NOVELTY - The reactor (10) has a cutting element (35) that is attached to a shaft (20) that is rotated at a predefined rate, such that the cutting element cuts through bridged or agglomerated material without mixing contents within vessel (15). The cutting element is attached in the perpendicular direction at a predefined angle with respect to arm (25) of the shaft. The arm is located at predefined distance from drive mechanism of the shaft.    USE - Plug flow anaerobic reactor used for producing methane.    ADVANTAGE - The suspended solids contained within the reactor is reduced and methane gas is produced efficiently from the reactor by using a simple technique.    DETAILED DESCRIPTION - The reactor has a cutting element that is attached to a shaft, such that the cutting element cuts through bridged or agglomerated material without mixing contents within vessel. A feed port (40) is formed on the top portion (70) of the vessel and effluent discharge port (45) is formed on the bottom portion (65) of the vessel. The bacteria from the bottom portion of the reactor is mixed with incoming feed material from the top of the vessel. The storage capacity of the vessel is in the range of 900000-1250000 gallons. INDEPENDENT CLAIMS are included for the following:    (1) method for producing methane from organic feed stock, which involves charging an organic material supplied into the top portion of vessel comprising a shaft that is rotated at a predefined rate. A cutting element is attached to the shaft. The shaft is rotated such that cutting element cuts through bridged or agglomerated material without mixing contents within the vessel. The organic material is anaerobically digested under mesophilic or thermophilic conditions to produce methane, while allowing the organic material to propagate through the vessel in the downward direction. The methane gas produced from the anaerobic digestion of the organic material is collected. The total amount of solid contained in the organic material is in the range of 20-50%. The rotating speed of the cutting element is in the range of 5-12 ft/min; and    (2) method for producing methane from plug flow anaerobic reactor.    DESCRIPTION OF DRAWING(S) - The drawing shows an explanatory view of the plug flow anaerobic reactor.    Plug flow anaerobic reactor (10)    Vessel (15)    Shaft (20)    Arm (25)    Cutting element (35)    Feed port (40)    Effluent discharge port (45)    Bottom portion of vessel (65)    Top portion of vessel (70)