Abstract: In situ hydrous pyrolysis/oxidation process is useful for in situ degradation of hydrocarbon water and soil contaminants. Fuel hydrocarbons, chlorinated hydrocarbons, polycyclic aromatic hydrocarbons, petroleum distillates and other organic contaminants present in the soil and water are degraded by the process involving hydrous pyrolysis/oxidation into non-toxic products of the degradation. The process uses heat which is distributed through soils and water, optionally combined with oxygen and/or hydrocarbon degradation catalysts, and is particularly useful for remediation of solvent, fuel or other industrially contaminated sites.

Abstract: A method to simultaneously remediate mixed-waste underground contamination, such as organic liquids, metals, and radionuclides involves chemical tailoring of steam for underground injection. Gases or chemicals are injected into a high pressure steam flow being injected via one or more injection wells to contaminated soil located beyond a depth where excavation is possible. The injection of the steam with gases or chemicals mobilizes contaminants, such as metals and organics, as the steam pushes the waste through the ground toward an extraction well having subatmospheric pressure (vacuum). The steam and mobilized contaminants are drawn in a substantially horizontal direction to the extraction well and withdrawn to a treatment point above ground. The heat and boiling action of the front of the steam flow enhance the mobilizing effects of the chemical or gas additives.

Abstract: An electrode well for use in powerline-frequency heating of soils for decontamination of the soil. Heating of soils enables the removal of volatile organic compounds from soil when utilized in combination with vacuum extraction. A preferred embodiment of the electrode well utilizes a mild steel pipe as the current-carrying conductor to at least one stainless steel electrode surrounded by a conductive backfill material, preferably graphite or steel shot. A covering is also provided for electrically insulating the current-carrying pipe. One of the electrode wells is utilized with an extraction well which is under subatmospheric pressure to withdraw the volatile material, such as gasoline and trichioroethylene (TCE) as it is heated.

Abstract: A thermal barrier is disclosed for surface confinement with active cooling to control subsurface pressures during thermal remediation of shallow (5-20 feet) underground contaminants. If steam injection is used for underground heating, the actively cooled thermal barrier allows the steam to be injected into soil at pressures much higher (20-60 psi) than the confining strength of the soil, while preventing steam breakthrough. The rising steam is condensed to liquid water at the thermal barrier-ground surface interface. The rapid temperature drop forced by the thermal barrier drops the subsurface pressure to below atmospheric pressure. The steam and contaminant vapors are contained by the thermal blanket, which can be made of a variety of materials such as steel plates, concrete slabs, membranes, fabric bags, or rubber bladders.

Abstract: A dynamic underground stripping process removes localized underground volatile organic compounds from heterogeneous soils and rock in a relatively short time. This method uses steam injection and electrical resistance heating to heat the contaminated underground area to increase the vapor pressure of the contaminants, thus speeding the process of contaminant removal and making the removal more complete. The injected steam passes through the more permeable sediments, distilling the organic contaminants, which are pumped to the surface. Large electrical currents are also applied to the contaminated area, which heat the impermeable subsurface layers that the steam has not penetrated. The condensed and vaporized contaminants are withdrawn by liquid pumping and vacuum extraction. The steam injection and electrical heating steps are repeated as necessary.