Coast Guard Exams
Question 105General Subjects - QMED70% to pass

What statement is true concerning the polishing coalescer filter of an oily-water separator?

AI Explanation
The correct answer is D. The coalescing filter of an oily-water separator is typically an oleophilic (oil-attracting) filter, meaning that small droplets of entrained oil in the oily-water mixture coalesce on the filter and form larger globules of oil that rise to the top of the filter housing. This allows the oil to be separated from the water and discharged overboard in compliance with environmental regulations. The other options are incorrect because a hydrophilic (water-attracting) filter would cause the water droplets to coalesce and sink, which is the opposite of what happens in an oily-water separator. Additionally, the oil globules rise to the top, not the bottom, of the filter housing.