The oil and gas industry’s view of water production, once regarded primarily as a waste stream, has shifted in recent years due to the growing environmental and economic challenges. Industries now recognize the substantial volumes of water produced during production operations and are actively exploring alternative water management strategies. Among these, water treatment stands out as a leading approach, aimed at purifying the water to achieve specific element concentrations suited for targeted applications. The produced water from oil and gas reservoirs is a complex mixture of various organic and inorganic compounds, as well as dissolved and suspended solids. It is considered a highly contaminated waste stream, making effective treatment essential to meet future critical water demand. The physical and chemical properties of the produced water vary depending on the extraction location, geological formations, and type of hydrocarbon produced. This review examines multiple treatment methods used for the beneficial reuse of produced water, covering physical, chemical, and biological techniques, along with examples demonstrating their effectiveness in field case studies.

This study evaluates the feasibility of repurposing produced water—an abundant byproduct of hydrocarbon extraction—for green hydrogen production in Wyoming, USA. Analysis of geospatial distribution and production volumes reveals that there are over 1 billion barrels of produced water annually from key basins, with a general total of dissolved solids (TDS) ranging from 35,000 to 150,000 ppm, though Wyoming’s sources are often at the lower end of this spectrum. Optimal locations for hydrogen production hubs have been identified, particularly in high-yield areas like the Powder River Basin, where the top 2% of fields contribute over 80% of the state’s produced water. Detailed water-quality analysis indicates that virtually all of the examined sources exceed direct electrolyzer feed requirements (e.g., <2000 ppm TDS, 10% LCOH) are notable, electricity pricing (50–70% LCOH) and electrolyzer CAPEX (20–40% LCOH) are dominant cost factors. While leveraging produced water could reduce freshwater consumption and enhance hydrogen production sustainability, further research is required to optimize treatment processes and assess economic viability under real-world conditions. This study emphasizes the need for integrated approaches combining water treatment, renewable energy, and policy incentives to advance a circular economy model for hydrogen production.