EPA/450/1-89/002
id States Office of Air Quality EPA-450/1-89-002
Environmental Protection Planning and Standards January 1989
Agency Research Triangle Park NC 27711
Air/Superfund
OEPA AIR / SUPERFUND
NATIONAL TECHNICAL
GUIDANCE STUDY SERIES
Volume II - Estimation
of Baseline Air
Emissions at
Superfund Sites
Interim Final
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VOLUME II
ESTIMATION OF BASELINE AIR EMISSIONS
AT SUPERFUND SITES
INTERIM FITAL
by
Radian Corporation
10395 Old Placerville Road
Sacramento, Califom'a 95827
Prepared for:
Ms. Margaret McDonough
U.S. ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF AIR QUALITY PLANNING AND STANDARDS
RESEARCH TRIANGLE PARK, NORTH CAROLINA 27711
January 1989
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PREFACE
This is one in a series of manuals dealing with air pathway analysis at
hazardous waste sites. This document was developed for the Office of Air
Quality Planning and Standards in cooperation with the Office of Emergency
and Remedial Response (Superfund). It has been reviewed by the National
Technical Guidance Study Technical Advisory Committee and an expanded review
group consisting of State agencies, various groups within the U.S. Environ-
mental Protection Agency, and the private sector. This document is an
interim final manual offering technical guidance for use by a diverse
audience including EPA Air and Superfund Regional and Headquarters staff,
State Air and Superfund program staff, Federal and State remedial and removal
contractors, and potentially responsible parties in analyzing air pathways at
hazardous waste sites. This manual is written to serve the needs of in-
dividuals having different levels of scientific training and experience in
designing, conducting, and reviewing air pathway analyses. Because assump-
tions and judgments are required in many parts of the analysis, the in-
dividuals conducting air pathway analyses need a strong technical background
in air emission measurements, modeling, and monitoring. Remedial Project
Managers, On Scene Coordinators, and the Regional Air program staff,
supported by the technical expertise of their contractors, will use this
guide when establishing data quality objectives and the appropriate
scientific approach to air pathway analysis. This manual provides for flexi-
bility in tailoring the air pathway analysis to the specific conditions of
each site, the relative risk posed by this and other pathways, and the pro-
gram resource constraints.
Air pathway analyses cannot be reduced to simple "cookbook" procedures.
Therefore, the manual is designed to be flexible, allowing use of profes-
sional judgment. The procedures set out in this manual are intended solely
for technical guidance. These procedures are not intended, nor can they be
relied upon, to create rights substantive or procedural, enforceable by any
party in litigation with the United States.
It is envisioned that this manual will be periodically updated to incor-
porate new data and information on air pathway analysis procedures. The
Agency reserves the right to act at variance with these procedures and to
change them as new information and technical tools become available on air
pathway analyses without formal public notice. The Agency will, however,
attempt to make any revised or updated manual available to those who
currently have a copy through the registration form included with the manual.
Copies of this report are available, as supplies permit, through the
Library Services Office (MD-35), U.S. Environmental Protection Agency,
Research Triangle Park, North Carolina 27711 or from the National Technical
Information Services, 5285 Port Royal Road, Springfield, Virginia 22161.
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i
DISCLAIMER
Mention of trade names or commercial products does not constitute
endorsement or recommendation for use by the Air Management Division, U.S.
Environmental Protection Agency.
i
11
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CONTENTS
Page
Disclaimer 11
Tables v1
F1 gures vi 11
Glossary of Frequently Used Terms and Acronyms x
Ac know! edgements xi i i
1.0 Introducti on 1
1.1 The Problem 1
1.2 The Objective 3
1.3 Manual Organization 3
2.0 Air Emissions From Hazardous Waste Sites 5
2.1 General Description 5
2.1.1 Landfills 5
2.1.2 Lagoons 10
2.1.3 Equivalent Units 11
2.2 Routes of Exposure 12
2.2.1 Key Parameters and Critical Factors Affecting
Emissions from Contaminated Soils (Landfills
and Lagoons) 15
2.2.2 Key Parameters Affecting Emissions
from Lagoons 15
2.3 Magnitude of Air Emissions 17
2.4 Emissions of Potential Interest at NPL Sites 17
2.5 Summary of Potential Receptors 21
3.0 Protocol for Baseline Emission Estimates 23
3.1 Protocol Steps for Developing BEEs 23
3.1.1 Define the APA Objective 25
3.1.2 Site Scoping 30
3.1.3 Evaluate Available Site Data 31
3.1.4 Design and Conduct the Site Screening Study 31
3.1.5 Design and Conduct the In-Depth Site Characterization 47
3.2 Use of the BEEs in the Mitigation Process 55
4.0. Air Emission Measurement Techniques 58
4.1 Direct Emission Measurement Technologies 58
4.1.1 Head Space Samplers (Screening Technology) 60
4.1.2 Head Space Analysis of Bottled Samples (Screening
Techno! ogy) 63
4.1.3 Emission Isolation Flux Chamber (In-Depth Technology 66
4.1.4 Portable Wind Tunnels (In-Depth Technology) 70
4.1.5 Soil Vapor (Ground) Probes (In-Depth Technology).... 75
4.1.6 Soil Vapor Monitoring Wells (In-Depth Technology)... 78
4.1.7 Downhole Emissions Flux Chamber (In-Depth
Technol ogy) 81
4.1.8 Vent Sampling (In-Depth Technology) 85
ill
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Contents (Continued)
Page
4.2 Indirect Emission Measurement Technologies 86
4.2.1 Upwind/Downwind (Screening Technology) 87
4.2.2 Mass Balance (Screening Technology) 89
4.2.3 Real-Time Instrument Survey (Screening Technology).. 90
4.2.4 Concentration-Profile (In-Depth Technology) 92
4.2.5 Transect (In-Depth Technology) 95
4.2.6 Exposure Profile (In-Depth Technology) 100
4.3 A1r Monitoring Technologies 101
4.4 Emissions (Predictive) Modeling 102
4.4.1 Emission Models for Closed Landfills without
. Internal Gas Generation... 105
4.4.2' Emission Models for Closed Landfills with Internal
Gas Generation 115
4.4.3 Emission Models for Open Landfills 120
4.4.4 Emission Models for Land Treatment ; 125
4.4.5 Fugitive Dust 128
4.4.6 Additional Models ". 130
4.4.7 Non-Aerated Lagoons 130
4.4.8 Aerated Lagoons 136
5.0 Case Study 137
5.1 Case Study 1: Petroleum Waste Landfill/Lagoon 137
5.1.1 Site History 137
5.1.2 Objectives 138
5.1.3 Scoping 140
5.1.4 Overview of Fieldwork for Site Characterization 142
5.1.5 Undisturbed Emissions Survey 143
5.1.6 Disturbed Emissions Survey ;.. 154
5.1.7 Development of BEEs 155
5.1.8 Summary 158
5.2 Case Study 2: Bruin Lagoon 158
5.2.1 Site History 158
5.2.2 Objecti ves 162
5.2.3 Scoping 162
5.2.4 Overview of Fieldwork for Site Characterization 162
5.2.5 Undisturbed Emissions Survey 164
5.2.6 Disturbed Emissions Survey 164
5.2.7 Development of BEEs 168
5.2.8 Summary 169
5.3 Case Study 3: Lowry Landfill 169
5.3.1 Site History 169
5.3.2 Objectives 172
5.3.3 Scoping 172
5.3.4 Overview of Fieldwork for Site Characterization 172
5.3.5 Undisturbed Emissions Survey 173
5.3.6 Disturbed Emissions Survey 174
5.3.7 Development of BEEs 177
5.3.8 Summary 177
1v
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Contents (Continued)
Page
5.4 Case Study 4: Western Processing Landfill 178
5.4.1 Site History 178
5.4.2 Objectives 179
5.4.3 Overview of Fieldwork for Site Characterization 179
5.4.4 Scoping 182
5.4.5 Undisturbed Emissions Survey 182
5.4.6 Disturbed Emissions Survey 184
5.4.7 Development of BEEs 184
5.4.8 Summary 184
5.5 Case Study 5: Outboard Marine Corp. Lagoon/Landfill 185
5.5.1 Site History 185
5.5.2 Objectives 187
5.5.3 Scoping 188
5.5.4 Overview of Fieldwork for Site Characterization 188
5.5.5 Undisturbed Emissions Survey 189
5.5.6 Disturbed Emissions Survey '. 190
5.5.7 Development of BEEs 190
5.5.8 Summary 190
6.0 References 191
Appendices
A - Annotated Bibliography
B - Chemical and Physical Properties Affecting Baseline
Emission Estimates
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TABLES
Number
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Important Parameters 1n Determining A1r Emissions and Their
Qualitative Effects on Baseline Emission Estimates (BEEs)
Summary of Average Baseline Emissions for Various Emission
Sources
Most Frequently Reported Substances at 546 National Priority
L1 st Sites
Toxic Pollutants Most Commonly Addressed by State and Local
Agend es
Examples of APA Objectives for BEEs
Potential Air Contaminants by Generic Type of Contaminant*
Activities for Developing BEEs: Evaluate Available Site Data...
Factors to Consider In Selecting an Indicator Species for Study.
Examples of Broad-Band, Class, and Indicator Species
Screening Technologies Applicable to Site Screening APA for
Landf 1 11s and Lagoons
Summary Table of Information on the Various Classes of Assessment
Technologies and Screening Assessment Technologies
In-depuh Technologies Applicable to Site Characterization for
Landf 1 lls and Lagoons
Summary Table of Information on the Various Classes of
Assessment Technologies and In-Depth Assessment Technologies
APA Activities Conducted at the Site
Summary of Screening Measurements of Undisturbed Waste
Page
16
18
19
20
27
29
32
37
38
40
41
49
50
141
147
V1
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TABLES (Continued)
Number Page
16 Case Study 1: Summary of Undisturbed Site Emissions Data 148
17 Downwind/Border Monitoring Results 153
18 Summary of Downhole Emissions Data 154
19 APA Activities Conducted at the Case Study 12 Site 159
20 APA Activities Conducted at the Case Study 13 Site 170
21 Summary of A1r Monitoring at Lowry Landfill 175
22 Maximum and Average Concentrations in Soil for Selected
Contaminants 183
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OSHA
OVA
Particulate
Matter
PEL
ppb
ppm
Probe
Quality
Assurance
Quality
Control
RI
RPM
Sampling
SARA
Screening
Technologies
Undisturbed
Condition
VOCs
Occupational Safety and Health Administration, U.S. Department
of Labor.
Organic vapor analyzer.
Airborne solid or liquid matter.
OSHA permissible exposure limit, expressed as ppm or mg/m3 of
substance in air.
Parts per billion.
Parts per million.
A tube used for gas phase concentration sampling or for
measuring pressures at a distance from the actual collection
or measuring apparatus.
A system of activities designed to assure that the quality
control system is performing adequately.
A system of specific efforts designed to test and control the
quality of data obtained.
Remedial Investigation. Field investigations of hazardous
waste sites to determine pathways and nature and extent of
contamination.
Remedial.Project Manager, equivalent to a site manager at
non-NPL sites.
The process of withdrawing or isolating a fractional part of
the whole. In air or gas analysis, it is the separation or a
portion of an ambient atmosphere with or without the
simultaneous isolation of selected components.
Superfund Amendments and Reauthorization Act. Modifications
of CERCLA enacted on October 17, 1986.
Quick and simple methods for estimating baseline emissions.
The condition in which a hazardous waste site is discovered
or may be left if a no-action remedial alternative is
selected.
Volatile organic compounds. An organic compound (containing
carbon) that evaporates (volatilizes) readily at room
temperature.
xii
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FIGURES
Number
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
Conceptual schematic of a landfill
Conceptual schematic of a lagoon
Conceptual schematic showing air contaminant pathways from a
landfill
Conceptual schematic showing air contaminant migration pathways
from a 1 agoon
Flowchart of activities for developing screening and 1n-depth
baseline emission estimates
Checklist of factors affecting air emissions per unit :
Undisturbed site BEE equations
Use of the BEEs data 1n site mitigation
Schematic diagram of a soil core sample sleeve
A cutaway diagram of the emission Isolation flux chamber and
support equl pment
A cutaway diagram of the surface emission Isolation flux chamber
and support equipment for liquid surfaces
Illustration of MRI wind tunnel
Schematic of portable wind tunnel
Schematic diagram of a simple ground probe
Ground probe design with minimal Internal volume
Vapor monitoring well constructions
Schematic diagram of the downhole emissions flux chamber
Real -time instrument survey
Mast sample collection system for C-P sampling :.
Example of transect technique sampling
Flck's correction factor, Fv, plotted against equivalent vapor
pressure, Ce
Page
6
7
13
14
24
35
46
56
65
67
68
71
74
76
77
80
82
91
93
96
121
viii
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FIGURES (Continued)
Number Page
22 Location of suspected disposal area 139
23 Location of waste soil coreholes 151
24 Generalized flow regime of perched zone and bedrock aquifer 161
25 Monitor well and soil boring locations at the Bruin Lagoon Site. 166
26 Western Processing site 180
27 Map of Case Study 5 site 186
1x
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GLOSSARY OF FREQUENTLY USED TERMS AND ACRONYMS
ACGIH
Adsorption
Air
Monitoring
APA
BEEs
Calibration
CERCLA
Co-disposal
Site
Detection
Limit
Direct
Emissions
Measurement
American Conference of Governmental Industrial Hygienists,
6500 Glenway Ave., Building D-5, Cincinnati, OH 45211.
A physical process in which molecules of gas, dissolved
substances, or liquids adhere in an extremely thin layer to the
surfaces of solid bodies with which they are in contact.
A gas phase sampling technique where ambient air is sampled.
It can be used to develop emission rate estimates and is
similar to indirect emission measurement except measurements
usually are taken at greater distances from the waste site.
Air Pathway Analyses. APA are designed to assess the potential
for air emissions from a hazardous waste site.
Baseline Emission Estimates. These are estimates of baseline
emission rates from a hazardous waste site in its undisturbed
conditions.
Establishment of a relationship between the response of a
measurement system obtained by Introducing various calibration
standards into the system. The calibration levels should
bracket the range of levels for which actual measurements are
to be made.
Comprehensive Environmental Response, Compensation and
Liability Act of 1980. Modified by SARA in 1986. The Acts
created a special tax that goes into a trust fund, commonly
known as Superfund, to investigate and clean up abandoned or
uncontrolled hazardous waste sites.
A waste site that has received and mixed municipal and
hazardous wastes.
The minimum quantity of a compound which yields a "measureable
response." Measurable response has many statistical
definitions. Be careful to differentiate "instrumental
detection limit," which refers to the minimum quantity of
material introducible into a measurement system that can be
detected, from "method detection limit," which means the
minimum concentration of a compound in a sample which, when put
through the entire sampling and analysis process, can be
detected.
A measurement made directly on or above the waste to determine
the emission rate of volatile species from a liquid or solid
surface.
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Disturbed
Condition
Emissions
EPA
FS
,Fugitive Dust
»
Hazardous
;In-depth
."Technologies
Indicator
Species
Indirect
Emissions
Measurement
Lagoon
Landfill
mg/m3
NIOSH
NPL
Changes in a hazardous waste site as remediation takes place
that usually involve increasing the emission rate of volatile
species and particulate matter.
The total of substances discharged into the air from a discrete
source.
U.S. Environmental Protection Agency.
Feasibility Study. Analysis and selection of alternative
remedial actions for hazardous waste sites.
Atmospheric dust arising from disturbance of granular matter
exposed to the air; called "fugitive" because it is not
released to the atmosphere in a confined flow stream.
Those wastes that are regulated or "listed" under RCRA (40
CFR Part 261) or wastes that are ignitable, corrosive,
reactive, or toxic.
Very detailed methods for measuring emissions. These
technologies produce detailed, reliable data.
Species found in hazardous waste that can be used to represent
a group of species in determining emissions from a site.
A gas phase sampling technology that measures ambient air
concentrations at short distances down-wind of a hazardous
waste site. Data are collected to satisfy specific needs of
specialized models used to estimate air emissions.
In this manual, lagoon encompasses surface impoundments or
impoundments designed to hold liquid wastes or wastes
containing free liquids.
For purposes of this manual, a landfill is a facility,
usually an excavated pit, into which wastes are placed for
permanent disposal.
Milligrams per cubic meter. This is a measure of mass per
unit volume. The units mg/m3 are commonly used to describe
concen-tra-tions of particulates, dusts, fumes, and mists.
National Institute for Occupation Safety and Health, Centers
for Disease Control, Public Health Service, U.S Department of
Health and Human Services.
National Priorities List. A list of waste sites for which EPA
has assessed the relative threat of site contamination on soil,
air, surface water, ground water, and the population at risk.
Site listing is found under CERCLA (Section 105) and is updated
three times a year.
XI
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ACKNOWLEDGEMENTS
This manual was prepared for the U.S. Environmental Protection Agency by
Radian Corporation, Sacramento, California. Mr. Leigh Hayes (project manager)
and Ms. Susan Fernandes (contract manager) managed the project. Dr. Charles
E. Schmidt served as project director and author of several sections. Other
contributors included Mr. John Clark, Mr. Mark Galloway, Ms. Susan Penner, and
Mr. Bart Eklund. Radian reviewers included Messrs. Bart Eklund and David
Balfour.
Mr. Joe Padgett and his staff at the Office of Air Quality Planning and
Standards, U.S. Environmental Protection Agency, provided overall program
direction. Ms. Margaret McDonough and Mr. Tom D'Avanzo, of the U.S. EPA Air
Management Division, Region I, directed efforts on this particular manual.
Other support was provided by the program's Technical Advisory Committee,
the members of which include:
Mr. Joe Padgett, U.S. EPA OAQPS
Mr. Jim Durham, U.S. EPA OAQPS
Mr. Stan Sleva, U.S. EPA OAQPS
Mr. Joe Tikvart, U.S. EPA OAQPS
Mr. Ed Lillis, U.S. EPA OAQPS
Mr. Jim Southerland, U.S. EPA OAQPS
Mr. David Dunbar, PEI Associates, Inc.
Mr. Jim Vickery, U.S. EPA HSCD
Mr. Abe Ferdas, U.S. EPA Region III
Mr. Joe Lafornara, Chief, Emergency Response Team, NOA
Mr. John Summerhays, U.S. EPA Region V
Ms. Margaret McDonough, U.S. EPA Region I
Mr. Mark Garrison, U.S. EPA Region III
Mr. Al Cimorelli, U.S. EPA Region III
Mr. Ron Stoner, NUS Corporation
Mr. Tom Pritchett, Emergency Response Team
Mr. Bart Eklund, Radian Corporation
Dr. Chuck Schmidt, Radian Corporation
This program also received support from the Regional Air Superfund
Program and its participants.
xiii
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SECTION 1
INTRODUCTION
The United States Environmental Protection Agency (EPA) Is responsible
for the assessment and cleanup of the National Priority List (NPL) sites under
CERCLA and SARA. EPA's Remedial Program Managers (RPMs) are required to
assess the potential for air emissions and air quality impacts caused by NPL
sites prior to and during cleanup. To date, no standard approach for
assessing the air pathway at NPL or other hazardous waste sites has been
available. As a result, performing air pathway analyses (APA) -has been less
straightforward than evaluating other pathways such as the impacts on ground
water or surface water quality. This manual assists RPMs in determining if an
uncontrolled site has the potential for significant air emissions and, if so,
how to characterize the baseline air emissions potential from the site.
This volume is one in a series of manuals prepared for EPA to assist
its RPMs in the assessment of the air contaminant pathway and developing input
data for risk assessment. Volume I (1) of the series provides overview and
directional information for the RPM in the overall Superfund process. This
manual (Volume II) provides guidance on developing baseline emission estimates
from hazardous waste sites. Baseline emission estimates (BEEs) are defined as
emission rates estimated for a site in its undisturbed state. Applications of
BEEs are found in additional volumes: Volume III (2) provides guidance on
estimating emissions from cleanup activities using these baseline emission
estimates and other means; and Volume IV (3) provides guidance on ambient air
monitoring and on dispersion modeling using baseline emissions or other source
term data to predict ambient concentrations at locations of concern.
1.1 THE PROBLEM
CERCLA and SARA mandate the characterization of all contaminant migration
pathways from the waste or hazardous material to the environment and
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evaluation of the resulting environmental Impacts. However, air pathway
analyses are often overlooked because many sites emit little or no perceptible
air emissions In their baseline or undisturbed state. Exposure to the
elements over time often causes surface materials to develop a type of surface
crust which tends to Impede volatile emissions. This type of surface can also
reduce emissions of part1culate matter. However, all sites have the potential
to generate air emissions at some level during cleanup, and It Is essential to
anticipate these emissions. Emissions of potential concern Include volatile
and semi-volatile organlcs, acid gases, part1culate matter, and toxics
associated with windblown particulate matter such as metals, PCBs or dioxins.
A remedial Investigation Is typically necessary to either provide data on
air emissions from the site directly, or to provide chemical and physical data
that can be used as Inputs to model the emissions. Remedial investigations
(RIs) often Include ambient air monitoring to assess baseline air quality
Impacts from the site, but measurements of emission rates or soil-gas
concentrations are less widely employed. An Introduction to these techniques
is a major emphasis of this manual. Emission rate or soil-gas data can be
useful for: 1) identifying "hot spots" e.g. areas of higher than average waste
content or pockets of subsurface gases, 2) serving as model inputs (source
terms) to estimate ambient air concentrations under meteorological conditions
other than those encountered during the RI, and 3) estimating emissions during
remediation. For this last use, the air emissions investigation during the RI
stage would Include emission measurements of both the undisturbed wastes and
the exposed or disturbed wastes.
While not strictly part of baseline emission estimates, measurements of
emissions from exposed or disturbed wastes can generally be performed during
the RI using the same techniques presented in this manual for performing
baseline emission measurements. These data along with the BEEs can be used in
the procedures outlined 1n Volume III of this series to help to evaluate
remediation options, design an engineering approach to the site mitigation,
and determine whether air emission control technologies or an air monitoring
program may be necessary as part of the remedial alternatives.
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1.2 THE OBJECTIVE
The overall objective of this manual Is to assist RPMs or site managers
1n assessing the Impacts on air quality from the site In Its undisturbed
condition. Specifically the manual 1s Intended to:
Present a protocol for selecting the appropriate level of effort to
characterize baseline air emissions.
Assist site managers in designing an approach for estimating
baseline emissions.
Describe useful technologies for developing site-specific baseline
emission estimates (BEEs).
Help site managers select the appropriate technologies for
generating site-specific BEEs.
However, this manual has limitations:
The manual is a decision making tool but it is not intended to
relieve the site managers of their decision making responsibility.
The protocol is not a "cookbook" for designing air pathway
investigations or for determining BEEs.
The determination of BEEs for a site will not by itself, yield an
assessment of actual or potential air impacts, but it is a useful
part of that evaluation process.
1.3 MANUAL ORGANIZATION
This manual (Volume II) provides general information on the potential for
air contaminant emissions from hazardous waste sites in Section 2. Section 3
offers a protocol for determining if BEEs are required and how to develop
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site-specific BEEs. Information on technologies used to obtain BEEs Is
provided In Section 4. Section 5 describes case studies In which BEEs were
needed and/or determined for hazardous waste sites.
References are given 1n Section 6. An annotated bibliography of the
Information reviewed for this project 1s Included as Appendix A. This
literature was Identified during a computer-assisted search of 15 databases
and a telephone survey of regional EPA personnel, employees of EPA research
offices, EPA contractors, university researchers, and referrals from those
contacted. Appendix B Identifies chemical and physical properties of waste
material that may affect 1s emissions potential.
For this manual, all types of uncontrolled solid waste sites, land
disposal sites 1n particular, will be referred to as "landfills" and all types
of uncontrolled liquid waste sites will be referred to as "lagoons." The
technologies described for application to landfills and lagoons may generally
be applied to solid and liquid hazardous waste, respectively.
1
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SECTION 2
AIR EMISSIONS FROM HAZARDOUS WASTE SITES
This section presents information on landfills and lagoons, the two
general types of sites used in this manual to demonstrate methods for
"estimating the potential for air emissions. This section addresses potential
emission sources and potential air quality impacts. Discussion of potential
air quality impacts covers the general types of air quality impacts by waste
site category, and the basic transport mechanisms involved with the movement
of contamination from lagoons and landfills. Where not otherwise specified,
the general term hazardous waste site is used to refer to both landfills and
lagoons that contain hazardous wastes and/or substances. Figures 1 and 2
depict these two types of sites in generalized schematic drawings.
The site, and contaminant characteristics discussed below are general
background information for working with the protocol presented in Section 3.
The information provided will assist the site manager in developing conceptual
models of landfills and lagoons. Based on this conceptual understanding, the
site manager can then develop strategies for assessing the potential impacts
and for estimating potential air emissions from these sites. The references
cited in this section and those listed in the annotated bibliography contain
further background material.
2.1 GENERAL DESCRIPTION
2.1.1 Landfills
Landfills are facilities into which wastes are placed for permanent
disposal, and usually are simply an excavated pit. Landfills may vary in size
from a few tenths of an acre to several hundred acres and other landfill
characteristics can also vary greatly from one site to the next. Most
variations are attributable to the types of stored wastes, the operating
practices and the age of the facility, and hence, its design.
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Commercial landfills can be categorized by design criteria such as liners
and gas-venting systems. Older landfills are usually unlined. Newer landfill
designs may specify liner systems to retard transport of leachate and wastes
Into soils and ground water. Some landfills have built-in gas venting systems
to prevent build up of landfill gases.
Landfills can be further differentiated by the types of waste they store.
Commercial landfills are commonly classified as municipal or hazardous,
depending on the types of waste accepted. Municipal landfills accept solid,
semi-solid, and liquid nonhazardous wastes, including garbage, glass,
plastics, paper, plant matter, ashes, some Industrial wastes, and demolition
and construction wastes.
Hazardous waste landfills accept hazardous sludge, liquids, semi-solids,
residues, concentrates, or leachate or ash originating from a waste. Much of
the hazardous waste originates from manufacturing, petrochemical, and chemical
industries. Federal, state, and local regulations establishing minimum design
standards and restricting types of acceptable landfill wastes have evolved
over the last 25 years. In the past, mixtures of liquid and solid waste were
common practice. Today, landfills can no longer accept liquid wastes or
solids that contain free liquids unless they've been treated with fixatives
and stabilizers to eliminate the free liquids prior to disposal.
Co-disposal landfills are sites that have received and mixed municipal
and hazardous wastes. Any available disposal records may relate types of
wastes and location/mixing within the landfill.
Most landfills that are selected as Superfund sites have undergone some
form of closure. In some cases, currently operating facilities may have
abandoned hazardous landfills at the same site. The appearance of a closed
landfill will depend on when it was closed. Closure may mean that the site is
covered with vegetation or that no waste is exposed. Telltale signals of
covered waste are seeping leachate and odors. In the past, landfills were
often sited in"unpopulated areas ^lose to the industry or industries
8
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generating the wastes, but population growth and development may result in
people living or working in close proximity to the site.
Superfund sites may differ 1n significant ways from the types of
commercial landfills discussed above. In some cases, the site history will be
one of relatively Indiscriminate disposal of hazardous substances. The sites
may contain burled drums or pockets of dumped/spilled wastes that are not
, uniformly distributed across the disposal area. Information on waste types,
, disposal practices, date of disposal, etc. may be limited or non-existent.
However, the protocol and measurement techniques presented in this manual are
sufficiently generalized that they can be applied to such uncontrolled sites.
Conversely, the emission models presented here may be of only limited use for
sites where the chemical and physical parameters that serve as"model inputs
are poorly defined.
Potential Site Conditions--
3 The site conditions encountered when investigating landfill sites will
fe vary from site to site because of the siting, landfill design, landfill use,
, and difference in landfill operations among each of the sites. Figure 1
presents a conceptual schematic of a landfill site. The condition of the site
cover material will vary greatly. It will depend, to a large extent, on the
landfill's operational history. In the best situation, the landfill cover
will extend over the entire land disposal area; the cover will have been
constructed to minimize rainfall percolation into the waste body and regulated
to minimize erosion of the cover. The degree to which the air, the
surrounding native soils, and the ground water are protected from
contamination from the wastes stored in the landfill will depend both on the
landfill design and on the construction and operation of the waste storage
facility. If the wastes have been disposed of into an unlined storage area,
the likelihood of contamination of surrounding soils and eventual
contamination of the ground-water beneath the landfill increases. If the
landfill has been constructed at or below the ground-water table, the
transport of pollutants Into the ground water further increases. Waste
material 1n the landfill may be stratified by age of disposal and/or settling
of the more dense waste."
-------
Emission of air pollutants from landfills 1s dependent on the chemical
and physical properties of the stored wastes and on the landfill design
components which may have been Implemented to reduce air emissions. Municipal
landfills are sources of significant amounts of methane and carbon dioxide,
and variable amounts of other non-methane hydrocarbons. Hazardous waste
landfills often are sources of non-methane hydrocarbons, including volatile
organic compounds (VOCs), semi-volatiles, and pesticides. Co-disposal sites
combine the emission potentials of both municipal and hazardous waste sites.
The methane gases generated often can Increase the migration potential of the
high concentrations of non-methane hydrocarbons by acting as a carrier medium
during bulk flow transport of these contaminants. For this reason,
co-disposal sites may generate very high emission rates compared to other
types of landfills.
2.1.2 Laaoons
For purposes of this discussion, the term "lagoon" refers to the class of
facility also known as surface impoundment or impoundment. This type of
facility generally includes a natural topographic depression, a man-made
excavation, or a diked area formed primarily of earthen materials. Lagoons
are designed to hold liquid wastes or wastes containing free liquids. Lagoons
include holding, storage, settling, and aeration ponds.
These waste sites may range in surface area from a few tenths of an acre
to hundreds of acres. Man-made lagoons typically range in depth anywhere from
> 2 to 30 or more feet below land surface.
In some cases, for certain wastes, lagoons may be lined to minimize any
fluid seepage. Clay, asphalt, soil sealant, and synthetic membranes are
typical lining materials.
To prevent migration of pollutants into the native soils and ground water
r beneath the lagoon, lagoons are usually built above the naturally occurring
water table and take advantage of any impermeable surface or subsurface soils.
10
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In areas with high ground-water tables, lagoons may be constructed on the land
surface to minimize ground-water contact. Of course, use of liners and
building above the water table will not prevent the release of contaminated
air emissions from the surface of the lagoon, but these practices limit the
possible routes of air emissions (see Section 2.2). Equally as Important are
operating practices and waste types 1n the lagoon. The Importance of these
factors tends to parallel the landfill discussion above, as does the
Importance of lagoon siting practices.
Potential Site Conditions--
Actual site conditions that will be encountered when investigating
hazardous waste site lagoon sites will vary because of siting, lagoon design,
lagoon usage, and differences in lagoon operations. Figure 2 presents a
conceptual schematic of a lagoon site. The condition of the lagoon will
depend, 1n large part, on the wastes stored there and the lagoon's operational
history. Mixed wastes within the lagoon will often have separated into
stratified layers. The lighter materials are near the surface, the denser
sliquids, sludges, and sediments have settled to the lagoon bottom.
Contaminated soils around and beneath the lagoon are likely, as well as
: contamination of the underlying ground water.
2.1.3 Equivalent Units
NPL sites containing mixed wastes or having other types of inherent
variability may require separate remedial options to be considered for each
equivalent area. During the remedial investigation, the site should be --
theoretically divided into units of equivalent waste for estimating baseline
emissions and evaluating potential emissions during remediation. For example,
a site containing an abandoned landfill, sludge pits, and buried drums would
have at least three distinct units and maybe more. If the type,
concentration, or distribution of a given form of contamination varies, then
further subdivision of the units should be considered. Similarly, if the soil
media or proximity of receptors varies significantly across the site, then
further subdivision of the units may be warranted.
11
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2.2 ROUTES OF EXPOSURE
Waste site characterizations performed during a remedial Investigation
are Intended to determine potential or existing contaminant migration by the
direct contact, surface water, ground water, and air pathways. Each pathway
represents a potential route of exposure to the public and the general
environment. Figures 3 and 4 show the potential routes for contaminant
migration from landfills and lagoons, respectively. The focus of this manual
1s the air pathway, and several routes exist for contaminant emissions within
this one pathway.
Emissions from surface wastes may occur as gaseous volatile organics and
Inorganics as gases, aerosols, and contaminated particulate matter. Where gas
migration controls, (e.g., gas venting systems) have been installed, volatile
emissions from the controls are likely to be higher than emissions from the
site surface. The lateral migration of solid and liquid wastes into the
surrounding soils and beneath the containment area can create large areas of
contaminated subsurface soils. The contaminated soils also represent a source
of potential air emissions via the transfer of contaminants into the air-
filled spaces in the soil matrix. The contaminated soil gas can then transfer
contaminants into the atmosphere at the surface soil/atmosphere interface.
The generation of leachate from landfills and lagoons can accelerate the
pollutant migration into the ground water below and provide an additional
source of air emissions resulting from the volatilization of dissolved
contaminants in the ground water. The contaminated ground-water also can
transfer contaminants Into the soil gas and hence the atmosphere.
12
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2.2.1 Kev Parameters and Critical Factors Affecting Emissions from Landfills
The generation of emissions from landfills depends on several key
chemical and physical properties of the waste materials stored at these sites.
Table 1 presents these key factors along with the qualitative effects these
factors may have on baseline emissions. These data can be used to help
estimate the potential air emissions from the site, given critical factors
imposed by the site. A discussion of each parameter is outside the scope of
this document, but in general, for volatile compounds the rate limiting step
is the movement of vapors through the soil. Volatilization into the soil pore
spaces and transfer from the soil -gas into the atmosphere once the soil/air
interface has been reached, are usually quite rapid. Additional information
about the key physical and chemical properties of the waste material are
presented in Appendix 8. Users should consult the references cited below and
those listed in the annotated bibliography (Appendix A) for additional
- background material. General reading materials that may prove helpful
include: Guidance Document for Cleanup of Surface Impoundment Sites. (4)
... Model Prediction of Volatile Emissions. (5) Air Pollution Assessment of "toxic
'Emissions from Hazardous Waste Lagoons and Landfills. (6) Air Quality
«
Assessment for Land Disposal of Industrial Wastes. (7) Estimating Air
Emissions 'from Disposal Sites. (8V and Air Pollution Problems of Uncontrolled
Hazardous *jaste Sites.
2.2.2 Kev Parameters Affecting Emissions from Lagoons
Figure 4 presents a generalized schematic of the volatilization process
from lagoons. In general, the process consists of two steps: vaporization
from the surface liquid layer Into the boundary air layer and then mass
transfer from the boundary layer to the bulk atmosphere. The rate of
vaporization is dependent on factors such as the compound's concentration,
Henry's Law constant, water solubility and the system temperature. Mass
transfer into the bulk atmosphere is dependent on compound properties such as
molecular weight and diffusion coefficient, and site-related factors such as
15
-------
TABLE-1. IMPORTANT PARAMETERS IN DETERMINING AIR EMISSIONS
AND THEIR QUALITATIVE EFFECTS ON BASELINE EMISSION
ESTIMATES (BEEs)
Parameter
Qualitative Effect on BEEsa
Volatile;
Participate Matter
Site Conditions
Size of Landfill or Lagoon
Amount of Exposed Waste
Depth of Cover on Landfills
Presence of Oil Layer
Compaction of Cover on Landfills
-Aeration of Lagoons
Ground Cover
Weather Conditions
Wind Speed
Temperature
Relative Humidity
Barometric Pressure
Precipitation
Solar Radiation
Soil/Waste Characteristics
Physical Properties of Waste
Adsorption/Absorption
Properties of Soil
Soil Moisture Content
Volatile Fraction of Waste
Semi-Volat11e/Non-Volati1e
Fraction of Waste
Organic Content of Soil
and Microbial Activity
Effects overall Effects overall
magnitude of emissions magnitude of
but not rate per area, emissions, but not
rate per area.
High
Medium
High
Medium
High
Medium
Medium
Medium
Low
Medium
High
Low
High
Medium
High
High
Low
High
High
High
High
Low
High
High
High
Low
Low
Low
High
Low
High
Low
High
Low
High
Low
8 High, medium, and low in this table refer to the qualitative effect that the
listed parameter typically has on baseline emissions.
16
-------
temperature, pressure, and wind speed. Berms, wind breaks, and lagoon
geometry affect the wind speed at the liquid surface and can thereby control
the rate of mass transfer. In general, low molecular weight compounds are
more volatile than high molecular weight compounds.
2.3 MAGNITUDE OF AIR EMISSIONS
The magnitude of baseline air emissions from landfills and lagoons is
dependent on waste-specific chemical and physical factors and site-specific
environmental factors. Limited data are available on measured air emission
fluxes (rate per area) from previously studied waste sites (Table 2). These
data can be used to give the site manager some idea of typical baseline
emission estimation (BEEs) and a limited comparison of BEEs for* different
types of waste sites. Emission flux data for disturbed or exposed wastes are
included to demonstrate the potential for increased emissions for volatiles
during waste remediation.
-2.4 EMISSIONS OF POTENTIAL INTEREST AT NPL SITES
The types of emissions at a hazardous waste site are dependent on the
types of waste present, and these in turn are dependent on the types of
industries and manufacturers that produced the waste. A listing of the
typical wastes generated by 30 various industries and manufacturers can be
found in the Handbook of Industrial Waste in California (II). The 25 most
frequently detected compounds at 546 hazardous waste sites are summarized in
Table 3 according to the type of media, i.e., groundwater, surface water, or
air. The table shows the number of sites where each contaminant was detected
and the contaminant's relative rank for each type of media. Another useful
listing for selecting contaminants with the potential for emissions of
concern, is the list of toxic compounds most commonly addressed by state and
local regulatory agencies given as Table 4.
17
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TABLE 2. SUMMARY OF AVERAGE BASELINE EMISSIONS FOR VARIOUS EMISSION SOURCES
i
Waste Type
Source Type
Baseline
Emission Estimate
For TNMHC*
(ug/m -min)
Industrial Waste TSDFC Facilities
Active Landfills
Site E
Site F
Site G
Inactive Landfills
Site H (covered)
Site I (covered)
Land Treatments
Disturbed
or Exposed
Waste Emissions
For TNMHC
(ug/mz-min)
NPL/Hazardous
Waste Sites
Landfills
Site A
Site B
, Site C
Laooons
Site D
360
740
29
43
190,000
26,000
170,000
640,000
44-150
47
9
Site J
Lagoons
Site K
Site L
Site M
Site N
120
570
9-31b
630
610-9600
_ __
a TNMHC - Total Non-Methane Hydrocarbons.
Different assessment techniques were used.
c Transfer, storage, and disposal facilities (RCRA) - Reference 10.
18
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TABLE 3. MOST FREQUENTLY REPORTED SUBSTANCES AT 546 NATIONAL PRIORITY
AIST SITES
Substance Identified at
Hazardous Waste
Disposal Sites
Sites"
Ground Water
Sites (Rank)b
Surface Water
Sites (Rank)b
Air
Sites (Rank)bc
Most Frequently Occurring
1. Trlchloroethylene
2. Lead
3. Toluene
4. Benzene
5. Polychlorlnated Blphenlys (PCBs)
6. Chloroform
7. Tetrachloroethylene
8. Phenol
9. Arsenic
10. Cadmium
11. Chromium
12. 1.1.1-THchloroethane
13. Zinc and Compounds
14. Ethylebenzene
15. Xylene
16. Hethylene Chloride
17. Trans-l,2-D1chloroethylene
18. Mercury
19. Copper and Compounds
20. Cyanides (Soluble Salts)
21. Vinyl Chloride
22. l,2-D1chloroethane
23. Chlorobenzene
24. l.l-D1chloroethane
25. Carbon Tetrachlorlde
179
162
153
143 ,
121
111
90
84
84
82
80
79
74
73
71
63
59
54
47
46
44
44
42
42
40
127 (1)
77 (4)
81 (3)
84 (2)
29 (21)
70 (6)
57 (7)
43 (9)
45 (8)
28 (16)
34 (14)
58 (6)
28 (17)
36 (12)
32 (15)
36 (13)
42 (10)
27 (20)
17 (24)
16 (25)
28 (18)
25 (21)
23 (23)
28 (19)
25 (22)
49 (3)
84 (1)
40 (4)
36 (5)
54 (2)
24 (11)
17 (14)
28 (8)
35 (6)
28 (9)
33 (7)
20 (12)
27 (10)
14 (20)
8 (25)
17 (15)
17 (16)
20 (13)
16 (18)
16 (19)
10 (23)
17 (17)
9 (23)
8 (24)
12 (21)
8
7
16
18
6
1
3
3
2
31
1
3
2
7
9
2
1
4
6
2
4
2
0
0
2
"Number of sites at which substance 1s present. Substances may be present In
one, two, or all three environmental media at all sites at which it is known
to be rpesent. Therefore, the number of sites at which each substance is
detected in environmental media may not equal the number in this column.
bNot all ranks will be represented in all media because not all chemicals
found in media are among those found most frequently at site.
cVolatile organics not otherwise specified were reported as being detected
most often (rank 1) in the air medium.
Source: Air Quality Engineering Manual for Hazardous Waste Site Mitigation
Activities.17
19
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TABLE 4. TOXIC POLLUTANTS MOST COMMONLY ADDRESSED BY STATE AND LOCAL AGENCIES
Acetaldehyde
Acroleln
Acrylonltrile
Ally! Chloride
Arsenic
Asbestos
Benzene
Benzidine
Benzo(a)pyrene
Benzyl Chloride
Beryllium
Bis(chloromethyl)ether
1,3-Butadiene
Cadmium
Carbon Tetrachloride
Chlordane
Chlorobenzene
Chloroform
Chloroprene
Chromium
Cresol
1,4-Di chlorobenzene
3,3-Dichlorobenzidine
Dimethyl Sulfate
1,3-Dioxane
Dioxins
Epichlorohydrin
Ethylene Dibromide
Ethylene Dichloride
Ethylene Oxide
Ethylenimine (azridine)
Formaldehyde
Heptachlor
Hexachlorocylopentad i ene
Hydrazine
Hydrogen Sulfide
Lead
Lindane
Maleic Anhydride
. Manganese
Mercury
Methyl Bromide
Methyl Chloride
Methyl Chloroform
Methylene Chloride
beta-Naphthylamine
Nickel
Nitrobenzene
n-Ni trosodimethylami ne
Nitrosomorpholine
Parathion
Perchloroethylene
Phenol and Chlorinated Phenols
Phosgene
Polychorinated Biphenyls (PCBs) *<
Polycyclic Aromatic Hydrocarbons (PAH)
Propylene Oxide
Radionuclides
Styrene
1,1,2,2-Tetrachlorethane
Tetrahydrofuran
1,1,2-Trichloroethane (vinyl trichloride)
Toluene
Trichoroethylene
Vinyl Chloride
Vinylidene Chloride
Xylene
Source: Reference 12.
20
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2.5 SUMMARY OF POTENTIAL RECEPTORS
Receptors can be divided Into three broad categories:
On-site workers;
Off-site populace; and
Non-human receptors.
The on-site workers are in the closest proximity to the hazardous waste
site and are potentially subject to the most acute exposure to hazardous
substances. The use of personal protective equipment, real-time field
Instruments, personnel monitoring, site controls, and designated work zones
are designed to ensure that field personnel are properly protected against the
hazards present at the work site.
The off-site (and any on-site) population in close proximity to the
hazardous waste site Is another receptor of primary concern. These people are
often acutely aware of the hazardous waste site and the potential for *
contaminant exposure. Section 3 provides an approach for estimating emissions
which can subsequently be used to predict the airborne contaminant
concentration for downwind receptors to assist in the establishment of
appropriate action levels. Use of this r Jtocol, coupled with an effective
monitoring and modeling program, will provide useful information for the
site's community relations program.
Non-human receptors also may be a concern at some hazardous waste sites.
Disturbance of the site may lead to exposure through inhalation of
contaminated air or exposure through ingestion of or direct contact with
contaminants deposited on plant and inert surface. The possibility of
Inhalation exposure may affect feral or domesticated animals downwind of the
site. This also impacts humans in that animal exposure to pollutants can lead
to contamination accumulation in the food chain.
21
-------
Certain gaseous pollutants (e.g., ozone, oxides of sulfur and nitrogen),
If present In high concentrations, also can affect plant and animal growth.
Deposition of airborne contaminants may cause stressed vegetation, release
pesticides and herbicides, or Impact the value/usability of agricultural
crops. Also, deposition of metals or other pollutants In surface waters may
Impact marine life. Copper and some other metals can cause fish kills at very
low concentrations.
22
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SECTION 3
PROTOCOL FOR BASELINE EMISSION ESTIMATES
This section presents a protocol for developing baseline emission
estimates (BEEs). This protocol 1s a component of an air pathway analyses
(APA) program to assess potential air quality Impacts from hazardous waste
site landfills and lagoons. While not all sites will require BEEs, the first
three steps in the protocol should be Implemented to see if BEEs are necessary
for a given site. The protocol Is a recommended guideline; the level of
effort that Is required or the need to develop BEEs for Individual sites must
be determined on a case-by-case basis.
3.1 PROTOCOL STEPS FOR DEVELOPING BEEs
Figure 5 diagrams a protocol for developing BEEs. The protocol was
developed to help the site manager to determine baseline emission rates and
absolute emissions. These values can be used as Inputs to dispersion models
to assess the air Impacts for receptor locations of Interest. The activities
Identified in this flow chart are consistent with tfr steps of the CERCLA
remedial investigation process that involve the assessment of the air
contaminant migration pathway. Although the protocol was developed for NPL
sites, it also applies to assessing air emissions from other hazardous waste
sites. The flow chart is applicable to all sites, regardless of the type of
site (landfill, lagoon, waste pile, etc.), type of waste, or the potential for
the site to generate air emissions. Each step of the protocol is described
below.
23
-------
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Define the APA Objectives
Design and Conduct the
Site Scoping
Evaluate the Available
Site Data
Potential Exists for
Air Pathway Contamination
I
Design and Conduct a
Screening APA to Determine If
In-Depth Baseline Emission
Estimate Data Are Necessary
Design and Conduct Detailed
APA To Determine In-Depth
Baseline Emission Estimate
No
Potential
Document
N<5 Potential for
Air Pathway
Contamination
In-Depth Baseline
Emission Estimate
Data Are Not
Necessary
In-Depth Baseline Emission I
Estimate Data Are Necessary I
Document
Screening
Baseline Emission
Estimate Data
Report In-Depth Baseline
Emission Estimate
Sufficient
APA Data
Site
Mitigation
Figure 5. Flowchart of activities for developing screening and in-depth
baseline emission estimates.
24
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3.1.1 Define the APA Objective
CERCLA and SARA legislation highlight the basic objectives for all
remedial investigations. Simply stated,.these objectives are to provide data
that are "necessary and sufficient" to characterize the "nature and extent" of
contamination on site. In addition, they mandate that "all potential
migration pathways for contaminations" require characterization. As the first
step of the protocol to assess baseline emissions, site-specific objectives
should be developed; this will generally occur simultaneously with the
performance of Steps 2 and 3 (data collection :and review) of the protocol.
The site manager should consider the following issues when formulating
site-specific objectives:
What information is already available? As described in Section
3.1.2, available information should first be reviewed before
developing final site-specific objectives. This preliminary review
of information will provide necessary background information and aid
1n Identifying data gaps. ' ' *
What pathways must be considered? Except in rare cases, all
pathways, namely air, soil, and water, must be considered.
What is technically possible? Site and situational factors that may
adversely affect the air pathway investigation should be identified
to avoid establishing unrealistic objectives. These factors can
range from complexity in site geology/hydrogeology and complex '
terrain to the feasibility of detecting the contaminants of
interest. :
What time deadlines exist? Schedule constraints can affect the
nature of the investigation and must be balanced with technical
concerns.
What data quality ob.iectives are required? Data must be of a known
accuracy and precision for use in evaluating the air pathway.
25
-------
What program is most cost effective? The type, level, and extent of
contamination per migration pathway will primarily determine how the
available resources are apportioned. It Is also necessary to
collect, Integrate, and consider a variety of types of data,
Including technical Information, Institutional Issues, political
Issues, public protection, community relations Issues, and community
concerns.
What contaminants must be considered? The Investigation will
typically Involve Identifying and characterizing the extent of the
contamination. Concentrations of Individual or summed indicator
compounds are often selected to represent the extent of total
contamination. Site-specific objectives should neither identify
specific Indicator compounds nor require characterization of all
compounds.
Table 5 provides examples of objectives related to baseline emissions
estimates. The first step in developing site-specific APA objectives is to
collect and review readily available site historical records. The potential
,for air emissions can be inferred from the review of preliminary site
information. While baseline emiss'nns may be low, during remediation sites
have the potential for air emissions of particulate matter (semi-volatile
organics, metals, and other Inorganic contaminants) and enhanced volatile
organic emissions.
Among the types of information that can be reviewed and used to develop
site-specific APA objectives are: waste characteristics; distribution of the
waste; orientation of the general public to the emission source concerns;
technical feasibility; and program resources. The first three items are
discussed below.
26
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TABLE 5. EXAMPLES OF APA OBJECTIVES FOR BEEs
Characterize the air emissions potential for volatile species and
participate matter from the undisturbed site.
Characterize the air emissions potential for volatile species and
particulate matter from the disturbed site.
Identify contaminants of concern.
Provide baseline emission estimates that can be used to assess the
health risk and the need to mitigate.
Provide baseline emission estimates that can be used to assess the
need for on-site or fenceline ambient monitoring.
27
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Waste^ Characteristics. Knowledge of the Industrial process or the
waste source Involved can suggest the types of chemicals or agents
that may be 1n the waste. For example, volatile emissions are
likely from waste sites with organic solvents or petroleum waste.
Wastes In liquid form tend to have higher baseline emissions than
wastes In solid form. In addition, Identifying common decomposition
products of the chemicals Identified 1n the waste may be useful. It
Is helpful to categorize potential air contaminants by their generic
volatility: volatlles, semi-volatlies, and non-volatiles. Examples
of the-types of compounds in each category are listed in Table 6.
The categories group together compounds with similar physical
behavior in the atmosphere and thus are useful for predicting
emissions potential.
Distribution of the Waste. The relative position of the waste can
Influence the potential for air emissions and, thus, the APA
objectives. The amount and nature of overburden strongly influences
the baseline emissions at a site. Semi-volatiles and non-volatiles
present near the surface can be emitted as windblown particulate
matter. Waste piles may have relatively high emissions of both
volatile organics and particulate matter due to their geometry and
surface area to volume ratio.
Location of the Affected Population and Community Concerns. The
population potentially at risk from exposure to toxic air emissions
from the site must be identified and the exposure characterized.
The close proximity of residential areas may require the addition of
measurement and monitoring activities for health and safety purposes
that are beyond what is necessary to develop BEEs for the site.
Thus, the site-specific objectives may Include a component related
to determining the potential impact on the nearest population (e.g.,
air monitoring at the site boundary).
28
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TABLE 6. '"POTENTIAL AIR CONTAMINANTS BY GENERIC TYPE OF CONTAMINANT
VolatHes (>1 mm mercury vapor pressure)
All monochlorlnated solvents; also trlchloroethylene,
tr1chloroethane, tetrachloroethane
Most simple aromatic solvents; benzene, xylene, toluene,
ethyl benzene
Some normal alkane; up to decane
Inorganic gases; hydrogen sulfide, chlorine, .sulfur dioxides
Semivolatlles fl-10'7 mm mercury vapor pressure)
*
Most polychlorinated biphenyls; dichlorobenzenes, aroclors, dieldrin
Most pesticides; aniline, toxaphene, nitroanillne, parathi on,
phthalates
Most complex alkanes; dodecane, octadecane, hexacosane
Most polynuclear aromatic's; napthalene, phenanthrene,
benz(a)anthrencene
Non VolatHes or Partlculate Matter f<10"7 mm mercury vapor pressure)
Larger polynuclear aromatics; chrysene, coronene
Metals; lead, mercury, chromium
Other Inorganics; asbestos, arsenic, cyanides
29
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The APA objectives should be documented and circulated for peer review by
staff members that have knowledge of the site, APA, and the site mitigation
process. The review process may also help Identify site characterization data
needs. Developing site-specific objectives Is an Iterative process; more than
one round of data gathering, review, and discussion may be needed to develop
satisfactory objectives.
3.1.2 Site Scoping
The second step in the development of BEEs 1s collecting available
Information about the site. This should be a quick, straightforward
information search, Involving but not limited to the collection of records,
reports, shipping manifests, newspaper clippings, and Information from
interviews with people living close to or affiliated with the site. For NPL
sites, data should be available from the preliminary assessment and site
inspection conducted prior to Inclusion on the NPL. The type of information
to be collected parallels, for the most part, the factors considered in
creating the objective. These include: :
Source of the waste (type of industry);
Connositlon of the waste (organlc-volatile/semi-organic;
Inorganic-metals, others; biological; radioactive);
Distribution of the waste and cover material limiting volatilization
and uptake of particulate matter from the waste;
Distance from the waste to the property fenceline; and
Representative meteorological data.
30
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3.1.3 Evaluate Available Site Data
The existing site Information should be evaluated to determine the
potential for air pathway contamination. Examples of types of contaminants
and situations to be evaluated are provided in Table 7. If it is determined
through this assessment that the site poses no potential for air pathway
contaminant migration, then no further evaluation of the baseline emissions is
required. The site manager must record the basis for this decision and
include these data in the site Investigation documentation. In most cases,
insufficient Information will be available at this stage, and further work
will be warranted. If air emissions are a potential concern, the next step of
the protocol (site screening study) should be implemented to provide
additional Information to make a judgement regarding the potential for air
emissions from the site. At this point the site-specific APA objectives
should be reviewed to ensure they are still realistic, attainable, and
applicable.
>3.1.4 Design and Conduct the Site Screening Study "*
Designing a site screening study to assess the air emissions potential
involves the selection of an air emissions measurement/assessment technology.
The four broad categories of measurement/assessment technologies include:
Direct emissions measurement;
Indirect emissions measurement;
Air monitoring/modeling; and
Emissions (predictive) modeling.
Each technology can be further categorized according to its level of
complexity as screening (quick and simple) or in-depth (very detailed).
The activities necessary to design and conduct the site screening study
are:
31
-------
TABLE 7. EXAMPLES OF TYPES OF CONTAMINANTS AND SITUATIONS THAT MAY
INDICATE A POTENTIAL FOR AIR PATHWAY CONTAMINATION
Situation/Condition
Participate
Volatile* Matter
Comment
Site Odors, J
Neighborhood
Complaints
Observation of Dust
Clouds During Wind
Evidence of Metal J
Corrosion
Vent pipes J
Seeps of Waste J
Weathered Waste J
Surface
Aged and Layered J
Waste
Aerated Lagoons J
Exposed Waste J
Industrial Wastes J
Petroleum Wastes J
Industrial Wastes/
Paint Wastes J
J
J
J
J
Indicates moderate to high
levels of BEEs.
Check soil cover and look for
waste piles.
Look for corrosive agents.
Check records to determine if
the site 1s a codisposal
facility.
Probable burled wastes.
Emissions of disturbed waste
may be very high.
Likely that volatiles are
higher in underlying lay
chemicals possible.
Increased emissions.
Increased emissions.
Waste mixtures likely, check
for particular solvent types,
aromatic and halogenated
organic solvents.
Tar/wastes with volatile
emissions likely.
Organic volatiles likely.
(Continued)
32
-------
TABLE 7. (Continued)
Situation/Condition
Participate
Volatile* Matter
Comment
Industrial Wastes
Works or Plating
Municipal Wastes
Hospital Wastes
Chemical Product
. Site "Walk-Overs"
. Site "Walk-Overs"
J
J
J
J
Metal-contaminated particulate
matter likely.
Methane/carbon dioxide
volatiles likely; look
Industrial waste.
for
Solvent used likely;
biological hazards and
radioactive waste possible.
High concentrations of
specific chemicals likely.
Gas detection results indicate
the presence of gas species
and the potential for
emissions.
Visual Inspection and particle
counting/detection results
indicate the potential for
particulate matter emissions.
33
-------
Determine the feasibility of obtaining the screening data.
(Identify any site factors that may limit this activity.)
Select appropriate tracer species, screening technologies, and
appl1cab!e equ1pment/1nstrumentat1on.
Design the site Inspection technical approach and test plan,
Including the Quality Assurance/Quality Control Program. Make sure
that all units of a combined site are studied.
Circulate the site screening approach for review and ensure the
screening addresses the site-specific objectlve(s).
Modify the site screening program, as necessary.
Conduct the site screening study and document the findings.
Determine 1f the site screening study was adequate to characterize
the air contamination migration pathway and If detailed BEE data are
necessary. If detailed BEEs are necessary, Initiate the In-depth
site characterization study. If not, document the site inspection
survey results and the basis for discontinuing the APA.
One preliminary step 1s to evaluate those key factors that affect the air
emissions of volatiles and particulate matter. The factors were presented in
Section 2 and are summarized in the check-list presented in Figure 6. This
figure can be used to summarize site information and facilitate the decisions
regarding selecting and Implementing screening technologies. If the site
contains a waste type that has the potential to create air emissions, the most
Important factors which determine the baseline emissions are typically site
conditions and weather conditions. Once the checklist (Figure 6) has been
completed and some knowledge of the factors affecting air emission processes
1s gained, the site manager must select appropriate indicator species and
select air emission screening technologies, equipment, and instrumentation.
34
------- An error occurred while trying to OCR this image.
-------
Indicator species are species found in the waste that can be used to
represent a group of species 1n determining emissions. If little 1s known
about which specific species are present at the site, select an Indicator that
represents a family or class of species so that gross data on emissions can be
obtained and then later refined. Table 8 provides Information that will aid
in this selection process. The Ideal Indicator species or class of species
is:
Present in the air emissions in a fixed ratio;
A non-reactive or stable species;
Present at levels above analytical detection limits;*
Unique to the site (not in background air samples);
Representative of the "worst case" toxicity for compounds at the
site; and
Applicable for existing measurement and monitoring technologies; and
Of known toxicity and exposure criteria.
A 11st of candidate Indicator species can be developed from those species
previously Identified in analysis of the waste or by identifying broad-band
type indicators that represent the type of waste identified in the scoping.
Candidate species should match as closely as possible the characteristics of
an ideal indicator species. The two main required characteristics are
presence in the air emissions from the site and the ability to measure/monitor
the species using commercially available methods and instruments. Examples of
broad-band, class and indicator species are given in Table 9.
36
-------
TABLE 8. FACTORS TO CONSIDER IN SELECTING AN INDICATOR SPECIES FOR STUDY
1) Homogeneity of waste and representativeness of proposed
Indicator species;
2) Variety of types of air contaminants (organic, Inorganic,
blohazard, radioactive);
3) Physical state of air contaminants (gas, liquid, solid);
4) Level of air contaminant emission;
5) APA objectives;
6) Feasibility of air monitoring for proposed Indicator species;
7) Availability of standard sampling/analytlcal/monltorlng
techniques;
8) Potential interferences for the proposed Indicator species;
and
9) Health effects.
37
-------
TABLE 9. EXAMPLES OF BROAD-BAND, CLASS, AND INDICATOR SPECIES
BROAD BAND
Volatile Organ1cs
CLASSES OF COMPOUNDS
Aliphatics
Aromatics
INDICATOR SPECIES
Alkanes, Total
Hydrocarbons as Pentane
Benzene, Xylene, Toluene
Volatile Inorganics
Semi-Volatile Organics
Non-Volatiles
Halogenated Species
Oxygenated Species
Sulfur Containing
Species
Nitrogen Containing
Species
Acid Gases
Sulfur Containing
Polynuclear Aromatics
(PAH)
Polychlorinated
Biphenols (PCBs)
Metals
Trichloroethene,
Trichloroethane, Vinyl
Chloride
Ethanol, Formaldehyde
Mercaptans, Thiophenes
Benzonitrile
Sulfur Dioxide, Hydrogen
Chloride
Hydrogen Sulfide
Napathalene, Benzo-
(a)Pyrene
PCBs As Aroclor 1254
Lead, Chromium, Zinc
38
-------
In addition to selecting Indicator species, the site manager must select
the most suitable air emissions screening technology. Screening technologies
are summarized 1n Table 10 and described in Table 11. A1r emissions
measurement/assessment technologies are described in detail in Section 4. The
four categories of screening technologies are described below.
Direct Emissions Measurement. Concentration measurements can be
made of the air directly above the waste, either the "head space" or
air space of a sampler placed on the waste, or the head space of a
sample bottle half-filled with waste material. The screening
provides a relative measure of the emission potential of various
wastes/locations. High concentrations of volatile species (Ci) in
the head space can Indicate high potential for air emissions from
the site. Likewise, low concentrations can Indicate low potential
for air emissions. The advantage of these screening technologies is
that they are relatively quick, easy and Inexpensive to perform.
They also can have the highest sensitivity (i.e., detect the
contaminants even at low concentrations), since they measure
concentrations at the source. The techniques are only applicable to
volatile gas species. These data can be used to estimate emission
factors to Indicate the potential for air emissions.
Indirect Emissions Measurement. This class of technologies can be
used for any type of contaminant such as volatiles and/or
participate matter. It is probably the most common screening
technology used, though it is usually not used to develop emission
estimates. Screening measurements can be made upwind and downwind
and directly above waste material using real-time instruments to
estimate potential for air emissions. Air concentration
measurements made at short distances (<40 meters) downwind of the
waste can be used to indicate the potential for air emissions from
the site. Downwind measurements should be corrected for any
Instrument bias and upwind interferences. Meteorological factors
39
-------
TABLE ID.' SCREENING TECHNOLOGIES APPLICABLE TO SITE SCREENING APA
FOR LANDFILLS AND LAGOONS*
Direct Emissions Measurement
Head Space Sampler (Refer to 4.1.1)
- Head Space Analysis of Bottled Sample (Refer to 4.1.2)
Indirect Emissions Measurement
- Upwind/Downwind (Refer to 4.2.1)
- Mass Balance (Refer to 4.2.2)
- Real-time Instrument Survey (Refer to 4.2.3)
A1r Monitoring/Modeling
- Upwind/Downwind (Refer to 4.2.1)
Emissions (Predictive) Modeling
Any model using literature values and assumed concentrations,
- Thlbodeaux-Hwang (Landfills)
- Mackay (Lagoons)
*See Section 4 for more detail.
40
-------
TABLE 11. SUMMARY TABLE OF INFORMATION ON THE VARIOUS CLASSES OF ASSESSMENT
TECHNOLOGIES AND SCREENING ASSESSMENT TECHNOLOGIES
Class of or
Assessment
Technology
Application
Advantages
Disadvantages
Direct Emission
Measurement
Head Space
Sampler
Head Space Sample
- in a Bottle
Landfills and
Lagoons,
especially 1f
Identification of
BEEs per unit on
a combined site
Is required.
All landfills;
lagoons (non-
aerated) with
flotation device.
All landfills and
lagoons where you
have a sample of
the waste.
High precision
and accuracy,
measures
undisturbed or
disturbed BEE
without modeling,
can distinguish
between units if
combined site.
Representative of
volatile
emissions
potential.
Rapid Screening
technology that
1s easy to
perform.
Heterogeneous
waste will
require higher
number of
measurement
points for
representative
BEE.
Sampling devices
required.
Can lose a
significant
fraction of the
volatile species.
Indirect
Emission
Measurement
Upwind/Downwind
Larger landfills
and lagoons and
sites with waste
handling
activities,
combined sites.
Landfills and
Lagoons (any area
source).
Assess BEE from
an area source,
regardless of
homogeniety and
site activity.
Can be used for
Inaccessible
sites.
Broadly
applicable and
can provide an
estimate of
emissions.
Limitations
imposed by
modeling,
techniques are
Influenced by
meteorological
conditions, may
not be able to
distinguish
between units of
a combined site
or up-wind
interference.
Single point
ambient
measurements may
not represent the
emission source.
(Continued)
41
-------
TABLE 11. (Continued)
Class of or
Assessment
Technology
Application
Advantages
Disadvantages
Mass Balance
Lagoons and some
landfills.
Real-time
Instrument Survey
Landfills and
lagoons (any area
source).
Limited resources
are required.
Rapid, real-time
data that can be
used to Indicate
emissions
potential.
Requires
concentration
data over time,
Inherent
Insensltlvity due
to low mass of
volatile species.
Highly variable,
quality control
program for
analyzers
required.
A1r Monitoring/
Modeling
Landfills and
lagoons (any area
sources).
Upwind/Downwind
Landfills and
Lagoons (any area
source).
Typically
provides data
that represents
air
concentrations
the community is
exposed to
(fenceline).
Broadly
applicable,
provides
community ambient
concentration
data.
Limitations
Imposed by
modeling,
techniques are
influences by
meteorological
conditions,
analytical
sensitivity may
be a limiting
factor.
Low
concentrations
with high
variability,
measurement
subject to
meteor!ogical
influences.
(Continued)
42
-------
TABLE 11. (Continued)
Class of or
Assessment
Technology
Application
Advantages
Disadvantages
Emissions Landfills and Provide rapid, Accuracy,
(Predictive) lagoons, Inexpensive precision
Modeling especially assessment, dependent on
applications with particularly qulaiyt of site-
site-specific where only a few specific data or
Information. species are of assumptions.
concern. Model Most models have
Inputs can be limited
assumed or taken validation.
from literature
1f site-specific
data is not
available.
43
-------
can Influence the air concentration of volatiles and particulate
matter so field notes must Include on-slte observations and
meteorological conditions during testing.
A1r Mon1tor1no/Modeling. A1r monitoring and modeling technologies
are equivalent to the Indirect emissions measurement technologies
except that the samples are collected at greater distances from the
waste, typically at the fencellne or property line, and the sampling
locations are not as clustered. If meteorological data are
collected concurrently, these data can be used to validate
dispersion model estimates and estimate the potential for
contaminants to reach off-site receptors. However, they may be
limited by the sensitivity of the Instrumental measurement used and
: the dispersion and dilution of the air emission. Unless estimates
of off-site Impact potential are needed, fenceline monitoring is not
recommended for the screening study.
Emissions (Predictive) Modeling. Emissions modeling can be used if
the preliminary assessment has provided fairly detailed Information
that can be Input into a model. The model estimates can usually be
Improved by using air emissions data from the site. The
Thibodeaux-Hwang model 1s appropriate as a screening technology for
landfills, and the Mackay model 1s appropriate for lagoons.
Modeling has the obvious advantage of being an off-site activity.
Once an appropriate screening technology and associated equipment/
instruments are selected, a technical approach to applying the technology
should be developed. The Data Quality Ob.iective For Remedial Response
Activities (13) can provide assistance in designing the site screening.
Again, each unit of a combined site must be studied independently. This may
Involve the use of different screening technologies for the various site
units.
44
-------
' Quality control should be an Integral part of any screening study, and
direction in developing and documenting a quality assurance project plan can
be obtained from the Interim Guidelines and Specifications For Preparing
Quality Assurance Pro.lect Plans.(14) One very useful exercise In the design
of the screening study is a "dry-run" survey, Including a mock exercise
involving data use. This will help in determining if the technical approach
- will satisfy the Intended objective of obtaining an estimate of the potential
- for air emissions from the site.
P
After design 1s completed, the site screening approach should be
circulated for review and then modified, as necessary.
Once the site screening has been completed, the screening tlata should be
evaluated to determine if further data (in-depth measurements) are required
for the site characterization. Screening data may consist of a concentration
-number representing volatile content (headspace sampler or analysis of
headspace above the waste in a bottled sample) or a preliminary BEE (indirect
Remission measurement/model estimate, air monitoring/model estimate, predictive
* model estimate). The equations in Figure 7 show how these data should be
organized. Note that the BEE should be an addition of all of the site units
if the units are studied Individually. Any emissions data for disturbed waste
should not be included in the BEE and do >ot have to be summed separately
since the site mitigation planning will probably use the disturbed site
emission estimates on a unit basis in developing mitigations for "operable
units."
Absolute criteria against which to compare these BEE data are not
available. Estimated ambient levels (determined from the BEEs) can be
compared to state ambient air toxic levels and to EPA cancer risk values if
available.
45
-------
Undisturbed Site BEE
Unit1 Cj (Eq. 1)
Unit! UEEi|t>a (Eq. 2)
where, Unit1 = a waste site or a discrete component of a waste site (com-
bined site with multiple units);
Cj = concentration of species above the undisturbed waste in a
sampler; or concentration of species in the air above or
downwind of the undisturbed waste;
i = species or group of species;
t = time duration of emission measurement;
a = area of exposed waste per unit; and
UEEIi.t.a = site emission estimate for species; for unit U (mass/time-
area) for exposed waste surface (expressed per unit surface
area).
For sites with multiple units, the BEE expression is:
BEE = Unitj Emissions +
Unit2 Emissions + Unit3 Emissions... (Eq. 3)
or
BEE = UlEEi>tta + U2EEittfa + U^^... (Eq. A)
where, UjEE^ t a = undisturbed site emission estimate for Unit*.
Figure 7. Undisturbed site BEE equations
46
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If high levels of air emissions from the site are possible 'and more
detailed Information Is required to meet the APA objectives, then site
characterization should be conducted using 1n-depth technologies to develop
representative BEEs. If, however, little or no potential for air emissions
surfaces from the data or If screening BEEs provide enough Information for a
site manager to evaluate air emissions, In-depth BEEs development may not be
necessary In the site characterization.
t 3.1.5 Design and Conduct the In-Deoth Site Characterization
The activities to design and conduct an in-depth study are similar to
those described in Section 3.1.4 for the screening APA except that in-depth
assessment technologies rather than screening technologies are-used. The
steps are:
Determine the feasibility of obtaining the detailed BEEs.
Select appropriate detailed technologies, indicator species, and
appl1cable equlpment/instrumentat1on.
Design the site characterization technical approach and test plan,
including the QA/QC program.
Circulate the detailed technical approach and test plan for review
and ensure it addresses the site-specific objective(s).
Conduct the site characterization program and document the findings.
Determine if the BEE data are sufficient and adequate for site
mitigation decisions. If adequate, document them; if inadequate,
evaluate the data needs and reiterate, as necessary. Re-evaluate
and document.
47
-------
In-depth-technologies for developing BEEs are summarized In Table 12 and
presented In detail 1n Section 4. Information that may be useful 1n selecting
the appropriate assessment technology 1s summarized 1n Table 13. In general,
direct emissions measurement technologies offer several advantages over the
other technology categories and are considered to be the preferred
technologies for most sites. With the exception of the wind tunnel, the
direct measurement technologies applicable to landfills and lagoons are
limited to volatlles. These technologies generate BEEs as a function of the
site conditions and can be used with a variety of analytical techniques.
Measurements at the source (waste) will be the highest 1n concentration
compared to the other measurement techniques. The direct emission measurement
technologies are not suited to sites that are heterogeneous.
For those applications where the waste Is not homogeneous, 1s
Inaccessible, or consists of multiple sources which need not be individually
studied, the Indirect technologies are preferable to direct technologies.
Total site air emissions can be obtained and used to estimate BEEs and
disturbed waste emission data. Indirect technologies are susceptible to
meteorological Influences and require analytical techniques with greater
sensitivity than those used for direct measurements. Also, upwind
Interferences can create problems.
Air monitoring/modeling technologies are similar to indirect
technologies, but used farther downwind. They have the same applicability and
limitations, except that even lower air concentrations can be expected farther
downwind. This approach is not generally recommended unless fenceline data
are required for other needs. Air monitoring/modeling technologies are
discussed in detail in Volume IV of this series of guidance manuals.
Emissions (predictive) modeling can be used; however, site-specific data,
particularly diffusion coefficient data, are often necessary to obtain
representative BEEs. These data may be difficult and expensive to gather.
48
-------
TABLE 12. -UN-DEPTH TECHNOLOGIES APPLICABLE TO SITE CHARACTERIZATION
FOR LANDFILLS AND LAGOONS
Direct Emissions Measurement
- Surface Emission Isolation Flux Chamber (Refer to 4.1.3)
- Portable Wind Tunnels (Refer to 4.1.4)
- Soil Vapor Probe (Refer to 4.1.5)
- Soil Vapor Monitoring Well (Refer to 4.1.6)
- Downhole Emission Flux Chamber (Refer to 4.1.7)
- Vent Sampling (Refer to 4.1.8)
Indirect Emissions Measurement
- Concentration Profile (Refer to 4.2.4)
- Transect (Refer to 4.2.5)
Ai r Mon1tori ng/Model1ng
- Concentration Profile (Refer to 4.2.4)
- Transect (Refer to 4.2.5)
- Exposure Profile (Refer to 4.3.1)
Emissions (Predictive) Modeling
- Any model using site-specific values
- RTI. (Landfills)
- Thibodeaux, Parker, and Heck (Lagoons)
49
-------
TABLE 13. SUMMARY TABLE OF INFORMAITON ON THE VARIOUS CLASSES OF
ASSESSMENT TECHNOLOGIES AND IN-DEPTH ASSESSMENT TECHNOLOGIES
Class of or
Assessment
Technology Application Advantages
Disadvantages
Direct
Emission
Measurement
Emission
Isolation Flux
Chamber
(Volatiles)
Soil Probe
(Volatiles)
Downhole
Emission Flux
Chamber
(Volatiles)
Landfills and
lagoons, especially
1f Identification
of BEEs per unit on
a combined site Is
required.
Landfills-active,
inactive, soil
contamination,
waste piles;
Lagoons
(nonaerated) with
flotation on
device.
Landfills-active,
Inactive, soil
contamination,
waste piles;
Lagoons-berms
around lagoons,
heavy sludges.
Landfills-active,
inactive, soil
contamination,
waste piles;
Lagoons-berms
around lagoons,
heavy sludges.
High precision
and accuracy,
measures
undisturbed or
disturbed BEE
without modeling,
can distinguish
between units if
combined site.
High precision
and accuracy,
measures
undisturbed or
disturbed BEE
without modeling,
can distinguish
between units if
combined site.
Can obtain a
subsurface
distrubed BEE 1-
to-10 feet below
land surface
without
excavation.
Can obtain a
subsurface
disturbed BEE 1
to 100 feet or
more below land
surface with a
hollow stem auger
drill rig.
Heterogeneous
waste will
require higher
number of
measurement
points for
representative
BEE.
Heterogeneous
waste will
require higher
number of
measurement
points for
representative
BEE.
Heterogeneous
waste will
require higher
number of
measurement
points for
representative
BEE.
Layered or
stratified waste
will require BEE
for each discrete
layer.
(Continued)
50
-------
TABLE 13. (Continued)
Class of or
Assessment
Techno!ogy
Application
Advantages
Disadvantages
Vent Sampling
(Volatlles)
Crack Sampling
(VolatHes)
Wind Tunnel
Measurement
(Volatiles
and/or
Particulate
Matter)
Waste repositories
with passive or
active venting
system, common at
municipal, and co-
disposal landfills.
Covered landfills
or subsurface
contamination.
Special'zed for
particulate
emissions from
waste piles and
solid surfaces,
landfills, lagoons
(non-aerated) with
flotation on
device.
Simple BEE
measurement
procedure.
Identifies gross
estimate of
emissions from
covered
landfills.
BEE for
particulate
matter and/or
volatlles as a
function of wind
speed.
Often difficult
to measure low
gas flow rates
which causes
Imprecision and
Inaccuracy,
include sampling
schedule that
Identifies
ddiurnal
variations/other
fattors that
influence gas
production.
Only provides an
estimate of
emissions rate,
must include
sampling at other
locations to
assess emissions
potential.
Heterogeneous
waste will
require higher
number of
measurement
points for
representative
BEE, additional
support equipment
needed to produce
simulated wind
speed.
(Continued)
51
-------
TABLE 13. (Continued)
Class of or
Assessment
Technology
Application
Advantages
Disadvantages
Indirect
Emission
Measurement
Concentration
Profile
T(Volat1les)
Transect
(VolatUes/
Particulate
Matter)
Larger landfills
and lagoons and
sites with waste
handling
activities,
combined sites.
Assess BEE from
an area source,
regardless of
homogenlety and
site activity.
Can be used for
Inaccessible
sites.
Lagoons, Landfills-
large solid waste
site and
contaminated soil.
Lagoons, Landfills-
large or small
sites.
Specialized
measurement and
modeling
technique, high
precision and
accuracy for an
Indirect
technique.
Specialized
measurement and
modeling
technique, can be
used for
particulate
matter from waste
handling.
Limitations
imposed by
modeling,
techniques are
influenced by
meteorological
conditions, may
not be able to
distinguish
between units of
a combined site
or up-wind
Interference.
Must meet
meteorological
conditions of
technique, not
well suited for
small waste
areas,
sophisticated
support equipment
required.
Must meet
meteorlogical
conditions of
technique,
technique
influenced by
meteorological
conditions.
Air
Monitoring/
Modeling
Landfills and
Lagoons, complete
site emissions,
monitoring at
downwind distances
greater than
Indirect emission
measurements.
Typically
provides data
that represent
air
concentrations
the community is
exposed to
(Fenceline).
Limitations
imposed by
modeling,
techniques are
influenced by
meterological
conditions,
analytical
sensitivity may
be a limiting
factor.
(Continued)
52
-------
TABLE 13. (Continued)
Class of or
Assessment
Technology
Concentration
Application
Not typically used
Advantages
None.
Disadvantages
Modeling may not
Profile
(Volatlles)
Transect
(Volatlles/
Particulates
Matter)
for downwind
measurements.
Lagoons, Landfills
(any waste site or
waste handling
treatment for total
site emissions).
Generally
applicable to
most situations,
predict emissions
from data taken
downwi nd.
Limitations
imposed by
modeling,
techniques are
influenced by
meterological
conditions,
analytical
sensitivity may
be a limiting
factor.
Emissions
(Predictive)
Modeling
(Volatiles/
Particulate
Matter)
AP-42 Dust
Emissions for
Vehicles
(Participate
Matter)
Landfills and
lagoons, especially
applications with
site-specific
Information.
Road Dust
Provide rapid,
inexpensive
assessment,
particularly
where only a few
species are of
concern. Model
Inputs can be
assumed or taken
from literature
if site-specific
data are not
available.
Established EPA-
approved model.
Accuracy,
precision
dependent on
quality of site-
specific data or
assumptions.
Most models have
limited
validation.
Accuracy depends
on quality site-
specific data.
(Continued)
53
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TABLE 13. (Continued)
Class of or
Assessment
Technology
Covered
Application
Covered Landfills
Advantages
Provide rapid,
Disadvantages
Accuracy,
Landfill Models
(Volatlles)
Open Dump
Models
(Volatlles)
Open Landfills
Lagoon Models
(Volatiles)
Lagoons, with or
without generation.
Inexpensive
assessment.
Models can be
selected based on
available input
data. Can
account for bio-
gas generation at
co-disposal
sites.
Account for non-
steady state
emission (i.e.,
declining
emission) over
time.
Provide rapid,
inexpensive
assessment.
Models can be
selected based on
available data.
precision,
dependent on
qualiyt of input
data. Do not
account for
losses to other
pathways.
Accuracy,
precision
dependent on
quality of input
data. Do not
account for
losses to other
pathways. Do not
account for bio-
gas generation.
Accuracy,
precision
dependent on
quality of input
data. Do not
account for
losses to other
pathways. Assume
constant source
strength over
time.
54
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In addition, demonstrating the validity of the models for specific
applications nay be difficult. It Is emphasized that site-specific data are
required for site characterization; the use of literature data should be
limited, if possible.
Once the in-depth site characterization has been designed and conducted,
the BEEs should be evaluated and documented. Data should be organized like
the screening assessment data generating the detailed undisturbed site BEE
(Eq. 4). These equations are Identical to the screening assessment equations
but are generally better estimates of the emissions potential since more
sophisticated technologies are used.
If the baseline emission estimates are considered necessary and
sufficient to satisfy the project needs, then the field studies for the APA
are complete and these data are documented. If the BEEs are considered
inadequate or additional APA data are required, then follow on-site
characterization should be designed and conducted.
3.2 USE OF THE BEEs IN THE MITIGATION PROCESS
Figure 8 Illustrates how the BEEs fit In the CERCLA mitigation process.
Data uses for non-NPL sites will probably be very similar to those identified
in Figure 8. BEEs generated in the remedial investigation can be used in two
ways. First, BEE data provide Information regarding the potential air quality
impact and health risk(s) posed by the site should the no-action remedial
alternative be selected. Essentially, this is the air impact that can be
expected from the site over time if the site is left alone. Thus, the BEEs
used in this way may help justify the decision to mitigate the site. These
data may also indicate the need for an immediate removal action to protect the
public from possible air contaminants.
55
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CD
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UJ
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Second, data for the disturbed site are necessary to estimate short-term
Impacts to air quality and risks to on-slte workers and neighboring residents
during cleanup. These data assist 1n the evaluation of remedial alternatives
considered 1n the feasibility study. Remember that this protocol 1s designed
specifically to develop BEEs (and disturbed emission estimates). These data,
along with dispersion modeling, can be used to assess off-site Impacts to air
quality. Assessing off-site Impacts 1s one of the topics addressed in Volume
IV.
57
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SECTION 4
AIR EMISSION MEASUREMENT TECHNIQUES
Section 4 describes recommended air emission assessment technologies for
landfills and lagoons. The recommended technologies are organized into four
generic categories: direct emission measurement technologies, indirect
emission measurement technologies, air monitoring/modeling technologies, and
emissions (predictive) modeling technologies. Each category is further
divided Into two classes: screening technologies, and in-depth assessment
technologies. The screening technologies provide some level of air emission
assessment but may not accurately represent the site's potential for air
emissions. The in-depth assessment technologies are much more rigorous and
generally provide a more accurate estimate of the potential for air emissions
from the site. Screening technologies are typically used in the site
inspection stage of the RI, whereas in-depth assessment technologies are
typically used during site characterization.
Where possible, "preferred" technologies are identified and recommended
for use. However, the preferred technology will not always be the best choice
of assessment technology for every application. The intent of identifying
preferred technologies is to assist the RPM or site manager by identifying
those technologies that are preferable from a technical standpoint for the
majority of sites.
4.1 DIRECT EMISSION MEASUREMENT TECHNOLOGIES
A general discussion of direct measurement technologies is followed by
.descriptions of the individual techniques. The direct emission measurement
technologies presented in this section are:
Screening Technologies
4.1.1 Head Space Sampler
4.1.2 Head Space Analysis of Bottled Sample
58
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In-Depth Technologies--
4.1.3 Emission Isolation Flux Chamber
4.1.4 Portable Wind Tunnels
4.1.5 Soil Vapor Probes
4.1.6 Soil Vapor Monitoring Well
4.1.7 Downhole Chamber
4.1.8 Vent Sampling
Direct emission measurement technologies are often the preferred
technologies for investigating the air pathway. The technologies generally
consist of isolating or covering a small section of the site surface or
subsurface using a chamber or enclosure. The concentration of emissions
produced by the isolated surface is measured within the chamber or from an
outlet line. These concentration measurements, along with other
technology-specific parameters, are then used to calculate an emission flux or
relative concentration valve. The emission flux (rate per area) can generally
be related to an emission rate for the entire source.
The types of volatile or particulate species that can be measured by the
technologies are essentially unrestricted; their measurement depends on the
sampling media selected and analysis' technique rather than the emission
"measurement technology. However, few of the technologies are applicable to
both volatile and particulate emission rate measurement. Selection of
sampling media and analysis techniques is outside the scope of this document,
but is addressed in Volume IV of this series. The direct emission measurement
technologies can be used to determine the emission rate variability of afsite
by performing multiple measurements at selected locations across the site. In
addition, these technologies allow for the evaluation of individual waste
areas at the site so that the investigation can focus on those areas with the
greatest potential emissions.
The cost of the direct emission measurement technologies varies
considerably. However, most of the technologies are cost-effective, allowing
for several measurements in a given day. Real-time instruments can be used
with all the direct technologies to provide immediate data for decision-making
59
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during the sampling program, and for the relative ranking of the emission rate
at locations across the site. This procedure can be used to reduce the number
of samples requiring laboratory analysis by screening for those samples with
significant concentrations.
Direct emission measurement technologies, as a class of assessment
technologies, are generally preferable to other classes of technologies
because they have been proven to be a cost-effective approach for obtaining
emission rate and concentration data and they avoid the necessity of modeling
to develop BEEs. 'Direct emission measurement technologies and equipment -are
generally relatively simple and straightforward.
4.1.1 Head Space Samplers (Screening Technology)
Head space samplers are in-situ screening technologies that use a chamber
,to isolate part of the emission source surface.(15,16,17) The quantity or
concentration of vapors and/or gas emitted from the surface that build up in
the chamber over a period of time is measured, rather than measuring a rate.
The head space sampler technology was a predecessor to the emission isolation
flux chamber described in 4.1.3.
Head space samplers may be operated in one of two modes, referred to as
static and dynamic modes. In the static mode, the sampling enclosure is
placed over the emitting surface for a given period of time.(15) The
enclosure may be purged initially with clean air or nitrogen. Surface
emissions then enter the chamber from the exposed surface and are all owed-to
concentrate in the chamber before sample collection.
A time-integrated emission flux for the static mode is calculated as:(15)
Ei - (C, VE)/(t A) (Eq. 5)
where E, - emission flux for component 1 (ug/m2-sec);
C, - concentration of component 1 (ug/m3);
^VE volume of the ..enclosure (m3);
60
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-\ length of time enclosure 1s 1n place (sec); and
A - surface area enclosed by chamber (m2).
The build-up of gas species within the chamber Improves the sensitivity
of the method relative to ambient air sampling. However, the accuracy of the
calculated emission rate 1s dependent on the duration of sampling relative to
-the time required to reach steady-state concentrations within the chamber.
For long sampling periods, the concentration gradient of the soil/air
interface 1s reduced and the emission flux 1s underestimated. Also,
Instantaneous changes in the flux cannot be measured.
In the dynamic mode, the sampling enclosure also is placed over the
emitting surface for a given time period and the chamber may be* initially
purged with clean air or nitrogen. However, collected emissions are
continuously withdrawn from the enclosure.(15) The chamber can be operated
with a second port allowing ambient air to enter the chamber to prevent a
negative pressure within the chamber. The emitted species is concentrated on
sampling media or may be continuously monitored. When the sample is
concentrated on the sampling media (i.e., sorbent), the emission flux is
calculated as:(15)
E, (C, VS)/(A t) (Eq. 6)
where Ei - emission flux for component i (ug/m2-sec);
C, - concentration of component i (ug/m3);
Vs - total volume of sample withdrawn (m3);
* t - length of sampling interval (sec); and
A - surface area enclosed by chamber (m2).
An advantage of the dynamic mode is that the sampling duration and air
sampling rate can be varied to adjust the volume of air sampled in order to
achieve the required analytical sensitivities. The disadvantage of operating
in the dynamic mode is that as the atmosphere within the enclosure is
withdrawn, the emission flux value may be affected. This can occur by the
addition of bulk flow of the soil gas Into the chamber or, alternately, air
61
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entrapment occurring within the enclosure because of leakage at the
enclosure's bottom edge, or by air moving through the soil at the enclosure's
bottom edge. If a second port 1s used to allow atmospheric air to enter, a
means of removing volatlles from the atmospheric air must be used.
The major advantage of the technology Is that the emissions process does
? not have to be fully evaluated to employ the technology. Determining whether
the emission rate 1s controlled by diffusion through the soil cover,
volatilization at the surface/air Interface, etc., to employ the technology is
not necessary. Site-specific conditions, such as depth of soil cover or'soil
porosity, do not have to be determined to employ the technology. Although
desireable, knowledge of the waste composition and exact spacial boundaries of
the waste are not necessary to use the technology to assess the air pathway.
However, both of these factors will help 1n the selection of appropriate
emission concentration measurement instruments or sampling techniques and the
-.selection of sampling locations.
4ppl1cability--
The emission Isolation flux chamber Is preferred to head space samplers
except where the emission flux is expected to be extremely low. Under these
conditions, use of head space samplers in static mode for long intervals
(possibly days) may allow emission fluxes to be measured by the head space
sampling technology where other technologies may fail to produce a measurable
emission flux.
Head space samplers are applicable to emission flux measurement from all
forms of solid area sources including landfills, open dumps, and waste piles,
and for homogenous, quiescent lagoons. The technology can be used at open and
closed landfills, with or without internal gas generation. The technology can
be used to assess emission rates from cracks in the surface cover and from
vents that have minimal or no volumetric flow. The technology is applicable
both for undisturbed and disturbed site conditions.
62
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Llnritatlons--
As previously mentioned, head space samplers may enhance (dynamic mode)
* or suppress (static mode) the emission flux. The dynamic mode also may be
subject to air entrapment resulting in deceptively low emission flux values.
The technology does not assess the effects of wind speed on the emission flux.
For lagoons, removal of air from the chamber will induce a pressure change
unless make-up air 1s able to enter the chamber. The chamber will require
some type of support of flotation system, and this may be affected by waves or
agitation.
Head space samplers are not applicable to the measurement of particulate
emission fluxes. Also, the technology has not been reported as a validated
technology.
3
4.1.2 Headsoace Analysis of Bottled Samples (Screening Technology)
Headspace analysis of bottled sample is a preferred technology for field
screening of wastes and soils to determine their relative emissions potential.
In this method, liquid, soil, or waste from the site surface or subsurface is
collected. The material 1s Immediately placed in a sampling container,
,.typically 1-liter or a 40 ml volatile organic analysis (VOA) vial with septa;
and the container sealed. Transferring the soil or waste immediately after
Collection Into the sample container to prevent loss of volatiles is the key
'to successful use of the technology. The container is allowed to stand for a
given period of time, typically 5 to 30 minutes. The container lid is then
cracked open and the probe of a field Instrument is inserted to determine if
^soil-vapors are present. Syringes can be used to withdraw gas samples via
parts of the VOA vial septa for more sophisticated analysis techniques.
Typical field instruments used include portable flame ionization detectors,
photolonization detectors, combustion meters, and colorimetric tubes.
A second type of headspace analysis involves analyzing the headspace gas
or extracted solids of a soil waste core. To obtain a sample to measure the
headspace, an undisturbed core 1s collected using an auger or by driving a
63
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tube Into the ground. The sample 1s then sealed 1n a sample container with
minimal headspace.
The core sampler shown In Figure 9 consists of a brass core sleeve which
1s pressed Into the soil to a sufficient depth to fill the sampler but not
compress the sample. After excess soil is removed, the sleeve is sealed with
a Teflon-lined cap. The samples are stored at room temperature. Headspace
gas is removed from the core by a syringe and analyzed by GC.
Appl 1 cablli ty-
The headspace analysis is an excellent screening technology for all types
of soil or waste which have a volatile component. Some experimentation may be
required to determine the optional time to allow for volatilization to occur
before measurement. The technology can be used to identify surface
contamination boundaries, select sampling locations for detailed technologies,
and identify health and safety concerns.
'Limitations--
The technology does not provide for calculation of an emission rate, but
rather Identifies soils and wastes which are potential source of air
emissions. The technology generally only provides qualitative data on species
type, however, species specific data can be obtained if suitable analytical
techniques are selected. The technology is not applicable to particulate
emissions.
The technology is best suited for measuring adsorbed organics, although
it can also be effective with free organics in the pore space if the material
is rapidly transferred to the sample container, or if tube or core samplers
are used.
Preferred Technology--
Headspace analysis of bottled samples is one of the two preferred
technologies for the emission screening study. This direct approach is
preferred because 1t 1s simple to Implement and effective at identifying
volatile content, which represents volatile emissions potential. Chemical
64
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-WING NUT
END CAP
SCREENS
THREADED ROD
I BRASS CORE SLEEVE)
TEFLON RING
TEFLON CAP LINER
Figure 9. Schematic diagram of.a soil core sample sleeve.
65
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analysis of the waste will Identify the potential for contaminated participate
matter emissions. Thus, the headspace analysis and the analysis of the waste
can provide effective screening of emissions potential. The other preferred
screening technology is an indirect technology, simple upwind/downwind
sampling.
4.1.3 Emission Isolation Flux Chamber (In-Deoth Technology)
The emission Isolation flux chamber Is one of the preferred in-depth
technologies for the direct measurement of volatile species emission
rates.(18-23) The technology uses a surface enclosure (flux chamber) to
isolate a known surface area for emission flux (rate per area) measurement.
The emission Isolation flux chamber for solid surfaces is illustrated in
Figure 10 and for liquid surfaces in Figure 11.
Emissions enter the open bottom of chamber from the exposed surface.
Clean, dry sweep air is.added to the chamber at a metered rate. Within the
chamber, the sweep air is mixed with emitted vapors and gases by the physical
design of the sweep air Inlet. The sweep air creates a slight wind velocity
at the emitting surface, preventing a build up of the emission concentration
in the boundary layer directly above the surface. The exit port is used for
measurement of the concentration of the air with the chamber or for sampling
and subsequent analysis. A pressure relief port in the enclosure prevents
pressure build up within the chamber that might otherwise occur when sampling
liquid surfaces. A positive or negative pressure in the enclosure could
affect the emission event and, thus, the assessment of the emission flux. For
lagoons, a support or flotation system is necessary.
The technology directly measures essentially an instantaneous emission
flow (flux) from that surface. The emission flux is calculated from the
surface area isolated, the sweep air flow rate, and the emission
concentration. Statistical methods are used to determine the number of
measurement locations required to characterize the emission from an area
source. These methods are based on the surface area of the source and the
variability (precision)-of the measured emission rate at randomly selected
66
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TEMPERATURE
READOUT
THERMOCOUPLE
SYRINGE/CANISTER
SAMPLING PORT
REAL TIME
ANALYZER
CARRIER
GAS
OUTLET LINE
STAINLESS STEEL
OR PLEXIGLAS
CUT AWAY TO SHOW
SWEEP AIR INLET LINE
AND THE OUTLET LINE
Figure 10. A cutaway diagram of the emission isolation flux chamber
and support equipment.
67
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TEMPERATURE
READOUT
THERMOCOUPLE
PLEXIGLASS
SAMPIE COLLECTION
AND/OR ANALYSIS
GRAB SAMPLE
PORT
\CONTROL
/ VALVES
PERFORATED
OUTLET LINE
SWEEP AW INLET LINE
AND THE OUTLET LINE
Figure 11. A cutaway diagram of the surface emission isolation flux chamber
and support equipment for liquid surfaces.
68
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locations across the site. Use of the emission Isolation flux chamber Is
described 1n the draft "Measurement of Gaseous Emission Rates from Land
'"'Surfaces Using an Emission Isolation Flux Chamber User's Guide (23)." The
emission Isolation flux chamber was validated for EPA (using standard methods)
for measuring volatile emissions from landfills.(22,23)
The emission flux 1s calculated as (23):
E, - (C, Q)/A (Eq. 7)
where E, - emission flux of component 1 (ug/m2-min);
C{ » concentration of component 1 at chamber outlet (ug/m3);
Q - sweep air flow rate into chamber (m3/min); and
A - surface area enclosed by chamber (m2).
Appl 1 cabill ty~
The emission isolation flux chamber is applicable to emission flux
measurement from all types of area sources Including lagoons, landfills^pen
dumps, and waste piles. The technology can be used at open and closed
landfills, with or without internal gas generation. The technology can be
used to assess emission rates from cracks in the surface cover and from vents
that have minimal or no volumetric flow.
The technology is applicable both for undisturbed and disturbed site
^conditions, and for the testing of emissions control technologies. The .
technology can be used to satisfy data needs for all phases of the RI/FS *
^process, as well as post-remediation monitoring and, therefore, can provide
directly comparable data throughout the process.
Umitations--
The emission fluxes of volatile species may be enhanced or suppressed
since the flux chamber alters the environmental conditions (e.g., wind speed)
at the sampling locations. The technology does not assess the effects of wind
. speed on the emission rate.
69
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The technique 1s not particularly well suited to large emission sources
with a high degree of heterogeniety. Comparison of sample data and
variability estimates can determine the number of sampling locations needed to
determine representative area emissions. Also, the technique is not
applicable to the measurement of part icul ate emission fluxes.
^Preferred Techno! ogy--
The emission isolation flux chamber Is a preferred technology for
developing in-depth BEEs. As discussed, the advantages generally out-weigh
the limitations of the technique. The technique is well documented in the
user's guide and well characterized.
4.1.4 Portable Wind Tunnels (In-Deoth Technology)
Wind tunnels are 1n-depth technologies used to directly measure the
emission rate of credible material. They also can be used to measure the
emission flux of volatile compounds. In either application, measurements can
be made under varying wind conditions to examine the effect of wind speed Ion
remissions. The required equipment consists of portable, open-bottomed
enclosures used to Isolate a known surface area, a blower used to simulate
conditions, and sampling devices.
The Cowherd wind tunnel, shown in Figure 12 is a portable wind tunnel
developed for "in situ measurement of emissions from representative test
surfaces under predetermined wind conditions"(24). The tunnel was developed
to measure particulate matter emissions from open waste piles. "The ^
open-floored test section of the portable wind tunnel is placed directly over
the surface to be tested. Air is drawn through the tunnel at controlled
velocities. The exit air stream from the test section passes through a
circular duct fitted with a sampling probe at the down-stream end. Air is
drawn through the probe Isokinetically by a high-volume sampling train"(24).
The sampling train consists of a trapper probe, cyclone precollector,
parallel-slot cascade Impactor, backup filter, and high volume motor. Air
flow is provided by a blower located downstream of the sampling train.
70
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Figure 12. Illustration of MRI wind tunnel
71
-------
The authors state that, "although a portable wind tunnel does not
generate the larger scales of turbulent motion found in the atmosphere, the
turbulent boundary layer formed within the tunnel simulates the smaller scales
of atmospheric turbulence. It is the smaller scale turbulence which
penetrates the wind flow in direct contact with the pile surface and
contributes to the particle entrainment mechanisms"(24).
The emission flux is calculated from the isolated surface area, emission
concentration, simulated wind speed, and time period during which particulates
are collected. Because the emission concentration is collected over time, the
technology measures the overall (time integrated) emission rate rather than
the emission flux. Varying the simulated wind speed between measurements
allows for development of a weighted average emission rate. Th-is is preferred
to using an average wind speed because the total erosion may be greatly
influenced by infrequent periods of high wind speed.
The loss of erodible material is calculated as (24):
E< - (C, Q t)/A (Eq. 8)
where E, - emission rate of component i (g/m2);
C1 » average particulate concentration of component i in tunnel
exit stream (g/m3);
Q - tunnel flow rate (m3/sec);
t - duration of sampling (sec); and
A exposed test area (m2).
Elimination of the time factor in the calculation will provide an
emission flux on a unit area per time basis (g/m2-sec). The average
particulate concentration (C,) may be reduced to account for background dust
levels by sampling under light wind conditions and subtracting the resulting
average concentration from C, values generated during simulations of higher
wind conditions.
72
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The Astle wind tunnel, shown 1n Figure 13, 1s a form of surface enclosure
developed for "measurement of odor source strength"(25); but 1t also may be
applicable to volatile emissions measurement. This portable wind tunnel
consists of an open-bottom enclosure that 1s placed over the emitting surface.
Ambient air 1s blown through the chamber at typical wind speed rates (e.g., 1
to 15 mph) and collected near the enclosure outlet. Test results for volatile
emission rate measurement were not Identified in the literature.
The emission flux 1s calculated from the simulated wind speed, emission
concentration, and surface area Isolated. Varying the wind speed between
measurements allows for development of a weighted average emission rate. The
measurement is essentially instantaneous.
*
The emission flux calculation 1s (25):
E, -
-------
Mwk TMct
cttf^nlitwt
Figure 13. Schematic of portable wind tunnel.
74
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4.1.5 Soil Vapor (Ground) Probes (In-Deoth Technology)
Soil vapor or ground probes are a preferred 1n-depth technology for
mapping the horizontal extent of soil gas plumes in near-surface soils
(26,27,28). The technology directly measures the emission rate potential from
a small area of exposed subsurface soils. One variation of a ground probe is
shown in Figure 14. Probes with small chambers or openings at the probe end
have also been used (see Figure 15). Reference 27 Includes descriptions of a
wide variety of ground probe designs.
The probe assembly is driven into the ground to the desired sampling
depth. Emissions enter the probe from the exposed subsurface soil, depending
on the design via existing openings or by raising the pipe away from the drive
tip. Generally, either a small aliquot of soil gas is collected to avoid
disturbing the soil gas equilibrium or a known amount of soil-gas is pumped
from the probe. The concentration measured is used as a relative indicator of
contamination and potential emissions. Clean, dry sweep air can be added to
the probe at a metered rate if a relative emission "flux" is desired. No true
flux can be measured since the exact surface area of exposed waste is not
known.
The major advantage of the technology is that it allows for rapid mapping
of the horizontal extent of soil gas plumes in near-surface soils. Generally,
v
'mapping is performed by measuring the soil gas concentration without use of
sweep air. The mapping can be used to determine the approximate subsurface
boundaries of buried waste or immiscible liquids floating on the water table.
Ground probes are very useful for investigating the migration of soil vapors
as part of the air pathway analyses.
It is not necessary, although desirable, to know the waste composition to
use the technology. Knowing the waste composition will help in the selection
of appropriate instrumentation or sampling apparatus.
75
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two A* C
0.25 in. Teflon co«t*d at**!
pip* 6 ft Motion
Driving: Tip di«a«c«r Is s«a* M
plp« 0.9. Sh«p* e*nt*rs
tip durlni driving
' Mil catty to pip*
SAMFLISC: Tub* t* rali«d 2 in.
to acc**t toil
vaper<.
Figure 14. Schematic diagram of a simple ground probe.
76
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syringe
3 way valve
Tenax GC trap
fitting
pounding plate
pipe
tubing
coupling
air holes
point
Figure 15. Ground probe design with minimal Internal volume.
77
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Appll cabin ty--
The technology can be used to map soil gas plumes to Indicate approximate
waste boundaries or soil gas migration routes. Ground probes are also
applicable to the measurement of potential volatile emissions from disturbed
subsurface soil and waste. The technology measures the emissions that would
occur 1f the subsurface soil or waste were disturbed by excavation. The
technology also can be used to measure the soil gas concentration by operating
the probe without sweep air. Soil gas concentration measurements can be used
as an Input to predictive models, as discussed 1n Section 4.4.
The technology Is applicable for estimating emissions from solid waste
sites, Including open and closed landfills, with or without internal gas
generation, open dumps, and waste piles. The technology also can be used to
estimate emissions below the edges of tanks, buildings, ponds, etc., by
driving the probe into the soil at an angle. In addition, ground probes can
be hand- or machine-driven. Hand-driven probes allow measurements to be
performed in areas where surface access by machines 1s not available.
Limitations--
Ground probes do not measure the undisturbed emission rate or flux from a
waste site. Rather, the technology measures the potential emissions that
would occur during site disturbance.
Use of ground probes is generally limited to near-surface soils,
typically less than 12 feet deep. However, the operational depth will depend
on site and equipment characteristics which limit the ability to insert the
probe. Ground probes do not measure particulate emission rates.
4.1.6 Soil Vapor Monitoring Wells fln-Deoth Technology)
Soil vapor monitoring wells (29) are used to measure the emission flux
from subsurface soil and waste and to monitor soil vapor concentrations and
the effects of soil vapor remedial actions. The in-depth technology uses a
monitoring well consisting of a screened chamber installed during drilling
activities. As such, the soil vapor monitoring well is a permanent or
78
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semi-permanent structure. Figure 16 illustrates a typical soil vapor
monitoring well.
Soil vapor monitoring wells are installed through the annul us of a
hollow-stem auger. The well consists of an enclosed, screened chamber with
sampling lines leading to the surface. The chamber is enclosed in a sand
pack. The well casing is used to provide support during well construction and
protection for the sampling lines, but soil vapors and gases do not contact
the well casing. Soil vapors and gases enter the soil vapor monitoring well
through the chamber screen. Within the chamber, the vapor and gases are mixed
with clean, dry sweep air. The resulting mixture is withdrawn through the
exit port to measure the emission concentration and/or for sampling and
subsequent analysis. The sweep air flow rate is selected to approximate the
instrumentation or sampling apparatus flow rate.
Because the measured emission concentration is directly related to an
emissions event from an isolated surface over an essentially instantaneous
time period, the technology can be used to estimate the emission flux from the
isolated soil surface. The estimated emission flux is calculated from the
assumed surface area isolated, the sweep air flow rate, and the emission
concentration.
The emission flux is calculated as (26):
E, - _£l? (Eq- 10)
A
where E1 - emission flux for component i (ug/m2-min);
C1 - concentration of component i (ug/m3);
Q sweep air flow rate (m3/min); and
A - exposed surface area (m2) - *dh
d « screen diameter (m); and
h - height of sand pack (m).
Typically, soil vapor monitoring wells are used to measure the soil vapor
concentration, rather than the emission flux. The soil vapor concentration is
measured by operating the well without sweep air.
79
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Figure 16. Vapor monitoring well constructions. (Not to scale)
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The technology Is not dependent on knowledge of the emissions process or
the waste composition, although knowledge of the waste composition will help
In selecting appropriate Instrumentation and/or sampling apparatus.
Applicability--
Soil vapor monitoring wells are applicable to the estimation of the
potential emission flux from subsurface soil and waste. The technology does
not measure the undisturbed emission flux, but rather estimates the emission
flux that would occur during site disturbance. Therefore, the technology is
suitable for determining emissions potential for remedial alternative
evaluation. Soil vapor monitoring wells also are applicable to the monitoring
of soil vapor concentrations and vapor migration, and are the preferred method
for monitoring the effects of soil vapor extraction systems.
The technology is applicable to the estimation of emission fluxes and
concentrations from open and closed landfills, with and without internal gas
generation, and open dumps. The technology also is applicable to measurement
of emission concentration from immiscible liquids floating on the water table.
Limitations--
Soil vapor monitoring wells do not measure the undisturbed emission flux,
but rather the flux that would occur during site disturbance. The technology
1s not applicable to the measurement of particulate emission fluxes.
Determining the actual exposed surface area is an assumed or estimated value.
4.1.7 Downhole Emissions Flux Chamber (In-Depth Technology)
The downhole emissions flux chamber is one of the preferred in-depth
technologies for direct measurement of potential volatile emissions from
subsurface soils (30). The technology uses a flux chamber to measure emission
fluxes from subsurface soils exposed by drilling operations. The chamber
isolates a known area of soil at a desired depth within the annulus of a
hollow-stem auger. Figure 17 depicts the downhole emissions flux chamber. *m
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0.25 in. in
UNE. TEFLON
7 in. length of
TEFLON nusi "~"*>
GLASS
END
suwoirr
CABLf
/
/I
t
0.25 in. outout
LINE. TEFLON
WEIGHTS
Figure 17. Schematic diagram of the downhole emissions flux chamber.
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Emissions tenter the chamber from the exposed surface. Clean, dry sweep
air 1s added to the chamber at a metered rate. Within the chamber, the sweep
air Is mixed with emitted vapors and gases by the physical design of the air
Inlet. The mixture of sweep air and emitted vapors and gases 1s withdrawn
through the exit port for measurement of the emission concentration or for
sampling and subsequent analysis. The sweep air flow rate must match the flow
rate of the analytical Instrumentation or sampling apparatus that 1s used to
withdraw sample gas.
Because the measured emission concentration 1s directly related to an
emissions event from an Isolated surface over an essentially instantaneous
time period, the technology directly measures the emission flow (flux) from
the surface. The emission flux 1s estimated from the assumed surface area
exposed, the sweep air flow rate, and the emission concentration.
The emission flux is calculated as (30):
. E, -_. (Eq. 11)
A
where E, - emission flux of component i (ug/m2-min);
C, - concentration of component 1 (ug/m3);
Q sweep air flow rate (m3/«irin); and
A » exposed surface area (m2).
The major advantage of the technology 1s that it allows the investigation
of subsurface areas without excavation.
Although desireable, knowledge of the waste composition is not necessary
to use the technology to assess the air pathway. However, knowledge of the
waste composition will help in the selection of appropriate emission
concentration measurement Instruments.
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*
Applicability
The downhole flux chamber Is applicable to measurement of the potential
emissions from subsurface soil and waste. The technology estimates the
emission flux that would occur if the subsurface soil or waste were exposed by
excavation. Therefore, the technology is most suitable for determining
emissions potential for remedial alternatives evaluation and/or site
/ disturbances. The technology also can be used to measure the soil gas
concentration by operating the chamber without sweep air. However, for
shallow depths, ground probes are preferred for gas concentration measurements
(see Section 4.1.5).
The technology 1s applicable for estimating emission fluxes from all
materials that can be investigated using hollow-stem auguring techniques. The
technology can be used at open and closed landfills, with or without internal
gas generation, and at open dumps.
Limitations--
The downhole emissions flux chamber does not measure the baseline
emission flux from a waste site. Rather, the technology measures the
potential emission rate that would occur during site disturbance.
The emission flux of volatile species may be enhanced or suppressed if
the sweep air flow rate does not closely match the flow rate of the sample gas
extraction system. The downhole flux chamber cannot be used to measure
particulate emission rates.
Preferred Technology--
The downhole emissions flux chamber is a preferred technology for
developing emissions estimates for subsurface disturbed waste. Most
investigations Involve subsurface sampling using a hollow-stem auger and drill
rig and downhole flux chamber work can be incorporated in the Investigation.
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4.1.8 Vent Sampling (In-Depth Technology)
Vent sampling for emissions measurement have been well documented
elsewhere (32), and will not be discussed 1n detail here. Vent sampling Is
performed when the waste site contains vents with measurable flow rates (I.e.,
active venting, not passive venting), such as vent systems at some landfills.
The In-depth technology requires measuring the emission concentration and the
volumetric flow rate, typically as the exhaust velocity and cross-sectional
area of the vent. Volumetric flow rates for vents (or ducts) can be obtained
using the procedures given 1n 40 Code of Federal Regulations (CFR) Part 60.
Those procedures indicate how to determine the exhaust velocity and
appropriate sampling location. The emission rate for a vent 1s calculated as
(31):
E, - C, U A (Eq. 12)
where E1 emission rate of component i (ug/sec);
C, - concentration of component 1 (ug/m3);
U -gas velocity through vent (m/sec); and §
A - cross-sectional area of vent (m2).
Applicability-
Vent sampling is applicable to any waste site that contains active or
passive venting systems. However, active venting systems are not typical of
uncontrolled hazardous waste sites. Vent sampling can be applied to landfill
vents, tanks, building vents, machinery, and equipment. Where present, vents
may be a major source of air emissions from the site. ,,;
Limitations--
Vent sampling using standard stack sampling technology is not applicable
when the vent has minimal or no flow. For these situations, the emissions
Isolation flux chamber technology 1s preferred, provided that the chamber's
cross-sectional area is larger than the vent's. When the vent is too large
for use of the flux chamber, emission rate estimates may be based on head
space concentration measurements at the vent outlet and diffusion in air
modeling.
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4.2 INDIRECT EMISSION MEASUREMENT TECHNOLOGIES
A general discussion of Indirect measurement techniques 1s followed by a
description of specific techniques. The Indirect emission measurement
technologies presented 1n this section are:
Screening Techno!ogies--
4.2.1 Upwind/Downwind
4.2.2 Mass Balance
4.2.3 Real-Time Instrument Survey
In-Depth Techno!ogies--
4.2.4 Concentration-Profile (C-P)
4.2.5 Transect
4.2.6 Boundary Layer Emission Monitoring
Indirect emission measurement technologies generally consist of measuring
.the atmospheric,concentration of the emitted species and then applying these
data to an equation (air model) to determine the emission rate. Many of the
equations were developed to determine downwind concentrations resulting from
stack emissions. For area emission sources, the source is treated as a
virtual point source or line source.
The in-depth technologies are very similar as all involve clusters of
ambient air samplers. The C-P technique Involves a vertical array of samplers
directly over the source. The transect technique involves vertical and
horizontal arrays of samplers within the downwind plume. The boundary layer
technique 1s a simplified version of the transect technique and involves
several downwind samplers each at a different height.
A disadvantage of indirect emission measurement technologies is that the
results are highly dependent on meteorological conditions. The Indirect
technologies require meteorological monitoring to properly align the sampling
systems and to analyze the data following sample analysis. Changing
meteorological conditions significantly affect the efficiency of collecting
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1"
useful data. Unacceptable meteorological conditions may Invalidate much of
the data collected, requiring an additional sampling effort. The technologies
also may produce false negative results 1f the emitted species are present In
low concentrations which are below the sampling and analysis detection limits,
or 1f upwind sources cannot be fully accounted for. The technologies also may
not be feasible at some sites where the source area 1s excessively large, or
where Insufficient space exists downwind of the source to set up the sampling
array without disturbance of the air flow pattern by obstructions (e.g.,
buildings, tanks).
The types of volatile and particulate species that can be measured by the
technologies are essentially unrestricted, they depend on the sampling media
selected and analysis technique rather than the emission measurement
technology. Sampling media and analysis techniques are not discussed here.
Indirect emission measurement technologies generally do not provide
significant data on the emission rate variability for different locations
across a site. This 1s because the emission concentration is measured
downwind of the site after some atmospheric mixing. The technologies
generally do not allow for the evaluation of individual contaminated areas at
the site unless the areas are separated from one another and are not located
upwind of one another.
{
The costs of the indirect emission measurement technologies vary
considerably. The screening technologies are relatively simple and
straight-forward to implement, and require minimal labor and analytical costs.
7 The in-depth technologies are complex and require considerable equipment,
labor, and analysis costs. All of the technologies are subject to data loss
or sampling delay due to Inappropriate meteorological conditions.
4.2.1 Upwind/Downwind (Screening Techno!oovl
The upwind/downwind technology is an Indirect screening technology (33).
As the name Implies, in this approach one or more monitors are located upwind
of the area source and a second monitor or set of monitors are located
-------
downwind. The monitoring stations Include detectors or samplers for the
species of Interest as well as devices for measuring wind speed and direction.
The upwind monitor serves as a blank or background sampling location.
Concentration 1s measured primarily along the downwind axis only. The average
surface emission flux for a particular trajectory 1s equal to the Increase In
column concentration (downwind minus upwind) divided by the transit time
across the source. Transit time Is a function of the distance between the
source and downwind location, and the average wind velocity.
E.R.1 - (CD-CU) KO az 0 (Eq. 13)
..2
where E.R.1 - emission flux of species (ug/m -sec);
*o
CD - downwind concentration of species 1 (ug/m3);
Cy » upwind concentration of species 1 (ug/m3);
* - 3.141 ...
oy - lateral extent of Gaussian plume;
az « vertical extent of Gaussian plume; and
U - mean wind speed (m/sec).
Applicability--
The upwind/downwind technology is applicable to emission flux measurement
from all forms of area sources, including lagoons, landfills, open dump, and
waste piles. The technology can be used at open and closed landfills, with or
without Internal gas generation. The technology.is applicable both for
undisturbed and disturbed site conditions, and for testing emission control
technologies. The technology can be used for both volatile and particulate
emission flux assessment.
Limitations--
Upwind/downwind requires that meteorological conditions during sampling,
particularly wind speed and variability, match the predetermined conditions
used to select the sampling locations. The sampling locations must be on the
approximate plume centerline.
-------
The technology also assumes that the site Is fairly homogeneous and
that the plume Is well mixed at the downwind sampling location. Therefore,
the technology may not be applicable to heterogeneous sites. The technology
also may not adequately collect emissions from point sources within an area
source, such as cracks in landfill covers or vents, unless the plume 1s well
mixed at the downwind sampling location. The technology 1s not applicable
during quiescent or unstable wind conditions, and may produce false negative
results during these conditions.
Preferred Technology
The upwind/downwind screening technology 1s a preferred indirect
assessment technology. The technology 1s similar to a simple real-time
inspection survey, however, it is superior 1n that 1t specifies data
collection consistent with a model that can be used to estimate emissions from
a variety of area sources.
4.2.2 Mass Balance (Screening Technology)
Mass balance technology can be used to Indirectly determine emission
rates by accounting for material in and out of a system and assuming the
difference is lost as air emissions (31). The use of mass balance for
baseline emission estimates at uncontrolled landfill or lagoon sites was not
identified, but it might be applicable to waste lagoons that have minimal
leaching losses. To apply the technology at an uncontrolled site, the
concentration of the species contained in the lagoon (or landfill) would £e
measured Infrequently over time, and the emission rate would be estimated as
the loss of species over time.
Applicability--
The technology would be best suited for homogenous sources containing
highly volatile wastes. Application of the technology to "fresh waste", when
emission rates are typically highest, 1s more feasible than application to
"weathered" waste. The technology does not appear applicable to particulate
matter emission assessment.
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Limitatlons--
The technology 1s generally unsulted to uncontrolled waste sites because
of the source types and since losses of material are difficult to Identify due
to the precision of the sampling and analytical methods. In addition, the
mass balance technology does not distinguish between material lost to other
pathways.
4.2.3 Real-Time Instrument Survey (Screening Technology)
Real-time Instrument surveys are a preferred screening technology for
determining the volatile emissions potential for hazardous waste sites. The
survey consists of Inspecting the site with real-time instruments to determine
the average species concentration in the air layer directly above the site,
and to Identify "hot spots" with above average emission concentration.
Real-time instrument surveys can also include taking headspace concentration
measurements in cracks and vents. They can be used for both volatile species
and particulate matter, but.it is typically used for volatile species
emission.
The site 1s inspected by placing the inlet of the real-time instrument at
a specified height above the surface, typically 2-3 inches to several feet
above the site surface. The site 1s walked on a 25-foot grid as shown in
Figure 18, although the grid may be adjusted to accommodate site size. Upwind
measurements are made before and after Inspecting the site by measuring the
ambient air at 5-feet above the site at an upwind location. Sampling should
be performed during quiescent wind conditions (i.e., average wind speed less
than 5 miles per hour).
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100'
500'
Figure 18. Real-time Instrument survey.
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Appl 1 cabin ty-
The real-time Instrument survey is applicable to all types of hazardous
waste sites, assuming sampling personnel can reach all areas of the site.
Limitations--
The technology does not provide for calculation of an emission rate, but
rather determines the site's potential for air emissions including particulate
matter emissions can be measured using aerosol/dust counting devices.
4.2.4 Concentration-Profile fln-Deoth Technology)
The concentration-profile (C-P) technology measures the concentration of
the emitted species at logarithmically spaced heights at a downwind location
on the anticipated plume centerline (21,34). This technology has been tested
under a variety of waste site conditions and has been shown to produce valid
results. Figure 19 illustrates the C-P sampling approach.
The C-P technology was developed by L.J. Thibodeaux and co-workers at the
University of Arkansas under an EPA contract. The technology is based on
measurements of wind velocity, volatile species concentration, and temperature
profiles in the boundary layer above the waste body. These measurements are
used to estimate the vertical flux of the volatile species as (31):
E
H20
(Eq. 14)
where E1 » emission rate (flux) of organic species i (g/cm2-sec);
D, - molecular diffusivity of organic species i in air
(cm2/sec);
H20 molecular diffusivity of water vapor in air (cm2/sec);
n - exponent for diffusivity ratio;
Sv - logarithmic slope of the air velocity profile (cm/sec);
S, logarithmic slope of the concentration-profile for
organic species i (g/cm3);
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157"
SENSOR
ARMS
89'
52"
WIND DIRECTION
SENSOR
SAMPLINQ
MAST
T- =U \
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MAST SIDE
PANEL
POND
SURFACE
COMPUTER
DATA SYSTEM
Figure 19. Hast sample collection system for C-P sampling.
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K - von (Carman's constant;
tfm - Businger wind shear parameter; and
Sc - turbulent Schmidt number.
The term (^S,.)"1 represents an atmospheric stability correction factor
and 1s expressed as a function of the Richardson number. The function is an
empirical correlation which corrects the estimated emission rate for water
vapor to measured values under various atmospheric stabilities. For this
reason, the correction factor 1s valid only under specific meteorological
conditions.
The sampling equipment consists of a 4-meter mast with a wind direction
indicator, wind speed sensors, temperature sensors, and air collection probes
at six logarithmically spaced heights above the area source; a continuous
real-time data collection system; and a thermocouple for measuring water
temperature. Prior to sample collection, meteorological conditions must be
monitored to determine if sampling conditions meet the necessary
-meteorological criteria. Once acceptable meteorological conditions are
documented, the sample collection period 1s Initiated. During the sample
collection period, wind speed, air temperature, and relative humidity are
measured.
Applicability--
The C-P technology is applicable to emission rate measurement from many
types of large area sources including landfills, lagoons, and areas of
contaminated soils. The technology is applicable for both volatile and
particulate emission rate measurement. It is applicable both for undisturbed
and disturbed site conditions, and for testing emission control technologies.
Limitations--
The technology requires that meteorological conditions during sampling,
particularly wind speed and direction, match the predetermined conditions used
to select the sampling location. The sampling location must be on the
approximate plume centerline.
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The technology also assumes that the site 1s fairly homogeneous;
therefore, the technology may not be applicable to heterogeneous sites. The
technology 1s not applicable to sites where there 1s Insufficient distance
downwind to set up the sampling equipment. The technology also may not
adequately collect emissions from point sources within an area source, such as
cracks 1n landfill covers or vents.
The technology requires upwind sampling to account for other potential
sources. Finally, the technology 1s not applicable during quiescent or
unstable wind conditions, and may produce false negative results during these
conditions.
4.2.5 Transect (In-Deoth Technology^
The transect technology, also referred to as plume mapping, measures the
concentration of the emitted species at several downwind locations aligned
perpendicular to the anticipated plume centerline (21,35). The in-depth
transect technology is an Indirect emission measurement approach that has been
used to measure fugitive particulate and gaseous emissions from area and line
sources. This technology has been successfully tested at a variety of waste
sites, including landfills. Figure 20 illustrates the transect sampling
array.
The transect technology uses horizontal and vertical arrays of samplers
to measure concentrations of species within the effective cross-section of the
emission plume. The volatile species emission flux is then obtained by
spatial integration of the measured concentrations over the assumed plume
area. For volatile species, the emission flux is calculated as (21):
E, - _U_ / / C<(h,w) dhdw (Eq. 15)
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E
re
V)
0)
cr
o
o>
(J
o>
VI
c
re
-------
where *E, emission flux of component 1 (ug/m2-sec);
u wind speed (m/sec);
A, surface area of emitting source (m2);
Ap - effective cross-sectional area of the plume (m2);
C, - concentration of component 1 at point (h,w), corrected for
upwind background (ug/m3);
h * vertical distance coordinate (m); and
w - horizontal distance coordinate (m).
For particulates, the emission flux Is calculated as (36):
mfh.wl dh dw (Eq. 16)
where E - emission flux (ug/m2-sec);
t * sampling time (sec);
As - surface area of emitting source (m2);
Ap - effective cross-sectional area of plume (m2);
m « mass of particulates collected after correction for back-
ground concentration (ug);
h « vertical distance coordinate (m);
w * horizontal distance coordinate (m); and
a « intake area of sampler (m2).
The cross-sectional area of the source (As) term can be eliminated from
both equations, if only the total site emission per time is required. An
alternative equation for volatile species, based on diffusion theory and
measurements, is (33):
n
E.R., - 2 * X,^ oyoz C U (Eq. 17)
where E.R., * emission rate of species i (gm/sec);
Xt - peak concentration of species 1 (Gaussian Fit Curve);
K, « conversion factor gm/ppm for species 1;
ay - lateral extent of Gaussian plume;
97
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oz vertical extent of Gaussian plume;
C - Instrument reponse factor;
* - 3.141; and
0 - mean wind speed.
All parameters are obtained from field measurements. (In some Instances, az
1s estimated from ay).
The sampling equipment consists of a central 3.5-meter mast supporting
three equally spaced air sampling probes, and single wind direction, wind
speed, and temperature sensors at the top; and five 1.5 meter masts with
single air sampling probes. The central mast Is aligned downwind along the
»
expected plume center-line. Two masts are placed on each side of the central
mast perpendicular to the plume center-line at equal spaclngs; and one mast is
used to collect air samples at an upwind location. The spacing of the
associated masts 1s selected to cover the expected horizontal plume
-cross-section, as defined by observation and/or profiling with real-time
^analyzers. Additional sampling locations, both vertically and horizontally,
'can be added as required to provide sufficient coverage of the plume
cross-section. Prior to sample collection, meteorological parameters must be
monitored to determine if sampling conditions meet the predetermined
meteorological criteria.
The transect technology is somewhat less susceptible to changing
meteorological conditions than the concentration profile technology, but it
does not account for the vertical dispersion of the emitted species due to
their varying molecular weights. A more complex array of samplers can be
-employed to overcome this shortcoming, if necessary. The transect Is often
the preferred technology because the technology 1s applicable to a variety of
some types and the resulting data can be more useful since the data are
collected across the plume area.
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Applicability&
The transect technology 1s applicable to emission rate measurement
from all forms of area sources, Including lagoons, landfills, open dumps, and
waste piles.
The technology can be used for both volatile and participate matter
emission rate assessment. The technology 1s applicable both for undisturbed
and disturbed site conditions, and for testing of emission control
technologies. The technology 1s applicable to emissions measurement during
all phases of the RI/FS process and can, therefore, provide directly
comparable data throughout the process, Including post remediation monitoring.
While the method assumes a relatively homogeneous site and a well mixed
plume, these conditions are not necessarily required to use the method. The
placement of sufficient sampling stations across the plume can allow the
technology to be used at a heterogeneous site, or where the distance downwind
for equipment set up 1s limited. However, data collected under these
conditions should be carefully evaluated before use. 4
Limltatlons--
The technology requires that meteorological conditions during sampling,
particularly wind speed and direction, match the predetermined conditions used
to select the sampling locations. The center mast should be on the
approximate plume center!ine. The technology may not adequately collect
emissions from point sources within an area source, such as cracks 1n landfill
covers or vents, unless the plume 1s fairly well mixed at the sampling
locations. The technology provides only limited vertical profiling of the
plume. The technology 1s not applicable during quiescent or unstable wind
conditions; 1t may produce false negative results during these conditions.
Preferred Techno!ogy--
The transect technology 1s a preferred Indirect emission assessment
technology. The technology has been used for several different types of area
sources and Is documented 1n the literature. The applicability of the
technique, the conditions required for sampling, and the moderate level of
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equipment and man-power needs suggest this technology as a preferred
technology relative to other Indirect approaches.
4.2.6 Boundary Laver Emission Monitoring
Boundary layer emission monitoring can be used to determine the emission
rate of pollutants from large heterogenous area sources (37). The technique
1s similar to the transect technique 1n that samples are collected along an
array that 1s perpendicular to the emission plume. However, rather than fixed
sampling locations, the boundary layer technique Involves a cart with three or
more samplers traversing the plume with each sampler at a different height.
During the plume traversing the sampling rate 1s adjusted to be proportional
to the sine of the angle between the wind vector and the direction of the
traverse path. Each run takes about an hour. The average concentrations are
adjusted for any upwind concentration and then used to calculate an average
vertical concentration profile. This profile 1s numerically Integrated (with
the' wind velocity profile) over the contaminant boundary layer to derive an
emission rate for the source.
The emission rate is (37):
[E - C0 WV0 x 10 -6jyo (z/10)"(l-z/Zb)b dz (Eq. 18)
where E « emission rate (g/sec);
C0 » ground level concentration (ug/m3);
W » cross-wind distance (m);
V0 - average wind speed at 10m (m/sec);
Zb « boundary layer thickness (m);
p exponent of wind-velocity profile; and
b exponent of concentration profile.
Applications--
The technique can be used for measuring an emission rate from any type of
source with constant emissions.
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Limitations--
The method assumes that both the contaminant emission rate and the wind
speed and direction are reasonably steady while sampling 1s conducted. The
major sources of error are 1n the average measured wind velocity and 1n
accounting for upwind contamination. The method should be limited to area
sources that do not have significant plume buoyancy, to periods of 1-10 m/sec
winds, and to sampling heights less than the depth of the mixing layer. The
technique has not been validated by the EPA.
4.3 AIR MONITORING TECHNOLOGIES
A1r monitoring technologies that measure the ambient air concentration
resulting from area emission sources are combined with air dispersion modeling
to calculate the area source emission rate. The primary difference between
Indirect emission measurement technologies and air monitoring technologies 1s
the distance at which measurements are made downwind from the source.
In-direct measurements are made near the source or units of a combined site
(usually on site) and may be able to distinguish between multiple units within
a site, depending on the spacing between units. Air monitoring 1s generally
performed at considerable distance downwind from the source and usually cannot
distinguish between multiple units within a combined site. Air monitoring
typically measures lower concentrations because the contaminant plume is
subject to additional air dispersion.
The first step to use the ambient air sampling data to develop emission
rate estimates 1s to select an air dispersion model which accurately reflects
the site-specific conditions, Including regional and local terrain, typical
wind stability, etc. Guidance for selecting an appropriate model is given in
the EPA's Guideline on Air Quality Models (38). Preferred models given in the
guidance document Include the Cllmatologlcal Dispersion Model (COM 2.0),
Gaussian Plume Multiple Source Air Quality Algorithm (RAM), Industrial Source
Complex Model (ICS), and Single Source (CRSTER) Model. A number of other
potentially applicable models are Included In the guidance document. Models
not Included 1n EPA's manual also may be applicable at uncontrolled hazardous
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waste sites, Including the Point Plume Model (PTPLU), and the Gifford and
Hanna Simple Box Model (39). The models are used with air monitoring and
meteorological monitoring data to estimate emission rates.
A1r monitoring and air dispersion models are used to determine the
emission rate through an Iterative process. An emission rate Is first
estimated for the area source. This estimated emission rate, along with
meteorological data collected during air monitoring, 1s used to calculate a
predicted downwind concentration. The predicted concentration 1s then
compared to the measured downwind concentration. Based on this comparison,
the estimated emission rate 1s adjusted appropriately, and the process 1s
repeated until acceptable agreement 1s reached between the measured and
predicted downwind air concentrations.
The air monitoring technologies that can be used to develop BEEs are
listed below. These technologies were described In Section 4.2 and can be
- used at greater distances downwind of the emission source as air monitoring
technologies.
Screening Technologies--
4.2.1 Upwind/Downwind
In-Depth Techno!ogles--
4.2.4 Concentration-Profile
4.2.5 Transect
4.2.6 Boundary Layer Emission Monitoring
4.4 EMISSIONS (PREDICTIVE) MODELING
Emissions models have been developed to predict emission rates for a
variety of waste site types Including landfills without Internal gas
generation, landfills with Internal gas generation (typically co-disposal
sites), open dumps, waste piles, spills, land treatment operations, aerated
>-i , t.
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lagoons, non-aerated lagoons, and lagoons with an oil film. These models are
almost exclusively theoretical, and each model Is generally applicable to only
one type of waste site.
The predictive models can be used as screening or 1n-depth technologies.
Emissions models, used as screening technologies, use data that can be
obtained or calculated from Information available 1n the literature, or can be
assumed with some level of confidence. Emissions models, used as 1n-depth
technologies, require site-specific site and waste characterization data. The
selection of model Input sources (site-specific, literature value, or assumed)
should be based on the requirements of the decision-making process and the
level of resources available. Site-specific data should be used whenever
*
possible to Increase the accuracy of emission rate estimates.
Several predictive models are presented below to acquaint the reader with
the types of available models for emission rate estimation. The models
presented do not Include all available models. Specific methods for
calculating the model Input variables, such as diffusion coefficients, have
been presented by the authors of the models, but are not Included here for
sake of brevity. Each model requires estimating the emission rate of the
Individual components of the waste; and then summing the emission rates to
determine the overall emission rate. For complex waste, application of the
models 1s best performed on a computer to speed the calculation. An emission
flux can be calculated by dividing the emission rate by the emitting area.
A wide variety of variables are associated with each of the predictive
models; however, a number of key Inputs are required by many of the models.
These key Inputs for landfills Include: the vapor diffusion coefficient
through the soil or mass transfer coefficient across the air/soil boundary for
waste constituents; the physical size of the source expressed as area, length,
and/or width, depending on the model used; physical parameters of the landfill
cover, such as depth of cover, permeability, and soil porosity (total,
air-filled, and/or effective porosity); physical/chemical parameters of the
waste, Including chemical composition, weight or mole fraction for
constituents, vapor concentration of constituents at the waste surface or
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within the soil cover, and partial pressures of constituents; atmospheric
conditions, such as temperature, wind speed and direction, and barometric
pressure; and estimates of the soil gas velocity through the soil cover. The
key Inputs for lagoons include: mass transfer coefficients; physical/chemical
parameters of the waste, Including chemical composition, weight or mole
fractions, partial pressures, and Henry's Law Constants; physical dimensions
of the lagoon surface; atmospheric conditions, such as temperature, and wind
speed and direction; layering of waste within the lagoon; and physical/
chemical parameters of a surface crust.
While all of these parameters can be estimated with varying levels of
confidence, it 1s best, when possible, to collect site-specific data.
Physical/chemical measurements of waste constituents can be obtained from
sampling and analysis programs, although a records review is advisable to
identify key constituents and ensure representative sampling. Likewise a
sampling and analysis program combined with a records search 1s desirable to
determine the physical size and shape of the source and the porosity and
permeability of any soil cover. Atmospheric conditions are easily obtained
from various weather services which can provide regional data; however,
collecting some site-specific meteorologic data to ensure representativeness
is desirable. Diffusion and mass transfer coefficients are typically
calculated based on the wastes' chemical composition and their known chemical
properties, such as Henry's Law Constants, although tabulated diffusion
coefficients are now available. The referenced literature includes suggested
methods for calculating the diffusion coefficients as well as some tabulated
data. Diffusion and mass transfer coefficients can also be determined
experimentally In the lab; however, disturbance of the waste and landfill
cover to obtain site-specific materials would probably introduce uncertainty.
The landfill models presented here can be categorized into five types:
Closed landfills without Internal gas generation--Farmer Model, Shen
Model, Thibodeaux a Model, Logarithm Gradient Model, and RTI Closed
Landfill Model;
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Closed landfills with Internal gas generation--(Thibodeaux)
Convective "Add On" Model, Thibodeaux b Model, and (Thibodeaux)
Exact Model;
Open landfills--Arnold's Open Landfill Model, Shen Open Landfill
Model, and RTI Open Landfill Model;
Landfarming--RTI Landtreatment Model and Thibo-deaux-Hwang Model;
and
Fugitive dust -- AP-42.
The lagoon models presented here can be categorized into two types:
Non-aerated lagoons -- Mackay-Lienonen; Thibodeaux, Parker, and
Heck; Smith, Bomberger, and Haynes; Shen; and RTI.
Aerated lagoons -- Thibodeaux, Parker, and Heck; and RTI. ^B
The bases for most of the landfill models are Pick's First Law of
steady-state diffusion, Pick's Second Law of unsteady-state diffusion, the
Equation of Continuity, and Darcy's Law.
4.4.1 Emission Models for Closed Landfills without Internal Gas Generation
Parmer Model--
The Parmer Model (40-43) was one of the first models developed and
generally accepted to predict emission rates from covered landfills. The rate
at which a compound is lost to the atmosphere from the land surface is
controlled by the compound's molecular diffusion through the soil covering the
waste. Fanner et al. developed this model to determine hexachlorobenzene
vapor diffusion through a soil cover. They found that the two prime factors
controlling/determining vapor movement through the soil were soil depth and
soil air-filled porosity. The model should be applicable to other compounds
as wel1.
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i
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The Farmer Model combined Pick's First Laws for steady-state diffusion
with the Milling ton and Quirk evaluation of the diffusion coefficient. The
latter Included a porosity term accounting for the soil's geometric effects on
diffusion for a given compound.
The Farmer equation Is (41):
J - D1(CrC2)(P.10/3/PT2)A (Eq. 19)
where J volatilization vapor flux through the soil cover
(ug/cmz-day);
D, - vapor diffusion coefficient In air (cnrYday}-;
Pa - air-filled soil porosity (cm3/cm3);
PT « total soil porosity (cm3/cm3);
C2 » concentration of volatilizing material at the surface of
soil layer (ug/cm3);
C, - concentration of the volatilizing material at the bottom
of the soil layer (ug/cm3); and
L depth of the soil layer (cm).
Farmer et al. simplified the equation somewhat by assuming a worst-case
scenario, where the soil 1s completely dry (Pa equals PT) and where the
concentration at the surface (C2) equals 0, meaning any Increase 1n C2 would
effectively reduce the driving force behind the vapor flux and, thus, reduce
the vapor flux from the soil surface. Fanner et al. called this equation the
Assessment Application (41):
J - D,PT4/3Cs/L (Eq. 20)
Appl 1 cablll ty
The Fanner Model provides an estimate of Individual compound emissions.
The Intended applicability of the Fanner Model 1s quantification of
steady-state volatile chemical fluxes from hazardous waste landfills. This
model does not account for convectlve transport due to biogas generation and
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1s not applicable to municipal landfills or other landfills containing gas
generating wastes. Use of the Fanner Model assumes the transport of a
volatile compound through the soil cover layer Is controlled by a molecular
diffusion process.
L1m1tat1ons--
The Fanner Model assumes that the soil/waste below the soil cover layer
1s saturated with constituent 1. This assumption tends to overestimate the
emissions by not accounting for the true concentration gradient below the soil
cover. Additionally, the Fanner Model does not account for the emissions
associated with atmospheric/meteorological effects such as barometric pressure
fluctuations. Also, at high concentrations (greater than 5 percent by
volume), the diffusion process creates Its own convectlve sweep or apparent
velocity within the landfill. This convectlve mechanism Is not accounted for
by the Farmer Model (44). These latter two limitations are likely to result
1n underestimates of landfill emission rates.
Shen Model--
Shen modified the Farmer Model (45,46,47) to determine a vapor emission
rate, as opposed to the vapor flux rate, and to enable calculation of the
volatilization of specific components of the complete waste mixture. This
modification assumes Raoult's Law applies. Sh»n multiplied the Farmer
equation by the exposed contaminated surface area and by the weight fraction
of the component in the mixture. The modified equation 1s (45):
E, - D^AfP/'3) Uf, (Eq. 21)
where E, emission rate of the component 1 (g/sec);
0, - diffusion coefficient of component 1n air (cm2/sec);
C, saturation vapor concentration of component 1 (ug/cm3);
A - exposed area (cm2);
Pt - total soil porosity (dimensionless);
L effective depth of the soil cover (cm); and
W/W « weight faction of component 1 in the waste (g/g).
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The model assumes completely dry soil and zero concentration of
volatilizing material at the soil surface, a worst-case scenario considered
appropriate for cap design and most analyses for volatilization release from
landfill wastes. This assumption should be used 1n all cases except where
cover soils can be shown to have significant soil moisture. In these
Instances, the soil air-filled porosity should be substituted Into the
equation for the total porosity by replacing Pt4/3 with Pa10/3/PT2-
Appl 1 cabin ty«
The Shen Model differs from the Farmer Model In that 1t relates emissions
to the waste composition with a weight factor (w1) and multiplication of the
flux by the landfill area. Like the Fanner Model, the Intended applicability
is quantification of steady-state volatile chemical emission rates from
hazardous waste landfills. This model does not account for convective
transport due to biogas generation and is not applicable to municipal
landfills or other landfills containing gas generating wastes. In the use of
the Shen Model, it Is assumed that the relatively toxic properties of organic
waste placed In hazardous and Industrial waste landfills minimize gas
production due to blodegradation.
Limitations--
The Shen Model does not account for the landfill gas losses in leachate
systems, run off, or soils. But here again, due to the Inert properties of
the volatile constituents, this accountability Is considered by Dr. Shen to be
minute. The Shen Model also assumes that the soil Is completely dry with no
Internal gas generation. However, the Shen Model can be modified to account
for biogas generation with a multiplicative factor of 6. This assumption
would tend to overestimate emissions by not accounting for actual wet soil
conditions below the soil cover layer. As with the Farmer Model, the Shen
Model does not account for emissions due to meteorological fluctuations (e.g.,
barometric pressure pumping).
Another limitation of the Shen Model 1s the Incorporation of Raoult's Law
to relate the waste composition to emission rate. Raoult's Law Is applicable
only to waste saturated with constituent 1 and Ideal solutions. Application
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of the Shen Model to wastes containing dilute concentrations of the
constituent 1 Is likely to result In an overestimate of emission rate.
Thlbodeaux a Model-
The Thlbodeaux a Model (43,48) was developed by Thlbodeaux to estimate
the emissions of volatile constituents due to Interphase vapor transport from
landfills with no Internal gas generation. The model Is derived from Pick's
Law of steady state diffusion. Molecular diffusion Is the controlling and
only transport mechanism addressed by the Thlbodeaux a Model for the movement
of volatile constituents toward the soil/air Interface and then to the
overlying air. To describe this mechanism, the two-resistance theory 1s used
to describe the two-film resistance 1n which the movement of chemical
constituents 1s limited by their ability to diffuse through the soil and after
migration from the surface, through the air.
The model assumes that a pure component 1 exerts Its pure component vapor
pressure under the earth, subject to normal geophysical and meteorological
factors. Thlbodeaux defines an overall mass transfer coefficient to describe
vapor movement which 1s hindered by both the resistance due to soil
characteristics and diffusion resistances at the air Interface.
E, - % (0,-C,,) A (Eq. 22}
Ei ' E.oii + Eair/soii (E<1- 23)
where 1K, - overall soil phase mass-transfer coefficient (cm/sec);
Cn - concentration of 1 above the soil/air Interface (g/cm3);
C, « concentration of 1 In the sand-filled chamber pore spaces
(9/cm3);
E1 - rate of vapor movement within the soil phase (g/sec); and
A landfill surface area (cm2).
LSOll
«VC,)A (Eq. 24)
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where \ - effective dlffusivity of constituent 1 within the pore
spaces (cm/sec);
L - depth of the soil fill cover (cm); and
C, - concentration of 1 at the air/soil Interface (g/cm3).
t (C,-CU) A
(Eq. 25)
where 3D, gas phase mass-transfer coefficient using the equation
developed by MacKay and Natsugu (m/hr).
3D, - 0.0292 Vx°'78 Lx-°'n Sc-°'67
(Eq. 26)
where
- wind speed measured at 10 m (m/hr);
length of the ground emission source in the direction of
the wind (m); and
Schmidt number for the gas.
Overall mass-transfer coefficient:
(Eq. 27)
where
tortuosity, taken to be 3
porosity of the cover material
Applicability--
Llke the Fanner and Shen models, the Intended application of the
Thibodeaux a Model 1s a hazardous waste landfill. This model does not account
for convective transport due to internal gas generation typically present in
municipal landfills.
Umitatlons--
The Thibodeaux a Model does not account for the possible emissions due to
barometric pressure fluctuations or Internal gas generation. In addition, the
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Thlbodeaux a Model does not account for the convectlve sweep of a volatile
constituent caused by high concentrations greater than 5 percent by volume. A
number of factors, such as waste composition, mult1component systems, and
biological or chemical reactions, greatly Increase the uncertainty in the use
of the two-resistance theory.
Logarithm Gradient Model--
The Logarithm Gradient Model (43) 1s the modern day Interpretation of the
Fanner Model developed to address volatile constituent emission rates for
landfill concentrations greater than 5 percent by volume. In general, this
model takes Into account both the diffusive mechanism as described by Pick's
Law and the convectlve mechanism due to the sweep or apparent velocity which
diffusion can create with high concentrations.
The Logarithm Gradient Model is (43):
Ln pM A (Eq. 28)
where E, - emission rate (g/sec);
DE - effective diffusion coefficient (cm2/sec);
PT total pressure below the cover layer (mm Hg);
M - mole weight of constituent (g/mol);
R - molar gas constant (cm3 mm Hg/mol °K);
T - absolute temperature (°K);
L - length of soil cover (cm);
P, partial pressure at the air-soil surface (mm Hg);
P,* * partial pressure of the volatilizing material in soil gas
at the bottom of the soil depth (mm Hg); and
A landfill surface area (cm2).
Appl 1 cabili ty-
This model can generally be applied to landfill situations where
molecular diffusion 1s the controlling vapor transport mechanism. The model
accounts for the apparent velocities associated with high volatile
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concentrations, but does not account for the convectlve sweep movement
associated with co-disposal (biogenic gas production) practices.
Limitations--
The limitations Indicated for both the Fanner Model and the Shen model
apply to this model. However, the Logarithm Gradient Model accounts for
convectlve transport resulting from the diffusion of highly volatile
constituents (greater than 5 percent by volume).
RTI Closed Landfill Model-
The Research Triangle Institute (RTI) closed landfill model (43,47)
accounts for emissions via two mechanisms: diffusion through the soil cap and
convectlve loss from barometric pumping through passive landfill vents. The
model Is based on the Fanner Model (above) which was modified to account for
convectlve losses due to barometric pumping and the decline in emission rate
over time.
The total Instantaneous emission rate 1s a function of the total Initial
emission rate at the time of landfill closure which 1s the sum of the
instantaneous emissions associated with diffusion through the cap and
barometric pumping.
*
E, - £ + E21 (Eq. 29)
*
where E1 total Initial emission rate at the time of closure
(9/sec);
En * emissions associated with diffusion through the cap
(g/sec); and
E21 * emissions associated with barometric pumping (g/sec).
The equations for estimating En and E21 are present below.
30)
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where
where
where
A landfill surface area (cm2);
D, - vapor diffusion coefficient In air (cro2/sec);
PA « soil cap a1r-f1lled porosity (cm3/cm3);
PT total porosity of the soil cap (cm3/cm3);
C, concentration of constituent In the vapor space beneath
the cap (g/cra3);
C, concentration of constituent In the air above the cap
(g/cm3) assumed to be 0; and
L - cap thickness (cm).
Q Ct A
(Eq. 31)
flow rate of gas through the vent (cm3/cm2-sec);
concentration of constituent 1n the gas within the
landfill (g/cm3); and
landfill surface area (cm2).
-[hAEfw
-1
(At A)
(Eq. 32)
(cm);
h - thickness of waste bed within landfill
Efw air porosity fraction of fixed wastes;
Pr - reference barometric pressure (mm Hg);
P1 « final barometric pressure (mm ug);
Tr reference landfill temperature (°C);
Tj final landfill temperature (°C); and
At - time Interval over which change in pressure and/or
temperature occurred (sec).
The total Instantaneous emission rate at any time 1s then computed via an
exponential decay function:
*
E,(t) - 31.56 E< exp(-Xt) (Eq. 33)
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where E,(t)- total time-dependent emission rate (mg/yr);
E, - Initial emission rate, at time of landfill closure
(g/sec);
t - time since landfill closure (mo); and
A decay constant (mo"1) « 2.63 x 106 E,*/^; and
N01 total mass of the constituent 1n the landfill (g).
The average emission rate from a closed, vented landfill over the time since
landfill closure 1s given by the following expression:
EAi(t) - t^ 1 [1-exp (-Xt)] (Eq. 34)
where EA1(t) - average emission rate over the time since landfill
closure (mg/yr);
t - time since landfill closure (mo);
\ - decay constant (mo"1); and
*
E, - Initial emission rate at time of landfill closure
(g/sec).
The RTI closed landfill model assumes that no blodegradatlon occurs and
that the landfill 1s passively vented to the atmosphere. Transport of the
constituent in moving water 1s assumed not to occur.
Applicability--
The RTI Model estimates the time-dependent behavior of emissions from
landfills. RTI modified the Farmer Model to account for the convective loses
from barometric pumping through vents. In addition, the RTI Model was
designed to account for the decline in the emission rate from closed landfills
over an extended period of time. The time dependency was Incorporated simply
by adding an exponential decay function. The decay constant was taken as the
ratio of the emission rate at the time of landfill closure to the total mass
of the constituent in the landfill.
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L1m1tat1ons--
The RTI Model does not Include convectlve or purging action associated
with blogas production commonly found at municipal solid waste landfills. It
assumes, as did the Shen and Fanner models, that the toxic properties of the
waste will Inhibit biological processes and, thus, prevent blogas generation.
Furthermore, the liquid waste which contains the volatile constituent 1 1s
assumed to be bound 1n the fixed waste within the landfill cell. No
experimental or field verification has taken place.
4.4.2 Emission Models for Closed Landfills with Internal Gas Generation
(Thlbodeaux) Convective "Add On" Model-
The Convective "Add On" Model was developed by Thlbodeaux to account for
both the diffusion and convectlve mechanisms present 1n landfills at which
co-disposal of municipal solid waste and hazardous organic waste has been
practiced. The model describes the migration of a chemical constituent 1 due
to the convectlve gas sweep of biological gas production within the soil cover
layer. As the apparent velocity, Vy, of the constituent, approaches zero, the
model reduces to the diffusion controlled Farmer Model described above.
The Convectlve "Add On" Model 1s (43):
Vv (CrC )
E1 ' [expVv)-13 + V yc 1 A <* 35>
where E{ - rate of vapor movement within the soil phase (g/sec);
Vy - mean gas velocity in pore spaces (cm/sec);
C1 - concentration of 1 in sand chamber filled pore spaces
(9/cm3);
C, concentration of 1 at the air-soil Interface (g/cm3);
L depth of fill cover (cm);
DE effective dlffusivlty of 1 within the soil pore space
(cmz/sec); and
A - landfill surface area (cm2).
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Appl1cabillty--
The Convectlve "Add On" Model can be used to estimate volatile emissions
from landfills with Internal gas generation. This model accounts for both
diffusion and convectlve transfer. However, the transfer due to net upward
gas flow greatly overshadows the diffusion transfer mechanism (44). This
deduction 1s based, In part, on laboratory experiments of simulated gas flow
through a soil cover.
L1m1tat1ons--
A major limitation of this model 1s the required Input of mean gas
velocity through the soil cover. The limitations applied to the Farmer and
Shen Models apply to this model as well. However, the "Add On" Model does
account for biogas convection.
Thlbodeaux b Model--
The Thlbodeaux b Model (43,48) Includes emissions due to barometric
pressure pumping. The model accounts for the air emissions resulting from
concentration gradients (diffusion), biogas generation sweeps (convection),
and barometric pressure pumping (convection) (49). The barometric pressure
fluctuations create a pressure gradient within the landfill cell, pumping
vapors to the atmosphere.
The Thlbodeaux b Model Incorporates Darcy's Law to characterize the
laminar flow of gases flowing through porous media due to pressure gradients.
The gas flow velocity within the landfill cell can be estimated as:
V - (kpg/uL)(P-/>) - (Kg/L)(P-*) (Eq. 36)
where V velocity;
k - specific permeability of covering material in Darcys or
cm2;
u viscosity of gas;
p » density of gas;
L - soil cover thickness;
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P - landfill cell pressure;
* - barometric pressure;
g - acceleration of gravity; and
K permeability (cm/sec).
The Thibodeaux b Model 1s (43):
OF
^ EI - r ci ^^ A (Eq-37)
where R J.V (Eq. 38)
(P-*) (Eq. 39)
E, - emission rate (g/sec);
C, - concentration of 1 1n the sand chamber filled pore spaces
(9/cm3); .
V - superficial velocity through the soil cover layer
(cm/sec);
k « permeability jf soil cover layer material (cm2 cp/sec
atm);
P - landfill cell pressure (atm);
u - landfill cell gas viscosity (cp);
K - atmospheric pressure (atm);
L depth of soil cover layer (cm);
DE - effective dlffuslvlty of 1 within the air-filled soil
pore space (cm2/sec); and
A - landfill surface area (cm2).
Appl 1 cabH1 ty--
The Thibodeaux b Model can be applied to situations where molecular
diffusion, convection, and barometric pressure fluctuations are to be
expected. Efforts by Springer Indicate that the annual barometric pressure
117
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fluctuation does not average out to one and, therefore, should be considered.
Furthermore, Springer observed through computer simulations of flux with
benzene that barometric pressure fluctuation only slightly Influenced the flux
rate at co-disposal facilities, and greatly Influenced the flux rate at
hazardous waste landfills where no Internal gas generation Is expected.
Limitations--
The limitations observed in Thibodeaux's Convectlve "Add On" Model
applied to this model with the exception of barometric pressure fluctuations.
Springer's observations Indicate that the Thibodeaux b Model 1s applicable to
landfills with no internal gas generation (49).
Exact Model--
The Exact Model, (43) developed by Thibodeaux, Is a steady state model
which accounts for diffusion due to concentration gradients, the convective
velocity created by highly volatile compounds, and convection due to biogas
generation (50). Application of the model requires an iterative procedure,
since the flux term, J1, appears on both sides of the equation. The Logarithm
Gradient Model discussed above Is used to calculate the initial estimation of
the flux to start the Iterative calculation. Since It 1s a steady-state
model, the flux 1s not given as a function of time and the concentration of
constituent 1 is assumed to be constant within the landfill cell.
The Exact Model 1s (43):
VP.M.
A A
RT
1 -
+ C LVPTD,
(Eq. 40)
where
V -
MA"
PT-
1 -
D -
volatile chemical flux (g/cmz-sec);
apparent biogas velocity (cm3/cm2-sec);
vapor pressure of chemical A (atm);
molecular weight of chemical A (g/mole);
atmospheric pressure (atm);
soil Jayer thickness (cm);
effective diffusion coefficient (cm2/sec);
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^..,-Al .. ,,
:< EN - enhancement factor from experimental data;
DA1 diffusion coefficient of chemical A In air;
e porosity of soil layer;
e, « air-filled porosity of soil layer;
R - molar gas constant; and
T absolute temperature (*K).
Applicability
The Intended applicability of this model 1s municipal landfills with
Internal gas generation. This model can be used to estimate the flux of a
volatile constituent 1 from closed landfills due to both diffusion and
convective transport mechanisms. However, this model can only be used for
landfills with an internal gas velocity greater than zero.
Limitations--
When the model predictions were compared to the experimental data s
developed by Thlbodeaux, large discrepancies were observed. The experimental
emission rates were higher than the model predictions, and Thlbodeaux
attributes this deviation to surface diffusion which occurs in parallel with
pore diffusion and, in general, enhances the total diffusion rate.
Thlbodeaux Incorporates the enhancement factor, EN, in the Exact Model to
account for the discrepancies observed between the effective diffusivity
(obtained by laboratory experiments) and the Millington-Qulrk diffusivity.
Therefore, one major limitation of Thibodeaux's Exact Model 1s the
availability and accuracy of the enhancement factor. Another limitation of
Thibodeaux's Exact Model 1s that the value of the apparent gas velocity, V,
needs to be known. In order to apply Thibodeaux's Exact Model, the
enhancement factor needs to be experimentally obtained for the specific
constituent, soil type, soil cover depth, gas type, gas velocity, and gas
humidity.
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Thibodeaux's Exact Model may be useful 1n estimating the order of
magnitude value of the emission flux If the soil cover depth 1s less than 10
cm. The enhancement factor for a shallow soil cover (I.e., 7.62 cm) ranges
from 1.58 to 4.93 compared to the range of 5.54 to 17.2 for a deep soil cover
layer (I.e., 38.1 cm).
4.4.3 Emission Models for Open Landfills
Arnold's Open Landfill Model--
The Arnold Open Landfill Model (43) provides an estimate of the
cumulative vapor release from the surface of open landfills as a function of
time. Arnold's Open Landfill Model applies Pick's Second Law of unsteady-
state diffusion to describe the diffusion process from a liquid surface at
which the concentration of volatilizing liquid remains constant. The model
assumes that the air space above the liquid surface is at a constant pressure
and convective forces are absent.
In applying Pick's 'Second Law, Arnold incorporated a correction factor
for Pick's Second Law to account for the displacement of the air (or Inert gas
medium) by the volatilizing constituent. This correction factor is a function
of the equilibrium vapor pressure of the constituent. Values of Pick's
correction factor, Pv, are plotted against equivalent vapor pressure in Pigure
21.
The Arnold Open Landfill Model is (43):
(Eq. 41)
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0.2-
20
100
Equilibrium Vapor Pressure, %
Reference: Shen, T.T., "Estimating Hazardous Air Emissions from Disposal Sites." Pollution
Engineering. August, 1981.
Figure 21. Pick's correction factor, Fv, plotted against equivalent
vapor pressure, Ce.
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where V° - volume of vapor released at ambient pressure and
temperature (cm3);
*
y » equilibrium mole fraction of the volatilizing component
1n the gas phase at the liquid-gas Interface;
A - area of the liquid surface (cm);
D1 d1ffus1v1ty of volatilizing component 1n air (cm2/sec);
t - time (sec);
Fv - Pick's Law correction factor; and
* - 3.1416
Applicability--
The Arnold Open Landfill Model Is applicable to open landfills and dumps
where emissions are due to volatilization at the landfill surface.
Limitatlons--
The model assumes that emissions do not occur due to biogas production or
barometric pumping. The model also does not account for the effects of wind
' speed which would tend to increase the emission rate. Finally, the model
assumes a constant waste source, whereas, a surface crust may form as volatile
% constituents are lost from the surface soil. This crust may then act similar
to a landfill cover.
Shen's Open Landfill Model--
Shen's Open Landfill Model (43) provides the average volumetric emission
rate of the volatile constituent from open landfill surfaces. Shen modified
the Arnold Open Landfill Model to account for the convection due to wind
speed. Shen took the time derivative of the Arnold Model and changed the time
function, t, 1n the model to a position function. This position function is
related to the length of the open dump and the wind speed.
The Shen Open Landfill Model is (43):
dV
(Eq. 42
dt ....-_ i
avg
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3
- average emission rate (cm /sec);
vg
where y, - equilibrium mole fraction;
UL width of open landfill (cm);
D, diffusion coefficient (cm2/sec);
U wind speed (cm/sec);
Fv - Pick's law correction factor;
LL - length of open landfill (cm); and
x - 3.1416
The model has also been presented as Ziegler's modification of Arnold
as (45,50):
4Y - 2 CeW (DLv/*FY)1/2Wi (Eq. 43)
dt
where dY -emission rate;
dt
W - width of landfill;
L « longest dimension of the landfill;
v -wind speed;
Hi - weight fraction of a specific compound in the waste;
Ce - equilibrium vapor concentration;
D - diffusion coefficient; and
FY - correction factor.
The emission rate can Increase with increasing wind speed; however, the
dilution fraction also Increases. The net effect of wind speed on ambient
concentration, therefore, becomes compensative and depends on receptor
location.
Appl1cabllity--
The Shen Open Landfill Model 1s applicable to open landfills where
emissions are due to volatilization at the landfill surface. It appears that
this model Is useful as a screening process to examine whether volatilization
will be significant for a given contaminant (46).
123
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Umitatlons--
The model does not provide for biogas generation or barometric pumping.
The model also does not provide for the formation of a weathered surface which
would tend to reduce emissions similar to a closed landfill cover.
RTI Open Landfill Model--
Research Triangle Institute (RTI) modified the Shen Open Landfill Model
by Introducing the mole fraction of the constituent to account for more than
one volatile constituent 1n the liquid. The RTI Open Landfill Model, shown
below, uses the Ideal gas law to convert the volumetric emission of the
Shen Open Landfill Model and provide an average mass emission rate.(40,41)
The RTI Open Landfill Model 1s (43):
2PM.Y,* W,
1_ 3 L
where E, average mass emission rate of component 1 (g/sec);
P * ambient pressure (mm Hg);
M1 - molecular weight of component 1;
*
Y, equilibrium mole fraction of component 1;
WL « width of open landfill;
D, - d1ffus1v1ty of component 1 In air (cm2/sec);
LL - length of open landfill (cm);
U wind speed (cm/sec); and
Fv « Pick's Law correction factor.
Appl 1 cabill ty~
The RTI Open Landfill Model 1s applicable to open landfills where
emissions are due to volatilization at the landfill surface.
Limitations-- The model does not account for biogas production, barometric
pumping, or formation of a surface crust.
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-4.4.4 Emission Models for Landtreatment
RTI Land Treatment Model-
Research Triangle Institute (RTI) has developed a model (42,43) for
estimating emissions from land treatment areas. The model 1s comprised of two
equations; one for short time (Immediately after application or tilling) and
one for longer times. The RTI land treatment equations are based on the
premise that emissions are limited by vapor diffusion through the soil. The
model accounts for the removal of organic material from the land treatment
area by both biological degradation and air emissions.
The expression for the Instantaneous emission rate for short time periods
Immediately following Initial waste deposition 1s given by:
H. L
La Ia__ . I_L_ 1/2 rt/t h (Eq. 45)
where E - emission rate of constituent (g/cm2-sec);
M0 - area loading of constituent (g/cm2);
1 - depth of waste in open landfill (cm);
ea volume fraction of air-filled voids In the soil
(dimensionless);
Kq - ratio of gas-phase constituent to total constituent in
solid waste (dimensionless);
Kg - gas-phase mass transfer coefficient (cm/s);
t time after waste application to the landfill site (sec);
De - effective diffusion coefficient of constituent 1n the
solid waste (cm2/sec); and
tb - time constant for biological decay (I.e., time required
for 63.2% of constituent to be degraded.
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For longer times after application or tilling, when most of the
constituent 1s not present 1n the soil, the short-term equation will over
estimate air emissions. Under these conditions, the following equation 1s
applicable:
E. o ex J e-Vtb (E«. W)
where E - emission rate a long time after application or tilling
(g/cm2-sec); (all other parameters are the same as
presented above).
Applicabillty--
The RTI Land Treatment Model 1s applicable to sites where liquid or
semi-liquid waste 1s applied to the soil surface. The model assumes that
emissions from the surface are limited by diffusion of vapors through the pore
space of the soil/waste mixture. The model accounts for removal of organic
material from the soil/waste mixture by both biological degradation and air
emission.
Limitations--
The model Is not applicable to wastes which are easily biodegraded, or to
sites with highly porous soils which allow easy vertical migration of the
liquid waste. The model does not account for losses to these or other
pathways.
Thibodeaux-Hwang Model--
Thibodeaux and Hwang developed a model for determining volatile emissions
from land treatment operations (49,51,52). The liquid being land-treated is
assumed to soak Into the soil, coating the pore walls. The liquid then
evaporates from the pore walls and diffuses through the soil pores to the
soil/air Interface. After a short period of time, a dry zone develops at the
soil surface, with a wet zone below. Over time, the thickness of the dry zone
Increases while the thickness of the wet zone decreases.
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The rate of emission can be determined by:(51)
where
< [h 2 .2 De, t A (hD-hs)C<0 1/21
L s M -I
(Eq. 47)
Mo
'ig
As f(y
1o
. 48)
A -
A, -
C1g
C10
De1
Dw1 -
H
hs -
M10-
t -
y
Z -
surface area over which waste 1s applied (cm2);
Interfacial area per unit volume of soil for the oily
waste, (cm2/cm3);
effective wet zone pore space concentration of component
1 (9/cm3);
concentration of component 1 in oil (g/cm3);
effective d1ffus1v1ty of component 1 1n the air-filled
soil pore spaces (cm2/s);
effective diffusivity of compound 1 1n the oil (cm2/s);
flux of component 1 from the soil surface (g/cmz-sec);
(hp2 + hph$-2hs2)/6 accounts for the lengthening dry zone;
Henry's Law constant 1n concentration form (cm3 oil/cm3
air);
depth of soil contaminated or wetted with landtreated
waste (cm);
depth of subsurface Injection, if applicable (cm);
Initial mass of component 1 Incorporated Into the zone
(hp-hs), (g);
time after application (sec);
height of wetted soil remaining after partial drying
(cm); and
oil layer diffusion length (cm).
127
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Appl1cab1l1ty--
The Thlbodeaux-Hwang land treatment Model Is applicable to determining
volatile emissions from landfarming of liquid wastes, Including oily wastes.
The model assumes that the soil column 1s Isothermal, liquid movement
does not occur by capillary action, adsorption to soil particles does not
occur, and biochemical oxidation does not occur (49). All of these factors
would tend to reduce the emission rate.
Limitatlons--
The model 1s not applicable to wastes which are easily biodegraded, or to
sites with highly porous soils which allow easy vertical migration of the
liquid waste. The model does not account for losses to these or other
pathways.
4.4.5 Fugitive Dust
Fugitive dust at hazardous waste sites (airborne wastes or contaminated
soils) most commonly results from wind erosion of the wastes or vehicular
travel over unpaved contaminated roads. The U.S. EPA has developed equations
to estimate fugitive dust emissions arising from vehicle travel on unpaved
roads (AP-42). The U.S. Soil Conservation Service (SCS) has developed a model
for predicting fugitive dust emissions resulting from wind erosion.
The SCS model takes Into account such factors as surface soil moisture
content, roughness, and cloddiness, type and amount of vegetative cover,
wind velocity and the amount of soil surface exposed to the eroding wind
force. The SCS equation can be expressed as:
E - f(r,C',K',L',V) (Eq. 49)
.where E potential annual average wind erosion soil loss;
T - soil credibility Index;
C' climatic factor;
K' soil ridge roughness factor;
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L' - field length along the prevailing wind direction; and
V - vegetative cover factor.
The SCS wind equation computes total fugitive dust emissions due to wind
erosion which result from the combination of surface creep, saltation, and
suspension. If only the fraction of soil loss that 1s suspendable and
trans-portable over significant distances by wind Is desired, the wind
equation must be adjusted (reduced) to reflect emissions from only this
phenomenon. The SCS wind erosion equation 1s not reliable when altered to
estimate short-term emissions. The nodel 1s designed to estimate annual
erosion losses only.
The U.S. EPA has developed the following equations which Can be used to
estimate fugitive dust emissions resulting from vehicular travel on
contaminated unpaved roads (53):
EyT.R(5.9,
or 1n metric form:
4
/_s WSj>\/W_\0.7/w\0.5 f?65- (Eq. 51)
U2M48A2.7/ U/ V 365
where E^ - emission factor for vehicular traffic;
k - 0.45 - particle size multiplier for particles <10um
(i.e., particles that may remain suspended once they
become airborne and which can be inhaled Into the
respiratory system);
s - silt content of road surface material;
Sp mean vehicle speed;
W mean vehicle weight;
w mean number of wheels; and
Dp number of days with at least 0.254mm (0.01 Inch) of
; precipitation per year.
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To estimate fugitive emissions due to vehicle travel for a given time
period, the emission factor, EVT defined above, Is multiplied by the vehicle
miles traveled during that time period. Maximum release conditions may be
estimated by using a small value of Dp In the model to reflect assumed
drought conditions. Average emissions can be estimated by using annual
average value for Dp.
Appl 1 cabin ty-
The AP-42 dust model 1s only applicable to dust resulting from vehicular
traffic. The SCS model 1s applicable for wind-blown dust.
Limitations--
The SCS model, as presented, does not provide sufficient detail for
application.
4.4.6 Additional Models
Additional models Identified but not Included here are: Hwang's
modification of Farmer, (51,54) RTI Open Dump Model, (42) Hartley Method,
(36,55) Hamaker Method, (55) and Dow Method (55). The latter three equations
were developed for volatilization of pesticides applied soil.
4.4.7 Non-Aerated Lagoons
Mackay and Leinonen Dynamic Two-Film Model--
This dynamic model (56,57) best serves those Instances Involving Isolated
disposal of a given quantity of waste, as opposed to the steady-state scenario
offered by the other models. Laboratory validation of this model was reported
(57).
This model assumes that nearly stagnant films of well mixed bulk air and
water systems occur on both sides of the liquid/air Interface.
HI - *,i (C, - P/H,) (Eq. 52)
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-------
'where N, - mass flux rate (mol/m2-hr)
K1L overall nass transfer coefficient (m/hr)
C, concentration of 1 (mol/m3)
P, - equilibrium partial pressure of 1 In the vapor (atm)
H, - Henry's Law constant for 1 (atm-m3/mo1)
Appl 1 cabin ty-
The model offers an alternative to the steady-state scenario. However,
Wetherold (36) reports that despite Its theoretical validity, the model 1s
difficult to apply to the "real world." The Input parameters are difficult to
determine or find in available literature. And, this model best applies to
the emissions of single compounds.
Limitations--
The model fails to provide for white caps, thermoclines, eddy diffusion
and other similar phenomena, tending to under-predict emissions when these
conditions occur at the lagoon.
Thibodeaux, Parker and Heck Model--
This model (52), which can be applied to both non-aerated and aerated
lagoons, evolved from basic accepted theories of mass transport. It 1s used
to determine emission rates of individual compounds, assuming that the
concentration of each compound remains constant in the aqueous phase (it does
not interact with the other compounds present). It also assumes that the
influx of the compound 1s steady, that its biodegradation rate is steady, and
that the lagoon surface can be clearly separated Into either quiescent (non-
aerated) or turbulent (aerated) zones.
To use the equation, four mass transfer coefficients must be determined
from Impartial relationships.
q, - M^ (X, - X,*) (Eq. 53) ^
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For each volatile component 1:
t t
k1 HkJ
+ A,,) (Eq. 54)
{Eq' 55)
n
*1 Kl "Kg
where q, - flux of component 1 from the lagoon surface (g/cm2-sec);
M, - molecular weight of component 1 (g/g-mol);
Klt - overall liquid-phase mass transfer coefficient for
component 1 (mol/cm2-s);
X, - mole fraction of component 1 1n the aqueous phase (this
must be measured); and
X,* mole fraction of component 1 1n equilibrium with the mole
fraction of -1 in air, (Y1t where 1f Y, 1s assumed to be
negligible, X,* can equal 0);
Kj , k? - overall liquid-phase mass transfer coefficient for
aerated non-aerated zones of a lagoon, respectively
(mol/cm2-s); and
At, A,, surface areas of aerated and unaerated zones,
respectively (cm);
K j, k j» Individual liquid phase mass transfer coefficients for
the aerated and unaerated zones, respectively (mol/cm-s);
K , K" - Individual gas phase mass transfer coefficients for the
aerated and unaerated zones, respectively (mol/cm-s); and
H - Henry's Law constant In mole fraction form (y » Hx).
132
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Appllcabinty--
The Thtbodeaux, Parker, and Heck model 1s applicable to aerated, non-
aerated, and combined lagoons. The model assumes steady-state conditions and,
therefore, Is applicable to undisturbed lagoons. The model Is probably not
applicable to disturbed (disturbed sludge) conditions.
Limitations
The accuracy of this model has not been verified as of 1982. Wetherold
(36) expressed some skepticism regarding the accuracy or availability of some
parameters necessary for the calculation of the mass transfer coefficients.
Also, the model requires additional development to satisfy the need for a
predictive model capable of predicting total VOC emissions from- a lagoon
containing a complex mixture of compounds (36).
One way to deal with this, as suggested by OeWolf (52), 1s to sum up the
emissions estimated for several classes of compounds by selecting a
representative compound from each class. Acknowledging this selection as
"arbitrary", DeWolf provides some suggestions, noting that some compounds are
more likely to be encountered and those 1n mid-molecular weight range of 4 to
8 carbons are "likely to dominate 1n frequency of occurrence". He suggests:
Class Compound
Paraffins Hexane
Oleflns Butene
Aromatlcs Toluene
Halogenated hydrocarbons Methylene chloride
Oxygenated hydrocarbons Acetone
Smith, Bomberger, and Haynes Model--
The Smith et al. model (36) Is applicable to emissions prediction for
highly volatile compounds in a lagoon setting. The model 1s not applicable to
low and Intermediate volatility compounds. Also, liquid phase resistance
should be the controlling resistance.
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The volatilization rate 1s expressed as a first-order kinetic equation.
(Eq. 58)
env
.where E - mass emission rate per unit volume (Ibs/gal-day);
(K*)env- volatilization rate constant for compound a 1n the environment
(day'1);
*
c - concentration of compound a (Ibs/gal);
Ka ratio of volatilization constants of compounds a and oxygen as
K*
lab K lab measured In laboratory (dimensionless); and
: (K')env » oxygen reaeration rate 1n the environment (day"1).
Applicability
The model is applicable to volatilization of high volatility compounds
from non-aerated waste disposal lagoons.
Li'nitations--
The model is limited in that 1t 1s designed to predict emission rates of
highly volatile Individual compounds and It may be difficult to apply to
complex multicomponent wastes. The model Is not appropriate for estimating
emissions of low or Intermediate volatility compounds. Also, Wetherold (1982)
notes that determining the ratio of volatilization constants of a compound
(Ka/K') is expensive in the laboratory; attempts to estimate this ratio simply
using diffusion coefficient valves Increase the model's overall uncertainty.
Shen Model--
The Shen Model (47,58) presents an empirical equation for determining
volatile emissions from lagoons. The Shen Model 1s (47):
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-------
and,
ERp, - 18 x 10
'6
(Eq. 59)
where ERP1 - emission rate potential of compound 1 (g/sec);
A « lagoon surface area (cm2);
C, - concentration of compound 1 1n lagoon (mg/1); and
KL, liquid-phase mass transfer coefficient of compound i (g
mol/cmz-sec).
'3
'0-5
*-20
- 4.45 x 10' (M,)'- (1.024)*-2 (U)
°'67 '0'85
(H)
(Eq. 60)
where M, - molecular weight of compound 1 (g/mole);
t - lagoon surface temperature (oc);
U - surface velocity 0.035 wind speed (cm/sec); and
H - average liquid depth of the lagoon (meter).
Applicability
The Shen Model 1s applicable as a screening technology to estimate
volatile emission rates from lagoons. It appears, from Shen's discussion,
that the model assumes the lagoon Is a dilute water solution, although this is
not explicitly stated. Shen Indicates that the model should only be used when
"emission rates and risks are clearly acceptable or unacceptable. "(47)
Limitations--
The model should be limited to use as a screening technology.
RTI Model -
The RTI Model 1s a simple volatile constituent mass transfer model (42):
E, - K,A C,
(Eq. 61)
135
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where E1 - air emissions for component 1 from the liquid surface
(g/sec);
K1 - overall mass transfer coefficient for component 1
(m/sec);
A - liquid surface area (m2); and
Ct « concentration of component 1 In the liquid phase (g/m3).
The calculation of the mass transfer coefficient (K{) will depend on
whether the lagoon 1s quiescent, turbulent, a combination of quiescent and
turbulent, or has an oil film. In addition, the equation can be adjusted to
account for losses due to biodegradation. Several methods for calculation of
KL are given In the listed reference as well as examples for applying the
»
model to specific site types.
Applicability--
The RTI Model Is applicable to assessing volatile emissions from aerated
and non-aerated lagoons. The model Is applicable to quiescent and turbulent
lagoons and can be adjusted to Include biodegradation, although the toxic
mature of most waste lagoons will limit biological activity. The model Is
-applicable to both undisturbed and disturbed site conditions.
Limitations--
The model 1s not applicable to lagoons with a surface crust. While the
calculation of the mass transfer coefficient Includes wind speed for quiescent
lagoons, the turbulent lagoon calculations appear to consider wind speed to
have negligible affect on the emission rate.
4.4.8 Aerated Lagoons
Thibodeaux, Parker, and Heck Model--
This model 1s described 1n 4.4.7.
RTI Model-
This model Is described in 4.4.7, and can be adjusted for aeration.
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SECTION 5
CASE STUDIES
Section 5 1s a collection of five case studies that demonstrate the
protocol described 1n this manual for developing BEEs. The purpose of this
section 1s to document different experiences regarding site Investigation and
characterization and to demonstrate the protocol for developing BEEs as
applied to these case studies. The sites selected represent different regions
of the country, different types and distributions of waste, varying levels of
air emissions potential, and varying levels of historical air pathway analyses
(APA) performed 1n support of the Remedial Investigation/Feasibility Study
(RI/FS) process.
Only the first case study demonstrates application of the complete
protocol. The protocol was Implemented only partially at the other sites.
The assessment technologies used (or not used) 1n these case studies do not
necessarily represent the best or most technically suitable assessment
technologies. Many factors Influenced the decision-making process concerning
the development of BEEs leading to air pathway evaluations. Also, the work at
these sites was conducted without the benefit of a formalized protocol for
designing APA programs and developing BEEs.
5.1 CASE STUDY 1: PETROLEUM WASTE LANDFILL/LAGOON
Case Study 1 1s a disposal area for wastes from a defunct refinery.
5.1.1 Site History
The petroleum waste site resulted from years of dumping bottom sludge
from refinery vessels and tanks at a disposal area located adjacent to the
refinery. The on-site disposal activity was performed as general refinery
upkeep and was typical of the oil industry at that time.
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This small refinery was located 1n Southern California between the
foothills of a mountain range and a small community. The refinery dumped Its
wastes on site from about 1930 to 1950. In 1952, the refinery was dismantled
except for an old garage and several tanks. Since 1953, the site has been a
crude oil pumping station. No known dumping has resulted from the pumping
station operation; therefore, all waste dates back over 35 years. At present,
the property 1s separated from an elementary school and a number of residences
by a fence and a drainage channel. The site 1s shown In Figure 22.
The refinery dumped most of Its sludge 1n a landfill on the western edge
of the property. The landfill covered approximately one acre of surface area
and was bermed at the middle at some unknown time, thereby separating the
landfill at the north end from a lagoon at the south end. The landfill is
believed to have resulted from dumping soil Into the landfill to solidify the
liquid waste. Investigations of the site disclosed that the entire
landfill/lagoon contained roughly 11,100 cubic yards of waste to a depth of
*i
about 6 feet. The waste was an oily sludge, with an odor and appearance
typical of refinery wastes.
The site 1s subject to hot summers and mild winters. Precipitation is
approximately 20 Inches per year, occurring p, .dominantly during the winter
months. During site work, winds generally were light and easterly or
northeasterly during cooler periods. During warmer periods, onshore sea
breezes yielded moderate breezes from the west and southwest. The residential
neighborhood was downwind of the lagoon and landfill most of the time.
5.1.2 Ob.iectives
The objectives of the site work, from an air pathway perspective, were
several-fold: provide estimates of the undisturbed and disturbed site
emissions; to use BEEs to develop a mitigation plan; and to conduct ambient
monitoring during the remedial investigation and mitigation to ensure worker
and community protection through the setting of appropriate action levels.
138
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N
+ 30-foot Meteorological Tower
A 10-foot Meteorological Tower
^^ Suspected Disposal Areas, 1-8
0 tOO 200 300 400 500
FEET
Figure 22. Location of suspected disposal areas.
139
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Table 14 summarizes the activities conducted at the site to address the air
pathway. These activities are described below.
5.1.3 Scoping
In late 1980, the owner sought regulatory agency approval to remove the
waste and apply It to site roads. California's Regional Water Quality Control
Board denied the request after two sets of samples, sent to two Independent
laboratories, disclosed high lead concentrations In the waste. The owner then
sought a more thorough environmental evaluation of the site and
recommendations for remediation.
*
The Initial task In completing the scoping phase of the site
characterization was a review of existing data. Information was collected
from the owner's site files, from files at a similarly operated refinery, from
public agencies, and from available references. The collected data were
reviewed to provide a working'knowledge of the site history, conditions, and
environmental setting. Essentially no activities had been conducted to
determine waste volume, environmental Impacts, emissions characteristics, or
waste existence and type in other suspected disposal areas.
The site Investigation was Initiated by a site Inspection. The
inspection served to familiarize the crew with the site, to locate special
features, and to assist in the development of appropriate sampling methods.
This undertaking Identified two types of wastes: a tar-like waste and a
granular waste that gave off fumes and white vapors when It came in contact
with water. The granular waste caused eye Irritation and hindered breathing.
Based on this site scoping, the potential for volatile air emissions during
site mitigation was deemed to be high and further site characterization
activities were initiated.
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TABLE 14. APA ACTIVITIES CONDUCTED AT THE SITE
APA Objectives
Determine the baseline and disturbed emissions for the site using direct
emission measurement technologies. Protect on-s1te workers and the public
from air emissions during the Investigation by using air monitoring and action
levels to stop site work.
? Scoping
The lagoon and landfill were determined to contain petroleum waste that had a
moderately high volatile organic air emissions potential. Partlculate
emission potential from the sludge/tar-like solid waste was considered to be
low.
Screening Measurements
The site was surveyed using real-time Instruments (Indirect technology) for
"indicator compounds on a grid system. Soil samples were collected for head
% space analyses to assess air emissions potential (direct technology). These
data were used to design the In-depth measurement strategy.
*;
In-Depth Measurements
-**% *- - ^ T- III I I
The In-depth emission measurements Included:
Undisturbed baseline emission measurements using the surface
emission Isolation flux chamber;
Disturbed baseline emission measurements using the downhole emission
chamber; and
Air monitoring for worker and public protection.
These data were used to develop undisturbed and disturbed site BEEs.
Mitigation
Undisturbed and disturbed BEEs were used to develop a remedial alternative
that Included excavation and removal of the waste and air emissions control
technologies.
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5.1.4 Overview of Fieldwork for Site Characterization
An undisturbed emission survey (see 5.1.5) was completed to assess the
atmospheric Impacts of volatilized compounds under prevailing site conditions.
The emission survey used Indirect real-time Instrument measurement techniques.
Knowledge of the type of waste Indicated that total hydrocarbons and benzene,
as representative of aromatic species, were good Indicator compounds for
volatile emissions from the petroleum waste. It was also possible that sulfur
dioxide (S02) could be an air contaminant from the waste. Thus, total
hydrocarbons, benzene, and S02 were selected as the Indicator compounds.
Other compounds may have been equally well suited for use as Indicators, but
the compounds selected proved to be adequate. Testing for these compounds
showed low emissions (less than three times background levels)"of total
hydrocarbons, benzene, and S02. This result was obtained by comparing on-site
emission rate data to background or off-site data. It was concluded that no
significant atmospheric Impacts existed on or off site for undisturbed site
conditions.
To assess the potential impacts of air emissions of the combined site
during remediation and to provide adequate monitoring for on-site personnel
and nearby residences, a monitoring program was conducted that included:
constant meteorological monitoring at two stations; monitoring for emissions
rfrom waste disturbance activities at the property boundary between the waste
and the nearby residences; and surveying of corehole borings.
Two meteorological towers (see Figure 22) were used to collect continuous
data. A 33-foot tower equipped with meteorological instrumentation collected
the primary meteorological site data during the field activity. In addition,
a 10-foot tower provided micro-meteorological wind speed and wind direction
data. The towers were positioned upwind and downwind of the landfill and
lagoon. Meteorological data were used in receptor modeling, in conjunction
with the measured emission rate data, for planning remedial options.
Additional waste characterization efforts were performed. Five core
holes were drilled through the waste and into the soils below the waste to
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permit sampling of the waste and soils and examination of waste and soil
stratification and physical properties. They also provided a means for
measuring volatile species emissions as a function of depth In the waste.
Wastes were found to be only 5 or 6 feet deep over the 50,000 square-foot pit
area, for a total of approximately 11,100 cubic yards of wastes 1n the
landfill and lagoon. Hastes were generally soft and semi-fluid 1n the lagoon
and hard or soil/waste mixtures In the landfill. The waste had a pH below
2.0, contained varying levels of trace metals (Including high concentrations
of lead 1n some samples), and had a very high percentage of organic material.
Soils below the wastes were predominantly alluvial gravels mixed with sand and
silt. The soils rapidly buffered acidic waste leachate. Trace metals were
found in varying concentrations and no apparent trend existed with depth. The
underlying soils had been Impacted by low levels of hydrocarbons originating
in the waste pit.
In addition to the air-related work described above, extensive work was
undertaken to assess the Impact of the site on local ground water. Also,
eight small areas suspected of being former waste disposal areas were
Investigated.
The site Inspection data were reviewed and a subsequent site
Investigation plan was developed. This Included an undisturbed emission
survey, air monitoring on-s1te and at the fence!ine during drilling and
sampling of wastes in the landfill and lagoon, and an emissions survey under
disturbed conditions to estimate the potential for emissions during possible
future disturbance of the wastes during an excavation activity.
5.1.5 Undisturbed Emissions Survey
Both screening and In-depth measurements were performed.
Screening Measurements--
A survey of the undisturbed surface emissions was conducted. First, the
main waste piUdisppsal areaowas surveyed and a map was prepared with a grid
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system overlying the waste area to provide location reference. An emissions
survey was performed which consisted of a real-time Instrument survey (an
Indirect measurement screening technology) for Indicator species at randomly
selected grid points mapped over the landfill and lagoon. This survey
provided general data on the level of gas concentrations from the landfill and
lagoon, Identified potential areas of higher concentrations, documented
background conditions (I.e., gas species concentration background levels), and
provided Input Into the safety program, ensuring adequate worker/operator
protection. This screening technology was selected because 1t was a quick and
Inexpensive way to survey the site for areas of high air emissions potential.
These data could then be used to design the in-depth measurement approach.
During the emission screening, portable, real-time monitors were used to
determine sulfur dioxide (S02), total hydrocarbon compounds (THC), and
aromatic compounds (benzene). THC measurements were made with an organic
vapor analyzer (OVA). S02 measurements were made with an electrochemical cell
instrument. The HNU analyzer was used to detect aromatic species reported as
benzene. S02, THC, and benzene, as well as surface and air temperature, were
measured at 27 grid node points under quiescent conditions. The portable
analyzers provided rapid feedback, but could not differentiate between various
hydrocarbon or sulfur species.
; For this site, benzene, S02, and THC were used as Indicators of air
emissions. Benzene Is a carcinogenic contaminant representative of aromatic
compounds. Sulfur dioxide was a possible Inorganic air contaminant on site.
Total hydrocarbons were monitored for an Indication of total organic air
emissions.
In-Depth Measurements-
After completion of the screening measurements, in-depth measurements
were conducted to quantitate the gas emissions from the undisturbed site for
risk assessment purposes and to aid in siting drilling locations. The need
for this type of sampling was determined before any screening measurements
were performed, based on the waste type and the proximity of receptors (i.e.,
the suspected large volume of highly volatile wastes was considered likely to
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cause significant air Impacts during any remedial waste removal or disturbance
activities). Direct emission measurements were performed using an emission
Isolation flux chamber. This 1n-depth technology was selected because 1t Is
Ideally suited to obtain emission rates from homogenous area sources. The
flux chamber Is relatively easy to use and multiple measurements (I.e., 8 to
10) can be obtained 1n one day. Gas samples collected from the flux chamber
outlet line were analyzed using real-time analyzers. Samples also were
collected in gas canisters for detailed hydrocarbon speciation 1n an off-site
.laboratory.
The site was divided into zones of high and low emissions potential based
on plotted results from the real-time instrument survey. Locations for in-
depth measurements were randomly selected from grid cells in these different
zones. Based on the results of the real-time Instrument survey, nine flux
chamber measurements were performed to assess the undisturbed emission from
the main landfill/lagoon. The flux chamber was constructed and operated as
.described in Section 4. Measurements at a,given grid point were typically
made over a 40-minute time period.
Chemical measurements performed on the air leaving the emission chamber
included:
Continuous determination of S02 (InterScan);
Continuous determination of THC (OVA);
Continuous determination of benzene (HNU); and
Grab sampling for organic speciation (Photovac 1010).
Undisturbed Emission Survey Results--
A total of 27 grid nodes were sampled, including sampling at five
background locations (upwind of each block), five duplicate sample points, and
sampling at one control point location at three different times of the day
(morning, noon, and afternoon). The control point was one of the grid points
that was regularly sampled to establish an estimate of the temporal
variability In emissions at the site.
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Very low gas concentrations were observed over the exposed waste. Most
of the screening measurements showed background levels at the locations
sampled for S02, THC, and benzene as shown In Table 15. Moderately low levels
of undisturbed emissions were observed over exposed waste In the lagoon and
the landfill. Table 16 provides undisturbed site emissions data.
The results of the screening and 1n-depth emissions testing showed that:
The emissions were highest 1n the landfill and lagoon where wastes
were exposed (especially where natural disturbances occurred; I.e.,
cracking of surface, waste seeps, etc.);
Control point sampling at various times of the day ("same location)
Indicated a large temporal variation in emissions due primarily to
solar surface heating;
Areas surrounding the combined site or 1n overburden on top of the
waste material showed background levels of emission; and
Volatile emission rates from the combined site (landfill and lagoon)
were low for S02 and benzene under undisturbed conditions. For
steady-state conditions: S02 emission rates ranged from background
to 5.6 ug/m2 minute"1; THC emission rates ranged from background to
120 ug/m2, minute"1; and benzene from background to 470 ug/m2,
minute"1. Emissions did show a high dependence on diurnal
temperature fluctuations with more emissions observed during the
hottest periods, as expected. The field photovac analytical
capability provided limited hydrocarbon speciation data that helped
direct more detailed hydrocarbon sampling and analysis. The
photovac data were not used to determine emission estimates.
5.1.6 Disturbed Emissions Survey
Both screening and in-depth measurements were performed.
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TABLE 15. SUMMARY OF SCREENING MEASUREMENTS OF UNDISTURBED WASTE
Range of Values
Number of SO., (mm) THC loom) Benzene (pom)
Measurements Peak Average Peak Average Peak Average
41 0.005 0.005 2-4a 2-4' 0.01-0.80b 0.01-0.70b
a Differences probably due to Instrument drift.
b Background levels only detected at 30 of 41 points.
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TABLE 16.- CASE STUDY 1: SUMMARY OF UNDISTURBED SITE EMISSIONS DATA
Lagoon S02 THC* Benzene6
Location
(Surface) (mg/m2, rain'1) (ug/m2, mln"1) (ug/m2, mln'1)
II 0.14 1.8 4.7
12 0.14 120 470
#3 0.14 7.3 43
#4 0.14 44 1.8
15 5.6 7.3 _U
a As determined by portable FID (OVA).
b As determined by portable PID (HNu).
Average 1.2 36 98
Landfill
Location
#1
n
Average
0.14
U_
0.77
7.3
2i_
18
3.6
1^
3.6
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Screening Measurements--
Samples of soil/waste were collected during drilling at each sampling
point as part of the screening survey. Screening for volatile organic
compounds (VOCs) in these samples was performed at the field site with a
Photovac 1010 portable photoionization gas chromatograph (GC). This GC has
part-per-billion (ppb) level sensitivity for mi Hi liter volumes of air. Soil
and waste samples were collected (2 to 3 grams) and stored in 40 ml VOA vials
with Teflon\ SEPA. The vials were equilibrated in a 30*C water bath for 30
minutes prior to the head space analysis for VOCs. This sampling procedure is
considered a direct measurement screening-technology.
During disturbance activities, fenceline monitoring for S02 and benzene
was conducted using portable real-time instruments. Also meteorological
conditions were monitored during all work disturbing the site. Action levels
were established to require cessation of site activities if exceedances were
noted (none occurred) to protect the local community.
Downwind and border monitoring consisted of three activities:
S02 and THC were monitored immediately downwind of the disturbance
activity;
S02 and THC were monitored at a mobile unit approximately 40 feet
downwind of the Initial disturbance activities; and
S02 and benzene were monitored at a mobile unit at the.downwind
fenceline between the drilling operation and the nearby residences.
Standard monitoring procedures (see Volume IV of this series of manuals) were
used in operating the border and downwind stations. Air analyzers were
operated according to written quality control protocols and continuous data
printouts were collected using strip chart recorders. The monitoring stations
were positioned each day based on wind direction data from the meteorological
stations.
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In-Depth Measurements--
Downhole emission measurements at various depths 1n the waste were
conducted during drilling activities to determine an emissions "profile" In
the waste. These data were used to characterize the waste properties and to
predict potential gas emission from the wastes 1f they were excavated.
Downhole emissions measurements were performed using the direct emissions
measurement technique (I.e. downhole flux chamber). This technique 1s
considered an 1n-depth measurement technology and was applicable for the
landfill and the lagoon. The plexlglas chamber had an exposed surface area of
0.00318 m2. The chamber Input and output lines were 40 feet long,
facilitating flux measurement to 30 feet below land surface.
»
Five locations for drilling were selected as part of the solid waste
Investigation. They are shown 1n Figure 23. They were representative of
waste bodies and were equally spaced across the waste areas. Hydrocarbon
samples were collected in 2.8-liter stainless steel canisters. After
collection, the canisters were shipped to an off-site laboratory for analysis.
A total of 18 downhole emission measurements were performed and realtime
data for S02, THC, and benzene were collected at each point using the real-
time analyzers. Canister samples were collected at six locations (at various
depths within the five core holes) for speciation analyses. Canister samples
were not collected at all sampling locations in an effort to conserve project
resources. The Indicator compounds were used to represent air emissions
potential in the absence of the canister samples.
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Figure 23. Location of waste soil coreholes.
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Disturbed Emission Survey Results--
The results of air monitoring conducted during drilling are summarized in
Table 17. The results of border and Immediate downwind monitoring for
disturbed site activities Indicated no significant Impact from fugitive
emissions downwind from the site (northeast) boring activities. Even though
the disturbed waste had a high emissions potential, small amounts of waste
were exposed 1n the drilling operations following the conservative operating
procedure. The border station was positioned on the west border to ensure
neighborhood safety. This location also provided valuable onsite safety
Information for site operations personnel.
The results of the downhole emissions survey Included peak and steady-
state emissions for S02 and THC at the given depth. Benzene data were not
.collected due to the lack of an extractive pump in that analyzer that could
pull the sample through the long sampling lines. The steady-state values are
more representative of the level of emissions expected Involving a disturbance
of the waste (I.e., removal). Data results are presented 1n Table 18 to
illustrate the S02 and THC emissions observed as a function of the type of
waste/soil. This format Illustrates the relative emissions characteristics of
S02 and THC per depth in the cores as well as the emission tendencies of the
waste/soil. A comparison of peak to steady-state emission values is used to
identify emission sources in the waste pit (I.e., limit of vertical
.contamination).
Volatile emission rates from the site under disturbed conditions were
higher than the undisturbed site and demonstrated potential for volatile
emissions during waste disturbance activities. The S02 emission rates under
disturbed conditions ranged from background (1.6 EE4 ug/m2, minute'1) to 1.1.
EE6 ug/mz, minute'1, and the THC emission rates ranged from 3.8 EE3 ug/m2,
minute"1 to 3.8 EE6 ug/m2, minute"1. The results of the hydrocarbon speciation
analyses Indicated the following hydrocarbon composition:
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TABLE 17. DOWNWIND/BORDER MONITORING RESULTS
Location
West Border
(Fence)
Core S-l
Downwind
40 m
Core S-2
West Border
(Fence)
Core S-2
West Border
(Fence)
Core S-3
West Border
(Fence)
Core N-l
West Border
(Fence)
Core N-2
Date
08/02/83
08/02/83
08/02/83
08/03/83
08/03/83
08/03/83
08/05/83
08/05/83
08/08/83
08/08/83
08/09/83
08/09/83
Species
Benzene*
S02b
Benzene
S02
Benzene
S02
Benzene
S02
Benzene
S02
High Leveld
(ppmv)
0.12C
Background
Background
Background
Background
Background
0.35
0.12
0.12C
Background
0.16°
Background
Duration
Elevated
Background
<5 minutes
* Benzene Instrument (HNU) background typically 0.1 ppmv.
-
b S02 Instrument (InterScan Analyzer) background typically 0.05 ppmv.
c Reading attributed to Instrument drift.
d Background refers to Instrument reading 1n "clean" air.
153
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Hydrocarbon Class
Average %
Ranoe %a
Alkanes
Alkenes
Aromatics
Oxygenates
Halogenated
Sulfonated
Unidentified
"5 cores, 6 canister samples
79.0
15.0
4.2
0.62
1.2
NO
2.0
68 - 87
0.87 -
2.4 -
0.15 -
0.091-
ND
0.42 -
21
8.1
1.5
3.3
6.6
These data show that most of the air emissions were alkane species and of no
significant concern regarding toxicity. The aromatic fraction was, as
expected, around 5 percent, and was composed of numerous compounds.
5.1.7 Development of BEEs
Calculation of baseline emission estimates (BEEs) can be developed from
either ambient concentration data (indirect techniques) or from emission irate
measurement data (direct techniques). BEEs can be calculated for each
contaminant species detected or for a group Table 18 of contaminant species.
BEEs obtained from direct measurement techniques which provide rate data
(i.e., mass per unit time per given surface area) are preferable. The BEE is
normalized for the area of the source and has units of mass of contaminant or
group of contaminants per time.
BEEs can be calculated from individual emission sources and summed for
sites containing multiple emission sources (operable units), such as a lagoon
and a landfill with each source characterized by different air emission rates
and contaminant species.
The calculation of an undisturbed emission estimate for this site
Included the following considerations. The site consisted of a waste area
containing a landfill in the northern portion and a lagoon 1n the southern
portion, separated by a berm. Each portion of the site was evaluated
separately. Undisturbed emission factors for each of the two operable units
were calculated separately and then averaged to provide an overall site
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emission estimate. The undisturbed emission rates for the lagoon and the
landfill, and the combined site emission estimate calculations are presented
below.
The undisturbed BEE for the lagoon (average) was calculated for S02 and
THC. The surface emission Isolation flux chamber survey results from five
single measurements were averaged by species and multiplied by the lagoon
surface area to determine the unit BEE.
Lagoon BEE$0 - (I.2ug/m2-m1n)(6860 m2) - 8.2 x 103 ug/m1n of S02
Lagoon BEETHC - (36 ug/m2-m1n)(6860 m2) - 2.5 x 10s ug/m1n of THC
Similarly, the BEE for the landfill operable unit (average) was calculated for
S02 and THC. The emission Isolation flux chamber survey results were averaged
for each species and multiplied by the surface area of the landfill to
determine the unit's BEE.
Landfill BEE$0 - (0.77 ug/m2-m1n)(7240 m2) » 5.6 x 103 ug/m1n of SO
Landfill BEETHC - (18 ug/m2-min)(7240 m2) - 1.3 x 10s ug/m1n of THC
The overall site BEE (for S02 and THC) can be obtained by summing the
respective unit BEEs by species.
Calculation of emission estimates for disturbed site conditions can be
performed from either air monitoring data (concentration measurements) during
waste disturbances or from direct emission rate measurement data.
Concentration values can be expressed as a concentration (ppm-v) for each
species, as a ratio of the species concentration to the total concentration
from all species, or as a percentage value for the species of Interest over
the total concentration contributed from all other species. The disturbed
site emission flux data has the units of mass per time per unit area.
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The emission estimate 1s calculated by multiplying the average measured
emission rate by the total surface area of disturbed material. This results
In a single value of mass per unit time which provides a relative estimate of
the rate of air emissions from the source. Emission estimates can be
calculated for a site with either Individual sources or with multiple sources.
These operable units often are Investigated and remediated Independently.
Emission estimates for a combined site can be calculated by using the highest
disturbed emission estimates for each source and summing the emission per time
for each source.
Summaries of the average disturbed emissions flux for both units of the
Case Study 1 site are presented below:
*
Landfill
S02 - 9.2 x 102 (ug/m2-min)
THC - 1.7 x 103 (ug/mz-m1n)
Laooon
S02 - 2.9 x 103 (ug/m2-m1n)
THC - 6.4 x 103 (ug/m2-m1n)
These data can be used 1n conjunction with estimates of exposed disturbed
waste to predict air Impacts from various waste disturbance and treatment
technologies.
Examole
Excavation of the landfill would typically expose 50 m2 of waste at a
time. The estimate of THC air emissions from the site activity would be:
THC (landfill) - 1.7 x 103 (ug/m2, minute'1) x 50m2
8.5 x 10s (ug/min)
Depth-specific Information could be used to provide area and depth-specific
emission estimates as needed.
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5.1.8 Summary
The Case Study 1 Investigation was generally a thorough, well documented
study that fully addressed the air pathway for volatile contaminants. The
study followed closely the steps outlined 1n this manual's protocol and all
objectives were met. Furthermore, site personnel report that the knowledge of
the potential for emissions, ultimately resulted In a safer and more cost-
effective remediation of the site. BEEs were used 1n risk assessment and in
designing removal plans. Air emission control technologies were selected
based on the BEEs.
5.2 CASE STUDY 2; BRUIN LAGOON
Case Study 2 1s a disposal lagoon that received various wastes from a
mineral oil refinery. This site was under remediation 1n 1984 when subsurface
gases were unexpectedly released during cleanup. Work was halted and the
remedial design was reassessed. A second Remedial Investigation/Feasibility
Study (RI/FS) was then performed. This case study focuses on the APA
conducted during this second RI/FS (see Table 19).
5.2.1 Site History
Bruin Lagoon 1s located about 45 miles north of Pittsburgh, In Bruin
Borough of Butler County, Pennsylvania. The 4-acre site 1s situated along the
western bank of Bear Creek's South Branch, approximately 7 miles upstream of
the creek's confluence with the Allegheny River. Part of the site lies within
the creek's 100-year floodplain. To the west, the site 1s bordered by private
homes and State Route 268. Bruin Borough's main residential and commercial
areas are within five blocks of the site and more than 30 residences are
within 500 feet of the lagoon. To the south Is an abandoned refinery, which
is the source of the wastes deposited in the lagoon. Also, adjacent to the
site are two ponds and a small stream that drain into Bear Creek.
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TABLE 19. APA ACTIVITIES CONDUCTED AT THE CASE STUDY 12 SITE
APA Objectives
Assess the extent and composition of subsurface gas pockets. Monitor the
ambient air for health and safety reasons.
Scoping
Initially, the lagoon was determined to contain wastes that had minimal
potential for volatile or participate matter emissions (first RI/FS). The
second RI/FS did assume that volatile emissions from subsurface gas pockets
were likely.
Screening Measurements
A variety of portable, real-time analyzers and detector tubes were used to
monitor the ambient air during drilling activities. Monitoring took place at
the site perimeter and in the ambient breathing zone near the drill rig. Soil
samples were collected and the emissions from the samples were scanned. The
screening data were used to design the in-depth measurement strategy.
In-Deoth Measurements
The in-depth emission measurements Involved collecting and analyzing grab
samples of gas from boring/wells whenever the ambient breathing zone
monitoring showed elevated concentrations significantly over background
levels. However, these data were not used to develop undisturbed and disturbed
site BEEs.
Mitigation
The disturbed waste emissions data were used in the development of the
remedial action plan. Although disturbed emission rates were not calculated,
knowledge of areas considered to be "hot spots" were used to conduct site
operations in a way that prevented major releases of air toxics to the air.
The remedial alternative Included gas monitoring during on-site stabilization
and neutralization of the unstabilized sludge and collecting, venting, and
treating as necessary.
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Currently 1n remediation, Bruin Lagoon 1s an unllned earthen diked lagoon
that has been partially covered with 9300 cubic yards of stabilized soil/
sludge mixture treated during the first attempt at remediation. Beneath this
material 1s approximately 17,200 cubic yards of unstab111zed sludge/tar, with
up-welling of the waste 1n a number of areas. The sludge/tar contains
sulfurlc acid and heavy metals, along with other contaminants. The lagoon
area of the site Is generally level and lacks vegetation. A cross-sectional
view of the site Is shown 1n Figure 24.
Bruin 011 Company, producer of white (mineral) oil, began disposing of
Its wastes at the lagoon In the 1930s. This continued for more than 40 years.
Materials discarded there Included:
*
Residues scraped from crude oil storage tanks;
Used bauxite, charcoal filtering agents, and bone powder;
011s not meeting specification;
Coal fines;
Lime;
Spent alkali; and
Boiler house coal and ashes.
The lagoon attracted national attention 1n 1968 when about 3,000 gallons
of acidic sludge spilled Into the South Branch of Bear Creek through a breach
in the dike. In the Allegheny River, roughly 4 million fish died and many
downstream communities temporarily lost their water supplies. The spill was
addressed, but the remedial investigation of the site didn't begin until 1981.
The abandoned refinery and the lagoon were owned by AH & RS Coal Company,
which underwent bankruptcy proceeding in 1986.
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5.2.2 Objectives
The objectives of the site work, from an air pathway perspective, were
two-fold: to monitor the ambient air for health and safety reasons; and to
assess the extent and composition of subsurface gas pockets. To meet the
latter objective, sampling and analysis of vapors contained 1n the shallow
wells were performed to: Identify the composition and extent of gases trapped
under the site; determine their regeneration rates; and assess the potential
for their release Into the atmosphere during remedial construction work.
5.2.3 Scoping
The existing data were reviewed to provide a working knowledge of the
?.site history, conditions, and environmental setting. Based on this review, no
specific potential emission characterization was called for in the first
RI/FS. After unexpected emissions were encountered when drilling through the
bottom of the lagoon during remediation, the second RI/FS did address the air
pathway to a greater extent.
5.2.4 Overview of Fieldwork For Site Characterization
EPA contractors began what would become the first RI/FS at Bruin Lagoon
in July 1981. Air monitoring during this remedial investigation failed to
find detectable levels of organics, sulfur dioxide (S02), hydrogen sulfide
(H2S), hydrogen chloride (HC1), or hydrogen cyanide (HCN) in ambient air at
the site. Although one well boring showed organic vapors during drilling
^operations, the levels were not detectable at the ambient breathing zone.
Significantly, no borings through the open lagoon were performed in this
initial effort.
With the RI/FS completion in January 1982, EPA and the Pennsylvania
Department of Environmental Resources (PADER) selected a remedial, alternative
that Included sludge stabilization, dike reinforcement, debris removal, and
construction of a multi-layer cap to cover the lagoon. Design kicked off in
September 1982 and cleanup actually started in August 1983.
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The project proceeded until Nay 4, 1984, when hazardous gas and acid mist
escaped from an unanticipated crust, thought to be the bottom of the lagoon,
that was broken during mitigation. These organic vapors and sulfur dioxide or
hydrogen sulflde reached the ambient breathing zone but were not detectable at
the site perimeter. Gas sampling was performed for worker and public
protection. Gas samples from beneath the crust revealed high concentrations
of carbon dioxide, hydrogen sulflde, and sulfuric add mist. Consequently,
EPA suspended cleanup activities and Immediately launched 1n emergency
response, which Included some removal, covering the lagoon with stabilized
sludge, Installing 13 shallow gas monitoring wells, and collecting and
analyzing additional sludge and soil samples.
The site remained in the emergency mode until September 1984. The second
RI/FS was Initiated the following January. Air monitoring conducted
throughout this RI Included:
Health and safety;
Site perimeter;
Ambient breathing zone;
Downhole concentration sampling and analysis; and
Sample screening.
Conclusions drawn from a review of all of these activities (the two RI/FS
endeavors and the emergency action) Included Identification of a "hot spot" in
the unstabilized portion of the lagoon that contained carbon dioxide, hydrogen
sulfide, sulfur dioxide and methane at levels deserving attention during
remediation. The RI/FS concluded, however, that subsurface gases were not
present throughout the site. To address the "hot spot" the remedial
alternative selected in September 1986 Included gas monitoring, venting, and
treating during excavation, followed by post-closure monitoring.
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5.2.5 Undisturbed Emissions Survey
Based on the available documentation, no screening or 1n-depth mea-
surements were made to assess the undisturbed emission at the site. Since the
site contains heavy metals and 1s unvegetated, an evaluation of the entrained
partlculate matter from the site would have been advisable, and some screening
measurements for particulates and Inorganic gases may have been warranted.
Some air monitoring was performed Immediately prior to site disturbances.
These limited data do address, undisturbed emissions.
5.2.6 Disturbed Emissions Survey
Both screening (air monitoring and sample headspace) and in-depth (soil
vapor well) measurement techniques were used to assess the emissions during
site disturbances such as drilling. The following discussions are largely
taken from the second RI/FS prepared for the Bruin Lagoon site (59).
Screening Measurements--
The following air monitoring equipment was available on site during all
drilling activities:
HNU photoionization detect>r (PID) with 11.7 and 10.2 eV probes;
OVA (organic vapor analyzer) flame ionization detector (FID);
H2S portable gas monitor;
S02 portable gas monitor;
H2S monitor alarms;
Explos1meter/oxygen monitor; and
Detector tubes S02, H2S, H2S04, 02, C02, natural gas.
Based on gases detected in past site work, portable direct reading real-
time Instrumentation was primarily used for gas characterization and health
and safety purposes. Detector tubes were used for screening of possible
instrumentation interferences, confirmation of direct reading concentrations,
and analysis of gases not detected on available instrumentation.
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The direct reading monitoring Instruments determined to be most effective
for monitoring drilling operations were the HNU PID (11.7 eV), H2S portable
gas monitor, H2S monitor alarms, and S02 portable gas monitor. The HNU PID
was selected over the OVA FID due to the sensitivity of this Instrument to
hydrogen sulflde gas. The HNU PID could detect both hydrogen sulfide gas and
organic vapors. This selection was made because of past historical data
demonstrating possible H2S gas release.
Periodic monitoring of ambient air at the site perimeter was routinely
performed during drilling operations. Also, 1f ambient breathing zone
concentrations Indicated possible gas releases, perimeter monitoring was
Immediately Initiated. Seventeen monitoring locations were established along
the site fence line at intervals of approximately 150 feet and'marked with
stakes. Figure 25 shows the perimeter monitoring locations. Perimeter
monitoring was conducted with the H2S and S02 portable gas monitors and the
HNU PID.
During all drilling operations, the H2S and S02 portable gas monitor, H2S
monitor alarms, explosimeter/oxygen monitors, and HNU PID were used for
characterization of the ambient breathing zone. Background levels were
determined prior to starting the drilling.
Portable Instrument readings provided continuous, real-time monitoring of
each split spoon and drilling depth to determine at what depth, if any, gas
releases occurred. Each split spoon and core sample was scanned with Figure
25 all direct reading instrumentation immediately after collection. Samples
showing positive readings were usually selected for chemical analysis.
In-Depth Measurements--
If ambient breathing zone monitoring showed elevated concentrations
significantly above background levels, a grab sample of the gas present in the
boring/well was collected for analysis. These grab samples were analyzed to
characterize the emitted gases. Grab samples were collected from a point
approximately 3 feet below the ground surface by Inserting tubing Into the
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boring/well and pumping the gas Into an air bag collector. The bag sample was
then sealed and analyzed on-s1te using available Instrumentation and detector
tubes.
Disturbed Emission Survey Results
The following results are taken from the second RI/FS prepared for the
Bruin Lagoon site (59).
A1r monitoring conducted during the 1981 remedial Investigation of Bruin
Lagoon revealed no detectable levels of organ1cs, S02, H2S, HC1, or HCN 1n the
ambient air at the site. Organic vapors were detected within one well boring
during drilling operations; however, no detectable levels were found in the
ambient breathing zone at this location. It should be noted tfiat no borings
were constructed through the open lagoon during the Initial RI and, as a
result, the gases trapped below the crust were not encountered.
Background air monitoring performed during field work in June 1984 showed
no detectable levels of H2S or methane. Air samples collected from the soil
boring Indicated the presence of H2S, C02, methane, and aromatic hydrocarbons.
S02 was not detected in the downhole samples. H2S was present in the soil gas
on the average at about 300 to 400 ppm; Initial concentrations were greater by
an order of magnitude or more.
Low levels of organic vapors, sulfur dioxide and hydrogen sulfide were
released Into the ambient breathing zone when the subsurface of the site was
disturbed by drilling operations. S02 concentrations were observed as high as
50 ppmv but typically were found at 0.5 to 18 ppmv in the breathing zone
during drilling operations. H2S concentrations were lower with high
concentrations observed at 14 ppmv with typical concentrations of 1 to 10
ppmv. However, concentrations of these gases were not detectable at the site
perimeter.
The analytical results for the subsurface gas samples collected from the
13 shallow wells Installed during the 1984 emergency action showed various
concentrations of volatile organics, S02, H2S04, and methane 1n the wells.
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Methane was observed in all the wells ranging from 2.6 to 4,400 ppm. These
concentrations showed good correlation with the organic CH4 levels measured 1n
the field by the OVA. Analysis of carbon tube samples collected for each well
showed no detectable volatile organic compounds. Sulfur dioxide was found to
be present 1n 11 of the 13 wells, with four wells having S02 concentrations
greater than 100 ppm.
The results of the 1984 sampling of subsurface gases at the Bruin Lagoon
site showed elevated levels of S02. The presence of H2S04 mist was limited to
three wells (A-8, A-10, and A-13). Additionally, reactions and gas releases
occurred during the Installation of each of these wells. Elevated levels of
S02 also were detected in well A-2. These wells are all located within 50
feet of one another, and, as a result, the data suggest that this area of the
site 1s a "hot spot" with respect to potentially harmful trapped subsurface
gases. Additional sampling one year later confirmed the presence of a "hot
spot" area located in the central part of the site.
5.2.7 Development of BEEs
No baseline emission estimates or disturbed emission estimates were
generated. It was noted, however, that remediation may result In the release
of pockets of hazardous gases trapped below a crust at the bottom of the
lagoon. BEEs would allow performance of risk assessments for various release
and meteorological scenarios at receptor points of Interest.
Given the available data, the best method for determining BEEs for this
site would be to take the existing ambient air monitoring data and back-
calculate an emission rate using an air dispersion model. This Is done by
setting up the model's run conditions to match those at the site as closely as
possible, and then varying the source term to find an emission rate that
produces downwind concentrations equal to those actually measured. Using the
respective air monitoring data sets, this procedure could be used for both
undisturbed and disturbed conditions. However, the accuracy of this procedure
is limited by the amount and representativeness of the available air -
monitoring data. ,
168
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5.2.8 Summary
The Case Study 2 Investigation points up the need to consider potential
emissions from the disturbed site before any remedial actions are undertaken.
Here, no soil borings through the open lagoon were performed during the first
RI/FS. The initial failure to do so, or to even consider potential air
..emissions at this site, resulted in the need for a second RI/FS and associated
: schedule delays and extra expenses. The study did not closely conform to the
steps outlined in the protocol of this manual. No undisturbed emission
measurements were performed (beyond some background air monitoring) and no
emission rate data were collected.
*
The best technology for screening particulate matter (PM) emissions at
this site would have been to collect upwind/downwind samples on filters using
.high-volume sampling pumps (hi-vols). The total particulate matter present in
the air would be determined by dividing the filter weight gain by the volume
;of air sampled. Analysis of the filter catch for selected metal species would
assist in assessing the health Impacts from undisturbed emissions. A less
acceptable alternative would have been to measure the ambient particulate
-matter loadings using a portable particulate matter analyzer. The activities
conducted, however, provided valuable data that were very useful in the
design, selection, and implementation of the remedial alternative.
5.3 CASE STUDY 3: LOWRY LANDFILL
Case Study 3 is an active municipal landfill that formerly also accepted
liquid and solid industrial wastes and domestic sewage sludge. This case
'.study focuses on APA activities conducted at the site (see Table 20).
5.3.1 Site History
The Lowry Landfill is co-owned by the City and County of Denver,
Colorado. It opened for business as a municipal landfill in 1965. The site
is located about 20 miles southeast of Denver and two miles east of the City
169
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TABLE 20. APA ACTIVITIES CONDUCTED AT THE CASE STUDY 13 SITE
APA Objectives
A soil gas study was conducted to locate waste pits, determine the extent of
off-site subsurface gas migration, and determine the waste pit contribution to
such migration. An air monitoring program was conducted to measure ambient
air pollutants during Installation of monitoring wells 1n the waste pits.
Scoping
The landfill was determined to contain both hazardous and municipal wastes.
The generation of off-gases from the wastes was considered to be a hgih
probability.
Screening Measurements
The ambient air was monitored upwind and downwind of the site during
monitoring well Installation. Samples were collected using a variety of
adsorption media. Soil samples were collected and the emissions from the
samples were scanned.
In-Depth Measurements
The in-depth emission measurements Involved collection of soil gas samples at
a large number of points using vapor monitoring wells for deep sampUgn and
ground probes for shallow sampling. However, these data were not used to
develop undisturbed and disturbed site BEEs.
Mitigation
Migration plans have not yet been prepared. The site 1s currently under study
to further understand the air emissions potential from the site. These study
activites Include air monitoring at nearby receptors of concern (e.g.,
:; community school).
170
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of Aurora, 1n Arapahoe County. The site covers approximately 480 acres. The
surrounding area was mostly undeveloped when the landfill was established, but
1s growing rapidly today. (Proximity of the closest residence was not given
1n the Remedial Investigation (RI) report.
From 1965 until the advent of the Resource Conservation and Recovery Act
(RCRA) In 1980, the facility accepted municipal refuse, liquid and solid
Industrial waste (some of which was hazardous), and domestic sewage sludge.
The landfill handled these wastes by excavating pits, filling them three-
quarters with liquids and then covering the waste with refuse until a mound
several feet above the land surface was created. Landfills were dug
repeatedly, sometimes Into old, filled landfills. The landfills at the south
end of the facility were covered with as much as 30 to 60 feet of refuse.
In 1975, Continental Oil Company contracted with site owners to set up
and run an oil sludge disposal operation in the southeastern portion of the
site. This operation and the acceptance of Industrial waste stopped with RCRA
1n 1980. At that time, the City and County of Denver hired a private firm to
manage the site as a municipal waste facility only. This contractor, Waste
Management, Inc., formed a subsidiary which opened a hazardous waste disposal
facility just north of Lowry. This facility was closed In 1982.
In the early 1980s, Lowry Landfill began to be closely scrutinized by a
number of public agencies due to odor problems and other concerns. These
first cursory looks focused primarily on the groundwater contamination
pathway, studying only shallow groundwater. Not all landfills were located or
confirmed. Initial Investigations disclosed that records of types and
locations of waste were incomplete and inaccurate. Also, no measures had been
taken to prevent leachate or seepage from these pits.
Among the 60 pits Identified through aerial photographs, it was estimated
that roughly 100 million gallons of liquid wastes were disposed on-site over
15 years. Wastes Identified Include: acid and alkaline sludges; caustics and
solids; brines, Including plating wastes and other water-based sludges;
organics, both natural and synthetic, such as petroleum-based oils, grease,
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and chlorinated solvents and sludges; watersoluble oils; municipal sewage
sludge; Tow-level radioactive wastes; pesticide wastes; asbestos; and metallic
wastes.
EPA did not become Intimately Involved at the site until about 1981 when
Lowry was first considered as a candidate for the NPL. In 1984, Lowry was
placed on the NPL and formal Investigations were Initiated.
5.3.2 Objectives
At the Lowry site, a soil gas study and an air quality Investigation were
performed as part of the RI. The soil gas study was conducted to help locate
the waste pits, to determine the extent of any off-site subsurface migration,
and to determine the waste pit contribution to such migration. The air
quality Investigation was conducted to measure contaminants in the ambient air
during Installation of monitoring wells in the waste pits.
5.3.3 Scoping
Existing data were collected and reviewed to provide a working knowledge
of the site history, conditions, and environmental setting. A topographic map
of the site and Its environs was developed from aerial photos. Surveying was
performed to map sampling locations and determine the relative coordinates and
elevation of each location.
5.3.4 Overview of Fieldwork For Site Characterization
The purpose of the first phase, of a two-phase remedial Investigation,
was to characterize the site geology and climate; Identify the location and
contents of all landfills; characterize the extent of contamination, Including
air and soil gas; and Identify data gaps to be filled in during rememdial
Investigation Phase II.
Investigatory work into some of the landfills was thwarted by three piles
of vehicle tires, two piles of roughly 2 million tires each and one pile of up
172
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to 8 million tires. Findings disclosed that soil gas, air, groundwater,
surface water, and soil all were contaminated and that some migration was
occurring. To detect air contamination, contractors sampled upwind and
downwind of the site, and 50 feet downwind from the five waste pit wells
shortly after Installation (to demonstrate a worst-case emissions scenario).
The results showed that air quality was degraded as 1t crossed the site from
south to north (the direction of the prevailing wind). Volatile organic
compounds (VOCs) were detected at 0.020 to 16 parts per billion (ppb) higher
in the downwind samples relative to the upwind samples.
Separately, samples for soil gas emissions were taken from the landfills,
from gas well points and probes, and from 10 gas sampling wells installed
around the site perimeter by the contracted facility operator In 1981. The
results disclosed 19 VOCs, found in ranges of 37 to 160,000 ppb, and verified
that contaminated soil gas was migrating off-site in the vicinity of one of
the perimeter wells.
A complete meteorological monitoring station has been operating at Lowry
since April 21, 1985. It measures wind speed and direction, temperature,
relative humidity, barometric pressure, and precipitation on a 10-meter tower.
Measurements are taken by a Climatronics Electronic Weather Station (EWS)
connected to a Campbell Scientific CR21 data logger. The data are read
periodically into a mainframe DEC-10 computer.
5.3.5 Undisturbed Emissions Survey
No screening or In-depth measurements were made to assess the undisturbed
emissions at the site. However, the Phase I RI report (60) does recommend
that ambient air and meteorological monitoring be performed in the planned
Phase II work to collect background data. Based on the types of waste present
and the presence of contaminated soil gas, screening measurements (at a
minimum) would have been warranted for this site during Phase I activities.
173
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5.3.6 Disturbed Emissions Survey
Both screening (headspace sampling and upwind/downwind air monitoring)
and In-depth (soil vapor wells) Measurement technologies were used to assess
the air pathway.
Screening Measurements-
Split spoon samples collected during drilling activities were retrieved
and opened, then the air space above the samples was scanned using an HNU
portable organic vapor analyzer.
The ambient air was monitored over a 12-day period during Installation of
monitoring wells 1n the waste pits. The monitoring took pi ace"in November and
December of 1985 during which there was some snow cover; therefore, the
results do not equal a worst-case scenario. Samples were collected upwind and
downwind of the site and 50 feet downwind of the waste pit well Installations.
A controlled release of waste pit well gas was permitted to help predict
1
ambient air Impacts associated with remediation of the waste pits. Samples
were collected by concentrating air on carbon molecular sieves (CMS),
polyurethane foam, Tenax, and glass fiber filters. The sampling methods are
listed in Table 21.
In-Depth Measurements--
Soil gas samples were collected from a number of locations, Including 10
existing soil vapor wells around the perimeter of the facility and wells
installed at four locations in suspected waste pits. The wells at the waste
pits were drilled to within 2 feet of the water table. Ground probes also
were driven Into the waste pits at the same four locations to measure the gas
emanating from the waste pits and municipal refuse and reaching the near-
surface. Three more ground probes were Installed at areas without underlying
waste pits.
174
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Samples were collected from all locations using a pump to transfer gas to
, a tedlar bag within a rigid-wall container. Sample gas was extracted at
roughly 1 L/m1n for 4 to 5 minutes. The perimeter soil vapor wells required
purging (three well volumes) before sample collection; the other sampling
points had free-flowing gas.
Samples were analyzed for priority pollutants by GC/MS using EPA Method
624 at an off-site location.
Disturbed Emission Survey Results
A large data base was developed during this program and 1s summarized
here.
The upwind/downwind sampling Indicated that the site 1s a VOC emissions
source. Total VOCs on-site were 54 ppb higher than upwind values, and
downwind concentrations were 25 ppb higher than upwind values. Downwind
concentrations of acetone, carbon dlsulflde, and toluene were 3 to 10 times
the upwind values. During the controlled release, these compounds were found
at 8 to 100 times the upwind values. Other compounds, such as 1,1,1-
trichloroethane, benzene, and TCE also were found at elevated (4 to 20 times)
levels downwind. These emissions could be expected to be greatly higher
during non-winter weather conditions.
The upwind/downwind sampling showed particulate matter emissions to be a
problem at the site. The upwind values averaged 187 ug/m3 and the downwind
samples averaged 325 ug/m3 with a range of 112 to 643 ug/m3. The average
^downwind total solid participates (TSP) exceeded the Primary TSP National
* Ambient Air Quality Standard of 260 ug/m3.
Nineteen hazardous volatile organic compounds were detected 1n soil gas
samples emanating from waste pit liquid. These compounds were similar to
those found 1n the liquid samples. Concentrations ranged from 460 to 291,000.
ppb. Nineteen volatile organic compounds were found In the refuse gas
samples, 1n ranges of 37 to 160,000 ppb. Compounds were nearly Identical to
those found In gas samples above waste pit liquids except that the
17&
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concentration of compounds above these liquids was two to five tiroes greater
than In the overlying refuse and six tines greater than In refuse with no
underlying pits. It Is reasonable to conclude that the liquids and refuse are
contributing to gas contamination.
The results of perimeter well gas sampling Indicate that subsurface
, contaminant migration has occurred at Hell GPM-3 and possibly at GPM-7.
.Thirteen hazardous substances were detected In gases at Well GMP-3, near waste
pits and refuse disposal areas. Substances Included volatile organics at
ranges of 9 to 1,200 ppb.
5.3.7 Development of BEEs
No baseline emission estimates for either the undisturbed or disturbed
wastes were generated, though sufficient data exist to estimate a disturbed
.BEE. Given the available data, the best method for determining BEEs for this
.site would be to take the existing ambient air monitoring data and back-
^calculate an emission rate using an air dispersion model. This Is done by
:,setting up the model's run conditions to natch those at the site as closely as
possible, and then varying the source term to find an emission rate that
produces downwind concentrations equal to those actually measured. Using the
respective air monitoring data sets, this procedure could be applied to both
undisturbed and disturbed conditions.
5.3.8 Summary
The Case Study 3 investigation did not closely conform to the protocol
steps outlined In this manual. No undisturbed emission measurements were
performed and no emission rate data were collected. While substantial data
were collected, scheduling the air monitoring during cold temperatures and
snow cover conditions limited the data's applicability.
The best technology for screening undisturbed emissions at this site
would be to: 1) perform ambient air monitoring around the perimeter of the
facility to determine the magnitude of baseline emissions from the site and to
177
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verify If any adverse health or safety risks are present; and 2) survey the
...site using a portable analyzer and windscreen to delineate any localized
emission "hot spots." The results of these screening studies would need to be
Interpreted to determine 1f any further undisturbed emission measurements were
warranted.
5.4 CASE STUDY 4; WESTERN PROCESSING LANDFILL
Case Study 4 1s a former Industrial waste processing and recycling
facility.
5.4.1 Site History
*
The 13-acre Western Processing site Is situated In the Green River Valley
between Seattle and Tacoma, five miles Inland from Puget Sound. The site was
used for agricultural purposes until 1951 when 1t was leased to the Department
of Defense. An anti-aircraft artillery base operated there until the lease
expired in 1960. The owner opted for a cash settlement and left in place the
Installation's buildings and on-site drainage system that linked Its
facilities to a septic tank, a tile subsurface drain field, a 500-gallon
chlorlnation tank and a ditch leading to Mill Creek which runs along the
site's western border.
Western Processing, a waste recycling operation, purchased the site in
1960 and claimed to have reclaimed or recycled millions of gallons of liquid
waste and thousands of tons of solid waste before it was shut down in 1982.
f The wastes handled Included: animal blood, brewer's yeast, chrome baths,
corrosive liquids, crank case oil, flue dust, lead, pickle liquor, plating
bath solutions, solvents and paints, and zinc skimmings. These wastes were
handled, stored, or disposed of in storage lagoons (acid/caustic/cyanide
wastes), a fertilizer plant, a solvent recovery plant, bulk storage tanks,
cooling water lagoons, a chlorine gas tank storage house, a laboratory,
naphtha storage tanks, a SB-gallon drum storage area, and piles of flue dust.
By the late 1970s, the below-ground surface Impoundments had been filled and
were being used to store waste material.
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The site Is located In an Industrial area. A barbed wire fence separates
the site from a bicycle and jogging trail, which follows a railroad right-of-
way. This Is the nearest community exposure to the site. Trail users
reported seeing hoses draped over the fence discharging Into a ditch along the
railroad tracks that feeds Into Hill Creek, prior to the closure of the
:- recycling plant (61). The site 1s shown 1n Figure 26.
5.4.2 Objectives
The Remedial Investigation/Feasibility Study (RI/FS) process did not
address the air pathway for contaminant transport to any meaningful extent.
Therefore, no objectives were set or met.
5.4.3 Overview of Fleldwork for Site Characterization
v- State and local Inspections of Western Processing or Its vicinity date
i*back to 1977. These were Initially concerned about the quality of water *fn
5Mill Creek. In 1982, EPA determined that the company's management practices
, were resulting 1n the release of priority pollutants and other contaminants to
the environment.
A remedial investigation Initiated in the fall of 1982 led to emergency
and Interim remedial site activities In April 1983. These Included removal of
some liquids, solids, and drums, and reorganization of concrete blocks from
five surface Impoundments to create a large diked area where excavated
materials were then placed. The excavated materials contained solvents, paint
sludge, and some heavy metals. Also, buried storage tanks and drums were
encountered during this activity. Later in the fall, the state of Washington
led an effort to prevent storm water infiltration and runoff, which Included
further excavation and berming as well as paving of the reaction pond.
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RADIAN
C«»0*TIOM
SANITARY
DRAIN FIELD
DISCHARGE LINE
WESTERN PROCESSING
/ =
I! :
III
RAILROAD
/ :
DITCH I
* I
1 'I
Figure 26. Western processing site.
180
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A Phase I surface cleanup, funded by the potentially responsible parties,
started with release of a remedial action plan (62) In July 1984. In that
plan, 1t was clear that air emissions work had been United. The report noted
the northerly direction of winds would primarily deposit any contaminants
stirred up or blown off waste piles In or near Puget Sound. The report cited
a 1982 air analysis that showed only trace amounts of trlchloroethene,
.toluene, xylene, and tetrachloroethene. The low levels and high volatility of
these compounds, coupled with wide atmospheric dispersal, were thought to
create only limited effects on receptors during past operations. "Although
past releases Into the atmosphere may have been greater than observed 1n the
1982 samples and undoubtedly Included partlculate matter and contaminants.
Other than volatile organics, this pathway 1s not believed to have been
significant."
That the air pathway was overlooked to some extent during the RI/FS stage
Is apparent. However, Phase II remediation work began in 1987 to remove
shallow wastes at the site, and a comprehensive air monitoring program was
^initiated. This program Is outlined below (as described in Lepic and Foster
(63).)
An air monitoring program was Implemented to ensure adequate protection of
both the field team and the surrounding community. Work area monitoring was
conducted to identify action levels where personnel protection levels must be
upgraded. Continuous upwind and downwind perimeter monitoring was conducted.
Direct reading, real-time Instruments were used to determine total gases
and vapors, cyanide, gamma radiation and combustible gas; partlculate
concentrations also were measured. The field Instrumentation used at Western
Processing included:
OVA 128: total organic vapors;
HNU PI 101: .total organic vapors;
Hand-held aerosol monitor (HAM): total particulates;
Gastech CGI: combustible gases;
Ludlum 19: gamma radiation;
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Monltox Compur 4100: cyanide;
Draeger pump and colorimetrlc detector tubes: cyanide and methane;
H1-volume air samplers: suspended particulates; and
Recording meteorological station: wind direction and speed.
A1r was monitored regularly at 16 fixed locations around the site perimeter
to detect any possible off-site migration of airborne contaminants. In
addition, monitoring was conducted at each sample location to determine
adequate protection levels and to ensure worker safety. These monitoring
procedures are described below:
Borehole and excavation site monitoring: an OVA, HNU and HAM were used
to monitor the breathing zone at the drill rig and backhoe during the
subsurface exploration and sampling activities. A cyanide detector
and combustible gas Indicator were used regularly; and
Drum, tank and utility monitoring: an OVA and HNU, radiation detector,
*v-
combustible gas Indicator and cyanide monitor were used to test the
atmosphere within containers for flammable vapors.
5.4.4 Scoping
Collection and review of the existing data were performed. Based on this
data review, no need for an air pathway analysis was perceived.
5.4.5 Undisturbed Emissions Survey
No screening or In-depth measurements were made to assess the undisturbed
emissions at the site. Table 22 lists some of the contamination found at the
site. Based on the very high concentrations of heavy metals (e.g., lead at
31,000 ppm) found 1n the surface soil, an evaluation of the entrained
participate matter from the site would have been advisable, and some screening
measurements were warranted.
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TABLE 22. MAXIMUM AND AVERAGE CONCENTRATIONS IN SOIL FOR SELECTED CONTAMINANTS
Contaminant
Chromium
Z1nc
Arsenic
Antimony
. Lead
Cyanide
Phenol
Aldrin
Dieldrln
PCB-1248
Hexachloroethane
Phenanthrene
Pyrene
"1 , 1 , 1-Trichloroethane
^Methyl ene Chloride
Toluene
Trlchloroethene
Maximum
Surface
5,300
81,000
38
98
31,000
15
19.0
0
0.145
3.30
5,090
20,000
16,000
0
0.130
0
0.037
Cone, (com)
Subsurface
7,600
40,500
102
130
141,000
179
65.0
2.86
3.34
19.6
*
1,80
62.4
11.0
174
49
394
580
Average*
Cone, (ppm)
594
2,580
3.28
8.59
5,450
11.2
1.65
0.006
0.007
0.341
0.0192
720
184
2.87
1.49
6.44
19.3
* Based on geometric averaging approach.
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5.4.6 Disturbed Emissions Survey
' >
No screening or in-depth measurements were made to assess the disturbed
emissions at the site. Based on the very high concentrations of organic
compounds 1n the subsoil, an evaluation of the emission potential would have
been advisable.
5.4.7 Development of BEEs
No baseline emission estimates for either the undisturbed "or disturbed
wastes were generated. Given the available data, the best method for
determining BEEs for this site would be to take the existing ambient air
monitoring data (discussed below) and back-calculate an emission rate using an
fair dispersion model. This 1s done by setting up the model's run conditions
to match those at the site as closely as possible, and then varying the source
term to find an emission rate that produces downwind concentrations equal to
those actually measured. Using the respective air monitoring data sets, this M
procedure could be applied to both undisturbed and disturbed conditions.
5.4.8 Summary
The best technology for screening undisturbed particulate matter
^emissions at this site would have been to collect upwind/downwind samples on
filters using high-volume sampling pumps (hl-vols). The total particulate
matter present in the air would be determined by dividing the filter weight
gain by the volume of air sampled. Analysis of the filter catch for selected
fmetal species would assist in assessing the health Impacts from undisturbed
emissions. A less acceptable alternative would have been to measure the
ambient particulate matter loadings using a portable particulate matter
analyzer.
Screening VOC emissions also would have been advisable, based on the
waste composition data. The best technology for screening undisturbed VOC ^
emissions at this site would have been to: 1) perform ambient air monitoring I
around the perimeter of the facility to determine the magnitude of baseline
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emissions from the site and to verify 1f any adverse health or safety risks
were present; and 2) survey the site using a portable analyzer and windscreen
to delineate any localized emission "hot spots." The results of these
screening studies would need to be Interpreted to determine 1f further
undisturbed emission measurements were warranted.
The best technology for assessing disturbed VOC emissions would have been
to expose representative areas of waste using a backhoe (or drill rig), and to
measure emission rates using the flux chamber technique. The best technology
for assessing partlculate matter emissions would have been to use hi-vol
samplers arrayed downwind (I.e., transect technique) to capture emissions
during site disturbances.
5.5 CASE STUDY 5: OUTBOARD MARINE CORP. LAGOON/LANDFILL
Case Study 5 1s a manufacturing site where harbor sediments and nearby
land are contaminated with PCBs.
5.5.1 Site History .
Outboard Marine Corp. (OMC) sits on the west shore of Lake Michigan, 37
miles north of Chicago and 10 miles south of the Wisconsin border. This
hazardous waste site evolved from an outboard motor manufacturer that used
PCBs in die cast machines from the early 1950s to the early 1970s.
Over the years, the facility discharge created three areas of contami-
nation (see Figure 27). The first is Waukegan Harbor, a 37-acre Irregularly
shaped harbor feeding Into Lake Michigan. The operation also led to
contamination of "North Ditch," a small tributary that drains surface water
runoff Into Lake Michigan. A nine-acre parking lot north of the plant was
Identified as another area of significant PCB contamination.
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RADIAN
EAST-WEST PORTION
OF NORTH DITCH
NORTH SHORE
SANITARY
DISTRICT
PARKING
LOT
AREA
OUTBOARD MARINE CORP.
JOHNSON OUTBOARDS DIV.
PLANT NO. 2
OMC CORPORATE
HEADQUARTERS
OFFICES
NEW
DIE
CAST
COMPLEX
JOHNSON OUTBOARDS
PLANT NO. 1
\
Figure 27. Hap of Case Study 5 site.
186
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Concerns about possible receptors of site contamination Included the
harbor's biological community and fish 1n Lake Michigan. The City of
Waukegan, population 67,653 1n 1980, Is nearby, but the harbor area 1s zoned
Industrial. The 15 businesses 1n the Immediate harbor area that employ about
3,500 people were the Immediate concern. Also, the local Port Harbor received
heavy recreational use and long-term plans Included development of the Upper
Harbor. Potentially, people 1n a variety of locations could be exposed to the
.contamination via direct contact, fish consumption or possible drinking water
contamination.
OMC purchased roughly 9 million pounds of PCBs from Monsanto Co. over a
20-year period beginning in the early 1950s. OMC used the PCBs as hydraulic
fluids 1n die casting machines and related equipment. This equipment leaked
routinely and the fluids ran from the plant floor Into floor drains that
discharged Into Waukegan Harbor and North Ditch. EPA estimated that as much
as 20 percent of the PCBs purchased could have been discharged.
It was not until 1975 that the Illinois Environmental Protection Agency
.(IEPA) discovered the high levels of PCBs in soils and harbor sediments near
CMC's plant. This discovery was triggered by a 1971 EPA study that showed PCB
concentrations in Lake Michigan fish. In 1976, the EPA began to regulate PCB
disposal. At that time, OMC began to sample Its outfalls and then sealed two
outfalls leading to North Ditch, pursuant to a joint Administrative
Enforcement Order by EPA and IEPA (64). OMC later declined to Immediately
remove sediments contaminated with PCBs, as demanded by EPA. When clean-up
negotiations among EPA, IEPA, and OMC failed, legal actions were filed. These
legal actions were still pending in early 1988. Superfund money for this site
became available in 1983.
5.5.2 Objectives
The objective of the APA for this site was to model the exposure of
downwind receptors to PCBs during baseline conditions.
187
-------
5.5.3 Scoping
Existing data were collected and reviewed to provide a working knowledge
of the site history, conditions, and environmental setting. No Information
was uncovered that Indicated a need to modify the air pathway analysis
objectives.
5.5.4 Overview of Fleldwork for Site Characterization
Discovery steps through site characterization led to the conclusion that
PCB concentrations were significant and that PCB release to the surrounding
environment could follow a number of pathways.
Waukegan Harbor--
EPA contractors estimated that 1n Slip Number 3 1n the harbor about 7,200
cubic yards of muck, varying in thickness from 2 to 5 feet, was contaminated
by about 167,200 pounds of PCBs. Concentrations typically exceeded 500 ppm.
Another 3,700 cubic yards of sand and silt (about 7 feet thick) were
contaminated by about 138,000 pounds of PCBs. In one localized area near a
former OMC outfall, concentrations exceeded 10,000 ppm.
In the upper harbor about 35,700 :ub1c yards of muck, 1 to 5 feet thick,
were contaminated with approximately 5,000 pounds of PCBs. Concentrations
here typically were 50 to 500 ppm.
North Ditch- '
Contractors broke the North Ditch Into three areas for study. In the
"crescent ditch," about 28,900 cubic yards of soil, roughly 25 feet thick,
were contaminated by about 403,700 pounds of PCBs, creating concentrations
ranging from 5,000 to 38,000 ppm. Another 2,300 cubic yards of soil 3 feet
thick north of the die storage area were contaminated by an estimated 200
pounds of PCBs. Concentrations here typically were about 200 ppm.
188
-------
The "oval lagoon," about 27 feet deep, contained about 14,600 cubic yards
of soil contaminated by about 85,500 pounds of PCBs 1n the top 5 feet.
Concentrations within those 5 feet were about 26,000 ppm; no data were
available for below 5 feet.
In the main part of North Ditch, about 25,000 cubic yards of soil about
25 feet thick were contaminated by at least 4,300 pounds of PCBs.
Concentrations In 200 feet of
-------
5.5.6 Disturbed Emissions Survey
No field measurements or modeling estimates were made to assess the
emissions during site disturbances. It would be advisable to conduct a
laboratory or field study to determine the degree to which volatilization will
Increase during dredging or other site remediation work. The emission
estimates could then be used as Inputs to dispersion models to assess the
Impact on downwind receptors.
5.5.7 Development of BEEs
As discussed above, undisturbed (baseline) emission estimates were
»
developed for two of the three operable units at the site. These estimates
were 12 to 40 Ib. PCB/year and 15 Ib. PCB/year. No disturbed emission
estimates were developed. If emission rate data were available for waste in
the disturbed state (e.g., flux chamber test data), then disturbed emission
estimates should have been developed using the same modeling approach used to
develop the BEEs.
5.5.8 Summary
The air pathway for contaminant transport was assessed at this site for
undisturbed conditions using modeling techniques. This was a valid, cost-
effective option, given the logistical problems of making direct field
measurements at this site and the low probability of detecting PCBs in the
ambient air downwind of the site.
The best technology for assessing the disturbed PCB emissions would have
been to dredge up representative contaminated material and directly measure
emissions with a flux chamber. As an alternative, this approach could be
modified to perform the work in a laboratory setting.
190
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SECTION 6
REFERENCES
1. NUS Corporation. Procedures for Conducting A1r Pathway Analyses for
Superfund Applications - Volume 1, Application of A1r Pathway Analyses
for Superfund Activities. EPA Draft Manual, December 1988.
2. Radian Corporation. Estimation of Air Emissions From Clean-up Activities
at Superfund Sites. EPA Interim Final Manual, January 1989.
3. NUS Corporation. Procedures for Conducting A1r Pathway Analyses for
Superfund Applications - Volume IV, Procedures for Dispersion Modeling
and Air Monitoring for Superfund Air Pathway Analysis. EPA Draft Manual,
December 1988.
4. Camp, Dresser and McKee, Inc. Guidance Document for Cleanup of Surface
. Impoundment Sites. Prepared for U.S. Environmental Protection Agency,
June 1985.
5. Hwang, S.T. Model Prediction of Volatile Emissions. Environmental
Progress, Vol. 4, No. 2, May 1985.
6. Shen, T.T. Air Pollution Assessment of Toxic Emissions from Hazardous
Waste Lagoons and Landfills. Environmental International, Vol. II, pp.
71-76, 1985.
7. Shen, T.T. Air Quality Assessment for Land Disposal of Industrial
Wastes. Environmental Management, Vol. 6, No. 4, pp. 297-305, 1982.
8. Shen, T.T. Estimating Air Emissions from Disposal Sites. Pollution
Engineering, 13(8), pp. 31-34, 1981.
9. Shen, T.T. and G.H. Sewell. Air Pollution Problems of Uncontrolled
Hazardous Waste Sites. Civil Engineering for Practicing and Design
Engineers, 3(3):241-252, 1984.
191
-------
10. Balfour, W.D. and C.E. Schmidt. Sampling Approaches for Measuring
Emission Rates from Hazardous Haste Disposal Facilities. Presented at
the 77th Annual APCA Meeting, June 1984.
11. Storm, O.L. Hazardous Materials Common to Specific Industries. In:
Handbook of Industrial Waste Compositions in California. Cal. DHS 1978.
12. Radian Corporation. Air Quality Engineering Manual for Hazardous Waste
Site Mitigation Activities, Revision 2. Air Quality Engineering and
Technology, Department of Environmental Protection, Division of
Environmental Quality CN027, 1987.
*
13. CDM Federal Programs Corp. Data Quality Objectives for Remedial Response
ctiviteis. EPA 540/G-87-004, U.S. Environmental Protection Agency,
Washington, DC, 1987.
14. U.S. Environmental Protection Agency. Interim Guidellens and
Specifications for Preparing Quality Assurance Project Plans. QAMS-
005/08. Office of Monitoring Systems and Quality Assurance, Office of
Research and Development, Washington, DC, 1980.
15. KapUn, E.J., A.J. Kurtz, and M. Rahlmi. VOC Sampling for Emission Rate
Determination and Ambient Air Quality on an Inactive Landfill. Presented
at New England Section, Air Pollution Control Association, Fall 1986
Conference, Worcester, MA, October 6-7, 1986. 27 pp.
16. South Coast Air Quality Managmente District. Landfill Gas Emissions:
Report of the Task Force, El Monte, CA, 1982.
17. Wood, J.A., and M.L. Porter. Hazardous Pollutants in Class II Landfills.
South Coast Air Quality Management District, El Monte, CA, 1986.
192
-------
18. Eklund, B.H., U.D. Balfour, and C.E. Schmidt. Measurement of Fugitive
Volatile Organic Emission Rates. Environmental Progress, 4(3):199-202,
1985.
19. Balfour, H.D., B.M. Eklund, and S.J. Williamson. Measurement of Volatile
Organic Emissions from Subsurface Contaminants. Radian Corporation,
Austin, TX, 1985. 20 pp.
20. Dupont, R.R. Measurement of Volatile Hazardous Organic Emissions.
Journal of the A1r Pollution Control Association, 37(3):168-176, 1987.
21. Balfour, W.D., R.G. Wetherold, and D.L. Lewis. Evaluation of Air
Emissions from Hazardous Waste Treatment, Storage, and Dis'posal
Facilities. EPA 600/2-85/057, U.S. Environmental Protection Agency,
Cincinnati, OH, 1984. 2 vol.
22. Eklund, B.M., M.R. Kienbusch, D. Ranum, and T. Harrison. Development of
>. a Sampling Method for Measuring VOC Emissions from Surface Impoundments.
Radian Corporation, Austin, TX, no date. 7 pp.
23. Keinbusch, M.R. Measurement of Gaseous Emission Rates from Land Surfaces
using an Emission Flux Chamber: Users Guide, EPA Contract 68-02-3889,
Radian Corporation, Austin, TX, 1986.
24. Cowherd, C. Measurement of Particulate Emissions from Hazardous Waste
Disposal Sites. For presentation at: 78th Annual Meeting, A1r Pollution
Control Association, Detroit, MI, June 16-21, 1985.
" 25. Astle, A.D., R.A. Duffee, and A.R. Stankunas. Estimating Vapor and Odor
Emission Rates from Hazardous Waste Sites. In: National Conference on
Management of Uncontrolled Hazardous Waste Sites, U.S. Environmental
Protection Agency, et al., Washington, D.C., 1982. pp. 326-330.
26. Eklund, B. Detection of Hydrocarbons 1n Groundwater by Analysis of
Shallow Soil Gas/Vapor. Radian Corporation, Austin, TX, 1985. 78 pp.
193
-------
27. Devitt, D.A., R.B. Evans, U.A. Jury, T.H. Starks, B. Eklund, and A.
Gholson. Soil Gas Sensing for Detection and Mapping of Volatile
Organics. National Hater Hell Association. 1987.
28. Kerfoot, H.B. Soil-Gas Measurement for Detection of Groundwater
Contamination by Volatile Organic Compounds. Environmental Science and
Technology, 21(10):1022-1024, 1987.
29. Schmidt, C.E., R. Vandervort, and W.D. Balfour. Technical Approach and
Sampling Techniques Used to Detect and Map Subsurface Hydrocarbon
Contamination. For presentation at the 79th Annual Meeting, A1r
Pollution Control Association, Minneapolis, MN, 1986. 31 *pp.
30. Schmidt, C.E., and W.D. Balfour. Direct Gas Emission Measurement
Techniques and the Utilization of Emissions Data from Hazardous Waste
Sites. Reprinted from: National Conference on Environmental Engineering
Proceedings, Environmental Engineering Division, ASCE, 1983. 8 pp.
31. Balfour, W.D., C.E. Schmidt, and B.M. Eklund. Sampling Approaches for
the Measurement of Volatile Compounds at Hazardous Waste Sites. Journal
u/ Hazardous Material 14 (1987) 135-148.
32. EPA Reference Methods, Environment Reporter, December 5, 1980.
33. Radian Corporation. Review of Soil Gas Sampling Techniques. Austin, TX,
1983. 26 pp.
34. L.J. Thibodeaux, D.G. Parker, and H.H. Heck. Measurement of Volatile
Chemical Emissions from Wastewater Basins. U.S. EPA, Hazardous Waste
EngineerinResearch Laboratory, EPA/600/5-2-82/095. Cincinnati, OH 1982.
35. C.Cowherd, K.Axetell, C.M. Guenther, and G.A. Jutze. Development of
Emission Factors for Fugitive Dust Sources. EPA 450/3-74-037. U.S.
EPA, Cincinnati, OH 1974.
194
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36. Hetherold, R.G., and O.A. Oubose. A Review of Selected Theoretical
Models for Estimating and Describing Atmospheric Emissions from Waste
Disposal Operations. EPA Contract 68-03-3038, U.S. Environmental
Protection Agency, Office of Research and Development, Industrial
Environmental Research Laboratory, Cincinnati, OH, 1982. 73 pp.
37. EspUn, G.J. Boundary Layer Emission Monitoring. JAPCA Vol. 38, No. 9,
1158-1161 September 1988.
38. U.S. Environmental Protection Agency. Guideline on Air Quality Models
(Revised). Office of Air Quality Planning and Standards, PB86-245248.
Research Triangle Park, NC July 1986.
39. Baker, L.W., and K.P. MacKay. Screening Models for Estimating Toxic Air
Pollution Near a Hazardous Waste Landfill. Journal of the Air Pollution
Control Association, 35(11):1190-1195, 1985.
40. Farmer, W.J., M.S. Yang, J. Letey, W.F. Spencer, and M.H. Roulier. Land
Disposal of Hexachlorobenzene Wastes: Controlling Vapor Movement in
Soils. In: Land Disposal of Hazardous Wastes. Proceedings of the Fourth
Annual Research Symposium, U.S. Environmental Protection Agency,
Municipal Environmental Research Laboratory, San Antonio, TX, March 6, 7,
and 8, 1978. pp. 182-190.
41. Farmer, W.J., M.S. Yang, J. Letey, and W.F. Spencer. Land Disposal t)f
Hexachlorobenzene Wastes: Controlling Vapor Movement in Soil.
EPA-600/2-80-119, U.S. Environmental Protection Agency, Office of
Research and Development, Municipal Environmental Research Laboratory,
Cincinnati, OH, 1980. 69 pp.
42. U.S. Environmental Protection Agency. Hazardous Waste, Treatment,
Storage and Disposal Facilities (TSDF) Air Emission Models. Draft
Report, Office of Air Quality Planning and Standards, Research Triangle
Park, NC, 1987. pp. 6-1 to 6-16.
195
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43. Radian Corporation. Survey and Assessment of Air Emission Modeling
Techniques for Landfills. Draft Final Report. EPA Contract 68-01-7287,
U.S. Environmental Protection Agency, Washington, D.C., 1988. 115 pp.
44. Springer, C., K.T. Valsaraj, and L.J. Thlbodeaux. In Site Methods to
Control Emissions from Surface Impoundments and Landfills. Journal of
the Air Pollution COntrol Association, 36(12): 1371-1374, 1986.
45. Shen, T.T. Estimating Hazardous Air Emissions from Disposal Sites.
Pollution Engineering, 13(8):31-34, 1981.
46. Shen, T.T. Air Quality Assessment for Land Disposal of Industrial
;. Wastes. Environmental Management, 6(4):297-305, 1982.South Coast Air
Quality Management District. Landfill Gas Emissions: Report of the Task
Force, El Monte, CA, 1982.
47. Shen, T.T., and G.H. Sewell. Air Pollution Problems of Uncontrolled
Hazardous Waste Sites. Civil Engineering for Practicing and Design
Engineers, 3(3):241-252, 1984.
48. Farlno, W., P. Spawn, M. Oaslnski, and B. Murphy. Review of Landfill
AERR Models. In: Evaluation and Selection of Models for Estimating Air
Emissions from Hazardous Waste Treatment, Storage, and Disposal
Facilities. Revised Draft Ftnal Report. Contract No. 68-02-3168, U.S.
; Environmental Agency, Office of Solid Waste, Land Disposal Branch, 1983.
pp. 5-1 - 5-13.
49. Thlbodeaux, L.J., and S.T. Hwang. Landfarming of Petroleum Wastes -
Modeling the Air Emission Problem. Environmental Progress, l(l):42-46,
1982.
50. Shen, T.T. Air Pollution Assessment of Toxic Emissions from Hazardous
Waste Lagoons and Landfills. Environment International, ll(l):71-76,
1985.
196
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51. Hwang, S.T. Toxic Emissions from Land Disposal Facilities. Environmental
Progress, l(l):46-52, 1982.
52. DeWolf, G.B., and R.G. HethereId. Protocols for Calculating VOC
Emissions from Land Applications Using Emission Models. Radian
Corporation, Austin, TX, EPA Contract No. 68-02-3850, U.S. Environmental
Protection Agency, Research Triangle Park, NC, 1984. 28 pp.
53. U.S. EPA AP-42: Compilation of Air Pollutant Emission Factors, Fourth
Edition. USEPA/OAQPS RTP, NC September 1985.
54. Hwang, S.T. Estimating and Field-Validating Hazardous Air Emissions from
Land Disposal Facilities. In: Third Pacific Chemical Engineering
Conference, Seoul, Korea, 1983. pp. 338-343.
55. Thomas, R.G. Volatilization from Soil. In: Handbook of Chemical Property
Estimation Methods, U.J. Lyman, W.F. Reehl, and D.H. Rosenblatt, eds.
McGraw-Hill, New York, NY, 1982. pp. 16.1 - 16.50.
56. Mackay, D., and P.J. Leinonen. Rate of Evaporation of Low-Solubility
Contaminants from Water Bodies to Atmosphere. Environmental Science and
Technology, 9(13): 1178-1180, 1975.
57. Mackay, D., and A.T.K. Yeun. Mass Transfer Coefficient Correlations for
Volatilization of Organic Solutes from Water. Environmental Science and
Technology, 17(4):211-217, 1983.
58. Shen, T.T. Hazardous Air Emissions from Industrial Waste Treatment
Facilities. In: Industrial Waste: Proceedings of the Fourteenth
Mid-Atlantic Conference, June 27-29, 1982, J.E. Alleman and J.T.
Kavanagh, eds., Ann Arbor Science, Ann Arbor, MI, 1982. pp. 361-372.
59. Record of Decision, Remedial Alternative Selection, Bruin Lagoon Site,
Bruin Borough, PA. September 29, 1986.
197
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60. CH2M Hill. Phase I Remedial Investigation, Lowry Landfill, Vols. I and
II. EPA No 38.8LOS.3 Milwaukee, HI. September 2, 1986.
61. CH2MH111. Final Remedial Investigation Data Report: Western
Processing. RA-WA-37-OL16-1, Kent, HA. December 17, 1984.
62. Dames and Noore and Landau Associates Western Processing Technical Basis
for Remedial Action Plan, Phase II. October 3, 1984.
63. Leplc, K.A. and A.R. Foster. Superfund 1987: Proceedings of the Eighth
National Conference. Washington, DC. November 16-18, 1987.
64. U.S. Environmental Protection Agency. Superfund Record of Decision:
Outboard Marine Corp. Site, IL. EPA/ROD/R05-84/007, Washington, DC,
1984.
198
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APPENDIX A
ANNOTATED BILIOGRAPHY
-------
APPENDIX A
ANNOTATED BIBLIOGRAPHY
I. Adams, D.F. Sulfur Gas Emissions from Flue Gas Desulfurization
Sludge Ponds. Journal of the A1r Pollution Control Association,
29(9):963968, 1979.
This article describes an enclosure used to measure natural
sulfur species emissions. This article was used to assist In
the development of the Radian surface flux chamber.
II. Aim, R.R., C.P. Hanauska, K.A. Olson, and M.T. Pike. The Use of
Stabilized Aqueous Foams to Suppress Hazardous Vapors. -- A Study of
Factors Influencing Performance. In: Superfund '87: Proceedings of
the 8th National Conference, The Hazardous Materials Control
Research Institute, Washington, D.C., November 16-18, 1987. pp. 480-
484.
This article presents results from laboratory and field testing
of 3M vapor suppression foams. Field testing was performed on
excavated material using a direct emissions approach: surface
emissions Isolation flux chamber.
III. Aim, R.R., K.A. Olson, and R.C. Peterson. Using Foam to Maintain Air
Quality During Remediation of Hazardous Waste Sites. Presented at
the A1r Pollution Control Association's 80th Annual Meeting and
Exhibition, New York, NY, June 21-26, 1987. 17 pp.
This paper Is not useful for determining emission measurements
or estimating techniques. It also 1s not useful as a case
study. It provides some data on the effectiveness of foams
from laboratory tests and Radian testing of 3M foam, using a
surface isolation flux chamber.
IV. Aim, R.R., K.A. Olson, and E.A. Reiner. Stabilized Foam: A New
Technology for Vapor Suppression of Hazardous Materials. Presented
at the International Congress on Hazardous Materials Management,
Chattanooga, TN, June 8-12, 1987. 13 pp.
This paper is not useful for determining methods of emission
measurement or estimating, or as a case study. It provides
data on the effectiveness of vapor suppression foam from
laboratory tests using a "Radian-style" flux chamber and GC.
The paper includes few details and references Radian field
'testing of 3M foams.
-------
V. Asolan, M.F., and M.J. Barboza. A Practical Methodology for
Designing and Conducting Ambient A1r Monitoring at Hazardous Waste
Facilities. For Presentation at the 79th Annual Meeting of the Air
Pollution Control Association, Minneapolis, MN, 1986. 16 pp.
This paper presents an approach for designing ambient air
monitoring programs, including a decision tree. The emphasis
Is placed on establishing program objectives, Including why
sampling 1s performed, for who, and what 1s to be sampled. The
approach 1s Intended for use for project planning rather than
project execution.
VI. Astle, A.D., R.A. Ouffee, and A.R. Stankunas. Estimating Vapor and
Odor Emission Rates from Hazardous Waste Sites. In: National
Conference on Management of Uncontrolled Hazardous Waste Sites, U.S.
Environmental Protection Agency, et al., Washington, D.C., 1982.
pp. 326-330.
«
This article discusses sampling and evaluation of emissions for
odor. The sampling tunnel may have some usefulness for
investigating volatile emission rates versus wind speed;
however, the technique would require development and testing.
?VII. Baker, L.W., and K.P. tockay. Screening Models for Estimating Toxic
- Air Pollution Near a Hazardous Waste Landfill. Journal of the Air
Pollution Control Association, 35(11):1190-1195, 1985.
Baker and Mackay evaluate performance of four air dispersion
models to calculate the ambient air concentration of vinyl
chloride versus measured concentration downwind of a landfill.
The vinyl chloride emission rate was calculated using Shen's
modification of Farmer's gas migration equation. The air
dispersion models used are a ground level point source model,
two virtual point source mdoels, and a simple box model.
VIII. Balfour, W.D., R.G. Wetherold, and D.L. Lewis. Evaluation of Air
Emissions from Hazardous Waste Treatment, Storage, and Disposal
Facilities. EPA 600/2-85/057, U.S. Environmental Protection Agency,
Cincinnati, OH, 1984. 2 vol.
:' Emission rates based on direct and indirect emission
measurements were compared to emission rates calculated from
predictive models. Emission rate measurement techniques were
also compared against each other. Emission measurement
techniques include surface Isolation flux chamber, vent
sampling, concentration profile, transect, and mass balance.
Predictive models Include the Thibodeaux, Parker, and Heck
Models (non-aerated surface impound), the Thibodeaux-Hwang
Model (land treatment), and an API model (tanks). Details for
each measurement technique and model are provided.
-------
IX. Balfour, W.D., C.E. Schmidt, and B.M. Eklund. Sampling Approaches
for the Measurement of Volatile Compounds at Hazardous Waste Sites.
Radian Corporation, Austin, TX, no date. 29 pp.
Sampling techniques for measuring volatile emission rates and
for measuring soil gas concentrations are discussed. Emission
rate techniques Included are emission Isolation flux chamber,
vent sampling, concentration profile, transect, and mass
balance. Soil gas concentration techniques are headspace
analysis of soil cores, soil gas probes (ground probe), and
passive samplers.
Each approach Is described, and the applicable equations are
presented.
X. Balfour, W.D., and C.E. Schmidt. Sampling Approaches for Measuring
Emission Rates from Hazardous Waste Disposal Facilities. Radian
Corporation, Austin, TX, 1984. 13 pp.
Balfour and Schmidt present five sampling approaches for
measuring volatile emissions: surface emission Isolation flux
chamber, vent sampling, concentration-profile, transect
technique, and mass balance. A comparison of the applicability ^
of each technique to various TSDF sites or units 1s given. fl
XI. Balfour, W.D., B.M. Eklund, and S.J. Williamson. Measurement of
Volatile Organic Emissions from Subsurface Contaminants. Radian
Corporation, Austin, TX, 1985. 20 pp.
This paper presents results of field rcaasurement performed with
the surface emission Isolation flux chamber. It also evaluates
the effect of six operating variables on measured emission rate
and appropriateness of statistical sampling procedure for area
sources, and provides an analysis of variability 1n the method.
XII. Banerjee, P., and D.fl. Homer. The Impacts of Using Assumed Versus
Site-Specific Values 1n Determining Fate and Transport. In:
Superfund'87: Proceedings of the 8th National Conference, The
Hazardous Control Research Institute, Washington, D.C., November 16-
18, 1987. pp. 126-128.
This article does not discuss emission rate measurement;
rather, It emphasizes the Importance of the need to obtain
site-specific data rather then assumed or literature-derived
values as Inputs to risk assessment.
XIII. Berrafato, L.R., and R.A. Wadden. Predicted vs. Measured Air V
Emissions of Volatile Organlcs from a Simulated Hazardous Waste
Lagoon. In: Toxic Hazardous Wastes, Proceedings of the 18th Mid-
Atlantlc Hazardous Waste Conference, Chem. Ind. Inst. Toxicol.,
Research Triangle Park, NC, 1986. pp. 515-525.
-------
Evaporation of toluene and chlorobenzene from a simulated
lagoon was measured based on the liquid concentration of these
chemicals In the lagoon. The evaporation rate was compared to
a predictive model similar to the Mackay-Lelnonen Model. The
results showed the model may be useful for order of magnitude
estimates.
XIV. Bllsky, I.L. Air Pollution Aspects of Hazardous Waste Disposal In
Texas. Environmental Progress, 5(2):123-129, 1986.
This article examines the Texas administrative review process
for proposed hazardous waste disposal facilities. A case study
of a waste disposal facility application 1s reviewed.
XV. Blasko, M.J., B.F. Cockroft, W.C. Smith, and P.P. O'Hara. Design of
Remedial Measures and Waste Removal Program, Lackawanna Refuse
Superfund Site. In: Superfund '87: Proceedings of the 8th National
Conference, The Hazardous Control Research Institute, Washington,
D.C., November 16-18, 1987. pp. 367-370.
This article discusses the development of the design and con-
struction bid package for the remedial measures and removal
program. No Information on emissions data 1s given. The RI
report would have to be reviewed directly to see if a case
study exists.
XVI. Breton, M., T. Nunno, P. Spawn, W. Far1no, and R. Mclnnes.
Evaluation and Selection of Models for Estimating Air Emissions from
Hazardous Haste Treatment, Storage, and Disposal Facilities. EPA-
450/8-34-020, U.S. Environmental Protection Agency, Office of Air
Quality Planning and Standards, Emission Standards and Engineering
Division, Research Triangle Park, NC, 1984. 157 pp.
Mathematical models describing the release rate of volatile air
emissions from hazardous waste treatment, storage, and disposal
facilities were compiled and reviewed. Mathematical modeling
techniques which predict volatile air emission release rates
from landfills, landfarms, surface Impoundments, storage tanks,
wastewater treatment processes, and drum handling and storage
facilities were assessed. Existing field test validation
efforts were also reviewed. Models reviewed include: landfill
-- Farmer Model, Shen modification of Farmer Model, Thibodeaux
a Model, Thibodeaux Convective "Add On" Model, Thibodeaux b
Model, and Shen's Open Dump Model; land treatment --
Thlbodeaux-Hwang Model and Hartley Model; lagoons -- Mackay and
Leinonen Model, Mackay and Wolkoff Model, Thibodeaux, Parker
and Heck model, Shen Model, Smith Model, and McCord Model.
-------
XVII. Caputb, Jr., K., and R.L. Bittle. Case History: A Superfund
Cleanup 1n Central Pennsylvania. In: Hazardous and Toxic Wastes:
Technology, Management and Health Effects, S.K. Majumdar and E.W.
Miller, eds. Pennsylvania Academy of Science, Easton, PA, 1984.
pp. 228-241.
This chapter Is not relevant to the current project; no
emission measurements are reported. Caputo and Bittle describe
the general details of an emergency cleanup at an Industrial
site.
XVIII. Caravanos, J., and T.T. Shen. The Effect of Wind Speed on the
Emission Rates of Volatile .Chemicals from Open Hazardous Waste Dump
Sites. Source unknown.
This article presents a modified diffusion equation (Shen
Model), which Includes wind speed as a variable. Experimental
data are presented for benzene, carbon tetrachlorlde, and
trlchloroethylene applied to soil, which approximate a spill.
The equation also could be applied to waste exposed at surface.
XIX. Cassis, J.A., E.P. Kunce, and T.A. Pederson. Remedial Action at
Uncontrolled Hazardous Waste Sites: Problems and Solutions. In: M
Hazardous Waste Management for the 1980s, T.L. Sweeney, H.G. Bhatt, V
R.M. Sykes, and O.J. Sproul, eds. Ann Arbor Science, Ann Arbor, MI, ^
1982. pp.241-264.
This chapter Is not relevant to this program. The authors
describe a remedial action plan for the Pollution Abatement
Services Oswego Site in Oswego, New York.
XX. Cimorel!i, A.J. Palmerton Zinc National Priorities List Site:
Atmospheric Deposition Analysis of Cadmium, Zinc, Lead and Copper in
the Vicinity of the New Jersey Zinc Palmerton Facility. U.S.
Environmental Protection Agency Region III Air Management Division,
1986. 93 pp.
Cimorelli discusses heavy metal deposition from stack
emissions. Meteorological data are used to Identify areas of
high deposition, to design a soil sampling program.
XXI. Countess, R.J., R. Brewer, and R.J. Gordon. Sampling Airborne Toxic
Organics by Remote Control. Presented at the 78th Annual Meeting of
the Air Pollution Control Association, Detroit, MI, 1985. 16 pp.
This paper describes a radio-controlled air sampler, which
would be useful as a sampling method.
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XXII. Cowherd, C. Measurement of Particulate Emissions from Hazardous
Waste Disposal Sites. For presentation at: 78th Annual Meeting, Air
Pollution Control Association, Detroit, MI, June 16-21, 1985.
Article describes the MRI wind tunnel and exposure profiling
techniques for participate emissions rate measurement. The MRI
wind tunnel Is a portable wind tunnel which can be used for
direct emissions measurement. The exposure profiling technique
1s used for Indirect emissions measurement and Is similar to
the transect technique.
~XXIIi; Cox, R.D., K.J. Baughman, and R.F, Earp. A Generalized Screening
and Analysis Procedure for Organic Emissions from Hazardous Waste
Disposal Sites. In: Proceedings of the 3rd National Conference and
Exhibition on Management of Uncontrolled Waste Sites, Washington,
D.C., 1982.
The authors describe a technique developed by Radian
Corporation for analysis of gas, liquid, and solid
environmental samples. The technique uses gas chromatography
with flame ionization, photoionization and Hall electrolytic
conductivity detectors, as well as mass spectrometry.
*,XXIV. DeWolf, 6.B., and R.6. Wetherold. Protocols for Calculating VOC
j, Emissions from Surface Impoundments Using Emission Models:
Technical Note. Radian Corporation, Austin, TX, EPA Contract No.
68-02-3850, U.S. Environmental Protection Agency, Research Triangle
Park, NC, 1984. 34 pp.
DeWolf and Wethrrold present the Thibodeaux models for aerated
and nonaerated steady-state Impounds and the Mackay and
Lelnonen Model for unsteady-state Impounds. Input variables
are defined, sources of these variables are suggested, and
approximate precision levels for the variables are given.
Physical property Inputs are discussed and methods for their
estimation are given, along with selected values for some
materials.
XXV. DeWolf, G.B., and R.G. Wetherold. Protocols for Calculating VOC
- Emissions from Land Applications Using Emission Models. Radian
Corporation, Austin, TX, EPA Contract No. 68-02-3850, U.S.
Environmental Protection Agency, Research Triangle Park, NC, 1984.
28 pp.
The authors present the Thibodeaux-Hwang Model for land
treatment and the Farmer Model for landfills. Input variables
are defined, sources of the variables are suggested, and
approximate precision levels for the variables are given.
Physical property inputs are discussed and methods for their
estimation are given, along with selected values for some
materials.
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XXVI. Dupont, R.R. A Flux Chamber/Solid Sorbent Monitoring System for Use
1n Hazardous Organic Emission Measurements from Land Treatment
Facilities. Presented at the 79th Annual Meeting of the Air
Pollution Control Association, Minneapolis, MN, 1986. 15 pp.
This paper reports on testing of the emission Isolation flux
chamber with Tenax\ tubes as the sampling media.
XXVII. Dupont, R.R. A Flux Chamber/Sorbent Tube Monitoring System for
Hazardous Organic Emission Measurements from Land Treatment
Facilities. In: 192nd National Meeting, American Chemical Society,
Division of Environmental Chemistry, 26(2):394-397, 1986.
This 1s not useful for a case study; the technology 1s already
known. The article reports that testing of the emission Isola-
tion flux chamber with Tenax\ tubes for sample collection was
effective for measuring specific volatile species under both
laboratory and field conditions.
XXVIII. Dupont, R.R. Measurement of Volatile Hazardous Organic Emissions.
Journal of the A1r Pollution Control Association, 37(3):168-176,
1987.
An emissions Isolation flux chamber was laboratory tested In
combination with Tenax\ and charcoal tube sampling to determine
the recovery efficiencies for selected organics. The testing
validates the use of a "Radian-style" flux chamber. Testing
Included the use of flow rates significantly below the standard
protocol.
XXIX. Eklund, B.M., U.D. Balfour, and C.E. Schmidt. Measurement of
Fugitive Volatile Organic Emission Rates. Environmental Progress,
4(3):199202, 1985.
This article describes the design and operation of a "Radian-
style" emission Isolation flux chamber. It also provides
limited data from several projects, which can be used as
emission measurement case studies.
XXX. Eklund, B. Detection of Hydrocarbons in Groundwater by Analysis of
Shallow Soil Gas/Vapor. Radian Corporation, Austin, TX, 1985. 78
pp.
This report describes five methods of measuring soil vapor
concentrations: surface flux chamber, soil probe, downhole
flux chamber, accumulator, and soil coring. All five methods
would be useful for data collection for direct measurement
-and/or predictive modeling.
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XXXI. Eklund, B.M., W.D. Balfour, and C.E. Schmidt. Measurement of
Fugitive Volatile Organic Compound Emission Rates with an Emission
Isolation Flux Chamber. For presentation at: AIChE Summer National
Meeting, Philadelphia, PA, 1984. 8 pp.
The authors present the procedures for using the surface
emission Isolation flux chamber for direct emission rate
measurement. Also presented are the results of measurements at
two spill sites, three landfills, several surface Impounds, a
landfarm, and a remedial action.
XXXII. Eklund,,B.M., M.R. Klenbusch, D. Ranum, and T. Harrison.
Development of a Sampling Method for Measuring VOC Emissions from
Surface Impoundments. Radian Corporation, Austin, TX, no date. 7
pp.
This paper describes the development program for evaluating and
modifying the design and operation of the surface Isolation
flux chamber for use on surface Impounds.
XXXIII. Enfield, C.G., R.F. Carsel, S.Z. Cohen, T. Phan, and D.M. Walters.
Approximating Pollutant Transport to Ground Hater. Ground Water,
20(6): 711-722, 1982.
This article does not provide Information on emission rate
determination. It present three transport models for
evaluating the movement of organic chemicals through the soil
to the groundwater. The models Include losses due to
degradation and sorptlon. Field data are compared to the
models.
XXXIV. Engineering Science, Inc. Determination of Air Toxic Emissions from
Non-Traditional Sources In the Puget Sound Region. EPA 910/9-86-
148, U.S. Environmental Protection Agency, Region X and Puget Sound
Air Pollution Control Agency, Seattle, WA, 1986. 108 pp.
This report develops emission estimates for several selected
sources in the Puget Sound Region Including POTWs, Industrial
wastewater treatment plants, Superfund sites, municipal land-
fills, and TSDFs. Emissions are based on theoretical
equations. The report contains some useful examples of
theoretical equation applications. The report may also provide
case study site information.
XXXV. Farino, W., P. Spawn, M. Jasinski, and B. Murphy. Review of
Landfill AERR Models. In: Evaluation and Selection of Models for
Estimating Air Emissions from Hazardous Waste Treatment, Storage,
and Disposal Facilities. Revised Draft Final Report. Contract No.
68-02-3168, U.S. Environmental Agency, Office of Solid Waste, Land
Disposal Branch, 1983. pp. 5-1 - 5-13.
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This section describes six predictive models that estimate
volatile emissions: Fanner, Shen's modification of Fanner,
Thlbodeaux (three variations), and Shen's Open Dump. The first
five models are based primarily on gas diffusion through the
landfill cover.
XXXVI. Farmer, W.J., M.S. Yang, J. Letey, W.F. Spencer, and M.H. Rouller.
Land Disposal of Hexachlorobenzene Wastes: Controlling Vapor
Movement 1n Soils. In: Land Disposal of Hazardous Wastes.
Proceedings of the Fourth Annual Research Symposium, U.S.
Environmental Protection Agency, Municipal Environmental Research
Laboratory, San Antonio, TX, March 6, 7, and 8, 1978. pp. 182-190.
Farmer presents a predictive equation for determining
hexachlorobenzene vapor diffusion through a soil cover.
Volatilization through soil, water, and polyethylene film was
studied In laboratory simulations. The predictive equation
should be applicable to other waste types.
XXXVII. Farmer, W.J., M.S. Yang, J. Letey, and W.F. Spencer. Land Disposal
of Hexachlorobenzene Wastes: Controlling Vapor Movement 1n Soil.
EPA-600/280-119, U.S. Environmental Protection Agency, Office of
Research and Development, Municipal Environmental Research
Laboratory, Cincinnati, OH, 1980. 69 pp.
The volatilization fluxes of hexachlorobenzene through a
covering of soil, water, and polyethylene film were simulated
In the laboratory. Volatilization through soil was directly
related to soil porosity. Fanner develops a diffusion equation
for determining flux rates through the soil covering.
XXXVIII. Glllesple, D.P., F.J. Schauf, and J.J. Walsh. Remedial Actions at
Uncontrolled Hazardous Waste Sites, Survey and Case Study Investiga-
tion. In: Proceedings of the Second National Symposium on Aquifer
Restoration and Ground Water Monitoring, National Water Well
Association, Worthlngton, OH, 1982. pp. 369-374.
This paper 1s not useful. It discusses how nearly half of all
remedial actions completed by 1980 were Ineffective at cleaning
up the sites.
XXXIX. Gravltz, N. Derivation and Implementation of Air Criteria During
Hazardous Waste Site Cleanups. Journal of the A1r Pollution Control
Association, 35(7):753-758, 1985.
This article presents an approach for developing fenceline air
monitoring criteria to protect community health. The approach
?1s dependent on developing acceptable community exposure
levels, and back calculating the fenceline concentration by
assuming Gaussian wind dispersion. The method does not require
emissions measurement.
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XL. Greenberg, H. A Review of: 1) A Technical Approach for Sampling and
Analysis of VOCs at Hazardous Waste Sites and 2) Some Case Studies
In New Hampshire. Presented before the Fall Meeting, Air Pollution
Control Association New England Section, Conference on A1r Toxics,
Worcester, MA, October 6-7, 1986. 30 pp.
This document contains overhead slides for a conference
presentation on sampling VOCs in ambient air at landfills.
Case studies are not worked up as emission estimates.
XLI. Hanisch, R.C., and M.A. McDevitt. Protocols for Sampling and
Analysis of Surface Impoundments and Land Treatment/Disposal Sites
for VOCs. EPA Contract No. 68-02-3850, U.S. Environmental
Protection Agency, Office of Air Quality Planning and Standards,
Research Triangle Park, NC, 1984. 88 pp.
The report gives detailed description for analysis of volatile
organics by Radian gas chromatography with multiple detectors
(GC/MD) system and gas chromatography with mass spectrometry
(GS/MS) system. The report gives a brief discussion of predic-
tive emission models and lists Inputs to models, but does not
present models. A description of a statistical approach to
collecting sufficient samples for representativeness 1s
Included. - .
XLII. Helsing, L.D., M.P. Morningstar, J.B. Berkowitz, and T.T. Shen. Risk
Analysis of Pollutants at Hazardous Waste Sites: Integration Across
Media Is the Key. In: Superfund '87: Proceedings of the 8th
National Conference, The Hazardous Control Research Institute,
Washington, O.C., November 16-18, 1987. pp. 471-475.
This paper describes the types of pollutants frequently found
at hazardous waste sites and how they can be transferred from
one media to another. This paper describes how all media need
* to be taken Into account when performing risk analysis. No
Information on emission rate determination is provided.
XLIII. Hwang, S.T. Measuring Rates of Volatile Emissions from Non-Point
Source Hazardous Waste Facilities. Presented at the 75th Annual
Meeting of the Air Pollution Control Association, New Orleans, LA,
1982. 22 pp.
This paper presents Concentration Profile, Plume Mapping (tran-
sect), and Upwind/Downwind models for Indirectly measuring
emission rates.
XLIV. Hwang, S.T. Toxi^Emissions from Land Disposal Facilities. Environ-
mental Progress, rl(l):46-52, 1982.
-------
Hwang gives theoretical equations for emission rate estimates
from surface Impoundments (natural surface and aerated), land-
fills (based on soil diffusion), and land treatment (oily
wastes). The equations require knowledge of waste and site
characteristics to determine variables and coefficients. All
equations would be difficult to apply for a complex waste,
requiring computer calculation. The equations can be applied
more easily to a single component waste, or Its primary compo-
nents.
XLV. Hwang, S.T. Comparison of Model Predicted Volatile Emission Rates
Versus Results of Field Measurements at Hazardous Waste Sites.
Presented at: American Institute of.Chemical Engineers, National
Meeting, Summer 1984. American Institute of Chemical Engineers, New
York, NY. 18 pp.
Paper presents a comparison of measured and estimated emission
rates based on field sampling results and theoretical models.
Measurements were performed at landfills, surface Impounds, and
land treatment facilities. Field sampling techniques used were
concentration profile, transect, and surface emission Isolation
flux chamber. The predicted emission rates were generally
within the confidence Intervals of the measured emission rates,
although the author Indicates that more study 1s required to
validate the models. The specific models used are referenced
but not discussed.
XLVI. Hwang, S.T. Estimating and Field-Validating Hazardous Air Emissions
from Land Disposal Facilities. In: Third Pacific Chemical
Engineering Conference, Seoul, Korea, 1983. pp. 338-343.
Models for estimating volatile emissions are reviewed,
Including Shen's modification of Farmer's equation (landfill),
the Thlbodeaux-Hwang equation (land treatment) and surface
Impound equation. Predicted versus measured emissions
(concentration profile and upwind/downwind techniques) are
compared, but limited data are given.
XLVII. Hwang, S.T. Model Prediction of Volatile Emissions. Environmental
Progress 4(2):141-144, 1985.
Hwang presents a comparison of measured and predicted emission
rates. Measurement techniques Include transect and
concentration profile techniques. Isolation flux chambers and
upwind/downwind are also discussed. The article contains
limited data from potential case studies.
XLVIII. ICF,^Incorporated.. The RCRA Risk-Cost Analysis Model Phase III
Report Appendices. Submitted to the Office of Solid Waste, Economic
Analysis Branch, U.S. Environmental Protection Agency, 1982.
Appendix E, 31 pp.
-------
Appendix E describes natural chemical, physical, and biological
processes that reduce the concentration of chemicals 1n the
environment. These processes are the basis for deriving
surface and groundwater decay rates for the chemicals Included
1n the RCRA Risk-Cost Analysis Model. Important for baseline
emission rate estimates Is the discussion on volatilization
from water.
XLIX. Jubach, R.W., R.R. Stoner, T.F. laccarlno, and D.R. Smiley. An
Atmospheric Field Program Conducted at a Hazardous Waste Site.
1 Presented at the 78th Annual Meeting of the Air Pollution Control
Association, Detroit, MI, 1985. 14 pp.
This study characterizes the atmospheric dispersion at a
hazardous waste site from ground level release. The study
consists of releasing a tracer gas and measuring the concentra-
tion with two sampling arrays (I.e., transect techniques).
Measuring the of actual waste releases are not Included.
Downwind data could be useful as a theoretical case study.
L. Kaplin, E.J., A.J. Kurtz, and M. Rahimi. VOC Sampling for Emission
t. Rate Determination and Ambient A1r Quality on an Inactive Landfill.
» Presented at New England Section, Air Pollution Control Association,
Fall 1986 Conference, Worcester, MA, October 6-7, 1986. 27 pp.
This paper describes sampling performed at an Inactive landfill
in New York (a municipal waste landfill containing Industrial
waste). Sampling included ambient air, emission flux chamber
(crude), crevices, and vent, sampled with Tenax, PUF/GFF, mylar
bags, Impingers, and high volume samplers with GFF. Flux
measurements Included both covered and uncovered areas. Data
are somewhat limited, but this study may be useful as a case
study.
LI. Karably, L.S., and K.B. Babcock. Effects of Environmental Variables
on Soil Gas Surveys. In: Superfund '87: Proceedings of the 8th
National Conference, The Hazardous Control Research Institute,
Washington, D.C., November 16-18, 1987. pp. 97-100.
This may be useful as a case study if sufficient soil data are
available. Soil gas was measured at 40 locations and over time
at a fire fighting training area. This paper reports how
environmental conditions (principally weather) affected
results. Limited analytical data are presented.
LII. KaHml, A.A., W.J. Fanner, and M.M. Cliath. Vapor-phase Diffusion
of Benzene in Soil.-,-Journal of Environmental Quality, 16(l):38-43,
1987.
-------
The authors use Farmer's diffusion model and laboratory testing
method to determine benzene emission rates through soil (I.e.,
landfill emissions). The effects of soil bulk density and
moisture content are Investigated.
LIII. Kelnbusch, N.R. Measurement of Gaseous Emission Rates from Land
Surfaces using an Emission Flux Chamber: Users Guide, EPA Contract
68-02-3889, Radian Corporation, Austin, TX, 1986.
This document Includes a detailed description for using the
emission Isolation flux chamber, Including design of sampling
program, QA/QC, data reduction, and examples.
LIV. Kerfoot, H.B. Soil-Gas Measurement for Detection of Groundwater
Contamination by Volatile Organic Compounds. Environmental Science
and Technology, 21(10):1022-1024, 1987.
*
This article describes sampling using a ground probe system for
soil gas. Soil gas data are correlated with groundwater data
showing good correlation. Soil gas data are correlated with
soil probe depth below ground surface, also showing good
correlation. Ground water was at shallow depth 1n this study
(3-4m). Data could be used as a case study If additional soil
characteristics data are available. .
LV. Kerfoot, H.B., and P.B. Durgln. Soil-Gas Surveying for Subsurface
Organic Contamination: Active and Passive Techniques. In: Superfund
'87: Proceedings of the 8th National Conference, The Hazardous
Control Research Institute, ^'shington, D.C., November 16-18, 1987.
pp. 523-524.
This article provides an overview of considerations 1n
designing a soil-gas survey. It does not provide Information
on sampling techniques for air pathway assessment.
LVI. Lepic, K.A., and A.R. Foster. Remediation at a Major Superfund
Site: Western Processing -- Kent, Washington. In: Superfund '87:
Proceedings of the 8th National Conference, The Hazardous Control
Research Institute, Washington, D.C., November 16-18, 1987. pp. 78-
84.
This article summarizes a remedial Investigation conducted at a
Western Processing site. Continuous upwind and downwind air
monitoring was conducted, as well as some location-specific
sampling. It may be useful as a case study. No data on air
monitoring are presented; the author would have to be
contacted.
-------
L
LVII. Lewis* R.G., 8.E. Martin, D.L. Sgontz, and J.E. Howes. Measurement
of Fugitive Atmospheric Emissions of Polychlorlnated Blphenyls from
Hazardous Waste Landfills. Environmental Science and Technology,
19(10):986-991, 1985.
This article describes air sampling for PCBs at three
uncontrolled landfills and one controlled landfill. Emission
rates were not calculated. The data set may be usable for
calculating emission rates. Sampling was performed using low-
volume and high-volume samplers and PUF cartridges.
LVIII. Mackay, D.M., P.V. Roberts, and J.A. Cherry. Transport of Organic
Contaminants 1n Groundwater. Environmental Science and Technology,
19(5): 384-392, 1986.
This article describes the mechanisms Involved in the transport
of organic chemical contaminants in ground water, Including
advection, dispersion, sorption and transformation.
LIX. Mackay, D., and P.O. Lelnonen. Rate of Evaporation of Low-
Solubility Contaminants from Water Bodies to Atmosphere.
Environmental Science and Technology, 9(13): 1178-1180, 1975.
The authors present predict models (Mackay and Lelnonen) for
emission rates from aqueous systems. Equations are presented
for both steady and unsteady state systems.
LX. Mackay, D., and A.T.K. Yeun. Mass Transfer Coefficient Correlations
for Volatilization of Organic Solutes from Water. Environmental
Science and Technology, i7(4):211-217, 1983.
Volatilization rates of organic compounds in water were
measured In a wind-wave tank for compounds of varying Henry's
Law Constants. The data yielded correlations for liquid and
vapro-phase transfer coefficients as a function of windspeed,
and showed that interactions did not occur when mixtures of
compounds volatilized simultaneously.
LXI. Marquardt, G.D. Toxic Air Quality Investigation at a Hazardous
Waste Site. In: Superfund '87: Proceedings of the 8th National
Conference, The Hazardous Control Research Institute, Washington,
O.C., November 16-18, 1987. pp. 284-295.
This article does not provide data for baseline conditions.
However, It may be useful as a case study. Sampling was per-
formed upwind, on site, and downwind during field Investigation
(drilling) and during a controlled release from a gas well.
Sampling techniques could be used for Indirect measurement of
baseline emissions; techniques Include Tenax\, carbon molecular
sieve, high-volume participate sampler, and PUF.
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LXII. Meegoda, N.J., and P. Ratnaweera. A New Method to Characterize
Contaminated Soils. In: Superfund '87: Proceedings of the 8th
National Conference, The Hazardous Control Research Institute,
Washington, D.C., November 16-18, 1987. pp. 385-389.
This paper 1s not related to emission rate determination; it
presents an electrical method to determine engineering
characteristics of soil.
LXIII. Miller, G.C., V.R. Herbert, and R.G. Zepp. Chemistry and
Photochemistry of Low-Volatility Organic Chemicals on Environmental
Surfaces. Environmental Science and Technology, 21 (12):1164-1167,
1987.
This article discusses factors affecting the transformation,
mobility, and fate of xenobiotic chemicals (specifically
dioxins and PAHs). Emphasis is placed on discussing effects on
and near the soil surface and factors that affect the rate of
photolysis.
LXIV. Panaro, J.M. A1r Monitoring and Data Interpretation During Remedial
Action at a Hazardous Waste Site. In: Hazardous Wastes and
. - Environmental.Emergencies: Management, Prevention, Cleanup, Control,
Hazardous Materials Control Research Institute, Houston, TX, 1984.
pp.160-164.
Panaro describes the air monitoring program employed during
Initial remedial measures at a chemical recycling plant. He
does not address emission estimates.
IXV. Polcyn, A.J., and H.E. Hesketh. A Review of Current Sampling and
Analytical Methods for Assessing Toxic and Hazardous Organic
Emissions from Stationary Sources. Journal of the A1r Pollution
Control Association, 35(1):54-60, 1985.
v This article is a brief review of sampling methods (i.e.,
sample collection media) and analytical methods. The methods
are summarized in tables, and give references for detailed
descriptions. The article does not discuss measurement
techniques (i.e., sampling design) or modeling.
LXVI. Qulmby, J.M., R.W. Cibulskis, and M. Gruenfeld. Evaluation and Use
of a Portable Gas Chromatograph for Monitoring Hazardous Waste
Sites. Source unknown.
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This paper evaluates the use of the Century Systems Organic
Vapor Analyzer Model OVA-128 which Is a portable gas
chromatograph with a fume 1on1zat1on detector (GC-FID). The
paper addresses Instrument operating performance, QA/QC
consideration, operational difficulties and recommended field
uses. Instruments can be used to perform field screening of
ambient air, as well as other uses.
LXVII. Radian Corporation. Review of Soil Gas Sampling Techniques.
Austin, TX, 1983. 26 pp.
"'- Report presents the results of a literature review to Identify
techniques applicable to soil gas sampling and measurement.
LXVIII. Radian Corporation. 3M Foam Evaluation for Vapor Mitigation:
Technical Memorandum. Sacramento, CA, 1986. 95 pp.
*
The effectiveness of temporary and stabilized foam for control-
ling VOC emissions from petroleum refinery waste was tested.
Testing was performed using the surface emission Isolation flux
chamber.
*, LXIX. Radian Corporation. vA1r'Qua*l1ty Engineering Manual for Hazardous
'' Waste Site Mitigation Activities, Revision No. 2. Sacramento, CA,
1987. 291 pp.
This guidance document provides general Information for
designing and reviewing air monitoring programs for hazardous
waste site remedial programs. An overview of New Jersey's
agency Involvement 1n the remedial process Is given. Sampling
and analysis methods are discussed 1n detail.
LXX. Radian Corporation. Ambient A1r Monitoring at Hazardous Waste and
Superfund Sites, Revision No. 2. Sacramento, CA, 1987. 389 pp.
This guidance document provides Information for reviewing air
quality engineering activities for hazardous waste site
remediation programs. It also provides an overview of the
phases of the hazardous site remediation process and the role
of New Jersey's agencies In the process. Descriptions are
given for types of waste sites, potential air contaminants, and
basic remedial processes.
LXXI. Radian Corporation. Survey and Assessment of Air Emission Modeling
Techniques for Landfills. Draft Final Report. EPA Contract 68-01-
7287, U.S. Environmental Protection Agency, Washington, D.C., 1988.
115 pp.
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Article reviews theoretical models for landfill air emissions
Including: Farmer Hodel, Shen Model, Thibodeaux a Model,
TMbodeaux Logrithmic Gradient Model, RTI Closed Landfill
Model, Thibodeaux Convectlve "Add On" Model, Thibodeaux b
Model, Thibodeaux Exact Model, Arnold's Open Landfill Model,
Shen's Open Landfill Model, and RTI Open Landfill Model.
LXXII. Saeger, M.L., and E.E. Rlckman, Jr. Final Report: Ambient A1r
Monitoring at Hazardous Waste Treatment, Storage, and Disposal
Facilities, Phase I. EPA Project Number 68-02-4326, U.S.
Environmental Protection Agency, Emissions Standards and Engineering
Division, Office of Air Quality Planning and Standards, Research
Triangle Park, NC, 1968.
The authors contacted several state and federal regulatory
agencies and treatment, storage and disposal facilities (TSDFs)
to determine the air monitoring requirements for TSDFs. Few of
the states contacted had established requirements, and there
was no consistency among states. The program was of a limited
scope and was intended to determine if a study should be
conducted to assess the feasibility of conducting air
monitoring programs at TSDFs.
LXXIII. , Schmidt,
-------
This article presents an RI/FS/RM case study where an air
pathways assessment was performed at a hazardous waste site.
Both baseline and disturbed site air emissions were measured
and reported.
LXXVI. Schmidt, C.E., and M.VI. Eltgroth. Off-Site Assessment of A1r
Emissions from Hazardous Waste Disposal Facilities. Reprinted from:
Management of Uncontrolled Hazardous Waste Sites, Hazardous
Materials Control Research Institute, Silver Spring, MD, 1983.14 pp.
Field data and modeling (Lugranglan model) were used to
estimate downwind air concentrations of contaminants using
measured disturbed site emissions data. Modeled data were
compared to measured data.
LXXVII. Schmidt, C.E., and W.O. Balfour. Direct Gas Emission*Measurement
Techniques and the Utilization of Emissions Data from Hazardous
Waste Sites. Reprinted from: National Conference on Environmental
Engineering Proceedings, Environmental Engineering Division, ASCE,
1983. 8 pp.
This article describes direct emissions measurement techniques
e and discusses "various applications of/these techniques to waste
r management. Techniques Included are surface and downhole
Isolation flux chambers, ground probes, and soil vapor
monitoring wells.
LXXVIII. Schmidt, C.E., R. Vandervort, and W.D. Balfour. Technical Approach
and Sampling Techniques Used to Detect and Map Subsurface
Hydrocarbon Contamination. For presentation at the 79th Annual
Meeting, Air Pollution Control Association, Minneapolis, MN, 1986.
31 pp.
This paper presents a case study where several direct air emis-
sions measurement techniques were used to detect emissions from
a gasoline plume on groundwater about 90 feet below the land
surface.
LXXIX. Shen, T.T., and T. J. Tofflemire. Air Pollution Aspects of Land
Disposal of Toxic Waste. In: National Conference on Hazardous
Material Risk Assessment, Disposal and Management, Miami Beach, FL,
April 25-27, 1979. pp. 153-159.
This paper provides a general discussion of the air pollution
dangers Inherent 1n landfill Ing Industrial waste, especially
co-disposal with municipal waste. Volatilization processes are
discussed. Also discussed are methods for reducing the rate of
volatile loss.
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LXXX. Shen, T.T. Estimating Hazardous Air Emissions from Disposal Sites.
Pollution Engineering, 13(8):31-34, 1981.
This article presents Shen's modification of Fanner's equation
for the diffusion of volatlles from a landfill, and Zlegler's
modification of Arnold's equation for open dumps (also referred
to as Shen's open dump equation). A table of diffusion
coefficients for selected compounds 1s given. Two example
calculations for PCB emission are also given.
LXXXI. Shen, T.T., and G.H. Sewell. Air Pollution Problems of Uncontrolled
Hazardous Waste Sites. Civil Engineering for Practicing and Design
Engineers, 3(3):241-252, 1984.
Shen and Sewell provide three theoretical equations for
predicting emission rates (Shen landfill model, Shen landfarm
model, Shen lagoon model) for volatlles and one for dust. The
equations require some field data about soil, waste
characteristics, site size, etc., but no direct or Indirect
measurement of emissions. The equations should be used with
caution, and some spec1esspec1f1c coefficients may be difficult
to determine or Infer.
LXXXII. Shen, T.T. A1r Pollution Assessment of Toxic Emissions from ^
' Hazardous Waste Lagoons and Landfills. Environment International, V
11(1):71-76, 1985.
Shen briefly discusses the available methods for determining
emission rates and their drawbacks. He does not provide
technical detail for the use of methods, but Includes Isolation
flux chamber, transect, concentration profile, and predictive
models.
LXXXIII. Shen, T.T. Air Quality Assessment for Land Disposal of Industrial
Wastes. Environmental Management, 6(4):297-305, 1982.
Shen presents a models for predicting emission rates from land-
fills (Shen modification of Fanner), dumps (Arnold Model) and
lagoons based on the diffusion theory. Shen also presents data
on the comparison of predicted versus measured ambient concen-
tration of PCBs at a New York landfill. This article may be
useful as a case study.
LXXXIV. Shen, T.T. Hazardous Air Emissions from Industrial Waste Treatment
Facilities. In: Industrial Waste: Proceedings of the Fourteenth
Mid-Atlantic Conference, June 27-29, 1982, J.E. Alleman and J.T. *
Kavanagh, eds., Ann Arbor Science, Ann Arbor, MI, 1982. pp. 361- fl
372.
Shen presents predictive models for dust and volatile organics
emissions from lagoons (Shen Model), and discusses the fate of
volatile emissions in the environment in general terms.
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LXXXV. Sherman, S., W. Dickens, and H. Cole. Analysis Methods and Quality
Assurance Documentation of Certain Volatile Organic Compounds at
Lower. Detection Limits. In: Superfund '87: Proceedings of the 8th
National Conference, The Hazardous Control Research Institute,
Washington, D.C., November 16-18, 1987. pp. 280-283.
This paper Is not useful. It discusses modification of EPA
Method 624 to allow lower detection limits for groundwater
analysis.
LXXXVI. Sklpa, K.J., D.F. Ellas, and J.D. Gram. Monitoring and Evaluating
Multiple Source Emissions at Hazardous Waste Sites. Presented at
the 78th Annual Meeting of the Air Pollution Control Association,
Detroit, MI, 1985. 11 pp.
This paper discusses, in a generic form, the 1ss*ues to be con-
sidered In selecting monitoring and modeling approaches to
assess the air Impacts from a hazardous waste site.
LXXXVII. Smith, P.G., and S.L. Jensen. Assessing the Validity of Field
Screening of Soil Samples for Preliminary Determination of
Hydrocarbon Contamination. In: Superfund '87: Proceedings of the
8th National Conference, The Hazardous Control Research Institute,
Washington, D.C., November 16-18, 1987. pp. 101-103.
This paper compares results from vapor screening of samples in
the field using portable analyzers (FID and PID) to results
from laboratory TPH analyses. Comparison of the results showed
poor correlation Indicating the field screening of vapors
should not be used as the sole criteria for selecting samples
for analysis.
LXXXVIII. South Coast Air Quality Management District. Landfill Gas
Emissions: Report of the Task Force, El Monte, CA, 1982.
This report describes task force activities, Including sampling
of emissions at several landfills in the South Coast Air
Quality Management District. Data presented are very limited;
sampling methods were headspace over landfill, shallow ground
probe, and vent sampling. Site-specific sampling results could
possibly be worked up as a case study.
LXXXIX. Springer, C., K.T. Valsaraj, and L.J. Thibodeaux. In Situ Methods
to Control Emissions from Surface Impoundments and Landfills.
Journal of the Air Pollution Control Association, 36(12):1371-1374,
1986.
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This article discusses various control measures to reduce air
emissions from landfills and lagoons. Included are air-
supported structures, floating objects, shape modification,
aerodynamic redesign, oil and surfactant covers, and synthetic
membrane covers. The effectiveness and other considerations
for use of each method are discussed in general.
XC. St. Clalr, A.E., and K.T. Ajmera. Remedial Action at Uncontrolled
Hazardous Waste Sites. Environmental Progress, 3(3):188-193, 1984.
This paper describes the feasibility study approach used to
develop and select a cost-effective remedial action alternative
for the McColl Superfund site In Fullerton, California. Data
from the McColl remedial investigation, not presented in this
paper, can be used as a case study of baseline emission rate
determination.
XCI. Thibodeaux, L.J., and S.T. Hwang. Landfarming of Petroleum Wastes -
- Modeling the Air Emission Problem. Environmental Progress,
l(l):42-46, 1982.
This article reviews volatilization from land farming of
petroleum wastes, discusses distribution of oil waste in the ^
soil, and presents a gradlentless diffusion model for . M
estimating emissions (Thibodeaux-Hwang Model). The article ^
also gives predicted versus measured emission rates for
Deldrln.
XCI I. Thomas, R.G. Volatilization from Soil. In: Handbook of Chemical
Property Estimation Methods, W.J. Lyman, W.F. Reehl, and D.H. Rosen-
blatt, eds. McGraw-Hill, New York, NY, 1982. pp. 16.1 - 16.50.
This chapter presents a discussion of the theory of volatiliza-
tion of organics from soil. Thomas presents five models for
calculating volatile loss from the soil. The models are:
Hartley Model; Hamaker Model; Meyer, Letey, and Farmer Model;
Jury, Grover, Spencer, and Farmer Model; and Dow Methods. This
work is based on pesticides applied to soil. A decision tree
indicating which models apply for varying conditions is
Included. The models could be applied to sites with known
contaminants.
XCIII. Thomas, R.G. Volatilization from Water. In: Handbook of Chemical
Property Estimation Methods: Environmental Behavior of Organic Com-
pounds, W.O. Lyman, W.F. Reehl, and D.H. Rosenblatt, eds., McGraw-
Hill, New York, NY, 1982. pp. 15-1 to 15-34. A
Chapter describes the volatilization process from water. ^
Various methods for estimating volatilization rates are
discussed. The Mackay and Leinonen model and others are
presented.
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XCIV. Thome!oe, S. Summary of Reports Prepared for the Development of
Air Emission Standards for Hazardous Waste Treatment, Storage, and
Disposal Facilities. U.S. Environmental Protection Agency, Office of
A1r Quality Planning and Standards, Emission Standards and
Engineering Division, Chemicals and Petroleum Branch, Research
Triangle Park, NC, 1987.
This report contains annotated bibliographies and contacts for
several studies and reports. Most are directly applicable to
treatment, storage, and disposal facilities, but some may
provide sampling techniques applicable to uncontrolled sites.
XCV. Tucker, W.A., and L.H. Nelken. Diffusion Coefficients 1n Air and
Water. In: Handbook of Chemical Property Estimation Methods:
Environmental Behavior of Organic Compounds, W.J. Lyman, W.F. Reehl,
and D.H. Rosenblatt, eds. McGraw-Hill, NY, 1982. pp.-17-1 to 17-25.
Chapter discusses molecular diffusion 1n air and water.
Methods are not useful for estimating dispersion in air.
Methods may be relevant to uncontrolled sites (i.e., within
lagoon or landfill), however, factors such as wind mixing
(lagoons) or soil gas flow (landfills) may outweigh molecular
diffusion.
XCVI. U.S. Environmental Protection Agency. Letter from J.R. Farmer,
Director, Emission Standards and Engineering Division, to D. Kolar,
Environmental Counsel, Browning Ferris Industries, dated October 30,
1987, regarding EPA's Investigation of techniques for controlling
air emissions from municipal landfill facilities.
The U.S. EPA sent a questionnaire to Browning Ferris Industries
requesting Information on their landfills. The results, des-
cribed in this memorandum, do not provide Information for base-
line emissions.
XCVII. U.S. Environmental Protection Agency. Material on RCRA Facility
Investigation Guidance (RFI) provided by the U.S. Environmental
Protection Agency, Office of Air Quality Planning and Standards, to
Radian Corporation, Sacramento, CA, December 1987.
The material provided Includes a Section 12 on Air, Case Study
14: Use of Air Monitoring Data and Dispersion Modeling to
Determine Contaminant Concentrations Down-Wind of a Land
Disposal Facility, and Case Study 15: Use of Meteorological
Data to Design an Air Monitoring Network. This material
provides a recommended strategy for characterizing releases to
the air. .A1r monitoring and modeling are discussed in general
form. The Field Methods section provides considerable
Information on available sampling media and appropriate species
applications.
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XCVIII. U.S. Environmental Protection Agency. RCRA Facility Investigation
(RFI) Guidance, Volume III, Section 12, A1r and Surface Water
Releases. OSWER Directive 9502.00-6C, Office of Solid Waste, 1987.
Provide recommended strategy for characterizing releases to
air, which Includes characterizing the source and the
environmental setting for removal actions at RCRA facilities.
XCIX. U.S. Environmental Protection Agency. Superfund Exposure Assessment
Hanual. OSWER Directive 9285.5-1, Office of Solid Waste and
Emergency Response, Washington, D.C.
Section 2.3 of this manual presents eight equations for
predicting short-term and long-term emission rates for
landfills with and without Internal gas generation, lagoons,
landfarms, spills and leaks. Both participates-and volatile
emissions are discussed. Equations and discussions are given
for determining Input variables.
C. U.S. Environmental Protection Agency. Hazardous Waste Treatment,
Storage and Disposal Facilities (TSDF) --Air Emission Models. EPA-
450/3-87-026, Office of Air and Radiation, Office of Air Quality
Planning and Standards, Research Triangle Park, NC, 1987.
Analytical models are presented for estimating air emissions
from hazardous waste treatment, storage, and disposal
facilities (TSDF). Air emission models have been developed for
aerated and nonaerated surface Impoundments, land treatment
facilities, landfills, and wasteplles (RTI models). Emission
model predictions are compared to available field data. This
report also Includes emission factors for transfer, storage,
and handling operations at TSDFs. The models have been
assembled Into a spreadsheet that 1s Included In this report as
floppy diskette for use on a microcomputer. Appendices Include
a list of physical-chemical properties for approximately 700
compounds and a comprehensive source 11st of pertinent
literature In addition to that cited in the report.
CI. Vandervort, R., C.E. Schmidt, and W.D. Balfour. Surface and Subsur-
face Gas/Vapor Monitoring Techniques Applied to Environmental
Contamination Caused by Petroleum Products and Processing Wastes.
Radian Corporation, Sacramento, CA. 12 pp.
This paper discusses the application of surface and subsurface
emission rates and vapor concentration measurements for
Investigating petroleum leaks and hazardous waste site
; Investigations.
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CII. Vaught, C.C. A Basic Programming Technique for the Estimation of VOC
Emissions from Hazardous Waste Treatment, Storage, and Disposal
Facilities. Presented at the 78th Annual Meeting of the A1r
Pollution Control Association, Detroit, HI, June 16-21, 1985. 9 p.
This paper describes a BASIC program for use on microcomputer.
The program uses unspecified predictive models to estimate
emission rates for surface Impounds, landfills, land treatment,
and storage tanks. The program Includes a chemical library of
required model variables which are accessed by use of CAS num-
bers, as well as estimation programs for filling data gaps, and
adjustments for site- specific temperature conditions. The
. program was developed in 1985 and may have been updated.
CIII. Vogel, G.A. Air Emission Control at Hazardous Waste Management
Facilities. Journal of the Air Pollution Control Association, 35(5):
558-566, 1985.
This article 1s not related to emissions measurement. It
Identifies a method to control toxic air emissions from tanks,
lagoons, landfills, land treatment facilities, and waste piles.
Control cost information is also Included.
CIV. Walker, "K.A. Air Emissions from Hazardous Waste Treatment, Storage
and Disposal. Presented at the 77th Annual Meeting of the Air
Pollution Control Association, San Francisco, CA, 1984. 14 pp.
Summarizes OSW's work which is presented In detail by Balfour,
Wetherold, and Lewis (1984) included elsewhere is this biblio-
graphy. Volatile air emissions at TSDFs were compared for
measured versus predictive models.
CV. Weston, R.F. Performance of Remedial Response Activities at Uncon-
trolled Hazardous Waste Sites (REMII): Draft Remedial
Investigation/ Feasibility Study Report for the Bruin Lagoon Site,
Bruin Borough, Pennsylvania. U.S. EPA Contract No. 68-01-6939, U.S.
Environmental Protection Agency, 1986.
This report presents the results of the remedial investigation
performed at a refinery waste lagoon located 45 miles north of
Pittsburg in Bruin Borough, Butler County, Pennsylvania. Air
pathway analyses were performed for determining the health and
safety requirements for workers and nearby residences during
excavation of the lagoon. Also, sampling and analysis of sub-
surface soil gas from wells located in the lagoon were
performed to determine the soil gas composition, regeneration
rates, extent of trapped soil gas within the lagoon and to
assist in the assessment of the potential for the release of
soil gas into the atmosphere during future excavation.
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«
CVI. Wetherold, R.G., and D.A. Dubose. A Review of Selected Theoretical
Models for Estimating and Describing Atmospheric Emissions from
Waste Disposal Operations. EPA Contract 68-03-3038, U.S.
Environmental Protection Agency, Office of Research and Development,
Industrial Environmental Research Laboratory, Cincinnati, OH, 1982.
73 pp.
This report presents models for determining emissions from
landfills, land treatment, lagoons, waste piles, and tanks.
Models Include both predictive models and Indirect measurement
techniques. Estimates of model precision and accuracy, and
potential sources for model variables are Included. Models
Included are: Hartley Model; Thibodeaux-Hwang Model; Farmer
Model; Smith, Bomberger, Haynes Model, Mackay and Leinonen
Model; Thibodeaux Concentration Profile; and Thibodeaux,
Parker, and Heck Model.
CVII. Wetherold, R.G., B.M. Eklund, and T.P. Nelson. A Case Study of
Direct Control of Emissions from a Surface Impoundment. In:
Proceedings of the llth Annual Research Symposium on Incineration
and Treatment of Hazardous Waste, Annual Solid Waste Research
Symposium, U.S. Environmental Protection Agency, Cincinnati, OH,
1985. pp. 85-92.
Testing was performed to determine the effectiveness of an £
Inflated flexible dome enclosure in controlling VOC emissions ^j
from an aerated wastewater lagoon. Effectiveness was Investi-
gated by performing a mass balance of VOCs around the system.
The article Is not directly applicable to baseline emission
estimates.
Wood, J.A., and M.L. Porter. Hazardous Pollutants in Class II Land-
fills. South Coast Air Quality Management District, El Monte, CA,
1986.
This report describes sampling for air toxics at several Class
II landfills. Landfill gas sampling was performed at 20 sites
from vents (when present) and headspace over the site. Ambient
air sampling was performed at five sites. Air toxics were
detected even though the species cannot be legally disposed of
at Class II landfills.
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APPENDIX B
CHEMICAL AND PHYSICAL PROPERTIES
AFFECTING BASELINE EMISSION ESTIMATES
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CHEMICAL AND PHYSICAL PROPERTIES OF THE WASTE MATERIAL AFFECTING EMISSIONS
Property
Effect
Saturation Concentration
Diffusion Coefficient
Molecular Weight
Partial Pressure of
Constituents
Weight Fraction
Combination of Constituents
Concentration of Waste
Henry's Law Constant
The waste will tend to reach equilibrium with
the soil vapor. If sufficient waste 1s
present, the equilibrium concentration within
the air-filled voids of the soil matrix will
reach saturation. Because the rate of
emission to the atmosphere 1s directly
proportional tot he soil vapor concentration,
the emission rate will increase as saturation
concentration Increases.
Compounds with high overall diffusion
coefficients will be emitted at higher rates
than those with lower diffusion coefficients
via Increased transport, on a relative basis.
The overall diffusion coefficient may be
comprised of diffusion through the soil-water
Interface, soil-air Interface, soil, water,
air, and soil vapor.
Lower molecular weight compounds typically
have higher volatilization and diffusion
coefficients. Other compound characteristics
may predominate. Molecular weight is used to
determine diffusion rates in some predictive
models.
High partial pressure Increases the emission
rate of a species by increasing Its soil
vapor concentration.
An effect similar to partial pressure, it is
used as an input to some predictive models.
Not as Important as Henry's Law constant.
This increases the complexity of the
emissions process and determines the emission
rate. It may change over time as more
volatile species are lost.
Increasing waste concentration Increases the
emission rate for dilute wastes by Increasing
the vapor pressure and, therefore, vapor
concentration.
This is used to determine diffusion
coefficients. A high Henry's Law constant
produces a higher diffusion rate.
(Continued)
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Property
Porosity
Adsorption/Absorption
Properties of Soil
Soil Moisture
Wick Effect
Particle Size Distribution
Organic Content of Soil
Microbial Activity
Effect
One of the controlling factors for diffusion
through the soil. Emission rates typically
Increase with Increasing soil porosity.
Total porosity, I.e., dry soil, may represent
worst-case conditions for predictive models.
Air-filled porosity nay be more a realistic
parameter for many sites.
Soil with high sorptlon properties will
reduce the vapor density of the sorped
compounds and, therefore, the emission rate.
The effect may be minimal where high waste
concentrations saturate the sorption sites.
The effect may be reversed causing increased
emissions.
Its effect varies. High moisture will reduce
the air-filled porosity, with pores being
filled under worst-case conditions and,
therefore, should reduce the emission rate.
Moisture may be preferentially adsorped by
the soil, releasing volatiles and Increasing
the emission rate. Drying of soil may
Increase available sorptlon sites. Moisture
is required for the wick effect.
Soil moisture may draw waste constituents to
the surface through the soil pores. This
process can increase the concentration of the
constituents at the surface and, therefore,
Increase the emission rate.
This affects the total soil porosity and soil
pore continuity. Increased soil pore
continuity Increases the emission rate. A
higher percent of fines will typically
Increase particulate emissions.
High organic content will Increase the
sorptive characteristics of the soil and
reduce the emission rate. High organic
content also will increase microbial action.
Its effect varies. It may reduce the
emission rate by biological reduction of the
waste present. It also may increase the
emission rate due to gas formation which
carries volatile species to surface.
(Continued)
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Property
Effect
Depth of Landfill Cover
Compaction of Landfill'Cover
Ground Cover
Size of Landfill/Lagoon
Amount of Exposed Waste
Water Depth 1n Lagoon
Aeration of Lagoons
Temperature
Wind
Emission rates decrease with Increasing depth
(thickness) of cover as the diffusion path
Increases. For an open dump or landfill, the
cover thickness 1s zero.
Increasing compaction reduces the soil
porosity and disrupts continuity of the soil
pores, thereby, reducing the emission rate.
Soil cover, typically vegetation, will reduce
particulate emissions by reducing the
erodablHty of the soil. It also will help
hold soil moisture, which reduces the air-
filled porosity and reduces volatile
emissions.
The emission rate is directly proportional to
the size of the landfill or lagoon.
Emission will Increase when waste is exposed
at the surface, both due to volatilization
and wind erosion.
Water overlying waste will act as a cover.
Diffusion through water may control the
emission rate.
Aeration increases emission of volatile and
particulates with increasing volume of air
used and/or agitation. The effect 1s due to
air stripping of volatiles and bulk transport
of liquid particles.
Increasing temperature Increases the
volatilization rate for organic species and,
therefore, the emission rate. Increasing
temperature reduces soil moisture, increasing
air-filled porosity and the emission rate.
Wind removes the volatilized compound
concentration in the boundary layer over the
site, maintaining the driving force for
volatilization. Increasing wind speed
reduces the boundary layer over the site.
Wind causes turbulence within the boundary
layer, providing the driving force for
surface soil/waste erosion and increasing
particulate emission rate.
(Continued)
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Property Effect
Cloud Cover Increased cloud cover reduces solar heating
of the surface and, therefore, the
volatilization rate from surface. It also
affects wind stability.
Precipitation Emissions are reduced by reducing the air-
filled soil porosity. It may Increase
landfill emission by displacing soil vapor
from soil voids. It may Increase surface
water and air emissions by floating waste
constituents to the surface. Precipitation
Increases agitation of the lagoon surface,
potentially increasing emissions, but it also
increases water depth over waste in the
lagoon.
Humidity Increasing partial pressure of water vapor in
air reduces the capacity for some types of
volatilized material. It may reduce air-
filled soil porosity.
Barometric Pressure Changing barometric pressures cause bulk flow
of soil vapor into/out of soil. The overall
net effect is to Increase the emission rate.
The effect Increases with frequency and scale
of barometric changes.
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UPDATED AND/OR REVISED COPIES OF THIS VOLUME IN THE
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COMPLETE THE FOLLOWING AND MAIL TO:
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