Bangor high school students helped the city turn yard waste into usable compost that can be returned to residents — and won a science fair in the process.
In October 2023, Bangor High School students Nora Lin and Rowan Osmer collected samples of two-year-old compost made from leaves and yard debris the Bangor public works department collected from residents.
The students spent this past winter testing the material for pesticides by tracking the growth of bean plants that had been planted in it, said Aaron Huotari, Bangor’s public works director. The plants’ growth was compared with ones grown in commercial grade fertilizer.
The city also sent a sample of its compost to the University of Maine Analytical Lab to ensure the soil had finished breaking down, Huotari said.
The students’ work showed the city’s soil produced plants nearly as healthy as the commercial product, proving Bangor’s version isn’t tainted with pesticides. The compost will be returned to residents to use in their gardens for the first time since the city launched the project.
“Our compost held its own,” Huotari said. “I’m extremely pleased with the work the students have done.”
Lin’s testing findings won first place in the Maine State Science Fair “plant sciences — other” category this year.
Before Huotari joined the public works department, the city attempted to make compost for residents from yard waste, but it was too expensive to test for pesticides. Without the test, residents were hesitant to use the soil.
When Huotari stepped into his role with the city, he was interested in restarting the program with the goal of giving the material back to residents.
“My goal was always to make compost again, I just didn’t know how I was going to do it,” Huotari said. “I knew I needed to address the pesticide concern we had in the past.”
Huotari attended the Maine Compost School where he learned about the testing process, called bioassay, that’s a simpler but valid way to assess the material. Rather than perform the analysis alone, Huotari reached out to Bangor High School’s STEM Academy to see if any students were interested in performing the study.
The bioassay process involves looking for the effects pesticides will have on plants, such as making the leaves curl, Huotari said. The plants’ health is also measured by looking at the density of their roots.
Lin and Osmer’s projects reveal how something as mundane as fallen leaves can be turned into something positive for a community, said Dr. Barbara Stewart, Bangor High School’s Science, Engineering and Technology Department chair.
As a Bangor resident, Stewart said she previously wondered what happened to her yard debris after city public works crews whisked it away.
“I love that this project follows the process of it getting turned into usable soil,” Stewart said. “That testing is such an important part of that process because it gives you confidence in the product.”
Now that the city’s compost has passed the necessary tests, Huotari is looking to rent a screening machine that will remove large objects, like sticks and rocks, from the soil.
After the soil is cleared of debris, Huotari hopes to hold pick-up days in the coming weeks where residents can take up to a truck bed-sized load of compost on a first-come-first-served basis.
The city now plans to continue this testing annually using the process the Bangor students piloted. Bangor High School science teachers are also looking to incorporate the tests into their curriculum, Stewart said.
“Our goal isn’t to be a commercial composting operation,” Huotari said. “We just want to make more passive use of the materials we have.”
