Flux - RO Membranes

Advanced Reverse Osmosis Technology

Flux or Water Flux - Typically expressed as volume per area per unit of time, flux is used to express the rate at which water permeates a membrane. Typical units are gallons per square foot per day (i.e. GFD or GSFD) or litres per square meter per hour (l/m2/hr). The flux of a membrane is directly proportional to temperature and pressure. As a rule of thumb, flux decreases 1.5% per 1oF. Salt flux is the amount of TDS passed through a given area of membrane per unit of time. It is important to remember that Salt flux is a function of concentration gradient and not driving pressure. Therefore with increasing driving pressure, the concentration of salts in the permeate decreases due to constant salt leakage (e.g., milligrams) and increased water flux (e.g., liters). The net effect of increased drive pressure is to dilute a constant amount of slat with more pure water.

Note: 1 GFD = 1.66 l/m2/hr

For further information or assistance please contact Reverse Osmosis Chemicals International on +44 (0) 161 877 2334 or e-mail info@rochemicals.com.