Briny Pool Bacteria Can Clean Up and Power Up
Warm and salty wastewater is a by-product of many industries, including oil and gas production, seafood processing and textile dyeing. KAUST researchers are exploring ways to detoxify such wastewater while simultaneously generating electricity. They are using bacteria with remarkable properties: the ability to transfer electrons outside their cells (exoelectrogenes) and the capacity to withstand extremes of temperature and salinity (extremophiles).
The researchers, led by Pascal Saikaly, used water collected from three deep-water brine pools in the Red Sea to fill prototype microbial electrolysis cells (MECs), also known as fuel cells. “The Red Sea brine pools are good places to find extremophilic bacteria because they are among the world’s most extreme natural environments, with salinity up to 25% and temperatures higher than 46°C,” explains lead author and former PhD student and postdoc of KAUST, Noura Shehab. “However, their potential for electricity generation has not previously been explored.”
Typically, MECs take the form of glass bottles, which are filled with wastewater, and contain sterile graphite and stainless-steel electrodes. “Any exoelectrogenic bacteria present can oxidize organic matter in the wastewater, generating electrons that are transported to the positive electrode. When a small voltage is applied to the system, the electrons combine with protons in the water at the negative electrode, producing hydrogen gas,” explains coauthor Krishna Katuri. Thus, they simultaneously clean the water and generate hydrogen, a clean, transportable fuel.
Image: The MECs comprise glass bottles of wastewater that contain (a) the MEC anode or working electrode, (b) the reference electrode and (c) the cathode or counter electrode. (Credit: © 2017 KAUST)
Source: ENN November 6, 2017
From: King Abdullah University of Science & Technology (KAUST),