Dow Filmtec Membranes Element for Water Treatment

DOW FILMTEC™ Membranes

DOW FILMTEC Seawater RO Elements for Marine Systems

Features

Improved DOW FILMTEC™ seawater reverse osmosis elements offer the highest productivity while maintaining excellent salt rejection.
• DOW FILMTEC SW30 membrane elements have the highest flow rates available to meet the water demands of both sea-based and land-based desalinators.
• DOW FILMTEC SW30 elements may also be operated at lower pressure to reduce pump size, cost and operating expenses.
• Improved DOW FILMTEC seawater membrane combined with automated, precision element fabrication result in the most consistent product performance available.


Operating Limits
• Membrane Type Polyamide Thin-Film Composite
• Maximum Operating Temperature 113°F (45°C)
• Maximum Operating Pressure 1,000 psi (69 bar)
• Maximum Pressure Drop 15 psig (1.0 bar)
• pH Range, Continuous Operationa 2 - 11
• pH Range, Short-Term Cleaningb 1 - 13
• Maximum Feed Silt Density Index SDI 5
• Free Chlorine Tolerancec <0.1 ppm
a Maximum temperature for continuous operation above pH 10 is 95°F (35°C).
b Refer to Cleaning Guidelines in specification sheet 609-23010.
c Under certain conditions, the presence of free chlorine and other oxidizing agents will cause premature membrane failure. Since oxidation damage is not covered under warranty, DOW FILMTEC recommends removing residual free chlorine by pretreatment prior to membrane exposure. Please refer to technical bulletin 609-22010 for more information.

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 50 psi (3.4 bar).
• Avoid static permeate-side backpressure at all times.