Sustainable aquaculture has become the solution to the overfishing, mismanagement of crucial feeding grounds and unsustainable farming methods that are threatening fish stocks and the long-term supply of fish to market. However, farmer have struggled with how these farmed fish will be sustainably fed? Polychaetes are nutritionally rich, high quality aquatic worms increasingly used in shrimp and finfish feed. FishfromGB, in collaboration with the University of Edinburgh and with funding from the Scottish Funding Council, have developed a prototype “polychaete biofilter” under laboratory conditions. This high-density biofilter allows the worms to successfully feed upon aquacultural wastewater. Using Innovate funding we would deploy this biofilter as part of the filtration system used in a small Recirculating Aquaculture System (RAS), determine it's scalability, and then install a full-scale model at our aquaculture facility in West Lothian. Demonstrating a sustainable engineering solution for the inexpensive bioremediation of different types of aquaculture effluents, this biofilter also translates into a circular economy system; the bioremediated wastewater can be reused (especially in recirculating aquaculture systems) and the ragworm biomass, which has significant market value, can be then used as a premium component in aqua feeds. If the full-scale system proves to be viable, the uses in wider Scottish aquaculture, in food production and longer-term even in municipal water treatment systems are many, with the system easily exported to the wider world.