Natural gas drilling in the Marcellus Shale not only places a huge demand on on local water supplies, but also generates large volumes of wastewater.
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This presentation was given at the 2010 PSATS Annual Conference at Hershey Lodge in Hershey, PA, April 18-21. We conducted this interview with Bryan A. Swistock, Water Resources Extension Specialist at Penn State after the conference.
Empowered: What are the most important issues with drilling for Marcellus Shale related to water quality?
Swistock: There are three key issues:
First, the flow of water to private water supplies can be interrupted or they can become contaminated. Methane gas migration can also enter the water supply during drilling or extraction. Because methane gas is a naturally occurring substance in Pennsylvania, this is not a new problem.
Second, surface water can be contaminated from spill, leaks or illegal dumping. These problems are more likely to occur at drilling sites near surface streams. Currently, legislation only requires a 100 foot setback from streams. As many of the locations for extraction are flat and near water, this 100 foot setback may not always be sufficient to protect surface streams and downstream users (like public water suppliers).
Third, use of wastewater by recycling and reuse is an on-going issue. Current regulations permit the recycling and reuse of wastewater. New regulations are making the treatment of wastewater more stringent. There are many unknowns about the issues related to recycling the wastewater.
Empowered: Is it true that gasses could be used to "frack" the shale instead of water?
Swistock: Yes, there is research ongoing to develop alternative methods of fracturing that do not require water. Fracturing using carbon dioxide, propane, and nitrogen have all been investigated. Each of these methods, while promising, have their own problems such as contamination of the methane gas.
Empowered: What are some of the technical solutions to meet these problems?
Swistock: Treating the wastewater in place can be done. There are existing technologies. Removing the salt from the water is possible, but is it expensive and the infrastructure is not in place. Building more, local treatment plants is an option, but most of the companies have stepped back from this because of the increased interest in recycling and reuse of wastewater. Because federal and state regulations are being altered, it is not clear how many new treatment plants or deep injection wells will be developed in the near future. Without having a clear useage defined, it is almost impossible to forecast revenue for new treatment plants. Until this is more clear, no one will be willing to make an investment. Partnerships between local government and companies to build and even own the treatment plants are an option also.
Empowered: What are some of the regulatory problems?
Swistock: Pennsylvania made an early decision to allow Marcellus drilling to occur while regulations were developed and altered. New York decided to do the opposite and stop drilling while regulations could be developed. Many Pennsylvania regulations have already been changed (permit fees, gas well construction, water management plans, etc.) while others are still being studied. The location of drilling in comparison to surface water is one regulation that is still in flux. The current setback between drilling and drinking water supplies of 200 feet is another regulation that should be investigated. Bonding is another issue. Currently, companies only have to have a bond of $2,500 to cover the cost of lost water supply to a local owner. This is generally not sufficient to cover the cost of re-drilling or treating a water supply.
Inspections can help to prevent problems such as erosion and sediment problems during initial site clearing and drilling Inspections can also help to limit the chance that the flow from a nearby drinking water supply is interrupted by gas well drilling.
A more serious issue is methane migration. Proper construction of the casings that protect the water supply from the gas and wastewater need to be inspected during and throughout the operation of a well. New regulations have increased the requirements on cementing of gas well casings in an attempt to prevent future methane gas migration problems.
The same goes for ponds, tanks and liners used to store wastewater. They need proper inspection during construction and throughout the life of their operation, to ensure they are not leaking. Inspections are also needed to ensure that pits are not used in areas where groundwater is too close to the surface or where nearby stream flooding may occur. To view the complete power point, click on the link below.
By: Bryan A. Swistock
