DOW FILMTEC NF270-4040 Membrane

Product Description

The DOW FILMTEC NF270 membrane elements are ideal for removing a high percentage of TOC and THM precursors with medium to high salt passage and medium hardness passage. The DOW FILMTEC NF270 membrane is an ideal choice for surface water and groundwater where good organic removal is desired with partial softening.


  • Good organic (NOM) removal
  • Partial softening preserves water character
  • High flux results in high yields
  • 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 Active Area Applied Pressurer Permeate Flow Rate Stabilized Salt Rejection (%)
ft2 (m2) psig (bar) GPD (m3/j)
NF270-4040 149987 82 (7.6) 70 (4.8) 2,500 (9.5) 97.0
Operating Limits
  • Membrane Type Polyamide Thin-Film Composite
  • Maximum Operating Temperature 113°F (45°C)
  • Maximum Operating Pressure 600 psi (41 bar)
  • Maximum Feed Flow Rate: 4040 elements 16 gpm (3.6 m3/hr)
  • Maximum Feed Flow Rate: 2540 elements 6 gpm (1.4 m3/hr)
  • Maximum Pressure Drop: Tape wrapped 13 psig (0.9 bar)
  • Maximum Pressure Drop: Fiberglassed 15 psig (1.0 bar)
  • pH Range, Continuous Operation 2 - 11
  • pH Range, Short-Term Cleaning (30 min.) 1 - 12
  • Maximum Feed Silt Density Index SDI 5
  • Free Chlorine Tolerance 0.1 ppm
  • Production of municipal drinking water



(1 review) Write a Review
  • 5
    Great filter housing

    Posted by Ion M. on Apr 11th 2018

    Worked highly efficiently!

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