When Pennsylvania prohibited drillers from taking their wastewater to water treatment facilities in 2011, the industry needed to look for other solutions.
In some areas of the country, including Pennsylvania, the wastewater from drilling activities contains fracturing chemicals, toxins and naturally occurring radioactive substances, such as radium.
Duke University researchers discovered a process that would permit oil and gas drillers to combine the flowback waters from fracking with salty water, including the acid drainage from mining.
The researchers combined wastewater from the Marcellus shale and acid drainage materials from the Western Pennsylvania mining industry.
They hypothesized that the salts, metal and radium would form solids leaving reduced salinity water that could be used in other fracking operations.
The process does present potential problems because spills of remaining water, contaminated with chemicals and toxins, could get into shallow aquifers.
Regardless, dealing with solid waste is safer than liquid and the amount of solids produced is manageable. The proposed method still needs to be field tested.
Since the freshwater shortage is becoming a critical factor in oil and gas industry, other approaches are also being pursued.
These options include recycling flowback water, designing ways to minimize the water needed, and looking at other liquids to crack the rock.
Centralized treatment for recycling wastewater from fracking activities within a surrounding area is another option that shows promise. Up to 60% of the water injected into a wellhead will quickly discharge back out of the well.
Subsequently, during the life of the wellhead, upwards of 100,000 gallons per day will be discharged – this is the major source of wastewater from a well.
Over a potential 20 year lifespan of the well, short terms solutions such as trucking water long distances, with potential collateral damage, and treating wastewater for reuse fail to address the critical long-term environmental and public concerns.
Centralized wastewater management can process both the flowback wastewater and the production wastewater from wells within a 40-50 miles radius.
In the wastewater recycling process, the originating well is identified and its wastewater is processed to match the usage requirements for a receiving well.
The recycled water is then piped to the recipient well site. The centralized treatment facility is capable of providing a wider range of treatment options than a mobile treatment plant.
In addition to the well wastewater, the centralized plant can process other sources of wastewater such as abandoned mines, storm water control basins, municipal treatment plants and cooling water from power plants.
This integrated network for treating wastewater would help fulfill mandates from Pennsylvania’s environmental agencies for increased use of recycled water for fracking.