**4.1. Microfiltration (MF)**

Microfiltration is a pressure driven process where separated compounds are 0.1–0.2 μm such as nanoparticles [33, 34]. It is regarded as the first pre-treatment of NF and RO membrane processes. MF removes little or no organic matter; however, when pre-treatment is applied, increased removal of organic material can occur. MF can be used as a pre-treatment to RO or NF to reduce fouling potential [35]. The main disadvantages of MF is that it cannot eliminate contaminants (dissolved solids) that are <1 mm in size. In addition, MF is not an absolute barrier to viruses. However, when used in combination with disinfection, MF appears to control these microorganisms in water [35].
