DOW FILMTEC XLE-2521 Membrane

Product Description

DOW FILMTEC XLE-2521 reverse osmosis (RO) elements offer high quality water for small commercial systems purifying less than one gallon per minute (0.2 m3/d) of RO water. DOW FILMTEC XLE extra low energy elements operate at the lowest pressure available in the industry today, resulting in lower energy costs and enabling system builders to use lower cost components.


  • High flux results in high yields
  • High rejection provides good water quality
  • Filmtec performance and quality.

Important Information

Proper start-up of reverse osmosis water treatment systems is essential to prepare the membranes for operating service and to prevent membrane damage due to overfeeding or hydraulic shock. Following the proper start-up sequence also helps ensure that system operating parameters conform to design specifications so that system water quality and productivity goals can be achieved.

Before initiating system start-up procedures, membrane pretreatment, loading of the membrane elements, instrument calibration and other system checks should be completed.

Please refer to the application information literature entitled “Start-Up Sequence” (Form No. 609-02077) for more information.

Operation Guidelines

Avoid any abrupt pressure or cross-flow variations on the spiral elements during start-up, shutdown, cleaning or other sequences to prevent possible membrane damage. During start-up, a gradual change from a standstill to operating state is recommended as follows:

  • Feed pressure should be increased gradually over a 30-60 second time frame.
  • Cross-flow velocity at set operating point should be achieved gradually over 15-20 seconds.
  • Permeate obtained from first hour of operation should be discarded.

General Information

  • Keep elements moist at all times after initial wetting.
  • If operating limits and guidelines given in this bulletin are not strictly followed, the limited warranty will be null and void.
  • To prevent biological growth during prolonged system shutdowns, it is recommended that membrane elements be immersed in a preservative solution.
  • The customer is fully responsible for the effects of incompatible chemicals and lubricants on elements.
  • Maximum pressure drop across an entire pressure vessel (housing) is 30 psi (2.1 bar).
  • Avoid static permeate-side backpressure at all times.
Product Part Number Applied Pressure psig (bar) Permeate Flow Rate gpd (m3/d) Stabilized Salt Rejection (%)
XLE-2521 154530 100 (6.9) 365 (1.4) 99

New DOW FILMTEC™ XLE elements offer better system performance and economics by operating at very low applied pressure. XLE membrane, made with a patented technology, provides consistent and reliable system performance. And for added convenience, XLE elements are available in a dry state for rapid start-up (see Figure 1 on reverse). The new XLE series of elements replaces TW30LE elements which were made with an older membrane technology.

Operating Limits
  • Membrane Type Polyamide Thin-Film Composite
  • Maximum Operating Temperature 113°F (45°C)
  • Maximum Operating Pressure 600 psi (41 bar)
  • Maximum Pressure Drop 13 psig (0.9 bar)
  • pH Range, Continuous Operation 2 - 11
  • pH Range, Short-Term Cleaning 1 - 13
  • Maximum Feed Silt Density Index SDI 5
  • Free Chlorine Tolerance <0.1 ppm
  • Commercial Water treatment systems
  • Food service
  • Medical and research institutions
  • Hospitality industry

DOW FILMTEC XLE-2521 Membrane


(2 reviews) Write a Review
  • 5
    Best filter housing

    Posted by Ariclene S. on May 13th 2019

    Amazing filtration capabilities!

  • 5
    Best price

    Posted by Alfredo Ê. on Jan 11th 2018

    Productive items that did the job well

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