Calling Anaerobic Digestion “Composting” Is Greenwashing
This year when my partner and I moved back to New York City, I was determined to compost.
I grew up composting, and it’s something that I see as an under-discussed and needed tool to fight climate change.
I found the story of NYC’s expanding compost programs. It turns out, it’s a lot of greenwashing.
For example, they have placed hundreds of these orange “compost” bins throughout the city. But these food scraps aren’t turning into fresh soil. They’re getting brought to massive industrial facilities, where they’re treated to become a mix of biogas and biosolids.
This isn’t composting. It’s a different process called anaerobic digestion.
While it has some advantages (which I’ll give it credit for), it’s not a true circular process that’s key for fighting climate change.
Over the years, I have learned about crises like the myth of plastic recycling and other instances of “greenwashing,” and I’ve learned to be skeptical.
We can just take companies and governments at their word. We have to investigate for ourselves.
Calling “Anaerobic Digestion” Composting Is Misleading. It’s a Classic Case of Greenwashing.
If you’re unfamiliar with the term “greenwashing,” it refers to the practice of companies or governments presenting themselves as environmentally friendly to improve their image, even when their actions fall short of real sustainability.
Jenny Price gives a great definition of it in her book Stop Saving The Planet. She writes, “We’re seeing an intensifying whirlwind of greenwashing, as the world’s largest, highest-polluting, and most powerful companies rapidly ramp up their efforts to convince you they’re ‘saving the planet!'” The same goes for governments, who also want to convince the people electing them that they’re taking action on climate.
In this case, labeling anaerobic digestion as “composting” gives the public the impression that their food scraps are being returned to the earth in the form of nutrient-rich soil. But in reality, the process produces no soil and still burns the food scraps into the atmosphere.
While anaerobic digestion does keep food waste out of landfills and produces biogas as a renewable energy source, it’s not the same as composting and pretending it does mask the actual environmental impact. It’s a subtle form of deception that makes people feel like they’re contributing to a sustainable, circular process when, in truth, they’re supporting a system that doesn’t address soil health and climate resilience.
This is greenwashing at its core: giving the appearance of environmental responsibility without delivering on the true benefits.
I know that this can sound abstract, so let’s go through the differences between these two processes in more depth.
Composting vs Anaerobic Digestion: The Quick Summary
At first glance, composting and anaerobic digestion might seem like two sides of the same coin, both working to reduce food waste. However, the processes and outcomes are quite different.
Composting is a natural process where organic materials, like food scraps, break down with the help of oxygen (aerobically). The result is rich, nutrient-dense soil known as compost, which can be used to enrich gardens and farms. It’s a closed-loop system that focuses on returning organic matter back to the earth, improving soil health, and reducing the need for chemical fertilizers.
Anaerobic digestion, on the other hand, occurs without oxygen and is primarily designed to produce biogas, a renewable energy source, while keeping food waste out of landfills.
Those may seem equally good. (That’s what governments and corporations who profit off of it want you to think.)
Let’s Talk about The Environmental and Social Impacts of Composting vs Anaerobic Digestion
Soil Regeneration and Soil Quality: Composting vs Anaerobic Digestion
The main, indisputable difference is that composting makes soil and anaerobic digestion does not.
This in turn has numerous benefits.
- High-quality soil sequester’s carbon. This means it sucks more carbon out of the air. In contrast, low-quality soil releases carbon into the air. At scale, this can massively combat increasing greenhouse gas emissions.
- Increased soil quality helps all other plants grow. Helping other plants grow indirectly leads to more carbon sequestration.
- Because the soil is healthier, it also disincentivizes the use of synthetic fertilizers, which are a major contributor to water pollution. Synthetic fertilizers often lead to runoff, where excess nitrogen and phosphorus seep into nearby waterways, causing harmful algal blooms and “dead zones.”
- Better soil resiliency to floods and drought alike.
- Prevents soil runoff and erosion.
This is why composting is often called “black gold.” It actively rebuilds the earth, ensuring that food scraps complete their natural cycle by returning to the soil
Since anaerobic digestion does not create more soil, it provides none of these crucial benefits.
In fact, because anaerobic digestion doesn’t produce compost, I don’t like that the process is called “composting.” This is deceptive language and flat-out greenwashing.
Greenhouse Gas Emissions
To anaerobic digestion’s credit, it still helps prevent greenhouse gas emissions in a few ways.
Keeping Food Waste Out of The Landfill
When food waste goes into the landfill, it stews in a pile of garbage that causes it to emit methane, a greenhouse gas that’s 25x more potent than carbon dioxide.
By keeping food waste out of the landfill, both composting and anaerobic digestion limit the creation of methane.
In some ways anaerobic digestion does this better, in other ways it does this worse. The good news is that animal scraps can go into an anaerobic digestor. In traditional compost, you leave out animal waste so that it doesn’t smell and attract critters from rats to raccoons to bears.
However, it also does it worse in other ways. According to a report in the New York Times, only 75% of food waste is converted into biogas. 20% becomes biosolids, which can be used as fertilizer but if they run into nearby water sources, it can contaminate the water. The last 5% still goes to the landfill.
Anaerobic Digestion Still Produces Lots of Greenhouse Gases
While anaerobic digestion does prevent methane emissions that would otherwise come from food scraps rotting in landfills, the process itself still generates methane and carbon dioxide.
Even as biogas, even if it’s getting used to heat homes, it’s still ultimately turning into earth-heating greenhouse gases.
And that’s the best-case scenario.
Composting, on the other hand, can actually have a negative carbon footprint, as composting sequesters carbon by returning organic matter to the soil.
There are also serious questions about what’s happening to the biogas, and whether it’s even getting used as a fuel source.
Is Biogas Actually Replacing Fossil Fuels? Or Is It Just Getting Burned?
In theory, biogas from anaerobic digestion can replace natural gas, a fossil fuel, and reduce the need for environmentally destructive practices like fracking. However, while it’s promoted as a “clean” energy solution, the actual environmental benefits are questionable. Biogas still relies on combustion, releasing carbon dioxide and other pollutants into the atmosphere. So, while burning food scraps may be better than burning fossil fuels, we’re still trading one form of pollution for another.
In New York, the city has struggled to add the biogas produced from food waste to the national energy grid. In some cases, instead of being utilized as fuel, much of this biogas has simply been burned off into the atmosphere, a process called flaring.
Flaring biogas not only wastes the energy potential but also emits pollutants like carbon dioxide and methane directly into the air—negating any environmental benefits the program might have promised.
The lack of transparency, as reported nicely by Gothamist, around how much biogas is actually making it to the grid and how much is being wasted leaves us all in the dark. Without clear accountability, it’s hard to know if biogas is truly reducing the city’s carbon footprint, or if it’s just yet another form of greenwashing.
Composting offers a simpler, more direct solution. It doesn’t require the complex infrastructure or energy conversion that biogas relies on, and it avoids the problem of combustion entirely.
Ultimately, while biogas might seem like a convenient stopgap for diverting food waste from landfills, it doesn’t address the root issues of climate change or waste management.
Finally, there are also serious concerns about which communities are going to bear the brunt of processing all this food waste.
Environmental Justice: Concentrating Pollution in Vulnerable Communities
One of the most troubling aspects of anaerobic digestion programs is their potential impact on vulnerable communities. For example, in New York City, the main anaerobic digestion facility is located in Greenpoint, Brooklyn—a historically industrial area that has long been burdened by pollution from nearby oil refineries, waste treatment plants, and power stations.
As these anaerobic digestion programs expand, more treatment facilities like the one in Greenpoint will be needed to handle the increasing volume of food waste. Unfortunately, these facilities are likely to be built in similar low-income, industrialized areas where environmental regulations are often more relaxed, and communities have less political power to resist.
This pattern is part of a broader trend known as environmental racism, where the burden of pollution and industrial activity disproportionately falls on marginalized communities.
Anaerobic digestion plants generate noise, odors, and air pollution, contributing to the cumulative environmental stress already present in these neighborhoods.
And while proponents of these facilities highlight the production of “green” energy, the reality is that the communities living near these plants often bear the brunt of the environmental harm, while the benefits are exported elsewhere. Again, more greenwashing.
The bottom line is if cities like New York expand anaerobic digestion to encompass all food waste, they’re going to need to build more community-harming plants.
By contrast, community-based composting is a decentralized approach that empowers local residents to manage their food waste while enriching their neighborhoods. These small-scale, local initiatives reduce waste at the source without the need for large, polluting industrial facilities.
Big Waste Management Companies vs. Community Groups
Finally, there’s an economic justice discussion.
Anaerobic digestion often supports large waste management corporations, which make money by the pound, and are worried about losing profits as we make less trash. This can undermine smaller, community-based composting initiatives. These community efforts not only help the environment but also foster local jobs, education, and stronger community bonds. Supporting local composting keeps the power in the hands of communities rather than large industries.
I’m generally a believer in not letting the pursuit of perfection get in the way of progress. For example, I’m a big advocate for not high-speed rail. But often, the shift to anaerobic digestion is actively undermining community composting.
New York City Cut Its Budget For Community Composting, While Expanding Anaerobic Digestion
In late 2023, New York City cut funding for the NYC Compost Project. This project supports many community-based organizations around the city to do actual composting.
Meanwhile, they continue to ramp up anaerobic digestion. I believe community groups compost most effectively and have shown they can handle a remarkable amount of food waste and use it to help the environment and the people who live here.
Cutting that funding is an absolute disaster, and the organizations that work under the NYC Compost Project have all been forced to scale back.
The Advantages of Anaerobic Digestion: It’s Greenwashing, But It’s Not All Bad
While anaerobic digestion has its flaws and is often used as a vehicle for greenwashing, I acknowledge its legitimate advantages.
It’s not inherently bad—it just shouldn’t be conflated with composting or used to overshadow more community-driven, transparent, and ecologically beneficial approaches.
Here are some of its advantages, and how it can be used in tandem with composting, not compete against it.
Capacity to Process Large Amounts of Waste in a Smaller Space
The first question is “scale.” Well, can you scale community composting? I believe you can. There are enough community gardens, backyards, and other spaces to handle way more than we currently do. If it’s true in densely-packed New York, it’s true in any city.
(Composting is just another of the numerous benefits of community gardens.)
However, it is true that anaerobic digesters can handle large volumes of food waste in relatively small spaces.
With our current decentralized compost infrastructure, the orange bins and curbside composting in New York City, make it easy for many to keep their food scraps out of the landfill.
Even seeing the option to separate food waste, I believe, brings it into people’s awareness. This can then be the next step for education on composting. However, I wish city governments were more transparent about where these food scraps go, opening the door for even more education.
Ability to Process Meat and Dairy Waste
Meat and dairy are excluded from traditional compost piles because they attract pests, produce odors, and take much longer to break down.
Anaerobic digestion, however, is designed to handle these types of waste, making it uniquely suited to manage the wide range of organic materials produced by urban areas.
Ideal for Restaurant and Commercial Waste
Here’s a great example of a good use case for anaerobic digestion: restaurants.
For example, according to the National Resource Defense Council, 20% of food waste in New York City comes from restaurants. Even if that’s not exact, and even if it varies by place, that’s a big chunk of the pie.
As someone who worked as a dishwasher in high school, I know it’s unrealistic to ask kitchens to sort the chicken bones from the banana peels.
Anaerobic digesters are particularly well-suited for processing large-scale, uniform food waste, such as the kind produced by restaurants, grocery stores, and food manufacturers.
This is Not a Call Against Anaerobic Digestion: It’s a Call for Transparency, Accountability, and Support for Community Composting
Anaerobic digestion has its place in urban waste management, especially for large-scale food waste that is difficult to handle through traditional composting.
However, it’s crucial that these programs are transparent about their environmental impacts and not falsely marketed as “composting.” The public deserves to know that while anaerobic digestion has some benefits, it is not the same as the circular, soil-regenerating process of composting.
Moreover, anaerobic digestion should not overshadow or replace community composting initiatives, which offer both environmental and social benefits. Community composting keeps the process local, transparent, and grounded in soil regeneration rather than energy production. It fosters stronger, more resilient neighborhoods, creates local jobs, and contributes directly to healthier ecosystems.
Support Community Composting
While large-scale solutions like anaerobic digestion get a lot of attention, community composting is a proven, effective, and sustainable method that deserves much more support. For decades, local community gardens, environmental groups, and grassroots organizations have been quietly doing the work of transforming food waste into healthy soil and building stronger neighborhoods and healthier ecosystems. It’s time we recognize and invest in these efforts, rather than allowing industrial-scale solutions to monopolize the conversation around waste management.
They’ve Been Doing It for Decades
Community composting is not new. Local groups and volunteers have been managing small-scale composting operations for decades, turning food scraps into nutrient-rich soil and using that soil to grow gardens, trees, and green spaces in urban areas. These initiatives have long demonstrated that composting works, both in terms of waste reduction and the broader environmental benefits. The community composting movement has been a quiet force for environmental good.
They Actually Can Scale With Local Government Support
One of the biggest misconceptions about community composting is that it can’t scale. However, with proper local government support, these programs can grow to meet the demands of urban food waste. Municipalities can provide funding and logistical support to help community composting programs expand their reach.
They Do It Better
At its core, community composting does what industrial-scale solutions can’t: it creates healthy, nutrient-dense soil and reinvests it back into the local community.
This Is What We’re Doing at Maria Sola Community Garden
In about five months, we’ve kept 200 lbs of food scraps out of the landfill.
I also convinced (coerced?) my girlriend’s extended family in Connecticut to compost.
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