Apparatus and method for hydrolyzing biological material for safe disposal thereof without the necessity of incineration or use of disinfectants are described. An alkaline solution having a concentration and an amount effective for hydrolyzing the biological material is brought into contact therewith by means of rotating paddles which both pound the biological material into small pieces and thoroughly mix the alkaline solution with the material under pressure and at elevated temperature. Following the hydrolysis of the biological material, a chosen portion of the water is removed from the alkaline solution and from the liquefied biological material, such that the resulting product solidifies when cooled. The present safe disposal of the biological material does not require incineration thereof, the addition of disinfectants thereto, or the discharge of liquid effluent containing processed biological material into the sewage system.