Electron beam (EB) irradiation can disinfect salmon processing sludge to agricultural reuse standards at a levelised treatment cost of USD 45.84/m³ at scale, according to a study by researchers from Chile, Italy, and Austria published in April 2026.
The technique uses ionising radiation to inactivate microorganisms through molecular damage and radiolytic oxidation, requiring no chemical reagents. At a dose of 2 kGy, it achieves at least 99% microbial reduction — a minimum 2-log reduction in indicator bacteria including E. coli and Salmonella.
Chile’s salmon industry generates roughly 1.4 tonnes of sludge per tonne of salmon produced. Against annual output exceeding 1.5 million tonnes, that represents a substantial waste stream. The sludge is rich in organic matter, nitrogen, and phosphorus, but pathogen loads and pharmaceutical residues currently restrict agricultural reuse.
Conventional treatment methods — anaerobic digestion, composting, lime stabilisation, UV disinfection — do not reliably eliminate pathogens or antimicrobial resistance genes, the study states.
Researchers modelled three configurations across approximately 60 processing plants in southern Chile, which generate between 200 and 2,000 m³/day of effluent, according to Sernapesca.
The scaled EB system, processing 10,000 m³/day, reduces total unit costs to USD 0.23/m³ and generates USD 149,850/year in sludge reuse revenue. The payback period reaches 6.8 years. By contrast, a standard-scale EB configuration costs USD 116.69/m³ levelised — making scale the decisive economic variable.
The study recommends pilot-scale validation before industrial deployment. Researchers note that resistant organisms or spores may require higher doses than the 2 kGy baseline used in the model.