Document ID: EPA-HQ-OW-2009-0819-7106
Agency: epa
Document Type: Proposed Rule
Title: Effluent Limitations Guidelines and Standards for the Steam Electric Power Generating Point Source Category
Posted Date: 2019-11-22T05:00Z

[Federal Register Volume 84, Number 226 (Friday, November 22, 2019)]
[Proposed Rules]
[Pages 64620-64677]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2019-24686]

[[Page 64619]]

Vol. 84

Friday,

No. 226

November 22, 2019

Part II

 Environmental Protection Agency

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40 CFR Part 423

Effluent Limitations Guidelines and Standards for the Steam Electric 
Power Generating Point Source Category; Proposed Rule

  Federal Register / Vol. 84 , No. 226 / Friday, November 22, 2019 / 
Proposed Rules  

[[Page 64620]]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 423

[EPA-HQ-OW-2009-0819; FRL-10002-04-OW]
RIN 2040-AF77

Effluent Limitations Guidelines and Standards for the Steam 
Electric Power Generating Point Source Category

AGENCY: Environmental Protection Agency.

ACTION: Proposed rule.

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SUMMARY: The Environmental Protection Agency (the EPA or the Agency) is 
proposing a regulation to revise the technology-based effluent 
limitations guidelines and standards (ELGs) for the steam electric 
power generating point source category applicable to flue gas 
desulfurization (FGD) wastewater and bottom ash (BA) transport water. 
This proposal is estimated to save approximately $175 million dollars 
annually in pre-tax compliance costs and $137 million dollars annually 
in social costs as a result of less costly FGD wastewater technologies 
that could be used with the proposed relaxation of the Steam Electric 
Power Generating Effluent Guidelines 2015 rule (the 2015 rule) selenium 
limitation; less costly BA transport water technologies made possible 
by the proposed relaxation of the 2015 rule's zero discharge 
limitations; a two-year extension of compliance timeframes for meeting 
FGD wastewater limits, and additional proposed subcategories for both 
FGD wastewater and BA transport water. EPA also believes that 
participation in the voluntary incentive program would further reduce 
the pollutants that these steam electric facilities discharge in FGD 
wastewater by approximately 105 million pounds per year.

DATES: 
    Comments. Comments on this proposed rule must be received on or 
before January 21, 2020.
    Public Hearing. The EPA will conduct an online public hearing about 
today's proposed rule on December 19, 2019. Following a brief 
presentation by EPA personnel, the Agency will accept oral comments 
that will be limited to three (3) minutes per commenter. The hearing 
will be recorded and transcribed, and the EPA will consider all of the 
oral comments provided, along with the written public comments 
submitted via the docket for this rulemaking. To register for the 
hearing, please visit the EPA's website at https://www.epa.gov/eg/steam-electric-power-generating-effluent-guidelines-2019-proposed-revisions.

ADDRESSES: Submit your comments on the proposed rule, identified by 
Docket No. EPA-HQ-OW-2009-0819, by one of the following methods:
     Federal eRulemaking Portal: https://www.regulations.gov/ 
(preferred method). Follow the online instructions for submitting 
comments.
     Email: a-and-r-docket@epa.gov. Include Docket ID No. EPA-
HQ-OW-2009-0819 (specify the applicable docket number) in the subject 
line of the message.
     Fax: (202) 566-9744. Attention Docket ID No. EPA-HQ-OW-
2009-0819 (specify the applicable docket number).
     Mail: U.S. Environmental Protection Agency, EPA Docket 
Center, Docket ID No. EPA-HQ-OW-2009-0819, Office of Science and 
Technology Docket, Mail Code 28221T, 1200 Pennsylvania Avenue NW, 
Washington, DC 20460.
     Hand Delivery/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.-4:30 p.m., 
Monday-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 any 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: For technical information, contact 
Richard Benware, Engineering and Analysis Division, Telephone: 202-566-
1369; Email: benware.richard@epa.gov. For economic information, contact 
James Covington, Engineering and Analysis Division, Telephone: 202-566-
1034; Email: covington.james@epa.gov.

SUPPLEMENTARY INFORMATION:
    Preamble Acronyms and Abbreviations. We use multiple acronyms and 
terms in this preamble. While this list may not be exhaustive, to ease 
the reading of this preamble and for reference purposes, the EPA 
defines terms and acronyms used in Appendix A.
    Supporting Documentation. The rule proposed today is supported by a 
number of documents including:
     Supplemental Technical Development Document for Proposed 
Revisions to the Effluent Limitations Guidelines and Standards for the 
Steam Electric Power Generating Point Source Category (Supplemental 
TDD), Document No. EPA-821-R-19-009. This report summarizes the 
technical and engineering analyses supporting the proposed rule. The 
Supplemental TDD presents the EPA's updated analyses supporting the 
proposed revisions to FGD wastewater and BA transport water. These 
updates include additional data collection that has occurred since the 
publication of the 2015 rule, updates to the industry (e.g., 
retirements, updates to FGD treatment and BA handling), cost 
methodologies, pollutant removal estimates, corresponding nonwater 
quality environmental impacts associated with updated FGD and BA 
methodologies, and calculation of the proposed effluent limitations. 
Except for the updates described in the Supplemental TDD, the Technical 
Development Document for the Effluent Limitations Guidelines and 
Standards for the Steam Electric Power Generating Point Source Category 
(2015 TDD, Document No. EPA-821-R-15-007) is still applicable and 
provides a more complete summary the EPA's data collection, description 
of the industry, and underlying analyses supporting the 2015 rule.
     Supplemental Environmental Assessment for Proposed 
Revisions to the Effluent Limitations Guidelines and Standards for the 
Steam Electric Power Generating Point Source Category (Supplemental 
EA), Document No. EPA-821-R-19-010. This report summarizes the 
potential environmental and human health impacts that are estimated to 
result from implementation of the proposed revisions to the 2015 rule.
     Benefit and Cost Analysis for Proposed Revisions to the 
Effluent Limitations Guidelines and Standards for the Steam Electric 
Power Generating Point Source Category (BCA Report), Document No. EPA-
821-R-19-011. This report summarizes estimated societal benefits and 
costs that are estimated to result from implementation of the proposed 
revisions to the 2015 rule.
     Regulatory Impact Analysis for Proposed Revisions to the 
Effluent Limitations Guidelines and Standards for the Steam Electric 
Power Generating Point Source Category (RIA), Document No. EPA-821-R-
19-012. This report presents a profile of the steam electric power 
generating industry, a summary of estimated costs and impacts 
associated with the proposed revisions to the 2015 rule, and an 
assessment of

[[Page 64621]]

the potential impacts on employment and small businesses.
     Docket Index for the Proposed Revisions to the Steam 
Electric ELGs. This document provides a list of the additional 
memoranda, references, and other information relied upon by the EPA for 
the proposed revisions to the ELGs.
    Organization of this Document. The information in this preamble is 
organized as follows:

I. Executive Summary
II. Public Participation
III. General Information
    A. Does this action apply to me?
    B. What action is the Agency Taking?
    C. What is the Agency's authority for taking this action?
    D. What are the monetized incremental costs and benefits of this 
action?
IV. Background
    A. Clean Water Act
    B. Relevant Effluent Guidelines
    1. Best Practicable Control Technology Currently Available (BPT)
    2. Best Available Technology Economically Achievable (BAT)
    3. Pretreatment Standards for Existing Sources (PSES)
    C. 2015 Rule
    D. Legal Challenges, Administrative Petitions, Section 705 
Action, Postponement Rule, and Reconsideration of Certain 
Limitations and Standards
    E. Other Ongoing Rules Impacting the Steam Electric Sector
    1. Clean Power Plan (CPP) and Affordable Clean Energy (ACE)
    2. Coal Combustion Residuals (CCR)
    F. Scope of This Proposed Rulemaking
V. Steam Electric Power Generating Industry Description
    A. General Description of Industry
    B. Current Market Conditions in the Electricity Generation 
Sector
    C. Control and Treatment Technologies
    1. FGD Wastewater
    2. BA Transport Water
VI. Data Collection Since the 2015 Rule
    A. Information From the Electric Utility Industry
    1. Engineering Site Visits
    2. Data Requests, Responses, and Meetings
    3. Voluntary BA Transport Water Sampling
    4. Electric Power Research Institute (EPRI) Voluntary Submission
    5. Meetings With Trade Associations
    B. Information From the Drinking Water Utility Industry and 
States
    C. Information From Technology Vendors and Engineering, 
Procurement, and Construction (EPC) Firms
    D. Other Data Sources
VII. Proposed Regulation
    A. Description of the BAT/PSES Options
    1. FGD Wastewater
    2. BA Transport Water
    B. Rationale for the Proposed BAT
    1. FGD Wastewater
    2. BA Transport Water
    3. Rationale for Voluntary Incentives Program (VIP)
    C. Additional Proposed Subcategories
    1. Subcategory for Facilities With High FGD Flows
    2. Subcategory for Boilers With Low Utilization
    3. Subcategory for Boilers Retiring by 2028
    D. Availability Timing of New Requirements
    E. Regulatory Sub-Options To Address Bromides
    F. Economic Achievability
    G. Non-Water Quality Environmental Impacts
    H. Impacts on Residential Electricity Prices and Low-Income and 
Minority Populations
    I. Additional Rationale for the Proposed PSES
VIII. Costs, Economic Achievability, and Other Economic Impacts
    A. Facility-Specific and Industry Total Costs
    B. Social Costs
    C. Economic Impacts
    1. Screening-Level Assessment
    a. Facility-Level Cost-to-Revenue Analysis
    b. Parent Entity-Level Cost-to-Revenue Analysis
    2. Electricity Market Impacts
    a. Impacts on Existing Steam Electric Facilities
    b. Impacts on Individual Facilities Incurring Costs
IX. Changes to Pollutant Loadings
    A. FGD Wastewater
    B. BA Transport Water
    C. Summary of Incremental Changes of Pollutant Loadings From 
Proposed Regulatory Options
X. Non-Water Quality Environmental Impacts
    A. Energy Requirements
    B. Air Pollution
    C. Solid Waste Generation and Beneficial Use
    D. Changes in Water Use
XI. Environmental Assessment
    A. Introduction
    B. Updates to the Environmental Assessment Methodology
    C. Outputs From the Environmental Assessment
XII. Benefits Analysis
    A. Categories of Benefits Analyzed
    B. Quantification and Monetization of Benefits
    1. Changes in Human Health Benefits From Changes in Surface 
Water Quality
    2. Changes in Surface Water Quality
    3. Effects on Threatened and Endangered Species
    4. Changes in Benefits From Marketing of Coal Combustion 
Residuals
    5. Changes in Dredging Costs
    6. Changes in Air-Related Effects
    7. Benefits From Changes in Water Withdrawals
    C. Total Monetized Benefits
    D. Unmonetized Benefits
XIII. Development of Effluent Limitations and Standards
    A. FGD Wastewater
    1. Overview of the Limitations and Standards
    2. Criteria Used To Select Data
    3. Data Used To Calculate Limitations and Standards
    4. Long-Term Averages and Effluent Limitations and Standards for 
FGD Wastewater
    B. BA Transport Water Limitations
    1. Maximum 10 Percent 30-Day Rolling Average Purge Rate
    2. Best Management Practices Plan
XIV. Regulatory Implementation
    A. Implementation of the Limitations and Standards
    1. Timing
    2. Implementation for the Low Utilization Subcategory
    a. Determining Boiler Net Generation
    b. Tiering Limitations
    3. Addressing Withdrawn or Delayed Retirement
    a. Involuntary Retirement Delays
    b. Voluntary Retirement Withdrawals and Delays
    B. Reporting and Recordkeeping Requirements
    C. Site-Specific Water Quality-Based Effluent Limitations
XV. Related Acts of Congress, Executive Orders, and Agency 
Initiatives
    A. Executive Orders 12866 (Regulatory Planning and Review) and 
13563 (Improving Regulation and Regulatory Review)
    B. Executive Order 13771 (Reducing Regulation and Controlling 
Regulatory Costs)
    C. Paperwork Reduction Act
    D. Regulatory Flexibility Act
    E. Unfunded Mandates Reform Act
    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 That Significantly Affect 
Energy Supply, Distribution, or Use
    J. National Technology Transfer and Advancement Act
    K. Executive Order 12898: Federal Actions To Address 
Environmental Justice in Minority Populations and Low-Income 
Populations
    L. Congressional Review Act (CRA)
Appendix A to the Preamble: Definitions, Acronyms, and Abbreviations 
Used in This Preamble

I. Executive Summary

A. Purpose of Rule

    Coal-fired facilities are impacted by several environmental 
regulations. One of these regulations, the Steam Electric Power 
Generating ELGs was promulgated in 2015 (80 FR 67838; November 3, 2015) 
and applies to the subset of the electric power industry where 
``generation of electricity is the predominant source of revenue or 
principal reason for operation, and whose generation of electricity 
results primarily from a process utilizing fossil-type fuel (coal, oil, 
gas), fuel derived from fossil fuel (e.g., petroleum coke, synthesis 
gas), or nuclear fuel in

[[Page 64622]]

conjunction with a thermal cycle employing the steam-water system as 
the thermodynamic medium.'' (40 CFR 423.10). The 2015 rule addressed 
discharges from flue gas desulfurization (FGD) wastewater, fly ash 
transport water, bottom ash transport water, flue gas mercury control 
wastewater, gasification wastewater, combustion residual leachate, and 
non-chemical metal cleaning wastes.
    In the few years since the steam electric ELGs were revised in 
2015, steam electric facilities have installed more affordable 
technologies which are capable of removing a similar amount of 
pollution as those which existed in 2015. This proposal would revise 
requirements for two of the waste streams addressed in the 2015 rule: 
Bottom ash (BA) transport water and flue gas desulfurization (FGD) 
wastewater--two of the facilities' largest sources of wastewater--while 
reducing industry costs as compared to the costs of the 2015 rule's 
controls. This proposal does not seek to revise the other waste streams 
covered by the 2015 rule.

B. Summary of Proposed Rule

    For existing sources that discharge directly to surface water, with 
the exception of the subcategories discussed below, the proposed rule 
would establish the following effluent limitations based on Best 
Available Technology Economically Achievable (BAT):
     For flue gas desulfurization wastewater, there are two 
sets of proposed BAT limitations. The first set of limitations is a 
numeric effluent limitation on Total Suspended Solids (TSS) in the 
discharge of FGD wastewater. The second set of BAT limitations 
comprises numeric effluent limitations on mercury, arsenic, selenium, 
and nitrate/nitrite as nitrogen in the discharge of FGD wastewater.
     For bottom ash transport water, there are two sets of 
proposed BAT limitations. The first set of BAT limitations is a numeric 
effluent limitation on TSS in the discharge of these wastewaters. The 
second set of BAT limitations is a not-too-exceed 10 percent volumetric 
purge limitation.
    The proposed rule includes separate requirements for the following 
subcategories: High flow facilities, low utilization boilers, and 
boilers retiring by 2028. The proposed rule does not seek to change the 
existing subcategories for oil-fired boilers and small generating units 
(50 MW or less) from the 2015 rule. For high flow facilities (FGD 
wastewater flows over four million gallons per day after accounting for 
that facility's ability to recycle the wastewater to the maximum limits 
for the FGD system materials of construction) or low utilization 
boilers (876,000 MWh per year or less), the proposed rule would 
establish the second set of BAT limitations in the discharge of FGD 
wastewater as numeric effluent limitations only on mercury and arsenic 
(and not on selenium and nitrate/nitrite as nitrogen). For low 
utilization boilers, the proposed rule would establish BAT limitations 
for BA transport water for TSS, and would also include standards for 
implementation of a best management practices (BMP) plan. For oil-fired 
boilers, small boilers (50 MW or less), and boilers retiring by 2028, 
the proposed rule would establish BAT limitations for TSS in FGD 
wastewater and bottom ash transport water.
    The proposed rule would establish a voluntary incentives program 
that provides the certainty of more time (until December 31, 2028) for 
facilities to implement new standards and limitations, if they adopt 
additional process changes and controls that achieve more stringent 
limitations on mercury, arsenic, selenium, nitrate/nitrite, bromide, 
and total dissolved solids in FGD wastewater. The optional program 
offers environmental protections beyond those achieved by the proposed 
BAT limitations, while providing facilities that opt into the program 
more flexibility (such as additional time) than the current voluntary 
incentives program.
    For indirect discharges (i.e., discharges to publicly owned 
treatment works), the proposed rule establishes pretreatment standards 
for existing sources that are the same as the BAT limitations, except 
for TSS, where there is no pass through of pollutants at POTWs.
    Where BAT limitations in this rule are more stringent than 
previously established BPT limitations, the EPA proposes that those 
limitations do not apply until a date determined by the permitting 
authority that is as soon as possible on or after November 1, 2020, but 
that is no later than December 31, 2023 (for BA transport water) or 
December 31, 2025 (for FGD wastewater).

C. Summary of Costs and Benefits

    The EPA has estimated costs and benefits of four different 
regulatory options. The EPA estimates that its proposed option (i.e., 
Option 2) will save $136.3 million per year in social costs and result 
in between $14.8 million and $68.5 million in benefits, using a three 
percent discount, and will save $166.2 million per year in social costs 
and between $28.4 million and $74.4 million in benefits, using a seven 
percent discount. Table XV-1 summarizes the benefits and social costs 
for the four regulatory options at a three percent discount rates. The 
EPA's analysis reflects the Agency's understanding of the actions steam 
electric facilities will take to meet the limitations and standards in 
the final rule. The EPA based its analysis on a baseline that reflects 
the expected impacts of announced retirements and fuel conversions, 
impacts of relevant rules such as the Coal Combustion Residuals (CCR) 
rule that the Agency promulgated in April 2015 and the Affordable Clean 
Energy Rule (ACE) that the Agency promulgated in 2019, and the full 
implementation of the 2015 rule. The EPA understands that these modeled 
results have uncertainty and that the actual costs could be higher or 
lower than estimated. The current estimate reflects the best data and 
analysis available at this time. For additional information, see 
Sections V and VIII.

II. Public Participation

    Submit your comments, identified by Docket ID No. EPA-HQ-OW-2009-
0819, at https://www.regulations.gov (our preferred method), or the 
other methods identified in the ADDRESSES section. Once submitted, 
comments cannot be edited or removed from the docket. The EPA may 
publish any comment received to its public docket. Do not submit 
electronically any information you consider to be Confidential Business 
Information (CBI) or other information whose disclosure is restricted 
by statute. Multimedia submissions (audio, video, etc.) must be 
accompanied by a written comment. The written comment is considered the 
official comment and should include discussion of all points you wish 
to make. The EPA will generally not consider comments or comment 
contents located outside of the primary submission (i.e., on the web, 
cloud, or other file sharing system). For additional submission 
methods, the full EPA public comment policy, information about CBI or 
multimedia submissions, and general guidance on making effective 
comments, please visit https://www.epa.gov/dockets/commenting-epa-dockets.

III. General Information

A. Does this action apply to me?

    Entities potentially regulated by any final rule following this 
action include:

[[Page 64623]]

------------------------------------------------------------------------
                                                 North American Industry
        Category          Example of regulated    Classification System
                                 entity                (NAICS) code
------------------------------------------------------------------------
Industry...............  Electric Power                            22111
                          Generation
                          Facilities--Electric
                          Power Generation.
                         Electric Power                           221112
                          Generation
                          Facilities--Fossil
                          Fuel Electric Power
                          Generation.
------------------------------------------------------------------------

    This section is not intended to be exhaustive, but rather provides 
a guide regarding entities likely to be regulated by any final rule 
following this action. Other types of entities that do not meet the 
above criteria could also be regulated. To determine whether your 
facility is regulated by any final rule following this action, you 
should carefully examine the applicability criteria listed in 40 CFR 
423.10 and the definitions in 40 CFR 423.11 of the 2015 rule. If you 
still have questions regarding the applicability of any final rule 
following this action to a particular entity, consult the person listed 
for technical information in the preceding FOR FURTHER INFORMATION 
CONTACT section.

B. What action is the Agency taking?

    The agency is proposing to revise certain Best Available Technology 
Economically Achievable (BAT) effluent limitations guidelines and 
pretreatment standards for existing sources in the steam electric power 
generating point source category that apply to FGD wastewater and BA 
transport water.

C. What is the Agency's authority for taking this action?

    The EPA is proposing to promulgate this rule under the authority of 
sections 301, 304, 306, 307, 308, 402, and 501 of the Clean Water Act 
(CWA), 33 U.S.C. 1311, 1314, 1316, 1317, 1318, 1342, and 1361.

D. What are the monetized incremental costs and benefits of this 
action?

    This action is estimated to save $136.3 million per year in social 
costs and result in between $14.8 million and $68.5 million in 
benefits, using a 3 percent discount rate. Using a 7 percent discount 
rate, the estimated savings are $166.2 million per year and benefits 
are between $28.4 million and $74.4 million.

IV. Background

A. Clean Water Act

    Among its core provisions, the CWA prohibits the discharge of 
pollutants from a point source to waters of the U.S., except as 
authorized under the CWA. Under section 402 of the CWA, 33 U.S.C. 1342, 
discharges may be authorized through a National Pollutant Discharge 
Elimination System (NPDES) permit. The CWA establishes a dual approach 
for these permits: (1) Technology-based controls that establish a floor 
of performance for all dischargers, and (2) water quality-based 
effluent limitations, where the technology-based effluent limitations 
are insufficient to meet applicable water quality standards (WQS). As 
the basis for the technology-based controls, the CWA authorizes the EPA 
to establish national technology-based effluent limitations guidelines 
and new source performance standards for discharges into waters of the 
United States from categories of point sources (such as industrial, 
commercial, and public sources).
    The CWA also authorizes the EPA to promulgate nationally applicable 
pretreatment standards that control pollutant discharges from sources 
that discharge wastewater indirectly to waters of the U.S., through 
sewers flowing to POTWs, as outlined in sections 307(b) and (c) of the 
CWA, 33 U.S.C. 1317(b) and (c). The EPA establishes national 
pretreatment standards for those pollutants in wastewater from indirect 
dischargers that pass through, interfere with, or are otherwise 
incompatible with POTW operations. Pretreatment standards are designed 
to ensure that wastewaters from direct and indirect industrial 
dischargers are subject to similar levels of treatment. See CWA section 
301(b), 33 U.S.C. 1311(b). In addition, POTWs are required to implement 
local treatment limitations applicable to their industrial indirect 
dischargers to satisfy any local requirements. See 40 CFR 403.5.
    Direct dischargers (those discharging to waters of the U.S. rather 
than to a POTW) must comply with effluent limitations in NPDES permits. 
Indirect dischargers, who discharge through POTWs, must comply with 
pretreatment standards. Technology-based effluent limitations and 
standards in NPDES permits are derived from effluent limitations 
guidelines (CWA sections 301 and 304, 33 U.S.C. 1311 and 1314) and new 
source performance standards (CWA section 306, 33 U.S.C. 1316) 
promulgated by the EPA, or are based on best professional judgment 
(BPJ) where EPA has not promulgated an applicable effluent limitation 
guideline or new source performance standard (CWA section 402(a)(1)(B), 
33 U.S.C. 1342(a)(1)(B)). Additional limitations are also required in 
the permit where necessary to meet WQS. CWA section 301(b)(1)(C), 33 
U.S.C. 1311(b)(1)(C). The ELGs are established by EPA regulation for 
categories of industrial dischargers and are based on the degree of 
control that can be achieved using various levels of pollution control 
technology, as specified in the Act (e.g., BPT, BCT, BAT; see below).
    EPA promulgates national ELGs for industrial categories for three 
classes of pollutants: (1) Conventional pollutants (total suspended 
solids (TSS), oil and grease, biochemical oxygen demand (BOD5), fecal 
coliform, and pH), as outlined in CWA section 304(a)(4), 33 U.S.C. 
1314(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), 33 U.S.C. 1317(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 (TDS)).

B. Relevant Effluent Guidelines

    The EPA establishes ELGs based on the performance of well-designed 
and well-operated control and treatment technologies. The legislative 
history also supports that the EPA need not consider water quality 
impacts on individual water bodies as the guidelines are developed; see 
Statement of Senator Muskie (principal author) (October 4, 1972), 
reprinted in Legislative History of the Water Pollution Control Act 
Amendments of 1972, at 170. (U.S. Senate, Committee on Public Works, 
Serial No. 93-1, January 1973).
    There are four types of standards applicable to direct dischargers 
and two types of standards applicable to indirect dischargers. The 
three standards relevant to this rulemaking are described in detail 
below.

[[Page 64624]]

1. Best Practicable Control Technology Currently Available (BPT)
    Traditionally, the EPA establishes effluent limitations based on 
BPT by reference to the average of the best performances of facilities 
within the industry, grouped to reflect various ages, sizes, processes, 
or other common characteristics. The EPA promulgates BPT effluent 
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 (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). If, however, existing 
performance is uniformly inadequate, the EPA may establish limitations 
based on higher levels of control than those currently in place in an 
industrial category, when based on an Agency determination that the 
technology is available in another category or subcategory and can be 
practically applied.
2. Best Available Technology Economically Achievable (BAT)
    BAT represents the second level of control for direct discharges of 
toxic and nonconventional pollutants. As the statutory phrase intends, 
the EPA considers the technological availability and the 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 must consider in assessing BAT are the cost of achieving 
BAT effluent reductions, the age of equipment and facilities involved, 
the process employed, potential process changes, non-water quality 
environmental impacts (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); Texas Oil & Gas Ass'n v. EPA, 
161 F.3d 923, 928 (5th Cir. 1998). The Agency retains considerable 
discretion in assigning the weight to be accorded each of these 
required consideration factors. Weyerhaeuser Co. v. Costle, 590 F.2d 
1011, 1045 (D.C. Cir. 1978). Generally, the EPA determines economic 
achievability based on the effect of the cost of compliance with BAT 
limitations on overall industry and subcategory (if applicable) 
financial conditions. BAT is intended to reflect the highest 
performance in the industry, and it may reflect a higher level of 
performance than is currently being achieved based on technology 
transferred from a different subcategory or category, bench scale or 
pilot studies, or foreign facilities. 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). BAT may be based upon process changes 
or internal controls, even when these technologies are not common 
industry practice. See Am. Frozen Food Inst., 539 F.2d 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 (2nd Cir. 1977).
    One way that EPA may take into account differences within an 
industry when establishing BAT limitations is through 
subcategorization. The Supreme Court has recognized that the 
substantive test for subcategorizing an industry is the same as that 
which applies to establishing fundamentally different factor 
variances--i.e., whether the plants are different with respect to 
relevant statutory factors. See Chem. Mfrs. Ass'n v. EPA, 870 F.2d 177, 
214 n.134 (5th Cir. 1989) (citing Chem. Mfrs. Ass'n v. NRDC, 470 U.S. 
116, 119-22, 129-34 (1985)). Courts have stated that there need only be 
a rough basis for subcategorization. See Chem. Mfrs. Ass'n v. EPA, 870 
F.2d at 215 n.137 (summarizing cases).
3. Pretreatment Standards for Existing Sources (PSES)
    Section 307(b) of the CWA, 33 U.S.C. 1317(b), authorizes the EPA to 
promulgate pretreatment standards for discharges of pollutants to 
POTWs. PSES are designed to prevent the discharge of pollutants that 
pass through, interfere with, or are otherwise incompatible with the 
operation of POTWs. Categorical pretreatment standards are technology-
based and are analogous to BPT and BAT effluent limitations guidelines, 
and thus the Agency typically considers the same factors in 
promulgating PSES as it considers in promulgating BPT and BAT. 
Legislative history indicates that Congress intended for the 
combination of pretreatment and treatment by the POTW to achieve the 
level of treatment that would be required if the industrial source were 
discharging to a water of the U.S. Conf. Rep. No. 95-830, at 87 (1977), 
reprinted in U.S. Congress. Senate Committee on Public Works (1978), A 
Legislative History of the CWA of 1977, Serial No. 95-14 at 271 (1978). 
The General Pretreatment Regulations, which set forth the framework for 
the implementation of categorical pretreatment standards, are found at 
40 CFR 403. These regulations establish pretreatment standards that 
apply to all non-domestic dischargers. See 52 FR 1586 (January 14, 
1987).

C. 2015 Rule

    The EPA, on September 30, 2015, finalized a rule revising the 
regulations for the Steam Electric Power Generating point source 
category (40 CFR part 423) (hereinafter the ``2015 rule''). The rule 
set the first federal limitations on the levels of toxic metals in 
wastewater that can be discharged from steam electric facilities, based 
on technology improvements in the steam electric power industry over 
the preceding three decades. Prior to the 2015 rule, regulations for 
the industry had been last updated in 1982.
    New technologies for generating electric power and the widespread 
implementation of air pollution controls over the last 30 years have 
altered existing wastewater streams or created new wastewater streams 
at many steam electric facilities, particularly coal-fired facilities. 
Discharges of these wastestreams include arsenic, lead, mercury, 
selenium, chromium, and cadmium. Many of these toxic pollutants, once 
in the environment, remain there for years, and continue to cause 
impacts.
    The 2015 rule addressed effluent limitations and standards for 
multiple wastestreams generated by new and existing steam electric 
facilities: BA transport water, combustion residual leachate, FGD 
wastewater, flue gas mercury control wastewater, fly ash (FA) transport 
water, and gasification wastewater. The rule required most steam 
electric facilities to comply with the effluent limitations ``as soon 
as possible'' after November 1, 2018, and no later than December 31, 
2023. Within that range, except for indirect dischargers, the 
particular compliance date(s) for each facility would be determined by 
the facility's National Pollutant Discharge Elimination System permit, 
which is typically issued by a state environmental agency.
    On an annual basis, the 2015 rule was projected to reduce the 
amount of metals defined in the Act as toxic pollutants, nutrients, and 
other pollutants that steam electric facilities are allowed to 
discharge by 1.4 billion pounds and reduce water withdrawal by 57 
billion gallons. At the time, the EPA estimated annual compliance costs 
for the final rule to be $480 million (in 2013

[[Page 64625]]

dollars) and estimated benefits associated with the rule to be $451 to 
$566 million (in 2013 dollars).

D. Legal Challenges, Administrative Petitions, Section 705 Action, 
Postponement Rule, and Reconsideration of Certain Limitations and 
Standards

    Seven petitions for review of the 2015 rule were filed in various 
circuit courts by the electric utility industry, environmental groups, 
and drinking water utilities. These petitions were consolidated in the 
U.S. Court of Appeals for the Fifth Circuit, Southwestern Electric 
Power Co., et al. v. EPA.\1\ On March 24, 2017, the Utility Water Act 
Group (UWAG) submitted to the EPA an administrative petition for 
reconsideration of the 2015 rule. Also, on April 5, 2017, the Small 
Business Administration (SBA) submitted an administrative petition for 
reconsideration of the final rule.
---------------------------------------------------------------------------

    \1\ Case No. 15-60821.
---------------------------------------------------------------------------

    On April 25, 2017, the EPA responded to these petitions by 
publishing a postponement of the 2015 rule compliance deadlines that 
had not yet passed, under Section 705 of the Administrative Procedure 
Act (APA). This Section 705 Action drew multiple legal challenges.\2\ 
The Administrator then signed a letter on August 11, 2017, announcing 
his decision to conduct a rulemaking to potentially revise the new, 
more stringent BAT effluent limitations and pretreatment standards for 
existing sources in the 2015 rule that apply to FGD wastewater and BA 
transport water. The Fifth Circuit subsequently granted EPA's request 
to sever and hold in abeyance aspects of the litigation related to 
those limitations and standards. With respect to the remaining claims 
related to limitations applicable to legacy wastewater and leachate, 
which are not at issue in this proposed rulemaking, the Fifth Circuit 
issued a decision on April 12, 2019, vacating those limitations as 
arbitrary and capricious under the Administrative Procedure Act and 
unlawful under the CWA, respectively. The EPA plans to address this 
vacatur in a subsequent action.
---------------------------------------------------------------------------

    \2\ See Clean Water Action. v. EPA, No. 17-0817 (D.D.C.), appeal 
docketed, No. 18-5149 (D.C. Cir.); see also Clean Water Action. v. 
EPA, No. 18-60619 (5th Cir.) (case dismissed for lack of 
jurisdiction on October 18, 2018).
---------------------------------------------------------------------------

    In September 2017, the EPA finalized a rule, using notice-and-
comment procedures, postponing the earliest compliance dates for the 
new, more stringent BAT effluent limitations and PSES for FGD 
wastewater and BA transport water in the 2015 rule, from November 1, 
2018 to November 1, 2020. The EPA also withdrew its prior action taken 
pursuant to Section 705 of the APA. The rule received multiple legal 
challenges, but EPA prevailed, and the courts did not sustain any of 
them.\3\
---------------------------------------------------------------------------

    \3\ See Center for Biological Diversity v. EPA, No. 18-cv-00050 
(D. Ariz. filed Jan. 20, 2018); see also Clean Water Action. v. EPA, 
No. 18-60079 (5th Cir.). On October 29, 2018, the District of 
Arizona case was dismissed upon EPA's motion to dismiss for lack of 
jurisdiction, and on August 28, 2019, the Fifth Circuit denied the 
petition for review of the postponement rule.
---------------------------------------------------------------------------

E. Other Ongoing Rules Impacting the Steam Electric Sector

1. Clean Power Plan (CPP) and Affordable Clean Energy (ACE)
    The final 2015 CPP established carbon dioxide (CO2) 
emission guidelines for fossil-fuel fired facilities based in part on 
shifting generation at the fleet-wide level from one type of energy 
source to another. On February 9, 2016, the U.S. Supreme Court stayed 
implementation of the CPP pending judicial review. West Virginia v. 
EPA, No. 15A773 (S.Ct. Feb. 9, 2016).
    On June 19, 2019, the EPA issued the ACE rule, an effort to provide 
existing coal-fired electric utility generating units (EGUs) with 
achievable and realistic standards for reducing greenhouse gas 
emissions. This action was finalized in conjunction with two related, 
but separate and distinct rulemakings: (1) The repeal of the CPP, and 
(2) revised implementing regulations for ACE, ongoing emission 
guidelines, and all future emission guidelines for existing sources 
issued under the authority of Clean Air Act section 111(d). ACE 
provides states with new emission guidelines that will inform the 
state's development of standards of performance to reduce 
CO2 emissions from existing coal-fired EGUs consistent with 
the EPA's role as defined in the CAA.
    ACE establishes heat rate improvement (HRI), or efficiency 
improvement, as the best system of emissions reduction (BSER) for 
CO2 from coal-fired EGUs.\4\ By employing a broad range of 
HRI technologies and techniques, EGUs can more efficiently generate 
electricity with less carbon intensity.\5\ The BSER is the best 
technology or other measure that has been adequately demonstrated to 
improve emissions performance for a specific industry or process (a 
``source category''). In determining the BSER, the EPA considers 
technical feasibility, cost, non-air quality health and environmental 
impacts, and energy requirements. The BSER must be applicable to, at, 
and on the premises of an affected facility. ACE lists six HRI 
``candidate technologies,'' as well as additional operating and 
maintenance (O&M) practices.\6\ For each candidate technology, the EPA 
has provided information regarding the degree of emission limitation 
achievable through application of the BSER as ranges of expected 
improvement and costs.
---------------------------------------------------------------------------

    \4\ Heat rate is a measure of the amount of energy required to 
generate a unit of electricity.
    \5\ An improvement to heat rate results in a reduction in the 
emission rate of an EGU (in terms of CO2 emissions per 
unit of electricity produced).
    \6\ These six technologies are: (1) Neural Network/Intelligent 
Sootblowers, (2) Boiler Feed Pumps, (3) Air Heater and Duct Leakage 
Control, (4) Variable Frequency Drives, (5) Blade Path Upgrade 
(Steam Turbine), and (6) Redesign/Replace Economizer.
---------------------------------------------------------------------------

    The 2015 rule analyses incorporated compliance costs associated 
with the 2015 CPP, resulting in, among other things, baseline 
retirements associated with that rule in the Integrated Planning Model 
(IPM). As noted in the ACE RIA, while the final repeal of the CPP has 
been promulgated, the business-as-usual economic conditions achieved 
the carbon reductions laid out in the final CPP. The EPA used the IPM 
version 6 to analyze today's proposal to be consistent with the base 
case analyses done for the ACE final rule. The Agency also performed a 
sensitivity analysis on the proposed Option 2, following promulgation 
of the ACE final rule, that estimates the impacts of the proposed 
option relative to a baseline that includes the ACE rule. A similar 
sensitivity analysis was not conducted for Option 4. The EPA intends to 
perform IPM runs with the most up-to-date version of the model 
available for the final rule. See additional discussion of IPM in 
Section VIII of this preamble.
2. Coal Combustion Residuals (CCR)
    On April 17, 2015, the Agency published the Disposal of Coal 
Combustion Residuals from Electric Utilities final rule. This rule 
finalized national regulations to provide a comprehensive set of 
requirements for the safe disposal of CCRs, commonly known as coal ash, 
from coal-fired facilities. The final CCR rule was the culmination of 
extensive study on the effects of coal ash on the environment and 
public health. The 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.
    These regulations addressed coal ash disposal, including 
regulations designed to prevent leaking of contaminants into ground 
water, blowing of contaminants into the air as dust, and the 
catastrophic failure of coal ash surface

[[Page 64626]]

impoundments. Additionally, the CCR rule set out recordkeeping and 
reporting requirements as well as the requirement for each facility to 
establish and post specific information to a publicly-accessible 
website. This final CCR rule also supported the responsible recycling 
of CCRs by distinguishing safe, beneficial use from disposal.
    As explained in the 2015 rule, the ELGs and CCR rules may affect 
the same boiler or activity at a facility. That being the case, when 
the EPA finalized both rules in 2015, the Agency coordinated them to 
facilitate and minimize the complexity of implementing engineering, 
financial, and permitting activities. The coordination of the two rules 
continues to be a consideration in the development of today's proposal. 
The EPA's analysis of this proposal incorporates the same approach used 
in the 2015 rule to estimate how the CCR rule may affect surface 
impoundments and the ash handling systems and FGD treatment systems 
that send wastes to those impoundments. However, as a result of the 
D.C. Circuit Court rulings in USWAG v. EPA, No. 15-1219 (D.C. Cir. 
2018) and Waterkeeper Alliance Inc, et al. v. EPA, No. 18-1289 (D.C. 
Cir. 2019), amendments to the CCR rule are being proposed which would 
establish a deadline of August 2020 by which all unlined surface 
impoundments \7\ must cease receiving waste, subject to certain 
exceptions. This would not impact the ability of facilities to install 
new, composite lined surface impoundments. This CCR proposal and 
accompanying background documents are available at www.regulations.gov 
Docket EPA-HQ-OLEM-2019-0172, and comments on that proposal should be 
submitted to that docket.
---------------------------------------------------------------------------

    \7\ Due to the Court vacatur of 40 CFR part 257.71(a)(1)(i) 
(provision for clay-lined surface impoundments) clay-lined surface 
impoundments are currently also considered unlined.
---------------------------------------------------------------------------

    In order to account for the CCR rule proposed amendments in this 
proposed rule, the EPA conducted a sensitivity analysis to determine 
how the closure of unlined surfaced impoundments would impact the 
compliance cost and pollutant loading estimates for today's proposal. 
After conducting this sensitivity analysis, the EPA found that the 
capital and operation and maintenance compliance cost estimates 
decrease by 50 to 60 percent and the total industry pollutant loadings 
decrease by five percent (see DCN SE07233).
    The EPA solicits comment on the overlap between these two rules, 
including whether the Agency's cost benefit and regulatory impact 
analyses appropriately capture the overlap of the two rules, and ways 
that the Agency could harmonize the timelines for regulatory 
requirements. The Agency also solicits comment on the extent to which 
facilities have chosen to construct new composite lined surface 
impoundments for the treatment of bottom ash transport water or FGD 
wastewater. Comments on the intersection of the two rules should be 
submitted to both dockets.

F. Scope of This Proposed Rulemaking

    This proposal, if finalized, would revise the new, more stringent 
BAT effluent limitations guidelines and pretreatment standards for 
existing sources in the 2015 rule that apply to FGD wastewater and BA 
transport water. It does not propose otherwise to amend (nor is the EPA 
requesting comment on) the effluent limitations guidelines and 
standards for other wastes discharged by the steam electric power 
generating point source category. The EPA plans to address the Court's 
remand in Southwestern Elec. Power Co. v. EPA with respect to the 
limitations for leachate and legacy wastewater in a subsequent action.

V. Steam Electric Power Generating Industry Description

A. General Description of Industry

    The EPA provided a general description of the steam electric power 
generating industry in the 2013 proposed rule and the 2015 rule, and 
has continued to collect information and update that profile. The 
previous descriptions reflected the known information about the 
universe of steam electric facilities and incorporated applicable final 
environmental regulations at that time. For this proposal, as described 
in the Supplemental TDD Section 3, the EPA has revised its description 
of the steam electric power generating industry (and its supporting 
analyses) to incorporate major changes such as additional retirements, 
fuel conversions, ash handling conversions, wastewater treatment 
updates, and updated information on capacity utilization.\8\ The 
analyses supporting this proposal use an updated baseline that 
incorporates these changes in the industry. The analyses then compare 
the effect of today's proposed rules for FGD wastewater and bottom ash 
transport water to the effect of the 2015 rule's limitations for FGD 
wastewater and BA transport water on the industry as it exists today.
---------------------------------------------------------------------------

    \8\ The data presented in the general description continues to 
rely on some 2009 conditions, as the industry survey remains the 
EPA's best available source of information for characterizing 
operations across the industry.
---------------------------------------------------------------------------

B. Current Market Conditions in the Electricity Generation Sector

    Market conditions in the electricity generation sector have changed 
significantly and rapidly in the past decade. These changes include 
availability of abundant and inexpensive natural gas, emergence of 
alternative fuel technologies, and continued aging of coal-fired 
facilities. These changes have resulted in coal-fired unit and facility 
retirements and switching of fuels. The lower cost of natural gas and 
technological advances in solar and wind power have had a depressive 
effect on both coal-fired and nuclear-powered generation. (This 
proposal, if finalized, would have no effect on the nuclear-powered 
sector, except as it might affect relative prices through its impacts 
on coal-fired generation.) In the coal-fired sector, the market forces 
are manifest as scaling back coal-fired power generation (including 
unit and facility closures) at an accelerated rate. The rate of coal 
capacity retirement is affected by regulation affecting coal-fired 
electricity generation as there have been regulations adopted, 
particularly in the last decade (e.g., CCR, CPP and 2015 Steam Electric 
ELG), that are cited by some power companies when they announce unit or 
facility closures, fuel switching, or other operational changes. Among 
some utilities, there is also a general trend of supplementing or 
replacing traditional generation with alternative sources. As these 
changes happen in the industry, the electric power infrastructure 
adjusts and generally trends toward the optimal infrastructure and 
operations that deliver the country's power demand, with negative 
effects for some communities and positive effects for others. The 
negative distributional effects can be particularly difficult for 
communities affected by company decisions to scale back or retire a 
facility. Also see Section 2.3 of the RIA.

C. Control and Treatment Technologies

    In general, control and treatment technologies for some 
wastestreams have continued to advance since the 2015 rule. Often, 
these advancements provide facilities with additional ways of meeting 
effluent limitations, in some instances at a lower cost. For this 
proposal, the EPA incorporated updated information and evaluated 
several technologies available to control and treat FGD wastewater and 
BA transport water produced by the steam electric

[[Page 64627]]

power generating industry. See Section VIII of this preamble for 
details on updated cost information.
1. FGD Wastewater
    FGD scrubber systems, either dry or wet, are used to remove sulfur 
dioxide from flue gas so that sulfur dioxide is not emitted into the 
air. Dry FGD systems generally do not discharge wastewater, as the 
water they use is evaporated during operation; wet FGD systems do 
produce a wastewater stream.
    As part of this proposed rule, the EPA is including two additional 
FGD wastewater treatment technologies among the suite of regulatory 
options that were not evaluated as main regulatory options in the 2015 
rule: Low Hydraulic Residence Time Biological Reduction (LRTR) and 
membrane filtration, which are further described below.
     LRTR System. A biological treatment system that targets 
removal of selenium and nitrate/nitrite using fixed-film bioreactors in 
smaller, more compact reaction vessels than those used in the 
biological treatment system evaluated in the 2015 rule (referred to in 
this proposal as HRTR--high residence time biological reduction). The 
LRTR system is designed to operate with a shorter residence time (on 
the order of 1 to 4 hours, as compared to a residence time of 10-16 
hours for HRTR), while still achieving significant removal of selenium 
and nitrate/nitrite. The LRTR technology option considered as part of 
this proposed rule includes chemical precipitation as a pretreatment 
stage prior to the bioreactor and ultrafiltration as a polishing step 
following the bioreactor.
     Membrane Filtration. A membrane filtration system designed 
specifically for high TDS and TSS wastestreams. These systems are 
designed to eliminate fouling and scaling associated with industrial 
wastewater. These systems typically combine pretreatment for potential 
scaling agents such as calcium, magnesium, and sulfates, and one or 
more types of membrane technology (e.g., nanofiltration, or reverse 
osmosis) to remove a broad array of particulate and dissolved 
pollutants from FGD 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.
    Steam electric facilities discharging FGD wastewater currently 
employ a variety of wastewater treatment technologies and operating/
management practices to reduce the pollutants associated with FGD 
wastewater discharges. As part of the 2015 rule, the EPA identified the 
following types of treatment and handling practices for FGD wastewater:
     Chemical precipitation systems that use tanks to treat FGD 
wastewater. Chemicals are added to help remove suspended solids and 
dissolved solids, particularly metals. The precipitated solids are then 
removed from solution by coagulation/flocculation, followed by 
clarification and/or filtration. The 2015 rule focused on a specific 
design that employs hydroxide precipitation, sulfide precipitation 
(organosulfide), and iron coprecipitation to remove suspended solids 
and to convert soluble metal ions to insoluble metal hydroxides or 
sulfides.
     Biological treatment systems that use microorganisms to 
treat FGD wastewater. The EPA identified three types of biological 
treatment systems used to treat FGD wastewater: (1) Anoxic/anaerobic 
fixed-film bioreactors, which target removals of nitrogen compounds and 
selenium, as well as other metals; (2) anoxic/anaerobic suspended 
growth systems, which target removals of selenium and other metals; and 
(3) aerobic/anaerobic sequencing batch reactors, which target removals 
of organics and nutrients. The 2015 rule focused on a specific design 
of anoxic/anaerobic fixed-film bioreactors that employs a relatively 
long residence time for the microbial processes. The bioreactor design 
used as the basis for the 2015 rule, with typical hydraulic residence 
time on the order of approximately 10 to 16 hours, is referred to in 
this rulemaking as high residence time reduction (HRTR). The BAT 
technology basis for the 2015 rule also included chemical precipitation 
as a pretreatment stage prior to the bioreactor and a sand filter as a 
polishing step following the bioreactor (i.e., CP+HRTR).
     Thermal evaporation systems that 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 the volume of wastewater by 80 to 90 percent and also 
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 facility or discharged. These systems are designed to 
remove the broad spectrum of pollutants present in FGD wastewater to 
very low effluent concentrations.
     Constructed wetland systems using natural biological 
processes involving wetland vegetation, soils, and microbial activity 
to reduce the concentrations of metals, nutrients, and TSS in 
wastewater. High temperature, chemical oxygen demand (COD), nitrates, 
sulfates, boron, and chlorides in the wastewater can adversely affect 
constructed wetlands' performance. To avoid this, facilities typically 
find it necessary to dilute the FGD wastewater with service water 
before it enters the wetland.
     Some facilities operate their wet FGD systems using 
approaches that eliminate the discharge of FGD wastewater. These 
facilities use a variety of operating and management practices to 
achieve this.

--Complete recycle. Facilities that operate in this manner do not 
produce a saleable solid product from the FGD system (e.g., wallboard-
grade gypsum). Because the facilities are not selling the FGD gypsum, 
they are able to allow the landfilled material to contain elevated 
levels of chlorides, and as a result do not need a separate wastewater 
purge stream.
--Evaporation impoundments. Some facilities in warm, dry climates have 
been able to use surface impoundments as holding basins from which the 
FGD wastewater evaporates. The evaporation rate from the impoundments 
at these facilities is greater than or equal to the flow rate of the 
FGD wastewater and amount of precipitation entering the impoundments; 
therefore, there is no discharge to surface water.
--Fly ash (FA) conditioning. Many facilities that operate dry FA 
handling systems will add water to the FA to suppress dust or improve 
handling and/or compaction characteristics in an on-site landfill. The 
EPA is not aware of any plants using FGD wastewater to condition ash 
that will be marketed.
--Combination of wet and dry FGD systems. The dry FGD process involves 
atomizing and injecting wet lime slurry, which ranges from 
approximately 18 to 25 percent solids, into a spray dryer. The water in 
the slurry evaporates from the heat of the flue gas within the system, 
leaving a dry residue that is removed from the flue gas by a fabric 
filter (i.e., a baghouse) or electrostatic precipitator (ESP).
--Underground injection. These systems dispose of wastes by injecting 
them into an underground well as an alternative to discharging 
wastewater to surface waters.

    The EPA also collected new information on other FGD wastewater 
treatment technologies, including spray

[[Page 64628]]

dryer evaporators, direct contact thermal evaporators, zero valent iron 
treatment, forward osmosis, absorption or adsorption media, ion 
exchange, electrocoagulation, and electrodialysis reversal. These 
treatment technologies have been evaluated at fullscale or pilotscale, 
or are being developed to treat FGD wastewater. See Section 4.1 of the 
Supplemental TDD for more information on these technologies.
2. BA Transport Water
    BA consists of heavier ash particles that are not entrained in the 
flue gas and fall to the bottom of the furnace. In most furnaces, the 
hot BA is quenched in a water-filled hopper.\9\ Many facilities use 
water to transport (sluice) the BA from the hopper to an impoundment 
system or a dewatering bin system. In both the impoundment and 
dewatering bin systems, the BA transport water is usually discharged to 
surface water as overflow from the system, after the BA has settled to 
the bottom. In addition to wet sluicing to an impoundment or dewatering 
bin system, the industry also uses the following BA handling systems 
that generate BA transport water:
---------------------------------------------------------------------------

    \9\ Consistent with the 2015 rule, boiler slag is considered BA.
---------------------------------------------------------------------------

     Remote Mechanical Drag System. These systems use the same 
processes as wet-sluicing impoundment or dewatering bin systems to 
transport bottom ash to a remote mechanical drag system. A drag chain 
conveyor dewaters the bottom ash by pulling it out of the water bath on 
an incline. The system can either be operated as a closed-loop 
(evaluated during the 2015 rule) or a high recycle rate system. For 
this proposed rule, under the high recycle rate option, facilities 
would be permitted to purge a portion of the wastewater from the system 
to maintain a high recycle rate, as described in Section VII of this 
preamble.\10\
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    \10\ In some cases, additional treatment may be necessary to 
maintain a closed-loop system. This additional treatment could 
include polymer addition to enhance removal of suspended solids, or 
membrane filtration of a slip stream to remove dissolved solids.
---------------------------------------------------------------------------

     Dense Slurry System. These systems use a dry vacuum or 
pressure system to convey the bottom ash to a silo (as described below 
for the ``Dry Vacuum or Pressure System''), but instead of using trucks 
to transport the bottom ash to a landfill, the facility mixes the 
bottom ash with water (a lower percentage of water compared to a wet-
sluicing system) and pumps the mixture to the landfill.
    As part of the 2015 rule and this reconsideration, the EPA 
identified the following BA handling systems that do not generate 
bottom ash transport water.
     Mechanical Drag System. These systems are located directly 
underneath the boiler. The bottom ash is collected in a water quench 
bath. A drag chain conveyor dewaters the bottom ash by pulling it out 
of the water bath on an incline.
     Dry Mechanical Conveyor. These systems are located 
directly underneath the boiler. The system uses ambient air to cool the 
bottom ash in the boiler and then transports the ash out of the boiler 
on a conveyor. No water is used in this process.
     Dry Vacuum or Pressure System. These systems transport 
bottom ash from the boiler to a dry hopper without using any water. Air 
is percolated through the ash to cool it and combust unburned carbon. 
Cooled ash then drops to a crusher and is conveyed via vacuum or 
pressure to an intermediate storage destination.
     Vibratory Belt System. These systems deposit bottom ash 
into a vibratory conveyor trough, where the ash is air-cooled and 
ultimately moved through the conveyor deck to an intermediate storage 
destination without using any water.
     Submerged Grind Conveyor. These systems are located 
directly underneath the boiler and are designed to reuse slag tanks, 
ash gates, clinker grinders, and transfer enclosures from the existing 
wet sluicing systems. The system collects bottom ash from the discharge 
of each clinker grinder. A series of submerged drag chain conveyors 
transport and dewater the bottom ash.
    See Section 4.2 of the Supplemental TDD for more information on 
these technologies.

VI. Data Collection Since the 2015 Rule

A. Information From the Electric Utility Industry

1. Engineering Site Visits
    During October and November 2017, the EPA conducted seven site 
visits to facilities in five states. The EPA selected facilities to 
visit using information gathered in support of the 2015 rule, 
information from industry outreach, and publicly available facility-
specific information. The EPA visited four facilities that were 
previously visited in support of the 2015 rule because they had 
recently conducted, or were currently conducting, FGD wastewater 
treatment pilot studies. The EPA also revisited facilities that had 
implemented new FGD wastewater treatment technologies or BA handling 
systems (after the 2015 rule) to learn more about implementation 
timing, start-up and operation, and implementation costs.
    The specific objectives of these site visits were to gather general 
information about each facility's operations; their pollution 
prevention and wastewater treatment system operations; their ongoing 
pilot or laboratory scale studies for FGD wastewater treatment; and BA 
handling system conversions.
2. Data Requests, Responses, and Meetings
    Under the authority of Section 308 of the Clean Water Act (CWA) (33 
U.S.C. 1318), in January 2018, the EPA requested the following 
information from nine steam electric power companies that own coal-
fired facilities generating FGD wastewater:
     FGD wastewater characterization data associated with 
testing and implementation of treatment technologies, in 2013 or later.
     Information on halogen usage to reduce flue gas emissions, 
as well as halogen concentration data in FGD wastewater.
     Projected installations of FGD wastewater treatment 
technologies.
     Cost information for projected or installed FGD wastewater 
treatment systems, from bids received in 2013 or later.
    After receiving each company's response, the EPA met with these 
companies to discuss the FGD-related data submitted, other FGD and BA 
data outside the scope of the request that the company believed to be 
relevant, and suggestions each company had for potential changes to the 
2015 rule with respect to FGD wastewater and BA transport water. The 
EPA used this information to learn more about the performance of 
treatment systems, inform the development of FGD wastewater 
limitations, learn more about facility-specific halogen usage (such as 
bromide), and obtain information useful for updating cost estimates of 
installing candidate treatment technologies. As needed, the EPA 
conducted follow-up meetings and conference calls with industry 
representatives to discuss and clarify these data.
3. Voluntary BA Transport Water Sampling
    In December 2017, the EPA invited seven steam electric facilities 
to participate in a voluntary BA transport water sampling program 
designed to obtain data to supplement the wastewater characterization 
data set for BA transport water included in the record for the 2015 
rule. The EPA asked facilities to provide analytical data for

[[Page 64629]]

ash pond effluent and untreated BA transport water (i.e., ash pond 
influent). The EPA selected the facilities based on their responses to 
its 2010 Questionnaire for the Steam Electric Power Generating Effluent 
Guidelines (see Section 3.2 of the 2015 TDD). Two facilities chose to 
participate in the voluntary BA sampling program. These data were 
incorporated into the analytical data set used to estimate pollutant 
removals for BA transport water.
4. Electric Power Research Institute (EPRI) Voluntary Submission
    EPRI conducts studies--funded by the steam electric power 
generating industry--to evaluate and demonstrate technologies that can 
potentially remove pollutants from wastestreams or eliminate 
wastestreams using zero discharge technologies. Following the 2015 
rule, the EPA reviewed 35 reports published between 2011 and 2018 that 
EPRI voluntarily provided regarding characteristics of FGD wastewater 
and BA transport water, FGD wastewater treatment pilot studies, BA 
handling practices, halogen addition rates, and the effect of halogen 
additives on FGD wastewater. The EPA used information presented in 
these reports to inform the development of numeric effluent limitations 
for FGD wastewater and to update methods for estimating the costs and 
pollutant removals associated with candidate treatment technologies.
5. Meetings With Trade Associations
    In May and June of 2018, the EPA met with the Edison Electric 
Institute (EEI), the National Rural Electric Cooperatives Association 
(NRECA), and the American Public Power Association (APPA). These trade 
associations represent investor-owned utilities, electric cooperatives, 
and community-owned utilities, respectively. The EPA also met with the 
Utility Water Act Group (UWAG), an association comprising the trade 
associations above as well as individual electric utilities. The EPA 
met with each of these trade associations separately and together to 
discuss the technologies and the analyses presented in the 2015 rule 
and to hear suggestions for potential changes to the 2015 rule. The EPA 
also used information from these meetings to update industry profile 
data (i.e., accounting for retirements, fuel conversions, and updated 
treatment technology installations).

B. Information From the Drinking Water Utility Industry and States

    The EPA obtained additional information from the drinking water 
utility sector and states on the effects of bromide discharges from 
steam electric facilities on drinking water treatment processes. First, 
the EPA received letters from, and met with, the American Water Works 
Association (AWWA), the Association of Metropolitan Water Agencies 
(AMWA), the National Association of Water Companies (NAWC), the 
Association of Clean Water Administrators (ACWA), and the Association 
of State Drinking Water Administrators (ASDWA). Second, the EPA visited 
two drinking water treatment facilities in North Carolina that have 
modified their treatment processes to address an increase in 
disinfection byproduct levels due to bromide discharges from an 
upstream steam electric power facility. Finally, the EPA obtained data 
on surface water bromide concentrations and data from drinking water 
monitoring from the two drinking water treatment facilities. The EPA 
also obtained existing state data from other drinking water treatment 
facilities from the states of North Carolina and Virginia.

C. Information From Technology Vendors and Engineering, Procurement, 
and Construction (EPC) Firms

    The EPA gathered data on availability and effectiveness from 
technology vendors and EPC firms through presentations, conferences, 
meetings, and email and phone contacts regarding FGD wastewater and BA 
handling technologies used in the industry. The data collected informed 
the development of the technology costs and pollutant removal estimates 
for FGD wastewater and BA transport water. The EPC firms also suggested 
potential changes to the 2015 rule.

D. Other Data Sources

    The EPA gathered information on steam electric generating 
facilities from the Department of Energy's (DOE's) Energy Information 
Administration (EIA) Forms EIA-860 (Annual Electric Generator Report) 
and EIA-923 (Power Plant Operations Report). The EPA used the 2015 
through 2017 data to update the industry profile prepared for the 2015 
rule, including commissioning dates, energy sources, capacity, net 
generation, operating statuses, planned retirement dates, ownership, 
and pollution controls of the boilers.
    The EPA conducted literature and internet searches to gather 
information on FGD wastewater treatment technologies, including 
information on pilot studies, applications in the steam electric power 
generating industry, and implementation costs and timelines. The EPA 
also used the internet searches to identify or confirm reports of 
planned facility and boiler retirements, and reports of planned unit 
conversions to dry or closed-loop recycle ash handling systems. The EPA 
used this information to inform the industry profile and identify 
process modifications occurring in the industry.
    The EPA received information from several environmental groups and 
other stakeholders following the 2015 rule. In general, these groups 
voiced concerns about extending the period that facilities could 
continue to discharge FGD wastewater and BA transport water pollutants 
subject to BPT limitations, as well as steam electric bromide 
discharges, their interaction with drinking water treatment facilities, 
and the associated human health effects. They also noted the improved 
availability of technological controls for reducing or eliminating 
pollutant discharges from FGD and BA handling systems. Finally, they 
provided examples where they believed that states had not properly 
considered the ``as soon as possible date'' for the new, more stringent 
BAT requirements in the 2015 rule when issuing permits.

VII. Proposed Regulation

A. Description of the BAT/PSES Options

    The proposal evaluates four regulatory options and identifies one 
proposed option, as shown in Table VII-1. All options include similar 
technology bases for BA transport water, except that Option 2 allows 
surface impoundments and a BMP plan for low utilization boilers. In 
general, each successive option from Option 1 to 4 would achieve a 
greater reduction in FGD wastewater pollutant discharges. Each 
subcategorization is described further in Section VII.C below. 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 EPA relied upon to 
develop the proposed regulatory options, as well as the proposed BAT, 
effluent limitations, and alternate approaches included in this 
proposal.

[[Page 64630]]

                                                          Table VII-1--Main Regulatory Options
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                Technology basis for the BAT/PSES  regulatory options
            Wastestream                    Subcategory      --------------------------------------------------------------------------------------------
                                                                        1                      2                      3                      4
--------------------------------------------------------------------------------------------------------------------------------------------------------
FGD Wastewater.....................  N/A...................  Chemical precipitation  Chemical               Chemical               Membrane filtration.
                                                                                      precipitation + low    precipitation + low
                                                                                      hydraulic residence    hydraulic residence
                                                                                      time biological        time biological
                                                                                      treatment.             treatment.
                                     High FGD flow           NS....................  Chemical               Chemical               Chemical
                                      facilities.                                     precipitation.         precipitation.         precipitation.
                                     Low utilization         NS....................  Chemical               NS...................  NS.
                                      boilers.                                        precipitation.
                                     Boilers retiring by     Surface impoundments..  Surface impoundments.  Surface impoundments.  Surface impoundments.
                                      2028.
--------------------------------------------------------------------------------------------------------------------------------------------------------
FGD Wastewater Voluntary Incentives Program (Direct          Membrane filtration...  Membrane filtration..  Membrane filtration..  N/A.
 Dischargers Only).
--------------------------------------------------------------------------------------------------------------------------------------------------------
BA Transport Water.................  N/A...................  Dry handling or High    Dry handling or High   Dry handling or High   Dry handling or High
                                                              recycle rate systems.   recycle rate systems.  recycle rate systems.  recycle rate
                                                                                                                                    systems.
                                     Low utilization         NS....................  Surface impoundments   NS...................  NS.
                                      boilers.                                        +BMP plan.
                                     Boilers retiring by     Surface impoundments..  Surface impoundments.  Surface impoundments.  Surface impoundments.
                                      2028.
--------------------------------------------------------------------------------------------------------------------------------------------------------
NS = Not Subcategorized.
Note: The table above does not present existing subcategories included in the 2015 rule as the EPA is not proposing any changes to the existing
  subcategorization of oil-fired units or units with a nameplate capacity of 50 MW or less.

1. FGD Wastewater
    Under Option 1, the EPA would establish BAT limitations and PSES 
for mercury and arsenic based on chemical precipitation. For Options 2 
and 3, the EPA would establish BAT limitations and PSES for mercury, 
arsenic, selenium, and nitrate/nitrate based on chemical precipitation 
followed by LRTR and ultrafiltration. Option 2 subcategorizes boilers 
producing less than 876,000 MWh per year \11\ and for those boilers 
would require mercury and arsenic limitations and pretreatment 
standards based on chemical precipitation.\12\ Finally, for Option 4, 
the EPA would establish BAT limitations and PSES for mercury, arsenic, 
selenium, nitrate-nitrite, bromide, and TDS based on membrane 
filtration. Options 2, 3, and 4 would subcategorize facilities with 
high FGD flows, and for this subcategory would establish limitations 
and standards for mercury and arsenic based on chemical precipitation. 
Under all four options, boilers retiring by December 31, 2028, would be 
subcategorized, and for this subcategory BAT limitations would be set 
equal to BPT limitations for TSS based on the use of surface 
impoundments. Finally, the EPA would establish voluntary incentives 
program limitations for mercury, arsenic, selenium, nitrate-nitrite, 
bromide, and TDS based on membranes.
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    \11\ The equivalent of a 100 MW boiler operating at 100% 
capacity or a 400 MW boiler operating at 25% capacity.
    \12\ As explained above, EPA is not proposing to revise BAT 
limitations or PSES for oil-fired boilers and/or small boilers (50 
MW or smaller).
---------------------------------------------------------------------------

2. BA Transport Water
    Under all options described above, the EPA proposes to control 
discharge of pollutants from BA transport water by establishing daily 
BAT limitations and PSES on the volume of BA transport water that can 
be discharged based on high recycle rate systems. A high recycle rate 
system is a recirculating wet ash handling system operated such that it 
periodically discharges (purges) a small portion of the process 
wastewater from the system. Under all options, boilers retiring by 
December 31, 2028, would be subcategorized, and for this subcategory, 
BAT limitations would be set equal to BPT limitations for TSS, based on 
gravity settling in surface impoundments. Under Option 2, for boilers 
producing less than 876,000 MWh per year, BAT effluent limitations for 
BA transport water would be set equal to the BPT effluent limitations 
based on gravity settling in surface impoundments to remove TSS.\13\ 
Such facilities would also be required to develop and implement a BMP 
plan to minimize the discharge of pollutants from BA transport water. 
Because POTWs are designed to treat conventional pollutants such as 
TSS, TSS is not considered to pass through and EPA would establish PSES 
based on the inclusion of a BMP plan only. For additional information 
on pass through analysis, see Section VII(C) of the 2015 rule preamble. 
Finally, the EPA proposes a slight modification of the definition of BA 
transport water to exclude water remaining in a tank-based high recycle 
rate system at the end of the useful life of the facility.\14\ The EPA 
proposes not to characterize a technology basis for BAT/PSES applicable 
to such wastewater at this time.\15\
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    \13\ Although TSS is a conventional pollutant, as it did in the 
2015 rule, whenever EPA would be regulating TSS in any final rule 
following this proposal, it would be regulating it as an indicator 
pollutant for the particulate form of toxic metals.
    \14\ Under this modified definition, the water at the end of the 
useful life of the facility would be at most the volume of a full 
system. Since the high recycle rate system being selected as BAT 
allows for a 10 percent purge of the system volume each day, this 
would be the equivalent of 10 days discharge, a marginal, one-time 
increase in pollution.
    \15\ As illustrated above, there is a wide range of technologies 
currently in use for pollutant discharges associated with BA 
transport water, and new approaches continue to emerge. For the 
exclusion proposed today, permitting authorities would establish BAT 
limitations for such discharges on a site-specific, best 
professional judgement (BPJ) basis. 33 U.S.C. 1342 (a)(1)(B); 40 CFR 
124.3. Pretreatment program control authorities would need to 
develop local limitations to address the introduction of pollutants 
from this wastewater to POTWs that cause pass through or 
interference, as specified in 40 CFR 403.5(c)(2).
---------------------------------------------------------------------------

B. Rationale for the Proposed BAT

    In light of the criteria and factors specified in CWA sections 
304(b)(2)(B) and 301(b)(2)(A) (see Section IV of this preamble), the 
EPA proposes to

[[Page 64631]]

establish BAT effluent limitations based on the technologies described 
in Option 2.
1. FGD Wastewater
    This proposal identifies treatment using chemical precipitation 
followed by a low hydraulic residence time biological treatment 
including ultrafiltration as the BAT technology basis for control of 
pollutants discharged in FGD wastewater because after considering the 
factors specified in CWA section 304(b)(2)(B), the EPA proposes to find 
that this technology is available and economically achievable. More 
specifically, the technology basis for BAT would include the same 
chemical precipitation system described in the 2015 rule. Thus, it 
would employ equalization, hydroxide and sulfide (organosulfide) 
precipitation, iron coprecipitation, and removal of suspended and 
precipitated solids. This chemical precipitation system would be 
followed by a low hydraulic residence time, anoxic/anaerobic biological 
treatment system designed to remove heavy metals, selenium, and 
nitrate-nitrite.\16\ The LRTR bioreactor stage would be followed by an 
ultrafilter to remove suspended solids exiting the bioreactor, 
including colloidal particles.
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    \16\ Similar to the 2015 rule and consistent with discussions 
with engineering firms and facility staff, EPA assumed that in order 
to meet the limitations and standards, facilities would take steps 
to optimize wastewater flows as part of their operating practices 
(by reducing the FGD purge rate or recycling a portion of their FGD 
wastewater back to the FGD system), where the FGD system metallurgy 
can accommodate an increase in chlorides. See Section 5 of the 
Supplemental TDD.
---------------------------------------------------------------------------

    Both chemical precipitation and biological treatment are well-
demonstrated technologies that are available to steam electric 
facilities for use in treating FGD wastewater. In addition to the 39 
facilities mentioned as using chemical precipitation in the 2015 rule 
preamble, facilities have installed, or begun installation of such 
systems, because they have taken steps to cease using surface 
impoundments to treat their FGD wastewater. In addition, chemical 
precipitation has been used at thousands of industrial facilities 
nationwide for the last several decades as described in the 2015 rule 
record. Ultrafilters downstream of the biological treatment stage are 
designed for the removal of suspended solids exiting the bioreactor, 
such as any reduced, insoluble selenium, mercury, and other 
particulates. Ultrafiltration uses a membrane with pore size small 
enough to remove these smaller suspended particulates after the 
biological treatment stage, but still much larger than the pore size of 
the membrane technology (i.e., nanofiltration or reverse osmosis) that 
is the basis for option 4 and the VIP which is designed to remove 
dissolved metals and inorganics (e.g., nutrients, bromides, etc.). 
Unlike the nanofiltration and reverse osmosis technologies, 
ultrafilters do not generate a brine that would require encapsulation 
with fly ash or other disposal techniques. The types and amount of 
solids removed by the ultrafilter in the CP+LRTR treatment system are 
identical to the solids removed by the sand filter in the CP+HRTR 
treatment technology and do not result in the same non-water quality 
environmental impacts that are associated with the brine generated by 
the membrane technology of Option 4 and proposed for the VIP program.
    After accounting for the changes in the industry described in 
Section V of this preamble, fifteen steam electric facilities with wet 
scrubbers have technologies in place able to meet the proposed BAT 
effluent limitations for FGD wastewater.\17\ Of these fifteen 
facilities, nine are currently operating anoxic/anaerobic biological 
treatment designed to substantially reduce nitrogen compounds and 
selenium in their FGD wastewater. These biological treatment systems 
are a mix of low and high hydraulic residence time.\18\ The EPA 
identified a tenth facility that previously operated an anoxic/
anaerobic biological treatment system; however, more recently installed 
a thermal system for the treatment of FGD wastewater. Another five 
steam electric facilities are also operating thermal treatment systems 
for FGD wastewater.
---------------------------------------------------------------------------

    \17\ These fifteen facilities represent 11 percent of steam 
electric facilities with wet scrubbers. The EPA notes that a further 
40 percent of all steam electric facilities with wet scrubbers use 
FGD wastewater management approaches that eliminate the discharge of 
FGD wastewater altogether. But, although these technologies (which 
are described above in Section V.C.1) may be available for some 
facilities, none of them are available nationwide, and thus do not 
form the basis for the proposed BAT. For example, evaporation ponds 
are only available in certain climates. Similarly, complete recycle 
FGD systems are only available at facilities with appropriate FGD 
metallurgy. Facility conditions and availability of these 
technologies have not materially changed since the 2015 rule, and 
the EPA thus reaffirms that these technologies are not individually 
available nationwide and are not a basis for the proposed BAT.
    \18\ In addition to these nine facilities, some facilities 
employ other types of biological treatment. Some of these systems 
are sequencing batch reactors (SBR), which treat nitrogen, and that 
technology can be operated to remove selenium. The SBR systems 
currently operating at power facilities, however, would likely not 
be able to meet the limitations discussed in today's proposal 
without reconfiguration.
---------------------------------------------------------------------------

    In the 2015 rule, the EPA rejected three availability arguments 
made against biological treatment generally. The EPA is not proposing 
to change these findings based on record information received since the 
2015 rule but solicits comment on whether, and to what extent, these 
findings should be retained for the final rule. First, the EPA rejected 
the argument that maintaining a biological system over the long run was 
infeasible. Of the ten full-scale systems discussed above, four 
facilities have used the biological technology to treat FGD wastewater 
for more than a decade under varying operating conditions, climate 
conditions, and coal sources. Many pilot tests of the biological 
technology have been conducted at various facilities, and data from 
these tests demonstrate that even in the face of major upsets within 
the chemical precipitation stage of treatment, the biological stage 
continues to reduce selenium and nitrogen.
    In the 2015 rule, the EPA also rejected the argument that selenium 
removal efficacy was subject to the type of coal burned (specifically 
subbituminous coal) and coal-switching. Facilities have continued to 
operate biological treatment systems while switching coals and, in 
those cases, have maintained a consistent level of selenium removal. 
Furthermore, at least three pilot and two full-scale systems have now 
been successfully run or installed to treat FGD wastewater at 
facilities burning sub-bituminous coals or blends of bituminous and 
sub-bituminous coals, encompassing both HRTR and LRTR technologies.
    Finally, in the 2015 rule the EPA rejected arguments that cycling 
of facilities up and down in production, and even out of service for 
various periods of time, would affect the ability of facilities to meet 
the effluent limitations. Industry provided data for two facilities 
showing that they successfully operated biological systems while 
cycling operations and undergoing shutdowns in the years since the 2015 
rule.
    While the rationale above applies to both HRTR and LRTR 
technologies, the EPA proposes to establish BAT based on the LRTR 
technologies. LRTR reductions are comparable to HRTR reductions,\19\ 
are less costly, and require significantly less process or facility 
footprint modifications than the HRTR option. As explained in Section 
XIII of this preamble, the long-term averages forming the basis of the 
selenium limitations for LRTR and HRTR are similar, and the higher 
selenium

[[Page 64632]]

limitations for the LRTR systems are largely driven by increased short-
term variability around that average, rather than a meaningful 
difference in long-term pollutant removals.\20\
---------------------------------------------------------------------------

    \19\ For example, while the effluent from LRTR is more variable 
than HRTR, both technologies achieve long-term average effluent 
concentrations for selenium lower than 20 mg/L.
    \20\ Courts have recognized that while Section 301 of the CWA is 
intended to help achieve the national goal of eliminating the 
discharge of all pollutants, at some point the technology-based 
approach has its limitations. See Am. Petroleum Inst. v. EPA, 787 
F.2d 965, 972 (5th Cir. 1986) (``EPA would disserve its mandate were 
it to tilt at windmills by imposing BAT limitations which removed de 
minimis amounts of polluting agents from our nation's waters [. . 
.]'').
---------------------------------------------------------------------------

    LRTR is less costly than HRTR. Compared to the baseline of the 2015 
rule, LRTR is estimated to save approximately $72 million per year in 
after-tax costs to industry.
    LRTR requires fewer process changes than HRTR. Compared to HRTR, 
LRTR installations are less complex and require fewer modifications to 
a facility's footprint. The HRTR systems selected in the 2015 rule were 
large, concrete tanks which, along with their associated piping and 
pumping and control equipment, would be fabricated on site. By 
contrast, new LRTR systems have smaller footprints, and in many cases 
come prefabricated as modular components, including the ultrafilter 
polishing stage, requiring little more than a concrete foundation, 
electricity supply, and piping connections.
    The EPA is not proposing to establish BAT limitations or PSES based 
on chemical precipitation alone (Option 1). As the EPA noted during the 
development of the 2015 rule, chemical precipitation is effective at 
removing mercury, arsenic, and certain other heavy metals. While basing 
BAT limitations and PSES on this technology alone could save industry 
$103 million per year in after-tax costs relative to the 2015 rule, 
this technology alone does not remove nitrogen, nor does it remove the 
majority of selenium. Furthermore, the data in the EPA's record 
demonstrate that both LRTR and HRTR remove approximately 90 percent of 
the mercury remaining in the effluent from chemical precipitation 
treatment.\21\ Because the combination of chemical precipitation with 
LRTR provides substantial further reductions in the discharge of 
pollutants, the EPA proposes chemical precipitation followed by LRTR 
for BAT.
---------------------------------------------------------------------------

    \21\ Recall that the FGD mercury and arsenic limitations in the 
2015 rule were based on chemical precipitation data alone because 
the facilities operating biological systems were not using all of 
the chemical precipitation additives in the technology basis.
---------------------------------------------------------------------------

    The EPA is not proposing to establish BAT limitations based on 
membrane filtration (Option 4). Based on the EPA's record, the EPA 
could not conclude that membrane filtration is technologically 
available nationwide at this time, as the term is used in the CWA, but 
may become ``available'' on a nationwide basis by 2028 (this is 
reflected in the date of compliance for the VIP program under Options 2 
and 3). Furthermore, membrane filtration entails non-water-quality 
environmental impacts (associated with management of the brine) that 
the EPA proposes to find unacceptable.
    At the time of the 2015 rule, the EPA had no record of information 
about membrane filtration technologies being used to treat FGD 
wastewater. Since that time, the EPA collected information on several 
types of membrane filtration technologies. Microfiltration and 
ultrafiltration membranes are used primarily for removing suspended 
solids, including colloids. Nanofiltration, reverse osmosis, forward 
osmosis, and electrodialysis reversal (EDR) membranes are used to 
remove a broad range of dissolved pollutants. Each of these membrane 
filtration technologies generate both a treated effluent and a residual 
requiring further treatment or disposal. Microfiltration and 
ultrafiltration generate a solid waste residual which is disposed. 
Similarly, nanofiltration, reverse osmosis, forward osmosis, and EDR 
all produce a concentrated brine residual which must be disposed.
    The EPA's current record includes information on seven pilot 
studies of FGD wastewater treatment at domestic facilities using four 
different membrane filtration technologies.\22\ All of these 
technologies first employed some form of suspended solids removal such 
as microfiltration or chemical precipitation. This pretreated FGD 
wastewater was then fed into either nanofiltration or reverse osmosis 
membrane filtration systems.\23\ For several of the pilot studies, the 
resultant brines were mixed with FA and/or lime to test the potential 
for encapsulation of the concentrated brine wastestream.\24\
---------------------------------------------------------------------------

    \22\ Two of these pilot studies were completed in 2014, but 
information about these tests was not provided to EPA prior to the 
2015 rule.
    \23\ The EPA has also learned of an eighth pilot on an EDR 
system, but no data have yet been provided (https://www.filtsep.com/water-and-wastewater/news/saltworks-completes-fgd-pilot-in-us/).
    \24\ The record includes additional encapsulation studies and 
data not explicitly linked to these seven pilots.
---------------------------------------------------------------------------

    The EPA is not aware of any domestic facilities which have to date 
installed nanofiltration or reverse osmosis membrane filtration systems 
to remove dissolved pollutants in FGD wastewater, although EPA is aware 
of three facilities in China which have installed such membrane 
filtration systems.\25\ The record contains limited information about 
these facilities. Two of the facilities employ pretreatment and a 
combination of reverse osmosis and forward osmosis. The EPA does not 
have detailed information about the specific configurations or the 
long-term performance of these two systems, nor is the EPA aware of how 
the resultant brine is being disposed.\26\ Furthermore, the company 
that sold these two systems has since ceased commercial operations.\27\ 
The third facility operating in China employs pretreatment followed by 
nanofiltration and reverse osmosis. At this facility, the brine is 
crystallized and the resulting salt is sold for industrial uses. The 
EPA does not have information on the long-term performance of this 
system.
---------------------------------------------------------------------------

    \25\ Ultrafiltration has been installed as part of FGD 
wastewater treatment systems in the U.S.; however, these membranes 
are intended to remove suspended solids, not dissolved pollutants.
    \26\ This is in contrast to biological treatment systems for 
which EPA has long-term performance data. Although LRTR and HRTR 
systems differ in their configuration (e.g., residence time), the 
underlying performance has been well demonstrated on this 
wastewater.
    \27\ The following story summarizes the forward osmosis company 
Oasys ceasing commercial operations: https://www.bluetechresearch.com/news-blog/comment-oasys-hits-funding-drought/.
---------------------------------------------------------------------------

    While the EPA does have some information about the use of membrane 
filtration on FGD wastewater from pilot studies, uncertainty remains 
regarding operation of the suite of membrane filtration technologies 
evaluated by the EPA as the basis for Option 4. With respect to data 
from the pilot studies, these studies focused on membrane technologies 
that would remove dissolved pollutants. For the technologies designed 
to remove dissolved pollutants, several studies either did not include 
a second stage of membrane filtration (i.e., a reverse osmosis 
polishing stage which electric utilities and vendors indicated would 
need to be part of any potential future membrane filtration system they 
would install and operate with a discharge) or provided only summaries 
of effluent data because of nondisclosure agreements between EPRI, 
treatment technology vendors, and/or the plant operators. In both 
cases, this prevented the EPA from fully analyzing the pollutant 
removal efficacy and effluent variability associated with the treatment 
systems used in those studies. The pilot tests that omitted the second 
stage of membrane filtration do not provide sufficient insight into the 
performance capabilities of the membrane technology because the initial 
membrane filtration step (e.g., a nanofilter unit) does not by

[[Page 64633]]

itself remove the broad range of pollutants as effectively as would be 
achieved by the two-stage configuration. The pilot tests for which the 
EPA has only summary-level data provide summary statistics, such as the 
observed range of pollutant concentrations, average influent and 
effluent pollutant concentrations, and duration of the testing periods. 
However, the EPA lacks the individual daily sample results that are 
needed to fully evaluate treatment system operation and calculate 
effluent limitations. Complete data sets were only available from three 
pilot facilities using a single vendor's reverse osmosis 
technology.\28\
---------------------------------------------------------------------------

    \28\ These three data sets served as the basis of the proposed 
revisions to the VIP limitations, described further in Section XIII 
of this preamble. These limited data sets do not provide sufficient 
information to evaluate the performance of nanofiltration and 
reverse osmosis membrane filtration technology as the primary 
treatment for dissolved pollutants FGD wastewater. The EPA 
anticipates that additional pilots, tests and data collection could 
result in these technologies becoming available by the VIP 
compliance date of 2028. By contrast and for the reasons explained 
in section VII.2.B., the EPA proposes to conclude that 
ultrafiltration technology is available for use in the polishing 
stage for systems using LRTR biological systems as the primary 
treatment technology for FGD wastewater.
---------------------------------------------------------------------------

    In addition, while the EPA does have information about membrane 
filtration application to FGD wastewater from bids and engineering 
documents, those sources express concerns about operating a technology 
on this wastewater that would be the first of its kind in the U.S. With 
respect to information from bids for full-scale installations and 
related documents, the EPA obtained copies of bids that represented a 
single vendor's reverse osmosis-based technology and that incorporated 
performance guarantees. Such guarantees, which are standard within the 
steam electric power generating industry, act to transfer the costs of 
specific performance issues from the purchaser of the equipment to the 
vendor. While the willingness of this vendor to take on these risks 
might suggest confidence in the long-term performance of its 
technology, third-party EPC firms with no vested interest in the 
technology are hesitant to recommend that a client be the first site in 
the U.S. to adopt membrane filtration for the treatment of FGD 
wastewater because of uncertainty related to system performance and the 
ability to operate successfully without frequent, if not excessive, 
chemical cleaning. This further supports EPA's proposal to find, at 
this time, that membrane filtration is not, technologically available 
or an appropriate basis for mandatory requirements for the entire 
industry. The EPA solicits comment on this availability finding, and 
whether membrane filtration may become nationally available sooner or 
later than 2028.
    The EPA also rejects membranes as the technology basis for BAT for 
all existing facilities because it could discourage more valuable forms 
of beneficial reuse of FA (such as replacing Portland cement in 
concrete) potentially causing more FA to be incorporated in wastes 
being disposed.\29\ While there are several alternative ways to treat 
or dispose of the brine generated by membrane filtration, the method 
most likely to be employed (based on bids, engineering documents, and 
discussions with electric utilities) is encapsulation with FA and lime 
for disposal of the resulting solid in a landfill.\30\
---------------------------------------------------------------------------

    \29\ While the EPA considers FA use for waste solidification and 
stabilization as beneficial use, the CCR waste being solidified or 
stabilized must still be disposed of in accordance with 40 CFR 257.
    \30\ Bids also indicate that this would be the least-cost brine 
management alternative.
---------------------------------------------------------------------------

    Landfilling an encapsulated material raises challenges. For 
instance, comingling might result in a leachate blowout. The King 
County Landfill in Virginia experienced a leachate blow out when 
compact CCR materials with a low infiltration rate were layered with 
normal municipal solid waste having a higher infiltration rate. 
Similarly, in the case of encapsulated brine paste, the paste would set 
and thereafter achieve a very low infiltration rate. When comingled 
with CCRs having a higher infiltration rate, this would lead to layers 
with disparate infiltration rates akin to those experienced in the King 
County scenario. Thus, segregation of low infiltration rate 
encapsulated brine in a landfill cell separate from other, higher 
infiltration wastes could be necessary to prevent this layering, and a 
potential leachate blowout. Such dedicated landfill cells do not exist 
today, and would require time to permit and construct.
    Moreover, instead of disposing of their FA, facilities can sell it 
for beneficial use. As stated in the 2015 CCR rule:

    The beneficial use of CCR is a primary alternative to current 
disposal methods. And as EPA has repeatedly concluded, it is a 
method that, when performed correctly, can offer significant 
environmental benefits, including greenhouse gas (GHG) reduction, 
energy conservation, reduction in land disposal (along with the 
corresponding avoidance of potential CCR disposal impacts), and 
reduction in the need to mine and process virgin materials and the 
associated environmental impacts.\31\
---------------------------------------------------------------------------

    \31\ 80 FR 21329 (April 17, 2015).

    According to 2016 EIA data, the median percent of FA sold for 
beneficial use by the facilities with wet FGD systems is approximately 
fifty percent, with a range of zero to one hundred percent. The fact 
that encapsulation with FA and lime is the most likely, and least cost, 
brine management method that facilities could employ nationally, 
combined with the high percent of FA currently being beneficially used, 
indicates that selection of membrane filtration as BAT could discourage 
environmentally preferable beneficial uses of FA, such as replacement 
of Portland cement in concrete.\32\ Specifically, the Agency estimated 
in U.S. EPA (2011) that each ton of fly ash used as a substitute for 
Portland cement would avoid 5,400 megajoules of nonrenewable energy 
use, 690 liters of water use, 1,000,000 grams (g) of CO2 
emissions, 840 g of methane emissions, 1,400 g of CO emissions, 2,700 g 
of NOX emissions, 2,500 g of SOX emissions, 2,400 
g of PM, 0.08 g of Hg, 490 g of TSS discharge, 23 g of BOD discharge, 
and 46 g of COD discharge.\33\ After considering these cross-program 
environmental impacts, the EPA proposes to find that discouraging this 
beneficial use of FA would result in unacceptable non-water-quality 
environmental impacts.
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    \32\ Although the EPA evaluated FA and lime encapsulation as the 
least-cost nationally available brine disposal alternative, other 
alternatives may have higher costs and non-water quality 
environmental impacts. For example, if a facility chose to 
crystallize the resulting brine to continue selling its FA, this 
thermal crystallization process could have a higher cost and 
parasitic energy load.
    \33\ U.S. EPA (Environmental Protection Agency). 2011. Waste and 
Materials--Flow Benchmark Sector Report: Beneficial Use of Secondary 
Materials--Coal Combustion Products. Office of Solid Waste and 
Emergency Response. Washington, DC 20460. April.
---------------------------------------------------------------------------

    Finally, while the EPA views the foregoing reasoning as sufficient 
to find that membrane filtration is not BAT for all existing sources, 
the EPA notes that membrane filtration is projected to cost industry 
more than the proposed BAT option for FGD wastewater, i.e., chemical 
precipitation plus LRTR. Added to these costs are the costs to 
facilities of disposing of the resulting brine. Some facilities that 
otherwise sell their FA may choose to use their FA to encapsulate the 
brine, thereby foregoing revenue from FA sales. Other facilities that 
choose to continue to sell their FA must dispose of the brine using 
another disposal alternative, such as crystallization, at an additional 
cost. Costs are a separate statutory factor that the EPA considers in 
selecting BAT (see, for example, BP Exploration & Oil, Inc. v. EPA, 66 
F.3d 784, 796 (6th Cir. 1996).

[[Page 64634]]

Here, while these costs do not make the membrane filtration option 
economically unachievable, the additional costs associated with 
membrane filtration provide additional support for the EPA's proposal 
that membrane filtration is not BAT for all existing sources.
    Although the EPA is proposing to reject membranes as the national 
technology basis for BAT, the EPA proposes to establish a VIP based on 
membrane technology, as discussed later in this section. The EPA 
solicits comment on this conclusion. Furthermore, the EPA solicits 
comment on whether there are early adopters who have already contracted 
for, purchased, or installed biological technology for compliance with 
the 2015 rule, and whether these facilities should be included as a 
subcategory not subject to the final BAT of Option 4, if finalized. The 
EPA solicits comment on whether such a subcategory could be based on 
the age of the new pollution control equipment that had not yet lived 
out its useful life, the disparate costs of purchasing two sets of 
equipment, or other statutory factors.
    As described further below, the EPA is also not proposing to 
establish BAT limitations based on other technologies also evaluated in 
the 2015 rule.
    First, except for the end of life boiler and low-utilization 
subcategories discussed below, the EPA is not proposing to establish 
BAT limitations based on surface impoundments. Surface impoundments are 
not as effective at controlling pollutants like dissolved metals and 
nutrients as available and achievable technologies like CP and LRTR. 
EPA drew a similar conclusion in the 2015 rule, and nothing in the 
record developed by the Agency since the 2015 rule would change this 
determination.
    Second, the EPA is not proposing to establish BAT limitations based 
on thermal technologies, such as chemical precipitation (including 
softening) followed by a falling film evaporator, on the basis of high 
costs to industry. In the 2015 rule, the EPA rejected this technology 
as a basis for BAT limitations due to high costs to industry. Since the 
2015 rule, the EPA has collected additional information on full-scale 
installations and pilots of thermal technologies to treat FGD 
wastewater. The EPA's record includes information about approximately 
10 pilot studies conducted in the U.S., providing performance data for 
five different thermal technologies. In addition, full scale 
installations are operating at six facilities,\34\ and a seventh 
purchased thermal equipment, but elected not to install it.\35\ While 
new thermal technologies have been pilot tested and used at full-scale 
since the 2015 rule, and related cost information demonstrates that 
thermal technologies are less costly than estimated for the 2015 rule, 
the thermal costs evaluated in the EPA's memorandum FGD Thermal 
Evaporation Cost Methodology (DCN SE07098) are still three to five 
times higher than any other option presented in Table VIII-1. As 
authorized by section 304(b) of the CWA, which allows the EPA to 
consider costs, the Agency is not proposing that thermal technologies 
are BAT due to the unacceptable costs to industry. Given the high costs 
associated with the technology, and the fact that the steam electric 
power generating industry continues to face costs associated with 
several other rules, in addition to this rule, the EPA is not proposing 
to establish BAT limitations for FGD wastewater based on evaporation 
for all steam electric facilities. The EPA solicits comment on this 
finding, as well as the accuracy of the revised costs estimates.
---------------------------------------------------------------------------

    \34\ One of these facilities successfully ran three different 
thermal systems to treat its wastewater, transitioning from a 
falling film evaporator to a direct-contact evaporator that mixes 
hot gases in a high turbulence evaporation chamber, and finally to a 
spray dryer evaporator.
    \35\ This facility purchased a falling film evaporator for the 
purpose of meeting water quality-based effluent limitations for 
boron, but then elected to instead pay approximately $1 million per 
year to send its wastewater to a local POTW.
---------------------------------------------------------------------------

    Furthermore, since membrane filtration technologies included in 
Option 4 appear to achieve similar pollutant removals for lower costs 
than thermal, the EPA is proposing to revise the basis for the VIP 
limitations adopted in the 2015 rule to membrane filtration, instead of 
thermal technologies, as discussed later in this section.\36\ The EPA 
solicits comment on the extent to which membrane filtration 
technologies could be used in lieu of, or in combination with, thermal 
technologies.
---------------------------------------------------------------------------

    \36\ The EPA notes that thermal technologies could continue to 
be used to meet the voluntary incentives program limitations based 
on membrane filtration.
---------------------------------------------------------------------------

    Finally, the EPA is not proposing to decline to establish BAT and 
leave BAT effluent limitations for FGD wastewater to be established by 
the permitting authority using BPJ. The EPA explained in the 2015 rule 
why BPJ determinations would not be appropriate for FGD wastewater, 
particularly given the availability of several other technologies, and 
nothing in EPA's record would alter its previous conclusion.
2. BA Transport Water
    This proposal identifies treatment using high recycle rate systems 
as the BAT technology basis for control of pollutants discharged in BA 
transport water because, after evaluating the factors specified in CWA 
section 304(b)(2)(B), the EPA proposes to find that this technology is 
available and economically achievable. In the 2015 rule, the EPA 
selected dry BA handling or closed-loop wet ash handling systems as the 
technology basis for the ``zero discharge'' BAT requirements for BA 
transport water. The EPA established zero pollutant discharge 
limitations based on these technologies and included a limited 
allowance for pollutant discharges associated with certain maintenance 
activities.\37\
---------------------------------------------------------------------------

    \37\ See 40 CFR part 423.11(p).
---------------------------------------------------------------------------

    At the time of the 2015 rule, the EPA estimated that more than 50 
percent of facilities already employed dry handling systems or wet 
sluicing systems designed to operate closed-loop, or had announced 
plans to switch to such systems in the near future. Based on new 
information collected since the 2015 rule, that value is now over 75 
percent, nearly evenly split between dry and wet systems. However, 
since the 2015 rule, the EPA's understanding of the types of available 
dry systems, and the ability of wet systems to achieve complete recycle 
has changed, as discussed below.
    There have been advances in dry BA handling systems since the 2015 
rule.\38\ For example, in addition to under-boiler mechanical drag 
chain systems (described in the 2015 rule), pneumatic systems and 
submerged grinder conveyors are now available and in use at some 
facilities. Such systems often can be installed at facilities that are 
constrained from retrofitting a mechanical drag system due to 
insufficient vertical space under the boiler.
---------------------------------------------------------------------------

    \38\ The term ``dry handling'' is used to refer to ash handling 
systems that do not use water as the transport medium for conveying 
ash away from the boiler. Such systems include pneumatic and 
mechanical processes (some mechanical processes use water to cool 
the BA or create a water seal between the boiler and ash hoppers, 
but the water does not act as the transport medium).
---------------------------------------------------------------------------

    With respect to wet BA handling systems, in their petitions for 
reconsideration and in recent meetings with the EPA, utilities and 
trade associations informed the EPA that many existing remote wet 
systems are, in reality, ``partially closed'' rather than closed-loop, 
as indicated by the EPA in

[[Page 64635]]

the 2015 rule. Utilities and trade associations informed the EPA that 
these systems operate partially closed, rather than closed, due to 
small discharges associated with additional maintenance and repair 
activities not accounted for in the 2015 maintenance allowances,\39\ 
water imbalances within the system such as those associated with 
stormwater,\40\ and water chemistry imbalances including acidity and 
corrosiveness, scaling, and fines build-up. While some facilities have 
controlled or eliminated these challenges with relatively 
straightforward steps (See DCNs SE08179 and SE06963), others require 
more extensive process changes and associated increased costs or find 
them difficult to resolve (See DCNs SE08188, SE08180, and SE06920).
---------------------------------------------------------------------------

    \39\ The 2015 rule maintenance discharges were characterized as 
not a significant portion of the system volume, compared to, for 
example, potential discharges resulting from maintenance of the 
remote MDS tank or the conveyor itself. Such maintenance could 
require draining the entire system, which would not be permissible 
under the 2015 rule maintenance discharge allowance.
    \40\ The 2015 rule provided no exemption or allowance for 
discharges due to precipitation events. While systems are often 
engineered with extra capacity to handle rainfall/runoff from a 
certain size precipitation event, these events may occur back-to-
back, or facilities may receive events with higher rates of 
accumulation beyond what the facility was designed to handle.
---------------------------------------------------------------------------

    The EPA agrees that the new information indicates that some 
facilities with wet ash removal systems generally operate as zero 
discharge systems, but in many cases must operate as high recycle rate 
systems. While some facilities currently handle the challenges 
discussed above by discharging some portion of their BA transport water 
(as the zero discharge limitations in the 2015 rule are not yet 
applicable), the record demonstrates that facilities can likely 
eliminate such discharges with additional process changes and 
expenditures. Just as the EPA estimated costs of chemical additions in 
the 2015 rule to manage scaling, companies could add additional 
treatment chemicals (caustic) to manage acidity or other chemicals to 
control alkalinity, make use of reverse osmosis filters to treat a slip 
stream of the recycled water to remove dissolved solids, add polymer to 
enhance settling and removal of fine particulates (``fines''), and 
build storage tanks to hold water during infrequent maintenance or 
precipitation events. Industry-wide, the EPA estimates the costs of 
fully closing the loop to be $43 million per year in after-tax costs, 
above and beyond the costs of the systems themselves.\41\ These 
additional costs and process changes were not accounted for in the 2015 
rule; however, as discussed in Section 5.3 of the Supplemental TDD, in 
estimating the baseline costs of the BA limitations in the 2015 rule, 
the EPA now accounts for these costs. The EPA solicits comment on 
whether these assumptions and costs are appropriate and requests 
commenters identify and include available data or information to 
support their recommended approach.
---------------------------------------------------------------------------

    \41\ Utilities and EPC firms have discussed the availability of 
new dry systems, such as the submerged grinder conveyor or pressure 
systems, which at some facilities would have costs similar to 
recirculating wet systems that would require a purge. Because the 
EPA did not have cost information to determine the subset of 
facilities for which new dry systems might be least costly, some 
portion of the costs estimated for this proposal may be based on 
selecting recirculating wet systems at facilities which could 
ultimately go dry. Thus, the EPA may overestimate costs or 
underestimate pollutant removals at the subset of facilities where 
such a dry system would be selected.
---------------------------------------------------------------------------

    The EPA also recognizes the need for facilities to consider the 
standards of multiple environmental regulations simultaneously. As 
discussed in Section IV above, the EPA is separately proposing changes 
to the CCR rule that, if finalized, would allow facilities to cease 
receiving waste in unlined surface impoundments by August 2020.\42\ The 
challenges of operating a truly closed-loop system discussed above are 
compounded when considered in conjunction with the requirements of the 
CCR rule. Facilities often send various CCR and non-CCR wastestreams, 
such as coal mill rejects, economizer ash, etc., with BA transport 
water into their surface impoundments. According to reports provided to 
the EPA and conversations with electric utilities, several facilities 
have already begun the transition away from impoundments, and also use 
the BA treatment system for some of their non-CCR wastewaters.\43\ This 
reportedly can lead to or exacerbate problems with scaling, corrosion, 
or plugging of equipment that complicate achievement of a closed-loop 
system and require additional process changes and expense to address. 
All of which problems could be avoided by purging the system from time 
to time, as necessary. While those facilities that have not yet 
installed a BA transport water technology (less than 25 percent) could 
potentially employ a dry system, and those facilities with existing wet 
systems could potentially segregate their BA transport water from their 
non-CCR wastewaters, short compliance timeframes under the CCR rule may 
limit the availability of such options.
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    \42\ As discussed in Section IV of this preamble, further 
information about this proposal is available at http://www.regulations.gov, Docket EPA-HQ-OLEM-2019-0172.
    \43\ In some cases, the treatment system predated even the 
proposed CCR rule.
---------------------------------------------------------------------------

    In light of the foregoing process changes (and associated 
engineering challenges) that facilities would need to make to implement 
a true zero discharge BA transport water limitation in combination with 
the CCR rule, and to give facilities flexibilities that will facilitate 
orderly compliance with the fast-approaching CCR rule deadlines, the 
EPA proposes to base the BA transport water BAT limitations on the use 
of dry handling or high recycle rate systems rather than dry handling 
or closed-loop systems, the technologies on which the zero discharge 
BAT limitation adopted in the 2015 rule were based. The EPA's proposal 
is based on its discretion to give particular weight to the CWA Section 
304(b) statutory factor of ``process changes.'' Process changes to 
existing high recycle rate systems that do not currently operate as 
closed loop, or that will be installed in the near-future, to comply 
with this rule in conjunction with the CCR rule as discussed above 
could be more challenging without a further discharge allowance, and in 
some cases could also result in the prolonged use of unlined surface 
impoundments.
    The EPA considers that the factors discussed above are sufficient 
to support the Agency's decision not to select closed-loop systems as 
BAT for BA transport water. The EPA also notes that cost is a statutory 
factor that it must consider when establishing BAT, and that closed-
loop systems cost more than high recycle rate systems for treatment of 
BA transport water. While the EPA does not find this higher cost to be 
economically unachievable, the higher cost of closed loop systems is an 
additional reason for the EPA to not select closed loop systems as BAT 
for treating BA transport water.
    Under the proposed option, the EPA would allow facilities with a 
wet transport system, on an ``as needed'' basis, to discharge up to 10 
percent of the system volume per day on a 30-day rolling average to 
account for the challenges identified above, including infrequent large 
precipitation and maintenance events. The EPA proposes that the term 
``30-day rolling average'' means the series of averages using the 
measured values of the preceding 30 days for each average in the 
series. This does not mean that the EPA expects all facilities to 
discharge up to 10 percent on a regular basis, rather this option is 
designed to provide flexibility if and when needed to address site-
specific challenges of operating the recirculating

[[Page 64636]]

ash system (for more on implementation, see Section XIV of this 
preamble).\44\ The EPA also solicits comment on a facility-specific 
recycle rate alternative to the 10 percent 30-day rolling average 
option. Under such an alternative, each facility operating a high 
recycle rate system would take proactive measures (e.g., acid or 
caustic addition for pH control, chemical addition to control 
alkalinity, polymer addition to remove fines) to maintain system water 
chemistry within control limitations established by the facility in a 
BMP plan similar to that proposed for low utilization units in Section 
VII.C.2 below. Under this approach, when reasonable active measures are 
insufficient to maintain system water chemistry or water balance within 
acceptable limitations, or to facilitate maintenance and repairs of the 
BA system, the facility would be authorized to purge a portion of the 
system volume. The purge volume would be determined based on plant-
specific information and would be minimized to the extent feasible and 
limited to a maximum of 10 percent of the total system volume. The EPA 
solicits comment on whether these two options provide sufficient notice 
and regulatory certainty for facilities to understand potential 
obligations under the proposed rule and associated costs. The EPA 
solicits comment on an alternate approach that establishes a standard 
purge rate of 10 percent that can be adjusted upward or downward based 
on site-specific operating data. Finally, the EPA solicits comment on 
whether these discharges should be capped at a specific flow. The EPA 
requests commenters identify and include available data or information 
to support their recommended approach.
---------------------------------------------------------------------------

    \44\ The EPA's pollutant loading analyses provided in Section 
IX.B of this preamble and described in detail in the BCA Report and 
Supplemental TDD were based on an assumed 10 percent purge at each 
affected facility.
---------------------------------------------------------------------------

    Under either option discussed above for determining discharge 
allowances (10 percent 30-day rolling average or site-specific), there 
may be wastewater from whatever is purged by the high recycle rate 
system, and plants may wish to discharge this wastewater. Two 
considerations make determining a nationwide BAT for these discharges 
challenging and fact-specific. First, in the case of precipitation or 
maintenance-related purges, such purges would be potentially large 
volumes at infrequent intervals.\45\ Each facility necessarily has 
different climates and maintenance needs that could make selecting a 
uniform treatment system more difficult. Second, utilities have stated 
that discharges of wastewater associated with high rate recycle systems 
are sent to low volume wastewater treatment systems, which are 
typically dewatering basins or surface impoundments. Many of these 
systems are in transition as a result of the CCR rule. New wastewater 
treatment systems installed for low volume wastewater and other 
wastestreams (which could be used to treat the wastewater purged from a 
high recycle rate system), as well as the types of wastestreams 
combined in such systems, are likely to vary across facilities.
---------------------------------------------------------------------------

    \45\ In the case of precipitation, rainfall exceeding a 25 year, 
24-hour event may only happen once during the 20-year lifetime of 
the equipment, if at all.
---------------------------------------------------------------------------

    In light of the information discussed above, and the EPA's 
authority under section 304(b) to consider both the process employed 
(for maintenance needs) and process changes (for new treatment systems 
installed to comply with the CCR rule), the EPA proposes that BAT 
limitations for any wastewater that is purged from a high recycle rate 
system and then discharged be established by the permitting authority 
on a case-by-case basis using BPJ. The EPA assumes permitting 
authorities will be in a better position than the EPA to examine site-
specific climate and maintenance factors for infrequent events. 
Permitting authorities will also be in a better position than the EPA 
to account for site-specific treatment technologies and their 
configurations already installed or being installed to comply with the 
CCR rule and other regulations which could accommodate the volumes of, 
and successfully treat, any discharges of wastewater from a high 
recycle rate system associated with the proposed allowance. The EPA 
also solicits comment on technologies that could serve as the basis for 
BAT for this discharge and what technologies state permitting 
authorities may consider as BPJ. For example, the EPA solicits comment 
on whether surface impoundments could be selected as BAT based on high 
costs to control the purge with other technologies. The EPA further 
solicits comment on whether delaying the selection of appropriate 
treatment technology though the BPJ process masks the true cost of this 
proposed rule for both the regulated entity and the regulatory agency 
that must undertake the evaluation and ultimately establish BPJ. The 
EPA also solicits comment on whether the EPA should constrain BPJ by 
precluding the consideration of some technologies (e.g., zero 
discharge) using nationwide application of the statutory factors. The 
EPA solicits any data, information or methodologies that may be useful 
in evaluating the potential costs of establishing and complying with as 
yet undetermined BPJ requirements.
    The EPA is not proposing to identify surface impoundments as BAT 
for BA transport water except for BATW purge water because surface 
impoundments are not as effective at removing dissolved metals as 
available and achievable technologies, such as high recycle rate 
systems. Furthermore, the record since the 2015 rule shows that 
facilities have continued to convert away from surface impoundments to 
the types of technologies described above, either voluntarily or due to 
the CCR rule, and in 2018, the U.S. Court of Appeals for the District 
of Columbia vacated that portion of the 2015 CCR rule that allowed both 
unlined and clay-lined surface impoundments to continue operating. 
USWAG v. EPA, No. 15-1219 (D.C. Cir. 2018). Since very few CCR surface 
impoundments are composite-lined, the practical effect of this ruling 
is that the majority of facilities with operating ponds likely will 
cease sluicing waste to their ponds in the near future. In the 2015 CCR 
rule, the EPA estimated that it would be less costly for facilities to 
install under-boiler or remote drag chain systems and send BA to 
landfills rather than continue to wet sluice BA and replace unlined 
ponds with composite lined ponds. This supports the suggestion that 
surface impoundments are not BAT for all facilities. However, the EPA 
proposes to identify surface impoundments as BAT for two subcategories, 
as discussed later in this section.
3. Rationale for Voluntary Incentives Program (VIP)
    As part of the BAT for existing sources, the 2015 rule established 
a VIP that provided the certainty of more time (until December 31, 2023 
instead of a date determined by the permitting authority that is as 
soon as possible beginning November 1, 2018) for facilities to 
implement new BAT limitations if they adopted additional process 
changes and controls that achieve limitations on mercury, arsenic, 
selenium and TDS in FGD wastewater, based on thermal evaporation 
technology. See Section VIII(C)(13) of the 2015 rule preamble for a 
more complete description of the selection of the thermal technology 
basis, chemical precipitation (with softening) followed by a falling 
film evaporator. The EPA expected this additional time, combined with 
other factors (such as the possibility that a facility's NPDES

[[Page 64637]]

permit may need more stringent limitations to meet applicable water 
quality standards), would lead some facilities to choose this option 
for future implementation by incorporating the VIP limits into their 
permit during the permit application process. New information in 
several utilities' internal analyses and contractor reports provided to 
the EPA since the 2015 rule, as well as meetings with utilities, EPC 
firms, and vendors indicates that facility decisions to install the 
more expensive thermal systems were driven by water quality-based 
effluent limitations imposed by the NPDES permitting authority. 
Furthermore, such documents and meetings also show that several 
facilities considered installing membrane filtration technologies under 
the 2015 rule VIP as well, and thus the EPA evaluated membrane 
filtration as an alternative basis for VIP.
    The EPA proposes to revise the VIP limitations established in the 
2015 rule using membrane filtration as the technology basis because it 
costs less than half the cost of thermal technology and has comparable 
pollutant removal performance. Membrane filtration achieves pollutant 
removals comparable to thermal systems in situations where the thermal 
system would discharge. Engineering documents for some individual 
facilities evaluated this technology as a zero liquid discharge system 
which would recycle permeate into the plant. Due to the higher costs of 
thermal systems compared to chemical precipitation followed by LRTR, 
the EPA does not expect that any facility would install a new thermal 
system under the 2015 rule VIP as the least cost technology. As 
authorized by section 304(b) of the CWA, which allows the EPA to 
consider costs, the EPA proposes membrane filtration as the technology 
basis for the VIP BAT limitations, with limitations for mercury, 
arsenic, selenium, nitrate-nitrite, bromide, and TDS.\46\
---------------------------------------------------------------------------

    \46\ Note that the 2015 rule did not include limitations for 
nitrate/nitrite or bromide.
---------------------------------------------------------------------------

    Second, as authorized by section 304(b) of the CWA, which allows 
the EPA to consider process changes and non-water quality environmental 
impacts, the EPA proposes to revise the compliance date for the VIP 
limitations to December 31, 2028. That is the date the EPA has 
determined that the membrane filtration technology will be available 
nationwide, as that term is used in the CWA, for those facilities who 
choose to adopt it. This timeframe is based on the amount of time 
necessary to pilot, design, procure, and install both the membrane 
filtration systems and the brine management systems. The EPA notes that 
this is similar to the eight-year period between promulgation of the 
2015 rule and the 2023 deadline for the current voluntary incentives 
program. The EPA proposes to find that forthcoming changes in membrane 
filtration brine disposal options may significantly reduce the non-
water quality environmental impacts associated with encapsulation, 
discussed in Section VII(b)(i) above. Through discussions with several 
utilities and EPRI, the EPA learned that a forthcoming paste technology 
may allow facilities to mix the brine with lower quantities of FA and 
lime and pump the resulting paste via pipes to an onsite landfill where 
the paste would self-level prior to setting as an encapsulated 
material. According to these discussions, such a process may be less 
costly than existing brine disposal alternatives. This process could 
also reduce non-water quality environmental impacts by reducing the 
amount of FA used, decreasing air emissions and fuel use associated 
with trucking and spreading, and, where FA is already being disposed 
of, could reduce the volumes and pollutant concentrations in 
leachate.47 48 A compliance date of December 31, 2028, would 
have the advantage of allowing this forthcoming paste technology 
potentially enough time to become available, allow facilities more time 
to permit landfill cells for brine encapsulated with FA and lime if 
needed, and conduct pilot testing, demonstrations, and further analyses 
to fully understand and incorporate the process changes associated with 
membrane filtration operation, and understand the long term performance 
of the technology for treatment of FGD waste.
---------------------------------------------------------------------------

    \47\ Sniderman, Debbie. 2017. From Power Plant to Landfill: 
Encapsulation. Innovative Technology Offers Elegant Solution for 
Disposing of Multiple Types of Waste. EPRI Journal. September 19. 
Available online at: http://eprijournal.com/from-power-plant-to-landfill-encapsulation/.
    \48\ Although the EPA is not establishing BAT for leachate in 
the current rulemaking, the vacatur and remand of BAT for leachate 
in Southwestern Electric Power Co., et al. v. EPA means that 
decreasing volumes of leachate and the concentration of pollutants 
in that leachate might make more technologies available in a future 
BAT rulemaking.
---------------------------------------------------------------------------

    One remaining challenge identified for this paste technology is 
developing approaches to manage wastes (e.g., flush water) from 
periodic cleaning of the paste transportation piping, where such piping 
is used.\49\ As authorized by section 304(b) of the CWA, which allows 
the EPA to consider the process employed, the EPA is proposing a 
modification of the definition of FGD wastewater and ash transport 
water to explicitly exclude water used to clean FGD paste piping so 
that facilities using paste piping for brine encapsulation and disposal 
in an on-site landfill can more easily clean residual paste from pipes.
---------------------------------------------------------------------------

    \49\ Utilities described this process as water pushing a ball 
through the paste piping when not in use, based on cleaning done of 
concrete pipes at construction sites. While the ball would clean out 
the majority of the paste, water would still contact incidental 
amounts of ash and FGD materials, thus potentially subjecting it to 
regulations for those wastewaters.
---------------------------------------------------------------------------

    Taken together, the EPA's proposed changes to the VIP would give 
facilities greater flexibility when choosing a technology, while 
continuing to achieve pollutant reductions beyond the BAT limitations 
that are generally applicable to the industry and currently available 
nationwide. Under Option 2, the EPA estimated that 18 plants (27 
percent of plants estimated to incur FGD compliance costs) may opt into 
the VIP program and under Option 3 the number rises to 23 plants (34 
percent of plants estimated to incur FGD compliance costs). The EPA 
solicits comment on the accuracy of the cost estimates indicating that 
these plants would opt into the revised VIP program, including data 
identifying costs that may be potentially excluded from this analysis. 
Specifically, the EPA solicits data and information on any potential 
technology limitations, commercial availability, and other limitations 
that may affect plants' ability to adopt the VIP limits by the proposed 
VIP compliance date of 2028.

C. Additional Proposed Subcategories

    In the 2015 rule, the EPA established subcategories for small 
boilers (<50 MW nameplate capacity) and oil-fired units. The EPA 
subcategorized small boilers due to disproportionate costs when 
compared to the rest of the industry and subcategorized oil-fired 
boilers both because they generated substantially fewer pollutants and 
are generally older \50\ (and more susceptible to early retirement). In 
the 2015 rule, the EPA stated:
---------------------------------------------------------------------------

    \50\ Age is a statutory factor for BAT. CWA section 304(b), 233 
U.S.C. 1304(b).

    If these units shut down, EPA is concerned about resulting 
reductions in the flexibility that grid operators have during peak 
demand due to less reserve generating capacity to draw upon. But, 
more importantly, maintaining a diverse fleet of generating units 
that includes a variety of fuel sources is important to the nation's 
energy security. Because the supply/delivery network for oil is 
different from other fuel sources, maintaining the existence of oil-
fired generating units helps ensure reliable electric

[[Page 64638]]

power generation, as commenters confirmed. \51\
---------------------------------------------------------------------------

    \51\ 80 FR 67856.

    For these subcategorized units, in the 2015 rule the EPA 
established differentiated limitations based on surface impoundments 
(i.e, setting BAT equal to BPT limitations for TSS).
    As part of this proposal, the EPA is not proposing a change to the 
2015 rule subcategorization of small and oil-fired boilers; therefore, 
these boilers have limitations for TSS. The EPA is incorporating and 
expanding on its previous analysis of characteristics and possible 
differences within the industry. The EPA proposes further 
subcategorization for FGD wastewater and BA transport water for boilers 
with low utilization and boilers with limited remaining useful life. In 
addition, for FGD wastewater, the EPA proposes to subcategorize units 
with high FGD flows. These proposed subcategories are discussed below.
1. Subcategory for Facilities With High FGD Flows
    The EPA is proposing to establish a new subcategory for facilities 
with high FGD flows based on the statutory factor of cost. The 2015 
rule discussed the ability of high-flow facilities to recycle FGD 
wastewater back into the air pollution control system to decrease FGD 
wastewater flows and treatment costs. After the 2015 rule, the 
Tennessee Valley Authority (TVA) submitted a request seeking a 
fundamentally different factors (FDF) variance for its Cumberland power 
facility.\52\ This variance request relied primarily on two facts. 
First, TVA stated that Cumberland's FGD wastewater flow volumes are 
several million gallons per day,\53\ approximately an order of 
magnitude higher than many other units with comparable generation 
capacity, and millions of gallons per day higher than the next highest 
flow rate in the entire industry.\54\ TVA further stated that the FGD 
system at Cumberland is constructed of a steel alloy that is 
susceptible to chloride corrosion. Based on the typical chloride 
concentrations in the FGD scrubber, the facility would be able to 
recycle little, if any, of the wastewater back to the scrubber as a 
means for reducing the flow volume sent to a treatment system.\55\ 
Second, as a result of the inability to recycle these high flows, TVA 
stated that the cost of a biological treatment system would be high.
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    \52\ Tennessee Valley Authority (TVA) --Cumberland Fossil 
Plant--NPDES Permit No. TN0005789--TVA Request for Alternative 
Effluent Limitations for Wet FGD System Discharges Based on 
Fundamentally Different Factors Pursuant to 33 U.S.C. 1311(n). April 
28, 2016.
    \53\ In the FDF variance, TVA cites to a hypothetical maximum 
flow of 9 MGD; however, based on survey responses and discussions 
with TVA staff, the company has never approached this flow rate and 
does not expect to.
    \54\ Cumberland accounts for approximately one-sixth to one-
seventh of all industry FGD wastewater flows.
    \55\ Reducing the volume purged from the FGD system or recycling 
FGD wastewater back to the FGD system can be used to reduce the 
volume of wastewater requiring treatment, and thus reduce the cost 
of treating the wastes. However, reducing the flow sent to treatment 
also has the effect of increasing the concentration of chlorides in 
the wastewater, and FGD system metallurgy can impose constraints on 
the degree of recycle that is possible.
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    The EPA proposes to subcategorize facilities with FGD purge flows 
greater than four million gallons per day, after accounting for that 
facility's ability to recycle the wastewater to the maximum limits for 
the FGD system materials of construction to avoid placing a 
disproportionate cost on such facilities.\56\ Such a flow reflects the 
reasonably predictable flow associated with actual and expected FGD 
operations.
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    \56\ Although it is theoretically possible that another coal 
facility could be built, or an FGD system installed, that resulted 
in flows of this volume, in practice, all FGD systems in the past 
decade have been built with materials that allow for recycling of 
the FGD wastewater. While facilities with these characteristics 
could potentially apply for an FDF variance, the EPA is proposing to 
subcategorize them instead because it currently has sufficient 
information to do so and because FDF variances are governed by 
strict timelines and procedural requirements set forth in 33 U.S.C. 
1311(n).
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    According to TVA's analysis, chemical precipitation plus biological 
treatment would result in a capital cost of $171 million, and an O&M 
cost of approximately $20 million per year.\57\ The EPA's cost 
estimates are even higher than TVA's (a $256 million dollar capital 
cost plus $21 million per year in O&M). These costs are five to six 
times higher than comparable costs at facilities selling similar 
numbers of MWh per year.\58\ Passing these disparately higher costs on 
to consumers would likely put the facility at a competitive 
disadvantage with other coal-fired facilities not subject to the same 
capital and operating costs. As authorized by section 304(b) of the 
CWA, which allows the EPA to consider costs, the EPA proposes a new 
subcategory for FGD wastewater based on unacceptable disparate costs. 
For such facilities, the EPA proposes to establish BAT based on 
chemical precipitation alone, with effluent limitations for mercury and 
arsenic.
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    \57\ Email to Anna Wildeman. November 13, 2018.
    \58\ This would generally also hold true for the costs of other 
FGD technology options at comparable facilities.
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2. Subcategory for Boilers With Low Utilization
    The EPA is proposing to establish a new subcategory for boilers 
with low utilization based on the statutory factors of cost and non-
water quality environmental impacts (including energy requirements). 
Low natural gas prices and other factors have led to a decline in 
capacity utilization for the majority of coal-fired boilers. According 
to EIA 923 data,\59\ overall coal-fired production for 2017 decreased 
by approximately one-third from 2009 levels, with the majority of 
boilers decreasing utilization, sometimes significantly. While the 
majority of boilers in 2009 were base load, making nameplate capacity a 
good indicator of electricity production, coal-fired boilers today 
often operate as cycling or peaking boilers, responding to changes in 
load demand.\60\
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    \59\ https://www.eia.gov/electricity/data/eia923/.
    \60\ In conversations with electric utilities, several examples 
were given of former base load facilities which have since modified 
operations to be load-following, or which no longer produce except 
for peak days in summer or winter. These discussions tracked closely 
with changes in production reported in the EIA 923 data.
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    In light of these industry changes, the EPA examined the costs of 
the proposed BAT limitations and pretreatment standards for FGD 
wastewater and BA transport water on the basis of MWh produced, rather 
than the nameplate capacity used to subcategorize boilers less than or 
equal to 50 MW in the 2015 rule. Due to changed utilization, nameplate 
capacity has become less representative of electricity production. 
Nevertheless, the EPA is not proposing any changes to the 50 MW 
nameplate capacity subcategory of the 2015 rule as that subcategory 
applied to additional wastestreams not part of this proposal (e.g., fly 
ash), and has already been implemented in some permits. Thus, the EPA 
focused on MWh production for boilers greater than 50 MW nameplate 
capacity, as discussed below.
    Similar to the EPA's finding regarding small boilers in the 2015 
rule, the record indicates that disparate costs to meet the proposed 
FGD wastewater and BA transport water BAT limitations and pretreatment 
standards are imposed on boilers with low capacity utilization. Figure 
VIII-1 below presents costs per MWh produced as measured against the 
status quo, rather than against the 2015 rule baseline. As can be seen 
in this figure, there is a significant difference between boilers above 
and below 876,000 MWh per year.\61\ As a result of

[[Page 64639]]

these disparate costs, the EPA proposes an additional subcategory for 
low capacity utilization boilers producing less than 876,000 MWh per 
year. Many of these boilers are either close to the 50 MW nameplate 
capacity of the 2015 rule (e.g., a 100 MW boiler running at 100% 
capacity), or somewhat larger units that have continued to reduce 
electricity generation due to market forces (e.g., a 400 MW boiler 
running at 25% capacity). The latter group are expected to produce 
fewer and fewer MWh per year, moving those boilers further toward the 
high $/MWh costs over time. Attempting to pass on the higher costs per 
MWh produced would make these boilers increasingly uncompetitive, 
exacerbating the disparate cost impacts.
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    \61\ This is the equivalent of a 100 MW boiler running at 100 
percent capacity or a 400 MW boiler running at 25 percent capacity.
[GRAPHIC] [TIFF OMITTED] TP22NO19.000

    In addition to  disparate costs, the EPA considered non-water 
quality environmental impacts (including energy requirements). Low 
utilization boilers tend to operate only during peak loading. Thus, 
their continued operation is useful, if not necessary, for ensuring 
electricity reliability in the near term.
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    \62\ While the EPA only presents the disparate costs of one 
technology in this figure, a similar comparison could be made for 
the technologies comprising Options 1 or 4 for a final rule. No 
comparison is necessary for Option 2 as that option already 
incorporates the subcategorization that eliminates these disparate 
costs.
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    In light of the information discussed above, the EPA proposes to 
establish a subcategory for low utilization units producing less than 
876,000 MWh per year. The EPA solicits comment on whether this 
subcategory should be based on alternative utilization thresholds. For 
this subcategory, the EPA proposes to select chemical precipitation as 
the technology basis for BAT for FGD wastewater, with effluent 
limitations for mercury and arsenic. The EPA solicits comment on 
whether chemical precipitation is appropriate and economical or if 
other approaches would be appropriate. The EPA requests commenters 
identify and include available data or information to support their 
recommended approach. Also, for this subcategory, as it did for the 
subcategories established in the 2015 rule, the EPA proposes to select 
surface impoundments as the BAT technology basis for BA transport water 
and establish limitations for TSS based on surface impoundments in 
combination with a BMP plan under section 304(e) of the Act. Although 
facilities are likely to meet these TSS limits using technologies other 
than surface impoundments once they have closed any unlined surface 
impoundments under the CCR rule, facilities may choose to retrofit a 
surface impoundment or construct a new surface impoundment. As 
authorized by section 304(b) of the CWA, which allows the EPA to 
consider costs, the EPA proposes to find that additional technologies 
are not BAT for this subcategory due to the unacceptable 
disproportionate costs per MWh those technologies would impose. 
Chemical precipitation for FGD wastewater and surface impoundments for 
BA transport water, along with a requirement to prepare and implement a 
BMP plan under section 304(e) of the Act to reduce pollutant 
discharges, are the only technologies the EPA proposes to find would 
not impose such disproportionate costs on this subcategory of boilers. 
While the Fifth Circuit in Southwestern Electric Power Company v. EPA, 
920 F.3d 999, 1018 n.20 (5th Cir. 2019), found EPA's use of surface 
impoundments as the technology basis for effluent limitations on legacy 
wastewater to be arbitrary and capricious, the Court left open the 
possibility that surface impoundments could be used as the basis for 
BAT effluent limitations so long as the Agency identifies a statutory 
factor, such as cost, in its rationale for selecting surface 
impoundments. Finally, the EPA proposes to find that allowing 
permitting authorities to set BAT limitations for BA transport water on 
a case-by-case basis using BPJ for this subcategory would be equally 
problematic. The technologies a permitting authority would necessarily 
consider are the same dry handling and high recycle rate systems that 
result in unacceptable disproportionate costs per MWh, according to the 
EPA's analysis above. The EPA solicits comment on whether the impacts 
of the proposed revisions to the CCR rule could result in a different 
analysis from the disparate

[[Page 64640]]

costs presented above. The EPA also solicits comment on other options 
to address the disproportionate impacts identified above.
3. Subcategory for Boilers Retiring by 2028
    The EPA is proposing to establish a new subcategory for boilers 
retiring by 2028 based on the statutory factors of cost, the age of the 
equipment and facilities involved, non-water quality environmental 
impacts (including energy requirements), and other factors as the 
Administrator deems appropriate. The EPA has continued to gather 
information about facility and boiler retirements, deactivations, and 
fuel conversions since the 2015 rule. Of the 107 facilities that the 
EPA identified in Section 3 of the Supplemental TDD that have 
announced, commenced or completed such actions, the most frequently 
stated reason was market forces, such as the continued low price of 
natural gas (49 facilities).\63\ This was followed by environmental 
regulations (33),\64\ consent decrees (10), and other reasons 
(46).65 66 The fact that environmental regulations were 
cited by approximately one-third of these facilities and that ELGs were 
specifically mentioned by some respondents suggests that additional 
flexibility may help to avoid premature closures for some facilities 
and/or boilers.
---------------------------------------------------------------------------

    \63\ This is consistent with recent analyses of the costs of 
coal-fired electric generation versus other sources. Examples 
include: (1) https://www.bloomberg.com/news/articles/2018-03-26/half-of-all-u-s-coal-plants-would-lose-money-without-regulation;
    (2) https://insideclimatenews.org/news/25032019/coal-energy-costs-analysis-wind-solar-power-cheaper-ohio-valley-southeast-colorado.
    \64\ Approximately 31 percent of the facilities identified 
specific environmental regulations affecting the decision-making 
process. When specific environmental regulations were stated, they 
included CPP, MATS, ELGs, CCR Rule, and Regional Haze Rules.
    \65\ Some announcements cited several rationales, hence the 
numbers do not add to 107.
    \66\ ``Other'' includes age, reliability of the facility, 
emission reductions goals, decreased local electricity demand, 
facility site limitations, and company goals to invest in clean/
renewable energy.
---------------------------------------------------------------------------

    To further explore this, the EPA examined the cost implications of 
complying with the proposed limitations and standards on a dollar-per-
MWh-produced basis under hypothetical boiler retirement scenarios. Cost 
estimates for this proposal assume that facilities will amortize 
capital and O&M costs across the 20-year life of the technologies (see 
Section 5 of the Supplemental TDD), so the EPA only examined retirement 
scenarios within the next 20 years. Furthermore, since O&M costs are 
already spread out over time, the EPA focused on capital costs, which 
also tended to make up a sizeable portion of costs in the EPA's 
estimates. Finally, the EPA looked at both three and seven percent 
discount rates. The analysis showed that a facility could be forced to 
pass on capital costs per MWh 10 to 15 times higher than those passed 
on with the assumed 20-year amortization in the EPA's cost estimates, 
and the costs per MWh remain more than double the EPA's estimates until 
amortization of six to eight years, depending on the discount rate.
    In meetings with the EPA, utilities expressed two other concerns 
related to retiring units. First, several utilities discussed the 
potential for stranded assets where equipment would be purchased near 
the end of a facility's useful life and the public utility commission 
(PUC) would not allow cost recovery. Although the utilities indicated 
that PUCs have historically allowed for cost recovery even after the 
retirement of a boiler, they provided recent examples of PUCs rejecting 
cost recovery, which make the prospect of continued recovery after 
retirement less certain. Second, the utilities expressed the need for 
sufficient time to plan, construct, and obtain necessary permits and 
approvals for replacement generating capacity. In discussions of 
example Integrated Resource Plans (IRPs) and the associated process, 
utilities suggested timelines that would extend for five to eight years 
or longer.\67\
---------------------------------------------------------------------------

    \67\ Utilities also shared instances of very quick turnaround in 
some cases.
---------------------------------------------------------------------------

    Finally, the North American Electric Reliability Corporation (NERC) 
recently conducted an aggressive stress test scenario identifying the 
reliability risks if large baseload coal and nuclear facilities were to 
bring their projected retirement dates forward.\68\ That report found 
that if these retirements happen faster than the system can respond 
(e.g., construction of new base load), significant reliability problems 
could occur. NERC cautions that, though this stress test is not a 
predictive forecast,\69\ the findings are consistent with the concern 
that electric utilities conveyed to the EPA: That the well-planned 
construction of new generation capacity and orderly retirement of older 
facilities are vital to ensuring electricity reliability.
---------------------------------------------------------------------------

    \68\ North American Electric Reliability Corporation (NERC). 
2018. Special Reliability Assessment: Generation Retirement 
Scenario. Atlanta, GA 30326. December 18. Available online at: 
https://www.nerc.com/pa/RAPA/ra/Reliability%20Assessments%20DL/NERC_Retirements_Report_2018_Final.pdf.
    \69\ ``NERC's stress-test scenario is not a prediction of future 
generation retirements nor does it evaluate how states, provinces, 
or market operators are managing this transition. Instead, the 
scenario constitutes an extreme stress-test to allow for the 
analysis and understanding of potential future reliability risks 
that could arise from an unmanaged or poorly managed transition.''
---------------------------------------------------------------------------

    In light of the information discussed above, and the EPA's 
authority under section 304(b) to consider cost, the age of equipment 
and facilities involved, non-water quality environmental impacts 
(including energy requirements), and other factors that the 
Administrator deems appropriate, the EPA proposes a new subcategory for 
boilers with a limited remaining useful life, i.e., those intending to 
close no later than December 31, 2028, subject to a certification 
requirement (described in Section XIV). For this subcategory, the EPA 
proposes to identify surface impoundments as the technology basis for 
BAT, and establish BAT limitations for TSS for both FGD wastewater and 
BA transport water. As mentioned above, the Fifth Circuit's decision in 
Southwestern Electric Power Company v. EPA left open the possibility 
that surface impoundments could be used as the basis for BAT effluent 
limitations, so long as the Agency identifies a statutory factor, such 
as cost, in its rationale for selecting surface impoundments. The EPA 
proposes to find that additional technologies such as chemical 
precipitation with or without LRTR for FGD wastewater, and the high 
recycle rate BA transport water technologies are not BAT for this 
subcategory due to the unacceptable disproportionate costs they would 
impose; the potential of such costs to accelerate retirements of 
boilers at this age of their useful life; the resulting increase in the 
risk of electricity reliability problems due to those accelerated 
retirements; and the harmonization with the CCR rule. EPA proposes to 
find that surface impoundments are the only technology that would not 
impose such disproportionate costs on this subcategory of boilers. 
Establishing surface impoundments as BAT for this subcategory would 
alleviate the choice for these facilities to either pass on disparately 
high capital costs over a shorter useful life or risk the possibility 
that post-retirement rate recovery would be denied for the significant 
capital and operating costs associated with the BAT options in this 
proposal. Creation of this subcategory would also allow electric 
utilities to continue the organized phasing out of boilers that are no 
longer economical, in favor of more efficient, newly constructed 
generating stations, and would help prevent the scenario described in 
the NERC stress test.

[[Page 64641]]

Additionally, it would ensure that facilities could make better use of 
the CCR rule's alternative closure provision, by which an unlined 
surface impoundment could continue to receive waste and complete 
closure by 2028.\70\ The EPA notes that in order to complete closure by 
2028, facilities may have to cease receiving waste well in advance of 
that date; however, a 2028 date ensures that the ELG will not restrict 
the use of this alternative closure provision regardless of when a 
facility ultimately ceases receipt of waste. Furthermore, the EPA 
proposes to find that allowing permitting authorities to set BAT 
limitations for either FGD wastewater or BA transport water on a case-
by-case basis using BPJ would be problematic. The technologies a 
permitting authority would necessarily consider are the same systems 
that result in unacceptable disproportionate costs according to the 
EPA's analysis (described above). Since these boilers are already 
nearing the end of their useful life, and are susceptible to early 
retirement, losing the ability to use surface impoundments for any 
wastewater prior to currently planned closure dates would undermine the 
flexibility of the CCR alternative closure provisions and could hasten 
the retirement of units in a manner more closely resembling the 
reliability stress test discussed above, which resulted in unacceptable 
non-water quality environmental impacts (including energy requirements) 
of compromised electric reliability.
---------------------------------------------------------------------------

    \70\ 40 CFR part 257.103(b).
---------------------------------------------------------------------------

    The EPA solicits comment on whether approaches to retirement in 
other rules have worked particularly well and might be adopted here. 
The EPA solicits comment on whether this subcategory would adversely 
incentivize coal-fired boilers planning to retire after 2028 to 
accelerate their retirement to 2028, as well as alternatives for 
addressing the disproportionate costs, energy requirements, and 
intersection with the CCR rule discussed above. The EPA also solicits 
comment on whether this subcategory should also be available for 
boilers that are planned to be repowered or replaced by 2028, not just 
those planned for retirement. For example, the EPA solicits comment on 
data and information demonstrating that boilers that are repowered with 
gas units are unable to finance both the repowering and the FGD and BA 
technology upgrades applicable to the rest of the industrial category, 
and whether BAT for such units should also be established based on 
surface impoundments as for retiring units described above. The EPA 
solicits comment on whether 2028 is the most appropriate target date 
for retirement or if a date earlier or later than 2028 would be more 
appropriate. The EPA also solicits comment on whether an additional 
subcategory for low utilization boilers retiring by a date certain that 
is after 2028 would be warranted, and what an appropriate retirement 
date might be. The EPA requests commenters identify and include 
available data or information to support their recommended approach.

D. Availability Timing of New Requirements

    Where BAT limitations in the 2015 rule are more stringent than 
previously established BPT limitations for FGD wastewater and BA 
transport water, those limitations, under the compliance dates as 
amended by the 2017 postponement rule, do not apply until a date 
determined by the permitting authority that is ``as soon as possible'' 
beginning November 1, 2020.\71\ The rule also specifies the factors 
that the permitting authority must consider in determining the ``as 
soon as possible'' date.\72\ In addition, the 2017 postponement rule 
did not revise the 2015 rule's ``no later than'' date of December 31, 
2023, for implementation because, as public commenters pointed out, 
without such a date, implementation could be substantially delayed, and 
a firm ``no later than'' date creates a more level playing field across 
the industry. As the EPA did in developing the 2015 rule, as part of 
the consideration of the technological availability and economic 
achievability of the BAT limitations in this proposal, the Agency 
considered the magnitude and complexity of process changes and new 
equipment installations that would be required at facilities to meet 
the proposed requirements. As discussed below, the EPA is considering 
availability of the technologies for FGD wastewater and BA transport 
water.
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    \71\ 40 CFR 423.11(t).
    \72\ These factors are: (a) Time to expeditiously plan 
(including to raise capital), design, procure, and install equipment 
to comply with the requirements of the final rule; (b) changes being 
made or planned at the facility in response to greenhouse gas 
regulations for new or existing fossil fuel-fired power facilities 
under the Clean Air Act, as well as regulations for the disposal of 
coal combustion residuals under subtitle D of the Resource 
Conservation and Recovery Act; (c) for FGD wastewater requirements 
only, an initial commissioning period to optimize the installed 
equipment; and (d) other factors as appropriate. 40 CFR 423.11(t).
---------------------------------------------------------------------------

    In the 2015 rule, and as amended by the 2017 postponement rule, the 
EPA selected the time frames described above to enable many facilities 
to raise needed capital, plan and design systems, procure equipment, 
and then construct and test systems. The time frames also allow for 
consideration of facility changes being made in response to other 
Agency rules affecting the steam electric power generating industry 
(e.g., the CCR rule). The EPA understands that some facilities may have 
already installed, or are now installing, technologies that could 
comply with the proposed limitations. While these facilities could 
therefore potentially comply with the proposed rule by the earliest 
date on which the limitations may become applicable (November 1, 2020), 
the EPA solicits comment on whether the earliest date on which 
facilities may have to meet the proposed limitations should be later 
than November 1, 2020.\73\
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    \73\ The EPA received a request on behalf of two Maryland 
facilities that the EPA issue a rule postponing the earliest 
compliance date from November 1, 2020 to November 1, 2022. See Feb. 
26, 2019 memorandum entitled EPA's Ongoing Reconsideration of the 
Effluent Limitation Guidelines and Standards for the Steam Electric 
Generating Point Source Category (the ``ELG Rule'' or ``the ELGs''), 
available on EPA's Docket at No. EPA-HQ-OW-2009-0819.
---------------------------------------------------------------------------

    As described previously, the industry continues to shift away from 
the use of surface impoundments for handling BA. Information collected 
since the 2015 rule, as well as conversations with electric utilities, 
EPA understands that facilities may be able to complete design, 
procurement, installation, and operation of BA transport water 
technologies by December 31, 2023.\74\ The CCR rule proposal would 
require the majority of unlined surface impoundments to stop receiving 
waste by August 2020. This would necessarily require installation by 
August 2020 of an alternative system to meet those ELG standards. As 
described earlier, because the record for the 2015 CCR rule found that 
it would be less costly for facilities to install under-boiler or 
remote drag chain systems and send BA to landfills rather than continue 
to wet sluice BA and replace unlined ponds with composite lined ponds. 
Flexibility for facilities to comply with BAT limitations for BA 
transport water beyond 2023 is not necessary because the process 
changes should already have occurred due to CCR rule requirements. 
Therefore, for BA transport water, the EPA proposes to continue the 
current timing for implementation. The EPA solicits comment on whether 
these assumptions are appropriate. The EPA also solicits comment on 
whether it should modify the existing language

[[Page 64642]]

which explicitly allows permitting authorities to consider extensions 
granted under the CCR rule in establishing compliance dates for BA 
transport water. The EPA requests commenters identify and include 
available data or information to support their recommended approach.
---------------------------------------------------------------------------

    \74\ Information in the record indicates a typical timeframe of 
15-23 months to raise capital, plan and design systems, procure 
equipment, and construct a dry handling or closed-loop or high rate 
recycle BA system.
---------------------------------------------------------------------------

    For FGD wastewater, the EPA proposes to continue the existing 
``beginning'' date, but proposes a different ``no later than'' date. 
The EPA collected updated information regarding the technical 
availability of the proposed FGD BAT technology basis, including the 
proposed VIP alternative. Based on the engineering dependency charts, 
bids, and other analytical documents in the current record, individual 
facilities may need two to three years from the effective date of any 
rule to install and begin operating a treatment system to achieve 
BAT.\75\ While three years may be appropriate for a facility on an 
individual basis, several utilities and EPC firms pointed out 
difficulties in retrofitting on a company-wide or industry-wide basis. 
Moreover, the same engineers, vendors, and construction companies are 
often used across facilities. As was the case with BA transport water 
above, facilities with FGD wastewater have continued to convert away 
from surface impoundments, and the majority of facilities with unlined 
surface impoundments would have to stop receiving waste in those 
unlined surface impoundments by August 2020, under the CCR proposal. To 
stop receiving waste in an unlined surface impoundment, a facility 
would need to construct a treatment system to meet applicable ELGs, 
such as a tank-based system that meets the BPT limitations. However, 
biological treatment is not necessary to remove TSS, and therefore more 
time for implementation of the proposed BAT limitations will help to 
accommodate the process changes necessitated by combining chemical 
precipitation and LRTR, and alleviate competition for resources. 
Considering all the factors described above, the EPA proposes to extend 
the ``no later than'' date for compliance with BAT FGD wastewater 
limitations to December 31, 2025, based on the proposed technology 
basis. Thus, for FGD wastewater, where BAT limitations are more 
stringent than previously established BPT limitations, BAT limitations 
would not apply until a date determined by the permitting authority 
that is as soon as possible beginning November 1, 2020, but no later 
than December 31, 2025. The EPA solicits comment on whether these 
assumptions are appropriate and whether these compliance dates should 
be harmonized with the compliance dates for BA transport water. The EPA 
requests commenters identify and include available data or information 
to support their recommended approach.
---------------------------------------------------------------------------

    \75\ Information in the record indicates a typical time frame of 
26 to 34 months to raise capital, plan and design systems (including 
any necessary pilot testing), procure equipment, and construct and 
then test systems (including a commissioning period for FGD 
wastewater treatment systems). Many facilities have already 
completed initial steps of this process, having evaluated water 
balances and conducted pilot testing to prepare for implementing the 
2015 rule.
---------------------------------------------------------------------------

    In addition, as discussed earlier, the EPA is proposing to give 
facilities that elect to use the VIP until December 31, 2028, to meet 
the VIP limitations, which are based on membrane filtration technology. 
That is the date on which the EPA proposes to determine that the 
membrane filtration-based limitations are ``available'' (as that term 
is used in the CWA) to all plants that might choose to participate in 
the voluntary incentives program. The EPA is proposing to give 
facilities sufficient time to work out operational issues related to 
being the first facilities in the U.S. to treat FGD wastewater using 
membrane filtration at full scale, as well as having to dispose of the 
resulting brine. Both issues contribute to the EPA's proposed decision 
that membrane filtration is not BAT on a nationwide basis at this time. 
The EPA also wants to incentivize facilities to opt into a program that 
can achieve significant pollutant reductions.

E. Regulatory Sub-Options To Address Bromides

    The 2015 rule rejected thermal evaporation technology as the basis 
for BAT and therefore did not establish limitations for bromides in FGD 
wastewater. Section XVI.D of the preamble noted that the VIP 
established in the 2015 rule would address bromide through the 
limitations for TDS. The newly proposed VIP includes limits for 
bromide. Because the EPA proposes to provide more flexible VIP limits 
on other pollutants and more flexible VIP timing, the EPA estimates 
that selecting the proposed VIP may be the least-cost option for some 
facilities. The facilities that the EPA estimates VIP may be the least-
cost option range in FGD wastewater flows, nameplate capacity, capacity 
utilization, and location. The EPA cost estimates for the VIP tend to 
be lower at facilities where no treatment has been installed beyond 
surface impoundments, however even for this group of facilities 
biological systems are still often least-cost. Thus, while the EPA 
estimates that the proposed revisions to the VIP may address bromide at 
more facilities than the 2015 VIP, it is still a voluntary program, and 
concerns about costs, availability, and disposal of the resultant brine 
are still present.
    The EPA suggested in the preamble to the 2015 rule that water-
quality-based effluent limitations may be appropriate on a site-
specific basis to address the potential impacts of bromides on 
downstream drinking water treatment facilities, as determined by state 
permitting authorities. Since that time, few states have begun to 
monitor bromide discharges and it is unclear how many have acted to 
address such discharges.\76\
---------------------------------------------------------------------------

    \76\ The EPA is aware that Pennsylvania, Alabama, and North 
Carolina conduct bromide monitoring at multiple facilities with FGD 
discharges.
---------------------------------------------------------------------------

    On June 8, 2018, drinking water utilities sent a letter to the EPA 
requesting that the Agency consider three regulatory BAT/PSES 
technology options to reduce bromide discharges in FGD wastewater: (1) 
Zero liquid discharge technologies (ZLD), such as membrane filtration 
or thermal treatment; (2) treatment with reverse osmosis; or (3) a 
requirement that facilities provide data to the state permitting 
authority for use in calculating a site-specific discharge limitation. 
For the reasons explained earlier in this section, the EPA is not 
proposing to base BAT limitations or PSES for FGD wastewater at all 
existing units based on membrane filtration or thermal treatment. The 
EPA proposes a water quality-based approach as the most appropriate 
approach and solicits comment on that alternative, including ways that 
such an alternative could be strengthened. However, in light of the 
letter from the drinking water utilities and the limited state action 
since the 2015 rule to address this potential issue, the EPA is 
requesting comment on three bromide-specific regulatory sub-options in 
addition to the proposed approach of retaining the 2015 rule's approach 
of leaving bromides to be limited by permitting authorities where 
appropriate using water quality-based effluent limitations: \77\ (1) A 
monitoring requirement under CWA section 308; (2) a bromide 
minimization plan using narrative or non-numeric limitations under CWA 
sections 301(b) and 304(b); or (3) a numeric limit under CWA sections 
301(b) and 304(b) based on product substitution. Each of these are 
described in more detail below.
---------------------------------------------------------------------------

    \77\ These sub-options would not be applicable to the VIP 
limitations as those limitations would control bromide (and other 
halogens) in FGD wastewater discharges.

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[[Page 64643]]

    In the case of FGD wastewater monitoring, the EPA solicits comment 
on two approaches suggested by electric utilities. Under the first 
approach, bromide would be monitored monthly for two years, and 
thereafter only after specific changes in facility operations that 
could alter bromide concentrations in FGD wastewater. Such operational 
changes could include changing to a brominated refined coal, a bromide 
addition process, a coal feedstock with higher bromide levels, or use 
of brominated powdered activated carbon (PAC). Under the second 
approach, bromide would be monitored monthly for five years in two 
locations to better capture bromide variability. The first monitoring 
location would be of intake water not affected by the site's discharge 
to capture what fraction of bromide is present from background surface 
water. The second would be of discharge water to capture the amount of 
bromide added by various wastewaters. The monitoring point for the FGD 
wastewater discharge could be at the final outfall. The EPA also 
solicits comment on whether monitoring should be longer or shorter 
duration than proposed and if additional monitoring locations may be 
appropriate to capture other operational changes that the EPA has not 
identified.
    The EPA solicits comment on whether a facility should develop a 
plan to minimize its use of bromide on a site-specific basis. Such a 
plan could allow a facility to consider the costs of potential 
approaches to minimizing bromide use in conjunction with its efforts to 
meet other standards (e.g., MATS). Otherwise, facilities would minimize 
the bromide in their discharges by switching to lower-bromide coals, 
reducing bromide addition, and/or cutting back on refined coal use. The 
EPA solicits comment on whether such a plan is appropriate for all 
steam electric generators and, if so, the elements that might be 
included in such a plan.
    Regarding a bromide limitation based on product substitution, the 
EPA solicits comment on whether a limitation could be established that 
reflects the difference in concentrations naturally occurring in coal 
as opposed to levels found in refined coal or from other halogen 
applications. Alternatively, the EPA solicits comment on whether 
facilities could certify that they do not burn refined coal and/or use 
bromide addition processes. The EPA solicits data that supports 
development of a numerical bromide limitation, or that demonstrates a 
specific numerical bromide limitation to be inappropriate.
    The Agency solicits input on the pros and cons of each of these 
bromide sub-option approaches. Finally, the Agency solicits comment on 
other pollutants, including other halides, discharged from steam 
electric facilities that may impact the formation of disinfection 
byproducts (DBPs).

F. Economic Achievability

    As the EPA did for the 2015 rule, the Agency performed cost and 
economic impact assessments using the Integrated Planning Model (IPM) 
to determine the effect of the proposed ELGs, using a baseline that 
incorporates impacts from other relevant environmental regulations (see 
Chapter 5 in RIA). At the time of the 2015 rule, the IPM model showed a 
total incremental closure of 843 MW of coal-fired generation as a 
result of the ELGs, corresponding to a net effect of two boiler 
closures.\78\ However, since that time, natural gas prices have 
remained low, additional coal facilities have retired or refueled, and 
changes that have been proposed to several environmental regulations 
have been included in those model runs. Due to these changes, the EPA 
ran an updated version of IPM. (See Section VIII.C.2 for additional 
discussion on these updates.) This update showed that the 2015 rule 
resulted in the closure of 1.8 GW of coal-fired generation, 
corresponding to a net effect of approximately four boiler closures, 
based on the average capacity of coal-fired electric boilers.
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    \78\ In meetings with EPA since the 2015 rule, electric 
utilities have expressed concerns that IPM underpredicts closures by 
not accounting for the ability of facilities in regulated states to 
cost recover even if they would otherwise lose money or are not 
economical to operate.
---------------------------------------------------------------------------

    The EPA similarly ran the IPM model to determine the effect of the 
regulatory options presented in Table VII-1. Options 2 and 4 bound the 
costs to industry of these four options, IPM results from these options 
alone reflect the range of impacts associated with all four regulatory 
options.\79\ The IPM models for these two options were run prior to 
finalization of the ACE rule (the impact of ACE is analyzed in a 
separate sensitivity scenario) and ranged from a total net increase of 
0.7 GW to 1.1 GW in coal-fired generating capacity compared to the 2015 
rule, reflecting full compliance by all facilities. This capacity 
increase corresponds to a net effect of one to two boiler closures 
avoided as a result of this reconsideration action. These IPM results 
indicate that the proposed Option 2 is economically achievable for the 
steam electric power generating industry as a whole, as required by CWA 
section 301(b)(2)(A). Following the promulgation of the ACE rule, the 
EPA also conducted a sensitivity analysis that includes the effects of 
that rule in the ELG analytic baseline. The results of this sensitivity 
analysis, which are detailed in Appendix C of the RIA, also indicate 
that the proposed Option 2 is economically achievable. The EPA will use 
the latest IPM baseline, including the ACE rule as part of existing 
regulations, when analyzing the ELG final rulemaking.
---------------------------------------------------------------------------

    \79\ Although Option 1 includes the less stringent chemical 
precipitation technology, Option 2 has a greater savings due to 
subcategorization of low utilization boilers.
---------------------------------------------------------------------------

    The EPA's economic achievability analysis for this and other 
options is described in Section VIII, below.

G. Non-Water Quality Environmental Impacts

    For the 2015 rule, the EPA performed an assessment of non-water 
quality environmental impacts, including energy requirements, air 
impacts, solid waste impacts, and changes in water use and found them 
to be acceptable. The EPA has reevaluated these impacts in light of the 
changed industry profile, as well as the proposed changes to BAT. Based 
on the results of these analyses the EPA determined that Options 1, 2, 
and 3 have acceptable non-water quality impacts. Option 4, however, 
would result in unacceptable non-water quality environmental impacts 
where management of the brine could divert FA that might otherwise be 
sold for use in products (e.g., replacing Portland cement in concrete) 
back toward placement in a landfill. See additional information in 
Section 7 of the Supplemental TDD, as well as Section X of this 
preamble.

H. Impacts on Residential Electricity Prices and Low-Income and 
Minority Populations

    As the EPA did for the 2015 rule, the Agency examined the effects 
of today's regulatory options on consumers as an additional factor that 
might be appropriate when considering what level of control represents 
BAT. If all annualized compliance cost savings were passed on to 
residential consumers of electricity, instead of being borne by the 
operators and owners of facilities, the average monthly cost savings 
under any of the options would be between $0.01 and 0.04 per month as 
compared to the 2015 rule.
    The EPA similarly evaluated the effect of today's regulatory 
options on minority and low-income populations. As explained in Section 
XII, the EPA used demographic data for populations potentially impacted 
by steam electric power plant discharges due to their proximity (i.e., 
within 50 miles) to one

[[Page 64644]]

or more plants. For those populations, the EPA evaluated both 
recreational and subsistence fisher populations. The analysis described 
in Section XII indicates that absolute changes in human health impacts 
are smaller than the overall impacts resulting from the 2015 rule. 
However, low-income and minority populations are potentially affected 
to a greater degree than the general population by discharges from 
steam electric facilities and are expected to also accrue to a greater 
degree than the general population the benefits of the proposed rule, 
positive or negative.

I. Additional Rationale for the Proposed PSES

    The EPA is continuing to rely on the pass-through analysis as the 
basis of the limitations and standards in the 2015 rule. With respect 
to FGD wastewater, as discussed above, the long-term averages for low 
residence time biological treatment are very similar to or lower than 
those achieved with high residence time biological systems. On this 
basis, the EPA proposes to conclude that mercury, arsenic, selenium, 
and nitrate/nitrite pass-through POTWs, as it concluded in the 2015 
rule.
    With respect to BA, the EPA notes that facilities converting to dry 
handling or recycling all of their BA transport water would continue to 
perform as the zero discharge systems the EPA used in its 2015 rule 
pass-through analysis. As explained in Section VII.b.ii, for those 
facilities using high rate recycle systems, the EPA proposes to allow a 
discharge up to 10 percent of the system volume per day on a 30-day 
rolling average and to subject such direct discharges to TSS 
limitations of BPT. Consistent with the 2015 rule pass through 
analysis, TSS is not considered to pass through and the EPA would not 
establish TSS limitations under PSES.
    Thus, like BAT, the EPA proposes to establish PSES based on Option 
2: PSES for FGD wastewater based on chemical precipitation plus low 
hydraulic residence time biological treatment, and PSES for BA 
transport water based on dry handling or high recycle rate systems.\80\ 
The EPA proposes these technologies as the bases for PSES for the same 
reasons that the EPA proposes the technologies as the bases for BAT, 
and also proposes the same subcategories proposed for BAT.\81\
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    \80\ Only two facilities currently discharge BA transport water 
to POTWs, and EPA believes that both facilities qualify for the 
proposed subcategorization for low utilization boilers. Thus, this 
PSES may ultimately not apply to any facilities.
    \81\ Where any of the subcategories would establish BAT based on 
surface impoundments, with a restriction on TSS, there would be no 
such parallel restriction for the analogous PSES subcategory because 
POTWs effectively treat TSS.
---------------------------------------------------------------------------

    As with the final BAT effluent limitations, in considering the 
availability and achievability of the final PSES, the EPA concluded 
that existing indirect dischargers need some time to achieve the final 
standards, in part to avoid forced outages (see Section VIII.C.7). 
However, in contrast to the BAT limitations (which apply on a date 
determined by the permitting authority that is as soon as possible 
beginning November 1, 2020, but no later than December 31, 2023, for BA 
transport water, and no later than December 31, 2025, for FGD 
wastewater), facilities must meet the PSES no later than three years 
after the effective date of any final rule. Under CWA section 
307(b)(1), pretreatment standards shall specify a time for compliance 
not to exceed three years from the date of promulgation, so the EPA 
cannot establish a longer implementation period. Moreover, unlike 
limitations on direct discharges, limitations on indirect discharges 
are not implemented through an NPDES permit and thus are specified 
clearly for the discharger without delay, without waiting some time for 
the next permit issuance. The EPA has determined that all current 
indirect dischargers can meet the standards within three years of the 
effective date of any final rule (which the EPA projects will be issued 
in the summer of 2020).

VIII. Costs, Economic Achievability, and Other Economic Impacts

    The EPA evaluated the costs and associated impacts of the proposed 
regulatory options on existing boilers at steam electric facilities. 
These costs are analyzed within the context of compounding regulations 
and other industry trends that have affected steam electric facilities 
profitability and generation. These include the impacts of existing 
environmental regulations (e.g., Cross-State Air Pollution Rule, 
Mercury and Air Toxics Standards, CWA section 316(b) rule, final CCR 
rule, final ACE rule), as well as other market conditions described in 
Section V.B.\82\ This section provides an overview of the methodology 
the EPA used to assess the costs and the economic impacts and 
summarizes the results of these analyses. See the RIA in the docket for 
additional detail.
---------------------------------------------------------------------------

    \82\ As discussed above, impacts of the final ACE rule will be 
incorporated into this analysis after proposal, but were not 
included here as the analyses for these proposed ELGs were completed 
prior to the ACE rule being finalized.
---------------------------------------------------------------------------

    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 on the 
industry as a whole, which typically includes an assessment of 
incremental facility closures attributable to a regulatory option. As 
described in more detail below, this proposed ELG is expected to 
provide cost savings when compared to the baseline. Like the prior 
analysis of the 2015 rule, the cost and economic impact analysis for 
this proposed rulemaking focuses on understanding the magnitude and 
distribution of compliance cost savings across the industry, and the 
broader market impacts.
    The EPA used certain indicators to assess the impacts of the 
proposed regulatory options on the steam electric power generating 
industry as a whole. These indicators are consistent with those used to 
assess the economic achievability of the 2015 rule (80 FR 67838); 
however, for this proposal, the EPA compared the values to a baseline 
that reflects implementation of existing environmental regulations (as 
of this proposal), including the 2015 rule. In the 2015 rule analysis, 
the costs of achieving the 2015 rule requirements were reflected in the 
policy cases analyzed rather than the baseline. Here, the baseline 
appropriately includes costs for achieving the 2015 rule limitations 
and standards, and the policy cases show the impacts resulting from 
changes to those existing 2015 limitations and standards. More 
specifically, the EPA considered the total cost to industry and change 
in the number and capacity of specific boilers and facilities expected 
to close under the options in this proposal (including proposed Option 
2) compared to the estimated baseline costs. The EPA also analyzed the 
ratio of compliance costs to revenue to see how the proposed regulatory 
options change the number of facilities and their owning entities that 
exceed certain thresholds indicating potential financial strain.
    In addition to the analyses supporting the economic achievability 
of the regulatory options, the EPA conducted other analyses to (1) 
characterize other potential impacts of the regulatory options (e.g., 
on electricity rates), and (2) to meet the requirements of Executive 
Orders or other statutes (e.g., Executive Order 12866, Regulatory 
Flexibility Act, Unfunded Mandates Reform Act).

A. Facility-Specific and Industry Total Costs

    The EPA estimated facility-specific costs to control FGD wastewater 
and BA transport water discharges at existing boilers at steam electric 
facilities to

[[Page 64645]]

which the ELGs apply.\83\ The EPA assessed the operations and treatment 
system components currently in place at a given unit (or expected to be 
in place as a result of other existing environmental regulations), 
identified equipment and process changes that facilities would likely 
make to meet the 2015 rule (for baseline) and each of the four 
regulatory options presented in Table VII-1, and estimated the cost to 
implement those changes. As explained in the Supplemental TDD, the 
baseline also accounts for additional announced unit retirements, 
conversions, and relevant operational changes that have occurred since 
the EPA promulgated the 2015 rule. The EPA thus derived facility-level 
capital and O&M costs for controlling FGD wastewater and BA transport 
water using the technologies that form the bases of the 2015 rule, and 
for each regulatory option presented in Table VII-1 for existing 
sources. See Section 5 of the Supplemental TDD for a more detailed 
description of the methodology the EPA used to estimate facility-level 
costs for this proposal.
---------------------------------------------------------------------------

    \83\ The EPA did not estimate costs for other wastestreams not 
in this proposal.
---------------------------------------------------------------------------

    Following the same methodology used for the 2015 rule analysis, the 
EPA used a rate of seven percent to annualize one-time costs and costs 
recurring on other than on an annual basis over a specific useful life, 
implementation, and/or event recurrence period. For capital costs and 
initial one-time costs, the EPA used 20 years. For O&M costs incurred 
at intervals greater than one year, EPA used the interval as the 
annualization period (3 years, 5 years, 6 years, 10 years). The EPA 
added annualized capital, initial one-time costs, and the non-annual 
portion of O&M costs to annual O&M costs to derive total annualized 
facility costs. The EPA then calculated total industry costs by summing 
facility-specific annualized costs. 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 facilities and 
incorporate approximate capital depreciation and other relevant tax 
treatments in the analysis. The EPA uses pre- and/or after-tax costs in 
different analyses, depending on the concept appropriate to each 
analysis (e.g., social costs are calculated using pre-tax costs whereas 
cost-to-revenue screening-level analyses are conducted using after-tax 
costs).
    Table VIII-1 summarizes estimates of incremental pre- and post-tax 
industry costs for the four regulatory options presented in Table VII-1 
as compared to the baseline. All four options provide cost savings 
(negative incremental costs) as compared to the costs that the industry 
would incur under the 2015 rule. Under all four options, some savings 
are attributable to cheaper high recycle rate BA systems. Under Options 
1, 2, and 3, additional savings are due to lower cost FGD wastewater 
treatment systems (chemical precipitation and LRTR). Under Option 2, 
further savings are attributable to the subcategorization of low 
utilization boilers. Finally, some cost savings are due to the changes 
in compliance timeframes discussed above in Section VII.D. The after-
tax savings range from approximately $26 million under Option 4 to $147 
million under Option 2.\84\
---------------------------------------------------------------------------

    \84\ In response to additional information the EPA received from 
a vendor showing installed costs of LRTR were lower than EPA's 
predicted costs, and to account for the small difference in cost 
between the sand filter and ultrafiltration polishing stage 
technologies, the EPA conducted a sensitivity analysis (DCN 
SE07120). Based on this analysis, the costs to install LRTR may be 
approximately five percent lower than the LRTR cost estimates used 
for developing the total costs presented in Table VIII-1.

         Table VIII-1--Estimated Total Annualized Industry Costs
             [Million of 2018$, seven percent discount rate]
------------------------------------------------------------------------
              Regulatory  option                  Pre-tax     After-tax
------------------------------------------------------------------------
Option 1......................................      -$165.6      -$136.6
Option 2......................................       -175.6       -146.5
Option 3......................................       -126.3       -105.9
Option 4......................................        -25.5        -26.4
------------------------------------------------------------------------

B. Social Costs

    Social costs are the costs of the proposed rule from the viewpoint 
of society as a whole, rather than the viewpoint of regulated 
facilities (which are private costs). In calculating social costs, the 
EPA tabulated the pre-tax costs in the year when they are estimated to 
be incurred. As described in Section VII.D of this preamble, the 
proposed compliance deadlines and therefore the expected technology 
implementation years vary across the regulatory options. The EPA 
performed the social cost analysis over a 27-year analysis period of 
2021-2047, which combines the length of the period during which 
facilities are anticipated to install the control technologies (which 
could be as late as 2028 under Option 4) and the useful life of the 
longest-lived technology installed at any facility (20 years). The EPA 
calculated the social cost of the proposed rule using both a three 
percent discount rate and an alternative discount rate of seven 
percent.
    Social costs include costs incurred by both private entities and 
the government (e.g., in implementing the regulation). As described 
further in Chapter 10 of the RIA, the EPA did not evaluate the 
incremental increase in the cost to state governments to evaluate and 
incorporate BPJ into NPDES permits. EPA solicits comments on whether 
these incremental costs are significant enough to be included. 
Consequently, the only category of costs used to calculate social costs 
are those pre-tax costs estimated for steam electric facilities. Note 
that the annualized social costs presented in Table VIII-2 for the 
seven percent discount rate differ from comparable pre-tax industry 
compliance costs shown in Table VIII-1. The costs in TableVIII-1 
represent the annualized costs of each option if they were incurred in 
2020, whereas the annualized costs in Table VIII-2 are estimated based 
on the stream of future costs starting in the year that individual 
facilities are projected to actually comply with the requirements of 
the proposed options under the availability timing proposed in Section 
VII.D.
    Table VIII-2 presents the total annualized social costs of the four 
regulatory options presented in Table VII-1, compared to the baseline 
and calculated using three percent and seven percent discount rates. 
All four options provide cost savings (negative incremental costs) 
compared to the baseline using a seven percent discount rate, and 
Options 1, 2, and 3 also show cost savings using a three percent 
discount rate. Option 2 has estimated annualized cost savings of $166.2 
million using a seven percent discount rate and $136.3 million using a 
three percent discount rate.

          Table VIII-2--Estimated Total Annualized Social Costs
        [Million of 2018$, three and seven percent discount rate]
------------------------------------------------------------------------
                                                3% Discount  7% Discount
              Regulatory  option                    rate         rate
------------------------------------------------------------------------
Option 1......................................      -$130.6      -$154.0
Option 2......................................       -136.3       -166.2
Option 3......................................        -90.1       -119.5
Option 4......................................         11.9        -27.3
------------------------------------------------------------------------

C. Economic Impacts

    The EPA assessed the economic impacts of this proposed rule in two 
ways: (1) A screening-level assessment of the cost impacts on existing 
boilers at steam electric facilities and the entities

[[Page 64646]]

that own those facilities, based on comparison of costs to revenue; and 
(2) an assessment of the impact of the regulatory options presented in 
Table VII-1 within the context of the broader electricity market, which 
includes an assessment of changes in predicted facility closures 
attributable to the options. The following sections summarize the 
results of these analyses. The RIA discusses the methods and results in 
greater detail.
    The first set of cost and economic impact analyses--at both the 
facility and parent company levels--provide screening-level indicators 
of the impacts of costs for FGD wastewater and BA transport water 
controls relative to historical operating characteristics of steam 
electric facilities incurring those costs (i.e., level of electricity 
generation and revenue). The EPA conducted these analyses for the 
baseline and for the four regulatory options presented in Table VII-1, 
and then compared these impacts to understand the incremental effects 
of the regulatory options in this proposal. The second set of analyses 
look at broader electricity market impacts considering the 
interconnection of regional and national electricity markets. It also 
looks at the distribution of impacts at the facility and boiler level. 
This second set of analyses provides insight on the impacts of the 
regulatory options in this proposal on steam electric facilities, as 
well as the electricity market as a whole, including changes in 
generation capacity, generation, and wholesale electricity prices. The 
market analysis compares model predictions for the options to a base 
case that includes the predicted and observed economic and market 
effects of the 2015 rule. The EPA used results from the screening 
analysis of facility- and entity-level impacts, together with changes 
in projected capacity closure from the market model, to understand the 
impacts of the regulatory options in this proposal relative to the 
baseline.
1. Screening-Level Assessment
    The EPA conducted a screening-level analysis of each regulatory 
option's potential impact to existing boilers at steam electric 
facilities and parent entities based on cost-to-revenue ratios. For 
each of the two levels of analysis (facility and parent entity), the 
Agency assumed, for analytic convenience and as a worst-case scenario, 
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 facilities and their parent entities. This assumption 
overstates the impacts of compliance expenditures since steam electric 
facilities that operate in a regulated market may be able to pass on 
changes in production costs to consumers through changes in electricity 
prices. It is, however, an appropriate assumption for a screening-level 
estimate of the potential cost impacts.
a. Facility-Level Cost-to-Revenue Analysis
    The EPA developed revenue estimates for this analysis using EIA 
data. The EPA then calculated the change in the annualized after-tax 
costs of the four regulatory options presented in Table VII-1 as a 
percent of baseline annual revenues. See Chapter 4 of the RIA for a 
more detailed discussion of the methodology used for the facility-level 
cost-to-revenue analysis.
    Cost-to-revenue ratios are used to describe impacts to entities 
because they provide screening-level indicators of potential economic 
impacts. Just as for the facilities owned by small entities under 
guidance in U.S. EPA (2006),\85\ the full range of facilities incurring 
costs below one percent of revenue are unlikely to face economic 
impacts, while facilities with costs between one percent and three 
percent of revenue have a higher chance of facing economic impacts, and 
facilities incurring costs above three percent of revenue have a still 
higher probability of economic impacts.
---------------------------------------------------------------------------

    \85\ U.S. EPA (Environmental Protection Agency). 2006. EPA's 
Action Development Process: Final Guidance for EPA Rulewriters: 
Regulatory Flexibility Act as amended by the Small Business 
Regulatory Enforcement Fairness Act. November 2006. Available online 
at: https://www.epa.gov/reg-flex/epas-action-development-process-final-guidance-epa-rulewriters-regulatory-flexibility-act.
---------------------------------------------------------------------------

    As a result of the 2015 rule (baseline), the EPA estimated that 18 
facilities incur costs greater than or equal to one percent of revenue, 
including six facilities that have costs greater than or equal to three 
percent of revenue, and an additional 96 facilities incur costs that 
are less than one percent of revenue. By contrast, the four regulatory 
options the EPA analyzed for this proposal are estimated to provide 
cost savings that reduce this impact to various degrees, with Option 2 
showing the largest reductions in cost. Options 1, 3, and 4 show an 
estimated 16 to 19 facilities with costs greater than or equal to one 
percent of revenue, including four or five facilities with costs 
greater than or equal to three percent of revenue. Under Option 2, the 
EPA estimated that eight facilities incur costs greater than or equal 
to one percent of revenue, including two facilities that have costs 
greater than or equal to three percent of revenue, and an additional 
100 facilities incur costs that are less than one percent of revenue.
b. Parent Entity-Level Cost-to-Revenue Analysis
    The EPA also assessed the economic impact of the regulatory options 
presented in Table VII-1 at the parent entity level. The screening-
level cost-to-revenue analysis at the parent entity level provides 
insight on the impact on those entities that own existing boilers at 
steam electric facilities. In this analysis, the domestic parent entity 
associated with a given facility is defined as that entity with the 
largest ownership share in the facility. For each parent entity, the 
EPA compared the incremental change in the total annualized after-tax 
costs and the total revenue for the entity compared to the baseline 
(see Chapter 4 of the RIA for details). Following the methodology 
employed in the analyses for the 2015 rule (80 FR 67838), the EPA 
considered a range of estimates for the number of entities owning an 
existing boiler at a steam electric power facility to account for 
partial information available for steam electric facilities that are 
not expected to incur ELG compliance costs.
    Similar to the facility-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 boilers at steam electric facilities 
ranges from 243 (lower-bound estimate) to 478 (upper-bound estimate), 
depending on the assumed ownership structure of facilities not 
incurring ELG costs and not explicitly analyzed. The EPA estimates that 
in the baseline 236 to 470 parent entities, respectively, would either 
incur no costs or the annualized cost they incur to meet the 2015 rule 
BAT limitations and pretreatment standards would represent less than 
one percent of their revenues.
    Compared to the baseline, all four regulatory options reduce the 
impacts on the small number of entities incurring costs. The changes 
are greatest for Option 2, which has five fewer entities with costs 
exceeding one percent of revenue, including one less entity with costs 
exceeding three percent of revenue, with the remaining entities either 
having no cost, or costs that are less than one percent of revenue. 
Options 1 and 3 each have two fewer entities in the one to three 
percent of revenue category, and Option 4 has

[[Page 64647]]

one fewer entity in the one to three percent of revenue category.
2. Electricity Market Impacts
    In analyzing the impacts of regulatory actions affecting the 
electric power sector, the EPA used IPM, a comprehensive electricity 
market optimization model that can evaluate such impacts within the 
context of regional and national electricity markets. The model is 
designed to evaluate the effects of changes in boiler-level electric 
generation costs on the total cost of electricity supply, subject to 
specified demand and emissions constraints. Use of a comprehensive, 
market analysis system is important in assessing the potential impact 
of any power facility regulation because of the interdependence of 
electric boilers in supplying power to the electric transmission grid. 
Changes in electricity production costs at some boilers can have a 
range of broader market impacts affecting other boilers, including the 
likelihood that various units are dispatched, on average. The analysis 
also provides important insight on steam electric capacity closures 
(e.g., retirements of boilers that become uneconomical relative to 
other boilers), or avoided closures, based on a more detailed analysis 
of market factors than in the screening-level analyses above. The 
results further inform the EPA's understanding of the potential impacts 
of the regulatory options presented in Table VII-1. For the current 
analyses, the EPA used version 6 (V6) of IPM to analyze the impacts of 
the regulatory options. IPM V6 is based on an inventory of U.S. 
utility- and non-utility-owned boilers and generators that provide 
power to the integrated electric transmission grid, including 
facilities to which the ELGs apply. IPM V6 embeds an energy demand 
forecast that is derived from DOE's ``Annual Energy Outlook 2018'' (AEO 
2018). IPM V6 also incorporates the expected compliance response to 
existing regulatory requirements for regulations affecting the power 
sector (e.g., Cross-State Air Pollution Rule (CSAPR) and CSAPR Update 
Rule, Mercury and Air Toxics Rule (MATS), the Cooling Water Intake 
Structure (CWIS) rule, and 2015 CCR rule, as well as the 2015 rule). 
Federal CO2 standards for existing sources are not modeled 
in IPM V6, owing to ongoing litigation.
    The EPA analyzed proposed Option 2 and Option 4 using IPM V6. As 
discussed in Section VIII.A, these two options have the greatest and 
least cost savings, respectively, compared to the baseline, and 
therefore reflect the full range of potential impacts from the 
regulatory options in this proposal. In addition, following 
promulgation of the ACE final rule, EPA also analyzed proposed Option 2 
relative to a baseline that includes the ACE rule. See Appendix C in 
the RIA for details of these results.
    In contrast to the screening-level analyses, which are static 
analyses and do not account for interdependence of electric boilers in 
supplying power to the electricity transmission grid, IPM V6 accounts 
for potential changes in the generation profile of steam electric and 
other boilers and consequent changes in market-level generation costs, 
as the electric power market responds to changes in generation costs 
for steam electric boilers due to the regulatory options. Additionally, 
in contrast to the screening-level analyses, in which the EPA assumed 
no cost pass through of ELG compliance costs, IPM V6 depicts production 
activity in wholesale electricity markets where the specific increases 
in electricity prices for individual markets would result in some 
recovery of compliance costs for plants in those markets.
    In analyzing the regulatory options presented in Table VII-1, the 
EPA estimated changes in fixed and variable costs for the steam 
electric facilities and boilers already incurring costs in the baseline 
to instead incur costs (or avoid incurring costs) to comply with Option 
2 and Option 4. Because IPM is not designed to endogenously model the 
selection of wastewater treatment technologies as a function of 
electricity generation, effluent flows, and pollutant discharge, the 
EPA estimated these costs exogenously for each steam electric 
generating unit and input these costs into the IPM model as fixed and 
variable O&M cost adders. The EPA then ran IPM V6 including these new 
cost estimates to determine the dispatch of electric boilers that would 
meet projected demand at the lowest costs, subject to the same 
constraints as those present in the baseline analysis. The estimated 
changes in facility- and boiler-specific production levels and costs--
and, in turn, changes in total electric power sector costs and 
production profile--are key data elements in evaluating the expected 
national and regional effects of the regulatory options in this 
proposal, including closures or avoided closures of steam electric 
boilers and facilities. The EPA considered impact metrics of interest 
at three levels of aggregation: (1) Impact on national and regional 
electricity markets (all electric power generation, including steam and 
non-steam electric facilities); (2) impact on steam electric facilities 
as a group, and (3) impact on individual steam electric facilities 
incurring costs. Chapter 5 of the RIA discusses the first analysis; the 
sections below summarize the last two, which are further described in 
Chapter 5 and in Appendix C of the RIA. All results presented below are 
representative of modeled market conditions in the years 2028-2033, 
when the rule would either be implemented or plans for implementation 
by the end of 2028 would be well underway at all facilities.
a. Impacts on Existing Steam Electric Facilities
    The EPA used IPM V6 results for 2030 \86\ to assess the potential 
impact of the regulatory options presented in Table VII-1 on existing 
boilers at steam electric facilities. The purpose of this analysis is 
to assess any fleetwide changes from baseline impacts on boilers at 
steam electric facilities. Table VIII-3 reports estimated results for 
existing boilers at steam electric facilities, as a group. The EPA 
looked at the following metrics: (1) Incremental (and avoided) early 
retirements and capacity closures, calculated as the difference between 
capacity under the regulatory option and capacity under the baseline; 
(2) incremental capacity closures as a percentage of baseline capacity; 
(3) change in electricity generation from facilities regulated by ELGs; 
(4) changes in variable production costs per MWh, calculated as the sum 
of total fuel and variable O&M costs divided by net generation; and (5) 
changes in annual costs (fuel, variable O&M, fixed O&M, and capital). 
Note that changes in electricity generation presented in Table VIII-3 
are attributable both to changes in retirements, as well as changes in 
capacity utilization at boilers and plants whose retirement status does 
not change.
---------------------------------------------------------------------------

    \86\ IPM model year 2030 represents years 2028-2033.

[[Page 64648]]

             Table VIII-3--Estimated Impact on Steam Electric Facilities as a Group at the Year 2030
----------------------------------------------------------------------------------------------------------------
                                                      Change attributable to regulatory option as compared to
                                                                             baseline
                                                 ---------------------------------------------------------------
             Metric               Baseline value             Option 2                        Option 4
                                                 ---------------------------------------------------------------
                                                       Value          Percent          Value          Percent
----------------------------------------------------------------------------------------------------------------
Total capacity (MW).............         336,872           2,880             0.9           3,194             0.9
Early retirements or closures             58,192          -2,880            -4.9          -3,194            -5.5
 \a\ (MW).......................
Early retirements or closures                 79               0             0.0              -1            -1.3
 \a\ (number of plants).........
Total generation (GWh)..........       1,570,513           4,676             0.3           1,235             0.1
Variable production cost (2018$/          $26.00           $0.02             0.1           $0.05             0.2
 MWh)...........................
Annual costs (million 2018$)....         $60,298             $98             0.2            $103             0.1
----------------------------------------------------------------------------------------------------------------
\a\ Values for incremental early retirements or closures represent change relative to the baseline. IPM may show
  partial (unit) or full facility early retirements (closures). It may also show avoided closures (negative
  closure values) in which a boiler or facility that is projected to close in the baseline is estimated to
  continue operating in the policy case.

    Under proposed Option 2, generation at steam electric facilities is 
projected to increase by 4,676 GWh (0.3 percent) nationally, when 
compared to the baseline. IPM V6 projects a net increase in total steam 
electric capacity by 2,880 MW or approximately 0.9 percent of total 
baseline capacity, but no net change in the number of full facility 
retirements and the net avoidance of three partial retirements (unit 
closures) nationwide indicating a higher capacity utilization by these 
facilities. See Section 5.2.2.2 in the RIA for details.
    IPM V6 projects generation at steam electric facilities increases 
under Option 4 by 1,235 GWh (0.1 percent) nationally, which is smaller 
in magnitude than the increase under Option 2. National level results 
for steam electric facilities under Option 4 show an increase in total 
steam electric capacity of 3,194 MW (0.9 percent of the baseline). At 
the national level, IPM projects one net avoided full facility closure 
and the same three avoided partial retirements as for Option 2. See 
Section 5.2.2.2 in the RIA for details.
    These findings suggest that all of the regulatory options in this 
proposal can be expected to have small economic consequences for the 
steam electric facilities as a group. Options 2 and 4 also affect the 
operating status of very few steam electric facilities, with no net 
change in facility closures under Option 2, and one net avoided closure 
under Option 4.\87\ For further discussion of closures and related 
distributional impacts, see Chapter 5 of the RIA.
---------------------------------------------------------------------------

    \87\ The additional closure under Option 2 is not a result of 
the facility incurring costs under this proposed rule. The IPM model 
predicts this facility becomes uneconomical due to the increased 
generation from other coal facilities in the same NERC region.
---------------------------------------------------------------------------

    Because the analysis of the proposed options discussed in the RIA 
was completed before the EPA finalized the ACE rule, this analysis does 
not include the projected effects of the ACE rule. Thus, the EPA 
conducted a supplemental IPM run with the costs of Option 2 on a 
baseline that includes the ACE illustrative case presented in the ACE 
final rule (see Appendix C in RIA). A summary of these results is 
presented in Table VIII-4.

 Table VIII-4--Estimated Impact of ELG Option 2 on Steam Electric Power Plants as a Group at the Year 2030, for
                                  Sensitivity Analysis Including ACE Final Rule
----------------------------------------------------------------------------------------------------------------
                                                                              Option 2 with ACE rule
                     Metric                        Baseline with -----------------------------------------------
                                                     ACE rule          Value        Difference    Percent change
----------------------------------------------------------------------------------------------------------------
Early retirements or closures \a\ (MW)..........         336,547         339,654          -3,107            -0.9
Early retirements or closures \a\ (number of                  78              79               1             1.3
 plants)........................................
Total generation (GWh)..........................       1,569,109       1,576,455           7,345             0.5
Variable production cost (2018$/MWh)............          $25.85          $25.87           $0.02             0.1
Annual costs (million 2018$)....................         $60,387         $60,578            $191             0.3
----------------------------------------------------------------------------------------------------------------
\a\ Values for incremental early retirements or closures represent change relative to the baseline. IPM may show
  partial (unit) or full facility early retirements (closures). It may also show avoided closures (negative
  closure values) in which a boiler or facility that is projected to close in the baseline is estimated to
  continue operating in the policy case.

    Examining the incremental impacts of Option 2 on a baseline 
including ACE, generation at steam electric facilities is projected to 
increase by 3,107 GWh (0.9 percent) nationally. IPM V6 projects a net 
increase in total steam electric capacity by 7,345 MW or approximately 
0.5 percent of total baseline capacity. There is one incremental full 
facility retirement as well as the net avoidance of four partial 
retirements (unit closures) nationwide indicating a higher capacity 
utilization by these facilities. See Appendix C of the RIA for further 
details.
b. Impacts on Individual Facilities Incurring Costs
    To assess potential facility-level effects, the EPA also analyzed 
facility-specific changes attributable to the regulatory options in 
Table VII-1 for the following metrics: (1) Capacity utilization 
(defined as annual generation (in MWh) divided by [capacity (MW) times 
8,760 hours]) (2) electricity generation, and (3) variable production 
costs per MWh, defined as variable O&M cost plus fuel cost divided by 
net generation. The analysis of changes in individual facilities is 
detailed in Chapter 5 of the RIA.
    The results for both Option 2 and Option 4 show no change, or less 
than a one percent reduction or one percent increase for steam electric 
facilities projected to incur ELG compliance costs. For Option 2, a 
greater number of facilities see improving operating

[[Page 64649]]

conditions (i.e., higher capacity utilization or generation, lower 
variable production costs) than deteriorating conditions. Effects under 
Option 4 are similar, although approximately the same number of 
facilities see positive changes in operating conditions as negative 
changes. Thus, the results for the subset of facilities incurring costs 
further support the conclusion that the effects of any of the 
regulatory options in this proposed rule on the steam electric power 
generating industry will be less than that of the 2015 rule. This 
conclusion holds when including the effects of the ACE final rule, as 
detailed in Appendix C of the RIA for proposed Option 2.

IX. Changes to 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 industry as a whole. In 
estimating pollutant reductions associated with this proposal, the EPA 
took the same approach as described above for facility-specific costs. 
That is, the EPA compared the values to a baseline that reflects 
implementation of existing environmental regulations, including the 
2015 rule. In the 2015 rule, the baseline did not reflect pollutant 
loading reductions for achieving the 2015 rule requirements as that 
impact is what EPA analyzed. Here, the baseline appropriately includes 
pollutant loading reductions for achieving the 2015 rule requirements 
as the EPA is analyzing the impact resulting from any changes to those 
requirements. More specifically, the EPA considered the change in the 
pollutant loading reductions associated with the regulatory options in 
this proposal to those projected under the baseline.
    The general methodology that the EPA used to calculate pollutant 
loadings is the same as that described in the 2015 rule. The EPA used 
data collected for the 2015 rule, as well as the data described in 
Section VI, to characterize pollutant concentrations for FGD wastewater 
and bottom ash transport water. The EPA evaluated these data sources to 
identify analytical data that meet EPA's acceptance criteria for 
inclusion in analyses for characterizing discharges of FGD wastewater 
and bottom ash transport water. For each plant discharging FGD 
wastewater or bottom ash transport water, the EPA used data from the 
2009 survey and/or industry-submitted data to determine the discharge 
flow rates for FGD wastewater and bottom ash transport water. The EPA 
adjusted the discharge flow rates used in the pollutant loadings 
estimates to account for retirements, fuel conversions, and other 
changes in operations scheduled to occur by December 31, 2028, 
described in Section 6 of the Supplemental TDD, that will eliminate or 
alter the discharge of an applicable wastestream. Finally, the Agency 
adjusted the discharge flow rates to account for changes in plant 
operations to optimize FGD wastewater flows and to comply with the CCR 
rule. For further discussion of these adjustments see Section 6.2.2 and 
6.3.2 of the Supplemental TDD, respectively.
    The EPA first estimated--on an annual, per facility basis--the 
pollutant discharge load for FGD wastewater and BA transport water 
associated with the technology basis evaluated for facilities to comply 
with the 2015 rule requirements for FGD wastewater and BA transport 
water relative to the conditions currently present or planned at each 
facility. The EPA similarly estimated facility-specific post-compliance 
pollutant loadings associated with the technology bases for facilities 
to comply with effluent limitations based on each of the regulatory 
options in this proposal. For each regulatory option, the EPA then 
calculated the changes in pollutant loadings at a particular facility 
as the sum of the differences between the estimated baseline and post-
compliance discharge loadings for each applicable wastestream.
    For those facilities that discharge indirectly to POTWs, the EPA 
adjusted the baseline and option loadings to account for pollutant 
removals expected from POTWs. These adjusted pollutant loadings for 
indirect dischargers therefore approximate the resulting discharges to 
receiving waters. For additional details on the methodology the EPA 
used to calculate pollutant loading reductions, see Section 6 of the 
Supplemental TDD.

A. FGD Wastewater

    For FGD wastewater, the EPA continued to use the average pollutant 
effluent concentration with facility-specific discharge flow rates to 
estimate the mass pollutant discharge per facility for baseline and 
each regulatory option in Table VII-1. The EPA used data compiled for 
the 2015 rule as the initial basis for estimating discharge flow rates 
and updated the data to reflect retirements or other relevant changes 
in operation. For example, the EPA reviewed state and EIA data to 
identify flow rates for new scrubbers that have come online since the 
2015 rule. The EPA also accounted for increased rates of recycle 
through the scrubber that would affect the discharge flow.
    The EPA assigned pollutant concentrations for each analyte based on 
the operation of a treatment system designed to comply with the 
baseline or the regulatory options considered. The EPA used data 
compiled for the 2015 rule to characterize untreated FGD purge, 
chemical precipitation effluent, and chemical precipitation plus high 
hydraulic residence time biological reduction effluent. The EPA used 
data provided by industry to characterize effluent quality for chemical 
precipitation plus LRTR and membrane filtration effluent. In addition, 
the EPA used data provided by industry and other stakeholders as 
described in Section VI of this preamble to quantify bromide in FGD 
wastewater under baseline conditions and for the regulatory options.

B. BA Transport Water

    The EPA estimated baseline and post-compliance loadings for each 
regulatory option in Table VII-1 using pollutant concentrations for BA 
transport water and facility-specific flow rates. The EPA used data 
compiled for the 2015 rule as the basis for estimating BA transport 
water discharge flows and updated the data set to reflect retirements 
and other relevant changes in operation (e.g., ash handling 
conversions, fuel conversions) that occurred after the 2015 rule data 
were collected. For the high recycle rate technology option, the EPA 
also estimated discharge flows associated with the purge from remote 
MDS operation, based on the boiler capacity and the volume of the 
remote MDS. Under the baseline, which reflects the 2015 rule limitation 
of zero discharge, the EPA estimated a flow rate of zero.
    For this proposed rule, in response to the administrative petitions 
discussed in Section IV of this preamble, the EPA was able to use a 
revised set of the 2015 rule analytical data to characterize BA 
transport water effluent from steam electric facilities. As an example, 
the EPA re-evaluated and revised, as appropriate, its data sets in 
light of questions petitioners raised about the inclusion and validity 
of certain data due, in part, to what the petitioners assert are flaws 
in data acceptance criteria, obsolete analytical methods, and the 
treatment of non-detect analytical results, which petitioners believed 
resulted in an overestimation of pollutant loadings resulting from 
current practices for BA transport water, in turn resulting in an 
overestimation of pollutant removals under the 2015 rule. The EPA also 
updated the data set and incorporated BA transport water

[[Page 64650]]

sampling data submitted by industry during the final months of the 2015 
rule and as part of a voluntary sampling program described in Section 
VI of this preamble. For a detailed discussion, see Section 6 of the 
Supplemental TDD.

C. Summary of Incremental Changes of Pollutant Loadings From Proposed 
Regulatory Options

    Table IX-1 summarizes the net change to annual pollutant loadings, 
compared to baseline, associated with each regulatory option in Table 
VII-1.

  Table IX-1--Estimated Incremental Changes to Annual Pollutant Loading
for Proposed Regulatory Options 1, 2, 3, and 4 [in pounds/year] Compared
                               to Baseline
------------------------------------------------------------------------
                                                Changes in pollutant
           Regulatory option \a\                      loadings
------------------------------------------------------------------------
1.........................................                    13,400,000
2.........................................                  -104,000,000
3.........................................                  -276,000,000
4.........................................                -1,320,000,000
------------------------------------------------------------------------
Note: Changes in pollutant loadings are rounded to three significant
  figures.
\a\ Negative values represent an estimated decrease in loadings to
  surface waters compared to baseline. Positive values represent an
  estimated increase in loadings to surface waters compared to baseline.

    Compared to the 2015 rule, Options 2, 3 and 4 result in decreased 
pollutant loadings to surface waters. Reductions under Options 2 and 3 
would be realized to the extent that operators chose to meet the 
limitations based on membrane filtration under the proposed revisions 
of VIP for FGD wastewater. Under Option 2, the EPA estimated that 18 
plants (27 percent of plants estimated to incur FGD compliance costs) 
would opt into the VIP program and under Option 3 the number rises to 
23 plants (34 percent of plants estimated to incur FGD compliance 
costs).

X. 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 Act require the EPA to consider non-water quality 
environmental impacts (including energy impacts) associated with ELGs. 
Accordingly, the EPA has considered the potential impact of the 
regulatory options in today's proposal on air emissions, solid waste 
generation, and energy consumption. For the reasons described in 
Section IX of this preamble, the baseline for these analyses 
appropriately includes non-water quality environmental impacts 
associated with achieving the 2015 rule requirements, and the EPA is 
analyzing the incremental impacts resulting from the regulatory options 
presented in Table VII-1 compared to those projected under the 
baseline. In general, the EPA used the same methodology to conduct the 
current analysis (with updated data as applicable) as it did for the 
analysis supporting the 2015 rule. The following summarizes the 
methodology and results. See Section 7 of the Supplemental TDD for 
additional details.

A. Energy Requirements

    Steam electric facilities use energy when transporting ash and 
other solids on or off site, operating wastewater treatment systems 
(e.g., chemical precipitation, biological treatment), or operating ash 
handling systems. For today's proposal, the EPA considered whether 
there would be an associated change in the incremental energy 
requirements compared to baseline. Energy requirements vary depending 
on the regulatory option evaluated and the current operations of the 
facility. Therefore, as applicable, the EPA estimated the increase in 
energy usage in megawatt hours (MWh) for equipment added to the 
facility systems or in consumed fuel (gallons) for transportation/
operating equipment for baseline and all regulatory options. The EPA 
summed the facility-specific estimates to calculate the net change in 
energy requirements from baseline for the regulatory options.
    The EPA estimated the amount of energy needed to operate wastewater 
treatment systems and ash handling systems based on the horsepower 
rating of the pumps and other equipment. The EPA also estimated the 
fuel consumption associated with the changes in transportation needed 
to landfill solid waste and combustion residuals (e.g., ash) at steam 
electric facilities (on-site or off-site). The frequency and distance 
of transport depends on a facility's operation and configuration; 
specifically, the volume of waste generated and the availability of 
either an on-site or off-site non-hazardous landfill and its distance 
from the facility. Table X-1 shows the net change in annual electrical 
energy usage associated with the regulatory options compared to 
baseline, as well as the net change in annual fuel consumption 
requirements associated with the regulatory options compared to 
baseline.

  Table X-1--Estimated Incremental Change in Energy Requirements Associated With Regulatory Options Compared to
                                                    Baseline
----------------------------------------------------------------------------------------------------------------
                                                         Energy use associated with regulatory options \a\
            Non-water quality impact             ---------------------------------------------------------------
                                                     Option 1        Option 2        Option 3        Option 4
----------------------------------------------------------------------------------------------------------------
Electrical Energy Used (MWh)....................         -82,300         -54,570         -27,000          94,000
Fuel Used (Thousand Gallons)....................               0         -48,000          40,000         243,000
----------------------------------------------------------------------------------------------------------------
\a\ Negative values represent a decrease in energy use compared to baseline. Positive values represent an
  increase in energy use compared to baseline.

[[Page 64651]]

B. Air Pollution

    The regulatory options are expected to affect air pollution through 
three main mechanisms: (1) Changes in auxiliary electricity use by 
steam electric facilities to operate wastewater treatment, ash 
handling, and other systems needed to meet regulatory standards; (2) 
changes to transportation-related emissions due to the trucking of CCR 
waste to landfills; and (3) the change in the profile of electricity 
generation due to any regulatory requirements. This section discusses 
air emission changes associated with the first two mechanisms and 
presents the corresponding estimated net change in air emissions. See 
Section XII of this preamble for additional discussion of the third 
mechanism.
    Steam electric facilities generate air emissions from operating 
transport vehicles, such as dump trucks, which release criteria air 
pollutants and greenhouse gases when operated. Similarly, a decrease in 
energy use or vehicle operation would result in decreased air 
pollution.
    To estimate the net air emissions associated with changes in 
electrical energy use projected as a result of the regulatory options 
in today's 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 used emission factors projected by IPM V6 
(ton/MWh) for nitrogen oxides, sulfur dioxide, and carbon dioxide to 
generate estimates of the changes in air emissions associated with 
changes in energy production for Options 2 and 4 compared to 
baseline.\88\
---------------------------------------------------------------------------

    \88\ Only Options 2 and 4 were run through IPM; however, 
extrapolated net benefits from air impacts for Options 1 and 3 are 
available in Chapter 8 of the Benefit Cost Analysis report.
---------------------------------------------------------------------------

    To estimate net air emissions associated with the change in 
operation of transport vehicles, the EPA used the MOVES2014b model to 
identify air emission factors (grams per mile) for the air pollutants 
of interest. The EPA estimated the annual number of miles that dump 
trucks moving ash or 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 Options 
2 and 4 compared to baseline. Table X-2 presents EPA's estimated net 
change in air emissions associated with auxiliary electricity and 
transportation.

    Table X-2--Estimated Net Change in Industry-Level Air Emissions Associated With Auxiliary Electricity and
                               Transportation for Options Compared to Baseline a b
----------------------------------------------------------------------------------------------------------------
                                                                 Change in emissions--    Change in emissions--
                   Non-water quality impact                      Option 2  (tons/year)     Option 4 (tons/year)
                                                                          \b\                      \c\
----------------------------------------------------------------------------------------------------------------
NOX...........................................................                    -32.7                     32.7
SOX...........................................................                    -54.3                     20.4
CO2...........................................................                  -44,600                   60,600
----------------------------------------------------------------------------------------------------------------
\a\ Negative values represent a decrease in energy use compared to baseline. Positive values represent an
  increase in energy use compared to baseline.
\b\ Option 2 estimates are based on the IPM sensitivity analysis scenario that includes the ACE rule in the
  baseline (IPM-ACE).
\c\ Option 4 estimates are based on IPM analysis scenario that does not include the ACE rule in the baseline.

    The modeled output from IPM V6 predicts changes in electricity 
generation due to compliance costs attributable to Options 2 and 4 
compared to baseline. These changes in electricity generation are, in 
turn, predicted to affect the amount of NOX, SO2, 
and CO2 emissions from steam electric facilities. A summary 
of the net change in annual air emissions under Options 2 and 4 for all 
three mechanisms is shown in Table X-3. Similar to costs, the IPM V6 
results from these options reflect the range of NWQEI associated with 
all four regulatory options. To provide some perspective on the 
estimated changes in annual air emissions, EPA compared the estimated 
change in air emissions to the net amount of air emissions generated in 
a year by all electric power facilities throughout the United States. 
For a more details on the sources of air emission changes, see Section 
7 of the Supplemental TDD.

     Table X-3--Estimated Net Change in Industry-Level Air Emissions Associated With Changes in Electricity
                                   Generation for Options Compared to Baseline
----------------------------------------------------------------------------------------------------------------
                                                                                            2016 Emissions by
                                        Change in emissions--    Change in emissions--        electric power
       Non-water quality impact        Option 2 (million tons)  Option 4 (million tons)    generating industry
                                                 \a\                      \b\                 (million tons)
----------------------------------------------------------------------------------------------------------------
NOX..................................                    0.005                    0.001                     1.47
SOX..................................                    0.005                    0.002                     1.63
CO2..................................                     5.66                     1.24                    2,030
----------------------------------------------------------------------------------------------------------------
\a\ Option 2 emissions are based on the IPM sensitivity analysis scenario that includes the ACE rule in the
  baseline.
\b\ Option 4 emissions are based on the IPM sensitivity analysis scenario that does not include the ACE rule in
  the baseline.

C. Solid Waste Generation and Beneficial Use

    Steam electric facilities generate solid waste associated with 
sludge from wastewater treatment systems (e.g., chemical precipitation, 
biological treatment). The EPA estimated the change in the amount of 
solids generated under each regulatory option for each facility in 
comparison to the baseline. For FGD wastewater treatment, Regulatory 
Options 2, 3, and 4 result in an increase in the amount of solid waste 
generated compared to baseline. The

[[Page 64652]]

solid waste generation associated with Option 1 is comparable to 
baseline. While BA solids are also generated at steam electric 
facilities, all of the BA solids accounted for in the waste volumes 
disposed in the 2015 rule analysis were suspended solids from 
combustion, and therefore the regulatory options in today's proposal do 
not alter the amount of BA or other combustion residuals generated. 
Table X-4 shows the net change in annual solid waste generation, 
compared to baseline, associated with the proposed regulatory options.

 Table X-4--Estimated Incremental Changes to Solid Waste Generation Associated With Regulatory Options Compared
                                                   to Baseline
----------------------------------------------------------------------------------------------------------------
                                                   Solid waste generation associated with regulatory options
          Non-water quality impact           -------------------------------------------------------------------
                                                  Option 1         Option 2         Option 3         Option 4
----------------------------------------------------------------------------------------------------------------
Solids Generated (tons/year)................               0          328,000          487,000        2,326,000
----------------------------------------------------------------------------------------------------------------

    The EPA also evaluated the potential impacts of diverting FA from 
current beneficial uses toward encapsulation of brine (from membrane 
filtration) for disposal in landfills. According to the latest ACAA 
survey,\89\ over half of the FA generated by coal-fired facilities is 
being sold for beneficial uses rather than disposed of, and the 
majority of this beneficially used FA is replacing Portland cement in 
concrete. This also holds true for the specific facilities currently 
discharging FGD wastewater, as seen by sales of FA in the 2016 EIA-923 
Schedule 8A.\90\ Summary statistics of the FA beneficial use percentage 
for these facilities are displayed in Table X-5 below.
---------------------------------------------------------------------------

    \89\ Available online at: https://www.acaa-usa.org/Portals/9/Files/PDFs/2016-Survey-Results.pdf.
    \90\ Available online at: https://www.eia.gov/electricity/data/eia923/.

     Table X-5--Percent of FA Sold for Beneficial Use by Facilities
                       Discharging FGD Wastewater
------------------------------------------------------------------------
                                                           Percent of FA
                        Statistic                            sold for
                                                          beneficial use
------------------------------------------------------------------------
Min.....................................................               0
10th percentile.........................................               0
25th percentile.........................................               3
Mean....................................................              48
Median..................................................              50
75th percentile.........................................              88
90th percentile.........................................              98
Max.....................................................             100
------------------------------------------------------------------------

    In the EPA's coal combustion residuals disposal rule,\91\ the EPA 
noted that FA replacing Portland cement in concrete would result in 
significant avoided environmental impacts to energy use, water use, 
greenhouse gas emissions, air emissions, and waterborne wastes. 
Although the EPA cannot tie specific facilities selling their FA to 
this specific beneficial use, over half of the FA beneficially used 
currently replaces Portland cement in concrete. Therefore, where sale 
for this particular beneficial use occurs by facilities that may 
otherwise use their fly ash to encapsulate membrane filtration brine 
under Option 4, the EPA proposes to find that unacceptable air and 
other non-water quality environmental impacts will result.
---------------------------------------------------------------------------

    \91\ Available online at: http://www.regulations.gov Docket ID: 
EPA-HQ-RCRA-2009-0640.
---------------------------------------------------------------------------

D. Changes in Water Use

    Steam electric facilities generally use water for handling solid 
waste, including ash, and for operating wet FGD scrubbers. The BA 
handling technologies associated with baseline and the regulatory 
options in today's proposal for BA transport water eliminate or reduce 
water use associated with wet sluicing BA operating systems. The 2015 
rule baseline requires zero discharge of pollutants in BA transport 
water, and because the use of other wastewater could significantly 
increase the necessary purge flow to maintain water chemistry, the EPA 
estimated the increase in water use for BA handling associated with 
Options 1, 2, 3, and 4 compared to baseline as equal to the BA purge 
flow.
    Two of the three technology bases for FGD wastewater included in 
the regulatory options in today's proposal, chemical precipitation and 
chemical precipitation plus LRTR, are not expected to reduce or 
increase the amount of water use. Facilities that install a membrane 
filtration system for FGD wastewater treatment under Option 2 or 3 as 
part of the VIP option, or under Option 4, are assumed to decrease 
water use compared to baseline by recycling all permeate back into the 
FGD system, which would avoid costs of pumping or treating new makeup 
water. Therefore, the EPA estimated this reduction in water use 
resulting from membrane filtration treatment based on the estimated 
volume of the permeate stream from the membrane filtration system. 
Table X-6 sums the changes for FGD wastewater and BA transport water 
and shows the net change in water use, compared to baseline, for the 
proposed regulatory options.

[[Page 64653]]

  Table X-6--Estimated Incremental Changes to Water Use Associated With Regulatory Options Compared to Baseline
----------------------------------------------------------------------------------------------------------------
                                                    Changes to water use associated with regulatory options
          Non-water quality impact           -------------------------------------------------------------------
                                                  Option 1         Option 2         Option 3         Option 4
----------------------------------------------------------------------------------------------------------------
Changes in Water Use (gallons/year).........       3,370,000       21,100,000          613,000       -9,380,000
----------------------------------------------------------------------------------------------------------------

XI. Environmental Assessment

A. Introduction

    The EPA conducted an environmental assessment for this proposed 
rule. The environmental assessment reviewed currently available 
literature on the documented environmental and human health impacts of 
steam electric power facility FGD wastewater and BA transport water 
discharges and conducted modeling to determine the impacts of pollution 
from the universe of steam electric facilities to which the steam 
electric ELGs apply. For the reasons described in Section VIII of this 
preamble, in conducting these analyses, the baseline appropriately 
evaluates environmental and human health impacts of achieving the 2015 
rule requirements as the EPA is analyzing the impact resulting from any 
changes to those requirements compared to the 2015 rule (the same 
baseline used to evaluate costs). More specifically, the EPA considered 
the change in impacts associated with the regulatory options presented 
in Table VII-1 in relation to those projected under the baseline.
    Information from the EPA's review of the scientific literature and 
documented cases of impacts of steam electric power facility FGD 
wastewater and BA transport water discharges on human health and the 
environment, as well as a description of the EPA's modeling methodology 
and results, are provided in the Supplemental Environmental Assessment 
(Supplemental EA). The Supplemental EA contains information on 
literature that the EPA has reviewed since the 2015 rule, updates to 
the modeling methodology and modeling results for each of the 
regulatory options in today's proposal. The 2015 EA provides 
information from the EPA's earlier review of the scientific literature 
and documented cases of the full spectrum of impacts associated with 
the wider range of steam electric power facility wastewater discharges 
addressed in the 2015 rule on human health and the environment, as well 
as a full description of the EPA's modeling methodology.
    Current scientific literature indicates that untreated steam 
electric power facility wastewaters, such as FGD wastewater and BA 
transport water, contain large amounts of a wide range of pollutants, 
some of which are toxic and bioaccumulative, and which cause 
detrimental environmental and human health impacts. For additional 
information, see Section 2 of the Supplemental EA. The EPA also 
considered environmental and human health effects associated with 
changes in air emissions, solid waste generation, and water 
withdrawals. Sections X and XII discuss these effects.

B. Updates to the Environmental Assessment Methodology

    The environmental assessment modeling for today's proposed rule 
consisted of the steady-state, national-scale immediate receiving water 
(IRW) model that was used to evaluate the direct and indirect 
discharges from steam electric facilities in the 2015 final ELG rule 
and 2015 final CCR rule.\92\ The model focused on impacts within the 
immediate surface waters where the discharges occur (approximately 0.5 
to 6 miles from the outfall). The EPA also modeled receiving water 
concentrations downstream from steam electric power facility discharges 
using a downstream fate and transport model (see Section XII of this 
preamble).
---------------------------------------------------------------------------

    \92\ These rules modeled the same waterbodies for which the 
model was peer reviewed in 2008.
---------------------------------------------------------------------------

    The environmental assessment also incorporates changes to the 
industry profile outlined in Section V of this preamble. Additionally, 
the EPA updated and improved several input parameters for the IRW 
model, including receiving water boundaries and volumetric flow data 
from National Hydrography Dataset Plus (NHDPlus) Version 2, updated 
national recommended water quality criteria (WQC) for cadmium and 
selenium, updated benchmarks for ecological impacts in benthic 
sediment, and an updated bioconcentration factor for cadmium.

C. Outputs From the Environmental Assessment

    The EPA estimates small environmental and ecological changes 
associated with changes in pollutant loadings for the regulatory 
options presented in Table VII-1 as compared to the baseline, including 
small changes in impacts to wildlife and humans. More specifically, in 
addition to other unquantified environmental changes, the environmental 
assessment evaluated changes in (1) surface water quality, (2) impacts 
to wildlife, (3) number of receiving waters with potential human health 
cancer risks, (4) number of receiving waters with potential to cause 
non-cancer human health effects, and (5) nutrient impacts.
    The EPA focused its quantitative analyses on the changes in 
environmental and human health impacts associated with exposure to 
toxic bioaccumulative pollutants via the surface water pathway. The EPA 
modeled changes in discharges of toxic, bioaccumulative pollutants from 
both FGD wastewater and BA transport water into rivers and streams and 
lakes and ponds, including reservoirs. The EPA addressed environmental 
impacts from nutrients in a separate analysis discussed in Section XII 
of this preamble.
    The environmental assessment concentrates on impacts to aquatic 
life based on changes in surface water quality; impacts to aquatic life 
based on changes in sediment quality within surface waters; impacts to 
wildlife from consumption of contaminated aquatic organisms; and 
impacts to human health from consumption of contaminated fish and 
water. The Supplemental EA discusses, with quantified results, the 
estimated environmental changes projected within the immediate 
receiving waters due to the estimated pollutant loading changes 
associated with the regulatory options in today's proposal compared to 
the 2015 rule. All of the modeled changes are small in magnitude.

XII. Benefits Analysis

    This section summarizes the EPA's estimates of the changes in 
national environmental benefits expected to result from potential 
changes in steam electric facility wastewater discharges described in 
Section IX of this preamble, and the resultant environmental effects, 
summarized in Section XI. The Benefit Cost Analysis

[[Page 64654]]

(BCA) report provides additional details on the benefits methodologies 
and analyses, including uncertainties and limitations. The analysis 
methodology for quantified benefits is generally the same as that used 
by the EPA for the 2015 rule, but with revised inputs and assumptions 
that reflect updated data. The EPA has updated the methodology from the 
Stage 2 Disinfection Byproduct Rule for estimating benefits of reducing 
bladder cancer incidence related to bromide discharges from steam 
electric facilities and associated brominated disinfection by-product 
formation at drinking water treatment facilities.

A. Categories of Benefits Analyzed

    Table XII-1 summarizes benefit categories associated with the 
proposed regulatory options and notes which categories the EPA was able 
to quantify and monetize. Analyzed benefits fall into six broad 
categories: Human health benefits from surface water quality 
improvements, ecological conditions and effects on recreational use 
from surface water quality changes, market and productivity benefits, 
air-related effects, and changes in water withdrawal. Within these 
broad categories, the EPA was able to assess changes in the benefits 
projected for the regulatory options in today's proposal with varying 
degrees of completeness and rigor. Where possible, the EPA quantified 
the expected changes in effects and estimated monetary values. However, 
data limitations, modeling limitations, and gaps in the understanding 
of how society values certain environmental changes prevent the EPA 
from quantifying and/or monetizing some benefit categories. In the 
following discussion, positive benefit values represent improvements in 
environmental conditions and negative values represent forgone benefits 
of the proposed options compared to the baseline.

 Table XII-1--Summary of Benefits Categories Associated With Changes in Pollutant Discharges From Steam Electric
                                                   Facilities
----------------------------------------------------------------------------------------------------------------
                                                                 Quantified but not      Neither quantified nor
         Benefit category           Quantified and monetized          monetized                 monetized
----------------------------------------------------------------------------------------------------------------
                            Human Health Benefits from Surface Water Quality Changes
----------------------------------------------------------------------------------------------------------------
Changes in incidence of bladder     [check].................  ........................  ........................
 cancer from exposure to total
 trihalomethanes (TTHM) in
 drinking water.
Changes in incidence of cancer      [check].................  ........................  ........................
 from arsenic exposure via fish
 consumption.
Changes in incidence of             ........................  ........................  [check]
 cardiovascular disease from lead
 exposure via fish consumption.
Changes in incidence of other       ........................  [check].................  [check]
 cancer and non-cancer adverse
 health effects (e.g.,
 reproductive, immunological,
 neurological, circulatory, or
 respiratory toxicity) due to
 exposure to arsenic, lead,
 cadmium, and other toxics from
 fish consumption or drinking
 water.
Changes in IQ loss in children      [check].................  ........................  ........................
 from lead exposure via fish
 consumption.
Changes in need for specialized     [check].................  ........................  ........................
 education for children from lead
 exposure via fish consumption.
Changes in in utero mercury         [check].................  ........................  ........................
 exposure via maternal fish
 consumption.
Changes in health hazards from      ........................  ........................  [check]
 exposure to pollutants in waters
 used recreationally (e.g.,
 swimming).
----------------------------------------------------------------------------------------------------------------
            Ecological Conditions and Effects on Recreational Use from Surface Water Quality Changes
----------------------------------------------------------------------------------------------------------------
Benefits from changes in surface    [check].................  ........................  ........................
 water quality, including: Aquatic
 and wildlife habitat; water-based
 recreation, including fishing,
 swimming, boating, and nearwater
 activities; aesthetic benefits,
 such as enhancement of adjoining
 site amenities (e.g., residing,
 working, traveling, and owning
 property near the water; \a\ and
 non-use value (existence, option,
 and bequest value from improved
 ecosystem health) \a\.
Benefits from protection of         ........................  [check].................  ........................
 threatened and endangered
 species.
Changes in sediment contamination.  ........................  ........................  [check]
----------------------------------------------------------------------------------------------------------------
                                        Market and Productivity Benefits
----------------------------------------------------------------------------------------------------------------
Changes in impoundment failures.    ........................  ........................  [check]
Changes in water treatment costs    ........................  ........................  [check]
 for municipal drinking water,
 irrigation water, and industrial
 process.
Changes in commercial fisheries     ........................  ........................  [check]
 yields.
Changes in tourism and              ........................  ........................  [check]
 participation in water-based
 recreation.
Changes in property values from     ........................  ........................  [check]
 water quality changes.
Changes in ability to market coal   ........................  ........................  [check]
 combustion byproducts.
Changes in maintenance dredging of  [check].................  ........................  ........................
 navigational waterways and
 reservoirs due to changes in
 sediment discharges.
----------------------------------------------------------------------------------------------------------------
                                               Air-Related Effects
----------------------------------------------------------------------------------------------------------------
Human health benefits from changes  ........................  [check].................  ........................
 in morbidity and mortality from
 exposure to NOX, SO2 and
 particulate matter (PM2.5).
Avoided climate change impacts      [check].................  ........................  ........................
 from CO2 emissions.
----------------------------------------------------------------------------------------------------------------
                                           Changes in Water Withdrawal
----------------------------------------------------------------------------------------------------------------
Changes in the availability of      [check].................  ........................  ........................
 groundwater resources.
Changes in impingement and          ........................  ........................  [check]
 entrainment of aquatic organisms.

[[Page 64655]]

 
Changes in susceptibility to        ........................  ........................  [check]
 drought.
----------------------------------------------------------------------------------------------------------------
\a\ These values are implicit in the total willingness-to-pay (WTP) for water quality improvements.

    The following section summarizes the EPA's analysis of the benefit 
categories that the Agency was able to quantify and/or monetize 
(identified in the second and third columns of Table XII-1, 
respectively). Benefits are a function of not only the changes in 
pollutant loadings under the various options, but also the timing of 
those options. For example, although loadings increase more under 
Option 1, treatment technologies are in place sooner, resulting in 
fewer forgone lead, mercury, and arsenic-related human health benefits 
under Option 1 than under more stringent options that may be installed 
in the future. The regulatory options would also affect additional 
benefit categories that the Agency was not able to monetize. The BCA 
Report further describes some of these additional nonmonetized 
benefits.

B. Quantification and Monetization of Benefits

1. Changes in Human Health Benefits From Changes in Surface Water 
Quality
    Changes in pollutant discharges from steam electric facilities 
affect human health benefits in multiple ways. Exposure to pollutants 
in steam electric power facility discharges via consumption of fish 
from affected waters can cause a wide variety of adverse health 
effects, including cancer, kidney damage, nervous system damage, 
fatigue, irritability, liver damage, circulatory damage, vomiting, 
diarrhea, brain damage, IQ loss, and many others. Exposure to drinking 
water containing brominated disinfection by-products could cause 
adverse health effects such as cancer and reproductive and fetal 
development issues. Because the regulatory options in this proposal 
would change discharges of steam electric pollutants into waterbodies 
that receive or are downstream from these discharges, they may alter 
incidence of associated illnesses, even if by small amounts. These 
analyses, which are detailed in Chapters 4 and 5 of the BCA, find that 
the incremental changes in exposure between the baseline and regulatory 
options are minimal compared to the absolute changes for those same 
pollutants evaluated in the 2015 rule.
    Due to data limitations and uncertainties, the EPA is able to 
monetize only a subset of the changes in health benefits associated 
with changes in pollutant discharges from steam electric facilities 
resulting from the regulatory options in this proposal as compared to 
the baseline. The EPA monetized these changes in human health effects 
by estimating the change in the expected number of individuals 
experiencing adverse human health effects in the populations exposed to 
steam electric discharges and/or altered exposure levels for the 
regulatory options relative to the baseline, and valuing these changes 
using different monetization methods for different benefit endpoints.
    The EPA estimated changes in health risks from the consumption of 
contaminated fish from waterbodies within 50 miles of households. The 
EPA used Census Block population data and state-specific average 
fishing rates to estimate the exposed population. The EPA used cohort-
specific fish consumption rates and waterbody-specific fish tissue 
concentration estimates to calculate potential exposure to steam 
electric pollutants. Cohorts were defined by age, sex, race/ethnicity, 
and fishing mode (recreational or subsistence). The EPA used these data 
to quantify and monetize changes in the following five categories of 
human health effects, which are further detailed in the BCA Report:
     Changes in IQ Loss in Children Aged Zero to Seven from 
Lead Exposure via Fish Consumption.
     Changes in Need for Specialized Education for Children 
from Lead Exposure via Fish Consumption.
     Changes in In Utero Mercury Exposure via Maternal Fish 
Consumption and Associated IQ Loss.
     Changes in Incidence of Cancer from Arsenic Exposure via 
Fish Consumption.
    Table XII-2 summarizes the monetary value of changes in all 
estimated health outcomes associated with consumption of contaminated 
fish tissue for the ELG options compared to the baseline. Chapter 5 of 
the BCA provides additional detail on the methodology. The EPA solicits 
comment on the assumptions and uncertainties included in this analysis.

  Table XII-2--Estimated Total Monetary Values of Changes in Human Health Outcomes for ELG Options (Millions of
                                          2018$) Compared to Baseline a
----------------------------------------------------------------------------------------------------------------
                                                                      Reduced
                                                   Reduced lead       mercury     Reduced cancer
        Discount rate (%)             Option       exposure for    exposure for     cases from         Total
                                                   children \b\      children         arsenic
----------------------------------------------------------------------------------------------------------------
3...............................               1           $0.00          -$0.31           $0.00          -$0.31
                                               2           -0.01           -2.84            0.00           -2.85
                                               3            0.00           -2.85            0.00           -2.85
                                               4            0.00           -1.49            0.00           -1.49
7...............................               1            0.00           -0.06            0.00           -0.06
                                               2            0.00           -0.57            0.00          -0.575
                                               3            0.00           -0.58            0.00           -0.58
                                               4            0.00           -0.30            0.00           -0.30
----------------------------------------------------------------------------------------------------------------
\a\ Negative values represent forgone benefits.
\b\ ``$0.00'' indicates that monetary values are greater than -$0.01 million but less than $0.00 million.
  Benefits to children from exposure to lead range from -$9.1 to $0.7 thousands per year, using a 3 percent
  discount rate, and from -$2.1 to $0.2 thousands, using a 7 percent discount rate.

[[Page 64656]]

    The EPA also estimated changes in bladder cancer incidence from the 
use and consumption of drinking water contaminated with total 
trihalomethanes (TTHMs) derived from changes in pollutant loadings of 
bromide associated with the four regulatory options in today's proposal 
relative to the baseline. This qualitative relationship between bladder 
cancer and bromide demonstrates the relative size of the benefit to 
other benefits associated with this proposal. Should this analysis be 
used to justify an economically significant rulemaking, the EPA intends 
to peer review the analysis consistent with OMB's Information Quality 
Bulletin for Peer Review. That review would include robust examination 
of the strengths and limitations of the methods and an exploration of 
the sensitivity of the results to the assumptions made. If the analysis 
is designated a highly influential scientific assessment (HISA), one 
way the EPA may seek such a review is via the EPA's Science Advisory 
Board (SAB), which is particularly well suited to provide a peer review 
of HISAs. The EPA's SAB is a statutorily established committee with a 
broad mandate to provide advice and recommendations to the Agency on 
scientific and technical matters.
    The EPA estimated changes in cancer risks within populations served 
by drinking water treatment facilities with intakes on surface waters 
influenced by bromide discharges from steam electric facilities. The 
EPA used Safe Drinking Water Information System (SDWIS) and US Census 
data to estimate the exposed population. The EPA used estimates of 
changes in waterbody-specific bromide concentrations and estimates of 
drinking water treatment facility-specific TTHM concentrations to 
calculate potential changes in exposure to TTHM and associated adverse 
health outcomes.
    The TTHM MCL is set higher than the health-based trihalomethane 
Maximum Contaminant Level Goals (MCLGs) in order to balance protection 
from human health risks from DBP exposure with the need for adequate 
disinfection to control human health risks from microbial pathogens. 
Actions that reduce TTHM levels below the MCL can therefore further 
reduce human health risk. The EPA's analysis quantifies the human 
health effects associated with incremental changes between the MCL and 
the MCLG. Recent TTHM compliance monitoring data indicate that the 
drinking water treatment facilities contributing most significantly to 
the total estimated benefits for the regulatory options have TTHM 
levels below the MCL but in excess of the MCLGs for trihalomethanes.
    Table XII-3 summarizes the estimated monetary value of estimated 
changes in bromide-related human health outcomes from modeled surface 
water quality improvements under Options 2, 3, and 4 or degradation 
under Option 1. As described in Chapter 4 of the BCA Report, 
approximately 90 percent of these benefits derive from a small number 
of steam electric facilities (6 facilities under Option 2, 7 facilities 
under Option 3, and 17 facilities under Option 4). Bromide reduction 
benefits under Options 2 and 3 derive from estimated facility 
participation in the VIP.
    The formation of TTHM in a particular water treatment system is a 
function of several site-specific factors, including chlorine, bromine, 
organic carbon, temperature, pH and the system residence time. The EPA 
did not collect site-specific information on these factors at each 
potentially affected drinking water treatment facility. Instead, the 
EPA conducted a site-based analysis which only addresses the estimated 
site-specific changes in bromides. To account for the changes in TTHM, 
and subsequently bladder cancer incidence, using only the estimated 
site-specific changes in bromides, the EPA used the national 
relationship from Regli et al (2015).\93\ Using this relationship the 
analysis held all of the other site-specific factors constant at the 
measured values at the approximately 200 drinking water treatment 
facilities in that study. Thus, while the national changes in TTHM and 
bladder cancer incidence given estimated changes in bromide are the 
EPA's best estimate on a nationwide basis, the EPA cautions that for 
any specific drinking water treatment facility the estimates could be 
over- or underestimated. The EPA solicits comment on the extent to 
which uncertainty surrounding site-specific estimated benefits 
associated with bromides reductions impact the national estimates 
presented in this analysis, as well as data that would assist the EPA 
in evaluating this uncertainty. Additional details and uncertainties of 
this analysis are provided in Chapter 4 of the BCA Report.
---------------------------------------------------------------------------

    \93\ Regli, S., Chen, J., Messner, M., Elovitz, M.S., 
Letkiewicz, F.J., Pegram, R.A., Pepping, T.J., Richardson, S.D., 
Wright, J.M., 2015. Estimating potential increased bladder cancer 
risk due to increased bromide concentrations in sources of 
disinfected drinking waters. Environmental Science & Technology, 
49(22), 13094-13102.

    Table XII-3--Estimated Human Health Benefits of Changing Bromide
          Discharges Under the ELG Options Compared to Baseline
        [Million of 2018$, three and seven percent discount rate]
------------------------------------------------------------------------
                                              Annualized human health
                                              benefits over 27 years
                                          (millions of 2018$, discounted
            Regulatory option                      to 2020) \a\
                                         -------------------------------
                                            3% Discount     7% Discount
                                               rate            rate
------------------------------------------------------------------------
Option 1................................          -$0.36          -$0.23
Option 2................................           37.61           24.21
Option 3................................           42.57           27.48
Option 4................................           84.32           54.30
------------------------------------------------------------------------
\a\ The analysis accounts for the persisting health effects (up until
  2121) from changes in TTHM exposure during the period of analysis
  (2021-2047).

[[Page 64657]]

2. Changes in Surface Water Quality
    The EPA evaluated whether the regulatory options in today's 
proposal would alter aquatic habitats and human welfare by changing 
concentrations of harmful pollutants such as arsenic, cadmium, 
chromium, copper, lead, mercury, nickel, selenium, zinc, nitrogen, 
phosphorus, and suspended sediment relative to the baseline. As a 
result, the usability of some of the waters for recreation relative to 
baseline discharge conditions could change under each option, thereby 
affecting recreational users. Changes in pollutant loadings can also 
change the attractiveness of waters usable for recreation by making 
recreational trips more or less enjoyable. The regulatory options may 
also change nonuse values stemming from bequest, altruism, and 
existence motivations. Individuals may value water quality maintenance, 
ecosystem protection, and healthy species populations independent of 
any use of those attributes.
    The EPA uses a water quality index (WQI) to translate water quality 
measurements, gathered for multiple parameters that are indicative of 
various aspects of water quality, into a single numerical indicator 
that reflects achievement of quality consistent with the suitability 
for certain uses. The WQI includes seven parameters: Dissolved oxygen, 
biochemical oxygen demand, fecal coliform, total nitrogen, total 
phosphorus, TSS, and one aggregate subindex for toxics. The EPA modeled 
changes in four of these parameters, and held the remaining parameters 
(dissolved oxygen, biochemical oxygen demand, and fecal coliform) 
constant for the purposes of this analysis. Table XII-4 summarizes 
water quality change ranges relative to the baseline under the four 
regulatory options. Under Options 1 through 3, 78 to 84 percent of 
potentially affected reaches have a negative change in the WQI. Another 
16 to 22 percent of reaches show no change under these options. Under 
Option 4, 61 percent of reaches would experience a negative change in 
the WQI, and another 12 percent of reaches show no change.

      Table XII-4--Estimated Ranges of Water Quality Changes Under Regulatory Options Compared to Baseline
----------------------------------------------------------------------------------------------------------------
                                                                                                    [Delta]WQI
                Regulatory option                     Minimum         Maximum         Median       interquartile
                                                  [Delta]WQI \a\    [Delta]WQI      [Delta]WQI         range
----------------------------------------------------------------------------------------------------------------
Option 1........................................           -5.29            0.00        -0.00102         0.01000
Option 2........................................           -2.95            1.30        -0.00047         0.00168
Option 3........................................           -2.95            1.30        -0.00023         0.00078
Option 4........................................           -2.62            1.31        -0.00002         0.00125
----------------------------------------------------------------------------------------------------------------
\a\ Negative changes in WQI values indicate degrading water quality.

    The EPA estimated the change in monetized benefit values using the 
same meta-regressions of surface water valuation studies used in the 
benefit analysis for the 2015 rule. The meta-regressions quantify 
average household WTP for incremental improvements in surface water 
quality. This WTP is the maximum amount of money a person is willing to 
give up to obtain an improvement in water quality. Chapter 6 of the BCA 
provides additional detail on the valuation methodology. Overall, 
Option 1 results in water quality degradation, which is reflected in 
negative annual household WTP values ranging from -$0.11 to -$0.62. 
Under Options 2, 3, and 4, the net water quality improvements 
(accounting for all increases and decreases of pollutant loadings) 
result in positive net benefits to households affected by water quality 
changes from the regulatory options proposed. The estimated annual 
household WTP for water quality changes ranges from $0.10 to $0.56 for 
Option 2, $0.16 to $0.87 for Option 3, and $0.19 to $1.04 for Option 4.
    Table XII-5 presents annualized total WTP values for water quality 
changes associated with modified metal (arsenic, cadmium, chromium, 
copper, lead, mercury, zinc, and nickel), non-metal (selenium), 
nutrient (phosphorus and nitrogen), and sediment pollutant discharges 
to the approximately 10,393 reach miles affected by the regulatory 
options in this proposal. An estimated 85 million households reside in 
Census block groups within 100 miles of affected reaches. The central 
tendency estimate of the total annualized benefits of water quality 
changes for Option 2 range from $14.3 million (7 percent discount rate) 
to $16.7 million (3 percent discount rate).

                    Table XII-5--Estimated Total Willingness-To-Pay for Water Quality Changes (Millions 2018$) Compared to Baseline a
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                Number of              3% Discount rate                       7% Discount rate
                                                                 affected  -----------------------------------------------------------------------------
                      Regulatory option                         households
                                                                (millions)      Low        Central        High         Low        Central        High
--------------------------------------------------------------------------------------------------------------------------------------------------------
Option 1.....................................................         85.2       -$10.0       -$12.5       -$55.5        -$8.6       -$10.9       -$48.1
Option 2.....................................................         86.9         11.8         16.7         65.6         10.1         14.3         56.1
Option 3.....................................................         84.6         16.3         22.5         90.7         14.0         19.4         77.8
Option 4.....................................................         86.5         19.8         27.3        110.2         17.0         23.6         94.6
--------------------------------------------------------------------------------------------------------------------------------------------------------
\a\ Negative values represent forgone benefits and positive values represent realized benefits.

3. Effects on Threatened and Endangered Species
    To assess the potential for impacts on T&E species (both aquatic 
and terrestrial) relative to the 2015 baseline, the EPA analyzed the 
overlap between waters expected to change their wildlife WQC exceedance 
status under a particular option and the known critical habitat 
locations of high-vulnerability T&E species. The EPA examined the life 
history traits of potentially affected T&E species and categorized them 
by potential for population impacts due to surface water quality 
changes. Chapter 7

[[Page 64658]]

of the BCA Report provides additional detail on the methodology. The 
EPA determined that there are 24 species whose known critical habitat 
overlaps with surface waters that may be affected by the proposed 
options when compared to the baseline, including three fish species, 
two amphibian and reptile species, one bird species, 17 clam and mussel 
species, and one snail species. Six of these species have known 
critical habitat overlapping surface waters that are expected to see 
reduced exceedances of NRWQC under proposed Options 2, 3, or 4, while 
23 species (including 5 species that may see reduced exceedances of 
NRWQC under proposed Options 2, 3, or 4, depending on habitat location) 
have known critical habitat overlapping surface waters that may see 
increased exceedances of NRWQC under one or more of the proposed 
options. Under Option 2, there are two species whose known critical 
habitat overlaps with surface waters that may see reduced exceedances 
of NRWQC, and 12 species whose known critical habitat overlaps with 
surface waters that may see increased exceedances of NRWQC. Option 1 is 
expected to result in increased exceedances of NRWQC across all habitat 
locations. Principal sources of uncertainty include the specifics of 
how these proposed options will impact threatened and endangered 
species, exact spatial distribution of the species, and additional 
species of concern not considered.
4. Changes in Benefits From Marketing of Coal Combustion Residuals
    The proposed rule options could affect the ability of steam 
electric facilities to market coal combustion byproducts for beneficial 
use by converting from wet to dry handling of BA. In particular, the 
EPA evaluated the potential effects from changes in marketability of BA 
as a substitute for sand and gravel in fill applications. Among the 
regulatory options considered for this proposal, EPA estimates that 
only Option 2 would affect the quantity of BA handled wet when compared 
to the baseline, and for that option the estimated increase in BA 
handled wet is small (total of 310,671 tons per year at 20 facilities). 
Given these small changes and the uncertainty associated with 
projecting facility-specific changes in marketed ash, the EPA chose not 
to monetize this benefit category in the analysis of the proposed 
regulatory options. See Chapter 2 in the BCA report for additional 
details.
5. Changes in Dredging Costs
    The proposed regulatory options would affect discharge loadings of 
various categories of pollutants, including TSS, thereby changing the 
rate of sediment deposition to affected waterbodies, including 
navigable waterways and reservoirs that require dredging for 
maintenance.
    Navigable waterways, including rivers, lakes, bays, shipping 
channels and harbors, are an integral part of the United States 
transportation network. They are prone to reduced functionality due to 
sediment build-up, which can reduce the navigable depth and width of 
the waterway. In many cases, costly periodic dredging is necessary to 
keep them passable. Reservoirs serve many functions, including storage 
of drinking and irrigation water supplies, flood control, hydropower 
supply, and recreation. Streams can carry sediment into reservoirs, 
where it can settle and cause buildup of silt layers over time. 
Sedimentation reduces reservoir capacity and the useful life of 
reservoirs unless measures such as dredging are taken to reclaim 
capacity. Chapter 10 of the BCA provides additional detail on the 
methodology.
    The EPA expects that Option 4 would provide cost savings ranging 
from $0.48 million (7 percent discount rate) to $0.72 million (3 
percent discount rate) by reducing required dredging maintenance for 
both navigable waterways and reservoirs. Estimated increases in 
sediment loadings under Options 1, 2, and 3 would result in cost 
increases. Cost increases range from $0.05 million to $0.09 million for 
Option 1, $0.12 million to $0.21 million for Option 2, and $0.04 
million to $0.07 million for Option 3.
6. Changes in Air-Related Effects
    The EPA expects the proposed options to affect air pollution 
through three main mechanisms: (1) Changes in auxiliary electricity use 
by steam electric facilities to operate wastewater treatment, ash 
handling, and other systems that the EPA predicts facilities would use 
under each proposed option; (2) changes in transportation-related air 
emissions due to changes in trucking of CCR waste to landfills; and (3) 
change in the profile of electricity generation due to the relatively 
higher or lower costs to generate electricity at steam electric 
facilities incurring compliance costs under the proposed options.
    Changes in the electricity generation profile can increase or 
decrease air pollutant emissions because emission factors vary for 
different types of electric boilers. For this analysis, the changes in 
air emissions are based on the change in dispatch of generation units 
as projected by IPM V6 given the overlaying of costs for complying with 
the proposed options onto steam electric boilers' production costs. As 
discussed in Section VIII of this preamble, the IPM V6 analysis 
accounts for the effects of other regulations on the electric power 
sector.
    The EPA evaluated potential effects resulting from net changes in 
air emissions of three pollutants: NOX, SO2, and 
CO2. NOX and SOX are precursors to 
fine particles sized 2.5 microns and smaller (PM2.5), this 
air pollutant causes a variety of adverse health effects including 
premature death, non-fatal heart attacks, hospital admissions, 
emergency department visits, upper and lower respiratory symptoms, 
acute bronchitis, aggravated asthma, lost work days, and acute 
respiratory symptoms. CO2 is a key greenhouse gas linked to 
a wide range of domestic effects.\94\
---------------------------------------------------------------------------

    \94\ U.S. EPA. Integrated Science Assessment (ISA) for 
Particulate Matter (Final Report, Dec 2009). U.S. Environmental 
Protection Agency, Washington, DC, EPA/600/R-08/139F, 2009.
---------------------------------------------------------------------------

    The EPA used domestic social cost of carbon estimates to value 
changes in CO2 emissions (SC-CO2). The Agency 
quantified changes in emissions of PM2.5 precursors, 
NOX, and SO2. To map those emission changes to 
air quality changes across the country, air quality modeling is needed. 
Prior to this proposal, the EPA's modeling capacity was fully allocated 
to supporting other regulatory and policy efforts.
    Table XII-6 shows the changes in emissions of NOX, 
SO2, and CO2 based on the estimated increases in 
electricity generation (see Table VIII-3) for options 2 and 4 (the two 
regulatory options that the EPA analyzed for these increased emission 
effects). Table XII-7 shows the total annualized monetary values 
associated with changes in emissions of CO2 for options 2 
and 4. All total monetary values are negative, indicating that the 
proposed rule results in net forgone CO2-related benefits 
when compared to the baseline. While not monetized, additional forgone 
benefits associated with PM2.5 would also occur. The 
majority of the forgone benefits are due to changes in the profile of 
electricity generation. Smaller shares of the changes in total benefits 
are attributable to changes in energy use to operate wastewater 
treatment systems. Benefits from changes in trucking emissions are 
negligible. The EPA did not analyze benefits from changes in air 
emissions for Options 1 and 3 but instead extrapolated values by 
scaling air-related benefits under Option 2 in

[[Page 64659]]

proportion to the total social costs of each option. Chapter 8 of the 
BCA Report provides additional details on the analysis of air-related 
benefits.

                     Table XII-6--Estimated Changes in Air Emissions Compared to Baseline a
----------------------------------------------------------------------------------------------------------------
                                                                    CO2 (metric
           Regulatory option              Category of emissions     tons/year)      NOX (tons/      SO2 (tons/
                                                                                       year)           year)
----------------------------------------------------------------------------------------------------------------
Option 2..............................  Electricity generation b       5,656,000           4,650           4,930
                                         c.
                                        Trucking................            -490               0               0
                                        Energy use b c..........         -44,080             -32             -54
                                                                 -----------------------------------------------
                                           Total \d\............       5,611,000           4,620           4,870
rrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrr
Option 4..............................  Electricity generation b       1,244,000           1,900           1,020
                                         e.
                                        Trucking................           1,440               1               0
                                        Energy use b e..........          59,320              31              20
                                                                 -----------------------------------------------
                                           Total \d\............       1,305,000           1,940           1,040
----------------------------------------------------------------------------------------------------------------
\a\ Negative values represent emission reductions.
\b\ Estimated changes in emissions shown for 2028-2032 based on the estimated increase in electricity generation
  of 0.3% for Option 2 and 0.1% for Option 4.
\c\ Option 2 estimates are based on the IPM sensitivity analysis scenario that includes the ACE rule in the
  baseline (IPM-ACE).
\d\ Values may not sum to the total due to independent rounding.
\e\ Option 4 estimates are based on IPM analysis scenario that does not include the ACE rule in the baseline.

   Table XII-7--Estimated Annualized Benefits From Changes in CO2 Air Emissions (Millions; 2018$) Compared to
                                                   Baseline a
----------------------------------------------------------------------------------------------------------------
                                                                                    3% Discount     7% Discount
               Regulatory option                      Category of emissions            rate            rate
----------------------------------------------------------------------------------------------------------------
Option 2......................................  Electricity generation \b\......          -$32.0           -$5.2
                                                Trucking........................             0.0             0.0
                                                Energy use \b\..................             0.4             0.1
                                                                                 -------------------------------
                                                   Total \c\....................           -31.6            -5.2
                                                                                 -------------------------------
Option 4......................................  Electricity generation \d\......            -4.3            -0.8
                                                Trucking........................             0.0             0.0
                                                Energy use \d\..................            -0.5             0.0
                                                                                 -------------------------------
                                                   Total \c\....................            -4.8            -0.9
----------------------------------------------------------------------------------------------------------------
\a\ Negative values represent forgone benefits.
\b\ Option 2 estimates are based on the IPM sensitivity analysis scenario that includes the ACE rule in the
  baseline (IPM-ACE).
\c\ Values may not sum to the total due to independent rounding.
\d\ Option 4 estimates are based on IPM analysis scenario that does not include the ACE rule in the baseline.

7. Benefits From Changes in Water Withdrawals
    Steam electric facilities use water for handling BA and operating 
wet FGD scrubbers. By reducing water used in sluicing operations or 
prompting the recycling of water in FGD wastewater treatment systems, 
Option 4 is expected to reduce water withdrawals from surface waters, 
whereas proposed Options 1, 2, and 3 are expected to increase water 
withdrawals from surface waterbodies. Option 2 is also expected to 
increase water withdrawal from aquifers. Using the same methodology 
used for the 2015 rule, the EPA estimated the monetary value of 
increased ground water withdrawals based on increased costs of ground 
water supply. For each relevant facility, the EPA multiplied the 
increase in ground water withdrawal (in gallons per year) by water 
costs of about $1,192 per acre-foot. Chapter 9 of the BCA Report 
provides the details of this analysis. The EPA estimates the changes in 
annualized benefits of increased ground water withdrawals are less than 
$0.2 million annually. Due to data limitations, the EPA was not able to 
estimate the monetary value of changes in surface water withdrawals. 
Chapter 9 of the BCA Report and Section 7 of the Supplemental TDD 
provide additional details on the estimated changes in surface water 
withdrawals.

C. Total Monetized Benefits

    Using the analysis approach described above, the EPA estimated the 
total monetary value of annual benefits of the proposed rule for all 
monetized categories. Table XII-8 and Table XII-9 summarize the total 
annualized monetary value of social welfare effects using 3 percent and 
7 percent discount rates, respectively. The total monetary value of 
benefits under Option 2 range from $14.8 million to $68.5 million using 
a 3 percent discount rate and from $28.4 million to $74.4 million using 
a 7 percent discount rate.

[[Page 64660]]

                                             Table XII-8--Summary of Total Annualized Benefits at 3 Percent
                                                                   [Millions; 2018$] a
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                    Option 1                      Option 2                   Option 3                   Option 4
           Benefit category            -----------------------------------------------------------------------------------------------------------------
                                           Low        Mid        High      Low      Mid      High     Low      Mid      High     Low      Mid      High
--------------------------------------------------------------------------------------------------------------------------------------------------------
Human Health \d\......................               -$0.7
                                                     $34.8
                                                     $39.7
                                                     $82.8
    Changes in IQ losses in children
     from exposure to lead \b\........                <0.0
                                                      <0.0
                                                      <0.0
                                                      <0.0
    Changes in IQ losses in children
     from exposure to mercury.........                -0.3
                                                     -2.84
                                                     -2.85
                                                     -1.49
    Reduced cancer risk from DBPs in
     drinking water...................                -0.4
                                                      37.6
                                                      42.6
                                                      84.3
                                       -----------------------------------------------------------------------------------------------------------------
Ecological Conditions and Recreational     -$10.0     -$12.5     -$55.5    $11.8    $16.7    $65.6    $16.3    $22.5    $90.7    $19.8    $27.3   $110.2
 Uses Changes.........................
    Use and nonuse values for water         -10.0      -12.5      -55.5     11.8     16.7     65.6     16.3     22.5     90.7     19.8     27.3    110.2
     quality changes..................
Market and Productivity \d\...........       -0.1       -0.1       -0.1     -0.2     -0.2     -0.2     -0.1     -0.1     -0.1      0.6      0.6      0.7
    Changes in dredging costs.........       -0.1       -0.1       -0.1     -0.1     -0.2     -0.2     -0.1     -0.1     -0.1      0.6      0.6      0.7
                                       -----------------------------------------------------------------------------------------------------------------
    Reduced water withdrawals \b\.....                $0.0
                                                     <$0.0
                                                      $0.0
                                                      $0.0
Air-related effects...................               -30.3
                                                     -31.6
                                                     -20.9
                                                      -4.8
    Changes in CO2 air emissions \c\..               -30.3
                                                     -31.6
                                                     -20.9
                                                      -4.8
                                       -----------------------------------------------------------------------------------------------------------------
        Total \d\.....................     -$41.0     -$43.6     -$86.6    $14.8    $19.6    $68.5    $35.1    $41.3   $109.4    $98.4   $105.9   $188.9
--------------------------------------------------------------------------------------------------------------------------------------------------------
\a\ Negative values represent forgone benefits and positive values represent realized benefits.
\b\ ``<$0.0'' indicates that monetary values are greater than -$0.1 million but less than $0.00 million.
\c\ The EPA estimated the air-related benefits for Option 2 using the IPM sensitivity analysis scenario that includes the ACE rule in the baseline (IPM-
  ACE). EPA extrapolated estimates for Options 1 and 3 air-related benefits from the estimate for Option 2 that is based on IPM-ACE outputs. The values
  for Option 4 air-related benefits were estimated using the IPM analysis scenario that does not include the ACE rule in the baseline.
\d\ Values for individual benefit categories may not sum to the total due to independent rounding.

                                             Table XII-9--Summary of Total Annualized Benefits at 7 Percent
                                                                   [Millions; 2018$] a
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                    Option 1                      Option 2                   Option 3                   Option 4
           Benefit category            -----------------------------------------------------------------------------------------------------------------
                                           Low        Mid        High      Low      Mid      High     Low      Mid      High     Low      Mid      High
--------------------------------------------------------------------------------------------------------------------------------------------------------
Human Health \d\......................               -$0.3
                                                     $23.6
                                                     $26.9
                                                     $54.0
    Changes in IQ losses in children
     from exposure to lead \b\........                <0.0
                                                      <0.0
                                                      <0.0
                                                      <0.0
    Changes in IQ losses in children
     from exposure to mercury.........                -0.1
                                                      -0.6
                                                      -0.6
                                                      -0.3
    Reduced cancer risk from DBPs in
     drinking water...................                -0.2
                                                      24.2
                                                      27.5
                                                      54.3
                                       -----------------------------------------------------------------------------------------------------------------
Ecological Conditions and Recreational      -$8.6     -$10.9     -$48.1    $10.1    $14.3    $56.1    $14.0    $19.4    $77.8    $17.0    $23.6    $94.6
 Uses Changes.........................
    Use and nonuse values for water          -8.6      -10.9      -48.1     10.1     14.3     56.1     14.0     19.4     77.8     17.0     23.6     94.6
     quality changes..................
Market and Productivity \d\...........       -0.1       -0.1       -0.1     -0.1     -0.2     -0.2      0.0     -0.1     -0.1      0.5      0.5      0.7
    Changes in dredging costs.........       -0.1       -0.1       -0.1     -0.1     -0.1     -0.2      0.0     -0.1     -0.1      0.5      0.5      0.7
                                       -----------------------------------------------------------------------------------------------------------------
    Reduced water withdrawals \b\.....                $0.0
                                                     <$0.0
                                                      $0.0
                                                      $0.0
Air-related Effects...................                -4.8
                                                      -5.2
                                                      -3.7
                                                      -0.9
    Changes in CO2 air emissions \c\..                -4.8
                                                      -5.2
                                                      -3.7
                                                      -0.9
                                       -----------------------------------------------------------------------------------------------------------------
        Total \d\.....................     -$13.7     -$16.0     -$53.3    $28.4    $32.6    $74.4    $37.1    $42.5   $100.9    $70.6    $77.2   $148.4
--------------------------------------------------------------------------------------------------------------------------------------------------------
\a\ Negative values represent forgone benefits and positive values represent realized benefits.
\b\ ``<$0.0'' indicates that monetary values are greater than -$0.1 million but less than $0.00 million.
\c\ The EPA estimated the air-related benefits for Option 2 using the IPM sensitivity analysis scenario that includes the ACE rule in the baseline (IPM-
  ACE). EPA extrapolated estimates for Options 1 and 3 air-related benefits from the estimate for Option 2 that is based on IPM-ACE outputs. The values
  for Option 4 air-related benefits were estimated using the IPM analysis scenario that does not include the ACE rule in the baseline.
\d\ Values for individual benefit categories may not sum to the total due to independent rounding.

D. Unmonetized Benefits

    The monetary value of the proposed rule's effects on social welfare 
does not account for all effects of the proposed options because, as 
described above, the EPA is unable to monetize some categories. 
Examples of effects not reflected in these monetary estimates include 
health and other effects from changes in NOX and 
SO2 air emissions; changes in certain non-cancer health 
risks (e.g., effects of cadmium on kidney functions and bone density); 
impacts of pollutant load changes on threatened and endangered species 
habitat; and ash marketing changes. The BCA Report discusses changes in 
these effects qualitatively, indicating their potential magnitude where 
possible.

XIII. Development of Effluent Limitations and Standards

A. FGD Wastewater

    The proposed rule contains new numeric effluent limitations and 
pretreatment standards that apply to discharges of FGD wastewater at 
existing sources.\95\ The EPA is

[[Page 64661]]

proposing several sets of effluent limitations and pretreatment 
standards for FGD wastewater discharges; the specific set of 
limitations that would apply to any particular facility are determined 
by which subcategory the facility falls within, or whether it chooses 
to participate in the voluntary incentives program. The EPA developed 
the numeric effluent limitations and pretreatment standards in this 
proposed rule using long-term average effluent values and variability 
factors that account for variations in performance at well-operated 
facilities that employ the technologies that constitute the bases for 
control. The EPA's methodology for derivation of limitations in ELGs is 
longstanding and has been upheld in court. See, e.g., Chem. Mfrs. Ass'n 
v. EPA, 870 F.2d 177 (5th Cir. 1989); Nat'l Wildlife Fed'n v. EPA, 286 
F.3d 554 (D.C. Cir. 2002). The EPA establishes the final effluent 
limitations and standards as ``daily maximums'' and ``maximums for 
monthly averages.'' Definitions provided in 40 CFR 122.2 state that the 
daily maximum limitation is the ``highest allowable `daily discharge' 
'' and the maximum for monthly average limitation is the ``highest 
allowable average of `daily discharges' over a calendar month, 
calculated as the sum of all `daily discharges' measured during a 
calendar month divided by the number of `daily discharges' measured 
during that month.'' Daily discharges are defined to be the `` 
`discharge of a pollutant' measured during a calendar day or any 24-
hour period that reasonably represents the calendar day for purposes of 
sampling.''
---------------------------------------------------------------------------

    \95\ Effluent limitations for boilers with nameplate capacity of 
50 MW or smaller and for boilers that will retire by December 31, 
2028, are not discussed in this section. The proposed limitations 
for these generating units are based on the previously established 
BPT limitations on TSS.
---------------------------------------------------------------------------

1. Overview of the Limitations and Standards
    The EPA's objective in establishing daily maximum limitations is to 
restrict the discharges on a daily basis at a level that is achievable 
for a facility that designs and operates its treatment to achieve the 
long-term average performance that the EPA's statistical analyses show 
the BAT/PSES technology can attain (i.e., the mean of the underlying 
statistical distribution of daily effluent values). The EPA recognizes 
that variability around the long-term average occurs during normal 
operations. This variability means that facilities occasionally may 
discharge at a level that is higher than the long-term average, and at 
other times will discharge at a level that is lower than the long-term 
average. To allow for these possibly higher daily discharges and 
provide an upper bound for the allowable concentration of pollutants 
that may be discharged, while still targeting achievement of the long-
term average, the EPA has established the daily maximum limitation. A 
facility consistently discharging at a level near the daily maximum 
limitation would be symptomatic of a facility that is not operating its 
treatment to achieve the long-term average. Targeting treatment to 
achieve the daily limitation, rather than the long-term average, is not 
consistent with the capability of the BAT/PSES technology basis and may 
result in values that periodically exceed the limitations due to 
routine variability in treated effluent.
    The EPA's objective in establishing monthly average limitations is 
to provide an additional restriction to help ensure that facilities 
target their average discharges to achieve the long-term average. The 
monthly average limitation requires dischargers to provide ongoing 
control, on a monthly basis, that supplements controls imposed by the 
daily maximum limitation. In order to meet the monthly average 
limitation, a facility must counterbalance a value near the daily 
maximum limitation with one or more values well below the daily maximum 
limitation.
2. Criteria Used To Select Data
    In developing effluent limitations guidelines and standards for any 
industry, the EPA qualitatively reviews all the data before selecting 
data that represents proper operation of the technology that forms the 
basis for the limitations. The EPA typically uses four criteria to 
assess the data. The first criterion requires that the facilities have 
the model treatment technology identified as a candidate basis for 
effluent limitations (e.g., chemical precipitation with LRTR) and 
demonstrate consistently diligent and optimal operation. Application of 
this criterion typically eliminates any facility with treatment other 
than the model technology. The EPA generally determines whether a 
facility meets this criterion based upon site visits, discussions with 
facility management, and/or comparison to the characteristics, 
operation, and performance of treatment systems at other facilities. 
The EPA reviews available information to determine whether data 
submitted were representative of normal operating conditions for the 
facility and equipment. As a result of this review, the EPA typically 
excludes the data in developing the limitations when the facility has 
not optimized the performance of its treatment system.
    A second criterion generally requires that the influents and 
effluents from the treatment components represent typical wastewater 
from the industry, without incompatible wastewater from other sources. 
Application of this criterion results in the EPA selecting those 
facilities where the commingled wastewaters did not result in 
substantial dilution, unequalized slug loads resulting in frequent 
upsets and/or overloads, more concentrated wastewaters, or wastewaters 
with different types of pollutants than those generated by the 
wastestream for which the EPA is proposing effluent limitations and 
pretreatment standards.
    A third criterion typically ensures that the pollutants are present 
in the influent at sufficient concentrations to evaluate treatment 
effectiveness. If a data set for a pollutant shows that the pollutant 
was not present at a treatable concentration at sufficient frequency 
(e.g., the pollutant was below the level of detection in all influent 
samples), the EPA excludes the data for that pollutant at that facility 
when calculating the limitations.
    A fourth criterion typically requires that the data are valid and 
appropriate for their intended use (e.g., the data must be analyzed 
with a sufficiently sensitive method). Also, the EPA does not use data 
associated with periods of treatment upsets because these data would 
not reflect the performance from well-designed and well-operated 
treatment systems. In applying the fourth criterion, the EPA may 
evaluate the pollutant concentrations, analytical methods and the 
associated quality control/quality assurance data, flow values, mass 
loading, facility logs, test reports, and other available information. 
As part of this evaluation, the EPA reviews the process or treatment 
conditions that may have resulted in extreme values (high and low). As 
a consequence of this review, the EPA may exclude data associated with 
certain time periods or other data outliers that reflect poor 
performance or analytical anomalies by an otherwise well-operated site.
    The fourth criterion also is applied in the EPA's review of data 
corresponding to the initial commissioning period for treatment systems 
(and startup periods for pilot test equipment). Most industries incur 
commissioning periods during the adjustment period associated with 
installing new treatment systems. During this acclimation and 
optimization process, the effluent concentration values tend to be 
highly variable with occasional extreme values (high and low). This 
occurs because the treatment system typically requires

[[Page 64662]]

some ``tuning'' as the facility staff and equipment and chemical 
vendors work to determine the optimum chemical addition locations and 
dosages, vessel hydraulic residence times, internal treatment system 
recycle flows (e.g., filter backwash frequency, duration and flow rate, 
return flows between treatment system components), and other 
operational conditions including clarifier sludge wasting protocols. It 
may also take time for treatment system operators to gain expertise on 
operating the new treatment system, which also contributes to treatment 
system variability during the commissioning period. After this initial 
adjustment period, the systems should operate at steady state with 
relatively low variability around a long-term average over many years. 
Because commissioning periods typically reflect one-time operating 
conditions unique to the first time the treatment system begins 
operation, the EPA generally excludes such data in developing the 
limitations.\96\
---------------------------------------------------------------------------

    \96\ Examples of conditions that are typically unique to the 
initial commissioning period include operator unfamiliarity or 
inexperience with the system and how to optimize its performance; 
wastewater flow rates that differ significantly from engineering 
design, altering hydraulic residence times, chemical contact times, 
and/or clarifier overflow rates, and potentially causing large 
changes in planned chemical dosage rates or the need to substitute 
alternative chemical additives; equipment malfunctions; fluctuating 
wastewater flow rates or other dynamic conditions (i.e., not steady 
state operation); and initial purging of contaminants associated 
with installation of the treatment system, such as initial leaching 
from coatings, adhesives, and susceptible metal components. These 
conditions differ from those associated with the restart of an 
already-commissioned treatment system, such as may occur from a 
treatment system that has undergone either short or extended 
duration shutdown.
---------------------------------------------------------------------------

3. Data Used To Calculate Limitations and Standards
    The Supplemental TDD provides a description of the data and 
methodology used to develop long-term averages, variability factors, 
and limitations and standards for this proposed rule. The effluent 
limitations and pretreatment standards for the low utilization 
subcategory and high flow subcategory are based on chemical 
precipitation. The derivation of the limitations for these 
subcategories and the data used are described in Section 13 of the 2015 
TDD. The new limitations and pretreatment standards proposed today for 
facilities not in those subcategories and for the voluntary incentives 
plan were derived from a statistical analysis of effluent data 
collected by facilities during extended testing of the LRTR technology 
and membrane filtration technology, respectively. The duration of the 
test programs at these facilities spanned from approximately one month 
for membranes to more than a year for LRTR, enabling the EPA to 
evaluate long-term performance of these technologies under conditions 
that can contribute to influent variability, including varying power 
demand, changes in coal suppliers, and changes in operation of the air 
pollution control system. The tests occurred over different seasons of 
the year and demonstrate that the technologies operate effectively 
under varying climate conditions.
    During the development of these new limitations and pretreatment 
standards, the EPA identified certain data that warranted exclusion 
because: (1) The samples were analyzed using a method that is not 
sensitive enough to reliably quantify the pollutants present (e.g., use 
of EPA Method 245.1 to measure the concentration of mercury in effluent 
samples); (2) the analytical results were identified as questionable 
due to quality control issues associated with the laboratory analysis 
or sample collection, or were analytical anomalies; (3) the samples 
were collected prior to steady-state operating condition and do not 
represent BAT/PSES level of performance; (4) the samples were collected 
during a period where influent composition did not reflect the FGD 
wastewater (e.g., untreated FGD wastewater was mixed with large volume 
of non-FGD wastewater prior to the treatment system); (5) the treatment 
system was operating in a manner that does not represent BAT/PSES level 
of performance; or (6) the samples were collected from a location that 
is not representative of treated effluent.
4. Long-Term Averages and Effluent Limitations and Standards for FGD 
Wastewater
    Table XIV-1 presents the proposed effluent limitations and 
standards for FGD wastewater. For comparison, the table also presents 
the long-term average treatment performance calculated for each 
parameter. Due to routine variability in treated effluent, a power 
facility that targets discharging its wastewater at a level near the 
values of the daily maximum limitation or the monthly average 
limitation may periodically experience values exceeding the 
limitations. For this reason, the EPA recommends that facilities design 
and operate the treatment system to achieve the long-term average for 
the model technology. In doing so, a system that is designed and 
operated to achieve the BAT/PSES level of control would meet the 
limitations.
    The EPA expects that facilities will be able to meet their effluent 
limitations or standards at all times. If an exceedance is caused by an 
upset condition, the facility would have an affirmative defense to an 
enforcement action if the requirements of 40 CFR 122.41(n) are met. 
Exceedances caused by a design or operational deficiency, however, are 
indications that the facility's performance does not represent the 
appropriate level of control. For these proposed limitations and 
pretreatment standards, the EPA proposes to determine that such 
exceedances can be controlled by diligent process and wastewater 
treatment system operational practices, such as regular monitoring of 
influent and effluent wastewater characteristics and adjusting dosage 
rates for chemical additives to target effluent performance for 
regulated pollutants at the long-term average concentration for the 
BAT/PSES technology. Additionally, some facilities may need to upgrade 
or replace existing treatment systems to ensure that the treatment 
system is designed to achieve performance that targets the effluent 
concentrations at the long-term average. This is consistent with the 
EPA's costing approach and its engineering judgment, developed over 
years of evaluating wastewater treatment processes for steam electric 
facilities and other industrial sectors. The EPA recognizes that some 
dischargers, including those that are operating technologies 
representing the technology basis for the proposed rule, may need to 
improve their treatment systems, process controls, and/or treatment 
system operations in order to consistently meet the proposed effluent 
limitations and pretreatment standards. This is consistent with the 
CWA, which requires that BAT/PSES discharge limitations and standards 
reflect the best available technology economically achievable.
    See Section 8 of the Supplemental TDD for more information about 
the calculation of the limitations and pretreatment standards presented 
in the tables below.

[[Page 64663]]

   Table XIV-1--Long-Term Averages and Effluent Limitations and Pretreatment Standards for FGD Wastewater for
                                          Existing Sources (BAT/PSES) a
----------------------------------------------------------------------------------------------------------------
                                                                                                      Monthly
              Subcategory                       Pollutant            Long-term    Daily  maximum      average
                                                                      average        limitation     limitation
----------------------------------------------------------------------------------------------------------------
Requirements for all facilities not in  Arsenic ([mu]g/L).......             5.1              18               9
 the VIP or subcategories specified     Mercury (ng/L)..........            13.5              85              31
 below (BAT & PSES).                    Nitrate/nitrite as N (mg/            2.6             4.6             3.2
                                         L).
                                        Selenium ([mu]g/L)......            16.6              76              31
Voluntary Incentives Program for FGD    Arsenic ([mu]g/L).......         \b\ 5.0           \c\ 5           (\d\)
 Wastewater (BAT only).                 Mercury (ng/L)..........             5.1              21               9
                                        Nitrate/nitrite as N (mg/            0.4             1.1             0.6
                                         L).
                                        Selenium ([mu]g/L)......             5.0              21              11
                                        Bromide (mg/L)..........            0.16             0.6             0.3
                                        TDS (mg/L)..............              88             351             156
Low utilization subcategory--AND--High  Arsenic ([mu]g/L).......            5.98              11               8
 flow subcategory (BAT & PSES).         Mercury (ng/L)..........             159             788             356
----------------------------------------------------------------------------------------------------------------
\a\ BAT effluent limitations for boilers with nameplate capacity of 50 MW or smaller, and boilers that will
  retire by December 31, 2028, are based on the previously established BPT limitations on TSS and are not shown
  in this table. The BAT effluent limitations for TSS for these retiring boilers is daily maximum of 100 mg/L;
  monthly average of 30 mg/L.
\b\ Long-term average is the arithmetic mean of the quantitation limitations since all observations were not
  detected.
\c\ Limitation is set equal to the quantitation limit for the data evaluated.
\d\ Monthly average limitation is not established when the daily maximum limitation is based on the quantitation
  limit.

    The EPA notes that while some limitations are higher than 
corresponding limits in the 2015 rule, in other cases limitations of 
additional pollutants or lower limitations for pollutants regulated in 
the 2015 rule have also been calculated. The EPA solicits comment on 
the demonstrated ability or inability of existing systems to meet the 
limitations in this proposal, the costs associated with modifying 
existing systems or with modifying the operation of existing systems to 
meet these limits, and whether any existing systems with demonstrated 
issues meeting these limits would be best addressed through FDF 
variances or through subcategorization. Furthermore, should the EPA 
determine subcategorization of facilities with existing FGD treatment 
systems is warranted, the EPA solicits comment on what limitations 
should apply to those facilities, including whether the 2015 rule 
limits would be appropriate for such facilities.

B. BA Transport Water Limitations

1. Maximum 10 Percent 30-Day Rolling Average Purge Rate
    In contrast to the limitations estimated for specific pollutants 
above, the EPA is proposing a pollutant discharge allowance in the form 
of a maximum percentage purge rate for BA transport water. To develop 
this allowance, the EPA first collected data on the discharge needs of 
the model treatment technology (high recycle rate systems) to maintain 
water chemistry or water balance.\97\ EPRI (2016) presents discharge 
data from seven currently operating wet BA transport water systems at 
six facilities. These facilities were able to recycle most or all BA 
transport water from these seven systems, resulting in discharges of 
between zero and two percent of the system volume. The EPA's goal in 
establishing the proposed purge rate was to provide an allowance to 
address the challenges that would be incorporated in the EPRI (2016) 
data, as well as infrequent precipitation and maintenance events, the 
EPA also needed a way to account for such infrequent events. While EPRI 
(2016) noted that infrequent discharges happened at some facilities, it 
did not include such events in its discharge calculations. As a result, 
EPA looked to EPRI (2018), which presents hypothetical maximum 
discharge volumes and the estimated frequency associated with such 
infrequent events for currently operating wet BA systems.\98\ Since 
these calculations are only estimates, the EPA solicits data on actual 
precipitation and maintenance-related discharges. For purposes of 
calculating the allowance percentage associated with such infrequent 
events, the EPA divided the discharge associated with an estimated 
maintenance and precipitation event by the volume of the system, and 
then averaged the resulting percent over 30 days.
---------------------------------------------------------------------------

    \97\ Although the technology basis includes dry handling, the 
limitation is based on the necessary purge volumes of a wet, high 
recycle rate BA system.
    \98\ Although presented in EPRI (2018), the EPA did not consider 
events such as pipe leaks, as these would not be reflective of 
proper system operation (see DCN SE06920).
---------------------------------------------------------------------------

    Finally, the EPA added each reported regular discharge percent from 
EPRI (2016) to the averaged infrequent discharge percent under four 
scenarios: (1) With no infrequent discharge event, (2) with only a 
precipitation-related discharge event, (3) with only a maintenance-
related discharge event, and (4) with both a precipitation-related and 
maintenance-related discharge event. These potential discharge needs 
are reported in Table XIV-2 below. Consistent with the statistical 
approach used to develop limitations and pretreatment standards for 
individual pollutants, the EPA selected a 95th percentile of 10 percent 
of total system volume as representative of the 30-day rolling 
average.\99\
---------------------------------------------------------------------------

    \99\ While there were further decimal points for the actual 
calculated 95th percentile, the EPA notes that 10 percent is two 
significant digits, consistent with the limitations for FGD 
wastewater pollutants. Furthermore, a 10 percent volumetric limit 
will be easier for implementation by the permitting authority as it 
results in a simple decimal point movement for calculations.

[[Page 64664]]

                                  Table XIV-2--30-Day Rolling Average Discharge Volume as a Percent of System Volume a
--------------------------------------------------------------------------------------------------------------------------------------------------------
    Infrequent discharge needs as estimated in EPRI (2018)     Regular discharge needs to maintain water chemistry and/or water balance as characterized
--------------------------------------------------------------                                       in EPRI (2016)
                                                     30-Day   ------------------------------------------------------------------------------------------
       Type of infrequent discharge event           rolling                                                                     Facility F-- Facility F--
                                                    average     Facility A   Facility B   Facility C   Facility D   Facility E    System 1     System 2
                                                          (%)          (%)          (%)          (%)          (%)          (%)          (%)          (%)
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                       0.1          0.0          1.0          0.0          0.8          2.0          2.0
Neither Event...................................          0.0          0.1          0.0          1.0          0.0          0.8          2.0          2.0
Precipitation Only..............................          5.4          5.5          5.4          6.4          5.4          6.2          7.4          7.4
Maintenance Only................................          3.3          3.4          3.3          4.3          3.3          4.1          5.3          5.3
Both Events.....................................          8.7          8.8          8.7          9.7          8.7          9.5         10.7         10.7
--------------------------------------------------------------------------------------------------------------------------------------------------------
\a\ These estimates sum actual/reported, facility-specific regular discharge needs with varying combinations of hypothetically estimated, infrequent
  discharge needs.

    The EPA recognizes that some facilities may need to improve their 
equipment, process controls, and/or operations to consistently meet the 
zero discharge standard established by the 2015 rule. However, with the 
discharge allowance included in this proposed rule, the EPA expects 
that facilities would be able to avoid these costs in most 
circumstances. For example, in the table above, only when the Facility 
F systems experience both high-end precipitation- and maintenance-
related discharge events could the required discharge potentially 
exceed the 30-day rolling average of 10 percent. This is consistent 
with the CWA, which requires that BAT/PSES discharge limitations and 
standards reflect the best available technology economically 
achievable. For further discussion of costs associated with managing a 
fully-closed-loop system, see Section 5 of the Supplemental TDD.
2. Best Management Practices Plan
    As described in Section VII of this preamble, one of the regulatory 
options presented in today's proposed rule would require a subcategory 
of facilities discharging BA transport water and having low MWh 
production to develop and implement a BMP plan to recirculate BA 
transport water back to the BA handling system (see Section VII of this 
preamble for more details).
    The proposed BMP provisions would require applicable facilities to 
develop a plan to minimize the discharge of pollutants by recycling as 
much BA transport water as practicable back to the BA handling system. 
For example, if a facility could recycle 80 percent of its BA transport 
water for a few thousand dollars, but recycling 81 percent would 
require the installation of a multi-million dollar system, the former 
would be practicable, but the latter would not.\100\ After determining 
the amount of BA transport water that could be easily recycled and 
developing a facility-specific BMP plan, facilities are required to 
implement the plan and annually review and revise the plan as 
necessary.
---------------------------------------------------------------------------

    \100\ The limit of what is practicable at a facility may change 
drastically after making changes to comply with the CCR rule. For 
instance, if a facility closes its unlined surface impoundment and 
installs a remote MDS, the recycle rate that is practicable may 
approach that of the high recycle systems that the EPA used to 
establish BAT for units not falling into this subcategory.
---------------------------------------------------------------------------

XIV. Regulatory Implementation

A. Implementation of the Limitations and Standards

    The requirements in this rule apply to discharges from steam 
electric facilities through incorporation into NPDES permits issued by 
the EPA or by authorized states under Section 402 of the Act, and 
through local pretreatment programs under Section 307 of the Act. 
Permits or control mechanisms issued after this rule's effective date 
must incorporate the ELGs, as applicable. Also, under CWA section 510, 
states can require effluent limitations under state law as long as they 
are no less stringent than the requirements of this rule. Finally, in 
addition to requiring application of the technology-based ELGs in this 
rule, CWA section 301(b)(1)(C) requires the permitting authority to 
impose more stringent effluent limitations, as necessary, to meet 
applicable water quality standards.
1. Timing
    The direct discharge limitations proposed in this rule would apply 
only when implemented in an NPDES permit issued to a discharger. Under 
the CWA, the permitting authority must incorporate these ELGs into 
NPDES permits as a floor or a minimum level of control. The proposed 
rule would allow a permitting authority to determine a date when the 
new effluent limitations for FGD wastewater and BA transport water will 
apply to a given discharger. As proposed, the permitting authority 
would make these effluent limitations applicable on or after November 
1, 2020. For any final effluent limitation that is specified to become 
applicable after November 1, 2020, the specified date must be as soon 
as possible, but in no case later than December 31, 2023, for BA 
transport water, or December 31, 2025, for FGD wastewater. For 
dischargers choosing to meet the voluntary incentives program effluent 
limitations for FGD wastewater, the date for meeting those limitations 
is December 31, 2028.
    For FGD wastewater and BA transport water from boilers retiring by 
2028, the proposed BAT limitations would apply on the date that a 
permit is issued to a discharger. The proposed rule does not build in 
an implementation period for meeting these limitations, as the BAT 
limitation on TSS is equal to the previously promulgated BPT limitation 
on TSS. Pretreatment standards are self-implementing, meaning they 
apply directly, without the need for a permit. As defined by the 
statute, the pretreatment standards for existing sources must be met by 
three years after the effective date of any final rule.
    Regardless of when a facility's NPDES permit is ready for renewal, 
the EPA recommends that each facility immediately begin evaluating how 
it intends to comply with the requirements of any final rule. In cases 
where significant changes in operation are appropriate, the EPA 
recommends that the facility discuss such changes with its permitting 
authority and evaluate appropriate steps and a timeline for the changes 
as soon as a final rule is issued, even prior to the permit renewal 
process.
    In cases where a facility's final NPDES permit is issued before 
these ELGs are finalized, and includes limitations for BA transport 
water and/or FGD wastewater from the 2015 rule, EPA recommends such a 
permit be reopened as soon as practicable, and modified consistent with 
any new rule provisions.
    For permits that are issued on or after November 1, 2020, the 
permitting

[[Page 64665]]

authority would determine the earliest possible date that the facility 
can meet the limitations (but in no case later than December 31, 2023, 
for BA transport water or December 31, 2025, for FGD wastewater), and 
apply the proposed limitations as of that date (BPT limitations or the 
facility's other applicable permit limitations would apply until such 
date).
    As proposed, the ``as soon as possible'' date determined by the 
permitting authority is November 1, 2020, unless the permitting 
authority determines another date after receiving facility-specific 
information submitted by the discharger.\101\ EPA is not proposing to 
revise the specified factors that the permitting authority must 
consider in determining the as soon as possible date. Assuming that the 
permitting authority receives relevant, site-specific information from 
each discharger, in order to determine what date is ``as soon as 
possible'' within the implementation period, the factors established in 
the 2015 rule are:
---------------------------------------------------------------------------

    \101\ Information in the record indicates that most facilities 
should be able to complete all steps to implement changes needed to 
comply with proposed BA transport water requirements within 15-23 
months, and the FGD wastewater requirements within 26 to 34 months.
---------------------------------------------------------------------------

    (a) Time to expeditiously plan (including to raise capital), 
design, procure, and install equipment to comply with the requirements 
of the final rule.\102\
---------------------------------------------------------------------------

    \102\ Cooperatives and municipalities presented information to 
the EPA suggesting that obtaining financing for these projects can 
be more challenging than for investor-owned utilities. Under this 
factor, permitting authorities may consider whether the type and 
size of owner and difficulty in obtaining the expected financing 
might warrant additional flexibility up to the ``no later than'' 
date.
---------------------------------------------------------------------------

    (b) Changes being made or planned at the facility in response to 
greenhouse gas regulations for new or existing fossil fuel-fired 
facilities under the Clean Air Act, as well as regulations for the 
disposal of coal combustion residuals under subtitle D of the Resource 
Conservation and Recovery Act.
    (c) For FGD wastewater requirements only, an initial commissioning 
period to optimize the installed equipment.
    (d) Other factors as appropriate.
    The EPA proposes to clarify that the discharger must provide 
relevant, site-specific information for consideration of these factors 
by the permitting authority. Environmental groups informed the EPA that 
facilities had filed permit applications for, and states had granted, 
delayed applicability dates based on information about a facility other 
than the one being permitted. This was not the intent of the 2015 rule, 
and the EPA solicits comment on other potential misunderstandings of 
the factors presented in the 2015 rule that may have caused confusion 
or led to misunderstandings.
    As specified in factor (b), the permitting authority must also 
consider scheduling for installation of equipment, which includes a 
consideration of facility changes planned or being made to comply with 
certain other key rules that affect the steam electric power generating 
industry. As specified in factor (c), for the FGD wastewater 
requirements only, the permitting authority must consider whether it is 
appropriate to allow more time for implementation in order to ensure 
that the facility has appropriate time to optimize any relevant 
technologies.
    The ``as soon as possible'' date determined by the permitting 
authority may or may not be different for each wastestream. The 
permitting authority should provide a well-documented justification of 
how it determined the ``as soon as possible'' date in the fact sheet or 
administrative record for the permit. If the permitting authority 
determines a date later than November 1, 2020, the justification should 
explain why allowing additional time to meet the proposed limitations 
is appropriate, and why the discharger cannot meet the effluent 
limitations as of November 1, 2020. In cases where the facility is 
already operating the proposed BAT technology basis for a specific 
wastestream (e.g., dry FA handling system), operates the majority of 
the proposed BAT technology basis (e.g., FGD chemical precipitation and 
biological treatment, without sulfide addition), or expects that 
relevant treatment and process changes would be in place prior to 
November 1, 2020 (for example due to the CCR rule), it would not 
usually be appropriate to allow additional time beyond that date. 
Regardless, in all cases, the permitting authority would make clear in 
the permit by what date the facility must meet the proposed 
limitations, and that date, as proposed, would be no later than 
December 31, 2023, for BA transport water, or December 31, 2025, for 
FGD wastewater.
    Where a discharger chooses to participate in the VIP and be subject 
to effluent limitations for FGD wastewater based on membranes, the 
permitting authority must allow the facility up to December 31, 2028, 
to meet those limitations. Again, the permit must make clear that the 
facility must meet the limitations by December 31, 2028.
2. Implementation for the Low Utilization Subcategory
    The EPA is proposing to establish a new subcategory for low 
utilization boilers with net generation below 876,000 MWh per year. The 
EIA defines net generation as, ``The amount of gross generation less 
the electrical energy consumed at the generating station(s) for station 
service or auxiliaries. Note: Electricity required for pumping at 
pumped-storage plants is regarded as electricity for station service 
and is deducted from gross generation.'' \103\ Unlike other 
subcategories, which often require that a facility possess some static 
characteristic (e.g., less than 50 MW nameplate capacity), the proposed 
low utilization subcategory is based on the fluctuating net generation 
reported annually to the EIA. Thus, the EPA is clarifying how 
permitting authorities can determine whether a facility qualifies for 
this subcategorization, and how limitations for boilers in this 
subcategorization are to be implemented.
---------------------------------------------------------------------------

    \103\ See EIA Glossary, available online at: https://www.eia.gov/tools/glossary/index.php?id=N.
---------------------------------------------------------------------------

a. Determining Boiler Net Generation
    When a facility seeks to have limitations for one or more 
subcategorized boilers incorporated into its permit, the EPA is 
proposing that the facility provide the permitting authority its 
calculation of the average of the most recent two calendar years of net 
generation for that boiler(s). A facility wishing to seek this 
subcategory, must operate below this threshold before the latest 
implementation dates, but a permitting authority should also refrain 
from establishing a ``no later than date'' which would restrict a 
facility from demonstrating two years of reduced net generation. This 
average should primarily be collected and calculated using data 
developed for reporting to the EIA, since using net generation 
information already collected for the EIA will both eliminate the 
potentially unnecessary paperwork burden of a separate information 
gathering and calculations and allow the permitting authority to more 
easily verify the accuracy of the reported values. If it is necessary 
for a facility to apportion facility-wide energy consumption not 
specifically attributable to individual boilers, the facility must 
apportion this consumption proportionally, by boiler nameplate 
capacity, unless it adequately documents a sufficient rationale for an 
alternate apportionment. The use of a two-year average will ensure that 
a low utilization boiler responding to a single extreme demand event in 
one year (e.g.,

[[Page 64666]]

unexpectedly high peak demand in summer or winter) can still qualify 
for this subcategory if its average net generation over the two years 
remains below 876,000 MWh. Furthermore, the facility must annually 
provide the permitting authority an updated two-year average net 
generation for each subcategorized boiler within 60 days of submitting 
annual net generation information to the EIA.
b. Tiering Limitations
    In cases where a facility seeks to have limitations for this 
subcategory incorporated into its permit, the EPA is proposing that a 
permitting authority incorporate two additional features. First, the 
EPA is proposing that the limitations for this subcategory be included 
as the first of two sets of limitations. The second set of limitations 
would be those applicable to the rest of the steam electric generation 
point source category. Second, the EPA is proposing that these tiered 
limits have a two-year timeframe to be implemented for a facility 
exceeding the two-year net generation requirements as measured per 
calendar year. For example, if a facility reported it exceeded a two-
year average net generation of 876,000 MWh for a unit, it would have 
two years before discharges of FGD wastewater and BA transport water 
would henceforth be subject to the second tier of limitations.\104\ 
Application of the second tier would preclude future use of the low 
utilization subcategory.
---------------------------------------------------------------------------

    \104\ Once a facility installs the capital equipment needed to 
meet the second tier of limitations, O&M costs will be proportional 
to the utilization of the boiler, and thus would no longer result in 
disproportionate costs.
---------------------------------------------------------------------------

    These tiered limitations would ensure that, if a boiler that 
qualified for this subcategorization changes its operation such that it 
no longer qualifies, it would be automatically subject to the second 
set of limitations. An automatic feature makes sense for several 
reasons. Tiered limitations are beneficial to the regulated facility 
because they provide certainty that the facility would not be 
considered in violation of its permit initially, when exceeding the 
required net generation, nor subsequently, during the two-year 
timeframe over which it has to meet the second tier of effluent 
limitations. Two years is also consistent with the engineering 
documents provided to the EPA for the installation of the appropriate 
technologies. Tiered limitations are beneficial to the state because 
they avoid the potentially onerous permit modification process and its 
burden to the permitting authority. Finally, tiered limitations are 
beneficial to the environment because they ensure a timely transition 
to more stringent limitations as soon as the reason for the less 
stringent limitations (disproportionate cost) is gone. The EPA solicits 
comment on the inclusion of tiered limitations.
3. Addressing Withdrawn or Delayed Retirement
    Since the 2015 rule, the EPA has learned of several instances when 
facilities have withdrawn or delayed retirement announcements for coal-
fired boilers and facilities. These instances can be grouped into two 
categories. First, some delays were involuntary, resulting from orders 
issued by the Department of Energy (DOE) or Public Utility Commissions 
(PUCs). The remaining announcements were withdrawn or delayed 
voluntarily due to changed circumstances. While both the voluntary and 
involuntary changes to announced retirements were infrequent, the EPA 
acknowledges that such changes will necessarily impact a facility's 
status with regard to some of the new subcategories in today's 
proposal. These situations are discussed below. For further information 
on announced retirements, see DCN SE07207.
a. Involuntary Retirement Delays
    At least five facilities with announced retirement dates had those 
dates involuntarily delayed as a result of the DOE issuing orders under 
Section 202(c) of the Federal Power Act, or a PUC issuing a reliability 
must-run agreement. Such involuntary operations have raised questions 
about the conflict between legal obligations to produce electricity and 
legal obligations under environmental statutes.\105\ Today's proposal 
would subcategorize low utilization boilers and boilers retiring by 
2028, subjecting those subcategories to less stringent limitations. 
However, both utilization and retirement could be impacted by 
involuntary orders and agreements. Thus, the EPA proposes a savings 
clause that would be included in all permits where a facility seeks 
limitations under one of these two subcategories. Such a savings clause 
would protect a facility which involuntarily fails to qualify for the 
subcategory for low utilization or retiring boilers, and would allow 
that facility to prove that, but for the order or agreement, it would 
have qualified for the subcategory. The EPA solicits comment on whether 
the proposed savings clause is broad enough to address all scenarios 
that may result in a mandatory order to operate a boiler.
---------------------------------------------------------------------------

    \105\ Moeller, James. 2013. Clean air vs. electric reliability: 
The case of the Potomac River Generating Station. September. 
Available online at: https://scholarlycommons.law.wlu.edu/cgi/viewcontent.cgi?referer=https://www.google.com/&httpsredir=1&article=1077&context=jece.
---------------------------------------------------------------------------

b. Voluntary Retirement Withdrawals and Delays
    Units at five facilities with announced retirement dates had those 
dates voluntarily withdrawn or delayed due to changed situations, 
including market conditions, unavailability of natural gas pipelines, 
changes in environmental regulations, and sale of the facility. Like 
the involuntary retirement delays discussed in the section above, these 
situations could impact a facility's qualification for the proposed 
subcategories for low utilization boilers and boilers retiring by 2028. 
Unlike the involuntary retirement delays, these voluntary delays and 
withdrawals can be accounted for through the normal integrated resource 
planning process. Thus, the EPA does not propose a similar savings 
clause for such units. Instead, a facility should carefully plan its 
implementation of the ELGs.

B. Reporting and Recordkeeping Requirements

    This proposal includes five new reporting and recordkeeping 
standards. First, the EPA is proposing a reporting and recordkeeping 
standard for facilities operating high recycle rate BA systems. The EPA 
is proposing that such facilities submit the calculation of the primary 
active wetted BA system volume, which means the maximum volumetric 
capacity of BA transport water in all piping (including recirculation 
piping) and primary tanks of a wet bottom ash system, excluding the 
volumes of installed spares, redundancies, maintenance tanks, other 
secondary bottom ash system equipment, and non-bottom ash transport 
systems that may direct process water to the bottom ash system. This 
ensures that the permitting authority can verify the volume of 
discharge allowed for a high recycle rate system. The EPA solicits 
comment on the specific components of the BA transport water system 
that should be included and/or excluded from the calculation of primary 
active wetted BA system volume.
    Second, the EPA is proposing a reporting and recordkeeping 
requirement for facilities seeking subcategorization of low utilization 
boilers. The EPA is proposing that, as part of any permit renewal or 
re-opening, such facilities submit a calculation of the two-year 
average net generation for each applicable boiler to

[[Page 64667]]

the permitting authority, including underlying information. Once any 
limitations of this subcategory are applicable, the EPA is proposing 
that such a facility annually recertify that the boiler continues to 
meet the requirements of this subcategory, along with an updated two-
year average net generation calculation and information for each 
applicable boiler. As proposed, if a boiler exceeds the MWh 
requirements of this subcategory, no further recordkeeping or reporting 
would be required, as this boiler would be treated the same as the rest 
of the steam electric point source category after the necessary 
treatment equipment was installed and operational at the end of two 
years.
    Third, as described in Section VII.C.2, facilities with boilers 
that qualify for the low-utilization subcategory and that discharge BA 
transport water, would be required to develop and implement a BMP plan 
to minimize the discharge of pollutants by recycling as much BA 
transport water as practicable back to the BA handling system. As part 
of any permit renewal or any re-opening, such facilities would need to 
submit their facility-specific plan (certified that it meets the 
proposed requirements of 40 CFR 423.13(k)(3)) along with a 
certification that the plan is being implemented. For each permit 
renewal, the plan and PE certification should be updated and provided 
to the permitting authority.
    Fourth, the EPA is proposing reporting and recordkeeping 
requirements for facilities seeking subcategorization for a boiler(s) 
retiring by December 31, 2028. The EPA is proposing that, as part of 
the permit renewal or re-opening, which are when a facility would make 
this request, such facilities submit a one-time certification to the 
permitting authority stating the date of expected retirement from the 
combustion of coal, and provide a citation to any filing, integrated 
resource plan, or other documentation in support of that date. This 
citation is meant to provide the permitting authority further evidence 
that a boiler will, in fact, cease the production of electricity by 
that date.
    Finally, the EPA is proposing reporting and recordkeeping 
requirements for facilities invoking the proposed savings clause. The 
EPA is proposing that such facilities must demonstrate that a boiler 
would have qualified for the subcategory at issue, if not for the 
emergency order issued by the DOE under Section 202(c) of the Federal 
Power Act or PUC reliability must-run agreement. Furthermore, the EPA 
is proposing to require a copy of such order or agreement as an 
attachment to the submission.

C. Site-Specific Water Quality-Based Effluent Limitations

    The EPA regulations at 40 CFR 122.44(d)(1) require that each NPDES 
permit shall include any requirements, in addition to or more stringent 
than effluent limitations guidelines 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. Furthermore, 
those same regulations require that limitations must control all 
pollutants, or pollutant parameters (either conventional, 
nonconventional, or toxic pollutants) which the Director determines are 
or may be discharged at a level which 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.
    Bromide was discussed in the preamble to the 2015 rule 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 on bromide or TDS would be appropriate for FGD wastewater 
discharges from steam electric facilities 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.
    The EPA is not proposing additional limitations on bromide for FGD 
wastewater beyond the removals that might be accomplished by facilities 
choosing to implement the VIP limitations, though the EPA is soliciting 
comment on the three potential bromide-specific sub-options presented 
in Section VII of this preamble. The record continues to suggest that 
state permitting authorities should consider establishing water 
quality-based effluent limitations that are protective of populations 
served by downstream drinking water treatment facilities. As described 
in Section XII, the analysis of changes in human health benefits 
associated with changes in bromide discharges are concentrated at a 
small number of sites. This supports the EPA's determination that 
potential discharges are best addressed using site-specific, water 
quality-based effluent limitations established by permitting 
authorities for the small number of steam electric facilities that may 
impact downstream drinking water treatment facilities.

XV. Related Acts of Congress, Executive Orders, and Agency Initiatives

A. Executive Orders 12866 (Regulatory Planning and Review) and 13563 
(Improving Regulation and Regulatory Review)

    This proposed rule is an economically significant regulatory action 
that was submitted to the Office of Management and Budget (OMB) for 
review. Any changes made in response to OMB recommendations have been 
documented in the docket. The EPA prepared an analysis of the potential 
social costs and benefits associated with this action. This analysis is 
contained in Chapter 13 of the BCA, available in the docket. The 
analysis in the BCA builds on compliance costs and certain other 
assumptions regarding compliance years discussed in the RIA to estimate 
the incremental social costs and benefits of the four proposed options 
relative to the baseline. Analyzing the options against the baseline 
enables the Agency to characterize the incremental impact of ELG 
revisions proposed by this action.
    Table XV-1 presents the annualized value of the social costs and 
benefits over 27 years and discounted using a three percent discount 
rate as compared to the updated baseline. Table XV-2 presents 
annualized values using a seven percent discount rate. In both tables, 
negative costs indicate avoided costs (i.e., cost savings) and negative 
benefits indicate forgone benefits.

            Table XV-1--Total Monetized Annualized Benefits and Costs of Proposed Regulatory Options
                                [Million of 2018$, three percent discount rate] a
----------------------------------------------------------------------------------------------------------------
                                                                          Total monetized benefits c d e
                Regulatory option                  Total social  -----------------------------------------------
                                                      costs b      Low estimate    Mid estimate    High estimate
----------------------------------------------------------------------------------------------------------------
Option 1........................................         -$130.6          -$41.0          -$43.6          -$86.6
Option 2........................................          -136.3            14.8            19.6            68.5

[[Page 64668]]

 
Option 3........................................           -90.1            35.1            41.3           109.4
Option 4........................................            11.9            98.4           105.9           188.9
----------------------------------------------------------------------------------------------------------------
\a\ All social costs and benefits were annualized over 27 years using a 3% discount rate. Negative costs
  indicate avoided costs and negative benefits indicate forgone benefits. All estimates are rounded to one
  decimal point, so figures may not sum due to independent rounding.
\b\ Total social costs are compliance costs to facilities accounting for the timing those costs are incurred.
\c\ Total monetized benefits exclude other benefits discussed qualitatively.
\d\ The EPA estimated the air-related benefits for Option 2 using the IPM sensitivity analysis scenario that
  includes the ACE rule in the baseline (IPM-ACE). EPA extrapolated estimates for Options 1 and 3 air-related
  benefits from the estimate for Option 2 that is based on IPM-ACE outputs. The values for Option 4 air-related
  benefits were estimated using the IPM analysis scenario that does not include the ACE rule in the baseline.
  See Chapter 8 in the BCA for details). The EPA estimated air-related benefits for Options 1 and 3 by
  multiplying the total costs for each option by the ratio of [air-related benefits/total social costs] for
  Option 2. The EPA did not monetize benefits of changes in NOX and SO2 emissions and associated changes in
  PM2.5 levels for any option.
\e\ The EPA estimated use and nonuse values for water quality improvements using two different meta-regression
  models of WTP. One model provides the low and high bounds while a different model provides a central estimate
  (included in this table under the mid-range column). For this reason, the mid benefit estimate differs from
  the midpoint of the benefits range. For details, see Chapter 5 in the BCA.

            Table XV-2--Total Monetized Annualized Benefits and Costs of Proposed Regulatory Options
                                [Million of 2018$, seven percent discount rate] a
----------------------------------------------------------------------------------------------------------------
                                                                          Total monetized benefits c d e
                Regulatory option                  Total social  -----------------------------------------------
                                                     costs \b\     Low estimate    Mid estimate    High estimate
----------------------------------------------------------------------------------------------------------------
Option 1........................................         -$154.0          -$13.7          -$16.0          -$53.3
Option 2........................................          -166.2            28.4            32.6            74.4
Option 3........................................          -119.5            37.1            42.5           100.9
Option 4........................................           -27.3            70.6            77.2           148.4
----------------------------------------------------------------------------------------------------------------
\a\ All social costs and benefits were annualized over 27 years using a 7% discount rate. Negative costs
  indicate avoided costs and negative benefits indicate forgone benefits. All estimates are rounded to one
  decimal point, so figures may not sum due to independent rounding.
\b\ Total social costs are compliance costs to facilities accounting for the timing those costs are incurred.
\c\ Total monetized benefits exclude other benefits discussed qualitatively.
\d\ The EPA estimated the air-related benefits for Option 2 using the IPM sensitivity analysis scenario that
  includes the ACE rule in the baseline (IPM-ACE). EPA extrapolated estimates for Options 1 and 3 air-related
  benefits from the estimate for Option 2 that is based on IPM-ACE outputs. The values for Option 4 air-related
  benefits were estimated using the IPM analysis scenario that does not include the ACE rule in the baseline.
  See Chapter 8 in the BCA for details). The EPA estimated air-related benefits for Options 1 and 3 by
  multiplying the total costs for each option by the ratio of [air-related benefits/total social costs] for
  Option 2. The EPA did not monetize benefits of changes in NOX and SO2 emissions and associated changes in
  PM2.5 levels for any option.
\e\ The EPA estimated use and nonuse values for water quality improvements using two different meta-regression
  models of WTP. One model provides the low and high bounds while a different model provides a central estimate
  (included in this table under the mid-range column). For this reason, the mid benefit estimate differs from
  the midpoint of the benefits range. For details, see Chapter 5 in the BCA.

B. Executive Order 13771 (Reducing Regulation and Controlling 
Regulatory Costs)

    The proposed regulatory options would be an Executive Order 13771 
deregulatory action. Details on the estimated cost savings of the 
regulatory options are located in the RIA, and in Tables XV-1 and XV-2 
above.

C. Paperwork Reduction Act

    OMB has previously approved the information collection requirements 
contained in the existing regulations 40 CFR part 423 under the 
provisions of the Paperwork Reduction Act, 44 U.S.C. 3501 et seq. and 
has assigned OMB control number 2040-0281. The OMB control numbers for 
the EPA's regulations in 40 CFR are listed in 40 CFR part 9.
    The EPA estimated small changes in monitoring costs at steam 
electric facilities under the regulatory options presented in today's 
proposal relative to the baseline. As proposed, these changes would 
apply to facilities for which the proposed subcategories are 
applicable. In some cases, in lieu of these monitoring requirements, 
facilities would have additional paperwork burden such as that 
associated with certifications and applicable BMP plans. See Section 
VII of this preamble. However, some facilities would also realize 
savings, relative to the baseline, by no longer monitoring pollutants 
for some subcategories of boilers (and because their applicable 
limitations and standards are based on less costly technologies). The 
EPA projects that the burden associated with the new proposed paperwork 
requirements would be largely off-set by the reduced burden associated 
with less monitoring; therefore, the Agency projects that the proposal 
would have no net effect on the burden of the approved information 
collection requirements. With respect to permitting authorities, based 
on the information in its record, the EPA also does not expect any of 
the regulatory options in today's proposal to increase or decrease 
their burden. The proposed options would not change permit application 
requirements or the associated review; they would not affect the number 
of permits issued to steam electric facilities; nor would the options 
change the efforts involved in developing or reviewing such permits. 
Accordingly, the EPA estimated no net change (i.e., no increase or 
decrease) in the cost burden to federal or state governments or 
dischargers associated with any of the regulatory options in this 
proposed rule.

D. Regulatory Flexibility Act

    The Regulatory Flexibility Act (RFA) generally requires an agency 
to prepare a regulatory flexibility analysis of any rule subject to 
notice-and-comment

[[Page 64669]]

rulemaking requirements under the Administrative Procedure Act or any 
other statute, unless the agency certifies that the rule will not have 
a significant economic impact on a substantial number of small 
entities. Small entities include small businesses, small organizations, 
and small governmental jurisdictions.
    The Agency certifies that this action will not have a significant 
economic impact on a substantial number of small entities under the 
RFA. The basis for this finding is documented in Chapter 8 of the RIA, 
included in the docket and summarized below.
    The EPA estimates that 243 to 478 entities own steam electric 
facilities to which the regulatory options would apply, of which 79 to 
127 are small. These small ownership entities own a total of 139 steam 
electric facilities. The EPA considered the impacts of the regulatory 
options presented in this proposal on small businesses using a cost-to-
revenue test. The analysis compares the cost of implementing controls 
for BA and FGD wastewater under the four regulatory options to those 
under the baseline (which reflects the 2015 rule as explained in 
Section V of this preamble). Small entities estimated to incur 
compliance costs exceeding one or more of the one percent and three 
percent impact thresholds were identified as potentially incurring a 
significant impact. The EPA's analysis shows that four small entities 
(municipalities) are expected to incur costs equal to or greater than 
one percent of revenue to meet the 2015 rule; for two of these 
municipalities, the costs to meet the 2015 rule exceed three percent of 
revenue. Cost savings provided under the regulatory options reduce the 
impacts on these small entities to varying degrees. Option 2 has the 
greatest mitigating effect on small entities, reducing to 2 the number 
of small entities incurring costs equal to or greater than one percent 
of revenue, and to 1 the entities with costs greater than three percent 
of revenue. Options 1, 3, and 4 have similar mitigating effects, with 
one fewer small entity incurring costs equal to or greater than one 
percent of revenue. The number of small entities exceeding either the 
one or three percent impact threshold in the baseline is small in the 
absolute and represents small percentages of the total estimated number 
of small entities; the cost savings provided by the regulatory options 
further support the EPA's finding of no significant impact on a 
substantial number of small entities (No SISNOSE).

E. Unfunded Mandates Reform Act

    Title II of the Unfunded Mandates Reform Act of 1995 (UMRA), 2 
U.S.C. 1531-1538, requires federal agencies, unless otherwise 
prohibited by law, to assess the effects of their regulatory actions on 
state, local, and tribal governments, and the private sector. An action 
contains a federal mandate if it may result in expenditures of $100 
million or more (annually, adjusted for inflation) for state, local, 
and tribal governments, in the aggregate, or the private sector in any 
one year ($160 million in 2018).
    The EPA finds that this action is not subject to the requirements 
of UMRA section 203 because the expenditures are less than $160 million 
or more in any one year. As detailed in Chapter 9 of the RIA, for its 
assessment of the impact of potential changes in compliance 
requirements on small governments (governments for populations of less 
than 50,000), the EPA estimated the changes in costs for compliance 
with the regulatory options relative to the baseline for different 
categories of entities. All four regulatory options presented in this 
proposal result in lower compliance costs (cost savings) when compared 
to the baseline. Compared to $44.1 million in the baseline, the Agency 
estimates that the change in maximum cost in any one year to state, 
local, or tribal governments range from -$23.5 million under Option 1 
to -$6.0 million under Option 4, with an incremental cost for Option 2 
of -$23.0 million. Compared to $841.3 million in baseline, the 
incremental cost in any given year to the private sector ranges from -
$444.5 million under Option 4 to -$327.5 million under Option 1, with 
Option 2 having an incremental cost of -$405 million. From these 
incremental cost values, the EPA determined that none of the regulatory 
options would constitute a federal mandate that may result in 
expenditures of $160 million (in 2018 dollars) or more for state, 
local, and tribal governments in the aggregate, or the private sector 
in any one year. Chapter 9 of the RIA report provides details of these 
analyses.
    This action is also not subject to the requirements of UMRA section 
203 because it contains no regulatory requirements that might 
significantly or uniquely affect small governments. To assess whether 
the regulatory options presented in this proposal would affect small 
governments in a way that is disproportionately burdensome in 
comparison to the effect on large governments, the EPA compared total 
incremental costs and incremental costs per facility for small 
governments and large governments. The EPA also compared the changes in 
per facility costs incurred for small-government-owned facilities with 
those incurred by non-government-owned facilities. The Agency evaluated 
both average and maximum annualized incremental costs per facility. 
These analyses, which are detailed in Chapter 9 of the RIA, find that 
small governments would not be significantly or uniquely affected by 
the regulatory options presented in this proposal.

F. Executive Order 13132: Federalism

    Under Executive Order (E.O.) 13132, the EPA may not issue an action 
that has federalism implications, that imposes substantial direct 
compliance costs, and that is not required by statute, unless the 
federal government provides the funds necessary to pay the direct 
compliance costs incurred by state and local governments or the EPA 
consults with state and local officials early in development of the 
action.
    The EPA anticipates that none of the regulatory options presented 
in this proposed rule would impose incremental administrative burden on 
states due to issuing, reviewing, and overseeing compliance with 
discharge requirements. Nevertheless, the EPA solicits comment on 
examples and data that demonstrate net impacts compared to the 2015 
rule baseline which would allow the Agency to evaluate these impacts 
for the final rule.
    As detailed in Chapter 9 of the RIA in the docket for this action, 
the EPA has identified 160 steam electric facilities owned by state or 
local governments, of which 16 facilities are estimated to incur costs 
to comply with the BA transport water and FGD limitations in the 2015 
rule. However, all four regulatory options presented in this proposal 
provide cost savings as compared to the baseline. The difference in the 
maximum costs of the options as compared to the baseline ranges from -
$6 million under Option 4 to -$23.5 million under Option 2. Based on 
this information, the EPA proposes to conclude that this action would 
not impose substantial direct compliance costs on state or local 
governments.

G. Executive Order 13175: Consultation and Coordination With Indian 
Tribal Governments

    This action does not have tribal implications, as specified in E.O. 
13175 (65 FR 67249, November 9, 2000). It will not have substantial 
direct effects on tribal governments, on the relationship between the 
federal government and the

[[Page 64670]]

Indian tribes, or on the distribution of power and responsibilities 
between the federal government and Indian tribes, as specified in E.O. 
13175.
    The EPA assessed potential tribal implications for the regulatory 
options presented in this proposed rule arising from three main 
changes: (1) Direct compliance costs incurred by facilities; (2) 
impacts on drinking water systems downstream from steam electric 
facilities; and (3) administrative burden on governments that implement 
the NPDES program.
    Regarding direct compliance costs, the EPA's analyses show that no 
steam electric facilities with BA transport water or FGD discharges are 
owned by tribal governments. Regarding impacts on drinking water 
systems, the EPA identified 15 public water systems operated by tribal 
governments that may be affected by bromide discharges from steam 
electric facilities. These systems serve a total of 18,917 people. The 
EPA estimated changes in bladder cancer risk and the resulting health 
benefits for the four regulatory options in comparison to the baseline. 
This analysis, which is detailed in Chapter 4 of the BCA, finds very 
small changes in exposure between the baseline and regulatory options, 
amounting to very small changes in risk for this population. Finally, 
regarding administrative burden, no tribal governments are currently 
authorized pursuant to section 402(b) of the CWA to implement the NPDES 
program. Based on this information, the EPA concluded that none of the 
regulatory options presented in the proposed rule would have 
substantial direct effects on tribal governments.

H. Executive Order 13045: Protection of Children From Environmental 
Health Risks and Safety Risks

    This action is not subject to E.O. 13045 (62 FR 19885, April 23, 
1997) because the EPA does not expect that the environmental health 
risks or safety risks associated with steam electric facility 
discharges addressed by this action present a disproportionate risk to 
children. This action's health risk assessments are in Chapters 4 and 5 
of the BCA and are summarized below.
    The EPA identified several ways in which the regulatory options 
presented in this proposal could affect children, including by 
potentially increasing health risks from changes in exposure to 
pollutants present in steam electric facility FGD wastewater and BA 
transport water discharges, or through impacts of the discharges on the 
quality of source water used by public water systems. This increase 
arises from less stringent pollutant limitations or later deadlines for 
meeting effluent limitations under certain regulatory options presented 
in this proposal as compared to the baseline. In particular, the EPA 
quantified the changes in IQ losses from lead exposure among pre-school 
children and from mercury exposure in utero resulting from maternal 
fish consumption under the four regulatory options, as compared to the 
baseline. The EPA also estimated changes in the number of children with 
very high blood lead concentrations. Finally, the EPA estimated changes 
in the lifetime risk of developing bladder cancer due to exposure to 
trihalomethanes in drinking water. The EPA did not estimate children-
specific risk because these adverse health effects normally follow 
long-term exposure. These analyses show that all of the regulatory 
options presented in this proposal would have a small, and not 
disproportionate, impact on children.

I. Executive Order 13211: Actions That Significantly Affect Energy 
Supply, Distribution, or Use

    This action is not a ``significant energy action,'' as defined by 
E.O. 13211 (66 FR 28355, May 22, 2001) because it is not likely to have 
a significant adverse effect on the supply, distribution, or use of 
energy.
    The Agency analyzed the potential energy effects of the regulatory 
options presented in this proposal relative to the baseline and found 
minimal or no impacts on electricity generation, generating capacity, 
cost of energy production, or dependence on a foreign supply of energy. 
Specifically, the Agency's analysis found that none of the regulatory 
options would reduce electricity production by more than 1 billion 
kilowatt hours per year or by 500 megawatts of installed capacity under 
either of the options analyzed, nor would the option increase U.S. 
dependence on foreign supplies of energy. For more detail on the 
potential energy effects of the regulatory options in this proposal, 
see Section 10.7 in the RIA, available in the docket.

J. National Technology Transfer and Advancement Act

    This proposed rulemaking does not involve technical standards.

K. Executive Order 12898: Federal Actions To Address Environmental 
Justice in Minority Populations and Low-Income Populations

    The EPA conducted the analysis in three ways. First, the EPA 
summarized the demographic characteristics of individuals living in 
proximity to steam electric facilities with BA transport water or FGD 
discharges and thus are likely to be affected by the facility 
discharges and changes in air emissions resulting from the regulatory 
options presented in this proposal. This first analysis focuses on the 
spatial distribution of minority and low-income groups to determine 
whether these groups are more or less represented in the populations 
that are expected to be affected by the regulatory options, based on 
their proximity to steam electric facilities. The results show that, 
when compared to state averages, all affected communities are poorer 
and a large majority of affected communities have more minority 
residents than average.
    Second, the EPA summarized the demographic characteristics of 
individuals served by public water systems (PWS) downstream from steam 
electric facilities and potentially affected by bromide discharges. The 
results show that the majority of county populations potentially 
affected by changes in drinking water quality as a result of steam 
electric facility discharges are poorer and have more minority 
residents than the state average.
    Finally, the EPA conducted analyses of populations exposed to steam 
electric power facility FGD wastewater and BA transport water 
discharges through consumption of recreationally caught fish by 
estimating exposure and health effects by demographic cohort. Where 
possible, the EPA used analytic assumptions specific to the demographic 
cohorts--e.g., fish consumption rates specific to different racial 
groups. Recreational anglers and members of their households, including 
children, are expected to experience forgone benefits from an increase 
in pollutant concentrations in fish tissue under all of the regulatory 
options. EPA estimated forgone benefits to children (i.e., IQ 
decrements) from increased mercury exposure in the populations that 
live below the poverty line and/or minority populations.
    The results show that the regulatory options would result in 
forgone benefits to these populations and that these changes may 
disproportionately affect communities in cases where the regulatory 
options increase pollutant exposure compared to the baseline. Overall 
however, the EPA's analysis, which is detailed in Chapter 14 of the 
BCA, finds very small changes in exposure between the baseline and 
regulatory options, amounting to very small changes in risk for this 
population. The EPA solicits comment on the assumptions and 
uncertainties included in this analysis.

[[Page 64671]]

L. Congressional Review Act (CRA)

    This action is subject to the CRA, and the EPA will submit a rule 
report to each House of the Congress and to the Comptroller General of 
the United States. This action is a ``major rule'' as defined by 5 
U.S.C. 804(2).

Appendix A to the Preamble: Definitions, Acronyms, and Abbreviations 
Used in This Preamble

    The following acronyms and abbreviations are used in this 
preamble.
    Administrator. The Administrator of the U.S. Environmental 
Protection Agency.
    Agency. U.S. Environmental Protection Agency.
    BAT. Best available technology economically achievable, as 
defined by CWA sections 301(b)(2)(A) and 304(b)(2)(B).
    Bioaccumulation. General term describing a process by which 
chemicals are taken up by an organism either directly from exposure 
to a contaminated medium or by consumption of food containing the 
chemical, resulting in a net accumulation of the chemical by an 
organism due to uptake from all routes of exposure.
    BMP. Best management practice.
    BA. The ash, including boiler slag, which settles in the furnace 
or is dislodged from furnace walls. Economizer ash is included when 
it is collected with BA.
    BPT. The best practicable control technology currently available 
as defined by sections 301(b)(1) and 304(b)(1) of the CWA.
    CBI. Confidential Business Information.
    CCR. Coal Combustion Residuals.
    Clean Water Act (CWA). The Federal Water Pollution Control Act 
Amendments of 1972 (33 U.S.C. 1251 et seq.), as amended, e.g., by 
the Clean Water Act of 1977 (Pub. L. 95-217), and the Water Quality 
Act of 1987 (Pub. L. 100-4).
    Combustion residuals. Solid wastes associated with combustion-
related power facility processes, including fly and BA from coal-, 
petroleum coke-, or oil-fired units; FGD solids; FGMC wastes; and 
other wastewater treatment solids associated with combustion 
wastewater. In addition to the residuals that are associated with 
coal combustion, this also includes residuals associated with the 
combustion of other fossil fuels.
    Direct discharge. (a) Any addition of any ``pollutant'' or 
combination of pollutants to ``waters of the United States'' from 
any ``point source,'' or (b) any addition of any pollutant or 
combination of pollutant to waters of the ``contiguous zone'' or the 
ocean from any point source other than a vessel or other floating 
craft which is being used as a means of transportation. This 
definition includes additions of pollutants into waters of the 
United States from: Surface runoff which is collected or channeled 
by man; discharges though pipes, sewers, or other conveyances owned 
by a State, municipality, or other person which do not lead to a 
treatment works; and discharges through pipes, sewers, or other 
conveyances, leading into privately owned treatment works. This term 
does not include an addition of pollutants by any ``indirect 
discharger.''
    Direct discharger. A facility that discharges treated or 
untreated wastewaters into waters of the U.S.
    DOE. Department of Energy.
    Dry BA handling system. A system that does not use water as the 
transport medium to convey BA away from the boiler. It includes 
systems that collect and convey the ash without any use of water, as 
well as systems in which BA is quenched in a water bath and then 
mechanically or pneumatically conveyed away from the boiler. Dry BA 
handling systems do not include wet sluicing systems (such as remote 
MDS or complete recycle systems).
    Effluent limitation. Under CWA section 502(11), any restriction, 
including schedules of compliance, established by a state or the 
Administrator on quantities, rates, and concentrations of chemical, 
physical, biological, and other constituents which are discharged 
from point sources into navigable waters, the waters of the 
contiguous zone, or the ocean, including schedules of compliance.
    EIA. Energy Information Administration.
    ELGs. Effluent limitations guidelines and standards.
    E.O. Executive Order.
    EPA. U.S. Environmental Protection Agency.
    FA. Fly Ash
    Facility. Any NPDES ``point source'' or any other facility or 
activity (including land or appurtenances thereto) that is subject 
to regulation under the NPDES program.
    FGD. Flue Gas Desulfurization.
    FGD Wastewater. Wastewater generated specifically from the wet 
FGD scrubber system that comes into contact with the flue gas or the 
FGD solids, including, but not limited to, the blowdown or purge 
from the FGD scrubber system, overflow or underflow from the solids 
separation process, FGD solids wash water, and the filtrate from the 
solids dewatering process. Wastewater generated from cleaning the 
FGD scrubber, cleaning FGD solids separation equipment, cleaning FGD 
solids dewatering equipment, or that is collected in floor drains in 
the FGD process area is not considered FGD wastewater.
    Fly Ash. The ash that is carried out of the furnace by a gas 
stream and collected by a capture device such as a mechanical 
precipitator, electrostatic precipitator, and/or fabric filter. 
Economizer ash is included in this definition when it is collected 
with fly ash. Ash is not included in this definition when it is 
collected in wet scrubber air pollution control systems whose 
primary purpose is particulate removal.
    Groundwater. Water that is found in the saturated part of the 
ground underneath the land surface.
    Indirect discharge. Wastewater discharged or otherwise 
introduced to a POTW.
    IPM. Integrated Planning Model.
    Landfill. A disposal facility or part of a facility where solid 
waste, sludges, or other process residuals are placed in or on any 
natural or manmade formation in the earth for disposal and which is 
not a storage pile, a land treatment facility, a surface 
impoundment, an underground injection well, a salt dome or salt bed 
formation, an underground mine, a cave, or a corrective action 
management unit.
    MDS. Mechanical drag system.
    Mechanical drag system. BA handling system that collects BA from 
the bottom of the boiler in a water-filled trough. The water bath in 
the trough quenches the hot BA as it falls from the boiler and seals 
the boiler gases. A drag chain operates in a continuous loop to drag 
BA from the water trough up an incline, which dewaters the BA by 
gravity, draining the water back to the trough as the BA moves 
upward. The dewatered BA is often conveyed to a nearby collection 
area, such as a small bunker outside the boiler building, from which 
it is loaded onto trucks and either sold or transported to a 
landfill. The MDS is considered a dry BA handling system because the 
ash transport mechanism is mechanical removal by the drag chain, not 
the water.
    Mortality. Death rate or proportion of deaths in a population.
    NAICS. North American Industry Classification System.
    NPDES. National Pollutant Discharge Elimination System.
    ORCR. Office of Resource Conservation and Recovery.
    Paste. A substance containing solids in a fluid which behaves as 
a solid until a force is applied which causes it to behave like a 
fluid.
    Paste Landfill. A landfill which receives any paste designed to 
set into a solid after the passage of a reasonable amount of time.
    Point source. Any discernable, confined, and discrete 
conveyance, including but not limited to, any pipe, ditch, channel, 
tunnel, conduit, well, discrete fissure, container, rolling stock, 
concentrated animal feeding operation, or vessel or other floating 
craft from which pollutants are or may be discharged. The term does 
not include agricultural stormwater discharges or return flows from 
irrigated agriculture. See CWA section 502(14), 33 U.S.C. 1362(14); 
40 CFR 122.2.
    POTW. Publicly owned treatment works. See CWA section 212, 33 
U.S.C. 1292; 40 CFR 122.2, 403.3.
    PSES. Pretreatment Standards for Existing Sources.
    Publicly Owned Treatment Works. Any device or system, owned by a 
state or municipality, used in the treatment (including recycling 
and reclamation) of municipal sewage or industrial wastes of a 
liquid nature that is owned by a state or municipality. This 
includes sewers, pipes, or other conveyances only if they convey 
wastewater to a POTW providing treatment. CWA section 212, 33 U.S.C. 
1292; 40 CFR 122.2, 403.3.
    RCRA. The Resource Conservation and Recovery Act of 1976, 42 
U.S.C. 6901 et seq.
    Remote MDS. BA handling system that collects BA at the bottom of 
the boiler, then uses transport water to sluice the ash to a remote 
MDS that dewaters BA using a similar configuration as the MDS. The 
remote MDS is considered a wet BA handling system because the ash 
transport mechanism is water.
    RFA. Regulatory Flexibility Act.
    SBA. Small Business Administration.

[[Page 64672]]

    Sediment. Particulate matter lying below water.
    Surface water. All waters of the United States, including 
rivers, streams, lakes, reservoirs, and seas.
    Toxic pollutants. As identified under the CWA, 65 pollutants and 
classes of pollutants, of which 126 specific substances have been 
designated priority toxic pollutants. see appendix A to 40 CFR part 
423.
    Transport water. Wastewater that is used to convey FA, BA, or 
economizer ash from the ash collection or storage equipment, or 
boiler, and has direct contact with the ash. Transport water does 
not include low volume, short duration discharges of wastewater from 
minor leaks (e.g., leaks from valve packing, pipe flanges, or 
piping) or minor maintenance events (e.g., replacement of valves or 
pipe sections).
    UMRA. Unfunded Mandates Reform Act.
    Wet BA handling system. A system in which BA is conveyed away 
from the boiler using water as a transport medium. Wet BA systems 
typically send the ash slurry to dewatering bins or a surface 
impoundment. Wet BA handling systems include systems that operate in 
conjunction with a traditional wet sluicing system to recycle all BA 
transport water (remote MDS or complete recycle system).
    Wet FGD system. Wet FGD systems capture sulfur dioxide from the 
flue gas using a sorbent that has mixed with water to form a wet 
slurry, and that generates a water stream that exits the FGD 
scrubber absorber.

List of Subjects in 40 CFR Part 423

    Environmental protection, Electric power generation, Power 
facilities, Waste treatment and disposal, Water pollution control.

    Dated: November 4, 2019.
Andrew R. Wheeler,
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: Secs. 101; 301; 304(b), (c), (e), and (g); 306; 307; 
308 and 501, Clean Water Act (Federal Water Pollution Control Act 
Amendments of 1972, as amended; 33 U.S.C. 1251; 1311; 1314(b), (c), 
(e), and (g); 1316; 1317; 1318 and 1361).

0
2. Amend Sec.  423.11 by revising paragraphs (n), (p), and (t) and 
adding paragraphs (u), (v), (w), (x), (y), (z), (aa), (bb), (cc), and 
(dd).

Sec.  423.11  Specialized definitions.

* * * * *
    (n) The term flue gas desulfurization (FGD) wastewater means any 
wastewater generated specifically from the wet flue gas desulfurization 
scrubber system that comes into contact with the flue gas or the FGD 
solids, including but not limited to, the blowdown from the FGD 
scrubber system, overflow or underflow from the solids separation 
process, FGD solids wash water, and the filtrate from the solids 
dewatering process. Wastewater generated from cleaning the FGD 
scrubber, cleaning FGD solids separation equipment, cleaning FGD solids 
dewatering equipment, cleaning FGD paste transportation piping, or that 
is collected in floor drains in the FGD process area is not considered 
FGD wastewater.
* * * * *
    (p) The term transport water means any wastewater that is used to 
convey fly ash, bottom ash, or economizer ash from the ash collection 
or storage equipment, or boiler, and has direct contact with the ash. 
Transport water does not include low volume, short duration discharges 
of wastewater from minor leaks (e.g., leaks from valve packing, pipe 
flanges, or piping), minor maintenance events (e.g., replacement of 
valves or pipe sections), cleaning FGD paste transportation piping, 
wastewater present in equipment when a facility is retired from 
service, or maintenance purge water.
* * * * *
    (t) The phrase ``as soon as possible'' means November 1, 2018 
(except for purposes of Sec.  423.13(g)(1)(i) and (k)(1)(i), and Sec.  
423.16(e) and (g), in which case it means November 1, 2020), unless the 
permitting authority establishes a later date, after receiving site-
specific information from the discharger, which reflects a 
consideration of the following factors:
    (1) Time to expeditiously plan (including to raise capital), 
design, procure, and install equipment to comply with the requirements 
of this part.
    (2) Changes being made or planned at the plant in response to:
    (i) New source performance standards for greenhouse gases from new 
fossil fuel-fired electric generating units, under sections 111, 301, 
302, and 307(d)(1)(C) of the Clean Air Act, as amended, 42 U.S.C. 7411, 
7601, 7602, 7607(d)(1)(C);
    (ii) Emission guidelines for greenhouse gases from existing fossil 
fuel-fired electric generating units, under sections 111, 301, 302, and 
307(d) of the Clean Air Act, as amended, 42 U.S.C. 7411, 7601, 7602, 
7607(d); or
    (iii) Regulations that address the disposal of coal combustion 
residuals as solid waste, under sections 1006(b), 1008(a), 2002(a), 
3001, 4004, and 4005(a) of the Solid Waste Disposal Act of 1970, as 
amended by the Resource Conservation and Recovery Act of 1976, as 
amended by the Hazardous and Solid Waste Amendments of 1984, 42 U.S.C. 
6906(b), 6907(a), 6912(a), 6944, and 6945(a).
    (3) For FGD wastewater requirements only, an initial commissioning 
period for the treatment system to optimize the installed equipment.
    (4) Other factors as appropriate.
    (u) The term ``FGD paste'' means any combination of FGD wastewater 
treated with fly ash and/or lime prior to being landfilled, that is 
engineered to form a solid through pozzolanic reactions.
    (v) The term ``FGD paste transportation piping'' means any pipe, 
valve, or related item used for transporting FGD paste from its point 
of generation to a landfill.
    (w) The term ``retired from service'' means the owner or operator 
of a boiler no longer has, or is no longer required to have, the 
necessary permission through a permit, license, or other legally 
applicable form of permission to conduct electricity generation 
activities under Federal, state, or local law, irrespective of whether 
the owner and operator is subject to this part.
    (x) The term ``high FGD flow'' means the maximum daily volume of 
FGD wastewater that could be discharged by a facility is above 4 
million gallons per day after accounting for that facility's ability to 
recycle the wastewater to the maximum limits for the FGD system 
materials of construction.
    (y) The term ``net generation'' means the amount of gross 
electrical generation less the electrical energy consumed at the 
generating station(s) for station service or auxiliaries as calculated 
in paragraph 423.19(e) of this subpart.
    (z) The term ``low utilization boiler'' means any boiler for which 
the facility owner certifies, and annually recertifies, under 423.19(e) 
that the two-year average annual net generation is below 876,000 MWh 
per year.
    (aa) The term ``primary active wetted bottom ash system volume'' 
means the maximum volumetric capacity of bottom ash transport water in 
all piping (including recirculation piping) and primary tanks of a wet 
bottom ash system, excluding the volumes of installed spares, 
redundancies, maintenance tanks, other secondary bottom ash system 
equipment, and non-bottom ash transport systems that may direct process 
water to the bottom ash system as certified to in paragraph 423.19(c).
    (bb) The term ``tank'' means a stationary device, designed to 
contain

[[Page 64673]]

an accumulation of wastewater which is constructed primarily of non-
earthen materials (e.g., wood, concrete, steel, plastic) which provide 
structural support.
    (cc) The term ``maintenance purge water'' means any water being 
discharged subject to paragraphs Sec.  423.13(k)(2)(i) or Sec.  
423.16(g)(2)(i).
    (dd) The term ``30-day rolling average'' means the series of 
averages using the measured values of the preceding 30 days for each 
average in the series.
0
3. Amend Sec.  423.12 by revising paragraph (b)(11).

Sec.  423.12  Effluent limitations guidelines representing the degree 
of effluent reduction attainable by the application of the best 
practicable control technology currently available (BPT).

* * * * *
    (b) * * *
    (11) The quantity of pollutants discharged in FGD wastewater, flue 
gas mercury control wastewater, combustion residual leachate, 
gasification wastewater, or bottom ash maintenance purge water shall 
not exceed the quantity determined by multiplying the flow of the 
applicable wastewater times the concentration listed in table 1:

                                          Table 1 to Paragraph (b)(11)
----------------------------------------------------------------------------------------------------------------
                                                                           BPT effluent limitations
                                                             ---------------------------------------------------
               Pollutant or pollutant property                                           Average of daily values
                                                                Maximum for any 1 day    for 30 consecutive days
                                                                       (mg/l)            shall not exceed (mg/l)
----------------------------------------------------------------------------------------------------------------
TSS.........................................................                     100.0                      30.0
Oil and grease..............................................                      20.0                      15.0
----------------------------------------------------------------------------------------------------------------

* * * * *
0
4. Amend Sec.  423.13 by:
0
a. Revising paragraph (g)(1)(i);
0
b. Redesignating paragraph (g)(2) as paragraph (g)(2)(i) and revising 
the newly redesignated paragraph (g)(2)(i);
0
c. Adding paragraphs (g)(2)(ii) and (g)(2)(iii);
0
d. Revising paragraphs (g)(3)(i) and paragraph (k)(1)(i);
0
e. Redesignating paragraph (k)(2) as (k)(2)(ii) and revising newly 
redesignated (k)(2)(ii); and
0
f. Adding paragraphs (k)(2)(i), (k)(2)(iii), and (k)(3).
    The additions and revisions to 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).

* * * * *
    (g)(1)(i) FGD wastewater. Except for those discharges to which 
paragraph (g)(2) or (g)(3) of this section applies, the quantity of 
pollutants in FGD wastewater shall not exceed the quantity determined 
by multiplying the flow of FGD wastewater times the concentration 
listed in the table following this paragraph (g)(1)(i). Dischargers 
must meet the effluent limitations for FGD wastewater in this paragraph 
by a date determined by the permitting authority that is as soon as 
possible beginning November 1, 2020, but no later than December 31, 
2025. These effluent limitations apply to the discharge of FGD 
wastewater generated on and after the date determined by the permitting 
authority for meeting the effluent limitations, as specified in this 
paragraph.

                                         Table 1 to Paragraph (g)(1)(i)
----------------------------------------------------------------------------------------------------------------
                                                                           BAT effluent limitations
                                                             ---------------------------------------------------
               Pollutant or pollutant property                                           Average of daily values
                                                                Maximum for any 1 day    for 30 consecutive days
                                                                                            shall not exceed
----------------------------------------------------------------------------------------------------------------
Arsenic, total (ug/L).......................................                        18                         9
Mercury, total (ng/L).......................................                        85                        31
Selenium, total (ug/L)......................................                        76                        31
Nitrate/nitrite as N (mg/L).................................                       4.6                       3.2
----------------------------------------------------------------------------------------------------------------

* * * * *
    (2)(i) For any electric generating unit with a total nameplate 
capacity of less than or equal to 50 megawatts, that is an oil-fired 
unit, or for which the owner has certified pursuant to 423.19(f) will 
be retired from service by December 31, 2028, the quantity of 
pollutants discharged in FGD wastewater shall not exceed the quantity 
determined by multiplying the flow of FGD wastewater times the 
concentration listed for TSS in Sec.  423.12(b)(11).
    (ii) For FGD wastewater discharges from a high FGD flow facility, 
the quantity of pollutants in FGD wastewater shall not exceed the 
quantity determined by multiplying the flow of FGD wastewater times the 
concentration listed in the table following this paragraph (g)(2)(ii). 
Dischargers must meet the effluent limitations for FGD wastewater in 
this paragraph by a date determined by the permitting authority that is 
as soon as possible beginning November 1, 2020, but no later than 
December 31, 2023. These effluent limitations apply to the discharge of 
FGD wastewater generated on and after the date determined by the 
permitting authority for meeting the effluent limitations, as specified 
in this paragraph (g)(2)(ii).

[[Page 64674]]

                                         Table 1 to Paragraph (g)(2)(ii)
----------------------------------------------------------------------------------------------------------------
                                                                           BAT effluent limitations
                                                             ---------------------------------------------------
               Pollutant or pollutant property                                           Average of daily values
                                                                Maximum for any 1 day    for 30 consecutive days
                                                                                            shall not exceed
----------------------------------------------------------------------------------------------------------------
Arsenic, total (ug/L).......................................                        11                         8
Mercury, total (ng/L).......................................                       788                       356
----------------------------------------------------------------------------------------------------------------

    (iii)(A) For FGD wastewater discharges from a low utilization 
boiler, the quantity of pollutants in FGD wastewater shall not exceed 
the quantity determined by multiplying the flow of FGD wastewater times 
the concentration listed in the Table 1 to paragraph (g)(2)(ii). 
Dischargers must meet the effluent limitations for FGD wastewater in 
this paragraph by a date determined by the permitting authority that is 
as soon as possible beginning November 1, 2020, but no later than 
December 31, 2023. These effluent limitations apply to the discharge of 
FGD wastewater generated on and after the date determined by the 
permitting authority for meeting the effluent limitations, as specified 
in this paragraph (g)(2)(iii)(A).
    (B) If any low utilization boiler fails to timely recertify that 
the two year average net generation of such a boiler is below 876,000 
MWh per year as specified in Sec.  423.19(e), regardless of the reason, 
within two years from the date such a recertification was required, the 
quantity of pollutants in FGD wastewater shall not exceed the quantity 
determined by multiplying the flow of FGD wastewater times the 
concentration listed in the Table 1 to paragraph (g)(1)(i).
    (3)(i) For dischargers who voluntarily choose to meet the effluent 
limitations for FGD wastewater in this paragraph, the quantity of 
pollutants in FGD wastewater shall not exceed the quantity determined 
by multiplying the flow of FGD wastewater times the concentration 
listed in the table following this paragraph (g)(3)(i). Dischargers who 
choose to meet the effluent limitations for FGD wastewater in this 
paragraph must meet such limitations by December 31, 2028. These 
effluent limitations apply to the discharge of FGD wastewater generated 
on and after December 31, 2028.

                                         Table 1 to Paragraph (g)(3)(i)
----------------------------------------------------------------------------------------------------------------
                                                                            BAT Effluent limitations
                                                               -------------------------------------------------
                Pollutant or pollutant property                                          Average of daily values
                                                                 Maximum for any 1 day   for 30 consecutive days
                                                                                             shall not exceed
----------------------------------------------------------------------------------------------------------------
Arsenic, total (ug/L).........................................                        5  .......................
Mercury, total (ng/L).........................................                       21                        9
Selenium, total (ug/L)........................................                       21                       11
Nitrate/Nitrite (mg/L)........................................                      1.1                      0.6
Bromide (mg/L)................................................                      0.6                      0.3
TDS (mg/L)....................................................                      351                      156
----------------------------------------------------------------------------------------------------------------

* * * * *
    (k)(1)(i) Bottom ash transport water. Except for those discharges 
to which paragraph (k)(2) of this section applies, or when the bottom 
ash transport water is used in the FGD scrubber, there shall be no 
discharge of pollutants in bottom ash transport water. Dischargers must 
meet the discharge limitation in this paragraph by a date determined by 
the permitting authority that is as soon as possible beginning November 
1, 2020, but no later than December 31, 2023. This limitation applies 
to the discharge of bottom ash transport water generated on and after 
the date determined by the permitting authority for meeting the 
discharge limitation, as specified in this paragraph (k)(1)(i). Except 
for those discharges to which paragraph (k)(2) of this section applies, 
whenever bottom ash transport water is used in any other plant process 
or is sent to a treatment system at the plant (except when it is used 
in the FGD scrubber), the resulting effluent must comply with the 
discharge limitation in this paragraph. When the bottom ash transport 
water is used in the FGD scrubber, the quantity of pollutants in bottom 
ash transport water shall not exceed the quantity determined by 
multiplying the flow of bottom ash transport water times the 
concentration listed in Table 1 to paragraph (g)(1)(i) of this section.
* * * * *
    (2)(i)(A) The discharge of pollutants in bottom ash transport water 
from a properly installed, operated, and maintained bottom ash system 
is authorized under the following conditions:
    (1) To maintain system water balance when precipitation-related 
inflows within any 24-hour period resulting from a 25-year, 24-hour 
storm event, or multiple consecutive events cannot be managed by 
installed spares, redundancies, maintenance tanks, and other secondary 
bottom ash system equipment; or
    (2) To maintain water balance when regular inflows from 
wastestreams other than bottom ash transport water exceed the ability 
of the bottom ash system to accept recycled water and segregating these 
other wastestreams is not feasible; or
    (3) To conduct maintenance not otherwise exempted from the 
definition of transport water in Sec.  423.11(p) when water volumes 
cannot be managed by installed spares, redundancies, maintenance tanks, 
and other secondary bottom ash system equipment; or
    (4) To maintain system water chemistry where installed equipment at 
the facility is unable to manage pH, corrosive compounds, and fine 
particulates to below levels which impact system operations.
    (B) The total volume necessary to be discharged for the above 
activities shall be reduced or eliminated to the extent

[[Page 64675]]

achievable using control measures (including best management practices) 
that are technologically available and economically achievable in light 
of best industry practice, and in no instance shall it exceed a 30-day 
rolling average of ten percent of the primary active wetted bottom ash 
system volume. Discharges shall be measured by computing daily 
discharges by totaling daily flow discharges.
    (ii) For any electric generating unit with a total nameplate 
generating capacity of less than or equal to 50 megawatts, that is an 
oil-fired unit, or for which the owner has certified pursuant to 
423.19(f) will be retired from service by December 31, 2028, the 
quantity of pollutants discharged in bottom ash transport water shall 
not exceed the quantity determined by multiplying the flow of the 
applicable wastewater times the concentration for TSS listed in Sec.  
423.12(b)(4).
    (iii)(A) For bottom ash transport water generated by a low 
utilization boiler, the quantity of pollutants discharged in bottom ash 
transport water shall not exceed the quantity determined by multiplying 
the flow of the applicable wastewater times the concentration for TSS 
listed in Sec.  423.12(b)(4),and shall incorporate the elements of a 
best management practices plan as described in (k)(3) of this section.
    (B) If any low utilization boiler fails to timely recertify that 
the two year average net generation of such a boiler is below 876,000 
MWh per year as specified in 423.19(e), regardless of the reason, 
within two years from the date such a recertification was required, the 
quantity of pollutants discharged in bottom ash transport water shall 
be governed by paragraphs (k)(1) and (k)(2)(i) of this section.
    (3) Where required in paragraph (k)(2)(iii) of this section, the 
discharger shall prepare, implement, review, and update a best 
management practices plan for the recycle of bottom ash transport 
water, and must include:
    (i) Identification of the low utilization coal-fired generating 
units that contribute bottom ash to the bottom ash transport system.
    (ii) A description of the existing bottom ash handling system and a 
list of system components (e.g., remote mechanical drag system (rMDS), 
tanks, impoundments, chemical addition). Where multiple generating 
units share a bottom ash transport system, the plan shall specify which 
components are associated with low utilization generating units.
    (iii) A detailed water balance, based on measurements, or estimates 
where measurements are not feasible, specifying the volume and 
frequency of water additions and removals from the bottom ash transport 
system, including:
    (A) Water removed from the BA transport system:
    (1) To the discharge outfall.
    (2) To the FGD scrubber system.
    (3) Through evaporation.
    (4) Entrained with any removed ash.
    (5) Other mechanisms not specified herein.
    (B) Entering or recycled to the BA transport system:
    (1) Makeup water added to the BA transport water system.
    (2) Bottom ash transport water recycled back to the system in lieu 
of makeup water.
    (3) Other mechanisms not specified herein.
    (iv) Measures to be employed by all facilities:
    (A) Implementation of a comprehensive preventive maintenance 
program to identify, repair and replace equipment prior to failures 
that result in the release of bottom ash transport water.
    (B) Daily or more frequent inspections of the entire bottom ash 
transport water system, including valves, pipe flanges and piping, to 
identify leaks, spills and other unintended bottom ash transport water 
escaping from the system, and timely repair of such conditions.
    (C) Documentation of preventive and corrective maintenance 
performed.
    (v) Evaluation of options and feasibility, accounting for the 
associated costs, for eliminating or minimizing discharges of bottom 
ash transport water, including:
    (A) Segregating bottom ash transport water from other process 
water.
    (B) Minimizing the introduction of stormwater by diverting (e.g., 
curbing, using covers) storm water to a segregated collection system.
    (C) Recycling bottom ash transport water back to the bottom ash 
transport water system.
    (D) Recycling bottom ash transport water for use in the FGD 
scrubber.
    (E) Optimizing existing equipment (e.g., pumps, pipes, tanks) and 
installing new equipment where practicable to achieve the maximum 
amount of recycle.
    (F) Utilizing ``in-line'' treatment of transport water (e.g., pH 
control, fines removal) where needed to facilitate recycle.
    (vi) Description of the bottom ash recycle system, including all 
technologies, measures, and practices that will be used to minimize 
discharge.
    (vii) A schedule showing the sequence of implementing any changes 
necessary to achieve the minimized discharge of bottom ash transport 
water, including the following:
    (A) The anticipated initiation and completion dates of construction 
and installation associated with the technology components or process 
modifications specified in the plan.
    (B) The anticipated dates that the discharger expects the 
technologies and process modifications to be fully implemented on a 
full-scale basis, which in no case shall be later than December 31, 
2023.
    (C) The anticipated change in discharge volume and effluent quality 
associated with implementation of the plan.
    (viii) Description establishing a method for documenting and 
demonstrating to the permitting/control authority that the recycle 
system is well operated and maintained.
    (ix) The discharger shall perform weekly flow monitoring for the 
following:
    (A) Make up water to the bottom ash transport water system.
    (B) Bottom ash transport water sluice flow rate (e.g., to the 
surface impoundment(s), dewatering bins(s), tank(s), rMDS).
    (C) Bottom ash transport water discharge to surface water or POTW.
    (D) Bottom ash transport water recycle back to the bottom ash 
system or FGD scrubber.
* * * * *
0
5. Amend Sec.  423.16 by:
0
a. Revising paragraph (e)(1);
0
b. Adding paragraph (e)(2);
0
c. Revising paragraph (g)(1); and
0
d. Adding paragraph (g)(2).
    The additions and revisions to read as follows

Sec.  423.16  Pretreatment standards for existing sources (PSES).

* * * * *
    (e)(1) FGD wastewater. Except as provided for in paragraph (e)(2) 
of this section, for any electric generating unit with a total 
nameplate generating capacity of more than 50 megawatts, that is not an 
oil-fired unit, and that the owner has not certified pursuant to Sec.  
423.19(f) will be retired from service by December 31, 2028, the 
quantity of pollutants in FGD wastewater shall not exceed the quantity 
determined by multiplying the flow of FGD wastewater times the 
concentration listed in the table following this paragraph (e). 
Dischargers must meet the standards in this paragraph by [DATE 3 YEARS 
AFTER DATE OF FINAL RULE] except as provided for in paragraph (e)(2) of 
this section. These standards apply to the discharge of FGD wastewater 
generated on and after [DATE 3 YEARS AFTER DATE OF FINAL RULE].

[[Page 64676]]

                                           Table 1 to Paragraph (e)(1)
----------------------------------------------------------------------------------------------------------------
                                                                                      PSES
                                                               -------------------------------------------------
                Pollutant or pollutant property                                          Average of daily values
                                                                 Maximum for any 1 day   for 30 consecutive days
                                                                                             shall not exceed
----------------------------------------------------------------------------------------------------------------
Arsenic, total (ug/L).........................................                       18                        9
Mercury, total (ng/L).........................................                       85                       31
Selenium, total (ug/L)........................................                       76                       31
Nitrate/nitrite as N (mg/L)...................................                      4.6                      3.2
----------------------------------------------------------------------------------------------------------------

    (2)(i) For FGD wastewater discharges from a low utilization boiler, 
the quantity of pollutants in FGD wastewater shall not exceed the 
quantity determined by multiplying the flow of FGD wastewater times the 
concentration listed in the table following this paragraph (e)(2). 
Dischargers must meet the standards in this paragraph by [DATE 3 YEARS 
AFTER DATE OF FINAL RULE].
    (ii) If any low utilization boiler fails to timely recertify that 
the two year average net generation of such a boiler is below 876,000 
MWh per year as specified in Sec.  423.19(e), regardless of the reason, 
within two years from the date such a recertification was required, the 
quantity of pollutants in FGD wastewater shall not exceed the quantity 
determined by multiplying the flow of FGD wastewater times the 
concentration listed in Table 1 to paragraph (e)(1).

                                         Table 1 to Paragraph (e)(2)(ii)
----------------------------------------------------------------------------------------------------------------
                                                                                      PSES
                                                               -------------------------------------------------
                Pollutant or pollutant property                                          Average of daily values
                                                                 Maximum for any 1 day   for 30 consecutive days
                                                                                             shall not exceed
----------------------------------------------------------------------------------------------------------------
Arsenic, total (ug/L).........................................                       11                        8
Mercury, total (ng/L).........................................                      788                      356
----------------------------------------------------------------------------------------------------------------

* * * * *
    (g)(1) Except for those discharges to which paragraph (g)(2) of 
this section applies, or when the bottom ash transport water is used in 
the FGD scrubber, for any electric generating unit with a total 
nameplate generating capacity of more than 50 megawatts, that is not an 
oil-fired unit, that is not a low utilization boiler, and that the 
owner has not certified pursuant to Sec.  423.19(f) will be retired 
from service by December 31, 2028, there shall be no discharge of 
pollutants in bottom ash transport water. This standard applies to the 
discharge of bottom ash transport water generated on and after [DATE 3 
YEARS AFTER DATE OF FINAL RULE]. Except for those discharges to which 
paragraph (g)(2) of this section applies, whenever bottom ash transport 
water is used in any other plant process or is sent to a treatment 
system at the plant (except when it is used in the FGD scrubber), the 
resulting effluent must comply with the discharge standard in this 
paragraph. When the bottom ash transport water is used in the FGD 
scrubber, the quantity of pollutants in bottom ash transport water 
shall not exceed the quantity determined by multiplying the flow of 
bottom ash transport water times the concentration listed in Table 1 to 
paragraph (e)(1) of this section.
    (2)(i)(A) The discharge of pollutants in bottom ash transport water 
from a properly installed, operated, and maintained bottom ash system 
is authorized under the following conditions:
    (1) To maintain system water balance when precipitation-related 
inflows within any 24-hour period resulting from a 25-year, 24-hour 
storm event, or multiple consecutive events cannot be managed by 
installed spares, redundancies, maintenance tanks, and other secondary 
bottom ash system equipment; or
    (2) To maintain water balance when regular inflows from 
wastestreams other than bottom ash transport water exceed the ability 
of the bottom ash system to accept recycled water and segregating these 
other wastestreams is feasible; or
    (3) To conduct maintenance not otherwise exempted from the 
definition of transport water in Sec.  423.11(p) when water volumes 
cannot be managed by installed spares, redundancies, maintenance tanks, 
and other secondary bottom ash system equipment; or
    (4) To maintain system water chemistry where current operations at 
the facility are unable to currently manage pH, corrosive compounds, 
and fine particulates to below levels which impact system operations.
    (B) The total volume necessary to be discharged to a POTW for the 
above activities shall be reduced or eliminated to the extent 
achievable using control measures (including best management practices) 
that are technologically available and economically achievable in light 
of best industry practice, and in no instance shall it exceed a 30-day 
rolling average of ten percent of the primary active wetted bottom ash 
system volume. Discharges shall be measured by computing daily 
discharges by totaling daily flow discharges.
    (ii)(A) For bottom ash transport water generated by a low 
utilization boiler, the quantity of pollutants discharged in bottom ash 
transport water shall incorporate the elements of a best management 
practices plan as described in Sec.  423.13(k)(3).
    (B) If any low utilization boiler fails to timely recertify that 
the two year average net generation of such a boiler is below 876,000 
MWh per year as specified in Sec.  423.19(e), regardless of the reason, 
within two years from the date such a recertification was required, the 
quantity of pollutants discharged in bottom ash transport water shall 
be governed by paragraphs (g)(1) and (g)(2)(i) of this section.
0
6. Add Sec.  423.18 to read as follows.

Sec.  423.18  Permit conditions.

    All permits subject to this part shall include the following permit 
conditions:
    (a) In case of an emergency order issued by the Department of 
Energy under Section 202(c) of the Federal Power Act or a Public 
Utility Commission reliability must run agreement, a boiler shall be 
deemed to qualify as a low utilization boiler or

[[Page 64677]]

boiler that will be retired from service by December 31, 2028 if such 
qualification would have been demonstrated absent such order or 
agreement.
    (b) Any facility providing the required documentation pursuant to 
Sec.  423.19(g) may avail itself of the protections of this permit 
condition.
0
7. Add Sec.  423.19 to read as follows.

Sec.  423.19  Reporting and recordkeeping requirements.

    (a) Discharges subject to this part must comply with the following 
reporting requirements in addition to the applicable requirements in 40 
CFR 403.12(b), (d), (e), and (g).
    (b) Signature and certification. Unless otherwise provided below, 
all certifications and recertifications required in this part must be 
signed and certified pursuant to 40 CFR 122.22 for direct dischargers 
or 40 CFR 403.12(l) for indirect dischargers.
    (c) Requirements for facilities discharging bottom ash transport 
water pursuant to Sec.  423.13(k)(2)(i) or Sec.  423.16(g)(2)(i).
    (1) Initial Certification Statement. For sources seeking to 
discharge bottom ash transport water pursuant to Sec.  423.13(k)(2)(i) 
or Sec.  423.16(g)(2)(i), an initial certification shall be submitted 
to the permitting authority by the as soon as possible date determined 
under Sec.  423.11(t), or the control authority by [DATE 3 YEARS AFTER 
DATE OF FINAL RULE] in the case of an indirect discharger.
    (2) Signature and certification. The certification statement must 
be signed and certified by a professional engineer.
    (3) Contents. An initial certification shall include the following:
    (A) A statement that the professional engineer is a licensed 
professional engineer.
    (B) A statement that the professional engineer is familiar with the 
regulation requirements.
    (C) A statement that the professional engineer is familiar with the 
facility.
    (D) The primary active wetted bottom ash system volume in Sec.  
423.11(aa).
    (E) All assumptions, information, and calculations used by the 
certifying professional engineer to determine the primary active wetted 
bottom ash system volume.
    (d) Requirements for a bottom ash best management practices plan.
    (1) Initial and Annual Certification Statement. For sources 
required to develop and implement a best management practices plan 
pursuant to Sec.  423.13(k)(3), an initial certification shall be made 
to the permitting authority with a permit application, or to the 
control authority no later than [DATE 3 YEARS AFTER DATE OF FINAL RULE] 
in the case of an indirect discharger, and an annual recertification 
shall be made to the permitting authority, or control authority in the 
case of an indirect discharger, within 60 days of the anniversary of 
the original plan.
    (2) Signature and Certification. The certification statement must 
be signed and certified by a professional engineer.
    (3) Contents for Initial Certification. An initial certification 
shall include the following:
    (A) A statement that the professional engineer is a licensed 
professional engineer.
    (B) A statement that the professional engineer is familiar with the 
regulation requirements.
    (C) A statement that the professional engineer is familiar with the 
facility.
    (D) The approved best management practices plan.
    (E) A statement that the best management practices plan is being 
implemented.
    (4) Additional Contents for Annual Certification. In addition to 
the required contents of the initial certification in paragraph (d)(3) 
of this section an annual certification shall include the following:
    (A) Any updates to the best management practices plan.
    (B) An attachment of weekly flow measurements from the previous 
year.
    (C) The average amount of recycled bottom ash transport water in 
gallons per day.
    (D) Copies of annual inspection reports and a summary of 
preventative maintenance performed on the system.
    (E) A statement that the plan and corresponding flow records are 
being maintained at the office of the plant.
    (e) Requirements for low utilization boilers. (1) Initial and 
Annual Certification Statement. For sources seeking to apply the 
limitations or standards for low utilization boilers, an initial 
certification shall be made to the permitting authority with a permit 
application, or to the control authority no later than [DATE 3 YEARS 
AFTER DATE OF FINAL RULE] in the case of an indirect discharger, and an 
annual recertification shall be made to the permitting authority, or 
control authority in the case of an indirect discharger, within 60 days 
of submitting annual net generation data to the Energy Information 
Administration.
    (2) Contents. A certification or annual recertification shall be 
based on the information submitted to the Energy Information 
Administration and shall include copies of the underlying forms 
submitted to the Energy Information Administration, as well as any 
supplemental information and calculations used to determine the two 
year average annual net generation. Where station-wide energy 
consumption must otherwise be apportioned to multiple boilers, the 
facility shall attribute such consumption to each boiler proportional 
to that boiler's nameplate capacity unless the facility can demonstrate 
the energy consumption is specific to a boiler.
    (f) Requirements for units that will be retired from service by 
December 31, 2028 pursuant to Sec. Sec.  423.13(k)(2)(ii) and 
423.13(g)(1).
    (1) Initial Certification Statement. For sources seeking to apply 
the limitations or standards for units that will be retired from 
service by December 31, 2028, a one-time certification to the 
permitting authority must be submitted with the permit application, or 
where a permit has already been issued, by the as soon as possible date 
determined under paragraph 423.11(t), or to the control authority by 
[promulgation date + 3 years] in the case of an indirect discharger.
    (2) Contents. A certification shall include the estimated date that 
boiler will be retired from service, a brief statement as to the reason 
for retirement, as well as a copy of the most recent integrated 
resource plan, certification of boiler cessation under 40 CFR 
257.103(b), or other legally binding submission supporting that the 
boiler will be retired from service by December 31, 2028.
    (g) Requirements for facilities seeking the protections of Sec.  
423.18.
    (1) Certification Statement. For sources seeking to apply the 
protections of the permit conditions in Sec.  423.18, a one-time 
certification shall be submitted to the permitting authority, or 
control authority in the case of an indirect discharger, no later than 
30 days from receipt of the order or agreement attached pursuant to 
paragraph (f)(2) of this section.
    (2) Contents. A certification statement must demonstrate that a 
boiler would have qualified for the subcategory at issue absent the 
emergency order issued by the Department of Energy under Section 202(c) 
of the Federal Power Act or Public Utility Commission reliability must 
run agreement; and a copy of such order or agreement shall be attached.
[FR Doc. 2019-24686 Filed 11-21-19; 8:45 am]
BILLING CODE 6560-50-P