Guide for Garbage Disposals
Grind Biodegradable Food Scraps & Flush It Down The Drain
More about Food Waste Disposers
What to do with food scraps in your kitchen at home or in the office canteen? You can throw the food waste away in a trash can, such as a dual compartment trash can, or you can compost the scraps in a composting bin. But you can also grind up your biodegradable food waste with a garbage disposal unit underneath your sink, and wash the food particles away down the drain.
Especially in urban environments a garbage disposal is an efficient and space saving solution to dispose of food waste.
A kitchen waste disposal unit is an easy, convenient and eco-friendly solution to dispose food waste in your kitchen at home, in the office or in a commercial environment; such as a restaurant or cafeteria. As a matter of fact, in the U.S. 50 percent of all homes have a waste disposal installed in the kitchen.
- What is a garbage disposal?
- Pros and cons
- How much does it cost?
- How does it work?
- What can go in and what not?
- Garbage disposal types
- Features to look for
- Waste disposal for dishwashers
- Waste disposal for septic system
- How to install a food waste disposal?
- How to maintain and clean?
- Alternatives for kitchen waste disposals
- Food waste and the environment
Which garbage disposal do you need for your food waste and scraps? Let’s find out in this buying guide.
What is a garbage disposal?
A garbage disposal unit is an electronic device, also known as a food or under-sink compactor, which is installed inside a kitchen cabinet between the sink drain and the drain pipe. Biodegradable food scraps can be flushed into the disposal unit through the drain opening with cold water. 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.
If you are curious about how a garbage disposal work follow this link to find out more.
The pros and cons of a food waste incinerator
- Reduce the volume of food waste.
- Convenient and hygienic way of disposing 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.
- Waste water treatment is more difficult because of the food waste particles.
A garbage disposal is also known as a food waste incinerator. And in Canada this device is called a garburator.
How much does it cost?
The price of a food waste disposer depends on a few factors, such as:
- The power of the motor (HP & RPM).
- The capacity of the unit.
- The amount of grind stages.
- The built quality.
- The type of garbage disposal.
- The brand of the garbage disposal.
- The number of operators.
- Additional accessories, tools and parts needed for installation.
More power means a higher price
Generally you can divide garbage disposal units into four categories:
- Light use at home (1/3 HP): $75-100
- Medium use at home (1/2 – 3/4 HP): $100-150
- Heavy use at home or office (1 HP): $150-500
- Commercial use for professionals (5+ HP): $2,500+
As you can see above, professional garbage disposals are much more expensive than food disposers you use at home. This is because commercial or industrial machines need to be very powerful in order to be able to continuously process high volumes of food scraps and other biodegradable waste.
Comparison of home & office disposal prices
Price comparison between popular brands
Below you can see a price comparison between three of the most popular brands for garbage disposals: InSinkErator, Waste King and Moen. We have compared multiple disposers, calculated the average price and compared this to the power of the engine in HP. Also, see our more in depth comparison between Waste King and InSinkerator here.
How does a food waste incinerator 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 grinded 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 congeal 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 drain pipe.
As nearly all house appliance, garbage disposals have been known to have problems and small malfunctions ever so often. These problems are more likely to occur on a more frequent bases with low power devices, but this can also happen to high power garbage disposals, especially when they are used incorrectly. Some of the common problems include clogging, leaks, no power in the disposal, strange noises and jams. These following links my help you with fixing your disposal as that explain, in several steps, how to fix some of the common problems. Please proceed to fix your disposal with caution and do not ever put your hands in it.
What can go in and what not?
What can go in?
- Biodegradable food scraps only.
What not to put in?
- Grease, oil and fat because it can congeal inside the drain pipes and clog up the sewer system.
- Fibrous and stringy food waste, such as celery and corn husk. (this is applicable for less powered garbage disposals).
- Meat bones, most disposal units can’t grind it up properly.
- Everything that isn’t food waste, such as packaging material.
In Sweden some larger cities encourage kitchen waste disposals because they want to mine the food waste for biogas.
Sometimes it can be a challenge to figure out whether or not the food scraps from your dinner are allowed to go in the garbage disposal. This is mostly because it is difficult to define exactly what food scraps can and cannot go into your at-home disposer, as this varies based on the manufacturer and the power of your garbage disposer model. However, there are some types of food waste that all disposers should be able to handle and other types of waste that should generally not go into your food waste disposal.
If a baby can eat it, then your disposal can handle it too.
Soft fruits and vegetables are fine to dispose
To begin, let’s name some straight forward food waste that your garbage disposal should be able to process without a problem. All garbage disposals can handle water, obviously, but more precisely using cold water is stronger recommended. A general rule of thumb for food wastes that can go into any food disposal is: if a baby can eat it, then your disposal can handle it too. If you have food scraps or leftovers that should be okay to put in your disposer, but for whatever reason you are unsure about it, you can help your disposal by cutting the scraps it into smaller pieces. Generally, soft fruits and vegetables without pits or seeds are fine and so are cooked fruits and vegetables. Other foods that any garbage disposal should be able to process include cereal, smoothie drinks, citrus rinds, and soups.
Chance of clogging and damaging
Unfortunately, the list of foods that cannot go in your garbage disposal is longer and a bit more confusing than the list with food waste that can be discarded in a disposer. Starting again with the more obvious non-food items, such as: cigarette buds, paper, and glass. And continuing with oil, grease, and fats, which are especially damaging if combined with hot water, as this combination further increases the chances of clogging. Next up are the hard food scraps like bones, seeds and pits which can damage the interior motor of your disposal. For example, beef or chicken bones, apple cores and peach or avocado pits.
Furthermore, expandable foods like pasta, rice, bread, or oatmeal should also not be thrown in the garbage disposal, as they will expand from the water in the chamber and cause clogging. Lastly, coffee grounds, eggshells, and high fiber foods such as artichokes, celery, lettuce, asparagus, carrots, corn husks, and potato peels also have been known to decrease a disposal’s performance by wrapping themselves around the blades.
As a final note, these are general recommendations and we advise consumers to consult the manufacturer directly for specific questions. Garbage disposals with more power can likely process some of the items listed in the “chance of clogging and damaging” paragraph but this should be researched based on the specific model and make. The recommendations described in this section should assure safe usage of all food waste disposal models, even the models with low power.
Garbage disposal types
Before buying a garabage disposal there are three characterics you should make a choice on, which will define the type of disposal you will opt for. These characteristics include:
- Type of motor (induction motors/permanent magnet motor)
- Type of feed (continous feed/batched feed disposals)
- Type of mount (metal mount/plastic mounts)
1. Induction motor & Permanent magnet motor
An induction motor is a high-speed electrical motor which is commonly used in InSinkErator and Kitchen Aid food waste disposals. The induction motor creates a constant flux through a physical connection to the rotor. Reaching the motors maximum RPM takes a longer in comparison to permanent magnet (PM) motor and maximum speed tends to be slower than that of PM motors. Generally speaking, the induction motor tends to be heavier too, but unlike PM motors, induction motors can have multiple grinding stages to make up for it.
A permanent magnet motor is an electric motor that uses permanent magnets, hence the name. These motors are more efficient than induction motors. Because of the magnets the motor produces a consistent and instantaneous motor flux. This means the motor instantly runs at maximum speed, so all the power is directly available. For a garbage disposal this is very convenient, especially when the chamber contains fibrous or large quantities of food waste. For bathed feed garbage disposals, a permanent magnet motor is preferable, because this type of waste disposals grinds up food waste in batches and thus needs the immediate power of the motor. Another advantage of a permanent magnet motor is that the unit is smaller and thus lighter. Also, it tends to clog up less often than induction motors.
Currently, the two leading brands for garbage disposals are Waste King, who use PM motors in their disposals and InSinkErator who use induction motors in their garboators. If you would like to know more but the differences between the two brands, and which one is better, you may want to read our more extensive blog post on the topic.
2. Continuous feed & Batch feed
There are two types of garbage disposal systems, continuous feed and batch feed. So, what are the differences and the pros and cons between these two types? And which one suits your needs best?
- The food waste incinerator keeps running as long as you want. This is especially convenient when you are cleaning the kitchen and continuously want to dispose food scraps during the cleaning process.
- A continuous feed is less expensive to buy in comparison with a batch feed incinerator.
- You need to run water when processing and washing away the food scraps. On average you use around one gallon of water per day.
- You can feed food waste into the food disposer while it is running. Therefore, it is recommended to be careful and never put hands or fingers inside the machine.
How to use a continuous feed garbage disposer?
- Load up the unit and close the sink flange before you grind up the food waste. The motor can only be started when the cover is placed into the sink opening. (don’t overload the machine).
- It will only run if the drain opening is closed, this is called ‘covered operation’. This way you can’t feed more food waste while the disposal unit is grinding. But this makes operation safer, especially for children.
- Because of this the batch feed disposal unit requires a stronger engine in comparison with a continuous feed food waste disposer, and therefore also tend to be more expensive.
- Grinding your food waste takes more time, because it is meant for grinding smaller amounts of food waste.
How to use a batch feed garbage disposer?
3. Metal mount & Plastic mount
When you want to purchase a durable food disposal it is recommended to opt for a metal mounting system rather than a plastic mount. This mount is what connects your garbage disposal to the kitchen sink. Generally, the higher powered food waste disposers are quite heavy so a metal mount will offer more durability but also stability. Plastic mounts are known to be less stable. This instability allows for more intense vibrations which makes your disposal noisier but also more prone to wear and tear in a shorter period of time.
Features to look for
What are the most important features of garbage disposals and which ones should be taken in consideration when looking for a disposal to buy? Below you can find a list with important features which will help you choose the best garbage disposal for you 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 jod 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 which 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 platic mount will definately 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 amount of food scraps you want to grind during the day or the number of users. We recommend choosing at least a 1/2 horse power disposal. When you have lots of food waste or a large household you need more horse power to process and dispose 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 means 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 more quiet 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 counter top 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 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 which needs to be removed before connecting the dishwasher to the unit.
- 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.
What garbage disposal do you need?
Take the quiz below and find out exactly which garbage disposals suits you best:
Waste disposal for dishwashers
Yes, it is possible to connect a dishwasher to you garbage disposal if the disposal unit has a connection for the dishwasher hose. But first, why would you want to connect your dishwasher to your food waste processor?
A dishwasher cleans your dirty dishes, cutlery, pots and pans. And in this cleaning process a lot of food waste is flushed down the drain. To prevent clogging of your drain pipes it is a good idea to grind the food waste with a food waste disposal. By connecting the disposal to your dishwasher the discarded waste water goes through the garbage disposal and gets grinded up before it is flushed away. Moreover, it is more convenient and space efficient to connect your dishwasher hose to the garbage disposal instead of using all kind of drain connector parts to bypass the disposal unit.
Waste disposal for septic system or septic tank
Can you use a garbage disposal if you have a septic system instead of the regular sewer system? A septic tank is watertight tank that stores domestic sanitary wastewater underground and is most commonly used in areas where there are no connected sewerage systems. If your waste water is stored in a septic tank it isn’t recommended to use a garbage disposal unit. Why is that?
How to install a food waste disposal?
The installation process varies per brand and garbage disposal type, but generally it comes down to the following steps:
- Safety gear – Safety first.
- Plumbers putty – For sealing the sink flange to the sink drain.
- Flat head screwdriver – For locking the mounting ring, which keeps the disposal unit in place.
- Connectors and drain pipes – For connecting the garbage disposal neatly.
- Tooth saw – For shorting drain pipe outlet.
- Paint scraper – To remove old plumbers’ putty.
- Towels – For cleaning possible water leakage.
- Bucket – For catching water when a possible leakage occurs.
- Hammer (optional) – For removing the plug from the outlet for connecting the dishwasher.
- Wooden dowel or steel punch (optional) – For removing the plug from the outlet for connecting the dishwasher.
General installation process:
Please note that the steps below are only an indication of the installation process. The process assumes that you want to replace your old garbage disposal (which is connected to your dishwasher) with a new one. Follow the steps in the instruction manual of your garbage disposal for proper installation.
- Make sure your current garbage disposal is empty.
- Make sure there is no water in your sink.
- Turn off the power at the electrical panel.
- Disconnect and unplug your current garbage disposal as stated in the instruction manual.
- Insert a screwdriver into the mount and use it as a handle and turn it anticlockwise to release the unit from the mounting ring. Be careful, the disposal unit is heavy and can fall down. So place something below the unit to prevent damage in the unit and cabinet.
- Remove the whole mounting assembly.
- Remove the sink flange and old plumbers putty with a paint scraper.
- Disconnect the dishwasher hose.
- Install new mounting assembly as indicated in the instruction manual. Use plumbers putty to install the sink flange thoroughly to the sink.
- Remove the plug from the dishwasher outlet from the garbage disposal. Use a hammer and a dowel to remove the plug properly.
- Connect the garbage disposal to the new mounting assembly. Use a screwdriver as a hand to lock the unit into the mount tightly.
- Make sure all the connections are secure. Run water to check for possible leaks.
- Plug in the power cord and turn the power on and test the garbage disposal.
How to maintain and clean a sink disposal?
After using a garbage disposal for soon time it might become dirty and even a bit smelly. Bad odors are caused by bacteria from food waste residues which forms inside the sink opening and in the garbage disposal. How can you clean a kitchen garbage disposal and how often does this need to be done?
According to Waste King, a manufacturer of garbage disposals, it isn’t necessary to clean your disposer. The disposer is a self cleaning device which cleans the internal parts with each use.
But what if you really want to clean the disposal and the drain? What are some tips you can follow? Below are some official tips and recommendations from InSinkErator, also a manufacturer of disposers.
- Lemons – Neutralize bad odors by grinding citrus fruit. Put some slices inside the disposal, run some cold water and start grinding. The lemon helps to clean the inside of the disposer and releases a fresh smell.
- Clean the baffle – The baffle is the part that sits inside the sink opening, it is also called a splash guard. This rubber part can become really dirty and smelly as well. So it is recommended to clean this part regularly with some hot water and dish soap.
- Ice cubes – You can use ice cubes to clean the components inside the grinding chamber of the garbage disposal. It is a misconception that ice will sharpen the blades of the garbage disposal, because disposers don’t contain blades but a rotating grinding plate with impellers.
Manufacturers of food waste disposers
What are the best brands for garbage disposals? Below you can find a list with the official websites from well-known and popular brands, in alphabetic order:
Alternatives for kitchen waste disposals
What else can you do to dispose of your food scraps in the kitchen? Besides using of a kitchen waste disposal there also some other alternatives you can consider. Such as:
- Recycling bin dedicated for biodegradable food waste
- Composting bin for composting food waste
Food waste and the environment
Food waste you throw in your garbage usually ends up on landfill. Inside this mountain of trash there is almost no oxygen which causes your food waste to start releasing methane gas as it decomposes. This methane gas when it is eventually released into the open is harmful for the environment. Because of how harmful it is to the environment an effort is been made by landfills to capture this gas. This so called ‘landfill gas‘ (LFG) can, after it is captured be converted and used as a source for renewable energy.
However, it is extremely difficult to capture all of this gas that is released on our vast and rapidly growing trash mountain ranges. But when you use a garbage disposal to discard of your food scrapes, which will eventually start releasing methane gas, the food waste ends up in the sewer system. These biodegradable food waste particles will, along with the water used to flush them away, end up in a waste water treatment plants (WWTP). While the sewer system transports your food waste to WWTP much quicker than fuel guzzling garbage trucks can transport your trash bags to the land, these WWT plants also captured the methane gas, released by your food waste, more efficiently than a landfill is able to.
Did you know? A typical household throws away over 470 pounds of food waste every year.
Therefore, the methane gas can be converted to biogas more quickly, and can then be used as a green energy source for something like electricity and heating. But it gets better, not only can your flushed away food scrapes be used to make green energy, but the WWTP can also filter and use the concentrated food waste remains, also called biosolids, as fertilizer products.
In the end one thing is certain, throwing your leftovers in your garbage disposal is better than throwing them in the normal trash. There may be better possibilities such as composting, but this opportunity is not ideal either and is certainly not an option that everyone can implement, especially if you live in an urban area.
If you’d like to know more about garbage disposals and their impact on the environment this article may interest you.
See how food waste is recycled
Step Up: Recycle, Reuse & Reduce
The three arrows of the recycling symbol represent the three main stages of the recycling process: recycling, reusing and reducing. Together the arrows form a closed loop. Step up and implement eco-friendly replacements in your daily life.
By Recycling.com/ 12 November 2019