Pennsylvania to regulate salt dischargesThe Pennsylvania Department ofEnvironmental Protection (PADEP) is working to regulate saltdischarges that result from natu-ral-gas drilling. The move is a re-sponse to a statewide increase indrilling and to water pollution inthe fall of 2008 that affected a 70-mile stretch of theMonongahela River, thedrinking-water source formore than 300,000 peopleliving near Pittsburgh.High levels of total dis-solved solids (TDS), in-cluding chloride andsulfate, threaten manyother Pennsylvania water-ways, according to PADEP. But many gas andbusiness interests say theproposal is a poorly tar-geted overreaction.

Pennsylvania is at theheart of the latest natural-gas boom. In 2008, the stateissued permits for more than500 deep natural-gas wells,and drilling companies are leasingmineral rights for hundreds more.The Marcellus Shale, which liesabout one mile underneath most ofPennsylvania and parts of New York,West Virginia, and Ohio, is estimatedto be the third-largest natural-gasfield in the world, according to ge-ologist Terry Engelder of Pennsylva-nia State University. That gargantuanresource could provide enough natu-ral gas to ease the transition awayfrom fossil fuels and make the U.S.competitive with Russia as a natural-gas supplier.

To reach the gas, a deep produc-tion well that branches out horizon-tally must be drilled, and then overone million gallons of water, plusadditives and sand, are injected athigh pressure to fracture the rock(Environ. Sci. Technol. 2008, 10.1021/es802190h). The water pumped outof the well carries the additives andbrines that were trapped in the for-mation, along with low levels of met-als, sulfides, and radioactivity. As

production ramps up, millions ofgallons of water will need to betreated each day.

Too much chloride makes watertaste bad, damages cooling equip-ment and water heaters, and impactsaquatic life. But table salt and othersalts dissolve so easily and com-

pletely into water that they are diffi-cult and expensive to remove.Current methods are limited to re-verse osmosis, membrane filtration,and evaporation. In addition, mostwater treatment facilities are notequipped to treat drilling wastewater,which can contain up to 20%chloride.

Pennsylvania’s legacy of coal min-ing exacerbates the situation: drain-age from abandoned mines has leftmany rivers with relatively high levelsof sulfate. During last fall’s drought,TDS levelssmainly sulfate, but withsome chlorideson the MonongahelaRiver reached 900 parts per million,almost twice as high as the U.S. En-vironmental Protection Agency (EPA)standard, according to Teresa Can-dori of PA DEP.

At the same time, levels of bromi-nated disinfection byproducts (BrDBPs) increased in some systems. BrDBPs, which pose a greater healthrisk than chlorinated DBPs, made upmore than 90% of the byproducts

detected in some finished drinkingwater during the drought. “The highBr DBPs were associated with thehigh TDS. The bromide in the waterwasn’t measured, and we don’tknow the source,“ says water engi-neer Jeanne VanBriesen at CarnegieMellon University. “It’s likely thatdrilling is the source, because theMarcellus Shale is a marine forma-tion with high chloride and bromide,

and bromide is low in aban-doned-mine drainage. Butwe need to do the research.”

In April, PA DEP released“Permitting Strategy for HighTotal Dissolved Solids (TDS)Wastewater Discharges”,which proposes standardsfor pipe-end discharges of500 milligrams per liter forTDS and 250 milligrams perliter each for chlorides andsulfates. These figures comefrom EPA’s secondary stan-dards for drinking water.

“DEP doesn’t realize howmany businesses will be af-fected by these limits,” saysenvironmental lawyer JoelBolstein. “They need to find

a way to target Marcellus activitieswithout deterring economic growth.”In contrast, the Delaware River haslooser TDS standards; even so, thoselimits impact pharmaceutical manu-facturers, power plants, landfillleachate, and some wastewater treat-ment plants, according to DelawareRiver Basin Commission engineerChad Pindar.

Paul Hart, president of Pennsylva-nia Brine Treatment, Inc., a com-pany that treats drilling wastewater,opposes the proposed strategy, call-ing it an overreaction. For theMonongahela River, “the majority ofthe problem was sulfates, which arenot significant in oil and gas waste-waters,” he says. “Industry recog-nizes that salt will have to beremoved from some of the waterthat is disposed, but figuring outhow to do it will take several years.”

—REBECCA RENNER

Water impoundment in western Pennsylvania near theMonongahela River, where brine disposal has been linked toelevated levels of DBPs in drinking water.

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6120 9 ENVIRONMENTAL SCIENCE & TECHNOLOGY / August 15, 2009 10.1021/es901934m 2009 American Chemical SocietyPublished on Web 07/08/2009