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EO12866_AirptDeicingEffGdl_2040-AE69 FR FRN_20110525.docx 

ENVIRONMENTAL PROTECTION AGENCY 

40 CFR Part 122 

40 CFR Part 449 

[EPA-HQ-OW-2004-0038. FRL- ] 

RIN 2040-AE69 

Effluent Limitation Guidelines and New Source Performance Standards for the Airport Deicing 

Category 

AGENCY: Environmental Protection Agency (EPA). 

ACTION: Final Rule. 

SUMMARY: EPA is promulgating technology-based effluent limitation guidelines (ELGs) and 

new source performance standards (NSPS) under the Clean Water Act (CWA) for discharges 

from airport deicing operations. The requirements generally apply to wastewater associated with 

the deicing of aircraft and airfield pavement at primary airports. The rule will require all such 

airports to comply with requirements based on discontinuing use of pavement deicers containing 

urea in favor of less toxic products or, alternatively, to meet ammonia limits for their direct 

discharges. The rule will require a subset of these airports, those that use greater than or equal to 

60,000 gallons of normalized ADF per deicing season, to meet requirements based on collection 

of deicing fluid and treatment of the collected fluid. The ELGs will be incorporated into 

NPDES permits issued by EPA or states. EPA expects compliance with this regulation to reduce 

the discharge of deicing-related pollutants by 33 million pounds per year. EPA estimates the 

annual cost of the rule is $78 million. 

DATES: This final rule is effective on [insert 30 days after publication in the Federal Register]. 

ADDRESSES: EPA has established a docket for this action under Docket ID No. EPA–HQ–

OW–2004–0038. All documents in the docket are listed on the website at 
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http://www.regulations.gov. Although listed in the index, some information is not publicly 

available, e.g., CBI or other information whose disclosure is restricted by statute. Certain other 

material, such as copyrighted material, is not placed on the Internet and will be publicly available 

only in hard copy form. Publicly available docket materials are available either through the 

docket website or in hard copy at the Office of Water Docket, EPA West Building Room 3334, 

1301 Constitution Ave, NW, Washington, DC. The Public Reading Room is open from 8:30 

a.m. to 4:30 p.m., Monday through Friday, excluding legal holidays. The telephone number for 

the Public Reading Room is 202-566-1744, and the telephone number for the Office of Water 

Docket is 202-566-1752. 

FOR FURTHER INFORMATION CONTACT:

Eric Strassler, Engineering and Analysis Division, telephone: 202-566-1026; e-mail: 

strassler.eric@epa.gov. 

SUPPLEMENTARY INFORMATION: 

Regulated Entities 

Entities regulated by this action include: 

Category Example of Regulated Entity North American Industry 

Classification System Code 

Industry Primary airports 481, 4881 

 This section is not intended to be exhaustive, but rather provides a guide for readers 

regarding entities likely to be regulated by this action. Other types of entities that do not meet 

the above criteria could also be regulated. To determine whether your facility is regulated by 

this action, you should carefully examine the applicability criteria listed in §449.01 and the 
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definitions in §449.02 of the rule and detailed further in Section V of this preamble. If you still 

have questions regarding the applicability of this action to a particular entity, consult one of the 

persons listed for technical information in the preceding FOR FURTHER INFORMATION 

CONTACT section. 

Supporting Documentation 

 Today’s final rule is supported by a number of documents including: 

 Technical Development Document for Final Effluent Limitation Guidelines and 

Standards for the Airport Deicing Category (TDD), Document No. EPA-821-R-_____; 

 Economic Analysis for Final Effluent Limitation Guidelines and Standards for the 

Airport Deicing Category (EA), Document No. EPA-821-R-______; 

 Environmental Impact and Benefit Assessment for Final Effluent Limitation Guidelines 

and Standards for the Airport Deicing Category (EIB), Document No. EPA-821-R-

______. 

These documents are available in the public record for this rule and on EPA’s website at 

http://epa.gov/guide/airport . 

Overview 

 The preamble describes the terms, acronyms, and abbreviations used in this notice; the 

background documents that support the regulations; the legal authority of these rules; a summary 

of the final rule; background information; and the technical and economic methodologies used 

by the Agency to develop these regulations. 

Table of Contents 

I. Legal Authority 6

II. Purpose and Summary of the Final Rule 7

III. Background 7

A. Clean Water Act 7
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B. NPDES Permits 9

1. General Permits 10

2. Individual Permits 11

C. Effluent Guidelines and Standards Program 12

1. Best Practicable Control Technology Currently Available (BPT) 12

2. Best Conventional Pollutant Control Technology (BCT) 13

3. Best Available Technology Economically Achievable (BAT) 13

4. New Source Performance Standards (NSPS) 14

5. Pretreatment Standards for Existing Sources (PSES) 14

6. Pretreatment Standards for New Sources (PSNS) 15

D. Proposed Rule 15

1. ADF Collection 16

2. Numeric Limit for Collected ADF 17

3. Airfield Pavement Deicers 17

4. Other Technology Basis Considered 17

IV. Summary of Significant Comments and Changes to Rule Since Proposal 17

A. ADF Collection Requirements and Applicability 17

1. Applicability of ADF Collection/Discharge Requirement for Existing Sources 18

2. Collection Requirement 20

B. New Source Definition and ADF Collection Requirement Applicability 22

C. Extension of Applicability Date 24

D. Deicing for Safe Taxiing 26

E. Glycol Collection Vehicles 26

F. Effluent Limitation for Chemical Oxygen Demand 27

1. COD as an Indicator for ADF 27

2. Arguments that EPA Must Address BOD5 31

3. COD Versus Soluble COD as a Regulated Pollutant 34

V. Scope and Applicability of the Final Rule 34

A. Subcategorization 35

B. Industry Description 36

C. Wastewater Sources and Wastewater Characteristics 38

1. Aircraft Deicing 38

2. Airfield Pavement Deicing 39

D. Control and Treatment Technologies for the Aviation Industry 40

1. Aircraft Deicing Fluid Collection Technologies 41

2. ADF-Contaminated Wastewater Treatment Technologies 43

3. Pollution Prevention Technologies 44

4. Airfield Pavement Deicing Control Technologies 47

E. Regulated Pollutants 47

VI. Final Regulation 47

A. BPT and BCT 47

B. BAT 48

1. Airfield Deicing: Product Substitution of Pavement Deicers Containing Urea 48

2. Aircraft Deicing: ADF Collection Requirements and Effluent Limitations 50

3. BAT Options Selection 53

C. NSPS 54
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D. PSES and PSNS 55

VII. Technology Costs and Pollutant Reductions 57

A. Compliance Costs 57

1. Overview 57

2. Approach for Estimating Airfield Pavement Deicing Costs 58

3. Approach for Developing Aircraft Deicing Costs 59

4. Calculation of National Costs 61

B. Approach to Estimating Pollutant Reductions 62

1. Overview 62

2. Sources and Use of Available Data 63

C. Approach to Determining Long-Term Averages, Variability Factors and Effluent 

Limitation Guidelines and Standards 68

1. Criteria Used to Select Data as the Basis of the Limitations 68

2. Data Used As Basis of the Effluent Limitations 70

3. Statistical Percentile Basis for Limitations 71

4. Rationale for Establishing Limitation on Weekly Averages Instead of Monthly Averages 

for COD in Effluent Discharges 73

5. Rationale for Promulgating a Limitation Only for Daily Discharges of Ammonia in 

Effluent Discharges 74

6. Calculation of Limitations for COD and Ammonia 75

7. Derivation of Long-Term Average for COD and Ammonia: Target Level for Treatment

76

8. Engineering Review of Effluent Limitations 77

VIII. Economic Analysis 79

A. Introduction 79

B. Annualized Compliance Cost Estimates 79

C. Economic Impact Methodologies 82

1. Cost Annualization 83

2. Airport Impact Methodology 84

3. Co-Permittee Airline Impact Methodology 88

D. Results of Impact Analysis 92

1. Results of Airport Impact Analysis 92

2. Results of Co-permittee Airline Impact Analysis 97

3. Economic Achievability 98

E. Economic Impacts for New Sources 100

F. Cost and Pollutant Reduction Comparison 102

G. Small Business Analysis 103

IX. Environmental Assessment 105

A. Environmental Impacts 105

B. Environmental Benefits 107

X. Non-Water Quality Environmental Impacts 108

A. Energy Requirements 108

B. Air Emissions 110

1. Emissions from GCV Collection 110

2. Emissions from AFB Treatment Systems 111

C. Solid Waste Generation 111
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XI. Regulatory Implementation 112

A. Relation of ELGs to NPDES Permits 112

B. Applicability Date 113

C. Demonstrating Compliance with the ADF Collection Requirement 113

D. Permit Application Requirements 116

E. COD Effluent Monitoring for Direct Dischargers 116

Direct dischargers are required by the final rule to sample and analyze the discharges from 

their treatment system for COD prior to any dilution or co-mingling with other non-deicing 

waters. The sampling frequency, analytical method and reporting procedures are determined 

by the permit authority. Permittees must follow the sampling protocol specified in Appendix 

A of Part 449. 116

F. Alternative Compliance Option for Pavement Deicers Containing Urea 116

G. Best Management Practices 117

H. Upset and Bypass Provisions 117

I. Variances and Modifications 118

1. Fundamentally Different Factors Variance 118

2. Economic Variances 120

3. Water Quality Variances 120

J. Information Resources 120

XII. Statutory and Executive Order Reviews 121

A. Executive Order 12866: Regulatory Planning and Review and Executive Order 13563: 

Improving Regulation and Regulatory Review 121

B. Paperwork Reduction Act 121

C. Regulatory Flexibility Act 123

D. Unfunded Mandates Reform Act 124

E. Executive Order 13132: Federalism 125

F. Executive Order 13175: Consultation and Coordination with Indian Tribal Governments

126

G. Executive Order 13045: Protection of Children from Environmental Health and Safety 

Risks 126

H. Executive Order 13211: Energy Effects 126

I. National Technology Transfer Advancement Act 127

J. Executive Order 12898: Federal Actions to Address Environmental Justice in Minority 

Populations and Low-Income Populations 127

K. Congressional Review Act 128

Appendix A: Abbreviations and Definitions Used in This Document 128

I. Legal Authority 

 EPA is promulgating this regulation under the authorities of sections 301, 304, 306, 308, 

402 and 501 of the Clean Water Act (CWA), 33 U.S.C. 1311, 1314, 1316, 1318, 1342 and 1361 

and pursuant to the Pollution Prevention Act of 1990, 42 U.S.C. 13101 et seq. 
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II. Purpose and Summary of the Final Rule 

 Commercial airports and air carriers conduct deicing operations as required by the 

Federal Aviation Administration (FAA). Airport discharges from deicing operations may affect 

water quality in surrounding communities, including reductions in dissolved oxygen, fish kills, 

reduced organism abundance and species diversity, contamination of drinking water sources 

(both surface and groundwater), creation of noxious odors and discolored water in residential 

areas and parkland, and other effects. 

 Today EPA is promulgating effluent limitation guidelines (ELGs) and new source 

performance standards (NSPS) for the Airport Deicing Point Source Category. The regulations 

address control of the wastewater discharges from deicing operations based on product 

substitution, wastewater collection practices used by airports, and treatment practices for the 

collected wastewater. Certain airports within the scope of this rule are required to collect spent 

aircraft deicing fluid (ADF) and meet numerical discharge limits. Those airports and certain 

additional airports performing airfield pavement deicing are to use non-urea-containing deicers, 

or alternatively, meet a numeric effluent limitation for ammonia. The requirements are 

implemented in CWA discharge permits. 

 The rule requirements and the technologies that serve as the basis for the ELGs are 

explained in Sections V, VI and VII of this preamble. 

III. Background 

A. 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 
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biological integrity of the nation's waters.” (33 U.S.C. 1251(a)). The CWA establishes a 

comprehensive program for protecting our nation's waters. Among its core provisions, the CWA 

prohibits the discharge of pollutants from a point source to waters of the U.S. except as 

authorized under the CWA. Under section 402 of the CWA, EPA authorizes discharges by a 

National Pollutant Discharge Elimination System (NPDES) permit. The CWA also authorizes 

EPA to establish national technology-based effluent limitation guidelines and standards (effluent 

guidelines or ELGs) for discharges from different categories of point sources, such as industrial, 

commercial and public sources. 

In addition, the CWA authorizes EPA to promulgate nationally applicable pretreatment 

standards that restrict pollutant discharges from facilities that discharge wastewater indirectly 

through sewers flowing to publicly owned treatment works (POTWs). See section 307(b) and 

(c), 33 U.S.C. 1317(b) and (c). National pretreatment standards are established for those 

pollutants in wastewater from indirect dischargers that may pass through, interfere with or are 

otherwise incompatible with POTW operations. Generally, pretreatment standards are designed 

to ensure that wastewaters from direct and indirect industrial dischargers are subject to similar 

levels of treatment. In addition, POTWs are required to implement local treatment limits 

applicable to their industrial indirect dischargers to satisfy any local requirements. See 40 CFR 

403.5. 

Direct dischargers must comply with effluent limitations in NPDES permits. Indirect 

dischargers, who discharge through POTWs, must comply with pretreatment standards. 

Technology-based effluent limitations in NPDES permits are derived from effluent limitation 

guidelines (CWA sections 301 and 304, 33 U.S.C. 1311 and 1314) and new source performance 

standards (sec. 306) promulgated by EPA, or based on best professional judgment where EPA 
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has not promulgated an applicable effluent guideline or new source performance standard (CWA 

section 402(a)(1)(B), 33 U.S.C. 1342(a)(1)(B)). Additional limitations based on water quality 

standards (CWA section 301(b)(1)(C), 33 U.S.C. 1311(b)(1)(C)) are also required to be included 

in the permit in certain circumstances. The ELGs are established by regulation for categories of 

industrial dischargers and are based on the degree of control that can be achieved using various 

levels of pollution control technology. 

EPA promulgates national effluent limitation guidelines and standards of performance for 

major industrial categories for three classes of pollutants: (1) conventional pollutants (i.e., total 

suspended solids, oil and grease, biochemical oxygen demand, fecal coliform, and pH); (2) toxic 

pollutants (e.g., toxic metals such as chromium, lead, nickel, and zinc; toxic organic pollutants 

such as benzene, benzo-a-pyrene, phenol, and naphthalene); and (3) non-conventional pollutants 

(e.g., ammonia-N, formaldehyde, and phosphorus). 

B. NPDES Permits 

 Section 402 of the CWA requires permits for point source discharges of pollutants to 

waters of the United States. In most states, the permits are issued by a state agency that has been 

authorized by EPA. Currently 46 states and 1 U.S. territory are authorized to issue NPDES 

permits. In the other states and territories, EPA issues the permits. 

 Section 402(p) of the Act, added by the Water Quality Act of 1987 (Pub. L. 100-4, 

February 4, 1987), requires stormwater dischargers “associated with industrial activity” to be 

covered under an NPDES permit. In its initial stormwater permit regulations, called the “Phase 

I” stormwater regulations (55 FR 47990, November 16, 1990), EPA designated air transportation 

facilities, including both airlines and airports, which have vehicle maintenance shops (including 

vehicle rehabilitation, mechanical repairs, painting, fueling, and lubrication), equipment cleaning 
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operations, or airport deicing operations as subject to NPDES stormwater permitting 

requirements. See 40 CFR 122.26(b)(14)(viii). 

 Airport stormwater discharges may be controlled under a general NPDES permit, which 

covers multiple facilities with similar types of operations and/or wastestreams, or by an 

individual permit. (An airport may have additional NPDES permits for non-stormwater 

discharges, such as from equipment repair and maintenance facilities. The following discussion 

pertains only to airport stormwater permits.) 

1. General Permits 

 Currently most airport deicing discharges are covered by a general permit issued either 

by EPA or by an NPDES-authorized state agency. In most areas where EPA is the permit 

authority, the Multi-Sector General Permit (MSGP) covers airport deicing discharges (73 FR 

56572, September 29, 2008). Many NPDES-authorized state agencies have issued general 

permits in their respective jurisdictions with requirements similar to the MSGP. An airport 

seeking coverage under a general permit submits a Notice of Intent (NOI) to the permit authority 

rather than a detailed permit application. By submitting an NOI, the permittee is agreeing to 

comply with the conditions in the final general permit. 

 For airports, the major requirements of the current MSGP are: 

 develop a stormwater pollution prevention plan (SWPPP), including a drainage area site 

map, documentation of measures used for management of deicing contaminated 

stormwater, an evaluation of runway and aircraft deicing operations, and implementation 

of a program to control or manage deicing contaminated stormwater, including 

consideration of various listed control practices; 
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 implement deicing source reduction measures, including minimizing or eliminating the 

use of urea and glycol-containing deicing chemicals; minimizing contamination of 

deicing contaminated stormwater from runway and aircraft deicing operations; evaluating 

whether over-application of deicing chemicals occurs; and consider use of various listed 

source control measures; 

 for airports using over 100,000 gallons of glycol-based deicing chemicals and/or 100 tons 

or more of urea containing deicers annually, monitor discharges quarterly for the first 

four quarters of the permit cycle, for the following pollutants: biochemical oxygen 

demand (BOD5), chemical oxygen demand (COD), ammonia and pH; 

 if the average of the four monitoring values for any parameter exceeds its benchmark, 

implement additional control measures where feasible, and continue monitoring; 

 conduct an annual site inspection during the deicing season, and during periods of actual 

deicing operations if possible; and routine facility inspections at least monthly during the 

deicing season. 

 EPA expects to modify the MSGP when the next permit is issued, to conform to today’s 

final Airport Deicing rule. 

2. Individual Permits 

 Some EPA and state NPDES-permitting authorities have required certain airports to 

obtain individual permits. In these situations, an airport must submit a detailed application and 

the permit authority develops specific requirements for the facility. 

 Some individual permits contain specialized requirements for monitoring and/or best 

management practices. Some of these permits also contain numeric water quality-based effluent 
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limitations (WQBELs). Information on water quality-based permitting is available on EPA's 

website at http://cfpub.epa.gov/npdes/generalissues/watertechnology.cfm . 

C. Effluent Guidelines and Standards Program 

 Effluent guidelines and new source performance standards are technology-based 

regulations that are developed by EPA for a category of dischargers. These regulations are based 

on the performance of control and treatment technologies. The legislative history of CWA 

section 304(b), which is the heart of the effluent guidelines program, describes the need to press 

toward higher levels of control through research and development of new processes, 

modifications, replacement of obsolete plans and processes, and other improvements in 

technology, taking into account the cost of controls. Congress also stated that EPA need not 

consider water quality impacts on individual water bodies as the guidelines are developed. See 

Statement of Senator Muskie (Oct. 4, 1972), reprinted in Legislative History of the Water 

Pollution Control Act Amendments of 1972, at 170. (U.S. Senate, Committee on Public Works, 

Serial No. 93-1, January 1973.) 

 There are four types of standards applicable to direct dischargers (dischargers to surface 

waters), and two standards applicable to indirect dischargers (discharges to publicly owned 

treatment works or POTWs). 

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 non-conventional 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 
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benefits. The Agency also considers the age of the equipment and facilities, the processes 

employed, engineering aspects of the control technologies, any required process changes, nonwater quality environmental impacts (including energy requirements), and such other factors as 

the Administrator deems appropriate. See CWA sec. 304(b)(1)(B). If, however, existing 

performance is uniformly inadequate, EPA may establish limitations based on higher levels of 

control than 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. 

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 “costreasonableness” 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 measured over five days (BOD5), total suspended solids (TSS), 

fecal coliform, pH, and any additional pollutants defined by the Administrator as conventional. 

The Administrator designated oil and grease as an additional conventional pollutant on July 30, 

1979 (44 FR 44501; 40 CFR 401.16). 

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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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 on the basis of 

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. 

4. New Source Performance Standards (NSPS) 

 New Source Performance Standards reflect effluent reductions that are achievable based 

on the best available demonstrated control technology (BADCT). Owners of 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 

(that is, 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. 

5. Pretreatment Standards for Existing Sources (PSES) 
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 Section 307(b) calls for EPA to issue pretreatment standards for discharges of pollutants 

to publicly owned treatment works (POTW). Pretreatment Standards for Existing Sources 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 technologybased and are analogous to BPT and BAT effluent limitation guidelines. See CWA sections 

301((b)(1)(B) and 301(b)(2)(A)), 33 U.S.C. 1311(b)(1)(B) and 1311(b)(2)(A). 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 non-domestic dischargers. See 52 FR 1586 (Jan. 14, 1987). 

6. Pretreatment Standards for New Sources (PSNS) 

 Section 307(c) of the Act calls for EPA to promulgate pretreatment standards for new 

sources. 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 pretreatment standards for new sources based on best available demonstrated 

technology for new sources. New indirect dischargers have the opportunity to incorporate into 

their facilities the best available demonstrated technologies. The Agency typically considers the 

same factors in promulgating PSNS as it considers in promulgating NSPS. 

D. Proposed Rule 

 EPA published a proposed rule for the Airport Deicing Category on August 28, 2009 (74 

FR 44676). The proposed rule covered primary commercial airports that conduct deicing 

operations and have 1,000 or more annual jet departures. An existing airport in the scope of the 

proposal would have been required to certify that it uses airfield pavement deicers that do not 
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contain urea, or alternatively, meet an effluent limitation for ammonia. Additionally, in-scope 

airports with 10,000 or more annual departures would have been required to: 

 Collect at least a specified proportion (either 20 or 60 percent, based on size) of available 

aircraft deicing fluid (ADF) after it is sprayed on aircraft; and 

 Meet a specified numeric effluent limit for ADF wastewater collected and discharged 

directly. 

 As proposed, all in-scope new source dischargers had the same airfield pavement deicing 

requirements as existing sources and were required to collect 60 percent of available ADF and 

meet the specified numeric limit for direct discharges of the collected fluid. EPA estimated that 

the proposed rule would apply to 218 existing airports: 110 airports for both the pavement deicer 

and ADF collection and discharge requirements, and another 108 airports for the pavement 

deicer requirement only. Of those 218 airports, the Agency estimated that 148 airports were 

already in compliance with the proposed requirements. 

1. ADF Collection 

 The proposed rule would have required all existing primary airports that have 10,000 or 

more annual departures to collect at least 20 percent of available ADF. The 20 percent collection 

requirement was based on the estimated performance of glycol collection vehicles (GCVs). A 

subset of this group, those primary airports that use 460,000 or more gallons of normalized ADF 

annually, would be required to collect at least 60 percent of all available ADF. (As defined at 

proposed §449.2, normalized ADF is ADF less any water added by the manufacturer or customer 

before ADF application.) This collection requirement was based on the estimated performance 

of centralized deicing pads (CDPs). In-scope primary airports with less than 10,000 annual 
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departures would not be required to collect their available deicing fluid or meet associated 

discharge limitations and would have continued to be subject to BPJ permitting requirements. 

2. Numeric Limit for Collected ADF 

 For airports discharging collected ADF directly to surface waters, the proposal would 

have required them to meet numeric effluent limitations for chemical oxygen demand (COD). 

The limits were based on anaerobic fluidized bed (AFB) treatment technology. 

3. Airfield Pavement Deicers 

 EPA proposed BAT for direct dischargers associated with airfield pavement deicing 

based on product substitution. Specifically, EPA based BAT on discontinuing use of pavement 

deicers containing urea in favor of alternative, less toxic products that are also effective and not 

harmful to aircraft. 

4. Other Technology Basis Considered 

 In the proposed rule, in addition to centralized deicing pads and glycol collection 

vehicles, EPA described plug-and-pump technology with GCVs as a possible BAT basis for an 

ADF collection requirement, and calculated the cost of this technology. This technology, when 

used in combination with GCVs, is estimated to collect at least 40 percent of available ADF. 

IV. Summary of Significant Comments and Changes to Rule Since Proposal 

A. ADF Collection Requirements and Applicability 

 For BAT, EPA has revised the basis for and the applicability of the ADF collection and 

discharge requirement. As explained in Section VII.E of the proposed rule, EPA proposed as its 

lead option a combination of three different collection/discharge requirements for in-scope 

airports: 
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 Airports with less than 10,000 annual departures were not required to collect their spent 

deicing fluid or meet associated discharge limitations, but were subject to BPJ permit 

requirements; 

 Airports with 10,000 or more annual departures that use less than 460,000 gallons of 

normalized ADF per deicing season were required to collect 20 percent of available ADF 

based on GCVs and, if discharged directly, meet associated numerical discharge 

limitations based on biological treatment. 

 Airports with 10,000 or more annual departures that use 460,000 or more gallons of 

normalized ADF per deicing season were required to collect 60 percent of available ADF 

based on CDPs and, if discharged directly, meet associated numerical discharge 

limitations based on biological treatment. 

 The proposal also discussed collection and treatment of 40 percent of the available ADF, 

based on plug and pump collection technology together with use of GCVs. EPA had rejected 

this collection technology because it estimated the costs to be comparable to those of CDPs, 

while CDPs achieve greater ADF collection. 

1. Applicability of ADF Collection/Discharge Requirement for Existing Sources 

 Commenters raised multiple concerns with EPA’s proposed approach. First, commenters 

stated that annual aircraft departures are not a good proxy for ADF usage. For example, they 

explained that an airport in the very southern portion of the US could have significant departures 

but use little ADF. Second, commenters requested that EPA consider a de minimis cut-off to 

account for defrosting. Under the proposal, defrosting would be counted towards the volume of 

ADF required to be collected, yet commenters claim that it evaporates and is unable to be 

collected. Finally, airports with low overall ADF usage also requested EPA consider a de 
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minimis cut-off. They cited concerns that the costs of the collection and treatment for ADF at 

these airports are disproportionally high in relation to the amount of pollutants generated. For 

example, one commenter, a non-hub primary airport, explained that it typically receives little 

snow and conducts occasional defrosting of aircraft, and generates no ADF-contaminated water 

yet it would effectively be required to purchase a GCV if subject to the 20 percent collection 

requirement. 

 EPA reviewed its data with respect to each of these comments. On further review of the 

data and comments, we now conclude that ADF usage in general is not closely related to the 

number of departures at airports alone. As such, in today’s final rule, EPA did not base the ADF 

collection and associated discharge requirements on the number of departures. Instead, we 

decided to base the applicability of these requirements directly on estimates of the overall 

volume of ADF usage, which EPA indicated in the proposal was another possible threshold 

criterion for the rule (74 FR 44714). EPA reviewed its estimated costs for all the ADF collection 

and treatment scenarios evaluated for proposal, as a function of ADF usage and found that costs 

and impacts for airports using less than 60,000 gallons of normalized ADF annually were 

disproportionally higher than those with greater ADF usage. See DCN XXXX for additional 

details. As a result, in today’s final rule, EPA has established a cut-off of greater than or equal to 

60,000 gallons of normalized ADF per deicing season. Those airports below this threshold are 

not subject to the final rule’s ADF collection/discharge requirements, while those at or above this 

threshold are subject to these requirements. For the airports that are below this threshold, permit 

authorities will determine the technology-based limitations for aircraft deicing discharges in their 

NPDES permits on a case-by-case, best professional judgment basis. 
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2. Collection Requirement 

 Commenters also raised multiple concerns about the technology that EPA proposed to 

identify as BAT for the 60 percent collection requirement: centralized deicing pads. First, they 

raised concerns that CDPs are not feasible at all locations because of lack of space. Some of 

these commenters provided detailed engineering plans and analyses demonstrating their specific 

space constraints. Second, commenters raised concerns that using CDPs for all deicing 

operations would cause traffic and/or safety problems. Third, commenters asserted that the use 

of CDPs would lead to flight delays and that EPA had not included costs associated with such 

delays in its analyses. In addition, FAA indicated that it had similar concerns to those raised by 

industry commenters, regarding identification of centralized deicing facilities as BAT. FAA 

indicated that the 60 percent collection requirement based on the exclusive use of CDPs might 

adversely affect the operational efficiency of some of the nation's largest and busiest airports. 

Further, FAA was concerned that for those land-constrained airports, construction and operation 

of centralized deicing pads for all deicing operations would not be able to meet FAA design 

standards. In explaining its concerns, FAA noted that delays associated with the use of CDPs 

would be extremely costly to the nation's productivity, economy, businesses, and the traveling 

public. 

 After considering these comments and reviewing the information in its record, EPA is not 

promulgating 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 
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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 in order 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 ensure efficient 

operations at airports. 

 Second, based on public comments and information from FAA since proposal, 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 which, 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 a CDP, conforming 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) cannot be constructed. 

 Therefore, for today’s final rule, EPA has rejected a 60 percent ADF collection 

requirement based on identification of centralized deicing facilities as BAT for 100 percent of 
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aircraft departures because the technology is not available at most airports and, therefore not 

technologically feasible. Because EPA has rejected a 60 percent requirement in this final rule on 

the grounds that it is not technologically feasible, EPA did not do a detailed analysis of the 

commenters’ claims that significantly increased economic costs associated with flight delays 

would be expected to occur under a 60 percent collection requirement. 

B. New Source Definition and ADF Collection Requirement Applicability 

 In the proposed rule, “new source” would have included both new airports and new 

runways constructed at existing airports. Commenters objected to the inclusion of new runways 

at existing airports in the new source definition. They noted that a new runway is not a source of 

pollutant discharges from aircraft deicing activity and that a new runway is not “substantially 

independent” of an existing source as required under the regulatory definition of “new source.” 

See 40 CFR 122.2 and 40 CFR 122.29(b)(1). Commenters acknowledge that a new runway may 

lead to additional discharges associated with airfield deicing, but noted that the requirements for 

airfield deicing discharges are the same for new and existing discharges. With respect to the 

requirements associated with discharges from aircraft deicing, they explained that a new runway 

is not a source of new discharges because aircraft deicing is performed at locations away from 

airport runways. Moreover, they explained that unlike a plant or factory from which a new 

source of discharge associated with a new process, production line, or piece of equipment can be 

clearly distinguished as a new source of discharge associated with an existing source, a new 

runway is not operated independently from other runways at an airport. Rather, a new runway 

and associated deicing operations are part of a wholly integrated airport system. In light of this 

new information, EPA agrees that under the current new source definition, new runways should 
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not be treated as new sources because new runways are generally too integral to the operations of 

an existing airport to be considered “substantially independent” of the existing airport. 

 EPA has also revised the cut-off level of ADF usage that determines which new sources 

are subject to the ADF collection and discharge requirements. The proposal would have required 

ADF collection and associated discharge requirements for any new source with more than 10,000 

annual jet departures. As was the case with existing sources, commenters explained that the 

number of departures is not a good analog for the amount of ADF usage, citing, for example, 

airports in the south that may have significant numbers of departures but typically need to deice 

their aircraft only once a year. After reviewing these comments and the information in its record, 

EPA agrees that departures alone are not the most appropriate indicator of ADF usage. As 

detailed in Section IV.A.2, for existing sources, today’s final rule establishes a cut-off of greater 

than or equal to 60,000 gallons of normalized ADF per deicing season for the ADF collection 

and discharge requirements. Unlike existing sources, however, new sources do not have ADF 

usage data available—i.e., EPA cannot use past ADF usage to similarly inform a cut-off level for 

whether a new source is subject to NSPS requirements. Rather, in today’s final rule, as an 

indicator of the amount of ADF usage, EPA is basing NSPS applicability on whether the airport 

is located within specific colder climatic zones (called here “heating degree day category”) as 

documented by the National Oceanic and Atmospheric Administration (NOAA). 

A “heating degree day” means the number of degrees per day the daily average 

temperature is below 65 degrees Fahrenheit. The daily average temperature is the mean of the 

maximum and minimum temperature for a 24-hour period. The annual heating degree day value 

is derived by summing the daily heating degree days over a calendar year period. Heating 

degree days (HDD) are computed using data from the “U.S. National 1961-1990 Climate 
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Normals,” published by the National Climatic Data Center of NOAA. The original data are in 

whole degrees Fahrenheit. HDD values range from 0 to over 9,000. NOAA presents this 

information in 1,000-HDD increment groups. EPA used the NOAA information to create HDD 

groups. These groups range from A to I, with group A being the lowest HDD values (less than 

1,000 HDD) and group I being the highest (greater than 9,000 HDD). 

 EPA identified the corresponding HDD group for existing airports and then compared the 

HDD group to ADF usage at each airport. In general, airports in HDD groups A through C 

(3,000 HDD or less) used less than 60,000 gallons of ADF while those in HDD groups D 

through I used more than 60,000 gallons of ADF. As a result, these HDD groups provide a 

geographic dividing line nationwide that corresponds well with the ADF usage dividing line for 

existing airports. EPA concludes that this approach best captures those new airports which will 

conduct more frequent deicing operations and excludes those new airports that expect to conduct 

infrequent deicing. See DCN XXX for EPA’s analysis of HDD categories. 

 For the airports in the warmer climate locations that are excluded from the NSPS 

requirements in today’s final rule, permit writers would determine an applicable new source 

performance standard on a case-by-case, best professional judgment basis. 

C. Extension of Applicability Date 

 The applicability date of the final rule is 30 days following its publication in the Federal 

Register. However, the ADF collection and discharge requirements for existing dischargers are 

applicable three years following publication. See 40 CFR 449.1(b). EPA included this provision 

because it agrees with comments explaining that airports are public entities that need 

considerable time to arrange both financing and construction for capital improvements to a 

facility associated with ADF collection and treatment. Furthermore, to the extent that airports 
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can obtain financing from FAA, FAA explained that its process to obtain such funds would 

similarly require additional time. 

 The extension of time for existing airports is necessary and appropriate because EPA has 

determined that the “best available technology” identified in this rulemaking for the ADF 

collection and discharge requirements, in many cases, will not be an “available” technology upon 

the effective date of this rule (which is 30 days following publication). This is because many 

airport authorities need substantial additional time to carry out the steps for financing and capital 

improvements to implement these BAT technologies. However, the final rule provides that this 

extension of time is available only for the first three years after this rule’s promulgation. 

Existing airports that will be undergoing permit renewal past that date are able to use these first 

three years to plan and obtain financing such that the BAT technology identified in this rule will 

be “available” to them at the time of their permit renewals. Because the technology basis for the 

airfield deicing discharges (product substitution) does not require large capital expenditures, it is 

available upon the effective date of the rule and an extension of time is not similarly appropriate. 

 Because EPA has defined “new source” in today’s final rule to include only new airports, 

EPA does not believe that new sources will require an extension of time as there are no new 

airport projects planned in the near future that would be subject to the ADF collection 

requirements in this final rule. EPA consulted with FAA about the potential for construction of 

new airports over the next several years. FAA stated that there are currently no plans for new 

airports to begin construction in the next several years. As a result, EPA concludes that any 

potential new airport will have adequate time in its planning process to incorporate today’s NSPS 

requirements, and as such would not require an extension in order to comply with any of the 

requirements of today’s rule. The technology that EPA has identified in this rule as “best 
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available demonstrated control technology” for new sources will be “available” for any and all 

new airports without the need for an extension of time.

D. Deicing for Safe Taxiing 

 The proposed rule included a provision that would have exempted ADF-contaminated 

wastewater associated with deicing for safe taxiing from the proposed collection and treatment 

requirement. EPA proposed to limit deicing for safe taxiing to 25 gallons of ADF, based on an 

allowance at Denver International Airport (DIA), as the maximum amount that could be applied 

to an aircraft for the purposes of safe taxiing. This definition was intended to apply to airports 

with CDPs, and to prohibit conducting complete deicing of an aircraft at a terminal area without 

a collection system, instead of using the deicing pad. However, commenters expressed concern 

that climatic conditions at airports in the Midwest, Alaska and on the East Coast differ greatly 

from those at DIA: they claim that any “deicing for safe taxiing” allowances established at DIA 

cannot form a reasonable basis for application to airports in other regions of the country. In 

addition, cargo aircraft sometimes experience layovers in excess of 24 hours, potentially 

increasing the amount of snow or ice that must be removed to achieve compliance with FAA 

regulations. EPA agrees with the commenters and as such, the final rule does not limit the 

amount of ADF sprayed for the purposes of safe taxiing nor does the final rule require an airport 

to collect and treat ADF applied for safe taxiing purposes. 

E. Glycol Collection Vehicles 

 Although glycol collection vehicles are currently used by at least 53 airports, commenters 

suggested that requiring some airports to use GCVs could affect operations and safety at those 

facilities. Commenters’ specific concerns about the increase in GCVs at and around the gate 

areas include affecting the ability of other ground support vehicles (baggage carts, fueling trucks, 
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etc.) to perform their duties and limiting the ability of aircraft to safely maneuver at the gates. 

However, the commenters provided no data to support these claims. Currently, many airports 

use GCVs with no apparent problems. Moreover, EPA observed GCV operations during its 

airport site visits and interviewed airport personnel about operational practices and no one raised 

any safety or operational issues associated with use of GCVs. EPA also consulted with FAA 

about potential operational and safety issues of today’s regulation, and FAA raised no concerns 

about EPA’s identification of GCVs as part of the best available technology for use by airports. 

Therefore, EPA believes that the use of GCVs will not affect operations or safety of an aircraft or 

aircraft-related operations in gate areas. 

F. Effluent Limitation for Chemical Oxygen Demand 

 EPA received comments questioning the Agency’s use of chemical oxygen demand 

(COD) as an effluent limitation parameter. Specific comments include questions on whether 

EPA’s rationale for using COD as opposed to BOD5 as an indicator pollutant for glycol was 

reasonable, and whether the agency intended to set a limit for COD or soluble COD. 

1. COD as an Indicator for ADF 

 Some commenters raised issues on EPA’s selection of COD instead of BOD5 as an 

indicator parameter. Others, such as the Philadelphia Airport, agreed with EPA’s selection. 

Specific comments against EPA’s selection include: EPA’s rationale of why COD is a better 

indicator parameter is not accurate, COD does not adequately reflect the dissolved oxygen 

available for treatment in a biological treatment system, and there is an implied Congressional 

mandate to address BOD5. Each of these is discussed in more detail below. 

 EPA presented four reasons in the proposed rule as to why it selected COD as the 

indicator pollutant for ADF discharges: 
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 While both BOD5 and COD parameters are good indicators of the glycol-based oxygen 

demand component of deicing stormwater, COD will also capture the oxygen demand 

from nitrogen and other organic components of the stormwater that may not be 

represented in a BOD5 result. 

 COD analyses are simple to conduct and can be measured in real time, compared to the 

5-day test required by the BOD5 analytical method. 

 COD eliminates the need to consider receiving water temperature when evaluating water 

quality concerns. 

 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. 

 Trade association comments in response argued that EPA had not proven that COD will 

also capture the oxygen demand from nitrogen and other organic components of the stormwater. 

Furthermore, they argue nitrogen is not associated with ADF and is being regulated separately as 

part of the airfield deicing stormwater requirements. EPA agrees that nitrogen is not associated 

with ADF discharges and that it is addressing nitrogen concerns associated with airfield deicing 

discharges (specifically the generation of ammonia from urea degradation) primarily through 

regulation of ammonia as N. As such, the primary purpose of the COD indicator pollutant is to 

address organic components of aircraft deicing discharges, some of which are not captured with 

a BOD5 analysis. 

 It is widely accepted that COD measures pollutants that are not measured by BOD5. The 

ratio of COD to BOD5 for most industrial wastewater typically ranges from 1.5 to 2.0. As 

explained in Section xx of the TDD, EPA does not have information on all of the exact 
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constituents in aircraft deicing fluid. Without these data, it is not possible for EPA to determine 

the chemicals measured by COD that would not be captured by a BOD5 analysis. However, 

samples of ADF-contaminated wastewater show a similar trend to typical industrial wastewater 

(i.e., COD concentrations are higher than BOD5 concentrations), indicating that ADF has 

oxygen-demanding additives that are not measured by a BOD5 analysis. Therefore EPA has 

determined that the most robust and accurate manner of documenting the oxygen demand 

associated with ADF is to use the more inclusive oxygen demand indicator, COD. 

 Commenters also argued that COD measurement in “real time” versus the five days 

required for the BOD5 test was not a valid reason for selection of COD as the regulated pollutant. 

EPA disagrees and concludes that this is a highly significant reason for selecting COD as the 

appropriate pollutant for regulation. Because COD can be measured more quickly and 

accurately, it allows a treatment operator more ability to ensure optimal and reliable operation 

than the BOD5 test would allow. Data provided by the industry and a manufacturer of an AFB 

system demonstrate that it is industry practice to evaluate treatment effectiveness and system 

control by measuring the COD of the system effluent. Specifically, the record demonstrates that 

industry uses COD because the BOD5 analyses requires five days to obtain a result and does not 

enable a system operator to obtain invaluable feedback to evaluate treatment system control and 

effectiveness in real time allowing for optimal treatment system operation. (The use of COD in 

place of BOD5 is also used to optimize and evaluate biological treatment of other industrial 

wastewaters and is widely recommended in wastewater treatment references.) 

Real-time feedback through use of the COD parameter is particularly important for 

optimal treatment and control of ADF wastewaters in this rulemaking, compared to other effluent 

limitation guidelines. Most ELGs for other industrial categories with BOD5 limitations limit 
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individual constituents in addition to BOD5. In such cases, most facilities have on site 

laboratories that provide the capability to measure those constituents in real time. As a result, 

treatment operators use the data from the individual constituents to monitor and adjust the 

operation of their treatment system in real time to ensure optimal treatment. In contrast, in 

today’s final regulations for ADF, there are no limits being set for individual constituents in the 

waste stream. Consequently, there will be no data from monitoring of individual constituents on 

which to base real-time adjustments to the treatment system. Instead, to make such real-time 

adjustments, under today’s rule, operators will be able to rely on COD measurements. 

 In addition, EPA notes that the commenters’ remarks concerning consideration of 

receiving water temperature when evaluating water quality concerns using a BOD5 value vs. 

COD are irrelevant. EPA agrees that organic compounds like glycol might degrade at a slower 

rate in cold receiving waters; however, effluent limits are not established based on receiving 

water temperature, but on treatment system performance. For example, secondary treatment 

effluent limitations for BOD5 from publicly owned treatment works are established on treatment 

system performance, and compliance with the BOD5 limitation requires the POTW to measure 

BOD5 using an approved analytical method. That method requires sample analysis be conducted 

at 20o C, regardless of the receiving water temperature. Therefore establishing an effluent 

limitation based on COD or BOD5 is appropriate for the airport deicing rule because receiving 

water temperature is not a factor in analytical methods used to determine compliance.

 Finally, commenters argued that use of BOD5 instead of COD is appropriate because any 

effect of toxicity on BOD testing can be accounted for through proper analysis. EPA disagrees 

that the BOD5 and COD tests are equally appropriate in this regard. In evaluating pollutants of 

concern for aircraft deicing-related stormwater, EPA noted that there are additives to ADF, 
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which may exert toxicity above that caused by the oxygen demand of the glycol components of 

these fluids. Until the effects of these additive compounds are further understood, EPA 

maintains that their presence in deicing stormwater (which was confirmed through EPA’s 

sampling efforts) may cause negative and variable affects on the acclimation of the active 

cultures used in BOD analysis. This issue is not a factor for COD analysis. 

2. Arguments that EPA Must Address BOD5 

 Commenters argued that EPA impermissibly selected COD as the regulated pollutant and 

should have selected BOD instead. As asserted by one commenter, by designating COD (a 

nonconventional pollutant) as the “regulated pollutant,” and then developing a proposal only at 

the BAT level, EPA has avoided the need to characterize the levels of treatment that would be 

needed if EPA were regulating BOD5, which is a conventional pollutant – i.e., EPA has avoided 

the cost tests applicable to BPT and the two-part cost sensitivity analysis that is required for a 

BCT analysis. It believes that EPA’s decision that COD is the appropriate regulated pollutant 

rather than BOD5, “facilitates the imposition of BAT, which is potentially much more stringent 

and costly than BPT or BCT.” (DCN xxx [ATA, Docket #1226], p. 167) 

 In response, EPA has discretion to determine what pollutant parameters are appropriate to 

regulate as pollutants of concern in an effluent guideline. See, e.g., National Wildlife Federation 

v. EPA, 286 F.3d 554 (D.C. Cir. 2002) (EPA had discretion not to regulate color as a pollutant of 

concern). Chemical oxygen demand is a pollutant in and of itself. See BASF Wyandotte Corp. 

v. Costle, 598 F.2d 637, 651 (1st Cir. 1979). The CWA defines pollutant broadly to include 

“dredged spoil, solid waste, incinerator residue, sewage, garbage, sewage sludge, munitions, 

chemical wastes, biological materials, heat, wrecked or discarded equipment, rock, sand, cellar 

dirt and industrial, municipal and agricultural waste” (CWA section 502(6)). See NRDC v. EPA, 
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822 F.2d 104, 109 (D.C. Cir. 1987)(“The term ‘pollutant’ is broadly defined . . .”); U.S. v. 

Hammel, 551 F.2d 107, 110 (6th Cir. 1977)(noting that the definition is set forth in “broad 

generic terms”). COD is a chemical measure of the oxygen requirement to oxidize the organic 

matter in water. COD, like BOD or pH, which are expressly mentioned as conventional 

pollutants in CWA section 304(a)(4) and 40 CFR 401.16, easily fits that definition. The 

definition of pollutant is not limited to those terms that are specifically listed in the statute at 

section 502(6). See NWF v. Gorsuch, 693 F.3d 156, 174 n. 56 (D.C. Cir. 1982); Sierra Club v. 

Cedar Point Oil Co., 73 F.3d 546, 565 (5th Cir. 1996). Thus, COD is a pollutant under the Act, 

and EPA has described above the comprehensive reasons for why it determined that COD is the 

appropriate pollutant on which to set effluent limitations in this rule rather than BOD5. 

An additional reason why it is appropriate to set limits in this rule based on COD is that, 

apart from the biodegradable oxygen-demanding organic containing pollutants, the wastestream 

from aircraft deicing operations also contains certain non-conventional pollutants that may not be 

measured in a BOD5 analysis. Even if EPA were to set BPT/BCT limits for the oxygendemanding pollutants on the basis of BOD5, we would still be required to promulgate the BAT 

limits in this final rule in order to control the non-conventional pollutants that may not be 

measured by the BOD5 analysis. Any BPT/BCT established for BOD5 would be equal to or less 

stringent than the BAT limits that would be set for these other non-conventionals. Because the 

BAT limits would be controlling, any additional BPT/BCT limits established for BOD5 would 

therefore be superfluous. 

Aircraft deicing fluid contains not only biodegradable oxygen-demanding pollutants but 

also chemical additives which, under the CWA, are toxic or non-conventional pollutants. 

Additionally, stormwater discharges from airports in their entirety are “industrial waste,” a 
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nonconventional pollutant under the CWA (see, e.g., Reynolds v. Rick's Mushroom Service, 

Inc., 246 F.Supp.2d 449, 455 (E.D. Pa. 2003) (rainwater contaminated by industrial waste 

constitutes a pollutant). EPA is not required to single out specific constituents or parameters in 

the discharge. See Northern Plains Resource Council v. Fidelity Exploration and Development 

Co. 325 F.3d 1155 (9th Cir. 2003). The appropriate level of control under the CWA for these 

nonconventional pollutants is BAT. See CWA section 301(b)(2)(A) and (F). Similarly, the 

appropriate level of control under the CWA for all pollutants from new sources is best available 

demonstrated control technology (BADCT). See CWA section 306. 

Where the same wastestream contains both conventional pollutants (such as BOD5) and 

toxic and non-conventional pollutants, it is reasonable to limit the rule to BAT limits (and 

BADCT standards for new sources) because these controls would supersede any less stringent 

limits under BPT or BCT. The first component of the BAT technology in this final rule is a 

collection requirement, requiring in-scope airports to collect 40 percent of available ADF after it 

is applied to aircraft. Even if the oxygen-demanding pollutant in ADF were considered to be a 

conventional pollutant (BOD5), the ADF contaminated stormwater that is collected contains 

other non-conventional pollutants, as described above. The final rule thus would contain, under 

any scenario, a BAT requirement of 40 percent collection to control these other nonconventionals. This 40 percent collection requirement would be controlling even if EPA were to 

determine that the criteria for BPT/BCT would result in a less stringent collection requirement 

for conventional pollutants in the discharge. Collection is done once, and obviously will capture 

whatever pollutants are in the discharge; it is not possible to have different collection 

requirements for different pollutants in the discharge. 
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The second component of BAT identified in this final rule is based on treatment of the 

collected ADF contaminated stormwater by an anaerobic fluidized bed treatment system. Again, 

based on the presence of the non-conventional pollutants alone, the final rule would require 

treatment of all the collected ADF through an AFB treatment system. Doing so would treat any 

conventional pollutants such as BOD5 in the wastestream as well. In sum, both the collection 

and treatment components of BAT in today’s rule will apply to the entire wastestream, based on 

the non-conventional pollutants in the wastestream alone. Those collection and treatment 

requirements would be controlling even if there were other conventional pollutants contained in 

the wastestream as well, such as BOD5. 

3. COD Versus Soluble COD as a Regulated Pollutant 

EPA proposed to establish a numeric limit for COD for direct discharges of collected 

ADF based on anaerobic fluidized bed treatment. EPA calculated the proposed COD limit from 

long term sampling data from Albany Airport. EPA received comments in support of its use of 

Albany sampling data for setting the numeric limit. However, commenters correctly noted that 

while EPA proposed to establish a COD limit, Albany filtered its sample prior to analyzing for 

soluble COD. Moreover, commenters stated that setting a COD limit based on soluble COD data 

is inappropriate because COD measurements would likely be higher than the proposed limit. 

EPA agrees with the commenters that the Albany data upon which it developed the proposed 

limit reflects COD that is filtered. As a result, today’s final rule includes a sampling protocol for 

airports to filter compliance samples prior to analysis for COD. 

 

V. Scope and Applicability of the Final Rule 
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 This final rule applies to primary airports with discharges from deicing operations. The 

applicability is further narrowed in the provisions on BAT and NSPS, to airports with greater 

than or equal to 1,000 annual departures by non-propeller-driven aircraft. The ammonia 

discharge provisions (concerning runway deicing), § 449.10(b) for BAT and § 449.11(b) for 

NSPS, apply to all such airports. In addition, existing in-scope airports that use ADF at an 

annual rate of 60,000 gallons or more (normalized) are subject to the BAT collection and 

discharge requirements, as applicable at § 449.10(b) and (c). New source airports located in an 

area with more than 3,000 annual heating degree days are subject to NSPS collection and 

discharge requirements, as applicable at § 449.11(a) and (b) (see discussion above). 

 A new airport with deicing discharges, that is initially operating less than 1,000 nonpropeller aircraft departures annually is not initially subject to the NSPS provisions in §449.11. 

However, if the number of departures later increases above that threshold, then §449.11 becomes 

applicable. This means that a new airport that expects to eventually exceed the 1,000 departure 

threshold must plan to install and operate facilities that comply with the requirements of that 

section. 

A. Subcategorization 

 EPA may divide a point source category into groupings called "subcategories" to provide 

a method for addressing variations among products, processes, and other factors, which result in 

distinctly different effluent characteristics. See Texas Oil & Gas Ass'n. v. US EPA, 161 F.3d 

923, 939-40 (5th Cir. 1998). Regulation of a category by subcategories provides that each 

subcategory has a uniform set of effluent limitations that takes into account technological 

achievability and economic impacts unique to that subcategory. In some cases, effluent 
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limitations within a subcategory may be different based on consideration of these same factors, 

which are identified in CWA section 304(b)(2)(B). The CWA requires EPA, in developing 

effluent guidelines, to consider a number of different factors, which are also relevant for 

subcategorization. The CWA also authorizes EPA to take into account other factors that the 

Agency deems appropriate. 

 In developing today’s rule, EPA considered whether subcategorizing the aviation 

industry was warranted. In addition to those factors specified in the CWA, EPA evaluated a 

number of factors and potential subcategorization approaches, including the presence of an onsite glycol reclamation facility, amount of ADF applied, number of departures, availability of 

land to install collection systems, and FAA airport classifications. EPA concluded that 

establishing formal subcategories is not necessary for the Airport Deicing category. EPA 

structured the applicability and requirements of the final rule to account for the relevant factors 

(e.g., amount of ADF applied) and has established a set of requirements appropriate for the range 

of situations that an airport may encounter during deicing operations. Commenters suggested 

there should be a separate subcategory for land-constrained airports, however now that EPA has 

determined that CDPs are not the basis for BAT, there is no longer a need for a formal 

subcategory. 

B. Industry Description 

 The Airport and Airway Improvement Act (AAIA), 49 U.S.C. Chapter 471, defines 

airports by categories of airport activities, including Commercial Service (Primary and NonPrimary), Cargo Service, and Reliever. These categories are not mutually exclusive; an airport 

may be classified in more than one of these categories. Another group of generally smaller 
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airports, not specifically defined by AAIA, is commonly known as "general aviation" airports. 

EPA estimates that there are approximately 500 commercial service airports. 

 Commercial service airports are publicly owned airports that have at least 2,500 

passenger boardings each calendar year and receive scheduled passenger service. Passenger 

boardings refer to revenue passenger boardings on an aircraft in service in air commerce, 

whether or not in scheduled 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 non-traffic 

purpose, such as refueling or aircraft maintenance rather than passenger activity. Passenger 

boardings at airports that receive scheduled passenger service are also referred to as 

"enplanements." 

 Primary commercial service airports (primary airports) have more than 10,000 passenger 

boardings each year. Primary 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 development process, EPA focused on deicing activities at 

primary airports, particularly those with extensive non-propeller traffic. Operators of general 

aviation aircraft, as well as smaller commercial non-jet aircraft, typically suspend flights during 

icing conditions, whereas commercial airlines operating at primary airports are much more likely 

to deice their jets in order to meet customer demands. 

 Based on the results of surveys of the industry that EPA conducted prior to the proposed 

rule, the Agency estimated that 320 primary airports conduct deicing operations. EPA reviewed 

the relative sizes of various airports (based on annual departures), the levels of deicing activity, 
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traffic characteristics (i.e. passenger vs. cargo operations), the extent of pollution controls and 

treatment in place, and the costs of various technologies for these airports. EPA further 

classified airports based on the number of annual non-propeller departures. EPA found that there 

were some primary airports, typically smaller airports, with high percentages of non-propeller 

aircraft, and so it excluded airports with fewer than 1,000 annual non-propeller departures from 

the scope of the proposed rule. These airports have a higher proportion of propeller-aircraft 

flights, which are typically delayed or cancelled during icing conditions (i.e. far less deicing 

takes place at these airports, and far less deicing fluid is used, than at airports serving more jets). 

C. Wastewater Sources and Wastewater Characteristics 

1. Aircraft Deicing 

 Airlines apply most ADF to aircraft through pressurized spraying systems, mounted 

either on trucks that move around an aircraft, or on large fixed boom devices located at a pad 

dedicated to deicing. 

 Most of the aircraft deicing fluid sprayed is Type I fluid, which is designed for minimal 

adhesion to aircraft surfaces. Consequently the majority of Type I ADF is available for 

discharge due to dripping, over-spraying, tires rolling through or sprayed with fluid, and shearing 

during takeoff. Once the ADF has reached the ground, it will then mix with precipitation, as 

well as other chemicals found on airport surfaces. (These chemicals typically include aircraft 

fuel, lubricants and solvents, and metals from aircraft, ground support and utility vehicles.) 

Water containing these substances enters an airport's storm drain system. At many airports, the 

storm drains discharge directly to waters of the United States with no treatment. 
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Type IV fluid, an anti-icing chemical, is designed to adhere to the aircraft. Because of 

this adherence characteristic, EPA estimated that the majority of Type IV fluid is not available 

for collection. 

For the purposes of this rule, the pollutant loadings are discussed in terms of applied ADF 

and how much of that is expected to be discharged. A more detailed discussion of loadings 

estimates is presented in Section VII.B below. Given the highly variable nature of storm events, 

it is difficult to estimate flows or concentrations of ADF-contaminated stormwater generated at 

an airport. Those factors are greatly dependent on site specific factors such as the size of the 

storm event associated with the discharge, drainage characteristics, ADF collection systems (if 

present), and airport operations. Additionally, due to the design of drainage systems at some 

airports, their discharges may occur well after a storm event has completed. 

2. Airfield Pavement Deicing 

 Most solid airfield deicing chemical products are composed of an active deicing 

ingredient (e.g., potassium acetate, sodium acetate) and a small amount of additives (e.g., 

corrosion inhibitors). Liquid airfield deicing chemical products are composed of an active 

ingredient (e.g., potassium acetate, propylene glycol), water, and minimal additives. The airfield 

deicing products that include salts (i.e., potassium acetate, sodium acetate, and sodium formate) 

will all ionize in water, creating positive salt ions (K+

, Na+), BOD5 and COD load as the acetate 

or formate ion degrades into carbon dioxide (CO2) and water. Pavement deicers containing urea 

will degrade to ammonia, and generate BOD5 and COD load as well. 

 Most of EPA’s deicing characterization data does not reflect airfield pavement deicers. 

However, EPA collected samples from a few locations at Detroit Metro Airport that contain 

airfield deicing stormwater. Large hub airports, both Detroit Metro and Pittsburgh, provided 
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sampling data associated with stormwater contaminated by airfield pavement deicers. More 

information on these sampling activities is provided in the TDD. As with the aircraft deicers, the 

variability of storm events and drainage systems makes it difficult to estimate flows or 

concentrations of pavement deicing waste streams generated at an airport. 

D. Control and Treatment Technologies for the Aviation Industry 

 The ADF application process has presented a challenge for airports attempting to manage 

their contaminated stormwater streams. The process of applying ADF to aircraft through high 

pressure spraying, combined with the typical practices of spraying the aircraft outdoors in 

multiple, large unconfined (but usually designated) spaces, results in pollutants being dispersed 

over a wide area and entering storm drains at multiple locations. This process contrasts sharply 

with many other industries where pollutants are generated in confined areas, managed through a 

piping system, and not commingled with precipitation. 

 EPA has identified several technologies that are available to collect and manage portions 

of the ADF wastestream. Some of these collection technologies are more effective than others. 

However, no single technology is capable of collecting all applied ADF, as a portion of the fluid 

is designed to adhere to the aircraft until after takeoff, to ensure safe operations. Furthermore, 

with few exceptions, tracking by aircraft tires, wind dispersion, and dripping during taxiing and 

takeoff ensures that some amount of sprayed ADF, even if performed in a contained area, will 

end up in the drainage system of the airport. For these reasons EPA concludes that all airports 

that perform aircraft deicing operations are direct dischargers. (There are limited instances 

where an airport in a warm climate that performs only defrosting and gets little to no 

precipitation may, in fact, not discharge any deicing materials.) 
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 Once the available ADF wastestream is collected, it can be treated, and this process is 

similar to many other industries that generate wastewater. In a similar manner, airfield deicing 

has presented a challenge for airports attempting to manage their contaminated stormwater 

streams. Airfield deicing is typically conducted over a large area, including areas with frequent 

aircraft traffic, such as runways, where active collection technologies (i.e. GCVs) are impractical 

to implement. At this time, EPA has not identified any available economically achievable 

technologies for the collection of pavement deicing stormwater. As a result, EPA also examined 

pollution prevention technologies, which can reduce or eliminate use of ADF chemicals and urea 

containing deicers for pavement deicing in today’s final rule. 

 The following section discusses the technologies EPA considered for ADF collection and 

treatment and for addressing airfield deicing. 

1. Aircraft Deicing Fluid Collection Technologies 

a. Glycol Collection Vehicle. 

 A glycol collection vehicle (GCV) is a truck that utilizes a vacuum mechanism to gather 

stormwater contaminated with ADF resulting from deicing operations. GCVs are typically 

stationed near the ADF spraying trucks and are deployed either during aircraft deicing activities 

or, after the aircraft deicing activity has completed. The GCV then transports the ADFcontaminated stormwater to an on-site storage and/or equalization facility, after which the 

material is either treated at the airport or sent off site for treatment. EPA estimates that GCVs 

typically collect at least 20 percent of the available ADF when properly operated and maintained. 

b. Plug and Pump 

The plug-and-pump collection system utilizes an airport’s existing storm water collection 

system infrastructure to contain and collect ADF contaminated stormwater. Plug and pump 
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systems also commonly utilize GCVs for ancillary ADF collection. Typical GCV deployment 

may include collecting ADF that has been sprayed beyond the plug and pump containment area 

or as an additional collection measure at the gate, ramp and/or apron area after deicing operations 

and active plug and pump collection has ceased. The plug and pump system operates by placing 

either temporary inflatable balloons or storm sewer shutoff valves in the existing storm sewer 

system. During deicing events, the balloons are inflated and storm sewer shutoff valves are 

closed, trapping the ADF-contaminated stormwater in the collection system. Vacuum trucks 

pump the trapped contaminated stormwater from the storm sewer system and transport the liquid 

to on-site storage and/or equalization. In addition, catch basin inserts can be placed into 

manholes to collect ADF-contaminated stormwater. 

c. Centralized Deicing Pads 

 A centralized deicing pad is a paved area on an airfield built specifically for aircraft 

deicing operations. It is typically located 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 wastewater storage facility, which 

then may send the wastewater to an on-site or off-site treatment facility. 

Some airports use GCVs in combination with CDPs to collect ADF that lands outside the 

pad collection area in order to maximize collection and containment of ADF-contaminated 

stormwater. Airports typically locate the pads near the gate areas or at the threshold of a runway 

to minimize delays in aircraft takeoff and to enhance the effectiveness of the ADF applied by 

limiting time between application and takeoff. 
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CDPs reduce the volume of deicing wastewater by restricting deicing to small areas, and 

managing the collected wastewater through a dedicated drain system. EPA estimates that CDPs 

allow airports to collect at least 60 percent of the available ADF. 

d. Summary of ADF Collection Technology Usage 

 EPA estimates the number of airports that use each of the above collection technologies 

in Table V-1. Some airports use more than one technology, and some of the airports in the 

estimate use the technology for only a portion of their ADF-contaminated stormwater. 

Table V-1. Estimated Totals of ADF Collection 

Technologies Used by Airports 

Collection Technology Number of Airports 

Glycol Collection Vehicle 53 

Plug and Pump 29 

Centralized Deicing Pad 66 

See section 8.2 of the Technical Development Document for further explanation of EPA’s 

estimates of the ADF collection rates for the fluid collection technologies. 

2. ADF-Contaminated Wastewater Treatment Technologies 

 In the proposed rule EPA identified four technologies for treating ADF-contaminated 

wastewater: Anaerobic Fluidized Bed (AFB), Ultrafiltration/Reverse Osmosis, Mechanical 

Vapor Recompression and Distillation, and Aerated Pond. The Agency selected AFB and 

rejected the other technologies. See 74 FR 44687 and the TDD. 

 An AFB treatment system uses a vertical, cylindrical tank in which the ADFcontaminated 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 on 

and coats each granular activated carbon particle, providing a vast surface area for biological 
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growth. These microorganisms provide treatment of the ADF-contaminated stormwater. 

Byproducts from the AFB treatment system include methane, carbon dioxide and new biomass 

(animal material, e.g. bacteria). The AFB treatment system includes storage as an initial step to 

equalize flows and pollutant concentrations that feed into the biological treatment unit. 

 Treating wastes using an anaerobic biological system as compared to an aerobic system 

offers several advantages. The anaerobic system requires much less energy since aeration is not 

required and the anaerobic system 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. Based on EPA sampling results, the AFB treatment system successfully removes 

over 98 percent of BOD5, over 97 percent of COD, and over 99 percent of propylene glycol from 

deicing wastestreams. This reduces the BOD5 and COD loads discharged to receiving waters by 

over 98 and 97 percent, respectively. Two airports in the United States use the AFB technology: 

Albany International Airport in Albany, New York, and Akron-Canton Regional Airport, Akron, 

Ohio. Additionally, Portland International Airport (Oregon) recently installed an AFB system 

and T.F. Green Airport (Providence, RI) is planning installation of this technology. 

 3. Pollution Prevention Technologies 

 EPA has identified several technologies that may reduce ADF usage, that are in use at 

airports across the United States. The following section describes the major pollution prevention 

approaches EPA identified during this rulemaking. However, there are limited data on the actual 

pollutant reductions that these technologies may achieve. In addition, the airports that use these 

technologies only use them on a limited basis. As a result, they are not currently demonstrated to 

be widely feasible and/or available technology and EPA did not consider them as a basis for 

BAT or NSPS in today’s final rule. If these technologies are proven to be available and 
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effective, they have the ability to eliminate or reduce ADF application. The ability to reduce the 

amount of applied deicing chemicals will not only have a positive environmental effect, but may 

also be cost-effective, as the decreases in costs of purchased deicing chemicals may offset the 

cost of the technology itself. 

 EPA applauds all efforts to develop deicing chemicals and approaches that reduce or 

eliminate pollutant discharges. In order to ensure that this rule doesn’t prevent such approaches 

as they become proven, feasible, and available, today’s final rule includes a provision to apply a 

pollution prevention credit against the standard ADF collection requirement. See Section XI.C., 

Demonstrating Compliance with the ADF Collection Requirement, in this preamble. 

a. Infrared Deicing Systems 

 A few U.S. airports have used infrared (IR) heating systems for several years and these 

systems have been demonstrated to deice aircraft effectively. One type of IR system consists of 

an open-ended hangar-type structure with IR generators mounted inside, suspended from the 

ceiling. The IR equipment is designed to use specific wavelengths that heat ice and snow, and 

minimize heating of aircraft components. The IR energy level and wavelength may be adjusted 

to suit the type of aircraft. Although the system can deice an aircraft, it cannot provide aircraft 

with anti-icing protection. Consequently, when the ambient temperature is below freezing, antiicing fluid is typically applied to the aircraft after it leaves the hangar. In addition, a small 

amount of deicing fluid may be required for deicing areas of the aircraft not reached by the IR 

radiation, such as the flap tracks and elevators. The system, therefore, does not completely 

replace glycol-based fluids, but may greatly reduce the volume required. 
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 Vendors claim use of an IR system reduces the amount of Type I ADF required by up to 

90 percent. John F. Kennedy International Airport, New York, uses an IR system for a small 

percentage of its flights. 

b. Forced Air/Hot Air Deicing Systems 

 Forced air/hot air deicing systems are currently in operation at a few U.S. airports. These 

systems use forced air to blow snow and ice from aircraft surfaces. Some systems allow deicing 

fluids to be added to the forced air stream at different flow settings (e.g., 9 and 20 gpm), while 

other systems require separate application of deicing fluid. Several vendors are currently 

developing self-contained, truck-mounted versions of these forced-air systems, and most systems 

can be retrofitted onto existing deicing trucks. 

 A similar method to truck-mounted forced-air systems is the double gantry forced-air 

spray system. The gantries support a set of high- and low-pressure nozzles, which blast the 

aircraft surfaces with heated air at a pressure of 40 to 500 pounds per square inch. When 

weather conditions are severe, a small volume of water and glycol may be added to the air stream 

to remove dense coverings of snow and ice. Airfield use of the gantry system has been limited 

perhaps because it is a permanently mounted system that has been known to cause delays in 

aircraft departures. 

c. Product Substitution 

 Another solution to environmental problems associated with deicing chemicals is to 

replace chemical deicers with more environment-friendly products. In the ADF products 

category, initially the predominant deicers were based on ethylene glycol, whereas in recent 

years propylene glycol-based deicers, which are less toxic to mammals, have become more 

widely used. Chemical manufacturers, the aviation industry and the U.S. Air Force are 
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continuing to explore development of deicers that could generate lower levels of pollutants 

compared to the glycol-based products. 

4. Airfield Pavement Deicing Control Technologies 

 EPA identified product substitution as an available control technology for airfield 

pavement deicing chemicals. The Agency did not identify an available economically achievable 

technology to collect and treat pavement deicing pollutants. 

 Several types of products are available as alternatives to pavement deicers containing 

urea, such as potassium acetate, sodium formate and sodium acetate. The results from EPA’s 

airport questionnaire reported that eighty-three percent of primary airports use airfield pavement 

deicers that do not contain urea. The most widely used substitute product, potassium acetate, 

accounts for 63 percent (by weight) of the annual airfield pavement deicer usage in the U.S. 

E. Regulated Pollutants 

 EPA identified 31 pollutants of concern that stem directly from airport deicing 

operations. In today’s rule, EPA is establishing discharge limitations for collected ADF 

contaminated stormwater for COD only and requiring product substitution (or, alternatively, 

meeting an ammonia limit) to reduce ammonia discharges associated with airfield deicing. See 

Section 6 of the Final Technical Development Document for a full discussion of pollutants of 

concern and EPA’s rationale for selecting regulated pollutants. 

VI. Final Regulation 

A. BPT and BCT 

 EPA considered whether in this rule, it was necessary to establish BPT limits, given that 

ADF and pavement deicers will be controlled at the no less stringent BAT level. Because the 

BAT controls in this rule also result in the collection and treatment of glycol at the same level as 
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would be established in BPT limits, it is not necessary for EPA to promulgate BPT effluent 

limitation guidelines for the Airport Deicing Category. Additionally, EPA is not establishing 

BCT limitations for this industry because these limitations apply only to conventional pollutants 

such as BOD5 and total suspended solids, and for the other reasons set forth in the related 

discussion above at Section IV.F, Effluent Limitation for Chemical Oxygen Demand. 

B. BAT 

 For airfield deicing (runways), EPA concludes that the “best available technology” for 

reducing ammonia in wastewater discharges consists of the use of deicing products not 

containing urea, instead of deicing products that contain urea. The record 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 economic 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. 

 In addition, with respect to aircraft deicing, for a subset of airports subject to the rule 

(with average annual normalized ADF usage as described in 40 CFR 122.21(s)(1) of 60,000 

gallons or greater as calculated over the previous five deicing seasons), the rule also requires 

ADF collection of 40 percent of available ADF and treatment of collected ADF prior to direct 

discharge to meet a numerical effluent limitation for COD. 

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 required in collecting and treating the large volumes of 
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contaminated stormwater generated on paved airfield surfaces. EPA is not aware of an available, 

economically achievable means for controlling these pollutants through collection and use of 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 as the primary pollutant of concern from 

airfield deicing, while COD from airfield deicing is also a pollutant of concern, and both of these 

pollutants are a byproduct of pavement deicers containing urea. Accordingly, to address 

discharges of ammonia from airfield pavement, EPA identified one candidate for best available 

technology, namely, product substitution, or discontinuing the use of pavement deicers 

containing urea and using alternative pavement deicers instead. EPA found that the use of 

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, it 

does not produce discharges of ammonia as are produced by deicers containing urea, and it is 

economically achievable for all airports. Currently only about 10 percent of chemical pavement 

deicers applied nationwide contain urea. The most widely used pavement deicer is potassium 

acetate, 63 percent of all chemical pavement deicers, and is used nationwide. 

 Under the final rule, this requirement is implemented through one of two ways: (1) any 

discharger subject to this part must certify annually that it does not use airfield deicing products 

that contain urea, or (2) airfield pavement discharges at all locations where pavement deicers 

contain urea must achieve the numeric limitation of 14.7 mg/L for ammonia prior to any dilution 

or commingling with non-deicing stormwater. 

 This numeric limit is based on the ammonia generated by the BAT technology for 

treating aircraft deicing wastewater. EPA expects that most dischargers will select a certification 
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route to comply with this limit. However, if airports choose not to so certify, EPA is providing a 

numeric limitation as an alternative compliance mechanism. EPA chose to use the ammonia 

levels discharged from the AFB treatment system as the basis for setting the numeric limit to 

ensure that no inadvertent exceedances of the limit occur from ammonia generated by the AFB 

treatment system, in cases where the effluent from AFB treatment is discharged through the 

same outfalls as are used for discharges from runways. Information in the record for today's rule 

indicates that discharges from airports not using pavement deicers containing urea are well 

below the promulgated numeric limit for ammonia. Airports provided data to EPA on outfall 

concentrations of ammonia associated with pavements treated with deicers not containing urea. 

These concentrations are below the promulgated numeric limit for ammonia. 

 While EPA is unaware of a method to collect and treat all pavement deicer containing 

stormwater, some industry commenters stated, but provided no data to support, that deicers 

containing urea are more effective at than non-urea deicers at lower temperatures. The record 

contains some evidence to the contrary. Nevertheless, the final rule is crafted such that an airport 

is able to use a deicer containing urea in the event it is able to collect and treat the airfield 

discharges to meet the numeric ammonia limit. 

2. Aircraft Deicing: ADF Collection Requirements and Effluent Limitations 

a. Available ADF Collection Technologies and Scope 

 Another primary component of today’s rule concerns deicing fluid that is applied to 

(sprayed onto) aircraft. For the reasons explained in Section IV.A, EPA based the applicability 

of final ADF collection and discharge requirements on ADF usage and established a small ADF 

usage cut-off below which these requirements do not apply. (Permit authorities will determine 

the technology-based limitations for small ADF discharges on a case-by-case, best professional 
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judgment basis.) This final rule requires the collection of available ADF at airports that use 

greater than or equal to 60,000 gallons of normalized ADF per deicing season and establishes 

requirements for direct discharges of collected ADF. EPA estimates that 55 airports are subject 

to this requirement. EPA is not aware of an available and economically achievable technology 

that is capable of capturing 100 percent of the sprayed ADF. Section V.D.1 details the available 

technologies for collecting ADF: glycol collection vehicles, plug-and-pump equipment, and 

centralized deicing pads. EPA estimates these technologies collect 20 percent, 40 percent and 60 

percent of available ADF, respectively. Section IV.A.2 explains that EPA no longer considers 

CDPs as representative of BAT. The Agency then considered the other technology options 

described in the proposal--those with ADF collection requirements of 40 and 20 percent. 

 b. Options Considered for BAT for Today’s Final Regulation 

 EPA considered two options for today’s final rule: 

 Option 1: 40 percent ADF collection requirement for the large ADF users (based on plug 

and pump with GCVs) and 20 percent ADF collection requirement for medium ADF 

users (based on GCVs); and 

 Option 2: 40 percent ADF collection requirement for large and medium ADF users 

(based on plug and pump with GCVs). 

Both options include the following: 

 Airports with normalized ADF usage below 60,000 gallons/year are not subject to the 

ADF collection requirement in this rule (they would receive case-by-case effluent 

limitations in their permits for their aircraft deicing discharges). 

 For deicing of aircraft, numeric COD limitations for direct discharges of collected ADF 

(based on anaerobic treatment). 
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 For deicing of airfield pavement, BAT is identified as the use of only deicers that do not 

contain urea, implemented through either a certification that only non-urea airfield 

pavement deicers are used or meeting a numeric effluent limitation for ammonia (as total 

nitrogen), based on product substitution. 

The technology basis for the numeric COD limitations in the final rule is Anaerobic Fluidized 

Beds (AFB), as described in Section V.D.2. The identification of AFB as best available 

technology for control of COD and the numeric limitations that AFB can achieve is unchanged 

from proposal (74 FR 44692). The technology is technologically feasible and available for all 

airports. 

 Under the first option, 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 be required to collect 40 percent of available 

ADF based on the usage of plug and pump with GCV technology. 

 Under the second option, 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 and 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 achieved greater ADF collection. In the proposal, EPA therefore identified centralized 

deicing pads as BAT. Because EPA no longer considers centralized deicing pads a BAT 

candidate technology, the plug and pump with GCV option represents the technology, among 
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those that are widely available, that would achieve the greatest collection of ADF considered for 

today’s final rule. 

 Under both options, the requirement to meet numeric effluent limits for COD for the 

collected ADF would need to be met prior to commingling with other wastestreams prior to 

discharge. For a discussion of other technologies examined and rejected as candidates for the 

basis of the COD limitations, see Section VII.E.2 in the proposed rule preamble (74 FR 44692) 

and Section 7 of the TDD. 

3. BAT Options Selection 

 EPA concludes that both Option 1 and Option 2 are technologically feasible and available 

to all airports. Option 1 would remove 30 million pounds of ammonia and COD with a projected 

annual cost of $49million while option 2 would remove 33 million pounds of ammonia and COD 

with a projected cost of $78 million. Further, as discussed in more detail in Section VIII, EPA 

finds both options are economically achievable. In addition, EPA examined the non-water 

quality impacts anticipated from compliance with today’s final rule and found that they were 

very minor in comparison to typical industry energy use, emissions generation and sludge 

generation. See Section X, “Non Water Quality Environmental Impacts.” The main difference 

between the two options is the pollutant reduction and projected compliance costs. Option 2 

achieves greater pollutant reductions with greater costs compared to Option 1. Moreover, in 

comparing the costs to achieve reductions under either option, both options produce costs that 

are reasonable in terms of the pollutant reductions achieved ($1.64/lb and $2.37/lb for Options 1 

and 2, respectively). Therefore, based on all the factors above and that Option 2 achieves the 

greatest amount of pollutant reduction, EPA is identifying Option 2 as BAT and has based 

today’s requirements on Option 2. 
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C. NSPS 

 EPA evaluated “best available demonstrated control technologies” for purposes of setting 

new source performance standards under CWA section 306. Among the collection technologies 

for ADF that EPA considered, CDPs collect the greatest level of available ADF and are available 

to new sources in this industry. With respect to new airports, the use of CDPs does not present 

the space/land, safety or operational issues that would be raised in connection with the use of 

deicing pads at existing sources, nor are they so costly in comparison to the cost of a new airport 

that they would be considered a “barrier to entry.” 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 DCN XXXX. Therefore, EPA is promulgating NSPS requirements for ADF collection at 

new airports based on CDPs. 

 EPA is promulgating the same numeric COD limitations for collected ADF that is 

discharged directly for new sources as it is promulgating for existing sources. The technology 

basis, anaerobic fluidized bed system, is applicable to both existing and new airports. In 

addition, it achieves the greatest level of pollutant removals of those technologies considered 

during the development of this regulation. 

 EPA is similarly promulgating the same requirements associated with airfield deicing for 

new and existing sources. EPA determined that, just as with existing sources, all new sources 

would be capable of eliminating the use of urea containing deicers for airfield deicing in favor of 

substitute deicing products. Furthermore, product substitution represents the greatest level of 

reduction in ammonia among the available technologies considered. Accordingly, EPA 
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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. 

 For the purpose of this regulation, today’s final rule defines a “New Source” as a new 

airport. As discussed in Section IV.B above, EPA has revised the new source definition in the 

proposed rule and excluded new runways at existing airports from the definition. Meeting the 

new source requirements would not be an economic barrier to entry for new airports, as the cost 

of new airport construction, even at small airports is significantly greater than the costs 

associated with collection and/or treatment of spent deicing fluids. See Section VIII.E. 

D. PSES and PSNS 

EPA is not promulgating PSES and PSNS for the Airport Deicing Category. Although 

some airports in the U.S. discharge ADF-contaminated stormwater to publicly owned treatment 

works (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 employ biological treatment systems and are similarly designed to remove 

organic pollutants that contribute to COD and/or BOD5. In general, POTWs have the capability 

to achieve comparable removals to the BAT technology basis. However, some airports and 

POTWs may need to make operational adjustments in order to process the wastewater effectively 
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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 in order to segregate the deicing wastewater, collect 

and recycle the most concentrated ADF wastewater, and control the amount and concentration of 

wastewater discharged to the POTW. 

 EPA is aware that high concentration or “slug” discharges of deicing wastewater 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 § 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 

loading per day. These limits on daily pollutant loadings are specific to the receiving POTW. 

Airports usually meet this requirement by storing deicing stormwater in ponds or tanks and 

metering the discharge to meet the POTW permit loading requirements. 
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VII. Technology Costs and Pollutant Reductions 

A. Compliance Costs 

1. Overview 

 EPA estimated industry-wide compliance costs for today’s rule. This section summarizes 

EPA’s approach for estimating compliance costs, while the TDD provides detailed information 

on these estimates. All final cost estimates are expressed in terms of 2006 dollars and represent 

the cost of purchasing and installing equipment and control technologies, annual operating and 

maintenance costs, and associated monitoring and reporting requirements. In general this 

approach is the same as the one used in the proposal. However, some modifications were made 

for costing specific technology pieces in the costing models, including the numbers of GCVs per 

airport and the manner in which airports would store collected ADF containing wastewater. 

 EPA estimated compliance costs associated with today’s rule using data collected 

through survey responses, site visits, sampling episodes, specific airport requests and information 

supplied by vendors. Under this rule, certain airports would be required to collect a percentage 

of their available ADF and treat the collected wastewater to comply with numeric limitations if 

discharged directly. EPA estimated costs for an airport to install technology to comply with 

today’s requirements, as well as annually to operate and maintain equipment and perform 

required monitoring or other activities to demonstrate ongoing compliance. EPA’s cost 

estimates represent the incremental costs for a facility when its existing practices would not lead 

to compliance with today’s rule. 

 EPA calculated costs based on a computerized design and cost model developed for each 

of the technology options considered. EPA developed facility-specific costs for each of the 

airport industry questionnaire respondents (149 facilities), where each facility was treated as a 
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“model” airport. Because the questionnaire respondents represent a subset of the industry, EPA 

subsequently modeled the national population by adjusting the costs upward to estimate the 

entire affected airport population. 

 The questionnaire responses provided EPA with information on three consecutive deicing 

seasons (2002 to 2005) for each of the model facilities. Some portions of EPA’s costing effort 

reflect the airports' operations as reported for the three seasons. For example, estimates of 

applied deicing chemicals were taken as an average of the years for which the information was 

reported. In instances where aspects of an airport's operation changed over the three-year period, 

EPA used the most recent information. 

 EPA first established existing conditions (i.e., baseline) for each model airport based on 

information and site plans submitted as part of the airport questionnaire. EPA then determined 

what upgrades or changes, if any, would be required to comply with today’s final rule. For 

example, in general, when an airport lacked a comparable collection system to the one used as 

the basis for today’s rule, EPA included costs for installation/operation and maintenance of plugand-pump systems in conjunction with GCVs. 

2. Approach for Estimating Airfield Pavement Deicing Costs 

 Today’s rule sets requirements for an airport to certify it uses non-urea-containing airfield 

deicers. Through the airport questionnaire responses, EPA estimates that 198 airports will be 

subject to today’s requirements. Of these 198 airports, 37 airports use urea containing deicers 

for airfield pavement deicing. As detailed in Section V.D.4., EPA based its airfield pavement 

deicing requirement on product substitution. EPA calculated the cost for facilities to substitute 

the urea containing deicers with another widely available pavement deicer that does not produce 

ammonia in the wastewater. EPA chose to model the substitution costs on what it would cost to 
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switch to potassium acetate, specifically because that product accounts for 63 percent of the 

applied chemical airfield deicer usage (by weight) in the U.S. These incremental costs include 

capital costs associated with application equipment and storage, as appropriate, as well as the 

differential chemical costs. EPA assumed that those airports that currently do not use urea 

containing deicers as a means of pavement deicing would experience no cost associated with this 

portion of today’s regulation. 

 Using the facility area usage as provided in the airport questionnaire and available 

literature on typical urea-containing pavement deicer application rates, EPA estimated the 

airfield area that was annually deiced at each model facility. Using the estimated model facility 

deicing area in conjunction with the estimated $2.92/1,000 ft2

 cost of potassium acetate, EPA 

was able to calculate the cost per model facility to perform airfield deicing with potassium 

acetate. This cost was compared to the questionnaire reported urea containing deicer costs to 

determine the incremental costs of switching chemical airfield deicers. See the TDD for 

additional details on costing for airfield deicing product substitution. 

3. Approach for Developing Aircraft Deicing Costs 

 Under this rule, certain airports are required to collect a percentage of their available 

ADF, and treat the collected wastewater to comply with numeric effluent limitations if it 

discharges directly. EPA estimated the costs for an airport to comply with collection and 

treatment requirements, as applicable, as well as performing required monitoring to demonstrate 

compliance. Of the 198 airports subject to BAT, EPA expects that 55 airports will exceed the 

threshold for ADF use that would trigger the collection/discharge requirement. Costing for ADF 

collection is not relative to baseline practices in all instances, as an airport's existing collection 

technology may not be incrementally upgradeable to achieve the required collection efficiency. 
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As such, EPA assessed all costs to comply with today’s regulation with the assumption that any 

airport required to make upgrades to their collection and/or treatment system to meet today’s 

requirement, would be starting from a baseline of zero collection and treatment. Note that this 

assumption does not carry through to pollutant removals, as baseline removals are accounted for 

when assessing pollutant removals associated with today’s regulations (see section VII.B for 

more detail on the pollutant removal calculations). 

 EPA first established existing conditions for each model airport based on information and 

site plans submitted as part of the airport questionnaire. EPA then determined what upgrades, if 

any, would be required to comply with today’s requirements. As explained above, in general, 

when an airport lacked a comparable collection system to the one used as the basis for today’s 

rule, EPA included costs for installation/implementation of plug-and-pump systems in 

conjunction with GCVs and AFB treatment system. 

 For those airports that are required to collect additional ADF and meet associated 

discharge requirements to comply with today’s rule, EPA estimated costs for 

storage/equalization (and associated piping to transfer collected ADF to storage) as part of the 

costs of the treatment technology. 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. 

Where EPA estimates an airport will incur capital costs associated with ADF collection and 

discharge requirements, the Agency included costs for above-ground storage tanks, since aboveground storage tanks will have less of an impact on subsurface utilities, for which EPA does not 

have site-specific information. 
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 For the 15 airports that EPA anticipates will need to collect additional quantities of ADFcontaminated stormwater to comply with today’s rule, EPA assumed these additional quantities 

would be discharged directly, thus requiring treatment to comply with the COD limitations. This 

includes all airports that EPA estimates collect less than 40 percent of available ADF. 

Specifically, this includes those facilities that currently collect some portion of ADFcontaminated stormwater and subsequently discharge indirectly to a POTW or a centralized 

waste treatment (CWT) facility. EPA recognizes that an airport may decide to discharge to a 

POTW or CWT facility rather than directly discharge its wastewater. While this is likely a lower 

cost alternative in some cases, EPA did not assume that airports could discharge to a POTW or 

CWT, because the Agency does not have enough information about the capacity or willingness 

of a specific POTWs to receive these volumes of wastewater. To the extent that an airport 

selects this alternative, EPA may have over-costed the option. 

 Additionally, airports may have costs associated with permit application requirements or 

demonstrating compliance with today’s rule, including assessing yearly ADF usage, determining 

ADF stormwater collection, system inspections and COD monitoring. Monitoring requirements 

will continue to be determined by the permitting authority. However, for purposes of estimating 

monitoring costs associated with today’s rule, EPA assumed that airports that directly discharge 

collected ADF would take a 24-hour composite sample and analyze that for COD, and perform 

that analysis seven times per week for the duration the treated discharge occurs. EPA made a 

similar assumption for purposes of computing the weekly average effluent limitation (see the 

TDD for additional details). As a conservative estimate, EPA assumed a six-month discharge 

duration season for all modeled facilities. 

4. Calculation of National Costs 
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 EPA categorized all of the costs as either capital costs (one-time costs associated with 

planning or installation of technologies), or as operations and maintenance (O&M) costs (costs 

that occur on a regular ongoing basis such as monitoring or annual purchases of deicing 

materials). EPA amortized these capital costs over the lifespan of the capital improvement. For 

additional information on amortization, see the EA. Finally, EPA combined the amortized 

capital costs with the annual O&M costs to calculate the total annual cost of the regulation for 

that model facility. 

 EPA then utilized statistical weights assigned to each of the 149 model facilities to 

calculate a national estimated cost of $78 million for complying with the rule. Further discussion 

of all of the calculations discussed can be found in the TDD and in the EA. 

B. Approach to Estimating Pollutant Reductions 

1. Overview 

 The pollutants of concern associated with airfield and aircraft deicing and anti-icing 

chemicals are discussed in Section 6 of the TDD. These chemicals commingle with stormwater 

and may be discharged to the environment. These discharges are of environmental concern 

because the biodegradation of deicing chemicals results in oxygen depletion in the receiving 

water body. Moreover, some of these pollutants, such as ammonia, have toxic properties. 

Pollutant loadings from airport deicing operations are challenging to estimate because 

they 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 based on weather conditions. 

The pollutant loadings also vary from airport to airport based on each airport’s climate. In 

addition, the amount of applied chemical that is discharged to surface water is airport specific, 
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based on the existing stormwater separation, collection, and/or containment equipment present at 

each airport. 

 Due to the variable nature of these pollutant loads, EPA developed a baseline (or current) 

pollutant loading methodology based on the usage of ADF and airfield chemicals at the airports 

responding to the survey questionnaires. 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. Similar to the costing methodology, EPA developed facility-specific 

baseline loads for a subset of the industry (i.e., model facilities). For those model airports where 

existing practices would not lead to compliance with today’s rule, EPA then calculated the 

incremental pollutant removals associated with compliance. EPA subsequently adjusted the 

incremental pollutant removals upward to estimate the entire affected airport population. This 

approach is the same as the approach taken in the proposal. 

2. Sources and Use of Available Data 

 While developing the pollutant loading models, EPA considered the following data 

sources: 

 Pavement deicing chemical usage/purchase information for the 2002/2003, 2003/2004, 

and 2004/2005 deicing seasons, as reported by airport authorities in the Airport Deicing 

Questionnaire; 

 ADF purchase information for the 2002/2003, 2003/2004, and 2004/2005 deicing 

seasons, as reported by air carriers in the Airline Deicing Questionnaire; 

 Standard airport information available from the FAA and the Bureau of Transportation 

Statistics (BTS), including the number of operations and departures by airport; 
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 Weather information for each airport from National Oceanic and Atmospheric 

Administration (NOAA), including temperature, freezing precipitation, and snowfall 

data; 

 Existing airport stormwater collection and containment systems, as reported by airport 

authorities in the Airport Deicing Questionnaire; 

 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. 

a. Baseline Loading Calculations 

 The Agency estimated the total amount of pavement deicing chemicals and ADF used 

based on data collected in the Airport and Airline Questionnaires. The Airport Questionnaire 

respondents reported the purchase/usage amount, concentration, and brand name of pavement 

deicing materials. EPA collected ADF purchase data from airlines with 1,000 or more 

departures operating at selected airports through the airline questionnaire. (During questionnaire 

development, airports indicated they did not have information on ADF usage and that EPA 

should direct this question to airlines. Purchase data were collected because the airlines stated 

that purchase data were most readily available, while usage data was not.) For the purposes of 

these loading calculations, EPA estimated that the annual amount purchased was equal to the 

amount used for a deicing season. For instances where EPA did not have ADF purchase data for 

every airline operating at a particular model airport, EPA extrapolated the amount of ADF used 

by the reporting airlines to estimate the total amount of ADF used by the entire airport. This was 

done based on the number of airport operations (departures) at the reporting airlines versus the 

total number of airport operations. In addition to the 56 airports for which EPA collected ADF 
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purchase/usage data from the airline tenants, 10 airports reported the total volume of their ADF 

usage to EPA in their comment section of the Airport Deicing Questionnaire, resulting in 

estimates of total ADF usage for 66 model airports. 

 Using the airline and airport ADF purchase and usage data obtained from the 

questionnaire; airport departure data; and climate data, EPA developed a relationship between 

the amount of ADF used, and the climate and size of each model airport. EPA then used this 

equation to estimate the total gallons of ADF used at model airports that did not have ADF usage 

data in the Airport or Airline Questionnaires. (EPA is aware that a core component of today’s 

regulation is airport-specific ADF usage estimates. However in order to prevent mandatory 

survey responses marked as CBI from being released, EPA is not revealing the exact 

methodology for modeling this ADF usage due to the potential for the deduction of CBI data 

through back calculation). 

 Once the amount of ADF used at each model airport had been determined, EPA needed 

to determine the amount of ADF available for direct discharge. EPA assumes that 75 percent of 

applied Type I ADF falls onto the pavement at the deicing area and is available for discharge. 

EPA assumes 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. (See the TDD for more 

information on these estimates.) EPA then multiplied the total amount of applied ADF for each 

model airport by the appropriate percent available for discharge to determine the amount of ADF 

available for discharge. Note that collection requirements in the rule are specified as percentages 

of ADF available for discharge, not percentages of total ADF applied. Evaluating the amount of 

ADF available for discharge, coupled with the estimated baseline collection rate, results in the 
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total amount of discharged available ADF. EPA then calculated the amount of COD loading 

associated with these discharges as described below. 

 Airfield pavement deicing chemicals are applied at various airside locations such as 

runways, taxiways and ramps. Theoretically, the amount of pavement deicers being discharged 

could range from approximately zero percent, for chemicals that infiltrate highly permeable soils 

in unpaved areas during a thaw, to virtually 100 percent for paved areas near storm drains. In 

general, soil in unpaved areas is frozen during deicing season and is impermeable, promoting the 

overland flow of stormwater and pollutants to surface waters. Estimating the amount or 

proportion of pavement deicers discharged at a particular airport is difficult without performing a 

detailed study at the airport. EPA has not received any such detailed studies, nor other 

information from airports indicating that pavement deicers are absorbed into soil during the 

deicing season. Therefore, the Agency assumed for this rulemaking that 100 percent of the 

pavement deicers used could be discharged to surface waters. This means the estimates of 

baseline pollutant loadings and removals associated with pavement de-icing are upper bound 

estimates. EPA then calculated the amount of COD loading associated with airfield chemical 

use and discharge as described below. 

 To calculate the COD loading associated with either ADF or airfield chemical discharge, 

EPA determined the theoretical oxygen demand (ThOD) associated with the degradation of each 

of the deicing chemicals. EPA based the ThOD estimate 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. 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 
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calculated mass of the chemical discharged, the molecular weight of the chemical, the ThOD, 

and the molecular weight of oxygen. EPA estimated the ammonia load associated with deicers 

containing urea on the chemical equation for the breakdown of urea to ammonia, the mass of 

urea use, and the molecular weights of urea and ammonia. See Section 9 of the TDD for more 

information and example calculations of baseline loadings associated with ADF and airfield 

deicers. 

b. Calculation of Pollutant Removals 

 After determination of baseline loadings, EPA calculated total reductions of COD and 

ammonia associated with a national implementation of today’s rule. 

i. Aircraft Deicing Related Pollutant Removals 

 EPA estimated the amounts of COD that would be reduced by the rule, by estimating the 

existing baseline loadings associated with aircraft deicing at model airports and comparing that 

to the COD load that would be discharged after complying with the rule (i.e., COD load 

discharged if 40 percent of available ADF were collected and treated to meet the required 

discharge limitation). If a particular airport would be subject to a collection requirement of 40 

percent under this rule and it currently is estimated to collect a greater proportion of available 

ADF, then no load removals were estimated for that airport. 

ii. Airfield Deicing Related Pollutant Removals 

 EPA calculated ammonia and COD baseline loads for those model facilities using deicers 

containing urea. The Agency then calculated ammonia and COD loads for those same model 

facilities if they replaced their deicers containing urea with the substitute product, potassium 

acetate (which does not form ammonia and exerts a lower COD than urea). EPA computed the 
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total load reduction by subtracting the ammonia and COD loadings between the baseline and the 

regulatory compliance conditions. 

iii. National Extrapolation 

These calculated loading reductions, summed for both airfield and aircraft deicing chemicals, as 

applicable, were then extrapolated by multiplying the pollutant removals for each model facility 

by the airport survey weighting factors to determine national loads for the entire industry for 

each regulatory option considered for today’s rule. 

C. Approach to Determining Long-Term Averages, Variability Factors and Effluent Limitation 

Guidelines and Standards 

 This section describes the statistical methodology used to develop the daily maximum 

and the maximum for weekly average effluent limitations and new source performance standards 

representing the BAT and BADCT levels of control for COD. EPA also used the same statistical 

methodology to develop the daily maximum limitation/standard for ammonia that is a 

compliance alternative when deicers containing urea are applied to runways. For simplicity, the 

following discussion uses the term “limitation” to refer to effluent limitations guidelines, 

standards, and the compliance alternative. EPA has promulgated the same limitations for each 

level of collection requirement, because the treatment technology and performance are the same 

regardless of the amount of fluid collected. 

 The following sections describe the data selection criteria; the statistical percentile basis 

of the effluent limitations; rationales for certain limitations; the calculations; the recommended 

long-term average value for treatment operations; and the engineering evaluation of the model 

technology’s ability to achieve the levels required by the limitations. 

1. Criteria Used to Select Data as the Basis of the Limitations 
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 Typically, in developing effluent limitations for any industry, EPA qualitatively reviews 

all the data before selecting the appropriate data to use for calculating the limitations. EPA 

typically uses four criteria to assess the data. One criterion generally requires that the influent 

and effluent represent only wastewater from the regulated operations (e.g., deicing), and do not 

include wastewater from other sources (e.g., sanitary wastes). A second criterion typically 

ensures that the pollutants were present in the influent at sufficient concentrations to evaluate 

treatment effectiveness. A third criterion generally requires that the facility must have the 

technology and demonstrate proper operation of the technology. A fourth criterion typically 

requires that the data cannot represent periods of treatment upsets or shutdown and start-up 

periods. (Shutdown periods can result from upset conditions, maintenance, and other atypical 

operations.) 

 EPA has adapted the application of the fourth general criterion for data corresponding to 

start-up periods to reflect some unique characteristics of treating discharges from aircraft deicing 

operations. Most industries incur start-up conditions only during the adjustment period 

associated with installing new treatment systems. During this acclimation and optimization 

process, the concentration values tend to be highly variable with occasional extreme values (high 

and low). After this initial adjustment period, the systems should operate at steady state for years 

with relatively low variability around a long-term average. Because start-up conditions 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 beginning 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 has 

included start-up data in the data set used as the basis of the limitations. However, through its 
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application of the other three criteria, EPA excluded extreme conditions that do not demonstrate 

the level of control possible with proper operation and control even during start-up periods. For 

detailed information on these exclusions, see Section 14 of the TDD. 

 In part, by retaining start-up data for the limitation’s 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 for the collected deicing fluid to run continuously until the end of the deicing season. 

2. Data Used As Basis of the Effluent Limitations 

 As explained in Section 8 of the TDD, the technology basis for the COD numerical 

limitations associated with discharges of collected ADF wastewater is anaerobic fluidized bed 

(AFB) biological treatment. Of the effluent data available to EPA, 2,562 concentration values 

for COD met the requirements in the criteria described above and are the basis of the COD final 

effluent limitations. The concentration values are measurements of filtered effluent collected 

from Albany Airport’s two-unit anaerobic treatment system. The 2,562 COD values were 

collected by the airport during its daily monitoring of COD over ten deicing seasons (i.e., 

December 1, 1999 through April 10, 2009). 

 The basis for today’s effluent limitation regarding airfield deicing chemicals is product 

substitution. EPA also established ammonia discharge limitations as a compliance alternative. 

Ammonia naturally occurs in airport discharges as a result of excretions from wildlife that enter 

the stormwater; therefore, EPA determined it would not be appropriate to set this limitation at the 

non-detect level. Moreover, depending on a specific airports' drainage system, a portion of 

airfield deicing stormwater may be routed to the treatment system utilized in treating the 

collected ADF. Further, the anaerobic biological treatment system (AFB) that is identified as 
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BAT/BADCT for treating collected ADF will itself produce ammonia discharges as a byproduct 

of treatment. Therefore, where airfield deicing stormwater that is free of urea contamination is 

routed through the AFB treatment system, the discharge after treatment may have ammonia 

concentrations higher than the non-detect level (see DCN xxx). Consequently, EPA used 

ammonia effluent discharge data from the same AFB system it used to establish BAT/BADCT 

discharge requirements for ADF, located at Albany, to establish today’s ammonia compliance 

alternative. Five ammonia concentration values available from Albany met the limitations 

criteria described above. The five ammonia values were collected by EPA during its sampling 

episode (February 5 through February 9, 2006). 

3. Statistical Percentile Basis for Limitations 

 EPA uses a statistical framework to establish limitations that well-operated facilities are 

capable of complying with at all times. By well operated facilities, EPA means facilities that 

represent the BAT/BADCT level of control. 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 variability 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 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 
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limitations be based on the best available technologies (or BADCT for new sources), including 

proper operation and maintenance of these technologies. 

 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 a well-operated system. This variability means that at certain times 

airports may discharge at a level that is greater than the long-term average. This variability also 

means that airports may at other times discharge at a level that is 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). EPA has consistently used the 99th

percentile as the basis of the daily maximum limitation in establishing limitations for numerous 

industries for many years and numerous courts have upheld EPA’s approach. EPA typically 

establishes limitations based upon statistical percentile estimates and has done so for the weekly 

average limitation in today’s final rule. 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 of a weekly 

average of the daily measurements is a logical extension of this practice. Compliance with the 

daily maximum limitation is determined by a single daily value; therefore, EPA considers the 

99th percentile to provide a reasonable basis for the daily maximum limitation by providing an 

allowance for an occasional extreme discharge. Because compliance with the monthly average 
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limitation is based upon more than one daily measurement and averages are less variable than 

daily discharges, EPA has determined that facilities should be capable of controlling the average 

of daily discharges to avoid extreme monthly averages above the 95th percentile. In a similar 

manner 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. Consequently, EPA has determined that the 97th percentile is 

an appropriate basis for limiting average discharges on a weekly basis. EPA considers the use of 

the 97th percentile for the weekly average limitation a level that is achievable for airports using 

the model technology. EPA also considers this level of control in avoiding extreme weekly 

average discharges to be possible for airports using the model technology. 

4. Rationale for Establishing Limitation on Weekly Averages Instead of Monthly Averages for 

COD in Effluent Discharges 

 From a monitoring perspective, EPA considers the weekly average limitation to be a 

better fit than the monthly average limitation for the deicing discharges. In this situation, the 

weekly average limitation would apply to every week that the treatment system operates during 

the deicing season. A weekly average limitation preserves EPA’s intention for an additional 

restriction beyond the daily maximum limitation that supports its objective of having airports 

control their average discharges at the long-term average level. 

 When it establishes monthly average limitations, EPA’s objective is to provide an 

additional restriction to help ensure that facilities target their treatment systems to achieve the 

long-term average. The monthly average limitation requires facilities to provide on-going 

control that complements controls imposed by the daily maximum limitation. To meet the 
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monthly average limitation, a facility must counterbalance a value near the daily maximum 

limitation with one or more values well below the daily maximum limitation. To achieve 

compliance, these values must result in a monthly average value at or below the monthly average 

limitation. 

 The deicing season is unlikely to start at the beginning of a calendar month and close 

exactly at the end of a calendar month. This means that the facility would be monitoring at a 

reduced frequency during those two months. Increasing or decreasing monitoring frequency 

does not affect the statistical properties of the underlying distribution of the data used to derive 

the limitations. However, monitoring less frequently theoretically results in average values that 

are more variable. For example, monthly average values based on 10 monitoring samples per 

month would be (statistically) expected to include some averages that are numerically larger (as 

well as some that are numerically smaller) than monthly average values based upon 20 

monitoring samples. Because of this reduced monitoring, an airport might have trouble in 

complying with the monthly average limitation even with an otherwise well-operated and 

controlled system. In other words, because it was not monitoring as frequently, the airport would 

have fewer opportunities to counterbalance high concentrations with lower values. 

5. Rationale for Promulgating a Limitation Only for Daily Discharges of Ammonia in Effluent 

Discharges 

 EPA believes that it is appropriate to rely on a daily maximum limitation to ensure that 

airports appropriately control ammonia levels as airports might have difficulties in complying 

with any average limitation due to monitoring less frequently than assumed in the statistical 

calculations (see discussion related to monitoring for COD). Unlike for the COD limitation, 

EPA is not promulgating a weekly ammonia effluent limitation. The technology basis for the 
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COD effluent limitations would operate throughout the deicing season with continuous 

discharges allowing for weekly monitoring. In contrast, urea containing deicers are 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 non-continuous 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. 

 Additionally, EPA expects airports to select product substitution (i.e., non-urea deicers) 

rather than the compliance alternative that requires collection and treatment of runway deicing 

contaminated stormwater. Thus, it is possible that no airports will be subject to any limitation on 

ammonia discharges. 

6. Calculation of Limitations for COD and Ammonia 

 For COD, EPA used nonparametric statistical methods to estimate the percentiles used as 

the basis of the daily maximum and weekly average limitations. A simple nonparametric 

estimate of a particular percentile (e.g., 99th) of an effluent concentration data set is the observed 

value that exceeds that percent (e.g., 99) of the observed data points. 

 For the daily maximum limitation for COD, EPA used the nonparametric method to 

derive a 99th percentile of the more than 1,200 daily measurements for each unit, and then set the 

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. In this particular case, because there are two units, the median is equal to the arithmetic 

average (or mean). 
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 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. EPA 

then used the nonparametric method to derive a 97th percentile of the more than 200 weekly 

averages for each unit, and set the limitation equal to the median of the two 97th percentile 

estimates, or 154 mg/L. 

 For ammonia, EPA used a parametric approach in estimating the 99th percentile based 

upon the data collected during EPA's 5-day sampling episode. The calculations assume the 

ammonia concentrations can be modeled by a lognormal distribution. EPA's selection of 

parametric methods, such as a model based on the lognormal distribution, used in developing 

limitations for other industries is well documented (e.g., Iron and Steel (40 CFR part 420), Pulp, 

Paper and Paperboard (40 CFR part 430), Metal Products and Machinery (40 CFR part 438) 

categories). Variance estimates based upon parametric methods can be adjusted for possible 

biases in the data. The limitation of 14.7 mg/L includes such an adjustment for possible bias 

from positive autocorrelation. When data are positively autocorrelated, it means that 

measurements taken close together in time (such as 1 or 2 days apart) are more similar than 

measurements taken farther apart in time, such as a week or month apart. The adjusted variance 

then better reflects the underlying variability that would be present if the data were collected 

over a longer period. 

7. Derivation of Long-Term Average for COD and Ammonia: Target Level for Treatment 

 Due to routine variability in treated effluent, an airport that discharges consistently at a 

level near the values of the daily maximum limitation or the weekly average limitation, instead 

of the long-term average, may experience frequent values exceeding the limitations. For this 

reason and as noted previously in this section, EPA recommends that airports design and operate 
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the treatment system to achieve the long-term average for the model technology. Thus, a system 

that is designed to represent the BAT/BADCT level of control will be capable of complying with 

the promulgated effluent limitations. 

 For COD, EPA recommends that airports target treatment systems to achieve the longterm average value of 52.8 mg/L, which is the median of the two averages, of 52.28 and 53.40 

mg/L, of the daily values from the two units. The daily 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 of 271 mg/L is about five 

times greater than the long-term average achievable by the model technology. The weekly 

variability factor is 2.92. 

 For ammonia, EPA derived its recommended long-term average value of 5.24 mg/L from 

the (statistical) expected value of the lognormal distribution. The daily maximum limitation of 

14.7 mg/L is about three times greater than the long-term average, of 5.24 mg/L, achievable by 

the ADF treatment model technology. 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. 

8. Engineering Review of Effluent 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 facility conditions. During the site visit and sampling trip at the 

Albany treatment plant, EPA confirmed that the airport used the model technologies, specifically 
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AFB. EPA subsequently contacted the plant personnel to obtain more information about the 

installation and operation of the model technologies. EPA used this engineering information to 

select the subset of data from which to develop the effluent limitations. 

 As part of this engineering review, EPA concluded that the values of the limitations were 

consistent with the levels that are achievable by the model technologies. Next, EPA compared 

the value of the effluent limitations to the data values used to calculate the limitations. None of 

the data selected for ammonia were greater than its daily maximum limitation which supports the 

engineering and statistical conclusions that the limitation value is appropriate. Because of the 

statistical methodology used for the COD limitations (i.e., use of percentiles), some values were 

appropriately greater than the limitations. See section VII.C.3. Even though we would expect 

this statistically, EPA looked at the values that exceed the limitations from an engineering 

perspective. EPA wanted to ensure there were no underlying conditions contributing to such 

exceedances. In particular, EPA looked at deicing season, influent concentrations, and start-up 

operations. In evaluating the impact of the deicing seasons, EPA concluded that the higher 

values did not seem to be predominant in any one season. In particular, the higher values 

occurred one to seven times in each of eight seasons. In evaluating influent concentrations, EPA 

found that influent concentrations were generally well-controlled into the treatment plant. In 

general, the treatment system adequately treated even the extreme influent values, and the high 

effluent values did not appear to be the result of high influent discharges. In considering start-up 

operations, EPA noted that the higher values occurred in every month from December through 

May, except in April, and thus, the limitations appear to provide adequate allowance for start-up 

operations. 
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VIII. Economic Analysis 

A. Introduction 

 EPA’s economic analysis assesses the costs and impacts of the final effluent guidelines 

on the regulated industry. This section explains EPA’s methodology and the results of its 

economic analysis. With one exception, all costs, airport counts and other results in this section 

are presented using sample weights to expand results from the surveyed airports to represent the 

entire population of airports potentially affected by the rule. The single exception, the results of 

the debt service coverage analysis, is clearly marked as “unweighted.” In addition, all cost 

figures are presented in 2006 dollars. 

B. Annualized Compliance Cost Estimates 

 EPA considered two regulatory options for today’s final rule. Under both, all airports 

subject to BAT or NSPS would have requirements with respect to airfield deicing stormwater 

(certify no use of airfield deicing products that contain urea, or airfield pavement discharges 

must achieve a numeric limit for ammonia). EPA estimates that 198 airports—those that 

perform deicing operations with at least 1,000 annual non-propeller aircraft departures--are 

subject to the airfield deicing requirements.1

 In addition, a subset of those airports—airports 

with annual normalized ADF usage equal to or exceeding 60,000 gallons per year (55 airports)—

would also need to meet requirements related to wastewater from aircraft deicing (ADF 

collection and COD discharge limitations). The regulatory options that EPA considered differ in 

the level of ADF collection required for aircraft deicing. Option 1 would set a two-tier 

requirement: 20 percent collection and treatment for airports with at least 60,000, but less than 

 

1

 Because many airports do not meet the applicability criteria, EPA estimates that approximately 

184 primary airports, 135 non-primary airports, and almost 3,000 general aviation airports are 

not regulated under the final rule. 
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460,000 gallons of annual normalized ADF usage, and 40 percent collection and treatment for 

airports with at least 460,000 gallons of annual ADF usage. Option 2 would require 40 percent 

collection and treatment for all airports with at least 60,000 gallons of annual normalized ADF 

usage. 

 EPA selected Option 2 for promulgation in this final rule. EPA estimates the technologies 

identified in this notice to comply with the BAT limitations will cost affected airports $314.4 

million in total capital costs over 20 years in nominal terms 

 EPA projects the effective service life of glycol collection vehicles (GCV) and blockand-pump technologies to be 10 years; all other components necessary to meet today’s 

requirements have an effective service life of 20 years. Therefore, EPA selected a 20 year 

analytic period and incorporated replacement capital expenditures in year 10, in addition to the 

initial capital expenditure. As such, we estimated total capital costs to include all initial and 

replacement capital expenditures for GCV and plug-and-pump. However, because the 

replacement capital expenditures occur 10 years after promulgation, the discounted present value 

(PV) of those expenditures is less than their current value. 

EPA uses 3 and 7 percent interest rates for two purposes. First, it is used to discount 

future capital replacement costs required when the 20-year analytic period exceeds the effective 

service life of a technology. Second, it represents the opportunity cost of capital to industry, and 

thus, essentially the interest rate the industry may be charged if it borrows money. 

EPA discounted and annualized the stream of capital costs projected to be incurred by 

industry over 20 years using two different discount rates. EPA has determined that a 3 percent 

real discount rate best represents society’s preferences for future consumption of goods and 

products, including improved environmental conditions (EPA. 2010. “Guidelines for Preparing 
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Economic Analyses.” Document no. EPA-240-R-10-01). Thus, discounting and annualizing the 

future stream of costs using a 3 percent real discount rate best represents the cost of the rule to 

the nation as a whole. However, in order to be able to continue to attract capital in the long run, 

businesses would be expected to meet the opportunity cost of capital; therefore capital costs are 

also using a 7 percent real rate (as determined by OMB) to represent the long-term opportunity 

cost of capital to industry. The PV of capital costs under the final rule is $309.0 million based on 

the societal discount rate of 3 percent, and $299.0 million over the 20-year analytic period using 

the 7 percent private opportunity cost of capital rate. 

 The annual cost of operating and maintaining the technologies identified as BAT for 

deicing for this final rule, is estimated at $52 million. Adding this operation and maintenance 

cost to the annualized capital costs, the rule has aggregate national costs of $72.1 million per 

year using a 3 percent discount rate and annualized costs to industry of $78.4 million using a 7 

percent rate (in 2006 dollars). Table VIII-1 presents projected costs for the final rule, as well as 

the other option examined. 

Table VIII–1. Costs to Existing Airports that Deice Aircraft and Airfield Pavement 

[2006 $ millions – 198 airports (weighted)] 

Option 

Total 

Capital 

Costs 

Present 

Value of 

Capital 

Costs 

Annualized 

Capital 

Costs 

Annual 

O&M Costs 

Total 

Annualized 

Compliance 

Costs 

3 Percent Real Discount Rate 

1 $250.3 $243.7 $15.9 $28.4 $44.3 

2 [a] $319.9 $309.0 $20.2 $52.0 $72.1 

7 Percent Real Discount Rate 

1 $250.3 $237.6 $21.0 $28.4 $49.4 

2 [a] $319.9 $299.0 $26.4 $52.0 $78.4 

[a] Selected option. 
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C. Economic Impact Methodologies 

For the purposes of the economic impact analysis, the distinguishing feature of airports 

that makes the analysis different from more traditional analyses EPA would perform for a forprofit manufacturing industry is that all potentially affected airports are publicly owned and 

operated by local, county, or state governments, or by quasi-governmental authorities created to 

operate the airport. As governmental or quasi-governmental entities, airports do not earn a profit 

or loss in the traditional financial sense; in fact, many airports have been operated with the 

expectation that they will break even financially, with the airlines that use the airport legally 

required to cover expenditures in excess of costs. 

Airlines may also be impacted by today’s rulemaking. In the vast majority of cases 

airlines are not directly subject to today’s requirements. In such cases, impacts to airlines are 

considered secondary impacts. Historically, EPA determines economic achievability based on 

primary or direct impacts only (i.e., impacts to NPDES permit holders directly subject to ELG 

requirements) and does not evaluate secondary impacts. At the time of the proposal, EPA 

elected to evaluate secondary impacts to airlines because of the unique contractual relationship 

between airports and airlines, because airlines are the entities that use ADF, and because airlines 

are occasionally co-permittees (but never the principal permittee) at an airport. 

In a revision from proposal and consistent with past effluent guideline economic 

achievability analyses, for today’s final rule, EPA determined economic achievability based on 

primary or direct impacts only. EPA returned to its historical approach of evaluating economic 

achievability to only primary impacts (here impacts on airports and airline co-permittees) for 

today’s final rule because the Agency concluded that ultimately these entities will be responsible 

for incurring the costs and associated impact of any additional regulation. 
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In the analyses described below, EPA first evaluates the economic achievability of the 

rule assuming all costs are borne by airports, and the summaries of impacts to airports are based 

on that assumption. EPA also presents an analysis that shares compliance costs between affected 

airports and their co-permittee airlines, as applicable. Therefore, impacts to co-permittee airlines 

presented below are not in addition to the impacts to airports. To the extent that airports share 

costs with co-permittee airlines according to EPA assumptions, the costs and impacts to airports 

are reduced. This analysis is described in detail in the rulemaking record DCN XXXX. The 

following describes the methodology and the results EPA used to evaluate economic impact 

associated with the two regulatory options considered for today’s final rule, both under the 

assumption that airports incur 100 percent of compliance costs, and the assumption that airports 

share compliance costs with co-permittee airlines. 

1. Cost Annualization 

The first step in projecting the economic and financial impacts of the regulatory options 

rule is cost annualization. EPA projected the capital and operating and maintenance costs of the 

two regulatory options for each airport, then annualized those costs over 20 years. The method 

for estimating each airport’s capital and operating costs is described in Section VII.A. 

EPA used airport-specific interest rates based on recent General Airport Revenue Bonds 

(GARBs) issues to annualize compliance costs for the proposed rule. Based on public comments 

arguing that EPA underestimated the cost of capital to airports, EPA used a higher real interest 

rate of 7 percent to annualize airport capital costs for the final rule. However, EPA believes 

many airports will issue tax-exempt GARBs to fund capital expenditures. To the extent that 

airports use GARBs, it will lower the cost of capital, and reduce impacts to the financial health 

of the airports. EPA does not assume that airports will be able to fund capital expenditures using 
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Airport Improvement Program (AIP) grants or Passenger Facility Charges (PFCs) because such 

funds are likely to already be committed to airport projects into the foreseeable future. However, 

to the extent that airports might use AIP or PFC funds for capital expenditures associate with this 

rule, it will also lower the cost of capital, and reduce impacts to the financial health of the 

airports relative to what EPA has projected in its analysis. 

2. Airport Impact Methodology 

Because all in-scope airports are nonprofit government or quasi-government entities (e.g., 

port authority), the effect of an effluent guideline on airport income statements and balance 

sheets is not best measured by a traditional closure analysis. Therefore, EPA chose to examine 

the financial impacts of the regulatory options using two measures. First, EPA compared total 

annualized compliance costs with airport revenues. Second, because many airports fund capital 

expenditures using debt financing, EPA examined the impact of additional debt on each airport’s 

debt service coverage ratio. 

a. Revenue Test 

EPA's "Guidelines for Preparing Economic Analyses" (2010) recommends the ''revenue 

test'' as a measure for impacts of programs that directly affect government and not-for-profit 

entities. EPA finds that the revenue test is appropriate in this case. The revenue test compares 

the total annualized compliance costs of each regulatory option with the revenues of the 

governmental entities. Although the current Guidelines do not specify the use of one and three 

percent for the revenue test, EPA’s 2000 Guidelines did, and the Agency’s analysis for the 

proposed rule followed that guidance; EPA applied the same test here. 

The Guidelines (2010) suggest evaluating the affordability of a regulatory option as 

follows: 
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 If total annualized compliance costs are less than 1 percent of revenues, the option is 

generally considered affordable for the entity; 

 If total annualized compliance costs are greater than 3 percent of revenues, the option is 

generally considered not affordable for the entity. 

EPA used operating revenue as reported on Form 127 of the FAA’s Airport Financial 

Reporting Program as the denominator for the revenue test ratio, and total annualized compliance 

costs as described under Cost Annualization as the numerator for the ratio. 

Industry commenters on the proposed rule objected that the revenue test is too simplistic. 

EPA disagrees, and moreover, industry commenters were unable to provide any alternative test 

that would more accurately project economic impacts on the industry. Some industry 

commenters suggested that EPA examine different, more narrowly defined ratios, such as the 

ratio of compliance costs to aeronautical revenues, or the incremental cost per enplaned 

passenger. EPA did not choose to replace the revenue test with one of these variants because it 

determined that total operating revenues are the appropriate denominator for the test: the sole 

purpose of the airport is to support air transportation services. Landside revenues raised through 

parking, retail, and food concessions, for example, are not designed to provide a revenue stream 

to support the provision of a different service or product, but to allow airports to accumulate 

revenue from non-airline sources. Thus the intent of these revenue streams is also to support the 

provision of air transportation services and is therefore a component of an airport’s resources 

relevant to its implementation of these effluent limitation guidelines. Furthermore, industry 

commenters offered no suggestions for alternative thresholds for finding airport impacts, and, in 

fact, acknowledged that such thresholds do not exist in the case of their recommended 

incremental cost per enplaned passenger test. EPA did, however, perform several of these 
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alternative tests as sensitivity analyses and determined that the resulting projections of economic 

impacts to the industry did not differ significantly from those under the revenue test analysis. 

b. Debt Service Coverage Ratio 

When creating quasi-governmental agencies such as port authorities, the legislation that 

created the agency typically includes a lower limit on the authority’s debt service coverage ratio 

(DSCR). Airports owned and operated directly by a state or local government might also have 

direct limits on airport debt (if the airport has authority independent of the city or county 

government to incur debt). The authority will be in default on its debt if the DSCR falls below 

the relevant benchmark. A review of Comprehensive Annual Financial Reports (CAFR) for 

affected airports shows that generally the ratio of net revenues to debt service for any given year 

cannot fall below 1.25. Therefore, EPA estimated the impact debt financing will have on the 

post-regulatory DSCR for each airport incurring capital expenditures under the promulgated rule. 

From the Airport Questionnaire responses, EPA collected each airport’s current DSCR, 

and the net revenues and debt service used to calculate that ratio. For airports that belonged to 

multi-airport systems under the same ownership, DSCR was reported at the level of the entire 

system. Therefore, for each regulatory option, EPA aggregated compliance costs for all affected 

airports in the system, and performed a single calculation for the post-regulatory DSCR. 

Some evidence suggests airports will pass on less than 100 percent of costs, at least in the 

short run, if there is concern an airline might withdraw service if the airport increases fees too 

much. This might occur if the airport has nearby competitors, or if airline finances are fragile. 

EPA wanted to determine if an airport would be in danger of default on its debt even if it was 

unable to pass through option costs to its airline customers. Thus, the Agency calculated post-
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regulatory DSCR in two ways: (1) assuming costs are passed through to airlines in the form of 

higher landing fees, and (2) assuming no costs are passed through. 

In the baseline, the DSCR is calculated by dividing airport net revenues by airport debt 

service. Assuming 100 percent cost pass-through from airports to airlines, EPA estimated the 

post-regulatory DSCR of each regulatory option by: (1) assuming zero change in airport net 

revenues in the numerator (more precisely, EPA assumes that annual increase in landing fees are 

exactly equal to incremental annualized deicing costs, thus leaving net revenues unchanged), and 

(2) adding the annualized value of capital compliance costs to debt service in the denominator. 

The DSCR decreases even when assuming 100 percent cost pass-through: although the value of 

the numerator is unchanged, the denominator increases by the amount equal to annualized capital 

cost, decreasing the value of the ratio. 

Assuming no cost pass-through from airports to airlines, EPA estimated the postregulatory DSCR by for each regulatory option by: (1) subtracting incremental annual deicing 

operating and maintenance costs from pre-regulatory airport net revenues in the numerator, and 

(2) adding the annualized value of capital compliance costs to debt service in the denominator. 

With zero cost pass-through, the numerator in the ratio decreases because incremental O&M 

costs are subtracted from existing revenues, while the denominator increases because 

incremental debt is added to existing debt; thus, the DSCR clearly falls. 

All additional analyses, their methodology, justification, and results, are presented in the 

Economic Analysis for Final Effluent Limitation Guidelines and Standards for the Airport 

Deicing Category (EA), Document No. EPA-821-R-______. 
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3. Co-Permittee Airline Impact Methodology 

In response to public comment, EPA examined potential economic impacts to airlines 

that are directly subject to today’s final regulation: those that are co-permittees on NPDES 

permits. EPA conducted analyses of impacts to airlines that are co-permittees at certain airports, 

under the assumption that co-permittee airlines would directly pay a share of the airport’s 

compliance costs. EPA identified airline co-permittees through EPA’s Airport Deicing 

Questionnaire, where airports had been asked to identify all co-permittees. While the 

questionnaire responses identified co-permittees, they did not provide any data or insight into 

how permit-related compliance costs are currently distributed to, and among, co-permittees, if at 

all. Although the general outlines of standard contractual relations between airports and airlines 

can be characterized (see section 2.8 of the EA), the inclusion of an airline on the airport’s 

NPDES permit is not a common practice. In addition to reviewing information supplied in the 

questionnaires, EPA searched publicly available information, reviewed comment responses, and 

inquired with airline representatives on such relationships. Industry representatives did not 

provide EPA with information on these contractual relationships in the questionnaires or their 

comments on the proposed rule, nor did they provide this information to the Agency in preproposal meetings that were arranged to discuss the economic methodology of the rule. EPA 

was unable to gather any specific insight into these relationships and a distribution of compliance 

costs among the principal NPDES permit holder and its co-permittees. Thus, for purposes of this 

analysis, EPA assumed compliance costs would be distributed equally among the principal 

permittee (i.e., airport) and its co-permittee airlines. EPA recognizes that some individual 

airports may share a higher percentage of the compliance costs with its co-permittees and others 
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may share a lower percentage. However, for purposes of a national analysis, and with a lack of 

informative data, EPA finds a 50 percent distribution assumption to be reasonable. 

EPA does not separately assign capital costs to airlines and annualize those costs using 

airline-specific costs of capital; it seems more likely that with responsibility for the physical site, 

the airport would take the lead and have those costs reimbursed by the co-permittees. Thus, EPA 

assigned 50 percent of the total annualized compliance costs collectively to the co-permittee 

airlines. For each model airport with co-permittees, EPA needed to determine how to apportion 

the co-permittee portion of the compliance costs to the individual co-permittees. As explained 

above, EPA does not have data to determine if co-permittees currently incur any permit 

compliance-related costs nor, if they do incur those costs, how they are distributed among copermittees at individual airport locations. In the absence of specific information, EPA chose to 

attribute airport-specific compliance costs to each co-permittee based on its share of total landed 

weight at the airport. EPA chose this method because ADF usage should be roughly 

proportionate to the number and type of aircraft an airline typically uses at the airport, and 

therefore the costs of collecting and treating that ADF. Share of landed weight can be 

considered a simple summary measure that reflects both relative usage and aircraft size. This 

approach is also consistent with how airports typically attribute airside operational costs to 

airlines. EPA then calculated an airline’s total compliance costs by summing its airport-specific 

compliance costs over all airports at which the airline is a co-permittee. Finally, each airline’s 

compliance costs are compared to its system-wide operating revenue, operating profit, and net 

income. 

The comparison of one year’s average annualized compliance costs with operating profit 

and net income is consistent with a typical economic impact analysis. In a typical economic 
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impact analysis, EPA would project the affected entities’ discounted compliance costs and cash 

flow over the period of analysis. If an entity’s pre-regulatory discounted cash flow is positive, 

and its post-regulatory discounted cash flow is negative (i.e., projected pre-regulatory discounted 

cash flow less discounted compliance costs), the entity would be projected to close as a result of 

the effluent guideline. EPA then typically examines economic achievability by looking at the 

total number of closures relative to the total number of in-scope companies. In this case, if 

average compliance costs in one year exceed average operating profit or net income for that year 

(i.e., the ratio of compliance costs to operating profit or net income is greater than 100 percent), 

the airline can be projected to “close” as a result of the effluent guideline. 

However, such an analysis is problematic for airlines, for a number of reasons. First is 

the problem of “baseline closures.” A baseline closure is an entity with negative income prior to 

the promulgation of the effluent guideline. A baseline closure cannot be evaluated on the basis 

described above because the logic of that analysis requires that the entity’s pre-regulatory 

income be greater than zero. As amply documented in the Economic Analysis document (and 

updated in DCN XXXX), the last decade has been financially difficult for the airline industry, 

and approximately half the U.S.-flag airlines incurring compliance costs as co-permittees under 

normal circumstances would be categorized as “baseline closures” and could not be analyzed by 

this standard. 

Second, airlines have many options they can undertake in response to increased costs, 

short of going out of business. For example, airlines have the option to change service to a 

particular airport by increasing fares, decreasing service frequency, using different (typically 

smaller) aircraft, eliminating destinations flown to directly from that airport, or even eliminating 

service altogether to that airport. 
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To address the baseline closure issue, EPA included airline operating revenue as a third 

measure against which compliance costs can be compared, along with operating profit and net 

income. The purpose of using operating revenue is solely because such a large proportion of the 

airline industry cannot be evaluated due to negative baseline operating profit and/or net income: 

23 of 46 co-permittee airlines with financial data available have negative baseline operating 

profit, and 25 of 46 have negative baseline net income. Furthermore, classifying an entity as a 

“baseline closure” does not mean it will necessarily close; a business entity might earn negative 

operating profit or net income at some point in its financial history without closing permanently, 

and this appears to be particularly prevalent in the airline industry (see, for example, the Industry 

Profile in the Economic Analysis document). Rather than ignore roughly half of all co-permittee 

airlines, EPA chose to evaluate them using the ratio of compliance costs to operating profit to 

determine if the rule imposes costs that can be characterized as “relatively small.” The primary 

drawback of using operating revenue to measure economic impacts is that, unlike with operating 

profit or net income, there is no obvious threshold that determines what is economically 

achievable. 

To respond to the issue of changing service levels at an airport, it would also be 

informative to perform, if possible, a closure analysis at the route level for each airline’s routes 

associated with airports. However, EPA does not have available, nor could it reasonably obtain, 

airline financial data at either the route level or the airport level. Therefore, EPA must evaluate 

impacts to co-permittee airlines based on the only level at which airline financial data are 

available: their system-wide operations. 
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D. Results of Impact Analysis 

1. Results of Airport Impact Analysis 

a. Revenue Test Impact Results 

As noted in the previous section, EPA examined a number of alternative measures of 

economic impacts for airports in response to public comments on the proposed rule. However, 

EPA found none of these alternative approaches to be preferable. None of them provided a clear 

dividing line for determining what impacts might or might not be economically achievable for 

airports. That is, even if EPA selected one of industry’s measures, EPA would still have to 

determine some threshold that distinguishes impacts that are economically achievable from those 

that are not; industry did not provide such thresholds with their preferred measures, and for one 

measure specifically stated they did not know what the appropriate threshold would be. 

Nevertheless, EPA did perform sensitivity analyses to determine what effect the use of these 

alternative measures might have on our conclusions on economic achievability of the final rule. 

Our sensitivity analyses found that using these alternative measures would not substantively 

change the overall results on the final rule’s economic achievability. The results of these 

alternative analyses are not presented in this preamble, but are included in the EA as sensitivity 

analyses. 

Table VIII-2 shows the projected financial impact of the regulatory options considered 

for today’s rule. Under Option 1, airports would incur $49.4 million in annualized costs (7 

percent real interest rate), and 5 of the 198 airports (2.5 percent) are projected to incur costs 

exceeding 3 percent of operating revenue. One hundred seventy-six of the 198 airports subject to 

BAT (87 percent) are projected to incur annualized compliance costs composing less than 1 

percent of operating revenue. Under Option 2, airports would incur $78.4 million in annualized 
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costs (7 percent real interest rate), and 9 of the 198 airports (4.5 percent) are projected to incur 

costs exceeding 3 percent of operating revenue. One hundred seventy-two of the 198 BAT 

airports (87 percent) are projected to incur annualized compliance costs composing less than 1 

percent of operating revenue. Five airports do not have airport-specific financial data because 

they are part of Alaska’s Rural Aviation System, and therefore could not be analyzed. 

Table VIII–2. Financial Impacts of BAT Options on Airports that Deice 

[2006 $ millions – 198 airports (weighted)] 

Option 

Total 

annualized 

costs 

Number of airports with ratio of annualized compliance 

costs to operating revenue of: 

Less than 

1% 

Between 1% 

and 3% 

Greater 

than 3% Not analyzed [a]

1 $49.4 176 13 5 5 

2 [b] $78.4 172 13 9 5 

[a] Airports incurred compliance costs but owned by the state of Alaska; financial impacts 

could not be analyzed because Alaska does not track revenue data for these airports. 

[b] Selected option. 

b. DSCR Impact Results 

For multi-airport systems, the DSCR must be evaluated at the level of the owner, 

aggregating compliance costs incurred by all system airports. Thus, EPA analyzes entities 

owning single airports separately from multi-airport systems. Under today’s final rule, among 

owners of single airports, only one is projected to be in danger of default on its debt even if 100 

percent of compliance costs are assumed to be passed through to airlines; two additional airports 

are in danger of default if they are constrained in their ability to pass through costs to airlines 

(see Table VIII–3). EPA identified 9 multi-airport systems owning 21 airports projected to incur 

costs under the final rule, and analyzed costs for the 8 systems with data available. For the 8 

airport systems owning 16 BAT airports for which the debt service coverage ratio (DSCR) 

analysis could be performed, the results presented in Table VIII–4 show that today’s final rule is 
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projected to have no impact on the ability of airport authorities to finance debt. EPA did not 

analyze impacts to the DSCR for the Alaska Rural Aviation System (1 system owning 5 BAT 

airports) because Alaska does not use debt financing to fund this system. 

Table VIII–3. Impact of Financing BAT Options on Airport Debt Service 

Coverage Ratio – Single Airport Owners 

[172 airports (weighted)]

Option Incur 

costs [a] Not analyzed [a]

Owners with pre-regulatory DSCR > 

1.25 & post-regulatory DSCR < 1.25 

100% Cost Pass 

Through 

0% Cost Pass 

Through 

1 172 59 1 2 

2 [b] 172 59 2 3 

[a] Of 198 airports (weighted), each of the 172 was estimated to be both subject to BAT 

and the only airport controlled by its ownership. These columns represent the number of 

those 172 airports projected to incur costs under each option, and of those airports 

incurring costs, the number that cannot be analyzed due to lack of sufficient data. 

[b] Selected option. 

Table VIII–4. Impact of Financing BAT Options on Airport Debt Service Coverage Ratio 

– Multi Airport Owners 

[9 airport authorities owning 21 in-scope airports (unweighted) [a]]

Option 

Incur costs [b] Not analyzed [b]

Owners with preregulatory DSCR > 1.25 

& post-regulatory 

DSCR < 1.25 

Owners Airports Owners Airports 

100% Cost 

Pass 

Through 

0% Cost 

Pass 

Through 

1 9 21 1 5 0 0 

2 [c] 9 21 1 5 0 0 

[a] Some airports that are part of a multi-airport system have a sample weight greater than one; 

because airports were not sampled based on ownership patterns it is not appropriate to use the 

sample weight in this analysis; the results cannot be extrapolated to represent any airports and 

their ownership patterns other than themselves. 

[b] EPA found 9 distinct airport authorities owning 21 airports that were determined to be 

subject to BAT. These columns represent the number of airport owners and the number of 

airports they owned that are projected to incur costs under each option, and of those owners and 

airports incurring costs, the number that cannot be analyzed due to lack of sufficient data. 

[c] Selected option. 
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The DSCR analysis projects that two airports (of 59 analyzable airports) owned by single 

airport authorities, and no airports owned by multi-airport authorities (eight authorities owning 

16 airports subject to BAT), are at risk for default on their debt assuming 100 percent cost passthrough from airports to airlines. One additional airport is at risk for default assuming zero 

compliance costs are passed through from airports to airlines. Therefore EPA determined that 

this analysis also demonstrates that the rule is economically achievable. 

Moreover, EPA’s analysis likely overestimates the impact of the rule on airports’ ability 

to service debt. Of the two airports projected to be at risk of default under the 100 percent cost 

pass-through assumption, one completed installation of a deicing pad after the survey was 

submitted, and therefore, in reality, would incur significantly lower costs than the projected 

compliance costs. The second airport result may be an artifact of how that airport’s rates and 

charges are calculated: the airport’s 2004 DSCR was reported as exactly 1.25, and therefore, 

even though its projected annualized compliance costs are less than $10,000, the model predicts 

it is in danger of default. However, we judge it unlikely that an airport with 11 million passenger 

enplanements, operating revenues exceeding $80 million, and long-term bond ratings of “A” 

from Standard and Poor’s and Fitch Ratings, and “A2” from Moody’s Investor Services in 2004 

will default on its debt because of $10,000 in annualized compliance costs. 

Finally, an airport will not necessarily default on its debt should the airport’s postregulatory DSCR as measured in this analysis fall below the 1.25 threshold. Rather, this should 

be taken as an indication that the airport will potentially be in serious financial distress if it issues 

additional debt but does nothing to strengthen its financial condition. This is essentially a 

warning sign that the airport must undertake action to avoid default: rates and charges could be 

raised by a larger amount, debt might be restructured, and airports may have opportunities to pay 
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for capital expenditures without incurring debt (e.g., “pay-as-you-go” funded through rates and 

charges or passenger facility charges (PFC)). 

c. Impacts to Alaska’s Rural Aviation System 

Five airports operated by the State of Alaska could not be analyzed using the revenue test 

or the DSCR as presented above. These airports are part of Alaska’s Rural Aviation System 

(RAS) which is not a self-supporting system; Alaska has determined these airports must remain 

open despite financial loses to provide access to otherwise isolated rural communities. EPA 

evaluated economic impacts to these airports separately, as described below. 

Alaska operates two airport systems. The Alaska International Airport System (Ted 

Stevens Anchorage International Airport and Fairbanks International Airport) is a major 

enterprise fund of the State of Alaska, and considered to be self-sufficient; in short, the Alaska 

International Airport System operates in the same manner as most other multi-airport authorities 

in the United States. Alaska’s second system, the RAS, consists of 256 rural airports, is not a 

self-sufficient government unit, and loses money every year. EPA determined that five RAS 

airports would be subject to BAT requirements (Bethel, Ketchikan International, Sitka Rocky 

Gutierrez, Nome, and Ralph Wien Memorial). Due to the nature of transportation in Alaska, it is 

vital that these airports remain in operation despite not being profitable; approximately 82 

percent of Alaskan communities are not served by roads, and these communities rarely have a 

practical alternative to air transportation for access (DOT website convert to DCN XXXX). 

According to the Alaska Department of Transportation and Public Facilities (DOT&PF), RAS 

airports “are funded through a combination of user fees, state, local, or tribal funds, and federal 

funds.” However, the rural airports have very limited opportunities for generating revenue; in 

2004 revenues from airport users, concessions, and leasing of airport property comprised less 
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than 17 percent of the cost of operating the system (Maggard, 2008 [convert to DCN XXXX]). 

The system is largely reliant on state subsidies to pay O&M costs at these airports. Therefore 

EPA separately evaluated impacts to the RAS. 

EPA estimated compliance costs for the five RAS airports subject to BAT. EPA used the 

estimated yearly contribution of $23 to $24 million by the State of Alaska to cover the operating 

costs of the RAS (DCN AD05081) as a proxy for RAS operating revenues for the purpose of 

measuring economic impacts. This is an underestimate of RAS revenues because it does not 

account for the unknown revenue stream from other sources. Under the selected BAT option in 

the final rule, projected compliance costs for the five RAS airports together total $69,000, which 

compose 2.94 percent of the State’s contribution to airport operations. EPA therefore 

determined that because compliance costs to the RAS compose less than 3 percent of the 

system’s revenues, the rule is economically achievable to the RAS. 

Based on all of the above and as further documented in the record, EPA has determined 

that the final rule is economically achievable for airports. 

2. Results of Co-permittee Airline Impact Analysis 

EPA determined that 27 airports subject to BAT and incurring costs listed 75 individual 

airlines as co-permittees. Forty-nine of these co-permittee airlines were U.S.-flagged, while the 

remaining 26 were foreign-owned. On average, each of the 49 U.S.-flagged air carriers was a copermittee at 5 airports, with a range of co-permitting of between 1 to 21 airports. Under an 

assumption of a 50:50 split of compliance costs between airports and co-permittee airlines, these 

49 carriers would incur $18.8 million in annualized compliance costs, and the 26 foreign-flag 

carriers would incur $0.7 million. 
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Forty-six of the 49 U.S. co-permittee airlines have financial data available. Twenty-three 

co-permittees have positive baseline operating profits, and 21 have positive baseline net income, 

and therefore are eligible to be analyzed using these metrics. EPA projected that none of these 

airlines will incur costs exceeding 3 percent of operating profit or net income under either option 

1 or option 2. This is well short of the 100 percent threshold that would indicate a definitive 

closure. Furthermore, none of the 46 airlines were projected to incur compliance costs exceeding 

0.25 percent of operating revenues under option 1, and only 1 airline was projected to incur costs 

exceeding costs 0.25 percent of revenues under option 2. To put this in context of other costs 

borne by the airlines, EPA’s analysis shows that co-permittee airlines will incur costs from this 

rule that create on average 0.029 percent of operating revenues; while these airlines on average 

spend 26 times that amount on advertising (0.76 percent of operating revenues), and 35 times 

that amount on food (1.02 percent of operating revenues). Therefore EPA judged these airline 

co-permittees are not significantly impacted by the rule. 

Finally, to the extent that 50 percent of airport compliance costs are shared with copermittee airlines, impacts to airports are reduced as measured by the ratio of compliance costs to 

operating revenue. EPA projects 5 airports incur costs exceeding 3 percent of revenues under the 

promulgated option using the assumptions of the co-permittee airline analysis. Assuming no 

costs are shared with co-permittee airlines, EPA projected 9 airports incur costs exceeding 3 

percent of revenues under this option. 

3. Economic Achievability 

Based on the analyses presented above, EPA has determined that both Option 1 and 

Option 2 are economically achievable. EPA finds that the promulgated option is economically 
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achievable both when airports are assumed to incur 100 percent of compliance costs, and when 

airports and their applicable airline co-permittees are assumed to share compliance costs. 

Under previous rulemaking efforts that directly impose compliance costs on government 

agencies, EPA used the revenue test to evaluate impacts to these agencies; when projected 

compliance costs exceed 3 percent of operating revenues, the rule is judged to be unaffordable 

for a facility. As shown in Table VIII–2, only 9 airports, which are less than 5 percent of the 

airports subject to BAT, are projected to incur costs exceeding 3 percent of operating revenue 

when airports are assumed to incur 100 percent of compliance costs. EPA used several 

conservative assumptions in evaluating impacts to airports: costs were annualized using a real 7 

percent interest rate, which is significantly higher than airports typically pay for debt financing. 

At the 7 percent real interest rate, EPA demonstrated that airports’ ability to service debt would 

not, in general, be negatively affected by the rule. EPA also did not take into account airports’ 

ability to access other funding for capital expenditure, such as AIP grants or PFCs. Also, EPA 

performed its analysis of airport impacts without distributing any costs to co-permittee airlines. 

As such, the estimates of impacts at airports with co-permittees may be overstated. 

With respect to airlines that are NPDES co-permittees, none of these airlines are shown 

to incur a demonstrable impact under either option on three airline income measures: operating 

revenue, operating profit, or net income. Therefore, EPA finds the costs to be economically 

achievable for co-permittee airlines for either of the options considered for today’s final rule. 

Finally, EPA also assumed compliance costs would not be passed through to airlines 

and/or their passengers in the form of higher rates and charges. (As explained above, EPA did 

assume costs would be shared by co-permittee airlines.) This is a conservative assumption and 

EPA believes that airports and, ultimately, airlines will use some or all of the above to reduce the 
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cost and impact of the rule, which is further support for EPA’s conclusion that today’s final rule 

is economically achievable. 

E. Economic Impacts for New Sources 

EPA has determined that the NSPS in the final rule would not impose a barrier to entry. 

Although few greenfield airports (airports built on undeveloped land or land not previously used 

for aviation) have been developed with deicing pads, EPA obtained data for Denver International 

Airport, which incorporated deicing pads. Information from Denver demonstrates that the CDPs 

comprised 4 percent of the cost of building a new airport, and did not pose a barrier to entry 

(DCN XXXX). 

However, the building of major greenfield airports has become a relatively rare 

occurrence. Denver International opened in 1995, but new, major airports built prior to Denver 

predate it by 20 or more years: Dallas-Fort Worth, which opened in 1973, and George Bush 

International in Houston, Texas and Washington Dulles, which opened in the 1960s. Conversion 

of ex-military airports appears to be a much more common source of sites for cities seeking to 

increase air transportation access (e.g., Orlando International). EPA reviewed FAA’s National 

Plan of Integrated Airport Systems (NPIAS) reports published between 2002 and 2010, and 

found that the development of any new commercial service airports is relatively rare, but a 

smaller commercial service greenfield airport is more likely to be built than a major one. In 

2002 FAA expected 125 airports to open within the next five years, none of which were 

commercial service airports. Since then, a new commercial service airport in Panama City, FL 

opened in May 2010, and St. George, UT opened in January, 2011. The opening of a third 

commercial service airport in Peotone, IL that was expected by 2015 currently appears to be on 

hold (Chicago-Tribune, 2010/DCN XXXX). Cities such as Bowling Green, KY, Hazleton, PA, 
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and Las Vegas, NV have been performing needs assessment and feasibility studies since before 

2002, but as of 2010 no solid plans appear to have emerged. 

Therefore, EPA wanted to examine a broader set of airport characteristics to account for 

new smaller commercial airports that might be subject to new source requirements. Based on 

incomplete data published in the NPIAS, EPA assumes that the St. George airport, with a 

planned service level of 55,000 annual enplanements, cost a minimum of $70 million. The 

Panama City airport, with a planned service level of 225,000 annual enplanements, appears to 

have cost a nominal $200 million in the same period. Because eligibility for the ELG is partly 

based on non-propeller driven aircraft departures, EPA estimated departures for these two 

airports based on expected annual enplanements. Among the 198 existing airports subject to 

BAT requirements, only 14 in the lower 48 states have fewer than 100,000 annual enplanements, 

and only 6 have fewer than 60,000 annual enplanements. Thus, EPA believes an airport like St. 

George might be too small to be subject to the requirements of this effluent guideline. However, 

a new airport the size of the Panama City airport might be subject to new source requirements. 

Due to its location, EPA does not expect that the Panama City airport itself will be subject to 

NSPS requirements. However, this airport is the only airport EPA found with data available on 

construction costs, and is of sufficient size that it might be subject to the ELG were it located 

further north. Therefore, EPA used Panama City’s cost data to represent a new, relatively small 

airport that is subject to NSPS. 

Based on CDPs constructed at existing airports, EPA estimated the average capital cost of 

constructing a CDP of appropriate size to meet the airport's operating requirements as total CDP 

capital cost divided by average annual departures. Thus, the average capital cost of a CDP is 

$515 per average annual departure (DCN XXXX). In addition, EPA estimated annual departures 
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at Panama City; existing commercial service airports with annual enplanements between 200,000 

and 300,000 average about 32.3 passengers per departure, thus EPA expects Panama City will 

average somewhat less than 7,000 departures per year. Therefore, EPA estimates that should an 

airport the size of Panama City need to build a CDP, then the capital cost of that pad will be 

about $3.6 million, or about 1.8 percent of the initial cost of the airport. Furthermore, CDPs 

integrated into airport traffic patterns from the time of construction can be planned to minimize 

impacts on flight operations. Therefore, with CDPs expected to cost from 1.8 percent to 4 

percent of the cost of building a new airport, EPA has determined that the NSPS in the final rule 

would not impose a barrier to entry. 

F. Cost and Pollutant Reduction Comparison 

Today’s final rule is expected to reduce COD and ammonia loads by 33 million pounds at 

an annualized cost of $78.0 million, for a cost of $2.37 per pound of pollutant removed. 

Table VIII-5. Pollutant Removals, Costs and Cost-Reasonableness of BAT Options 

for Airports that Deice (weighted) 

Option 

Total pollutant 

Removals 

(million lb) 

Total annualized costs 

(2006 $ mil.) 

Cost/lb pollutant 

removed 

1 30.2 $49.4 $1.64 

2 [a] 33.0 $78.4 $2.37 

[a] Selected option. 

EPA has reviewed the relative cost per pound of pollutants removed in previous effluent 

guidelines and has found that the cost per pound presented in today’s final Airport Deicing rule 

is similar to or less expensive than many guidelines promulgated to date including: Aluminum 

Forming (40 CFR part 467), $2.42/lb; Landfills (40 CFR part 445), $15.00/lb; and Waste 

Combustors (40 CFR part 444), $38.83/lb. 
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G. Small Business Analysis 

The Regulatory Flexibility Act (RFA), as amended by the Small Business Regulatory 

Enforcement Fairness Act of 1996 (SBREFA; hereinafter referred to as RFA), acknowledges that 

small entities have limited resources, and makes it the responsibility of regulating federal 

agencies to avoid burdening such entities unnecessarily. The ultimate goal of RFA is to ensure 

that small entities do not incur disproportionate adverse economic impacts as a result of a 

regulation. The first step in this process is to determine the number and type of small entities 

potentially affected by the regulation. 

The RFA (5 U.S.C. 601) defines three types of small entities: small business, small notfor-profit organization, and small governmental jurisdictions. Airport ownership is composed of 

states, county, city governments, and single and multi-purpose port authorities. Single and 

multi-purpose port authorities are quasi-governmental agencies created by legislation to maintain 

and operate airports, shipping ports, and other government-owned facilities such as bridges. 

The RFA defines a small government entity as governments of cities, counties, towns, 

townships, villages, school districts, or special districts, with a population of less than 50,000. 

After matching each airport-owning governmental entity with its population, EPA estimates that: 

 72 airports are owned by small government entities 

 20 airports owned by small government entities are subject to BAT requirements in 

today’s final rule. 

Although many Alaskan airports are relatively small when measured by service level, most of 

these airports are owned by the State of Alaska and therefore are not considered small for the 

purposes of the RFA; 10 of the 11 surveyed Alaskan airports are not small by this standard. 
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One of the 20 BAT airports owned by small government entities is expected to incur total 

annualized compliance costs exceeding three percent of airport operating revenues. 

Table VIII–6. Financial Impacts of BAT Options on Small Airports that Deice [a]

[2006 $ millions – 20 airports (weighted)] 

Option 

Total 

annualized 

costs 

Number of airports with ratio of annualized compliance 

costs to operating revenues of: 

Less than 

1% 

Between 1% 

and 3% 

Greater than 

3% 

Not 

analyzed [b]

1 $0.34 19 0 1 0 

2 [c] $0.34 19 0 1 0 

[a] An airport is considered small if the governmental entity that owns the airport serves a 

region with less than 50,000 people. 

[b]Airports incurred compliance costs but financial impacts could not be analyzed due to lack 

of airport revenue data. 

[c] Selected option. 

EPA found 18 airlines that are co-permittees at BAT airports are small by SBA standards; 

16 of these airlines had available financial data. None of the 16 small co-permittee airlines were 

projected to incur compliance costs exceeding 1 percent of operating revenues under either 

option 1 or option 2; 15 of the 16 are projected to incur costs that are less than 0.25 percent of 

operating revenues, and the 16th airline is projected to incur costs less than 0. 5 percent of 

operating revenues under option 2. When comparing compliance costs with operating profits 

and net income, 8 small airlines had positive baseline operating profits and net income, and none 

are projected to incur costs exceeding 3 percent of either measure under option 1 or option 2. 

Again, these are well short of the 100 percent threshold that would indicate a definitive closure. 

One airport with airline co-permittees on its NPDES permit is small by SBA standards. 

This airport’s projected compliance costs exceed 3 percent of airport revenue if it does not share 

compliance costs with its co-permittee airlines. Its costs do not exceed 3 percent of revenue if it 

does share compliance costs with its co-permittee airlines. 
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EPA concludes that small entities are not disproportionately affected by this effluent 

limitations guideline. Only a fraction of in-scope airports are small by SBA standards, and only 

one of those airports is projected to incur costs exceeding 3 percent of operating revenues. 

Furthermore, this airport is not projected to exceed that threshold if 50 percent of its compliance 

costs are shared with co-permittee airlines. EPA also concludes that small airlines are not 

disproportionately affected by the rule. Airlines are only subject to the rule if they are copermittees on an airport's NPDES permit. Eighteen co-permittee airlines are small by SBA 

standards, 16 of which have financial data available. As described above, analysis of these 

airlines shows that under the assumption of 50:50 cost sharing with affected airports, none come 

close to a threshold that indicates a significant impact to their financial situation. 

IX. Environmental Assessment 

A. Environmental Impacts 

 EPA has evaluated environmental impacts associated with the discharge of wastewater 

from airport deicing activities (Environmental Impact and Benefit Assessment for Final Effluent 

Guidelines and Standards for the Airport Deicing Category (EIB)). As discussed in Section 

VII.B., deicing wastewater discharges can increase the loadings of multiple pollutants to 

receiving surface waters. 

 The most widely recognized pollutant from deicing activity is oxygen-demanding 

material, measured as either COD or BOD5. All primary ingredients in both aircraft and airfield 

deicers exert oxygen demand. Propylene glycol and ethylene glycol are the primary ingredients 

in aircraft deicers. Acetate salts, formate salts, propylene glycol, ethylene glycol and urea are the 

primary ingredients in airfield deicers. Propylene glycol and ethylene glycol, in particular, exert 
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extremely high levels of oxygen demand when they decay in the environment. Acetates, 

formates, and urea exert lower, though still significant, levels of oxygen demand. 

 Acetate or formate salts, the primary ingredients in many airfield deicers, also contain 

potassium or sodium. Potassium and sodium can raise overall salinity levels or cause ion 

imbalances in surface waters. Urea, another primary airfield deicer ingredient, decomposes in 

water to produce ammonia, a toxic compound, and nitrates, a nutrient pollutant that can increase 

the incidence of organism blooms in surface waters. 

 Aircraft and airfield deicers also contain additives in addition to the primary ingredients. 

These additives serve a variety of purposes such as reducing fluid surface tension, thickening, 

and fire and corrosion inhibition. Because deicer manufacturers consider the identity and 

quantity of additives in their formulations to be proprietary information, EPA was unable to 

obtain complete information on the nature and use of these additives. 

 EPA was able to obtain some limited information through various public sources, and 

identified several additives with toxic properties. These include nonylphenol ethoxylates, 

alcohol ethoxylates, triazoles, polyacrylic acid and others. Although toxic, these additives 

directly influence the effectiveness and safety of deicing and anti-icing formulations and are 

therefore essential components. Because deicer formulations change periodically, some of the 

additives EPA identified may not be present in current formulations. Deicing fluid 

manufacturers are also investigating ways to formulate deicing and anti-icing compounds with 

the use of less toxic, or non-toxic, additives 

Airports in the United States discharge deicing wastewater to a wide variety of water 

body types including streams, rivers, lakes and estuaries. Many airports discharge deicing 

wastewater to small streams with limited waste dilution and assimilation capacities. Impacts 
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from deicing wastewater discharges have been documented in a variety of surface waters 

adjacent to or downstream of a number of airports in the United States. Some locations 

experienced acute impact events, whereas other locations have chronically degraded conditions. 

Observed impacts to surface waters include both physical and biological impacts. Some surface 

waters have been listed as impaired under section 303(d) of the CWA because they do not meet 

applicable state water quality standards. Physical impacts include elevated levels of glycol, 

salinity, ammonia, and other pollutants; depressed oxygen levels; foaming; noxious odors; and 

discoloration. Biological impacts include reduced organism abundance; fish kills; modified 

community composition; and reduced species diversity. 

 Deicing wastewater discharges have impaired both aquatic community health and human 

uses of water resources. Available documentation indicates multiple cases of hypoxic conditions 

and severe reduction in aquatic organism levels in surface waters downstream of deicing 

wastewater discharge locations. Documented human use impacts include contamination of 

surface drinking water sources, contamination of groundwater drinking water sources, degraded 

surface water aesthetics due to noxious odors and discolored water in residential areas and 

parklands, and degradation of fisheries. 

B. Environmental Benefits 

 EPA has evaluated environmental benefits associated with today’s final rule to reduce the 

discharge of pollutants from airport deicing activities. This assessment is described in detail in 

the EIB. The final rule BAT requirement is expected to decrease COD discharges associated 

with airport deicing activities by approximately 28.6 million pounds per year. The BAT 

requirement is also estimated to reduce ammonia discharges by 4.4 million pounds. The rule 

will also reduce the loadings of toxic additives in aircraft deicer formulations to the environment. 
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 The decline in pollutant loadings will reduce environmental impacts to surface waters 

adjacent to and downstream of these airports. A variety of surface waters have improved in 

quality after reductions in deicing pollutant loadings. Documented improvements have included 

abatement of noxious odors, decline in fish kill frequency, and partial recovery of community 

species diversity, and organism abundance in small water bodies. 

 Today’s final rule will decrease pollutant loadings to multiple surface waters currently 

listed as impaired under CWA section 303(d). The rule will also reduce pollutant loadings to 

surface drinking water intakes, parks, and residential areas downstream of airports. Groundwater 

aquifers will also benefit. See the EIB for additional details. 

X. Non-Water Quality Environmental Impacts 

 Sections 304(b) and 306 of the Clean Water Act require EPA to consider non-waterquality environmental impacts (including energy requirements) associated with effluent 

limitations guidelines and standards. To comply with these requirements, EPA considered the 

potential impact of the collection and treatment technologies on energy consumption, air 

emissions, and solid waste generation. While EPA prepared formal analyses only for 

technologies associated with today’s BAT requirements, given the similarities between the two 

regulatory options evaluated today, it anticipates that Option 1 would produce similarly minimal 

non-water quality impacts. For a more in-depth analysis of these non-water quality impacts, see 

the Technical Development Document. 

A. Energy Requirements 

 Net energy consumption considers electrical requirements for pumping ADFcontaminated stormwater from collection areas to storage, electrical requirements for operating 
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the anaerobic fluidized bed (AFB) bioreactors, and fuel requirements for glycol collection 

vehicles (GCVs). 

 EPA estimates that 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 also developed a relationship between electrical use and chemical oxygen 

demand (COD) removal by the AFB bioreactors based on information provided by Albany 

International (ALB) airport. Using the information from ALB, EPA estimated the electrical 

requirement for COD removal as approximately 1.3 kWh/lb COD removed. Using this unit rate, 

EPA estimated total electrical requirements to remove COD for the final rule 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.2

 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, to be 354,500 gallons per year. 

 EPA compared incremental diesel fuel use by GCVs as a result of the rule to diesel fuel 

use on a national basis. Approximately 25.4 million gallons per day of No. 2 diesel fuel was 

consumed in the United States in 2005. The diesel fuel requirement associated with this rule is 

less than 0.004 percent of the annual amount of diesel fuel consumed. 

 

2

 This diesel fuel price was the average reported by the Energy Information Administration for the 2004-05 winter 

season, the same period that EPA is analyzing for airport deicing activity. 
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 Additionally, as EPA assumes that aircraft operations will not be delayed as a result of 

today’s rule and that deicing will occur at the gates, there is no increase in jet fuel consumption 

associated with today’s rule. 

B. Air Emissions 

 Additional air emissions as a result of the rule could 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. As EPA assumed no increase in jet 

fuel consumption, there is no increase in emissions from aircraft operations associated with 

today’s regulation. 

1. Emissions from GCV Collection 

 As discussed in Section XI.A above, 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 the 

internal combustion engines on GCVs, EPA used published emission factors for internal 

combustion engines. The Agency selected emission factors for gasoline and diesel industrial 

engines because EPA assumed this class to be a more representative population of engines. 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. The calculated annual emissions indicate that an additional 4,070 tons per year of 

carbon dioxide (CO2) will be emitted from GCVs combusting additional diesel fuel to comply 

with the rule. Carbon dioxide is the primary greenhouse gas attributed to climate change, and the 

4,070 additional tons per year that would be associated with the rule is very small relative to 

other sources. For example, in 2006, industrial facilities combusting fossil fuels emitted 948 
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million tons of CO2 equivalents. An additional 4,070 tons per year from GCVs is less than a 

0.0004 percent increase in the overall CO2 emissions from all industrial sources. 

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 for treatment of ADF-contaminated stormwater are expected to burn a portion of the gas in 

on-site boilers in order 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 

greenhouse gas. EPA calculates a maximum 3,730 additional tons per year of CO2 generation 

for 40 percent ADF collection, which 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 3,730 tons per year of carbon dioxide from AFB treatment is less than 0.0004 

percent of the annual industrial carbon dioxide emissions nationwide. 

C. Solid Waste Generation 

 AFB bioreactors will generate sludge that will require disposal, probably in an off-site 

landfill. To estimate annual sludge generation by the AFB bioreactors that may be installed at 

airports to treat ADF-contaminated stormwater, EPA first estimated the potential COD removal 

for the collection and treatment scenarios and then applied published anaerobic biomass yield 

information to estimate 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 
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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. 

 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 most 

conservative biomass generation estimate with its national biosolids estimates for all domestic 

wastewater treatment plants throughout the United States. Approximately 8.2 million dry tons of 

biosolids were produced in 2010. EPA estimates that AFB bioreactors treating ADFcontaminated stormwater will increase biosolids generation in the United States by 

approximately 271 dry tons/year or less than 0.003 percent of dry ton biosolids produced in the 

U.S. in 2010. 

 Based on this evaluation of non-water quality impacts, EPA concludes there are no nonwater quality impacts associated with today’s final rule. 

XI. Regulatory Implementation 

A. Relation of ELGs to NPDES Permits 

 Effluent guidelines act as a primary mechanism to control the discharge of pollutants to 

waters of the U.S. Today’s final rule will be applied to airports through incorporation in 

individual or general NPDES permits issued by EPA or authorized states under section 402 of 

the Act. 

 The Agency has developed the limitations for this final rule to cover the discharge of 

pollutants from this point source category. In addition, if state water quality standards or other 

provisions of state or federal law require limits on pollutants not covered by this regulation (or 
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require more stringent limits or standards on covered pollutants to achieve compliance), the 

permit authority must apply those effluent limitations or standards. 

 For individual permits, ELG provisions are typically incorporated when those permits are 

renewed, although permit authorities may require modification upon promulgation. EPA will 

revise its Multi-Sector General Permit to include the airport deicing provisions when the permit 

is renewed, and authorized states will proceed likewise with their respective general permits. 

B. Applicability Date 

 The general applicability date for today’s final rule is [insert date that is 30 days after the 

date of publication in the Federal Register]. However, in response to comments received, EPA 

has added a provision at § 449.1(b) to extend the date of applicability of the ADF collection and 

discharge requirements for existing airports to provide an additional three years to comply, in 

order to arrange for financing and/or construction of capital improvements. Airports that have 

permit renewal dates more than three years from the general applicability date do not receive this 

extension. 

C. Demonstrating Compliance with the ADF Collection Requirement 

 The ADF collection requirement differs from traditional end-of-pipe effluent limitations 

with regard to demonstrating compliance. Compliance with the collection requirement may not 

always be determined through end-of-pipe sampling and analysis. Additionally, the amount of 

ADF available for collection can vary depending on the weather and icing conditions at the time 

of application. As in the proposed rule, today’s final rule provides three procedures for selection 

by the permittee, for demonstrating compliance with the ADF collection requirement. 

 To utilize the first procedure, at §449.20 (a)(1) for BAT and §449.20 (b) for NSPS, a 

permittee certifies to the permitting authority that it is operating its collection system in 
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accordance with specifications for the applicable technology. The specifications describe design 

and operating practices for the technologies. As long as these technologies are operated and 

maintained as required, the permittee will be deemed in compliance with the associated 

collection rate. The only reporting requirement for this procedure would be for the permitted 

facilities to certify to the permit authority that it is operating according to the specifications. 

 Since it is not practical for EPA to provide operating specifications for all potential 

collection technologies, the procedure at §449.20 (a)(2) and (b)(2) allows an airport with an 

individual permit to propose performing ADF collection with a technology other than those 

described in the regulations. The permit authority may allow, on a case-by-case basis, an 

alternative ADF collection technology as the manner in which the permittee must demonstrate 

compliance with its collection requirement. The Director may also allow alternate operating 

parameters for one of the technologies listed elsewhere in § 449.20, as requested and 

demonstrated by the permittee. For example, an airport may operate a plug and pump system 

and demonstrate that it collects 40 percent of available ADF, without necessarily having all 

flights deiced in the designated collection area(s). Another example would be an airport that 

utilizes a technology other than plug and pump, with clearly detailed technical specifications and 

data demonstrating it would collect 40 percent of the available ADF. A third example would be 

an airport that is unable or unwilling to utilize a standard set of collection technologies and 

operating procedures, and instead elects to demonstrate compliance with the ADF collection 

requirement by regular monitoring of applied and collected ADF. EPA has not published a 

specific monitoring methodology for a permittee to demonstrate its compliance with the 

collection requirement, but expects that such a demonstration would involve some type of massbalance analysis. This procedure would be developed by the permittee, prior to the permitting 
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authority proposing the permit, so that the method would be subject to public comments prior to 

incorporation into the permit. As long as the permittee is able to demonstrate to the permit 

authority’s satisfaction that the specified technology is designed to achieve the collection 

requirement as set forth in § 449.10(a)(1) or § 449.11(a)(1), the only reporting requirement for 

this provision is for the permittee to certify that it is operating and maintaining its permitted 

technology as required in its permit. 

 Several pollution prevention (P2) approaches and technologies are described above in 

Section V.D.3. Although EPA did not identify any of these technologies as a basis for BAT or 

NSPS, these technologies may be effective at reducing available ADF. Permittees using a P2 

technology for aircraft deicing may request a credit to be applied to the ADF collection 

requirement. Under § 449.20 (a)(2)(ii) and § 449.20 (b)(2)(ii), a permittee may request a credit 

by providing documentation on volumes of available ADF that would be generated in absence of 

the pollution prevention approach and the volumes of available ADF reduced through the use of 

P2. Once the permit authority determines that the reductions values are demonstrated, it will 

adjust the ADF collection requirement by subtracting the P2 available ADF reductions from the 

original ADF collection requirement. For example, an existing airport calculated to have 

1,000,000 gallons of available ADF would ordinarily be required to demonstrate 40 percent 

collection (or 400,000 gallons). If the permittee can demonstrate that its P2 activities reduce the 

amount of available ADF to 800,000 gallons, then it would only be required to demonstrate 

collection of 200,000 additional gallons. 

 Permittees may request use of alternative procedures at the time of permit 

application/renewal or throughout the permit term. A request submitted during the permit term 
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would be a proposed permit modification, subject to the requirements at 40 CFR 122.62 and 40 

CFR part 124. 

D. Permit Application Requirements 

 In order for the permit authority to determine whether an existing discharger is subject to 

the ADF collection and associated discharge requirements in today’s final rule, the permittee 

must report its prior ADF usage when applying for permit renewal or submitting an NOI under a 

general permit. The permittee may also simply report that it met or exceeded the annual 

threshold of 60,000 gallons of normalized ADF usage. See § 122.21(s)(1). 

E. COD Effluent Monitoring for Direct Dischargers 

 Direct dischargers are required by the final rule to sample and analyze the discharges 

from their treatment system for COD prior to any dilution or co-mingling with other non-deicing 

waters. The sampling frequency, analytical method and reporting procedures are determined by 

the permit authority. Permittees must follow the sampling protocol specified in Appendix A of 

Part 449. 

F. Alternative Compliance Option for Pavement Deicers Containing Urea 

 While EPA expects that most airports will choose product substitution to meet the 

pavement deicer requirement in § 449.10(b) or § 449.11(b), airports may continue to use 

pavement deicers containing urea if they meet the alternative effluent limitation. An airport that 

chooses this alternative is required to perform an analysis for ammonia in airfield pavement 

discharges at all locations where pavement deicing with deicers containing urea is occurring and 

must achieve the numeric limitations for ammonia prior to any dilution or commingling with 

other non-deicing discharges. The sampling frequency, analytical method and reporting 

procedures are determined by the permit authority. 
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G. Best Management Practices 

 Sections 304(e), 308(a), 402(a), and 501(a) of the CWA authorize the Administrator to 

prescribe BMPs as part of effluent guidelines and standards or as part of a permit. EPA's BMP 

regulations are found at 40 CFR 122.44(k). Section 304(e) of the CWA authorizes EPA to 

include BMPs in effluent limitation guidelines for certain toxic or hazardous pollutants to control 

"plant site runoff, spillage or leaks, sludge or waste disposal, and drainage from raw material 

storage." CWA sec. 402(a)(1) and NPDES regulations (40 CFR 122.44(k)) also provide for best 

management practices to control or abate the discharge of pollutants when numeric limitations 

and standards are infeasible. In addition, CWA sec. 402(a)(2), read in concert with CWA sec. 

501(a), authorizes EPA to prescribe as wide a range of permit conditions as the Administrator 

deems appropriate in order to ensure compliance with applicable effluent limitations and 

standards and such other requirements as the Administrator deems appropriate. 

 There are no BMPs specified in today’s final rule. However, existing NPDES permits for 

airports include BMP requirements, and some permits may have included, as required BMPs, the 

technologies that EPA has identified as a basis for BAT or NSPS in today’s rule. Other BMPs 

included in airport permits include dikes, curbs, and other control measures to contain leaks and 

spills as part of good "housekeeping" practices. On a facility-by-facility basis a permit writer 

may choose to incorporate BMPs into the permit. See the TDD for a detailed discussion of 

pollution prevention and best management practices used by airports and airlines. 

H. Upset and Bypass Provisions 

 A “bypass” is an intentional diversion of the streams from any portion of a treatment 

facility. An “upset” is an exceptional incident in which there is unintentional and temporary 

noncompliance with technology-based permit effluent limitations because of factors beyond the 
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reasonable control of the permittee. EPA's regulations concerning bypasses and upsets for direct 

dischargers are set forth at 40 CFR 122.41(m) and (n). 

I. Variances and Modifications 

 The CWA requires application of effluent limitations established pursuant to sec. 301 to 

all direct dischargers. However, the statute provides for the modification of these national 

requirements in a limited number of circumstances. Moreover, the Agency has established 

administrative mechanisms to provide an opportunity for relief from the application of the 

national effluent limitation guidelines for categories of existing sources for toxic, conventional, 

and nonconventional pollutants. 

1. Fundamentally Different Factors Variance 

 EPA, with the concurrence of the State, may develop effluent limitations or standards 

different from the otherwise applicable requirements if an individual discharger is fundamentally 

different with respect to factors considered in establishing the limitation of standards applicable 

to the individual discharger. Such a modification is known as a "fundamentally different factors" 

(FDF) variance. EPA, in its initial implementation of the effluent guidelines program, provided 

for the FDF modifications in regulations. These were variances from the BCT effluent 

limitations, BAT limitations for toxic and nonconventional pollutants and BPT limitations for 

conventional pollutants for direct dischargers. FDF variances for toxic pollutants were 

challenged judicially and ultimately sustained by the Supreme Court. (Chemical Manufacturers 

Association v. Natural Resources Defense Council, 479 U.S. 116 (1985)). 

 Subsequently, in the Water Quality Act of 1987, Congress added new CWA section 

301(n). This provision explicitly authorizes modifications of the otherwise applicable BAT 

effluent limitations, if a discharger is fundamentally different with respect to the factors specified 
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in CWA section 304 (other than costs) from those considered by EPA in establishing the effluent 

limitations. CWA section 301(n) also defined the conditions under which EPA may establish 

alternative requirements. Under sec. 301(n), an application for approval of a FDF variance must 

be based solely on (1) information submitted during rulemaking raising the factors that are 

fundamentally different or (2) information the applicant did not have an opportunity to submit. 

The alternate limitation must be no less stringent than justified by the difference and must not 

result in markedly more adverse non-water quality environmental impacts than the national 

limitation. 

 EPA regulations at 40 CFR part 125, subpart D, authorizing the Regional Administrators 

to establish alternative limitations, further detail the substantive criteria used to evaluate FDF 

variance requests for direct dischargers. Thus, 40 CFR 125.31(d) identifies six factors (e.g., 

volume of process wastewater, age and size of a discharger's facility) that may be considered in 

determining if a discharger is fundamentally different. The Agency must determine whether, 

based on one or more of these factors, the discharger in question is fundamentally different from 

the dischargers and factors considered by EPA in developing the nationally applicable effluent 

guidelines. The regulation also lists four other factors (e.g., inability to install equipment within 

the time allowed or a discharger's ability to pay) that may not provide a basis for an FDF 

variance. In addition, under 40 CFR 125.31(b) (3), a request for limitations less stringent than 

the national limitation may be approved only if compliance with the national limitations would 

result in either (a) a removal cost wholly out of proportion to the removal cost considered during 

development of the national limitations, or (b) a non-water quality environmental impact 

(including energy requirements) fundamentally more adverse than the impact considered during 

development of the national limits. The legislative history of sec. 301(n) underscores the 
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necessity for the FDF variance applicant to establish eligibility for the variance. EPA's 

regulations at 40 CFR 125.32(b)(1) are explicit in imposing this burden upon the applicant. The 

applicant must show that the factors relating to the discharge controlled by the applicant's permit 

which are claimed to be fundamentally different are, in fact, fundamentally different from those 

factors considered by EPA in establishing the applicable guidelines. In practice, very few FDF 

variances have been granted for past ELGs. An FDF variance is not available to a new source 

subject to NSPS. 

2. Economic Variances 

 Section 301(c) of the CWA authorizes a variance from the otherwise applicable BAT 

effluent guidelines for nonconventional pollutants due to economic factors. The request for a 

variance from effluent limitations developed from BAT guidelines must normally be filed by the 

discharger during the public notice period for the draft permit. Other filing periods may apply, 

as specified in 40 CFR 122.21(m)(2). Specific guidance for this type of variance is provided in 

“Draft Guidance for Application and Review of Section 301(c) Variance Requests,” August 21, 

1984, available on EPA’s website at http://www.epa.gov/npdes/pubs/OWM0469.pdf. 

3. Water Quality Variances 

 Section 301(g) of the CWA authorizes a variance from BAT effluent guidelines for 

certain nonconventional pollutants due to localized environmental factors. These pollutants 

include ammonia, chlorine, color, iron, and total phenols. 

J. Information Resources 

 The Transportation Research Board (TRB), a division of the National Academies of 

Science, established a research panel to develop fact sheets on deicing practices to assist airports 

in reducing their deicing chemical usage and discharges. A report was prepared in 2009 under 
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TRB’s Airport Cooperative Research Program (ACRP), titled “Deicing Planning Guidelines and 

Practices for Stormwater Management Systems.” This report (DCN AD01191) and the fact 

sheets (DCN AD01192) are available in the docket for today’s rule. 

XII. Statutory and Executive Order Reviews 

A. Executive Order 12866: Regulatory Planning and Review and Executive Order 13563: 

Improving Regulation and Regulatory Review 

 EPA submitted this action to the Office of Management and Budget (OMB) for review 

under EO 12866 (58 FR 51735, October 4, 1993) and EO 13563 (76 FR 3821, January 21, 2011) 

and any changes made in response to OMB recommendations have been documented in the 

docket for this action. 

B. Paperwork Reduction Act 

 The information collection requirements in this rule [* Insert “have been” or “will be”] 

submitted for approval to the Office of Management and Budget (OMB) under the Paperwork 

Reduction Act, 44 U.S.C. 3501 et seq. The information collection requirements are not 

enforceable until OMB approves them. 

 Some of the reporting requirements in today’s rule are once per permit cycle or once per 

year, while others are continuous. Based on the reporting requirements in today’s rule, EPA is 

assessing the costs for permittees to: 

 report the amount of normalized ADF usage per year, once a permit cycle.

 Annually certify non-use of airfield pavement deicers containing urea. EPA 

estimates that the once-per-year cost is negligible.

 demonstrate compliance with BAT or NSPS requirements by: 
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o conducting and documenting annual inspections of the ADF collection 

system to demonstrate compliance with technical specifications set forth 

in today’s regulation,

o analyzing COD concentrations of effluent, and 

o conducting an assessment of their ADF collection percentage once per 

permit cycle. While this is not a requirement of the regulation, EPA 

anticipates that many permittees will opt to comply using alternate 

technologies or technologies with alternate technical specifications, and 

will likely need to assess the ADF collection rate at their airport in order 

to determine how much additional collection is required. As such, EPA is 

likely over estimating the costs associated with reporting requirements by 

assuming all airports will conduct such an assessment. 

EPA estimates it would take an annual average of 15,231 hours and $533,078 for 

permittees to collect and report the information required by the rule. This estimate is based on 

average labor rates obtained from EPA’s airport questionnaire 

EPA estimates it would take an average of 218 hours and $7,195 for permit authorities to 

review the information submitted in response to requirements in the rule as part of permit 

applications, renewals, and NOIs. EPA estimates that there would be no start-up or capital cost 

associated with the information described above. Burden is defined at 5 CFR 1320(b). 

 An agency may not conduct or sponsor, and a person is not required to respond to, a 

collection of information unless it displays a currently valid OMB control number. The OMB 

control numbers for EPA's regulations in 40 CFR are listed in 40 CFR part 9. In addition, EPA 

is amending the table in 40 CFR part 9 of currently approved OMB control numbers for various 
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regulations to list the regulatory citations for the information requirements contained in this final 

rule. 

C. Regulatory Flexibility Act 

 The Regulatory Flexibility Act (RFA) generally requires an agency to prepare a 

regulatory flexibility analysis of any rule subject to notice and comment rulemaking 

requirements under the Administrative Procedure Act or any other statute unless the agency 

certifies that the rule will not have a significant economic impact on a substantial number of 

small entities. Small entities include small businesses, small organizations, and small 

governmental jurisdictions. 

 For the purposes of assessing the impacts of today’s final rule on small entities, EPA 

determined that all airports expected to be subject to BAT requirements are owned by 

government entities. The RFA defines a small government entity as governments of cities, 

counties, towns, townships, villages, school districts, or special districts, with a population of 

less than 50,000 (5 U.S.C. 601 (5)). After considering the economic impact of today’s final rule 

on small entities, including consideration of alternative regulatory approaches, I certify that this 

action will not have significant economic impact on a substantial number of small entities. After 

matching each airport-owning governmental entity with its population, EPA estimates that 20 of 

198 airports subject to BAT, or 10 percent, are owned by small government entities. EPA 

projected impacts on these small airports using the revenue test described in Section VIII.C.2.a. 

EPA found that 1 of the 20 small BAT airports are expected to incur annualized compliance 

costs exceeding 3 percent of airport operating revenues. 

 In general, airlines are not directly subject to the final rule. In a small number of cases, 

airlines are co-permittees on NPDES permits at certain airports, and such co-permittee airlines 
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are therefore subject to the final rule. EPA determined that 18 airlines considered small by SBA 

standards are co-permittees, but based on the analytic approach described in Section VIII.C.3, 

none are expected to be significantly impacted by the rule 

Although this final rule will not have a significant economic impact on a substantial 

number of small entities, EPA undertook a number of steps to minimize the impact of this rule 

on small entities. According to the FAA National Plan of Integrated Airport Systems (2007–

2011), there are almost 3,000 public use general aviation and reliever airports in the U.S., some 

of which have substantial cargo service. Many, if not most, of these airports are likely to be 

owned by small government entities. Also likely to be owned by small governmental entities are 

approximately 135 non-primary commercial service airports. EPA has chosen not to regulate 

any general aviation, reliever, or non-primary commercial service airports under today’s final 

rule. EPA also estimates that in addition to the 20 small government-owned primary commercial 

airports, another 52 primary commercial airports are owned by small government entities, but 

will be out-of-scope of the regulation because little or no ADF is used at those airports. 

D. Unfunded Mandates Reform Act 

 This rule does not contain a Federal mandate that may result in expenditures of $100 

million or more for State, local, and tribal governments, in the aggregate, or the private sector in 

any one year. As explained in Section VIII and the TDD, the annual cost of the rule is $78 

million. Thus, this rule is not subject to the requirements of sections 202 or 205 of UMRA. 

 By statute, a small government jurisdiction is defined as a government with a population 

less than 50,000 (5 U.S.C. sec. 601). Because all in-scope airports are owned by a government 

or governmental agency, the definition for a small airport is identical for the purposes of both 

UMRA and SBREFA. If the rule exceeds annual compliance costs of $100 million in aggregate 
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all provisions of UMRA will need to be met. If the rule does not exceed $100 million in 

aggregate costs, but small airports are significantly or uniquely affected by the rule, EPA will be 

required to develop the small government agency plan required under section 203 of UMRA 

because these airports are owned by small governments. 

 This rule is also not subject to the requirements of section 203 of UMRA because it 

contains no regulatory requirements that might significantly or uniquely affect small 

governments. The scope of the rule focuses on the airports that are the largest users of ADF. 

The rule is not projected to exceed $100 million in aggregate annual compliance costs. Further, 

as discussed in Section XII.C above, EPA has determined the rule will not have significant 

economic impact on a substantial number of small entities. 

E. Executive Order 13132: Federalism 

 This action does not have federalism implications. It will not have substantial direct 

effects on the States, on the relationship between the national government and the States, or on 

the distribution of power and responsibilities among the various levels of government, as 

specified in Executive Order 13132 (64 FR 43255, August 10, 1999). Today’s final rule requires 

airports to implement water pollution control requirements through a long-established regulatory 

mechanism, i.e. NPDES, which is jointly administered by EPA and states. EPA expects the rule 

will have little effect on the relationship between, or the distribution of power and 

responsibilities among, the federal and state governments. Thus, Executive Order 13132 does 

not apply to this action. In the spirit of Executive Order 13132 and consistent with EPA policy 

to promote communications between EPA and State and local governments, EPA specifically 

solicited comment on the proposed action from State and local officials, however none were 

received on the topic of federalism. 
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F. Executive Order 13175: Consultation and Coordination with Indian Tribal Governments 

 This rule does not have tribal implications, as specified in Executive Order 13175 (65 FR 

67249, November 6, 2000). It will not have substantial direct effects on Tribal governments, on 

the relationship between the Federal government and Indian Tribes, or on the distribution of 

power and responsibilities between the Federal government and Indian tribes. Today's rule 

contains no Federal mandates for Tribal governments and does not impose any enforceable 

duties on Tribal governments. Thus, Executive Order 13175 does not apply to this rule. In the 

spirit of Executive Order 13175 and consistent with EPA policy to promote communications 

between EPA and Tribal governments, EPA specifically solicited comment on the proposed rule 

on tribal impacts. No comments were received on this topic. 

G. Executive Order 13045: Protection of Children from Environmental Health and Safety Risks 

EPA interprets EO 13045 (62 FR 19885, April 23, 1997) as applying to those regulatory 

actions that concern health or safety risks, such that the analysis required under section 5-501 of 

the Order has the potential to influence the regulation. This action is not subject to EO 13045 

because it is based solely on technology performance.

H. Executive Order 13211: Energy Effects 

 This rule is not a "significant energy action" as defined in Executive Order 13211, 

"Actions Concerning Regulations That Significantly Affect Energy Supply, Distribution, or Use" 

(66 FR 28355, May 22, 2001) because it is not likely to have a significant adverse effect on the 

supply, distribution, or use of energy, as described in Section X.A. of today’s final rule. EPA 

determined that the additional fuel usage would be insignificant, relative to the total fuel 

consumption by airports and airlines, and the total annual U.S. fuel consumption. 
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I. National Technology Transfer Advancement Act 

 Section 12(d) of the National Technology Transfer and Advancement Act (NTTAA) of 

1995, (P.L. 104-113, sec. 12(d); 15 U.S.C. 272 note) directs EPA to use voluntary consensus 

standards in its regulatory activities unless to do so would be inconsistent with applicable law or 

otherwise impractical. Voluntary consensus standards are technical standards (e.g., materials 

specifications, test methods, sampling procedures, and business practices) that are developed or 

adopted by voluntary consensus standard bodies. The NTTAA directs EPA to provide Congress, 

through OMB, explanations when the Agency decides not to use available and applicable 

voluntary consensus standards. 

 The rulemaking involves technical standards. Therefore, the Agency conducted a search 

to identify potentially applicable voluntary consensus standards. However, we identified no such 

standards, and none were brought to our attention in comments. Therefore, EPA decided to use 

the technology-based controls for aircraft and airfield pavement deicing discharges described in 

Section VI. 

J. Executive Order 12898: Federal Actions to Address Environmental Justice in Minority 

Populations and Low-Income Populations 

 Executive Order 12898 (59 FR 7629, Feb. 16, 1994) establishes federal executive policy 

on environmental justice. Its main provision directs federal agencies, to the greatest extent 

practicable and permitted by law, to make environmental justice part of their mission by 

identifying and addressing, as appropriate, disproportionately high and adverse human health or 

environmental effects of their programs, policies, and activities on minority populations and lowincome populations in the United States. 
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 EPA has determined that this final rule will not have disproportionately high and adverse 

human health or environmental effects on minority or low-income populations because it 

increases the level of environmental protection for all affected populations without having any 

disproportionately high and adverse human health or environmental effects on any population, 

including any minority or low-income population. The rule will reduce the negative effects of 

discharges from airports to the nation’s waters, to benefit all of society, including minority 

communities. 

K. Congressional Review Act 

 The Congressional Review Act, 5 U.S.C. 801 et seq., as added by the Small Business 

Regulatory Enforcement Fairness Act of 1996, generally provides that before a rule may take 

effect, the agency promulgating the rule must submit a rule report, which includes a copy of the 

rule, to each House of the Congress and to the Comptroller General of the United States. EPA 

will submit a report containing this rule and other required information to the U.S. Senate, the 

U.S. House of Representatives, and the Comptroller General of the United States prior to 

publication of the rule in the Federal Register. A major rule cannot take effect until 60 days after 

it is published in the Federal Register. This action is not a “major rule” as defined by 5 U.S.C. 

804(2). This rule will be effective [30 days after publication in the Federal Register]. 

Appendix A: Abbreviations and Definitions Used in This Document 

ADF—Aircraft deicing fluid (includes anti-icing fluid) 

AFB--Anaerobic fluidized bed treatment technology 

BAT—Best available technology economically achievable, as defined by sec. 301(b)(2)(A) and 

sec. 304(b)(2)(B) of the CWA 
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BOD5—Biochemical oxygen demand 

CAFR—Comprehensive annual financial reports 

COD—Chemical oxygen demand 

CDP—Centralized deicing pad 

CPT—Cost pass-through 

CWA—Clean Water Act 

DSCR—Debt service coverage ratio 

EA—Economic Analysis 

FAA—Federal Aviation Administration 

GARB—General airport revenue bonds 

GCV—Glycol collection vehicle 

Net income—Operating profit minus interest, taxes, depreciation, and non-operating profits and 

losses 

NOI—Notice of Intent to discharge under a general permit (40 CFR 122.28(b)(2)) 

Normalized ADF—ADF less any water added by the manufacturer or customer before ADF 

application. 

NPDES—National Pollutant Discharge Elimination System, as defined by sec. 402 of the CWA 

NSPS—New Source Performance Standards, as defined by sec. 306 of the CWA 

O&M—Operations and maintenance 

Operating profit—Revenues minus cost of providing those services 

POTW—Publicly owned treatment works 

P2—Pollution prevention 

Revenues—Money received for services rendered 
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RFA—Regulatory Flexibility Act 

TDD—Technical Development Document. 

List of subjects in 40 CFR Part 449 

Environmental protection, Airport deicing, Airport, Airline, Waste treatment and disposal, Water 

pollution control. 

Dated: 

____________________________ 

Lisa P. Jackson, 

Administrator. 

 
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 40 CFR part 122 is amended as follows: 

PART 122—EPA ADMINISTERED PERMIT PROGRAMS: THE NATIONAL 

POLLUTANT DISCHARGE ELIMINATION SYSTEM 

Subpart B—Permit Application and Special NPDES Program Requirements 

 

Sec. 122.21 Application for a permit (applicable to State programs, see Sec. 123.25). 

Authority: The Clean Water Act, 33 U.S.C. 1251 et seq.

Add new paragraph (s) to § 122.21 to read as follows: 

 (s) Application requirements for airport deicing permittees subject to 40 CFR part 449. 

In addition to the other application requirements of this section: 

(1) Reporting Normalized Aircraft Deicing Fluid Usage. 

(i) The following reporting requirement applies to permit applications submitted on or 

before [insert date that is five years after date of publication in Federal Register]: When 

submitting a permit renewal application or NOI, if an existing point source with at least 1,000 

annual non-propeller aircraft departures has collected data on the annual volume of normalized 

aircraft deicing fluid (ADF) it has used in the past, it must report all such data it has collected, 

not to exceed data for the previous five (5) deicing seasons. The existing point source must also 

report the average of the annual normalized ADF used during the years for which it reports data. 

 (ii) The following reporting requirement applies to permit applications submitted after 

[insert date that is five years after date of publication in Federal Register]: When submitting a 

permit renewal application or NOI, an existing point source with at least 1,000 annual nonpropeller aircraft departures must report all data that the existing permit has required it to collect 

on the annual volume of normalized ADF it has used during the term of the existing permit and 

the average annual volume of normalized ADF it has used during this period. 
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 (iii) Alternatively, in lieu of submitting actual normalized ADF usage data under 

subsections (i) or (ii), an existing point source may report that it expects to use an average 

volume of normalized ADF of 60,000 gallons or more per deicing season. 

(2) Selection of a procedure for demonstrating compliance. The following requirements 

apply in the case of permits that are subject to ADF collection requirements in 40 CFR 449.10 or 

40 CFR 449.11: 

(i) Individual permits. An application for an individual permit must include the 

applicant’s selection of a procedure to demonstrate compliance with applicable ADF collection 

requirements as specified in § 449.20(a) for existing sources and § 449.20(b) for new sources. 

(ii) General permits. An existing source seeking coverage under a general permit must 

include in its Notice of Intent its selection of a procedure to demonstrate compliance with 

applicable ADF collection requirements as specified in § 449.20(a). A new source seeking 

coverage under a general permit need not include in its Notice of Intent its selection of a 

procedure to demonstrate compliance with ADF collection requirements – see § 449.20(b) 

(general permits must require use of the procedure specified in that provision). 

 40 CFR part 449 is added as follows: 

PART 449—AIRPORT DEICING POINT SOURCE CATEGORY

Subpart A–Airport Deicing Category

Sec. 

449.1 Applicability. 

449.2 General definitions. 
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449.10 Effluent limitations reflecting the best available technology economically 

 achievable (BAT). 

449.11 New source performance standards (NSPS). 

449.20 Monitoring, reporting and recordkeeping requirements 

Appendix A to 40 CFR Part 449—Sampling Protocol for Soluble COD 

Authority: 33 U.S.C. 1311, 1314, 1316, 1318, 1342, 1361 and 1370. 

Subpart A—Airport Deicing Category

§ 449.1 Applicability. 

 (a) This part applies to discharges of pollutants from deicing operations at Primary 

Airports. 

 (b) Applicability date. The requirements of §449.10(a) apply on or after [insert date that 

is 3 years after the date of publication in the Federal Register]. All other requirements of this 

part apply on or after [insert date that is 30 days after the date of publication in the Federal 

Register]. 

§ 449.2 General definitions. 

The following definitions apply to this part: 

 Advisory circular means a guidance document issued by FAA on methods, procedures or 

facility design. 

Aircraft deicing fluid (ADF) means a fluid (other than hot water) applied to aircraft to 

remove or prevent any accumulation of snow or ice on the aircraft. This includes deicing and 

anti-icing fluids. 

Airfield pavement means all paved surfaces on the airside of an airport. 
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Airside means the part of an airport directly involved in the arrival and departure of

aircraft, including runways, taxiways, aprons and ramps. 

Annual non-propeller aircraft departures means the average number of commercial 

turbine-engine aircraft that are propelled by jet, i.e. turbojet or turbofan, that take off from an 

airport on an annual basis, as tabulated by the Federal Aviation Administration. 

Available ADF means 75 percent of the normalized Type I aircraft deicing fluid and 10 

percent of the normalized Type IV aircraft deicing fluid, excluding aircraft deicing fluids used 

for defrosting or deicing for safe taxiing. 

Centralized deicing pad means a facility on an airfield designed for aircraft deicing 

operations, constructed with a drainage system separate from the airport main storm drain 

system. 

Certification statement means a written submission to the Director that is signed by the 

responsible party as defined in 40 CFR 122.22(a). 

Collection requirement means the requirement in §§ 449.10 and 449.11 for the permittee 

to collect available ADF. 

COD means Chemical Oxygen Demand. 

 Defrosting means the removal of frost contamination from an aircraft when there 

has been no active precipitation. 

 Deicing mean procedures and practices to remove or prevent any accumulation of 

snow or ice on: 

1) an aircraft; or 

2) airfield pavement. 
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 Deicing for safe taxiing means the application of ADF necessary to remove snow or ice 

to prevent damage to a taxiing aircraft. 

 FAA means Federal Aviation Administration. 

 Heating degree day means the number of degrees per day the daily average temperature is 

below 65 degrees Fahrenheit. The daily average temperature is the mean of the maximum and 

minimum temperature for a 24-hour period. The annual heating degree day value is derived by 

summing the daily heating degree days over a calendar year period. 

Notice of Intent (NOI) means a Notice of Intent to discharge under a general permit, as 

described at 40 CFR 122.28(b)(2). 

Normalized aircraft deicing fluid means ADF less any water added by the manufacturer 

or customer before ADF application. 

Plug and pump collection system means a system of devices and equipment that alter an 

airport’s existing storm drain system to contain and collect ADF-contaminated stormwater. This 

includes, but is not limited to, temporary blocking devices at storm drain inlets, glycol collection 

vehicles, and/or installation of shutoff valves in the storm sewer system. 

Primary Airport means an airport defined at 49 U.S.C. 47102 (15). 

§ 449.10 Effluent limitations representing the best available technology economically 

achievable (BAT). 

Except as provided in 40 CFR 125.30 through 125.32, any existing point source with at 

least 1,000 annual non-propeller aircraft departures must comply with the following 

requirements representing the degree of effluent reduction attainable by the application of the 

best available technology economically achievable (BAT): 
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(a) Where average annual normalized ADF usage, as reported pursuant to 40 CFR 

122.21(s)(1), is 60,000 gallons or greater: 

(1) Collection requirement. The existing point source must collect at least 40 percent of 

available ADF; and 

(2) Numerical effluent limitation. The existing point source must achieve the numeric 

effluent limitations in Table I for available ADF collected pursuant to paragraph (1) of this 

subsection. The limitation must be met at the location where the effluent leaves the on-site 

treatment system utilized for meeting these requirements and before commingling with any nondeicing discharge. 

Table I 

BAT Limitations 

Wastestream Pollutant 

Daily 

Maximum 

Weekly 

Average 

Aircraft Deicing COD 271 mg/L 154 mg/L 

(b) Airfield pavement deicing discharges. There shall be no discharge of airfield 

pavement deicers containing urea. To comply with this limitation, any existing point source 

must certify annually that it does not use airfield deicing products that contain urea or 

alternatively, airfield pavement discharges at any discharge point must achieve the numeric 

limitations for ammonia in Table II, prior to any dilution or commingling with any non-deicing 

discharge. 
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Table II 

BAT Limitations 

Wastestream Pollutant 

Daily 

Maximum 

Airfield Pavement 

Deicing

Ammonia as 

Nitrogen

14.7 mg/L 

§ 449.11 New source performance standards (NSPS). 

 New sources with at least 1,000 annual non-propeller aircraft departures must achieve the 

following new source performance standards: 

(a) All new sources located in an area with more than 3,000 annual heating degree days 

must comply with the following requirements: 

(1) Collection requirement. The new source must collect at least 60 percent of available 

ADF; and 

(2) Numerical effluent limitation. The new source must achieve the performance 

standards in Table III for available ADF collected pursuant to paragraph (1) of this subsection. 

The limitation must be met at the location where the effluent leaves the on-site treatment system 

utilized for meeting these requirements and before commingling with any non-deicing discharge. 
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Table III 

NSPS 

Wastestream Pollutant 

Daily 

Maximum 

Weekly 

Average 

Aircraft Deicing COD 271 mg/L 154 mg/L 

(b) Airfield pavement deicing discharges. There shall be no discharge of airfield 

pavement deicers containing urea. To comply with this limitation, any new source must certify 

annually that it does not use airfield deicing products that contain urea or alternatively, airfield 

pavement discharges at any discharge point must achieve the numeric limitations for ammonia in 

Table IV, prior to any dilution or commingling with any non-deicing discharge. 

Table IV 

NSPS 

Wastestream Pollutant 

Daily 

Maximum 

Airfield Pavement 

Deicing

Ammonia as 

Nitrogen

14.7 mg/L 

§ 449.20 Monitoring, reporting and recordkeeping requirements. 

(a) Demonstrating compliance with the ADF collection requirement for existing point 

sources subject to BAT collection requirements in § 449.10. Except as provided in 40 CFR 

125.30 through 125.32, an existing point source that is an individual permittee shall select a 
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procedure under either subsections (1) or (2) below in its permit application as the procedure for 

the permittee to demonstrate compliance with the applicable collection, reporting and 

recordkeeping requirements of this Part. If the permittee selects a procedure under subsection 

(1), the Director shall specify in the permit the procedure chosen by the permittee. A procedure 

selected by the permittee under subsection (2) may be included in the permit only with the 

Director’s approval, as described in subsection (2). General permits must require the permittee 

to use one of the procedures in subsection (1) for demonstrating compliance with the applicable 

collection, reporting and recordkeeping requirements of this Part and may not allow the use of 

procedures in subsection (2). In its Notice of Intent, a prospective general permittee must select 

which of the procedures under subsection (1) it will use: 

(1) The permittee shall maintain records to demonstrate, and certify annually, that it is 

operating and maintaining one of the following ADF collection technologies according to the 

technical specifications set forth in paragraphs (i) or (ii). For both individual and general 

permits, these technical specifications shall be expressly set forth as requirements in the permit. 

The permittee’s demonstration and valid certification are sufficient to meet the applicable BAT 

collection requirement without the permittee having to determine the numeric percentage of 

available ADF collected. 

(i) Centralized Deicing Pads. Operation of a centralized deicing pad in accordance with 

these technical specifications meets the requirement to collect at least 40 percent of the available 

ADF. 

(A) Each centralized deicing pad shall be sized and sited in accordance with all 

applicable FAA advisory circulars. 
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(B) Drainage valves associated with the centralized deicing pad shall be activated before 

deicing activities commence, to collect available ADF. 

(C) The total volume of normalized ADF sprayed at centralized deicing pads(s) must 

exceed 67 percent of the total volume of normalized ADF sprayed for the airport for each deicing 

season, not including ADF sprayed for purposes of defrosting or deicing for safe taxiing. 

(D) The centralized deicing pad and associated deicing equipment shall be installed and 

maintained per any applicable manufacturers’ instructions, and shall be inspected, at a minimum, 

at the beginning of each deicing season to ensure that the pad and associated equipment are in 

working condition. 

 (ii) Plug and Pump Collection System. Operation of a plug and pump collection system 

in accordance with these technical specifications is sufficient to demonstrate compliance with a 

requirement to collect at least 40 percent of the available ADF. 

(A) All aircraft deicing shall take place in a location with an active plug and pump 

system, except for defrosting and deicing for safe taxiing. 

(B) Prior to aircraft deicing at a location, all drain blocks associated with the deicing 

location, including diversion valves, catch basin inserts, etc. shall be installed or activated in 

accordance with manufacturer specifications. 

 (C) All open drains serving areas in which aircraft deicing is occurring, shall either be 

blocked or have runoff diverted to another drainage area in order to segregate ADF-contaminated 

water. 

(D) Pumping, vacuuming or other means of ADF transport shall occur as soon as is 

practicable and consistent with safe airport operations. 
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(E) All equipment used in blocking storm drains, diverting runoff, or 

pumping/collecting/transporting ADF-contaminated water shall be installed and maintained per 

any applicable manufacturer’s instructions, and shall be inspected, at a minimum, at the 

beginning of each deicing season to ensure the device is in working condition. 

(F) Glycol collection vehicles shall be used as ancillary collection for ADF overspray, to 

the extent airport traffic allows. 

(2) Alternative technology or specifications. 

(i) An individual permittee may request that the permit specify one of the following 

alternative procedures for demonstrating compliance with its collection requirement, instead of 

specifying one of the procedures in subsection (1). The permittee must submit all information 

and documentation necessary to support this request. The permittee may request this alternative 

procedure in its application for permit renewal. During the term of a permit, the permittee may 

also request this alternative procedure as a permit modification, subject to the requirements and 

procedures at 40 CFR 122.62 and 40 CFR part 124. If the Director determines, in his or her 

discretion, that the requested alternative procedure will achieve the collection requirement in the 

permit, the Director shall approve the request: 

 (A) the use of a different ADF collection technology from the technologies specified in 

paragraph (a) (1) of this section; or 

 (B) the use of the same ADF collection technology, but with different specifications for 

operation and/or maintenance; or 

 (C) the use of a combination of any of the above ADF collection technologies. 

 (ii) Pollution prevention credit. A permittee may apply for, and obtain credit towards, 

compliance with some or all of the available ADF collection requirement, provided the permittee 
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can demonstrate to the Director’s satisfaction that it employs a pollution prevention technique 

that reduces the amount of available ADF. The credit shall be equivalent to the demonstrated 

reduction in available ADF. 

(iii) The Director shall set forth technical specifications for proper operation and 

maintenance of the chosen collection technology and these technical specifications must be 

expressly included as requirements in the permit. The permittee must maintain appropriate 

records to demonstrate compliance with these requirements. This demonstration constitutes 

compliance by the permittee with the percent capture requirement without the permittee having 

to determine the numeric percentage of ADF that it has collected. Before the Director may 

approve an alternate technology under this subsection, the permittee must demonstrate to the 

Director’s satisfaction that the alternate technology will achieve the applicable percent capture 

requirement. 

(b) Demonstrating compliance with the ADF collection requirement for dischargers 

subject to NSPS collection requirements in § 449.11. Except as provided in 40 CFR 125.30 

through 125.32, an individual permittee shall select a procedure under either subsections (1) or 

(2) below in its permit application as the procedure for the permittee to demonstrate compliance 

with the applicable collection, reporting and recordkeeping requirements of this Part. If the 

permittee selects a procedure under subsection (1), the Director shall specify in the permit the 

procedure chosen by the permittee. A procedure selected by the permittee under subsection (2) 

may be included in the permit only with the Director’s approval, as described in subsection (2). 

General permits must require the permittee to use the procedure in subsection (1) for 

demonstrating compliance with the applicable collection, reporting and recordkeeping 

requirements of this Part and may not allow the use of procedures in subsection (2): 
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(1) The permittee shall maintain records to demonstrate, and certify annually that it is 

operating and maintaining one or more centralized deicing pads. This technology shall be 

operated and maintained according to the technical specifications set forth in paragraphs (i) 

through (iv). For both individual and general permits, these technical specifications shall be 

expressly set forth as requirements in the permit. The permittee’s demonstration and valid 

certification are sufficient to meet the applicable NSPS collection requirement without the 

permittee having to determine the numeric percentage of available ADF collected. 

(i) Each centralized deicing pad shall be sized and sited in accordance with all applicable 

FAA advisory circulars. 

(ii) Drainage valves associated with the centralized deicing pad shall be activated before 

deicing activities commence, to collect available ADF. 

(iii) The centralized deicing pad and associated deicing equipment shall be installed and 

maintained per any applicable manufacturers’ instructions, and shall be inspected, at a minimum, 

at the beginning of each deicing season to ensure that the pad and associated equipment are in 

working condition. 

(iv) All aircraft deicing shall take place on a centralized deicing pad, with the exception 

of defrosting and deicing for safe taxiing. 

(2) Alternative technology or specifications. 

(i) An individual permittee may request that the permit specify one of the following 

alternative procedures for demonstrating compliance with its collection requirement, instead of 

specifying the procedure in subsection (1). The permittee must submit all information and 

documentation necessary to support this request. The permittee may request this alternative 

procedure in its initial permit application or permit renewal application. During the term of a 
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permit, the permittee may also request this alternative procedure as a permit modification, 

subject to the requirements and procedures at 40 CFR 122.62 and 40 CFR part 124. If the 

Director determines, in his or her discretion, that the requested alternative procedure will achieve 

the collection requirement in the permit, the Director shall approve the request: 

 (A) the use of a different ADF collection technology from the centralized deicing pad 

technology specified in paragraph (d)(1)(i) of this section; or 

 (B) the use of the same ADF collection technology, but with different specifications for 

operation and/or maintenance. 

 (ii) Pollution prevention credit. A permittee may apply for, and obtain credit towards, 

compliance with some or all of the available ADF collection requirement, provided the permittee 

can demonstrate to the Director’s satisfaction that it employs a pollution prevention technique 

that reduces the available ADF. The credit shall be equivalent to the demonstrated reduction in 

available ADF. 

 (iii) The Director shall set forth technical specifications for proper operation and 

maintenance of the chosen collection technology and these technical specifications must be 

expressly included as requirements in the permit. The permittee must maintain appropriate 

records to demonstrate compliance with these requirements. This demonstration constitutes 

compliance by the permittee with the percent capture requirement without the permittee having 

to determine the numeric percentage of ADF that it has collected. Before the Director may 

approve an alternate technology under this subsection, the permittee must demonstrate to the 

Director’s satisfaction that the alternate technology will achieve the applicable percent capture 

requirement. 

 (c) Monitoring requirements. 
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 (1) COD limitation. Permittees subject to the ADF collection and discharge requirements 

specified in § 449.10 or § 449.11 must conduct compliance monitoring to demonstrate 

compliance with the COD limitation. Compliance must be measured at the location where the 

effluent leaves the on-site treatment system utilized for meeting these requirements and before 

commingling with any non-deicing discharge. Effluent samples must be collected following the 

protocol in Appendix A. 

(2) Ammonia limitation. If a permittee chooses to comply with the compliance 

alternative specified in §449.10(b) or §449.11(b), the permittee must conduct compliance 

monitoring at all locations where pavement deicing with a product that contains urea is 

occurring, prior to any dilution or commingling with any non-deicing discharge. 

 (d) Recordkeeping. 

 (1) The permit shall provide that the permittee must maintain on site, for a period of five 

years from the date they are created, records documenting compliance with 40 CFR 449.20(b) 

through (d). These records include, but are not limited to, documentation of wastewater samples 

collected and analyzed, certifications, and equipment maintenance schedules and agreements. 

 (2) At the Director’s discretion, a requirement may be included in the permit for the 

permittee to collect, and maintain on site during the term of the permit, up to five (5) years of 

data on the annual volume of ADF used. 

Appendix A to 40 CFR Part 449—Sampling Protocol for Soluble COD 

This sampling protocol applies only to samples collected for use in measurement of COD when 

demonstrating compliance with the regulations set forth in this part. Collect a representative 

sample of the effluent from the airport deicing treatment system, based on the discharge permit 
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requirements (e.g., a grab sample or a composite sample). Because only the COD sample is 

filtered, do not use in-line filters if collecting a sample with a compositing device. 

Grab Samples 

1. Cap the container and shake the grab sample vigorously to mix it. Remove the plunger from a 

10-mL or larger Luer-lock plastic syringe equipped with an Acrodisc Luer-lock filter containing 

a 1.5-μm glass fiber filter (Whatman 934-AH, or equivalent), and fill the syringe body with 

sample. 

2. Replace the plunger and filter the sample into a clean 50-mL screw-cap glass, plastic, or 

fluoropolymer bottle. 

Note: If testing is being done in the field, or with a test kit product (e.g., Hach Method 

8000), the filtrate may be collected in the test kit vial or container. 

3. Additional 10-mL volumes of sample may be filtered and the filtrate added to the same 

sample bottle. This additional volume may be used to repeat sample analyses or to prepare QC 

samples, as needed. 

4. Unless the filtered sample will be analyzed within 15 minutes, preserve the filtered sample 

with H2SO4 to pH < 2. Cap the bottle and label with the sample number. Place in a cooler on ice 

prior to shipping. 

5. Once at the analytical laboratory, the sample must be stored at ≤ 6 oC and analyzed within 28 

days of collection (see the requirements for COD in Table II at 40 CFR part 136). 

6. Analyze the sample using a method approved for COD in Table IB at 40 CFR part 136. 

Note: Because this procedure is specific to this point source category, it does not appear by 

name in 40 CFR part 136. 
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7. Report the sample results as Soluble COD in units of mg/L. There is no Chemical Abstracts 

Service (CAS) Registry Number for soluble COD. 

Composite Samples 

1. If the sample will be analyzed in a fixed laboratory (as opposed to field testing), transfer at 

least 50 mL of well-mixed sample from the compositing device into a clean 50-mL screw-cap 

glass, plastic, or fluoropolymer bottle. Preserve the sample with H2SO4 to pH < 2. Cap the 

bottle and label with the sample number. Place in a cooler on ice prior to shipping. 

2. Once at the analytical laboratory, the sample must be stored at ≤ 6 oC and analyzed within 28 

days of collection (see the requirements for COD in Table II at 40 CFR part 136). 

3. Prior to analysis, remove the sample from cold storage and allow it to warm to room 

temperature. Shake the sample vigorously to mix it. 

4. Remove the plunger from a 10-mL or larger Luer-lock plastic syringe equipped with an 

Acrodisc Luer-lock filter containing a 1.5-μm glass fiber filter (Whatman 934-AH, or 

equivalent), and fill the syringe body with sample. 

5. Replace the plunger and filter the sample into a clean COD vial or other suitable container. 

6. Additional 10-mL volumes of sample may be filtered and the filtrate added to separate 

containers, as needed, to provide samples for repeat analyses or to prepare QC samples. 

7. Analyze the sample using a method approved for COD in Table 1B at 40 CFR part 136. 

Note: Because this procedure is specific to this point source category, it does not appear by 

name in 40 CFR part 136. 

8. Report the sample results as Soluble COD in units of mg/L. There is no Chemical Abstracts 

Service (CAS) Registry Number for soluble COD.