The DOW FILMTEC NF270-400/34i element is a high area, high productivity element designed to remove a high percentage of TOC and THM precursors while having a medium to high salt passage and medium hardness passage. It is an ideal element for surface and groundwater applications where good organic removal is desired with partial softening in order to maintain a minimum level of hardness for organoleptic properties and preservation of distribution networks. The high active area membrane combined with low net driving pressure of the membrane allows the removal of these compounds at low operating pressure. It uses a 34 mil feed spacer to lessen the impact of fouling on pressure drop across a vessel and enhance cleaning effectiveness. The iLEC™ interlocking end caps reduce system operating costs and the risk of o-ring leaks that can cause poor water quality.
FILMTEC NF270-400/34i Membrane Elements
- Good organic (NOM) removal
- Partial softening preserves water character
- High flux results in high yields
- Low energy usage reduces power consumption and costs
- Durable with good cleanability for long element life
- Thicker feed spacer delivers better tolerance of suspended solids and enables more efficient cleaning of organic material from the element
- FILMTEC performance and quality
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.
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.
• 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 permeate-side backpressure at all times.
|Product||Part number||Nominal Active Surface Area ft2 (m2)||Product Water Flow Rate gpd (m3/d)||Stabilized salt rejection (%)|
|CaCl2||14,700 (55.6)||40 – 60|
The DOW FILMTEC™ NF270-400/34i Nanofiltration element is a high area and high productivity element offering an industry wide unique combination of features:
• High removal rate of salts, including nitrates and iron,
• High removal rate of organic compounds such as pesticides, herbicides, and THM precursors.
• A 34 mil feed spacer to lessen the impact of fouling on pressure drop across a vessel and to enhance cleaning effectiveness.
The DOW FILMTEC™ NF270-400/34i is listed to ANSI/NSF61. For more information visit: http://www.nsf.org/Certified/PwsComponents
In addition, the DOW FILMTEC™ NF270-400/34i includes the typical DOW FILMTEC product features:
• iLEC™ interlocking end caps reduce system operating costs and the risk of o-ring leaks.
• The oxidative free membrane manufacturing process results in high membrane robustness and long term stable performance.
• The widest pH range for cleanings (pH1 to pH12) allows effective cleanings even in cases of severe fouling.
• The automated, precision fabrication gives a greater number of shorter membrane leaves thus reducing fouling while maximizing element efficiency.
- Membrane Type Polyamide Thin-Film Composite
- Maximum Operating Temperature 113ºF (45ºC)
- Maximum Operating Pressure 600 psig (41 bar)
- Maximum Pressure Drop 15 psig (1.0 bar)
- pH Range, Continuous Operation 3 - 10
- pH Range, Short-Term Cleaning (30 min.) 1 - 12
- Maximum Feed Flow SDI 5
- Free Chlorine Tolerance <0.1 ppm
Ideal Applications Include:
- Production of municipal drinking water