In-situ remediation and vitrification of contaminated soils, deposits and buried materials
A method is disclosed in which a plasma arc torch is used to vitrify and remediate a site containing contaminated soils, resulting from a hazardous material deposit or spill, or contaminated buried objects. The contaminated earthen material or subterranean deposit is pyrolyzed, melted or solidified by the plasma torch which is energized at the bottom of a cased, vertical borehole, and then gradually raised to the surface. An array of boreholes, appropriately spaced, will remediate an entire mass of contaminated material. Similarly, burled objects such as metal drums containing contaminants and underground storage tanks may be selectively remediated at their specific buried depth. Similar use is made of the plasma torch in a second embodiment with the additional step of processing at selected underground locations in the borehole array to create a sealed horizontal layer, vertical cutoff walls or a sealed basin as a barrier against further leaching of contaminants into surrounding soil and groundwater. Gaseous by-products of the pyrolysis process are collected, treated and processed, as appropriate.
Claims
2. The method for in-situ remediation and vitrification of hazardous waste contaminated soil as claimed in claim 1 in which said borehole is formed to a depth greater than the depth of said contaminated soil.
4. The method for in-situ remediation and vitrification of hazardous waste contaminated soil as claimed in claim 3 further comprising gradually raising said torch in said borehole so as to melt sequentially higher portions of contaminated soil.
5. The method for in-situ remediation and vitrification of hazardous waste contaminated soil as claimed in claim 3 in which said plasma arc torch operates to melt a portion of contaminated soil only at the lowest depth to which the borehole is formed and is then removed from said borehole, and such process is repeated in each of the plurality of boreholes so as to form a coalesced and non-porous horizontal sealant layer to prevent further vertical leaching of contaminants to surrounding soil and aquifers.
6. The method for in-situ remediation and vitrification of hazardous waste contaminated soil as claimed in claim 1 wherein said borehole is formed as an initial hole and further comprising lowering, operating, and raising said torch so as to determine from said initial hole the effective diameter of said decontaminated and vitrified soil and thereby to determine the distance required between said initial hole and a remaining plurality of holes in order to completely vitrify and remediate an area containing said hazardous waste contaminated soil.
7. The method for in-situ remediation and vitrification of hazardous waste contaminated soil as claimed in claim 6 further comprising forming a plurality of boreholes each at a distance from adjacent boreholes so that the peripheral diameters of solidified materials as determined from the initial hole will coalesce and form a solidified mass throughout the area containing said hazardous waste contaminated soil.
8. The method for in-situ remediation and vitrification of hazardous waste contaminated soil as claimed in claim 7 further including the step of positioning said plurality of boreholes in such relative proximity so that the heat transmitted from said plasma torch through said contaminated soil beyond the portion being melted creates peripheral zones of solidified brick-like material and deplasticized material and the outer deplasticized material of each hole is coalesced with the respective deplasticized material formed around adjacent boreholes.
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- Technical Paper entitled: "An Innovative Process For The In-Situ Waste Destruction And Vitrification Of Buried Hazardous And Mixed Wastes". Examiner's Statement of Reasons for Allowance from the official file of the '795 patent. Official Action dated Apr. 2, 1992 from the prosecution history of the '797 patent. Letter sent by Reissue Applicant's patent counsel to the co-authors of the Spectrum '94 technical paper. Response to letter sent by Reissue Applicants' patent counsel on behalf of co-author J. K. Wittle. Declaration of Salvador L. Camacho.
Type: Grant
Filed: Dec 19, 1994
Date of Patent: Jan 13, 1998
Inventors: Louis J. Circeo, Jr. (Atlanta, GA), Salvador L. Camacho (Raleigh, NC)
Primary Examiner: Dennis L. Taylor
Law Firm: Olive & Olive
Application Number: 8/359,039
International Classification: A62D 300; E02D 1914; B09B 100;
