A pair of water advocacy groups claim that two Pittsburgh-area treatment plants have been discharging oil and gas wastewater without proper permits.

Clean Water Action and Three Rivers Waterkeeper sent letters Thursday to the Franklin Township Sewer Authority and the Municipal Authority of the City of McKeesport, saying they planned to sue both utilities for discharging Marcellus Shale wastewater into the Monongahela River watershed.

The groups said the two sewer authorities discharge up to 150,000 gallons of Marcellus Shale wastewater per day into the Monongahela and its tributaries. The Monongahela supplies drinking water to half a million people, including the city of Pittsburgh.

The letters are the first step in a “citizens suit,” a process in the federal Clean Water Act that allow citizens to sue to demand enforcement. The groups believe this is the first time that legal action has been filed to stop facilities in Pennsylvania from discharging Marcellus Shale wastewater. The letter provides 60-days notice of intent to sue, giving the two sides a chance to stave off a court battle by coming to some agreement first.

The groups claim that the two sewer authorities violated the Clean Water Act by discharging oil and gas wastewater without the proper permits. Representatives from the utilities told NGI’s Shale Daily they could not comment until they reviewed the claims made by the groups.

The claims stem from an October 2008 incident when low water flows on the Monongahela River and the burgeoning Marcellus Shale industry caused concentrations of total dissolved solids (TDS) and sulfates in the river to reach historic highs. The Pennsylvania Department of Environmental Protection (DEP) responded by ordering publicly owned treatment works to limit oil and gas wastewater to 1% of their average daily flow.

According to the groups, the DEP issued consent orders to both facilities allowing the discharging to continue.

“DEP’s consent orders are private deals that are negotiated without public input,” said Clean Water Action’s Myron Arnowitt. “The public is not notified and there are no public hearings as there would be if they applied for a Clean Water Act permit to discharge appropriately treated Marcellus wastewater.”

In 2010, Pennsylvania enacted stricter discharge standards for treatment plants, limiting gas wastewater discharges to 500 milligrams per liter of TDS. Clean Water Action said that rule grandfathered plants already discharging Marcellus Shale wastewater.

Pennsylvania could soon be re-examining discharge permits. The U.S. Environmental Protection Agency recently sent a letter to state officials saying that existing National Pollutant Discharge Elimination System (NPDES) permits don’t include provisions for treating wastewater from drilling operations and need to be updated. The NPDES is a federal program for controlling water pollution and is typically run by state governments (see Shale Daily, March 9).