Ozone‐contactor flow visualization and quantification using three‐dimensional laser‐induced fluorescence

O zonation for primary disinfection in drinking water treatment is typically carried out using a contactor consisting of multiple vertical or horizontal chambers connected in series. Ozone is fed by sidestream venturi injectors (SVI) or fine bubble diffusers (FBD) in upstream chambers, whereas downstream chambers provide the contact time required for pathogen inactivation. The SVI system is preferred when ozone is generated from pure oxygen because the gas flow rate is generally insufficient for bubble diffusers (Schulz et al, 1995). Also, the high-influent momentum results in efficient turbulent mixing at the injection point, providing more effective ozone transfer than the FBD process (Schulz & Bellamy, 2000). However, in the SVI process it is essential to carefully characterize and control the intense local mixing because of the ozone jet injection and/or influent injection through a narrow inlet pipe to the reactor. Occurrence of nonideal mixing conditions, such as short-circuiting (i.e., jet flowing preferentially toward the reactor exit with insufficient residence time), internal recirculation, or backmixing (i.e., mixing of reactor effluent with influent), might otherwise be possible because of local mixing, which could strongly reduce the overall efficiency of the disinfection process (Kim et al, 2007a; Kim et al, 2007b; Tang et al, 2005). Ozone contactor hydrodynamics can be evaluated by a conservative tracer test and analyzing the result with flow models, such as the axial dispersion reactor (ADR) model or the continuously stirred tank reactor (CSTR) in series model. These models are one-dimensional (i.e., they have a single fitting parameter); however the models are not capable of explaining complex, time-dependent, and three-dimensional flow behaviors that occur within the reactor. More sophistiDOOIL KIM,

[1]  Walter M. Grayman,et al.  Scale-Model Studies of Mixing in Drinking Water Storage Tanks , 1999 .

[2]  B. M. Khudenko,et al.  Hydrodynamic parameters of diffused air systems , 1986 .

[3]  Simon Lo,et al.  The Development Of An Ozone Contact Tank Simulation Model , 1995 .

[4]  Anthony D. Lucey,et al.  Reduction of Mixing in Jet-Fed Water Storage Tanks , 2004 .

[5]  David Henry,et al.  Finite Element Analysis And T10 Optimization Of Ozone Contactors , 1995 .

[6]  C. Teitelboim RADIATION REACTION AS A RETARDED SELF-INTERACTION. , 1971 .

[7]  Philip J. W. Roberts,et al.  Hydraulic model study for Boston outfall. II: Environmental performance , 1993 .

[8]  L. B. Garrett,et al.  Evaluating a high‐efficiency ozone injection contactor , 1995 .

[9]  이정호,et al.  Fundamentals of Fluid Mechanics, 6th Edition , 2009 .

[10]  William D. Bellamy,et al.  The Role of Mixing in Ozone Dissolution Systems , 2000 .

[11]  C J Brouckaert,et al.  A computational fluid dynamic and experimental study of an ozone contactor. , 2002, Water science and technology : a journal of the International Association on Water Pollution Research.

[12]  Benito Jose Marinas,et al.  Modeling Hydrodynamics and Ozone Residual Distribution in a Pilot‐Scale Ozone Bubble‐Diffuser Contactor , 1993 .

[13]  Jae-Hong Kim,et al.  Simultaneous simulation of pathogen inactivation and bromate formation in full‐scale ozone contactors by computer software , 2007 .

[14]  Joël Bertrand,et al.  Laser measurements of local velocity and concentration in a turbulent jet-stirred tubular reactor , 1991 .

[15]  Jacek Makinia,et al.  Evaluation of empirical formulae for estimation of the longitudinal dispersion in activated sludge reactors. , 2005, Water research.

[16]  E. Buckingham On Physically Similar Systems; Illustrations of the Use of Dimensional Equations , 1914 .

[17]  B. E. Drage,et al.  Development Of An Ozone Disinfection Contactor Using A Physical Scale Model , 1995 .

[18]  Philip J. W. Roberts,et al.  A 3D LIF system for turbulent buoyant jet flows , 2003 .

[19]  Jae-Hong Kim,et al.  Modeling Cryptosporidium parvum oocyst inactivation and bromate in a flow-through ozone contactor treating natural water. , 2007, Water research.

[20]  O. Levenspiel Chemical Reaction Engineering , 1972 .

[21]  Jae-Hong Kim,et al.  Modeling Cryptosporidium parvum oocyst inactivation and bromate formation in a full-scale ozone contactor. , 2005, Environmental science & technology.