Electricity is a form of energy associated with the presence of electrically charged particles (e.g. electrons). It is typically generated at power stations by a movement of a magnet through a loop of wire; the movement is driven by heat engines fuelled by chemical combustion or nuclear fission but also by other means such as the kinetic energy of flowing water and wind. Electricity can be also produced by collecting the energy of the sun in photovoltaic cells or geothermal power. Scientists are currently researching new technology of electricity generation using bacteria and waste or contamination.
Bacteria are present everywhere, even in contaminated groundwater. They “eat” the organic contaminants degrading them to carbon dioxide, electrons and protons. These electrons then have to be transferred from bacteria in order to complete the degradation. It is a perfect opportunity to collect these electrons and also enhance the bacterial degradation of contaminants. We could place an electrode (anode) under the ground into contaminated groundwater and it would accept electrons released by bacteria. As the electrons are transported via the wire and resistor to the second electrode (cathode), electricity is produced.
The amount of electricity produced from this process is small (one “bacterial battery” like this would not be able to power a house) but it is more beneficial to the environment when compared with the technologies currently used in clean up of contamination. Today’s techniques for pollution removal consume electricity, whereas “bacterial batteries” produce a small amount of it, making it more sustainable. Petra Hedbavna, early-stage researcher at the University of Sheffield, has been examining this technology in the lab and the first results look promising. Nevertheless, there is still a lot of work to be done by the scientists before the “bacterial batteries” are applied in the field.
Schreiberová O, Hedbávná P, Cejková A, Jirků V, & Masák J (2012). Effect of surfactants on the biofilm of Rhodococcus erythropolis, a potent degrader of aromatic pollutants. New biotechnology, 30 (1), 62-8 PMID: 22569140