Garbage disposals are mounted to the underside of a sink and is designed to collect solid food waste in a grinding chamber. When you turn on the disposal, a spinning disc, or impeller plate, turns rapidly, forcing the food waste against the outer wall of the grinding chamber. This pulverizes the food into tiny bits, which then get washed by water through holes in the chamber wall. While disposals do have two blunt metal "teeth," called impellers, on the impeller plate, they do not have sharp blades, as is commonly believed. Garbage disposals need to be maintained and can tend to clog or seize, causing unpleasant odors or harmful bacteria growth. repairing or replacing a faulty garbage disposal will help keep you and your kitchen healthy.