&EPA
United States
Environmental Protection
Agency
EPA-600/R-05/041
April 2005
Evaluation of Fugitive
Emissions at a Former
Landfill Site in Colorado
Springs, Colorado Using
Ground-Based Optical
Remote Sensing
Technology
VRPM OP-FTIR/Scanner
Configuration y
K
Hot Spot
A
Hot Spot
B
-------
EPA-600/R-05/041
April 2005
Evaluation of Fugitive Emissions at a
Former Landfill Site in Colorado
Springs, Colorado Using
Ground-Based Optical Remote
Sensing Technology
by
Mark Modrak
Ram A. Hashmonay
Ravi Varma
Robert Kagann
ARCADIS G&M, Inc
4915 Prospectus Dr. Suite F,
Durham, NC27713
Contract Number: EP-C-04-023
Work Assignment Number: 0-25
Project Officer: Susan A. Thorneloe
National Risk Management Laboratory
Air Pollution Prevention and Control Division
Research Triangle Park, NC 27711
U.S. Environmental Protection Agency
Office of Research and Development
Washington, DC 20460
-------
Abstract
A former landfill site located in Colorado Springs, Colorado was assessed for landfill gas
emissions in support of reuse options for the property. The current owners of the landfill and
the State of Colorado requested assistance from the EPA Region 8 Office, and the Office of
Superfund Remediation and Technology Innovation, Technology Integration and Information
Branch to perform a site assessment to search for the presence of any fugitive gas emissions
from the site.
The focus of this study was to evaluate fugitive emissions of methane and volatile organic
compounds at the site in support of the reuse objectives, using a scanning open-path Fourier
transform infrared spectrometer, open-path tunable diode laser absorption spectroscopy, and
an ultra-violet differential optical absorption spectrometer. The study involved a technique
developed through research funded by the EPA's National Risk Management Research
Laboratory that uses ground-based optical remote sensing technology, known as optical remote
sensing-radial plume mapping. The horizontal radial plume mapping (HRPM) method was used
to map surface concentrations, and the Vertical Radial Plume Mapping (VRPM) method was
used to measure emissions fluxes downwind of the site.
The HRPM surveys detected the presence of a methane hot spot in the Northeast quadrant of
the site, and the peak concentration for this hot spot was greater than 0.4 ppm above ambient
background levels. Another methane hot spot was detected in the Southeast quadrant of the site,
and the peak concentration for this hot spot was greater than 0.5 ppm above ambient
background. The VRPM survey measured an average methane flux from the site of 4.9 g/s. The
location of the peak of the reconstructed methane plume agrees well with the location of the hot
spots detected during the HRPM surveys. This suggests that emissions from the two hot spots
are a major source of the methane plume detected during the VRPM survey.
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Foreword
The U.S. Environmental Protection Agency (EPA) is charged by Congress with protecting
the Nation's land, air, and water resources. Under a mandate of national environmental laws,
the Agency strives to formulate and implement actions leading to a compatible balance
between human activities and the ability of natural systems to support and nurture life. To meet
this mandate, EPA's research program is providing data and technical support for solving
environmental problems today and building a science knowledge base necessary to manage
our ecological resources wisely, understand how pollutants affect our health, and prevent or
reduce environmental risks in the future.
The National Risk Management Research Laboratory (NRMRL) is the Agency's center for
investigation of technological and management approaches for preventing and reducing risks
from pollution that threaten human health and the environment. The focus of the Laboratory's
research program is on methods and their cost-effectiveness for prevention and control of
pollution to air, land, water, and subsurface resources; protection of water quality in public
water systems; remediation of contaminated sites, sediments and ground water; prevention
and control of indoor air pollution; and restoration of ecosystems. NRMRL collaborates with
both public and private sector partners to foster technologies that reduce the cost of
compliance and to anticipate emerging problems. NRMRL's research provides solutions to
environmental problems by: developing and promoting technologies that protect and improve
the environment; advancing scientific and engineering information to support regulatory and
policy decisions; and providing the technical support and information transfer to ensure
implementation of environmental regulations and strategies at the national, state, and
community levels.
This publication has been produced as part of the Laboratory's strategic long-term research
plan. It is published and made available by EPA's Office of Research and Development to
assist the user community and to link researchers with their clients.
Sally Gutierrez, Acting Director
National Risk Management Research Laboratory
in
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EPA Review Notice
This report has been peer and administratively reviewed by the U.S. Environmental
Protection Agency and approved for publication. Mention of trade names or commercial
products does not constitute endorsement or recommendation for use.
This document is available to the public through the National Technical Information
Service, Springfield, Virginia 22161.
IV
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Contents
Section Page
Abstract ii
List of Tables vii
List of Figures viii
Acknowledgments ix
Executive Summary x
1 Project Description and Objectives 1-1
1.1 Background 1-1
1.2 Project Description and Purpose 1-3
1.2.1 Horizontal RPM 1-4
1.2.2 Vertical RPM 1-5
1.3 Quality Objectives and Criteria 1-5
1.4 Project Schedule 1-7
2 Testing Procedures 2-1
2.1 HRPM Measurements 2-2
2.1.1 Northwest Quadrant 2-2
2.1.2 Southwest Quadrant 2-3
2.1.3 Northeast Quadrant 2-3
2.1.4 Southeast Quadrant 2-3
2.2 VRPM Measurements 2-3
2.3 OP-TDLAS Measurements 2-3
3 Results and Discussion 3-1
3.1 The Horizontal RPM Results 3-1
3.2 The Vertical RPM Results 3-2
3.3 VOC and Ammonia Results 3-2
3.4 OP-TDLAS Results 3-4
4 Conclusion 4-1
5 QA/QC 5-1
5.1 Equipment Calibration 5-1
5.2 Assessment of DQI Goals 5-1
5.2.1 DQI Check for Analyte PIC Measurement 5-1
5.2.2 DQI Checks for Ambient Wind Speed and Wind Direction
Measurements 5-2
5.2.3 DQI Check for Precision and Accuracy of Theodolite Measurements . 5-3
5.3 QC Checks of OP-FTIR Instrument Performance 5-3
5.4 Validation of Concentration Data Collected with the OP-FTIR 5-4
5.5 Internal Audit of Data Input Files 5-4
-------
Contents (concluded)
Section Page
5.6 OP-TDLAS Instrument 5-4
6 List of References 6-1
Appendix A: OP-FTIR Mirror Coordinates A-l
Appendix B: OP-TDLAS Configuration Path Length Distances B-l
Appendix C: Methane Concentrations C-l
VI
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List of Tables
Table
1-1 Summary Information on the ORS Instrumentation Used in the Study
1-2 Detection Limits for Target Compounds 1-6
1-3 Schedule of Work Performed at the Site 1-7
3-1 Moving Average of Calculated Methane Flux, CCF, Wind Speed, and Wind
Direction for the Downwind As-Built Area Upper Cell 3-2
3-2 Minimum Detection Levels by Compound for the OP-FTIR Instrument 3-4
3-3 Average Methane Concentrations aove Ambient Background Levels
Measured with the OP TOLAS System 3-4
5-1 Instrumentation Calibration Frequency and Description 5-1
5-2 DQI Goals for Instrumentation 5-2
A-l Distance and Horizontal Coordinates of Mirrors Used in the HRPM Survey of
Northwest Quadrant A-l
A-2 Distance and Horizontal Coordinates of Mirrors Used in the HRPM Survey of
Southwest Quadrant A-l
A-3 Distance and Horizontal Coordinates of Mirrors Used in the HRPM Survey of
Northeast Quadrant A-l
A-4 Distance and Horizontal Coordinates of Mirrors Used in the HRPM Survey of
Southeast Quadrant A-l
A-5 Distance, and Horizontal and Vertical Coordinates of Mirrors Used in the VRPM
Survey of Northern Border A-2
B-l Distance of Path Lengths Used in OP-TDLAS Configurations B-l
C-l Methane Concentrations Found during the HRPM Survey of the
Northeast Quadrant C-l
C-2 Methane Concentrations Found during the HRPM Survey of the
Northwest Quadrant C-2
C-3 Methane Concentrations Found during the HRPM Survey of the
Southeast Quadrant C-3
C-4 Methane Concentrations Found during the HRPM Survey of the
Southwest Quadrant C-4
C-5 Methane Concentrations Found during the VRPM Survey C-5
vn
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List of Figures
Figure Page
E-l Map of the Site Detailing the Location of the HRPM Survey Areas xi
E-2 Map of the Site Detailing the Location of the VRPM Configurations xi
1-1 Colorado Springs, Colorado, Site 1-1
1-2 Map of Colorado Springs Site Showing the Location of the HRPM
Survey Areas 1-2
1-3 Map of the Colorado Springs Site Showing the Location of the VRPM
Configuration 1-2
1-4 OP-FTIR Instrument/Scanner 1-3
1-5 Example of a HRPM Configuration 1-4
1-6 Example of a VRPM Configuration 1-5
2-1 Passive Vent Sealed During the HRPM Surveys 2-1
2-2 Schematic of the HRPM Configuration Used in the NW Quadrant 2-2
2-3 Schematic of the HRPM Configuration Used in the SW Quadrant 2-3
2-4 Schematic of the HRPM Configuration Used in the NE Quadrant 2-3
2-5 Schematic of the HRPM Configuration Used in the SE Quadrant 2-3
2-6 OP-TDLAS System 2-4
2-7 Schematic of the OP-TDLAS Configuration Used on September 10 2-4
2-8 Schematic of OP-TDLAS Configuration Used on September 11 2-4
3-1 Average Surface Methane Concentration Contour Map of the Colorado
Springs Landfill 3-1
3-2 Average Reconstructed Methane Plume from the VRPM Survey 3-3
3-3 Methane Flux and Prevailing Wind Direction Measured During the
VRPM Survey 3-3
5-1 Comparison of a Spectrum Measured at the Site to Reference Spectra of
Gasoline 5-4
5-2 Post-Colorado Springs Comparison of Methane Concentrations Measured
with the OP-TDLAS and OP-FTIR Instruments 5-5
Vlll
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Acknowledgments
This study was jointly sponsored by the United States Environmental Protection Agency
(EPA) Region 8 Office, and the Office of Superfund Remediation and Technology
Innovation, Technology Integration and Information Branch under its Monitoring and
Measurement for the 21st Century (21M2) initiative. The 21M2 initiative is intended to
provide EPA staff with resources to apply new approaches to real site problems.
IX
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Executive Summary
A former landfill site located in Colorado Springs, Colorado was assessed for landfill gas
emissions in support of reuse options for the property. The landfill is approximately 40 acres,
and landfill operations took place on the site from about 1957 to 1980. The landfill accepted
waste from both commercial and residential operations. Several volatile organic compounds
(VOCs) are known to be present in soil gas and groundwater beneath the landfill. The current
landfill owners and the State of Colorado requested assistance from EPA to perform a site
assessment searching for the presence of any fugitive gas emissions from the site. This
assessment was necessary due to the potential adverse health effects associated with exposure
to landfill gas. The EPA Region 8 Office requested assistance with this study through the 21M2
program to utilize innovative approaches for performing an assessment at the site.
The focus of this study was to evaluate emissions of fugitive gases and VOCs at the site in
support of the reuse objectives, using an open-path Fourier transform infrared (OP-FTIR)
spectrometer and an open-path tunable diode laser absorption spectroscopy (OP-TDLAS)
system. The OP-FTIR instrument provided the critical measurements in the current study. The
OP-TDLAS provided non-critical, supplemental data. The study involved a technique
developed through research funded by the U.S. EPA's National Risk Management Research
Laboratory (NRMRL) that uses ground-based optical remote sensing technology, known as
optical remote sensing-radial plume mapping (ORS-RPM) (Hashmonay and Yost, 1999;
Hashmonay et al., 1999; Wu et al., 1999; Hashmonay et al., 2001; Hashmonay et al., 2002).
The site assessment consisted of one field campaign performed during September 2003 by
ARCADIS and EPA personnel. Figure El presents the overall layout of the site, detailing the
geographic location of each horizontal radial plume mapping (HRPM) survey area. Figure E2
shows the location of the vertical radial plume mapping (VRPM) configuration that was used
to collect data for emission flux calculations.
HRPM surveys were done in the NW, SW, NE, and SE quadrants to search for surface
emissions of methane, ammonia, and VOCS (see Table 1 of the report for a list of target
compounds). A VRPM survey was done along the northern border of the site to measure
emissions of methane, ammonia, and VOCS downwind of the site. The OP-TDLAS instrument
was deployed along the surface of the site, and on a slope adjacent to the southern boundary of
the site to provide additional information on methane concentrations.
x
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1\
Northwest
Quadrant
Northeast
Quadrant
OP-FTIR/Scanner
Southwest
Quadrant
Southeast
Quadrant
Figure E-1. Map of the Site Detailing the Location of the HRPM
Survey Areas.
N
W « I ' E
OP-FTIR/Scanner
Far
Mirror
___ , Near
Scissors Jack Mirror
(3 Mirrors)
-f
I Prevailing
Wind
Direction
Figure E-2. Map of the Site Detailing the Location of the
VRPM Configurations.
XI
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HRPM Results
The HRPM surveys of the site detected the presence of a methane hot spot in the Northeast
quadrant of the site. The peak concentration for this hot spot was greater than 0.4 ppm above
the determined ambient background level of 1.55 ppm, which was the lowest methane
concentration measured during the field campaign. Another methane hot spot was detected in
the Southeast quadrant of the site. The peak concentration for this hot spot was greater than 0.5
ppm above ambient background.
VRPM Results
The VRPM survey measured an average methane flux from the site of 4.9 g/s. The location of
the peak of the reconstructed methane plume agrees well with the location of the hot spots
detected during the HRPM surveys. This suggests that emissions from the two hot spots are a
major source of the methane plume detected during the VRPM survey.
VOC and Ammonia Results
All data sets from the HRPM and VRPM surveys were searched for the presence of VOCs and
ammonia. The analysis detected the presence of gasoline (primarily octane) during the HRPM
survey of the Northeast quadrant. However, this is attributed to emissions from the gasoline
generators used in the field campaign, which were located upwind of the measurement
configuration during the HRPM survey of the Northeast quadrant. The measured gasoline
concentrations ranged from below the detection limit to 23 ppb. Analysis of the other data sets
did not detect VOCs or ammonia at levels higher than the minimum detection levels of the
OP-FTIR instruments.
OP-TDLAS Measurements
The OP-TDLAS survey of the surface of the site found average methane concentrations
between 0.47 and 0.53 ppm above the ambient background level of 1.55 ppm. The surface
methane concentrations measured with the OP-TDLAS system agree fairly well with the
methane levels measured during the HRPM surveys.
The survey of the slope along the southern boundary of the site found relatively higher methane
concentrations. The largest average methane concentration detected was 1.34 ppm above
ambient background. The relatively larger standard deviations found during the slope survey
suggest that methane hot spots were present along the slope.
xn
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Chapter 1
Project Description and Objectives
1.1 Background
A former landfill site located in Colorado Springs,
Colorado was assessed for landfill gas emissions as
part of an effort to rehabilitate the site as a recre-
ational facility. The landfill is approximately 40 acres
and accepted waste from both commercial and
residential sources from about 1957 to 1980. Several
volatile organic compounds (VOCs) are known to be
present in soil gas and groundwater beneath the
landfill. The current owners of the landfill and the
State of Colorado requested assistance from the EPA
to perform a site assessment to search for the pres-
ence of any fugitive gas emissions from the site. This
assessment was necessary due to the potential ad-
verse health effects associated with exposure to
landfill gas. The EPA Region 8 Office requested
assistance with this study through the 21M2 program
to utilize innovative approaches for performing an
assessment at the site. Figure 1-1 shows a picture of
the site.
The focus of this study was to evaluate emissions of
fugitive gases, such as methane and ammonia, and
Figure 1-1. Colorado Springs, Colorado, Site.
VOCs at the site in support of the reuse objectives,
using an pen-path Fourier transform infrared (OP-
FTIR) spectrometer and an open-path tunable diode
laser absorption spectroscopy (OP-TDLAS) system.
The OP-FTIR instrument provided the critical mea-
surements in the current study. The OP-TDLAS
system provided non-critical, supplemental data on
methane concentrations. The study involved a tech-
nique developed through research funded by the U. S.
EPA's National Risk Management Research Labora-
tory NRMRL that uses ground-based optical remote
sensing technology, known as optical remote sens-
ing-radial plume mapping (ORS-RPM) (Hashmonay
and Yost, 1999; Hashmonay et al., 1999; Wu et al.,
1999; Hashmonay et al., 2001; Hashmonay et al.,
2002). The assessment identified emission hot spots
(areas of relatively higher emissions), investigated
source homogeneity, and calculated an emission flux
rate for each compound detected at the site. This
information can be used to identify specific areas at
the site in need of better gas control and to assess
whether or not better controls should be implemented
at the site as a whole. Concentration maps in the
horizontal and downwind vertical planes were gener-
ated using the horizontal radial plume mapping
(HRPM), and vertical plume mapping (VRPM)
methods, respectively.
The study consisted of one field campaign performed
during September 2003 by ARCADIS and EPA
personnel. The Colorado Springs site was divided
into four areas. Figure 1-2 presents the overall layout
of the site, detailing the geographic location of the
HRPM survey areas. The red dot indicates the posi-
tion of the OP-FTIR instrument during the HRPM
surveys. Figure 1-3 shows the location of the VRPM
configuration used at the site. The blue dot indicates
1-1
-------
Evaluation of Fugitive Emissions at a
N
Northwest
Quadrant
'
OP-FTIR/Sc
Northeast
Quadrant
OP-FTIR/Scanner
Southwest
Quadrant
Southeast
Quadrant
Figure 1-2. Map of Colorado Springs Site Showing the Location
of the HRPM Survey Areas.
N
OP-FTIR/Scanner
Far
Mirror
Scissors Jack
(3 Mirrors)
Near
Mirror
W « I > E
VPrevailing
Wind
Direction
Figure 1-3. Map of the Colorado Springs Site Showing the
Location of the VRPM Configuration.
1-2
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Former Landfill in Colorado Springs, Colorado
the location of the OP-FTIR; the blue diamond
indicates the location of a scissors jack (vertical
structure) on which were placed three mirrors used in
the configuration; and the blue squares indicate the
location of the surface mirrors.
1.2 Project Description and Purpose
The objectives of the study were to identify major
emissions hot spots by collecting OP-FTIR data and
creating surface concentration maps in the horizontal
plane, measure emission fluxes of detectable com-
pounds downwind from major hot spots, and demon-
strate the operation and function of the optical remote
sensing (ORS) technologies.
The ORS techniques used in this study were designed
to characterize the emissions of fugitive gases from
area sources. Detailed spatial information is obtained
from path-integrated ORS measurements by iterative
algorithms. The HRPM method involves a configura-
tion of non-overlapping radial beam geometry to map
the concentration distributions in a horizontal plane.
This method can also be applied to a vertical plane
downwind from an area emission source to map the
crosswind and vertical profiles of a plume. By incor-
porating wind information, the flux through the plane
is calculated, which leads to an emission rate of the
upwind area source. An OP-FTIR sensor was chosen
as the primary instrument for the study because of its
capability of accurately measuring a large number of
chemical species that might occur in a plume.
The OP-FTIR spectrometer combined with the ORS-
RPM method is designed for fence-line monitoring;
real-time, on-site hot spot detection and source
characterization; and emissions flux determination.
An infrared light beam modulated by a Michelson
interferometer is transmitted from a single telescope
to a retroreflector (mirror) target, which is usually set
up at a range of 100 to 500 meters. The returned light
signal is received by the single telescope and directed
to a detector. The light is absorbed by the molecules
in the beam path as it propagates to the mirror and
absorbed further as it is reflected back to the ana
lyzer. One advantage of OP-FTIR monitoring is that
the concentrations of a multitude of infrared absorb-
ing gaseous chemicals can be detected and measured
simultaneously with high temporal resolution. Figure
1-4 shows a picture of the OP-FTIR instrument/
scanner used in the current study.
Figure 1-4. OP-FTIR Instrument/Scanner.
The OP-TDLAS system (Unisearch Associates) is a
fast, interference-free technique for making continu-
ous concentration measurements of many gases. The
OP-TDLAS used in the current assessment is capable
of measuring concentrations in the range of tens of
parts per billion over an open path up to 1 km, for
gases such as carbon monoxide, carbo dioxide,
ammonia, and methane. The laser emits radiation at
a particular wavelength when an electrical current is
passed through it. The light wavelength depends on
the current and therefore allows scanning over an
absorption feature and analyzing for the target gas
concentration, using Beer's law. The OP-TDLAS
used in this study is a multiple channel TDL instru-
ment that allows fast scanning electronically (few
seconds) among many beam-paths (presently, 8
beams). The OP-TDLAS applies a small 4-inch
telescope, which launches the laser beam to a mirror.
The laser beam is returned by the mirror to the
telescope, which is connected with fiber optics to a
control box that houses the laser and a multiple
channel detection device. For this particular field
campaign, data from the OP-TDLAS were used to
provide additional information on methane concentra-
tions at the site. At the time of the field campaign, the
OP-TDLAS system had only recently been acquired
by EPA. Consequently, standard operating and
1-3
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Evaluation of Fugitive Emissions at a
calibration procedures were still being developed.
Table 1-1 presents summary information on the ORS
instrumentation used in this study. The table lists the
compounds measured by each instrument during the
current study, and instrument limitations such as
weather and interfering species.
Table 1-1. Summary Information on the ORS
Instrumentation Used in the Study
Parameter
OP-FTIR
OP TOLAS
Wavelength range
Target analysis
Detection limit
Limiting weather
conditions
Infrared (2-20
Urn)
Methane, ammo-
nia, gasoline,
other VOCs
Parts per billion
Heavy rain
Near Infrared
(-1.5 urn)
Methane
Parts per billion
Heavy rain, fog
Interfering species
carbon dioxide.
water
None
Meteorological and survey measurements were also
made during the field campaign. A theodolite was
used to make the survey measurement of the azimuth
and elevation angles and the radial distances to the
mirrors relative to the OP-FTIR sensor.
1.2.1 Horizontal RPM
The HRPM provides spatial information to path-
integrated measurements acquired in a horizontal
plane by an ORS system. This technique yields
information on the two-dimensional distribution of
the concentrations in the form of chemical-
concentration contour maps. This form of output
readily identifies the location of higher chemical
emissions, or "hot spots." This method can be of
great benefit for performing site surveys before,
during, and after site remediation activities. In this
particular study, this method is useful for identifying
areas where the landfill gas collection control system
may not be functioning properly. These areas are the
major source of emissions from the site.
HRPM scanning is usually performed with the ORS
beams located as close to the ground as is practical.
This enhances the ability to detect minor constituents
emitted from the ground, since the emitted plumes
dilute significantly at higher elevations.
The survey area is typically divided into a Cartesian
grid of n times m rectangular cells. In some unique
cases, the survey area may not be rectangular due to
obstructions, and the shape of the cells may be
slightly altered accordingly. A mirror is located in
each of these cells, and the ORS sensor scans to each
of these mirrors, dwelling on each for a set measure-
ment time (30 seconds in the present assessment).
The system scans to the mirrors in the order of either
increasing or decreasing azimuth angle. The path-
integrated concentrations (PIC) measured at each
mirror are averaged over several scanning cycles to
produce time-averaged concentration maps. Meteoro-
logical measurements are made concurrent to the
scanning measurements.
Figure 1-5 represents a typical HRPM configuration.
In this particular case, n = m = 3. The solid lines
represent the nine optical paths, each terminating at
a mirror.
150
E. 100
0)
u
c
s
Ol
u
50
(A
'x
OP-FTIR
\
x Axis
-50 0 50 100
Typical x Distance (meters)
150
Figure 1-5. Example of a HRPM Configuration.
1-4
-------
Former Landfill in Colorado Springs, Colorado
One OP-FTIR instrument (manufactured by Uni-
search Associates) was used to collect HRPM data
during the field campaign.
1.2.2 Vertical RPM
The VRPM method maps the concentrations in the
vertical plane by scanning the ORS system in a
vertical plane downwind from an area source. One
can obtain the plane-integrated concentration from
the reconstructed concentration maps. The flux is
calculated by multiplying the plane-integrated con-
centration by the wind speed component perpendicu-
lar to the vertical plane. Thus, the VRPM method
leads to a direct measurement-based determination of
the upwind source emission rate (Hashmonay et al.,
1998; Hashmonay and Yost, 1999, Hashmonay et al.,
2001).
Figure 1-6 shows a schematic of the experimental
setup used for vertical scanning. Several mirrors were
placed in various locations on a vertical plane in-line
with the scanning OP-FTIR. A vertical platform
(scissors jack) was used to place two of the mirrors at
a predetermined height above the surface. The loca-
tion of the vertical plane is selected so that it inter-
sects the mean wind direction as close to perpendicu-
lar as practical. One OP-FTIR instrument (manufac-
tured by EVIACC, Inc.) was used to complete the
VRPM survey.
1.3 Quality Objectives and Criteria
Data quality objectives (DQOs) are qualitative and
quantitative statements developed using EPA's DQO
Process (U.S. EPA QA/G-4, 2000) that clarify study
objectives, define the appropriate type of data, and
specify tolerable levels of potential decision errors
that will be used as the basis for establishing the
quality and quantity of data.
Quantitative objectives are established for critical
measurements using the data quality indicators
(DQIs) of accuracy, precision, and completeness. The
acceptance criteria for these DQIs are summarized
later in Table 5-2 of Section 5 of this report. Accu-
racy of measurement parameters is determined by
Fugitive Source/
Area of Interest
PI-ORS
Instrument
Figure 1-6. Example of a VRPM Configuration.
comparing a measured value to a known standard,
assessed in terms of percent bias. Values must be
within the listed tolerance to be considered accept-
able.
Precision is evaluated by making replicate measure-
ments of the same parameter and assessing the
variations of the results. Precision is assessed in
terms of relative percent difference (RPD) or relative
standard deviation (RSD). Replicate measurements
are expected to fall within the tolerances shown later
in Table 5-2. Completeness is expressed as a percent-
age of the number of valid measurements compared
to the total number of measurements taken.
Estimated minimum detection limits of the OP-FTIR
instrument, by compound, are given in Table 1-2. It
is important to note that the values listed in Table 1-2
should be considered first step approximations, as the
minimum detection limit is highly variable and
depends on many factors including atmospheric
conditions. Actual minimum detection levels are
1-5
-------
Evaluation of Fugitive Emissions at a
Table 1-2. Detection Limits for Target Compounds.
Compound
OP-FTIR Estimated Detection
Limit for Path Length = 100m,
1 min Average
(ppmv)
AP-42 Value ratioed to an
average methane concentra-
tion of 50 ppma
(ppmv)
1 ,4-Dichlorobenzene
2-Propanol
Acetone
Acrylonitrile
Butane
Chlorobenzene
Chloroform
Chloromethane
Dichlorodifluoromethane
Dimethyl sulfide
Ethane
Ethanol
Ethyl benzene
Ethyl chloride
Ethylene dibromide
Ethylene dichloride
Fluorotrichloromethane
Hexane
Hydrogen sulfide
Methane
Methanol
Methyl ethyl ketone
Methyl isobutyl ketone
Methyl mercaptan
Methylene chloride
Octane
Pentane
Propane
Propylene dichloride
Tetrachloroethene
Trichlorethylene
Vinyl chloride
Vinylidene chloride
Xylenes
0.012
0.0060
0.024
0.010
0.0060
0.040
0.012
0.012
0.0040
0.018
0.010
0.0060
0.060
0.0040
0.0060
0.030
0.0040
0.0060
6.0
0.024
0.0015
0.030
0.040
0.060
0.014
0.0025
0.0080
0.0080
0.014
0.0040
0.0040
0.010
0.014
0.030
0.000021
0.0050
0.00070
0.00063
0.00050
0.000025
0.0000030
0.00010
0.0016
0.00078
0.089
0.0027
0.00046
0.00013
0.00000010
0.000041
0.000076
0.00066
0.0036
N/Ab
N/A
0.00071
0.00019
0.00025
0.0014
N/A
0.00033
0.0011
0.000018
0.00037
0.00028
0.00073
0.000020
0.0012
a The AP-42 values represent an average concentration of different pollutants in the raw landfill gas. This is not comparable
to the detection limits for the OP-FTIR which is an average value for a path length of 100 meters across the surface of the
area source being evaluated. However, it does provide an indication of the types of pollutants and range of concentrations
associated with landfill gas emissions in comparison to the detection limits of the OP-FTIR.
b N/A = not available.
1-6
-------
Former Landfill in Colorado Springs, Colorado
calculated in the quantification software for all a known concentration of the target compound.
measurements taken. Minimum detection levels for
each absorbance spectrum are determined by calcu- 1.4 PrOJGCt SchGdulG
lating the root mean square (RMS) absorbance noise The field campaign was completed for this study
in the spectral region of the target absorption feature. during September 2003. Table 1-3 provides the
The minimum detection level is the absorbance signal schedule of ORS work that was performed.
(of the target compound) that is five times the RMS
noise level, using a reference spectrum acquired for
Table 1-3. Schedule of Work Performed at the Site.
Day Detail of Work Performed
Tuesday, September 9 Travel to site
AM—HRPM survey of NW quadrant
Wednesday, September 10
PM—HRPM survey of SW quadrant
AM—HRPM survey of NE quadrant
Thursday, September 11
PM—HRPM survey of SE quadrant
Friday, September 12 VRPM survey of site
Saturday, September 13 Travel from site
1-7
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Evaluation of Fugitive Emissions at a
-------
Former Landfill in Colorado Springs, Colorado
Chapter 2
Testing Procedures
The following subsections describe the testing proce-
dures used at the site. The site was divided into
quadrants designated as Northeast, Northwest,
Southeast, and Southwest. HRPM was performed in
each of the quadrants to produce surface concentra-
tion maps and to locate any emissions hot spots.
VRPM was performed on the northern border of the
site. The coordinates of the mirrors used in each
configuration relative to the position of the OP-FTIR
instrument are presented in Appendix A.
The site contained several passive vents located
approximately 2 m above the surface. These vents
were sealed during the HRPM surveys of the surface
(see Figure 2-1). The rational for sealing the vents
was that they were suspected emissions hot spots, and
may have masked other emissions hot spots located
along the surface of the site. The seals were removed
from the vents for the VRPM survey.
OP-FTIR data were collected as interferograms and
archived to CD-ROMs. After archiving, the interfero-
grams were transferred to ARC ADIS. They were then
transformed to absorbance spectra, and concentra-
tions were calculated using Non-Lin (Spectrosoft)
quantification software. This analysis was done after
completion of the field campaign. Concentration data
were then matched with the appropriate mirror
locations, wind speed, and wind direction. The
ARCADIS RPM software was used to process the
data into horizontal plane concentration maps or
vertical plane plume visualizations, as appropriate.
Meteorological data including wind direction, wind
speed, temperature, relative humidity, and barometric
pressure were continuously collected during the
measurement campaign with a Climatronics model
Figure 2-1. Passive Vent Sealed During the
HRPM Surveys.
101990-G1 instrument. The Climatronics instrument
is automated. It collects real-time data from its
sensors and records time-stamped one-minute aver-
ages to the data collection computer. Wind direction
and speed sensing heads were used to collect data at
the surface during the HRPM surveys and at heights
of 2 and 10m during the VRPM survey (the 10m
2-1
-------
Evaluation of Fugitive Emissions at a
sensor was placed on top of the scissors jack). The
sensing heads for wind direction incorporate an
auto-north function (automatically adjusts to mag-
netic north) that eliminates the errors associated with
subjective field alignment to a compass heading.
After collection, a linear interpolation between the
two sets of data is done to estimate wind velocity as
a function of height.
Once the concentrations maps and wind information
were processed, the concentration values were inte-
grated, incorporating the wind speed component
normal to the plane at each height level to compute
the flux through the vertical plane. In this stage, the
concentration values were integrated from parts per
million by volume to grams per cubic meter, consid-
ering the molecular weight of the target gas and
ambient temperature. This enables the flux to be
calculated directly in grams per second using wind
speed data in meters per second.
The concordance correlation factor (CCF) is used to
measure the reproducibility of a reference measure-
ment to another measurement. In the RPM methodol-
ogies, it is used to represent the level of fit for the
reconstruction in the path-integrated domain (pre-
dicted vs observed PIC). The CCF is similar to the
Pearson correlation coefficient (r) but is adjusted to
account for shifts in location and scale. Like the
Pearson correlation, CCF values are bounded be-
tween -1 and 1, yet the CCF can never exceed the
absolute value of the Pearson correlation factor. For
example, the CCF will be equal to the Pearson
correlation when the linear regression line intercepts
the ordinate at 0, and its slope equals 1. Its absolute
value will be lower than the Pearson correlation when
the above conditions are not met. For the purposes of
this report, the closer the CCF value is to 1, the better
the fit for the reconstruction in the path-integrated
domain.
A moving average is used in the calculation of the
average flux values to show temporal variability in
the measurements. A moving average involves
averaging flux values calculated from several consec-
utive cycles (a cycle is defined as data collected when
scanning one time through all the mirrors in the
configuration). For example, a data set taken from 5
cycles may be reported using a moving average of 4,
where values from cycles 1 to 4, and 2 to 5 are
averaged together to show any variability in the flux
values.
The shape of the plume maps generated by this meth-
od are used to give information on the homogeneity
of the plume and do not affect the calculated flux
values. The shape of the maps generated represents
the best fit of the limited data to a symmetric Gaussi-
an function, and this fit may drive the plume shape
outside of the measurement configuration.
2.1 HRPM Measurements
The variation in terrain at the site resulted in a unique
geometry and measurement configuration for each
quadrant.
2.1.1 Northwest Quadrant
The Northwest quadrant was bounded on the north
and west side by a slope, on the east by the Northeast
quadrant, and on the south by the Southwest quad-
rant. Figure 2-2 is a schematic of the HRPM configu-
ration used in the Northwest quadrant. The solid red
lines represent the nine optical paths used in the
configuration, each terminating at a mirror.
so
x Distance, m
Figure 2-2. Schematic of the HRPM Config-
uration Used in the Northwest Quadrant.
2-2
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Former Landfill in Colorado Springs, Colorado
2.1.2 Southwest Quadrant
The Southwest quadrant was bounded on the west
and south sides by a slope, on the east by the South-
east quadrant, and on the north by the Northwest
quadrant. Figure 2-3 is a schematic of the HRPM
configuration used in the Southwest quadrant. Due to
the shape of the quadrant, the configuration consisted
of only seven optical paths.
150
x Distance, m
Figure 2-3. Schematic of the HRPM Config-
uration Used in the Southwest Quadrant.
2.1.3 Northeast Quadrant
Figure 2-4 presents a schematic of the FtRPM config-
uration used in the Northeast quadrant. The Northeast
150
£ 100
x Distance, m
Figure 2-4. Schematic of the HRPM config-
uration used in the northeast quadrant.
quadrant was bounded on the east and north sides by
a slope, on the south by the Southeast quadrant, and
on the west by the Northwest quadrant. Due to the
size and shape of the quadrant, the configuration
consisted of only six optical paths.
2.1.4 Southeast Quadrant
The Southeast quadrant was bounded on the east and
south sides by a slope, on the west by the Southwest
quadrant, and on the north by the Northeast quadrant.
Figure 2-5 presents a schematic of the FtRPM config-
uration used in the Southeast quadrant. Due to the
size and shape of the quadrant, the configuration
consisted of only five optical paths.
50 100
x Distance, m
Figure 2-5. Schematic of the HRPM Config-
uration Used in the Southeast Quadrant.
2.2 VRPM Measurements
A VRPM survey was conducted along the northern
border of the site (see Figure 1-3). The VRPM
configuration consisted of one mirror placed on the
ground between the OP-FTIR and the scissors jack,
one mirror placed at the base of the scissors jack, two
mirrors placed on the scissors jack, and one mirror
placed on the ground beyond the scissors jack.
2.3 OP-TDLAS Measurements
The OP-TDLAS system was deployed for two days
of the field campaign to provide additional informa-
2-3
-------
Evaluation of Fugitive Emissions at a
tion on methane concentrations at the site. Figure 2-6
is a picture of the OP-TDLAS system. The OP-
TDLAS collected data along the surface of the site on
September 10. On September 11, the instrument was
set up on a slope adj acent to the southern boundary of
the site, where a large amount of erosion was ob-
served. Figures 2-7 and 2-8 present a schematic of the
OP-TDLAS configurations used on September 10
and 11, respectively. The distance of the path lengths
used in each OP-TDLAS configuration are presented
in Appendix B of this report.
Figure 2-7. Schematic of the OP-TDLAS
Configuration Used on September 10.
Figure 2-6. OP-TDLAS System.
Figure 2-8. Schematic of OP-TDLAS
Configuration Used on September 11.
2-4
-------
Former Landfill in Colorado Springs, Colorado
Chapter 3
Results and Discussion
The results from the ORS data collected at the site are
presented in the following subsections. It should be
noted that the concentration values reported in the
following sections have not been corrected to stan-
dard atmospheric conditions. The measured methane
concentrations from the HRPM and VRPM surveys
are presented in Appendix C.
3.1 The Horizontal RPM Results
Figure 3-1 presents the average surface methane
concentration contour map of the entire site. The
contours give methane concentration values (in parts
per million) above an ambient background concentra-
tion of 1.55 ppm, which was the lowest methane
concentration measured during the field campaign.
The determination of this map is based on the mean
path-integrated methane concentration measurements
collected with the Unisearch OP-FTIR instrument in
the four quadrants, along 27 beam paths. The red X' s
show the location of the 27 mirrors used in the
VRPM OP-FTIR/Scanner
Configuration /
X
Hot Spot
B
Figure 3-1. Average Surface Methane Concentration Contour Map of
the Colorado Springs Landfill.
3-1
-------
Evaluation of Fugitive Emissions at a
HRPM surveys, and the red dot shows the location of
the OP-FTIR/scanner used in the HRPM surveys. The
location of the VRPM survey is also shown in the
figure. The blue dot indicates the location of the
OP-FTIR/scanner used in the VRPM survey. The
figure shows the presence of a hot spot in the North-
east quadrant (denoted as hot spot "A" in Figure 3-1,
with concentrations greater than 0.4 ppm above
ambient background), and the Southeast quadrant
(denoted as hot spot "B" in Figure 3-1, with concen-
trations greater than 0.5 ppm above ambient back-
ground).
As mentioned previously, the VRPM configuration
was located along the northern boundary of the site.
Table 3-1 presents methane emission flux determina-
tions from the downwind VRPM survey. Figure 3-2
presents the reconstructed methane plume from the
VRPM survey of the site. Contour lines give methane
concentrations (in ppm) above an ambient back-
ground concentration of 1.55 ppm. The average
calculated methane flux from the site was 4.9 g/s.
Even though the observed wind direction was nearly
perpendicular to the VRPM configuration, this value
may be an underestimation of the actual emission rate
from the site.
Table 3-1. Moving Average of Calculated Methane
Flux, CCF, Wind Speed, and Wind Direction from
the VRPM Survey.
Mean
Std. Dev.
0.931
0.0206
Cycles
Ito4
2 to 5
3 to 6
4 to 7
5 to 8
6 to 9
7 to 10
8 to 11
9 to 12
CCF
0.959
0.960
0.930
0.932
0.930
0.914
0.893
0.934
0.926
Flux,
g/s
5.7
5.8
5.3
4.3
4.3
3.9
5.0
6.1
5.4
Wind
Speed,
m/s
4.9
4.9
4.7
4.9
4.8
5.0
4.9
4.5
4.4
Direction",
deg
15
14
17
17
20
19
14
12
5
a Wind direction is measured from a vector normal to the plane of
the measurement configuration.
Figure 3-2 shows that the methane plume detected
during the VRPM survey was centered near the
location of the OP-FTIR/scanner (crosswind distance
between 0 and 100 meters) indicating that most of the
emissions originated from the eastern portion of the
site. Based on an analysis of the HRPM data pre-
sented in Figure 3-1 and wind data collected during
the VRPM survey, it is likely that the emissions from
hot spot "A" were completely captured by the VRPM
configuration. However, a portion of the emissions
from hot spot "B" (the most intense hot spot detected
during the HRPM survey) were probably not captured
by the VRPM configuration. Consequently, the
calculated methane flux may be underestimating the
actual emission rate from the site by as much as a
factor of two.
The methane concentrations measured during the
VRPM survey (peak concentrations of greater than
2.25 ppm above ambient background) are higher than
the surface methane concentrations measured during
the HRPM surveys (peak concentration of greater
than 0.5 ppm above ambient background). This is
probably due to the fact that the passive vents at the
site were sealed during the HRPM surveys, but were
not sealed during the VRPM survey.
Figure 3-3 presents a time series of calculated meth-
ane fluxes and the observed wind direction (from
normal to the configuration). The figure shows that
the largest methane flux values occurred when the
winds were close to perpendicular to the VRPM
configuration.
All data sets from the HRPM and VRPM surveys
were searched for the presence of VOCs and ammo-
nia. The analysis detected the presence of gasoline
(primarily octane) during the HRPM survey of the
Northeast quadrant. However, this is attributed to
emissions from the gasoline generators used in the
3-2
-------
Former Landfill in Colorado Springs, Colorado
16
14
12
E 10
«
V
Concentrations are in ppm above ambient
Flux = 4.9 g/s
Mirror
50
250
100 150 200
Crosswind Distance, m
Figure 3-2. Average Reconstructed Methane Plume from the VRPM Survey.
field campaign, which were located upwind of the measurement configuration during the HRPM survey
X
il 4
Q)
s
I— — Methane Flux I
| Wind Direction
\
iis
25
20
I
O)
*
8
10
I
6
123456789
Cycle Number
Figure 3-3. Methane Flux and Prevailing Wind Direction
Measured During the VRPM Survey.
0
a
I
3-3
-------
Evaluation of Fugitive Emissions at a
of the Northeast quadrant. The measured gasoline
concentrations ranged from below detection level to
23 ppb.
Analysis of the other data sets did not reveal VOCs or
ammonia atlevels higher than the minimum detection
level (MDL) of the OP-FTIR instruments. Table 3-2
concentrations measured with the OP-TDLAS system
agree fairly well with the levels found in hot spots
identified during the HRPM surveys.
Table 3-3. Average Methane Concentrations
above Ambient Background Levels Measured
with the OP-TDLAS System.
OP-FTIR for this field campaign.
Table 3-2 MiP'm"m n*»t*»rtinn 1 m/c*lc hw Pnm-
pound for the
Compound
Ammonia
Benzene
Ethanol
Gasoline
Methanol
Toluene
m-Xylene
o-Xylene
p-Xylene
OP-FTIR Instrument.
Average MDL,
ppb
8.4
140
27
13
17
67
45
49
59
Range,
ppb
3. 6 to 20
75 to 280
12 to 65
6.3 to 37
7.2 to 41
32 to 180
22 to 120
25 to 120
28 to 160
3.4 OP-TDLAS Results
Q c\7ct<^m m£»aciir£»rl m£
Beam
Path
-1. tlHl
1
2
7
8
Average
Std. Dev.
Average
Std. Dev.
Average
Std. Dev.
Average
Std. Dev.
Average
Std. Dev.
Average
Std. Dev.
Average
Std. Dev.
Average
Std. Dev.
Survey of
Surface
9/10/03
0.53
0.05
0.51
0.05
0.52
0.03
0.51
0.01
0.51
0.05
0.51
0.02
0.47
0.02
0.49
0.02
Survey of
Slope
9/11/03
0.74
0.13
1.07
0.16
0.78
0.15
0.55
0.12
0.89
0.27
0.55
0.20
1.34
0.33
0.47
0.22
trations along the surface and on the slope adj acent to
the southern boundary of the site. Table 3-3 presents
the average methane concentrations (in parts per
million above an ambient background level of 1.55
ppm) measured at the site by the OP-TDLAS system.
Refer to Figures 2-7 and 2-8 for the location of the
beam paths used in each survey.
The survey of the surface found average methane
concentrations between 0.47 and 0.53 ppm above
ambient background levels. The surface methane
The survey of the slope along the southern boundary
of the site found relatively higher methane concentra-
tions. The largest average methane concentrations
were detected along beam path #2 (1.07 ppm above
ambient background) and beam path #7 (1.34 ppm
above ambient background). The relatively larger
standard deviations found during the survey of the
slope suggest that methane hot spots were present
along the slope.
3-4
-------
Former Landfill in Colorado Springs, Colorado
Chapter 4
Conclusion
This report presents the results from a field campaign
conducted in September 2003 at a former landfill site
in Colorado Springs, Colorado. The study used
measurements from ground-based ORS instruments
and the ORS-RPM method to characterize fugitive
emissions of methane and VOCs from the site.
HRPM surveys of the site detected the presence of
two methane hot spots located along the eastern side
of the site. The first methane hot spot, located in the
Northeast quadrant, had concentrations greater than
0.4 ppm above an ambient background concentration
of 1.55 ppm. The other hot spot was located in the
Southeast quadrant and had concentrations greater
than 0.5 ppm above ambient background levels.
The HRPM survey of the Northeast quadrant detected
the presence of gasoline at concentrations ranging
from below detection level to 23 ppb. This was
attributed to the field operations based on analysis of
the observed wind. The data sets from the HRPM and
VRPM surveys were searched for the presence of
VOCs and ammonia. Analysis did not detect VOCs
or ammonia at levels higher than the minimum
detection level (MDL) of the OP-FTIR instruments.
The VRPM configuration was set up along the
northern boundary of the site. The calculated methane
flux from the site was 4.9 g/s. The peak of the meth-
ane plume measured during the VRPM survey was
located close to the location of the OP-FTIR/scanner.
This agrees well with the location of the methane hot
spots detected during the HRPM survey, indicating
that the hot spots may be a major source of the
methane plume detected during the VRPM survey.
The OP-TDLAS system collected information on
methane concentrations along the surface of the site
and on a slope adjacent to the southern boundary of
the site. The survey of the surface found average
methane concentrations between 0.47 ppm and 0.53
ppm above ambient background levels. These values
agree fairly well with the methane levels found in hot
spots identified during the HRPM surveys.
The survey of the slope along the southern boundary
of the site found slightly elevated methane concentra-
tions. The largest average measured methane concen-
tration was 1.34 ppm above ambient background
levels. The relatively larger standard deviations found
during the slope survey suggest that methane hot
spots were present along the slope.
The schedule of the field campaign allowed for only
three days of data collection. HRPM data was col-
lected during the first two days of the campaign, and
VRPM data was collected during the last day. Due to
a change in prevailing wind direction during the last
day of the campaign, the VRPM configuration had to
be relocated. Consequently, only about one hour
worth of VRPM data was collected. For future
campaigns, it is recommended that more time be
allocated for VRPM data collection to ensure that a
larger data set is obtained. This would provide more
information on flux variations from the site due to
differing weather conditions.
The site contained several passive vents located
approximately 2 meters above the surface. These
vents were sealed during the HRPM surveys because
they were suspected emissions hot spots, and may
have masked other emissions hot spots located along
the surface of the site. The seals were removed from
the vents for the VRPM survey. This may not have
4-1
-------
Evaluation of Fugitive Emissions at a
been the best approach for characterizing the surface method with alternate configurations may be war-
emissions from this site. ranted in order to get a more definitive methane flux
value, and to address the issues above.
Future monitoring of this site using the ORS-RPM
4-2
-------
Former Landfill in Colorado Springs, Colorado
Chapter 5
Quality Assurance/Quality Control
As stated in the ECPD Optical Remote Sensing
Facility Manual (U.S. EPA, 2004), all equipment is
calibrated annually or cal-checked as part of standard
operating procedures. Certificates of calibration are
kept on file. Maintenance records are kept for any
equipment adjustments or repairs in bound project
notebooks that include the data and description of
maintenance performed. Instrument calibration
procedures and frequency are listed in Table 5-1 and
further described in the text.
As part of the preparation for this project, a Category
III Quality Assurance Project Plan (QAPP) was
prepared and approved for each separate field cam-
paign. In addition, standard operating procedures
were in place during the field campaign.
The critical measurements associated with this
project and the established data quality indicator
(DQI) goals in terms of accuracy, precision, and
completeness are listed in Table 5-2. More informa-
tion on the procedures used to assess DQI goals can
be found in Section 10 of the ECPD Optical Remote
Sensing Facility Manual (U.S. EPA, 2004).
5.2.1 DQI Check for Analyte PIC Measure-
ment
The precision and accuracy of the analyte path-
integrated concentration (PIC) measurements was
assessed by analyzing the measured nitrous oxide
concentrations in the atmosphere. A typical back-
ground atmospheric concentration for nitrous oxide
is about 315 ppb. However, this value may fluctuate
Table 5-1. Instrumentation Calibration Frequency and Description.
Instrument Measurement Calibration Date
Calibration Detail
Climatronics Model Wind speed in miles 22 April 2003
101990-G1 Meteorological per hour
Heads
Climatronics Model Wind direction in 22 April 2003
101990-G1 Meteorological degrees from north
Heads
Topcon Model GTS-21 ID Distance 1 May 2003
Theodolite
Topcon Model GTS-21 ID Angle 21 May 2003
Theodolite
APPCD Metrology Lab cal. records
on file
APPCD Metrology Lab cal. records
on file
Actual distance = 50 ft
Measured distance = 50.6 and 50.5
ft
Actual angle = 360°
Measured angle = 359° 41' 18" and
359°59'55"
5-1
-------
Evaluation of Fugitive Emissions at a
Table 5-2. DQI Goals for Instrumentation.
Analysis Method
Measurement
Parameter
Accuracy
Precision
Detection
Limit
Completeness
See Table 1-1 90%
N/A 90%
AnalytePIC OP-FTIR: nitrous oxide ±25%, ±15%, ±10%a ±10%
concentrations
Ambient Wind Climatronics met heads side- ±1 m/s ±1 m/s
Speed by-side comparison in the
field
Ambient Wind Climatronics met heads side- ±10° ±10° N/A 90%
Direction by-side comparison in the
field
Distance Topcon Theodolite ±1 m ±1 m O.lm 100%
Measurement
a The accuracy acceptance criterion of ±25% is for pathlengths of less than 50 m, ±15% is for pathlengths between 50 and 100 m, and ±10%
is for pathlengths greater than 100 m.
due to seasonal variations in nitrous oxide concentra-
tions or elevation of the site. The elevation of the site
surveyed in this field campaign is approximately
6,000 ft above sea level. At this elevation, the optical
density of a nitrous oxide concentration of 315 ppb
would be equivalent to a lower concentration of
nitrous oxide at sea level, due to the decreased air
density. To correct the background nitrous oxide
level for the effects of elevation, the measured
temperature and atmospheric pressure were ratioed to
standard temperature and pressure values. The
corrected background nitrous oxide concentration for
this site is approximately 249 ppb.
The precision of the analyte PIC measurements was
evaluated by calculating the relative standard devia-
tion of each data subset. A subset is defined as the
data collected along one particular path length during
one particular survey in one survey sub-area. The
number of data points in a data subset depends on the
number of cycles used in a particular survey.
The accuracy of the analyte PIC measurements was
evaluated by comparing the calculated nitrous oxide
concentrations from each data subsets to the cor-
rected background concentration of 249 ppb. The
number of calculated nitrous oxide concentrations
that failed to meet the DQI accuracy criterion in each
data subset was recorded.
Overall, 39 data subsets were analyzed from this field
campaign. Based on the DQI criterion set forth for
precision of ±10%, each of the 39 data subsets were
found to be acceptable. The range of calculated
relative standard deviations for the data subsets from
this field campaign was 0.54 to 6.9 ppbm, which
represents 0.22 to 2.8% RSD.
Each data point (calculated nitrous oxide concentra-
tion) in the 39 data subsets were analyzed to assess
whether or not it met the DQI criterion for accuracy
of ±25% (249 ± 62 ppb) for path lengths less than 50
meters, ±15% (249 ±37 ppb) for path lengths be-
tween 50 and 100 meters, and ±10% (249 ± 25 ppb)
for path lengths greater than 100 meters. A total of
646 data points were analyzed, and all met the DQI
criteria for accuracy. Based on the DQI criterion set
forth for accuracy and precision, all data points were
found to be acceptable, for a total completeness of
100%.
5.2.2 DQI Checks for Ambient Wind Speed
and Wind Direction Measurements
Section 10 of the ECPD Optical Remote Sensing
5-2
-------
Former Landfill in Colorado Springs, Colorado
Facility Manual (U. S. EPA, 2004) states that the DQI
goals for precision and accuracy of the Climatronics
meteorological heads are assessed by collecting
meteorological data for 10 minutes with the two
heads set up side-by side. This was not done prior to
the current field campaign because this DQI proce-
dure had not been implemented at the time of the
study. However, the Climatronics heads were cali-
brated in April 2003 by the APPCD Metrology Lab
(see Table 5-1). Additionally, checks for agreement
of the wind speed and wind direction measured from
the two heads (2 m and 10m) were done in the field
during data collection. Although it is true that some
variability in the parameters measured at both levels
should be expected, this is a good first-step check for
assessing the performance of the instruments. An-
other check is done in the field by comparing the
measured wind direction to the forecasted wind
direction for that particular day.
5.2.3 DQI Check for Precision and Accuracy
of Theodolite Measurements
Although calibration of this instrument did not occur
immediately prior to this field campaign, the theodo-
lite was originally calibrated by the manufacturer
prior to being received by the U.S. EPA. Addition-
ally, there are several internal checks in the theodolite
software that prevent data collection from occurring
if the instrument is not properly aligned on the object
being measured or if the instrument has not been
balanced correctly. When this occurs, it is necessary
to re-initialize the instrument to collect data.
Prior to this field campaign, DQI checks were per-
formed on the theodolite during May 2003 at a field
site near Chapel Hill, NC. The calibration of distance
measurement was done using a tape measure to
compare the actual distance to the measured distance.
This check was duplicated to test the precision of this
measurement. The actual distance measured was 15.2
m. The measured distance during the first test was
15.4 m, and the measured distance during the second
test was 15.4 m. The results indicate the accuracy
(1.3% bias for test one and two) and precision (0%
RSD) of the distance measurement fell well within
the DQI goals.
The check to test the precision and accuracy of the
angle measurement was done by placing two mirror
targets approximately 180 degrees apart. The theodo-
lite was placed in the middle of the imaginary circle
formed by the two mirrors. Thus, the actual angle was
360°. The angle measured during the first test was
359° 41' 18", and the angle measured during the
second test was 3 5 9° 59' 55". The results indicate the
accuracy and precision of the angle measurement fall
well within the DQI goals.
Several checks should be performed on the OP-FTIR
instrumentation prior to deployment to the field and
during the duration of the field campaign. More
information on these checks can be found in MOP
6802 and 6807 of the ECPD Optical Remote Sensing
Facility Manual. At the time of the current field
campaign, the procedures and schedule of QC checks
were still being developed. Consequently, QC checks
were performed only in the field on the Unisearch
OP-FTIR.
On the first day of the field campaign (September
10), the single beam ratio, signal-to-noise, baseline
stability, electronic noise, saturation, and random
baseline noise tests were performed on the Unisearch
OP-FTIR. The results of the tests indicated that the
instrument was operating within the acceptable
criteria range.
On September 11, the signal-to-noise, and single
beam ratio tests were performed on the Unisearch
OP-FTIR. The results of these tests indicated that the
instrument was operating within the acceptable
criteria range.
In addition to the QC checks performed on the
OP-FTIR, the quality of the instrument signal
(interferogram) was checked constantly during the
field campaign. This was done by ensuring that the
intensity of the signal is at least 5 times the intensity
of the stray light signal (the stray light signal is
collected as background data prior to actual data
5-3
-------
Evaluation of Fugitive Emissions at a
collection and measures internal stray light from the
instrument itself). In addition to checking the strength
of the signal, checks were done constantly in the field
to ensure that the data were being collected and
stored to the data collection computer. During the
campaign, a member of the field team constantly
monitored the data collection computer to make sure
these checks were completed.
5.4 Validation of Concentration Data
Collected with the OP-FTIR
During the analysis of the OP-FTIR data, a validation
procedure was performed to aid in identifying the
presence of gasoline in the dataset. This validation
procedure involves visually comparing an example of
the measured spectra to a laboratory-measured
reference spectrum.
Figure 3-4 shows an example of a validation done
using a spectrum collected during the HRPM survey
of the Northeast quadrant. Gasoline was detected in
this particular spectrum. The gasoline features can be
seen in the measured field spectrum (green trace).
Classical Least Squares (CLS) analysis performed on
Figure 3-4. Comparison of a spectrum
Measured at the Site (green trace) to Reference
Spectra of Gasoline (red trace).
this spectrum resulted in determinations of 22.0 ± 6.5
ppb of gasoline. The uncertainty value is equal to
three times the standard error in the regression fit of
the measured spectrum to a calibrated reference
spectrum.
5.5 Internal Audit of Data Input Files
An internal audit was performed by the ARCADIS
Field Team Leader on a sample of approximately
10% of the data from the field campaign. The audit
investigated the accuracy of the input files used in
running the RPM programs. The input files contain
analyzed concentration data, mirror path lengths, and
wind data. The results of this audit found no prob-
lems with the accuracy of the input files created.
5.6 OP-TDLAS Instrument
At the time of the field campaign, the OP-TDLAS
system had only recently been acquired by EPA.
Consequently, standard operating and calibration
procedures were still being developed. Many im-
provements have been made to the Q A procedures for
this instrument since this field campaign. Some of
these improvements include the development of
calibration cells, and the development of a standard
operating procedure for collecting emissions mea-
surements with the OP-TDLAS (see MOP 6811 of
the ECPD Optical Remote Sensing Facility Manual).
The results of the current field campaign present
methane concentrations measured with the OP-FTIR
instrument and the OP-TDLAS system. In order to
evaluate the comparability of measurements from the
two instruments, an experiment was done in January
2004 to compare methane concentrations measured
with the OP-TDLAS system and the IMACC
OP-FTIR. Figure 3-5 shows the results of this experi-
ment. The results show that methane concentrations
measured with the OP-TDLAS were slightly higher
(3%) than concentrations measured with the OP-
FTIR instrument.
5-4
-------
Former Landfill in Colorado Springs, Colorado
5000
4500
1000 2000 3000 4000
FUR-Measured PlC(ppn-m)
5000
Figure 5-2.Post-Colorado Springs Comparison
of Methane Concentrations Measured with the
OP-TDLAS and OP-FTIR Instruments.
5-5
-------
Evaluation of Fugitive Emissions at a
5-6
-------
Former Landfill in Colorado Springs, Colorado
Chapter 6
List of References
Hashmonay, R.A., M.G. Yost, D.B. Harris, and E.L. Thompson (1998), Simulation study for gaseous fluxes
from an area source using computed tomography and optical remote sensing, presented at SPIE Conference
on Environmental Monitoring and Remediation Technologies, Boston, MA, Nov., 1998, in SPIE Vol. 3534,
pp. 405-410.
Hashmonay, R.A., and M.G. Yost (1999), Innovative approach for estimating fugitive gaseous fluxes using
computed tomography and remote optical sensing techniques, J. Air Waste Manage. Assoc., 49:8, pp. 966-972.
Hashmonay, R.A., M.G. Yost, and C. Wu (1999), Computed tomography of air pollutants using radial scanning
path-integrated optical remote sensing, Atmos. Environ., 33:2, pp. 267-274.
Hashmonay, R.A., D.F. Natschke, K.Wagoner, D.B. Harris, E.L.Thompson, and M.G. Yost (2001), Field
evaluation of a method for estimating gaseous fluxes from area sources using open-path Fourier transform
infrared, Environ. Sci. Technol., 35:11, pp. 2309-2313.
Hashmonay, R.A., K. Wagoner, D.F. Natschke, D.B. Harris, and E.L. Thompson (2002), Radial computed
tomography of air contaminants using optical remote sensing, presented June 23-27, 2002 at the AWMA 95th
Annual Conference and Exhibition, Baltimore, MD.
Platt, U. (1994), Differential optical absorption spectroscopy (DOAS), In: Air Monitoring by Spectroscopic
Techniques, Chemical Analysis Series, Vol. 127, John Wiley & Sons, Inc. pp. 27-84.
U.S. EPA QA/G4 (2000), Guidance for the Data Quality Objectives Process, EPA-600/R-96/055, Office of
Environmental Information, U.S. EPA, Washington, DC. Also at
http://www.epa.gov/quality/qs-docs/g4-fmal.pdf (accessed April 2005).
U.S. EPA (2004), ECPB Optical Remote Sensing Facility Draft Facility Manual, approved April.
Wu, C., M.G. Yost, R.A. Hashmonay, and D.Y. Park (1999), Experimental evaluation of a radial beam
geometry for mapping air pollutants using optical remote sensing and computed tomography, Atmos. Environ.,
33:28, pp. 4709-4716.
6-1
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Evaluation of Fugitive Emissions at a
6-2
-------
Former Landfill in Colorado Springs, Colorado
Appendix A
OP-FTIR Mirror Coordinates
Table A-1. Standard Distance and Horizontal
Coordinates of Mirrors Used in the HRPM Survey
of Northwest Quadrant.
Table A-3. Standard Distance and Horizontal
Coordinates of Mirrors Used in the HRPM Survey
of Northeast Quadrant.
Mirror
Number
1
2
3
4
5
6
7
8
9
Standard
Distance
(m)
120
87.1
120
106
143
56.7
141
83.3
114
Horizontal Angle
from North
(degrees)
244
253
263
273
276
279
293
305
311
Table A-2. Standard Distance and Horizontal
Coordinates of Mirrors Used in the HRPM Survey
of Southwest Quadrant.
Mirror
Number
1
2
3
4
5
6
7
Standard
Distance
(m)
135
112
135
68.9
155
95.6
131
Horizontal Angle
from North
(degrees)
149
156
180
181
192
208
217
Mirror
Number
1
2
3
4
5
6
7
Standard
Distance
(m)
115
90.5
70.8
140
188
117
173
Horizontal Angle
from North
(degrees)
327
338
5
7
21
30
56
Table A -4. Standard Distance and Horizontal
Coordinates of Mirrors Used in the HRPM Survey
of Southeast Quadrant.
Mirror
Number
1
2
3
4
5
Standard
Distance
(m)
117
74.1
130
108
158
Horizontal Angle
from North
(degrees)
68
92
95
119
127
A-1
-------
Evaluation of Fugitive Emissions at a
Table A-5. Standard Distance, and Horizontal and
Vertical Coordinates of Mirrors Used in the VRPM
Survey of the Northern Border.
Mirror
Number
1
2
3
4
5
Standard
Distance
(m)
116
179
282
180
179
Horizontal
Angle from
North
(degrees)
235
233
234
233
233
Vertical Angle"
(degrees)
0
0
0
2
5
Vertical angle shown is the angle from horizontal (positive values
indicate elevation from the horizontal, negative values indicate
descent from the horizontal).
A-2
-------
Former Landfill in Colorado Springs, Colorado
Appendix B
OP-TDLAS Configuration Path Length Distances
Table B-1. Distance of Path Lengths Used in OP-TDLAS Configurations.
„ . „ Slope Adjacent to
Surface Survey „ ,, „ , 0
A/T- TVT u r>/m/m Southern Boundary Sur-
Mtrror Number on 9/10/03 on ^
^ (m)
1 205 225
2 134 235
3 238 179
4 314 179
5 141 177
6 281 176
7 149 170
8 307 158
B-1
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Evaluation of Fugitive Emissions at a
B-2
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Former Landfill in Colorado Springs, Colorado
Appendix C
Methane Concentrations
Table C-1. Methane Concentrations Found during the HRPM Survey of the Northeast Quadrant.
Cycle
Methane Concentration
(ppm)
Mirror 1
Mirror 2 Mirror 3 Mirror 4 Mirror 5
Mirror 6
Mirror 7
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
.81
.82
.86
.93
.81
.81
.89
.83
.78
.86
.75
.76
.75
.82
.88
.90
.74
.98
.78 1.95 1.80
.78 1.78 1.94
.76 1.79 1.94
.82 1.78 2.09
.72 1.77 1.74
.86 1.90 2.19
.97 2.13 1.97
.77 1.83 1.84
.82 1.94 1.88
.83 1.89 1.79
.75 1.80 1.77
.78 1.87 1.85
.81 1.90 1.85
.91 1.96 1.98
.88 1.88 2.02
.90 1.85 1.93
.74 1.84 1.79
.78 1.80 1.92
.73
.95
.92
.89
.81
.90
.79
.80
.81
.73
.73
.77
.79
.94
.85
.78
.84
.84
.78
.77
.86
.81
.80
.96
.96
.76
.78
.75
.76
.76
.90
.93
.84
.76
.78
.84
.75
.74
.82
.75
.76
.99
.93
.77
.80
.72
.72
.76
.86
.81
.75
.75
.75
.76
C-1
-------
Evaluation of Fugitive Emissions at a
Table C-2. Methane Concentrations Found during the HRPM Survey of the Northwest Quadrant.
Methane Concentration
Cycle (PPm)
Mirror 1 Mirror 2 Mirror 3 Mirror 4 Mirror 5 Mirror 6 Mirror 7 Mirror 8 Mirror 9
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
1.63
1.61
1.64
1.61
1.64
1.61
1.63
1.60
1.63
1.62
1.63
1.64
1.64
1.65
1.66
1.65
1.65
1.64
1.65
1.65
1.63
1.64
1.63
1.66
1.67
1.66
1.67
1.67
1.66
1.67
1.60
1.59
1.59
1.61
1.59
1.60
1.60
1.58
1.61
1.62
1.62
1.63
1.63
1.62
1.63
1.62
1.61
1.62
1.61
1.60
1.59
1.61
1.58
1.61
1.60
1.61
1.64
1.64
1.63
1.66
1.60
1.59
1.60
1.58
1.59
1.60
1.58
1.58
1.58
1.62
1.61
1.62
1.63
1.63
1.62
1.66
1.64
1.66
1.64
1.63
1.65
1.63
1.65
1.65
1.67
1.66
1.68
1.69
1.66
1.67
1.61
1.60
1.60
1.59
1.60
1.61
1.60
1.59
1.63
1.63
1.63
1.64
1.65
1.61
1.62
1.60
1.60
1.62
1.60
1.60
1.60
1.60
1.62
1.63
1.63
1.63
1.64
1.66
1.64
1.63
1.57
1.59
1.59
1.58
1.55
1.58
1.60
1.60
1.60
1.61
1.61
1.61
1.62
1.62
1.61
C-2
-------
Former Landfill in Colorado Springs, Colorado
Table C-3. Methane Concentrations Found during the HRPM Survey of the Southeast Quadrant.
Methane Concentration
Cycle
Mirror 1 Mirror 2 Mirror 3 Mirror 4 Mirror 5
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
1.84
1.75
1.84
1.81
1.91
1.80
1.78
1.88
1.84
1.85
1.84
1.84
1.88
1.88
1.74
1.73
1.82
1.94
1.78
1.98
1.84
1.87
1.76
1.85
1.79
1.83
1.90
1.78
1.89
2.18
1.81
1.85
1.92
1.81
1.92
1.90
1.87
1.97
2.21
1.83
1.93
1.94
1.94
2.00
1.85
1.93
1.86
1.92
1.93
1.92
2.08
1.83
1.97
1.76
2.10
2.11
1.86
2.20
1.84
1.79
1.77
1.97
1.88
1.99
2.03
1.79
1.96
2.04
1.89
1.90
1.83
1.88
2.02
2.13
2.24
1.87
1.76
1.75
1.81
1.75
1.84
1.79
1.86
1.72
1.76
1.76
1.77
1.78
1.78
1.73
1.84
1.84
1.94
1.89
1.86
1.88
1.80
1.79
1.91
1.82
1.76
1.83
1.86
1.73
1.98
1.80
1.77
1.76
1.89
1.85
1.86
1.80
1.75
1.75
1.81
1.94
1.98
1.96
1.95
1.91
1.96
2.01
1.87
1.83
1.77
C-3
-------
Evaluation of Fugitive Emissions at a
Table C-4. Methane Concentrations Found during the HRPM Survey of the Southwest Quadrant.
Methane Concentration
Cycle (Ppm)
Mirror 1 Mirror 2 Mirror 3 Mirror 4 Mirror 5 Mirror 6 Mirror 7
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
1.76
1.75
1.76
1.76
1.76
1.74
1.74
1.78
1.73
1.74
1.73
1.73
1.74
1.76
1.77
1.74
1.73
1.77
1.73
1.74
1.77
1.79
1.75
1.77
1.80
1.75
1.77
1.78
1.75
1.76
1.75
1.75
1.75
1.76
1.75
1.79
1.76
1.75
1.75
1.78
1.74
1.76
1.75
1.76
1.74
1.75
1.74
1.75
1.73
1.74
1.75
1.73
1.74
1.73
1.72
1.73
1.73
1.71
1.71
1.71
1.80
1.79
1.80
1.80
1.79
1.78
1.81
1.81
1.78
1.79
1.80
1.78
1.78
1.78
1.79
1.77
1.78
1.77
1.77
1.77
1.73
1.75
1.75
1.74
1.73
1.75
1.76
1.76
1.73
1.73
1.75
1.73
1.75
1.74
1.74
1.74
1.75
1.72
1.71
1.76
1.74
1.77
1.77
1.75
1.76
1.79
1.79
1.78
1.75
1.77
1.76
1.76
1.79
1.78
1.78
1.77
1.76
1.75
1.75
1.77
1.75
1.75
1.75
1.70
1.75
1.74
1.79
1.74
1.77
1.73
1.73
1.77
1.83
1.80
1.80
1.79
1.78
1.77
1.91
1.74
C-4
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Former Landfill in Colorado Springs, Colorado
Table C-5. Methane Concentrations Found during the VRPM Survey.
Methane Concentration
Cycle
1
2
3
4
5
6
7
8
9
10
11
12
Mirror 1
4.03
4.42
3.55
3.69
4.32
3.75
4.73
3.82
3.96
3.77
3.80
3.60
Mirror 2
3.86
3.61
3.68
3.89
4.15
3.49
3.14
3.25
3.74
3.52
3.64
3.41
Mirror 3
3.28
3.17
3.36
3.28
3.58
2.79
2.84
3.12
3.12
2.77
3.21
3.02
Mirror 4
3.06
2.79
2.81
2.97
3.16
2.39
2.72
3.11
2.76
2.79
3.00
2.85
Mirror 5
2.59
2.36
2.42
2.54
2.71
2.34
2.69
2.60
2.41
2.79
2.46
2.23
C-5
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO.
EPA-600/R-05/041
3. RECIPIENT'S ACCESSION NO.
4. TITLE AND SUBTITLE
Evaluation of Fugitive Emissions at a Former Landfill Site in
Colorado Springs, Colorado Using Ground-Based Optical
Remote Sensing Technology
5. REPORT DATE
April 2005
6. PERFORMING ORGANIZATION CODE
7. AUTHORS
M. Modrak, R.A. Hashmonay, R. Varma, R. Kagann
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
ARCADIS G&M, Inc
4915 Prospectus Dr. Suite F,
Durham, NC 27713
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
EP-C-04-023, WA 0-25
12. SPONSORING AGENCY NAME AND ADDRESS
U. S. EPA, Office of Research and Development
Air Pollution Prevention and Control Division
Research Triangle Park, North Carolina 27711
13. TYPE OF REPORT AND PERIOD COVERED
Final; 09/2003-09/2004
14. SPONSORING AGENCY CODE
EPA/600/13
15. SUPPLEMENTARY NOTES
The EPA Project Officer is Susan A. Thorneloe, Mail Drop E305-02, Phone (919) 541-2709, e-mail
thorneloe.susan@epa.gov
16. ABSTRACT
The report describes an assessment of fugitive landfill gas emissions of methane and VOCs at a former
landfill site in Fort Collins, Colorado. The current owners of the landfill and the State of Colorado requested
assistance from the EPA to search for any fugitive gas emissions from the former landfill site. This
assessment was necessary due to the potential adverse health effects associated with exposure to landfill
gas. An open-path Fourier transform infrared spectrometer, open-path tunable diode laser absorption
spectroscopy, and an ultra-violet differential optical absorption spectrometer were used to make the
assessment survey. The survey detected a methane hot spot in the Northeast quadrant of the site, and the
peak concentration for this hot spot was greater than 0.4 ppm above ambient background levels. Another
methane hot spot was detected in the Southeast quadrant of the site, and the peak concentration for this
hot spot was greater than 0.5 ppm above ambient background. The survey measured an average methane
flux from the site of 4.9 g/s. The location of the peak of the reconstructed methane plume agrees well with
the location of the hot spots, which suggests that emissions from the two hot spots are a major source of
the methane plume.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b. IDENTIFIERS/OPEN ENDED TERMS
c. COSATI Field/Group
Air Pollution
Earth Fills (Landfill)
Emissions
Organic Compounds
Methane
Ammonia
Gasoline
Pollution Control
Stationary Sources
13B
13C
14G
07C
07B
21D
18. DISTRIBUTION STATEMENT
19. SECURITY CLASS (This Report)
Unclassified
21. NO. OF PAGES
48
Release to Public
20. SECURITY CLASS (This Page)
Unclassified
22. PRICE
C-6
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