ULP31-4040 Ultra-Low-Pressure RO Membrane – 4″ × 40″, 2,000 GPD

The ULP31-4040 Reverse Osmosis Membrane is a high-rejection, ultra-low-pressure membrane element designed for efficient dissolved-solids reduction in commercial and industrial water-treatment systems. Its standard 4-inch × 40-inch configuration supports installation in compatible 4040 pressure vessels and multi-element RO equipment.

Under specified test conditions, the current ULP31-4040 configuration provides a nominal permeate flow of 2,000 gallons per day (approximately 7.6 cubic meters per day) with a stable salt-rejection rate of 99.6%. This performance makes the membrane suitable for systems where higher permeate quality is prioritized alongside energy-efficient, ultra-low-pressure operation.

The spiral-wound element provides approximately 100 square feet of active membrane area and uses a 28-mil feed spacer. Its combination of high salt rejection, commercial permeate production and standard 4040 dimensions supports integration into new equipment and compatible membrane-replacement applications.

The ULP31-4040 is intended for appropriately pretreated, low-salinity feedwater such as qualifying municipal water, groundwater and surface water. Proper pretreatment is essential for controlling sediment, hardness, scale, iron, organic fouling and oxidizing chemicals that could reduce performance or shorten membrane life.

Technical Specification

Testing Conditions

Testing Pressure: 150 psi (1.03MPa)

Testing Solution Temperature: 25 ℃

Concentration of Testing Solution (NaCl): 1500ppm

pH value of Testing Solution: 7.5

Recovery Rate of Single Element: 15%

Operation Limits & Conditions

Max. Working Pressure: 600psi（4.14MPa)

Max. Volume of Feed Water: 16gpm（3.6 m3/h）

Max. Temperature of Feed Water: 45℃

 Max. Feed water SDI15: 5

pH Range of Feed Water during Continuous Operation: 3～10

pH Range of Feed Water during Chemical Cleaning: 2～12

Residual Chlorine Concentration of Feed Water : ＜0.1ppm

Max. Pressure Drop of Single Membrane Element: 15psi（0.1MPa）

Max. Pressure Drop of Single Pressure Vessel with Six RO Membranes: 50psi（0.34MPa）

Applications

◎ Drinking water production, such as: packaged water, direct drinking water, food processing water, etc.

◎ Purified water production, such as: pharmaceutical water, medical water, electronics water, etc.

Shipping Information

Optimal Purity Solutions is committed to fast, reliable, and professional fulfillment for our authorized dealer network.

Fulfillment & Processing

• Order Processing: Most in-stock orders ship within 1–2 business days

• Custom/OEM Builds: Lead times vary by configuration; your sales representative will confirm timelines

Shipping Coverage

• Domestic: Nationwide shipping throughout the United States

• International: Available for qualified distributors (terms and transit times vary)

Carriers & Methods

• Shipments are sent via trusted national freight and parcel carriers

• LTL/FTL freight available for pallets and bulk orders

• Expedited shipping options available upon request

Packaging & Handling

• Products are professionally packaged to protect against damage in transit

• Palletized and freight shipments are secured and labeled to industry standards

Tracking & Support

• Tracking information is provided once your order ships

• Our logistics team is available to assist with routing, delivery coordination, and special requirements

Important Notes

• Shipping costs are calculated based on weight, dimensions, destination, and service level

• Damages or discrepancies must be reported within 48 hours of delivery

• Products are sold exclusively through authorized water treatment dealers and partners