Modeling Physicochemical Processes of Microbial Transport in Porous Media

Persistent Link:
http://hdl.handle.net/10150/195468
Title:
Modeling Physicochemical Processes of Microbial Transport in Porous Media
Author:
Cheng, Li
Issue Date:
2006
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
The traditional colloid filtration model has been recognized to not fully describe transport of microorganisms in porous media under many conditions. Potential reasons for the discrepancies between colloid filtration theories and observed data are summarized into three aspects in the dissertation, including physicochemical heterogeneity, a blocking effect in the attachment process, and irreversible straining. A new transport model is developed to incorporate these non-ideal phenomena. First, both the collision-efficiency coefficient and the detachment-rate coefficient are formulated as probability density functions with log-normal distributions to represent physicochemical heterogeneity of both microbial and porous-medium grain surfaces. Second, the blocking effect is represented by appending a modified random sequential adsorption (RSA) function to the kinetic rate equation. Third, a semi-empirical equation is developed to describe the straining effect.The new model is then evaluated with a series of sensitivity analyses and illustrative applications to measured data. Sensitivity analysis on the role of probability density function (PDF) in collision efficiency and detachment rate coefficient shows that heterogeneity causes longer tailing in breakthrough curves, This effect is controlled by the implementation of the PDF in the detachment rate coefficient because the lower values among a series of detachment rate coefficients delay detachment. Straining phenonmena have received more and more attentions for protozoa transport. The new semi-empirical straining equation derived in the dissertation provides reasonable matches to the colloid data and cryptosporidium data. The Blocking effect is another process of concern for microbial transport, as shown in the analysis of microsporidium column experiments herein. The new model also proved to be successful for simulating MS-2 virus transport. The work presented will help enhance our understanding of biocolloid transport in porous media.
Type:
text; Electronic Dissertation
Keywords:
transport; microbial
Degree Name:
PhD
Degree Level:
doctoral
Degree Program:
Hydrology; Graduate College
Degree Grantor:
University of Arizona
Advisor:
Brusseau, Mark
Committee Chair:
Brusseau, Mark

Full metadata record

DC FieldValue Language
dc.language.isoENen_US
dc.titleModeling Physicochemical Processes of Microbial Transport in Porous Mediaen_US
dc.creatorCheng, Lien_US
dc.contributor.authorCheng, Lien_US
dc.date.issued2006en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractThe traditional colloid filtration model has been recognized to not fully describe transport of microorganisms in porous media under many conditions. Potential reasons for the discrepancies between colloid filtration theories and observed data are summarized into three aspects in the dissertation, including physicochemical heterogeneity, a blocking effect in the attachment process, and irreversible straining. A new transport model is developed to incorporate these non-ideal phenomena. First, both the collision-efficiency coefficient and the detachment-rate coefficient are formulated as probability density functions with log-normal distributions to represent physicochemical heterogeneity of both microbial and porous-medium grain surfaces. Second, the blocking effect is represented by appending a modified random sequential adsorption (RSA) function to the kinetic rate equation. Third, a semi-empirical equation is developed to describe the straining effect.The new model is then evaluated with a series of sensitivity analyses and illustrative applications to measured data. Sensitivity analysis on the role of probability density function (PDF) in collision efficiency and detachment rate coefficient shows that heterogeneity causes longer tailing in breakthrough curves, This effect is controlled by the implementation of the PDF in the detachment rate coefficient because the lower values among a series of detachment rate coefficients delay detachment. Straining phenonmena have received more and more attentions for protozoa transport. The new semi-empirical straining equation derived in the dissertation provides reasonable matches to the colloid data and cryptosporidium data. The Blocking effect is another process of concern for microbial transport, as shown in the analysis of microsporidium column experiments herein. The new model also proved to be successful for simulating MS-2 virus transport. The work presented will help enhance our understanding of biocolloid transport in porous media.en_US
dc.typetexten_US
dc.typeElectronic Dissertationen_US
dc.subjecttransporten_US
dc.subjectmicrobialen_US
thesis.degree.namePhDen_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineHydrologyen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorBrusseau, Marken_US
dc.contributor.chairBrusseau, Marken_US
dc.contributor.committeememberYeh, T.-C.en_US
dc.contributor.committeememberMeixner, Thomasen_US
dc.contributor.committeememberWarrick, Arthur W.en_US
dc.identifier.proquest1649en_US
dc.identifier.oclc659746278en_US
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