They answer different questions
Recovery describes the proportion of feed flow collected as permeate. Salt rejection describes the reduction in a measured dissolved-solute concentration from feed to permeate. A high value for one does not establish the value of the other.
Keep the measurement boundary explicit
Recovery (%) = permeate flow ÷ feed flow × 100. Salt rejection (%) = (1 − permeate concentration ÷ feed concentration) × 100. The flows or concentrations must refer to a consistent boundary and sampling period. Conductivity-based field estimates should state the measurement method.
Compare conditions before comparing numbers
Manufacturer membrane test conditions and whole-system operating conditions are not interchangeable. Feed composition, temperature, pressure, recovery and pretreatment affect results. Higher recovery can increase concentrate loading and scaling risk; the appropriate target depends on the water and design.
What to send for a practical discussion
Provide the membrane model, arrangement, feed analysis, simultaneous feed/permeate/concentrate flows, pressure, temperature and relevant conductivity measurements. Avoid diagnosing a system from one percentage or combining element ratings into an assumed system guarantee.
Further Technical Reading
Manufacturer references for general background. These documents describe the respective manufacturer’s products and do not establish performance or certification for a different model.
OSMIVO technical resources · Updated 28 October 2026. General procurement guidance; confirm exact-model information against current manufacturer documentation.