How to make all your food waste disappear
Composting is not for everyone.I realize this when I go home to visit my parents in Florida, or almost anywhere outside states, such as Vermont, that mandate it. Curbside pickup is rare. Many view it as a chore. Even for people like me who enjoy transforming leftovers into rocket fuel for their garden, composting can turn into a foul, stinking, sulfurous mess.But what if you could make food waste disappear by throwing it into a hole in the ground and walking away. No more fouled trash. Less climate pollution. While researching ways to compost, I discovered an easy method to turn virtually any organic waste from veggie scraps to chicken bones to pet waste back into nature: solar digesters.They don’t produce compost, the rich, fluffy organic matter that turns back into soil. Instead, these biodigesters — typically little more than half-buried plastic cones within a small patch of dirt — harness microbial workhorses and the sun’s heat to transform organic matter into its elemental components, mostly carbon, water, CO2 and micronutrients, says Yichao Rui, a soil scientist in the Department of Agronomy at Purdue University. “Nematodes, bacteria and fungi all work together to decompose all these organic materials,” he says. “Soil organisms large and small primarily digest and eat them,” transforming plant and animal matter back into the building blocks for soil and air.It’s a simple, easy, no-mess solution to keep organic waste out of trash and landfills: 58 percent of all methane emissions from municipal landfills are emitted by rotting food.So this January, I ordered my own “Green Cone,” buried it in the ground, and began filling it with lots of food waste every week to put it to the test. Here’s what happened.The mounting food waste problemEach year, the average household in the United States dumps 300 to 400 pounds of food waste into the trash, according to the Environmental Protection Agency. When this is buried in the airless depths of landfills, it turns into methane, a potent greenhouse gas fueling still more warming.States and federal agencies are hoping to choke off this source of global warming fuel. First, they hope to prevent food waste: encouraging less wasteful food shopping and storage, as well as donations and upcycling (such as reusing for animal feed). But waste will always exist, and a rising share of states now treat food waste similar to recyclables: a valuable material that should never go into the trash.On July 1, 2020, Vermont became the first U.S. state to ban the disposal of most food scraps in the trash or landfills. Most trash haulers must offer food scrap collection or residents can use home composting (residents who compost at home are not required to compost meat and bones — although you can). State officials estimate more than half of food scraps are now being diverted from landfills. Eighty-five percent of Vermonters compost, mostly in their backyards, according to the University of Vermont. Only about a fifth characterize it as “hard or very hard.”States are following Vermont’s lead by adopting food waste restrictions, says Dana Gunders, executive director of ReFED, a food waste reduction group. While most policies initially focus on large businesses, residential mandates become more feasible once compost and distribution facilities are in place. Ten states including Massachusetts and New York, as well as Washington, D.C., now restrict organic waste disposal. “I do think the emerging science demonstrating food in landfills is responsible for around 10 percent of U.S. methane is driving more attention to organic waste bans and diversion goals,” says Gunders.What are solar digesters?Solar digesters remain little known. For now, “soil savers” ($52), an insulated compost bin for cold climates, and “barrel composters” ($38), a compost bin or drum you can rotate to mix the contents inside, are the most popular, says Josh Kelly, a solid waste program manager at the Vermont Agency of Natural Resources.But solar digesters are poised to play a much larger role as organic waste bans spread.The most popular design is probably the Green Cone. The digester ($200 retail, or subsidized by many waste agencies) is a two-foot high cone above a plastic mesh basket buried a few inches underground that holds food scraps. The cone concentrates the sun’s heat. A bacterial culture, or “accelerator powder,” is sprinkled on the food scraps occasionally to speed decomposition.The plastic mesh basket allows soil microbes and invertebrates to join the party, while the large air chamber ensures aerobic conditions suppress smells. Since it’s buried underground, most animals are excluded, although wire mesh is recommended if burrowing animals become a problem.How much food waste can it handle? Two pounds per day, or the equivalent of food scraps from one to two families, says Karl Warkomski of Tar River Trading Post, the distributor of Green Cones in the United States. He says a combination of warm internal temperatures as high as 130 degrees and tailored microorganisms make quick work of almost any organic matter, even bones and pet waste (with a special bacterial culture). Every few years, anything remaining in the basket can be dumped. Only woody biomass like branches and yard waste, and industrially compostable plastic are not recommended.How well did my solar digester work?On a warm spring morning, I positioned my Green Cone in my backyard and began filling it with food waste. Over the subsequent months, it consumed everything I threw at it. The level of waste never rose more than a few inches. At one point, I did have a little unwanted help: a burrowing animal broke into the underground basket. I fixed it with cheap wire mesh. It’s still going to this day.Is a solar digester for everyone? You will need to dig a hole in well-drained ground and get enough sunlight. If you have waterlogged or clay soils, you’ll need to elevate the cone so the digestion chamber stays moist, but not soaked. Decomposition slows, but does not stop, in the winter so long as there’s sun exposure. If it’s too pricey (Warkomski says high manufacturing costs in Canada, the United States and Britain, as well as the use of high-grade recycled plastic contribute to higher costs), share with another family or, if you have the time, you can DIY you own.Composting doesn’t have to be hard. With a solar digester, it’s almost too easy. Weeks might go by without emptying the trash. Recycling takes care of the bulkiest things. My Green Cone handles the rest.
Composting is not for everyone. But you haven’t tried solar digesters.
Composting is not for everyone.
I realize this when I go home to visit my parents in Florida, or almost anywhere outside states, such as Vermont, that mandate it. Curbside pickup is rare. Many view it as a chore. Even for people like me who enjoy transforming leftovers into rocket fuel for their garden, composting can turn into a foul, stinking, sulfurous mess.
But what if you could make food waste disappear by throwing it into a hole in the ground and walking away. No more fouled trash. Less climate pollution. While researching ways to compost, I discovered an easy method to turn virtually any organic waste from veggie scraps to chicken bones to pet waste back into nature: solar digesters.
They don’t produce compost, the rich, fluffy organic matter that turns back into soil. Instead, these biodigesters — typically little more than half-buried plastic cones within a small patch of dirt — harness microbial workhorses and the sun’s heat to transform organic matter into its elemental components, mostly carbon, water, CO2 and micronutrients, says Yichao Rui, a soil scientist in the Department of Agronomy at Purdue University. “Nematodes, bacteria and fungi all work together to decompose all these organic materials,” he says. “Soil organisms large and small primarily digest and eat them,” transforming plant and animal matter back into the building blocks for soil and air.
It’s a simple, easy, no-mess solution to keep organic waste out of trash and landfills: 58 percent of all methane emissions from municipal landfills are emitted by rotting food.
So this January, I ordered my own “Green Cone,” buried it in the ground, and began filling it with lots of food waste every week to put it to the test. Here’s what happened.
The mounting food waste problem
Each year, the average household in the United States dumps 300 to 400 pounds of food waste into the trash, according to the Environmental Protection Agency. When this is buried in the airless depths of landfills, it turns into methane, a potent greenhouse gas fueling still more warming.
States and federal agencies are hoping to choke off this source of global warming fuel. First, they hope to prevent food waste: encouraging less wasteful food shopping and storage, as well as donations and upcycling (such as reusing for animal feed). But waste will always exist, and a rising share of states now treat food waste similar to recyclables: a valuable material that should never go into the trash.
On July 1, 2020, Vermont became the first U.S. state to ban the disposal of most food scraps in the trash or landfills. Most trash haulers must offer food scrap collection or residents can use home composting (residents who compost at home are not required to compost meat and bones — although you can). State officials estimate more than half of food scraps are now being diverted from landfills. Eighty-five percent of Vermonters compost, mostly in their backyards, according to the University of Vermont. Only about a fifth characterize it as “hard or very hard.”
States are following Vermont’s lead by adopting food waste restrictions, says Dana Gunders, executive director of ReFED, a food waste reduction group. While most policies initially focus on large businesses, residential mandates become more feasible once compost and distribution facilities are in place. Ten states including Massachusetts and New York, as well as Washington, D.C., now restrict organic waste disposal. “I do think the emerging science demonstrating food in landfills is responsible for around 10 percent of U.S. methane is driving more attention to organic waste bans and diversion goals,” says Gunders.
What are solar digesters?
Solar digesters remain little known. For now, “soil savers” ($52), an insulated compost bin for cold climates, and “barrel composters” ($38), a compost bin or drum you can rotate to mix the contents inside, are the most popular, says Josh Kelly, a solid waste program manager at the Vermont Agency of Natural Resources.
But solar digesters are poised to play a much larger role as organic waste bans spread.
The most popular design is probably the Green Cone. The digester ($200 retail, or subsidized by many waste agencies) is a two-foot high cone above a plastic mesh basket buried a few inches underground that holds food scraps. The cone concentrates the sun’s heat. A bacterial culture, or “accelerator powder,” is sprinkled on the food scraps occasionally to speed decomposition.
The plastic mesh basket allows soil microbes and invertebrates to join the party, while the large air chamber ensures aerobic conditions suppress smells. Since it’s buried underground, most animals are excluded, although wire mesh is recommended if burrowing animals become a problem.
How much food waste can it handle? Two pounds per day, or the equivalent of food scraps from one to two families, says Karl Warkomski of Tar River Trading Post, the distributor of Green Cones in the United States. He says a combination of warm internal temperatures as high as 130 degrees and tailored microorganisms make quick work of almost any organic matter, even bones and pet waste (with a special bacterial culture). Every few years, anything remaining in the basket can be dumped. Only woody biomass like branches and yard waste, and industrially compostable plastic are not recommended.
How well did my solar digester work?
On a warm spring morning, I positioned my Green Cone in my backyard and began filling it with food waste. Over the subsequent months, it consumed everything I threw at it. The level of waste never rose more than a few inches. At one point, I did have a little unwanted help: a burrowing animal broke into the underground basket. I fixed it with cheap wire mesh. It’s still going to this day.
Is a solar digester for everyone? You will need to dig a hole in well-drained ground and get enough sunlight. If you have waterlogged or clay soils, you’ll need to elevate the cone so the digestion chamber stays moist, but not soaked. Decomposition slows, but does not stop, in the winter so long as there’s sun exposure. If it’s too pricey (Warkomski says high manufacturing costs in Canada, the United States and Britain, as well as the use of high-grade recycled plastic contribute to higher costs), share with another family or, if you have the time, you can DIY you own.
Composting doesn’t have to be hard. With a solar digester, it’s almost too easy. Weeks might go by without emptying the trash. Recycling takes care of the bulkiest things. My Green Cone handles the rest.