Print
Bookmark
Related Links
Aquaculture
Fish is an important component of a balanced diet and it is enjoyed all over the world.
It is estimated that fish consumption will rise by nearly 40% to 180 million tonnes by the year 2030. In order to meet this increasing demand more and more fish have to be raised in fish farms.
Aquaculture is currently the fastest growing sector in food production.
Process
Aquaculture is extremely important because it protects the oceans from further over-fishing and produces healthy food with extremely high feed conversion efficiency.
Dissolved oxygen is the most important factor in achieving good results in fish farming. The amount of oxygen needed for optimal fish growth depends on the following:
- species
- size
- feeding rate
- activity level
- water temperature
The rate at which oxygen dissolves in water is greater with pure oxygen; so this plays a significant role in successful aquaculture.
Oxygen can be injected and dissolved into tanks and sea cages by different methods such as:
- Ceramic diffusers
- High velocity venturi /nozzle combination systems
Increased saturation levels offer improved fish welfare and increased growth.
In closed or recycle systems, increased saturation levels are essential for fish survival. Even with highly reliable oxygenated water sources, an emergency backup can reduce risk and prevent the loss of fish stocks.
Benefits
Why should pure oxygen be used in aquaculture if air is available free of charge?
With an aeration system the rate of oxygen transfer into the water is limited by the small difference between the oxygen proportion in the air and the oxygen concentration in the water. Poor aeration capacities and high energy consumption are likely to be the result.
Pure oxygen offers considerable advantages. Air contains only 21% oxygen, so in a pure oxygen environment the oxygen saturation is about five times higher than in air.
The transfer rate of oxygen is proportional to the difference between the saturation concentration (in equilibrium with the gas phase) and the actual concentration in the water. This is why oxygenation systems are much more efficient. For example, in order to maintain an oxygen saturation of 80% in a fresh water basin at 15ºC, a system using pure oxygen at ambient pressure is about 20 times more effective than one which employs aeration.
With pure oxygen, much higher oxygen concentrations can be obtained, so permitting bypass solutions which require less pumping energy.
The risk of super saturation can be safely avoided as no other gas is dissolved.
These considerations clearly demonstrate that the use of pure oxygen is technically as well as economically superior to simple aeration. The advantages more than compensate for the extra cost
Boosting profitability
Pure oxygen has the following economic advantages over simple aeration:
- higher stock densities
- optimum growth rate
- increased production due to reduced cycle times
- feed cost savings due to improved feed utilisation
- minimum fish mortality
- pumping cost savings due to reduced water recirculation
- higher sales price due to average weight gain and higher quality of fish
While oxygenation is well-established in land-based plants, recent research has shown that oxygen control is also of great importance to aquaculture in sea cages
Specialist expertise
Over the years, both BOC and Linde have amassed vast experience in the field of aquaculture and a growing number of customers now rely on our expertise.
With over 500 installations worldwide, The Linde Group is the global market-leader in oxygenation.
In close cooperation with our customers and research institutes, BOC and Linde have developed ground-breaking technologies which contribute to a more effective use of oxygen in aquaculture. This reduces other costs, such as energy, to a minimum.
Each of our oxygenation systems - SOLVOX™, VITOX and REOX - is specially designed to meet the specific conditions of individual fish farms, whether fresh water or salt water plants.
SOLVOX™ is a trademark of The Linde Group.
In our research and development centre for aquaculture located in Ålesund, Norway, we continuously develop and improve products and processes for both fresh water and saltwater plants.
