Alternative Management of Oil and Gas Produced Water Requires More Research on Its Hazards and Risks

Abstract

Produced water is the largest waste stream associated with oil and gas exploration and production operations. Most produced water generated onshore is managed by permitted injection in deep underground wells, but alternative disposal options including reuse are increasingly being considered. However, insufficient understanding of the composition and toxicity of produced water imposes significant constraints on effective management of potential short‐term and long‐term risks associated with such alternative uses. As interest builds for management options, such as surface discharge, livestock watering, irrigation, and other industrial uses, research is needed to assess produced‐water hazards and exposures to both humans and the environment. This challenge affords an opportunity to capitalize on emerging risk assessment tools. Innovative and comprehensive approaches to filling data gaps and assessing produced water risks will be imperative. A group of experts from industry, academia, and government were assembled to define research needs to support objective decision making on the acceptability, or lack thereof, of produced water disposal alternatives. Presented here are key outcomes from that workshop and recommendations for a research framework to assess toxicity of produced water and associated risks from above ground discharge and reuse options. Integr Environ Assess Manag 2019;15:677–682. © 2019 SETAC.

Optimization of thin film solid phase microextraction and data deconvolution methods for accurate characterization of organic compounds in produced water

“…In spite of the hypersaline, oily and corrosive properties of PW, the HLB TF‐SPME device proved to be robust throughout many extractions, retaining its extraction efficiency throughout the entire study. In efforts to meet the goals outlined by various agencies [3,9,10], future efforts should focus on the coupling of comprehensive sampling techniques to more extensive instrumentation such as GC×GC hyphenated to high‐resolution MS, a strategy already being exploited for oil analysis [42] and a handful of PW reports [17,22]. While LC has been utilized for the analysis of PW [16,43], there is, however, no reports at this time for the analysis of PW using 2D LC hyphenated to MS.…”

“…It has been proposed by a variety of different sources, academic, industrial, and governmental, that the forefront of PW research should focus on the identification of toxicological risks that might be incurred as a result of the various reuse scenarios that have been proposed [3,9,10]. In light of these goals, a comprehensive understanding of the multitude of constituents in these matrices is critical to (1) better inform toxicological research and (2) scrutinize the eligibility of different PW reuse scenarios.…”

“…Being a mixture of shale oil, native brine, and chemical additives, there is a wide range of unknown compounds with different physicochemical properties. These properties in many cases disallow a single analytical method to properly analyze the entire range of analytes, the matrix itself being often corrosive and hypersaline, which, in turn, makes it challenging to introduce to analytical instrumentation without extensive sample preparation [9]. The majority of organic analysis on PW has been so far nonspecific, being driven by techniques such as total organic carbon (TOC) analysis and gravimetric analysis for both dissolved organic matter (DOM) and total suspended solids (TSS) [11].…”

Mutagenicity assessment downstream of oil and gas produced water discharges intended for agricultural beneficial reuse

“…Furthermore, a range of toxicological endpoints must be assayed including some, such as endocrine disruption, that remain to be analyzed at this site (Ohe et al, 2004). This could be achieved with a high-throughput assay that assesses a range of toxicological endpoints (Danforth et al, 2019). Many PW treatment studies have focused on a "treat for use" approach.…”

National Alliance for Water Innovation (NAWI) Agriculture Sector Technology Roadmap 2021

“…91 Once the oil is removed, some water is diverted for steam generation or lease water, but the majority is pumped to a series of reservoirs for blending and eventually discharge to the agricultural irrigation systems. 92 On the other hand, high-salinity PW, with TDS ranging from 10,000-400,000 mg/L, would require a much more intensive and expensive process focused exclusively on TDS removal to meet agricultural standards. Limited studies have addressed the long-term impact on soil health of using highly saline PW for irrigation.…”