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.

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.

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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Book Description


Volatile Organic Compounds in the Environment

Volatile Organic Compounds in the Environment PDF Author: Wun-cheng Wang
Publisher: ASTM International
ISBN: 0803120486
Category : Biodegradation
Languages : en
Pages : 289

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Book Description
Papers delivered at the symposium of the same name, April 1994, by speakers from seven nations. Twenty presentations are arranged under six topics: regulation and assessment, air quality, environmental fate, environmental measurement, environmental monitoring, and control and remediation. A sampling

Coupled Processes: Diffusive Transport and Biodegradation of Volatile Organic Compounds in Unsaturated Porous Media

Coupled Processes: Diffusive Transport and Biodegradation of Volatile Organic Compounds in Unsaturated Porous Media PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 26

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Book Description
Diffusive transport of volatile organic compounds (VOCs) and their degradation by bacteria in unsaturated soils are coupled by poorly understood mass transfer kinetics at the gas/water interface. The capability to predict the fate of VOCs in m saturated soil is necessary to evaluate the feasibility of natural attenuation as a VOC remediation strategy. The objective of this study was to develop a mechanistically based mathematical model that considered the interdependence of VOC diffusive transport, mass transfer at the gas/water interface, microbial activity, and sorptive interactions in a moist, unsaturated soil. Because the focus of the model was on description of natural attenuation, the advective VOC transport that is induced in engineered remediation processes such as vapor extraction was not considered. The utility of the model was assessed through its ability to describe experimental observations from well-defined experiments in which toluene was used as a representative VOC and diffused through soil columns that contained a toluene degrading bacterium, Pseudomonasputida. The coefficient for gas-liquid mass-transfer, KLa, was found to be a key parameter controlling the ability of bacteria to degrade VOCs. This finding indicates that soil size and geometry are likely to be dominant parameters in assessing the possible success of natural attenuation of VOCs in contaminated unsaturated soils.

Laboratory Study of Volatile Organic Compound Partitioning Vapor/aqueous/soil

Laboratory Study of Volatile Organic Compound Partitioning Vapor/aqueous/soil PDF Author: Alan Dole Hewitt
Publisher:
ISBN:
Category : Organic compounds
Languages : en
Pages : 28

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Book Description


Assessing the Mobility of Chemicals in the Vadose Zone

Assessing the Mobility of Chemicals in the Vadose Zone PDF Author: Donn Louis Marrin
Publisher:
ISBN:
Category : Chemical reactions
Languages : en
Pages : 78

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Book Description


Vadose Zone Hydrology

Vadose Zone Hydrology PDF Author: Marc B. Parlange
Publisher: Oxford University Press, USA
ISBN: 0195109902
Category : Electronic books
Languages : en
Pages : 473

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Book Description
The vadose zone is the region between ground level and the upper limits of soil fully saturated with water. Hydrology in the zone is complex: nonlinear physical, chemical, and biological interactions all affect the transfer of heat, mass, and momentum between the atmosphere and the water table. This book takes an interdisciplinary approach to vadose zone hydrology, bringing together insights from soil science, hydrology, biology, chemistry, physics, and instrumentation design. The chapters present state-of-the-art research, focusing on new frontiers in theory, experiment, and management of soils. The collection addresses the full range of processes, from the pore-scale to field and landscape scales.

Transport and Transformations of Volatile Organic Chemicals in Unsaturated Soils

Transport and Transformations of Volatile Organic Chemicals in Unsaturated Soils PDF Author: Yan Jin
Publisher:
ISBN:
Category : Biodegradation
Languages : en
Pages : 326

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Book Description


Selected Water Resources Abstracts

Selected Water Resources Abstracts PDF Author:
Publisher:
ISBN:
Category : Water
Languages : en
Pages : 962

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Book Description


Contaminant Hydrogeology

Contaminant Hydrogeology PDF Author: C. W. Fetter
Publisher: Waveland Press
ISBN: 1478636505
Category : Science
Languages : en
Pages : 663

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Book Description
Tremendous progress has been made in the field of remediation technologies since the second edition of Contaminant Hydrogeology was published two decades ago, and its content is more important than ever. Recognizing the extensive advancement and research taking place around the world, the authors have embraced and worked from a larger global perspective. Boving and Kreamer incorporate environmental innovation in studying and treating groundwater/soil contamination and the transport of those contaminants while building on Fetter’s original foundational work. Thoroughly updated, expanded, and reorganized, the new edition presents a wealth of new material, including new discussions of emerging and potential contaminant sources and their characteristics like deep well injection, fracking fluids, and in situ leach mining. New sections cover BET and Polanyi adsorption potential theory, vapor transport theory, the introduction of the Capillary and Bond Numbers, the partitioning interwell tracer testing technique for investigating NAPL sites, aerial photographic interpretation, geophysics, immunological surveys, high resolution vertical sampling, flexible liner systems, groundwater tracers, and much more. Contaminant Hydrogeology is intended as a textbook in upper level courses in mass transport and contaminant hydrogeology, and remains a valuable resource for professionals in both the public and private sectors.