SITE: Integrated System of Wastewater Treatment with Macroalgae

The present proposal presents a relevant contribution to the circular economy by promoting the integrated use of marine resources, valuing the effluent of a fish farm as a source of nutrients for production of seaweed species with commercial value. It was designed to answer the problem of excessive nutrient concentration in the effluent of a fish farm, which impacts the water use taxes and the environmental foot print of the fish production unit. The company, AQUACRIA Píscicolas, S.A, presently produces around 200 ton per year of sole in a recirculating aquaculture system (RAS), generating an effluent volume of 60 m3/h that is discharged in sedimentation and infiltration basins. This process is also causing a contamination of the water source leading to its decreased quality and forcing the company to treat the water supplied to the fish tanks. This situation has negative consequences for the company activity, increasing the risks associated with fish pathologies and growth problems, preventing an increase in production.
The challenge is to develop a seaweed cultivation unit, adequate in terms of species and cultivation methods, that uses the nutrient rich fish effluent to produce high quality and high value biomass. The outflow water from the seaweed unit, with low nutrient levels, will present a good quality to be recirculated to the fish tanks. This project will thus develop research on innovative production systems and development of new species for commercial aquaculture, while valuing aquaculture sub products and reducing the environmental footprint.
The present proposal fits into the 2030 Agenda, which sets aims for the contribution and conduct of aquaculture towards food security and nutrition in the use of natural resources so as to ensure sustainable development in economic, social and environmental terms.
According to the open Call N. º 5/2017 of the Blue Fund, the operation contributes to the strategic priority “b) Development of production systems that implement the circular economy of the sea, namely through solutions for the use of by-products of the sea industries, resulting in the reduction of waste with added value and less environmental impact” by “(ii) supporting the demonstration of innovative systems and / or production components designed to extract value from marine resources”; “(iii) promoting aquaculture production of new species, or improving production processes for species already in use, with a focus on food production, feed, parasite control, anti-fouling coatings, or other value-added applications”; “(iv) allowing the use and valorization of by-products from aquaculture, fish processing and fisheries discards”; and “(vi) applying biotechnology to reduce the environmental footprint of economic activities linked to the sea”.