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HomeMy WebLinkAboutNC0005088_Modification (Admendment)_20210108 f' DUKE Rogers Energy Complex 573 Duke Power Road „ ' ENERGY® Mooresboro, NC 28114 January 8, 2021 RECEIVED Sergei Chernikov, PhD �� gED North Carolina Department of Environmental Quality JAN Division of Water Resources 1 2021 1617 Mail Service Center NCDEQ/D�/ R/ - 7 NP Raleigh, NC 27699 161 DE$ Subject: Rogers Energy Complex NPDES Permit NC0005088 Amendment to pending NPDES permit modification request Dear Dr. Chernikov: Duke Energy hereby submits an amendment to the January 15th, 2020 NPDES permit modification request for the subject facility. Specific modification requests are highlighted in bold throughout this submittal. Duke Energy request that NPDES permit# NC0005088 be modified to incorporate adopted steam electric Federal Effluent Guidelines found in 40 CFR Part 423. Duke Energy requests that the amended concentration limits for FGD wastewater found in the modified rule be incorporated into the permit. Those limits are as follows with changes from the existing permit limits highlighted: Pollutant Existing monthly average/daily max Modified ELG monthly average/daily max Arsenic 8 ug/I and 11/ug/I 8 ug/I and 18 ug/I Mercury 356 ng/I and 788 ng/I 34 ng/I and 103 ng/I Selenium 12 ug/I and 23 ug/I 19 ug/I and 70 ug/I Nitrate/Nitrite 4.4 mg/I and 17 mg/I 3 mg/I and 4 mg/I Duke Energy requests a 6-month extension of the FGD wastewater compliance date to June 30, 2022. Duke Energy is actively constructing the wastewater treatment system to treat flows from the FGD blowdown waste stream. Construction timeframes have been expedited significantly to comply with the current NPDES permit compliance date of December 31, 2021. The anticipated completion of construction is approximately July 2021. This new system will consist of advanced physical/chemical components along with biological treatment for removal of selenium. Based on our operating and startup experience with these systems at other stations (e.g. Roxboro, Marshall, Allen and Belews Creek), this short extension is needed to allow for adequate time to properly start up the biological components and have them reach optimum treatment performance levels. The biological components require significant time to , • Dr. Sergei Chernikov North Carolina Department of Environmental Quality flivisinn of Water RPsniirr.Ps January 6, 2021 reach these treatment levels. Commissioning of the system at both Roxboro and Marshall took approximately six months after the bioreactor was seeded, before the system was functioning at optimum levels. This request is supported by the timeframe estimates in our original requests for compliance schedule dated August 31, 2016 and supports the Division's intent to expedite the original proposed compliance dates of December 31, 2023 in an NPDES permit that was placed at public notice. Duke Energy requests that the temperature monitoring upstream and downstream of Outfall 005 be removed from the permit. Duke Energy has submitted the report required by permit condition A. (27) to verify the CORMIX modeling assumptions on which the 100°F daily maximum temperature limit was based. This report was submitted on August 25, 2020. Given this, and the upstream and downstream sampling data submitted to date (also analyzed in the report), the100°F daily maximum effluent limitation is sufficient to assure that the instream 89.6°F maximum and 5.04°F delta thermal standards are not exceeded outside the defined mixing zone. As discussed, and confirmed with NC DWR staff prior to submittal, this submittal is an update to an existing permit modification request for which the appropriate fee was previously submitted, therefore no check is included with this submittal. if you have questions, please contact Robert Wylie at (704) 562-8258 or robert.wylie@duke-energy.com. Sincerely, 6h„. Jeff Joyce, General Manager II Rogers Energy Complex cc: Robert Wylie - via email Steve Hodges Shannon Langley — via email