Which method is most commonly used for disinfection in water treatment?

Chlorine is the most commonly used method for disinfection in water treatment due to its effectiveness, availability, and cost efficiency. Chlorine works by killing or inactivating harmful microorganisms, including bacteria and viruses, that can be present in water. Its widespread use has been established for over a century, making it a standard practice in municipal water treatment facilities.

Chlorine not only disinfects water but also provides a residual effect, meaning that it continues to act against pathogens throughout the distribution system, which helps to ensure the water remains safe to drink as it travels from treatment plants to consumers. The ease of application and ability to maintain a stable residual concentration further solidify chlorine's position as the preferred method for disinfection in water treatment processes.

In contrast, while ozone treatment is effective, it is less commonly used due to its high cost and the complexity involved in its implementation. Ultraviolet light is also a viable disinfection method but is mainly used in specific situations and does not provide long-lasting residual protection in the water system. Filtration is primarily a physical removal process and does not specifically target the inactivation of microorganisms, making it less suited for disinfection compared to methods like chlorine.