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 Rate Limited Diffusion and Dissolution of Multi component Non aqueous Phase Liquids NAPLs in Groundwater written by William Randolph Burke and published by . This book was released on 2011 with total page 108 pages. Available in PDF, EPUB and Kindle. Book excerpt: Contamination of soil and groundwater by nonaqueous phase liquids (NAPLs) poses serious risks to human health and the environment and presents major challenges for cleanup. The presence of complex NAPL mixtures in the subsurface further complicates remediation efforts, transport predictions, and the development of accurate risk assessments. A comprehensive laboratory-scale study was conducted to elucidate the factors affecting dissolution and removal of NAPL including 1) the distribution of NAPL (uniform vs. non-uniform), 2) NAPL-water interfacial area (constant vs. changing), 3) multi-component NAPL systems (composition dependence), and 4) intra-NAPL diffusion. A series of column and time sequential batch experiments were conducted to assess the factors controlling dissolution processes under dynamic flow and equilibrium conditions. For comparison purposes, two independent NAPL systems were established for the series of experiments including single-component trichloroethene (TCE) whereby the NAPL interfacial area decreases as dissolution proceeds, and two-component TCE-hexadecane (HEX) in which the bulk NAPL (comprised primarily of insoluble HEX) interfacial remains constant. The results of this study show that significant dissolution rate and removal limitations during water-flushing exist for systems containing non-uniform NAPL (TCE) distributions, due to less available NAPL-water interfacial area. Effective TCE removal was 2 times longer for the non-uniform NAPL distribution experiment. TCE dissolution in the two-component NAPL systems (TCE and HEX) experienced significantly less rate limitation (absence of concentration tailing) than the single-component TCE systems due to the presence of a constant interfacial area for mass-transfer to occur during flushing. Each column experiment resulted in differing effectiveness with respect to mass removal. The multi-component TCE:HEX system experienced the fastest mass removal time, but was not considered the most efficient. The batch experiments demonstrated that as mole fraction of a particular component of a NAPL (TCE) mixture decreases, greater dissolution nonideality occurs, resulting in greater observed concentrations than those predicted by equilibrium dissolution (i.e. Raoult's Law). Dissolution nonideality, quantified by the NAPL-activity coefficient, increased for the lower TCE mole fraction systems from 1.7 to 6.1 for TCE:HEX mole fractions of 0.2:0.8 to 0.003:0.997, respectively. The results of the batch experiments also indicate that dissolution mass-transfer rates were nearly identical for both the single-component TCE systems and the TCE:HEX systems. This suggests that intra-NAPL diffusion is not a rate-limited process under the conditions of these experiments. Mass flux reduction analyses showed that the two-component (TCE:HEX) NAPL experiment resulted in less efficient removal behavior than the single-component TCE flushing experiments, likely due to the significantly lower TCE mass within the mixed NAPL system. The results from this study improved the understanding of NAPL dissolution and removal processes; most notably for NAPL mixture systems where NAPL-water interfacial area may be maintained during flushing and where significant dissolution nonideality may result from decreasing mole fractions of target contaminants in NAPL.

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 Light Nonaqueous Phase Liquids written by and published by . This book was released on 1995 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 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 Surfactants and Cosolvents for NAPL Remediation A Technology Practices Manual written by Donald F. Lowe and published by CRC Press. This book was released on 1999-03-26 with total page 444 pages. Available in PDF, EPUB and Kindle. Book excerpt: A $19.3 million Department of Defense grant to Rice University funds the Advanced Applied Technology Demonstration Facility (AATDF). One of the project goals is the development of reduction strategies for nonaqueous phase liquids (NAPLs) in the subsurface. Surfactants and Cosolvents for NAPL Remediation records the results of AATDF research. The manual is a guide to the practical application of surfactants/cosolvent for in situ remediation. It is targeted to decision makers and anyone concerned with the design or implementation of these technologies. The book discusses the situational viability of surfactants/cosolvents , the possible results, design, and operation. It includes case studies, step-by-step guidance, and project cost work sheets. The successful results of the AATDF research, as documented Surfactants and Cosolvents for NAPL Remediation, are an invaluable contribution to the future of subsurface remediation. Without source NAPL reduction, the alternative is decades of plume management through pump-and-treat.

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 Geoenvironmental Engineering written by Raymond Nen Yong and published by Thomas Telford. This book was released on 2004-06-30 with total page 618 pages. Available in PDF, EPUB and Kindle. Book excerpt: This new book contains the proceedings of the 4th Geoenvironmental Engineering Conference, organised by the British Geotechnical Association and Cardiff University’s School of Engineering, held in Stratford-Upon-Avon in June 2004. The theme of the conference was Integrated Management of Groundwater and Contaminated Land. This book is a compilation of peer-reviewed papers; grouped according to the sessions under which they were presented at the conference. Issues associated with Geoenvironmental Engineering continue to be a major preoccupation for Governments, public and private organisations and the general community around the world. The conference brought together people working in industry, academia and the public sector to discuss the latest ideas and developments in Geoenvironmental Engineering and related fields. The papers in these proceedings reflect the work being undertaken across the discipline. This volume is an indispensable source of information on current research and practice in the field of integrated management of groundwater and contaminated land.

Download or read book Dissolution of Non aqueous Phase Organic Liquids in Porous Media written by Jil Talkovsky Geller and published by . This book was released on 1990 with total page 412 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 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 Water Quality Management written by Vijay P Singh and published by Springer. This book was released on 2018-01-12 with total page 489 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book comprises two parts. The first part deals with some aspects of wastewater treatment, encompassing various types of technologies for treating wastewater and evaluation. The technologies, biochemical as well as chemical, including evaluation of technologies are also discussed. Part 2 is on solid waste management. It includes both municipal and industrial waste management. The book is of interest to researchers and practitioners in the field of water resources, hydrology, environmental resources, agricultural engineering, watershed management, earth sciences, as well as those engaged in natural resources planning and management. Graduate students and those wishing to conduct further research in water and environment and their development and management find the book to be of value.

Download or read book Innovative Approaches to the On Site Assessment and Remediation of Contaminated Sites written by Danny Reible and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 300 pages. Available in PDF, EPUB and Kindle. Book excerpt: 2 DANNY D. REIBLEI AND KATERINA DEMNEROVA 1 Hazardous Substance Research Center/South and Southwest, Louisiana State University, Baton Rouge, LA 70803 2 Department of Biochemistry and Microbiology, Institute of Chemical Technology, Prague, Czech Republic On May 24, 2001, a total of 102 students and lecturers participated in an Advanced Study Institute (ASI) sponsored by the North Atlantic Treaty Organization (NATO) under our direction. The Institute was focused on in situ and onsite management of contaminated sites. The objective of the Institute was to balance state of the art science with techniques for field application of a variety of technologies for in situ assessment and remediation of contaminated sites. Many of the lecturers were drawn from the ranks of the Hazardous Substance Research Centers, multi-university consortia that have been funded by the US Environmental Protection Agency to conduct research and technology transfer designed to promote risk-based management and control of hazardous substances for the nation. The Centers have made special contributions to the areas of in situ and onsite assessment and remediation of contaminated sites. Such approaches have the potential for being significantly less expensive than other assessment and remediation approaches while maintaining accuracy and effectiveness. Cost-effective remedial and management approaches that are also effective in minimizing exposure and risk to human health and the environment are a critical need throughout the world but particularly in Eastern Europe and the former Soviet Union where resources that can be devoted to environmental cleanup are especially limited.

Download or read book Development of a data evaluation decision support system for remediation of subsurface contamination written by and published by DIANE Publishing. This book was released on with total page 67 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Soil and Aquifer Pollution written by Hillel Rubin and published by Springer Science & Business Media. This book was released on 2013-03-09 with total page 428 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Water Research Institute at the Technion (Israel Institute of Technology) is proud to have initiated and sponsored the International Workshop "Soil and Aquifer Pollution: Non-Aqueous Phase Liquids - Contamination and Recla- tion", held May 13th-15th, 1996, on the Technion campus in Haifa. Groundwater contamination is one of the pressing issues facing Israel and other countries which depend on groundwater for water supply. In Israel, 60% of the water supply comes from groundwater, most of it from two large aquifers. The Coastal Aquifer underlies the area where the largest concentration of human activity already takes place, and where much of future development is expected to occur. It is a phreatic sandstone aquifer, vulnerable to pollution from activities at the surface. The Mountain Aquifer is recharged in the higher terrain to the east, and flows, first in a phreatic zone, then confined, westward and underneath the Coastal Aquifer. This limestone aquifer has higher permeabilities and flow velo- ties, so pollution can reach the groundwater quite readily. Smaller local aquifers are also important components in the national water system. While measures are taken to protect these aquifers from pollution, there are locations where contamination has already occurred. Furthermore, accidental pollution may not be totally avoided in the future. Therefore, understanding the processes of groundwater contamination, recommending the proper measures for preventing it, and determining the best means for reclamation once pollution has occurred, are of great practical importance. Non-aqueous phase liquids (NAPLs) are among the most significant contaminants.

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