This
study demonstrates the application of an algae-assisted microbial
fuel cell (AMFC) in biogas upgradation. A proof-of-concept lab-scale
biorefinery is presented that couples raw biogas upgradation with
dairy wastewater treatment using an integrated approach of a bicarbonate-based
integrated carbon capture and algae production system (BICCAPS) and
a microbial fuel cell (MFC). The treated biogas had a CH4 content of 85–93% with no traces of CO2, H2S, or NH3. The system was able to remove H2S and NH3 from biogas with high sulfide (961 to
2800 ppm) and ammonia (1300 to 2800 ppm) concentrations. The power
and current densities obtained from the MFC were 17.3 mW/m2 and 170 mA/m2, respectively. The normalized energy recovery
(NERV) from this process was 6.91 kW h/m3. The
CO2 captured in the form of bicarbonate led to a total
algal biomass production of 6.8 (±0.15) g/L. Integrating the
BICCAPS with an algae-assisted MFC makes the overall process more
sustainable, as it can simultaneously treat wastewater, generate bioelectricity,
upgrade biogas, and mitigate carbon (CO2) and nitrogen
(NH3) emissions.