1) What is aquaponics?
Aquaponics is the combination of aquaculture (raising fish for food) and hydroponics (raising plants in water rather than soil) in a recirculating system. Fish waste, primarily ammonia, accumulates in the water as a byproduct of feeding the fish in a closed system. The ammonia, which is toxic to the fish, is converted by naturally-occurring bacteria into nitrites, then nitrates. The plants utilize the nitrates for growth, cleaning the water for recirculation to the fish. Aquaponic systems can be small home-sized units or large commercial scale operations.
2) Why aquaponics?
There are several benefits to aquaponics:
- Water usage is minimal with losses coming only from evaporation and consumption by the plants (transpiration);
- Additional chemical nutrients are not needed for plant growth;
- Abundant fish and vegetables can be grown in a small area;
- Food can be produced in areas with limited water availability and poor soil conditions;
- Can produce fish and plants year around. For TMP, these systems provide a way to combat malnutrition and develop sustainable micro-business opportunities in trash dump communities.
3) What are the main components of your aquaponic system?
As you would assume, good quality water, fish and plants are key components. Fish tanks and plant grow beds are the primary containment for the water, nutrients, fish and plants. A water pump and associated plumbing is required to circulate the water. An air blower, piping, and air diffusers will provide oxygen to the fish, plants, and nitrifying bacteria. Biological filtration—consisting of shredded PVC—will provide the necessary habitat to support the bacteria.
4) What fish will you grow?
TMP plans to start each system with Tilapia. Tilapia is a common name for many different species of fish in the Cichlid family. Tilapia is the most common fish used in commercial fish farming operations around the world. These fish are hardy and adapt easily to tank culture; they grow fast, reproduce often, and are available in almost every country. Plus, they taste good and are a good source of protein. Internationally, we may find other species that are culturally acceptable and good candidates for high density production.
5) What will you feed the fish?
Tilapia will eat almost anything but naturally feed on a variety of plants. TMP plans to grow duckweed—a small, common, floating plant that reproduces quickly—to feed to our fish. We may supplement the duckweed with other leafy greens from our grow beds or a prepared fish food.
6) How many fish will you grow?
Our goal is to produce one pound of fish for every three gallons of water in the fish tanks. Our current system holds 3,300 gallons of water in the fish tanks so we hope to produce 1,100 pounds of fish every year.
7) What kind of plants can you grow?
Many different types of plants are grown in aquaponic systems including herbs, leafy greens, beans, peas, tomatoes, peppers, squash, fruit and fruit trees, etc. TMP will start with leafy greens and progress to other plants as nutrient levels in our system increase. For overseas systems, we will research local plants and cultural preferences to determine the most appropriate plants to improve nutrition.
8) How will you grow your plants?
Plant seeds will be sprouted in net pots containing coconut fiber. Once large enough, the net pots will be transferred to Styrofoam rafts floating in the grow beds. Each of the grow beds have a length of 23 feet and a width of 4 feet with water 1.5 feet deep. The Styrofoam rafts will have holes allowing the seedling roots to dangle into the water and take up the nitrates produced by bacterial conversion of the liquid fish waste.
9) How many vegetables can you produce?
Research indicates that for every pound of fish produced, enough nutrients are generated to grow four to six pounds of vegetation. If we are able to grow 1,100 pounds of fish, we may be able to produce 4,500 to 6,600 pounds of vegetables.
10) What will you do with your fish and produce locally?
First and foremost we donate a portion to Topeka Rescue Mission. In the future, we also plan to market enough of our fish and produce to cover operating expenses (electricity, natural gas, water). We are looking into opportunities for direct sales at farmer’s markets and to restaurants, seafood stores, and individuals.
11) What will you do with your fish and produce internationally?
Our focus will be to improve nutrition in the trash dump communities where we work. The aquaponic system will provide healthy food for our nutrition programs as well help offset operational costs for the program by providing micro business opportunities through fish and vegetable sales.