Aquaculture

Minimize water consumption

The intensive production of Nordic Salmon and other sea food has increased the need for water purification and residue treatment. It has become an industry to treat the water in the fish tanks to minimize water consumption and to reduce the environmental impact. This again has created a demand for aquaculture sludge handling, becoming the next important step for sustainable fish production. The Scanship process consists of dewatering and drying of the aquaculture sludge. The aquaculture sludge is the residues from Recirculation Aquaculture System (RAS). The RAS technology is used to minimize water consumption and to enhance fish production. Separated solids from the RAS is pumped to the Scanship sludge treatment. This solid content will consist of a sludge with low concentrations of about 0,5% DM (Dried Material). The sludge is filtered through belt filters to increase the concentration to 5-10% DM. The pore size of the filter cloth ensures the correct effluent return to the RAS. The sludge from the belt filters is dewatered with decanter centrifuges, increasing the dryness to 25-30% DM. Addition of a flocculant ensures both the high dryness and purified reject waters from the process. The sludge from the decanters is processed in a Scanship batch dryer system, where the dry solids is increased to 85% DM before being bagged. Further handling of the dried bio residuals will vary from fish plant to fish plant. It may be used for agricultural soil enhancement, heat and energy recovery, or as a valuable feedstock in other industrial applications. The volume reduction of the aquaculture sludge through the Scanship process is very efficient, reducing the residues down to about 0.5% of its original volume.