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Home My WebLink AboutNC0000396_Modification_20211116 -1 STAT�4 . ROY COOPER Governor - ELIZABETH S.BISER Secretary S.DANIEL SMITH NORTH CAROLINA Director Environmental Quality November 16, 2021 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 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. 150B-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. Sincerely Wren Th dford Administrative Assistant Water Quality Permitting Section ec: WQPS Laserfiche File w/application North Carolina Department of Environmental Quality I Division of Water Resources Asheville Regional Office 2090 U.S.Highway 70 I Swannanoa.North Carolina 28778 n';w A^W vd 828.296.4500 �' DUKE Keith Douthit ENERGY® Plant General Manager Asheville Combined Cycle Station PROGRESS Duke Energy Progress ASVL PLT 146 Duke Energy Lane FedEx tracking: 775171340634 Arden,NC28704 o: 828-650-0620 File: 12520B/ENV-30-32 E 828-650-0701 keith.douthit@duke-energy.com November 10, 2021 Dr. Sergei Chernikov, PhD North Carolina Department of Environmental Quality Division of Water Resources RECEIVED 1617 Mail Service Center Raleigh, NC 27699-1617 N O V 16 2021 NCDEQIDVVRINV[)tS Subject: Asheville Steam Electric Generating Plant NPDES Permit NC0000396 Request to modify NPDES permit Dear Dr. Chernikov: The Asheville Steam Electric Generating Plant coal units retired in January of 2021 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 wetland 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 outfal1101. 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,outfal1101 flows will consist of flows from existing toe drains, groundwaterremovedvia underdrains installed in the footprint of the 1964 ash basin and storm-water runoff." Dr.Sergei Chemikov 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 Chemikov NCDEQ Division of Water Resources November 10,2021 Asheville Steam Electric Generating Plant NPDES Permit NC0000396 Attachment A—Flow Diagram Post Coal plant shutdown and Ash basin closure Q3.2022 Note: All flow to LRB removed, French Broad River Intake LRB removed, post closure Structure ' stormwater and groundwater to i > Outfall 101. Make-up O Service Water > Water v ' Settling N Zone I E Fire Preteotion L-ined Q X > Retent4en D Pend v n Power v V Blesk/Deme K Combined Lake Industrial Storm and Simple Cycle Julian Water X Plant v -_ Water truck dust J EE c reeciea V Oncito GG French Broad City of Physical/Chemical X Secondary > River Asheville Settling Basin Public S Outfall 001 water Contact SW and A A Former 1964 Ash tnterc+;+; i water 1 evaporation < Pond X BB FF Potable and c i X Segregated clean SW(potentially) Sanitary Systems W V Dam Seepage French Broad Public Sewer Post closure stormwater > River Attachment A—Process Flow Diagram System (MSD) Post closure groundwater Outfall 101 Duke Energy Progress, LLC Groundwater men Asheville Steam Electric Plant Buncombe County October 2021 Combined and Simple Cycle Combustion Turbine Plant 1 2 4 Ultrafiltration 8 10 16 25 Intake Backwash Strainer Service Water/Fire Service Equipment Lake Structure > >� > and ultrafiltration --� Water Tank > Water Users > Drains Sump > Julian skids Existing 17 Outfall Existing Simple Cycle Existing Simple Cycle Lake002 to 5 > Evap Cooling& i► Stormwater er Drains Makeup and lift station Julian 3 38 38 Unit 07/08 Raw\ Standby RO/Demin > Water Supply > Trailers 9 12 Existing Unit 3 and 4 Simple 13 _ _ 15 V 18 A Simple Cycle _i. Cycle CTG Two-Pass Reverse Mixed-Bed Demineralized CTG NOx Demineralized Water Water > Osmosis > Demineralizer > Water Tanks —� / Storage Tanks Injection Injection 6 • • Atmosphere < 14 D Simple Cycle Evaporation > 20 CTG Water I Atmosphere < Wash V 22 19 1 > 11 21 Transfer Truck Cooling Tower& > HRSG Blowdown < HRSG 4— > Basin Tank/Sump • A V OF Backwash Sump > tf I 24 I CTG Wash (Shared) 45 I 23 24 YmY� Water Transfer Truck Sample A 37 38 39 Panel 19 44 I ;~ Unit 07/08El if Cooling Tower -- �✓ Unit 7/8 TB/ 43 ♦ yl Blowdown \ ~— WTB drains sump Sludge Side-stream Filter Side-Stream 001C 4 Thickener(1 per <-- - Filters(1 per Backwash Sump i power block) power block) *__ Unit 5/6 TB 46 f (1 per power drain sump block) 5 25 v 47 Unit 05/06 —Y-- Filter Press Secondary French Broad River (Shared) _ Cooling Tower Wastewater Sump > Settling > 001A > (Shared) A 26 Basin Outfall 001 T ting Existing Fuel Oil Fuel ) Transfer Truck ( Fuel Oil Oil-Water Area Separator Stormwater Existing Ash pond LRB I WTS 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 Asheville Plant After Water Treatment Outfall 001 Lined Retention Basin Underdrains F. • • WASTE BOUNDARY 1 •` 1 . `''` -¢ \`+ WASTE BOUNDARY M ' sue �„ H w ,f7 ° H _ A .` ` { I � b _1y t • .1 ti,7f , ik 1 \ i?I 4r �� 4 `.... ;!I ■ �. „�. t,, �:, -' —.. ii I ,.. 1 -'441 : , µ 4 Former 126 t ` r 196d ASH PQND' • ,126 kk k' : 1954 ASH POND INS, �n�' r 4 :�' \ \ , \ k� -L', 0004, Outfalt 101 1 i\ 1 Ilk L'''.' ,,="j \ ‘ N ` 0 1964 Dam Toe Drain , 1 l� ., :Awe' \Niii, 1 AL ),,,,,,41imploP" cr . 4r • \ , N 1,./..? ‘ , . _,..._ / IC Dam Breach Modified Outfall 101 - Post Closure, Pre-CAP Combined flows of underdrain, surface run-off And existing Outfall 101 1964 toe drains • • Profile view Surface water run off Cross section (existing condition with future pipe shown) Dam (lowered with spillways) nsta le. after a,cavation s. ffro mm Y6"'z� d''" .t (to be cove -d) �, �. , ,��, / As toI �� Wet well Toe drains (prior to closure) NPDES compliance Point Outfall 101 Surface ° ater run off . Plan view • urface water run off ® underdrain Final Grade � Gravel Gravel ❑ Excavated ash underdrain underdrain Gravel underdrain • Pipe(to be plac•d) Pipe(t. be placed) Through dam Subsurface water Throug dam Surface watern off Wet well 11, Gravel underdrain to be placed in original channel at elevations where reformation occurs, pumped by wet well to LRB until Ash Basin Closure. Notched dam Notched dam Outfall 101