NOVELTY - Treating municipal solid waste, comprises: (a) feeding waste material into a pressure vessel; (b) closing the vessel and optionally evacuating the contents of air; (c) agitating the vessel while having steam pressure in the vessel at 2.5-4.8 bar (abs) and at 127-148 degrees C for at least 15 minutes; (d) reducing the pressure in the vessel; (e) optionally evacuating the contents of the vessel to 0.6 bar or lower; (f) discharging the vessel; and (g) classifying the treated waste.    USE - The process is useful for treating municipal solid waste, and providing green electricity (claimed). The fibrous fraction obtained from the process is also useful in a biomass combustion, gasification or pyrolysis process, as organic feed stock for aerobic digestion (biological conversion of microorganisms), or as filler for medium density fiberboard panels.    ADVANTAGE - The process of treating municipal solid waste requires shorter cycle time. In the process: vapors displaced contain extremely small concentrations of volatile organic compounds, odors, no steam or very less steam is released; only a very less affluent water has to be treated at the end of the process; and the fibrous fractions contain relatively low amounts of heavy metal and do not contain any inorganic particles.    DETAILED DESCRIPTION - Treating municipal solid waste, comprises: (a) feeding waste material into a pressure vessel; (b) closing the vessel and optionally evacuating the contents of air; (c) agitating the vessel while having steam pressure in the vessel at 2.5-4.8 bar and at 127-148 degrees C for at least 15 minutes; (d) reducing the pressure in the vessel; (e) optionally evacuating the contents of the vessel to 0.6 bar or lower; (f) discharging the vessel; and (g) classifying the treated waste. After step (b) steam at 165 degrees C or more and a pressure of 5 bar or more is injected into the vessel after closing to raise the pressure within the vessel to 2.5-4.8 bar in a condensing atmosphere, and therefore in the step (c) preferably, for a suitable period continue to inject steam at a reduced flow rate to allow heating of the waste material by steam condensation to maintain the waste treatment conditions. INDEPENDENT CLAIMS are also included for:    (1) a process to treat municipal solid waste, comprising heating the content of the vessel through indirect heating with thermal fluid;    (2) an integrated power plant and a waste treatment plant, where the waste treatment plant is able to perform the process and the heating requirement is provided by the steam supply of the power plant; and    (3) a method for providing green electricity by operating a power plant on site of a municipal solid waste treating plant able to perform the process, and providing about 5% or more of the energy requirement of the power plant by using the fibrous fraction, which has about 2 wt.% or less of inorganic material and plastic material respectively.    DESCRIPTION OF DRAWING(S) - The figure illustrates a general outline of a waste plant using an autoclave with the addition of high pressure steam in the initial phase of the process.    Feed conveyor (4)    Autoclave vessel (6)    Screening device (10)    Air classifier (12)    Hopper (14)