By Eve Daniels
When someone mentions “food security,” eggshells and banana peels may not be the first things that come to mind. But to Larry Baker, a research professor in the Department of Bioproducts and Biosystems Engineering, our food waste could be the key to a happy and healthy future.
As part of the MnDRIVE-funded Waste Not project, Baker and his fellow researchers are working to close the loop on our organic waste systems. By finding ways to transform these systems, they hope to reduce the cost of disposal, as well as the environmental impacts of food production.
Tapping into the full potential
In the U.S. alone, 40 percent of our food goes uneaten, according to a 2012 report by the Natural Resources Defense Council. That’s like throwing away about $165 billion each year. Meanwhile, the uneaten food rots in landfills, adding up to a large portion of the country’s methane emissions.
Right now, food waste accounts for more than 20 percent of total municipal landfill waste. Until recently, most of this waste in the Twin Cities was landfilled directly or incinerated and then landfilled, otherwise known as a “flow-through” system. But as landfills reach full capacity, cities across the U.S. are moving toward a more sustainable, closed-loop system.
Participants in the Waste Not project envision an economy in which we use and benefit from organic waste, rather than simply burying it. Some potential uses include renewable energy, animal feed, and fertilizers.
Feed and fertilizer
Beginning in 2014, researchers from seven academic departments came together with technical advisors from the city, county and state. The project collaborators started by collecting food waste samples from Bailey Hall on the St. Paul campus, Lunds & Byerlys on Snelling Avenue, and a few other local sources.
After drying the waste in an oven, grinding it up, and getting it into powder form, the team was able to analyze the waste for both animal feed and biofuel potential.
“We were thrilled by looking at the actual nutrient content of the food waste,” says Baker. “It’s more of a valuable resource than we originally thought.”
Turns out, our food scraps could provide a nutrient-rich feedstock for swine and other livestock. In fact, the researchers found that urban organic waste is comparable to corn and soybean meal in both calories and protein.
Moreover, when that feedstock is blended with other ingredients, the resulting feed could be worth somewhere between $200 and $300 per ton. “Currently, the price of feed is more than half the price of raising a hog,” says Baker. “So there’s a particular value in feeding hogs.”
The researchers also discovered that urban biosolids, when turned to ash, work well as a fertilizer—providing yet another way to close the loop.
Although it could take a decade before we bring these products to market, Baker believes it’s inevitable. Along with energy and environmental issues, a closed-loop system could help us to avoid geopolitical problems.
Phosphorus, which is used in fertilizer production, offers a good case in point: “Right now, phosphorus is very sparsely distributed, with about 75 percent of the world’s supply in one country: Morocco,” explains Baker. “As we’ve learned from our experience with oil, it’s not a question of ‘how much is there?’ but rather ‘where is it?’ So by recycling it from food waste and biosolids, we’re buying some political stability.”
As they move into the next phase of the project, the Waste Not team hopes to get more funding to continue their research.
“If we’re going to re-engineer the whole country, we’re going to need a lot more research,” says Baker. “If we don’t do it, we’ll end up making a lot of mistakes that we regret later.”