The changes in Colorado’s composting rules are kicking in this weekend after the state’s largest compost manufacturer has struggled to handle the large volume of contaminants that end up in its supply chain.

Starting Saturday, people who participate in composting programs, including Denver’s, should only put food and yard waste in their bins. All packaging, paper, utensils and other products that claim to be compostable or biodegradable — with one exception — must go in the regular garbage.

“When in doubt, throw it out,” said Clinton Sander, marketing manager for A1 Organics. “Don’t put it in the bin.”

A1 Organics is the largest compost manufacturer in Colorado, and earlier this year the company announced it was altering the products it will accept for composting. The company takes material from Denver, Boulder and other large cities along the Front Range as well as from schools such as the University of Colorado Boulder and other large venues and events that compost.

The company found too many contaminants such as glass bottles, greasy pizza boxes and plastics such as trash bags and dinnerware in the material being delivered to its property in Keenesburg, Sander said. Now, it has mounds of compost that it cannot bag and sell to the public because those materials are mixed in with actual organic product.

“That’s the challenge we face when you have a fantastic quality compost with small pieces that look like trash,” Sander said. “No one wants that. We don’t want that.”

A1 is looking for ways to use the compost that it cannot sell because company leaders don’t want to send it to a landfill, he said. The company believes the product could be used in agriculture or as a soil filler in grassland areas because the non-organic pieces are small.

At first, A1 said it would not allow anything in its compost supply except food and yard waste. However, the company recently decided to allow certain compostable-certified garbage bags. They must be 3 gallons or less, approved by the Compost Manufacturers Alliance and can only contain food scraps. A list of approved bags is available on the company’s website at a1organics.com/acceptables.

“We have to reset this stream and we have to bring awareness to what the challenges are when you put the wrong thing in the wrong bin,” he said.

Composting reduces the amount of waste poured into the state’s landfills and reduces greenhouse gas emissions. As it grows in popularity, it’s been challenging to keep the supply chain clean.

Some products such as paper towels, plates, cups and utensils are packaged to look like they are compostable although they are not. Some are labeled “biodegradable,” but that is not the same as compostable, Sander said.

He used brown paper towels as an example. Some are made of plant fiber and break down easily, but others are not. And people start confusing which paper towels are acceptable and toss them all into their compost bins.

“The problem is when you say ‘paper towel,’ people assume every paper towel can go in the bin.”

The company also has found that loads of material coming from Denver’s composting program often have garbage in them. That’s likely because the city’s green bins are not locked or monitored as they sit in alleys, and anyone can toss something inside, Sander said.

“When COVID kicked in, we saw a huge uptick in face masks and sanitation wipes that do not belong in the bin,” he said.

So it’s time to step back and get everyone on the same page of what is acceptable.

“We’re trying to focus on what’s important and make it really simple,” Sander said.

The Dos and Don’ts of Colorado’s new composting rules

What can you put in the bin?

As a general rule, if you can eat it or feed it to an animal, you can put it in your bin.

That includes:

Eggshells
Coffee grounds
Cereal
Pretzels and chips
Meat, raw or cooked
Fruit peels and cores
Chicken skins and bones
Old leftovers from the fridge
Small branches (Check with hauler for maximum size.)
Grass trimmings and clippings
Leaves
Weeds
Dead house plants

What to leave out?

Old dirt/soil
Limbs and branches longer than two feet
Pizza boxes
Paper towels
No packaging even if it says compostable
Diapers
Glass
Trash bags, except for certain compostable-certified garbage bags
All plastics
Fruit and vegetable stickers

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