A waste system in Carver Hall -- two bins and two posters -- clarifies items for recycling and items that need to be treated as trash. Photo by Christopher Gannon.
By the start of fall classes, recycling coordinator Steve Kohtz hopes to make recycling in campus buildings easier -- and more successful. Since arriving in the facilities planning and management role two years ago, his focus has been on smart, efficient recycling, which relies on separating clean recyclables from dirty or contaminated ones.
He recently wrapped up a nine-month study that tested how effectively different styles of informational posters nudge people to recycle correctly. Working with building supervisors, he'll use the results to set up "waste systems," which pair recycling and waste bins side by side and label each with pictures and words in three languages, English, Mandarin and Spanish. By the end of the month, every floor of every academic building should have a waste system: a brown or black trash bin, accompanied by a black-framed instructional poster, and a blue recycling bin, identified by a blue-framed poster.
His study during the 2023-24 academic year divided central campus buildings into three zones. The east third of campus was the control group with no changes made to indoor trash and recycling containers. He added words-only instructions in buildings on the west side and color-consistent instructional posters with words and images about what can and can't be recycled in the middle of campus.
Parks Library is an example of clients and employees making the most of the picture posters. In week 1, Kohtz said nearly 70% of recycling bin content couldn't be recycled because it was contaminated. By week 3 -- and for the duration of the study -- that fell to less than 20%.
"I want to congratulate the Iowa State community for a job well done," Kohtz said. "During those nine months, recycling actually improved in all three zones. As a university, we recycled 40 tons (36%) more than we did the previous year -- roughly the weight of a loaded 18-wheeler semitruck."
What excites Kohtz is that those 40 tons represent a growing understanding of how to recycle among employees and students. He also learned a few critical lessons. Where a stand-alone recycling bin is offered, people are likely to opt for convenience and toss in whatever they have, regardless of its potential for recycling. But offer two bins, color-code the bins and their accompanying instructions, and people are much more likely to be successful recyclers, he said.
'When in doubt, leave it out'
The most frequent offenders of contamination? Not-quite-empty coffee cups and water bottles, according to Kohtz. That's right, a half inch of water in a bottle can alter the recyclability of the contents of a bin.
In its Strategic Plan for Sustainability in Operations (2021-25), a university goal is to divert 85% of the waste it generates from a landfill or incinerator. In 2022, ISU produced nearly 4,284 tons of waste, 48% of which was diverted. Today 72% is diverted, and a focus during the coming year will be effective recycling to reach the goal.
"That's another campus accomplishment to celebrate," Kohtz said. "We have a little way to go."
An outdoor waste system: waste (black) and recycling (blue) solar compactors. Submitted photo.
Outdoor stations
While outdoor trash and recycling containers weren't part of this study, Kohtz said he also hopes to pair newly labeled waste and recycling solar compactors at seven campus CyRide bus stops in time for fall semester.
"The goal is a campus that's unified in a visual way for recycling," he said. "That consistency should help new and long-time recyclers know what to do."
Kohtz received a $9,000 grant from the Iowa Department of Natural Resources for his study. It covered printing costs for the two color-coded posters created for the study, with funds remaining for all the additional posters needed.
