FIG. 11.15.10 Process flow diagram for chemical oxidation system. (Reprinted from U.S. EPA, 1991.)
of heat. Waste composition must be well-known to prevent producing a more toxic or hazardous end product. Oxidation by hydrogen peroxide is not applicable for in situ treatment. However, it may be used for surface treatment of contaminated groundwater sludge. Oxidation is not cost-effective for highly concentrated waste because of the large amount of oxidizing agent required.
Ozone can be used to pretreat wastes to break down refractory organics or to oxidize untreated organics after biological or other treatment processes. Ozone is currently used to destroy cyanide and phenolic compounds. Rapid oxidation offers advantages over the slower alkaline chlorination method. Limitations include the physical form of the waste (i.e., sludges and solids are not readily treated) and non-selective competition with other species. Ozonation systems have higher capital costs because ozone generators must be used.
The cost of generating UV lights and the problems of scaling or coating on the lamps are two of the major drawbacks to UV-enhanced chemical oxidation systems. They do not perform well in turbid waters or slurries because reduced light transmission lowers the effectiveness.
Status. Commercially available.
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