BARRIER SYSTEMS for ENVIRONMENTAL CONTAMINANT CONTAINMENT and TREATMENT © 2006 by Taylor & Francis Group, LLC BARRIER SYSTEMS for ENVIRONMENTAL CONTAMINANT CONTAINMENT and TREATMENT Edited by Calvin C Chien • Hilary I Inyang Lorne G Everett Boca Raton London New York A CRC title, part of the Taylor & Francis imprint, a member of the Taylor & Francis Group, the academic division of T&F Informa plc © 2006 by Taylor & Francis Group, LLC 4040_Discl.fm Page Monday, September 26, 2005 11:08 AM Published in 2006 by CRC Press Taylor & Francis Group 6000 Broken Sound Parkway NW, Suite 300 Boca Raton, FL 33487-2742 © 2006 by Taylor & Francis Group, LLC CRC Press is an imprint of Taylor & Francis Group No claim to original U.S Government works Printed in the United States of America on acid-free paper 10 International Standard Book Number-10: 0-8493-4040-3 (Hardcover) International Standard Book Number-13: 978-0-8493-4040-6 (Hardcover) Library of Congress Card Number 2005047215 This book contains information obtained from authentic and highly regarded sources Reprinted material is quoted with permission, and sources are indicated A wide variety of references are listed Reasonable efforts have been made to publish reliable data and information, but the author and the publisher cannot assume responsibility for the validity of all materials or for the consequences of their use No part of this book may be reprinted, reproduced, transmitted, or utilized in any form by any electronic, mechanical, or other means, now known or hereafter invented, including photocopying, microfilming, and recording, or in any information storage or retrieval system, without written permission from the publishers For permission to photocopy or use material electronically from this work, please access www.copyright.com (http://www.copyright.com/) or contact the Copyright Clearance Center, Inc (CCC) 222 Rosewood Drive, Danvers, MA 01923, 978-750-8400 CCC is a not-for-profit organization that provides licenses and registration for a variety of users For organizations that have been granted a photocopy license by the CCC, a separate system of payment has been arranged Trademark Notice: Product or corporate names may be trademarks or registered trademarks, and are used only for identification and explanation without intent to infringe Library of Congress Cataloging-in-Publication Data Barrier systems for environmental contaminant containment and treatment / contributing editors, Calvin C Chien, Hilary I Inyang, Lorne G Everett ; prepared under the auspices of U.S Department of Energy, U.S Environmental Protection Agency, DuPont p cm Includes bibliographical references and index ISBN 0-8493-4040-3 (alk paper) In situ remediation Sealing (Technology) I Chien, Calvin C II Inyang, Hilary I III Everett, Lorne G IV United States Dept of Energy V United States Environmental Protection Agency VI E.I du Pont de Nemours & Company TD192.8.B375 2005 628.5 dc22 2005047215 Visit the Taylor & Francis Web site at http://www.taylorandfrancis.com Taylor & Francis Group is the Academic Division of Informa plc © 2006 by Taylor & Francis Group, LLC and the CRC Press Web site at http://www.crcpress.com 4040_C000.fm Page v Wednesday, September 21, 2005 4:38 PM Contributing Editors Calvin C Chien, Ph.D., P.E DuPont Fellow DuPont Wilmington, Delaware Hilary I Inyang, Ph.D Duke Energy Distinguished Professor and Director, Global Institute for Energy and Environmental Systems University of North Carolina, Charlotte, North Carolina Lorne G Everett, Ph.D., D.Sc President L Everett and Associates, LLC Santa Barbara, California Prepared under the auspices of U.S Department of Energy U.S Environmental Protection Agency DuPont With contributions by renowned experts on waste containment and waste treatment science and technology 2005 © 2006 by Taylor & Francis Group, LLC 4040_C000.fm Page vii Wednesday, September 21, 2005 4:38 PM Technical Review Board David E Daniel, Ph.D., Overall Book Reviewer University of Illinois Urbana-Champaign, Illinois Skip Chamberlain U.S Department of Energy Washington, DC Calvin C Chien, Ph.D., P.E DuPont Wilmington, Delaware Lorne G Everett, Ph.D., D.Sc L Everett and Associates, LLC Santa Barbara, California Brent E Sleep, Ph.D University of Toronto Toronto, Ontario, Canada Craig H Benson, Ph.D., P.E University of Wisconsin Madison, Wisconsin Annette M Gatchett U.S Environmental Protection Agency Washington, DC Ernest L Majer, Ph.D Lawrence Berkeley Laboratory Berkeley, California Hilary I Inyang, Ph.D University of North Carolina Charlotte, North Carolina David J Borns, Ph.D Sandia National Laboratories Albuquerque, New Mexico © 2006 by Taylor & Francis Group, LLC 4040_C000.fm Page ix Wednesday, September 21, 2005 4:38 PM Special Contributors Jada M Kanak, Special Technical Assistant DuPont Wilmington, Delaware Kathy O Adams, Contract Technical Writer DuPont Wilmington, Delaware © 2006 by Taylor & Francis Group, LLC 4040_C000.fm Page xi Wednesday, September 21, 2005 4:38 PM Introduction Significant advances in subsurface containment technology occurred in the 1990s, both with the improvement of the technology and the broader acceptance and applications as a measure for environmental remediation Since 1995, the U.S Department of Energy (USDOE), U.S Environmental Protection Agency (USEPA), and DuPont have collaborated on a series of organized efforts to advance this technology In that year, these collaborators sponsored an international expert workshop that led to the publication of the first major book on containment technology Two international conferences were held by the same three partners in 1997 and 2001, with individuals from all over the world attending Although subsurface containment technologies are becoming increasingly acceptable and popular in the environmental remediation field, questions remained on the prediction and verification of long-term barrier performance and this subject began to gain interest from the public, government agencies, and the U.S Congress With funding provided by USDOE, an executive committee, consisting of Skip Chamberlain (Chairperson, USDOE), Calvin C Chien (DuPont), and Annette M Gatchett (USEPA), was formed in October 2001 to plan and organize an expert workshop Sixty invited international experts participated The meeting was held between June 30 and July 2, 2002 in Baltimore, Maryland, and consisted of five discussion panels — three on prediction and two on verification Each panel was led by a panel leader and a co-leader to address particular technical topics in a designated area A designated graduate fellow, a graduate student whose research was related to these topics, recorded detailed notes for the panel discussions The graduate fellow group was coordinated and supervised by Jada M Kanak (DuPont) Each panel leader, assisted by the co-leader, was responsible for writing a chapter for this book, using the information generated from the panel discussions and the detailed notes recorded by the graduate fellows The prediction chapters were reviewed and edited by Hilary I Inyang, and Lorne G Everett reviewed and edited the verification chapters Calvin Chien had the responsibility for planning, coordinating, and editing the book, ensuring consistency and completeness, and resolving differences in opinions Skip Chamberlain provided technical input and crucial support in working with experts from the national laboratories on critical issues during the preparation of the book David E Daniel (University of Illinois) conducted an initial review of the first draft and provided high-level comments, which were useful in performing subsequent revisions Dr Daniel also wrote the preface for the book, which provides an outstanding introduction of containment technology history and book structure Relevant new information that became available during the period of preparation © 2006 by Taylor & Francis Group, LLC 4040_C000.fm Page xii Wednesday, September 21, 2005 4:38 PM and editing was identified, evaluated, and added to the book to ensure that the information is as up-to-date as possible In addition to organizing and leading the graduate fellow group, Jada Kanak also served as a special technical assistant for book preparation Her detailed and patient efforts in reviewing and checking all of the references, figures, and tables contributed greatly to the quality of this book Ms Kathy O Adams, a long-time DuPont in-house contract technical writer, was responsible for ensuring the grammatical accuracy of the book, and did an excellent job polishing the final draft The team from Florida State University, consisting of Norbert Barszczewski, Sheryl A Grossman, Loreen Y Kollar, J Michael Kuperberg, and Laymon L Gray, were responsible for the workshop planning and contributed greatly to the success of the meeting © 2006 by Taylor & Francis Group, LLC 4040_C000.fm Page xiii Wednesday, September 21, 2005 4:38 PM Preface The containment of buried waste, contaminated soil or groundwater, refers to in situ (in place) management of contaminants in the subsurface Containment is achieved with individual barriers or control technologies that, together, provide a system of engineered control Containment is potentially applicable to any circumstance in which contaminants exist in the subsurface (e.g., uncontrolled landfills or dumps, chemical spills or leaks, pond or lagoon contaminant seepage) and can provide a safe and highly cost-effective mechanism for environmental control Containment is accomplished using physical, hydraulic, or chemical barriers that prevent or control the outward migration of contaminants Containment has come full circle as an acceptable environmental control technology over the past 30 years Prior to the 1980s, containment was virtually the only technology available for managing subsurface contamination Although some wastes were exhumed and treated, more often than not, if the pollution problem was recognized at all, the problem was managed via containment During the 1980s, new environmental regulations emphasized treatment rather than containment Research and development during this time dramatically expanded the portfolio of options available for treating or destroying contaminants at polluted sites Technologies such as vapor extraction, oxidation, bioremediation, surfactant flushing, and heat-induced treatment became viable, though often expensive, treatment alternatives In the 1990s, a dose of reality swung the pendulum back toward containment It became apparent that it was not technically feasible to return contaminated sites to pristine condition Further, as a nation, the United States came to realize that it could not afford, nor did it need, the most sophisticated treatment technology available to manage pollution problems at every site effectively and safely In addition, further research clearly showed that the subsurface has advantages in addressing contamination problems — natural processes such as adsorption and biodegradation can serve to contain or degrade contaminants For certain materials such as radioactive wastes, it became apparent that the exposure risks associated with exhuming contaminants might be far greater than risks associated with managing the wastes in situ with containment Thus, for many reasons, interest in containment was revived in the 1990s Today, containment thrives as a viable environmental management technology, and is often the preferred choice for protecting human health and the environment But a price was paid for putting containment “on hold” during the 1980s, when emphasis was placed on developing sophisticated treatment technologies: little research and development on containment technologies was achieved during © 2006 by Taylor & Francis Group, LLC 4040_C000.fm Page xiv Wednesday, September 21, 2005 4:38 PM this time As interest shifted back toward containment in the 1990s, the industry found itself relying largely on pre-1980s technology Fortunately, in the past 10 years, important advances have occurred in several areas of containment, most notably in the area of permeable reactive barriers, which transform containment barriers into a passive treatment installation In the early 1990s, the need to define the state of the art for containment was understood by three visionary organizations: DuPont, the U.S Environmental Protection Agency, and the U.S Department of Energy The DuPont Corporate Remediation Group (CRG) initiated the trio’s first collaborative effort in 1992 Experts from four nations experts were invited by DuPont to work with a team at the State University of New York at Buffalo to conduct a comprehensive review of the containment technology, the technology gaps, and future direction The product of the work, a 1993 internal report, was published in 1995 by John Wiley & Sons, New York, titled Barrier Containment Technologies for Environmental Remediation Applications, and edited by Ralph R Rumer and Michael E Ryan The principal chapters of the book focused on vertical barriers (walls), bottom barriers (floors), and surface barriers (caps) The three organizations joined again and organized an expert workshop on containment technology in 1995, inviting 115 international experts The book, Assessment of Barrier Containment Technologies: A Comprehensive Treatment for Environmental Remediation Applications, was edited by Ralph R Rumer and James K Mitchell and was published the next year With the rapidly increasing use of barrier technology in remediation, the need for better understanding, prediction, and monitoring of the performance of barriers emerged The trio organized another expert workshop on the topic in 2002, which led to the development of this book The workshop planning committee invited many of the world’s most knowledgeable researchers and practitioners to discuss the current state of the art and debate the appropriate applications and directions for containment The participants then went home and collectively created this book from their knowledge and exchanges This book is essentially a diary of those discussions and assessments, recast into the form of an easily readable, comprehensive book that is rich with discussion and references to literature, as well as further detail on specific topics of interest The first two chapters address prediction issues, Chapters and address monitoring techniques, and Chapter addresses the largely undeveloped field of verification The discussions in the first four chapters address caps, vertical walls, and permeable reactive barriers Chapter 1, “Damage and System Performance Prediction,” sets the stage for how contaminants can get into the subsurface This is an important chapter, because one cannot understand how to contain something unless one knows how the contaminants got into the subsurface in the first place, and how they might spread and threaten the environment without containment This chapter not only describes pathways, but also introduces the essential concept of risk No control technology is without risk Ultimately, a low risk of adverse environmental impact © 2006 by Taylor & Francis Group, LLC 4040_C005.fm Page 342 Wednesday, September 21, 2005 12:28 PM 342 Barrier Systems for Environmental Contaminant Containment & Treatment FIGURE 5.13 Excavation of the colloidal silica barrier showing a major flaw in the slant wall result was that the electroresistivity method used detected the rough shape of the barrier, but could not differentiate anomalies that occurred on fractions of a meter scale In this case, the opening created by the lifted column was 0.3 to 0.6 m high and to m in length Both the SF6 and PFT technology deployments were designed as rudimentary leak tests, but also allowed some analysis to refine flaw location information The primary objective was to test the barrier integrity by injecting tracers inside the barrier and measuring their concentration outside the barrier as a function of time The PFT technology was successful in identifying two locations with weak barrier integrity This tracer technology deployed three different gaseous tracers in three different zones within the barrier confines The east vertical wall showed leakage centered at a depth of 4.5 m below grade approximately 3.6 m into the panel In addition, the multi-tracer technology was able to show that tracer leaked over the top of the barrier, thereby reaching the outside monitoring points without having to go through a flaw in the barrier The actual leak was detected by the tracer oc-PDCH, and the spillover was detected with the tracer PMCH The west (slant) wall also showed evidence of a large leak that was approximately 3.6 m into the panel at a depth of 5.1 m below grade This leak was first detected with the tracer PMCH Leakage also occurred over the top of the panel as evidenced by the tracer oc-PDCH This leak was easily confirmed upon excavation of the barrier and coincided with the misaligned column The PFT © 2006 by Taylor & Francis Group, LLC 4040_C005.fm Page 343 Wednesday, September 21, 2005 12:28 PM Subsurface Barrier Verification 343 technology was also used to estimate the gaseous diffusion coefficient for the grouted panels The SF6 tracer was able to locate the two major leaks, but also detected other possible leaks The possible leaks were, in fact, measurements of tracer spillover at the top of the barrier The tracer technologies appear to be the best suited for leak detection, as they can trace even small (i.e., fractions of an inch) faults in a barrier Although the tracers reveal pathway information, they cannot identify items such as the exact location of a barrier wall, its thickness, or density While identifying if potential contaminant migration paths exist is generally considered the most important factor for subsurface barriers, spatial location of the barrier is important if precise repairs are needed In addition, information on subsurface anomalies that might affect installation (e.g., large rocks, unexpected waste forms), repairs, monitoring, and long-term stability are also important 5.9.3 CASE HISTORY: BARRIER MONITORING AT THE ENVIRONMENTAL RESTORATION DISPOSAL FACILITY (ERDF) The USDOE ERDF located in Hanford, Washington, is a double-lined waste disposal facility that complies with the USEPA’s Minimum Technology Requirements for hazardous waste landfills (Figure 5.14) The design of the disposal cells Environmental restoration disposal facility FIGURE 5.14 ERDF showing Cells and partially full © 2006 by Taylor & Francis Group, LLC 4040_C005.fm Page 344 Wednesday, September 21, 2005 12:28 PM 344 Barrier Systems for Environmental Contaminant Containment & Treatment (including new Cells and 6) call for the following: a primary (upper) liner with a 60-mil textured HDPE sheet, and a secondary (lower) liner with a 60-mil textured HDPE sheet in direct contact with a 0.91-m-thick layer of soil–bentonite admixture in the bottom of each cell Although there is a 100-mil HDPE sheet attached to the sump carrier pipe, it has no containment function (Bechtel Hanford, 1995a,b) The side slopes of the landfill have grades of 3H:1V, while the floors slope toward the sump at grades of 1.5% to 3% Thus, any leachate should drain toward the sumps Under normal conditions, the liner systems outside of the sumps should not experience any standing leachate (pressure head) Within the sumps, submersible pumps remove leachate so that the head pressure on the floor of the sump, except for transient storm conditions, should be less than 0.30 m The low-permeability soil used as the lower component of the secondary liner consists of silty fine sand mixed with approximately 12% bentonite by weight This material was carefully moisture conditioned, placed in lifts, and compacted in the field To establish compaction requirements, a sealed double-ring infiltrometer (SDRI) test was performed prior to construction of the liner in the landfill itself The SDRI verification test is a large-scale simulation of the actual liner and is intended to identify any flaws in construction techniques SDRI results indicated a soil layer permeability of about × 10–8 cm/s The top and bottom leachate collection systems were sampled, and the volumes from each recorded In general, the volume ratio was 100:1 between the upper and lower leachate collection system, and well within the allowable leakage through the primary liner of 175 gallons per day per acre In general, neutron probes and pressure vacuum lysimeters were the barrier verification monitoring tools of choice Everett and Fogwell (2003) conducted a study evaluating barrier verification monitoring for Cells and and subsequent cells at the site Each cell in Figure 5.14 is 21.33 m deep and 152.4 m on a side The cells are arranged in pairs such that they look like one large cell 152.4 m by 304.8 m The National Academy of Engineering held discussions on the subject of barrier monitoring through caps and liners, and the consensus was that any monitoring system that penetrated through the bottom liner would be unacceptable Discussions related to monitoring systems that breach the surface cap were found to be troubling, although the concern related to breaching the cap diminished as the size of the access holes was reduced Neutron access holes in the cap present some problems due to potential preferential flow between the soil and the casing tubing Horizontally installed TDR wave-guides and dissipation probes, however, not present these problems Monitoring below the liners did not appear to be a problem Another possible consideration for monitoring systems is redundancy (i.e., a system that does not rely on only one type of barrier-monitoring system) The following are some possible benefits that redundancy provides: • • A backup system in the event of instrument failure A mechanism to crosscheck instrument accuracies © 2006 by Taylor & Francis Group, LLC 4040_C005.fm Page 345 Wednesday, September 21, 2005 12:28 PM Subsurface Barrier Verification • • • • 345 More confidence in the data A method for identifying false positives It can assist in applying the graded approach utilizing an automated monitoring systems first, and then, if necessary, using a manual system that can include analytical costs Extension of the life expectancy of the entire monitoring system by providing backup systems in the event of instrument failure, particularly for the nonretrievable elements of the monitoring system 5.9.3.1 Study Conclusions The above study indicates that barrier verification monitoring has been used at several commercial landfill sites in the western part of the United States, where arid conditions guarantee the existence of a relatively deep vadose zone These applications of barrier monitoring are generally kept simple and reasonably inexpensive They have generally been employed to give an early warning of leakage and, thus, have resulted in a reduction in required groundwater monitoring Barrier monitoring is used specifically in two general areas of a landfill, beneath the bottom layer of the landfill and in the final cap These correspond to the use of monitoring at two distinct stages of the landfill’s life cycle The first is during the operation of the landfill, while it is being filled and before the final cap is installed The second is during the long-term storage phase, while the final cap is in place Thus, the most appropriate monitoring for the first operational phase is a system installed below the bottom of the landfill, whereas the most appropriate monitoring for the long-term phase is one that monitors the integrity of the cap The above analysis provides potential candidate technologies and approaches for use in either operational or closure applications 5.9.3.2 Study Recommendations Although several reasonable candidates for barrier verification monitoring were evaluated by Everett and Fogwell (2003), some are more applicable at this site than others For all the ERDF cells, when they are closed, barrier monitoring of the caps is strongly recommended (Everett and Fogwell, 2003) The most costeffective approach to use during the operational phase of the landfill, however, would be to instrument new cells with basin lysimeters below the secondary leachate sumps Because of the proven regulatory acceptance, reduced cost considerations, ease of installation, and the ability to collect quantifiable results, a basin lysimeter made up of 100 mil HDPE installed under the secondary sump and beneath the lower compacted low-permeability soil layer in each new cell is the first recommendation This lysimeter would extend 1.52 m beyond the perimeter of the secondary sump, and would be designed with an access pipe that allows the removal of any liquid collected It is important that the basin lysimeter be placed beneath the lowest point of the low-permeability layer In addition to the basin lysimeter, Everett and Fogwell (2003) recommended that access tubes be laid down beneath the secondary barrier liner The access © 2006 by Taylor & Francis Group, LLC 4040_C005.fm Page 346 Wednesday, September 21, 2005 12:28 PM 346 Barrier Systems for Environmental Contaminant Containment & Treatment tubes should extend the full length of each cell with spacing sufficient to allow future cross-borehole tomography Because the tubes would be laid down during construction of the new cells, the costs would be minimal These access tubes will provide access for a variety of instruments and would accommodate new technologies as they are developed Installation at Cells and or future ERDF cells will provide a relatively controlled setting for evaluating the performance and utility of access tubes at future multi-use facilities (Everett and Fogwell, 2003) During the capped long-term storage period of the landfill, instrumentation should be used for maintaining surveillance of the integrity of the barrier cap Noninvasive methods can be used, including lysimeters around the edge of the cap, subsidence monitoring of the cap structure, and tomographic methods for the spatial resolution of possible failure points Invasive methods would entail establishing entry points through the cap into the interior of the landfill In addition to instrumentation of the cap, sensors could be implanted in the body of the landfill in order to monitor its state Also, any tomographic methods at the surface could be combined with the underlying access tubes to give tomographic data on the interior of the landfill Several possible current technologies have been described in this chapter The approach outlined above is consistent with other accepted programs, with additional emphasis placed on access to below the new cells during the operational phase and cap integrity monitoring of final coverings Almost all monitoring methods are expected to be become obsolete or to have some aspect fail over time; thus, it is prudent to consider new technologies and new testing protocols as they are developed, and to allow for the possibility of changing out instrumentation components 5.9.4 VERIFICATION NEEDS The ability to verify barrier integrity is valuable to many government agencies and the commercial sector Verification needs identified at the Baltimore workshop in July 2002 are similar to those identified for PRBs in Table 5.10 The Office of Environmental Management of the USDOE outlined a series of technical targets in a needs document in 2001 Technical Target #5 addresses advanced sustainable containment systems The key word here is sustainable, as containment systems cannot be considered sustainable if the long-term monitoring and stewardship concerns cannot be addressed This is likely the biggest obstacle to closure many USDOE sites will have There are many waste treatment technologies and cover system designs available for final disposition of waste streams, but very little available technology to address long-term monitoring/stewardship issues The Technical Target further states “Properly applied and monitored (bold added for emphasis) physical containment and barriers will remain a central activity in DOE environmental management for the foreseeable future Advancing the science and technology base relatively rapidly is particularly important to closure sites that need to implement and document such systems in the next several years.” © 2006 by Taylor & Francis Group, LLC 4040_C005.fm Page 347 Wednesday, September 21, 2005 12:28 PM Subsurface Barrier Verification 347 In order for a wall or floor to protect the environment, it must remain free of significant holes and flaws throughout its service life Currently, containment system failures are detected by monitoring wells downstream of the waste site Clearly this approach is inefficient, as the contaminants have already migrated from the disposal area before they are detected Methods that indicate early barrier failure (prior to contaminant release) or predict impending failure are needed Early detection of cover failure or pending failure allows repair or replacement to be made before contaminants leave the disposal cell There are clearly two distinct subsets of barriers: cutoff walls/floors and containment barriers The verification needs of these subsets are different The vast majority of cutoff walls are slurry wall installations where the greatest verification need is initial integrity Finding a weak point along the barrier is essential so that the weak spot can be repaired It appears that the present hydraulic gradient-based methods of testing cutoff walls is working well; therefore, further development of advanced monitoring/measurement methods is not warranted For containment barriers, the opposite appears to be true That is, there are no reliable, commercially available integrity/performance measuring technologies available Therefore, this discussion focuses on containment barriers It is important to note that advances in containment barrier verification/monitoring technologies could, in most cases, be readily applied to cutoff walls/floors 5.9.4.1 Adequacy of the Containment Region The barrier must meet the required containment goals The most commonly observed failure for installed walls/floors is incomplete grouting (e.g., misalignment of injection/drill rods, local incomplete grout cure, blockage of the grout injection/delivery by subsurface obstructions) All of these lead to a localized area of the barrier that has reduced containment The imperfection may or may not affect the overall performance of the waste site For instance, a hole in a containment barrier at the top of a wall will not allow significant contaminant migration because horizontal flow in the vadose zone is expected to be minimal and the spread at the top of the barrier will also be minimal However, should the same size hole occur at the bottom of the barrier (particularly in V-shaped containment designs), the containment characteristics of the barrier could be compromised The containment becomes a bathtub with the stopper pulled out, and it can drain quickly Thus, adequacy of the containment requires knowing the size and location of the flaw, and the effect the flaw will have on the overall site performance 5.9.4.2 Long-Term Performance of the Containment The containment must continue to meet the site performance requirements for the lifetime of the barrier As the earlier workshop publications discuss (Rumer and Mitchell, 1995), subsurface barriers are subject to a wide variety of failures or loss of performance Desiccation, chemical attack, geotechnical changes (e.g., earthquakes, subsidence) and many other pathways can lead to reduced © 2006 by Taylor & Francis Group, LLC 4040_C005.fm Page 348 Wednesday, September 21, 2005 12:28 PM 348 Barrier Systems for Environmental Contaminant Containment & Treatment barrier performance When these changes occur, stakeholders must be informed so that corrective actions (if needed) can be implemented Ideally, barrier performance monitoring would be such that stakeholders could predict impending failure and take action prior to contaminants escaping from the containment confines The following are important considerations in long-term monitoring and verification: • • • Monitoring should allow prediction of failure, if possible, rather than detection of failure through detection of contaminants in downstream wells Measured parameters need to feed into risk assessment models so that the effect of changes in performance can be fully understood in terms of protection of and risk to the public and environment Systems should require as little on-site presence as possible The key variable for a containment system is water flux To a lesser degree, volatile contaminant flux is important Because volatiles are not expected to be major components of new waste/waste forms and are likely to be dispersed already at historical sites, water flux remains the key variable (Containment systems are not expected to be installed without some sort of cover system; therefore, the water flux through the site is co-dependent on both the containment barrier and the cover barrier.) While water flux can be a good indicator of changes over time and trends in performance, simply measuring flux is not enough Predictive capabilities are also needed and indicator variables that can be tied to water flux or that give indirect evidence of possible changes in water flux need to be measured Parameters of concern include soil moisture content, permeability (gas/water), precipitation, run off, evapo-transpiration, short-term climate abnormalities, unusual animal intrusion, changes in the containment barrier materials (e.g., plasticity of clays, oxidation of geotextiles), porosity of the barrier, and the condition and location of monitoring devices 5.10 CONCLUSIONS There are numerous opportunities for sensor development and application in the various types of barriers Sensors can be manufactured cheaply and reliably once there is a demand for this type of technology Acceptance by the regulatory community would follow once the benefit and cost-effectiveness of the sensors have been demonstrated A collaborative effort among United States federal agencies would expedite the development of the sensor technologies and should be undertaken immediately The National Research Council (NRC) recently urged the development of sensors for fielded systems for emergency use in countering terrorism, urging that such a program should build on relevant sensor research underway at agencies throughout the federal government because much of the technology is transferable to other disciplines (e.g., hazardous wastes, counterterrorism, medical) (NRC, 2002) © 2006 by Taylor & Francis Group, LLC 4040_C005.fm Page 349 Wednesday, September 21, 2005 12:28 PM Subsurface Barrier Verification 349 A systematic approach to the selection, implementation, and operation of a barrier-monitoring strategy should be adopted Because several alternative technologies, monitoring objectives, and barrier configurations exist, a single technology may not be the most effective for all applications Barriers exposed to environmental and human-induced stresses deteriorate as time progresses from decades to centuries Structural deterioration of some components of a barrier may not always lead to a total functional failure of the system A uniform approach needs to be developed for specifying the failure condition of barriers Monitoring data can be combined with models to forecast future performance levels and/or maintenance requirements Integrated sensor monitoring technologies are expected to play a large part in barrier performance monitoring and verification in addition to being cost-effective methods for long-term monitoring REFERENCES Bechtel Hanford, Inc (1995a) Design Analysis, Construction of W-296 Environmental Restoration Disposal Facility, BHI-00355, Rev 00, Vol 1, U.S Department of Energy Office of Environmental Restoration and Waste Management, June 1995 Bechtel Hanford, Inc (1995b) Design Analysis, Construction of W-296 Environmental Restoration Disposal Facility, BHI-00355, Rev 00, Vol 2, U.S Department of Energy Office of Environmental Restoration and Waste Management, June 1995 Betsill, J.D and Gruebel, R.D (1995) VAMOS The Verification and Monitoring Options Study, Current Research Options for In-Situ Monitoring and Verification of Contaminant Remediation and Containment within the Vadose Zone, Sandia National Laboratory, TTP-AL221107, May 1995 Blowes, D.W and Mayer, K.U (1999) An in situ Permeable Reactive Barrier for the Treatment of Hexavalent Chromium and Trichloroethylene in Ground Water: Vol 3, Mulitcomponent Reactive Transport Modeling, EPA/600/R-99/095c, U.S Environmental Protection Agency, Ada, OK Blowes, D.W., Gillham, R.W., Ptacek, C.J., Puis, R.W., Bennett, T.A., O’Hannesin, S.F., Hanton-Fong, C.J and Bain, J.G (1999a) An in situ Permeable Reactive Barrier for the Treatment of Hexavalent Chromium and Trichloroethylene in Ground Water: Vol 1, Design and Installation, EPA/600/R-99/095a, U.S Environmental Protection Agency, Ada, OK Blowes, D.W., Puis, R.W., Gillham, R.W., Ptacek, C.J., Bennett, T.A., Bain, J.G., HantonFong, C.J and Paul, C.J (1999b) An in situ Permeable Reactive Barrier for the Treatment of Hexavalent Chromium and Trichloroethylene in Ground Water: Vol 2, Performance Monitoring, EPA/600/R-99/095b, U.S Environmental Protection Agency, Ada, OK Borns, D.J (1997) Geomembranes w/Incorporated Fiber Optical Sensors, etc., Proceedings of the International Containment Technology Conference, p 1022 Everett, L.G (1980) Groundwater Monitoring, Genium Publishing Corp., Schenectady, New York, 440 pp Everett, L.G and Fogwell, T.W (2003) Study of the Vadose Zone Monitoring at the Hanford Site, DOE/RL-2003-31, Revision 0, Richland Operations Office, Richland, WA, 53 pp © 2006 by Taylor & Francis Group, LLC 4040_C005.fm Page 350 Wednesday, September 21, 2005 12:28 PM 350 Barrier Systems for Environmental Contaminant Containment & Treatment Everett, L.G., Schmidt, K.D., Tinlin, R.M and Todd, K.D (1976) Monitoring Groundwater Quality: Methods and Costs, U.S Environmental Protection Agency, Las Vegas Everett, L.G., Wilson, L.G and Hoylman, E.W (1984) Vadose Zone Monitoring for Hazardous Waste Sites, Noyes Publications, 358 pp Eykholt, G.R., Elder, C.R and Benson, C.H (1999) Effects of aquifer heterogeneity and reaction mechanism uncertainty on a reactive barrier Journal of Hazardous Materials, 68, 73–99 Fryar, A.E and Schwartz, F.W (1994) Modeling the removal of metals from groundwater by a reactive barrier: experimental results Water Resources Research, 30, 3455–3469 Gillham, R.W and O’Hanneisin, S.F (1994) Enhanced degradation of halogenated aliphatic by zero-valent iron Ground Water, 32, 958–967 Gu, B., Watson, D.B., Phillips, D.H and Liang, L (2002) Biochemical, mineralogical, and hydrological characteristics of an iron reactive barrier used for treatment of uranium and nitrate In Naftz, D.L., Morrison, S.J., Davis, J.A and Fuller, C.C (Eds.), Groundwater Remediation Using Permeable Reactive Barriers, Academic Press, San Diego, pp 305–342 Gupta, N and Fox, T.C (1999) Hydrogeologic modeling for permeable reactive barriers Journal of Hazardous Materials, 68, 19–39 Gupta, N., Sass, B.M., Gavaskar, A.R., Sminchak, J.R., Fox, T.C., Snyder, F.A., O’Dwyer, D and Reeter, C (1998) Hydraulic evaluation of a permeable barrier using tracer tests, velocity measurements, and modeling In Wickramanayake, G.B and Hinchee, R.E (Eds.), Designing and Applying Treatment Technologies: Proceedings of the First International Conference on Remediation of Chlorinated and Recalcitrant Compounds, Vol 1(6), Monterey, CA, 18–21 May, Battelle Press, Columbus, OH, pp 157–162 Hearst, J.R., and Carlson, C.C (1994) A comparison of the moisture gauge and the neutron log in air-filled holes Nuclear Geophysics, 8(2), 165–172 Ho, C.K and Lohrstorfer, C.F (2001) Field test to demonstrate real-time in situ detection of volatile organic compounds, September 19–25, Sandia National Laboratories, Bechtel Nevada Corporation, Las Vegas, NV Hubbard, S., Peterson, J.E., Majer, E.L., Zawislanski, P.T., Roberts, J., Williams, K.H and Wobber, F (1997) Estimation of permeable pathways and water content using tomographic radar data The Leading Edge of Exploration, 16(11), 1623–1628 INEEL (2001) A National Roadmap for Vadose Science and Technology NRC/NAS EM reviews Johnson, T.L and Tratnyek, P.G (1994) A column study of carbon tetrachloride dehalogenation by iron metal In Pasco, W.A (Ed.), Proceedings of the 33rd Hanford Symposium on Health & the Environment In-Situ Remediation: Scientific Basis for Current and Future Technologies, Vol 2, Battelle Pacific Northwest Laboratories, Richland, WA, pp 931–947 Kram, M.L and Keller, A.A (2004a) Complex NAPL site characterization using fluorescence part 2: Analysis of soil matrix effects on the excitation/mission matrix International Journal of Soil and Sediment Contamination, 13, 119–134 Kram, M.L and Keller, A.A (2004b) Complex NAPL site characterization using fluorescence part 3: Detection capabilities for specific excitation sources International Journal of Soil and Sediment Contamination, 13, 135–148 Kram, M.L., Keller, A.A., Rossabi, J and Everett, L (2001a) DNAPL Characterization methods and approaches part 1: Performance comparisons Ground Water Monitoring and Remediation, 21(1), 67–76 © 2006 by Taylor & Francis Group, LLC 4040_C005.fm Page 351 Wednesday, September 21, 2005 12:28 PM Subsurface Barrier Verification 351 Kram, M.L., Keller, A.A., Rossabi, J and Everett, L (2001b) DNAPL Characterization methods and approaches part 2: Cost comparisons Ground Water Monitoring and Remediation, 21(1), 46–61 Kram, M.L., Keller, A.A., Massick, S.M and Laverman, L.E (2004) Complex NAPL site characterization using fluorescence, part 1: Selection of excitation wavelength based on NAPL composition International Journal of Soil and Sediment Contamination, 13, 103–118 Kumthekar, U., Chiou, J.D., Prochaska, K and Benson, C.H (2002) Development of a long-term monitoring system to monitor cover system conditions Spectrum 2002: International Conference on Nuclear and Hazardous Waste Management, American Nuclear Society, Reno, Nevada, August 4–8 Liang L., Korte N., Gu B., Puls R and Reeter, C (2000) Geochemical and microbial reactions affecting long-term performance of in situ “iron barriers.” Advances in Environmental Research, 4, 293–309 Lockhart, C.W., and Roberds, W.J (1996) Worth the risk? Civil Engineering, April, 62–64 Looney, B.B and Falta, R.W (Eds.) (2000a) Vadose Zone Science and Technology Solutions, Vol I, Battelle Press, Columbus, OH, 589 pp Looney, B.B and Falta, R.W (Eds.) (2000b) Vadose Zone Science and Technology Solutions, Vol II, Battelle Press, Columbus, OH, 1540 pp Marcus, D.L and Bond, C (1999) Results of the reactant sand-fracking pilot test and implications for the in situ remediation of chlorinated VOCs and metals in deep and fractured bedrock aquifers Journal of Hazardous Materials, 68, 125–153 Morrison, S.J., Metzler, D.R and Carpenter, C.E (2001) Uranium precipitation in a permeable barrier by progressive irreversible dissolution of zero-valent iron Environmental Sciences Technology, 35, 385–390 Morrison, S.J., Metzler, D.R and Dwyer, B.P (2002) Removal of As, Mn, Se, U, V and Zn from groundwater by zero-valent iron in a passive treatment cell: Reaction progress modeling Journal of Contaminant Hydrology, 56, 99–116 NRC (2003) Making the nation safer: The role of science and technology in countering terrorism, June 2002 Puls, R.W., Paul, C.J and Powell, R.M (1999a) The application of in situ permeable reactive (zero-valent iron) barrier technology for the remediation of chromatecontaminated groundwater: a field test Applied Geochemistry, 14, 989–1000 Puls, R.W., Blowes, D.W and Gillham, R.W (1999b) Long-term performance monitoring for a permeable reactive barrier at the U.S Coast Guard Support Center, Elizabeth City, North Carolina Journal of Hazardous Materials, 68, 109–124 Roh, Y., Lee, S.Y and Elless, M.P (2000) Characterization of corrosions products in the permeable reactive barriers Environmental Geology, 40, 184–194 Rumer, R and Mitchell, J (1995) Assessment of barrier containment technologies: A comprehensive treatment for environmental remediation applications International Containment Technology Workshop, Baltimore, MD, August 29–31 Sass, B.M., Gavaskar, A.R., Gupta, N., Yoon, W.-S., Hicks, J.E., O’Dwyer, D and Reeter, C (1998) Evaluating the Moffett Field permeable barrier using groundwater monitoring and geochemical modeling In Wickramanayake, G.B and Hinchee, R.E (Eds.), Designing and Applying Treatment Technologies: Proceedings of the First International Conference on Remediation of Chlorinated and Recalcitrant Compounds, Vol 1(6), Monterey, CA, 18–21 May, Battelle Press, Columbus, OH, pp 169–175 © 2006 by Taylor & Francis Group, LLC 4040_C005.fm Page 352 Wednesday, September 21, 2005 12:28 PM 352 Barrier Systems for Environmental Contaminant Containment & Treatment Scanlon, B.R., Tyler, S.W and Wierenga, P.J (1997) Hydrologic issues in arid, unsaturated systems and implications for contaminant transport Reviews in Geophysics, 35, 461–490 Smith, S and Nagel, D.J (2003) Nanotechnology-enabled sensors: Possibilities, realities, and applications Sensors, 20(11) Tratnyek, P.G., Johnson, T.L and Schattauer, A (1995) Interfacial phenomena affecting contaminant remediation with zero-valent iron metal Emerging Technologies in Hazardous Waste Management VII, American Chemical Society, Atlanta, GA, pp 589–592 Tratnyek, P.G., Scherer, M.M., Johnson, T.J and Matheson, L.J (2003) Permeable reactive barriers of iron and other zero-valent metals In M.A Tarr (Ed.), Chemical Degradation Methods for Wastes and Pollutants: Environmental and Industrial Applications, Marcel Dekker, New York, pp 371–421 Udd, E (1995) Fiber Optic Smart Structures, Wiley, New York USACE (1997) Design guidance for application of permeable barriers to remediate dissolved chlorinated solvents, Environics Directorate USAF, DG 1110–345-117 USDOE (2002) Long Term Stewardship Science and Technology Roadmap, Office of Long Term Stewardship U.S Department of Energy, INEEL, 201 pp USDOE/CMST (2001) Long Term Monitoring Sensor and Analytical Methods Workshop, June 13–15 USEPA (1997) Permeable Reactive Subsurface Barriers for the Interception and Remediation of Chlorinated Hydrocarbon and Chromium (VI) Plumes in Ground Water, EPA 600-F-97-008, National Risk Management Research Laboratory, Ada, OK, July, 4p USEPA (2002) Field applications on in situ remediation technologies: Permeable reactive barriers, Technology Innovations Office Wilson, L.G., Everett, L.G and Cullen, S.J (Eds.) (1995) Handbook of Vadose Zone Characterization and Monitoring, Lewis, Boca Raton, 730 pp Yabusaki, S., Cantrell, K., Sass, B and Steefel, C (2001) Multicomponent reactive transport in an in situ zero-valent iron cell Environmental Science and Technology, 35, 1493- 1503 © 2006 by Taylor & Francis Group, LLC 4040_book.fm Page 353 Wednesday, September 14, 2005 12:43 PM APPENDIX A Workshop Panels PANEL PREDICTION: MATERIALS STABILITY AND APPLICATION PANEL LEADER Craig H Benson, University of Wisconsin at Madison PANEL CO-LEADER Stephen F Dwyer, Sandia National Laboratories PANEL GRADUATE FELLOW Sazzad Bin-Shafique, University of Wisconsin at Madison PANEL MEMBERS David W Blowes, University of Waterloo David A Carson, United States Environmental Protection Agency, National Risk Management Research Laboratory Peter W Deming, Mueser Rutledge Consulting Engineers Jeffrey C Evans, Bucknell University Glendon W Gee, Battelle Pacific Northwest National Laboratory Laymon L Gray, Florida State University Kathleen E Hain, United States Department of Energy, Idaho Operations Office Stephan A Jefferis, University of Surrey, United Kingdom Mark R Matsumoto, University of California at Riverside Stanley J Morrison, Environmental Sciences Laboratory Scott D Warner, Geomatrix Consultants, Inc John A Wilkens, DuPont PANEL PREDICTION: BARRIER PERFORMANCE PREDICTION PANEL LEADER Charles D Shackelford, Colorado State University 353 © 2006 by Taylor & Francis Group, LLC 4040_book.fm Page 354 Wednesday, September 14, 2005 12:43 PM 354 Barrier Systems for Environmental Contaminant Containment & Treatment PANEL CO-LEADER Jack C Parker, Oak Ridge National Laboratory PANEL GRADUATE FELLOW Alyssa Lanier, University of Wisconsin at Madison PANEL MEMBERS Clifford K Ho, Sandia National Laboratories Richard C Landis, DuPont Eric R Lindgren, Sandia National Laboratories Michael A Malusis, GeoTrans, Inc Mario Manassero, Politecnico, Torino, Italy Greg P Newman, Geo-Slope International Ltd Robert W Puls, United States Environmental Protection Agency, National Risk Management Research Laboratory Timothy M Sivavec, General Electric Brent E Sleep, University of Toronto Terrence M Sullivan, Brookhaven National Laboratory PANEL PREDICTION: DAMAGE AND SYSTEM PERFORMANCE PREDICTION PANEL LEADER Hilary I Inyang, University of North Carolina at Charlotte PANEL CO-LEADER Steven J Piet, Idaho National Engineering and Environmental Laboratory PANEL GRADUATE FELLOW Paul Wachsmuth, University of North Carolina at Charlotte PANEL MEMBERS James H Clark, Vanderbilt University Thomas O Early, Oak Ridge National Laboratory John B Gladden, Westinghouse Savannah River Company Priyantha W Jayawickrama, Texas Tech University W Barnes Johnson, United States Environmental Protection Agency, Office of Solid Waste and Emergency Response Robert E Melchers, University of Newcastle, Australia © 2006 by Taylor & Francis Group, LLC 4040_book.fm Page 355 Wednesday, September 14, 2005 12:43 PM Workshop Panels 355 V Rajaram, Black and Veatch Corporation W Jody Waugh, United States Department of Energy, Environmental Sciences Laboratory Thomas F Zimmie, Rensselaer Polytechnic Institute PANEL VERIFICATION: AIRBORNE AND SURFACE/GEOPHYSICAL METHODS PANEL LEADER Ernest L Majer, Lawrence Berkeley National Laboratory PANEL CO-LEADER David P Lesmes, Boston College PANEL GRADUATE FELLOW Marcel Belaval, Boston College PANEL MEMBERS Randolf J Cumbest, Westinghouse Savannah River Company William E Doll, Oak Ridge National Laboratory Edward Kavazanjian, Jr., GeoSyntec Consultants John D Koutsandreas, Florida State University John W Lane, United States Geological Survey Lee D Slater, University of Missouri at Kansas City Anderson L Ward, Battelle Pacific Northwest National Laboratory Chester J Weiss, Sandia National Laboratories PANEL VERIFICATION: SUBSURFACE-BASED METHODS PANEL LEADER David J Borns, Sandia National Laboratories PANEL CO-LEADER Carol Eddy-Dilek, Westinghouse Savannah River Company PANEL GRADUATE FELLOW Matthew C Spansky, Westinghouse Savannah River Company © 2006 by Taylor & Francis Group, LLC 4040_book.fm Page 356 Wednesday, September 14, 2005 12:43 PM 356 Barrier Systems for Environmental Contaminant Containment & Treatment PANEL MEMBERS William R Berti, DuPont George K Burke, Hayward Baker, Inc Bruce Davis, National Aeronautics and Space Administration John H Heiser, Brookhaven National Laboratory Diana J Hollis Puglisi, Los Alamos National Laboratory John B Jones, United States Department of Energy, Nevada Operations Office John D Koutsandreas, Florida State University William E Lowry, Science and Engineering Associates, Inc Horace K Moo-Young, Jr., Villanova University Michael G Serrato, Westinghouse Savannah River Company © 2006 by Taylor & Francis Group, LLC ... trademarks, and are used only for identification and explanation without intent to infringe Library of Congress Cataloging-in-Publication Data Barrier systems for environmental contaminant containment and. .. range of barrier applications available now and in the future, there is a need for improved capacity to predict containment barrier damage and system performance Damage and system performance... 12:43 PM Barrier Systems for Environmental Contaminant Containment & Treatment framework should incorporate nodes to which pre-failure performance models can be linked 1.2.1 CONCEPTS AND ANALYTICAL