How Does Industrial Or Commercial Composting Work?

While I have talked many times about how to compost at home and what items to avoid when composting… would you believe me if I told you that all composting is not created equal? 

It’s true! Even an item labeled “compostable” may not break down in your backyard or indoor compost bin, as some items require very specific pressures and temperatures to turn into usable compost. This process, also known as industrial or commercial composting, is covered today! 

What is it, and how do we know the difference between an item that can be composted “normally” vs. an item that can only be composted in an industrial setting? What role do we, consumers who want to practice sustainable living, have in this story? 

Let’s find out!

Understanding the Concept of Industrial Composting: What Are the Methods?

Private commercial composting first came on the scene in the 1970s when smaller companies that served farms, livestock growers, and the timber industry needed a way to dispose of large amounts of organic waste and realized there was profit to be made by sending it to be composted. 

To better understand industrial composting, we first must discuss the main factors contributing to a “compostable” item’s ability to break down. According to the Environmental Protection Agency (EPA), there are five key areas they consider here: 

Feedstock and nutrient balance: Proper composting requires the right balance of “green” and “brown” materials. Green materials might include grass clippings, frozen veggies, or other food scraps… the nitrogen-rich stuff! While brown materials include carbon-rich items like paper towels, paper, wood chippings, or branches. 

Pro tip: The best environment for composting has the perfect balance (usually a 2:1 ratio of the green and brown stuff). 

Particle size: Shredding materials before being composted increases the surface area where microorganisms can feed, creating a more homogenous mixture in a compost pile. 

Moisture content: Having enough water in a compost pile is VERY important since moisture helps transport nutrients throughout the pile. 

Oxygen flow: There is a reason I always recommend turning your compost pile over every so often! Turning your compost pile helps to aerate the compost and speeds up the overall decomposition process. 

Temperature: The right temperature in your compost pile can help speed up decomposition and destroy pathogens and weed seeds. In fact, by properly controlling the last four factors and promoting microbial activity, the core of a compost pile can sometimes reach temperatures up to at least 140° F! Compost piles can get so warm they can even be used to heat hot tubs.

Industrial compost handling. Pin

Industrial vs. Home Composting: What's the Difference?

Now that we know what factors are at play during the composting process, how is commercial composting different from at-home composting? 

The heat, moisture, and general conditions in an industrial composting facility are much more intense than in the compost piles and bins at home. Industrial composting differs from at-home composting by scale, processes, and required equipment. 

Let's first look at the scale of both types of composting…

At-Home Composting

At-home composting can be a small, non-smelly operation (yes, you can even compost in your apartment). Composting can also be done outdoors in larger piles.

Industrial Composting

Industrial composting tends to be much larger and can handle high volumes of organic waste. For example, with windrow composting, the piles can be up to 16 feet wide and 8 feet tall!

What about the composting process itself?

At-Home Composting

There are so many different types of composting!

For example, at-home composting can happen with the help of microbes or by vermicomposting (when you use worms to speed up the decomposition process). 

To begin the composting process at home, it helps to shred or tear up your organic matter, and you should monitor your bin or pile often to ensure you have the right mix of green and brown items. 

The process is also much slower at home (depending on if you are composting in the winter) and can take up to six months for the organic matter to break down.

Industrial Composting

Unlike composting at home, industrial composting removes you from the composting process once a private or municipal hauler comes to pick up your bin. 

Instead of hauling this waste to the landfill, the organic waste will be sent to a special commercial composting facility.

While items are breaking down in an industrial setting, they will be exposed to a much more controlled environment where the main composting factors I discussed earlier are much more managed. 

Industrial composting also happens much faster, and in a commercial setting, items can break down into nutritious soil in just a few weeks.

Lastly, what kind of equipment do you need?

At-Home Composting

To compost at home, you only need an indoor or outdoor bin! If you are vermicomposting, you will also need your worm friends.

Industrial Composting

If you are participating in a municipal, commercial composting program, you may need the collection bin provided by your municipality and compostable bags.

Overview of Different Methods in Industrial Composting

Windrow Composting: Waste is piled in long, tall rows, watered, and turned periodically. 

In-vessel Composting: Waste is stored in a drum, concrete-lined tench, or silo where the surrounding environment can be more controlled.

Aerated Static Pile Composting: Waste is mixed with wood chippings or shredded paper. Aeration is further supported by a series of pipes that blow air throughout the mixture. 

Commercial composting truly is sustainable technology at its best!

Introduction to Compostable Products: Their Role in Industrial Composting

The definitions of “at-home compostable” and “commercially compostable” are not that different! Compostable items are organic items that will break down aerobically (with oxygen) with the help of some microorganisms in the soil.

Pro tip: biodegradable and compostable are not the same thing! Biodegradable essentially means that a product can break down with or without oxygen, and it won’t necessarily turn into nutrient-rich compost (also known as hummus or black gold) at the end.

Eco-friendly disposable bamboo cutlery, paper and sugarcane containers for food and drinks over green background. Side view on composition. Plant branch in bottle behind.Pin

What Does Commercially Compostable Mean?

Commercial composting follows a similar definition as at-home composting… but commercially compostable items might not be considered at-home compostable. In contrast, at-home compostable items will usually also be considered commercially compostable. 

It’s a mind-bender… I know!

Industrial composting facilities can break down more complex items since they have special equipment to help the decomposition process. With this in mind, a commercially compostable item is an item that will break down into nutrient-rich organic matter in an industrial composting facility. 

Breaking Down Commercial Composting Systems: A Look at Guidelines and Standards

Sustainability, certifications, and standards are important to this story. The Federal Trade Commission has guidelines on what can be labeled “compostable.” 

According to their guidelines, marketers should “qualify compostable claims if the product can’t be composted at home safely or in a timely way. Marketers also should qualify a claim that a product can be composted in a municipal or institutional facility if the facilities aren’t available to most consumers.”

ASTM International also sets standards for labeling items “compostable.” At the same time, the Biodegradable Products Institute (BPI) provides a credible, third-party certification to ensure these standards are being upheld. 

For context, the FTC and ASTM International agree that a “commercially compostable” product must break down in 180 days in an appropriate facility. 

What Can and Can't Be Industrially Composted: Understanding the Materials

I think we are ready to now talk about which items can be composted in a commercial setting but not at home… here are some examples:

These items are usually not compostable at home! Although I want to mention that not all commercial composting facilities will accept these items for the last three. Hence, double-checking in advance is a good idea (especially with biodegradable vs. compostable trash bags).

You can also compost items you would normally compost at home in a commercial setting. The breakdown process will likely happen faster! Some examples include:

  • Grains,
  • Frozen veggies
  • Fruit
  • Coffee grounds,
  • Yard waste,
  • Wood chippings

Pro tip: If you are growing a sustainable garden or trying out sustainable landscaping this spring, be sure to compost your yard waste this summer, either at home or commercially!

Why is Industrial Scale Composting Important?

Composting, at home or commercially, is GREAT for the environment! Composting helps remove food waste from landfills and reduces the potential for soil erosion and our need for synthetic fertilizers and pesticides. If you are into low-waste living like me, I highly recommend you start composting!

Industrial composting takes these benefits one step further. When organic materials decompose anaerobically (without oxygen), it releases methane gas, a potent greenhouse gas responsible for more than 25 percent of the warming we are experiencing today. 

I understand that not everyone will want to compost their organic waste at home, so by offering composting programs through commercial facilities, municipalities can help slow climate change and contribute to a brighter future. 

The Roadblocks in Industrial Composting: Addressing Challenges in the Industry

One of the biggest challenges in industrial composting is contamination. Similar to contamination and recycling, when an item is placed in the incorrect disposal bin, this can contaminate an entire bin or waste stream. 

Toxins like herbicides in grass clippings, yard waste, and stickers on fruits like bananas or apples are two common sources of composting contamination. 

While man-man additives like stickers might not necessarily harm the composting process, this can make everything a big mess and be tricky (and expensive) to sort through.

A person composting. Pin

Municipal Composting Programs: How to Locate and Participate

So, what role do we as consumers have here? 

Organic waste is more than 56% of municipal solid waste (MSW), and only about 8.5% of America’s organic waste is composted! 

By using municipal composting programs and ensuring organic waste is disposed of properly (or by advocating for ones in our community), we are helping divert organic waste from landfills and contribute to more sustainable communities. 

Decoding the Term: What is a Municipal Composting Program?

Municipal composting programs will look different depending on where you are located. 

For example, San Francisco became the first U.S. city to establish a citywide food composting program and composts and recycles about 80 percent of its waste. Portland is another great example of a municipal composting program, composting about 70 percent of its landfill waste!

Steps to Find and Engage with Local Composting Programs

There are a few ways to get involved in your municipal composting programs. The first step is to identify what programs are available to you. You can use tools like BioCycle’s Find a Composter to find an industrial composting facility near you. Depending on where you live, paying for a private collection pickup might also be an option. 

A final word on commercial composting

As we stand on the precipice of an ecological crisis, the Food and Agriculture Organization paints a sobering picture — by 2050, a staggering 90% of our topsoil could be degraded. One of our most effective shields against this alarming prognosis? Good old compost. A silent warrior in preserving our fertile grounds and securing our future food supplies.

Now, let's add another layer to this. According to the EPA's Municipal Solid Waste report, over half — yes, you read that right, half — of landfill waste could have been composted. In 2018 alone, we saw an astounding 292.4 million tons of waste, but a mere 25 million tons underwent composting. This puts our municipal waste composting rate at an underwhelming 0.1%.

The case for industrial composting could not be clearer. It's not just a route to more sustainable food waste solutions. It's a crucial component of our collective response to environmental challenges. So as we journey towards sustainability, remember that every compostable item is a small victory for our planet. Looking for more ways to live sustainably? Stay tuned.


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