A Modeling Framework for Technical, Economic, Energetic, and Environmental Assessment of Produced Water Pretreatment from Oil and Gas Industry: Article No. 117026

Treatment and reuse of produced water (PW) generated from oil and gas industry can reduce PW disposal volume and costs, improve environmental sustainability, and offset freshwater uses. Due to the complexity and high scaling and fouling propensity of PW, PW pretreatment is essential to ensure the long-term operation of downstream desalination processes. This study developed a process modeling approach to evaluate pretreatment technologies through technical, economic, energetic, and environmental assessments to identify the impacts of each technology, such as costs, energy consumption, and carbon dioxide emissions, to make informed decisions for integrated treatment train development and applications. The evaluated individual and combined PW pretreatment technologies included chemical softening (CS), chemical coagulation (CC), electrocoagulation (EC), and granular activated carbon (GAC) for removing key fouling and scaling constituents, such as hardness, silica, and organics. The main evaluation parameters include levelized cost of water ($/m3), cumulative energy demand (kWh/m3), specific energy consumption (kWh/m3), and carbon dioxide emissions (kg CO2-eq/m3). The case study evaluated the unconventional PW in the Permian Basin with total dissolved solids concentration of 130,000 mg/L. For pretreatment combinations, the implementation of EC+GAC was selected as the optimal choice due to its effectiveness and limiting the amount of waste for disposal. This study provided a modeling framework for optimization and integration of different pretreatment units accounting for three evaluation metrics (costs, energy, and CO2 emissions) to effectively evaluate their viability in PW applications centered on minimal- or zero-liquid discharge.