Extension Specialist Brings Aquaponics to ISU and Beyond

By: Nicole Onken, CALS Communications Service

Imagine a world where humans can create an almost entirely self-sustaining agricultural system and use it to produce food faster and cheaper than ever before.

Now imagine that system sitting in the first-floor lounge of Science Hall II.

That is essentially what Allen Pattillo has done with Miniponics 3.0, his latest aquaponics project.

Allen Pattillo stands next to Miniponics 3.0, an aquaponics system he built with his undergraduate assisstant Sophie Rotole.  Photo by Barb McBreen.
  Aquaponics 101 “An aquaponics system is a combination of aquaculture, wastewater treatment and hydroponic crop production,” said Pattillo, a fisheries and aquaculture extension specialist in the Department of Natural Resource Ecology and Management.  

Aquaponics uses bacteria to break down leftover fish waste and transform it into nutrients for plant growth. “The most abundant nutrient is nitrogen, which promotes green growth. Thirteen macro and micronutrients are needed for plant growth and the fish feed provides all but three. The others come from the source water and supplements,” said Pattillo.

The fish wastewater is then pumped to the plants, which absorb the nutrients, making the water cleaner for the fish when it is returned to their tank.

Pattillo says the benefits of an aquaponics system are more efficient plant growth and less waste, along with the ability to produce food year-round. Plants grow roughly twice as fast compared to traditional soil methods. He says the produce tastes fresher and has a more intense flavor compared to store-bought. They can also be grown in a much more compact area due to the abundance of nutrients in the recycled fish wastewater.

“Based on current hydroponic produce prices at the supermarket, in a year’s time you could save yourself about $650 if you only ate aquaponically grown lettuce. If you’re growing basil or other herbs, we figured you could probably save yourself over a $1,000 a year,” said Pattillo.

Leafy greens and herbs tend to be the best plants to grow, because they thrive off the nitrogen-saturated water, Pattillo says. However, he adds that many other plants and fish could be used in aquaponics. Most fish will also do well, as long as they are suited to the water temperature and quality. Pattillo has used green sunfish, fathead minnows and zebra fish. He says tilapia and barramundi also work well. For optimal results, Pattillo also recommends choosing fish that will eat pelleted food.

Miniponics 3.0
Pattillo’s Miniponics 3.0 system represents a closed-loop agricultural cycle that is almost entirely self-sustaining. This aquaponics method is modeled by a wooden structure that houses a large glass fish tank on the bottom and plastic black bins on top. The bins are filled with expanding clay media for the plants to grow in. Electricity powers LED lights to for plant growth, along with a water pump and aerator to keep the water circulating through the system's tubes. 

Miniponics 3.0 is located in the first-floor lounge of Science Hall II. Photo by Barb McBreen.

The only maintenance Pattillo does is to feed the fish pellet food, clean the fish tank and occasionally add back the water that has been lost to evapotranspiration. The entire set-up was built with materials readily available in Iowa hardware stores – roughly $400 worth.

Pattillo’s version is a small-scale system, but aquaponics can be sized up or down, from small gallon tanks at home to larger operations.  

“The technology scales up to even a commercial scale, where you can produce and grow under acres of greenhouses,” said Pattillo.

While Miniponics 3.0 seems fairly advanced right now, it took a lot of trial and error to get there. Pattillo and his assistant, Sophie Rotole, a junior in agricultural engineering, did a few different versions before settling on the 3.0 model. After extensive research, including hosting a Miniponics 2.0 ISU Extension workshop and surveying the participants about their opinions on the design, they landed on the current model.

“Through the survey, we found out people want something bigger, prettier and more durable. Sophie came up with new ideas to make the new system more attractive to people. A few hours on Pinterest later, we had a prototype idea,” said Pattillo.

By April, the duo had built Miniponics 3.0 and installed it in the first-floor lounge area of Science Hall II. A mere five weeks later, the system was flourishing, growing large, healthy plants and continually cycling the nitrogen throughout the system. The system is currently growing Bibb lettuce, cilantro, sugar snap peas and kale. In one cycle, the nitrate levels went from 60 milligrams per liter to 0.75 milligrams per liter, according to Pattillo.

For Rotole, it’s been a great experience for an undergraduate. “Miniponics 3.0 was a great success for me personally. It was a great opportunity to experience the engineering design process. I really enjoyed designing and constructing a product from start to finish and watching it function as intended,” she says.

STEM Outreach
When Pattillo isn’t working on design modifications or measuring water quality, he is involved with outreach efforts with young people. He has always had an affinity for plants and animals, and he enjoys sharing his knowledge with others. He has been a specialist for the World Food Prize Iowa Youth Institute hosted on campus each year by the College of Agriculture and Life Sciences, and has taught Iowa middle school and high school students about aquaponics.

Recently, he partnered with ISU 4-H, working with Jay Staker, ISU Youth and 4-H program manager, to start an aquaponics program at the request of 4-H volunteers and field team members. Staker also reached out to Pattillo to collaborate on an urban agriculture program in Polk County. From there, the program has expanded into hands-on aquaponics workshops for Story County youth.

4-H is looking to expand the program into other counties and make connections with other groups that might be interested, such as local FFA chapters. 4-H continues to provide funding for start-up costs and outreach programs, seeing aquaponics as complementing its gardening and agriculture programs, as well as providing STEM and leadership opportunities.

“This is a learning experience that provides agricultural opportunities that can be implemented in any setting, urban or rural. We’ve also got this growing aquaculture and aquaponics industry in Iowa, so there’s a career component to that as well,” said Staker.

ISU Extension and Outreach and the North Central Regional Aquaculture Center also have been supporting aquaponics through workshops and aquaculture webinars.

Want More Aquaponics?
For those interested in tracking the Miniponics 3.0’s progress or Iowa State’s aquaponics work in general, check out Pattillo’s Twitter handle @ISU_Aquaponics. He frequently tweets photos and updates of Miniponics 3.0, as well as other content related to his work.

Pattillo continues to modify the design, and is in the process of creating a how-to video in partnership with the Agriculture and Natural Resources Extension Communications team in CALS. The goal of the video is to teach the general public how to make an aquaponics system.

Rotole says, “The purpose of our aquaponics project is to provide a living example of sustainable agriculture that all ages of people can implement and experience.”