Using aquaponics, Tommy Robinson and Joel Hanson, partners in Aiken Aquaponics, are extending the local growing season year-round for lettuce, herbs and other fruits and vegetables. Aquaponics, which has ancient roots, merges two farming technologies: hydroponics (growing plants in water without soil) and aquaculture (fish farming). Together, the processes produce fresh produce that is all-natural and chemical-free in a system that is environmentally friendly.
"And an added benefit – no weeds," Hanson said, joking.
The sustainable system starts with rainwater, which gutters on the side of the greenhouse catch and store in large tanks.
"I'd say 95 percent of the water we use is rainwater," Robinson said. "Unless it's dry for a long time, we usually don't have to use any City water."
A sump pump pumps the rainwater about 8 feet up and into the greenhouse to a large fish tank filled with tilapia. From that tank, the water flows into another that filters out the solid waste from the fish, leaving ammonia and nitrites.
In the next tank, bacteria convert the ammonia and nitrites in the water into nitrates, which is plant food.
That nutrient-rich water then flows into the beds to feed the plants, which in turn, remove the nitrates before the water loops back to complete the circle, and the process starts again.
Gravity drives the system.
"Gravity works really well," Hanson said. "It's just the one pump that runs the whole system, and it's not a very big pump. We try to keep the loop as closed as we possibly can. It's definitely sustainable."