TECHNOLOGY FOCUS - ENVIRONMENT - Preferred Process: The temperature and the pressure inside the vessel are at greater than or equal to 133 degrees C and greater than or equal to 300 kPa. The time taken for waste to pass through the vessel is at least 20 minutes. (A) are shredded to give particles having grain size less than or equal to 20 mm. The waste is moved through the heated vessel by means of a conveyor (particularly a helical screw conveyor). The waste is homogenized prior to drying. The waste is homogenized in a pug mill. The treated waste is subsequently exposed to a process (particularly milling, crushing or rolling) to produce a flowable granular waste product with a bulk density of about 800 Kg/m3. The granular waste product has particle size less than or equal to 3 mm and is screened using a vibrating screen, where granular waste product with particle size greater than 3 mm is rejected and returned for re-processing.Preferred Components: (A) are animal by-products or food waste products and any packaging material. The waste is dried mechanically or in a drum dryer at less than or equal to 400 degrees C. The dried waste has a moisture content of about 10%. The high-pressure steam is passed through the body of the heated vessel. The fuel material derived from waste animal has calorific value of 18000-20000 kJ/kg and ash content of 4-5%.    TECHNOLOGY FOCUS - INSTRUMENTATION AND TESTING - Preferred Components: The heated vessel is a steam-jacketed vessel. The apparatus further comprises means for receiving waste products, means for homogenizing waste products, and means for screening crushed or milled waste products. EXAMPLE - A mixed waste comprising meat products (68 kg), bread (136 kg) and vegetable waste (22.8 kg) was passed through shredding apparatus, reducing the size of waste particles to less than 20 mm diameter. The waste was then dried in a drum dryer at 380 degrees C, reducing the moisture in the waste from 58% in the raw materials to 8%. The dried waste was discharged into a steam-heated vessel and carried along the length of the vessel on a screw conveyor. The temperature within the vessel was maintained at a minimum of 133 degrees C, the pressure maintained at greater than or equal to 300 kPa and waste passed through the vessel at such a rate that all waste remained at this temperature and pressure inside the vessel for at least 20 minutes. Treated waste was then milled to produce a granular powder having particle size of 2-3 mm and moisture content of 0.1%.