🔍 Key Concepts

• Behavior of pressure drop across RO membrane modules when they become fouled or scaled • Difference between issues in the membrane modules vs. issues in pre-treatment filters • Relationship between feed pressure, pressure drop, and flow rate in a reverse-osmosis system

💭 Think About

• When membranes foul or scale, what typically happens to the resistance to flow through them, and how does that affect pressure from inlet to outlet? • Which indication most directly points to a problem inside the membrane modules themselves rather than in upstream equipment? • Think about what would happen to product water output and required pump effort if the membranes are getting clogged over time.

✅ Before You Answer

• Identify which option refers specifically to across the membrane modules, not other parts of the system • Match the sign and size of the pressure drop change (too low vs. too high) with what you expect when flow passages are becoming restricted • Ensure you are not confusing a problem in the pre-treatment filter with a problem inside the RO membrane modules themselves