Microfiltration and ultrafiltration belong to the membrane filter technologies. They are physical separation techniques which work according to the screening method. Classification is made to the size of the particles. The ones which are larger than the pores stay on the membrane. The driving force is pressure difference between feeding and filtrate site.
Microfiltration and Ultrafiltration are used to remove insoluble and colloid particles from the water and can be used as well for removing of oil droplets from water. It is not possible to remove dissolved materials from liquids.
Concerning the separation range, which means the size of the particle or rather the molecule they close the gap between reverse osmosis and nanofiltration on one site and filtration on the other site.