Typical Rejection Characteristics of Thin Film Composite (TFC) Reverse Osmosis Membranes

Below are the typical rejection (removal) percentages of a standard thin film (TFC) reverse osmosis membrane. These are averages based on experience and are generally accepted within the industry. They are not a guarantee of performance. Actual rejection can vary according to the chemistry of the water, temperature, pressure, pH and other factors.


Estimated Reverse Osmosis Rejection Percentages

The reverse osmosis process uses a semi-permeable membrane to reject a wide variety of impurities. Here is a partial list.


Aluminum 97-98% Nickel 97-99%
Ammonium 85-95% Nitrate 93-96%
Arsenic 94-96% Phosphate 99+%
Bacteria 99+% Polyphosphate 98-99%
Bicarbonate 95-96% Potassium 92%
Boron 50-70% Pyrogen 99+%
Bromide 93-96% Radioactivity 95-98%
Cadmium 96-98% Radium 97%
Calcium 96-98% Selenium 97%
Chloride 94-95% Silica 85-90%
Chromate 90-98% Silicate 95-97%
Chromium 96-98% Silver 95-97%
Copper 97-99% Sodium 92-98%
Cyanide 90-95% Sulphate 99+%
Ferrocyanide 98-99% Sulphite 96-98%
Fluoride 94-96% Zinc 98-99%
Iron 98-99%
Lead 96-98% Insecticides 97%
Magnesium 96-98% Detergents 97%
Manganese 96-98% Herbicides 97%
Mercury 96-98% Virus 99+%
TDS (Total Dissolved Solids) 95-99% Hardness 93-97%

Figures given above are not actual test figures but are manufacturers’ estimates of normal TFC membrane performance