Leaching Assessment for Disposal and Beneficial Use of Wastes and Secondary Materials
 
David S. Kosson, Ph.D.
Professor and Chair of Civil and Environmental Engineering
Professor of Chemical Engineering and Professor of Earth and Environmental Sciences
Vanderbilt University
Nashville, TN  37235

Abstract:
Leaching is the process of constituent release from a solid material into solution. For environmental systems, leaching is a mechanism by which constituents of potential concern may be released from solid materials, such as wastes or secondary materials, when contacted by water through infiltration, contact with groundwater or other mechanisms. Leaching often is the primary mechanism of environmental impact from disposal or beneficial use of secondary materials. Traditionally, leaching assessment has been carried out using laboratory tests designed to mimic specific field conditions. However, this approach requires a large number of test methods to consider a range of potential management scenarios and does not account for varying field conditions. An alternate approach has been proposed that measures fundamental leaching characteristics of a material and then uses the results in combination with geochemical equilibrium and mass transfer models to estimate release under field conditions. In this manner, a single data set can be used to compare multiple management scenarios. This approach currently is being transferred into use through the development of standard methods and guidance by USEPA and incorporation into regulation by the European Union.

About the Lecturer:
Professor Kosson is Professor and Chairman of Civil and Environmental Engineering at Vanderbilt University in Nashville, TN, where he is also Professor of Chemical Engineering and Professor of Earth and Environmental Sciences. Professor Kosson’s research focuses on contaminant mass transfer applied to groundwater, soil, sediment and waste systems, as well as management of nuclear wastes and restoration of the Department of Energy’s nuclear complex. Professor Kosson’s research on leaching of contaminants from wastes and construction materials is currently providing the foundation for environmental regulation of these materials at USEPA, The Netherlands Ministry of Environment and the European Union’s Directorate General for the Environment. Professor Kosson is the Co-PI of the Consortium for Risk Evaluation with Stakeholder Participation (CRESP), a multi-university organization carrying out basic and applied research to improve the environmental restoration of the U.S. Department of Energy’s complex to produce and maintain nuclear materials. Professor Kosson also has provided expertise and leadership for the National Academies of Engineering and Science, as advisory to the Department of Defense, for more than a decade on demilitarization of the chemical weapons in the United States and abroad.