Which chemical is widely used as an effective disinfectant in water treatment?

Chlorine is widely recognized as an effective disinfectant in water treatment due to its ability to kill a broad spectrum of pathogens, including bacteria, viruses, and protozoa. Its effectiveness stems from its strong oxidizing properties, which allow it to attack and destroy the cellular structure of microorganisms. Chlorine is also relatively cost-effective and easy to use, making it the standard choice for municipal water disinfection processes.

In addition, chlorine's residual properties ensure that some level remains in the water even after treatment, providing ongoing protection against recontamination as the water is distributed to consumers. This characteristic is crucial for maintaining water safety from the treatment plant to the tap.

While ozone is also a strong disinfectant and has advantages like potentially being more effective against certain pathogens without forming harmful byproducts, it lacks the residual effectiveness of chlorine, which can be a significant disadvantage in maintaining safe drinking water throughout the distribution system. Hydrogen peroxide, although utilized as a disinfectant in certain applications, is not as commonly used in large-scale water treatment due to its instability and higher costs. Fluoride is primarily added for dental health benefits and does not serve as a disinfectant.