Approximately 10 to 30 percent of the total water used in the hydraulic fracturing process returns to the surface as what is called flowback water. This remaining water, which contains naturally occurring elements as well as certain chemicals used during the extraction process, is captured and stored for treatment or disposal. Emerging technology allows operators to use fewer chemicals and recycle up to 100 percent of their flowback water in one of several ways.
One option is to treat the flowback water on site for reuse with an oxidation system that removes the dissolved solid material from the flowback. Another disposal option involves injecting the excess water into permitted deep injection wells off site. A third option is for flowback water to be disposed into bodies of existing water; however, the Pa. Department of Environmental Protection dictates that flowback must meet state drinking water standards and be treated to have a total dissolved solids (TDS) concentration of 500 parts per million or less before being discharged into bodies of surface water.
As part of the application process to drill a well, operators must identify where excess water or flowback will be treated and stored. Before drilling can begin, operators are required to test all water wells and surface waters within 2,500 feet of any proposed drill. These test results serve as a baseline for any future water quality tests.