The results from this research affirmed the fact that inactivation of microorganisms by chemical disinfectants is influenced by disinfection, microbial, and water quality factors and the various interactions between these factors. The results showed that for all disinfectants, temperature is a key parameter that influences disinfection efficiency. The effect of turbidity was generally of less importance than pH and temperature. The safety factors (1.5 to 2.0) that are applied in the USEPA Ct tables should be satisfactory to account for these effects, not to mention the additional safety factors that are employed during Ct calculations (Cresidual and t10). Research Partner: USEPA Originally published by AwwaRF for its subscribers in 2003