Materials and Technologies for the Tertiary Treatment of Produced Water Contaminated by Oil Impurities through Nonfibrous Deep-Bed Media: A Review

This review covers various aspects of the treatment of emulsified oil/water mixtures and is particularly focused on tertiary treatment, which means the reduction of the oil content from 70-100 ppm to below 10 ppm, depending on national regulations for water discharge. Emulsified oil/water mixtures frequently occurs in water treatment processes because, in the petroleum industry, chemically enhanced oil recovery leads to the production of a vast amount of oil-emulsified wastewater. This review is focused on various aspects of tertiary treatment via granular deep-bed filtration. The importance of polymeric materials, as well as carbon nanostructures, which may be an alternative to the current media have been highlighting. The particular potential of polymers is based on their broad availability and low price (particularly for polyolefins), the simple treatment of their surfaces through a variety of chemical and physical methods to design surfaces with tailored surface free energy (wettability), and the porosity. Polymer technology offers a variety of well-established methods for designing foams with tailored porosity, which, together with appropriately tuned surface energy and controlled roughness, would open new avenues for the production of foamy media for efficient oil/water separation. Additionally, a crucial inventions in deep-bed filtration is discussed.