A chemical or physical process that kills or inactivates microorganisms such as bacteria, viruses, and protozoa.
Source:
US EPA
US EPA Drinking Water
Glossary
Common water disinfectants include chlorine, chloramine, ozone and ultraviolet light.
Chloramination - Chloramine(s) - Chlorine - Ozone
GreenFacts Summary on Water Disinfectants & disinfectant by-products:
Español: Desinfectante
Français: Désinfectant(s)