An apparatus and procedure for efficiently sterilizing waste material or products. The apparatus includes a reactor in the form of a cylindrical container housing two cylindrical tubes, a larger first tube and a smaller second tube. A first helical blade extends inwardly from the inner surface of the second tube, and a second helical blade bridges the outer surface of the second tube to the inner surface of the first tube. As the set of tubes is rotated in unison, material flows in one direction within the second tube and in the opposite direction in the space between the tubes. This axially compact design allows non stop introduction and extraction of waste, efficient use of heat energy, provided by steam injected into the reactor through a steam port, and allows for material to be input into and extracted from the device both at one end of the reactor.
