Urban farms are popping up in cities across the country and are becoming notable sources of food in those communities. Urban agriculture is on the rise for a number of reasons including a lack of fresh produce in certain areas, the desire to have community-based projects and increasing interest in foods grown close to home. When food is produced nearby, the waste associated with transportation is minimized, and residents can feel good about supporting local businesses.
One urban farming technique that has been catching on in recent years is aquaponics, which is a combination of aquaculture - seafood farming - and hydroponics - growing plants without soil (often in water). One of the pioneers of this method is Will Allen, the founder of Growing Power farm in Milwaukee, Wis., and a recipient of a MacArthur Genious Grant. His system allows people to raise vegetables and fish in a small space while also allowing one species to benefit from the other.
To test out this method on a larger scale, another urban farm in Milwaukee called Sweet Water acquired some former industrial space in 2008 and built their own aquaponics system, which has garnered attention over the last few years. They supply fish like perch and tilapia and vegetables like lettuce to local restaurants, health food stores and residents. Earth911 spoke with James Godsil, one of Sweet Water's founders, to find out how exactly aquaponics works, how it can eliminate waste and how it can grow communities. Keep reading to see the three main ways an urban farm like Sweet Water can reinvent wastes we don't often think about.
1. Eliminating Agricultural Waste
How Aquaponics Works
Sweet Water believes in turning wastes into resources, and in reconsidering how we think about waste. "We're even debating whether we should use the word waste, since there's no waste in nature," James Godsil said.
To help understand how aquaponics can take waste out of the agricultural equation, let's take a look at the process.
"Aquaponics is a biomimicry experiment, meaning an innovation inspired by nature," Godsil explained. "Aquaponics mimics a wetland, river or stream. Humans strive to create conditions similar to what appears in natural ecosystems where there is a collaboration of life forms who exchange resources with one another."
A view of the aquaponics system at Growing Power in Milwaukee. Photo: Flickr/grifray
For fish and plants to exchange resources in an aquaponic system, a fish tank is built below a bed of vegetables with mechanisms connecting the two sections. Then, given the right conditions of light and heat, beneficial bacteria will also grow in the system.
Fish in the system produce waste in the form of ammonia, Godsil explained, and this ammonia is used by bacteria that turn it into nitrites. These nitrites are then converted into nitrates by another kind of bacteria. Nitrates are what plants like and what function as fertilizer in an aquaponic system. In return, the plants help filter the water to keep it safe for the fish. To facilitate this process, the water is pumped up to the plants and then drains back into the fish tank.
The system basically works as a loop, with the fish producing waste that benefits the plants, and the plants cleaning the water for the fish. The only external inputs are fish food, oxygen and, in the case of indoor systems, artificial light.
Additionally, aquaponics uses about one-tenth of the water used to grow vegetables in the ground, according to Backyard Aquaponics, which Godsil confirmed.
"It makes for the best tasting lettuce any of us have ever had," Godsil said.
Sweet Water expanded on Growing Power's idea and built an aquaponics system on a larger scale. Photo: Sweet Water
Using Wasted Waste
In an aquaculture system where fish are raised in tanks, farmers have to deal with fish waste, just as any other farm raising large numbers of animals would. Aquaponics largely eliminates this problem, since the plants will use the waste from the fish. Just as livestock manure can be utilized to fertilize soil crops at a typical farm, in urban aquaponics, fish waste can feed plants, too.
At Sweet Water, they even take using waste one step further. Some solid waste does need to be filtered out of the fish tanks, and at Sweet Water they add it to their compost pile, which they have had on site for years.
"We're making the vision of aquaponics in a city context not a fearful one because people won't have to worry about fish waste. One of the concerns about aquaculture across the world is ammonia," Godsil said.
Right now, aquaponics is a growing area for research, too, and many people are experimenting with ways to eliminate even more waste. Some experimenters hope to create soil-based food for the fish (instead of feeding them smaller fish).
"Compost can be given to worm farmers to raise red wiggler worms which can become food for the fish," Godsil said, demonstrating that when growing food, many activities can be connected. Godsil emphasized that these systems are complex, but are becoming increasingly accessible if people are interested in learning about them.
2. Reinventing Wasted Spaces
Photo: Sweet Water
Reclaiming Space to Revitalize Neighborhoods
Sweet Water started out in an old industrial building in Milwaukee's Bay View neighborhood that was formerly used for building mining cranes. When the farm moved into the empty facility, it made the building a productive use of space again and brought activity to the area. Now, the farm even plays host to local arts and cultural events, according to their website. They also offer tours to residents and visitors.
Sweet Water has also created a huge demand for its products in the community. "We can't even begin to provide lettuce or fish in the quantities that people hope we'll provide," Godsil said. "We have farmers markets and restaurants and natural food stores asking us to fill orders that we don't have the capacity to fill. There's room in Milwaukee for 50 Sweet Waters."
Learning to make aquaponics work on a large scale is an ongoing project, and the farm is currently moving some of their tanks into outdoor greenhouses next to the old factory where the plants will be able to get more light. They hope this will alleviate some of the problems associated with being located inside an old building in a northern climate, since they will have more control over the temperature.
Aquaponics systems at Sweet Water will be housed in greenhouses in the future. Photo: Sweet Water
Try It Out in Your Space
If you're interested in setting up a small aquaponics system in the space you have - perhaps your backyard or garage - it is possible. James Godsil says his farm would happily explain the process to those interested. The website Backyard Aquaponics, which explains the basics and helps visitors choose a system design and pick out fish and plants, is another useful resource.
When you raise fish and vegetables at home, you'll know exactly where your food comes from. Plus, once the system is set up and functional, the cost to maintain it decreases. You can see a variety of setups at Backyard Aquaponics, and if you're interested in using recyclable materials to build your system, that's possible, too.
3. Not Wasting Knowledge
Photo: Sweet Water
Aquaponics has some distinct benefits when it comes to dealing with agricultural waste and revitalizing urban areas. James Godsil believes aquaponics also provides a great opportunity for education. Hands-on learning can keep knowledge from going to waste.
"While we are quite certain that over the next 10, 20 or 30 years, aquaponics will prove to be of great value for food production, we are absolutely certain that right now aquaponics will prove of great value in cultivating among our young people and our lifelong learners an appreciation of all living forms," Godsil said. "Science, technology, engineering and math come alive for learners in response to hands-on learning with aquaponics."
Many people don't know a lot about where food comes from, and to take advantage of the unique educational opportunities an aquaponics farm provides, Sweet Water and their partnerSweet Water Foundation (which was originally started to accept donations of compostable materials from local food vendors, but now focuses on education) are working on many projects. Currently, they have about 40 educational programs in Milwaukee schools and 40 in Chicago in all levels of education - elementary school through graduate students, according to Godsil.
"[Sweet Water Foundation] seeks to create interdisciplinary programs that push students to become innovators, with the hope of inspiring them to pursue previously unimagined career paths or projects," says the Sweet Water Foundation on their website.
Kids learn about composting at Sweet Water. Photo: Sweet Water
The Sweet Water Foundation is even partnering with people in other countries such as India to share aquaponics knowledge. "Earth-friendly, small space, high-yield food production will be increasingly important...[Aquaponics] is of enormous consequence in arid places, which is why our global focus is so important," Godsil said.
Most recently, Sweet Water Foundation won a grant through the Digital Media and Learning Competition sponsored by Hastac, the MacArthur Foundation, Mozilla and the Bill & Melinda Gates Foundation, which will allow the farm's training programs to be made available online.
All of Sweet Water and Sweet Water Foundation's efforts help demonstrate what the farm means by it's slogan "There Grows the Neighborhood." By raising food locally and sharing their knowledge with the community, they are helping create a stronger neighborhood, too.
Want to find out more ways to participate in urban agriculture? Don't Miss: Tour de Coops Teaches Residents to Raise Backyard Chickens.
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