What is the primary benefit of using dissolved air flotation in wastewater treatment?

The primary benefit of using dissolved air flotation (DAF) in wastewater treatment is its effectiveness in separating emulsified oils from water. DAF systems operate by introducing air into the wastewater under pressure, which forms tiny air bubbles. These bubbles attach themselves to the suspended particles, including oil droplets, causing them to float to the surface. This floating mass can then be removed easily as a froth or scum.

The capability of DAF to efficiently separate emulsified oils is notably beneficial in industries where oil is a contaminant, such as food processing and petrochemical operations. This process contributes to the overall treatment efficiency by reducing chemical oxygen demand (COD) and improving the clarity of the treated effluent.

In contrast, the other options focus on different aspects of wastewater treatment. Promoting biological growth is more associated with biological treatment processes like activated sludge systems. The removal of heavy metals typically involves chemical precipitation or adsorption rather than flotation. Enhancing nutrient removal is often addressed through biological nutrient removal processes rather than solely through flotation technology. Therefore, the correct answer highlights the unique ability of DAF systems to effectively handle emulsified oils, which sets it apart from other wastewater treatment methods.