What is microfiltration?

Like ultrafiltration, microfiltration is a physical barrier where the size of the pores determines which solids are allowed to pass. The pores of a microfiltration membrane are between 10 and 0.1 µm; with ultrafiltration, pore sizes of 0.001 to 0.1 µm are possible.

Microfiltration is available in various forms;

• Filter cartridges
• Filter bags
• Hollow fibre
• Automatic rinsing
• Manual rinsing

In locations with a lot of organic or inorganic material in the water, PB applies microfiltration as a pre-filter. The automatically flushable prefilters can be equipped with cartridges up to 90 microns. The manually flushable units are supplied with filter bags between 5 and 20 microns.

Hollow fibre microfilters are similar to the hollow fibre used in ultrafiltration. The membranes are potted in a filter housing and can be mounted in a similar set-up as Ultrafiltration. PB can also deliver custom made hollow fibre microfiltration.

Microfiltration is applied as a technique for;

• Removal of particles up to 0.1 µm
• Removing bacteria
• Turbidity from beer and wine
• Separating water and oils
• Pre-treatment for UF and NF

Bacteria have a size of approximately 1 µm, which means that microfiltration can remove bacteria. Viruses, however, are not stopped by MF and will remain in the water. Due to the small difference in pore size of MF and bacteria, there is a chance of continued growth by mutation. To prevent this, it is advised to replace microfilters regularly.