Hydranautics ESNA1-LF-LD Nanofiltration Membrane Element

The ESNA1-LF-LD is a high-performance, low-fouling nanofiltration (NF) membrane from Hydranautics (a Nitto Group Company), engineered for ultra-low-pressure operation while delivering excellent softening and selective contaminant removal. As part of the advanced ESNA series, it combines patented Low Differential Pressure (LD™) technology with a composite polyamide membrane to achieve superior energy efficiency and long-term reliability in brackish water and surface water treatment applications.

Featuring a patented 34 mil feed spacer with biostatic properties, the ESNA1-LF-LD minimizes colloidal fouling, reduces pressure drop, and enhances cleanability — resulting in fewer cleanings, extended membrane life, and lower overall operating costs.

Key Performance Specifications (8" x 40" element):

• Permeate Flow: 9,500 gpd (36.0 m³/day)
• CaCl₂ Rejection: 93% (88% minimum / 97% maximum)
• Expected Calcium Rejection: ~96% in typical 500 ppm well water at 13 gfd flux
• Active Membrane Area: 400 ft² (37.2 m²)
• Feed Spacer: 34 mil (0.864 mm) with biostatic agent

For the 4" x 40" (ESNA1-LF-LD-4040) variant:

• Permeate Flow: 1,900 gpd (7.2 m³/day)
• Active Membrane Area: 80 ft² (7.43 m²)

Tested under standard conditions (500 ppm CaCl₂ solution, 75 psi applied pressure, 77°F / 25°C, 15% recovery), this membrane provides 50–90% overall salt rejection while excelling at the removal of divalent ions (hardness), natural organic matter (NOM), TOC, color, pesticides, bacteria, and viruses.

Ideal Applications:

• Municipal drinking water softening and treatment
• Surface water or well water purification
• Organics, PFAS, and pesticide removal
• Industrial process water softening
• Wastewater reclamation and high-recovery systems
• Food & beverage, power generation, and other facilities requiring partial demineralization without full RO-level desalination

The ultra-low operating pressure (often under 100 psi in real-world conditions) translates to significant energy savings, reduced pump requirements, and lower installation/operating costs compared to traditional brackish water RO membranes. Its low-fouling design makes it particularly effective in challenging feedwaters with higher fouling potential.

Operating Limits:

• Maximum Applied Pressure: 600 psig (4.14 MPa)
• Maximum Operating Temperature: 113°F (45°C)
• pH Range (Continuous): 2–10 (Cleaning: 1–13)
• Maximum Chlorine Concentration: <0.1 ppm

Supplied complete with brine seal, interconnector, and O-rings for straightforward installation in standard pressure vessels.

When your system demands efficient hardness reduction, high organics removal, and minimal energy use without the need for full reverse osmosis, the Hydranautics ESNA1-LF-LD delivers outstanding performance and value. Backed by Hydranautics’ decades of innovation in membrane technology, it offers stable, long-term operation with reduced maintenance — making it a preferred choice for cost-effective, high-quality water production.