As concerns about safe disposal of heavy metals and other pollutants in Marcellus Shale drilling wastewater mount, a University of Pittsburgh team has received a federal grant for a solution that not only addresses the problem, but asks if another environmental bad boy–acid mine drainage–can be used to clean the drilling water.
The link between the two issues was highlighted by recent reports of a massive fish kill in Dunkard Creek, a West Virginia tributary of the Monongahela River. Nearby injection wells and mine treatment facilities are being investigated as causes of an algae bloom that wiped out aquatic life for 30 miles.
With each well using between one and four million gallons of
pressurized water and sand to fracture the shale and release natural
gas, minimizing waste water is a critical issue. Drillers are
responsible for storing the wastewater, which can have five times the
salinity of sea water. Radislav Vidic, chair of Pitts Swanson School Department of Civil and Environmental Engineering, says the $1.06 million research project will test a method to filter and re-use wastewater.
“We will test a way to precipitate barium (produced in drilling wastewater) as barium sulfate to make solids, and then filter them out,” he explains. The experiment will use acid mine drainage, available throughout the Marcellus Shale region. “The good thing is that acid mine drainage contains a lot of sulfates, so we are thinking about using that as a source of sulfates to precipitate the barium and strontium.
The project, funded by the university and the U.S. Department of Energy, will start in Pitt labs and move to field tests of a pilot program. The first phase is to ascertain the locations of acid mine drainage, put all the data in one place in a GIS-based system, then compare it to Marcellus Shale drilling sites,” says Vidic. Because natural gas prices are relatively low, he says, “we have a year or two years to solve this problem. He admits, however, that the Monongahela River cannot tolerate much higher levels of salinity than it already has. If salinity reaches 1,000 milligrams per liter, it cannot meet federal drinking water standards.
Vidic suggests that eventually, companies could employ a mobile wastewater treatment system that could be moved among a number of sites.
Source: Radislav Vidic, University of Pittsburgh
Writer: Chris O’Toole