Ultrafiltration (UF)

Applying pressure-driving purification to meet stringent water-quality standards.

 
 
 

Pressure-driven purification for clean water at a lower cost

Ultrafiltration (UF) is a pressure-driven purification process that separates particulate matter from soluble compounds using an ultrafine membrane media. Ultrafiltration is an excellent separation technology for desalination pretreatment, reverse osmosis pretreatment, and wastewater reclamation, as well as for producing potable water.

With over 70 years of separation-technology leadership and products in more than 1,000 ultrafiltration installations worldwide, we offer a portfolio of products designed for outstanding membrane separation, extreme productivity and efficiency, and exceptional reliability.

 
 
 
Ultrafiltration (UF) details

A closer look

See more details about ultrafiltration.
What Is UF?
UF Technology Basics
Hollow Fiber Technology

Superior to sand filters and traditional media filtration

As with most conventional filtration methods, sand filters and media filtration require consistent raw water quality to deliver quality effluent, which is not always possible. They also don't provide an absolute barrier. Traditional media filters typically remove particles to down to about 5 microns.

Ultrafiltration (UF), however, does not suffer from those limitations. This technology uses an ultrafiltration membrane barrier to exclude particles 0.02 to 0.05 microns, including bacteria, viruses, and colloids, meeting increasingly stringent water-quality standards around the world, and providing a stable, reliable, and consistent water quality.

UF offers:

  • High and consistent product quality measured by turbidity (NTU) or silt density index (SDI).
  • Tolerance to feedwater quality upsets.
  • No use of pretreatment chemicals (polymer, coagulant, pH adjustment) and associated costs for sludge disposal.
  • Small footprint and less weight than media filters.


When used as a pretreatment for reverse osmosis (RO) , UF also helps reduce fouling of the RO membranes, which can lead to:

  • Reduced chemical cleaning frequency and consequently, lower operating costs and downtime.
  • The potential to operate RO at higher flux, with fewer membranes and vessels — leading to lower capital cost for the RO system.

Rejecting particles, colloids, and macromolecules

In ultrafiltration, water and low-molecular-weight substances are passed through an ultrafine membrane by the application of pressure to the system; flow through the membrane is achieved by applying a pressure gradient between the outer and inner walls of the membrane structure. Feed pressure is from 4 to 100 psig (typically < 30) and transmembrane pressure is generally <14 psig.

Ultrafiltration membranes have pore sizes in the range of 0.02 – 0.05 microns, which contributes to the production of high-quality water; the pore-size range means that the purification process is characterized by a high removal capability of bacteria, viruses, colloids, and silt. The process, however, does not reject particles smaller than the pores, such as dissolved salts or organics; nor does it reject other species such as true color, taste, and odor.

Ultrafiltration membranes have a service life of three to seven years (and potentially longer). They are commercially available in hollow fiber, tubular, plate, and frame, as well as spiral wound configurations.

High-filtration performance, high recovery, and energy savings

Our ultrafiltration modules are made with high-strength, hollow-fiber ultrafiltration membranes that offer the following features:

  • 0.03 μm nominal pore diameter to facilitate high-removal capability for bacteria, viruses, and particulates, including colloids.
  • PVDF polymeric hollow fibers for high strength and chemical resistance.
  • Hydrophilic PVDF fibers for easy cleaning and wettability to help maintain long-term performance.
  • Outside-in flow configuration for high tolerance to feed solids and the use of air scour cleaning.
  • U-PVC housings, which eliminate the need for pressure vessels and are resistant to UV light.


The outside-in flow configuration is tolerant of wide-ranging feed water qualities and allows air scour cleaning. The dead-end flow offers higher recovery and energy savings. The pressurized vertical shell-and-tube design eliminates the need for separate pressure vessels and allows easy removal of air from cleaning along with integrity testing steps.

The hollow fiber ultrafiltration membranes are 1.3 mm outside diameter and 0.7 mm inside diameter and are made from PVDF polymer. The fibers are strong due to a combination of PVDF polymer, an asymmetric membrane with smaller pores in the active filtration area, and a high porosity substructure. PVDF membranes offer high chemical resistance (e.g., resistance to chlorine) and are tolerant to temperatures of 40°C.

  • What Is UF?+

    Superior to sand filters and traditional media filtration

    As with most conventional filtration methods, sand filters and media filtration require consistent raw water quality to deliver quality effluent, which is not always possible. They also don't provide an absolute barrier. Traditional media filters typically remove particles to down to about 5 microns.

    Ultrafiltration (UF), however, does not suffer from those limitations. This technology uses an ultrafiltration membrane barrier to exclude particles 0.02 to 0.05 microns, including bacteria, viruses, and colloids, meeting increasingly stringent water-quality standards around the world, and providing a stable, reliable, and consistent water quality.

    UF offers:

    • High and consistent product quality measured by turbidity (NTU) or silt density index (SDI).
    • Tolerance to feedwater quality upsets.
    • No use of pretreatment chemicals (polymer, coagulant, pH adjustment) and associated costs for sludge disposal.
    • Small footprint and less weight than media filters.


    When used as a pretreatment for reverse osmosis (RO) , UF also helps reduce fouling of the RO membranes, which can lead to:

    • Reduced chemical cleaning frequency and consequently, lower operating costs and downtime.
    • The potential to operate RO at higher flux, with fewer membranes and vessels — leading to lower capital cost for the RO system.

  • UF Technology Basics+

    Rejecting particles, colloids, and macromolecules

    In ultrafiltration, water and low-molecular-weight substances are passed through an ultrafine membrane by the application of pressure to the system; flow through the membrane is achieved by applying a pressure gradient between the outer and inner walls of the membrane structure. Feed pressure is from 4 to 100 psig (typically < 30) and transmembrane pressure is generally <14 psig.

    Ultrafiltration membranes have pore sizes in the range of 0.02 – 0.05 microns, which contributes to the production of high-quality water; the pore-size range means that the purification process is characterized by a high removal capability of bacteria, viruses, colloids, and silt. The process, however, does not reject particles smaller than the pores, such as dissolved salts or organics; nor does it reject other species such as true color, taste, and odor.

    Ultrafiltration membranes have a service life of three to seven years (and potentially longer). They are commercially available in hollow fiber, tubular, plate, and frame, as well as spiral wound configurations.

  • Hollow Fiber Technology+

    High-filtration performance, high recovery, and energy savings

    Our ultrafiltration modules are made with high-strength, hollow-fiber ultrafiltration membranes that offer the following features:

    • 0.03 μm nominal pore diameter to facilitate high-removal capability for bacteria, viruses, and particulates, including colloids.
    • PVDF polymeric hollow fibers for high strength and chemical resistance.
    • Hydrophilic PVDF fibers for easy cleaning and wettability to help maintain long-term performance.
    • Outside-in flow configuration for high tolerance to feed solids and the use of air scour cleaning.
    • U-PVC housings, which eliminate the need for pressure vessels and are resistant to UV light.


    The outside-in flow configuration is tolerant of wide-ranging feed water qualities and allows air scour cleaning. The dead-end flow offers higher recovery and energy savings. The pressurized vertical shell-and-tube design eliminates the need for separate pressure vessels and allows easy removal of air from cleaning along with integrity testing steps.

    The hollow fiber ultrafiltration membranes are 1.3 mm outside diameter and 0.7 mm inside diameter and are made from PVDF polymer. The fibers are strong due to a combination of PVDF polymer, an asymmetric membrane with smaller pores in the active filtration area, and a high porosity substructure. PVDF membranes offer high chemical resistance (e.g., resistance to chlorine) and are tolerant to temperatures of 40°C.

 
 
 
 
 
 
 
 
 

Our approach to ultrafiltration

 
 
 

Our powerful ultrafiltration product portfolio features IntegraFlux™ Ultrafiltration Modules and IntegraPac™ Ultrafiltration Skids that utilize our latest high permeability XP fiber to improve operating efficiencies and productivity. The modules incorporate PVDF hollow fiber membranes in an outside-in flow configuration with a 0.03 micron nominal pore diameter, making them an excellent choice to protect downstream processes such as reverse osmosis. The modules provide superior performance, with an industry-leading ultrafiltration membrane area with low-energy and chemical consumption, effectively minimizing the number of modules needed for your design. The modules are an excellent choice for high removal capability for viruses, bacteria, suspended solids, colloids, and pathogens from water and have been tested and certified by NSF International under NSF/ANSI Standard 61, and also have NSF/ANSI 419 LRV certifications facilitating safe use in drinking water applications.

Our IntegraFlux™ and IntegraPac™ families of pressurized ultrafiltration (UF) modules give you the flexibility to select standard-grade ultrafiltration modules or premium-grade filtration modules with XP fiber, which provide up to 35 percent higher permeability than previous generation modules and result in improved operating efficiencies and productivity. Our IntegraFlux™ UXA-2680XP UF modules with XP fiber deliver groundbreaking high-flux, low energy performance, and their design makes switching modules easy — no hardware or process changes needed to switch from your lower-pore-size microfiltration (MF) modules.

Our IntegraPac™ skids are pre-engineered, standardized, and ready to assemble. They are comprised of IntegraPac™ modules, auxiliary parts, and piping, and can significantly streamline design, assembly, and installation.

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

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