2005 Progress Report: Novel Methods for Laboratory Measurement of Transverse Dispersion in Porous Media

EPA Grant Number: R828772C013
Subproject: this is subproject number 013 , established and managed by the Center Director under grant R828772
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).

Center: HSRC (2001) - Western Region Hazardous Substance Research Center for Developing In-Situ Processes for VOC Remediation in Groundwater and Soils
Center Director: Semprini, Lewis
Title: Novel Methods for Laboratory Measurement of Transverse Dispersion in Porous Media
Investigators: Kitanidis, Peter K. , Criddle, Craig C.
Institution: Stanford University
EPA Project Officer: Lasat, Mitch
Project Period: September 1, 2001 through August 31, 2006
Project Period Covered by this Report: September 1, 2004 through August 31, 2005
RFA: Hazardous Substance Research Centers - HSRC (2001) RFA Text |  Recipients Lists
Research Category: Land and Waste Management , Hazardous Waste/Remediation

Objective:

(1) Develop, refine, and critically evaluate novel methods for the laboratory measurement of transverse dispersion in homogeneous isotropic unconsolidated porous media; (2) develop experimental protocols and methods of data analysis; (3) independently verify the accuracy of the new methods; and (4) perform extensive experiments to determine relations of transverse dispersivity with conductivity, longitudinal dispersivity, mean grain size, degree of non-uniformity, etc.

Progress Summary:

Rationale

Transverse dispersion in porous media measures the rate of spreading of a solute in the direction perpendicular to flow. Pore-scale transverse dispersion is widely accepted as playing a dominant role in determining the actual rate of dilution of solutes and mixing of reactants in porous media. For example, consider a long plume of contaminants emanating from a constant source. The rate of intrinsic remediation is determined by the rate of transverse mixing of contaminants in the plume with reactants from the surrounding groundwater. The rate may be primarily determined by the value of the transverse dispersion coefficient. Better understanding of transverse dispersion would ultimately improve our understanding of diffusion-limited processes, such as intrinsic remediation. Despite its importance, transverse dispersion remains insufficiently understood.

Approach

Part of the difficulty has been the lack of accurate and efficient methods for laboratory measurements. In most existing methods for the determination of transverse dispersion, the measured quantity is proportional to the dispersion coefficient, and thus small and swamped by experimental error. However, we have developed new methods for the measurement of local transverse dispersion in isotropic porous media based on a helical and a cochlea-like device. The idea is to perform an experiment similar to the tracer test through a laboratory column packed with a porous medium and to measure the breakthrough curve; however, the objective is not to determine the column-scale longitudinal dispersion but the transverse dispersion. The principle is to induce shear flow inside the device that creates strong longitudinal dispersion in the observed breakthrough curve; transverse mixing tends to negate the effects of shear flow and thus reduce the observed column-scale longitudinal dispersion. Then, from the spreading of the observed breakthrough curve, we can estimate the unknown, the pore-scale transverse dispersion. The measured quantity varies inversely with the transverse dispersion coefficient.

Status

The project is near completion and a Ph.D. dissertation has been submitted that will serve as the final report. Highlights of the dissertation: We discuss instrumentation and tracers that we used to obtain experimental concentration breakthrough curves. We describe the numerical simulation and parameter estimation methods used to analyze the experimental data. We discuss the results and describe the relative advantages of each device, instrument, and methodology that we have used to estimate transverse dispersivity. Perhaps the most noteworthy conclusions of this research are that the results from the two devices, helix and cochlea, are in agreement and that the ratio of transverse dispersivity to longitudinal dispersivity that we estimate agrees with the higher ratios reported in the literature.


Journal Articles on this Report : 2 Displayed | Download in RIS Format

Other subproject views: All 6 publications 2 publications in selected types All 2 journal articles
Other center views: All 158 publications 63 publications in selected types All 60 journal articles
Type Citation Sub Project Document Sources
Journal Article Luo J, Kitanidis PK. Fluid residence times within a recirculation zone created by an extraction-injection well pair. Journal of Hydrology 2004;295(1-4):149-162. R828772 (2003)
R828772 (2004)
R828772 (Final)
R828772C013 (2005)
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  • Journal Article Luo J, Cirpka OA, Kitanidis PK. Temporal-moment matching for truncated breakthrough curves for step or step-pulse injection. Advances in Water Resources 2006;29(9):1306-1313. R828772 (Final)
    R828772C013 (2005)
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  • Relevant Websites:

    http://wrhsrc.oregonstate.edu/ Exit

    Progress and Final Reports:

    Original Abstract
  • 2002
  • 2003
  • 2004 Progress Report
  • Final

  • Main Center Abstract and Reports:

    R828772    HSRC (2001) - Western Region Hazardous Substance Research Center for Developing In-Situ Processes for VOC Remediation in Groundwater and Soils

    Subprojects under this Center: (EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
    R828772C001 Developing and Optimizing Biotransformation Kinetics for the Bio- remediation of Trichloroethylene at NAPL Source Zone Concentrations
    R828772C002 Strategies for Cost-Effective In-situ Mixing of Contaminants and Additives in Bioremediation
    R828772C003 Aerobic Cometabolism of Chlorinated Aliphatic Hydrocarbon Compounds with Butane-Grown Microorganisms
    R828772C004 Chemical, Physical, and Biological Processes at the Surface of Palladium Catalysts Under Groundwater Treatment Conditions
    R828772C005 Effects of Sorbent Microporosity on Multicomponent Fate and Transport in Contaminated Groundwater Aquifers
    R828772C006 Development of the Push-Pull Test to Monitor Bioaugmentation with Dehalogenating Cultures
    R828772C007 Development and Evaluation of Field Sensors for Monitoring Bioaugmentation with Anaerobic Dehalogenating Cultures for In-Situ Treatment of TCE
    R828772C008 Training and Technology Transfer
    R828772C009 Technical Outreach Services for Communities (TOSC) and Technical Assistance to Brownfields Communities (TAB) Programs
    R828772C010 Aerobic Cometabolism of Chlorinated Ethenes by Microorganisms that Grow on Organic Acids and Alcohols
    R828772C011 Development and Evaluation of Field Sensors for Monitoring Anaerobic Dehalogenation after Bioaugmentation for In Situ Treatment of PCE and TCE
    R828772C012 Continuous-Flow Column Studies of Reductive Dehalogenation with Two Different Enriched Cultures: Kinetics, Inhibition, and Monitoring of Microbial Activity
    R828772C013 Novel Methods for Laboratory Measurement of Transverse Dispersion in Porous Media
    R828772C014 The Role of Micropore Structure in Contaminant Sorption and Desorption