Simultaneous algae-polluted water treatment and electricity generation using a biocathode-coupled electrocoagulation cell (bio-ECC).

How to utilize electrocoagulation (EC) technology for algae-polluted water treatment in an energy-efficient manner remains a critical challenge for its widespread application. Herein, a novel biocathode-coupled electrocoagulation cell (bio-ECC) with sacrificial iron anode and nitrifying biocathode was developed. Under different solution conductivities (2.33±0.25mScm and 4.94±0.55mScm), the bio-ECC achieved almost complete removal of algae cells. The maximum power densities of 8.41 and 11.33Wm at corresponding current densities of 48.03Am and 66.26Am were obtained, with the positive energy balance of 4.52 and 7.44Wm. In addition, the bio-ECC exhibited excellent NH-N removal performance with the nitrogen removal rates of 7.28mgLh and 6.77mgLh in cathode chamber, indicating the superiority of bio-ECC in NH-N removal. Pyrosequencing revealed that nitrifiers including Nitrospira, Nitrobacter, Nitrosococcus, and Nitrosomonas were enriched in biocathode. The removal mechanisms of algae in anode chamber were also explored by AFM and SEM-EDX tests. These results provide a proof-of-concept study of transferring energy-intensive EC process into an energy-neutral process with high-efficiency algae removal and electricity recovery.