an apparatus for the pulping of waste material is disclosed including a tank , an impeller , a slurry chamber , and a discharge pipe for removal of slurry from the chamber . a flow directing device is provided within the chamber for increasing the flow into the discharge pipe . the device is appropriately positioned and shaped so that it will deflect the slurry from its rotational flow in the chamber to the discharge pipe . if the impeller is positioned horizontally at the bottom of the tank , it is preferably positioned off - center so waste material will not directly impinge upon the cutting surfaces when added to the tank . if the impeller is vertically oriented , the tank may be mounted on shock absorbers or resilient legs to minimize vibration .