Fouling mitigation strategies for different foulants in membrane distillation

•Biofouling is not fully understood due to the lack of experimental data.•Specific mitigation method is suggested for each type of fouling.•Inorganic fouling can be avoided by pre-treatment methods. Providing clean water to a rapidly growing population is an issue that is currently getting lots of attention to offer a sustainable solution for water scarcity. Membrane distillation (MD) is one of the latest technologies that provides great potential in water treatment. Even though there is a tremendous amount of research done during the past two decades on membrane distillation, the long-term use of this process is still restricted by membrane fouling. Membrane Fouling can be defined as the accumulation of various materials in the pores or surface of the membrane that affect permeate's quantity and quality. This review highlights the recent observations on various foulants in MD process. Moreover, different fouling mechanisms of inorganic fouling, organic fouling, biological fouling, and colloidal fouling were investigated for better understanding and prevention of membrane fouling. In order to achieve a sustainable MD process, various techniques to mitigate fouling were discussed comprehensively including pre-treatment processes and cleaning methods. The benefits and disadvantages of these approaches have been investigated and reviewed in order to provide an overall understanding of fouling minimization in membrane distillation process. Fouling mitigation strategies have been suggested for different foulants in membrane distillation. [Display omitted]