The design of effective quality management strategies in groundwater systems is crucial, as clean water is essential for livelihood, health, and development. Colloids represent a class of contaminants that might be pathogenic or benign. Colloids can also enhance or inhibit the transport of dissolved contaminants in groundwater, which has inspired the use of benign colloids in the remediation of contaminated aquifers. Reliable modelling of colloid behavior is therefore essential for the design of effective remediation strategies, both those employing benign colloids and those aiming at the removal of pathogenic colloids. While colloid transport is controlled by groundwater velocity, colloid retention is governed by the physical and chemical properties of the aquifer together with those of the colloid. The present study aims at enhancing the reliability of modelling colloid behavior in fractured aquifers through: i) developing a synchronization-based framework that can effectively identify hydraulic connections within the aquifer; ii) developing a mathematical model for the relationship between the fraction of colloids retained along a fracture (Fr) and the parameters describing the aquifer’s physical and chemical properties; iii) developing an analytical model for the relationship between Fr and the coefficient describing irreversible colloid deposition in single fractures; and, iv) developing a numerical technique that can efficiently simulate colloid behavior in single fractures and fracture networks under different physical, chemical, and matrix conditions. The performance of the synchronization-based framework, mathematical and analytical models, and the numerical technique was assessed separately for different verification cases, and the corresponding efficacy was confirmed. Coupling the tools developed in the present study enables the reliable prediction of colloid behavior in response to changes in the groundwater-colloid-fracture system’s physical and chemical properties, which can aid in understanding how to manipulate the system’s properties for the effective design of groundwater quality management and remediation strategies. / Thesis / Doctor of Philosophy (PhD) / Microorganisms, microplastics, clay, and fine silt are classified as colloids within the spectrum of contaminants that might exist in groundwater. Although some colloids are benign (e.g., clay and fine silt), they can still affect the groundwater quality and aquifer porosity. Colloids can also enhance or inhibit the migration of other contaminants in groundwater because of their high adsorption capacity. Several remediation strategies are being envisioned to remove pathogenic colloids and eliminate other contaminants adsorbed onto benign colloids, where effective design of such strategies requires reliable models of colloid behavior. The present study aims at enhancing the reliability of simulating colloid behavior in fractured aquifers through: i) developing models that capture the effects of the aquifer’s physical and chemical properties on colloid behavior; and, ii) designing a framework that improves the reliability of aquifer conceptualization. Effective remediation strategies can then be designed for contaminated fractured aquifers based on the developed tools.
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/25057 |
| Date | January 2019 |
| Creators | Ahmed, Ahmed |
| Contributors | Dickson, Sarah, El-Dakhakhni, Wael, Civil Engineering |
| Source Sets | McMaster University |
| Language | English |
| Detected Language | English |
| Type | Thesis |
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