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Converting fish waste to fertiliser

Bioretur provides land-based and closed aquaculture facilities with treatment plants and services to convert fish sludge to fertiliser and other useable resources.

Bioretur treatment plant that converts fish waste into fertiliser

Fish sludge is waste from fish farming, consisting of uneaten fish feed and faeces. The sludge contains important nutrients such as phosphorus and nitrogen, which are essential for all life on earth. However, fish sludge also contains polluting heavy metals such as zinc, nickel and cadmium.

The amount of fish waste is growing as the number of land-based and closed fish farming facilities increases. Much of the waste is disposed of at sea, causing eutrophication, among other problems, and wasting valuable nutrients. In Norway alone, 27 000 metric tons of nitrogen and 9 000 tons of phosphorus are released from fish farms into the sea each year.

Enabling a circular ecosystem for waste from fish farms

Bioretur’s sludge treatment plants clean, dewater and dry fish sludge on site, from 0.1 per cent dry matter to a highly potent powder (90 per cent dry matter).

The company also provides support services consisting of operation of the sludge treatment plants, as well as transport, handling and processing of the waste into usable resources for soil improvement, fertiliser and biogas substrates.

Two men in an office controlling a fish farm waste treatment plant from their computers

The treatment plants are all operated remotely by the process management team in Bergen.

Concrete benefits

Bioretur’s technology and services reduce the waste of valuable nutrients, keeping them in a circular ecosystem. The company’s solutions also reduce the use of chemical fertilisers and minimise marine pollution, while enabling fish farmers to shrink their carbon footprint.

The wastewater released from Bioretur’s installations is clean and the dry sludge collected is utilised in several different ways. These include local biogas production, a natural fertiliser for consumer use called Equus, and an export fertiliser called Minorga. Minorga is distributed in Vietnam where the farmlands contain very little phosphorus.

Market potential

Bioretur is working to become the market leader in sludge treatment for land-based aquaculture. In 2018, 2 000 of the 18 000 fish farming licences awarded in Norway were for facilities on land. Based on customer data, Bioretur estimates that the total lifetime value of waste technology and services in the Norwegian market is approximately NOK 7.5 billion (roughly USD 845 million).

Over the next 10 to 20 years, the Norwegian salmon farming market will grow as more and bigger fish will be farmed in land-based and closed facilities. Internationally, Bioretur expects growth in Canada, Chile, Iceland, New Zealand, Scotland, Russia, the US, and emerging markets.

Worker cutting metal while repairing a Bioretur fish waste treatment plant

The Bioretur service agreement includes everything from maintainence and processing to logistics and handling.

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Storaneset 32, 5260 INDRE ARNA, Norway

+47 477 70 934

At a glance

  • Converts fish sludge to fertiliser and biogas

  • Prevents waste of valuable nutrients

  • Improves water quality and protects marine life



Advancing the Sustainable Development Goals