[Federal Register Volume 81, Number 237 (Friday, December 9, 2016)]
[Proposed Rules]
[Pages 89026-89034]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2016-29236]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 63

[EPA-HQ-OAR-2012-0522; FRL-9956-00-OAR]
RIN 2060-AT14


Phosphoric Acid Manufacturing and Phosphate Fertilizer Production 
Risk and Technology Review

AGENCY: Environmental Protection Agency (EPA).

ACTION: Reconsideration; proposed rule.

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SUMMARY: This action proposes amendments to the National Emission 
Standards for Hazardous Air Pollutants (NESHAP) for the Phosphoric Acid 
Manufacturing and Phosphate Fertilizer Production source categories. 
The proposed amendments are in response to two petitions for 
reconsideration filed by industry stakeholders on the rule revisions to 
NESHAP for the Phosphoric Acid Manufacturing and Phosphate Fertilizer 
Production source categories that were promulgated on August 19, 2015 
(80 FR 50386) (hereafter the ``August 2015 Final Rule''). We are 
proposing to revise the compliance date by which affected sources must 
include emissions from oxidation reactors when determining compliance 
with the total fluoride (TF) emission limits for superphosphoric acid 
(SPA) process lines. We are also proposing to add a new option, and 
clarify an existing option, to the monitoring requirements for low-
energy absorbers. In addition, we are proposing to revise the 
compliance date for the monitoring requirements for low-energy 
absorbers.

DATES: Comments. Comments must be received on or before January 23, 
2017.
    Public Hearing. If anyone contacts the EPA requesting to speak at a 
public hearing by December 14, 2016, we will hold a public hearing on 
December 27, 2016 on the EPA campus at 109 T.W. Alexander Drive, 
Research Triangle Park, North Carolina.

ADDRESSES: Comments. Submit your comments, identified by Docket ID No. 
EPA-HQ-OAR-2012-0522, at http://www.regulations.gov. Follow the online 
instructions for submitting comments. Once submitted, comments cannot 
be edited or removed from Regulations.gov. 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 http://www2.epa.gov/dockets/commenting-epa-dockets.
    Instructions. Direct your comments to Docket ID No. EPA-HQ-OAR-
2012-0522. The EPA's policy is that all comments received will be 
included in the public docket without change and may be made available 
online at http://www.regulations.gov, including any personal 
information provided, unless the comment includes information claimed 
to be CBI or other information whose disclosure is restricted by 
statute. Do not submit information that you consider to be CBI or 
otherwise protected through http://www.regulations.gov or email. The 
http://www.regulations.gov Web site is an ``anonymous access'' system, 
which means the EPA will not know your identity or contact information 
unless you provide it in the body of your comment. If you send an email 
comment directly to the EPA without going through http://www.regulations.gov, your email address will be automatically captured 
and included as part of the comment that is placed in the public docket 
and made available on the Internet. If you submit an electronic 
comment, the EPA recommends that you include your name and other 
contact information in the body of your comment and with any disk or 
CD-ROM you submit. If the EPA cannot read your comment due to technical 
difficulties and cannot contact you for clarification, the EPA may not 
be able to consider your comment. Electronic files should not include 
special characters or any form of encryption and be free of any defects 
or viruses. For additional information about the EPA's public docket, 
visit the EPA Docket Center homepage at http://www.epa.gov/dockets.
    Docket. The EPA has established a docket for this rulemaking under 
Docket ID No. EPA-HQ-OAR-2012-0522. All documents in the docket are 
listed in the Regulations.gov index. Although listed in the index, some 
information is not publicly available, e.g., CBI or other information 
whose disclosure is restricted by statute. Certain other material, such 
as copyrighted material, is not placed on the Internet and will be 
publicly available only in hard copy. Publicly available docket 
materials are available either electronically in Regulations.gov or in 
hard copy at the EPA Docket Center, Room 3334, EPA WJC West Building, 
1301 Constitution Avenue NW., Washington, DC. The Public Reading Room 
is open from 8:30 a.m. to 4:30 p.m., Monday through Friday, excluding 
legal holidays. The telephone number for the Public Reading Room is 
(202) 566-1744, and the telephone number for the EPA Docket Center is 
(202) 566-1742.
    Public Hearing. A public hearing will be held, if requested by 
December 14, 2016, to accept oral comments on this proposed action. If 
a hearing is requested, it will be held at the EPA's North Carolina 
campus located at 109 T.W. Alexander Drive, Research Triangle Park, NC 
27711. The hearing, if requested, will begin at 10:00 a.m. (local time) 
and will continue until the earlier of 5:00 p.m. or 1 hour after the 
last registered speaker has spoken. To request a hearing, to register 
to speak at a hearing, or to inquire if a hearing will be held, please 
contact Ms. Pamela Garrett at (919) 541-7966 or by email at 
[email protected]. The last day to pre-register to speak at a 
hearing, if one is held, will be December 22, 2016. Additionally, 
requests to speak will be taken the day of the hearing at the hearing 
registration desk, although preferences on speaking times may not be 
able to be fulfilled. Please note that registration requests received 
before the

[[Page 89027]]

hearing will be confirmed by the EPA via email.
    Please note that any updates made to any aspect of the hearing, 
including whether or not a hearing will be held, will be posted online 
at https://www.epa.gov/stationary-sources-air-pollution/phosphate-fertilizer-production-plants-and-phosphoric-acid. We ask that you 
contact Pamela Garrett at (919) 541-7966 or by email at 
[email protected] or monitor our Web site to determine if a 
hearing will be held. The EPA does not intend to publish a notice in 
the Federal Register announcing any such updates. Please go to https://www3.epa.gov/ttn/atw/phosph/phosphpg.html for more information on the 
public hearing.

FOR FURTHER INFORMATION CONTACT: For questions about this proposed 
action, contact Ms. Susan Fairchild, Sector Policies and Programs 
Division (D243-02), Office of Air Quality Planning and Standards, 
Environmental Protection Agency, Research Triangle Park, North Carolina 
27711; telephone number: (919) 541-5167; email address: 
[email protected]. For information about the applicability of the 
NESHAP or the new source performance standards to a particular entity, 
contact Scott Throwe, Office of Enforcement and Compliance Assurance, 
U.S. Environmental Protection Agency, EPA WJC South Building, Mail Code 
2227A, 1200 Pennsylvania Avenue NW., Washington DC 20460; telephone 
number: (202)562-7013; and email address: [email protected].

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 the following terms and acronyms here:

CAA Clean Air Act
CBI Confidential business information
CFR Code of Federal Regulations
EPA U.S. Environmental Protection Agency
FR Federal Register
MACT Maximum achievable control technology
NAICS North American Industry Classification System
NESHAP National emission standards for hazardous air pollutants
OMB Office of Management and Budget
PRA Paperwork Reduction Act
RTR Risk and technology review
SPA Superphosphoric acid
TF Total fluoride
TFI The Fertilizer Institute
tpy Tons per year
UMRA Unfunded Mandates Reform Act

    Organization of this Document. The information in this preamble is 
organized as follows:

I. General Information
    A. Does this action apply to me?
    B. What action is the Agency taking?
    C. Where can I get a copy of this document and other related 
information?
    D. What is the Agency's authority for taking this action?
    E. What are the incremental cost impacts of this action?
II. Background
III. Discussion of the Issues Under Reconsideration
    A. What amendments are we proposing for oxidation reactors and 
what is the rationale?
    B. What amendments are we proposing for absorber monitoring and 
what is the rationale?
IV. Summary of Cost, Environmental, and Economic Impacts
V. Statutory and Executive Order Reviews
    A. Executive Order 12866: Regulatory Planning and Review and 
Executive Order 13563: Improving Regulation and Regulatory Review
    B. Paperwork Reduction Act (PRA)
    C. Regulatory Flexibility Act (RFA)
    D. Unfunded Mandates Reform Act (UMRA)
    E. Executive Order 13132: Federalism
    F. Executive Order 13175: Consultation and Coordination With 
Indian Tribal Governments
    G. Executive Order 13045: Protection of Children From 
Environmental Health Risks and Safety Risks
    H. Executive Order 13211: Actions Concerning Regulations That 
Significantly Affect Energy Supply, Distribution, or Use
    I. National Technology Transfer and Advancement Act (NTTAA)
    J. Executive Order 12898: Federal Actions To Address 
Environmental Justice in Minority Populations and Low-Income 
Populations

I. General Information

A. Does this action apply to me?

    Regulated Entities. Categories and entities potentially regulated 
by this action are shown in Table 1 of this preamble.

    Table 1--NESHAP and Industrial Source Categories Affected by This
                             Proposed Action
------------------------------------------------------------------------
                                                               NAICS \a\
                  NESHAP and source category                      code
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Phosphoric Acid Manufacturing................................     325312
Phosphate Fertilizer Production..............................
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\a\ North American Industry Classification System.

    Table 1 of this preamble is not intended to be exhaustive, but 
rather to provide a guide for readers regarding entities likely to be 
affected by the proposed action for the source category listed. To 
determine whether your facility is affected, you should examine the 
applicability criteria in the appropriate NESHAP. If you have any 
questions regarding the applicability of any aspect of this NESHAP, 
please contact the appropriate person listed in the preceding FOR 
FURTHER INFORMATION CONTACT section of this preamble.

B. What action is the Agency taking?

    The EPA is proposing amendments to 40 CFR part 63, subpart AA and 
40 CFR part 63, subpart BB in response to two petitions for 
reconsideration on the August 2015 Final Rule. One petition was filed 
by The Fertilizer Institute (TFI) and the other petition was filed by 
Phosphate Corporation of Saskatchewan, including: PCS Phosphate 
Company, Inc.; White Springs Agricultural Chemical, Inc., d/b/a PCS 
Phosphate-White Springs; and PCS Nitrogen Fertilizer, L.P., 
(collectively ``PCS''). The standards for the Phosphoric Acid 
Manufacturing source category are found in 40 CFR part 63, subpart AA, 
and the standards for the Phosphate Fertilizer Production source 
category are found in 40 CFR part 63, subpart BB.
    The petitions are available in the docket for this action (see 
docket items EPA-HQ-OAR-2012-0522-0084 and EPA-HQ-OAR-2012-0522-0085).
    For 40 CFR part 63, subpart AA, we are proposing to:
     Revise the compliance date by which affected sources must 
include emissions from oxidation reactors when determining compliance 
with the TF emission limits for SPA process lines from August 19, 2016, 
to August 19, 2018.
    For both 40 CFR part 63, subpart AA and 40 CFR part 63, subpart BB, 
we are proposing to:
     Clarify one option and include an additional option for 
determining the liquid-to-gas ratio of low-energy absorbers; and
     Revise the compliance date for this monitoring requirement 
from August 19, 2015, to August 19, 2017.
    In addition to the issues above, one petitioner, PCS, requested 
that the EPA reconsider the TF emission limits for phosphate rock 
calciners. However, PCS subsequently withdrew this request and this 
issue is no longer part of this reconsideration.
    The rationale for these proposed amendments is provided in section 
III of this preamble. This action is limited to the specific issues 
raised in the petitions for reconsideration. Therefore, we will respond 
only to comments addressing issues that were raised in the petitions

[[Page 89028]]

for reconsideration. There are no changes to emission limits as a 
result of these proposed amendments, and we expect the proposed 
additional compliance time for oxidation reactors will have an 
insignificant effect on a phosphoric acid manufacturing plant's overall 
emissions. As stated in the preamble to the August 2015 Final Rule, the 
EPA's technology review revealed that SPA process lines at four 
different facilities include an oxidation reactor to remove organic 
impurities from the acid. Hydrogen fluoride emissions from SPA process 
lines including oxidation reactors account for less than 1 percent of 
all hydrogen fluoride emissions from the source category. Consequently, 
the risk assessment in the August 2015 final risk and technology review 
(RTR) is unchanged by these proposed amendments.

C. Where can I get a copy of this document and other related 
information?

    In addition to being available in the docket, an electronic copy of 
this action will also be available on the Internet through the 
Technology Transfer Network (TTN) Web site, a forum for information and 
technology exchange in various areas of air pollution control. 
Following signature by the EPA Administrator, the EPA will post a copy 
of this proposed action at https://www.epa.gov/stationary-sources-air-pollution/phosphate-fertilizer-production-plants-and-phosphoric-acid. 
Following publication in the Federal Register, the EPA will post the 
Federal Register version and key technical documents on this same Web 
site.

D. What is the agency's authority for taking this action?

    The statutory authority for this action is provided by sections 112 
and 307(d)(7)(B) of the Clean Air Act (CAA) as amended (42 U.S.C. 7412 
and 7607(d)(7)(B)).

E. What are the incremental cost impacts of this action?

    There are 12 facilities in the United States that manufacture 
phosphoric acid; two of these make only phosphoric acid. There are 11 
operating facilities that produce phosphate fertilizers; one of these 
makes only fertilizer. While Phosphoric Acid Manufacturing and 
Phosphate Fertilizer Production are two different source categories, 10 
facilities manufacture both phosphoric acid and phosphate fertilizer, 
and are, therefore, considered to be in both source categories.\1\
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    \1\ These are 2014 data.
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    In this action, we have revised the estimated incremental cost 
impacts that were presented in the August 2015 Final Rule to reflect 
new information provided by TFI that takes into account the 
installation of an additional absorber at the Agrium Nu-West facility. 
Agrium Nu-West's costs are in addition to those for PCS Aurora, whose 
absorber installation costs were included in the August 2015 Final 
Rule. Each of these two facilities are in both the Phosphoric Acid 
Manufacturing and the Phosphate Fertilizer Production source 
categories. Table 2 of this preamble compares the overall total capital 
investment (TCI) and associated total annualized cost (TAC) from the 
August 2015 Final Rule and the revised total costs for the proposed 
reconsideration. Detailed information about these revised costs are 
provided in section IV of this preamble.

    Table 2--Comparison of Costs To Comply With August 2015 Final Rule, as Provided in 2015 and as Revised in
                                            Proposed Reconsideration
----------------------------------------------------------------------------------------------------------------
                                                      August 2015 final rule       2016 Proposed reconsideration
                                                 ---------------------------------------------------------------
                    Cost item                                          Total                           Total
                                                   Total capital    annualized     Total capital    annualized
                                                    investment         cost         investment         cost
----------------------------------------------------------------------------------------------------------------
Oxidation Reactor Absorber......................        $270,500         $95,300        $541,000        $243,400
Bag Leak Detection System.......................          75,600          29,700          75,600          29,700
Testing.........................................               0          98,400               0          98,400
Recordkeeping and Reporting.....................               0          70,600               0          70,600
                                                 ---------------------------------------------------------------
    Total.......................................         346,100         294,000         616,600         442,100
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II. Background

    On June 10, 1999 (64 FR 31358), the EPA promulgated 40 CFR part 63, 
subpart AA for the Phosphoric Acid Manufacturing source category and 40 
CFR part 63, subpart BB for the Phosphate Fertilizer Production source 
category. On August 19, 2015 (80 FR 50386), the EPA published amended 
rules for both of these source categories that took into consideration 
the technology review and residual risk review required by sections 
112(d)(6) and 112(f) of the CAA, respectively. In addition to other 
changes, the amendments revised the SPA process line definition in 40 
CFR part 63, subpart AA to include oxidation reactors and revised the 
monitoring provisions for low-energy absorbers in 40 CFR part 63, 
subpart AA and subpart BB to require monitoring of liquid-to-gas ratio 
rather than pressure drop. For more information on the final 
amendments, see 80 FR 50386.
    Following promulgation of the August 2015 Final Rule, the EPA 
received two petitions for reconsideration. On October 15, 2015, and 
October 16, 2015, TFI and PCS, respectively, requested administrative 
reconsideration of amended 40 CFR part 63, subpart AA and subpart BB 
under CAA section 307(d)(7)(B).
    TFI requested that the EPA reconsider: (1) The compliance schedule 
for requiring affected sources to include emissions from oxidation 
reactors when determining compliance with the TF emission limits for 
SPA process lines; (2) the compliance schedule for continuously 
monitoring the liquid-to-gas ratio for low-energy absorbers; (3) the 
regulatory language describing the option for using design blower 
capacity to determine the gas flow rate through the absorber for use in 
monitoring the liquid-to-gas ratio; and (4) other available options to 
determine the gas flow rate through the absorber for use in monitoring 
the liquid-to-gas ratio. PCS requested an administrative 
reconsideration of these same provisions, and also requested that the 
EPA reconsider the monitoring requirements for different types of low-
energy absorbers.
    We considered all the petitioners' requests, consolidated the 
similar issues

[[Page 89029]]

regarding alternative monitoring options for low-energy absorbers, and 
grouped the issues into the following three distinct topics:
     Compliance deadlines for air oxidation reactors that are 
within SPA lines;
     Monitoring options for low-energy absorbers;
     Compliance deadlines for low-energy absorbers.
    On December 4, 2015, the EPA granted reconsideration on all 
petitioners' issues pursuant to section 307(d)(7)(B) of the CAA (see 
docket items EPA-HQ-OAR-2012-0522-0086 and EPA-HQ-OAR-2012-0522-0087). 
CAA section 307(d)(7)(B) provides that the EPA shall convene a 
proceeding to reconsider a rule if a person raising an objection can 
demonstrate: (1) That it was impracticable to raise the objection 
during the comment period, or that the grounds for such objection arose 
after the comment period, but within the time specified for judicial 
review (i.e., within 60 days after publication of the final rulemaking 
notice in the Federal Register), and (2) that the objection is of 
central relevance to the outcome of the rule. We granted 
reconsideration on these specific issues because the grounds for 
petitioner's objections arose after the public comment period (but 
within the time specified for judicial review) and the objections are 
of central relevance to the outcome of the final rule pursuant to CAA 
section 307(d)(7)(B).

III. Discussion of the Issues Under Reconsideration

A. What amendments are we proposing for oxidation reactors and what is 
the rationale?

    In response to TFI's and PCS's requests to reconsider the 
compliance schedule for requiring affected sources to include emissions 
from oxidation reactors when determining compliance with the TF 
emission limits for SPA process lines, we are proposing to revise the 
compliance date from August 19, 2016, to August 19, 2018.\2\ As part of 
their request for reconsideration, TFI stated that one facility (Agrium 
Nu-West) had commenced an evaluation of how best to control its 
oxidation reactor emissions. The petitioner stated that this evaluation 
could result in Agrium Nu-West deciding to install an entirely new 
absorber for the oxidation reactor, which would involve permitting, 
budgeting, design, and construction. Agrium Nu-West subsequently 
provided additional details about its evaluation project, stating that 
they needed at least another 6 months to complete the installation of 
ductwork to redirect the exhaust from their existing oxidation reactor 
to an existing absorber. Agrium Nu-West also said that it would need 
more time to conduct performance testing in order to determine if the 
existing absorber could handle the additional emissions loading. If the 
performance testing demonstrated that the absorber is unable to meet 
the existing TF limits, Agrium Nu-West said it would need an additional 
24 to 36 months to install a new absorber on its oxidation reactor. 
Furthermore, both petitioners (TFI, the industry trade group, and PCS, 
the affected company which is also represented by TFI) confirmed that 
PCS Aurora will need to install a new absorber to achieve compliance 
with the SPA process line TF emission limit. PCS Aurora stated that 
they would need 24 months to install a new absorber on their oxidation 
reactors.
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    \2\ Refer to proposed footnote ``c'' of Tables 1 and 2 of 40 CFR 
part 63, subpart AA.
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    Both PCS Aurora and Agrium Nu-West provided the EPA with timelines 
(see docket item EPA-HQ-OAR-2012-0522-0088) detailing specific 
permitting, budgeting, design, and construction milestones that each 
facility would need to reach in order to comply with the requirement to 
control emissions from oxidation reactors for SPA process lines. The 
EPA determined that these milestones are necessary, and the estimated 
timelines are reasonable and are consistent with the timing allowed by 
CAA section 112(i)(3) (i.e., no more than 3 years after promulgation). 
Therefore, in order to allow time for permitting, budgeting, design, 
and construction, the EPA is proposing an additional 2-year compliance 
period by which affected sources must include emissions from oxidation 
reactors when determining compliance with the TF emission limits for 
SPA process lines. This extension provides a total of 3 years from 
promulgation to comply with the rule. This compliance period is the 
maximum amount of time that the CAA allows, and is consistent with 
similar rulemakings where facilities comply by installing add-on 
control equipment.

B. What amendments are we proposing for absorber monitoring and what is 
the rationale?

    In today's action, we are clarifying why we are retaining the 
requirement to monitor the liquid-to-gas ratio for low-energy 
absorbers. We have determined that liquid-to-gas ratio for low-energy 
absorbers is the most appropriate option to ensure proper TF control. 
For gaseous absorbers (such as those controlling TF), increasing the 
scrubbing liquid flow maximizes the liquid surface area available for 
absorption and normally favors a higher control efficiency (see docket 
item EPA-HQ-OAR-2012-0522-0089). The requirement to develop the minimum 
liquid-to-gas ratio during a performance test establishes the minimum 
amount of scrubbing liquid that is necessary to absorb the TF at the 
level necessary to achieve the standard under the operating conditions 
at which the performance test was conducted. At a constant gas flow 
rate, increasing the scrubbing liquid flow rate may result in better TF 
control, but decreasing the liquid flow rate may lead to insufficient 
absorption and reduce the control efficiency. The liquid-to-gas ratio 
provides an indication of whether enough scrubbing liquid (e.g., water) 
is present to provide adequate TF absorption for the amount of gas 
flowing through the system. As such, if the liquid-to-gas ratio is not 
monitored for low-energy absorbers, then sources cannot be certain an 
absorber is sufficiently controlling TF.
    In response to TFI's and PCS's request for reconsideration of the 
compliance schedule for continuously monitoring the liquid-to-gas ratio 
for low-energy absorbers, we are proposing to revise the compliance 
date for existing sources to no later than August 19, 2017. We are 
changing the compliance date in order to allow owners and operators 
additional time to obtain and certify the instruments needed to monitor 
liquid-to-gas ratio. Until this proposed compliance date, owners and 
operators must continue to demonstrate compliance by monitoring the 
influent absorber liquid flow rate and the pressure drop through the 
absorber, and conform to the applicable operating limit or range 
established using the methodologies in 40 CFR 63.605(d)(1) and 40 CFR 
63.625(d)(1).\3\
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    \3\ Refer to proposed footnote ``b'' of Table 3 of 40 CFR part 
63, subpart AA and of Table 3 of 40 CFR part 63, subpart BB.
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    Additionally, in response to TFI's and PCS's request for 
reconsideration of the regulatory language describing the option for 
using design blower capacity to determine the gas flow rate through the 
absorber for use in monitoring the liquid-to-gas ratio, we are 
proposing to clarify the procedure for using measured pressure drop and 
``design blower capacity'' to determine the gas flow rate through the 
absorber. Table 3 to subpart AA of 40 CFR part 63 currently requires 
owners and operators to monitor the liquid-to-gas ratio by measuring 
both the absorber inlet liquid flow rate, and inlet or outlet gas flow 
rate. However, the

[[Page 89030]]

rule also allows owners and operators the option to use measured 
pressure drop and ``design blower capacity'' to determine the gas flow 
rate through the absorber in lieu of direct measurement. Although we 
are retaining the requirement to monitor the liquid-to-gas ratio for 
low-energy absorbers, we are proposing to clarify and change the term 
``design blower capacity'' in Table 3 to subpart AA of 40 CFR part 63 
and Table 3 to subpart BB of 40 CFR part 63 to ``blower design 
capacity.'' We are proposing other minor text edits to these tables in 
order to use the phrase ``gas flow rate through the absorber'' more 
consistently. We are also proposing to insert footnote ``c'' into Table 
3 to subpart AA of 40 CFR part 63 and Table 3 to subpart BB of 40 CFR 
part 63 to clarify that the option to use blower design capacity is 
available regardless of the location of the blower (influent or 
effluent), as long as the gas flow rate through the absorber can be 
established. The blower design capacity option allows the owner or 
operator to determine a maximum possible gas flow rate through the 
absorber based on the blower's specifications. The owner or operator 
can monitor the influent liquid flow rate and use the maximum possible 
gas flow rate through the absorber to calculate the liquid-to-gas 
ratio. This option allows the owner or operator to reduce the 
monitoring requirements associated with the rule because the gas flow 
rate through the absorber is not required to be continuously monitored. 
However, if an owner or operator would like to have the flexibility to 
decrease the liquid flow rate through the absorber, the owner or 
operator can choose to monitor actual gas flow rate (along with liquid 
flow rate). As the gas flow rate decreases below the maximum possible 
gas flow rate, the minimum liquid flow rate required to achieve the 
minimum liquid-to-gas ratio also decreases.
    Furthermore, the intent to allow ``appropriate adjustments for 
pressure drop'' when blower design capacity is used, is to account for 
the effect of pressure drop on gas flow when establishing the maximum 
possible gas flow rate through the absorber under actual operating 
conditions using manufacturer information (e.g., a performance curve). 
The requirement is not intended to require continuous monitoring of the 
blower pressure drop. Because the pressure drop of the system changes 
the gas flow rate delivered by the blower, adjustments for pressure 
drop are required in cases where gas flow rate increases. We determined 
that it would not be technically appropriate to specify a single method 
for making this adjustment, because the method would vary depending on 
the design configuration of an individual gas handling system. However, 
to provide clarification (and to allow sources the flexibility to use 
best engineering judgment and calculations), we are proposing a 
requirement at 40 CFR 63.608(e) and 40 CFR 63.628(e) to document, in 
the site-specific monitoring plan, the calculations that were used to 
make adjustments for pressure drop if blower design capacity is used to 
establish the maximum possible gas flow rate through an absorber. 
Additional details and background on monitoring the liquid-to-gas ratio 
are included in the docket (see docket item EPA-HQ-OAR-2012-0522-0089 
and the guidance document, ``Clarification of Absorber Monitoring 
Requirements for National Emission Standards for Hazardous Air 
Pollutants (NESHAP)--Subparts AA and BB'' which is also available in 
the docket for this action).
    Also, in response to TFI's and PCS's requests for reconsideration 
of other available options to determine the gas flow rate through the 
absorber for use in monitoring the liquid-to-gas ratio, we are 
proposing to provide an additional option for determining the liquid-
to-gas ratio. Petitioners (TFI and PCS) took issue with the fact that 
the EPA did not consider other options (in lieu of direct measurement 
or using blower design capacity) for determining gas flow rate through 
the absorber. We acknowledge that there are other techniques for 
determining gas flow rate through an absorber (e.g., use of a damper 
setting to document a maximum gas flow rate through the absorber in 
lieu of the blower design capacity; back-calculating the gas flow rate 
by developing a correlation between static pressure and brake 
horsepower of the blower; or use of amperage of the blower as a 
surrogate). In particular, Mosaic Fertilizer, LLC (Mosaic) submitted to 
the EPA a case study (see ``Mosaic Case Study (Regression Model 
Example)'' available in the docket for this action) which 
simultaneously compared direct measurements of actual gas flow rate 
through an absorber to gas flow rates calculated using a regression 
model. The regression model that Mosaic used in this particular case 
study was developed using a design fan curve that correlates gas flow 
rate to static pressure (i.e., fan suction pressure) and brake 
horsepower of the blower. A paired t-test \4\ of the test data used in 
the case study reveals that there is a statistical difference between 
the gas flow rates that were directly measured and the gas flow rates 
that were calculated using the regression model; however, the 
regression model predicts a higher gas flow rate than was determined 
through direct measurement. A higher gas flow rate would require a 
higher liquid flow rate in order to maintain an established influent 
liquid-to-gas ratio operating limit; therefore, it is reasonable to 
conclude that the use of the regression model developed in this case 
study, in lieu of direct measurement, is a conservative method for 
determining gas flow rate through the absorber.
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    \4\ A paired t-test is a statistical tool used to compare one 
set of values with another set of values, by checking to see if 
their means are equivalent at a specified confidence level.
---------------------------------------------------------------------------

    In the Regression Model Example that is available in the docket for 
this action, the brake horsepower of a blower is calculated by 
multiplying the blower amperage by the blower's voltage and efficiency 
(which can both be determined from the blower's motor nameplate), a 
power factor (which can be determined using tables that list typical 
power factors for various size motors), a conversion factor, and, if 
necessary, a constant to correct for 3-phase power. The calculated 
brake horsepower is then used in the regression model along with the 
blower static pressure (i.e., fan suction pressure) to determine gas 
flow rate through an absorber. As a result of our considering the 
Mosaic case study, we are proposing to include an option in Table 3 to 
subpart AA of 40 CFR part 63 and Table 3 to subpart BB of 40 CFR part 
63 that allows facilities to develop and use a regression model, by way 
of a design fan curve that correlates gas flow rate to static pressure 
(i.e., fan suction pressure) and brake horsepower of a blower, to 
determine gas flow rate through an absorber (in lieu of direct 
measurement or using blower design capacity). If this option is used, 
we are proposing a requirement in footnote ``a'' of Table 4 to subpart 
AA of 40 CFR part 63 and Table 4 to subpart BB of 40 CFR part 63 that 
requires continuous monitoring of blower amperage, blower static 
pressure (i.e., fan suction pressure), and any other parameters used in 
the regression model that are not constants.
    We have not included equations that must be used in the regression 
model in order to allow owners and operators the flexibility to adjust 
this approach as necessary on a site-specific basis. As such, we are 
also proposing that the regression model must be developed using direct 
measurements of gas flow rate during a performance test, and then

[[Page 89031]]

annually checked via performance testing in order to ensure the 
correlation remains current and accurate. The annual regression model 
verification could be conducted during, or separately from, the annual 
performance testing that is required in the rule. To allow the 
flexibility to use best engineering judgment and calculations, we are 
proposing an annual requirement at 40 CFR 63.608(f) and 40 CFR 
63.628(f) to document, in the site-specific monitoring plan, the 
calculations that were used to develop the regression model and to 
require that the site-specific monitoring plan be updated annually to 
maintain accuracy and reflect data used in the annual regression model 
verification.
    Lastly, in response to PCS's request for reconsideration of 
monitoring requirements for different types of low-energy absorbers, we 
are proposing to insert footnote ``a'' into Table 3 to subpart AA of 40 
CFR part 63 and Table 3 to subpart BB of 40 CFR part 63 to remind 
affected entities that they can request an alternative monitoring 
method under the provisions of 40 CFR 63.8(f) on a site-specific basis. 
Such a request should include enough information to demonstrate the 
correlation between the selected operating parameter and gas flow rate 
through the absorber. Similarly, the petitioners also took issue that 
the EPA did not consider relevant design differences of low-energy 
absorbers such that the requirement to monitor the liquid-to-gas ratio 
may not be possible. In such cases, we are also proposing that the 
procedures at 40 CFR 63.8(f) be used to request to monitor an 
alternative operating parameter.

IV. Summary of Cost, Environmental, and Economic Impacts

    As part of their request for reconsideration (see docket item EPA-
HQ-OAR-2012-0522-0084), TFI notified the EPA that another facility 
(Agrium Nu-West) may also need to install an absorber in order to meet 
the SPA process line TF standard, when oxidation reactor emissions are 
included. The impacts for this other facility are in addition to those 
for PCS Aurora, whose absorber installation costs were included in the 
August 2015 Final Rule. Therefore, in this action, we are revising our 
estimate for overall TCI and associated TAC to comply with the August 
2015 Final Rule to take into account this additional absorber. Based on 
this revised analysis, we anticipate an overall TCI of $616,600, with 
an associated TAC of approximately $442,100. Similar to the August 2015 
Final Rule, these compliance costs also include estimates for all 
existing sources to add the necessary monitoring devices, conduct 
performance tests, and implement recordkeeping and reporting 
requirements to comply with the rules.
    Installing an absorber on the oxidation reactor at Agrium Nu-West 
will result in additional hydrogen fluoride emissions reductions of 
0.047 tons per year from the oxidation reactor (i.e., a reduction from 
0.049 tons per year to 0.002 tons per year(tpy)) and TF emissions 
reductions of 0.14 tpy from the oxidation reactor (i.e., a reduction 
from 0.147 tpy to 0.007 tpy). The details of the cost analyses and 
emissions reductions estimates are provided in the memorandum, 
``Control Costs and Emissions Reductions for Phosphoric Acid and 
Phosphate Fertilizer Production source categories--Reconsideration,'' 
which is available in the docket for this action. The economic impact 
associated with the revised cost estimate is an annualized control cost 
of about 0.01 percent of the parent company's annual revenues. The 
details on the economic impact analysis are provided in the memorandum, 
``Economic Impact Analysis for the Proposed Reconsideration of the 
National Emission Standards for Hazardous Air Pollutants: Phosphoric 
Acid Manufacturing and Phosphate Fertilizer Production source 
categories,'' which is available in the docket for this action.
    This action will have no other cost, environmental, energy, or 
economic impacts. This action primarily revises compliance dates 
specific to oxidation reactors in the Phosphoric Acid Manufacturing 
source category, and absorber monitoring in both the Phosphoric Acid 
Manufacturing and Phosphate Fertilizer Production source categories. 
The clarifications and other revisions we are proposing in response to 
reconsideration are cost neutral.

V. Statutory and Executive Order Reviews

    Additional information about these statutes and Executive Orders 
can be found at http://www2.epa.gov/laws-regulations/laws-and-executive-orders.

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

    This action is not a significant regulatory action and was, 
therefore, not submitted to the Office of Management and Budget (OMB) 
for review.

B. Paperwork Reduction Act (PRA)

    This action does not impose any new information collection burden 
under the PRA. OMB has previously approved the information collection 
activities contained in the existing regulations and has assigned OMB 
control number 2060-0361. With this action, the EPA is seeking comments 
on proposed amendments to the 40 CFR part 63, subpart AA and 40 CFR 
part 63, subpart BB that are mainly clarifications to existing rule 
language to aid in implementation issues raised by stakeholders, or are 
being made to allow more time for compliance. Therefore, the EPA 
believes that there are no changes to the information collection 
requirements of the August 2015 Final Rule, so that the information 
collection estimate of project cost and hour burden from the final 
rules have not been revised.

C. Regulatory Flexibility Act (RFA)

    I certify that this action will not have a significant economic 
impact on a substantial number of small entities under the RFA. This 
action will not impose any requirements on small entities. This action 
seeks comments on proposed amendments to the 40 CFR part 63, subpart AA 
and 40 CFR part 63, subpart BB that are mainly clarifications to 
existing rule language to aid in implementation issues raised by 
stakeholders, or are being made to allow more time for compliance.

D. Unfunded Mandates Reform Act (UMRA)

    This action does not contain any unfunded mandate as described in 
UMRA, 2 U.S.C. 1531-1538, and does not significantly or uniquely affect 
small governments. This action imposes no enforceable duty on any 
state, local, or tribal governments or the private sector.

E. Executive Order 13132: Federalism

    This action does not have federalism implications. It will not have 
substantial direct effects on the states, on the relationship between 
the national government and the states, or on the distribution of power 
and responsibilities among the various levels of government.

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

    This action does not have tribal implications, as specified in 
Executive Order 13175. It will not have substantial direct effects on 
tribal governments, on the relationship between the federal government 
and Indian tribes, or on the distribution of power and responsibilities 
between the federal government and Indian tribes, as specified in 
Executive Order 13175.

[[Page 89032]]

Thus, Executive Order 13175 does not apply to this action.

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

    This action is not subject to Executive Order 13045 because it is 
not economically significant as defined in Executive Order 12866, and 
because the EPA does not believe the environmental health or safety 
risks addressed by this action present a disproportionate risk to 
children. This action seeks comments on proposed amendments to the 40 
CFR part 63, subpart AA and 40 CFR part 63, subpart BB that are mainly 
clarifications to existing rule language to aid in implementation 
issues raised by stakeholders, or are being made to allow more time for 
compliance. We expect the proposed additional compliance time for 
oxidation reactors will have an insignificant effect on a phosphoric 
acid manufacturing plant's overall emissions. Hydrogen fluoride 
emissions from SPA process lines including oxidation reactors account 
for less than 1 percent of all hydrogen fluoride emissions from the 
source category. Therefore, the proposed amendments should not 
appreciably increase risk for any populations.

H. Executive Order 13211: Actions Concerning Regulations That 
Significantly Affect Energy Supply, Distribution, or Use

    This action is not subject to Executive Order 13211 because it is 
not a significant regulatory action under Executive Order 12866.

I. National Technology Transfer and Advancement Act (NTTAA)

    This action does not involve any new technical standards from those 
contained in the August 2015 Final Rule. Therefore, the EPA did not 
consider the use of any voluntary consensus standards.

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

    The EPA believes that this action does not have disproportionately 
high and adverse human health or environmental effects on minority 
populations, low-income populations, and/or indigenous peoples, as 
specified in Executive Order 12898 (59 FR 7629, February 16, 1994).
    The environmental justice finding in the August 2015 Final Rule 
remains relevant in this action, which seeks comments on proposed 
amendments to these rules that are mainly clarifications to existing 
rule language to aid in implementation issues raised by stakeholders, 
or are being made to allow more time for compliance. We expect the 
proposed additional compliance time for oxidation reactors will have an 
insignificant effect on a phosphoric acid manufacturing plant's overall 
emissions. Hydrogen fluoride emissions from SPA process lines including 
oxidation reactors account for less than 1 percent of all hydrogen 
fluoride emissions from the source category. Therefore, the proposed 
amendments should not appreciably increase risk for any populations.

List of Subjects in 40 CFR Part 63

    Environmental protection, Administrative practice and procedure, 
Air pollution control, Hazardous substances, Reporting and 
recordkeeping requirements.

    Dated: November 28, 2016.
Gina McCarthy,
Administrator.
    For the reasons stated in the preamble, the Environmental 
Protection Agency proposes to amend title 40, chapter I, of the Code of 
Federal Regulations as follows:

PART 63--NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS 
FOR SOURCE CATEGORIES

0
1. The authority citation for part 63 continues to read as follows:

    Authority:  42 U.S.C. 7401 et seq.

Subpart AA--National Emission Standards for Hazardous Air 
Pollutants from Phosphoric Acid Manufacturing Plants

0
2. Section 63.608 is amended by adding paragraphs (e) and (f) to read 
as follows:


Sec.  63.608   General requirements and applicability of general 
provisions of this part.

* * * * *
    (e) If you use blower design capacity to determine the gas flow 
rate through the absorber for use in the liquid-to-gas ratio as 
specified in Table 3 to this subpart, then you must include in the 
site-specific monitoring plan specified in paragraph (c) of this 
section calculations showing how you determined the maximum possible 
gas flow rate through the absorber based on the blower's specifications 
(including any adjustments you made for pressure drop).
    (f) If you use a regression model to determine the gas flow rate 
through the absorber for use in the liquid-to-gas ratio as specified in 
Table 3 to this subpart, then you must include in the site-specific 
monitoring plan specified in paragraph (c) of this section the 
calculations that were used to develop the regression model, including 
the calculations you use to convert amperage of the blower to brake 
horsepower. You must describe any constants included in the equations 
(e.g., efficiency, power factor), and describe how these constants were 
determined. If you want to change a constant in your calculation, then 
you must conduct a regression model verification to confirm the new 
value of the constant. In addition, the site-specific monitoring plan 
must be updated annually to reflect the data used in the annual 
regression model verification that is described in Table 3 to this 
subpart.
0
3. Table 1 to subpart AA of part 63 is amended by revising footnote 
``c'' to read as follows:

  Table 1 to Subpart AA of Part 63--Existing Source Emission Limits a b
------------------------------------------------------------------------
 
-------------------------------------------------------------------------
 
                               * * * * *
------------------------------------------------------------------------
\c\ Beginning on August 19, 2018, you must include oxidation reactors in
  superphosphoric acid process lines when determining compliance with
  the total fluorides limit.

* * * * *
0
4. Table 2 to subpart AA of part 63 is amended by revising footnote 
``c'' to read as follows:

    Table 2 to Subpart AA of Part 63--New Source Emission Limits a b
------------------------------------------------------------------------
 
-------------------------------------------------------------------------
 
                               * * * * *
------------------------------------------------------------------------
\c\ Beginning on August 19, 2018, you must include oxidation reactors in
  superphosphoric acid process lines when determining compliance with
  the total fluorides limit.

0
5. Table 3 to subpart AA of part 63 is amended by:
0
a. Revising the column headings ``And you must monitor. . .'' and
    ``And. . .'' by including a reference to footnote a;
0
b. Revising the entry ``Install CPMS for liquid and gas flow at the 
inlet of the absorber''; and
0
c. Adding footnotes ``a'' through ``d'' to read as follows:

[[Page 89033]]



                   Table 3 to Subpart AA of Part 63--Monitoring Equipment Operating Parameters
----------------------------------------------------------------------------------------------------------------
                                                                 And you must monitor .
            You must . . .                     If . . .                 . . \a\               And . . . \a\
----------------------------------------------------------------------------------------------------------------
 
                                                  * * * * * * *
Install CPMS for liquid and gas flow   Your absorber is         Liquid-to-gas ratio as   You must determine the
 at the inlet of the absorber \b\.      designed and operated    determined by dividing   gas flow rate through
                                        with pressure drops of   the influent liquid      the absorber by:
                                        5 inches of water        flow rate by the gas    Measuring the gas flow
                                        column or less; or       flow rate through the    rate at the absorber
                                       Your absorber is          absorber. The units of   inlet or outlet;
                                        designed and operated    measure must be         Using the blower design
                                        with pressure drops of   consistent with those    capacity, with
                                        5 inches of water        used to calculate this   appropriate
                                        column or more, and      ratio during the         adjustments for
                                        you choose to monitor    performance test.        pressure drop; \c\ or
                                        the liquid-to-gas                                Using a regression
                                        ratio, rather than                                model.\d\
                                        only the influent
                                        liquid flow, and you
                                        want the ability to
                                        lower liquid flow with
                                        changes in gas flow.
 
                                                  * * * * * * *
----------------------------------------------------------------------------------------------------------------
\a\ To monitor an operating parameter that is not specified in this table (including process-specific techniques
  not specified in this table to determine gas flow rate through an absorber), you must request, on a site-
  specific basis, an alternative monitoring method under the provisions of 40 CFR 63.8(f).
\b\ For existing sources, if your absorber is designed and operated with pressure drops of 5 inches of water
  column or less, the compliance date is August 19, 2017. In the interim, for existing sources with an absorber
  designed and operated with pressure drops of 5 inches of water column or less, you must install CPMS for
  pressure at the gas stream inlet and outlet of the absorber, and monitor pressure drop through the absorber.
\c\ If you select this option, then you must comply with Sec.   63.608(e). The option to use blower design
  capacity is intended to establish the maximum possible gas flow through the absorber; and is available
  regardless of the location of the blower (influent or effluent), as long as the gas flow rate through the
  absorber can be established.
\d\ If you select this option, then you must comply with Sec.   63.608(f). The regression model must be
  developed using direct measurements of gas flow rate during a performance test, and design fan curves that
  correlate gas flow rate to static pressure (i.e., fan suction pressure) and brake horsepower of the blower.
  You must conduct an annual regression model verification using direct measurements of gas flow rate during a
  performance test to ensure the correlation remains accurate. The annual regression model verification may be
  conducted during, or separately from, the annual performance testing that is required in Sec.   63.606(b).

0
6. Table 4 to subpart AA of part 63 is amended by revising the entry 
``Influent liquid flow rate and gas stream flow rate'' to read as 
follows:

 Table 4 to Subpart AA of Part 63--Operating Parameters, Operating Limits and Data Monitoring, Recordkeeping and
                                             Compliance Frequencies
----------------------------------------------------------------------------------------------------------------
                                      You must        And you must monitor, record, and demonstrate continuous
  For the operating parameter      establish the          compliance using these minimum frequencies . . .
applicable to you, as specified      following     -------------------------------------------------------------
        in Table 3 . . .         operating limit .                                         Data averaging period
                                        . .          Data measurement    Data recording       for compliance
----------------------------------------------------------------------------------------------------------------
 
                                                  * * * * * * *
Influent liquid flow rate and    Minimum influent   Continuous.......  Every 15 minutes.  Daily.
 gas stream flow rate.            liquid-to-gas
                                  ratio \a\.
 
                                                  * * * * * * *
----------------------------------------------------------------------------------------------------------------
\a\ If you select the regression model option to monitor influent liquid-to-gas ratio as described in Table 3 to
  this subpart, then you must also continuously monitor (i.e., record every 15 minutes, and use a daily
  averaging period) blower amperage, blower static pressure (i.e., fan suction pressure), and any other
  parameters used in the regression model that are not a constant.

Subpart BB--National Emission Standards for Hazardous Air 
Pollutants From Phosphate Fertilizers Production Plants

0
7. Section 63.628 is amended by adding paragraphs (e) and (f) to read 
as follows:


Sec.  63.628   General requirements and applicability of general 
provisions of this part.

    (e) If you use blower design capacity to determine the gas flow 
rate through the absorber for use in the liquid-to-gas ratio as 
specified in Table 3 to this subpart, then you must include in the 
site-specific monitoring plan specified in paragraph (c) of this 
section calculations showing how you determined the maximum possible 
gas flow rate through the absorber based on the blower's specifications 
(including any adjustments you made for pressure drop).
    (f) If you use a regression model to determine the gas flow rate 
through the absorber for use in the liquid-to-gas ratio as specified in 
Table 3 to this subpart, then you must include in the site-specific 
monitoring plan specified in paragraph (c) of this section the 
calculations that were used to develop the regression model, including 
the calculations you use to convert amperage of the blower to brake 
horsepower. You must describe any constants included in the equations 
(e.g., efficiency, power factor), and describe how these constants were

[[Page 89034]]

determined. If you want to change a constant in your calculation, then 
you must conduct a regression model verification to confirm the new 
value of the constant. In addition, the site-specific monitoring plan 
must be updated annually to reflect the data used in the annual 
regression model verification that is described in Table 3 to this 
subpart.
0
8. Table 3 to subpart BB of part 63 is amended by:
0
a. Revising the column headings ``And you must monitor. . .'' and 
``And. . .'' by including a reference to footnote a;
0
b. Revising the entry ``Install CPMS for liquid and gas flow at the 
inlet of the absorber''; and
0
c. Adding footnotes ``a'' through ``d'' to read as follows:

                   Table 3 to Subpart BB of Part 63--Monitoring Equipment Operating Parameters
----------------------------------------------------------------------------------------------------------------
                                                                 And you must monitor .
            You must . . .                     If . . .                  . .\a\                And . . .\a\
----------------------------------------------------------------------------------------------------------------
 
                                                  * * * * * * *
Install CPMS for liquid and gas flow   Your absorber is         Liquid-to-gas ratio as   You must determine the
 at the inlet of the absorber \b\.      designed and operated    determined by dividing   gas flow rate through
                                        with pressure drops of   the influent liquid      the absorber by:
                                        5 inches of water        flow rate by the gas    Measuring the gas flow
                                        column or less; or       flow rate through the    rate at the absorber
                                       Your absorber is          absorber. The units of   inlet or outlet;
                                        designed and operated    measure must be         Using the blower design
                                        with pressure drops of   consistent with those    capacity, with
                                        5 inches of water        used to calculate this   appropriate
                                        column or more, and      ratio during the         adjustments for
                                        you choose to monitor    performance test.        pressure drop; \c\ or
                                        the liquid-to-gas                                Using a regression
                                        ratio, rather than                                model.\d\
                                        only the influent
                                        liquid flow, and you
                                        want the ability to
                                        lower liquid flow with
                                        changes in gas flow.
 
                                                  * * * * * * *
----------------------------------------------------------------------------------------------------------------
\a\ To monitor an operating parameter that is not specified in this table (including process-specific techniques
  not specified in this table to determine gas flow rate through an absorber), you must request, on a site-
  specific basis, an alternative monitoring method under the provisions of 40 CFR 63.8(f).
\b\ For existing sources, if your absorber is designed and operated with pressure drops of 5 inches of water
  column or less, the compliance date is August 19, 2017. In the interim, for existing sources with an absorber
  designed and operated with pressure drops of 5 inches of water column or less, you must install CPMS for
  pressure at the gas stream inlet and outlet of the absorber, and monitor pressure drop through the absorber.
\c\ If you select this option, then you must comply with Sec.   63.628(e). The option to use blower design
  capacity is intended to establish the maximum possible gas flow through the absorber; and is available
  regardless of the location of the blower (influent or effluent), as long as the gas flow rate through the
  absorber can be established.
\d\ If you select this option, then you must comply with Sec.   63.628(f). The regression model must be
  developed using direct measurements of gas flow rate during a performance test, and design fan curves that
  correlate gas flow rate to static pressure (i.e., fan suction pressure) and brake horsepower of the blower.
  You must conduct an annual regression model verification using direct measurements of gas flow rate during a
  performance test to ensure the correlation remains accurate. The annual regression model verification may be
  conducted during, or separately from, the annual performance testing that is required in Sec.   63.626(b).

0
9. Table 4 to subpart BB of part 63 is amended by revising the column 
headings and entry for ``Influent liquid flow rate and gas stream flow 
rate'' to read as follows:

 Table 4 to Subpart BB of Part 63--Operating Parameters, Operating Limits and Data Monitoring, Recordkeeping and
                                             Compliance Frequencies
----------------------------------------------------------------------------------------------------------------
                                      You must        And you must monitor, record, and demonstrate continuous
                                   establish the          compliance using these minimum frequencies . . .
  For the operating parameter        following     -------------------------------------------------------------
applicable to you, as specified   operating limit
        in Table 3 . . .            during your                                            Data averaging period
                                  performance test   Data measurement    Data recording       for compliance
                                       . . .
----------------------------------------------------------------------------------------------------------------
 
                                                  * * * * * * *
Influent liquid flow rate and    Minimum influent   Continuous.......  Every 15 minutes.  Daily.
 gas stream flow rate.            liquid-to-gas
                                  ratio \a\.
 
                                                  * * * * * * *
----------------------------------------------------------------------------------------------------------------
\a\ If you select the regression model option to monitor influent liquid-to-gas ratio as described in Table 3 to
  this subpart, then you must also continuously monitor (i.e., record every 15 minutes, and use a daily
  averaging period) blower amperage, blower static pressure (i.e., fan suction pressure), and any other
  parameters used in the regression model that are not a constant.

[FR Doc. 2016-29236 Filed 12-8-16; 8:45 am]
BILLING CODE 6560-50-P