Researchers at University of California, Santa Cruz have combined a microbial fuel cell (MFC) with a photoelectrochemical cell (PEC) to create hydrogen gas from sunlight and sewage. The device solves two problems including the treatment of wastewater and the creation of hydrogen gas for autos.
According to , “In effect, the MFC component can be regarded as a self-sustained ‘bio-battery’ that provides extra voltage and energy to the PEC for hydrogen gas generation. ‘The only energy sources are wastewater and sunlight,’ Li said. ‘The successful demonstration of such a self-biased, sustainable microbial device for hydrogen generation could provide a new solution that can simultaneously address the need for wastewater treatment and the increasing demand for clean energy … ‘
“…When fed with wastewater and illuminated in a solar simulator, the PEC-MFC device showed continuous production of hydrogen gas at an average rate of 0.05 cubic meters per day, according to LLNL researcher and coauthor Fang Qian. At the same time, the turbid black wastewater became clearer. The soluble chemical oxygen demand–a measure of the amount of organic compounds in water, widely used as a water quality test–declined by 67 percent over 48 hours.”
The researchers go onto say that they intend to scale up their laboratory experiment into a 40-liter prototype and if all goes well, they will then move their efforts to a full-scale wastewater treatment plant.