New advancements, challenges, and future needs on treatment of oilfield produced water: A state-of-the-art review

Various stages of oil production and processing in petroleum industry produce an enormous amount of oilfield produced water (PW). Discharge of this huge amount of PW has an adverse impact on the surrounding environment as it contains different types of toxic and complex organic and inorganic compounds. For a long time, conventional treatment methods have been used to purify PW; however, these techniques could not meet the environmental regulations especially when the purpose is to reuse water. Therefore, more research efforts are required to select an effective technology that can mitigate the challenges through the best management strategy. In this study, the oilfield PW sources and characteristics, discharge regulations, treatment management, and recent advancements, challenges, and future needs in physical, chemical, thermal, biological, membrane, and hybrid treatment techniques are reviewed. Since the wastewater includes different recalcitrant pollutants, single technologies to date have not been successful enough in rendering it to a reusable form or meeting disposal requirements. Therefore, combined technologies might offer a promising process not only to meet the regulatory criteria but also to provide opportunities to use PW as a non-conventional water source. Furthermore, PW management needs a structured framework and a risk-based approach considering environmental, technical, and economic aspects to choose and design the most efficient strategy(ies).