Recirculating aquaculture systems (RAS) recycle water from the fish tanks so it can be reused. Suited to fish such as salmon, sea bass and sea bream, but also freshwater fish such as trout, this aquaculture model dramatically reduces the amount of water required to produce large volumes of fish.
To maintain water quality in RAS farms, the water must be treated in a number of steps. These include the initial removal of solids, BOD and ammonia, carbon dioxide degassing and oxygenation. In raceways, for instance, the challenge lies in ensuring that the additional oxygen is evenly distributed throughout the entire raceway – and is not just concentrated at the water inlet, as this results in unhealthy fish densities at that point.
Managing variations in oxygen levels
Our SOLVOX® family of oxygenation solutions can support a number of these steps, helping in particular to overcome the problem of fish crowding at the inlet so that fish can thrive throughout the entire raceway. SOLVOX® C and SOLVOX® A dissolvers are designed to maintain a constant oxygen saturation level in all types of RAS tanks. Our SOLVOX® B submerged diffuser hose and SOLVOX® CD ceramic diffuser are ideal for emergency and temporary oxygenation relief. And our SOLVOX® F regulation concept provides precise, real-time control over oxygen flow in response to variations in consumption patterns.
Maintaining water quality in recycled systems
Beyond the precise regulation of oxygen levels, SOLVOX® can help to optimise a number of other parameters. Waste removal can be challenging in round tanks, for instance, where random fish movement causes the waste to become fragmented and widely distributed. SOLVOX® A bundled with SOLVOX® Stream can help here by concentrating waste in the centre of a round tank so it can be removed more effectively. Also available in an all-in-one SOLVOX® OxyStream unit, this energy-saving oxygenation solution contributes to the hydrodynamic optimisation of fish tanks. The microbubbles created by SOLVOX® OxyStream have the added bonus of removing dissolved nitrogen from the water and thus reducing the total gas pressure of the water. This often eliminates the need for external degassing units and maintains fish health, as fish are sensitive to nitrogen supersaturation.
Support and expertise at all stages of the solution lifecycle
In many cases, RAS farmers rely on our application expertise to explore how SOLVOX® can impact system design in general. SOLVOX® has the potential to lower energy costs as it operates at low pressure and to reduce design effort overall by helping to displace dissolved nitrogen. In addition, we can help design downstream gas injection systems for water treatment or ozone disinfection.To suit individual needs, we offer the full range of oxygen supply modes – from cylinder to bulk deliveries, complementing these with professional services tailored to the needs of aquaculture farmers. We support our customers with end-to-end, fully engineered solutions extending from consulting through turnkey SOLVOX® installations to ongoing maintenance and support.