CSM RE2521-BN

Summary

Product identification

The RE 2521-BN is a normal grade RO (Reverse Osmosis) element with a thick feed spacer, designed for brackish water applications.

Product Specifications

• Permeate flow rate: 250 GPD (1.1 m³/day)
• Stabilized salt rejection: 99.7%
• Effective membrane area: 10 ft² (0.93 m²)
• Minimum salt rejection: 99.4%
• Permeate flow rate variation: No more than 15% between elements.

The stated product performance is based on data taken after 30 minutes of operation at the following test conditions:

• 2,000 mg/L NaCl solution
• 225 psig (1.5 MPa) applied pressure
• 8% recovery
• 77 °F (25 °C)
• pH 6.5–7.0

Membrane Details

• Membrane type: Thin-Film Composite
• Membrane material: Polyamide (PA)
• Element configuration: Spiral-Wound, FRP Wrapping

Mechanical / Hydraulic

• Dimensions:
  • Length (A): 21.0 inch (534 mm)
  • Diameter (B): 2.5 inch (64 mm)
  • C: 0.75 inch (19.1 mm)
  • D: 1.1 inch (28 mm)
  • E: 1.1 inch (28 mm)
• Fit: All RE2521 elements fit nominal 2.5 inch (64 mm) I.D. pressure vessels.
• Included with each element: One brine seal, one interconnector (coupler), and four o-rings.
• Packaging: Elements are vacuum sealed in a polyethylene bag containing 1.0% SBS (sodium bisulfite) solution and individually packaged in a cardboard box.

Operating limits

• Max. Pressure Drop / Element: 15 psi (0.1 MPa)
• Max. Operating Pressure: 600 psi (4.14 MPa)
• Max. Feed Flow Rate: 6 gpm (1.36 m³/hr)
• Min. Concentrate Flow Rate: 1 gpm (0.23 m³/hr)
• Max. Operating Temperature: 113 °F (45 °C)
• Operating pH Range: 2.0–11.0
• CIP pH Range: 1.0–13.0
• Max. Turbidity: 1.0 NTU
• Max. SDI (15 min): 5.0
• Max. Chlorine Concentration: < 0.1 mg/L

Design Guidelines (Flux in gfd)

• Wastewater Conventional (SDI < 5): 8–12 gfd
• Wastewater Pretreated by UF/MF (SDI < 3): 10–14 gfd
• Seawater, Open Intake (SDI < 5): 7–10 gfd
• Seawater, Beach Well (SDI < 3): 8–12 gfd
• Surface Water (SDI < 5): 12–16 gfd
• Surface Water (SDI < 3): 13–17 gfd
• Well water (SDI < 3): 13–17 gfd
• RO permeate (SDI < 1): 21–30 gfd

Saturation Limits (Using Antiscalants)

• Langlier Saturation Index (LSI): < +1.5
• Stiff and Davis Saturation Index (SDSI): < +0.5
• CaSO₄: 230% saturation
• SrSO₄: 800% saturation
• BaSO₄: 6,000% saturation
• SiO₂: 100% saturation

Note: The above saturation limits are typically accepted by proprietary antiscalant manufacturers. It is the user’s responsibility to ensure proper chemical(s) and concentration are dosed ahead of the membrane system to prevent scale formation anywhere within the membrane system. Membrane elements fouled or damaged due to scale formation are not covered by the limited warranty.

General Handling Procedures

• Elements contained in boxes must be kept dry at room temperature (7–32 °C; 40–95 °F) and should not be stored in direct sunlight.
• If the polyethylene bag is damaged, a new preservative solution (sodium bisulfite) must be added and air-tight sealed to prevent drying and biological growth.
• Permeate from the first hour of operation should be discarded to flush out the preservative solution.
• Elements should be immersed in a preservative solution during storage, shipping, and system shutdowns to prevent biological growth and freezing.
  • The standard storage solution contains 1% by weight sodium bisulfite or sodium metabisulfite (food grade).
  • For short-term storage (one week or less), 1% by weight sodium metabisulfite solution is adequate for preventing biological growth.
• Keep elements moist at all times after initial wetting.
• Avoid excessive pressure and flow spikes.
• Only use chemicals compatible with the membrane elements and components. Use of such chemicals may void the element limited warranty.
• Permeate pressure must always be equal to or less than the feed/concentrate pressure. Damage caused by permeate back pressure voids the element limited warranty.

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Disclaimer: This summary is based on extracted text and may not include all figures, footnotes, or the latest revisions present in the official PDF datasheet. For contractual data and complete information, please refer to the specific OEM PDF revision used on your project.

Official datasheet (PDF)

PDF datasheet