The disclosed solid waste pump is a chopper pump, and preferably a chopper pump having a small rated motor and a semi-open impeller design. Particularly, a chopper pump having an impeller, at least one pump-out vane, an end plate, and a back plate including at least one cutting rib is disclosed. The impeller includes a back shroud and cutting vanes sharpened on a first edge extending opposite the back shroud and fixed on a first surface of the back shroud. The at least one pump-out vane is preferably fixed to a second surface of the back shroud opposite the first surface, while the end plate includes a surface adjacent to and facing the first edge of the cutting vanes and at least one internal cutting rib fixed to the end plate surface for shearing operation in combination with the sharpened edge of the cutting vanes of the impeller. Finally, the back plate has a surface adjacent to and facing the at least one pump-out vane and at least one cutting rib attached to the back plate surface for shearing operation in combination with the at least one pump-out vane.