Ranfjord Fiskeprodukter will invest about 20 million NOK in sludge treatment at its smolt plant in Mo i Rana. The environmental investment is made to meet public requirements. It is the sludge from the filtering of the effluent which will be dewatered and dried.
The process solution consists of thickening, dewatering and evaporation. In practice, zero effluent will be obtained from the sludge treatment itself. This is accomplished by purifying the rejection water from the sludge thickening by ultrafiltration.
“Using this sludge treatment, we achieve an overall lowering of our effluents, thus fulfilling public requirements,” says Bjørn Myklebust, managing director at Ranfjord Fiskeprodukter.
At the same time as the investment meets environmental concerns, the sludge will be dried to 90% dry matter.
“It is important for us to get a dried and stable end product. At the same time we use a drying process that is gentle on the nutrients in the sludge, so that it can become the most useful fertilizer product. The aim is to contribute to a circular solution, where waste from fish farming will play a part in agriculture,” says Myklebust.
The drying process utilizes heat pump technology. The process includes several stages where a special Norwegian-developed onion thickener gives a very effective thickening.
The complete sludge treatment plant will be delivered by Sterner and the design basis for the plant is 600 tonnes of fish feed per year.
“We chose the solution after seeing similar plants in operation,” says Myklebust.
The actual sludge treatment accounts for half of the total environmental investments. Sterner has so far delivered 12 sludge treatment plants to the aquaculture industry and besides also works with the production of biogas from corresponding sludge.
Ranfjord Fiskeprodukter AS is located at Mo Industripark, about 2 kilometers from Mo i Rana center. An annual 5.5 million smolt is produced, from 2 plants in the industrial park. The business is owned by fish farmers and has 10 employees.