Engineers Produce Electricity from Wastewater

We have seen the concept of recycled water in horticulture as well as in industries and residential areas where it has gained momentum over the past decade. Along with water, the demand for other limited natural sources such as coal, oil and natural gas will gradually expand, making it arduous to generate these necessities to the growing population. Our lives are threatened by the danger of these resources disappearing.

A new finding by a team of engineers from Oregon State University (OSU) comes as a solution for this. Their creation could help in turning the world's sewage treatments facilities into power plants. The technology can significantly improve the performance of microbial fuel cells (MFCs) that can be used to generate electricity directly from wastewater.

According to the engineers, this new technology can produce up to 10 to 50 times the electricity per volume than comparable approaches and 100 times more electricity.

It is believed that this new technology has a great potential in changing the way wastewater is being treated all across the globe, and is a better replacement to the age-old technique of "active sludge". Using wastewater by adopting this technique will produce a significant amount of electricity.

The journal Energy and Environmental Science carries this new finding that was funded by the National Science Foundation.

"If this technology works on a commercial scale the way we believe it will, the treatment of wastewater could be a huge energy producer, not a huge energy cost," said Hong Liu, an associate professor in the OSU Department of Biological and Ecological Engineering. "This could have an impact around the world, save a great deal of money, provide better water treatment and promote energy sustainability."

By including certain new concepts in this design, such as anode-cathode spacing, evolved microbes and new separator materials, the technology can produce more than 2 kilowatts per cubic meter of liquid reactor volume that exceeds anything else done with microbial fuel cells.

This approach of the engineers would be hampered if the system didn't qualify for the water treating department. But according to the team, it treats wastewater effectively when compared to other approaches that generate electricity from wastewater, and does not carry any environmental drawbacks, such as production of unwanted hydrogen sulphide or release of methane, a potent green house gas.

"The OSU system has now been proven at a substantial scale in the laboratory" Liu said. "The next step would be a pilot study. Funding is now being sought for such a test. A good candidate might initially be a food processing plant, which is a contained system that produces a steady supply of certain types of wastewater that would provide significant amounts of electricity."

According to OSU scientists, continued research should result in finding a more optimal use of necessary microbes, reduction in the material cost and improved function of the technology at commercial scales.

The approach may also have special value in developing nations, where access to electricity is limited, as a result of which sewage treatment at remote sites is difficult or impossible.