Fouling mitigation in produced water treatment by conjugation of advanced oxidation process and microfiltration.

Abstract

This work explored the use of ozonation and photoperoxidation before the microfiltration process to reduce fouling. Produced water was synthesized with salt, viscosifier, and surfactant. The additives influence on membrane fouling was evaluated. Photoperoxidation process led to an overall better performance than ozonation in terms of oil removal and fouling reduction. The maximum oil removal efficiency was 86%, obtained for emulsions with salt after 2h of treatment (COD: H2O2 ratio 1:1, UV dose of 965J/m2). The inclusion of chemical additives impaired the oxidative power of hydroxyl radicals leading to a moderate oil removal; however, they were still able to reduce membrane fouling, mainly in oil/water emulsions with viscosifier. Higher salt concentration promoted fouling resistance and also benefited the permeate quality. Cross-flow microfiltration process integrated with photoperoxidation was able to improve the permeate flux from 84 to 182L/m2.h after 3h of exposure to UV radiation, resulting in a permeate with less than 10mg/L of oil content. Graphical abstract.