Introduced gradually over several weeks as the bioreactors reached peak efficiency. The bioreactors convert ammonia, which is toxic to fish, into safer nitrates and also “eats” fine organic solids while removing excess carbon dioxide.
Total water use at SN will eventually decrease by as much as 2/3 from current levels as the remaining flow through systems are converted to or replaced by additional recirculation systems.
Dean Guest, Freshwater Production Manager, said that the first group of 600,000 smolts produced in the new system should be ready for delivery to site in January 2011. “Our expectation is that this system will more than meet our needs,” he said. The key to any successful recirc operation is the ability of the system to maintain stable water chemistry, temperatures,oxygen levels, as feed rates and biomass change.
The system will be able to consistently provide a high standard of water quality throughout the production cycle including times of peak biomass & feeding and the “smolting” process leading up to transfer to sea.
This will help us produce smolts of a consistently high quality from September through May Dean commented. “In our opinion InterAqua Advance has the best technology available”. The company, based in Denmark, has a patent on their recirculation system’s design.
When asked why Marine Harvest has chosen this time to take such significant steps forward,Dean commented that “we needed to end the lake production of smolts in order to decrease potential fish health issues. This investment in our freshwater operations is a key way to increase both smolt size and quality while at the same time reducing environmental concerns”. Two out of the three company’s lake-based hatchery sites are already closed.
The second phase of work is scheduled to begin before the New Year. Four additional tanks and a second bioreactor system will be installed in the same building. Sayward North represents InterAqua Advance’s first system in North America.
By Gina Forsyth