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DEVELOPMENT OF A CT QUATION FOR THE INACTIVATION OF CRYPTOSPORIDIUM OOCYSTS BY CHLORINE DIOXIDE
Citation:
Clark*, R M., M Sivaganesan, E W. Rice*, AND J. Chen. DEVELOPMENT OF A CT QUATION FOR THE INACTIVATION OF CRYPTOSPORIDIUM OOCYSTS BY CHLORINE DIOXIDE. Henze, M. (ed.), WATER RESEARCH. Elsevier Science Ltd, New York, NY, 37(11):2773-2783, (2003).
Description:
Cryptosporidium parvum, a protozoan parasite that is highly resistant to chlorine, has been implicated in a number of waterborne disease outbreaks. This organism appears, however, to be efectively controlled by other oxidants such as chlorine dioxide or ozone. A major element of the USEPA's strategy for controlling C. parvum (oocysts) in drinking water is the use of Ct (concentration of disinfectant in mg/L times time in minutes) values. To support this strategy a Ct equation, based on first order kinetics, is proposed to provide guidance to drinking water utilities for the application of chlorine dioxide for controlling C. parvum oocysts. The equation is based on standard statistical techniques using available bench scale data. It can predict mean inactivation levels as well as a statistically conservative upper bound Ct value. This upper bound could be used to insure an appropriate safety factor for the protection of public health. It ws found that "lot" and the method for measuring inactivation contributed significantly to the variability in the model. Temperature had a major impact on inactivation rate. The upper-found model was found to be conservative with regard to estimating Ct values for inactivation.