Algal treatment of biogas digestate and feedstock production

The AlgaeBioGas project introduces algal-bacterial treatment of biogas digestate to the market. By using algae, CO₂ emissions and nutrients contained in the digestate can be recycled, while excess heat can be efficiently utilized. The treated digestate is of such quality that it can be reused or safely discharged into the environment. The resulting biomass can serve as a biogas substrate, potentially after extracting specific components in a biorefinery. Traditional biological (bacterial) wastewater treatment effectively reduces organic content, but at the cost of significant CO₂ emissions and high energy consumption for aeration. Mineral nutrients flushed with the liquid phase of digestate are lost in bacterial sludge, which is often deposited, incinerated, or discharged into the environment. Algae hold great potential due to their high growth rate, ease of production, superior sunlight utilization compared to conventional plants, shorter life cycles, and independence from fertile agricultural land. Biogas plants are rich sources of mineral nutrients, CO₂, and heat. Algal recycling can close material cycles, provide feedstock for high-value bio-based products, and reduce competition between biogas and agricultural crops for food production. The project will establish a demonstration center to showcase the technology under various operating conditions, measure performance characteristics, assess environmental impacts, and provide potential customers with a comprehensive overview of the installation.