[Federal Register Volume 91, Number 95 (Monday, May 18, 2026)]
[Proposed Rules]
[Pages 28487-28514]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2026-09895]
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 423
[EPA-HQ-OW-2009-0819; FRL-8794.2-01-OW]
RIN 2040-AG41
Effluent Limitations Guidelines and Standards for the Steam
Electric Power Generating Point Source Category--Unmanaged Combustion
Residual Leachate
AGENCY: Environmental Protection Agency (EPA).
ACTION: Proposed rule.
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SUMMARY: The U.S. Environmental Protection Agency (EPA or Agency) is
proposing a Clean Water Act (CWA) regulation to revise the technology-
based effluent limitations guidelines and standards (ELGs) promulgated
in the 2024 ``Supplemental Effluent Limitations Guidelines and
Standards for the Steam Electric Power Generating Point Source
Category'' (2024 ELG). This proposed regulation for the steam electric
power generating point source category applies to unmanaged combustion
residual leachate (CRL) at existing sources and is estimated to reduce
costs by $446 to $1,090 million dollars annually at a 3 percent
discount rate.
DATES: Comments must be received on or before June 17, 2026.
ADDRESSES: You may send comments, identified by Docket ID No. EPA-HQ-
OW-2009-0819, by any of the following methods:
Federal eRulemaking Portal: https://www.regulations.gov/ (our
preferred method). Follow the online instructions for submitting
comments.
Email: [email protected]. Include Docket ID No. EPA-HQ-OW-2009-0819
in the subject line of the message.
Mail: U.S. Environmental Protection Agency, EPA Docket Center,
Office of Water, Office of Science and Technology, Docket, Mail Code
28221T, 1200 Pennsylvania Avenue NW, Washington, DC 20460.
Hand Delivery or Courier: EPA Docket Center, WJC West Building,
Room 3334, 1301 Constitution Avenue NW, Washington, DC 20004. The
Docket Center's hours of operations are 8:30 a.m. to 4:30 p.m., Monday
through Friday (except Federal Holidays).
Instructions: All submissions received must include the Docket ID
No. for this rulemaking. Comments received may be posted without change
to https://www.regulations.gov, including personal information
provided. For detailed instructions on sending comments and additional
information on the rulemaking process, see the ``Public Participation''
heading of the SUPPLEMENTARY INFORMATION section of this document.
FOR FURTHER INFORMATION CONTACT: Dr. Paul Shriner, Engineering and
Analysis Division Office of Water (Mail Code 4303T), Environmental
Protection Agency, 1200 Pennsylvania Avenue NW, Washington, DC 20460;
telephone number: 202-566-1076; email address: [email protected].
Information about the Steam Electric Effluent Limitations Guidelines
and Standards (ELGs) is available online at https://www.epa.gov/eg/steam-electric-power-generating-effluent-guidelines.
SUPPLEMENTARY INFORMATION:
Table of Contents
I. Executive Summary
II. Does this action apply to me?
III. What is the Agency's authority for taking this action?
IV. Background
A. Clean Water Act
B. Relevant Effluent Guidelines
1. Best Practicable Control Technology Currently Available
2. Best Available Technology Economically Achievable
3. Best Professional Judgment
C. 2015 Steam Electric ELG
1. Summary of the 2015 ELG
2. Vacatur of Limitations Applicable to CRL and Legacy
Wastewater
D. 2020 Steam Electric Reconsideration Rule
1. Summary of the 2020 ELG
2. 2020 ELG Litigation
E. 2024 Supplemental Steam Electric Rule
1. Summary of 2024 ELG
2. 2024 ELG Litigation
3. Administrative Petitions for Reconsideration of the 2024 ELG
and Related Requests
F. 2025 Steam Electric Deadlines Extension Rule
1. Summary of 2025 Steam Electric Deadline Extensions Rule
2. 2025 Deadline Extensions Rule Litigation
G. Disposal of Coal Combustion Residuals From Electric Utilities
Final Rule
1. 2015 CCR Rule
2. 2020 Holistic CCR Rules
3. 2024 Legacy CCR Rule
V. Steam Electric Power Generating Industry Description
A. General Description of Industry
B. What is unmanaged combustion residuals leachate?
C. 2024 Baseline Was Likely Incorrect and Has Also Significantly
Changed
D. The Unique Nature of Unmanaged CRL
E. Control and Treatment Technologies
VI. Proposed Rule
A. Description of the Options
B. Rationale for the Proposed Rule
1. Rationale for Not Proposing Option 3 as BAT
2. Rationale for Not Proposing Option 2 as BAT
3. Rationale for Proposing Option 1 as the Preferred Option for
BAT
VII. What are the benefits, costs and economic impacts of the
proposed revisions?
A. Introduction and Overview
B. Method for Estimating Compliance Costs
C. Method for Estimating Economic Impacts
D. Estimated Annual Costs of the Proposed Regulatory Options/
Scenarios
E. Economic Achievability
F. Impacts on Residential Electricity Prices
G. Benefit-Cost Analysis
VIII. Pollutant Loadings
A. Unmanaged Combustion Residual Leachate
B. Summary of Incremental Changes of Pollutant Loadings
IX. Non-Water Quality Environmental Impacts
A. Energy Requirements
B. Air Pollution
C. Solid Waste Generation
D. Changes in Water Use
X. Environmental Assessment and Benefits
A. Introduction
B. Updates to the Environmental Assessment Methodology
C. Outputs From the Environmental Assessment
D. Benefits
XI. Implementation
A. Continued Implementation of Existing Limitations and
Standards
B. Implementation of New Limitations and Standards
C. Reporting and Recordkeeping Requirements
D. Site-Specific Water Quality-Based Effluent Limitations
E. Severability
XII. Data Request
XIII. Statutory and Executive Order Reviews
A. Executive Order 12866: Regulatory Planning and Review and
Executive Order 13563: Improving Regulation and Regulatory Review
B. Executive Order 14192: Unleashing Prosperity Through
Deregulation
C. Paperwork Reduction Act (PRA)
D. Regulatory Flexibility Act (RFA)
E. Unfunded Mandates Reform Act (UMRA)
F. Executive Order 13132: Federalism
G. Executive Order 13175: Consultation and Coordination With
Indian Tribal Governments
H. Executive Order 13045: Protection of Children From
Environmental Health Risks and Safety Risks
I. Executive Order 13211: Actions Concerning Regulations That
Significantly Affect Energy Supply, Distribution, or Use
J. National Technology Transfer and Advancement Act (NTTAA)
[[Page 28488]]
I. Executive Summary
The EPA is proposing this rule to update requirements that apply to
wastewater discharges from steam electric power plants, particularly
coal-fired power plants. In 2024, the EPA finalized revisions to the
technology-based effluent limitations guidelines and standards (ELGs)
for the steam electric power generating point source category that
imposed stringent requirements on certain wastewaters from these
plants, requiring the facilities not to discharge any pollutants or
imposing non-zero numerical limitations on pollutants from certain
types of industrial wastewaters (89 FR 40198, May 9, 2024) (hereinafter
the ``2024 ELG'').
Subsequent to promulgation of the 2024 ELG, the EPA became aware of
new information regarding the retirement status of a number of plants
as well as updates some dischargers have made to their wastewater
treatment in place. The EPA also identified a flaw in the baseline
utilized by the 2024 ELG as it pertains to unmanaged combustion
residual leachate (CRL) by omitting capture and pumping costs, an
important component of the technology basis. The EPA's revised analysis
presented shows these costs imposed by the 2024 ELG are not
insignificant. As such, the EPA is concerned about other cost elements
that could be impacted by the Agency's assumptions that 100 percent of
the contaminated groundwater could in fact be captured and treated, and
the Agency's assumptions regarding power plants' ability to achieve the
2024 ELG numerical limitations. The EPA is also concerned that the 2024
ELG may not have fully accounted for the lack of revenue generated by
closed utilities, and thus the lack of funding available, to implement
treatment in an economically achievable way. In addition, despite the
EPA previously acknowledging very little data that characterizes
groundwater laden with unmanaged CRL, commenters have not provided any
additional data to help characterize this wastestream. In light of the
increasing costs, the EPA is now reconsidering the characterization
data gap and how it may impact costs.
In the time following the promulgation of the 2024 ELG, the U.S.
has experienced extraordinary increases in energy demand, decreases in
energy reserves, difficulties in transmission across the electricity
grid, increases in energy prices, and heightened concerns about energy
reliability. Consequently, in March 2025, EPA Administrator Zeldin
announced that the Agency would reconsider 2024 pollution limitations
for coal-fired power plants. The EPA identified additional information
that showed that, due to supply chain logistical challenges as well as
the unique characteristics of each plant's operational needs, the
deadlines to comply with the 2024 ELG were infeasible and impractical
on a nationwide basis. In late 2025, the EPA issued a final rule that,
in part, extended compliance deadlines for many of the zero-discharge
requirements in the 2024 ELG and the deadline for facilities to submit
a Notice of Planned Participation for the permanent cessation of coal
combustion. These compliance deadline extensions gave utilities and
permitting authorities the flexibilities needed to ensure affordable
and reliable power (90 FR 61328; December 31, 2025) (hereinafter the
``2025 Deadline Extensions Rule''). The 2025 Deadline Extensions Rule
did not change the underlying technology bases for the 2024 effluent
limitations based on BAT. Subsequent to the 2025 Deadline Extensions
Rule, the EPA intended to further evaluate data obtained after the
promulgation of the 2024 ELG, as well as data submitted during the 2025
Deadline Extensions Rule public comment period, to determine if further
rulemaking for reconsidering the BAT requirements imposed by the 2024
ELG is appropriate.
This proposed rulemaking continues to advance the Trump
Administration's commitment to unleash American energy by revising the
existing Steam Electric ELG for unmanaged combustion residual leachate
to ensure the 2024 ELG does not financially cripple this critical
industry or contribute to burdensome energy costs for American
families. CRL is leachate from landfills or surface impoundments
(collectively called waste management units) that contain coal
combustion residuals (CCR). Leachate is composed of liquid, including
any suspended or dissolved constituents in the liquid, that has
percolated through waste or other materials emplaced in a landfill or
that passes through the surface impoundment's containment structure
(e.g., bottom, liner, dikes, berms). CRL is typically managed using a
liner and leachate-collection system. The primary function of the
leachate-collection system is to collect and convey leachate out of the
landfill unit and to control the depth of the leachate above the liner.
In contrast, many CCR landfills and surface impoundments also have
unmanaged CRL, which is distinct from managed CRL. Unmanaged CRL is
leachate that is not captured from a leachate-collection system and
instead percolates out of the landfill or impoundment unit and into the
subsurface. These CRL wastestreams are defined in the current Steam
Electric ELGs, and the EPA is using the same definition of unmanaged
CRL as it did in the 2024 ELG.
Unmanaged CRL is a complex wastestream from coal-fired power
plants. The extent to which unmanaged CRL exists at any given plant is
variable and not well documented, the characterization of the unmanaged
leachate significantly varies by location, and unmanaged leachate
discharges can fluctuate rapidly and extensively. Additionally,
unmanaged CRL is one of the more costly wastestreams for coal-fired
power plants to manage effectively because, in addition to the
treatment technologies themselves that must be sized to accommodate a
large volume of flow, a potentially complex and costly system for
extracting large volumes \1\ of CRL laden wastewater must be installed.
This proposal describes the challenges addressing unmanaged CRL, offers
a range of regulatory options based on different known technologies,
and solicits comment and data on the availability, performance,
feasibility, and costs of each proposed option. This proposal only
pertains to unmanaged CRL and does not include any proposed changes to
managed CRL requirements imposed by the 2024 ELG.
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\1\ As discussed later in this preamble, coal ash impoundments
containing CRL are typically more than 50 acres in size and more
than 20 feet deep. A system for collecting CRL laden groundwater for
treatment would need to be sized accordingly.
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II. Does this action apply to me?
Entities potentially regulated by this action include:
[[Page 28489]]
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North American Industry
Category Example of regulated entity Classification System
(NAICS) Code
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Industry........................................ Electric Power Generation 22111
Facilities--Electric Power
Generation.
Electric Power Generation 221112
Facilities--Fossil Fuel Electric
Power Generation.
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This table is not intended to be exhaustive but rather provides a
guide for readers regarding entities likely to be regulated by this
action. This table includes the types of entities that the EPA is aware
could potentially be regulated by this action. Other types of entities
not included could also be regulated. To determine whether your entity
is regulated by this action, you should carefully examine the
applicability criteria found in 40 CFR 423.10 (Applicability). If you
have questions regarding the applicability of this action to a
particular entity, consult the person listed in the FOR FURTHER
INFORMATION CONTACT section.
III. What is the Agency's authority for taking this action?
The authority for this rulemaking is the Federal Water Pollution
Control Act, 33 U.S.C. 1251 et seq., including the Clean Water Act
(CWA) sections 301, 304(b), 304(g), 307, 402(a), and 501(a); 33 U.S.C.
1311, 1314(b), 1314(g), 1317, 1342(a), and 1361(a).
Unless otherwise provided by law, agencies may reconsider past
decisions and revise, replace or repeal a decision so long as the
agency provides a reasoned explanation and considers significant
reliance interests. FCC v. Fox Television Stations, Inc., 556 U.S. 502,
515 (2009); Motor Vehicle Mfrs. Ass'n v. State Farm Mut. Auto. Ins.
Co., 463 U.S. 29, 42 (1983); see also Nat'l Ass'n of Home Builders v.
EPA, 682 F.3d 1032, 1038 & 1043 (D.C. Cir. 2012) (a revised rulemaking
based ``on a reevaluation of which policy would be better in light of
the facts'' is ``well within an agency's discretion,'' and ``[a] change
in administration brought about by the people casting their votes is a
perfectly reasonable basis for an executive agency's reappraisal'' of
its policy choices) (citations omitted). As discussed in section I of
this preamble above and as described in further detail below, the EPA
is reconsidering the 2024 ELG for unmanaged CRL, in part, because the
EPA is concerned that the 2024 ELG may not have relied on appropriately
up-to-date and complete data in reaching its decision to regulate
unmanaged CRL using technology that the EPA now proposes, based upon
new and more complete information, is economically unachievable.
IV. Background
A. Clean Water Act
Congress passed the Federal Water Pollution Control Act Amendments
of 1972, also known as the 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
direct discharge of pollutants from a point source to waters of the
United States (WOTUS), except as authorized under the CWA. Under CWA
section 402, discharges may be authorized through a National Pollutant
Discharge Elimination System (NPDES) permit. 33 U.S.C. 1342. The CWA
also authorizes the EPA to establish nationally applicable, technology-
based ELGs for discharges from different categories of point sources,
such as industrial, commercial, and public sources. 33 U.S.C. 1311,
1314.
Direct dischargers (i.e., those discharging directly to WOTUS
rather than through publicly owned treatment works, or POTWs) must
comply with effluent limitations in NPDES permits.\2\ Discharges that
flow through groundwater before reaching surface waters that are the
``functional equivalent'' of a direct discharge from a point source to
a WOTUS are considered direct discharges and must comply with effluent
limitations in NPDES permits. See Cnty. of Maui v. Haw. Wildlife Fund,
590 U.S. 165 (2020). Based upon the applicable effluent limitations
guidelines (ELGs) promulgated by the EPA, numeric limitations in NPDES
permits are implemented through discharger-specific technology-based
effluent limitations (TBELs). CWA sections 301 and 304, 33 U.S.C. 1311
and 1314. If an ELG promulgated by the EPA is inapplicable, then the
permitting authority sets TBELs based on its best professional judgment
(BPJ). CWA section 402(a)(1)(B), 33 U.S.C. 1342(a)(1)(B); 40 CFR
125.3(c).
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\2\ Indirect dischargers that discharge through POTWs must
comply with pretreatment standards.
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The EPA establishes ELGs by regulation for categories of point
source dischargers that are based on the degree of control that can be
achieved using various levels of pollution control technology. The EPA
promulgates national ELGs for major industrial categories for three
classes of pollutants: (1) conventional pollutants (i.e., total
suspended solids or TSS, oil and grease, biochemical oxygen demand or
BOD5, fecal coliform, and pH), as outlined in CWA section
304(a)(4) and 40 CFR 401.16; (2) toxic pollutants (e.g., toxic metals
such as arsenic, mercury, selenium, and chromium; toxic organic
pollutants such as benzene, benzo-a-pyrene, phenol, and naphthalene),
as outlined in CWA section 307(a), 40 CFR 401.15 and 40 CFR part 423
appendix A; and (3) nonconventional pollutants, which are those
pollutants that are not categorized as conventional or toxic (e.g.,
ammonia-N, phosphorus, and total dissolved solids or TDS).
B. Relevant Effluent Guidelines
The EPA develops ELGs that are technology-based regulations for a
category of dischargers and are not based on a discharge's effect on
water quality. See, e.g., Sw. Elec. Power Co. v. EPA, 920 F.3d 999,
1005 (5th Cir. 2019) (``[T]he Administrator must require industry,
regardless of a discharge's effect on water quality, to employ defined
levels of technology to meet effluent limitations.'') (citations and
internal quotations omitted). The EPA bases these regulations, in part,
on the performance of control and treatment technologies.
There are several TBELs that may apply to a given discharger when
issued a NPDES permit under the CWA: four types of standards applicable
to direct dischargers, two types of standards applicable to indirect
dischargers, and a default site-specific approach. The TBELs relevant
to this rulemaking are described in detail below.
1. Best Practicable Control Technology Currently Available
Traditionally, the EPA establishes effluent limitations based on
best practicable control technology (BPT) by
[[Page 28490]]
considering the average of the best performances of facilities within
the industry, grouped to reflect various ages, sizes, processes, or
other common characteristics. The EPA may promulgate ELGs establishing
BPT-based limitations for conventional, toxic, and nonconventional
pollutants. In specifying BPT, the EPA looks at a number of factors.
The EPA first considers the cost of achieving effluent reductions in
relation to the effluent reduction benefits. The Agency also considers
the age of equipment and facilities, the processes employed,
engineering aspects of the control technologies, any required process
changes, non-water quality environmental impacts (NWQEIs, including
energy requirements), and such other factors as the Administrator deems
appropriate. See CWA section 304(b)(1)(B), 33 U.S.C. 1314(b)(1)(B).
2. Best Available Technology Economically Achievable
BAT represents the second level of stringency for controlling
direct discharge of toxic and nonconventional pollutants, after BPT.
The U.S. Court of Appeals for the Fifth Circuit has referred to this as
the CWA's ``gold standard'' for controlling discharges from existing
sources. Sw. Elec. Power Co., 920 F.3d at 1003. In general, BAT
represents the best available, economically achievable performance of
facilities in the industrial subcategory or category. Consistent with
the statutory language, the EPA considers technological availability
and economic achievability in determining what level of control
represents BAT. CWA section 301(b)(2)(A), 33 U.S.C. 1311(b)(2)(A).
Other statutory factors that the EPA considers in assessing BAT are the
cost of achieving BAT effluent reductions, the age of equipment and
facilities involved, the process employed, potential process changes,
NWQEIs (including energy requirements), and such other factors as the
Administrator deems appropriate. CWA section 304(b)(2)(B), 33 U.S.C.
1314(b)(2)(B). The Agency retains considerable discretion in assigning
the weight to be accorded each factor. Weyerhaeuser Co. v. Costle, 590
F.2d 1011, 1045 (D.C. Cir. 1978). This is especially true for EPA's
consideration of NWQEIs. BP Expl. & Oil, Inc. v. EPA, 66 F.3d 784, 801-
02 (6th Cir. 1995). Historically, the EPA has generally determined
economic achievability on the basis of the effect of the cost of
compliance with BAT limitations on overall industry and subcategory
financial conditions. BAT reflects the highest performance in the
industry and may reflect a higher level of performance than is
currently being achieved in the industry as a whole. See, e.g., Sw.
Elec. Power Co., 920 F.3d at 1006; Am. Paper Inst. v. Train, 543 F.2d
328, 353 (D.C. Cir. 1976); Am. Frozen Food Inst. v. Train, 539 F.2d
107, 132 (D.C. Cir. 1976). Under this approach, BAT may be based upon
process changes or internal controls, even when these technologies are
not widespread industry practice. See Id. at 132, 140; Reynolds Metals
Co. v. EPA, 760 F.2d 549, 562 (4th Cir. 1985); Cal. & Hawaiian Sugar
Co. v. EPA, 553 F.2d 280, 285-88 (2d Cir. 1977). Courts have previously
endorsed this approach. See Kennecott v. EPA, 780 F.2d 445, 448 (4th
Cir. 1985); see also Sw. Elec. Power Co., 920 F.3d at 1031.
3. Best Professional Judgment
In CWA section 301 and the EPA's implementing regulation at 40 CFR
125.3(a) indicate that technology-based treatment requirements under
section 301(b) represent the minimum level of control that must be
included in an NPDES permit. See 33 U.S.C. 1311. Where EPA has not
promulgated a BPT or BAT-based limitation applicable to a category or
subcategory of dischargers discharging directly into a WOTUS, or where
such an EPA-promulgated ELG has been remanded by a court or withdrawn
by the EPA, the EPA has provided by regulation that such treatment
requirements are to be established by the NPDES permitting authority on
a case-by-case basis using the permit writer's BPJ. Under the EPA's
regulations, these case-by-case TBELs are developed by permit writers
on the basis that CWA section 402(a)(1) authorizes the EPA
Administrator to issue a permit that will meet either: all applicable
requirements developed under the authority of other sections of the CWA
(e.g., technology-based treatment standards, water quality standards,
ocean discharge criteria) or, before taking the necessary implementing
actions related to those requirements, ``such conditions as the
Administrator determines are necessary to carry out the provisions of
this Act.'' 33 U.S.C. 1342(a)(1). The regulation at 40 CFR 125.3(c)(2)
cites this section of the CWA, stating that technology-based treatment
requirements may be imposed in a permit ``on a case-by-case basis under
section 402(a)(1) of the Act, to the extent that EPA-promulgated
effluent limitations are inapplicable.'' Furthermore, 40 CFR
125.3(c)(3) states that ``[w]here promulgated effluent limitations
guidelines only apply to certain aspects of the discharger's operation,
or to certain pollutants, other aspects or activities are subject to
regulation on a case-by-case basis in order to carry out the provisions
of the Act.'' The factors considered by the permit writer are the same
as those that the EPA considers when establishing effluent guidelines.
See 40 CFR 125.3(d)(1)-( )-3).
C. 2015 Steam Electric ELG
1. Summary of the 2015 ELG
On November 3, 2015, the EPA promulgated a rule revising the
regulations for the steam electric power generating point source
category at 40 CFR part 423. 80 FR 67838 (2015 ELG). The 2015 ELG set
the first Federal limitations on the levels of toxic pollutants (e.g.,
arsenic) and nutrients (e.g., nitrogen) that can be discharged in the
steam electric power generating industry's largest sources of
wastewater based on technology improvements in the industry over the
preceding three decades. Before the 2015 ELG, regulations for the
industry were last updated in 1982 and contained only limitations on
TSS and oil and grease for the industry's wastestreams with the largest
pollutant loadings.
2. Vacatur of Limitations Applicable to CRL and Legacy Wastewater
Electric utilities, environmental groups, and drinking water
utilities filed seven petitions for review of the 2015 ELG in various
circuit courts. The petitions were consolidated in the U.S. Court of
Appeals for the Fifth Circuit as Southwestern Electric Power Co. v.
EPA, Case No. 15-60821. In early 2017, the EPA received two
administrative petitions to reconsider the 2015 ELG: one from the
Utility Water Act Group (UWAG) and one from the Small Business
Administration.
On August 11, 2017, the EPA announced a rulemaking to potentially
revise the new, more stringent BAT effluent limitations and
pretreatment standards for existing sources (PSES) in the 2015 ELG that
apply to flue gas desulfurization wastewater and bottom ash transport
water. The Fifth Circuit subsequently granted the EPA's request to
sever and hold in abeyance petitioners' claims related to those
limitations and standards, and those claims are still in abeyance. With
respect to the remaining claims related to limitations applicable to
legacy wastewater and CRL, the court issued a decision in 2019 vacating
those limitations as arbitrary and capricious under the Administrative
Procedure Act and unlawful under the CWA, respectively. Sw. Elec. Power
Co., 920 F.3d at 1033. In the case of CRL, the court held that the
EPA's setting of BAT
[[Page 28491]]
limitations equal to BPT limitations was an impermissible conflation of
the two standards, which are supposed to be progressively more
stringent, and that the EPA's rationale was not authorized by the
statutory factors for determining BAT. Id. at 1026. After the court's
decision, the EPA announced plans to address the vacated limitations in
a later action.
D. 2020 Steam Electric Reconsideration Rule
1. Summary of the 2020 ELG
On October 13, 2020, the EPA promulgated the Steam Electric
Reconsideration Rule, 85 FR 64650 (2020 ELG). The 2020 ELG changed the
technology basis for two wastestreams (FGD wastewater and bottom ash
transport water) resulting in revised limitations, created three new
subcategories, and revised the technology basis for the voluntary
incentives program. The 2020 ELG required most steam electric
facilities to comply with the revised effluent limitations ``as soon as
possible'' after October 13, 2021, but no later than December 31, 2025.
NPDES permitting authorities established the particular applicability
date(s) of the new limitations within that range for each facility
(except for indirect dischargers) at the time they issued the
facility's NPDES permit.
2. 2020 ELG Litigation
Environmental groups filed two petitions for review of the 2020
rule, which were consolidated in the U.S. Court of Appeals for the
Fourth Circuit on November 19, 2020, as Appalachian Voices, et al. v.
EPA, No. 20-2187. An industry trade group and certain energy companies
moved to intervene in the litigation, which the court authorized on
December 3, 2020. On April 8, 2022, the court granted the EPA's motion
to place the case into abeyance as a result of a new rulemaking
announced in July 2021. The case remains in abeyance.
E. 2024 Supplemental Steam Electric Rule
1. Summary of 2024 ELG
On May 9, 2024, as part of a ``suite of final rules'' imposing new
requirements on the power generation sector, the EPA promulgated the
Steam Electric Supplemental Rule (89 FR 40198) (2024 ELG). This
revision of the regulations at 40 CFR part 423 established a zero-
discharge limitation for three wastewaters generated at steam electric
power plants: flue gas desulfurization wastewater, bottom ash transport
water, and CRL. The 2024 ELG also established non-zero numeric
discharge limitations on mercury and arsenic from unmanaged CRL, which
is a distinct subset of CRL defined in the ELG to include discharges of
CRL that the permitting authority determines are the functional
equivalent of a direct discharge to a WOTUS through groundwater or
discharges of CRL that have leached from a waste management unit into
the subsurface and mixed with groundwater before being captured and
pumped to the surface for discharge directly to a WOTUS. These mercury
and arsenic limitations also applied to a fourth wastestream called
legacy wastewater, which is typically discharged from surface
impoundments during the closure process, where those surface
impoundments had not commenced closure under the EPA's coal combustion
residuals (CCR) regulations under the Resource Conservation and
Recovery Act as of the effective date of the 2024 ELG.
As a general matter, the Clean Water Act addresses instances in
which there are discharges to the jurisdictional waters of the United
States (``jurisdictional waters'' or WOTUS). Accordingly, the proposed
Steam Electric ELG is designed to address impacts to surface waters
(i.e., a WOTUS) from a subset of leachate from coal-fired electric
generating utilities that is discharged to a WOTUS:
o discharges of CRL that are the functional equivalent of a direct
discharge to a WOTUS through groundwater; or
o discharges of CRL that have leached from a waste management unit
into the subsurface and mixed with groundwater before being captured
and pumped to the surface for discharge directly to a WOTUS.
By contrast, the CCR rule deals with the disposal units themselves
(where they are located, specific design and operating criteria,
structural stability requirements, groundwater monitoring and
corrective action, closure of the units, etc.) and primarily with their
impacts or potential impacts to groundwater.
Discharges covered by an NPDES permit are excluded from the CCR
regulations, because such discharges are not ``solid waste'' pursuant
to RCRA section 1004(27). The RCRA exclusion only applies to
``industrial discharges that are point sources subject to permits,''
i.e., to the discharges to jurisdictional waters, and not to any
activity, including groundwater releases or contaminant migration, that
occurs prior to that point. See 40 CFR 261.4(a)(2) (``This exclusion
applies only to the actual point source discharge. It does not exclude
industrial wastewaters while they are being collected, stored or
treated before discharge''). For purposes of the RCRA exclusion, EPA
considers the ``actual point source discharge'' to be the point at
which a discharge reaches the jurisdictional waters, and not in the
groundwater or otherwise prior to the jurisdictional water.
Accordingly, the CCR regulations do not apply to the unmanaged CRL
regulated under the proposed Steam Electric ELG.
However, by regulating/preventing the release of leachate to
groundwater, or requiring corrective action (remediation) of CCR
leachate in the groundwater, the CCR rule may secondarily address
impacts to surface waters that:
o would otherwise be addressed by the steam electric ELG proposal,
and/or
o fall outside of the proposal, because a permitting authority
determines the discharge(s) are not the functional equivalent of a
direct discharge to a WOTUS through groundwater, or are discharged to a
non-WOTUS.
2. 2024 ELG Litigation
A number of parties challenged the 2024 ELG in various petitions
that were consolidated before the U.S. Court of Appeals for the Eighth
Circuit as Southwestern Electric Power Co. v. EPA, No. 24-2123. Some
petitioners, in part, alleged that EPA arbitrarily inflated the costs
of the zero-discharge option for unmanaged CRL, and thus, improperly
concluded that zero-discharge technology is not achievable for the
unmanaged CRL subcategory, where that technology is available and
achievable for other types of leachate discharges. Conversely, other
petitioners alleged, in part, that that EPA acted arbitrarily and
capriciously by adopting a new subcategory for discharges of unmanaged
CRL without defining the universe of regulated entities, explaining how
the technology would apply to the vast range of circumstances involving
these kinds of discharges, or rationally determining the economic
achievability of these limitations. Following a change in
administrations, litigation in these cases has been paused while EPA
reconsiders the 2024 Rule.
3. Administrative Petitions for Reconsideration of the 2024 ELG and
Related Requests
The EPA has received two petitions for reconsideration of the 2024
ELG, one from the Edison Electric Institute (EEI) and one from UWAG.
EEI is a trade association that represents U.S. investor-owned
electric companies. On November 13, 2024, EEI
[[Page 28492]]
sent a petition to the EPA, which included recommendations to clarify
the definition of a ``closed waste management unit,'' and to clarify
that BPJ limitations continue to apply at retired plants and that new
effluent limitations for unmanaged CRL do not apply to landfills closed
by the 2024 ELGs effective date of July 8, 2024 (DCN SE11943). This
petition was updated with a supplemental letter from EEI on May 8,
2025, which reiterated recommendations for CRL applicability and
included additional recommendations relating to unmanaged CRL (DCN
SE11948).
The UWAG is a voluntary non-profit group comprised of individual
energy companies and two national trade associations of energy
companies: the National Rural Electric Cooperative Association (NRECA)
and the American Public Power Association (APPA). NRECA represents
nearly 900 local electric cooperatives across the U.S., serving 42
million people and covering 56 percent of the nation's land area. APPA
is the national service organization that represents not-for-profit
local, State, or other government-owned electric utilities. On February
21, 2025, UWAG sent the Agency a petition for rulemaking to reconsider
and repeal the 2024 ELG, as well as administratively stay the 2024 ELG
while it is in litigation (DCN SE11944). The petition requests several
reviews of the determinations underlying the 2024 ELG, including the
2024 ELG's findings with regard to unmanaged CRL. The petition further
expresses concerns related to the unique engineering challenges of
``completely intercepting and capturing any and all CRL leaks, treating
them with chemical precipitation to meet the new limit, then
discharging the CRL back . . .'' and the potentially exorbitant costs
to do so (DCN SE11944).
In addition to these two petitions, on April 25, 2025, the EPA
received a request from America's Power, a national trade association
representing the U.S. steam electric power plants and its supply chain
(DCN SE11903A1). The letter requests that the EPA repeal the zero-
discharge requirements of the 2024 ELG and return to the 2020 ELG
requirements for CRL, flue gas desulphurization wastewater, and bottom
ash transport water.
F. 2025 Steam Electric Deadline Extensions Rule
1. Summary of 2025 Deadline Extensions Rule
On December 23, 2025, the EPA announced a final rule extending
several wastewater compliance deadlines for coal-fired power plants.
The final action was published December 31, 2025 (90 FR 61328) \3\ and
provides electricity producers with more time to comply with the 2020
and 2024 ELG deadlines in light of extraordinary increases in
electricity demand associated with the resurgence of manufacturing and
the artificial intelligence (AI) and data center revolution, and as
necessary to meet the national priorities highlighted in Executive
Orders issued by President Trump (a discussion of these Executive
Orders may be found in the record (DCN SE12125).
---------------------------------------------------------------------------
\3\ After publication, the EPA became aware of post-signature
typographical errors in the published regulatory text concerning
compliance deadlines for pretreatment standards and related
reporting recordkeeping requirements in the rule. A corrections
document was published January 30, 2026, to ensure that the rule's
compliance deadlines and reporting and recordkeeping deadlines match
those in the version of the rule signed by the EPA Administrator (91
FR 4016).
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In addition to extending certain compliance deadlines related to
zero-discharge standards in the 2024 rule, new provisions in the 2025
Deadline Extensions Rule allow permitting authorities the flexibility
to extend certain compliance deadlines on a site-specific basis due,
for example, to unexpected electricity demand.
The 2025 Deadline Extension Rule did not change the effluent
limitations requirements themselves. However, during the rulemaking
process for the 2025 Deadline Extensions Rule, the EPA also requested
additional data and information on technologies, performance, and
technology-based implementation challenges related to the 2024 ELG. The
EPA stated this data would be used to inform a future rulemaking to
support practical, feasible, and on-the-ground implementations of
wastewater pollution discharge limitations.
As a result of the 2025 data call, the EPA received site-specific
performance and costs data from Santee Cooper and Longview Power LLC
(EPA-HQ-OW-2009-0819-10769 and EPA-HQ-OW-2009-0819-10702,
respectively). Both letters raised concerns that the EPA's costing
methodology in the 2024 ELG underestimated costs. The cost methodology
has been revised for this proposal.
2. 2025 Deadline Extensions Rule Litigation
Legal advocacy groups filed four petitions for review of the 2025
Deadline Extensions Rule in different U.S. Courts of Appeals.
Waterkeeper Alliance, et al. v. EPA, No. 26-128 (2d Cir.); Appalachian
Voices v. EPA, No. 26-1072 (4th Cir.); Sierra Club v. EPA, No. 26-752
(9th Cir.); Ctr. for Biological Diversity v. EPA, No. 26-426 (9th
Cir.). The petitions have been consolidated in the U.S. Court of
Appeals for the Second Circuit, and the litigation is ongoing. In re:
Environmental Protection Agency, Effluent Limitations Guidelines and
Standards for the Steam Electric Generating Point Source Category,
Deadline Extensions, 90 FR 61328, Published on December 31, 2025, MCP
No. 199 (J.P.M.L. February 10, 2026).
G. Disposal of Coal Combustion Residuals From Electric Utilities Final
Rule
1. 2015 CCR Rule
On April 17, 2015, the EPA promulgated the Disposal of Coal
Combustion Residuals from Electric Utilities final rule (2015 CCR rule)
(80 FR 21302). This rule finalized national regulations to provide a
comprehensive set of requirements for the safe disposal of CCR,
commonly referred to as coal ash, from steam electric power plants. The
2015 CCR rule established technical requirements for CCR landfills and
surface impoundments under subtitle D of the Resource Conservation and
Recovery Act (RCRA), the Nation's primary law for regulating solid
waste.
2. 2020 Holistic CCR Rules
As a result of the D.C. Circuit Court decisions in Util. Solid
Waste Activities Grp. v. EPA, 901 F.3d 414 (D.C. Cir. 2018) (``USWAG
decision'' or ``USWAG''), and Waterkeeper All., Inc. et al. v. EPA, No.
18-1289 (D.C. Cir. filed March 13, 2019), the Administrator signed two
rules: A Holistic Approach to Closure Part A: Deadline to Initiate
Closure and Enhancing Public Access to Information (CCR Part A rule)
(85 FR 53516, August 28, 2020) on July 29, 2020, and A Holistic
Approach to Closure Part B: Alternate Liner Demonstration (CCR Part B
rule) (85 FR 72506, December 14, 2020) on October 15, 2020. The EPA
finalized several amendments to the 2015 CCR rule, which are relevant
to the management of the wastewaters covered by this proposed ELG for
unmanaged CRL because these wastewaters have historically been co-
managed with CCR in the same surface impoundments.
As explained in the 2015 and 2020 ELGs, the ELGs and CCR rules may
affect the same electric generating unit or activity at a plant.
Therefore, when the EPA finalized the 2015 ELG and 2015 CCR rule, as
well as revisions to both regulations in 2020, the Agency coordinated
the ELGs and CCR rules to
[[Page 28493]]
minimize the complexity of implementing engineering, financial, and
permitting activities. Likewise, the EPA considered the interactions of
the ELGs and CCR rules during the development of the 2024 ELG. The
EPA's analytic baseline includes the final requirements of the 2015 and
2024 ELG and CCR rules using the most recent data provided under the
2015 CCR rule reporting and recordkeeping requirements.
3. 2024 Legacy CCR Rule
Concurrently with the 2024 ELG, in a separate rulemaking the EPA
promulgated in 2024 the Legacy CCR Surface Impoundments and CCR
Management Units final rule (2024 Legacy CCR rule). The 2024 Legacy CCR
rule established regulatory requirements for inactive CCR surface
impoundments at inactive utilities (``legacy CCR surface impoundments''
or ``legacy impoundments'') (80 FR 21302; EPA-HQ-OLEM-2020-0107; FRL-
7814-04-OLEM). EPA refers to these rules collectively as the RCRA CCR
regulations throughout the remainder of this preamble.
Many of the technical requirements under the RCRA CCR regulations
also have associated internet posting requirements that help ensure
transparency and provide citizens with information about CCR units in
their state. For example, power companies were required to conduct
groundwater monitoring requirements for coal ash impoundments and to
make the data publicly available starting in March 2018. The EPA
maintains a list of the internet sites for facilities posting RCRA CCR
compliance information organized alphabetically by state (DCN SE12100).
These data cover over 300 coal plants or offsite coal ash disposal
areas, including over 750 individual coal ash ponds and landfills and
more than 4,600 groundwater monitoring wells.
V. Steam Electric Power Generating Industry Description and Processes
A. General Description of Industry
The EPA provided general descriptions of the steam electric power
generating industry in the 2015 ELG, the 2020 ELG, and the 2024 ELG.
The Agency has continued to collect information and update this
industry profile. The previous descriptions reflected the known
information about the universe of steam electric power plants and
incorporated final environmental regulations applicable at that time.
For this proposal, the EPA has revised its description of the steam
electric power generating industry (and its supporting analyses) to
incorporate changes in the plant population and corresponding waste
management units, changes in plant retirement status, and updates to
wastewater treatment in place. The analyses supporting this proposed
ELG rely on an updated baseline that incorporates these changes in the
industry and applies the numerical limitations established in the 2024
ELG. The analyses then compare the effect of each of the proposed
option requirements for unmanaged CRL to the effect on the baseline
(the industry as it exists today with the requirements of the 2024
ELG).
Of the 858 steam electric power plants in the country identified by
the EPA, only those coal-fired power plants that discharge unmanaged
CRL are expected to incur costs to comply with this proposal. Coal-
fired power plants are expected to continue discharging unmanaged CRL
from waste management units after ceasing combustion of coal. Such
plants may therefore incur costs to comply with this proposal even
after retirement.
The EPA determined that between 63 and 111 power plants may be
discharging unmanaged CRL based on whether the plants' waste management
units are unlined, not clean-closed, or undergoing corrective action.
The EPA does not expect that all these landfills and surface
impoundments are discharging unmanaged CRL; permitting authorities
would ultimately determine whether unmanaged CRL is discharged on a
site-specific case-by-case basis. Of these power plants, the EPA has
determined that at least seven power plants are currently pumping and
treating unmanaged CRL (that is mixed with groundwater) before being
captured for discharge directly to a WOTUS. The EPA did not find
evidence from available CCR monitoring reports, data reported on
installed treatment technologies to meet compliance, or solicited data
from industry that additional power plants exist that are pumping and
capturing unmanaged CRL at this time. Therefore, these seven plants
likely represent the full universe of power plants that are currently
pumping and treating unmanaged CRL, and the remaining 104 plants are
likely the upper bound number of power plants potentially discharging
unmanaged CRL in a manner that permitting authorities could determine
are the functional equivalent of a direct discharge to a WOTUS through
groundwater. The EPA is only aware of a small number of plants where
this determination has been completed. For the remaining plants, the
EPA assumes that unmanaged CRL is not currently being pumped and
captured and that treatment for unmanaged CRL has not been installed.
Therefore, the EPA expects that the costs for treating unmanaged CRL
will primarily be incurred by those plants that are determined to be
discharging unmanaged CRL as a functional equivalent of a direct
discharge, which could include all except the seven plants already
directly discharging unmanaged CRL.
B. What is unmanaged combustion residuals leachate?
Under the 2024 ELG, the EPA defined unmanaged CRL at 423.11(ff),
which the EPA is continuing to use without change in this proposal. The
2024 ELG specifies two types of unmanaged CRL that are considered
distinct from CRL and defined as: (1) discharges of CRL that the
permitting authority determines are the functional equivalent of a
direct discharge to a WOTUS through groundwater; or (2) discharges of
CRL that has leached from a waste management unit into the subsurface
and mixed with groundwater before being captured and pumped to the
surface for discharge directly to a WOTUS. This section provides a
description of how CRL and other wastewaters are generated at a coal-
fired power plant.
When a fossil-fuel plant combusts coal, the plant uses a process
called flue gas desulfurization (FGD) to remove sulfur dioxide from the
exhaust gases. Whether the flue gas desulfurization process is wet or
dry, lime or limestone is used to neutralize the acidic gases. The flue
gas desulfurization process produces gypsum as a byproduct and
generates wastewater. The pollutants in this wastewater vary primarily
depending on the coal used as the fuel source, as well as the type of
scrubber, the lime composition, and the gypsum-dewatering system. Flue
gas desulfurization wastewater is extremely well characterized as
discussed further below. After a complex treatment process, the
resulting wastewater is discharged to a WOTUS, reused on-site, or
evaporated. At plants subject to zero-discharge requirements, treated
flue gas desulfurization wastewater is sent to on-site ponds for
storage, reused within the plant for other processes such as ash
management, or evaporated with the remaining solids sent to a landfill.
CCR waste management units, including landfills and surface
impoundments, are areas used by power plants to store, treat, or
dispose of coal
[[Page 28494]]
ash and related by-products.\4\ These waste management units are
regulated under RCRA to prevent groundwater contamination. For the
purposes of this proposal, surface impoundments are areas designed to
store, treat, or dispose of coal ash and wastewater produced by power
plants when generating electricity, such as flue gas desulfurization
wastewater. The regulatory definition of surface impoundments for
purposes of RCRA may be found at 40 CFR 257.53. CCR landfills are
defined as ``an area of land or an excavation that contains CCR and
which is not a surface impoundment, an underground injection well, a
salt dome formation, a salt bed formation, an underground or surface
coal mine, or a cave.'' 40 CFR 257.53. New CCR landfills generally
include composite liners and leachate-collection systems. Both types of
waste management units can generate wastewater from moisture contained
in the material they receive and from precipitation. Wastewater from
these waste management units is monitored under various programs,
including under the RCRA CCR regulations. For the purposes of assessing
unmanaged CRL under this proposed rule the EPA finds that many waste
management units have been identified and characterized in public
reports available online (see section IV of this preamble for more
details).
---------------------------------------------------------------------------
\4\ A mixture of fly ash, bottom ash, gypsum and other coal ash
generated by-products, is also known as coal combustion residuals
(CCR).
---------------------------------------------------------------------------
In addition to the characterization of waste management units, more
than 4,600 groundwater monitoring wells have been placed around waste
management units under the RCRA CCR regulations, as well as additional
monitoring wells attributable to state or local requirements. The RCRA
CCR regulations require owners of coal ash units to monitor groundwater
for pollutants at least twice a year and annually publish accessible
reports detailing the sampling results. These reports must also
document statistical analysis, detection monitoring, or corrective
actions if levels of ground water contamination are found to be above
groundwater protection standards. Thus, the EPA considers that
groundwater in the proximity of a waste management unit should be well
characterized.
CRL is the wastewater that has passed through coal combustion
residuals, generally while the residuals are stored in waste management
units. Managed CRL that has been collected from the leachate-collection
system of a lined waste management unit is of a finite volume and has
characteristics very similar to the wastewater inputs (usually flue gas
desulfurization wastewater) to the waste management unit. By contrast,
unmanaged CRL is leachate from a waste management unit that is not
captured from a leachate-collection system and instead percolates into
the subsurface. As discussed earlier, the 2024 ELG defines two
situations in which CRL constitutes unmanaged CRL.
C. 2024 ELG Baseline Was Likely Incorrect and Has Also Significantly
Changed
Since the promulgation of the 2024 ELG, the EPA has become aware of
new information and data demonstrating (1) the existence of an energy
crisis, requiring the full use and operation of these steam electric
facilities, and (2) changes in the scope of steam electric facilities
that plan to remain operational or incur costs under the 2024 ELG.
Much of the information relied upon by the EPA during the 2024 ELG
rulemaking process did not anticipate increases in near-term energy
demand projections, while more recent information points to an
impending, extraordinary spike in energy demand that cannot currently
be satisfied by existing power generation. In 2025, the EPA documented
several generating facilities that reversed previously announced plans
to cease burning coal. Rather, in light of new rising energy demands,
these facilities have now decided to continue burning coal.
Additionally, in 2025, the Department of Energy (DOE) issued over a
dozen emergency orders to delay the closure of these coal-fired power
plants to meet energy demands. For this proposed rule, the EPA expects
that even more planned power plant retirements will be impacted and
reversed throughout 2026 as a result of the 2025 Deadline Extensions
Rule, additional DOE emergency orders will be issued to coal-fired
power plants in 2026 and beyond, and that existing coal-fired EGUs will
increase coal combusting operations to meet higher energy demands. The
EPA further expects that for these reasons, more CCR will be produced
and transported to landfills and surface impoundments, and fewer
landfills and surface impoundments will be capped or closed. Therefore,
the EPA expects discharges of unmanaged leachate to increase relative
to the amount of unmanaged CRL discharges anticipated when promulgating
the 2024 ELG.
D. The Unique Nature of Unmanaged CRL
There are certain compositional differences between and among
different unmanaged CRL originating from different dischargers and
mixed with varying types of groundwater with its own unique
characteristics that could affect treatment needs for any single
discharger. The 2024 ELG assumed that managed CRL and unmanaged CRL
would each contain the same pollutants and could be treated to the same
numeric limitations, using the same technology, at similar costs.
However, unmanaged CRL, by its very nature, permeates through
groundwater and may react with, and be affected by, the distinct
characteristics of that groundwater and any existing pollutants found
therein.
Unmanaged CRL most notably differs from managed CRL because the
wastewater has mixed with groundwater. As a result, the volume and
pollutant concentrations of unmanaged CRL are heavily influenced by the
ambient groundwater through which it passes. The groundwater may have
background levels of various pollutants that are distinct from the
leachate, but these background levels vary widely from site to site.
For example, total arsenic concentrations are frequently under 1 ug/L
in groundwater, but concentrations above 10 ug/L are found in 7 percent
of sampled wells (DCN SE12121). Indeed, the contaminated volume of
groundwater is variable, the direction of the groundwater flow may
change throughout the year, and the characterization of the groundwater
is highly site-specific. For example, in coastal plain aquifers,
saltwater intrusion drastically changes the salinity in the
groundwater, and total dissolved solids in the groundwater can range
from less than a few hundred ppm to more than several thousand ppm (DCN
SE12122).
The extent to which the pollutants that are known to be present in
CRL may change through transport in groundwater and, therefore, the
actual chemical composition of unmanaged CRL itself is unclear and may
vary considerably from any other unmanaged CRL originating from a
different discharger. The precise pollutants and concentrations in
unmanaged CRL may even vary across different landfills at the same
plant. CRL is enriched in oxyanion-forming elements such as arsenic
(As), selenium (Se), boron (B), molybdenum (Mo), and vanadium (V), as
well as major ions such as sulfate, chloride, and calcium. These
pollutants
[[Page 28495]]
are highly soluble, weakly sorbed under alkaline conditions, and are
generally persistent during subsurface transport. CRL itself is
typically alkaline and has a pH of 8-12. Interactions with surrounding
groundwaters may change the alkalinity, pH, and redox conditions of
unmanaged CRL, which may affect its pollutant concentrations. For
example, total arsenic has a median concentration of 22 ug/L in
impoundment wastewater and a median concentration of 70 ug/L in CRL
(DCN SE12123), but the median total arsenic in the CRL/groundwater mix
is unknown. The EPA does not have data documenting technology
performance with the CRL/groundwater mixture as compared to FGD
wastewater or impoundment wastewater. Several comments on the 2024 ELG
pointed out this distinction; for example, most of the total arsenic in
CRL at three American Electric Power plants is present as arsenate,
which is soluble and will not readily settle out after chemical
precipitation (EPA-HQ-OW-2009-0819-10671-A1).
Conditions of the site can also contribute to the high variability
of pollutants found in unmanaged CRL. Site-specific properties such as
site hydrology, hydraulic conductivity, groundwater plume length and
age, background contaminants present in groundwater, relative flows and
volumes of contributing groundwater, and biogeochemical properties of
soils can contribute to high variability in unmanaged CRL composition,
and batch laboratory leachate tests to characterize unmanaged CRL often
underpredict contaminant release and fail to capture long-term
geochemical processes (DCN SE12124). Field-scale monitoring and
modeling may provide site-specific hydrogeological data but vary widely
from site-to-site because of variability in local hydrological
conditions that cannot be assessed on a national level.
As a result of these pollutant and site variations, pump and
capture of unmanaged CRL from the subsurface is difficult and requires
a thorough analysis of the wastewater and the site conditions to ensure
the maximum amount of unmanaged CRL is captured. Even with site-
specific design, a pump and capture system is not guaranteed to collect
100 percent of the unmanaged CRL that has leached into groundwater.
Despite this inherent variability of unmanaged CRL, the EPA made
several assumptions about the similarities between FGD wastewater,
managed CRL, and unmanaged CRL in the 2024 ELG. In promulgating the
2015 ELG, the EPA first determined that CRL from landfills and
impoundments included similar types of pollutants as FGD wastewater,
and by extension, to waste management unit wastewaters as discussed
above. However, the EPA also determined that the pollutants in CRL
could vary more widely in concentrations and volumes compared to those
in FGD wastewater. Data from the Electric Power Research Institute
(EPRI) on untreated FGD water from 36 power plants showed variability
attributed to differences in coal composition, operational conditions
at each plant, and water circulation and reuse (DCN SE12101). During
development of the 2024 ELG, additional data obtained from EPRI showed
wastewater characteristics between CRL and FGD wastewater were similar,
but nevertheless varied across CCR waste management units due to
different types of fuels burned at the plant, duration of pond
operation, addition of bottom ash water, types of air pollution
controls employed, and ash types (DCN SE11725). The wastewater
characterization in the waste management units had the same pollutants
that were in the FGD wastewater, but additional variation was observed
due to both the presence of other wastes already in the waste
management unit and additional inputs such as bottom ash,
precipitation, and storm water. Accordingly, the EPA determined that
treatment technologies identified for FGD wastewater were generally
applicable to CRL but may in some cases require additional pretreatment
or a combination of technologies. Such additional treatment
technologies could be necessary because of changes to the oxidation
state of some FGD pollutants as they transition to the CCR impoundment.
For example, a chemical precipitation system that would be very
effective at removing particulate arsenic found in FGD wastewater would
be significantly less effective at removing dissolved arsenic or
soluble arsenate that may be present in CRL. Additionally, the EPA
previously recognized that the characterization of wastewater differs
within the layers of a CCR impoundment as it is dewatered and prepared
for closure (88 FR 18835). Therefore, treatment requirements at a unit
that is in the process of closure may also change as closure
progresses.
Despite the complexities discussed above, the EPA conducted its
analyses in the 2024 ELG under the assumption that pollutants in
unmanaged CRL were similar to CRL. Additionally, the EPA assumed that
pollutant removals through chemical precipitation for CRL were similar
to that of flue gas desulfurization wastewater. The EPA then assumed
that pollutant removals through chemical precipitation of unmanaged CRL
were similar to that of managed CRL. While FGD wastewater and waste
management unit wastewaters demonstrate similar types and forms of
pollutants, the same cannot necessarily be said for unmanaged CRL once
it has mixed with groundwater. The EPA is aware that mixing with
groundwater may result in departure from what is otherwise a very well
characterized set of wastestreams, and the EPA received comments
further asserting such.
The 2024 ELG did not rely on any data specific to unmanaged CRL to
conclude that unmanaged CRL mixed with groundwater would fall within
the same ranges of managed CRL evaluated by the EPA. While the EPA
received general comments in the 2024 ELG about the possibility of
interactions of CRL pollutants mixed into groundwater, commenters did
not provide data to demonstrate that CRL mixed into groundwater might
result in pollutant concentrations extending beyond the ranges
evaluated by the EPA for FGDFGD wastewater or CRL. Similarly, in
petitions received after the 2024 ELG and in the 2025 Deadline
Extensions Rule data call, the EPA received no data demonstrating the
pollutant concentrations in unmanaged CRL were untreatable by the
selected BAT technologies. Instead, comments describe ``attenuation,''
such as through adsorption. As the EPA noted in the 2024 rulemaking,
adsorption and other attenuation processes would be expected to remove
pollutants, which means in some cases that chemical precipitation might
not be necessary. In other cases, however, additional stages of
chemical precipitation treatment may be necessary if the groundwater
contains significant concentrations of pollutants from other sources.
E. Control and Treatment Technologies
In general, control and treatment technologies for some
wastestreams have continued to advance. Often, these advancements
provide plants with additional or alternative approaches for complying
with any effluent limitations. In some cases, these advancements have
also decreased the associated costs of compliance. For this proposed
ELG, the EPA incorporated updated information and evaluated several
technologies available to control and treat unmanaged CRL generated by
the steam electric power generating industry. See section VII of this
preamble for details on updated cost information.
[[Page 28496]]
1. Technologies for Treating Unmanaged Combustion Residual Leachate
As described above, in the 2024 ELG the EPA assumed, with little
available data, that unmanaged CRL from landfills and impoundments
includes similar types of pollutants as both flue gas desulfurization
wastewater and managed CRL. As such, the EPA further assumed, with
little available data, that certain treatment technologies identified
for flue gas desulfurization wastewater and managed CRL could also be
used to treat unmanaged CRL. The following describes these potential
types of treatment and handling practices for unmanaged CRL:
Chemical precipitation. Chemicals are added as part of the
treatment system to help remove suspended solids and dissolved solids,
particularly metals. The precipitated solids are then removed from the
solution by coagulation/flocculation followed by clarification and/or
filtration. The 2024 ELG focused on a specific design that employs
hydroxide precipitation, sulfide precipitation (organosulfide), and
iron coprecipitation to remove suspended solids and convert soluble
metal ions to insoluble metal hydroxides or sulfides. Chemical
precipitation was part of the BAT technology basis for the effluent
limitations in the 2024 ELG. While the EPA's historical record shows
that chemical precipitation can be a robust process that can treat most
pollutants found in the various coal combustion wastestreams and may be
effective at treating heavy metals, the limited data available to the
EPA shows that leachate from impoundments that mixes with groundwater
must be evaluated as a process differently than managed CRL. Chemical
precipitation can be readily tailored (such as by adjusting the pH and
the dose of the reagents used to convert dissolved substances into
solid particles) to meet the variability encountered in CRL wastewater
(DCN SE12168).
High-hydraulic-residence-time biological reduction. The
EPA identified three types of biological treatment systems used to
treat flue gas desulfurization wastewater: anoxic/anaerobic fixed-film
bioreactors (which target removals of nitrogen compounds and selenium),
anoxic/anaerobic suspended growth systems (which target removals of
selenium and other metals), and aerobic/anaerobic sequencing batch
reactors (which target removals of organics and nutrients).
Low-hydraulic-residence-time biological reduction. This
biological treatment system targets removal of selenium and nitrate/
nitrite using fixed-film bioreactors in smaller, more compact reaction
vessels. The bacteria reduce soluble selenate and selenite to insoluble
selenium, which is a filterable solid; nitrate is converted into
nitrogen gas. This system differs from the high-hydraulic-residence-
time biological treatment system evaluated in the 2015 ELG, in that the
low-hydraulic-residence-time system is designed to operate with a
shorter residence time (approximately one to four hours, compared to a
residence time of 10 to 16 hours for high-hydraulic-residence-time)
while still achieving significant removal of selenium and nitrate/
nitrite. Both systems are sensitive to high total dissolved solids
levels, so proper operation is necessary to accommodate fluctuations in
the wastewater.
Zero-Discharge Technologies
[cir] Membrane filtration. A membrane filtration system (e.g.,
microfiltration, ultrafiltration, nanofiltration, forward osmosis,
electrodialysis reversal, or reverse osmosis (RO)) is designed
specifically for high-TDS and high-TSS wastestreams. These systems are
designed to minimize fouling and scaling associated with industrial
wastewater. These systems typically use pretreatment for potential
scaling agents (e.g., calcium, magnesium, sulfates) combined with one
or more types of membrane technology to remove a broad array of
particulate and dissolved pollutants from flue gas desulfurization
wastewater. The membrane filtration units may also employ advanced
techniques, such as vibration or creation of vortexes to mitigate
fouling or scaling of the membrane surfaces. Membrane filtration can
achieve zero discharge by recirculating permeate from a reverse osmosis
system back into plant operations.
[cir] Spray evaporation. Spray evaporation technologies, which
include spray dry evaporators (SDEs) and other similar proprietary
variations, evaporate water by spraying fine misted wastewater into hot
gases. The hot gases allow the water to evaporate before contacting the
walls of an evaporation vessel, treating wastewater across a range of
water quality characteristics such as TDS, TSS, or scale forming
potential. Spray evaporation technologies use a less complex treatment
configuration than brine concentrator and crystallizer systems (see the
description of thermal evaporation systems) to evaporate water using a
heat source, such as a slipstream of hot flue gas or an external
natural gas burner. Spray evaporation technologies can be used in
combination with other volume reduction technologies, such as
membranes, to maximize the efficiency of each process. Concentrate from
a reverse osmosis system can then be processed through the spray
evaporation technology to achieve zero discharge by recirculating
permeate from the reverse osmosis system back into plant operations.
[cir] Thermal evaporation. Thermal evaporation systems use a
falling-film evaporator (or brine concentrator), following a softening
pretreatment step, to produce a concentrated wastewater stream and a
distillate stream to reduce wastewater volume by 80 to 90 percent and
reduce the discharge of pollutants. The concentrated wastewater is
usually further processed in a crystallizer that produces a solid
residue for landfill disposal and additional distillate that can be
reused within the plant or discharged. These systems are designed to
remove a broad spectrum of pollutants to very low effluent
concentrations.
Additionally, the EPA identified the following potential types of
in situ treatment and handling practices for unmanaged CRL in the
subsurface that would not be applicable to flue gas desulfurization
wastewater or managed CRL. These in situ technologies require careful
characterization of site-specific subsurface conditions that may vary
widely in terms of biogeochemistry, pollutants present, and facility
configurations.
Impermeable Barriers. Impermeable barriers are underground
walls that are designed to prevent or control the flow of groundwater
to a certain location. An impermeable barrier placed in the subsurface
would prevent the spread of pollutants from discharging to a WOTUS.
Permeable Reactive Barriers. Permeable reactive barriers
(PRB) are permeable barriers containing solid reagents or other
reactive materials that are placed into the subsurface. As unmanaged
CRL or contaminated groundwaters flow through permeable barriers,
pollutants react with the reagents and are subsequently removed or
treated.
Injection. Injection technologies involve injection of
liquid reagents or reactive adsorbents into the subsurface. The liquid
reagents or adsorbents then react with and subsequently remove
pollutants that may be present in unmanaged CRL or contaminated
groundwaters. Injection approaches often require careful
characterization of site-specific biogeochemical conditions to ensure
effective delivery of reagents.
Additional discussion regarding updates to sources of data and new
data
[[Page 28497]]
obtained by the EPA may be found in the record (DCN: SE1210505).
VI. Proposed Rule
This proposal evaluates three regulatory options and identifies one
preferred option (Option 1), as shown in Table VI-1 of this preamble.
The three regulatory options address unmanaged combustion residual
leachate in different ways and using different technologies and
management practices as the basis for doing so. In addition to some
specific requests for comment included throughout this proposal, the
EPA solicits comment on all aspects of this proposal, including the
information, data, and assumptions the EPA relied upon to develop the
three regulatory options, as well as the proposed BAT, effluent
limitations, and alternate approaches included in this proposal.
Table VI-1--Proposed Rule BAT Options for Unmanaged CRL Subcategory
----------------------------------------------------------------------------------------------------------------
For discharges of unmanaged CRL to a
WOTUS that: Option 1 (Preferred) Option 2 (2024 ELG) Option 3
----------------------------------------------------------------------------------------------------------------
Leached from a landfill or Numerical limits on Numerical limits on Zero-discharge limits.
impoundment into the subsurface and mercury and arsenic. mercury and arsenic.
mixed with groundwater before being
captured and pumped to the surface
for discharge directly.
Are the functional equivalent of a BAT limits developed on Numerical limits on Zero-discharge limits.
direct discharge as determined by a BPJ basis by the mercury and arsenic.
the permitting authority. permitting authority.
----------------------------------------------------------------------------------------------------------------
This proposal does not seek to define what constitutes the
``functional equivalent'' of a direct discharge. Moreover, the EPA is
not determining that all potential discharges through groundwater from
landfills and surface impoundments are the functional equivalent of a
direct discharge to a WOTUS. Rather, the EPA is proposing limitations
that would apply to any discharge that is the functional equivalent of
a direct discharge through groundwater to a WOTUS and, thus, requires
an NPDES permit. The threshold standard for the ``functional
equivalence'' determination is outside the scope of this rule. In this
proposed rule, the EPA reaffirms its longstanding position, which is
consistent with the County of Maui decision: the determination of what
constitutes the functional equivalent of a direct discharge is case-
specific, and some landfills and surface impoundments may meet the
definition of point sources under the CWA.
Thus, to the extent that discharges from landfills, surface
impoundments, or other features could be considered the functional
equivalent of a direct discharge of unmanaged CRL to a WOTUS, this
proposal would inform the permitting authority of the appropriate
technology-based effluent limitations that would apply. Determining
whether a functional equivalent of direct discharge exists at any
particular impoundment or landfill is a task for permitting authorities
and outside the scope of this proposed rulemaking.
In all three regulatory options, the EPA proposes to codify
additional definitions to clarify applicability of the unmanaged CRL
limitations.
First, for purposes of this subpart, the EPA proposes to
define a ``closed coal combustion residuals waste management unit'' at
40 CFR 423.11(gg) to provide clarity as to which impoundments and
landfills meet the criteria of being closed.
The EPA proposes to further clarify the applicability of
the effluent limitations with new provisions at 40 CFR 423.13(l)(3).
[cir] The first provision states that the effluent limitations in
this subcategory do not apply to retired power plants, and that case-
by-case BAT limitations based on the permitting authority's best
professional judgment (BPJ) continue to apply.
[cir] The second provision proposes that unmanaged CRL limitations
do not apply to landfills closed by the 2024 ELG's effective date of
July 8, 2024, and that case-by-case BAT limitations based on BPJ
continue to apply. The EPA solicits comment on these additional
provisions.
The EPA proposes a correction to the CFR text at section
423.13(l)(1)(i) where ``(1)(2)'' was mistakenly printed instead of
``(l)(2).''
The EPA proposes to clarify in section 423.13(l)(2)(ii)(B)
that BAT limitations based on BPJ apply to unmanaged CRL generated
before the effective date of the ELG.
A. Description of the Options
The following regulatory options apply to the two types of
unmanaged leachate as defined in the 2024 ELG:
Discharges of pumped unmanaged CRL: CRL that has leached from a
landfill or impoundment into the subsurface and mixed with groundwater,
after which it has been captured and pumped to the surface for
discharge directly to a WOTUS.
Functional equivalent of a direct discharge of unmanaged CRL: CRL
that has been determined, by the permitting authority, to be the
functional equivalent of a direct discharge to a WOTUS through
groundwater.
1. Option 1
Functional Equivalent of a Direct Discharge of Unmanaged CRL
Option 1 would rely on discretion of the permitting authority to
set case-by-case BAT limitations that apply to functional equivalents
of a direct discharge of unmanaged CRL, after evaluating site-specific
factors relevant to the treatment to of unmanaged CRL.
This option would provide the greatest flexibility to ensure
appropriate technology-based requirements are set while giving
appropriate consideration to all site-specific factors impacting a
utility's ability to collect and treat unmanaged CRL. This flexibility
is appropriate given the fact that permitting authorities (which are
typically states) are better situated on a case-by-case basis at the
time of permit issuance to assess the difficulty in capturing and
treating unmanaged CRL. Similarly, due to the unprecedented, rapidly
increasing energy demands throughout the U.S. (as discussed in both the
2025 Deadline Extensions Rule, and section V.A of this preamble),
including the extended operations of EGUs due to ``must run orders''
and the overall need to ensure grid reliability, as well as the
resulting likelihood that the 2024 ELG overestimated the number of
existing coal-fired power plants that would retire, this flexibility
would appropriately allow the permitting authority to select the
technologically available and economically achievable treatment method
based on plant-specific technological, economic, and other relevant
factors.
Over the past decade, whenever the EPA has revised the steam
electric ELGs, the Agency has carefully considered the impacts of new
requirements on the overall outlook of the industry, including impacts
on electricity generation. This proposal continues in that tradition,
but is more
[[Page 28498]]
tailored to the dynamic energy market of today, by providing permitting
authorities with the flexibility to make regulatory decisions that
reflect the on-the-ground factors that a specific facility may be
contending with at the time of issuance or re-issuance of an NPDES
permit, and to ensure that proper consideration is given to the unique
needs of specific utilities in order to ensure the continued delivery
of affordable and reliable power to U.S. families and businesses. While
not meant to be a complete list of considerations, the permitting
authority should consider the following when evaluating potential model
technologies on a BPJ basis:
site hydrology;
hydraulic conductivity;
groundwater plume length and age;
background contaminants present in groundwater;
chemical form and concentration of pollutants in mixed CRL
and groundwater;
relative flows and volumes of contributing groundwater;
biogeochemical properties of soils;
changes in local energy demand;
changes in energy costs to consumers;
non-water quality environmental impacts, such as solid
waste generation or air pollution from waste management;
changes in fuel consumption due to waste management; and
pending must-run orders or similar demands that a utility
stay in operation longer than planned.
Discharges of Pumped Unmanaged CRL
Option 1 proposes to maintain the existing 2024 ELG mercury and
arsenic limitations applicable to discharges of pumped unmanaged CRL.
The technology basis for BAT is chemical precipitation, employing
hydroxide precipitation, sulfide precipitation (organosulfide), and
iron coprecipitation. For further information on this BAT model
technology and derivation of these numeric limitations, see the 2024
Steam Electric ELG Technical Development Document (TDD) (DCN SE11757).
Where discharges of pumped unmanaged CRL are occurring, as of the
effective date of this ELG, the EPA proposes the limitations must be
met as soon as possible, but no-later-than December 31, 2034. This no-
later-than date, which is consistent with the latest compliance date
for zero-discharge requirements promulgated in the 2025 Deadline
Extensions Rule, is being proposed because it would provide permittees
with appropriate time to make comprehensive waste management decisions
when evaluating how to most efficiently meet the suite of requirements
on coal-fired power plants from effluent guidelines. Discharges of
pumped unmanaged CRL that commence after the effective date of this ELG
must meet these numeric limitations as soon as possible, but no later
than the date unmanaged leachate pumping commences or December 31,
2034, whichever is later.
2. Option 2
Functional Equivalent of a Direct Discharge of Unmanaged CRL
Option 2 proposes to maintain the existing 2024 ELG mercury and
arsenic limitations for functional equivalents of a direct discharge of
unmanaged CRL. The technology basis for BAT is chemical precipitation,
employing hydroxide precipitation, sulfide precipitation
(organosulfide), and iron coprecipitation. For further information on
this BAT model technology and derivation of these numeric limitations,
see the 2024 Steam Electric ELG TDD (DCN SE11757).
Where such discharges are occurring, as of the effective date of
the ELG, the EPA proposes to retain the requirement that these
limitations must be met as soon as possible, but no later than December
31, 2029.
Discharges of Pumped Unmanaged CRL
Option 2 proposes to also maintain the existing 2024 ELG mercury
and arsenic limitations for discharges of pumped unmanaged CRL. The
technology basis for BAT is chemical precipitation, employing hydroxide
precipitation, sulfide precipitation (organosulfide), and iron
coprecipitation. For further information on this BAT model technology
and derivation of these numeric limitations, see the 2024 Steam
Electric ELG TDD (DCN SE11757).
Where such discharges are occurring, as of the effective date of
the ELG, the EPA proposes to retain the requirement that these
limitations must be met be met as soon as possible, but no later than
December 31, 2029.
3. Option 3
Functional Equivalent of a Direct Discharge of Unmanaged CRL
Option 3 proposes to establish a zero-discharge requirement on
pollutants from functional equivalents of a direct discharge of
unmanaged CRL and would establish BAT limitations for mercury and
arsenic based on chemical precipitation treatment as an interim step.
The BAT basis for functional equivalents of a direct discharge of
unmanaged CRL is the implementation of spray dry evaporators, the same
as the 2024 ELG specified for (managed) CRL. See the 2024 ELG Preamble
for additional detail on this approach.
Where functional equivalents of a direct discharge of unmanaged CRL
that have been identified by a permitting authority are occurring as of
the effective date of the ELG, the EPA proposes the zero-discharge
limitation must be met as soon as possible, but no later than December
31, 2034. For functional equivalents of a direct discharge of unmanaged
CRL commencing after the effective date of the ELG, the limitations
must be met as soon as possible, but no later than the date unmanaged
leachate pumping commences or December 31, 2034, whichever is later.
The 2034 date reflects the deadlines established in the 2025 Deadline
Extensions Rule and provides flexibility for those plants seeking to
combine wastewater flows for more effective and efficient treatment.
Discharges of Pumped Unmanaged CRL
Under this option, the EPA proposes to establish a zero-discharge
limitation for all pollutants in pumped unmanaged CRL with interim BAT
limitations on mercury and arsenic based on chemical precipitation
treatment. The BAT basis for discharges of pumped unmanaged CRL is the
implementation of spray dry evaporators, the same as the 2024 ELG
specified for managed CRL. See the 2024 ELG Preamble for additional
detail on this approach.
Where discharges of pumped unmanaged CRL are occurring as of the
effective date of the ELG, the EPA proposes the zero-discharge
limitations must be met as soon as possible, but no later than December
31, 2034. For discharges of pumped unmanaged CRL commencing after the
effective date of the ELG, the limitations must also be met as soon as
possible, but no later than the date unmanaged leachate pumping
commences or December 31, 2034, whichever is later. The 2034 date
reflects the deadlines established in the 2025 Deadline Extensions Rule
and furthermore provides flexibility for those plants seeking to
combine wastewater flows for more effective and efficient treatment.
B. Rationale for the Proposed Rule
1. Rationale for Not Proposing Option 3 as BAT
Unacceptably High Compliance Costs for Unmanaged CRL
The EPA is not proposing to select Option 3 as the preferred option
for
[[Page 28499]]
BAT for both types of discharges of unmanaged CRL because total costs
of the option to the industry as a whole are unacceptably high and not
economically achievable. As discussed in the Technical Support memo
(DCN SE12105), the EPA has revised its cost estimates for this
proposal, and the revised cost estimates for spray dry evaporators to
achieve zero discharge for both categories of unmanaged CRL are $1.1
billion per year in the lower bound and $2.2 billion in the upper bound
(see Table VII-1 and the Technical Support memo (DCN SE12105)).
The costs associated with this option are nearly an order of
magnitude higher than total costs of the 2024 ELG to the industry for
controlling all of the remaining end-of-pipe discharges from every
other wastestream combined. In 2024, the EPA estimated that the total
annualized costs to the industry of zero discharge could be as high as
$3.69 billion. At that time, EPA determined these costs were
unreasonable. With the revised economic analysis in this proposed rule,
the EPA has determined that the annualized cost for the zero-discharge
option in the 2024 ELG was likely an overestimation of costs; however,
despite more representative cost calculations supporting this proposal,
the EPA still proposes that the costs to achieve zero discharge ($1.1
to $2.2 billion) are unreasonable. Costs are one of the statutory
factors that the EPA must consider, and courts have found that the EPA
may properly rely on costs in rejecting potential BAT technologies. See
e.g., BP Expl. & Oil Inc. v. EPA, 66 F.3d 784, 799-800 (6th Cir. 1995).
For further discussion of costs and economic achievability, see the
Technical Support memo (DCN SE12105).
Additional Cost Burdens Reflecting the Duration of Discharges for
Unmanaged CRL
In addition to the unacceptably high costs of Option 3, the EPA has
identified several other areas where the cost analysis was unable to
account for potentially significant expenditures by a permittee, which
would further exacerbate the economic impacts of this option. Most
notably, the duration of the discharges in question and the need for
treatment beyond the operating life of a regulated utility may
significantly increase cost burdens for this option. The EPA is
concerned that the 2024 ELG did not fully account for the lack of
revenue generated by closed utilities, and thus the lack of funding
available, to implement treatment in an economically achievable way.
Typically, ELGs no longer apply after an entity ceases the industrial
operation generating pollutant discharges; however, given the nature of
unmanaged CRL, and the influence contaminated groundwater has on the
volume and duration of this wastestream, unmanaged CRL discharges that
require treatment could incur costs associated with wastewater
treatment operations long after the associated utility has retired and
ceased generating electricity and revenue. Economic achievability
assessments to support ELGs typically evaluate the compliance costs
with respect to revenue and closures of facilities due to compliance
costs, which would lend itself to further determine these costs are
economically unachievable for any facility that has already closed and
has no revenue to support these compliance costs. The increased cost of
meeting zero-discharge limitations in unmanaged CRL may be unacceptable
in light of the unique position of retired facilities with no revenue
with which to support costs associated with such limitations.
Furthermore, the EPA acknowledges that the 2024 ELG record
describes a spray dry evaporator employed to achieve zero-discharge of
legacy wastewater at the Boswell Energy Center in Cohasset, Minnesota
(DCN SE11621A1). The 2024 ELG concluded that the spray dry evaporator
was not technologically available for this subcategory. In particular,
many facilities will dewater and close their ash impoundments after the
facility ceases generating electricity or combustion of coal. Without
electricity production, there is no slipstream of flue gas with which
to operate the same type of evaporator system that is achieving zero
discharge at Boswell. No new information is available that rebuts this
conclusion. For this reason, the EPA proposes that for facilities that
do not have the same plant-wide configuration as Boswell, zero-
discharge of unmanaged CRL may not be technologically available. In
other instances, the facility may be unable to operate zero-discharge
technologies during a planned or unplanned outage (DCN SE 1210303). The
EPA has been unable to identify a basis for further subcategorization
that would address the many differences between individual plants.
Feasibility of a Zero-Discharge Standard for Unmanaged CRL
As another potential basis supporting the EPA's proposal to reject
Option 3 as BAT, the EPA has looked carefully at the feasibility of a
zero-discharge standard in light of the unique nature of unmanaged CRL
discharges and the influence contaminated groundwater has on the
volumes and durations of these wastestreams, which may pose unique
challenges for demonstrating the capabilities of zero-discharge
technology.
In the 2024 ELG analysis, the EPA made the assumption that the
pollutants in unmanaged CRL were similar to (managed) CRL, and by
extension also similar to FGD wastewater. Accordingly, the EPA assumed
zero-discharge technologies identified for CRL and FGD could reasonably
be applied to unmanaged CRL. The EPA is aware of at least one plant
that as employed a zero-discharge technology for all wastestreams at
the plant, including unmanaged CRL.
In the 2024 ELG, the EPA did not have performance data
demonstrating that the volume of unmanaged CRL as estimated for costing
purposes to be pumped from groundwater would result in zero-discharge
of all pollutants from unmanaged CRL that is a functional equivalent of
a direct discharge (as identified by a permitting authority). As the
EPA did not receive or identify performance data to the contrary, the
EPA, despite the lack of data, found in the 2024 ELG that discharges of
pumped unmanaged CRL could meet a zero-discharge standard by the
application of a pump-and-capture treatment system that includes spray
dry evaporators (although this option was rejected due to its high
costs). In this proposal, the EPA's updated analysis indicates that a
zero-discharge limit is still not economically achievable, and it may
not be technologically available as applied to all discharges of
unmanaged CRL that are the functional equivalent of direct discharges.
The volume and pollutant concentration of these functional equivalent
discharges are highly dependent on prior groundwater contamination from
surface impoundments or landfills and the depth to the existing
groundwater table. Operational conditions, such as the number of times
the wastestream needs to be cycled or the accumulation of brine, may
vary as a result of fluctuations in the volume required to be treated
and changes in pollutant concentrations. Groundwater flows may be
variable (such as seasonable aquifer replenishment or due to saltwater
intrusion) and the pollutant concentrations may fluctuate such that a
volume reduction step or additional storage capacity is needed. The
impoundment or landfill may be several miles away from the power plant,
requiring additional staff and resources
[[Page 28500]]
to implement control strategies. On the other hand, under certain
conditions, as the EPA acknowledged in the 2024 Rule, absorption and
attenuation of pollutants in unmanaged CRL could make treatment easier
and, in that case, would likely decrease costs of such treatment. (DCN
SE12165). The EPA's cost analysis appropriately reflects the typical
range of costs of compliance for the industry nationwide. Nevertheless,
these other factors identified above may increase the costs at some
sites that markedly depart from the range of costs already considered
in the EPA's analysis. As some petitioners have pointed out, completely
intercepting and capturing any and all leaks of unmanaged CRL is
challenging, if not impossible, for at least some power plants. Even if
it were possible to intercept all contaminated groundwater, the energy
for evaporation might not be available or could be cost prohibitive.
In summary, it is likely that a subset of utilities subject to a
potential zero-discharge requirement would not be able to comply with
the requirements, even if they were able to capture and treat the vast
majority of a plume before it reaches surface water simply as a
function of existing groundwater (previously contaminated with
pollutants that resulted from the operation of a generating unit)
subsequently reaching a WOTUS in a fashion that a permitting authority
determines is still a functional equivalent of a direct discharge of
unmanaged CRL. As such, the EPA proposes that setting a broad zero-
discharge standard for unmanaged CRL is not only economically
unachievable but also has not been demonstrated to be technically
feasible for the industry as a whole due to the unique make-up of each
unmanaged CRL discharge.
Other Zero-Discharge Technologies for Treating Unmanaged CRL
For the 2024 ELG and for this proposal, the EPA evaluated other
zero-discharge technologies that could also eliminate the discharge of
unmanaged CRL wastewater such as thermal systems. However, the EPA is
not proposing to rely upon them as a basis for BAT limitations because
they achieve the same pollutant reductions as the proposed Option 3 BAT
technology basis (spray dry evaporators) but typically at a higher
cost. The EPA has already rejected Option 3 on the basis of high costs.
Nevertheless, the EPA solicits comment on the technologies that could
constitute an alternative BAT technology basis for unmanaged CRL.
2. Rationale for Not Proposing Option 2 as BAT
Unacceptably High Compliance Costs for Unmanaged CRL
The EPA is not proposing Option 2 as the preferred option for BAT
for both types of discharges of unmanaged CRL because total costs to
the industry as a whole are unacceptably high and the EPA proposes that
these costs are not economically achievable. As the EPA did not receive
or identify performance data to the contrary, the EPA assumes that,
despite the lack of data, discharges of pumped unmanaged CRL could meet
the numeric limitations for mercury and arsenic. However, as discussed
in the Technical Support memo (DCN SE12105), the EPA has revised its
costs estimate for this proposal based upon a corrected and updated
baseline as compared to the one utilized in the 2024 ELG, and the
revised total annualized cost estimates for Option 2 is $660 million
per year in the lower bound and $1.4 billion per year in the upper
bound at 3.76 percent average cost of capital (see Table VII-1 and the
Technical Support memo (DCN SE12105)).
These costs are nearly an order of magnitude higher than total
costs to the industry to control all of the remaining end-of-pipe
discharges from every other wastestream covered by the 2024 Rule
combined. The EPA proposes that expecting the industry as a whole to
bear these costs is unreasonable. Costs are one of the statutory
factors that the EPA must consider, and courts have found that the EPA
can properly rely on costs in rejecting potential BAT technologies. See
e.g., BP Expl. & Oil Inc., 66 F.3d at 799-800. For further discussion
of costs and economic achievability, see section VII.C of this
preamble. Overall, the EPA proposes that the increased costs of
imposing stringent national effluent limitations under Option 22
(relative to site-specific costs in Option 1) is unacceptable,
particularly in light of the unique position of retired facilities with
no revenue with which to support costs associated with meeting the
effluent limitations that would apply (see section V.C of this
preamble).
For the reasons discussed above, the EPA is not proposing Option 2
as the preferred option for BAT because total costs to the industry as
a whole are unacceptably high and the EPA proposes that these costs are
not economically achievable. In addition, the EPA has identified other
sources of uncertainty that could lead to increased costs beyond those
included in the revised cost analysis in certain cases, which are
discussed below. These potential additional costs add further support
for the EPA's proposed finding that Option 2 presents unacceptably high
total costs. The Agency solicits comments on the extent to which these
additional considerations should factor into the EPA's final rule.
The Presence of Different Forms and Concentrations of Pollutants at
Each Site Could Exacerbate Cost Impacts
The EPA emphasizes that there is a general lack of detailed
characterization data for unmanaged CRL, particularly where leachate
has mixed with groundwater. As discussed in section V, while there is
an abundance of data characterizing the sources of waste and the
wastewater itself in impoundments and landfills, data available on
leachate is usually modeled, calculated, or estimated, and the
characteristics of leachate likely change the moment it mixes with
groundwater or undergoes some other physical or chemical change.
Without accurate characterization in hand, it is difficult for the EPA
to account for uncertainties in additional costs that may be required
to meet broadly applicable technology-based limitations in all cases.
Impoundments and landfills reflect anywhere from years to decades
of use, with non-homogenous layers reflecting different coal types,
precipitation and stormwater, and in some cases bottom ash. When water
seeps through the impoundment and mixes with groundwater, there are
changes in the ensuing wastewater, including but not limited to pH,
temperature, flow rate, and alkalinity. These parameters can influence
the chemical forms of the pollutants that are present (DCN: SE12166).
The EPA notes that in the 2015 ELG rule analysis, the Agency
assumed that the pollutants in FGD and (managed) CRL were similar. In
addition to FGD wastewater, an impoundment or landfill may also receive
FGD leftover materials or residues, fly ash, bottom ash, boiler slag,
scrubber residues, and cenospheres.\5\ Data available to date show this
assumption still holds.
---------------------------------------------------------------------------
\5\ Cenospheres are small, lightweight, ceramic spheres
comprised of silica and alumina that result from burning of coal at
high temperatures. They are recovered and used for fillers in
materials like concrete, polymers, and paints.
---------------------------------------------------------------------------
In contrast to (managed) CRL, the EPA finds unmanaged CRL that has
mixed with groundwater shows a much higher variability. For example,
the pH of coal ash CRL from all coal types ranges from 4.16 to 12.2,
with a median of 9.11 (DCN SE11725). Groundwater is usually slightly
alkaline and is buffered in the presence of limestone or carbonate.
[[Page 28501]]
Groundwater can become acidic if it passes through coal, sulfides,
organics, or is otherwise affected by certain forms of pollution (DCN
SE12120). The EPA has also evaluated facility-specific data showing
that pollutants in groundwater laden with CRL, particularly their forms
and concentrations, are not always similar to FGD and traditionally
managed CRL (DCN SE12167). This is due to both the reaction of the
pollutants in CRL with groundwater, and the presence of pollutants in
the groundwater itself that may not otherwise be present in the CRL.
There is also the possibility, as discussed earlier, of adsorption and
attenuation that would change the characterization of unmanaged CRL
(DCN SE12165). Although the 2024 Rule acknowledged this possibility and
concluded that ``to the extent adsorption and other attenuation
processes would remove pollutants, this would only make it easier'' to
achieve the chemical precipitation-based limitations, 89 FR 40251, this
does not represent a complete picture of the differences that are
expected to exist in unmanaged CRL that has mixed with groundwater and
associated difficulties with meeting such limitations. While CRL is
typically alkaline, at least three plants have shown arsenate in the
unmanaged CRL wastewater (see section V of this preamble). As another
example, selenate (selenium VI) favors oxygen-rich, alkaline
environments. Analysis of 2025 monitoring data shows untreated CRL has
a median pH near neutrality, but it can go as high as pH 9 (DCN
SE12135). Should the aquifer be strongly alkaline or weakly buffered,
selenate formation cannot be ruled out. To remove selenate in this
situation usually requires additional technologies beyond chemical
precipitation--which would represent additional costs to a facility--
such as biological treatment, membrane filtration (such as reverse
osmosis), or ion exchange.
Biological treatment is temperature dependent, pH sensitive, and
requires sufficient alkalinity to buffer the system. Biological
treatment must also be followed by a disinfection process. If the EPA
were to establish chemical precipitation plus membrane filtration as
the preferred option, it would cost at least 1.7 times as much as
chemical precipitation alone,\6\ but in most cases would not remove
further pollutants beyond chemical precipitation alone. The 2024 ELG
cost methodology shows membrane filtration and ion exchange are more
costly than chemical precipitation (DCN SE11724).
---------------------------------------------------------------------------
\6\ At an average flow rate of 100 gpm, annualized costs (7
percent discount rate over 20 years) of chemical precipitation +
membrane filtration costs 1.7 times as much as chemical
precipitation alone.
---------------------------------------------------------------------------
Because of the highly unique nature of each unmanaged CRL
wastestream and the unsuitability of chemical precipitation to treat
all pollutants potentially present in unmanaged CRL that has mixed with
groundwater without adding costs beyond what the EPA has already
determined to be too costly, the EPA proposes to reject Option 2 in
favor of Option 1, which would authorize the permitting authority to
establish BAT limitations based on a BPJ determination that is better
suited to handle site-specific factors. The EPA solicits data on the
characterization of leachate mixed with groundwater and treatment
technology performance, including both concentrations and chemical
forms of any pollutants.
The Need To Collect a Larger Volume of Groundwater Than Estimated To
Meet the Limitations Would Exacerbate Cost Impacts and May Not be
Feasible
Another fact that supports the EPA's proposal not to prefer Option
2 is that the volume and pollutant concentrations in the functional
equivalent direct discharge are highly dependent on prior groundwater
contamination from surface impoundments or landfills and the depth to
the existing groundwater table. The 2024 ELG analysis assumed that,
once an appropriate volume of groundwater laden with unmanaged CRL was
removed from the aquifer, it could be treated to meet the numeric
limitations for arsenic and mercury. The 2024 ELG analysis
conservatively assumed the groundwater and the unmanaged CRL both had
the pollutants found in CRL; i.e., the total volume collected was
subject to treatment as if the total volume was CRL. The analysis did
not consider whether any remaining pollutants not collected would meet
the numeric limitations when the remaining groundwater ``daylights'' or
otherwise meets with surface waters. In other words, at issue here is
not whether some of the unmanaged CRL mixed with groundwater can
feasibly be collected and treated, rather it is an issue of how much
unmanaged CRL mixed with groundwater must be collected before there is
assurance that the ELG requirements have been met. Even if most of the
unmanaged CRL coming from the landfill or impoundment is captured and
treated, there could be ongoing exceedances at the functional
equivalent direct discharge point. Therefore, in this case, a subset of
power plants subject to numeric limitations for mercury and arsenic
would not be able to comply with the requirements, even if they were
able to capture and treat the vast majority of a plume before it
reached surface water, assuming the permitting authority determines the
plant still has the functional equivalent of a direct discharge.
Neither the 2024 ELG analysis nor this proposal has data identifying
how often these situations would occur. When such situations do occur,
however, the volume of groundwater with unmanaged CRL collected is
potentially underestimated. This could add significant costs for some
plants where the EPA is already proposing the total costs to the
industry as a whole are too high. As such, the EPA proposes that
broadly setting numeric limitations for unmanaged CRL is not only
economically unachievable but also has not been adequately demonstrated
to be technically feasible due to the unique make-up of each stream of
unmanaged CRL.
Additional Costs Incurred as a Result of Multiple Management Units or
Aquifers Would Further Exacerbate Cost Impacts
In 2009, the RCRA CCR rule survey identified 676 impoundments and
landfills across 240 facilities (DCN SE12167). At 95 of those
facilities, there is only one impoundment or landfill identified; 581
facilities have more than one management unit. In some instances,
multiple impoundments are located adjacent to each other or in an
adjoining manner. As discussed in section V, the EPA is further aware
of 111 power plants that have management units that are unlined, not-
clean closed, or are undergoing corrective action. This reflects the
upper bound number of plants that may be determined to have the
functional equivalent of a direct discharge. Consistent with the RCRA
CCR rule, the analysis supporting this proposal considers the costs for
wells, collection, capture, and treatment with chemical precipitation
based on the groundwaters' flow and direction, thus intending to
capture the primary plume of groundwater laden with CRL (DCN SE12169).
The EPA is already aware that, in some cases, the waste management unit
(especially landfills) may be located some distance away from the
electric generating unit. (DCN: SE12104). However, there are likely
instances where more than one impoundment would need to be
independently managed and controlled to meet the numeric limitations
under Option 2; in this case, the estimated costs are likely
understated. There may also be instances where the groundwater exhibits
changes in direction and flow
[[Page 28502]]
to the extent a single system of wells is unable to capture the
groundwater laden with CRL; in this case, the costs are also likely
understated. In both instances, the applicability of Option 2's numeric
limitations is a result of the site-specific determination of
functional equivalent of a direct discharge, a decision which is beyond
the scope of this proposal. The total costs of Option 2, however, are
already high enough that any additional costs would further exacerbate
the proposed lack of economic achievability of that option. While the
possibility of the costs for collecting, pumping, and treating
groundwater could have been underestimated for the 2024 ELG, it was not
a concern there because the total costs were not near the range where
economic achievability was thought to be an issue.
The EPA is also aware that some facilities may have impoundments or
landfills located near more than one aquifer (DCN SE12103). Again, the
EPA is not determining here that each impoundment or landfill is
located such that where there is a functional equivalent of a direct
discharge. However, multiple treatment systems may need to be deployed
to meet the proposed limitations, whereas the EPA's cost methodology
only presents costs for one treatment system. In light of the revised
costs presented in this proposal, the added costs of additional systems
could exacerbate the EPA's proposed findings regarding lack of
affordability and provide further reason not to prefer Option 2.
The Duration of Discharges of Unmanaged CRL May Increase Cost Burdens
Finally, as with Option 3, the duration of the discharges in
question and the need for treatment beyond the operating life of a
regulated utility may significantly increase the economic impacts of
this option. This may provide additional support in favor of rejecting
Option 2.
4. Rationale for Proposing Option 1 as the Preferred Option for BAT
After considering updates to the industry-wide economic analyses,
and further analysis of the feasibility of broadly setting numeric
limitations on discharges of unmanaged CRL, the EPA is proposing to
establish through regulation that, for functionally equivalent direct
discharges of unmanaged CRL, BAT limitations must be derived by the
permitting authority on a case-by-case BPJ basis. Additionally, the EPA
is also proposing to retain the numeric discharge limitations for
mercury and arsenic based on chemical precipitation for discharges of
pumped unmanaged CRL.
Functional Equivalent of a Direct Discharge of Unmanaged CRL
Effluent limitations derived by permitting authorities via BPJ
must, by design, be technologically available and economically
achievable for a particular facility, after consideration of all
appropriate factors (see section IV.B.3 for additional details). In
addition, BPJ limitations have the flexibility necessary to consider
highly site-specific factors to each individual plant, such as volumes
of surrounding aquifers, feasibility of pumping and capturing
groundwater, different hydrogeological conditions of the site, and
volumes and locations of discharges of unmanaged CRL, all of which are
issues that the EPA identified in connection with rejecting Options 2
and 3.
The EPA's proposed preferred option, Option 1, also complies with
the CWA section 301 mandate that BAT limitations result in ``reasonable
further progress'' toward the Act's goal of eliminating the discharge
of all pollutants because it represents a step beyond the BPT-level of
control, which is based on surface impoundments alone. 33 U.S.C.
1311(b)(2)(A). Under Option 1, for functionally equivalent direct
discharges of unmanaged CRL, permitting authorities must consider more
stringent limitations beyond those based on surface impoundments,
including whether such limitations are available and achievable for the
particular facility, as determined in accordance with the section 304
consideration factors. Some of the technology options for BAT that the
permitting authority might consider are discussed in section V.E of
this preamble, and the EPA's record includes potential limitations that
could be attained based on these technologies.
The EPA also notes that the BPJ approach provides appropriate
flexibility, given the rapidly increasing energy demands across the
U.S. and the newfound pressures put upon these utilities to produce
inexpensive and reliable electricity (as discussed in both the Steam
Electric 2025 Deadline Extensions Rule and in section V of this
preamble), including uncertainty surrounding retirements of existing
coal-fired power plants, extended operations of EGUs due to ``must run
orders,'' and the overall need to ensure grid reliability.
Discharges of Pumped Unmanaged CRL
The EPA is proposing to identify chemical precipitation as BAT for
plants with discharges of pumped unmanaged CRL because it is both
technologically available and economically achievable for such plants.
The EPA identified seven plants with these types of discharges through
their corresponding CCR rule Corrective Action Plans pursuant to 40 CFR
part 257, subpart D. For these seven facilities, the EPA assumes no
additional costs for pumping equipment would be incurred under the
proposed options. The EPA did estimate the costs of treatment for these
seven facilities using the 2024 ELG cost model for chemical
precipitation. Thus, these costs reflect treating a known volume of
flow that has been shown to be adequate to meet the proposed numeric
effluent limitations for mercury and arsenic. The estimated total
annualized cost to industry at 3.76 percent average cost of capital for
these facilities is $121 million under Option 1 (see Table VII-1). The
EPA proposes that the costs incurred to meet the proposed arsenic and
mercury limitations based on chemical precipitation are economically
achievable for plants with existing discharges of pumped unmanaged CRL.
Finally, for discharges of pumped, unmanaged CRL, chemical
precipitation treatment represents reasonable further progress over the
BPT-level of control (surface impoundments).
VII. What are the benefits, costs and economic impacts of the proposed
revisions?
The EPA conducted two main types of analyses: economic impact
analysis addressing how many regulated entities are affected, and
benefit-cost analysis addressing the social benefits and costs
associated with the proposed ELG. This section provides an overview of
the methodology the EPA used to assess the social benefits and costs,
and the economic impacts and summarizes the results of these analyses.
``The Economic Analysis Memorandum for the Effluent Limitations
Guidelines and Standards for the Steam Electric Power Generating Point
Source Category--Unmanaged Combustion Residual Leachate'' (hereafter,
the Economic Analysis memo) in the docket provides additional detail
(DCN SE12127).
A. Introduction and Overview
In developing ELGs, and as required by CWA section 301(b)(2)(A),
the EPA evaluates the economic achievability of regulatory options to
assess the impacts of applying the limitations and standards to the
industry as a whole. For this proposal, the EPA compared the values to
a baseline that reflects implementation of existing environmental
regulations (as of this
[[Page 28503]]
proposal), including the 2024 ELG. Like the prior analyses of the 2015,
2020, and 2024 ELGs, the cost and economic impact analysis for this
proposed ELG focuses on understanding the magnitude and distribution of
compliance costs across the industry. With respect to broader market
impacts, because of data and methodological limitations, the EPA
conducted a screening analysis that assesses the direction and
magnitude of changes relative to other regulations that the EPA
determined would have small impacts and be economically achievable.
Specifically, the EPA analyzed the ratio of compliance costs to revenue
to see how the three main regulatory options change the number of
plants and their owning entities that exceed thresholds indicating
potential financial strain.
In addition to the analyses supporting the economic achievability
of the proposed regulatory options, the EPA conducted other analyses to
(1) characterize other potential impacts of the regulatory options
(e.g., on electricity rates), (2) determine the social benefits and
costs, and (3) determine broad impacts to small businesses to meet the
requirements of E.O.s or other statutes (e.g., E.O. 12866, Regulatory
Flexibility Act, Unfunded Mandates Reform Act).
B. Method for Estimating Compliance Costs
Compliance costs are the foundation for both economic achievability
and the cost side of the benefit-cost analysis. The EPA estimated
plant-specific compliance costs to control unmanaged CRL discharges at
steam electric plants to which the ELGs apply. The EPA assessed the
operations and treatment system components currently in place at a
given unit (or expected to be in place because of other existing
regulations, including the 2024 ELG and the 2015 CCR rule), identified
equipment and process changes that plants would likely make under each
of the three regulatory options presented in Table VI-1 of this
preamble, and estimated the capital and O&M costs to implement those
changes.
Because of uncertainty regarding which steam electric plants have
unmanaged CRL discharges and may therefore incur costs to meet effluent
limitations in this proposed ELG, the EPA used a bounding approach for
developing plant-level costs that considers factors indicative of the
potential for an unmanaged CRL discharge to be present, including (1)
the presence of landfills or surface impoundments that are not clean
closed or composite lined, (2) a total estimated groundwater pumping
rate greater than 0.5 gallons per minute (gpm), and (3) whether the
facility was undergoing corrective action for groundwater exceedances
based on the site's most recent groundwater monitoring reported in the
CCR database. The EPA solicits comment on all aspects of its
groundwater pumping rates estimates, including the use of single
groundwater pumping systems. See the Technical Support memo for
additional details (DCN SE12105).
The lower bound scenario considers a population of 63 plants
containing waste management units (landfills or surface impoundments)
that do not have a composite liner, are not clean closed, and report
undergoing corrective action for groundwater exceedances based on the
site's most recent groundwater monitoring reported in the CCR database.
All waste management units that fit these criteria from these 63 plants
were accounted for in the EPA's cost analysis and assumed a separate
treatment system for unmanaged CRL. For the upper bound scenario, the
EPA considered 111 plants with reported waste management units that are
not clean closed or composite lined but did not limit the waste
management units to those with corrective action. As a conservative
estimate and to better compare the upper and lower bound estimates, the
EPA calculated costs for all waste management units associated with the
111 plants and assumed a separate treatment system for each waste
management unit. In both scenarios, the EPA identified seven plants
where pumping and treatment of groundwater was selected as the
corrective remedy. These seven plants only received costing estimates
for treatment of unmanaged CRL and did not incur costs for pumping and
capturing unmanaged CRL in either the upper and lower bound
estimations, whereas the EPA calculated costs for the remaining 56 to
104 plants to include both pumping and treating unmanaged CRL.
Together, the results represent a reasonably estimated range of
nationwide costs of treatment for unmanaged CRL, but as discussed in
the following paragraphs, it could overestimate costs at some
facilities and underestimate costs at others. These modeling
assumptions should not be interpreted as a finding that any specific
site is subject to the unmanaged CRL limitations. Rather, these
assumptions should be considered as assisting in a reasonable
estimation of costs nationwide, with actual site-specific costs under-
or overestimated. While the EPA believes that using waste management
units that have triggered corrective action is a reasonable proxy for
estimating waste management units most likely to incur costs associated
with unmanaged CRL under this proposed ELG, the EPA notes that a
facility in corrective action for its groundwater contamination does
not mean that the waste management unit at issue would necessarily be
found to be a point source with a functional equivalent of a direct
discharge of unmanaged CRL to a WOTUS. Thus, in some cases, these costs
will be overestimated for specific facilities. At the same time, it may
be possible that unmanaged CRL may be subject to CWA permitting but
does not trigger corrective action under the 2015 CCR regulations.
In estimating private compliance costs, the EPA used the estimated
weighted average cost of capital for the industry of 3.76 percent to
annualize one-time costs and costs recurring on other than an annual
basis. For this analysis, the EPA annualized capital costs over the
useful life of the longest-lived technology installed at any plant (20
years) and annualized costs incurred on a non-annual, periodic basis
using the recurrence period (e.g., over 6 years for costs incurred
every six years). The EPA then calculated total industry costs by
summing plant-specific annualized costs.
The cost estimates presented in Table VII-1 are the total
annualized compliance costs associated with unmanaged CRL for the
industry as a whole. In comparison to similar estimates for the 2024
ELG, the Option 2 costs are higher than those presented in 2024,
reflecting the updates to the EPA's cost model and industry profile.
[[Page 28504]]
Table VII-1--Total Annualized Compliance Costs for Unmanaged CRL
[In millions, 2024$, at 2026]
--------------------------------------------------------------------------------------------------------------------------------------------------------
Total annualized compliance costs for unmanaged CRL (in millions)
-------------------------------------------------------------------------------------------------------
Option 1 Option 2 Option 3
-------------------------------------------------------------------------------------------------------
Lower bound Upper bound Lower bound Upper bound Lower bound Upper bound
--------------------------------------------------------------------------------------------------------------------------------------------------------
Total costs (pre-tax)........................... $121 $121 $658 $1,437 $1,076 $2,240
--------------------------------------------------------------------------------------------------------------------------------------------------------
For the assessment of industry costs, the EPA considered costs on
both a pre-tax and after-tax basis. Pre-tax annualized costs provide
insight on the total expenditure as incurred, while after-tax
annualized costs are a more meaningful measure of impact on privately
owned for-profit entities because they incorporate approximate capital
depreciation and other relevant tax treatments that reduce the net
compliance burden on entities that own the plants. Since taxes are
transfers, pre-tax costs reflect the real cost to society and are
appropriate for benefit-cost analysis. Similarly, after-tax costs are
reflective of private costs, which drive private decision-making, and
are therefore appropriate for use in economic impact analysis.
The cost estimates shown in Table VII-1 are an intermediate step to
producing the estimated incremental costs associated with this proposal
relative to the baseline which is full implementation of the 2024 ELG.
Table VII-2 summarizes the incremental costs of the three options as
compared to baseline; these costs represent the costs of this proposed
rule. Relative to the baseline, the preferred proposed ELG (Option 1)
results in after-tax annualized savings of $462 million and $1,104
million for the lower and upper bound scenarios, respectively. Option 2
results in no incremental costs because it represents the same
technology basis as the baseline.
Table VII-2--Estimated Incremental Costs Relative to the Baseline
--------------------------------------------------------------------------------------------------------------------------------------------------------
Annualized incremental costs (in millions)
-------------------------------------------------------------------------------------------------
Tax basis Option 1 Option 2 Option 3
-------------------------------------------------------------------------------------------------
Lower Bound Upper Bound Lower Bound Upper Bound Lower Bound Upper Bound
--------------------------------------------------------------------------------------------------------------------------------------------------------
Pre-Tax............................................... -$537 -$1,315 $0 $0 $418 $803
After-Tax............................................. -462 -1,104 0 0 350 668
--------------------------------------------------------------------------------------------------------------------------------------------------------
The EPA may, if new and relevant data are received on this proposed
ELG, quantify the costs of any final rule using the same models and
methodologies used here and in the 2020 and 2024 ELGs.
C. Method for Estimating Economic Impacts
The EPA assessed the economic impacts of this proposed ELG on
existing EGUs at steam electric plants and the entities that own those
plants, based on comparison of costs to revenue. The Economic Analysis
memo in the record (DCN SE12127) discusses these methods and results in
greater detail.
The EPA conducted the cost and economic impact analyses at both the
plant and parent company level. The first level provides insight on the
magnitude of compliance costs relative to the plant revenue derived
from electricity generation. The second level of analysis adds insight
on the impact of compliance requirements for entities that own multiple
plants. Having both levels of analysis is important because the impacts
could differ between these two levels. The cost and economic impact
analyses--at both the plant and parent company level--provide
screening-level indicators of the impacts of costs for unmanaged CRL
controls relative to historical operating characteristics of steam
electric plants incurring those costs (i.e., level of electricity
generation and revenue). The EPA conducted these analyses for baseline
and for the three regulatory options presented in Table VI-1 of this
preamble, then compared these impacts to understand the incremental
effects of the regulatory options in this proposal.
For each of the two levels of analysis (plant and parent entity),
the Agency assumed, for analytic convenience, that none of the
compliance costs would be passed on to consumers through electricity
rate increases and would instead be absorbed by the steam electric
plants and their parent entities. This assumption overstates the
impacts of compliance expenditures (or cost savings), as steam electric
plants that operate in a regulated market may pass on changes in
production costs to consumers through changes in electricity prices. If
the impacts are found to be economically achievable under the
assumption that no costs are passed to consumers, then the impacts will
be reduced--and also economically achievable--if entities have the
ability to pass along some costs to consumers.
1. Plant-Level Cost-to-Revenue Analysis
The EPA developed revenue estimates for this analysis using Energy
Information Administration (EIA) data. The EPA then calculated the
change in the annualized after-tax costs of the three regulatory
options presented in Table VI-1 of this preamble as a percent of
baseline annual revenues. The after-tax costs incorporate approximate
capital depreciation and other relevant tax treatments and are
therefore a more meaningful measure of the compliance impacts on
privately owned for-profit plants. Cost-to-revenue ratios are
screening-level indicators of potential economic impacts. EPA guidance
describes certain cost-to-revenue ratios for evaluating small entity
impacts under the Regulatory Flexibility Act (RFA) (U.S. EPA 2006). The
EPA used this guidance as the basis for also looking at impacts at the
level of the plants, following the approach used in previous ELG
regulatory analyses. Plants incurring costs below one percent of
revenue are unlikely to face economic impacts, while plants with costs
between one percent and three percent
[[Page 28505]]
of revenue have a higher chance of facing economic impacts, and plants
incurring costs above three percent of revenue have a still higher
probability of economic impact. Under the preferred proposed ELG
(Option 1), the EPA estimated that four plants, for both lower and
upper bound scenarios, would incur costs greater than or equal to one
percent of revenue, including three plants that have costs greater than
or equal to three percent of revenue. This represents a burden
reduction when compared to the 2024 ELG baseline, for which 33 and 78
plants are estimated to incur unmanaged CRL costs greater than one
percent of revenue, for the lower and upper bound scenarios,
respectively. The Economic Analysis memo in the record (DCN SE12127)
provides results for the other regulatory options the EPA analyzed.
This proposed rulemaking does not cause adverse impacts on small
entities. In fact, Option 1, the preferred option, is estimated to
result in fewer small entities incurring significant impacts. Between 5
and 11 fewer small entities will experience impacts exceeding one
percent of revenue as a direct result of this rule if finalized, and
between 4 and 6 fewer small entities will experience impacts exceeding
three percent of revenue.
2. Parent Entity-Level Cost-to-Revenue Analysis
The EPA also assessed the economic impact of the regulatory options
presented in Table VI-1 of this preamble at the parent entity level.
The screening-level cost-to-revenue analysis at the parent entity level
provides insight on the impact at the level of entities that own steam
electric plants. In this analysis, the domestic parent entity
associated with a given plant is defined as the entity with the largest
ownership share in the plant. For each parent entity, the EPA compared
the incremental change in the total annualized after-tax costs and the
total revenue for the entity to baseline. Following the methodology
employed in the analyses for the 2015, 2020 and 2024 ELGs, the EPA
considered a range of estimates for the number of entities owning an
existing EGU at a steam electric plant to account for partial
information available for steam electric plants that are not expected
to incur ELG compliance costs.
Like the plant-level analysis above, cost-to-revenue ratios provide
screening-level indicators of potential economic impacts, this time to
the owning entities; higher ratios suggest a higher probability of
economic impacts. The EPA estimated that the number of entities owning
existing EGUs at steam electric plants ranges from 209 to 373,
depending on the assumed ownership structure of those plants not likely
to incur ELG costs and not explicitly analyzed. The EPA estimates that
under the preferred proposed ELG (Option 1) and for the lower and upper
bound cost scenarios, two parent entities would incur annualized
unmanaged CRL costs representing one percent or more of their revenues,
with both of these entities incurring costs representing more than
three percent of revenue. This represents a burden reduction when
compared to the 2024 ELG baseline, for which nine and 22 parent
entities are estimated to incur unmanaged CRL costs greater than one
percent of revenue, with seven and 11 of these parent entities
estimated to incur costs greater than three percent of revenue.
Therefore, this proposed rulemaking does not have adverse impacts
on small entities or parent entities and Option 1, the preferred option
reduces impacts relative to the baseline option.
D. Estimated Annual Costs of the Proposed Regulatory Options/Scenarios
The estimated annual costs of the proposed ELG refers to social
costs, which are the costs of the proposed ELG from the viewpoint of
society as a whole, rather than the viewpoint of regulated plants and
owning entities (which are private costs). In calculating social costs,
the EPA used the pre-tax costs, as these costs represent the total
expenditures irrespective of any adjustments to reflect depreciation
and other relevant tax treatments. The EPA tabulated these costs in the
year they are estimated to be incurred, which varies across plants
based on the estimated compliance year. These estimated annual costs
are also the costs used in the benefit-cost analysis.
For the analysis of social costs, the EPA estimated a plant- and
year-explicit schedule of technology implementation cost outlays that
reflects the ``no later than date'' for each option. For the baseline
and Option 2, the schedule is based on plant owners installing
technologies to meet the applicable limitations no later than the end
of 2029. For Options 1 and 3, the deadline is December 2034. As
described in section 3.1, of the Economic Analysis Memo, the EPA
assumed that plants would implement technologies over several years
leading to this deadline as their permits are renewed to incorporate
the applicable limitations. For the baseline and Option 2, technology
implementation years run from 2027 through 2029. For Options 1 and 3,
the technology implementation years run from 2030 through 2034. The
useful life of the technology extends for 20 years past the last year
of technology installation. Thus, the full analysis period for all
options for the estimation of social costs is 28 years: 2027-2054. As
described further in the Economic Analysis memo to the record (DCN
SE12127), the increases in the cost to state governments to develop
NPDES permits based on the permitting authority's BPJ instead of the
limitations specified in the baseline are small, particularly when
compared to compliance costs. Consequently, the social costs are
predominantly based on the pre-tax costs estimated for steam electric
plants.
Table VII-3 of this preamble presents the incremental total
annualized social costs of the three regulatory options, compared to
baseline and calculated using three percent and seven percent discount
rates. The preferred proposed ELG (Option 1) has estimated social costs
savings of $446 million to $1,090 million using a three percent
discount rate and $532 million to $1,286 million using a seven percent
discount rate.
Table VII-3--Estimated Incremental Total Annualized Social Costs Relative to the Baseline
--------------------------------------------------------------------------------------------------------------------------------------------------------
Annualized social costs (in millions)
-------------------------------------------------------------------------------------------------
Discount rate Option 1 Option 2 Option 3
-------------------------------------------------------------------------------------------------
Lower bound Upper bound Lower bound Upper bound Lower bound Upper bound
--------------------------------------------------------------------------------------------------------------------------------------------------------
3% Discount Rate...................................... -$446.2 -$1,089.8 $0 $0 $375.6 $715.7
7% Discount Rate...................................... -531.9 -1,286.3 0 0 250.5 475.2
--------------------------------------------------------------------------------------------------------------------------------------------------------
[[Page 28506]]
E. Economic Achievability
In developing ELGs, and as required by CWA section 301(b)(2)(A),
the EPA evaluates economic achievability to assess the impacts of
applying the limitations and standards on the industry as a whole. As
described in more detail below, the proposed rule is expected to allow
flexibility for permitting authorities to develop BAT limitations for
certain discharges of unmanaged CRL using their best professional
judgment, considering site-specific factors. The EPA estimates that
this flexibility will result in cost savings when compared to the
baseline and will allow compliance decisions that impose minimum
economic impact across the industry and customers. As noted in section
VI.B, the same approach cannot be used to assess economic achievability
for open and closed facilities; nonetheless, it is the combination of
effects that determines economic achievability to the industry as a
whole.
The EPA cannot prospectively determine how many or which instances
of unmanaged CRL discharged through groundwater may ultimately be found
to require CWA permits. As described above, to be a covered by the
NPDES Program, there must be a discharge (or functionally equivalent
discharge) of a pollutant from a point source into a WOTUS. To ensure
that technology costs are economically achievable for the proposed
options, the EPA assumed a worst-case costing scenario based on the
upper bound set of facilities. The EPA's assumption for the purposes of
a worst-case costing analysis does not mean the EPA views all of these
potential discharges as requiring CWA permitting. Instead, total costs
(and pollutant loadings) provide the range within which actual costs
(and pollutant loadings) are expected to fall. The EPA acknowledges
that a best estimate would be helpful, but in the absence of
determinations on which discharges are subject to CWA permitting, the
EPA cannot definitively define the ultimate scope of coverage. This
position is consistent with the position outlined above. In this
proposal, the EPA has made a reasonable estimation of costs, fulfilling
the Agency's rulemaking requirements. Using these costs, the EPA then
conducted a screening-level analysis of economic impacts, which helps
inform the EPA's proposed determination that the unmanaged CRL
limitations reflected in the preferred proposed option (Option 1) are
economically achievable. For further discussion of the screening-level
analysis and economic achievability, see sections VII.A through VII.D
of this preamble.
Impacted Businesses
Relative to the baseline, the proposed ELG is estimated to reduce
compliance costs for steam electric plants that have unmanaged CRL
discharges determined to be the functional equivalent of a direct
discharge to a WOTUS by their permitting authority. Under the baseline,
the EPA estimates that a total of 808 plants are subject to the steam
electric point source category overall and that, in the baseline, 20 to
41 plants would incur cost-to-revenue ratios greater than 3 percent for
unmanaged CRL costs under the lower and upper bound cost scenarios,
respectively. Of these plants, seven to 10 plants are owned by small
entities under the lower and upper bound scenarios, respectively. An
additional 13 to 37 plants incur unmanaged CRL costs greater than 1
percent (but less than 3 percent) of revenue in the baseline under the
lower and upper bound cost scenarios.
The preferred proposed ELG (Option 1) significantly reduces these
baseline impacts. As detailed in section VIII below, the EPA estimated
that, under the proposed ELG, a total of three plants (i.e., 17 to 38
fewer plants than in the baseline for the corresponding scenarios) may
incur compliance costs greater than three percent of revenue, including
two plants owned by small entities. Only one plant, owned by a large
entity, incurs unmanaged CRL costs between 1 and 3 percent of revenue.
The Economic Analysis memo in the docket provides additional detail
(DCN SE12127).
F. Impacts on Residential Electricity Prices
The EPA presents the effects of the proposed ELG on consumers in
the Economic Analysis memo to the record (DCN SE12127). While the CWA
section 304(b) ``consideration'' factors do not require these details,
the EPA presents them for informational purposes. To consider all
scenarios where cost savings are passed on partially to electricity
consumers, the EPA made an inclusive assumption based on all cost
savings being passed on to electricity consumers, even though this is
unlikely in reality. If all annualized compliance cost savings were
passed on to residential consumers of electricity instead of being
retained by the operators and owners of power plants (following the
same assumption the EPA has made for analytic convenience for all prior
steam electric rulemaking analyses), the average yearly electricity
bill for a typical household would be $1.38 to $3.37 lower under the
preferred proposed ELG (Option 1) as compared to the baseline. These
results represent the largest cost savings that would be realized by
households.
G. Benefit-Cost Analysis
The proposed rule is estimated to result in avoided social costs of
$446 million to $1,090 million in 2024 dollars under the lower and
upper bound scenarios (at a three percent discount rate). The proposed
rule will also lead to forgone benefits in cases where site-specific
considerations result in the permitting authority developing less
stringent limitations using its BPJ than the limitations that apply
under the baseline, but the EPA expects the forgone benefits to be
lower than the cost savings and therefore estimates the proposed rule
to provide net benefits. More details on benefits are provided in
section XI.
VIII. Pollutant Loadings
In developing ELGs, the EPA typically evaluates the pollutant
loading reductions of regulatory options to assess the impacts of the
compliance requirements on discharges from the whole industry. The EPA
took the same approach to the one described above for plant-specific
costs for estimating pollutant reductions associated with this
proposal. That is, the EPA compared the values to a baseline that
reflects implementation of existing environmental regulations, namely
the 2024 ELG for unmanaged CRL.
The general methodology that the EPA used to calculate pollutant
loadings in this proposed ELG is the same as that described in the 2024
ELG. The EPA first estimated--on an annual, per plant basis--the
pollutant discharge load associated with the technology basis evaluated
for plants to comply with the 2024 ELG requirements for unmanaged CRL.
The EPA similarly estimated plant-specific post-compliance pollutant
loadings as the load associated with the technology bases for plants to
comply with effluent limitations based on each regulatory option in
this proposed rule. For each regulatory option, the EPA then calculated
the changes in pollutant loadings at a particular plant as the sum of
the differences between the estimated baseline and post-compliance
discharge loadings for unmanaged CRL.
A. Unmanaged Combustion Residual Leachate
For unmanaged CRL, the EPA used the average pollutant effluent
concentrations and plant-specific discharge flow rates to estimate the
[[Page 28507]]
mass pollutant discharge per plant for the baseline and the proposed
options. The EPA used plant population data compiled for the 2024 ELG
as the initial basis for estimating discharge flow rates and updated
the population to reflect changes in plant retirement status. As
discussed in the Technical Support memo (DCN SE12105), the plants that
indicated retirement by the end of 2025 were not included in the
analysis. The EPA solicits comment on the exclusion of retired plants
from the analysis given that such plants are still expected to incur
costs associated with treatment of unmanaged CRL.
The EPA also used utilities' ``CCR Rule Compliance Data and
Information'' websites to identify waste management units that may
discharge unmanaged CRL. For discharges of unmanaged CRL, the EPA
estimated the volume of leachate-laden groundwater captured from
pumping systems that draw down the groundwater elevation along the
hydraulically downgradient cross-sectional width of the CCR management
unit. See the Technical Support memo for additional details (DCN
SE12105).
The EPA assigned pollutant concentrations based on current
operating conditions or treatment in place for baseline and the
operation of a treatment system designed to comply with the proposed
options. To represent the average pollutant concentrations for
unmanaged CRL, the EPA used average pollutant concentrations for CRL
calculated from data compiled from the 2015 ELG and 2024 ELG. However,
due to the lack of pollutant concentration data available for each
analyte in unmanaged CRL, as well as the highly variable impact of
ambient groundwaters on pollutant concentrations in unmanaged CRL, only
total suspended solids (TSS) and total dissolved solids (TDS) were
calculated for pollutant loadings. The selection of TSS and TDS ensures
that the sum of these two metrics does not double count other
pollutants that potentially may be present in unmanaged CRL, which the
EPA is unable to numerically quantify due to lack of available data.
The EPA did not make assumptions about ambient TSS and TDS
concentrations in groundwater when calculating the pollutant loadings;
however, data collected from groundwater monitoring reports suggest
that TDS concentrations for CRL and groundwater are generally similar
(DCNs SE12135 and SE12105).
To estimate pollutant removal associated with chemical
precipitation, the EPA first transferred the average flue gas
desulfurization effluent concentrations for chemical precipitation to
CRL, as it did in the 2015 ELG. The EPA then transferred the untreated
and chemical-precipitation treated average pollutant concentrations for
TSS and TDS from CRL to unmanaged CRL. For the spray dry evaporator
treatment option, the EPA assumed that the pollutant loadings would be
reduced to zero since the technology would facilitate zero-discharge.
B. Summary of Incremental Changes of Pollutant Loadings
Table VIII-1 of this preamble summarizes the net reduction to
annual pollutant loadings, compared to baseline, associated with each
regulatory option in Table VI-1 of this preamble. The estimated
pollutant loading in Option 1 includes only calculations from seven
plants that the EPA identified as discharging unmanaged CRL that is
mixed with groundwater before being captured and pumped to the surface
before discharge directly to a WOTUS. The EPA did not include estimates
from plants that may have discharges of unmanaged CRL that the
permitting authority determines are the functional equivalent of a
direct discharge to WOTUS, which would be subject to BAT limitations
based on BPJ under Option 1. The EPA cannot predict which plants will
be determined to have a functional equivalent direct discharge or the
resulting requirements based on the permitting authority's BPJ. Thus,
the EPA cannot estimate pollutant loadings post implementation at those
plants and cannot include those plants in these estimates.
Table VIII-1--Estimated Incremental Reductions in Annual Pollutant Loading Compared to the Baseline for
Regulatory Options 1, 2, and 3
[In millions of pounds/year]
----------------------------------------------------------------------------------------------------------------
Incremental change in pollutant loading
-----------------------------------------------------------------------------
Option 1 Option 2 Option 3
-----------------------------------------------------------------------------
Lower Upper
Upper bound bound Lower bound bound Lower bound Upper bound
----------------------------------------------------------------------------------------------------------------
Pollutant Loading (millions of -12.9 -29.8 0 0 584 1,190
pounds/year).....................
----------------------------------------------------------------------------------------------------------------
Note: Reductions in pollutant loadings are rounded to three significant figures.
IX. Non-Water Quality Environmental Impacts
The elimination or reduction of one form of pollution may create or
aggravate other environmental problems. Therefore, sections 304(b) and
306 of the CWA require the EPA to consider non-water quality
environmental impacts (including energy requirements) associated with
ELGs. These non-water quality environmental impacts are especially
important due to the energy crisis and rising demands for energy and
reliability in the U.S., as discussed in section V.C. Accordingly, the
EPA has considered the potential impacts of this proposed ELG on energy
consumption, air emissions, solid waste generation, and changes in
water use. In general, to conduct this analysis, the EPA used the same
methodology (with updated data as applicable) as it did for the
analyses supporting the 2024 ELG. The following sections summarize the
methodology and results. See the Technical Support Memo for additional
details (DCN SE12105).
A. Energy Requirements
Steam electric power plants use energy when transporting ash and
other solids on or off site, operating wastewater treatment systems
(e.g., pumping, chemical precipitation, spray dry evaporators), or
operating ash handling systems. For this proposal, the EPA considered
whether there would be an associated change in the incremental energy
requirements for treatment of unmanaged CRL compared to the baseline.
Energy requirements vary depending on the regulatory option evaluated
and the current operations of the facility. Therefore, as applicable,
the EPA estimated the energy usage in MWh for treatment equipment added
to the plant systems or in gallons of fuel consumed for transportation/
operating equipment and summed the facility-specific estimates to
calculate the net
[[Page 28508]]
change in energy requirements from baseline for the regulatory options.
The EPA estimated the amount of energy needed to operate wastewater
treatment systems based on the horsepower ratings of the pumps and
other equipment. The EPA also estimated any changes in the fuel
consumption associated with transporting solid waste from steam
electric power plants to landfills (on- or off-site). The frequency and
distance of transport depend on a plant's operation and configuration;
specific factors include the volume of waste generated and the
availability of either an on-site or off-site nonhazardous landfill and
its distance from the plant. Table IX-1 of this preamble shows the net
change in annual electrical energy usage associated with the regulatory
options compared to the baseline, as well as the net change in annual
fuel consumption requirements associated with the three regulatory
options compared to the baseline. The estimated energy and fuel usage
in Option 1 includes only calculations from seven plants that the EPA
identified as discharging unmanaged CRL that is mixed with groundwater
before being captured and pumped to the surface and discharged directly
to a WOTUS. The EPA did not include estimates from plants that may have
discharges of unmanaged CRL that the permitting authority determines
are the functional equivalent of a direct discharge to WOTUS, which
would be subject to BAT limitations based on BPJ under Option 1.
Table IX-1--Estimated Incremental Change in Annual Energy Requirements Compared to the Baseline Associated With Regulatory Options
--------------------------------------------------------------------------------------------------------------------------------------------------------
Energy use associated with regulatory options
---------------------------------------------------------------------------------------
Non-water quality environmental impact Option 1 Option 2 Option 3
---------------------------------------------------------------------------------------
Lower bound Upper bound Lower bound Upper bound Lower bound Upper bound
--------------------------------------------------------------------------------------------------------------------------------------------------------
Incremental change in electrical energy usage (MWh)............. -133,000 -319,000 0 0 2,050,000 4,160,000
Incremental change in fuel (thousand gallons)................... -185 -296 0 0 766 1,054
--------------------------------------------------------------------------------------------------------------------------------------------------------
B. Air Pollution
The three proposed regulatory options are expected to affect air
pollution through two main mechanisms: (1) changes in auxiliary
electricity use by steam electric power plants due to the need to
operate wastewater treatment; and (2) changes in transportation-related
emissions due to the trucking of solid waste to landfills. This section
discusses air emission changes associated with these mechanisms as they
relate to treatment of unmanaged CRL and presents the corresponding
estimated total and net changes in air emissions.
Steam electric power plants generate air emissions from operating
transport vehicles, such as dump trucks, which release criteria air
pollutants and GHGs. A decrease in energy use or vehicle operation
would result in decreased air pollution and emissions.
To estimate the air emissions associated with changes in electrical
energy use projected as a result of the regulatory options in this
proposal compared to baseline, the EPA combined the energy usage
estimates with air emission factors associated with electricity
production to calculate air emissions associated with the incremental
energy requirements. The EPA estimated nitric oxide + nitrogen dioxide
(NOX) and sulfur dioxide (SO2) emissions using plant- or NERC-specific
emission factors (tons/MWh) obtained from a 2024 Rule run of IPM for
run year 2035.
To estimate air emissions associated with the operation of
transport vehicles, the EPA used the MOVES4.0 model to identify air
emission factors (tons/mile) for the air pollutants of interest. The
EPA estimated the annual number of miles that dump trucks moving
wastewater treatment solids to on- or off-site landfills would travel
for the regulatory options. The EPA used these estimates to calculate
the net change in air emissions for the three regulatory options. Table
IX-2 presents the estimated net change in air emissions associated with
auxiliary electricity and transportation for the proposed options. The
estimated air emissions in Option 1 include only calculations from
seven plants that the EPA identified as discharging unmanaged CRL that
is mixed with groundwater before being captured and pumped to the
surface before discharge directly to a WOTUS. The EPA did not include
estimates from plants that may have discharges of unmanaged CRL that
the permitting authority determines are the functional equivalent of a
direct discharge to WOTUS, which would be subject to BAT limitations
based on BPJ under Option 1.
Table IX-2--Estimated Net Change in Industry-Level Air Emissions Compared to the Baseline Associated With Auxiliary Electricity and Transportation for
Options
--------------------------------------------------------------------------------------------------------------------------------------------------------
Air Emissions associated with regulatory options
---------------------------------------------------------------------------------------
Non-water quality environmental impact Option 1 Option 2 Option 3
---------------------------------------------------------------------------------------
Lower bound Upper bound Lower bound Upper bound Lower bound Upper bound
--------------------------------------------------------------------------------------------------------------------------------------------------------
Incremental change in NOX (thousand tons/year).................. -0.01 -0.02 0 0 0.12 0.23
Incremental change in SO2 (thousand tons/year).................. -0.01 -0.02 0 0 0.10 0.21
--------------------------------------------------------------------------------------------------------------------------------------------------------
[[Page 28509]]
C. Solid Waste Generation
Steam electric power plants generate solid waste associated with
sludge from wastewater treatment systems when treating unmanaged CRL
(e.g., chemical precipitation, SDE). The EPA estimated the total and
incremental change in the amount of solids generated for each plant
compared to baseline under each regulatory option. Table IX-3 of this
preamble shows the net change in annual solid waste generation,
compared to baseline, associated with the three regulatory options. The
estimated solid waste generation in Option 1 includes only calculations
from seven plants that the EPA identified as discharging unmanaged CRL
that is mixed with groundwater before being captured and pumped to the
surface and discharged directly to a WOTUS. The EPA did not include
estimates from plants that may have discharges of unmanaged CRL that
the permitting authority determines are the functional equivalent of a
direct discharge to WOTUS, which would be subject to BAT limitations
based on BPJ under Option 1.
Table IX-3--Estimated Incremental Changes to Solid Waste Generation Compared to the Baseline Associated With
Regulatory Options
----------------------------------------------------------------------------------------------------------------
Solid waste generation associated with regulatory options
-----------------------------------------------------------------------------
Non-water quality environmental Option 1 Option 2 Option 3
impact -----------------------------------------------------------------------------
Upper Upper
Lower bound bound Lower bound bound Lower bound Upper bound
----------------------------------------------------------------------------------------------------------------
Incremental change in solids -1,320,000 -3,03 0 0 4,320,000 8,780,000
generated (tons/year)............ 0,000
----------------------------------------------------------------------------------------------------------------
D. Changes in Water Use
The EPA does not expect a change in water use associated with the
treatment technology options (chemical precipitation, spray dry
evaporation) considered for the treatment of unmanaged CRL for the
proposed regulatory options. However, treatment of unmanaged CRL
associated with Option 2 and Option 3 requires pumping and capturing
the unmanaged CRL before treatment can be implemented. Furthermore, in
some cases, additional wellheads would be installed to pump clean water
into the groundwater to help push the groundwater in the desired
direction. Because the nature of unmanaged CRL is highly site-specific,
pumping unmanaged CRL could potentially involve large amounts of
groundwaters that are mixed with unmanaged CRL. As a result,
groundwater reservoirs could be depleted through treatment of unmanaged
CRL, which may impact downstream drinking water sources that rely on
groundwater reservoirs. For this proposed ELG, the EPA estimated the
total volume of leachate-laden groundwater that could be pumped
annually across the industry may be between 20 billion to 41 billion
gallons for the lower and upper bound estimations, respectively, for
Options 2 and 3. Furthermore, as discussed earlier in section VI, this
volume could be an underestimation, as the EPA does not have data to
determine the exact volume of groundwater that might need to be pumped
to fully address the functional equivalent of a direct discharge.
Therefore, the proposed Options 2 and 3 could have a substantial impact
on water usage by depleting groundwater reservoirs when capturing
unmanaged CRL for treatment. Option 1 is based on site-specific BPJ
analyses conducted by the permitting authority, and plants may have
very different sets of requirements that impact their potential water
usage. As a result, the EPA cannot accurately predict post-
implementation water usage for Option 1.
X. Environmental Assessment and Benefits
A. Introduction
This section summarizes the potential environmental and human
health effects and benefits due to changes in unmanaged CRL discharges
from steam electric power plants. An environmental assessment memo in
the record provides additional details on these analyses (DCN SE12102),
including a qualitative comparison of the change in impacts associated
with the proposed rule regulatory options to those projected under the
baseline; specifically, it presents information from the EPA's review
of the scientific literature of impacts of pollutants discharged from
unmanaged CRL on human health and the environment. The 2015 EA (EPA-
821-R-15-006), 2020 EA (EPA 821-R-20-002), and 2024 EA (EPA-821-R-24-
005) provide information from the EPA's earlier review of the
scientific literature and of documented cases of the impacts on human
health and the environment associated with the wider range of steam
electric power plant wastewater discharges addressed in earlier rules.
Current scientific literature indicates that untreated steam
electric power plant wastewaters, including unmanaged CRL, contain
large amounts of a wide range of pollutants, some of which are toxic
and bioaccumulative and cause detrimental environmental and human
health impacts. To the extent that the proposed rule results in less
stringent treatment of unmanaged CRL from certain facilities than under
the 2024 baseline, there would be forgone benefits from forgone water
quality improvements and the associated human health, ecological and
use and non-use effects, and market and productivity benefits.
For additional information, see section X of the environmental
assessment memo (DCN SE12102). The EPA also considered environmental
and human health effects associated with changes in air emissions,
solid waste generation, and energy usage.
B. Updates to the Environmental Assessment Methodology
For this proposal, the EPA updated the environmental assessment
methodology to focus on a qualitative evaluation of potential
environmental and human health impacts associated with unmanaged CRL.
This approach reflects the nature of the available data and the
objectives of the environmental assessment, which are to identify
pathways of exposure, characterize potential receptors, and evaluate
the relative magnitude of impacts under existing regulations and the
proposed regulatory options.
The qualitative assessment integrates information from multiple
lines of evidence, including facility operating practices,
hydrogeologic settings, reported monitoring data, peer reviewed
literature, and prior EPA analyses of coal combustion residuals. Due to
the unique nature of unmanaged CRL mixing with subsurface groundwater,
site-specific concentrations are limited or variable, therefore EPA
relied on
[[Page 28510]]
bounding analyses to assess the likelihood and direction of potential
impacts.
C. Outputs From the Environmental Assessment
The EPA evaluated the potential environmental and ecological
changes associated with anticipated changes in pollutant loadings under
the proposed rule. As described in the environmental assessment memo to
the record, the analysis focuses on changes in environmental and human
health impacts resulting from exposure to toxic and bioaccumulative
pollutants, with particular attention to surface water pathways and
groundwater to surface water connections. The environmental assessment
memo provides a qualitative summary of the potential environmental and
human health effects of the proposed limitations on discharges of
unmanaged CRL, including summaries of the potential pollutant effects
of total dissolved solids (TDS) and total suspended solids (TSS) in
receiving and downstream waters. The EPA also evaluated environmental
and human health effects of other environmental changes such as changes
to air emissions, solid waste generation, and energy usage.
D. Benefits
This section summarizes the national environmental benefits due to
changes in unmanaged CRL discharges from steam electric power plants.
The Economic Analysis memo in the record provides additional details on
the benefits analyses (DCN SE12127).
Following the approach used in prior steam electric rulemakings,
the benefit categories associated with the proposed rule regulatory
options fall into four broad categories: (1) human health benefits from
surface water quality improvements, (2) ecological conditions and
recreational use effects from surface water quality changes, (3) market
and productivity benefits, and (4) air-related effects. Data
limitations, modeling limitations, and gaps in the understanding of how
society values certain environmental changes expected to result from
changes to unmanaged CRL discharges prevented the EPA from quantifying
and monetizing the benefits of this proposed rule. The EPA assessed
benefits qualitatively, indicating their direction and potential
magnitude where possible.
The following section summarizes the EPA's analysis of the benefit
categories the Agency was able to identify to various degrees. The
analysis builds on the environmental assessment summarized in section
IX and detailed in the record (see DCN SE12102).
1. Qualitative Analysis of Benefits
The EPA estimates that the proposed rule may change the incidence
of adverse health effects from exposure to metals and toxic pollutants
in unmanaged CRL through the ingestion of self-caught fish (e.g.,
arsenic, mercury, lead) or drinking water (e.g., trihalomethanes from
bromide in source waters). The EPA did not quantify changes in loadings
for metals and toxic pollutants, but the environmental assessment
identifies resources affected by unmanaged CRL discharges that indicate
potential pathways of human exposure to unmanaged CRL pollutants.
The proposed rule is expected to result in surface water quality
changes including changes in aquatic and wildlife habitat, water-based
recreation (e.g., fishing, swimming, boating, and near-water
activities), aesthetic value, and nonuse value from changes in
ecosystem health. For some receiving waters, where a permitting
authority establishes case-by-case BAT limitations based on
technologies more advanced than chemical precipitation, the proposed
rule may result in changes in improved habitat conditions for plants,
invertebrates, fish, and amphibians, and the wildlife that prey on
aquatic organisms, including enhanced protection of threatened and
endangered species.
By changing discharges of total suspended sediment that contribute
to turbidity, the proposed rule may also result in changes in water
treatment costs for municipal drinking water systems located downstream
from steam electric plant impoundments or landfills that have unmanaged
CRL. Changes in sediment discharge may affect sedimentation in
reservoirs and navigable waters and alter the frequency of maintenance
dredging.
Under the preferred option (Option 1), effluent limitations would
be established on a site-specific basis using the permitting
authority's BPJ, and resulting compliance measures and costs may differ
from those assumed in the 2024 ELG baseline and the regulatory options
analyzed for this proposal. In some cases, permitting authorities may
determine that less extensive controls are appropriate given site-
specific conditions, which could lower compliance costs as compared to
the baseline but also reduce pollutant load reductions and the
associated environmental benefits (i.e., result in forgone benefits
when compared to the baseline). In other cases, site-specific
information may support more stringent controls, particularly where
unmanaged CRL discharges have a clear connection to surface water
exposure pathways, potentially resulting in greater environmental and
human health benefits than previously anticipated (as well as possibly
greater compliance costs).
The magnitude of potential benefits is uncertain and depends on the
number of plants with unmanaged CRL discharges that meet the definition
of a functionally equivalent discharge under the ELGs, and any eventual
limitations set by permitting authorities based on BPJ. However, even
to the extent that the proposed rule results in less stringent
limitations for all plants where BPJ will apply, as EPA conservatively
assumed under both the lower and upper bound cost scenarios, the EPA
estimates the forgone benefits of the proposed rule to be less than the
substantial cost savings the Agency estimated.\7\
---------------------------------------------------------------------------
\7\ The proximity analysis similarly indicates that differences
in potential impacts to sensitive receptors (impaired waters,
drinking water resources, and habitats for threatened and endangered
species) are minimal or uncertain relative to the baseline. In
contrast, the costs associated with maintaining to expanding
treatment requirements (chemical precipitation or zero discharge)
are more quantifiable and substantial.
---------------------------------------------------------------------------
XI. Implementation
A. Continued Implementation of Existing Limitations and Standards
The EPA has continually stressed since the announcement of the
proposed supplemental 2024 ELG that the existing 40 CFR part 423
limitations and standards in effect continue to apply. In the sections
below, the EPA discusses considerations for permitting authorities and
regulated entities as they continue to implement existing regulations
and look ahead to any final rule.
B. Implementation of New Limitations and Standards
Under the preferred option, EPA would modify section 423.13 to
clarify that any new unmanaged CRL BAT requirements would not extend to
retired plants closed by the effective date of the 2024 ELG. A new
definition at section 423.11(gg) would define the term ``closed coal
combustion residual waste management unit'' as a landfill or
impoundment that no longer receives coal combustion residuals or other
wastes as of the effective date of the 2024 ELG (i.e., July 8, 2024).
The term closed coal combustion residual waste management unit is
defined to provide clarity and help avoid confusion over what
``closed'' means in this situation. For example, precipitation could
enter
[[Page 28511]]
impoundments and lead to the generation of unmanaged CRL long after the
EGU has ceased coal combustion and the impoundment has stopped
receiving coal combustion residuals. In these instances, the proposed
rule would direct the permitting authority to establish BAT limitations
on a case-by-case basis using BPJ. The EPA is proposing these updates
to the regulation in response to stakeholder input. This definition
reflects the EPA's previous implementation of the 2015 and 2024 ELGs,
and codifying it in the regulatory text would provide clarity to
permitting authorities and certainty for the regulated community.
C. Reporting and Recordkeeping Requirements
As discussed in section VI of this preamble, CRL can be discharged
not only as an end-of-pipe discharge, but also through groundwater, and
the EPA is proposing revised BAT limitations for a subcategory of
electric generating units that includes those with discharges of CRL
that a permitting authority determines are the functional equivalent of
direct discharges of CRL to a WOTUS. The requirements in the 2024 ELG
for annual reporting and recordkeeping requirements will continue to
facilitate the permitting authorities' review of such discharges. These
existing requirements also facilitate compliance monitoring and make
compliance information available to the public. The existing
information collection request (ICR) that was published along with the
2024 ELG already includes all of the information necessary to comply
with the proposed revised BAT limitations. The EPA expects that the
burden of this ICR will decrease as fewer facilities will be subject to
its requirements.
D. Site-Specific Water Quality-Based Effluent Limitations
EPA regulations at 40 CFR 122.44(d)(1), implementing section
301(b)(1)(C) of the CWA require each NPDES permit to include any
requirements, in addition to or more stringent than ELGs or standards
promulgated pursuant to sections 301, 304, 306, 307, 318, and 405 of
the CWA, necessary to achieve water quality standards established under
section 303 of the CWA, including state narrative criteria for water
quality. Those same regulations require that limitations must control
all pollutants or pollutant parameters (either conventional,
nonconventional, or toxic pollutants) that the Director determines are
or may be discharged at a level that will cause, have the reasonable
potential to cause, or contribute to an excursion above any state water
quality standard, including state narrative criteria for water quality
(40 CFR 122.44(d)(1)(i)).
The preamble to the 2015 rule discussed bromide as a parameter for
which water quality-based effluent limitations may be appropriate. The
EPA stated its recommendation that permitting authorities carefully
consider whether water quality-based effluent limitations for bromide
or TDS would be appropriate for FGD wastewater discharged from steam
electric power plants upstream of drinking water intakes. The EPA also
stated its recommendation that the permitting authority notify any
downstream drinking water treatment plants of the discharge of bromide.
To the extent there are covered discharges of unmanaged CRL to a WOTUS,
the EPA continues to recommend that permitting authorities carefully
consider whether water quality-based effluent limitations are
appropriate.
E. Severability
The purpose of this section is to clarify the EPA's intent with
respect to the severability of provisions of any final rule based on
this proposed rule. In the event of a stay or invalidation of part of
any final rule based on this proposed rule, the Agency's intent is to
preserve the remaining portions of the rule to the fullest extent
possible. The EPA notes the following existing regulatory text at 40
CFR 423.10(b) that would not be altered by this proposed rule: ``The
provisions of this part are separate and severable from one another. If
any provision is stayed or determined to be invalid, the remaining
provisions shall continue in effect.'' Moreover, to dispel any doubt
regarding the EPA's intent and to inform how any final regulation would
operate if severed, the Agency proposes to find that it would adopt
each portion of this proposed rule independent of the other portions.
As explained below, the EPA carefully crafted this proposed rule so
that each provision or element of a final rule based on this proposed
rule can operate independently. Moreover, the EPA has organized the
proposed rule so that if any provision or element of a final rule based
on this proposed rule is determined by judicial review or operation of
law to be invalid, that partial invalidation would not render the
remainder of the rule invalid.
The three options in this proposed rule propose to regulate
discharges associated with two types of unmanaged CRL discharges. Each
proposed option would, if finalized, provide limitations and standards
associated with each type of unmanaged CRL, which are independent of
one another. This is because the EPA considers the BAT statutory
factors for each type of discharge independently. For example, if
proposed Option 1 were finalized and the limitations established for
functionally equivalent direct discharges of unmanaged CRL were deemed
invalid, the EPA's view is that this would not impact the separate
limitations established for discharges of unmanaged CRL that is
captured and pumped to the surface.
XII. Data Request
The EPA solicits comment providing specific data and information to
the Agency to support the analysis of other wastestreams in any
subsequent reconsideration action. Specifically, the EPA solicits
comment on facilities or electric generating units missing from the
industry profile, updated flue gas desulfurization flow rates, CRL flow
rates at new post-2015 waste management units, and pilot test
performance data as further described below.
Industry Profile
Some electric utilities have suggested that the industry profile
utilized in the 2024 ELG was missing facilities or electric generating
units for one or more wastestreams. The EPA solicits information for
any facility or electric generating unit with one or more of the 2024
ELG wastewaters but was not evaluated for costs and pollutant loadings
for that wastewater in the 2024 ELG rule record. Specifically, the EPA
solicits comment on the facility name, the relevant electric generating
unit, the wastewater(s) missing from the 2024 ELG rule analysis, and an
explanation of why the Agency's 2024 ELG rule record information and
assumptions were either incorrect or are no longer accurate.
Updated Flue Gas Desulfurization Flow Rates
The Electric Power Research Institute comments on the 2025 Deadline
Extension proposed rule suggest that the EPA's flow rate data may be
stale and in need of updating. The EPA solicits comment providing
information that would confirm or refute this statement. Specifically,
to ensure that the EPA can compare, and potentially replace, data
collected as part of the 2010 survey, for each wet flue gas
desulfurization scrubber in service at a plant, the Agency solicits
comment on the following updated information:
[[Page 28512]]
The steam electric generating units, and nameplate
capacity, serviced by the flue gas desulfurization scrubber.
The amount of flue gas desulfurization scrubber purge (or
slurry discharge) sent to wastewater treatment or discharge for the
last two years (2024 and 2025), specifically:
[cir] Typical flowrate in gpm or gallons per day (gpd), including
duration and frequency of flue gas desulfurization scrubber purge (or
slurry discharge) generation (hours per day and days per year).
[cir] Design (i.e., maximum) flowrate (gpm or gpd) for existing
wastewater treatment, including the number of days the wastewater
treatment system operated at the design flowrate (if the system had not
operated at design flow rate during this time period, a comment should
characterize the highest flow rate observed and other relevant
information for characterizing operations above the typical flow rate).
The flue gas desulfurization maximum design chlorides (for
the flue gas desulfurization system) in parts per million (ppm) and
operating chlorides (in the flue gas desulfurization purge/slurry) in
ppm.
Where a plant is taking any steps to minimize the amount of flue
gas desulfurization scrubber purge (or slurry discharge) sent to
treatment or discharge, the EPA solicits comment describing the
processes utilized, or considered, to minimize flow. For example,
several stakeholders have suggested that replacement of water-based
seals with mechanical seals has been evaluated or conducted at a number
of facilities.
CRL Flow Rates at New Waste Management Units
Since the effective date of the 2015 CCR rule, many facilities have
constructed new landfills, landfill cells, and surface impoundments
with composite (or alternative composite) liners. Since these liners
and associated leachate-collection systems may differ from pre-2015
practices, the EPA solicits comment on CRL flow rate information from
these new waste management units. Specifically, to ensure that the EPA
can compare, and potentially replace, data collected as part of the
2010 survey, for each waste management unit constructed post-2015 the
Agency solicits comment on the following updated information:
A description of the leachate-collection system.
The typical and maximum gallons per day volume of leachate
(including leaks, seepage, toe drains, or similar releases) collected
in 2024 and 2025.
The frequency of process wastewater generation in 2024 and
2025 (days per year).
A description of the estimation method where not directly
measured.
A description of how the collected leachate is managed
(e.g., transferred to an on-site treatment system, commingled and
treated with flue gas desulfurization wastewater, rerouted back to the
impoundment).
The EPA also solicits comment on any waste management units which
have closed since the 2010 survey where collected CRL flows at these
waste management units now differ from the 2010 survey data, including
where such waste management units have clean closed and no longer
generate CRL.
Pilot Tests
Utilities and vendors have described the limitations in
423.13(g)(3) and 423.15(b)(13) as unnecessarily tight, requiring
additional pre-treatment or post-treatment from the treatment chain
described in prior rulemakings. The EPA solicits comment providing
pilot testing data on FGDFGD wastewater and CRL that would suggest a
relaxation of these limitations might be warranted when applied to
discharges from existing sources. Specifically, the EPA solicits
comment providing draft or final pilot studies (whether on-site or off-
site), including any influent and effluent data and associated
laboratory reports. While the existing limitations utilize indicator
pollutants, the EPA solicits comment providing information on any
relevant pollutants so that the Agency might consider whether similar
removals are attainable with less treatment across a range of such
pollutants.
XIII. Statutory and Executive Order Reviews
Additional information about these statutes and Executive Orders
can be found at https://www.epa.gov/laws-regulations/laws-and-executive-orders.
A. Executive Order 12866: Regulatory Planning and Review and Executive
Order 13563: Improving Regulation and Regulatory Review
This proposed action is an economically significant regulatory
action as defined under section 3(f)(1) of Executive Order 12866.
Accordingly, it was submitted to the Office of Management and Budget
(OMB) for review. Any changes made in response to E.O. 12866
interagency review have been documented in the docket. The potential
impacts of this rule are summarized in section VII of this preamble.
This analysis, ``Economic Analysis Memorandum for the Effluent
Limitations Guidelines and Standards for the Steam Electric Power
Generating Point Source Category--Unmanaged Combustion Residual
Leachate'' (DCN SE12127), is available in the docket. From a 2024 ELG
baseline, the EPA estimated that the proposed action would result in
annualized cost savings of $446 million and $1,090 million in 2024
dollars at a three percent discount rate, for the lower and upper bound
cost scenarios, respectively. Similarly, the EPA estimated that the
proposed action would save $532 million and $1,286 million annually (in
2024 dollars), for the lower and upper bound cost scenarios,
respectively, at a seven percent discount rate.
B. Executive Order 14192: Unleashing Prosperity Through Deregulation
This action is expected to be an Executive Order 14192 deregulatory
action, based on the preferred option, Option 1.
C. Paperwork Reduction Act (PRA)
This action does not impose any new information collection burden
under the PRA. OMB has previously approved the information collection
activities contained in the existing regulations under OMB control
number 2040-0313.
D. Regulatory Flexibility Act (RFA)
I certify that this action will not have a significant economic
impact on a substantial number of small entities under the RFA. In
making this determination, the EPA concludes that the impact of concern
for this rule is any significant adverse economic impact on small
entities and that the agency is certifying that this rule will not have
a significant economic impact on a substantial number of small entities
because the rule relieves regulatory burden on the small entities
subject to the rule. Of the estimated 111 to 191 small entities that
own steam electric plants subject to these ELGs, the EPA estimated that
two small entities (one cooperative and one nonutility) will incur
unmanaged CRL compliance costs equal to or greater than one percent of
revenue and the same two entities' compliance costs also exceed three
percent of revenue.
This proposed rule does not cause adverse impacts on small
entities. In fact, Option 1, the preferred option, is estimated to
result in fewer small entities incurring significant impacts. Between 5
and 11 fewer small entities will experience impacts exceeding one
percent of revenue as a direct result of this rule if finalized, and
between 4 and 6 fewer small entities will experience
[[Page 28513]]
impacts exceeding three percent of revenue.
Therefore, relative to baseline, the proposed rule significantly
reduces the burden on small entities compared to the baseline where an
estimated seven to 13 small entities incur unmanaged CRL costs equal to
or greater than one percent of revenue. The EPA detailed its analysis
in the Economic Analysis memo in the record (DCN SE12127). I have
therefore concluded that this action will not impose a regulatory
burden on any regulated small entities while relieving burden on
between 7 and 13 small entities.
E. Unfunded Mandates Reform Act (UMRA)
This proposed action does not contain an unfunded mandate as
described in UMRA, 2 U.S.C. 1531-1538, and does not significantly or
uniquely affect small governments. The proposed action imposes no
enforceable duty on any State, local or Tribal governments or the
private sector.
F. Executive Order 13132: Federalism
This action does not have federalism implications. It will not have
substantial direct effects on the States, on the relationship between
the national government and the States, or on the distribution of power
and responsibilities among the various levels of government.
G. Executive Order 13175: Consultation and Coordination With Indian
Tribal Governments
This proposed action would not have Tribal implications as
specified in Executive Order 13175. It does not have substantial direct
effects on Tribal governments, on the relationship between the Federal
Government and the Indian Tribes, or the distribution of power and
responsibilities between the Federal Government and Indian Tribes as
specified in Executive Order 13175. The EPA's analyses show that no
plant subject to the proposed ELGs is owned by Tribal governments.
Thus, Executive Order 13175 does not apply to this action.
H. Executive Order 13045: Protection of Children From Environmental
Health Risks and Safety Risks
The EPA interprets Executive Order 13045 as applying only to those
regulatory actions that concern environmental health or safety risks
that the EPA has reason to believe may disproportionately affect
children, per the definition of ``covered regulatory action'' in
section 2-202 of the Executive Order. Therefore, this proposed action
is not subject to Executive Order 13045. Since any health effects of
this proposed action would not fall disproportionally on children, the
EPA's Policy on Children's Health also does not apply.
I. Executive Order 13211: Actions Concerning Regulations That
Significantly Affect Energy Supply, Distribution, or Use
This proposed action is not a ``significant energy action'' because
it is not likely to have a significant adverse effect on the supply,
distribution or use of energy. The proposed rule is estimated to reduce
costs to the industry. The annualized cost savings are small relative
to the estimated total electricity generation across the power sector
(equivalent to 0.01 to 0.03 cents per kWh).
J. National Technology Transfer and Advancement Act (NTTAA)
This rulemaking does not involve technical standards.
List of Subjects in 40 CFR Part 423
Environmental protection, Electric power generation, Power
facilities, Waste treatment and disposal, Water pollution control.
Lee Zeldin,
Administrator.
For the reasons stated in the preamble, the Environmental
Protection Agency proposes to amend 40 CFR part 423 as follows:
PART 423--STEAM ELECTRIC POWER GENERATING POINT SOURCE CATEGORY
0
1. The authority citation for part 423 continues to read as follows:
Authority: 33 U.S.C. 1251 et seq.; 1311; 1314(b), (c), (e),
(g), and (i)(A) and (B); 1316; 1317; 1318 and 1361.
0
2. Amend Sec. 423.11 by adding paragraph (gg) to read as follows:
Sec. 423.11 Specialized definitions
* * * * *
(gg) The term closed coal combustion residual waste management unit
means a landfill or surface impoundment which does not receive coal
combustion residuals on or after July 8, 2024. Removal of coal
combustion residuals from the waste management unit does not affect
that unit's closure status under this part. Any closed coal combustion
residual waste management unit that receives coal combustion residuals
is no longer defined as closed under this part.
0
3. Amend Sec. 423.13 by:
0
a. Revising paragraphs (l)(1)(i) and (l)(2)(ii);
0
b. Redesignating paragraph (l)(2)(iii) as (l)(2)(iv);
0
c. Adding a new paragraph (l)(2)(iii);
0
d. Removing the table heading ``Table 12 to Paragraph (l)(2)(iii)'' and
adding in its place ``Table 12 to Paragraph (l)(2)(iv)''; and
0
e. Adding paragraph (l)(3).
The revisions and additions read as follows:
Sec. 423.13 Effluent limitations guidelines representing the degree
of effluent reduction attainable by the application of the best
available technology economically achievable (BAT).
* * * * *
(l) * * *
(1) * * *
(i) Except for those discharges to which paragraph (l)(1)(i)(B) or
(C) or (l)(2) of this section applies, there shall be no discharge of
pollutants in combustion residual leachate.
* * * * *
(2) * * *
(ii) For discharges of unmanaged combustion residual leachate as
defined at Sec. 423.11(ff)(2), the quantity of pollutants in unmanaged
combustion residual leachate shall not exceed the quantity determined
by multiplying the flow of unmanaged combustion residual leachate times
the concentration in table 11 to paragraph (l)(2)(i)(A) of this
section.
(A) Dischargers must meet the effluent limitations for unmanaged
combustion residual leachate in this paragraph (l)(2)(ii) by a date
determined by the permitting authority that is as soon as possible
beginning July 8, 2024, but no later than December 31, 2034. The
effluent limitations in this paragraph (l)(2)(ii) apply to the
discharge of unmanaged combustion residual leachate generated on and
after the date determined by the permitting authority for meeting the
effluent limitations, as specified in this paragraph (l)(2)(ii).
(B) For discharges of unmanaged combustion residual leachate before
the date determined in paragraph (l)(2)(ii)(A) of this section, the EPA
is declining to establish BAT limitations and is reserving such
limitations to be established by the permitting authority on a case-by-
case basis using the permitting authority's best professional judgment.
(iii) For discharges of unmanaged combustion residual leachate as
defined at Sec. 423.11(ff)(1), site-specific BAT effluent limitations
shall be established by the permitting authority after reviewing the
information in paragraph (l)(2)(iii)(A). The site-specific BAT
[[Page 28514]]
effluent limitations must reflect the permitting authority's
determination of the maximum warranted reduction in pollutant
discharges after consideration of factors relevant for determining the
best available technology at each facility.
(A) To determine the site-specific BAT effluent limitations, the
permitting authority shall consider:
(1) the annual leachate monitoring report and data collected under
Sec. 423.19(k);
(2) groundwater monitoring, corrective action, closure plans, and
reports conducted under the Coal Combustion Residuals Disposal
Regulations at 40 CFR part 257 subpart D including the magnitude of
residual contaminant mass, if any, that may remain in groundwater
following implementation of a required remedy;
(3) other readily available groundwater monitoring data upstream
and downstream of each impoundment or landfill owned or operated by the
facility, including the relevant state's department of water quality
monitoring data and characterization of background groundwater quality
that has not been affected by leakage from a disposal of Coal
Combustion Residuals unit as defined in 40 CFR 257.53;
(4) results of any modeling of leachate fate and transport
conducted for the facility; and,
(5) whether the facility is already complying with the numeric
limitations for mercury and arsenic for unmanaged combustion residual
leachate where that leachate has been captured and pumped to the
surface for discharge directly to a waters of the United States.
(6) The permitting authority may consider impacts of site-specific
BAT effluent limitations that result in unacceptable changes in local
energy demand, energy costs to consumers, solid waste generation, air
pollution, and fuel consumption.
(7) The permitting authority may consider pending must-run orders
that a utility remain in operation longer than planned.
(B) The permitting authority must provide a written explanation of
the site-specific best available technology determination in the fact
sheet or statement of basis for the draft permit under 40 CFR 124.7 or
124.8. The written explanation must describe why the permitting
authority has rejected any technologies or measures that perform better
than the selected technologies or measures.
(C) The site-specific best available technology put forth in the
fact sheet or statement of basis may include consideration of any
additional information deemed appropriate by the permitting authority
including the statutory factors listed in the Clean Water Act section
304(b). The weight given to each factor is within the permitting
authority's discretion based upon the circumstances of each facility.
(D) The permitting authority may require additional information or
monitoring from the permit applicant to support the site-specific
determination of best available technology, including an inspection.
(E) Prior to any permit reissuance after December 31, 2031, the
permitting authority must review the monitoring results and other
performance measures of the facility to determine whether it continues
to meet the requirements of paragraphs (l)(1) and (2) of this section.
* * * * *
(3) Facilities permanently ceasing combustion of coal.
(i) Paragraphs (l)(1) and (2) of this section do not apply to
combustion residual leachate generated by electric generating units at
facilities that meet the applicability at Sec. 423.10(a) as of July 8,
2024, but where the facility has permanently ceased generation of
electricity from a process utilizing fossil type fuel. Instead, BAT
effluent limitations for combustion residual leachate shall be
established by the permitting authority on a case-by-case basis using
best professional judgment.
(ii) Paragraphs (l)(1) and (2) of this section do not apply to
combustion residual leachate generated by a closed coal combustion
residual waste management unit as defined at Sec. 423.11(gg). Instead,
BAT effluent limitations for combustion residual leachate shall be
established by the permitting authority on a case-by-case basis using
best professional judgment.
* * * * *
[FR Doc. 2026-09895 Filed 5-15-26; 8:45 am]
BILLING CODE 6560-50-P