The Theory Behind How Aquaponics Works
How does aquaponics work? Here is a short and simple Aquaponics definition- A combination of Aquaculture (the farming and raising of fish) combined with Hydroponics (plants growing in a soil-less system).
In Aquaponics, the fish waste along with a significant volume of water it resides in , does not need to be removed daily as it does in an Aquaculture system. Costly plant food does not need to be added as it would with a hydroponic system. Also there is no need to flush out the grow beds periodically to replace it with water that is fresh and clean.
Aquaponics thus becomes a system of growing fish, produce, and other plants types in a sustainable closed-loop system.
The Aquaponics System Cycle
- First the fish in the aquaponics tank are fed with fish food supplied by the grower.
- Fish secrete waste and ammonia that can be detrimental to the fish in sufficient quantities.
- The fish breath in oxygen but exhale carbon. The water is contaminated with fish waste and carbon. The fish tank water is cycled into the plant grow bed media.
- The grow bed media is a perfect environment to billions of bacterial microbes that convert the ammonia initially to Nitrite, and then to Nitrate.
- The plant roots absorb the nutrient-rich Nitrate and the carbon helping to clean the water while elevating the health of the plant.
- The purified water is poured back into the fish tank while oxygenating it at the same time.
Two Basic Types of Aquaponics Grow Beds
To understand the answer to “how does aquaponcs work”, it’s best to learn the differences between a simple and complex Aquaponics system.
In simple Aquaponics systems, grow beds harboring the bacterial microbes become a natural bio-filter helping to purify the water. The bacteria can process the volume of fish ammonia secreted in the urine. Additional fish excretions of fecal matter, plant decay, and left over fish food enter the system as solid waste. The bacteria will break these elements down as well in a small simple system.
However, in more complex systems with more fish and plant growth, a separate filtration device is necessary to help filter out the solid waste and purify the water.The filter device is placed between the pipe that is delivering water from the fish, and the pipe that delivers the water to the grow bed. These larger systems will also require a pump to cycle the water through the pipes.
Aquaponics systems have expanded to a wide variety of configurations in the last 30 years. They all still run on the same common components of a soil free grow bed for the plants, a tank of water where the fish live, and microbes (bacteria) in the water. Other variables added to make the system more efficient depending on its overall size:
- Plumbing to circulate the water (pipes and/or tubes)
- Separate filtration devices
- Siphon Bell to drain the water from the grow bed when it reaches a predetermined lever
- Manual and automated valves
More History of Aquaponics
Ancient agricultural cultures played a role in developing ways to grow food without planting them in soil. The Mayans and Aztecs used rafts 1000 years ago carrying plants that functioned much like hydroponic and aquaponics system grow beds of today . They floated on lakes with roots dangling in the water below. Essentially these were much like modern day hydroponics that grow plants in a soil-less environment.
There is also evidence of similar soil-less practices in far eastern countries of China, Indonesia, and Thailand. In these instances they actually used fish in a symbiotic relationship with the plants.
Fast forwarding to the late 20th century, fish farmers were continuously looking for better ways to raise fish. The aquaculture industry needed systems that would minimize the dependence on resources like soil and water.
Typically fish farming utilized large ponds and pens contained in netting off the coastlines known as RAS, Recirculating Aquaculture Systems. Researchers began developing systems that used plants as a filter in fish farm systems. Eventually experiments led to actual closed-loop aquaponic systems in the mid 1980’s.
In the early 90’s Tom and Paula Speraneo, a couple of farmers in Missouri, used Ebb and Flow grow beds to grow vegetables and herbs. Nutrient-rich water was pumped into the grow beds from a tank full of Tilapia fish. This system began to be duplicated, and has grown to backyard systems as well as commercial factory’s of Aquaponics systems around the world.