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Home My WebLink AboutNC0038377_NPDES Permit Modification Letter 3-12-2021_20211215DUKE ENERGY File: Mayo12520-R March 12, 2021 Sergei Chernikov, PhD. North Carolina Division of Environmental Quality 1617 Mail Service Center Raleigh, NC 27699-16I7 Subject: Duke Energy Progress, LLC. Mayo Electric Generating Plant NPDES Permit NC0038377 Permit Modification Request Dear Dr. Chernikov: Mayo Steam Plant Duke Energy Progress 10660 Boston Road Roxboro. NC 27574 Duke Energy Progress, LLC. is requesting a modification of the Mayo Steam Station's NPDES permit to make the following changes: 1. Duke Energy requests that landfill leachate from the CCR landfill being constructed to comply with terms of the settlement agreement in the matter of Superior Court 13 CVS 11032 be identified as a contributing flow to the lined retention basin. Potential leachate data based on Mayo samples from wells located in the vicinity of the ash pond is included as Attachment 1, to illustrate the expected leachate characterization. The leachate volume generated by the new landfill will vary over time but is expected to be approximately 50,000 gallons per day during the initial phases of development and reducing over time. Only water conditioned ash will be placed in the new CCR landfill. Duke Energy requests an increase in the flow limit from the dewatering system during dewatering activities and requests establishment of an internal outfall to allow reporting of the dewatering system flow limit specified in the permit. The flow limit from the dewatering system currently is 2.0 MGD daily maximum. However, the ash basin is influenced by a large drainage area during rain events. Duke Energy requests that the flow limit be increased to 3.0 MGD and expressed as a monthly average similar to the flow requirement at our Belews Creek facility. Additionally, the permit currently states that this flow limit is applicable to interstitial water only but does not provide a mechanism to report that data and demonstrate compliance. 3. Duke requests removal of Outfalls 004, 005, 006c, 006d and 006e from the permit. Outfalls 004 and 005 have been re-routed and now discharge as a part of Outfall 002. Permit NC0038377 Modification Request March 12, 2021 Outfalls 006c, 006d and 006e have been grouted closed and no longer have the potential to discharge. 4. Duke Energy requests a permit application update to include addition of ammonia conversion maintenance drainage as a contributing flow to the lined retention basin. The Mayo Station has two Selective Catalytic Reactors (SCR) for NO), control. An ammonia stripping column will be added per SCR utilizing aqueous ammonia as the reagent. Periodic maintenance and or unit shutdown periods, will require the column contents to be drained. Each column could have a maximum of 740 gallons of water with ammonia concentration less than 1.0 ppm with the pH being controlled in the system with caustic. The column contents would be drained to the lined retention basin for treatment discharging at internal Outfall 002A and then ultimately to Outfall 002 to Mayo Reservoir. A process narrative description is attached and hereby included in our application on file. 5. Duke Energy requests the sampling frequency for the domestic package plant (internal Outfall 011) be updated to quarterly to better align with system design and the permit requirements at the Roxboro Steam Plant. The Mayo package plant discharges an estimated 12,000 gallons per day through the internal outfall and has demonstrated compliance through weekly sampling since the permit's current effective date. 6. Duke Energy requests the addition of industrial stormwater from the new CCR landfill to be added as a contributing flow to the lined retention basin before discharging to Mayo Reservoir via Outfall 002. A check in the amount of $1,030 is included for the permit modification review fee. Should you have any questions please contact Ms. Lori Tollie at Lori.Tollie@duke- eneray.com or at (336)-854-4916. Sincerely, Tom Copolo General Manager - Mayo Steam Station DA2157 DUKE ENERGY BUSINESS SERVICES LLC 400 S TRYON STREET ACCOUNTS PAYABLE - 5T258 CHARLOTTE, NC 28202 000012 1:13K1SDA NORTH CAROLINA DEPARTMENT OF ENVIRONMENTAL QUALITY DIVISION OF WATER RESOURCES 1617 MAIL SERVICE CENTER RALEIGH NC 27699-1617 Remittance Advice Page 1 of 1 Date: 03/09/2021 Check #: 1000186408 Payment Amount: 1,030.00 Vendor #: 0000071949 Invoice Date 03/08/2021 Invoice # MY0003082021 Voucher ID k 11625028 Invoice Gross Amt 1,030.00 Discount Amount 0.00 Invoice Net Amt 1,030.00 PLEASE DETACH BEFORE DEPOSITING CHECK CHECK CONTAINS MULTIPLJ_ FFIAtJD DETERRENT SECURITY FEATURES DUKE ENERGY BUSINESS SERVICESLLC 400 5 TRYON STREET ACCOUNTS PAYABLE - ST2SB CHARLOTTE, NC 28202 Pay Exactly **One Thousand Thirty and 00/100 -US Dollars** TO THE ORDER OF NORTH CAROLINA DEPARTMENT OF ENVIRONMENTAL QUALITY JP MORGAN CHASE BANK, N A. SYRACUSE, NY 13206 50-937/211 Date: 03/09/2021 Check #: 1000186408 Amount $****1,030.00 VOID AFTER 19a DAYS A thorized signer 6 ++'i0001864080 1:02i3093791: 60/84656ill' Requesting a check If you want me to request a check for you, I need the following information from you: Vendor's Name and Contract Number NCDEQ Division of Water Resources Vendor's Address 1617 Mail Service Center Raleigh, NC 27699-1617 If the address is not in the system, I'll also need phone number to request that address to be added. Amount $1030 Who will approve request? Cynthia Winston Description of what check is for NPDES Major Modification Application Fee Mayo Steam Station To whom shall I send the check? (most checks I request are to be sent to an employee to send to the vendor) Give name and mail code Leanne Wilson 10660 Boston Road Roxboro, NC 27573 GL BU MY00 Oper Unit 20003 Resp Center 6494 Account 0108640 Resource Type 69100 EITHER a process OR project and activity Process NA Project and Activity AMY010238 Terms (when do you want the check — currently we can ask for a check in 0 days) 3/9/2021 2014.06-04 Environmentalservices(\\nt000062)Administrative\adminasst\forms\requestingacheck Cesk‘RicA Mo:k 3I/' Oa() pogo 000l flags 033 '.3t.C.cR5 At Sr, Corn i U.00, Qh CJ.