As part of its Final 2010 Effluent Guidelines Program Plan, EPA recently announced its intent to develop pretreatment requirements for discharges of wastewater from shale gas extraction to sewage treatment plants.
Shale gas extraction involves hydraulic fracturing or “fracking” – the injection of large amounts of water mixed with sand and chemicals known as “frac fluids” at high pressures. This high-pressure injection breaks up the shale, releasing natural gas which can then be recovered. At most wells, however, a significant fraction of the injected water returns to the surface as “flowback” or “produced water.” Some industry data suggests that up to one million gallons of flowback may be produced from a well in the month following fracturing.
Produced water generally contains not only sand and frac fluids, but also other contaminants, including metals, organic pollutants such as benzene, naturally occurring radioactive material (“NORM”) such as radium, and very high levels of dissolved salts like chlorine and bromine. In fact, produced water is often several times saltier than sea water.
Existing regulations already prohibit direct discharges of wastewater from shale gas extraction to surface waters. Some produced water is re-used to fracture additional wells, and a significant portion is disposed of deep underground in brine injection wells. Some produced water, however, is discharged to sewage treatment plants, which are generally ill-equipped to treat water as salty as shale gas wastewaters. Discharge of shale gas wastewaters to treatment plants has raised concerns that contaminants could pass through those plants without being effectively treated or interfere with the operation of the plants. EPA’s existing pretreatment regulations already include a general prohibition on discharges to sewage treatment plants that would either pass through or interfere with such plants; however, sewage treatment plants do not typically test their discharges for organic pollutants, NORM, or salts, making it difficult to determine whether they are effectively treating fracking contaminants before discharging them to rivers and streams.
In response to these concerns, EPA is considering proposing regulations requiring that shale gas wastewaters undergo some form of pretreatment before being discharged to sewage treatment plants. EPA is now gathering data on shale gas extraction wastewater, and expects to propose a regulation in 2014. Additional details on this proposal can be found in EPA’s 2010 Effluent Guidelines Program Plan, which was published in the Federal Register on October 26, 2011. Comments on the plan are due on or before November 25, 2011.
New York has also proposed its own pretreatment regulations for shale gas wastewater. These regulations would require sewage treatment plants to show that they are capable of removing contaminants expected to be present in flowback – including organic pollutants, NORM, and salts – before accepting any shale gas wastewater. Comments on these and otherNew York fracking regulations, are due before 5 p.m. on December 12, 2011.