Closed-loop production systems offer farmers an efficient method for growing food and produce while significantly reducing the waste associated with traditional methods.
In Wisconsin, heated aquaponics systems allow producers to grow fish and plants even during the winter. But even though such systems reduce traditional waste, do they still have adverse environmental impacts?
Andrea Hicks, an assistant professor of civil and environmental engineering at the University of Wisconsin-Madison, is tackling that question thanks to a prestigious National Science Foundation CAREER Award. She received the five-year award of nearly $500,000 under the NSF’s Division of Chemical, Bioengineering, Environmental and Transport Systems.
Hicks will use life cycle assessments to study the environmental impact of aquaponics—and in particular, the method’s carbon footprint—by working with aquaponics producers across Wisconsin and with the University of Wisconsin-Stevens Point, which raises fish such as walleye.
Aquaponics systems combine aquaculture and hydroponics. Fish live in tanks, where bacteria remove and break down their waste. That process produces nutrient-rich water which then cycles to plants such as lettuce that feed on the nutrients, and in the process, clean the water before it’s returned to the fish tanks. It’s a circular system with dramatic waste reduction potential.
“Typically, things run in a linear system with inputs, outputs and waste products at the end,” Hicks says. “Aquaponics, however, is a really efficient method for agriculture in that you don’t have things like runoff and you don’t have as much water loss.”
Beyond its potential as a sustainable agriculture method, aquaponics enables farmers to raise fish in places where it would otherwise be impossible—for example, raising Atlantic salmon in Wisconsin. However, Wisconsin’s cold climate comes with a challenge: Aquaponics systems must be heated for long stretches of the year, and that introduces extra environmental impact.
To determine the extent of that extra impact, Hicks will look at the factors that go into aquaponics systems—how much feed they use, or the types of fish and plants produced. She’ll study energy inputs, including how much and what types of energy different aquaponics systems use. For example, some use natural gas for heating, while others are heated by firewood.
Hicks’s analysis won’t stop with the aquaponics systems themselves. Aquaponics producers can send their fish to market from locations where the fish isn’t naturally available. That can, in turn, lead to shorter transit routes from producers to markets, which could have a beneficial impact on carbon emissions.
“If we can grow food here in Wisconsin and it’s used in Chicago, how does that compare to seafood that’s coming from the coast?” she says. “The food transportation impact is something we’ll look at as well. It’s an environmental and economic impact.”
As part of an educational and public outreach effort associated with the CAREER Award, Hicks will work with Vincent High School, an urban agriculture school in Milwaukee, to restart its aquaponics program. She’ll also work to create an app to help aquaponics producers across Wisconsin and, potentially, the Midwest calculate their carbon footprint and environmental impact.
“This is using data they already have,” she says. “They know how much food they buy, how many fish they produce, and how much water and electricity they use because these are things that affect their bottom line. It’s about empowering them.”
Author: Alex Holloway