Perforated rotary cutter

An apparatus for comminuting solid waste material is provided an includes a casing defining a comminution chamber and being open on opposite sides thereof for permitting the flow of liquid therethrough and a comminutor assembly including cooperating substantially parallel first and second shredding stacks. The comminutor assembly includes first and second parallel shafts rotabably mounted, 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, the 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 at least one cutting tooth has a plurality of serrations, a tapered profile or a bi-level profile.