Effect of C/N ratio and salinity on power generation in compost microbial fuel cells

- Potential of combining MFC and anaerobic composting of organic matter was demonstrated.
- Biodegradation in the working cMFCs was greater up to 8% as compared to a control system.
- cMFCs with lower C/N ratio and salinity led to higher power output.
- A maximum power density of 5.29 mW/m2 (71.43 mW/m3) was achieved.

In this work, compost Microbial Fuel Cells (cMFCs) were used to generate electricity from a mix of fruit and vegetable wastes, and soil with different C/N ratios and salinities. Experiments were carried out in 500 mL cMFCs equipped with carbon felt anodes and manganese dioxide cathodes. The cMFCs were loaded with fresh compost and operated at 20-23 °C for up to 97 days. The low C/N ratio (C/N 24) had a greater power production with a maximum power density of 5.29 mW/m2 (71.43 mW/m3), indicating a more favorable condition for microbial growth. High-saline cMFCs produced lower power, suggesting that their level of salinity (10 g/L of NaCl) inhibited electricigenic microorganisms. The closed-circuit cMFC showed an improved degradation of organic matter by 6% to 8% compared to the control MFC operated in an open circuit mode (no external resistor attached).