Food waste is a major problem. Most food waste end up in landfills, where it releases methane when it decomposes. Methane is a greenhouse gas which contributes to global warming. Given the huge amounts of food waste this is a big problem. Food waste is the second largest type of waste that ends up in landfills. Garbage disposals is one way of limiting the amount of food waste that ends up in landfills. But does that also mean that garbage disposers are good for the environment? Well, that is difficult question to answer.
The garbage disposal shreds food waste into small particles which are transported via the sewer system to a waste water treatment plant rather than to landfills. A modern waste water treatment plant can convert the food waste into biogas. In some places in Europe garbage disposers have been installed in order to take advantage of this. Biogas is environmentally friendly and can be used for electricity production, heating and, in compressed form, as fuel.
So far so good but garbage disposals also have some drawbacks. For example, not all waste water treatment plants can turn the food waste into biogas. Older plants need expensive upgrades before they can start producing biogas. Plants that can not convert food waste into biogas often get rid of the waste in environmentally unfriendly ways. The use of garbage disposers may also create problems in the sewer systems. Some cities have banned garbage disposals, fearing that they will damage the sewer system.
Another thing to take into consideration is that garbage disposals use both water and electricity in order to grind food waste. According to some researchers, this increased usage of water and electricity more or less nullifies the advantages of garbage disposers. But not everyone agrees, you can find studies which conclude that garbage disposers are environmentally friendly. It worth noting that various pressure groups have sponsored studies about the environmental impact of garbage disposers. Unsurprisingly, these studies often come to the same conclusions as their sponsor is trying to promote. Manufacturers of garbage disposers regularly release studies that show that garbage disposers have many advantages. Owners of old water treatment plants which can not convert the food waste into biogas on the other hand like to point out that the use of garbage disposals have disadvantages.
One things the experts agree on is that the best solution on the food waste problem is to try to reduce the amount of food waste in the first place. For consumers this means, buy only food that is needed and make sure that everything gets eaten. Composting is a better solution than garbage disposals but obviously composting is not a feasible solution for everyone.
Note that there is a fundamental difference if food waste ends up in a compost or in a landfill. At first, it may look like it does not matter but composting is a much better solution than landfills. Food waste in landfills undergo anaerobic decomposition, that is without oxygen, which produces methane. Food waste in a compost on the other hand undergoes aerobic decomposition, which produces carbon dioxide instead of methane.