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Pitt researchers contribute to sustainable water management strategies used in hydrofracturing

PITTSBURGH  (April 3, 2013) … Researchers at the University of Pittsburgh and Carnegie Mellon University are proposing simplified and less expensive methods to analyze potential flowback water from hydraulic fracturing, based on the level of chloride in geographic areas throughout Pennsylvania. The team's research, " Spatial and Temporal Correlation of Water Quality Parameters of Produced Waters from Devonian-Age Shale following Hydraulic Fracturing ," is the cover story in the March 19, 2013 issue of the journal  Environmental Science and Technology . The research was supported by the  U.S. Department of Energy National Energy Technology Laboratory .

Radisav D. Vidic, P.E., PhD , William Kepler Whiteford Professor and Chair, Department of Civil and Environmental Engineering and lead investigator, noted that while additional geological studies are warranted, the research indicates that the correlation between the drilling location (spatial) and when the wastewater is extracted (temporal) developed in this study can predict wastewater quality and guide the selection of management alternatives prior to extraction. 

According to Dr. Vidic, composition of flowback and produced water from hydraulic fracturing varies both over time and by location in areas throughout Pennsylvania, with the most pronounced differences between the southwest and north east regions. Furthermore, they also elucidated the role of chemical reactions that are governed by the frack fluid quality and solid-water interactions on the quality of water recovered in the early stages of well operation (flowback period) when majority of wastewater is collected.

"By analyzing well sites around the state we found trends that indicated what total dissolved solids would be found in a particular well," Dr. Vidic explains. "Even though there are various dissolved solids in different amounts in each well, we could correlate these amounts based simply on the amount of chloride in the wastewater, which was the dominant ion regardless of location."

The researchers found that concentrations of calcium, magnesium and bromide are higher in southwestern Pennsylvania, while concentrations of barium and strontium are higher in the northeast. They hypothesize that this may be the result of the geologic history of these deposits. 

"We can then analyze general trends in the geochemistry of the produced water and provide more comprehensive information to develop more sustainable water management plans. By knowing what waste will be generated at a given site over time, we can more effectively treat and reuse the wastewater, rather than utilizing new sources of freshwater that must be harvested and transported to the site. 

In addition to Dr. Vidic, the research group included Elise Barbot, PhD, Research Associate at the Swanson School's Department of Civil and Environmental Engineering; Kelvin B. Gregory, PhD, Assistant Professor in the Department of Civil and Environmental Engineering at Carnegie Mellon University; and Natasa S. Vidic, PhD, Assistant Professor of Industrial Engineering at the Swanson School. 



Contact: Paul Kovach