Dual Domain Transport Impacts on Projected Groundwater Remediation

Fitzgerald, Robert H.

Dual Domain Transport Impacts on Projected Groundwater Remediation

Tuesday, May 6, 2014: 3:00 p.m.

Platte River Room (Westin Denver Downtown)

Kristina K. Masterson, P.E., D.WRE , CDM Smith, Cambridge, MA

Robert H. Fitzgerald, P.E. , CDM Smith, Cambridge, MA

Contaminant plume “tailing” is a commonly used description of a groundwater cleanup that proceeds slower than expected, based on routine contaminant transport analysis. One cause of tailing is slow diffusion of dissolved contamination from lower permeability portions of an aquifer into higher permeability zones that may continue for a long time after remediation of the source. Diffusive exchange of contaminant mass may occur between a relatively low permeability rock matrix and high permeability fractures in a bedrock aquifer or between silt or clay lenses and adjacent high permeability sandy fractions within a heterogeneous overburden aquifer.

Using a dual domain transport algorithm developed in DYNSYSTEM, mass transport simulations were conducted for an industrial remediation site to evaluate the potential impacts of dual domain transport on the duration of groundwater remediation and to inform remediation operation cost projections.

Test simulations of historical plume development were used to estimate an appropriate range of dual domain parameter values for future projection simulations. Projection simulation results indicated that factoring in matrix diffusion has the potential to more than double the estimated time required to achieve the remedial objective and system shutdown compared with the original estimate based on conventional transport modeling.

Kristina K. Masterson, P.E., D.WRE, CDM Smith, Cambridge, MA

Kristina Masterson is a water resources engineer who specializes in groundwater flow and contaminant transport model simulation analysis. She has conducted groundwater flow and mass transport modeling studies for site environmental assessment, remediation investigation and design, remediation performance evaluation, and water resources management projects. During the 20 years that she has worked in the water resources engineering field, Masterson has successfully applied numerical groundwater flow and mass transport models to study groundwater flow patterns and contaminant mass transport characteristics in many different hydrogeological settings.

Robert H. Fitzgerald, P.E., CDM Smith, Cambridge, MA

Robert Fitzgerald is a Senior Groundwater Modeler who has been responsible for numerous studies of groundwater flow and dissolved and separate phase contaminant transport in aquifers. He also has extensive experience in hydrology, hydraulics, and water resources management, emphasizing the application of computer simulation models. Fitzgerald has been responsible for the use of models in analyzing and developing programs for groundwater management and remediation, flood alleviation, reservoir yield augmentation, and water quality assessment.