Recessed impeller or vortex pump uses an impeller that is either partially or wholly recessed into the rear of the casing. The spinning action of the impeller creates a vortex or whirlpool. This whirlpool increases the velocity of the material being pumped and the velocity is then converted to increased pressure or head. Recessed impeller pumps are essential when slag needs to be transported. These pumps are ideal for a broad range of sewage and special waste handling situations including high head and low flows and where large solids are present. The recessed impeller creates a liquid vortex in the volute, which directs all spherical solids, slurry, sludge, grit, stringy or fibrous material through the pump without clogging. The recessed impeller or vortex pump is used in applications where the liquid being pumped contains large amounts of solids or debris that could clog or damage the pump's impeller.