Ultrafiltration (UF) is a membrane-based water treatment process used to remove suspended solids, colloidal particles, bacteria, viruses, and macromolecules from water. It operates on the principle of size exclusion, where a semi-permeable membrane with pore sizes typically ranging from 0.01 to 0.1 microns acts as a physical barrier to separate particles based on their size.

In ultrafiltration, water is passed through the membrane under pressure, forcing water molecules and smaller dissolved solutes to pass through while retaining larger particles and contaminants. This process effectively removes turbidity, suspended solids, pathogens, and other impurities from the water, producing clear and clean water suitable for various applications.