The garbage disposal was invented in 1927 by John W. Hammes. He was an architect working in Racine, Wisconsin. After eleven years of development, his InSinkErator company put his disposer on the market in 1938.
In many cities in the United States the municipal sewage system had regulations prohibiting running food waste (garbage) into the system. InSinkErator spent considerable effort, and was highly successful in convincing many localities to rescind these prohibitions. Many localities mandated the use of disposers.
Garbage disposal units became popular in American kitchens of the better-off in the 1970s and 1980s. The EU prohibited the use generally with the option for member countries to make exceptions, but there are only few countries allowing its use, and local authorities generally emphasize the prohibition: the reason is supposedly the additional load on sewage treatment plants which would make sewage treatment more expensive than the composting of kitchen waste.
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, shredding ring) are very prone to corrosion, and should be made of stainless steel or similar corrosion-resistant material rather than non-stainless steel, even if galvanized. The length of manufacturers' warranties gives some indication of quality, but most units should last much longer than their warranty period.
The size of the chamber and power of the motor (in horsepower or watts) determine the amount of waste processed per unit time. Soundproofing to reduce the noise of operation adds cost.
Some manufacturers use standard mountings for all their models, making it very easy to replace a unit by any model of the same brand.
Source - wikipedia.com