What is a garbage disposal?
This page is part of the Garbage Disposal Guide.
A garbage disposal is an electronic device, also known as a food or under-sink compactor, that grinds up biodegradable food waste and scraps under your sink. Then the food particles are flushed away with water down to drain. The disposer is installed inside one of your kitchen cabinets and sits between the sink drain and the drain pipe.
In the disposal unit, you will find a rotating grinding plate with swiveling metal impellers that grind and shred the food waste into small particles. These food remains are then flushed into your sewage system through your plumbing. It is also an option to connect your dishwasher hose to the discharge of the garbage disposal unit.
How does it work?
An in-sink garbage disposal doesn’t work the same way as a paper shredder, blender or food processor. This means that it doesn’t shred or chop the food scraps with sharp cutting blades. Rather, an under-sink garbage disposal grinds food scraps with a plate or grinder wheel.
The wheel is equipped with pointy impellers or lugs which spins around extremely fast, creating a centrifugal force. When biodegradable green waste is fed into the unit, the wheel grinds up the food forced against a stationary grinder ring. The remaining food particles are then washed down the drain with, preferably, cold water.
The use of cold water is recommended to prevent possible clogging due to solid fats.
Video: How does a InSinkErator garbage disposal works?
Video: What happens inside a food waste disposer?
Will ground food waste clog the drain pipes?
A garbage disposal should not clog your drain pipes if it is used properly. But a jammed up disposal unit or clogged drain pipe can happen. Here are a few reasons why your drain pipes can clog. It can clog because:
- Fat, grease or oil was disposed of with warm or hot water, which congeals inside the drain pipes.
- Hard, stringy, or fibrous food waste was fed into the disposer which couldn’t be processed properly and jams up the disposer or drain pipes.
- Too little water was used to wash the food waste particles away which caused a jammed up drainpipe.
The pros and cons of a food waste incinerator
- Reduce the volume of food waste.
- Convenient and hygienic way of disposing of food scraps.
- Relatively easy to install under most kitchen sinks.
- It keeps food scraps away from landfills.
- Your trash can doesn’t smell bad anymore.
- Requires minimal energy (3-4 KWh a year / 50¢ a year).
- Composting food scraps is more eco-friendly.
- Some garbage disposers can make quite some noise.
- Not every disposer unit might fit your kitchen cabinet.
- After a while a garbage disposal can have a bad odor because of bacteria.
- Some disposers can’t grind and process stringy or fibrous food scraps.
- A food scrap disposal can jam, overheat or leak water.
- It is possible that drain pipes get clogged.
- Some disposers require extra parts for installation which are not included.
- A continuous feed garbage disposal requires approximately one gallon of water a day.
- Not recommended when you make use of a septic tank.
- Wastewater treatment is more difficult because of food waste particles.
- Not every garbage disposal might fit your sink, such as a farmhouse sink or Kraus sink.
A garbage disposal is also known as a food waste incinerator. And in Canada this device is called a garburator.
Features to look for
What are the most important features of garbage disposals and which ones should be taken into consideration when looking for a disposal to buy? Below you can find a list of important features that will help you choose the best garbage disposal for your needs.
- Induction or Permanent magnet motor – While factually speaking permanent magnet motors are the better option, consumer reviews and experiences clearly show the induction motors, especially ones from InSinkErator, can also get the job done well with their multiple grinding stages which make up for the motor’s disadvantages.
- Batch feed or Continuous feed – Do you want a disposal unit that can run continuously? Or do you want a safer food waste disposer which only runs in batches? In short, a continuous feed disposer keeps running until you turn it off and you can add waste to the unit while it runs. Meanwhile, a batch feed disposal only grinds up food waste in small batches and the device is closed while on so you can’t add more food waste.
- Plastic or Metal mount – If noise is a concern or you want a durable garbage disposal mount then you should opt for a sturdy metal mount, which minimized vibrations and with that noise and everyday wear and tear. However, if you don’t mind a little noise or have a limited budget then a plastic mount will definitely serve you well too. If you find noise level an important characteristic of disposal and would like to read more about quiet disposals you can check out our blog post on in.
- Power of the motor – How much power do you need? It all depends on the number of food scraps you want to grind during the day or the number of users. We recommend choosing at least a 1/2 horsepower disposal. When you have lots of food waste or a large household you need more horsepower to process and dispose of all the food waste.
- Light use (1-2 users) – 1/3 HP
- Medium use (2-4 users) – 1/2 & 3/4 HP
- Heavy use (4-6 users) – 1 HP (can handle almost all types of food scraps, check our recommended 1 HP garbage disposals)
- Grind stages – Waste disposers can have one, two or even three grinding stages. More stages mean smaller food particles, and thus a lesser chance of clogging. In general, more powerful garbage disposals have two or three grind stages, also known as multi-grind stages. The less powerful models only come with one or a single grind stage. When you want to grind up all kind of food scraps, including (small) bones, then it is recommended to look for a waste disposal which comes with a two or three-stage grind system.
- Size of the unit – Make sure the garbage disposal can fit under the sink base and in the kitchen cabinet. It is also important to check if there is enough room to install the unit, as well as the drain pipes and optional hose for your dishwasher.
- Built quality – A waste disposal with good built quality will last longer, is quieter and vibrates less during use. When you are choosing your unit make sure it is made of stainless steel metal and that the mount, which connects the disposer to your sink, is durable.
- Ease of installation – The installation of a food waste disposal is supposed to be quite easy, but the installation process may vary per brand. Most popular brands, like Waste King and InSinkErator, try to make it as convenient as possible to install the unit in your kitchen cabinet by offering a product with a user-friendly mount system. If you are not sure how to install the unit properly, you can also hire an expert to install the unit for you.
- Power cord – Not all garbage disposals come with an attached power cord. With some units, you will need to buy and attach a power cord yourself.
- Air switch – With an air switch you can activate the disposal by pressing a button that is installed in a convenient spot in your kitchen, for instance, it can be mounted in your countertop near your sink. The button sends an air pulse to the control box that switches on the garbage disposal. You don’t need electricity, the switch works with just air that is pushed through PVC tubing to the control box.
- Connecting to dishwasher – If you have a dishwasher that you want to connect to the disposal it is recommended to look for one with an inlet for the dishwasher. Most garbage disposals have an inlet for connecting the dishwasher hose. This inlet is closed with a plug that needs to be removed before connecting the dishwasher to the unit. You may need to purchase a dishwasher kit that connects these two machines to each other.
- Warranty – Check the warranty for each brand and model before purchasing a food waste disposer. Some manufacturers offer a lifetime limited warranty, while other brands only offer a warranty of a few years.
- Can your plumbing handle it – Before installing a food waste disposal make sure your plumbing and the shared sewage system can digest food particles. Please investigate with your local municipality whether it is permitted to use a garbage disposal.
Alternatives for kitchen waste disposals
What else can you do to dispose of your food scraps in the kitchen? Besides using a kitchen waste disposal there also some other alternatives you can consider. Such as:
Garbage Disposal Guide
Garbage Disposal Guide
Tips for buying a garbage disposal
By Recycling.com/ 21 February 2020