The present project has conducted experiments in laboratory and pilot scale with chemical neutralisation of hydrogen peroxide, which, in combination with technological treatment pose a possible solution for onboard well boat treatment of delousing water. The suggested treatment solution has been tested on northern shrimps (Pandalus borealis) to assess ecotoxicological effects. By reducing hydrogen peroxide with the proposed chemical/technological solution, the swimming behaviour among shrimps were barely affected and histopathological changes in gills were mild. If implemented onboard well boats. the suggested solution will efficiently reduce the environmental risk related to hydrogen peroxide and provide the aquaculture industry with a pharmaceutical delousing tool with low environmental impact.