Abstract: An advancing freeze front is established in a porous region adjacent to or within contaminated earth. A flow of contaminated liquid phase water migrates toward the freeze front and a concentration of impurities is established in front of the advancing freeze front. When the freeze front reaches a collection zone, at least a portion is melted and the resultant water bearing concentrated impurities is collected and removed. This process may be repetitively performed. A liquid convection flow can be established transverse to the direction of freeze-front advancement to stabilize the solid/liquid interface at the freeze-front.

Abstract: An advancing freeze front is established in a porous region adjacent to or within contaminated earth. A flow of contaminated liquid phase water migrates toward the freeze front and a concentration of impurities is established in front of the advancing freeze front. When the freeze front reaches a collection zone, at least a portion is melted and the resultant water bearing concentrated impurities is collected and removed. This process may be repetitively performed.

Abstract: A method of making a nonporous, substantially liquid-impermeable cryogenic barrier within the Earth, and a nonporuous, substantially liquid-impermeable cryogenic barrier. A triple array of casings extends along respective sets of central axes from arrays of spaced apart locations on the surface of the Earth. A refrigerant is flowed through the two outer arrays of casings to form overlapping, continuous cold columnar regions extending along and about the respective central axes of the casings. The intermediate region between the two outer arrays of casings contains the central array of casings. A heat transtar agent is flowed through a selected subset of casings within the central array of casings to establish a relatively warm region between the continuous cold regions.

Abstract: An advancing freeze front is established in a porous region adjacent to or within contaminated earth. A flow of contaminated liquid phase water migrates toward the freeze front and a concentration of impurities is established in front of the advancing freeze front. When the freeze front reaches a collection zone, at least a portion is melted and the resultant water bearing concentrated impurities is collected and removed. This process may be repetitively performed.