Norwegian salmon farmer Nova Sea has increased the oxygen content in its waiting cages outside its packing facility in Lovund, North Norway, with 20 percent after implementing newly developed pump technology.
“20 percent increase in oxygen has a positive impact on fish welfare and the quality of the fish we produce. It also means that we can utilise the current waiting cage capacity better, which in turn leads to improved wellboat logistics and more stable harvesting capacity,” says Terje Sølna, factory manager at Nova Sea at Lovund.
The reason for the technology investment is that the six waiting cages outside the company’s packing facility at Lovund are located at the inside of pier that limits the inflow of oxygen-rich, new seawater to Nova Sea’s cages. When a wellboat then fills the waiting cages with up to 100,000 salmon at an average weight of 5.2 kg, the oxygen level in the cages decreases for natural reasons.
Nova Sea therefore contacted the liquid and pump specialists in Norwegian company PG Flow Solutions that has developed a high capacity seawater pump called PG-Subflow.
By installing the PG-Subflow pump system outside the pier, pulling a guide pipe through the pier, and then directing the flow towards the waiting cages, 20,000 cubic metres of fresh seawater per hour is pumped towards the waiting cages on the inside of the pier.
“We measure the water quality continuously and have measured a 20 percent oxygen increase in the waiting cages after just 30 minutes of pumping with PG-Subflow. That is impressive,” says Terje Solna, but also in line with the expectations to the solution.
PG Flow Solutions’ pump technology centre has developed, assembled, delivered and installed the PG-Subflow, which is a high capacity propeller pump with two counter-rotating propellers. Each propeller is driven by a separate electric motor, and by frequency converters each RPM can be optimized to the duty. All equipment is electric and suitable for submerged operations in seawater.
“These are high capacity pumps capable of pumping 20,000 cubic metres of seawater per hour despite the relatively modest 21.5 kilowatt effect per pump, which contributes towards keeping operational costs as low as possible, says Øyvind Berg, vice president sales and marketing at PG Flow Solutions.
In addition to the pump system, PG Flow Solutions has also delivered the flow pipes that extend from outside pier and through the pier to the discharge point 8-10 metres inside the wall of the pier. PG Flow Solutions carried out the installation of the pumps, while Nova Sea was responsible for lifting and foundation work.
Nova Sea is the first company to start using PG-Subflow.
“The pump system has been running continuously since mid-July, with very good results. The six waiting cages receive a steady and oxygen rich flow of fresh seawater, but without thrusting the cage nets so that they apply pressure on the fish. We are very pleased with the collaboration with Nova Sea and are already experiencing increased interest in PG-Subflow from other fish farming players, says Oyvind Berg.
Nova Sea’s packing facility at Lovund has a daily capacity of 320 tonnes live salmon and 30 tonnes of filet. The facility employs approximately 125 people.
PG Flow Solutions provides proprietary solutions, systems and products for companies within aquaculture, maritime industries, energy sectors and land-based process industries. The company’s headquarter and manufacturing facility is located in Sande, Vestfold, Norway.