Manufacturers publish maximum membrane flow rate under laboratory conditions: distilled water at 25°C and ideal pressure. In the field, real output is 40–60% of the nominal value.
We size each plant using the actual conductivity, temperature and TDS of your water source. The output we quote is what you get in the field, not in a lab.
What TDS was used to calculate the flow rate?
The higher the salinity of the water, the lower the output. Require that the quote specify the TDS or conductivity of the source used in the calculation.
What is the actual working pressure?
The pump must maintain the required pressure with the real feed flow rate. Ask for the pump model, its HP and the pressure curve.
What is the recovery rate?
A real plant recovers 40–50% of the feed water. Real example: 3 × ULP-4040 membranes at 150 PSI produce 18–24 L/min of treated water (6–8 L/min per membrane) with 39–48 L/min of total inlet.
Does it include complete pre-treatment?
Without proper sediment filter, activated carbon and antiscalant, membranes are damaged in months. Pre-treatment is not optional.
How long does the conversion rate last?
It depends on plant maintenance and the quality of the source water. Without adequate maintenance and proper pre-treatment, output drops progressively due to membrane fouling.
Want a quote that is
technically honest?
We calculate the real flow rate using your water, not lab data.
Membrane Rejection
| Cation | Symbol | % Rejection |
|---|---|---|
| Sodium | Na⁺ | 94–96 |
| Calcium | Ca²⁺ | 96–98 |
| Magnesium | Mg²⁺ | 96–98 |
| Potassium | K⁺ | 94–96 |
| Iron | Fe²⁺ | 98–99 |
| Manganese | Mn²⁺ | 98–99 |
| Aluminum | Al³⁺ | 99+ |
| Ammonium | NH₄⁺ | 88–95 |
| Copper | Cu²⁺ | 96–99 |
| Nickel | Ni²⁺ | 97–99 |
| Strontium | Sr²⁺ | 96–99 |
| Cadmium | Cd²⁺ | 95–98 |
| Silver | Ag⁺ | 94–96 |
| Arsenic | As³⁺ | 90–95 |
| Anion | Symbol | % Rejection |
|---|---|---|
| Chloride | Cl⁻ | 94–95 |
| Bicarbonate | HCO₃⁻ | 95–96 |
| Sulfate | SO₄²⁻ | 99+ |
| Nitrate | NO₃⁻ | 93–96 |
| Fluoride | F⁻ | 94–96 |
| Silicate | SiO₂⁻ | 95–97 |
| Phosphate | PO₄³⁻ | 99+ |
| Bromide | Br⁻ | 94–96 |
| Borate | B₄O₇²⁻ | 35–70 ** |
| Chromate | CrO₄²⁻ | 90–98 |
| Cyanide | CN⁻ | 90–95 ** |
| Sulfite | SO₃²⁻ | 98–99 |
| Thiosulfate | S₂O₃²⁻ | 99+ |
| Ferrocyanide | Fe(CN)₆⁴⁻ | 99+ |
| Compound | Molecular weight | % Rejection |
|---|---|---|
| Sucrose | 342 | 100 |
| Lactose | 360 | 100 |
| Proteins | > 10,000 | 100 |
| Glucose | 198 | 99.9 |
| Phenol | 94 | 93–99 ** |
| Acetic acid | 60 | 65–70 |
| Dyes | 400–900 | 100 |
| Biochemical Oxygen Demand (BOD) | — | 90–99 |
| Chemical Oxygen Demand (COD) | — | 80–95 |
| Urea | 60 | 40–60 |
| Bacteria and viruses | 5,000–100,000 | 100 |
| Pyrogens | 1,000–5,000 | 100 |