered supply as well as a wide range of precursor concentrations and oxidant and disinfectant combinations that are not usually present in filtered water supplies. Includes 3 references, tables, figures.