Grantee Research Project Results
1997 Progress Report: Investigation of the Entrapment and Surfactant Enhanced Recovery of Nonaqueous Phase Liquids in Heterogeneous Sandy Media
EPA Grant Number: R825409Title: Investigation of the Entrapment and Surfactant Enhanced Recovery of Nonaqueous Phase Liquids in Heterogeneous Sandy Media
Investigators: Abriola, Linda M. , Pennell, Kurt D. , Dane, Jacob H.
Institution: University of Michigan , Auburn University Main Campus , Georgia Institute of Technology
EPA Project Officer: Hahn, Intaek
Project Period: November 1, 1996 through October 31, 1999
Project Period Covered by this Report: November 1, 1996 through October 31, 1997
Project Amount: $449,938
RFA: Environmental Fate and Treatment of Toxics and Hazardous Wastes (1996) RFA Text | Recipients Lists
Research Category: Hazardous Waste/Remediation , Land and Waste Management , Safer Chemicals
Objective:
The primary objectives of this research project are: 1) to investigate the influence of scale and formation heterogeneity on the entrapment and surfactant-enhanced recovery of NAPLs in two-phase sandy aquifer systems; and 2) to refine and validate numerical simulators which may be used for the design and prediction of SEAR performance at the field scale.Progress Summary:
Progress has been made in each of the four task areas: (1) the measurement of flow and transport parameters including the measurement of composition dependent fluid viscosity, measurement of PCE solubilization curves, and evaluation of dispersion in 2D tanks containing heterogeneous sand distributions; (2) the refinement and adaptation of numerical models for two-phase NAPL migration and entrapment, and for surfactant-enhanced recovery; (3) the experimental measurement of NAPL infiltration and entrapment processes in small and large scale 2D tanks, experimental investigation of partitioning tracer tests in one and two dimensional systems for quantifying NAPL volumes, and preliminary modeling simulations; and (4) preliminary experimental and numerical investigation of surfactant enhanced solubilization of PCE in 2D sank tanks.Accomplishments And Research Results:
Laboratory studies have been conducted to measure and characterize fundamental surfactant and NAPL properties which affect transport processes and SEAR performance. Viscosity measurements were conducted for water, dodecane, and two surfactant solutions. Solubility curves were produced to quantify PCE solubilization in Tween 80 solutions. Experiments were conducted in a large scale, extensively monitored two-dimensional sand tank to evaluate the dispersivity distribution in heterogeneous porous medium. Results indicate that dispersivity values determined under field conditions are not only subject to heterogeneities but also to density effects.
Experiments in 2D laboratory sand tanks were conducted to investigate the impact of macroscale heterogeneities on two-phase NAPL migration and entrapment. The macro-heterogeneities were observed to impart considerable influence on the PCE migration pathway. PCE was not observed to enter the low permeability zones, instead flowing around and pooling over the sand lenses. The migration of PCE in the 2D sand box was simulated with a numerical multiphase flow model. Numerical predictions of the PCE distribution are qualitatively similar to visual observations of PCE migration behavior.
Laboratory experiments were conducted in one-dimensional soil columns and 2D sand tanks to evaluate the use of partitioning tracers for estimating PCE volume. Effluent breakthrough curves have been quantified for isopropanol, 2,3-dimethyl-2-butanol, hexanol, and potassium iodide in the 1D studies. Effluent samples of isopropanol, hexanol, and 2,3 DMB have been collected from the 2D experiments and are currently being analyzed.
Laboratory experiments were conducted to investigate the solubilization of PCE by a 4% Tween 80 solution in the 2D heterogeneous system. Excellent SEAR performance was observed with the majority of residual PCE removed within five pore volumes. Effluent data indicate strong mass transfer limitations control the rate of PCE solubilization. Simulation of the PCE solubilization experiment is being conducted to evaluate mass transfer limitations.
Future Activities:
Future measurements of flow and transport parameters will be conducted, including fluid density and interfacial tension. Effluent samples obtained during the displacement and partitioning tracer experiments in the large sand tank will be analyzed by GC analysis for alcohol concentrations.Moment analysis will be used to evaluate residual NAPL saturations and solute transport in both column and box experiments. The results for the large tank experiments will then be compared with those obtained with the gamma radiation system. Laboratory experiments in 2D laboratory sand tanks will continue for the investigation of NAPL infiltration processes and SEAR performance. Work will continue on the refinement and enhancement of numerical models for simulation PCE migration and SEAR processes. Numerical investigations will focus on the evaluation of numerical and parametric requirements for accurate simulation of NAPL migration and entrapment processes, and on the evaluation of mass transfer limitations in the 2D solubilization experiments.
Journal Articles:
No journal articles submitted with this report: View all 23 publications for this projectSupplemental Keywords:
RFA, Scientific Discipline, Toxics, Waste, Ecosystem Protection/Environmental Exposure & Risk, Remediation, Environmental Chemistry, HAPS, Chemistry, Fate & Transport, Hazardous Waste, Hazardous, Environmental Engineering, SEAR technology, fate and transport, fate and transport , NAPL, contaminant transport, surfactant enhanced aquifer remediation, transport contaminants, dual energy gamma radiation system, chemical contaminants, pump and treat systems, geochemistry, saturated porous media, ecological impacts, hazardous chemicals, assessment methods, heterogenous sandy media, NAPLs, porous mediaProgress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.