By Teresa Smith, Postmedia News, August 6, 2012
A new scientific study of the risks associated with Hydraulic fracturing — or “fracking” — in the United States, found that current methods for wastewater disposal put drinking water at risk.
Fracking involves pumping a mixture of water, sand and other chemicals deep underground at high pressure to fracture rocks, allowing the trapped natural gas to flow and then be pumped to the surface.
While resource companies have used technology in Canada and the U.S. on a small scale for decades, it’s expected to ramp up significantly in B.C., Alberta, Quebec and New Brunswick, as deep shale gas reserves are tapped in an effort to exploit natural gas deposits and diversify Canada’s energy resources.
But, in an American paper entitled “Water Pollution Risk Associated with Natural Gas Extraction from the Marcellus Shale,” the authors found that the process is likely to contaminate nearby water systems. The Marcellus Shale, the largest in the U.S., covers approximately 124,000 km from New York to West Virginia.
The paper, which appears in the August 2012 issue of the international journal Risk Analysis, says “even in a best case scenario, an individual well would potentially release at least 200 m3 of contaminated fluids.” Doctoral student Daniel Rozell and Dr. Sheldon Reaven, a professor in the Department of Technology and Society at Stony Brook University’s School of Marine and Atmospheric Sciences, partnered on the work.
In order to identify where regulators should focus their efforts, the study model identified five ways fracking could contaminate water supplies: transportation spills, well casing leaks, leaks through fractured rock, drilling site discharge, and wastewater disposal.
The authors found that the highest potential contamination risk was from wastewater disposal because, according to the authors, while some well operators recycle and reuse hydraulic fracturing fluids for multiple wells, 77 per cent of operators do not due to the cost of separation and filtration. “Instead, the used hydraulic fracturing fluid is transported to a wastewater treatment facility and discharged to streams” which can link up with drinking water, they wrote.
However, Professor Danny Reible, Chair of Environmental Health Engineering at the University of Texas, said the study’s projections are based on a large number of assumptions and it’s unclear how accurate or current the results could be.
Reible told Postmedia News Monday that the water in the Marcellus Shale already has among the highest salt content in the entire country, which could be why traditional wastewater treatment facilities had a hard time breaking it down.
Reible said most of the rest of the fracking sites in the U.S. dispose of their wastewater by re-injecting it deep into the earth at many separate sites, to avoid triggering micro-earthquakes. “That’s true of everywhere, except in the northeast of the U.S.,” he said.
Reible, who calls himself a supporter of fracking, “but not a blind supporter” says “I fully recognize that there are potential issues . . . I’ve made presentations in the past that showed that natural gas contamination in drinking water supplies has occurred” – due to natural migration of gas into the water table, as well as failures in conventional natural gas wells. “It’s something that you have to manage and be careful of.”
The Marcellus Shale study recommended that more data should be collected on the ability of industrial and municipal wastewater treatment facilities to remove contaminants from used hydraulic fracturing fluid, which can contain up to 750 distinct chemicals, ranging from benign to toxic.
“Given typical well spacing in the Marcellus Shale, if only 10 per cent of the region is developed, this would equate to 40,000 wells,” says the study.
“This volume of contaminated water would equate to several hours flow of (New York’s) Hudson River or a few thousand Olympic-sized swimming pools.”
In Canada, as shale gas exploration increases in B.C., Alberta, Quebec and New Brunswick, protests against fracking are also escalating, with protestors citing studies such as this one, which link the practice with contaminated water, and others which posit the practice can trigger small earthquakes.
Earlier this year, Quebec announced an outright moratorium on shale gas development, halting all projects until after a government environmental assessment committee looking into whether shale gas can be extracted while respecting the environment is finished. The final report is expected sometime in 2013.