Aquaponics is the symbiotic cultivation of plants and fish in a re-circulating system. Growing Power, a community-based urban food center in Milwaukee, WI uses Tilapia and Yellow Perch to fertilize a variety of crops and herbs using aquaponics.
By using gravity as a transport, water is drained from the fish tank into a gravel bed. Here, beneficial bacteria break down the toxic ammonia in fish waste to nitrite and then to nitrogen, a key nutrient for plant development. Finally, the water flows from the growing beds back into the tank of fish.
Growing fish in cities in a healthy no-waste system like this means more fish can stay in the oceans to repopulate, and our food require less transportation = all good!
This urban farm sells the fish and the plants to local restaurants, and educates people all over the world about this model of urban food sustainability.