Wastewater treatment plants could generate electricity

Over the past 20 years, nearly three-fourths of human-caused emissions came from the burning of fossil fuels. Increasing pollution and decreasing fossil energy resources encourage scientists to look for new clean and sustainable alternative energy resources. Microbial fuel cells, which are also being researched at KTU laboratories have broad usage possibilities and are one of the cleanest known energy sources. MFCs are powered by living microorganisms with clean and sustainable features; they can generate electricity from broad range of organic substrates under natural conditions.

"Microbial fuel production is probably the only technology, in which the electricity is being generated from oxidation of organic compounds in room temperature. In other words, there is no need to burn anything, and the process is not depending on sunlight," says Dr Kristina Kantmnien? researcher at KTU Faculty of Chemical Technology.

According to KTU researchers, MFC technology is unique because of its multifunctional application: for example, wastewater and slime, collected in wastewater treatment plants can be also used as food for bacteria. Integration of MFC into wastewater treatment system would significantly reduce the usage of electrical energy for its exploitation and would turn the plant into the closed ecosystem. The energy surplus produced by MFC might be integrated into the electricity grid and used elsewhere.

Although the idea that microorganisms can generate electricity was introduced in 1911, it became more actively investigated in the 2000s. Groups of researchers around the world are working with the MFC technology, attempting to improve the efficiency of the cells.

KTU researchers are testing the qualities and biocompatibility of MFC anodes, as the efficiency of microbial fuel cells by large part depend on them. In the framework of interdisciplinary research project "Innovative microbial fuel cells for sustainable production of bioelectricity" (MicrobElas) KTU researchers have developed a MFC prototype, which uses modified graphite felt as an anode.

"The modification of the anode allowed to increase the cell voltage; it is 20 percent higher than that of the control MFC with the usual anode. Although we are researching this technology only for a year, the first results are really inspiring," says Kantimien?.

The researchers predict that although MFC technology will not displace other sources of renewable energy, it could be beneficial in the small wastewater treatment plants or in remote regions where electrical energy supply is limited.

In May, the results of the research will be introduced in the Topical Meeting of International Society of Electrochemistry in Vilnius.