Membrane Filtration

CRS have utilised membrane filtration technologies in numerous treatment applications throughout Australia.

Membrane filtration is a physical barrier technology that utilises semipermeable membranes to separate suspended solids and high molecular weight solutes. It is fundamentally similar to particle filtration in that it is based on size exclusion, but differs in terms of pore sizes. Membrane microfiltration can achieve separations down to 0.1µm, while ultrafiltration can separate solids from the liquids down to 0.001µm.

UF is commonly used to concentrate protein solutions, paints and treat water, removing solids, bacteria, viruses, larger proteins, colloids and some dyes. However, the pore size still allows some salts and ions to pass through to the permeate, which may cause scaling issues in downstream processes and pipework.

These systems require frequent backwashes to remove foulant build-up on the surface. This is usually achieved through backwashing and occasional Clean In Place (CIP) operations, using chemicals that target specific types of fouling. The types of chemicals used include:

– Acidic solutions for inorganic scale
– Alkali solutions for organics
– Biocides for biological fouling

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