Scientists unlock key to turning wastewater and sewage into power
As renewable energy sources goes, solar rays have historically hogged the limelight.
But two Virginia Tech researchers have stolen the spotlight from the sun by discovering a way to maximize the amount of electricity that can be generated from the wastewater we flush down the toilet.
An article published in Scientific Reports detailing their findings speaks to a growing sustainability movement to capture energy from existing waste to potentially make treatment facilities more energy-efficient.
Xueyang Feng and Jason He traced bacteria, which led them to discover that the working relationship between two specific substrates produced more energy than either did separately. This work will help take the mystery out of how electrochemically-active bacteria create energy. It could help in the development of new treatment system called a microbial fuel cell.
“Tracing the bacteria gave us a major piece of the puzzle to start generating electricity in a sustainable way,” said Feng, an assistant professor of biological systems engineering. “This is a step toward the growing trend to make wastewater treatment centers self-sustaining in the energy they use.”
The discovery is important because not all organics perform the same job in the same way. Some work because they are food for the electricity-generating bacteria while others are good at conducting energy.
While one substrate known as lactate was mainly metabolized by its host bacteria to support cell growth, another substrate known as formate was oxidized to release electrons for higher electricity generation.
The team found that when these two substrates are combined, the output of energy is far greater than when they are working separately. The organics work in tandem with receptors in fuel cells, and while research using microbial fuel cells is not new, the kind of organics that Feng and He used was novel in generating electricity because they were able to measure the symbiotic nature of two particular organics.
The unique methodology that allowed them to trace the metabolic pathways of the different strains of bacteria, called carbon 13 pathway analysis, was the first time this type of isotope labeling process was used in measuring metabolism in microbes, the researchers said. The analysis works by creating a non-radioactive isotope on a carbon group that is visible through a mass spectrometry.
Continue reading at Virginia Tech News.
Wastewater treatment image via Shutterstock.