Mitigating off-flavour compounds geosmin and 2-methylisoborneol by applying capacitive deionization and nanotechnology in RAS (CDI-NANO-RAS)

Recirculating Aquaculture System (RAS) technology offers opportunities to reduce the environmental footprint of traditional aquaculture production systems, including problems with sea lice, microbial pathogenic diseases as well as algal blooms, which result in the death of millions of fish per year.

The biggest constraints to further expansion of RAS systems is the associated risk of off‐flavours and odours accumulating in the fish flesh, which are mainly caused by the bacteria-produced geosmin and 2-methylisoborneol, and will dramatically reduce the quality and value of fish products.

Conventional antimicrobial technologies cannot be adopted because RAS also relies on a biofilter with thriving microorganisms.

For the first time, we propose to manage off-flavors by controlling bacterial growth in biofilms and in the water column, while leaving bacteria in the biofilter undisturbed.

The aim is to tackle this challenge by implementing two novel and location-specific antimicrobial technologies, capacitive deionization (CDI) and photocatalytic nanostructure based composite coatings or films, for controlling the microbial load and anti-biofouling in RAS and purge tanks, so that do not leave behind antimicrobial to circulate in the system.

The impact of the two new technologies will be addressed by monitoring key “health” indicators of the RAS, the geosmin production, and the changes that these technologies cause in the resident microbial communities.