An Austin Idea Could Help Solve Fracking’s Water Problem
By Ian Floyd
For Reporting Texas and the Austin American-Statesman
Hydraulic fracturing is a thirsty beast. On a typical day the process swallows up millions upon millions of gallons of fresh water that roustabouts mix with a cocktail of chemicals to inject into underground rock formations to liberate deposits of oil and natural gas. Water use at that volume is bad news for the parched places of the Earth and Texas in particular, where historic drought conditions have strained freshwater resources.
But relief may be on the way. University of Texas professor of chemical engineering Benny Freeman and his colleagues have developed a process they think will reduce the amount of fresh water used in fracking by recycling up to 50 percent more water than existing techniques.
In the five years since the start of the fracking boom began, the United States has become the global leader in the production of liquefied natural gas and the fastest-growing producer of oil. In October, for the first time since 1995, the month’s domestic oil production exceeded imports. Texas ranks first among the states in oil and gas production.
In 2012, fracking generated $62 billion in federal, state and local government revenue.
Yet fracking comes with the risks of using and potentially contaminating local water supplies and destroying roads used to truck supplies to and from the site, and it has been linked to earthquakes.
Proponents say Freeman’s state-of-the-art filtration system could be the next crucial step toward a game-changer that allows fracking wildcatters to economize on water costs while minimizing environmental damage. While the jury is still out (critics say widespread application of Freeman’s technique may be costly and impractical at this point), there is no denying the process represents something of a milestone in ongoing efforts to make fracking technology less environmentally intrusive.
Freeman’s process takes water that’s been used for fracking and pumps it through two specially coated membrane filters. The first is coarse and removes oils, chemicals and large contaminants like rocks. The second uses reverse osmosis, the same technology used to desalinate seawater, removing its salts and minerals. The result is a supply of recycled water ready to inject back underground to free more rock-bound pockets of oil and gas. Typically, the cleaner water, the more efficient the fracking process becomes.
“The amount of water that you can process with a given amount of energy will be as much as 50 percent higher with these treated membranes than without,” Freeman said.
The principals at Advanced Hydro, a Pflugerville-based startup, are confident enough about the process’ potential appeal in Texas and beyond that they are working to commercialize the technology, which they are marketing to investors for various applications, including fracking and desalinating water. While some applications have earned Advanced Hydro partnerships with companies ready to implement the technology, the purification system has yet to gain traction because of cheaper recycling alternatives, limitations on a membrane’s ability to desalinate and the still-low price of obtaining fresh water in many areas.
“Most often that salinity gets to be too high to treat with membranes,” said Gil Turner, the Gulf Coast account executive for Hydronautics, the company from which Freeman purchased the membrane filters used in the field trials. “Even if you could do it with membranes, the amount of water you recover is too little to be practical.”
Twenty-five years ago, Freeman started trying to increase the efficiency of filtration systems to clean oily water from the naval ship engines. That effort yielded innovative membrane coatings that Freeman said were his entry point to fracking while it was still in its infancy.
The big breakthrough came five years ago when Bryan McCloskey, then a graduate student in Freeman’s lab at UT, and Ho Bum Park, a postdoctoral researcher, discovered a new coating that worked better than the rest. The substance, called polydopamine, is a hydrophobic coating, meaning the filter is less attracted to water. The filter thereby resists clogging, or “fouling.”
McCloskey and Park “basically found a much more effective way to increase the fouling resistance of the membranes we were testing,” Freeman said.
Membranes coated with polydopamine increase water throughput, thus using less energy. The membranes are also easier to clean and last up to twice as long, said Dan Miller, a post doctoral researcher in Freeman’s lab.
Freeman estimates that about $1 million was spent on the research of this technology, which was funded through paid student fellowships from the National Science Foundation and grants from the U.S. Department of Energy. In UT’s initial negotiations with Advanced Hydro, Freeman received a stake in the company of less than 10 percent.
The fracking industry is clearly on the lookout for such advances.
“One of the biggest problems in the oil field is what to do with produced water,” said Tom Pankratz, editor of the Water Desalination Report, an industry newsletter. “Everybody’s looking for that ‘silver bullet.’ How do you treat it and reuse it beneficially or dispose of it as inexpensively as possible without doing any environmental damage?”
During the rock fracturing process, 10 to 30 percent of the water volume — called fracking flowback — is returned to the surface, according to Miller. “So we are still talking about … millions of gallons of water,” he said.
The flowback and produced water is toxic, containing oil, salt and an array of minerals and chemicals that must be removed before being returned to the environment or reused in further drilling. Techniques for doing so differ based on the chemical composition and geography of the well.
One of the most common techniques in Texas uses walnut-shell filters, named for their shape, and an oil separation pretreatment technique.
Dileep Agnihotri, CEO of Advanced Hydro, says Freeman’s filters work more efficiently and are a viable alternative in handling wastewater in many places in Texas, particularly those producing heavy oil, which tends to easily clog walnut-shell filters. The cost of membrane-based filters has been one of the main barriers to the adoption of membrane filter technology, he said.
Another, he noted, is that in some areas it is cheaper to buy fresh water, some of it from farmers selling agricultural water.
Advanced Hydro will try not only to recycle dirty water but to create its own water source .
Green Hydro LLC, a spinoff company of Advanced Hydro, will tap, treat, desalinate and sell brackish water — natural water with a high salt content — to fracking sites without immediate access to fresh water in Texas and New Mexico. In many cases the salt content must be lowered to an acceptable level that is unique to each well.
In some areas “the cost of fresh water is still very high,” Agnihotri said. To truck in water 20 miles or more, the price increases by about $1.50 per barrel he said. “We offer lower costs if you produce water on site using desalinated brackish water.”
In 2010, nearly 30,000 acre-feet, roughly enough to fill 15,000 Olympic swimming pools, of brackish water was used for oil and natural gas production purposes, according to a 2011 study by the Texas Water Development Board.
The company has negotiated a deal in West Texas to begin selling brackish water starting in February, Agnihotri said. Advanced Hydro also conducted a pilot study in conjunction with the U.S. Navy on a portable, easy-to-clean seawater desalination system.
Statewide, these applications of the membrane coating may not have a huge impact, said Dan Hardin, interim deputy executive administrator of water resources planning and information for the Water Development Board.
But in some rural counties, fracking “is a significant part of water use,” he said. “It can affect aquifers, water levels and other users. In that sense it could have a major impact.”