Fracking Wastewater Could Encourage Formation Of Toxic Compounds During Drinking Water Disinfection | Chemical & Engineering News
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Web Date: September 23, 2014

Fracking Wastewater Could Encourage Formation Of Toxic Compounds During Drinking Water Disinfection

Environmental Chemistry: Laboratory experiments suggest that bromide and iodide in wastewater may contribute to formation of halogenated disinfection by-products
Department: Science & Technology
News Channels: Environmental SCENE, Analytical SCENE
Keywords: hydraulic fracturing, fracking, wastewater, drinking water treatment, disinfection by-products, bromide, iodide
High concentrations of halides in wastewater from hydraulic fracturing (seen here in a holding pond) can lead to increased levels of toxic compounds produced during drinking water disinfection.
Credit: Mladen Antonov/AFP/Getty Images/Newscom
Photo of holding pond for hydraulically fractured gas well in Waynesburg, Pa.
High concentrations of halides in wastewater from hydraulic fracturing (seen here in a holding pond) can lead to increased levels of toxic compounds produced during drinking water disinfection.
Credit: Mladen Antonov/AFP/Getty Images/Newscom

Some natural gas extraction operations have sent the highly saline water left over from hydraulic fracturing, or fracking, to wastewater treatment plants for disposal. These plants then discharge their treated water into rivers that may feed drinking water plants downstream.

A new study finds a possible problem with this process: Even when made 10,000 times more dilute, fracking wastewater can increase levels of troubling compounds formed under conditions similar to those during drinking water disinfection (Environ. Sci. Technol. 2014, DOI: 10.102/es50281841). Halides in the wastewater lead to toxic disinfection by-products, some at levels that exceed allowed discharge limits for drinking water treatment plants, the researchers say.

Chlorine and chloramine used to disinfect water can react with organic matter to form compounds such as trihalomethanes and haloacetic acids. These disinfection by-products have been linked to cancer and nervous system problems, and some are regulated by the Environmental Protection Agency. In the presence of other halides such as bromide and iodide, the disinfectants can create by-products that are even more toxic than their chlorinated analogs. Wastewater generated during hydraulic fracturing can contain high concentrations of these halides, and they remain after the water goes through commercial or municipal wastewater treatment.

William A. Mitch of Stanford University and his colleagues wanted to know how wastewater from fracking might influence disinfection by-product formation at downstream drinking water treatment plants. The researchers obtained two samples of wastewater from hydraulic fracturing operations in the Marcellus Shale in Pennsylvania. To simulate the chemical composition of what a drinking water plant might take in, they diluted the wastewater with water from rivers downstream of the shale operations to get samples containing 0.01 to 0.1% wastewater by volume. Then the researchers treated the samples with chlorine, chloramine, or ozone, just like at a drinking water plant.

Using mass spectrometry, they measured levels of a range of disinfection by-products and compared them with levels in treated river water without any fracking waste. In chlorinated samples containing as little as 0.01% wastewater, concentrations of trihalomethanes and haloacetonitriles were higher than those in treated, unaltered river water. Samples containing 0.1% wastewater had 70 to 140% higher levels of trihalomethanes, and concentrations of some of those compounds exceeded EPA limits. In ozone-treated water samples, levels of bromate, a potential carcinogen, were also above regulatory limits. The researchers also noticed that the fracking wastewater led to increases in levels of brominated and iodinated disinfection by-products, which tend to be significantly more toxic than their chlorinated analogs.

In an actual drinking water plant, the organic precursors to these compounds may be removed prior to disinfection, so the regulated by-products might be found at lower levels, the researchers write in the paper. But in 2010, the Pittsburgh Water & Sewer Authority measured a significant increase in trihalomethanes in drinking water (J. Am. Water Works Assoc. 2013, DOI: 10.5942/jawwa.2013.105.0093). The agency traced the problem to elevated bromide levels in the source water, which might have come from industrial wastewater treatment plants handling fracking waste.

The Pennsylvania Department of Environmental Protection has started to discourage fracking operations from sending their wastewater to municipal treatment plants in the state. Some of that wastewater has been diverted to Ohio for underground injection instead, though this disposal method raises concerns about induced earthquakes.

One solution to the disinfection by-product problem could be treating wastewater to remove excess halides, says Michelle L. Hladik, of the U.S. Geological Survey in Sacramento, Calif. She says the current study is useful for future studies on levels of the by-products leaving drinking water plants because it shows the relationship between the formation of the chemicals and the amount of added fracking wastewater.

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Stephen Stevick (September 24, 2014 9:01 AM)
What is not noted in this article is that the waste from natural gas extraction disposed of in waste water treatment plants, like the myriad of pollutants dumped into our waste water treatment systems, exits those systems in either or both the discharged water sent down stream or in the sewage sludge which itself must be disposed of. A common practice is to dispose of the sludge by spreading it on our agricultural lands as fertilizer, ready to be reintroduced into our food chain and delivered to your kitchen in any of a variety of forms. No solace should be taken from a waste water treatment process that fully extracts pollutants from the liquid portion of sewage as long as the remaining extracted pollutants, sludge, is reintroduced into the environment, whether it be to our agricultural fields, forest lands, or any other venue that results in contamination or our natural environment and/or harm to human health.
KEVIN LEYS (September 24, 2014 11:44 AM)
Why can't they stop messing with our precious life saving drinking water, and leave things as natural as they were, before man came on the scene?
The vast majority of the public do not want profit making unnatural fracking that will leave water courses contaminated.
Are we living in the Orwellian world of corporate control over food and water, or in a decent world of safe drinking water and true democracy?
Steven Franckhauser (September 25, 2014 8:54 AM)
Candidly, the only way to leave things as they were before humans developed is to eliminate humans. THAT is not a solution under any reasonable approach and adds nothing to solving any real problems.

Hydraulic fracturing has allowed for harvesting energy resources in the lease environmentally intrusive way in the history of civilization. Obviously, it is not perfect: no human effort is.

It is time to focus on improving what we have before we foresake generations of people as guinea pigs in the grand return to zero human footprint status.

The harsh reality is that humans use energy. I am more persuaded by human bevahior when I see trash in the streets and counterintuitive points of view on pollution and actual conduct than I am by a Pollyanish wish to return to the stone age.
Al Barney (November 11, 2014 9:37 AM)
Why not solar and wind power!
Bill Green (November 11, 2014 10:04 AM)
We have wastewater treatment method that takes all the pollutants out to discharge limits but the gas drilling operators have not yet begun to employ the co-precipitation method. Maybe because its patented and they don't want to pay for the development costs. Their treatment plan is to use holding ponds and let the solids settle and decant off the cleaner water. Unfortunately many pollutants and salts referred to in the article remain in ion form. Co-precipitation process will release most of those ions of various pollutants and produce safer water.
Jeffrey Bailey (September 17, 2015 1:01 AM)
A fracking wastewater treatment plant has been approved for Doddridge County, WV, with construction already under way. Antero Resources, will be the owners and operators of the plant. Despite the fact that in 2012, then Governer Manchin ordered a prohibition of returning any wastewater product, treated or otherwise, or water produce to the land in any form. Currently, "brine" (a very soft euphemism for all sorts of toxic ingredients plus saltwater) can be legally used as a road de-icer during winter storms, but Manchin's order is still in effect for all of West Virginia, according to the West Virginia Department of Evironmental Protection, despite the fact that Manchin's term as Governor has passed. Antero claims that newer, more advanced technologies can remove radioactive ingredients such as radium 226, as well as chlorides, bromides (halogens), and heavy metals. An engineering representative from Antero informed many of us during a County Council meeting that salts resulting from their wastewater treatment could be sold to anyone on the market, including the West Virginia Department of Highways, for use in treating roadways during winter storms, completely ignoring former Governor Manchin's mandate.

When asked about what would be done with the resulting sludge after wastewater treatment, which contains radium 226, chloride, bromide, and heavy metals, the Antero representative responded that it would go to a landfill to be named at a later date, possibly constructing their own landfill. Pennsylvania boasts of being the only state with radioactivity alarms at all their landfills. To my knowledge, West Virginia has no landfills with radioactivity detectors, and if Antero is granted a permit to construct their own landfill, who is to regulate it? When it comes to the fracking industry and this latest boom, lots of industry related organizations have been coming up dirty. In Pennsylvania, a company recently plead guilty to falsifying over 3000 water test results. When enormous amounts of money are involved, as is the case with fracking, it is virtually impossible to know who to trust. Those of us who are personally affected by nearby well pads, water trucks, pipelines, wastewater treatment plants, landfills, etc, will be merely natural gas cannon fodder. Collateral damage. Acceptable victims.

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