a cassette for a waste disposal device , the cassette including an outer wall , an inner wall , a flexible tubing positioned between the outer wall and the inner wall , and a rim having a top surface and a bottom surface . the rim is positioned between the outer wall and the inner wall and extends from a top surface of the outer wall toward the inner wall . the bottom surface of the rim faces the flexible tubing , and the rim includes a plurality of protrusions on the top surface of the rim to engage with a rotation mechanism of a waste disposal device .