U of I, Kootenai Tribe partner on large-scale composting project

University of Idaho’s Sandpoint Organic Agriculture Center (SOAC) has begun a collaborative demonstration project to mass produce nutrient-dense compost from locally sourced kitchen and lumber waste.

SOAC staff are partnering with the Kootenai Tribe, Schweitzer Mountain Resort and Stimson Lumber to fill a community need for high-quality compost while diverting waste from the county landfill.

SOAC began large-scale compost production in January 2026, using food waste from the kitchens at Schweitzer blended with pine, fir and spruce planer shavings and bark from Stimson to make a finished product with a good balance of nutrients and carbon.

Within its first 28 days of operation, SOAC’s system, which is housed within a 20-foot-long storage container, processed 2,746 pounds of food waste. The unit has the capacity to produce up to 200 tons of finished compost per year. Eventually, SOAC may expand the composting program to accept waste from other community eateries.

“One of the things that led us into composting is our advisory board here at SOAC — which is made of agricultural educators, farmers and ranchers in the area — identified the need for a local, high-quality compost source,” said SOAC Superintendent and Orchard Operations Manager Kyle Nagy. “We’ll be using the compost in our educational market garden, but our long-term plan is to offer it for sale to the community, so we have a local source of compost.”

Green Mountain Technologies based in Bainbridge Island, Washington, manufactured SOAC’s Earthflow composting system. It has a vertical auger to mix waste, nozzles to spray the contents with mist and aerators to promote decomposition — a process that naturally generates heat.

Waste remains in the composter for up to three weeks and must heat to at least 131 degrees for three consecutive days to kill any pathogens. After being removed from the vessel, compost is cured in a barn for another four to six weeks before it can be applied as a soil amendment.

Rather than making compost one big batch at a time, SOAC staff continuously move food waste through the system, adding a bit more waste to the container as finished compost is removed.

The project was funded with part of a three-year, $530,000 grant the Kootenai Tribe received from the Environmental Protection Agency’s Solid Waste Infrastructure for Recycling (SWIFR) program, which is intended to improve recycling and waste-management infrastructure throughout the U.S. The Tribe wanted to lessen the impact of food waste on the county’s overburdened landfill and approached SOAC about cooperating to promote environmental stewardship. The grant also supports various Tribal conservation efforts, including a project to allow Tribal members to recycle and compost using small, in-home composters.

“The whole focus there at SOAC is in line with the stewardship effort of the Tribe and offered a nice partnership with what we wanted to get done, as well as with education and making a difference on the landscape,” said Karen Schumacher, environmental program manager with the Kootenai Tribe.

The Tribe will contribute food waste from its enterprise operations — including The Springs Restaurant and Sonic Food Station — to SOAC on a trial basis beginning in spring 2026.

“The reports Tribal Council have received are that everything is going great,” Schumacher said. “SOAC is doing a phenomenal job, and the Tribal Council is pleased to hear that.”

With the funding provided by the Kootenai Tribe, SOAC made roughly $50,000 in infrastructural improvements to an old storage building to house the composter. Among the upgrades, SOAC installed reinforced concrete pads to support the unit’s weight and equipped the building with water and electricity. Each unit costs roughly $100,000.

“Part of the Tribe’s desire for this project is to have it be a demonstration site to show other communities of our size what’s possible for composting,” Nagy said. “This is something that could be replicated in small towns all over the region to help remove food waste from their solid waste stream.”

SOAC Assistant Operations Manager Kent Youngdahl oversees the composter’s daily operations. Youngdahl, who earned a bachelor’s degree from U of I in sustainable food systems in 2020, recently enrolled in a U of I master’s program in soil and land resources and intends to use his work with the composter as the basis for a master’s project.

His goal is to someday start his own composting business or work as a consultant specializing in composting.

“The part that interests me the most is seeing how much food waste you’re able to divert and produce into a sustainable project,” Youngdahl said. “Something that was originally going to get thrown into a landfill can get reused in a product that’s going to promote soil health.”