Oil and grease removal in preliminary treatment is accomplished by using?

Oil and grease removal in preliminary treatment is accomplished by using?

• A. Aeration tanks
• B. Biological treatment
• C. Chlorination
• D. Skimmers and coalescing plates are used

Answer: (D)

Oil and grease float on water, so early treatment focuses on pulling that slick out and speeding up the separation. Skimmers physically remove the floating oil from the surface, while coalescing plates in oil–water separators give oil droplets a place to combine into larger drops. When used together, they efficiently remove oil and grease before the wastewater moves on to downstream treatment. Aeration tanks are for introducing air to support biological oxidation, not oil removal; chlorination is for disinfection, not removing oil.

Oil and grease float on water, so early treatment focuses on pulling that slick out and speeding up the separation. Skimmers physically remove the floating oil from the surface, while coalescing plates in oil–water separators give oil droplets a place to combine into larger drops. When used together, they efficiently remove oil and grease before the wastewater moves on to downstream treatment. Aeration tanks are for introducing air to support biological oxidation, not oil removal; chlorination is for disinfection, not removing oil.