AquaDegas Case Study

Aquaculture tanks represent a production unit, where a managed volume of fish can spawn and grow while being control-fed in optimal water quality. The management of fish stock nutrient uptake is relatively straight forward, as fish food can be carefully formulated and added in controlled amounts. However, optimising the quality of the water in which the fish swim is a much greater challenge. This is especially true with dissolved gases, which can quickly become oversaturated and lead to fish stress and death. In spite of the fact that the water quality is vitally important for optimal growth and animal welfare, there are surprisingly few devices available for removing oversaturated gases (such as carbon dioxide, nitrogen and argon) from the tanks.

AquaDegas, a research project co-funded by the European Commission’s Sixth Framework Programme, is addressing this problem by developing a cost-effective, efficient and compact method to de-gas fish tanks. Using novel ejector and sensor technology developed by the project team, dissolved gas concentrations can be monitored and accurately adjusted using sensitive control equipment.

The method works by using the specially-developed ejectors to produce microbubbles in the water of the fish tank. The ejectors:

• have a simple, compact design
• need no pressurised air intake
• require no power
• can operate at very high flow rates
• require virtually no maintenance
• can be easily retrofitted into existing fish farms.

By removing harmful gases and accurately controlling oxygen concentration in the water, the AquaDegas system will allow fish farmers to increase production by allowing more fish to be farmed in the same tanks, increasing fish growth rates and reducing fish stress and mortality. Accurate control of the water conditions will also allow fish farmers to diversify into the production of species that cannot by farmed using current technology. After final optimisation of the system, the AquaDegas project will lead to large benefits for the aquaculture sector, including increasing the competitiveness of European fish farms, boosting annual production by at least 5% and increasing European sales of farmed fish by over €60M per annum by 2012.