AlgaCycle Project Applies Circular Bioeconomy to Microalgae

 Seagriculture EU 2024
AlgaCycle tubular photobioreactor Necton

Within the AlgaCycle project, a tubular photobioreactor of 19m3 was used for drainage water treatment and production of microalgal biomass.

The AlgaCycle project, led by the Portuguese company Necton S.A., one of the oldest microalgae producers in Europe, was envisioned to develop sustainable products for aquaculture and agriculture, from a resource considered as waste — the drainage water — in a concept of circular economy.

But first, a little background. Portugal, as well as other European countries, has been highly affected by severe drought over the years, especially during summer, with the southern part of the country the most affected due to high temperatures and low annual precipitation. Drought conditions have a significant impact on agriculture production, with a decrease in productivity and product quality, especially when 60% of the total water usage is destined for agricultural practices.

Hydroponics presents advantages

To fight these severe environmental conditions, new strategies have been put in place by the farmers, including the production of food using soilless plant production systems (hydroponics), which presents advantages such as higher nutritional control, higher productivity, and food quality, and most importantly a great reduction in water usage, since highly precise irrigation methods are used.

Although these systems present a lower water consumption due to a better efficiency of the irrigation water, the excess drainage water (water with nutrients not assimilated by the plants) still represents an interesting amount that can be utilized, since it can represent 30% of the global water used during food production. Additionally, the drainage water may still have a concentration of nutrients, mainly nitrates and phosphates, which sometimes are higher than those admissible by the Portuguese legal limit for discharge. Therefore, action is needed on the part of the farmers, since drainage water with high amount of nutrients cannot be discharged without treatment, as it can contaminate soils, aquifers, and other water bodies.

AlgaCycle was funded by EEA Norway Grants and its main objective is to use the drainage water from hydroponic greenhouses as a culture medium for microalgae production, since this water has all the necessary nutrients for their growth. This way, value is created, and a problem is solved at the same time. Microalgae are produced in a cheaper and more sustainable way, saving water and nutrients, and excess nutrients are removed from the drainage water.

It started with growth optimization

The project started with microalgae growth optimization in drainage water, supplied by the company Hubel Verde, at lab-scale at University of Algarve (Portugal). Then, microalgae growth and water treatment were done at pilot- and industrial-scale, at Necton S.A. facilities (Portugal), the leader of the project.

The biomass from this process, obtained in a more sustainable way, has already been tested in aquaculture products, as a substitute for non-sustainable ingredients in commercial feed, like soybean or fish meal, and will be tested as an agriculture product, as a biofertilizer or biostimulant, replacing industrially synthesized fertilizers.

To reach these results, the contribution of the other project partners is essential: Hubel Verde, Portuguese company dedicated to agriculture; Hubel Engenharia e Sustentabilidade, a technological engineering and automation company also from Portugal; Nord University from Norway, with know-how on aquaculture; and NIBIO, with know-how about phytohormones and plant stimulants, also from Norway.

AlgaCycle is highly aligned with several European Union strategies, such as the Circular Bioeconomy Strategy, which aims to provide environmentally sustainable production processes that satisfy food-related needs, as well as reduce the current demand for fertilizers and pesticides of chemical origin by 2030.

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