ESPA4-LD Reverse Osmosis Membrane – Ultra Low Energy, Low Fouling Brackish Water Element

Unlock maximum energy savings with the Hydranautics ESPA4-LD, an advanced 8" x 40" low-pressure RO membrane from the ESPA series. Optimized for very low feed pressures and featuring LD (Low Differential) fouling-resistant technology, this element is perfect for brackish water applications where minimizing operating costs and extending cleaning intervals are priorities.

Key Specifications & Performance

• Permeate Flow: 12,000 gallons per day (45.4 m³/day)
• Salt Rejection: 99.2% (99.0% minimum)
• Active Membrane Area: 400 ft² (37.2 m²)
• Feed Spacer: 34 mil (0.86 mm) — promotes low fouling
• Test Conditions: 500 ppm NaCl, 100 psig (0.7 MPa) applied pressure, 77°F (25°C), 15% recovery, pH 6.5–7.0

Configuration: Low Fouling Spiral Wound Membrane Polymer: Composite Polyamide Dimensions: 8" diameter x 40" length (includes brine seal, interconnector, and O-rings)

Standout Advantages

• Ultra-Low Pressure Operation: Performs at just 100 psi test pressure — one of the lowest in the lineup, drastically cutting energy use for pumps and overall system costs.
• LD Fouling Resistance: Wider feed spacer and specialized design reduce colloidal and biofouling, leading to longer run times between cleanings and lower maintenance.
• High Productivity at Low TDS: Excellent for treating lower-salinity brackish water with reliable rejection and high flow.
• Operating Limits:
  • Max Applied Pressure: 600 psig (4.14 MPa)
  • Max Operating Temperature: 113°F (45°C)
  • pH Range (Continuous / Cleaning): 2–10 (1–12)
  • Max Feedwater Turbidity: 1.0 NTU
  • Max Feedwater SDI (15 min): 5.0
  • Max Feed Flow: 85 gpm (19.3 m³/h)
  • Max Pressure Drop per Element: 15 psi
  • Chlorine Tolerance: < 0.1 ppm

Ideal Applications

• Municipal and industrial brackish water desalination with energy constraints
• Low-TDS well water treatment for drinking or process use
• Wastewater reclamation and reuse systems
• Commercial RO plants seeking lowest possible operating pressures
• Installations with conventional pretreatment needing strong anti-fouling performance

Reliable & Ready-to-Use

Each element is packaged in a sealed polyethylene bag with sodium meta-bisulfite preservative for optimal shelf life and immediate performance upon installation.

Price: Competitive through KnappRO Chicago (inquire for volume pricing or current availability).

The ESPA4-LD represents the pinnacle of low-energy RO technology — delivering high output with minimal power input and reduced fouling risk. A smart choice for sustainable, cost-effective water treatment.

Need help selecting the right ESPA model for your system or comparing it to others in the lineup? We're here to assist.

KnappRO Chicago — Quality Hydranautics membranes, affordable prices, and expert guidance.