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

ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 449

[EPA-HQ-OW-2004-0038 FRL-8948-2]

RIN 2040-AE69

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

AGENCY:

Environmental Protection Agency (EPA).

ACTION:

Proposed rule.

SUMMARY:

EPA is proposing 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 would apply to wastewater associated with the deicing of aircraft and airfield pavement at primary commercial airports. The ELGs would be incorporated into the NPDES permits issued by EPA, states or tribes. EPA expects compliance with this regulation to reduce the discharge of deicing-related pollutants by at least 44.6 million pounds per year. EPA estimates the annual cost of the rule would be $91.3 million.

DATES:

Comments must be received on or before December 28, 2009. Under the Paperwork Reduction Act, comments on the information collection provisions must be received by the Office of Management and Budget on or before September 28, 2009.

ADDRESSES:

Submit your comments, identified by Docket No. EPA-HQ-OW-2004-0038 by one of the following methods:

•

http:www.regulations.gov:

Follow the on-line instructions for submitting comments.

•

E-mail: OW-Docket@epa.gov

, Attention Docket ID No. EPA-HQ-OW-2004-0038.

•

Mail:

Water Docket, U.S. Environmental Protection Agency, Mail Code: 4203M, 1200 Pennsylvania Ave., NW., Washington, DC 20460. Attention Docket ID No. EPA-HQ-OW-2004-0038. Please include a total of 3 copies. In addition, please mail a copy of your comments on the information collection provisions to the Office of Information and Regulatory Affairs, Office of Management and Budget (OMB),

Attn:

Desk Officer for EPA, 725 17th St., NW., Washington, DC 20503.

•

Hand Delivery:

Water Docket, EPA Docket Center, EPA West Building Room 3334, 1301 Constitution Ave., NW., Washington, DC, Attention Docket ID No. EPA-HQ-OW-2004-0038. Such deliveries are only accepted during the Docket's normal hours of operation, and special arrangements should be made for deliveries of boxed information by calling 202-566-2426.

Instructions:

Direct your comments to Docket No EPA-HQ-OW-2004-0038. EPA's policy is that all comments received will be included in the public docket without change and may be made available online at

http://www.regulations.gov,

including any personal information provided, unless the comment includes information claimed to be Confidential Business Information (CBI) or other information whose disclosure is restricted by statute. Do not submit information that you consider to be CBI or otherwise protected through www.regulations.gov or e-mail. The www.regulations.gov Web site is an “anonymous access” system, which means EPA will not know your identity or contact information unless you provide it in the body of your comment. If you send an e-mail comment directly to EPA without going through

http://www.regulations.gov

your e-mail address will be automatically captured and included as part of the comment that is placed in the public docket and made available on the Internet. If you submit an electronic comment, EPA recommends that you include your name and other contact information in the body of your comment and with any disk or CD-ROM you submit. If EPA cannot read your comment due to technical difficulties and cannot contact you for clarification, EPA may not be able to consider your comment. Electronic files should avoid the use of special characters, any form of encryption, and be free of any defects or viruses.

Docket:

All documents in the docket are listed in the

http://www.regulations.gov

index. A detailed record index, organized by subject, is available on EPA's Web site at

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

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, will be publicly available only in hard copy. Publicly available docket materials are available either electronically in

http://www.regulations.gov

or in hard copy at the Water Docket in the EPA Docket Center, EPA/DC, EPA West, 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 Water Docket is 202-566-2426.

FOR FURTHER INFORMATION CONTACT:

Eric Strassler, Engineering and Analysis Division,

telephone:

202-566-1026;

e-mail: strassler.eric@epa.gov

or Brian D'Amico, Engineering and Analysis Division,

telephone:

202-566-1069;

e-mail: damico.brian@epa.gov

.

SUPPLEMENTARY INFORMATION:

Regulated Entities

Entities potentially regulated by this action include:

Category

Example of regulated entity

North American Industry Classification System Code

Industry

Primary airports with over 1,000 annual jet departures that conduct deicing operations

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 definitions in § 449.02 of the rule and detailed further in Section IV 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.

How To Submit Comments

The public may submit comments in written or electronic form. (

See

the

ADDRESSES

section above.) Electronic comments must be identified by the docket no. EPA-HQ-OW-2004-0038 and must be submitted as a WordPerfect, MS Word or ASCII text file, avoiding the use of special characters and any form of encryption. EPA requests that any graphics included in electronic comments also be provided in hard-copy form. EPA also will accept comments and data on disks in the aforementioned file formats. Electronic comments received on this notice may be filed online at many Federal Depository Libraries. No confidential business information (CBI) should be sent by e-mail.

Supporting Documentation

The rule proposed today is supported by a number of documents including:

• Technical Development Document for Proposed Effluent Limitation Guidelines and Standards for the Airport Deicing Category (TDD), Document No. EPA-821-R-09-004;

• Economic Analysis for Proposed Effluent Limitation Guidelines and Standards for the Airport Deicing Category (EA), Document No. EPA-821-R-09-005;

• Environmental Impact and Benefit Assessment for Proposed Effluent Limitation Guidelines and Standards for the Airport Deicing Category (EIB), Document No. EPA-821-R-09-003.

These documents are available in the public record for this rule and on EPA's Web site at

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

They are available in hard copy from the National Service Center for Environmental Publications (NSCEP), U.S. EPA/NSCEP, P.O. Box 42419, Cincinnati, Ohio 45242-2419, telephone 800-490-9198,

http://epa.gov/ncepihom.

Overview

The preamble describes the terms, acronyms, and abbreviations used in this notice; the background documents that support these proposed regulations; the legal authority of these rules; a summary of the proposal; background information; and the technical and economic methodologies used by the Agency to develop these regulations. This preamble also solicits comment and data on specific areas of interest.

Table of Contents

I. Legal Authority

II. Purpose and Summary of Proposed Rule

III. Background

IV. Scope/Applicability of Proposed Rule

V. Industry Profile

VI. Summary of Data Collection

VII. Technology Options, Costs, Wastewater Characteristics, and Pollutant Reductions

VIII. Economic Analysis for Airports

IX. Airline Impacts

X. Environmental Assessment

XI. Non-Water Quality Environmental Impacts

XII. Regulatory Implementation

XIII. Statutory and Executive Order Reviews

XIV. Solicitation of Data and Comments

XV. Guidelines for Submission of Analytical Data

Appendix A: Abbreviations and Definitions Used in This Document

I. Legal Authority

EPA is proposing 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.

II. Purpose and Summary of Proposed Rule

Section 304(m) of the CWA, added by the Water Quality Act of 1987, requires EPA to establish schedules for (1) reviewing and revising existing effluent limitation guidelines and standards (“effluent guidelines”) and (2) promulgating new effluent guidelines. On September 2, 2004, EPA published an Effluent Guidelines Plan (69 FR 53705) that established schedules for developing new and revised effluent guidelines for several industry categories. One of the industries for which the Agency established a schedule was the Airport Deicing Category. Today EPA proposes to set national standards for control of wastewater discharges from deicing operations at airports. Deicing operations include removal of ice from aircraft, application of chemicals to prevent initial icing or further icing (anti-icing), and removal of (and preventing) ice from airfield pavement (runways, taxiways, aprons and ramps).

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, 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.

The proposed effluent guidelines and standards address both the wastewater collection practices used by airports, and the treatment of those wastes. Airports within the scope of this proposed rule would be required to collect spent aircraft deicing fluid (ADF) and treat the associated wastewater. Additionally, airports performing airfield pavement deicing would be required to use non-urea-based deicers. The requirements would be implemented in CWA discharge permits.

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 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.

Congress recognized that regulating only those sources that discharge effluent directly into the nation's waters would not be sufficient to achieve the CWA's goals. Consequently, the CWA requires 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) and new source performance standards (sec. 306) promulgated by EPA, or based on best professional judgment where EPA has not promulgated an applicable effluent guideline or new source performance standard. Additional limitations based on water quality standards (sec. 303) may also 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 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 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 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 published permit.

For airports, the major requirements of the MSGP are:

• Develop a stormwater pollution prevention plan (SWPPP), including a drainage area site map, documentation of measures used for management of runoff, an evaluation of runway and aircraft deicing operations, and implementation of a program to control or manage contaminated runoff, including consideration of various listed control practices;

• Implement deicing source reduction measures, including minimizing or eliminating the use of urea and glycol-based deicing chemicals; minimizing contamination of stormwater runoff 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 gal. of glycol based deicing chemicals and/or 100 tons or more of urea annually, monitor discharges quarterly for the first four quarters of the permit cycle, for the following pollutants: biochemical oxygen demand (BOD

5

), 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.

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 limitations (WQBELs). Information on water quality-based permitting is available on EPA's Web site 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 directed that EPA 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 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, non-water 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 “cost-reasonableness” test. EPA explained its methodology for the development of BCT limitations in July 1986 (51 FR 24974). Section 304(a)(4) designates the following as conventional pollutants: biochemical oxygen demand measured over five days (BOD

5

), 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 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. 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)

Pretreatment standards apply to discharges of pollutants to publicly owned treatment works (POTW) rather than to discharges to waters of the United States. 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 technology-based and are analogous to BAT effluent limitation guidelines. The General Pretreatment Regulations, which set forth the framework for the implementation of categorical pretreatment standards, are found at 40 CFR part 403. These regulations establish pretreatment standards that apply to all 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 at the same time it promulgates new source performance standards. Such pretreatment standards must prevent the discharge of any pollutant into a POTW that may interfere with, pass through, or may otherwise be incompatible with the POTW. EPA promulgates categorical pretreatment standards for existing sources based principally on BAT technology for existing sources. 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.

IV. Scope/Applicability of Proposed Rule

EPA solicits comments on various issues specifically identified in this preamble as well as any other issues related to this rule that are not specifically addressed in today's notice.

A. Facilities Subject to 40 CFR Part 449

EPA is proposing to establish effluent limitation guidelines and standards for primary commercial airports that conduct deicing operations and have more than 1,000 annual departures of scheduled commercial jet aircraft. Further information on the rationale for the proposed scope is provided in Section VII.D.1 of this preamble and in both the TDD and the EA.

B. Overview of Technology Requirements

The proposed rule would require an airport subject to this Part to:

• Collect at least a specified proportion (either 20 or 60 percent) of available ADF after it is sprayed on aircraft;

• Meet a specified numeric effluent limit for ADF wastewater collected and discharged on site; and

• Certify that it uses airfield pavement deicers that do not contain urea.

All references to ADF in today's proposed rule are for normalized ADF, which is ADF less any water added by the manufacturer or customer before ADF application.

The technologies that serve as the basis for the proposed ELGs are summarized in Table IV-1 and Figure IV-1. These provisions are explained in Section VII of this preamble.

Table IV-1—Summary of Proposed Airport Deicing Effluent Limitation Guidelines and Standards

Regulatory level

Technology basis

Technical components

Airports > 1,000 annual jet departures and

>= 10,000 annual departures

Airports > 1,000 annual jet departures and

< 10,000 annual departures

BAT

1. 60% or 20% ADF capture

1. Capture 60% of available ADF (for airports having >= 460,000 gal. ADF usage) or capture 20% (for airports < 460,000 gal. ADF usage)

1. Certify use of non-urea-based pavement deicers or Meet effluent limit for ammonia.

2. Biological treatment

2. Treat wastewater to meet effluent limit for chemical oxygen demand (COD).

3. Pavement deicer product substitution

3. Certify use of non-urea-based pavement deicers or Meet effluent limit for ammonia.

NSPS

1. 60% ADF capture

1. Capture 60% of available ADF

1. Certify use of non-urea-based pavement deicers or Meet effluent limit for ammonia.

2. Biological treatment

2. Treat wastewater to meet effluent limit for chemical oxygen demand (COD).

3. Pavement deicer product substitution

3. Certify use of non-urea-based pavement deicers or Meet effluent limit for ammonia.

Note:

All references to ADF are for normalized ADF, which is ADF less any water added by the manufacturer or customer before ADF application.

EP28AU09.006

V. Industry Profile

A. Airport Population

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 Non-Primary), 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 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.

B. FAA Deicing Requirements

The Federal Aviation Administration requires airlines to deice aircraft and airfield pavement to protect the safety of passenger and cargo operations. FAA regulations in 14 CFR Part 121 require a complete deicing/anti-icing program. The regulations in 14 CFR Parts 121, 125 and 135 regulate takeoff when snow, ice, or frost is adhering to wings, propellers, control surfaces, engine inlets, and other critical surfaces of the aircraft. FAA does not require airlines to use a specific technology when deicing aircraft. In fact, airlines develop their own deicing protocols to meet the requirements of 14 CFR 125.221. Additionally, FAA has released Advisory Circulars (AC) which provide guidance for aircraft and airfield deicing, including AC 20-73A (Aircraft Ice Protection), AC 135-16 (Ground Deicing & Anti-icing Training & Checking), AC 120-58 (Pilot Guide: Large Aircraft Ground Deicing) and AC 150/5300-14B (Design of Aircraft Deicing Facilities). Advisory Circulars are available on FAA's Web site at

http://www.airweb.faa.gov.

C. Description of Deicing Operations

A major concern for the safety of passengers is the clearing of ice and snow buildup on runways, taxiways, roadways, gate areas, and aircraft. Two basic types of deicing/anti-icing operations are generally performed at an airport: the deicing/anti-icing of aircraft, and the deicing/anti-icing of paved areas, including runways, taxiways, roadways, and gate areas. The most common technique for the deicing/anti-icing of aircraft is the application of chemical deicing/anti-icing agents. Deicing of runways, taxiways, and roadways is most commonly performed using mechanical means, but may also be performed using chemical agents. The anti-icing of paved areas is typically conducted with anti-icing chemicals.

1. Aircraft Deicing

Aircraft deicing involves the removal of frost, snow, or ice from an aircraft. Aircraft anti-icing generally refers to the prevention of the accumulation of frost, snow, or ice. The responsibility for performing deicing/anti-icing varies between airports, but it is usually performed by a combination of individual airlines and support contractors, commonly called fixed-base operators (FBOs) or ground service providers. Airlines typically select procedures for deicing/anti-icing their aircraft, which are then approved by the FAA.

a. Chemical Deicing Practices

In the deicing/anti-icing process, aircraft are usually sprayed with deicing/anti-icing fluids (ADF) that contain chemical deicing agents; however, non-chemical methods are also performed. Deicing/anti-icing occurs when the weather conditions are such that ice or snow accumulates on an aircraft. During snowstorms, freezing rain, or cold weather that causes frost to accumulate on aircraft surfaces including the wings, deicing is necessary to ensure the safe operation of aircraft. Studies have concluded that even a small amount of ice, if located on critical aircraft surfaces (

e.g.,

leading edge of the wing), can cause significant decreases in lift.

The typical deicing season runs from October through April for most airports in the northern U.S. In colder areas, the deicing season may extend over a longer period. In warmer climates, the deicing season may be shorter or deicing may rarely occur. However, it is important to note that deicing may be needed in hot, humid areas at any time. Some aircraft may experience frost build-up after landing at an airport in a hot, humid area. (The phenomenon is similar to frost forming on a cold glass of water exposed to hot, humid air and occurs for the same reason that the cold glass developed frost. Fuel chills when a plane operates at high altitudes where the temperature is very cold. When the plane lands in a hot, humid area, the cold fuel chills the fuel tank. If the tank is very close to the surface of the wing, it causes frost to form on the wing.)

ADF works by adhering to aircraft surfaces to remove and/or prevent snow and ice accumulation. Non-chemical methods include the use of mechanical or thermal means (

e.g.,

infrared heating) to prevent, remove, or melt ice and snow. Two types of deicing are performed: Wet-weather and dry-weather deicing, depending on a number of climatic and operational factors. Wet-weather deicing is performed during storm events that include precipitation such as snow, sleet, or freezing rain. Dry-weather deicing is performed when changes in the ambient temperature cause frost or ice to form on aircraft but no precipitation is present. Dry-weather deicing may also be performed on some types of aircraft whose fuel tanks become super-cooled during high-altitude flight, resulting in ice formation at lower altitudes and after landing. Dry-weather deicing may occur at temperatures up to 55° Fahrenheit (F), but generally requires a significantly smaller volume of deicing fluid than wet-weather deicing.

During typical wet-weather conditions, 150 to 1,000 gallons of ADF may be used on a single commercial jet, while as little as 10 gallons may be used on a small corporate jet. An estimated 1,000 to 4,000 gallons may be needed to deice a larger commercial jet during severe weather conditions. Aircraft anti-icing fluids are applied in much smaller volumes than their deicing counterparts are. A commercial jet requires approximately 35 gallons of fluid for anti-icing after deicing. Generally, dry-weather deicing requires 20 to 50 gallons of deicing fluid, depending on the size of the aircraft.

Chemical aircraft deicers are categorized into four classes. Not all types are currently used. Fluid types vary by composition and allowed holdover time (the estimated time for which deicing/anti-icing fluid will prevent the formation of frost or ice and the accumulation of snow on the treated surfaces of an aircraft). Type I is the most commonly used fluid and is used primarily for aircraft deicing. These types of fluids typically contain glycol as the active ingredient (usually ethylene glycol or propylene glycol), along with water and additives, and remove accumulated ice and snow from aircraft surfaces. Types II, III, and IV were developed for anti-icing. These fluids form a protective anti-icing film on aircraft surfaces to prevent the accumulation of ice and snow. Anti-icing fluids are composed of either ethylene glycol or propylene glycol, a small amount of thickener, water, and additives. The additives in aircraft

deicing and anti-icing fluids may include corrosion inhibitors, flame retardants, wetting agents, identifying dyes, and foam suppressors. Type IV fluids can provide up to a 70 minute holdover time, depending on atmospheric conditions. (Holdover time is the amount of time a given aircraft treatment by ground anti-icing fluid remains effective. Holdover time effectively runs out when frozen deposits start to form or accumulate on treated aircraft surfaces.) Most large airlines use both Type I and Type IV fluids.

Aircraft deicing and anti-icing operations usually occur at terminal gates, gate aprons, taxiways, or centralized deicing pads. Centralized deicing pads may be located near terminals and gates, along taxiways serving departure runways, or near the departure end of runways. Each airport may use only one or a combination of all of these locations for deicing/anti-icing. The amount and type of deicing performed at each location may vary. For example, an airport with deicing pads may allow air carriers to perform minimal deicing at gates, at a level sufficient to move the aircraft safely, and require all other deicing operations to be conducted at a pad.

If deicing is not conducted at the gate, then, prior to takeoff, an aircraft will taxi to an airport-approved deicing/anti-icing location. Depending on the deicing location design, several aircraft may be deiced simultaneously on a single deicing pad. Deicing trucks and/or spray equipment mounted on fixed booms apply the appropriate ADF. One to four deicer trucks may be used for deicing a single aircraft, depending on its size and weather conditions. When holdover times are exceeded prior to takeoff, secondary deicing/anti-icing is necessary. If an aircraft must return to the gate or another designated location for secondary deicing/anti-icing, its departure may be substantially delayed. The need for secondary deicing will likely decrease as more airlines use Type IV fluids to extend the allowable holdover time.

While the FAA has issued regulations and guidance on conducting deicing/anti-icing operations, the aircraft pilot is ultimately responsible for determining whether the deicing performed is adequate. The pilot may inspect the aircraft after deicing and order additional deicing or anti-icing.

Dry-weather deicing, also referred to as clear ice deicing, may be performed whenever ambient temperatures are cold enough to form ice on aircraft wings (below 55° F). Dry-weather deicing is also used to defrost windshields and wingtips on commuter planes and is usually conducted throughout the entire deicing/anti-icing season.

b. Non-Chemical Deicing Practices

Non-chemical deicing methods involve mechanical or thermal means to remove ice and snow from aircraft surfaces. Dry, powdery snow can be swept from aircraft using brooms or brushes. Hot air blowers can also be used to remove snow mechanically with forced air and to melt ice and snow. In addition, some smaller aircraft are equipped with inflatable pneumatic or hydraulic boots that can expand to break ice off the leading edges of wings and elevators.

Mechanical snow removal methods (

e.g.,

using nylon brooms and ropes to remove snow from parked aircraft) are typically only used in the early morning because they are time-intensive and labor-intensive, and would be too disruptive to airline schedules during the day. Mechanical methods are typically also used in conjunction with fluid application and are dependent on climate and operational variables. Personnel must be properly trained and provided with appropriate equipment so as not to damage navigational equipment mounted on aircraft. Airlines typically use brooms to remove as much snow and ice as possible before applying conventional aircraft deicing fluids.

Other non-chemical deicing practices—infrared heating, forced air and hot air systems—are being used at several airports throughout the U.S. These technologies are described in Section VII.B.3, Pollution Prevention Technologies.

2. Airfield Pavement Deicing

Pavement snow removal and deicing/anti-icing removes or prevents the accumulation of frost, snow, or ice on runways, taxiways, aprons, gates, and ramps. A combination of mechanical methods and chemical deicing/anti-icing agents is used for pavement deicing at airports. Runway deicing/anti-icing is typically performed by airport personnel or a contractor hired by the authority. Some ramp, apron, gate, and taxiway deicing/anti-icing may be performed by other entities, such as airlines and FBOs that operate on those areas. Pavement deicing typically occurs during the same season as aircraft deicing, but may be shorter or longer than the aircraft deicing season.

a. Mechanical Methods

Mechanical methods, such as plows, brushes, blowers, and shovels for snow removal, are the most common form of runway deicing, and may be used in combination with chemical methods. Airports generally own multiple pieces of snow removal equipment and have employees trained to operate them. Sand may be used to increase the friction of icy paved areas. Because winter storm events can be unpredictable, personnel trained in pavement deicing/anti-icing may be available at an airport 24 hours a day during the winter season.

b. Chemical Methods

Because ice, sleet, and snow may be difficult to remove by mechanical methods alone, most airports use a combination of mechanical methods and chemical deicing agents. Common pavement deicing and anti-icing agents include potassium acetate, sodium acetate, urea, ethylene glycol-based fluids, propylene glycol-based fluids, and sodium formate. Road salt (

i.e.,

sodium chloride or potassium chloride) may be used to deice/anti-ice paved areas that are not used by aircraft (

e.g.,

automobile roadways and parking areas) but are not considered suitable for deicing/anti-icing taxiways, runways, aprons, and ramps because of their corrosive effects on aircraft.

Many airports perform deicing of heavy accumulations of snow and ice using mechanical equipment followed by chemical applications. Pavement anti-icing may be performed based on predicted weather conditions and pavement temperature. Deicing and anti-icing solutions are applied using either truck-mounted spray equipment or manual methods.

3. Estimates of Deicing Activity

a. Aircraft Deicing Chemical Usage

Airlines use approximately 25 million gallons of ADF annually, consisting of 22.1 million gallons of propylene glycol-based deicers and almost 3 million gallons of ethylene glycol-based deicers. EPA estimates that approximately 320 primary airports conduct deicing operations annually and that approximately 85 percent of this ADF (21.6 million gallons) is used at 110 of the 320 airports.

b. Airfield Pavement Deicing Chemical Usage

Primary airports use approximately 71 million pounds of chemical deicers on airfield pavement (runways, taxiways and ramps) annually. The six most frequently used deicers, with estimated percentages by weight, are as follows: potassium acetate (63 percent); urea (12 percent); propylene glycol-based fluids (11 percent); sodium acetate (9 percent);

sodium formate (3 percent); and ethylene glycol-based fluids (2 percent).

VI. Summary of Data Collection

A. Previous EPA Data Collection Activities

1. 1993 Screener Questionnaire

In 1992, EPA began developing effluent guidelines and standards for the Transportation Equipment Cleaning (TEC) category (40 CFR Part 442). The scope of the TEC regulation at that time included facilities that clean the interiors of tank trucks, rail tank cars, and tank barges; facilities that clean aircraft exteriors; and facilities that deice/anti-ice aircraft and/or airport pavement. Initial data collection efforts for this project related to airport deicing operations included development and administration of a “screener” questionnaire that was administered in 1993. The screener questionnaire was developed, in part, to enable EPA to: (1) Identify facilities that perform TEC aircraft operations; (2) evaluate facilities based on wastewater, economic, and operational characteristics; and (3) develop technical and economic profiles of the industry. Subsequent to distribution of the screener questionnaire, EPA decided not to include the aircraft segment as part of the TEC effluent guidelines that were promulgated in 2000 (65 FR 49665, August 14, 2000). The Agency indicated that its recently-issued stormwater regulations and permits under the NPDES program imposed new requirements for airport discharges, and that aircraft cleaning and airport deicing operations were significantly different from other portions of the TEC category.

EPA mailed the screener questionnaire to 760 entities that potentially perform aircraft exterior cleaning and/or aircraft or pavement deicing/anti-icing operations. Following the screener questionnaire mail-out and analyses of responses, EPA estimated that, in 1993, there were 588 entities

(i.e.

, airlines and FBOs) that perform deicing/anti-icing operations.

2. 1998-99 Preliminary Data Summary

EPA conducted a study of airport deicing practices in 1998-99 and published a report in 2000. (Preliminary Data Summary: Airport Deicing Operations (Revised), Document No. 821-R-00-016, August 2000). The study described deicing operations in the industry, wastewater characteristics and procedures for its collection and treatment. The study was conducted to comply with CWA sec. 304(m), which requires the Agency to publish a biennial Effluent Guidelines Plan, and a consent decree in

Natural Resources Defense Council and Public Citizen, Inc.

v.

Browner

(D.D.C. 89-2980, as modified February 4, 1997). As part of the study, EPA distributed short questionnaires to several aviation sectors, including those involved in deicing; conducted site visits to airports; and conducted wastewater sampling episodes.

a. Questionnaires

In 1999, EPA sent questionnaires to airports, an airline industry association, equipment vendors, and publicly owned treatment works (POTW), and requested data about the 1998-99 deicing season. The Airport Questionnaire was sent to nine airports and asked for information on aircraft and airfield deicing activities; wastewater handling and treatment; and airport structure, finances and operations. A questionnaire requesting financial data was sent to an airline industry association, which provided information about the deicing operations of 12 of its members, and eight regional airlines also received questionnaires. The Vendor Questionnaire was sent to nine businesses and requested information about equipment used to collect, control, recycle/recover, treat or reduce the generation of glycol-contaminated wastewater from aircraft and airfield deicing operations. The POTW Questionnaire was sent to nine facilities and requested information about potential pollutants in wastewater discharges from airports, and the potential environmental impacts stemming from POTWs' acceptance of these wastes.

b. Wastewater Sampling

EPA conducted six sampling episodes for the study. Two of these episodes obtained data on ADF, and four episodes obtained data on ADF-contaminated wastewater and final effluent data from airports with various collection and treatment systems.

c. Airport Site Visits

EPA visited 16 airports between 1997 and 1999 (including one visit before the formal commencement of the study). Information gathered included deicing operations, names and quantities of deicing chemical products used, wastewater characterization, treatment technologies and costs, and financial data. The Agency obtained effluent self-monitoring data from some of the airports that were visited.

d. Other Data Sources

EPA collected data on NPDES permits and from the Toxic Release Inventory database, which have wastewater discharge information. EPA also collected data from state, local, and other federal agencies, including the FAA, Department of Transportation and the United States Geological Survey (USGS); and Canadian federal agencies involved with airport environmental issues. These included interviews conducted during site visits, airport effluent monitoring data, airline operations data (

i.e.

, departures and enplanement statistics), and economic and financial information about the industry. All of the collected data are available in the record for this proposed rule.

B. 2006-07 Industry Surveys

For this proposed rule, EPA developed a series of survey questionnaires to compile a complete profile of the industry with regard to type and amounts of deicing chemicals used, collection systems, and wastewater treatment systems. These questionnaires expanded on the Agency's earlier survey efforts by the design of a scientific national statistical sample of airports and development of a reasonable national estimate of deicing activity by major airlines. A comprehensive set of questions and data tables was also developed. In designing the questionnaires, EPA consulted with airport and airline industry representatives, including the American Association of Airport Executives (AAAE), Airports Council International—North America (ACI-NA) and the Air Transport Association (ATA). The Office of Management and Budget (OMB) approved the questionnaires on January 13, 2006, and EPA distributed the questionnaires during 2006 and 2007.

1. Airline Screener

EPA designed a short “screener” questionnaire to obtain basic information from air carriers on which organizations actually performed deicing services for a particular carrier, at specified airport locations (

i.e.,

the airline conducted its own deicing, it contracted with another airline, or it used an FBO). EPA used the results of this questionnaire to select respondents for the Detailed Airline Questionnaire. The screener was distributed to 72 airlines and requested information on deicing activities at 149 airports. EPA distributed the screener to the industry in April 2006.

2. Airport Questionnaire

EPA designed the Airport Deicing Questionnaire to serve as the Agency's primary data source for airport-specific

information. The questionnaire requested information on a number of topics including, general airport information, deicing operations, deicing stormwater collection and conveyance, deicing stormwater treatment, sampling data, pollution prevention, receiving waters, and airport financial information.

EPA distributed the Airport Deicing Questionnaire to the industry in April 2006. The questionnaire was sent to 153 airports, including a census of all large and medium hub airports, as well as a sample survey of all Small and Non-Hub Airports. (General aviation airports were not included in the survey, except for a few with large cargo operations, because these airports are used mainly by small private airplanes that typically do not fly during icing conditions, and therefore are sites where little or no ADF use occurs.)

3. Detailed Airline Questionnaire

EPA designed the Detailed Airline Questionnaire in order to learn more about the airlines' role in deicing operations, as well as to get information that is more precise on ADF usage. This questionnaire was EPA's primary data source for airline-specific information. The questionnaire asked questions on topics including deicing operations, ADF purchase and usage, pollution prevention practices, and operational costs. The questionnaire was sent in March 2007 to 58 air carriers, covering deicing operations at 57 airports. This questionnaire requested information on a number of topics including: General airline information, airline deicing practices, pollution prevention practices and deicing costs.

C. Site Visits

In order to become familiar with the day-to-day operations at airports, as well as learn some of the more site-specific issues that arise with deicing, EPA conducted site visits at more than 20 airports. EPA visited airports that had specific treatment technologies in place, in order to learn more about these technologies. Some of the airports included were Denver, Pittsburgh and General Mitchell (Milwaukee). All site visits were documented with Site Visit Reports (SVRs), which are in the record for today's proposed rule (Record Index, Section 2.3).

D. Wastewater Sampling Episodes

EPA collected several wastewater samples for chemical analysis during sampling episodes at six airports to characterize pollutants found in ADF-contaminated runoff, and to assess the performance of treatment systems. The Agency conducted episodes at these six airports in 2005 and 2006: Minneapolis/St. Paul International Airport, Detroit Metropolitan Wayne County International Airport, Albany International Airport, Denver International Airport, Greater Rockford (Illinois) Airport, and Pittsburgh International Airport. At the first two airports, EPA conducted one-day sampling episodes, to provide a general characterization of wastewater from deicing operations. The subsequent four events were multiple-day performance sampling episodes, which were designed to document the performance of wastewater treatment systems.

For each analytical chemical class or parameter, EPA collected 24-hour composite samples when possible, in order to capture the variability in the waste streams containing ADF generated throughout the day. EPA used the data from the laboratory analyses of these samples to develop a list of pollutants of concern, and characterize the raw wastewater at airports. EPA used the data collected from the influent, intermediate, and effluent points to analyze the efficacy of treatment at the facilities, and to develop current discharge concentrations, loadings, and the treatment technology options for the Airport Deicing effluent guideline. EPA used effluent data, along with data provided by industry in the questionnaires and other sources, to calculate the long-term averages and limitations for each of the proposed regulatory options. During each sampling episode, EPA collected flow rate data corresponding to each sample collected and production information from each associated production system for use in calculating pollutant loadings. EPA has included in the public record all information collected for which a facility has not asserted a claim of Confidential Business Information (CBI) or which would indirectly reveal information claimed to be CBI.

After conducting the sampling episodes, EPA prepared sampling episode reports for each facility. These reports included descriptions of the wastewater treatment processes, sampling procedures, and analytical results. EPA documented all data collected during sampling episodes in the sampling episode report for each sampled site. Non-confidential business information from these reports is available in the public record for this proposal. For detailed information on sampling and preservation procedures, analytical methods, and quality assurance/quality control procedures see the Quality Assurance Project Plans and the Sampling and Analysis Plans (Record Index, Section 2.4).

E. Other Data Collection

EPA collected other information from various other data sources including: National Pollutant Discharge Elimination System (NPDES) permits for information on current permit requirements; industry correspondence on technology costs and long-term wastewater monitoring data; and searches of technical and scientific literature, covering current deicing practices and treatment technologies, current airport deicing runoff data, chemical information and environmental impact studies, and current stormwater regulations in the United States and other countries.

F. Summary of Public Participation

EPA has met or corresponded with many airport and airline representatives, citizen and environmental groups, vendors of deicing chemicals and equipment, state permit agencies, other Federal agencies and engineering consulting firms. The Agency has attended conferences on airport deicing and has given presentations at several of those conferences. Correspondence from these organizations about the proposed rule is in the Record for the proposed rule.

VII. Technology Options, Costs, Wastewater Characteristics, and Pollutant Reductions

A. Wastewater Sources and Wastewater Characteristics

1. Aircraft Deicing

Most ADF is applied 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. Airlines typically purchase ADF in concentrated form (normalized) and dilute it with water prior to spraying.

Most of the aircraft deicing fluid is Type I fluid, which is not designed to adhere to aircraft surfaces. Consequently the majority of Type I ADF is available for discharge due to dripping, overspraying, 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 pavements. (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.

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 discharge.

For the purposes of this proposed 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 later in this section. 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 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

+

), BOD

5

and COD load as the acetate or formate ion degrades into carbon dioxide (CO

2

) and water. Pavement deicers containing urea will degrade to ammonia, and generate BOD

5

and COD load as well.

Most of EPA's sampling data does not include 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 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 variablity of storm events and drainage systems make it difficult to estimate flows or concentrations of pavement deicing waste streams generated at an airport.

B. Control and Treatment Technologies in the Aviation Industry

The ADF application process has presented a challenge for airports attempting to manage their contaminated stormwater streams. The airlines' process of applying ADF to aircraft through high pressure spraying, combined with their 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, EPA has not identified any single technology that is capable of collecting all applied ADF. Typically, ADF that is not captured becomes available for discharge, either through an airport's drainage system, or from shearing off the aircraft during takeoff.

Once the ADF wastestream is collected, it can be treated, and this process is similar to many other industries that generate wastewater. EPA identified four technologies available for treating ADF wastewater.

EPA also examined pollution prevention technologies, which can reduce or eliminate use of ADF chemicals and urea for pavement deicing.

1. Aircraft Deicing Fluid Collection Technologies

a. Glycol Recovery Vehicle

A glycol recovery vehicle (GRV) is a truck that utilizes a vacuum mechanism to gather stormwater contaminated with ADF resulting from deicing operations. A GRV is a modular technology, in that collection capacity can be increased by using additional units, without the complicating factors of in-ground construction associated with some other technologies. An airport may increase its overall ADF collection capacity by purchasing or leasing larger units and/or additional units.

GRV trucks 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 truck then transports the ADF-contaminated stormwater to an on-site storage facility, after which the material is either treated at the airport or sent off site for treatment. EPA estimates that GRVs typically capture approximately 20 percent of the available ADF when properly operated and maintained.

b. Plug and Pump

The plug-and-pump collection system involves simple alterations to an airport's existing storm drain system, typically the insertion of blocking plugs or similar devices in storm drains, combined with use of GRVs, to contain and collect ADF-contaminated stormwater. Drainage system modifications involve the placement of temporary blocking devices at storm drain inlets, and/or installation of shutoff valves at one or more points in the storm sewer system. Before a deicing event begins, airport personnel activate the blocking devices, which trap the ADF-contaminated stormwater in the collection system. After the deicing activity ceases, the vacuum trucks pump the contaminated stormwater from the storm sewer system and transport the liquid to on-site storage and subsequent treatment. EPA estimates that plug-and-pump systems, which incorporate GRVs, may capture approximately 40 percent of the available ADF when properly operated and maintained.

c. Centralized Deicing Pads

A centralized deicing pad is a facility on an airfield built specifically for aircraft deicing operations. It is typically a paved area adjacent to a gate area, taxiway, or runway, and constructed with a drainage system separate from the airport's main storm drain system. It is usually constructed of concrete with sealed joints to prevent the loss of sprayed ADF through the joints. The pad's collection system is typically connected to a wastewater storage facility, which then may send the wastewater to an on-site or off-site treatment facility.

Some airports use GRVs in combination with centralized deicing pads 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.

Centralized deicing pads reduce the volume of deicing wastewater by restricting deicing to very small areas, and managing the captured wastewater through a dedicated drain system. EPA estimates that central deicing pads allow airports to capture about 60 percent of the available ADF.

In addition, although the name implies a small collection area, central pads designed to accommodate more than one commercial aircraft generally encompass several acres. A deicing pad is specially graded and designed to capture highly contaminated runoff, which can then be sent to storage ponds, tanks or directly to treatment. By capturing high concentrations of spent ADF, the feasibility of recycling increases. Recovered glycol is typically sold to chemical manufacturers for use in a variety of products, including coatings, paints, plastics and polyester fibers.

d. Summary of ADF Collection Technology Usage

EPA estimates the number of airports that use each of the above collection technologies in Table VII-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 VII-1—Estimated Totals of ADF Collection Technologies Used by Airports

Collection technology

Number of airports

Glycol Recovery Vehicle

53

Plug and Pump

29

Centralized Deicing Pad

66

See the Technical Development Document for further explanation of EPA's estimates of the ADF capture rates for the fluid collection technologies.

2. Wastewater Treatment and Recycling Technologies

EPA identified four potential BAT wastewater technologies. Two of these technologies are biological in that they use microorganisms to break down the glycol. The other two technologies are mechanical and produce two wastestreams, one a high concentrated glycol stream, and one that is primarily water for discharge. The high glycol stream can, in some instances, be recycled and used for a variety of products. There have been limited instances in the U.S. of recycled glycol used for ADF formulation.

a. Anaerobic Fluidized Bed

An Anaerobic Fluidized Bed (AFB) treatment system uses a vertical, cylindrical tank in which the ADF-contaminated stormwater is pumped upwards through a bed of granular activated carbon at a velocity sufficient to fluidize, or suspend, the media. A thin film of microorganisms grows on and coats each granular activated carbon particle, providing a vast surface area for biological 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).

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 removed over 98 percent of BOD

5

, over 97 percent of COD, and over 99 percent of propylene glycol from the wastestream. This reduced the BOD

5

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 County Airport in Albany, New York, and Akron-Canton Regional Airport, Akron, Ohio.

b. Ultrafiltration/Reverse Osmosis

Ultrafiltration/Reverse Osmosis (UF/RO) technology filters ADF-contaminated stormwater at a high temperature (75 °C) using an ultrafiltration membrane as its first stage. Next, the deicing fluid (filtrate) can be dewatered using a reverse osmosis membrane as a second stage. Since the ultrafiltration membrane is effective at removing contaminants, the RO stage is used for dewatering and glycol separation. This process produces a glycol-laden stream that can be distilled in an additional stage to increase its glycol concentration. Concentrated glycol streams can be recycled as a feedstock in chemical manufacturing. The effluent from the UF/RO system contains small amounts of glycol, carbonaceous BOD (cBOD) and COD, and can either be discharged to surface water, or sent to a POTW for further treatment.

Based on EPA sampling results, the RO treatment system successfully removed over 99 percent of BOD

5

, over 99 percent of COD, and over 99 percent of propylene glycol. UF/RO technology is used at Pittsburgh International Airport.

c. Mechanical Vapor Recompression and Distillation

Mechanical Vapor Recompression (MVR) followed by distillation is typically used when glycol concentrations in ADF-contaminated stormwater are greater than 5 percent. This type of a system is not generally practical for lower concentration glycol contaminated stormwater, which would typically be discharged directly to a POTW for treatment. The MVR/distillation technology generates a concentrated glycol stream (containing greater than 99 percent glycol) that can be sold as a chemical feedstock. The effluent from the MVR/distillation system contains propylene glycol, cBOD and COD and it must be discharged to a POTW for further treatment.

MVR and distillation is used at Denver International Airport for recycle and recovery of spent ADF. The system first treats ADF-contaminated stormwater using the MVRs, which increase the glycol concentration to approximately 40 percent. Effluent from the MVRs is then treated by distillation to increase the glycol concentration to approximately 99 percent. The glycol product is passed through polishing filters to remove residual contaminants allowing for resale of the product as a chemical feedstock. Overheads (distillate) from both the MVRs and distillation columns contain propylene glycol and they are sent to a POTW for additional treatment.

Based on EPA sampling results, the MVR/Distillation treatment system successfully removed over 93 percent of BOD

5

, over 97 percent of COD, and over 98 percent of propylene glycol.

d. Aerated Pond

An aerated pond uses mechanical aerators either to inject air into the wastewater or to cause violent agitation of wastewater and air in order to achieve oxygen transfer to the wastewater. Bacteria are suspended in the wastewater, and aid in the biodegradation of glycol. Contaminated stormwater is retained in the detention pond during the deicing season and discharged later, after microorganisms present in the pond have biodegraded the glycols. The detention pond is monitored and nutrients are added, pH is adjusted, and anti-foaming agents are added as needed. The biodegradation of glycol is temperature-dependant and predominantly occurs during the spring and early summer months when ambient temperatures are higher. When the BOD

5

concentration has been sufficiently reduced, the volume is discharged to surface waters.

Based on EPA sampling results, the aerated pond treatment system successfully removed 100 percent of BOD

5

, and over 93 percent of COD. An aerated pond system is currently in use

at Greater Rockford Airport, in Rockford, Illinois.

3. Pollution Prevention Technologies

EPA has identified several technologies that reduce ADF usage to some extent while safely deicing aircraft, and one applicable to airfield pavement deicing, that are in use at airports across the United States. However, there are limited data on the actual pollutant reductions that these technologies may achieve. While the effectiveness or cost-effectiveness of these technologies has not been documented, these technologies can reduce the amount of deicing chemicals required to deicing aircraft and airfields. The reduction of chemicals will not only have a positive environmental effect, but may also be cost-effective, as the decrease in costs of purchased deicing chemicals may offset the cost of the technology itself.

a. Infrared Deicing Systems

A few U.S. airports have used infrared (IR) heating systems for several years. The systems have been demonstrated to deice aircraft effectively, which substantially reduces ADF usage. 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, anti-icing fluid is typically applied to the aircraft after it leaves the hangar. Since the aircraft surfaces are dry, the volume of anti-icing fluid required is less than for typical anti-icing operations. 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 greatly reduces the volume required.

Documents provided by a vendor describe use of an IR system that reduces the amount of Type I ADF required by up to 90 percent. Two large hub airports, Newark Liberty International, Newark, New Jersey, and John F. Kennedy International Airport, New York, use IR systems for some of their flights. If this technology can be applied widely, it may prove to be a highly effective means of reducing ADF pollution.

EPA has not obtained substantial data documenting the amount of reduced glycol usage from use of IR systems, nor information on the availability of the technology for broader or industry-wide installation. EPA is interested in receiving any available data on those topics to documenting IR costs including (

e.g.

, the capital costs of installing an IR facility, operating and maintenance costs, especially energy costs, glycol used during deicing and siting/sizing requirements for an IR facility). Because IR is not widely available or used, EPA does not propose to identify IR as an available technology for purposes of establishing ELGs. However, the Agency may reconsider this technology, if sufficient data support a conclusion that this technology is available. Specifically, EPA would require information proving that IR is an available technology for a sufficient percentage of an airports total deicing activity, as well as information on the amount of time required for deicing, as well as any sizing and siting requirements for placing an IR facility.

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 continuing to explore development of deicers that could generate lower levels of pollutants compared to the glycol-based products.

In the field of airfield pavement deicers, several types of products are available as alternatives to glycol-based and urea-based deicers, such as potassium acetate, sodium formate and sodium acetate.

d. Transportation Research Board Report

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 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 in the docket for today's proposed rule.

C. Pollutants of Concern

Airport deicing stormwater is generated when airfield and aircraft deicing/anti-icing chemicals mix with snow, freezing precipitation or rainwater. In addition, other airport-related activities, including aircraft fueling and maintenance activities, may contribute pollutants to stormwater. Because of the difficulties in characterizing airport deicing stormwater, EPA evaluated pollutants detected in the stormwater, pollutants present in source water (

i.e.

, prior to contamination with ADF), and pollutants that are present in ADF prior to use to determine which pollutants are present in deicing stormwater. The primary source of information used to identify potential pollutants of concern from deicing stormwater was EPA's sampling episodes, detailed in Section VI, as well as information presented in available NPDES permits and the Airport Questionnaire.

1. Aircraft Deicers

EPA, through its review of sampling data, discussions with experts in the field of chemical deicers, and review of NPDES permits, identified over 90 pollutants associated with ADF-contaminated stormwater.

EPA shortened the list of pollutants to those that were directly associated with aircraft deicing. This was done by reviewing information provided by

experts and excluding pollutants that were thought to be associated with one of the following sources; source water, aircraft and vehicle fueling operations, maintenance-related operations, or runoff from building roofs.

Having identified pollutants that are present in airport deicing stormwater, the Agency next needed to consider which pollutants should be controlled. EPA did not consider a pollutant as a potential pollutant of concern if it possesses the following characteristics:

• The pollutant is present in the deicing stormwater from a source other than deicing chemical use;

• The pollutant is discharged in relatively small amounts and is neither causing nor likely to cause toxic effects;

• The pollutant is detected in the effluent from only a small number of airports and is uniquely related to those facilities; or

• The pollutant cannot be analyzed by EPA-approved or other established methods.

2. Airfield Deicers

While field information on the constituents of airfield deicing and anti-icing chemicals is scarce, EPA determined which chemicals are commonly used based on the Airport Questionnaire responses. EPA did not identify an available technology to collect and treat pavement deicing pollutants, and therefore did not collect wastewater samples from pavement deicing discharges. Some of the most common airfield deicing and anti-icing chemicals include potassium acetate, sodium acetate, urea, sodium formate, and glycols.

3. Summary

After reviewing these criteria, EPA identified 21 chemicals or parameters as pollutants of concern. Based on our knowledge of usage volumes, and known effects, EPA focused on the glycols in ADF fluids, and the ammonia in urea-based pavement deicers. Section VII.D.2 below discusses how EPA determined which of these pollutants of concern should become regulated pollutants in today's proposed rule.

See

the TDD and the EIB for further discussion of pollutants of concern.

D. Options Considered for Proposal

Current airport deicing operations involve application of chemicals to both aircraft and airfield pavement. ADF may be dispersed over a large area due to the high-pressure spraying process used with aircraft as well as shearing during aircraft taxiing and takeoff. Pavement chemicals, while not sprayed at high pressure, are nonetheless similarly dispersed over a large area, namely runways, taxiways and aprons. The deicing chemicals mix with stormwater and are conveyed through a combination of overland flow and conveyance structures (ditches and pipes). At some airports, the contaminated stormwater is discharged untreated directly to waters of the United States. At other airports, the wastewater is treated before discharge, sent to a POTW or off-site waste contractor, and/or discharged to groundwater.

In order to reduce discharges of untreated ADF wastewater for this industry, EPA concluded that the best available technology would need to include two basic components. The first component is a requirement to capture (collect) a certain percentage of available ADF. The second component is a requirement to treat the collected ADF to meet specified end-of-pipe discharge limitations. In many other industrial sectors, wastewater is typically generated and handled in confined systems such as reactors, pipes and pumps. Wastewater flows are carefully managed in these systems, and under normal operations all wastewater is directed to the facility's treatment system or to a POTW. In aircraft deicing operations, the chemicals are sprayed outdoors in a comparatively unconfined, usually designated setting, and there is a high likelihood that some pollutants will bypass the treatment system. Setting a minimum collection rate in the proposed rule, based on available technology, will require an airport to reduce significantly its level of uncontrolled discharges in an economically achievable manner.

1. Regulated Facilities

Early in the regulatory development process, EPA focused on deicing activities at primary airports, particularly those with extensive jet 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 survey results, EPA estimated that 320 primary commercial airports conduct deicing operations. Any effluent guidelines that EPA might develop for these airports must be “economically achievable” as required by the CWA, so the Agency proceeded to analyze various industry characteristics that would be an indicator of affordability for the candidate control and treatment technologies. This included a review of the relative sizes of various airports (based on annual departures), the levels of deicing activity, traffic characteristics (

i.e.

, passenger vs. cargo operations), the extent of pollution controls and treatment in place, and the costs of various technologies. EPA further classified airports based on the number of annual jet departures. EPA found that there were some primary airports, typically smaller airports, with high percentages of non-jet traffic, and so it excluded airports with 1,000 or fewer annual jet 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). The Agency estimated that the remaining 218 largest primary airports account for approximately 85 percent of the deicing fluid used nationally, and including these airports in the scope of today's proposed rule is economically achievable. Moreover, not applying the 1,000 annual jet departure cutoff would only increase the volume of deicing fluid that is within the scope of today's proposed rule by 1 to 2 percent yet would potentially result in high costs to smaller airports that have minimal pollutant contributions. Accordingly, it is appropriate to establish this exclusion because it avoids projected significant adverse economic impacts on this segment of the industry without excluding from the national standards a significant pollutant load.

2. Regulated Pollutants

As described in Section VII.C, EPA identified 21 pollutants of concern that stem directly from airport deicing operations. EPA estimates, however, that many of these pollutants, such as metals, are generally present in airport stormwater discharges irrespective of deicing activities that are taking place. These pollutants would be also present in discharges at airports where no deicing takes place and as such are beyond the scope of today's proposed rule.

EPA determined that pollutants directly associated with aircraft deicing chemicals could be associated with an indicator pollutant. Initially, both COD and BOD

5

were identified as possible indicator parameters. The Agency determined that COD is the best indicator for the following reasons:

• COD captures the oxygen demand from nitrogen and other organic components of the contaminated

stormwater that may not be represented in a BOD

5

analytical result.

• Toxic aircraft deicing fluid additive compounds in deicing stormwater may have a negative and variable impact on the acclimation of the active cultures used in BOD

5

analysis, making that method less accurate than a COD analysis.

• COD analyses are simple to conduct and can be measured in real time, compared to the 5-day test required by the BOD

5

analytical method.

• The COD analytical method does not require measurement of the receiving water temperature.

Further discussion of analytical methods is provided in a memorandum, “Regulation of COD for Airport Deicing Operations” (DCN AD00845) in the docket for today's proposed rule.

While EPA has an understanding generally of ADF composition—

i.e.,

each product is a glycol-based compound with several additives—deicing fluid manufacturers did not provide us with information on specific ADF formulations. These manufacturers declined several requests to provide information on formulations, citing concerns about confidential business information. EPA has learned about a number of the additives, but not necessarily their concentration, from other sources. Because of incomplete information on these ADF additives, EPA is not proposing numeric effluent limits for any of these additives.

Ammonia is the principal pollutant generated by urea-based pavement deicers, and EPA determined that ammonia is an appropriate indicator pollutant for urea-based airfield pavement deicers.

See the TDD and EIB for further information on regulated pollutants.

3. Technology Options Considered for Basis of Regulation

The effluent limitations that EPA is proposing to establish today are based on well-designed, well-operated collection and treatment systems. Below is a summary of the technology basis for the proposed limitations and the alternative options considered by the Agency. As is the case for any effluent guideline containing numeric effluent limitations, a facility would be able to use any combination of wastewater treatment technologies and pollution prevention strategies at the facility to meet effluent limitations.

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 take into account technological achievability and economic impacts unique to that subcategory. In some cases, effluent 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 the proposed rule, EPA considered whether subcategorizing the aviation industry was warranted. EPA evaluated a number of factors and potential subcategorization approaches, including the presence of an on-site glycol reclamation facility, amount of ADF applied, number of departures, availability of land to install collection systems, and FAA airport classifications.

Establishing formal subcategories is not necessary for the Airport Deicing category because the proposed rule is structured to address the relevant factors (

i.e.,

amount of ADF applied and number of departures) and establish a set of requirements that encompasses the range of situations that an airport may encounter during deicing operations. Both the aircraft deicing and pavement deicing requirements include an airport size threshold, which excludes smaller facilities. The use of a performance standard, as compared to a technology specification, provides flexibility for airports in meeting the requirements. EPA is proposing to establish a set of effluent limitations that take into account the factors that EPA determined are relevant for subcategorizing this point source category.

b. Aircraft Deicing

EPA is proposing capture and treatment requirements for spent ADF. EPA is not aware of an available and economically achievable technology that is capable of capturing 100 percent of the spent ADF, and therefore the Agency is focusing on collection technologies and their efficacy.

i. ADF Collection

The available technologies for collecting ADF—glycol recovery vehicles, plug-and-pump equipment, and deicing pads—are described above. EPA evaluated various different combinations of these collection technologies for different-sized airports. See Table VII-2. These various options were developed to represent a wide range of collection requirements and corresponding costs. EPA's objective was to find a combination of requirements that would result in the greatest level of pollutant removals while still being economically achievable.

Specifically, EPA finds that the number of aircraft departures is an appropriate criterion for grouping airports by size and applying different collection requirements to the various size groups. EPA's review of airline and airport deicing practices revealed that the amount of ADF required to deice a single aircraft varies widely. This is primarily due to the type of weather conditions to which an aircraft is exposed, or aircraft size. However, the Agency has concluded that an airport's overall ADF usage level directly correlates to the amount of wastewater generated and pollutant loadings. Because direct ADF usage data were not available for every airport, EPA determined that the annual number of aircraft departures at an airport, considered simultaneously with precipitation data, is a reliable predictor of ADF usage, based on extrapolations of data provided in the questionnaires.

Based on the available technologies, EPA developed four ADF collection options as listed in Table VII-2 below as candidates for identification as best available technology for the collection of ADF.

Table VII-2—ADF Collection Technology Options Considered for BAT

Option

Requirement (applies to primary airports with more than 1,000 annual jet departures)

Estimated airports in scope

Technology basis

1

20% ADF Capture (Airports w/10,000 or more annual departures)

110

Glycol recovery vehicle (GRV).

2

40% ADF Capture (Airports w/10,000 or more annual departures)

110

Plug & Pump.

3

60% ADF Capture (Airports w/460,000 gals. or more annual ADF usage and 10,000 or more departures) + 20% ADF Capture (Airports w/10,000 or more annual departures and less than 460,000 gals. annual ADF usage)

110 (14 @ 60% + 96 @ 20%)

Centralized Deicing Pad + GRV.

4

60% ADF Capture (Airports w/460,000 gals. or more ADF usage) + 20% ADF Capture (Airports w/1,000 or more jet departures)

218 (14 @ 60% + 204 @ 20%)

Centralized Deicing Pad + GRV.

Note:

All references to ADF are for normalized ADF, which is ADF less any water added by the manufacturer or customer before ADF application.

Not all airports estimated to be in the scope of this proposed rule would incur ADF collection costs under it, because many of these airports already have ADF collection systems in place (Section VIII.C below). For example, of the estimated 14 airports that would have to meet the 60 percent ADF collection requirement in this proposal, seven already have installed deicing pads that would capture at least 60 percent of the ADF.

ii. Treatment

All airports subject to the ADF collection requirement would also be required to treat their ADF wastewater prior to discharge, unless they send this wastewater to a POTW or commercial treatment/recycle facility. EPA examined the four wastewater treatment technologies described above in Section VII.B.2 as candidates for the model BAT technology.

Under this proposal, the collected ADF wastewater would need to be treated to a specified numeric effluent limit for COD. This limit would be based on the long-term averages of effluent from the treatment system identified at BAT (

see

Section VII.E.2 below).

Further discussion of other ADF treatment technologies that EPA considered can be found in the TDD.

c. Airfield Pavement Deicing

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 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 may be 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 urea-based pavement deicers.

Accordingly, to address discharges of ammonia from airfield pavement, EPA identified one candidate for best available technology, namely, discontinuing the use of urea-based pavement deicers and using alternative pavement deicers instead. EPA researched product substitution for urea-based deicers and found that airfield pavement deicers other than urea are widely available in the market and that these alternate deicers do not produce ammonia. Eighty-nine percent of primary airports currently use airfield pavement deicers that do not contain urea. The most widely used substitute product, potassium acetate, accounts for 64 percent (by weight) of the annual airfield pavement deicer usage in the U.S. Urea stood out as an airfield deicer that was not predominantly used in the industry to begin with. Where it is still used, one of the main reasons for its use appears to be low cost compared to other products. Alternatives to urea are available that are equally effective and safe, and would greatly reduce discharges of ammonia from airfield deicing. These alternative airfield deicers include potassium acetate, sodium formate and sodium acetate. In suggesting these alternative deicers, EPA considered environmental impacts and safety issues. The Agency solicits specific data on those issues. EPA has also determined that the use of substitute airfield deicers would be economically achievable in the industry (

see

Section VIII below).

Discontinuing the use of urea-based deicers would greatly reduce ammonia discharges from airfield runoff, but it would not eliminate them entirely because of the background levels of ammonia present in the general runoff from airfields. One method of ensuring that airports discontinue use of urea-based airfield deicers is to require them to certify that they use an alternative deicer. Alternatively, EPA could set a numeric BAT limit on ammonia based on no use of urea that accounts for the remaining sources of ammonia in airport discharges. Product substitution would also result in significant reductions of COD discharges.

See

the further discussion of this issue in the options selection discussion in the next section below.

E. BAT Options Selection

EPA is proposing to identify Best Available Technology Economically Achievable based on Option 3 in Table VII-2. Specifically, this BAT option has the following three components: collection of ADF sprayed onto aircraft based on either GRV or deicing pads (depending on the amount of ADF used), treatment of the collected ADF, if appropriate, based on anaerobic fluidized bed technology, and certification of non-urea-based airfield pavement deicing.

Under Option 3, all primary airports that have over 1,000 annual jet departures and 10,000 or more annual departures would be required to collect at least 20 percent of all available spent ADF. This collection requirement is based on the estimated performance of glycol recovery vehicles. A subset of this group, those primary airports that have more than 1,000 annual jet departures, 10,000 or more annual departures and use 460,000 or more gallons of normalized ADF annually, would be required to collect at least 60 percent of all available spent 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 is based on the estimated performance of centralized deicing pads, which are present at 8 of the 14

primary airports currently meeting the departure/annualized ADF usage criteria noted above. Primary airports with less than 10,000 annual departures would not be required to collect or treat their spent deicing fluid.

The proposed rule would reduce pollutant discharges by 44.6 million pounds annually, comprised of 39.9 million pounds of COD (from both ADF and urea reductions) and 4.7 million pounds of ammonia (from urea alone). The proposed BAT requirements for ADF would reduce the aviation industry's discharges of COD associated with ADF by 27.9 million pounds per year. This represents almost a 22 percent reduction in discharges of ADF-correlated COD relative to current practices used by airlines and airports that conduct deicing. Additionally, the proposed BAT requirements for airfield pavement deicing would reduce discharges of COD (from urea deicers) by 12.7 million pounds per year, and reduce discharges of ammonia by 4.7 million pounds per year.

EPA finds that the proposed BAT technologies are generally available to be installed or used by those in the industry. Further, as will be discussed in more detail in Section VIII below, EPA has determined that the proposed BAT technologies are economically achievable. The Agency also examined the non-water quality environmental impacts of the rule and found them to be acceptable. The technology basis for each requirement—ADF collection, treatment of the collected ADF, and non-urea-based airfield pavement deicing—is discussed below.

1. ADF Collection

For each of the four options in Table VII-2, EPA finds that the collection technology is widely available to the industry.

See

the summary of collection technologies used by airports in Table VII-1. EPA finds that for the top fourteen airports in terms of annual ADF usage, collection of ADF based on the use of deicing pads is technologically available. EPA's record indicates that at least seven of the fourteen airports already have installed deicing pads. For the remaining seven, EPA examined what appeared to be the most land-constrained airports and using a formula based on number of departures and number of runways, estimated the amount of land that would be required for installation of deicing pads. EPA then reviewed airport site plans provided in the questionnaires and determined that these constrained airports have sufficient land to install the necessary collection technologies.

See

the TDD for further discussion on the estimated land availability for deicing pads. Therefore, the Agency determined that economic achievability is the controlling factor in identifying which option represents BAT for collection of ADF.

EPA rejected Option 2, Plug-and-Pump technology, as a basis for BAT for ADF collection. Although Plug-and-Pump is estimated to capture 40 percent of spent ADF, as compared to the other options considered, the equipment has comparatively high operating and maintenance costs. In many cases, EPA estimated that Plug-and-Pump costs would be higher than the cost of deicing pads for a comparable airport, yet deicing pads achieve greater pollutant removals than Plug-and-Pump. Overall, Option 2 achieves lower levels of pollutant removals, and it would impose higher costs than Option 3. Therefore, EPA finds that Option 2 is not the best available technology for ADF collection.

Of the remaining options, Options 1 and 3 are economically achievable while Option 4 is not. Therefore, EPA proposes to identify Option 3 as BAT because it achieves the greatest level of pollutant removals among the remaining options and is economically achievable by the industry. The 60 percent ADF capture and treatment standard for the 14 airports at which the largest ADF usage occurs is expected to result in approximately a 70 percent increase in pollutant removals compared to Option 1 (an increase from 26.4 million pounds to 44.6 million pounds of COD and ammonia removals; see Section 13 of the TDD). Thus, EPA projects that Option 3 will result in significantly greater pollutant removals but little increase in the economic impacts of the rule compared to Option 1. Under Option 3, only two additional airports would incur costs beyond Option 1 that would exceed 3 percent of operating revenue. These two airports are among the largest airports in the U.S. and therefore have the greatest ability to take on these additional costs without undue financial burden. See Section VIII below for EPA's analysis of economic achievability.

Although EPA's analysis indicates that airports have sufficient land to install deicing pads, the Agency invites commenters to provide site-specific data and documentation on any space limitations that would affect an airport's ability to install deicing pads, along with recommendations for alternative ADF collection techniques if deicing pads are not feasible.

EPA is also proposing to allow credit for facilities that might adopt new technologies, such as infrared heating, that use less ADF, but may not change the percent of ADF captured. See proposed § 449.20(b)(2)(i)(C).

2. Treatment

The Agency proposes to identify Anaerobic Fluidized Bed (AFB) as the best available treatment technology for reductions of COD. EPA finds this technology to be widely available to the industry. It is currently in use at two hub airports, Albany International (New York) and Akron-Canton Regional (Ohio).

The other three wastewater treatment technologies that EPA considered were less effective at pollutant removal compared to AFB systems. In addition, treating spent ADF with the mechanical methods, UF/RO and MVR/DC results in a concentrated waste stream that also must be disposed of. While these technologies have potential as a part of an airport's pollutant control strategy, they are not as effective as AFB when used as stand-alone treatment options, i.e. the pollutant removals they achieve are not as great as the removals achieved by AFB systems.

The second biological control option, the aerated pond, was not selected as the technology basis for BAT for mainly logistical reasons. The ponds require large areas for installation, and the normal operations of these systems require treatment for many months after the end of the annual deicing season, before the wastewater can be discharged. Additionally, FAA discourages the installation of new stormwater detention ponds at airports, as they can be a lure for migratory birds. In those situations, birds and aircraft are safety hazards to each other. For airports with existing detention ponds, however, where adequate storage capacity is available, aerated pond systems may be able to provide efficient treatment that meets the standard.

EPA has determined that AFB, as the proposed best available treatment technology for reductions of COD, will also achieve significant reductions of many of the other known pollutants associated with ADF, including 97 percent removal of propylene and ethylene glycol. The AFB treatment system removes over 75 percent of many phenol-ethoxylate compounds as well. Moreover, choosing to set a numeric limit on COD provides an approach that is both effective and is relatively easier and more inexpensive for airports to comply with than a numeric limit on glycols, the active ingredient of aircraft deicing fluids, would be. Monitoring costs for COD are modest relative to some other parameters considered by EPA. Permittees may conduct

monitoring with the use of portable COD meters, which provide immediate, real-time information on the efficacy of their treatment systems and facilitate timely adjustments of system operation where necessary. Overall, EPA's economic analysis shows that the use of AFB technology for treating spent ADF would be economically achievable in the industry. See Section VIII below for more information on economic achievability.

3. Airfield Pavement Deicers

In addition to the requirements that EPA is proposing for ADF sprayed onto airplanes, EPA is also proposing today to identify BAT for the control of deicers that are applied directly to airfield pavement areas. Specifically, as described in Section VIII.D.3, for airfield pavement deicers, EPA is proposing to identify a BAT of discontinuing use of urea-based pavement deicers in favor of alternative, less toxic products that are not harmful to aircraft. Thus, BAT would be based on product substitution rather than treatment of the wastestream that runs off from airfield pavements. To demonstrate that they have used only non-urea based pavement deicers, permittees would be required to submit a certification to that effect.

EPA considered two possible methods for eliminating discharges of ammonia associated with the application of urea-based pavement deicers. One option would be to set a performance-based numeric limit on discharges of ammonia that could be met by using non-urea-based deicers. A second option would require airports to certify that they do not use urea-based airfield deicing products. EPA is proposing today to adopt the certification option. EPA is proposing the certification because it ensures compliance while minimizing compliance costs. Certification allows a facility to demonstrate compliance with this product substitution-based BAT without the expense of conducting monitoring activities. Collecting and analyzing samples of airfield runoff would also present significant practical difficulties. Measuring ammonia discharges from airfield pavement is generally difficult due to the design of airport drainage systems. Wastestreams from multiple areas of an airport may be combined into a single pipe, which complicates the calculation of pollutant concentrations. In addition, the “building block” approach, which has been used to calculate combined wastestream concentrations for other industrial categories, is generally very difficult to perform at airports, due to the variability and unpredictability of the volume of stormwater runoff. Therefore, as a practical matter, a permittee who wanted to take samples and demonstrate compliance with a numeric limit for ammonia would need to show that the ammonia limit is met for all deicing runoff, not just airfield discharges.

While EPA is proposing to identify product substitution as BAT, in order to allow flexibility to regulated facilities, the Agency is also proposing a compliance alternative to the certification requirement. This provision would accommodate facilities that might wish to continue using urea-based deicers and install treatment to eliminate urea-based ammonia discharges instead. Facilities that elect to comply using the compliance alternative would be required to monitor and comply with a proposed ammonia limit. To establish the proposed compliance alternative limitation for ammonia, the Agency had to take into account the ammonia that is a by-product of an AFB wastewater treatment system. This is because AFB discharges could have higher ammonia concentrations than that of background levels found in airfield runoff. While this results in a proposed compliance alternative ammonia effluent limit higher than concentrations in airfield runoff where AFB technologies are not used, the Agency estimates that these concentrations are lower than those from airfield pavement discharges where urea-based deicers are used.

See

“Evaluation of Proposed Compliance Alternative Ammonia Limitations with Respect to Airport Deicing Stormwater Typical Ammonia Discharges,” DCN AD01194, for additional discussion.

Although EPA has developed compliance alternative ammonia effluent limitations for this proposal, it estimates that the cost associated with capturing and treating these waste streams would be prohibitively high for most airports. Therefore, EPA anticipates that most or all airports would choose the certification option rather than the ammonia numeric limits option in order to avoid compliance monitoring. EPA requests comment on implementation challenges associated with and the extent to which regulated facilities may select the compliance alternative. To the extent that comments indicate the compliance alternative would not be utilized, EPA might not include it in the final rule.

F. NSPS

EPA evaluated which technologies should be identified as the “best available demonstrated control technologies” for purposes of setting new source performance standards under CWA section 306. Among the collection technologies that EPA considered, deicing pads capture the greatest level of available ADF and are widely available in the industry. Among the treatment technologies considered, treatment of the captured ADF with an anaerobic fluidized bed system represents the greatest level of removals of the pollutants of concern and is widely available for use in connection with new airports and new runways at existing airports. In considering economic impacts, EPA believes that a standard based on the use of deicing pads for ADF collection followed by treatment with an AFB system would not represent a barrier to entry for new sources in this industry. See the economic analysis discussion in Section VIII. Accordingly, EPA proposes to base NSPS for aircraft deicing on these technologies. As with the BAT requirement for existing sources, the proposed NSPS would require dischargers to collect 60 percent of available spent ADF, and treat the collected wastewater to a specified numeric limit for COD.

Additionally, EPA considered which technology should be considered the basis for setting NSPS with respect to airfield deicing. EPA determined that, just as with existing sources, all new sources would be capable of eliminating the use of urea for airfield deicing in favor of substitute deicing products. Product substitution represents the greatest level of reduction in ammonia among the available technologies considered and product substitution does not appear to represent a barrier to entry. See the economic analysis discussion in Section VIII. Accordingly, EPA proposes to identify elimination of urea followed by product substitution of non-urea-based airfield deicers as the best demonstrated available control technology for purposes of all new sources.

Based on this identified technology, all new sources would be required to meet the same certification requirement proposed for BAT. In addition, as proposed today for existing sources, EPA proposes the same compliance alternative ammonia effluent limitations for new sources.

For the purpose of this regulation, EPA proposes that a “New Source” would include, first, a new airport. The cost of construction of even small airports is significantly greater than the costs associated with collection and/or treatment of spent deicing fluids. Accordingly, meeting the new source requirements proposed today would not be a barrier to entry for them

economically. See further discussion in Section VIII below.

In addition, EPA proposes to specify that a new runway at an existing airport is also a new source. EPA anticipates that few new airports will be constructed in the foreseeable future, and that most of the anticipated increase in airport capacity will be accomplished through the expansion of existing airports. The term “new source” is defined in EPA regulations at 40 CFR 122.2 and 122.29. EPA proposes to specify in the final rule that a new runway meets the terms of those regulations for being defined as a new source, because in EPA's view a new runway is a “structure, facility or installation from which there is or may be a discharge of pollutants” (§§ 122.2 and 122.29(a)(2)) and because a new runway is “substantially independent of an existing source at the same site” (§ 122.29(b)(iii)). EPA does not believe in general that new runways will be significantly integrated with existing airport facilities in a way that should prevent them from being identified as new sources (

see

§ 122.29(b)(iii)). In addition, it is possible that permit authorities, on a case-by-case basis, would be able to deem other types of construction activity for aircraft movement areas to constitute a new source as well. For example, a permit authority might deem the substantial improvement or replacement of an existing runway to be a new source if that activity is deemed to “totally replace the process or production equipment that causes the discharge of pollutants” (

see

§ 122.29(b)(ii)). In all of the situations discussed above, the new runway or other runway construction activity would be deemed to be a new source only if it meets all of the criteria in the regulations cited above for definition as a new source.

G. BPT and BCT

The CWA provides for two increasingly stringent levels of technology-based controls on discharges of pollutants.

See EPA

v.

National Crushed Stone Association,

449 U.S. 64 (1980). BPT represents the first level of control applicable to all pollutants. BCT and BAT represent the second level of control for conventional and toxic/nonconventional pollutants, respectively. EPA considered whether in this rule, it was necessary to establish BPT and BCT limits, given that ADF and pavement deicing fluid will be controlled at the more stringent BAT level. Because the BAT controls in this rule also control the same pollutants as would be controlled by BPT or BCT limits, it is not necessary for EPA to analyze options and propose BPT and BCT effluent limitation guidelines for the Airport Deicing Category. EPA recognizes that it has proposed, in the past, all three levels of control, BPT, BCT and BAT for various industries even where the same pollutants and wastestream were at issue. In this rule however, the Agency solicits comments on this approach because it represents significant resource savings for EPA in terms of analysis and rulemaking process while not sacrificing any environmental protection. Additionally, EPA is not establishing BCT limitations for this industry because these limitations apply only to conventional pollutants such as BOD

5

and total suspended solids and this effluent guideline regulates only non-conventional pollutants (chiefly COD and ammonia).

H. Pretreatment Standards

Some airports in the U.S. discharge ADF-contaminated runoff to POTWs. EPA does not have any information indicating that POTWs currently have problems of pollutant pass-through, interference or sludge contamination stemming from these discharges. For this reason, the Agency is not proposing PSES or PSNS. EPA is aware that high concentration or “slug” discharges of deicing wastewater can create POTW upset, and many of the airports that discharge to POTWs have airport-specific requirements on allowable BOD

5

or COD discharge loading per day. They may also have requirements for discharging at various concentration levels over time. Airports usually meet this requirement by storing deicing stormwater in ponds or tanks and metering the discharge to meet the POTW permit requirements.

I. Compliance Costs

1. Overview

EPA estimated industry-wide compliance costs for this proposed 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.

EPA estimated compliance costs associated with today's proposal using data collected through survey responses, site visits, sampling episodes, specific airport requests and information supplied by vendors. As applicable, EPA estimated the costs for an airport to comply with today's proposal initially, as well as maintaining equipment and performing required monitoring or other activities to demonstrate ongoing compliance. These costs may include upgrading/installing and operating a collection system and/or a treatment system, chemical analysis for compliance as well as the costs associated with substituting potassium acetate in place of urea as a chemical airfield deicer. EPA's cost estimates represent the incremental costs for a facility when its existing practices would not lead to compliance with today's proposed 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 “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 (2002-2005) 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. For example, if an airport installed a deicing pad in 2005, EPA's costing estimates would reflect any incremental changes required above the current ADF collection rate, to meet the collection rate in the proposed rule.

2. Approach for Developing Aircraft Deicing Costs

Under this proposed rule, an airport would be required to collect a percentage of its sprayed ADF, and treat that wastewater to comply with numeric effluent limitations. EPA estimated the costs for an airport to comply with collection and treatment requirements, as well as performing required monitoring to demonstrate compliance. These costs include estimates of upgrading airports' current collection systems, installing the required technology to treat the wastewater, maintaining equipment and conducting chemical analyses for compliance.

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 proposal. In general, when an airport lacked a comparable collection system to the one used as the basis for the options considered in today's proposal, EPA included costs for installation/implementation of one of the following collection technologies: GRVs, GRVs used in conjunction with plug-and-pump systems, or deicing pads.

For estimating wastewater treatment costs, EPA assumed costs for storage of anticipated volumes of collected ADF. Airport-specific costs were assessed for storage options, including ponds, permanent tanks (both underground and aboveground), or mobile/temporary fractional distillation tanks.

EPA based its selection of a particular storage option on an airport's current storage facilities, and on what would be the easiest for that airport to implement. The Agency assumed that it is likely that an airport with a pond already in place would use that for storage, as opposed to constructing permanent tanks; and assumed that an airport with limited available land would install an underground tank.

Based on questionnaire responses and engineering judgment, EPA assessed the current level of treatment for each model facility that discharges directly to waters of the U.S. Except in limited circumstances, when a model facility was determined to require additional treatment, EPA assigned costs associated with installing an AFB treatment system as the most likely means of compliance.

Of the direct discharging model facilities that were modeled for treatment costs, EPA assumed that approximately five percent would use off-site hauling for waste treatment, based on the Agency's estimate that this percentage will find this choice to be the most cost-effective alternative. These facilities have relatively limited deicing operations and off-site hauling is more cost-effective than installing an on-site biological treatment system. Additionally, an on-site biological treatment system would require a regular wastestream flow in order to keep the biological system functioning properly, and an airport with limited deicing operations may have trouble maintaining a regular wastestream.

EPA recognizes that an airport may decide to use a POTW rather than directly discharging its wastewater. While this may be a lower cost alternative in some cases, EPA did not estimate costs for such a change, because the Agency does not have enough information about the capacity of specific POTWs to receive these volumes of wastewater. EPA also was not able to determine if a specific POTW would be unwilling to accept the wastewater from a particular airport, and for other reasons, such as inconsistencies with its future growth plans. For these reasons, EPA did not include this alternative in its model.

An airport that has upgraded its collection and treatment systems may have additional monitoring costs. While the permit authority determines the required monitoring frequency for an individual permittee, EPA estimated the overall costs of the anticipated monitoring requirements associated with the proposed rule. EPA estimated the cost per airport for the ADF collection requirement, and the cost of analyzing COD in the treated effluent. For costing purposes, EPA assumed that an airport would take a 24-hour composite sample and analyze that for COD, and perform that analysis five times per week throughout the deicing season. EPA made a similar assumption for purposes of computing the proposed weekly average effluent limitation. As a conservative estimate, EPA assumed a six-month deicing season for all modeled facilities. Additionally, EPA assumed that the model facility would perform an assessment of their collection system once every permit cycle.

3. Approach for Estimating Airfield Pavement Deicing Costs

Under today's proposal, in addition to the requirements set forth for capture/treatment of aircraft deicing fluid, an airport would be required to certify it uses non-urea-based airfield deicers. Through the results of the Airport Questionnaire, EPA learned that 29 model facilities (a subset of the 149 model facilities referenced above) use urea for airfield pavement deicing. As detailed in Section VII.D.3, EPA based its certification requirement on product substitution. EPA calculated the cost for these 29 model facilities to substitute the urea used for deicing 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 switch to potassium acetate, specifically because that product accounts for 64 percent of the applied chemical airfield deicer usage (by weight) in the U.S.

EPA identified 16 airports that used both urea and potassium acetate for airfield deicing, and 8 of these airports provided usage data. The Agency calculated that the average cost of urea was $274.24/ton and the average cost of potassium acetate was $3.16/gallon. The questionnaire responses indicated that between 2002 and 2005 an average of over 7 million pounds of urea were used annually, costing an estimated $1.06 million.

Urea deicers are applied at a different rate to have an efficacy equivalent to potassium acetate. EPA had to determine what amount of potassium acetate would be required to replace the estimated 7 million pounds of urea used annually. EPA could not locate any information on the relative application rates between potassium acetate and urea directly; however, we did develop a comparison to sodium acetate, another solid pavement deicer. Both urea and potassium acetate application rates vary depending on the weather conditions and the thickness of the ice layer at the time of application. Using the information available, EPA assessed comparable application rates and costs between urea and potassium acetate to treat 1,000 ft

2

of area for thin ice conditions at 32 °F and 1-inch-thick ice conditions at less than 10 °F. DCN AD00843 provides additional details about the calculations on product substitution.

Using the reported urea usage in the Airport Questionnaire, EPA estimated the airfield area that was annually deiced at each model facility. Finally, using the estimated model facility airfield area in conjunction with the estimated $2.32/1,000 ft

2

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 costs to determine the incremental costs of switching chemical airfield deicers.

4. Calculation of National Costs

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).

For each model facility, EPA calculated an annualized cost based on the sum of all the associated O&M costs as well as amortized capital costs. Capital costs were amortized over the lifespan of the capital improvement, as reported by the facility. No capital costs were amortized over more than 20 years, even if an estimated lifespan of an airport exceeded 20 years. Finally, EPA

combined the amortized costs with the annual O&M 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 in order to calculate a national estimated cost of $91.3 million for complying with the proposed rule. Further discussion of all of the calculations discussed above can be found in the TDD.

J. Approach to Estimating Pollutant Reductions

1. Overview

The pollutants of concern associated with airfield and aircraft deicing and anti-icing chemicals are discussed earlier in this preamble. These chemicals commingle with stormwater and they 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. The oxygen demand of compounds can be measured as five-day biochemical oxygen demand (BOD

5

) and chemical oxygen demand (COD), or calculated as theoretical oxygen demand (ThOD).

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, 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 an estimation 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.

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;

• 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

To estimate pollutant loadings from deicing operations, EPA analyzed airports' questionnaire responses and information provided during the site visits. The Agency estimated the total amount of pavement deicing chemicals and ADF used based on data collected in the Airport and Airline Questionnaires.

In the Airport Questionnaire, EPA requested that airport authorities report the purchase/usage amount, concentration, and brand name of pavement deicing materials. EPA evaluated each reported chemical to determine the most appropriate way to estimate the average amount used over the past three winter seasons. EPA also requested the purchase amount, concentration, and brand names of ADF chemicals in the Airline Questionnaire.

The responses to the Airline Questionnaire provided sufficient data to estimate ADF usage at 56 airports. In some cases, data were not available for every airline operating at a particular airport. In these instances, 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 and the total amount of airport operations. In addition to the ADF data reported in the Airline Detailed Questionnaire, 10 airports reported total gallons of ADF usage to EPA in their comment section of the Airport Deicing Questionnaire. These ADF data were combined with the ADF data reported in the Airline Deicing Questionnaires, resulting in estimates of total ADF usage for 66 airports.

Using the Airline and Airport Questionnaire ADF purchase data, airport departure data, and climate data, EPA developed a relationship between the estimate of amount of ADF used, the climate and size of each airport. EPA used this equation to estimate the total gallons of ADF used at airports that did not have available ADF data in the Airport or Airline Questionnaires.

Once the amount of ADF applied at each airport had been determined, EPA needed to determine the amount of ADF available for direct discharge. EPA assumes that 80 percent of applied Type I and Type II 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.) The total amount of applied ADF was multiplied by the appropriate percent available for discharge to determine the amount of ADF that is available for discharge. Note that compliance capture requirements in the proposed 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, would result in the total amount of discharged ADF. After excluding the ADF removed via baseline capture, EPA calculated the amount of COD and BOD

5

loading associated with the degradation of the applied deicing/anti-icing chemicals. EPA later decided that COD was a more accurate and practical indicator to regulate than BOD

5

(see the discussion in Section 7 of the Technical Development Document).

Airfield pavement deicing chemicals are applied at various airside areas where differing activities occur. 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 pavement deicers are discharged to surface waters. This means the estimates of baseline pollutant loadings and removals associated with pavement de-icing are upper bound estimates.

EPA calculated the amount of pollutant loadings discharged to surface waters by using standard published chemical information and stoichiometric equations. This methodology is preferable to using empirical data because it can be applied to all deicing chemicals being used by the aviation industry. In addition, this methodology allows for a clear presentation of the calculations and assumptions used. EPA confirmed the validity of the COD concentrations for propylene glycol and ethylene glycol calculated using this methodology against the available empirical data. See Section 10 of the TDD for more information on calculations of baseline loadings due to airfield deicers.

b. Calculation of Pollutant Removals

EPA estimated the amounts of COD that would be reduced by the proposed rule, by estimating the existing capture and treatment levels at individual airports and comparing that to the levels that would be required by the proposed rule. If a particular airport would be subject to a collection requirement of 20 percent under the proposed rule and it currently is estimated to capture a greater proportion, then no load removals were estimated for that airport. Additionally, if an airport was estimated to use urea for pavement deicing, EPA assumed that the airport would use product substitution to meet the proposed effluent limit. The ammonia and COD loads associated with urea were calculated and then EPA computed the total load reduction by subtracting the ammonia loadings and the COD loadings of the substitute product, potassium acetate. (Although some studies indicate that alternative pavement deicers can be toxic to aquatic organisms, the combined impact of the COD content, toxicity, and nutrient content of urea is greater than effects associated with alternative pavement deicers.)

These calculated loading reductions, for both airfield and aircraft deicing chemicals, were then extrapolated by multiplying the direct discharge loads or load removals by the airport survey weighting factors to determine national loads for the entire industry for baseline and each regulatory scenario. EPA estimates the total annual pollutant removal for the proposed rule at 44.6 million pounds, comprised of 39.9 million pounds of COD and 4.7 million pounds of ammonia. The pollutant removal estimates for the other regulatory options range from 26 million pounds to 46 million pounds.

K. Approach to Determining Long-Term Averages, Variability Factors and Effluent Limitation Guidelines and Standards

This section describes the statistical methodology used to develop the proposed daily maximum and maximum for weekly average effluent limitations for BAT and new source performance standards for COD. EPA also used the same statistical methodology to develop the daily maximum limitation/standard for ammonia that is a proposed compliance alternative when urea is applied to runways. For simplicity, the following discussion uses the term “limitation” to refer to effluent limitations, standards, and the compliance alternative. EPA has proposed the same limitations for each level of recovery requirements, because the treatment technology and performance are the same regardless of the amount of fluid recovered.

The following sections describe the data selection criteria; the statistical percentile basis of the proposed limitations; rationales for proposing 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 proposed limitations.

1. Criteria Used To Select Data as the Basis of the Proposed Limitations

Typically, in developing effluent limitations for any industry, EPA qualitatively reviews all the data before selecting a subset as the basis of 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 good operation. 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 start of every deicing season because they probably will cease treatment operations during warmer months. Because this adjustment period will occur every year for the Airport Deicing Category, EPA is proposing to include start-up data in the data set used as the basis of the limitations. However, through its application of the other three criteria, EPA would exclude extreme conditions that do not demonstrate the level of control possible with proper operation and control even during start-up periods.

In part, by retaining start-up data for limitations development, the limitations will be achievable because EPA based these limits on typical treatment during the entire season. Once the treatment system reaches steady state, EPA expects a typically well-designed and operated system to run continuously until the end of the deicing season. Conversely, EPA might determine that systems that operated only during relatively short periods, such as during each winter storm event (

i.e.,

of only several days duration), might be poorly operated because the model technology requires more time to reach steady state. In other words, it would be ineffective and disruptive to turn the system on and off throughout the deicing season, particularly for biological systems, such as the model technology, and EPA may reject data if it determines that it reflects this type of operation.

2. Data Used as Basis of Proposed Limitations

Of the effluent data available to EPA, 2,562 concentration values for COD and

5 concentration values for ammonia met the requirements in the criteria and are the basis of the proposed limitations. The concentration values are measurements of effluent collected from Albany Airport's 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 five ammonia values were collected by EPA during its sampling episode (February 5 through February 9, 2006). (As explained in Section VII.E.3, EPA transferred the ammonia data from the anaerobic fluidized bed (AFB) technology because an AFB system by design creates ammonia as a by-product of wastewater treatment. Consequently, AFB discharges could have higher ammonia concentrations than typically found in airfield runoff when urea is not present. If the treated aircraft deicing effluent then were discharged through the same pipe as the runway runoff, the airport might have difficulties complying with the ammonia limitation.)

For the final rule, EPA might further explore factors contributing to variability observed in the available data, assess whether some modes of operations do not reflect the performance expected from the model technology (as required by criterion 3), and thus decide whether to exclude any of the corresponding data as the basis of any limitation.

EPA is soliciting additional data on airport discharges (see Section XIV for a detailed request for data). When applying the data selection criteria for the final limitations, EPA will consider new information from commenters and other sources. Consequently, EPA may reach new conclusions about whether some or all of the proposal data should be included or excluded as the basis of the final limitations; and/or revisions to its statistical approach are appropriate. As a result of its evaluation of the new information, EPA may promulgate final limitations that are more or less stringent than the proposed limitations.

3. Statistical Percentile Basis for Limitations

EPA uses a statistical framework to establish limitations that facilities are capable of complying with at all times. Statistical methods are appropriate for dealing with effluent data because the quality of effluent, even in well-operated systems, is subject to a certain amount of fluctuation or uncertainty. Statistics is the science of dealing with uncertainty in a logical and consistent manner. Statistical methods together with engineering analysis of operating conditions, therefore, provide a logical and consistent framework for analyzing a set of effluent data and determining values from the data that form a reasonable basis for effluent limitations. Using statistical methods, EPA has derived numerical values for its proposed daily maximum limitations and weekly average limitations.

The statistical percentiles are intended, on one hand, to be high enough to accommodate reasonably anticipated variability within control of the facility. The limitations also reflect a level of performance consistent with the CWA requirement that these limitations be based on the best technologies that are properly operated and maintained.

In establishing daily maximum limitations, EPA's objective is to restrict the discharges on a daily basis at a level that is achievable for an airport that targets its treatment system design and operation at the long-term average while allowing for the variability around the long-term average that results from normal operations. This variability means that at certain times airports may discharge at 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 considerably lower than the long-term average. To allow for possibly higher daily discharges, EPA has established the daily maximum limitation at a relatively high level (

i.e.,

the 99th percentile). 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 has not promulgated weekly average limitations for other industries, and thus, is soliciting comment on its approach for this industry. Because EPA typically establishes limitations based upon statistical percentile estimates, it is proposing to do so for the weekly average limitation. In its derivation of the weekly average limitation for COD, EPA used an estimate of the 97th percentile of the weekly averages of the daily measurements. This percentile basis is the midpoint of the percentiles used for the daily maximum limitation (

i.e.,

99th percentile of the distribution of daily values) and the monthly average limitation (

i.e.,

95th percentile of the distribution of monthly average values). Courts have upheld EPA's use of these percentiles, and the selection of the 97th percentile is a logical extension of this practice. Compliance with the daily maximum limitation is determined by a single daily value; therefore, EPA 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 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. For this reason, EPA is proposing and seeks comment on the choice to use a larger percentile for the weekly average limitation than the one used for the monthly average limitation. Consequently, EPA is proposing the 97th percentile as an appropriate basis for limiting average discharges on a weekly basis. EPA also considers this level of control in avoiding extreme weekly average discharges to be possible for airports using the model technology.

4. Rationale for Proposing 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 circumstances associated with monitoring during the deicing season. In this situation, the weekly average limitation would apply to every week that the treatment system operates during the deicing season.

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 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.

A weekly average limitation preserves EPA's intent for an additional restriction beyond the daily maximum limitation that supports EPA's objective of having airports control their average discharges at the long-term average. EPA is proposing and soliciting comment on use of a weekly average instead of a monthly average limitation because it appears to be a better fit for this industry from a monitoring perspective. However, two factors may warrant another approach in the final rule. First, a week may be too short a period to ensure that airports will optimize their systems appropriately over a longer period to achieve the long-term average. Second, the industry and permit writers are unlikely to have experience with weekly average limitations and may prefer other alternatives. Other approaches may include the monthly average limitation and/or the annual average limitation sometimes used for intermittent dischargers in other industries. For example, for the Pulp, Paper and Paperboard Category (40 CFR Part 430), EPA promulgated an annual average limitation that was set equal to the value of the long-term average derived from the data used to develop the daily maximum and monthly average limitations for continuous dischargers. (It does not have an allowance for variability.) EPA solicits comment on whether weekly average limitations, monthly average limitations or some other approach would be appropriate to ensure that airports have well-operated, maintained, and controlled treatment systems that discharge at a level consistent with the long-term average.

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

EPA believes that it 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 COD, EPA is not proposing a weekly ammonia effluent limitation. The technology basis for the COD effluent limitations would operate throughout the deicing season with continuous discharges allowing for weekly monitoring. In contrast, urea is applied to airfield pavement as needed, and discharges would occur for a short time after the initial application, as the urea works its way through the stormwater collection and any associated treatment system that may be present. Most airports would have 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. In developing the average limitations, this assumed monitoring frequency is used in the statistical calculations. Although EPA has concerns about establishing average limitations on a national basis, a permit authority may choose to establish weekly or monthly average limitations for a specific airport, and would presumably assume a monitoring frequency based upon local 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 runoff. Thus, it is possible that no airports will be subject to any limitation on ammonia discharges. For the final rule, after reviewing any supplementary information and comments, EPA may reevaluate whether weekly and/or monthly average limitations are necessary for proper control of ammonia.

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 proposed daily maximum limitation for COD, EPA used the nonparametric method to derive a 99th percentile of the more than 1200 daily measurements for each unit, and then set the proposed 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).

For the weekly average limitation of COD, EPA first calculated, for each unit, the arithmetic average of the measurements observed during each week, excluding weekends (to be consistent with the assumed monitoring costs, although permit authorities may specify different monitoring requirements). EPA then used the nonparametric method to derive a 97th percentile of the more than 200 weekly averages for each unit, and set the proposed limitation equal to the median of the two 97th percentile estimates, or 154 mg/L.

For comparison purposes, EPA tentatively estimated 112 mg/L as the 95th percentile of the monthly averages using a statistical model based upon the lognormal distribution. If EPA were to establish a monthly average limitation, it would examine the statistical properties of the data to determine the appropriate model and statistical assumptions.

For ammonia, EPA used a parametric approach in estimating the 99th percentile based upon the data collected during EPA's 4-day sampling episode. The calculations assume the ammonia concentrations can be modeled by a lognormal distribution. EPA's selection of parametric methods, such as the lognormal distribution, 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 proposed 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 are more closely interrelated than measurements taken farther apart in time. The adjusted variance then better reflects the underlying variability that would be present if the data were

collected over a longer period. For comparison purposes, EPA estimated values of 9.75 and 6.98 mg/L for the weekly average limitation and monthly average limitation.

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 the treatment system to achieve the long-term average that it derived for the model technology. Thus, a well-operated and designed system will be capable of complying with the proposed limitations.

For COD, EPA recommends that airports target treatment systems to achieve the long-term average value of 41 mg/L, which is the median of the 50th percentiles, of 37 and 45 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 6.6. (EPA usually refers to this allowance as the “variability factor.”) In other words, the daily maximum limitation of 271 mg/L is about seven times greater than the long-term average achievable by the model technology. The weekly variability factor is 3.8.

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 tha

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