With new biodigester, students in Columbia Heights schools get lessons on sustainability

Leftover lunch is hardly going to waste at an elementary school in Fridley, where a new machine is turning table scraps into clean-burning fuel to heat the building and compost material to help gardens grow.

Called the biodigester, the system is the latest addition to the curriculum centering on science, technology, math, creativity and sustainability at North Park School for Innovation.

"It's a real good message to get across to our kids," said Principal Jeff Cacek. "We want our kids to understand about sustainability. We owe it to them to give them tools and teach them."

North Park, part of the small Columbia Heights Public School District, is believed to be the first school in the U.S. to get a bio­digester, after a former superintendent heard about it at a dinner party and worked with manufacturer Waste to Energy Canada to donate the biodigester and a biomass boiler to the school.

Students and staff dump their uneaten food into a bin that is emptied into the biodigester. The waste is heated to more than 150 degrees and broken down in 12 to 24 hours. When done, the digester spits out a dark mulch-like nutrient soil additive that's tilled into the school's rain and courtyard gardens and used as fuel to power the boiler.

"It looks like coffee," said Lincoln Bolitho, a North Park fifth-grader. Though he doesn't like the smell, he thinks adding the biodigester was a good idea. "It helps with food for plants."

The system reduces mass and volume of organic waste by up to 70%, said Kim Shelquist, director at Waste Water Panels, a Minneapolis environmental company providing support.

"It will more than pay for itself," Shelquist said, noting it costs about $7 a day to operate the digester.

North Park, serving about 400 students in prekindergarten through fifth grade, began its green movement several years ago. It started simple, with reminders for students and staff to turn out lights to save electricity. Then the school was the first in the district to try composting in its cafeteria. Next came 84 solar panels attached to the roof. In 2018, North Park was designated a Green Ribbon School, an honor given by the U.S. Department of Education to schools that reduce their environmental impact, improve health and wellness, and advance school sustainability.

Students will get a crash course on how the biodigester works when school resumes this fall, Cacek said. But they are already learning about the importance of composting and thinking about actions they can take to mitigate climate change.

Bolitho said people should plant gardens and wildflowers, use cloth bags at the grocery store and bike more. Oscar Kokes, a North Park fourth-grader, said people should switch to electric-powered cars and ride public transportation more.

"We should be doing everything in our power to stop doing what we are doing to planet Earth," Kokes said. "Climate change is real and it affects all of us."

The biodigester will be another learning tool for students as the school continues to look for ways to show the role engineering will play in shrinking carbon output at a time when concerns about climate change are growing, Cacek said.

"They will be the problem solvers of the future," Cacek said. "We hope students go home and teach their siblings and family that this is worth doing."

Kokes said his family already composts at home and that he picks up trash in his neighborhood. His message to those who don't recycle, compost and care about the environment was pointed:

"Start it now."

Tim Harlow • 612-673-7768