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Showing 1 to 17 of 17 for “"reactive transport model"”.
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Investigating uranium mobility using groundwater 238U/235U data and a reactive transport model
… chemical reactions affecting the subsurface transport of the widespread contaminant uranium (U), we present a numerical reactive transport model which explicitly incorporates variations in the 238U/235U isotope ratio. Bioremediation, the microbial reductive immobilization of aqueous U(VI) to …
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Formation of mineralogical zonations in ophiolites through reactive porous flow : a modeling study
… rocks has been interpreted to be the result of reactive porous flow. From trace element data, the mafic melt has been interpreted to flow both into and out of the dunite dikes. Whether the melt emanates from the dunite bodies or is collected by them has implications for the mechanisms of melt …
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Silicate weathering in the Himalayas: Constraints from the Li isotopic composition of river systems
… weathering. The Li isotopic composition is modelled using a one-dimensional reactive transport model. The model incorporates the continuous input of Li from rock dissolution, removal due to secondary mineral formation, and hydrology along subsurface flow paths. Modelling shows that the Li …
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Numerical modeling of agricultural tile drainage water quality with health considerations
… was simulated using numerical methods and the reactive transport model TOUGHREACT to analyze these processes and thus better predict areas or scenarios of potential concern. Modeling results were calibrated and verified with 4 production agricultural field sites to better quantify and qualify …
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Linkages between fluid flow paths, reactive gases, and chemical weathering across a shale bedrock hillslope
… in combination with laboratory experiments and reactive transport modeling. The VMS allows for the direct observation of chemical and gas signatures in the vadose zone for the comparison of chemical evolution of fluids in lab experimental setting. We sampled water and gases across 18 meters of …
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Permanence and Life Cycle Performance of Biocementation Soil Improvement
… were then used to calibrate and validate a reactive transport model capable of forward predicting calcium carbonate dissolution spatially and temporally for a variety of different geochemical conditions. Next, direct simple shear tests were employed to examine the consequences of chemical …
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Modeling effective isotopic fractionation in groundwater aquifers with heterogeneous reaction rates
… aquifers. The goal of this study is to develop a reactive-transport model that may be used to determine the magnitude of isotopic shifts when reduction is unevenly distributed in aquifers (e.g., restricted to organic-rich lenses). This model incorporates heterogeneity and determines effective …
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Linking soil respiration to hydrologic conditions and climate change
… of such mechanisms into high-performance reactive transport frameworks is sparse and incomplete, and thus currently limits cross-field interpolations. To fill in these gaps, I have established a novel process-based reactive transport framework incorporating the transition between active …
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Biogeochemical controls on arsenic cycling in a hydrocarbon plume
… a threat to groundwater. In the third project, a reactive transport model simulates As cycling for 400 years. Results show that sorption of As to ferrihydrite limits As transport within 300 m of the hydrocarbon source. Modeling predicts that over the plume's lifespan, more groundwater will be …
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Forecasting groundwater contaminant plume development using statistical and machine learning methods
A persistent challenge in predicting the fate and transport of groundwater contaminants is the inherent geologic heterogeneity of the subsurface. Contaminant movement has been primarily modeled by simplifying the geology and accepting assumptions to solve the advection- dispersion-reaction …
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Methane cold seeps: Paleo proxies, modern measurements, and instrument development
… my proxy measurements. Using an isotope-enabled reactive-transport model, I show that the clumped isotopic composition of MDACs (the frequency of 13C–18O bonding within the carbonate lattice) quantitatively records AOM rates (Chapter 2) and derived global estimates of AOM rates at both modern …
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Geochemical records in travertine veins at the Green River CO2 seeps (Utah)
… and subsequently purified, compressed and transported. Some CO2 can be used for other processes, but excess CO2 can be injected into geological formations where it can be securely stored as either a gas, supercritical fluid or dissolved in formation fluids. Understanding the interactions of …
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A modeling framework for characterizing root exudation-driven geochemical dynamics in the Critical Zone
… practices have induced significant shifts in the transport and transformation of water, carbon, and nutrients across landscapes. The long-term implications of such changes on soil health and water chemistry remain an open challenge, and the mechanisms that drive changes in solute chemistry and …
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Interaction of aqueous U(VI) with goethite, montmorillonite, and UO2(s)
… of great concern throughout the world. Fate and transport of uranium in the subsurface can be controlled by U(VI) adsorption and reduction onto common iron (oxy)hydroxides and clay minerals. Aqueous U(VI) can also exchange uranium atoms with solids comprised of uranium which can potentially lead …
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Modeling nonpoint-source uranium pollution in an irrigated stream-aquifer system: calibration and simulation
… research is to develop a comprehensive numerical model for assessing U pollution in a stream-aquifer system within a large irrigated area. To achieve this, a computational model is built and tested that can predict with reasonable accuracy how U, along with Se and NO3, are mobilized and move …
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COMBINING GEOCHEMICAL AND NUMERICAL MODELING FOR CHLORINATED SOLVENTS GROUNDWATER CONTAMINATION
… if and how bioremediation is carried out. Reactive transport models (RTMs) are suitable tools to assist decision makers when designing and monitoring bioremediation efficiency. To date, no applications to SBSs have been reported, possibly owing to the relative novelty of SBS and to the …