Enhancing the Performance of Anaerobic Bioreactors for the Biological Degradation of Volatiles

232 Pages·2017·11.29 MB·English

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LSU Doctoral Dissertations Graduate School
8-29-2017
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Leslie Michele Pipkin
Louisiana State University and Agricultural and Mechanical College
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Pipkin, Leslie Michele, "Enhancing the Performance of Anaerobic Bioreactors for the Biological
Degradation of Volatiles Organic Compounds in Groundwater Using Alternate Electron Acceptors" (2017).
LSU Doctoral Dissertations. 4106.
https://digitalcommons.lsu.edu/gradschool_dissertations/4106
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ENHANCING THE PERFORMANCE OF ANAEROBIC BIOREACTORS FOR
THE BIOLOGICAL DEGRADATION OF VOLATILE ORGANIC
COMPOUNDS IN GROUNDWATER USING ALTERNATE
ELECTRON ACCEPTORS

A Dissertation

Submitted to the Graduate Faculty of the
Louisiana State University and
Agricultural and Mechanical College
in partial fulfillment of the
requirements for the degree of
Doctor of Philosophy

in

The Department of Civil and Environmental Engineering

by
Leslie Michele Pipkin
B.S., Florida State University, 2010
M.S., Florida State University, 2012
December 2017
ACKNOWLEDGEMENTS
I would like to recognize those who have encouraged, directed, and supported me during
my studies at Louisiana State University leading to my doctoral degree and this dissertation. I
am forever grateful for my major advisor Dr. John Pardue for providing me the opportunity to
work on this research project and for his profound ideas, exceptional direction, beneficial
recommendations, and inspiration throughout my graduate academic career at LSU. I would also
like to thank the members of my advisory committee, Dr. William Moe, Dr. Clinton Willson, and
Dr. John White for providing instrumental feedback, guidance and encouragement during my
dissertation. I’m grateful for the funding provided for the study by the Louisiana Board of
Regents Fellowship and The Governor’s Biotechnology Initiative.
I would also like to thank Mr. Frederick Symmes of Weston Solutions Inc. for his
assistance in granting me access and allowing sampling trips to take place at the Re-Solve, Inc.
Superfund Site in Massachusetts.
Many thanks to my fellow colleagues and associates at Louisiana State University who
have provided assistance and support over the years: Dr. Vijai Elango, Dr. Christopher Akudo,
Trent Key, Davis Lofton, Michael Cheatham, Yasmin Mohammad, Autumn Westrick, David
Curtis, Mathew Rodrigue, Matt Decell, Barry Breaux, and Jacob Vigh.
Lastly I would like to thank my family and close friends for their continued love and
support during this endeavor. Specifically I would like to recognize my parents, Nancy and
David, my brother Andrew, my cousin Sabrina Rodriguez, and my love Nicholas Smith, as well
as my close friends Shannon Haltom, Brandon and Lanie White, and Payton Dupree for their
constant encouragement.

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TABLE OF CONTENTS
ACKNOWLEDGEMENTS ............................................................................................................ ii

ABSTRACT .....................................................................................................................................v

CHAPTER 1: INTRODUCTION ....................................................................................................1
1.1 General Introduction ......................................................................................................1
1.2 Purpose of Study ............................................................................................................2
1.3 Research Objectives .......................................................................................................3
1.4 Organization of Dissertation ..........................................................................................4

CHAPTER 2: LITERATURE REVIEW .........................................................................................6
2.1 A Brief History Into the Volatile Organic Compounds of Interest ................................6
2.2 Biodegradation of BTEX ...............................................................................................9
2.3 Biodegradation of Chlorinated Solvents ......................................................................15
2.4 Development of ABRs for Treatment of VOCs ..........................................................19
25 Enhancement of ABR Treatment Design and Approach .............................................24

CHAPTER 3: A SUSTAINABLE BIOREMEDIATION APPROACH FOR
BTEX- CONTAMINATED GROUNDWATER UNDER
METHANOGENIC AND SULFATE-REDUCING CONDITIONS ....................26
3.1 Introduction ..................................................................................................................26
3.2 Materials and Methods .................................................................................................28
3.3 Results and Discussion ................................................................................................34
3.4 Design Implications .....................................................................................................63

CHAPTER 4: COMPLETE DEGRADATION OF CHLORINATED
ETHANES IN SEQUENTIAL BIOREACTORS OPERATED
UNDER VARYING REDOX CONDITIONS .......................................................64
4.1 Introduction ..................................................................................................................64
4.2 Materials and Methods .................................................................................................66
4.3 Results and Discussion ................................................................................................75
4.4 Design Implications ...................................................................................................105

CHAPTER 5: ANALYSIS OF SYSTEM PERFORMANCE OF FULL-SCALE
ANAEROBIC BIOREACTOR TREATMENT BEDS ........................................106
5.1 Introduction ................................................................................................................106
5.2 Materials and Methods ...............................................................................................111
5.3 Results and Discussion ..............................................................................................121
4.4 Design Implications ...................................................................................................159

CHAPTER 6: CONCLUSIONS AND RECOMMENDATIONS ...............................................160

REFERENCES ............................................................................................................................165

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APPENDIX ..................................................................................................................................190

VITA ............................................................................................................................................225

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ABSTRACT
Engineered anaerobic bioreactors (ABR) constructed from mixed media and sand can
biodegrade high concentrations of volatile organic compounds (VOCs). Sustainable treatment of
benzene, toluene, ethylbenzene, and xylenes (BTEX), chlorinated ethenes and ethanes were used
to investigate the use of engineered ABRs, while also analyzing the system performance of a
full-scale ABR system. Experimentations conducted on environmental and biological factors that
affect ABR system performance was conducted through serum bottles, columns, and reactor
studies.
Column and reactor ABR systems were designed to treat VOCs via biodegradation in
groundwater with varying terminal electron acceptors (TEAs). Laboratory-scale column ABRs
were constructed to treat BTEX compounds while simultaneously adjusting the TEA processes
in the bed between methanogenic and sulfate-reducing conditions. Analysis of the groundwater
showed that amending the contaminated water with sulfate lead to higher percentages of
degradation of BTEX. Experimentations showed that sizing of a full-scale ABR treatment bed
would be controlled by benzene due to the lower removal efficiency and lower required
discharge limits.
A two-phase pilot-scale ABR system was operated through the use of sequential
anaerobic/aerobic ABRs to reductively dechlorinate 1,1,1-trichloroethane (TCA) to chloroethane
(CA), followed by aerobic oxidation of CA. Two duplicate reactors operated in parallel in an up-
flow mode were prepared for aerobic treatment studies of CA. Pure oxygen was supplied
through a porous silastic tube under pressure with a pure oxygen gas cylinder. Investigations
concluded that complete mineralization of chloroethane was observed in the effluents from
the aerobic zone of the ABR system. During both studies, TEA changes were confirmed by
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using a 16S rRNA assessment of microbial populations within the ABR beds, which indicated a
shift in bacteria and/or archaea to a more effectual degrading community structure.
Two full-scale ABR beds were analyzed for system performance through two sampling
trips to the ReSolve, Inc. Superfund Site. Groundwater samples were collected along the length
of both ABRs for analysis of chlorinated ethenes and ethanes, while suspended and attached
bacteria samples were collected via groundwater and core sampling. Data collected from the
Site determined that the ABRs displayed consistent losses of chlorinated ethenes and ethanes,
with the exception of minor CA accumulation in the ABRs in 2014, with CA degradation
occurring in 2015, showing that the system performance improved over the course of the year.

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CHAPTER 1. INTRODUCTION
1.1 General Introduction
Clean groundwater is crucial to meet the demands of public, agricultural, and industrial
entities and is among the most important natural resources. Groundwater contamination of
Volatile Organic Compounds is considered one of the many key sources for deterioration of
water quality in the United States (El-Naas et al., 2014). Until the 1970s, companies both
deliberately (through agricultural applications or improper disposal) or unknowingly polluted
adjacent groundwater aquifers due to lack of knowledge and non-existent environmental laws at
the time (Boudreau, 2013). After events of the discovery of toxic waste sites like the Love Canal
and Times Beach, public awareness, along with the creation of environmental bills such as the
Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA or
Superfund) brought to light appropriate chemical and waste disposal practices to the United
States. This statute gave the EPA the authority to clean up uncontrolled hazardous waste sites
and spills to protect human health and the environment.
Due to the increasing number of contaminants found in the environment today (Zogorski
et al., 2006; Yu et al., 2015), there is a large demand for practical and efficient remediation
technologies that are cost-effective and sustainable, such as bioremediation (Boopathy, 2000;
Mazzeo et al., 2010; Naidu, 2013). Traditional treatment technologies, such as pump-and-treat,
air sparging, and soil vapor extractions are the dominant choices for remediation. The use of
chemical and physical treatment of groundwater can be both applied ex situ and in situ. These
traditional treatment methods have proved limitations and high costs of continuous operations.
In situ bioremediation (also known as natural attenuation) may use the natural bacteria in the soil
and groundwater to transform the organic compounds to acceptable limits or become less mobile
1
compounds in the environment, which include petroleum hydrocarbons and chlorinated solvents
(USEPA, 1990). Bioremediation is a cost-effective remediation technology and is primarily
related to the costs of site evaluation and monitoring (Khan et al., 2004). The research presented
in this dissertation is based on the use of bioremediation as a viable technology to destroy a
variety of contaminants in diverse anaerobic bioreactor systems.
1.2 Purpose of Study
The research outlined in this dissertation is geared towards the understanding of alternate
electron acceptors in anaerobic bioremediation (ABRs) systems while understanding the
mechanisms and the functional roles of bacteria and geochemistry through diversifying TEAs.
Specifically, a variety of experiments are conducted using two different ABR systems, one
anaerobically treating BTEX, while the other is sequentially anaerobically and aerobically
treating 1,1-dichloroethane (1,1-DCA) and chloroethane (CA). These represent investigations of
two significant challenges for bioreactor systems: degrading VOC contaminants that are difficult
to degrade like benzene under anaerobic conditions and providing oxygen to degrade
contaminants where further transformation ceases and is not typically observed in the absence of
oxygen such as chloroethane. These experiments will be supplemented by the field
measurements of microbial populations in the first field scale application of these bioreactors at
the ReSolve, Inc. Superfund Site (Site) in southern Massachusetts. The general challenge that
these studies address is how to alter the geochemical conditions present in these systems to
accomplish efficient biodegradation in the smallest volumes possible. The experimental plan
consists of testing the biodegradation of varying TEA, from methanogenic conditions, to sulfate
reducing conditions, to amending with oxygen to treat CA. Both of these bioreactor systems will
identify the characterizations of varying microbial communities throughout the experiments
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using DNA extractions, followed by sequencing for the 16S rRNA gene using next generation
sequencing (NGS) techniques.
1.3 Research Objectives
The principal objectives and tasks of this dissertation research is to better understand how
alternate electron acceptors can manipulate the conditions in anaerobic bioreactors to create
biogeochemical conditions for a range of biodegradation reactions. The specific objectives and
tasks of the research are as follows:
(1) Assessment of enhanced microbial treatment of benzene, toluene, ethylbenzene, and total
xylenes in ABRs systems and the evaluation of varying terminal electron acceptor processes.
These activities will include evaluation and identification of microbial genomes and their
transformations between TEA processes for bioremediation of BTEX;
A) Task 1: Assessment of enhanced microbial treatment of BTEX and the evaluation of
TEA processes
B) Task 2: Genomic DNA analysis of laboratory scale ABRs for bioremediation of
BTEX
(2) The examination of pure oxygen input into ABRs for chloroethane aerobic biodegradation;
including the evaluation of chloroethane biodegradation in bioreactor treatment beds and the
identification of microorganisms associated with biodegradation, where oxygen is the only viable
electron acceptor;
C) Task 3: Examination of oxygen input into bioremediation beds for chloroethane
aerobic biodegradation
D) Task 4: Evaluation of chloroethane biodegradation and genomic DNA analysis
associated with biodegradation
3