ABSTRACT Graphical abstract showing how oxygen availability affects pollutant removal and bioelectricity generation in LM, LM MFC, MFC, and AC MFC reactors. Forced aeration gives the best overall treatment and electrochemical performance. . This study investigated pollutant removal and bioelectricity generation under different oxygen availabilities, created by forced aeration and dense plant cover. Four 150 L working-volume reactors treating synthetic wastewater were operated as floating treatment wetlands (FTW), microbial fuel cells (MFCs), MFC-assisted FTWs (LM MFCs), and an aerated cathode MFC (AC MFC). The FTW-based configurations were planted with naturally developed Lemna minor (LM). All reactors were carried in batch mode using a well-established system, implemented as a late-season experiment. Regular monitoring included pollutant concentrations, redox potential, and voltage output. The AC MFC achieved the highest nitrogen removal among all configurations, reaching up to 100% NH4-N removal and 86% total nitrogen (TN) removal. Integrating the MFC with LM improved TN removal compared with the LM and MFC reactors (by 10%). COD removal was highest in the MFC (88%) and LM MFC (83%). Total phosphorus (TP) removal was enhanced by forced aeration, reaching 75%. The maximum voltage output was observed in the AC MFC (200 mV), although voltage generation was unstable and appeared sensitive to temperature and solar irradiance. Overall, the results highlight oxygen availability as a key driver shaping both treatment performance and electrochemical output in FTW-MFC systems.
Strycharz et al. (Mon,) studied this question.