Air Plan Approval; Minnesota; Metropolitan Council Wastewater Treatment Plant Title I PM10 SIP Revisions

ENVIRONMENTAL PROTECTION AGENCY <CFR>40 CFR Part 52</CFR> <DEPDOC>[EPA-R05-OAR-2024-0268; FRL-12929-01-R5]</DEPDOC> <SUBJECT> Air Plan Approval; Minnesota; Metropolitan Council Wastewater Treatment Plant Title I PM <E T="0735">10</E> SIP Revisions </SUBJECT> <HD SOURCE="HED">AGENCY:</HD> Environmental Protection Agency (EPA). <HD SOURCE="HED">ACTION:</HD> Proposed rule. <SUM> <HD SOURCE="HED">SUMMARY:</HD> The Environmental Protection Agency (EPA) is proposing to approve a request from the Minnesota Pollution Control Agency (MPCA) to revise its State Implementation Plan (SIP) by updating information for the Metropolitan Council Environmental Service (MCES) Metropolitan Council Wastewater Treatment Plant (Metro Plant) in Ramsey County, Minnesota. This SIP revision is being proposed in conjunction with an amendment to a part 70 permit maintaining federally enforceable title I SIP conditions. This SIP revision would result in a reduction of allowable emissions of particulate matter less than 10 microns (PM <E T="52">10</E> ) emitted by the facility. </SUM> <EFFDATE> <HD SOURCE="HED">DATES:</HD> Comments must be received on or before December 22, 2025. </EFFDATE> <HD SOURCE="HED">ADDRESSES:</HD> Submit your comments, identified by Docket ID No. EPA-R05-OAR-2024-0268 at <E T="03">http://www.regulations.gov,</E> or via email to <E T="03">arra.sarah@epa.gov.</E> For comments submitted at <E T="03">Regulations.gov</E> , follow the online instructions for submitting comments. Once submitted, comments cannot be edited or removed from the docket. EPA may publish any comment received to its public docket. Do not submit to EPA's docket at <E T="03">https://www.regulations.gov</E> any information you consider to be Confidential Business Information (CBI), Proprietary Business Information (PBI), 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. EPA will generally not consider comments or comment contents located outside of the primary submission ( <E T="03">i.e.</E> on the web, cloud, or other file sharing system). For additional submission methods, please contact the person identified in the <E T="02">FOR FURTHER INFORMATION CONTACT</E> section. For the full EPA public comment policy, information about CBI, PBI, or multimedia submissions, and general guidance on making effective comments, please visit <E T="03">https://www.epa.gov/dockets/commenting-epa-dockets.</E> <FURINF> <HD SOURCE="HED">FOR FURTHER INFORMATION CONTACT:</HD> Nicole Naber, Air and Radiation Division (AR-18J), Environmental Protection Agency, Region 5, 77 West Jackson Boulevard, Chicago, Illinois 60604, (312) 886-6609, <E T="03">naber.nicole@epa.gov.</E> The EPA Region 5 office is open from 8:30 a.m. to 4:30 p.m., Monday through Friday, excluding Federal holidays. </FURINF> <SUPLINF> <HD SOURCE="HED">SUPPLEMENTARY INFORMATION:</HD> Throughout this document whenever “we,” “us,” or “our” is used, we mean EPA. <HD SOURCE="HD1">I. Background</HD> This proposed SIP revision affects the Metro Plant at 2400 Childs Road, Saint Paul, Minnesota. This facility utilizes three fluidized bed incinerators each using activated carbon, a baghouse, a wet scrubber, and a wet electrostatic precipitator to process wastewater solids and reduce PM <E T="52">10</E> emissions. The facility's permit contains site-specific restrictions as part of Minnesota's SIP for PM <E T="52">10</E> in the Red Rock Road PM <E T="52">10</E> Maintenance Area. This SIP currently contains non-expiring title I conditions from a part 70 permit issued for the facility (Permit No. 12300053-006), which establish emission limits and various conditions that were deemed essential to reach attainment for the 1987 National Ambient Air Quality Standards (NAAQS) for PM <E T="52">10</E> . This amendment to the MCES permit allows for the addition of a new emission unit, specifically an additional fluidized bed incinerator. To ensure the addition of this new unit will not cause a violation of the PM <E T="52">10</E> standard, an emission limit decrease and discontinuation of some emission units are being included in the permit revision. This permit revision results in a reduction of allowable PM <E T="52">10</E> emissions at the facility; therefore, the MPCA is requesting that EPA approve changes to the site-specific SIP for MCES (included in the Minnesota SIP at 40 CFR 52.1220). <HD SOURCE="HD1">II. Analysis of Minnesota's Submittal</HD> The purpose of Minnesota's permit action and related site-specific SIP revision is to address changes at the facility, specifically the addition of a fluidized bed incinerator, and decreases in other emission limits, many of which are affected by title I SIP conditions. This SIP revision is being proposed with an amendment to a part 70 permit maintaining federally enforceable title I SIP conditions (Air Emission Permit No. 12300053-102). The permit is final and was published on January 4, 2024, with an administrative amendment on March 6, 2024. MPCA provided EPA with detailed emissions information for each of the changes to the permit and SIP as well as the overall PM <E T="52">10</E> emission changes from the prior SIP submittal that EPA approved on September 11, 2002 (67 FR 57517), (associated with permit 12300053-006), to this submittal (associated with permit 12300053-102). This SIP revision incorporates several changes made in Permit No. 12300053-102 including lower allowable PM <E T="52">10</E> emissions at the facility through more stringent emissions limits on several pieces of equipment and processes. The limits for existing fluidized bed incinerators (FBIs) EQUI 3, EQUI 4, and EQUI 5 will be lowered from 2.01 pounds per hour (lbs/hr) PM <E T="52">10</E> to 1.70 lbs/hr PM <E T="52">10</E> on a 3-run average, as specified in permit conditions 5.7.13, 5.8.13, and 5.9.13. The limits for auxiliary boilers EQUI 10 and EQUI 11 will be lowered from 25.82 pounds per day (lbs/day) PM <E T="52">10</E> to 18.54 lbs/day PM <E T="52">10</E> on a 24-hour block average, as specified in permit condition 5.3.13. The limit for ash loadout housekeeping vacuum EQUI 50 will be lowered from 0.05 grains per dry standard cubic foot (gr/dscf) PM <E T="52">10</E> to 0.005 gr/dscf PM <E T="52">10</E> , on a 3-run average, as specified in permit condition 5.24.2. Finally, MCES will also use natural gas instead of fuel oil in EQUI 10 and EQUI 11 significantly lowering the PTE from 1.23 lbs/hr PM <E T="52">10</E> to 0.39 lbs/hr PM <E T="52">10</E> and will modify their ash handling equipment to meet the new proposed PM <E T="52">10</E> emission limit of 0.005 gr/dscf. The facility modeled these lower PM <E T="52">10</E> emissions limits in conjunction with equipment and operational limitations and the analysis showed a combined decrease of 6.3 tons per year in allowable emissions from the actions proposed in the title I SIP revision. The changes meet section 110(l) requirements since they are all decreases in emissions. The permit also includes changes that will not be incorporated into the SIP but are included in the docket as part of the submittal. These changes are still federally enforceable through non-expiring title I NAAQS synthetic minor conditions included in the facility's permit, under Minnesota's EPA-approved permit program. Specifically, these permit revisions include plans to build a fourth FBI (EQUI 133) and additional revisions such as rerouting of the pressure relief cycles. The potential to emit (PTE) from adding EQUI 133 and discontinuing EQUI 9 will be lowered from 14.08 lbs/hr to 9.22 lbs/hr. If MCES builds EQUI 133, it must also forfeit the construction and operation of three alkaline stabilization cells (EQUI 6, EQUI 7, EQUI 8). If MCES is unable to build the fourth FBI, MCES may continue with the previously permitted and SIP-approved construction and operation of three alkaline stabilization cells (EQUI 6, EQUI 7, EQUI 8). The facility provided modeling to demonstrate that these changes do not contribute to exceedances or violations of the PM <E T="52">10</E> standard which were assessed through the New Source Review program to ensure they meet Clean Air Act (CAA) requirements. Under section 110(l) of the CAA, EPA cannot approve a SIP revision if it would interfere with attainment of the NAAQS, reasonable further progress toward attainment, or any other applicable requirement of the CAA. Through this submittal, MPCA has demonstrated to EPA that 110(l) requirements have been met through the permit amendment and the successive SIP revision. The SIP revision shows a decrease in emissions and the permit changes have also been demonstrated to not interfere with attainment of the NAAQS. Therefore, EPA finds that Minnesota's permit action and successive SIP revision meet CAA requirements. <HD SOURCE="HD1">III. What action is EPA taking?</HD> EPA is proposing to incorporate into Minnesota's SIP all the conditions cited as “Title I Condition: 40 CFR 52.1220 (PM <E T="52">10</E> SIP)” in Permit No. 12300053-102. These revisions include both the changes in ash handling within the facility and the lower allowable PM <E T="52">10</E> emissions for each Fluidized Bed Incinerator (EQUI 3, EQUI 4, EQUI 5), auxiliary boilers (EQUI 10, EQUI 11), and ash loadout vacuum (EQUI 50). This SIP submittal includes Permit No. 12300053-102 and the supporting technical documentation. <HD SOURCE="HD1">IV. Incorporation by Reference</HD> In this rulemaking, EPA is proposing to include in a final EPA rule regulatory text that includes incorporation by reference. In accordance with requirements of 1 CFR 51.5, EPA is proposing to incorpora ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Preview showing 10k of 13k characters. Full document text is stored and available for version comparison. ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━