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Figure 1 <br /> OXYGEN RELEASE KINETICS OF ORC <br /> 20 <br /> L VT. Fw.N <br /> 1 g ................................................................................ <br /> 16 ............................................................................... <br /> 14 ................................................................................ <br /> 0,12 ..................................................................... <br /> yyy... .....�--......�........ <br /> 10 ....................... <br /> .....®„..._..m.,, :�.c:......................... _ <br /> ... <br /> g ....................m:::............... __.......... <br /> v 4 .... <br /> .:...........�..................................................... <br /> . <br /> 2 <br /> a 0 <br /> 0 50 100 150 200 250 300 350 400 <br /> Hours Since Inception <br /> � WVM ORC .5%wVwt ORC <br /> In field applications, longevity can be reduced by oxygen demand factors. Other <br /> conditions, such as temperature and pH play a role; acidic conditions promote a faster <br /> oxygen release and basic conditions slow it down. <br /> During the past three years, studies have been conducted at several recognized private <br /> laboratories and universities which proved that ORC could release oxygen slowly and that <br /> remediation of hydrocarbons could be causally linked to this property through enhanced <br /> microbial activity. Subsequent field applications in contaminated soil demonstrated that <br /> ORC was effective in promoting bioremediation under "real world" conditions. Having <br /> established the value of ORC in soil bioremediation, its applicability to groundwater <br /> remediation became a focal point of activity. <br /> ORC can be configured to form an oxygen barrier across a contaminated plume. A row <br /> of wells or a trench containing ORC can release oxygen slowly and cut off the plume by <br /> fostering bioremediation in the oxygenated zone. Oxygen barriers are a passive, in4tu <br /> treatment that can represent significant capital and maintenance cost advantages over <br /> alternative means of remediation. A properly placed and maintained oxygen barrier offers <br /> the assurance that the plume remains "out-off," and does not reappear as it can with other <br /> methods. <br /> The first field evaluations of oxygen barriers were made by the University of Waterloo and <br /> North Carolina State University (NCSU). The first limited commercial test application was <br /> recently completed by a major consulting firm in Alaska. At Waterloo, the contamination <br /> was created by measured addition to the groundwater at a widely studied site (Canadian <br /> Forces Base Borden). The Waterloo experiment used two of the BTEX components, <br /> benzene and toluene, whereas in the NCSU and Alaska projects the entire BTEX fraction <br /> was involved, since an actual fuel spill was the contaminant source. <br /> The Waterloo experiment has been completed and the results published as previously <br /> mentioned. The preliminary results of the NCSU experiment were presented at The <br /> Second International Symposium for In Situ and On Site Bioreclamation (1993 Battelle <br />