Linde Gases has launched the SOLVOX® DropIn – a highly effective and innovative technology designed to improve the delivery of O2 into fish farming sea cages.

The system is designed to be used in sea cages which experience unhealthy water conditions due to poor oxygen levels or where supplementary oxygen is needed, for example in harvesting tanks. Additionally, the technology is particularly well suited to sea cage oxygenation during sea lice treatment.

Issues surrounding unhealthy water include the presence of sea lice - which can compromise the health of fish. They damage their hosts’ skin through feeding, causing lesions and infections through viruses and bacteria. While sea lice occur naturally in the marine environment, they can represent a particular issue among farmed fish where a more concentrated fish population means infestations can take hold.

If the sea lice concentration rises above a certain threshold, fish farmers need to apply treatments. In sea cages, this treatment can only be applied once the cages have been completely wrapped in tarpaulin in order to maintain the necessary concentration of deloucing chemical within the water. However, as the tarpaulin cuts off new oxygen supply from outside the cage, a supplementary oxygen supply is needed. This has traditionally been done by using a series of perforated hoses which have to be dragged over the cages and then lowered onto the cage floors. A labour-intensive and time-consuming process, it does not always deliver optimum distribution of oxygen.

SOLVOX® DropIn has specifically been designed to deliver ease of operation when supplementing oxygen to sea cages. This innovative, patent-pending oxygenation technology is compact, lightweight and eliminates the need to drag perforated hoses across the cage floor. It comprises an electric pump plus a patented oxygen dissolver and distribution system featuring a venturi nozzle. Using a small crane, SOLVOX® DropIn is easily lowered into the water to the desired depth. It works by sucking water into the lower part of the unit and mixing it with oxygen. The oxygenated water is then distributed throughout the cage through four nozzles situated at the top. The microbubbles created have a low rising velocity so extends the bubble residence time in the water. Combined with the large surface-to-volume ratio, this increases the oxygen dissolution efficiency - even at low pressures. It has also been observed that this much less disruptive method of delivering increased oxygen has resulted in calmer fish behaviour during the delousing treatment.

“Linde has always played a pioneering role in gas technology within the food production and processing market,” commented Stefan Dullstein, Head of Industrial Segment Aquaculture & Water Treatment, Linde. “We are constantly innovating to provide our customers with the most efficient equipment to enable them to do their jobs effectively. SOLVOX® DropIn is truly a break-through in oxygen delivery design. We are delighted to introduce it to our customers.”

SOLVOX® DropIn can be viewed at the AquaNor trade show from 18-21 August in Trondheim, Norway. Visit AGA, Linde’s Norwegian subsidiary, at stand F-530.