TECHNOLOGY FOCUS - ENVIRONMENT - Preferred Method: The process (P2) to make organic fiber based fuel involves: the process (P1); and further involves (c') depressurizing the vessel, and applying vacuum to the vessel to dry the fibrous content of the vessel to water (40-60 wt.%); (d') classifying the treated waste through a screen to remove the 12 mm fraction comprising plastic (less than 2 w.%) (calculated on 60 wt.% moisture in the fibers); and (e') treating the 12 mm fraction in an air classification device to yield a fibrous fraction comprising inorganic material (less than 2 w.%) (calculated on 60 wt.% moisture in the fibers). The method (M1) for providing green electricity involves: operating a power plant on site of MSW treating plant (P'); and providing greater than or equal to 5% of the energy requirement of the power plant by using the fibrous fraction obtained by using the process (P1) or (P2) and having inorganic material ( less than or equal to 2 wt.%) and plastic material ( less than or equal to 2 wt.%). The processes (P1) and (P2) further involve (e2) classifying the treated waste through a screen to remove the less than or equal to 15 mm fraction comprising plastic (less than 5 wt.%) (calculated on 60 wt.% moisture in the fibers). The fluid used to clean the exhaust gas is process water, which is used in part to wet the waste which is fed to the vessel.    TECHNOLOGY FOCUS - INSTRUMENTATION AND TESTING - Preferred Process: In the process (P1), greater than or equal to 2 vessels are used in an alternating fashion, by using steam from the discharge step (c) to apply steam to another vessel, which involves (c1) depressurizing the vessel, transferring the steam from a first vessel to a second vessel with the aid of a compressor; and further involves (c2) heating the content of the vessel through indirect heating with thermal fluid, and (e1) classifying the treated waste, to yield several fractions, including a fibrous fraction, shattered glass and grit, and larger parts such as plastics and metals. The steam used for the direct steam injection (preferably more than 90%) is derived from another pressure vessel used to treat waste; the amount of energy supplied during normal operation through (fresh) boiler steam is ( less than or equal to 25, preferably less than or equal to 10)%; and no fresh steam is supplied to at least one vessel during normal operation. The average energy input is less than or equal to 125 kWh per tonne of waste. The thermal fluid is provided via a heating system comprising a primary circuit with a heating element for heating the thermal fluid, and secondary circuits (one circuit for each vessel) for heating the greater than or equal to 2 vessels independently. The indirect heating is applied through conduits in the vessel, and through a heated jacket of the vessel. The vessel is designed such that with respect to the energy supplied through indirect heating, (35-80%) of the energy can be transferred through the jacket, and (20-65%) of the energy can be transferred through the internal conduits. The conduits are assembled in such a way that they can act as baffles to stir the content of the vessel. The vessel is insulated on the outside of the vessel. A vacuum is applied after charging of the vessel but before adding steam to it. During the discharge of the vessel, the inner surface and the coils of the vessel are at less than or equal to 100 degrees C. The process for the treatment of municipal waste in an autoclave process is followed by classification of the treated materials, in which the open side of the conveyers and other open equipment in the classification section after autoclaving comprises a hood with air suction to catch dust and volatile material (when present) resulting in an air stream with contamination, in which the suction maintains a velocity in the inward air stream of greater than or equal to 0.1 m/second, and supplying the air stream to a washing or cleaning section; and/or in the classification step, the majority of the fiber product, contaminated with glass and grit particles is subjected to an air separation step on a vibrating screen, which causes the lighter particles to flow downward, and the heavier particles to move upwards. Preferred Components: The vacuum pump is an eccentric-rotary vacuum pump; and has a capacity sufficient to reach a vacuum of 0.5 bar (abs) in a vessel of greater than or equal to 10 m3 in less than or equal to 15 minutes. The exhaust gas is cleaned in a scrubber. The compressor is steam driven compressor. Preferred Apparatus: The apparatus (A) for treating municipal waste comprises: a feeding unit, an autoclave, a system to achieve a vacuum of greater than or equal to 0.8 bar (abs) comprising a scrubber and a rotary vacuum pump, and a classification section comprising a screen and an air classification device. In the apparatus, the pump is a liquid ring vacuum pump having a capacity of 1-30 m3/minute. The apparatus comprises a water tank with process water that can be used in the scrubber. The classification section in the apparatus comprises a screen, and an air classification device that is capable of treating fiber containing product, contaminated with glass and grit particles, and comprises a tilted vibrating screen and an air supply capable of creating an air flow from the bottom of the screen. The apparatus further comprises: at least two autoclaves; a connection between several autoclaves for transporting steam from one autoclave to another, which comprises a compressor; at least two autoclaves comprising internal conduits for transporting a thermal fluid, and/or a jacket with openings for transporting thermal fluid, the connection between the at least two autoclaves for transporting steam; and a heating system which comprises a primary circuit with a heating element for heating the thermal fluid, and secondary circuits (one circuit for each vessel) for heating the greater than or equal to 2 vessels independently. The secondary circuits comprise a cooling element. Preferred Plant: In the plant (P'1), a part of the waste treatment plant which receives the waste is kept under sub-atmospheric pressure; the air of that part of the building is vented through a bio-filter; and the remainder of the apparatus is provided with local extract ventilation (LEV) hoods to preclude significant contamination of the environment. The integrated power plant and waste treatment plant comprises: the waste treatment plant comprising the plant (P'), (P'1) or (P'2), in which the heating requirement in the waste treatment plant is provided by the steam supply of the power plant. EXAMPLE - No suitable example given.