Abstract: A thermal desorption apparatus for the vaporization of volatile organic compounds and other contaminants within solid and liquid materials, such as sand, gravel, soil, clay, and industrial sludge is disclosed. The apparatus includes a generally cylindrical kiln having a bellows seal located at an inlet port, an outlet port, a fire box, an after burner, a quench tube assembly, a water cyclone having a rotary cylinder and a recyclable water tank system and pump. The kiln also includes a sludge and liquid injection port for the processing of contaminated liquid materials, as well as a computer controlled regulating system and program for operation of the apparatus. The apparatus also includes an entry port screw auger and an exit port screw auger, as well as a series of stationary paddles affixed to the inside kiln walls.