PURPOSE: To allow the sanitary and efficient fermentation treatment of org. waste without splashing malodors and stains to the ambient and without requiring the separate treatment of stained bags at the time of charging the org. waste, such as crude refuse, into a fermentation chamber.

CONSTITUTION: The org. waste is put into biodegradable plastic bags 30 having biodegradability and these biodegradable plastic bags 30 are put into the fermentation chamber provided with a crushing and agitating machine. While the biodegradable plastic bags are crushed by operating the crushing and agitating machine, the org. waste is agitated and the biodegradable plastic bags and the org. waste are fermented by microorganisms. The bags and org. waste are thus treated.