Innovative Approaches for the Characterization of Subsurface Properties and Contamination, and Enhan

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Innovative Approaches for the Characterization of
Subsurface Properties and Contamination, and
Enhanced-Removal of Immiscible Liquid in the
Subsurface

• Geoffrey R. Tick
• Contaminant Transport Group
• Department of Geological Sciences
• The University of Alabama
• February 14, 2007
• BWEA-EI Meetings Series Hydrology

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Light NAPL
Spill
Residual Contaminants
Non-Aqueous Phase
Vadose Zone
Liquid Contaminants
Capillary Fringe
Water Table
Dissolved Contaminants
Bedrock
Bedrock
Groundwater Flow
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Dense NAPL
Spill
Residual Contaminants
Vadose Zone
Non-Aqueous Phase
Liquid Contaminants
Capillary Fringe
Water Table
Dissolved
Contaminants
Bedrock
Groundwater Flow
Bedrock
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Characterize the Porous Media
Moisture Content? Tortuosity? Physical Structure?
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Vadose Zone
Capillary Fringe
Water Table
Bedrock
Groundwater Flow
Bedrock
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Problem With NAPL

• Nonaqueous phase liquid (NAPL) contamination is
  widespread
• (e.g., VOCs, solvents, petroleum hydrocarbons,
  coal tars)
• NAPL is a Long Term Source of Contamination to
  Groundwater
• Limiting Factor for Site Cleanup
• Toxicity (i.e. carcinogens, mutagens, teratogens)
• Drinking Water Health Standards
• Traditional Methods are Ineffective for NAPL
  Cleanup
• i.e. Pump Treat

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Strategy to Deal with NAPL in GW
Use of Chemical Flushing Agents to Enhance NAPL
Removal
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Problem With Characterization(physical structure
of sediment/NAPL distribution)

• Technical Limitations difficult to understand
  mechanisms and processes at a fundamental scale
• Point samples and point measurements
• (Does not account for large volumes to be
  assessed)
• Difficult to sample a large domain
• For NAPL Contamination
• For Physical Sediment (Porous Media) Properties
• Difficult to quantify amount of NAPL in
  subsurface important for successful remediation
• Difficult to quantify sediment properties -
  important to predict contaminant transport
• Difficult to make accurate risk assessment

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Tools to Improve Characterization
Use of X-ray Microtomography and Chemical Tracer
Tests in the Lab and Field
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My Work Related to Contaminant Transport
Remediation

• Pore Scale

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My Work Related to Contaminant Transport
Remediation

• Lab-Intermediate Scale

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My Work Related to Contaminant Transport
Remediation

• Field Scale

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Pore Scale Research
Characterization of NAPL using Synchrotron
X-ray Microtomography

• quantify NAPL-phase distributions
• allows for more accurate assessment of NAPL
• dissolution rates (function of NAPL
  interfacial area)

Advanced Photon Source (APS) Argonne National
Laboratory
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Pore Scale Research
Slice 118 of 514 slices of the Column PCE in a
Saturated Carbonate-Karst Soil
3-D NAPL Distribution
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Pore Scale Research
Quantification Blob Size, Interfacial Area, and
Morphology
Cumulative Distribution of NAPL Blobs
fraction
Finer Than
Finer Than
Blob Volume (mm3)
Blob Volume (mm3)
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Pore Scale Research
Blob Volume (mm3)
Blob Surface Area (mm2)
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Laboratory Scale Research
Remediation of Immiscible-Liquid TCE
Using Multiple Enhanced-Solubilization Agents
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Lab Scale Research
Testing Different Chemical Flushing Agents on
NAPL Removal

• 4 Flushing Agents Tested
• 50 Ethanol
• 5 Methyl-?-Cyclodextrin (MCD)
• 5 Hydroxypropyl-?-Cyclodextrin (HPCD)
• 5 Dodecyl Sulfate Surfactant (SDS)

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Lab Scale Research
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Lab Scale Research

• Effect of Enhanced Solubilization Agents on TCE
  Removal
• homogeneous NAPL distribution, homogeneous media

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Lab Scale Research
homogeneous NAPL distribution, homogeneous media
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Laboratory Scale Research
Immiscible-liquid TCE Source Zone Length on
Dissolution Rates
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Lab Scale Research
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Lab Scale Research
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Lab Scale Research

• Water Flushing on TCE Removal for Varying Source
  Length
• Determine Dissolution Rates

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Lab Scale Research
Dissolution Rates Remain Similar Under Different
Source Zone Dimension
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Field Scale Research
Characterization of Subsurface Properties Using a
Diffusive Tracer Test
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Field Scale Research
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Field Scale Research
Diffusive Tracer Test to Determine Tortuosity and
Effective Radius of Influence (Sampled Domain)
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Field Scale Research

• Diffusive Tracer Dissipation Curves (replicates)
  
• quantify subsurface tortuosity and radius of
  diffusion

? 0.364?0.036
re 50 cm
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Field Scale Research
Partitioning Tracer Test to Characterize NAPL in
the Subsurface
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(GRFL Dover AFB, DE)
Field Scale Research
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Tracer Transport and Partitioning
Field Scale Research
tnp
tp
Tnp
Tp
non-partitioning tracer partitioning tracer
KNW is the NAPL water partition coefficient
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Field Scale Research

• Partitioning Tracer Test
• Determine NAPL Volume and Spatial Location

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Field Scale Research

• Partitioning Tracer Test
• Determine NAPL Volume and Saturation

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Field Scale Research
Remediation of Immiscible-Liquid PCE Using An
Enhanced-Solubilization Agent
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Field Scale Research
Enhanced-solubilization Agent

• Complexing Sugars
• Hydroxypropyl-?-Cyclodextrin (HPCD)
• Surfactants
• Cosolvents/Alcohols
• Humic Acids

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Complexing SugarHydroxypropyl-?-Cyclodextrin
(HPCD)
Field Scale Research
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Site Layout (GRFL Dover AFB, DE)
Field Scale Research
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Site Layout Dover AFB, DE
Field Scale Research
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Field Scale Research

• Cyclodextrin Flush vs. Water Flush
• Enhanced Removal vs. Traditional Pump Treat

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Results Mass Removal
Field Scale Research
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Results Removal Efficiency
Field Scale Research
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Thank You
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Pore Scale Research
Surface Area/Volume (mm-1)
Blob Volume (mm3)
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Lab Scale Research

• Testing Different Chemical Flushing Agents
• on NAPL Removal
• NAPL Trichloroethene (TCE)
• Different Porous Media
• Different NAPL Emplacement Techniques

• 4 Flushing Agents Tested
• 50 Ethanol
• 5 Methyl-?-Cyclodextrin (MCD)
• 5 Hydroxypropyl-?-Cyclodextrin (HPCD)
• 5 Dodecyl Sulfate Surfactant (SDS)

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Lab Scale Research

• Effect of Enhanced Solubilization Agents on TCE
  Removal
• heterogeneous NAPL distribution, homogeneous
  media

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Lab Scale Research
homogeneous NAPL distribution, homogeneous media
heterogeneous NAPL distribution, homogeneous
media