Researchers claim electrodialysis good for fracking reuse
Researchers from the Massachusetts Institute of Technology (MIT) and Saudi Arabia's King Fahd University of Petroleum and Minerals have claimed to have found an economical way to use electrodialysis for removing salt from water produced in hydraulic fracturing (fracking) for shale gas.In a report, MIT's John Lienhard and five co-authors said they had found that high-salinity water produced during fracking can be treated through a succession of stages of electrodialysis. The water could be cleaned up enough to enable its reuse in fracking operations, significantly reducing the amount of water needed from other sources, they said. The water could not, however, be cleaned to the point where it would be potable. Prior to desalination, chemical impurities in the water would need to be removed using conventional filtration.
Electrodialysis, had been available for decades but has not been considered a viable candidate for extremely high-salinity water.
"Electrodialysis is generally thought of as being advantageous for relatively low- salinity water," said Lienhard, but the team's research indicates that high-salinity water produced during fracking can be treated effectively through a succession of stages of electrodialysis.
The costs of installing an electrodialysis system compare favourably to other, widely used systems for dealing with produced water, according to the researchers. But there remained hurdles to be cleared before the process could be put into use. The application would require the development of new equipment. And the researchers were uncertain how well electrodialysis membranes would hold up under exposure to water containing traces of oil or gas.