There are two main types of in-sink garbage disposals: continuous feed and batch feed. Depending on your personal preference, frequency of use, and types of waste most often disposed of, either one might be right for you.
Continuous Feed Disposals
The most common garbage disposal found in a home uses a continuous feed. This means that food waste can be added to the disposal as it is running. You turn the disposal on by flipping a switch, completing an electrical circuit and bringing power to the disposal. Most people recommend running some water while the disposal is in use.
When the switch is activated and the disposal is running, you can send food waste down the disposal, where it is ground up and sent through your septic system. With this type of system you can continue to chop food simultaneously while the disposal is running, although this uses a lot of electricity. Instead, you could choose to run the disposal only when you are finished.
Batch Feed Disposals
A batch feed disposal works the same way as a continuous feed disposal, except it is started with a special cork-like cover that goes over the disposal entrance. This means that no food can be ground up while the disposal is working. Most people do not find this any less convenient than needing to flip a switch. If you are disposing of a lot of food at once, this system would take more time.
Sometimes a batch feed disposal is confused with a food compactor, because both must be closed in order to be activated, and they both compact food waste into a more manageable size. A batch feed disposal, though, is still an in-sink system that grinds food before sending it through the septic system and onto a water treatment facility. On the way, solid waste is separated and sent to landfills—where the waste from compactors is sent anyway. Many items that can be put in a compactor (cardboard, for example) cannot be put in a disposal, and items that can be put in a disposal (like food waste) should not be put in the compactor if it will be left in there for a few days. There it will potentially leave bacteria and germs, as well as attract insects.
A Word on Safety
The main drawback of continuous feed disposals is that they are more dangerous than batch feed disposals. There is no cover on the disposal, as food is being sent down manually, posing a threat to fingers and hands. Never put your hand near the mouth of the disposal while it is running. Always turn it off before fishing an item out or moving the food around. You can use the water faucet to propel food near the disposal instead of using your hand.
You can find both batch feed and continuous feed garbage disposals for around $160, and sometimes under $100. In general it is easier to find a continuous feed system for under $100 than a batch feed disposal, although both are available.
Either a continuous feed or batch feed system should grind your food equally as well, but each person will need to decide which system fits better with their lifestyle.