As fracking has exploded across the country, so have toxic ponds of salty and contaminated water that litter places like North Dakota and Texas.
Now, a team of researchers may have come up with process they believe will treat this wastewater, helping address one of the industry's biggest headaches.
Writing in the journal Environmental Science Water Research & Technology, the University of Colorado Boulder scientists described their invention of a way to remove both salts and organic contaminants from fracking wastewater using microbes that gobble up the latter, leading to a chemical reaction that does away with the former.
The process takes advantage of the fact that the contaminants found in the wastewater contain energy-rich hydrocarbons, the same compounds that make up oil and natural gas. The scientists introduce microbes into the waste, which eat up the hydrocarbons, producing an electric current that removes the salt.
"The beauty of the technology is that it tackles two different problems in one single system," said Zhiyong Jason Ren, a CU-Boulder associate professor of environmental and sustainability engineering and co-author of the paper.
"So far, we have been able to clean up the water so that it can used in irrigation, toilet flushing," Ren told CBS News. "It can be used for anything except drinking at this level. If we can use reuse the water, the companies don't need to buy new water and they could even make money from selling it to other users like farmers."
Fracking - the process of injecting a slurry of water, sand and chemicals into wells to remove oil and gas - has expanded to 33 states and is used in over 90 percent of new oil and gas wells. The process uses huge amounts of water, which has raised alarm bells as places like California are hit by drought. The process also produces 100 billion gallons to as much as 800 billion gallons of wastewater a year.
The EPA has responded by launching a nationwide study to examine the impacts of the wastewater - which can contain total dissolved solids, fracturing fluid additives, metals, and naturally occurring radioactive materials - on sources of drinking water.
Until now, the industry hasn't come up with a fool-proof way to treat the water.
Along with storing the wastewater in ponds, much of it is treated to be reused in the field. But that treatment process typically requires multiple steps - sometimes up to a dozen. Other times the wastewater is injected deep underground, which has been blamed for setting off minor earthquakes in Ohio and Oklahoma.
Ren's breakthrough has gotten rave reviews from the industry, in part because it is a one-step process and in part because rather than consuming energy to function, it actual ends up with a net gain of energy, as the microbes release the energy stored within the hydrocarbons as they break them down. This helps turn the wastewater into a sort of battery that can be used to power on-site machinery and help make up for the higher cost of the process.
"This waste water treatment method is an exciting example of how researchers are driving technological innovations that will enhance the development of our energy resources and even develop a new source of energy as a byproduct," Randy Hildreth, the Colorado director of Energy In Depth said. "This kind of solutions-driven research is an important contrast to the political campaign being waged against energy development by 'ban fracking' groups, who routinely make exaggerated claims about water use in the West to scare the public."
Stanford's Rob Jackson, an environmental scientist who has done extensive research on fracking and wastewater, said the idea was interesting but he doubted it could be deployed on a large scale.
"Call me skeptical that we'll be treating a trillion gallons of oil and gas wastewater a year in the U.S. using approaches like this," he said. "It's too expensive, when companies can deep inject wastewater for a few dollars a barrel. It would definitely not be cost-effective on a site specific basis."
Jackson also said the other challenge would be disposing of the waste that comes from treating all this wastewater.
"What you do with concentrated waste materials? Where do the salts go, the brines left over from the treatment?" Jackson asked. "Do they go to a landfill? They have to be taken somewhere."
To tackle some of those concerns, Ren and his colleague Casey Forrestal co-founded a startup company called BioElectric Inc. a year-and-a-half ago. They are now exploring how to scale up the technology while keeping costs down. One boost could be the fact that several states are considering legislation requiring oil and gas companies to reuse their wastewater.
They said much of the waste could be reused on site and that their integrated approach will be much cheaper than those used currently, which use separate processes to treat the salt and the other toxins.
"This reduces the capital costs," Ren said. "For operational cost, our system doesn't consume external energy but produces some extra energy through electrochemical reactions. We also are working on making the system automatic and remotely controlled, saving labor costs."