The Operating Principle of Peroxone (Ozone/Hydrogen Peroxide) Disinfection

Jun 13, 2022

The Operating Principle of Peroxone (Ozone/Hydrogen Peroxide) Disinfection

Hydroxyl radicals are produced during the spontaneous decomposition of ozone. By accelerating the ozone decomposition rate, the hydroxyl radical concentration is elevated, and therefore the oxidation rate of various compounds in the water is increased. Several methods have been used to increase ozone decomposition and produce high concentrations of hydroxyl radicals: ozone plus UV, ozone at high pH, hydrogen peroxide plus UV, and other combinations.  

Disinfection in a peroxone system occurs due to two reactions: (1) direct oxidation of compounds by aqueous ozone, and (2) oxidation of compounds by hydroxyl radicals produced by the decomposition of ozone.

The main difference between the ozone and peroxone processes is that the ozone process relies heavily on the direct oxidation of aqueous ozone while peroxone relies primarily on oxidation with hydroxyl radical. In the peroxone process, the ozone residual is short lived because the added peroxide greatly accelerates ozone decomposition. However, the increased oxidation achieved by the hydroxyl radical greatly outweighs the reduction in direct ozone oxidation. The net result is that oxidation is more reactive and much faster in the peroxone process compared to the ozone molecular process. The high reactivity of hydroxyl radicals creates a different effect in the reactions with water constituents and, thus, improves disinfection effectiveness.

Peroxone is one of the most potent and effective germicides used in water treatment. It is slightly more effective than ozone against bacteria, viruses, and protozoan cysts. It is effective in oxidizing difficult-to-treat organics, such as taste and odor compounds. Additional selected advantages of using peroxone as a disinfection method are: it has been shown to be effective in oxidizing halogenated compounds; it transforms organic carbon compounds to a more biodegradable form; pumps used to house peroxide are not very large, so space requirements are not significant; peroxone itself does not form halogenated DBPs.

The main drawback of this process is that peroxide is also a strong oxidant and contact with personnel is extremely dangerous. Hydrogen peroxide is a hazardous material requiring secondary containment for storage facilities.