Modelling the clogging of coarse gravel and tire shreds in column tests

Rowe, R. Kerry; Babcock, Dan BabcockD.

doi:10.1139/t07-057

Cited by 16 publications

(6 citation statements)

References 19 publications

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“…Four sub-models (Equations (10)-(13)) provide the needed parameters for Equation (9). Two mechanisms can be described using dispersion, namely molecular diffusion and mechanical dispersion [71]. In this model, only mechanical dispersion is respected (Equation 10),…”

Section: Clogging Due To Ssmentioning

confidence: 99%

The State of the Art of Clogging in Vertical Flow Wetlands

Pucher

Langergraber

2019

Water

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Clogging in vertical flow (VF) wetlands is an important process influencing water purification processes. The main contributing factors are the growth of microorganisms within the filter media, the accumulation of suspended solids on top of the wetland, as well as within the filter media. Both processes lead to a decrease of the available pore space, hence changing the soil’s hydraulic properties. This will alter the water flow and cause malfunctioning of the system. This paper summarizes the state of the art of the prevailing physical, biological and chemical processes influencing clogging in VF wetlands. Different design and operational parameters are discussed to give a better understanding on their influence to prevent malfunctioning. Based on a literature review, a detailed overview on experimental as well as modelling studies carried out is presented. The main conclusions are that on the one hand, important insights on clogging processes in VF wetlands have been gained but, on the other hand, design parameters such as intermittent loading operation and the grain size of the filter media are not well represented in those studies. Clogging models use different conceptual approaches ranging from black box models to process based models.

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Section: Clogging Due To Ssmentioning

confidence: 99%

The State of the Art of Clogging in Vertical Flow Wetlands

Pucher

Langergraber

2019

Water

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“…To show the effect of grain-size selection, modelling was also performed using a grain size of 21 mm. This size was found by Babcock (2005) and Rowe and Babcock (2007) to best represent an equivalent specific surface for the 38 mm gravel used by McIsaac (2007).…”

Section: Finite Element Mesh and Mediamentioning

confidence: 70%

“…Using the calibrated kinetic rates, the model was also applied to gravel-packed columns permeated with real leachate (Cooke et al 2005b) wherein the gravel porosity, as it changed over time, and the inorganic and organic clog quantities, at termination, were well predicted. Rowe and Babcock (2007) also used the model to examine clogging of coarse gravel and tire shreds in column experiments.…”

Section: Introductionmentioning

confidence: 99%

Modelling landfill leachate-induced clogging of field-scale test cells (mesocosms)

Cooke

Rowe

2008

Can. Geotech. J.

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A two-dimensional fluid flow and reactive transport model, BioClog, created to predict clogging in landfill leachate collection systems is used to calculate the clogging of gravel and treatment of leachate as it flows through the gravel in two real-scale experimental cells, called mesocosms, which represent the portion of a landfill drainage layer adjacent to a landfill collection pipe. These tests were conducted using real-time flows of landfill leachate and were run for about 6 and 12 years. The model computes spatial and temporal changes in clog quantity and composition. An empirical relationship predicts changes in hydraulic conductivity, and a variable mesh technique allows the surface to be free and dependent on calculated hydraulic heads. Calculated porosity change, effluent chemical oxygen demand (COD), and calcium concentrations, along with porosity and clog film thickness at termination are compared with the observed values and found to be in reasonable agreement given the variability and uncertainties associated with these processes. Résumé :Un écoulement fluide à deux dimensions et un modèle de transport réactif, BioClog, créé pour prédire le colmatage dans les systèmes de collecte de lixiviat d'enfouissement est utilisé pour calculer le colmatage de gravier et le traitement de lixiviat alors qu'il coule à travers le gravier dans deux cellules expérimentales à échelle réelle, appelées mésocosmes, qui représentent la portion de la couche de drainage de l'enfouissement adjacente aux tuyaux d'une collecte d'enfouissement. Ces essais ont été conduits en utilisant des écoulements à temps réel de lixiviat d'enfouissement et ont duré de 6 et 12 ans. Le modèle calcule les changements spatiaux et temporels dans la composition et la quantité de colmatage. Une relation empirique prédit les changements de la conductivité hydraulique, et une technique de grille variable permet d'obtenir une surface libre et dépendante des charges hydrauliques calculées. Le changement de porosité calculé, l'effluent de « chemical oxygen demand » (COD) et les concentrations de calcium, de même que la porosité et l'épaisseur du film de colmatage à la fin, sont comparés avec les valeurs observées, et on trouve qu'ils sont en concordance raisonnable compte tenu de la variabilité et des incertitudes associées avec ces procédés.Mots-clés : colmatage, enfouissements, systèmes de collecte de lixiviat, biofilms, précipitation de minéraux, drainage.[Traduit par la Rédaction]

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“…These questions include how clogging changes the device properties over time and how clogging depends on the geometry of the device. Although here we focus on biomedical devices, we remark that the issue of clogging pertains to a wide range of applications including water filtration, chemical extraction, soil rehabilitation using bacteria and traffic congestion [18][19][20].…”

Section: Introductionmentioning

confidence: 99%

Multi-scale model of clogging in microfluidic devices with grid-like geometries

Kelly

Fai

2022

Proc. R. Soc. A.

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We propose a coarse-grained theoretical model to capture the ageing of microfluidic devices under different conditions including constant applied flow rate and constant applied pressure gradient. Microfluidic devices that sort cells by their deformability hold significant promise for medical applications. However, clogging in these microfluidic systems causes their properties to change over time and potentially limits their reliability. We compare the results of the coarse-grained model with those of stochastic simulations and with existing theoretical studies. Lastly, we apply the model to experimental data on the clogging of sickle red blood cells and discuss its wider applicability.

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Modelling the clogging of coarse gravel and tire shreds in column tests

Cited by 16 publications

References 19 publications

The State of the Art of Clogging in Vertical Flow Wetlands

The State of the Art of Clogging in Vertical Flow Wetlands

Modelling landfill leachate-induced clogging of field-scale test cells (mesocosms)

Multi-scale model of clogging in microfluidic devices with grid-like geometries

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