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IMPACTS OF DNAPL MASS DEPLETION ON SOURCE STRENGTH
Citation:
Wood*, A L., M. D. Annable, C G. Enfield*, R. W. Falta, M. N. Goltz, J. W. Jawitz, AND P. S. Rao. IMPACTS OF DNAPL MASS DEPLETION ON SOURCE STRENGTH. Presented at 2003 SERDP Symposium, Washington, DC, 12/2-4/2003.
Description:
Implementation of remediation technologies at DNAPL contaminated sites has shown that large quantities of contaminants can be removed or degraded using in-situ heating, flushing or oxidation. The rate and magnitude of DNAPL removal is dependent upon site-specific and technology-specific factors. Field results have demonstrated that the efficiency of DNAPL depletion often decays exponentially with increasing mass removed. Thus, it may be neither practical nor economically feasible to remove all of the DNAPL mass from the source zone. With finite resources, one needs to know the maximum amount of DNAPL mass that can be left in the source zone while being protective of human health and the environment.
The primary objective of this SERDP- and EPA-funded project is to develop a scientifically defensible approach for assessing the long-term environmental impacts of DNAPL removal from source zones. The fundamental premise for the project is that contaminant flux from the source, rather than contaminant concentration, should be used as the basis for evaluating the effectiveness of remediation. Contaminant flux is defined as the contaminant mass leaving the source zone across a control plane orthogonal to the mean groundwater flow. Thus, the technical focus of the project is to (1) characterize the relationships between DNAPL mass reduction, contaminant mass flux, and plume behavior, and (2) to use this information to develop a strategy for assessing the benefits of DNAPL source remediation. An integrated three-pronged approach, comprised of laboratory experiments, field observations and numerical simulations, is being used. This approach allows the evaluation of a wide range of hydrogeologic, contaminant and remediation scenarios.