Question 120General Subjects - Assistant Engineer

The correct answer is A) Reverse osmosis unit. In a reverse osmosis (RO) unit, an air ejector is unnecessary because the RO process relies on applied pressure, not on the vacuum created by an air ejector, to force water through a semi-permeable membrane and remove dissolved salts and minerals. RO units do not require the air evacuation function that an air ejector provides in other types of fresh water generators, such as submerged tube, titanium plate, or flash type units. The other options (B, C, and D) all involve processes that utilize an air ejector to create a vacuum and facilitate the evaporation or distillation of seawater, making an air ejector a necessary component in those systems.