NOVELTY - A digester (1) comprising a cylindrical rotatable drum (2) having a raw material inlet and a treated material outlet; a baffle plate (10) mounted within the drum between the inlet and the outlet for controlling the flow of material through the drum between inlet and the outlet, where each baffle plate is secured to the drum by attachment element such as space-apart radial rods (15) which extend outwardly from the baffle plate through a side wall (12) of the drum, is new.    USE - For the treatment of waste material such as municipal waste including organic waste material and converting the organic waste material into a bio-fuel or compost.    ADVANTAGE - The baffle mounting arrangement of the digester protects all welded joints against any corrosive environment within the digester drum. The support ring gives added reinforcement to the drum at each baffle mounting location. The cylindrical drum is protected internally by longitudinal stress bars fixed to inside face of the drum and extending along the length of the drum, each of the stress bars projecting inwardly from the inside face of the drum. Channels formed between these stress bars fill with organic material when the drum is in use and greatly enhance the impact absorption as well as provide the biological medium required to accelerate the fermentation process of the organic material. The damage to the baffle plate during operation of the drum is prevented, as the baffle plate is protected by sacrificial material.    DETAILED DESCRIPTION - A digester (1) comprises a cylindrical rotatable drum (2) having a raw material inlet and a treated material outlet; a baffle plate (10) mounted within the drum between the inlet and the outlet for controlling the flow of material through the drum between inlet and the outlet, where each baffle plate is secured to the drum by attachment element such as space-apart radial rods (15) which extend outwardly from the baffle plate through a side wall (12) of the drum. Each baffle plate has an opening or port (14) for through passage of material that is located off-center in the baffle plate. The opening/port has an elliptical shape. The drum has a support ring (16) extending around the drum in alignment with each baffle plate within the drum. Each face of baffle plate is coated with the corrosion resistant material such as an epoxy resin. The faces of baffle plate are protected by a sacrificial material, such as a hardwood, plastic, and other shock and corrosion resistant material.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic cross sectional illustration of the digester.    Digester (1)    Drum (2)    Baffle plate (10)    Side wall of the drum (12)    Port (14)    Spaced-apart radial rods (15)    Support ring. (16)