What aids in increasing the efficiency of oil/water separators?

• A. Filtration Membranes
• B. Coalescing Units
• C. Heat Exchangers
• D. Activated Sludge

Answer: (B)

Promoting coalescence of dispersed oil droplets is the main idea behind increasing efficiency in oil/water separation. When oil is finely dispersed in water, many tiny droplets resist quick separation because their interfacial films and surfactants keep them from merging. Coalescing units provide surfaces and flow conditions that encourage droplets to collide and merge into larger droplets. As droplets grow, their buoyancy increases and they rise to the surface faster, allowing easier skimming and removal of the oil. This makes the separation process quicker and more complete, especially for free or lightly emulsified oil.

Filtration membranes mainly target solid particulates and can foul when faced with oil emulsions, so they’re not the best fit for enhancing the separation of free oil from water. Heat exchangers move heat between streams and don’t fundamentally improve oil droplet separation. Activated sludge is a biological treatment process that degrades organic matter, not a mechanism for separating oil from water.