AWWA WQTC52995

The objective of this study was to investigate the inactivation kineticsof Cryptosporidium parvum oocysts in sequential disinfection scenarios involving the use of ozone followed by either free or combined chlorine. Sequential disinfection experiments using ozone as the primary disinfectant and free or combined chlorine as the secondary disinfectant revealed that ozone pretreatment resulted in the removal of a more prominent CT lag observed for both chlorine species, when used alone. An additional benefit was that the rate of inactivation for ozone pretreated oocysts was significantly greater than that observed for the post lag phase portion of the inactivation curves obtained with free or combined chlorine alone. Includes 8 references, figure.