UF Membrane Modules

Ultrafiltration (UF) membranes filter at a pore size of 0.01–0.1 µm — a range that reliably rejects bacteria, viruses, colloids, macromolecules, and turbidity while passing dissolved salts and small organics through to the permeate. This selective barrier makes UF an effective pre-treatment to reverse osmosis and a standalone clarification step for industrial water reuse. The two dominant membrane materials are polyvinylidene fluoride (PVDF) and polyethersulfone (PES): PVDF is preferred for industrial applications because of its high chlorine tolerance — up to 200,000 ppm·h cumulative — which enables aggressive hypochlorite CIP cleaning without degrading the membrane polymer. For a broader overview of UF as a technology, see our ultra-filtration page.

UF modules are available in two principal configurations. Hollow fiber modules — available as pressurised outside-in or inside-out — are commonly used for pre-RO treatment and standalone water polishing; they achieve high permeate fluxes of 40–120 LMH with a compact footprint. Flat-sheet submerged modules are the standard configuration in membrane bioreactors (MBR), where they are immersed directly in the aeration tank containing activated sludge and operate under vacuum suction at lower fluxes of 10–30 LMH. Transmembrane pressure (TMP) is the key operating parameter monitored across both configurations: rising TMP at constant flux signals fouling. Membranes are maintained through regular backwashing every 15–60 minutes and periodic CIP with sodium hypochlorite or citric acid. For more on MBR system design and operation, see our MBR technology page.

In India, UF membranes are applied across three main contexts: as the core filtration element in MBR-based sewage treatment plants (STPs), as pre-treatment ahead of RO in zero liquid discharge (ZLD) systems where a low-SDI feed is essential to protect the RO elements, and as polishing stages in industrial water reuse schemes. Spans supplies PVDF hollow fiber and flat-sheet UF modules on a brand-neutral basis — matching replacement modules to existing cassette frames, skids, and manifolds where direct compatibility can be verified — supporting both new installations and ongoing membrane replacement programmes. For related ZLD applications, see our zero liquid discharge page; for MBR systems, see our MBR technology page.