Marcellus Shale drillers recycling more wastewater

Associated Press

PITTSBURGH

Pennsylvania’s Marcellus Shale gas-drilling companies are recycling more and more of their briny, chemical-laden wastewater, in most cases complying with a request from state officials to keep the pollutants from being discharged into rivers that supply drinking water.

But experts are wondering if a loophole in disposal regulations is still allowing significant quantities of one of the worrisome compounds— salty bromides— into rivers and streams, or if shale-gas drillers were only part of the problem.

The new mystery is this: Why hasn’t the dramatic progress on the wastewater recycling led to equally clear declines in river bromide levels?

An analysis by The Associated Press of 2011 state data released Friday found that of the 10.1 million barrels of shale wastewater generated in the last half of 2011, about 97 percent was either recycled, sent to deep-injection wells or sent to a treatment plant that doesn’t discharge into waterways.

Some of the new disposal trends also are raising other questions. The amount of Marcellus drilling waste injected deep underground nearly tripled in the last six months of 2011, with much of that going to Ohio.

In the same period of 2010, shale drillers sent about 2.8 million barrels of waste — or 118 million gallons — to numerous treatment plants that discharge into rivers and streams.

Those discharges raised alarms when the plants reported soaring levels of bromides in rivers that year. Though not considered a pollutant by themselves, the bromides combine with the chlorine used in water treatment to produce trihalomethanes, which can cause cancer if ingested over a long period of time.

Part of the answer to the mystery may be that the highly publicized plan for voluntary compliance by Marcellus drillers had a little-noticed loophole: it didn’t apply to thousands of other oil and gas wells in the state.