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ReviewedLast reviewed: 2026-06-20

Ultrafiltration

Ultrafiltration (UF) is a low-pressure membrane process that removes suspended solids, colloids, bacteria and most viruses by size exclusion, widely used for drinking-water clarification and as pretreatment ahead of reverse osmosis.

Role in treatment trains

UF provides an absolute physical barrier to particulate and microbial contaminants without chemical coagulant doses that sedimentation requires, producing consistent low-turbidity filtrate regardless of feed swings. It does not remove dissolved salts or small organics, so it is paired with RO/NF when demineralization is required.

As RO pretreatment, UF delivers a stable, low-fouling feed that extends membrane life — a pairing standard in modern desalination and reuse plants. Hollow-fibre UF is manufactured at large scale by suppliers including Litree, Toray and DuPont.

References
  1. [1]Water Treatment: Principles and Design (MWH). John Wiley & Sons, 2012.
  2. [2]Ultrafiltration and Microfiltration Handbook. CRC Press, 2015.