ISU Dining integrates vending misers to save energy, cut costs

Elisse Lorenc

The ISU Dining Sustainability Green Team is taking a variety of initiatives to become more sustainable in the dining centers, including a composting program and vending misers.

“A lot of that post-consumer waste used to actually get ground up in the garbage disposal and go down the drain,” said Nancy Levandowski, director of campus dining services. “The city of Ames used to heavily treat the water because of the food particles in it, and they started charging us, and that was why getting that revolving green fund out front was beneficial. We got to stop paying the city for water treatment.”

The composting program is still relatively new on campus, but allows students to discard their own trash without having to throw it down the garbage disposal. The program focuses predominantly on the three dining centers and includes both post-consumer and pre-consumer waste.

“Pre-consumer waste — like the top of a carrot, the peels from a carrot or the peels from a potato — those get composted, and then all post-consumer waste gets composted, said Chantal Roberts, sustainability chair for ISU Dining. “Whatever students leave on their plates, they get basically put into the pulper, which breaks down the material into smaller pieces. It’s easier to decompose, and then that’s taken to the dumpster outside of each of the three dining centers, and that’s taken three times a week and brought to the dairy facility, and from there it’s composted and sold back to ISU to be used on campus.”

The pulpers grind the food and drain any excess water, when it’s then dumped into buckets to be taken to the dumpsters. The machinery is currently located at Seasons, Union Drive and Oak-Elm dining centers.

“We reduced the amount of trash can size that we had,” Levandowski said. “One of the things that we found is that we have a lot more trash from Clyde’s than we realized because of all the paper supplies and things that people use there.”

The team’s next step is the Memorial Union, which has proven to be easier said than done.

“With the Memorial Union, we haven’t quite figured out the logistics just because the loading dock area and the trash area is, obviously, heavily used,” Levandowski said. “We haven’t quite figured out how potentially we could do that there yet, and we’re still trying to work through options right now.”

The vending misers are a way to conserve electricity within the soda pop machines.

Vending misers are motion-sensitive and conserve energy that lights the machine as well as temperature. With its motion sensors operating inside the vending machine, it will shut down and fluctuate to lower temperatures until it detects motion when a student may approach the machine.

“They’ve got a lot of marketing going on with the lighting for the pop machines, and so they’re the ones that are using a lot more of the energy, so it makes sense to put it where it’s going to have a better reduction of the energy use,” Levandowski said.

The vending misers have saved a total estimate of $12,750, said Bob Parrish, assistant manager in food services.

“Because it’s low maintenance, it has not proven to be detrimental to the pop machines we have monitored,” Parrish said.

The soda machines, Parrish said, are a good place to start for the vending misers, considering the abundance of them. If ISU Dining gets more funding, Parrish speculates its next project would be the non-refrigerated snack machines.

The vending misers are a wise investment, and after observing the misers for a few weeks, the outcomes were satisfactory, Parrish said.

Without the miser, Iowa State had energy costs of $3.65 per week per vending machine at Student Services. The following week with the miser installed, it cost $1.25 to run the soda machine, Parrish said.

“When you’re talking per machine per year, it does translate to money; you start talking the number of machines we have, it adds up to $13,500 a year, which is significant.”

As a future goal, Levandowski wants to introduce a “buy fresh, buy local” program for students on campus.

Roberts hopes to get more of an outreach to students, possibly using booths as a good visual to draw attention and answer any questions.

“We’re working in lots of different areas trying to create a cohesive group, working together definitely is key, which we already do very well, it’s just moving together forward and making goals for ourselves,” Roberts said.

For more information on the ISU Dining Sustainability Green Team and the programs they involve themselves with, check out their blog at