Aquaponics is the integrated culture of fish, plants and beneficial microorganisms grown in a soilless environment. Fish and plants grow in one ecosystem, eliminating the waste they separately produce by turning it into something of use. The waste created by the fish becomes a food source for beneficial microorganisms, which convert into mineral nutrients for the plants. The plants act as a natural filter, cleaning the water for the fish. It’s essentially zero-waste agriculture.
Aquaponics: Our integrated food production systems
Aquaponics research is carried out at ACE year-round using specially designed indoor aquaponics models equipped with state-of-the-art LED lights. The seasonal attached greenhouse is used to demonstrate the technology to public and industry. A variety of vegetables, herbs and water plants are selected based primarily on their market demand. Crops are also selected for their:
Throughout the process, crops are tested for their adaptability to the aquaponics system.
Our aquaponics research is primarily conducted indoors, which requires complete lighting to be supplied by artificial means. Conventional grow light technology, such as HID lamps, has been replaced with more modern options like LEDs. These technologies are all energy efficient and have a long life compared to common HID lamps.
The indoor systems include 12 specially developed recirculating oxygenated aquaponics modules consisting of:
- fish tanks
- sedimentation tanks
- Moving Bed Biofilm Reactors (MBBR)
- Deep Water Culture (DWC) beds
Water recirculation in the system works by hydrostatic pressure. Once the tanks are filled, the water levels remain the same due to a constant pump flow rate and the gravity flow from differing tank heights. The water is pumped from the water collecting tank to the fish tanks and then flows by gravity to the sedimentation tank, MBBR tank, plant troughs and water collecting tank before being pumped back to the fish tanks.
Plants are grown on floating rafts placed on plant trays within the recirculating system. LED lights are suspended 35 centimetres above these floating rafts. Nutrients are provided either from fish effluent or organic liquid fertilizers produced in aerobic bioreactors.
The total volume of each system is 2,000 litres. Concentrated oxygen is exchanged through specially designed oxygen saturators.
Greenhouse aquaponics production begins in March from seeding. Harvesting of aquaponics produce begins in May and continues until the end of October. Although the greenhouse can operate year-round, we typically close it during the winter season to avoid high heating and lighting bills.
Multiple DWC plant beds, located in a nine by 10 metre greenhouse, utilize a side-stream flow from the adjacent tilapia production facility. During the spring, summer and fall, this greenhouse produces a diverse crop mix using the DWC technique. Other systems in the greenhouse include stand-alone media systems and a vertical, flow through Nutrient Film Technique (NFT) system.
Since the water used to grow the greenhouse plants is recirculated back to the fish facility for reuse, pests can be managed through biocontrol – eliminating the need for herbicides or pesticides. As a last resort, organically approved sprays such as soap or living bacteria-based pesticides may be used.
Our focus on developing an intensive water recirculation aquaculture operation naturally evolved into our aquaponics research. This research is multifaceted and has benefitted from the funding provided by NSERC.
Our constant research into new systems and new crops provides unique learning experiences for Lethbridge College students as well as the many visitors who tour the research areas of ACE. Consider booking your tour today.
Conventionally, we’ve used coconut coir, vermiculite and worm casting as seeding media mixes. These mixes allow for good root development without the need for additional fertilization, producing exceptional seedlings to use in a variety of aquaponics systems.
Through an Organic Alberta grant, we conducted trials to produce seeds from aquaponics lettuce crops in an attempt to improve the cultivars for hydroponic production. Seeds were saved from two varieties of lettuce grown in our DWC systems. These seeds were tested for viability and re-grown, creating a sustainable seed production. The excess seeds are now made available to other aquaponics growers in the region.
Cold water aquaponics research
There has been limited research conducted on the use of cold water fish species in aquaponics plant production, primarily due to the sub-optimal water temperatures for producing tropical vegetables. The growth rates of hydroponic vegetables slow down when the culture water is chilled to temperatures ideal for fish species such as:
Producers of these high-value fish are faced with the task of identifying a crop mix that grows well under low temperatures while generating enough income to sustain the production system.
At ACE, we started cold water aquaponics using rainbow trout in 2015. Numerous experiments have been conducted to date that demonstrate the technical feasibility of trout aquaponics in Canada.
New fish species
Barramundi was recently added to the approved fish species list for aquaculture production in Alberta. However, before the fish are released to Alberta producers, they have to go through a quarantine period where the fry are evaluated for the risk of disease introduction. ACE was selected as the only Alberta facility capable of this quarantine.
Barramundi is a high-value fish species that may provide aquaponics producers with a new product and improve the economic potential of existing aquaponics facilities. Ongoing production trials will include identifying crops that are best suited for production in the barramundi water.