Abstract: A submersible device for pumping liquids and liquid slurries and for concurrently grinding and comminuting solid and semi-solid material contained in the liquid product to be pumped. The device is generally located in a reservoir containing the liquid product, the reservoir being, for example, a sewage collection tank in a positive pressure sewage system. The liquid product is initially shredded by a cutter bar and then drawn upwardly through a grinding and comminuting section where an abrasive drum mounted on a rotary drive shaft cooperates with an interior cylindrical stator surface to grind and comminute solids and semi-solids contained in the liquid product. From the grinding section, the resulting slurry is drawn into a centrifugal pump section with an impeller having a frusto-conical pumping face formed with symmetrical pumping cavities that are operable in both directions of rotation.