Dissolution Of Nonaqueous Phase Liquid Pools In Saturated Porous Media

Volume 3: Engineering Modeling and Sustainability. This 3-volume reference presents the latest findings in impact assessment of recycled hazardous waste materials on surface and ground waters. Topics covered include chemodynamics, toxicology, modeling and information systems. The book serves as a practical guide for the monitoring, design, management, or conduct of environmental impact assessment. Each volume contains the table of contents of all volumes.

An evolving, living organic/inorganic covering, soil is in dynamic equilibrium with the atmosphere above, the biosphere within, and the geology below. It acts as an anchor for roots, a purveyor of water and nutrients, a residence for a vast community of microorganisms and animals, a sanitizer of the environment, and a source of raw materials for co

Diffusion in Natural Porous Media: Contaminant Transport, Sorption/Desorption and Dissolution Kinetics introduces the general principles of diffusion in the subsurface environment and discusses the implications for the fate and transport of contaminants in soils and groundwater. Emphasis is placed on sorption/desorption and the dissolution kinetics of organic contaminants, both of which are limited by the slow speed of molecular diffusion. Diffusion in Natural Porous Media: Contaminant Transport, Sorption/Desorption and Dissolution Kinetics compiles methods for calculating the diffusion coefficients of organic compounds (in aqueous solution or vapor phase) in natural porous media. The author uses analytical solutions of Fick's 2nd law and some simple numerical models to model diffusive transport under various initial and boundary conditions. A number of these models may be solved using spreadsheets. The book examines sorption/desorption rates of organic compounds in various soils and aquifer materials, and also examines the dissolution kinetics of nonaqueous phase liquids in aquifers, in both the trapped residual phase and in pools. Diffusion in Natural Porous Media: Contaminant Transport, Sorption/Desorption and Dissolution Kinetics concludes with a discussion of the impact of slow diffusion processes on soil and groundwater decontamination and the implications of these processes for groundwater risk assessment.

The transport and dissolution of residual non-aqueous phase liquids (NAPLS) trapped in water saturated porous media is a problem pertinent to both environmental and petrochemical industries. In this work we have quantitatively examined the complete dissolution of residual entrapped NAPL at the pore-scale in three dimensions using refractive index matching techniques along with planar laser induced fluorescence. The results yielded pore-scale information regarding ganglia volume, surface area, and position over time at various Capillary numbers. We found that with increasing Capillary numbers, the time for total dissolution decreased. In addition, it appears that large ganglia exhibit fractal area to volume scaling. We were also able to examine the distributions of the ganglia in the direction of flow over time. The use of low-frequency flow pulsations as a removal technique was also examined. A two dimensional micro model was used for these studies. We found that for this system, lower frequencies and higher amplitudes were more effective in NAPL removal due to breakup and mobilization. We also examined the effect of increasing amplitude and continuous versus pulsed stimulation. In addition, mass transport in the presence of a surfactant was also enhanced due to flow pulsation with lower frequencies and higher amplitudes again being most effective.