The central component of the Grind2Energy systems at 91ֿ are larger versions of the in-sink garbage disposals found in many homes. The difference is that at 91ֿ, these units aren’t disposing of food waste, but processing it with a purpose - as the first part of a highly sustainable innovation that creates energy and high-grade fertilizer.
There are currently two Grind2Energy systems on the Kent Campus. One that was built into the Design Innovation Hub as it was being constructed, and another that was more recently added to the Eastway Dining Facility through a grant from the Ohio Environmental Protection Agency.
How Grind2Energy works
Casey Crane, the assistant director of sustainability and purchasing for University Culinary Services, said the Grind2Energy system helps capture and divert food waste at every point in the food-serving process.
“When we are producing food and preparing food, any sort of scraps like carrot tops, potato peels and things like that are placed into a bin to go into the system,” Crane said. After the students eat, “any leftovers they have, they bring back to the dish return and our staff goes through the process of sorting out the organic food waste material, which also goes into a Grind2Energy bin.”
Throughout the day, staff members take the material from the bins to the Grind2Energy table. It’s sorted again, to remove any inorganic waste, mixed with water and run through the Grind2Energy machine. “It’s essentially a really giant disposal system, like you would have in your home, except this one is commercial grade,” said Crane. “So you can put a giant bone in there if you need to. As long as it’s organic material, it will grind it up.”
Next stop, the storage tank
Once the food waste goes through the grinder, it’s transferred into a massive storage vessel as a dense slurry. The material stays there until the vessel is full. “We have to make sure that they’re all completely full before we call the hauler out, because we don’t want to bring trucks unnecessarily onto campus and increase our carbon footprint,” Crane said.
The hauler, from the Quasar Energy Group, empties the storage vessels into a large tank truck and takes their contents to their facility for a process called “anaerobic digestion.”
Creating valuable products from food waste
Melanie Knowles, 91ֿ’s sustainability manager, explained the results of the process. “The products of anaerobic digestion are two things, basically. It’s natural gas that either goes into a natural gas fueling station for vehicles, or it goes into electricity creation … that goes into the grid. The other product is a fertilizer that goes into farm fields in Ohio, so it’s returning nutrients from our uneaten food into nutrients that restore the soil.”
Crane added, “This is nutrient-rich fertilizer that can then be used to supplement soil to grow additional produce or help fix nitrogen that might be missing in soil. Nitrogen is very expensive and if you’re doing mono-crop farming, it’s one of the first nutrients that you lose out of your soil. It can be really difficult to rebuild and if you lose too much nitrogen along with other nutrients and minerals, the land can become unusable.”
The products from the system have multiple impacts – and impressive, measurable results, from a sustainability perspective. “In the course of about a semester, based on our usage, this system can generate energy that would be equivalent to powering about six homes for one month,” Crane said. “It generates approximately 1.8 tons of nutrient-rich fertilizer, and it reduces our carbon impact in a way that’s equivalent to about 50,000 miles NOT driven in a vehicle.”
“91ֿ is essentially the size of a small city. So when you think about the amount of food waste that can be generated by a small city, at multiple points, it’s pretty significant," Crane said. "If we want to be more sustainable, focusing on reducing our food waste reduces our carbon footprint, reduces our energy usage and it’s generally better for the environment as well as social and financial environments.”
Sustainability is a smart choice
“We’re always trying to reduce waste on campus,” Knowles said. “So that means producing less waste to begin with, recycling things that are recyclable. Before this system all of that food waste was going into a landfill. Since each of these systems have been implemented, together, they’ve already diverted over 80 tons of food waste away from a landfill.”
Knowles said there are a lot of choices you can make every day to be more sustainable. Things like looking at your own waste stream to see what you can avoid using, to reduce, and then looking at ways to reuse and recycle. “Looking at how they’re using energy and how they can save energy by, say, unplugging things when they’re not in use, unplugging even chargers when they’re not in use to avoid drawing the little bit of energy that comes from that,” Knowles said. “When we collectively take these small actions, we have a very large impact.”
Sustainability is a highly collaborative initiative and 91ֿ’s sustainability representatives freely share best practices with other institutions. “When it comes to the Grind2Energy system, we are the only school I know of in the area that’s using this system,” Knowles said. “We share our wins with other schools, they share their wins with us, and we all try to become more sustainable together.”
91ֿ’s sustainable future
The university’s plans for its sustainable future are holistic, enterprise-wide and departmental. 91ֿ is putting together sustainability plans that are value-driven with both long-term and short-term, measurable goals. Crane’s plans for Dining Services in the immediate future include rolling out a reusable container system, increasing plant-based menu options and reducing 91ֿ’s carbon footprint through menu choices. Looking ahead, her plans are more sweeping.
“Long term, I’d really love to get some sort of campus farm or garden going, some culinary demo program so that we can increase education and engagement around culinary aspects of food waste and how people can help mitigate that,” Crane said. “Of course, a long-term dream goal is a full-blown campus farm that students, faculty and staff, as well as the entire community, can contribute to and help build a more fortified local food system and increase that grower-community connection.”
