Concurrently with the increase population food demand, European aquaculture sector is fast growing, accounting with 15,000 companies in 2018 that produced 3 million tonnes of aquaculture products and employed directly 69,000 people. Unfortunately, the aquaculture activity is linked with the generation of large volumes of animal by-products (ABPs) not intended for human consumption that need to be managed according to Regulation (EC) No 1069/2009. Dead animals due to disease or other causes (7-10% of total production); animals unfit for consumption for hygienic-sanitary reasons (~0.07%); rests of animals obtained during the fish transformation process (e.g. viscera, head, skeleton and fins, that can comprise up to 70% of processed fish); and sludge (consisting mainly of fish faeces and unconsumed feed) are included in the category of ABPs.
Although ABPs management alternatives exist, they are mainly focused on minimising the potential risk to human and animal health. In this sense, dead animals are frequently managed by means of incineration or anaerobic digestion, whereas viscera and heads are processed to produce animal feed and fish oil. However, harnessing their content in valuable elements such as nutrients or proteins to produce high added-value products such as bio-based fertilisers (BBF) and biostimulants, is considered an interesting opportunity to boost the alignment of the aquaculture sector with the current European circular bioeconomy strategy. Bearing this objective in mind, SEA2LAND promotes the valorisation of aquaculture industry by-products by implementing innovative technologies to recover products with agronomic value.
To cover the most significant regions with aquaculture production in Europe, 4 demonstration pilots will be implemented in 3 representative areas (North Sea Area, Atlantic Area and Mediterranean Area). The technological approach proposed for the valorisation of aquaculture industry by-products is based on the application of:
- Bokashi fermenting technology in the North Sea pilot
- Thermo-Mechano-Chemical fractionation by Twin-Screw extrusion (TMC) in the Atlantic pilot
- Biodrying and Freeze Concentration among other intermediate technologies in the Mediterranean pilot, where both brackish and freshwater aquaculture sludge will be valorised
Considering all aquaculture demonstration pilots to be assessed in SEA2LAND, 7 bio-based fertilisers are expected to be obtained, either mineral (e.g. ammonium salts, phosphoric acid) or organic (e.g. pelleted bokashi product, TMC fermented fractions, biodried organic amendment). Besides, fertilising products obtained could be used directly in agriculture or as primary ingredients for the formulation of crop-adapted tailor-made fertilisers.