Microbes Cheaply Clean Fracking Wastewater, Create Energy
A new technology uses microbes to remove salt and organic contaminants from wastewater created by unconventional oil and natural gas drilling while simultaneously generating energy, say engineers at the University of Colorado, Boulder.
The new technique recovered more than 98 percent of the salts and 75 percent of the organic matter at a rate faster than current microbial processes -- all in one system that could be located on-site, according to the study.
It is premised on the chemistry of a battery, according to the researchers. The microbes eat the hydrocarbons in the wastewater and release energy that is turned into positively and negatively charged electrodes, which attract and remove the dissolved salt and produce excess energy that can be used to run equipment. The study was published in the current edition of the journal Environmental Science: Water Research & Technology.
"The beauty of the technology is that it tackles two different problems in one single system," Zhiyong Jason Ren, a CU Boulder associate professor of environmental and sustainability engineering and senior author of the paper, said in a statement. "The problems become mutually beneficial in our system -- they complement each other -- and the process produces energy rather than just consumes it."
Current water treatment techniques can require up to a dozen steps to clean and prepare the water for reuse, which gets complicated and expensive. This is why many companies choose instead to inject the wastewater deep underground. Oil and gas operations in the United States produce about 21 billion barrels of wastewater per year, according to the University of Colorado.
The disposal of wastewater is one of the leading criticisms some communities and environmentalists have of hydraulic fracturing due to concerns about water shortages, contaminating drinking water and earthquakes.
The CU team is currently working on scaling up the technology and has created a startup company, BioElectric Inc., to commercialize it. The original research was supported by the National Science Foundation.
In order to be successful in the market, the technology also needs to be competitive with what oil and gas companies are paying now to buy water to use for fracking, according to Casey Forrestal, the CU Boulder postdoctoral researcher who is the lead author of the paper.
A competitive price point may be easier for the new technology to reach in some states that are considering incentives and regulations requiring oil and gas companies to reuse wastewater.
An analysis last year found that just 1 percent of the water encountered by drillers is recycled and reused for hydraulic fracturing operations, while about 60 percent of produced water is reinjected into formations to encourage more hydrocarbon production, while 23 percent of it is destined for injection well disposal, according to the information and consulting firm PacWest Consulting Partners (EnergyWire, May 27, 2014).
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