Groundwater And Subsurface Remediation

The complex topic of in-situ subsurface remediation technologies has been ad dressed at an international symposium at the Universitat Stuttgart on September 26 and 27, 1995, on the occasion of the inauguration of the research facility VEGAS (Versuchseinrichtung zur Grundwasser- und Altlastensanierung). The results are contained in this book with 22 contributions from leading experts in the field from Europe and North America. The book illustrates the role of large-scale experiments in groundwater and subsurface remediation research. The subtopics address the various links between conventional laboratory experiments, technology-scale experiments and field-site studies, showing the contribution of large-scale experiments to bridging the gap between small-scale investigations and large-scale field investigations (upscaling). The interdisciplinary nature of the problems requires a multidisciplinary approach. Therefore, the idea has been followed to bring together the various disciplines in volved in the different aspects and facets of subsurface flow, transport and trans as hydraulics and hydrology, physics, formation, involving such diverse disciplines chemistry, microbiology, geology, industrial, chemical and hydraulic engineering, mathematics and hydroinformatics. The individual contributions from these di versified fields address the subject from different angles in an attempt to form a coherent picture of the various aspects of the complex problems of subsurface remediation. The focus is on research approaches and strategies with respect to the development of new and improved technologies and to the role of large-scale experiments in research and application.

The complex topic of in-situ subsurface remediation technologies has been ad dressed at an international symposium at the Universitat Stuttgart on September 26 and 27, 1995, on the occasion of the inauguration of the research facility VEGAS (Versuchseinrichtung zur Grundwasser- und Altlastensanierung). The results are contained in this book with 22 contributions from leading experts in the field from Europe and North America. The book illustrates the role of large-scale experiments in groundwater and subsurface remediation research. The subtopics address the various links between conventional laboratory experiments, technology-scale experiments and field-site studies, showing the contribution of large-scale experiments to bridging the gap between small-scale investigations and large-scale field investigations (upscaling). The interdisciplinary nature of the problems requires a multidisciplinary approach. Therefore, the idea has been followed to bring together the various disciplines in volved in the different aspects and facets of subsurface flow, transport and trans as hydraulics and hydrology, physics, formation, involving such diverse disciplines chemistry, microbiology, geology, industrial, chemical and hydraulic engineering, mathematics and hydroinformatics. The individual contributions from these di versified fields address the subject from different angles in an attempt to form a coherent picture of the various aspects of the complex problems of subsurface remediation. The focus is on research approaches and strategies with respect to the development of new and improved technologies and to the role of large-scale experiments in research and application.

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.

This volume is meant to provide the practitioner with information on the natural mixing processes occurring in aquifers as well as to describe basic strategies that can be implemented to enhance mixing in particular cases. For example, when it comes to mixing miscible liquids, one can speed up mixing in the formation by manipulating the flow such as through the use of recirculation wells. Furthermore, much of the mixing can be achieved partially within recirculation wells themselves, where contaminated water is admixed with additives, volatile products may be removed through a vapor mass exchanger, etc. Thus, adding mixing wells can significantly increase the performance of the delivery and mixing system and speed up the process of remediation.

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.

As we transition into the 21st century, it is apparent that this is an exciting time for environmental engineers and scientists studying remediation technologies. There has been a rapid development of new ways to clean-up polluted groundwater. Research activities of the past and next 10 years will have a dramatic impact on the quality of the subsurface environment for the next century. In 20, or even 10 years from now, our approach to subsurface remediation will probably be vastly different than it is today. Many of the emerging technologies presented in this book will form the basis of standard remediation practices of the future. Physicochemical Groundwater Remediation presents detailed information on multiple emerging technologies for the remediation of the contaminated subsurface environment. All of these technologies apply our knowledge of physical and chemical processes to clean up ground water and the unsaturated zone, and many (if not all) of these emerging technologies will help define standard practices in the future. These technologies include in situ sorptive and reactive treatment walls, surfactant-enhanced aquifer remediation, optimization analyses for remediation system design, chemical, electrochemical, and biochemical remediation processes, and monitored natural attenuation. You will learn how palladium catalyzes the dehalogenation of chlorinated solvents. You will find out how barometric pumping can naturally remove significant quantities of volatile organic pollutants from shallow ground water and the unsaturated zone. You can learn about mobilizing non-aqueous phase liquids (NAPLs) without risking significant downward migration of the NAPL. You can find out how processes such as electroosmosis and electromigration can be exploited for groundwater remediation purposes and how zero-valent iron and zeolite treatment walls can be used in situ to treat and control contaminant plume migration. Contributors to this book are experts in groundwater remediation processes, and they represent industry, consulting, academia, and government. If your work involves the clean up of contaminated soil and groundwater, this book is an essential reference to keep you up to date on the most promising new developments in remediation research.

Across the United States, thousands of hazardous waste sites are contaminated with chemicals that prevent the underlying groundwater from meeting drinking water standards. These include Superfund sites and other facilities that handle and dispose of hazardous waste, active and inactive dry cleaners, and leaking underground storage tanks; many are at federal facilities such as military installations. While many sites have been closed over the past 30 years through cleanup programs run by the U.S. Department of Defense, the U.S. EPA, and other state and federal agencies, the remaining caseload is much more difficult to address because the nature of the contamination and subsurface conditions make it difficult to achieve drinking water standards in the affected groundwater. Alternatives for Managing the Nation's Complex Contaminated Groundwater Sites estimates that at least 126,000 sites across the U.S. still have contaminated groundwater, and their closure is expected to cost at least $110 billion to $127 billion. About 10 percent of these sites are considered "complex," meaning restoration is unlikely to be achieved in the next 50 to 100 years due to technological limitations. At sites where contaminant concentrations have plateaued at levels above cleanup goals despite active efforts, the report recommends evaluating whether the sites should transition to long-term management, where risks would be monitored and harmful exposures prevented, but at reduced costs.