When the oily-water separator, shown in the illustration, is in operation and processing clear bilge water, what should be the internal water level? Illustration GS-0153

Correct Answer: Option C — The water level should be located in the upper section of the tank.

Oily-water separators operate by gravity separation, where oil floats to the top. Maintaining the water level in the upper section of the tank ensures that the coalescer beds remain fully submerged, allowing the oil to accumulate at the top for subsequent discharge through the oil outlet valve.