METHOD OF REMOVING RESIDUE FROM STIRRER OF METHANE FERMENTATION TANK AND METHANE FERMENTATION TANK ALLOWING EASY REMOVAL OF RESIDUE FROM STIRRER

摘要

PROBLEM TO BE SOLVED: To provide a residue removal/prevention method which can remove residue entangled with a stirrer in a methane fermentation tank and a methane fermentation tank suitable for execution of such a residue removal method.SOLUTION: A rotation shaft of a stirrer is hollow, and an opening is provided in the vicinity of a connection part connected to a stirring blade in the rotation shaft. A covering member having a plurality of openings and a flat outer surface is attached so as to cover the connection part between the rotation shaft and the stirring blade. The stirrer is operated between normal operation and reverse rotation at constant time intervals. A medium for removal is supplied to the rotation shaft, passed through the opening of the rotation shaft and discharged from the openings of the covering member so as to remove residue entangled with the stirrer. The medium for removal is water, a to-be-treated liquid, digestion gas, nitrogen or carbon dioxide.