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Packaged ultrafiltration · No backwash · Often no coagulant
Scrub UF: ultrafiltration that keeps scrubbing itself clean.
Flat-sheet UF in an open tank, with scrubbing media that continuously wipes fouling off the membrane while it runs. In many cases the pretreatment ahead of it is a fine screen, so the train can be shorter than coagulation, clarification and media filters, with no backwash pump and no backwash tank.
What we do in Poughkeepsie: Assembled in Poughkeepsie, NY. In our Poughkeepsie shop we build frames and assemble units.
At a glance
What Scrub UF is built to do.
| Item | Scrub UF (typical) |
|---|---|
| Membrane | Flat-sheet PES UF, hydrophilic, about 0.04 µm nominal pore size |
| Filtration | Submerged, low-pressure suction from an open tank |
| Fouling control | Circulating scrubbing media wipes the sheet surface while the unit runs. Screens keep the media in the unit |
| Backwash | None |
| Pretreatment | Often a fine screen only. Depends on the feed |
| Design flux | 9–12 GFD (15–20 LMH); peak 15 GFD (25 LMH). May run higher on clean water |
| Permeate quality | Turbidity typically below 1 NTU and often below 0.1 NTU. SDI typically below 4, suitable as RO feed in many cases |
| Recovery | 90% or better, depending on feed and how concentrate is discharged |
| Chemical clean (CIP) | Often every few weeks to about 1–2 months on suitable feeds. Many pressurized UF systems are cleaned about weekly |
| Membrane life | Reference data often plan on 5+ years. Life depends on the feed, flux and cleaning |
| Control | Automated, with remote monitoring available |
Typical values from reference installations, test data and design studies. Your proposal sets the design point and any guaranteed values for your feed.
One design study
A shorter process than the usual UF trains.
| Item | Scrub UF (submerged flat sheet) | Submerged hollow fiber | Pressurized UF |
|---|---|---|---|
| Pretreatment in the study | Fine screen | Fine screen | Coagulation, flocculation, sand filter and screen |
| Flux in the study | About 33 GFD (56 LMH) | About 24 GFD (40 LMH) | About 31 GFD (53 LMH) |
| Membrane area for the same duty | Lowest in the study | Highest in the study | Similar to Scrub UF in the study |
| Backwash | None | Yes | Yes, with a dedicated pump |
| Chemical clean | About every 1–2 months | Daily maintenance clean plus monthly CIP | About every 7 days |
| Specific energy in the study | About 0.5 kWh/kgal (0.13 kWh/m³) | About 0.6 kWh/kgal (0.15 kWh/m³) | About 1.4 kWh/kgal (0.36 kWh/m³) |
| Coagulant and chemical sludge | None in the study case | Depends on design | Coagulant required; produces sludge |
| Membrane life in the study | 5+ years | 3+ years | 3+ years |
From one engineering design study for about 264,000 gpd (1,000 m³/d) of pretreated, low-solids industrial water. Results on other feeds will differ. Our proposals use 9–12 GFD (15–20 LMH), peak 15 GFD (25 LMH), unless pilot data supports more. May run higher on clean water. Hollow fiber can be the better choice on some very difficult feeds, so we size each job on its own water.
Where it fits
Applications
| Duty | What Scrub UF is asked to do | What to plan for |
|---|---|---|
| RO pretreatment | Storm water and surface water to RO, often after a fine screen, instead of coagulation, clarification and media filters | Typical permeate SDI below 4. In one storm-water reference case, solid waste was about 2.8 versus 8.3 US tons/month |
| Industrial water reuse | Textile and denim wash water, cooling water and process water, ahead of NF or RO where the reuse spec needs it | UF removes particulate and colloidal color, not all dissolved color. Plan ozone, GAC or NF where the color limit is tight |
| Surface and spring water | Direct filtration of surface, spring or groundwater, in many cases without flocculant | One spring-water case: 11–40 NTU raw to permeate below 0.3 NTU. Potable use must meet state and federal requirements; certification is reviewed per project |
UF only
Scrub is a UF platform, not an MBR biomass platform. For biological treatment, start with Swing or Palisade.
Packaged or multi-cell
Independent packaged units for small plants or tight access. A multi-cell tank, with one cell offline while the others produce, is confirmed per project.
Try it first
The Scrub-UF80, 861 ft² (80 m²), ships as a packaged unit to buy or rent for a pilot.
Selected units
From 861 ft² (80 m²) to 11,300 ft² (1,050 m²).
| Model | Membrane area | L × W × H | Design permeate* |
|---|---|---|---|
| Scrub-UF80 | 861 ft² (80 m²) | 3'-3" × 3'-3" × 5'-11" (1,000 × 1,000 × 1,800 mm) | 5–7 gpm 7,800–10,300 gpd (29–38 m³/d) |
| Scrub-UF260-1 | 2,800 ft² (260 m²) | 3'-11" × 7'-3" × 7'-5" (1,200 × 2,200 × 2,250 mm) | 17–23 gpm 25,200–33,600 gpd (94–125 m³/d) |
| Scrub-UF350-1 | 3,770 ft² (350 m²) | 3'-11" × 7'-3" × 8'-4" (1,200 × 2,200 × 2,530 mm) | 24–31 gpm 33,900–45,200 gpd (126–168 m³/d) |
| Scrub-UF260-2 | 5,600 ft² (520 m²) | 7'-7" × 7'-3" × 7'-5" (2,300 × 2,200 × 2,250 mm) | 35–47 gpm 50,400–67,200 gpd (187–250 m³/d) |
| Scrub-UF350-3 | 11,300 ft² (1,050 m²) | 11'-0" × 7'-3" × 8'-4" (3,350 × 2,200 × 2,530 mm) | 71–94 gpm 101,700–135,600 gpd (378–504 m³/d) |
*Design permeate at 9–12 GFD (15–20 LMH), peak 15 GFD (25 LMH). May run higher on clean water; we confirm that by pilot or reference data before we design to it. Septic and low-oversight duty, where an MBR is the right tool, is 6 GFD (10 LMH) or less. A 0.16 in (4.0 mm) sheet family is also available (Scrub-UF210 / UF280).
Larger plants can use a multi-cell tank, with each cell taken offline for cleaning while the others keep producing. Configuration is confirmed per project. Units are assembled in Poughkeepsie, NY.
Questions
Common questions
What flux do you design to?
9–12 GFD (15–20 LMH), with 15 GFD (25 LMH) for short peaks. May run higher on clean water. We confirm a higher flux by pilot or reference data before we design to it.
How is it cleaned without backwash?
Screen-retained scrubbing media circulates in the tank and wipes the fouling layer off the sheets while they run. A periodic tank drain removes solids, and a chemical soak is done every few weeks to months on suitable feeds.
Will UF remove color?
Partly. UF removes particulate and colloidal color. Dissolved dye usually needs a polishing step after UF, such as ozone, GAC or NF. We do not promise full color removal.
Is Scrub UF an MBR?
No. Scrub is a UF platform. For biological treatment with membranes, see Swing MBR or Palisade, or the MBR overview.
Is the integrated tank a standard product?
A multi-cell tank can be part of a larger plant. The configuration is confirmed per project.
UF duty outside an MBR?
Send us your feed water data. We will size Scrub UF from 861 to 11,300 ft² (80 to 1,050 m²), or set up a Scrub-UF80 pilot.