Abstract: A centrifugal pump has an open impeller with vanes having cutting edges at both the intake side of the pump bowl and the closed side of the bowl. The cutting edges of the vanes cooperate with narrow anvil ribs projecting inward from both sides of the pump bowl such that solid matter in the material being pumped is sliced and chopped inside the bowl. In addition, the intake end plate of the pump has an outer depression or recess with raised anvil ribs extending externally outward and cooperating with an additional external cutter received in the recess.