Special Issue on Environmental Impacts of Shale Gas Development

Shale oil and gas holds great promise as a newly accessible domestic source of energy. Shale gas is expected to grow from 23% of total U.S. dry gas production (in 2010) to more than 49% in 2035 [U.S. Energy Information Administration (U.S. EIA) 2012]. Many shale gas basins in the United States have great potential, including the Fayetteville in Arkansas, the Haynesville in Louisiana and Texas, and the Marcellus in Pennsylvania and West Virginia. Similarly, shale oil basins including the Bakken (North Dakota) and the Eagle Ford (Texas) will contribute to the U.S. oil supply over the coming decades. The potential economic benefits are significant, with estimates of $5.1 trillion in capital expenditures related to the industry between 2012 and 2035 (IHS Global Insight 2012). Engineering and technological development has paved the way for this shale energy transformation through the use of directional drilling and high volume hydraulic fracturing. Similarly, research into the potential adverse impacts of shale development has increased significantly over the past few years. Research has focused on impacts on water (Vidic et al. 2013; Olmstead et al. 2013), air (Pacsi et al. 2013; Roy et al. 2014), human health (Korfmacher et al. 2013; Finkel and Law 2011), and ecology (Entrekin et al. 2011; Drohan et al. 2012).

This special issue includes six papers covering important aspects of environmental issues associated with shale development.

Geng et al. present results of simulation of migration of pressurized air during drilling of a well. They report that compressed air is capable of creating a high-pressure gradient in groundwater at hundreds of meters from the drill hole in a confined aquifer. Their work suggests observational wells placed prior to drilling could alert drillers to pressure buildup.

Gilmore et al. evaluated the potential effect of water and wastewater truck transport associated with development of Marcellus shale gas. Their work highlights the importance of including all truck trips (including empty returns) when evaluating impacts and also suggests policy changes that could reduce impacts by improving planning.

He et al. considered the formation of barium and strontium sulfate in produced water from Marcellus shale development. Formation of precipitates can interfere with reuse of produced water, and equilibrium predictions are not always reliable due to the presence of organic matter.

Mauter and Palmer describe an expert elicitation related to current practices and future trends in wastewater management, focused on the Marcellus shale gas formation in Pennsylvania. Their work concludes that long-term water reuse is a viable strategy for management of produced water from shale development for companies with ongoing activity.

Strong et al. evaluated the biodegradability of produced water from shale development in the Marcellus and Bakken regions. A wide range of organic compounds were found, as were many halophilic bacterial species capable of biodegradation of these organics.

Wilson et al. consider shale-produced waters in comparison with other fossil fuel wastewaters to develop an anion ratio-based source identification method. Applying this method to data collected in Pennsylvania allowed identification of sources of changes in surface water quality.

We would like to thank the ASCE Journal of Environmental Engineering Special Issues Editor, Dionysios D. Dionysiou, and the ASCE publishing office personnel for their support during the development of this special section. Further, we are grateful to the important contributions of the reviewers during this process.