Aquaponics - Definition

Aquaponics is a system of food production that merges the conventional aquaculture (which is the raising of aquatic animals like snails, fish, crabs or shrimp in ponds), with the hydroponics (the culture of plants in soil less conditions) in a symbiotic environment.

In traditional aquaculture, aquatic effluents from the aquatic animals accumulate in the water, raising the toxicity for the aquatic organisms. This effluent rich water is redirected to the hydroponic system, where the toxic components generated in aquaculture are transformed by nitrification bacteria, and then filtrated by the plants as nutrients. After this, the purified water is recirculated again to the animals.

Components

Aquaponics consists of two main components, the aquaculture section to raise aquatic animals, and the hydroponic section to grow plants.

Aquatic effluents, resulting from uneaten food or raising animals like fish, accumulate in the water because of the closed recirculating nature of most of the aquaculture systems. This effluent-rich water becomes toxic for aquatic animals in high concentrations, but these effluents contain essential nutrients for the normal grow of plants.

Even as the aquaponics system is mainly build with this two components, usually it is grouped in different subsystems responsible for the removal of solid waste, for adding bases to neutralize acids, or to maintain water oxygen levels. Most common components include:

• Rearing tank: the tanks for raising and feeding the fish.
• Settling basin: a unit for catching uneaten food and detached bio films, and for settling out fine particulates.
• Bio filter: a place where the nitrification bacteria can grow and convert ammonia into nitrates, which are usable by the plants.
• Hydroponics subsystem: the portion of the system where plants are grown by absorbing excess nutrients from the water.
• Sump: the lowest point in the system where the water flows to and from which it is pumped back to the rearing tanks.

Depending at the cost and complexity level of the aquaponics system, the hydroponics system, the settling basin and the bio filter can be merged into one single unit or subsystem, which makes the water flow directly from the aquaculture to the hydroponic section directly.