The environmental problems associated with DNAPLs (dense, nonaqueous-phase liquids) are well known—extremely difficult to locate; small amounts contaminate large volumes; conventional groundwater extraction technologies do not work; and restoration of DNAPL sites to drinking water standards or maximum contaminant levels is considered unattainable. DNAPLs can be treated by implementing one of several or a combination of technologies. Despite the ever-increasing number of field applications of DNAPL removal technologies, many unanswered questions remain regarding the effectiveness of these technologies and how best to measure their performance with respect to site-specific remedial objectives.
This training addresses specific issues dealing with monitoring the performance of various DNAPL source zone remediation technologies. It is based on ITRC's Strategies for Monitoring the Performance of DNAPL Source Zone Remedies (DNAPLs-5, 2004). Performance is discussed in terms of effective and efficient progress toward the project goals. Elements of a robust performance monitoring program are described, including the need to establish appropriate performance goals and metrics well in advance. The applicability and limitations of various performance metrics, including the concept of mass flux, are discussed. Because of these limitations, a converging lines of evidence approach to performance assessment is stressed. While some issues pertaining to DNAPL fate and transport are covered in the document, participants are encouraged to review the material presented in the UK Environment Agency's Illustrated Handbook of DNAPL Fate and Transport in the Subsurface prior to taking the course.