By Kate Worley
Composting is a controlled biological decomposition process in the presence of oxygen (aerobic) that produces a rich, dark, earthy soil amendment.¹ Organic inputs to the composting process can include yard wastes, food wastes, crop residues, manure, and biosolids, and a successful composting process requires the correct carbon to nitrogen balance of materials.¹
Greenhouse gas emissions and composting
The release of CO₂ through the composting process is considered biogenic, happening through natural biological systems, and therefore is not generally included in the greenhouse gas calculations that contribute to climate change. Composting can generate other gases, including methane and nitrous oxide, depending on the materials being composted and methods used. However, the basic concept of composting, being aerobic, means that organisms should mostly be giving off CO₂ in the process of breaking down.
So why is this better than other management practices such as landfilling? For comparison, landfilling food waste is estimated to generate at least 50% methane (oftentimes more) and 50% CO₂. ³ Also, food waste is the heaviest component of municipal solid waste (MSW), and landfill space is limited, so diverting food waste can reduce the cost of managing MSW and prolongs the life of landfills.
Composting produces a valuable soil amendment that has a multitude of benefits for the environment including:
The addition of organic matter (compost) to soil creates healthy soil environments, including healthier plants and biodiversity of microbes. Healthy plants, if grown and maintained correctly in healthy soils, can sequester carbon.⁴
Compost provides an environment for biodiversity of plant and animal populations
Healthy plants and soil microbes help with overall ecosystem health which can help with biodiversity of animal populations.⁴
Compost retains water more efficiently, keeping it onsite for its intended use, preventing erosion and run-off into storm drains and waterways.⁴
Compost can be supplied back to grocery stores, hotels and other outlets for their own use at their site even bagged and sold on shelf.
Composting in the U.S.
There are an estimated 5,000 compost facilities in the U.S., with the majority accepting only yard waste. Less than 5%, or around 200 total, accept food waste today and many of these do not accept compostable food-contact packaging.⁵ Many of the barriers to growth are related to cost and requirements to establish infrastructure where recycling participation, and closing the loop, is needed to justify the business case.⁶ Compost facilities have strict requirements related to construction, permitting, and management, particularly when accepting materials such as food waste. Transportation is costly. And participation in food recycling programs is needed to capture enough material. Additionally, a key factor that many forget is the need to support end-markets that sell recycled products (in this case, compost).
Now, on the bright side, food waste recycling mandates – and landfill bans – are providing a push for the recycling infrastructure to grow, including compost facilities. In addition, there are other food recycling pathway options across the U.S., including feeding animals and producing energy. As I have discussed in a previous blog, “The Benefit to Having Diverse Outlet Options for Food Waste Recycling,” a diverse recycling infrastructure for food waste is beneficial not only to allow for options across the U.S., but to also maximize the various benefits that recycling organics can have for the environment.
So, the million-dollar question is why throw food waste in a landfill when you can capture the nutrient value, ideally through the natural carbon cycle with little to no climate impact, through composting?
How to take action:
- What type of recycling service do you need? Determine type of waste (i.e., food, packaged food, compostable eatware).
- Find a service provider that will partner with your business on customized collection needs. Compost may be an option in your area. If it isn’t a current option, your service provider will find the best recycling outlet type to fit your needs.
- Support the recycled product market by purchasing compost for your business needs or at home. This ensures the circular process is completed with demand for the recycled end product (in this case, compost).
If you are a business or manufacturer that would like to learn more about recycling your food byproducts or other organic waste streams, contact Denali for more information. We can help you set up a customized program to fit your service needs, organic waste streams, and provide the best value.
About Denali
Denali is a leading expert and recycler in the U.S. organics recycling industry. In food waste alone, Denali was responsible for managing over 1.7 billion pounds of food waste from retail, foodservice, and industrial food processors in 2023. In recognizing the impact that food waste has on the climate, Denali is committed to working with customers to find innovative, data-driven solutions to reduce waste on the front end. Denali views what others consider “waste” as a valuable resource, manages multiple recycling facilities in the U.S., and has a sizeable fleet to transport organic wastes to a diverse network of recyclers. As a contributor to the circular economy, Denali closes the loop by producing valuable products from recycled organics, including animal feed, biodiesel, compost, tire lubricants, and mulch.
K
ate Worley is Vice President of Sustainability at Denali. She has worked for more than a decade with some of the largest companies in the world to drive sustainability and reduce waste.