PURPOSE: To provide a method and device for extremely decreasing the amt. of residues by removing water of the volume much more than in the case of compressing from fine pieces of animals and plants, such as waste vegetable and waste meat, generated in kitchens, food plants, farms, gardens, etc., with a small equipment investment.

CONSTITUTION: The fine pieces of animals and plants, such as waste vegetable and waste meat, are put into a pressure vessel and this vessel is hermetically closed. These fine pieces are then heated and pressured at 144 to 175°C and under a gage pressure of 3 to 8kg/cm2 in a wet state and is thereby subjected to a steaming and boiling for ≥5 minutes. The treated fine pieces are then discharged rapidly under the atm. pressure from the pressure vessel to allow the water content in the tissues of the animals and plants to evaporate and explode instantaneously, by which the fine pieces of the animals and plants are crushed and the water content therein is removed as steam.