Interview with Jim Rugarber on April 7th, 2020
On April 7th we had the privilege of speaking with Jim Rugarber about his growing knowledge of aquaponics. Jim is a high school teacher in Pennsylvania who has spearheaded an engineering course teaching students about sustainable energy. The course allows students to take an active role in designing, constructing and maintaining their own aquaponic system. Jim has constructed the course to push students in their engineering mindset. They have to work within their teams to problem solve and make a system that will function in their school's old gym. Coming from an engineering college, we can certainly say that Jim is setting his students up for success. These skills will help the students tremendously throughout their STEM educations and are skills that we have to use everyday as engineering students at the college level.
How do the teams work?
Within Jim’s course there are two periods. Each period is an aquaponics team that designs their own system. Within each team the students break up into four groups: build group, filter group, fish groups and grow groups. The students get to pick their group based upon what they find most interesting. Then within each group there is a group leader which Jim calls the ‘Foreman’. The foreman is responsible for communicating the ideas of their group to the larger aquaponics team, as well as to Jim. Jim could be denoted as the ‘boss’ of a project, or the overseer. The students will bring ideas and challenges to him and he will help them through it. However, his goal is to have the students work together within their teams. This pushes the students to work together to design and problem solve with each other throughout the year.
With each new academic year brings a new set of students and with that, a new set of systems. Jim wants his students to experience the entire engineering process and as any engineer will tell you, that includes the entire design process. From design to prototype to revisions and ultimately a final design. At the beginning of the year the students build their system and at the end, they take it apart. This is very conducive to the life cycle of their fish within the systems. If they are able to get their Tilapia into the system by October, then by June they have mature enough fish to take out of the system. This allows for the students to see the full life cycle of an aquaponic system from concept to harvest.
The Systems
Now let's see what types of systems his students decided to build! Both systems are housed within a greenhouse they built in an old gym of the school. Jim described how both groups share a single 300 gallon fish tank, radial flow filter and sump pump, then the water is pumped in two different directions. Each leading to one of the groups. Both groups then have the water lead to a media bed which then leads to a nutrient film technique (NFT) system. One of the groups has their system end here and then flow back to the fish tank. The other groups decided to make their system a little more complex. They added a deep water culture at the end of the NFT system. Then following the NFT, the water feeds back into the fish tank. Within these systems the students are currently growing lettuce, broccoli, basil, celery, peas and cilantro.
The left and center images show the green house with both systems inside. The right image shows some of the plants that are growing within one of the systems.
The left image depicts a front view of the system and the right image shows the schematics of the fish tank, radial flow filter and sump pump.
"Nutrient film technique (NFT) is a hydroponic technique where in a very shallow stream of water containing all the dissolved nutrients required for plant growth is re-circulated past the bare roots of plants in a watertight gully, also known as channels."
Both images show the two NFT systems within the two aquaponic designs.
Materials
Temperature control: Built a greenhouse around the systems. Made a frame out of different materials and covered it in plastic.
Heat: There are heaters within the greenhouse and there is also a heater directly in the fish tank to keep the water warm enough for the Tilapia.
Light for the plants: Grow lights.
NFT system: Made of 4 metal rain gutters that are each 10 feet long. On top of the gutters they used Lexan, which is a thin plastic. They then cut holes in the Lexan for the grow cups.
Sump pump: Made with a chop and flip system using a white IBC tote.
Radial filter: Used a 55 gallon garbage can with a thin piece of plastic bent into a circle. The plastic is held in place by a couple of rivets and then there is a piece of tubing that runs through it.
Media beds: One is made from two by six pieces of wood and three quarter inch plywood. It is very heavy. The other is made of an IBC brown container that he cut in half.
Deep water culture: made from the other half of the IBC brown container that was cut
What do they do with the fish and plants?
When it’s time to harvest, Jim’s class gets to have some fun parties! Last year Jim brought his grill to school and they filleted the fresh Tilapia and had a fish fry. This year they had an abundance of lettuce so they had a salad party. The students coordinated to bring in different toppings and dressings and they had a class period of creating different salads.
This is an image of the Tilapia once they were full grown and on their way to the fish fry.
Challenges/ Advice From Jim
PVC fittings are a great material to use, but their price does add up quickly. Make sure to factor this into any type of budgeting that you do for your system.
Build and play around with your system design, especially if you are using a bell siphon system. They can be tricky in terms of the water flow and coordination levels with your media bed set up. You learn the most by making your design and working through the challenges that your pumps will most certainly bring.
Pay attention to the levels of water and amount of ammonia in it.
If you are building a system indoors, you may have trouble with the types of crops you decide to grow. They previously tried foods such as tomatoes and pepper, but they only got a few flowers because they weren’t outside to get pollinated.
We would like to thank Jim Rugarber for taking the time to speak with us! It was amazing to hear about the incredible systems that his students are able to put together. We wish him the best of luck with his future aquaponic endeavors. The information he shared with us will not only help us with our aquaponic system design, but also in the construction of our educational material! Thank you Jim!
We hope you all had fun seeing what Jim is doing in Pennsylvania! If you have a system or tip you would like to share with us feel free to send us an email through the "Let Us Know What You Think" form below this post!
Sources
Nutrient Film Technique System definition: https://en.wikipedia.org/wiki/Nutrient_film_technique
All photos came from Jim Rugarber
Content information came from Jim Rugarber