That’s why
Together, He and his partners hope to develop commercial applications in the growing global market for water systems that operate with a small carbon footprint.
The bioreactors that crowd He’s labs are built around a phenomenon that was established 100 years ago in
If all goes well, He’s systems will perform three functions at once:
—Purify wastewater using bacteria.
—Produce electricity.
—Desalinate a separate supply of seawater in the same three-chamber bioreactors.
“”This is not a perpetual motion machine. The science is proven. It’s just taking energy that’s untapped and using it,”” said
He, who left a post at the
He and Drew are looking for new allies to help them win federal grants so they can develop and test larger reactors.
He wrote his doctoral thesis on microbial fuel cells, the technology underlying his reactor.
Classic microbial fuel cells have two chambers. And like a battery, one side has a positive electrode and the other a negative. One side is filled with bacteria and wastewater, which triggers the circuit.
The big innovation for He and Drew was the addition of a third chamber that holds salty seawater. Salt molecules, or sodium chloride, dissolve naturally in water. Permeable membranes separate the third chamber from the other two, allowing positively charged sodium atoms to migrate toward the electrode in one chamber while negatively charged chloride particles seep into the second. That removes the salt, molecule by molecule — at least in the lab.
So far, it appears unlikely that the system can remove every last trace of salt from water. But at the very least, He said his system could create a pre-desalination process that removes most of the salt and reduces the energy needed to strip out the rest.
He was hired at UW-Milwaukee to help fill one of the most glaring deficiencies in the region: While the area has dozens of water-technology companies, the
It wasn’t until energy prices rose in recent years that scientists revived an interest in energy-producing bacteria, He said. Some two dozen research groups are at work on similar technologies in the U.S., but more are researching parallel applications in Chinese universities, said the Chinese-born He.
“”I’m hardly the first,”” He said.