The XF33R is a tubular 3 mm ultrafiltration membrane very well suited for the separation of biological sludge or any other high solids application in which high effluent quality is required. Separating at 0,03 micron, this membrane filter allows only water and dissolved matter to pass, rejecting everything that is undissolved. The filtrate can either be used directly in many applications, or be fed into another (RO) treatment system to remove the dissolved matter. The construction of the XF33R allows for backflushing from filtration side to feed side, a cleaning process applied in various heavy-duty operations.



  • Backflushing from filtration side to feed side up to 2 bar
  • Typically vertically mounted
  • Tight cut-off at 0,03 micron
  • Applicable to total suspended solids levels up to 15 g/l biomass
  • High tolerance to hypochlorite cleaning
  • Large pH-range from pH1 – pH13
  • High flux rates 
  •  Easily interchangeable

Functional Description

designed for high solids applications 

The XF33R holds 3 mm tubular UF membranes, capable of treating streams with solid concentrations up to 15,000mg/l. The module can be applied in our Airlift MBR solutions and Aquaflex High Solids UF Solution.

With these ‘V-type’ membranes, with permeate ports on the same side, the orientation is vertical which helps building the skids in this way, supporting the optimized Airlift process.

Utilizing the XF33R's Airlift mode, you can enhance the separation process by employing a combination of air, forward flush, and backflush techniques. These methods help maintain the cleanliness of membranes and help ensure their efficient performance.

Fields of application

The XF33R finds its use primarily in high solids applications, such as separating clean water from biological sludge in membrane bioreactors (MBR’s). The filtrate will be free from solids of any kind and typically have an SDI of < 3, making filtration with the XF33R a good pretreatment method for Reverse Osmosis if all suspended solids needs to be taken out.

The XF33R can be used in the following applications:
  • Sludge separation in Membrane bioreactors (MBR’s)
  • Water recycling in algae production
  • RO pretreatment of feed waters high in suspended solids

Specifications - large scale


Membrane surface area
33 m²
Module dimensions (dxl)
8 inch x 3 meter
Housing material
Membrane material
Hydraulic membrane diameter
3 mm
Nominal pore size
30 nm
1 - 13
Chlorine resistance
250.000 ppm.hrs