Products Description
The Nanofiltration (NF) Membrane 500 GPD is designed for household and light commercial water treatment systems. It is suitable for applications where the goal is to reduce hardness, organic compounds, and other contaminants while retaining a portion of naturally occurring minerals in the treated water.
Compared with reverse osmosis (RO) membranes, an NF membrane has a lower salt rejection rate and selectively removes divalent and multivalent ions, such as calcium, magnesium, and sulfate, while allowing some monovalent ions to pass through. This makes it suitable for water treatment applications that require partial desalination rather than complete salt removal.
With a 500 GPD water production capacity, this membrane can be used in household water purifiers, under-sink filtration systems, office drinking water equipment, restaurants, cafés, and other light commercial systems. It operates at a lower pressure than most household RO membranes, which can reduce the operating pressure requirements of the system.
Product Specifications
| Membrane Element Type | Model |
(ft² / m²) |
Daily Water Production (GPD / m³/d) |
Stable Salt Rejection (%) |
Operating Pressure (PSI) |
|---|---|---|---|---|---|
| Household Nanofiltration Membrane Element | SLW--3013-500-(N) |
4.9 / 0.456 |
30~50 |
> 60 |
70 |
Standard Test Conditions
| Item | Test Condition |
|---|---|
| Feed Water Quality | 500 ppm (Sodium Chloride) |
| Test Temperature | 25 ± 5 ℃ |
| pH Range | 7.5 – 8 |
| Recovery Rate | 15 ± 5 % |
Maximum Operating Limits
| Item | Limit Condition |
|---|---|
| Maximum Operating Pressure | 300 PSI |
| Maximum Feed Water Temperature | 45 °C |
| Maximum Feed Water SDI (Silt Density Index) | ≤ 5 |
| Maximum Free Chlorine in Feed Water | < 0.1 ppm |
| Feed Water pH Range for Continuous Operation | 3 – 11 |
| Feed Water pH Range during Chemical Cleaning | 2 – 12 |
Membrane Element Dimensions
All dimensions shown are in millimeters (inches).
How Does a Nanofiltration (NF) Membrane Work?
A nanofiltration (NF) membrane is a kind of filter that uses water pressure to clean water. As water flows across the membrane, some things pass through, and some things get held back.
Water molecules and a few tiny particles, like certain salts, can go through the membrane. But bigger particles and salts with more than one charge-like calcium and magnesium-get trapped and are washed away with the leftover water.
Compared to ultrafiltration (UF), nanofiltration catches smaller particles. It can even remove some dissolved salts. But compared to reverse osmosis (RO), it doesn't remove as many salts. That means some natural minerals stay in the water, which is often a good thing.
Because it filters selectively like this, nanofiltration is often used for jobs like softening water, removing organic stuff, making water less colored, and treating drinking water when you don't need to remove all the salts.
NOTICE
When using a Nanofiltration (NF) Membrane 500 GPD, several important aspects should be considered to ensure stable performance and long service life.
First, feed water quality is critical. A Nanofiltration (NF) Membrane 500 GPD is generally suitable for low to moderate TDS water sources such as tap water, groundwater, and certain brackish waters. If the feed water has high turbidity, elevated iron or manganese levels, oil content, or high organic load, membrane fouling may occur easily. In such cases, proper pretreatment-such as PP cartridges, activated carbon filters, or iron and manganese removal units-is essential.
Second, operating pressure and recovery rate must be properly controlled. Although NF membranes operate at lower pressure than RO membranes, the system should still remain within the manufacturer's recommended range. Excessive pressure can accelerate membrane aging, while insufficient pressure may reduce permeate flow and salt rejection. Recovery rates should not be set too high, as this can increase the risk of scaling and flux decline.
Third, scaling and fouling risks require close attention. Since NF membranes have a high rejection rate for divalent and multivalent ions (such as Ca²⁺, Mg²⁺, and SO₄²⁻), scaling is more likely in high-hardness water conditions. The use of antiscalants or upstream softening may be necessary, and key indicators such as transmembrane pressure and permeate quality should be monitored regularly.
Fourth, residual chlorine and oxidant control is essential. Most NF membranes are made of polyamide material and are sensitive to chlorine, ozone, and other strong oxidants. Feed water chlorine levels should be strictly controlled, and activated carbon or other dechlorination measures are recommended to prevent irreversible damage to the Nanofiltration (NF) Membrane 500 GPD.
Fifth, routine cleaning and maintenance should not be overlooked. When permeate flow decreases significantly, operating pressure rises, or water quality becomes unstable, timely chemical cleaning (CIP) is required. Cleaning procedures and chemicals should be selected according to the type of fouling, such as organic fouling, biofouling, or inorganic scaling.
Finally, application matching and expectation management are important. A Nanofiltration (NF) Membrane 500 GPD is not designed for complete desalination. Its core advantage lies in selectively removing contaminants while retaining beneficial minerals. During system design and membrane selection, the treatment objectives-such as water softening, taste improvement, or selective ion removal-should be clearly defined rather than directly comparing its performance with that of reverse osmosis membranes.
With proper water quality assessment, system design, and operational management, nanofiltration membranes can deliver long-term, stable, and cost-effective performance in household and light commercial applications.
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