NOVELTY - A fermentation tank comprises bracket with ends provided with blocking plates (18,9). The bracket is provided with fermentation vessels (15,23,27) with each provided with screw (16,22,25), respectively. The right end of upper fermentation tank is provided with feeding port (11). The upper and middle fermentation vessels are connected by upper through pipe (19). The middle and lower fermentation vessels are connected by lower through pipe (32). The left end of lower fermentation vessel is provided with discharging port (26). The left blocking plate is provided with bacteria adding port (20).    USE - A fermentation tank is used for producing organic fertilizers from tobacco waste (claimed).    ADVANTAGE - The tank has good fermentation performance.    DETAILED DESCRIPTION - A fermentation tank comprises bracket with left and right ends respectively provided with left blocking plate (18) and right blocking plate (9). The bracket is provided with upper fermentation vessel (15), middle fermentation vessel (23) and lower fermentation vessel (27). The right end of upper fermentation tank is provided with feeding port (11). The upper fermentation vessel and middle fermentation vessel are connected by upper through pipe (19). The middle fermentation vessel and lower fermentation vessel are connected by lower through pipe (32). The left end of lower fermentation vessel is provided with discharging port (26). The middle fermentation vessel and lower fermentation vessel are cylindrical in structure. The upper fermentation vessel comprises material channel and heating vessel. The material channel is cylindrical in structure. The semicircular heating vessel is arranged below material channel. The heating vessel is provided with hot oil adding-heating device (12). The upper fermentation vessel is provided with upper screw (16). The middle fermentation vessel is provided with middle screw (22). The lower fermentation vessel is provided with lower screw (25). The screwing directions of upper screw and lower screw are identical. The screwing directions of upper screw and middle screw are opposite. The upper screw, middle screw and lower screw are connected with driving device. The left blocking plate is provided with bacteria adding port (20) connected to middle fermentation vessel.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic diagram of fermentation tank.    Blocking plate (9,18)    Feeding port (11)    Fermentation vessel (15,23,27)    Screw (16,22,25)    Upper through pipe (19)    Bacteria adding port (20)    Discharging port (26)    Lower through pipe (32)