Conceptual Design of an In-Situ Sequential Anaerobic/Aerobic
Bioremediation Scheme for Chlorinated Solvents in the
Landfill-1 Plume at the Massachusetts Military Reservation
by
Farnaz Saboori Haghseta
B.S. Chemical Engineering
Massachusetts Institute of Technology, 1996
Submitted to the Department of Civil and Environmental Engineering in Partial
Fulfillment of the Requirements for the Degree of
MASTER OF ENGINEERING
IN CIVIL AND ENVIRONMENTAL ENGINEERING
at the
MASSACHUSETTS INSTITUTE OF TECHNOLOGY
JUNE 1997
copyright
0 1997 Farnaz Saboori Haghseta.
All rights reserved.
The author hereby grants MIT permission to reproduce and to distribute publicly paper and electronic copies of this
thesis document in whole and in part.
-Farnaz Sabuoori Haghseta
Department of Civil and Environmental Engineering
May 9, 1997
Signature of Author
0
Certified by
r
I
v
I
Fernando Miralles-Wilhelm
Lecturer, Department o Civil and Environmental Engineering
Accepted by
- -~--~
V
V Joseph SSussman
Chairman, Departmental Committee on Graduate Studies
OF 'C•H-••'LY
JUN 2 41997
Eng.
Conceptual Design of an In-Situ Sequential Anaerobic/Aerobic
Bioremediation Scheme for Chlorinated Solvents in the Landfill-1 Plume at
the Massachusetts Military Reservation
by
Farnaz Saboori Haghseta
Submitted to the Department of Civil and Environmental Engineering on May 9, 1997 inPartial Fulfillment of the
Requirements for the Degree of Master of Engineering inCivil and Environmental Engineering
ABSTRACT
Chlorinated compounds represent the most prevalent organic groundwater contaminants
in the country. Until recently, bioremediation had not been considered a viable option for the
treatment of chlorinated solvents. There is now sufficient theoretical and experimental
information to suggest that in-situ bioremediation can be utilized to effectively degrade
chlorinated compounds.
A conceptual design is proposed for the in-situ bioremediation of tetrachloroethylene
(PCE) and trichloroethylene (TCE). These contaminants have been detected in LF-1, a plume
emanating from the Main Base Landfill at the Massachusetts Military Reservation in Cape Cod,
Massachusetts. The conceptual design relies on the establishment of sequential anaerobic and
aerobic biozones to reduce the local maximum PCE and TCE concentrations. These biozones are
created by the injection of essential components of bioremediation, which include nutrients,
growth substrates, and oxygen. The delivery of these agents to the areas of highest measured
PCE and TCE concentration is necessary for the successful biodegradation of these contaminants
in the LF-1 plume. Design parameters include the placement of injection wells to establish the
aerobic and anaerobic biozones, the radii of influence of the wells, selected substrates and
nutrients, and the concentrations and flow rates for the injected nutrients, oxygen, and substrates.
In order to induce the biodegradation processes, the design requires the following to be
injected at key locations in the plume: ammonium and phosphate as nutrients for the
microorganisms, methane substrate for the aerobic microorganisms, methanol substrate for the
anaerobic microorganisms, and oxygen for the stimulation of microorganisms in the aerobic
biozones. The estimated total time for bioremediation of TCE and PCE to 5 pg/L (the Maximum
Contaminant Level for TCE and PCE) ranges from five to fourteen years, depending upon the
extent of contamination and the background conditions at the particular location in the plume.
The bioremediation of chlorinated solvents is a promising treatment technology.
However, the lack of full-scale implementation to date leaves many questions to be answered,
particularly regarding the cost-effectiveness of the process. This conceptual design serves as a
basis for the development of pilot tests which can more accurately assess the effectiveness and
feasibility of this technology.
Thesis Supervisor: Fernando Miralles-Wilhelm
Title: Lecturer of Civil and Environmental Engineering
ACKNOWLEDGEMENTS
My deepest and warmest gratitude goes to my family and friends for their love
and support, especially during the past five years at MIT. I would like to thank Professor
Fernando Miralles- Wilhelm, whose kindness, direction, and valuable input was
instrumental in the completion of my thesis. I would like to thank Professor David Marks
and Shawn Morrisey for their constant support and encouragement, and for their
invaluable advice and guidance during the hectic job search process. I am also grateful to
my fellow LF-1 team members, Mia Lindsey, Roberto Le6n, Becky Kostek, and
Mandeera Wagle, who made the experience of writing a thesis as enjoyable as it could
possibly be.
TABLE OF CONTENTS
1. INTRODUCTION ...............................................................................................................................
7
1.1 PROBLEM STATEMENT ...........................................................................................................................
1.2 OBJECTIVE...................................................................................................7
1.3 SCOPE OF THESIS..............................................................................................................................8
9
2. SITE DESCRIPTION .........................................................................................................................
2.1
2.2
2.3
2.4
2.5
LOCATION AND HISTORY..................................................................................................................9
GEOLOGY .
.................................................
HYDROGEOLOGY..................................................................................................................................
ENVIRmONMENTAL POLLUTION AT MMR ..................................................
.......................
CHARACTERISTICS OF THE MAIN BASE LANDFILL.............................................
10
11
12
12
2.5.1 Landfilled Materials..................................................................................................................... 14
2.5.2 CurrentStatus of the Landfill....................................................................................................... 15
2.5.3 Contaminant Plume Resultingfrom the Landfill........................................... ............................ 15
2.5.3.1 Current Status of LF-I
17
......................................................................................................................................
18
3. BIOREMEDIATION ...........................................................................................................................
3.1 DEFINITION .................................................................................................................................... 18
18
3.2 MICROORGANISMS ....................................................................................................................
19
3.3 ENVIRONsMENTAL REQUIREMENTS .................................................................................................
.................................. 20
3.3.1 Nutrients...............................................................................................
3.3.2 Electron Acceptor ................................................................................................................... 21
..................................... 22
3.3.3 Substrate............................................................................................
3.3.4 Other Environmental Conditions............................................................................................24
3.3.4.1 Tem perature............................................................................................................................................24
.................................. . ........25
3.3.4.2 pH .......................................................................................................
3.3.4.3 Concentration Range of Contaminant .............................................................................................. 25
26
3.4 IN- SITU BIOREMEDIATION.............................................................................................................
3.4.1 Advantages over Remedial Alternatives................................................................................. 26
...... 28
4. CHARACTERIZATION OF THE LF-1 PLUME ...........................
4.1
4.2
4.3
4.4
4.5
PLUME CHARACTERIZATION .......................................................................................................... 28
SPATIAL DISTRIBUTION OF CONTAMINATION ................................................................................. 28
SPATIAL DISTRIBUTION OF NUTRIENTS .......................................................................................... 32
SPATIAL DISTRIBUTION OF OXYGEN .............................................................................................. 34
SPATIAL DISTRIBUTION OF SUBSTRATES........................................................................................36
4.6 SPATIAL DISTRIBUTION OF MICROORGANISMS............................................................................... 36
4.7 SPATIAL DISTRIBUTION OF TEMPERATURE AND PH...................................
.......
................ 36
5. SEQUENTIAL ANAEROBIC/AEROBIC DEGRADATION OF CHLORINATED SOLVENTS .37
5.1
5.2
5.3
5.4
BIODEGRADATION OF ORGANIC COMPOUNDS ................................................................ 37
40
TCE: AEROBIC COMETABOLIC DEGRADATION .......................................................
PCE: ANAEROBIC COMETABOLIC DEGRADATION.............................................................................44
47
COMBINATION OF ANAEROBIC AND AEROBIC PROCESSES.............................. ..............
6. DEVELOPMENT OF CONCEPTUAL DESIGN .....................................................
6.1
6.2
6.3
6.4
6.5
BASIS FOR CONCEPTUAL DESIGN ...................................................................................................
SUBSTRA-TE REQUIREMENT ....................................................................................................
OXYGEN REQUIREMENT .....................................................................................................................
BACTERIA
............................................................................................
REQUIREMENTS...........................
...............................................................................
NUTRIENT
4
48
48
48
49
50
51
6.6 ANALYTICAL MODELS .........................................................................................................................
51
6.6.1 Injection Wells..............................................................................................................................51
............................................. 55
6.6.2 Biodegradation..........................................................................
.................................. 57
7. CO N CEPTU A L D ESIG N ...............................................................................
7.1 PLACEMENT OF INJECTION WELLS ................................................................
7.2 INJECTION PARAM ETERS ..................................................................................
................................. 57
.............................. 60
..... 60
7.2.1 Injection Contents............ ........................................................................................
......... ......... 61
7.2.2 Injection Flowrates and Concentrations .....................................................
7.3 ESTIMATION OF BIOREMEDIATION TIME ...........................................
............................................. 66
8. CO N CLU SIO N ...............................................................................................
................................... 68
8.1 SUMMARY OF CONCEPTUAL D ESIGN ............................................. ................................................. 68
................................... 69
8.2 POTENTIAL PROBLEM S ................................................................................
..................................... 69
8.2.1 Clogging............................................................................................
8.2.2 Intermediate Toxicity.................................................................................................................... 70
8.2.3 Competitive Inhibition.................................................................................................................. 70
8.3 RECOMM ENDATIONS FOR FUTURE WORK .................................................................. .................... 71
............................................ 73
8.4 SUM MARY ..........................................................................................
9. REFEREN CES ................................................................................................
10. A PPEND IC ES...........................................................................................
.................................. 74
.......................................
78
10.1 APPENDIX A: DISSOLVED OXYGEN CONCENTRATION DATA FOR LF-1 (OPTECH, 1996b) ................... 79
10.2 APPENDIX B: EXPLANATION FOR EQUATIONS 7-1 AND 7-2 ............................................ 83
10.3 APPENDIX C: SPREADSHEET CALCULATIONS FOR CONCEPTUAL DESIGN........................................84
LIST OF FIGURES
FIGURE 2-1
FIGURE 2-2
FIGURE 2-3
FIGURE 2-4
FIGURE 3-1
LOCATION OF M M R..............................................................................
............................... 9
GEOLOGY OF UPPER CAPE COD .................................................................................................. 10
LOCATION OF LANDFILL CELLS (CDM FEDERAL PROGRAMS, 1995).......................................... 13
MAP OF LF-1 PLUME INUPPER CAPE COD.................................................................................. 16
UTILIZATION OF THE ORGANIC CONTAMINANT FOR ENERGY AND CELL PRODUCTION (NATIONAL
RESEARCH COUNCIL, 1993) ................................................................................................................... 21
FIGURE 3-2 ENZYME REACTIONS AS "LOCK AND KEY" (NYER, 1992)..................................
...... 23
FIGURE 3-3 TEMPERATURE RANGES FOR THREE CLASSES OF BACTERIA (NYER, 1992) ............................. 24
FIGURE 3-4 TYPICAL BIOREMEDIATION SCHEME IN THE SATURATED ZONE (KERR, 1994)............................26
FIGURE 4-1 PCE ISOCONCENTRATION CONTOUR MAP (CDM FEDERAL PROGRAMS CORPORATION, 1995)..30
FIGURE 4-2 TCE ISOCONCENTRATION CONTOUR MAP (CDM FEDERAL PROGRAMS CORPORATION, 1995).31
FIGURE 4-3 SPATIAL DISTRIBUTION OF DISSOLVED OXYGEN AND OTHER PARAMETERS (OPTECH, 1996a)35
FIGURE 5-1 IMPORTANT ELECTRON ACCEPTORS IN PRIMARY BIOTRANSFORMATIONS (KERR, 1995)...........38
FIGURE 5-2 PATHWAY FOR THE METHANOTROPHIC UTILIZATION OF METHANE (SEMPRINI ET AL, 1991 a)...41
FIGURE 5-3 EPOXIDATION OF TCE INCOMETABOLIC DEGRADATION (UNIVERSITY OF MINNESOTA
BIOCATALYSIS/BIODEGRADATION DATABASE, 1997) ..................................
42
FIGURE 5-4 ABIOTIC HYDROLYSIS OF THETCE EPOXIDE IN COMETABOLIC DEGRADATION (UNIVERSITY OF
MINNESOTA BIOCATALYSIS/BIODEGRADATION DATABASE, 1997)...............................
....... 43
FIGURE 5-5 HETEROTROPHIC DEGRADATION OF INTERMEDIATE AS THE FINAL STEP IN COMETABOLIC
DEGRADATION (UNIVERSITY OF MINNESOTA BIOCATALYSIS/BIODEGRADATION DATABASE, 1997).....43
FIGURE 5-6 RELATIONSHIP BETWEEN DEGREE OF CHLORINATION AND AEROBIC AND ANAEROBIC
DEGRADATION RATES (KERR, 1994) .................................................................................................
45
FIGURE 5-7 IDEAL SCHEMATIC FOR SEQUENTIAL ANAEROBIC/ AEROBIC DEGRADATION OF PCE AND TCE.47
FIGURE 6-1 INJECTION WELL SCHEMATIC USING PARAMETERS INWELTY-GELHAR SOLUTION..................53
FIGURE 6-2 DIMENSIONLESS BREAKTHROUGH CURVE FOR CONTINUOUS INJECTION AND CONSTANT
DISPERSIVITY (WELTY AND GELHAR, 1994)..................................................................................... 54
FIGURE 7-1 INJECTION WELL PLACEMENT.....................................................................................................58
FIGURE 7-2 CONCEPTUAL DESIGN OF INJECTION WELLS ...........................................
......... 59
FIGURE 8-1 BIOREMEDIATION WITH SEQUENTIAL ANAEROBIC/ AEROBIC BIOZONES ................................. 68
LIST OF TABLES
TABLE 2-1
TABLE 3-1
TABLE 3-2
TABLE 4-1
LANDFILLED MATERIALS (CDM FEDERAL PROGRAMS, 1995) ................................................. 14
MICROORGANISM POPULATION DISTRIBUTION IN SOIL AND GROUNDWATER (NYER, 1992)....... 19
MOLECULAR COMPOSITION OF ABACTERIAL CELL (NYER, 1992)...........................................20
CONTAMINANT MAXIMUM CONCENTRATIONS AND MCLS (CDM FEDERAL PROGRAMS
CORPORATION, 1995)...........................................................................................................
................ 28
TABLE 4-2 NITRATE VALUES FOR LF-1 (OPTECH, 1996a) ......................
.................... 33
TABLE 5-1 POTENTIAL FOR CHLORINATED ALIPHATIC HYDROCARBON BIODEGRADATION AS A PRIMARY
SUBSTRATE OR THROUGH COMETABOLISM (KERR, 1994) ........................................................... 39
TABLE 6-1 DEGRADATION RATE ESTIMATES FOR PCE AND TCE ......................................................... 55
TABLE 7-1 SUMMARY OF INJECTION CONTENTS, CONCENTRATIONS, AND FLOWRATES..................
66
TABLE 7-2 SUMMARY OF BIOREMEDIATION TIME ESTIMATES...........................................67
1. INTRODUCTION
1.1 Problem Statement
The main base landfill at the Massachusetts Military Reservation (MMR) on Cape
Cod, Massachusetts has served as MMR's primary solid waste disposal facility since
1941. Unregulated hazardous material disposal activities from 1941 to 1984 resulted in a
groundwater contaminant plume migrating from the landfill, containing chlorinated
solvents, such as tetrachloroethylene (PCE) and trichloroethylene (TCE), at levels above
statutory primary drinking water standards. Remediation of the contaminant plume to
concentrations below the Maximum Contaminant Levels (MCLs) is necessary in order to
prevent potential adverse effects of the contaminants to human health and the
environment.
1.2 Objective
The objective of this thesis is to develop a conceptual design for the in-situ
bioremediation of chlorinated solvents in the LF-1 plume. The design will rely on the
sequential anaerobic/aerobic degradation of PCE and TCE. Design parameters will
include the placement of wells to establish the aerobic and anaerobic biozones, the radii
of influence of the wells, selected substrates and nutrients, as well as recommended
concentrations and flow rates for the injected nutrients, oxygen, and substrates. The total
time for remediation of the plume to the MCLs will also be estimated.
1.3 Scope of Thesis
This thesis describes a conceptual design for the in-situ bioremediation of
chlorinated solvents in the LF-1 plume at the Massachusetts Military Reservation, located
in Upper Cape Cod. Chapter 2 provides an overview of the geology and hydrogeology of
Upper Cape Cod. It also includes a description of the location, history, and pollution
issues of the MMR, as well as an introduction to the main base landfill at MMR. Chapter
3 provides an overview of bioremediation, including basic definitions, the necessary
components for successful bioremediation, and the advantages of in-situ bioremediation
over common cleanup techniques such as pump-and-treat and air stripping. Chapter 4 is a
detailed examination of the subsurface conditions at LF-1. The distribution of essential
bioremediation components throughout the LF-1 plume is described. This chapter will
provide the basis for the conceptual design. Chapter 5 explains the processes of aerobic
and anaerobic degradation, and the utilization of these processes in concert to effectively
degrade trichloroethylene (TCE) and tetrachloroethylene (PCE). Chapter 6 discusses the
data gathered from various literature sources which are used to develop the conceptual
design. Furthermore, the chapter describes the analytical equations utilized in the
conceptual design. Chapter 7 provides the resulting conceptual design, including injection
well placement, injection contents, injection flowrates and concentrations, and total
bioremediation time. Finally, Chapter 8 will summarize the results of the conceptual
design. Potential problems with the design are also discussed,
along with
recommendations for future work which could improve the feasibility and costeffectiveness of the design.
2. SITE DESCRIPTION
2.1 Location and History
The Massachusetts Military Reservation (MMR) is located in the upper Western
portion of Cape Cod, Massachusetts, as shown in Figure 2-1. The MMR occupies
approximately 22,000 acres within the towns of Bourne, Sandwich, Mashpee, and
Falmouth in Barnstable County.
0
Figure 2-1 Location of MMR
Military activity began at the base in 1911, but the bulk of the activity has occurred since
1935, with operations by the U.S. Army, U.S. Navy, U.S. Coast Guard, U.S. Air Force,
Massachusetts Army National Guard, and U.S. Air National Guard. The heaviest activity
at MMR occurred from the 1940s, when U.S. Army activities intensified due to World
War II, to the 1960s and 1970s, when the U.S. Air Force maintained heightened aircraft
operations. (CDM Federal Programs Corporation, 1995)
2.2 Geology
Three types of major geologic formations make up the stratigraphy of the Upper
Cape: the Mashpee Pitted Plain (MPP), the Buzzard's Bay Moraine (BBM), and the
Sandwich Moraine (SM), shown in Figure 2-2.
.r
IULLzII
n..
1-
-..
C3......:..
Ll...:..
Outwa!
Buzzard's E
Moraine
Figure 2-2 Geology of Upper Cape Cod
The BBM and SM units have not been characterized in detail, and are reliably known
only to consist of poorly sorted sand and gravel with localized deposits of silt and clay.
(Masterson et al., 1994, 1996) To the northwest of the BBM lies the Buzzard's Bay
Outwash (BBO). The BBO is thought to simply be a continuation of the MPP, with
similar soil layers and properties. (Masterson et al., 1996) The MPP, which lies between
the BBM and SM, consists of fine to coarse- grained sands that form a broad outwash
plain. The bedrock in Upper Cape Cod lies approximately 300 feet below ground surface.
(CDM Federal Programs Corporation, 1995)
2.3 Hydrogeology
Upper Cape Cod, including MMR, has a single groundwater system which is an
unconfmed aquifer. The aquifer, which ranges from 50 to 175 feet in thickness, is
recharged by infiltration from precipitation. It is bounded by the Atlantic Ocean on three
sides, with groundwater discharging into Cape Cod Bay on the north, Buzzards Bay on
the west, and Nantucket Sound on the south. The water table, which resembles a mound,
has its high point beneath the northern portion of MMR, near the site of the FS-12 plume.
The hydraulic gradient across the MMR ranges from 0.0014 to 0.0018 ft/ft. (CDM
Federal Programs Corporation, 1995)
The hydraulic conductivity of the MPP outwash soils are as high as 380 ft/day.
The hydraulic conductivity of the fine-grained sediments underlying the outwash are only
2 to 10% of that value. Most of the regional groundwater flow occurs in the upper,
coarse sand and gravel layer. Horizontal flow velocities range from 1 to 3.4 ft/day.
(CDM Federal Programs Corporation, 1995)
2.4 Environmental Pollution at MMR
In 1982, the Department of Defense developed the Installation Restoration
Program, whose purpose was to investigate and clean up environmental pollution at
MMR facilities. The MMR was placed on the United States Environmental Protection
Agency (USEPA) National Priorities List (NPL) in November 1989, indicating that the
contamination at the reservation posed a serious threat to human health and the
environment.
Since May 1996, the Installation Restoration Program has been managed by the
Air Force Center for Environmental Excellence (AFCEE). A series of remedial studies
and activities are currently being conducted under the Program in accordance with the
guidelines and procedures of the USEPA Superfund Program and the National
Contingency Plan (NCP). To date, the Installation Restoration Program has spent over
$130 million on investigation and cleanup at the reservation. Currently, 78 separate sites
at the MMR are identified as environmental contamination sources, including fuel and
chemical spill areas, landfills, coal yards, storm drains, and firefighter training areas, and
10 major groundwater contaminant plumes, including the main base landfill plume,
known as LF-1. (Massachusetts Department of Environmental Protection, 1996)
2.5 Characteristicsof the Main Base Landfill
The main base landfill covers approximately 100 acres in the southwestern section
of the Massachusetts Military Reservation. It was used by the Army, Air Force, other
military branches, and the towns of Bourne, Falmouth, and Sandwich as a place of
disposal from 1940-1984. Unregulated and unmonitored disposal to the landfill was a
common occurrence. (Kostek, 1997)
The landfill can be broken up into 6 distinct cells: 1947, 1951, 1957, 1970, post1970, and Kettle Hole, as seen in Figure 2-3.
d
-
~WWlROM
rT.C PHOMInAP")
ccw~lm
roavxncm 2 PISET
RAbMA2LOCEFICIS
(UGA.eMUOL
Figure 2-3 Location of Landfill Cells (CDM Federal Programs, 1995)
wei
,0
m
0SAL 1ffl
The cells are named for the date in which they were last used. The post-1970 cell ceased
to be used in June 1989. The Kettle Hole is a naturally occurring formation which was
used for dumping waste for many years. The highest activity at the base occurred from
1940-1946, when it was under Army control and from 1955-1970, when it was under Air
Force control. It is believed that these times of highest activity coincided with the highest
rate of waste generation and disposal. All of the information about the landfill was
obtained from interviews of base employees during the preliminary records search
(Hazwrap, 1987). This is the only source of information about the landfill since no
written records were kept about waste disposal methods.
2.5.1 Landfilled Materials
Many of the base activities generated wastes. The main wastes that were produced
and believed to have been disposed of in the landfill are listed in Table 2-1.
Table 2-1 Landfilled Materials (CDM Federal Programs, 1995)
Wastes
General refuse
Herbicides
Transformer oils
Blank small arms ammunition
Paint thinners
DDT powder
Municipal sewage sludge
Fuel tank sludge
Solvents
Fire extinguisher fluids
Paints
Batteries
Hospital wastes
Coal fly ash
Possible live ordnance
These wastes are believed to have been disposed of by the trench method for
landfilling, as indicated by recent waste disposal practices and the surface topography at
the older cells. The waste was buried in linear trenches and covered daily with the soil
that was excavated from the trench. (CDM Federal Programs, 1995)
2.5.2 Current Status of the Landfill
Since 1989, when waste disposal in the post-1970 cell was ceased, all MMR
waste has been sent to the SEMASS incinerator in Rochester, MA for disposal. Small
quantities of demolition debris are still disposed of in the Kettle Hole. (CDM Federal
Programs, 1995) Currently, the landfill is mostly covered with vegetation native to the
area.
The 1970, post-1970, and Kettle Hole cells have been capped to prevent any
further contamination from migrating from the landfill. An alternate closure has been
recommended for the 1947, 1951, and 1957 cells. Alternate closure involves leaving the
waste in the cells intact beneath a vegetative cover and providing groundwater monitoring
and landfill surface maintenance for thirty years. Post- closure management plans are
being developed for these cells. (Leon, 1997)
2.5.3 Contaminant Plume Resulting from the Landfill
The landfill was identified as a potential contaminant source in 1979 when
sampling at a drinking water well downgradient of the landfill demonstrated volatile
organic carbon (VOC) concentrations exceeding drinking water standards (Metcalf &
Eddy, 1983). This discovery led to further sampling for the assessment of the nature and
extent of the contamination due to the landfill. Some sampling wells were placed within
the boundaries of the landfill, but not directly within any of the cells, due to the possible
presence of buried live ordnance in the landfill. The sampling determined that there is a
VOC plume that extends to the southwest of the landfill, beyond the MMR boundaries, as
shown in Figure 2-4.
Figure 2-4 Map of LF-1 Plume in Upper Cape Cod
The plume begins at a depth of 40 feet below the landfill. In October 1995 the LF-1
plume was measured to be approximately 16,500 feet long in the southwest direction,
6000 feet wide, and over 90 feet thick. By this same time over 22 billion gallons of
groundwater had been contaminated by the plume. The velocity of the LF-1 plume is
estimated to be 544 feet/year. The main VOCs of concern in the plume are
trichloroethylene (TCE) and tetrachloroethylene (PCE). Carbon tetrachloride (CC14) has
also been found in many of the wells, but not on a consistent basis. The VOC plume
exceeds the Maximum Contaminant Levels (MCLs) of 5 parts per billion (ppb) for
groundwater.
2.5.3.1 Current Status of LF-1
A groundwater extraction, treatment and reinjection (ETR) system was at 60%
design for the LF-1 plume in January 1996, but was put on hold due to unacceptable
groundwater pumping rates. The ETR pilot test system had been proposed by AFCEE for
the southern lobe of LF-1, with a scheduled construction startup in June 1997 and system
startup in March 1998. This project has now been indefinitely delayed. A recirculating
well pilot test system was proposed by AFCEE for the northern lobe of LF-1. It was
scheduled for construction startup in December 1996 and system startup in May 1997,
but this project has also been indefinitely delayed. (Massachusetts Department of
Environmental Protection, 1996)
Currently, no remedial actions are being implemented for the LF-1 plume. The
nature and extent of the contamination require that a remediation system be installed as
quickly as possible, to prevent further spreading of the plume. This thesis examines an insitu bioremediation design scheme as an alternative to ETR and recirculating wells for the
remediation of LF-1.
3. BIOREMEDIATION
3.1 Definition
Bioremediation involves the use of microorganisms to convert contaminants to
less harmful species in order to remediate contaminated sites. Microorganisms usually
degrade organic compounds to obtain energy that is conserved in the carbon-carbon
bonds of the compounds, and to use the organic carbon as building blocks for new
microbial cells.
3.2 Microorganisms
Bacteria, viruses, fungi, algae, protozoa, and metazoa are among the
microorganisms that exist on earth. Microorganisms can be classified into two general
categories of cell structure: eucaryotic or procaryotic. Eucaryotic microorganisms, which
have a relatively complex cell structure, include fungi, algae, and protozoa. With a more
simple cell structure, prokaryotic microorganisms include bacteria.
Protozoa and metazoa do not have important degradative roles, and are not
usually considered for bioremediation applications. (Nyer, 1992) Fungi comprise a
diverse group of organisms, such as molds, mildews, and mushrooms, but are
predominately located in soil or dead plant material.
Bacteria have been on earth for 3 billion years. They are the most prevalent and
diverse microorganisms on earth. Approximately 85% of bacterial existence to date
occurred before the continental plates began to separate, thereby providing the organisms
with a long time to evolve, adapt, and disperse. (National Research Council, 1993)
Bacteria have excellent adaptation and survival capabilities, which make them an ideal
candidate for bioremediation, since the contaminated sites often have less than optimal
conditions. These characteristics help to explain why bacteria usually outnumber the
other organisms found in soil and groundwater, as shown in Table 3-1.
Table 3-1 Microorganism Population Distribution in Soil and Groundwater (Nyer, 1992)
ORGANISM
_
Bacteria
Fungi
Algae
Bacteria
Bacteria
POPULATION SIZE
:_
_(TYPICAL)
Surface Soil (cells/g soil)
0.1-1 billion
0.1-1 million
10,000-100,000
Subsoil (cells/g soil)
1,000-10,000,000
Groundwater (cell/mL)
100-200,000
POPULATION SIZE
(EXTREME)
> 10 billion
20 million
3 million
200 million
1 million
3.3 Environmental Requirements
In order for biodegradative processes to occur, the microorganisms require the
presence of certain nutrients, electron acceptors, and substrates. Several other
environmental conditions also affect the effectiveness of the microorganisms' degradative
capabilities.
3.3.1 Nutrients
The molecular composition of the bacterial cell is an indicator of the bacteria's
requirements for growth. Approximately 80-90% (by weight) of the cell is composed of
water, which is therefore the main nutrient for the cells. Table 3-2 shows that the solid
portion of the cell is composed mostly of carbon, oxygen, nitrogen, hydrogen, and
phosphorus.
Table 3-2 Molecular Composition of a Bacterial Cell (Nyer, 1992)
Element
Percentage of Dry Weight
Carbon
Oxygen
Nitrogen
Hydrogen
Phosphorus
Sulfur
Potassium
Sodium
Calcium
Magnesium
50
20
14
8
3
1
1
1
0.5
0.5
Chlorine
0.5
Iron
Others
0.2
-~0.3
The microbes derive carbon from the organic compounds they destroy. Oxygen
and hydrogen are provided by the groundwater. The other major nutrients required by the
microorganisms for growth and energy are nitrogen and phosphorus. The most common
sources of nitrogen are ammonia and nitrates. Ammonia can be directly utilized for amino
acid synthesis, while nitrates are reduced to ammonia and then assimilated into the
synthesis. Phosphorus, mostly in the form of phosphates, is used by bacteria to synthesize
phospholipids and nucleic acids, as well as for the energy transfer reactions of adenosine
triphosphate (ATP). An adequate supply of these nutrients must be available to the
microorganisms for the bioremediation process to be effective.
3.3.2 Electron Acceptor
In order for microorganisms to transform nutrients to forms that are useful for
incorporation into cells and synthesis of cellular material, microorganisms need a source
of energy. Microbes derive much of their energy from oxidation- reduction reactions,
where a transfer of electrons from an electron donor to an electron acceptor occurs,
thereby resulting in the release of energy. Figure 3-1 demonstrates the common
utilization of organic contaminants as the electron donor.
Organic
Contaminant
Figure 3-1 Utilization of the Organic Contaminant for Energy and Cell Production (National
Research Council, 1993)
There are a number of different compounds that can act as electron acceptors, including
oxygen (O2), nitrate (NO'), iron oxide (Fe(OH)3), sulfate (SO4"2), and carbon dioxide
(CO 2). Aerobic bacteria can only utilize oxygen as an electron acceptor, while anaerobic
bacteria use the other compounds as electron acceptors. Oxygen is the optimal electron
acceptor because microorganisms can derive the most energy from oxidation-reduction
reactions with oxygen. Sulfate and carbon dioxide provide the least amount of energy to
the microbes. Figure 5-1 illustrates the difference in electron acceptors.
3.3.3 Substrate
Electron donors which participate in microbe-catalyzed oxidation-reduction
reactions are also called substrates. Reactions are catalyzed when the substrate collides
and binds to the active site of an enzyme. Enzymes are proteins, produced by the bacteria,
which perform highly specific reactions. A bacterial cell contains approximately 1000
enzymes. (Nyer,1992) Substrate activation allows for the enzyme to react and produce
products and restore the enzyme. Enzyme reactions can be understood with the lock and
key representation.
Substrate
Enzyme: Active Site
on Surface
Free Enzyme
Figure 3-2 Enzyme Reactions as "Lock and Key" (Nyer, 1992)
Figure 3-2 shows how only an enzyme with the right shape can function as a key for the
oxidation-reduction reactions. Although it is not shown on Figure 3-2, the fit between the
enzyme and substrate must be three-dimensional and precise.
When microorganisms consume a compound to satisfy its energy and cell growth
needs, the compound is considered a primary substrate. This is the usual process for
organic decomposition in nature. However, in the environment, the microorganisms will
not directly utilize organic compounds that do not provide them with significant energy
for growth. However, some of these organic compounds can be biotransformed by
microorganisms as secondary substrates through a process known as cometabolic
transformation, which is explained in sections 5.2 and 5.3.
3.3.4 Other Environmental Conditions
There are other factors which will affect the biodegradation process, including
temperature, pH, and the concentration range of the contaminant.
3.3.4.1 Temperature
Temperature is an important microorganism growth factor. Every microorganism
has a minimum temperature below which growth does not occur, a maximum temperature
above which the proteins and cellular components of the microbes will become
inactivated, and an optimum temperature at which growth is the most rapid. There are
three categories of bacteria, thermophiles, mesophiles, and psychrophiles, which thrive at
different temperatures, as shown in Figure 3-3. Microorganisms that are cultivated in
aquatic environments are mostly mesophiles, which grow in a range of 10"C to 45TC.
3.0
4
1.0
Growth
Rate
(Generations/hr)
0.3
.0.
10
20
30
40
50
60
Temp•rmtureoc
Figure 3-3 Temperature Ranges for Three Classes of Bacteria (Nyer, 1992)
70
When designing a bioremediation scheme, it should be noted that since these microbes
can grow at a wide range of temperatures, large temperature fluctuations pose a greater
threat to biological activity than the maintenance of a particular temperature.
3.3.4.2 pH
The optimal pH for microbial growth is dependent on the specific microorganisms
and their biological pathways. Many enzymes can only be produced by microbes in the
proper pH range. Aerobic microorganisms are usually able to tolerate a wider pH range,
whereas many anaerobic bacteria grow efficiently in a very narrow pH range. The optimal
pH for bacteria in groundwater is between 6.5 and 7.5, values which are close to their
intracellular pH. (Nyer, 1992)
3.3.4.3 Concentration Range of Contaminant
When contaminants in the groundwater are secondary substrates, whereby the
contaminant and the primary substrate are degraded by the same enzyme, the contaminant
and primary substrate can compete for the enzyme's active sites. This process, known as
competitive inhibition, will occur if the contaminant concentration is too high. The
maximum allowable concentration for no inhibition depends on the specific compound,
but ranges between 10 mg/L and 100 mg/L for chlorinated compounds. (Kerr, 1994) High
primary substrate concentrations have also been found to significantly inhibit the
degradation of contaminants, as explained in section 8.2.3.
3.4 In- Situ Bioremediation
In-situ bioremediation of contaminants in groundwater allows for the on- site
destruction of contaminants. The in-situ system, depicted in Figure 3-4, typically consists
of extraction wells, where the extracted groundwater is treated with substrate. electron
acceptor, and nutrients, and injection wells which are used to reinject the treated water.
ScOur=
GrCmd-Waft
Tratment
Nutrients
r
I
r
M Ionng
Well
-i
ll
Gound.WaLer Gradt
'W
--
W
Nknimoing Well
Iw
m
m
Recovery Well
mrýW
Soil Contammation
GWW
Figure 3-4 Typical Bioremediation Scheme in the Saturated Zone (Kerr, 1994)
3.4.1 Advantages over Remedial Alternatives
In-situ bioremediation has the potential to provide a more effective and
inexpensive alternative to traditional remediation methods. It can completely destroy the
contaminant rather than transfer it to another medium, which is common in re=ediation
technologies like air stripping. It typically requires less treatment time than pump-andtreat remediation. It also offers the opportunity to use the subsurface as a bioreactor,
whereby the necessary bioenhancers are injected into the contaminated groundwater and
the remediation occurs in the aquifer, which eliminates the need to pump large quantities
of water to the surface.
4. CHARACTERIZATION OF THE LF-1 PLUME
4.1 Plume Characterization
In order for bioremediation of the contaminants to occur, microorganisms require
the presence of certain substances and conditions. Examination of the characteristics of
the LF-1 plume will determine what additional substances and conditions are needed to
stimulate or enhance bioremediation.
4.2 Spatial Distributionof Contamination
The two main contaminants of concern at LF-1 are tetrachloroethylene (PCE) and
trichloroethylene (TCE). As Table 4-1 shows, both contaminants are present at levels
which significantly exceed Maximum Contaminant Levels (MCLs).
Table 4-1 Contaminant Maximum Concentrations and MCLs (CDM Federal Programs
Corporation, 1995)
COMPOUND
MAXIMUM DETECTED (pg/L)
PCE
TCE
65
64
MCL
_1_gfL)
5
5
The TCE and PCE isoconcentration contour maps (Figures 4-1 and 4-2) provide
the spatial distribution of the contaminants in the LF-1 Plume. The PCE plume contains
three areas of highest measured concentration, located at monitoring wells GB22, MW35,
and MW103, with average concentrations of 30 jg/L, 48 pLg/L and 65 pg/L, respectively.
The TCE plume contains three areas of highest measured concentration, located at
monitoring wells MW37A, MW38, and MW31, with average concentrations of 19 lag/L.
26 ýtg/L, and 64 ipg/L, respectively.
~LY
1"-500
-)---C
•1; n
IR'IM
4p
brr
* FI~
-
nnrsurm
mpr y
fiu
ra0mr
w
Figiurc 4-1 II'CE Isoconlccntrationl Contour Malp (CI)M Fcdcrnl Progrlams Corporation, 1995)
30
KEY
NOTES:
S4LC1TD
CItOA#4ALtD
rr~
gIjM
OVERHEAD
ELECTRIC
POWERLINES
~~itLxDw
I'
-,
alawnm
pe
inmcoeen
s*
e
Figure 4-2 TCE Isoconcentration Contour Map (CDM Federal Programs Corporation, 1995)
31
4.3 Spatial Distributionof Nutrients
The only available nutrient data demonstrates the distribution of nitrate
throughout the plume. Since no phosphate data is available, it will be assumed that the
plume is depleted of phosphorus, for design purposes. Further design modifications
would require a detailed analysis of background phosphorus concentrations in the plume.
Most of the plume has a sufficient supply of nutrients in the form of nitrate, with only ten,
out of seventy four, monitoring wells measuring non-detectable levels. The detectable
concentration of nitrate is shown in Table 4-2 to range between 0.07 mg/L (at MW-22)
and 1.20 mg/L (at MW-35). This conceptual design assumes that the background
concentration of nitrate remains constant, so that a nitrogen source is only added to
locations where the background levels are below the requirements of the bacteria, which
are indicated in section 6.5.
Table 4-2 Nitrate Values for LF-1 (OPTECH, 1996a)
_
Nitrated
Site
Well
Nwnber
Nttrite
(mOtI)
Up'grdient f Fence I
LF.I
MW.707
0.09
MW-17A
MW.17B
MW-19
Well Fence 1.1
MW-9
I..I
MW-20A
LE-1
MW.208B
IE-I
MW-O0C
LF-I
LFI.1 MW-20Z
CS-9 : MW-I
MW-35
CS-Ia
MW.36
CS-la
MW-61
LF
I
MW.-71
LF-I
MW-705
LF.
ND
0.27
0.10
0.60
0.22
0.85
0.09
0.23
ND
ND
0389
Well Fence 1.2
CS-10
L.lI
MW-48
MW.701A
Nitram/
Nltrite
(m•nl)
0.25
0.25
LF1CS-10
CS-10
CS-10
LF-I
LF.I
LF-I
LF-1
LF.I
WT-25
MW-42A
MW-42B
MW42C
MW.103A
MW-103B
MW-t03Z
MW.104A
MW-104B
0.46
ND
0.42
033
0.46
0.23
0.14
0.60
0.54
Between Fences 2 & 3
LF-I
LF-I
LF-I
MW-25
MW-25A
MW-26
LF-.
MW-28Z
LF-I
MW-29
LF-I
MW.31A
LF-I MW.31B
LF-I MW.31C
LF.I MW-601A
LF-I
MW-601B
LF.
MW.601C
LF-I
MW-602B
LF.I MW-602C
Site
se Well
Nmiber
0.J8
0.96
0.32
030
0.13
0.23
0.03
0.08
0.70
0.47
0.59
1.10
0.67
0.19
LF*I
LF-I
LF-I
LF-I
LF-I
LF-I
LF-1
LF-I
LF-I
LF-I
LF-I
GB-20
MW-38
MW-38A
MW-38Z
MW.39A
MW-40
MW-40A
MW-l4
MW-.4
MW-S5
MW.47
LF.I
LF-I
II
I-
MW.22A
MW-23
MW-24A
MW-24B
MW-32
MW-33
MW-34
0.07
0.77
ND
ND
0.60
0.48
0.78
.F-I
LF-I
LF-I
LF-I
LF.I
LFl.I
, ,I
MW.35
MW-36B
MW-37A
MW-43
0G-22
WT-26
1.20
0.92
030
0.80
0.21
ND
I
i r
0.36
ND
0.72
0.18
0.29
0.23
0.75
029
032
0.71
0.47
MW-6
MW-46A
0.62
0.13
MW-50A
MW-50B
MW-51
MW-52
MW-53
0.62
0.40
0.62
059
0.37
037
Well Fence 5
LE-I
LE-I
LF-I
LF-I
LF-l
LF-I
MW.54
Other Wells
LI.1
LF-I
.LF-I
LF.I
LF-I
LF-I
LF-I
(mi,)
Between Fences 4 &5
Well Fence
Well Fenc 2
itrtt
Well Fence 4
Well Fence 2 (co•.)
Wel Fence I
LF-I
LF-I
LF-I
Site
Well
Nmnber
__
LF-I
LF-I
WT-28
WT.29
4.4 Spatial Distributionof Oxygen
The plume overall is fairly aerobic, with values ranging from non-detectable to
approximately 10 mg/L. For design purposes, the wells which do not have measured
dissolved oxygen levels will be considered anaerobic, however a more detailed design
will require the assessment of oxygen levels at those locations. The spatial distribution of
dissolved oxygen is illustrated in Figure 4-3; additional dissolved oxygen data from
monitoring wells is shown in Appendix A.
Figure 4-3 Spatial Distribution of Dissolved Oxygen and Other Parameters (OPTECH, 1996a)
35
4.5 Spatial Distributionof Substrates
The only primary growth substrate that has been detected in the plume is toluene,
which was present in low concentrations (0.15 pg/L to 7.1 gg/L) at a few wells. (CDM
Federal Programs Corporation, 1995) Other substrates, including phenol, were not
detected. Based on this information, the design will be developed with the assumption
that there is no primary substrate present in the plume.
4.6 Spatial Distributionof Microorganisms
In this bioremediation design of the LF-1 plume, it is assumed that there is a
viable microbial population in the groundwater, and the bacteria are the main source of
microorganisms in the aquifer. The assumption of viability is valid, given that historically
less than 1% of sites have been found to lack a viable microorganism community capable
of biodegrading a wide range of hydrocarbons. (Kerr, 1994)
4.7 Spatial Distributionof Temperature and pH
The temperature in the plume ranges between 10*C and 20*C, which is within the
temperature range recommended for optimal bioremediation. (See Section 3.3.4.1) The
pH of the plume ranges between 5.5 and 7, which is in the optimal range for the
microorganisms to perform the biodegradation processes. (See Section 3.3.4.2) Figure 4-3
illustrates the spatial distribution of temperature and pH in the LF-1 plume.
5. SEQUENTIAL ANAEROBIC/ AEROBIC DEGRADATION
OF CHLORINATED SOLVENTS
5.1 Biodegradation of Organic Compounds
Organic compounds can be biotransformed by microorganisms through two main
processes: (1) primary substrate utilization or (2) cometabolism. When the organic
compound is used as a primary substrate, the microorganism consumes the compound
because it derives food, in the form of organic carbon, and energy, in the form of
reduction-oxidation reactions, from the process. The microorganisms convert the
compound into harmless products, primarily CO,, cell mass, inorganic salts, and water.
The microorganisms are driven to degrade the organic compounds due to their need for
utilizing reduced forms of nutrients for nutrient incorporation into cells and for the
synthesis of cell polymers. The reduction of nutrients requires energy and electrons,
which the microorganisms acquire from the degradation of organic compounds. When the
organic compound is utilized as a primary substrate, it becomes the electron donor in a
reduction-oxidation reaction involving a terminal electron acceptor, which can differ
depending on whether or not the conditions are aerobic or anaerobic, as demonstrated by
Figure 5-1.
1.0
C
0
Aerobic
(Oxygen as
ctionn Acceptor)
(
0o,+4H+ +4.- - 2H
2
2NO; + 12H+ +10e -+ N2 + 6H2 0
>0.5 - MnO2(s)+HCO, +3H +2e
I<
- IMnCO
-
C=
C
0
3(s)+ 2H20
C
E
=
So
+
0
FeOOH(s) +HC +2H+
2H'
-
-+
C=
il
FeCO 3 (s) + 2H 2 0
-
SO' + 9H+ + 8e
HS' + 4H 0
CCO. + 8H+ + 8es -+ CH4 + 2H2
TypicalPrinmary
Substrates
(Elecron onors)
2C02 +8H +8e- - CH
3COOH +2H
20
2H* + 290-+ H2
Figure 5-1 Important Electron Acceptors in Primary Biotransformations (Kerr, 1995)
This transfer of electrons provides energy for the reduction of nutrients and the resulting
synthesis of cellular material or incorporation into cells. The following is an example of
an organic compound, benzene, being used as a primary substrate for growth by
microorganisms, which was illustrated in Figure 3-1:
C6H6 + 7.5 0 2
C6H 6+ 1.5 HC03- + 1.5 NH44
6 CO2+ 3 H 20
1.5 C5H70 2N + 1.5 H20
In the above example, 02 is the terminal electron acceptor and CsH 70 2N is the
synthesized cellular material. A portion of the organic contaminant is used as a primary
energy source that is converted to end products, and another portion is used to synthesize
the cellular material.
Few chlorinated aliphatic hydrocarbons are utilized by microorganisms as a
primary growth substrate. Table 5-1 illustrates that dichloromethane (CH2CI2), 1-2
dichloroethane
(CH 2C1CH2C1),
chloroethane
(CH 3CHC1),
and
vinyl
chloride
(CH2=CHCI) are the few exceptions which have been shown to be available as primary
growth substrates.
Table 5-1 Potential for Chlorinated Aliphatic Hydrocarbon Biodegradation as a Primary
Substrate or Through Cometabolism (Kerr, 1994)
Primary Substrate
Cometabolism
Compound Name
Chemical
Aerobic
Anaerobic
Aerobic
Anaerobic
Potential
Potential
Carbon Tetrachloride
Chloroform
Dichloromethane
Trichloroethane
1,1 Dichloroethane
Formula
CCI 4
CHCl 3
CH2 Cl 2
CH 3 CCl 3
CH 3 CHCI2
Potential
XXXX
XX
Yes
Yes
Potential
0
X
XXX
X
X
1,2 Dichloroethane
CH2CICH 2CI
Yes
X
X
Yes
XX
XXXX
XX
Chloroethane
CH 3CH 2 CI
Tetrachloroethylene
CC12=CC12
0
XXX
Trichloroethylene
Dichloroethylene
1,1 Dichloroethylene
CHCI=CC12
CHCI=CHCI
CH2=CCI2
XXX
XXX
X
XX
XX
XX
Vinyl Chloride
CH2=CHCI
XXXX
X
Yes
O:No real potential, X-XXXX: Little to excellent potential, Bold: PCE and TCE.
These findings suggest that only the less chlorinated compounds are used by
microorganisms for energy and growth. The majority of chlorinated aliphatic
hydrocarbons are biodegraded by the second process, known as cometabolic degradation.
5.2 TCE: Aerobic Cometabolic Degradation
Cometabolic degradation occurs when a compound is inadvertently degraded by
an enzyme that is produced by the microorganism for other purposes. It is a fortuitous
process since the microorganisms derive no direct benefit from the degradation, and it
might even be harmful to them. Many common chlorinated contaminants in the
groundwater can be cometabolically biodegraded.
Even though trichloroethylene (TCE, CCI,=CHCI) can not serve as a primary
growth substrate, it can be cometabolically transformed by methanotrophic bacteria,
microorganisms that oxidize methane for energy and growth. The reaction occurs in an
aerobic environment, where TCE is the electron donor and 02 is the terminal electron
acceptor. When the primary growth substrate methane is available to the bacteria, the
bacteria will produce an enzyme called methane monooxygenase (MMO) which catalyzes
the initial oxidation of methane to methanol, as shown in Figure 5-2. Energy is derived
from that reaction and new enzymes are formed to drive the oxidation process to
continue, whereby formaldehyde, formate, and ultimately carbon dioxide is produced.
CELL CONSTITUENTS
NADH
E
t2
£1
4
CH
CH
NAD
N 1HCHO "
7
XH
X
NAD
EA
N
CO: * H20
HC00Hn
NADH
NA
NAD
NADHH
El - METHANE MONOOXYGENASE
(E :METHANOL DEHYOROGENASE OR
ALCOHOL OxiDASE
Et : FORMALDEHYDE DEHYDROGENASE
4
: FORMATE DEHYOROGENASE
x x A PROTON AND ELECTRON CARRIER
Figure 5-2 Pathway for the Methanotrophic Utilization of Methane (Semprini et al, 1991a)
The MMO enzyme has a low substrate specificity and is therefore capable of initiating
the oxidation of many halogenated compounds, including TCE. MMO is a dinuclear iron
enzyme which catalyses the conversion of TCE into an epoxide by breaking its own
oxygen-oxygen bond and inserting one oxygen molecule into a carbon-hydrogen bond.
Figure 5-3 demonstrates the epoxidation process of TCE by MMO.
'YFe,
IYFe-
'10
C•I j
IIIFe,
OH
IIIFe'
IVFeOH
0
OH
HCI
IIIFe,
C
III'Fe
H
IIIF e'O
FeH C I
•poxidation
CI
iIiFe •' OH
H
CI
Figure 5-3 Epoxidation of TCE in Cometabolic Degradation (University of Minnesota
Biocatalysis/Biodegradation Database, 1997)
The epoxidation of TCE by MMO is followed by the abiotic hydrolysis of the highly
unstable epoxide into nonvolatile compounds, as shown in Figure 5-4.
Cl
0
CI
O
5%
Dichloroacetate
CO
methane
monooxygenase
0
53%
C T E epode
TCE eposide
2 H2 O0
2 M11
35%
Formate
+
0
0
5%
Glyoxylate
Figure 5-4 Abiotic Hydrolysis of the TCE epoxide in Cometabolic Degradation (University of
Minnesota Biocatalysis/Biodegradation Database, 1997)
Finally, the compounds are biotically degraded to CO2, chloride, and water. In other
words, microorganisms derive energy from these intermediates by forming specific
enzymes to degrade them. Figure 5-5 demonstrates the pathway of one of the
intermediates. The ability of the bacteria to obtain energy from these compounds
indicates that they might serve as substitutes for methane to drive the cometabolism of
TCE.
o
Formate
formate
dehydrogenase
NAD +
CO2
NADH
Figure 5-5 Heterotrophic Degradation of Intermediate as the Final Step in Cometabolic Degradation
(University of Minnesota Biocatalysis/Biodegradation Database, 1997)
Most of the work seen in literature and experiments to date has been devoted to
the cometabolism of TCE using methanotrophs. However, in addition to methaneoxidizing bacteria and the intermediates described above, there are numerous other types
of substrates that have been found to catalyze the cometabolic degradation of TCE and
other chlorinated compounds, including phenol, propane, ethylene, toluene, cresol,
ammonia, isoprene, and vinyl chloride. (Kerr, 1994)
Several recent research projects have determined that phenol-utilizing bacteria are
more effective than methanotrophic bacteria for the cometabolic transformation of TCE.
(Kobus, 1996) In a similar manner to methane, phenol (hydroxybenzene) is oxidized to
dihydroxybenzene, which is transformed to products used for cell synthesis and energy
and, ultimately, to CO 2.
For cometabolism to occur, an active population of microorganisms having the
cometabolizing enzymes must be present. Therefore it is important to have the proper
growth substrate available to the microorganisms in order for the enzymes to be
produced.
5.3 PCE: Anaerobic Cometabolic Degradation
Aerobic cometabolic degradation is not effective on saturated chlorinated
aliphatic hydrocarbons like tetrachloroethylene (PCE, CC12=CC1
2 ), where the organic
compound is completely chlorinated. The oxygenase enzyme produced for cometabolism
reacts with unsaturated chlorinated compounds like TCE by adding oxygen to a C-H
bond to form an epoxide, a highly unstable intermediate that further degrades to harmless
products. With a saturated compound like PCE, the oxygenase will add the oxygen to the
C-Cl bond, and substitute a chlorine group with a hydroxyl group, resulting in the
formation of trichloroethanol, a chemically stable and toxic compound (CCIlCCIOH). In
general, the less chlorinated the compound is, the more susceptible it is to aerobic
degradation. Conversely, as Figure 5-6 shows, the more chlorinated compounds such as
PCE are effectively degraded with another cometabolic process, known as reductive
dechlorination.
o
6.
-0
Uo
o
Degree of Chlorination
Monochlorinated
ca--sa
--
Polychlorinated
-4
0.25
Figure 5-6 Relationship between Degree of Chlorination and Aerobic and Anaerobic Degradation
Rates (Kerr, 1994)
In an anaerobic environment, highly chlorinated aliphatic hydrocarbons, such as
PCE, are degraded to less chlorinated compounds by reductive dechlorination. Reductive
dechlorination occurs when anaerobic bacteria produce an enzyme to react with a primary
growth substrate, which then fortuitously catalyzes the reductive dechlorination of PCE.
In the reaction, PCE acts as the electron acceptor, whereby a chlorine atom is replaced
with a hydrogen atom, and the primary substrate acts as the electron donor. Many
different electron donors have been shown to be effective in reducing PCE, including
lactate, methanol, hydrogen, formate, acetate, and glucose. (Kerr, 1994)
One microbial system (DiStefano et al, 1991) which showed complete
transformation of PCE to ethene (C2H4) involves the use of methanol as the primary
electron donor and ammonium and phosphate as nutrients for the bacteria. The
stoichiometric relationships for this system are as follows:
C2C14 (PCE) + 1.33CH 3OH (methanol) + 1.33H,O
3CH OH + 2.25HCO0'
-
C2H4 (ethene) + 4HCI + 1.33CO,
a 2.25CH 3COO (acetate) + 0.75CO, + 3.75H20
2.25CH 3C0 + 0.056NH 4+ + 2.02H20 + 0.083CO 2 --
0.056C5 H,7 N (biomass) + 2.1 1CH 4+2.19HCO3-
Although the phosphorus requirement is not shown in the above equations, phosphorus,
in the amount of approximately one-sixth of the nitrogen requirement, was added to the
system. This system produced high rates of PCE degradation to ethene, up to 275
jimol/(L*day). Further microbiological studies are necessary to better understand this
system. Unlike the methanotrophic bacteria which help to degrade TCE, the bacteria and
the enzyme chemistry which contribute to the reductive dechlorination of PCE have yet
to be identified.
5.4 Combination of Anaerobic and Aerobic Processes
Anaerobic microorganisms
are effective in reducing highly chlorinated
compounds to less chlorinated compounds. However, as the number of chlorine atoms on
a compound decreases, reductive dechlorination reactions become more limiting, and
aerobic oxidation reactions become more favorable. Reductive dechlorination alone
would result in the accumulation of monochlorinated, dichlorinated, and other
hydrocarbon compounds.
The complementary capabilities of aerobic and anaerobic bacteria can be utilized
to effectively degrade PCE and TCE to harmless products. As demonstrated in Figure 57, a design of sequential anaerobic and aerobic biozones would allow the plume
contaminated with TCE and PCE to first travel through the anaerobic biozone, where the
PCE is degraded to less chlorinated compounds, followed by the aerobic zone, where the
products of the incomplete dechlorination and TCE are oxidized to CO2, H,O, and Cl'. In
order for cometabolism to occur, the proper growth substrates, nutrients, and electron
acceptors/donors must be present in each biozone.
PCE
TCE
PCE
ANAEROBIC BIOZONE
TCE
TCEAEROBIC BIOZONE
Other Less
Chlorinated
Compounds
CO,
H,O
Cl'
Figure 5-7 Ideal Schematic for Sequential Anaerobic/ Aerobic Degradation of PCE and TCE
6. DEVELOPMENT OF CONCEPTUAL DESIGN
6.1 Basis for Conceptual Design
Since bioremediation is still a new technology, there are very few standard
requisites for the design of a bioremediation system. Therefore the conceptual design for
the bioremediation of chlorinated solvents in the LF-1 plume will be constructed on the
basis of results from different laboratory and field experiments which also apply to the
conditions at LF-1. Once the conceptual design is completed, pilot tests based on the
design can be implemented, and the results of the pilot tests will help to develop a more
detailed bioremediation design.
6.2 Substrate Requirement
There have been many experiments performed to determine the substrate
concentration necessary for the degradation of contaminants. For the utilization of
methane as a primary growth substrate, one study determined that approximately 2 mg/L
of methane is required to treat 10 pjg/L of TCE, while 6.5 mg/L of methane is required to
degrade 100 gg/L of TCE. (Chang and Alvarez-Cohen, 1995) This estimation will be
used to specify the necessary injection concentration of methane at the wells. Since this
concentration range is safely below the solubility of methane in water (22 mg/L at 200 C),
the injection of methane solution is feasible for this design.
Methanol is a substrate that has been demonstrated to successfully biotransform
PCE with one of the highest reported reductive dechlorination rates. (DiStefano, 1991)
According to the stoichiometry of the microbial system (section 5.3), 4.3 moles of
methanol is required to degrade 1 mole of PCE completely to ethene. This molar
requirement takes into account the whole microbial system referred to in section 5.3. A
portion of the methanol requirement therefore corresponds to the methanol required by
the bacteria to form cell material (biomass). This estimation will be used to specify the
necessary injection concentration of methanol at the wells. Since methanol is completely
soluble in water at 20*C, the injection of methanol is feasible for this design.
6.3 Oxygen Requirement
A steady supply of oxygen is necessary to maintain the aerobic biozones in the
conceptual design. In bioremediation systems for petroleum hydrocarbons, first
approximations of oxygen requirements are typically based on a 3:1 weight ratio of
oxygen to organic carbon, or approximately a 1:1 molar ratio. (Kerr, 1994) The sources of
organic carbon include PCE, TCE, and the injected methane. Since TCE is present at
concentrations significantly lower than the injected methane (see Table 7-1 for the
injection concentrations of methane), the oxygen required to degrade TCE is negligible
compared to the amount of oxygen needed to degrade methane. As a result, methane is
considered to be the limiting organic carbon which will determine the oxygen
requirement in this design:
CH 4 +20 2
C02 + 2H 20
Even though the stoichiometry requires a 2:1 molar ratio of oxygen to methane, a 3:1
molar ratio of oxygen to organic carbon will be utilized in this conceptual design because
experience with bioremediation has shown that some of the oxygen can be consumed by
other reactions or is lost by inefficient distribution, which results in a required ratio that is
usually higher than the stoichiometric requirement. (Kerr, 1994)
Sources of oxygen that may be used include air, which is approximately 20%
oxygen, pure oxygen, which is industrially produced oxygen with a typical purity of 90%
or greater, and hydrogen peroxide, which is dissociated into oxygen and water. By
aerating water, a dissolved oxygen concentration of approximately 8 mg/L can be
achieved. Sparging pure oxygen into water can deliver approximately 40 mg/L of
dissolved oxygen. Hydrogen peroxide can provide as much as 47 mg/L of dissolved
oxygen. (National Research Council, 1993)
6.4 Bacteria
The conceptual design will assume that the concentration of bacteria is not a
limiting factor in the bioremediation. Since bacteria typically produce 10-20 pounds of
bacteria per 100 pounds of organic carbon consumed, it is acceptable to assume that the
source of bacteria for degradation will not be depleted as long as methane and methanol
are injected into the plume. (Nyer, 1992)
6.5 Nutrient Requirements
For the aerobic biozones, nutrient requirements are calculated on the basis of all
the methane being converted to cell material, which is approximated by a weight ratio of
carbon to nitrogen to phosphorus of 100:10:1. (Kerr, 1994) This is typically a
conservatively high estimate for the nutrient requirements since some of the methane
might be directly converted to carbon dioxide and water.
For the anaerobic biozones, nutrient requirements will be calculated with the
stoichiometry provided in the microbial system (Section 5.3). The weight ratio of
methanol carbon to nitrogen to phosphorus is 1046:6:1. It is important to note that these
nutrient requirements are specific to the microbial system discussed in Section 5.3, and
might not be applicable to other anaerobic systems, especially since the type of
microorganism(s) involved in these reactions are unknown.
6.6 AnalyticalModels
Analytical equations were used to develop the design for the injection wells and
determine the total time of bioremediation. It was decided that analytical equations are
sufficient to create a preliminary, conceptual bioremediation design, which is the aim of
this project.
6.6.1 Injection Wells
Analytical equations derived by Welty and Gelhar (1994) quantify the behavior of
a solute which is injected at a recharge well. Although the intent of these diverging flow
equations was to evaluate longitudinal dispersivity from tracer tests, they are also useful
in determining other unknown parameters, given a known longitudinal dispersivity. The
equation assumes that the injected solute is conservative, and that the dispersivity, aquifer
thickness, and injection rate are all constant. It also assumes that there is radial flow away
from the well. The equation for solute concentration in diverging flow is expressed as:
S- erfc
,
(6-1)
r2
where
= CR / Ciet ,
CR = the concentration of the injected solute at a radial distance R from the
injection well,
Cm,• = the injection concentration at the well,
t=t/tm,
t = time,
tm= R2 / (2*A),
A= Q / (2*x*rl*b),
Q = injection flowrate,
l = aquifer porosity ,
b = aquifer thickness,
c = longitudinal dispersivity of aquifer.
This equation will give the relationship between the desired radius for a biozone, R, the
time it will take for that biozone to be established, t, the injection rate needed to establish
and maintain that biozone, Q, and the injection concentration required (Ci.j)
to attain a
minimum concentration at the edge of the biozone, CR. The spreadsheet calculations of
these variables are in Appendix C and the results of these calculations are in Table 7-2.
The aim of this conceptual design will be to remediate the highest levels of
contamination in the PCE and TCE plumes. The input parameters are R, CR, and t, the
desired time for the system to reach steady state. As Figure 6-1 shows, the distance R
coincides with the maximum local concentration of contaminant.
Direction of Groundwater Flow
x: injection point
0: high local contaminant concentration
R,: Radius of influence of well 1
R,: Radius of influence of well 2
Figure 6-1 Injection Well Schematic using Parameters in Welty-Geihar Solution
The variable CR will be determined by the requirements for remediating the area of high
local contaminant concentration indicated by the dot in Figure 6-1. These requirements
could include supplemental levels of substrate, oxygen, and/or nutrients, depending on
the conditions of that location. Once R is given and the dispersivity is known, the value
for tFat which steady state is reached can be determined by using the breakthrough curves
shown in Figure 6-2, which were developed by Welty and Gelhar.
0.8
0.6
A
C
0.4
0.2
0
0
1
2
3
4
Figure 6-2 Dimensionless Breakthrough Curve for Continuous Injection and Constant Dispersivity
(Welty and Gelhar, 1994)
The estimation of t can then be used to calculate C, which will provide the concentration
needed to be injected at the recharge well to achieve a concentration of CR at a radial
distance R from the well. The desired time to reach steady state can then be introduced,
and the necessary injection flow rate is calculated from the expression for L. Once the
radii of the biozones are determined, the well placement can be designed in a way that the
radii of influence do not overlap, thereby allowing the formation of distinct anaerobic and
aerobic biozones.
6.6.2 Biodegradation
Estimates for the biodegradation rates of TCE and PCE will be used to determine
the total time necessary to biodegrade the contaminants to 5 jig/L, the MCL for both
compounds. The cometabolic biodegradation of TCE and PCE will be modeled using
both zeroth order and first order kinetic expressions. Zeroth order and first order
estimates of biodegradation will provide lower and upper bounds, respectively, for the
total bioremediation time, which is sufficient for the purposes of a conceptual design.
Table 6-1 shows the degradation rate estimates found in the literature. The zeroth order
estimates are based on laboratory experiments and the first order estimates are based on
field experiments in groundwater. These rate estimates are uncertain given the conditions
surrounding the experimentation, however, due to the lack of rate estimates in the
literature, they will be used in this design as a first approximation for degradation.
Table 6-1 Degradation Rate Estimates for PCE and TCE
A: DeBruip
ward, 1991
The zeroth and first order reaction rate expressions for the degradation of PCE and TCE
are:
C = Co-(ko. to), and
(6-2)
C = Co* exp(- ki* ti),
(6-3)
where Co = the initial concentration of the contaminant,
C = the final concentration of the contaminant,
ko = the zeroth order rate constant from Table 6-1,
k, = the first order rate constant from Table 6-1,
to = the time it takes for the contaminant to degrade to C in a zeroth order reaction,
and
t, = the time it takes for the contaminant to degrade to C in a first order reaction.
These equations will be applied at every injection well in the conceptual design. Since
every injection well has a radius of influence which coincides with the highest local
contaminant concentration, the biodegradation equations will estimate the time to
remediate the contaminant at this concentration. Therefore the conceptual design will be
constructed such that the final concentration of TCE and PCE will be the desired remedial
level, which is 5 glg/L (the MCL value), and the initial contaminant concentration will
vary depending on the conditions surrounding the specific injection well.
7. CONCEPTUAL DESIGN
The purpose of this bioremediation system is to remediate the highest
concentrations of TCE and PCE in the LF-1 plume to their respective MCL values.
Therefore, the design will focus on utilizing injection wells to create aerobic and
anaerobic biozones which contact the maximum contaminant concentration at the well's
radius of influence, to ensure that mixing between the injected bioenhancers and the
contaminant due to dispersion and diffusion will occur.
7.1 Placement of Injection Wells
As Figure 7-1 shows, there are fourteen recommended injection points, half of
which utilize existing well locations. There will be four alternating aerobic/ anaerobic
biozones, followed by two final aerobic biozones. The four aerobic biozones will be
created by injections at: wells 1 and 4 (Aerobic Biozone 1), wells 5 and 6 (Aerobic
Biozone 2), wells 10, 11, and 12 (Aerobic Biozone 3), and at wells 13 and 14 (Aerobic
Biozone 4). The two anaerobic biozones will be created by injections at: wells 2 and 3
(Anaerobic Biozone 1), and wells 7, 8, and 9 (Anaerobic Biozone 2).
3W000L
"U.
"INJECTIONwELL
9
' Aerobic Biozone
Q
Anaerobic Biozone
32000SJI3IIO1
(S
20000
2MC00,
7
2,e0000
24000
100O !00
Well
Well
Well
Well
1: MW701A
2: MW22
3: MW23
4: Near MW48
00009C00100
0 7ROOM
Well 5: Near Edmunds Pond
Well 6: Near WT23
Well 7: MW43
Well 8: Near MW36B
oGoi?000130)
I00s S000Ifl0GW700'Ji560~90Q0
TEET1
Well 9: WT26
Well 13: MW52
Well 10: MW44
Well 14: Near MW5
Well 11: Near MW45
Well 12: Near MW40
Figure 7-1 Injection Well Placement
The injection wells are placed with the purpose of straddling the target of
remediation, with equivalent but counteractive velocities acting on the point of high
concentration, as Figure 7-2 illustrates. This will in turn form a radially stagnant zone,
where the contaminant-containing groundwater will be restricted from moving laterally,
but it will continue to move downgradient, thereby ensuring movement of the plume
through the biozones. The biozones have been configured so that the radius of influence
of each injection well is undisturbed by the surrounding injection wells, so that each
biozone is well-defined. It is expected that the high concentration points of the
contaminant plumes will travel through the alternating aerobic/ anaerobic biozones and
undergo bioremediation, with a final aerobic biozone established to prevent any high
levels of contamination from bypassing treatment and reaching the bay. Since there is a
regional gradient, it is possible that the injected contents will also travel downstream,
however it is assumed that mixing between the contaminants and the injected contents,
which leads to bioremediation, will occur.
Anaerobic
* High Local
Concentration
Biozone
.---.
Velocity Induced by
Injection Well
Aerobic
Biozone
x Injection Well
Figure 7-2 Conceptual Design of Injection Wells
7.2 InjectionParameters
7.2.1 Injection Contents
The contents for injection will vary from well to well. The regulatory issues
involved with the injection of the different substances will not be addressed in this
conceptual design. At injection points where aerobic conditions need to be induced or
maintained, water sparged with pure oxygen will be provided for the oxygen supply.
Even though the majority of the plume is fairly aerobic, the dissolved oxygen
concentrations are inadequate for the mineralization of the methane which is injected into
the aerobic biozones. While the background oxygen concentration in the plume ranges
between 0-10 mg/L (Figure 4-3, Appendix A), the total necessary oxygen concentration
varies from 4-40 mg/L. Since high concentrations of dissolved oxygen are required, as
shown in Table 7-1, the injection of pure oxygenated water is necessary. In addition, a
primary growth substrate and nutrients will be added to stimulate the bacteria to high
levels of cell production. For the anaerobic biozones, a primary growth substrate and
nutrients will still be added, but the oxygen will no longer be injected and the heightened
bacterial population will exert a higher BOD (biochemical oxygen demand), thereby
creating anaerobic conditions.
The site characterization determined that most of the plume had sufficient levels
of nitrogen, however several places with adequate levels were nearby to place(s) which
were depleted of nitrogen. This design assumes that nitrogen will reach these places by
transport, so that additional nitrogen will not be injected. There is also the assumption
that the entire plume contains no phosphorus, so that it will be added at all injection
points.
The injected contents for this conceptual design were determined from the
literature sources that demonstrated the most successful results. For the aerobic biozones,
the recommended primary substrate is methane (in dissolved form). (Semprini and
McCarty, 1991b) For the anaerobic biozones, the recommended primary substrate is
methanol, which has the highest demonstrated PCE degradation rate in the literature.
(DiStefano et al, 1991) The recommended nutrients for all the biozones are ammonium
(NH4+) and phosphate (P0 4"). (Nyer, 1992) This conceptual design does not address
potential regulatory issues involved with the injection of the different substances.
7.2.2 Injection Flowrates and Concentrations
The recommended flowrates and concentrations for methane, methanol,
ammonium, phosphate, and oxygen are summarized in Table 7-1. The concentrations
were calculated on the basis of the requirements addressed in sections 6.2- 6.5, and the
flowrates were calculated on the basis of the analytical equation described in section
6.6.1.
For the aerobic biozones, the relationship between the substrate (methane)
concentration and TCE concentration is assumed to be linear and calculated with the
following information: 2 mg/L methane is necessary to degrade 10 jLg/L TCE and 6.5
mg/L methane is required for 100 gg/L TCE. (Section 6.2) The linear relationship based
on these two data points is:
C.,h,,.e = (50* CTcE)+ 1500
(7-1)
where Cm,., = the required concentration of methane, and
CTCE = the concentration of TCE.
The oxygen requirement in the aerobic biozones was calculated by utilizing the 3:1 molar
ratio of oxygen to organic carbon (Section 6.3):
Ca.n = Cme,,*
(
MWan * 3 mol oxygen
1 mol methane
MW.mehnme
where Co.g. = the required concentration of oxygen,
MWm,t. , = the molecular weight of methane, and
MWoxys . = the molecular weight of oxygen.
The nitrogen and phosphorus requirements in the aerobic biozone are expressed by the
100:10:1 weight ratio of organic carbon to nitrogen to phosphorus (Section 6.5), or:
Cmethane
Cniro.gen = C(7-3)
10
Cmehsane
Cphosphorus = Cmed
100
(7-4)
Once Cg,, and Cphosphor w are calculated, the necessary ammonium (NH4') and phosphate
(P0 4-3) concentrations can be determined:
Cammonium = Cnitogen * M)
MWnitro.en
(7-5)
Cphosphate = Cphosphorus * MWphsphat
-MWWphospho
(7-6)
(7-6)
where C.moni. = the required concentration of ammonium,
Cphosphae = the required concentration of phosphate,
MWmo. = the molecular weight of ammonium,
MW.gosn,= the molecular weight of nitrogen,
MWpho.h = the molecular weight of phosphate, and
MWpho.phom, = the molecular weight of phosphorus.
For the anaerobic biozones, the substrate (methanol) requirement is calculated
using the stoichiometric relationship described in Section 6.2, which states that 4.3 moles
of methanol are needed to completely reduce 1 mole of PCE to ethene:
C.,,ano = CPCE*
= -MWmeMha•
MWPCE
*
( 43 mol methanol)
I(7-7)
1 mol PCE
= the required concentration of methanol,
CPCE = the concentration of PCE,
MW, = the molecular weight of PCE, and
MW.mc.., = the molecular weight of methanol.
where Cm,~e,
The nutrient requirements are expressed by the 1046:6:1 weight ratio of organic carbon to
nitrogen to phosphorus (Section 6.5), or:
Cnir,•en = C.hao*
6gN
6g
1046g C
lg P
1046gg C'
Cphosphonr = Cmethanol* 1
(7-8)
(7-9)
Once CGgin and Cphosphor,,
are calculated, the necessary ammonium (NH4) and phosphate
(P04-') concentrations can be determined using equations 7-5 and 7-6.
The calculated concentration values are then corrected for the initial
concentrations which may be present. This conceptual design assumes that the
"background" concentration is constant. Since the transport equation is linear with respect
to concentrations, the required concentration is equal to the difference between the
calculated concentration (from Equations 7-1 through 7-9) and the background
concentration. Since all of the calculations in Equations 7-1 through 7-9 correspond to the
required concentrations at the injection well's radius of influence (highest local
contaminant concentration), it is important to calculate the injected concentrations which
are necessary to achieve the concentrations at the radius of influence. Once C is
determined from Equation 6-1,
S erfc
,
(6-1)
the necessary injection concentration can be calculated:
Cinject -
Ccalculated
C
where Cj,, = the necessary injected concentration and
Ccaculat.d = the concentration calculated from Equations 7-1 through 7-9.
(7-10)
As described in Section 6.4.6.1, C is dependent on
?, which is dependent on the
desired time to reach steady state, the desired radius of influence, the porosity of the
medium, the aquifer thickness, and the injection flowrate. The required injection flow rate
was calculated using Equation 6-1. Recalling that A = Q / (2*n*l*b), tm = R2 / (2*A), and
t = t / t., these expressions are utilized to obtain an expression for flowrate:
r* qr*b* R2 * t
Q=
t
,
(7-11)
where Q = injection flow rate,
q = average aquifer porosity = 0.39 (Alden et al, 1996),
b = average aquifer thickness = 113 ft (Stone & Webster, 1996),
R = radius of influence of injection well, and
t = the time to reach steady state.
The variable t represents the time that it will take for the concentration of the solute at the
radius of influence to reach the desired concentration. Therefore the flowrate will change
depending on the value of t. The more time that is designated for the system to reach
steady state, the smaller the flow rate that is required. As Table 7-1 shows, this design
utilizes a t value of five years because it resulted in velocities at the radius of influence
which were on the same order of magnitude as the regional groundwater velocity. (See
Appendix C) This ensures that the disturbance to the regional flow is minimized.
Table 7-1 Summary of Injection Contents, Concentrations, and Flowrates
Well
Number
Contaminant
Concentration
(g/L)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
Injected
Substrate
(Ig/L)
Injected
Oxygen
(mg/L)
Injected
Ammonium
(Ig/L)
Injected
Phosphate
(og/L)
64
4869.21
29.22
293.04
149.22
(years)
5
17069
65
65
64
10
10
30
30
48
26
26
10
0
0
57.58
56.75
4897.31
2072.01
2072.01
25.86
25.86
41.21
2900.81
2949.26
2090.82
1554.00
1562.97
0
0
23.67
12.43
12.43
0
0
0
17.40
9.57
4.35
9.32
9.38
0*
0*
294.73
0
266.40
0
0
0.30
0
0*
0
0
0
0.17
0.17
150.08
63.50
63.50
0.08
0.08
0.12
88.90
90.38
64.07
47.62
47.90
5
5
5
5
5
5
5
5
5
5
5
5
5
4916
8011
11835
17069
17069
13769
13769
22531
17069
8011
9955
17069
11835
S.
Time to
Reach
Steady
State
Injection
Flowrate
(ft/ hr)
Bold: PCE concentration, Plain: TCE concentration, *: Surrounding well(s) show very low nitrate levels.
7.3 Estimation of Bioremediation Time
The total time for bioremediation of TCE and PCE to 5 gg/L must incorporate the
time it takes for a biozone to reach steady state (i.e. the concentration of the injected
bioenhancer at the radius of influence reaches the maximum intended concentration) and
the actual time of biodegradation of the contaminants. Therefore equations 6-2 and 6-3
are amended to include the time needed to establish the biozone:
C= Co - [ko*(to-tb)], and
(7-12)
C = Co *exp[- ki* (ti-tb)],
(7-13)
where C = the ultimate contaminant concentration = 5 Jtg/L,
Co= the initial contaminant concentration,
tb = the time needed to establish the biozone,
to = the total time to bioremediate the contaminant to 5 jtg/L if it is a zeroth order
reaction, and
t, = the total time to bioremediate the contaminant to 5 jtg/L if it is a first order
reaction.
Note that tb is subtracted from the total time of bioremediation because the extra time
needed for the biozone to reach steady state results in a larger value for the total
bioremediation time. (See Appendix B)
The total bioremediation time will vary depending on the desired time for the
system to reach steady state. For this conceptual design, if the system reached steady state
in five years, the total time for bioremediation (which includes the time to reach steady
state and the time of biodegradation) would be in the range of five to fourteen years, as
summarized in Table 7-2.
Table 7-2 Summary of Bioremediation Time Estimates
Well R (ft) a / R
Number
C.,,,, Time to Q Total Oth order
(glg/L) Reach (ft/hr) bioremediation
Steady
time (yrs)
State: t
Total Ist order
bioremediation
time (yrs)
(yrs)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
1500
720
960
1200
1500
1500
1320
1320
1800
1500
960
1080
1500
1200
0.06
0.125
0.094
0.075
0.06
0.06
0.068
0.068
0.05
0.06
0.094
0.083
0.06
0.075
2.4
3
2.8
2.6
2.4
2.4
2.5
2.5
2.2
2.4
2.8
2.7
2.4
2.6
0.9652
0.9357
0.9494
0.9597
0.9652
0.9652
0.9616
0.9616
0.9656
0.9652
0.9494
0.9566
0.9652
0.9597
64
65
65
64
10
10
30
30
48
26
26
10
0
0
5
5
5
5
5
5
5
5
5
5
5
5
5
5
17069
4916
8011
11835
17069
17069
13769
13769
22531
17069
8011
9955
17069
11835
Bold: PCE concentration, Plain: TCE concentration
5.00
5.00
5.00
5.00
5.00
5.00
5.00
5.00
5.00
5.00
5.00
5.00
n/a
n/a
7.72
13.87
13.87
7.72
5.74
5.74
11.20
11.20
12.82
6.76
6.76
5.74
n/a
n/a
8. CONCLUSION
8.1 Summary of Conceptual Design
The basic components of bioremediation are the electron acceptor, electron donor,
nutrients, and microorganisms. These components, along with other environmental
conditions such as proper pH and temperature, are necessary for the successful
bioremediation of TCE and PCE in the LF-1 plume. The conceptual design relies on the
establishment of sequential anaerobic and aerobic biozones to degrade the high local PCE
and TCE concentrations. Each biozone consists of the essential components required for
bioremediation, as illustrated in Figure 8-1.
ANAEROBIC
Electron Acceptor: PCE
Electron Donor: Methanol
Nutrients: Ammonium, Phosphatc
AEROBIC
Electron Acceptor: Oxygen
Electron Donor: TCE
Nutrients: Ammonium, Phosphate
Directionof ContaminantPlume Movement
Figure 8-1 Bioremediation with Sequential Anaerobic/ Aerobic Biozones
In order to reduce the TCE and PCE concentrations at the areas of highest
measured concentration to 5 jtg/L by complete mineralization to carbon dioxide, water,
and chloride, the following parameters of the conceptual design must be implemented.
The required injection rates, which range from 4,916- 22,531 ft3/hr, should be examined
when assessing the cost-effectiveness of this design. While most of the plume contains a
sufficient background level of nitrogen, some spots require the injection of 0.30- 295
gg/L of additional ammonium. The phosphate requirement for the areas of highest
measured TCE and PCE concentration ranges from 0.08- 150 pg/L. The substrate for the
anaerobic biozones, methanol, will be injected at concentrations ranging from 25-58
jtg/L. The substrate for the aerobic biozones requires higher concentrations, with methane
concentrations ranging from 1550-4900 gg/L. There is no oxygen injected at the
anaerobic biozones, but the aerobic biozones require 4-30 mg/L of additional dissolved
oxygen. The total time for bioremediation will range between 5 and 14 years, depending
on the conditions at the specific spot in the plume.
8.2 PotentialProblems
8.2.1 Clogging
The stimulation of bacteria is an integral part of the effective bioremediation of
chlorinated solvents. The bacteria population is stimulated through the addition of
necessary nutrients, substrate, electron donors, and electron acceptors. The resulting
enlarged bacterial population can often have the counterproductive effect of clogging the
aquifer, thereby reducing the hydraulic conductivity and porosity, which can then affect
the flow of groundwater used to deliver the essential supplements to the bacteria in the
contaminated region of the aquifer. Clogging may also occur due to inorganic reactions,
such as the precipitation of metals. (Nyer, 1992)
8.2.2 Intermediate Toxicity
When an intermediate product of the biodegradation process exerts toxic effects
on bacterial cells, it can significantly affect the rate of biodegradation of PCE and TCE.
For example, the TCE epoxide has been shown to react with cell protein. (Hinchee et al,
1995a) As the amount of the chlorinated compound degraded increases, the bacterial cell
activity declines until the cell becomes completely inactive; this degraded amount per
amount of cells inactivated has been termed the transformation capacity (Tj).
Intermediate toxicity poses serious limitations in biodegradation with methane-utilizing
bacteria. It has been demonstrated that TCE concentrations of 0.1 mg/L or greater are
necessary to induce the toxicity produced by intermediate products. (Chang and AlvarezCohen, 1995) Since concentrations at LF-1 are significantly less than this value,
intermediate toxicity is not likely to be a problem.
8.2.3 Competitive Inhibition
Since chlorinated compounds and primary growth substrates are degraded by the
same enzyme in cometabolic degradation, competition can occur between them for the
enzyme's active sites. As a result, the degradation rates for both the growth and
cometabolic substrates can be reduced. At the LF-1 plume, for example, where TCE is
present at relatively low concentrations, the methane can more effectively compete for the
active sites, thereby lowering the degradation rate of TCE. One set of experiments found
that the optimal TCE degradation rate would occur when the methane concentration was
between 1.2 and 2.4 mg/L, however this corresponded to a TCE concentration of 7.95
mg/L, which is significantly higher than the TCE concentrations at LF-1. (Chang and
Alvarez- Cohen, 1995) Therefore it can be inferred that this conceptual design will need
to be modified to account for inhibition effects, due to the high substrate levels calculated
in section 7.2.2.
8.3 Recommendations for Future Work
Given that the purpose of this thesis was to develop a conceptual design for
bioremediation, there are many ways on which the design can be improved to make the
process more cost-effective and efficient. These improvements, which were beyond the
scope of this thesis, include the following:
* Use of horizontal wells instead of vertical wells will enhance the distribution of the
injected contents. (Lindsey, 1997)
* Gas phase injection instead of aqueous phase injection will result in minimal
displacement of groundwater and better mixing.
* Injection of bioenhancers in alternating pulses, instead of continuous injection, will
ensure that high concentrations of the growth-stimulating materials do not accumulate
around the injection well.
* Use of hydrogen peroxide as the oxygen source, instead of oxygenated water, will
help to prevent clogging because of its strong disinfectant characteristics. (National
Research Council, 1993)
* Use of phenol as a primary growth substrate in aerobic conditions, instead of
methane, may result in higher TCE degradation rates. Although the injection of
phenol to the groundwater may raise some regulatory issues, there are studies which
have shown that phenol is more effective than methane in the cometabolic
degradation of TCE. Furthermore, the phenol-utilizing bacteria have not shown any
intermediate toxicity effects in experiments, whereas intermediate toxicity effects on
methane-oxidizing bacteria have been reported. (Hinchee et al, 1995a) Phenol also
has a higher solubility in water and, unlike methane, has no explosive properties.
* Methanol may be able to serve as the primary growth substrate for both aerobic and
anaerobic degradation, which would simplify the treatment process, and probably
reduce the total bioremediation cost. The ability of the aerobic bacteria to obtain
energy from methanol (a methane oxidation intermediate) indicates that it might serve
as a substitute for methane to drive the cometabolism of TCE, as discussed in section
5.2.
* Use of detailed numerical groundwater modeling to refine design parameters. (Wagle,
1997)
If the aforementioned enhancements were incorporated into this conceptual design, insitu bioremediation would be a more suitable and attractive remediation technology for
the achievement of a cost-effective, thorough, and efficient solution to the contamination
at LF-1.
8.4 Summary
Chlorinated compounds represent the most prevalent organic groundwater
contaminants in the country. (Kerr, 1994) Until recently, bioremediation had not been
considered a viable alternative for the remediation of chlorinated solvents. However,
when degradation products of the chlorinated contaminants started to be found in the
groundwater, an intense effort to understand the responsible processes began. As a result,
there is now a wealth of theoretical and experimental information suggesting that
bioremediation can be utilized to effectively degrade chlorinated compounds. However,
the lack of full-scale implementation to date leaves many questions to be answered,
particularly regarding the cost-effectiveness of the process. Thus, there is much yet to be
learned about this new, but promising, remediation technology.
9. REFERENCES
ABB Environmental Services, Inc., "Record of Decision, Interim Remediation, Main
Base Landfill (AOC LF-1) Source Operable Unit," Installation Restoration
Program, Massachusetts Military Reservation, Cape Cod, MA, January 1993.
Alden, Dan, Amarasekera, Kishan, Collins, Michael, Elias, Karl, Hines, Jim, Jordan,
Benjamin R., Lee, Robert F., An Investigation of Environmental Impacts of the
Main Base Landfill Groundwater Plume, Massachusetts Military Reservation,
Cape Cod, MA, Master of Engineering Group Thesis, Department of Civil and
Environmental Engineering, Massachusetts Institute of Technology, Cambridge,
MA, 1996.
Anderson, James E., McCarty, Perry L., "Model for Treatment of Trichloroethylene by
Methanotrophic Biofilms," JournalofEnvironmental Engineering,120(2), 379400, 1994.
Bedient, Philip B., Rifai, Hanadi S., Newell, Charles J., Ground Water Contamination:
Transport and Remediation, PTR Prentice Hall, Englewood Cliffs, NJ, 1994.
Cape Cod Commission, http://www.vsa.cape.com/-cccom/trend.htm, 1996.
CDM Federal Programs Corporation, "Remedial Investigation Report: Main Base
Landfill and Hydrogeological Region I Study," Boston, MA, April 1995.
Chang, Hsiao-Lung, Alvarez-Cohen, Lisa, "Model for the Cometabolic Biodegradation of
Chlorinated Organics," EnvironmentalScience and Technology, 29(9), 23572367, 1995.
DeBruin, Wil P., Kotterman, Michiel J.J., Posthumus, Maarten A., Schraa, Gosse,
Zehnder, Alexander J.B., "Complete Biological Reductive Transformation of
Tetrachloroethene to Ethane," Applied andEnvironmentalMicrobiology, 58(6),
1996-2000, 1992.
DiStefano, Thomas D., Gossett, James M., Zinder, Stephen H., "Reductive
Dechlorination of High Concentrations of Tetrachloroethene to Ethene by an
Anaerobic Enrichment Culture in the Absence of Methanogenesis," Applied and
EnvironmentalMicrobiology, 57(8), 2287-2292, 1991.
Gorelick, Steven M., Freeze, R. Allan, Donohue, David, Keely, Joseph F., Groundwater
Contamination: Optimal Capture and Containment, Lewis Publishers, Boca
Raton, FL, 1993.
Gupta, S.K., Djafari, S.H., Zhang, J., "Oxygen Transport in an In-Situ Bioremediation
Application," Innovative Technologies for Site Remediation, Proceedings of the
National Conference, American Society of Civil Engineers, New York, NY, 165172, 1995.
Hazen, Terry C., Lombard, K.H., Looney, B.B., Fliermans, C.B., Eddy-Dilek, C.A., "In
Situ Bioremediation of Chlorinated Solvent with Natural Gas," Savannah River
Technology Center, http://www.srs.gov/general/sci-tech/expertise/bioreml.html.
HAZWRAP, "Installation Restoration Program, Phase I - Records Search, ed. 2," Otis
Air National Guard Base, Massachusetts, 1987.
Hinchee, Robert E., Leeson, Andrea, Semprini, Lewis, Ong, Say Kee, eds.,
Bioremediation of Chlorinated and Polycyclic Aromatic Hydrocarbon
Compounds, Lewis Publishers, Boca Raton, FL, 1994.
Hinchee, Robert E., Leeson, Andrea, Semprini, Lewis, eds., Bioremediation of
Chlorinated Solvents, Battelle Press, Columbus, OH, 1995a.
Hinchee, Robert E., Wilson, John T., Downey, Douglas C., eds., Intrinsic
Bioremediation, Battelle Press, Columbus, OH, 1995b.
Howard, Philip, ed., Handbook of Environmental Degradation Rates, Lewis Publishers,
Chelsea, MI, 1991.
Kerr, Robert S., ed., Handbook of Bioremediation, Lewis Publishers, Boca Raton, FL,
1994.
Kobus, Helmut, Barczewski, Baldur, Koschitzky, Hans-Peter, eds., Groundwater and
Subsurface Remediation: Research Strategies for In-situ Technologies, Springer,
Berlin, 1996.
Kostek, Rebecca, "Identification of a Potential Contaminant Source to the Main Base
Landfill Plume at the Massachusetts Military Reservation," Master of Engineering
Thesis, Department of Civil and Environmental Engineering, Massachusetts
Institute of Technology, Cambridge, MA, 1997.
Leon, Roberto, "Post-Closure Management of a Hazardous Waste Landfill at the
Massachusetts Military Reservation Main Base Landfill," Master of Engineering
Thesis, Department of Civil and Environmental Engineering, Massachusetts
Institute of Technology, Cambridge, MA, 1997.
Levin, Morris A., Gealt, Michael A., eds., Biotreatment of Industrial and Hazardous
Waste, McGraw-Hill, New York, NY, 1993.
Lindsey, Mia, "The Use of Horizontal Wells for Environmental Remediation for the
Landfill-i Plume at the Massachusetts Military Reservation in Cape Cod, MA,"
Master of Engineering Thesis, Department of Civil and Environmental
Engineering, Massachusetts Institute of Technology, Cambridge, MA, 1997.
Massachusetts Department of Environmental Protection, http://www.magnet.state.ma.us/
dep/sero/mmr/mmr.htm, 1996.
Masterson, John P., Barlow, Paul M., "Effects of Simulated Ground-Water Pumping and
Recharge on Ground-Water Flow in Cape Cod, Martha's Vineyard, and Nantucket
Island Basins, Massachusetts," Open-File Report 94-316, U.S. Geological Survey,
Marlborough, MA, 1994.
Masterson, John P., Stone, Byron D., Walter, Donald A., Savoie, Jennifer,
"Hydrogeologic Framework of Western Cape Cod, Massachusetts," Open-File
Report 96-46, U.S. Geological Survey, 1996.
Metcalf & Eddy, Inc., "Installation Restoration Program, Phase I - Records Search," Otis
Air National Guard Base, Massachusetts, January 1983.
National Research Council, In Situ Bioremediation: When Does it Work?, National
Academy Press, Washington, D.C., 1993.
Nyer, Evan K., Groundwater Treatment Technology, Van Nostrand Reinhold, New York,
NY, 1992.
O'Brien and Gere Engineers, Inc., Innovative Engineering Technologies for Hazardous
Waste Remediation, Van Nostrand Reinhold, New York, NY, 1995.
OPTECH (Operational Technologies Corporation), "Plume Containment Design Data
Gap Field Work Technical Memorandum, MMR, Cape Cod, MA," San Antonio,
TX, 1996a.
OPTECH (Operational Technologies Corporation), LF-1 60% Work Design Data, Cape
Cod, MA, 1996b.
Semprini, Lewis, Hopkins, Gary D., Roberts, Paul V., Grbic- Galic, Dunja, McCarty,
Perry L., "A Field Evaluation of In-Situ Biodegradation of Chlorinated Ethenes:
Part 3. Studies of Competitive Inhibition," Ground Water, 29(2), 239-250, 1991a.
Semprini, Lewis, McCarty, Perry L., "Comparison between Model Simulations and Field
Results for In-Situ Biorestoration of Chlorinated Aliphatics: Part 1.
Biostimulation of Methanotrophic Bacteria," Ground Water, 29(3), 365-374,
1991b.
Semprini, Lewis, McCarty, Perry L., "Comparison between Model Simulations and Field
Results for In-Situ Biorestoration of Chlorinated Aliphatics: Part 2. Cometabolic
Transformations," Ground Water, 30(1), 37-43, 1992.
Skiadas, Panagiotis, "Design of an In Situ Bioremediation Scheme of Chlorinated
Solvents by Reductive Dehalogenation Sequenced by Cometabolic Oxidation,"
Master of Engineering Thesis, Department of Civil and Environmental
Engineering, Massachusetts Institute of Technology, Cambridge, MA, 1996.
Skipper, H.D., Turco, R.F., eds., Bioremediation: Science and Applications, Soil Science
Society of America, Madison, WI, 1995.
Stone and Webster Engineering Corporation, "Massachusetts Military Reservation, Data
Gap Supplemental Remedial Investigation Draft Report, Area of Concern: LF- 1
NWOU," December 1996.
University of Minnesota Biocatalysis/ Biodegradation Database, http://dragon.labmed.
umn.edu/-~ynda/tce/reac/tce_mechAl.gif, 1997.
Wagle, Mandeera, "A Simulation of Pumping Schemes for the Containment of the
Groundwater Contaminant Plume under the Main Base Landfill on the
Massachusetts Military Reservation in Cape Cod, MA," Master of Engineering
Thesis, Department of Civil and Environmental Engineering, Massachusetts
Institute of Technology, Cambridge, MA, 1997.
Welty, Claire, Gelhar, Lynn, "Evaluation of Longitudinal Dispersivity from Nonuniform
Flow Tracer Tests," Journalof Hydrology, 153, 71-102, 1994.
10. APPENDICES
Appendix A: Dissolved Oxygen Concentration Data for LF-1 (OPTECH, 1996b)
*m·r3\··l
~~. · · · rvr~vvv~rvv
IU-JUI-o3|,IIlY
27MWX2A3XXA9XX
X
72OMWX20XX95X
13-Jul-95
13-Jul-95
I3-Jul-95
L
27MWXs4XXX952X·-~----
Z7MWX5OXXA9SX)1I
27MWS67XXA9SXX
27MWXS4XXX9S2X
71.331
LF•
LF-I
LF-1
LF-I
27MWX45XXX95XX
27MW103XXA95XX
27MW103XXZ95XX
27PSXX2XXX95XX
LF-I 271PSXXSXXX95XX
--
LF-I
LF-I
27MWX47XXX95XX
27MWX26XXA95XX
LF-I
27MWX4IXXX95XX
LF-I
27MWX35XXX95XX
LIF-1
27MWX38XXZ94XX
LF-I
LF-I
27MWX3SXXA9SXX
27MWX52XXX95XX
LF-I
I.E-T
I.E-I
27MWX46XXA95XX
27MWX3 IXXA95XX
27MWXS3XXX953X
LF-I
LF-I
27MWX39XXZ9SXX
LF-I
LF-I
I-F,-I
ICF-i
IF-I
IF-I
IF-I
X'
27MWX39XXA952X
27MWX40XXX952
LF-I
27MW567XX119527
27MW567XXX9523
27MWX-ISXXX9S2.
LF-I
2tiiDX2X
9>
114qU
1136
0817
~~""~""-~`
'~~
WxTiiBbr>Ex
ifiT
LF-I
.
19-Jul-95
x"`~~~"""^~~^^xI~x~'~'-
27MW IO3XXZ9S2X
2i7iWX26XXA952X
27MW103XXA952X
27MWX26XXB952X
27MWX53XXX952X
27MWX50XXA952X
27MWX47XXX952 X
27PSXX5XXA9SXX
X
?7MWX- 7XXA952,
020 11006
1045
1029 NA
1123
112I
ILNA
gIqj4
[NA
1009
INA
1032
NA
jAA
I1IIU
NA
NA
NA
INA
1349
1336
11455
INA
INA
11520
INA
INA
NA
NA
-NA
1450
11320
INA
11322
10802
836
10748
0824
INA
NA
0915
0908
NA
10751 INA
0827
NA
0911
NA
11042
11448
INA
INA
ýA
-- ~--1NA
NA
J
1NA
11326
NA
NA
A
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
4-27
9,"76
6.19
0757
1047
1254
1124
1538
NA
NA
5.10
9i95
6.65
0800
1050
1257
1127
1542
NA
NA
5.14
10.05
5.58
0851
NA
I
INA
0754 INA
0830 NA
0914NA
f
NA
NA
NA
NA
NA
NA
NA
NA-
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
151.91
111.77
120.35
T49.41
141.87
139.37
162.44
141.81
138.11
59.18
144.31
140.61
109.27
117.85
162.35 159.85
293.70
291.20
------ L--- ""-· - -· - ---
21-Sep-95
--f---
liiW
mr28
1625
i1i--
0958 10421033700
0912 0952 0936 650
1036 _17.48
094-0 7.06
1458
1739
1734
I 39
L.91
il1S
1.96
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
fix'~
-
NA
10,46
..
11025 3.51
1430
1517 ·2.52
·
I
I
1
------ · c------·
i-
1345 7.72
t-.-?-_~=-?-~t---~~·~-·---t----
-24
5liS
1159
0910
7.48
7.86
0915
8.40
0920
......
........
.
~--
..........
.
...... .......................
~-x~·----·-~··Lr^rr~·rrr^
Irr~-r~*r~r~----~-----~-L-^_-^-r---
·
- ----- -------4 - -II~I~^I
11243
^--.
-I 18.13 _I,-
...
4------4, ------
-4-
·
·
0928 3.95
11057 17.67
10397.51 10127,22
0945 7.71
1743
NA
NA
NA
NNA
NA
NA
NA
NA
NA
NA
NA
NA
_NA
NA
NA
1207
11247 11232 12.10 11237
12.31 1124012.21 1225
~-~----7-~--7~------`111-------~111~--7---1--·1~1~-1·___1_11_1~·__1_·__·- ·3r---"~·-·----C---t--1-·~----~·11--
13.83 11540 14.43
2osep95 --1510 11544 11531 13.02 11535
~~(,~
·
INA
INA
INA
INA
INA
INA
INA
20-Sep-95 NA
3.82 t 0937
14.16
0914 10943 0931
3.91 1.934
, -,
21-Sep-95 1045 11115
1101 7.94
1105
7.38
1109 7.45
1232 1257 1246 8.38 1249 8.61 1252 8.21
21-Sep-95
1339
1351
1356
8.17
6i)- 1403 1348 7.44
1.•-7.80
1632
1-30
.95
9
7.39
1543 1532 7.46
15387.84
22-Sep- 5 iaiii-"
7.99
".4';- i36-7.85
1146
1214
1202 7,29
1206
7.26
1209
7.33
0937 0923
8.59
0928
6.90
0931 8.73
22-Sep-95 0855
NA
NA
NA
NA
NA
54 NA
1030
15.75 11033
5.67 .1036
[5.90
11435 15.03 11440 J5.22 11444 6.23
I
NA
NA
1128
INA
...
.......
...
..
~~
~~I
---- ý....
l---C-NA
I--·NA
N.~ijNA
NA
•.•
ýWA-ýý
"E
NA
NA
NA
1-*1111
LIIII~~I_
- · ~· -----·}NA
INA
I
INA
NA
1343
11444
NA
NA
NA
IPAN
INA
1140
1132
1525
1105
1159
1419
1007
0922
0830
NA
iiq
1458
0934
NA
NA
NA
0837 0754
1100
1044
1309 1250
1135 1121
1549 1535
11453 NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
11026
4.
1~11
INA I
I 1003 NA
INA
NA
NA
1436 1413
1017
1001
0934
0916
82-
1352
1339
1136
1130
1522
1102
1156
1416
1004
0919
0827
NA
NA
NA
NA
NA
0824
NA
11035 NA
IIJJ IA1
0931
0945 0928
1148 1132
1146
1128
1536 1519
1116
1059
446
0840
11012
1514 INA
.~''""
c ^"l"- 1~5i
~ -~1""1*1-
11332
1209 1153
f14if IIAA
1055
NA
0846 INA --1-~-·-t-~---~··---r----c---A 0913 INA
-
052i
IANA
13-Jul-95 1435 Ji500 11447
13-Jul-95 1447 11508 11452
13-Jul-5
1510
11530 11517
...
.. ,
19-Jul-95
LF-1 27GBX20XXX95XX
IANA
1020
18-Jul-954 1316
18-Jul-95 0741
18-Jul-95 08 10
18-Jul-95 0900
18-Jul-95 0928
1117
18-Jul-95
1120
18-Jul-95 1500
1050
19-Jul-95
1407
19-Jul-95
0953
0912
19-Jul-95
0817
20-Jul-95
20-Jul-95 0740
20-Jul-95 1030
I2-Oct-95 1235
1026
1615
1O-Nov-951012
1418
F-1 i 27MWX26XXi9SXX
nin
1340
140011346
13-Jul-95 1326 1134811333
68.81
61.68
~~x"x"~r59.18
~~c1~
11£i1
13-Jul-95 6)84"0jiý---'•
Oý49 N`A
·_·-_~-~-_~--t·~-_·-_~---~
13-Jul-95
- 093-9 091 N
145.96
LF-I
143.46
?--=-1--~T?---·~-~_~-11-1·~1_1~~ ^ZI~II_"=~X~·"
~*"l-T1*"~"
LF-I
130.70
128.20
LF-I
27MWXI7XXB95XX
111.60 109.10
1.87
'39.37
LF- I
27MWXI7XXA95XX
i
141.81
140.63
iS8.ii
7.93
4-
---------
.
-·--------*--~· -,-•-,,---
~-------
..
..
711 p1-h-
J..........
-------t-------
·
. . . ...
.,I.............
-,·-·
...
a........
K
______I
I _i
Appendix A: Dissolved Oxygen Concentration Data for LF-1 (OPTECH, 1996b)
30-Nov-95 0931
30-Nov-95 1445
30-Nov-95 1306
30-Nov-95 1120
30-Nov-95 0930
29-Nov-95 1040
29-Nov-95 0845
30-Nov-95 0930
1105
1621
1440
1240
1113
27MWX62XXX96XX
02-Jan-96 1303
1606
1331
27MW568XXZ95XX
27-Dec-95 0830
1050
27MW568XXZ95ZZ
22-Dec-95 1049
27MWX63XXX96XX
IF-I
LF-1
LFLFLF-I
LF- I
LF- I
LF- I
27GBX22XXA95XX
27MWS68XXA95XX
27MW568XXB95XX
27MW568XXC95XX
27MWX59XXX95XX
27MWX35XXZ95XX
27MWX59XXX95XX
27MW568XXD95XX
LF- I
LF- I
101.46-121.31
101.46
78.63
61.21
204.98
66.21
199.98
61.21
5.89
6.70
3.39
2.37
7.97
3.84
4.51
7.97
1101
1539
1355
1210
1029
1202
0948
1029
3.78
3.7
6.53
3.77
2.20
7.75
5.14
4.95
7.75
1506
1330
1142
1602
1152
0906
1002
5.56
3.90
1.50
7.89
2.09
5.46
7.89
19.79 1336
17.99
1341
17.71
1316
17.05 1321
1031
17.62
1036
18.40 1041
19.27 0929
15.44
1302
1232
13.04
1236
13,57 1242
14.53
1204
16.69
02-Jan-9( 0947
1040
1029
17.96
1033
18.66
17.98 1004
03-Jan-96 1130
07-Feb-94 1104
1219
1203
1135
8.14
19.43
1208 13.80 1213
114018.45 1145
07-Feb-9( 0927
23-Feb-9 1500
1028
1549
1005
17.88 1010
18.47 1539
1054
1531
1345
1202
4.83
6.37
3.88
1.60
1021 7.98
12041158 1.80
5.11I
1032 '0939
1113
1021 7.8
1058
1535
1350
1207
1025
1200
0944
1025
-----·
-I1511
5.87
13353.33
1.02
1147
1007 7.56
1156 2.37
0911 5.91
7.56
1007
1521
1516
1340
1152
1012
6.41
5.95
3.90
1.91 1157 1.76
7.95
1016 8.10
0916
1012
7.95
19.12
1326
18.26
0934
19.99
0939
18.86 0944
1208
14.26
1213
14.75
17.75 1010
18.01
1015
7.64
1148
11.79 1153
18.34
18.65
16.42
0955
19.07
1000
19.39
18.58
1241 11.17
0942
10.33
0947
8.04
11 81
0921
1016
1526
-------
*~~~
r·------
5.78
0926
8.10
5.96
LF-
19.55
1022
19.26
2227
13.95
1223
13.31
18.70 1020
16.23
1024
18.40
1143
12.64
12.97
27MWX61XXX96XX
27MW602XXC96XX
LFLF- I
27MW602XXC96XX
27MWX66XXX96XX
LF-I
27MWX61XXZ96XX
27MWX29XXX96XX
22-Feb-94 0909
20--Feb:9 l215
1014
1304
1000
1251
14.511004
27MWX69XXX96XX
04-Mar-9W 1340
1435
1425
17 05
1430
17.76
1435
15.06
1410
15.48
1415
15.68
1420
15.78
27MWX68XXX96XX
04-Mar-9
1000
1035
1025
155.7
7.6
157.4 7.6
153.2
1010
17.25
1015
17.57
1020
18.68
27MWX66XXX962X
27MWX64XXB96XX
27MWX 64XXA96XX
04-Mar-9f
12-Mar-96
12-Mar-9(
1--r----19-Mar-96
1135
1255
1425
1049
1220
1334
1210
1220
1334
1449
1117
18.13 1215
17.28
13.87
1454
17.86
1459
17.74 '-------*
11.38 1123 11.70 1128
17.99
13.39
17.25
11.53
1155
1459
1311
14.63 1200
14.94
17.74 1444liii11.25
16.10 1205
12.87
18.09
11.47
12.3
1267
11.97
1216
1514'
19 94
10 82
1356
i0.32401i
1636
IS48
ii8.30
39-.0
120
1200
1535
1.1.1
LF-I
LF-I
LF- I
LF-1
LF-I
I .I'- I
11-I
IF-I
MAi
~wX-----37X
S(1 IUCKI
SCIIUCK 2
,--
~~--
300+
---
-- ··- - ·-
22-Mrar-9 120I
22-MN-I
22-Mar-9( 1330
150.)
1128
1242
1416
1015 19.02 0950
15.43 16.49 1531
18.44
1008 1606 0987
1323 '13.08 13281253
21232
2524 12 95
1406
17,79
1217
1529
1412
11295
18.08
17.42
10.28
LF- I
13.59
17 41
1215
16 59
12.47
12142
1416
1440
1106
19.711130
L----
..........
S8.62 0949
13.34
LF- I
4.54
i~~~~-~~~-~~--
1218
LF1037
0932
1158
0951
~~"~I~
'--~--I-----
~~---~--
133.33
0956
17.32
i24•5
1221
18.50
.....
.......
...
Appendix A: Dissolved Oxygen Concentration Data for LF-1 (OPTECH, 1996b)
~h~i~
-t~T"1
155
i;8
220
255
YY
I.F-1
1-F
I
LF-I
LF-I
LF-I
LF-1
LF-1
LF- I
LF-I
L[-I
LF-I
LF- I
F-I
LFiLF-I
LF-I
LF- I
LF-I
LF-I
LF-I
LF-I
27MW567XXA952X
27MWX8 I XXX96XX
27MWX82XXX96XX
27MW568XXX96XX
27MW568XXX96XX
27MW568XXY96XX
27MW568XXX96XX
SX9X
2M
Z7MWS68XXT96XX
27MW56811YD96XX
ISF-I
1k·-I
27
X66XXX9)63X
27MWXJOXXX962X
LF- I
27MWX8XXX96XX
LF-I
7MWXS4XXZ96XX
LF-1L
27MWX71XXX 962X
Lf-ij37MWwX-69XXX :962X
TO-I
15-Apr-96
1430
23-A1221
23-Apr- ISIS
23-Apr-96 1410
15- 1430
15-Apr-6 1600
01-Ma-
101
195-200
177-182
154-159
148-153
181-186
146-151
163-168
149-154
•I27N1',.X86XXA96XX_148-1505
St-
11:-I
03MPX86XXB96XX
27MPX86XXC96XX
27MPXB6XXD96XX
27NII'XK.XS7(XX
YXX
27KIWXS7XXX96XX
iL,.
11140
16.16
IIJ.L05I
IJ.
'-~"~"'
L--,J·
...........
L
16.47
145
'
15.41
11439
116.77 11444 115.14
---~·---c----*---·r-----·
--12.34
0929
61
.39
( ~II~
0934
7.22
1012
.
146.07
.
156.42 133.5-136
156.42
11-9-1215
156642 975-100
I1t42
1304
1604
1457
1543
1706
1533 111.1411538
1255
16.65 1258
19.69 1603
1601
1450
12.69 1454
1533
11.14 1538
1655
10.83 1701
1348 1203 1350
1104 1100
1259 1249
1336
1339
1429 1419
1626
1616
1622
1612
0948 0935
1150
1140
1617 1607
12.10
13.08
1139
7.31
3.83
9.11
9.19
1.57
8.62
1102
1254
1338
1424
1621
1617
0940
1145
1612
11.49 11543
15.50
1304
18.31 1605
14.89 1457
11.51
15.47
19.32
15.61
11.49
11.51
11523
1247
1556
1440
1342
19.99
1346
13.28
1104
1259
1339
1429
1626
1622
0948
1058
1239
1332
1349
1606
12.66
18.53
9.56
462
3.73
10.55
1244
1334
1354
1611
11.98
5.63
3.84
1359 6.33 1404 6 74
1150
8.63
1617
0920
1045
1537
9.51
400
8.65
0925
1050
1542
9.28
2.93
8.22
0930
1.58
1013
6.64
1018 6.489
ý-63-- 6.39
3.95
1305
6.96
1526 6.77 1531 6.64
102357
10.15 1053 10.16
1339
1.26
1.25
1.31
8.96
9.46 1602 9.22
4.54
5.89
3.01
7.02
1405 6.91 1410 6.86
11.98
12.77
11.49
745
3.82
9.07
8.24
1.68
8.588
1608 9.17
6.14
1008
6.58
9.91
.82
1516 7.15
1043 10.25
1329
1.48
8.39
155210.08 1557
6.53
6.65
1042 2.53
1355 7.17
17-inn- 1540 1653 1643 9.51
6.64
1032
1022
18-inn- 0905
18-Jun-9611215
11400 11350
1648
1027
9.50
6.58
1653
1032
9.48
6.58
7.05
1608
0942
1245
110251•-10
3.87-- 13303.88--
7.95
9.28
2.59
8.17
--
123 11107 11.39 11112
26-Jul-961 ns - LI
1.43
6.22
6-97
...........
416
0Oo
1117
1205
1245
I1.14
1401
f=
.........
1.45
6.22
6.97
41%
403
11
1409 7 01
....... ·"4"
.......
..... --,-.-4. ......---
1521
1048
1334
1047
1400
7.17
8.11
1557
8.39
1028 6.32
1315 3.91
1536 6.74
1602
864
1607
862
1033
6.28
1038
6.27
1541
6.66
10.09 110310.07 110810.0511139.95
1349 1.10
1612 8.67
1102 6.02
1415 6.80
fi-52
10.53
6.41
14.14
.9541.178
1414
2.0711051.8211101.711115170
-1255 4.84- 1300 4.24
1613 10.34 1618 10.20
7]6.56
3.77
1250 3.81
~~l~~'~~~~c-----·l-·------~----7..70
1530
17.55
jI.57
110141,58 10191.59
26-JnI-9610905 11123 11107 11.3911112
26-Jul-96 0920
1211 1155 6.23
1200
6.95 1240
26-Jul-96
441
11ii
1320
1146
09-Jul-90
8 14 1432
1444 1427
* -·· 4"
..
lllxl1-~4
1050 12.55
'Z"f-1"7TTI~
8.60
11600
---.8--------E·------ ~~~xl~-r----r----t---r-·----
9
26-i•utjO9S
..
·
12.26
•-~~
•--•- +_---------13.34
1058
1-605
1555
1
c----~------t------r----·--·c·----
11.98
12.05
12.92
7.40
3.81
9.04
8.85
1551
1154
1404
1637
1157
1440
i3ou
------
13.68
135212.98
6.60
9.85
.80
8.40
6.54
6.67
18-un-1450
.
·
-" ~~~~^"" ~
~7"---r"~"
--------- ------~
---- t-----~-----Jxxlx~---~t-----·l---------·I --------· (---------(--------·
1528 10.81
6.20
1048
1320
1541
1143
1354
1627
1147
1430
.
'
1523 11.26
1543
....I
10.82 1706 11.06 1646 14.98 1649 13.15
1053
1325
1546
1148
1359
1632
1152
1435
1058
1330
1551
1154
1404
1637
1157
1440
!
------I
----~
--" ---
111.26
16.95 1252 12.20
14.39 1558 18.91
18.02 1444
1605
6.24
3.88
6.66
9.85
.91
843
660
6.69
27-Jun- 0927
27-Jun- 1211
27-Jun- 1445
13-Jun-961010
13-Jun-96 1300
13-Jun- 961515
17-un- 61010
17-Jun-61325
~----~
,= :
-7
-- IS-Ar-96 115 1340 1133015.39 11335
.57 11340 3.46 1320 9.9
--------- f--------- --- t--~-~-·(---i-··C----~----
181
159-164
27MWX68XXX962X
27MWX83XXX96XX
2WXSOXXD962X
ImO
I
.7
51
192-197
[f-I
LF-I
LF-I
LF-I
LF- I
I.F-I
V,
01-Apr-961110611151 11140
01-May 0955
102
27MW568XXB96X3
1219
01-May27MW568XXY9x3____ 108
157.96
27MWXSOXXD96XX
1306
17-Apr-96
291,2
288-293
II-Jun- 1306
2iMWX62XXX962X
220-225
12-Jun- 1500
27MWXXXX96XX
13-Jun- 1350
184-189
27MWXBIXXX962X
250-255
14-Jun-96 0825
27MWX4 IXXA962X
201-206 25-Jun- 1006
27MWX6XXX962X
26-Jun-96
1439
183-188
27MWXS8XXX962X
27MWX60XXX962X
27MWXXXX96XX
I6.3I
. _ 112
.
ý_ !ý
3ýJO93
12.00 11130
115.39 11135
~"^1"Cl~rxrrr~Errr--~
-----L-1-t-1-~-'·*-~XXIII~I^-1~-~~"I~'I"1~-~CT"=IIZ~-*I
i150-7 1113 152
128 j15i7 1160f1-3 1---0"5529
14ý25
11,80 *---*---·C----~---OlApr-96--__#,------------------- -------------------------I
I~----~-----*-------09
58
71.31
1039
68.81
.22:Se[95
P1042 1033
7..00 11036 7.48
I----~
Oý39
1l-·-----~
1
1.4ý
Lýý
12.15
1146
12.32
1149
12-Ar-96 1101
1204 11J54 .I1496 1159 14.05 1204
n
~I
k
--
1150
1449
10.07
16.32 1200 14.66
16.90
15.22
-*
16.83
17.37 0943
::.,-.,..-.--4
6
11.97 1i14
11.76 11151
1300
k-
9.94
7.03
3.99
1628 9.81
1002 6.92
1305 14.35
...
....
...
8.08
1545 18.24
;·----r·-··--·---r---·---E-I-----
1617
8.57
1107 6.39
1420 6.74
1633
1007
....
9.71
6.82
4.82
...
8.4.
1622 8.44
1112 590
1425 6.72
1638
1012
11320
.....
-T-"
9.56
6.73
5.61
•
......
1.57 1004 1,56
1057
1052 1.51
1057 1.35
·
11150 16.36
1230 16.89 i
nIof 109~ 1111%
m 1943211fs-
1102
I
1.36
----
-*-)--
iin-l·-·· -1·-·-··-·I
1121
112%
1407 HAIS 1412? 8.13
........
I----
-
1ý117 jk30
j1422 [8-22
L .........
.
Appendix A: Dissolved Oxygen Concentration Data for LF-1 (OPTECH, 1996b)
LF-I
LF-I
LF-1
LF-I
27MW568XXZ963X
27MWXS4XXX96XX
27MWX59XXX96XX
27MWXS6XXX9XX
27 i 37x
1341
2
LF127MWX73XXX962X
LF-I
27MWX65XXX962X
LF-I 127MWX72XXX962X
LF-I
27MWX69XXX962X
------ I--------~_~·I1-2·"---1----;
LF-1
LF-I
j 27MPX74XXA96XX
27MPX74XXB96XX
LF-:
127Mi'X74XXC96XX
LF-I
J27MPX74XXD96XX
-·---1·---------·---~
LF-I
j27MPX74XXE96XX
|
.......
325-330
149-154
11540
11~-~111.
·III~XII~l~
1322
- I...........
28-Jun.
18-Jun
1215
i15s
15
15J1553
1443
IIII~-·XI*I^I~··~X^IIX
·IIXIII~X~-·I
ii ..I
-
-
1540 8.08
h
·I~-·^·~X~*IIIIII_-X11IIXI
Illlll^ill~-·IX
IXI11~1I
·
172.35-174
29-Jul-960855
1018 0955
3.93 11000 3.94 11005 3.96 0945 3.96 10950 3.94
29-Jul-96i 06-55
1032
1037
8.55
11042 8.55 1022 8 45
157-160
8.55
1027 3.47
143-145 29-Jul-96
5.91
s-K.4,
3_47._ 5.90 1149 5.90 I 129 15.911134 5.91 +-------1-------------(-----546o"
97ulk
·-··
0855
123-126
5.27
I3340 I----C----C-----C---5.38 ~---------C--------S L
L
·--------1-----·-I,
•
4-~------- · ·--- ~----------- ~-----------~-------r~--------·
li -104-106
8.27 11444 18.30 1422 18.31 11427 8.31 1432 18.28 !
913
8.26 I'442
84-87
8.21 E--~------~--~------~--------11523 8.23 11528 18.19
8.20
Ii---_·-~-~-~-~-t----t----~~-z~-~-~--·
29-Jul-9610855
11540 11518 -------1150818.21 11513 ---------~-------i--------~7---~----(----*----------*-------·
I~
42-45
25-JuI-9610920
1409
1353 .54
1403I .54
1358 i.54
11348 11.42 3
~--------i-------- t • ----&
-4- ~
33338
I
1425 1403
63
1413
.70
1408
11348 11.04 11353 .84
.59
1.77 I
-1434-
lu----
··
f27MPX59XXE96XX
27MWX61XXZ962X
1407
6.27
8.15
3.77
219-223
^."I^II*L~*X1X^.~.IX~··111
193-198
iiM27PX74XXF96XX
LF-I
F:-1
iN6i
1600
6.43
F
4 ~I
----·l----·C-··---6.20
1145
8.39
1125 3.03
1402
1412 3.80
4.33 1327 4.03 132 13.l96 1337 3,82 11342 3.74
1347
3 751 1352 13.77
8.32
11351 8.23 ---11246
111.23-·11251 ------·
10.38 11256
110.10 1301
9.91 E---4·
11306 9.74
1311-- .531
113161953
·
-·
E----~--*----- ~---4----·
---...
.4-.... -. '4......1200
11210
.94
3.93 13.90 11330 1043 11l35 11.30 31140 1.13 11145 1.09
1125
1150 i1.03 1155 1.99
1125
1108 t·"---2.56 11118 !~"~X"LL"*~~^"~.~""I*~~
2.87
1043
2.77
2.58 11113 '~"XI*I~L"t'~"~·I
2.55
11018 13.70
13023 2.99 1028 12.96 1033 2.92 11038
1048
2.73
-^~"~Z~^T~"I~*
--- ~---fr------~~------~-----~--~I·--:
---I--I--....
..
6.37 11453
6.44114586.46 11413 1.63 31418 .421423 1.66 1428 3 .04 1J4 3 3 4.96 1438 5.85
6.24
3505 13448
I
.53
1133 .54
.26
11203 .22
13208 .24
1123 1.75
1128 .52
1138 .45 11143 .35
.28
.30
8.iS
8.60
600
8.67
3605 8.73
52517.50
1530 7.55
13535
17.76
3.29
8.43
·
111"
Tg....................
f ........
1...................
•....................
i ...........g.................
..................
ff
.....................
6.20
1555
7.95 1140
3.78
8.49 11346
11205
.95
-
L
L
dW-if
- -5- --
·
S1-Jul-96j0900
i144
ijj5-XII
5.28
.54
1.320
?04 38
1325-
11343 11.42 1--
i.
..
Q
I1358
F::--··-|......
..
............ i, ......... A----
----~
·-..
.
.
. 4...
...
"t, . ...
-----
10.2 Appendix B: Explanation for Equations 7-1 and 7-2
If the total time of bioremediation was only dependent on the time needed for the
contaminant to biodegrade, the zeroth order and first order equations would be:
C = Co - (ko*to), and
(A-l)
C = Co*exp(-kl*t1 ),
(A-2)
and the bioremediation time would be derived by rearranging the equation and isolating t:
to = (C - C) / ko,
(A-3)
t, = (-1 / kj) * In (C / Co).
(A-4)
If the total time of bioremediation was also dependent on the time for the biozone to be
established, tb, equations A-i and A-2 would be modified:
C = Co - [ko*(to - tb)],
(7-1)
C = Co * exp[-k,*(t, - tb)].
(7-2)
Now if the bioremediation time is derived by rearranging and isolating t:
to= [(C - C)/ ko] + tb,
(A-5)
t, = [(-1 / k,) * In (C / Co)] + tb.
(A-6)
Equations A-5 and A-6 demonstrate that the bioremediation time is greater when the time
to reach steady state is taken into account, as shown in Equations 7-1 and 7-2.
Appendix B. Spreadsheet Calculations for Conceptual Design
Location
R (ft) al R
of Well
1
2
3
4
5
6
7
8
9
10
11
12
13
14
1500 0.06
720 0.125
960 0.094
1200 0.075
1500 0.06
1500 0.06
1320 0.068
1320 0.068
1800 0.05
1500 0.06
960 0.094
1080 0.083
1500 0.06
1200 0.075
that
erfc(-(1
2.4
2.5
2.2
2.4
2.8
2.7
2.4
2.6
6*a*(tha t 1.5)/3/R))
1.930497262
1.871406366
-~---~
1.898778508
3
2.8
2.6
2.4
2.4
2.5
that)/(SQRT(1
1.919419896
--
1.930497262
1.930497262
1.923167114
-~~---~~
1.923167114
1.93112827
1.930497262
1.898778508
1.913124088
1.930497262
1.919419896
Chat
0.9652
0.9357
0.9494
0.9597
0.9652
0.9652
0.9616
0.9616
0.9656
0.9652
0.9494
0.9566
0.9652
0.9597
Ccontam
(pglL)
64
10
30
30
48
26
26
10
0
0
BOLD:
PCE
plain:
TCE
Required Substrate: Required Oxygen:
substrate
Oxygen
Cinject
Cinject
(pg/L)
(pg/L)
(mg/L)
(mg/L)
4700
53.87952
53.87952
4700
2000
2000
24.86747
24.86747
39.78795
2800
2800
2000
1500
1500
4869.2118
57.581848
56.751767
4897.313
2072.005
2072.005
25.860956
25.860956
41.206949
2900.807
2949.2645
2090.821
1554.0038
1562.9722
28.2
n/a
n/a
22.72
12
29.2153
n/a
n/a
n/a
16.8
9.09
4.16
9
9
n/a
n.a
23.6738
12.432
12.432
n/a
n/a
n/a
17.4048
9.57458
4.34891
9.32402
9.37783
Appendix B. Spreadsheet Calculations for Conceptual Design
time to
Required Phosphate: reach
Required
Required Required Ammonium:
steady Q (ft3lhr)
Phosphorus Phosphate
Nitrogen Ammonium
Cinject (pg/L) state: t
(iglL)
(pglL)
Cnjct(glL)
(pglL)
(pglL)
(yrs)
17069.2
5
144.032258 149.21778
47
282.857143 293.040709
220
5
4915.92
0.051510056 0.1578534 0.16870029
0
0
0
0.16626836
8011.13
5
0.1578534
0.051510056
0
0
0
11834.6
5
144.032258 150.078947
47
282.857143 294.731907
220
17069.2
5
61.2903226 63.4969277
20
0
0
0
17069.2
5
61.2903226 63.4969277
20
257.142857 266.400644
200
0.07576608
13769.1
5
0.07285541
0.023773872
0
0
0
13769.1
0.07576608
5
0.023773872 0.07285541
0
0
0
22531.3
5
0.228229 0.2934375 0.30390265 0.038038195 0.11656866 0.12072596
17069.2
5
85.8064516 88.8956988
28
0
0
0
8011.13
90.3806855
5
85.8064516
28
0
0
0
9954.74
5
61.2903226 64.0735465
20
0
0
0
5
17069.2
45.9677419 47.6226958
15
0
0
0
11834.6
45.9677419 47.8975362 ----------I
I
0
I 0
45.9677419
I
SS
seepage drawup
(ft) at d (ft)
velocity
(ft/day) distance
d
0.986301
0.591781
0.723288
0.854795
0.986301
0.986301
0.90411
0.90411
1.084932
0.986301
0.723288
0.798904
0.986301
0.854795
2.023005
0.552555
0.919667
1.380608
2.023005
2.023005
1.617221
1.617221
2.704602
2.023005
0.919667
1.152563
2.023005
1.380608
assuming
regional
drawdown
velocity =
<<<aquife
0.86
r thicknes
ft/day
s
0.001
0.001
0.001
0.001
0.001
0.001
0.001
0.001
0.001
0.001
0.001
0.001
0.001
0.001
Appendix B. Spreadsheet Calculations for Conceptual Design
Total Oth order
bioremediation
time (yrs)
n/a
n/a
Total 1st order
bioremediation
time (yrs)
5.000010052
5.000011152
5.000011152
5.000010052
5.000000852
5.000000852
5.000004647
5.000004647
5.000007992
7.719930409
13.87280115
13.87280115
7.719930409
5.739498976
5.739498976
11.19814401
11.19814401
12.82400408
5.000003578
6.758906911
5.000003578
5.000000852
6.758906911
5.739498976
n/a
n/a