Carbon Neutral Electricity Production from Municipal Solid Waste Landfill Leachate Using Algal-Assisted Microbial...

Area of Science:

• Environmental Science
• Biotechnology
• Renewable Energy

Background:

• Municipal solid waste (MSW) leachate poses environmental challenges.
• Microbial fuel cells (MFCs) offer a method for wastewater treatment and energy generation.
• Algal cultivation can be integrated with MFCs for enhanced performance.

Purpose of the Study:

• To demonstrate the feasibility of an algal-assisted microbial fuel cell (AAMFC) for simultaneous MSW leachate treatment, bioelectricity generation, and algal lipid production.
• To investigate the impact of MSW leachate concentration on AAMFC performance.
• To evaluate the effect of salinity on AAMFC efficiency and algal biomass composition.

Main Methods:

• A double-chamber AAMFC was designed, with Synechococcus sp. and MSW leachate in the cathode and anaerobic microflora in the anode.
• The AAMFC was operated with varying concentrations of MSW leachate (up to 50%).
• Salinity was adjusted using NaCl (30 mM) to assess its influence on power density, current density, and biomass characteristics.

Main Results:

• Treating 50% MSW leachate yielded a maximum power density of 95.63 mW/m², current density of 2.48 A/m², and biomass concentration of 2.54 g/l.
• Algal growth in the cathode increased oxygen concentration from 5.5 to 8.6 mg/l.
• Adding 30 mM NaCl to 50% leachate further boosted power density to 110.92 mW/m² and current density to 5.169 A/m², while increasing lipid and protein content.

Conclusions:

• The AAMFC is effective for the simultaneous treatment of MSW leachate, bioelectricity generation, and algal lipid production without external aeration.
• Algal cultivation enhances oxygen levels in the cathode, improving MFC performance.
• Salinity adjustment can optimize AAMFC efficiency and enhance the yield of valuable algal lipids.