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URS. I iELH77rGAL B LLE i IIV # v.-/ Oxygen Release Compound, ORC® Quantitative Guidelines for Soil Remediation Applications (Biopiles) If the qualitative need to use ORC has been established there are several ways to calculate use rates. One must know the weight of soil either by direct measurement or by soil type estimate. Since ORC is most appropriate for heavy clay soils a value of 3000 lbs/cubic yard will be used in this example. Under these conditions one would need 3 lbs. of ORC for every .1% of ORC applied on a wt./wt. basis, noting that ORC is 8% oxygen by weight. Calculation of the hydrocarbons that can be remediated from the oxygen applied through ORC is not straightforward; unexpectedly high results have been noted in field tests. Given a straight calculation based on the standard 3:1 ratio, 3 pounds or 1362 grams of ORC with 8% oxygen, would be able to remediate 36 grams of hydrocarbons. This would be enough to remediate 27 parts per million (ppm) of hydrocarbon in a cubic yard of the soil as described. If the ratio approached 1:1, which more realistically includes some biological incorporation of carbon in addition to mineralization to carbon dioxide, there would be a capacity to remediate about 80 ppm of hydrocarbon for every .1% of ORC used on a wt./wt. basis. In a test of ORC on the remediation of weathered crude oil, about 7000 ppm of hydrocarbon was remediated in 200 days (1 application) with 1% ORC. By the above calculations, even under the best of conditions (1:1 ratio), only 800 ppm should have been remediated. One of the reasons the higher remediation rate may have occurred is related to the physical nature of ORC. Because it is a very fine insoluble particle it has the capability of being intimately mixed throughout a tight soil mass. The result is that one has countless micron-sized particles releasing oxygen simultaneously effecting a mass transfer phenomenon for oxygen that is not possible with forced air. This generates the observed "yeast effect," in which the pile expands. What may be happening is that numerous microchannels are being created such that ambient air can more readily permeate the pile. It must be noted that even though a volume of ambient air entered the system upon mixing, the experiments were done under saturated conditions to effect an anaerobic environment. With the extant oxygen being flushed out, the remediation effects could have been due to a combination of ORC and the facilitated diffusion of ambient oxygen as mediated by the ORC induced yeast effect. Practically speaking, under the right conditions ORC would best be used in the remediation of several thousand ppm of hydrocarbons, either initially in a low contamination situation, or as a polishing agent after basic forced air applications. Concentrations of hydrocarbons that make the soil oily would be hard to manage as the insoluble ORC particle can become obstructed by coating. At a cost of$9 per pound for ORC, a typical application of.5% ORC which is appropriate for about 3000 - 4000 ppm, would cost $135 per cubic yard in a 3000 lb/cu. yd. soil. REGENESIS personnel are available to assist you with a specific analysis of your needs. REG E N ES I S ----------------------------------------------------------------------------------------- Bioremediation Products 27130A Paseo Espada, Ste 1407, San Juan Capistrano, CA 92675 Phone: 714-443-3136 Fax: 714-443-3140