A Tour of the Minneapolis Composting Program – Mpls.St.Paul Magazine

a-tour-of-the-minneapolis-composting-program-–-mplsst.paul-magazine

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Turkey vultures, seagulls and eagles circle overhead as trucks form small mountains of food scraps at Rosemount’s organics recycling facility. Jake Duame, who has monitored the food waste brought here from Minneapolis for years, points out a pile of freshly delivered material dotted with rotting pumpkins and apples. 

“In a couple months, we’ll start seeing the Christmas trees,” he says cheerfully as we walk across the 4-acre site where organic waste sits at varying stages of decay, undergoing its transformation into soil saving compost. 

Since Minneapolis’ curbside organics recycling program rolled out in 2016, over half of the city’s households have ordered a small green bin to sit alongside their recycling and trash bins, where they can toss banana peels, bones, nail clippings, pizza boxes and more.

Recycling coordinator Kellie Kish says 20-30 new households sign up for a bin each week, which is free for those with City collection service (If your trash bin says “Property of Minneapolis”, that’s you).

The curbside organics program alone collects more than 6,000 tons annually which gets hauled down to Specialized Environmental Technologies’ Rosemount facility—one of only two sites in the state that composts food waste on a large scale.

Here, bulldozers start the process by blending together ground up yard waste and food waste. Like a monstrous cake, yard waste acts as the dry ingredients and soggy food waste is the wet ingredients. That mix gets pushed into a long pile that sits atop a 200 ft aeration tube. “Essentially a souped up leaf blower,” explains Duame. “It’s a thick walled cardboard tube that we poke holes into to release oxygen throughout the pile.” 

Oxygen riles up the microorganisms within and as the internal temperature jumps as they get busy breaking down everything from egg cartons and chicken bones. Composting permits mandate that the piles stay above 131 degrees for at least a week to destroy pathogens like salmonella, weed seeds and invasive insect eggs. Duame checks the mega thermometer poking out from an older pile on-site, which is cooking at 164.

“In the winter when you break into these, you see steam just billowing out from the piles,” says Duame, who will come to work after a heavy snow to see a blanket of white across everything but the brown compost piles. 

Workers break down the oldest row of the lot, which is bound for the “curing pile” after undergoing a screening for contaminants. It sits in the curing pile, which wraps around the perimeter of the site, for 6-9 months. Trucks toss the stuff around every now and then to wake up the microbes and spike the temp but gradually those spikes decrease – which is ideal, as a steaming bucket of compost can burn plant roots if too biologically active.

Mysteriously, fully flattened silverware lies scattered across the impervious pad where the compost rows cook before the curing stage. “Probably from school cafeterias with reusables,” Duame guesses as we walk past our tenth fork toward the three-armed star screener – the final step in the production process. 

Material brought over from the curing pile rushes through the three-armed star screener and the first arm spits out contaminants that made it this far, like shiny bits of snakeskin from plastic lined cups. The city's program does boast a contamination rate of just 1%, so low that other cities with similar programs look at us with suspicious disbelief.

Chunks of unprocessed woody material get dished into a second pile while everything else—the good stuff—swiftly runs up a conveyor belt onto a rich black mountain of compost. Though a beautiful sight, the wind pummeling us with fine particles of the good stuff makes it hard to marvel for too long. 

Much of that pile will go to new construction projects. “After a building or parking lot or a road gets built, all that heavy equipment driving back and forth on that soil just totally destroys it, packs it all to hell. So adding compost to that really helps,” Duame says.

Because this compost’s organic matter and microbial activity breathe life back into depleted soil, local farmers will apply it in place of synthetic fertilizer on their fields. The state will use some for wetland restoration and erosion control. In return for providing copious food scraps, Minneapolis also gets 600 cubic yards back annually to spread across community gardens. 

Despite this waste’s fairytale ending, the ultimate goal of waste management is to generate less of it in the first place. Though it's all compostable, Duame can’t help but feel flustered when an event center sends a dozen rolls of brand new toilet paper along with their used paper towels, just because it wasn’t used during that night’s event.

“Grocery stores also send us tons and tons—literal tons—of perfectly good food just because they need to get it off the shelves so they can put out more,” Duame said. “I just wish the stores themselves were more efficient with how they do things but if it falls to us, at least it's not going to a landfill or an incinerator.”

Kish, who always has some compost from SET on hand, will use it to plant milkweed seeds in her yard. “They need the hard freeze to actually germinate so I’m gonna go lay those out today and cover them with compost so they dont blow away.”

All of Minneapolis’ residential trash ends up at the HERC incinerator downtown and our nutrient-dense, water-dense food scraps don’t burn well at all. If you live in a residential building with four units or less, you likely have City collection service and can sign up for your own green bin here. Or, use this handy guide to make your own DIY composting operation. 

Apartment dwellers: check how close you are to one of the city’s 18 drop-off sites with this map. For those not in Minneapolis, look into your local organics offerings. 

Within our slew of systemic and existential trash issues, composting makes an impact. Kish hopes it shakes people up from out-of-sight, out-of-mind attitudes toward waste. “Talking trash is fun!”

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