Influence of Algae on Soil Saturated Hydraulic Conductivity

121 Pages·2017·3.26 MB·English

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Masters Theses Graduate School
5-2017
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Molly Brianne Pattullo
University of Tennessee, Knoxville, [email protected]
Follow this and additional works at: https://trace.tennessee.edu/utk_gradthes
Part of the Biogeochemistry Commons, and the Soil Science Commons
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Pattullo, Molly Brianne, "Influence of Algae on Soil Saturated Hydraulic Conductivity: An in situ Treatment
Option for Reducing Infiltration Beneath Unlined Algae Cultivation Ponds. " Master's Thesis, University of
Tennessee, 2017.
https://trace.tennessee.edu/utk_gradthes/4770
This Thesis is brought to you for free and open access by the Graduate School at TRACE: Tennessee Research and
Creative Exchange. It has been accepted for inclusion in Masters Theses by an authorized administrator of TRACE:
Tennessee Research and Creative Exchange. For more information, please contact [email protected].
To the Graduate Council:
I am submitting herewith a thesis written by Molly Brianne Pattullo entitled "Influence of Algae
on Soil Saturated Hydraulic Conductivity: An in situ Treatment Option for Reducing Infiltration
Beneath Unlined Algae Cultivation Ponds." I have examined the final electronic copy of this
thesis for form and content and recommend that it be accepted in partial fulfillment of the
requirements for the degree of Master of Science, with a major in Geology.
Ed Perfect, Melanie A. Mayes, Major Professor
We have read this thesis and recommend its acceptance:
Larry D. McKay
Accepted for the Council:
Dixie L. Thompson
Vice Provost and Dean of the Graduate School
(Original signatures are on file with official student records.)
Influence of Algae on Soil Saturated Hydraulic Conductivity:
An in situ Treatment Option for Reducing Infiltration
Beneath Unlined Algae Cultivation Ponds

A Thesis Presented for the
Master of Science
Degree
The University of Tennessee, Knoxville

Molly Brianne Pattullo
May 2017
Copyright © 2017 by Molly Brianne Pattullo.
All rights reserved.

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Dedication

For my mother – an eternal fount of inspiration and encouragement

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Acknowledgements
As this chapter of my education comes to a close, I would like to reflect on the people
who encouraged me to begin and those who made finishing possible. I would especially like to
thank my mother who instilled in me a love of learning and fostered my interest in science.
Thanks for encouraging me to aspire to lofty goals, teaching me the value of hard work, and for
wise advice and unconditional support. I also thank my grandparents for their inspiration,
humour, and endless encouragement.
I thank my faculty advisor Dr. Edmund Perfect for accepting me into his research group.
His guidance and feedback has been invaluable over the past three years. Thanks to Dr. Melanie
Mayes for agreeing to co-advise me. I appreciate her always making time to provide feedback
and her encouragement and advice during setbacks. Her career and mentoring have been
inspirational to me. I also thank Dr. Larry McKay for the advice, feedback, and serving on my
committee. Thanks to Dr. Rebecca Efroymson for allowing me to work on this project and for
providing ideas, feedback, and GRA funding.
I am very grateful to everyone I worked with at Oak Ridge National Lab. Their help was
indispensable to this project. Many thanks to Jana Phillips for the endless smiles, collecting
samples, training me in the lab, and always making time to help me do or find whatever I need.
Thanks to Shane Franklin for helping in the data collection phase. I especially appreciate the
hours he spent washing the thousands of test tubes we used; without him, I would probably
still be standing at the lab sink. I also thank Dr. Terry Mathews and Dr. Shovon Mandal for their
input on this project and help with the algae. I acknowledge those who provided soils to test in
this project: Dr. Anthony Siccardi and Eric Myers from TX A&M AgriLife Research; Dr. Thomas
Dempster from Arizona State University’s AzCATI facility; Brian Condon with Gainesville
Renewable Energy Center; and Thomas Steffen, Ruth Spierling, and Dr. Tryg Lundquist from Cal
Poly San Luis Obispo.
I also thank my officemates and good friends Ariana Boyd, Emily Nield, and Ryan Quinn
for providing ideas, feedback, editing, coffee, laughter, and patience in helping me understand
statistics. Their friendships have benefitted my work tremendously and made this process a lot
of fun.
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Abstract
Commercial production of algal biofuels is currently limited by high capital costs,
including the cost of installation and maintenance of plastic pond liners, which mitigate
seepage of cultivation fluids and control the release of salts and nutrients into the subsurface
beneath outdoor algae cultivation ponds. However, studies of animal waste settling lagoons
show that underlying soils ranging from sands to clay loams can exhibit reduced hydraulic
conductivity within days to weeks after construction, reducing the need for plastic liners. The
mechanisms of the hydraulic conductivity reductions, or “soil sealing”, are physical
rearrangement of soil particles, buildup of fines, and the accumulation of microorganisms and
their metabolic products within pore spaces.
In this study, laboratory-scale soil column experiments investigated a new application
for old technology by using fluids that are low-cost and readily available in algae biofuel
production to reduce the saturated hydraulic conductivity (K ) of soils of varying textures by
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promoting physical and microbial pore clogging mechanisms. Three fluid treatments were
supplied to a fine sand soil 1) a nutrient solution used in commercial algae cultivation (NS), 2)
the nutrient solution with glycerol added (NSG) and 3) algae (Scenedesmus dimorphus) growing
in the nutrient solution (NSA). Relatively small reductions of K by NS (44-63%) indicate that the
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culture broth alone was insufficient to promote soil clogging. Larger reductions (77-94%) were
seen by addition of the carbon substrate glycerol to the nutrient solution, indicative of
enhanced bacterial growth. However, the K values produced by the NSG varied widely over
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time. The magnitudes of KS reductions by NSA were also large (84-95%) and remained stable.
The large, stable K reductions provided by algae, seen in the fine sand soil, were similar
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to those for a loamy sand (96-99%) and a loam soil (98%). The approximately two-order-of-
magnitude K reductions imply that, like organic fines in animal waste holding ponds, algae can
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also significantly contribute to reductions in K of soils. This new technology appears to be
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successful in reducing the K of native soils and suggests the technology could be applied as an
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alternative to plastic liners.
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Table of Content
Chapter 1: Introduction and Literature Review .............................................................................. 1
Meeting the World’s Energy Needs ............................................................................................ 1
First- and Second-Generation Biofuels .................................................................................... 1
Microalgae: The Third Generation Biofuel .............................................................................. 2
Microalgae Production ................................................................................................................ 3
Strain Selection ........................................................................................................................ 4
Downstream Processes ........................................................................................................... 5
Commercial Products .............................................................................................................. 6
Cultivation ................................................................................................................................ 7
Assessments of Current Production Practices .......................................................................... 10
Burdens Associated with Cultivation Pond Liners ................................................................. 12
Alternatives to Synthetic Pond Liners ................................................................................... 14
In-Situ Solutions ..................................................................................................................... 15
Column Experiments on Saturated Hydraulic Conductivity Reductions ................................... 20
Mechanisms of Porous Media Clogging ................................................................................ 22
Can Algae Cultivation Ponds Be Built Without Engineered Liners? .......................................... 30
Rationale ................................................................................................................................ 30
Goal ........................................................................................................................................ 33
Hypothesis ............................................................................................................................. 33
Objective ................................................................................................................................ 33
Approach ............................................................................................................................... 33
Chapter 2: Materials and Methods ............................................................................................... 35
Soils ........................................................................................................................................... 38
Soil Characterization ................................................................................................................. 38
Apparatus .................................................................................................................................. 40
Solutions .................................................................................................................................... 41
Experimental Procedure ............................................................................................................ 43
Chapter 3: Results and Discussion ................................................................................................ 46
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Phase I: Preliminary Experiment ............................................................................................... 46
Phase II: Scoping Experiments .................................................................................................. 50
Tennessee Loam Soil with Glycerol Amended Nutrient Solution ......................................... 51
Comparison of Solutions on K of Corpus Christi Sand.......................................................... 54
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Phase III: Hydraulic Conductivity Reductions by Algae ............................................................. 65
California Loamy Sand ........................................................................................................... 66
Tennessee Loam Soil ............................................................................................................. 68
Focused Ion Beam Scanning Electron Microscopy .................................................................... 70
Statistical Analyses .................................................................................................................... 78
Influence of Factors Affecting K and Bulk Density ............................................................... 78
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Effect of Treatments on K and Bulk Density......................................................................... 83
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Chapter 4: Conclusions and Future Work ..................................................................................... 84
References .................................................................................................................................... 86
Appendices .................................................................................................................................. 101
Vita .............................................................................................................................................. 109

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List of Tables
Table 1: Overview of the Different Phases of the Study .......................................................37
Table 2: Soil Characterizations ...............................................................................................39
Table 3: Nutrient Solution Composition ................................................................................42
Table 4: Preliminary Experiment Results ...............................................................................48
Table 5: Results of Phase II Glycerol Amended Nutrient Solution on Freel’s Bend Loam Soil
................................................................................................................................................53
Table 6: Results of Phase II Scoping Experiments on Texas Fine Sand Columns ...................62
Table 7: Results of Phase III Experiments on California Loamy Sand and Tennessee Loam Soil
Columns .................................................................................................................................68
Table 8: Changes to K and Bulk Density ................................................................................79
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Table 9: ANOVA with Replication Statistics ...........................................................................79
Table 10: ANOVA without Replication Statistics ...................................................................80
Table 11: Effect of Treatment on Changes in K and Bulk Density ........................................83
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Table B.1: Cell and Optical Densities for Scenedesmus dimorphus Stock Culture Dilutions .104

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