Resource Recovery and Beneficial Reuse of Produced Water in Energy Operations, a Review of Sustainable Pathways

Produced water (PW), the largest by-product of oil and gas operations, presents both environmental challenges and opportunities for resource recovery and beneficial reuse. Traditionally considered a waste stream, PW contains valuable constituents, including nutrients (nitrogen and phosphorus), organic matter, salts, and minerals, which can be harnessed to support circular water management and sustainable energy operations. This critically evaluates the emerging pathways for resource recovery and reuse of PW, emphasizing the integration of physicochemical and bio-based treatment strategies, digital monitoring, and modular or decentralized system designs. The chemical and physical characteristics of PW such as high salinity, total dissolved solids (TDS), hydrocarbons, heavy metals, naturally occurring radioactive materials (NORM), and nutrient content determine the feasibility and selection of recovery and reuse technologies. Nutrient recovery through biofilm reactors, algal consortia, and other biological systems enables the production of biofertilizers or soil amendments, while biomass harvesting allows conversion of organic matter into energy or value-added products. Salt and mineral extraction using crystallization, evaporation, and adsorption technologies provides additional economic opportunities and reduces environmental disposal impacts. Beneficial water reuse options include irrigation for non-food crops, industrial process water, and enhanced oil recovery (EOR), contingent on achieving effluent quality compatible with specific applications. AI-driven monitoring and optimization facilitate adaptive process control, improving recovery efficiency, reducing energy and chemical usage, and ensuring consistent effluent quality. Modular and decentralized treatment systems enhance operational flexibility, particularly in remote or water-stressed environments, while aligning with circular water management principles. Despite advancements, research gaps remain, including long-term operational validation, standardization of treatment and reuse protocols, and integration with renewable energy systems. This review highlights the strategic value of resource recovery and water reuse from PW, offering sustainable pathways that reduce environmental impact, enhance operational efficiency, and transform PW from a waste liability into a valuable resource. Future work should focus on scalable, field-validated solutions that integrate advanced treatment, monitoring, and resource recovery technologies to enable resilient and sustainable PW management.