In situ heating to detoxify organic-contaminated soils
AssigneeBattelle Memorial Institute
InventorsJames L. Buelt, Kenton H. Oma
Life of this patent
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Abstract
A method and apparatus for decontaminating ground areas where toxic chemicals are buried comprises disposition of a plurality of spaced electrodes in the ground to be treated and application of a voltage across the electrodes for bringing about current flow through the ground. Power delivered to the ground volatilizes the chemicals which are collected and directed to a gas treatment system. The preferred form of the invention employs high voltage arc discharge between the electrodes for heating a ground region to relatively high temperatures at relatively low power levels.
Claims12
The method of detoxifying waste sites and the like containing hazardous volatilizable material, said method comprising:
- inserting at least two electrodes through the soil surface into the ground proximate a said waste site and at spaced points from one another in substantially encompassing array to at least a portion of said waste site,
- heating a region of ground adjacent the soil surface and therebelow to a temperature below the melting temperature thereof, said temperature being greater than 100.degree. and less than 1200 .degree.C., for an extended period of time in order to volatilize said material by applying a voltage between a pair of said electrodes adjacent the soil surface spanning said region for causing a current flow through said ground region therebetween of a value less than would melt the soil, and
- collecting said material, as volatilized, above ground level.
The method of detoxifying waste sites and the like containing hazardous volatilizable material, said method comprising:
- inserting plural electrodes into the ground proximate a said waste site and at spaced points from one another,
- heating a region of ground to a temperature below the melting temperature thereof, said temperature being greater than 100.degree. and less than 1200.degree.C., for an extended period of time in order to volatilize said material by applying a voltage between a pair of said electrodes spanning said region for causing a current flow through said ground region therebetween,
- further including absorbing electrically conductive heavy oil substantially evenly in the ground region between said pair of electrodes before application of said voltage, and
- collecting said material as volatilized or pyrolyzed above ground level.
A method of detoxifying waste sites and the like containing hazardous volatilizable material, said method comprising:
- inserting plural electrodes into the ground proximate a said waste site and at spaced points from one another,
- heating a region of ground to a temperature below the melting temperature thereof, said temperature being greater than 100.degree. and less than 1200.degree.C., for an extended period of time in order to volatilize said material by applying a voltage between a pair of said electrodes spanning said region for causing a current flow through said ground region therebetween of a value less than would melt the soil,
- maintaining a partial vacuum with respect to the region of ground where the temperature is raised wherein said partial vacuum is maintained through said electrodes, and collecting said material as volatilized via said electrodes.
Dependencies are inferred from the claim text.