Eulerian modelling of the formation and flow of aggregates in dissolved air flotation
Paper in proceeding, 2012

Dissolved Air Flotation (DAF) is a well-established process within the drinking water treatment community. The process is driven by density differences caused by injection of air bubbles into the main water flow. Particulate matter in the water is flocculated into larger particles (termed flocs). The water, together with flocs, is thereafter mixed with the injected air bubbles. Buoyant aggregates are formed by adhesion of bubbles to the flocs. The aggregates rise to the surface of the unit where they are removed from the water phase. The objective of this paper is to conduct simulations of fluid dynamics of a DAF unit, with a specific aim to capture the formation and flow of aggregates. For that purpose, a model has been developed that explains the mechanisms that lead to creation of aggregates and results in estimation of their size. Details on the implementation of the aggregation model into an Eulerian framework are given in the paper. We show in the paper that the modelling framework can describe the dynamics of flotation by capturing the formation, change in size and movements of the aggregates through the contact zone of a pilot DAF unit as a function of the properties of the flocs.

Eulerian model

water treatment


aggregate model

air bubble

Dissolved Air Flotation (DAF)


Mia Bondelind

Chalmers, Civil and Environmental Engineering, Water Environment Technology

Henrik Ström

Chalmers, Applied Mechanics, Fluid Dynamics

Srdjan Sasic

Chalmers, Applied Mechanics, Fluid Dynamics

Lars Bergdahl

Chalmers, Civil and Environmental Engineering, Water Environment Technology

Proceedings of the conference on Modelling Fluid Flow, Budapest Hungary 2012

Vol. 2 650-657
978-963-08-4587-8 (ISBN)

Areas of Advance

Building Futures (2010-2018)

Subject Categories

Water Engineering

Fluid Mechanics and Acoustics


C3SE (Chalmers Centre for Computational Science and Engineering)



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