Meaningful protection for your water treatment processes
(PP), or polyvinylidenefluoride (PVDF). without sacrificing performance.
ltrafiltration or UF is a press
ure-driven membrane separation process that helps removes particulate matter from aqueous solutions such as water. UF
membranes typically have pore sizes in the range of 0.01 to 0.10 μm and efficiently remove bacteria and most viruses, colloids and silt. The smaller the nominal pore size, the higher the removal efficiency. Most materials that are used in UF are polymeric and are naturally hydrophobic, such as polysulfone (PS), polyethersulfone (PES), polypropylene
DOW UF membrane is made from high-grade polymeric PVDF material to form a hollow fiber membrane that is very durable and less prone to breakage. The hollow fiber has a dense layer or skin on both the inside and outside surfaces, forming a double-walled structure that contributes to its strength. In addition, its fouling resistance is improved by making the membrane surface more hydrophilic than the underlying PVDF polymer. With uniform pore size and outside-in flow, the DOW UF membrane creates a barrier
How DOW Ultrafiltration Works
DOW UF modules utilize a double-walled hollow fiber H-PVDF membrane with a very small pore diameter for excellent removal of particulate matter and bacteria, and most viruses and colloids. Despite the small pore diameter, the membrane has a very high porosity, resulting in a stabilized flux similar to that of micro-filtration (MF). Typically, DOW UF is operated at a constant permeate flow. The transmembrane pressure (TMP) will naturally increase over time, and the module can be cleaned by back-washing and air-scouring to remove the fouling layer for longer service life.
Advantages of DOW UF Technology
Low fouling: DOW UF modules are made from H-PVDF material, which has excellent chemical resistance to strong levels of disinfectants such as peroxide or hypochlorite, allowing sufficient removal of bacterial growth. Very fine pore diameter: With a nominal pore diameter of 0.03 μm, DOW UF technology effectively removes pathogens, most viruses and bacteria. In addition, the membrane’s high porosity allows high flux operation at a given transmembrane pressure. Durable double-walled fiber structure: The distinct structure provides excellent durability and resistance against breakage, even with periodic cleaning procedures to remove fouling. Outside-in flow configuration: Systems designed with DOW UF use an outside-in flow configuration, which allows for low clogging and high solids loading, high flow area and easy cleaning. Dead-end or concentrate bleed capabilities: Although the primary flow design is dead-end filtration, modules can be easily adapted to a concentrate bleed mode. Simple, modular design: DOW UF modules can be configured in a simple modular design providing a compact footprint.
DOW UF technology uses double-walled hollow fibers, which are more durable and less prone to breakage than single-walled hollow fibers.
Typical DOW UF Operating Specifications
Fiber Physical Properties Configuration (fluid flow) Hollow Fiber (outside/in) Maximum Operating Transmembrane Pressure (TMP) Typical Process Conditions SI US
Nominal Pore Diameter
0.03 microns SI US
Maximum Backwash Pressure
Hollow Fiber ID
Hollow Fiber OD
0.051” Total Suspended Solids (TSS)
Maximum 100 ppm
Typical 50 ppm
Operating Ranges SI US
Typical Filtrate Flux Range @ 25°C
40 – 120 lmh
24 – 70 gfd
20 to 60 minutes
Temperature (limited by UPVC)
40 to 120 seconds
Maximum Inlet Module Pressure
Typical Clean in Place Frequency
1 to 3 months
Air Scouring Frequency
0 times per day to Backwash Frequency
NaOCl, Cleaning Maximum
Chemically Enhanced Backwash Frequency
As needed with solutions of NaOCl/ Alkali and/or Acid
NaOH/NaOCl, HCl, Citric Acid, Oxalic Acid 4
See installation/operation guide for more detail.
Typical DOW UF Module Specifications
SFX-2660 Series (6-inch diameter) SI Length - L Length - L1 Length - L2 Length - L3 Diameter - D Width - W Module Surface Area Volume per Module Weight (water filled) Shipping Weight (w/o packaging) 1860 mm 1500 mm 1610 mm 1710 mm 165 mm 250 mm 33 m2 16 L 41 kg 25 kg US 73.2” 59.1” 63.4” 67.3” 6.5” 9.8” 355 ft2 4.2 gal 90 lbs 55 lbs SFX-2680 Series (6-inch diameter) SI 2360 mm 2000 mm 2110 mm 2210 mm 165 mm 250 mm 44 m2 20 L 53 kg 33 kg US 92.9” 78.7” 83.1” 87.0” 6.5” 9.8” 474 ft2 5.3 gal 117 lbs 73 lbs SFX-2860 Series (8-inch diameter) SI 1860 mm 1500 mm 1630 mm 1820 mm 225 mm 342 mm 51 m2 35 L 83 kg 48 kg US 73.2” 59.1” 64.2” 71.7” 8.9” 13.5” 549 ft2 9.3 gal 183 lbs 106 lbs
SFX-2660 and SFX-2680 Series (6-inch diameter)
SFX-2860 Series (8-inch diameter)
“X” refers to either “P” Pretreatment or “D” Drinking Water. See UF Technical Manual for more detail.
The design of DOW UF modules are engineered to allow system designers flexibility to meet their exact needs from small modular skids to large plants, resulting in an efficient footprint that can be easily expanded.
For more information, contact us: North America 1-800-447-4369 Latin America 55-11-5188 9980 Europe +800 3 694 6367 Pacific +800 7776 7776 Japan (813) 5460 2100 China (86) 21 2301 9000
NOTICE: No freedom from any patent owned by Seller or others is to be inferred. Because use conditions and applicable laws may differ from one location to another and may change with time, Customer is responsible by determining whether products and information this document are appropriate for Customer’s use and for ensuring that Customer’s workplace and disposal practices are in compliance with applicable laws and other government enacents. Seller assumes no obligation or liability for the information in this document. NO WARRANTIES ARE GIVEN; ALL IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE ARE EXPRESSLY EXCLUDED.
June 2008 Published in U.S.A.
Trademark of The Dow Chemical Company (“Dow”) or an affiliated company of Dow
Form No. 795-00005-0608XBBI