Which of the following is NOT a common disinfectant used in potable water treatment?

Calcium sulfate is not considered a common disinfectant in potable water treatment processes. It is primarily used as a coagulant or flocculant in water treatment to aid in the removal of particulates and improve sedimentation, but it does not possess the disinfecting properties needed to kill or inactivate pathogens in water.

In contrast, chlorine, ozone, and UV light are widely recognized as effective disinfectants. Chlorine is a traditional choice due to its potency against bacteria and viruses, and it also provides residual disinfection in the distribution system. Ozone is known for its strong oxidative properties, effectively eliminating microorganisms and improving water quality, but it does not leave a residual disinfectant in the water. UV light works by disrupting the DNA of microorganisms, rendering them unable to reproduce and cause illness, and is effective for disinfection without adding any chemical residuals.

Understanding these distinctions is crucial in water treatment processes, as choosing the appropriate disinfectant impacts the efficacy of treatment and the safety of the drinking water supply.