Microbial cells to fuel the future
doi:10.1038/nindia.2008.188 Published online 28 April 2008
Researchers in Hyderabad have designed a special microbial fuel cell (MFC) that generates bioelectricity by degrading wastewater. This technology provides a dual benefit of wastewater treatment along with energy generation and provides access to cheap and eco-friendly energy sources.
Electricity generation from hydrogen has shown promise in recent years, though it has some inherent limitations like low production rate and use of secondary fuel cells. This led the researchers to focus on microbial fuel cells. They produced a chamber known as anodic chamber that contained anode with wastewater and bacteria (biocatalyst). The bacteria, which prefer to proliferate in acidic medium, feast on wastewater resulting in generation of bio-potential (voltage). A cathode was fixed next to the anode chamber. A glass wool membrane, which works as proton exchange membrane, was inserted between the anode and cathode.
The outer side of the cathode was exposed to air. The researchers added wastewaters to the MFC system and studied its bioelectricity generation potential and wastewater removal efficiency. In the first 37 hours, voltage output increased with time accounting for a maximum voltage of 212 millivolt (mV) along with wastewater removal efficiency of 60 per cent. Voltage approached maximum of 308 and 291 mV at pH 6 and 7 respectively.
"The MFC system will have wider application potential in effluent treatment plants (ETPs) in near future," says lead researcher S. Venkata Mohan from the Bioengineering and Environmental Centre of Indian Institute of Chemical Technology. Major advantages of energy from wastewater are the absence of pollutants and energy recovery with wastewater treatment, he adds.
- Mohan, V. S. et al. Biochemical evaluation of bioelectricity production process from anaerobic wastewater treatment in a single chambered microbial fuel cell (MFC) employing glass wool membrane. Biosens Bioelectron. 23, 1326-1332 (2008)