Ultrafiltration (UF) is a type of membrane filtration in which hydrostatic pressure forces a liquid against a semipermeable membrane. Suspended solids and solutes of high molecular weight are retained, while water and low molecular weight solutes pass through the membrane.
When strategically combined with other purification technologies in a complete water system, UF is ideal for the removal of colloids, proteins, bacteria, pyrogens and macromolecules from water. The primary removal mechanism is size exclusion, though surface chemistry of the particles or the membrane may affect the purification efficiency.
The primary advantages of low-pressure UF membrane processes compared with conventional clarification and disinfection (post chlorination) processes are:
- No need for chemicals (coagulants, flocculants, disinfectants, pH adjustment)
- Size-exclusion filtration as opposed to media depth filtration
- Since the basic principal of hollow fiber is filtration, it does not create any waste during operation except the undesired component in the feed stream
- Provides cost reduction in waste management
- Low energy consumption
- Good and constant quality of the treated water in terms of particle and microbial removal
- Process and plant compactness
- Simple automation
Ultrafiltration is used in
- Laboratory grade water purification
- Wastewater treatment
- Drinking water treatment
- Paint recovery in the automotive industry
- Fruit juice, wine and beverage industries
- Pretreatment for reverse osmosis
- Desalting and solvent-exchange of proteins
- Dialysis and other blood treatments
