Garbage disposal unit

[citation needed] Hammes' claim is disputed, as General Electric introduced a garbage disposal unit in 1935,[3][4] known as the Disposall.

Burned in waste-to-energy facilities, the high water-content of food scraps means that their heating and burning consumes more energy than it generates; buried in landfills, food scraps decompose and generate methane gas, a greenhouse gas that contributes to climate change.

[21] The premise behind the proper use of a disposer is to effectively regard food scraps as liquid (averaging 70% water, like human waste), and use existing infrastructure (underground sewers and wastewater treatment plants) for its management.

[22][23] A high-torque, insulated electric motor, usually rated at 250–750 W (1⁄3–1 hp)[24] for a domestic unit, spins a circular turntable mounted horizontally above it.

The added weight and size of induction motors may be of concern, depending on the available installation space and construction of the sink bowl.

Two swiveling and two fixed metal impellers mounted on top of the plate near the edge then fling the food waste against the grind ring repeatedly.

Usually, there is a partial rubber closure, known as a splashguard, on the top of the disposal unit to prevent food waste from flying back up out of the grinding chamber.

Batch feed models are considered safer, since the top of the disposal is covered during operation, preventing foreign objects from falling in.

Instead of the turntable and grind ring described above, this alternative design has a water-powered unit with an oscillating piston with blades attached to chop the waste into fine pieces.

Water-powered units take longer than electric ones for a given amount of waste and need fairly high water pressure to function properly.

[30] Metcalf and Eddy quantified this impact as 0.04 pounds (18 g) of biochemical oxygen demand per person per day where disposers are used.

[35] In a study at the Hyperion sewage treatment plant in Los Angeles, disposer use showed minimal to no impact on the total biosolids byproduct from sewage treatment and similarly minimal impact on handling processes as the high volatile solids destruction (VSD) from food waste yield a minimum amount of solids in residue.