EPA has published a proposed rule to establish pretreatment standards that would prevent the discharge (zero discharge) of pollutants in wastewater from onshore unconventional oil and gas extraction (UOG) facilities to publicly owned treatment works (POTW). 80 Fed. Reg. 18557 (April 7, 2015). Essentially, no wastewater from a hydraulically fractured well may be sent to a POTW.
The pretreatment standards for existing sources (PSES) and new sources (PSNS) prohibit the indirect discharge of wastewater pollutants associated with onshore UOG extraction facilities. The sources of the wastewater are those associated with production, field exploration, drilling, well completion, or well treatment for unconventional oil and gas extraction. The wastewater includes produced water (which includes formation water, injection water, and any chemicals added downhole or during the oil/water separation process), drilling muds, drill cuttings, and produced sand. These terms are all defined in the rule.
Generally, this type of wastewater is managed through disposal in underground injection wells, reuse in subsequent fracturing jobs, or transfer to a privately owned wastewater treatment facility. In Pennsylvania, where underground injection is difficult due to the tightness of geologic formations, UOG wastewater was sent, for a time, to POTWs. However, this practice was banned by state regulation. EPA found that, at this time, there are no known discharges to POTWs from UOG extraction in the United States. Thus, proposing ‘zero discharge’ as PSES and PSNS does not seem to impact the industry.
EPA stated that direct discharges to waters of the United States had been adequately regulated since 1979. However, there were no requirements relating to ‘indirect discharges,’ i.e., those through a POTW. EPA felt this rule was necessary as this type of wastewater is generated in large quantities and could contain constituents that are potentially harmful to human health and the environment, such as high concentrations of total dissolved solids (TDS), organic chemicals, inorganic chemicals, metals, and naturally-occurring radioactive materials.
Comments on the proposed rule must be received on or before June 8, 2015.