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Finding value in Norway’s aquaculture waste. Bioretur converts farmed fish sludge into a powder fertiliser as demand for ‘circular economy’ technologies grows.

The intensification of aquaculture has led to more inputs and increased amounts of fish waste, or fish sludge, from production systems. For Norway’s world-leading farmed salmon sector, much of this waste is disposed of at sea, leading to concerns over eutrophication and the wasting of valuable nutrients such as nitrogen and phosphorus.

Thanks to new technology, fish farms are now in a better position than ever to dispose of their waste in innovative ways. One company that’s helping them achieve this is Norwegian firm Bioretur, which provides treatment plants and services to convert fish sludge into fertiliser.

“Our system cleans and dries fish sludge into 90 percent powder,” Bioretur CEO Steinar Wasmuth told the Advocate. “We also offer support services such as operation, transport, handling and processing. We create an approved product without any chemicals or hazardous by-products.”

Bioretur’s system is installed only on land-based farms from smolt and post-smolt production to grow-out facilities. It uses hot air or frictional heat to dry sludge into a powder, which is then transported to a centralised facility and turned into fertiliser by Bioretur’s business partner Terramarine. The transportation and disposal of sludge can leave a huge carbon footprint, but because Bioretur removes the water beforehand, there is very little mass to transport. An electric train is used from locations far north of Norway to reduce carbon footprint further.

Bioretur focuses on delivering equipment that meets cleaning requirements and proves cost-effective and sustainable. Incremental development of technology is done continuously. All systems are remotely controlled from Bioretur’s control room and don’t require any operation or maintenance from fish farm staff.

Read the full article article by Bonnie Waycott here on the Global Aquaculture Advocate website

Photo courtesy: Grieg Seafood

Read more news features and technical articles about the evolution of aquaculture, one of the world’s fastest growing industries, on the Global Aquaculture Advocate website