Students prepare fish to feed the Pomfret community.
Armed with nets and buckets, students collected the tilapia that have provided waste to grow plants in Pomfret’s passive solar aquaponics greenhouse. They then learned how to fillet the tilapia from Bill Martin, science teacher and founder of The Helios Project. The fish are just one component of the food produced by the greenhouse, which has been feeding members of the Pomfret community since 2018.
The tilapia had been living and contributing to the aquaponic system since December. Their water is continuously cycled to the gravel growing bed and deep water culture tank that contains a variety of vegetable and herb plants — including lettuce, tomato, peppers, and basil. Nitrosomonas bacteria break down the ammonium in the water, a byproduct of the fish, and nitrite is released. Nitrospira and Nitrobacter bacteria convert the nitrite into nitrate, which is absorbed by the plants’ roots along with other inorganic nutrient ions from the fish waste decomposition. The water is then cycled back into the fish tank, free of toxic ammonium and nitrite, and the cyclical symbiotic process continues.
The fish were harvested as the first step in preparing the systems to be shut down and cleaned for the summer. In order to make use of the fish, Martin gathered volunteers to catch and fillet the fish. The filleters carefully prepared and bagged the fish for consumption. They also collected the remaining components of the fish to be used as fertilizer in area gardens. When the greenhouse closes for the season, the plants will be transplanted to the community garden at the Thompson Ecumenical Empowerment Group (TEEG), giving them a second life.
Throughout the academic year, the aquaponic system is monitored by Martin and a team of student interns, who regularly test the pH of the water, harvest the vegetables, and replant seedlings. Produce grown in the greenhouse throughout the year has been donated to the Pomfret Power Packs program and TEEG, as well as to Pomfret’s dining services company, FLIK Independent School Dining.
In their Sustainable Engineering class, students are continually studying, designing, and constructing ways to improve the greenhouse — including how to build the most efficient growing bed. Alex Vincent ’23 is completing his second term in Sustainable Engineering and has been working with Aquaponics classmates to engineer two new vertical growing towers. He is currently building the first tower design that will be tested next fall. “Aquaponics has taught me a lot of things. It is so incredibly interesting,” says Alex. “Most importantly, it has taught me where food comes from and that it is a gift.”