Ozonation

Ozonation is a treatment process that uses ozone (O3) as a powerful oxidant and antimicrobial agent in water, air, and on surfaces. Ozone is a triatomic form of oxygen with strong reactivity and a relatively short lifespan in the environment, decomposing to diatomic oxygen over time.

Ozone is produced on site, since it is unstable and cannot be stored safely. It is generated by electrical discharge (corona discharge) or by ultraviolet irradiation of oxygen or air. The generated ozone is then dissolved in water or introduced into air where it acts as an oxidant or disinfectant; residual ozone must be managed with off-gas destruction or quenching.

In water treatment, ozonation can disintegrate color and odor, oxidize taste-and-odor compounds, and inactivate many microorganisms. It also oxidizes emerging contaminants and certain inorganic species. However, its effectiveness against some protozoa and other pathogens can be limited and may require longer contact times or subsequent disinfection. Ozonation can form disinfection byproducts, such as bromate in waters containing bromide, and oxidation byproducts like aldehydes or carboxylic acids. Residual ozone should be removed before distribution, or treated as needed.

In air and surface applications, ozone is used for deodorization, disinfection, and odor control, but it poses health hazards to humans at typical exposure levels, so treatment areas must be properly ventilated and ozone concentrations strictly controlled.

Compared with chlorination, ozonation reduces reliance on halogenated byproducts but requires on-site generation, energy input, and management of oxidation byproducts and residual ozone. Standards and practice depend on local regulations and the intended application.