Algae and Biogas Plants: Digestate Remediation and Nutrient Recycling with Algal Systems

Algal treatment of biogas digestate is an innovative approach for biogas plants in search of improved quality of liquid fraction of anaerobic digestate, energetic substrates (feedstock), recycling CO 2 emissions, effective use of excess heat, and reduction of odor. The integration of algae cultivation in biogas plants can increase the overall efficiency and sustainability of the biogas production process, while providing additional economic revenues from the commercialization of algae-based bio-products. At the same time, nutrient uptake by microalgae reduces nutrient leakage into the environment. This chapter reviews the possibilities, available research and development, and perspectives of the algae utilization in high-tech biogas plants running on wastewater sludge, food waste, agricultural waste, or even energy crops, producing combined heat and electrical power in the order of 1 MW el .