Abstract: A process and apparatus for removing organic and inorganic contaminants from solid media such as drill cuttings, tank bottoms or contaminated soils. The process is conducted in at least one thermal screw conveyor which provides two or more separate temperature zones which can be operated as one or more of low temperature thermal desorption, high temperature thermal desorption and pyrolysis. Preferably the process is conducted in three interconnected thermal screw conveyors which each provide a separate temperature zone. The process is conducted such that the solid media in each of the temperature zones is held under a vacuum. Direct and indirect heating of the solid media in each of the temperature zones is provided. In the pyrolysis zone, an organic binder may be added to encapsulate inorganic contaminants such as metals.