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Composting in Ramsey and Washington counties is going high-tech.

Residents of four cities there can now throw compost in the trash — and let artificial intelligence sort it out. Sort of.

With the counties' new Food Scraps Pickup Program, special compost bags can be thrown into garbage carts, where they're picked up by haulers, taken to the counties' waste facility and sorted using artificial intelligence and robotic arms that can pick it out.

If all of this sounds different than other curbside compost programs, that's because it is.

"We're probably one of the first communities with this size of a program to do it this way," said Sam Holl, facility manager of the Ramsey/Washington Recycling & Energy Center.

A pilot program expanded in October to all residents of Maplewood, North St. Paul, Cottage Grove and Newport. It's expected to be available to all Ramsey and Washington county residents eventually.

Artificial intelligence and robots

Conveyor belts carry garbage up to a small room at the Recycling & Energy Centerin Newport, the facility where Ramsey and Washington county residents' trash goes. There, a machine that bridges the belt scans trash as it moves through at 73 feet per minute, using artificial intelligence to identify food scrap bags based on their color and size.

Piles of trash were collected and sorted on the main tipping floor at the Ramsey/Washington Recycling & Energy Center in Newport.
Piles of trash were collected and sorted on the main tipping floor at the Ramsey/Washington Recycling & Energy Center in Newport.

Alex Kormann, Star Tribune

These food scrap bags aren't your run-of-the-mill compost bags. They're specifically designed to stand up to the ride on the garbage truck and the conveyor belt.

When the AI machine finds one, it tells a robotic arm just down the line where the bag is. In a quick, precise motion, the arm swings and grabs it, separating the food scraps bag from kitchen trash bags, expired Halloween pumpkins and other garbage.

At least that's how it happens much of the time. Sometimes, the AI misfires, sending the robotic arm to grab a bag that looks like a Food Scraps Program bag but isn't.

The technology is already used to identify aluminum cans, but using it to pull out food scraps bags is new, said Joe Heinz, the facility's maintenance manager.

Workers at the facility are teaching the equipment: Everything identified as a food scrap bag — correctly or incorrectly — is fed through the machine again so it can be told whether it guessed correctly or not.

For now, the food scraps are sent to a commercial composter. Eventually, they will be sent to be anaerobically digested to generate energy, Holl said.

Co-collection model

In Minneapolis and many other communities, residents can order a compost-dedicated cart that is picked up separately from trash.

In Ramsey and Washington counties, residents have waited longer for curbside composting, but the benefits of what's called a "co-collection" model, where trash and food scrap bags are picked up together, are many, said Annalee Garletz, food scraps recycling program supervisor.

For one, it's easy for residents and waste haulers because it doesn't change the structure of hauling. Second, it's available to renters and homeowners at no additional cost beyond what they're already paying for trash. Counties cover the cost of the bags, which range from $23 to $32 depending on size, and send them to participants.

Third, "it results in fewer greenhouse gas emissions because there are fewer trucks," Garletz said. "There's not a separate truck collecting compost that needs to travel down the road and then to the facility."

With last month's four-city roll-out, the program is available to 40,000 households. As of Monday, 2,283 households had signed up.

Sam Ferguson, program coordinator for communications and outreach, said she hopes to see more people join the program.

"The higher the participation rate is of people sending food scraps, the better our technology gets," she said. The better the technology gets, the easier it will be for other local governments to adopt it.

Maplewood, North St. Paul, Cottage Grove and Newport residents can sign up for the Food Scraps Pickup Program at

The timeline for adding other Ramsey and Washington county cities hasn't been decided yet, Garletz said. Those residents can still bring food scraps to drop-off sites and can sign up for updates on the website.