NOVELTY - The fermentation tank (100) has several rotating shafts (121-124) arranged horizontally and in parallel with respect to one another, at bottom face of casing (110). Several plates (140) are arranged between the rotating shafts so as to cover the bottom face of casing. The plates are adapted to receive the organic waste thrown into the casing via an insertion opening (111) at top face of casing. A control apparatus (130) is provided for controlling the rotation direction and rotation angle of rotating shafts.    USE - Fermentation tank of fermentation system (claimed) used for fermenting refuse such as organic waste.    ADVANTAGE - By arranging the plates between the rotating shafts set horizontally on the bottom face of the casing, the organic waste deposited on the plates can be scraped off by swiveling each plate and the fermented waste can be discharged at high speed.    DETAILED DESCRIPTION - The fermentation tank has several plates that are arranged to cover the bottom face of the casing. The plates are arranged so that a clearance gap for ventilation is formed between adjoining plates. A cone-shaped disc adapted to rotate in parallel to the bottom face is located under the insertion opening of casing. One or more guide elements are arranged in radial direction of the disc. A sensor for detecting the height of fermentation target object is provided inside the casing. The cone-shaped disc is vertically moved inside the casing according to the height of the fermentation target object. One or more hollow ventilation pipes are arranged between the opposing surfaces of the casing. A ventilation hole is formed in the peripheral surface of the hollow pipe. An INDEPENDENT CLAIM is included for fermentation system that includes a mixing unit for mixing fermentation target object and wood chips, and a separation unit for separating the wood chips from the fermented item discharged from the fermentation tank.    DESCRIPTION OF DRAWING(S) - The drawing shows the perspective view of the fermentation tank. (Drawing includes non-English language text)    Fermentation tank (100)    Casing (110)    Insertion opening (111)    Rotating shafts (121-124)    Control apparatus (130)    Plate (140)