Efficient electricity generation from sewage sludge using biocathode microbial fuel cell

Area of Science:

• Environmental Science
• Electrochemistry
• Microbiology

Background:

• Microbial fuel cells (MFCs) typically require expensive catalysts or catholytes for abiotic cathodes.
• High costs and limited efficiency hinder the widespread application of MFC technology.

Purpose of the Study:

• To investigate the efficacy of incorporating biocathodes into a three-chamber MFC system for electricity generation from sewage sludge.
• To evaluate the performance of MFCs with biocathodes in terms of power output, pollutant removal, and internal resistance.

Main Methods:

• A three-chamber MFC system was constructed and operated with sewage sludge as the substrate.
• Performance metrics including maximum power output, total chemical oxygen demand (TCOD) removal, and coulombic efficiency (CE) were measured.
• Microbial communities on the anode biofilm were analyzed using 454 pyrosequencing.

Main Results:

• The MFC with biocathodes achieved a maximum power output of 13.2 ± 1.7 W/m(3), significantly higher than previously reported values.
• The system demonstrated effective TCOD removal (40.8 ± 9.0%) and coulombic efficiency (19.4 ± 4.3%) after 15 days of operation.
• Lower internal resistance (36-46 Ω) was observed, contributing to the enhanced power density.

Conclusions:

• Biocathodes offer a promising alternative to abiotic cathodes in MFCs, leading to improved performance and reduced costs.
• The microbial community analysis revealed dominant phyla including Proteobacteria and Bacteroidetes, with specific genera like Rhodoferax and Ferruginibacter being abundant.
• This study highlights the potential of MFCs with biocathodes for sustainable energy generation and wastewater treatment.