Trash compactors continue to save some green


This solar trash compactor near The Hub is in one of campus' busiest locations. Photo by Christopher Gannon.

Seven years after their debut, the green, solar-powered trash compactors dotted across campus continue to take big bites out of facilities planning and management's operating expenses while also making campus more sustainable.

FPM placed the first compactor west of busy Curtiss Hall in 2009 and periodically moved it to other heavy-traffic areas on campus to determine if it could help save time, money and labor costs. The results were positive.  In 2008, before solar trash compactors were part of the campus landscape, FPM spent $35,723 on litter removal, according to Merry Rankin, director of sustainability programs. By 2015, that number had decreased to $19,846.

Today, 96 of the Cy-emblazoned green containers are in place with another 20-plus ready for installation by December. Iowa State's Student Government funded 47 of the most recent compactors at a cost of $4,760 each.

"Of the many things Student Government could support, it was very exciting and motivating for the sustainability movement at Iowa State that they chose to put that money toward the solar trash compactors," Rankin said.

Big impact

With the installation of each solar trash compactor, three concrete-encased metal trash bins are removed from campus. By the end of the year, Rankin estimates only about 25 of the original 300 concrete bins on campus will remain, all near residence halls. In true sustainable fashion, the bins go to asset recovery as they are removed.

"It's our intent that they be reused in their current form," Rankin said.

Fewer concrete trash bins means FPM will save money and increase efficiencies. Why? Trash compactors take the guesswork out of determining when to collect the garbage. Electronic "eyes," activated by solar panels on top of the compactors, monitor the trash depth. A flashing light indicates when a container is full and triggers a wireless monitoring system that alerts FPM staff via computers to empty the compactor.

Not knowing if concrete trash bins are full requires FPM to send large, gas-guzzling (8 miles per gallon) trucks to collect garbage daily. Instead, knowing exactly which solar compactors need dumping requires only small utility vehicles, which consume about 5 gallons of gas per week.

In addition, Rankin said while FPM employees are picking up trash from the compactors, they can work on other projects -- like tree trimming.

"This supports social sustainability by making the most efficient use of our teams' skills and expertise," Rankin said.

Another advantage of the solar trash compactors is that they are fully enclosed. That means no unwanted visitors (think birds, squirrels, raccoons) can get in them and drag garbage on the ground, saving FPM more time and money.

Future funding

Besides Student Government's funding of the latest compactors, typical purchasers are FPM, the department of residence and the office of sustainability. However, Rankin encourages other units to consider funding them as well.

"There may be other partners on campus who want to come forward. That would make the environmental and economic impact that much greater," Rankin said.

Related story:

High-tech trash, Aug. 27, 2009