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Membrane filtration
UF-580Ultrafiltration — Module Configuration and Barrier Performance
Ten times finer than MF, and the difference matters: UF removes viruses and colloids as well as protozoa, and it is the standard pre-treatment ahead of RO. How that membrane is packaged — fibre, tube, sheet, spiral or ceramic — decides the footprint, the energy and, above all, whether it can be backwashed at all.
Cutaway — Ultrafiltration — Module Configuration and Barrier Performance
WaterColloidsPermeateBackwash
How it works
Finer than MF — At roughly 0.01 µm, UF holds back viruses and colloidal silica as well as everything MF stops. That is why it is the default pre-treatment ahead of RO — it delivers an SDI the RO can live with, whatever the raw water does.
How the membrane is packaged — The same square metre of membrane can be a hollow fibre, a tube, a flat sheet, a spiral or a ceramic monolith. Packing density spans 50 to 900 m²/m³, so the format decides footprint and module count before anything else does. Switch the format above and watch the rack size move.
Flux and TMP — Flux is what you demand; transmembrane pressure is what it costs. Their ratio is permeability, and permeability falling is the single number that tells you the membrane is fouling. Each format has its own workable flux band — ceramic runs at 200 LMH, a submerged flat sheet at 25.
The backwash cycle — Every 30–60 minutes the flow reverses and permeate is pushed back through the membrane, lifting the retained solids off the wall. This is the property that decides what a format can be fed. Spiral-wound and flat sheet cannot do it — spiral because the glue lines will not take reverse pressure, flat sheet because it relaxes and air-scours instead. Select either one and watch the CIP interval collapse.
Integrity — A single broken fibre destroys the barrier while the plant carries on looking normal — flux and TMP barely move. That is why UF is tested by pressure decay: hold air on the permeate side and watch it fall. Above about 20 mbar/min the module comes out.
Choosing a format — Hollow fibre for municipal water, because it backwashes. Tubular when the feed would plug anything else. Flat sheet in mixed liquor. Ceramic when the stream is hot, oxidising or high-value enough to pay for it. Spiral-wound only where the feed arrives clean — dairy, juice, paint recovery — which is why it owns RO and is absent from water-treatment UF.
Outside-in hollow fibre — The default for water treatment, and for one reason above all: it backwashes. Feed sits on the shell side so there is no channel to plug, air scour can reach the fibre surface, and the packing density of around 900 m²/m³ makes the rack small. Municipal drinking water, RO pre-treatment and MBR all use it.
Design parameters
The panel opposite runs the same correlations as the UF-580 design sheet, so the animation and the calculator cannot disagree. Every parameter below is live — drag one and the picture responds.
Parameter
Unit
Default
Range
Module configuration
Format
Hollow fibre outside-in
6 options
Changing format moves the design flux into that format’s own band. Spiral-wound and flat sheet cannot be backwashed.
Duty
Permeate flow
m³/h
50
5 – 350
Design flux
LMH
70
10 – 320
Clean TMP
bar
0.3
0.08 – 1.2
Cycle and integrity
Filtration interval
min
40
15 – 90
Fouling rate
bar/30 min
0.07
0.01 – 0.4
Pressure decay
mbar/min
8
0 – 60
Open the full UF-580 design sheet for the other six inputs, all twenty-seven results with their envelopes, the six equations printed beside the numbers they produce, and a calculation record you can export and put in a design file.
Live parameters
Six of the twelve inputs the UF-580 design sheet takes.
Module configuration
Changing format moves the design flux into that format’s own band. Spiral-wound and flat sheet cannot be backwashed.
Duty
Cycle and integrity
You have an estimate. The design sheet is the justification.
This page sizes the unit on six variables and tells you whether the headline numbers land in range. That is enough to sketch with, and it stays free. What it will not do is survive a design review: it does not show you the equation behind any number, it checks the obvious limits rather than all of them, and there is nothing to file.
The UF-580 design sheet runs the same physics on twelve inputs, reports twenty-seven results against their envelopes, prints the six governing equations beside the numbers they produce, and exports the lot as a calculation record for the design file.