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Home My WebLink AboutNC0000396_Acknowledgement Letter_20220209ROY COOPER Governor ELIZABETH S. BISER Secretary S. DANIEL SMITH Director Duke Energy Progress, LLC Attn: Keith Douthit, Plant GM 46 Duke Energy Lane Arden, NC 28704 Subject: Permit Renewal Application No. NC0000396 Asheville Steam Electric Power Plant Buncombe County NORTH CAROLINA Environmental Quality November 16, 2021 Dear Applicant: The Water Quality Permitting Section acknowledges the November 16, 2021 receipt of your permit modification application and supporting documentation. Your application will be assigned to a permit writer within the Section's NPDES WW permitting branch. Per G.S. 150E-3 your current permit does not expire until permit decision on the application is made. Continuation of the current permit is contingent on timely and sufficient application for renewal of the current permit. The permit writer will contact you if additional information is required to complete your permit renewal. Please respond in a timely manner to requests for additional information necessary to allow a complete review of the application and renewal of the permit. Information regarding the status of your renewal application can be found online using the Department of Environmental Quality's Environmental Application Tracker at: https://deq.nc.gov/permits-regulations/permit-guidance/environmental-application-tracker If you have any additional questions about the permit, please contact the primary reviewer of the application using the links available within the Application Tracker. ec: WQPS Laserfiche File w/application D_E , Sincerely Wren Thdford Administrative Assistant Water Quality Permitting Section North Carolina Department of Environmental Quality I Division of Water Resources Asheville Regional Office 12090 U.S. Highway TO I Swannanoa. North Carolina 28778 828.296.4500 4‘ 'DUKE ENERGY® PROGRESS FedEx tracking: 775171340634 File: 12520B/ENV-30-32 November 10, 2021 Dr. Sergei Chernikov, PhD North Carolina Department of Environmental Quality Division of Water Resources 1617 Mail Service Center Raleigh, NC 27699-1617 Subject: Asheville Steam Electric Generating Plant NPDES Permit NC0000396 Request to modify NPDES permit Dear Dr. Chernikov: Keith Douthit Plant General Manager Asheville Combined Cycle Station Duke Energy Progress ASVL PLT 146 Duke Energy Lane Arden, NC 28704 o: 828-650-0620 t 828-650-0701 keith.douthit@duke-energy.com RECEIVED NOV 16 2021 NCDECIOWkINN4tS The Asheville Steam Electric Generating Plant coal units retired in January of 202Q concurrent to the natural gas combined cycle station completing commissioning. Decommissioning of the retired generation units are well underway. Excavation of the 1964 ash basin is proceeding well and is projected to be completed by the date required by the Mountain Energy Act. The final basin closure processes will require additions to and physical modifications of outfa11101. We do not anticipate the chemical characteristics of the typical releases from the modified outfall 101 to be different from the current discharge. As part of the final excavation and closure of the 1964 ash basin, Duke Energy will be installing underdrains to collect and direct groundwater within the footprint of the 1964 basin. A conceptual drawing identifying the location and extent of the underdrain system and its outlet pathway to outfall 101 is attached to the correspondence. Further, post -excavation stormwater flows will naturally drain to and be a component of outfall 101. These stormwater flows will consist of water from the former basin footprint and construction stormwater during the forthcoming construction project. The facility will be required to `notch" the 1964 ash basin dam such that it will not impound water. Flow volumes will be attenuated as required by local ordinance. We are respectfully requesting the description of outfall 101 in our NPDES permit application to be amended as follows: "Following excavation of the 1964 ash basin, outfall 101 flows will consist offlows from existing toe drains, groundwater removed via underdrains installed in the footprint of the 1964 ash basin and storm -water runoff." Dr. Sergei Chernikov NCDEQ Division of Water Resources November 10, 2021 Duke Energy requests that the NPDES permit be modified to include this updated description of outfall 101. A check in the amount of $1,030 is included for the modification fee. Should you have questions or need additional information please contact Don Safrit at 919-546-6146. Sincerely, Keith Douthit Asheville Plant Manager Attachments: A- Flow diagram B - Conceptual post closure diagram cc: Landon Davidson, DEQ, Asheville Regional Office - FedEx tracking 775171212080 Teresa Williams, Duke Energy Cynthia Winston, Duke Energy Don Safrit, Duke Energy Shannon Langley, Duke Energy .Dr. Sergei Chernikov NCDEQ Division of Water Resources November 10, 2021 Asheville Steam Electric Generating Plant NPDES Permit NC0000396 Attachment A — Flow Diagram French Broad River Make-up Water Settling Zone Lake Julian City of Asheville Public water Potable and Sanitary Systems Public Sewer System (MSD) Intake Structure Post Coal plant shutdown and Ash basin closure Q3.2022 Evaporation < Service water Fire Protection Power Block/Deme Industrial Storm Water Water truck du^,t suppression J Former1964 Ash Pond Dam Seepage Post closure stormwater Post closure groundwater Contact SW and tnterer.r;n' water X BB Lined Retention Peed EE Onsito Phycical/Chcmiclal WAS FF Note: All flow to LRB removed, LRB removed. post closure stormwater and groundwater to Outfall 101. Combined and Simple Cycle Plant GG - X — Secondary Settling Basin n A Segregated clean SW (potentially) French Broad River Outfall 101 Groundwater Extraction French Broad River Outfall 001 Attachment A— Process Flow Diagram Duke Energy Progress, LLC Asheville Steam Electric Plant Buncombe County October 2021 Lake Julian Intake Structure 2 Combined and Simple Cycle Combustion Turbine Plant 4 Existing Unit 3 and 4 Simple Cycle Deminerafzed Water Storage Tanks . Simple Cycle CTG Water Wash Transfer Truck Unit rRaw Water Supply // Simple Cycle CTG Water Injection . Evaporation 46 Ultrafiltration Backwash Strainer and ultrafiltration skids 8 Atmosphere 6 Service Water/Fire Water Tank 10 12 17 Service Water Users 16 38 Existing Simple Cycle Evap Cooling & Makeup Two -Pass Reverse Osmosis Standby RO/Demin Trailers Equipment Drains Sump 25 Existing Simple Cycle Stormwater Drains and lift station 38 13 14 OF Backwash Sump (Shared) Filter Press (Shared) A 44 Sludge Thickener (1 per power block) A 47 Transfer Truck 45 Cooling Tower & Basin Atmosphere 11 22 HRSG Blowdown Tank/Sump Mixed -Bed Demineralizer 15 v 18 21 20 37 t it 43. Side stream Filter Backwash Sump (1 per power block) 38 Side -Stream Filters ( per power b ock) 23 39 Unit 07/08 Cooling Tower — — Blowdown 001C i- 5 Unit 05/06 Cooling Tower Blowdown 001A An 24 HRSG 24 Sample Panel Demineralized Water Tanks Existing Outfall 002 to Lake Julian —* 19 CTG Wash Water CTG NOx Injection Transfer Truck 19 Wastewater Sump (Shared) 25 Unit 7/8 TB / WTB drains sump A 26 Existing Ash pond I RB / WTS Secondary Settling Basin Unit 5/6 TB drain sump J French Broad River Outfall 001 Ex isting Oil -Water Watater Separator Existing Fuel Oil Area Stormwater Attachment A - Process Flow Diagram Duke Energy Progress, LLC Asheville Steam Electric Plant Buncombe County. October 2021 Dr. Sergei Chernikov NCDEQ Division of Water Resources November 10, 2021 Asheville Steam Electric Generating Plant NPDES Permit NC0000396 Attachment B — Conceptual Post Closure Diagram Before Water Treatment Outfall 001 Asheville Plant Lined Retention Basin WASTE BOUNDARY Dam Breach After Underdrains Modified Outfall 101 - Post Closure, Pre -CAP Combined flows of underdrain, surface run-off And existing Outfall 101 1964 toe drains Cross section (existing condition with future pipe shown) Gravel underdrain Pipe (to be plac d Through dam Subsurface water urface water run off Gravel underdrain V Pipe (tbe placed) Throug dam Gravel underdrain to be placed in original channel at elevations where reformation occurs, pumped by wet well to LRB until Ash Basin Closure Profile view Wet well (prior to closure) Underdrain EllExcavated ash Surface water Surface water run off cavation d Toe drains / NPDES compliance Point Outfall 101 Wet well Notched dam Notched dam 70utfa11 101