Recovery of nitrogen and water from landfill leachate by a microbial electrolysis cell-forward osmosis system

Abstract

A microbial electrolysis cell (MEC)–forward osmosis (FO) system was previously reported for recovering ammonium and water from synthetic solutions, and here it has been advanced with treating landfill leachate. In the MEC, 65.7 ± 9.1% of ammonium could be recovered in the presence of cathode aeration. Without aeration, the MEC could remove 54.1 ± 10.9% of ammonium from the leachate, but little ammonia was recovered. With 2 M NH₄HCO₃ as the draw solution, the FO process achieved 51% water recovery from the MEC anode effluent in 3.5-h operation, higher than that from the raw leachate. The recovered ammonia was used as a draw solute in the FO for successful water recovery from the treated leachate. Despite the challenges with treating returning solution from the FO, this MEC–FO system has demonstrated the potential for resource recovery from wastes, and provide a new solution for sustainable leachate management.