Optimization modeling and economics assessment on simultaneous struvite and bioelectricity production from waste nutrient solution in the microbial fuel cell

Abstract

Several Sustainable Development Goals (SDGs) emphasize community well-being and environmental health. Addressing food and energy demands while ensuring a clean environment remains a global challenge. This study investigates nutrient recovery as struvite and bioelectricity generation from nutrient-rich wastewater using a dual-chamber microbial fuel cell (MFC). Response Surface Methodology with Central Composite Design (CCD) optimized Phosphorus (P) recovery at minimal cost. Simulation parameters, including the N:P ratio, chemical oxygen demand (COD), and cathodic aeration rate, were tested. Results showed that P recovery efficiency was influenced by the N:P ratio and COD, while power density was primarily impacted by COD. Optimized conditions of N:P = 1, COD = 3000 mg/L, aeration = 150 mL/min achieved 90 % P recovery as magnesium ammonium phosphate hexahydrate (struvite, MgNH₄PO₄·6H₂O) with a power density of 860 mW/m². The estimated cost based on CCD simulations was 2.5–2.6 USD/m³ within a 5 % deviation under optimal conditions of N:P = 2, COD = 3000 mg/L, aeration = 150 mL/min. These findings highlight the potential of integrating MFCs into wastewater treatment plants (WTPs) for nutrient recovery, COD reduction, and bioelectricity production. This approach offers a viable solution for sustainable wastewater management but requires careful assessment of Technology Readiness Level (TRL) and System Readiness Level (SRL) for large-scale implementation.