It is also important to note that in the presence of even small amounts of organic substances under of a strong oxidant (ozone) in the water formed compounds such as, for example, formaldehyde, which, like chloroform, high-risk material for the sanitary-toxicological basis of ozone toxic hazard chlorine. In Germany, in many places is the dismantling of facilities for water ozonation. The price for the equipment down. Large toxic side effects on humans and vegetation (as an example, in swimming pools, using ozonation, live plants stop growing and die). When ozonization no prolonged effect. Water storage is required dohlorirovanie. In this method increases the toxicity.

The presence in the original water pollutants such as pesticides, and ozone treatment increases by several times their toxicological indicators. When applying water after ozonation on the pipeline is re-infection from inside the any pipeline bacterial film. Ozonation with all of this is the most expensive method. The use of germicidal irradiation units of water with ultraviolet rays relates to methods for the reagentless water disinfection. The effect of disinfection decreases with increasing water turbidity. Due to the fact that the irradiation of water with ultraviolet rays has no "residual-effect", using this method is best combined with reagent means, for example, with the method of disinfection with sodium hypochlorite, water, imparting antibacterial properties. In the course of bactericidal (UV) installed in every 1500 – 2000 hours of burning need to change expensive germicidal lamps, which is a serious disadvantage. The use of ultraviolet disinfection systems for water yielded very interesting results.