The pilot plant located in the installations of the BETA Technological Center (University of Vic- Central University of Catalonia) (Catalonia, Spain) will be evaluated to recover nutrients from sludge produced in aquaculture industries operating in the Mediterranean area in order to obtain products with agronomic value. Two types of aquaculture sludge will be valorized through the innovative technological system proposed by BETA TC: i) fish sludge produced in marine aquaculture industries with recirculating systems (RAS) and, ii) sludge produced in the industrial wastewater treatment plant (WWTP) installed in a freshwater aquaculture industry for the treatment of wastewater generated during the fish transformation process. The company AquaBioTech Group located in Malta will be the main supplier of the marine aquaculture sludge in the Mediterranean Area, whereas the company Caviar Pirinea located in the northeast of Spain will be the supplier of the industrial WWTP sludge.

The pilot plant implemented in the Mediterranean Area integrates 5 technological units: membrane technologies (coupling ultrafiltration and reverse osmosis) and freeze concentration for the valorization of the liquid fraction of the sludge and, biodrying, thermal treatment coupled to phosphorous-ash recovery and acid scrubber for the valorization of the solid fraction of the sludge. Once the process is validated operating at optimal conditions in the installations of the BETA TC, the treatment units integrating the pilot plant will be moved to the facilities of the company Caviar Pirinea in order to demonstrate the efficiency of the proposed treatment system in a real environment.

The fertilizing products foreseen to be obtained in the Mediterranean Area are: i) a nutrient-rich concentrate, ii) ammonium salts, iii) a nutrient-rich organic amendment and, iv) phosphoric acid. The products obtained during the valorization of the aquaculture sludge will can be applied directly as bio-based fertilizers (BBF) in field crops and others will be used as precursors for the formulation of tailor-made fertilizers. In order to fulfill the requirements of the fertilizer market, the fertilizer company Fertinagro will collaborate with BETA TC in the production and optimization of the agronomic products produced in the demonstration pilots associated to the Mediterranean Area.