To shorten production time at sea, Eidesvik Settefisk builds new plant for post-smolt. The plant will be based on recirculation of water and take the fish from 100 grammes to 500 grammes before launching to sea pens.

Thomas Haugehåtveit of Sterner, Lars Magne Eidesvik of Eidesvik Settefisk, Alf Gunnar Øverbø of Sterner og Terje Gram of Multiconsult will work together to build a new post-smolt plant.

Eidesvik Group produces yearly 4500 tonnes  of salmon from their own smolt plant and at four sea sites. To shorten the period at sea, the Group now builds a post-smolt plant of NOK 45 mill. The plant comes with integrated recirculation of water.

“Today the smolt is 100 grammes when launched at sea. The growth period before harvest is between 18 and 20 months. If we let it grow 3-5 months in the post-smolt unit it will be presumably 500 grammes when put in sea cages. And so the period at sea will be less than one year,” explains Lars Magne Eidesvik of Eidesvik Settefisk, part of Eidesvik Group.

In addition to shorter production time, a large post-smolt will be more robust and less prone to diseases, which leads to lower mortality and higher product quality. The existing smolt plant will supply the fish going to the post-smolt plant, which will have a capacity of 600 000 fisk yearly, in three cycles.

The water temperature in the post-smolt plant will hold between 12 an 16 degrees C, which will ensure good growth. There will be two large fish tanks, five meter deep and 15 meter in diameter. We water treatment will be in a separate building and consist of screen filter and biofilter. To keep the CO2-content down there will be a two step CO2 removal, which also ensures a low ammonium level. The plant will run on brackish water. The plant will neighbour the existing smolt plant.

The thickening of waste will commence in the center of the fish tank, due to a new hydraulic design and a special outlet solution. The central outlet will have several functions: fish exit, sludge exit and dead fish exit.

“The outlet is supported by a higher turnover of water, and is the key to effective capture of concentrated sludge. We have conducted pilot trials of this part in cooperation with the client,” explains Steinar Skybakmoen of Sterner, who will build the tanks and the recirculation system.

The post-smolt plant is number five in a row delivered by Sterner. The buildings will be constructed by local entrepreneurs, under the leadership of Multiconsult, who will design the building.

“The plant will ensure a good total economy through a high feed conversion ratio. It will also ensure a good water quality for the fish and clean tank environment,”  according to mr. Steinar Skybakmoen of Sterner.