Contact Tank Design Impact on Process Performance

Angeloudis, Athanasios; Stoesser, Thorsten; Gualtieri, Carlo; Falconer, Roger Alexander

doi:10.1007/s10666-016-9502-x

Cited by 30 publications

(21 citation statements)

References 28 publications

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“…This suggested that the best value for the Sc t could be related to the characteristics of the flow field in a contact tank [53]. More recently, Angeloudis et al [26][27][28][29] used Sc t = 0.7 to study the effect of tank geometry on the disinfection efficiency confirming the key role of this parameter in the reliable prediction of the tracer transport in a contact tank. The same value was adopted by Martínez-Solano et al [54] to study flow and concentration fields in a rectangular water tank [32].…”

Section: Water Systemsmentioning

confidence: 96%

“…A number of studies about the turbulent Schmidt number have dealt with the simulation of flow and tracer transport in open channels [22][23][24][25], while others have addressed those issues in contact or water tanks [26][27][28][29][30][31][32][33][34][35][36], inclined negatively-buoyant discharges [37], sediment-laden open channel flows [38][39][40][41][42][43][44][45][46][47][48], density stratified turbulence [49,50] and T-junction mixing experiments [51] ( Table 2). The terms "Exp" and "Num" mean the application of experimental and numerical methods, respectively, in each study.…”

Section: Water Systemsmentioning

confidence: 99%

“…Arnold et al [22] Flow and tracer transport in open channels Exp − Sc t = 0.5-0.9 Djordjevic [23] Flow and tracer transport in open channels Exp/Num − Sc t = 1 Lin and Shiono [24] Flow and tracer transport in open channels Exp/Num − Sc t = 0.72 Simões and Wang [25] Flow and tracer transport in open channels Exp/Num − Sc t = 0.5 (horizontal), 1 (vertical) Gualtieri [30] Flow and tracer transport in a contact tank Exp/Num − Sc t = 1 Rauen et al [33] Flow and tracer transport in a contact tank Exp/Num − Sc t = 1 Kim et al [31] Flow and tracer transport in a contact tank Exp/Num − Sc t = 0.3 Zhang et al [34][35][36] Flow and tracer transport in a contact tank Exp/Num − Sc t = 0.7 Angeloudis et al [26][27][28][29] Flow and tracer transport in a contact tank Exp/Num − Sc t = 0.7 Martínez-Solano et al [32] Flow and tracer transport in a water tank Exp/Num − Sc t = 0.7 Oliver et al [37] Inclined negatively buoyant discharges Exp/Num − Sc t = 0.6 Graf and Cellino [41] Sediment-laden open channel flows Exp − Sc t > 1 (no bedforms), Sc t < 1 (bedforms) Hsu and Liu [42] Sediment-laden open channel flows Exp/Num − Sc t = 0.7 Amoudry et al [39] Sediment-laden open channel flows Exp/Num − Sc t = 0.7 (bed), Sc t = 0.52 (surface)…”

Section: Referencementioning

confidence: 99%

See 2 more Smart Citations

On the Values for the Turbulent Schmidt Number in Environmental Flows

Gualtieri

Angeloudis

Bombardelli

et al. 2017

Fluids

Self Cite

166

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Computational Fluid Dynamics (CFD) has consolidated as a tool to provide understanding and quantitative information regarding many complex environmental flows. The accuracy and reliability of CFD modelling results oftentimes come under scrutiny because of issues in the implementation of and input data for those simulations. Regarding the input data, if an approach based on the Reynolds-Averaged Navier-Stokes (RANS) equations is applied, the turbulent scalar fluxes are generally estimated by assuming the standard gradient diffusion hypothesis (SGDH), which requires the definition of the turbulent Schmidt number, Sc t (the ratio of momentum diffusivity to mass diffusivity in the turbulent flow). However, no universally-accepted values of this parameter have been established or, more importantly, methodologies for its computation have been provided. This paper firstly presents a review of previous studies about Sc t in environmental flows, involving both water and air systems. Secondly, three case studies are presented where the key role of a correct parameterization of the turbulent Schmidt number is pointed out. These include: (1) transverse mixing in a shallow water flow; (2) tracer transport in a contact tank; and (3) sediment transport in suspension. An overall picture on the use of the Schmidt number in CFD emerges from the paper.

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Section: Water Systemsmentioning

confidence: 96%

Section: Water Systemsmentioning

confidence: 99%

Section: Referencementioning

confidence: 99%

See 1 more Smart Citation

On the Values for the Turbulent Schmidt Number in Environmental Flows

Gualtieri

Angeloudis

Bombardelli

et al. 2017

Fluids

Self Cite

166

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show abstract

“…Three-dimensional numerical simulations were conducted by Zachary et al [2] in order to maximize the disinfection efficiency of the contactor by modifying the hydraulic design of baffles. Guiding walls were included in the contact tank in order to minimize the recirculation effects [3]. The relationship between the baffling performance and energy loss for the definition of "hydraulic efficiency" of the contact tank system was investigated by Zhang et al [4], where the authors stated that the energy saving afforded by using more baffles in the contactor was offset by the extra energy necessary to drive the flow through the contact tank system.…”

Section: Introductionmentioning

confidence: 99%

Unified Analysis of Multi-Chamber Contact Tanks and Mixing Efficiency Based on Vorticity Field. Part I: Hydrodynamic Analysis

Demirel

Aral

2016

Water

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Multi-chamber contact tanks have been extensively used in industry for water treatment to provide potable water to communities, which is essential for human health. To evaluate the efficiency of this treatment process, flow and tracer transport analysis have been used in the literature using Reynolds averaged Navier-Stokes (RANS) and large-eddy simulations (LES). The purpose of this study is two-fold. First a unifying analysis of the flow field is presented and similarities and differences in the numerical results that were reported in the literature are discussed. Second, the vorticity field is identified as the key parameter to use in separating the mean flow (jet zone) and the recirculating zones. Based on the concepts of vorticity gradient and flexion product, it is demonstrated that the separation of the recirculation zone and the jet zone, fluid-fluid flow separation, is possible. The separation of the recirculation zones and vortex core lines are characterized using the definition of the Lamb vector. The separated regions are used to characterize the mixing efficiency in the chambers of the contact tank. This analysis indicates that the recirculation zone and jet zone formation are three-dimensional and require simulations over a long period of time to reach stability. It is recognized that the characteristics of the jet zones and the recirculation zones are distinct for each chamber and they follow a particular pattern and symmetry between the alternating chambers. Hydraulic efficiency coefficients calculated for each chamber show that the chambers having an inlet adjacent to the free surface may be designed to have larger volumes than the chambers having wall bounded inlets to improve the efficiency of the contact tank. This is a simple design alternative that would increase the efficiency of the system. Other observations made through the chamber analysis are also informative in redefining the characteristics of the efficiency of the contact tank system.

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“…were associated with carbohydrate utilization and selected enzymes showed different levels of inhibition by monochloramine when tested (Coburn et al, 2016). Angeloudis et al (2016) refined 3D numerical models to predict reactive processes in disinfection contact tanks with special emphasis on turbulent mixing and minimization of internal recirculation and short-circuiting. The results suggested that water treatment facilities can benefit from in-depth analyses of the flow and kinetic processes through computational fluid dynamics, resulting in up to 38 % more efficient pathogen inactivation and 14 % less disinfection byproducts (DBPs) formation.…”

mentioning

confidence: 99%