A new hybrid device could provide sustainable energy while improving wastewater treatment. Researchers at the University of California – Santa Cruz have developed a solar-microbial device that combines a microbial fuel cell and a type of solar cell called a photoelectrochemical cell, which in essence makes the device self-sufficient. 

Yat Li, associate professor of chemistry at UCSC, led the research team. “The only energy sources are wastewater and sunlight,” she said in a press release. 

When fed with wastewater and illuminated with a solar simulator, the PEC-MFC device produced hydrogen gas at an average rate of .05 cubic meters per day. Simultaneously, the wastewater became clearer. 

And as the bacteria used up the organic matter in the wastewater, the hydrogen generation declined, therefore requiring a constant replenishment of wastewater to restore the electric current generation and hydrogen gas production. 

The research team is planning to scale up the device to make a larger 40-liter prototype continuously fed with municipal wastewater. If results from that version are promising, they will test the device at a wastewater treatment plant. 

Fang Qian, a Lawrence Livermore National Laboratory researcher, co-authored the study. “The MFC will be integrated with the existing pipelines of the plant for continuous wastewater feeding, and the PEC will be set up outdoors to receive natural solar illumination,” she said in the press release. 

Results and findings were published by the team in the American Chemical Society journal, ACS Nano.

http://news.ucsc.edu/2013/10/solar-microbial-device.html