C × T values are influenced by which factors?

• A. pH and temperature
• B. Concentration of chlorine and water pressure
• C. Concentration of chlorine, contact time, pH, and temperature
• D. Contact time and turbidity

Answer: (C)

C × T values, which represent the product of the concentration of a disinfectant and the time of contact, are critical for assessing the effectiveness of disinfection processes in water treatment. The factors that influence these values include both the concentration of the disinfectant, such as chlorine, and the duration the water is in contact with the disinfectant.

When considering the factors influencing C × T values, the concentration of chlorine is vital because higher concentrations of the disinfectant can yield a greater disinfection effect in a shorter time. Likewise, contact time plays a crucial role; the longer the disinfectant is in contact with pathogens, the more effective it will be at neutralizing them.

Additionally, both pH and temperature significantly affect the efficacy of chlorine as a disinfectant. For example, chlorine is more effective at lower pH levels, and temperature can influence the reaction rates of disinfection processes.

Thus, the answer correctly encapsulates all the relevant factors that impact C × T values, highlighting the importance of ensuring adequate concentrations of chlorine, sufficient contact time, and appropriate pH and temperature conditions for effective disinfection in water treatment systems.