Sink waste disposal units are usually fitted directly under the kitchen sink and are used to grind soft waste (such as vegetable peelings, tea bags, fruit skins, fruit stones, nutshells, corncobs, crust etc.) to a pulp before it gets into the drain. The pulp is then washed down the drain without causing a blockage.
Disposal units are also available as free standing models if an under sink model is not suitable. Selection of a garbage disposal unit should be based on quality and performance. Motors are relatively trouble-free, and unlikely to fail during a reasonable life-span.
Metal parts in contact with waste and water (turntable, lugs, chamber, and shredding ring) are very prone to corrosion, and last much longer if made of stainless steel or similar corrosion- resistant material rather than non-stainless steel. The size of the chamber and power of the motor determines the amount of waste processed per unit time.
Some manufacturers use standard mountings for all their models, making it very easy to replace a unit by any model of the same brand. Many standard disposal units allow a dishwasher to be connected, and some more expensive dishwashers are equipped with a small built-in waste disposal unit, making it unnecessary to scrape plates before washing them.
Cold water should always be kept running when the disposal is switched on to prevent damage to the blades and wash away the chopped waste without allowing it to build up and clog the drains. Hot water tends to melt easily-flushed solid shredded pieces of fat, which can then solidify and block the drain.
Under no circumstances should oil or grease be disposed in a sink drain – with or without a disposer in use.