Methane fermentation treatment method and treatment device comprising a fermentation tank, a waste tank, a generator, and a heater

A device for generating methane gas from organic wastes. A treatment device provided with a waste tank (2) into which wastes are introduced, a fermentation tank (1) that generates methane gas, a generator (3) that operates by using the methane gas, and a heater (4) that utilizes circulation of warm water (15) heated by waste heat generated during the operation of the generator (3) to heat an organic waste solution (9), flowing through a circulation path (11), to a predetermined temperature; wherein the circulation path (11) having an inflow port (17) is provided, which is communicated with an outflow port (10) arranged at a lower end of the fermentation tank (1) and above a liquid surface (12) of the organic waste solution (9) in the fermentation tank.