If a reverse-osmosis freshwater generator has fouled membrane modules, what statement is true?

Correct Answer: Option C — The freshwater production rate would be lower than normal, and the feed pressure would be higher than normal.

Fouling increases the resistance to flow across the membrane surface. To maintain a constant feed flow, the high-pressure pump must work harder, resulting in higher feed pressure. Simultaneously, the blocked membrane surface area reduces the permeate flux, leading to a lower freshwater production rate compared to clean operating conditions.