AWWA WQTC55200

This paper presents a statistical analysis of UV dose response data for viruses, Cryptosporidium, and Giardia. The work was performed to support USEPA in developing criteria for the application of UV light to drinking water disinfection. Under an Agreement in Principle for the upcoming Stage 2 Microbial and Disinfection Byproducts Rules, EPA has agreed to develop tables specifying UV doses needed to achieve up to 3-log inactivation of Giardia lamblia, up to 3-log inactivation of Cryptosporidium, and up to 4-log inactivation of viruses. The authors analyzed data for two viruses, rotavirus and adenovirus, using regression analysis. Prediction intervals were used to determine the probability of a specific log inactivation as a function of UV dose for the viruses. Because many of the Cryptosporidium and Giardia lamblia inactivation data were reported as greater than a particular value, the authors analyzed these data using logistic regression. In addition to the statistical analysis, the authors developed capital and operations and maintenance (O & M) costs at three UV doses to compare the impact of UV dose on these costs. Includes 34 references, tables, figures.