To the untrained eye, the windrows that stretch across acres of prairie at the Shakopee Mdewakanton Sioux Community Organics Recycling Facility look like piles of dirt.
But each long pile is actually a carefully balanced mixture of food scraps and yard waste, blended to minimize odor and maximize growing potential.
The windrows sit untouched for two weeks. Then workers use a machine to turn the piles and help the material break down.
After 70 days, all those banana peels, coffee grounds and apple cores will be rich, black compost — ready to spread on lawns, gardens, athletic fields and golf courses.
"That is the full cycle,” said Steve Albrecht, operations administrator for the Shakopee Mdewakanton Sioux Community, which owns and operates the compost facility. “It starts in their kitchen and their yard, and then it comes here, and it goes back in their yard.”
The Shakopee facility is one of only two sites in the Twin Cities metro area that compost food waste on a large scale. The other, near Rosemount, is owned by Specialized Environmental Technologies.
Both take in tons of waste every year from grocery stores, restaurants, businesses and homes. They keep it out of landfills and turn it into a nutrient-rich product that replenishes the soil.
But COVID-19 has created new challenges for organics composting.
First, it put additional stress on the fact that Minnesota needs more places to process food waste.
The Shakopee facility is already at its maximum capacity. And when the coronavirus outbreak reached Minnesota, it sparked concerns over the safety of workers handling food waste. So the facility stopped accepting new material for about a month — and the state Pollution Control Agency granted some waste haulers a waiver to divert some organic material to landfills instead.
There’s also been another big change the past five months: Where food waste is coming from. More people are cooking and eating at home.
With schools and restaurants closed for months, that has meant a temporary slowdown in the amount of food waste coming in, Albrecht said.
"Typically, this facility does an average of 80,000 tons a year of various waste, and that includes 12,000 to 15,000 tons of food waste,” he said. “I would guess our food waste is probably going to be half that this year, maybe."
More people composting food at home is a good thing, but sometimes contamination in food waste can be a big problem. Recycling experts say it’s more critical now than ever to make sure people are putting the right items in their compost bins to make the whole system work.
The facility’s machines will sift out the bits of plastic. But ground-up bits of glass from bottles left in with food waste is harder to remove, and Albrecht said it’s just not acceptable.
"The products that we make out of the food waste are compost and things that go in people's yards, and they don't want glass in them and they don't want plastic in them,” he said. “We can't resell the product then, and so that ruins the whole recycling process if there's nowhere we can get rid of the product."
Composting at home
In 2014, Minnesota set a goal for Twin Cities-area counties to recycle and compost 75 percent of their solid waste by 2030. Waste experts say getting organic material out of the trash will be necessary to reach that benchmark.
Organic material — including food waste, soiled paper napkins and towels, pizza boxes — make up almost one-third of Hennepin County’s waste stream, said John Jaimez, organics and recycling specialist for the county.
“The only way that we’re going to be able to achieve those goals is by getting organics out of the trash and putting them to a better use,” he said.
Before the COVID-19 pandemic, about two-thirds to three-quarters of the waste going to the county’s transfer station came from the commercial sector, Jaimez said. But with more people cooking at home than they used to, he said the county has seen a shift toward more residential organic waste.
In Minneapolis, an increasing number of residents have joined the city’s organics program, including during the pandemic, with 2,000 more households signed up than a year ago. About half of the city’s households now participate, said Kellie Kish, the city's recycling coordinator.
Kish said a study of Minneapolis’ waste in 2016 found that about a quarter was organic material that could be composted. Most of that was food waste.
Getting the nutrients from organic waste back into the soil just makes environmental sense, Kish said.
“Right now, our top soil in the country is eroding faster than it can naturally replenish itself,” she said. “The only way we can really help it along is to increase the organic content of the soil. And we do that through applying compost.”
Looking for space
Organics recycling is growing across Minnesota, with dozens of cities now offering curbside compost collection programs. But Minnesota needs more places to handle all the extra organic waste.
Albrecht said the Shakopee Mdewakanton Sioux Community Organics Recycling Facility is planning a move to a different location about 10 miles away from its current site. There, they’ll be able to turn organic waste into compost more quickly using modern technology.
With more cities looking to add organics collection programs, Minnesota likely will need more composting sites like this one to handle all the food that’s thrown away.
Compost sites that handle food waste must undergo a stringent state permitting process. The pad that the waste is stored on must meet certain requirements to prevent leakage. Yard waste compost sites don’t face the same requirements.
Having an end market where the finished compost can be sold also is important, said Chuck Joswiak, sales and marketing of finished compost products at SET’s organics recycling facility in Rosemount. He said a number of organic compost sites have closed in recent years for economic reasons.
“It’s a real difficult venture if you don’t have a full program from start to finish, looking at not only the intake, but those end markets and where to bring the material after it’s been processed,” Joswiak said.
Getting it right
With more food waste now coming from homes, cities that offer organics recycling are working to educate people about what to put in their compost bins.
In Hennepin County, Jaimez said waste haulers, businesses and composting sites are trying to get the message out to people the importance of preventing contamination to keep the organics program sustainable.
“We all have our part to play, and we all need to keep this material clean,” he said. “When in doubt, figure it out. Don’t just throw it in the organics. Do a little bit of research. It’s pretty easy to find this information.”
Kish said Minneapolis residents do a really good job of putting the right items in their compost bins. A hand-sorting count of organics collection trucks in 2018 and 2019 study found a contamination rate — meaning non-compostible material in the organics waste stream — of less than 1 percent, she said.
"I really, honestly think it has something to do with our connection to nature, and that we just listen,” Kish said.
Tips for composting at home
If you’ve just started — or would like to start — composting at home, here are a few things to keep in mind, courtesy of the city of Minneapolis:
Keep a pail or other small container in a convenient location in your kitchen, such as on your counter or under the sink.
Label bins so guests know where to put organics.
Scrape food preparation scraps, leftovers and spoiled or stale food into an organics container.
Collect napkins, paper towels and other non-recyclable food-soiled paper, as well as BPI-certified compostable plates, bowls, cups, containers and utensils.
To reduce odor, keep “wet” organics such as meat and fruit peels in a container in the refrigerator or freezer.
Place organics in brown paper bags or BPI-certified compostable bags in your green organics cart once a week for collection.
Items that are OK to compost
Fruits and vegetables
Meat, fish and bones
Eggs, eggshells and paper egg cartons
Pasta, beans and rice
Bread and cereal
Nuts and shells
Napkins and paper towels
Pizza boxes from delivery
Coffee grounds and filters
BPI-certified compostable cups, plates, bowls and utensils
Cotton balls and swabs
Items that should not be composted
Frozen food boxes
Microwave popcorn bags
Fast food wrappers
Paper towels used with cleaning chemicals
Containers that aren’t BPI-certified as compostable
Recyclable items such as cartons, glass, metal, paper or plastic
Source: City of Minneapolis