Apparatus and method for low temperature thermal stripping of volatile organic compounds from soil and waste materials with non-oxidative cross-sweep gases

A method of decontaminating materials containing organic compounds comprising:

• a) transporting the material to a substantially sealed container;
• b) placing the material in the container and conveying the material, under substantially sealed conditions, to a first heated vapor stripping conveyor;
• c) conveying the material under sealed conditions along the first vapor stripping conveyor to heat the material and cause moisture in the material and the compounds to be stripped from the material;
• d) streaming non-oxidizing gases at a controlled temperature across the material, from one side of the vapor stripping conveyor to the other side, to carry the organic compounds and moisture away from the material;
• e) conveying the material under substantially sealed conditions into and through a second heated vapor stripping conveyor positioned downstream of the first vapor stripping conveyor to maintain the material at a desired temperature to cause remaining moisture and contaminants, if any, to be stripped from the material;
• and
• f) maintaining the rate of flow and temperature of the gases to prevent undue surface drying of the material in the first vapor stripping conveyor and to maintain a less than atmospheric pressure in the second vapor stripping conveyor.

Apparatus for removing organic contaminants from contaminated materials comprising:

• a) a hopper;
• b) means for sealing the hopper from atmospheric air;
• c) a heated vapor stripping conveyor sealed from atmospheric air to vapor strip the contaminants from the material;
• d) means for conveying material in sealed condition from the hopper to the vapor stripping conveyor;
• e) means for supplying non-oxidative gases at a controlled temperature to the vapor stripping conveyor;
• f) means for introducing the non-oxidative gases into the vapor stripping conveyor;
• g) means for removing the non-oxidative gases from the conveyor and located to cause the non-oxidative gases to cross-currently sweep over the material to convey contaminants and moisture stripped from the material out of the vapor stripping conveyor;
• h) means for controlling the flow rate and temperature of the non-oxidative gases as they flow through the vapor stripping conveyor and to prevent undue surface drying of the material as the material passes through the vapor stripping conveyor.