United States
Environmental Protection
Agency
Technology Transfer
Office of Research and
Development
Washington, DC 20460
Office of Air Quality
Planning and Standards
Research Triangle Park NC 27711
EPA/625/R-92/003
August 1992
<>EPA Seminar Publication
Organic Air
Emissions from
Waste Management
Facilities
-------
-------
EPA/625/R-92/003
August 1992
Seminar Publication
Organic Air Emissions from Waste
Management Facilities
Center for Environmental Research Information
Office of Research and Development
Office of Air Quality Planning and Standards
U.S. Environmental Protection Agency
Cincinnati, Ohio 45268
Printed on Recycled Paper
-------
Disclaimer
The information in this document has been funded wholly by the United States
Environmental Protection Agency. It has been subject to the Agency's peer and adminis-
trative review, and it has been approved for publication as an EPA document Mention of
trade names or commercial products does not constitute endorsement or recommendation
for use.
-------
Contents
Page
Disclaimer . ii
Figures |v
Tables ,, vii
Acknowledgments ix
Introduction x
Workshop Schedule .....xj
Chapter 1 Air Pollution Overview 1
Chapter 2 Emission Sources and Controls 11
Chapter 3 Process Vents Standards—Subpart AA 27
Chapter 4 Equipment Leak Standards—Subpart BB 35
Chapter 5 RCRA Phase n Air Regulations 47
Chapter 6 RCRA Overview 51
Chapter 7 Implementation of RCRA Air Regulations 59
Chapter 8 Case Study: Measuring and Estimating Emissions 65
Chapter 9 Benzene Waste Operations NESHAP 75
Chapter 10 Case Study: Application of Benzene Waste Operations
NESHAP to Wastewater Treatment Systems 81
Chapter 11 Case Study: Process Vent Rule Applicability and Compliance 89
Chapter 12 Case Study: Equipment Leaks Testing—EPA Method 21 95
Appendices:
A Federal Register Excerpt—Revised Method 21 105
B Published Response Factors (From EPA 340/1-88-015) , 109
C Bibliography—Equipment Leak Monitoring 115
-------
Figures
Page
1-1. Ozone in the atmosphere
1-2. Tropospheric ozone formation
1-3. Photograph of lung from 19-year-old accident victim in Los Angeles
showing lung damage possibly due to ozone exposure
1-4. Areas exceeding the ozone NAAQS.
1-5. Sources of nationwide VOC emissions.
1-6. Top fourteen VOC/HAP chemicals...:
1-7. Hazardous waste management
1-8. Phases I and n RCRA air standards overlaid onto hazardous waste management.
1-9. Overlap of statutory coverage for air emission sources ,
1-10. Storage tanks under several "regulatory umbrellas."
2-1. Fate of organics: emissions, effluent, biodegradation, sludge. ,
2-2. Typical fixed-roof tank
2-3. Covered tanks (working losses)
2-4. Covered tanks (breathing losses).
2-5. External floating roof tank.
2-6. Emission sources for distillation ,
2-7. Emissions from solvent extraction
2-8. Individual drains
2-9. Typical junction box ,
2-10. Oil-water separator.
2-11. Schematic diagram of an air stripping system ,
2-12. Steam stripper for ethylene dichloride/vinyl chloride
2-13. Preliminary treatment prior to stripping ..,
2-14. Belt filter press
2-15. Flow path of thin-film evaporator ,
2-16. Splash loading vs. submerged loading
2-17. Land treatment emission mechanisms.
2-18. Emissions from a closed landfill
2-19. Carbon canisters ,
..1
,.2
...3
...3
...4
...5
...6
,...7
,...7
...8
.12
.13
.14
.14
,.14
.15
,.15
.16
.16
,.16
.17
,.17
,.17
.18
.18
.19
.20
.20
.21
IV
-------
Figures (continued)
2-20. Two-stage adsorption.system 21
2-21. Schematic diagram of a contact condenser 21
2-22. Schematic diagram of a shell-and-tube surface condenser 22
2-23. Packed tower for gas absorption 22
2-24. Steam-assisted elevated flare system. 23
2-25. Thermal incinerator 24
2-26. Catalytic oxidizer. 24
3-1 Example 1—air stripping 28
3-2. Example 2—steam stripping .'. 28
3-3. Number of units .29
3-4. Annual emissions from a typical facility 29
3-5. Facility bubble for emision rate (ER) 30
3-6. Example 3—control options for a facility 31
3-7. Example 3 (continued)—control options for a facility 31
3-8. Closed-vent system , ...32
3-9. Summary—applicability decision tree 32
4-1. Applicability 36
4-2. Centrifugal pump construction 37
4-3. Labyrinth shaft seal for compressors ....37
4-4. Rising stem gate valve 37
4-5. Spring-loaded relief valve 38
4-6. Leak area in flanged joint 38
4-7. Steam stripper 38
4-8. Sealless pumps can be designated for no detectable emissions 40
4-9. Schematic diagrams of two leakless pumps 41
4-10. Double mechanical seal with barrier fluid controls emissions ...42
4-11. Handwheel-operated pinch valve 43
4-12. A boiled-bonnet bellows seal globe valve 43
4-13. Rupture disk 43
4-14. Closed-loop sampling system (to avoid losses from sampling) 43
4-15. Open-ended lines 44
5-1. National VOC emissions—stationary sources 48
6-1. Hazardous waste characteristics 53
6-2. Hazardous waste generator statistics—number of generators by generator size 53
6-3. Hazardous waste generator statistics—waste quantity by generator size 54
8-1. Vent sampling 66
8-2. Isolation flux chamber and supporting equipment 66
8-3. Concentration-profile technology 67
8-4. Transect technology 68
-------
Figures (continued)
8-5. Mass balance approach 68
8-6. Open liquid surfaces—modeling approach 69
8-7. Effect of volatility on emissions from a surface impoundment 70
8-8. Effect of residence time on emissions from an impoundment 70
8-9. Fate of organics: emissions, effluent, biodegradation, sludge 71
8-10. Topical model inputs (liquid surfaces) 71
8-11. Model inputs for an aerated lagoon 72
8-12. Air porosity vs. total porosity .72
8-13. Land treatment emission mechanisms. 72
8-14. Typical model inputs (porous solids) 73
8-15. Model inputs for land treatment 73
8-16. Model inputs for a covered landfill 73
9-1. Benzene waste operations NESHAP reporting requirements 78
10-1. Wastewater treatment system showing benzene concentrations and flow rates: Example 1 82
10-2. Wastewater treatment system showing benzene concentrations and flow rates: Example 2 83
10-3. Wastewater treatment system showing benzene concentrations and flow rates: Example 3 83
10-3a. Wastewater treatment system showing benzene concentrations and flow rates:
Examples; Solution A 84
10-3b. Wastewater treatment system showing benzene concentrations and flow rates:
ExampleS; Solution B ....84
10-4. ABC Oil Refinery wastewater treatment system—case study problem.
(Annual average benzene concentration and annual benzene quantity shown for each
wastewater stream.) 85
10-5. ABC Oil Refinery wastewater treatment system—case study solution 87
11-1. Facility XYZ case study 90
11-2. Case study of Facility XYZ wastewater treatment plant (WWT) with NPDES permit 91
12-1. Flow schematic of one type of flame-ionization analyzer. .;.. 96
12-2. Photograph of the front of one type of flame-ionization analyzer 97
12-3. Lamp inside analyzer and window on surface of lamp 97
12-4. Photoionization lamp on the end of an umbilical cord 98
12-5. Catalytic combustion analyzer. '. 98
VI
-------
Tables
Page
1-1. Standards Development Under Section 3004(n) 4
1-2. Clean Air Act ; ...6
1-3. CERCLA/SARA (Superfund) , 7
2-1. Major Factors Affecting Emissions 12
3-1. Questions on Details 27
3-2. Units Affected ....... 28
3-3. How the Regulations Work .30
4-1. Highlights „„ 35
4-2. Topics ..„ 35
4-3. Equipment Covered by Subpart BB 36
4-4. Applicability of Organic Content Analytical Methods ....39
4-5. Applicability of Organic Analytical Detectors 39
4-6. Light/Heavy Liquid Determination 39
4-7. Leak Detection Monitoring with Method 21 , 40
4-8. Control Requirements, Subpart BB Equipment Leak Rules, Summary ,42
4-9. Equipment Leak Model Units 44
4-10. Equipment Leak Impacts 44
4-11. General Records Required , 44
4-12. Information Required in Semiannual Reports (264.1065) 45
4-13. Equipment Leak Rules 45
4-14. Types of Equipment Leak Standards .'. 45
6-1. RCRA Hazardous Waste Program—Title 40, Code of Federal Regulations... 52
6-2. HSWA Schedule for Submitting Part B Permit Applications ...; 55
9-1. Background of Benzene Waste Operations NESHAP 75
9-2. Total Annual Benzene in Waste (TAB) 76
9-3. Process Wastewater Exclusions 76
9-4. Alternative Standards for WWTS ..77
9-5. Benzene Waste Operations NESHAP—General Control Requirements 77
9-6. Initial Determination of TAB „ 78
9-7. Certification of Compliance 78
10-1. Case Study Problem 85
10-2. Case Study Solution 86
11-1. Process Vent Emission Rate (ER) and Operating Hour (OH) Data •. 92
VII
-------
Tables (continued)
11-2. Review of RCRA Air Emissions Standard for Process Vents from Hazardous Wastes
TSDF Operations—Case Study 93
12-1. Overview 95
12-2. Catalytic Combusion Analyzer Exposed to 10,000 ppm Methanol Vapors 100
12-3. Flame-ionization Analyzer Used to Detect Orthochlorotoluene Vapors 100
12-4. Catalytic Combusion Analyzer Used to Detect Tetrachloroethane Vapors 100
12-5. Response Factors at Various Concentrations, Example 1 •. 100
12-6. Response Factors at Various Concentrations, Example 2 100
f
12-7. Response Factors at Various Concentrations, Example 3 ; 100
12-8. Instrument Variations, Example 4 101
12-9. Instrument Variations, Example 5 101
12-10. Health and Safety Considerations 102
12-11. Comparison of Available Instruments 103
VIII
-------
Acknowledgments
This seminar publication was prepared by Research Triangle Institute (RTI) under
contract to the Office of Air Quality Planning and Standards (OAQPS). It contains the
presentations of the speakers at the seminar series conducted from August 1990 to March
1991. The seminars were sponsored jointly by OAQPS and the Office of Research and
Development (ORD). Many persons were involved in the development of these seminars
and the presentations. They include:
EPA, OAQPS
K. C. Hustvedt
Robert B. Lucas
Susan R. Wyatt
EPA, Office of Solid Waste
Ginger Freedman
Frank McAlister
James Michael
A.T. Kearney, Inc.
Mitchell Baer
RTI
Marvin R. Branscombe
David W. Coy
F. Graham Fitzsimons-
Robert G. Hetes
Paul R. Peterson
Terrence K. Pierson
Robert A. Zerbonia
PEER Consultants, P.C.
Donovan S. Duvall
Andrew W. Weisman
Justice A. Manning, the Center for Environmental Research Information, ORD,
coordinated the workshops with assistance from PEER Consultants, P.C. Peer review was
provided by several persons at RTI and OAQPS. Special appreciation is expressed to Bob
Zerbonia who worked tirelessly with CERI in bringing this document to completion. Bob
Zerbonia and Bob Lucas provided a final review.
* Formerly RTI; currently EC/R
IX
-------
Introduction
The organic chemicals contained in wastes processed during waste management operations can
volatilize into the atmosphere and cause toxic or carcinogenic effects or contribute to ozone
formation. Because air emissions from waste management operations pose a threat to human health
and the environment, regulations were developed to control organic air emissions from these
operations. In June of 1990, the Environmental Protection Agency (EPA) promulgated standards
under the authority of Section 3004 of the Hazardous and Solid Waste Amendments to the Resource
Conservation and Recovery Act (RCRA). The standards limit organic air emissions as a class from
process vents and equipment leaks at hazardous waste treatment, storage, and disposal facilities
requiring a permit under Subtitle C of RCRA. Additional RCRA standards are under development.
On July 22,1991, EPA proposed, under RCRA authority, organic air emission standards for tanks,
surface impoundments, and containers at hazardous waste treatment, storage, and disposal facilities
(56 FR 33491). In March of 1990, the EPA promulgated standards under the authority of Section
112 of the Clean Air Act (CAA) that limit emissions of benzene from benzene waste operations.
To improve the understanding of the recently proposed and promulgated air rules that apply to
waste management operations and to ensure that EPA, state, and local permit writers and enforce-
ment personnel and the regulated community receive consistent guidance related to implementa-
tion, compliance, and enforcement activities, EPA conducted a series of workshops focusing on
these rules. Presentations and case studies focus on waste management sources of air emissions,
control technologies, and the RCRA and CAA regulations. This workshop was sponsored jointly by
EPA's Office of Air Quality Planning and Standards and the Office of Research and Development,
with support from the Office of Solid Waste and Emergency Response. Technical support for the
workshops was provided by Research Triangle Institute; logistical support for the workshops was
provided by PEER Consultants, P.C.
At the end of each chapter is a select list of questions either submitted by the attendees or asked
of the speakers at the conclusion of their presentations. Answers based on the best information
available at the time were given onsite and summarized here.
-------
Workshop Schedule
Boston, MA
Elizabeth, NJ
Chicago, IL
Atlanta GA
Dallas, TX
Sacramento, CA
Seattle, WA
Kansas City, MO
Philadelphia, PA
Denver, CO
August 28-30, 1990
September 11-13, 1990
October 23-25, 1990
November 13-15, 1990
December 11-13, 1990
January 15-17, 1991
January 22-24, 1991
February 12-14, 1991
February 26-28, 1991
March 26-28, 1991
Since the regulatory scene is dynamic, some statements in this publication may be dated. As can
be seen from the above dates, these workshops were completed over a year ago. Information was
accurate then. If questions arise concerning TSDFs from reading material in this publication, the
reader should contact:
Air Questions
Bob Lucas (919) 541-0884
RCRA Permitting Questions
Frank McAlister (202) 260-2223
XI
-------
-------
Chapter 1
Air Pollution Overview
Abstract
A broad overview of the need to control organic air
emissions is provided in this introductory chapter. Human
health and environmental problems caused by organic air
emissions or problems to which organic air emissions
contribute are discussed. Major .problems discussed are
those resulting from tropospheric ozone formation and
exposure to air toxics. Other problems discussed include
stratospheric ozone depletion, global climate change, and
acid rain. The statutory mechanisms under which organic
air emissions are regulated are discussed, with emphasis
on the Clean Air Act and the Resource Conservation and
Recovery Act (RCRA). The specific rules that apply to
waste management operations and that are the focus of
the workshop are introduced. These are the rules devel-
oped by the U.S. Environmental Protection Agency (EPA)
under RCRA Section 3004(n) that apply to RCRA-permit-
ted hazardous waste treatment, storage, and disposal fa-
cilities (TSDFs) and the rule promulgated under Section
112 of the Clean Air Act that limits emissions from ben-
zene waste operations.
Overview
Organic gaseous emissions are the focus of this chapter
because the air emissions standards that are the subject of this
workshop are those being developed by the Office of Air
Quality Planning and Standards (OAQPS) to address organic
emissions from several waste management sources. However,
other types of emissions also occur from waste management
sources, such as inorganic gaseous emissions (e.g., metals)
and paniculate emissions, that are subject to regulation through
other programs. For example, the Office of Solid Waste
(OSW) has proposed standards for emissions from industrial
boilers and furnaces that include requirements for metals.
General requirements exist that limit blowing dust (particu-
lates) from landfills and waste piles at hazardous waste treat-
ment, storage, and disposal facilities (TSDFs). The EPA also
has developed a Hazardous Waste TSDF - Fugitive Panicu-
late Matter Air Emissions Guidance Document (EPA-450/3-
89-019) that deals with controlling these emissions.
Why are we concerned about organic gaseous emissions?
Two major concerns are ozone and air toxics.
Ozone
Ozone in the atmosphere is illustrated in Figure 1-1.
Ozone is both a blessing and a curse, in relation to human
health and environmental effects. It exists naturally in the
upper atmosphere (the stratosphere) and in the lower atmo-
sphere (the troposphere). Ozone is a blessing in the strato-
sphere; it protects us from the sun's radiation. However, in the
lower atmosphere, exposure to ozone results in negative health
effects on humans and other adverse environmental impacts.
The way ozone is formed in the lower atmosphere is
depicted very simplistically in Figure 1-2. The primary ingre-
dients are nitrogen oxides, organic compounds, and solar
radiation. Emission of nitrogen oxides come primarily from
combustion sources. Major stationary sources of NOX are
coal-fired power plants. Transportation sources (automobiles,
trucks, buses) are also big NO^ sources. Organic compounds
come from a variety of sources, including waste management
operations.
In the presence of sunlight, nitrogen oxide and organic
compounds go through a series of complex chemical reac-
tions, and two principal by-products are formed. One is ozone,
identified by the symbol O3, and the other is an aerosol that,
Solar
radiation
:•: :•: :•: :•: :-.Stratospheric ozqnex |.| :•: •••Stratosphere
'•— ' ' """ ~ =-•• • • i"4iXi.
Tropospheric ozone Troposphere
XVVV'O
Surface
Stratospheric ozone ("good ozone")
provides protection from the sun's radiation
Tropospheric ozone ("bad ozone")
is detrimental to human health and welfare
Figure 1-1. Ozone in the atmosphere.
-------
among other things, restricts visibility. The combination of
these is referred to as photochemical smog. Human exposure
to ozone can affect the respiratory system. Impacts include
inflammation of the lungs, impaired breathing, reduced breath-
ing capacity, coughing, chest pain, nausea, and general irrita-
tion of the respiratory passages. The results of long-term
ozone exposure can include increased susceptibility to respi-
ratory infections, permanent damage to lung tissues, and
severe restrictions on breathing capacity. Certain subpopula-
tion groups, such as the very young, the elderly, and those
with preexisting respiratory conditions, are more sensitive to
exposure to ozone than the normal, healthy, adult population.
However, healthy, young individuals can also be subject to
negative health impacts if exposed to ozone during exercise.
Studies have been conducted to determine the existence
and extent of the human health impacts of ozone. For ex-
ample, in a study in 1988 of several hundred deceased persons
in Los Angeles, all believed to be accident victims and other-
wise healthy, about half were found to have lesions in their
lungs, characteristic of the early stages of lung disease (Figure
1-3).
Welfare effects are associated with ozone exposure. Ma-
terial damage due to oxidation may occur. Synthetic and
rubber compounds, for example, have a much shorter useful
life in an ozone-laden environment Reduction in crop fields,
lower forest growth rate, and premature leaf droppage also
may occur. EPA recently estimated that between $2 billion
and $3 billion worth of annual damage to commercial crops
and forests was due to zone exposure. Visibility impairment
can also be considered a welfare impact of photochemical
smog.
EPA is charged under the Clean Air Act (CAA) to
establish national ambient air quality standards for pollutants
including ozone. One measure of how extensive the ozone
problem is in the United States is to compare air quality
monitoring data with the health-based ambient air quality
standard. The national ambient air quality standard (NAAQS)
for ozone was set at 0.12 ppm (an hourly average not to be
exceeded more than once annually)., Historical monitoring
data indicate that the national ambient air quality standard has
been exceeded routinely in more than 60 areas nationwide.
Over 100 million people live in these areas. Recent data
indicate some improvement from these figures, but the ambi-
ent air quality standard for ozone is still being exceeded in
many areas that contain a significant portion of the total
population of the United States. Furthermore, some areas may
not attain the ambient air quality standard for many years. The
CAA amendments of 1990 contain provisions that address
"nonattainment" areas; that is, areas not attaining the ambient
air quality standards for several "criteria" pollutants, includ-
ing ozone. Under this new law, areas with extreme ozone
nonattainment problems have 20 years to attain the ozone
ambient air quality standard.
More stringent standards for oirone have been called
for—particularly with regard to sensitive populations for whom
0.12 ppm may not be low enough.
A map of the United States highli ghting areas exceeding
the ambient ozone standard, based on data collected in 1986
and 1988, is shown in Figure 1-4. Although the largest urban
areas, such as the Los Angeles area, Chicago, Houston, and
the northeast corridor, are the "hot spots" for ozone, many
other areas across the United States also have an ozone
problem. In addition, due to the transport of ozone precursors,
the ozone NAAQS is exceeded in areas of the country far
Figure 1-2. Tropospheric ozone formation.
-------
Figure 1-3. Photograph of lung from 19-year-old accident
victim in Los Angeles showing lung damage
possibly due to ozone exposure.
removed from urban centers. Some of the national parks, for
example, have been observed to exceed the ozone ambient air
quality standard occasionally.
The relative contribution of various source categories to
total nationwide emissions of volatile organic compounds
(VOCs) is shown in Figure 1-5. In EPA terminology, a VOC
is an organic compound that is believed to participate in ozone
formation. As shown, hazardous waste TSDFs are a signifi-
cant source, contributing an estimated 8 percent of total VOC
emissions.
Air Toxics
In general, air toxics are air pollutants that cause cancer
or other human health effects.One hundred ninety compounds
are specifically identified in the CAA amendments of 1990 as
air toxics that EPA must investigate and potentially regulate.
A significant number of those 190 are organic compounds.
Many point and area sources of air toxic emissions exist.
These include large point sources such as chemical plants,
petroleum refineries, and power plants. Smaller and more
widespread sources, such as dry cleaners, can also be sources
of air toxic emissions. Waste management sources also con-
tribute to air toxics and are widespread. A recent count of
TSDFs by the EPA OSW indicated about 2,600 to 3,000
potentially permitted TSDFs.
Each air pollutant produces characteristic health effects,
which can occur due to acute (short-term) exposure or chronic
(long-term) exposure. Exposure to air toxics affect neurologi-
Figure 1-4. Areas exceeding the ozone NAAQS.
-------
Industrial Processes 2%
Surface Coating 14%
Petroleum Marketing 10%
Petroleum Refining 3%
Mobile Sources 32%
Misc. Sources 13%
Hazardous Waste TSDF 8%
Chemical Manufacture 2%
Misc.-Solvent Uses 1i6%
Figure 1-5. Sources of nationwide VOC emissions.
cal, respiratory, and reproductive systems. Some air toxics,
such as benzene, also may cause cancer. Two EPA measures
of health effects are used to identify or quantify the impacts of
carcinogenic air toxics. One is individual risk, expressed as a
statistical probability, that indicates an individual's increased
risk of contracting cancer when exposed to a particular con-
centration of a pollutant over a 70-year lifetime. The other
measure is an indication of population risk expressed as the
number of cancer incidences per year expected nationwide
due to exposure to that pollutant
Recently, major U.S. industries began reporting the amount
of toxic chemicals released to the air, land, and water as
required by the Superfund Amendments and Reauthorization
Act (SARA), Section 313. Industry reported that in 1987
about 2.4 billion pounds of toxic pollutants were emitted to
the air. Air toxics are estimated by EPA to account for
between 1,600 and 3,000 cancer deaths per year, and the
average urban individual lifetime risk of contracting cancer
due to exposure to air toxics is estimated to be as high as 1 in
1,000.
For treatment, storage, and disposal facilities, a prelimi-
nary estimate indicates a national population risk of about 140
cancer incidences per year and a maximum individual risk of
2 in 100 possibly caused by air toxic emissions from these
facilities.
The top 14 VOCs and air toxics (also referred to as
"hazardous air pollutants" (HAPs)) on a mass emission basis
are shown in Figure 1-6. Mass of emissions alone, however,
does not indicate the relative severity of the problems associ-
ated with air toxics. The toxicity of each compound and the
degree of exposure that occurs (e.g., time and concentration)
are equally important and must be considered. Toluene, for
example, is the most emitted compound but is less toxic than
benzene, a carcinogen linked to leukemia.
Laws That Address Organic Air Emissions
Several major environmental laws address organic air
emissions. These include the CAA, which is specifically
designed to address major air pollution problems in the United
States; the RCRA, as amended by the Hazardous and Solid
Waste Amendments; and the Comprehensive Environmental
Response, Compensation, and Liability Act (CERCLA), as
amended by SARA.
Most of the new air standards described in this workshop
are being developed under RCRA. Section 3004(n) directs the
EPA Administrator to establish standsirds for the monitoring
and control of air emissions from treatment, storage, and
disposal facilities, as necessary, to protect public health and
welfare. The standards developed under RCRA 3004(n) are to
be implemented through the RCRA permit system established
for hazardous waste management unitsi.
Table 1-1. Standards Development Under Section 3004(n)
Phase I Total organics
Process vents and equipment leaks
Promulgated 6/21/90 ((55 FR 25454)
Phase II Total organics
Tanks, surface impoundments, containers
and miscellaneous units
• Proposal package in OMB
Phase III • Individual constituent standards, as needed,
to supplement Phase I and Phase II
standards
' • Early Work Group stags
-------
I Toluene
[ Formaldehyde
| Methylene chloride
| Methyl chloroform
I Ethylene
j m-Xylene
Benzene
o-Xylene
Perchloroethylene
] p-Xylene
Chlorobenzene
Acetic acid
Trichlorotrifluoroethane
Trichloroethylene
Figure 1-6. Top fourteen VOC/HAP chemicals.
As illustrated in Tablel-1, the EPA is developing the
RCRA 3004(n) air standards in three phases. Organic emis-
sions from process vents associated with specific noncombus-
tion waste treatment processes (e.g., stream stripping and
thin-film evaporation units) as well as equipment leaks from
pumps, valves, and pipe fittings are addressed in Phase I.
Final Standards for these sources were promulgated June 21,
1990 (refer to Subparts AA and BB in the Code of Federal
Regulations (CFR), Title 40, Parts 264 and 265 (40 CFR 264
and 265)). Organic emissions from tanks, surface impound-
ments, containers, and miscellaneous units are addressed in
Phase II. Standards for these sources were proposed in July
1991 as a new Subpart CC in 40 CFR Parts 264 and 265.
Current analyses indicate that a potential residual risk prob-
lem may remain after implementation of the Phase I and Phase
II standards for organics. Therefore, emissions of individual
chemical constituents as necessary to bring the residual maxi-
mum individual risk to within an acceptable range under
RCRA (104 to 10-*) will be addressed in Phase III. Proposal of
standards, as needed, under Phase III is planned to be concur-
rent with promulgation of the Phase II standards.
The Corrective Action Program is also under RCRA.
Under the Corrective Action Program, solid waste manage-
ment units have to go through a site-specific facility evalua-
tion. Site-specific evaluation and risk assessment also include
consideration of air emissions. In addition, the land disposal
restrictions (LDR) promulgated under RCRA affect air emis-
sions. The LDR prohibit the depositing of hazardous waste on
or into land disposal sources such as landfills, surface im-
poundments, and waste piles unless certain treatment require-
ments are met. Treatment of wastes to meet the LDR can
result in air emissions if the treatment process is not properly
controlled, and the RCRA 3004(n) air standards work in
concert with the LDR to prevent this potential cross-media
pollution.
Other programs under RCRA, such as one that estab-
lishes location standards for the siting of new facilities, also
require consideration of air emissions.
An overview of hazardous waste management is shown
in Figure 1-7. Once a hazardous waste is generated, it may go
through a series of different processes and waste management
units before disposal. Waste may be stored or treated, for
example, in tanks and containers. Containers include 55-
gallon drums, dumpsters, tank trucks, and railcars. Waste
treatment to meet the requirements of the LDR may take place
early in the waste management process, or just prior to dis-
posal. Further, the management of hazardous waste may take
place at the generator site (onsite) or at a commercial TSDF
(offsite). If a waste is managed offsite, it may also be handled
at a storage and transfer station before being transported to
another location for final treatment and disposal.
In Figure 1-8, coverage of the Phase I and Phase II RCRA
air standards is overlaid onto the hazardous waste manage-
ment units illustrated in Figure 1-7. In the Phase I standards,
process vent organic air emissions from treatment units spe-
cifically identified in the standards are limited, and equipment
leak emissions from other waste management units are limited
also.
Coverage of the RCRA air standards would be expanded
by the Phase II standards to address organic air emissions
from tanks, surface impoundments, and containers. As is
discussed in more detail in later workshop chapters, the Phase
II standards are designed to contain (or suppress) potential
organic emissions from escaping prior to treatment. Accord-
ing to the standards, operators would be required, for ex-
ample, to cover open tanks unless the concentration of organic
waste contained in a tank could be demonstrated to be below a
specified value. Because control requirements are triggered
by the organic content of the waste, these standards are
"waste-based" rules. Waste treatment is not required, accord-
ing to the Phase II RCRA air standards, but is required by the
LDR. The benzene waste national emissions standards for
hazardous air pollutants (NESHAP), also discussed in this
workshop, requires containment-type controls prior to treat-
ment similar to the Phase II RCRA air standards. Unlike the
Phase II standards, however, treatment requirements for ben-
zene-containing wastes are included in the benzene waste
NESHAP.
Clean Air Act
Major regulatory programs established under the CAA
that are used to address organic air emissions, including ozone
precursors and air toxics, are shown in Table 1-2.
As referenced earlier, NAAQS are established by EPA
for "criteria" pollutants, and the states then set standards to
attain and maintain them. Ozone is a criteria pollutant, and
-------
Waste
Generation
90-Day
Tanks
Figure 1-7. Hazardous waste management.
Waste Handling and
Treatment
Treatment
Units
e.g:
Steam
Stripper
Waste
Disposal
Containers
\
8*0 B
•boil
TIOQI
Tanks & Surface Impoundments
Land
Disposal
Units
volatile organic compounds are regulated by the states as
ozone precursors on a source-by-source basis. The new source
performance standards (NSPS), set under Section 111 of the
CAA, are designed to address emissions of the criteria pollut-
ants from new, modified, or reconstructed stationary sources.
"Designated pollutants" may also be addressed by NSPS. A
designated pollutant is a noncriteria pollutant that is identified
by EPA for regulation under Section lll(d), based on health
or welfare impacts. Examples of designated pollutants are
total reduced sulfur (TRS) and sulfuric acid mist NESHAP
are set under Section 112 of the Clean Air Act to limit
emissions of pollutants identified as hazardous from both
existing and new stationary sources. Section 112 was changed
substantially by the 1990 CAA amendments. The "old" Sec-
Table 1-2. Clean Air Act
National Ambient Air Quality Standards (NAAQS)
- Criteria pollutants
- PM, SOj, CO, NOX, O3, Pb
New Source Performance Standards (NSPS)
- Criteria pollutants
- Designated pollutants (e.g., TRS)
National Emission Standards for Hazardous Air
Pollutants (NESHAP)
tion 112 required EPA first to list a pollutant as hazardous and
then to establish standards to protect public health "with an
ample margin of safety." In the new Section 112, EPA must
establish technology-based standard!! for sources of 190 haz-
ardous pollutants listed in the new law. At a later time, more
stringent standards are required if risk assessments indicate
that the technology-based standards are not adequately pro-
tective.
A NESHAP for benzene waste operations was completed
recently and is the last NESHAP set under the "old" Section
112. It was promulgated in March 1990 and is codified in 40
CFR 61, Subpart FF. It applies to chemical plants, petroleum
refineries, coke by-product recovery facilities, and certain
treatment, storage, and disposal facilities. The compliance
deadline for existing facilities to install the controls that are
required by this standard is March 7,1992. The benzene waste
NESHAP is described more fully in later chapters.
CERCLA (Superfund)
The cleanup of inactive contaminated sites is mandated in
CERCLA. As shown in Table 1-3, several aspects of CERCLA
are important in the control of organic air emissions. A site-
specific risk analysis must be conducted prior to a removal
and remediation action under Superfund, and this site-specific
analysis must include a consideration of air emissions that
may result from the cleanup. For example, ground-water
-------
Waste
Generation
Waste Handling and
Treatment
Treatment
Units
e.g.
Steam
Stripper
Phase 1
Process Vent
Standards
Phase 1
Equipment Leak Standards
Phase 2
Emission
Standards
Tanks & Surface Impoundments
Waste
Disposal
Land
Disposal
Units
Figure 1-8. Phases I and II RCRA air standards overlaid onto hazardous waste management.
stripping to remove an organic contaminant could result in a
potential cross-media problem if air emissions created by the
treatment process were not controlled. In addition, removal
and remediation actions must comply with those existing laws
that are applicable or relevant and appropriate requirements
(ARARs). As will be discussed later, the Phase I RCRA air
standards may be ARARs for some cleanup operations under
Superfund.
Finally, the toxic release inventory required by SARA
Title 313 is also an important tool for addressing air toxics. In
a very broad sense, this inventory is helping to improve EPA's
knowledge of the sources of toxic air pollutants. SARA Title
313 was one of the databases that EPA reviewed recently in
Table 1-3. CERCLA/SARA (Superfund)
Site-specific risk analysis required for removal and
remediation actions
Removal and remediation actions must comply with
federal and state laws that are applicable or relevant
and appropriate (ARARS)
Toxic release inventory required by SARA Title 313
trying to identify sources of the 190 toxic air pollutants listed
under the CAA of 1990.
Some overlap exists in statutory coverage of air emission
sources by the various laws as shown in Figure 1-9. In some
situations, this overtopping coverage will result in the same
source being subject to regulations with different control
requirements. When this occurs, it likely will be because the
applicable regulations were developed under laws with differ-
ent mandates. For example, NSPS under the CAA are technol-
Clean
Air Act
- 3004(n)
- Waste
treatment
standards
RCRA
Control requirements consistent and complimentary to
the extent possible
Compliance must be demonstrated with all applicable
rules
Figure 1-9.
Overlap of statutory coverage for air emission
sources.
-------
ogy-based standards, and the RCRA 3004(n) air standards are
risk-based. Where different standards apply, compliance must
be demonstrated with all applicable rules. However, when
possible, EPA will make the control requirements of rules that
apply to the same sources consistent and complementary.
An example of this overlapping coverage related to waste
management is storage tanks. As illustrated in Figure 1-10,
storage tanks may be covered by three separate rules. Tanks in
which benzene-containing waste is stored at chemical plants,
petroleum refineries, coke by-product plants, and certain TSDF
are covered by the benzene waste NESHAP (40 CFR Part 61,
Subpart FF). New, modified, or reconstructed tanks contain-
ing volatile organic liquids (VOLs) and those above certain
size limits are covered by the NSPS for VOL storage (40 CFR
, Part 60, Subpart Kb). Finally, the RCRA Phase II air stan-
dards will apply to tanks in which organic hazardous waste is
managed. Depending on the particular physical characteristics
of the tank, the waste being stored, and the age of the tank, the
same tank could be covered by the benzene waste NESHAP,
the VOL storage NSPS, and the RCRA Phase II air standards.
The ramifications of this overlap for owner/operators are
minimal, however, because, if an owner/operator is comply-
ing with the control requirements of any one of the standards,
he or she will be in compliance with the control requirements
of all three.
Conclusions
Organic air emissions contribute to major air pollution
problems, including ozone formation in the lower atmosphere
and air toxics. Waste management operations are a significant
source of organic air emissions and are being regulated under
several federal laws. The applicability and specific require-
ments of the various regulations issued and under develop-
ment will be discussed in subsequent chapters of this course.
Questions and Answers
Question—Regarding the location of ozone problems in the
lower atmosphere, where do the problems occur in terms
of emission sources or locations? Is the transport of VOC
a factor?
Answer—This oxidizing type of pollution is generally found
in urban areas. It results from chemical reaction of NOx
and HC in sunlight and produces O3, PAN, and other
complex compounds. The pollution is expressed as ozone
and referred to as photochemical oxidants. Because it is a
secondary pollutant, transport is a concern. Ozone is a
regional problem with impacts 'Occurring up to 250 km
from the source.
Question—If ozone is depleted in the upper atmosphere, why
is it not depleted in the lower atmosphere?
Answer—Ozone is short-lived in the lower atmosphere. The
concentration follows a daily cycle with peaks around
noon decreasing to near zero levels after midnight, as the
intensity of solar radiation diminishes. Ozone in the
upper atmosphere (~ 30 km) is formed by photodissocia-
tion of oxygen.
Question—Regarding the ozone NAAQS, does a link exist
between the concentration of 0.12 ppm and when health
effects take place?
Answer—The ozone NAAQS is a health-based standard, but
debate exists on the level that; provides an adequate
margin of safety.
f^N^-V-^jV-V-v^N
Storage Tanks
Figure 1-10. Storage tanks under several "regulatory umbrel-
las."
Question—Is a copy of the hazardous pollutant list available?
Do -standards exist for these compounds; existing limits
on emission rates from facilities?
Answer—No standards exist on emission rates; some emis-
sion measurements are available.
Question—Why are we concentrating on benzene from among
the entire list of 190 hazardous air pollutants?
Answer—A court order has been issued on the benzene
regulations.
Question—Can you summarize when RCRA and when CAA
has jurisdiction? How do the new CAA amendments
overlap with the RCRA process vent rules?
Answer—Both say protect and the CAA says "be consistent"
with RCRA rules. Guidance for VOC control is being
issued in the process vent alternative control technology;
RCRA-exempt WWTS maximum achievable control tech-
nology (MACT) standards (technology based for HAPs)
will be developed. Title 5 permits still may be needed for
RCRA vents.
8
-------
Question—Could you be more specific as to what impacts
organic air emissions have on global climate change and
acid rain, and the specific organics that cause these
impacts? What are the "greenhouse gases"?
Answer—The greenhouse gases are CO2, HjO, CH4> NO2, and
CFCs; concentrations are increasing.
Question—Regarding maximum individual cancer risk, is it
onsite, offsite, 24-hour exposure, lifetime, or nationwide?
Is the risk for TSDF sources evaluated separately from
the risk from production processes?
Answer—The risk is evaluated at the fenceline. It represents
the nationwide maximum individual cancer risk resulting
from lifetime exposure.
-------
-------
Chapter 2
Emission Sources and Controls
Abstract
The major sources of air emissions at waste manage-
ment facilities, how these emissions occur, and their con-
trol are the focus of this chapter. The major sources that
are discussed in detail include surface impoundments, the
very broad and diverse category of tanks and ancillary
equipment, containers, and other major land disposal
sources. As each source is described, controls that are
inherent to that source or commonly found on that par-
ticular source are presented. In addition, details are pro-
vided on the basic mechanisms by which emissions occur
and the major factors that affect the emissions.
After the discussion of sources and their inherent
controls, air pollution control devices that may be gener-
ally applicable to any enclosed or vented source (i.e., add-
on controls) are described. The discussion of control de-
vices focuses on their applicability, control performance,
and the major factors affecting performance. Organic
removal (i.e., pretreatment) and destruction processes are
also discussed as a means of controlling air emissions and
reducing or eliminating the emission potential. This dis-
cussion describes processes that remove or destroy the
organics in the waste, which may eliminate the need to
control subsequent waste processing steps.
Emission Sources and Controls
The types of sources found at waste management facili-
ties, inherent controls that are typically part of the construc-
tion and operation of the sources, and emission mechanisms
are covered in this chapter. As each source is discussed,
covers and enclosures that are specifically applicable to the
source are described, as well as simple work practices that
reduce emissions. Other emission controls that are broadly
applicable to many of the individual sources are discussed
collectively in the second part of this chapter. These controls
include traditional air pollution control devices, processes that
remove the organics before die waste is placed in units with a
high emission potential, and waste incineration.
Sources of Air Emissions
The discussion of emission sources is divided into four
categories: surface impoundments, the very broad and diverse
group of tanks and ancillary equipment, containers, and land
disposal sources that are expected to be most affected by the
land disposal restrictions (LDR). The major focus is on the
first three categories because they are the most directly im-
pacted by the air emission regulations covered in this work-
shop.
Surface Impoundments
A surface impoundment is "a natural topographical de-
pression, man-made excavation, or diked area formed prima-
rily of earthen materials (although it may be lined with man-
made materials) which is designed to hold an accumulation of
liquid wastes or wastes containing free liquids and which is
not an injection well. Examples of surface impoundments are
holding, storage, settling, and aeration pits, ponds, arid la-
goons."
Impoundments are simply ponds and lagoons that are
used primarily for managing aqueous wastes and sludges.
They are certainly land disposal sources, but they are dis-
cussed separately because of continued use after LDR is in
place, and because they may continue to be major sources of
air emissions. For example, surface impoundments that are
dredged annually may be exempted from LDR.
A surface impoundment is below grade, usually has
berms with sloping sides to contain wastes, and has a liquid
surface that is exposed to the atmosphere. It may be operated
as a flowthrough system with liquid flowing in at one point
and out at the same time at another point, or the liquid may be
pumped out or evaporated, leaving behind a sludge. Surface
impoundments are commonly part of wastewater treatment
processes and are used for storage, equalization of different
waste streams, neutralization, biodegradation, or other pro-
cesses.
Surface impoundments have a very high emission poten-
tial for volatile organics for several reasons. These impound-
ments have large exposed surface areas that range in size up to
several acres. In addition, the residence time of the waste in
the impoundment is on the order of days, weeks, or months,
which results in the loss of most of the volatiles.
Several of the factors that affect emissions from im-
poundments are listed in Table 2-1. These same factors are
applicable to emissions from open tanks. The constituent's
volatility has a direct effect on emissions from impoundments
and other sources with exposed liquid surfaces. Highly vola-
tile compounds such as benzene are readily emitted from open
11
-------
Tibte 2-1. Major Factors Affecting Emissions
Constiuent volatility
Residence time
Surface area
Turbulence (aeration, agitation)
Wlndspeed and temperature
Extent of competing mechanisms (such as
biodegradatlon)
sources, whereas relatively nonvolatile compounds such as
phenol tend to stay in the water.
The residence time in the impoundment has an obvious
effect on emissions: longer residence times result in higher
emissions. If the waste is in the impoundment long enough,
even relatively nonvolatile compounds are evaporated. For
impoundments with relatively short residence times, a higher
percentage of the organic may be removed with the effluent
and emitted later in other units in the treatment sequence.
Many impoundments and tanks are agitated for mixing,
air stripping, or biodegradation. Agitation, and aeration in-
crease emissions by creating turbulent zones and increase
contact between the waste and air. A highly turbulent area and
water spray around the agitators used in mechanically aerated
units exists. Essentially all of the highly volatile compounds
can be emitted when the impoundment is mechanically agi-
tated. Approximately half of the impoundments used to treat
hazardous waste are aerated or agitated.
As is illustrated in Figure 2-1, emissions from impound-
ments occur from wind blowing across the exposed surface of
the waste. Organics can also be removed by biodegradation,
adsorption onto sludge, or removed with the effluent Emis-
sion models have been developed to estimate the extent of
each of these different removal mechanisms.
The models developed for open liquid surfaces are appli-
cable to both impoundments and open tanks. These models
can account for relatively calm surfaces or the emissions from
the turbulence created by aeration or agitation. The emissions
arc modeled as two mass transfer steps in series: (1) diffusion
through the liquid, and (2) mass transfer from the surface of
the liquid to the air. The approach can account for removal in
flowthrough systems and removal in units designed for dis-
Emissions
Wind->
Row In
Figure 2-1.
Flow Out
Sludge
Out
Fate of organlcs: emissions, effluent, biodegrada-
tion, sludge.
posal or evaporation. The extent of biodegradation, if any, can
also be estimated.
One of the controls demonstrated for impoundments is an
air-supported structure, which uses fans to maintain a positive
pressure to inflate the structure. For effective control, the air
vented from the structure must be sent to a control device,
such as a carbon adsorber. Air-supported structures have been
used as enclosures for conveyors, open top tanks, and storage
piles, as well as impoundments.
An air-supported structure and control device has been
installed on a 1-acre aerated lagoon that is used for biodegra-
dation at a pharmaceutical manufacturing facility. The cover
material is a PVC-coated polyesteir with a Tedlar backing.
Agitators are used inside the structure to provide oxygen and
to keep carbon andbiomass suspended. In this application, the
exhaust from the structure is vented to a carbon adsorber.
Very few leaks were found around the structure; conse-
quently, the control efficiency is determined primarily by how
well the control device works. Thiss plant's experience with
the air-supported structure has found that corrosion can be
accelerated inside the structure and that special worker safety
precautions are needed.
Floating membrane covers are a nother control option and
have been demonstrated on various types of impoundments,
including water reservoirs in the western parts of the United
States. For proper operation as a control technique for organic
compounds, the membrane must provide a seal at the edge of
the impoundment and provisions made to remove rainwater.
If gas is generated under the cover, vents and a control device
may be needed. In addition, if sludge accumulates, some
means for periodic sludge removal may be required, such as a
sludge pump.
Emission control depends primarily on the type of mem-
brane, its thickness, and the individual organic compounds in
the waste. Theoretical estimates based on diffusion through
the membrane indicate worst-case control efficiencies of 50 to
over 95 percent. Laboratory studies indicate that the cover is
an efficient control for some organic compounds, and, for
specific compounds that permeate the membrane, the control
efficiency is lower.
The floating membrane cover has been demonstrated on
an impoundment that is used as am anaerobic digester. The
impoundment is about 7 acres in size with a depth of approxi-
mately 14 feet. The membrane material is 100-mil high-
density polyethylene. The cover is finchored over a concrete
ring wall that extends above grade level around the perimeter
of the impoundment. The membrane extends over the con-
crete wall and is covered with backfill to anchor and seal it.
Punctures or tears in the membrane can be patched. This
installation has been in operation for 4 years, and the company
supplying the membrane offered a 20-year warranty on the
life of the material.
Tanks
The most diverse group of sources falls into the category
of tanks, which is broadly defined. If the unit is not a land
disposal source, it is probably a tank. A tank is defined as "a
stationary device, designed to contain an .accumulation of
12
-------
hazardous waste which is constructed primarily of nonearthen
materials (e.g., wood, concrete, steel, plastic) which provide
structural support." A tank system is defined as a tank and its
ancillary equipment, and ancillary equipment includes such
devices as piping, fittings, flanges, pumps, and valves.
The category of tanks and tank systems includes a discus-
sion of those units that are easily identified as tanks, such as
fixed-roof storage tanks. It also includes wastewater treatment
tanks that are typically open; units that perform separation
processes, such as columns used for distillation, absorption,
and solvent extraction; units used for dewatering; and devices
used for waste fixation. The discussion of tanks is divided into
four groups: (1) those used primarily for managing organic
liquids, (2) those used for aqueous wastes, (3) those used for
sludges, and (4) the miscellaneous equipment items associ-
ated with tanks.
Organic Liquids
Organic liquids are usually managed in covered or en-
closed tanks, including those with fixed roofs, those with
floating roofs, and pressure tanks. Fixed-roof tanks are the
most common type of storage tank found at hazardous waste
facilities. Emissions occur through the tank's vent, which may
be open to the atmosphere, equipped with a pressure-vacuum
relief valve, or vented to a pollution control device.
The fixed roof may have several openings in addition to
the vent, such as a manhole for tank entry, a hatch used for
measuring the liquid level, or an overflow pipe (Figure 2-2).
The pressure-vacuum relief valve is also called a conservation
vent, which permits small changes in the liquid level without
pushing out the tank's vapors. If the tank has a conservation
vent or is vented to a control device, the other openings on the
tank must be kept closed and sealed for the emission controls
to be effective.
Emissions from fixed-roof tanks occur primarily by work-
ing losses and, to a lesser extent, by breathing losses. The
quantity emitted is most directly affected by the rate at which
vapors are pushed from the tank and the volatility of the tank's
contents. These emissions are increased by heating or aera-
tion. Working losses occur when waste is pumped into the
tank and vapors are pushed out by the rising level of liquid
(Figure 2-3). Breathing losses occur when the volume of
vapor in the tank is increased because of changes in tempera-
ture or pressure (Figure 2-4).
Equations developed by the American Petroleum Insti-
tute (API) are used to estimate emissions for organic liquids.
The basic form of the equation, which can be used for other
types of wastes, estimates the volume of vapor pushed out
from the amount of liquid pumped in. The concentration of
organics in the vapor can be measured or estimated. One error
in using the API tank equations for aqueous wastes is to
estimate the concentration in the vapor from the mole fraction
of the compound in the liquid, which significantly underesti-
mates concentration. Henry's law constant should be used for
dilute aqueous wastes. Breathing losses are usually very low
compared to working losses and can often be neglected. Note
that if the tank is operated at a constant liquid level, as some
separators and collection tanks are, very little vapor is dis-
placed and working losses are small. •
As an emission control option, fixed-roof tanks can be
retrofitted to open tanks, or a fixed-roof tank can be used to
replace an open tank or impoundment. Compared to an open
tank, a fixed-roof tank can provide additional control of 86 to
99 percent, depending on the waste volatility and the operat-
ing characteristics of the open tank. If the fixed-roof tank is
constructed to withstand pressures of 2.5 psig, an additional
control of 20 to 45 percent can be obtained. (Most tanks are
not designed and constructed to withstand this pressure.)
Floating roof tanks are common at petroleum refineries
and gasoline marketing facilities for the storage of volatile
liquids. The floating roof can be installed internally in a fixed-
roof tank or externally without a fixed roof. The roof floats on
the liquid and moves with changes in the liquid level, thus
controlling working losses. Emissions from a properly main-
tained floating roof are very low and occur from standing
losses and withdrawal losses.
The equipment associated with an external floating roof
tank is shown in Figure 2-5. Standing losses occur at the deck
seals and at openings for fittings in the floating roof. With-
Pressure/Vacuum Valve
(for Venting)
Manhole
Gauge Hatch
] Nozzle
(for Submerged
Fill or Drainage)
Figure 2-2. Typical fixed-roof tank.
13
-------
Working Losses
Due to Loading
Volume of [~
Displaced H
Vapors L-
New Liquid Level
<— Original Liquid
Level
^S<—
Liquid In
Figure 2-3. Covered tanks (working losses).
Breathing Losses
Due to Ambient
Pressure and
Temperature
•- Fluctations
Vapor Phase Concentration in
Equilibrium with Waste Liquid
Volume in
Vapor
Space
Increases
Figure 2-4. Covered tanks (breathing losses).
drawal losses occur from the evaporation of volatiles on the
wetted wall as liquid is removed from the tank and the roof
descends.
If retrofitted to a hazardous waste tank, the floating roof
materials must be compatible with the waste, and floating
roofs cannot be used in hazardous waste treatment tanks with
surface mixers or aeration equipment. The emission reduc-
tions achieved by a floating roof relative to a fixed roof have
been evaluated for volatile organic 1 iquids by using empirical
models. Depending on the type of deck and seal system
selected, emission reductions of 93 to 97 percent can be
obtained. For the smaller size tanks and varieties of wastes
found at hazardous waste facilities, reductions of 74 to 82
percent can be obtained relative to a fixed roof. Converting an
open top tank to a floating roof taiiik is estimated to reduce
emissions by 96 to 99 percent.
Pressure tanks are designed to operate safely at internal
pressures above atmospheric pressure. Consequently, these
tanks can often be operated as closed systems and do not emit
organics at normal storage conditions or during routine load-
ing and withdrawal. Pressure-relief valves on the tanks open
only in the event of improper operation or an emergency to
relieve excess pressure. They are most common for the stor-
age of gases; however, they can also be used to store liquids.
Another type of tank is that used for the distillation of
organic liquids, which is common at solvent recyclers. In
distillation, the more volatile components are separated from
the waste by heating and transferring them to the vapor phase,
which is removed through the overhead system. Distillation
can be performed in a simple heated pot as a batch operation
or in a column as a continuous operation. The device may be
operated at atmospheric pressure, under vacuum, or under
pressure. Emissions occur from the condenser/decanter vent,
vents on collection tanks, and the vacuum system if vacuum is
used (Figure 2-6).
Pontoon Manhole
Seal Envelope
—0
Tank Gauge
Figure 2-5. External floating roof tank.
14
-------
Figure 2-6. Emission sources for distillation.
In a batch still, the waste material is heated and volatiles
are removed to some predetermined cutoff point, such as the
concentration of organics in the condensate or the concentra-
tion remaining in the waste.
Emission models for distillation columns or other separa-
tion devices are not available because the emissions depend
on the types of wastes, the specific organic compounds, and
the design and operating details. However, the emissions from
distillation and other separation devices are usually vented
from a point source and can be measured. In addition, the
operator should have the basic design and performance calcu-
lations mat can provide insight into emission potential, or
material balance calculations that indicate the fate of volatile
compounds.
Solvent extraction is another type of separation process
that has been used for organic liquids. It involves dissolving
the volatile organics in a solvent The solvent is physically
separated from the waste and then recovered for recycle by
distilling off the volatiles. This process has also been demon-
strated for removing benzene from petroleum refinery sludge.
Although 80 to 100 percent of the target organics can be
removed from the waste by the solvent, the overall control
efficiency is probably less. Major emission points associated
with solvent extraction are those involved in the distillation
process used to recover the solvent (Figure 2-7). As discussed
earlier, these emission points include the vent on the con-
denser/decanter and any collection tanks associated with the
unit.
Aqueous Wastes (Wastewater)
Wastewater collection systems are of interest because
some are affected by the NESHAP for benzene waste opera-
tions. The collection system includes individual drains, sew-
ers, and junction boxes. Emissions occur when the wastewater
is in direct contact with the air or from air sweeping through
the collection system from a chimney effect. Our modeling
efforts indicate that 20 to 40 percent of the benzene that is
Solve/
Waste ^
In — *
it
i
r
Solvent
Extractor
Extracted Organic
and Solvent
A
Residual Out
PyfractfiH
Emissions ""'"•'.'*"
Organics
-J t
^ Distillation ) ^1
Figure 2-7. Emissions from solvent extraction.
Solvent
Recycle
present in the wastewater when it is first generated is emitted
in the collection system.
Some of the different ways that the wastewater is drained
from a specific process into the sewer line are shown in Figure
2-8. The open, unsealed drain is the greatest source of emis-
sions from the free fall of the wastewater and vapors from the
sewer. The closed drain essentially eliminates these emis-
sions.
Individual sewer lines from different processes flow
through junction boxes before entering the trunk or main
sewer lines that handle combined flows from different process
areas. The purpose of the junction box is to combine flows, to
permit ready access to the sewer line for cleaning and inspec-
tion, and to isolate vapors from the different individual sewer
lines. A typical junction box that is fitted with a gas-tight
cover and a vent is shown in Figure 2-9. The device also has a
water seal to prevent the flow of air through lines that may be
partially filled with water. This device is operated at a con-
stant liquid level; consequently, emissions from working losses
should be relatively low.
Oil-water separators at petroleum refineries are also part
of collection systems that may require control under the
benzene waste NESHAP. These devices separate oil, water,
and sludge from the wastewater (Figure 2-10).
The most common type of oil-water separator at petro-
leum refineries is the API separator. The separator is a large
rectangular tank with an oil skimmer and the main bay, which
provides a zone for separation. The separator relies on the
different densities of oil, water, and solids: oil and solids
lighter than water float on top of the aqueous phase and
heavier sludges sink to the bottom. Oil is skimmed from the
surface, and heavy sludge is periodically removed from the
bottom of the separator.
Another type of separator in use at refineries is the
corrugated-plate interceptor (CPI). This unit consists of 12 to
48 parallel corrugated plates mounted at an angle. Wastewater
flows downward between the plates with the lighter oil drop-
lets coalescing and floating to the surface. The oil droplets
move up the plates to form a floating layer that is skimmed
from the surface of the tank. These oil-water separators can be
controlled by covering or by covering and venting emissions
to a control device.
Wastewater is usually treated in large open tanks, and the
emission mechanisms are similar to those described for sur-
face impoundments. Generally, these tanks have smaller ex-
posed surface areas and much shorter residence times than
impoundments. This results in somewhat lower emissions
from a single tank compared to a single impoundment; how-
ever, usually several of these tanks in series provide multiple
opportunities for volatiles to be emitted.
Examples of wastewater treatment tanks include large
open tanks used for equalization of wastewater streams from
different processes and tanks that are often aerated or agitated
to provide mixing, to suspend biomass, or to provide oxygen.
Many wastewater treatment processes are performed in open
tanks, such as equalization, neutralization, solids settling, and
biodegradation.
15
-------
777
Drain Pipe
Drain Riser
Drain Pipe
Drain Riser
Sewer Pipe
Cross Section
J
Open, Unsealed
Figure 2-8. Individual drains.
P-Leg Seal
Illl/lli
Drain Pipe
Drain Riser
Closed Drain
-Vent
7777-
Gas Tight Cover
Grade
•;•
>-
TV
'."•Mr: ;.Vf :$•»£••"••""'.•* '•
Water -/
Figure 2-9. Typical Junction box.
Another type of tank used to treat aqueous wastes is an
air stripper (Figure 2-11), which may be a spray tower,
packed column, or simply an aerated tank. It is most com-
monly used to remove parts per million or lower levels of
volatiles from dilute aqueous wastes. Many air strippers with
lower emissions simply are vented directly to the atmosphere,
while others are controlled by carbon adsorption or incinera-
tion if organic concentrations warrant Condensers on air
strippers are generally ineffective because of low vapor phase
concentrations and high volumetric flow rates.
Emissions
Emissions
^
Forebay
Separator
Jk*3£M35WW/.S2
— *• Water
— »• Sludge
Otly W ^tewater
Figure 2-10. Oil-water separator.
Steam stripping also is used to treat aqueous wastes with
concentrations on the order of hundreds of parts per million or
higher. Steam is injected directly into the wastewater, the
overhead vapors are condensed, organics are separated from
the condensed water, and the decanted water is returned to the
feed stream. Emissions occur from the vent on the condenser/
decanter and from collection tank vents.
A schematic of an actual steam stripping system is shown
in Figure 2-12 and illustrates the use of a heat exchanger to
preheat the feed (to recover energy) and to cool the bottoms
stream from the stripper before additional wastewater treat-
ment. This particular system has a high level of organic
recovery because both a primary arid much colder secondary
condenser are used. Emission control should be excellent
because noncondensibles are vented to a vapor incinerator.
For continuous steam strippers, pretreatment (Figure 2-
13) may sometimes be required to adjust pH or to remove
solids, which can foul the column packing or trays and cause
plugging problems. Any separate organic phase that can be
decanted from the wastewater is removed prior to stripping.
Sludges
Fixation is another process trial is often performed in
tanks to solidify or stabilize sludges. The basic steps include
mixing in a fixative agent, such as lime or fly ash, curing to
allow solidification, and disposal. Mxing occurs most often
in tanks, containers, or pug mills, w hich are relatively easy to
enclose to control emissions. About half of the hazardous
waste that is solidified is cured in tanks or containers, and the
other half is cured in large open sources such as trenches or
landfills.
Most of the volatiles are emitted during mixing when
agitation is provided while adding the fixative agent. Exother-
mic reactions produce heat and increase volatilization, as in
the addition of quick lime or calcium oxide to aqueous slud-
ges. These emissions can be controlled by installing covers or
enclosures that are vented to a control device.
16
-------
Overhead Vapors
Control Device
Feed
Vent
J—
Storage
and
Feed Tank
Pump
A A A A
Packed
Column
Effluent
Figure 2-11. Schematic diagram of an air stripping system.
Another common process used for managing sludges is
dewatering, which is performed by various types of filter
presses, rotary vacuum filters, and centrifugal filters. A plate-
and-frame press is an assembly of alternate solid plates,
which are grooved or perforated to permit drainage, and
hollow frames, in which the dewatered sludge collects during
filtration. A filter medium, usually a fabric, covers both faces
of each plate. As the slurry passes through the filter fabric to
the plates, a cake of solids slowly builds up. The filtration
continues until the pressure drop across the filter reaches a
preset limit. The plates are then separated and the cake drops
from the filter press into a collection bin under the press.
The belt filter press (Figure 2-14) squeezes the sludge
between two systems of belts. Sludge is fed onto the lower
belt, and, as the belt moves into the press, the upper belt meets
it and squeezes the sludge. The filtrate squeezed from the
sludge is usually collected in a sump under the filter and
removed for further treatment or discharge. Solids are scraped
off the belts as they separate and collect in a bin or are taken
by conveyor to a storage or disposal area. As the belts
continue their rotation, they are usually cleaned by being
Liquid Distributor
Air
Stripper
y
Vented
* Air
Control Device Residue
(e.g., Spent Carbon)
•Air
passed through a belt washing system of high-pressure spray
nozzles.
Other types of dewatering units are rotary in nature and
use a vacuum, gravity, or centrifugal force to remove water
from the sludge. For larger scale operations, sludge is scraped
from the unit continuously and discharged through a chute to
a container or conveyor belt
These dewatering devices are not usually enclosed sys-
tems and provide several opportunities for volatile organics to
be emitted. For the plate-and-frame press, emissions occur
when the press is opened to remove and transport the accumu-
lated sludge. During filtration, a small amount of liquid may
leak from the press and accumulate in the drip pan under-
neath. The belt press provides a moving exposed surface area
that facilitates drying and evaporation of volatiles. The filtrate
drains freely and is often collected in an open sump. Both the
filtrate and sludge are sources of emissions. Similarly, the
sludge and filtrate handling systems for rotary vacuum and
centrifugal filters are emission sources for any volatiles that
are present in the original slurry. In addition, the vacuum
pump may discharge volatiles. Emissions from dewatering
devices can be controlled by building an enclosure around the
unit and venting it to a control device.
Condenser;
ToWWT
Waste
Water to
Feed
Tank
EDC
Additives Vent
Wastewater
Decanted Water
Organics
Sludge
Figure 2-12. Steam stripper for ethylene dichloride/vlnyi
chloride. Figure 2-13. Preliminary treatment prior to stripping.
17
-------
Press Belt
Sludge
Loading
Drive
Rollers
Figure 2-14. Belt filter press.
Thin-film evaporators (TEEs) (Figure 2-15) are also used
to treat sludges. The primary advantage of this treatment
technique is that it can remove volatiles from viscous sludges
and slurries. A thin layer of waste is spread over a moving or
wiped surface that is heated to volatilize organics. Emissions
To Condenser/
' Decanter
Heating
Medium
Modular
Heating
Bodies
Product Outlet
Figure 2-15. Row path of thin-film evaporator.
occur from vents on condensers, decanters, and collection
tanks, or from the vacuum system if one is used.
The vertical thin-film evaporator looks like a distillation
column. In the TFE, the vapors with volatile organics are
removed overhead to a condenser, and the treated waste is
discharged from the bottom.
Ancillary Equipment
The ancillary equipment associated with tank systems
includes pumps, valves, pressure-relief devices, compressors,
sampling connections, and open-ended lines, which can be-
come emission sources when they leak. Controls include dual
mechanical seals with a barrier fluid (for pumps and compres-
sors), sealless pumps, diaphragm or sealed-bellows valves,
rupture disks for pressure-relief devices, closed-loop sam-
pling, and caps for open-ended lines. In addition to the equip-
ment controls for these types of sources, emissions can be
controlled by establishing a leak detection and repair (LD AR)
program. This program includes surveying these components
for leaks, using a portable organic vapor detector to locate
leaks, and making repairs, adjustments, or replacements as
needed.
Containers
Containers are defined as any portable device in which a
material is stored, transported, treated, disposed of, or other-
wise handled. Examples of typical containers are drums,
dumpsters or roll-off bins, and tank trucks. Emissions occur
from loading these containers, from uncovered containers
during storage or transport, and from spills.
Drums can be sources of emissions from the evaporation
of leaks and spills, and poor housekeeping practices can make
spill detection and cleanup difficult If the drums are well
maintained on a diked pad, emissions from spills or ruptures
can be identified by routine inspection procedures and promptly
cleaned up. Dumpsters or roll-off bins can be a source of
emissions if they are left uncovered with the surface of the
waste exposed to the atmosphere.
Emissions from containers (Figure 2-16) occur when they
are loaded, and emissions are greatest when splash filling is
18
-------
Splash Loading
(Tends to Saturate Vapors)
Vapor Emissions
Rll Pipe
Hatch Cover
Cargo Tank
Product/
Figure 2-16. Splash loading vs. submerged loading.
Submerged Loading
Vapor Emissions
Fill Pipe
Vapors
J
Hatch Cover
, Cargo Tank
Product •
used. When splash filling, the vapors displaced from the
container by loading can quickly become saturated with vola-
tiles from the splashing. Submerged fill uses an influent pipe
that is below the surface, which reduces splashing and the
degree of saturation of the displaced vapors. A study of
submerged filling of tank trucks indicated that emissions were
reduced by 65 percent relative to splash filling. Other basic
controls for containers include using simple covers during
storage or transport and routine housekeeping practices with
daily inspections and prompt cleanup of spills.
Land Disposal Sources
Landfills, wastepiles, and land treatment are the sources
expected to be most directly affected by the LDR. These are
open area sources from which the volatile organic compounds
are emitted fairly quickly, and the emissions can be controlled
by covers and enclosures. However, the technologies de-
scribed under LDR will likely take care of the volatile organ-
ics, and in the end they should not be significant sources of
emissions.
A land treatment facility is defined as a facility at which
hazardous waste is applied onto or incorporated into the soil
surface; such facilities are disposal facilities if the waste will
remain after closure. Land treatment is also known as land
farming, land application, land spreading, and soil incorpora-
tion. Volatiles are rapidly emitted from the surface of land-
treated waste (Figure 2-17). Over time, volatiles diffuse through
the waste to the surface, where they are swept away by the
wind.
In land treatment, the waste can be applied to the soil and
mixed by tilling, or the wastes may be sprayed directly onto
the soil and subsequently mixed with the soil by tilling.
Volatiles are rapidly removed from the waste during spraying.
Landfills are composed of active and covered cells. Wastes
are often segregated based on waste compatibility and com-
paction requirements. The wastes are then covered with a
layer of soil and compacted, and another layer of waste is
added or a new cell is started. If any volatiles are left in the
waste when it finally reaches the landfill, they are rapidly
emitted from the surface of exposed waste in active cells.
After covering and compacting, emissions occur by diffusion,
barometric pumping, and gas venting (Figure 2-18).
Wastepiles are defined as noncontainerized accumula-
tions of solid, nonflowing hazardous waste used for treatment
or storage. The emission mechanisms for wastepiles are simi-
lar to those for land treatment: rapid volatilization from the
exposed surface followed by mass transfer through the waste.
Models have been developed for exposed soil surfaces
such as land treatment and wastepiles and for covered land-
fills. In the model for exposed soil surfaces that contain
organics, volatiles in the oil and water are assumed to be in
equilibrium with air in the void spaces. Some organics may be
adsorbed onto the soil particles, and, in some cases, biodegra-
dation may destroy the organics. Emissions occur by diffusion
to the surface, where organics are removed by the wind. For
the covered portion of landfills, the modeling includes diffu-
sion through the cap and losses from barometric pumping,
which is caused by changes in ambient pressure.
These land disposal sources can be controlled by install-
ing a flexible membrane cover, enclosing the source in a rigid
structure, or using an air-supported structure as discussed
earlier for surface impoundments. A better emission control is
not to place wastes containing volatiles in these sources (for
example, treat the wastes to remove the organics before
disposal).
Emission Controls
Several air pollution control devices can be applied to
many of the sources that have been discussed once they are
covered or enclosed and vented. The traditional ones that are
discussed briefly here are carbon adsorption, condensation,
absorption, and vapor combustion.
Carbon Adsorption
In adsorption, organics are selectively collected on the
surface of a porous solid. Activated carbon is a common
adsorbent because of its high internal surface area: 1 gram of
carbon can have a surface area equal to that of a football field
and can typically adsorb up to half its weight in organics. The
adsorber will remove essentially all of the target volatiles
19
-------
Wind
Volatilization
Diffusion
Through Pores
Adsorption Onto Soil Particles
Absorption into Oil and Water
Figure 2-17. Land treatment emission mechanisms.
from the vented vapors until breakthrough, which is when the
volatiles are first detected in the cleaned vapor leaving the
bed. Carbon adsorbers can achieve control efficiencies of at
least 95 percent, and control levels of 97 to 99 percent have
been demonstrated in many applications. The two common
types of adsorbers are carbon canisters and regenerable fixed
beds.
Carbon canisters (Figure 2-19) are used for low vent
flows, usually less than 100 ft?/min, and are not regenerated
onsite. They are usually discarded or returned to the supplier.
The canisters are fairly compact units and can easily be
removed and fresh canisters installed. Fixed-bed carbon
adsorbers that can be regenerated (Figure 2-20) are used for
controlling continuous vent streams with flows exceeding
100,000 ftVmin and can handle a wide range of organic
Diffusion through the Cap
concentrations. A common procedure is to have dual beds
with one desorbing while the other is adsorbing.
The carbon capacity for organics is affected by the con-
centration of organics in the vapor. Carbon manufacturers
generally have equilibrium data for specific compounds and
then* specific carbons. The bed design is important and must
be deep enough to prevent rapid breakthrough, yet not so deep
as to cause excessive pressure drop. The flow rate is important
in the bed design and in determining carbon capacity require-
ments. Humidity has an adverse effect when water occupies
some of the adsorption sites. For a relative humidity of 50
percent or more, dehumidification or dilution may be neces-
Convective Loss from
Barometric Pumping through
h the Vent.
Figure 2-18. Emissions from a closed landfill.
20
-------
• For Vent Flows Less Than 100 CFM
Cannot Be Regenerated in Canister
Activated Carbon
Support Material
Condensation
Condensers work by cooling the vented vapors to the dew
point and removing the organics as a liquid. The efficiency of
a condenser is determined by the vapor phase concentration of
the specific organics and die condenser temperature. Two
common types of condensers are contact condensers and
surface condensers.
The contact condenser (Figure 2-21) is cheap and effi-
cient. However, the cooling liquid that directly contacts the
vented vapors can present a disposal problem. For example, if
the coolant is water that is sent to wastewater treatment, the
volatiles may be emitted in open tanks. The shell and tube
condenser (Figure 2-22) does not allow contact between die
vented vapors and the cooling medium. In this type of con-
denser, a concentrated organic liquid can be recovered for
recycle or other use.
Absorption
In absorption, the organics in the vent gas are dissolved in
a liquid (Figure 2-23). The contact between the absorbing
Figure 2-19. Carbon canisters.
sary to lower the relative humidity. The bed's operating
temperature affects capacity, and some compounds such as
aldehydes and ketones may generate heat in adsorbers. For
these special cases, some means of removing the excess heat
may be necessary.
For effective emission control by adsorption, one of two
actions is necessary: either to monitor for breakthrough or to
replace die carbon periodically before breakthrough occurs. In
addition, any emissions from die disposal or regeneration of
die carbon should be controlled. Controlling emissions from a
vent stream is of little value if die collected organics are
emitted later in die wastewater treatment associated widi
regeneration.
Vapor Outlet
Water Inlet
i L_ : i
Vapor Inlet
Distribution Tray
Liquid Level
Liquid Outlet (Water and VOCs)
Figure 2-21. Schematic diagram of a contact condenser.
Vapors
Open
Closed
Steam
Adsorbing
Desorbing
->• Vent
to Atmosphere
To Condenser
and Separator
Figure 2-20. Two-stage adsorption system.
liquid and die vent gas is accomplished in spray towers,
scrubbers, or packed or plate columns. Some common sol-
vents diat may be useful for volatile organics include water,
mineral oils, or odier nonvolatile petroleum oils. Absorption
efficiencies of 60 to 96 percent have been reported for organ-
ics. For example, mediylene chloride removal from vented
vapors has been measured at 87 percent using water as die
absorbing liquid.
The material removed from die absorber may present a
disposal or separation problem. For example, organics must
be removed from die water or nonvolatile oil without losing
diem as emissions during die solvent recovery or treatment
process.
Vapor Combustion
Vapor combustion is anodier control technique for vented
vapors. The destruction of organics can be accomplished in
flares, thermal oxidizers, such as incinerators, boilers, or
process heaters, and in catalytic oxidizers.
21
-------
Coolant Inlet
Vapor Outlet
Vapor Inlet
Coding Tower or
Refrigeration Unit
Coolant Outlet
Condensed VOC
(to Decanter or Receiving Tank)
Figure 2-22. Schematic diagram of a shell-and-tube surface condenser.
Flares are an open combustion process in which the
oxygen is supplied by the air surrounding the flame. Flares are
operated either at ground level (usually with enclosed mul-
tiple burner heads) or they are elevated. Elevated flares often
use steam injection to improve combustion by increasing
mixing or turbulence and pulling in additional combustion air.
Properly operated flares can achieve destruction efficiencies
of at least 98 percent Figure 2-24 is a schematic of the basic
components of a flare system. The EPA has developed regula-
tions for the design and operation of flares that include tip exit
velocities for different types of flares and different gas stream
heating values.
Thermal vapor incinerators can also achieve destruction
efficiencies of at least 98 percent if the conditions of an
adequately high temperature, good mixing, sufficient oxygen,
and an adequate residence time are met. These vapor incinera-
tors can be designed to handle vent rates of 200 to 500,000
cfm. An auxiliary fuel may be required to maintain the com-
bustion conditions if the vent gas hzis less than 50 Btu/scf.
Figure 2-25 shows the components of a vapor incinerator. A
heat recovery unit, such as a steam generator, may be used to
recover some of the energy from a thermal incinerator.
Catalytic incinerators provide oxidation at temperatures
lower than those required by thermal incinerators. Design
considerations are important because the catalyst may be
adversely affected by high temperatures, high concentrations
of organics, fouling from particulate matter or polymers, and
deactivation by halogens or certain metals. The basic compo-
nents of a catalytic oxidizer (Figure 2-26) are similar to those
of a thermal unit except that a catalyst bed is used. The energy
requirements of a catalytic oxidizer are lower than those of a
thermal unit because of the lower operating temperatures.
»• Cleaned Gas Out 1o
Final Control Device
Absorbing
Liquid In
Organic Laden
Gas In
Absorbing Liquid with
Organics Out
To Disposal or Organic Solvent Recovery
Figure 2-23. Packed tower for gas absorption.
22
-------
Steam
Nozzles
Gas
Barriers
Helps Prevent Flashback
Gas Collection Header
and
Transfer Line
Knock-out
Drum
Stream
• Line
- Ignition
Device
Air Line
Gas Line
Drain
Figure 2-24. Steam-assisted elevated flare system.
The organics in vented vapors can also be destroyed with
a high level of efficiency in boilers or process heaters. In these
devices, vapors with halogens or sulfur are avoided because of
potential corrosion problems. These devices recover the heat-
ing value of the vent stream, and they offer the advantage of
using existing equipment to control emissions.
Organic Removal
Organic removal or pretreatment is a control option that
is applicable to a variety of waste types. These processes
include steam or air stripping, thin-film evaporation, solvent
extraction, and distillation. These processes are capable of
removing essentially all of the highly volatile compounds
from the waste. The removal of the volatiles near the point of
generation can avoid the need to install controls on subse-
quent process units and may facilitate recycling the recovered
organics back to the process.
The control efficiency that can be obtained by organic
removal depends on many factors, such as the percent re-
moved from the waste, the emissions from the removal sys-
tem, and the uncontrolled emissions from treatment units
before the removal device was installed. Generally, overall
control efficiencies of 98 to over 99 percent can be achieved.
Waste Incineration
Waste incineration is also an emission control option that
can be used instead of processing the waste in units with a
high emission potential. This technology has been identified
as an alternative to land disposal in the development of the
land disposal restrictions for certain wastes. Destruction effi-
ciencies of 99.99 percent or higher have been demonstrated in
properly operated waste incinerators.
Summary
In summary, tanks and surface impoundments are the
major sources of organic air emissions at hazardous waste
treatment, storage, and disposal facilities. Based on work
performed in the development of the benzene waste NESHAP,
wastewater systems are a major source of benzene emissions
from wastes that contain benzene.
Emissions occur from the surface of open area sources,
and high percentages of the volatiles are lost as emissions in
these sources. For enclosed sources, die displacement of
vapor containing volatiles from the enclosed vapor space is
the emission mechanism. For both types of sources, heating or
23
-------
Waste Gas
Stack
Auxiliary
FueJ Burner
(Discrete)
Air
Mixing
Section
Combustion
Section
Optional
Heat
Recovery
Figure 2-25. Thermal Incinerator.
aeration increases emissions. Emissions also occur from the
evaporation of leaks and spills.
Emission models have been developed for open area
sources, including both the liquid surface of impoundments
and tanks and the solid surfaces associated with land treat-
ment and landfills. Both types of models can account for the
biodegradation of specific compounds, and the effect of tur-
bulence from agitation can be included for liquid surfaces. For
enclosed sources, models are available to estimate the vapor
displacement rate and the concentration of volatiles in the
vapor.
For emission control, open area sources and containers
can be covered or enclosed. Control devices can be installed
to collect and remove organics from vented vapors, which is
especially important if the sources are heated or aerated.
Organic removal by pretreatment and waste incineration are
also emission control options, and their use may preclude the
need to apply covers or control devices to subsequent treat-
ment units. Simple work practices, such as leak detection and
repair or inspections and cleanup of spills, help to control
emissions from equipment leaks and spills. Pumps and valves
that are designed not to leak offer Jinother potential control
option for these sources.
Catalyst Bed
Auxiliary
Fuel Burners
Waste Gas
Optional
Heat Recovery
Mixing Chamber
Figure 2-26. Catalytic oxidlzer.
24
-------
Bibliography
U.S. Environmental Protection Agency, CERI. "Handbook:
Control Technologies for Hazardous Air Pollutants." EPA/
625/6-86/014. NTIS PB91-228809/AS. Cincinnati, OH.
September 1986.
U.S. Environmental Protection Agency, Control Technology
Center. "Industrial Wastewater Volatile Organic Com-
pound Emissions—Background Information for BACT/
LAER Determinations." EPA-450/3-90-004. January
1990.
U.S. Environmental Protection Agency, OAQPS. "Alterna-
tive Control Technology Document—Organic Waste Pro-
cess Vents." EPA-450/3-91-007. December 1990.
U.S. Environmental Protection Agency, OAQPS. "Hazard-
ous Waste Treatment, Storage, and Disposal Facilities
(TSDF)—Air Emission Models." EPA-450/3-87-026. No-
vember 1989.
U.S. Environmental Protection Agency, OAQPS, "Hazard-
ous Waste Treatment, Storage, and Disposal Facilities
(TSDF)—Background Information for Promulgated Or-
ganic Emission Standards for Process Vents and Equip-
ment Leaks." EPA-450/3-89-009, July 1990.
U.S. Environmental Protection Agency, OAQPS. "Hazard-
ous Waste TSDF—Background Information Document
for Proposed RCRA Air Emission Standards." EPA-450/
3-89-23. (Will be available to the public upon proposal of
the standard.)
U.S. Environmental Protection Agency, OAQPS. "Hazard-
ous Waste TSDF—Technical Guidance Document for
RCRA Air Emission Standards for Process Vents and
Equipment Leaks." EPA-450/3-89-21. July 1990.
U.S. Environmental Protection Agency, ORD/HWERL. "Pre-
liminary Assessment of Hazardous Waste Pretreatment
as an Air Pollution Control Technique." EPA-600/2-86-
028. NTIS PB86-172095/AS. March 1986.
U.S. Environmental Protection Agency, OAQPS. "VOC
Emissions from Petroleum Refinery Wastewater Sys-
tems—Background Information for Proposed Standards."
EPA-450/3-85-001a. February 1985.
Questions and Answers
Question—Whatis the difference in thecombustion of gaseous
emissions at 95 to 98 percent efficiency versus the
combustionof hazardous waste at 99.99percentefficiency?
Answer—Vapor incinerators are often used on vapor streams
thathave relatively low concentrations. EPA studies indicate
that destruction efficiencies on the order of 98 percent or
higher can be achieved on these vapor streams. For vapor
streams with very low concentrations, the destruction
efficiency may be limited by a minimum outlet
concentration of 20 ppm.
The destruction andremoval efficiency (DRE) for hazardous
waste combustion is based on the principal organic
hazardous constituents. These compounds are present in
relatively high concentrations, and the measured DRE is
often limited by detection limits in the exhaust.
Question—How significant are equipment leaks as sources of
emissions?
Answer—The uncontrolled emissions can be as significant as
those from open area sources, especially when the facility
has a large number of equipment items (such as pumps,
valves, and flanges) that handle volatile organic emissions.
Question—Are emissions from landfills, land treatment, and
wastepiles significant, and will these sources be regulated
for organic emissions?
Answer—Currently, no plans to regulate these sources under
Section 3004(n) of RCRA exist Our available data and
consideration of the effects of the land disposal restrictions
suggest that these operations are not significant sources of
organic emissions.
Question—When carbon is used for emission control, what
happens to the organics that are removed when the carbon
is regenerated?
Answer—The fate of the organics depends on the regeneration
process. If the regeneration is performed in a furnace, the
organics in the gases and vapors removed from the carbon
usually are destroyed by thermal oxidation. If steam is used
for regeneration, the organics are either recovered by
condensation, emitted through the condenser vent, or
emitted from the wastewater (condensed steam from
regeneration) when it is treated.
Question—Are primary condensers part of the production unit
or are they control devices? Condensers are efficient from
primary control, but often do not get high efficiencies as an
emission control. Is EPA promoting then- use?
Answer—Primary condensers are part of the production unit
and are not considered as a control device to meet the
standards. For example, in many recovery operations,
volatile components are separated in the vapor phase and
then recovered by condensation in the primary condenser.
The EPA is not promoting the use of condensers; most of
the rules require that thecondenser be designedandoperated
to achieve a control efficiency of at least 95 percent.
Consequently, condensers may not be acceptable controls
in many applications, such as the control of vapor streams
with very low concentrations or streams that would require
unreasonably low temperatures to achieve 95 percent
control.
25
-------
-------
Chapter 3
Process Vents Standards
Subpart AA
Abstract
The objective of this presentation on the RCRA pro-
cess vent rules is to provide a basic understanding of the
new RCRA air emission standards for process vents so
that those persons required to comply with, implement, or
enforce the rules can do so effectively and in a timely
manner. The presentation clearly explains the process
vent rule applicability criteria, which include facility au-
thorization under RCRA, hazardous waste management
unit type, and waste organic concentration. Technical
requirements for emission controls and the facility "bubble"
concept for emission rate limits are explained. Record-
keeping and reporting requirements are discussed also.
The process vent standards in 40 CFR 264 and 265,
Subpart AA, limit organic air emissions at hazardous
waste treatment, storage, and disposal facilities (TSDF)
requiring a permit under Subtitle C of the Resource Con-
servation and Recovery Act (RCRA). The standards were
promulgated on June 21,1990 (55 FR 25454), under the
authority of Section 3004(n) of the Hazardous and Solid
Waste Amendments (HSWA) to the RCRA. The Subpart
AA standards are applicable to process vents associated
with distillation, fractionation, thin-film evaporation, sol-
vent extraction, and air and steam stripping operations
that manage hazardous wastes with 10 parts per million
by weight (ppmw) or greater total organic concentration.
The RCRA air rules for process vents require that owners/
operators of TSDFs subject to the provisions of Subpart
AA: (1) reduce total organic emissions from aU affected
process vents at the facility to below 1.4 kg/h (3 Ib/h) and
2.8 Mg/yr (3.1 ton/yr), or (2) install and operate a control
device(s) that reduces total organic emissions from all
affected process vents at the facility by 95 weight percent
The process vent rules do not require use of any specific
types of equipment or add-on control devices. Condensers,
carbon adsorbers, incinerators, and flares are demon-
strated emission control technologies for the regulated
processes, although the choice of control is not limited to
these. To ensure that control devices perform according to
their design, the rules for process vents require that spe-
cific control device operating parameters be monitored
continuously and the monitoring information be recorded
in the facility operating record.
Process Vents
This chapter covers the organic air emission standards for
process vents. These rules were promulgated on June 21,
1990. The purpose of the chapter is to answer some of the
most common questions the U.S. Environmental Protection
Agency (EPA) has received on the rules.
This chapter should answer the following questions (Table
3-1): "Who is affected by the rule, why did EPA develop the
rule, and how many facilities are subject to the rule?" In
addition, details of the regulation including types of regulated
units, the effective date, control device requirements,
recordkeeping, and reporting will be discussed.
Table 3-1. Questions on Details
What units are regulated?
How does the regulation work?
When do the regulations become effective?
What are the requirements for control devices?
What records must be maintained?
What reports must be filed?
Who is affected? On the broadest level, anyone who has a
facility subject to Part 270 of the Resource, Conservation, and
Recovery Act (RCRA). That covers anyone with a Subtitle C
facility, whether the facility has a final permit or is still in
interim status. In promulgating this rule, EPA modified Sec-
tion 261.6 of the RCRA regulations and brought in previously
exempt recycling units at RCRA-permitted facilities. If you
have a RCRA permit and you have a recycling unit that up to
this point has not been subject to any RCRA rules, it may now
be subject to the RCRA air rules, Subparts AA and BB.
Six types of unit operations are coveted by the rule (Table
3-2): steam strippers, distillation, fractionation, thin-film evapo-
ration, solvent extraction, and air strippers. Unless the unit
involves one of these six types of unit operations, it is not
regulated by Subpart AA.
Other than recycling, all RCRA exemptions remain in
effect. Production units are not regulated by RCRA and are
not affected by this rule (40 CFR 261.4(c)). The wastewater
treatment exemption applies to units that are regulated under
27
-------
Tabte 3-2. Unite Affected
Overhead
Vapors
Steam strippers
Distillation
Fractionatfon
Thin-film evaporation
Solvent extraction
Air strippers
the Clean Water Act (CWA) (40 CFR 264.1(g)(6),
265.1(c)(10), and 270.1(c)(2)(v)). Subtitle D or municipal
waste units are not covered under these rules. Units handling
domestic sewage are exempted from the rules because sewage
is not considered a solid waste (40 CER 261.4(a)(l)). Closed-
loop reclamation refers to another exclusion from die solid
waste definition that is presented in 40 CFR 261.4(a)(8) of the
RCRA rules. Secondary materials that are being reclaimed in
accordance with the RCRA rule are not considered solid
waste and therefore are not subject to RCRA. Section 261.4 is
specific as to what is considered a closed-loop reclamation:
the reclamation process must be connected directly by piping
to the production process, only tank storage is allowed, the
materials have to be reclaimed within 12 months, and recla-
mation cannot involve combustion processes. A process that
qualifies for this closed-loop reclamation exclusion is not
regulated by the Subpart AA rules discussed here.
The applicability discussion started at the facility level,
moved to the process level, and is now at the vent level.
Subpart AA is a waste-based rule, and the waste must contain
10 ppm or greater total organics by weight before an indi-
vidual unit must be controlled under this rule. The 10 ppmw
must be determined on a time-weighted annual average basis,
which means that, at some point in the year, greater than 10
ppmw waste could be managed in the unit and still the unit
would not be affected by the rule if the waste managed in the
unit had an organic concentration of less than 10 ppmw on a
time-weighted annual average basis. In addition, emissions do
not have to be vented from the affected unit If the emissions
arc vented through a tank that is associated with the unit, the
emissions are still covered by this rule.'Typical associated
tanks with affected process vents include condensers, hot
wells, and distillate receivers.
Example 1 (Figure 3-1), air stripping, is one of the six
unit operations covered by the rule. If the waste going into this
air stripper is greater than 10 ppmw in organic concentration
on a time-weighted annual average basis, then the overhead
vapors from this air stripper would be covered by the rule. The
tank that sits in front of the air stripper, the feed tank, is not
regulated by the process vent rule. The emissions from this
tank are a result of the breathing and working losses.
Example 2, steam stripping, is another one of the six unit
operations covered by the rule (Figure 3-2). In this case, the
emissions pass through a condenser and are vented through a
distillate receiver. This distillate receiver is considered a tank
associated with the steam stripper and therefore the emissions
arc regulated under the rule. The other three tanks, the accu-
mulator tank, the effluent storage tank, and the feed tank, are
similar to the feed tank in the first example. Emissions from
these three tanks are not regulated by the process vent rule. If
you need to get a better understanding of which vents are
Feed
Vapors
Waste
In
S.
Effluent
Out
Figure 3-1. Example 1—air stripping,,
Air In
covered under the rules, the process vent case study is very
helpful.
Subpart AA was developed to protect human health and
the environment In addition, as mentioned previously, EPA
developed this rule in recognition of the fact that the Office of
-Solid Waste (OSW) was also developing rules on land dis-
posal restrictions and that air emissions would need to be
controlled from some of the technologies used to comply with
the land disposal restrictions rule.
The number of units in the United States is shown in
Figure 3-3. These data were collected by the OSW in 1987.
Batch distillation is the most common, with 185 units, and the
numbers decrease to only 10 air strippers shown as regulated
under RCRA in 1986. Again, the rule covers recycling units
that are located at facilities with a RCRA permit so these
numbers from 1986 will increase as previously unregulated
units are brought into the RCRA system. The annual emis-
sions for three different size model plants is presented in
Figure 3-4. In the development of the rule, EPA looked at
three different size facilities based on annual operating hours
Condenser
Vapors
Feed Tank
Vapors
t
F-—-*|| Effluent
\ Jl Storage
Figure 3-2. Example 2—steam stripping.
Vapors
Accumulator
Tank
28
-------
200
185
Batch Fraction- Thin-film
Distillation ation Evapor-
ation
Figure 3-3. Number of units.
10
•• . •
Solvent steam Air
Extrac- Strippers Strippers
tion
Source: 1987 TSDR Survey
and the size of the units. With six different operations covered
by the rule, quite a range of emissions exists. For a large
facility, emissions range from about 1 ton per year up to
slightly more than 20 tons per year. Medium facilities range
from around 1/2 ton per year up to 5-1/2 tons per year. Small
facilities, which are primarily batch distillation units, all have
less than 1 ton per year of emissions.
The five steps involved in how the regulation works at a
single facility are listed in Table 3-3.
The first step is to identify all the units that fall under the
rule. Six types of unit operations are covered, and the units
must be treating a hazardous waste with an organic concentra-
tion of 10 ppmw or greater on a time-weighted annual basis.
Once a unit is identified as falling under the rule, the owner/
operator must determine the maximum hourly and annual
emission rates from the vents. The rule specifies methods that
can be used for direct measurement, such as Method 18 for
organic concentration and Method 2 for velocity and volumet-
ric flow rate. In addition, the rule has provisions for use of
"knowledge" to determine emission rates. If you have previ-
ously tested the stack on the process vent and can certify that
the operation and the waste have not changed, then the previ-
ous test results would be acceptable. In some cases, the
manufacturer may be able to certify emission rates on certain
units.
Once a maximum hourly and annual emission rate for
each vent has been determined, the individual rates must be
summed to get a facility rate. The total facility process vent
emissions rate must be compared to the limits of 3 Ib/h and 3.1
ton/yr. If the facility is over either limit, the owner/operator
must either reduce emissions down to the limit or reduce total
facility process vent emissions by 95 percent. The rule speci-
fies that the reduction must be obtained by using a control
device.
In Example 3, shown in Figures 3-5, 3-6, and 3-7, three
process vents have been identified; the facility emission rate is
obtained by summing the individual emission rates. In this
case, the three emission rates are 10,1, and 55, for a total of 66
ton/yr. To reach compliance with the rule, the facility must
either bring emissions below the emission rate limit or reduce
the total by 95 percent. In this case, a 95 percent reduction
works out to be 3.3 ton/yr, which is slightly greater than the
3.1-ton/yr emission rate limit. The facility can reach compli-
ance by achieving 95 percent control on each of the three
vents. The facility could use three different control devices, or
it could tie all three into a single control device that would
achieve 95 percent. A second option shown here involves the
facility providing 88 percent control on Process Vent #1,
leaving the second vent uncontrolled, and achieving an emis-
sion reduction of 98 percent on the largest emitting vent, #3.
25.0 -i
20.0 •
15.0 •
10.0 -
5.0 •
0.0 •
«
1 1 . J_ I
Large Facility Medium Facility Small Facility
Model Plants - Annual Emissions Estimates
Figure 3-4. Annual emissions from a typical facility.
29
-------
Tabta 3-3. How the Regulations Work
Identify affected process vents
Determine emission rates
Sum Individual rates
Compare to emission rate limits
Reduce emissions below limits or 95%
One additional point: certain control devices have the perfor-
mance standards in the rules. The performance standard for
combustion devices is 95 percent destruction efficiency. A
facility using a combustion device on Vent #1 would not be in
compliance with a control efficiency of 88 percent
The rules became effective December 21, 1990. How-
ever, the compliance date depends on the classification of the
facility. Interim status facilities have up to 18 months after the
effective date to install control equipment. The 18 months is
not a blanket extension; facilities will need to submit an
implementation schedule to the permit writer for approval.
Facilities that already have a final permit are shielded
from the Phase I air standards; this means that they do not
have to comply with the standards until their permit is reis-
sued. The different situations that occur under the RCRA
permitting program are discussed in the RCRA implementa-
tion chapters of this workshop.
The rule does not specify the use of a specific control
device. However, there are individual performance require-
ments for certain devices. In addition, there is a provision that
equipment must be properly designed, operated, and main-
tained and continuously monitored. The regulation specifies
what parameters must be monitored for particular control
devices. As an example, if you are using a vapor incinerator,
you have to monitor the temperature in the combustion cham-
ber downstream of the combustion zone. If you are using a
catalytic incinerator, you have to monitor temperature both at
the inlet and the outlet of the catalyst bed. In addition, the
owner/operator is required to do a duly check of the control
device to ensure proper operation.
Vapor recovery systems include condensers and carbon
adsorbers, and the rule specifies that each device has to
achieve at least 95 weight percent recovery efficiency. The
primary condenser on a distillation column is considered a
primary recovery device rather than a control device and does
not count toward the 95 weight percent reduction. For com-
bustion devices such as incineratoirs, process heaters, and
boilers, the rule requires a destruction efficiency of 95 weight
percent or greater or the use of a combustion device that has a
minimum residence time of hah7 a second at a minimum
temperature of 760°C. In addition, EPA's work on vapor
incinerators determined that, for air streams with low concen-
trations of organics, 95 percent reduction is not always pos-
sible. For those situations, the rule includes an alternative
provision by which you can demonstrate that the incinerator
exhaust concentration has been reduced to 20 ppm by volume
total organics and be in compliance with the process vent
rules.
Flares are another option as a control device. The perfor-
mance requirements for flares specify that they can have no
visible emissions as demonstrated by using Method 22. A
flame must be present at all times, and a heat-sensing monitor-
ing device with continuous recorder to indicate the continuous
ignition of the pilot flame must be usied. In addition, the flare
requirements have specifications for net heating value on the
gas being combusted and the permissible exit velocity.
The owner/operator must inspect readings from each
monitoring device daily, and, if there is a problem, the rules
require that the owner/operator immediately implement cor-
rective measures to get the control device operating correctly
again.
The equipment that connects line process vent to the
control device is called the closed-vent system (Figure 3-8).
The next chapter on equipment leaks will cover leak monitor-
ERFaci.i,y=£ERPvi
ER
FaciIity =
Figure 3-5. Facility bubble for emission rate (ER).
ERpv2 + ERpv3
30
-------
ERFacility= ERPv1 + ERPv2 + ERPv3
ER Facility = 10 + 1 + 55 = 66
Figure 3-6. Example 3—control options for a facility.
ER Facility =66
66(1-.95) =3.3
3.3Mg/yrvs.3.1 Mg/yr
Option 1 - 95% Control on All Three Vents
Options- 88% Control on pv1 and98%
Control on pv3
Figure 3-7. Example 3 (continued)—control options for a facility.
ing required of closed-vent systems. In this figure, emissions
from this process vent pass through the closed vent system to
the control device.
Records must be maintained to demonstrate compliance.
The records must be kept onsite at the facility and consist of
two main types: facility compliance documents and control
device records. For facility compliance documents, records
must be kept of the waste stream determinations, which are
particularly important if you are claiming that a unit is exempt
from controls because it receives waste with an average
concentration less than 10 ppmw. Emission rate determina-
tions, the second type of records, are the stack tests and other
materials that document emissions from a particular unit and
also total emissions from the facility.
Facilities that are installing a control device must keep
the implementation schedule in the operating record. In addi-
tion, design and operational information must be maintained
in the operating record. Control device exceedance records
must also be maintained. The rules specify the conditions that
define an exceedance (i.e., when the control device is not
operating correctly). As an example, an incinerator designed
to operate at 760°C is exceeding the rules when it is operating
at <760°C. Any time the owner/operator finds an exceedance,
the owner/operator must record that exceedance and keep it as
part of the records. In addition, facilities that elect to use
alternative controls must keep additional information regard-
ing the control device onsite.
Facilities with a final permit that incorporates these rules
are required to submit semi-annual reports if any exceedances
31
-------
Closed-vent System
Ducts, pipes, connectors, and
blowers which transport vapors
or gases from equipment to a
control device
Carbon Adsorption System
Haz. Wastes
SlOppmw
Organics?
Figure 3-8. Closed-vent system.
Figure 3-9. Summary—applicability decision tree.
last longer than 24 hours. Note that all exceedances must be
recorded in the operating record. However, only exceedances
that go uncorrected for more than 24 hours must be reported.
A facility with no exceedances during a 6-month period does
not file any report. Interim status facilities are not required to
report.
The rule with an applicability decision tree is summa-
rized in Figure 3-9. The first decision point is a determination
of whether the facility is subject to Subtitle C of RCRA. If so,
are any units affected, i.e., any of the six specific unit opera-
tions that are regulated under rules of RCRA? If so, do these
unite treat hazardous waste with greater than 10 ppmw in the
total organics on a time-weighted annual basis? Finally, are
any of these units exempt under the rules of RCRA? If they
are not exempt units, the rule applies, and the facility must
meet the emission rate limits. The limits require that all
organic emissions from affected process vents be reduced to
below 3 Ib/h and 3.1 ton/yr. As an alternative, the facility can
reduce the total organic emissions from all affected process
vents by 95 percent after the primary recovery.
Bibliography
"Hazardous Waste Treatment, Storage, and Disposal Facili-
ties; Air Emission Standards for Volatile Organics Con-
trol." Federal Register, Vol 52, pp 3748-3770. February
5,1987.
"Hazardous Waste Treatment, Storage, and Disposal Facili-
ties —Organic Air Emission Standards for Process Vents
and Equipment Leaks." Federal Register, Vol 55, pp
25454-25519. June 21,1990.
U.S. Environmental Protection Agency. "Air Stripping of
Contaminated Water Sources - Air Emissions and Con-
trols." Control Technology Center. Research Triangle
Park, NC. Publication No. EPA450/3-87-017. August
1987.
U.S. Environmental Protection Agency. "Distillation Opera-
tions in Synthetic Organic Chemicd Manufacturing-Back-
ground Information for Proposed Standards." EPA Publi-
cation No. EPA-450/3-83-005a. December 1983.
U.S. Environmental Protection Agency, Air Pollution Train-
ing Institute, RTP, NC 27711. "AITI Course 415 Control
of Gaseous Emissions." EPA-450/2-81-005. December
1981.
U.S. Environmental Protection Agency, Office of Air Qual-
ity Planning and Standards. "Alternative Control Tech-
nology Document - Organic Wastes Process Vents." To be
published in December 1990.
32
-------
U.S. Environmental Protection Agency, Office of Air Qual-
ity Planning and Standards. "Hazardous Waste Treat-
ment, Storage, and Disposal Facilities (TSDF) — Back-
ground Information for Promulgated Organic Emission
Standards for Process Vents and Equipment Leaks." EPA-
450/3-89-009, July 1990.
U.S. Environmental Protection Agency, Office of Air Qual-
ity Planning and Standards. "Hazardous Waste TSDF -
Technical Guidance Document for RCRA Air Emission
Standards for Process Vents and Equipment Leaks." EPA-
450/3-89-21. July 1990.
U.S. Environmental Protection Agency, Office of Air Qual-
ity Planning and Standards. "OAQPS Control Cost
Manual, 4th Edition." EPA-450/3-90-006. Research Tri-
angle Park, NC 27711. January 1990.
U.S. Environmental Protection Agency, Office of Air Qual-
ity Planning and Standards. "RCRA TSDF Air Emissions
- Background Technical Memoranda for Proposed Stan-
dards." EPA-450/3-86-009. October 1990.
U.S. Environmental Protection Agency, Office of Research
and Development, Hazardous Waste Engineering Re-
search Laboratory. "Air Strippers and Their Emissions
Control at Superfund Sites." Publication No. EPA-600/
D-88-153, NTIS PB88-239082. Cincinnati, OH. August
1988.
U.S. Environmental Protection Agency, Office of Research
and Development, Hazardous Waste Engineering Re-
search Laboratory. "Preliminary Assessment of Hazard-
ous Waste Pretreatment as an Air Pollution Control Tech-
nique." Publication No. EPA-600/2-86-028, NTIS PB86-
172095/AS. March 1986.
U.S. Environmental Protection Agency, Office of Research
and Development, Industrial Effects Research Labora-
tory. "Process Design Manual for Stripping of Organics."
Cincinnati, OH. Publication No. EPA-600/2-84-139. Au-
gust 1984.
Question—What is a primary recovery?
Answer—Vapor recovery or collection devices that are
inherently part of the process, e.g., aprimary condenser on
a solventdistillation unit Primary recovery devices are not
considered control devices under the Subpart AA rules.
Question—By semiannual reporting of exceedances, does this
mean an exceedance is a total of 24 hours in 6 months or
must an exceedance last more than 24 hours tobereported?
If an exceedance mustlast longer than 24 hours, then could
not a facility have a4-hour or more exceedance every day?
Whatistherelation of an exceedance to the annual emissions
limit?
Answer—An exceedance must last more than 24 hours to be
reported. Exceedances of shorterduration mustbe recorded
and may be the basis for enforcement action upon a RCRA
inspection. Exceedances provide an indication that the
control equipmentisnotproperlyoperatedandmaintained
as required under the rules. Exceedances and the annual
emission rate limit are different provisions; the emission
rate limit is an emission cap that is not to be exceeded.
Exceedances indicate that the control device is operating
outside design limits.
Question—Do the Subpart AA requirements apply to
incinerators?
Answer—No. Incineration is not one of the unit operations
specified in the rule.
Question—Wouldsoilventingunits and air strippers atgasoline
cleanup sites be brought under the rules by the toxicity
characteristic leachingprocedure(TCLP)rule for benzene?
Answer—IfthesiterequiresaRCRApermitandtheair stripper
is managing a hazardous waste with 10 ppmw or greater
organics, then the air stripper would be covered. Soil
venting units are not covered by the rule because they are
not one of the unit operations specified in the rules.
Questions and Answers
Question—Can a vapor recovery system be operated at less
than 95 percent efficiency if the emission rate limits are
met?
Answer—Yes. The performance requirements for control
devices must be met only when the facility exceeds the
emission rate limits and is required to reduce total process
vent emissions by 95 percent.
Question—The process vent rules require control for sources
exceeding the emission rate limits at 95 percent control
efficiency. Are there any requirements under the RCRA
rulesforcaptureefficiency.sinceoverallcontrolefficiency
is theproductofcapture andremovaVdestructionefficiency
of the control device? Are there any test methods to
determine capture efficiency?
Answer—The closed vent system requirements in the Subpart
AA rules result in 100 percent capture efficiency. Method
21 leak detection monitoring must be conducted on the
closed vent system.
33
-------
-------
Chapter 4
Equipment Leak Standards
Subpart BB
The organic air emission standards for equipment
leaks at hazardous waste treatment, storage, and disposal
facilities (TSDFs) codified in Subpart BB of 40 CFR 264
and 265 are covered in this chapter. The session is de-
signed to provide a basic understanding of the equipment
leak rules to aid Resource Conservation and Recovery Act
(RCRA) permit writers and enforcement personnel in
determining compliance and to aid facility owners and
operators in achieving compliance.
A review of the background of the equipment leak
rules is presented first, followed by a detailed presentation
of the applicability of the rules. The control requirements
are briefly summarized with references to the standards
for details. Waste stream determinations for the purposes
of applicability are covered in detail and the recordkeeping
and reporting, requirements are summarized with refer-
ences to the standard for details of the recordkeeping
requirements.
Subpart BB—Equipment Leak Rules
Resource Conservation and Recovery Act (RCRA) or-
ganic air emission standards for equipment leaks were pro-
mulgated to protect human health and the environment through
reduction of equipment leak emissions at hazardous waste
treatment, storage, and disposal facilities (TSDF). These rules
were promulgated as Subpart BB of Parts 264 and 265 of the
Code of Federal Regulations (CFR). The purpose of this
chapter is to provide a basic understanding of Subpart BB
equipment leak rules, which were promulgated under author-
ity of Section 3004(n) of RCRA.
The highlights of this chapter are presented in Table 4-1:
First, these standards affect equipment that comes into contact
with hazardous organic waste. Second, hazardous waste treat-
ment, storage, and disposal facilities may have hundreds or
even thousands of potential sources or equipment components
such as pumps, valves, and flanges to which the rules could
apply. Third, the standards include requirements for leak
detection and repair for certain equipment; for other potential
emission sources specified equipment is required to reduce
leak emissions. The last point, which is related to recordkeep-
ing, is that compliance with these rules is demonstrated through
the maintenance of records. Therefore, the recordkeeping
aspects of these rules are very important
The chapter is organized into seven sections as shown in
Table 4-2.
Background
These rules were promulgated June 21,1990. The effec-
tive date was December 21, 1990 (i.e., 6 months following
promulgation). Facility owners and operators should have
completed the first leak detection and repair work by the
effective date, if they have equipment that is subject to these
rules.
These standards were adopted in large part from Clean
Air Act (CAA) standards that were promulgated for equip-
ment leaks in other industries, such as the synthetic organic
chemical manufacturing industry, the petroleum refining in-
dustry, and the coke by-product industry. For example, Clean
Table 4-1.
Highlights
Standards generally affect equipment contacting
organic wastes
Facilities may have hundreds of these potential
sources
Standards include leak detection and repair (LDAR)
and specified equipment
Compliance is demonstrated through the mainte-
nance of records
Table 4-2. Topics
Background
. Applicability
Waste stream determination
Control requirements
Recordkeeping requirements
Reporting requirements
Summary
35
-------
Air Act standards were promulgated as 40 CFR 60, Subpart
W, for NSPS and 40 CFR 61, Subpart V, for NESHAP. In
general, the language of these standards was revised to make
them apply to waste management facilities and to format them
according to RCRA specifications. For example, the words
"process operations" were changed to "waste management
units," and the words "process fluids" were changed to "waste."
In addition to these word changes, requirements were added
for inspection and monitoring that would make the rules self-
implementing under the RCRA program. The Parts 264 and
265 rules for equipment leaks are identical except that report-
ing is not required for those facilities covered by the Part 265
rules (i.e., interim status facilities).
Applicability
An applicability decision tree for the rule is shown in the
workshop manual (Figure 4-1). In the first block at the top of
the diagram is the question, "Is this a RCRA facility?" That is,
is it a new or existing hazardous waste treatment, storage, and
disposal facility that requires a subtitle C permit? If it is,
proceed to the next question, which is, "Are certain types of
'equipment* present at the facility?" The equipment covered
Hazardous
Waste &10%
Organic
Subpart BB
Does Not
Apply
by this rule is shown in Table 4-3. If "equipment" is present in
the facility, "Is the waste material at the facility hazardous
waste that contains at least 10% org.mics by weight?" If the
answer is yes, proceed to the next question regarding the type
of service in which the equipment is used. "Is the equipment
operated under vacuum?" If it is operated under vacuum, then
it is exempt; the Subpart BB rules do not apply. If it is
operated at atmospheric conditions or positive pressure, go to
the final question, "Is the unit an exempt unit?" In the work-
shop presentation on process vents, RCRA exempt units are
identified; that same list of units is exempt from the Subpart
BB rules. If the facility, wastes, and equipment meet all the
criteria shown in the applicability diagram, then Subpart BB
does apply to the equipment in the facility.
A list of the types of equipment affected by the rules—
pumps, valves, compressors, sampling connections, open-
ended lines, pressure-relief devices, and flanges—is presented
in Table 4-3. The following figures are diagrams that help to
show why these equipment pieces are potential sources of
emissions for which these rules apply, The first is a schematic
diagram of a centrifugal pump (Figure 4-2). The impeller that
moves the fluid through the pump is at one end of the pump.
Penetrating that impeller housing is a shaft that provides the
motive power for the impeller. A seal or packing along the
shaft prevents leakage to the outside of the wastes that are in
the pump impeller section. When that seal breaks down or
does not operate properly, the fluids from inside the pump can
move along the pump shaft and become exposed to the
atmosphere at the point where a potential leak area is indi-
cated in the figure.
Compressors (Figure 4-3) are similar to pumps. The
difference is that the fluid on which they operate generally is a
gas. The gaseous fluid is on the insiide. Pressure is exerted
inside the compressor, which tends to force waste materials
along the shaft and through the seal! area. Once the gas is
exposed to the atmosphere, it becomes a leak.
A diagram of a gate valve is shown in Figure 4-4. The
waste fluid passes through the valve when the gate is open.
The fluid can leak along the valve shaft; once it penetrates the
packing gland area and becomes exposed to the atmosphere, a
leak or air emission exists.
A flow control valve shaft moves constantly to change
the flow rate through the valve. This shaft movement up and
down creates constant wear on the seal, and the area where the
shaft becomes exposed to the atmosphere is a potential leak
site. Flow control valves, as a result, have a higher potential
for leakage than manual on/off valves.
Table 4-3. Equipment Covered by Subpart BB
Pumps
Valves :
Compressors
Sampling connections systems
Open-ended valves or lines
Pressure-relief devices
Flanges and other connecters
Figure 4-1. Applicability.
36
-------
Potential
Leak
Volute
Impeller
Typical Pump Section
Figure 4-2. Centrifugal pump construction.
Section through Impeller and
Volute along Mean Flow Surface
A diagram of a pressure relief valve is shown in Figure 4-
5. The pressure relief is provided for a process that is located
upstream of the device; the pressure is produced by the fluid
inside the process or waste management unit In this case, the
pressure is exerted upward and may cause the sealing disc to
move and potentially produce a leak if the disc is not reseated
properly.
For flanges, leaks can occur at the area where two pieces
of pipe interface (Figure 4-6). Leaks tend to develop at the
gasket because of vibration, bad assembly, or damage to the
gaskets at the time they were installed when the pipe was put
in place.
The most common site for equipment covered by Subpart
BB at a TSDF is in the waste destruction, recycling, and
recovery operations. Example operations include: incinera-
tion, distillation, solvent extraction, steam stripping, and stor-
age tanks for reclaimed organics. But these are not the only
places that the types of equipment subject to these rules can be
found. If concentrated organic wastes are in tanks or contain-
ers, the auxiliary/ancillary equipment related to that tank or
container management may also be affected by these rules.
Internal
Gas Pressure
Potential
Leak Gas
Atmosphere
Steam strippers (Figure 4-7) commonly are used on rela-
tively dilute aqueous wastes. So a question might be, "Why is
this a type of device where you would find equipment affected
by these rules?" When the waste materials are stripped, the
organic vapor phase passes overhead into an accumulator
tank. When the organic material comes out of the accumulator
tank and passes through the pumps and valves, the stripping
system at these points may be contacting waste materials with
high enough organic content to be subject to these rules.
Waste Stream Determinations
The waste stream determination is that portion of the
applicability diagram that helps you decide whether the waste
materials that contact the equipment are of sufficient organic
content to make the equipment subject to the rules. The
organic content of the hazardous waste must be at least 10
percent by weight This is not an average organic concentra-
Potential
Leak Areas
Disk or Wedge
Figure 4-3. Labyrinth shaft seal for compressors.
Figure 4-4. Rising stem gate valve.
37
-------
Emissions
(Simmering, Improper
Reseating, Pressure Relief)
4
Spring
Possible
Leak Area
Potential
Leak Area
Leaks Caused by
• Improperly Chosen Gaskets
• Damaged Gaskets
• Poor Assembly
• Vibrations
Figure 4-6. Leak area in flanged joint.
Process Side
Figure 4-5. Spring-loaded relief valve.
Valve
Pump
Waste In «EI
Storage and
Feed Tank
Primary Condenser
Vapor Phase
Bottoms Receiver
Process Vent
Figure 4-7. Steam stripper.
38
-------
tion. If at any time the equipment is expected to contain or
come into contact with a hazardous waste that could have 10
percent or greater organic content, that equipment is subject to
the equipment leak rules if it meets the other applicability
criteria.
The second aspect of waste stream determinations is the
type of "service" in which the equipment is used. Is it a gas or
a liquid at the operating conditions, and, if it is a liquid, is it a
light or heavy liquid?
The waste organic content determinations can be based
on prior knowledge that the waste is lower than the 10 percent
limit or by direct measurement or chemical analysis.
Examples of types of acceptable knowledge are: (1)
documentation that no organics are used in the process, (2)
information from an identical process if the waste materials
that are handled in the process for which you are making the
certification are the same, (3) analyses done previously on the
waste managed in the unit when no changes to the waste
materials have been made since that analysis was done. If
questions exist about whether the level of knowledge is ad-
equate, the Regional Administrator can require a direct mea-
surement to demonstrate that the waste is less than 10 percent
organic.
Some analytical methods that can be used to make an
organic concentration determination are listed in Table 4-4.
First, representative samples must be taken; guidance on how
to do that is available in the EPA document SW846, Test
Methods for Evaluating Solid Waste Physical/Chemical Meth-
ods. An analytical technique that is appropriate for the types
of waste being managed must be chosen. Some alternative
ways of making those determinations are found in the table.
If a gas chromatographic method is selected, the appro-
priate detector for the types of compounds that are expected to
be in the waste must be selected (Table 4-5). Some detectors
are more appropriate than others. For instance, if you are
Table 4-4. Applicability of Organic Content Analytical
Methods
Compounds
Method Most Applicable
Table 4-5. Applicability of Organic Analytical Detectors
ASTM E 260-85
(General GC analysis)
ASTM D 2267-88
(Aromatics by GC)
Method 9060 (SW-846)
(Total organic carbon
[TOG])
Method 8240 (SW-846)
(Volatiles by gas
chromatograph/mass
spectrometer [GC/MS])
ASTM E 168-88
(Infrared [IR] analysis)
ASTM E 169-87
(Ultraviolet [UV] analysis)
Multiple compounds
Benzene, toluene, C8, and
heavier aromatics
Organic carbon greater
than 1 mg/L
Generally used to measure
Appendix VIII compounds
in wastewaters, sludges
and soils
Single- or double-component
systems
Single- or double-component
systems
Method
Flame ionization
Photoionization
Hall electrolytic
Compounds
Most Applicable
All
Aromatics
Halogenated
conductivity
device
Nondispersive
infrared
Mass spectrometer
Any compound with
C-H bond
All
working with halogenated solvents, the Cl, F, I, Br, and
carbon content of the material must be measured because the
halogens also count toward the total organic compound con-
centration determination. Therefore, you must add both the
carbon and halogen portions of the waste compounds.
The next question to be answered in determining the
applicability of the equipment leak standards is, "In what type
of service is the equipment used?" At this point, the waste
exceeds 10 percent organic content by weight. The next
question is, "Is the fluid a gas at operating conditions?" An
example of a gas service situation is an overhead stream from
a distillation unit prior to the condenser. If the waste stream is
not a gas at operating conditions, a determination must be
made as to whether it is a light liquid or a heavy liquid.
The light liquid determination is made in several steps
(Table 4-6). First, if the waste stream is a liquid at the
operating temperature, the next step is to determine whether
compounds are present in the waste that have vapor pressures
greater than 0.3 kilopascals at 20°C. If compounds of that type
are in the waste, the concentration of those compounds with
vapor pressures exceeding 0.3 kilopascals must be deter-
mined. If the total concentration of those compounds with
vapor pressures greater than 0.3 kilopascals is 20 percent or
more, then the waste stream is a light liquid. If it does not meet
these criteria, then the liquid is a heavy liquid. Any liquid that
is more volatile than kerosene would probably be a light
liquid. An example of a heavy liquid is No. 6 fuel oil.
Control Requirements
In this segment, control requirements and the standards
used to achieve control of the equipment leak emissions are
described and discussed.
Table 4-6. Light/Heavy Liquid Determination
A light liquid:
Is a liquid at operating temperatures
Contains compound(s) with vapor pressure >0.3 kPa
(0.04 psia) at 20°C (68°F)
Total concentration of pure components with vapor
pressure >C.3 kPa at 20°C is greater than 20%
All liquids not light liquids are heavy liquids.
39
-------
The first type or format of standards to be discussed is
based on work practices. Work practices are based on leak
detection and repair (LDAR) programs. Depending on the
source type, an LDAR program requires leak detection moni-
toring and/or inspection by use of an instrument or by visual
means or by sense of smell. Once a leak has been detected,
repair must be initiated and completed within a specific time
frame. A flame ionization analyzer can be used to monitor for
leaks or a soap bubble solution can be used on nonmoving
equipment or equipment that is not at elevated temperatures
that would cause the liquid to evaporate. The formation of
bubbles is an indication that the valve leaks and needs repair.
Usually, leak detection monitoring by Method 21 (Table
4-7) requires the use of a total organic analyzer to locate leaks
from valves, flanges, and pumps. For purposes of this stan-
dard, leaks are defined as measuring a concentration of 10,000
ppm or greater based on a reference compound. The Subpart
BB rule specifies that the reference compounds for this stan-
dard are methane or n-hexane. In leak detection monitoring,
Table 4-7. Leak Detection Monitoring with Method 21
• Portable total organic analyzer is used to locate leaks from
valves, flanges, and pumps
• A leak Is defined as 10,000 ppm, based on a reference
compound
• The Subpart BB reference compound is methane or n-
hexane
• A response factor must be determined for each comound
to be measured
the response factor of the instrument to each of the com-
pounds that may be leaking from that equipment must be
determined. A certification or demonstration must be made
for EPA that the leak detection equipment (analyzer) used is
capable of responding to all the organic compounds that could
be leaking from the equipment. For additional information,
review the chapter on Method 21 in tlliis workbook.
Once a leak has been detected, repair to the equipment
must be started within 5 calender days. Repairs must be
completed within 15 days of .detecting the leak.
The second type or format of standard that applies to
some of the emission sources regulated under Subpart BB is
an emission limit standard. This standard is based on use of
equipment that has been designed not to leak. No waste must
contact the equipment's external activating mechanisms. For
instance, in a pump, the drive shaft must be isolated from the
waste for it to qualify for compliance with the emission limit
standard. Compliance is based on demonstrating that no de-
tectable emissions (i.e., >500 ppm) are present, which is done
with a leak-detection monitoring device using Method 21.
Compliance must be demonstrated at least annually and more
often if the Regional Administrator believes a problem exists.
Two types of pumps that would qualify under the emis-
sion limit rules are a magnetically coupled pump and a canned
motor pump (Figure 4-8). The canned motor pump is designed
so that a containment can is located around the pump impeller
shaft. A magnetic field is induced on the outside of the
containment can. The field causes the impeller shaft to rotate
without any direct contact between the waste and the drive
shaft for the pump. A schematic diagrams of two additional
leakless pumps is shown in Figure 4-!?.
Thrust
Washers
Bearings
Outer
Coupling
Motor
Volute
Outlet 0-Ring
Volute
Containment
Can
/
Inlet
Inner
Coupling
' Impeller
\
Impeller
PBearing
Motor Rotor/Pump Shaft
Pedestal
a. Magnetically Coupled Centrifugal Pump
b. Canned Motor Centrifugal Pump
Figure 4-8. Soallesa pumps can be designated for no detectable emissions.
40
-------
Inner
Outer Coupling
Coupling x oRing
Bearing
Motor
Shaft
Gear
Pedestal
Magnets
c. Magnetically Coupled Gear Pump
Outlet .Ball and Seat
Cam
Piston
|n|et Diaphragms
d. Hydraulically Backed Diaphragm Metering Pump
Figure 4-9. Schematic diagram of two leakless pumps.
The third type of standard that may apply to emissions
sources affected by this rule is an equipment standard. The
equipment standard specifies the type of equipment that must
be used to comply with the rules, for example, dual mechani-
cal seals on pumps, the use of a closed-vent system and
control device, or, in the case of sampling connections, closed-
loop sampling. Visual inspections must be made of equipment
that is subject to the equipment standard provisions, and if
equipment is vented to a control device, no emissions must be
detectable from the vent system to the control device. Any
leaks detected must be repaired within 15 days.
The control requirements under the Subpart BB equip-
ment leak rules for various types of equipment are summaried
in Table 4-8. The left-most column in Table 4-8 lists the type
of source. The second column gives the type of service in
which that source is used (i.e., light liquid, heavy liquid, or
gas). The next three columns list types of standards that could
apply for certain types of equipment. Because alternatives are
available for certain types of equipment, the primary control
method is indicated in the figure by a box. You may also
comply with the standard for pumps in light liquid service by
using either of the alternative types of controls. The asterisk
(*) in the box indicates that leak detection monitoring is
required for those sources; for example, for pumps in heavy
liquid service, leak monitoring is required if evidence of a
leak is found. So a visual inspection must be made and, if
liquids are seen leaking from the pump, monitoring for leaks
must be done.
Information for pressure-relief devices and flanges and
other connectors is also summarized in Table 4-8. To demon-
strate compliance with the standard for pressure-relief devices
in gaseous service, the emission limit is no detectable emis-
sions.
For compressors, sampling connection systems, and open-
ended lines, equipment standards constitute the primary means
of complying. Notice that for sampling connections systems,
the use of certain types of equipment is the only means of
complying.
The following figures demonstrate various equipment
controls. A pump shaft with dual mechanical seals is shown in
Figure 4-10. Two sets of seals are on the pump shaft; a barrier
fluid is circulated from a reservoir between those two pump
seals and is discharged at the opposite end. The rules specify
requirements for managing this liquid. It can be sent to a
control device or vented into a degassing reservoir connected
to a control device. An alarm must be on the system to
indicate when organic fluids have penetrated into this circulat-
ing barrier fluid.
A type of valve that could be used to comply with the no-
detectable emissions limit is shown in Figure 4-11. A dia-
phragm-type material lines the inside of the valve and pre-
vents any possibility of waste materials moving along the
stem and escaping the valve at the point at which the stem is
exposed to the atmosphere.
Figure 4-12 is a schematic of a sealed-bellows valve. The
bellows prevents contact between the waste material and the
valve stem.
For pressure-relief purposes, rupture discs (Figure 4-13)
are placed over the potential leak source. Rupture discs are
designed to rupture at certain pressures. The discs must be
replaced after a pressure-relief event has occurred so that the
valve can be returned to the condition of no detectable emis-
sions.
Closed-loop sampling systems (Figure 4-14) must be
designed so that no possibility exists for the purged waste
material stream to become exposed to the atmosphere and
produce organic emissions. The purged material must be
returned to the process line or waste management unit or
disposed of by incineration or some other method that elimi-
nates the possibility of organic emissions.
For open-ended lines (Figure 4-15), a cap or plug must be
put on the opening to prevent leaks from the open end.
41
-------
Table 4-8.
Source
Pump
Vafvo
Pressure-
rollof
Control Requirements, Subpart BB Equipment Leak Rules, Summary
Emission Equipment Work
Service Limit Specification Practice
Light
liquid
Heavy
liquid
Gas & light
liquid
Heavy
liquid
Gas
No detectable
emissions
No detectable
emissions
No detectable
emissions
(or) Dual seals, (or) Monthly monitoring
closed vent (and)
weekly inspection
'ir
(or) Monthly monitoring
*
Closed vent
device
Range/
connector
Compressor
Sampling
connection
Opon-
ondod
lino
Uqht& 1 " 1
heavy
liquids
Gas & light
& heavy
liquids
Gas No detectable (or)
emissions
Gas & light
& heavy
liautds
Gas & light
& heavy
liquids
1 . 1
Seal system
with barrier fluid
or closed vent
Closed-purge
system or closed
vent
Cap, plug, flange,
or second valve
^__^ Monitoring Is required if evidence of a leak is found,
I | Indicates the primary control method
Possible Leak into
Sealing Fluid
Sealing-Liquid Inlet
Sealing-Liquid Outlet
Face \
Inner Seal Assembly
Seal Face'
Outer Seal Assembly
Figure 4-10. Double mechanical seal with barrier fluid controls emissions.
42
-------
Flow
Figure 4-11. Handwheel-operated pinch valve.
Body Bonnet
Bellows
Flow i
Figure 4-12. A bolted-bonnet bellows seal globe valve.
To Atmosphere
4
Disk
Vent
Process Side
Figure 4-13. Rupture disk.
Process Line
Figure 4-14.
Sample Container
Closed-loop sampling system (to avoid losses
from sampling).
To estimate equipment leak impacts for the background
information document, model units were developed. The model
unit parameters, A, B, and C, that were used to estimate
national impacts for equipment leaks during development of
the standards are listed in Table 4-9. Model Unit A, the largest
model facility, is characteristic of the numbers of equipment
components that would be found in a large recycling facility;
B represents a small recycling facility or waste incinerator;
and C represents a small tank farm.
The national impact estimates listed by model unit and
the nationwide estimates are given in Table 4-10. The national
emissions from equipment leaks from these types of facilities
were estimated to be about 26,000 metric tons or megagrams
per year. The rules were estimated to be able to achieve an
emission reduction of about 73 percent at an annual cost of
nearly $33 million. One of the components of this cost is the
salary of the persons who do the leak-detection work, but
annual cost also includes the cost of materials for repairing the
leaking pumps and valves and for the leak detection work
necessary for compliance with the standards.
Recordkeeping Requirements
Compliance with the Subpart BB rules is demonstrated
through the maintenance of records; thus recordkeeping is a
very important aspect of the rules.
43
-------
(Perhaps under Sy
Valve
Closed
— 1 —
T
X
^
V.
Pipe
Leak
X >
Cap
Open-Ended Line
(Leaks through Valve)
FJflur* 4-15. Open-ended lines.
Cap When Not
in Use
The sections of the regulation that describe the details of
rccofdkeeping requirements are listed in Table 4-11. Note that
the last one, Information for Determining Exemptions, is
critical. If a claim is made that the equipment in a facility is
not subject to the rules, that information must be retained.
Records must be retained for different periods of time under
the rules. Some records must be retained for only 3 years: the
results of monthly leak monitoring, repair, detectable emis-
sion monitoring work that is done, and any closed-vent con-
trol device operating data that have to be available to show
that those devices have complied with the operating require-
ments. Other records must be maintained for the life of the
facility. An example is the design basis for a control device
that demonstrates that the device is able to meet a 95 percent
control efficiency. The design basis must be kept on record for
Table 4-9. Equipment Leak Model Unite
Model
Unit
A
B
C
Pumps
15
5
3
Valves
364
121
72
Sampling
Connections
26
9
5
Open-
ended
Lines
105
35
21
Pressure-
relief
Devices
9
3
2
Tabla 4-10. Equipment Leak Impacts
Model
Unit
A
B
C
Natton-
wlcte
Emissions
(Mg/yr)
41.1
13.7
8.3
26,200
Emission l
Reductions
(Mg/yr)
30.4
10.2
6.2
19,000
. %
74
74
74
72.5
Capital
Costs*
($)
68.300
27,000
18,700
127
million
Annual
Costs*
($)
31,000
11,900
8,100
32.9
million
the life of the facility to indicate how that determination was
made.
Reporting Requirements
The reporting requirements for these rules (i.e., Subpart
BB) are similar to those for Subpart AA.
A record of control device exceedances must be kept;
situations that go uncorrected for greater than 24 hours must
be reported (Table 4-12). For pumps, valves, and compressors
in light liquid service, and valves in gaseous and light liquid
service, repairs that have not been completed within 15 days
as required by the standards must be reported as an exceedance.
If no exceedances have occurred, filing a report is not neces-
sary. Facilities subject to the interim status provisions of Part
265 are not required to report; however, they must maintain
the exceedance records in the facility operating records.
Summary
To summarize, the equipment leak rules apply to equip-
ment at new or existing hazardous waste treatment, storage,
and disposal facilities that require a Subtitle C permit (Table
4-13). Some recycling units at hazardous waste facilities were
previously exempt but are now covered. Equipment coming
into contact with a hazardous waste that contains at least 10
Table 4-11. General Records RequCrctd
Equipment-specific identification information (Section
264.1064[b])
• Closed-vent system and control device information
(Section 264.1064[e])
Information on equipment not subject to monthly LDAR
(Section 264.1064[g])
Marking of leaking equipment (Section 264.1064[c])
Information on leaking equipmei.it (Section 264.1064[d])
Barrier fluid system sensor information (Section
264.1064fJ])
• Information for determining exemptions (Section
264.10641k])
Costs are In 1986 dollars.
44
-------
Table 4-12. Information Required in Semiannual Reports
(264.1065)
Control device exceedances uncorrected for >24 hours—
dates, duration, cause, corrective measures
• Pumps in LL service, valves in G/LL service, compressors
not repaired in 15 days
• No report required if no exceedances
• Facilities subject to interim status provisions, Part 265, are
not required to report
Table 4-13. Equipment Leak Rules
• Equipment at new or existing TSDF requiring RCRA
Subtitle C permit
Equipment containing or contacting wastes with at least
10% organic
Control requirements vary by type of service—gas, light
liquid, heavy liquid
Recordkeeping requirements to demonstrate compliance
Semiannual reporting of exceedances
percent organic by weight is affected by this rule. The control
requirements vary by the type of service in which the equip-
ment is used: gas, light liquid, or heavy liquid. Recordkeeping
is the means by which the operators can demonstrate compli-
ance; semiannual reports of exceedances are required if
exceedances have occurred within the 6-month period preced-
ing that reporting time.
The types of standards that are available for complying
with Subpart BB for each source are summarized in Table 4-
14. As shown in the table, alternative compliance methods are
available for pumps, valves, compressors, and pressure-relief
devices. For sampling connection systems, flanges, and other
connectors, only one means of compliance is appropriate.
Bibliography
"Hazardous Waste Treatment, Storage, and Disposal Facili-
ties; Air Emission Standards for Volatile Organics Con-
trol." Federal Register, Vol 52, pp 3748-3770. February
5,1987.
"Hazardous Waste Treatment, Storage, and Disposal Facili-
ties—Organic Air Emission Standards for Process Vents
and Equipment Leaks." Federal Register, Vol 55, pp
25454-25519. June 21,1990.
U.S. Environmental Protection Agency. "Fugitive Emission
Sources of Organic Compounds—Additional Informa-
tion on Emissions, Emission Reductions, and Cost" Re-
search Triangle Park, NC. EPA-450/3-82-010. April 1982.
U.S. Environmental Protection Agency, Air Pollution Train-
ing Institute. "APTI Course SI:417 Controlling VOC
Emissions from Leaking Process Equipment" EPA 450/
2-82-015. Research Triangle Park, NC. August 1982.
U.S. Environmental Protection Agency, Office of Air Qual-
ity Planning and Standards. "Hazardous Waste Treat-
ment, Storage, and Disposal Facilities (TSDF)—Back-
ground Information for Promulgated Organic Emission
Standards for Process Vents and Equipment Leaks." EPA-
450/3-89-009. July 1990.
U.S. Environmental Protection Agency, Office of Air Qual-
ity Planning and Standards. "Hazardous Waste TSDF—
Technical Guidance Document for RCRA Air Emission
Standards for Process Vents and Equipment Leaks." EPA-
450/3-89-21. July 1990.
U.S. Environmental Protection Agency, Office of Air Qual-
ity Planning and Standards. "RCRA TSDF Air Emis-
sions—Background Technical Memoranda for Proposed
Standards." EPA-450/3-86-009. October 1986.
U.S. Environmental Protection Agency, Office of Solid Waste,
S W846 "Test Methods for Evaluating Solid Waste Physi-
cal/Chemical Methods." EPA-530/SW-84-631. Septem-
ber 1986.
Table 4-14. Types of Equipment Leak Standards
Sources
Pumps
Valves
Equipment
(or)
Work
Practice
•
(or)
(or)
Emission
Limit
•
•
Compressors
Sampling
connection
systems
Open-ended
valves or lines
Pressure-relief
devices
Flanges and
other connectors
(or)
Questions and Answers
Question—Is the process vent applicability criterion a waste
concentration of 10 ppm versus the 10 percent organics
concentration for equipment leaks? Why the difference?
Answer—The criteria are correct as stated in the question and
the reason is related to the emission potential of the wastes
in the two situations. Fluids in which the organic
concentration was less than 10 percent were not found to
have as significant an emission potential in leaks from the
types of equipment covered by the Subpart BB rules as
discharges from vents on processes where wastes with
lower organic concentrations were managed. The rules are
described as waste-based, meaning applicability is
conditional upon the organic contentof the wastes and their
emission potential from the sources regulated.
45
-------
Question—What is the difference between leak definitions of
10,000 ppm and 500 ppm in the equipment leak rules?
What must happen between 10,000 and 500 ppm?
Answer—For certain types of equipment in certain types of
service (gas/light liquid/heavy liquid), leak detection
monitoring with an instrument that meets the criteria of
EPA Reference Method 21 is required. When a
concentration of 10,000 ppm or greaterisfoundatasource,
a leak is determined to be present The presence of a leak
requires thefacility operator to attempt to complete arepair
of the leak within a certain period of time after identifying
theleak. Detection of the leak is notaviolation of therules,
but failure to repair or attempt to repair within a certain
time period would be a violation.
For other equipment, controls are applied to meet the rules
that are designed to achieve a condition of "no detectable
emissions."Thedemonstration of no detectable emissions
piescntisacompliancetestusingaleakdetectioninstrument
that indicates no concentrations greater than 500 ppm
abovebackgroundconcentrations near theequipment The
compliance test mustbe repeated at least annually to show
that the controls continue to have no detectable emissions.
The rules have been violated if concentrations more than
500 ppm above background are measured.
Question—Are flanges on a valve considered part of the valve
or are they separate sources? Should monitoring be done
with the valve in an open or closed position?
Answer—Each flange on the valve is considered a separate
source under the Subpart BB rules. So three total sources
are associated with the valve, a flange on each end of the
fluid flow path and the valve stem area where the stem exits
the body of the valve. Monitoring of the valve sources
should be done during normal operations (either open or
closed).
Question—Is thepressure/vacuum (P/V) vent on a storage tank
considered a "pressure relief device" for purposes of the
Subpart BB rules, and, if so, does the operator need to
monitor the P/V vent after each time organic liquid is
loaded into the tank?
Answer—No, the pressure/vacuum vent on a storage tank is not
considered apressure-relief device and, therefore, does not
require monitoring.
Question—Is equipment that is used for the management of
recycled (product) materials subject to the Subpart BB
equipment leak rules?
Answer—If the material is a recycled "product" as opposed to
waste, then the equipment it comes into contact with is not
subject to the Parts 264 and 265, Subpart BB equipment
leak rules. Depending on the facility in which the "product"
is handled, the equipment could 1>e subject to equipment
leak rules issued under the authority of the Clean Air Act,
however. Some examples of facility types where this could
happen include petroleum refineries, coke by-product
plants, and synthetic organicchemii^lmanufacturingplants.
The point at which a waste becomes a recycled "product"
may not be clear. Such distinctions may have to be made on
a case-by-case basis.
Question—What provisions are stipulated for inaccessible
equipment? Can elevated pipes with flanges be ignored
until replacement or until evidence of a leak is seen?
Answer—Elevatedpipe flanges cannot beignored.TheSubpart
BB rules require that flanges be monitored by Method 21
within 5 days of finding evidence of a potential leak via
visual, audible, or olfactory means, orbyany other detection
method. First attempt at repair is required within 5 days if
a leak is found and repairs must be completed within 15
, days. Difficult-to-monitor valves and unsafe-to-monitor
valves may be monitored less frequently than others
dependingonthecircumstances.Difficult-to-monitorvalves
must be monitored at least once a year, but valves placed
in operation after June21,1990, arenot granted this relief.
Unsafe-to-monitor valves mustbe monitored as frequently
as practicable during safe-to-mon itor times.
Question—Are any changes anticipated in the leak definition
concentration of 10,000 ppm based on the plannedproposal
of a 500-ppm value for process leztks under the Hazardous
Organic NESHAP (HON) (at refineries, synthetic organic
chemical manufacturing plants)?
Answer—The 500-ppm leak definition is one of many new
requirements in the HON regulatory negotiation package.
The package has not yet been proposed orpromulgatedbut
will be an action under the 1990Clean Air ActAmendments.
No plans have been made at this time to revise the Subpart
BB rules.
46
-------
Chapter 5
RCRA Phase II Air Regulations
Abstract
Under the Resource Conservation and Recovery Act
(RCRA) Phase H rulemaking, the U.S. EPA is developing
new standards and amendments that would control more
treatment, storage, and disposal facility (TSDF) waste
management units and add new requirements and imple-
mentation changes to the existing RCRA air emission
standards under Subpart AA (TSDF treatment unit pro-
cess vents) and Subpart BB (TSDF equipment leaks). A
new Subpart CC would be added to 40 CFR 264 and 265
requiring that organic emission controls be applied to
TSDF tanks, surface impoundments, containers, and cer-
tain miscellaneous units based on the volatile organic
concentration of the waste managed hi the unit. In addi-
tion, compliance with the air emission control require-
ments relevant to tanks and containers under Subparts
AA, BB, and CC would be included as a condition to
maintain a permit exemption for 90-day accumulation
tanks and containers. Also, the U.S. EPA would amend 40
CFR 270.4 to require the owner or operator of an existing
permitted TSDF to comply with the RCRA ah- emission
standards for interim status facilities (40 CFR 265 Sub-
parts AA, BB, and CC) until the facility's permit is modi-
fied or renewed. Finally, to be consistent with Subpart CC,
the U.S. EPA would add to Subparts AA and BB require-
ments for managing spent carbon removed from carbon
adsorbers.
RCRA Phase II Air Regulations
Under authority of Resource Conservation and Recovery
Act (RCRA) Section 3004(n), EPA is developing nationwide
standards to control air emissions from hazardous waste treat-
ment, storage, and disposal facilities (TSDF). These standards
are being developed in a series of phases. For the first phase of
this RCRA regulatory program, EPA promulgated in 40 CFR
264 and 265 air emission standards for TSDF process vents
(Subpart AA) and TSDF equipment leaks (Subpart BB). For
the second phase, EPA proposed on July 22, 1991 (56 FR
33490), rules that would (1) create a new Subpart CC to
control air emissions from more TSDF waste management
units; (2) create two new EPA test methods for implementing
the Subpart CC standards; (3) extend the relevant air emission
control requirements specified in Subparts A A, BB, and CC to
90-day accumulation tanks and containers; and (4) add new
requirements and implementation changes to the existing
Subparts AA and BB standards. The purpose of this chapter is
to summarize the regulatory actions EPA proposed for the
RCRA Phase II air rules.
Organic emissions from TSDF contribute to ambient
ozone formation, affect public health (e.g., increase cancer
risk to humans), and contribute to stratospheric ozone deple-
tion. Like the Subparts AA and BB standards, the Phase II
rulemaking is intended to control total organic emissions from
TSDF. This rulemaking would significantly reduce TSDF
organic emissions beyond the levels controlled by the Sub-
parts AA and BB standards (Figure 5-1).
The Subpart CC standards would establish air emission
control requirements for additional categories of waste man-
agement units at TSDF subject to permitting requirements
under RCRA Subtitle C. Applying the same implementation
approach used for the Subparts AA and BB rules, a new
Subpart CC would be added to Part 264, and a new Subpart
CC would also be added to Part 265. Part 264 applies to
permitted TSDF, and Part 265 applies to interim status TSDF.
The specific Subpart CC requirements in Parts 264 and 265
are identical with one exception; no reporting requirements
exist in Subpart CC for interim status TSDF.
The Subpart CC standards would be applicable to three
broad categories of waste management units at TSDF subject
to RCRA Subtitle C permitting requirements: tanks, surface
impoundments, and containers. In addition, the Phase II
rulemaking would require TSDF waste management units that
are not specifically defined under the RCRA regulations
(referred to as "miscellaneous units") to comply with the
appropriate emission control requirements specified in Sub-
part CC as well as Subparts AA and BB.
The Subpart CC standards are based on a control strategy
that reduces air emissions from those TSDF hazardous waste
streams identified to have a significant organic emission
potential as determined by the amount of volatile organics in a
given waste stream. Organic emission controls are then ap-
plied on each unit managing these waste streams from the
point where the waste is generated through treatment to
remove or destroy the organics in the waste stream in accor-
dance with other RCRA rules (e.g., incinerator standards in
Part 264, Subpart O, or the land disposal restriction treatment
standards in Part 268).
The TSDF owner or operator could demonstrate compli-
ance of an affected TSDF waste management unit with the
Subpart CC standards in one of three ways: (1) install and
47
-------
Hazardous Waste TSDF
Industrial Processes
2%
Surface Coating
20%
Petroleum Marketing
14%
Petroleum Refining
5%
Misc. Solvent Uses
23%
Chemical Manufacture
3%
Misc. Sources
20%
Phase 2
98%
Phase 1
2%
Figure 5-1. National VOC emissions—stationary sources.
operate on the unit the organic emission controls specified in
the rule; (2) determine that the waste managed in the unit at all
times has a volatile organic concentration less than 500 parts
per million by weight (ppmw); or (3) certify that the waste
managed in the unit complies with organic-specific land dis-
posal restriction treatment standards in Part 268. The specific
control requirements for those affected units managing waste
with a volatile organic concentration of 500 ppmw or more
depend on the type of unit.
For tanks, the basic control requirement would be to
cover the tank and vent it through a closed-vent system to a
control device that removes or destroys the organics in the
vent stream by 95 percent As an alternative to using the
control device, a floating roof could be used. Also, a control
device would not be required for certain tanks that contain
wastes having organic vapor pressures below specified limits
and manage the wastes in a "quiescent" manner (i.e., a waste
is not aerated, agitated, or mechanically mixed).
The control requirements for surface impoundments would
be to cover the unit and vent it through a closed-vent system to
a control device that removes or destroys the organics in the
vent stream by 95 percent As with tanks, if the waste in the
surface impoundment is managed in a "quiescent" manner, a
control device would not be required and a floating membrane
cover could be used.
Containers would need to be tightly covered except when
waste is being added to or removed from the container.
Pumpable waste would need to be added by submerged fill. If
the container is used for certain treatment processes, such as
waste fixation, then the container would need to be placed in
an enclosure that is vented to a control device during the
periods when the container is open.
Under existing RCRA regulations in Part 264, Subpart X,
miscellaneous units are permitted on a case-by-case basis.
Each permit contains terms and provisions to protect public
health and the environment based on the similarity of the unit
to the other types of waste management unit categories regu-
lated under RCRA. The Phase II rulemaking would amend
Subpart X to require that the permit conditions for a miscella-
neous unit include compliance with appropriate emission
control requirements specified in Subparts AA, BB, and CC.
This means, for example, if a miscellaneous unit is deter-
mined to resemble a surface impoundment, the control re-
quirements for surface impoundments apply to the unit.
As part of the Phase II rulemaking, EPA is proposing two
new test methods for use in implementing and enforcing the
Subpart CC standards. These methods would be used to
determine which waste streams have a significant organic
emission potential, and therefore need to be controlled. Both
methods are based on relatively simple and easy-to-use proto-
cols that do not require measuring specific organic com-
pounds. Also, both methods would be added to two sets of
EPA test method references: Appendix A to the New Source
Performance Standards in 40 CFR 60 and "Test Methods for
Evaluating Solid Waste, Physical/Chemical Methods" (SW-
846).
The first test method could be used by a TSDF owner or
operator to determine if a waste stream has a volatile organic
concentration less than the 500-ppmw action level specified in
the Subpart CC standards. This method, Reference Method
25D in Appendix A or Test Method 5100 in SW-846, involves
collecting representative samples, heating the sample and
purging it with nitrogen, measuring the carbon and chloride
content, and then using a formula to calculate the volatile
organic concentration value for comparison to 500 ppmw.
The second test method could be used by an owner or
operator to determine if the organic vapor pressure of a waste
is below the vapor pressure limit specified in the Subpart CC
standards so that a control device would not be required for a
tank. This method, Reference Method 25E in Appendix A or
Test Method 5110 in SW-846, involves collecting representa-
tive samples, analyzing the headspace vapor for propane, and
then using a formula to calculate the organic vapor pressure.
Three amendments to existing RCRA air rules would be
added by the Phase II rulemaking. One amendment would
48
-------
affect hazardous waste generators accumulating waste in 90-
day tanks and containers. A second amendment would change
the implementation practice for RCRA air rules under Sub-
parts AA, BB, and CC. The third amendment would add new
requirements for managing spent activated carbon removed
from carbon adsorber control devices used to comply with
Subparts AA and BB.
Under current RCRA regulations, tanks and containers
accumulating waste for 90 days or less at the site where the
waste is generated do not need a RCRA permit provided the
waste generator complies with certain conditions specified in
40 CER 262. As part of the Phase II rulemaking, EPA would
amend the RCRA rules to add an additional condition that a
hazardous waste generator must meet in order for 90-day
accumulator tanks and containers to remain exempt from
needing a RCRA permit This condition would require com-
pliance with the emission control requirements relevant to
tanks and containers specified in Subparts CC, AA, and BB.
To maintain a permit exemption for a 90-day accumulation
tank, for example, the waste generator would need to install
the controls as specified in Subpart CC if the waste in the tank
has a volatile organic concentration of 500 ppmw or more.
Also, specific requirements under Subparts AA and BB may
apply depending on the particular circumstances.
Implementation of RCRA air rules would be changed by
the Phase II rulemaking. Current EPA practice is to require
that interim status TSDF comply with a new RCRA rule by
the rule's effective date, but allow a permitted TSDF to
comply with the new rule when the facility's permit is modi-
fied or renewed. The Phase n rulemaking would amend the
RCRA rules to require compliance with Subparts AA, BB,
and CC by the rule's effective date regardless of the TSDF
permit status. This means a TSDF with a permit issued before
the effective date would comply with the Part 265 standards
until the facility's permit is modified or reissued. A TSDF
with a permit issued or renewed after the effective date would
comply with the Part 264 standards.
Requirements for management of spent carbon removed
from carbon adsorber control devices would be added to
Subparts AA and BB by the Phase II rulemaking. For carbon
adsorbers to remain effective control devices, the activated
carbon eventually needs to be replaced with fresh carbon.
Because the spent carbon is saturated with organics, the
benefits of controlling the emissions from the waste manage-
ment unit would be lost if the organics adsorbed on the spent
carbon are released to the atmosphere when the carbon is
regenerated or disposed of. The Subpart CC standards include
specific requirements for managing spent carbon removed
from carbon adsorbers used to comply with the rule. For
consistency, Subparts AA and BB would be amended to
include the same requirements. These requirements specify
that the TSDF owner or operator certify that the spent carbon
removed from the carbon adsorber is either (1) regenerated or
reactivated by a process that uses organic emission controls or
(2) destroyed in a hazardous waste incinerator.
Summarizing the Phase II rulemaking as proposed, air
emission standards would be established for TSDF tanks,
surface impoundments, containers, and miscellaneous units.
Specific organic emission controls would be required on those
units managing wastes with a volatile organic concentration
of 500 ppmw or more. To implement these standards, EPA is
proposing two new test methods. Also, existing RCRA air
rules would be amended. To maintain a RCRA permit exemp-
tion for a 90-day accumulation tank or container, relevant air
emission controls specified in Subparts AA, BB, and CC
would need to be used. Control requirements under Subparts
AA, BB, and CC in Part 265 would need to be implemented at
permitted TSDF until the facility's permit is modified or
renewed. Subparts AA and BB would be amended to include
the same spent activated carbon management requirements
specified in Subpart CC.
Questions and Answers
Question—Would the proposed Subpart CC standards require
testingof every waste managed ataTSDFinatank, surface
impoundment, or container?
Answer—No. Waste determinations would be required only
when an owner or operator chooses to demonstrate that
controls are notneededonaunitbecause the waste managed
in the unit has a volatile organic concentration less than 500
ppmw, or the owner or operator chooses to place a waste
with an organic vapor pressure below the specified limits
inatank not usingacontrol device. Furthermore, theowner
or operator would be allowed to perform the waste
determinations using either direct measurement or
knowledge of the waste. Direct measurement of the waste
volatile organic concentration or organic vapor pressure
would be performed using the EPA test methods included
in theRCRAPhasellrulemaking.Knowledgeof the waste
would need to be supported by documentation that shows
that the waste volatile organic concentration or organic
vapor pressure is below the specified limit under all
conditions.
Question—Is the 500-ppmw action level specified in the
proposedSubpartCCstandardsfordeterminingtheneedto
apply emission controls to a unit an average value?
Answer—No. The 500-ppmw action level is a maximum volatile
organic concentration not to be exceeded at any time. EPA
intends that only those units be exempted from using
emission controls for which the owner or operator is
reasonably certain that the volatile organic concentration
of the waste managed in the unit consistently remains
below 500 ppmw. If the owner or operator cannot determine
confidently that the volatile organic concentration of the
waste placed in a unit will remain below 500 ppmw at all
times, then theowner or operator should install therequired
emission controls.
49
-------
Question—Forthepurposeofdeterminingifthevolatileorganic
concentration of a waste is below the 500-ppmw action
level, who is responsible for performing the waste
determination—the hazardous waste generator or the TSDF
operator?
Answer—The proposed Subpart CC standards would require
that the waste determination be based on the waste
compositionbefore the waste isexposed to theambientair.
Whenawastegenerator is also theTSDFowner or operator
(c.g., the TSDF is located at the waste generation site),
performing a waste determination before the waste is
exposed to the ambient air can be readily accomplished
since the TSDF owner or operator has custody of the waste
from the point of generation. However, for the situations
where the waste generator is not the TSDF owner or
operator (e.g., the waste isgeneratedatonesiteandshipped
to a commercial TSDF), the TSDF owner or operator
would not have custody of the waste until it is delivered to
the TSDF. In this case, the TSDF owner or operator may
not have access to the waste before it is exposed to the
ambientair. Consequently, the hazardous waste generator
must perform the waste determination if waste is to be
placed in TSDF units not equipped with the specified
emission controls.
Question—Would pollution prevention techniques be allowed
under the proposed Subpart CC standards?
Answer—Yes. The proposed Subpart CC standards would
allow a TSDF owner or operator to reduce the volatile
organic concentration for a specific waste to a level less
than 500 ppmw through pollution prevention and otfier
engineering techniques. For example, if a waste is treated
using a means other than by dilution orevaporation into the
atmospheresothatthevolatileorganic concentration of the
waste is less than 500 ppmw, then emission controls would
not be required on the subsequent downstream tanks,
surface impoundments, containers, andmiscellaneous units
that manage this waste. However, the unit used to treat the
waste would still be required to use controls in accordance
with the appropriate requirements of the Subpart CC
standards.
Question—How long a period would TSDF owners and
operators have to comply with the requirements as proposed
for the Subpart CC standards?
Answer—The TSDF owners and operators would be required
to be in compliance with the Subpart CC standards by the
rule's effective date, which would be 6 months after the
promulgation date of the final rule. Facilities required to
install control equipment would be allowed up to an
additional 18 months beyond the effective date to complete
the design and installation of the equipment provided the
owner or operator has prepared an implementation schedule
by the effective date showing when these controls will be
installed.
Question—How would the proposed amendment requiring
compliance with RCRA air rules by the rule's effective
date regardless of a TSDF's permit status (i.e., removal of
"permit-as-a-shield" policy for RCRA air rules) affect the
implementation of the Subpart AAandBB rules atexisting
permitted TSDF?
Answer—Currently, aTSDF that has been issued a final permit
prior to the promulgation date of the Subpart AA and BB
standards is not subject to the Subpart AA and BB standards
under either Part264 or 265 rules until the facility's permit
is modified or reissued. Upon promulgation of the RCRA
Phase II air rules, owners and operators of these permitted
TSDFs would be required to be in compliance with the
Subpart AA and BB rules under Part 265 within 6 months.
Facilities that would be required to install control equipment
would be allowed up to an additional 18 months to complete
the design and installation of the equipment. This is the
sameperiod of time now allowed for owners and operators
of interim status TSDF to comply with the Subpart AA and
BB rules.
50
-------
Chapter 6
RCRA Overview
Abstract
General information and background on the struc-
ture and operations of the solid and hazardous waste
management programs are provided in this chapter. Its
objectives are to
• Introduce/summarize the Resource Conservation and
Recovery Act (RCRA);
• Discuss the RCRA Subtitle C hazardous waste pro-
gram and its regulations; and
• Discuss the relationship of the air standards to other
rules.
RCRA Overview
Federal regulations and standards dealing with the ongo-
ing management of solid and hazardous wastes are founded in
the Resource Conservation and Recovery Act (RCRA) passed
in 1976. The goals of the legislation are to
• Protect human health and the environment,
• Reduce waste and conserve energy and natural resources,
and
• Reduce or eliminate the generation of hazardous waste as
expeditiously as possible.
The RCRA program is continually evolving as new regu-
lations and standards are developed and promulgated. For
example, the Hazardous and Solid Waste Amendments
(HSWA) of 1984 further refined hazardous waste regulations
(e.g., introducing the land disposal restrictions). Regulations
regarding the management of hazardous wastes associated
with abandoned disposal sites are found in the Comprehensive
Environmental Response, Compensation, and Liability Act
(CERCLA)—commonly known as Superfund—and the Su-
perfund Amendments and Reauthorization Act (SARA).
There are four major programs within RCRA: Solid
Waste Management under Subtitle D; Hazardous Waste under
Subtitle C; Underground Storage under Subtitle I; and Medi-
cal Waste— a 2-year demonstration program under Subtitle J.
The improper management of hazardous waste is prob-
ably one of the most serious environmental problems in the
United States. In 1979, EPA estimated that only 10 percent of
all hazardous waste was managed in an environmentally
sound manner.
The remainder was transported, treated, stored, or dis-
posed of in a way that potentially threatens human health and
the environment Since that time, the amount of hazardous
waste produced has risen steadily.
The Subtitle C program developed under RCRA (Sec-
tions 3001-3019 of the act) is designed to ensure that the
mismanagement of hazardous wastes does not continue.
This is done by creating a federal "cradle-to-grave" sys-
tem to manage hazardous waste (including provisions for
cleaning up releases) and to set forth statutory and regulatory
requirements for
• Identifying hazardous waste;
• Generating hazardous waste;
• Transporting hazardous waste;
• Owners and operators of facilities that treat, store, or
dispose of hazardous wastes;
• Issuing operating permits to owners or operators of treat-
ment, storage, and disposal facilities (TSDFs) and pro-
viding for corrective action for hazardous waste releases;
• Enforcing the Subtitle C program; and
• Transferring the responsibilities of the Subtitle C pro-
gram from the federal government to the states.
The Subtitle C regulations are grouped under Tide 40,
Chapter I, of the Code of Federal Regulations (CFR). Chapter
I is divided into numerous parts.
Each part is further divided into subparts. Parts of 40 CFR
are identified by the word "Part" followed by a number in
Arabic numerals, for example, the TSDF air standards fall
under 40 CFR Part 264 (often written as 40 CFR 264, without
"Part" included), Subparts AA, BB, and CC. The parts in
Chapter I of Title 40 that deal with hazardous waste are listed
in Table 6-1.
Waste Definitions
Materials that are solid wastes and the subset of these that
are defined as hazardous wastes are identified in 40 CFR 261.
Specific exclusions to the definitions of solid and hazardous
51
-------
waste also are identified in Part 261. For example, domestic
sewage is a solid waste but is excluded from the definition of
a hazardous waste.
The hazardous waste definition is divided into four cat-
egories:
• Characteristic wastes—described as wastes that exhibit
hazardous properties such as ignitab'ility, corrosivity, re-
activity, or toxicity;
• Listed wastes—such as wastes from specific and nonspe-
cific generation sources, and discarded and off-specifica-
tion commercial chemical products;
• Mixture rule wastes—(1) a mixture of nonhazardous
waste and a characteristic hazardous waste unless the
mixture no longer exhibits any hazardous characteristic,
or (2) a mixture of a nonhazardous waste and one or more
listed hazardous waste; and
• Derived from rule wastes—any solid wastes generated
from the treatment, storage, or disposal of a hazardous
waste, including any sludge, spill residue, ash, emission
control dust, or leachate (but not including precipitation
runoff). Air emissions are not defined as hazardous waste
because they do not meet the definition of a solid waste
(i.e., solid, liquid, or containerized gas).
The criteria for identifying characteristics of hazardous
wastes and for listing hazardous waste are described in Part
261. The first criterion is that the characteristic be capable of
being defined in terms of physical, chemical, or other proper-
lies that cause the waste to meet the definition of hazardous
Table 6-1.
40CFR
Part
RCRA Hazardous Waste Program—Title 40, Code
of Federal Regulations
Title
260 Hazardous waste management system: general
261 Identification and listing of hazardous waste
262 Standards applicable to generation of hazardous waste
263 Standards applicable to transporters of hazardous waste
264 Standards for owners and operators of hazardous
waste treatment, storage, and disposal facilities
265 Interim status standards for owners and operators of
hazardous waste treatment, storage, and disposal
facilities
266 Standards for the management 'of specific hazardous
wastes and specific types of hazardous waste land
disposal facilities
267 Interim status standards for owners and operators of
now hazardous waste land disposal facilities
268 Land disposal restrictions
270 EPA-administered permit programs: the hazardous
waste permit program
271 Requirements for authorization of state hazardous waste
programs
124 Procedures for decisionmaking
waste in RCRA. The second criterion is that the properties
defining the characteristic be measurable by standardized and
available testing protocols.
Characteristic hazardous wastes exhibit one or more of
the following: ignitability, reactivity, corrosivity, and toxicity,
which are portrayed in Figure 6-1 The definition of each
property ties into test results of waste properties and/or con-
stituents. The toxicity test was amended this year to reflect
specific concentrations of some 40 organic and inorganic
waste constituents in a waste extract derived using the Toxic-
ity Characteristic Leaching Procedures (TCLP), which be-
came effective September 29,1990.
Listed hazardous wastes are divided into four groups:
• Nonspecific industry sources such as degreasing opera-
tions and electroplating;
• Hazardous wastes generated from specific sources such
as petroleum refining;
• Wastes representing discarded and/or off-specification
commercial chemical products and manufacturing chemi-
cal intermediates (whether usable or off-specification);
and
• Wastes from spill residues, contaminated soils, and cleanup
materials.
Wastes are also characterized into RCRA waste codes.
"Characteristic wastes" are labeled as D codes which are
shown on Figure 6-1. "Listed wastes" encompass four groups
of alphanumeric code published in 40 CFR 261, Subpart D.
Hazardous wastes generated from nonspecific industry sources
such as degreasing operations and electroplating are listed as
codes beginning with the letter "F," e.g., F001, spent haloge-
nated degreasing solvents.
Hazardous wastes from specific generation sources such
as petroleum refining are assigned codes beginning with the
letter "K," e.g., K04g, oil emulsion solids from petroleum
refining. Waste codes beginning with "P" or "U" represent
waste commercial chemical products and manufacturing chemi-
cal intermediates (whether usable or off-specification), e.g.,
P037, container residue-dieldrin and U196 spill residue-pyri-
dine.
Generators
Title 40 CFR Part 262 defines a hazardous waste genera-
tor as any
• Facility owner or operator or person who first creates a
hazardous waste;
• Person who first makes the waste subject to Subtitle C
regulations, e.g., mixes hazardous wastes of different
Department of Transportation (DOT) shipping descrip-
tions by placing them into a single container.
The regulations require all solid waste generators to
determine whether any of their waste is hazardous. Once
determined hazardous, the generator may fall into one of three
categories depending on the volume of waste generated:
• Large-quantity generator—generates >1,000 kg/mo of
hazardous waste;
52
-------
Characteristic
RCRA Code
Ignitable
D001
Corrosive
D002
Reactive
D003
Toxic*
D004 - D043
*Toxicity Characteristic Leaching Procedure (effective 9/29/90).
Figure 6-1. Hazardous waste characteristics.
• Small-quantity generator—generates >100 kg/mo and
<1,000 kg/mo of hazardous waste; and
• Conditionally exempt small-quantity generator—gener-
ates <100 kg/mo of hazardous waste (or 1 kg of acutely
hazardous waste).
Generators must comply with specific regulations includ-
ing obtaining an EPA identification number specific for haz-
ardous waste generators, prettansport requirements (e.g., con-
tainer storage, labeling, inspection), manifest requirements
for shipping (part of the waste tracking system), biennial
reporting and recordkeeping requirements, and conditions for
which accumulation is required without the need for a RCRA
hazardous waste management facility permit. The length of
time waste may be accumulated without requiring a storage
permit is
• 90 days for large-quantity generators;
180 - 270 days for small-quantity generators depending
on transportation circumstances; and
• No limit for conditionally exempt small-quantity genera-
tors.
The overwhelming majority of hazardous wastes are pro-
duced by large-quantity generators, i.e., those firms that gen-
erate more than 1,000 kg/mo of hazardous wastes. It has been
estimated that there are about 71,000 large-quantity genera-
tors of hazardous waste in the United States (Figure 6-2).
These generators accounted for more than 99 percent of the
275 million Mg/yr of hazardous waste produced and managed
under RCRA in 1985.
Although small-quantity generators (those that generate
>100 kg/mo and < 1,000 kg/mo of hazardous waste) represent
a large proportion of the number of hazardous waste genera-
tors nationally (more than 26,000), they account for only a
very small fraction of the hazardous wastes generated as
shown in Figure 6-3. About 25 percent of the country's
hazardous waste generators are small-quantity generators; but
these generators contribute less than one-half of the 1 percent
of the total hazardous waste generated. The majority of the
small-quantity generators are automotive repair firms, con-
struction firms, dry cleaners, photographic processors, and
laboratories.
Transporters
EPA and the DOT jointly developed regulations govern-
ing the transportation of hazardous waste. The regulations in
Part 263 incorporate, by reference, pertinent parts of DOT's
rules on labeling, marking, packaging, placarding, and other
requirements for reporting hazardous waste discharges or
spills during transportation. In summary, Part 263 requires
that transporters be subject to regulations on obtaining an
EPA identification number, complying with the manifest sys-
tem, and handling hazardous waste discharges. It should be
Large-Quanity
Generators (75%)
(71,000)
Small-Quantity
Generators (25%)
(26,000)
Source: EPA Office of Solid Waste, April 1984 and June 1986.
Figure 6-2. Hazardous waste generator statistics—number of
generators by generator size.
53
-------
Largo-Quantity
Generators (99%)
(273 Million Mg/yr)
Small-Quantity
Generators (1%)
(2 Million Mg/yr)
Source: EPA OSWER, The Hazardous Waste System, June 1987.
Figure 6-3. Hazardous waste generator statistics—waste
quantity by generator size.
noted that any transporter holding hazardous waste for more
than 10 days is required to obtain a RCRA storage permit
Permitting and Interim Status Standards
TSDFs are the last link in the cradle-to-grave hazardous
waste management system. Subtitle C requires all TSDFs that
handle hazardous waste to obtain an operating permit and
comply with the treatment, storage, and disposal regulations
of Part 265 before fully permitted and Part 264 once permit-
ted.
RCRA permits are required for any facility that treats,
stores, or disposes of hazardous waste. Parties are exempt
from permitting if
• They generate the waste and accumulate it for a limited
amount of time (e.g., for less than 90 days if large-
quantity generators);
• The waste is being managed in an emergency situation; or
• An imminent and substantial danger exists that requires
immediate waste management.
Interim status facilities are those that have not yet been
permitted. To qualify, the TSDF must be in existence when
the permit regulations become effective. The TSDF owner/
operator must notify the authorized agency of its existence
and submit a Part A permit application describing (1) the
waste types managed and their annual quantities, and (2) the
waste management process(es) in use at the TSDF.
It should be emphasized that interim status is only tempo-
rary. It is available only until a TSDF is granted a final permit
decision.
Interim status TSDFs are regulated under 40 CFR Part
265. These are self-implementing regulations that contain
both administrative and technical standards. The administra-
tive standards include rules for developing and implementing
• Waste analysis plans;
• Personnel training programs;
• Contingency plans;
• Manifest systems for waste shipped or received from
offsite;
• Closure and post-closure plans (if a land disposal unit);
and
• Financial responsibility for closure, post-closure, and
liability.
Technical standards for interim status facilities address
specific types of hazardous waste management units. These
include containers, tanks, surface impoundments, wastepiles,
landfills, land treatment units, incinerators, thermal treatment
units, and chemical, physical, and biological treatment units.
As with interim status standards, the components of the
RCRA permit for TSDF fall into two areas: General Facility
Standards and Technical Standards for specific waste man-
agement unit types.
The RCRA permit requires compliance with general stan-
dards on facility security, inspection,, personnel training, and
other programs. Other permit requirements common to all
TSDFs address waste analysis, contingency procedures, train-
ing, closure, etc.
Depending upon the type of hazardous waste manage-
ment processes proposed for the facility, the permit will
specify technical requirements for containers, tanks, and other
waste management units. Unit-specific standards exist for
containers, tanks, surface impoundments, wastepiles, land-
fills, land treatment, incinerators, and miscellaneous units.
To obtain a RCRA permit, the following steps must be
taken: First, the TSDF owner/operator submits a detailed
RCRA Part B permit application. EPA then
• Reviews the application for completeness and technical
adequacy;
• Prepares a draft permit;
• Issues a public notice to local newspapers and radio
stations
notifying the public that a draft permit has been
prepared; or
notifying the public that the permit has been
denied.
• Allows 45 days for receipt of public comment on the
decision;
• Holds a public hearing if requested; and
• Issues a final permit decision arid responds to comments
received.
The public or any interested party has the opportunity to
appeal a permit decision before the permit becomes effective.
54
-------
Interim status facilities regulated in Part 265 have or will
be submitting Part B permit applications to obtain RCRA
operating permits. HSWA established a schedule for final
permitting decisions for interim status facilities. The HSWA
schedule for submitting Part B permit applications and for the
Agency to reach a permit decision is shown in Table 6-2.
Table 6-2. HSWA Schedule for Submitting Part B Permit
Applications
Waste
Management
Process
Land disposal
facilities
Facilities with
incinerators
Other — storage/
treatment and
miscellaneous
units (Subpart X)
Application
Due
November 1985
November 1986
November 1988
Agency
Decision
November 1988
November 1989
November 1992
Land Disposal Restrictions
HSWA mandated a phased approach to prohibit the land
disposal of all untreated hazardous wastes by 1990. In Part
268, EPA has promulgated treatment standards for each haz-
ardous waste code which must be complied with to allow land
disposal of the waste treatment residue. Otherwise,
• A TSDF owner/operator must have an approved petition
that demonstrates that there will be no migration of
hazardous constituents from the disposal unit as long as
the waste remains hazardous (a case-by-case decision);
• A TSDF owner/operator must have an approved petition
that demonstrates that a specific waste cannot be treated
to the RCRA-specified level or by the specified method;
• EPA must determine that the national treatment capacity
is inadequate; or
• The TSDF owner/operator's disposal unit is a surface
impoundment that will be dredged-annually.
The restrictions were divided into the following phases:
solvents and dioxins, California list, first scheduled wastes,
second scheduled wastes, and third scheduled wastes. The
third and final scheduled waste restrictions became effective
May 8,1990. Any newly listed waste (i.e., after 1984) must
have a land disposal restriction determination performed within
6 months of the listing.
State Authority
Part 271 provides the procedures that state hazardous
waste management agencies must follow in order to receive
authority to administer a hazardous waste program in place of
the federal RCRA program administered by EPA. To receive
authority, state hazardous waste programs must be substan-
tively equivalent and equally or more stringent than the fed-
eral program.
Standards Under Development
EPA chose to develop this portion of its TSDF rulemaking
first to prevent uncontrolled air emissions from land disposal
restriction (LDR) treatment technologies since these tech-
nologies were likely to have increased use. In addition, EPA
already had control technology information to support these
regulations, and thus earlier development of these rules was
possible. This is principally because effective controls now in
place under the Clean Air Act (CAA) to control emissions
from the same types of emission points in chemical produc-
tion facilities and petroleum refineries can be applied to
reduce the health risk posed by air emissions from uncon-
trolled distillation, fractionation, thin-film evaporation, sol-
vent extraction, and stripping processes and equipment leaks
atTSDFs.
The EPA has limited the applicability of today's final
standards to those types of process vents for which control
techniques are well developed, i.e., those associated with
processes designed to drive the organics from the waste, such
as distillation, fractionation, thin-film evaporation, solvent
extraction, and stripping operations.
The LDRs are already in place, so there is a need to begin
some level of emission control as soon as possible. The
restrictions will reduce emissions from land disposal units in
most cases, since the designated best demonstrated available
technology (BOAT) has the same goal of reducing organics in
waste. However, BOAT units, other than incineration, will
have process vents and equipment leaks that will remain air
emission sources. The technologies used in lieu of land dis-
posal include the distillation/separation processes subject to
the Phase I rules.
Publication of the June 21, 1990, final rules for air
emissions from hazardous waste management unit process
vents associated with distillation, fractionation, thin-film evapo-
ration, solvent extraction, and air and steam stripping pro-
cesses and from leaks in equipment and piping containing or
contacting hazardous waste marked the completion of this
first phase.
Phase II standards address organic emissions from TSDF
tanks, surface impoundments, and containers. These stan-
dards would substantially reduce emissions of ozone precur-
sors as well as toxic constituents. The regulation of total
organics as a class is relatively straightforward because it can
be accomplished by a single standard, whereas the control of
individual toxic constituents will require multiple standards.
Implementation of the Phase II standards would achieve sub-
stantial organic emission reductions while EPA analyzes the
residual emissions as part of the third phase of the program.
A third phase would involve analyses of individual toxic
constituents that compose the TSDF organic emissions. The
EPA has initiated an effort to improve the database used for
the Phase II TSDF impact analyses. If additional controls are
needed to reduce specific toxic constituent emissions, the
number of constituents requiring the development of stan-
dards is expected to be significantly fewer than if a constitu-
ent-by-constituent approach were used as the only means of
regulating TSDF air emissions. The EPA believes that the
control of organics as a class followed by controls for indi-
55
-------
vidual toxic constituents, if necessary, will result in compre-
hensive standards that are protective of human health and the
environment.
Relationship of Air Standards to Other Rules
Tlircc regulatory programs may have an effect on the
Phase I rules or be affected by the Phase I rules. These are
RCRA's hazardous waste toxicity characteristic, LDRs, and
corrective action along with CERCLA.
Hazardous Waste Toxicity Characteristic
One of the procedures by which EPA defines wastes as
hazardous is through hazardous waste characteristics (ignit-
able, corrosive, reactive, and toxic). This procedure invplves
identifying properties or characteristics of wastes, which, if
exhibited by a waste, indicate that th& waste will pose hazards
to human health and the environment if its management is not
controlled.
Final rules became effective on September 29, 1990, to
modify and significantly expand the existing characteristic of
toxicity. Sections 40 CFR 264.24 and 40 CFR Parti 261,
Appendix II, were amended by adding 25 organic constituents
to the Toxicity Characteristic list of constituents and replacing
the Extraction Procedure CEP) with the TCLP. These changes
identify large quantities of currently nonhazardous wastewa-
ter and additional quantities of sludges and solids as hazard-
ous waste. Consequently, additional waste types and quanti-
ties would be subject to the control requirements of the TSDF
air standards.
Land Disposal Restrictions Under Section
3004(m)
The LDRs, developed under Section 3004(m) of the
HSWA, require that hazardous waste be treated to reduce
concentrations of specific chemicals or hazardous properties
to certain levels or be treated using technologies before the
waste may be disposed on land. Affected land disposal units
include surface impoundments, wastepiles, landfills, and land
treatment units. The EPA anticipates that LDR will substan-
tially reduce the potential for air emissions from these land
disposal sources. The first set of restrictions, for certain
dioxins and solvent-containing hazardous wastes, was pro-
mulgated on November 7,1986 (40 CFR 268.30-268.31); the
second set of restrictions, the California list, was promulgated
on July 8,1987 (40 CFR 268.32). Standards were developed
for wastes having RCRA waste codes in three phases, hence
the name "Thirds." The "First Third" was promulgated on
August?, 1988 (40 CFR 268.33); the "Second Third" on June
23,1989 (40 CFR 268.34); and the "Third Third" on May 8,
1990.
The treatment technologies evaluated under the LDRs for
nonwastewater spent solvents include distillation and other
separation processes subject to the requirements of the Phase I
rules. The proposed Phase n TSDF air standards are designed
to protect human health and the environment by reducing air
emissions from technologies expected to be used to treat
wastes prior to land disposal.
The basis for the proposed Phase n standards is to imple-
ment control measures that would keep the organics in the
hazardous waste stream until the waste is treated or disposed
of in such a manner that the organics iire destroyed, removed,
or otherwise prevented from being released to the atmosphere.
Because all hazardous waste must ultimately be disposed of,
air emission standards are needed that control the release of
organic emissions to the atmosphere during the management
of the waste from the point of generation through the various
treatment processes to the point of disposal. Thus, the LDRs
in combination with air emission standards provide an inte-
grated approach to air pollution control at TSDFs.
Corrective Action Under Section 3004(u)
Under the authority of RCRA Section 3004(u), EPA is
developing regulations to address releases of hazardous waste
or hazardous constituents from solid waste management units
(SWMU) that pose a threat to human health and the environ-
ment Because this authority applies to contamination of soil,
water, and air media, organic air emissions from SWMU at
some TSDFs would be addressed by the corrective action
program. The regulations under development would establish
health-based media-specific trigger levels measured at the
TSDF boundary for determining whether further remedial
studies are required. Health-based cleanup standards would
then be set for air emission or contamination levels that
exceed acceptable health-based levels. When such contamina-
tion or exposure is determined either through monitoring or
modeling techniques, corrective action would be required to
reduce such emissions. Corrective actions and standards are
handled on a site-specific basis. There are no uniform stan-
dards. Any corrective action using one of the six treatment/
separation technologies would be required to comply with
Phase I rules, Subpart AA and/Or Subpart BB. Likewise, any
wastes removed from the site as part of a corrective action
containing wastes >10 ppmw organics and managed in one of
the six technologies would also be subject to the Phase I rules.
CERCLA
The Comprehensive Emergency Response, Compensa-
tion, and Liability Act (CERCLA), as amended by the
Superfund Amendments and Reautlliorization Act of 1986
(SARA), 42 U.S.C. 9601 et seq., authorizes EPA to undertake
removal and remedial actions to clean up hazardous substance
releases. Removal actions typically sire short-term or tempo-
rary measures taken to minimize exposure or danger to hu-
mans and the environment from the release of a hazardous
substance. Remedial actions are longer term activities that are
consistent with a permanent remedy for a release. Remedial
actions are required by CERCLA Section 121(d)(2) to comply
with the requirements of federal and more stringent state
public health and environmental laws that are applicable or
relevant and appropriate requirements (ARAR) to the specific
CERCLA site. The National Contingency Plan (NCP) pro-
vides that CERCLA removal actions should comply with the
federal ARAR "to the greatest extent practicable considering
the exigencies of the circumstances" (40 CFR 300.65(f)). The
equipment leak standards may be considered ARAR for cer-
tain onsite remedial and removal actions.
A requirement under a federal or state environmental law
may either be "applicable" or "relevsmt and appropriate," but
not both, to a remedial or removal action conducted at a
CERCLA site. "Applicable requirements," as defined in 40
56
-------
CFR 300.6, are those federal requirements that would be
legally applicable either directly or as incorporated by a
federally authorized state program to a particular activity if
the activity was not undertaken as a remedial or removal
action pursuant to CERCLA. "Relevant and appropriate re-
quirements" are those federal requirements that, while not
applicable, are designed to apply to an environmental problem
similar to one encountered at a particular CERCLA site and,
therefore, it is appropriate to apply these requirements to a
remedial or removal action performed at the CERCLA site.
Some waste management activities used for remedial and
removal actions to clean lip hazardous organic substances
require use of the distillation/separation operations regulated
under 40 CFR 264, Subpart AA. For example, hazardous
organic liquid wastes and ground and surface waters contami-
nated with hazardous wastes may be treated onsite using air
stripping processes. Therefore, the organic emission control
requirements of the Subpart AA rules may be "applicable" for
onsite remedial and removal action activities that use distilla-
tion, fractionation, thin-film evaporation, solvent extraction,
or air or steam stripping operations that treat substances
identified or listed under RCRA as hazardous wastes and that
have a total organic concentration of 10 ppmw or greater. In
addition, offsite storage, treatment, and disposal of all wastes
classified under RCRA as hazardous waste must be performed
at a TSDF permitted under RCRA Subtitle C. Thus, CERCLA
wastes that are defined as hazardous under RCRA that contain
more than 10 ppmw of total organics and that are shipped
offsite for management in distillation, fractionation, thin-film
evaporation, solvent extraction, and air or steam stripping
operations would be subject to the final standards as would
any similar RCRA hazardous waste.
The new Subpart AA control requirements for process
vents may also be "relevant and appropriate" to onsite
CERCLA removal and remedial actions that use distillation,
fractionation, thin-film evaporation, solvent extraction, and
air or steam stripping operations to manage substances that
contain organics not covered by this rule (e.g., organics less
than 10 ppmw or organics from nonhazardous wastes).
The final rules do not include control requirements for
process vents on operations not associated with organics
distillation/separation but typically associated with CERCLA
remedial or removal actions such as soil excavation, in situ
soil vapor extraction, in situ steam stripping of soil, soil
washing, stabilization, bioremediation (in situ or otherwise),
dechlorination, and low-temperature thermal desorption.
The organic emission control requirements of Subpart
BB for TSDF equipment leaks may also be considered as an
ARAR for the equipment components (e.g., pumps and valves)
installed at CERCLA cleanup sites that contain or contact
substances containing 10 percent by weight or more total
organics.
Although the final standards would not be ARAR for all
types of remedial and removal actions that are potential
sources of organic air emissions, other existing RCRA or
CAA regulations may qualify as ARAR for many of these
activities. For example, Subpart O of 40 CFR 264 establishes
standards of performance limiting organic emissions from
thermal destruction processes (i.e., hazardous waste incinera-
tors).
Other Existing RCRA Air Standards
In addition to the promulgation of Phase I air emission
standards, the EPA has promulgated several standards under
RCRA that reduce air emissions from TSDFs. These include
standards for paniculate emissions from land disposal units,
particulates, metals, chloride, and carbon monoxide emissions
from incinerators and boilers and industrial furnaces, general
air protection standards for miscellaneous waste management
units, unspecified emissions from interim status thermal treat-
ment units, and the 1990 emission standards for process vents
and equipment leaks at TSDFs. Nonparticulate air emissions
from waste management units such as tanks, containers, and
impoundments are currently not regulated. Thus, it is EPA's
charge under Section 3004(n) of HSWA to develop such
standards as determined necessary.
Land Disposal Units—Particulates
Several existing provisions in 40 CFR 264 (40 CFR
264.251[f], 264.301[i], and 264.273[fJ) require the implemen-
tation of general design and operating practices at permitted
wastepiles, landfills, and land treatment operations to limit the
release of paniculate air emissions. The EPA has prepared a
technical guidance document to aid in the implementation of
these paniculate rules; the document (Hazardous Waste
TSDF—Fugitive Paniculate Matter Air Emissions Guidance
Document, EPA-450/3-89-019) provides information on the.
sources of and control technology for paniculate air emissions
at TSDFs.
Miscellaneous Units
40 CFR 264, Subpart X, contains provisions that require
prevention of air releases that may have adverse effects on
human health and the environment at miscellaneous hazard-
ous waste management units. Miscellaneous units are those
units that are not containers, tanks, surface impoundments,
wastepiles, land treatment units, landfills, incinerators, boil-
ers, industrial furnaces, underground injection wells, or units
eligible for a research, development, and demonstration per-
mit. Miscellaneous units would include detonation units and
salt domes.
Incinerators
Air standards also have been promulgated for the control
of air emissions from permitted hazardous waste incinerators
(40 CFR 264, Subpart O). These standards require that incin-
erators be operated to achieve a destruction and removal
efficiency (DRE) of at least 99.99 percent for those principal
organic, hazardous constituents listed in the facility permit.
Higher efficiencies are required when the incinerator is burn-
ing certain specified waste types, e.g., polychlorinated biphe-
nyls. These standards also limit air emission of organics,
hydrochloric acid, and particulates from incinerator stacks.
EPA proposed revised standards in April 1990 that also
require risk-based emission limits on metal chloride species
and products of incomplete combustion using carbon monox-
ide as an indicator.
57
-------
Thermal Treatment
Interim status standards for thermal treatment units other
than incinerators (such as wet air oxidation) are found in 40
CFR 265, Subpart P. These standards apply to facilities that
thermally treat hazardous waste in devices other than enclosed
devices using controlled flame combustion. The standards
require monitoring of visible emissions and operating condi-
tions of the combustion devices and prohibit open burning
except for open burning and detonation of waste explosives.
Boilers and Industrial Furnaces
The EPA also has promulgated standards covering the
burning of hazardous waste in boilers and industrial furnaces
(December 31, 1990; published in the Federal Register).
These standards would require such burning to achieve a DRE
of 99.99 percent for each principal organic hazardous con-
stituent identified in the facility permit. The proposed stan-
dards also have provisions for exempting the burning of low-
risk wastes when the risk posed to the most exposed indi-
vidual is less than 1 in 100,000. For noncarcinogenic com-
pounds, exemptions may be allowed if the resulting air con-
centrations do not exceed the reference concentration (RfC) of
individual hazardous compounds. The proposed standards
would also limit emissions of carbon monoxide, metals, and
hydrochloric acid from boilers and furnaces burning hazard-
ous wastes.
Bibliography
1. RCRA Orientation Program. U.S. Environmental Pro-
tection Agency, Office of Solid Waste, Prepared by the
University of Michigan Press. 1990.
2. 45 FR 33084. Hazardous Waste Management System;
Identification and Listing of Hazardous Waste. May
19,1990.
3. 55 FR 11798. Hazardous Waste Management System;
Identification and Listing of Hazardous Waste; Toxic-
ity Characteristics Revisions. March 29,1990.
4. Solid Waste Disposal Act, Title H—Solid Waste Dis-
posal, Subtitle C—Hazardous Waste Management, Sec-
tion 3005(c)—Permits for Treatment, Storage, or Dis-
posal of Hazardous Waste: Permit Issuance.
5. Solid Waste Disposal Act, Title II—Solid Waste Dis-
posal, Subtitle C—Hazardous Waste Management, Sec-
tion 3004(m)—Standards Applicable to Owners and
Operators of Hazardous Waste Treatment, Storage, and
Disposal Facilities: Treatment Standards for Wastes
Subject to Land Disposal Protiibition.
6. Research Triangle Institute, Source Assessment Model-
chemical universe.
7. U.S. Environmental Protection Agency. Summary Re-
port on RCRA Activities for May 1986. Office of Solid
Waste. Washington, DC. June 16, 1986. p. 4.
8. U.S. Environmental Protection Agency. The Hazard-
ous Waste System. Office of Solid Waste and Emer-
gency Response. Washington, DC. June 1987. p. 1-4.
9. Reference 7, p. 4.
10. Abt Associates, Inc. National Small Quantity Hazard-
ous Waste Generators Survey. Prepared for the U.S.
Environmental Protection Agency, Office of Solid
Waste. Washington, DC. February 1985. p. 2.
11. Westat, Inc. National Survey of Hazardous Waste Gen-
erators and Treatment, Storage, and Disposal Facilities
Regulated under RCRA in 1981. Prepared for the U.S.
Environmental Protection Agency, Office of Solid
Waste. April 1984. p. 65.
12. Reference 11, p. 69.
13. Reference 7, p. 4.
58
-------
Chapter?
Implementation of RCRA Air Regulations
The Treatment, Storage, and Disposal Facility (TSDF)
Air Emissions Standards, Subparts AA (Process Vents) and
BB (Equipment Leaks) are self implementing. The rules be-
came effective 6 months after the promulgation date, or
December 21,1990. Some facilities will have up to an addi-
tional 18 months to install control devices. The actual effec-
tive date for specific facilities depends on the type of facility
with regard to its permit status. Phase II, currently undergoing
Office of Management and Budget (OMB) review, will also
have an impact on the implementation of Phase I.
The self-implementing nature of the regulations mini-
mizes the need for interaction between the permitting agency
and the permit applicant or permittee. The need for interaction
is reduced because the regulations are very specific. The
regulations have specific requirements that a facility must
meet in order to be in compliance. First, facilities must make
applicability determinations, and the regulations include spe-
cific procedures for determining whether a facility is affected
by the regulations. If the rules are applicable to a facility, the
regulations specify how to estimate emissions.
Whether control devices are needed to control air emis-
sions is determined by the facility emissions. If the facility
exceeds the facility emission rate limits of 3.0 Ib/h or 3.1 ton/
yr, then control devices are required to control the emissions.
If control devices are required, performance and operations
standards for those control devices would apply. Therefore,
meeting the requirements that have been specified in the
regulations would ensure compliance with the regulation as a
whole. Because of these specific requirements, the need for
engineering or professional judgment in interpreting the regu-
lations and in applying them to a specific facility is reduced.
To further ease the implementation of the Resource, Recov-
ery, and Conservation Act (RCRA) air rules, the requirements
for interim status facilities under Part 265 and for permitted
facilities under Part 264 are essentially the same, with the
exception that no reporting requirements for interim status
facilities are required.
The air rules have been passed pursuant to 3004(n) of the
Hazardous and Solid Waste Amendments of 1984 (HSWA),
are therefore considered HSWA rules, and will follow an
HSWA implementation schedule. This means that the rules
become effective immediately in all states and that the U.S.
EPA would implement and enforce these rules in all states.
The EPA would continue to do so in nonauthorized states, but
at such a time as HSWA-authorized states have revised their
programs to reflect the new air emissions standards and these
changes have been approved by EPA, then the authority for
implementation and for enforcement would be delegated to
that state.
HSWA-authorized states are required to adopt the HSWA
provisions or the TSDF air standards to maintain their autho-
rization status. Authorized states had a statutory deadline to
adopt the Phase I air regulations by July 1,1990, to maintain
their authorization status. If a statutory change is required to
reflect the new Phase I air standards, an additional year is
available and July 1, 1991, became the deadline. In some
cases the schedule can be extended for up to 6 months for
extenuating circumstances. The states may have or adopt the
equivalent standards as a matter of state law and administer
and enforce these as state law prior to approval of the HSWA
modification authorization.
Delays in the permitting process are likely because of the
inclusion of these air standard requirements into the permits,
an additional layer of complexity in the permitting process.
Delays were likely for those permits scheduled for issuance in
early 1991. This can occur for three major reasons: (1) if the
detailed module approach is used, some delays may occur in
developing permit language that specifically and adequately
addresses the Phase I air standards; (2) if information or data
received from the applicant are either incomplete or of poor
quality and insufficient for permitting decision; and (3) proce-
dural delays, if the permit has gone through public notice
without the inclusion of the air standards. For these facilities,
an additional public notice covering only the Phase I air
standards is required. The whole permit does not need to be
opened, only that portion covering the Phase I standards. The
best way to minimize delays in the permitting process is to
first set up a dialogue between the applicant and the permit-
ting agency to determine what information is required for the
permit and what is the quality of that information, and to call
for any Part B information as early as possible in the process.
To further minimize delays, language associated with the
Phase I air standards should be incorporated into the draft
permit as soon as possible.
When to expect facilities to develop and submit informa-
tion depends upon when the rules become effective for spe-
cific facilities. The effective date of the Phase I air standards is
December 21, 1990. The actual effective date for a specific
facility may be as early as December 21,1990, or may be later
depending upon its permitting status. Information can be
59
-------
expected as early as December 21,1990, for facilities imme-
diately affected by the regulation. The effective date of the
regulations for specific facilities depends upon the permit
status classification of that facility.
For the purposes of discussing the classification of the
effective date for a specific facility, facilities have been di-
vided into five categories: (1) interim status facilities, (2)
permitted facilities, (3) facilities or units that become newly
subject to the RCRA rules (either through a newly listed or
newly identified waste), (4) a newly constructed facility or
unit, and (5) a unit that becomes newly subject to the Phase I
air standards (where a change has been made in the waste
stream concentrations so that they now exceed the waste
classification limits).
Interim status facilities became subject to the air rules on
the effective date, December 21,1990. Any part of the permit
applications that has been submitted before December 21,
1990, or those submitted subsequent to this date must be
modified to include the Phase I air standards. Facilities are
required to install emission control devices, if needed, by the
effective date, December 21, 1990. If they are not able to
install those control devices, an extension period of up to 18
months from that effective date is available. The 18-month
extension period is not a blanket extension and any delays
must be justified. All control devices must be installed as
early as possible, and all must be installed by June 21,1992.
Permitted facilities—those that have received their final
permits before the effective date of the regulations (December
21, 1990)—are effectively shielded from the Phase I air
Standards through the permit-as-a-shield policy. This means
that the rules do not apply to these facilities, and they do not
have to comply with the requirements. The standards can be
applied and added to the permit when the permit is reissued,
modified, or reviewed under the land disposal review. The
Phase I rules provide cause for the agency to modify any
permits under the permit modification procedures outlined in
Part 270.41.
If the Agency initiates a permit modification, headquar-
ters policy is that the Phase I air standards can be applied to
the facility as a whole. However, if an owner/operator- or
facility-initiated permit modification is requested, the Phase I
air standards would apply only to those units subject to that
permit modification. The rules should not be applied to that
facility as a whole. However, the rules may be applied to the
facility as a whole if the permit modification procedures
outlined in Part 270.41 are followed.
For those facilities that become newly subject to RCRA—
through a newly listed or newly identified waste—the air rules
would apply 6 months after the listing of that waste, or the
effective date of the test by which the waste was identified.
These facilities would then become interim status facilities
and follow the interim status rules under Part 265. They would
therefore have up to an additional 18 months from the listing
date of that waste to install control devices. If control devices
are not installed by the effective date of that regulation for that
facility, the operating record must contain either an imple-
mentation schedule that describes when installation control
devices will occur or documentation that the emission rate
limit of 3.0 Ib/h or 3.1 ton/yr has niot been exceeded and
control devices are not needed. This must be in the operating
record at the time of the effective date for that facility.
For newly constructed facilities,, the law requires that
permits issued after December 21, 1990, must include the
Phase I air emission standards in the permit. The law also
requires that any facility must receive final permit prior to the
initiation of construction. Any applications submitted prior to
December 21,1990, must be modified! and resubmitted. In all
cases, controls must be in place and operating upon startup.
No extension is allowed for the installation of controls.
For new units at existing facilities, if the unit is at a
permitted facility, a permit modification is required to address
the air emission standards. The air standards would apply to
that unit on the date that the permit modification is approved.
For new units at interim status facilities, a revised Part A
application is required to justify the need for an additional
unit, and the air standards would apply on the date that the
revised Part A is approved. In all cases, controls must be
installed and operating upon startup of new units. For newly
constructed facilities and new units at existing facilities, no
extensions are allowed for the installation of controls. They
must all be installed and operating on the startup of that
facility or unit.
The waste stream of a facility may change, so that the
concentration of the waste now exceeds the waste classifica-
tion limit, 10 ppm by weight for the Subpart AA process vent
standards or 10 percent for the equipment leak Subpart BB
standards. The air rules would apply on the date that the
facility begins to exceed the waste classification limits. In all
cases, all vents associated with wast&s 10 ppm or greater by
weight are considered affected regardless of whether facility
emissions are above or below the emission rate limit. If
control devices are needed, they must be installed and operat-
ing on the effective date, the date that the facility begins to
exceed the limit. No extensions are permitted for the installa-
tion of control devices allowed for these facilities. Therefore,
if facility owners/operators believe that change has occurred
in the waste stream, they should be conservative in making
their determinations. If a facility begins to exceed the waste
classification limit, and controls to comply with the regula-
tions have not been installed, they woald be considered out of
compliance. The waste classification limit for Subpart AA, 10
ppmw is an annual average, not an instantaneous concentra-
tion limit. Therefore, the facility owners/operators must deter-
mine whether or not they foresee a chance of the facility's
exceeding the waste classification, in order to have sufficient
time to install control devices. By contrast, the Subpart BB
equipment leak standards are instantaneous concentration lim-
its. The instant that equipment comes in contact with wastes
exceeding 10 ppm, they are considered to be affected by the
regulation; controls, if needed, must be installed and operating
and a leak detection and repair (LDAR) program must be in
place.
To demonstrate compliance with the regulations, facility
owners/operators must first determine that they are affected
by the regulations, that theirs is a Subtitle C facility (either
having or needing a RCRA permit), that they manage waste in
one of the six technologies designated in the standards for
60
-------
process vents (Subpart AA), and/or that they exceed the waste
classification limits. The determination of applicability must
be made by the effective date for facilities immediately af-
fected by the regulations (December 21, 1990). They must
document these determinations in the operating record by the
effective date. Information that must be in the operating
record at the effective date includes the waste determinations
of organic concentrations of all waste streams; whether or not
they exceed the waste classification limits of 10 ppmw for
Subpart AA or 10 percent for Subpart BB; and, for process
vents, any emissions estimates either from actual measure-
ment or monitoring data or from engineering calculations.
The facility must also make a determination as to whether or
not control devices are needed at their facility, i.e., if the
facility exceeds the emission rate limit of 3 Ib/h or 3.1 ton/yr.
If either emission rate is exceeded, control devices are needed,
and documentation must exist stating that control device
efficiency will be met—by existing operating records, data
associated with existing control devices, or any documenta-
tion or engineering calculations that indicate devices to be
installed will achieve 95 percent control efficiency or reduce
emissions to below the facility emission rate limits. Certain
requirements and data associated with equipment leaks must
be in the operating record by the effective date (as early as
December 21, 1990). In addition to the applicability determi-
nations, any Method 21 monitoring results and any leak
detection repair records associated with the equipment leak
rules must be documented.
On the effective date, facilities can be considered to be in
one of three states:
1. They can be in full compliance, having made their appli-
cability determination of what facility or the units at their
facility are affected by the regulations, made emissions
estimates to determine whether control devices are needed,
and, if needed, have these control devices installed by the
time of the effective date, December 21, 1990.
2. If emission control devices are required and have not
been installed by the effective date, the facility must have
an implementation schedule in their operating record.
This will be covered in greater detail later in this chapter.
3. A facility owner/operator can document that the emission
rate limit is not exceeded, i.e., that the total facility
emissions from the affected process vents do not exceed
the 3 Ib/h or 3.1 ton/yr, and, therefore, control devices are
not required. In all cases these requirements must be met
by a facility at the time of the effective date in order for it
to remain in compliance. No extension period is allowed
for these requirements.
If installation of control equipment has not been com-
pleted by the effective date, an extension is possible if in-
cluded in the implementation schedule is the statement that
these control devices will be installed within 18 months from
the effective date, as early as June 21, 1990. Further exten-
sions are not possible beyond this date.
The Phase I air standards require information for Part B
permit applications above that already required for a normal
RCRA permit. This information would reflect the Phase I air
standards. The information required for Part B applications
follows that described above for facility documentation of
compliance. The facility must include any documentation
'associated with applicability determinations. Affected facili-
ties are, for the equipment leak standards, those managing
wastes greater than 10 percent, and, for the process vents
standards, those using one of the six designated technologies
and also handling wastes greater than 10 ppmw. Once affected
by the process vent rules, determination that the process vent
emission rate limit is or will be met must also be included. If
the facility emissions from affected process vents are below 3
Ib/h and 3.1 ton/yr, control devices are not needed. If control
devices are needed (emissions above 3.0 Ib/h or 3.1 ton/yr),
controls would reduce emissions below the 3-lb/h, 3.1-ton/yr
limit or, if the limit cannot be met, achieve 95 percent control
efficiency.
For the Subpart BB rules, each piece of equipment must
have a designation of service. Equipment designation is im-
portant because the actual requirements or standards of Sub-
part BB depend upon and vary according to the classification
of that piece of equipment, be it in gaseous, light liquid, or
heavy liquid service. Additionally, for equipment leak rules,
records and reports associated with a leak detection and repair
program must be submitted.
Determining emission rates and control device design can
be done in several ways; a verification must be made that
acceptable methods to calculate emissions and control device
designs have been followed. The regulations define appropri-
ate test methods and are described in the rules. Further, if test
methods are not used, proper engineering design or judgment
should be used. Finally, if controls have not been installed at
the time of the effective date, an implementation schedule
must be submitted with the Part B application and must
include an explanation as to why the units were not installed
by the effective date and the dates by which each unit will be
up and operating.
If control devices have not been installed by the time of
the effective date, procedures must be followed so that the
facility remains in compliance. An extension period of up to
18 months is possible. This extension period is available only
to interim status facilities and newly regulated facilities. The
extensions do not apply to either new facilities or facilities
that become newly subject to the standards due to waste
stream changes resulting in exceedance of the waste classifi-.
cation limit This 18-month period is not a blanket or auto-
matic extension. The rules specify that the equipment must be
installed by the time of the effective date, as early as Decem-
ber 21,1990. If the control devices have not been installed, an
explanation of why they were not installed by the effective
date must be included. The rules allow for an extension if
documentation exists stating that the installation of these
control devices could not reasonably have been expected to
have been completed earlier.
Two reasons are acceptable for not having installed con-
trol devices by the effective date. They are
1. vendor constraints, or documentation that vendors could
not deliver and install control devices at any date earlier,
and
61
-------
2. delay of installation until normal scheduled routine shut-
down of a unit.
Delaying installation until normal routine shutdown is accept-
able only if documentation exists stating that doing so would
actually reduce the overall emissions from that unit. This
would apply to those many control devices, units, or technolo-
gies for which the greatest emission potential occurs during
shutdown and startup of the unit An unscheduled shutdown
may increase the emission potential from the unit so much
that waiting until normal shutdown would actually reduce
emissions and would justify a delay. Economic constraints are
not considered to be a legitimate reason for delay of installa-
tion of controls, though this may be negotiated on a case-by-
case basis.
An implementation schedule is required to be in the
operating record by the effective date. This schedule shows
the dates by which the design and construction for each unit
will be completed. The dates and schedule must be specific
for each unit at the facility. The 18-month extension period is
not a blanket extension; delays for each unit must be justified
and documented.
In all cases, the implementation schedule should show
that the installation of all control devices should be completed
within 18 months of the effective date, by June 21,1992, for
those immediately affected. No further extensions are allowed
for the installation of controls beyond this date.
The rules allow for changes in the extension period if
documentation exists stating that a schedule change could not
reasonably be avoided because of vendor constraints (e.g.,
delivery was not able to be completed by such time). This
exception should be supported and documented with vendor
information (e.g., purchase orders). Extensions for this or any
reason are not allowed beyond the 18-month period.
In all cases the implementation schedule must be in the
facility operating record by the effective date, as early as
December 21, 1990, for those immediately affected by the
regulations. No extension is allowed for the presence of the
implementation schedule in the operating record.
Measures exist in Phase II that will have an impact on the
implementation of the Phase I air standards. The implementa-
tion of the Phase II rules will be essentially the same as that
discussed under Phase I. Provisions included in Phase II that
would have an impact on the implementation of Phase I
include the elimination of the permit as a shield and the
inclusion of accumulation tanks and containers into the Sub-
part AA and BB standards. The removal of the permit as a
shield is being allowed primarily because the rules are self
implementing; that is, they are very specific for facilities
making applicability determinations and determinations of the
need for control devices. If control devices are needed, stan-
dards for design and operation are included in the rule. Stan-
dards for interim status and permitted facilities are essentially
the same. The Office of Air Quality Planning and Standards
(OAQPS) has had success in taking this approach with other
regulations and has that experience to draw from. Also, hu-
man health and environmental benefits are associated with the
reduced emissions that would occur as a result of the Phase I
air standards. Given that many TSDFs are estimated to con-
tribute about 10 percent of the total organics from stationary
sources nationwide, if they were allowed to continue to oper-
ate without having to comply with the Phase I rules, these
emissions would continue to occur, and delayed health and
environmental benefits associated with those reduced emis-
sions would occur. Also, Congress clearly intended to have
these regulations implemented as early as possible and uni-
formly, as stated in the preamble language.
Accumulation is the first step in the hazardous waste
management process and occurs prior to any air emission
control. Air emission potential is probably the highest during
accumulation. The possibility exists of losing most, if not all,
of the volatiles before any controls or standards can be applied
to that waste stream, which reduces the regulatory benefits of
the Phase I rules.
The changes that have been proposed under Phase I will
become effective 6 months after the promulgation of Phase II,
which is anticipated to occur by mid-1992.
What does the removal of a permit as a shield mean?
Those facilities that had their original operating permit before
December 21,1990, were effectively shielded from the regu-
lations and did not have to comply. By removing the permit as
a shield, those facilities that were originally exempt from the
Phase I rules would become subject to the interim status rules
under Part 265. Because they are going to be following the
interim status rules, they will have up to an additional 18
months to install control devices. The interim status rules
would apply directly to that facility until a permit is either
modified or reissued. In essence, the facility would be operat-
ing under dual status. The permit rules under Part 264 would
apply to all other units, while the interim status Part 265 rules
would apply directly to those units at that facility that are
affected by the Phase I regulations.
Phase II would also change the rules governing accumu-
lation tanks and containers. The requirements have been
changed so that Subparts I and J regulations would require
compliance with the Subpart AA process vent standards,
Subpart BB equipment leak standards, and the new Subpart
CC tanks and containers requirements under Phase n in order
for them to maintain their permit exempt status. Phase II is not
going to affect either small-quantity generators or satellite
accumulation exemptions.
In summary, the rules are self implementing, with spe-
cific requirements and procedures for facilities to follow to
determine the applicability of the rules to their facilities and, if
they are applicable, how to make estimates of emissions to
determine the need for control devices and whether a facility
exceeds the waste emission rate limit. Specific design and
operating standards for control devices are available, if they
are needed. For the equipment leak rules, specific procedures
and leak detection and repair (LDAR) programs must be
instituted to comply with the Subpart BB standards. The self-
implementing nature of the rules minimizes the need for
interaction between the permitting agency and the permit
applicant. The Phase I rules became effective on December
21, 1990, but the effective date for individual facilities de-
pends upon the classification of the facility with regard to its
permit status. Interim status facilities are immediately af-
62
-------
fected by the regulations. Other facilities, such as new units or
newly regulated facilities, would become subject on later
dates, and permitted facilities are initially exempt from the
regulations.
The Phase I rules are considered to be HSWA rules,
passed pursuant to 3004(n) of HSWA and therefore will
follow an HSWA implementation schedule. The rules are
effective immediately in all states, implemented and enforced
by EPA. When HSWA-authorized states modify their pro-
grams to address the Phase I air standards and these modifica-
tions are approved by EPA, enforcement and implementation
authority will be delegated to those authorized states. EPA
will continue to enforce and implement the rules in
nonauthorized states. Finally, provisions in Phase II will have
an impact on the implementation of the Phase I rules. This
includes the removal of permit as a shield for those facilities
that are originally exempt by having their final operating
permit issued prior to December 21,1990. After Phase II they
will become subject to the interim status facility for those
units. To maintain their permit exempt status, accumulation
tanks and containers will also be required to comply with the
Subpart AA and BB standards along with the new CC stan-
dards proposed under Phase II.
Questions and Answers
Question—Must the applicant submit determinations of process
vents and equipment not subject to control requirements?
Answer—The determination must be in the operating record; it
is not submitted with the permit application.
Question—Are only the regions authorized to implement the
air regulations? If so, does the state permit writer have
omnibus authority with respect to air emissions?
Answer—Only EPA is currently authorized to implement the
air regulations; however, once authorized state adoption of
regulations is approved, they can implement. Omnibus is
left to the states as policy. The support role depends on the
state and its relationship with the region.
Question—What will trigger the reopening of a permit for these
rules?
Answer—Any openingof the permit(administrative, technical)
would open the units subject to the rules associated with the
permit change. On the basis of excessive residual risk,
omnibus can be used to open a permit under 270.41.
Question—In the process vent presentation, the statement was
made that permitted facilities are shielded from Phase I air
standards. Does this shielding of permitted facilities apply
to both the process vent requirements and to the equipment
leak requirements?
Answer—Yes, until the permit is reissued, modified, or Phase
. II is promulgated.
Question—Do states automatically get authorization for Phase
I if the state is previously authorized?
Answer—No. The state must adopt changes/new regulations
and have the modification approved.
Question—Would the proposed Subpart CC standards require
testing of every waste managed at a TSDF in a tank, surface
impoundment, or containers?
Answer—No. Waste determinations would only be required
when an owner or operator chooses to demonstrate that
controls are not needed on a unit because the waste managed
in the unit has a volatile organic concentration less than 500
ppmw, or the owner or operator chooses to place a waste
with an organic vapor pressure below the specified limits
in a tank not using a control device. Furthermore, the owner
or operator would be allowed to perform the waste
determinations using either direct measurement or
knowledge of the waste. Direct measurement of the waste
volatile organic concentration or organic vapor pressure
would be performed using the EPA test methods included
in the RCR A Phase II rulemaking. Knowledge of the waste
would need to be supported by documentation that shows
that the waste volatile organic concentration or organic
vapor pressure is below the specified limit under all
conditions.
Question—Ifamanufacturingfacility has both final andinterim
status units, does the rule apply?
Answer—The rule applies to interim status units; final permit
units are shielded.
Question—If the permit is opened for an unrelated purpose,
does the facility come under the rules?
Answer—Office of Solid Waste-Headquarters says the rules
would apply only to those units affected by the permit
reopening if the owner/operator initiated the permit
modification. If EPA initiated the opening of the permit,
the rules may be applied to all units.
Question—Is the 500 ppmw action level specified in the
proposed S ubpart CC standards for determining the need to
apply emission controls to a unit an average value?
Answer—No. The 500 ppmw action level is a maximum
volatile organic concentration not to be exceeded at any
time. EPA staff intends that only those units be exempted
from using emission controls for which the owner or
operator is reasonably certain that the volatile organic
concentration of the waste managed in the unit consistently
remains below 500 ppmw. If the owner or operator cannot
determineconfidently that the volatileorganic concentration
of the waste placed in a unit will remain below 500 ppmw
at all times, then the owner or operator should install the
required emission controls.
63
-------
Question—Forthepurposeofdeterminingifthevolatileorganic
concentration of a waste is below the 500 ppmw action
level, who is responsible for performing the waste
determination—the hazardous waste generator or theTSDF
operator?
Answer—The proposed Subpart CC standards would require
that the waste determination must be based on the waste
composition before the waste is exposed to the ambient air.
Whenawastegenerator is also the TSDFowner or operator
(e.g., the TSDF is located at the waste generation site),
performing a waste determination before the waste is
exposed to the ambient air can be readily accomplished
since theTSDF owner or operator has custody of the waste
from the point of generation. However, for the situations
where the waste generator is not the TSDF owner or
operator (e.g., the wasteis generated at one site and shipped
to a commercial TSDF), the TSDF owner or operator
would not have custody of the waste until it is delivered to
the TSDF. In this case, the TSDF owner or operator may
not have access to the waste before it is exposed to the
ambient air. Consequently, the hazardous waste generator
must perform the waste determination if waste is to be
placed hi TSDF units not equipped with the specified
emission controls.
Question—Would pollution prevention techniques be allowed
under the proposed Subpart CC standards?
Answer—Yes. The proposed Subpart CC standards would
allow a TSDF owner or operator to reduce the volatile
organic concentration for a specific waste to a level less
than 500 ppmw through pollution prevention and other
engineering techniques. For example, if a waste is treated
using a means other than by dilution or evaporation into the
atmosphere so thatthevolatileorganic concentration of the
waste is less than 500 ppmw, emission controls would not
be required on the subsequent downstream tanks, surface
impoundments, containers, and miscellaneous units that
manage this waste. However, the unit used to treat the
waste would still be required to us:e controls in accordance
with the appropriate requirements of the Subpart CC
standards.
Question—How long a period would TSDF owners and
operators have to comply with therequirements as proposed
for the Subpart CC standards?
Answer—The TSDF owners and operators would be required
to be in compliance with the Subpart CC standards by the
rule's effective date which would be 6 months after the
promulgation date of the final rule. Facilities required to
install control equipment would be allowed up to an
additional 18 months beyond the effective date to complete
the design and installation of the equipment provided the
owner oroperatorhasprepared an Implementation schedule
by the effective date showing when these controls will be
installed.
Question—How would the proposed amendment requiring
compliance with RCRA air rules by the rule's effective
date regardless of a TSDF's permit status (i.e., removal of
"permit-as-a-shield" policy for RCRA air rules) affect the
implementation of the S ubpart AA and BB rules at existing
permitted TSDF?
Answer—Presently, a TSDF that has been issued a final permit
prior to the promulgation date of the Subpart AA and BB
standards is not subject to the Subpart A A and BB standards
under either Part 264 or 265 rules until the facility's permit
is modified or reissued. Upon promulgation of the RCRA
Phase II air rules, owners and operators of these permitted
TSDFs would be required to be in compliance with the
Subpart A A and BB rules under Part 265 within 6 months.
Facilities that would be required to install control equipment
would be al lowed up to an additional 18 months to complete
the design and installation of the equipment. This is the
same period of time now allowed For owners and operators
of interim status TSDF to comply with the Subpart AA and
BB rules.
64
-------
Chapter 8
Case Study:
Measuring and Estimating Emissions
This chapter is provided primarily as information that
may be of interest and not as guidance for implementing the
rules that are the topic of the workshop. None of the rules
covered in the workshop require that the owner/operator of an
affected source measure or estimate emissions. Under the
Phase II rule for process vents (Subpart AA), the owner/
operator of the source has the option of measuring emissions
from process vents.
If the source has not been constructed, emissions must be
estimated either by using emission models or by analogy to an
existing source where emission measurements have been made.
For enclosed vented sources, emission measurements are the
preferred choice because they can be determined with a high
degree of accuracy. On the other hand, open area sources are
very difficult to measure and may be candidates for emission
modeling. Some of the techniques to be discussed for open
area sources may be very inaccurate. In such cases, emission
models may provide estimates that are equally or more accu-
rate than attempts to measure the emissions.
Emission models may also be useful, and much less
expensive than measurements, when only an upper bound
estimate of emissions is needed. For cases where significant
variability exists in the way a unit is operated or the quantity
and composition of the waste, emission models can be used to
account for the variability and the effect on emissions. At-
tempts to measure emissions from highly variable sources
could require numerous measurements and significant costs,
often for results that are highly uncertain. Consequently, cost
and available time are often important considerations in de-
ciding whether to measure or estimate emissions.
Emission Measurements
The discussion of emission measurements is divided into
direct measurements of mass emission rates, indirect mea-
surements that involve a back calculation, and engineering
calculations, which involve the use of mass balances.
Direct Measurements
Two types of direct measurement techniques are vent
sampling and the isolation flux chamber. Vent sampling re-
quires that the volumetric flow rate of vapors in the vent be
measured along with the vapor phase concentration of the
organic of interest. Concentration can be analyzed on site with
a gas chromatograph, or samples can be collected in Tedlar
bags, stainless steel canisters, or glass for transport to a
laboratory for analysis. If the concentration is too low for
analysis, the sample can be concentrated by collection on an
adsorbent, such as Tenax or activated carbon, and then des-
orbed for analysis. The basic items for vent sampling are
shown in Figure 8-1. A sample is taken from the vent through
a sampling probe and a filter to remove paniculate matter,
then routed to a sample container or online analyzer.
If the process varies over time or if it is a batch operation,
representative samples must be obtained over the cycle or
during the variations in processing. For steady-state continu-
ous operations, vent sampling can provide very accurate mea-
surements of emissions. Even with process variations or cy-
clic operation, vent sampling can provide accurate results if
care is taken to obtain measurements of flow and concentra-
tion that are representative of the operation over time.
Vent sampling has been used for various types ,of waste
management units, such as vented landfills, vented treatment
systems, vented buildings, storage tanks, etc. Obviously vent
sampling can be used for any source in which the unit is
vented through an enclosed pipe, and the accuracy of the
results depends primarily on the accuracy of the measurement
of flow and concentration.
The isolation flux chamber shown in Figure 8-2 was
developed to measure the flux rate of organics from open area
sources such as surface impoundments and land treatment
facilities. The device is placed over a portion of the open
source. A clean, dry sweep of inert gas is introduced into the
Plexiglas chamber at a metered rate and is mixed with the
vapor in the chamber, either by an impeller or by the design
(e.g., multiple outlets for the sweep gas). The mixture of
sweep gas and vapors is withdrawn from the chamber and
analyzed for organics, either onsite or at an offsite laboratory
if samples are collected in containers. For large area sources,
multiple samples are taken at multiple locations to character-
ize emissions from the entire source.
During its operation, the pressure inside the chamber
must be kept at zero. If a positive pressure exists from the
sweep gas, emissions may be suppressed; if a negative pres-
65
-------
Vent
v,T
Probe
Calibration
Valve
Particulate
Filter or
Separation
Device
Sampling
Pump
Sample
Container or
On-Line
Analyzer/
Recorder
•
I J
Figure 8-1 Vent sampling.
Temperature
Sensor/Recorder
Impeller
Sampling
Port
Plexiglas
Top
Real-Time
Analyzer
Stainless Steel or
Flexiglas
Figure 8-2 Isolation flux chamber and supporting equipment.
sure exists, emissions may be increased by the removal of
more organics from the surface. Another factor to consider is
the sampling of sufficient locations, especially for sources
where the emission rate may vary because of differences in
concentration in the waste as a function of location.
The flux chamber has been evaluated on several different
types of sources, such as active landfills, land treatment,
impoundments, and vents. Its utility for vents is limited to the
case where a very low (almost immeasurably low) flow rate
from the vent exists. In this case, the flux chamber may be a
reasonable approach to measure the emissions that are occur-
ring primarily by diffusion. If the source is heterogeneous
with variation in composition with respect to location, many
samples may be required. Some individuals have commented
that the flux chamber has some shortcomings for measuring
emissions from area sources. For example, when the flux
chamber is placed over a source outdoors, the chamber alters
the emission mechanisms that existed tefore the chamber was
installed. For impoundments, the chamber disrupts the wind
that was blowing across the exposed surface and creating the
emissions.
66
-------
Indirect Measurements
Indirect measurements involve measuring concentrations
of specific organics in the ambient air, and then back-calculat-
ing what the emission rate from the source would be to give
the measured air concentration. One such technique is called
the concentration profile technology. The sampling device
shown in Figure 8-3 consists of six sampling probes that are
mounted vertically and placed at logarithmically spaced inter-
vals. A single mast 4 m in height is placed downwind of the
source in the plume centerline. The concentration, wind speed,
and temperature are measured at each of the probe heights to
generate profiles for each. These profiles are used to calculate
the vertical flux rate from the source.
The sampling equipment can be placed on a trailer or on
a boat for measurements on impoundments. The concentra-
tion profile technique has been used to make measurements
on both surface impoundments and land treatment facilities.
The technique does not work (it is not applicable) when
quiescent or unstable wind conditions exist, such as shifting of
direction. The site must be relatively homogeneous; the tech-
nique will not work well if emissions or waste composition
vary with respect to location.
The transect technology illustrated in Figure 8-4 is also
known as plume mapping. This device uses both a vertical and
horizontal array of sampling probes that are placed downwind
of the source in the plume centerline. The probes are used to
measure the ambient air concentration in a cross section of the
plume. Four probes are mounted on 1.5-m masts and three on
the 3.5-m center mast. Background measurements are made
upwind of the source to correct for the contribution from other
sources. The device also has instruments to measure wind
speed, wind direction, and temperature. The measured con-
centrations are spatially integrated and a Gaussian dispersion
model is used to back-calculate the emission rate from the
source that would be needed to give the measured concentra-
tion.
The transect technique has been used on several types of
area sources, such as active landfills, surface impoundments,
land treatment facilities, and drum storage areas. As with the
concentration profile technology, this technique does not work
when calm wind conditions exist or when the wind conditions
are unstable. It is less susceptible to changing meteorological
conditions than the concentration profile technique, and it is
more suitable to heterogeneous sites provided sufficient sam-
pling stations are used across the plume.
Mass Balance
The mass balance approach shown schematically in Fig-
ure 8-5 focuses on measuring what enters and leaves a unit,
and then calculating what is emitted by difference. For ex-
ample, the flow and concentration can be measured for the
waste that enters an open tank and for the treated waste as it
leaves. Potential air emissions (in the simplest application of
this approach) are calculated from the difference between
what enters and what leaves. If no competing removal mecha-
nisms are in the unit, this approach can provide accurate
results. Even if competing mechanisms exist, the approach
can be used to place an upper bound on the emissions.
Wind
Direction
Indicator
I— 161"
Sampling
Probes
Sampling
Mast
^Real-Time A
XData Collection/
XSystem X
\J
Thermocouple
Ground or Liquid Surface
Figure 8-3 Concentration-profile technology.
67
-------
Temperature
Probe
S- Wind
>v
-------
Overview
Models have proven to be useful in estimating emissions
in many applications. For example, models have been used to
evaluate emission estimates or measurements that others have
made and are also helpful in assessing the emission potential
of sources that are to be constructed. In cases of large open
area sources, measurements are often impractical and model-
ing is the most practical option to estimate emissions. Emis-
sion modeling has other uses, such as understanding what
factors affect emissions and to what extent. For example,
sensitivity analyses using the models can provide'insight into
the major operating parameters, how the variability in these
parameters affects emissions, and how to place reasonable
bounds on the estimates. These models have also been used to
perform one of the several steps (the emission estimates) in an
environmental and health impacts analysis.
Although the models are quite versatile, limitations exist
in the use of the models. The typical system that is being
modeled is always more complex than the relatively simple
models that we use to describe it. There are invariably some
questions about the uncertainties associated with the use of
the model for a specific site and their effect on accuracy. For
example, are all of the assumptions that are used in the model
applicable for the specific case for which the model is being
used? If not, are the model results still close enough? Another
limitation in using the models is the availability of the input
parameters needed to run the model.
The models are relatively simple and require only a few
inputs; however, if these basic inputs are not available, the
models will not provide accurate emission estimates.
Perhaps the most, important concept in understanding
emissions from wastes is that of volatility, which is the
concentration in the vapor divided by the concentration in the
waste at equilibrium. For example, if we have a dilute aqueous
waste containing benzene and place it in a half-filled, tightly
capped vial, roughly 20 percent of the benzene will be in the
vapor phase above the waste and 80 percent will remain in the
waste. If the waste contains phenol instead of benzene, less
than 0.002 percent of the phenol appears in the vapor space.
Consequently, benzene in water is highly volatile, whereas
phenol in water is relatively nonvolatile. In contrast, some
volatiles in mixtures of similar compounds exhibit a lower
volatility than when they are present in water. If the sample in
the vial contained benzene in oil at the same concentration as
benzene in water from the previous example, the amount of
benzene in the vapor space is over 100 times less.
We do not have'equilibrium data for the wide variety of
compounds and types of wastes; consequently, theoretical
relationships are used in the emission models. For aqueous
wastes, volatility is assessed by Henry's law constant, which
is estimated from the pure component vapor pressure divided
by its solubility in water. For organic liquids, the volatility
used in the emission models is usually estimated from the
pure component vapor pressure and the mole fraction in the
waste.
To aid in the discussion of emissions and modeling, the
term "emission potential" is often used and is most easily
pictured for open area sources in which most of the volatiles
are emitted. The potential emissions are bounded on the upper
end by the quantity of waste and the concentration of volatiles
in the waste. The emission models give us a feel for the
fraction of a particular volatile compound that is likely to be
emitted, and the product of waste quantity, concentration, and
fraction emitted provides an estimate of emissions. A critical
point to remember in assessing emission potential or in using
the models is that the concentration that is needed is the
concentration entering the source (for example, at the point of
generation before exposure to the atmosphere). Measuring the
concentration in the impoundment or open tank after most of
the volatiles have been emitted is of little value.
Models for Open Liquid Surfaces
The emissions from open liquid surfaces that are charac-
teristic of surface impoundments and open wastewater treat-
ment tanks are modeled as two mass transfer steps that occur
in series (Figure 8-6). The first step involves the transfer of
the organic through the liquid phase to the surface, followed
by the transfer of the organic from the surface to the air. These
steps are referred to as liquid-phase and gas-phase mass
transfer, respectively. For highly volatile compounds, the rate
of transfer to the air is very rapid relative to the rate of mass
transfer through the liquid; for these compounds, the rate of
volatilization is controlled by the liquid phase rate. Other
compounds such as phenol are not very volatile and the rate of
mass transfer is controlled by the gas-phase rate.
As shown in Figure 8-7, volatility has an important effect
on the tendency of a compound to be emitted. The graph
shows that the fraction of organic compounds emitted in-
creases with volatility up to a point In the example, the
fraction emitted eventually levels off as a function of volatil-
ity; at this point, the rate of emissions of the more volatile
compounds is controlled by the liquid-phase rate and is not
affected by the volatility. The residence time also has an
important effect on emissions as illustrated in Figure 8-8. As
the residence time increases to several weeks, even the rela-
tively nonvolatile compounds such as phenol will be emitted.
The rate of mass transfer through the liquid phase is
affected by the specific compound's diffusivity in the liquid
(usually water), by the wind speed, and by the ratio of fetch/
depth. (Fetch is the distance across the exposed surface of the
source in the direction that the wind is blowing.) The gas-
phase mass transfer is affected by the constituent's volatility,
its diffusivity in air, the wind speed, and the diameter of the
source. If the surface is highly turbulent from mechanical
From Surface to Air
Two mechanisms in series
Through liquid to surface
From surface to air
Rate-controlling step
Liquid phase -
Gas phase
Other removal mechanisms
With effluent
Biodegradation
Sludge
Figure 8-6 Open liquid surfaces—modeling approach.
-------
Phenol
Volatility •
Benzene
Figure 8-7 Effect of volatility on emissions from a surface Impoundment.
1 4 10 46 90 150 365550
Residence Time (Days, Logarithmic Scale)
Figure 8-8. Effect of residence time on emissions from an impoundment.
aeration, additional parameters are needed. For example, the
additional factors affecting emissions from turbulent surfaces
include the horsepower supplied to the aerators, impeller
diameter and speed, and the fraction of the total area that is
turbulent The fraction that is turbulent has a direct effect on
emissions because the rate of emissions is much higher for the
turbulent portion.
As illustrated in Figure 8-9, the modeling must also
consider the presence of mechanisms other than volatilization
that may contribute to the disappearance of an organic com-
pound. The models that will be discussed evaluate removal
with the effluent from the unit, biodegradation within the unit,
and adsorption onto and removal witlti the sludge.
A biodegradation model has been incorporated into the
emission models for those units that are designed to promote
70
-------
Emissions
Wind->
Flow In
Biodegradation
Flow Out
Sludge
Out
Figure 8-9. Fate of organics: emissions, effluent, biodegrada-
tion, sludge.
biodegradation. After review and consultation, the models
were revised to incorporate Monod kinetics to describe the
rate of biodegradation. In Monod kinetics, the rate is first
order with respect to (directly proportional to) the constituent
concentration for very dilute concentrations. At very high
concentrations, the rate of biodegradation becomes indepen-
dent of concentration (zero order). The rate is also propor-
tional to the concentration of biomass in the system.
Data are available for the Monod parameters for over 90
compounds from various biodegradation tests in the literature.
For other compounds, techniques have been devised to esti-
mate the Monod parameters for the model. The first choice is
to use parameters that have been measured for the specific
compounds and the system of interest. A second choice would
be to use values for the same compounds in other systems,
such as the literature values in the emission modeling data-
base. A third choice is to use values for compounds that are
structurally similar to the compound of interest. Finally, some
empirical relationships have been developed to provide rough
estimates of the biodegradation parameters based on the
compound's octanol-water partition coefficient.
Several specialized forms of the models have been devel-
oped for specific applications. For example, the most com-
monly used form of the model is based on well-mixed condi-
tions occurring in the tank or impoundment. However, some
wastewater treatment tanks are designed for plug flow instead
of well-mixed flow. Models are available for both types of
flow systems. Some tanks or impoundments have a layer of
oil floating on the surface of the water. For this case, an oil-
film model was developed. This specialized application of the
model assumes that the gas-phase rate controls the overall rate
of mass transfer, and the volatile organics of interest are in the
oil layer. A model was also developed for diffused air systems
based on the assumption that the rising air bubbles reach
equilibrium with the organics in the liquid. Finally, models
are available for disposal impoundments (no flow out) in
which the waste is placed and the liquid is allowed to evapo-
rate. For this model, the time since disposal must be specified
to estimate emissions.
The typical inputs that must be specified to use the
models for open liquid surfaces (shown in Figure 8-10) in-
clude certain features of the waste, the unit itself, and ambient
conditions. For the waste, the individual constituents must be
Waste:
Constituents
Properties
Concentration
Quantities
Oil Content
1
Process:
Area
Depth
Agitation
Aeration
' Flow Type
^
Site:
Wind Speed
Temperature
1
[ Emission Model |
T
Emission Estimate
Figure 8-10. Typical model inputs (liquid surfaces).
known, their physical properties, concentrations, waste quan-
tity, and the oil content if a separate oil layer forms. For the
process unit (such as the aerated lagoon shown in Figure 8-
11), the input parameters include the surface area, depth, type
of flow, biomass concentration, and certain aeration or agita-
tion parameters if the unit is aerated. The typical wind speed
and ambient temperature are also needed as inputs to the
models.
Models for Porous Solids
The models developed for porous solids include putting
the waste on top of a soil layer or incorporating it into the soil.
For the first case, the modeling assumes that a thin layer of
waste is spread on the soil surface and that the gas-phase rate
of mass transfer is rate controlling. After the waste is mixed
with the soil, the modeling assumes that the air in the soil and
the organics in the soil/waste mixture are in equilibrium. In
addition, the emission mechanism that is modeled is the
diffusion of the organic through air voids to the surface, where
the organics are emitted.
One of the most common questions that has arisen about
these models is the difference between air porosity and total
porosity, which is illustrated in Figure 8-12. Air porosity is
the fraction of the soil/waste matrix that is air. Total porosity
is that fraction of the soil/waste matrix that is not solid, or the
sum of the fractions that are made up of air, water, and oil.
The different pathways for organic compounds in land
treatment are illustrated in Figure 8-13. The model for land
treatment incorporates options for either oily or aqueous
wastes (this affects how volatility is estimated) and accounts
for biodegradation within the soil. The major mechanism for
mass transfer is diffusion through the air voids. Absorption by
oil or water and adsorption onto soil particles are neglected as
alternate removal mechanisms.
The biodegradation model used for land treatment and
landfills is a simple first-order model and not the Monod
model developed for wastewater treatment. The primary basis
is information obtained on the biodegradation of benzene and
toluene in petroleum refinery sludges that are land treated.
These data were used with the biodegradation data for ben-
zene and toluene in water to extrapolate to other compounds
for which the aqueous data were available. Consequently, the
predicted biodegradation in soil is more uncertain than esti-
71
-------
•Wind
Surface Area
Waste In
Biomass Concentration
Figure 8-11. Model inputs for an aerated lagoon.
Vapors Move in Air
Solid
mates of biodegradation in water because of the scarcity of
data.
The typical inputs that are needed for the porous solids
model are shown in Figure 8-14 and include characteristics of
the waste, the land disposal source, and ambient conditions.
The features of the waste that are needed include the constitu-
ents, their properties, concentrations, waste quantity, porosity,
and oil content (if present). For the source (such as the land
treatment plot shown in Figure 8-15), the surface area, depth
of application of the waste, porosity, and the time since the
waste was applied or disposed of are the items needed to run
the models. The typical wind speed £ind ambient temperature
must also be specified. For the covered landfill shown in
Figure 8-16, the cap thickness and its porosity must also be
known.
Figure 8-12. Air porosity vs. total porosity.
Wind
Volatilization
Diffusion
• Through Pores
Adsorption Onto Soil Particles
Absorption into Oil and Water
Figure 8-13. Land treatment emission mechanisms.
72
-------
Waste:
Constituents
Properties
Concentration
Quantities
Porosity
Oil Content
Process:
Area
Depth
Application Time
1
i
Site:
Wind Speed
Temperature
1
Emission Model
Emission Estimate
Figure 8-14. Typical model inputs (porous solids).
Application Method
Waste Loading Area
Porosity '
Figure 8-15. Model inputs for land treatment.
Cap Porosity
Waste Porosity
Figure 8-16. Model inputs for a covered landfill.
73
-------
Questions and Answers
Question—Is EPA recommending or endorsing the use of the
indirect sampling techniques to measure emissions?
Answer—Ho. The information is being provided to let people
know that they exist. However, an important part of the
discussion deals with their limitations, including inaccuracy,
cost, and measurements that represent emissions for a
single point in time. In many cases, mass balance or
emission modeling can provide more accurate long-term
estimates of emissions at a fraction of the cost of the
indirect sampling techniques.
Question—Theschematicofthefluxchambershows an impeller
for mixing. Is this a standard item for all flux chambers?
Answer—No. Mixing is important; however, it can be
accomplished without the impeller by having multiple
outlets for the sweep gas to enter the chamber and mix with
the vapors.
Question—Do the biodegradation models account for the
presence of toxic metals or organics in some wastes that
may inhibit biodegradation?
Answer—No. The models are based on laboratory studies that
involved abiodegradation system that was fully acclimated
to the waste. Consequently, the biodegradation model
assumes that the conditions are favorable for biodegradation.
If the waste contains compounds that will inhibit
biodegradation, the emission model can be run with no
biodegradation (set the biomass equal to zero).
Question—Are the emission models conservative?
Answer—The models were intended to provide unbiased
estimates of long-term emissions. Actual emissions for any
given unitmay be higher or lower than themodel predictions.
By incorporating biodegradation, the models are less likely
to overestimateemissions from biologically active systems.
Question—Are the measurements and estimates for Henry's
law constant based on a single pure component dissolved
in distilled water? If so, is this areasonable approach for the
many constituents and waste matrices that make up
hazardous waste?
Answer—The data for Henry's law constant are as described.
The preferred approach would be to have direct
measurements of aconstituent's volatility from a sampleof
the waste. These measurements have not been made on
very many wastes. Some measurements are based on a
single compound in distilled water, and these are used for
specific compounds when available. In the absence of
measurements, the estimating technique of vapor pressure
divided by solubility in water provides a reasonable
approximation of volatility.
74
-------
Chapters
Benzene Waste Operations NESHAP
NOTE: Since the time the workshops were given, EPA has determined that clarifica-
tions to the Benzene Waste Operations NESHAP are required. Revisions to the rule
were proposed March 5, 1992 (57 FR 8017). Thus interpretations given during the
workshop may have changed. For the latest interpretation, contact Bob Lucas,
Emissions Standards Division, OAQPS (919) 541-0884.
Benzene is listed as a hazardous air pollutant by EPA
because it is a known human carcinogen. National emission
standards for hazardous air pollutants (NESHAP) are estab-
lished by EPA in accordance with Section 112 of the Clean
Air Act (CAA). On March 7, 1990, EPA promulgated the
benzene waste operations NESHAP (Table 9-1). This rule
was one of the last NESHAP promulgated under the "old
Section 112" (i.e., Section 112 as in effect prior to the CAA
Amendments enacted November 15, 1990). The 1990 CAA
Amendments change the approach EPA will use to develop
future air standards for hazardous air pollutants.
As applied to the development of the benzene waste
operations NESHAP, the old Section 112 directed EPA to
establish national standards to control benzene emissions with
an "ample margin of safety" from those sources that present
significant risks to human health. To comply with this direc-
tive, EPA adopted a risk-reduction policy that strives to
achieve a level of emission reduction that (1) limits to no
greater than approximately 1 in 10,000 (also expressed as 1 x
10"*) the estimated additional cancer risk to the individual
living in the location that receives the maximum exposure to
benzene emissions from waste operations (referred to as "maxi-
mum individual risk"), and (2) minimizes the number of
people nationwide exposed to estimated additional cancer
risks of greater than 1 in 1 million (also expressed as 1 x 10'6).
A four-step regulatory approach is used as the basis for
the requirements specified in the benzene waste operations
NESHAP. This approach consists of (1) identifying the facili-
ties where benzene emissions from waste operations pose a
health risk to the people living around the facility; (2) identi-
fying those waste streams that cause the benzene emission
problem; (3) treating the identified waste streams to remove
Table 9-1.
Background of Benzene Waste Operations
NESHAP
Benzene waste rule one of last under "old Section 112"
Rules promulgated March-7, 1990 (45FR 8292)
Impacts of standards
Reduce benzene emissions from 6,000 to 450 Mg/yr
Reduce maximum risk from 2 x 10"3 to 5 x 10'5
Reduce annual cancer incidence from 0.6 to 0.05
or destroy the benzene; and (4) using organic emission con-
trols on all units in which the waste stream is managed prior to
and during treatment.
The EPA performed an analysis to identify those indus-
trial categories where benzene emissions from waste opera-
tions potentially could present a significant risk to human
health. This analysis indicated that large quantities of benzene
can be contained in the wastes generated by chemical manu-
facturing plants, petroleum refineries, and coke by-product
recovery plants. Waste operations at these facilities or at
offsite hazardous waste treatment, storage, and disposal facili-
ties (TSDF) receiving wastes from these facilities are poten-
tial sources of significant benzene emissions to the atmo-
sphere. Therefore, the benzene waste operations NESHAP is
applicable to four specific industrial categories—chemical
manufacturing plants, petroleum refineries, coke by-product
plants, and offsite TSDF that receive wastes from any of these
three industries. Note that if a TSDF receives all of its
benzene-containing wastes from industries other than chemi-
cal manufacturing plants, petroleum refineries, or coke by-
product plants, the rule is not applicable to the TSDF.
Some individual facilities in the affected industrial cat-
egories manage wastes that contain little or no benzene. To
avoid requiring these facilities with low benzene emission
potential to be subject to the treatment and control standards
under the benzene waste operations NESHAP, a cutoff level
related to the facility's benzene emission potential is specified
in the rule. This cutoff level identifies which facilities in the
four affected industrial categories have the potential for pre-
senting significant risks to human health as a result of benzene
emissions from waste operations and, consequently, need to
treat and control benzene-containing waste streams. The cut-
off level is based on the total annual quantity of benzene in the
waste managed at a facility (referred to here as the "facility-"
wide TAB"). The EPA determined that those facilities in the
affected industrial categories with a facility-wide TAB of 10
Mg/yr or more need to control certain waste streams contain-
ing benzene in order to achieve the EPA risk policy goals.
The definition of "waste" used for the benzene waste
operations NESHAP is the same definition used for other
CAA standards (specifically the volatile organic liquid (VOL)
storage New Source Performance Standard [NSPS] in 40 CFR
75
-------
60 Subpart Kb). Note that this definition is not the same
definition of waste used for the Resource Conservation and
Recovery Act (RCRA) rules. The waste definition used for the
benzene waste operations NESHAP is very broad and gener-
ally includes all waste materials generated at a facility except
for those waste materials specifically excluded under the
applicability section of the rule. As specified in this section,
the benzene waste operations NESHAP does not apply to (1)
wastes in the form of gases and vapors, and (2) wastes
managed in segregated stormwater sewer systems (i.e., a
sewer system used exclusively for collecting rainfall runoff at
a facility). Once a liquid or solid waste stream exits the
process unit that generates the waste, that waste stream is
regulated by this rule even if the material eventually is re-
cycled or recovered.
The EPA specified that the facility-wide TAB be calcu-
lated by summing the annual quantity of benzene in all
aqueous waste streams managed at a facility (Table 9-2). An
aqueous waste, for purposes of implementing the rule, is a
waste with a water content of 10 percent or more (or that at
any time is mixed with water or other wastes and the resulting
mixture has a water content of 10 percent or greater). The
facility-wide TAB calculation procedure is based on EPA's
assessment that benzene in aqueous wastes (e.g., process
wastewater, tank drawdown, landfill leachate) are the domi-
nant source of benzene emissions from wastes operations.
However, it is important to note that even though the facility-
wide TAB calculation does not include organic wastes (wastes
with a water content less than 10 percent that are never mixed
with water), benzene emissions from organic wastes contrib-
ute to the overall health risks, and the impacts of the rule were
estimated based on the assumption that these wastes would
also be controlled. Therefore, if the facility-wide TAB is 10
Mg/yr or more, then all benzene-containing waste streams at
the facility regardless of a stream's water content are subject
to treatment and control requirements under the rule. The
water content of a waste stream is relevant only to identifying
whether the waste stream is to be included in the calculation
of the facility-wide TAB.
For the purpose of calculating the facility-wide TAB, an
owner or operator can determine the waste stream quantities
and benzene contents by direct measurement or by his or her
knowledge of the process or operation that generates the
waste. The waste stream quantity and benzene content are
required under the rule to be determined at the point of waste
generation. The general definition of point of waste genera-
tion as used for the rule is the location where a waste exits the
Table 9-2. Total Annual Benzene In Waste (TAB)
TAB=£ (Qfi)
i-1
Q = annual waste quantity
C a annual average benzene concentration
n = number of affected waste streams with
>10% water content
production process or waste management unit that generates it
or the point the waste enters the first downstream waste
management unit provided the waste has not been exposed to
the atmosphere or mixed with other wastes. Determining the
waste benzene quantity at this location ensures that all poten-
tially significant sources of benzene emissions from waste
operations at these facilities are regulated by the rule. Note
that in applying the rule, there are exceptions to this general
definition for a few special situations (e.g., coke by-product
recovery plants regulated by 40 CFR 61 Subpart L and
petroleum refinery sour water plants).
The benzene waste operations NESHAP requires that
certain waste streams containing benzene be treated by a
means other than dilution to remove or destroy benzene, and
each waste management unit that manages the waste prior to
and during treatment must use emission controls. In general,
the waste streams that require control are those streams that
have an annual average benzene concentration of 10 parts per
million by weight (ppmw) or more as determined at the point
of waste generation. In other words, all waste streams with an
annual average benzene concentration less than 10 ppmw are
exempt from the treatment and control requirements.
Under the rule, certain process wastewater streams are
exempt from the treatment and control requirements (Table 9-
3). Process wastewater is a specifically defined in the rule as
water that contacts benzene within the manufacturing process
unit. Specific examples of waste streams that are not process
wastewater are listed in the rule. A process wastewater stream
is exempt if it meets one of two flow conditions regardless of
the benzene content of the stream. First, if the flow rate of a
process wastewater stream is less than 0.02 L/min, it is
exempt from the treatment and control requirements. Second,
if the total mass flow rate of a process wastewater stream is
less than 10 Mg/yr, it is exempt from the treatment and control
requirements. As an alternative to these flow-rate exclusions,
the owner or operator can choose to meet an alternative
standard for all process wastewater streams at an affected
facility. This alternative standard excludes process wastewa-
ter streams with an annual average benzene concentration of
10 ppmw or more from the treatment and control require-
ments provided sufficient process wastewater streams are
treated (in accordance with the requirements of the rule) to
reduce the total amount of benzene in all process wastewaters
at a facility to 1 Mg/yr.
The benzene waste operations NESHAP requires that
affected waste streams with an annual average benzene con-
centration of 10 ppmw or more be treated to remove or
destroy benzene. These treatment requirements are specified
in terms of performance standards. The rule requires that each
Table 9-3. Process Wastewater Exclusions
Waste streams less than 0.02 L/min or 10 Mg/yr
Waste streams >10 ppmw benzene if process wastewater
TAB less than 1 Mg/yr for combination of:
TAB in untreated streams at point of generation
TAB in treated streams at exit to treatment unit
76
-------
affected individual waste stream be treated to (1) remove
benzene from the waste stream to a level less than 10 ppmw
on a flow-weighted annual average basis; (2) remove or
destroy the quantity of benzene in the waste by 99 percent on
a mass basis; or (3) comply with the treatment standards of
other relevant EPA standards (i.e., RCRA waste combustion
rules, RCRA land disposal restrictions, benzene-specific ef-
fluent guidelines and standards). Dilution of the waste stream
to comply with the treatment standards is prohibited. How-
ever, mixing of waste to facilitate treatment is allowed as
described below.
At affected facilities having many wastewater streams
containing benzene such as petroleum refineries, owners and
operators often prefer to combine wastewater streams to fa-
cilitate treatment in a single process. For this situation, there
are special treatment requirements specified in the rule. These
requirements apply to a wastewater treatment system in which
wastewater streams having annual average benzene concen-
trations of 10 ppmw or more are mixed with wastewaters
having annual average benzene concentrations below 10 ppmw
(Table 9-4). A wastewater treatment system is specifically
defined in the rule as a unit that ultimately discharges in
accordance with a National Pollutant Discharge Elimination
System (NPDES) permit. All waste management units mak-
ing up the wastewater treatment system handling these mixed
wastewater streams are required to use controls except for
those units that meet two conditions. The first condition is the
annual average benzene concentration of the waste entering
the unit is less than 10 ppmw. The second condition is the total
annual benzene quantity in the wastewaters first entering all
affected uncontrolled units constituting wastewater treatment
systems facility-wide is less than 1 Mg/yr. Determination of
this total annual benzene quantity does not include wastewa-
ters entering an enhanced biodegration unit. Application of
these special treatment requirements for wastewater treatment
systems can be complex. For additional information about this
provision of the rule, the reader is referred to the case study in
this workbook titled "Application of Benzene Waste Opera-
tions NESHAP to Wastewater Treatment Systems."
The benzene waste operations NESHAP requires that
controls be applied to certain waste management units manag-
ing benzene-containing waste prior to and during treatment
(Table 9-5). In general, the basic control requirements are to
cover the unit and vent the unit through a closed-vent system
Table 9-4. Alternative Standards for WWTS
If wastes with £10 ppmw benzene mixed with wastes <10
ppmw benzene in WWTS, special provisions apply
All units in WWTS must be controlled until both:
The wastes entering an uncontrolled unit are <10
ppmw
The WWTS TAB first entering an uncontrolled unit is
<1 Mg/yr
TAB entering enhanced biodegradation is excluded from
the 1-Mg/yr determination
to a control device that removes or destroys the organics in the
vent stream by 95 percent. The affected waste management
units are tanks, surface impoundments, containers, oil-water
separators, and individual drain systems. The specific control
requirements for each type of waste management unit are
summarized below.
Tanks are required to be covered with a fixed roof, which
is vented through a closed-vent system to a control device that
removes or destroys the organics in the vent stream by 95
percent. As an alternative to using a fixed roof vented to a
control device, an internal or external floating roof can be
used.
Table 9-5. Benzene Waste Operations NESHAP—General
Control Requirements
Apply controls prior to and during treatment
• Cover or enclose waste management unit
Generally, convey emissions through closed-vent system
to control device
Control devices remove or destroy >95% of organics
Surface impoundments are required to be covered and
vented through a closed-vent system to a control device that
removes or destroys the organics in the vent stream by 95
percent.
Containers are required to be tightly covered except when
waste is being added to or removed from the container. Waste
that is transferred (i.e., pumped) into a container must be
added by submerged fill. If the container is used for certain
treatment processes such as waste fixation, the container
needs to be placed in an enclosure that is vented to a control
device during the periods when the container is open.
Oil-water separators are required to be covered and vented
to a control device that removes or destroys the organics in the
vent stream by 95 percent. As an alternative, an owner or
operator may elect to use a floating roof or comply with the
requirements specified in the Petroleum Refinery Wastewater
System NSPS (40 CFR 60 Subpart QQQ).
Individual drain systems are required to have covers
installed and a closed-vent system that routes all organic
vapors from the drain system to a control device. As an
alternative, an owner or operator may elect to comply with the
requirements specified in 40 CFR 60 Subpart QQQ and, in
addition, control box junction emissions by equipping the
junction box with a system to prevent the flow of organic
vapors from the junction box vent pipe during normal opera-
tion (e.g., water seals on the inlet sewer line connections to the
junction box) or connecting the vent pipe to a closed-vent
system and control device (e.g., a carbon canister).
The benzene waste operations NESHAP requires the
owner or operator to submit to EPA an initial report summa-
rizing the initial determination of TAB (Table 9-6). If the
facility-wide TAB is less than 1 Mg/yr there are no further
reporting requirements (Figure 9-1). If the facility-wide TAB
is less than 10 Mg/yr but greater than or equal to 1 Mg/yr, the
owner or operator is required to submit an annual report
77
-------
updating the facility-wide TAB determination. If the facility-
wide TAB is 10 Mg/yr or more, then the owner or operator is
required to submit certification of compliance documenting
the installation and proper operation of all equipment neces-
sary to comply with the treatment and control requirements of
the rule (Table 9-7).
Table 9-6. Initial Determination of TAB
• Existing facilities report June 7,1990
• Updates allowed as new information obtained
• Now sources report at startup
• Report to include:
TAB for wastes with 10% water
Identification of streams to be controlled
Details on basis for benzene waste streams not
controlled
To ensure that the treatment processes and emission
control equipment are properly operated and maintained, the
rule requires the owner or operator to install instrumentation
to monitor the treatment process and control device operation
continuously and to conduct monthly effluent testing for
treatment processes. Emission control equipment covers must
be visually checked at least quarterly to ensure that equipment
is being used properly (e.g., covers are closed and latched
except when workers require access to a tank or container)
and that equipment is being maintained in good condition
(e.g., no holes or gaps have developed in covers). Annual leak
detection monitoring using EPA Reference Method 21 is
required for closed-vent systems to ensure all fittings remain
leak-tight.
As a means of verifying compliance, recordkeeping and
reporting requirements are specified in the rule. The owner or
operator is required to record certain information document-
ing all waste determination results, treatment and control
equipment design, and inspection and monitoring results. This
information must be maintained in onsite facility files for at
least 2 years and must be readily available for review by EPA
enforcement personnel during onsite compliance inspections.
Certain information must be reported to EPA regularly includ-
Initial
Certification:
Annual and
Quarterly
Reporting
ing quarterly and annual reports documenting inspection and
incidences of upset for the treatment processes and control
devices.
Table 9-7. Certification of Compliance
Submitted by March 7, 1992, or by date of new source
startup
• Certifies installation of required equipment
Certifies completion of initial testing and inspections
In summary, the benzene waste operations NESHAP is
applicable to chemical manufacturing plants, petroleum refin-
eries, coke by-product recovery plants, and offsite TSDF that
receive wastes from any of these three industrial categories. If
the facility-wide TAB is 10 Mg/yr or more, the facility owner
or operator is required to treat certain benzene-containing
waste streams having an annual average benzene concentra-
tion of 10 ppmw or more. Tanks, surface impoundments,
containers, oil-water separators, and individual drain systems
used to manage the waste prior to and during waste treatment
must be controlled by covering all openings and venting the
unit through a closed-vent system to a control device that
removes or destroys the organics in the vent stream by 95
percent. For some of the waste management unit categories,
alternative controls may be used.
Questions and Answers
Question—Does the rule require controls for any wastes that
contain benzene when the benzene in the wastes does not
originate from petroleum refineries, chemical plants, or
coke by-product recovery plants?
Answer—-No. Additional clarification has been provided in a
Federal Register notice (55 FR 37230).
Question—Does the rule apply to publicly owned treatment
works (POTW) and municipal solid waste landfills
(MSWLF)?
Answer—For most cases, the rule does not apply to POTW or
to MSWLF. When the coverage of the proposed rule was
clarified in a Federal Register notice (54 FR 51423) on
December 15,1989.POTW and MSWLF werenotincluded.
An additional clarification has been published in th&Federal
Register following promulgation of the rule (55 FR 37230).
There are two special cases in which the rule could apply:
(1) when these facilities are also a commercial hazardous
waste facility with a permit under Subtitle C of RCRA, or
(2) when these facilities accept affected waste streams
from chemical plants, petroleum refineries, or coke by-
product recovery plants. Itis the generator's responsibility
to obtain anagreementfrom the offsite treatmentor disposal
facility to ensure compliance with the benzene waste rule
for treatment of the benzene waste.
Figure 9-1 Benzene waste operations NESHAP reporting
requirements.
78
-------
Question—When must commercial hazardous waste facilities
control wastes that contain benzene?
Answer—Commercial hazardous waste facilities permitted
under Subtitle C of RCRA must apply controls when they
receive benzene waste from chemical plants, petroleum
refineries, or coke by-product recovery plants, and the total
annual benzene in water (TAB) in the wastes received from
these industries is 10 Mg/yr or more. (See the clarification
in 55 FR 37230.) In addition, commercial hazardous waste
facilities must comply with the control requirements for a
specific waste stream if that waste stream has been identified
by the generator as requiring control under the rule.
Question—Are aqueous wastesthatare generated infrequently,
accidentally, or intermittently included in the calculation
of TAB?
Answer—Yes. If aqueous benzene wastes are generated
infrequently, the initial report should include the facility's
estimate of the quantity and concentration for these wastes
based on measurements, historical data, or engineering
analysis. If a new or unexpected aqueous waste is generated,
this waste must be added to the initial report and included
in the facility's determination of TAB. Wastes that are
generated infrequently or intermittently are subject to
control under the rule if the TAB and benzene concentration
criteria are exceeded.
Question—What is the basis for the term "annual" in the
determination of TAB?
Answer—This determination is based on any 12 consecutive
months of operation. If the waste has not been generated for
a full year, the facility should provide its best estimate and
the basis for an annual projected quantity. If the waste is
generated periodically every few years, the estimate of
TAB should be based on the quantity produced during the
year with the highest generated quantity.
Question—Are organic wastes that contain less than 10 percent
water and are discharged to the wastewater system included
in the calculation of TAB? For example, drainings from
low points in lines or pumps that handle an organic product
(or even pure benzene) may enter the sewer system.
Answer—Although the discharge of organic products to the
sewer was not anticipated in the development of the
regulation, they should be included in the calculation of
TAB because once they enter the wastewater treatment
system and are mixed with wastewater, they become
aqueous wastes (10 percent or more water). Theoretically,
the benzene in the organic waste should be counted toward
the TAB if the organic waste is mixed with the water or
other waste and the resulting mixture has a water content
of 10 percenter more. Because this would be difficult, two
other options are to (1) include the benzene in the organic
waste at its point of generation or (2) measure the benzene
in the combined waste at the oil-water separator and
include any benzene lost prior to the separator.
Question—Are process wastewaters that qualify for the low
flow cutoff (0.02 L/min or 10 Mg/yr) in Section 61.342
(c)(3) included in determining the TAB for the facility?
Answer—Yes, all benzene-containing wastes managed at a
facility are included in determining the facility's TAB.
Question—Is the benzene in wastewater discharged from a
facility counted in the determination of TAB?
Answer—The quantity of benzene in the wastewater discharge
is not counted unless the discharge is the point of generation
for the waste. Facilities should avoid double counting, such
as adding the quantity at the point of generation in the
process to the quantity that is eventually discharged.
Question—Is the determination of flow-weighted annual
average water content (for comparison to a value of 10
percent) based on percent by volume or by weight?
Answer—Aqueous wastes are those that contain 10 percent or
more water by volume as total water. This has been
clarified in a Federal Register notice (55 FR 37230).
Question—When are controls required for new sources?
Answer—Applicability determinations are made on a facility
basis (entire geographical plant site). A new facility must
be in compliance with the regulation at startup. Benzene-
containing wastes managed in a new unit at an existing
facility above the 10-Mg/yrTAB cutoff must be controlled
by March 7,1992.
Question—Do all chemical plants, petroleum refineries, coke
by-product recovery plants, and commercial hazardous
waste facilities have to submit an initial report of their
determination of TAB, even if they do not use or produce
benzene or manage wastes that contain benzene?
A nswer—Yes. All facilities in these four affected industries are
subject to at least a one-time reporting requirement of
TAB. If the plant does not use or produce benzene, if it is
present only in small quantities, or if no wastes containing
benzene are managed, the initial report should state this
clearly. Whether waste streams should be controlled is
determined by the TAB and benzene concentration data
presented in the report.
Question—What waste streams must be included in the initial
report of TAB determinations (due June 5, 1990), what
accuracy is required, can it be amended, and should controls
be identified?
Answer—These questions arose because some facilities have
hundreds of waste streams, many of which have not been
measured for benzene quantity or concentration, and their
data collection effort may not be completed within the 90-
day period. A clarification has been published in the
Federal Register (55 FR 37230). The purpose of the initial
report is to identify facilities subject to the control
requirements, to identify which streams must be controlled,
79
-------
and to provide the basis for exemption of streams. There
are situations where knowledge of the waste could be the
basis for the estimates. Knowledge of waste could bebased
on engineering analyses, material balances, similarity of
streams, purchase records, etc. For example, wastes that do
not contact materials containing benzene do need not to be
listed. When new or more accurate information is obtained
ortlieprocessisredesigned.aresubmittalofthereportmay
be appropriate. Controls do not need to be identified in the
initial report; however, controls must be in place by the
March 7,1992, compliance date.
Question—If a facility hardpipes several waste streams to a
single point or location, are they required to measure each
individual waste stream at the point of generation or can
they measure the flow and concentration of the combined
stream? When are controls required for mixed wastes?
Answer—The ruledoes not require measurement at the pointof
generation. Consequently, the facility can measure the
combined stream and, coupled with other knowledge of the
individual processes or streams, estimate the flow and
concentration of individual streamsatthepointof generation
to calculate the TAB.
Process wastewater, which is defined in the rule and
specifically excludes certain wastes, may be excluded
from the control requirements under certain conditions,
even if it is a mixture that contains individual streams with
IQppmormore.Therequirementfor the process wastewater
exclusion is that the TAB in process wastewater be less
than 1 Mg/yr for the sum of (1) the TAB in untreated
streams at the point of generation and (2) the TAB in
untreated streams at the exit to the treatment unit.
There is also an alternative standard that addresses the
mixing of waste streams in a wastewater treatment system.
The wastewater treatment units handling the mixture must
be controlled until both (1) the waste entering an
uncontrolled unit is less than 10 ppm and (2) the TAB first
entering an uncontrolled unit is less than 1 Mg/yr. The TAB
entering an enhanced biodegradation unit is excluded from
this 1-Mg/yr determination. In other words, controls would
not be required on the enhanced biodegradation unit unless
the benzene concentration entering the unit is 10 ppm or
higher.
Question—Are controls for intermediate product tanks and day
tanks required under the rule?
Answer—No. The rule does not require controls for tanks that
manage products or intermediates. The rule applies only to
tanks that manage wastes containing benzene. However,
benzene wastes could be generalied from these tanks (as
from water drawdown), and these wastes could be subject
to control under the rule.
Question—Does the rule require water seals on the junction
box vent?
Answer—No. This has been clarified in a Federal Register
notice (55 FR 37230) to indicate that water seals are
required on the junction box and not on the vent The
purpose is to isolate the junction box to prevent wind or
induced air drafts from sweeping through the wastewater
collection system.
Question—Must the three samples required in Section 61.355
(c)(2)(i) be collected at different times or can they be
collected at the same time?
Answer—The rule does not specify a time between samples.
The applicable requirement is that the samples be
representative of the waste that is being analyzed.
80
-------
Chapter 10
Case Study:
Application of Benzene Waste Operations NESHAP to
Wastewater Treatment Systems
NOTE: Since the time the workshops were given, EPA has determined that clarifica-
tions to the Benzene Waste Operations NESHAP are required. Revisions to the rule
were proposed March 5, 1992 (57 FR 8017). Thus interpretations given during the
workshop may have changed. For the latest interpretation, contact Bob Lucas,
Emissions Standards Division, OAQPS (919) 541-0884.
Overview
Examples of the application of the National Emission
Standard for Benzene Waste Operations (40 CFR 61 Subpart
EF) to wastewater treatment systems are provided in this case
study. The standards for wastewater treatment systems that
manage and treat aggregated or mixed waste streams are
reviewed using some simple examples. A case study problem
is then presented to illustrate the application of the standard to
a "real world" wastewater treatment system at a petroleum
refinery.
Standards for Wastewater Treatment
Systems
The Benzene Waste Operations NESHAP requires own-
ers and operators of affected facilities at which the total
annual benzene quantity from the facility waste is equal to or
greater than 10 Mg/yr to remove or destroy benzene contained
in certain waste streams using a treatment process or waste-
water treatment system. Section 61.348 of the rule establishes
the treatment standards for treatment processes or wastewater
treatment systems. These standards require that if an owner or
operator chooses to aggregate or mix waste streams to facili-
tate treatment in a wastewater treatment system, the waste
streams must be treated in a wastewater treatment system that
meets special requirements. Each waste management unit that
comprises the wastewater treatment systems at the facility
must use the appropriate emission controls as specified under
Sections 61.343 through 61.347 until both of the following
conditions are met:
1. The waste entering an uncontrolled unit is less than 10
ppmw benzene; and
2. The total facility-wide wastewater treatment system an-
nual benzene quantity first entering any uncontrolled unit
is less than 1 Mg/yr.
Application of Basic Standards
The application of the basic standards is illustrated in
Figure 10-1. The drainage system, the oil/water separator, and
the dissolved air flotation (DAF) unit shown in Figure 10-1
require controls because they receive waste with benzene
concentrations of 10 ppmw or higher. The next three units
require controls because even though the benzene concentra-
tion is below 10 ppmw, the mass flow rate of benzene (i.e., the
annual benzene quantity) entering the units is greater than 1
Mg/yr.
Enhanced Biodegradation Units
One minor exclusion to the 1 Mg/yr benzene quantity
limit is: The benzene quantity entering an "enhanced biodeg-
radation" unit from the total annual benzene quantity inven-
tory for the wastewater treatment system is excluded if the
enhanced biodegradation unit is the first exempt unit. Section
61.348(b)(2)(ii)(B) provides guidelines regarding operating
conditions for what is defined as an "enhanced biodegrada-
tion" unit. These guidelines basically describe the operation
of a conventional activated sludge wastewater treatment pro-
cess. Activated sludge systems with benzene concentrations
of 10 ppmw or higher in any influent stream will still require
controls, but, if the benzene concentration is less than 10
ppmw, the annual benzene quantity entering an activated
sludge system does not count towards the 1 Mg/yr control
limit. Therefore, if we replace the surface impoundment in
Figure 10-1 with an activated sludge system (refer to Figure
10-2), no controls are required after the equalization basin.
Multiple Wastewater Treatment Systems
The 1 Mg/yr of benzene control limit pertains to the total
annual benzene quantity of the facility's wastewater treatment
system and not to the annual benzene quantity of a single
waste stream. For example, referring to Figure 10-3, Equal-
ization Basin #1 has an annual benzene quantity of 0.8 Mg/yr
while the groundwater waste stream entering Equalization
Basin #2 has an annual benzene quantity of 0.6 Mg/yr. In a
single train system, these equalization basins would not re-
quire controls. However the cumulative or total annual ben-
zene quantities for the uncontrolled units in this dual train
facility is 1.4 Mg/yr, which exceeds the 1.0 Mg/yr control
limit Therefore, one of the equalization basins in Figure 10-3
81
-------
Drainage System
„_..,_ HwtMWIMrJM^
,.«.,gff»i,p.i'
jTrfe,
hi
t-*
fesfe
Rainwater/Runoff
Drainage System:
0.004 Mg/yr; 0.02 ppmw
Legend
D Indicates Unit Not Requiring Controls
" under 40 CFR 61 Subpart FF
r-g _ Indicates Unit Requiring Controls because
"^ " Benzene Concentration Exceeds 10 ppm
rrm Indicates Unit Requiring Controls because
•222 " Mass Flow Rate of Benzene Exceeds 1 Mg/yr
Discharge
0.014 Mg/yr
Figure 10-1. Wastewater treatment system showing benzene concentrations and flow rates: Example 1.
must be controlled. No requirement is provided in the rule that
determines which basin is controlled since controlling either
basin reduces the total annual benzene quantity in the uncon-
trolled units to less than 1 Mg/yr. Therefore, to comply with
the rule, the facility owner or operator can choose which of
the equalization basins is controlled as is shown in Figures 10-
3a and 10-3b. Note that if Equalization Basin #2 is selected to
be controlled, the groundwater drainage system must also be
controlled.
Case Study Problem:
Application of Benzene Waste Operations
NESHAP to Wastewater Treatment Systems
The ABC Oil Company operates a refinery that is deter-
mined to have a facility total annual benzene (TAB) quantity
greater than 10 Mg/yr, and is therefore required to treat and
control certain benzene-containing waste streams at the refin-
ery to comply with the National Emission Standard for Ben-
zene Waste Operations (40 CFR 61 Subpart FF). Individual
process wastewater streams, product tank drawdown streams,
and landfill leachate streams generated by refinery processes
are collected in the refinery's drain systems for the purpose of
managing these wastewaters in a central wastewater treatment
system. Wastewaters that have an annual average benzene
concentrations above 10 ppmw are mixed with wastewaters
that have an annual average benzene concentrations below 10
ppmw in the refinery drain systems. Wastewater containing
hydrogen sulfides is first treated in a sour water stripper to
remove the hydrogen sulfides before the wastewater is mixed
v.-iili other wastewaters.
A flow diagram of the ABC Oil Refinery wastewater
treatment system is shown in Figure 10-4. The annual average
benzene concentration and annual benzene quantity for each
wastewater stream are identified on the figure. To comply
with the treatment standards under Section 61.348 of the rule,
the refinery manager has decided to treat the benzene-contain-
ing wastewater streams using the refinery's existing wastewa-
ter treatment system. The refinery manager has asked you to
determine which units comprising the wastewater treatment
system are required to use controls in accordance with the
rule. Refer to Table 10-1 for the problem and Table 10-2 for
the solution.
Under Section 61.348(b) of the Benzene Waste Opera-
tions NESHAP, special requirements apply to a wastewater
treatment system in which wastewater streams having annual
average benzene concentrations of 10 ppmw or more are
mixed with wastewaters having annual average benzene con-
centrations below 10 ppmw. The waste management units
handling these mixed wastewater streams are required to use
controls except for those units that meet two conditions: (1)
the annual average benzene concentration of the waste enter-
ing the unit is less than 10 ppmw; (2) the total annual benzene
(TAB) quantity in the wastewaters first entering all affected
uncontrolled units comprising wastewater treatment systems
facility-wide is less than 1 Mg/yr. The wastewater treatment
system configuration used for the case study problem is
shown in Figure 10-4. The same configuration showing the
case study solution is shown in Figure 10-5. A discussion of
the reasons why each unit shown in the figures is or is not
required to use controls is presented below.
82
-------
Drainage System
» !&!>!'..''!''!
Rainwater/Runoff
Drainage System:
j 0.004 Mg/yr; 0.02 ppmw
0.09 Mg/yr;
i_0.06 ppmw
Legend
I _ Indicates Unit Not Requiring Controls
I " under 40 CFR 61 Subpart FF
| _ Indicates Unit Requiring Controls because
' " Benzene Concentration Exceeds 10 ppm
i m Indicates Unit Requiring Controls because
I = Mass Flow Rate of Benzene Exceeds 1 Mg/yr
Figure 10-2. Wastewater treatment system showing benzene concentrations and flow rates: Example 2.
Discharge
0.014 Mg/yr
Drainage System
| Product |[
1 Tankage
Process
Units
Leachate
Ground-
water
=:
i — »
!
16 Mg/yr; f
1 0 ppmw. I
i
8 Mg/yr;
Oil/Water 5 ppmw [
Separator *
1
•
,
0.6 Mg/yr
0.6 ppmw
Equalization
Basin #2
i
0.5 Mg/yr; o
0.5 ppmw Activated rj
Tank
0.8 Mg/yr;
JAF 0.5 ppmw
Jnit *
Equalization
Basin #1
0.5 Mg/yr;
0.3 ppmw
i
07 Mg/yr; , . 0.008 Mg/yr;
02 ppmw f X 0.003 ppmw
^r
Return Sludge: 1
Disc
-
large
0.008 Mg/yr; 0.01 ppmw
Figure 10-3. Wastewater treatment system showing benzene concentrations and flow rates: Example 3.
83
-------
Drainage System
JWmmrrp
jhs ^
Process
Units
s -^
?
t^rr*!
p"* **^'
&"»*" •* •"*•» ;
t*r-j
ls™->
3f*~.» "
t ^"t
i| ..t,. .... -^
L .,
WMW* i "rrrr1:1;
:J«?^ : ,,cj»wsSft •
3 /t ssps^; '
0.008 Mg/yr; 0.01 ppmw
Q » Indicates Unit Not Requiring Controls under 40 CFR 61 Subpart FF
{TTJ. Indicates Unit Requiring Controls because Benzene Concentration Exceeds 10 ppm
HJ « Indicates Unit Requiring Controls because Benzene Mass Flow Rate Exceeds 1 Mg/yr
H " Indicates Unit Requiring Controls because Facility-Wide Uncontrolled Benzene Quantity Exceeds 1 Mg/yr
Figure 10-3a. Wastowater treatment system showing benzene concentrations and flow rates: Example 3; Solution A.
Drainage System
Discharge
0.008 Mg/yr; 0.01 ppmw
"1 - Indicates Unit Not Requiring Controls under 40 CFR 61 Subpart FF
]] « Indicates Unit Requiring Controls because Benzene Concentration Exceeds 10 ppm
j| - Indicates Unit Requiring Controls because Benzene Mass Flow Rate Exceeds 1 Mg/yr
3 " Indicates Unit Requiring Controls because Facility-Wide Uncontrolled Benzene Quantity Exceeds 1 Mg/yr
Figure 10-3b. Wastewater treatment system showing benzene concentrations and flow rates: Example 3; Solution B.
84
-------
Refinery
Processes
Process
Wastewater
Tank
Drawdown
Landfill
Leachate
V J
^-
301 Mg/yr
, 100 ppmw
1
Drain
Systems
i
3
Oil/Wa
Separ;
ter
Jtor
23 Mg/yr
10 ppmw,
4
DAF
Unit
7 Mg/yr f \
Sppmw /.A
V Clarifier /
6 Mg/yr I
2.5 ppmw w _
L
1 Mg/yr
Sppmw
2
Sour
Water
Stripper
6
Equalization
Basin
0.8 Mg/yr
Sppmw
hw
0
2
1.2 M
2ppr
5 Mg/yr
2 ppmw
9
Trirk
Fill
2 Mg/yr
ppmw
\
t
g/yr
nw
ling
er
(
7
Activated
Sludge
Tank
/^N
10
Clarifier
S. >
1.4 Mg/yr 4
' 2 ppmw J
L
1 Mg/yr / \
0.3 ppmw / 8 \
\ Clarifier /
V 0.75 Mg/yr o.3 Mg/yr
\ 1 ppmw o.1 ppmw
/ 1.05 Mg/yr
0.4 ppmw
0.75 Mg/yr
n .. , . 0.2 ppmw
Polishing
Discharge
Figure 10-4.
ABC Oil Refinery wastewater treatment system—case study problem. (Annual average benzene concentration and
annual benzene quantity shown for each wastewater stream.)
B.
C.
D.
Table 10-1. Case Study Problem
Possible answers for each waste management unit are:
A. No controls required.
Controls required: Annual average benzene concentration
entering the unit is 10 ppmw or more.
Controls required: Annual benzene quantity entering the unit is
1 Mg/yr or more.
Controls required: Total annual benzene (TAB) quantity first
entering uncontrolled waste management units comprising the
refinery wastewater treatment system is 1 Mg/yr or more.
For each waste management unit shown on Figure 10-4, circle the
letter or letters corresponding to all correct answers for the unit (more
than one answer may be correct for a particular unit).
Waste Management Unit
1. Drain Systems
2. Sour Water Stripper
3. Oil/Water Separator
4. DAF Unit
5. Primary Clarifier
6. Equalization Basin
7. Activated Sludge Tank
8. Secondary Clarifier
9. Trickling Filter
10. Clarifier
11. Polishing Pond
Answer
A
A
A
A
A
A
A
A
A
A
A
B
B
B
B
B
B
B
B
B
B
B
C
C
C
C
C
C
C
C
C
C
C
D
D
D
D
D
D
D
D
D
D
D
Drain Systems
The refinery drain systems combine wastewaters having
annual average benzene concentrations above 10 ppmw with
wastewaters having annual average benzene concentrations
below 10 ppmw. This results in three mixed wastewater
streams: a stream having an annual average benzene concen-
tration of 100 ppmw and annual benzene quantity of 301 Mg/
yr; a stream having an annual average benzene concentration
of 8 ppmw and annual benzene quantity of 0.8 Mg/yr; and a
stream having an annual average benzene concentration of 2
ppmw and annual benzene quantity of 1.2 Mg/yr. At this point
in the analysis, none of the waste'management units are
controlled under the rule, so the TAB quantity for the refinery
wastewater treatment system is 303 Mg/yr (calculation of this
value is discussed below under the oil/water separator unit).
Control requirements for drain systems are specified in Sec-
tion 61.346 of the rule. Thus, the drain systems are required to
use controls because the conditions specified in answers "b,"
"c," and "d" are not met.
Sour Water Stripper
For the purpose of implementing the Benzene Waste
Operations NESHAP, EPA has specified that, for a sour water
stripper unit, the determination of the flow-weighted annual
average benzene concentration shall be made at the exit to the
unit A "sour water stripper" must be controlled to meet the
85
-------
Table 10-2. Case Study Solution
Possible answers for each waste management unit are
A. No controls required.
B. Controls required: Annual average benzene concen-
tration entering the unit is 10 ppmw or more.
C. Controls required: Annual benzene quantity entering
the unit is 1 Mg/yr or more.
D. Controls required: Total annual benzene (TAB)
quantity first entering uncontrolled waste manage-
ment units comprising the refinery wastewater
treatment system is 1 Mg/yr or more.
For oach waste management unit shown on the figure, the
correct answers are circled below.
Waste Management Unit
1. Drain Systems
2. Sour Water Stripper
3. Oil/Water Separator
4. DAF Unit
5. Primary Clarifier
6. Equalization Basin
7. Activated Sludge Tank
8, Secondary Clarifier
9. Trickling Filter
10. Clarifier
11. Polishing Pond
BCD
definition in the rule, i.e., it must be "operated in such a
manner that the offgases are sent to a sulfur recovery unit,
processing unit, incinerator, flare, or other combustion de-
vice." Consequently, none of the listed answers are appropri-
ate. Controls are required, but not because of the reasons listed
in"b,""c,"or"d."
Oil/Water Separator
The annual average benzene concentration of the waste
entering the oil/water separator is greater than 10 ppmw (100
ppmw). The annual benzene quantity in the waste entering the
unit is greater than 1 Mg/yr (301 Mg/yr). Thus, neither of the
two conditions required for an exemption from controls is
met. At this point in the analysis for an actual facility, you
would conclude that the oil/water separator requires controls
because it does not meet either condition, and then move on to
the next downstream unit. However, for the purpose of this
case study problem, we will also determine the TAB quantity
first entering the uncontrolled waste management units com-
prising the refinery wastewater treatment system from the
inlet to the oil/water separator.
The TAB quantity is calculated by summing the indi-
vidual waste stream annual benzene quantities for each loca-
tion where a waste stream first enters an affected uncontrolled
waste management unit that is included in the facility waste-
water treatment system. Assuming that Unit 3 and the remain-
ing units (i.e., Units 4 through 11) are uncontrolled, the TAB
quantity is then calculated by summing the annual benzene
quantity in three wastewater streams: (1) the stream flowing
directly from the drain system to the oil/water separator (301
Mg/yr); (2) the stream flowing directly from the drain system
to the trickling filter (0.8 Mg/yr); and (3) the stream flowing
directly from the drain system to the clarifier (1.2 Mg/yr). The
TAB quantity is calculated to be 303 Mg/yr which is well
above the 1 Mg/yr limit Thus, the oil/water separator is
required to use controls because the conditions specified in
answers "c," and "d" are not met
DAF Unit
The annual average benzene concentration of the waste
entering the DAF unit is equal to 10 ppmw. Remember that
the rule requires the annual average benzene concentration of
the waste entering the unit to be less than 10 ppmw as one of
the conditions to be met for the exemption from controls. The
annual benzene quantity of the waste entering the unit is
greater than 1 Mg/yr (23 Mg/yr). Assuming at this step in the
analysis that Unit 4 and the remaining units (i.e., Units 5
through 11) are uncontrolled, the TAB quantity that would be
managed in the uncontrolled waste management units is cal-
culated to be 25 Mg/yr. Thus, the DAF unit is required to use
controls because the conditions specified in answers "c," and
"d" are not met.
Primary Clarifier
The annual average benzene concentration of the waste
entering the primary clarifier unit is less than 10 ppmw (3
ppmw). However, the annual benzene quantity of the waste
entering the unit is greater than 1 Mg/yr (7 Mg/yr). Assuming
at this step in the analysis that Unit 5 and the remaining units
(i.e., Units 6 through 11) are uncontrolled, the TAB quantity
that would be managed in the uncontrolled waste management
units is calculated to be 9 Mg/yr. Thus, the primary clarifier is
required to use controls because the conditions specified in
answers "c," and "d" are not met.
Equalization Basin
The equalization basin only receives wastewater from the
primary clarifier. Consequently, the annual average benzene
concentration of the waste entering the unit remains less than
10 ppmw (2.5 ppmw). However, the annual benzene quantity
of the waste entering the unit still is greater than 1 Mg/yr (6
Mg/yr). Assuming at this step in the analysis that Unit 6 and
the remaining units (i.e., Units 7 through 11) are uncontrolled,
the TAB quantity that would be managed in the uncontrolled
waste management units is calculated to be 8 Mg/yr. Thus, the
equalization basin is required to use controls because the
conditions specified in answers "c," and "d" are not met.
Activated Sludge Tank
The activated sludge tank is considered to be an "en-
hanced biodegradation unit" in accordance with Section
61.348(b)(2)(ii)(B) of the rule. This section specifies that the
annual benzene quantity managed or treated in an enhanced
biodegradation unit is not included in the calculation of the
TAB quantity if the enhanced biodegradation unit is the first
uncontrolled unit in which the waste is managed or treated.
This means that for the purpose of calculating the TAB
quantity, the annual benzene quantity entering the enhanced
biodegradation unit is set to 0 Mg/yr if the annual average
86
-------
301 Mg/yr
100 ppmw
Water
VVStripperVy
'////7///S
Mg/yr
.5 ppmw ^
r
jirj"!ii. s-,! ="%';
\ML. I$;Q\? '";fe;(
tir'Equaftzaliofj'.:''
'iiJiir BaSip^ ^i'
:•' fjvii'i^.'jri vj..j
5 Mg/yr
2 ppmw
7
Activated
Sludge
Tank
1 Mg/yr /
0.3 ppmw / 8
\ Clari
0.8 Mg/yr
8 ppmw
jm,..T,.>H1., =
••.A,,,' I"?!' ,i'i
A -v^g !"'l,i"H
prickling-^
,!*. rt^jjf. •».
f"1 f-1;.
0.75 Mg/yr
1 ppmw
0.3 Mg/yr
0.1 ppmw
1.05 Mg/yr
0.4 ppmw
[j, j Controls Required On Unit
[~~| No Controls Required On Unit
[^ Must Be Controlled to Meet Rule Definition (see text)
Figure 10-5. ABC Oil Refinery wastewater treatment system—case study solution.
11
Polishing
Pond
0.75 Mg/yr
0.2 ppmw
Discharge
benzene concentration of the waste entering the unit is less
than 10 ppmw. For the case study problem, the annual average
benzene concentration of the waste entering the activated
sludge tank is 2 ppmw. Even though the actual annual ben-
zene quantity of the waste entering the unit is greater than 1
Mg/yr (5 Mg/yr), the TAB quantity condition that the up-
stream units must meet in order to be exempted from using
controls is not applicable to the activated sludge tank because
it is an enhanced biodegradation unit in which the annual
average benzene concentration of the waste entering the unit
is less than 10 ppmw. Therefore, the activated sludge unit is
not required to use controls (answer "a").
Secondary Clarifier
The secondary clarifier only receives wastewater from
the activated sludge tank. As discussed above, the activated
sludge unit is an enhanced biodegradation unit which is
exempt from having to use controls. For the purpose of
calculating the TAB quantity, the annual benzene quantity
entering the activated sludge tank is set to 0 Mg/yr. Conse-
quently, it must follow that the wastewater stream entering the
secondary clarifier is also set to 0 Mg/yr. Even though the
annual benzene quantity of the waste entering tine secondary
clarifier is equal to 1 Mg/yr, the TAB quantity condition is not
applicable to this unit because all of the waste managed in the
secondary clarifier is received from an uncontrolled enhanced
biodegradation unit. Thus, the secondary clarifier is not re-
quired to use controls (answer "a").
Trickling Filter
The trickling filter is not considered to be an "enhanced
biodegradation unit" because it is a supported growth process
rather than a suspended growth process, and it does not
recycle biomass. Therefore, the trickling filter must meet both
the benzene concentration and TAB quantity conditions to be
exempt from having to use controls. The annual average
benzene concentration of the waste entering the trickling filter
is less than 10 ppmw (8 ppmw). Also, the annual benzene
quantity of the waste entering the unit is less than 1 Mg/yr (0.8
Mg/yr). Thus, whether or not the trickling filter is required to
use controls depends on the TAB quantity first entering the
uncontrolled waste management units comprising the refinery
wastewater treatment system.
The TAB quantity is calculated based on the annual
benzene entering Units 9, 10, and 11 and the decision as to
which of these units will be controlled. As discussed under the
activated sludge tank unit, Unit 7 does not require controls
and, for the purpose of calculating the TAB quantity, the
annual benzene quantity entering the activated sludge tank is
87
-------
set to 0 Mg/yr. Assuming that Units 9 and 10 are uncontrolled,
the TAB quantity is calculated to be 2.0 Mg/yr by summing
the annual benzene quantity entering the trickling filter (0.8
Mg/yr) plus the annual benzene quantity entering the clarifier
directly from the drain system (1.2 Mg/yr). Assuming that
Units 9 and 11 are uncontrolled, the TAB quantity is calcu-
lated to be 1.55 Mg/yr by summing the annual benzene
quantity entering the trickling filter (0.8 Mg/yr) plus the
annual benzene quantity entering the polishing pond from the
clarifier (0.75 Mg/yr—determination of this value is dis-
cussed under the polishing pond unit). For either assumption,
the TAB quantity is calculated to be greater than 1 Mg/yr.
Thus, for the particular set of benzene quantities selected for
the case study problem, the trickling filter is required to use
controls because the condition specified in answer "d" is not
met.
Clarifier
The annual average benzene concentration of the waste
entering the clarifier is less than 10 ppmw (2 ppmw). How-
ever, the annual benzene quantity of the waste entering the
unit is greater than 1 Mg/yr (1.4 Mg/yr) as a result of the
mixing of the waste stream from the trickling filter with a
waste stream directly from the drain systems. Knowing at this
step in the analysis that Unit 7 is uncontrolled and assuming
that Units 10 and 11 are uncontrolled, the TAB quantity that
would be managed in uncontrolled waste management units is
calculated to be 1.4 Mg/yr (the sum of the annual benzene
quantities entering the activated sludge tank, which is set to 0
Mg/yr, plus the clarifier). Thus, the clarifier is required to use
controls because the conditions specified in answers "c" and
"d" are not met.
Polishing Pond
Two wastewater streams also mixed together prior to
entering the polishing pond; one stream from the secondary
clarifier and one stream from the clarifier. The annual average
benzene concentration of the waste entering the polishing
pond is less than 10 ppmw. The annual benzene quantity in
the wastewater stream from the clarifier is 0.75 Mg/yr. The
annual benzene quantity in the wastewater stream from the
secondary clarifier is 0.3 Mg/yr. However, for the purpose of
determining compliance with the rule, the annual benzene
quantity for the wastewater stream entering the secondary
clarifier is set to 0 Mg/yr (refer to the discussion for the
secondary clarifier unit). Consequently, it must follow that the
wastewater stream exiting the secondary clarifier is also set to
0 Mg/yr. Even though the total annual! benzene quantity of the
wastewater streams entering the polishing pond is actually
1.05 Mg/yr, the TAB quantity of the waste entering the unit is
calculated to be 0.75 Mg/yr for the purpose of determining
compliance with the rule. Thus, the TAB quantity of the waste
entering the polishing pond is less than 1 Mg/yr, and the unit
is not required to use controls (answer "a").
88
-------
Chapter 11
Case Study:
Process Vent Rule Applicability and Compliance
Process Vent Case Study—Review of
RCRA Air Emission Standard for Process
Vents Hazardous Waste TSDF Operations
Situation
The XYZ Manufacturing Company operates various
manufacturing processes that generate approximately 1,000
tons of hazardous waste per year. This qualifies the XYZ
Manufacturing Company as a large quantity generator under
RCRA. The facility is a RCRA TSDF operating under interim
status and has an on-site wastewater treatment system with a
National Pollution Discharge Elimination System (NPDES)
permit. As the owner/operator of the facility, you are required
to
1) determine the applicability of the RCRA air rules for
process vents (i.e., 40 CFR 265, Subpart AA) to the
hazardous waste management unit emission sources at the
facility,
2) determine compliance status of current process vent emis-
sions and emission controls in relation to the control
requirements in 40 CFR 265, Subpart AA,
3) determine what action can be taken to comply with the
regulation, if the emission reductions are required under
the process vents standards.
Determinations
1. Determine which process vents are subject to the require-
ments of Subpart AA and why. For each process vent
identified in Figures 11-1 and 11-2, circle all of the
following statements that are correct (Note: Some vents
will have more than one applicable statement; all relevant
and appropriate choices should be circled.)
a. Vent is a process vent associated with one of the
unit operations specified in the rule that man-
ages a hazardous waste with an organic concen-
tration greater than 10 ppmw and therefore is
subject to the requirements of Subpart AA.
b. Vent is not a process vent as defined in the rule
and therefore is not subject to the requirements
of Subpart AA.
The operation/process associated with the
vent is not one of the unit operations speci-
fied in Subpart AA applicability (Section
265.1030(b)),
or
The passage of gases (i.e., vent emissions)
into the atmosphere is not process-related.
For example, emissions are caused by tank
loading and unloading (working losses)
rather than the process or unit operation.
Comments
a. The process vent rules apply only to those waste manage-
ment units or unit operations that are specified in the
rules. Affected unit operations include: distillation, frac-
tionation, thin-film evaporation, solvent extraction, steam
stripping and air stripping.
Vents on control devices (e.g., condensers and carbon
adsorbers) and on tanks serving the affected unit opera-
tions (e.g., distillate receivers, bottoms receivers, surge
control tanks, decant separator tanks, or hot wells) are
also subject to the standards if emission from the process
are vented through them (e.g., uncondensed overhead
vapors from a distillation operation).
b. A process vent means any open-ended pipe or stack that
is vented to the atmosphere either directly, through a
vacuum-producing system, or through a tank or air pollu-
tion control device. Emissions (i.e., gases or fumes) must
be process-related, such as evaporation produced by heat-
ing or caused by mechanical means such as a vacuum-
producing system.
89
-------
Product
Manufacturing
Operations
Distillation^
Column
Solvent In
Solvent
Storage
Tank
Organic
To Manufacturing
Operations
taonoraunga 11 Layer
Hazardous T^ Waste yj
Wasto *•
(Hazardous
Plant (Waste
Wasto tutorage,
nk
gej
Aqueous
Layer
Storage|To
Manufacturing
Operations
Filter Cake
To Land Disposal
Key
fj Vent ID No.
ft Vent
Gf Condenser
— Gas Phase
— Liquid Phase
To WWT
(See Figure 11-2)
T
To WWT
(See Figure 11-2)
Note: Organic Concentration of all Streams (Unless Otherwise Noted): 1,000 - 900,000 ppmw
Organic Concentration of Wastewater Treatment (WWT) Plant Streams: <9 ppmw
Rgure 11-1. Facility XYZ case study.
c. Vent is not subject to the requirements of Sub-
part AA because the waste managed in the unit
has an organic concentration of less than 10
ppmw.
c. The process vent rules apply to affected units managing
hazardous waste with a total organic concentration of 10
ppmw or greater on an annual average basis. Units man-
aging wastes with an annual average of less than 10
ppmw are not subject to the rules.
90
-------
Hazardous Wastewater
(From Figure 11-1)
to WWT
Sludge
Holding
Tank
Plate and
Frame Filter
Press
Filter Cake
To Land Disposal
Key
Q Vent ID No.
(Q> Vent
Note: Organic Concentration of Wastewater Treatment (WWT) Plant Streams: < 9 ppmw
Figure 11-2. Case study of Facility XYZ Wastewater treatment plant (WWT) with NPDES permit.
d. Vent is not subject to the requkements of Sub-
part AA because the operation/process unit as-
sociated with the vent is not subject to RCRA
Subtitle C or is exempt from RCRA permitting.
Vent
No.
1
2
3
4
5
6
1
8
9
Answers .
a,b,c,d
a,b,c,d
a,b,c,d
a,b,c,d
a,b,c,d
a,b,c,d
a,b,c,d
a,b,c,d
a,b,c,d
Vent
No.
10
11
12
13
14
15
16
17
Answers
a,b,c,d
a,b,c,d
a,b,c,d
a,b,c,d
a,b,c,d
a,b,c,d
a,b,c,d
a,b,c,d
d. If the unit is exempt from RCRA Subtitle C, it is not
subject to the requirements of Subpart AA. Examples of
types of RCRA exempt units are listed below:
Units such as product (not hazardous waste)
distillation columns generating organic hazard-
ous waste still bottoms are not subject to the
standards while the wastes are in the product
distillation column unit.
Elementary neutralization and wastewater treat-
ment tanks as defined by 40 CFR 260.10.
Units managing Subtitle D wastes or nonhazard-
ous wastes.
• Generators that accumulate hazardous waste in
tanks and containers for 90 days or less.
91
-------
2. Calculate the total facility process vent emission rate
(ER).
Casel:
ER
ER
Total facility ER is equal to the sum of the emission rates
for all individual process vents located at the facility that are
subject to the requirements of Subpart AA.
Case 2:
T3O
UK
ER;
3. Based on the total facility process vent emission rate (ER)
calculated above (from summing appropriate individual
quantities given in Table 11-1), identify which course of
action, from among those listed below, is appropriate:
a No emission reduction required.
b. Reduce emissions from each individual process
vent by 95%.
c. Reduce total facility process vent emissions by
95%.
d. Control one or more vents to get below the
emission rate limits.
c. Reduce operating hours to get below the emis-
sion rate limits.
Recommended Control Action
Case 1:
Case 2:
After identifying all affected process vents, you must
determine whether the total facility affected process vent
emission rate is below the emission rale limits (see operating
data under #2 and compliance criteria given below.)
If the total facility process vent emission rate for hourly
or yearly emissions exceeds the limits in the regulation, action
must be taken to reduce emissions below the limits. If the
emission rate limits cannot be attained, total facility process
vent emissions must be reduced, by 95% or more through use
of a control device.
Emission Rate Limits (Compliance Criteria)
Total facility process vent emission rate must be below
the following emission rate limits:
Short Term - <1.4 kg/h (3 Ib/h) AND
Long Term - < 2.8 Mg/yr (3.1 short tons/yr)
Table 11-1. Process Vent Emission Rate (ER) and Operating Hour (OH) Data
Case 1:
Vontld* 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17
ER(lb/hr) 9.3 6.1 0.07 0.49 0.16 1.0 0.20 0.12 1.2 0.13 0.06 6.1 8.9 1.2 0.13 0.84 1.5
OH(hr/yr) 4160 4160 8760 2000 8760 2000 8760 2000 2000 8760 2000 4160 2000 2000 2000 4160 2000
ER(t0n/yr) 19.3 12.7 0.31 0.49 0.7 1.0 0.88 0.12 1.2 0.57 0.06 12.7 8.9 1.2 0.13 1.7 1.5
Caso2:
Vontld* 1 2 3 4 5 6 789 10 11 12 13 14 15 16 17
ER0Whf) 8.1 5.2 0.11 1.0 0.18 0.8 0.08 0.11 1.0 , 0.15 0.05 4.5 9.0 1.1 0.15 1.7 2.2
OH(hrfyr) 4160 4160 8760 4000 8760 4000 8760 2000 2000 8760 2000 4160 2000 2000 2000 4160 2000
ER(ton/yr) 16.8 10.8 0.48 2.0 0.79 1.5 0.35 0.11 1.0 0.66 0.05 9.3 9.0 1.1 0.15 3.5 2.2
A solution to the case study on RCRA air emission
standards for process vents is presented in Table 11-2, and a
discussion follows.
92
-------
Table 11-2. Review of RCRA Air Emission Standard for
Process Vents from Hazardous Waste TSDF
Operations—Case Study
Solution
1. Vent Answer
1—d 5—b 9—a 13—b,d 17—b,c,d
2—b 6—a 10—b 14—c,d
3—b 7—b,d 11—b 15—b,d
•4—a 8—a 12—b,d 16—c,d
2. Case 1:
n
ER Hourly = £ ERpVj =0.49 + 1.0 + 0.12 + 1.2 =
ER Annual = jT ERpVj =0.49 + 1.0 + 0.12 + 1.2 = 2.81 )b/hr
i=1
Case 2:
ER Hourly = £ ERpVj =1.0 + 0.8 + 0.11 + 1.0 = I 2.91 Ib/hr I
J J ^M_BMHHM»IHM«|JI
ER Annual = £ ERpVj =2.0 + 1.5+0.11 + 1.0=| 4,61 Ib/hr |
3. Case 1: Total Hourly Facility Emission = 2.81 Ibs/hr
Total Hourly Facility Emission Cutoff = 3 Ibs/hr
2.81 < 3; Total Hourly Facility Emission below cutoff
Total Annual Facility Emission = 2.81 tons/hr
Total Annual Facility Emission Cutoff = 3.1 short ton/yr
2.81 < 3.1; Total Annual Facility Emission below cutoff
(a) Total facility emissions are below emission rate limits,
therefore no further emission reduction required.
Case 2: Total Hourly Facility Emission = 2.91 Ibs/hr
Total Hourly Facility Emission Cutoff = 3 Ibs/hr
2.91 < 3; Total Hourly Facility Emission below cutoff
Total Annual Facility Emission = 4.61 tons/yr
Total Annual Facility Emission Cutoff = 3.1 short ton/yr
4.61 > 3.1; Total Annual Facility Emission above cutoff
(b), (c), (d), fe)
Total facility annual emissions are above the cutoff; can
reduce emissions from each individual process vent by
95%, reduce facility process vent emissions by 95%, or
control one or more vents to get the total facility process
vent emissions below the emission rate limits, or reduce
operating hours on affected units (e.g., by at least 50% on
vent 4 and 6) to get below the emission rate limits.
Discussion of Solutions to the Process
Vent Rule (Subpart A A)
Case Study
Applicability Determinations
Vent No. 1: d. This is a production unit, i.e., distillation
unit, that is part of the manufacturing operations. This unit is
generating an organic hazardous waste, the still bottoms.
However, under 40 CFR 261.4(c), a hazardous waste that is
generated in a manufacturing process unit is not subject to
regulation under Parts 262 through 265, 268, 270, 271, and
124 until it exits the unit in which it was generated, unless the
hazardous waste remains in the unit more than 90 days after
the unit ceases to be operated for manufacturing. Therefore,
because the unit is not subject to RCRA permitting, the vent
on this unit is not subject to the Subpart AA process vent
rules.
Vent No. 2: b. The vent on this decanter tank is not
subject to the Subpart A A rules because the vent is not a
process vent associated with one of the affected unit opera-
tions, i.e., distillation, fractionation, thin-film evaporation,
solvent extraction, or air or steam stripping.
Vent No. 3: b. The vent on this surge tank is not covered
by the Subpart AA. Although this tank is associated with (or a
part of) one of the affected unit operations, the vent on this
tank does not meet the definition of a process vent as specified
in the rule. This is because the emissions from the tank are not
process-related. Emissions from one of the affected unit op-
erations are not vented through this tank; emissions are work-
ing and breathing losses.
Vent No. 4: a. This vent is subject to Subpart A A. The
vent on this distillate receiver is a process vent associated with
a distillation column, one of the affected unit operations.
Overhead gases from the distillation column are sent to a
condenser, the condensed organic (liquid) and the uncondensed
vapors 90 to the distillate receiver where the uncondensed
gases are vented to the atmosphere. The emissions from this
vent are related directly to the distillation operation.
Vent No. 5: b. The vent on this storage tank, which holds
the hazardous waste after a portion of the waste has been
extracted, is not covered by the Subpart AA rules. Although
this tank is associated with (or a part of) one of the affected
unit operations, the vent on this tank does not meet the
definition of a process vent as contained in the rule. Emissions
from the tank are not process-related. As shown in Figure 11-
1, the solvent extraction operation is basically a liquid-liquid
extraction operation; no gases or vapors are generated nor is
any heat applied to the waste stream as is the case in distilla-
tion. Emissions from the tank are not process-related but are
working and breathing losses. If the hazardous waste stream
was heated in the process unit to enhance extraction and the
heated waste was stored in this tank at a temperature greater
than ambient, the argument could be made that the emissions
from the tank were indeed process-related. Therefore, the
vent, in the case where heat is applied, would be a process
vent associated with an affected unit operation and come
under the authority of Subpart AA.
Vent No. 6: a. This vent is subject to Subpart AA The
exhaust gases from the vacuum pump serving the batch still
are considered a process vent associated with a distillation
unit, one of the affected unit operations. Overhead gases from
the batch still pass through the condenser; the pump drawing a
vacuum on the condenser and distillate receiver is exhausting
uncondensed gases from the distillation operation to the atmo-
sphere. The emissions from this vent are related directly to the
distillation operation.
93
-------
Vent No. 7: b,.d. The vent on this storage tank, which
holds the liquid distillate recovered from the batch still opera-
tion, is not subject to Subpart AA. The vent on this tank does
not meet the definition of a process vent as specified in the
rule; emissions from this vent are not process-related. In
addition, under 40 CFR 261.3 (c)(2)(i), the definition of
hazardous waste, materials that are reclaimed from solid
waste and that are used beneficially, are not solid wastes and
hence arc not hazardous wastes unless the reclaimed material
is burned for energy recovery or used in a manner constituting
disposal. In this example, the distillate reclaimed in the distil-
lation operation is returned to or reused in the manufacturing
operation; therefore, the material stored in this tank is no
longer a hazardous waste, and as a result the tank is not
subject to regulation under RCRA Subtitle C.
Vent No. 8: a This vent is subject to Subpart AA. The
exhaust gases from the carbon adsorber serving the condenser
on the thin-film evaporator (TFE) are considered a process
vent associated with the TFE, one of the specified unit opera-
tions. Overhead gases from the TFE pass through the con-
denser; a portion of the uncondensed gases are directed to the
carbon adsorber which emits any unadsorbed gases to the
atmosphere. Emission from the control device are directly
related to the TFE operations.
Vent No. 9: a This vent is subject to Subpart AA. The
vent on this distillate receiver is a process vent associated with
the thin-film evaporator (TFE), one of the unit operations
affected by the process vent rules. Overhead gases from the
TFE are sent to a condenser; the condensed distillate (liquid)
and a portion of the uncondensed vapors from the TFE go to
the distillate receiver where the uncondensed gases are vented
to the atmosphere. The emission from this vent are related
directly to the TFE operation.
Vent No. 10: b. The vent on this storage tank, which
holds the liquid distillate recovered from the thin-film evapo-
rator, is not subject to Subpart AA. The vent does not meet the
definition of a process vent as specified in the rules; emissions
from the vent are not process-related. The losses from the tank
would be working and breathing losses.
Vent No. 11: b. The vent or exhaust gas from the boiler
used to burn the hazardous waste is not subject to Subpart AA,
the process vent rules. This boiler is not one of the unit
operations specified in the rule, i.e., distillation, fractionation,
thin-film evaporation, solvent extraction, and air and steam
stripping. Also, the boiler is not being used as a control device
to reduce emissions from an affected process vent. The boiler,
however, would likely be subject to other RCRA regulation
such as the recently promulgated final rule regulating the
burning of hazardous waste in boilers and industrial furnaces
(56 FR 7134, February 21,1991).
Vent No. 12: b,.d. The vent on the clarifier unit is not
subject to Subpart AA. This unit (i.e., a tank) is not one of the
unit operations specified in the rule; nor are emissions from an
affected process unit vented through this tank (i.e., the clari-
fier).
In addition, under 40 CFR 264.1(g)(6), 265.1(c)(10), and
270.1 (c)(2)(v) wastewater treatment units are not subject to
RCRA Subtitle C hazardous waste management standards
provided the unit is part of a wastewater treatment facility that
is subject to regulation under either Section 402 or Section
307(b) of the Clean Water Act. Accordingly, any hazardous
waste tank system that is used to store or treat wastewater that
is managed at an on-site wastewater treatment facility with a
National Pollution Discharge Elimination System (NPDES)
permit or that discharges to a Publicly Owned Treatment
Works (POTW is exempt from the RCRA regulations. In this
example, the facility has an NPDES wastewater permit as
indicated on Figure 11-2. The clarifier unit is a tank treating
wastewater (i.e., the aqueous layer from the decanter) that is
managed on-site; therefore this tank is exempt from the RCRA
regulations.
Vent No. 13: b,d. The vent on the enclosed plate and
frame filter press is not subject to Subpart AA. This unit does
not involve one of the unit operations specified in the rule.
Also, the filter press which meets the RCRA definition of a
tank can be considered a RCRA exempt wastewater treatment
tank (See Vent No. 12.)
Vent No. 14: c, d. This vent is not subject to Subpart AA.
Although the vent on the decanter is a process vent associated
with one of the specified unit operatioos (i.e., a steam strip-
per), the organic concentration of the waste managed in the
unit is less than the applicability criteria of 10 ppmw on an
annual average basis. In addition, the steam stripping column,
which meets the RCRA definition of a fcmk, can be considered
a RCRA exempt wastewater treatment tank (See Vent No.
12.)
Vent No. 15: b,.d. The vent on this storage tank is not
covered by Subpart AA because the vent is not a process vent
associated with one of the affected unit operations. In addi-
tion, under 40 CFR 262.34 generators that accumulate hazard-
ous wastes in tanks for 90 days or less are not subject to
RCRA permitting requirements for these tanks, provided they
comply with the provisions of 40 CFR 262.34. As noted
Figure 11-1, this is considered a generator's 90-day accumu-
lation tank and therefore is exempt from the RCRA rules.
(Note: EPA intends to modify this exemption at a later date.)
Vent No. 16: c,d. The vent on mis air stripper is not
subject to the RCRA process vent rules. Although the vent (or
air stripper exhaust) is a process vent associated with one of
the specified unit operations, the organic concentration of the
waste managed in the unit is less than the applicability criteria
of 10 ppmw on an annual average basis, as noted in Figure 11-
2. In addition, the air stripping column, which meets the
RCRA definition of a tank, can be considered a RCRA
exempt wastewater treatment tank (See Vent No. 12.)
Vent No. 17: b.c.d. The vent on the enclosed plate and
frame filter press is not subject to Subpart A A. This unit does
not involve one of the unit operations specified in the rules.
Also, the organic concentration of the waste managed in the
unit is less than the applicability criteria of 10 ppmw. In
addition, the filter press, which is a tank under RCRA, can be
considered a RCRA exempt wastewater treatment tank (See
Vent No. 12.)
94
-------
Chapter 12
Case Study:
Equipment Leaks Testing—EPA Method 21
As indicated in Table 12-1, this chapter is organized into
four areas. First the Method 21 requirements are described,
both for the instruments that are used for leak detection and
for the person operating the instrument. The second segment
of the chapter describes the various types of instruments that
can be used for leak detection and how they operate. Included
are highlights of an 11-minute training videotape describing
pre-use checks to be performed on the instruments before they
are taken into the field, a discussion of instrument calibration
and how response factors are used to select the correct instru-
ment for particular monitoring situations. The third part of the
chapter discusses field monitoring problems. This includes
highlights from a videotape lesson that describes some typical
problems related to field monitoring work, e.g., how to orient
the sampling probe and what happens if it is not done cor-
rectly. The fourth and last segment compares instruments that
can be used for this type of work.
Table 12-1. Overview
Method 21
Instruments and their operation
Field monitoring concerns
Comparison of available instruments
Method 21 Requirements
As directed by Subpart BB, Method 21 is used only to
determine whether or not equipment subject to the rules leaks.
Method 21 is not used for quantification of the emissions in
terms of pounds per hour or grams per second. Measurements
of concentrations are made, and if they exceed the leak
definition, that equipment is determined to be leaking and
must be repaired. The method was promulgated in Appendix
A of Part 60 of the Code of Federal Regulations and most
recently revised on June 22, 1990 (see Appendix A to this
chapter for revised method).
The method specifications require that the instruments
used for leak detection be capable of responding to specific
organic compounds. That is, compounds likely to be present
in the facility to be tested must be known in order to select an
instrument capable of responding to them.
The method also requires that the scale on the instrument
be readable to 2-1/2 percent of the leak concentration defini-
tion. For Subpart BB, that leak concentration definition is
10,000 ppm. That means the scale must be readable to the
nearest 500 ppm (±250 ppm). The sample gas flow rate for the
instruments used must be in the range of 0.1 to 3 L/min. The
revision in June 1990 reduced the minimum flow from 0.5
Lpm to 0.1 Lpm to allow some photoionization type analyzers
that did not previously meet the criteria to qualify.
The instruments that are used have to be rated intrinsi-
cally safe. Intrinsically safe means that they can be used in an
explosive environment without risk of setting off an explosion
that will destroy the instrument and the user.
To use an instrument in a specific monitoring situation,
the response factor of that instrument for the compounds that
may be leaking has to be less than 10. Response factors will be
discussed in more detail later in this section. The response
time of the instruments must be less than 30 seconds. This is
important because the facilities in which leaks are monitored
often contain hundreds of valves. The method requires that the
sampling probes be kept in the vicinity of a potentially leaking
source for up to twice the response time of the instrument in
order to determine if a leak is present. If you have an instru-
ment that responds in 30 seconds instead of one that responds
in 5 seconds, that may significantly prolong the inspection
work that you are doing.
The calibration precision, i.e., the repeatability of the
measurements, must be equal to or less than 10 percent of the
calibration gas concentration. Calibration gas concentration is
the leak definition concentration (10,000 ppm) so the preci-
sion of the instrument has to be repeatable within 1,000 ppm.
The calibration precision of the instrument, i.e., the repeat-
ability of the measurements, has to be checked at least once
every 3 months.
Response factors are needed for each compound that may
be present in a leak. Response times for the instruments must
be checked when you purchase the instrument and then any
time that modifications that could affect sample flow are
made to the instrument. For instance, changing the sampling
probe by making it longer may change response time. Adding
a glass wool plug at the end of the probe to keep paniculate
matter out of the sampling probe may also affect sample flow
rate. When such changes are made, the sample flow rate must
95
-------
be rcchecked and response time to make sure they comply
with the ranges specified by the method.
Instruments and Their Operation
Instrument Descriptions
Instruments generally used for this type of work and pre-
usc checks and calibrations are discussed in this segment. The
definition of response factor is presented and a number of
examples are given to show how response factors are used to
select the correct type of instrument.
Four types of portable organic analyzers can be used for
this work: Flame-ionizadon, catalytic combustion, photoion-
ization, and infrared. Although infrared devices can be used,
they are not typically used in this work.
A flow schematic of one type of flame-ionization ana-
lyzer is shown in Figure 12-1. The sample gas is drawn in
through the sampling probe where particle filter prevents
contamination of the sampling probe and internal plumbing
with particulates. The sample passes through a flow indicator
into the detector chamber. Hydrogen comes from an internal
fuel tank, passing through some pressure regulators, and
mixes with the sample gas stream, and the mixture is com-
busted in the detector chamber. On each side of the detector
chamber are sintered metal flame arresters that are part of the
intrinsically safe design of the instrument. They prevent flame
in the combustion chamber from escaping and igniting an
explosion in an area where an explosive gas mixture may be
present.
The combustion reaction in the detection chamber pro-
duces positive ions. The ion current is amplified to get a meter
reading that is proportional to the organic concentration in the
sample gas stream.
r
Figure 12-2 is a photograph of the front of one type of
flame-ionization analyzer.
The second type of instrument that could be used is a
photoionization analyzer. In this instrument, the organic va-
pors that are drawn into the sampling probe are exposed to a
source of ultraviolet light. That ultraviolet light causes the
.organic compounds present in the sample gas mixture to
ionize. When those ions are formed, they generate a current
that is amplified and produces a meter reading proportional to
the organic vapor concentration. Different organic compounds
ionize at different voltages. Lamps purchased for use in the
photoionization analyzers are available in several voltages.
The lamp voltage should be selected on the basis of the
compounds anticipated to be present. For example, this type
of analyzer does not respond to hexane or methane and
paraffinic type organic compounds at the lamp voltages typi-
cally available. It does respond very well to oxygenated or
halogenated compounds such as ketones, aldehydes, or chlori-
nated solvents, but certain of these compounds ionize more
readily than others. Thus, in some situations this instrument is
better than others for detecting organic vapor emissions.
Appendix B of the attachment to this session includes a
table that has response factors; the table also lists ionization
potentials for some organic compounds. This table can be
used to determine what voltage ultraviolet light to select. In
addition, the instrument manufacturer should have further
information on which to base a selection.
The lamp inside the analyzer and the window on the
surface of that lamp that needs to be cleaned after it has been
exposed to organic compounds for a period of time are shown
in Figure 12-3. Deposits will build up on the window which
I
Sintered
-Metal
Flame
Arresters
H2 Supply
Pressure Indicator
H2 Supply
Valve
Exhaust
Sample
Primary m
Filter _ If
Line \
Fitting VH
-i- JF
i now i-raie
Indicator
] Side
Filter and
p
Pack Assembly
Refill Valve -
Flow Restrictor_
. .... _. .
.Sl ' 'ng
t
T-
_/ Sample!
Sample Hose Umbilical
N In
|_JJord^&_Readou^AssernblyJ p^le ,
i Pick-Up Fixture j
Figure 12-1. Flow schematic of one type of flame-ionization analyzer.
96
-------
Figure 12-2. Photograph of the front of one type of flame-
ionization analyzer.
will have to be cleaned to maintain the instrument's sensitiv-
ity. It can be cleaned with the lamp in place.
This instrument is somewhat more compact than the
flame-ionization type analyzer. In this particular case, the
photoionization lamp is located in the box that contains the
meter.
Another design is shown in Figure 12-4 in which the
photoionization lamp is located on the end of an umbilical
cord. In this case, the lamp is outside the box that contains the
meter.
The third type, the catalytic combustion analyzer (Figure
12-5), is similar to the flame-ionization type detector in that
the sample gas drawn into the instrument is combusted (oxi-
dized) by a heated catalyst wire inside the instrument that
promotes the combustion reaction. When combustion takes
place, the resistance of the catalyst-coated wire changes, and
the resistance change is detected in the metering circuit That
change in resistance is proportional to the concentration of the
organic materials that are present in the sample gas stream.
One difference between the catalytic combustion ana-
lyzer and the flame-ionization analyzer is that no hydrogen
gas is supplied or required. The combustion reaction is pro-
moted through the presence of oxygen that is drawn with the
sample gas stream.
No hydrogen tank is inside this device as shown in Figure
12-5. This box is somewhat more compact than the flame-
ionization type device.
Daily Use Prechecks
This section describes some of the steps that should be
taken before the instrument is brought into the field. The
precheck list shown here is specifically for a flame-ionization
detector; the list may vary for other types of instruments.
Prechecks require only a modest amount of time, time
invested in conducting a precheck is well spent, since work
should not be attempted if the instrument is not functioning
properly or if it will fail soon after you begin. The following
instrument prechecks are recommended as a means of ensur-
ing adequate instrument performance during leak surveys:
Hydrogen Supply
Confirm sufficient hydrogen is present to fuel instrument.
(Note: Insufficient hydrogen pressure can result in erro-
neous readings.)
• Read pressure gauge ,
|!^S^SSS¥^SftiSSftfe&«o^&*vvCviAwi..- v- . 't' "* . "• **•** * !"
Figure 12-3. Lamp inside analyzer and window on surface of lamp.
97
-------
Figure 12-4. Photolontzatlon lamp on the end of an umbilical
cord.
Battery
Confirm battery is adequately charged. (Note: Failure to
adequately charge battery could lead to a deep discharge
necessitating installation of new batteries.)
Disconnect battery from external charger and
connect instrument gauge to instrument. Watch
for proper gauge response. Take a spare fully
charged battery to the inspection site.
Flame Arrester
Confirm the presence of the flame arresters before each
use to prevent hydrogen flame exposure to outside air.
(Note: Precheck is critical in preventing potential explo-
sive conditions.)
• Visually verify flame arrestors are in the proper
location.
Amplifier
Confirm amplifier electronic lin<;arity. (Note: Lack of
amplifier electronic linearity will result in erroneous read-
ings.)
Intrinsically Safe
.Model
I. S. (Intrinsically Safe) Battery Pack
0023-7354
Miniature Pump Assembly
0023-4491
Speaker
0038-4150
Standard Model: 6 Hi-Cad
Cells in Tubes
Terminal Block
0104-0696
Speed Nut
0002-3836
Chassis
Subassembly
0023-4633
. Tubing, 1/4
314-070-00
Vibration
Isolating
Receptacle
0023-4451
1/4-Turn
Fastener;
Retainer 0002-0054
Stud 0002-8-59
Reeiction Chamber
0023-4635
Figure 12-5. Catalytic combustion analyzer.
98
-------
• Turn on amplifier system allowing 10-minute
warmup. If linearity is adequate, move the cali-
bration knob to yield a reading of 10,000 ppm
with high calibration scale and 10 ppm with the
low switch. If linearity is not adequate, adjust
internal calibration.
Prefilter and Probe
Check prefilter and probe for contamination. (Note: Con-
tamination of probe or prefilter could affect instrument
performance.)
• Visually examine the probe for deposits of ma-
terial on the filter or organic deposit of moisture
on the probe;
Probe and Sample Gas Handling System
Confirm that no leaks are in the sample gas handling
system. (Note: Leaks could bias the instrument's re-
sponse low and even reduce the unit's capability to draw
fugitive gas into the probe.)
• .Turn pump on and briefly block the sample gas
line at various locations and listen for starved
pump sound. If not heard, air leak must be found
and eliminated.
Sample Flow Rate
Measure the sample gas flow rate into the probe and
conduct a leak check to confirm no infiltration at the top
of the rotameter. (Note: Leak could bias flow readings
low.)
• Attach a calibrated rotameter or a soap bubble
flowmeter to the probe and record flow rate in a
bound notebook.
Sample Valve to Gas Chromatograph (GC)
Column or Scrubbing Column
Confirm closure of valves that direct sample gas to GC
column or activated charcoal scrubbing column that are
not used in fugitive emissions testing. (Note: Opening
these valves will cause the VOC readings to suddenly
decrease to negligible levels.)
• Visually check valve buttons to verify they are
not depressed.
Instrument
Method 21 requires daily calibration of the instrument.
(Note: The readings after calibration are only a general
indication of the leak concentration unless you have
calibrated with the precise gas or gas mixture being
detected.)
• Calibration should be done with instrument un-
der a hood using either a gas cylinder standard
or a volatilized liquid mixture. Fill a 5-liter
Tedlar bag with calibration gas, then disconnect
bag from the regulator and connect to the instru-
ment probe. Due to short response time of units,
gauge should deflect within several seconds and
quickly reach the anticipated concentration
readily. If necessary, the calibration knob is
adjusted to give the calibration gas concentra-
tion.
Instrument
Recordkeeping of instrument's response time.
• At least quarterly, observe and record the re-
sponse time of the instrument. The procedure
mentioned directly above in calibrating should
be repeated at least three times and the time
required to reach 90 percent of the calibration
concentration recorded in a bound notebook.
The Subpart BB rules require that calibration be done
either with 10,000 ppm of methane in air or normal hexane in
air. Although not required by the method, calibration should
be done at 500 ppm, which for some of the equipment is the
concentration level below which no detectable emissions are
demonstrated (the readings must be less than 500 ppm above
background). Flame-ionization detectors and catalytic com-
, bustion analyzers should be calibrated with methane or hex-
ane in air. The photoionization analyzers do not respond well
to paraffinic type compounds, but, specifically, photoioniza-
tion analyzers cannot be calibrated with methane and hexane;
they must be calibrated with some other gas. Photoionization
analyzers are often calibrated with butadiene or benzene or
some other compound that may be present in the mixtures for
which leak monitoring would be attempted.
If a photoionization analyzer is selected, a conversion
factor must be developed to show the relationship between the
calibration of that instrument with whatever compound is
selected for the calibration and the readings that would be
Obtained if it were calibrated with methane and hexane.
Photoionization analyzers generally will not read beyond
the 1,000- to 2,000-ppm range of organic concentration. So, if
a photoionization analyzer is selected for a leak detection
survey, a dilution probe or some means must be used of
supplying a known amount of air to mix with the sample gas
stream when it is drawn into the instrument. That dilution
probe will reduce the concentration into the measurable range.
By knowing the dilution ratio for that probe and instrument,
the true reading may be determined.
Response Factors
Response factors in Method 21 are defined as the actual
concentration of a known gas sample divided by the meter
reading that is produced for that known gas sample on the
instrument after the instrument has been calibrated with the
selected calibration gas.
The next several tables show how to use response factors
to help choose the instrument to be used in a specific leak
monitoring situation. The first example (Table 12-2) is a
catalytic combustion analyzer exposed to a known concentra-
tion of 10,000 ppm of methanol vapors that have been made
up as a standard. After this instrument has been calibrated
with methane or hexane, a meter reading of 5,000 ppm is
produced when the instrument is exposed to the 10,000-ppm
concentration of methanol. So actual concentration divided by
meter reading gives a response factor of 2. Method 21 requires
99
-------
Table 12-2. Catalytic Combustion Analyzer Exposed to 10,000
ppm Molhanol Vapors
Table 12-5. Response Factors at Various Concentrations,
Example 1
Instrument
Organic vapor
Actual concentration
Motor reading
Response factor
Catalytic combustion
Methonal
10,000 ppm
5,000 ppm
2
that the response factor for the compounds for which you are
attempting to find leaks be less than 10. Thus, this instrument
would be acceptable for finding methanol leaks.
The second example (Table 12-3) is a flame-ionization
analyzer used to detect orthochlorotoluene vapors made up in
an actual concentration of 3,000 ppm. The meter, after the
instrument has been calibrated with methane or hexane, pro-
duced a reading of 6,000. Actual concentration divided by
meter reading is 0.5, obviously well below 10. This instru-
ment is sensitive to orthochlorotoluene vapors, more sensitive
to them than it is to methane. It is actually giving a higher
reading than the true concentration.
Table 12-3. Flame-lonlzation Analyzer Used to Detect
Orthochlorotoluene Vapors
Instrument
Organic vapor
Actual concentration
Motor reading
Response factor
Flame ionization
O-Chlorotoluene
3,028 ppm
6,056 ppm
0.5
In the third example, Table 12-4, a catalytic combustion
analyzer is being used for detection of tetrachloroethane va-
pors that are present in an actual concentration of 6,000 ppm.
The instrument reading of 430 shows the instrument is not
very sensitive to tetrachloroethane. The response factor is 14,
so the instrument would not be acceptable for monitoring
leaks of tetrachloroethane.
Table 12-4. Catalytic Combustion Analyzer Used to Detect
Tetrachloroethane Vapors
Instrument
Organic vapor
Actual concentration
Motor reading
Response factor
Catalytic combustion
1,1,2,2-Tetrachloroethane
5,980 ppm
427 ppm
14
The next three examples show that response factors can
vary with organic vapor concentration, so the response factor
determinations must be made at the leak definition level.
In the example shown in Table 12-5, methanol standards
were made up over a concentration range of 50 to 20,000 ppm,
and the response factors determined varied between 1.3 and
2.5. Some scatter exists, but the response is increased with
increasing concentration. All of these data show that the
Instrument
Organic vapor
Actual concentration
(ppm)
Caitalytic combustion
Methonal
Response factors
•50
500
2000
5000
10000
20000
1.7
1.4
1.'3
1.8
2.1
2.5
instrument would be acceptable to measure concentrations of
leaking vapors of methanol.
In Table 12-6, orthochlorotoluene standards in the con-
centration range of 200 to 3,100 ppm were made. The re-
sponse factors decrease slightly with increasing concentra-
tion. Two points are illustrated with this example; one is that
the response factors vary with concentration. The second is
that situations may exist in which obtaining a mixture of a
particular compound at 10,000 ppm is not possible. The
mixture may be made up in concentration levels that can be
achieved in the laboratory, over a concentration range, and
then a statistical method may be used to project what the
response factor would be at 10,000 ppm.
Table 12-6. Response Factors at Various Concentrations,
Example 2
Instrun
Organ'
Actual
(ppm
nent ^ Flame ionization
c vapor > O-Chiorotoluene
concentration >• Response factors
)
iV-.: 200-
: , 1500
3100
0.6
0.5
0.5
In the next example, Table 12-7, the catalytic combustion
analyzer with tetrachloroethane vapors is in the concentration
range of 210 to 1,453 ppm. The response factors at 210 and
572 ppm are around 8. Above 1,000 the response factors have
increased to 11. So at 10,000 ppm, you would project from
this information that it would not be an acceptable instrument
to use for detecting tetrachloroethane Leaks.
Table 12-7. Response Factors at Various Concentrations,
Example 3
Instrument
Organic vapor
Actual concentration
(ppm)
Catalytic combustion
1,1,2,2-Tetrachloroethane
Response factors
100
-------
Published response factor tables that are in Appendix B
give response factors at 10,000 ppm. A set of tables gives
response factors at 500 ppm as well. The calibration gas
selected, whether it is methane or hexane, may affect the value
of the response factor for a particular compound.
Response factors are used only to select the correct type
of instrument for a particular monitoring situation. Response
factors are not used to adjust meter readings obtained during
leak tests. Once the instrument selection is made, the readings
are taken exactly as they come off the meter. The only time
the meter readings would have to be adjusted is be when the
calibration gas used is different from the ones indicated by the
rules.
The method allows use of the published response factors
as a basis for demonstrating that the instrument selected is
acceptable. One problem with using published response fac-
tors is that data are not available for all organic compounds.
Only about 300 for which data are available to the public
actually have been tested. So, if working with compounds that
are not on the list of 300, response factors must be determined
experimentally. Another reason for the experimental determi-
nations is that variations exist between instruments of the
same type. In the next example a flame ionization analyzer is
being used to detect cyclohexanol vapors in the range of 200
to 1,200 ppm. Some slight differences in response factors
between the two units are evident. The trend would indicate
that at 10,000 ppm the response factors would be less than 10
(Table 12-8).
Table 12-8. Instrument Variations, Example 4
Instrument
Organic vapor
Actual concentration
(ppm)
Flame ionization
Cyclohexanol
Response factors
Unit #1 Unit #2
In the next example (Table 12-9), two catalytic combus-
tion instruments, supposedly identical, were used to detect
concentrations of meta-xylene over the range of 200 to 7,000
ppm. One unit gives response factors in the range of 1.5 to 2;
the other unit gives readings in the range of 3.5 to 37.9. This
Table 12-9. Instrument Variations, Example 5
Instrument
Organic vapor
Actual concentration
(ppm)
Catalytic combustion
Meta-xylene
Response factors
Unit #1 Unit #2
200
1500
3000
4500
7000
3.5
9.4
12.8
15.0
37.9
1.7 .
2.0
1.6
1,5
1,7
shows that extreme reading differences could occur between
two supposedly identical units. A reason may exist for this
difference; for example, in this catalytic combustion unit, the
catalyst coated wire was damaged from exposure to high
organic vapor concentrations.
Field Monitoring Problems
This segment of the chapter is related to actual field use
of the instrument. In conducting field monitoring, several
common problems need to be considered in order to identify
leak:; reliably. Such problems in field monitoring procedures,
including limited capture, extreme volatile organic compound
(VOC) quantities, and weather conditions, are discussed be-
low.
Limited Capture
Before discussing problems in field monitoring proce-
dure:? as they relate to capture, the differences between gas
flow under positive pressure versus gas flow under negative
pressure must be understood. The portable VOC analyzer
works under negative pressure. Because of its negative pres-
sure characteristics, the sample gas capture and distance of
effectiveness is nearly zero, several diameters away from the
probe entrance. Leaks leaving the leaking equipment are
under positive pressure. The characteristic effects of the posi-
tive pressure result in limited dispersion and gradual decelera-
tion causing the leak to persist out as a narrow jet.
Because of the effects of negative and positive pressure
mentioned above, limited capture is related to instrument
sample gas flow rates and probe orientation to the VOC
"plume." Limited capture can result in nondetection of some
leaks. Instruments with low gas sampling rates are especially
sensitive to the capture problems. For this reason, leaks are
easy to miss unless the following steps are taken:
• Locate the probe fairly close to the leak itself.
• Orient the probe so that the positive pressure characteris-
tics of the leak benefit the capture (injects material into
the probe and does not act as a cross draft which would
make capture poor).
Extreme VOC Quantity
Extreme VOC quantity problems can result because the
instrument is too good at capture, thus taking in a high
concentration of VOC material. In the case of a flame ioniza-
tion detector (FID), the unit may not operate properly because
the detector flame may go out due to lack of adequate oxygen
to support combustion, or condensation may occur of non-
volatile components in sample line, flame arrestor leading to
the mixer burner, or exhaust flame arrestor. Photoionization
detectors, however, present a somewhat different problem.
Flame-out is not the problem under consideration, but rather
deposits of some of the nonvolatile compounds on the lamp
surface. This can result in loss of instrument sensitivity and
inability to read anything even though the probe may be
sitting in a high concentration leak.
For these reasons, emphasis must be placed not only on
gettin g close to the leak and proper orientation, but also on not
staying near the leak for very long. As soon as a leak is
indicated, the instrument should be withdrawn. The instru-
101
-------
ment should not be at a high concentration for a very long
lime. A mistake of this nature will shut the instrument down
for a day and will necessitate a thorough cleaning, which
could take hours. For best results, the instrument probe should
be moved as slowly as possible around the potential leaking
area due to the limited capture problems that can make leaks
disappear. However, because of the potential for extreme
VOC quantities, the probe should be withdrawn immediately
if a high concentration is found.
Adverse Weather
In addition to procedures that minimize problems be-
cause of limited capture and extreme VOC intake, instrument
problems that can be created by adverse weather conditions
must be considered. Portable VOC analyzers should not be
used in the rain. Droplets inadvertently drawn into the probe
can cause minor damage to the various types of sensors (e.g.,
flame ionization units—water can partially plug flame arres-
ters; photoionization detectors—droplets can coat the optical
surfaces).
Even after the rain is over, some care is necessary in
checking for leaks. Taking in water from small pools can
damage the instrument. Exercise caution when downwind of
small steam vents or other sources of moisture. A sudden
change in wind direction can cause intake of fine droplets and
damage.
Safety
Follow plant safety procedures. Avoid hot surfaces, rotat-
ing equipment, and valves that may be reached only by
standing on a fixed caged ladder. Do not use portable ladders
and avoid valves in high locations unless a safe and conve-
nient access exists. In addition, only those portable analyzers
and equipment that have been rated as intrinsically safe should
be taken into these areas.
In conclusion, several problems may be encountered in
field monitoring procedures that cause or prevent the adequate
determination of leaks including limited capture, extreme
VOC quantities, and weather conditions. To minimize these
problems, locate the probe close to equipment because of
capture limitations, vary probe orientation to find leaks, with-
draw the probe if the gauge suddenly spikes above the action
level, avoid any droplet intake into equipment due to rain or
spray, and work safely during the fugitive VOC screening.
Health and safety considerations during field monitoring
are shown in Table 12-10. These precautions should be ob-
served in addition to following general plant safety guide-
lines.
Comparison of Available Instruments
With respect to Method 21 requirements, the major com-
parison point to consider is whether the response factor is
acceptable for a particular instrument applied to detecting a
particular compound. Perhaps a choice exists of two or three
different types of devices for a particular monitoring situation.
After determining that response factors are within acceptable
ranges for more than one type of instrument, go on to the next
set of criteria.
Table 12-10. Health and Safety Considerations
Inhalation hazards
Keep portable organic analyzer on at all times to indicate
localized areas where pollutants havo accumulated
Use relatively long probe so user does not have to be exposed
to leak plume
Electrical and explosion hazards
Use only instruments rated intrinsically safe for Class 1, Division
1, and Class 2, Division 1 conditions
Use only instrument recorders which satisfy the above require-
ments
Do not touch rotating shafts with metallic probes or other parts
Do not use cigarette lighters to check instrument response
Burn hazards
Avoid hot surfaces adjacent to equipment being screened
Walking and climbing hazards
Avoid exposed rotating equipment
Avoid equipment more than 2 meters above secure platforms or
surfaces
Climb ladders properly
Ease of Use
The ease of use points are response time, configuration,
calibration, and reliability. The mer.hod allows you to use
instruments with response times up to 30 seconds, but if you
have a large facility with many sources, you should look for
an instrument that has shorter response times. Otherwise,
much time can be spent around the pumps and valves that are
not leaking because the method requires continuing to search
for a leak up to twice the length of the response time for the
instrument.
With respect to configuration, placement of the meter in
relation to the sampling probe is important. This point is
discussed more in a later section.
Instrument Costs
Most people tend to focus on the purchase price of the
instrument initially, but factors also exist that affect the cost of
the instrument over its operating life. For instance, ultraviolet
light replacement in the case of the photoionization analyzer
is an important operating cost. In the flame-ionization detec-
tor case, the hydrogen supply must be replaced. A hydrogen
tank must be available to recharge the instrument tank (Table
12-11). :
Comparison Summary
Available instrument types are compared in Table 12-11.
Across the top of the table are the four types of analyzers that
can be used for leak detection work. Down the side are the
considerations to be made if a choice among these types is
possible. For response times, both the photoionization and
flame-ionization analyzers are indicated to be fast responding,
catalytic combustion medium, and infrared slow. These all are
102
-------
Table 12-11. Comparison of Available Instruments*
Analyzer type
Criteria
Flame
ionization
Photo-
ionization
Catalytic
combustion
Infra-
red
Ease of Use
Response time
Weight (portability)
Contamination susceptibility
Configuration
Maximum concentration capability
Costs
Capital
Operating
Fast
Heavy
Low
Excellent
Excellent
Moderate
Moderate
Fast
Light
Moderate
Adequate
Adequate
Moderate
Moderate
Medium
Light
Low
Adequate
Excellent
Low .
Moderate
Slow
Heavy
Moderate
Adequate
Excellent
Moderate
Moderate
Other Concerns
Ruggedness
Maximum hold feature
Calibration
Capture capability
Good
No
Good
Excellent
Good
Yes
Good
Adequate
Good
No
Good
Moderate
Good
No
Good
Moderate
"A variety of models are available; the comparisons are subjective and based on experience with a limited number of models.
within the 30-second response time requirement of the method,
but for the flame ionization and photoionization types fast
may mean 5 seconds, and for infrared slow may mean 25
seconds. Flame-ionization analyzers are typically equipped
with lead acid batteries and a hydrogen tank that makes them
relatively heavy. The catalytic and photoionization instru-
ments are relatively light.
The photoionization analyzer and infrared analyzers are
moderately susceptible to contamination. The window is a
potential problem in both that may require more frequent
attention, although it may not be a major difficulty in keeping
the instruments in operating condition.
Configuration refers to the issue of where the sampling
probe is in relation to the meter that must be read while doing
the survey. Designs that locate the meter directly behind or at
the end of the probe are easier to use. The method requires the
probe tip to be placed close to the equipment that is being
surveyed. Position the meter and probe so that both can be
seen at the same time.
With respect to maximum concentration capability, only
the photoionization analyzer is rated differently. Because
photoionization analyzers are not capable of directly reading
concentrations that exceed 1,000 to 2,000 ppm, a dilution
probe must be used with this instrument if looking for leaks at
10,000 ppm
The cost information presented here was obtained from
telephone quotes. The flame-ionization type analyzer gener-
ally is available for $4,000 to $7,000. The photoionization
analyzers are available for $4,000 to $6,000. These instru-
ments come equipped with other convenient features that may
not be essential to the leak detection work but may cause the
cost to vary. Cost of the catalytic combustion analyzers is in
the $2,000 to $4,000 range. They are shown as being a
relatively low-cost device, but reasons may exist for their not
being as good for leak detection as the other types.
A moderate cost for infrared is indicated in Table 12-11.
However, the one quote received for an infrared device was
$16,000, which would not be moderate. Apparently some are
available for less than that.
No difference is shown in operating costs. Consider the
portions of the instrument that may fail or need replacement,
such as the lamps, the hydrogen supply, and batteries. Instru-
ment manufacturers are probably the best source for informa-
tion about these operating costs for their particular instrument.
All instruments are rated similarly for ruggedness or how
they stand up to abuse in the field.
The maximum hold feature may be important for instru-
ments that have the sampling probe and meter in two different
locations. An analyzer that locks in the maximum concentra-
tion that the meter achieves while in the middle of a survey
can be helpful. One photoionization analyzer has this feature.
All instruments are rated similarly for calibration. Cap-
ture capability is really a reference to the flow rates of the
instruments. The flame-ionization analyzer is rated as excel-
lent because it is at the high end of that flow rate range
allowed by the method. Photoionization is indicated as ad-
equate because it is at the low end of the acceptable flow
range. Low flow rates do not capture the leaking vapors as
well.
103
-------
Questions and Answers
Question—What factors should be considered in choosing a
lamp for a photoionization detector?
Answer*—Photoionization lamps thatoperateatdifferentvoltage
levels areavailableforpurchase. The first consideration in
choosing the lamp is the ionization potential of the
compounds for which measurements will be needed. The
lamp selected should be capable of ionizing any compound
likely to be present, i.e., the compound with the highest
ionization potential. Published tables are available that list
compound ionization potentials. The information may also
be obtained from the instrument or lamp suppliers. Lamp
voltages in the 9- to 11-electron volt range are common.
The higher voltage lamps are more sensitive to a broad
range of organic compounds, but have shorter service lives
than the lower voltage lamps. Therefore, more frequent
replacementandhigheroperatingcostsfortheinstruments
can be anticipated with the higher voltage lamps.
Question—How can photoionization analyzers be used for leak
monitoring if they cannot read concentrations higher than
1,000 to 2,000 ppm?
Answer—Photoionization analyzers can be used to demonstrate
that equipment designated for no detectable emissions has
no detectableemissions,i.e.,no measured concentration of
emissions 500 ppm or greater than background level. If
photoionization analyzers are to be used to monitor
equipment for leaks that are defined by concentrations of
10,000 ppm or greater, a dilution probe must be used with
the instrument The dilution probe mixes a known volume
of air with the sampled gas stream to ensure that a sampled
gas stream concentration of 10,000 ppm will be diluted to
a concentration within the capability of the instrument to
measure when the combined stream enters the detection
chamber. The measured concentration reported by the
instrumentmetermustbemultipliedby thedilutionratio to
give the concentration of the sampled gas stream. For
example, if thedilution ratio for thedilution probe is 6parts
of air to 1 partof sampled gas, ameter reading of 1,000 ppm
means that the concentration of organics in the sampled gas
stream is 6,000 ppm.
Question—Wastes may contain a large number of organic
compounds; how do you determine whether a particular
instrument will adequately respond to the combination of
vapors that may leak from equipment?
Answer—According to Method 21, the instrument response
factor for each compound that is to be measured must be
less than 10. Withamixtureof afew compounds, checking
the published response factors and verifying their
compliance is not difficult. Some limited study suggests
that the response factor for a mixture is simply the weighted
average response factor of the multiple components when
the compounds are similar, such as the two forms of
tetrachloroethane (1,1,2,2 and 1,1,1,2). For other mixtures
involving compounds with substantially differentmolecular
structures and volatility characteristics, this may not be the
case. Also, the relative concentrations of vapors present
above a mixture of organics could be substantially different
than the relative concentrations of those compounds in
leaking liquids, so the correct weighted average to use may
not be obvious. A possible solution to the problem would
be to prepare a mixture of known concentrations to sim ulate
the waste, and then experimentally determine the response
factor for vapors of the mixture. If the response factor for
the mixture is less than 10, the ins trument may be used. For
a mixture composed of a very large number of compounds,
this may not be practical. Perhaps a mixture that represents
90 percent of the compounds present in the waste would be
a suitable basis for response factor determination. The
acceptability of the latter approach would need to be
discussed with EPA officials before adopting it.
Question—Can analyzers that use combustion to detect the
presence of organic vapors be safely used in potentially
explosive atmospheres?
Answer—Both flame ionization and catalytic combustion type
analyzers have flames present in their detection chambers
when organic vapors are present. Certain models of these
devices are rated intrinsically safe, and can be used in
explosive atmospheres safely. The intrinsically safe models
are constructed with flame arresters to prevent the
propagation of flame into the explosive atmosphere. In
Method 21, the instruments used are required to be
intrinsically safe as defined by the applicable standards
such as the National Electric Code by the National Fire
Prevention Association. They must at a minimum be safe
for Class 1, Division 1 conditions, and Class 2, Division 1
conditions as defined by the above code.
Question—When an instrumentresponse factor foraparticular
compound is 9.5, which means the actual concentration
being measured is 9.5 times higher than indicated by the
meter, can severe leaks be missed?
Answer—Leaks, when they occur, tend to generate very high
concentrations. The concentrations are generally much
higher than the 10,000-ppm leak definition, typically in the
100,000- to 500,000-ppm range. Given this behavior,
instrument response factors up to 10 would still yield an
indication that a leak is present.
104
-------
Appendix A
Federal Register Excerpt
Revised Method 21
105
-------
Federal Register, Vb/JJ, No. 121, Friday, June 22, 1990,
Rules and Regulations, Pages 25602-25604
ENVIRONMENTAL PROTECTION AGENCY
[AD-FRL-3727-3]
40 CFR Part 60
Standards of Performance for New Stationary
Sources; Test Methods
AGENCY:
Environmental Protection Agency (EPA).
ACTION: Final rule.
Summary
Method 21 applies to the determination of volatile organic
compounds (VOC) leaks from process equipment such as
valves, flanges and connections, pumps and compressors, and
pressure relief devices. Since Method 21 was promulgated in
1983, several deficiencies in the method that could lead to
inconsistencies in the determination of VOC leaks from such
devices have come to the attention of EPA in the form of
questions as to the proper application of the method. On May
30, 1989, EPA proposed appropriate additions and revisions
to Method 21 to alleviate any deficiencies (54 FR 22920).
This action promulgates those additions and revisions.
Dates
Effective Date. June 22,1990. Judicial Review. Under section
307(b)(l) of the Clean Air Act, judicial review of the actions
taken by this notice is available only by the filing of a petition
for review in the U.S. Court of Appeals for the District of
Columbia Circuit within 60 days of today's publication of this
notice. Under section 307(b)(2) of the Clean Air Act, the
requirements that are the subject of today's notice may not be
challenged later in civil or criminal proceedings brought by
EPA to enforce these requirements.
Addresses
Docket. A docket, number A-88-29, containing information
considered by EPA in development of the promulgated
rulcmaking is available for public inspection between 8 a.m.
and 4 p.m., Monday through Friday, at EPA's Air Docket
Section (LE-131), room M-1500, First Floor, Waterside Mall,
401 M Street SW., Washington, DC 20460. A reasonable fee
may be charged for copying.
For Further information Contact
William Grimley or Roger T. Shigehara, Emission Measure-
ment Branch (MD-19), Technical Support Division, U.S.
Environmental Protection Agency, Research Triangle Park,
North Carolina 27711, telephone (919) 541-2237.
Supplementary Information
/. The Rulemaking
Section 2.4 is being revised to remove a description of the
leak determination procedure, which is already given, and
more properly belongs in section 4.3.2. The example of an
acceptable increase in surface concentration versus local con-
centration is incorrect, and is being removed, as all existing
regulatory subparts state that any reading less than 500 ppm
constitutes "no detectable emissions:." The definition is now
expressed in terms of the instrument readability specification.
Section 3.1.1(b) is being revised because it is important to call
attention to the possibility that the leak definition concentra-
tion may be beyond the linear response range of some instru-
ments for some VOC. This potential problem is not identified
by the existing calibration procedure, which specifies a single
upscale VOC calibration gas. An argument could be made that
a multipoint calibration should, therefore, be required. How-
ever, adding that requirement would increase the method's
performance burden and cost.
Section 3.1.1(c) is being revised in consideration of existing
regulatory subparts, where the intention is for the readability
to be to the nearest 500 ppm. Since the leak definition in
existing subparts is 10,000 ppm, the nearest 500 ppm repre-
sents ±2.5 percent, not ±5 percent.
Section 3.1.1(d) is being revised to prevent any flow interrup-
tion from occurring, such as could occur if a manually oper-
ated device was used for a pump. The minimum flow rate
specification of 0.50 liter per minute is reduced to 0.10 liter
per minute to prevent the exclusion of some instruments that
do meet the response time specification and could be accept-
able if this change was made, the flow rate specification has
been qualified as to where, and under what conditions, it
applies in order to prevent misunderstandings that it might
apply at the instrument detector, or with no flow restriction in
the probe. The upper flow limit specification of 3.0 liters per
minute is retained because some upper limit on flow rate is
required to prevent dilution of any leaking VOC to a concen-
tration below the definition of a leak.
Section 3/l/l(e) is being revised in consideration of com-
ments that have been made to EPA that existing wording is
not clear and should be more specific. In addition, it has been
reported that inexperienced sampling personnel have been
observed to use a portable flame ionization analyzer with the
exhaust flame arrester not replaced after removal for cleaning.
Section 3.1.l(f) is being added to emphasize that the instru-
ment is meant to sample a discrete area. Some probes have
been observed to have a relatively large inlet area. The addi-
tion is necessary so as to provide as much consistency in the
identification of leaks as is reasonably possible. All measure-
ments made by EPA in support of its VOC-leaks regulatory
development activities have been made with probes not over
1/4 in. in outside diameter.
Section 3.1.2(a) is being revised to include a procedure that is
needed for those instances where an instrument is not avail-
able that meets the response criteria, when calibrated with the
specified (in regulation) VOC calibration gas. The new proce-
dure should meet the spirit of existing VOC-leak regulations.
106
-------
Finally, Section 3.1.2(b) is being revised by replacing the
word "configuration" with all of the items of sampling equip-
ment that might be between the probe tip and the detector
during testing.
This rulemaking does not impose emission measurement re-
quirements beyond those specified in the current regulations,
nor does it change any emission standard. Rather, the
rulemaking would simply add methods for the achievement of
emission testing requirements that would apply irrespective of
this rulemaking.
//. Public Participation
The proposed amendment to 40 CFR part 60 that contained
proposed revisions and additions to Method 21 was published
in the Federal Register on May 30, 1989 (54 FR 22920).
Public comments were solicited at the time of proposal. To
provide interested persons the opportunity for oral presenta-
tion of data, views, or arguments concerning the proposed
action, a public hearing was scheduled for July 14, 1989
beginning at 10 a.m., but was not held because no one
requested to speak. The public comment period was from May
30, 1989 to August 14, 1989. Two comment letters were
received that contained comments concerning the proposed
methods. The comments were supportive of the proposed
additions and revisions, with one exception. That comment
has been carefully considered, but no changes were made to
the proposed rulemaking.
///. Comments and Changes to the Proposed
Standards
Two comment letters were received from synthetic organic
chemical manufacturers on the proposed methods. All but one
of the comments therein were statements to the effect that the
commenter agreed with the proposed additions and revisions.
The one exception stated that the commenter did not agree
that an electrically driven pump should be required in section
The EPA believes it is necessary to specify that an electrically
driven pump be used in order to eliminate any potential for Dated: June 7, 1990.
imprecise results due to variations or interruptions in sample
flow arising from the use of a hand operated squeeze pump. It
may be possible for a given person to use a hand operated
pump satisfactorily, but EPA believes that technique is too
prone to operator fatigue over the course of an extensive leak
survey to permit its use in a reference method, and is, there-
fore, not making any change in the requirement for an electri-
cally driven pump.
interagency review materials, will serve as the record in case
of judicial review [Clean Air Act, section 307(d)(7)(A)J.
Under Executive Order 12291, EPA is required to judge
whether a regulation is a "major rule" and, therefore, subject
to the requirements of a regulatory impact analysis. The
Agency has determined that this regulation would result in
none of the adverse economic effects set forth in section 1 of
the Order as grounds for finding a regulation to be a "major
rule." The rulemaking does not impose emission measure-
ment requirements beyond those specified in the current regu-
lations, but instead, provides methods for performing emis-
sion measurement requirements that would apply irrespective
of this rulemaking. The Agency has, therefore, concluded that
this regulation is not a "major rule" under Executive Order
12291.
The Regulatory Flexibility Act (RFA) of 1980 requires the
identification of potentially adverse impacts of Federal regu-
lations upon small business entities. The Act specifically
requires the completion of an RFA in those instances where
small business impacts are possible. Because these standards
impose no adverse economic impacts, an RFA has not been
conducted.
Pursuant to the provisions of 5 U.S.C. 605(b), I hereby certify
that the promulgated rule will not have any economic impact
on small entities, because the rule does not add either to the
existing requirement for flow rate measurements, or increase
their associated performance cost.
This regulation was submitted to the Office of Management
and Budget (OMB) for review as required by Executive Order
12291. Any written comments from OMB and any written
EPA responses are in the docket
List of Subjects in 40 CFR Part 60
Air pollution control, Intergovernmental relations, Synthetic
Organic Chemicals Manufacturing Industry, Reporting and
record keeping requirements.
William K. Reilly,
Administrator.
Method 21, appendix A of 40 CFR part 60 is amended as
follows:
IV. Administrative
1. The Authority for 40 CFR part 60 continues to read as
follows:
Authority: Sections 101, 111, 114,116, and 301 of the Clean
Air Act, as amended (42 U.S.C. 7401, 7411, 7414, 7416,
7601).
The docket is an organized and complete file of .all the
information considered by EPA in the development of this
rulemaking. The docket is a dynamic file, since material is
added throughout the rulemaking development. The docket- Appendix A [Amended]
ing system is intended to allow members of the public and 2. By revising section 2.4 to read as follows
industries involved to identify readily and locate documents
so that they can effectively participate in the rulemaking
process. Along with the statement of basis and purpose of the
proposed and promulgated standards, and EPA responses to
significant comments, the contents of the docket, except for
2.4 No Detectable Emission. Any VOC concentration at a
potential leak source (adjusted for local VOC ambient con-
centration) that is less than a value corresponding to the
instrument readability specification of section 3.1.l(c) indi-
cates that a leak is not present.
107
-------
3. By revising section 3.1.1 (b), (c), (d), and (e) and adding (0
to read as follows:
3.1.1 Specifications.
(b) Both the linear response range and the measurable range of
the instrument for each of the VOC to be measured, and for
the VOC calibration gas that is used for calibration, shall
encompass the leak definition concentration specified in the
regulation. A dilution probe assembly may be used to bring
the VOC concentration within both ranges; however, the
specifications for instrument response time and sample probe
diameter shall still be met.
(c) The scale of the instrument meter shall be readable to ±2.5
percent of the specified leak definition concentration when
performing a no detectable emission survey.
(d) The instrument shall be equipped with an electrically
driven pump to insure that a sample is provided to the detector
at a constant flow rate. The nominal sample flow rate, as
measured at the sample probe tip, shall be 0.10 to 3.0 liters per
minute when the probe is fitted with a glass wool plug or filter
that may be used to prevent plugging of the instrument.
(e) The instrument shall be intrinsically safe as defined by the
applicable U.S.A. standards (e.g., National Electric Code by
the National Fire Prevention Association) for operation in any
explosive atmospheres that may be encountered in its use. The
instrument shall, at a minimum, be iintrinsically safe for Class
1, Division 1 conditions, and Class 2, Division 1 conditions,
as defined by the example Code. Tlhe instrument shall not be
operated with any safety device, such as an exhaust flame
arrester, removed.
(0 The instrument shall be equipped with a probe or probe
extension for sampling not to exceed 1/4 in. in outside diam-
eter, with a single end opening for admission of sample.
4. By revising section 3.1.2 (a) and (b) to read as follows:
3.1.2 Performance Criteria.
(a) The instrument response factors for each of the VOC to be
measured shall be less than 10. When no instrument is avail-
able that meets this specification when calibrated with the
reference VOC specified in the applicable regulation, the
available instrument may be calibrated with one of the VOC
to be measured, or any other VOC, so long as the instrument
then has a response factor of less than 10 for each of the VOC
to be measured.
(b) The instrument response time shall be equal to or less than
30 seconds. The instrument pump, dilution probe (if any),
sample probe, and probe filter, chat will be used during
testing, shall all be in place during l;he response time determi-
nation.
[FR Doc. 90-13845 Filed 6-21-90; 8:45 am]
108
-------
Appendix B
Published Response Factors
(From EPA 340/1-88-015)
Table B-1.
Compound
Response Factors for TECO Model 580 Photoion-
ization Type Organic Vapor Analyzers 10.0 ev
Lamp
lonization
Potential Response
(ev)
Factor
Acetone
Acetophenone
Acrolein
Ammonia
Aniline
Benzene
1 ,3-Butadiene
Carbon disulfide
Chlorobenzene
Cyclohexane
1 ,2-Dichloroethane
Diethylamine
Dimethyl sulfide
Ethyl benzene
Ethylene oxide
Ethyl ether
Hexane
Hydrogene sulfide
Isopropanol
Methyl ethyl ketone
Methyl isocyanate
Methyl mercaptan
Methyl methacrylate
Nitric oxide
Ortho chloro toluene
Ortho xylene
Pyridine
Styrene
Sec butyl bromide
Tetrachloroethene
Tetrachloroethylene
Tetrahydrofuran
Toluene
Trichloroethylene
' 9.58
N.D.*
N.D.
10.15
7.70
9.25
9.07
10.0
9.07
9.98
N.D.
N.D.
8.69
8.75
10.57
9.53
10.18
10.45
10.16
9.53
10.57
9.4
N.D.
9.25
8.83
8.56
9.32
N.D.
9.98
9.32
N.D.
9.54
8.82
N.D.
1.7
•-. 4.2 •:
25.0
24.5
'•'• 0.6
0^7
•1,0
2.3
0.5
2.1
50.0
2.0
1.3
17
33.8
1.5
11.3
7.3
19.8
1.6
12.5
1.3
4.2
44.9
0.5
0.8
0.6
3.3
1.7
1.6
1.9
3.7
0.5
1.3
* N.D. = not detected
109
-------
Tabla B-2. Response Factors for the Hun Systems, Inc., Model ISPI-101 Photoionization Analyzer
Compound
Acelal
Carbon disulfide
Carbon ttrachloride
Chloroform
Diketone
Porchloromothyl mercaptan
Tolueno
Telrachtoro9thane,1 . 1 ,2,2-
Trichloroethan9,1,1-
Trichlorotrifluoroethane,1,1,2-
Actual
Concentration
1000
5000
10000
1000
10000
500
1000
10000
1000
5000
10000
1000
5000
10000
5000
1000
1000
5000
10000
1000
5000
10000
5000
10000
Instrument
Concentration
925
7200
13200
1990
12900
784
1070
6070
756
2550
5250
148
318
460
103
1180
736
1170
1880
1020
6170
9430
155
430
Response
Factor
1.1
0.69
0.76
0.50
0.78
0.64
0.94
1.6
1.3
2.0
1.9
6.8
16.0
22.0
48.0
0.85
1.4
4.3
5.3
0.98
0.81
1.1
32.0
23.6
110
-------
Table B-3. Response Factors for Foxboro OVA-108 and Bacharach TLV Sniffer at 10,000 ppmv Response
Response Factor
Compound OVA-108
Acetic acid 1 .64
Acetic anhydride 1 .39
Acetone 0.80
Acetonitrile 0.95
Acetyl chloride 2.04
Acetylene 0.39
Acrylic acid 4.59
Acrylonitrile 0.97
Allene 0.64
Allyl alcohol 0.96
Amylene 0.44
Anisole 0.92
Benzene 0.29
Bromobenzene 0.40
Butadiene, 1,3- 0.57
Butane, n 1 .44 I
Butanol, sec- 0.76
Butanol, tert 0.53
Butene,1- 0.56
Butyl acetate 0.66
Butyl acrylate, n- 0.70
Butyl ether, n 2.60
Butyl ether, sec 0.35
Butylamine, n 0.69
Butylamine, sec 0.70
Butylamine, tert- 0.63
Butyrandehyde, n- 1.29
Butyronitrile 0.52
Carbon disulfide B
Chloroacetaldehyde 9.10
Chlorobenzene 0.38
Chloroethane 5.38 I
Chloroform 9.28
Chloropropene,1- 0.67
Chloropropene.3- 0.80
Chlorotoluene, m- 0.48
Chlorotoluene.o- 0.48
Chlorotoluene, p- 0.56
Crotonaldehyde 1 .25
Cumene 1.87
Cyclohexane 0.47
Cyclohexanone 1 .50
Cyclohexene 0.49
Cyclohexylamine 0.57
Diacetyl 1 .54
Dichloro-l-propene,2,3- 0.75
Dichloroethane,1,1- 0.78
Dichloroethane,1,2- 0.95
Dichloroethylene,cis!,2- 1 .27
Dichloroethylene,transl,2- 1.11
Dichloromethane 2.81
Dichloropropane.1,2- 1.03
Diisobutylene 0.35
Dimethoxy ethane, 1,2- 1.22
Dimethylformamide.n.n- 4.19
Dimethylhydrazine 1,1- 1.03
Dioxane 1 .48
Epichlorohydrin 1 .69
Ethane 0.65
Ethanol 1 .78
Etboxy ethanol, 2- 1.55
Ethyl acetate 0.86
Ethyl acrylate 0.77
Ethyl chloroacetate . 1 .99
Ethyl ether 0.97
I Inverse Estimation Method
D Possible Outliers in Data
N Narrow Range of Data
Response Factor
TLV Sniffer
15.60
5.88
1.22
1.18
2.72
B
B
3.49 I
15.00
X
1.03
3.91
1.07
1.19
10.90
4.11
1.25
2.17
5.84
1.38
2.57 I
3.58 I
1.15
2.02
1.56
1.95
2.30
1.47 I
3.92
5.07
0.88
3.90 P
B
0.87
1.24
0.91
1.06
1.17 1
B
B
0.70
7.04
2.17
1.38
3.28
1.75
1.86
2.15
1.63
1.66
3.85
1.54
--• 1 .41
1.52
5.29
2.70
1.31
2.03
0.69 I
X
1.82
1.43
X
1.59
1.14
Response Factor
Compound OVA-108
Ethylbenzene
Ethylene
Ethylene oxide
Ethylenediamine
Formic acid
Glycidol
Heptane
Hexane, n-
Hexene.1-
Hydroxyacetone
Isobutane
Isobutylene
Isoprene
Isopropanol
Isopropyl acetate
Isopropyl chloride
Isovaleraldehyde
Mesityl oxide
Methacrolein
Methanol
Methoxy-ethanol,2-
Methyl acetate
Methyl acetylene
Methyl chloride
Methyl ethyl ketone
Methyl formate
Metayl methacrylate
Methyl-2-pentanol,4-
Methyl-2-pentone,4-
Methyl-3-butyn-2-ol,2
Methylcyclohexane
Methylcyclohexene
Methylstyrene.a-
Nitroethane
Nitromethane
Nitropropane
Nonane-n
Octane
Pentane
Picoline,2- ,
Propane
Propionaldehyde
Propionic acid
Propyl alcohol
Propylbenzene.n-
Propylene
Propylene oxide
Pyridine
Styrene
Tetrachloroethane,1 ,1,1,2
Tetrachloroethane.1,1,2,2
Tetrachloroethylene
Toluene
Trichloroethane, 1,1,1 -
Trichloroethane, 1,1,2-
Trichloroethylene
Trichloropropane,1 ,2,3-
Triethylamine
Vinyl chloride
Vinylidene chloride
Xylene, p-
Xylene, m-
Xylene, o-
X No Data Available
0.73
0.71
2.46
1.73
14.20
6.88
0.41 I
0.41
0.49
6.90
0.41
3.13
0.59
0.91
0.71
0.68
0.64
1.09
1.20
4.39 P
2.25
1.74
0.61
1.44
0.64
3.11
0.99
1.66
0.56
0.59
0.48
0.44
13.90
1.40
3.52
1.05
1.54
1.03
0.52
0.43
0.55 I
1.14
1.30
0.93
0.51
0.77
0.83
0.47
4.22
4.83 D
7.89
2.97
0.39
0.80
1.25
0.95
0.96
0.51
0.84
1.12
2.12
6.40
0.43
Response Factor
TLV Sniffer
4.74 D
1.56
2.40
3.26
B
5.55
0.73
0.69
4.69 D
15.20
0.55
B
X
1.39
1.31.
0.98
2.19 D
3.14
3.49 D
2.01
3.13
1.85
6.79
1.84
1.12
1 .94
2.42
2.00
1.63
X
0.84
2.79
B
3.45
7.60
2.02
11.10
2.11
0.83
1.18
0.60 P
1.71
5.08 D
1.74
B
1.74 I
1.15
1 1fi
1 . 1 Q
•g
6.91
25.40
B
2.68 D
2.40
3.69
3.93
1.99
1.48
1.06
2.41
7.87
5.87 D
1.40
B 1 0,000 ppvm Response Unachievable
P Suspect Points Eliminated
111
-------
Response Factor Test Results
The calculated response factors are presented in Table
B-4. This table is organized by compound name, with the
response factors presented for the test instruments. Qualifiers
for the data are noted.
Those compounds for which a large response factors was
determined (e.g., five and greater) indicate a problem, and
these values should not be used. The response factor is a
multiplier, and errors in field measurements caused by changes
in calibration response, battery condition, parallax errors in
reading the panel meters, etc., would be unduly compounded.
Response factors were determined specifically for 500
ppm and should be used as a leak/no leak indicator. The
response factors do not remain constant as the concentrations
change from 500 ppm. Use of these response factors to
determine concentrations at 2500 ppm, for example, would be
inaccurate, and the operator would be best advised to redeter-
mine a response factor specifically for the new conditions or
use a published value at the correct level.
Operators of portable leak detection devices should be
thoroughly familiar with their instrumentation. Even under the
best of circumstances, no two analyzers will perform exactly
the same, and the knowledge of how changes in instrument
parameters affect accuracy become paramount. Other external
quality controls, such as a checklist periodically noting battery
condition, fuel pressure, post-survey calibration checks, etc.,
will bolster the validity of the data. An audit program testing
both the operator and the analyzer should be a requirement
whenever a situation warranting an exacting determination of
a fugitive emission is encountered.
Source: Afotfwd2» Evaluation for the HON (90-ME-07). September 30,1990, Office of Air Quality Planning and'Standards, U.S. E-nvironmental Protection Agency,
Rosearch Triangle Park, NC 27711.
112
-------
Table B-4.
Response Factors Summation Table
Manufacturer
Analyzer
Serial Number
Foxboro
OVA- 108
20868
Foxboro
OVA- 128
41092
Foxboro
OVA-128
41102
Health
DP 111
1001
HNU
HW-101
See Text
Foxboro
Miran 1B2
322214
Compound/Calculated Response Factor
Vinyl chloride
Benzene
Acetonitrile*
Hexane
Isobctane
Methyl ethyl ketone
Methyl isobutyl ketone
Carbon tetrachloride*
Chloroform
Benzyl chloride
1 ,4-Dioxane
Toluene
Carbon Disulfide*
Methanol*
1,1, 2-Trichloroethane
1,1,1 -Trichloroethane
Ethylene dichloride
Tetrachloroethlylene
Ethylbenzene
Methyl tert-butyl ketone
ortho-Xylene
para-Xylene
meta-Xylene
Acetophenone**
Styrene oxide**
Nitrobenzene***
Chloroacetyl chloride
1,1, 2, 2-Tetrach loroethane
Ethylene glycol***
2-Methoxyethanol***
Isophorone***
1 ,2- Epoxybutane
Trichloroethylene
Chlorobenzene
Acetaldehyde*
1 ,2 - Propyleneimine
Propylene oxide
Vinylidene chloride
1 ,3 - Dichloropropene
Acrolein*
Allyl chloride
Cumene**
Vinyl acetate
Methyl methacrylate
Ethyl acrylate
Styrene
Aniline***
Epichlorohydrin
Propionaldehyde*
Hexachlorobutadiene***
Methylene chloride
Propylene dichloride
2-Nitropropane
Triethylamine
lodomethane*
Bromoform*
2.03
0.56
1.20
1.42
1.05
1.78
1.65
12.07
2.06 v
, 1.43
3.74
0.87
33.87 .
13.24
1.19
1.09
1.37
1.77
0.77
1.23
0.95
0.89
0.89
2.71
2.61
16.41
1.86
1.64
24.81
9.61
28.80
2.67
2.26
0.62
8.41
1.75
2.02
2.73
2.03
6.25
2.77
2.05
3.63
2.02
2.49
1.10
14.44
2.30
4.01
16.28
1.67
1.49
1.86
0.47
8.06
5.90
2.11
0.54
1.24
1.49
1.05
1.84
1.69
15.99
2.38
1.42
4.27
0.87
53.06
17.34
1.27
1.16
1.59
2.09
0.76
1.25
0.95
0.88
,0.89
2.62
2.49
16.52
1.93
1.69
39.39
9.87
40.71
2.54
2.60
0.60
9.96
1.52
2.14
2.97
2.08
6.69
2.73
1.82
3.36
2.16
2.64
1.08
20.45
2.41
4.27
22.99
1.72
1.48
1.91
0.49
8.76
6.71
2.11
0.50
1.27
1.33
0.89.
1.59
1.40
13.72
1.91
1.21
3.60
0.76
N/R
N/R
1.11
1.03
1.41
1.72
0.66
1.03
0.80
0.74
0.75
2.43
2.06
N/R
1.66
1.66
N/R
N/R
N/R
•2.16
2.14
0.54
7.95
1.53
1.78
2.61
1.93
5.64
2.51
1.55
2.80
1.81
2.18
0.93
22.68
2.07
3.95
18.06
1.41
1.26
1.60
0.48
7.35
5.68
1.76
0.38
1.27
0.93
0.56
1.19
0.98
11.11
1.38
0.95
3.21
0.57
57.06
21.73
0.79
0.70
1.19
1.20
0.51
0.72
0.6
0.54
0.54
2.92
2.61
26.01
1.28
1.14
33.13
7.91
29.69
1.89
1.25
0.38
5.36
1.33
1.26
1.79
1.23
•3.71
1.56
0.79
1.48
0.92
1.16
0.57
14.71
1.27
2.53
14.56
0.84
0.84
1.06
0.35
4.59
5.12
2.18
1.00
N/R
1.49
0.98
2.92
1.46
3.06
3.35
1.34
1.66
1.25
0.71
4.59
1.33
1.85
1.42
0.74
1.08
1.69
1.09
0.93
0.96
3.07
3.03
19.98
3.21
1.52
10.91
2.80
17.76
2.68
1.09
1.06
6.07
2.31
3.09
1.70
1.18
2.73
1.46
1.87
2.07
1.84
1.09
1.36
15.23
1.95
4.79
19.34
2.06
1.37
3.29
0.73
0.72
0.62
Recal-A
OK-B 200
OK-B 200
OK-A
Recal-B
OK-A
Recal-B
OK-B 200
OK-A
OK-B 100
OK-A
OK-A
Recal-A
OK-A
Recal-A
OK-A
Recal-A
OK-A
Recal-A
Recal-B
Recal-A
Recal-A
Recal-A
Recal-A
Recal-B
Recal-A
Recal-B
Recal-A
Recal-B
Recal-A
Recal-B
Recal-B
OK-A
Recal-A
OK-B 400
Recal-B
OK-B 200
Recal-A
Recal-B
Recal-B
Recal-B
Recal-A
Recal-A
OK-B 250
Recal-B
OK-B 200
Recal-A
Recal-B
Recal-B
Recal-B
OK-A
Recal-B
Recal-B
Recal-B
Recal-A
Recal-A
(continued)
113
-------
Table B-4.
Continued
Manufacturer
Analyzer
Sorial Number
Foxboro
OVA-108
20868
Foxboro
OVA-128
41092
Foxboro
OVA-128
41102
Health
DP 111
1001
HMD
HW-101
See Text
Foxboro
Miran 1B2
322214
Compound/Calculated Response Factor
Acrylic acid"* 10.51
Methyl hydrazine" 5.47
Dimethyl formamide* 6.42
1,1-DimQthylhydrazIne 2.68
Acrytonitrile 1.55
1,3-Butadiene 2.41
Carbonyl sulfide* 103.95
Chtoromethyl-methyl ether* 7.77
50% CWoropyrene/xylene 1.46
Dichtoroethyl ether"* 22.12
Ethyl chloride 1.68
Ethylono dibromide 2.03
Ethylerte oxide* 2.40
Formalin 18.83
(37% formaldehyde/H20)
Methyl bromide 3.71
Methyl chloride 1.97
Vinyl bromide 2.14
ortho-Cresol
mota-Cresol"* 75.60
para-Cresol , N/R
Phenol (90% carboxy lie acid) 16.38
1,2,4-Trichlorobenzene 12.55
EthyRdene dichloride
2-Butoxyethanor** 19.37
2-Ethyoxyethanol* 3.55
1,4-Dich!orobenzone
Maleic anhydride
10.81
5.50
6.38
2.84
1.58
2.69
N/R
9.76
1.47
25.10
1.84
2.22
2.77
31.39
3.83
2.38
2.41
115.20
N/R
44.89
16.71
9.63
5.74
7.20
3.00
1.56
2.37
N/R
7.52
1.27
24.48
1.65
2.03
2.40
27.66
8.61
5.44
7.09
2.89
1.47
1.68
N/R
4.28
0.77
16.88
1.10
1.36
1.81
16.50
3.46 2.43
1.97 1.27
2.33 1.68
Solid—Not Tested
N/R N/R
N/R N/R
47.01 N/R
N/R 18.66
Not available in pure form from vendors
26.11 24.69 13.93
4.09 3.50 2.02
Solid—Not Tested
Solid—Not tested
•8.91
3.93
5.73
2.29
3.04
2.15
3.14
1.65
1.37
8.79
2.38
0.98
6.61
4.04
1.47
1.77
1.37
N/R
N/R
71.06
16.58
9.23
1.70
Recal-B
Recal-B
Recal-A
Recal-B
OK-B 100
OK-A
Recal-B
Recal-B
Recal-A
OK-A
Recal-A
OK-B 100
Recal-A
Recal-A
OK-A
Recal-B
- Recal-B
Recal-A
Recal-B
Recal-B
Recal-B
Recal-B
Recal-B
Recal-B
N/R
Miran 1B2
OK-A
OK-B
Rocal-A «
Rocal-8 «
No response or O/L = Off-Line
Low instrument response detected/high response factor calculated.
Unstable response and tailing of instrument strip chart record over time noted.
Volatility problem with compound.
Compound listed in Miran fixed library at/above 500 ppm.
Compound liste din Miran fixed library below 500 ppm, yet gave satisfactory results when tested at £100 ppm; the library range
is also listed.
Compound listed in Miran fixed library; most under 100 ppm but gave unsatisfactory results when tested at 500 ppm; required
rocalibration of Miran 1B2 for 500 ppm range.
Compound not listed in Miran fixed library and needs complete user listing, peak identification, and calibration of analyzer for
500 ppm.
114
-------
Appendix C
Bibliography
Equipment Leak Monitoring
1. Blacksmith, J.R. et al. Frequency of Leak Occurrence for
Fittings in Synthetic Organic Chemical Plant Process
Units. U.S. Environmental Protection Agency. Office of
Environmental Engineering and Technology, Research
Triangle Park, NC. Publication No. EPA 600/2-81-003.
2. Dubose, D.A. and Harris, G.E. Project Summary. Re-
sponse Factors of VOC Analyzers at a Meter Reading of
10,000 PPMV for Selected Organic Compounds. U.S.
Environmental Protection Agency. Industrial Environ-
mental Research Laboratory. Research Triangle Park,
NC. Publication No. EPA-600/S2-81-051. September
1981.
3. Dubose, D.A., Brown, G.E., and Harris, G.E. "Response
of Portable VOC Instruments to Chemical Mixtures."
U.S. Environmental Protection Agency. Publication EPA/
600-2-81-110. June 1981.
4. Hanzevack, K.M. "Fugitive Hydrocarbon Emissions -
Measurement and Data Analysis Methods. Proceedings:
Symposium/Workshop on Petroleum Refinery Emissions."
U.S. Environmental Protection Agency. Publication EPA-
600/2-78-199. September 1978.
5. Harvey, C.M., and Nelson, A.C., Jr., "VOC Fugitive
Emission Data-High Density Polyethylene Process Unit."
U.S. Environmental Protection Agency. Publication EPA-
600/2-81-109. June 1981.
6. U.S. Environmental Protection Agency, "Control of Vola-
tile Organic Compound Leaks from Petroleum Refinery
Equipment." Publication No. EPA-450/2-78-036. Re-
search Triangle Park, NC. June 1978.
7. Langley, G.J. et. al. "Analysis of SOCMI VOC Fugitive
Emissions Data.U.S. Environmental Protection Agency.
Publication No. EPA-600/ 2-81-111. June 1981.
8. Langley, G.J. and R.G. Wetherold. "Project Summary,
Evaluation of Maintenance for Fugitive VOC Emissions
Control." U.S. Environmental Protection Agency. Publi-
cation No. EPA-600/S2-81-080. July 1981.
9. Menzies, K.T., and Fasano, R.E., "Evaluation of Poten-
tial VOC Screening Instruments." U.S. Environmental
Protection Agency. Publication No. EPA-600/7-82-063.
November 1982.
10. Richards, J., and Hellwig, H. Portable Instrument User's
Manual for Monitoring VOC Sources. U.S. Environmen-
tal Protection Agency. Publication No. 340/1-86-015.
June 1988.
11.
U.S. Environmental Protection Agency, "Control of Vola-
tile Organic Compound Leaks from Synthetic Organic
Chemical and Polymer Manufacturing Equipment, Guide-
line Series." U.S. Environmental Protection Agency. Pub-
lication No. EPA 450/3-83-006. March 1984.
12. U.S. Environmental Protection Agency, Measurement of
Volatile Organic Compounds, Guideline Series. U.S. EPA
Publication No. EPA-450/278-041. Revised September
1979.
13. Wetherold, R.G., Provost, L.P.,and Smith, C.D. Assess-
ment of Atmospheric Emissions from Petroleum Refin-
ing: Volume 3, Appendix B. U.S. Environmental Protec-
tion Agency. Publication EPA 600/2-80-075c. April 1980.
115
•fr U.S. GOVERNMENT PRINTING OFFICE:1992-648-003/60076
-------
-------
-------
EPA/625/R-
cb
§
tJSg
832:
P
0 c
^ to
•05'
-- (D
? 0>
s* *"
5T
en
CD
o o m c
g S 3 i-
2. »• ^' CD
§ w o a.
S. g-i w
.-• -t CD 0>
i^is
ftl'?
^1 1
O> CD O
II
33 >
(D CO
W < =t a o
111 |i§
So o o-a-
• ~» 3 O ,
!i? ^
-o
m
33
T)
I
>D3
O C
O
------- |