Nominal rejection performance table below is extracted from Water Quality Association knowledge base for standard thin film composite reverse osmosis membranes operating at operating at a net pressure (feed pressure less back pressure and osmotic pressure) of 60 psi and 77°F water temperature. Performance of ro systems utilizing TFC membranes may be less due to changes in feed pressure, temperature, water chemistry, contaminant level, net pressure on membrane, and individual membrane efficiency. Tank-less RO systems (such as countertop ROs) and ROs with atmospheric tanks produce better overall rejection performance than undersink ROs (or ROs with pressure tanks) due to maximizing of net pressure on membrane.

Sodium 90-95%
Aluminum 93-98%
Magnesium 93-98%
Potassium 90-95%
Iron 93-98%
Manganese 93-98%
Calcium 93-98%
Copper 94-99%
Silver 93-98%
Zinc 93-98%
Strontium 93-98%
Cadmium 93-98%
Nickel 93-98%
Mercury 93-98%
Radioactivity 93-98%
Chromium-6 94-99%
Chromium-3 94-99%
Lead 94-99%
Chloride 90-95%
Bicarbonate 90-95%
Nitrate 85-90%
Fluoride 90-97%
Phosphate 93-98%
Chromate 90-95%
Cyanide 90-95%
Sulfate 93-98%
Boron 55-60%
Arsenic + 3 70-80%
Arsenic + 5 94-99%
Selenium 93-98%
Barium 93-98%
Sediment > 99%
Protozoa > 99%
Ameobic Cysts > 99%
Turbidity > 99%
Asbestos > 99%
Bacteria > 99%
Giardia > 99%
   
   
   

*     Source: water quality association, www.wqa.org

**   60 psi net pressure and 77° F water temperature

*** Performance depends on condition of feed water

WECO TDS Rejection Chart