Modeling of the hydrodynamics and energy expenditure of oxidation ditch aerated with hydrojets using CFD codes

This work uses computational fluid dynamics (CFD) as a design tool in wastewater treatment modeling practice to assess the specific use of the hydrojets in oxidation ditches. The hydrodynamics and the residence time distribution in an oxidation ditch are simulated using several turbulence models: Reynolds averaged Navier–Stokes simulations (RANS) and unsteady RANS with the standard k ‒ e model; and large eddy simulation with the Smagorinsky subgrid scale model. The influence of the mesh resolution, of the hydrojets placement on the oxidation ditch hydrodynamics and on the energy demand for mixing is assessed. Finally, the effect of the turbulence models on the macromixing data, which can be implemented in the activated sludge model, is also evaluated.

[1]  Jyeshtharaj B. Joshi,et al.  Effect of nozzle diameter and its orientation on the flow pattern and plume dimensions in gas-liquid jet reactors , 2007 .

[2]  A. Shukhry.  Flow Around Bends in an Open Flume , 1950 .

[3]  Scott A. Wells,et al.  A general model of the activated sludge reactor with dispersive flow- I. Model development and parameter estimation , 2000 .

[4]  E. Schroeder,et al.  Density of activated sludge solids , 1991 .

[5]  Zhiqiang Wang,et al.  PDA experiments and CFD simulation of a lab-scale oxidation ditch with surface aerators , 2010 .

[6]  Y. L. Moullec,et al.  Comparison of systemic, compartmental and CFD modelling approaches: Application to the simulation of a biological reactor of wastewater treatment , 2010 .

[7]  J. R. West,et al.  Mixing studies in an orbal activated sludge system. , 2004 .

[8]  G. V. Straten,et al.  Effect of oxidation ditch horizontal velocity on the nitrogen removal process , 2002 .

[9]  Karel J. Keesman,et al.  Sensitivity analysis in oxidation ditch modelling: the effect of variations in stoichiometric, kinetic and operating parameters on the performance indices , 2001 .

[10]  Z. Do-Quang,et al.  Computational fluid dynamics applied to water and wastewater treatment facility modeling , 1998 .

[11]  C. Liu,et al.  A three dimensional k-ɛ-Ap model for water-sediment movement , 2010 .

[12]  Anna Maria Karpinska Portela,et al.  New Design Tools for Activated Sludge Process , 2014 .

[13]  Activated Sludge Models Coupled to CFD Simulations , 2012 .

[14]  C Printemps,et al.  Modelling of wastewater treatment plants--how far shall we go with sophisticated modelling tools? , 2005, Water science and technology : a journal of the International Association on Water Pollution Research.

[15]  J. A. Mueller,et al.  Aeration: principles and practice. , 2002 .

[16]  Sylvie Gillot,et al.  Effect of horizontal flow on oxygen transfer in clean water and in clean water with surfactants , 2000 .

[17]  J. Barnard,et al.  Density and activity characterization of activated sludge flocs , 2006 .

[18]  C. Fonade,et al.  Impact of agitation and aeration on hydraulics and oxygen transfer in an aeration ditch: Local and global measurements , 2007 .

[19]  Daijun Zhang,et al.  Simulation of Component Distributions in a Full-Scale Carrousel Oxidation Ditch: A Model Coupling Sludge-Wastewater Two-Phase Turbulent Hydrodynamics with Bioreaction Kinetics , 2010 .

[20]  Anastasios I. Stamou,et al.  Modelling of oxidation ditches using an open channel flow 1-D advection-dispersion equation and ASM1 process description , 1997 .

[21]  Y. L. Moullec,et al.  CFD simulation of the hydrodynamics and reactions in an activated sludge channel reactor of wastewater treatment , 2010 .

[22]  R. Townsend,et al.  3D Numerical Modeling of Flow and Sediment Transport in Laboratory Channel Bends , 2007 .

[23]  Yin Yang,et al.  Simulation of flow field and sludge settling in a full-scale oxidation ditch by using a two-phase flow CFD model , 2014 .

[24]  Anastasios I. Stamou,et al.  Improving the hydraulic efficiency of water process tanks using CFD models , 2008 .

[25]  Chris J. Brouckaert,et al.  The use of computational fluid dynamics for improving the design and operation of water and wastewater treatment plants , 1999 .

[26]  Z. Do-Quang,et al.  Global and local mass transfer coefficients in waste water treatment process by computational fluid dynamics , 2001 .

[27]  Colin D. Groff,et al.  Field and CFD Analysis of Jet Aeration and Mixing , 2012 .

[28]  Y. L. Moullec,et al.  Flow field and residence time distribution simulation of a cross-flow gas–liquid wastewater treatment reactor using CFD , 2008 .