A membrane-based filtration system being developed by researchers at the University of Texas at Austin (UT) could improve the efficiency of mobile water recycling systems used in conjunction with hydraulic fracturing (fracking) activities.
The high-efficiency filters may "significantly reduce" the amount of water and energy that fracking requires, the researchers said.
Professor Benny Freeman and his research team in the McKetta Department of Chemical Engineering recently completed a study that shows the team's filter can produce up to 50% more water for reuse compared with other filtration systems, greatly reducing demand for fresh water. In addition to producing a higher volume of purified water, the new filter system also operates at lower pressure than traditional systems, yielding significant energy savings, the researchers said. The findings were recently published in the Journal of Membrane Science.
"Recycling flowback water on site offers a cost-effective solution that conserves water and energy, saves roads from wear and tear and keeps production costs down," said Dan Miller, a UT Austin researcher on Freeman's team who helped develop the filtration system as a graduate student. "Everyone who uses water and natural gas can benefit from this technology."
The pilot study tested a system of specially coated membranes, which are pliable sheet-like structures made out of plastic that act as a barrier, to filter contaminated water that returns to the surface after it is pumped down a well during fracking.
The advantage is a patented coating that makes membranes more resistant to damage caused by contaminants, also known as fouling. Mixtures of salt, oils and other particlesoften clog membranes and cause significant, irreversible deterioration that shortens their lifespan. The coating, which helps membranes last longer, is a water-based solution that can be easily applied to membrane surfaces by simply rinsing it through the recycling system.
The water recycling system is licensed by UT to Advanced Hydro Inc., which was founded by Freeman in 2009.
Freeman has received funding for water purification research from various public and private entities including the U.S. Department of Energy and the National Science Foundation. He has also served as a consultant to several companies and is a fellow of several organizations, including the American Chemical Society, the American Institute of Chemical Engineers and the American Association for the Advancement of Science.
UT researchers early this year found that oil and gas producers are using more water for fracking, but they're also recycling more, making it important to distinguish between water "use" and "consumption" (see Shale Daily, Jan. 18).