REALM Brings Greenhouse Farmers and Algae Producers Together

REALM is a European agricultural research project funded by Horizon Europe, looking to improve techniques for dealing with the climate crisis. Global warming, combined with more frequent extreme weather events, suggest that we re-design agricultural and industrial processes which require high amounts of fresh water. Freshwater supplies are declining worldwide; greenhouses and microalgae production, like many other industries, need to reduce their freshwater demand.

Run-off from greenhouses or improperly treated drain water can cause environmental problems. Nitrogen, phosphorus, and other nutrients added to the irrigation water for fast and healthy plant growth can be washed into rivers and lakes. Due to the high nutrient load in these waters, wild plants and deleterious algae grow excessively and quickly degrade the water quality.

New research shows that microalgae can help combat both problems. Instead of using pure fresh water, microalgae can be cultivated in drain water from greenhouses. As the microalgae grow in the drain water, they remove the nitrogen and phosphorus therein. This prevents the accumulation of these nutrients in the environment, keeping clean freshwater bodies clean.

European microalgae researchers, agricultural producers and technology experts connected the dots and initiated the new research project: REALM (Reusing Effluents from Agriculture to unLock the potential of Microalgae). They plan to join greenhouse farmers with microalgae producers in the most economical way. Currently, companies and universities from Belgium, Finland, Germany, Netherlands, Portugal, Spain, and the UK are participating in the project.

Mariana Carneiro (left), João Navalho and Alexandre Rodrigues from Necton, the company that coordinates the REALM project.

Turning Costs into Revenue

“Recycling irrigation water is a cost. With microalgae, this cost can be turned into revenue,” said microalgae specialist Alexandre Rodrigues from Necton, the company that coordinates REALM. “By having microalgae production facilities close to the greenhouses, microalgae producers will be getting free water and nutrients. They will clean that water and transform it into valuable microalgae, which can be used in innovative products to grow plants faster or to grow fish healthier.”

“The production of microalgae can be very sustainable,” says biotechnologist Mariana Carneiro, also from Necton. “In REALM, we will use the drain water as a source of both water and nutrients. We will use the sun as the main energy source, and we will try to validate a direct air capture system that concentrates CO₂ from the air. Microalgae can be a natural and sustainable source of interesting compounds, which is why we should keep exploring its potential and improving its production.”

Last month, the interdisciplinary team started working to make the REALM concept a reality. Within the next four years, they want to establish automatic, low-cost open pond systems that grow microalgae next to greenhouses. Sensors in the system will monitor the growth of the microalgae and the removal of nitrogen. The researchers anticipate decreasing the nitrate content in the drain water to below the EU limit, which is currently set at 50 milligrams per liter.

At the same time, the system is intending to reduce the costs of growing microalgae by up to fifty percent. According to the team, a production price of less than 10 Euros per kilogram (dry weight) is plausible. Reduced production costs can help microalgae producers reach more sectors and lower prices in the markets.

REALM partners would like to see greenhouse farmers and microalgae producers adopt the REALM concept and help each other overcome some of the biggest challenges they face today.