CONTAMINANT FATE AND TRANSPORT ANALYSIS IN SOIL-PLANT SYSTEMS A Thesis ...

338 Pages·2011·2.43 MB·English

CONTAMINANT FATE AND TRANSPORT ANALYSIS
IN SOIL-PLANT SYSTEMS

A Thesis
Presented to
The Academic Faculty

By

Recep Kaya Goktas

In Partial Fulfillment
Of the Requirements for the Degree
Doctor of Philosophy in Environmental Engineering

Georgia Institute of Technology

May 2011
CONTAMINANT FATE AND TRANSPORT ANALYSIS
IN SOIL-PLANT SYSTEMS

Approved by:

Dr. Mustafa M. Aral, Advisor Dr. Marc Stieglitz
School of Civil and Environmental School of Civil and Environmental
Engineering Engineering
Georgia Institute of Technology Georgia Institute of Technology

Dr. Jiabao Guan Dr. Turgay Uzer
School of Civil and Environmental School of Physics
Engineering Georgia Institute of Technology
Georgia Institute of Technology

Dr. Wonyong Jang Date Approved: December 17, 2010
School of Civil and Environmental
Engineering
Georgia Institute of Technology

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Aileme

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ACKNOWLEDGEMENTS

I would like to express my deepest gratitude to my advisor Dr. Mustafa M. Aral for his
guidance, patience, understanding and support all throughout the study.

I would like to send my sincere appreciation to Dr. Jiabao Guan and Dr. Wonyong Jang,
who have been extremely helpful throughout the study as the members of the MESL
group, as well as the members of the Ph.D. committee.

I would also like to thank to the Ph.D. committee members Dr. Marc Stieglitz and Dr.
Turgay Uzer for their very valuable comments and enlightening suggestions.

I gratefully acknowledge the financial support from the Turkish Higher Education
Council and Kocaeli University.

I would like to send my special thanks to the past and present MESL members Dr. Elcin
Kentel, Dr. Jinjun Wang, Dr. Sinem Gokgoz Kilic, Dr. Kijin Nam, Dr. Scott Rogers, Mr.
Ilker T. Telci, Ms. Radhika Dhingra, Mr. Andi Zhang, Mr. Biao Chang, and Mr. Will
Morgan for their professional support and friendship.

I would also like to send my regards and love to my dear friends Ulas Tezel, Burcak
Kaynak, Ayten Memmedova Telci, Deniz Telci, Akash Dixit, Kaya Demir, Bahar
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Ulukan, Zohre Kurt, Tjames Scott, and Ronda Patino, who have made my life in the U.S.
much more meaningful than it could otherwise have been.

The words fall short to express my gratitude to my family – my mother Cemile, my father
Kadir, and my sister Demet – who have always been there with their endless love and
support.

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TABLE OF CONTENTS

ACKNOWLEDGEMENTS ............................................................................................... iv

LIST OF TABLES ............................................................................................................. ix

LIST OF FIGURES ............................................................................................................ x

SUMMARY .................................................................................................................... xvii

CHAPTER 1: INTRODUCTION ...................................................................................... 1
1.1 Environmental Modeling and Plants ................................................................... 1
1.2 Environmental Modeling Approach Adopted in this Study ............................... 2
1.3 Scope of the Study .............................................................................................. 5
1.4 Thesis Organization ............................................................................................ 6

CHAPTER 2: BACKGROUND AND LITERATURE REVIEW .................................... 8
2.1 Multimedia Compartmental Models ................................................................... 8
2.2 Single Media Continuous Models ..................................................................... 13
2.3 Plant Pathway Modeling ................................................................................... 15
2.4 Plant Growth Modeling..................................................................................... 18
2.5 Hydrological Processes in Soil-Plant Systems ................................................. 22
2.5.1 Hydrological Process Models ................................................................... 22
2.5.2 Coupling the Hydrological Process Models ............................................. 29
2.6 Contaminant Fate and Transport Processes in Soil-Plant Systems ................... 34
2.6.1 Contaminant Fate and Transport Models .................................................. 34
2.6.2 Coupling the Contaminant Fate and Transport Models ............................ 36

CHAPTER 3: PLANT PATHWAY ................................................................................ 38
3.1 Plant Pathway Model ........................................................................................ 38
3.1.1 Mass Transfer Processes ........................................................................... 38
3.1.1.1 Atmospheric Deposition ....................................................................... 39
3.1.1.2 Diffusive Transfers between the Plant and the Atmosphere ................. 41
3.1.1.3 Transformation within the Plant ........................................................... 43
3.1.1.4 Washoff ................................................................................................. 43
3.1.1.5 Litterfall and Root Decay...................................................................... 44
3.1.1.6 Root Uptake .......................................................................................... 45
3.1.2 Mass Balance Equation ............................................................................. 46
3.2 Plant Life-Cycle Model..................................................................................... 47
3.2.1 The Leaf Area Index Simulation Model ................................................... 48
3.2.2 The Plant Biomass Model ......................................................................... 49
3.2.3 The Root Model ........................................................................................ 51

CHAPTER 4: FLOW AND TRANSPORT MODELS ................................................... 54
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4.1 Unsaturated Zone Soil-Water Flow Model ....................................................... 54
4.1.1 Model Development.................................................................................. 54
4.1.2 Model Testing ........................................................................................... 59
4.2 Vadose Zone Contaminant Transport Model .................................................... 66
4.2.1 Model Development.................................................................................. 66
4.2.2 Model Testing ........................................................................................... 71
4.3 Overland Flow Model ....................................................................................... 73
4.3.1 Model Development.................................................................................. 73
4.3.2 Model Testing ........................................................................................... 79
4.4 Overland Transport Model ................................................................................ 86
4.4.1 Model Development.................................................................................. 86
4.4.2 Model Testing ........................................................................................... 90

CHAPTER 5: INTEGRATED DYNAMIC MODELING OF THE SOIL-PLANT
SYSTEM ........................................................................................................................... 97
5.1 Introduction ....................................................................................................... 97
5.2 Integrated Model Development ........................................................................ 98
5.2.1 Coupling the Unsaturated Zone Water Flow and the Plant Life-Cycle
Models ................................................................................................................... 99
5.2.1.1 Ground Surface Boundary .................................................................... 99
5.2.1.2 Root Water Uptake ............................................................................. 105
5.2.2 Coupling the Vadose Zone Contaminant Transport and the Plant Pathway
Models ................................................................................................................. 112
5.3 Model Application .......................................................................................... 114
5.3.1 Modeling Domain and the Model Parameters ........................................ 115
5.3.2 Description of Simulations ..................................................................... 121
5.3.3 Results and Discussion ........................................................................... 123
5.3.3.1 Plant Life-Cycle .................................................................................. 123
5.3.3.2 Soil-water Distribution........................................................................ 127
5.3.3.3 Contaminant Distribution in Soil ........................................................ 131
5.3.3.4 Plant Pathway...................................................................................... 135
5.3.3.5 Mass Balance Analysis ....................................................................... 137
5.3.3.6 Sensitivity Analysis ............................................................................ 142
5.4 Conclusion ...................................................................................................... 146

CHAPTER 6: INTEGRATED MODELING OF WATER FLOW IN A TERRESTRIAL
SYSTEM ......................................................................................................................... 149
6.1 Introduction ..................................................................................................... 149
6.2 Integrated Model Development ...................................................................... 150
6.2.1 Coupling Overland Flow and Unsaturated Zone Soil-Water Flow Models .
................................................................................................................. 151
6.2.2 Incorporating the Subsurface Lateral Fluxes .......................................... 160
6.2.3 Effect of Plants on Overland Flow.......................................................... 161
6.3 Model Application .......................................................................................... 165
6.3.1 Modeling Domain and the Model Parameters ........................................ 165
6.3.2 Description of the Simulations................................................................ 171
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6.3.3 Results and Discussion ........................................................................... 172
6.3.3.1 Daily Simulations................................................................................ 173
6.3.3.2 Seasonal Simulations .......................................................................... 184
6.4 Conclusion ...................................................................................................... 195

CHAPTER 7: INTEGRATED MODELING OF CONTAMINANT FATE AND
TRANSPORT IN A TERRESTRIAL SYSTEM ............................................................ 196
7.1 Introduction ..................................................................................................... 196
7.2 Integrated Model Development ...................................................................... 197
7.2.1 Coupling Overland Transport and Vadose Zone Transport Models ....... 198
7.2.2 Incorporating the Subsurface Lateral Fluxes .......................................... 210
7.3 Model Application .......................................................................................... 214
7.3.1 Modeling Domain and the Model Parameters ........................................ 214
7.3.2 Description of the Simulations................................................................ 215
7.3.3 Results and Discussion ........................................................................... 216
7.3.3.1 Daily Simulations................................................................................ 216
7.3.3.2 Seasonal Simulations .......................................................................... 227
7.4 Conclusion ...................................................................................................... 254

CHAPTER 8: CONCLUSIONS AND RECOMMENDATIONS ................................. 255
8.1 Conclusions ..................................................................................................... 255
8.2 Recommendations ........................................................................................... 257

APPENDIX A: SPATIAL DISCRETIZATION OF THE UNSATURATED FLOW
MODEL .......................................................................................................................... 260

APPENDIX B: SPATIAL DISCRETIZATION OF THE VADOSE ZONE
TRANSPORT MODEL .................................................................................................. 269

APPENDIX C: SPATIAL DISCRETIZATION OF THE OVERLAND FLOW MODEL
......................................................................................................................................... 281

APPENDIX D: SPATIAL DISCRETIZATION OF THE OVERLAND TRANSPORT
MODEL .......................................................................................................................... 291

APPENDIX E: TIME INTEGRATION ........................................................................ 296

APPENDIX F: TIME INTEGRATION WITH PICARD ITERATION ....................... 299

REFERENCES ............................................................................................................... 302

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LIST OF TABLES

Table 3.1: Mass transfer processes considered in the resultant plant pathway model. ..... 46

Table 4.1: Test parameters used in the soil transport model comparison with the
analytical solution. ............................................................................................................ 72
Table 4.2: Test parameters used in overland flow model comparison with 1D analytical
solution. ............................................................................................................................. 80
Table 4.3: Test parameters used in the comparison of overland flow model performance
with other numerical models for a 2D tilted V-catchment problem. ................................ 83
Table 4.4: Test parameters used in the comparison of the overland transport model with
the analytical solution. ...................................................................................................... 90

Table 5.1: Soil types and their characteristics used in the applications (Wohling and
Mailhol 2007).................................................................................................................. 115
Table 5.2: Weather data used in the simulations. ........................................................... 116
Table 5.3: Crop parameters (corn). (Mailhol et al. 1997; Wohling and Mailhol 2007) . 118
Table 5.4: Multimedia contaminant fate and transport model parameters. .................... 120
Table 5.5: Tabulated summary of the simulation set. ..................................................... 122

Table 6.1: Overland domain model parameters. ............................................................. 165
Table 6.2: The soil hydraulic parameters for a silt loam type soil (Vogel et al. 2001). . 167
Table 6.3: Crop parameters used in the simulations. ...................................................... 169
Table 6.4: Weather data used in the simulations. ........................................................... 170
Table 6.5: The comparison of the two types of irrigation methods applied. .................. 171
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LIST OF FIGURES

Figure 3.1: Plant pathway mass transfer processes considered in this study. ................... 39

Figure 4.1: Spatial discretization of the soil column. (j: cell numberD; DDDz: thickness of cell
j
j; q : water flux from cell j-1 to cell j)........................................................................... 56
j-1/2
Figure 4.2: The modeling domain and the initial (I.C) and boundary (B.C.) conditions for
the example problem of Lehman and Ackerer (1998). ..................................................... 59
Figure 4.3: Comparison of the results obtained by this study and the results of Lehman
and Ackerer (Lehmann and Ackerer 1998). ..................................................................... 61
Figure 4.4: Steady-state soil-water pressure head profiles in layered soil (loam over sand)
with a constant infiltration rate of 0.5 cm/day. (Comparison with the test in Vanderborght
et al. (2005)) ...................................................................................................................... 63
Figure 4.5: Steady-state soil-water pressure head profiles in layered soil (sand over loam)
with a constant infiltration rate of 0.5 cm/day. (Comparison with the test in Vanderborght
et al. (2005)) ...................................................................................................................... 64
Figure 4.6: Steady-state soil-water pressure head profiles in layered soil (clay over sand)
with a constant infiltration rate of 0.5 cm/day. (Comparison with the test in Vanderborght
et al. (2005)) ...................................................................................................................... 64
Figure 4.7: Steady-state soil-water pressure head profiles with a constant evaporation rate
of 0.5 cm/day. (Comparison with the test in Vanderborght et al. (2005)) ........................ 65
Figure 4.8: Soil transport model comparison with the analytical solution. ...................... 72
Figure 4.9: The overland flow modeling domain, cells and the grids. ............................. 78
Figure 4.10: Overland flow model comparison with 1D analytical solution. ................... 81
Figure 4.11: The profile of the 2D tilted V-catchment used in the overland flow model
testing. ............................................................................................................................... 82
Figure 4.12: Overland flow model results for the 2D V-catchment problem compared
with the other numerical models. (Case a: zero depth-gradient boundary condition at the
outlet) ................................................................................................................................ 84
Figure 4.13: Overland flow model results for the 2D V-catchment problem compared
with the other numerical models. (Case b: critical depth boundary condition at the outlet)
........................................................................................................................................... 85
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