Membnrane filtration is when Water under high pressure is forced through a membrane, a thin material with very small pores, stopping small particles (including bacteria). Source: GreenFacts. More: There are four categories of membrane filtration: reverse osmosis (RO), nanofiltration (NF), ultrafiltration (UF), and microfiltration (MF).
Membrane Technology. ... The membrane separation process is based on the presence of semi permeable membranes. The principle is quite simple: the membrane acts as a very specific filter that will let water flow through, while it catches suspended solids and other substances.
Membrane filter a filter made up of a thin film of collodion, cellulose acetate, or other material, available in a wide range of defined pore sizes, the smaller ones being capable of retaining all the known viruses.