Food

Dec 02, 2023

Between fruit peels, vegetable trimmings, coffee grounds and spoiled foods, a certain amount of ... [+] "organic waste" is inevitable at the household level

Many consumers want to be as responsible as possible when it comes to the food-related waste they generate at home. They can be careful about not getting too far ahead on purchases of perishable food items. They can learn that it isn't always necessary to automatically discard items that have passed their "best by" date. Even so waste does happen when life gets busy, when some recipe disappoints, or when fresh items succumb to a post-harvest disease. Also, if one consumes healthy quantities of fruits and vegetables, that generates a significant volume of peels, rinds, trimmings etc. So consumers are inevitably going to generate some "organic waste" and need to find climate-responsible way to deal with it. The worst case scenario is to put it in the trash so that it goes to a landfill because there it will lead to emissions of the potent greenhouse gas, methane. In several states including California consumers are being encouraged or required to put "organic waste" in with the yard waste for composting. While that is better than the landfill route, there are still problems. Unless one keeps the waste in the freezer until trash day it generates unpleasant odors and attracts flies and rats. Once it gets to a large-scale composting facility it can still generate some methane. So, what are some other alternatives?

It is certainly possible to have one's own compost pile, but in most cases it just ends up being a place to bury the waste and let it decompose as opposed to a true "hot compost" that does some degree of sterilization. The pile can also attract flies and rats.

A home worm bin

There are "worm bins" and if successfully managed those do a great job of turning the waste into a good fertilizer for the garden. There are certainly householders who make these systems work, but they are not a viable solution for many others.

A process called "anaerobic digestion" is widely used on an industrial scale to convert organic waste into energy. There is a company called HOMEBIOGAS® that has developed a household scale digester which can be placed in a typical back yard. The householder puts their food-related waste, compostable bags and even pet waste into the unit which then generates a safe, low pressure supply of biogas.

One of the Homebiogas digesters in a backyard garden

Each kilogram of waste can provide enough energy for about one hour of cooking. It has a filter to remove sulfur compounds, so it is clean burning. Alternatively, the gas can be used to heat water or run a small electric generator. There is also an output of liquid fertilizer for the garden. Though these systems cost $900 or $800 on sale, they can pay for themselves within 2-3 years through energy savings. Thirty thousand of these systems are in use around the world including more than two thousand in the US. The units have also been deployed through the UN, CSR projects and government tenders in places like Africa, India, and El Salvador".

A digester unit supplied as part of a United Nations CSR project

Food waste in the home generally has a very high moisture content and so drying it is a logical first step. There are several brands of home, counter-top dehydrators available that can take most food-related waste, grind it, heat it and dry it to generate a much lower volume of mulch-like material that is quite usable in the garden.

Clockwise: a Lomi countertop dehydrator. Some oranges to be juiced. The rinds and pulp from the ... [+] oranges. The end product mulch ready to spread in the garden

Even if the mulch is put into the yard-waste bin it is far more compatible with existing large-scale composting systems. A popular example is the Lomi Processor produced by the Canadian company, Pela Earth. These systems cost between $3-500, but particularly for consumers who generate a lot of produce trimmings (e.g. this author), they offer a practical way to fulfill climate-related aspirations. The dehydrator can handle most kitchen waste, but not something like an avocado seed or bones.

In conclusion, consumers can enjoy the many benefits of a healthy, produce-rich, home-prepared diet, and still have a variety of climate-responsible options for dealing with the inevitable organic waste it generates.