[Federal Register: August 28, 2009 (Volume 74, Number 166)]
[Proposed Rules]
[Page 44675-44718]
[DOCID:fr28au09-28]

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Part V

Environmental Protection Agency

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40 CFR Part 449

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

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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.

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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<EMAIL_ADDRESS>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<PHONE_NUMBER>.
    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<PHONE_NUMBER>, and the
telephone number for the Water Docket is<PHONE_NUMBER>.

FOR FURTHER INFORMATION CONTACT: Eric Strassler, Engineering and
Analysis Division, telephone:<PHONE_NUMBER>; e-mail:
<EMAIL_ADDRESS>or Brian D'Amico, Engineering and Analysis
Division, telephone:<PHONE_NUMBER>; e-mail<EMAIL_ADDRESS>
SUPPLEMENTARY INFORMATION:

Regulated Entities

    Entities potentially regulated by this action include:

------------------------------------------------------------------------
                                                          North American
                                   Example of regulated      Industry
            Category                      entity          Classification
                                                            System Code
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Industry.......................  Primary airports with         481, 4881
                                  over 1,000 annual jet
                                  departures that
                                  conduct deicing
                                  operations.
------------------------------------------------------------------------

    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 Sec.  449.01 and the definitions in
Sec.  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<PHONE_NUMBER>, 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
(BOD5), chemical oxygen demand (COD), ammonia and pH;
     If the average of the four monitoring values for any
parameter exceeds its benchmark, implement additional control measures
where feasible, and continue monitoring;
     Conduct an annual site inspection during the deicing
season, and during periods of actual deicing operations if possible;
and routine facility inspections at least monthly during the deicing
season.
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
(BOD5), total suspended solids (TSS), fecal coliform, pH,
and any additional pollutants defined by the Administrator as
conventional. The Administrator designated oil and grease as an
additional conventional pollutant on July 30, 1979 (44 FR 44501; 40 CFR
401.16).
3. Best Available Technology Economically Achievable (BAT)
    BAT represents the second level of stringency for controlling
direct discharge of toxic and nonconventional pollutants. In general,
BAT effluent limitation guidelines represent the best economically
achievable performance of facilities in the industrial subcategory or
category. The 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
----------------------------------------------------------------------------------------------------------------
                                                                        Technical components
                                                   -------------------------------------------------------------
    Regulatory level          Technology basis       Airports > 1,000 annual jet    Airports > 1,000 annual jet
                                                       departures and >= 10,000       departures and < 10,000
                                                          annual departures              annual departures
----------------------------------------------------------------------------------------------------------------
BAT.....................  1. 60% or 20% ADF         1. Capture 60% of available    1. Certify use of non-urea-
                           capture.                  ADF (for airports having >=    based pavement deicers or
                                                     460,000 gal. ADF usage) or     Meet effluent limit for
                                                     capture 20% (for airports <    ammonia.
                                                     460,000 gal. ADF usage).
                          2. Biological treatment.  2. Treat wastewater to meet
                                                     effluent limit for chemical
                                                     oxygen demand (COD).
                          3. Pavement deicer        3. Certify use of non-urea-
                           product substitution.     based pavement deicers or
                                                     Meet effluent limit for
                                                     ammonia.
NSPS....................  1. 60% ADF capture......  1. Capture 60% of available    1. Certify use of non-urea-
                                                     ADF.                           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        3. Certify use of non-urea-
                           product substitution.     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.

[GRAPHIC] [TIFF OMITTED] TP28AU09.006

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[deg]
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[deg] 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\+\), BOD5
and COD load as the acetate or formate ion degrades into carbon dioxide
(CO2) and water. Pavement deicers containing urea will
degrade to ammonia, and generate BOD5 and COD load as well.
    Most of EPA's 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
------------------------------------------------------------------------
                                                              Number of
                   Collection technology                       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 BOD5, over 97 percent of COD, and over 99 percent
of propylene glycol from the wastestream. This reduced the
BOD5 and COD loads discharged to receiving waters by over 98
and 97 percent, respectively. Two airports in the United States use the
AFB technology: Albany 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 [deg]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 BOD5, 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 BOD5, 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 BOD5 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 BOD5, 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 BOD5 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 BOD5 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 BOD5 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 BOD5
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
------------------------------------------------------------------------
               Requirement (applies
                to primary airports       Estimated
   Option      with more than 1,000      airports in    Technology basis
              annual jet departures)        scope
------------------------------------------------------------------------
1...........  20% ADF Capture         110.............  Glycol recovery
               (Airports w/10,000 or                     vehicle (GRV).
               more annual
               departures).

2...........  40% ADF Capture         110.............  Plug & Pump.
               (Airports w/10,000 or
               more annual
               departures).
3...........  60% ADF Capture         110 (14 @ 60% +   Centralized
               (Airports w/460,000     96 @ 20%).        Deicing Pad +
               gals. or more annual                      GRV.
               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).
4...........  60% ADF Capture         218 (14 @ 60% +   Centralized
               (Airports w/460,000     204 @ 20%).       Deicing Pad +
               gals. or more ADF                         GRV.
               usage) + 20% ADF
               Capture (Airports w/
               1,000 or more jet
               departures).
------------------------------------------------------------------------
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 Sec.  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 Sec.
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'' (Sec. Sec.  122.2 and
122.29(a)(2)) and because a new runway is ``substantially independent
of an existing source at the same site'' (Sec.  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 Sec.
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
Sec.  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
BOD5 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 BOD5 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