Reverse osmosis membranes need cleaning if the pressure drop through the unit increases by what percent?

Reverse osmosis membranes need cleaning if the pressure drop through the unit increases by what percent?

• A. 25%
• B. 10%
• C. 20%
• D. 15%

Answer: (C)

When a reverse osmosis membrane fouls, its flow resistance increases, so the differential pressure across the membrane climbs. Cleaning is scheduled when that pressure drop rises to a set threshold, serving to restore permeability before fouling causes irreversible damage. A 20% increase in differential pressure from the clean baseline is the commonly used rule of thumb. It provides a balance: cleaning too early wastes chemicals and time, while waiting longer lets fouling worsen and permeate flow decline. So the unit is typically cleaned when the pressure drop has increased by about 20%.

When a reverse osmosis membrane fouls, its flow resistance increases, so the differential pressure across the membrane climbs. Cleaning is scheduled when that pressure drop rises to a set threshold, serving to restore permeability before fouling causes irreversible damage. A 20% increase in differential pressure from the clean baseline is the commonly used rule of thumb. It provides a balance: cleaning too early wastes chemicals and time, while waiting longer lets fouling worsen and permeate flow decline. So the unit is typically cleaned when the pressure drop has increased by about 20%.