Which disinfection method uses ozone for disinfection?

• A. Ozone
• B. Heat
• C. Radiation
• D. Chlorination

Answer: (A)

Ozone disinfection relies on the strong oxidizing power of ozone to inactivate microorganisms. Ozone is generated on-site and dissolved into the water, where it rapidly oxidizes cellular components and genetic material, effectively killing or inactivating bacteria, viruses, and some protozoa. Because ozone decomposes quickly to oxygen, it doesn’t leave a long-lasting residual disinfectant in the water, unlike chlorine-based methods, which is an important practical consideration in distribution systems.

This approach is distinct from heat, which uses high temperatures to denature proteins; radiation, which employs UV or ionizing radiation to inactivate microbes; and chlorination, which uses chlorine compounds as the disinfectant.