Rising populations, regional droughts, and declining groundwater levels are among the many factors driving freshwater stress in the United States. According to a new report released by the Groundwater Protection Council (CWPC), produced water may become a resource that reduces the use of fresh water in specific locations.
“We are concerned about the overuse of fresh groundwater resources, and we wanted to explore how produced water might help fill that gap,” GWPC Executive Director Mike Paque said in a statement. “By identifying opportunities and challenges of using produced water and offering options for addressing them, we hope to facilitate the development of produced water as a supplement to freshwater resources.”
The report addressed the drivers and potential benefits for increasing produced-water reuse in unconventional oil and gas operations and outside the industry, as well as the economic, scientific, regulatory, and policy considerations, particularly with respect to risk management. It said that the opportunities for increased produced-water reuse will vary greatly depending on local conditions, including the quality and quantity of produced water available; the profile of regional water supply and demand; and the existence of infrastructure for moving, storing, and treating the water.
States have various statutes and regulations for water planning, but only three of the six states reviewed for the report (Oklahoma, Kansas, and California) include produced water as a component in their state water plans. The report speculated that this may be because produced water has not traditionally been considered a potential source of water. However, as treatment technology advances, populations grow, and water scarcity becomes more pronounced, the view of produced water may change over time.
Water management and reuse programs are also evolving in most regions, as operators deal with increasing volumes and public concern over induced seismicity. The report cited efforts such as Pioneer’s pipeline network, which will run through several counties in the Midland Basin once completed; Antero’s desalination plant in West Virginia, which, at 60,000 BWPD capacity, is the largest plant designed for produced-water reuse; and Anadarko’s closed-loop water-on-demand system in Colorado that consists of more than 150 miles of pipeline. Most mid- and large-sized producers are aiming to reduce freshwater sourcing.
The report said that produced-water treatment and reuse may provide opportunities for other industries to reduce freshwater consumption, but there are significant considerations they must take into account in ensuring that a change in water source does not negatively affect their industrial outcome, including:
- Process implications because of a change in the character of source water, such as scale deposits
- Modifications in the character and required management of disposal of residual wastes
- The need for additional pretreatment before use
- Worker safety and exposure considerations for handling new water sources
There have been several proposed strategies for maximizing produced water’s value as a water source, though most studies on this have indicated that produced water would require high, likely cost-prohibitive, levels of treatment to meet reuse objectives outside of oil and gas. As treatment and remediation procedures continue to improve the quality of produced-water streams, concerns of associated toxicity may go down as well.