CT Values are an important part of calculating disinfectant dosage for the chlorination of drinking water.
[1] The disinfection kinetics are conventionally calculated via the Chick-Watson model, named for the work of Harriette Chick[2] and H. E.
The calculated CT value is the product of the disinfectant residual (in mg/L) and the detention time (in minutes), through the section at peak hourly flow.
[5] These tables express the required CT values to achieve a desired removal of microorganisms of interest in drinking water (e.g. Giardia lamblia cysts) for a given disinfectant under constant temperature and pH conditions.
CT Values for the Inactivation of Giardia Cysts by Free Chlorine at 5 °C and pH ≈ 7.0:[6] Full tables are much larger than this example and should be obtained from the regulatory agency for a particular jurisdiction.