No. 135: Utilizing electricity generating microorganisms to the treatment of plant effluent (October 29, 2012)

Technology:

Tokyo University started the research to develop a system that utilizes electricity generating microorganisms for the treatment of effluent from plants in alliance with Tokyo University of Pharmacy and Life Sciences, Panasonic, and Sekisui Chemical. The system will generate power necessary to run the facility while treating organic substances in the effluent. It is expected to reduce the power consumption by up to 80%. They are scheduled to start the substantiative experiment in 2014 and put the system into practical use in 7-8 years.

Several microorganisms that emit electrons stored inside exist in the natural world. Kazuhito Hashimoto of Tokyo University and Kazuya Watanabe of Tokyo University of Pharmacy and Life Sciences built a fuel cell using several electricity generating microorganisms. They applied microorganisms to the metal surface of the negative electrode and immersed it in the effluent to generate electrons. In the experiment, they used one liter of effluent and eliminated 80% of organic substances in six hours, and generated electricity of 80-500 milliwatts. The research team plans to develop a system that can treat one ton of effluent in 24 hours by enlarging the size of a cell and improving the generation efficiency through modified combination of microorganisms and upgraded electrode.

The new system does not need equipment to mix effluent because the microorganisms used in the system can live without oxygen. At the same time, the new system creates about one third of the existing effluent treatment facility because the propagation of microorganisms is rather small. The same kind of research is under way in the U.S. Australia, Great Britain, and Korea. Kazuhito Hashimoto of Tokyo University predicts that an independent effluent treatment system without energy supply may be viable. The new system will solve the energy-saving problems that advanced countries have in common and create a big market in developing countries in need of improving electricity infrastructure.

The new system for the treatment of plant effluent utilizing electricity generating microorganisms. It does not need equipment to mix effluent because the microorganisms used in the system can live without oxygen.