Self-Supplied Ammonium Bicarbonate Draw Solute for Achieving Wastewater Treatment and Recovery in a Microbial Electrolysis Cell-Forward Osmosis-Coupled System

Abstract

This study has presented a proof-of-concept system for the self-sustained supply of ammonium-based draw solute for wastewater treatment through coupling a microbial electrolysis cell (MEC) and forward osmosis (FO). The MEC produced an ammonium bicarbonate draw solute via recovering ammonia from a synthetic organic solution, which was then applied in the FO for extracting water from the MEC anode effluent. The recovered ammonium could reach a concentration of 0.86 mol L–1, and with this draw solution, the FO extracted 50.1 ± 1.7% of the MEC anode effluent. The lost ammonium during heat regeneration could be supplemented with additional recovered ammonium in the MEC. The MEC achieved continuing treatment of both organic and ammonium in the returned feed solution mixed with fresh anolyte, although at lower efficiency compared to that with completely fresh anolyte. These results encourage further investigation to optimize the coordination between MEC and FO with improved performance.