Circular ecosystems with fish and sea asparagus

Alpha Aqua A/S and Aalborg University Esbjerg are at the forefront of a major EU research project where 17 European partners from seven countries develop innovative models for sustainable production of fish and plants in a circular ecosystem. The large EU project has been named Aqua-Combine.

Alpha Aqua A/S is set to launch a fully equipped turbot and sea asparagus farm with Aalborg University Esbjerg as a partner who are to build a pilot plant to extract healthy substances from sea asparagus.

Multifunctional beach plant

Sea asparagus is a gastronomic specialty with some wastage. The tips of the plants are sold to restaurants and supermarkets, while the woody remains – approx. 60 per cent. of the plant – is often not used.

However, they contain healthy antioxidants and anti-inflammatory substances that can be extracted for cosmetics or dairy products. The plant residues can also be used for biofuel or especially nourishing fish feed, while fish residues and return water from the fish tanks with recycling technology can nourish the plants.

“We know that when sea asparagus is combined with salt water from fish production, it grows insanely fast and much better than we can do with artificial fertilizers. We are now working together to boost that effect. And this is something we could never have gotten into if we were not involved in such a project”, says Johan Højgaard.

At the port of Esbjerg, Alpha Aqua’s ambition is to use an old ice factory’s fully automatic high storage. The sea asparagus should grow in up to 7,500 pallet-size growth boxes, which can be called down with elevators when the plants are to be harvested.

From different types of fish tanks on the floor, the return water is sent up to 25 meters in height to flow down into the boxes. CO2 from the fish farm vent is sent back into the boxes to nourish the plants.

Works anywhere

Alpha Aqua is one of three European companies to produce sea asparagus. Each company has a unique approach, but Alpha Aqua’s system is the most innovative of the project. The modular growth boxes can be freely placed on, for example, fields where a high salt content has destroyed agricultural land or on coasts. The system can even be used to create floating farms at sea.

“We need to demonstrate a concept that is flexible, cheaper and that can in principle be used anywhere – and here the Alpha Aqua system also has huge strength. That is a 100% closed system, so you can drop it anywhere in Europe. It can run individually and independently of the surrounding environment to avoid pollution”, says Mette Hedegaard Thomsen, project manager and associate professor at Aalborg University Esbjerg.

Unique growth opportunities

“The project extends across Europe and brings together companies and organisations whose competences complement each other. Each of them contributes to utilising the various residues from Alpha Aqua’s aquaculture system to produce a number of valuable products”, says Pernille Dagø of the Southern Danish EU Office in Brussels. She has helped the project on its way with guidance and contact with European partners. “It shows the unique growth opportunities that arise when companies jump into international partnerships, especially with a circular economy mindset in mind”, she says.