Synergistic energy-water treatment enhancement in taper ceramic cathode microbial fuel cell coupled constructed wetland: Regulation mechanisms of electrical conditions and feeding manners

This study comprehensively investigates a novel taper ceramic cathode-based microbial fuel cell-constructed wetland (MFC-CW) system under diverse electrical conditions and feeding manners. The cathode, featuring a self-stabilizing ceramic pot integrated with carbon felt and activated carbon, significantly reduced internal resistance (minimum 156 Ω) while sustaining high open-circuit voltages (>565 mV) through enhanced oxygen diffusion and proton transfer while maintaining ion conductivity. Key findings demonstrate that continuous feeding mode outperformed batch operation in both pollutant removal and bioelectricity generation due to stable hydraulic conditions promoting proton migration. Optimal performance was achieved at an external resistance of 220 Ω, balancing power output (peak power output: 959.16 μW with scattered anodes) and nitrogen removal enhancement (48.68 % of TN). MFC-CW with anode consist of stainless steel mesh (SSM) cage filled with charcoal or graphite maximized COD removal (up to 224.17 mg/L) and voltage generation (597.85 mV). The system's scalability was validated through multi-anode configurations, with scattered anodes increasing power output by leveraging reduced electrode spacing. This work establishes operational guidelines for synchronizing wastewater treatment performance and bioelectricity production, highlighting the ceramic cathode's critical role in advancing sustainable MFC-CW applications. • Innovative taper ceramic-based cathode design enhances MFC-CW performance. • Maximum power output (959.2 μW) and reduced internal resistance (156.9 Ω) were achieved. • Enhanced TN removal by up to 48.7 % with MFC integration was verified. • Continuous feeding mode was superior to batch mode for energy and treatment efficiency.