Chemical oxidation increases the oxidation state of a contaminant and decreases the oxidation state of the reactant. The electrons lost by the contaminant are gained by the oxidizing agent. The following equation is an example of oxidation reaction:

Figure 11.15.10 details the process flow for a chemical oxidation system. The main component is the process reactor. Oxidant is fed into the mixing unit (1), then the reactor (2). Reaction products and excess oxidant are scrubbed before venting to the ambient air. Reactor pH and temperature are controlled to ensure completion at the reaction. The reaction can be enhanced by adding UV light.

Systems that combine ozone with hydrogen peroxide or UV radiation are catalytic ozonation processes. They accelerate ozone decomposition, increasing hydroxyl radical concentration, and promoting oxidation of the compounds. Specifically, hydrogen peroxide, hydrogen ion, and UV radiation have been found to initiate ozone decomposition and accelerate oxidation of refractory organ-ics via free radical reaction. Reaction times can be 100 to 1000 times faster in the presence of UV light. Minimal emissions result from the UV-enhanced system.

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