Download or read book Dissolution of Multicomponent Non aqueous Phase Liquids Sources written by and published by . This book was released on 2005 with total page 319 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Dissolution from Multicomponent Nonaqueous Phase Liquids NAPLs written by Priti P. Brahma and published by . This book was released on 2000 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Characterization Dissolution and Enhanced Solubilization of Multicomponent Nonaqueous Phase Liquid in Porous Media written by Kenneth Cooper Carroll and published by . This book was released on 2007 with total page 518 pages. Available in PDF, EPUB and Kindle. Book excerpt: Multicomponent nonaqueous phase liquids (NAPL) contaminating the subsurface can significantly inhibit remediation. One method of enhancing the rate of remediation of NAPL constituents, compared to pump-and-treat, involves source zone treatment with enhanced solubilization agents (ESAs) including cyclodextrins. Equilibrium cyclodextrin enhanced solubilization of simple 1, 2, and 3 component NAPL mixtures was examined to evaluate the applicability of Raoult's Law. The results suggest that Raoult's Law may be used to estimate equilibrium and early-time dynamic concentrations in contact with ideal NAPL mixtures, and Raoult's Law may be used to estimate cyclodextrin enhanced groundwater concentrations for ideal NAPL mixtures. Solubility enhancement of NAPL compounds was dependent on the cyclodextrin concentration and independent of NAPL composition. Column experiments and numerical modeling were used to evaluate the dissolution behavior of the NAPL mixtures in water and a cyclodextrin solution to estimate mass transfer rates. The aqueous multicomponent dissolution followed Raoult's Law, and the model-estimated lumped rate coefficients were independent of the NAPL composition. Addition of the cyclodextrin enhanced the dissolution and removal of compounds from residual NAPL due to an increase in the driving force (i.e. concentration gradient) and the mass transfer coefficient. The model results suggest that Raoult's Law is applicable for ideal NAPL mixture dissolution in water, but potential nonideality was observed and caused the model simulation to deviate from the dissolution behavior for NAPL mixture cyclodextrin experiments. The cyclodextrin dissolution experiments were less rate-limited than aqueous dissolution, and the mass transfer coefficients were quantified with the model. The results of the model suggest that NAPL mixture nonideality and intra-NAPL diffusion may also impact enhanced dissolution behavior. Additionally, the importance of NAPL mixture characterization was illustrated by evaluation of a mixture of PCE (tetrachloroethene) and diesel fuel collected from a site in Tucson, Arizona. A sample from the site was used to create mixtures with increasing PCE in the NAPL. Chemical evaluation of the complex NAPL was conducted, and physical property and phase partitioning testing was performed, which demonstrated the effect of NAPL composition on its distribution, interphase mass transfer, and potential mobilization.
Download or read book Dissolution and Mass Flux from Trichloroethene and Toluene Hexadecane Multicomponent Nonaqueous Phase Liquid NAPL Mixtures written by Mark Padgett and published by . This book was released on 2015 with total page 61 pages. Available in PDF, EPUB and Kindle. Book excerpt: Remediation efforts and contaminant transport predictions generally neglect the complicated dissolution and transport behavior associated with multi-component nonaqueous phase liquid (NAPL) sources. Therefore, it is important to understand the diffusion and dissolution processes occurring in these multicomponent systems as a function of mole fraction, molecular similarity/dissimilarity, and nonideal hydraulic factors. A series of laboratory scale NAPL-aqueous phase dissolution experiments were conducted to assess dissolution and intra- NAPL diffusion as a function of multicomponent NAPL composition (mole fraction) for both trichloroethene (TCE) and toluene (TOL). Predetermined volumes of target NAPL compounds were mixed with an insoluble n-hexadecane (HEX) NAPL to create mixtures that vary by NAPL composition. The ideality of resulting target compound dissolution was evaluated by quantifying NAPL-phase activity coefficient through Raoult's Law analysis. The results show that dissolution from the NAPL mixtures behave ideally for mole fractions above 0.2. As the target compound fraction of the NAPL mixture gets smaller, the dissolution behavior becomes increasingly nonideal (larger NAPL-phase activity coefficients). The TOL:HEX mole fraction mixtures show greater nonideality at equilibrium and initial elution concentrations for batch and column experiments when compared to TCE:HEX systems. Mass flux reduction analysis shows that the 0.5:0.5:, 0.2:0.8, and 0.1:0.9 mole fractions of both TCE and TOL behave similarly while the 0.05:0.95 mole fractions of TCE and TOL behave the most nonideally and exhibit mass flux reduction before any other mole fractions. Overall, the dissolution rates were constant and not controlled by NAPL composition-dependent factors. The results of this work may be used to improve transport predictions, remediation design, and risk assessments especially for sites contaminated by complex NAPL mixtures.
Download or read book Introduction to Environmental Forensics written by Brian L. Murphy and published by Academic Press. This book was released on 2014-07-30 with total page 747 pages. Available in PDF, EPUB and Kindle. Book excerpt: The third edition of Introduction to Environmental Forensics is a state-of-the-art reference for the practicing environmental forensics consultant, regulator, student, academic, and scientist, with topics including compound-specific isotope analysis (CSIA), advanced multivariate statistical techniques, surrogate approaches for contaminant source identification and age dating, dendroecology, hydrofracking, releases from underground storage tanks and piping, and contaminant-transport modeling for forensic applications. Recognized international forensic scientists were selected to author chapters in their specific areas of expertise and case studies are included to illustrate the application of these methods in actual environmental forensic investigations. This edition provides updates on advances in various techniques and introduces several new topics. Provides a comprehensive review of all aspects of environmental forensics Coverage ranges from emerging statistical methods to state-of-the-art analytical techniques, such as gas chromatography-combustion-isotope ratio mass spectrometry and polytopic vector analysis Numerous examples and case studies are provided to illustrate the application of these forensic techniques in environmental investigations
Download or read book Quantifying Mass Transfer Processes in Groundwater as a Function of Molecular Structure Variation for Multicomponent NAPL Sources written by Joe Boone Abbott and published by . This book was released on 2018 with total page 88 pages. Available in PDF, EPUB and Kindle. Book excerpt: The presence of nonaqueous phase liquids (NAPLs) in soil and groundwater is difficult and expensive to remediate. Complications exist for remediation of multicomponent NAPL sources due to differences in dissolution behavior at the molecular level. The dissolution behavior of two contaminants of concern (COC), trichloroethene (TCE) and toluene (TOL), was compared as binary mixtures within hexane, decane, and hexadecane. The relative ideality of mass transfer processes for TCE and TOL from the binary NAPL mixtures was evaluated by comparing aqueous-phase COC concentrations calculated using Raoult's Law to the observed equilibrium aqueous-phase COC concentrations for a series of batch dissolution experiments. As mole fraction ratios of the COCs (i.e., TCE and TOL) within the NAPL source decrease, dissolution nonideality generally increases for such multicomponent NAPL mixtures. A series of comprehensive equilibrium batch experiments was conducted to understand and quantify the systematic influence of bulk NAPL carbon-chain length on the dissolution behavior of TCE and TOL. The differences between the observed COC equilibrium and Raoult's Law-predicted concentrations are likely due to specific intra-NAPL component interactions that occur and thereby affect mass transfer dynamics from the multicomponent NAPL mixture. However, no particular correlation between the observed COC aqueous-phase equilibrium concentrations (via dissolution) and the COC-NAPL mixture's bulk NAPL carbon chain length was determined. A static equilibrium-solubility model was used to estimate activity coefficients for TCE and TOL within various carbon-length aliphatic bulk NAPL mixtures (i.e., hexane, decane, hexadecane). The xlUNIFAC Model was used to simulate the mixtures for comparison to the batch experimental systems, following the UNIFAC group contribution methods for estimating phase equilibrium. TOL (aromatic structure) showed greater nonideal dissolution behavior than TCE (aliphatic structure) in the presence of the different bulk-NAPL components used for this study. The results of this work suggest that the prediction of aqueous phase concentrations in groundwater of COCs from complex multicomponent NAPL sources is highly dependent upon both compositional and molecular structural variations. Such impacts should be taken into account when designing and evaluating a particular remediation strategy and/or predicting COC concentrations from a NAPL source zone region.
Download or read book Chlorinated Solvent Source Zone Remediation written by Bernard H. Kueper and published by Springer Science & Business. This book was released on 2014-04-22 with total page 759 pages. Available in PDF, EPUB and Kindle. Book excerpt: The purpose of this book is to help engineers and scientists better understand dense nonaqueous phase liquid (DNAPL) contamination of groundwater and the methods and technology used for characterization and remediation. Remediation of DNAPL source zones is very difficult and controversial and must be based on state-of-the-art knowledge of the behavior (transport and fate) of nonaqueous phase liquids in the subsurface and site specific geology, chemistry and hydrology. This volume is focused on the characterization and remediation of nonaqueous phase chlorinated solvents and it is hoped that mid-level engineers and scientists will find this book helpful in understanding the current state-of-practice of DNAPL source zone management and remediation.
Download or read book Dissolution and Desorption Characteristics of Aromatic Compounds from Media Contaminated with Multicomponent Petroleum Hydrocarbons written by Sanjay Garg and published by . This book was released on 1998 with total page 340 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Contaminants in the Subsurface written by National Research Council and published by National Academies Press. This book was released on 2005-04-23 with total page 371 pages. Available in PDF, EPUB and Kindle. Book excerpt: At hundreds of thousands of commercial, industrial, and military sites across the country, subsurface materials including groundwater are contaminated with chemical waste. The last decade has seen growing interest in using aggressive source remediation technologies to remove contaminants from the subsurface, but there is limited understanding of (1) the effectiveness of these technologies and (2) the overall effect of mass removal on groundwater quality. This report reviews the suite of technologies available for source remediation and their ability to reach a variety of cleanup goals, from meeting regulatory standards for groundwater to reducing costs. The report proposes elements of a protocol for accomplishing source remediation that should enable project managers to decide whether and how to pursue source remediation at their sites.
Download or read book Dense Nonaqueous Phase Liquids written by and published by . This book was released on 1992 with total page 92 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Groundwater and Soil Cleanup written by National Research Council and published by National Academies Press. This book was released on 1999-11-21 with total page 301 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents a comprehensive, up-to-date review of technologies for cleaning up contaminants in groundwater and soil. It provides a special focus on three classes of contaminants that have proven very difficult to treat once released to the subsurface: metals, radionuclides, and dense nonaqueous-phase liquids such as chlorinated solvents. Groundwater and Soil Cleanup was commissioned by the Department of Energy (DOE) as part of its program to clean up contamination in the nuclear weapons production complex. In addition to a review of remediation technologies, the book describes new trends in regulation of contaminated sites and assesses DOE's program for developing new subsurface cleanup technologies.
Download or read book Proceedings of the 51st Purdue Industrial Waste Conference1996 Conference written by Purdue Research Foun and published by CRC Press. This book was released on 1997-05-01 with total page 792 pages. Available in PDF, EPUB and Kindle. Book excerpt: The papers presented at the 51st Purdue Industrial Waste Conference have been divided into the following sections: pollution prevention site remediation physical and chemical processes odor and VOC control solidification, foundry, and combustion residues biological processes respirometry and effluent toxicity industrial waste case histories Each chapter contains a multitude of figures and tables illustrating the concepts discussed as well as extensive references for further study.
Download or read book Dissolution of Nonaqueous Phase Liquids in Saturated Subsurface Systems written by Susan E. Powers and published by . This book was released on 1992 with total page 406 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Dense Nonaqueous Phase Liquids written by Scott G. Huling and published by . This book was released on 1991 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Enhanced solubilization of Multicomponent Dense Immiscible Liquid in Homogeneous Porous Media written by David Slavic and published by . This book was released on 2014 with total page 95 pages. Available in PDF, EPUB and Kindle. Book excerpt: Complex multi-component nonaqueous phase liquid (NAPL) mixtures can significantly limit the effectiveness of groundwater remediation. The use of enhanced-flushing technologies has emerged as a promising technique for the remediation of sites contaminated with NAPL. A series of one-dimensional column experiments was conducted to quantify the effectiveness of four flushing agents (also called "solubilizing agents"; the terms are synonymous in this study) for the removal of a uniformly distributed multi-component NAPL source within a homogeneous porous medium. The columns were established with NAPL saturations (Sn) targeted between 10- 20%, consisting of an equal 1:1:1 mole mixture of tetrachloroethene (PCE), trichloroethene (TCE), and cis-1,2-dichloroethene (DCE). The solubilization agents investigated included 5 wt.% solutions of two complexing sugars: hydroxypropyl-beta-cyclodextrin (HPCD) and methyl-beta-cyclodextrin (MCD), a 5 wt.% solution of a surfactant: sodium dodecyl sulfate (SDS), and a 50 wt.% solution of ethanol (EtOH). For comparison purposes, a water flush (pump-and-treat) experiment was also conducted as a control, representing the system by which no enhanced- solubilization occurred. In general, initial effluent NAPL concentrations were successfully predicted using Raoult's Law, with minimal deviation (error) between the observed and predicted concentrations. The experimental data were used to test the efficiency of each flushing agent by analyzing the normalized contaminant mass recovery, the mass ratio of contaminant removed to reagent used, and the mole ratio of contaminant removed to reagent used. Mass flux reduction analysis was also used to test the efficiency of the various flushing agents. The results of the analyses showed that EtOH was the most efficient flushing agent when analyzed based on a normalized mass recovery basis. SDS exhibited the most efficient removal when the experiments were analyzed by mass-contaminant removed to mass reagent used. Based on the moles-contaminant removed to moles reagent used ratio efficiency evaluation, MCD was the most effective flushing agent. The results of these experiments indicate that the addition of a chemical flushing agent greatly reduces the time needed to remove each NAPL component, compared to flushing with water alone (i.e., pump and treat). PCE showed the greatest relative solubility enhancement for all enhanced flushing agents tested. MCD and SDS were most effective flushing agents for the three-component NAPL system, removing all three components (DCE/TCE/PCE) with the least number of pore volumes. The HPCD flush showed no appreciable solubility enhancement for DCE and TCE; however, PCE did show a 10-fold enhancement in solubility for this experiment. In terms of mass flux reduction/mass removal (MFR/MR) evaluation, DCE (the highest solubility NAPL component) exhibited the greatest nonideal (inefficient) response during both the water and HPCD flushing experiments. Mass flux reduction behavior was less ideal for the MCD flush compared to the other enhanced-flushing agents. EtOH showed superior performance when evaluated based on a normalized contaminant mass recovery basis, but showed relatively poor performance based on a mass ratio or mole ratio removal evaluation. SDS surpassed all other flushing agents based on a contaminant mass- recovery to reagent used basis, whereas MCD exceeded the removal efficiencies of the other enhanced flushing agents. In general, technical grade HPCD and MCD are more expensive than SDS and EtOH, and therefore may be less desirable choices for use at greater scales; however, their toxicities to microbial communities in the subsurface and potential concerns to human health and the environment are negligible compared to SDS and EtOH. Results from this study indicate that several criteria should be used to evaluate the removal effectiveness of flushing agents for multi-component NAPL systems. Due to the variety of remediation scenarios that could be encountered in the field, these findings will be helpful in developing more efficient and effective remediation strategies and for enabling more accurate prediction of resulting NAPL concentrations to meet the needs of various contaminated sites impacted by chlorinated compounds such as PCE, TCE, and DCE.
Download or read book Handbook of Soil Sciences Two Volume Set written by Pan Ming Huang and published by CRC Press. This book was released on 2018-10-03 with total page 2249 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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
Download or read book Dissolution of Nonaqueous Phase Liquids in Saturated Subsurface Systems written by Susan E. Powers and published by . This book was released on 1992 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt:
