DAFscheiding

DAFscheiding, in Dutch often referred to as DAF-scheiding, is a water treatment process used to remove suspended solids, fats, oils, and colloidal particles from liquids. It operates on the principle of dissolved air flotation: air is dissolved in water under pressure, and when the water is released to atmospheric pressure, the dissolved air forms microbubbles that attach to particulates. The buoyant particles rise to the surface as a scum, which is then removed, producing clarified effluent.

The typical setup includes a saturator or recycle loop to dissolve air, a flotation tank where microbubbles form and attach to the flocs, and a skimmer or scraper to remove the floating sludge. Optional components include dosing systems for coagulants and flocculants to enhance aggregation, as well as sludge handling equipment. The clarified water exits from the bottom portion of the tank, while the collected float is periodically skimmed off.

DAFscheiding is widely used in municipal and industrial settings. It is effective for removing low-density solids, emulsified fats and oils, and fine particulate matter that are difficult to settle in conventional clarifiers. Common applications include municipal wastewater treatment, meat and dairy processing, food and beverage production, pulp and paper, and oil refinery effluents.

Advantages of DAFscheiding include high removal efficiency for colloids and fats, compact footprint, and flexibility to handle varying loadings. Limitations include energy consumption for pressurized air, chemical costs for optimizing flocculation, and sludge handling challenges for buoyant scum. Proper design and operation, including appropriate coagulant dosing and retention time, are essential for optimal performance.