Large volumes of waste water are generated in the oil and gas industry, and projections show that these volumes will only increase. Currently, the majority of produced water is managed by disposing of it using a practice known as underground injection, where that water can no longer be accessed or used. The limits of injection are evident in some areas, and new approaches are becoming necessary. Some states and stakeholders are asking whether it makes sense to continue to waste this water, particularly in water-scarce areas of the country, and what steps would be necessary to treat and renew it for other purposes.
As a result, the US Environmental Protection Agency (EPA) conducted a study evaluating management of produced waters from onshore oil and gas extraction activities. The EPA wanted to better understand produced water generation, management, and disposal options at the regional, state, and local levels for both conventional and unconventional onshore oil and gas extraction.
While the EPA looked at a variety of alternatives for reuse of produced water, ultimately, the EPA’s study goal was to evaluate approaches to manage oil and gas extraction waste waters generated at onshore facilities, including but not limited to an assessment of technologies for facilities that treat and discharge oil and gas extraction waste waters to surface waters that are regulated under the Clean Water Act (CWA).
A second goal was to better understand any potential need for, and any concerns over, additional discharge options under the CWA for onshore oil and gas wastewater.
Representatives of state agencies that the EPA engaged for this study generally supported increasing opportunities for management of oil and gas waste waters including discharge of oil and gas extraction and production waste water. Reasons include providing additional flexibility for producers, opportunities to address water-scarcity concerns, and to provide additional water for agriculture. Representatives of some agencies raised concerns regarding the treatability of produced waters and the unknown human health and ecological risks that might occur.
Those who expressed concern raised issues about the unknown chemistry of produced waters and the effects on surface waters that have important cultural uses. Nationally, there is broad support among the oil and natural gas industry and its service providers for additional wastewater management options including to treat and discharge produced waters more broadly. However, support is not universal as some oil and natural gas companies are satisfied with the current regulatory structure and others perceive potential liability concerns associated with alternatives such as discharge.
Other NGOs (and associations of state regulators) see potential benefits related to water availability associated with increased opportunities for discharge of treated produced waters. In addition, some are supportive of additional discharge options, seeing opportunities to generate revenue from the treated produced water and to facilitate growth in oil and gas extraction.
Those in academia that the EPA engaged identified concerns related to the unknown chemistry of produced waters and the limited amount of data regarding treatability of produced waters. These concerns include the risk to human health or environmental implications of discharge. Some in academia stressed the need for additional research into these topics, noting that some studies are currently under way. Some also saw the potential for reducing the cost and improving the performance of treatment technologies that could make treatment for discharge more cost-competitive with other management options.
This report details the information obtained during the EPA’s outreach to stakeholders on these topics. The information in this report will help the EPA determine whether any future actions are appropriate to further address oil and gas extraction waste water.