Synergistic integration of electrocoagulation and algal cultivation to treat liquid anaerobic digestion effluent and accumulate algal biomass

• Electrocoagulation was used to efficiently pretreat AD effluent for algal culture.
• Chlorella vulgaris was the preferred strain to culture on the EC treated AD effluent.
• 5% CO2 facilitated algal biomass accumulation.
• Dissolved iron from electrocoagulation enhanced algal lipid accumulation.

An integrated system of electrocoagulation and algal cultivation was developed to treat a high strength wastewater—anaerobic digestion liquid effluent for reclaimed water and value-added algal biomass production. The integrated system synergistically takes advantages of both electrocoagulation and algal cultivation to enhance the efficiencies of wastewater treatment. The electrocoagulation treated wastewater had low turbidity with better light penetration (108 NTU) to enable algal growth. The algal cultivation had high removal efficiencies of phosphorus (99.4%) and nitrogen (88.2%). The dissolved iron in the electrocoagulation treated wastewater enhanced lipid accumulation of the algae. The results present that total phosphorus and nitrogen in the reclaimed water were 0.78 g L−1 and 35.5 mg L−1 respectively, and the harvested algal biomass had 35% of lipid, 53% of protein, and 6.4% of carbohydrate. This study concluded a new route for agricultural wastewater treatment that turns wastewater from an environmental liability into a valuable asset.

Growth of different algae on EC water. Blue square stands for Scenedesmus dimorphus, red triangle stands for Chlorella vulgaris, green diamond stands for Chlamydomonas reihardtii.Figure optionsDownload as PowerPoint slide