For the successful operation of a reverse-osmosis freshwater generator, the setting of the brine back pressure regulator is critical. What statement regarding the set point of this regulator is true?

Correct Answer: Option A — If the regulator setting is set too high, the membrane modules may be damaged. If the regulator setting is too low, the freshwater production will be too low.

Excessive pressure from a high regulator setting can physically rupture or compact the membrane modules, causing permanent damage. Conversely, if the pressure is too low, the system fails to overcome osmotic pressure, resulting in insufficient freshwater production as the permeate flux through the membrane significantly decreases.