Which technique is commonly used to remove oil from wastewater using air flotation?

• A. Skimming
• B. Filtration
• C. Flotation
• D. Emulsion Breaking

Answer: (C)

This technique relies on using air bubbles to lift oil droplets out of wastewater. Tiny air bubbles are introduced so oil droplets cling to them, forming buoyant bubble-droplet clusters that rise to the surface. The accumulated oil at the top can then be skimmed off, leaving cleaner water behind. This approach is particularly effective for emulsified oils that don’t separate well by gravity alone. Skimming alone only removes surface oil, and filtration targets solids and tends to foul when faced with oils; emulsion breaking is a chemical step to destabilize droplets and is not the separation method by itself.