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INTRODUCTION <br /> The demand for a means of removing small amounts ( c 100 mg/l <br /> or 100 ppm) of a variety of toxic or persistent waterborne <br /> compounds has steadily increased in the past fifteen years. <br /> During the latter half of the 19801s, the "push" in a number of <br /> Jurisdictions has been to reduce the concentrations of many of <br /> these substances to the low or sub parts per billion (ppb) level. <br /> To meet this demand, a number of approaches (e.g. , air <br /> stripping, activated carbon, reverse osmosis) have been employed, <br /> with varying degrees of success, depending upon the nature of the <br /> problem. However, each of the above mentioned techniques has <br /> associated with it a secondary disposal problem, in that they do <br /> not destroy the waterborne contaminant but merely transfer the <br /> problem from one environmental medium to another. <br /> Early attempts to oxidize the waterborne contaminants "in <br /> situ" with oxidants such as ozone (03 ) , hydrogen peroxide (H202) , <br /> hyprochlorous acid (HOC1) or hypochlorite ion (OC1 ) have met <br /> with limited success because of the excessively long contact <br /> times or the prohibitively large amount of oxidant required to <br /> achieve the desired degree of decontamination. <br /> The capability of oxidizing waterborne contaminants "in situ" <br /> has improved dramatically during the past ten years , resulting in <br /> a major reduction in the contact times required along with a <br /> concurrent reduction in the costs involved. This dramatic <br /> improvement is the result of the enhanced oxidation process. <br /> -4- <br />