v>EPA
United States
Environmental Protection
Agency
Technical Development Document
for the Final Effluent Limitations
Guidelines and New Source
Performance Standards for the Airport
Deicing Category
April 2012
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U.S. Environmental Protection Agency
Office of Water (4303T)
Engineering and Analysis Division
1200 Pennsylvania Avenue, NW
Washington, DC 20460
EPA-821-R-12-005
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Technical Development Document for Effluent
Limitation Guidelines and Standards for the Airport Deicing Category
ACKNOWLEDGMENTS AND DISCLAIMER
This document was prepared by the Environmental Protection Agency. Neither the United States
Government nor any of its employees, contractors, subcontractors, or their employees makes any
warranty, expressed or implied, or assumes any legal liability or responsibility for any third
party's use of or the results of such use of any information, apparatus, product, or process
discussed in this document, or represents that its use by such a party would not infringe on
privately owned rights.
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Technical Development Document for Effluent
Limitation Guidelines and Standards for the Airport Deicing Category
CONTENTS
Page
1. Legal Authority 1
1.1 Clean Water Act 1
1.1.1 Best Practicable Control Technology Currently Available (BPT) 1
1.1.2 Best Conventional Pollutant Control Technology (BCT) 1
1.1.3 Best Available Technology Economically Achievable (BAT) 1
1.1.4 New Source Performance Standards (NSPS) 2
1.1.5 Pretreatment Standards for Existing Sources (PSES) 2
1.1.6 Pretreatment Standards for New Sources (PSNS) 2
1.2 Effluent Guidelines Plan 3
2. Applicability and Subcategorization 4
2.1 Applicability of the Regulation 4
2.2 Subcategorization 4
2.2.1 ADF Usage 4
2.2.2 FAA Classification 5
2.2.3 Land Availability 5
2.2.4 Conclusions 5
3. Data Collection Activities 6
3.1 Preliminary Data Summary 6
3.2 Site Visits 6
3.3 Industry Questionnaires (Surveys) 9
3.3.1 Recipient Selection and Questionnaire Distribution 9
3.3.2 Questionnaire Information Collected 11
3.3.3 Questionnaire Review, Coding, and Data Entry 13
3.4 Field Sampling 14
3.5 Permit Review 14
3.5.1 Airport Selection for Permit Review 16
3.5.2 Obtaining NPDES Permits 16
3.5.3 Permit Review Process 16
3.6 Deicing Pad Costs 20
3.7 Industry-Submitted Data 20
3.8 Literature Reviews 22
3.8.1 Current Deicing Practices and Treatment Technologies 22
3.8.2 Current Airport Deicing Discharge Data 23
3.8.3 Chemical Information and Environmental Impact Studies 23
3.8.4 Current Deicing Discharge Regulations 23
3.9 Data Collected Based on Public Comments 24
3.9.1 EPA-Collected Data 24
3.9.2 Data Submitted with Public Comments 27
3.10 References 27
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Technical Development Document for Effluent
Limitation Guidelines and Standards for the Airport Deicing Category
CONTENTS (Continued)
Page
4. Overview of the Industry 28
4.1 Industry Statistics 28
4.1.1 Airports 28
4.1.2 Airlines 32
4.2 Industry Practices 34
4.2.1 Airfield Deicing Practices 34
4.2.2 Aircraft Deicing Practices 35
4.2.3 Airport Deicing Stormwater Collection and Control 38
4.2.4 Pollution Prevention Practices 39
4.3 References 41
5. Deicing Chemical Use and Deicing Stormwater Characterization 42
5.1 Deicing Chemical Usage 42
5.1.1 Airfield Chemical Use 42
5.1.2 Aircraft Chemical Use and Purchasing Patterns 43
5.2 Deicing Stormwater Characterization 43
5.2.1 Airfield Deicing Chemicals and Associated Deicing Stormwater 44
5.2.2 Aircraft Deicing Chemicals and Associated Deicing Stormwater 44
5.3 Aircraft and Airfield Deicing Chemical Use and Associated Deicing
Stormwater at Alaskan Airports 53
5.4 References 53
6. Pollutants of Concern 55
6.1 Identification of Airport Deicing/Anti-icing Stormwater Pollutants 55
6.2 Pollutants of Concern Selection Criteria 61
6.3 Identification of Potential Pollutants of Concern 61
6.4 Selection of Regulated Pollutants 64
6.5 References 66
7. Collection and Treatment Technologies Applicable to Airport Deicing
Operations 68
7.1 Deicing Stormwater Collection 68
7.1.1 Deicing Stormwater Collection and Conveyance 68
7.1.2 Deicing Stormwater Storage 72
7.2 Treatment 74
7.2.1 Biological Treatment 74
7.2.2 Physical Separation 78
7.3 Recycling 79
7.4 Pollution Prevention and Product Substitution Practices 80
7.5 References 86
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Technical Development Document for Effluent
Limitation Guidelines and Standards for the Airport Deicing Category
CONTENTS (Continued)
Page
8. Performance of Control and Treatment Scenarios 88
8.1 Deicing Pad Collection 88
8.2 Plug and Pump Collection with GCV 88
8.3 GCV Collection 89
8.4 AFB Treatment Performance 89
8.5 References 90
9. Pollutant Loadings and Pollutant Load Reduction Estimates 91
9.1 Data Sources 91
9.2 Aircraft Deicing Pollutant Loading 92
9.2.1 Estimate the Amount of Applied Deicing Chemical 92
9.2.2 Calculate the Amount of Pollutant Load Associated with the Applied
ADF 100
9.2.3 Estimate the Amount of Baseline Pollutant Load that is Discharged
Directly 101
9.2.4 Estimate Pollutant Loading Discharges for Each ADF
Collection/Control Scenario 102
9.2.5 Estimate Pollutant Loading Reductions for Each ADF
Collection/Control Scenario 102
9.3 Airfield Deicing Pollutant Loading 107
9.3.1 Estimate the Amount of Applied Deicing Chemical 107
9.3.2 Calculate the Amount of Pollutant Load Associated with the Applied
Chemical 112
9.3.3 Estimate the Amount of Baseline Pollutant Load that is Discharged
Directly 113
9.3.4 Estimate Pollutant Reductions for Each EPA Collection/Control
Scenario 113
9.4 References 115
10. Technology Costs 116
10.1 Costing Approach 116
10.2 Aircraft Deicing Costs 117
10.2.1 Overview of the ADF Collection and Treatment Airport Deicing Cost
Model 117
10.2.2 Airport Deicing Cost Model Equation Development 118
10.2.3 Development of Airport Deicing Cost Model Inputs 128
10.2.4 Airport Deicing Cost Model Design 129
10.2.5 Annualized Costs for ADF Collection and Treatment Alternatives 133
10.3 Airfield Deicing Costs 137
10.3.1 Urea and Potassium Acetate Chemical Costs and Application Rates 137
10.3.2 Mechanical Application Equipment and Storage of Potassium Acetate 139
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CONTENTS (Continued)
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10.4 Other ADF-Compliance-Related Costs 142
10.4.1 Assessing ADF Usage from Airport Tenants 143
10.4.2 Determination of ADF Stormwater Collection Percentage 143
10.4.3 Annual ADF Collection Equipment/System Inspections 146
10.4.4 COD Monitoring of On-Site Treatment Systems 147
10.5 Summary of Annualized Costs 148
10.6 References 153
11. Regulatory Options Considered And Selected For basis Of Final Regulation
155
11.1 BPT and BCT 155
11.2 BAT 155
11.2.1 Airfield Deicing: Product Substitution of Pavement Deicers
Containing Urea 156
11.2.2 Aircraft Deicing: ADF Collection Requirements and Effluent
Limitations 157
11.2.3 Options Considered for Today's Final Regulation for Identification of
BAT for ADF Collection and Discharge Requirements 158
11.2.4 BAT Options Selection 159
11.3 NSPS 160
11.4 PSESandPSNS 162
11.5 Reference s 162
12. Non-Water Quality Impacts 164
12.1 Energy Requirements 164
12.2 Air Emissions 166
12.2.1 Emissions from GCV Collection 166
12.2.2 Emissions from AFB Treatment Systems 168
12.3 Solid Waste Generation 168
12.4 Summary 169
12.5 References 169
13. Limitations and Standards : Data Selection and Calculation 171
13.1 Selected Pollutant Parameters 171
13.1.1 COD 171
13.1.2 Ammonia as Nitrogen (Ammonia) 171
13.2 Overview of Data Review and Selection 172
13.2.1 Data Selection Criteria 172
13.2.2 Other Considerations in Data Selection 174
13.3 Conventions for Modeling Multiple Data Sets from the Same Facility 175
13.4 COD: Data Selected as Basis of Final Limitations 176
13.4.1 Albany Treatment System 176
13.4.2 COD Data from EPA Sampling Episode at Albany 177
13.4.3 COD Self-Monitoring Data from Albany Airport 178
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Limitation Guidelines and Standards for the Airport Deicing Category
CONTENTS (Continued)
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13.5 Ammonia: Data Selected as Basis of Final Limitation 181
13.6 Limitations: Basis and Calculations 182
13.6.1 Definitions 183
13.6.2 Percentile Basis of the Limitations 183
13.6.3 Estimation Procedures for Percentiles 184
13.7 Achievability of Limitations 187
13.7.1 Statistical and Engineering Review of Limitations 188
13.7.2 Compliance with Limitations 190
13.8 References 192
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Technical Development Document for Effluent
Limitation Guidelines and Standards for the Airport Deicing Category
LIST OF TABLES
Page
3-1 Airports Vi sited 8
3-2 Deicing Questionnaire Response Rates 10
3-3 Airports Selected for Sampling and the Reason for Their Selection 15
3-4 Top 50 Airports in the United States with the Highest ADF Usage, Estimated
Based on SOFP Days and Total Airport Departures 17
3-5 Permit Review General Information Table 19
3-6 Permit Review Pollutant-Specific Information Table 20
3-7 Summary of Costing Data Provided by Industry 21
3-8 Summary of Long-Term Analytical Data Provided by Industry 21
3-9 Selected Airport Information Related to Deicing Pad Operations 25
4-1 Number of U.S. Airports by Airport Type in 2004 29
4-2 Deicing Airports by FAA Region for the Three Winter Seasons 30
4-3 Airline Classifications 33
4-4 National Estimate of Airports Using Deicing Chemicals or Materials 35
4-5 Deicing/Anti-Icing Chemicals Purchased by Airlines that Deiced Their Own
Aircraft 37
4-6 Deicing/Anti-Icing Chemicals Purchased for Aircraft Deiced by an FBO 37
4-7 Summary of Mechanical and Nonchemical Aircraft Deicing Methods Used by an
Airline 38
4-8 Summary of Mechanical and Nonchemical Aircraft Deicing Methods Used By
FBOs 38
4-9 Summary of Airport Collection, Containment, and Conveyance Methods 39
4-10 Summary of Airfield Pollution Prevention Practices 40
4-11 Summary of Aircraft Pollution Prevention Practices 40
5-1 U.S. Commercial Airports - National Estimate of Airfield Chemical Usage 42
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Technical Development Document for Effluent
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LIST OF TABLES (Continued)
Page
5-2 U.S. Commercial Airports - National Estimate of Aircraft Chemical Usage 1 43
5-3 EPA's Analytical Results for Pond 3E Effluent and Pond 6 Effluent, DTW 45
5-4 MSP and DTW Grab Sample Data Summary for Collected Deicing Stormwater 47
5-5 DEN, PIT, and ALB - 5-Day Average Data Summary for Untreated Deicing
Stormwater 49
5-6 RFD - 1-Day Data Summary for Untreated Deicing Stormwater 52
6-1 Pollutants Under Consideration as Potential Pollutants of Concern 57
6-2 Potential Pollutants of Concern Selected for Regulation 65
7-1 ADF Alternatives 82
9-1 ADF Estimates Based on Airline Detailed Questionnaire Responses 93
9-2 ADF Data Reported in the Airport Questionnaire 95
9-3 ADF Annual Usage Estimates for In-scope Airports 97
9-4 Theoretical Oxygen Demand Calculations for Aircraft Deicing Chemicals 100
9-5 ADF COD Baseline Loads and Loading Reductions for Each Control and
Treatment Scenario, by In-Scope Airport 103
9-6 Three-Year Average Amount of Pavement Deicing Chemical Usage, in Pounds 108
9-7 ThOD Calculations for Airfield Deicing Chemicals 112
9-8 Baseline Ammonia and COD Load and Potential Load Reduction Associated with
the Discontinued Use of Urea as an Airfield Deicing Chemical for In-Scope
Airports 114
10-1 GCV Capital and O&M Costs 121
10-2 Normalized Capital and O&M Costs for the Plug and Pump Collection System 122
10-3 Estimated Cost for 10,000 Linear Feet of Stormwater Piping 124
10-4 Storage Tank Volumes and Installed Capital Cost for Various Airports 125
10-5 Normalized Annual O&M Costs for the AFB Reactors 127
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Technical Development Document for Effluent
Limitation Guidelines and Standards for the Airport Deicing Category
LIST OF TABLES (Continued)
Page
10-6 Airport Deicing Cost Model Equations, Input Variables, and Assumptions 131
10-7 Annualized Costs by Model Facility for Control and Treatment 134
10-8 Average Cost for Urea and Potassium Acetate, 2002-2005 138
10-9 Typical Application Rates for Potassium Acetate 138
10-10 Application Rates for Sodium Acetate and Urea 138
10-11 Cost for Application of Urea and Potassium Acetate, per 1000 Square Feet 139
10-12 Application Equipment Costs for Liquid Pavement Deicer 140
10-13 Storage Tank Capital Costs for Liquid Pavement Deicer 141
10-14 Annualized Costs for In-Scope Airports to Change from Urea to Potassium
Acetate for Airfield Deicing 142
10-15 Other Compliance-Related Costs by Airport 144
10-16 Summary of EPA's Annualized Costs for ADF Collection and Treatment, Airfield
Deicing Urea Substitution, and Other Compliance-Related Costs 149
11-1 Final Rule BAT Annualized Costs and Load Removals for In-Scope Airports 156
12-1 Potential Electricity Generation from AFB Biogas Generation 166
12-2 Estimated Incremental Pollutant Emissions from GCVs 167
12-3 Potential Air Emissions from AFB Treatment Systems 168
12-4 Estimated Sludge Generation from AFB Bioreactors Treating ADF-Contaminated
Stormwater 169
13-1 COD: EPA and Albany Airport Self-Monitoring Effluent Data Collected During
EPA's Sampling Episode 178
13-2 COD: Dates Excluded Because Units Operated in Series 179
13-3 COD: Dates Excluded Because Influent Concentration Reported as Zero 179
13-4 COD: Dates Excluded Because of Performance Excursions 180
13-5 COD: Summary of Albany Airport Self-Monitoring Effluent Data After
Exclusions 181
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Technical Development Document for Effluent
Limitation Guidelines and Standards for the Airport Deicing Category
LIST OF TABLES (Continued)
Page
13-6 Ammonia: Data from Albany Airport Used to Develop Limitations 182
13-7 COD and Ammonia: Final Limitations with Long-Term Averages and Variability
Factors 185
13-8 COD: 99th Percentile Estimates from Each Treatment Unit 185
13-9 COD: Effect of Number of Daily Values in Weekly Averages 186
13-10 Ammonia: Consideration of Autocorrelation for Final Limitations, Long-Term
Averages, and Variability Factors 187
13-11 COD: Dates and Values Greater than Final Limitation of 271 mg/L 189
13-12 COD: Summary Statistics of Influent Concentrations 190
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Technical Development Document for Effluent
Limitation Guidelines and Standards for the Airport Deicing Category
LIST OF FIGURES
Page
4-1 Percentage of Airports Deicing Airfield Pavement Each Month 31
4-2 Discharge Status of Airports 32
7-1 Deicing Pad Equipped with Fixed Deicing Booms at Pittsburgh Airport 69
7-2 GCV 71
7-3 Pond for Deicing Stormwater Storage 73
7-4 Frac Tanks 74
7-5 Aerated Pond Installation at Portland Airport 76
7-6 Typical Anaerobic Fluid Bed Treatment System for Treatment of ADF-
Contaminated Stormwater 77
7-7 Infrared Hangar at JFK 81
9-1 ADF Factor vs. PG/EG Gallons for U.S. Airports (excluding Alaska) 95
9-2 ADF Factor vs. PG/EG Gallons for Alaskan Airports 96
10-1 AFB Reactor Capital Cost for Treating ADF-Contaminated Stormwater 126
13-1 Simplified Drawing of Albany Airport Treatment System and Sample Points 177
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Technical Development Document for Effluent
Limitation Guidelines and Standards for the Airport Deicing Category
Section 1 - Legal Authority
1. Legal Authority
Effluent limitation guidelines and standards for the Airport Deicing Category are
promulgated under the authority of sections 301, 304, 306, 307, 308, and 501 of the Clean Water
Act, 33 U.S.C. 1311, 1314, 1316, 1317, 1318, and 1361.
1.1 Clean Water Act
Congress passed the Federal Water Pollution Control Act Amendments of 1972, also
known as the Clean Water Act (CWA), to "restore and maintain the chemical, physical, and
biological integrity of the Nation's waters" (section 101(a)). To implement the Act, the United
States Environmental Protection Agency (EPA) is to issue effluent limitation guidelines,
pretreatment standards, and new source performance standards for industrial dischargers. These
guidelines and standards are summarized briefly in the following sections.
1.1.1 Best Practicable Control Technology Currently Available (BPT)
Traditionally, EPA establishes BPT effluent limitations based on the average of the best
performances of facilities within the industry, grouped to reflect various ages, sizes, processes, or
other common characteristics. EPA may promulgate BPT effluent limits for conventional, toxic,
and nonconventional pollutants. In specifying BPT, EPA looks at a number of factors. EPA first
considers the cost of achieving effluent reductions in relation to the effluent reduction benefits.
The Agency also considers the age of the equipment and facilities, the processes employed,
engineering aspects of the control technologies, and required process changes, non-water-quality
environmental impacts (including energy requirements), and such other factors as the
Administrator deems appropriate. See CWA section 304(b)(1)(B)). If, however, existing
performance is uniformly inadequate, EPA may establish limitations based on higher levels of
control than are currently in place in an industrial category when based on an Agency
determination that the technology is available in another category or subcategory, and can be
practically applied.
1.1.2 Best Conventional Pollutant Control Technology (BCT)
The 1977 amendments to the CWA required EPA to identify additional levels of effluent
reduction for conventional pollutants associated with BCT technology for discharges from
existing industrial point sources. In addition to other factors specified in section 304(b)(4)(B),
the CWA requires that EPA establish BCT limitations after consideration of a two-part "cost-
reasonableness" test. EPA explained its methodology for the development of BCT limitations in
July 1986 (51 FR 24974). Section 304(a)(4) designates the following as conventional pollutants:
biochemical oxygen demand over 5 days (BOD5), total suspended solids (TSS), fecal coliform,
pH, and any additional pollutants defined by the Administrator as conventional. The
Administrator designated oil andgrease as an additional conventional pollutant on July 30, 1979
(44 FR 44501; 40 CFR 401.16).
1.1.3 Best Available Technology Economically Achievable (BAT)
BAT represents the second level of stringency for controlling direct discharge of toxic
and nonconventional pollutants. In general, BAT effluent limitation guidelines represent the best
economically achievable performance of facilities in the industrial subcategory or category. The
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Technical Development Document for Effluent
Limitation Guidelines and Standards for the Airport Deicing Category
Section 1 - Legal Authority
factors considered in assessing BAT include the cost of achieving BAT effluent reductions, the
age of equipment and facilities involved, the process employed, potential process changes, and
non-water quality environmental impacts including energy requirements, and such other factors
as the Administrator deems appropriate. The Agency retains considerable discretion in assigning
the weight to be accorded these factors. An additional statutory factor considered in setting BAT
is economic achievability. Generally, EPA determines economic achievability based on total
costs to the industry and the effect of compliance with BAT limitations on overall industry and
subcategory financial conditions. As with BPT, where existing performance is uniformly
inadequate, BAT may reflect a higher level of performance than is currently being achieved
based on technology transferred from a different subcategory or category. BAT may be based
upon process changes or internal controls, even when these technologies are not common
industry practice.
1.1.4 New Source Performance Standards (NSPS)
NSPS reflect effluent reductions that are achievable based on the best available
demonstrated control technology. New facilities have the opportunity to install the best and most
efficient production processes and wastewater treatment technologies. As a result, NSPS should
represent the most stringent controls attainable through the application of the best available
demonstrated control technology for all pollutants (i.e., conventional, nonconventional, and
priority pollutants). In establishing NSPS, EPA is directed to take into consideration the cost of
achieving the effluent reduction and any non-water quality environmental impacts and energy
requirements.
1.1.5 Pretreatment Standards for Existing Sources (PSES)
Pretreatment standards apply to discharges of pollutants to publicly owned treatment
works (POTWs) rather than to discharges to waters of the United States. PSES are designed to
prevent the discharge of pollutants that pass through, interfere with, or are otherwise
incompatible with the operation of POTWs. Categorical pretreatment standards are technology-
based and analogous to BAT effluent limitation guidelines. The General Pretreatment
Regulations, which set forth the framework for the implementation of categorical pretreatment
standards, are found at 40 CFR Part 403. These regulations establish pretreatment standards that
apply to all nondomestic dischargers. See 52 FR 1586 (January 14, 1987).
1.1.6 Pretreatment Standards for New Sources (PSNS)
Section 307(c) of the Act calls for EPA to promulgate PSNS at the same time it
promulgates NSPS. Such pretreatment standards must prevent the discharge of any pollutant into
a POTW that may interfere with, pass through, or may otherwise be incompatible with the
POTW. EPA promulgates categorical PSES based principally on BAT technology for existing
sources. EPA promulgates PSNS based on best available demonstrated technology for new
sources. New indirect discharges have the opportunity to incorporate into their facilities the best
available demonstrated technologies. The Agency considers the same factors in promulgating
PSNS as it considers in promulgating NSPS.
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Technical Development Document for Effluent
Limitation Guidelines and Standards for the Airport Deicing Category
Section 1 - Legal Authority
1.2 Effluent Guidelines Plan
In 2004, EPA issued its biannual effluent guidelines plan under section 304(m) of the
CWA. This plan announced the initiation of rulemaking for the Airport Deicing Category (69 FR
53705, September 2, 2004).
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Technical Development Document for Effluent
Limitation Guidelines and Standards for the Airport Deicing Category
Section 2 - Applicability and Sub categorization
2.
Applicability and Subcategorization
This document presents the information and rationale supporting the effluent limitation
guidelines and standards for the Airport Deicing Category. Section 2 highlights the applicability
and subcategorization basis of this regulation.
Airports in the scope of this regulation are defined as Primary Commercial Airports that
conduct deicing activities.
The CWA requires EPA to consider a number of different factors when developing
effluent limitation guidelines. For example, when developing limitations that represent the BAT
for a particular industrial category, EPA must consider among other factors the following: the
age of the equipment and facilities in the category, location, manufacturing processes employed,
types of treatment technology to reduce the effluent discharges, costs of effluent reductions, and
non-water-quality impacts (CWA section 304(b)(2)(B)). The statute also allows EPA to take into
account other factors that the EPA Administrator deems appropriate and requires the BAT model
technology chosen by EPA to be economically achievable, which generally involves considering
both compliance costs and overall financial condition of the industry.
For this rulemaking, EPA evaluated the characteristics of the Airport Deicing Category to
determine their potential to provide the Agency with a means to differentiate effluent quantity
and quality among facilities. EPA also evaluated the design, process, and operational
characteristics of the different industry segments to determine technology control options that
might be applied to reduce effluent quantity and improve effluent quality. Based on this analysis,
below are the factors that EPA evaluated to determine whether subcategorizing the Airport
Decicing Category would be appropriate:
Aircraft deicing fluid (ADF) usage;
Federal Aviation Administration (FAA) classifications; and
Land availability.
2.2.1 ADF Usage
Ethylene glycols (EG) and propylene glycols (PG) are the main ingredients in ADF.
Through EPA's research, it became apparent that the volume of glycol required to deice a single
aircraft varied greatly depending on a number of variables including weather conditions, aircraft
size, and operator training. EPA reviewed industry questionnaire responses and determined that
ADF usage is the best indicator for the volume of deicing operations that occur at an airport.
ADF usage can range from zero to hundreds of thousands of gallons per year at airports across
the United States.
2.1
Applicability of the Regulation
2.2
Subcategorization
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Technical Development Document for Effluent
Limitation Guidelines and Standards for the Airport Deicing Category
Section 2 - Applicability and Sub categorization
2.2.2 FAA Classification
The Airport and Airway Improvement Act (AAIA) and the FAA classify airports by size
based on the volume of commercial traffic. (Noncommercial airports, commonly known as
"General Aviation" airports, are not specifically defined by the AAIA.) EPA utilized this
classification system to organize its data collection and analysis of the aviation industry. The
AAIA defines airports by categories of airport activities, including Commercial Service (Primary
and Nonprimary), Cargo Service, and Reliever. Commercial Service Airports are publicly owned
airports that have at least 2,500 passenger boardings each calendar year and receive scheduled
passenger service. The definition also includes passengers who continue on an aircraft in
international flight that stops at an airport in any of the 50 states for a nontraffic purpose, such as
refueling or aircraft maintenance rather than passenger activity. Primary Commercial Service
airports have more than 10,000 passenger boardings each year. Primary Commercial Service
airports are further subdivided into Large Hub, Medium Hub, Small Hub, and Non-hub
classifications, based on the percentage of total passenger boardings within the United States in
the most current calendar year ending before the start of the current fiscal year.
Early in the regulatory process, EPA assumed that the majority of the deicing in the
United States would occur at Primary Commercial Service airports and particularly those with
nonpropeller departures. General aviation aircraft, as well as smaller commercial propeller
driven aircraft are expected to suspend flights during inclement weather, whereas commercial
aircraft with scheduled service are much more likely to deice to meet customer demands.
2.2.3 Land Availability
EPA is aware that airports across the country have different amounts of land that may be
available for facility modifications, such as installing environmental controls. EPA collected
some basic information from airports on their current configurations. However, neither the
aviation industry nor the FAA has developed a standard definition of land availability.
As part of the public comments on the proposed rule, commenters requested that EPA
subcategorize airports that would be prohibited from installing deicing pads due to gate, runway,
and taxiway space constraints and lack of available land. EPA did not set a spent ADF collection
requirement as part of BAT in the final rule and therefore did not separate these airports into
their own subcategory.
2.2.4 Conclusions
EPA concludes that establishing formal subcategories is not necessary for the Airport
Deicing Category; rather, EPA structured the applicability of the final rule to address the relevant
factors and established a set of requirements that encompasses the range of situations that an
airport may encounter during deicing operations.
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Technical Development Document for Effluent
Limitation Guidelines and Standards for the Airport Deicing Category
Section 3 - Data Collection Activities
3. Data Collection Activities
To characterize airport deicing operations and to develop the final effluent limitation
guidelines and standards, EPA collected and evaluated technical and economic data from a
variety of sources. This section describes the following data sources used for the Airport Deicing
Category rulemaking effort:
Section 3.1 - Preliminary Data Summary
Section 3.2 - Site Visits
Section 3.3 - Industry Questionnaires (Surveys)
Section 3.4 - Field Sampling
Section 3.5 - Permit Review
Section 3.6 - Deicing Pad Costs
Section 3.7 - Industry-Supplied Data
Section 3.8 - Literature Reviews
Section 3.9 - Data Collected as Part of Public Comments
3.1 Preliminary Data Summary
EPA's initial source of wastewater discharge information for the aviation industry was
the Preliminary Data Summary (PDS): Airport Deicing Operations, which was published in
August 2000 (USEPA, 2000). This study focused on approximately 200 U.S. airports with
potentially significant deicing/anti-icing operations. For the study, EPA collected information
from industry questionnaires, engineering site visits, wastewater sampling activities, meetings
with industry and regulatory agencies, and technical and scientific literature. See Section 3.0 of
the PDS for detailed information on the study's data collection activities.
The questionnaires that EPA reviewed included the 1993 Screener Questionnaire for the
Transportation Equipment Cleaning Industry and a set of questionnaires distributed during the
study to major and regional airports and airlines, technology vendors, and POTWs.
From September 1997 through March 1999, the Agency conducted 16 airport site visits
and six sampling episodes to collect information about deicing processes, deicing equipment, and
deicing wastewater generation, collection, handling, and treatment technologies.
EPA met with the FAA, deicing fluid manufacturers and formulators, airlines, industry
associations, technology vendors, and other interested parties to discuss environmental and
operational issues related to aircraft deicing and anti-icing operations.
Literature searches provided information on the toxicity, industry usage, and mitigation
techniques for ADFs. The literature also covered topics such as alternative fluid types, pollution
prevention practices, economic and financial data, and environmental impacts.
3.2 Site Visits
Between December 2004 and November 2005, EPA conducted 20 airport site visits to
collect current information about aircraft and airfield deicing practices, deicing equipment,
deicing stormwater generation, collection, handling, and control. During these site visits, EPA
also evaluated potential sampling locations for the sampling program described in Section 3.4.
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Section 3 - Data Collection Activities
EPA used information collected from the PDS, updated airport literature searches, and
other Agency-supplied data to assess potential airports for site visits. EPA also solicited
recommendations from industry trade associations, including the Air Transport Association
(ATA), the American Association of Airline Executives (AAAE) and Airports Council
International-North America (ACI-NA). EPA considered the following criteria in evaluating
which airports to visit:
Hub size and location of the airport;
ADF handling practices;
Deicing stormwater collection and control practices; and
ADF-contaminated stormwater discharge practices.
In general, EPA visited Medium Hub and Large Hub airports operating in northern
climates that conduct aircraft and airfield deicing operations each winter. EPA also visited some
Small Hub airports to evaluate potential issues related to an airport's size. The Agency visited
airports that use a variety of deicing practices (such as gate deicing, centralized deicing pads
(CDPs), deicing trucks and stationary booms, infrared deicing hangars) and various deicing
stormwater collection and control technologies (such as dedicated deicing stormwater collection
systems, stormwater treatment through biological systems, and glycol recovery systems). Table
3-1 lists the 20 airports visited in 2004 and 2005, the visit dates, and EPA's rationale for
selecting each for a site visit. This table also lists a post-proposal site visit conducted at Boston
Logan airport.
During the site visits, EPA collected the following information:
General airport and deicing operations information, including size and age of the
airport, permit status, information on the entities that perform deicing operations
(both aircraft and airfield), and current airline tenant information;
Description of the deicing/anti-icing operations conducted at the airport, including
the types of equipment used, locations of deicing operations, and information on
any pollution prevention or "state-of-the-art" systems in use at the airport that
improved their deicing operations;
Deicing chemicals used, including ADF type (e.g., Type I-IV), pavement deicer
type, and any chemical usage information available;
Description of the deicing stormwater collection and control systems used at the
airport, including any glycol recovery or stormwater treatment systems and their
effectiveness and any available cost information for these systems; and
Airport monitoring and discharge of deicing stormwater, including pollutants
monitored and frequency of monitoring.
This information is documented in the Site Visit Report (SYR) for each airport visited.
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Section 3 - Data Collection Activities
Table 3-1. Airports Visited
Airport Name
Airport
Code
Date of Visit
Airport Details
Washington Dulles
International
IAD
12/1/2004
Local Large Hub airport, ADF-contaminated
stormwater collection and glycol recovery, indirect
discharger
Baltimore-Washington
International
BWI
12/15/2004
Local Large Hub airport, deicing pads, ADF-
contaminated stormwater collection, indirect
discharger
Chicago O'Hare
International
ORD
1/26/2005
Large Hub airport, ADF-contaminated stormwater
collection with indirect discharge, upgrades to system
since the PDS site visit
General Mitchell
International
(Milwaukee)
MKE
1/27/2005
Medium Hub airport, ADF-contaminated stormwater
collection and indirect discharge, extensive monitoring
data in collaboration with U.S. Geological Survey
(USGS)
Detroit Metropolitan
Wayne County
DTW
1/28/2005
Large Hub airport, deicing pads, ADF-contaminated
stormwater collection with glycol recovery, both direct
and indirect discharger
Ronald Reagan
Washington National
DCA
2/1/2005
Local Large Hub airport, changes in ADF practices
since PDS site visit, ADF-contaminated stormwater
collection
Syracuse Hancock
International
SYR
2/9/2005
Small Hub airport, deicing pads, aerated stormwater
lagoons, indirect discharger
Albany International
ALB
2/10/2005
Small Hub airport, ADF-contaminated stormwater
collection with anaerobic and aerobic treatment, direct
discharger, upgrades to system since PDS site visit
Pittsburgh International
PIT
2/10/2005
Large Hub airport, deicing pads, glycol recovery and
treatment (ultra filtration and reverse osmosis) of ADF-
contaminated stormwater, direct discharger
Cincinnati/Northern
Kentucky International
CVG
2/11/2005
Large Hub airport, variety of ADF-contaminated
stormwater-related activities, recommended by FAA as
a site visit location, on-site aerobic treatment, direct
and indirect discharger
Richmond International
RIC
2/16/2005
Local Small Hub airport
Minneapolis/St. Paul
International/World-
Chamberlain
MSP
2/18/2005
Large Hub airport, ADF collection with glycol
recovery, direct and indirect discharger
James M Cox Dayton
International
DAY
2/25/2006
Small Hub airport, centralized deicing with ADF-
contaminated stormwater collection
Portland International
(Oregon)
PDX
7/26/2005
Medium Hub northwestern airport, indirectly
discharges high-strength deicing stormwater, sends
low-strength deicing stormwater to detention pond and
then to direct discharge
Seattle-Tacoma
International
SEA
7/27/2006
Large Hub northwestern airport, industrial stormwater
treatment on site
LaGuardia (New York)
LGA
10/11/2005
Large Hub airport, direct discharger, part of New York
City area visits
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Section 3 - Data Collection Activities
Table 3-1 (Continued)
Airport Name
Airport
Code
Date of Visit
Airport Details
John F. Kennedy
International (New
York)
JFK
10/11/2005
Large Hub airport with a high percentage of
international flights, direct discharger, part of New
York City area visits, future plans for infrared deicing
Newark Liberty
International
EWR
10/12/2005
Large Hub airport, infrared deicing technology since
1999
Salt Lake City
International
SLC
11/8/2005
Large Hub western airport, ADF-contaminated
stormwater collection with glycol recovery
Denver International
DEN
11/9/2005
Large Hub western airport, deicing pads, ADF-
contaminated stormwater collection with glycol
recovery
General Edward
Lawrence Logan
International
BOS
3/21/2011
Space-constrained airport with no ADF-contaminated
stormwater collection and direct discharge
3.3 Industry Questionnaires (Surveys)
EPA distributed three questionnaires to directly support the Airport Deicing rulemaking.
Section 3.3.1 discusses the recipient selection process, distribution, and mail-out results for the
three airport deicing questionnaires. Section 3.3.2 discusses the organization of and type of
technical information requested in each questionnaire.
3.3.1 Recipient Selection and Questionnaire Distribution
EPA distributed a screener questionnaire followed by a detailed airline questionnaire to
airlines, and a questionnaire to airports. The overall focus of the questionnaires was on airports
and airlines that perform deicing and anti-icing on aircraft and/or airfield pavement. EPA
selected airports for the airport questionnaire by airport type (i.e., Large Hub, Medium Hub,
Small Hub, and Non-hub), days and amount of snow or freezing precipitation, and the number of
departures. EPA performed a census design for large and Medium Hub1 airports and a stratified
random sample design for small and Non-hub airports (see the Statistical Support Memorandum
DCN AD01208).
EPA selected recipients for the airline screener questionnaire by identifying airlines with
greater than 1,000 departures per year at those airports selected for the airport questionnaire.
EPA selected airlines for the detailed airline questionnaire based on the airline screener
questionnaire responses (which identified whether an airline deiced its aircraft or used some
other entity) at the specified airports. To reduce respondent burden, EPA asked the selected
1FAA classifies large commercial airports into size categories of "hubs," based on the number of annual
enplanements that occur at the airport. Enplanements represent the number of passengers boarding the plane for
departure. Large Hubs are airports that represent more than 1 percent of total U.S. passenger enplanements. Medium
Hubs are airports that account for more than 0.25 percent but less than 1 percent of total passenger enplanements.
Small Hubs enplane 0.05 to 0.25 percent of the total passenger enplanements. Airports with less than 0.05 percent of
the total passenger enplanements but more than 10,000 annual enplanements are considered Non-hub primary
airports.
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airlines to provide data on a limited subset of the airports they served for which they were
expected to use the maximum amount of deicing chemicals.
Table 3-2 summarizes the number of questionnaires distributed in each category and their
response rates.
Table 3-2. Deicing Questionnaire Response Rates
Questionnaire Type
Distributed
Retu rned
Undelivered
Retu rned
Completed
Not Retu rned
Airport Deicing Questionnaire
153
0 (0%)
150 (98%)
3 (2%)1
Airline Screener Questionnaire2
72
1 (1%)
70 (97%)
1 (1%)
Airline Deicing Detailed Questionnaire
58
0 (0%)
49 (84%)
9 (16%)
EPA determined that one airport recipient was out of scope and removed it from the sample frame.
2 Information was collected from an additional 22 foreign carriers.
3.3.1.1 Airport Questionnaire
EPA selected 153 airports to receive the airport questionnaire and distributed the
questionnaire to these airports in April 2006. Of the 153 airport questionnaires distributed, 150
were completed and returned. EPA removed one of the three nonrespondent airports from the
sample frame because it was a city airport operating as a tenant at a military airport. EPA
determined that its selection was based on data for the military airport operations, not the city
airport, and military airports were not included in the sample frame.
3.3.1.2 Airline Screener Questionnaire
EPA initially selected 72 airlines as recipients of the screener questionnaire. The recipient
group comprised a random sample of airlines with greater than 1,000 departures per year
operating at the airports selected for the airport questionnaire. In April 2006, the Agency
distributed the airline screener questionnaire to the 72 airlines. EPA also identified 22 additional
foreign airlines for which information would be useful in developing effluent guidelines, but that
were not captured by the random sample. EPA collected aircraft deicing and anti-icing
information for these 22 foreign carriers through contacts with airport managers where the
carriers operated.
Of the 72 screener questionnaires distributed, 70 were completed and returned to EPA.
Of the two not returned, one questionnaire was returned undelivered, as the airline had ceased
operations.
3.3.1.3 Airline Detailed Questionnaire
Using the responses from the airline screener questionnaire, EPA selected and sent a
more detailed questionnaire to 58 airlines that responded they deice planes at any of the airports
that received an airport questionnaire. This questionnaire was distributed in March 2007. The
selection included 448 airline/airport combinations. The Agency categorized the airline/airport
combinations according to the entity that performed most of the deicing for the 2002/2003,
2003/2004, and 2004/2005 winter seasons as listed below:
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Airline/airport combinations that deice their own aircraft;
Airline/airport combinations that contract to fixed-base operators (FBOs) for
deicing services; or
Airline/airport combinations that contract to other airlines for deicing services.
Of the 58 airline detailed questionnaires sent, 49 were completed returned and nine were
not returned.
3.3.2 Questionnaire Information Collected
EPA designed the questionnaires to collect current information with sufficient detail to
support development of effluent guidelines. The questionnaires collected information on deicing
operations performed on aircraft and airfield pavement, including deicing stormwater generation,
collection, characterization, management, and treatment. The airline screener supported the
selection of recipients for the airline detailed questionnaire. This section describes the technical
information collected and the purpose of each of the three questionnaires.
3.3.2.1 Airport Questionnaire
EPA divided the airport deicing questionnaire into the following parts and sections:
PART A: TECHNICAL INFORMATION
Section 1: General Airport Information
Section 2: Airport Deicing and Anti-Icing Operations
Section 3: Deicing Stormwater Containment and/or Collection
Section 4: Deicing Stormwater Treatment/Recovery
Section 5: Analytical Data
Section 6: Pollution Prevention Practices
PART B: FINANCIAL AND ECONOMIC INFORMATION
Section 1: Ownership and Management Structure
Section 2: Airport Finances
Section 3: Capital Expenditures
Section 4: Airport Operations
Part A, Section 1 (Questions 1 through 24) requested information to identify the airport
and primary contacts, to confirm that aircraft deicing/anti-icing was performed during the three
designated winter seasons (2002/2003, 2003/2004, and 2004/2005), and to characterize deicing
operations. This information included the destination of deicing/anti-icing stormwater, receiving
surface waters, the entity that performed aircraft and/or airfield pavement deicing, and the
number of deicing/anti-icing days per winter season. This information helped EPA update the
industry profile on airports deicing in the U.S., characterize deicing/anti-icing operations, and
determine the proximity and types of ecosystems within and beyond airport boundaries
Part A, Section 2 (Questions 25 through 31) requested detailed information about airport
deicing/anti-icing stormwater sources, flows, and destinations as well as deicing/anti-
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icingchemicals, materials, and practices. EPA used this information to develop an industry
profile of deicing stormwater generation and collection, to determine baseline loadings using
airfield deicing chemical usage, and to develop and evaluate possible regulatory technology
options and compliance cost estimates.
Part A, Section 3 (Questions 32 through 39) requested information on the collection,
containment, conveyance, discharge and/or disposal methods for deicing stormwater, and
pollution prevention and best management practices. EPA used this information to develop an
industry profile of deicing stormwater collection/containment/conveyance methods and to
evaluate pollution prevention and best management practices.
Part A, Section 4 (Questions 40 through 51) requested information on deicing stormwater
treatment technologies and units operated by the airport, including deicing stormwater treatment
diagrams, design and operating specifications, sources of wastewater influent, treatment
chemical additions, treatment operations and maintenance costs, and discharge practices. EPA
used this information to develop control technology options, regulatory options, and compliance
cost estimates.
Part A, Section 5 (Questions 52 through 55) requested information concerning the
availability of deicing stormwater characterization data, receiving water in-stream monitoring
data, and/or data characterizing the effectiveness of treatment of deicing stormwater. EPA used
this information to follow up with selected airports to request long-term monitoring data, to
estimate pollutant discharge loadings, to characterize behavior of the discharge in the receiving
water, to assess deicing stormwater treatment technologies, and to assess environmental impacts.
Part A, Section 6 (Questions 56 through 68) requested information to evaluate the status
of pollution prevention practices at each airport and to identify pollution prevention
technologies. EPA used this information to identify appropriate practices as regulatory options
and to prepare an industry profile of pollution prevention practices.
Part B of the questionnaire requested airport financial and economic information.
Section 1 requested information on the ownership and management structure that EPA used to
develop the industry profile and to estimate economic impacts of an effluent guideline. Section 2
requested information on operation finances that EPA used to project the potential impacts of the
rule. Section 3 requested information on current capital airport expenditures that EPA used to
assess the capability of airports to pay for deicing-related capital improvements. Section 4
requested information on the finances for airport operations, including the airport's financial
statement, which EPA used to determine the airport's cost of capital.
3.3.2.2 Airline Screener Questionnaire
The airline screener questionnaire included three questions. Question 1 requested the
contact information for the airline should EPA need to verify or clarify their response. Question
2 asked who (the airline, another airline, FBO, or private contractor) performed most of the
deicing/anti-icing on the respondent's aircraft at specific airports. Question 3 provided an
opportunity for the respondent to provide additional information or comment on its responses.
EPA used this information to identify potential airline detailed questionnaire recipients and to
indicate the potential contribution of FBOs to deicing operations and to the discharge of ADF-
contaminated stormwater.
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3.3.2.3 Airline Detailed Questionnaire
EPA divided the airline detailed questionnaire into the following parts and sections:
PART A:
TECHNICAL INFORMATION
Section 1:
General Airline Information
Section 2:
Airline Deicing and Anti-Icing Operations (at each airport specified in
Section 1)
Section 3:
Pollution Prevention Practices (at each airport specified in Section 1)
PART B:
DEICING COSTS AND OPERATIONS
Section 1:
Airline Deicing Costs and Operations
Section 2:
Airport-Specific Deicing Costs and Operations
Part A, Section 1 (Questions 1 through 4) requested verification of the airline name and
address and identification of the primary and secondary contacts to clarify or verify the technical
questionnaire responses.
Part A, Section 2 (Questions 5 through 18) requested information on deicing/anti-icing
operations performed by the airline or for the airline at each specified airport. The Agency used
this information to:
Develop an industry profile of ADF usage and deicing stormwater generation;
Estimate pollutant loadings;
Characterize deicing stormwater;
Evaluate differences in airport deicing stormwater generation and characteristics;
Identify pollutants of concern; and
Identify opportunities for pollution prevention through chemical substitution and
best management practices.
Part A, Section 3 (Questions 19 through 31) requested information on the airline's
pollution prevention practices including a description of each practice and any costs and/or
savings from its implementation. The Agency evaluated this information to identify appropriate
practices that could become part of regulatory options and to develop an industry profile.
Part B of the questionnaire requested airline financial and economic information.
Section 1 requested information on ownership, aircraft deicing costs and operations, and the
airline's financial statement, that EPA used to develop the industry economic profile and to
conduct the economic analysis. Section 2 requested detailed information regarding airline-
specific deicing costs and operations at specific airport locations. The Agency also used this
information for the industry economic profile and to determine the economic impacts of the rule.
3.3.3 Questionnaire Review, Coding, and Data Entry
EPA reviewed the screener and the two detailed questionnaires for completeness,
accuracy, and consistency of the responses. In some cases, the Agency followed up with the
airport or airline by email or telephone to clarify responses or to obtain missing or incomplete
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information. During the review, EPA coded responses to facilitate entry of data into the airline
screener and the airline and airport questionnaire databases.
The Agency developed databases containing the information provided by questionnaire
respondents of each questionnaire. After detailed review and coding, EPA entered data from the
questionnaires into the appropriate database using a double-key-entry and verification procedure
to identify and resolve differences between the two data entry tasks.
3.4 Field Sampling
EPA conducted sampling episodes at six airports from March 2005 through August 2006
to characterize ADF and ADF-contaminated storm water discharges and to evaluate treatment
technologies for stormwater affected by aircraft and airfield deicing practices. EPA used existing
industry profile information and information collected during airport site visits to determine the
most appropriate locations for sampling. The Agency evaluated the following criteria for
selecting sampling sites:
Size and location of the airport;
Deicing stormwater collection and control practices; and
ADF-contaminated stormwater discharge practices.
EPA conducted the episodes to characterize deicing stormwater and assess the
capabilities and effectiveness of several different treatment technologies such as anaerobic
treatment, aerobic treatment, distillation, reverse osmosis, mechanical vapor recompression,
aeration, and chemical addition. Table 3-3 lists the airports selected for EPA sampling, the
reason for selection, and the points that were sampled.
3.5 Permit Review
During the regulatory development process, EPA reviewed National Pollutant Discharge
Elimination System (NPDES) permits to understand what permit authorities are currently
requiring of airports with respect to deicing stormwater control. Using the data gathered during
the permit review assisted EPA in:
1. Assessing the current state of deicing stormwater control;
2. Evaluating the effectiveness of various deicing stormwater control measures; and
3. Identifying potential measures that EPA could use to further control deicing
stormwater.
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Section 3 - Data Collection Activities
Table 3-3. Airports Selected for Sampling and the Reason for Their Selection
Airport Name
Airport
Code
Dates of
Sampling
Reason for Sampling
Sample Points
Detroit Metropolitan
Wayne County
Detroit, MI
Episode 6508
DTW
3/31/05
Collects highly
concentrated ADF for
recycling, significant
stormwater volumes,
direct and indirect
discharger
Untreated deicing stormwater
Effluent from ADF-contaminated
stormwater collection pond
Effluent from pavement deicer
stormwater collection pond
ADF, as applied
Quality control (QC) samples 1
Minneapolis/St. Paul
International
Minneapolis/St. Paul,
MN
Episode 6509
MSP
4/28/05
On-site collection and
recycling facility, direct
and indirect discharger
High concentration ADF-
contaminated stormwater storage
tank
Low concentration ADF-
contaminated stormwater storage
tank
Influent to pavement deicer
stormwater collection pond
Effluent from pavement deicer
stormwater collection pond
ADF, as applied
QC samples 1
Albany International
Albany, NY
Episode 6523
ALB
2/5/06-
2/10/06
Reported recovery
efficiency of 72% of
applied ADF through
collection and treatment
(anaerobic and aerobic)
of ADF-contaminated
stormwater
Influent to anaerobic treatment
Effluent from anaerobic treatment
Effluent from aerobic treatment
QC samples 1
Pittsburgh
International
Pittsburgh, PA
Episode 6528
PIT
2/26/06-
3/3/06
Reported recovery
efficiency of 60-66% of
applied ADF through
collection and treatment
(ultrafiltration and
reverse osmosis (RO)) of
ADF -contaminated
stormwater
Influent to RO treatment
Effluent from RO treatment
QC samples 1
Denver International
Denver, CO
Episode 6522
DEN
3/26/06-
3/31/06
ADF -contaminated
stormwater collection
with glycol recovery
Influent to mechanical vapor
recompressions (MVRs)
Influent to distillation column
Distillate from MVRs
Overhead from distillation column
Effluent from treatment
QC samples 1
Greater Rockford
Rockford, IL
Episode 6529 and 6530
RFD
4/20/06
and
8/29/06
On-site aerated lagoon
treatment system (run in
batch mode) for its
deicing-contaminated
stormwater
SDrina Samoline
Influent to aerobic pond treatment
QC samples 1
Summer Sampling
Effluent from aerobic pond
treatment
QC samples 1
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Section 3 - Data Collection Activities
3.5.1 Airport Selection for Permit Review
For this review, EPA selected the top 50 U.S. airports based on ADF usage. At the time
of review, usage estimates from the airline survey were not available; therefore, EPA estimated
the airports with the highest usage using a "weighting factor" based on the number of snow or
freezing precipitation (SOFP) days and commercial departures as a measure of ADF usage.
Table 3-4 displays the results of the weighting factor analysis and lists the 50 airports for which
EPA reviewed permits.
3.5.2 Obtaining NPDES Permits
From the list of selected airports for permit review, EPA identified those for which it
already had permits. While airports were not required to submit permits as part of their
questionnaire response, some airports did so. Furthermore, there were some permits already
available in the airport deicing record files. Therefore, as a first step, EPA reviewed available
documentation and survey responses to identify in-house permit availability.
As a next step, EPA identified NPDES permit numbers for those permits not available in-
house. Some airports reported permit numbers in the airport questionnaire, so in these cases,
EPA obtained the data from the questionnaire database. For the remaining airports, EPA
searched its Envirofacts search tool by facility name, location, SIC code (4581), or a
combination of any of the three to obtain the permit numbers.
After identifying the permit numbers, EPA obtained a copy of the permit from a state or
regional permit database. If a permit was not available online, EPA contacted the appropriate
regional, state, or local permitting authority to obtain a copy. If still unsuccessful in obtaining the
permit, EPA contacted the airport directly to request a copy.
There were a few airports for which EPA could not identify permit numbers from either
the questionnaires or Envirofacts. For these airports, EPA searched the Internet or contacted
permitting authorities or the airports directly to obtain a copy of the permit.
3.5.3 Permit Review Process
The objectives of the permit review were to answer the following questions:
What are the monitoring requirements for deicing area outfalls?
What pollutants are monitored?
Are there numeric limits listed in the permit for deicing area outfalls?
What parameters are limited?
What are the limits for each parameter?
How were the limits developed?
Are there deicing operation best management practices (BMPs) required by the
permit?
What BMPs are required?
When does the permit expire?
If it is a general permit, are there differences between the permit and the EPA
Multi-Sector General Permit (MSGP)?
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Table 3-4. Top 50 Airports in the United States with the Highest ADF Usage, Estimated Based on SOFP Days and Total
Airport Departures
Rank
Airport
ID
Airport Code
Airport Name
State
SOFP Days
Total Airport
Departures
Weighting Factor
SOFP Days x
Departures
100,000
1
1006
ORD
Chicago O'Hare International
IL
26
467,721
121.6
2
1126
MSP
Minneapolis /St Paul International - Wold-
Chamberlain
MN
41
246,286
101.0
3
1138
DTW
Detroit Metropolitan Wayne County
MI
31
250,629
77.7
4
1028
DEN
Denver International
CO
26
264,051
68.7
5
1012
ANC
Ted Stevens Anchorage International
AK
55
88,126
48.5
6
1053
BOS
General Edward Lawrence Logan International
(Boston)
MA
26
186,253
48.4
7
1113
CVG
Cincinnati/Northern Kentucky International
KY
17
247,165
42.0
8
1069
CLE
Cleveland - Hopkins International
OH
36
116,569
42.0
9
1142
IAD
Washington Dulles International
DC
17
238,635
40.6
10
1107
PIT
Pittsburgh International
PA
31
125,143
38.8
11
1145
EWR
Newark Liberty International
NJ
16
203,082
32.5
12
1095
MDW
Chicago Midway International
IL
26
108,385
28.2
13
1139
PHL
Philadelphia International
PA
12
227,749
27.3
14
1136
MKE
General Mitchell International (Milwaukee)
WI
31
85,128
26.4
15
1029
LGA
La Guardia (New York City)
NY
12
192,127
23.1
16
1066
SLC
Salt Lake City International
UT
14
160,472
22.5
17
1010
FAI
Fairbanks International
AK
89
24,919
22.2
18
1011
STL
Lambert - St Louis International
MO
17
129,414
22.0
19
1148
MCI
Kansas City International
MO
27
76,016
20.5
20
1021
BUF
Buffalo Niagara International
NY
48
41,916
20.1
21
1089
JFK
John F Kennedy International (New York City)
NY
12
154,606
18.6
22
1024
IND
Indianapolis International
IN
21
83,769
17.6
23
1141
DCA
Ronald Reagan Washington National
DC
12
134,346
16.1
24
1129
BDL
Bradley International (Windsor Locks)
CT
31
51,389
15.9
25
1059
ROC
Greater Rochester International
NY
44
35,726
15.7
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Section 3 - Data Collection Activities
Table 3-4 (Continued)
Rank
Airport
ID
Airport Code
Airport Name
State
SOFP Days
Total Airport
Departures
Weighting Factor
SOFP Days x
Departures
100,000
26
1111
CMH
Port Columbus International
OH
26
59,938
15.6
27
1036
BWI
Baltimore - Washington International
MD
12
124,033
14.9
28
1026
DFW
Dallas/Fort Worth International
TX
4
360,933
14.4
29
1065
ALB
Albany International
NY
36
39,324
14.2
30
1080
SYR
Syracuse Hancock International
NY
44
30,840
13.6
31
1140
MEM
Memphis International
TN
8
166,910
13.4
32
1128
CLT
Charlotte/Douglas International
NC
6
214,396
12.9
33
1079
MHT
Manchester
NH
36
34,860
12.5
34
1058
GRR
Gerald R Ford International (Grand Rapids)
MI
48
25,015
12.0
35
1037
IAH
George Bush Intercontinental (Houston)
TX
4
248,339
9.9
36
1123
DAY
James M Cox Dayton International
OH
26
35,709
9.3
37
1020
ATL
Hartsfield - Jackson Atlanta International
GA
2
459,765
9.2
38
1121
PVD
Theodore Francis Green State (Providence)
RI
21
43,671
9.2
39
1147
RDU
Raleigh - Durham International
NC
10
86,302
8.6
40
1068
OMA
Eppley Airfield (Omaha)
NE
26
33,022
8.6
41
1105
GEG
Spokane International
WA
31
27,269
8.5
42
1108
SDF
Louisville International - Standiford Field
KY
12
65,586
7.9
43
1124
DSM
Des Moines International
IA
31
23,951
7.4
44
1074
SBN
South Bend Regional
IN
48
13,722
6.6
45
1153
CAK
Akron - Canton Regional
OH
41
14,911
6.1
46
1109
ILN
Airborne Airpark (Wilmington)
OH
21
25,508
5.4
47
1018
GSO
Piedmont Triad International (Greensboro)
NC
14
38,257
5.4
48
1100
TOL
Toledo Express
OH
36
14,385
5.2
49
1022
FWA
Fort Wayne International
IN
31
16,247
5.0
50
1051
HYA
Barnstable Municipal - Boardman/Polando Field
(Hyannis)
MA
26
18,782
4.9
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Technical Development Document for Effluent
Limitation Guidelines and Standards for the Airport Deicing Category
Section 3 - Data Collection Activities
EPA also consulted Envirofacts as necessary to fill in any numeric limit data gaps from
the permits and to cross-check for accuracy with the permitted limits.
To facilitate interpreting the results, EPA created a Microsoftฎ Access database to store
the data obtained from the reviews. The database consists of two tables: a General Information
table, and a Pollutant-Specific Information table. Table 3-5 and Table 3-6 detail the database
table descriptions. A summary of the permit review is presented in the memorandum Airport
Deicing Operations NPDES Permit Review Summary (ERG, 2007).
Table 3-5. Permit Review General Information Table
Data Element
Data Element Description
AirportID
The airport identification number used for the Airport Questionnaire
PermitID
The airport NPDES identification number
PermitExpiration
The permit expiration date
PermitBMPs
A checkbox that identifies the presence of BMPs in the permit
PermitBMPsDescription
A field that allows the BMPs in the permit to be listed
GeneralPermit
A checkbox that identifies general permits
GeneralPermitDifference
from MSGP
A field that describes any differences that exist between general permits and the
MSGP
PermitMonitoring
A checkbox that indicates if the permit requires monitoring
PermitLimits
A checkbox that indicates if the permit has numeric limits
PermitLimitRationale
A field that describes what rationale was used to determine the limits in the permit
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Section 3 - Data Collection Activities
Table 3-6. Permit Review Pollutant-Specific Information Table
Data Element
Data Element Deseription
AirportID
The airport identification number used for the detailed airport questionnaire.
PermitSamPoint
The outfall/sampling area identifying number.
PermitStreamDescription
The description of the outfall/sampling area. EPA tried to determine which outfalls
receive deicing stormwater and to include only information from those outfalls. If
the deicing outfalls cannot be determined, EPA included all outfalls.
PermitPollutant
The pollutants that are monitored and/or limited at each outfall, using the following
same codes that are used in the questionnaire database:
BOD Metal ORG (organic TSS
COD (chemical N (nitrogen) pollutants) Other
oxygen demand) OG (oil & pH
Fecal coliform grease) TOC (total
organic carbon)
OtherDesc
If a pollutant is monitored/limited that does not have a code, "Other" was selected
as the Permit Pollutant and the pollutant name was entered in this field. This
method of tracking pollutants was used to be consistent with the questionnaire
database.
PermitTimes
To be consistent with the questionnaire database, the frequency of monitoring for
each pollutant and outfall was recorded in the PermitTimes and PermitFreq fields.
These fields allow the frequency to be reported in a number/unit manner. For
example, a yearly report is entered as PermitTimes = 1 and PermitFreq = Year.
Frequency Codes were also used in the PermitFreq field for daily (D), monthly
(M), and quarterly (Q) reports.
PermitFreq
PermitLimitNumeric
The numeric value of the permit limit for each pollutant and outfall.
PermitLimitUnit
The unit of the permit limit for each pollutant and outfall.
LimitType
Indicates whether the limit is a minimum value, maximum value, average, or
simply a reporting requirement. This also incorporates the time span of the limit
using the frequency codes as above (e.g., daily maximum = DMAX; weekly
average = WAVG).
Season
For deicing outfalls, the limits may vary by season for various parameters. Usually,
this field is populated with Summer, Winter, or All (as in year-round).
3.6 Deicing Pad Costs
To evaluate the potential financial impacts of deicing pads for new airports, EPA
reviewed deicing pad cost information received from airports. EPA collected deicing pad costs
from Pittsburgh International airport and Minneapolis/St. Paul airport during the site visits, and
information was provided by Akron-Canton Regional airport via email on May 3, 2007, and
from Cleveland-Hopkins International airport as part of comments in its airport questionnaire
response.
3.7 Industry-Submitted Data
Based on airport site visits, EPA sampling episodes, and responses to the airport
questionnaire, EPA requested costing and long-term analytical data for managing deicing
stormwater from specific airports. The Agency used this information to develop control
technology options and compliance cost estimates, and to evaluate pollution prevention and best
management practices.
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Section 3 - Data Collection Activities
Table 3-7 and Table 3-8 list those airports providing data, the type of system used to
manage or treat the airport's deicing stormwater, and the costing and/or analytical data submitted
by the airport.
Table 3-7. Summary of Costing Data Provided by Industry
Airport
Tvpc of Deicing Stormwater
Management
Costing Data Provided
Akron-Canton Regional
Anaerobic ADF-contaminated
stormwater treatment system
Capital and operating and maintenance costs
for the airport's new anaerobic fluidized bed
(AFB) treatment system
Albany International
AFB/aerobic ADF-contaminated
stormwater treatment system
Capital and operating and maintenance costs
for the airport's AFB/aerobic treatment system
Cincinnati/Northern
Kentucky International
Glycol recovery and recycling
system
Capital and operating and maintenance costs
for glycol collection and treatment
Denver International
Storage, recovery, and recycling;
MVR and distillation system
Capital costs for storage and the
recycle/recovery system
General Mitchell
International
Recovery and recycling; anaerobic
digester
Engineering and monitoring-related costs
Minneapolis/St. Paul
International -Wold
Chamberlain
ADF collection (deicing pads, plug
and pump system)
Capital costs for deicing pads and operating
and maintenance costs for plug and pump
system
Pittsburgh International
ADF collection at deicing pads;
ADF-contaminated stormwater
recovery and recycling
Operating and maintenance costs for deicing
pads
Seattle-Tacoma International
ADF to industrial waste treatment
plant
Study costs for determining all known and
reasonable technology (AKART) for handling
aircraft deicing fluids
Table 3-8. Summary of Long-Term Analytical Data Provided by Industry
Airport
Type of Deicing Stormwater
Management
Long-Term Analytical Data
Provided
Albany International
Anaerobic/aerobic ADF-contaminated
stormwater treatment
Ammonia, COD
Denver International
Storage, recovery, and recycling;
MVR/distillation
COD
Detroit Metropolitan -
Wayne County
Recycling; distillation and recovery
Ammonia
Pittsburgh International
Ultrafiltration/Reverse Osmosis; ADF-
contaminated stormwater recovery and
recycling
Ammonia, urea
Salt Lake City International
ADF recovery and recycling
COD
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Technical Development Document for Effluent
Limitation Guidelines and Standards for the Airport Deicing Category
Section 3 - Data Collection Activities
3.8 Literature Reviews
EPA conducted preliminary literature searches during the effluent guideline development
process to supplement information acquired from site visits, sampling, and questionnaires. The
purpose for the literature searches was three-fold:
To collect information on current airport deicing practices and trends, and gather
information on state-of-the-art deicing stormwater treatment and/or glycol
recovery technologies;
To collect available data from airports currently monitoring wastewater
discharges; and
To obtain studies on the toxicity and environmental impact of current deicing
fluids and deicing discharges.
The following sections list the data sources used for each literature search.
3.8.1 Current Deicing Practices and Treatment Technologies
EPA performed keyword searches on three online search engines: 1) Cambridge
Scientific Abstracts (CSA); 2) Dialog Version 5.0; and 3) Google. CSA provides access to
over 50 databases published by CSA and its publishing partners, such as Aqualine,
Environmental Sciences & Pollution Management Database, and Water Resources Abstracts.
Dialog provides access to over 900 databases and handles more than 700,000 searches. The
databases in Dialog that contain articles pertaining to airport deicing are BIO SIS Toxicology,
Life Sciences Abstracts, Institute for Science Information, ProQuest Info & Learning, Ei
Compendex, Enviroline, TGG National Newspaper Index, GeoBase, National Technical
Information Service (NTIS), and Wilson Applied Science & Technology Abs.
The keywords for the literature searches included: airport deicing, aircraft, airfield,
runway, aircraft deicing, aircraft deicing fluid (ADF), runway deicing, anti-icing, anti-icing fluid,
airport stormwater, snow melt, centralized deicing pads, environmental assessment,
environmental impact study (EIS), fish mortality, fish kill, and publicly owned treatment works.
EPA also used other online journal databases, such as Science Direct, Scirus, and
Infotrak, for subject-specific articles. The treatment technologies featured in the articles found
included:
AFB reactor/ biological treatment;
Aerated storage tanks;
Anaerobic co-digestion of ADF and municipal wastewater sludge;
Batch-loaded AFB reactor;
Glycol reclamation/recycling and concentration;
Infrared technology;
Phytoremediation;
Plant-enhanced remediation;
Spray irrigation;
Subsurface-flow constructed wetlands; and
Surface detention ponds.
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Section 3 - Data Collection Activities
3.8.2 Current A irport Deicing Discharge Data
In addition to sampling and airport questionnaire data, EPA procured airport deicing
discharge information from its Permit Compliance System (PCS) database and online journals.
EPA downloaded all data reports from PCS for SIC code 4581: Airports, flying fields, and
services. Not all airports report this data to their permitting authority, so the scope of discharge
data is limited. The pollutant parameters include temperature, dissolved oxygen, BOD, TSS,
metals, fecal coliform, aromatic hydrocarbon, pH, and oil and grease. For online searches, EPA
procured journals that discussed deicing discharge containing ADF chemicals such as
benzotriazole, propylene/ethylene glycol, and alklyphenol ethoxylates. EPA also collected
monitoring data during the site visit to the Minneapolis/St. Paul International Airport.
3.8.3 Chemical Information and Environmental Impact Studies
The methodology and databases used for chemical information and environmental impact
study findings are similar to those used for the deicing practices and treatment technology
search. EPA conducted searches for the following categories:
Chemical Properties of ADF Ingredients: Physical appearance, structure,
solubility, reactivity;
Human Toxicity: Inhalation, ingestion, dermal effect, oral rat lethal dose (LD50)
values;
Aquatic Toxicity: Aquatic life lethal concentration (LC50) values; and
Chemical Fate and Transport: Soil sorption, fate in river, streams, and
estuaries, breakdown pathways in anaerobic and aerobic conditions, and
biodegradability.
In addition to journal articles, EPA gathered chemical information from Material Safety
Data Sheets (MSDSs), Chemfinder.com, the Pesticides Action Network (PAN) Pesticides
Database, and the U.S. Patents Database.
The keywords for the pollutant term search included: PG, PG-based fluids, EG, EG-based
fluids, urea, potassium acetate, calcium magnesium acetate (CMA), sodium acetate, sodium
formate, dissolved oxygen, biodegradation, BOD, and ADF additives (e.g., tolytriazole,
benzotriazole, nonylphenols, nonylphenol ethoxylate, etc.).
3.8.4 Current Deicing Discharge Regulations
In addition to the data sources described above, EPA searched the Internet using
Google to review regulatory documents that contain guidelines, operation controls,
management programs, laws, statutes, and certification requirements related to airport deicing
from the United States, Canada, Germany, Norway, and other European countries.
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Section 3 - Data Collection Activities
3.9 Data Collected Based on Public Comments
EPA collected and received limited additional information as part of the public comment
process. This section summarizes the information EPA collected as part of and in response to
public comments on the proposed rule and the types of data provided as part of the public
comments. Section 3.9.1 summarizes information that EPA collected to confirm deicing pad use
and operations at major airports and data collected to supplement the costing effort in response to
comment. Section 3.9.2 summarizes the types of data submitted as part of the public comments
to the proposed rule.
3.9.1 EPA-Collected Data
EPA received comments on the proposed regulation that airports that had previously
installed deicing pads did not use them for all flights that required deicing. EPA contacted the
following airports in early August 2010 to confirm information on the airport's deicing pad use
and operations:
Minneapolis/St. Paul International Airport (MSP);
Washington Dulles International Airport (IAD);
Philadelphia International Airport (PHL);
Detroit Metropolitan/Wayne County Airport (DTW);
Denver International Airport (DEN);
Cleveland-Hopkins International Airport (CLE);
Salt Lake City International Airport (SLC); and
Pittsburgh International Airport (PIT).
Table 3-9 summarizes the information collected for these airports.
EPA also collected additional post-proposal information as part of revisions to the costing
analysis in response to specific public comments. Additional costing information collected by
EPA included drainage cover data that it used in conjunction with existing cost data for Glycol
Collection Vehicles (GCVs). The supplemental data collected to inform GCV costing is
summarized in a memorandum entitled Estimated Capital and Operation and Maintenance Costs
for Glycol Collection Vehicle Operation (ERG, 2010a). EPA also collected vendor data related
to liquid application and storage of airfield deicing chemicals. These data are summarized in the
memorandum entitled Estimated Costs for Transition to Liquid Airfield Deicing Application
from Solid Airfield Deicing (ERG, 2010b). In addition, Section 10 presents the liquid application
and storage of airfield deicing chemical cost data used in developing the final rule cost analysis.
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Section 3 - Data Collection Activities
Table 3-9. Selected Airport Information Related to Deicing Pad Operations
Airport
Deicing Pad Operations Data
Minneapolis/St. Paul
International Airport
1. MSP encourages the use of deicing pads and requires deicing in contained
locations only. ADF stormwater is contained through deicing pad use (and its
collection system), block and pump, and cover and sweep (using glycol collection
vehicles). There are no exceptions to the requirement for contained locations for
deicing operations.
2. MSP estimates that 65-70% of ADF fluid used at the airport is sprayed at its
deicing pads. The percentage of flights represented by this amount of ADF fluid use
is much lower than 65-70%. The deicing pads are typically used for heavy deicing
and not for defrost deicing. Delta, previously Northwest Airlines, deices at both the
gate and at the deicing pads. Overall, they spray more deicing fluid at the pads than
at the gates. This airline does not generally act as an FBO for other airlines but may
be used as a deicing provider in a backup situation. The small airlines operating at
the airport do not have personnel for deicing pad use.
3. If deicing is not done on the deicing pads, it is done at the gate.
4. Advantages of the MSP deicing pads include putting the deiced aircraft closer to
the runway, which lowers the chance of missing ADF holdover times, and freeing
up the gates for incoming flights.
Washington Dulles
International Airport
1. Approximately 50% of the flights deiced at IAD are deiced on deicing pads. In
addition, the airport requires that flights be deiced in areas of capture that may
include glycol collection vehicles.
2. There are no specific requirements on where each airline has to deice their
planes. The location of where each airline plans to deice is decided between the
airlines at winter "snow meetings."
Philadelphia International
Airport
1. All commercial aircraft except commuter aircraft (regional jets and turbo-props)
must be deiced at the airport deicing pad, as specified in the airport's NPDES
permit.
2. Aircraft defrosting is permitted at the gates with a usage limit of 20-40 gallons of
ADF, as specified in the airport's NPDES permit.
3. Deicing of the plane is also permitted at the gate with no ADF usage limit, for
required weight reduction or visibility enhancement, sufficient to safely taxi the
aircraft to the deicing pad for final, pre-take-off ADF application.
Detroit
Metropolitan/Wayne
County Airport
1. DTW does not have a specific requirement forcing the airlines to deice aircraft at
the deicing pads but does strongly encourage deicing pad use.
2. The airport estimates that approximately 90% of the airport traffic that is deiced
uses the deicing pads.
3. The airport allows 747s to deice at the gates to free up the deicing pads for
smaller aircraft. Airport study of this allowance shows that it achieves a higher net
capture of ADF using this approach. The airport collects ADF stormwater from the
747 deicing using a glycol collection vehicle in conjunction with catch basin
inserts.
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Section 3 - Data Collection Activities
Table 3-9 (Continued)
Airport
Deicing Pad Operations Data
Denver International
Airport
1. DEN does not allow full-plane gate deicing, and does not track limited gate
deicing operations specifically (other than to enforce the 25-gallon rule discussed in
item 3. below). The airport tracks only the volume of fluid used on an airport-wide
basis but estimates that 95% of deicing occurs on the dedicated deicing pads. DEN's
largest carrier, United Airlines (UAL), does provide DEN (Environmental Services)
with its fluid usage data, including by location. UAL's data show approximately 6%
of its total fluid used was applied at the gates pursuant to DEN's 25-gallon
operational allowance. UAL's data do not provide the number of flights deiced by
location. On average, UAL accounts for approximately 27% of the total aircraft
deicing fluid applied at DEN.
2. DEN is not aware of any specific instances of deicing outside the designated
areas (pads, gates (limited), GA, South Cargo). If it did occur, it would be a very
rare occurrence under special circumstances, and would require prior approval from
the Manager of Aviation.
3. Limited deicing requirements are stipulated on page 6 of DEN Rule and
Regulation Part 190 - Aircraft Deicing Regulations. The language does not specify
for what purpose limited deicing may occur, only that "In no event may the total
amount of deicing fluid used in a limited deicing exceed 25 gallons neat (undiluted)
ADF per aircraft." DEN R&R Part 190 can be accessed directly at
http://business.flydenver.com/info/research/rules/index.htm.
4. On a volume-only basis, for the 2008/2009 season, DEN data show
approximately 5% of the total amount of deicing fluid used at DEN was applied at
South Cargo and General Aviation (combined).
Cleveland-Hopkins
International Airport
1. CLE estimates that 90% of deiced flights are deiced at deicing pads and the
remaining 10% are deiced at the gate. Most of the air carriers are not allowed to
deice at the concourse gates.
2. For those air carriers not allowed to deice at the gate, the airport does allow
emergency deicing to unfreeze the wheels or other plane parts to allow the plane to
move safely to the deicing pad.
Salt Lake City
International Airport
1. At SLC, 95-98% of the deiced flights are deiced on pads and each major airline
has its own dedicated deicing pad.
2. All deicing is to occur on the deicing pads except for specific circumstances that
are typically delay related.
Pittsburgh International
Airport
1. Aircraft deicing at the airport is required by consent decree to occur on deicing
pads. Thus, 100% of deiced flights are deiced on the airport's pads unless doing so
will result in a total loss of operations (e.g., major delays or if the deicing pad is out
of ADF). The airport does allow gate deicing for both defrost and safety purposes.
2. PIT defines defrost deicing as "the removal of contamination (frost) from critical
components of the airport that occurs when there is no active precipitation" and
defines regular deicing as "the removal of contamination (snow/ice) that occurs
when there is or has been active precipitation."
3. When an air carrier conducts gate deicing (instead of using the deicing pads), it
must document why the deicing occurred at the gate.
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Section 3 - Data Collection Activities
3.9.2 Data Submitted with Public Comments
All comments received on the proposed airport deicing rulemaking are available in the
docket. In assessing comments, EPA evaluated, and in some cases used, data or suggestions
provided by specific commenters for the final rule analyses. While the data submitted by
commenters were useful, in general, commenters provided very little analytical data on treatment
or collection performance. Commenters, however, did provide some new data related to the
costing analysis and on the feasibility of deicing pads. Section 10 summarizes the data used to
develop EPA's final rule costs. As an example, EPA incorporated industry-supplied data on AFB
capital costs versus COD loading in its final costing analysis (see Figure 10-1).
Comments by specific airports/port authorities on the proposed rule, including Boston-
Logan International Airport and The Port of New York and New Jersey, included documentation
supporting a claim that their airports are space-constrained and they would not be able to locate a
deicing pad facility to comply with the proposed rule. EPA considered this data in developing the
final rule and is no longer requiring collection of spent ADF at existing airports.
3.10 References
ERG. 2007. Memorandum from Jason Huckaby (ERG) to Brian D'Amico and Eric Strassler
(U.S. EPA). Airport Deicing Operations NPDESPermit Review Summary. (April 16). DCN
AD00611.
ERG. 2010a. Memorandum from Steve Strackbein and Mary Willett (ERG) to the Airport
Deicing Administrative Record. Estimated Capital and Operation and Maintenance Costs for
Glycol Collection Vehicle Operation. (October 8). DCN AD01249.
ERG. 2010b. Memorandum from Steve Strackbein and Mary Willett (ERG) to Brian D'Amico
and Eric Strassler (U.S. EPA). Estimated Costs for Transition to Liquid Airfield Deicing
Application from Solid Airfield Deicing. (October 8). DCN AD01252.
USEPA. 2000. Preliminary Data Summary: Airport Deicing Operations. U.S. Environmental
Protection Agency. Washington, D.C. EPA-821-R-00-016. Available online at
http://www.epa.gov/guide/airport. DCN AD00005.
USEPA. 2005. Supporting Statement: Survey of Airport Deicing Operations. U.S. Environmental
Protection Agency. Washington, D.C. DCN AD00447.
USEPA.2008a. Airline Screener Questionnaire Database. U.S. Environmental Protection
Agency. Washington, D.C. DCN AD00937.
USEPA. 2008b. Airline Detailed Questionnaire Database. U.S. Environmental Protection
Agency. Washington, D.C. DCN AD00938.
USEPA. 2008c. Airport Questionnaire Database. U.S. Environmental Protection Agency.
Washington, D.C. DCN AD00927.
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Section 4 - Overview of the Industry
4. Overview of the Industry
This section provides an overview of the airport deicing/anti-icing performed by selected
airports and airlines. The overview includes statistics on the number and location of airports and
airlines that perform deicing/anti-icing (Section 4.1) and deicing and anti-icing practices
performed on airfields and aircraft and methods used to collect and control deicing stormwater
(Section 4.2).
4.1 Industry Statistics
Data sources for statistics on the number and types of airports and airlines include
responses to EPA's airport and airline questionnaires, the Bureau of Transportation Statistics,
FAA, and EPA's Preliminary Data Summary: Airport Deicing Operations (PDS) (USEPA,
2000). Data provided in responses to EPA questionnaires are based on deicing/anti-icing
operations performed during the winter seasons of 2002/2003, 2003/2004, and 2004/2005,
hereafter referred to as the three winter seasons.
4.1.1 Airports
The North American Industry Classification System (NAICS) identification number
applicable to airport deicing is 488119: Other Airport Operations. The U.S. Census Bureau
describes this industry as establishments primarily engaged in the following: (1) operating
international, national, or civil airports or public flying fields, or (2) supporting airport
operations, such as runway maintenance services, hangar rental, and/or cargo handling services.
The airport questionnaire data presented in this section are based on the 150 respondents
to EPA's airport questionnaire. EPA applied weighting factors to the information provided by
selected airport questionnaire recipients to scale up the questionnaire data to represent national
estimates.
4.1.1.1 Number and Types of Airports
FAA's general categories of airports include commercial, general aviation, and relievers.
Commercial airports are public airports receiving scheduled passenger service and having more
than 2,500 enplaned passengers (number of passengers boarding a plane for departure) each year.
General aviation airports have less than 2,500 enplanements per year or do not receive scheduled
commercial service. Relievers are high-capacity general aviation airports in major metropolitan
areas, and provide an alternative for small aircraft using busy commercial airports.
Airports may be further classified into several different categories, depending on the size
and activity level of the airport. Often both of these factors can be determined by the number of
enplanements or operations (number of arrivals and departures) at the airport in a given year.
FAA classifies large commercial airports into "hubs," based on the number of annual
enplanements that occur at the airport. Large Hubs are defined as airports with more than 1
percent of total U.S. passenger enplanements. Medium Hubs are defined as airports with more
than 0.25 percent but less than 1 percent of total passenger enplanements. Small Hubs account
for 0.05 to 0.25 percent of the total passenger enplanements. Airports with less than 0.05 percent
of the total passenger enplanements but more than 10,000 annual enplanements are considered
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Section 4 - Overview of the Industry
Non-hub primary airports. Nonprimary commercial services are those airports that have 2,500 to
10,000 enplanements a year.
According to FAA 2004 data and the FAA's National Plan of Integrated Airport Systems
(NPIAS) Report to Congress, about 3,344 airports operated in the United States in 2004. Table
4-1 identifies the number of airports by type as defined by number of enplanements. For all
airport types, excluding general aviation airports, the totals in Table 4-1 represent counts for
January through December 2004. FAA's designation of hub status depends on the percentage of
total passenger boardings occurring at each airport, causing the number of airports in each hub
category to vary from year to year.
Table 4-1. Number of U.S. Airports by Airport Type in 2004
Airport Type
Number of Airports
Large Hub
33
Medium Hub
36
Small Hub
67
Non-hub
231
Other Nonprimary
130
General Aviation1
2,573
General Aviation Relievers 1
274
TOTAL
3,344
General aviation and general aviation reliever airports (open to the public) from the NPIAS Report to Congress
(USDOT, 2008a).
Note: Airport counts will differ depending on the source and year of data represented.
EPA distributed the airport questionnaire to 153 airports that included, based on 2004
information, all Large Hub, all Medium Hub, and a statistical sampling of Small Hub and Non-
hub airports, as well as judgment sampling of some general aviation/cargo, and other nonprimary
airports. EPA determined that one airport recipient was out of scope and removed it from the
sample frame. EPA received responses from 150 of these airports. Using the airport responses
and their statistical weights and including the cargo airports and Alaskan airport judgment
samples, EPA estimated that the number of primary commercial airports nationally that perform
deicing and/or anti-icing of airfield pavement and/or aircraft is 334.
4.1.1.2 Geographic Location of Deicing Airports
The location of the airport and its climate have a direct impact on deicing operations.
Airport deicing/anti-icing operations occurred in 44 states in the three winter seasons. As shown
below, the FAA divides the United States into the following nine regions:
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Section 4 - Overview of the Industry
Region
State
Alaskan
AK
Central
IA, KS, MO
Eastern
DE, MD, NJ, NY, PA, VA, WV
Great Lakes
IL, IN, MI, MN, ND, OH, SD, WI
New England
CT, ME, MA, NH, RI, VT
Northwest Mountain
CO, ID, MT, OR, UT, WA, WY
Southern
AL, FL, GA, KY, MS, NC, PR, TN, VI
Southwest
AR, LA, NM, OK, TX
Western-Pacific
AZ, CA, HI, NV, GU, AS, MH
Source: FAA, "FAA Regional Offices," http://www.faa.gov/about/office_org/headquarters_offices/arp/
regional offices/ (U.S. DOT, 2008b).
Table 4-2 summarizes the regions for the airports that reported deicing in the EPA airport
questionnaire for the three winter seasons surveyed by EPA. (Note: these are not national
estimates.) The Great Lakes and Eastern regions reported the highest number of deicing airports.
Table 4-2. Deicing Airports by FAA Region for the Three Winter Seasons
Region
Airports Reporting Deicing and/or Anti-Icing in EPA
Airport Questionnaire
Great Lakes
31
Eastern
22
Southern
20
Northwest Mountain
17
Western-Pacific
15
Southwest
14
Alaskan
10
New England
6
Central
5
Source: EPA airport questionnaire database (USEPA, 2008c).
4.1.1.3 Weather Impacts on Airport Deicing/Anti-Icing
Airports conduct deicing/anti-icing operations when weather conditions, such as
precipitation and/or temperature, have the potential to cause icing. Precipitation includes
snowfall, rainfall, sleet (including freezing rain), and ice. The type of precipitation affects the
volume and type of deicing/anti-icing chemicals used on aircraft and airfield pavement. For
example, freezing rain requires the most deicing/anti-icing agent usage because the rain freezes
on contact and coats the aircraft or airfield pavement to form a solid layer of ice. Dry-weather
deicing, performed when the ambient temperature is cold enough to form ice on aircraft wings
and surfaces (below 55ฐ F), generally requires only a small volume of ADF.
The duration of the deicing/anti-icing season is also determined by the climate at an
airport location. Airfield pavement deicing can begin as early as September and continue through
May in colder climates and/or areas with high numbers of snow or freezing precipitation days.
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The national estimate of airports performing airfield pavement deicing is 215; this is lower than
the national estimate of airports performing deicing operations overall because there are airports
that have some aircraft deicing (usually defrost deicing) but no airfield pavement deicing. In
general, these airports are located in warm and/or dry weather climates with minimal winter
storm events. For months when airfield pavement deicing occurs, December, January, and
February have the most occurrences of airfield pavement deicing, and September and May have
the lowest. Figure 4-1 presents the percentage of these 215 airports deicing airfield pavement for
each month. The time frame during which an airport conducts deicing during a typical winter
season ranges from two to nine months, and a majority of airports typically conduct deicing/anti-
icing operations for five months a season. For the three winter seasons surveyed by EPA, the
average reported number of airfield pavement deicing days among these 215 airports ranges
from 0.3 to 240 days.
80%
70%
60%
50%
at
a>
ns
at
a.
30%
20%
10%
0%
71%
69%
61%
27%
5% 5%
0% 0% 0%
24%
55%
71ฐ
^ ^ ^ ^ .<& ^
^ ^ ,^v ^
Month
Figure 4-1. Percentage of Airports Deicing Airfield Pavement Each Month
4.1.1.4 Destination of Airport Deicing Stormwater
Airport questionnaire respondents reported direct, indirect, and zero discharge of deicing
stormwater. Direct dischargers discharge deicing stormwater directly to U.S. surface waters,
such as creeks, rivers, ponds, lakes, or oceans. Indirect dischargers convey deicing stormwater by
pipe, conduit, or hauling to a publicly owned or other treatment works. A zero discharger
disposes of deicing stormwater using methods other than direct or indirect discharge. Figure 4-2
presents the reported discharge status of airports by destination. Scaling the questionnaire data to
a national estimate results in 176 airports discharging to surface water only, 52 airports
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discharging both directly to surface water and indirectly to a POTW, 10 airports discharging to a
POTW only, and 96 airports reporting zero discharge.
Zero Discharge
29%
Direct Discharge
Only
52%
Indirect
Discharge Only
3%
Direct and
Indirect
Discharge
16%
Figure 4-2. Discharge Status of Airports
A majority of the zero dischargers reported conducting aircraft deicing only (i.e., no
deicing of airfield pavement). These airports generally are in warm and/or dry weather climates
and have minimal dry weather (defrost) deicing. Airports reported various methods for
maintaining zero discharge that included evaporation, storage in surface impoundments, contract
hauling, and recycle/recovery of deicing stormwater. The most common zero discharge method
reported was evaporation followed by discharge to a surface impoundment and the "other"
category. The methods identified as "other" zero discharge techniques included, infiltration,
discharge to tundra over permafrost, use of drain covers and sorbent material, and use of BMPs.
Even though over 100 airports indicated that they do not have any direct discharge (96
zero discharge and 10 POTW only) of ADF-contaminated stormwater, EPA believes that
fugitive ADF emissions from overspray and tracking and dripping, during taxiing and takeoff,
are difficult if not impossible to track and will likely result in direct discharges, albeit potentially
small ones.
4.1.2 Airlines
The NAICS code for airlines is 481: Air Transportation. Specific NAICS codes for
respondents to the airline deicing questionnaires are: (1) 481111: Scheduled Passenger Air
Transportation, described by the U. S. Census Bureau as establishments primarily engaged in
providing air transportation of passengers or passengers and freight over regular routes and on
regular schedules; and (2) 481112: Scheduled Freight Air Transportation, described by the U.S.
Census Bureau as establishments primarily engaged in providing air transportation of cargo
without transporting passengers over regular routes and on regular schedules.
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The airline data presented in this section are based on the 49 respondents to EPA's airline
detailed questionnaire and additional information from the 70 respondents to EPA's airline
screener questionnaire. Statistics for airlines do not have weighting factors and are based on the
actual number of respondents.
4.1.2.1 Types of Airlines
The four classifications of airlines are major, national, regional, and cargo and are based
on the type of service they offer and their annual revenues. Classification is based on the
economic and financial aspects of each airline's aircraft fleet. Table 4-3 lists the criteria for the
four classifications.
Table 4-3. Airline Classifications
Airline Type
Annual Revenues
Type of Service
Aircraft Fleet
Major
>$100 million
Regular schedules
Large jets: >60 seats
Payload >18,000 lbs
National
$100 million to $1 billion
Regular schedules
Medium and large jets
Regional:
Large
Medium
Small
(commuters)
$20 million to $100 million
<$20 million
No revenue cut-off
Limited to single U.S. region
Scheduled
Scheduled
Scheduled
>60 seats
Lesser or greater than 60 seats
<30 seats
Cargo
No revenue cut-off
Scheduled
Passenger aircraft with seats
removed
Source: Preliminary Data Summary: Airport Deicing Operations (Revised) (USEPA, 2000).
There were 20 major airlines in the United States in 2006. Many national airlines
typically serve multiple U.S. regions whereas regional airlines are generally limited to a single
region of the country.
Small regional airlines are the largest segment of the regional airline business. Regional
airlines may be private business carriers, commercial airlines, charter airlines, or provide a
combination of these services. Private business carriers represent about 60 percent of regional
airline flights. Regional airlines serve all airports served by major airlines as well as smaller
airports that are not served by any major airline. They typically operate out of one gate area
unless they are affiliates of major airlines and operate at the gates of their affiliate. Regional
airlines conduct a disproportionately large number of flight operations per passenger because
their aircraft are smaller and carry fewer passengers per operation.
All respondents to the airline detailed questionnaire reported conducting deicing/anti-
icing operations on their aircraft at a total of 57 airport locations.
4.1.2.2 Types of Airline/Airport Relationships
The relationship between airports and airlines regarding deicing operations is one of
dependency and cooperation. Airports and airlines conduct deicing using chemical and
nonchemical methods in the same airfield locations and both contribute pollutants to deicing
stormwater. Airlines may conduct deicing on their own aircraft, deicing for other airlines, and/or
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may also use FBOs. An airline's deicing methods must be approved by the FAA for air safety.
Airports provide the collection and control systems to contain and/or treat deicing stormwater
generated as a result of aircraft and airfield deicing. However, both airports and airlines
implement pollution prevention practices such as evaluating application rates, using alternate
chemicals, pretreating pavement and aircraft, and manually removing snow and ice to reduce the
quantity of pollutants discharged and the amount of deicing stormwater generated.
4.2 Industry Practices
Airport deicing and anti-icing operations involve chemical and mechanical methods and
are conducted at varied locations and by different entities. This section discusses these practices
and pollution prevention methods used by airports and airlines as reported by respondents to the
airport and airline deicing questionnaires.
4.2.1 Airfield Deicing Practices
Airfield pavement deicing/anti-icing removes or prevents the accumulation of frost,
snow, or ice on runways, taxiways, aprons, gates, and ramps. These methods are typically
conducted by airport personnel, FBOs, or private contractors using a combination of mechanical
methods and chemical deicing/anti-icing agents. To reduce the quantity of pollutants or the
amount of deicing stormwater generated, airports also use various pollution prevention measures.
Responses to EPA's airport questionnaire indicated that 67 percent of airports have the
primary responsibility for airfield pavement deicing/anti-icing.
4.2.1.1 Chemical Deicing/Anti-Icing
The type of precipitation and temperature affect the volume and type of deicing agents
required for deicing/anti-icing. Common pavement deicing/anti-icing agents used at airports
include potassium acetate, sand, airside urea, sodium acetate, glycol-based fluids, and sodium
formate, as reported by respondents to EPA's airport questionnaire. Potassium acetate and PG-
based fluids were reported as the top deicing/anti-icing chemicals (by weight) used on airfield
pavement during the three winter seasons surveyed by EPA; some respondents also reported
using a mixture of these agents as well as heated sand. Table 4-4 provides national estimates of
the number of airports using these agents. Airports purchase primarily ready-to-apply rather than
concentrated formulations of these chemicals. See Section 6.1 for a detailed discussion of
deicing chemical usage.
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Table 4-4. National Estimate of Airports Using Deicing Chemicals or Materials
Dcieing/Anti-Icing
Chemical or
Material
Number of Airports Using Deicing Chemical/Material
Average
Percentage of
Airports Using
Deicing Chemical/
Material
2002/2003
2003/2004
2004/2005
Potassium Acetate
94
104
111
103
31
Sand
103
104
98
102
30
Airside Urea
58
60
59
59
17
Sodium Acetate
39
34
33
35
10
PG-Based Fluids
16
16
16
16
5
Sodium Formate
22
1
23
15
5
EG-Based Fluids
6
6
6
6
2
Source: EPA airport questionnaire responses (scaled to national estimates) (USEPA, 2008c).
4.2.1.2 Mechanical and Nonchemical Deicing/Anti-Icing
Mechanical methods, such as plows, brushes, blowers, and shovels for snow removal, are
the primary forms of airfield pavement deicing and may be used in combination with chemical
methods. One facility uses heated pavement through pavement temperature sensors to prevent
airfield pavement from icing. All of the 215 airports that conduct pavement deicing use some
form of chemical, while an estimated 212 (99 percent) use mechanical methods as well on
airfield pavement.
4.2.2 Aircraft Deicing Practices
Aircraft deicing involves removing frost, snow, or ice from aircraft. Aircraft anti-icing
entails preventing frost, snow, or ice from accumulating on aircraft surfaces. Both chemical and
nonchemical deicing/anti-icing methods are conducted on aircraft at varied airport locations and
by different entities. The FAA also influences aircraft deicing, as it has approval authority for the
deicing/anti-icing practices and procedures selected. Airlines and FBOs also perform pollution
prevention practices similar to airports to reduce the quantity of pollutants discharged and/or
reduce the amount of deicing stormwater generated.
Aircraft deicing may be conducted by an airline, FBO, or private contractor. Often, larger
airline carriers deice their own aircraft and possibly the aircraft of other airlines. In addition, the
entity conducting aircraft deicing for an airline may vary depending on the airport location. All
of the airline questionnaire respondents reported deicing their own aircraft at one or more of their
airport locations. Airline respondents also reported FBOs and/or another airline deiced their
aircraft (84 percent and 56 percent, respectively) at some of their airport locations.
Aircraft deicing is conducted at a variety of airport locations and may be conducted at
multiple types of locations at the same airport. Aircraft deicing is most commonly performed at
deicing pads and terminal gates and apron areas. Airline respondents reported aircraft deicing at
the following locations (the percentage of the airline respondents reporting using the specific
type of location is in pararentheses):
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Deicing pad (80 percent);
Passenger terminal gates/apron areas (78 percent);
Aircraft parking aprons (46 percent);
Airfield ramps (42 percent);
Taxiways (24 percent);
Cargo apron areas (16 percent); and
Other locations (12 percent) (e.g., hangar).
4.2.2.1 Chemical Deicing/Anti-Icing
The type of precipitation and temperature influences the volume and type of deicing
chemicals required to deice/anti-ice aircraft. Two types of aircraft deicing are conducted: wet-
weather and dry-weather. Wet-weather deicing is conducted when snow, sleet, or freezing rain
accumulates on the aircraft. Dry-weather deicing is conducted when frost or ice forms on the
aircraft due to changes in the ambient temperature or when fuel tanks become cooled during
high-altitude flight, forming ice at lower altitudes and after landing. Dry-weather deicing
requires significantly smaller volumes of ADFs than wet-weather deicing.
Aircraft deicing/anti-icing chemicals are categorized into four classes: Type I, Type II,
Type III, and Type IV. Not all types are currently used. Airlines surveyed by EPA reported
consistently using only Type I and Type IV fluids. ADFs vary by composition and allowable
holdover times (i.e., the amount of time the residual fluid protects aircraft from ice formation).
They generally contain either EG or PG, water, and additives to remove or prevent ice and snow.
Type I ADF is used to remove ice and snow that has accumulated on aircraft, and Type IV fluids
are used for anti-icing to increase holdover times for an aircraft prior to takeoff. Deicing fluids
are usually heated prior to application, while anti-icing fluids are typically applied at ambient
temperatures.
All fluids are usually applied under pressure using a nozzle, often from mobile deicing
trucks (as reported by 31 airlines). Below are additional types of ADF application equipment
used, as reported in responses to the airline questionnaire:
Other equipment (e.g., brooms, ground sprayer and ladder, palletized equipment
and fork lift, towed tower, small portable unit, self-contained mobile unit);
Fixed booms; and
Handheld bottle/containers.
Table 4-5 identifies the types of ADF fluids purchased by airlines that deiced their own
aircraft during the three winter seasons, as well as the average across those seasons, based on the
49 airline respondents to the airline detailed questionnaire. Table 4-6 lists the ADF fluids
purchased by an FBO during the three winter seasons and the average across those seasons, as
reported in the airline questionnaire. As shown in the tables, Type I and Type IV PG are the most
commonly purchased ADF fluids for deicing aircraft, both by airlines that deice their own
aircraft and airlines that use FBOs.
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Table 4-5. Deicing/Anti-Icing Chemicals Purchased by Airlines that Deiced Their Own
Aircraft
Number of Ai
Nines Purchasing
I Chemicals
Average Number of
Dcicing/Anti-Icing
Chemical
2002/2003
2003/2004
2004/2005
Airlines Purchasing
Chemicals
Type IPG
29
29
28
29
Type IV PG
22
22
23
22
Type I EG
8
8
8
8
Type IV EG
6
5
4
5
Type II PG
0
0
1
1
Source: EPA airline detailed questionnaire database (USEPA, 2008b).
Table 4-6. Deicing/Anti-Icing Chemicals Purchased for Aircraft Deiced by an FBO
Deicing/Anti-Icing
Chemical
Number of Airlines for Chemicals Purchased by an
FBO
Average Number of
Airlines for Chemicals
2002/2003
2003/2004
2004/2005
Purchased by an FBO
Type I PG
35
36
39
37
Type IV PG
31
35
37
34
Type I EG
17
13
13
14
Type IV EG
13
9
9
10
Type II PG
0
2
1
1
Type II EG
0
0
1
1
Source: EPA airline detailed questionnaire database (USEPA, 2008b).
4.2.2.2 Mechanical and Nonchemical Deicing/Anti-Icing
Mechanical and other nonchemical methods used to deice aircraft include brooms, ropes,
hot water, infrared heating, and forced air. Brooms and ropes are not the primary method of
aircraft deicing, especially wet-weather deicing, because they are so time- and labor-intensive,
but rather are used in combination with chemical deicing. Forced air/hot air systems are used to
blow or melt snow and ice from aircraft surfaces. Infrared heating deicing systems consist of an
open hangar-type structure with infrared generators suspended from the ceiling. The infrared
wavelengths are targeted to heat ice and snow and minimize heating of aircraft components. This
system reduces the volume of ADF fluid required, but cannot provide anti-icing protection.
Aircraft may also be stored in a hangar to prevent snow or ice from accumulating if a storm
event is predicted. The most common mechanical and nonchemical methods of deicing/anti-icing
used by airline questionnaire respondents are mechanical methods and hangar storage. Table 4-7
and Table 4-8 summarize the use of these methods for deicing/anti-icing aircraft by airlines and
by FBOs, respectively.
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Table 4-7. Summary of Mechanical and Nonchemical Aircraft Deicing Methods Used by an
Airline
Mcehanieal/Nonchemical
Method
Number of Airlines
Average Number
of Airlines
2003/2004
2003/2004
2004/2005
Mechanical (e.g., brooms, ropes)
22
21
21
21
Hangar storage
15
16
16
16
Forced air
9
7
7
8
Hot water
5
4
4
4
Infrared heating
1
1
1
1
Source: EPA airline detailed questionnaire database (USEPA, 2008b).
Table 4-8. Summary of Mechanical and Nonchemical Aircraft Deicing Methods Used By
FBOs
Mcehanieal/Nonchemical
Method
Number of Airlines
Average Number
of Airlines
2003/2004
2003/2004
2004/2005
Mechanical (e.g., brooms, ropes)
10
10
10
10
Hangar storage
5
5
5
5
Forced air
4
5
5
5
Hot water
3
4
4
4
Infrared heating
0
0
0
0
Source: EPA airline detailed questionnaire database (USEPA, 2008b).
4.2.3 Airport Deicing Stormwater Collection and Control
Deicing and anti-icing operations are conducted at multiple locations at an airport, and
the fluids are widely dispersed during and after application via ramp discharge, taxiway
drippage, and residual on aircraft. Deicing stormwater is contained and collected using
designated deicing areas, stormwater drainage systems, glycol recovery, storage tanks,
containment ponds, and plug and pump systems. Typical sources of deicing stormwater are:
Terminal gates and aprons/areas;
Aircraft deicing pads;
Taxiway s;
Airfield ramps;
Runways;
Cargo apron areas;
Maintenance hangar ramps;
Aircraft parking areas;
Military bases; and
ADF-contaminated snow dumps.
Table 4-9 summarizes the collection and control methods used by airports. Based on
responses to the airport questionnaire, an estimated 246 U.S. airports use containment,
collection, and/or conveyance measures to control the discharge of deicing stormwaters to
surface waters and/or POTWs. Most of the airports use stormwater drainage systems and
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containment ponds and basins. See Section 9.0 for detailed discussions of deicing stormwater
collection and control methods used by the Airport Deicing Category.
Table 4-9. Summary of Airport Collection, Containment, and Conveyance Methods
Collcction/Containmcnt/Convcyancc Method
Estimated Number
of Airports
Percentage of
Airports
Stormwater drainage system
211
63
Containment pond/basin
121
36
Aboveground/underground tank
57
17
Glycol collection vehicles/sweepers
54
16
Other (vegetated swales, snow melters, absorbant)
34
10
Plug and pump
29
9
Source: EPA airport questionnaire database (scaled to national estimate) (USEPA, 2008c).
EPA estimates that approximately half (46 percent) of the U.S. airports with deicing
operations also operate systems to treat or recover their deicing stormwater. The treatment and
recovery technologies reported by airports include equalization (46 percent), oil/water separation
(5 percent), sand or other media filtration (4 percent), membrane separation (1 percent), and
biological treatment (1 percent). Eight percent of the airports report using other types of
treatment technologies, including MVR, aeration, and distillation. Section 7 describes these
technologies in detail.
4.2.4 Pollution Prevention Practices
To reduce the quantity of pollutants discharged and the amount of deicing stormwater
generated, airports implement various pollution prevention practices that control pollution from
airport deicing chemicals (e.g., glycol), thus minimizing pollutant loads by reducing chemical
usage. Physical snow removal, specialized employee training, and pretreatment of airfields in
advance of precipitation are the most common practices used by airports for airfield pollution
prevention. The national estimate of airports implementing one or more pollution prevention
practices is 244. Table 4-10 summarizes EPA's national estimates of the number and percentage
of airports that used airfield pollution prevention practices. See Section 7.4 for detailed
descriptions of the pollution prevention practices used by airports.
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Table 4-10. Summary of Airfield Pollution Prevention Practices
Pollution Prevention Praeticc
Estimated Number of
Airports Using Practice
Percentage of Airports
Using Practice
Specialized employee training
153
46
Pretreatment of airfield in advance of precipitation
101
30
Runway ice detection system
95
28
Enhanced weather forecasting
77
23
Heated sand
74
22
Evaluation of application rates of deicing fluids
56
17
Use of alternative chemicals
40
12
Use of prewet dry chemical constituents
32
10
Other
88
26
Source: EPA airport questionnaire database (scaled to national estimates) (USEPA, 2000c).
Airlines also implement pollution prevention practices at various airports. These practices
control pollution from aircraft deicing chemicals and minimize pollutant loads. Specialized
training, implementation of a pollution prevention policy, and physical snow removal are the
most common pollution prevention practices used by airlines. Table 4-11 summarizes airline
pollution prevention practices reported in response to the airline detailed questionnaire. See
Section 7.4 for detailed descriptions of the pollution prevention practices used by airlines.
Table 4-11. Summary of Aircraft Pollution Prevention Practices
Pollution Prevention Practice
Number of Airlines Reporting Practice
Specialized employee training
43
Instituting pollution prevention policy
43
Physical removal of snow or freezing precipitation
31
Overnight pretreatment/storage of aircraft
30
Custom fluid blending
27
Enhanced weather forecasting
25
Evaluation of application rates of deicing fluids
24
Pretreating aircraft with hot water
9
Use of alternative chemicals
2
Other
30
Source: EPA airline detailed questionnaire database (USEPA, 2008b).
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4.3 References
USDOT. 2008a. Report to Congress: National Plan of Integrated Airport Systems (NPIAS)
2009-2013. U.S. Department of Transportation, Federal Aviation Administration. Washington,
D.C. Available online at
http://www.faa.gov/airports_airtraffic/airports/planning_capacity/npias/reports/.
USDOT. 2008b. FAA Regional Offices. U.S. Department of Transportation, Federal Aviation
Administration. Washington, D.C. Available on line at
www.faa.gov/about/office_org/headquarters_offices/arp/regional_offices/.
USEPA. 2000. Preliminary Data Summary: Airport Deicing Operations. U.S. Environmental
Protection Agency. Washington, D.C. EPA-821-R-00-016. DCN AD00005. Available online at
http://www.epa.gov/guide/airport.
USEPA. 2005. Supporting Statement: Survey of Airport Deicing Operations. U.S. Environmental
Protection Agency/Office of Water. Washington, D.C. DCN AD00447.
USEPA. 2008a. Airline Screener Deicing Questionnaire Database. U.S. Environmental
Protection Agency. Washington, D.C. DCN AD00937.
USEPA. 2008b. Airline Detailed Deicing Questionnaire Database. U.S. Environmental
Protection Agency. Washington, D.C. DCN AD00938.
USEPA. 2008c. Airport Deicing Questionnaire Database. U.S. Environmental Protection
Agency. Washington, D.C. DCN AD00927.
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Section 5 - Deicing Chemical Use and Deicing Stormwater Characterization
5. Deicing Chemical Use and Deicing Stormwater Characterization
This section summarizes EPA's estimate of the amount of airfield and aircraft
deicing/anti-icing chemicals currently in use by U.S. primary commercial airports and provides
information on deicing stormwater pollutant characteristics to the extent possible. Deicing
stormwater discharges are "weather-dependent" and they are, by nature, highly variable. In
addition, deicing chemical disposition after its intended use is not fully understood. These
chemicals may be lost to evaporation, dispersion, or soil absorption; collected; or released into
the environment and discharged from the airport, but limited information is currently available
on each of these disposition methods. This section presents the information EPA has collected on
the types of pollutants present in deicing stormwater and their ranges of concentrations.
5.1 Deicing Chemical Usage
As discussed in Section 4, several deicing chemicals are commonly used at U.S.
commercial airports. These chemicals are used for either airfield or aircraft deicing/anti-icing
and their usages are described below.
5.1.1 Airfield Chemical Use
Pavement deicing/anti-icing removes or prevents frost, snow, or ice from accumulating
on runways, taxiways, aprons, gates, and ramps. Airports use mechanical and chemical methods
for this purpose. The more often-used method is mechanical removal, but because ice, sleet, and
snow may be difficult to remove by mechanical methods alone, many airports also use sand
and/or chemical deicing agents such as potassium acetate, sodium acetate, sodium formate,
glycol-based products, or urea. Based on the data collected by EPA in the airport questionnaire,
the most common airfield deicing chemical currently used by U.S. airports is potassium acetate
(approximately 63 percent of airfield chemical usage by weight). Section 9, Table 9-6 presents
the average amount of pavement deicing chemical usage in pounds per year by airport and by
deicing chemical.
Table 5-1 lists the total estimated national average airfield chemical usage (based on data
for the 2002/2003, 2003/2004, and 2004/2005 deicing seasons) for primary commercial airports
in the United States.
Table 5-1. U.S. Commercial Airports - National Estimate of Airfield Chemical Usage
Chemical
Estimated Total Airport Usage
(tons/year)
Percentage of
Chemical Usage
Potassium acetate
22,538
63
Propylene glycol-based fluids
3,883
11
Airside urea
4,127
12
Sodium acetate
3,100
9
Sodium formate
1,117
3
Ethylene glycol-based fluids
774
2
Source: EPA Airport Deicing Questionnaire Database (USEPA, 2008a)
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5.1.2 Aircraft Chemical Use and Purchasing Patterns
There are four types of ADFs manufactured around the world, referred to by the aviation
and chemical industries as Types I through IV. Of these, Type I and Type IV are commonly used
at U.S. commercial airports. Type I ADF is used to defrost and deice aircraft and Type IV ADF
is used to prevent icing from recurring (anti-icing) after initial deicing with a Type I ADF. ADFs
contain a primary freezing point depressant (typically PG or EG) and other additives. ADFs
work by adhering to aircraft surfaces to remove and/or prevent snow and ice accumulation by
virtue of their depressed freezing points. Airports conduct two types of deicing: dry-weather
deicing to remove frost and wet-weather deicing and anti-icing during precipitation such as
snow, sleet (ice pellets), or freezing rain. Airports may also perform dry-weather deicing on
some types of aircraft whose fuel tanks become super-cooled during high-altitude flight,
allowingfrost/ice to form on aircraft wings at lower altitudes and after landing. Based on the data
collected by EPA in the airline detailed questionnaire, the most common ADF is Type IPG-
based fluids (approximately 77 percent of ADF usage). In addition, U.S. airports have been
trending towards using more PG-based fluids and less EG-based fluids. Table 9-3 in Section 9
presents EPA's estimates of ADF annual usage by airport based on the airline questionnaire
responses and the estimation procedure outlined in that section.
Table 5-2 presents a national estimate of the average aircraft chemical usage by U.S.
commercial airports by type of fluid.
Table 5-2. U.S. Commercial Airports - National Estimate of Aircraft Chemical Usage 1
Chemical
Average Total Airport Usage
(million gallons/year)2
Percentage of Chemical Usage
Type I PG ADF
19.305
77.1
Type IV PG ADF
2.856
11.4
Type I EG ADF
2.575
10.3
Type IV EG ADF
0.306
1.2
Sources: EPA Detailed Airline Questionnaire (USEPA, 2008b); Airport Deicing Loadings Database (USEPA,
2008c).
1 EPA used the ADF purchase information to represent usage, per airline industry recommendations.
2 Total gallons normalized to 100% PG/EG.
5.2 Deicing Stormwater Characterization
EPA evaluated data from a variety of sources to better understand the components of
deicing chemicals and ADFs that collect in deicing stormwater. These data include:
Information on the additives included in ADFs;
Data collected during sampling of concentrated and diluted ADFs used at the
Detroit Metropolitan Wayne County (DTW) and Minneapolis/St. Paul
International (MSP) airports during the 2003/2004 deicing season;
Data collected during sampling of deicing stormwater at the Albany International
(ALB), Pittsburgh International (PIT), Denver International (DEN), and Greater
Rockford (RFD) airports during the 2004/2005 deicing season;
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Technical Development Document for Effluent
Limitation Guidelines and Standards for the Airport Deicing Category
Section 5 - Deicing Chemical Use and Deicing Stormwater Characterization
Current data for airports included in the PCS database; and
Deicing stormwater data collected by EPA during the PDS, through site visits, or
through industry or permit authority submissions.
Section 6 summarizes the types of pollutants found in deicing stormwater based on these
sources.
5.2.1 Airfield Deicing Chemicals and Associated Deicing Stormwater
Most solid airfield deicing chemical products comprise a freezing point depressant (e.g.,
potassium acetate, sodium acetate) and minimal additives (e.g., corrosion inhibitors). Liquid
airfield deicing chemical products comprise a freezing point depressant (e.g., potassium acetate,
PG), water, and minimal additives. The airfield deicing products that include salts (i.e.,
potassium acetate, sodium acetate, and sodium formate) will ionize in water, creating positive
salt ions (K+, Na+) and BOD load as the acetate or formate ion degrades into carbon dioxide
(C02) and water.
Urea is typically applied to pavement and runway areas in granular form. Urea degrades
by hydrolysis to C02 and ammonia, which can be toxic to aquatic organisms even at very low
concentrations. Once ammonia is formed, it either remains in solution as ammonia or its ionized
form (NH4+), biologically converts to other nitrogen forms (e.g., N03 or N2), or volatilizes to the
air. The formation of ammonia is dependent on the pH and temperature of the receiving water.
The higher the pH and temperature, the more ammonia is formed. Another potentially toxic by-
product of urea degradation is nitrous acid, which reacts with secondary amines to form
nitrosamines, many of which are known carcinogens.
EPA has limited data on airfield deicing stormwater alone (i.e., stormwater that does not
also contain aircraft deicing area stormwater). Most of EPA's stormwater data include both
airfield and aircraft deicing components. However, during sampling at DTW, EPA collected
samples from the airport's runway and open area ponds (Pond 3 East and Pond 6). These ponds
are not expected to contain aircraft deicing stormwater because a separate pond collects
wastewater from the gate and deicing pad areas where the stormwater is expected to contain
ADF. DTW sometimes uses sand and potassium acetate for runway traction and deicing in
addition to their usual mechanical snow removal equipment. It does not use urea-based deicers.
Table 5-3 presents the sampling data from the two airfield/open area runoff ponds.
5.2.2 Aircraft Deicing Chemicals and Associated Deicing Stormwater
ADFs primarily comprise a freezing point depressant (typically PG or EG), additives, and
water. Typical additives are thickening agents, wetting agents, corrosion inhibitors, buffer, and
dye, which make up 1 to 4 percent of the fluid mass. Type IV fluids have higher concentrations
of the freezing point depressant and greater viscosity so that the fluid stays on the aircraft until
take-off.
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Technical Development Document for Effluent
Limitation Guidelines and Standards for the Airport Deicing Category
Section 5 - Deicing Chemical Use and Deicing Stormwater Characterization
Table 5-3. EPA's Analytical Results for Pond 3E Effluent and Pond 6 Effluent, DTW
Analyte
Unit
Pond 3 East Effluent
Pond 6 Effluent
bod5
mg/L
146
43.0
Chloride
mg/L
855
315
COD
mg/L
273
111
Nitrate/Nitrite (N02 + N03-N)
mg/L
0.0400
0.110
Sulfate
mg/L
50.1
51.0
Total Dissolved Solids (TDS)
mg/L
1,790
833
Total Kjeldahl Nitrogen (TKN)
mg/L
1.51
0.990
TOC
mg/L
813
314
Total Phosphorus
mg/L
0.340
0.280
TSS
mg/L
150
149
Aluminum
(ig/L
1,660
2,110
Aluminum, Dissolved
(ig/L
ND (50.0)
64.5
Barium
(ig/L
92.3
81.8
Barium, Dissolved
Hg/L
77.5
66.5
Calcium
(ig/L
96,600
69,400
Calcium, Dissolved
(ig/L
91,000
63,500
Chromium1
M-g/L
ND (10.0)
ND (10.0)
Copper1
Hg/L
ND (10.0)
ND (10.0)
Iron
M-g/L
3,630
4,390
Iron, Dissolved
M-g/L
407
600
Magnesium
Mg/L
20,300
17,400
Magnesium, Dissolved
Mg/L
18,200
15,700
Manganese
Mg/L
508
411
Manganese, Dissolved
Mg/L
462
335
Molybdenum
Mg/L
ND (10.0)
ND (10.0)
Molybdenum, Dissolved
Mg/L
ND (10.0)
ND (10.0)
Sodium
Mg/L
547,000
191,000
Sodium, Dissolved
Mg/L
522,000
189,000
Titanium
Mg/L
26.2
34.8
Zinc 1
Mg/L
41.4
43.8
Acetone
Mg/L
ND (50.0)
ND (50.0)
PG -16712
mg/L
ND (10.0)
ND (10.0)
PG - 8015D 2
mg/L
ND (10.0)
ND (10.0)
Source: Final Sampling Episode Report Detroit Metropolitan Wayne County International Airport (DTW) (USEPA,
2006a).
1 Pollutant listed by EPA as a priority pollutant. See 40 CFR Part 423, Appendix A.
2 Number following analyte name refers to analytical method. 1671 is a Clean Water Act method and 8015D is a
hazardous waste method promulgated under the Resource Conservation and Recovery Act (RCRA).
ND - Not detected (number in parentheses is reporting limit).
45
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Technical Development Document for Effluent
Limitation Guidelines and Standards for the Airport Deicing Category
Section 5 - Deicing Chemical Use and Deicing Stormwater Characterization
The actual composition of ADFs varies and information on specific additive compounds
is usually considered proprietary by ADF manufacturers. EPA believes that typical ADFs most
likely include the following components:
ADF Component
Composition (%)
PG or EG
50-88
Surfactant/wetting agent
About 0.5
Corrosion inhibitor/flame retardant
About 0.5
pH buffer
About 0.25
Dyes
<1
Water
Remainder
Source: Environmental Impact and Benefit Assessment for Proposed Effluent Limitations Guidelines and Standards
for the Airport Deicing Category (ERG, 2009).
Despite limited public information, EPA has identified two main classes of additives
widely used among ADF manufacturers. Alkylphenol/alkylphenol ethoxylates (AP/APEO) are
nonionic surfactants used to reduce surface tension in aircraft deicers and triethanolamine is used
as a pH buffer. (ERG, 2009). At the time of proposal of the rule, EPA also identified methyl-
substituted benzotriazole (MeBT) as an ADF additive, which was used as a corrosion
inhibitor/flame retardant. In conversations with ADF manufacturers since proposal, EPA has
been told that the use of triazole compounds in ADF is being discontinued and that triazole use
in European ADFs has been phased out. EPA also has information indicating that high molecular
weight, nonlinear polymers may be used as thickening agents in ADFs {see Aircraft Deicing
Fluids (ERG, 2007b) and various classes of dyes can be used to color the ADF. The classes of
dyes identified as potentially used in ADFs include azo, xanthene, triphenyl methane, and
anthroquinone dyes (see Questions Regarding Pylam Dye Use in ADF (ERG, 2007a).
Analyses conducted by the USGS at General Mitchell International (MKE) airport in
Milwaukee, WI, and EPA's sampling programs have confirmed the presence of glycols, triazole
compounds, and alkylphenol compounds in deicing stormwater. EPA collected deicing
stormwater samples at MSP and DTW during the 2004/2005 winter season. At MSP, EPA
collected samples of deicing stormwater from segregated high concentration and low
concentration storage tanks. At DTW, Northwest collected its deicing stormwater from a March
24, 2005 deicing event into a portable "frac" tank, which was then sampled by EPA. Table 5-4
lists the constituents detected in these deicing stormwaters and their concentrations. During the
2005/2006 deicing season, EPA collected five consecutive days of samples of influent to and
effluent from deicing stormwater treatment at ALB, PIT, DEN, and RFD. The sampled deicing
stormwater at these airports, prior to treatment, shows a wide range of constituents and
constituent concentrations among the airports, as shown in Table 5-5 and Table 5-6.
46
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Technical Development Document for Effluent
Limitation Guidelines and Standards for the Airport Deicing Category
Section 5 - Deicing Chemical Use and Deicing Stormwater Characterization
Table 5-4. MSP and DTW Grab Sample Data Summary for Collected Deicing Stormwater
Analytc
Unit
MSP
High
Concentration
Storage Tank
MSP
Low
Concentration
Storage Tank
DTW
Northwest Frac
Tank
Classical Pollutants
Ammonia as Nitrogen (NH3-N)
mg/L
ND (0.05)
ND (0.05)
0.790
BOD5
mg/L
115,000
8,000
140,000
Chloride
mg/L
45.0
27.0
25.0
COD
mg/L
358,000
16,000
332,000
Hexane Extractable Material (HEM)
mg/L
50.0
ND (5.00)
22.0
Nitrate/Nitrite (N02 + NO3-N)
mg/L
0.0950
<0.0600
0.240
Silica Gel Treated HEM (SGT-HEM)
mg/L
17.0
ND (5.00)
ND (6.00)
Sulfate
mg/L
21.2
13.6
20.3
TDS
mg/L
1,370
559
1,440
TKN
mg/L
13.5
5.61
71.1
TOC
mg/L
96,100
5,660
93,100
Total Phosphorus
mg/L
6.49
<2.10
0.320
Total Recoverable Phenolics
mg/L
0.150
0.0375
<0.007
TSS
mg/L
89.0
19.5
11.5
Total and Dissolved Metals
Aluminum
(ig/L
525
508
ND (500)
Aluminum, Dissolved
(ig/L
ND (500)
136
ND (500)
Antimony, Dissolved1
(ig/L
201
ND (20.0)
ND (200)
Barium
Hg/L
114
67.1
52.4
Barium, Dissolved
(ig/L
36.4
61.9
46.9
Calcium
(ig/L
68,200
35,200
127,000
Calcium, Dissolved
(ig/L
59,600
34,500
125,000
Copper1
(ig/L
ND (100)
37.6
ND (100)
Copper, Dissolved 1
Hg/L
ND (100)
16.4
ND (100)
Iron
(ig/L
11,000
7,470
1,410
Iron, Dissolved
(ig/L
4,960
6,030
1,370
Magnesium
(ig/L
9,230
4,250
12,900
Magnesium, Dissolved
Hg/L
8,490
4,080
13,000
Manganese
(ig/L
887
317
433
Manganese, Dissolved
(ig/L
756
308
423
Mercury 1
(ig/L
ND (40)
ND (2)
45.1
Mercury, Dissolved 1
(ig/L
ND (40)
ND (2)
68.7
Molybdenum
Hg/L
19,100
794
15,900
Molybdenum, Dissolved
(ig/L
19,000
771
16,000
Sodium
(ig/L
48,700
18,700
22,800
Sodium, Dissolved
(ig/L
48,100
18,600
19,200
Tin
Hg/L
611
32.1
673
47
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Technical Development Document for Effluent
Limitation Guidelines and Standards for the Airport Deicing Category
Section 5 - Deicing Chemical Use and Deicing Stormwater Characterization
Table 5-4 (Continued)
Analyte
Unit
MSP
High
Concentration
Storage Tank
MSP
Low
Concentration
Storage Tank
DTW
Northwest Frac
Tank
Tin, Dissolved
(ig/L
616
32.5
646
Titanium
(ig/L
ND (100)
13.5
ND (100)
Zinc 1
(ig/L
492
291
119
Zinc, Dissolved 1
(ig/L
444
277
119
Volatile and Semivolatile Organics
Acetone
(ig/L
1,440
23,700
3,340
PG- 16712
mg/L
192,000
PG - 8015D 2
mg/L
193,000
8,600
170,000
Trichloroethene 1
Hg/L
ND (10)
ND (10)
14.5
Sources: Final Sampling Episode Report Minneapolis/St. Paul International Airport (MSP) (USEPA, 2006b); Final
Sampling Episode Report Detroit Metropolitan Wayne County International Airport (DTW) (USEPA, 2006a).
1 Pollutant listed by EPA as a priority pollutant. See 40 CFR Part 423, Appendix A.
2 Number following analyte name refers to analytical method. 1671 is a Clean Water Act method and 8015D is a
hazardous waste method promulgated under the Resource Conservation and Recovery Act (RCRA).
< - Average result includes at least one nondetect value.
ND - Not detected (number in parenthesis is reporting limit).
48
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Technical Development Document for Effluent
Limitation Guidelines and Standards for the Airport Deicing Category
Section 5 - Deicing Chemical Use and Deicing Stormwater Characterization
Table 5-5. DEN, PIT, and ALB - 5-Day Average Data Summary for Untreated Deicing
Stormwater
Analyte
Units
DEN Effluent from
Equalisation Feed Tank
5-dav Average
PIT Influent to
Reverse Osmosis
(RO) Unit
5-day Average
ALB Influent to
Anaerobic Treatment
System
5-day Average
Alkalinity
mg/L
706
481
159
NH3-N)
mg/L
0.448
ND (0.05)
<0.262
bod5
mg/L
149,000
16,600
3,400
COD
mg/L
247,000
28,300
5,350
Chloride
mg/L
120
11.6
90.0
Hardness
mg/L
362
542
248
HEM
mg/L
9.20
ND (6.0)
ND (5.0)
NO3-N + NO2-N)
mg/L
0.0266
<0.0204
<0.0284
Sulfate
mg/L
60.0
48.1
26.4
TDS
mg/L
NC
1,670
650
TKN
mg/L
6.41
9.04
1.61
TOC
mg/L
89,000
7,720
1,570
Total Orthophosphate
mg/L
<1.03
<0.0196
0.115
Total Phosphorus
mg/L
<2.76
0.0778
0.946
Total Recoverable Phenolics
mg/L
0.0608
0.0187
ND (0.005)
TSS
mg/L
<17.8
<8.40
16.6
Arsenic
(ig/L
<81.8
12.7
ND (10)
Barium
(ig/L
<13.2
103
42.5
Boron
(ig/L
<723
532
ND (100)
Calcium
(ig/L
103,000
155,000
48,300
Copper
Mg/L
305
ND (10)
ND (10)
Iron
(ig/L
1,210
5,870
6,270
Magnesium
(ig/L
5,360
6,260
9,990
Manganese
(ig/L
156
532
736
Molybdenum
Mg/L
11,900
ND (10)
ND (10)
Selenium
(ig/L
172
31.8
<5.38
Sodium
|ig/L
254,000
54,300
89,600
Tin
|ig/L
<258
41.0
ND (30)
Zinc
|ig/L
<81.1
71.8
48.3
Acetone
|ig/L
4,100
10,900
15,400
Benzoic Acid
|ig/L
716
ND (50)
278
Methyl Ethyl Ketone
M-g/L
ND (50)
ND (50)
<58.5
Phenol
|ig/L
ND (100)
ND (100)
24.5
EG -16711
mg/L
<167
<65.6
ND (10)
EG - 8015D1
mg/L
<172
<73.6
ND (10)
49
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Technical Development Document for Effluent
Limitation Guidelines and Standards for the Airport Deicing Category
Section 5 - Deicing Chemical Use and Deicing Stormwater Characterization
Table 5-5 (Continued)
Analvte
Units
DEN Effluent from
Equalization Feed Tank
5-dav Average
PIT Influent to
Reverse Osmosis
(RO) Unit
5-day Average
ALB Influent to
Anaerobic Treatment
System
5-day Average
PG -16711
mg/L
174,000
15,700
2,570
PG - 8015D1
mg/L
173,000
15,900
2,630
Tolyltriazole
(ig/L
10,100
7,860
325
Nonylphenol, total
(ig/L
ND (5.0)
22.2
ND (12.0)
Nony lphenol-1 -Ethoxy late
(ig/L
ND (7.4)
130
ND (19.0)
Nonylphenol-2-Ethoxylate
(ig/L
ND (21.0)
190
ND (53.0)
Nony lphenol-3 -Ethoxy late
(ig/L
17.8
59.9
3.90
Nonylphenol-4-Ethoxylate
(ig/L
16.4
15.4
3.01
Nony lphenol-5 -Ethoxy late
(ig/L
21.5
213
5.70
Nonylphenol-6-Ethoxylate
(ig/L
50.4
403
12.5
Nony lphenol-7 -Ethoxy late
(ig/L
60.7
619
15.4
Nonylphenol-8-Ethoxylate
(ig/L
86.2
841
24.7
Nonylphenol-9-Ethoxylate
(ig/L
79.1
942
24.7
Nonylphenol-10-Ethoxy late
(ig/L
92.5
1,050
38.1
Nonylphenol-11 -Ethoxy late
(ig/L
100
1,040
40.4
Nonylphenol-12-Ethoxy late
(ig/L
216
833
33.7
Nonylphenol-13 -Ethoxy late
(ig/L
167
589
25.2
Nonylphenol-14-Ethoxy late
|ig/L
116
386
17.8
Nonylphenol-15 -Ethoxy late
(ig/L
69.9
222
8.80
Nonylphenol-16-Ethoxy late
|ig/L
43.4
107
4.69
Nonylphenol-17 -Ethoxy late
(ig/L
23.3
53.5
2.27
Nonylphenol-18-Ethoxylate
|ig/L
12.4
23.3
1.09
Octy lphenol
(ig/L
<8.80
ND (0.01)
ND (2.00)
Octylphenol-2-Ethoxy late
|ig/L
71.8
ND (0.144)
0.159
Octy lphenol-3 -Ethoxy late
(ig/L
1,460
4.38
2.66
Octy lphenol-4-Ethoxy late
Mg/L
1,260
ND (2.26)
ND (2.26)
Octy lphenol-5-Ethoxy late
Hg/L
891
ND (2.93)
ND (2.93)
Octy lphenol-6-Ethoxy late
Hg/L
441
ND (2.69)
ND (2.69)
Octy lphenol-7-Ethoxy late
Hg/L
198
ND (2.58)
ND (2.58)
Octy lphenol-8-Ethoxy late
Hg/L
116
ND (1.85)
ND (1.85)
Octy lphenol-9-Ethoxy late
Hg/L
44.6
ND (0.636)
ND (0.636)
Octy lphenol-10-Ethoxy late
Hg/L
22.5
ND (0.636)
ND (0.636)
Octy lphenol-11 -Ethoxy late
Hg/L
12.0
ND (0.267)
ND (0.267)
Octy lphenol-12-Ethoxy late
Hg/L
8.08
ND (0.113)
ND (0.113)
50
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Technical Development Document for Effluent
Limitation Guidelines and Standards for the Airport Deicing Category
Section 5 - Deicing Chemical Use and Deicing Stormwater Characterization
Table 5-5 (Continued)
Analvtc
Units
DEN Effluent from
Equalization Feed Tank
5-dav Average
PIT Influent to
Reverse Osmosis
(RO) Unit
5-day Average
ALB Influent to
Anaerobic Treatment
System
5-day Average
Total Nonylphenol-3-
Ethoxy late-Nonlyphenol-18-
(ig/L
1,170
7,400
260
Total Octylphenol-2-Ethoxylate-
Octy lphenol-12-Ethoxy late
Mg/L
4,530
ND (16.0)
ND (16.0)
Sources: Draft Sampling Episode Report Denver International Airport (USEPA, 2006c); Draft Sampling Episode
Report Pittsburgh International Airport (USEPA, 2006d); Draft Sampling Episode Report Albany International
Airport (USEPA, 2006e).
1 Number following analyte name refers to analytical method. 1671 is a Clean Water Act method and 8015D is a
hazardous waste method promulgated under the Resource Conservation and Recovery Act (RCRA).
ND - Not detected (number in parentheses is reporting limit).
NC - Not collected.
< - Average result includes at least one nondetect value.
51
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Technical Development Document for Effluent
Limitation Guidelines and Standards for the Airport Deicing Category
Section 5 - Deicing Chemical Use and Deicing Stormwater Characterization
Table 5-6. RFD - 1-Day Data Summary for Untreated Deicing Stormwater
Analvtc
Units
Influent to Aerobic Treatment
System, Spring
Alkalinity
mg/L
1,030
nh3-n
mg/L
59.6
bod5
mg/L
603
COD
mg/L
646
Chloride
mg/L
14.0
Hardness
mg/L
112
N03-N + NO2-N)
mg/L
0.0190
Sulfate
mg/L
5.65
TDS
mg/L
384
TKN
mg/L
82.8
TOC
mg/L
137
Total Phosphorus
mg/L
0.330
TSS
mg/L
85.0
Barium
Hg/L
20.3
Calcium
(ig/L
6,600
Iron
(ig/L
108
Magnesium
(ig/L
14,700
Manganese
Hg/L
164
Sodium
(ig/L
4,790
Acetone
(ig/L
86.6
Methyl Ethyl Ketone
(ig/L
136
PG - 8015D1
mg/L
31.0
Tolyltriazole
Hg/L
45.3
Bisphenol A
ng/L
ND (12,000)
N-Nonylphenol-2-Ethoxylate
NC
50.0
N-Nonylphenoxyl-2-Carboxylic Acid
NC
41.0
Octylphenol-9-Ethoxylate
Hg/L
ND (3.18)
Source: Final Sampling Episode Report Greater Rockford Airport (USEPA, 2006f)
1 Number following analyte name refers to analytical method. 8015D is a hazardous waste method promulgated
under the Resource Conservation and Recovery Act (RCRA).
ND - Not detected (number in parentheses is reporting limit).
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Technical Development Document for Effluent
Limitation Guidelines and Standards for the Airport Deicing Category
Section 5 - Deicing Chemical Use and Deicing Stormwater Characterization
5.3 Aircraft and Airfield Deicing Chemical Use and Associated Deicing
Stormwater at Alaskan Airports
Deicing operations at Alaskan airports may be different than those commonly seen at
other U.S. airports due to the nature of air travel in Alaska and weather conditions. In Alaska,
small airports have a relatively high number of commercial aircraft departures (including jet
aircraft) for the suite of communities they serve due to their remote locations with no access to
the road system. Yet these airports utilize small amounts of ADF and runway deicers because of
climate conditions (dry and cold), as well as runway maintenance scheduling. For example, in
Kotzebue, a town of 3,120 people, there are about 12,000 annual departures (including passenger
and freight jet planes and prop planes) and the fluid usage is only about 1,000 gallons/winter.
In addition, long periods of below-freezing temperatures affect the the timing of deicing
stormwater discharges. Deicing materials are not available for collection during freezing
temperatures because they are encapsulated within the snow and eventually become runoff
during the spring thaw. Thus, the stormwater runoff is not linked to the time of the ADF
application. For example, at locations in arctic Alaska such as Bethel Airport (BET), there is no
stormwater to collect during the deicing season (October - March) as temperatures rarely, if
ever, go above freezing. For these airports, collection strategies may be significantly different
than airports located within the lower 48 states. One current practice reported by Ted Stevens
Anchorage International Airport (ANC) is gas-and-go cargo operations, which involves anti-
icing on landing during certain weather conditions. This allows the airport to avoid deicing prior
to departure. This anti-icing procedure also uses less glycol and allows a quicker turnaround.
Due to the remote nature of Alaskan airports and aircraft scheduling, runways are
generally prepped for individual flights each day rather than maintaining continuous operation
around the clock. Because of this, Alaskan airports rely heavily on mechanical methods for
runway deicing. When airfield deicing chemical use is necessary, most airports in Alaska use
potassium acetate or urea.
5.4 References
Corsi, S.R., et al. 2003. NonylphenolEthoxylates and Other Additives in Aircraft Deicers, Anti-
icers, and Waters Receiving Airport Runoff. (January 1). DCN AD00083.
ERG. 2007a. Personal communication (telecony between Mary Willett (ERG) and Bob Reynolds
(Pylam Dyes). Questions Regarding Pylam Dye Use in ADF. (April 16). DCN AD00686.
ERG. 2007b. Personal communication (telecon) between Mary Willett (ERG) and Jeffery Carey
(Noveon). Aircraft Deicing Fluids. (April 16). DCN AD00688.
USEPA. 2006a. Final Sampling Episode Report Detroit Metropolitan Wayne County
International Airport (DTW), Episode 6508. U.S. Environmental Protection Agency.
Washington, D.C. (July 12). DCN AD00620.
USEPA. 2006b. Final Sampling Episode Report Minneapolis/St. Paul International Airport
(MSP), Episode 6509. U.S. Environmental Protection Agency. Washington, D.C. (July 12). DCN
AD00622.
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Section 5 - Deicing Chemical Use and Deicing Stormwater Characterization
USEPA. 2006c. Final Sampling Episode Report Denver International Airport, Episode 6522.
U.S. Environmental Protection Agency. Washington, D.C. (August 2). DCN AD00840.
USEPA. 2006d. Final Sampling Episode Report Pittsburgh International Airport, Episode 6528.
U.S. Environmental Protection Agency. Washington, D.C. (November 1). DCN AD00841.
USEPA. 2006e. Final Sampling Episode Report Albany International Airport, Episode 6523.
U.S. Environmental Protection Agency. Washington, D.C. (July 19). DCN AD00842.
USEPA. 2006f. Final Sampling Episode Report Greater Rockford Airport, Sampling Episode
6529 (April 20, 2006) and Sampling Episode 6530 (August 29, 2006, January 18, 2008). U.S.
Environmental Protection Agency. Washington, D.C. DCN AD00839.
USEPA. 2008a. Airport Deicing Questionnaire Database. U.S. Environmental Protection
Agency. Washington, D.C. DCN AD00927.
USEPA. 2008b. Airline Questionnaire Database. U.S. Environmental Protection Agency.
Washington, D.C. DCN AD00938.
USEPA. 2008c. Airport Deicing Loadings Database. U.S. Environmental Protection Agency.
Washington, D.C. DCN AD00857.
USEPA. 2009. Environmental Impact and Benefit Assessment for Proposed Effluent Limitation
Guidelines and Standards for the Airport Deicing Category. (July 1). EPA 821-R-09-005. DCN
AD01197.
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Section 6 - Pollutants of Concern
6. Pollutants of Concern
EPA identified pollutants in stormwater associated with deicing activities for potential
control. Pollutants of concern may include pollutants directly associated with deicing chemicals,
by-products from deicing activities (e.g., metals), and/or pollutant parameters that are influenced
by deicing chemicals (e.g., BOD and COD).
EPA reviewed its deicing stormwater sampling data as well as the information available
through NPDES permits to identify conventional, nonconventional, and priority pollutants
present in airport deicing stormwater. This section presents the results of EPA's evaluation and
identifies potential pollutants of concern and those chosen for regulation.
6.1 Identification of Airport Deicing/Anti-icing Stormwater Pollutants
Airport deicing stormwater is generated when airfield deicing chemicals and ADFs mix
with stormwater (either directly or because of snowmelt). Because deicing stormwater is
weather-dependent, it is highly variable in nature and pollutant concentrations may vary greatly.
In addition, other airport-related activities, including aircraft fueling and maintenance activities,
may contribute pollutants to stormwater that is also contaminated with deicing chemicals.
Because of the inherent difficulties in characterizing pollutants resulting solely from deicing
activities, EPA evaluated pollutants detected in deicing stormwater, pollutants present in source
water, and pollutants that are present in ADFs and airfield deicers prior to use to determine the
pollutants likely to be present in deicing stormwater.
EPA considered multiple sources of information to identify potential pollutants of
concern associated with deicing stormwater including the following:
EPA sampling data from the PDS;
NPDES permits for airports to determine pollutants that are currently monitored
or limited at airports;
EPA sampling data collected during the 2004/2005 and 2005/2006 deicing
seasons to identify pollutants present in untreated deicing stormwater;
EPA sampling data collected during the 2004/2005 and 2005/2006 deicing
seasons to determine pollutants present in source water;
EPA sampling data collected during the 2004/2005 deicing season, current
research, and expert sources to determine ADF constituents; and
Responses to the airport questionnaire.
Airport Deicing Operations PDS
For the PDS, EPA sampled:
Type I ADFs;
Lagoon stormwater from Albany International Airport;
Untreated deicing stormwater from Kansas City International Airport;
Untreated deicing stormwater from Bradley International Airport;
Untreated deicing stormwater from Greater Rockford Airport; and
Stormwater outfalls from Bradley International Airport.
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Section 6 - Pollutants of Concern
The pollutants detected in one or more of these samples were summarized in Table 8-4 of
the Preliminary Data Summary: Airport Deicing Operations report (USEPA, 2000) and are
presented in Table 6-1 of this report.
NPDES Permits
EPA reviewed NPDES individual and general stormwater permits for airports that are
estimated to have significant deicing operations in the United States. The permit review is
summarized in the Airport Deicing Operations NPDES Permit Review Summary memorandum
(ERG, 2007a). Table 6-1 lists pollutants that have monitoring and limit requirements in current
airport NPDES permits.
Pollutants Present in Untreated Deicing Stormwater
Under this rulemaking effort, EPA collected samples at the following six airports during
the 2004/2005 and 2005/2006 deicing seasons:
Detroit Metropolitan Wayne County (DTW) airport;
Minneapolis/St. Paul International (MSP) airport;
Albany International (ALB) airport;
Greater Rockford (RFD) airport;
Pittsburgh International (PIT) airport; and
Denver International (DEN) airport.
Table 6-1 lists pollutants detected in untreated deicing stormwater from these locations.
Pollutants Present in Source Water
Table 6-1 also lists pollutants detected in source water samples at the airports EPA
sampled at during the 2004/2005 and 2005/2006 deicing seasons.
Deicing/Anti-Icing Fluid Constituents
EPA does not have sufficient information on all of the constituents of airfield chemicals
and ADFs to fully characterize them. However, EPA's airport questionnaire does identify which
chemicals and brand-name products are commonly used, which can help to define the pollutants
expected to be in deicing stormwater.
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Section 6 - Pollutants of Concern
Table 6-1. Pollutants Under Consideration as Potential Pollutants of Concern
Analytc
Pollutants
Identified in
the PDS
Sampling
Pollutants
Monitored in
NPDES
Permits
Pollutants Identified in
Raw ADF in Research or
2004-2006 EPA
Sampling
Pollutants Identified in
Untreated Storm water
in 2004-2006 EPA
Sampling
Pollutants Identified in
Sou rce Water in 2004-
2006 EPA Sampling
Classicals/Conventionals
Alkalinity
X
X
nh3-n
X
X
X
X
bod5
X
X
X
X
COD
X
X
X
Chloride
X
X
X
Dissolved Oxygen
X
Hardness
X
X
Oil & Grease
X
SGT-HEM
X
X
HEM
X
X
X
no3-n + no2-n
X
X
X
Sulfate
X
X
X
TDS
X
X
TKN
X
X
X
TOC
X
X
X
X
Total Orthophosphate
X
X
Total Phosphorus
X
X
X
Total Petroleum Hydrocarbons (TPH)
X
Total Recoverable Phenolics
X
X
TSS
X
X
Metals
Aluminum
X
X
Antimony
X
X
X
Arsenic
X
X
X
Barium
X
X
X
Boron
X
X
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Technical Development Document for Effluent
Limitation Guidelines and Standards for the Airport Deicing Category
Section 6 - Pollutants of Concern
Table 6-1 (Continued)
Analyte
Pollutants
Identified in
the PDS
Sampling
Pollutants
Monitored in
NPDES
Permits
Pollutants Identified in
Raw ADF in Rescareh or
2004-2006 EPA
Sampling
Pollutants Identified in
Untreated Stormwater
in 2004-2006 EPA
Sampling
Pollutants Identified in
Sou rce Water in 2004-
2006 EPA Sampling
Cadmium
X
Calcium
X
X
X
X
Chromium
X
X
Copper
X
X
X
X
X
Iron
X
X
X
X
Lead
X
X
Magnesium
X
X
X
X
Manganese
X
X
Mercury
X
X
Molybdenum
X
X
Potassium
X
Selenium
X
X
Silver
X
Sodium
X
X
X
X
Thallium
X
Tin
X
X
X
Titanium
X
Vanadium
X
Zinc
X
X
X
X
X
Organics
Acetone
X
X
Benzene, toluene, ethylbenzene, xylene
(BTEX)
X
X
Benzoic Acid
X
Bis(2-Ethylhexyl) Phthalate
X
Di-n-butyl Phthalate
X
Diethylene Glycol
X
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Technical Development Document for Effluent
Limitation Guidelines and Standards for the Airport Deicing Category
Section 6 - Pollutants of Concern
Table 6-1 (Continued)
Analyte
Pollutants
Identified in
the PDS
Sampling
Pollutants
Monitored in
NPDES
Permits
Pollutants Identified in
Raw ADF in Rescareh or
2004-2006 EPA
Sampling
Pollutants Identified in
Untreated Stormwater
in 2004-2006 EPA
Sampling
Pollutants Identified in
Sou rce Water in 2004-
2006 EPA Sampling
N-Dodecane
X
EG
X
X
X
N-Hexadecane
X
Methyl Ethyl Ketone
X
Naphthalene
X
Phenol
X
X
PG
X
X
X
X
N-Tetradecane
X
1,2,4- Trimethylbenzene
X
Trichloroethene
X
Tolyltriazole
X
Benzotriazole
5 -Methyl- lH-benzotriazole
X
Alkylphenols
Nonylphenol, total
X
X
Nony lphenol-1 -Ethoxylate
X
X
Nonylphenol-2-Ethoxylate
X
X
Nony lphenol-3 -Ethoxylate
X
X
Nonylphenol-4-Ethoxylate
X
X
Nony lphenol-5 -Ethoxylate
X
X
Nonylphenol-6-Ethoxylate
X
X
Nony lphenol-7 -Ethoxylate
X
X
Nonylphenol-8-Ethoxylate
X
X
Nonylphenol-9-Ethoxylate
X
X
Nonylphenol- 10-Ethoxy late
X
X
Nonylphenol-11 -Ethoxylate
X
X
Nonylphenol- 12-Ethoxy late
X
X
X
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Technical Development Document for Effluent
Limitation Guidelines and Standards for the Airport Deicing Category
Section 6 - Pollutants of Concern
Table 6-1 (Continued)
Analyte
Pollutants
Identified in
the PDS
Sampling
Pollutants
Monitored in
NPDES
Permits
Pollutants Identified in
Raw ADF in Rescareh or
2004-2006 EPA
Sampling
Pollutants Identified in
Untreated Stormwater
in 2004-2006 EPA
Sampling
Pollutants Identified in
Sou rce Water in 2004-
2006 EPA Sampling
Nonylphenol-13 -Ethoxy late
X
X
X
Nonylphenol- 14-Ethoxy late
X
X
X
Nonylphenol-15 -Ethoxy late
X
X
X
Nonylphenol- 16-Ethoxy late
X
X
X
Nonylphenol- 17-Ethoxy late
X
X
X
Nonylphenol-18-Ethoxy late
X
X
X
Octylphenol
X
X
Octylphenol-2-Ethoxy late
X
X
Octy lphenol-3 -Ethoxy late
X
X
Octylphenol-4-Ethoxylate
X
X
Octy lphenol-5 -Ethoxy late
X
X
Octylphenol-6-Ethoxylate
X
X
Octy lphenol-7 -Ethoxy late
X
X
Octylphenol-8-Ethoxylate
X
X
Octylphenol-9-Ethoxylate
X
X
Octylphenol-10-Ethoxy late
X
X
Octylphenol-11 -Ethoxy late
X
X
Octylphenol-12-Ethoxy late
X
X
Total Nony lphenol-3-Ethoxy late-
Nonlyphenol-18-Ethoxy late
X
X
X
Total Octylphenol-2-Ethoxylate-
Octy lphenol-12-Ethoxy late
X
X
Note: Octylphenol and nonylphenol should have a higher toxicity than the alkylphenol ethoxylates.
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Limitation Guidelines and Standards for the Airport Deicing Category
Section 6 - Pollutants of Concern
The commonly used airfield deicing and anti-icing chemicals are listed below, along with
the approximate percentage of total airfield deicing chemical usage they comprise:
Potassium acetate (64 percent);
Propylene glycol-based fluids (12 percent);
Urea (11 percent);
Sodium acetate (9 percent);
Sodium formate (3 percent); and
Ethylene glycol-based fluids (2 percent).
EPA has two sources of data on the constituents of ADF. First, EPA collected and
analyzed samples of unused, or "raw," ADF during the sampling episodes at DTW and MSP.
Table 6-1 lists the chemical compounds for which EPA analyzed the raw ADF samples. Second,
EPA reviewed research conducted by USGS to determine potential ADF constituents. Steven
Corsi of USGS conducts research and sampling on ADF and deicing stormwater at General
Mitchell International Airport in Milwaukee, WI. He has published several papers presenting his
research and sampling results and has identified the following pollutants in ADF stormwater and
snowmelt:
BOD5;
COD;
PG and EG;
AP and APEO; and
Benzotriazole (BT) and its methylated derivatives (MeBT).
6.2 Pollutants of Concern Selection Criteria
Having identified pollutants that are likely to be present in airport deicing stormwater,
EPA then considered which pollutants should be pollutants of concern. EPA considered the
following criteria in assessing potential pollutants of concern for the airport deicing industry:
Whether the pollutant can be directly linked to deicing/anti-icing chemicals;
Whether the pollutant is detected in the effluent from a small number of airports
and is uniquely related to those facilities; or
Whether the pollutant can be analyzed using an EPA-approved or other
established method.
After considering the criteria listed above, EPA developed a list of those pollutants that
are considered potential pollutants of concern.
6.3 Identification of Potential Pollutants of Concern
EPA compared the pollutants detected in deicing stormwater to ADF and airfield deicer
constituents and determined that many pollutants present in the stormwater are not present in
ADF or airfield deicers. Stormwater contains pollutants from sources other than ADF and
airfield deicers; these sources may include, but are not limited to, the following:
Source water pollutants (present in the water used at the airport facility);
Pollutants from aircraft and vehicle fueling;
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Pollutants from maintenance-related operations; or
Pollutants from roof runoff.
EPA also considered the other criteria listed in Section 6.2 to assess potential pollutants
of concern. Below is a summary of EPA's evaluation of potential pollutants of concern by the
following analytical categories: classical/conventional parameters, metals, and organic
pollutants.
Classical/Conventional Parameters
The major components of both airfield deicing chemicals and ADFs are organic and
degrade in the environment after their release. Because of this, COD and BOD5 concentrations
are generally high in deicing stormwater. Both of these pollutant parameters are also good
indicators of the amount of acetates, urea, glycols, and formates in deicing stormwater.
EPA believes that those airports with discharge permits requiring monitoring and control
of ammonia, TKN, and nitrate/nitrite are likely doing so to monitor discharges of urea.
Information collected during EPA's airport site visits seemed to indicate that airports have been
phasing out the use of urea for airfield deicing. However, EPA's analysis of urea use from the
airport questionnaire showed an increase during the 2002/2003 through 2004/2005 deicing
seasons, with approximately the same number of airports using urea in each of those seasons.
Several of the classical parameters detected in deicing stormwater are from nondeicing
stormwater, dilution water, or other airport operations. Based on information on airfield deicers
and analysis of raw ADF, EPA concludes these pollutants are not present in ADF or airfied
deicers but are present in deicing stormwater. Pollutants from airport sources aside from
ADF/airfied deicers include alkalinity, hardness, oil and grease, TDS, and TSS.
Other classical/conventional parameters (including chloride, TOC, and total phosphorus)
are found in source water, which is used to dilute ADF/airfield deicers prior to application.
Therefore, EPA concluded these pollutants are not present in ADF/airfield deicers.
Finally, while total recoverable phenolics are present in EPA sampling results, the
phenols in ADF are widely reported as alkylphenols and octylphenols; therefore, EPA chose the
analyte-specific results and not the bulk parameter as the more appropriate indicator of phenols
in ADF.
Metals
Multiple metals have been detected in samples of airport deicing stormwater. Some of
these metals were also detected in the ADF samples collected by EPA. Many of these metals are
not original components of deicing products (e.g., aluminum and seleniun); they are present as
background concentrations from the stormwater or source water used for ADF dilution or they
are metals picked up by stormwater runoff from aircraft maintenance/operation areas or building
roofs.
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Nonyl/Octyl-Phenol-Ethoxylates
EPA sampling data shows the presence of both nonylphenol and octylphenol ethoxylates.
EPA decided to use the total octylphenol and total nonylphenol ethoxolates as the indicator for
all ethoxolates.
Organic Pollutants
Organic pollutants present in deicing stormwater include PG, EG, triazole compounds,
alkylphenols, and alkylphenol ethoxylates. Other organics may also be present from the
breakdown of glycols, urea, acetates, and formates.
Pollutants of Concern
Based on this evaluation of available data, EPA identified the following as potential
pollutants of concern for the Airport Deicing Category:
COD;
BOD5;
EG;
PG;
Benzotriazole;
5-Methyl-lH-benzotriazole;
Nonylphenol, total;
Octylphenol, total;
Total nonylphenol-3-ethoxylate-nonlyphenol-18-ethoxylate;
Total octylphenol-2-ethoxylate-octylphenol-12-ethoxylate;
Ammonia as nitrogen;
Nitrate/Nitrite;
TKN;
Aluminum;
Antimony;
Boron;
Cadmium;
Chromium;
Iron;
Lead;
Magnesium;
Mercury;
Molybdenum;
Potassium;
Selenium;
Thallium;
Tin;
Titanium;
Vanadium;
Zinc; and
Acetone.
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Section 6 - Pollutants of Concern
6.4 Selection of Regulated Pollutants
Table 6-2 lists the potential pollutants of concern identified in Section 6.3, along with an
explanation of whether EPA selected the pollutants for regulation. Based on the documented
environmental impacts from stormwater contaminated with airport deicing materials, EPA
focused on regulating those pollutants exerting oxygen demand and contributing toxicity to
receiving water bodies. EPA found that the impacts of slug loads of ADF stormwater on the
dissolved oxygen of receiving streams, as well as color and odor issues associated with high
ADF concentrations in stormwater discharge, are well documented. The main component of
ADF is glycol, which exhibits significant oxygen demand. Research by Corsi (Corsi et al., 2006)
also identified potential toxicity concerns that may be linked to ADF additives, specifically
triazoles and alkylphenols. ADF manufacturers have told EPA that the use of triazole compounds
in ADF is being discontinued and that triazole use in European ADFs has been phased out.
Alkylphenols and their ethoxylates have also been identified as potential toxic components of
ADF. EPA's sampling data have confirmed the presence of these compounds; however, EPA
believes that insufficient information is currently available to fully characterize the extent to
which these compounds are present in deicing stormwater and their impact. In addition, there is
not currently an approved EPA method (in 40 CFR Part 136) for these compounds.
For stormwater discharges from airfield deicing operations, EPA focused on the
continued use of urea. Urea breaks down into ammonia, and the resulting ammonia toxicity in
receiving streams has helped to discourage urea use as an airfield deicing chemical in the past.
When inadequately treated, urea-contaminated wastewater also may contribute to nitrogen
enrichment and eutrophication of receiving waters. Alternative airfield deicing chemicals,
predominantly comprising a salt ion (potassium or sodium) and either acetate or formate, are
available that are less toxic than ammonia.
Based on the known environmental impacts from deicing stormwater discharges, EPA
has selected COD and ammonia (as N) for regulation. COD is a good indicator parameter to
monitor the overall oxygen demand resulting from the discharge of glycol-based ADFs and any
other organic constituents present in the stormwater. Ammonia as N is selected for regulation to
ensure that airports cease using urea as an airfield deicer, since other less toxic products are
available.
EPA evaluated the impacts of the airport deicing collection and treatment scenarios on
both BOD5 and COD discharges. EPA selected COD for regulation and not BOD5 for the
following reasons:
COD analyses are simple to conduct and can be measured in real time compared
to a 5-day test for BOD;
COD eliminates the need to consider receiving water temperature when
evaluating water quality concerns; and
Toxic ADF additive compounds in deicing stormwater may have a negative and
variable affect on the acclimation of the active cultures used in BOD analysis,
making the method less robust than COD analysis for these wastewaters.
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Section 6 - Pollutants of Concern
Table 6-2. Potential Pollutants of Concern Selected for Regulation
Potential Pollutant of Concern
Selected for
Regulation
Explanation of Selection or Nonselection for Final Rule
BOD5
COD as surrogate
COD
X
Selected for regulation
Ethylene glycol
COD as surrogate
Propylene glycol
COD as surrogate
Benzotriazole
Limited data available to support selection; potential
discontinued use
5 -Methyl- lH-benzotriazole
Limited data available to support selection; potential
discontinued use
Nonylphenol, Total
Limited data available to support selection; no current
EPA-approved method for analysis
Octylphenol, Total
Limited data available to support selection; no current
EPA-approved method for analysis
Total nonylphenol-3-ethoxy late-
no nlyphenol- 18-ethoxylate
Limited data available to support selection; no current
EPA-approved method for analysis
Total octylphenol-2-ethoxylate-
octylphenol- 12-ethoxylate
Limited data available to support selection; no current
EPA-approved method for analysis
Ammonia as nitrogen
X
Selected for regulation to monitor urea use
Nitrate/Nitrite
Ammonia as nitrogen as surrogate for urea use
TKN
Ammonia as nitrogen as surrogate for urea use
Aluminum
Limited impact data for metals; insufficient data to support
ADF as sole source of metal contamination
Antimony
Limited impact data for metals; insufficient data to support
ADF as sole source of metal contamination
Boron
Limited impact data for metals; insufficient data to support
ADF as sole source of metal contamination
Cadmium
Limited impact data for metals; insufficient data to support
ADF as sole source of metal contamination
Chromium
Limited impact data for metals; insufficient data to support
ADF as sole source of metal contamination
Iron
Limited impact data for metals; insufficient data to support
ADF as sole source of metal contamination
Lead
Limited impact data for metals; insufficient data to support
ADF as sole source of metal contamination
Magnesium
Limited impact data for metals; insufficient data to support
ADF as sole source of metal contamination
Mercury
Limited impact data for metals; insufficient data to support
ADF as sole source of metal contamination
Molybdenum
Limited impact data for metals; insufficient data to support
ADF as sole source of metal contamination
Potassium
Limited impact data for metals; insufficient data to support
ADF as sole source of metal contamination
Selenium
Limited impact data for metals; insufficient data to support
ADF as sole source of metal contamination
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Limitation Guidelines and Standards for the Airport Deicing Category
Section 6 - Pollutants of Concern
Table 6-2 (Continued)
Potential Pollutant of Concern
Selected for
Rcgu lation
Explanation of Selection or Nonselection for Final Rule
Thallium
Limited impact data for metals; insufficient data to support
ADF as sole source of metal contamination
Tin
Limited impact data for metals; insufficient data to support
ADF as sole source of metal contamination
Titanium
Limited impact data for metals; insufficient data to support
ADF as sole source of metal contamination
Zinc
Limited impact data for metals; insufficient data to support
ADF as sole source of metal contamination
Acetone
COD as surrogate
EPA is not regulating metals in the final airport deicing rule. Given the potential for
background interference from airport operations, EPA does not have sufficient data to support
metals as a unique pollutant from ADF alone.
6.5 References
Corsi, S.R., et al. 2000. "Aircraft and Runway Deicers at General Mitchell International Airport,
Milwaukee, Wisconsin, USA. Biochemical Oxygen Demand and Dissolved Oxygen in
Receiving Streams." (November 22). DCN AD00081.
Corsi, S.R., et al. 2003. "Nonylphenol Ethoxylates and Other additives in Aircraft Deicers, Anti-
icers, and Waters Receiving Airport Runoff." Environmental Science & Technology, 37:4031-
4037. DCN AD00083.
Corsi, S.R., et al. 2006. "Characterization of Aircraft Deicer and Anti-icer Components and
Toxicity in Airport Snowbanks and Snowmelt Runoff." Environmental Science & Technology.
DCN AD00326.
ERG. 2006. Memorandum from Steve Strackbein and Cortney Itle (ERG) to Brian D'Amico and
Eric Strassler (U.S. EPA). Airport Deicing Operations SWPPP and Permit Review. (November
8). DCN AD00859.
ERG. 2007a. Memorandum from Jason Huckaby (ERG) to Brian D'Amico and Eric Strassler
(U.S. EPA). Airport Deicing Operations NPDESPermit Review Summary. (April 16). DCN
AD00611.
ERG. 2007b. Memorandum from Maureen Kaplan (ERG) to Mary Willett (ERG). Toxic
Weighting Factors (TWFs) for Nonylphenol, Octylphenol, and Alky I Phenol Ethoxy late. (March
30). DCN AD00862.
USEPA. 2000. Preliminary Data Summary: Airport Deicing Operations. U.S. Environmental
Protection Agency. Washington, D.C. EPA-821-R-00-016. (August).
http://www.epa.gov/guide/airport.
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Section 6 - Pollutants of Concern
USEPA. 2006. Toxic Weighting Factor Development in Support of CWA 304(m) Planning
Process. U.S. Environmental Protection Agency. Washington, D.C. (June). DCN AD00861.
USEPA. 2007. Ecotoxicology ("ECOTOX") Database. U.S. Environmental Protection Agency.
Washington, D.C. Available online atwww.epa.gov/ecotox/.
USGS. 2004. Data Summary for Monitoring and Assessment of Changes in Water Quality Due
to Deicer Management Water Years 1997-2004. General Mitchell International Airport and U.S.
Geological Survey. (September). DCN AD00085.
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Section 7 - Collection and Treatment Technologies Applicable to Airport Deicing Operations
7. Collection and Treatment Technologies Applicable to Airport
Deicing Operations
The NPDES permit program, along with the emergence of problems such as fish kills and
odor reports, have prompted airports and airlines to investigate a wide range of pollution
prevention and treatment practices. These practices are designed to eliminate or minimize the
environmental impact of ADF without compromising safety. This section summarizes the
common techniques used to collect deicing stormwater and the treatment steps implemented
prior to discharge. This section also discusses pollution prevention practices used by U.S.
airports and airlines.
Each method of collection, treatment, or pollution prevention selected by an airport or
airline often depends on a variety of airport-specific or airline-specific factors, including climate,
amount of deicing and anti-icing agents applied, number of airlines operating at a particular
airport, aircraft fleet mix, number of aircraft operations, costs, presence of existing infrastructure,
availability of land, and effect on aircraft departures. EPA recognizes that some of the practices
discussed in this section may not be practical or economically feasible for all U.S. airports.
EPA evaluated whether regulation of airfield deicing stormwater was practical or cost-
effective. Because airfield deicing stormwater losses tend to occur over large areas and the
volumes of dilute stormwater may be very high, at this time EPA could not identify an
"economically achievable" means to regulate airfield deicing stormwater other than to encourage
a complete transition away from urea use. Therefore, the technologies presented in this section
are primarily used to collect and treat ADF-contaminated stormwater.
Section 7.1 discusses deicing stormwater collection, Section 7.2 describes deicing
stormwater treatment, Section 7.3 discusses glycol recycling, and Section 7.4 presents pollution
prevention (e.g., product substitution) practices.
7.1 Deicing Stormwater Collection
The collection of deicing stormwater from aircraft deicing/anti-icing operations helps
prevent or minimize discharges at stormwater outfalls. Airports currently use a variety of
collection and conveyance methods, including designated aircraft deicing pads, gate and ramp
area drainage collection systems, plug and pump systems, and specially designed glycol
collection vehicles (GCVs), each of which is discussed in Section 7.1.1. Individual airports often
rely on a combination of these collection strategies to effectively collect ADF-contaminated
stormwater.
Section 7.1.2 presents common methods for storing and discharging deicing stormwater,
including detention ponds or constructed wetlands, retention ponds, permanent storage tanks or
frac tanks, discharge to a POTW, trucking waste off site, or any combination of these methods.
The following sections describe in detail the various wastewater collection methods used by the
industry.
7.1.1 Deicing Stormwater Collection and Conveyance
This section describes the various wastewater collection and conveyance methods
commonly used by airports. Airport stormwater collection systems are designed to collect
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deicing stormwater from several different locations at which deicing operations are performed,
including aircraft deicing at CDPs, at the gates, or at parking or cargo aprons. Collection systems
may collect stormwater from airfield deicing locations including ramps, taxiways, and runways.
Common methods of collecting and conveying deicing stormwater include deicing pad collection
systems, gate and ramp area drainage collection systems, plug and pump systems, and GCVs.
Deicing Pads
A CDP is a facility on an airfield built specifically for aircraft deicing operations. It is
typically a paved area adjacent to a gate area, taxiway, or runway, and constructed with a
drainage system separate from the airport's main storm drain system. It is usually constructed of
concrete with sealed joints to prevent the loss of sprayed ADF through the joints. The pad's
collection system is typically connected to a stormwater storage facility, from which the spent
ADF may be sent to an on-site or off-site treatment facility.
Deicing pads restrict aircraft deicing to a confined area, allowing the deicing stormwater
to be captured at the point of generation and thereby minimizing the volume of sprayed deicing
fluid discharged in an uncontrolled manner. Aircraft deicing pads also centralize deicing
activities, which allows airports to more easily collect high-concentration ADF-contaminated
stormwater. Transporting ADF-contaminated stormwater off site to wastewater treatment plants
or POTWs is also more economical when the amount of deicing stormwater is minimized.
One benefit of deicing departing aircraft on deicing pads instead of at the gates is that it
frees the gates for use by arriving aircraft. Another benefit is that pads are commonly located
near the heads of runways, where planes can be deiced just prior to takeoff, potentially reducing
the amount of Type IV anti-icing fluid necessary due to shorter holdover times and the amount of
glycols transferred from the deicing pad or released into the air. Figure 7-1 shows an example of
a CDP with fixed boom sprayers.
Figure 7-1. Deicing Pad Equipped with Fixed Deicing Booms at Pittsburgh Airport
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Gate and Ramp Area Drainage Collection Systems
Other than deicing pads, the most common areas for deicing operations are passenger
terminal gates and aircraft parking or cargo ramps/aprons. To collect wastewater generated at
these locations, some airports have installed collection systems or modified existing stormwater
drainage systems. The typical collection system consists of graded concrete pavement with
trench or square drains that convey wastewater to a storage facility or discharge point through a
diversion box. Gate and ramp collection systems generally generate low-concentration ADF-
contaminated stormwater because more stormwater is mixed in with the ADF and because there
are increased fugitive losses due to vehicle traffic around the planes. For some stormwater
drainage systems, a diversion box allows uncontaminated stormwater to be diverted to
stormwater outfalls.
Plug and Pump Systems
Plug and pump collection systems generally comprise devices and equipment that alter an
airport's existing storm drain system to contain and collect ADF-contaminated stormwater to
prevent ADF-contaminated stormwater from entering the storm drain system. These systems
include, but are not limited to, temporary blocking devices at storm drain inlets and/or shutoff
valves in the storm sewer system. Some airports use storm drain inserts or plugs to close the
drains and allow the ADF-contaminated stormwater to collect within the existing airport
stormwater drainage system. When aircraft are undergoing deicing/anti-icing, the inserts are
installed to force contaminated stormwater to pool in drainage piping until it can be vacuumed
or pumped out. This practice prevents manholes and stormwater piping from overflowing. Once
deicing/anti-icing activity ends and the contaminated stormwater is removed, the storm drain
inserts can be removed, or deactivated allowing uncontaminated stormwater to pass through the
drain. Plug and pump collection systems are applicable to airports that deice at the gate and may
be utilized to convert ramp areas (e.g., cargo, feeder, taxiways) into deicing areas. One benefit of
deicing at the gate is that the components of the existing collection system infrastructure (i.e.,
existing storm sewers) can be incorporated into the plug and pump collection system, reducing
the costs associated with deicing control.
Minneapolis/St. Paul International (MSP) airport is one example of an airport using a
plug and pump collection system. At MSP airport, 30 percent of deicing operations takes place in
the airport's 16 plug and pump containment areas. During the deicing season, the plug and pump
areas are fitted with compression plugs in the storm sewers to prevent contaminated or
potentially contaminated stormwater from being discharged. The stormwater plugs convert the
stormwater sewer pipes and manholes into individual stormwater retention systems that can each
retain between 5,000 to 42,000 gallons of stormwater. These individual stormwater retention
systems are monitored during the day to determine how full they are (to prevent overflow) and to
determine how to manage the ADF-contaminated stormwater based on its composition and
strength. Contaminated stormwater is pumped or vacuumed from the sewer pipes and tested to
determine the glycol concentration. Based on the glycol concentration of the wastewater, it is
stored in either a low-concentration storage tank or a high-concentration storage tank prior to
being shipped off site (USEPA, 2008a).
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GCVs
GCVs are specially designed vehicles that remove stormwater contaminated with deicing
materials from airport deicing pads and gate locations by vacuuming liquid from pavement
surfaces. GCVs help prevent ADF losses through evaporation and/or direct discharge and allow
ADF-contaminated stormwater to he collected for treatment or disposal. Drain covers that bond
to surfaces to quickly seal off drains are often used in conjunction with GCVs in the area where
aircraft are deiced to allow the GCVs to collect high-concentration spent deicing fluid.
Commercial GCVs have two basic designs: truck chassis or trailer mounted. The truck
chassis designs are adapted from the street sweeper concept, with a vacuum unit,
vacuum/sweeper head, and storage tank all mounted on a single self-propelled vehicle.
Typically, a separate engine powers the vacuum system. Trailer-mounted designs have the
vacuum unit, collection head, and storage tank on a towed platform with power provided by
either an engine mounted on the trailer chassis or a power take-off from the tow vehicle,
typically a tractor. Figure 7-2 shows an example of a GCV. GCVs help prevent ADF-
contaminated stormwater from reaching unpaved areas where infiltration could occur and from
contaminating surrounding waterways.
Once ADF-contaminated wastewater is vacuumed from airport surfaces, it is typically
transported to an on-site storage facility (either temporary or permanent) where the airport can
then treat and discharge or ship the waste off site. In addition, some airports with collection and
conveyance or plug and pump systems will have a designated area where the GCV can discharge
into the collection system, allowing the existing infrastructure to convey the material to final
storage.
Figure 7-2. GCV
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Plug and Pump with GCV
Commonly, a plug and pump system is operated in conjunction with GCVs or a tanker
truck with pumps that collect the deicing stormwater that builds up behind the drainage block
during the deicing event. Additionally, GCVs may be used outside of the blocked area to collect
ADF-contaminated stormwater to enhance what can be collected through the plugging operation
alone.
7.1.2 Deicing Stormwater Storage
This section describes the various stormwater storage methods commonly used by
airports. Airport stormwater storage systems are designed to retain deicing stormwater from
several different locations around an airport, accommodate highly variable flows and volumes,
and may retain/store stormwater that contains pollutants from both airfield and aircraft deicers.
Common methods of stormwater storage at airports include detention ponds, equalization ponds,
retentions ponds, and storage or frac tanks.
Detention Ponds/Lagoons and Equalization Ponds
Detention ponds/lagoons are open-water ponds that collect deicing stormwater from
runways and other airport property. Detention ponds and lagoons are designed to temporarily
hold deicing stormwater anywhere from one day to two months and allow solids to settle while
reducing oxygen demand through surface oxygenation and volatilization prior to discharge to
receiving waters. Detention ponds and lagoons can be lined or gravel-filled and may contain
microscopic bacteria that biodegrade deicing and anti-icing materials. Pump stations are
commonly implemented to pump metered wastewater to discharge or further treatment.
Detention basins often use aeration to increase dissolved oxygen levels. Lagoons may be
equipped with a floating cover.
Equalization ponds are detention ponds designed to thoroughly mix ADF-contaminated
stormwater so that consistent concentrations of pollutants can be pumped from the pond to
treatment operations or to other disposal. Equalization ponds may contain moving parts, such as
mixers, to ensure the liquid in the pond is completely mixed.
Retention Ponds
Retention ponds are designed to hold collected deicing stormwater indefinitely. Usually
the pond is designed to allow overflow to drain to another location (e.g., a second retention pond
or other overflow structure) when the water level gets above the pond capacity. Retention ponds
can also be used to treat deicing stormwater as part of a batch process (using chemical addition
and/or aeration) prior to discharge. With retention ponds, airports can collect ADF-contaminated
stormwater throughout a deicing season and have the option of trucking it off site for treatment
or treating it on site in the retention pond.
Advantages and Disadvantages of Ponds in Treating ADF-Contaminated
Stormwater
Ponds require large areas for installation and their wastewater normally requires
treatment for many months after the end of the annual deicing season before it can be discharged.
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FAA discourages airports from installing new stormwater retention ponds, as they can be a lure
for birds, which are a safety hazard for aircraft (FAA, 2007). For airports with existing retention
ponds and adequate storage capacity, aerated pond systems may be able to provide efficient
treatment. See section 7.2.1 for further discussion of aerated pond systems. Figure 7-3 shows an
example of an airport pond used for deicing stormwater storage.
Figure 7-3. Pond for Deicing Stormwater Storage
Storage Tanks
Airports that treat ADF-contaminated stormwater often use tanks to store the stormwater
prior to on-site treatment or transfer off site. These types of tanks can be constructed as
aboveground tanks or underground tanks. Collecting and storing deicing stormwater in storage
tanks allows an airport to equalize pollutant concentrations and flow the stormwater at a
consistent flow rate into an on-site treatment system, which is important to ensuring consistent
treatment results. Portable storage tanks, called frac tanks, can be placed on the airport property
(while empty) and provide temporary storage of collected deicing stormwater. These types of
tanks may also be connected by a hose or pipeline to an alternative area. Figure 7-4 shows an
example of two frac tanks.
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Figure 7-4. Frac Tanks
7.2 Treatment
This section describes the various means of treating stormwater contaminated with
deicing chemicals. The technologies described within this section are typically used to control
ADF-related pollutants; however, stormwater with pollutants from airfield deicing operations
may also be routed into these systems.
7.2.1 Biological Treatment
This section describes the treatment of ADF-contaminated stormwater through biological
processes. Biological treatment consists of two types of processes, aerobic or anaerobic, and can
take place on site at an airport or off site at POTWs or other treatment facilities.
POTW Treatment of ADF-Contaminated Stormwater
Where practical, airports discharge their deicing stormwater to a POTW for biological
treatment. POTW systems generally use activated sludge in an aerobic biological treatment
system and may also incorporate anaerobic digestion of the sludge generated. In aerobic
treatment systems, microorganisms consume the organic matter and convert it to water, carbon
dioxide, and additional biomass in the presence of oxygen. To maintain the microorganism
population in the treatment process, POTWs using an activated sludge process will use an
aerated treatment tank followed by a sludge settling tank. Part of the settled sludge is recycled
back into the aerated treatment tank and the remainder is removed for further processing or
disposal.
Airports may be prevented from discharging ADF-contaminated stormwater to a local
POTW for one or more or the following reasons: (1) limited hydraulic or loading capacity at the
POTW, (2) high POTW wastewater treatment and/or conveyance fees, (3) inability of the local
POTW to handle highly variable pollutant loadings, and/or (4) airport infrastructure constraints.
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Aerated Ponds
Aerated ponds used on site at airports are effective for treating low-concentration ADF-
contaminated stormwater. These are ponds that are open to the atmosphere, though open-topped
tank systems may also be used. Aerated ponds are not generally used for high-concentration
ADF-contaminated stormwater because the ponds do not have sufficient oxygen transfer to
completely convert the ADF pollutants into water, carbon dioxide, and biomass compared to an
activated sludge system. Treatment ponds may range in size and are usually operated as a batch
process.
Aeration in lagoons and ponds increases the level of dissolved oxygen in the water,
which is needed to decompose organic matter such as glycols. In addition, oxygen helps to
oxidize certain elements that are suspended in the water, and oxidation causes some materials to
become heavier so that they will settle out of the water column quicker. Without proper aeration,
bacteria cannot decompose the organic matter in a pond quickly or efficiently. Aeration devices
are used to agitate the lagoon or pond surface, which helps to transfer atmospheric oxygen into
the wastewater to promote biological treatment processes, vent carbon dioxide and other gaseous
elements from the water, and increase the amount of wastewater exposed to ambient air,
allowing other volatile organics to oxygenate and evaporate.
The Greater Rockford airport is an example of an airport operating an aerated pond
treatment system for deicing stormwater. Greater Rockford airport collects ADF-contaminated
stormwater throughout the deicing season into a 16-million-gallon aerated detention pond. Its
aerobic digestion system consists of the aerated detention pond, a settling pond, a re-circulating
pump, and a chemical addition building. The biodegradation of glycol is temperature-dependant
and predominantly occurs during the spring and early summer months when ambient
temperatures are higher. Airport personnel monitor the process, adding nutrients, antifoaming
agents, and pH adjustment chemicals as needed. When the BOD5 concentration of the pond has
been reduced to less than 30 mg/L, airport personnel discharge the treated stormwater from the
settling pond to Rock River (USEPA, 1999).
Figure 7-5 shows an aerated pond installation at Portland Airport (Oregon).
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Figure 7-5. Aerated Pond Installation at Portland Airport
Anaerobic Treatment
Anaerobic treatment systems can effectively treat ADF-contaminated stormwater with a
range of glycol concentrations. This type of treatment usually occurs in a closed tank in which
microscopic bacteria in an oxygen-deficient environment biodegrade deicing and anti-icing
materials. In anaerobic treatment systems, microorganisms consume the organic matter and
convert it to methane and carbon dioxide in the absence of oxygen, which creates much less
sludge than an aerobic system.
AFR treatment is a demonstrated technology for addressing ADF-contaminated
stormwater at both the Albany, New York (ALB) and Akron/Canton, Ohio (CAK) airports.
Additionally, Portland completed construction of an AFB in 2011 and testing is slated to be
complete in 2012. TF Green Airport (Providence, RI) is designing an AFB system, estimated to
be operational in 2015. (Rhode Island Airport Corporation, 2011). The AFB treatment system
uses a vertical, cylindrical tank in which the ADF- contaminated stormwater is pumped upwards
through a bed of granular activated carbon at a velocity sufficient to fluidize, or suspend, the
media. A thin film of microorganisms grows and coats each granular activated carbon particle,
providing a vast surface area for biological growth. The anaerobic microorganisms that develop
occur naturally in sediment, peat bogs, cattle intestines, and even brewer's yeast. Breakdown
products from the AFB treatment system include methane, carbon dioxide and new biomass.
Effluent from the AFB can be discharged to a local POTW or, in most cases, directly to surface
water. Figure 7-6 presents a diagram showing the major components of a typical AFB treatment
system (Source: US Department of Defense, 2003).
Treating wastes using an anaerobic biological system compared to an aerobic system
offers several advantages. Because it does not require aeration, the anaerobic system requires
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less energy and produces less than 10 percent of the sludge of an aerobic process. In addition,
because the biological process is contained in a sealed reactor, odors are eliminated. EPA
evaluated AFB biological treatment as it represents the best technology currently in use by
airports to treat deicing stormwater prior to direct discharge.
Blogas to Boiler
and/or Flare
Separator
Tank
Treated
* Water
Biofilm
Growth
Control
Recycle
Media
Return
Pump
Chemical
Feed
Pump(s)
T Wastewater
Influent
Figure 7-6. Typical Anaerobic Fluid Bed Treatment System for Treatment of ADF-
Contaminated Stormwater
Land Application and Constructed Wetlands
Low-concentration deicing stormwater may also be treated on site at an airport using
either land application or discharge through constructed wetlands. Land application involves
spraying deicing stormwater onto a land surface for infiltration and biological degradation within
the soil. As an example, Salt Lake City International (SLC) airport uses land application to
dispose of batch volumes of low-concentration deicing stormwater on a peri odi c basis. The
system sprays approximately 300,000 to 400,000 gallons of stormwater over nutrient-enriched
land using agricultural wheels. The application is sprayed at a rate of about 1 gallon per square
foot over a two-day period. The sprayed glycol then degrades in the soil over a week to month-
long period (USEPA, 2008b). Because glycol-based ADFs readily degrade in both high clay and
sandy soil systems, this type of system can be effective for low concentrations and limited
volumes. Biodegradation occurs in the soil through carbon respiration of soil microbes, which
consume oxygen and release carbon dioxide. Zurich International Airport, Switzerland, also uses
a spray irrigation system for ADF treatment. At that airport, a heated sprinkler system applies
ADF-contaminated stormwater to a 20 ha (49.4 acre) area (Jungo Engineering Ltd, 2005).
Constructed wetlands are artificial marshes or swamps placed inline with stormwater
drainage at airports. The wetlands act as biofilters and help remove sediments and pollutants
such as heavy metals from the wastewater. Physical, chemical, and biological processes combine
in wetlands to remove contaminants from the wastewater. The discharge from constructed
wetlands can also be collected and treated if it cannot meet discharge permit limits or it can be
discharged to a POTW or surface water.
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7.2.2 Physical Separation
This section describes physical separation processes that are used to treat ADF-
contaminated stormwater. Physical separation consists of four types of processes: filtration,
MVR, membrane separation, and distillation. The treatment can take place on site at an airport or
off site at other treatment facilities.
Filtration
Primary filtration, which removes solids greater than 10 microns, is commonly the first
step in glycol treatment systems because it removes suspended solids and prevents subsequent
processing units from plugging. This technology is typically used in combination with other
technologies. Popular primary filters used in glycol treatment are made of either polypropylene
cartridges or bag filters.
MVR
MVR is an evaporation method that uses mechanically driven compressors or blowers to
increase the pressure of the vapor produced. The increase in pressure causes the vapor's
temperature to increase, which allows it to heat the liquid being concentrated. Benefits of using
MVR in glycol treatment include:
Low specific operating costs;
Low specific energy consumption;
Short residence times of the product; and
Simplicity of the process.
EPA conducted a site visit and subsequent sampling episode at Denver International
(DEN) airport, which operates MVRs in the following manner. MVRs concentrate the deicing
pad storage tank influent, which ranges from 1 to 12 percent PG, to a final concentration of 50 to
55 percent glycol. Each MVR has a capacity of 3,250 gallons per day. The effluent from the
MVRs goes to a storage tank where it is stockpiled prior to being sent to a distillation system
(USEPA, 2007b). The evaporative process may also generate a condensate, which in most cases
requires further treatment prior to indirect discharge. Typically, this is managed via an RO
system, with the concentrated material returned to the treatment process and the RO permeate
discharged to a POTW.
Membrane Separation
Membrane separation is an efficient one- or two-step process that incorporates
ultrafiltration (UF) and/or RO to increase the ADF concentrations of ADF-contaminated
stormwater. In an UF/RO process, fluid is filtered at a high temperature (75ฐ C) using an
ultrafiltration membrane as stage one. Next, the deicing fluid (ultrafiltration filtrate) can be
dewatered using an RO membrane as stage two. The UF membrane is effective at removing
contaminants such as turbidity, color, and odor, and RO stage two is used for dewatering and
glycol separation. The combined UF/RO process produces a final glycol concentration of
approximately 10 percent from an original concentration ranging between 0.5 and 4 percent.
Pittsburgh International (PIT) airport uses this type of system. The PIT system first treats ADF-
contaminated stormwater through an UF unit to remove suspended solids. At this point, the
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stormwater is 0.5 to 4 percent PG. The stormwater is next treated through an RO unit. Following
RO, the stormwater is split into two outputs: 1) concentrate that is approximately 10 percent PG,
and 2) permeate that has a very low glycol concentration. The concentrated PG is transported off
site for further processing and the permeate containing small amounts of glycol, CBOD, and
COD is sent to the POTW for further processing (USEPA, 2006).
Distillation
Distillation can effectively treat ADF-contaminated stormwater by separating the water
from the glycol. A potential drawback of distillation is that it creates a distillate that requires
further treatment. Depending on whether the distillation system is operated in a batch or
continuous mode, the majority of the distillate can be discharged to the local POTW without
further processing. In a batch mode, there is a "mid-cut" water/glycol mixture, which marks the
transition from water removal and product; this volume is redirected to the process feed.
However, depending on system design and applicable limits, distillate may be able to be directly
discharged. Distillation columns may be larger and more expensive than other technologies to
operate, and because distillation is energy-intensive, it is generally not cost-effective to distill
waste glycol solutions at low concentrations (less thanl5 percent). Design variables for this
technology include temperature, distillation column height, and reflux ratio. This process is
commonly done in batches to ensure proper distillation and desired results.
EPA conducted site visits at SLC and DEN airports, both of which operate distillation
columns.
At DEN airport, the distillation system runs 24 hours a day for a three-week cycle
and processes about 225,000 gallons of PG before the system is halted for
cleaning and maintenance. The distillate from the distillation column is
discharged to the airport's storage ponds. The distillation column bottoms
compile sludge that is classified as specialized nonhazardous waste. The 98 to 99
percent PG from the distillation column is pumped to a polisher (USEPA, 2007b).
At SLC airport, 40 to 45 percent glycol-concentrated stormwater is passed
through a finisher (one stage of evaporation) to increase the concentration to
approximately 70 to 80 percent glycol and then discharged to a storage tank. The
stored concentrate is sent to a distillation column where it is heated to 250 to 260
degrees Fahrenheit to produce a final product of 100 percent glycol. Distillate
from the distillation column is discharged to a storage tank prior to RO treatment
and indirect discharge. The column bottoms (residual solids) are disposed of at an
off-site facility landfill (USEPA, 2008b).
7.3 Recycling
Recycling glycol from ADF-contaminated stormwater decreases the amount of ADF-
contaminated stormwater that reaches and potentially impairs surface and ground waters. The
process to recover glycol from ADF-contaminated stormwater may take several steps and can be
conducted both on site at the airport and/or off site at a regional treatment facility. The recycle
and recovery technologies currently in use by U.S. airports include filtration, MVR, membrane
separation, and distillation (discussed in Section 7.2). On-site recycling typically includes some
combination of these technologies, configured as an integrated treatment train to meet specific
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requirements of the airport where it is located. Most commonly, an on-site facility initiates the
process to increase the glycol concentration to make transport to a regional facility for final
processing more cost-effective.
Recovered glycol is generally sold to help recover expenses associated with ADF
application, collection, and control. On-site recycling was successful and economically viable at
the airports visited by EPA that collected large enough volumes of high-concentration ADF-
contaminated stormwater. However, recovery systems may also be able to handle lower
concentration ADF stormwaters (with glycol concentrations in the 1-2 percent range), and small-
and medium-hub airports may be able to recover and recycle glycol using off-site
recycle/recovery facilities. Off-site facilities can recycle ADF-contaminated stormwater from
airports not generating sufficient volumes to warrant on-site recycling and treatment. Glycol
recycling vendors offer a variety of recycle/recovery related services to accommodate different
airport sizes and configurations. Services commonly provided by glycol recycle/recovery
vendors include supplying drain blocks, leasing portable storage tanks, on-call trucking services,
and tote (fluid container) pickups. Key criteria for determining the appropriate recycle/recovery
program include the type of ADF being collected, glycol concentration of the stormwater, total
consumption of ADF per season, and peak ADF volume application rates. Other factors to
consider are the number of deicing days per season at an airport and future air traffic plans.
7.4 Pollution Prevention and Product Substitution Practices
Pollution prevention practices reduce the generation or discharge of pollutants produced
during aircraft/airfield deicing operations. Pollution prevention practices implemented
throughout the aviation industry include infrared deicing, forced-air deicing, product substitution
practices, and BMPs.
Infrared Deicing
Infrared heating involves transmitting energy using electromagnetic waves or rays.
Infrared energy is invisible and travels at the speed of light in straight lines from the heat source
(the emitter) to all surfaces and objects (the receivers) without significantly heating the space
(air) through which it passes. This heating process is much faster than convection or conduction
heating mechanisms used by conventional deicing, where the deicing fluid spray is cooled by
ambient air.
Figure 7-7 shows a picture of the infrared hangar at John F. Kennedy (JFK) airport.
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Figure 7-7. Infrared Hangar at JFK
Infrared-based aircraft deicing systems offer two advantages over traditional glycol-based
deicing methods. From an environmental standpoint, they can greatly reduce the amount of
glycol-based fluids used for aircraft deicing, while from an operational standpoint, they are
relatively inexpensive to operate, as they use natural gas or propane as fuel.
Any infrared deicing facility must take into account the physical characteristics of all
aircraft that will use the system. For example, an infrared system design factors in the maximum
tail height, the shape of tails, maximum wingspans, and differences in the length and width of the
fuselage. The site selected for an infrared deicing system must comply with the same FAA
regulations that apply to glycol-based aircraft deicing facilities, including aircraft separation
rules, airport traffic control tower line-of-sight criteria, and requirements to not interfere with
radar signals, navigational aids, and airport lighting. FAA issued a new Advisory Circular in
2005 specifically for infrared deicing facilities (FAA, 2005). As with traditional aircraft deicing
facilities, an infrared deicing facility must provide taxiways that allow aircraft to bypass the
deicing facility.
While EPA encourages the use of this technology, industry practice has shown that it
may not be applicable at all airports and it appears to be best used in conjunction with other more
conventional deicing operations (ERG, 2004; Belcher-Hoppe Associates, Inc., 2004).
Forced Air Deicing
Forced air deicing uses large volumes of air at low pressure to remove loose
accumulations of snow and ice from an aircraft prior to chemical deicing. Aircraft deicing trucks
or fixed booms equipped with forced air nozzles help reduce the amount of glycol that is used
during deicing and defrosting operations. In light snow conditions, forced air may completely
replace the need for deicing fluid. For light frost and light deicing events, fluid-injected forced
air can be used to reduce the amount of deicing fluid by up to 75 percent. For heavy deicing
events, a fluid forced air technique is used. This technique requires the ADF application rate
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sprayed from the boom to be reduced from 60 gallons per minute (gpm) to 40 gpm to achieve a
25-percent reduction in deicing fluid per aircraft. Forced air deicing can reduce operational
expenses, environmental impacts, and subsequent environmental monitoring or remediation
expenses (Icewolf product flyer; IDS, 2006).
Aircraft Deicing/Anti-Icing Product Substitution Practices
One solution to the environmental problems associated with glycol-based ADF is
replacing such fluids with more environmentally friendly products. ADFs need to meet FAA's
Aerospace Material Specification (AMS) 1424 for Type I fluids and AMS 1428 standards for
Type IV fluids. These standards require a specified level of product performance and
compatibility and any alternative product must meet the same standards. To be economically
viable, alternative products must also be comparably priced and be at least as effective in
maintaining air safety as the glycol-based fluids they replace and less harmful to the
environment.
EPA is aware of one non-glycol, plant-derived product currently being marketed by
Cryotech Deicing Technology. A new Type I ADF product called "DF Sustain" uses 1,3-
propanediol rather than PG, and is manufactured by a fermentation process using cornstarch. The
manufacturer claims performance equal or better than PG- or EG-based deicers.
Table 7-1 lists other aircraft deicing alternatives that EPA is aware of based on literature
reviews, industry meetings, and site visits. In addition, the airport and airline industry
associations as well as U.S. Air Force have conducted and are continuing to conduct research
into other potential substitutes for PG- and EG-based fluids.
Table 7-1. ADF Alternatives
Alternative
Comments
PG
ADF usage data indicates a trend towards greater PG use as an alternative to EG
use.
Hot Air, Forced Air, and
Tempered Steam Deicing
The use of hot air, forced air, or tempered steam when deicing aircraft is an
alternative to typical deicing fluid application techniques using deicing trucks with
conventional spray nozzles alone. These alternatives can provide more effective
deicing than conventional spraying technologies and result in lower ADF usage.
Infrared Deicing
Infrared deicing is an alternative to conventional ADF usage and can greatly reduce
(though not eliminate) the use of ADFs for deicing and anti-icing.
Cryotech Bio-PDO
This bio-based product is currently being marketed as an alternative to
conventional PG-based Type I fluids.
Warm Fuel for Wing Deicing
This type of deicing is an alternative to defrost deicing with ADF.
Airfield Deicing Product Substitution Practices
Environmental problems associated with past airfield deicing products like urea led to the
development of the alternative airfield deicing chemicals used today. Potassium acetate has
replaced urea as the primary airfield deicer at many U.S. airports. The U.S. Armed Forces no
longer purchases airfield deicers that contain urea and instead use potassium acetate, sodium
acetate, and sodium formate. These airfield deicers are highly effective at low temperatures,
exert much lower oxygen demand than urea, and offer less environmental impact.
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The aviation industry is currently evaluating the impact of common airfield deicing
chemicals on the environment, runway infrastructure, and chemical corrosion of aircraft carbon
brakes. Based on the results of this work, EPA anticipates that alternative airfield deicing
chemicals will be identified and ultimately incorporated into practice. EPA is aware of one such
product, Cryotech's Bio-PDO2, which is currently being used as an additive for potassium
acetate runway deicers. The Cyrotech BX36 runway product performs similarly to its widely-
used E36 product, but with reductions in electrical conductivity and potassium content (reducing
carbon brake issues), and a bio-based material composition of 75 percent, allowing for easy
degradation.
BMPs
BMPs are techniques used to limit the amount of ADF applied or allowed to mingle with
stormwater. EPA defines a BMP as a "technique, measure or structural control that is used for a
given set of conditions to manage the quantity and improve the quality of stormwater in the most
cost-effective manner." This section describes the following aircraft/airfield deicing-related
BMPs:
Application rates and deicing fluid dilution;
Airfield prewetting;
Ice detection systems;
Enhanced weather forecasting;
Heated sand;
Separation of contaminated snow;
Annual employee training;
Mechanical deicing and snow removal;
Yearly inspections of deicing equipment and infrastructure; and
Type IV anti-icing.
Application Rates and Deicing Fluid Dilution
Deicing personnel can minimize the amount of deicing fluid used at an airport by varying
deicing fluid application rates and the ADF dilution mix to best match each deicing event
condition. Application rates are commonly evaluated every time deicing is required. However,
ADF is usually premixed to a set 55 percent or 45 percent glycol concentration. Systems that
allow for ADF dilution adjustment based on the weather conditions can use less. Ice thickness,
ambient temperatures, and plane size all determine application rates and fluid dilution
requirements. Small planes with small amounts of frost can require as little as 50 gallons of ADF
while large planes with thick ice accumulations can take up to 2,000 gallons to deice.
Application rates controlled by chemical metering systems installed to deicing trucks or booms
allow the applicator to control the distribution of chemicals and maintain a consistent application
rate at all times. Using a chemical metering system also allows the operator to change the
application rate in mid-application based on changing weather conditions.
2 Mention of Cryotech products should not be construed as an endorsement from EPA.
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Airfield Prewetting
Airfield prewetting involves applying a dry chemical followed by a light coating of liquid
deicer to airfield pavement. During icy conditions, a granular deicer is generally used to
penetrate ice and increase surface area prior to using a liquid deicer (generally PG) to help the
solid deicer stick to the pavement and prevent dry pellets from blowing off. Responses to EPA's
airport questionnaire indicated that prewetting is common and helps lower the cost of materials
by increasing the rate at which the liquid deicer contacts icy surfaces and by minimizing wind
losses of solid deicer. Following prewetting, snow and ice are generally removed from airfield
areas using mechanical equipment (such as plows and brooms).
Ice Detection Systems
Ice detection systems include sensors installed on runways and taxiways that transmit
constant surface and subsurface temperature readings to deicing control personnel. These sensors
indicate whether there is a potential for ice to form on the paved surfaces. Airports can then use
the information provided by individual deicer manufacturers to determine whether to apply
deicing/anti-icing chemicals.
Enhanced Weather Forecasting
Many of the larger U.S. airports use enhanced weather forecasting systems to help
determine when they will require deicing activities. A popular weather forecasting product on the
market is the Weather Support to Deicing Decision Making (WSDDM) software program. This
system is a "nowcasting" system that is used to confirm National Weather Service data and
forecasts. WSDDM provides forecasts, monitors storms and provides real-time storm
information, and estimates and detects precipitation. WSDDM can provide the following
services to the user:
1. Real-time snow gauge data (updated every minute) of the liquid equivalent
snowfall rate at the airport and two to three sites 10 to 20 kilometers (km) away
from the airport;
2. Real-time radar reflectivity from radars depicting current locations of
precipitation and snow;
3. Meteorological data at the airport and two to three sites 10 to 20 km away from
the airport updated every minute and displayed in text and time line form, with
the time line going back two hours;
4. Thirty-minute nowcast of radar reflectivity based on a cross-correlation technique
on the radar reflectivity data updated every six minutes; and
5. Thirty-minute nowcast of liquid equivalent snowfall rate at the airport and the off-
site snow gauge locations by applying a real-time snow gauge-radar reflectivity
calibration algorithm at each of the snow gauge sites, updated every six minutes.
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WSDDM can improve pollution prevention by pinpointing when deicing operations are
actually needed, which lowers the amount of ADFs used to keep departing aircraft free of ice and
snow at takeoff and lowers the amount of anti-icing chemicals used to prevent ice and snow from
bonding to aircraft and taxiways (ERG, 2005).
Heated Sand
Sand trucks can be parked in a heated garage with heat piped to the truck. Heating sand
trucks accomplishes two things. First, heating the truck prevents the moisture in the sand from
freezing and clumping, which would prevent the sand from being efficiently disbursed when
applied. Second, applying heated sand to icy surfaces can melt ice and the sand provides needed
traction when the surfaces refreeze, which minimize the need to use pavement deicers.
Separation of Contaminated Snow
Airports often segregate glycol-contaminated snow (commonly called "pink snow") and
haul it to a designated area where the snow melt can be collected. Deicing pads often contain
designated areas to store contaminated snow so that the snow melt can be commingled with other
deicing stormwater.
Annual Employee Training
Training and experience of personel performing aircraft deicing/anti-icing operations
affects the efficiency of aircraft deicing/anti-icing. Well-trained and experienced deicing/anti-
icing personnel improve the efficiency of aircraft deicing/anti-icing operations and minimize the
volume of ADF used. The training and experience of airport personnel may also affect the
efficiency of airfield deicing operations. Airport personnel are typically responsible for clearing
taxiways, gate areas, ramps, aprons, and deicing pads. When these areas are not adequately
cleared, snow and ice accumulate on the undercarriage and the underside of aircraft during
taxing and must be removed prior to takeoff.
Many airports conduct annual operations and maintenance training, with specialized
winter operations training usually conducted prior to the deicing season. This specialized training
can include but is not limited to proper use of equipment, application of chemicals, and location
of snow melt areas. Staff may also be trained in environmental awareness detailing the
requirements of airport permits and BMPs associated with airport deicing/anti-icing operations.
Mechanical Deicing and Snow Removal
The amount of ADF required to deice aircraft can be minimized by mechanically deicing
the aircraft prior to chemical deicing. Mechanical deicing is generally economical only for small
aircraft because mechanical deicing of large aircraft is labor-intensive and time consuming. A
drawback of mechanical deicing is that aircraft (e.g., aircraft antennae and sensors) risk being
damaged by incorrect mechanical deicing methods. Despite the risk of aircraft damage, many
airlines use brooms, squeegees, and ropes, among other items, to remove ice and snow from
aircraft surfaces. These methods are more effective at removing snow rather than ice.
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Snow is commonly mechanically removed on airfield pavement, including passenger
ramps, gate positions, taxiways, and runways, prior to ADF being applied, to prevent
contamination of the snow. The following types of equipment are used to remove snow from
airfield surfaces: self-propelled snow brooms, high speed snow blowers and snow plows, and
utility trucks or tractors fitted with snow brooms or plows. Physical means are generally used to
remove snow rather than ice.
Yearly Inspections of Deicing Equipment and Infrastructure
Inspections are conducted to ensure that equipment used for deicing operations is
working properly and to determine where maintenance may be needed. Storage tanks are
inspected to ensure there are no leaks. ADF application equipment is inspected to determine if
gauges are working properly and that fluid is not being spilled. Trench or square drains are
inspected to ensure there is no clogging and that water conveyed through the drain does not
escape. Other equipment and airport infrastructure may require yearly inspections to make
certain that deicing chemicals are applied with properly functioning equipment and collected
with suitable infrastructure.
Type IV ADF Anti-icing
Type IV ADF protects aircraft from ice, snow, or slush accumulations on cleaned aircraft
surfaces. Type IV fluids form a protective film on treated surfaces, protecting against ice
formation and/or snow accumulation. Pretreating aircraft with Type IV fluid is sometimes used
when ice is in the forecast and an aircraft is expected to remain on the ground for an extended
period of time. This type of anti-icing treatment can reduce the amount of deicing fluid needed
for an aircraft by reducing the amount of ice that forms on the aircraft.
7.5 References
Becher-Hoppe Associates, Inc. 2004. Airport Facilities - Rhinelander - Oneida County Airport.
(December 6). DCN AD00097.
CASQA. 2003. Vegetated Swale. (January 1). California Stormwater Quality Association, Menlo
Park, CA. DCN AD01137.
ERG. 2004. Aircraft Deicing using an Infrared System called Ice-Cat. (December 13). DCN
AD00095.
ERG. 2005. Memorandum from Steve Strackbein (ERG) to Project File: Summary of Weather
Support to Deicing Decision Making (WSDDM). A Winter Weather Now casting System. (January
3). DCN AD00185.
ERG. 2007. Memorandum from Juliana Stroup and Mary Willett (ERG) to Brian D'Amico (U.S.
EPA). Aircraft Deicing Stormwater Control Technologies and Their Removal Efficiencies.
(December 17). DCN AD00855.
FAA. 2005. Federal Aviation Administration Advisory Circular 120-89. "Ground De-Icing using
Infrared Energy. (December 13). DCN AD01139.
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FAA. 2007. Federal Aviation Administration Advisory Circular No. 150/5200-33B. "Hazardous
Wildlife Attractants on or Near Airports." (August 28). DCN AD01138.
Icewolf. The Evolution of Aircraft Deicing Systems, Icewolf Product Flyer. DCN AD00096.
IDS. 2006. Deicing the IDS Way, Product Flyer. (January 4). DCN D00077.
Jungo Engineering Ltd. 2005. Disposal of De-icing Effluent by Irrigation. (June 6-8). DCN
AD01200.
Rhode Island Airport Corporation. 2011. RIDEMandRIAC Reach Agreement. (December 21).
www.dem.ri.gov/programs/benviron/water/permits/ripdes/pdfs/riacprelim.pdf. DCN AD01286.
US Department of Defense. 2003. ESTCP, Mineralization of TNT, RDX, and By-Products in an
Anaerobic Granular Activated Carbon Fluidized Bed Reactor, (April). DCN AD00898.
USEPA. 1999. Final Engineering Site Visit Report for Greater Rockford International Airport.
U.S. Environmental Protection Agency. Washington, D.C. DCN T10402.
USEPA. 2006. Final Engineering Site Visit Report for Pittsburgh International Airport. U.S.
Environmental Protection Agency. Washington, D.C. (November 1). DCN AD00774.
USEPA. 2007a. Final Engineering Site Visit Report for Seattle - Tacoma International Airport.
U.S. Environmental Protection Agency. Washington, D.C. (July 1). DCN AD00778.
USEPA. 2007b. Final Engineering Site Visit Report for Denver International Airport. U.S.
Environmental Protection Agency. Washington, D.C. (November 4). DCN AD00779.
USEPA. 2008a. Final Engineering Site Visit Report for Minneapolis-St. Paul International
Airport. U.S. Environmental Protection Agency. Washington, D.C. (January 24). DCN
AD00793.
USEPA. 2008b. Final Engineering Site Visit Report for Salt Lake City International Airport.
U.S. Environmental Protection Agency. Washington, D.C. (January 24). DCN AD00792.
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Section 8 - Performance of Control and Treatment Scenarios
8. Performance of Control and Treatment Scenarios
EPA evaluated the performance of the selected control and treatment scenarios based on
their ability to collect and treat ADF-contaminated stormwater and/or their ability to reduce
pollutant loadings. EPA used airport-specific estimates of Type I and IV ADF to calculate the
volumes of applied and available ADF at each of these airports (ERG, 201 la). EPA then
evaluated the collection ranges of both the data collected by EPA and the data available in the
Transportation Research Board (TRB) manual (TRB Airport Cooperative Research Program,
2009), combined with best engineering judgment to estimate the collection efficiency of each of
the technologies below.
8.1 Deicing Pad Collection
EPA reviewed data on the performance of centralized deicing pads from a number of
larger airports across the United States and Europe including DEN, DAY, PHL, CVG, DTW,
PIT, and Oslo. These airports reported a collection range from 42 to 90 percent of their spent
and/or applied ADF.
Additionally, the TRB Airport Cooperative Research Program Report No. 14, Deicing
Planning Guidelines and Practices for Stormwater Management Systems, detailed airport
collection efficiencies ranging from 44 to 86 percent of applied glycol (TRB Airport Cooperative
Research Program, 2009).
EPA reviewed the airport-specific ADF usage data and determined that the collection of
42 to 90 percent of spent and/or applied ADF is equivalent to 61 to 90 percent of available ADF
(ERG, 201 lb). At proposal of this rule, EPA estimated the collection efficiency of deicing pads
to be 60 percent. Based on the Agency's new analysis, this estimate represents the lower range of
collection efficiency. As a result, EPA estimates deicing pads will collect at least 60 percent of
the available ADF.
8.2 Plug and Pump Collection with GCV
EPA reviewed performance data from General Mitchell International (MKE) airport
because its collection system matches the plug and pump with GCV collection system EPA
costed for this rule. MKE reported a collection range between 22.5 and 33 percent of applied
ADF.
Additionally, the TRB Airport Cooperative Research Program Report No. 14 reported
collection efficiencies between 20 and 35 percent of applied ADF for plug and pump systems
(TRB Airport Cooperative Research Program, 2009).
At proposal, EPA estimated a plug and pump with GCV collection system would collect
40 percent of available ADF. When adjusted for rounding, the mean of the data above is
approximately 40 percent. As such, EPA has determined that a well-operated plug and pump
system (in conjunction with GCVs) should be able to collect 40 percent of the available ADF.
DCN AD01270 contains further details on these calculations.
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8.3 GCV Collection
EPA did not identify nor did commenters provide collection efficiency data on GCVs
alone. Gerald R. Ford International airport, which uses two tow-behind glycol collection units in
conjunction with catch basin inserts to collect aircraft deicing contaminated stormwater around
the terminal gates and apron, reported collecting 29 percent of all applied glycol during the
2005/2006 deicing season. Mass balance data on glycol usage and collection at Theodore Francis
Green State airport between 2002 and 2006 indicate that its GCV-based system annually collects
between 26 and 48 percent of all applied glycol. Overall, collection efficiencies of applied glycol
from these airports ranged from 26 to 48 percent, although these systems also used some
combination of catch basin inserts, plug and pump technology, and/or apron systems.
EPA's data points are similar to those summarized in the TRB Airport Cooperative
Research Program Report No. 14. The report described collection efficiencies between 23 to 48
percent for glycol collection vehicles (TRB Airport Cooperative Research Program, 2009),
although these systems, like those EPA referenced, also used some combination of catch basin
inserts, plug and pump technology, and/or apron systems.
The ranges presented in the literature provide higher collection efficiencies than those
associated with a plug and pump system; however, all of these data points include technologies
that would have higher collection efficiencies than a GCV alone. While EPA is unable to
document the efficiency of a GCV alone, it stands to reason that the collection efficiency of a
GCV alone would be less than that of a plug and pump with a GCV. For the purposes of today's
regulation, on a national basis, EPA assumes that a GCV is able to achieve approximately half
the collection of a plug and pump with a GCV, or 20 percent of the available ADF.
8.4 AFB Treatment Performance
EPA collected data on the effectiveness of AFB treatment systems through literature
review, its own sampling efforts, and industry-supplied data. These systems have demonstrated
effective treatment for targeted pollutants, including COD, BOD5, and glycol. Based on EPA's
sampling data from Albany International airport, COD was reduced by greater than 97 percent,
BOD5 was reduced by greater than 98 percent, and glycol was reduced by greater than 99 percent
(ERG, 2007).
Influent COD concentrations that can be efficiently treated by an AFB system range from
approximately 2,000 to 128,000 mg/L and an AFB system can manage brief excursions outside
of this range. (See Airport Council International - North America comments on EPA's Proposed
Rule for Effluent Guidelines for the Airport Deicing Category). EPA selected AFB as the best
technology for on-site treatment of ADF-contaminated stormwater because of the technology's
superior ability to destroy the pollutants of concern and to handle a range of influent
concentrations. An evaluation of AFB treatment for other industrial wastewaters that have high
COD content, such as distillery, textile, dairy, and brewery wastewaters, shows COD removals in
the 50 to 98 percent range (ERG, 2010).
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8.5 References
ERG. 2007. Memorandum from Juliana Stroup and Mary Willett (ERG) to Brian D'Amico (U.S.
EPA). Aircraft Deicing Stormwater Control Technologies and Their Removal Efficiencies.
(December 17). DCN AD00855.
ERG. 2010. Memorandum from Cortney Itle (ERG) to Brian D'Amico (U.S. EPA). Summary of
Anaerobic Fluidized Bed Applications. (August 31). DCN ADO 1262.
ERG. 201 la. Memorandum from Cortney Itle and Mary Willett (ERG) to Brian D'Amico (U.S.
EPA). ADF Collection and Control Efficiency Review. (June 15). DCN ADO 1270.
ERG.201 lb. Memorandum from Steve Strackbein and Mary Willett (ERG) to Brian D'Amico
(U.S. EPA). Centralized Deicing Pad ADF Collection Efficiency. (July 12). AD01271.
TRB Airport Cooperative Research Program. 2009. Deicing Planning Guidelines and Practices
for Stormwater Management Systems ACRP Report No. 14. DCN AD01191.
Williams, M. 2006. Baltimore-Washington International Airport Deicing Mass Balance.
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Section 9 - Pollutant Loadings and Pollutant Load Reduction Estimates
9. Pollutant Loadings and Pollutant Load Reduction Estimates
Pollutant loadings from airport deicing operations are highly variable and airport-
specific. Because the use of deicing and anti-icing chemicals is weather-dependent, the pollutant
loadings at each airport vary from year to year based on weather conditions and also based on
each airport's climate. In addition, the amount of applied chemical that is discharged to surface
water depends on the existing stormwater separation, collection, and/or containment system
present at each airport.
Due to the variations of the pollutant discharges, EPA determined that it would not be
appropriate to develop baseline pollutant loadings using end-of-pipe monitoring data. Monitoring
data on an airport's deicing stormwater outfall(s) provides only a "snap shot" of a single point in
time, during a monthly monitoring event or, in some cases, a single storm event. In addition,
these data are available only for a select number of airports and are airport-specific. Although
these data provide information on the types of pollutants present in airport deicing stormwater
and the range of concentrations that may reach outfall points, there is insufficient basis for
extrapolating or transferring the data across large time frames (e.g., an entire winter season) or to
other airports.
Therefore, EPA developed a pollutant loading estimation methodology for individual
airports based on the use of ADF and airfield chemicals at the airports surveyed by EPA. The
methodology takes into account EPA's existing data sources and provides a better estimate of the
loadings than those based on sporadic monitoring data alone. The Agency used a model-site
approach to estimate loads for the Airport Deicing Category. A model airport is an operating
airport whose deicing chemical usage and unit operation and treatment information were used as
parameters for the loadings model. EPA selected an airport-by-airport approach to estimate
baseline loadings and loading removals from the model airports, as opposed to a more
generalized approach, to better characterize the current control and treatment systems in place for
ADF-contaminated stormwater and to account for current site conditions and airport operations.
This section discusses the data sources available to EPA to support its pollutant loadings
and loading reduction estimates (Section 9.1), provides an overview of EPA's pollutant loading
methodology (Section 9.2), and describes the calculation steps that compose EPA's loading
methodology (Sections 9.3 through 9.6). Section 9.7 summarizes EPA's approach for estimating
loading reductions associated with the discontinued use of urea as an airfield deicing chemical.
9.1 Data Sources
EPA considered the following available data when developing the pollutant loadings
estimation methodology for airport deicing operations (see Section 3 for more information about
the data sources):
Pavement deicing chemical usage information for the 2002/2003, 2003/2004, and
2004/2005 deicing seasons, as reported by airport personnel in the airport
questionnaire;
ADF purchase information for the 2002/2003, 2003/2004, and 2004/2005 deicing
seasons, as reported by airline personnel in the airline detailed questionnaire;
Standard airport information available from the FAA, including the number of
operations and departures by airport;
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Weather information for each airport from the National Oceanic and Atmospheric
Administration (NOAA), including temperature, freezing precipitation, and
snowfall data;
Existing airport stormwater collection and containment systems, as reported by
airport personnel in the airport questionnaire or during EPA site visits;
Standard chemical information about ADF and pavement deicing chemicals,
including molecular formulas and densities; and
Analytical data from EPA sampling episodes of airport deicing operations.
9.2 Aircraft Deicing Pollutant Loading
This section presents EPA's methodology for estimating ADF pollutant loads using
airline questionnaire data on ADF usage and the theoretical oxygen demand associated with
various deicing fluids.
9.2.1 Estimate the Amount of Applied Deicing Chemical
EPA requested the purchase amount, concentration, and brand name in the airline
detailed questionnaire for the 2002/2003, 2003/2004, and 2004/2005 deicing seasons for the
following ADF chemicals:
EG Type I;
EG Type II;
EG Type IV;
PG Type I;
PG Type II;
PG Type III;
PG Type IV; and
Isopropyl Alcohol-Based Fluid.
Questionnaire responses provided sufficient data to estimate ADF usage at 56 model
airports. In some cases, data were not available for every airline operating at a model airport. In
these instances, EPA extrapolated the amount of ADF used at the reporting airlines to estimate
the total amount of ADF used by the entire airport, based on the number of airport operations
(departures) at the reporting airlines and the total amount of airport operations. Table 9-1
presents the ADF estimates based on airline questionnaire responses. No airports reported
purchasing EG Type II, EG Type III, PG Type II, PG Type III, or isopropyl alcohol-based fluid.
In addition to the ADF data reported in the airline detailed questionnaire, 10 airports
reported their estimates of total annual ADF usage to EPA in the comment section of the airport
questionnaire (see Table 9-2). These ADF data were combined with the ADF data reported in the
airline detailed questionnaires, resulting in 66 airports with total PG/EG (gallons) usage
estimates. EPA used the airport's estimate of ADF usage from the airport questionnaires because
those data came from a certified questionnaire response.
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Table 9-1. ADF Estimates Based on Airline Detailed Questionnaire Responses
Airport
ID
Airport Name
Estimated
PG/EG Use
(GPY)
PG
Type I
(%)
PG
Type IV
(%)
EG
Type 1
(%)
EG
Tvpe IV
(%)
1003
Ketchikan International
18,182
0
0
100
0
1006
Chicago O'Hare International
1,516,626
80
20
0
0
1010
Fairbanks International
83,335
0
0
100
0
1011
Lambert - St Louis International
325,122
23
1
70
6
1012
Ted Stevens Anchorage International
420,735
0
0
100
0
1013
Wiley Post-Will Rogers Mem
3,056
9
0
91
0
1021
Buffalo Niagara International
281,836
92
9
0
0
1022
Fort Wayne International
50,412
92
8
0
0
1024
Indianapolis International
452,155
91
9
0
0
1026
Dallas/Fort Worth International
166,790
43
12
38
7
1028
Denver International
1,043,138
87
10
4
0
1029
La Guardia
485,157
75
22
2
1
1036
Baltimore - Washington
International
323,623
90
10
0
0
1037
George Bush Intercontinental
Airport/Houston
10,242
82
18
0
0
1043
Ralph Wien Memorial
2,500
27
0
73
0
1047
Sacramento Mather
1,282
100
0
0
0
1053
General Edward Lawrence Logan
International
995,249
82
17
0
0
1058
Gerald R Ford International
98,156
86
13
0
0
1059
Greater Rochester International
229,158
91
9
0
0
1065
Albany International
125,775
93
7
0
0
1066
Salt Lake City International
570,540
22
6
52
20
1069
Cleveland - Hopkins International
582,321
90
10
0
0
1074
South Bend Regional
29,586
75
25
0
0
1079
Manchester
177,307
87
13
0
0
1080
Syracuse Hancock International
186,351
97
3
0
0
1089
John F Kennedy International
560,031
82
18
0
0
1095
Chicago Midway International
293,834
88
12
0
0
1100
Toledo Express
46,449
64
5
29
2
1103
Juneau International
48,014
0
0
100
0
1104
Nome
3,047
15
0
85
0
1105
Spokane International
67,984
92
8
0
0
1107
Pittsburgh International
943,982
88
12
0
0
1109
Airborne Airpark
432,416
74
26
0
0
1110
Aniak
476
100
0
0
0
1111
Port Columbus International
288,374
92
8
0
0
1113
Cincinnati/Northern Kentucky
International
715,836
24
5
61
11
93
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Technical Development Document for Effluent
Limitation Guidelines and Standards for the Airport Deicing Category
Section 9 - Pollutant Loadings and Pollutant Load Reduction Estimates
Table 9-1 (Continued)
Airport
ID
Airport Name
Estimated
PG/EG Use
(GPY)
PG
Type I
(%)
PG
Type IV
(%)
EG
Type 1
(%)
EG
Tvpe IV
(%)
1117
Cherry Capital
11,524
75
0
0
25
1118
Bethel
4,897
40
0
60
0
1123
James M Cox Dayton International
90,580
89
11
0
0
1124
Des Moines International
79,658
84
14
3
0
1126
Minneapolis/ St Paul
International/Wold - Chamberlain
1,456,537
93
7
0
0
1128
Charlotte/Douglas International
143,572
81
19
0
0
1129
Bradley International
427,068
88
12
0
0
1136
General Mitchell International
152,944
90
9
0
1
1138
Detroit Metropolitan Wayne County
2,152,292
93
7
0
0
1139
Philadelphia International
979,983
88
12
0
0
1140
Memphis International
199,174
88
12
0
0
1141
Ronald Reagan Washington National
219,533
81
16
3
0
1142
Washington Dulles International
1,076,083
77
22
1
0
1145
Newark Liberty International
1,123,057
86
14
0
0
1148
Kansas City International
203,726
75
8
17
0
1149
Fort Worth Alliance
1,522
97
3
0
0
1150
Greater Rockford
146,856
79
21
0
0
1151
Kalamazoo/Battle Creek
International
22,002
84
16
0
0
1152
Duluth International
68,168
96
4
0
0
1153
Akron - Canton Regional
60,246
90
10
0
0
Source: Airport Deicing Operations ADF Usage Database (USEPA, 2008).
Note: PG/EG gallons represent total usage normalized to 100 percent glycol. Values may not sum to 100 due to
rounding.
GPY - Gallons per year.
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Technical Development Document for Effluent
Limitation Guidelines and Standards for the Airport Deicing Category
Section 9 - Pollutant Loadings and Pollutant Load Reduction Estimates
Table 9-2. ADF Data Reported in the Airport Questionnaire
Airport ID
Airport Name
PG/EG Usage (GPY)
1115
Jacksonville International
1,000
1062
Birmingham International
5,000
1072
Gillette-Campbell County
880
1060
Williamson County Regional
150
1096
Santa Fe Municipal
1,108
1097
Lovell Field
4,148
1025
Tupelo Regional
820
1143
San Francisco International
105
1001
Montgomery Regional (Dannelly Field)
232
1019
Ontario International
35
Source: Airport Deicing Operations ADF Usage Database (USEPA, 2008).
GPY - Gallons per year.
Using the airline and airport questionnaire data on ADF purchases, airport departures,
and climate, EPA correlated the estimate of the amount of ADF used to the climate and size of
each airport. EPA created an "ADF Factor" to estimate the relative amount of deicing occurring
at each airport based on the airport's climate and number of departures. EPA calculated the ADF
Factor by multiplying the 30-year annual average number of SOFP days by the average number
of annual departures at each airport during 2004-2006 (USEPA, 2008a). EPA graphed the total
gallons of PG/EG purchased with the ADF factor and determined the equation of the line. During
this analysis, EPA noted a difference in the relationship of ADF Factor and ADF usage for
Alaskan airports compared to other airports. Due to this difference, EPA developed a separate
graph and equation for Alaskan airports. Figure 9-1 shows the graph for non-Alaskan airports
and Figure 9-2 presents the graph for Alaskan airports.
2,500,000
y = 0.3073x
R2 = 0.7622
2,000,000
PG/EG
Gallons 1 500,000
per Year
1,000,000
500,000
0
2,000,000
4,000,000
6,000,000
8,000,000
ADF Factor (SOFP Days x Average Annual Departures)
Figure 9-1. ADF Factor vs. PG/EG Gallons for U.S. Airports (excluding Alaska)
95
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Technical Development Document for Effluent
Limitation Guidelines and Standards for the Airport Deicing Category
Section 9 - Pollutant Loadings and Pollutant Load Reduction Estimates
500,000
y = 0.0632X
R2 = 0.7031
400,000
PG/EG
Gallons
Per Year
300,000
200,000
100,000
2,000,000
4,000,000
6,000,000
0
ADF Factor (SOFP Days x Average Annual Departures)
Figure 9-2. ADF Factor vs. PG/EG Gallons for Alaskan Airports
EPA used the line equations to estimate the total gallons of ADF used at model airports
that did not have available ADF data in the airport or airline detailed questionnaires. Based on
the estimated total gallons of ADF used at an airport, EPA calculated the distribution of different
types of ADF (PG/EG, Type I/Type IV) based on the average percent distribution of the reported
ADF amounts. See thq Airport Deicing Loadings Calculations memorandum (ERG, 2008b) for
more detail. Table 9-3 presents the final estimates of ADF usage for airports in the scope of the
final rule.
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Technical Development Document for Effluent
Limitation Guidelines and Standards for the Airport Deicing Category
Section 9 - Pollutant Loadings and Pollutant Load Reduction Estimates
Table 9-3. ADF Annual Usage Estimates for In-scope Airports
Airport
ID
Airport Name
PG Type I
(gallons)
PG Type IV
(gallons)
EG Type I
(gallons)
EG Type IV
(gallons)
1001
Montgomery Regional (Dannelly Field)
166
22
41
3
1003
Ketchikan International
0
0
18,182
0
1004
Norfolk International
22,084
2,938
5,451
402
1006
Chicago O'Hare International
1,213,301
303,325
0
0
1007
Yeager
35,450
4,715
8,750
646
1008
Tucson International
1,675
223
413
31
1010
Fairbanks International
0
0
83,335
0
1011
Lambert-St Louis International
74,778
3,251
227,586
19,507
1012
Ted Stevens Anchorage International
0
0
420,735
0
1014
Albuquerque International Sunport
46,107
6,133
11,380
840
1015
Gulfport-Biloxi International
1,109
148
274
20
1017
Austin Straubel International
44,442
5,912
10,969
810
1018
Piedmont Triad International
49,169
6,540
12,136
896
1019
Ontario International
25
3
6
0
1020
Hartsfield - Jackson Atlanta
International
259,100
34,465
63,950
4,720
1021
Buffalo Niagara International
259,289
25,365
0
0
1022
Fort Wayne International
46,379
4,033
0
0
1023
Seattle-Tacoma International
112,631
14,982
27,799
2,052
1024
Indianapolis International
411,461
40,694
0
0
1026
Dallas/Fort Worth International
71,720
20,015
63,380
11,675
1028
Denver International
907,530
104,314
41,726
0
1029
La Guardia
363,868
106,735
9,703
4,852
1031
Richmond International
42,442
5,646
10,476
773
1032
Austin-Bergstrom International
17,198
2,288
4,245
313
1033
Mc Carran International
7,613
1,013
1,879
139
1034
Metropolitan Oakland International
0
0
0
0
1035
San Diego International
0
0
0
0
1036
Baltimore-Washington International
291,261
32,362
0
0
1037
George Bush Intercontinental
Airport/Houston
8,399
1,844
0
0
1040
Louis Armstrong New Orleans
International
0
0
0
0
1041
Glacier Park International
27,578
3,668
6,807
502
1043
Ralph Wien Memorial
675
0
1,825
0
1044
Roanoke Regional/Woodrum Field
23,552
3,133
5,813
429
1045
Norman Y. Mineta San Jose
International
10
0
0
0
1046
Long Island Mac Arthur
31,135
4,141
7,685
567
1050
Aspen-Pitkin Co/Sardy Field
10,742
1,429
2,651
196
1052
Wilmington International
1,556
207
384
28
97
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Technical Development Document for Effluent
Limitation Guidelines and Standards for the Airport Deicing Category
Section 9 - Pollutant Loadings and Pollutant Load Reduction Estimates
Table 9-3 (Continued)
Airport
ID
Airport Name
PG Type I
(gallons)
PG Type IV
(gallons)
EG Type I
(gallons)
EG Type IV
(gallons)
1053
General Edward Lawrence Logan
International
816,104
169,192
0
0
1054
Jackson Hole
24,413
3,247
6,026
445
1057
Will Rogers World
35,409
4,710
8,740
645
1058
Gerald R. Ford International
84,414
12,760
0
0
1059
Greater Rochester International
208,534
20,624
0
0
1061
William P Hobby
10,134
1,348
2,501
185
1062
Birmingham International
3,578
476
883
65
1063
Evansville Regional
14,412
1,917
3,557
263
1065
Albany International
116,971
8,804
0
0
1066
Salt Lake City International
125,519
34,232
296,681
114,108
1067
Helena Regional
13,147
1,749
3,245
240
1068
Eppley Airfield
79,386
10,560
19,594
1,446
1069
Cleveland-Hopkins International
524,089
58,232
0
0
1070
City of Colorado Springs Municipal
54,230
7,214
13,385
988
1074
South Bend Regional
22,189
7,396
0
0
1075
Pensacola Regional
592
79
146
11
1078
Nashville International
65,479
8,710
16,161
1,193
1079
Manchester
154,257
23,050
0
0
1080
Syracuse Hancock International
180,760
5,591
0
0
1081
Bob Hope
0
0
0
0
1083
Tampa International
0
0
0
0
1084
Bismarck Municipal
15,018
1,998
3,707
274
1086
Palm Beach International
732
97
181
13
1087
El Paso International
11,608
1,544
2,865
211
1088
Outagamie County Regional
41,375
5,504
10,212
754
1089
John F Kennedy International
459,225
100,806
0
0
1090
Boise Air Terminal/Gowen Fid
51,086
6,795
12,609
931
1091
Rochester International
24,717
3,288
6,101
450
1094
Boeing Field/King County International
3,688
491
910
67
1095
Chicago Midway International
258,574
35,260
0
0
1097
Lovell Field
2,968
395
733
54
1099
Sacramento International
0
0
0
0
1100
Toledo Express
29,728
2,322
13,470
929
1101
Portland International
80,173
10,664
19,788
1,461
1102
John Wayne Airport-Orange County
0
0
0
0
1103
Juneau International
0
0
48,014
0
1104
Nome
457
0
2,590
0
1105
Spokane International
62,545
5,439
0
0
98
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Technical Development Document for Effluent
Limitation Guidelines and Standards for the Airport Deicing Category
Section 9 - Pollutant Loadings and Pollutant Load Reduction Estimates
Table 9-3 (Continued)
Airport
ID
Airport Name
PG Type I
(gallons)
PG Type IV
(gallons)
EG Type I
(gallons)
EG Type IV
(gallons)
1107
Pittsburgh International
830,704
113,278
0
0
1108
Louisville International-Standiford Field
91,849
12,217
22,670
1,673
1111
Port Columbus International
265,304
23,070
0
0
1113
Cincinnati/Northern Kentucky
International
171,801
35,792
436,660
78,742
1114
Stewart International
23,086
3,071
5,698
421
1115
Jacksonville International
716
95
177
13
1116
Reno/Tahoe International
53,382
7,101
13,176
973
1117
Cherry Capital
8,643
0
0
2,881
1118
Bethel
1,959
0
2,938
0
1119
Rickenbacker International
7,661
1,019
1,891
140
1120
Rapid City Regional
18,185
2,419
4,488
331
1121
Theodore Francis Green State
107,383
14,284
26,504
1,956
1122
Southwest Florida International
680
90
168
12
1123
James M Cox Dayton International
80,616
9,964
0
0
1124
Des Moines International
66,913
11,152
2,390
0
1126
Minneapolis/St Paul International/Wold-
Chamberlain
1,354,580
101,958
0
0
1128
Charlotte/Douglas International
116,293
27,279
0
0
1129
Bradley International
375,820
51,248
0
0
1130
San Antonio International
9,119
1,213
2,251
166
1131
Wilkes-Barre/Scranton International
30,426
4,047
7,510
554
1133
Phoenix Sky Harbor International
0
0
0
0
1135
Lafayette Regional
1,065
142
263
19
1136
General Mitchell International
137,650
13,765
0
1,529
1137
Dallas Love Field
26,622
3,541
6,571
485
1138
Detroit Metropolitan Wayne County
2,001,632
150,660
0
0
1139
Philadelphia International
862,385
117,598
0
0
1140
Memphis International
175,273
23,901
0
0
1141
Ronald Reagan Washington National
177,822
35,125
6,586
0
1142
Washington Dulles International
828,584
236,738
10,761
0
1143
San Francisco International
75
10
19
1
1144
Central Wisconsin
31,203
4,151
7,702
568
1145
Newark Liberty International
965,829
157,228
0
0
1146
Northwest Arkansas Regional
22,013
2,928
5,433
401
1147
Raleigh-Durham International
73,281
9,748
18,087
1,335
1148
Kansas City International
152,794
16,298
34,633
0
Source: Airport Deicing Operations ADF Usage Database (USEPA, 2008).
Note: Values may not sum to total usage amounts due to rounding.
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Limitation Guidelines and Standards for the Airport Deicing Category
Section 9 - Pollutant Loadings and Pollutant Load Reduction Estimates
9.2.2 Calculate the Amount of Pollutant Load Associated with the Applied ADF
As aircraft deicing chemicals break down in the environment, they increase COD and
BOD. EPA calculated the amount of COD and BOD (presented as-5 day BOD, or BOD5)
associated with the degradation of the applied deicing/anti-icing chemicals.
EPA considered two approaches to estimate the amount of COD and BOD5 associated
with deicing chemicals. The first approach involved using laboratory empirical COD and BOD5
data for deicing chemicals. The second approach involved using standard chemical information
and stoichiometric equations to estimate COD and BOD5 for each chemical.
EPA determined it would not be suitable to use empirical data to estimate loadings for
three main reasons. First, empirical COD and BOD5 data were not readily available for all
deicing/anti-icing chemicals. Second, the available empirical data were outdated and brand-
specific. Finally, chemical formulations vary significantly over time and by brand, so it is
inappropriate to apply any given set of empirical data to all airports and chemicals.
EPA selected the second approach, calculating loadings based on standard chemical
information and stoichiometric equations. The advantage of this methodology over using
empirical data is that it can be used for all deicing chemicals. In addition, this methodology
allows the calculations and assumptions used to be clearly presented. EPA checked the validity
of the COD and BOD5 concentrations for PG and EG calculated using this methodology against
the available empirical data and found a good match.
Calculate the Total Mass of Each Pollutant
First, EPA estimated the total mass of each chemical based on the airline and airport
questionnaire responses (which specified varying formulations of ADF and deicing products). To
calculate the total mass of applied chemical, EPA multiplied the reported mass of each chemical
by the reported percentage of the pollutant in the ADF formulation, by the density of the
pollutant.
Determine the Theoretical Oxygen Demand of Each Chemical
Next, EPA determined the theoretical oxygen demand (ThOD) associated with the
degradation of each of the deicing chemicals. The ThOD estimate was based on the molecular
formula of the chemical and the stoichiometric equation of the breakdown of the chemical to the
end products of carbon dioxide and water. Table 9-4 lists the calculated ThOD for each chemical
in aircraft deicers.
Table 9-4. Theoretical Oxygen Demand Calculations for Aircraft Deicing Chemicals
Deicing Compound
Molecular
Formula
Stoichiometric Formula
ThOD (Moles ofO,
per Mole of Deicing
Compound)
PG
C3H8C>2
C3H802 + 4 02 -> 3 C02 + 4 H20
4.0
EG
c2h6o2
2[C2H602] + 5 02 -> 4 C02 + 6 H20
2.5
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Section 9 - Pollutant Loadings and Pollutant Load Reduction Estimates
Determine the COD of Each Chemical
EPA next determined the COD loading associated with the chemical's degradation. EPA
assumed that the chemical would completely degrade in the environment over time and therefore
the calculated ThOD load would be equivalent to the COD load. EPA estimated the COD load
associated with each reported chemical based on the calculated mass of the chemical purchased,
the molecular weight of the chemical, the ThOD, and the molecular weight of oxygen, using the
equation below:
w . s w , s 434 grams moles of chemical
COD Load (pounds) = Chemical (pounds) x x Chemical Molecular Weight
pound I grams of chemical
rT,, ( moles of O2 1 ^ , , T . , (grams of O2 ] pound
x ThOD x O2 Molecular Weight x
^ moles of chemical) \ moles of O2) 434 grams
Determine the BOD5 of Each Chemical
EPA calculated the BOD5 loading of ADF based on the estimated COD loading in ADF.
EPA developed an industry-specific relationship between COD and BOD5 using analytical data
for untreated deicing stormwater from the EPA sampling episodes at Albany International
airport, Pittsburgh International airport, and Denver International airport. The average
COD/BOD5 ratio was 1.67. This relationship was used to calculate the BOD5 associated with the
degradation of the deicing chemical. See thq Airport Deicing Loading Calculations
memorandum (ERG, 2008b) for more information.
9.2.3 Estimate the Amount of Baseline Pollutant Load that is Discharged Directly
The amount of applied chemical that is discharged directly is airport-specific and
dependent upon the existing stormwater collection/treatment system present at each airport.
Typically, ADF is applied at a number of specific locations at the airport, including gates,
deicing pads, and/or aprons.
In estimating the direct discharge amount of ADF, EPA first estimated the amount of
applied ADF that would be available for discharge. EPA assumed that 75 percent of applied
Type I ADF falls onto the pavement at the deicing area and is available for discharge; the
remaining 25 percent is lost to evaporation, wind, or tire tracking, or adheres to the plane and is
later sheared off during taxiing and takeoff (Switzenbaum, et al., 1999). EPA assumed that 10
percent of Type IV ADF falls to the pavement in the deicing area and is available for discharge;
the remaining 90 percent adheres to the plane. The Agency multiplied the total amount of applied
ADF by the appropriate percentage available for discharge to determine the amount of ADF that
is available for discharge.
Next, EPA determined the percentage of available ADF that would be directly discharged
at each airport, depending on the airport's current control and treatment systems (ERG, 2011).
EPA estimated collection and control percentages of available ADF for each airport based on
information provided during EPA site visits and in the airport questionnaire. If the airport did not
provide an ADF collection and control percentage estimate, EPA personnel reviewed the
airport's questionnaire responses and the reported collection and control percentage of similar
systems to determine an estimate for the airport.
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Section 9 - Pollutant Loadings and Pollutant Load Reduction Estimates
The COD load associated with each ADF chemical applied at an airport was reduced by
EPA's estimate of the airport's current collection and control percentage to estimate the amount
of COD directly discharged. These estimates represent the baseline amount of ADF discharged
to the environment. Table 9-5 in Section 9.2.5 presents EPA's estimate of the baseline COD load
(in pounds) directly discharged by each airport.
9.2.4 Estimate Pollutant Loading Discharges for Each ADF Collection/Control
Scenario
Two of EPA's regulatory options require a specific collection and treatment percentage
of available ADF. For the final rule, EPA evaluated the following scenarios as discussed in
Section 11:
20% Collection and Control Scenario: collection and treatment of 20 percent of
available ADF; and
40% Collection and Control Scenario: collection and treatment of 40 percent of
available ADF.
EPA estimated the direct discharge COD load of each collection and control scenario
accounting for the following two components:
The COD load associated with the applied ADF, minus any reductions achieved
by the collection and control practices implemented; and
The COD load that would be discharged from AFB biological treatment of the
collected treatment.
EPA estimated the amount of COD load that would be discharged from treatment for
each airport that had load reductions in a scenario. Using analytical data from its sampling
episodes, EPA determined that AFB systems remove 97.5 percent of COD. Therefore, EPA
assumed that 97.5 percent of the COD load going to treatment would be removed and 2.5 percent
would be discharged.
9.2.5 Estimate Pollutant Loading Reductions for Each ADF Collection/Control
Scenario
After estimating the loads for each scenario, EPA estimated the loading reductions as
compared to baseline. Table 9-5 lists the ADF COD baseline loads and reductions for each
control and treatment scenario EPA evaluated for those airports in the scope of the final rule.
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Section 9 - Pollutant Loadings and Pollutant Load Reduction Estimates
Table 9-5. ADF COD Baseline Loads and Loading Reductions for Each Control and
Treatment Scenario, by In-Scope Airport
Airport
ID
Airport
Airport
Weighting
Factor
Current
ADF
Collection
(%)
Baseline
COD Load
(pounds)
COD Load
Reduction for
20% Collection
and Control
Scenario
(pounds)
COD Load
Reduction for
40% Collection
and Control
Scenario
(pounds)
1001
Montgomery Regional
(Dannelly Field)
6.7013
0
2,214
432
863
1003
Ketchikan International
1.0000
NA
0
0
0
1004
Norfolk International
1.0000
20
235,637
0
57,436
1006
Chicago O'Hare International
1.0000
40
8,204,552
0
0
1007
Yeager
2.1508
40
283,685
0
0
1008
Tucson International
2.9997
20
17,873
0
4,357
1010
Fairbanks International
1.0000
>60
299,205
0
0
1011
Lambert-St Louis International
1.0000
>60
1,154,584
0
0
1012
Ted Stevens Anchorage
International
1.0000
40
2,265,902
0
0
1014
Albuquerque International
Sunport
1.0000
20
491,959
0
119,915
1015
Gulfport-Biloxi International
5.8413
>60
0
0
0
1017
Austin Straubel International
2.3269
40
355,646
0
0
1018
Piedmont Triad International
1.0000
0
655,787
127,879
255,757
1019
Ontario International
1.0000
0
334
200
200
1020
Hartsfield - Jackson Atlanta
International
1.0000
>60
1,382,287
0
0
1021
Buffalo Niagara International
1.0000
40
1,718,928
0
0
1022
Fort Wayne International
1.9682
0
511,705
102,341
204,682
1023*
Seattle-Tacoma International
1.0000
0
1,502,208
292,931
585,861
1024
Indianapolis International
1.0000
40
2,728,125
0
0
1026
Dallas/Fort Worth International
1.0000
>60
557,682
0
0
1028
Denver International
1.0000
>60
104,244
0
0
1029
La Guardia
1.0000
0
4,216,728
822,262
1,644,524
1031
Richmond International
1.0000
40
339,643
0
0
1032
Austin-Bergstrom International
1.0000
40
137,629
0
0
1033
Mc Carran International
1.0000
40
60,923
0
0
1034
Metropolitan Oakland
International
1.0000
>60
0
0
0
1035
San Diego International
1.0000
>60
0
0
0
1036
Baltimore-Washington
International
1.0000
>60
1,289,506
0
0
1037
George Bush Intercontinental
Airport/Houston
1.0000
40
56,571
0
0
1040
Louis Armstrong New Orleans
International
1.0000
>60
0
0
0
103
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Technical Development Document for Effluent
Limitation Guidelines and Standards for the Airport Deicing Category
Section 9 - Pollutant Loadings and Pollutant Load Reduction Estimates
Table 9-5 (Continued)
Airport
ID
Airport
Airport
Weighting
Factor
Current
ADF
Collection
(%)
Baseline
COD Load
(pounds)
COD Load
Reduction for
20% Collection
and Control
Scenario
(pounds)
COD Load
Reduction for
40% Collection
and Control
Scenario
(pounds)
1041
Glacier Park International
3.1409
0
367,815
71,724
143,448
1043
Ralph Wien Memorial
1.0000
0
23,743
4,630
9,260
1044
Roanoke RegionalAVoodrum
Field
2.1921
0
314,124
61,254
122,508
1045
Norman Y. Mineta San Jose
International
1.0000
10
0
0
0
1046
Long Island Mac Arthur
1.9985
>60
166,102
0
0
1050
Aspen-Pitkin Co/Sardy Field
4.7500
40
85,963
0
0
1052
Wilmington International
6.0388
0
20,756
4,047
8,095
1053
General Edward Lawrence
Logan International
1.0000
0
9,147,072
1,783,679
3,567,358
1054
Jackson Hole
4.3500
>60
0
0
0
1057
Will Rogers World
1.0000
0
472,260
92,091
184,181
1058
Gerald R. Ford International
1.5862
40
563,544
0
0
1059
Greater Rochester International
1.0000
50
1,152,208
0
0
1061
William P Hobby
1.0000
>60
0
0
0
1062
Birmingham International
2.8410
0
47,717
9,305
18,610
1063
Evansville Regional
5.1042
0
192,217
37,482
74,965
1065
Albany International
1.0000
>60
25,771
0
0
1066
Salt Lake City International
1.0000
>60
1,687,338
0
0
1067
Helena Regional
4.2000
>60
0
0
0
1068
Eppley Airfield
1.0000
0
1,058,801
206,466
412,933
1069
Cleveland-Hopkins
International
1.0000
40
3,480,467
0
0
1070
City of Colorado Springs
Municipal
1.7414
40
433,971
0
0
1074
South Bend Regional
2.1417
>60
0
0
0
1075
Pensacola Regional
3.9341
>60
0
0
0
1078
Nashville International
1.0000
>60
349,329
0
0
1079
Manchester
1.0000
0
1,715,962
334,613
669,225
1080
Syracuse Hancock International
1.0000
>60
791,854
0
0
1081
Bob Hope
1.0000
>60
0
0
0
1083
Tampa International
1.0000
>60
0
0
0
1084
Bismarck Municipal
3.8679
0
200,305
39,059
78,119
1086
Palm Beach International
1.0000
>60
0
0
0
1087
El Paso International
3.0457
>60
0
0
0
1088
Outagamie County Regional
2.4841
0
551,842
107,609
215,218
104
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Technical Development Document for Effluent
Limitation Guidelines and Standards for the Airport Deicing Category
Section 9 - Pollutant Loadings and Pollutant Load Reduction Estimates
Table 9-5 (Continued)
Airport
ID
Airport
Airport
Weighting
Factor
Current
ADF
Collection
(%)
Baseline
COD Load
(pounds)
COD Load
Reduction for
20% Collection
and Control
Scenario
(pounds)
COD Load
Reduction for
40% Collection
and Control
Scenario
(pounds)
1089
John F Kennedy International
1.0000
0
5,155,239
1,005,272
2,010,543
1090
Boise Air Terminal/Gowen Fid
1.5043
>60
272,543
0
0
1091
Rochester International
3.1749
40
197,799
0
0
1094
Boeing Field/King County
International
5.8985
40
29,510
0
0
1095
Chicago Midway International
1.0000
>60
0
0
0
1097
Lovell Field
4.9996
0
39,586
23,752
23,752
1099
Sacramento International
1.0000
20
0
0
0
1100
Toledo Express
2.0917
20
359,704
0
87,678
1101
Portland International
1.0000
20
855,437
0
208,513
1102
John Wayne Airport-Orange
County
1.0000
>60
0
0
0
1103
Juneau International
1.0000
0
430,969
84,039
168,078
1104
Nome
1.0000
0
28,231
5,505
11,010
1105
Spokane International
1.5192
>60
0
0
0
1107
Pittsburgh International
1.0000
>60
3,689,998
0
0
1108
Louisville International-
Standiford Field
1.0000
>60
490,009
0
0
1111
Port Columbus International
1.0000
0
2,927,149
570,794
1,141,588
1113
Cincinnati/Northern Kentucky
International
1.0000
>60
415,766
0
0
1114
Stewart International
2.8661
40
184,745
0
0
1115
Jacksonville International
1.0000
>60
0
0
0
1116
Reno/Tahoe International
1.0000
20
569,580
0
138,835
1117
Cherry Capital
3.5400
>60
0
0
0
1118
Bethel
1.0000
0
47,733
9,308
18,616
1119
Rickenbacker International
4.3659
0
102,180
19,925
39,850
1120
Rapid City Regional
3.1082
0
242,540
47,295
94,591
1121
Theodore Francis Green State
1.0000
>60
572,884
0
0
1122
Southwest Florida International
1.0000
>60
0
0
0
1123
James M Cox Dayton
International
1.0000
>60
357,499
0
0
1124
Des Moines International
1.6211
40
460,483
0
0
1126
Minneapolis/St Paul
InternationalAV old-
Chamberlain
1.0000
>60
5,968,923
0
0
1128
Charlotte/Douglas International
1.0000
0
1,308,047
255,069
510,138
1129
Bradley International
1.0000
>60
1,669,398
0
0
105
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Technical Development Document for Effluent
Limitation Guidelines and Standards for the Airport Deicing Category
Section 9 - Pollutant Loadings and Pollutant Load Reduction Estimates
Table 9-5 (Continued)
Airport
ID
Airport
Airport
Weighting
Factor
Current
ADF
Collection
(%)
Baseline
COD Load
(pounds)
COD Load
Reduction for
20% Collection
and Control
Scenario
(pounds)
COD Load
Reduction for
40% Collection
and Control
Scenario
(pounds)
1130
San Antonio International
1.0000
0
121,626
23,717
47,434
1131
Wilkes-Barre/Scranton
International
2.6815
0
405,801
79,131
158,262
1133
Phoenix Sky Harbor
International
1.0000
20
0
0
0
1135
Lafayette Regional
6.6425
0
14,201
8,521
8,521
1136
General Mitchell International
1.0000
44
852,970
0
0
1137
Dallas Love Field
1.0000
40
213,039
0
0
1138
Detroit Metropolitan Wayne
County
1.0000
>60
0
0
0
1139
Philadelphia International
1.0000
>60
1,436,522
0
0
1140
Memphis International
1.0000
0
1,946,410
379,550
759,100
1141
Ronald Reagan Washington
National
1.0000
40
1,229,789
0
0
1142
Washington Dulles
International
1.0000
40
5,686,802
0
0
1143
San Francisco International
1.0000
>60
0
0
0
1144
Central Wisconsin
3.0156
0
416,170
81,153
162,306
1145
Newark Liberty Intl
1.0000
0
10,762,687
2,098,724
4,197,448
1146
Northwest Arkansas Regional
1.8782
0
293,595
57,251
114,502
1147
Raleigh-Durham Intl
1.0000
0
977,382
190,589
381,179
1148
Kansas City Intl
1.0000
40
1,200,632
0
0
NA - Ketchikan was sent an airport questionnaire but did not respond.
Sources: Airport Deicing Loadings Database. (USEPA, 2010); ADF Capture and Control Efficiency Review
Memorandum. (ERG, 2011)
* The airport post-questionnaire has installed deicing pads; high BOD stormwater is sent to a POTW.
For each scenario, EPA estimated no load reductions for the airport if it collects and
controls more than the required percentage of available ADF (e.g., for the 20 percent efficiency
scenario, if an airport currently collects and controls 20 percent or more of available ADF, no
load reductions were estimated for the airport). Model airports that currently collect the required
percentage of available ADF either treat it to the required discharge levels, discharge the
collected ADF to a POTW, or send it off-site and are assumed to be in compliance with any
numeric effluent limitation.
EPA assumed that airports that used small quantities of ADF (less than 5,000 gallons of
normalized ADF), as described below in Section 10.1, would collect and haul away the required
percentage of ADF instead of collecting it for on-site treatment. For more information, refer to
thq Airport Deicing Loadings Calculations memorandum (ERG, 2008b).
106
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Technical Development Document for Effluent
Limitation Guidelines and Standards for the Airport Deicing Category
Section 9 - Pollutant Loadings and Pollutant Load Reduction Estimates
9.3 Airfield Deicing Pollutant Loading
This section presents EPA's methodology for estimating airfield deicing pollutant loads
using airport questionnaire data on airfield chemical use.
9.3.1 Estimate the Amount of Applied Deicing Chemical
In the airport questionnaire, EPA requested that airport personnel report the usage
amount, concentration, and brand name of the following pavement deicing materials for the
2002/2003, 2003/2004, and 2004/2005 deicing seasons:
Urea;
Potassium Acetate;
CMA;
Sodium Acetate;
Sand;
Sodium Formate;
EG-Based Fluids;
PG-Based Fluids; and
Other: (Specify).
EPA evaluated the data provided for each reported chemical to determine the most
appropriate way to estimate the average amount used over the three winter seasons reported. In
addition, EPA read the comments provided by the airport personnel to determine any extenuating
circumstances that affect chemical use. For example, airport personnel may have reported that
urea was replaced with potassium acetate at the airport during the three years reported. In this
case, EPA used the potassium acetate average in the loadings estimate and did not use any of the
urea data to better represent the airport's current practices. Ninety airports reported pavement
deicing chemical usage values to EPA in their questionnaire responses.
Table 9-6 shows the three-year average pavement deicing chemical usage EPA calculated
from the reported data (normalized to pure chemical) by airport and chemical. In the
questionnaire, airports reported pounds or gallons of pavement deicing chemical used along with
the concentration of the chemical. If airport personnel reported a volume of chemical in the
airport or airline detailed questionnaire, EPA multiplied the reported volume by the reported
deicing chemical strength and the chemical density.
No airports reported using CMA. Multiple airports reported using sand, but these data are
not included in Table 9-6, because sand was not included in the loads analysis. Only one airport
reported using granular potassium acetate. Potassium acetate (in the liquid form) is the most
commonly used pavement deicing chemical.
107
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Technical Development Document for Effluent
Limitation Guidelines and Standards for the Airport Deicing Category
Section 9 - Pollutant Loadings and Pollutant Load Reduction Estimates
Table 9-6. Three-Year Average Amount of Pavement Deicing Chemical Usage, in Pounds
Airport
ID
Airport Name
EG-Based
Fluids
Granular
Potassium
Acetate
Potassium
Acetate
Sodium
Acetate
Sodium
Formate
PG-Based
Fluids
Urea
1006
Chicago O'Hare Intl
0
0
655,284
0
0
4,681,462
0
1007
Yeager
0
0
0
2,560
0
11,540
27,517
1010
Fairbanks Intl
0
0
197,024
0
0
0
332,000
1011
Lambert - St Louis Intl
0
0
5,119,502
0
0
0
0
1012
Ted Stevens Anchorage Intl
0
0
1,266,417
0
0
0
2,514,900
1013
Wiley Post-Will Rogers Mem
0
0
0
0
0
0
20,000
1014
Albuquerque Intl Sunport
0
0
4,586
0
0
0
0
1016
Tri - State/Milton J Ferguson Field
0
0
27,089
0
0
0
56,000
1017
Austin Straubel Intl
0
0
38,121
0
0
0
44,860
1018
Piedmont Triad Intl
0
0
53,938
0
0
0
92,667
1020
Hartsfield - Jackson Atlanta Intl
0
0
314,456
0
0
0
0
1021
Buffalo Niagara Intl
0
0
0
0
7,760
0
0
1022
Fort Wayne Intl
0
0
268,772
0
0
0
285,544
1023
Seattle - Tacoma Intl
0
0
97,914
696
0
0
0
1024
Indianapolis Intl
0
0
783,038
470,667
0
0
0
1026
Dallas/Fort Worth Intl
0
0
18,179
0
0
0
0
1028
Denver Intl
0
0
3,526,704
0
0
0
0
1029
La Guardia
0
0
1,118,145
1,676
0
442,700
0
1031
Richmond Intl
0
0
284,770
17,000
0
0
0
1032
Austin - Bergstrom Intl
0
0
17,483
0
0
0
0
1036
Baltimore - Washington Intl
0
0
1,178,861
257,280
156,800
0
0
1041
Glacier Park Intl
0
0
0
0
0
0
333
1043
Ralph Wien Memorial
0
0
38,870
0
0
0
10,000
1044
Roanoke Regional/Woodrum Field
0
0
109,044
0
0
0
0
1050
Aspen - Pitkin County/Sardy Field
0
17,000
46,732
0
0
0
0
1052
Wilmington Intl
0
0
0
0
0
0
0
1053
General Edward Lawrence Logan Intl
1,217,300
0
0
0
0
0
10,217
-------
Technical Development Document for Effluent
Limitation Guidelines and Standards for the Airport Deicing Category
Section 9 - Pollutant Loadings and Pollutant Load Reduction Estimates
Table 9-6 (Continued)
Airport
ID
Airport Name
EG-Based
Fluids
Granular
Potassium
Acetate
Potassium
Acetate
Sodium
Acetate
Sodium
Formate
PG-Based
Fluids
Urea
1057
Will Rogers World
0
0
49,603
2,910
0
0
0
1058
Gerald R Ford Intl
0
0
66,341
0
8,568
0
0
1059
Greater Rochester Intl
0
0
294,634
0
0
0
0
1063
Evansville Regional
0
0
29,065
0
0
0
0
1065
Albany Intl
0
0
196,535
148,500
0
0
0
1066
Salt Lake City Intl
0
0
173,169
0
0
0
1,121,232
1068
Eppley Airfield
0
0
289,288
9,474
0
0
0
1069
Cleveland - Hopkins Intl
0
0
2,456,657
190,055
6,117
0
0
1070
City of Colorado Springs Municipal
0
0
224,598
0
0
0
0
1071
Tweed - New Haven
0
0
0
291
0
0
0
1074
South Bend Regional
0
0
0
0
0
0
32,440
1078
Nashville Intl
0
0
163,779
0
0
0
0
1079
Manchester
0
0
398,780
0
0
0
36,833
1080
Syracuse Hancock Intl
0
0
11,792
0
0
0
0
1082
Trenton Mercer
0
0
12,393
0
4,704
0
0
1084
Bismarck Municipal
0
0
16,114
0
0
0
0
1085
Waterloo Municipal
0
0
0
0
0
0
6,000
1088
Outagamie County Regional
0
0
229,290
0
0
0
0
1089
John F Kennedy Intl
0
0
170,330
3,460,831
0
224,792
0
1090
Boise Air Terminal/Gowen Field
0
0
98,582
0
0
0
269,901
1094
Boeing Field/King County Intl
0
0
10,255
0
0
0
0
1095
Chicago Midway Intl
0
0
1,397,274
0
0
0
0
1098
Aberdeen Regional
0
0
17,489
0
0
0
0
1100
Toledo Express
0
0
240,209
0
0
0
0
1101
Portland Intl
0
0
256,478
10,292
211,183
0
0
1103
Juneau Intl
0
0
0
0
0
0
478,000
-------
Technical Development Document for Effluent
Limitation Guidelines and Standards for the Airport Deicing Category
Section 9 - Pollutant Loadings and Pollutant Load Reduction Estimates
Table 9-6 (Continued)
Airport
ID
Airport Name
EG-Based
Fluids
Granular
Potassium
Acetate
Potassium
Acetate
Sodium
Acetate
Sodium
Formate
PG-Based
Fluids
Urea
1104
Nome
0
0
39,307
0
0
0
0
1105
Spokane Intl
0
0
240
0
0
951
498,000
1107
Pittsburgh Intl
0
0
1,198,425
13,333
89,507
0
0
1108
Louisville Intl - Standiford Field
0
0
762,020
0
109,760
0
0
1109
Airborne Airpark
0
0
1,916,877
0
1,809,373
0
0
1110
Aniak
0
0
0
0
0
0
2,400
1111
Port Columbus Intl
0
0
623,773
0
7,161
0
0
1112
Deadhorse
0
0
12,229
0
0
0
20,000
1113
Cincinnati/Northern Kentucky Intl
0
0
3,050,218
0
4,000
0
0
1114
Stewart Intl
0
0
78,614
2,520
0
0
151,800
1116
Reno/Tahoe Intl
0
0
42,583
0
0
0
11,186
1117
Cherry Capital
0
0
63,909
0
0
0
0
1118
Bethel
0
0
0
0
0
0
67,333
1119
Rickenbacker Intl
0
0
71,919
0
37,782
0
0
1120
Rapid City Regional
0
0
0
0
0
6,484
0
1121
Theodore Francis Green State
0
0
160,532
0
0
0
0
1123
James M Cox Dayton Intl
0
0
174,912
0
0
0
0
1124
Des Moines Intl
0
0
340,660
139,033
0
0
0
1126
Minneapolis /St Paul Intl/Wold -
Chamberlain
0
0
1,273,019
82,667
0
0
0
1128
Charlotte/Douglas Intl
0
0
109,356
0
0
0
149,883
1129
Bradley Intl
0
0
443,282
223,150
0
0
16,748
1136
General Mitchell Intl
0
0
1,275,038
0
127,400
0
0
1137
Dallas Love Field
0
0
218
0
0
0
0
1138
Detroit Metropolitan Wayne County
0
0
1,851,138
0
0
0
0
1139
Philadelphia Intl
0
0
0
0
0
809,829
0
-------
Technical Development Document for Effluent
Limitation Guidelines and Standards for the Airport Deicing Category
Section 9 - Pollutant Loadings and Pollutant Load Reduction Estimates
Table 9-6 (Continued)
Airport
ID
Airport Name
EG-Based
Fluids
Granular
Potassium
Acetate
Potassium
Acetate
Sodium
Acetate
Sodium
Formate
PG-Based
Fluids
Urea
1140
Memphis Intl
0
0
496,699
74,325
0
0
0
1141
Ronald Reagan Washington National
0
0
319,347
34,000
0
0
78,000
1142
Washington Dulles Intl
0
0
2,430,542
619,868
0
0
0
1144
Central Wisconsin
1,858
0
59,419
0
0
0
123,440
1145
Newark Liberty Intl
0
0
2,657,040
6,143
0
0
0
1146
Northwest Arkansas Regional
243,723
0
0
0
0
0
18,000
1147
Raleigh - Durham Intl
0
0
0
0
0
0
63,333
1148
Kansas City Intl
0
0
597,465
4,573
0
0
0
1149
Fort Worth Alliance
0
0
5,241
0
0
0
0
1150
Greater Rockford
0
0
311,914
0
0
0
680,267
1151
Kalamazoo/Battle Creek Intl
0
0
0
4,000
0
0
0
1153
Akron - Canton Regional
0
0
20,073
162
0
0
21,333
Source: Airport Deicing Loadings Database (USEPA, 2010).
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Technical Development Document for Effluent
Limitation Guidelines and Standards for the Airport Deicing Category
Section 9 - Pollutant Loadings and Pollutant Load Reduction Estimates
9.3.2 Calculate the Amount of Pollutant Load Associated with the Applied Chemical
As airfield deicing chemicals break down in the environment, they (like aircraft deicers)
result in increased COD and BOD discharges. EPA calculated the amount of COD associated
with the degradation of the applied pavement deicing chemicals. Because pavement deicers
containing urea will also break down into ammonia, EPA also calculated the amount of ammonia
associated with the degradation of these deicers.
As with the aircraft deicers, EPA determined it would not be suitable to use empirical
data to estimate loadings and decided to calculate loadings based on standard chemical
information and stoichiometric equations.
Determine the ThOD of Each Chemical
As with aircraft deicers, the ThOD estimate was based on the molecular formula of the
chemical and the stoichiometric equation of the breakdown of the chemical to the end products
of carbon dioxide and water. Table 9-7 lists the calculated ThOD for each chemical in airfield
deicer.
Table 9-7. ThOD Calculations for Airfield Deicing Chemicals
Deicing Compound
Molecular
Formula
Stoichiometric Formula
ThOD (Moles of 02
per Mole of Deicing
Compound)
EG
C2H6O2
2[C2H602] + 5 02 ^ 4 C02 + 6 H20
2.5
Urea
N2H4CO
N2H4CO + 4 02 2 HNO3 + C02 + H20
4.0
Potassium acetate
KC2H302
[C2H302]"+ 1.75 02 -> 2 C02 + 1.5 H20
1.75
Sodium acetate
NaC2H302
[C2H302]"+ 1.75 02 -> 2 C02 + 1.5 H20
1.75
Calcium magnesium acetate
C8H12CaMg08
[C8H1208]4~+ 7 02 -> 8 C02 + 6 H20
7.0
Sodium formate
NaHC02
2[HC02]"+ 0.5 02 -> 2 C02 + H20
0.25
Determine the COD of Each Chemical
EPA next determined the COD loading associated with the chemical's degradation. EPA
assumed that the chemical would completely degrade in the environment over time and therefore
the calculated ThOD load would be equivalent to the COD load. EPA estimated the COD load
associated with each reported chemical based on the calculated mass of the chemical purchased,
the molecular weight of the chemical, the ThOD, and the molecular weight of oxygen, using the
equation below:
w . s , s 434 grams moles of chemical
COD Load (pounds) = Chemical (pounds) x x Chemical Molecular Weight
pound I grams of chemical
X ThOD {"1ฐ'esฐf0i ) X O, Molecular Weigh/ 8ramsofฐ2] x -E225_
^ moles of chemical) \ moles of O2 J 434 grams
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Limitation Guidelines and Standards for the Airport Deicing Category
Section 9 - Pollutant Loadings and Pollutant Load Reduction Estimates
9.3.3 Estimate the Amount of Baseline Pollutant Load that is Discharged Directly
As pavement deicing chemicals are applied at a large variety of areas at an airport, the
amount of pavement deicers being directly discharged could range from close to 100 percent on
pavement areas near outfall drains, to nearly 0 percent for chemicals that may fall onto grassy
areas and infiltrate into the ground during a thaw. Estimating a percentage of direct discharge
release of pavement deicers at a particular airport is difficult without performing a detailed study
of each airport. Therefore, EPA assumed 100 percent direct discharge of pavement deicers to
represent the maximum possible amount of discharge.
9.3.4 Estimate Pollutant Reductions for Each EPA Collection/Control Scenario
Urea COD Load Reduction
As described in section 9.3.2, EPA calculated the COD load associated with urea use at
the surveyed airports. EPA then evaluated the amount of potassium acetate that would be
required to replace the current average urea use using a comparison of application rates under
varying winter conditions (see EPA's Urea/Potassium Acetate memorandum (ERG, 2010) for the
details of this analysis). Based on the COD load associated with the equivalent potassium acetate
use, EPA determined the potential reductions in COD load. Table 9-8 presents by airport the
COD load associated with urea use, the COD load associated with a switch to potassium acetate
use, and the potential COD load reduction that would result from airfield product substitution.
Urea Ammonia Load Reduction
Because ammonia is not associated with potassium acetate use, the amount of ammonia
reduction from a urea product substitution is equal to the amount of ammonia associated with
urea usage.
The following equation expresses the breakdown of urea to ammonia:
N2H4CO + H20 -> 2 NH3 + 2 H20 + C02
EPA estimated the ammonia load associated with urea based on the equation above, the
mass of urea use, and the molecular weights of urea and ammonia, using the equation below:
, TT , , s 434 grams TT ,, , mole of urea
Ammonia Load (pounds) = Urea (pounds) x x Urea Molecular Weight1
pound ^ grams of urea J (9-2)
'2 moles of ammonia , , , , , grams ammonia pound
1 : Ammo ma Molecular W eight
^ mole of urea J mole of ammonia) 434 grams
Table 9-8 presents by airport the potential ammonia load reduction that would result from
airfield product substitution.
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Limitation Guidelines and Standards for the Airport Deicing Category
Section 9 - Pollutant Loadings and Pollutant Load Reduction Estimates
Table 9-8. Baseline Ammonia and COD Load and Potential Load Reduction Associated
with the Discontinued Use of Urea as an Airfield Deicing Chemical for In-Scope Airports
Airport
ID
Airport
Airport
Weighting
Factor
U rca Load
(lbs of
COD)
Equivalent
Potassium
Acetate Load
(lbs of COD)
Potential
Load
Reduction
(lbs of
COD)
Potential
Load
Reduction
(lbs of
Ammonia)
1007
Yeager
2.1508
58,644
16,172
42,471
15,572
1010
Fairbanks Intl
1.0000
707,559
195,127
512,432
187,883
1012
Ted Stevens Anchorage Intl
1.0000
5,359,760
1,478,087
3,881,674
1,423,212
1017
Austin Straubel Intl
2.3269
95,606
26,366
69,240
25,387
1018
Piedmont Triad Intl
1.0000
197,491
54,463
143,028
52,441
1022
Fort Wayne Intl
1.9682
608,551
167,823
440,728
161,593
1041
Glacier Park Intl
3.1409
710
196
514
189
1043
Ralph Wien Memorial
1.0000
21,312
5,877
15,435
5,659
1053
General Edward Lawrence
Logan Intl
1.0000
21,774
6,005
15,769
5,782
1066
Salt Lake City Intl
1.0000
2,389,572
658,984
1,730,588
634,519
1074
South Bend Regional
2.1417
69,136
19,066
50,070
18,358
1079
Manchester
1.0000
78,499
21,648
56,851
20,844
1090
Boise Air Terminal/Go wen
Field
1.5043
575,214
158,629
416,584
152,740
1103
Juneau Intl
1.0000
1,018,715
280,936
737,779
270,506
1105
Spokane Intl
1.5192
1,061,339
292,690
768,648
281,824
1114
Stewart Intl
2.8661
323,516
89,218
234,299
85,905
1116
Reno/Tahoe Intl
1.0000
23,840
6,574
17,265
6,330
1118
Bethel
1.0000
143,501
39,574
103,927
38,105
1128
Charlotte/Douglas Intl
1.0000
319,432
88,091
231,340
84,821
1129
Bradley Intl
1.0000
35,692
9,843
25,849
9,478
1141
Ronald Reagan Washington
National
1.0000
166,234
45,843
120,391
44,141
1144
Central Wisconsin
3.0156
263,076
72,550
190,526
69,856
1146
Northwest Arkansas
Regional
1.8782
38,362
10,579
27,782
10,186
1147
Raleigh - Durham Intl
1.0000
134,976
37,223
97,753
35,841
Source: Airport Deicing Loadings Database. (USEPA, 2010).
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Limitation Guidelines and Standards for the Airport Deicing Category
Section 9 - Pollutant Loadings and Pollutant Load Reduction Estimates
9.4 References
ERG. 2008a. Memorandum from Steve Strackbein (ERG) to Brian D'Amico and Eric Strassler
(U.S. EPA). The Development of Snow and Freezing Precipitation (SOFP) Days and the Aircraft
Deicing and Anti-icing Fluid (ADAF) Factor. (January 16). DCN AD00856.
ERG. 2008b. Memorandum from Cortney Itle (ERG) to Brian D'Amico (U.S. EPA). Airport
Deicing Loadings Calculations. (April 17). DCN AD001140.
ERG. 2010. Memorandum from Steve Strackbein and Mary Willett (ERG) to Brian D'Amico
and Eric Strassler (U.S. EPA). Estimated Costs for Transition to Liquid Airfield Deicing
Application from Solid Airfield Deicing. (October 8). DCN AD01252.
ERG. 2011. Memorandum from Cortney Itle and Mary Willett (ERG) to Brian D'Amico (U.S.
EPA). A 1)1'' Collection and Control Efficiency Review. (June 15). DCN ADO 1270.
Switzenbaum, et al. 1999. Workshop: Best Practices for Airport Deicing Stormwater. DCN
AD00893.
USEPA. 2008. Airport Deicing Operations ADF Usage Database. U.S. Environmental
Protection Agency. Washington, D.C. DCN AD001141.
USEPA. 2010. Airport Deicing Loadings Database. U.S. Environmental Protection Agency.
Washington, D.C. DCN AD01257.
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Limitation Guidelines and Standards for the Airport Deicing Category
Section 10 - Technology Costs
10. Technology Costs
This section presents EPA's estimates of costs for the Airport Deicing Category to
implement the control and treatment technologies EPA considered as technology bases for
existing airports in the final rule. EPA estimated the compliance costs for each control and
treatment technology to determine potential economic impacts on the industry. EPA also
weighed these costs against the pollutant load reduction benefits resulting from the control and
treatment technologies.
This section discusses the following information:
Section 10.1 - EPA's costing approach using airport-specific data as model
airports;
Section 10.2 - EPA's methodology for estimating aircraft deicing costs associated
with the collection and treatment of ADF-contaminated stormwater, including an
overview of EPA's cost model and example calculations showing how the model
estimates costs;
Section 10.3 - EPA's methodology for estimating airfield deicing costs associated
with urea substitution;
Section 10.4 - Other compliance-related costs; and
Section 10.5 - A summary of EPA's annualized costs evaluated for the final rule.
10.1 Costing Approach
The Agency used a model-site approach to estimate costs for the Airport Deicing
Category. A model airport is an operating airport for which EPA estimated site-specific
compliance costs. In general, these include sites for which EPA has questionnaire responses.
EPA selected an airport-by-airport approach to estimate compliance costs based on a comparison
of information from the model airports, as opposed to a more generalized approach, to better
characterize the current control and treatment systems in place for ADF contaminated
stormwater and to account for current site conditions and airport operations.
For each model airport, EPA developed both capital and operating and maintenance costs
to reduce pollutant discharges from aircraft deicing and from airfield deicing. EPA combined
these costs for each model airport to estimate total costs of each regulatory option evaluated.
EPA then applied a weighting factor to the costs for each airport to estimate national costs for
each option. A description of the weighting factors for the Airport Deicing Category is in DCN
AD01234.
EPA estimated compliance costs for the model airports using information provided in the
airport questionnaire, the detailed airline questionnaire, and from individual airports and vendors.
For any given model airport, the estimated costs may deviate from those that the airport would
actually incur. However, EPA considers the compliance costs to be accurate when aggregated on
an industry-wide basis. These compliance costs are generally broken down into three categories,
costs associated with aircraft deicing, costs associated with airfield deicing, and costs with
documenting compliance with today's regulation.
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Section 10 - Technology Costs
10.2 Aircraft Deicing Costs
This section describes the general methodology for estimating costs for ADF collection
and treatment, including the Airport Deicing Cost Model design and the development of cost
equations that use model-airport-specific inputs. Components of the aircraft deicing costs include
collection, containment and storage, and treatment costs. EPA estimated capital and annual
operating costs for each of these costing components, which were then amortized to generate
model-airport-specific annualized costs.
10.2.1 Overview of the ADF Collection and Treatment Airport Deicing Cost Model
Managing ADF-contaminated stormwater is a multistep process. EPA developed an
Airport Deicing Cost Model to estimate deicing stormwater control costs for each of these steps
and the various alternatives within each step. Costs for each selected alternative are combined for
each airport included in the costing effort to develop cost estimates for the different EPA control
and treatment technology options considered for the final rule. For example, regulatory costs at
an airport may include a combination of alternatives from the collection, containment and
storage, and treatment categories.
The EPA regulatory options were based on requiring an airport to collect and control
deicing stormwater through a variety of mechanisms. Based on information provided in the
airport questionnaire and data gathered during EPA's engineering site visits to various airports,
EPA decided to estimate costs for three collection technologies. Those collection technologies
included GCVs alone, a combination of plug and pump system with GCVs, and use of CDPs.
Each collection alternative is expected to provide a different level of collection efficiency for
ADF-contaminated stormwater. In the final rule, EPA decided to estimate costs for only two of
these technologies, GCVs and plug and pump with GCV, in part due to concerns that space-
constrained airports may not be able to incorporate CDP because of FAA requirements on their
design and siting. EPA estimates that using only GCVs to collect ADF-contaminated stormwater
from areas within the airport where aircraft are deiced will collect 20 percent of the available
ADF. Adding a plug and pump system in combination with GCVs to the existing stormwater
drainage system is expected to collect 40 percent of the available ADF.
Once ADF-contaminated stormwater has been collected, the airport has a variety of
alternatives for control, including disposal at a POTW, off-site recycle and recovery, on-site
recycle and recovery, or on-site treatment and disposal. Each of these alternatives should be
considered by an airport when selecting the appropriate method to manage collected ADF. For
the airport deicing rulemaking option analysis, EPA selected the AFB reactor treatment system
as the basis of costs because of its demonstrated capability to destroy glycols and generate an
effluent suitable for direct discharge. Although AFB treatment systems may be more expensive
to install and operate when compared to other treatment alternatives, EPA's basis of all treatment
conducted via AFB should provide a conservative cost estimate for individual airports to treat
spent ADF. For costing purposes, EPA assumed that all model airports requiring improvement to
meet the collection requirements, except for low ADF usage airports, would install an AFB
system. For airports that occasionally deice aircraft primarily to remove frost, installing
permanent collection and treatment equipment for ADF would not be practical. Instead, EPA
assumes these airports would use contractors to provide deicing stormwater collection and
removal services.
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Section 10 - Technology Costs
EPA assumed that all airports that are required to collect additional ADF will need on-
site containment or storage for the collected deicing stormwater prior to treatment in an AFB
system. The final rule does not require nor is it based on collecting the full volume of wastewater
generated in a deicing season. Rather, storage is included as part of the technology basis for flow
and/or pollutant equalization to support the AFB treatment system. In these cases, containment
and storage selections can include ponds, underground storage tanks, aboveground storage tanks,
or temporary storage tanks (e.g., frac tanks). EPA decided to estimate costs for aboveground
storage tanks in the final rule because they will have less of an impact on subsurface utilities for
which EPA does not have site-specific information. In addition, FAA discourages airports from
installing new stormwater retention ponds, as they can be a lure for birds, which are a safety
hazard for aircraft. Airports may also require additional stormwater piping to transfer collected
ADF-contaminated stormwater from aircraft application areas to storage tanks.
The airport deicing cost model considers each of these alternatives to develop a costing
scheme for collecting and containing ADF-contaminated stormwater at each model airport. The
Airport Deicing Cost Model also takes into account the effectiveness of each model airport's
current control and treatment program for ADF-contaminated stormwater to determine if
additional costing is requiredto comply with the regulatory options considered for the final rule.
In general, EPA's approach to develop costs for the model airports consists of the
following steps:
Step 1: Develop cost equations for each collection, storage, and treatment
alternative evaluated for the final rule;
Step 2: Estimate an airport's current level of ADF-contaminated stormwater
collection based on information provided in the airport questionnaire;
Step 3: Apply the collection and treatment cost equations for the various
components to those airports that currently collect and manage less than the
control and treatment scenario percentage being evaluated to determine airport-
specific capital and annual costs for that scenario and each component; and
Step 4: Estimate total airport-specific annualized costs for each component of the
airport scenario for each control and treatment scenario.
10.2.2 Airport Deicing Cost Model Equation Development
Based on the available data, EPA developed cost equations for the collection, storage,
and treatment technologies that could be applied to those model airports not currently achieving
the required collection percentage. In general, the Agency developed cost equations using cost
data from the BAT model airports representing their entire system rather than attempting to
estimate costs for individual components. EPA believes using system wide costs is a better way
to estimate costs for this regulatory effort because all installed capital and annual operating costs
are rolled under a single value, eliminating the concern that specific components may not have
been included and allowing for more robust estimates. For example, EPA did not prepare costs
for individual components within the AFB treatment system such as reaction vessels, piping,
pumps, flow meters, and buildings, but instead estimated costs for the entire treatment system.
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Section 10 - Technology Costs
EPA used the cost data from the model airports and information supplied by equipment vendors
along with airport-specific information to develop normalized cost equations that could then be
projected to other airports based on common variables. The sections below describe the
development of the normalized cost equations for the collection, transfer and storage, and
treatment system alternatives evaluated by EPA.
10.2.2.1 ADF Collection
Airports use ADF-contaminated stormwater collection alternatives to achieve the targeted
ADF collection percentage. Collection alternatives that EPA selected for costing include
developing a winter operations plan to help manage ADF use and maximize recovery of
available ADF, using glycol collection vehicles to collect ADF from surfaces following aircraft
deicing, and using a plug and pump system to collect ADF. EPA estimates that airports using
GCVs can collect 20 percent of the available ADF, and airports using plug and pump in
combination with GCVs can collect 40 percent of the available ADF. Airports with deicing pads
are expected to collect more than 40 percent of the available ADF and would therefore comply
with the control alternatives evaluated for this final rule.
Winter Operations Plan
A large number of airports currently have a Stormwater Pollution Prevention Plan
(SWPPP) that includes deicing operations during the winter months. However, these SWPPPs
may not provide specific guidance for achieving the regulatory requirements considered for the
final deicing rule. Therefore, EPA envisions that airports will supplement their SWPPP with a
specific winter operations plan that includes information such as methods to verify the
percentage of ADF collection, standard operating procedures for ADF collection technology
systems, and training information for system operators. Once airports have assessed specific
winter operations to collect and control deicing stormwater, they can implement a control and
treatment strategy to decrease the amount of ADF leaving the airport through stormwater
outfalls.
Costs to develop a winter operations plan will likely vary depending on the type of ADF
collection system. EPA assumed that airports targeting 20 percent collection using GCVs would
require 120 hours of engineering labor to prepare the plan and those airports targeting 40 percent
ADF collection using a combination of GCVs with plug and pump would requireapproximately
240 hours of engineering labor. Based on an engineering rate of $100/hour obtained from the
airport questionnaire, the one-time costs to prepare a winter operations plan for 20 percent and
40 percent ADF capture would be $12,000 and $24,000, respectively.
GCVs
Airports use GCVs to collect ADF-contaminated stormwater from various locations
including gate and apron areas, taxi areas, and centralized deicing areas. GCVs can be either
truck-mounted systems or tow-behind units. Drain covers that bond to surfaces to quickly seal
off drains are often used in conjunction with GCVs in the area where aircraft are deiced to allow
the GCVs to collect high-concentration spent deicing fluid.
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To estimate total capital costs for purchasing GCVs and annual operating and
maintenance (O&M) costs for operating GCVs, EPA used information provided by airports in
the airport questionnaire.
All airports that provided costing information, regardless of hub size, maintained three or
less GCVs. EPA used the information presented in Table 10-1 to estimate the number of GCVs
by airport hub size. The Agency assumes that Non-hub, Small Hub, and Medium Hub airports
can operate effectively and efficiently with two GCVs and that Large Hub airports can operate
effectively and efficiently with three GCVs. Additional details regarding costs for GCVs is
provided in a memorandum entitled Estimated Capital and O&M Costs for Glycol Collection
Vehicle Operation (ERG, 2010).
Control of drainage while operating GCVs will vary by airport. For purposes of
estimating GCV costs, EPA assumed that airports use drain covers in combination with the GCV
operation. Variables that could impact drainage control costs include the size of drain covers and
number of drains to be covered. Because these variables are airport-specific and details are not
available, EPA was unable to develop a specific approach to estimate the cost of drain covers
and the labor needed to install them. EPA has instead incorporated a cost increase factor of 20
percent to the annual O&M cost for using GCVs. EPA assumes that a 20 percent increase in
O&M costs for GCVs will cover costs to purchase and replace drain covers and labor to install
and remove the drain covers as needed.
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Section 10 - Technology Costs
Table 10-1. GCV Capital and O&M Costs
Site ID
Hu b Size
Estimated
ADF Usage
(gal/yr)
Number
of GCVs
Total GCV
Capital Costs
Capital Cost
Base Year
2007 GCV
Capital Cost
Total GCV
Annual Cost
Annual
Cost
Base
Year
2007 GCV
Annual
Cost
($/yr)
Unit
Capital
Cost
(S/GCV)
Annual
O&M
Cost
(S/yr)
1136
Medium
152,944
1
$361,355
2001
$415,558
$15,268
2004
$16,184
$415,558
$16,184
1012
Medium
420,735
1
$273,840
2001
$314,916
$80,000
2005
$82,400
$314,916
$82,400
1113
Large
722,995
1
$250,000
1997
$317,500
$5,000
2005
$5,150
$317,500
$5,150
1066
Large
570,540
1
$353,000
2004
$374,180
$374,180
1101
Medium
112,086
2
$700,000
1996
$910,000
$43,236
2004
$45,831
$455,000
$45,831
1021
Medium
284,654
2
$530,000
2001
$609,500
$0
$304,750
1036
Large
323,623
1
$283,463
2006
$283,463
$214,516
2004
$227,387
$283,463
$227,387
1065
Small
125,775
1
$325,000
2005
$334,750
$45,000
2005
$46,350
$334,750
$46,350
1031
Small
59,337
2
$518,300
2001
$596,045
$35,000
2005
$36,050
$298,023
$36,050
AVERAGE
$344,238
$59,773
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Section 10 - Technology Costs
Plug and pump with GCVs
Two airports provided sufficient information to estimate costs for a plug and pump type
collection system. During the 2005 deicing season, the first airport used sewer balloons at eight
locations, storm sewer shutoff valves at four locations, and two catch basin inserts. In addition,
this airport utilized two GCVs for ancillary glycol collection; one is a traditional truck-based
GCV and the other is a GCV unit (a V-Quip Ramp Ranger) that is towed behind a tractor. The
estimated capital cost for this airport's plug and pump system (including the GCVs) is
approximately $790,000. The plug-and-pump system operated at this airport prevents ADF-
contaminated stormwater from discharging through three deicing stormwater outfalls (USEPA,
2006a).
The second airport operates 16 plug and pump locations that prevent ADF-contaminated
stormwater from leaving the airport through a maximum of five outfalls. These plug and pump
operations include plugging the associated drainage pipes and pumping out these drains with
dedicated pumping trucks. According to the airport, the annual budget to operate the plug and
pump system is approximately $1,300,000. This cost includes permit monitoring, glycol
management, the pumping contractor, plus other miscellaneous costs (ERG personnel
communication, May 3, 2007). Because the glycol collection system at this airport is contracted
to a third party, all costs to the airport are reoccurring annual costs. Therefore, these O&M costs
are likely over estimates compared to airports that do not contract out their glycol collection
system operation.
To estimate both capital and annual O&M costs for other airports where plug and pump
collection may be applicable, EPA normalized the costs based on the number of deicing outfalls.
EPA assumed that the number of deicing outfalls is related to the number of areas where aircraft
deicing occurs, so that in general an airport that has a greater number of discontiguous deicing
areas will have a greater number of deicing outfalls. EPA estimated that more deicing areas
would indicate the need for additional costs associated with removing ADF from those areas.
Table 10-2 presents the normalized capital and annual O&M costs for the plug and pump
collection system at the airports for which EPA had costing data.
Table 10-2. Normalized Capital and O&M Costs for the Plug and Pump Collection
System
Airport
Deicing
Outfalls
Total Capital
Cost
(2006 S)1
Annual O&M Cost
(2006 $)
Normalized
Capital Cost
($/outfall)
Normalized Annual
O&M Cost
(S/outfall)
Airport 1
3
$790,000
NA
$263,400
NA
Airport 2
5
NA
$1,300,000
NA
$260,000
NA - Data not available.
Contract Hauling of ADF-Contaminated Stormwater
For airports that occasionally deice aircraft primarily to remove frost, installing
permanent collection and treatment equipment for ADF-contaminated stormwater would not be
practical. Instead, EPA assumes these airports would contract out deicing stormwater collection
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Section 10 - Technology Costs
and removal and their costs would not vary between the 20 percent and 40 percent collection/
control scenarios. This costing approach impacts the following airports:
Ontario International airport in California;
Birmingham International Airport in Alabama;
Montgomery Regional airport in Alabama;
Sacramento Mather airport in California;
Lovell Field airport in Tennessee; and
Lafayette Regional airport in Louisiana.
These airports reported that they do some deicing, but all reported or are estimated to use
5,000 gallons/year or less normalized ADF, had less than 100 percent capture of ADF-
contaminated stormwater, indicated that they discharged ADF-contaminated stormwater to
surface waters, but reported no typical deicing months. Specific details regarding the costs for
occasional removal of ADF-contaminated stormwater by a local contractor is included in a
memorandum entitled Estimated Annual Costs for Airports with Limited ADF Use (ERG, 2008).
10.2.2.2 AFB Treatment System
EPA based the proposed COD discharge limitation on AFB treatment. As such, when
applicable, EPA determined costs for in-scope facilities to treat collected ADF through an AFB
system. EPA also included costs for associated storage and transfer piping.
Transfer Piping
Piping costs to transfer collected stormwater to holding tanks prior to either on-site or
off-site ADF management will vary for each airport. Variables that could impact transfer piping
costs include existing subsurface utilities, soil types, elevation changes, and anticipated peak
precipitation events. Because each of these variables is airport-specific and the details are not
available, EPA estimated costs for each airport to construct 10,000 linear feet of new subsurface
stormwater conveyance piping from various areas around the airport. EPA modified this estimate
from the proposal's 1,000 linear feet after considering public comment.
Elements of a stormwater piping system include subsurface concrete piping, manholes
and catch basins throughout the system to control the direction of flow. EPA obtained costs for
individual elements within the system from RSMeans (RS Means, 2010) and adjusted the costs
to 2006 dollars. The Agency added cost factors for plumbing and site work to the direct costs to
obtain total installed direct costs. Indirect costs for engineering, permits, scheduling,
performance bonds, and contractor markups were added to the total installed direct costs. Table
10-3 shows the estimated installed capital cost for 10,000 linear feet of a new stormwater
conveyance piping system at an airport is approximately $1,140,000. Details regarding capital
costs plus indirect cost factors are provided in a memorandum entitled Estimated Capital and
O&M Costs for Additional Stormwater Piping (ERG, 2010c).
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Table 10-3. Estimated Cost for 10,000 Linear Feet of Stormwater Piping
Description
Total Cost
Trenching for stormwater piping
$59,000
Backfill and compact trench after piping
$38,000
Concrete stormwater piping (18-inch diameter)
$310,200
Manholes/catch basins
$137,400
Manhole frames and covers
28,800
Plumbing (connectors, extra labor, etc.)
$187,500
Site work (clearing, grading, surveying)
$80,300
Engineering
$67,300
Permits
$16,800
Scheduling
$6,700
Performance bonds
$21,000
Insurance (risk, equipment floater, public liability)
$19,300
Contractor markup (handling, procuring, subcontracting, change orders, etc.)
$84,000
Overhead and profit
$84,000
Total Installed Capital Cost for 10,000' of Stormwater Piping
$1,140,000
Source: RS Means Heavy Construction Cost Data, 64th Edition, 2010.
Annual O&M costs for the piping and conveyance system include periodic inspections to
verify integrity of the piping system. To estimate labor costs for TV inspection of the 18" sewer,
EPA made a conservative assumption that an airport would inspect 20 percent of the storm sewer
system annually (2,000 linear feet), at a rate of $1,400 per day (2006 basis). Based on
engineering experience, a sewer TV crew of two to three persons can inspect approximately 500
feet of piping per day. At a rate of $l,400/day, the annual airport inspection cost would be
approximately $5,600.
Storage Tanks for ADF-Contaminated Stormwater
The AFB system that forms the basis for today's COD limitation include storage to
provide both flow and concentration equalization. Storage tanks are used at airports to equalize
either flow and/or concentration of ADF-contaminated stormwater prior to treatment in the AFB
system. The actual size of the storage tank depends primarily on the amount of ADF-impacted
stormwater generated during precipitation events, the area from which deicing stormwater is
collected, and the rate the stormwater can be discharged to the AFB. For costing purposes, EPA
selected aboveground rather than underground storage tanks due to constraints such as existing
underground utilities or high ground water levels at individual airports.
EPA obtained storage tank volumes and capital costs when available from five airports in
the airport questionnaire (USEPA, 2006b). Using normalized ADF usage data for each of these
airports, EPA normalized tank volumes and costs to the annual ADF use per year to provide an
equation that could be used to estimate storage tank sizes and costs at other airports. EPA's
normalized ADF usage amounts represent ADF amounts without any water dilution. EPA chose
ADF usage as the costing basis for tank storage because the amount of tank storage needed is
directly related to the amount of ADF applied for aircraft deicing, which is a function of the
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Section 10 - Technology Costs
frequency, duration, and intensity of precipitation events at a particular airport during a deicing
season. In addition, the storage tanks at each of these airports are used to contain ADF-
contaminated stormwater prior to treatment, and therefore the hydraulic capacity has likely been
designed with equalization requirements (e.g., maximum flow and equalized pollutant
concentrations) in mind.
The data in Table 10-4 indicate the volume of storage tanks at the five airports ranges
between 1.5 million gallons and 8 million gallons, with the average being approximately 4.6
million gallons. The average unit cost for storage tanks calculated from the data in Table 10-4 is
$1.67/gallon. The normalized storage tank volume, calculated from the data provided in Table
10-4, is 11.4 gal/gal ADF use/yr. The basis of the 11.4 gal/gal ADF use/yr factor includes storage
of ADF-contaminated stormwaters from a variety of collection technologies (including GCVs,
diversion systems, and deicing pads) that were identified as having glycol concentrations greater
than 1 percent or in one case greater than 1,000 mg/1 BOD. EPA believes that this factor will
provide sufficient storage volume for those airports required to meet either a 20 or 40 percent
available ADF collection requirement because the airports forming the basis of the factor have an
ADF collection percentage greater than the considered requirement.
Table 10-4. Storage Tank Volumes and Installed Capital Cost for Various Airports
Airport
ADF Use
(gal/yr)
Total Storage
Tank Volume
(gal)
Storage Tank Volume
per ADF Use
(gal/gal/yr)
Installed
Capital Cost
(2006 $)
Storage Tank
Capital Cost
($/gaI)
1
1,043,138
6,520,000
0.4
$795,000 1
$1.89
2
943,982
5,140,000
2.6
NA
NA
3
715,836
8,000,000
11.2
$9,440,000
$1.18
4
112,086
2,000,000
17.8
NA
NA
5
60,246
1,500,000
24.9
$2,890,000
$1.93
AVERAGE
11.4
$1.67
NA - Not available.
1 Cost provided for one 420,000-gallon storage tank.
To determine if the unit cost for aboveground storage tanks was reasonable, EPA
compared the $1.67/gallon unit cost to the cost for permanent storage tanks reported in the
ACRP Fact Sheets (ARCP Fact Sheets). According to Fact Sheet 30, aboveground permanent
storage tank costs range from $1.25 to $1.75/gallon for tanks ranging in size from 500,000
gallons to 1 million gallons. Unit costs for storage tanks between 1 million and 2 million gallons
range from $1.00 to $1.50/gallon. Based on the data in the fact sheets, EPA believes the
$1.67/gallon unit cost factor should provide a conservative estimate of tank costs.
The airport questionnaire responses provided limited data to determine the annual O&M
cost for storage tanks. One airport reported annual O&M costs for its storage tanks ranged
between $50,000 and $100,000. Using ADF usage information for this airport (281,836 gal/yr)
and the reported annual O&M cost for the airport ($75,000/yr), EPA calculated the normalized
annual O&M cost for storage tanks to be $0.27 per gallon of ADF used per year
($75,000/281,836).
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Section 10 - Technology Costs
AFB Treatment Systems
In the proposed rule, EPA used a linear relationship between ADF use and ADF percent
collection to predict AFB costs. Public comments raised the issue that such a relationship does
not consider minimum capital costs for small systems or the economy of scale for larger systems.
All AFB treatment systems, regardless of size, will require basic components such as chemical
dosing systems, gas handling systems, sludge handling systems, storage tanks, in-line monitoring
equipment, and process control systems. For many of these components, cost is independent of
treatment system size.
To assist EPA with developing costs for AFB treatment, industry developed a cost curve
that shows a general relationship between cost and COD load for systems designed to treat
between 500 and 7,000 lbs/day of COD. As shown in Figure 10-1, the cost per pound of COD
removal decreases rapidly for larger load removal systems because of the economy of scale with
the reactor and separator system, and the cost for support buildings and facilities is relatively
constant and not tied to COD loading.
| 7000 -
| 6000 -
^ 5000 -
ง, 4000 -
| 3000 -
^ 2000 -
ฆf 1000 -
U 0 -
0 1000 2000 3000 4000 5000 6000 7000 8000
COD Loading (lbs/day)
-0.6279
y = 275101x
Figure 10-1. AFB Reactor Capital Cost for Treating ADF-Contaminated Stormwater
Using the equation in Figure 10-1 developed from industry comments (See Airport
Council International - North America comments on EPA's Proposed Rule for Effluent
Guidelines for the Airport Deicing Category), EPA can estimate the installed capital cost for an
AFB reactor (excluding storage, transfer piping, and possible land costs) if the COD loading is
known. To test the accuracy of this equation, EPA compared calculated costs to those provided
by Albany International Airport (Albany) for their AFB treatment units. According to Albany
airport staff, the installed cost for their AFB treatment system is approximately $8.1 million
dollars (2006 $). This cost does not include equalization tanks or ponds prior to the AFB,
additional stormwater piping to transfer ADF-contaminated stormwater from areas of generation
to storage, or purchase of additional land to accommodate the AFB treatment reactors or storage.
Based on Albany's design COD loading of 5,200 lbs/day, the equation in Figure 10-1 would
predict an AFB installed cost of $6.6 million dollars (2006 $). Because the estimated cost for the
Albany AFBs, using industry's equation, is within + 20 percent of the actual cost provided by
Albany, EPA concludes the equation shown in Figure 10-1 can be used to predict AFB costs for
all airports.
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Section 10 - Technology Costs
Both the Albany and Akron-Canton (Akron) airports provided annual O&M costs for
their treatment reactors. According to Albany, its annual O&M cost is approximately
$510,000/year. Akron has recently constructed its AFB and did not have actual operating data at
the time of EPA's costing analysis but did provide estimated annual O&M costs of
$195,000/year (McQueen, R. and Arendt, T.). Because annual operating costs for an AFB system
are directly related to the annual amount of ADF use and the collection percentage, EPA
normalized annual AFB reactor annual operating costs to these two factors. Table 10-5 shows the
AFB reactor annual O&M costs normalized to annual ADF usage for Albany and Akron.
Table 10-5. Normalized Annual O&M Costs for the AFB Reactors
Annual ADF
Use (gal/yr)
Estimated Percent
Capture 1
Annual ADF
Captured
Annual O&M
Cost
(2006 $/yr) 1
Normalized Annual
O&M Cost (S/gal
ADF recovered)
Albany
125,775
92
115,713
$510,000
$4.40
Akron
60,264
60
36,200
$195,000
$5.39
AVERAGE
$4.90
Airport deicing loadings database.
Land Costs
EPA has included the opportunity cost of land use for both storage and treatment of
ADF-contaminated stormwater. EPA's approach to estimating this cost is to first estimate the
amount of land needed for storage tanks and the AFB treatment system and then apply an
opportunity cost per square foot. The opportunity cost assumes the land could potentially be
leased for some other use by an airport tenant if not being used for the treatment and storage
system.
To estimate the area of land associated with the AFB treatment system, EPA obtained
information on the footprint of the AFB systems at Albany using Google Earth (Google Earth,
2007). Based on a review of the Google Earth images, EPA estimates the footprint for the AFB
treatment system is approximately 2.4 acres or 104,544 sq.ft. This area would include the
reactors, associated buildings, pump houses, roadways and parking areas, etc.
To predict the amount of land needed for storage tanks, EPA used the following equation
developed for predicting storage tank costs:
Volume of Required Storage Capacity (gal) = ADF Use gal/yr x 13.1 gal/gal/yr
Combining this equation with the one developed from the figure below allows EPA to
estimate the minimum footprint for storage tanks at individual airports based on ADF use. The
equation shown in the figure below is based on storage tanks with a 14-foot sidewall depth.
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Section 10 - Technology Costs
Tank Area Versus Storage Volume
Area (ft2)
90000
80000
70000
60000
50000
40000
y = 0.0095x - 7E-12
30000
20000
10000
0
2,000,000 4,000,000 6,000,000 8,000,000 10,000,000
Storage Capacity (gal)
Because storage tanks require a barrier-free area of approximately 20 feet around the
entire tank for maintenance as well as access roads to the tanks, EPA decided to increase the
minimum tank footprint by 20 percent.
EPA believes that siting of AFB and deicing stormwater storage systems will require that
they be placed away from the terminal and main runway area. To estimate the value of this land
if leased by an airport, EPA obtained leasing information from a number of airports. Based on
the leasing cost data obtained from these airports, EPA selected an estimated $1.00/sq.ft. cost for
purposes of the costing model. Additional information on land costs is included in a
memorandum entitled Estimated Land Requirements and Opportunity Costs for the Anaerobic
Fluid Bed Treatment System and ADF Stormwater Storage Tanks (ERG, 2010d).
10.2.3 Development of Airport Deicing Cost Model Inputs
The key inputs to EPA's Airport Deicing Cost Model include airport operations data and
site-specific precipitation and physical feature data for the model airports.
10.2.3.1 Airport Operations Data
The primary source of airport operations data used in the calculation of collection and
treatment costs were responses to the Agency's 2006 airport questionnaire (U.S. EPA, 2006b).
EPA entered data from all questionnaire responses into an electronic database that it used to
determine if any ADF-contaminated stormwater collection and treatment technologies were
currently utilized and to access reported operations data needed to estimate costs for additional
collection and treatment. EPA used the following specific data from the questionnaire responses:
geographical location, aircraft deicing chemical usage, manner/frequency of deicing discharges,
deicing, and ADF collection operations.
EPA required the following additional airport operating data not requested in the airport
questionnaire to estimate costs: annual ADF use and the number of annual nonpropeller aircraft
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Section 10 - Technology Costs
departures. EPA collected data on annual ADF usage in its airline detailed questionnaire (U.S.
EPA 2006). EPA evaluated annual nonpropeller aircraft departures using data from the Bureau of
Transportation Statistics (BTS).
10.2.3.2 Precipitation Data and Site Characteristics
Estimating costs to collect and treat ADF-contaminated stormwater partially depends
upon the volume of the stormwater. To predict the annual volume of ADF-impacted stormwater
generated at an airport, EPA used precipitation data along with airport site characteristics and
assumed ADF-impacted stormwater would be collected from areas where ADF is applied and
possibly from areas where ADF may drip from the aircraft during taxi and takeoff. EPA obtained
precipitation data from 1976 to 2006 (30 years) from NOAA for each airport questionnaire
respondent and then averaged the data by airport to estimate an airport-specific monthly average.
EPA uses these data, combined with the number of deicing months taken from the questionnaire
responses, to estimate the average annual amount of precipitation that may be contaminated by
ADF.
10.2.4 Airport Deicing Cost Model Design
This section describes how the Airport Deicing Cost Model uses the capital and annual
cost equations, in combination with the model input data, to predict costs for each model airport.
10.2.4.1 Airport Deicing Cost Model Description
EPA developed the Airport Deicing Cost Model using Microsoftฎ Access. The model
uses various tables structured from the airport questionnaire responses to provide input to the
design equations. EPA designed the model to use a series of "Yes - No" statements and its
assessment of the current collection efficiency achieved by an airport to build costs, as
appropriate, based on the appropriate types of collection alternatives needed to achieve the target
collection efficiency.
The Airport Deicing Cost Model provides output costs in Microsoftฎ Excel for each
selected collection alternative, and the treatment system (piping, storage tanks, and AFB
treatment system). The outputs include both installed capital cost and annual O&M costs. Airport
Deicing Cost Model outputs for each airport that is currently not achieving the analyzed percent
control and treatment of ADF-contaminated stormwater are then used to calculate annualized
costs by airport. Section 10.2.5 provides more detail regarding cost annualization. The Airport
Deicing Cost Model collection and control cost output is $0 for those airports which EPA
estimates are achieving the analyzed option for collection and control of available ADF. EPA's
assessment of each airport's current collection and control percentage is provided in the
memorandum entitled ADF Capture and Control Efficiency Review (ERG, 2011).
10.2.4.2 Summary of Airport Deicing Cost Model Equations
The Airport Deicing Cost Model uses capital and annual cost equations in combination
with various input parameters to estimate costs for each option's collection and treatment
technology at each airport. Table 10-6 summarizes the cost equations used by the model, the
input variables, and any assumptions used by the model to estimate costs. The equations in Table
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Section 10 - Technology Costs
10-6 are based on an airport collecting ADF-contaminated stormwater with glycol concentrations
greater than 0.5 percent.
10.2.4.1 Example Cost Calculation
The following example shows how the Airport Deicing Cost Model uses the equations in
Section 10.2.2 along with an airport's questionnaire response to estimate costs. The example
below is designed to more clearly illustrate the Airport Deicing Cost Model.
Example Airport Capital and Annual Costs
Airport A has six deicing outfalls and currently has no collection or control equipment in
place for ADF-contaminated stormwater. The estimate of airport normalized ADF usage is
approximately 490,000 gallons per year of Type 1 and Type IV ADF. The airport has 23 deicing
days per year spanning a five-month period (150 days). The airport does not discharge to a
POTW or contract haul ADF to an off-site recovery/recycle facility. Based on the final rule, the
airport will collect 40 percent of the available ADF using a plug and pump system with GCVs.
Collected ADF contaminated stormwater will be treated by an AFB treatment system.
Winter Operations Plan Development
Engineering Labor: 240 hours x $100/hr = $24,000
Plug and pump Collection System
Plug and Pump Capital Cost: = 6 x $263,400 = $1,580,400
Plug and Pump Annual O&M Cost ($/yr) = 6 x $260,000 = $l,560,000/yr
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Section 10 - Technology Costs
Table 10-6. Airport Deicing Cost Model Equations, Input Variables, and Assumptions
Calculation Description
Equation
Input Variables
Assumptions
Estimates costs for airports to
prepare a one-time winter
operations plan as a supplement to
the current SWPPP.
Winter Operations Plan ($)
20% ADF collection: 120 hours x
$100/hr
40% ADF collection: 240 hours x
$100/hr
Target ADF collection percentage
Labor costs assume airport will contract
with an outside consultant to prepare the
winter operations plan.
Estimates costs to purchase and
operate GCVs to collect 20% of
available ADF. Includes a 20%
factor on the O&M costs for
drainage control.
GCV Capital Cost ($) = $344,238 x
number of GCVs
GCV Annual Cost($/yr) = $59,773 x
number of GCVs x 1.2
Airport hub status
Small, medium and Non-hub airports
require 2 GCVs. Large Hub airports
require 3 GCVs
Estimates costs to install and
operate a block-and pump
collection system with GCVs to
collect 40% of available ADF.
Plug and Pump Capital Cost ($) =
$263,400 x outfall number
Plug and Pump Annual Cost ($/yr) =
$260,000 x outfall number
Number of stormwater deicing outfalls
from the airport questionnaire
The number of deicing outfalls relates to
the number and size of deicing areas
requiring controls.
Estimates costs to install and
operate an AFB bioreactor
treatment system.
AFB COD Load (lbs/day) = ADF Use
x 14.28 x Collect % /100 x
1/operating days
AFB Unit Capital Cost ($/lb/day):
275,101 x (COD Load) 06279
AFB Capital Cost ($): AFB Unit
Capital Cost x COD Load
AFB Annual Cost ($/yr) = ADF Use x
Collect % /100 x $4.90
ADF use from airline detailed
questionnaire
Treatment system operating period
based on deicing months from airline
detailed questionnaire
Collection % from selected collection
technology
Ultimate COD is 14.28 lbs COD/gal
Type I ADF.
Estimated costs to install storage
tanks to equalize collected ADF -
contaminated stormwater.
Storage Tank Capital Cost ($) = ADF
Use x 11.4 x $1.67
Storage Tank Annual Cost ($/yr) =
ADF Use x $0.27
ADF use from airline detailed
questionnaire
Storage tank volume requirement is 11.4
gal per gal of ADF used per year.
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Technical Development Document for Effluent
Limitation Guidelines and Standards for the Airport Deicing Category
Section 10 - Technology Costs
Table 10-6 (Continued)
Calculation Description
Equation
Input Variables
Assumptions
Estimated costs to install an
additional 10,000 linear feet of
stormwater piping to convey ADF-
contaminated water from
collection to treatment.
Piping Capital Cost ($) = $1,140,000
Piping Annual Cost ($/yr) = $5,600
None
Based on 10,000 linear feet of 18"
diameter subsurface piping.
Estimated cost for land to install
storage tanks and an AFB
treatment system.
AFB Treatment System Annual Land
Cost ($/yr) = $104,544
Storage Tank Annual Land Cost ($/yr)
= 1.2 x (ADF Use gal/yr x 13.1
gal/gal/yr x 0.0095 ft2/gal) * $l/ft2
None
ADF use from airline detailed
questionnaire
AFB treatment system can be installed
on 2.4 acres and the lease cost for land is
$l/ft2
Lease cost for land is $l/ft2
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Technical Development Document for Effluent
Limitation Guidelines and Standards for the Airport Deicing Category
Section 10 - Technology Costs
AFB Biological Treatment System
AFB COD Loading = 490,000 gal/yr x 14.38 lbs COD/gal ADF x 0.4 x 1/150 days/yr = 18,789
lbs/day
AFB Unit Capital Cost ($/lb/day): 275,101 x (18,789)"ฐ6279 = $570/lb COD/day
AFB Capital Cost ($): 18,789 lbs/day COD x $570/lb COD/day = $10,711,000
AFB Annual O&M Cost ($/yr): 490,000 x 0.4 x $4.90 = $960,000/yr
Piping System
Piping system capital cost: $1,140,000
Piping system annual O&M cost: $5,600/yr
Storage Tank(s)
Storage Tank Capital Cost ($) = 490,000 x 11.4 x $1.67 = $9,329,000
Storage Tank Annual O&M Cost ($/yr) = 490,000 x $0.27 = $132,300
Land
AFB Cost ($/yr) = $104,544
Storage Tanks ($/yr) = $1.2 x 490,000 gal/yr x 13.1 gal/gal/yr x 0.0095 ft2/gal x $l/ft2= $60,980
The total capital and O&M costs are therefore:
Cosl Calejion
Capilal ( osls (S)
()ซSiM ( osls (SAear)
Winter Operations Plan
24,000
Plug and Pump Collection System
1,580,400
1,560,000
AFB Treatment System
10,711,000
960,000
Piping
1,140,000
5,600
Storage
9,329,000
132,300
Land Opportunity Costs - For AFB Treatment System
-
104,544
Land Opportunity Costs - For Storage
-
60,980
Total
22,784,400
2,823,424
The capital costs are then amortized and added to the annual O&M costs to assess an overall
annualized cost for the facility.
10.2.5 Annualized Costs for ADF Collection and Treatment Alternatives
Table 10-7 presents the annualized costs by airport developed for the two control and
treatment scenarios evaluated by EPA for the final rule. See the Economic Development
document (USEPA, 2012; DCN AD01280) for a more detailed analysis of annualized costs.
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Section 10 - Technology Costs
Table 10-7. Annualized Costs by Model Facility for Control and Treatment1
Airport
ID
Airport
Current ADF
Collection
Annualized Cost for
20% Control and
Treatment Scenario
(2006 $)
Annualized Cost for
40% Control and
Treatment Scenario
(2006 S)
10012
Montgomery Regional (Dannelly
Field)
0
$1,168
$1,168
10033
Ketchikan International
NA
$0
$0
1004
Norfolk International
20
$0
$2,235,548
1006
Chicago O'Hare International
40
$0
$0
1007
Yeager
40
$0
$0
1008
Tucson International
20
$0
$1,069,305
1010
Fairbanks International
>60
$0
$0
1011
Lambert-St Louis International
>60
$0
$0
1012
Ted Stevens Anchorage
International
40
$0
$0
1014
Albuquerque International Sunport
20
$0
$6,269,926
1015
Gulfport-Biloxi International
>60
$0
$0
1017
Austin Straubel International
40
$0
$0
1018
Piedmont Triad International
0
$1,090,753
$8,121,534
10192
Ontario International
0
$1,110
$1,110
1020
Hartsfield - Jackson Atlanta
International
>60
$0
$0
1021
Buffalo Niagara International
40
$0
$0
1022
Fort Wayne International
0
$991,516
$3,272,310
1023*
Seattle-Tacoma International
0
$1,560,687
$3,863,913
1024
Indianapolis International
40
$0
$0
1026
Dallas/Fort Worth International
>60
$0
$0
1028
Denver International
>60
$0
$0
1029
La Guardia
0
$2,976,443
$6,286,465
1031
Richmond International
40
$0
$0
1032
Austin-Bergstrom International
40
$0
$0
1033
Mc Carran International
40
$4,216
$4,216
1034
Metropolitan Oakland
International
>60
$0
$0
1035
San Diego International
>60
$0
$0
1036
Baltimore-W ashington
International
>60
$0
$0
1037
George Bush Intercontinental
Airport/Houston
40
$4,099
$4,099
1040
Louis Armstrong New Orleans
International
>60
$0
$0
1041
Glacier Park International
0
$1,037,252
$1,266,155
1043
Ralph Wien Memorial
0
$605,365
$707,178
1044
Roanoke Regional/Woodrum Field
0
$943,332
$4,095,087
10452
Norman Y. Mineta San Jose
International
10
$0
$0
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Section 10 - Technology Costs
Table 10-7 (Continued)
Airport
ID
Airport
Current ADF
Collection
Annualized Cost for
20% Control and
Treatment Scenario
(2006 $)
Annualized Cost for
40% Control and
Treatment Scenario
(2006 S)
1046
Long Island Mac Arthur
>60
$0
$0
1050
Aspen-Pitkin Co/Sardy Field
40
$0
$0
1052
Wilmington International
0
$654,946
$3,131,737
1053
General Edward Lawrence Logan
International
0
$4,860,377
$6,659,582
1054
Jackson Hole
>60
$0
$0
1057
Will Rogers World
0
$986,385
$2,675,571
1058
Gerald R. Ford International
40
$0
$0
1059
Greater Rochester International
50
$0
$0
1061
William P Hobby
>60
$0
$0
10622
Birmingham International
0
$2,675
$2,675
1063
Evansville Regional
0
$846,931
$1,609,927
1065
Albany International
>60
$0
$0
1066
Salt Lake City International
>60
$0
$0
1067
Helena Regional
>60
$0
$0
1068
Eppley Airfield
0
$1,250,502
$2,132,279
1069
Cleveland-Hopkins International
40
$0
$0
1070
City of Colorado Springs
Municipal
40
$0
$0
1074
South Bend Regional
>60
$0
$0
1075
Pensacola Regional
>60
$0
$0
1078
Nashville International
>60
$0
$0
1079
Manchester
0
$1,600,420
$1,995,084
1080
Syracuse Hancock International
>60
$0
$0
1081
Bob Hope
>60
$0
$0
1083
Tampa International
>60
$0
$0
1084
Bismarck Municipal
0
$770,509
$1,215,970
1086
Palm Beach International
>60
$0
$0
1087
El Paso International
>60
$0
$0
1088
Outagamie County Regional
0
$1,011,102
$2,412,516
1089
John F Kennedy International
0
$3,215,317
$10,136,241
1090
Boise Air Terminal/Gowen Fid
>60
$0
$0
1091
Rochester International
40
$0
$0
1094
Boeing Field/King County
International
40
$0
$0
1095
Chicago Midway International
>60
$0
$0
10972
Lovell Field
0
$3,745
$3,745
10992
Sacramento International
20
$0
$0
1100
Toledo Express
20
$0
$1,767,861
1101
Portland International
20
$0
$2,792,934
135
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Section 10 - Technology Costs
Table 10-7 (Continued)
Airport
ID
Airport
Current ADF
Collection
Annualized Cost for
20% Control and
Treatment Scenario
(2006 $)
Annualized Cost for
40% Control and
Treatment Scenario
(2006 S)
1102
John Wayne Airport-Orange
County
>60
$0
$0
1103
Juneau International
0
$957,795
$2,343,519
1104
Nome
0
$618,441
$1,904,296
1105
Spokane International
>60
$0
$0
1107
Pittsburgh International
>60
$0
$0
1108
Louisville International-Standiford
Field
>60
$0
$0
1111
Port Columbus International
0
$2,029,946
$4,321,331
1113
Cincinnati/Northern Kentucky
International
>60
$0
$0
1114
Stewart International
40
$0
$0
1115
Jacksonville International
>60
$0
$0
1116
Reno/Tahoe International
20
$0
$1,614,875
1117
Cherry Capital
>60
$0
$0
1118
Bethel
0
$643,331
$1,936,511
1119
Rickenbacker International
0
$710,969
$1,433,955
1120
Rapid City Regional
0
$838,073
$4,548,952
1121
Theodore Francis Green State
>60
$0
$0
1122
Southwest Florida International
>60
$0
$0
1123
James M Cox Dayton International
>60
$0
$0
1124
Des Moines International
40
$0
$0
1126
Minneapolis/St Paul
InternationalAV old-Chamberlain
>60
$0
$0
1128
Charlotte/Douglas International
0
$1,574,890
$2,111,996
1129
Bradley International
>60
$0
$0
1130
San Antonio International
0
$780,240
$5,064,195
1131
Wilkes-Barre/Scranton
International
0
$971,556
$1,476,180
11332
Phoenix Sky Harbor International
20
$0
$0
11352
Lafayette Regional
0
$1,536
$1,536
1136
General Mitchell International
44
$0
$0
1137
Dallas Love Field
40
$0
$0
1138
Detroit Metropolitan Wayne
County
>60
$0
$0
1139
Philadelphia International
>60
$0
$0
1140
Memphis International
0
$1,740,377
$3,651,474
1141
Ronald Reagan Washington
National
40
$0
$0
1142
Washington Dulles International
40
$0
$0
1143
San Francisco International
>60
$0
$0
136
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Section 10 - Technology Costs
Table 10-7 (Continued)
Airport
ID
Airport
Current ADF
Collection
Annualized Cost for
20% Control and
Treatment Scenario
(2006 $)
Annualized Cost for
40% Control and
Treatment Scenario
(2006 S)
1144
Central Wisconsin
0
$952,550
$1,451,583
1145
Newark Liberty Intl
0
$5,366,144
$9,674,611
1146
Northwest Arkansas Regional
0
$873,730
$1,644,615
1147
Raleigh-Durham Intl
0
$1,294,323
$4,254,332
1148
Kansas City Intl
40
$0
$0
1 Treatment includes installation and operation of an AFB biological treatment system.
2 Airport is in a warm climate and uses either no ADF or less than 5,000 gal/yr.; EPA assumes the airport will
contract out all ADF removal and disposal operations.
3 Airport was sent an airport questionnaire but did not respond.
*The airport post-questionnaire has installed deicing pads. High BOD stormwater is sent to a POTW.
10.3 Airfield Deicing Costs
This section describes EPA's cost evaluation for model airports to discontinue using urea
as an airfield deicing chemical. Information collected by EPA during the rulemaking effort
indicated that use of urea as an airfield deicing chemical is being phased out due to concerns
with its environmental impacts and the availability of less harmful alternatives. Responses to
EPA's airport questionnaire indicated that potassium acetate was by far the predominant airfield
deicing chemical in use from 2002 to 2005, representing about 80 percent of all airfield deicing
chemical use; therefore, EPA assumed that airports would switch to this chemical to deice their
pavement. However, approximately 35 of the surveyed airports continued to use urea for airfield
deicing during the 2002/2003, 2003/2004, and 2004/2005 deicing seasons. EPA did not estimate
capital or operating costs associated with airfield deicing control for model airports that did not
report urea usage.
10.3.1 Urea and Potassium Acetate Chemical Costs and Application Rates
EPA evaluated the chemical cost of using urea compared to the chemical cost to use
potassium acetate in evaluating costs for controlling discharges associated with pavement
deicing. This section presents information on the chemical, mechanical, and storage costs to
replace urea with potassium acetate. Additional details on urea and potassium acetate use is
included in a memorandum entitled Estimated Costs for Transition to Liquid Airfield Deicing
Application from Solid Airfield Deicing (ERG, 2010a).
Based on responses to the airport questionnaire (USEPA. 2006b), 19 of the airports that
used urea also used potassium acetate. EPA attempted to contact these airports to obtain their
unit costs for both chemicals and were able to get unit cost data from eight of these airports.
Table 10-8 presents the average cost for urea and potassium acetate during the 2002-2005 time
frame for these eight airports.
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Table 10-8. Average Cost for Urea and Potassium Acetate, 2002-2005
Year
Average U rca Cost
Average Liquid Potassium Acetate Cost
2002
$268.17/ton
$2.81/gallon
2003
$280.57/ton
$2.86/gallon
2004
$297.90/ton
$2.86/gallon
2005
$300.21/ton
$2.92/gallon
Potassium acetate is applied at different rates depending on the weather conditions and
the thickness of the ice layer at the time of application. Table 10-9 shows the typical deicing,
anti-icing, and prewetting application rates for four commercial potassium acetate runway
deicers.
Table 10-9. Typical Application Rates for Potassium Acetate
Brand Name
Deicing Application Rates
Anti-Icing
Application Rates
Prewetting Application Rates
Safewayฎ KA Runway
Deicing Fluid
1 gal/1000 ft2
0.4gal/1000ft2
70% solid and 30% liquid
Cryotech E-36ฎ LRD
1 gal/1000 ft2 (thin ice) and
3 gal/1000 ft2 (2.5cm thick
ice)
0.5 gal/1000ft2
85-95% solid and 5-15% liquid,
or 130g/kg of solid deicer,
1.25gal/1001bs. solid deicer
IceClear RDF
1 gal/1000 ft2 (thin ice) and
3 gal/1000 ft2 (lin. thick ice)
0.5 gal/1000ft2
PEAKฎ PA
1 gal/1000 ft2
0.4 gal/1000ft2
70% solid and 30% liquid
Although it could not obtain actual application rates for urea at individual airports, EPA
did obtain airfield application rates for sodium acetate; therefore, the Agency used sodium
acetate rates as a surrogate to estimate urea application rates. The amount of sodium acetate
required to provide the same protection as urea is between 66 and 70 percent (Transport Canada,
1998). EPA used this relationship to calculate the corresponding urea application rates. Table
10-10 lists typical application rates for Cryotech NAACฎ, a commercial sodium acetate deicer
and the corresponding urea application rate based on the relationship between sodium acetate
and urea.
Table 10-10. Application Rates for Sodium Acetate and Urea
Sodium Acetate, Cryotech NAACฎ, Application
Rate
Urea Application Rate
Near 32ฐF on thin ice = 3-5 lbs/1000 ft2
Near32ฐF on thin ice = 4.3-7.1 lbs/1000 ft2
Less than 10ฐF on 1 inch ice = 10-25 lbs/1000 ft2
Less than 10ฐFb on 1 inch ice = 14.3-35.7 lbs/1000 ft2
Using the information in Table 10-10, EPA estimated the application costs for urea and
potassium acetate based on the 2005 average unit costs ($/l,000 ft2), as shown in Table 10-11.
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Section 10 - Technology Costs
Table 10-11. Cost for Application of Urea and Potassium Acetate, per 1000 Square Feet
Chemical
Deicing Application Cost
(per 1000 ft2)
Anti-Icing
Application Cost
(per 1000 ft2)
Urea
$0.65-$ 1.07, Near 32ฐF on thin ice
Potassium Acetate
$2.92 (thin ice) and $8.76 (thick ice)
$1.17-$1.46
10.3.2 Mechanical Application Equipment and Storage of Potassium Acetate
Airports that change from urea to potassium acetate for airfield deicing will need new
application equipment to apply a liquid rather than a solid as well as liquid storage tanks to
contain potassium acetate during the deicing season. The following sections discuss the costs for
mechanical application equipment and storage tanks for liquid potassium acetate.
10.3.2.1 Mechanical Application Equipment
Airports require application equipment to spread chemical deicers on the airside
pavement. A change from solid to liquid chemicals will require an airport to purchase or retrofit
equipment to properly apply liquid chemical deicers. EPA requested liquid chemical application
equipment costs from vendors across the country that offer a variety of different application
equipment options and obtained costs from three vendors. EPA requested information on
equipment of various sizes to assess costs by a large vs. small/medium coverage area.
Based on information provided by the vendors, EPA assumed that new trucks with a
large coverage area operated with 100-foot spraying booms and at least 2,500 gallons of tank
space. For truck retrofits or trailers, EPA assumed a large coverage area for units that operated
with at least 75-foot booms and at least 2,000 gallons of tank space. EPA assumed that new
trucks with a small/medium coverage area operated with 50-foot spraying booms and at least
1,100 gallons of tank space. For truck retrofits or trailers, EPA assumed a small/medium
coverage area for units that operated with booms of 50 feet or a different type of spreading
mechanism. EPA used this information to estimate liquid application equipment costs for those
airports that currently use solid urea.
Table 10-12 provides costing information for small/medium and large liquid deicer
application equipment. Equipment is presented for two types of installations: new sprayer trucks
and truck retrofits/towed sprayers. Costs are presented as a total capital cost and are averaged by
equipment type and size.
EPA assumed that small, medium, and Non-hub airports would be required to purchase a
medium-size spreader truck and a medium-size truck retrofitted with a tow unit for application of
potassium acetate. EPA assumed Large Hub airports would purchase a large-size spreader truck
and a large-size truck retrofitted with a towed unit. Based on these equipment assumptions and
the relationship between urea and potassium acetate amounts, EPA estimated small, medium and
Non-hub airports would be required to spend approximately $203,000 for a potassium acetate
application system and large airports would be required to spend approximately $348,000. EPA
assumed that airports using both urea and potassium acetate have sufficient application
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Section 10 - Technology Costs
equipment available to apply only potassium acetate and those airports were not assigned
application equipment costs.
10.3.2.1 Potassium Acetate Storage Tanks
Users of liquid pavement deicers can purchase the chemicals in various size carboys or in
bulk. The actual size of bulk liquid storage tanks needed will depend primarily on the amount of
deicing chemical purchased each deicing season. EPA used tank cost data from fact sheets
contained in ARCP Report 14 (ARCP Fact Sheets) to estimate liquid pavement deicer storage
costs for airports that currently use solid urea for airfield deicing and would need to convert to a
non-urea-containing deicing chemical.
Table 10-12. Application Equipment Costs for Liquid Pavement Deicer
Installation
Type
Large
Coverage
Deicing Unit
Medium/Small
Coverage
Deicing Unit
Full Truck
$160,000
Tyler Ice AD Series - 4,000
Gallons with 100' Booms
(Eagle)
$130,000
Tyler Ice AD Series - 2,000
Gallons with 75' Booms (Eagle)
$280,000
4,000-5,000-gallon units
(Tyler ICE)
$197,500
2,000-3,000-gallon unit (Tyler
ICE)
$245,000
ASP nozzle sprayer spraying
width 45 Meter. Tank content
10,000 liter (Schmidt)
Average Cost1
$228,000
$163,000
Installation
Type
Large
Coverage
Deicing Unit
Medium/Small
Coverage
Deicing Unit
Truck Retrofit/
Spreader
$110,000
3,500 2T 5M Towed
Spreader (Eagle)
$35,000
Smart Tote 125, 8-25' spray
width (Eagle)
$35,000
Epoke PC Compact, Drop
behind spreader (Eagle)
$130,000
Tyler Ice TAD Series, 2,000
gallons with 75' booms
(Eagle)
$60,000
Tyler Ice TAD Series, 500
gallons with 12-36' boomless
spray (Eagle)
$20,500
Small Tote Sprayer, 8-50'
booms (Tyler ICE)
$50,000
ASPT nozzle sprayer spraying
width of 15 meters. Tank
content 3,000 liters (Schmidt)
Average Cost1
$120,000
$40,000
1 - Yearly cost was calculated assuming a 6% interest rate and a 20 year loan term.
Sources:
Eagle - Mr. Trevor Winn, CA, CFO at Eagle Airfield (a division of Team Eagle Ltd), http://www.team-eagle.ca/.
Tyler ICE Div. of Wausau Equipment - Mr. Mark Kreutzfeldt. http://www.wausau-everest.com/
Schmidt - Mr. Rene Wender - Product Manager Airport equipment, http://www.aebi-schmidt.com.
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Section 10 - Technology Costs
Table 10-13 provides capital costs for potassium acetate storage tanks. Costs for three
types of storage tanks are presented: portable (frac), modular, and permanent. For smaller storage
needs, EPA assumed that an airport could use the chemical tote provided with the liquid deicer
purchase. EPA assumed that O&M costs for liquid storage are about the same as those for solid
storage. EPA assumes that a modular tank with a 50,000-gallon storage capacity will be the best
option for airports that use between 1,000 and 50,000 gallons of liquid airfield deicing chemical
each deicing season. A modular tank with a 100,000-gallon storage capacity will be the best
option for airports that use greater than 50,000 gallons of deicing chemical each season. EPA
assumed that airports using both urea and potassium acetate have sufficient liquid storage
available and therefore no costs for tanks are assigned to these airports.
Table 10-13. Storage Tank Capital Costs for Liquid Pavement Deicer
Tank Tvpc
Size (gallon)
Transaction Type
Cost
Cost for 2/3 of a year rental
Portable (Frac)
21,000
Rental
$45/day
$10,980
Portable (Frac)
21,000
Rental
$l,350/month
$10,800
Average Portable (Frac) Tank Cost
$10,890/yr
Tank Type
Size (gallon)
Transaction Type
Cost
Cost per gallon
Modular
50,000
Purchase
$40,000
$0.80
Modular
100,000
Purchase
$50,000
$0.50
Modular
245,000
Purchase
$80,000
$0.33
Modular
500,000
Purchase
$130,000
$0.26
Modular
1,000,000
Purchase
$225,000
$0.23
Modular
2,000,000
Purchase
$375,000
$0.19
Average Modular Tank Cost
$0.38
Tank Type
Size (gallon)
Transaction Type
Average Cost
Cost per gallon
Permanent
2,000,000
Purchase
2,000,000
$0.90
Permanent
4,000,000
Purchase
4,000,000
$0.70
Average Permanent Tank Cost
$0.80
The national average use of urea, based on EPA's airport questionnaire (U.S. EPA,
2006b) data for the three deicing seasons between 2002 and 2005, was 7,075,900 pounds per
year. Using the available range of application rates (small coverage area and large coverage area
for the same amount of urea) and statistical airport weighting values as determined by EPA, the
Agency estimated both capital costs for equipment (application equipment and storage tanks) and
chemical costs for a national switch from urea to potassium acetate. Table 10-14 lists the
annualized capital costs for application equipment and storage plus the annual cost for potassium
acetate for those airports in the scope of the final rule that indicated they use urea. Note that
airports that currently use potassium acetate for a portion of airfield deicing are assumed to have
both application equipment and storage available and therefore no capital costs are required.
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Table 10-14. Annualized Costs for In-Scope Airports to Change from Urea to Potassium
Acetate for Airfield Deicing
Airport ID
Annualized Capital
Equipment Cost1
($/yr 2006)
Predicted Potassium Acetate
Annual Cost
($/yr 2006)
Total Annualized Cost
(S/yr 2006)
1007
$30,654
$10,487
$41,141
1010
$0
$150,844
$150,844
1012
$0
$657,442
$657,442
1017
$0
$16,346
$16,346
1018
$0
$38,826
$38,826
1022
$0
$105,445
$105,445
1041
$27,125
$131
$27,256
1043
$0
$3,935
$3,935
1053
$49,879
$2,243
$52,122
1066
$0
$577,406
$577,406
1074
$30,654
$12,765
$43,419
1079
$0
$8,854
$8,854
1090
$0
$159,636
$159,636
1103
$31,536
$199,901
$231,436
1105
$31,536
$251,319
$282,855
1114
$0
$59,734
$59,734
1116
$0
$2,848
$2,848
1118
$30,654
$25,971
$56,625
1128
$0
$91,667
$91,667
1129
$0
$6,590
$6,590
1141
$0
$24,660
$24,660
1144
$0
$33,209
$33,209
1146
$30,654
$10,625
$41,278
1147
$30,654
$35,153
$65,807
Cost includes both application equipment and storage tanks.
10.4 Other ADF-Compliance-Related Costs
In addition to the costs associated with ADF stormwater collection and control and
airfield deicing chemical substitution, EPA also analyzed potential monitoring and reporting
costs for airports to comply with the various options. Specifically, EPA costed the model airports
to:
Assess ADF usage (in some instances, EPA assumed that the airport would not
need to assess usage);
Perform an engineering review of airport operations to determine and document
compliance with the percent ADF collection standard (for those that are in scope
of the analyzed collection requirements);
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Section 10 - Technology Costs
Perform annual ADF collection equipment/system inspections(for those who are
in scope of the analyzed collection requirements); and
Perform COD monitoring from an on-site treatment system (such as AFB
treatment) to demonstrate compliance with the COD standards (for those facilities
that are in scope of the analyzed option).
EPA's assumptions and methodology for estimating these costs are described below
along with a summary of the in-scope airports which EPA projected would incur these costs.
Table 10-15 presents these other compliance-related costs for each of the model airports
determined to be in the scope of the final rule.
10.4.1 Assessing ADF Usage from Airport Tenants
EPA assumed that many airports using ADF during typical winter seasons will need to
collect and compile ADF usage information from the airlines operating at the airport. EPA is
assuming that airport personnel will collect ADF usage data monthly from airport tenants and
will collate that data into a spreadsheet, which can be totaled each season to assess an annual
ADF usage for the entire airport. EPA is assuming that this activity will require 8 hours per
month and that ADF usage data is collected for 6 months of the year on average (based on
airports' reported deicing months). Costs associated with assessing ADF usage will therefore be:
8 hours/month x 6 deicing months/year x $35/hour labor rate = $l,680/year
The labor rate shown in the equation above is based on an average reported labor rate of
$33/hour obtained from responses to the airport questionnaire and an escalation rate of 7 percent
to adjust costs to a 2006 basis3. EPA adjusted the labor rate so that the labor costs for the
compliance activity will be on a similar-year basis as the other costs assessed by EPA.
EPA is assuming that only those airports that use less than 80,000 gallons of normalized
ADF per year would need to collect and assess total airport annual ADF. Rather than collect and
tabulate ADF usage, airports that use more than 80,000 gallons would likely certify that their
usage is above the cutoff specified in the analyzed option.
10.4.2 Determination of ADF Stormwater Collection Percentage
As part of the options evaluated by EPA in the final rule, airports with normalized ADF
use of >60,000 gallons/year would need to demonstrate that they achieve the analyzed collection
requirement. Airports would meet the collection requirement using the technologies costed by
EPA or through other means. EPA is assuming that airports would hire an engineering consultant
or firm to evaluate the airport's ADF usage data to calculate its available normalized ADF. The
engineering consultant would also evaluate information on the airport's pollution prevention,
deicing stormwater collection, and on-site treatment or alternative disposal.
3 From Bureau of Labor Statistics, Producer Price Index industry data for the airport industry. Increase from 2004 to
2006.
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Section 10 - Technology Costs
Table 10-15. Other Compliance-Related Costs by Airport
Airport ID
Airport
Total Annualized Compliance-
Related Costs
(S/vr 2006)
1001
Montgomery Rgnl (Dannelly Field)
$1,680
1003
Ketchikan Intl
$1,680
1004
Norfolk Intl
$1,680
1006
Chicago O'Hare Intl
$9,279
1007
Yeager
$1,680
1008
Tucson Intl
$1,680
1010
Fairbanks Intl
$9,279
1011
Lambert-St Louis Intl
$9,279
1012
Ted Stevens Anchorage Intl
$9,279
1014
Albuquerque Intl Sunport
$21,333
1015
Gulfport-Biloxi Intl
$1,680
1017
Austin Straubel International
$10,959
1018
Piedmont Triad International
$21,333
1019
Ontario Intl
$1,680
1020
Hartsfield - Jackson Atlanta Intl
$9,279
1021
Buffalo Niagara Intl
$9,279
1022
Fort Wayne International
$1,680
1023
Seattle-Tacoma Intl
$19,653
1024
Indianapolis Intl
$9,279
1026
Dallas/Fort Worth International
$9,279
1028
Denver Intl
$19,653
1029
La Guardia
$19,653
1031
Richmond Intl
$1,680
1032
Austin-Bergstrom Intl
$1,680
1033
Mc Carran Intl
$1,680
1034
Metropolitan Oakland Intl
$1,680
1035
San Diego Intl
$1,680
1036
Baltimore-Washington Intl
$9,279
1037
George Bush Intercontinental Arpt/Houston
$1,680
1040
Louis Armstrong New Orleans Intl
$1,680
1041
Glacier Park Intl
$1,680
1043
Ralph Wien Memorial
$1,680
1044
Roanoke Regional/Woodrum Field
$1,680
1045
Norman Y. Mineta San Jose International
$1,680
1046
Long Island Mac Arthur
$1,680
1050
Aspen-Pitkin Co/Sardy Field
$1,680
1052
Wilmington Intl
$1,680
1053
General Edward Lawrence Logan Intl
$19,653
1054
Jackson Hole
$1,680
1057
Will Rogers World
$1,680
1058
Gerald R. Ford International
$9,279
1059
Greater Rochester International
$9,279
1061
William P Hobby
$1,680
1062
Birmingham Intl
$1,680
1063
Evansville Regional
$1,680
1065
Albany Intl
$19,653
1066
Salt Lake City Intl
$9,279
1067
Helena Regional
$1,680
1068
Eppley Airfield
$19,653
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Section 10 - Technology Costs
Table 10-15 (Continued)
Airport ID
Airport
Total Annualized Compliance-
Related Costs
(S/vr 2006)
1069
Cleveland-Hopkins Intl
$9,279
1070
City of Colorado Springs Municipal
10,959
1074
South Bend Regional
$1,680
1075
Pensacola Regional
$1,680
1078
Nashville Intl
$19,653
1079
Manchester
$19,653
1080
Syracuse Hancock Intl
$9,279
1081
Bob Hope
$1,680
1083
Tampa Intl
$1,680
1084
Bismarck Municipal
$1,680
1086
Palm Beach Intl
$1,680
1087
El Paso Intl
$1,680
1088
Outagamie County Regional
$1,680
1089
John F Kennedy Intl
$19,653
1090
Boise Air Terminal/Gowen Fid
$10,959
1091
Rochester International
$1,680
1094
Boeing Field/King County Intl
$1,680
1095
Chicago Midway Intl
$9,279
1097
Lovell Field
$1,680
1099
Sacramento International
$1,680
1100
Toledo Express
$1,680
1101
Portland Intl
$19,653
1102
John Wayne Airport-Orange County
$1,680
1103
Juneau Intl
$1,680
1104
Nome
$1,680
1105
Spokane Intl
$10,959
1107
Pittsburgh International
$9,279
1108
Louisville Intl-Standiford Field
$9,279
1111
Port Columbus Intl
$19,653
1113
Cincinnati/Northern Kentucky International
$9,279
1114
Stewart Intl
$1,680
1115
Jacksonville Intl
$1,680
1116
Reno/Tahoe International
$21,333
1117
Cherry Capital
$1,680
1118
Bethel
$1,680
1119
Rickenbacker International
$1,680
1120
Rapid City Regional
$1,680
1121
Theodore Francis Green State
$9,279
1122
Southwest Florida Intl
$1,680
1123
James M Cox Dayton Intl
$9,279
1124
Des Moines Intl
$9,279
1126
Minneapolis/St Paul Intl/Wold-Chamberlain
$9,279
1128
Charlotte/Douglas Intl
$19,653
1129
Bradley Intl
$9,279
1130
San Antonio Intl
$1,680
1131
Wilkes-Barre/Scranton Intl
$1,680
1133
Phoenix Sky Harbor Intl
$1,680
1135
Lafayette Regional
$1,680
145
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Table 10-15 (Continued)
Airport ID
Airport
Total Annualized Compliance-
Related Costs
(S/vr 2006)
1136
General Mitchell International
$9,279
1137
Dallas Love Field
$1,680
1138
Detroit Metropolitan Wayne County
$9,279
1139
Philadelphia Intl
$9,279
1140
Memphis Intl
$19,653
1141
Ronald Reagan Washington National
$9,279
1142
Washington Dulles International
$19,653
1143
San Francisco International
$1,680
1144
Central Wisconsin
$1,680
1145
Newark Liberty Intl
$19,653
1146
Northwest Arkansas Regional
$1,680
1147
Raleigh-Durham Intl
$19,653
1148
Kansas City Intl
$9,279
EPA has estimated 264 hours and $28,424 total costs for a consulting firm to develop and
document an engineering assessment using airport-specific data. These costs include time for
project management, data analysis and evaluation of airport drawings, calculation of airport-
specific ADF collection, and preparation of a report. EPA developed the project elements and
estimated the average hourly rate for consulting engineers at $85/hour based on best professional
judgment. This cost is assumed to occur once each permit cycle (i.e., once every five years).
EPA assumed that all airports with >60,000 gallons/year normalized ADF usage would be
required to perform this analysis of the airport's ADF collection percent.
10.4.3 Annual ADF Collection Equipment/System Inspections
As part of the options evaluated by EPA for the final rule, airports could document
annual compliance with the collection standard by demonstrating that their selected BAT system
was properly maintained and operated. Airports could demonstrate that they were using those
technologies properly by annually inspecting the collection equipment and documenting that the
equipment was being maintained and used per the manufacturer's specifications.
EPA assumed that an annual inspection of ADF stormwater collection equipment/systems
would occur prior to the airport's deicing season and would include the following types of
activities as applicable:
Inspection of GCVs to ensure that they are maintained and ready for use as well
as any inspection of the vehicle vacuum system recommended by the
manufacturer (e.g., inspection of the vacuum pressure and/or nozzles); and
Inspection of the plug and pump or drainage diversion system to ensure that
system components are in good condition and working order (e.g., inspection and
exercising of shut-off values, inspection of balloon inserts).
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EPA assumed that 2 weeks of labor (80 hours total) would be required to perform these
activities on an annual basis:
80 hours/season x $35/hour labor rate = $2,800/year
EPA included these costs for all airports with >60,000 gallons/year normalized ADF
usage when evaluating the options with a collection standard in the final rule.
10.4.4 COD Monitoring of On-Site Treatment Systems
For this costing effort, EPA assumed that airports requiring additional ADF stormwater
collection and control to comply with the analyzed options, would treat the stormwater through
an on-site AFB treatment system. In addition, airports that were already achieving compliance
with the collection standard that use on-site treatment prior to direct discharge would need to
monitor compliance with the COD limitation. Most of the airports that currently collect ADF-
contaminated stormwater send it to a POTW or to off-site glycol recovery. However, for the
costing effort, EPA did not assume either POTW discharge or transfer to an off-site glycol
recovery facility would be a viable option for those airports requiring additional collection and
control. In assessing national costs, EPA assumed that airports requiring additional collection
and control would need to conduct ongoing monitoring of the effluent discharge point of the on-
site treatment system to ensure permit compliance.
To estimate AFB discharge monitoring costs, EPA assumed the following:
Airports would collect a daily 24-hour composite sample of treatment system
effluent for analysis of COD for each day the treatment system is operating;
Treatment systems would be operated continuously for 26 weeks per year (6
months);
Approximately 1 hour of labor is associated with sample collection and delivery
of the sample to the laboratory;
Labor costs for sample collection are $35/hr;4 and
Cost for COD analysis by the laboratory is $22/sample5 and includes the cost of
the sample container.
Using the assumptions above, EPA calculated the annual cost for monitoring the effluent
from an airport treatment system to be $10,374/year as follows:
Sample Analysis Cost ($/yr): 1 sample/day x 7 days/wk x 26 wks/yr x
$22/sample = $4,004;
Labor Cost ($/yr): 1 hr/day x 7 days/wk x 26 wks/yr x $35/hr = $6,370; and
Total Cost ($/yr): $4,004 + $6,370 = $10,374
EPA assumed that all model airports with normalized ADF use >60,000 gallons/year,
costed for additional collection and on-site treatment of ADF stormwater would monitor for
COD at the effluent discharge point from the on-site treatment system. In addition, EPA
4 Average labor costs from the airport questionnaire escalated to 2006 year basis.
5 Sample analysis costs obtained from EPA for analysis of COD samples by contract laboratory.
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evaluated all of the other model airports estimated as having >60,000 gallons/year normalized
ADF usage to determine which of those airports treat ADF stormwater on site and discharge the
effluent directly to U.S. surface waters. As a result, EPA also evaluated monitoring costs for the
following airports:
Washington Dulles International Airport;
Denver International Airport;
Albany International Airport; and
Nashville International Airport.
EPA assumed that all of the other model airports that would be required to meet the
collection standard do not directly discharge the available ADF required for collection.
10.5 Summary of Annualized Costs
Table 10-16 summarizes EPA's annualized costs for ADF collection and treatment, other
compliance-related costs, and urea substitution costs.
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Section 10 - Technology Costs
Table 10-16. Summary of EPA's Annualized Costs for ADF Collection and Treatment,
Airfield Deicing Urea Substitution, and Other Compliance-Related Costs
Airport
ID
Airport
Airport
Weighting
Factor
Annualized
Cost for 20%
Control and
Treatment
Scenario
(2006 $)
Annualized
Cost for 40%
Control and
Treatment
Scenario
(2006 $)
Total
Annualized
ADF-
Compliancc-
Related Costs
($/yr 2006)
Urea
Substitution
Total
Annualized
Cost
(S/yr 2006)
10011
Montgomery Regional
(Dannelly Field)
6.7013
$1,168
$1,168
$1,680
$0
10032
Ketchikan International
1.0000
NC
NC
$1,680
$0
1004
Norfolk International
1.0000
$0
$2,235,548
$1,680
$0
1006
Chicago O'Hare
International
1.0000
$0
$0
$9,279
$0
1007
Yeager
2.1508
$0
$0
$1,680
$41,141
1008
Tucson International
2.9997
$0
$1,069,305
$1,680
$0
1010
Fairbanks International
1.0000
$0
$0
$9,279
$150,844
1011
Lambert-St Louis
International
1.0000
$0
$0
$9,279
$0
1012
Ted Stevens Anchorage
International
1.0000
$0
$0
$9,279
$657,442
1014
Albuquerque International
Sunport
1.0000
$0
$6,269,926
$21,333
$0
1015
Gulfport-Biloxi International
5.8413
$0
$0
$1,680
$0
1017
Austin Straubel International
2.3269
$0
$0
$10,959
$16,346
1018
Piedmont Triad International
1.0000
$1,090,753
$8,121,534
$21,333
$38,826
10191
Ontario International
1.0000
$1,110
$1,110
$1,680
$0
1020
Hartsfield - Jackson Atlanta
International
1.0000
$0
$0
$9,279
$0
1021
Buffalo Niagara
International
1.0000
$0
$0
$9,279
$0
1022
Fort Wayne International
1.9682
$991,516
$3,272,310
$1,680
$105,445
1023
Seattle-Tacoma International
1.0000
$1,560,687
$3,863,913
$19,653
$0
1024
Indianapolis International
1.0000
$0
$0
$9,279
$0
1026
Dallas/Fort Worth
International
1.0000
$0
$0
$9,279
$0
1028
Denver International
1.0000
$0
$0
$19,653
$0
1029
La Guardia
1.0000
$2,976,443
$6,286,465
$19,653
$0
1031
Richmond International
1.0000
$0
$0
$1,680
$0
1032
Austin-Bergstrom
International
1.0000
$0
$0
$1,680
$0
1033
Mc Carran International
1.0000
$4,216
$4,216
$1,680
$0
1034
Metropolitan Oakland
International
1.0000
NC
NC
$1,680
$0
1035
San Diego International
1.0000
NC
NC
$1,680
$0
1036
Baltimore-Washington
International
1.0000
$0
$0
$9,279
$0
149
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Section 10 - Technology Costs
Table 10-16 (Continued)
Airport
ID
Airport
Airport
Weighting
Factor
Annualized
Cost for 20%
Control and
Treatment
Scenario
(2006 $)
Annualized
Cost for 40%
Control and
Treatment
Scenario
(2006 $)
Total
Annualized
ADF-
Compliancc-
Rclated Costs
($/yr 2006)
Urea
Substitution
Total
Annualized
Cost
(S/yr 2006)
1037
George Bush
Intercontinental
Airport/Houston
1.0000
$4,099
$4,099
$1,680
$0
1040
Louis Armstrong New
Orleans International
1.0000
NC
NC
$1,680
$0
1041
Glacier Park International
3.1409
$1,037,252
$1,266,155
$1,680
$27,256
1043
Ralph Wien Memorial
1.0000
$605,365
$707,178
$1,680
$3,935
1044
Roanoke
Regional/Woodrum Field
2.1921
$943,332
$4,095,087
$1,680
$0
10451
Norman Y. Mineta San Jose
International
1.0000
NC
NC
$1,680
$0
1046
Long Island Mac Arthur
1.9985
$0
$0
$1,680
$0
1050
Aspen-Pitkin Co/Sardy Field
4.7500
$0
$0
$1,680
$0
1052
Wilmington International
6.0388
$654,946
$3,131,737
$1,680
$0
1053
General Edward Lawrence
Logan International
1.0000
$4,860,377
$6,659,582
$19,653
$52,122
1054
Jackson Hole
4.3500
$0
$0
$1,680
$0
1057
Will Rogers World
1.0000
$986,385
$2,675,571
$1,680
$0
1058
Gerald R. Ford International
1.5862
$0
$0
$9,279
$0
1059
Greater Rochester
International
1.0000
$0
$0
$9,279
$0
1061
William P Hobby
1.0000
$0
$0
$1,680
$0
10621
Birmingham International
2.8410
$2,675
$2,675
$1,680
$0
1063
Evansville Regional
5.1042
$846,931
$1,609,927
$1,680
$0
1065
Albany International
1.0000
$0
$0
$19,653
$0
1066
Salt Lake City International
1.0000
$0
$0
$9,279
$577,406
1067
Helena Regional
4.2000
$0
$0
$1,680
$0
1068
Eppley Airfield
1.0000
$1,250,502
$2,132,279
$19,653
$0
1069
Cleveland-Hopkins
International
1.0000
$0
$0
$9,279
$0
1070
City of Colorado Springs
Municipal
1.7414
$0
$0
10,959
$0
1074
South Bend Regional
2.1417
$0
$0
$1,680
$43,419
1075
Pensacola Regional
3.9341
$0
$0
$1,680
$0
1078
Nashville International
1.0000
$0
$0
$19,653
$0
1079
Manchester
1.0000
$1,600,420
$1,995,084
$19,653
$8,854
1080
Syracuse Hancock
International
1.0000
$0
$0
$9,279
$0
1081
Bob Hope
1.0000
NC
NC
$1,680
$0
1083
Tampa International
1.0000
NC
NC
$1,680
$0
150
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Section 10 - Technology Costs
Table 10-16 (Continued)
Airport
ID
Airport
Airport
Weighting
Factor
Annualized
Cost for 20%
Control and
Treatment
Scenario
(2006 $)
Annualized
Cost for 40%
Control and
Treatment
Scenario
(2006 $)
Total
Annualized
ADF-
Compliancc-
Rclated Costs
($/yr 2006)
Urea
Substitution
Total
Annualized
Cost
(S/yr 2006)
1084
Bismarck Municipal
3.8679
$770,509
$1,215,970
$1,680
$0
1086
Palm Beach International
1.0000
$0
$0
$1,680
$0
1087
El Paso International
3.0457
$0
$0
$1,680
$0
1088
Outagamie County Regional
2.4841
$1,011,102
$2,412,516
$1,680
$0
1089
John F Kennedy
International
1.0000
$3,215,317
$10,136,241
$19,653
$0
1090
Boise Air Terminal/Gowen
Fid
1.5043
$0
$0
$10,959
$159,636
1091
Rochester International
3.1749
$0
$0
$1,680
$0
1094
Boeing Field/King County
International
5.8985
$0
$0
$1,680
$0
1095
Chicago Midway
International
1.0000
$0
$0
$9,279
$0
10971
Lovell Field
4.9996
$3,745
$3,745
$1,680
$0
10991
Sacramento International
1.0000
NC
NC
$1,680
$0
1100
Toledo Express
2.0917
$0
$1,767,861
$1,680
$0
1101
Portland International
1.0000
$0
$2,792,934
$19,653
$0
1102
John Wayne Airport-Orange
County
1.0000
NC
NC
$1,680
$0
1103
Juneau International
1.0000
$957,795
$2,343,519
$1,680
$231,436
1104
Nome
1.0000
$618,441
$1,904,296
$1,680
$0
1105
Spokane International
1.5192
$0
$0
$10,959
$282,855
1107
Pittsburgh International
1.0000
$0
$0
$9,279
$0
1108
Louisville International-
Standiford Field
1.0000
$0
$0
$9,279
$0
1111
Port Columbus International
1.0000
$2,029,946
$4,321,331
$19,653
$0
1113
Cincinnati/Northern
Kentucky International
1.0000
$0
$0
$9,279
$0
1114
Stewart International
2.8661
$0
$0
$1,680
$59,734
1115
Jacksonville International
1.0000
$0
$0
$1,680
$0
1116
Reno/Tahoe International
1.0000
$0
$1,614,875
$21,333
$2,848
1117
Cherry Capital
3.5400
$0
$0
$1,680
$0
1118
Bethel
1.0000
$643,331
$1,936,511
$1,680
$56,625
1119
Rickenbacker International
4.3659
$710,969
$1,433,955
$1,680
$0
1120
Rapid City Regional
3.1082
$838,073
$4,548,952
$1,680
$0
1121
Theodore Francis Green
State
1.0000
$0
$0
$9,279
$0
1122
Southwest Florida
International
1.0000
$0
$0
$1,680
$0
151
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Section 10 - Technology Costs
Table 10-16 (Continued)
Airport
ID
Airport
Airport
Weighting
Factor
Annualized
Cost for 20%
Control and
Treatment
Scenario
(2006 $)
Annualized
Cost for 40%
Control and
Treatment
Scenario
(2006 $)
Total
Annualized
ADF-
Compliancc-
Rclated Costs
($/yr 2006)
Urea
Substitution
Total
Annualized
Cost
(S/yr 2006)
1123
James M Cox Dayton
International
1.0000
$0
$0
$9,279
$0
1124
Des Moines International
1.6211
$0
$0
$9,279
$0
1126
Minneapolis/St Paul
International/Wold-
Chamberlain
1.0000
$0
$0
$9,279
$0
1128
Charlotte/Douglas
International
1.0000
$1,574,890
$2,111,996
$19,653
$91,667
1129
Bradley International
1.0000
$0
$0
$9,279
$6,590
1130
San Antonio International
1.0000
$780,240
$5,064,195
$1,680
$0
1131
Wilkes-Barre/Scranton
International
2.6815
$971,556
$1,476,180
$1,680
$0
11331
Phoenix Sky Harbor
International
1.0000
NC
NC
$1,680
$0
11351
Lafayette Regional
6.6425
$1,536
$1,536
$1,680
$0
1136
General Mitchell
International
1.0000
$0
$0
$9,279
$0
1137
Dallas Love Field
1.0000
$0
$0
$1,680
$0
1138
Detroit Metropolitan Wayne
County
1.0000
$0
$0
$9,279
$0
1139
Philadelphia International
1.0000
$0
$0
$9,279
$0
1140
Memphis International
1.0000
$1,740,377
$3,651,474
$19,653
$0
1141
Ronald Reagan Washington
National
1.0000
$0
$0
$9,279
$24,660
1142
Washington Dulles
International
1.0000
$0
$0
$19,653
$0
1143
San Francisco International
1.0000
$0
$0
$1,680
$0
1144
Central Wisconsin
3.0156
$952,550
$1,451,583
$1,680
$33,209
1145
Newark Liberty Intl
1.0000
$5,366,144
$9,674,611
$19,653
$0
1146
Northwest Arkansas
Regional
1.8782
$873,730
$1,644,615
$1,680
$41,278
1147
Raleigh-Durham Intl
1.0000
$1,294,323
$4,254,332
$19,653
$65,807
1148
Kansas City Intl
1.0000
$0
$0
$9,279
$0
NC - Not Calculated.
1 Airport is in a warm climate and uses either no ADF or small amounts of ADF, and EPA assumes the airport will
contract out all ADF removal and disposal operations.
2 Airport was sent an airport questionnaire but did not respond.
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10.6 References
ACRP Fact Sheets, ACRP Report 14, Deicing Practices, Transportation Research Board,
Sponsored to Federal Aviation Administration.
Airport Council International - North America Comments on EPA's Proposed Effluent
Limitations Guidelines and New Source Performance Standards for the Airline Industry.
ERG. 2006. Memorandum from Lou Nadeau and Cal Franz (ERG) to Maria Smith (U.S. EPA).
Results of Airport Survey Sample Draw. (March 17). DCN AD01234.
ERG. 2007a. Personnel communication (email) between Mary Willett (ERG) and Roy
Fuhrmann, Minneapolis/St. Paul International Airport. (May 3). DCN AD00872.
ERG. 2007b. Personnel communication (email) between Mary Willett (ERG) and Mark Sober,
Albany International Airport. (May 3). DCN AD00865.
ERG. 2007c. Personnel communication (email) between Mary Willett (ERG) and Mark Sober,
Albany International Airport. (June 27). DCN AD00866.
ERG. 2007d. Personnel communication (email) between Mary Willett (ERG) and Akron-Canton
International Airport. (May 3). DCNs AD00863 and AD00864.
ERG. 2008. Memorandum from Cortney Itle and Robyn Reid (ERG) to Airport Deicing
Administrative Record. Estimated Annual Costs for airports with Limited ADF Use. (February).
DCN ADO 1261.
ERG. 2010. Memorandum from Steve Strackbein and Mary Willett (ERG) to Airport Deicing
Administrative Record. Estimated Capital and Operation and Maintenance Costs for Glycol
Collection Vehichle Operation. (October 8). DCN AD01249.
ERG. 2010a. Memorandum from Steve Strackbein and Mary Willett (ERG) to Brian D'Amico
and Eric Strassler (U.S. EPA). Estimated Costs for Transition to Liquid Airfield Deicing
Application from Solid Airfield Deicing. (October 8). DCN AD01252.
ERG. 2010b. Memorandum from Mary Willett (ERG) to the Airport Deicing Administrative
Record. Estimated Compliance-Related Costs for the Final Airport Deicing Rulemaking.
(November 17). DCN AD001255.
ERG. 2010c. Memorandum from Mark Briggs (ERG) to the Airport Deicing Administrative
Record. Estimated Capital and O&M Costs for Additional Stormwater Piping. (July 26). DCN
AD01253.
ERG. 2010d. Memorandum from Mark Briggs and Mary Willett (ERG) to Airport Deicing
Administrative Record. Estimated Land Requirements and Opportunity Costs for the Anaerobic
Fluid Bed Treatment System and ADF Stormwater Storage Tanks. (October). DCN AD01251.
ERG. 2011. Memorandum from Cortney Itle and Mary Willett (ERG) to Brian D'Amico (U.S.
EPA). ADF Collection and Control Efficiency Review. (June 15). DCN ADO 1270.
153
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Section 10 - Technology Costs
Google Earth Geographical Mapping System, 2007.
McQueen, R., and Arendt, T. Development of a Deicer Management System for Akron-Canton
Airport.
RS Means Construction Cost Data, 68th Annual Edition, 2010.
Switzenbaum, et al. 1999. Workshop: Best Practices for Airport Deicing Stormwater. DCN
AD00893.
Transport Canada, Transportation Development Center. "Laboratory Testing of Tire Friction
Under Winter Conditions (TP 13392E)." May 1998.
USEPA. 2006a. Final Engineering Site Visit Report for General Mitchell International Airport,
Milwaukee, WI. U.S. Environmental Protection Agency. Washington, D.C. (June 7) DCN
AD00772.
USEPA. 2006b. Airport Deicing Questionnaire. U.S. Environmental Protection Agency.
Washington, D.C. DCN AD00354.
USEPA. 2006c. Final Sampling Episode Report for Albany International Airport. U. S.
Environmental Protection Agency. Washington, D.C. (July 19). DCN AD00842.
USEPA. 2010. Airport Deicing Costing Database. U.S. Environmental Protection Agency.
Washington, D.C. DCN AD01256.
USEPA. 2012. Economic Analysis for Final Effluent Limitation Guidelines and Standards for the
Airport Deicing Category. EPA-821-R-12-004. (March). DCN AD01280.
U.S. Department of Commerce. National Oceanic and Atmospheric Administration (NOAA)
National Climate Data Center.
U.S. Federal Aviation Administration (FAA) National Flight Data Center.
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11. Regulatory Options Considered And Selected For basis Of Final
Regulation
This section presents the technology options evaluated by EPA for the Airport Deicing
Category as the basis for the final effluent limitation guidelines and standards. It also describes
the methodology for EPA's selection of the final technology options. Specifically, this section
describes the basis for BAT and NSPS; as detailed in this section, EPA is not establishing BPT,
BCT, PSES or PSNS at this time.
The regulatory option selected provides the technology basis of the final effluent
limitation guidelines and standards (ELGs). Entities subject to these regulations would not be
required to use the specific technologies selected by EPA to establish the ELGs. Rather, an entity
could choose to use any combination of operational changes, pollution prevention, and treatment
technologies to comply with the limitations and standards, provided the limitations and standards
are achieved.
11.1 BPT and BCT
EPA considered whether in this rule it was necessary to establish BPT limits, given that
pavement deicers will be controlled at the BAT level. The Agency concluded that it is not
necessary to promulgate BPT effluent limitation guidelines for the Airport Deicing Category,
given that the BAT collection and treatment requirements would be at least as stringent as BPT
requirements. Similarly, EPA is not establishing BCT limitations for this industry because the
same wastestream that would be controlled by BCT is being controlled by BAT.
11.2 BAT
For airfield deicing (runways), EPA concludes that the "best available technology" for
reducing ammonia in wastewater discharges from airfields consists of using deicing products not
containing urea, instead of those that contain urea. The administrative record for this rulemaking
shows that products without urea are widely available in the industry, and in fact are already in
use at a majority of airports across the country. In addition, using only deicers without urea is
economically achievable by the industry, as explained in the discussion of EPA's economics
analysis below.
To comply with this limitation, a discharger subject to the rule must either certify
annually that it does not use airfield deicing products that contain urea or airfield pavement
discharges must achieve a numeric limitation for ammonia as nitrogen of 14.7 mg/L. Table 11-1
presents the in-scope airports impacted by EPA's BAT standards and EPA's estimates of costs
and loading removals associated with the final rule.
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Table 11-1. Final Rule BAT Annualized Costs and Load Removals for In-Scope Airports
Airport
ID
Airport
Airport
Weighting
Factor
Urea Substitution
Total Annualized
Cost
($/yr 2006)
Potential
Load
Reduction
(lbs of COD)
Potential Load
Reduction
(lbs of
Ammonia)
1007
Yeager
2.1508
$41,141
42,471
15,572
1010
Fairbanks Intl
1.0000
$150,844
512,432
187,883
1012
Ted Stevens Anchorage Intl
1.0000
$657,442
3,881,674
1,423,212
1017
Austin Straubel Intl
2.3269
$16,346
69,240
25,387
1018
Piedmont Triad Intl
1.0000
$38,826
143,028
52,441
1022
Fort Wayne Intl
1.9682
$105,445
440,728
161,593
1041
Glacier Park Intl
3.1409
$27,256
514
189
1043
Ralph Wien Memorial
1.0000
$3,935
15,435
5,659
1053
General Edward Lawrence Logan
Intl
1.0000
$52,122
15,769
5,782
1066
Salt Lake City Intl
1.0000
$577,406
1,730,588
634,519
1074
South Bend Regional
2.1417
$43,419
50,070
18,358
1079
Manchester
1.0000
$8,854
56,851
20,844
1090
Boise Air Terminal/Gowen Field
1.5043
$159,636
416,584
152,740
1103
Juneau Intl
1.0000
$231,436
737,779
270,506
1105
Spokane Intl
1.5192
$282,855
768,648
281,824
1114
Stewart Intl
2.8661
$59,734
234,299
85,905
1116
Reno/Tahoe Intl
1.0000
$2,848
17,265
6,330
1118
Bethel
1.0000
$56,625
103,927
38,105
1128
Charlotte/Douglas Intl
1.0000
$91,667
231,340
84,821
1129
Bradley Intl
1.0000
$6,590
25,849
9,478
1141
Ronald Reagan Washington
National
1.0000
$24,660
120,391
44,141
1144
Central Wisconsin
3.0156
$33,209
190,526
69,856
1146
Northwest Arkansas Regional
1.8782
$41,278
27,782
10,186
1147
Raleigh - Durham Intl
1.0000
$65,807
97,753
35,841
Source: Airport Deicing Loadings Database (EPA, 2010).
11.2.1 Airfield Deicing: Product Substitution of Pavement Deicers Containing Urea
In general, airports discharge airfield pavement deicing chemicals without treatment, due
to the difficulty and expense of collecting and treating the large volumes of contaminated
stormwater generated on paved airfield surfaces. EPA is not aware of an available means to
control these pollutants by collecting and using a conventional, end-of-pipe treatment system. It
is possible, however, to reduce or eliminate certain pollutants by modifying deicing practices,
such as using alternative chemical deicing products. In particular, EPA has identified ammonia
and COD from airfield deicing as pollutants of concern, and both of these pollutants are a by-
product of pavement deicers containing urea. Accordingly, to address discharges of ammonia
from airfield pavement, EPA identified one candidate for best available technology: product
substitution, or discontinuing the use of pavement deicers containing urea and using alternative
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pavement deicers instead. EPA found that using deicers without urea is the best available
technology for reducing discharges of ammonia from pavement deicing because it is safe,
technologically feasible, and available across the industry. Currently only about 10 percent of
chemical pavement deicers applied nationwide contain urea. The most widely used pavement
deicer is potassium acetate, which represents 63 percent of all chemical pavement deicers applied
nationwide.
11.2.2 Aircraft Deicing: ADF Collection Requirements and Effluent Limitations
11.2.2.1 Available ADF Collection Technologies and Scope
EPA is not aware of an available and economically achievable technology that is capable
of capturing 100 percent of the sprayed ADF. As described above, the available technologies for
collecting ADF are glycol collection vehicles, plug and pump equipment, and CDPs. EPA
estimates these technologies collect 20 percent, 40 percent, and 60 percent of available ADF,
respectively.
After considering the comments provided on the proposed regulation and reviewing the
information in its record, EPA is not establishing a 60 percent ADF collection requirement based
on CDPs for BAT. First, in response to FAA's concerns about the exclusive use of deicing pads
for aircraft deicing, EPA contacted a number of Large Hub airports that currently use CDPs.
EPA found the current percentage of flights for which these airports use the CDPs ranges from
50 to 95 percent. The airports explained that various operational or weather-related issues may
make deicing pad use for all flights cumbersome if not impossible (i.e., severe system-wide
delays), and require them to deice at the gate in some circumstances. EPA shares the
commenters' and FAA's concerns that moving to exclusive use of CDPs for all deicing might
lead to operational issues and delays. EPA, in discussions with FAA, attempted to craft
regulatory provisions to allow an airport limited ability to bypass the use of a centralized pad to
avoid these circumstances. However, limited data on the site-specific nature of this industry left
EPA unable to develop regulatory provisions that would give airports the flexibility they need to
avoid significant operational issues and delays. Second, based on public comments and
information from FAA, EPA is concerned that some large airports critical to efficient air traffic
operations in this country are space (land) constrained and that building well-located CDPs for
all deicing operations at these airports is likely not feasible for that reason. At the time of the
proposal, EPA estimated that 14 airports would be subject to the 60 percent collection
requirement. Because the data in EPA's record indicate that many of these airports currently
meet this requirement, EPA estimated approximately seven airports would likely need to install
pads as a result of the proposed requirement. Of these seven airports, four are Large Hubs that,
over years of expansions and other improvements, have already built out the majority of the land
available to them. EPA has concluded that the lack of remaining available land, coupled with
their existing layouts, has left these airports in a position where they cannot construct a CDP that
conforms to FAA's Advisory Circulars on deicing pad design (e.g., in a location that aircraft can
travel to safely and efficiently to conduct deicing operations).
Therefore, for the final rule, EPA has not established a 60 percent ADF collection
requirement, which would have been based on identifying centralized deicing facilities as BAT
for 100 percent of aircraft departures. Because of land constraints and the other reasons
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discussed above, EPA finds that centralized deicing facilities should not be identified as BAT for
this nationwide rulemaking.
EPA then considered the other two technologies described in the proposed rule as a
possible basis of BAT for aircraft deicing discharges for the final rule: 40 percent ADF
collection requirement based on plug and pump with GCVs and 20 percent ADF collection
requirement based on GCVs. With either of these collection technologies, as was the case in the
proposed rule, EPA also included numeric COD limitations for direct discharges of collected
ADF based on anaerobic treatment.
11.2.3 Options Consideredfor Today '.s Final Regulation for Identification of BATfor
ADF Collection and Discharge Requirements
Using the technology bases identified above for airfield and aircraft deicing discharges,
EPA developed three primary options for the final rule. All three of these options have the same
airfield pavement deicing discharge requirements based on product substitution of deicers that do
not contain urea, but would vary the approach to control aircraft deicing discharges:
Option 1: 40 percent ADF collection requirement for large and medium ADF
users (based on plug and pump with GCVs); numeric COD limitations for direct
discharges of collected ADF (based on anaerobic treatment);
Option 2: 40 percent ADF collection requirement for large ADF users (based on
plug and pump with GCVs) and 20 percent ADF collection requirement for
medium ADF users (based on GCVs); numeric COD limitations for direct
discharges of collected ADF (based on anaerobic treatment); and
Option 3: Site-specific aircraft deicing discharge controls: Do not establish
effluent limitation guidelines in the final rule for aircraft deicing discharges, but
instead, leave the determination of BAT requirements for each airport to the
discretion of the permit writer on a case-by-case, "best professional judgment"
basis based on site-specific conditions.
Under the first option, in addition to the airfield pavement requirements, all airports that
use greater than or equal to 60,000 gallons of normalized ADF annually would be required to
collect 40 percent of available ADF based on plug and pump with GCV technologies. In the
proposed rule, EPA considered but did not identify this as its lead option because it found its
costs to be comparable to those of CDPs, while CDPs collect more ADF. In the proposed rule,
EPA therefore identified CDPs as BAT. Because EPA no longer considers CDPs to be the best
available technology for existing airports, the plug and pump with GCV option represents the
technology, among those that remain under consideration for the final rule, that would collect
the most ADF.
Under the second option, in addition to the airfield pavement requirements, all airports
that use greater than or equal to 60,000 gallons of normalized ADF annually but less than
460,000 gallons of normalized ADF ("medium ADF users," estimated to be 42 airports) would
be required to collect 20 percent of available ADF based on GCVs, and airports that use more
than 460,000 gallons of normalized ADF ("large ADF users," estimated to be 14 airports) would
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be required to collect 40 percent of available ADF based on the use of plug and pump with GCV
technology.
Under both Options 1 and 2, facilities would need to meet numeric effluent limits for
COD for the collected ADF prior to commingling it with other wastestreams prior to discharge.
Under the third option, EPA would establish national deicing discharge controls for
airfield pavement deicing only. BAT limitations for aircraft deicing discharge would continue to
be established by the permitting authority on a case-by-case basis.
11.2.4 BA T Options Selection
EPA is selecting Option 3 as best available technology for controlling airport deicing
discharges. EPA has determined the best available technology for controlling airfield pavement
discharges is product substitution. The administrative record for this rulemaking shows that
products without urea are widely available in the industry, and in fact are already in use at a
majority of airports across the country.
With respect to aircraft deicing discharge controls, EPA's record demonstrates that ADF
collection and associated treatment technologies are technically feasible for many airports. Data
supplied from the industry through EPA's nationally representative survey of airports indicates
that dozens of airports currently use GCVs and plug and pump collection systems as well as
myriad pollution prevention technologies and practices, ranging from alternative means of
applying ADF (e.g., forced air nozzles) to alternate deicing technologies (e.g., infrared deicing).
Thus, this industry has numerous technology options available for mitigating the pollutants
associated with aircraft deicing activities.
However, EPA concludes that none of the ADF collection technologies considered for
the final rule represents the "best available technology" for the entire category. Rather, EPA
concludes that best available technology determinations should continue to be made on a site-
specific basis because such determinations appropriately consider local operational constraints
(e.g., traffic patterns), land availability, safety considerations, and potential impacts to flight
schedules. Based on the information in its administrative record, EPA cannot identify with
precision the extent to which such limitations may preclude any particular airports from
implementing the technologies that it considered for BAT control of aircraft deicing discharges.
However, the record demonstrates that such limitations exist and are not isolated or insignificant.
More specifically, comments provided by airport and airline industry on the proposed regulation
raised concerns about the impacts that ADF collection technologies may have on safety and
operations at airports across the country. They also commented on the lack of available space at
many land-constrained airports for ADF collection and treatment technologies. EPA reviewed
the information submitted in comments, subsequent information provided by industry, and
information obtained from site visits to thoroughly evaluate these concerns. After reviewing this
information, EPA agrees with commenters that, while many airports likely are able to implement
some form of collection or pollution prevention technologies to mitigate pollutant discharges
associated with aircraft deicing, other airports may not be able to implement specific
technologies due to space, safety, and operational considerations. This became particularly
apparent after reviewing questionnaire responses from some of the airports at which EPA also
conducted site visits. EPA found that its "model facility" approach was not a suitable substitute
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for a detailed analysis of the site constraints at each airport. For example, a permit authority may
need to evaluate existing traffic patterns at an airport, not only of the aircraft, but also of the
service vehicles, to determine if additional collection vehicles would lead to unacceptable safety
concerns. With respect to land constraints, without detailed airport schematics or conducting a
detailed site visit at each airport, EPA cannot determine if adequate space exists to incorporate
the specific treatment and collection technologies evaluated as the basis for the final rule.
Additionally, industry, and FAA in particular, have expressed concerns about possible
delays and economic impact that could result from using plug and pump and GCVs, both at
specific airports and nationwide. EPA agrees that delays must be a factor in considering today's
possible requirements and recognizes that such delays fundamentally affect U.S and international
business and recreational interests.
Airplane deicing activities, by their nature, occur during freezing precipitation events. For
some airports, even small amounts of precipitation can lead to delayed aircraft departures - even
without deicing activity and/or ADF collection and treatment. As such, it is difficult to determine
if delays at an airport during inclement weather are associated with the weather, the ADF
collection and treatment technologies, or both. Further, even small delays at certain hub airports
have a ripple effect that can affect the entire national air traffic schedule.
Some airports have identified procedures to mitigate or prevent delays associated with
aircraft deicing discharge controls, but these approaches may not be applicable nationwide.
Further, the extent of delays deemed acceptable is likely to vary by airport. As with land
constraints, the confounding factors that need to be considered to evaluate possible delays that
may be associated with the technology bases do not lend themselves to a national determination
using a model facility approach. Further, EPA does not have detailed site-specific information to
evaluate delays on an airport-by-airport basis.
While the facts stated above do not preclude the ability of an airport to collect and treat
spent ADF, they do illustrate why EPA did not select any of the technologies considered as BAT
for the final rule, and why a site-specific BAT determination for ADF collection and treatment
requirements is the proper approach.
Therefore, for the reasons identified above, EPA determined Option 3 is the only
technologically feasible and available option considered for today's final BAT requirements.
Option 3 would remove 4.4 million pounds of ammonia and 12 million pounds of COD, with a
projected annual cost of $3.5 million. The costs of Option 3 are reasonable in terms of the
pollutant reductions achieved ($0.21/lb). Further, as discussed in more detail in the preamble to
the final rule, EPA finds Option 3 is economically achievable. In addition, EPA examined the
non-water-quality impacts anticipated from compliance with Option 3 requirements and found
none or only very minor impacts in comparison to typical industry energy use, emissions
generation, and sludge generation. Therefore, based on all the factors above, EPA is identifying
Option 3 as BAT and has based today's final rule on the Option 3 BAT requirements.
11.3 NSPS
For today's final rule, EPA evaluated "best available demonstrated control technologies"
for purposes of setting new source performance standards under CWA section 306. Section 306
directs EPA to promulgate NSPS "for the control of the discharge of pollutants which reflects the
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greatest degree of effluent reduction which the Administrator determines to be achievable
through application of the best available demonstrated control technology, processes, operating
methods, or other alternatives, including, where practicable, a standard permitting no discharge
of pollutants." Congress envisioned that new treatment systems could meet tighter controls than
existing sources because of the opportunity to incorporate the most efficient processes and
treatment systems into the facility design. As a result, NSPS should represent the most stringent
controls attainable through the application of the best available demonstrated control technology
for all pollutants (that is, conventional, nonconventional, and priority pollutants).
After careful consideration of the information in its record, EPA is today promulgating
the same NSPS requirements for both airfield pavement deicing discharges and airplane deicing
discharges as it proposed. However, the applicability of the NSPS requirements has changed and
EPA has revised the new source definition in the rule to mean new airports only and exclude new
runways at existing airports. EPA determined that, just as with existing sources, all new sources
would be able to substitute airfield deicing products without urea for those with urea.
Furthermore, product substitution represents the greatest ammonia level reduction among the
available technologies considered. Accordingly, EPA identifies product substitution of non-urea-
containing airfield deicers as the best demonstrated available control technology for all new
sources. As with BAT, there would be two alternatives for meeting this effluent limitation: either
a certification requirement or a numeric limit on ammonia for all direct discharges of the
stormwater from the airfields.
The final rule NSPS also includes a 60 percent collection (based on CDP technology) and
control requirement for ADF-contaminated stormwater at new airports anticipated to conduct
significant aircraft deicing activities. EPA, in consultation with FAA, finds that safety, space,
and operational constraints that may be present at existing airports for the collection and
treatment technologies discussed in the final rule (CDPs, plug and pump with GCVs, and GCVs
alone), would not apply to new airports. New airports can be designed to minimize space and
logistical constraints identified for retrofits at existing airports. Further, among the collection
technologies for ADF that EPA considered, CDPs collect the greatest level of available ADF.
Meeting the new source requirements would not be an economic barrier to entry for new airports,
as the cost of new airport construction, even small airports, is significantly greater than the costs
associated with collection and/or treatment of spent deicing fluids (see DCN AD01260 for
further detail). Moreover, according to FAA, when designed properly, CDPs often improve
traffic flow and reduce delays associated with aircraft deicing. When designing a new airport, the
local operating agency plans the site for all needed facilities, such as runways, taxiways,
terminal(s) and other components needed to comply with safety and environmental requirements,
and this includes deicing facilities. See FAA Advisory Circular 150/5070-6B, "Airport Master
Plans," and FAA Advisory Circular 150/5300-14B, "Design of Aircraft Deicing Facilities," DCN
AD00852. Finally, EPA notes that it did not receive any negative comments on its proposal to
base the NSPS ADF collection requirements on CDPs. See DCNs AD01260, AD01284, and
AD01335for EPA's rationale for setting NSPS applicability.
As a point of clarification, EPA is promulgating the same numeric COD limitations for
collected ADF that is discharged directly from new sources as were proposed. The technology
basis of the COD limitations, AFB, is available to new airportsand achieves the greatest level of
pollutant removals of those technologies considered during the development of this regulation.
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Further, installing and using this technology is not economically a barrier to entry for new
airports.
11.4 PSES and PSNS
EPA is not promulgating PSES and PSNS for the Airport Deicing Category. Although
some airports in the United States discharge ADF-contaminated storm water to POTWs, EPA
received no comments or other information indicating that POTWs currently have problems of
pollutant pass-through, interference, or sludge contamination stemming from these discharges
that would necessitate the promulgation of national categorical pretreatment standards.
Like the biological treatment system that forms the basis for today's COD limitations,
POTWs typically use biological treatment systems and are similarly designed to remove organic
pollutants that contribute to COD and/or BOD5. In general, POTWs can achieve comparable
removals to the BAT technology basis. However, some airports and POTWs may need to make
operational adjustments to process the wastewater effectively while avoiding POTW upset. EPA
received a comment about the Downriver Treatment Facility in Detroit, Michigan, which accepts
ADF wastewater from the Detroit Metropolitan Wayne County Airport. The treatment plant
experienced viscous bulking due to a nutrient imbalance that occurred during the months that
ADF was accepted. The issue was resolved by removing phosphorus at a later stage in the
treatment plant system, rather than from the raw wastewater. The airport also made significant
changes to segregate their deicing stormwater, capture and recycle the most concentrated ADF-
contaminated stormwater, and control the amount and concentration of stormwater discharged to
the POTW.
EPA is aware that high concentration or "slug" discharges of deicing stormwater can
create POTW upset. The national pretreatment program regulations specifically prohibit
industrial users from discharging high concentrations of oxygen-demanding pollutants to
POTWs if they cause interference to the POTW (see 40 CFR 403.5(b)(4)). Under 40 CFR
403.5(c), control authorities may set and enforce "local limits" for airport discharges to POTWs
to implement the prohibitions listed in ง 403.5(b)(4). This provision ensures that any potential
limits would protect against POTW interference by the oxygen-demanding pollutants in airport
deicing discharges. See "Local Limits Development Guidance," document no. EPA 833-R-04-
002A, July 2004, available on EPA's website at:
http://cfpub.epa.gov/npdes/pretreatment/pstandards.cfm.
As a result, many airports that discharge to POTWs have airport-specific requirements
on allowable BOD5 or COD discharge loadings per day to the receiving POTWs. Airports
usually meet this requirement by storing deicing stormwater in ponds or tanks and metering the
discharge to meet the POTW permit loading requirements.
11.5 References
ERG. 2008. Memorandum from Cortney Itle (ERG) to Brian D'Amico (U.S. EPA). Airport
Deicing Loading Calculations. (April 17). DCN ADO 1140.
ERG. 2012. Memorandum from Mary Willett and Cal Franz (ERG) to Brian D'Amico (U.S.
EPA). NSPS Feasibility - ADF Collection and Treatment Requirements. (January 23). DCN
AD01284.
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USEPA. 2009. Economic Analysis for Proposed Effluent Limitation Guidelines and Standards
for the Airport Deicing Category. U.S. Environmental Protection Agency. Washington, D.C.
EPA 821-R-09-005. DCN ADO 1196.
USEPA. 2010. Airport Deicing Loadings Database. U.S. Environmental Protection Agency.
Washington, D.C. DCN AD01257.
USEPA. 2012. Memorandum from Brian D'Amico (U.S. EPA) to Record. Final Rule Barrier to
Entry Analysis for New Source Performance Standards for Airport Deicing. (February 8). DCN
AD01260.
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12. Non-Water Quality Impacts
Sections 304(b) and 306 of the CWA require EPA to consider non-water-quality
environmental impacts (including energy requirements) associated with effluent limitation
guidelines and standards. As explained in the preamble to the final rule, EPA evaluated three
regulatory options for today's rule. The first two options are based on technologies to control
aircraft and airfield deicing discharges, while the the third option is based on technology solely
to control airfield deicing discharges.
In considering non-water quality environmental impacts, EPA first analyzed the potential
impact of the Option 1 technologies on energy consumption, air emissions, and solid waste
generation. Because Option 2 is similar to Option 1, but would result in fewer operational
changes at a subset of airports and therefore lead to fewer non-water quality impacts than Option
1, EPA did not analyze non-water quality impacts associated with Option 2. Rather, EPA
concluded that the results for Option 2 will be similar to or less than Option 1. Additionally,
Option 3 has no associated non-water quality impacts as substituting one airfield deicing product
with another causes no increase in energy usage, air emissions, or solid waste generation.
12.1 Energy Requirements
EPA estimated that the total incremental electrical usage for Option 1 to pump ADF-
contaminated stormwater into storage tanks would be approximately 1.2 million kilowatt hours
per year (kWh/yr). EPA also developed a relationship between electrical use and COD removal
by the AFB bioreactors based on information provided by Albany International (ALB) airport.
Using ALB's information, EPA estimated the electrical requirement for COD removal for
Option 1 as approximately 1.3 kWh/lb COD removed. Using this unit rate, EPA estimated total
electrical requirements to remove COD for Option 1 to be a maximum additional 22 million
kWh/yr.
EPA also analyzed fuel use by GCVs collecting ADF-contaminated stormwater. EPA
used airport questionnaire data for diesel fuel costs for GCVs and then estimated an average
diesel fuel use based on the unit cost for diesel fuel of $2.07/gal.6 EPA then estimated annual
fuel usage per gallon of applied ADF to be 0.08 gal/gal ADF applied. Using this relationship,
EPA estimated that the total incremental consumption of No. 2 diesel fuel, at all airports subject
to BAT and installing additional collection equipment, is 354,500 gallons per year.
Additionally, as EPA assumes that aircraft operations will not be delayed as a result of
Option 1 and that deicing will occur at the gates, there is no increase in jet fuel consumption
associated with Option 1.
Below are the calculations to determine the net energy requirements associated with
Option 1 of the final rule for the collection and treatment of ADF-contaminated stormwater.
Detailed calculations regarding net energy consumption for the various collection and treatment
technologies considered for the rule are provided in a separate memorandum entitled Energy
Requirements for ADF Contaminated Stormwater Collection and Treatment Alternatives (ERG,
2008a).
6 This diesel fuel price was the average reported by the Energy Information Administration (EIA) for the 2004-05
winter season, the same period that EPA is analyzing for airport deicing activity.
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To estimate incremental electrical requirements associated with pumping collected ADF
to storage tanks, EPA assumed airports would continuously operate three well-pit pumps with
40-horsepower (hp) electric motors during each deicing day. EPA also conservatively assumed
that all airports would use pumps rather than allow ADF-impacted stormwater to flow by gravity
to holding tanks. To estimate electrical use by airport based on the number of deicing days per
year, EPA developed the following equation:
Pumping Electrical = 3 pumps x 40 ^ x 0.7456 x 24 x SOFP (12-1)
pump hp day yr
Using the equation above, the total SOFP days for those airports that EPA assumed
would install additional collection equipment, and a wire-to-water efficiency of approximately
40 percent (Bower, H., 1978), the total incremental electrical usage to pump ADF-contaminated
stormwater into storage tanks would be approximately 1.2 million kilowatt hours per year
(kWh/yr).
EPA developed another relationship between electrical use and COD removal by the
AFB bioreactors based on information provided by Albany International (ALB) airport. Using
ALB's information, EPA estimated the electrical requirement for COD removal as
approximately 1.3 kWh/lb COD removed. Using this unit rate, EPA estimated the total electrical
requirements associated with COD treatment. EPA estimates an additional 22 million kWh/yr
will be required to remove 16,602,900 total pounds per year of COD as a result of the final rule.
The national estimated increase in electrical power consumption related to increased
pumping and AFB treatment is 23.2 million kilowatt hours per year. This represents a very small
fraction (0.0006 percent), of the electrical energy used annually in the United States, which is
3,950 billion kWh based on EIA statistics.
EPA notes that AFB treatment systems also generate biogas that can be used as a source
of heat when burned in facility boilers or when converted to electricity using technologies such
as microturbines or fuel cells. EPA did not include microturbine costs in its option-costing
methodology. However, to estimate the potential electricity that could be generated if all AFB
treatment systems installed microturbines to generate electricity, EPA developed a relationship
between biogas generation and COD removal based on data provided by ALB airport. EPA
estimated the AFB reactors will generate approximately 8 cubic feet of biogas per pound of COD
removed, and the biogas is approximately 60 percent methane. Because one cubic foot of
methane provides 100 therms and 1 therm is equivalent to 29.3 kWh when converted to electrical
energy (U.S. Code, Title 15), EPA was able to predict the potential electrical energy available
from biogas generated by the AFBs treating ADF-contaminated stormwater (see Table 12-1).
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Table 12-1. Potential Electricity Generation from AFB Biogas Generation
Regulatory
Scenario
Total COD
Removal
(pounds/vr)
Potential Biogas
Generation
(million t't3/yr)1
Potential Methane
Generation
(million ftJ/yr)2
Potential Electrical
Generation
(million kWh/vr)J
40% ADF Capture
16,602,900
129
77.5
23
Calculation based on 8 cubic feet of biogas per lb COD removed.
2Assumes biogas is approximately 60% methane per Metcalf and Eddy Wastewater Engineering and Design
(Metcalf and Eddy, 1979).
Calculation based on 100 therms per cubic foot of methane and 29.3 kWh per therm.
Comparing the potential electrical generation from converting biogas to electricity to the
electrical requirements discussed above indicates that AFB treatment of ADF-contaminated
stormwater could generate most of the electricity needed to operate the treatment systems.
Fuel use by GCVs collecting ADF-contaminated stormwater is another incremental
energy requirement for compliance with Optionl. To estimate incremental diesel fuel use by
GCVs, EPA obtained annual diesel fuel costs for GCVs from the airport questionnaire (U.S.
EPA, 2006) and then estimated diesel fuel use based on the unit cost for diesel fuel (e.g., $/gal).
According to questionnaire data, one airport spent $17,600 on diesel fuel to operate GCVs to
recover ADF-contaminated stormwater during the 2004-2005 deicing season, collecting
approximately 20 percent of their applied ADF in stormwater. Based on an average diesel fuel
cost of $2.07 per gallon during the 2004/2005 deicing season (U.S. DOE, 2006), EPA estimates
this airport burned approximately 8,500 gallons of diesel fuel in GCVs. Based on annual ADF
use and size, EPA estimated diesel fuel use in GCVs to be 0.08 gal/gal ADF applied. Using this
relationship, EPA estimated total incremental No. 2 diesel fuel consumption at in-scope airports
installing additional collection equipment to be 354,500 gallons per year. This volume is a
conservative estimate because it is based on an airport that currently uses only GCVs to collect
ADF-contaminated stormwater (e.g., 20 percent ADF collection). If airports install a plug and
pump system to collect ADF-contaminated stormwater, GCV usage and therefore diesel fuel use
are expected to be less.
EPA compared incremental diesel fuel use by GCVs at all airports to diesel fuel use on a
national basis. According to the EIA, approximately 25.4 million gallons per day of No. 2 diesel
fuel was consumed in the United States in 2005 (U.S. DOE, 2006). Total annual diesel fuel use
by GCVs to collect ADF-contaminated stormwater at airports would account for a small fraction,
0.004 percent, of the annual diesel fuel use on a national level.
12.2 Air Emissions
Additional air emissions as a result of the final rule can be attributed to added diesel fuel
combustion by GCVs collecting ADF-contaminated stormwater and from anaerobic treatment of
ADF. Emissions from these sources are discussed below.
12.2.1 Emissions from GCV Collection
As discussed in Section 12.1, EPA conservatively estimated that GCVs collecting ADF-
contaminated stormwater at airports will consume an additional 354,500 gallons per year of No.
2 diesel fuel. To estimate air emissions related to combustion of No. 2 diesel fuel in GCVs'
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internal combustion engines, EPA used published emission factors for internal combustion
engines (U.S. EPA, 1996 AP-42). The Agency selected emission factors for gasoline and diesel
industrial engines rather than on-road mobile sources because the emission factors for the
industrial engines include equipment such as forklifts and industrial sweepers and scrubbers
(U.S. EPA, 1006 AP-42). To estimate emissions from the GCVs, EPA first converted the
additional 354,500 gallons of diesel fuel to million British Thermal Units (MMBtu) and then
applied the appropriate emission factors (U.S. EPA, 1996 AP-42). Table 12-2 shows the
estimated increase in criteria pollutant emissions associated with the use of GCVs. Additional
details regarding emissions from GCVs are contained in a memorandum titled Air Emissions
from Airport Deicing Collection and Treatment Technologies (ERG, 2008b).
Table 12-2. Estimated Incremental Pollutant Emissions from GCVs
( rilerhi P0II111 ;i 111
Diesel l-uel
Consumption in
((A Inleniiil
(omhiislion r.niiinc
(ii;il/\ r)
Diesel l-'uel
( oiisii 111 pi ion in (;( V
liilei'ii;il ( omhiislion
Inline
(MMIiliiAr) 1
I'lmission l-'iielor lor
Diesel l-'uel
( omhiislion in
Inleriiiil ( omhiislion
lln^ine I Ihs/M M ISln r
llsliniiiled Anniiiil
Emissions I'm 111
(>( Ys IS11 rnin;i Diesel
l-nel
(lonsA 1)
Carbon Monoxide
354,500
49,630
0.95
24
Carbon Dioxide
354,500
49,630
164
4,070
Nitrogen Oxides
354,500
49,630
4.41
109
Sulfur Dioxide
354,500
49,630
0.29
7
PM10
354,500
49,630
0.31
8
Heat content of diesel fuel is approximately 140,000 Btu/gal per Perry's Chemical Engineers Handbook, 6th
Edition, Figure 9-4.
2Emission factors from EPA Compilation of Emission Factors AP-42.
PMio - Particulate matter less than 10 um.
The annual emissions provided in Table 12-2 indicate that an additional 4,070 tons per
year of carbon dioxide would be emitted from GCVs combusting additional diesel fuel to comply
with the regulatory options evaluated in the final rule. Carbon dioxide is the primary greenhouse
gas attributed to climate change; although 4,070 additional tons per year appears to be
considerable, the amount is very small relative to other sources. For example, in 2006, industrial
facilities combusting fossil fuels emitted 948 million tons of CO2 equivalents. An additional
4,070 tons per year from GCVs is an increase of 0.0004 percent in the overall C02 emissions
from all industrial sources (U.S. EPA, 2008).
Comments provided by industry on the proposed rule correctly indicated that additional
nitrogen oxides would be emitted by equipment constructing the ADF-contaminated stormwater
collection systems, the AFB treatment system, and any ancillary systems such as roadways and
storage tanks. According to comments, the Environmental Assessment for the Portland ADF
collection and treatment system estimated annual nitrogen oxide emissions at 4.48 tons/yr during
construction. Construction of the ADF collection and treatment system in Portland was estimated
to occur over approximately 2.5 years, resulting in total nitrogen oxide emissions of 11.2 tons.
Based on the number of in-scope airports that would potentially require construction under
EPA's Option 1, total construction-related nitrogen oxide emissions will be approximately 168
tons. In comparison, EPA estimated total nitrogen oxide emissions in the United States at 18.3
million tons (U.S. EPA, 2005).
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12.2.2 Emissions from AFB Treatment Systems
Anaerobic digestion of glycols found in ADF-contaminated stormwater generates biogas
containing approximately 60 percent methane and 40 percent carbon dioxide. Airports installing
AFBs to treat ADF-contaminated stormwater are expected to burn a portion of the gas in on-site
boilers to maintain reactor temperature. The remainder of gas can be either combusted in a
microturbine for electricity generation or flared. Regardless of the combustion technology,
nearly all biogas generated by AFBs is converted to carbon dioxide, the primary green house
gas.Table 12-3 shows biogas generation and potential carbon dioxide emissions from AFB
treatment systems for the costed collection scenario.
Table 12-3. Potential Air Emissions from AFB Treatment Systems
Regulatory Scenario
Total COD Removal
(pounds/vr)
Potential Biogas
Generation
(million ttJ/vr)1
Potential Carbon Dioxide
Generation
(tons/yr)2
40% ADF Capture
16,602,900
129
3,730
Calculation based on 8 cubic feet of biogas per lb COD removed. Biogas is 60% methane and 40% C02.
2 Assumes 99.9 percent of biogas is converted to C02 during combustion.
Carbon dioxide is the primary greenhouse gas attributed to climate change; although
3,730 additional tons per year for 40 percent ADF capture appears to be considerable, the
amount is very small relative to other sources as discussed in 12.2.1.
12.3 Solid Waste Generation
AFB bioreactors will generate sludge that will require disposal, likely in an off-site
landfill. To estimate the potential for annual sludge generation by AFB bioreactors treating ADF-
contaminated stormwater under Option 1, EPA first estimated the potential COD removal for the
collection and treatment scenario and then applied published anaerobic biomass yield
information (Metcalf & Eddy, 1979) to estimate potential total sludge generation on a national
basis. The biomass yield calculation, which simply multiplies the COD removal by the yield, is a
rough method of estimating sludge generation and does not account for other factors such as
degradation or inorganic material (e.g., AFB media) that may be entrained into the sludge.
However, this method does provide an order of magnitude estimate of sludge generation that can
be compared to other types of common biological treatment systems to determine if AFB sludge
generation would be unusually high at airports treating ADF-contaminated stormwater.
Table 12-4 shows the total COD removal for the collection and treatment scenario and
the estimated sludge that would likely require disposal. This sludge is expected to be
nonhazardous and can be disposed of in a municipal landfill. Detailed calculations showing how
EPA estimated biomass amounts are provided in a memorandum entitled Estimated Sludge
Generation from AFBs Treating ADF-Contaminated Stormwater (ERG, 2008c).
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Table 12-4. Estimated Sludge Generation from AFB Bioreactors Treating ADF-
Contaminated Stormwater
Regulatory Scenario
Total COD Removal
(pounds/yr)1
Anaerobic Biomass Yield
(lbs biomass/lb COD
removed)2
Total Sludge Generation
(dry tons/yr)
40% ADF Capture
16,602,900
0.03
271
Total COD removal from all AFB bioreactors that may be installed at airports.
2Biomass yield from Metcalf and Eddy.
To provide some perspective on the potential total amount of biomass produced annually
by the AFB biological reactors treating ADF-contaminated stormwater, EPA compared the total
biomass generation data in Table 12-4 to the national biosolids estimates for all domestic
wastewater treatment plants throughout the United States. According to EPA's Municipal and
Solid Waste Division, approximately 8.2 million dry tons of biosolids will be produced in 2010
(U.S. EPA, 1999). Using the biosolids generation amount shown in Table 12-4 (271 tons/yr),
EPA estimates that AFB bioreactors treating ADF-contaminated stormwater would increase
biosolids generation in the United States by approximately 0.003 percent.
12.4 Summary
EPA reviewed the potential non-water quality impacts of collection and treatment of
spent ADF using plug and pump with GCVs combined with an AFB treatment system and
determined that there was an insignificant increase in energy usage and generation of air
emissions and solid waste.
EPA then determined that the other regulatory options under consideration would have
similarly insignificant impacts because the other regulatory options involve fewer or no GCVs
and smaller or no treatment system. Based on this evaluation of non-water quality impacts, EPA
concludes there are no non-water quality impacts associated with today's final rule.
12.5 References
Bouwer, H. 1978. Groundwater Hydrology. McGrawHill Press.
ERG. 2008a. Memorandum from Mark Briggs (ERG) to Airport Deicing Administrative Record.
Energy Requirements for ADF-Contaminated Stormwater Collection and Treatment
Alternatives. (December) DCN ADO 1166
ERG. 2008b. Memorandum from Mark Briggs (ERG) to Airport Deicing Administrative Record.
Air Emissions from Airport Deicing Collectoin and Treatment Technologies. (December) DCN
AD01165
ERG. 2008c. Memorandum from Mark Briggs (ERG) to Airport Deicing Administrative Record.
Estimated Sludge Generation fromAFBs Treating ADF-Contaminated Stormwater. (December)
DCN ADO 1164
Metcalf and Eddy. 1979. Wastewater Engineering, Treatment/Disposal/Reuse, Second Edition.
McGraw Hill Press.
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U.S. Code Title 15, Commerce and Trade, Chapter 6. 2007. Weights and Measures and Standard
Time. (January).
U.S. DOE. 2006. Department of Energy, Energy Information Administration (EIA), No. 2 Fuel
Oil All Sales/Deliveries by Prime Supplier. DCN AD00919.
USEPA. 1996. Compilation of Air Pollutant Emission Factors (AP-42), Fifth Edition, Section
3.3. U.S. Environmental Protection Agency. Washington, D. C.
USEPA. 1999. Biosolids Generation, Use and Disposal in the United States. U.S. Environmental
Protection Agency. Washington, D. C. EPA 530D-R-99-009.
USEPA. 2005. Summary of Nitrogen Oxides Emissions. U.S. Environmental Protection Agency.
Available online at http://www.epa.gOv/air/emissions/nox.htm#noxnat.
USEPA. 2006. Airport Deicing Questionnaire. U.S. Environmental Protection Agency.
Washington, D.C. DCN AD00354.
USEPA. 2008. Inventory of U.S. Greenhouse gas Emissions and Sinks: 1990 - 2006. U.S.
Environmental Protection Agency. Washington, D. C. (April). EPA 430-R-08-05.
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Section 13 - Limitations and Standards: Data Selection and Calculation
13. Limitations and Standards: Data Selection and Calculation
This section describes the data selection and statistical methodology that EPA used to
calculate the final rule limitations for the Airport Deicing Category. As described in this section,
the effluent limitations and standards account for variation in treatment performance of the
model technology. For simplicity, the following discussion refers only to effluent limitation
guidelines; however, the discussion also applies to new source standards.
EPA is finalizing limitations for COD and ammonia as nitrogen (the latter as a
compliance alternative), and Section 13.1 briefly describes the pollutant parameters. Section 13.2
provides an overview of EPA's data review and selection process. Section 13.3 describes EPA's
data conventions. Sections 13.4 and 13.5 describe the COD and ammonia as nitrogen data
selected as the basis of the final limitations. Section 13.6 describes the percentile basis and
calculations used for the limitations. Section 13.7 describes achievability and compliance related
to the limitations.
13.1 Selected Pollutant Parameters
As described in Section 6, there are a number of pollutants associated with discharges
from airport deicing operations. EPA is setting effluent limitations for two pollutant parameters,
COD and ammonia. This section briefly describes the pollutant parameters and the chemical
analytical methods used to measure their concentrations.
13.1.1 COD
COD is a measure of the total organic matter content of both wastewaters and natural
waters. Measurement of COD can be used to rapidly recognize deterioration in wastewater
treatment plant performance and the need for corrective action. EPA evaluated data collected by
the Albany International Airport in New York and by EPA. The Agency evaluated data for COD
that was measured using EPA Method 410.4 and Hach 8000, both of which are approved for
compliance monitoring in 40 CFR Part 136. EPA measured COD using Method 410.4, and
Albany Airport used Hach 8000. Data from the two methods are directly comparable.
Method 410.4 is a colorimetric procedure with a measurement range of 3 to 900 mg/L for
automated procedures and a measurement range of 20 to 900 mg/L for manual procedures. The
Hach 8000 method is a colorimetric procedure that utilizes a preliminary digestion procedure and
can be used for various concentration ranges. A user has the option of purchasing three different
sets of reagents and standards. The first has a measurement range of 0 to 40 mg/L; the second, 0
to 150 mg/L; and the third, 0 to 1500 mg/L. The industry data had a lower measurement limit of
2.0 mg/L.
13.1.2 Ammonia as Nitrogen (Ammonia)
Ammonia as nitrogen (ammonia) is generated as a by-product of using urea-containing
products for deicing operations. Ammonia can be directly toxic to fish and other aquatic
organisms and can reduce ambient dissolved oxygen concentrations in receiving surface waters.
In the data EPA evaluated, ammonia was measured using Methods 350.1 and 350.2, both of
which are approved for compliance monitoring in 40 CFR Part 136. Albany Airport supplied
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data that was generated using Method 350.1 (ERG, 2008), and EPA used Method 350.2. Both
methods produce comparable results.
Method 350.1 is an automated colorimetric method that uses a continuous flow analytical
system and has a detection range of 0.01 to 2.0 mg/L. Method 350.2 utilizes either colorimetric,
titrimetric, or electrode procedures to measure ammonia. Method 350.2 has a lower measurement
range limit of 0.20 milligrams per liter (mg/L) for the colorimetric and electrode procedures and
a lower measurement range limit of 1.0 mg/L for the titrimetric procedure.
13.2 Overview of Data Review and Selection
As described in Sections 13.4 and 13.5, EPA qualitatively reviewed all the available
influent and effluent data for COD and ammonia. For purposes of limitation development, data
are defined to be numerical values resulting from laboratory determination of pollutants in
physical samples collected from influent and effluent wastestreams. A laboratory expresses the
results of its analysis either numerically or as "not quantitated" for a pollutant in a sample. When
the result is expressed numerically, the pollutant was quantitated, or more commonly referred to
as "detected," in the sample. The definition includes measured values (e.g., 10 mg/L) and values
reported as being below some level of quantification (e.g., <10mg/L). The latter are often
referred to as "nondetected" and are usually reported with a "detection limit." (EPA also uses
terms such as "quantitation limit" in other documentation.) The definition of "data" excludes
estimated values and statistical summaries, such as averaged values.
This section describes EPA's review of the available data. Section 13.2.1 describes the
criteria that EPA applied in selecting data for the development of the final limitations. Section
13.2.2 describes other considerations that were evaluated as part of the data review.
13.2.1 Data Selection Criteria
This section describes the criteria that EPA applied in selecting data to use as the basis
for the final effluent limitations. EPA has used these or similar criteria in developing limitations
and standards for other industries. EPA uses these criteria to select data that reflect consistently
good performance of the model technology in treating the industrial wastes under normal
operating conditions. Model technology is technology that is carefully designed and diligently
operated. The following paragraphs describe the criteria and modifications specific to the Airport
Deicing Category.
One criterion generally requires that the influent and effluent from the treatment
components represent typical wastewater from the industry, with no incompatible wastewater
from other sources (e.g., sanitary wastes). By applying this criterion, EPA selects only those
facilities where the commingled wastewaters did not result in substantial dilution, unequalized
slug loads that result in frequent upsets and/or overloads, more concentrated wastewaters, or
wastewaters with different types of pollutants than those generated by the categorical (i.e.,
airport deicing) wastewater.
A second criterion typically ensures that the pollutants were present in the influent at
sufficient concentrations to evaluate treatment effectiveness. To evaluate whether the data meet
this criterion for the final rule, EPA often uses a "long-term average test" for sites where it has
paired influent and effluent data. EPA has used such comparisons in developing regulations for
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other industries (e.g., the Iron and Steel Category (USEPA, 2002)). The test looks at the influent
concentrations to ensure a pollutant is present at sufficient concentration to evaluate treatment
effectiveness. If a pollutant fails the test (i.e., is not present at a treatable concentration), EPA
excludes the data for that pollutant at that facility from its long-term average and variability
calculations. In this manner, EPA would ensure that the limitations resulted from treatment and
not simply the absence or substantial dilution of that pollutant in the wastestream. If industry
supplies EPA with effluent data, but not the corresponding influent data, EPA may choose to use
the effluent data without performing a long-term average test provided it determines that the
pollutant would have been present at consistently treatable concentrations at the facility. This
approach would satisfy EPA's objective to include as much data from as many facilities as
possible in the calculation of limits.
A third criterion requires that the facility must have the model treatment technology and
demonstrate consistently diligent operation. The Agency may include facilities with treatment or
performance that is equivalent to the model technology, but this is rare. EPA generally
determines whether a facility meets this criterion based upon site visits, ability to comply with its
existing discharge requirements, discussions with facility management, and/or comparison to
treatment system performance at other facilities. EPA often contacts facilities to determine
whether data submitted were representative of normal operating conditions for the facility and
equipment. Based on this review, EPA typically eliminates facilities that experience repeated
operating problems with their treatment systems. In addition, EPA typically excludes data when
the facility has not optimized its treatment. For example, facilities may use the model technology
as a pretreatment step before sending the wastewater to a POTW and consequently might not
fully optimize its system.
A fourth criterion typically requires that the data cannot represent periods of frequent
unequalized slug loading treatment upsets or shut-down periods7 because these excursion data do
not reflect performance that would be expected from well-designed and operated treatment
systems. Furthermore, it would not be appropriate for the limitations to be based, in part, upon
data reflecting extreme events that are beyond the control of the facility, because regulatory
provisions at 40 CFR 122.41(n) would apply to such circumstances. More specifically, after the
final limitations are incorporated into permits, EPA expects that, when such events occur, the
facility would abide by the procedural requirements in ง122.41(n) to obtain an affirmative
defense to any potential enforcement action.
In applying the fourth criterion, EPA evaluates the pollutant concentrations, flow values,
mass loadings, plant logs, and other available information. As part of this evaluation, EPA
typically asks the facility about process or treatment conditions that may have caused extreme
values (high and low). EPA may consequently identify certain time periods and other outliers in
the data that reflect poor performance by an otherwise well-operated site.
7 EPA applies this criterion to data from two types of shut-downs. First, treatment systems are sometimes halted to
control upset conditions. As part of the recovery activities, the facility may pump out wastewater from the
equipment (e.g., tanks) which contains highly concentrated wastes associated with the upset. Second, the facility
may shut down its operations for maintenance and other atypical operations. During these periods, the facility may
still operate its treatment system, but typically discharges effluent associated with atypical influent. For example, the
influent might include cleaning solvents instead of process wastewater.
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EPA also applies the fourth criterion in its review of data corresponding to "start-up"
periods, an adjustment period that most industries incur only when installing, acclimating, and
optimizing new treatment systems. During this adjustment period, the concentration values tend
to be highly variable with occasional extreme values (high and low). After this period, the
systems should operate at steady state for years with relatively low variability around a long-term
average. Because start-up conditions typically reflect one-time operating conditions, EPA
generally excludes such data in developing the limitations. In contrast, EPA expects airports to
encounter start-up operations at the start of every deicing season because they probably will
cease treatment operations during warmer months. Because this adjustment period will occur
every year for the Airport Deicing Category, EPA is including start-up data in the data set used
as the basis of the limitations. However, through its application of the other three criteria, EPA
would exclude extreme conditions that do not demonstrate the level of control possible with
proper operation and control even during start-up periods.
In part, by retaining start-up data for limitations development, the limitations will be
achievable because EPA based these limits on typical treatment during the entire season. Once
the treatment system reaches steady state, EPA expects a typically well-designed and operated
system to run continuously until the end of the deicing season.
13.2.2 Other Considerations in Data Selection
In comments on proposed regulations across a range of industry categories and
subcategories, industries often suggest that EPA consider additional criteria in selecting data as
the basis of the limitations. EPA routinely evaluates whether the suggested criteria are relevant
and should be considered as it develops new regulations. As explained below, EPA also
considered additionalcriteria for the airport deicing rulemaking, but determined that they were
not relevant in selecting data as the basis of the final limitations. EPA's rationale is consistent
with its findings for other industries.
Commenters often suggest a criterion related to the size of facilities because of concerns
about a perceived impact of volume, or flow, of wastewater on treatment performance. In
considering this issue for the airport deicing industry, EPA concluded that the size of the airport,
collection technology, and other features by themselves would not affect the performance of the
treatment system. Instead, the airport size and water flow would determine the size of the
treatment system, rather than its performance. EPA expects that each airport would build and
operate a system that is sized appropriately for its volume of wastewater. Because the method of
treatment is the same regardless of the flow, properly sized systems should all perform in the
same manner, and achieve the same effluent concentrations. Before reaching this conclusion for
airport deicing and other industries, EPA reviewed treatment technologies such as biological
treatment, oil-water separators, dissolved air floatation, and settling tanks. EPA's record supports
the finding that, for a variety of industrial sectors, well-operated and designed treatment systems
treat different wastewaters with varying flows to a narrow range of effluent concentrations
(USEPA, 2010).
In addition, commenters typically suggest a criterion that would require a minimum
number of facilities be used as the basis of the limitations. Such suggestions are based upon two
main concerns. First, commenters are concerned that the limitations do not reflect treatment from
a range of typical influents, because the concentration levels vary from facility to facility.
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Second, commenters are concerned that not all facilities could achieve the same high level of
performance using the model technology. For the first concern, as part of its evaluation of the
effect of flow described above, EPA also considered the impact of influent pollutant
concentrations. EPA found that well-operated and designed treatment systems are capable of
treating the wastewaters to a narrow range of effluent pollutant concentrations. For the second
concern, EPA only needs to demonstrate that the model technology can be operated at the level
of performance on which the limitations are based. EPA's selection of the model technology
used at the Albany International airport as the basis of the limitations is appropriate because that
facility demonstrates that the technology can achieve the levels reflected in the final limitations.
The CWA authorizes EPA to base BAT/NSPS limitations and standards on
the performance of a single facility and it is not unusual for EPA to base effluent
limitations on data from a single facility. For example, in the Organic Chemicals, Plastics and
Synthetic Fibers (OCPSF) effluent guideline promulgated in 1987, EPA based 38 percent of the
limitations on the performance of a single facility (USEPA, 1987). Courts have recognized that
EPA must act on the information it has and need not wait for perfect information(e.g., see BASF
Wyandotte Corp. v. Costle, 598 F.2d 637, 652-653 (1st Circuit, 1979)).
13.3 Conventions for Modeling Multiple Data Sets from the Same Facility
This section describes EPA's conventions for modeling multiple data sets from the same
facility. Data from a particular facility are sometimes collected at different times, from different
treatment units, or by different organizations. In such cases where multiple data sets exist for the
same facility, EPA often statistically models the data as if each data set represents a different
facility. This section describes conventions applied to the data from the airport deicing industry.
EPA generally considers data from different time periods to characterize different
operating conditions due to changes such as management, personnel, and procedures. Because
EPA expects airports to operate treatment systems only for a limited time each year, it
considered whether the conditions and performance for each deicing season tend to vary in a
manner that more appropriately reflects different treatment systems. Because it may better
capture the variability of airport deicing operations under a range of conditions, EPA has
calculated the final limitations using all of the data, without regard to season. For informational
purposes, the data and summaries are presented by season.
EPA generally uses data from separate treatment units (depending on the rulemaking,
also called "trains" or "systems") as if they characterized separate facilities. EPA has determined
this is appropriate because the units were operated separately. Even if the wastes were generated
by the same processes or drawn from the same storage pond, EPA considers that the performance
of each system can vary due to slightly different influents, equipment, and other factors.
EPA generally considers data from different organizations to characterize different
collection methods and analytical methods. The different organizations typically are EPA
sampling teams and the facility's monitoring crew at the treatment system. EPA often separates
such data into multiple data sets, to better model the variability consistent with the use of a single
analytical method and the same collection procedures. Consistent use of a single method and
procedure is often required by permits and is typical of compliance monitoring. Therefore, the
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Agency generally uses this convention to model typical variability that each facility would
experience in compliance monitoring activities. EPA then determines which, or all, multiple data
sources are appropriate choices as the basis of the limitations.
13.4 COD: Data Selected as Basis of Final Limitations
In establishing the final limitations, EPA reviewed COD data from a treatment plant at
the Albany International airport, which used the model BAT. (Selection of the model technology
is described in Section 8 and in the preamble to today's rule.) EPA collected COD data during a
sampling episode at Albany International airport and obtained several years of monitoring data
and other information from the airport. After evaluating these data, EPA determined that the
Albany data were the only available performance data from the model technology.8 Thus, all
other data sets were excluded by applying the third criterion in Section 13.2.1, because they did
not demonstrate the performance of the model technology. The following sections describe the
Albany airport and apply the criteria in identifying the specific data points used as the basis of
the final limitations.
13.4.1 Albany Treatment System
EPA based the final limitations for COD upon data from Albany Airport's treatment
system. This system consists of two identical units that are consistent with EPA's model
technology described in Section 8. The airport diverts stormwater from deicing operations into a
lagoon. Facility personnel then pump water from the lagoon to one anaerobic unit or the other for
treatment. The airport generally operates the two treatment systems in parallel, but sometimes
runs them in series. At the end of each unit, regardless of whether the system is in parallel or
series, the airport monitors COD concentrations each morning by collecting grab samples to
evaluate the treatment performance. These locations are labeled as ArprtR-101 and ArprtR-102
in Figure 13-1. During its five-day sampling episode conducted from February 5-9, 2006, EPA
measured COD and ammonia concentrations in composite samples collected at a point (labeled
EPA SP-2) where the two units combine into a single flow before entering an aerobic polishing
pond for more treatment. After this step, the airport typically directly discharges waste into
Shaker Creek, a tributary of the Mohawk River, which has been classified as a New York State
Class A drinking water stream. As a consequence, the airport is required to meet stringent
limitations when it discharges directly to the creek. In warmer weather (i.e., when the soil is 50
degrees or warmer), the airport sometimes uses the treated wastewater for irrigation. In addition,
the airport is able to discharge to a POTW, although it seldom does.
8 Akron Canton Airport in Ohio started operating the model technology in mid-November in 2007. When EPA was
completing its technical analysis of the industry in late spring 2008, the airport's treatment unit was not operating at
full capacity.
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Aerobic
polish
Lagoon
(COD. \miiknii;i)
Anaerobic unit #2
Anaerobic unit # 1
Figure 13-1. Simplified Drawing of Albany Airport Treatment System and Sample Points
As the basis for the final limitations for COD, EPA selected the data at sample points
ArprtR-101 and ArprtR-102 because each unit is the same as the model treatment system that
EPA identified in Section 11. The airport has monitored its performance for a relatively long
time and provided EPA with data from December 1, 1999, through April 10, 2009 (10 deicing
seasons). Because the influent was highly concentrated, it was not necessary to perform the long-
term average test described in Section 13.2.9
DCN AD01181 provides the influent and effluent COD data as originally submitted by
the airport and the data are graphically displayed in the statistical support memorandum
(USEPA, 2006). The following sections describe the exclusion of data collected from the EPA
sampling episode and the airport's self-monitoring data.
13.4.2 COD Data from EPA Sampling Episode at A Ibany
During EPA's sampling episode, EPA and the airport collected separate sets of samples
(see Table 13-1 analytical results). At sample point EPASP-2, EPA collected samples of the
combined flow from the two units. In contrast, the airport monitored the effluent directly from
each unit at sample points ArptR-101 and ArptR-102 and filtered the samples prior to analyzing
for COD. Both sets of samples demonstrate the performance of the model technology because no
additional treatment steps exist between the airport sample points and EPA's sample point.
Rather than include data from two different sources (i.e., EPA and the airport) for the same dates,
EPA preferentially selected the airport data because they were part of longer-term monitoring.
Although the EPA data were therefore excluded as the basis of the limitations, EPA notes that all
of the values are less than the value of 271 mg/L for the final daily maximum limitation.
9 EPA typically compares average influent levels to a multiplier of 5 to 10 times the quantitation limit (or reporting
limit). As explained in Section 13.1.1, the airport data had a lower measurement limit of 2.0 mg/L. Thus, in the long-
term average test, EPA would probably have compared the influent data to a reference level of 10 to 20 mg/L.
However, because the minimum influent value of 100 mg/L exceeded this range of potential reference values, the
average values also will meet the requirements of the long term average test.
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Table 13-1. COD: EPA and Albany Airport Self-Monitoring Effluent Data Collected
During EPA's Sampling Episode
Sample Date
COD Concentrations (mg/L)
EPA Sampling Episode Data
Airport Self-Monitoring Data
Original Sample
Field Duplicate
(where collected)
AprtR-101
AprtR-102
2/5/06
72
29
74
2/6/06
228
208
53
108
2/7/06
92
177
56
94
2/8/06
81
31
90
2/9/06
193
48
96
13.4.3 COD Self-Monitoring Data from Albany Airport
The airport typically runs the two units in parallel. EPA considers each unit's
performance, when operated in this manner, to be consistent with the model technology. In its
evaluation of the data from each unit, EPA applied the criteria and other considerations described
in Section 13.2. As a result of this evaluation, EPA excluded data associated with atypical
operations, influent concentrations reported as zero, estimated values, and poor performance.
The exclusions are described below.
By applying the third criterion in Section 13.2.1, EPA excluded all periods when the units
were operated in series because the data did not reflect treatment by the model technology. Table
13-2 identifies these time periods by deicing season (e.g., Season99 started in 1999 and
continued into 2000). During these periods, one unit provided initial treatment and the second
provided additional treatment. Although the facility reported effluent values from each unit
during this period of operating in series, it only discharged the effluent from the second unit in
the series. EPA considers the effluent data from the first unit to reflect less than optimal
performance, because the operators presumably would have not optimized treatment as they
intended to treat the wastes a second time (criterion 3). EPA considers the effluent data from the
second unit to characterize treatment of atypical influent (i.e., effluent that had been treated by
the first unit).
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Table 13-2. COD: Dates Excluded Because Units Operated in Series
Season
Number Days Eveluded
Beginning Date
End Date
Season99
32
2/9/2000
3/11/2000
SeasonOO
31
12/12/2000
1/11/2001
SeasonOl
3
2/7/2002
2/9/2002
Season02
8
11/17/2002
11/24/2002
3
4/5/2003
4/7/2003
Season05
25
1/10/2006
2/3/2006
Season06
79
1/15/2007
4/3/2007
Season07
31
2/2/2008
3/3/2008
Season08
25
11/17/2008
12/11/2008
EPA excluded effluent values for both units when the influent concentration was reported
as "zero" for two reasons. First, if COD could not be detected in the influent (criterion 2), then
the effluent concentrations would not reflect any additional treatment. Second, it appears that the
plant used this convention to indicate shut-downs of the system (criterion 4). Table 13-3
identifies the dates when the influent concentration was reported to be zero.
Table 13-3. COD: Dates Excluded Because Influent Concentration Reported as Zero
Season
Date
SeasonOl
6/14/2002
Season02
11/16/2002
Season06
4/10/2007
EPA also excluded any values that were estimates because they did not meet EPA's
definition for "data" described in Section 13.2. There were two types of estimated values. One
type was in italics in the facility's spreadsheets, indicating that the operator's log noted issues
with the sample or its analysis, and thus, the reported value was an estimate. The second type
was a series of identical values reported over consecutive monitoring days. Although it is
possible to find exactly the same pollutant concentrations on consecutive days, variations from
day to day are more typical. In response to EPA's questions about the strings of identical values,
the facility stated that it sometimes repeated the last known number when they did not monitor
(ERG. 2008a). To model the variability likely to be present in the effluent, EPA assumed that the
first non-zero value was the only day when COD was monitored when three or more days had
identical values for the same unit. Therefore, EPA retained the value for the first day and deleted
the (identical) values on subsequent days for that unit. If the values were zero, EPA assumed that
the unit was not operating and excluded the entire time period, including the first reported zero
value. The statistical support memorandum (USEPA, 2010) identifies these exclusions.
In addition, by applying the fourth criterion in Section 13.2, EPA excluded periods that
did not reflect the typical performance of the technology. As shown in Table 13-4, these
exclusions included treatment system upsets and method error. For example, EPA excluded the
maximum value of 1,283 mg/L recorded at ArprtR-101 on 3/21/2001 because it was inconsistent
with the other data values during that time period. The plant management agrees that the value
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does not reflect normal operations and suspects that it was likely a sample with high solids
content (ERG. 2008b).
Table 13-4. COD: Dates Excluded Because of Performance Excursions
Season
Number Days Exeluded
Beginning Date
End Date
Reason
Season99
11
12/1/2000
12/11/2000
System Upset
SeasonOO
42
1/12/2001
2/22/2001
System Upset
1
3/20/2001
3/20/2001
Method Error
1
3/21/2001
3/21/2001
System Upset
After the exclusions were incorporated, more than 2,500 measurements of COD remained
and were used as the basis of the final limitations. Table 13-5 summarizes the data. The
statistical support memorandum (USEPA, 2010) provides a list and plots of the data.
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Table 13-5. COD: Summary of Albany Airport Self-Monitoring Effluent Data After
Exclusions
COD Coneentrations (mg/L)1
Unit
Season
# of
Days
Standard
Deviation
Minimum
Maximum
Median
Mean2
Season99
147
50.31
1
326
14.0
28.60
SeasonOO
112
71.93
2
575
64.0
75.46
SeasonOl
168
20.97
9
157
37.0
44.02
Season02
180
64.41
20
655
73.0
86.80
Season03
146
103.19
2
699
50.0
76.32
ArprtRlOl
Season04
140
30.76
2
275
25.0
31.51
Season05
90
18.08
8
162
29.5
31.56
Season06
62
24.08
1
136
17.0
23.10
Season07
124
98.07
9
1042
41.5
54.48
Season08
120
59.85
15
674
35.0
42.74
ALL
1289
66.67
1
1042
37.0
52.28
Season99
141
17.41
1
93
11.0
16.85
SeasonOO
117
51.50
11
393
55.0
63.09
SeasonOl
165
20.23
10
168
35.0
40.01
Season02
183
51.73
25
685
51.0
57.61
Season03
147
30.03
1
210
60.0
63.12
ArprtR_102
Season04
145
73.96
2
725
76.0
87.42
Season05
95
33.21
22
275
72.0
77.19
Season06
62
41.68
2
148
46.5
61.34
Season07
98
10.01
12
58
34.0
33.70
Season08
120
24.92
12
282
37.0
39.07
ALL
1273
45.65
1
725
45.0
53.40
In this summary, nondetected values are set equal to the detection limit.
2 The mean is calculated as the arithmetic average.
13.5 Ammonia: Data Selected as Basis of Final Limitation
For ammonia, EPA is promulgating a compliance alternative with a daily maximum
limitation for airports that use deicers containing urea on the runways. This section describes the
data selected as the basis of the final limitation for ammonia.
After evaluating the available data, EPA transferred the 1-day-lag serial correlation value
from the AFB technology, which is the model technology for COD. This transfer was necessary
because an AFB system by design creates ammonia as a by-product of wastewater treatment.
Consequently, AFB discharges could have higher ammonia concentrations than typically found
in airfield stormwater when airfield deicers containing urea are not used. If the treated aircraft
deicing stormwater discharges then were discharged to the same pipe as the runway wastewater,
the airport might have difficulties complying with the ammonia limitation. EPA also confirmed
that ADF treatment provided less concentrated discharges than observed from the application of
urea products (ERG. 2009). For these reasons, EPA determined that it was appropriate to use the
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ADF data as a basis of limitations that would apply to discharges associated with runway
deicing.
As it had for COD, EPA initially evaluated the Albany data for setting final limitations
for ammonia, because EPA had data on the performance of its model technology. In contrast to
its practice of monitoring COD at the end of each treatment unit, the airport monitored ammonia
at its permit compliance point after additional treatment provided by an aerobic polishing step.
The anaerobic polishing step would result in decreased ammonia concentrations and would not
represent ammonia discharges from using urea on airfields. Thus, to promulgate an effluent limit
consistent with the model technology, EPA used the EPA data and excluded the Albany
ammonia data (criterion 3).
Instead, because they reflect the capability of the model treatment system, EPA used its
sampling data from EPA SP-2, shown in Table 13-6, as the basis of the final ammonia
limitations. (Section 13.6 describes field duplicates and the importance of daily values for the
limitation calculations.) In analyzing samples from this episode, the laboratory achieved a
detection limit of 0.05 mg/L. During the laboratory's quality assurance step of the chemical
analysis, it detected ammonia in the laboratory preparation blank at a concentration of 0.069
mg/L. Other quality assurance parameters, initial calibration blanks and continuing calibration
blanks, were between 0.052 mg/L and 0.054 mg/L. The ammonia results for all samples are
greater than 10 times the blank result, with the exception of four influent and one source water
samples that were not used as the basis of the final limitation. Consequently, EPA determined
that the data were of acceptable quality to use as the basis of the final limitation.
Table 13-6. Ammonia: Data from Albany Airport Used to Develop Limitations
Sample Day
Ammonia Concentrations (mg/L)
Influent
Effluent
Original Sample
Field Duplicate
(where collected)
Daily Value Used in
Limitations Calculations
1
ND (0.1)
2.58
2.58
2
ND (0.1)
4.14
3.95
4.05
3
ND (0.1)
4.45
5.54
5.00
4
ND (0.1)
6.12
6.12
5
0.91
6.65
6.65
ND - Not Detected
13.6 Limitations: Basis and Calculations
The final limitations, as presented in the final rule, are provided as the daily maximum
limitations for COD and ammonia. In addition, the notice includes a weekly average limitation
for COD. This section defines the limitations (Section 13.6.1) and describes the statistical
percentile basis of the limitations (Section 13.6.2) and the estimation of the percentiles for COD
and ammonia (Sections 13.6.3). The statistical support memorandum (USEPA, 2010) describes
the calculations used to model the ammonia data.
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13.6.1 Definitions
Definitions provided in 40 CFR 122.2 describe the limitations in terms of "daily
discharge," which it defines as "the 'discharge of a pollutant' measured during a calendar day or
any 24-hour period that reasonably represents the calendar day for purposes of sampling."
Therefore, EPA generally arithmetically averages all measurements recorded for each uniquely
reported time period (e.g., 12/21/2004) before calculating limitations. EPA refers to this
averaged value as the "daily value."
First, in calculating the limitations, EPA ensures that it has only one value for each day.
Field duplicates are one example of multiple measurements, and were included in the ammonia
data used to develop the final limitations. Field duplicates are two samples collected at the same
sample point at approximately the same time, flagged as duplicates for a single sample point, and
measured separately. Because the analytical data from each duplicate pair characterize the same
conditions at that time at a single sample point, EPA typically averages the data to obtain one
data value for those conditions on that day. For example, Table 13-6 shows the field duplicates
and daily, averaged values for ammonia.
Second, EPA uses the daily values in calculating the limitations. Definitions provided in
40 CFR 122.2 further describe the "maximum daily discharge limitation" as the "highest
allowable 'daily discharge.'" The "average weekly discharge limitation" is the "highest
allowable average of 'daily discharges' over a calendar week, calculated as the sum of all 'daily
discharges' measured during a calendar week divided by the number of 'daily discharges'
measured during that week."
13.6.2 Percentile Basis of the Limitations
EPA uses a statistical framework to establish limitations that facilities are capable of
complying with at all times. Statistical methods are appropriate for dealing with effluent data
because the quality of effluent, even in well-operated systems, is subject to a certain amount of
fluctuation or uncertainty. Statistics is the science of dealing with uncertainty in a logical and
consistent manner. Statistical methods together with engineering analysis of operating
conditions, therefore, provide a logical and consistent framework for analyzing a set of effluent
data and determining values from the data that form a reasonable basis for effluent limitations.
Using statistical methods, EPA has derived numerical values for its final daily maximum
limitations and weekly average limitations.
The statistical percentiles upon which the limitations are based are intended to be high
enough to accommodate reasonably anticipated variability within control of the facility. The
limitations also reflect a level of performance consistent with the CWA requirement that these
limitations be based on the best technologies that are properly operated and maintained.
In establishing daily maximum limitations, EPA's objective is to restrict the discharges
on a daily basis at a level that is achievable for an airport that targets its treatment system design
and operation at the long-term average while allowing for the variability around the long-term
average that results from normal operations. This variability means that at certain times airports
may discharge at levels that are greater or considerably lower than the long-term average. To
allow for possibly higher daily discharges, EPA has established the daily maximum limitation at
a relatively high level (i.e., the 99th percentile). Due to routine variability in treated effluent, an
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airport that discharges consistently at a level near the daily maximum limitation, instead of the
long-term average, may experience frequent values exceeding the limitations. For this reason,
EPA recommends that airports target the treatment system at the long-term average that it
derived for the model technology.
In its derivation of the weekly average limitation for COD, EPA used an estimate of the
97th percentile of the weekly averages of the daily measurements. This percentile basis is the
midpoint of the percentiles used for the daily maximum limitation (i.e., 99th percentile of the
distribution of daily values) and the monthly average limitation (i.e., 95th percentile of the
distribution of monthly average values). Courts have upheld EPA's use of these percentiles, and
the selection of the 97th percentile is a logical extension of this practice. Compliance with the
daily maximum limitation is determined by a single daily value; therefore, EPA feels the 99th
percentile provides a reasonable basis for the daily maximum limitation by allowing for an
occasional extreme discharge. Because compliance with the monthly average limitation is based
upon more than one daily measurement and averages are less variable than daily discharges,
EPA has determined that facilities should be able to control the average of daily discharges to
avoid extreme monthly averages above the 95th percentile. Similar to the monthly average
limitation, compliance with the weekly average limitation also would be based upon more than
one daily measurement. However, the airport would monitor for a shorter time and thus would
have fewer opportunities to counterbalance highly concentrated daily discharges with lower
ones. For this reason, EPA is utilizing a larger percentile for the weekly average limitation than
the one used for the monthly average limitation. Consequently, EPA is using the 97th percentile
as an appropriate basis for limiting average discharges on a weekly basis. EPA also considers
this level of control in avoiding extreme weekly average discharges to be possible for airports
using the model technology.
13.6.3 Estimation Procedures for Percentiles
This section describes the estimation procedures that EPA used to calculate the
limitations for the final rulemaking. Sections 13.6.3.1, and 13.6.3.2 describe the estimation
procedures used to model the COD data and the June 8, 2009, memorandum on calculation of
percentiles (Westat. 2009) describes the calculations used by the statistical software. Section
13.6.3.3 describes the procedures for ammonia.
Table 13-7 summarizes the limitations that EPA established for COD and ammonia.
Because of the importance of targeting treatment to the long-term average, EPA recommends
that facilities design, maintain, and operate the treatment system to achieve a long-term average
of 52.8 mg/L, which is the median of the averages from the two units (52.28 mg/L for
ArprtR lOl and 53.40 for ArprtR_102, as shown in Table 13-5). The allowance for variability,
or the ratio of the limitation to the long-term average, is 5.13. (EPA usually refers to this
allowance as the "variability factor.") In other words, the daily maximum limitation is 5.13 times
greater than the long-term average achievable by the model technology. By targeting the system
to the long-term average and controlling its variability within this range, the facility will be able
to comply with the limitation.
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Table 13-7. COD and Ammonia: Final Limitations with Long-Term Averages and
Variability Factors
Parameter
Time Period
COD
Ammonia
Limitations (mg/L)
Daily Maximum
271
14.7
Weekly Average
154
NA
Long-Term Average (mg/L)
All
52.8
5.24
Variability Factors
Daily
5.13
2.81
Weekly
2.92
NA
NA - Not applicable
13.6.3.1 COD: Daily Maximum Limitation and the 99th Percentile
For COD, EPA based the final daily maximum limitation on an estimate of the 99th
percentile of the distribution of the daily values. This section describes the percentile estimates
and the long-term average.
First, EPA used nonparametric methods to estimate the 99th percentile of the daily values
from each unit. A simple nonparametric estimate of the 99th percentile of an effluent
concentration data set is the observed value that exceeds 99 percent of the observed data points.
Because EPA had more than 1,200 data points for each unit, it determined that the empirical
approach would provide reasonable estimates of the 99th percentiles.
Second, EPA set the final limitation equal to the median of the two 99th percentile
estimates, or 271 mg/L. The median is, by definition, the midpoint of all available data values
ordered (i.e., ranked) from smallest to largest. As result, half of the unit 99th percentiles are
higher than the median and half are lower. (In this particular case, because there are two units,
the median is equal to the arithmetic average (or mean).)
Table 13-8 summarizes the percentile estimates for the two units, the minimum and
maximum values observed in the data, the 50th percentiles, and the 99th percentiles.
Table 13-8. COD: 99th Percentile Estimates from Each Treatment Unit
Treatment Unit
Number of Dailv
Values
Concentrations (mg/L)
Minimum
50th Percentile
Maximum
99"' Percentile
ArprtR-101
1,289
1
37
1042
326
ArprtR-102
1,273
1
45
725
216
Median Values
41
271
13.6.3.2 COD: Weekly Average Limitation and the 97th Percentile
For the weekly average limitation of COD, EPA first calculated, for each unit, the
arithmetic average of the measurements observed during each week, excluding weekends (to be
consistent with the assumed monitoring costs, although permit authorities may specify different
monitoring requirements). EPA then used the nonparametric method to derive a 97th percentile of
the more than 200 weekly averages for each unit, and set the final limitation equal to the median
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of the two 97th percentile estimates, or 154 mg/L. The statistical support memorandum (USEPA,
2010) lists the weekly averages.
Because data were not always available for every weekday during a week, EPA examined
whether the weekly averages were affected by the number of weekdays included in the average.
As shown in Table 13-9, the value of the limitation varied only slightly if the weeks were
required to have data for all five days. The June 23, 2009, memorandum on percentiles for
weekly averages (Westat, 2009a) provides a more detailed evaluation.
Table 13-9. COD: Effect of Number of Daily Values in Weekly Averages
Number of Daily
Values in Average
Unit ArprtR-101
Unit AirprtR-102
Median of 97th
Percentiles
Number of
Weekly Averages
97th
Percentile
N u m ber of W eekly
Averages
97th
Percentile
5
155
176.8
157
133.6
155.2
4 or 5
181
176.8
181
133.6
155.2
1 to 5 1
209
162.4
203
145.5
153.95
Averages in this row were used as the basis of the final weekly average limitation.
13.6.3.3 Ammonia: Percentile Estimates Based Upon the Lognormal Distribution
Because the ammonia data set had fewer than 100 observations, EPA used a parametric
approach to model the data. If a data set comprisese fewer than 100 observations, the best that
can be done, using nonparametric methods, is to use the maximum value as an approximate
nonparametric estimate of the 99th percentile, but this can underestimate the true value.
Parametric methods require that a probability distribution be specified, which allows estimation
of unknown parameters from the available data. The estimated parameters are a function of the
defined distribution and the data, and thus the parametric method enables the percentiles of
effluent concentrations to be computed analytically. EPA's selection of parametric methods in
developing limitations for other industries is well documented (e.g., Iron and Steel, Pulp, Paper,
and Paperboard, and Metal Products and Machinery categories). EPA considers the lognormal
distribution to be appropriate for the ammonia data, and this section describes its application in
estimating the final daily maximum limitation. The daily maximum limitation of 14.7 mg/L is
based upon an estimate of the 99th percentile of the lognormal distribution of the daily values.
The calculations include an adjustment for possible bias due to statistical autocorrelation.
The adjusted variance then better reflects the underlying variability that would be present if the
data were collected over a longer period. When data are said to be positively autocorrelated, it
means that measurements taken at specific time intervals (such as 1 day or 2 days apart) are
similar. For example, positive autocorrelation would be present in the data if the final effluent
concentration was relatively high one day and was likely to remain at similar high values the
next and possibly succeeding days. EPA sampling data, used as the basis of the limitations, were
collected on five consecutive days, and thus, the data may be autocorrelated, but the length of
time was not sufficient for autocorrelation evaluations. Albany Airport's self-monitoring data
also were not suitable for the evaluation because they were collected at three-week intervals
rather than consecutive days. In contrast, the Iron and Steel rule had 244 data points for ammonia
that generally were collected on consecutive days, so it was possible to evaluate autocorrelation
in the data. Because the model technologies for both industries are biological systems, EPA
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Section 13 - Limitations and Standards: Data Selection and Calculation
concludes that the Iron and Steel autocorrelation adjustment is a reasonable transfer that can be
used to calculate the airport deicing limitations.10 Table 13-10 summarizes the final long-term
average and daily maximum limitation, with and without the adjustment for autocorrelation. The
final daily maximum limitation of 14.7 mg/L is 2.8 times greater than the long-term average, of
5.24 mg/L, achievable by the model technology. By targeting the system to the long-term
average and controlling its variability within this range, the facility will be able to comply with
the limitation. However, ammonia is generated as a by-product of the model technology, and
EPA expects the concentrations of ammonia to have similar variability to what is being treated
(i.e., COD). In contrast to the COD limitations, which are based on a mixture of start-up and
steady-state periods, the ammonia limitation is based upon data collected only during steady-
state operations.
Table 13-10. Ammonia: Consideration of Autocorrelation for Final Limitations, Long-
Term Averages, and Variability Factors
Statistical Parameter
Adjusted for Autocorrelation?
Percent
Difference
No
Yes (Final)
Long-Term Average (mg/L)
4.97
5.24
5%
Variability Factor
2.25
2.81
25%
Daily Maximum Limitation (mg/L)
11.2
14.7
31%
Unlike COD, EPA is not setting a weekly ammonia effluent limitation. The technology
basis for the COD effluent limitations would operate throughout the deicing season with
continuous discharges allowing for weekly monitoring. In contrast, urea is applied to airfield
pavement as needed, and discharges would occur for a short time after the initial application, as
the urea works its way through the stormwater collection and any associated treatment system
that may be present. Most airports would have noncontinuous and somewhat infrequent urea
discharges. Consequently, it would be difficult to assume a single value for the monitoring
frequency that could reasonably be applied to all airports, regardless of climatic conditions.
13.6.3.4 Significant Digits for Final Limitations
In presenting the values of the final limitations, EPA rounded the values to three
significant digits. EPA used a rounding procedure where values of five and above are rounded up
and values of four and below are rounded down. For example, a value of 5.235 would be
rounded to 5.24, while a value of 5.234 would be rounded to 5.23.
13.7 Achievabilitv of Limitations
EPA promulgates limitations that sites are capable of complying with at all times by
properly operating and maintaining their processes and treatment technologies. As a consequence
of using the percentile basis for each final limitation, treatment systems that are designed and
operated to achieve long-term average levels should be able to comply with the limitations,
which incorporate variability, at all times. As verification that the limitations are achievable,
10 EPA has not incorporated a similar adjustment for autocorrelation into the data for the COD limitations because
the limitation is based upon more than 2500 measurements collected over 10 years, which presumably would show a
full range of variability expected by the model technology. (DCNs AD01210 and AD01214)
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Section 13 - Limitations and Standards: Data Selection and Calculation
EPA performs additional statistical and engineering reviews, as described in Section 13.7.1. As a
result of these reviews, EPA has concluded that these limitations are achievable, and thus EPA
expects facilities to comply with the limitations as explained in Section 13.7.2.
13.7.1 Statistical and Engineering Review of Limitations
In conjunction with the statistical methods, EPA performs an engineering review to
verify that the limitations are reasonable based upon the design and expected operation of the
control technologies and the airport conditions. The following sections describe two types of
comparisons. First, EPA compares the final limitations to the data used to develop the
limitations. Second, EPA compares the limitations to the influent data.
13.7.1.1 Comparison to Data Used As Basis for the Limitations
As part of its data evaluations, EPA compared the value of the final limitations to the
values used to calculate the limitations. None of the data selected for ammonia were greater than
its final daily maximum limitation that supports the engineering and statistical conclusions that
the limitation values are appropriate. Because of the statistical methodology used for the COD
limitations, some values were greater than the final limitations.
For COD, appropriately one percent of the values were greater than the final daily
maximum limitation, which is consistent with the statistical basis (i.e., use of the 99th percentile)
of the limitation. Table 13-11 lists the data from both units and the influent, when one or both
effluent values were greater than the limitation. Of the 27 values greater than the final limitation,
20 were from the ArprtR-101 unit, and 7 from ArprtR-102 unit. Both units had values greater
than the final limitation on three dates: 3/31/2001, 1/4/2005, and 12/25/2008.
Of the 412 weekly averages of the COD concentrations, 12 averages had values that were
greater than the final weekly average limitation of 154 mg/L. Of those 12 averages, 10 were
during weeks when the unit also had one or more daily values that were greater than the daily
maximum limitation. The statistical support memorandum (USEPA, 2010) identifies the weeks
and the corresponding daily values.
13.7.1.1 Comparison to Influent
In addition to evaluating the data used as the basis of the limitations, EPA often compares
the value of the final limitations to influent concentration levels. In these comparisons, EPA
determines if the limitations perform as expected.
As part of its evaluation to determine if the COD limitation was sufficiently stringent to
require that the influent be treated, EPA evaluated the COD influent discharges from Albany
Airport. As shown in the summary statistics in Table 13-12, all influent values were greater than
the final limitation during nine deicing seasons. For the season 06, only two values (1/1/2007 and
1/2/2007) were less than the final limitation.11 This finding confirmed that the final limitation
can only be met through treatment.
11 For both dates, the facility reported the same values for influent (100 mg/L), the same values for ArprtR-101 (30
mg/L), and the same estimated values for ArprtR-102.
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Table 13-11. COD: Dates and Values Greater than Final Limitation of 271 mg/L
Season
Date
COD Coneentrations (mg/L)1
ArprtR 101
ArprtR 102
Season99
16MAR2000
326
33
23MAR2000
315
93
SeasonOO
01MAR2001
276
232
11MAR2001
288
64
12MAR2001
575
92
22MAR2001
129
393
31MAR2001
357
288
Season02
18MAY2003
(Estimated to be 800)2
685
19MAY2003
460
95
20MAY2003
655
86
22MAY2003
290
101
Season03
20DEC2003
278
2
03JAN2004
690
36
08JAN2004
387
37
08FEB2004
435
74
09FEB2004
453
49
16MAR2004
316
124
17MAR2004
699
118
Season04
04JAN2005
275
725
04FEB2005
38
360
Season05
09DEC2005
162
275
Season07
09JAN2008
1,042
Out of service
10JAN2008
433
Out of service
Season08
25DEC2008
674
282
Bold text indicates effluent values greater than the limitations.
2This value was not used in calculating the limits because it was an estimated value (see DCN AD01246)
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Table 13-12. COD: Summary Statistics of Influent Concentrations
Season
#of Days
COD: Influent Concentration (mg/L)
Standard
Deviation
Minimum
Maximum
Median
Arithmetic
Average
Season99
141
1,536
1,000
6,560
2,784
3,242
SeasonOO
115
1,257
1,797
7,950
5,505
5,208
SeasonOl
167
1,505
342
7,105
3,975
3,949
Season02
187
1,825
2,915
10,470
7,270
7,144
Season03
145
2,412
655
10,060
6,520
5,996
Season04
141
1,790
1,848
8,870
5,580
5,272
Season05
85
1,685
528
7,410
4,900
4,373
Season06
62
1,700
100
5,760
1,880
2,588
Season07
127
2,132
485
11,000
7,540
6,805
Season08
120
4,409
3,550
18,300
8,875
10,022
ALL
1,290
2,928
100
18,300
5,490
5,630
13.7.2 Compliance with Limitations
EPA promulgates limitations that sites are capable of complying with at all times by
properly operating and maintaining their processes and treatment technologies. However, the
issue of exceedances or excursions (values that exceed the limitations) is often raised. In other
rules, including EPA's final OCPSF rule, commenters suggested that EPA include a provision
that a facility is in compliance with permit limitations provided its discharge does not exceed the
specified limitations, with the exception that the discharge may exceed the daily maximum
limitation 1 day out of 100. EPA's general approach in that case for developing limitations based
on percentiles was the same as this rule and was upheld in Chemical Manufacturers Association
v. U.S. Environmental Protection Agency, 870 F.2d 177, 230 (5th Cir. 1989). The Court
determined the following:
EPA reasonably concluded that the data points exceeding the 99th and 95th
percentiles represent either quality-control problems or upsets because there can
be no other explanation for these isolated and extremely high discharges. If these
data points result from quality-control problems, the exceedances they represent
are within the control of the plant. If, however, the data points represent
exceedances beyond the control of the industry, the upset defense is available.
Id. at 230.
This issue also was raised in EPA's Phase I rule for the Pulp, Paper, and Paperboard
Category (USEPA, 1998). In that rulemaking, EPA used the same general percentile approach
for developing monthly average limitations that it used for daily maximum limitation for the
airport deicing rule. The percentile approach for the monthly average limitation was upheld in
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National Wildlife Federation et al. v. Environmental Protection Agency, 286 F.3d 554, 573 (D.C.
Cir. 2002). The Court determined that:
EPA's approach to developing monthly limitations was reasonable. It established
limitations based on percentiles achieved by facilities using well-operated and
controlled processes and treatment systems. It is therefore reasonable for EPA to
conclude that measurements above the limitations are due to either upset
conditions or deficiencies in process and treatment system maintenance and
operation. EPA has included an affirmative defense that is available to mills that
exceed limitations due to an unforeseen event. EPA reasonably concluded that
other exceedances would be the result of design or operational deficiencies. EPA
rejected Industry Petitioners' claim that facilities are expected to operate
processes and treatment systems to violate the limitations at some pre-set rate.
EPA explained that the statistical methodology was used as a framework to
establish the limitations based on percentiles. These limitations were never
intended to have the rigid probabilistic interpretation that Industry Petitioners
have adopted. Therefore, we reject Industry Petitioners' challenge to the effluent
limitations.
As that Court recognized, EPA's allowance for reasonably anticipated variability in its
effluent limitations, coupled with the availability of the upset defense, reasonably accommodates
acceptable excursions. Any further excursion allowances would go beyond the reasonable
accommodation of variability and would jeopardize the effective control of pollutant discharges
on a consistent basis and/or bog down administrative and enforcement proceedings in detailed
fact-finding exercises, contrary to Congressional intent. See, for example, Rep. No. 92-414, 92d
Congress, 2d Sess. 64, reprinted in A Legislative History of the Water Pollution Control Act
Amendments of1972 (at 1482); Legislative History of the Clean Water Act of 1977 (at 464-65).
More recently, for EPA's rule for the iron and steel industry, EPA's selection of
percentiles was upheld in American Coke and Coal Chemicals Institute v. Environmental
Protection Agency, 452 F.3d 930, 945 (D.C. Cir. 2006). The Court determined that:
The court will not second-guess EPA's expertise with regard to what the
maximum effluent limits represent. See Nat'l Wildlife, 286 F.3d at 571-73. As
EPA explains in the Final Development Document, the daily and monthly average
effluent limitations are not promulgated with the expectation that a plant will
operate with an eye toward barely achieving the limitations. Final Development
Document at ง 14.6.2. Should a plant do so, it could be expected to exceed these
limits frequently because of the foreseeable variation in treatment effectiveness.
Rather, the effluent limitations are promulgated with the expectation that plants
will be operated with an eye towards achieving the equivalent of the long term
average for the BAT-1 model technology. Id. However, even operated with the
goal of achieving the BAT-1 long term average, a plant's actual results will vary.
EPA's maximum daily limitations are designed to be forgiving enough to cover
the operations of a well-operated model facility 99% of the time, while its
maximum monthly average limitations are designed to be forgiving enough to
accommodate the operations of a well-operated model facility 95% of the time.
See id. EPA's choice of percentile distribution represented by its maximum
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effluent limitation under the CWA represents an expert policy judgment that is
not arbitrary or capricious.
EPA expects that airports will comply with promulgated limitations at all times. If an
exceedance is caused by an upset condition, the airport would be able to defend against an
enforcement action if it meets the requirements of 40 CFR 122.41(n). If the exceedance is caused
by a design or operational deficiency, EPA has determined that the airport's performance does
not represent the appropriate level of control (best available technology for existing sources; best
available demonstrated technology for new sources). For promulgated limitations and standards,
EPA has determined that such exceedances can be controlled by diligent process and wastewater
treatment system operational practices such as frequent inspection and repair of equipment, use
of backup systems, and operator training and performance evaluations.
13.8 References
ERG. 2008. Personnel communication (email) between Mary Willett (ERG) and Mark Sober,
Albany International Airport. (July 22). DCN AD00824.
ERG. 2008a. Email from Mark Sober (Albany International Airport) to Mary Willett (ERG). RE:
One More Query. (July 22). DCN AD01206.
ERG. 2008b. Telecon between Cortney Itle (ERG) and Mark Sober (Albany International
Airport). RE: ALB Follow-up Questions. (August 14). DCN AD00825.
ERG. 2009. Memorandum from Mary Willett (ERG) to Brian D'Amico (EPA). Evaluation of
Proposed Compliance Alternative Ammonia Limitations with respect to Airport Deicing
Stormwater Typical Ammonia Discharges. (June 30). DCN ADO 1194.
USEPA. 1987. Organic Chemicals and Plastics and Synthetic Fibers Category Effluent
Limitations Guidelines, Pretreatment Standards and New Source Performance Standards; Final
Rule. 40 CFR Part 414, 52 FR 42522, November 5, 1987.
USEPA. 1998. National Emission Standards for Hazardous Air Pollutants for Source Category:
Pulp and Paper Production; Effluent Limitations Guidelines, Pretreatment Standards, and New
Source Performance Standards: Pulp, Paper, and Paperboard Category; Final Rule. 40 CFR
Part 430, 63 FR 18503, April 15, 1998.
USEPA. 2002. Development Document for Effluent Limitations Guidelines and Standards for the
Iron and Steel Manufacturing Point Source Category. EPA-821-R-02-004. Section 14.1.
Available online atwww.epa.gov/guide/ironsteel/.
USEPA. 2006. Notice of Availability of Final 2006 Effluent Guidelines Program Plan.
December 21, 2006; 71 FR 76655.
USEPA. 2010. Memorandum from Cue Schroeder (EPA) to Brian D'Amico (EPA). Statistical
Support Memorandum. (November). DCN AD01246.
Westat. 2009. Memorandum from John Rogers (Westat) to Maria Smith (EPA). Calculation
Percentiles. (June 8). DCN AD01213.
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Westat. 2009a. Memorandum from John Rogers (Westat) to Maria Smith (EPA). Percentiles for
Weekly Averages. (June 23). DCN AD01214.
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