Hydrodynamic Optimization and Bioelectrochemical Performance of a Dual-Chamber Microbial Fuel Cell: A CFD-Assisted...

The optimization of hydrodynamic conditions in microbial fuel cells (MFCs) is critical to enhancing both pollutant removal and electricity generation. This study evaluates the impact of impeller-driven mixing applied to anaerobic MFCs on biomass suspension, dye degradation, and power output. Activated sludge (100-300 g/L, equivalent to 2.0-6.0 g/L TS) was combined with a synthetic dye solution and operated under stirring speeds of 25, 75, and 125 rpm. A CFD framework based on the Eulerian multiphase approach and the RNG k-ε turbulence model was implemented in ANSYS Fluent to simulate liquid-solid interactions, predict biomass distribution, and compare the results with experimental measurements. CFD predictions aligned closely with measurements (error < 3%). At 125 rpm, a homogeneous sludge suspension was achieved, preventing sedimentation and promoting optimal substrate-biofilm contact. Under these conditions, dye removal reached 78% and power density increased to 0.951 W/m². Reduced stirring (25 rpm) caused biomass accumulation at the bottom, lowering color removal to 35% and power density to 0.231 W/m².