This CASE project explored how waste from renewable energy systems could be transformed into nutritious animal feed. The focus was on using microalgae—tiny plant-like organisms that grow in water—to absorb nutrients from the liquid fraction of the digestate produced by anaerobic digesters (ADs), which are used to create biogas from organic waste. These microalgae were then harvested and used as a feed supplement for livestock.
The microalgae were found to be rich in proteins, vitamins, and healthy fats, making them a promising alternative to traditional feed ingredients. They grow quickly and adapted well to the introduction of liquid digestate as a source of nutrient. This approach not only reduces the environmental impact of digestate management but also created a new, sustainable source of animal nutrition.
The project successfully grew both commercial and wild strains of microalgae in labs in Portaferry, using filtered digestate as a nutrient source. The results identified which strains grew well and produced high levels of beneficial fats, including omega-3s. These findings suggested that microalgae could improve animal health while helping farmers manage waste more effectively.
By developing a system that linked renewable energy production with agriculture, the project supported a circular economy—where waste became a resource. It also strengthened food security by producing feed locally, reducing reliance on imported products. The long-term goal was to scale up production and integrate this system into existing AD facilities across Northern Ireland.