Chlorine dioxide

ClO₂: Chlorine dioxide is a strong oxidizing agent that is added to water as a disinfectant and to control taste and odour. Chlorine dioxide rapidly decomposes into chlorite, chloride, and chlorate.

Source: WHO Guidelines for drinking water quality 

Chlorine dioxide does not occur naturally in the environment but is synthetically manufactured. It is used as a bleach at paper manufacturing plants and as a water disinfectant. Due to its high reactivity, chlorine dioxide released does not remain in the environment for a substantial period of time.

Chlorate - Chlorine - Chlorite - Disinfectant(s)

Español: Dióxido de Cloro
Français: Dioxyde de chlore

Water Disinfectants

Chlorine Sodium Hypochlorite