Like chlorine, ozone is a strong oxidizing agent. The ozonation (or ozonization) of compounds in water is a complex process. The mechanisms are very complicated, the parameters are many, but the possibilities of developing cost-effective treatment schemes for drinking water and waste water are large.

The ozonation can be applied as an alternative way of water purification capable of being used instead of conventional chlorination, in combination with chlorine, hydrogen peroxide and other oxidizing agents, as well as together with ultra-violet irradiation, ultrasound, sand, adsorption and on-exchange filtration. It is becoming traditional to use ozone at the end of process. For effective disinfection to be possible ozone concentration should be brought to 0.4-1mg/l and sustained like this within 4 minutes (Chichirova 1999). Thanks to its floculating effect ozone can be used for water pretreatment for converting permeates into colloidal form with subsequent precipitation on filters.

The advantage of ozonization is in the fact that ozone, besides being disinfectant, is able to discolor, eliminate the smells and flavors of water and, in general, make it more tasty. Ozone does not change natural properties of water. Ozone came into use as a disinfectant of potable water earlier, than chlorine. But it has not found the same wide application for water treatment techniques in developing countries because of shortage of electric power, as well as because chemical and physical properties of ozone aqueous solution are not sufficiently known yet.