ULP31-4021 Ultra Low Pressure RO Membrane | Energy Saving Brackish Water Desalination Membrane
Introduction:If you are sourcing reliable replacement RO membrane for small commercial water treatment projects, our factory supplies premium Liquid Filters and filtration consumables including Self Cleaning Filter, alongside ULP31-4021 ultra low pressure RO membrane element tailored for brackish water desalination. This 4021 size reverse osmosis membrane adopts advanced polyamide thin film composite membrane sheet, delivering stable salt rejection under reduced operating pressure. It achieves steady permeate flow with lower energy consumption, effectively removing dissolved salts, silica, colloids and organic contaminants from well water and surface raw water. As a cost-saving alternative to imported membrane brands, it fits compact RO skids, helping water treatment contractors cut long-term electricity and maintenance costs.
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Product Introduction
ULP31-4021 ultra low pressure RO membrane is a newly developed 4021 specification element within our ULP series reverse osmosis membrane lineup, designed specially for small and medium commercial brackish water purification systems. Sitting between 2540 and 4040 membrane sizes, this model fills the market gap for compact water treatment skids that need higher water output than 2540 membranes but cannot accommodate the larger 4040 elements. To secure stable long-term operation of this RO element, matched pre-treatment equipment such as Liquid Filters, Self Cleaning Filter are strongly recommended to intercept suspended solids and large particles before raw water enters the membrane housing. Traditional imported low-pressure RO membranes often demand relatively high startup pressure, which increases power consumption for small-scale projects. Our ULP31-4021 optimizes the polyamide membrane surface structure, enabling effective desalination performance at much lower operating pressure. It is widely used for well water purification, municipal tap water deep treatment and small industrial pure water production. As a drop-in replacement element, it matches standard 4-inch membrane housings, making membrane replacement simple for system integrators and end users.
Working Principle
The ULP31-4021 RO membrane operates based on the principle of reverse osmosis. Under appropriate driving pressure, water molecules pass through the dense polyamide thin composite layer of the membrane sheet, while dissolved salts, heavy metal ions, colloidal particles and macromolecular organic pollutants are intercepted on the membrane surface.
Thanks to the optimized ultra-low pressure membrane formula, this element requires less pressure to push water through the membrane compared with conventional brackish water RO membranes. It reduces the load on high-pressure pumps, lowering energy consumption. The membrane surface also features improved hydrophilicity, slowing the accumulation of foulants and extending the service cycle between membrane cleanings.
Technical Specifications
| Item | Parameter |
|---|---|
| Model | ULP31-4021 |
| Membrane Type | Ultra Low Pressure Brackish Water RO Membrane |
| Dimension | 4.0 inch × 21 inch |
| Active Membrane Area | 33 sq.ft |
| Test Pressure | 100 psi (0.69 MPa) |
| Permeate Flow Rate | 1100 GPD |
| Stabilized Salt Rejection | 99.2% |
| Maximum Operating Pressure | 300 psi |
| Operating Temperature Range | 5 – 45 ℃ |
| pH Range (Continuous Operation) | 2.0 – 11.0 |
| Maximum Feed TDS | 5000 ppm |
| Feed Water SDI Requirement | ≤3 |
Core Advantages
Low Energy ConsumptionWorks under ultra-low operating pressure, reduces high-pressure pump power demand, greatly cutting electricity expenditure for long-time running small commercial water systems. It is an ideal upgrade choice to replace traditional low-pressure RO membranes.
Balanced Flux & Salt RejectionCombines stable high salt rejection and satisfactory permeate output. The optimized membrane surface avoids excessive flux that easily triggers membrane fouling, balancing productivity and service life.
Compact 4021 Size, Wide Compatibility4021 dimension is perfectly suited for small, space-limited RO skids. It can directly replace equivalent imported 4021 membrane elements, no modification needed for existing membrane housings.
Enhanced Anti-fouling Surface PropertyModified hydrophilic membrane surface reduces the adhesion of organic matter and colloids. The frequency of CIP chemical cleaning is decreased, saving chemical agent cost and system downtime.
Cost-effective Replacement SolutionCompared with famous imported membrane brands, our ULP31-4021 delivers comparable filtration performance at a competitive price, supporting EPC contractors and water treatment distributors to control project budget.
Application Scenarios
Small commercial well water desalination
Municipal tap water deep purification for drinking water
Small factory pure water production for food & beverage, electroplating auxiliary water
Portable compact RO water treatment skids
Water reuse pre-treatment for light industrial wastewater
FAQ
Q1: What raw water is suitable for ULP31-4021 RO membrane?
A1: It is mainly designed for brackish water, well water and municipal tap water with feed TDS below 5000ppm. It is not recommended for high-salinity seawater without special configuration.
Q2: Can ULP31-4021 directly replace imported 4021 RO membrane?
A2: Yes. The physical dimension and connection interface are fully consistent with standard 4021 membrane elements, direct drop-in replacement is available.
Q3: What pretreatment is required before this RO membrane?
A3: Feed water should be pretreated to ensure SDI ≤3. Liquid Filters and Self Cleaning Filter are commonly used as pretreatment units to protect RO membrane from particulate contamination.
Q4: What is the expected service life of ULP31-4021?
A4: Under qualified pretreatment and standard operation, the normal service life can reach 2–3 years. Poor feed water quality will shorten membrane lifespan.
Q5: How to clean the ULP31-4021 membrane when fouling occurs?
A5: Conduct CIP chemical cleaning according to pollutant types, acidic cleaning for inorganic scaling and alkaline cleaning for organic fouling.
Related Products
Anti‑Fouling RO Membrane for Wastewater Reuse Treatment
High Salt Rejection RO Membrane for Brackish Water Treatment
Custom Reverse Osmosis Membrane for Water Treatment Solution
Low Pressure RO Membrane for Commercial Water Treatment Unit
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