Abstract: An upright tank has an upper loading opening with a first horizontal wall therein spaced downwardly from the top. The horizontal wall has a central opening and an inverted frusto-conical guide extends upwardly for guiding material to be treated toward the opening. The upper portion of the tank has a fluid inlet. A horizontally operating cutter blade is disposed adjacent the opening in the horizontal wall, and such cutter blade initially cuts and shreds material received down the guide for producing a slurry. A second horizontal wall is disposed below the first wall to form a compartment therebetween and a cutter-impeller assembly is provided in this compartment to receive the slurry from the cutter blade and further reduce the material and mix it with fluid from the fluid inlet to provide a resulting readily flowable slurry. A driven shaft operates the cutter blade and cutter-impeller assembly and an outlet is radially disposed through which the slurry is discharged.