ISU Dining supports sustainability, composting


Photo: Shuyang Qu/Iowa State Daily

The facility takes charge of taking all the compostable wastes from campus and turning it into a reusable substance for soil.

Jasmine Qu

ISU Dining continues to be an active proponent for sustainability on campus through its composting system. It saves food waste in the dining center from landfills by making it into nitrogen-rich soil supplements. 

“[The] compost system is important because it’s sustainable. Our university is driven towards the Green Movement and trying to find sustainable ways of living,” said Cameron Aisenbrey, communication specialist for ISU Dining.

The facility composts both pre-consumer and post-consumer wastes. At the dining centers, post-consumer wastes go through the dish line where employees sort out waste. Everything that is compostable goes though the pulper, a machine that runs through water from wastes, condenses it down and makes it solid to the bottom of the pulper and then into the trashcan.

Wastes in the dining centers consist of pre-consumer waste and post-consumer waste. Pre-consumer wastes are materials that were discarded before they were ready for consumer use, such as carrot tops or potato skins.

Also, the napkins ISU Dining uses are made of a natural material that chemically breaks down when it is composted. 

What happens to the compostable wastes after they are dumped into the compost trash bin? The compostable wastes are taken to the ISU compost facility at the Research Farms located southwest of Ames. 

Inside the ISU compost facility are seven huge hoops for storage of the compost.

“You stand here, you can smell it, but it’s not like oh-my-god overpowering,” said Steve Jonas, manager of ISU compost facility. “That’s because you have right ratio of carbon-nitrogen, moisture and good poor space of oxygen. Everything should be working right to break down.”

The first step in composting is to take the materials from the waste hoop, according to Jonas. The waste is put into a dump cart or a wagon and taken to another hoop to mix the materials with corn stalk, leaves and manure from the ISU Dairy Farm, which is located nearby.

After that, the waste is laid our in long, narrow piles called wind-rows and is turned and aerated periodically until the whole process finishes. During this time, microorganisms in the mixture start to work by themselves.

“We are looking for a good carbon-nitrogen ratio, you want a ratio [so] that microbes in the manure just occur naturally. When you get the right ratio, it starts to break the materials down right.”

As it breaks down, it gets smaller and smaller while the smell gets lighter and lighter. The whole process from start to finish takes about 16 weeks, When it is ready, the straight compost can be mixed up with different ratios of different soils or other materials to make it specific for different grasses, trees or other plants.

Now it is ready to be mixed. The compost is then blended with sand and soil, and the amended soil is used for landscaping new construction projects, existing buildings, and planting beds.

“When the university compost facility site was built, it gave us and a number of people in the area an option to, instead of wasting food or putting everything to garbage, give it to them and have it returned to campus,” Ainsbrey said. “It’s an opportunity to reuse that, and be more sustainable with our food waste.”

The facility has also been approved for wholesaling, so it also sells the compost to state nurseries and private companies such as those for landscaping.