A growing mountain of food waste from Twin Cities businesses and households is straining the capacity of local compost sites — a new problem for an industry that has boomed almost overnight.

The amount of compost-bound waste in the metro has doubled in just three years, state data show, as grocery stores, restaurants and thousands of residents sort more food out of the trash. Nearly all of it heads to two facilities, in Rosemount and Shakopee, which combine it with other organic matter to create nutrient-rich compost.

Those sites are running low on space to store and manage the material as it decomposes. Expanding them isn’t easy. Composting sites generally need special permits, costly protective pads, water treatment ponds and distance from nearby neighbors.

The space crunch poses a quandary for regulators hoping to divert more of the metro area’s food scraps from landfills and incinerators. Hennepin County commissioners recently voted to require many cities and businesses to recycle food waste in the coming years, but a lead staffer says there may not be a viable location in the county for a new compost facility.

The county had to scramble to find a place to unload food waste from its Brooklyn Park transfer station after Full Circle Organics, another metro-area composting site, closed in Becker in late 2016. After the state denied its request to burn or bury waste that could not be composted, Rosemount and Shakopee agreed to take more material.

“There’s an awful lot of policy out there, and the capacity has to catch up to it,” said Kevin Nordby, a co-owner of Specialized Environmental Technologies (SET), which operates the Rosemount facility.

SET is doubling its space for food waste after state regulators loosened rules on where it could be stored. But it won’t last long.

“That capacity is basically going to be full as soon as I finish the construction,” Nordby said, adding that he expects to request permission for more permitted space from the state.

The Shakopee Mdewakanton Sioux Community (SMSC) is investigating whether to expand or relocate its 25-acre facility near Hwy. 169. The facility, which is regulated by the tribal government, says it received more than 11,000 tons of recycled organic waste last year, up from about 7,000 the previous year.

Stan Ellison, SMSC’s director of land and natural resources, said the community is now turning away loads contaminated with non-compostable materials because they have enough clean material coming in. Businesses have been driving a lot of the growth, he said, in addition to new residential programs.

“We’re seeing the commercial facilities ­— grocery stores and restaurants — are more and more interested in it. And some of them have figured out how to produce a clean product,” Ellison said.

Pigs and soil

Pigs remain the top consumer of Twin Cities food waste. Hog farms gobbled up three times as much of the metro’s organic matter as the amount sent to composting sites in 2016.

Some businesses already sending food to swine, like Supervalu’s Cub Foods, have recently begun sending material unfit for the livestock — like leftover food from deli and salad bars — to compost sites.

Other groceries are looking primarily at compost. Cub franchisee Jerry’s Foods is in the process of adding organics collection to 15 stores to divert its organic waste from landfills. Twin Cities Walmart stores began sending their food waste to compost facilities in 2010.

Walmart’s organic waste is hauled by Sanimax, which also began taking organics from Hy-Vee and Fresh Thyme when their Twin Cities stores opened in recent years. Sanimax U.S. Procurement and Sales Manager Andy Barnaal said grocery stores have the most financial incentive to keep food out of the trash, since they pay additional taxes to bury or burn it.

Grants from counties accelerate the transition. That’s coupled with consulting help from the Minnesota Chamber of Commerce’s Minnesota Waste Wise program.

We’re “adding more and more businesses and everyone’s more engaged and more excited about participating in organics recycling,” said Jon Klapperich, Waste Wise program manager. “And then that lends the question of where is it all going to go?”

Curbside pickup

Hennepin County has made organics recycling a priority, recently approving a plan to require many of its cities to implement curbside pickup programs by 2022. Minneapolis and St. Louis Park have already rolled out curbside programs in recent years.

The plan said the county should explore other technologies to handle mass quantities of organic matter, like an anaerobic digester, which can operate in a smaller space.

“At least for compost sites, I don’t know if there’s any really viable sites in Hennepin County,” said Paul Kroening, Hennepin County supervising environmentalist. Kroening said space is available, but cities are reluctant to turn over agricultural land slated for future residential development.

Some say state rules make it too challenging to operate a composting facility. Full Circle Organics was evicted after the Minnesota Pollution Control Agency issued a warning letter over compliance problems, including storing paper fibers off a protective pad meant to protect groundwater from the runoff.

Max Milinkovich, owner of Full Circle Organics, said that requires another costly pad to store what he considers “nonhazardous industrial-type waste.” Full Circle’s existing 10-acre asphalt pad cost $1.7 million.

Milinkovich, now a consultant, says Minnesota’s regulations are the reason more sites haven’t opened.

“You sit down and put the regulations versus the cost of building, and what the tip fees are that you can get,” Milinkovich said. “Even with that much volume staring you in the face, it’s hard to pull the trigger.”

The state relaxed its rules around composting several years ago, but the Minnesota Composting Council has said the setback and structural requirements are still too stringent.

“They are regulating compost facilities basically almost the same as a landfill,” said Ginny Black, chairwoman of the Composting Council.

Tim Farnan, a principal planner with the MPCA, said the rules were a compromise, because others wanted stricter environmental safeguards.

“If you’re somebody who’s got a drinking well somewhere relatively near one of these facilities, how protective do you want us to be?” Farnan asked. “The answer is probably pretty protective.”

Eric Roper • 612-673-1732 Twitter: @StribRoper