Modeling the Transport of Volatile Organic Chemicals in Variably Saturated Subsurface Regions

Modeling the Transport of Volatile Organic Chemicals in Variably Saturated Subsurface Regions PDF Author: Teresa Birnbaum Culver
Publisher:
ISBN:
Category : Groundwater
Languages : en
Pages : 310

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Modeling the Transport of Volatile Organic Chemicals in Variably Saturated Subsurface Regions

Modeling the Transport of Volatile Organic Chemicals in Variably Saturated Subsurface Regions PDF Author: Teresa Birnbaum Culver
Publisher:
ISBN:
Category : Groundwater
Languages : en
Pages : 310

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Mass Transport of Volatile Organic Compounds Between the Saturated and Vadose Zones

Mass Transport of Volatile Organic Compounds Between the Saturated and Vadose Zones PDF Author: Monte S. Harner
Publisher:
ISBN: 9781423573920
Category : Groundwater
Languages : en
Pages : 99

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Book Description
Volatile organic compounds (VOCs) dissolved in the saturated zone are transported into the vadose zone primarily by gaseous phase diffusion. If the saturated zone is remediated, VOCs present in the vadose zone may become a secondary source of contamination for the groundwater The amount of VOCs that remain in the vadose zone is dependent on site hydrology, soil properties, and the chemical properties of the contaminants. The purpose of this study was to determine what conditions caused VOC concentrations in the vadose zone to significantly recontaminate the saturated zone. A one-dimensional numerical model was developed to investigate the transport of a VOC, trichioroethylene, between the saturated and vadose zones under a variety of conditions. The model featured steady-state unsaturated water flow and transient contaminant transport Transport mechanisms included aqueous phase advection-dispersion and gaseous phase diffusion. Partitioning between the water, gas, and soil compartments were modeled as equilibrium processes. Sensitivity analyses were performed on several variables including soil type (homogeneous and heterogeneous profiles), water infiltration rate and vadose zone depth. Results indicated that recontamination was most significant rate, and vadose zone depth. Results indicated that recontamination was most significant in the presence of heterogeneous soils, low infiltration rates and deep vadose zones.

Masters Theses in the Pure and Applied Sciences

Masters Theses in the Pure and Applied Sciences PDF Author: Wade H. Shafer
Publisher: Springer Science & Business Media
ISBN: 1461534747
Category : Science
Languages : en
Pages : 421

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Book Description
Masters Theses in the Pure and Applied Sciences was first conceived, published, and disseminated by the Center for Information and Numerical Data Analysis and Synthesis (CINDAS) * at Purdue University in 1957, starting its coverage of theses with the academic year 1955. Beginning with Volume 13, the printing and dissemination phases of the activity were transferred to University Microfilms/Xerox of Ann Arbor, Michigan, with the thought that such an arrangement would be more beneficial to the academic and general scientific and technical community. After five years of this joint undertaking we had concluded that it was in the interest of all con cerned if the printing and distribution of the volumes were handled by an interna tional publishing house to assure improved service and broader dissemination. Hence, starting with Volume 18, Masters Theses in the Pure and Applied Sciences has been disseminated on a worldwide basis by Plenum Publishing Cor poration of New York, and in the same year the coverage was broadened to include Canadian universities. All back issues can also be ordered from Plenum. We have reported in Volume 34 (thesis year 1989) a total of 13,377 theses titles from 26 Canadian and 184 United States universities. We are sure that this broader base for these titles reported will greatly enhance the value of this important annual reference work. While Volume 34 reports theses submitted in 1989, on occasion, certain univer sities do report theses submitted in previous years but not reported at the time.

Modeling the Transport of Volatile Organic Chemicals in Unsaturated Media

Modeling the Transport of Volatile Organic Chemicals in Unsaturated Media PDF Author: Lawrence C. Krause
Publisher:
ISBN:
Category :
Languages : en
Pages : 158

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Unsteady Multiphase Flow Modeling of IN-SITU Air Sparging System in a Variable Saturated Subsurface Environment

Unsteady Multiphase Flow Modeling of IN-SITU Air Sparging System in a Variable Saturated Subsurface Environment PDF Author: Wonyong Jang
Publisher:
ISBN:
Category : Groundwater
Languages : en
Pages :

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Book Description
In order to preserve groundwater resources from contamination by volatile organic compounds and to clean up sites contaminated with the compounds, we should understand fate and transport of contaminants in the subsurface systems and physicochemical processes involving remediation technologies. To enhance our understanding, numerical studies were performed on the following topics: (i) multiphase flow and contaminant transport in subsurface environments; (ii) biological transformations of contaminants; (iii) in-situ air sparging (IAS); and, thermal-enhanced venting (TEV). Among VOCs, trichloroethylene (TCE) is one of the most-frequently-detected chemicals in the contaminated groundwater. TCE and its daughter products (cis-1,2-dichloroethylene (cDCE) and vinyl chloride (VC)) are chosen as target contaminants. Density-driven advection of gas phase is generated by the increase in gas density due to vaporization of high-molecular weight contaminants such as TCE in the unsaturated zone. The effect of the density-driven advection on fate and transport of TCE was investigated under several environmental conditions involving infiltration and permeability. Biological transformations of contaminants can generate byproducts, which may become new toxic contaminants in subsurface systems. Sequential biotransformations of TCE, cDCE, and VC are considered herein. Under different reaction rates for two bioreaction kinetics, temporal and spatial concentration profiles of the contaminants were examined to evaluate the effect of biotransformations on multispecies transport. IAS injects clean air into the subsurface below the groundwater table to remediate contaminated groundwater. The movement of gas and the groundwater as a multiphase flow in the saturated zone and the removal of TCE by IAS application were analyzed. Each fluid flow under IAS was examined in terms of saturation levels and fluid velocity profiles in a three-dimensional domain. Several scenarios for IAS systems were simulated to evaluate remedial performance of the systems. TEV was simulated to investigate its efficiency on the removal of a nonaqueous phase liquid in the unsaturated zone under different operational conditions. For numerical studies herein, the governing equations for multiphase flow, multispecies transport, and heat energy in porous media were developed and solved using Galerkin finite element method. A three-dimensional numerical model, called TechFlowMP model, has been developed.

Natural Attenuation Potential of Chlorinated Volatile Organic Compounds in Ground Water, TNX Flood Plain, Savannah River Site, South Carolina

Natural Attenuation Potential of Chlorinated Volatile Organic Compounds in Ground Water, TNX Flood Plain, Savannah River Site, South Carolina PDF Author:
Publisher:
ISBN:
Category : Floodplain management
Languages : en
Pages : 58

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Sorption of Volatile Organic Compounds and Their Mixtures on Synthetic and Natural Soils

Sorption of Volatile Organic Compounds and Their Mixtures on Synthetic and Natural Soils PDF Author: Sharon Ruth Lindner
Publisher:
ISBN:
Category :
Languages : en
Pages : 506

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Subsurface Flow and Transport of Organic Chemicals

Subsurface Flow and Transport of Organic Chemicals PDF Author: G. P. Streile
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Probabilistic Forecasting of Volatile Organic Compound Concentrations at the Soil Surface from Contaminated Groundwater

Probabilistic Forecasting of Volatile Organic Compound Concentrations at the Soil Surface from Contaminated Groundwater PDF Author: James Justin Joseph Clark
Publisher:
ISBN:
Category :
Languages : en
Pages : 432

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Subsurface Transport and Fate Processes

Subsurface Transport and Fate Processes PDF Author: Robert C. Knox
Publisher: CRC Press
ISBN:
Category : Business & Economics
Languages : en
Pages : 456

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Book Description
Background; Hydrodynamic processes; Abiotic processes; Biotic e processes; Physical models of contaminant transport; Empirical models and vulnerability mapping; Modelling subsurface transport and fate processes, Applicationds of transport and fate information.