The development and application of CFD models for water treatment flocculators

The use of CFD to simulate turbulent flows in laboratory and full scale flocculation processes commonly found at water treatment works is reported. The paper considers a range of modelling strategies and simulation techniques including, inter alia, steady and unsteady flow, two-equation and Reynolds stress turbulence modelling, sliding mesh and multiple reference frames approaches to rotational flow simulation, and mesh density optimisation. Through analysis of turbulence dissipation rate, this work considers the development of models for environmental engineering problem solving and demonstrates clearly the benefits to be gained from the use of CFD in flocculation vessels.

[1]  Herve Morvan.  Automating CFD for non-experts , 2005 .

[2]  Stefan Blaser,et al.  Particles under stress , 1998 .

[3]  E. Lainé,et al.  Using CFD in the Study of Mixing in Coagulation and Flocculation , 2000 .

[4]  Ivan Fort,et al.  Velocity profiles in a closed, unbaffled vessel: comparison between experimental LDV data and numerical CFD predictions , 1997 .

[5]  Joel J. Ducoste,et al.  Simulation of Flocculation in Stirred Vessels Lagrangian Versus Eulerian , 2007 .

[6]  W Gujer,et al.  Activated sludge modelling: past, present and future. , 2006, Water science and technology : a journal of the International Association on Water Pollution Research.

[7]  P. Roache.  Verification of Codes and Calculations , 1998 .

[8]  C. Luo,et al.  Distribution of velocities and velocity gradients in mixing and flocculation vessels : comparison between LDV data and CFD predictions , 1997 .

[9]  J. Haarhoff,et al.  Towards optimal design parameters for around-the-end hydraulic flocculators , 2001 .

[10]  B Jefferson,et al.  A review of floc strength and breakage. , 2005, Water research.

[11]  J. Gregory.  The density of particle aggregates , 1997 .

[12]  David G. Thomas.  Turbulent disruption of flocs in small particle size suspensions , 1964 .

[13]  John Bridgeman,et al.  Assessing floc strength using CFD to improve organics removal , 2008 .

[14]  Paul Lant,et al.  Activated sludge flocculation: on-line determination of floc size and the effect of shear , 2000 .

[15]  B. Jefferson,et al.  The duplicity of floc strength. , 2004, Water science and technology : a journal of the International Association on Water Pollution Research.

[16]  J. Haarhoff,et al.  Design of around‐the‐end hydraulic flocculators , 1998 .

[17]  D. W. Smith,et al.  Measurement of Turbulent Flow in Standard Jar Test Apparatus , 1995 .

[18]  Li Xiao-yan,et al.  Modelling the kinetics of aggregate breakage using improved breakage kernel. , 2008, Water science and technology : a journal of the International Association on Water Pollution Research.

[19]  Ingmar Nopens.  Improved prediction of effluent supended solids in clarifiers through integration of a population balance model and a CFD model , 2007 .

[20]  Hoi Yeung,et al.  Modelling of service reservoirs , 2001 .

[21]  Alain Liné,et al.  Flocculation related to local hydrodynamics in a Taylor–Couette reactor and in a jar , 2005 .

[22]  Pelton,et al.  Micromechanics: A New Approach to Studying the Strength and Breakup of Flocs , 1996, Journal of colloid and interface science.

[23]  Weeratunge Malalasekera,et al.  An introduction to computational fluid dynamics - the finite volume method , 2007 .