Electricity generation from fermented primary sludge using single-chamber air-cathode microbial fuel cells.

Area of Science:

• Environmental Science
• Electrochemistry
• Biotechnology

Background:

• Microbial fuel cells (MFCs) offer a sustainable method for wastewater treatment and energy generation.
• Primary sludge is an abundant organic waste stream with potential for bioenergy recovery.

Purpose of the Study:

• To evaluate the feasibility of using fermented primary sludge as a fuel source in air-cathode MFCs.
• To optimize MFC performance by adjusting sludge fermentation and dilution parameters.

Main Methods:

• Single-chamber air-cathode MFCs were operated using fermented primary sludge.
• Sludge fermentation involved incubation at 30 °C for 9 days.
• Fermentation supernatant was diluted with primary effluent, with and without phosphate buffer, to assess its impact on MFC performance.

Main Results:

• Fermentation significantly altered sludge characteristics, increasing soluble chemical oxygen demand (sCOD) and volatile fatty acids (VFAs).
• MFCs fueled with fermented sludge and primary effluent achieved a maximum power density of 0.32 W/m², higher than primary effluent alone (0.24 W/m²).
• Addition of phosphate buffer further enhanced power density to 1.03 W/m², with sCOD removal rates between 84-94% and coulombic efficiencies of 18-57%.

Conclusions:

• Fermented primary sludge is a viable substrate for electricity generation in MFCs.
• Dilution with primary effluent and phosphate buffer addition are effective strategies to improve MFC performance.
• This study highlights the potential of sludge fermentation for sustainable bioenergy production and wastewater treatment.