Industrial membrane filtration plants from GEA Niro
Industrial membrane filtration plants from GEA Niro

Industrial membrane filtration plants were introduced to the dairy industry in the beginning of the 1970's. The basis for using membrane filtration in the dairy industry is that dry matter components in milk and whey particles consist of different sizes. By selecting filters/membranes of differrent pore sizes and applying pressure on the product to be filtered, it is possible to divide the milk and whey in different fractions. What passes the filter/membrane = permeate and what does not pass = retentate.


Particles Diameter
Fatglobules (and bacterias) 500-10,000 nm
Casein particles 10-300 nm
Whey Protein 3-6 nm
Lactose Approx. 1 nm
Salts 0,4-1 nm
Water Approx. 0,3 nm

What is membrane filtration used for?
Today, membrane filtration is used in the Food & Dairy industry and likewise in other process plants delivered by the GEA Group.

There are four kinds of membrane filtration:

  • Reverse Osmosis is used to remove water from a product to increase the solids content, evaporator condensate is often 'polished' by reverse osmosis, so that it can be used elsewhere in the dairy.
  • Nanofiltration is mainly used to remove the monovalent ions from whey. A partly demineralization and water removal is obtained.
  • Ultrafiltration is typically used for whey, where the whey proteins are separated to form a product with 35, 60 or 80 % WPC. If ultra filtration is applied to skim milk, Milk Protein Concentrate is obtained. The protein fractions are typically evaporated in multi-effect evaporators with either TVR or MVR recompression to save steam, before spray drying.
  • Microfiltration is a low pressure membrane process for separating colloidal and suspended particles in the range of 0.05-10 microns and as such used for bacteria removal.