NOVELTY - The apparatus for treating municipal solid wastes to produce a biomass product, comprises means for subjecting the waste to a pressurized steam flow, a first detachable door for loading the waste into a cylindrical vessel and for sealing a loading doorway under pressure, a second detachable door for unloading the biomass product from the vessel having a diameter of 1.8-3.65 m and for sealing a discharge doorway under pressure, and a helical flighting affixed to an interior wall of the vessel for mixing and agitating the solid waste or the biomass product and for conveying the solid waste.    USE - The apparatus is useful for treating municipal solid wastes such as food-, yard-, textiles-, plastics-, metals- and glass wastes, and to facilitate the separation and recovery of pulp and paper material from constituent non-biomass components and to produce a homogenous cellulosic biomass product.    ADVANTAGE - The apparatus is capable of effectively, easily, environmental safely and economically treating municipal solid wastes, producing a homogenous cellulosic biomass product and recovering the pulp and paper material from constituent non-biomass components.    DETAILED DESCRIPTION - The apparatus for treating municipal solid wastes e.g. food wastes to produce a biomass product, comprises means for subjecting the waste to a pressurized steam flow, a first detachable door for loading the waste into a cylindrical vessel and for sealing a loading doorway under pressure, a second detachable door for unloading the biomass product from the vessel having a diameter of 1.8-3.65 m and for sealing a discharge doorway under pressure, a helical flighting affixed to an interior wall of the vessel for mixing and agitating the solid waste or the biomass product and for conveying the solid waste and the biomass product between the loading doorway having a diameter of 1.2-1.8 m and the discharge doorway having a diameter of 1.2-1.8 m when the vessel is rotated around a cylindrical axis, a conical reduction in diameter at end of the vessel terminated by the loading doorway or the discharge doorway, means having a smooth exterior surface for rotating the vessel on a drive mechanism without gear teeth and sprocket teeth, means for rotating the vessel around the cylindrical axis in a first direction while loading the solid waste to convey the solid waste away from the loading doorway, a steam exhaust port on the second detachable door, a stream exhaust valve port for coupling to a source of steam, a stream exhaust valve coupled to the exhaust valve port for introducing steam into the vessel via the exhaust port during the loading of the solid waste, a main steam supply conduit, two external secondary steam distribution conduits mounted outside the vessel, and a primary steam distribution conduits mounted on the first detachable door coupling the main steam supply conduit to the external secondary steam distribution conduits. The subjecting means has the loading doorway and the discharge doorway at opposite ends of the vessel. The means are mounted on the vessel perpendicular to the cylindrical axis and at a predetermined distance from the opposite ends to support the vessel. A number of holes are present in a drive tires (17) for dissipating heat from the vessel to reduce heat transfer from the vessel to the exterior surface of the drive tires. The secondary steam distribution conduits extend through the holes without interfering with the rotation of the vessel. The rotating means has a drive wheel (22) that supports and provides torque to the vessel from a surface that contacts the exterior surface of the drive tires, a gear reducer coupled to the drive shaft, an electric motor to the drive wheels, and a drive brake coupled to the drive shaft. The vessel rotates in the first direction while unloading the biomass product to convey the biomass product out of the vessel via the discharge doorway. The first and second detachable doors are completely removable from the vessel so that the vessel is rotated around the axis with the first and second detachable doors. The drive mechanism comprises means for maintaining the cylindrical vessel in a horizontal position without tilting the vessel while loading and unloading the vessel, means for rotating the vessel in a second direction to convey the solid waste toward the loading doorway, a drive base (23), a pair of bearings secured into and on either side of the drive base, a drive shaft (24) supported on the drive base by the pair of bearings, and means for rotating the drive shaft in the bearings. The contact surface is wider than the exterior surface of the drive tire to allow for thermal expansion of the vessel. The drive tire is constructed of a metal having a hardness that is greater than that of the contact surface of the drive wheel. The drive wheel is aligned axially parallel with the cylindrical axis. A rotary union on the second detachable door coupling the source of steam to the vessel via the steam exhaust port while the vessel is rotated in either rotational direction about its longitudinal axis (16). Internal steam sparging conduits are connected to the external secondary steam distribution conduits via penetrations through the vessel. A stationary steam source is coupled to the vessel by the main steam supply conduit. A steam pressure relief valve is coupled to the stationary steam source and the steam exhaust valve port. A manual steam pressure relief valve is present between the rotary union and the detachable door. Sparging conduit bypass is coupled to the internal steam sparging conduits. Sparging conduit bypass valves are coupled to the sparging conduit bypass. Clean out ports are coupled to the secondary steam distribution conduits and steam conduits to provide means for manual clean of debris. An exhaust strainer is mounted inside the steam exhaust port to prevent solids from passing through the steam exhaust port. A steam pressure regulator is coupled to the stationary steam source for maintaining steam pressure to the vessel within a predetermined range. A manual steam safety valve is coupled to the stationary steam source and the steam exhaust valve port for manually shutting off steam from the stationary steam source and the vessel respectively.    DESCRIPTION OF DRAWING(S) - The figure shows a side view of a drive mechanism for the vessel.    Longitudinal axis (16)    Drive tires (17)    Drive wheels (22)    Drive base (23)    Drive shaft. (24)