Thermal heating blanket in-situ thermal desorption for remediation of

Abstract

An in-situ thermal desorption system which combines thermal desorption and vacuum extraction to separate organic compounds from in place contaminated soils is disclosed. A 'heating blanket' desorption unit is applied directly to the surface of the hydrocarbon contaminated soil. The heating blanket assembly comprises of four basic components: a surface heating element, a thermal insulating mat, a vacuum collection system, and a vapor barrier. The surface heater, when energized, initiates a thermal front which moves down through the soil by thermal diffusion. As the soil is heated, organic compounds and water vapor are desorbed and removed from the soil matrix. A vapor collection system including a blower is fitted to the vapor barrier to establish a slight negative pressure inside the modular heating blanket units. The vacuum created by the in-line blower in the collection system sweeps clean air through and/or from the heat treated soil which purges volatile organic compounds (VOC), water, and other gases from the soil pores and sweeps in air from surrounding soils which is used to oxidize organics in the influent, within the heating elements, and within a thermal oxidizer. The off-gas is contained by the vapor barrier and collected via the blower. Air pollution control equipment is used to treat the off-gas, as necessary, to satisfy air emissions requirements.