A method and apparatus for producing a useful soil product from contaminated soil and sludge is disclosed, and wherein the contaminated soil is heated in a primary treatment unit to a temperature above the vaporization temperature but below the auto ignition temperature of the contaminates, so as to volatilize the contaminates. The volatilized contaminates are then delivered to a secondary treatment unit where they are heated to a temperature sufficient to be converted to non-toxic products, such as carbon dioxide and water. The hot purified soil produced in the primary treatment unit is conveyed to a mixing chamber, and sedimentary sludge is also conveyed to the mixing chamber, and during mixing, heat energy is transferred to the sludge so as to heat and substantially sterilize the sludge, and to thereby produce a useful soil product.
