In situ Air Sparging (IAS) and Soil Vapor Extraction (SVE) systems in the Subsurface Introduction Groundwater and soil contamination Non-Aqueous Phase Liquids (NAPLs) Heterogeneous porous media (subsurface system): Significant heterogeneities in terms of physicochemical and geological transport properties In situ Air Sparging (IAS) and Soil Vapor Extraction (SVE) Study objectives Three-dimensional models for groundwater flow and contaminant transport in subsurface system Optimization model for integrated IAS and SVE technology User-friendly window environment for input data generation Numerical simulation Finite Element Method (FEM) Monte Carlo Technique Optimization & Modified Genetic Algorithm High Performance Computing (HPC) system for computation-oriented procedure Program language : C/C++ & MS Visual C++ Application and Uses 3D numerical simulation in combined saturated and vadose zones Optimized remediation strategies for integrated IAS and SVE system Graphical environments for end users Practial remediation system setup and its application to contaminated sites
Read MoreConcentration Evolution of Gas Species within a Collapsing Bubble in a Liquid Medium Wonyong Jang and Mustafa M. Aral Multimedia Environmental Simulation Laboratory School of Civil and Environmental Engineering Georgia Institute of Technology, Atlanta, GA, USA Abstract: In this study numerical methods are used to investigate the relationship between chemical concentration of gas species within a cavitating bubble, equilibrium radius of the gas bubble and pressure variations in the ambient liquid. For this purpose, governing equations are developed to describe the dynamic equilibrium of a bubble in a flowing fluid and mass transfer between gas and liquid phases, where it was assumed that gases undergo isothermal compression, obey the ideal gas law, Henry law. It is further assumed that the concentration of each phase within the bubble is uniform. The resulting nonlinear equations are solved using implicit Trapezoidal method with Newton iteration. Four gas species are modeled under various initial
Read MoreOnce chlorinated volatile organic compounds (CVOCs) are released into the subsurface they are spread out through the porous soil matrix by complicated processes such as advection, dispersion, and sorption. CVOCs can be also biodegraded by indigenous microorganism via aerobic and anaerobic bioreactions, which generate distinct benign or harmful by-products. Heterogeneous subsurface characteristics and non-uniform distribution and consumption of oxygen in the subsurface may allow the dual bioreactions to coexist within a representative subsurface volume (RSV). The portion of each bioreaction within a RSV will depend on multiple factors such as oxygen, contaminant, and microorganism levels. Oxygen can be supplied into the contaminated zone through the dispersive and advective transport of oxygen in gas phase as well as the flow of the groundwater containing dissolved oxygen. As the dual bioreactions are coupled with multiple fluid flows (groundwater and gas) and multispecies transport, the analysis of the bioreactions is very complicated. However,
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