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Showing 1 to 19 of 19 for “"non-aqueous phase liquid"”.
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NAPL (Non Aqueous Phase Liquid) source characterization based on dissolved contaminant concentrations
… originates from spatially distributed sources of Non-Aqueous Phase Liquids (NAPLs). Such chemicals are typically persistent sources of groundwater contamination that are difficult to characterize. This work addresses the feasibility of using dissolved concentration measurements to estimate the …
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Investigation into dense non-aqueous phase liquid (DNAPL) transport and remediation in vertical fractures
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2000.
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Dynamics of residual non-aqueous phase liquids in porous media subject to freeze-thaw
… cycles on the pore-scale structure of nonaqueous phase liquid (NAPL) contaminants in water-saturated porous media. This problem is of critical importance to the entrapment of such contaminants in cold temperate, polar and high altitude regions, and has not been examined in the …
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Innovative Methods for Solving Multicomponent Biogeochemical Groundwater Transport on Supercomputers
… in situ bioremediation of subsurface NAPL (non-aqueous phase liquid) contamination on the ASCI Q supercomputer at Los Alamos National Laboratory, on which a study of parallel efficiency/scaling using up to 512 processors was conducted. Recently, researchers have been investigating …
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Effect of water table fluctuations on petroleum contamination distribution
… sand tank model. The experimental Light Non Aqueous Phase Liquid (LNAPL) was No. 2 Diesel fuel and the experimental media was sand (Sieve 20). A known quantity of fuel (5.65 Liters) was leaked into the tank at a leak rate of 0.75 L/hr. The water table level was raised at four different …
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Surfactant enhanced mobilisation of non-aqueous phase liquids
The remediation of non-aqueous phase liquid (NAPL) using conventional aquifer treatment technologies is limited by the low solubility of NAPLs. Surfactants can promote the enhanced removal of NAPL through mobilisation, a mechanism that relies on the reduction of interfacial tension (IFT) at the …
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Mass transfer from non-aqueous phase liquids to the aqueous phase in groundwater systems
… subsurface environment, a significant portion of non-aqueous phase liquids (NAPL's) is trapped by capillary forces and remains in the subsurface as immobile blobs or ganglia. Residual saturations of NAPL on the order of 5-30 percent have been observed in saturated subsurface systems. The NAPL can …
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Experimental analysis and modeling of transient dissolution of RDX through mass transfer processes
… with a least-squares method that approximated non-aqueous phase liquid (NAPL) dissolution [Miller et. al., 1990]. This study adjusted the constants developed with the obtained modified Sherwood number to model RDX. Modeling development used a modified Sherwood number in the form: ... The …
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Redutive Dehalogenation of Chlorinated Alkanes by Novel Bacteria at the PetroProcessor of Louisiana Inc. Superfund Site
… of dehalogenating bacteria within the dense non-aqueous phase liquid (DNAPL) source zone at the PPI site. Results revealed the presence of bacteria similar or identical to strains BL-DC-8 and BL-DC-9 as well as “Dehalococcoides” strains throughout the DNAPL source zone. 16S rRNA gene copy …
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Stability, transport and applications of polyaphrons in porous media
… light chemicals to lower the density of dense non-aqueous phase liquid (DNAPL) contaminants in situ. We first investigate how the stability of diluted polyaphrons is affected by the properties of the continuous phase. We find that polyaphrons can be destabilized by a low concentration of Al3+ …
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Characterization of Subsurface Heterogeneity Using Transient Hydraulic and Tracer Tomography
… to tracer tomography for characterizing NAPL (Non-aqueous phase liquid) source zones. Similar to a hydraulic tomographic survey, a tracer tomography survey sequentially injects tracers at a selected well and monitors tracer breakthroughs at other wells in a NAPL source zone to detect the …
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Vapor intrusion modeling : limitations, improvements, and value of information analyses
… or contaminant source concentrations, either in non-aqueous phase liquid (NAPL), groundwater, or soil. An analysis of two of the EPA-implemented J&E spreadsheet models, one that considers subsurface soil gas data and one that considers groundwater data, was conducted. The governing equations, …
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Quantification of Parameters in Models for Contaminant Dissolution and Desorption in Groundwater
… a simulated contaminant source zone and the aqueous phase. Where direct observation has fallen short, this study attempts to interpret field data using an inverse modeling technique for the purpose of constraining mass transfer processes which are poorly understood at the field scale. Inverse …
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Modeling of Foam Flow in Porous Media for Subsurface Environmental Remediation
… formations and shallow subsurface in-situ NAPL (non-aqueous phase liquid) environmental remediation in contaminated soils and aquifers. In those applications, foams are known to reduce the mobility of gas phase by increasing effective gas viscosity and improve sweep efficiency by mitigating …
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Effects of the Desorption and Dissolution of Polycyclic Aromatic Hydrocarbons on Phytoremediation at a Creosote-Contaminated Site
… concentration that readily desorbs to the aqueous phase for each PAH. Additionally, it was determined that the percent removal of sorbed PAH's decreases with increasing molecular weight. Desorption curves based on experimental data were found to exhibit linear behavior over large variations …
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Natural Attenuation Software (NAS): Assessing Remedial Strategies and Estimating Timeframes
… models include advection, dispersion, sorption, non-aqueous phase liquid (NAPL) dissolution, and biodegradation. NAS determines redox zonation, and estimates and applies varied biodegradation rates from one redox zone to the next. Recently, NAS was enhanced to include petroleum hydrocarbons, …
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Numerical Modeling of Steam Flushing for Removal of Dense Nonaqueous Phase Liquids
… of in situ thermal treatment technologies for non-aqueous phase liquid (NAPL) contaminants and a number of sophisticated numerical models have been developed for simulating thermal remediation. In the first part of this study the fundamental mechanisms associated with thermal remediation are …
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Computational Tools for Improved Analysis and Assessment of Groundwater Remediation Sites
Remediation of contaminated groundwater remains a high-priority national goal in the United States. Water is essential to life, and new sources of water are needed for an expanding population. Groundwater remediation remains a significant technical challenge despite decades of research into this …
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From Source to Surveillance: An Assessment of Liquid Elemental Mercury Mobilization in Soil, Downstream Reactivity, and Biomarkers of Exposure
… environment. One understudied form is that of liquid elemental mercury (Hg0L), a dense non-aqueous phase liquid which, upon release to the environment, can persist in soil for decades. Over time, this residual Hg0L is gradually released to groundwater and eventually surface water, serving as a …