Development of a tool, using CFD, for the assessment of the disinfection process by ozonation in industrial scale drinking water treatment plants

Talvy, Samuel Lucien; Debaste, Frédéric; Martinelli, Laure; Chauveheid, Éric; Haut, Benoı̂t

doi:10.1016/j.ces.2011.02.039

Cited by 24 publications

(20 citation statements)

References 14 publications

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“…Hitherto, few methods enabling the producers to fully assess the capacity of a drinking water plant to inactivate resistant pathogenic microorganisms have been proposed. Some previous studies have proposed Computational Fluid Dynamics (CFD) tools to assess an ozonation step in a drinking water plant (Audenaert et al, 2010;Cockx et al, 1999;Talvy et al, 2011). These tools provide information such as the dynamics of the liquid and gas phases, the ozone concentration field in the disinfection step and the contact time between microorganisms and the disinfectant in the process.…”

Section: Introductionmentioning

confidence: 99%

“…The second goal of this paper is to assess the efficiency of an existing ozonation step to inactivate resistant pathogenic microorganisms similar to B. subtilis spores using the CFD tool proposed by Talvy et al (2011) and the lag time correlation established in this work. The studied process is the ozonation step of the Tailfer drinking water plant operated by Vivaqua (Belgium).…”

Section: Introductionmentioning

confidence: 99%

“…The studied process is the ozonation step of the Tailfer drinking water plant operated by Vivaqua (Belgium). From the CFD tool proposed and validated by Talvy et al (2011), the contact time distribution between microorganisms and the ozone in this step is determined. Evaluation of the Tailfer plant disinfection step efficiency is obtained by computing the fraction of the resistant microorganisms that are still in their lag phase at the exit of the step, and therefore that are not inactivated, using the lag time correlation and the contact time distribution of these microorganisms with the disinfectant in the step.…”

Section: Introductionmentioning

confidence: 99%

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Ozone inactivation of resistant microorganisms: Laboratory analysis and evaluation of the efficiency of plants

et al. 2012

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In this work, the ozone inactivation of resistant microorganisms is studied and a method to assess the efficiency of a drinking water plant to inactivate resistant microorganisms using ozone is proposed. This method aims at computing the fraction of resistant microorganisms that are not inactivated at the exit of an ozonation step by evaluating the duration of the lag phase of the ozone inactivation of these microorganisms and the contact time distribution of these microorganisms with the ozone in the step. To evaluate the duration of the lag phase of the ozone inactivation of resistant pathogenic microorganisms, an experimental procedure is proposed and applied to Bacillus subtilis spores. The procedure aims at characterizing the ozone inactivation kinetics of B. subtilis spores for different temperature and ozone concentration conditions. From experimental data, a model of the ozone inactivation of B. subtilis spores is built. One of the parameters of this model is called the lag time and it measures the duration of the lag phase of the ozone inactivation of B. subtilis spores. This lag time is identified for different temperature and ozone concentration conditions in order to establish a correlation between this lag time and the temperature and ozone concentration conditions. To evaluate the contact time distribution between microorganisms and the ozone in a disinfection step of a drinking water plant, a computational fluid dynamics tool is used. The proposed method is applied to the ozonation channel of an existing drinking water plant located in Belgium and operated by Vivaqua. Results show that lag times and contact times are both in the same order of magnitude of a few minutes. For a large range of temperatures and ozone concentrations in the Tailfer ozonation channel and for the highest hydraulic flow rate applied, a significant fraction of resistant microorganisms similar to B. subtilis spores is not inactivated.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Ozone inactivation of resistant microorganisms: Laboratory analysis and evaluation of the efficiency of plants

et al. 2012

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“…Many of these studies during the past two decades have used computational fluid dynamics (CFD) coupled with mass transfer. In the field of drinking water disinfection, Cockx et al (1999), Talvy et al (2011), and Gong et al (2007) have modeled the ozonation process to predict ozone dissolving. Laakkonen et al (2006a;2006b) have investigated mass transfer in agitated fermenter vessels considering local population balance distribution.…”

Section: Introductionmentioning

confidence: 99%

CFD analysis of laboratory scale phase equilibrium cell operation

Jama

Nikiforow

Qureshi

et al. 2017

Review of Scientific Instruments

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For the modeling of multiphase chemical reactors or separation processes, it is essential to predict accurately chemical equilibrium data, such as vapor-liquid or liquid-liquid equilibria [M. Šoóš et al., Chem. Eng. Process.: Process Intensif. 42(4), 273–284 (2003)]. The instruments used in these experiments are typically designed based on previous experiences, and their operation verified based on known equilibria of standard components. However, mass transfer limitations with different chemical systems may be very different, potentially falsifying the measured equilibrium compositions. In this work, computational fluid dynamics is utilized to design and analyze laboratory scale experimental gas-liquid equilibrium cell for the first time to augment the traditional analysis based on plug flow assumption. Two-phase dilutor cell, used for measuring limiting activity coefficients at infinite dilution, is used as a test case for the analysis. The Lagrangian discrete model is used to track each bubble and to study the residence time distribution of the carrier gas bubbles in the dilutor cell. This analysis is necessary to assess whether the gas leaving the cell is in equilibrium with the liquid, as required in traditional analysis of such apparatus. Mass transfer for six different bio-oil compounds is calculated to determine the approach equilibrium concentration. Also, residence times assuming plug flow and ideal mixing are used as reference cases to evaluate the influence of mixing on the approach to equilibrium in the dilutor. Results show that the model can be used to predict the dilutor operating conditions for which each of the studied gas-liquid systems reaches equilibrium.

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“…Despite this, most of the works [6] use the well-known model. In the work of Talvy et al [7] a numerical modelling of a full scale oxidation ditch is carried out, simulating the mixer impellers as plane regions with a pressure jump between both sides of the planes.…”

Section: Introductionmentioning

confidence: 99%

Effects of the aeration on the fluid dynamic behaviour of a multi-zone activated sludge system

Sánchez

Kaiser

Viedma

et al. 2016

WIT Transactions on Ecology and the Environment

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Conventional wastewater treatment plants (WWTP) are necessary to modify the wastewater properties in order to make it acceptable for a safe discharge into the environment or a certain reuse purpose. Biological oxidation is the most important of the processes involved in conventional WWTP. Organic substances dissolved in the water are removed by means of bacteria presented in the biological reactor. Air is necessary to enable the reduction of the organic content of the water by the bacteria. Bubbles of air are introduced into the reactor through air diffusers. Air diffusers can account up to 70% of WWTP total energy consumption.So a deep understanding of the dynamic behaviour of the flow is necessary for optimizing the process and saving energy.A numerical analysis of the effects of the aeration in the fluid dynamics behaviour of a real multi-zone activated sludge reactor is carried out. The purpose is to identify and analyse the changes originated in the velocity field by the aeration.A numerical modelling of the activated sludge system located in San Pedro del Pinatar (Murcia, Spain) is developed throughout a general-purpose computational fluid dynamics (CFD) code. The multiphase flow is simulated with a EulerLagrange approach; modelling the bubbles as discrete phase. Two simulations, one with aeration and the other without it, are carried out. The numerical results show that the aeration has a notable effect in the performance of the reactor. Changes in velocity field, stagnant zones, residence time distribution or even free surface level originated by the aeration in the reactor are studied. In general, the aeration reduced the amount of stagnant volume in the reactor. However, when the aeration is activated, some re-circulating zones are formed, reducing the residence time in the reactor.

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Development of a tool, using CFD, for the assessment of the disinfection process by ozonation in industrial scale drinking water treatment plants

Cited by 24 publications

References 14 publications

Ozone inactivation of resistant microorganisms: Laboratory analysis and evaluation of the efficiency of plants

Ozone inactivation of resistant microorganisms: Laboratory analysis and evaluation of the efficiency of plants

CFD analysis of laboratory scale phase equilibrium cell operation

Effects of the aeration on the fluid dynamic behaviour of a multi-zone activated sludge system

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