If you follow environmental issues, or watched the 2012 Hollywood movie Promised Land, then you’ve probably heard of fracking. This term usually refers to a combination of two different technologies to extract natural gas from shale rock. (The technologies are horizontal drilling and high-volume horizontal multi-stage hydraulic fracturing; here’s a useful video. It took many years to develop this technique and you can read more about its history here (.pdf).)
Even though there are benefits from accessing more natural gas, some fear this technique contaminates groundwater or contributes to global warming. These issues are hotly debated – for a variety of different perspectives, see here, here, and here.
Regardless of one’s view of fracking for shale gas, there is one indisputable dilemma: what should we do with the wastewater it generates?
Traditional conventional wells are relatively shallow, vertical, and designed to target easily accessible pockets of gas trapped underground. Wastewater from these wells is usually deposited into deep underground formations.
In contrast, shale gas wells are deeper and use horizontal drilling to create long L-shaped wells that target natural gas trapped within tiny pore spaces of rock. Shale gas extraction can take place in areas without underground storage (.pdf), meaning industry must transport wastewater away from the well to other sites, manage it through reuse programs, or send the waste to a suitable treatment facility.
Of course, moving large volumes of this wastewater and injecting it underground may not be ideal for logistical reasons, and also because injection of wastewater into some of these wells has been linked to earthquakes. Wastewater reuse programs, while very common, offer just a temporary solution for long-term management because they work only as long as there is a net demand. So as an area matures and fracking declines, water reuse options likewise decline. Finally, even though treating wastewater is an option, our current wastewater treatment technologies are constrained by economics and overall performance. Industry must ensure the chosen treatment facility is appropriate for a specific wastewater stream, especially since components of flowback and produced water can vary so much by region and contain very-difficult-to-treat contaminants, like radium.
Unfortunately, recent history south of the border provides examples of mismatched treatment technologies for shale gas wastewater. In the early stages of Marcellus development in Pennsylvania, municipal wastewater treatment plants were used to process shale gas wastewater. These plants weren’t designed for this and they released harmful contaminants into the environment; see here and here (.pdf) for more information. Similarly, there have been cases where brine treatment plants, which were designed to handle wastewater from conventional oil and gas operations, were unsuccessful in treating fracking wastewater. These facilities were fined for failure to meet regulatory standards. Other technologies are out there – reverse osmosis or thermal distillation and crystallization – but these are expensive and require a lot of energy to treat the contaminated wastewater.
The search for appropriate wastewater management strategies is likely to increase if opportunities for underground storage or water reuse diminish. Now is the time to work on these issues in order to avoid an adverse environmental legacy.
Ontario does not currently have shale gas wells. Some of our geology is similar to areas producing shale gas, so this topic is considered an emerging issue in this province. Further details are in my 2010/2011 and 2012/2013 annual reports. Given these issues and the pending prospect of fracking in Ontario, two individuals used the Environmental Bill of Rights to request that the government develop regulations to address the potential adverse effects of fracking, including the management of fracking wastewater. In January 2013, the Ministry of Natural Resources and Forestry and the Ministry of the Environment and Climate Change agreed to undertake a joint review of this issue. I eagerly await the ministries’ response.
More information on hydraulic fracturing for conventional natural gas in Ontario is available in the Ontario Petroleum Institute’s report Safely Harvesting Energy – An Overview of Hydraulic Fracturing in Ontario (.pdf).