High-rate ammonium removal and recovery and hydrogen production from wastewater using microbial electrolysis cell
Jorge Luque-Rueda, Pau Bosch-Jimenez, Martí Aliaguilla, Daniele Molognoni and Eduard Borràs Camps
This study presents an integrated approach combining microbial electrolysis cells (MECs) with three external ammonium extraction systems, Gas Diffuser (GD), Stripping Column (SP) and Thermally Assisted Stripping (SP + T), to enhance nitrogen removal and recovery from high-strength wastewater. Among the configurations, MECs operated at 0.75 V and integrated with SP + T achieved the highest performances, with current density of 8.8 A m−2, ammonium removal and recovery rates reaching 69.8 and 37.9 gN m−2 d−1, Faradaic efficiency of 74.9 % and specific energy consumption for ammonium recovery of 3.3 kWh kg−1N. The SP + T system boosted ammonia volatilization at the catholyte and accelerated ammonium transport across the cation exchange membrane, leading to improved removal and recovery performance. Concurrently, H2 generation reached 1557.6 L H2 m−3 d−1 with specific energy consumption of 31.4 kWh kg−1 H2. These results highlight that coupling MEC and SP + T is a promising configuration for efficient nitrogen recovery and renewable hydrogen generation, while demonstrating MECs as a sustainable technology for wastewater treatment and resource recovery.
