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Ultrafiltration (UF) System

Membranes that remove turbidity, colloids and bacteria — a physical barrier ahead of RO or for reuse.

What ultrafiltration is

Ultrafiltration uses hollow-fibre or spiral membranes with pores of about 0.01–0.1 micron. Water passes; suspended solids, colloids, bacteria, protozoa and a large share of viruses and colloidal organics do not. Unlike RO it does not remove dissolved salts, so it runs at low pressure and high recovery (90–95 %). Its two big jobs are protecting RO membranes and producing clear, low-SDI, disinfected water for reuse.

How a UF plant works

Process flow — typical sequence
Pre-screening01Feed pumping andfiltration02Backwash03Chemicallyenhancedbackwash04CIP05Integritytesting06Controls07
  1. Pre-screeningStrainer or disc filter (100–300 micron) protects fibres from debris.
  2. Feed pumping and filtrationDead-end or cross-flow operation through the membrane modules; permeate SDI typically < 3.
  3. BackwashFrequent short reverse flushes with permeate remove the cake from the fibre surface.
  4. Chemically enhanced backwash (CEB)Periodic hypochlorite, acid or caustic backwash removes organic and inorganic foulants.
  5. CIPLonger chemical soak when trans-membrane pressure rises beyond the set limit.
  6. Integrity testingPressure-decay test confirms no broken fibres — essential for disinfection claims.
  7. ControlsPLC-sequenced valves, TMP and flow monitoring, automatic cleaning cycles.

Where UF fits

RO pretreatment

Replaces multigrade filters where SDI or turbidity is high; extends membrane life.

Surface-water treatment

Monsoon turbidity spikes and micro-organisms without chemical clarification.

Tertiary treatment of STP/ETP outlet

Reuse-grade clarity and disinfection for flushing, cooling and process.

MBR

UF membranes inside the biological reactor of an MBR plant.

Process and beverage water

Clear, low-microbe water for food, beverage and pharma pretreatment.

Applications

Industrial RO plants
Pretreatment for difficult borewell, canal and reuse feeds.
Municipal and campus drinking water
Pathogen barrier with low chemical use.
Textile, chemical and food reuse schemes
UF + RO trains.

How we deliver UF

Feed characterisation → flux and module selection → skid, backwash and CEB design → supply, erection, commissioning → performance and integrity monitoring under O&M.

Frequently asked questions

What does ultrafiltration remove?

Suspended solids, turbidity, colloids, bacteria, most viruses and macromolecules — down to about 0.01–0.1 micron. It does not remove dissolved salts; that needs RO.

Where is UF used?

As RO pre-treatment to protect membranes, as tertiary treatment for wastewater reuse, in surface-water treatment for drinking water, and inside membrane bioreactors.

What is SDI and why does it matter for RO?

Silt Density Index measures the fouling potential of feed water. RO manufacturers require SDI below 3–5; UF reliably brings it below 2, which is why UF is the preferred RO pre-treatment.

How often is UF backwashed and cleaned?

Automatic backwash every 20–60 minutes for 30–60 seconds, plus a chemically enhanced backwash daily and a full CIP every few weeks to months depending on feed quality.

Planning a UF or reuse system?

Share your inlet analysis, capacity and location — we reply with a preliminary scheme and budget range within one working day.