Which common chemical is used for disinfection in water treatment?

Chlorine is widely recognized as a common chemical used for disinfection in water treatment due to its effectiveness in killing bacteria, viruses, and other pathogens. When added to water, it forms various compounds that maintain a residual disinfectant level, ensuring that water remains pathogen-free throughout the distribution system. Chlorine is favored for its cost-effectiveness, ease of use, and ability to provide a residual effect that protects water quality even after treatment.

Other disinfectants, while effective in certain contexts, do not match chlorine's widespread application in municipal water systems. For instance, ozone is a powerful oxidant used for disinfection, but it decomposes quickly and does not provide a lasting residual in treated water. Hydrogen peroxide is also used in some water treatment applications and can be effective against certain microorganisms but lacks the robust, long-lasting protection that chlorine offers in routine water treatment. Fluoride, primarily used to prevent tooth decay, is not utilized for disinfection purposes in water treatment.

In summary, the attributes of chlorine—combined with its established protocol in water treatment facilities—demonstrate why it is the prevalent choice for disinfection in public water supplies.