A CFD model incorporating flotation kinetic expressions is developed to simulate the performance of flotation tanks utilized in water and wastewater treatment plants. The focus here is on tanks that operate without any external means of flow mixing (impeller, etc.), such as Dissolved Air Flotation (DAF) tanks, where bubble buoyancy, particle settling, and turbulence are mechanisms contributing comparably to local flotation rates. These flotation mechanisms are analyzed, and the variation of their relative contribution with respect to basic parameters of the flotation process is examined. To increase the computation efficiency, realistic assumptions are made regarding the fluid dynamics and particle conservation issues of the model, and CFD simulations are performed in a two-dimensional frame of reference. Simulation results demonstrate the existence of a complex interaction between tank hydrodynamics and local flotation rates which lead to particle removal efficiencies that could never be invoked by flotation theories alone.