AWWA WQTC69238

This powerpoint presentation begins by providing a brief overview of the criticality of disinfection, the use of chlorine and monochloramine as disinfectants, U.S. Environmental Protection Agency (USEPA) disinfection requirements, and the USEPA Contaminant Candidate List 2 (CCL2) viruses for potential regulation. A brief overview is provided of previous research in Reagent Grade Water (RGW) and natural waters on chlorine, monochlorine, multiple viruses. AwwaRF Project 3134 study objectives are presented and include the following: relative resistance of study viruses; effect of pH; effect of temperature; effect of disinfectant concentration; effect of water quality; and, free chlorine vs. monochloramine. Experimental methods are presented, including: specific viruses used; baseline experimental conditions; treated source water (TSW) experimental conditions; experiments conducted in recirculating water bath (d 5 hr) or in environmental chamber (e 5 hr); inactivation data obtained using tissue culture plaque assays; inactivation curves plotted using EFH model in Excel; and, viral inactivation measured by calculating Ct value (conc. x time) for 2, 3, and 4 log reduction. Presentation conclusions indicate the following: pH and temperature trends followed previous disinfection kinetic theory; in general, increased disinfectant concentration did not always result in a proportional increase in disinfection rate; disinfection was most effective for MNV; chlorine disinfection was least effective for CVB5; monochloramine disinfection was least effective for AdV2 and E11; and, disinfection for some viruses was markedly different between different water types. Thus, it is important to consider virus susceptibility for a range of natural water types when evaluating the potential efficacy of disinfectants. Includes figures.