Evaluation of an upscaled model for DNAPL dissolution kinetics in heterogeneous aquifers

Estimates of contaminant fluxes from DNAPL sources as a function of time and DNAPL mass reduction are important to assess the long-term sustainability and costs of monitored natural attenuation and to determine the benefits of partial source removal. We investigate the accuracy of the upscaled mass transfer function (MTF) proposed by Parker and Park [Parker JC, Park E. Modeling field-scale dense nonaqueous phase liquid dissolution kinetics in heterogeneous aquifers. WRR 2004;40:W05109] to describe field-scale dissolved phase fluxes from DNAPL sources for a range of scenarios generated using high-resolution 3-D numerical simulations of DNAPL infiltration and long-term dissolved phase transport. The results indicate the upscaled MTF is capable of accurately describing field-scale DNAPL dissolution rates as a function of time. For finger-dominated source regions, an empirical mass depletion exponent in the MTF takes on values greater than one which results in predicted mass flux rates that decrease continuously with diminishing DNAPL mass over time. Lens-dominated regions exhibit depletion exponents less than one, which results in more step-function like mass flux versus time behavior. Mass fluxes from DNAPL sources exhibiting both lens- and finger-dominated subregions were less accurately described by the simple MTF, but were well described by a dual-continuum model of the same form for each subregion. The practicality of calibrating a dual-continuum model will likely depend on the feasibility of obtaining spatially resolved field measurements of contaminant fluxes or concentrations associated with the subregions using multilevel sampling or some other means.

[1]  George F. Pinder,et al.  An experimental study of complete dissolution of a nonaqueous phase liquid in saturated porous media , 1994 .

[2]  T. Phelan,et al.  Influence of textural and wettability variations on predictions of DNAPL persistence and plume development in saturated porous media , 2004 .

[3]  T H Illangasekare,et al.  A review of NAPL source zone remediation efficiency and the mass flux approach. , 2004, Journal of hazardous materials.

[4]  S. Powers,et al.  Mass transfer correlations for nonaqueous phase liquid dissolution from regions with high initial saturations , 2003 .

[5]  James F. Pankow,et al.  Dissolution of dense chlorinated solvents into groundwater. 3. Modeling contaminant plumes from fingers and pools of solvent , 1992 .

[6]  Clayton V. Deutsch,et al.  Geostatistical Software Library and User's Guide , 1998 .

[7]  Bernard H. Kueper,et al.  A field experiment to study the behavior of tetrachloroethylene in unsaturated porous media , 1992 .

[8]  Cass T. Miller,et al.  Dissolution of Trapped Nonaqueous Phase Liquids: Mass Transfer Characteristics , 1990 .

[9]  T. Illangasekare,et al.  Effect of groundwater flow dimensionality on mass transfer from entrapped nonaqueous phase liquid contaminants , 2000 .

[10]  Cass T. Miller,et al.  The influence of mass transfer characteristics and porous media heterogeneity on nonaqueous phase dissolution , 1996 .

[11]  Jack C. Parker,et al.  A parametric model for constitutive properties governing multiphase flow in porous media , 1987 .

[12]  Cass T. Miller,et al.  Multiphase flow and transport modeling in heterogeneous porous media: challenges and approaches , 1998 .

[13]  J. Jawitz,et al.  Comment on “Steady state mass transfer from single‐component dense nonaqueous phase liquids in uniform flow fields” by T. C. Sale and D. B. McWhorter , 2003 .

[14]  David Redman,et al.  A Field Experiment to Study the Behavior of Tetrachloroethylene Below the Water Table: Spatial Distribution of Residual and Pooled DNAPL , 1993 .

[15]  Eungyu Park,et al.  Modeling field‐scale dense nonaqueous phase liquid dissolution kinetics in heterogeneous aquifers , 2004 .

[16]  J. Geller,et al.  Mass Transfer From Nonaqueous Phase Organic Liquids in Water-Saturated Porous Media. , 1993, Water resources research.

[17]  R. Carsel,et al.  Developing joint probability distributions of soil water retention characteristics , 1988 .

[18]  Jason I. Gerhard,et al.  Variability of point source infiltration rates for two‐phase flow in heterogeneous porous media , 1995 .

[19]  Susan E. Powers,et al.  An experimental investigation of nonaqueous phase liquid dissolution in saturated subsurface systems: Transient mass transfer rates , 1992 .

[20]  Ronald W. Falta,et al.  Modeling sub‐grid‐block‐scale dense nonaqueous phase liquid (DNAPL) pool dissolution using a dual‐domain approach , 2003 .

[21]  T. Sale,et al.  Steady state mass transfer from single‐component dense nonaqueous phase liquids in uniform flow fields , 2001 .

[22]  Linda M. Abriola,et al.  The influence of field-scale heterogeneity on the surfactant-enhanced remediation of entrapped nonaqueous phase liquids , 2000 .