A new method for treating oil and gas wastewater aims to make the treatment process both simpler and smarter, making it easier to reuse or dispose of the water.
Developed by engineers at the University of Colorado Boulder, the process can simultaneously remove both salts and organic contaminants from the wastewater. At the same time, it produces additional energy that can be used on site to run equipment.
The researchers are hoping to commercialize the technology in the future.
The new technique relies on a microbe-powered battery that takes advantage of energy-rich hydrocarbons in the produced water.
"Instead of the traditional battery, which uses chemicals to generate the electrical current, we use microbes to generate an electrical current that can then be used for desalination," explained lead author Casey Forrestal, a CU-Boulder postdoctoral researcher.
Microbes used in the treatment process eat the hydrocarbons and release their embedded energy. This is then used to create a positively charged electrode on one side of the cell and a negatively charged electrode on the other, essentially setting up a battery, CU-Boulder said.
Salt dissolves into positively and negatively charged ions in water, allowing the cell to remove the salt in the wastewater by attracting the charged ions onto the high-surface-area electrodes, where they adhere.
"Right now oil and gas companies have to spend energy to treat the wastewater. We are able to treat it without energy consumption; rather we extract energy out of it," commented senior author Zhiyong Jason Ren, a CU-Boulder associate professor of environmental and sustainability engineering.
The new treatment technology is known as microbial capacitive desalination. Details of the process have been published in the journal Environmental Science: Water Research & Technology.