What is composting and why does it matter?

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What is composting — and why does it matter? The answer lies in food waste and reducing greenhouse gas emissions.

Every year, people around the world send approximately 931 million tonnes of food to landfills—waste that includes things like rotten household food; unfinished scraps from “super-sized” restaurant meals; and grocery store items that fail to sell before their “best before” dates.

This is problematic on many levels.

For one, people are throwing out perfectly good food at a time when 9.6% of Canadians and 10.2% of Americans suffer from food insecurity. Second, growing, processing, packaging, shipping, and disposing of this unused food takes a terrible toll on our environment.

Creating a more circular economy that reduces and repurposes food waste would be the most effective step in resolving both these challenges. However, that system doesn’t yet exist on a public scale, but we can mitigate some of the environmental damage of food waste by composting it rather than sending it to a landfill. In fact, research indicates this step alone can reduce greenhouse gas emissions by more than 50%.

How? Well, that’s what we’ll dive into in this article.

Topics we’ll explore in this article:

  • How food waste contributes to climate change
  • What is composting and what is compost used for
  • How composting helps reduce environmental impacts
  • The beneficial applications of compost
  • Why it’s important to consider participating in a composting program now

The environmental impacts of food waste

While it’s true that all organic waste eventually decomposes over time, the way it decomposes in a landfill—where it’s likely sitting in plastic garbage bags, surrounded by a host of non-organic matter—is quite different from how it decomposes in a compost pile.

During the first phase of landfill decomposition, the organic matter uses oxygen to break down—a process called aerobic decomposition (meaning “with oxygen”). Within about a year, however, the supply of oxygen runs out—which is when the anaerobic decomposition (“without oxygen”) phase begins. With anaerobic decomposition, bacteria break down the organic matter further—releasing methane gas as a by-product.

Why is methane gas so bad for the environment?

Methane is a greenhouse gas which is considered to be significantly more powerful at accelerating global warming than carbon dioxide. To understand why, it’s helpful to refer to the US Environmental Protection Agency’s (EPA) three metrics for assessing a greenhouse gas’s power—concentration, longevity and strength.

Carbon dioxide beats methane on the first two metrics—it’s the most concentrated greenhouse gas in the atmosphere (making up 80% of emissions, compared to methane’s 10%). Carbon dioxide also stays in our atmosphere much longer—between 300 and 1000 years, compared to 12 years for methane. Where methane overshadows carbon dioxide is strength (otherwise known as warming potential). It’s 28 times more effective at trapping heat in the atmosphere over a 100-year timescale, compared to carbon dioxide.

Landfills are key emitters of methane gas, thanks to—you guessed it!—food waste. According to Canada’s Greenhouse Gas Inventory, 23% of the country’s methane emissions come from landfills—or approximately 1,401 kilotonnes.

What is composting?

Composting is an excellent option to help reduce the amount of methane entering the atmosphere. By diverting food waste to either a backyard compost, community compost facility, or commercial/industrial compost program, we can, in many cases, eliminate the anaerobic phase of decomposition (and the production of methane) altogether.

This is because composting doesn’t just provide food to bacteria. It also attracts insects, worms, and fungi by providing an ideal balance of nitrogen and carbon, as well as a free flow of oxygen. While these creatures emit carbon dioxide as a by-product, the impact on the environment is significantly lower than methane production.

So, what does composting mean? It means diverting waste, encouraging a natural biodynamic ecosystem, and reducing methane. These benefits are, in part, why composting is important.

Backyard vs commercial composting

While backyard composting is a great option for single-family dwellings—or homes with some sort of outdoor space—this isn’t typically an option for restaurants, multi-residential buildings, offices, schools, grocery stores, cafeterias, packing plants, and other producers of food waste. Home composting also doesn’t create the right environment to break down things like meat, bones, dairy, grease, or oil.

In these instances, you need large-scale composting programs—run by municipalities or private corporations. These composting programs accept all forms of food waste and, depending on the program, may also accept things like:

  • Paper napkins, paper towels, tissues
  • Yard waste
  • Coffee grounds, filters, tea bags
  • Food-soiled paper plates and takeout containers (provided they’re not waxed or plastic-coated)
  • Soiled paper bags
  • Food-soiled pizza boxes
  • Paper muffin cups (not waxed or parchment)
  • House plants, including soil
  • Pet waste
  • Diapers
  • Feminine hygiene products

4 types of composting programs

The items a program accepts depends, in part, on its composting system. Typically, a program will fall into one of four categories:

Aerated (Turned) Windrow Composting

With this large-scale composting option, organic waste is laid out in long piles called “windrows”—typically four to eight feet high, and 14 to 16 feet wide. The goal is to make the piles big enough so they can generate sufficient heat to facilitate the decomposition process, while making sure they’re small enough to turn (or mix the compost around, which ensures sufficient oxygen flow and decomposition throughout).

Aerated Static Pile Composting

This type of composting also uses oxygen to break down organic matter. Unlike windrow composting, however, these composting piles don’t have to be turned. Rather, they’re comprised of a homogeneous mix of organic waste interspersed with layers of loosely piled “bulking agents”—like wood chips, egg carton containers, and shredded newspaper—which create air pockets that allow air to flow through. In some forms of aerated static pile composting, piles may be placed over a series of air-blowing pipes to enhance airflow.

In-Vessel Composting

This option is great for composting large amounts of waste with a minimal footprint. Unlike windrow composting, which requires a lot of space, in-vessel composting simply requires a drum, silo, concrete-lined trench, or something similar. Once the vessel is closed and set to the required temperature, moisture, and airflow, the compost is ready in a few weeks or months.

Anaerobic Digestion Composting

This type of composting is primarily designed to create biofuel—a renewable form of energy comparable to natural gas. Essentially, this type of facility uses micro-organisms to break down organic waste in the absence of oxygen—producing methane which, unlike in landfills, is ultimately captured and used for fuel. The remaining organic matter is then shipped to another facility to decompose into compost.

While burning biomethane does emit carbon dioxide, it doesn’t increase the carbon dioxide levels in the atmosphere—largely because the organic matter that’s being used would have emitted the same amount of carbon dioxide if it was left to decompose naturally.

What is compost used for?

After the organic matter completes the composting process, it transforms into nutrient-rich soil (or compost). This material is used by municipalities for landscaping or infrastructure purposes, distributed to local farms, or sold to individuals and businesses—and it offers a host of benefits.

Erosion control

Erosion is most often caused when moving water—from rain, crashing waves, or something else—carries or washes away sediment over time. Understanding this, compost can be a great tool to prevent erosion due to its ability to bind soil together and slow water flow.

Stormwater Management

While compost is great at helping sandy soil bind together, it’s also great at helping heavy—or saturated soils—absorb more water. This comes in handy when controlling stormwater flows because when excess stormwater is strategically absorbed by compost-rich soil, it can alleviate pressure on municipal storm sewers and mitigate flooding.

Healthier Plant Growth

Compost-rich soil is full of nutrients and microorganisms that not only help plants grow—but makes them more resistant to rising temperatures. Additionally, because of compost’s aforementioned ability to efficiently absorb and transfer water, it helps plants withstand droughts.

Carbon sequestration

Healthy soil, rich in organic matter, allows microbes to flourish and ultimately absorb vast amounts of carbon from the atmosphere through photosynthesis. In fact, studies indicate that while traditional soil doesn’t store or emit much carbon, soils rich in compost store carbon for up to 20 years—making them an excellent “carbon sink” to mitigate climate change.

Why is compost important?

Because food waste is such a huge contributor to climate change, the United Nations has identified it as an urgent problem that needs to be fixed. To encourage action, it has set a global goal to cut per capita global food waste in half by 2030. This includes reducing food waste at the retail and consumer levels, as well as throughout post-harvest processes.

Whether it’s in response to this initiative, a desire to reduce landfill waste, or something else, a growing number of municipalities are introducing regulations around the disposal of organic waste.

In the United States, cities like Austin, Boulder, Portland, and Seattle—and states like California, Connecticut, Maryland, Vermont, and Washington—have introduced a range of bills and laws that outline voluntary recommendations and mandatory regulations around the disposal of organic waste.

In Canada, provinces like Ontario, Nova Scotia, and PEI outline either voluntary program recommendations or mandatory organic waste targets and policies for residents and businesses—while countless municipalities across the country have also introduced curbside composting programs.

To date, California likely has the most stringent regulations to combat organic waste:

  • SB I383 makes it mandatory for cities, counties, and other jurisdictions to decrease their methane gas emissions by reducing the amount of organic waste they deposit in landfills by 75%. The first phase of the bill, which took effect in January 2023, requires jurisdictions to recover 30% of organic waste—a number that will increase to 65% on January 1, 2024, and 100% on January 1, 2025.
  • SB 54, still in progress, will make it mandatory for all packaging sold in the state to be either recyclable or certified compostable by 2032. The Bill will also establish an extended producer responsibility program that would fund all reuse, recycling, and composting programs throughout the state.
  • SB 1046, which takes effect in January 2025, will make it mandatory for all businesses to offer recyclable paper shopping bags or compostable bags instead of single-use plastic shopping bags.

Frequently Asked Questions about Composting and Why it Matters

Here are some common questions and answers to them on composting and why it matters.

1. What is composting?

Composting is the process of decomposing organic materials, such as food scraps and yard waste, in a controlled environment.

2. What are the benefits of composting?

Composting has numerous benefits for the environment. First and foremost, composting reduces waste in landfills. Composting reduces greenhouse gas emissions by diverting organic waste from landfills, where it releases methane, a potent greenhouse gas. Composting also improves soil health by providing a natural source of nutrients, and it saves money on fertilizers and soil amendments.

3. What types of materials can be composted?

Most organic materials can be composted at home, including fruit and vegetable scraps, yard waste (grass clippings, leaves), coffee grounds, eggshells, and shredded paper. However, some materials need to be composted in a professional setting, such as meat, dairy, and fats.

4. How does composting reduce greenhouse gas emissions?

Composting diverts organic waste from landfills, where it releases methane, a potent greenhouse gas. Methane has a global warming potential 25 times greater than carbon dioxide, so reducing methane emissions is crucial to fighting climate change. Composting also helps sequester carbon in the soil, which can help mitigate climate change.

What are some common composting myths?

There are many misconceptions about composting, such as the belief that it smells bad or attracts pests. However, with proper management, composting should not produce any foul odors or attract rodents.

Another myth is that at-home composting requires special tools or expertise, but all you really need is a bin, some organic material, and a little patience.

A third myth is that you cannot compost certain materials, like meat and bones, but with the right facility, you absolutely can.

Get started with composting

Given the impact food waste has on the climate—and with more regulations being introduced to divert food waste from landfill—it’s clear that large-scale composting will become more widespread in the years to come. Understanding this, it’s never too early to explore composting options in your area—and identify opportunities to reduce and divert food waste in your business or facility.

If you’re ready to get started, EcoSafe offers everything you need—from certified composting bags to bins. Learn more here—or contact us for more information.

Food loss and waste occur at each stage of the supply chain. The biggest proportion (about 37%) happens in the home.

ReFED, 2021