The Process and Water Quality Specialists
Ozone is classified as an AOP because the ozonation process generates hydroxyl radicals and target compounds are oxidized both by the direct reaction with ozone and by reaction with hydroxyl radicals. The reaction with hydroxyl radicals is much more important because the rate constant for the reaction of the target compound with hydroxyl radicals is typically several orders of magnitude higher than the apparent rate constant for the reaction of the target compound with ozone. For some recalcitrant compounds, it is necessary to add hydrogen peroxide to increase the production of hydroxyl radicals, as discussed below.
In the Ozone/Hydrogen Peroxide (O3/H2O2) process, ozone reacts with hydrogen peroxide to generate hydroxyl radicals. The hydroxyl radicals in turn oxidize target organics. The O3/H2O2 process has been applied to full-scale facilities for the oxidation of taste and odor (T&O) compounds MIB and Geosmin during seasonal T&O episodes. Ozone processes have also been shown to effectively oxidize 1,4-dioxane, as well as pharmaceuticals and personal care products.