Sulphate removal by membrane filtration technology to reduce the risk of fish death due to H2S in recirculating aquaculture systems (Aquasulfat) (39705)

Project Details


Land-based fish-farming is one of the possible strategies for ensuring sustainable growth in the salmon aquaculture industry. When producing post-smolt or salmon up to harvest size in land-based fish-farming, it is often desirable to add seawater.

An important risk in land-based recycling facilities (RAS) with seawater addition is formation of toxic hydrogen sulphide (H2S). Hydrogen sulphide is formed by bacterial degradation of sulphate without oxygen present (anaerobic conditions). The sulphate concentration in seawater is more than 100 times higher than in freshwater, and hence the risk increases as more seawater is added. This has in the recent years led to a several cases of acute fish mortality.

New technology can be crucial for ensuring good water quality and a stable and profitable production of salmonids in land-based facilities, such as removing sulphate from the production water. The aim of the project, owned by the company Enwa Water Technology, is to test and develop a membrane filter technology, which was original developed for use in the oil industry, to reduce sulphate levels in the production water. In the project, the company, together with researchers at the Norwegian Institute for Water Research (NIVA), Norwegian Research Centre (NORCE), University of Bergen, Technical University of Denmark, and Stirling University will investigate the bacterial and chemical mechanisms that convert sulphate in the seawater into hydrogen sulphide and study how this filtration technology affects the water quality in general. It may be necessary to make water chemical adjustments to ensure good fish welfare.

Nanofiltration technology has not previously been tested in modern aquaculture facilities on land and can have a great potential - both for the industry to decrease risk for acute H2S-mortality, and for the company that offers the technology.

Large-scale experiments will be carried out in the fish farm Hardingsmolt AS in Norheimsund, Western Norway.

The project is coordinated by Norwegian Institute for Water Research (NIVA) and funded by The Research Council of Norway (Innovasjonsprosjekt i næringslivet - HAVBRUK2).

Research area: Aquaculture
Effective start/end date01/02/2019 → 31/12/2022