AWWA Water Treatment Operator Certification 2025 – 400 Free Practice Questions to Pass the Exam

Chlorine is widely recognized as a primary disinfectant used in the treatment of drinking water. Its effectiveness in killing bacteria, viruses, and other pathogens makes it a crucial component in ensuring water safety. When chlorine is added to water, it reacts to form hypochlorous acid, which is a powerful antimicrobial agent. This process not only disinfects the water but also helps in maintaining residual chlorine levels, which provide ongoing protection against recontamination during distribution.

While fluoride is often added to drinking water for dental health benefits, it does not serve as a disinfectant. Calcium carbonate is typically used for pH adjustment and to prevent corrosion, rather than for disinfection purposes. Sodium hydroxide is primarily involved in pH control as well and does not have disinfectant properties. Thus, chlorine stands out as the key chemical for ensuring that drinking water is safe for consumption.