Two-dimensional cutting features

An apparatus for comminuting solid waste material including a casing defining a comminution chamber and being open on opposite sides thereof for permitting the flow of liquid therethrough. The apparatus including cooperating substantially parallel first and second shafts, each including a plurality of cutting elements mounted on said first shaft in interspaced relationship with a plurality of second cutting elements mounted on said second shaft, each of said cutting elements having at least one cutting tooth thereon, said cutting elements being positioned between and separated in an axial direction by spacers which are coplanar with the cutting elements of the adjacent stack such that a cutting element from one stack and a spacer from the other stack form a pair of interactive shredding members, wherein the spacers have a textured or scalloped outer cylindrical surface.