Recent advances in oil/water emulsion separation

This chapter comprehensively addresses the critical environmental challenge of oily wastewater, focusing on its sources, composition, environmental impact, and advanced treatment technologies. The review highlights the urgency of treating oily wastewater, emphasizing its generation from a variety of industries such as petrochemical, heavy metal, food processing, paint, and automobile sectors. The detrimental effects of such wastewater on human health and the environment, including its mutagenic and carcinogenic properties and the disruption of aquatic ecosystems, are underscored. In addressing the treatment of oily wastewater, the chapter extensively discusses conventional technologies like dissolved air flotation, coagulation, and solvent extraction. It may be others, as well as their limitations in handling a wide range of emulsified oily wastewater compositions. In contrast, membrane filtration emerges as a more versatile and effective method, capable of treating oily wastewater with high oil removal efficiency. The review elaborates on various aspects of implementing membrane technology, including commercially available membranes, modules, operation modes, and hybrid systems. It also provides an economic analysis of these technologies. Furthermore, the chapter evaluates the regulatory frameworks that dictate the extent of treatment required before discharging wastewater into the environment. It then delves into the challenges associated with membrane filtration, such as membrane fouling, and discusses strategies to quantify and mitigate these issues. State-of-the-art techniques for monitoring and controlling membrane systems are briefly explored, offering perspectives on future developments in the field. In addition to membrane technology, other advanced oily wastewater treatment technology (bioremediation) is also examined by discussing the role of various microorganisms in bioremediation, both for large-scale oil spills and for treating oil-water emulsions at the source. The chapter concludes by highlighting operational processes from different oily wastewater treatment plants, offering a comparative view of the various treatment methods. This comprehensive analysis of oily wastewater treatment technologies underscores the importance of selecting appropriate methods based on the specific characteristics of the wastewater and the desired level of purification, thereby contributing significantly to environmental protection and sustainability.