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HomeMy WebLinkAboutNC0000396_RA_Supplemental Info_20171207e7f� DUKE GarryA Whisnant �►, ENERGY® Plant General Manager PROGRESS Asheville Steam Electric Plant Duke Energy Progress Certified Mail. 7016 2140 0001 0231 0671 ASVL PLT 1200 CP&L Dt Arden, NC 28704 File. 12520A o 828-687-5201 t 828-687-5204 December 7, 2017 garry whisnant@duke-energy com Mr. Jeff Poupart NCDENR, Division of Water Resources 1617 Mail Service Center Raleigh, NC 27699-1617 RECEI ED/DENR/DWR Subject Duke Energy Progress, Inc DEC A 5 2017 Asheville Steam Electric Generating Plant dieter Resources Supplemental to NPDES Perrmt Renewal Application Permitting Section NPDES Permit No. NC0000396 Buncombe County Dear Mr Poupart: Duke Energy Progress, LLC (Duke) is submitting supplemental information in support of the Asheville Steam Electric Plant's NPDES permit renewal application This submittal is in addition to the previous renewal application and permit modification requests submitted. Please see Table 1 for submittal history Duke is requesting that the information provided in all of these submissions be included during the permit renewal process. Information is provided for a modified process flow path to Outfall 001, removal of the 1982 ash basin, and options for closure of the 1964 ash basin Revised site and flow diagrams are attached. We appreciate your attention to these requests and look forward to finalizing the NPDES permit for the Asheville Steam mn'the near future Should you have any questions regarduig this letter or require additional information, please contact Ms. Tina Woodward at (704) 382-4585 or at Tina Woodward@Duke-Energy.com. 1 certify, underpenalty of law, that this document and all attachments were prepared tinder my direction or supervision in accordance with a system designed to assure that qualified personnel properly gather and evaluate the information submitted Based on my inquiry of the person or persons who manage the system, or those persons directly responsible for gathering the information, the information submitted is, to the best of my knowledge and belief, true, accurate, and complete I ant aware that there are significant penalties for submitting false information, including the possibility of fines and imprisonment for knowing violations Sincerely, A17-YA /--," Garry Whisnant Plant Manager Asheville Steam Plant Duke Energy Progress, Inc Asheville Steam Electric Generating Plant Supplemental to NPDES Permit Renewal Application NPDES Permit No NC0000396 Buncombe County Table 1 - NPDES Permit No. NC000396 Submittal History Date Title/Activity 06/11/2010 Submitted to DEQ Permit Renewal Application 09/29/2010 Sent requested 2007-2008 Environmental Monitoring Report for Lake Julian to DEQ. 05/13/2011 Received DEQ approval to relocate outfall 001 11/01/2011 Administrative update to permit application six (6) chemical additions 10/11/2012 Administrative update to permit application one (1) chemical addition 07/30/2014 Submitted to DEQ update to renewal application 02/04/2015 Submitted to DEQ Chemical characterization of water for dewater of the ash basins 07/22/2015 Submitted to DEQ notice of pending wastewater treatment facility - Wetlands Demolition 02/01/2016 Submitted to DEQ notice of pending wastewater treatment facility - Removal of Duck Pond and Installation of Filters 09/28/2016 DEQ Effluent Channel Visit 12/01/2016 Submitted to DEQ Supplemental to Permit Renewal Application Enclosures: Supplemental Information Package Attachment A — 1982 Ash Basin Dam Breach Letter Attachment B — NPDES Outfalls Attachment C — Process Flow Diagrams Attachment D — Flow, Sources of Pollution, and Treatment Technologies cc: Sergei Cherenkov Complex NPDES Permit Supervisor 1617 Mail Service Center Raleigh, NC 27699-1617 Landon Davidson Asheville Regional Office Supervisor 2090 U.S. Highway 70 Swannanoa, NC 28778 Duke Energy Progress, LLC. Asheville Steam Electric Plant NPDES Permit # NC0000396 Supplemental Information Package Introduction and Background Duke Energy Progress, I.I.C. Asheville Steam Electric Plant NPDES PERMIT # NC0000396 Supplemental Information Package Duke Energy Progress, LLC. (Duke) is submitting this additional supplemental information in support of the pending NPDES permit renewal for the Asheville Steam Electric Plant (Plant) This submittal is intended to provide alternatives for closure of the 1964 ash basin that will be necessary to comply the Federal Coal Combustion Residual (CCR) rule, the North Carolina Coal Ash Management Act of 2014, HB 630 of 2016 and the Senate Bill 716. Mountain Energy Act of 2015. Supplemental information is also provided for the following: 1. Removal of the former 1982 ash basin as a wastewater treatment structure. 2. A modified process flow path to Outfall 001. 3. Clarification to the Steam Electric Effluent Limitation Guidelines 4. A discussion on the dewatering of the 1964 basin. In total, there will remain two final outfalls to waters of the State: Outfalls 001 and 002. The process flows to Outfall 001 have changed and these changes have been documented with the Division of Water Resources, NPDES regulatory permitting agency'as described below. There are no changes to Outfall 002; therefore, that outfall is not discussed in this supplemental information packet. (See attachment B entitled NPDES Outfalls) Revised site and flow diagrams are included in Attachment C. Removal of the former 1982 Ash Basin from the NPDES Program The 1982 Ash Basin was constructed in 1982 with the establishment of a dam (BUNCO -089) in the valley adjacent to the 1964 Ash Basin. The 1982 Ash Basin reached capacity in 2007, and an ash excavation plan was developed to increase ash storage capacity. The excavated ash was transported to the Asheville Regional Airport (Airport) for the airport's taxiway infrastructure. The 1982 Ash Basin has been dewatered, Page 1 of 7 November 2017 Duke Energy Progress, LLC Asheville Steam Electric Plant NPDES PERMIT # NC0000396 Supplemental Information Package and approximately 4.1 million tons of ash have been excavated and transported to the Airport for a structural fill project in accordance with the Asheville Plant's ash reuse permit (Distribution of Residual Solids (503 Exempt) Permit Number WQ0000020). Ash placement at the last structural fill project (Airport Area III) was completed on July 17, 2015. Loading and transportation of ash from the 1982 Ash Basin to the R&B Landfill in Homer, GA began on October 15, 2015 and to the onsite landfill at the Rogers Energy Complex (Cliffside) on February 29, 2016 Excavation of the 1982 Ash Basin was completed on September 30, 2016, and the Basin was turned over for dam decommissioning and the construction of a natural gas combined cycle plant after an independent qualified professional engineer concluded that primary source ash had been removed from the basin as verified by visual observation methods in accordance with Duke Energy's Coal Combustion Residual (CCR) Removal Verification Procedure. All former water inflows into the 1982 Ash Basin were re-routed to the open water area in the 1964 Basin. Stormwater that collected naturally on the 1982 basin or water from a Department of Transportation (DOT) culvert has been rerouted via underdrains to facilitate the construction of the combined cycle plant On August 23, 2017, the engineer of record determined the basin had been filled to the prescribed level and the embankment lowered in general accordance with the approved plans. The 1982 Ash Basin Dam Breach Letter is included as attachment A. For these reasons, Duke is requesting the removal of the -1982 ash basin from the permit. Outfa11001 Current Condition The 1964 Ash Basin Dam (BUNCO -097) was constructed in 1964 to serve as a wastewater treatment facility for the treatment of ash sluice water. The surface area of the basin is approximately 45 acres. The basin does not retain a permanent pool with the exception of a three -acre unlined retention pond known as the open water area. All ash wastes are expected to be removed completely from the 1964 ash basin by applicable regulatory deadlines. The Plant's remaining ash basin (hereinafter referred to as the 1964 ash basin), is located east of the French Broad River, south of the plant and discharges into the French Broad River. With the Page 2 of 7 November 2017 Duke Energy Progress, I.I.C. Asheville Steam Electric Plant NPDES PERMIT # NC0000396 Supplemental Information Package approval of the North Carolina Department of Environmental Quality (NC DEQ), Duke relocated treated waters from the former 1982 ash basin and lined rim ditch to a downstream outfall location (Outfall 001) on the French Broad River. The relocation of Outfall 001 was necessary to allow for enhancement to the dam of the 1964 ash basin to meet current engineering standards. Production ash is sluiced to a concrete rim ditch system that is located within the footprint of the 1964 Ash Basin. The rim ditch system also receives plant stormwater drainage and low volume wastewater. CCR are dredged from the rim ditch, dewatered, and transported off-site. Historically, the wastewater from the rim ditch process was treated in the lined rim ditch system, then routed to the open water area, and decanted to a settling pond outside of the 1964 Ash Basin. The settling pond serves as the monitoring point for Outfall 001 of the Plant's NPDES permit. Water discharge from this settling pond is routed directly to the French Broad River through a permitted outfall. During 2016, wastewater flows and treatment were adjusted to facilitate the excavation of the 1982 Ash Basin The center pond filters were constructed at the end of the rim ditch and commissioned to replace the treatment provided by the open water area. Infrastructure was developed to dewater the open water area to the head of the rim ditch, and subsequently, the low volume waste and stormwater that flowed into the 1982 Ash Basin and pumped to the rim ditch was re-routed to the open water area. The ash basin and/or rim ditch provides treatment by sedimentation and neutralization to the plant's waste streams Water leaves the rim ditch via weirs and curtains to the lined center pond where a skimmer pulls water into 1 of 4 filter trains and flows via either the 1964 ash pond or direct discharge to a lined stilling pond, where the discharge is treated by an automated pH system, where it is then discharged by overflow to a pipe that coveys it to the French Broad River. Toe drains from the 1964 basin are currently collected and pumped to the rim ditch and flow through the treatment system to outfall 001 and the French Broad River. Duke Energy has requested that the toe drains be included in the reissued permit as separate outfalls. If they are included as such in the new permit, upon permit issuance, toe drain flows may be released to the French Broad River. Flue Gas Desulfurization Blowdown (Low Volume Waste) Page 3 of 7 November 2017 Duke Energy Progress, LLC. Asheville Steam Electric Plant NPDES PERMIT # NC0000396 Supplemental Information Package This system is currently discharging to the Metropolitan Sewerage District (MSD) from the waste water treatment building. The Flue Gas Desulfurization (FGD) system directs flue gas into an absorber where a limestone (calcium carbonate) slurry is sprayed. Sulfur dioxide in the flue gas reacts with the limestone to produce calcium sulfate (gypsum). This system reclaims any unreacted limestone slurry to be reused in the absorber. A small blowdown stream is used to maintain the chloride concentration in the reaction tank. The blowdown stream is passed through a clarifier to remove solids and reduce the chloride concentration in the waste stream. Chemicals are used to adjust pH and to aid solids removal in the clarifier. The waste stream enters a weir box and is discharged into a connection to MSD. 9964 Ash Basin Pre -closure Wastewater Duke Energy is in the process of excavating ash from the 1964 ash basin which will continue through plant retirement no later than January 31, 2020 and subsequent closure. It is anticipated that interstitial water will be encountered early in the process as portions of the 1964 ash basin are being excavated. Duke Energy plans to place the interstitial water discovered within the 1964 basin into the Rim Ditch and treat as necessary to ensure compliance with permit limits prior to discharging through Outfall 001. It is Duke Energy's understanding that this activity is permitted under North Carolina's NPDES wastewater permit program, because the contents of this basin is regulated as a wastewater until leaving the treatment basin for disposal or beneficial use. Prior to moving the wastewater into the rim ditch, Duke will assure that (i) all NPDES permit terms and conditions are being met; and (ii) any necessary dam safety approvals are secured and that the work is being done in accordance with applicable dam safety guidelines and requirements. For these reasons, Duke is requesting that the proposed intra basin wastewater handling be permitted under North Carolina's NPDES wastewater permit program. Steam Electric Effluent Limitation Guidelines Clarification On December 1, 2016, Duke Energy submitted a justification for the appropriate applicability dates for compliance with the 2015 revisions to the Steam Electric Effluent Limitation Guidelines (2015 ELG Rule) for the Plant. The justification demonstrated that the appropriate applicability date to comply with the more stringent best available technology (BAT) limits for flue gas desulfurization (FGD) wastewater and bottom ash transport water (BATW) was January 31, 2020 However, on September 18, 2017, U.S. EPA issued a November 2017 Page 4 of 7 Duke Energy Progress, I.I.C. Asheville Steam Electric Plant NPDES PERMIT # NC0000396 Supplemental Information Package final rule postponing the earliest compliance date for the more stringent BAT limits for BATW and FGD wastewater until November 1, 2020 (82 Fed. Reg 43,494 (Sept. 18, 2017)). As a result of this final rule, Duke request an applicability date of November 1, 2020 for the no discharge limit of bottom ash transport water and the limits for arsenic, mercury, nitrate/nitrite and selenium for FGD wastewater. 1964 Water Treatment Options - Post Asheville Coal Fired Plant Closure The 1964 Ash Basin is currently void of free-standing water, except for the small open water area (described above). Stormwater and wastewater flows into the open water area are captured and pumped to the head of the rim ditch wastewater treatment system within the footprint of the 1964 Ash Basin. As noted above, the settling treatment provided by the open water area was replaced by a filtration system. The filtration system meets existing permit requirements as it relates to the treatment previously provided by the open water area The treated wastewater continues to flow to the permitted NPDES Outfall 001. The open water area is used for retention of the 1964 Basin and the low volume stormwater and wastewater flows. Contact and interstitial water from the 1964 Ash Basin excavation will also be pumped to the rim ditch wastewater treatment system, including filtration until station retirement and demolition of the rim ditch. In order to facilitate compliance with the NPDES permit, Duke Energy has developed two options to accomplish dewatering and ultimately closure of the 1964 ash basin. Flow diagrams and Form 2C tables for the preferred options are included in Attachments C and D, respectively Option A - Onsite Treatment Only November 2017 Page 5 of 7 Duke Energy Progress, I.I.C. Asheville Steam Electric Plant NPDES PERMIT # NC0000396 Supplemental Information Package Option A involves the installation of two fully redundant treatment trains Each treatment train would treat 400 to 500 gpm flows, removing suspended solids and associated metals. One treatment train could be eliminated in the future once LVWS is eliminated by demolition, which is tentatively scheduled for August 2021. This option will also include a lined settling basin (side hill basin) to segregate the LVWS that is a non -CCR waste stream from the 1964 basin. This option may also require a tank by the treatment plant to equalize interstitial water and 1964 basin stormwater flows as described in Option B. Option B - Hybrid Option that includes onsite treatment as well as Low Volume Wastes and incidental stormwater disposal to the MSD Option B includes development of a single 400 to 500 gpm mobile treatment system for placement inside or outside the basin. This system would remove suspended solids and associated metals from post operational flows and dewatering flows from the contractor's water management sumps. A tank, of approximately 200,000 -gallon capacity may be needed to equalize flows to the treatment system. A dedicated lined equalization basin within the 1964 Basin (side hill basin) would be used to settle out suspended solids and to equalize flow for direct discharge to the MSD, should a modified SIU permit be acceptable to MSD. November 2017 Page 6 of 7 Duke Energy Progress, LLC Asheville Steam Electric Plant NPDES PERMIT# NC0000396 Supplemental Information Package List of Attachments: Attachment A -1982 Ash Basin Dam Breach Letter Attachment B — NPDES Outfalls Attachment C — Process Flow Diagrams — Current State — Option A — Option B Attachment D — Form 2C - Item II - A Flow, Sources of Pollution, and Treatment Technologies — Current State — Option A — Option B November 2017 Page 7 of 7 Attachment A - 1982 Ash Basin Dam Breach Letter f V6�1 September 7, 2017 amec ]- foster Mr Michael G. Clough, P.E. wheeler Lead Engineer Duke Energy 400 South Tryon Street Charlotte, North Carolina 28202 Subject: 1982 Ash Basin Dara Breach Letter Asheville Steam Electric Generating Plant Amec Foster Wheeler Project No.: 7810160620 Dear Mr. Clough Duke Energy Progress is In the process of breaching the Asheville Steam Electric Generating Plant -1982 Basin Dam (BUNCO -089) according to the plans approved in February 2016 by North Carolina Department of Environmental Quality — Dam Safety Division. On August 23, 2017, Amec Foster Wheeler representative (Luke Williams, engineer of record) visited the site and observed that the basin had been filled to the prescribed level and the embankment lowered in general accordance with these approved plans. As such the structure will not impound water of sufficient volume to be subject to the Emergency Action Plan requirements Additional work to fulfill the remaining requirements of the approved breach plans are still ongoing (ditches, final grading, topsoiling, etc ) Once this work is completed, as -constructed plans will be submitted for fulfillment of decommissioning the dam If you have any questions regarding this submittal do not hesitate to contact us. Sincerely, Amec Foster Wheeler Environment & Infrastructure, Inc. Luke C. Williams P.E. Senior Consultant Jill Heimburg, PE Senior Engineer 2/ Project Manager Amec Foster Wheeler Environment & Infrastructure Inc 2801 Yorkmont Road, Suite 100 Registered in North Carolina Charlotte, North Carolina 28208 Engineering and Land Surveying License No F-1253 704-357-8600 Geology License No C-247 amecfw com Attachment B - NPDES Outfalls L1.! .. t r 1 ' •'rrww , w, `-mow♦ d +i ' 't 9� �'R:;. a • r e. �. ! iR' I • • iP- •R{Y•Rr, ~� fit jr St dxr' tt.:.. �� Via. • '+ ,• .. ♦ !!s •�{u ^Y l,f - a r R � J'� r� �J �� � t � P''� .�. �rY yrs{ � �'�" �� • � �'°' r -.;e. d + yam.. _ "' Y _ � �' d . M �'�.��✓'9� ,� a " } 4 y w z JSy. J_f � f ! •{ � � � ^� t J' d S' 'W.r t � ° ! { } ,5:." { + ! 1 tr ,. `�F � � �".! .„ 3 •sir ".r ,.p�� • • �'.l.Ii '4. a ,.'' � � ' � t � t �... ^�v,':i � ., I R ' f 40 ♦ J .. / ,fes r' ��}t, • 1 Outfall 001 - •� #rte - Lake Julian l a. r ♦ f � � '• +4 ' ..,. * fit^ bSt-- •.'+i! ?i � � �- � �'` Outfall 002 n �.. +, + . • •� i `_ ;• NX r "�a`.+, a'k F ti l�}fir ., .e • � • •♦. N 660 330 0 660 1,320 1,980 Feet r s Attachment B — Outfall Locations Carolina Power & Light Company Asheville Steam Electric Plant Buncombe County October 2016 Attachment C - Process Flow Diagrams French Broad River D Lake N Julian I U Public Water Supply Make -Up Water Intake X Settling Zone B Intake Structure Service Water 17-rrent Consumptive Bier Loss StormwateF 19V Uh Pond utormwater flow ha been redirected dare Seepa4- Flue Gas Desulfurization V Clarifier j Ultra -Filtration System 1 & 2 S Lake Julian nsers Outfall 002: Public Circulating Water IF to Heat Exchanger luocl T Fire Fire 'um AA Protection System System ► Ash Sump O Vendor supplied water treatment Combustion M Turbine Site '—I intema4 Low Volume 71 E Storm Water — Groundwater Extraction (Option B) ; Potable and C Public 4. Sanitary Sewer System System a 1964 f- --.._ _________ Ash Pond Rim Ditch & Secondary French Broad (Duck Pond) Polishing Filter Settling River Basin A Outfall 001 (Future Flow) 1 J1 H �___ Temporary Phys/Chem J Groundwater Extraction Coal Pile (Option A) Runoff Dam Seepage Attachment C —Process Flow Diagram Duke Energy Progress LLC Evaporation Sewer System ► Ash Sump MSD intema4 ; Preheater Ash Evaporati n Cleaning Sluice L in Boiler a, Water Water L i LL 1 R Chemical Metal Cleaning Waste ; ; G ; 1 ; (Alt.) 1 , ------ ----------J Z 1 1964 f- --.._ _________ Ash Pond Rim Ditch & Secondary French Broad (Duck Pond) Polishing Filter Settling River Basin A Outfall 001 (Future Flow) 1 J1 H �___ Temporary Phys/Chem J Groundwater Extraction Coal Pile (Option A) Runoff Dam Seepage Attachment C —Process Flow Diagram Duke Energy Progress LLC Evaporation Post plant shutdown (starting Nov 2019 to Jan 2020) (Option A) French Broad Public Water River Supply Make-up Intake O Service Low Volume Water Structure Water Waste Sources Potable E N and PFSettling Zone Sanitary Systems Linea Public Sewer Retention D System (MSD) Pond Juleian Diesel Fire Fire Protection O EE Pump System Power Block K Industrial Storm U Water Onsite GG French Broad Coal Pile Runoff J Physical/Chemical Secondary River (temporary until WTS Settling Basin removal) Outfall 001 : ` BB I Contact SW and Evaporation < 1964 Ash Pond Interstitial water FF ---------------------------------------------------------------------------- Segregated clean SW (potentially) -------------� Attachment C — Process Flow Diagram Duke Energy Progress, LLC H Groundwater Extraction Asheville Steam Electric Plant Dam Seepage Buncombe County, September 2017 Post plant shutdown (starting Nov 2019 to Jan 2020) (Option B) French Broad Public Water River Supply Make-up Intake O Service Low Volume Water Structure Water Waste Sources Potable E Settling N and Zone Sanitary Systems C Lined CC Public Sewer Public Sewer Retention D System (MSD) Pond System (MSD) Lake Diesel Fire Fire Protection Q Jul an Pump System Power Block K Industrial Storm U Water Onsite DD Coal Pile Runoff J 30 PhysicaW-rSemical Secondary (temporary until Settling Basin removal) BB i Contact SW and i' Interstitial water Evaporation 1964 Ash Pond FF ------------------------------------------------------------------ -- Segregated clean SW (potentially) -------- H Groundwater Extraction Dam Seepage French Broad River Outfall 001 Attachment D - Flow, Sources of Pollution, and Treatment Technologies Duke Energy Progress, Inc. Asheville Steam Electric Plant — NPDES Permit Number NC0000396 Attachment D - Current Form 2C - Item II -A Flow, Sources of Pollution, and Treatment Technologies Stream Name Average Flow Comments A Ash Pond/Rim Ditch Discharge 3.52 MGD Outfall 001 B Intake to Once -through Cooling & Circulating Water to Heat Exchangers 255.1 MGD C Plant Potable and Sanitary Uses 0.002 MGD From POTW D Makeup to Lake from River 2.68 MGD 2009 Average E Low Volume Wastes • Ash Hopper Seals • Sandbed Filter Backwash • Boiler Blowdown • Truck Wash • Water purification process waste streams 0.05 MGD 2600 Gal/event 0.006 MGD Variable variable Rare Usage Startup - Estimated F Circulating Water from Heat Exchangers 19.3 MGD Estimated G Ash Sluice Water 3.03 MGD Estimated H Dam Seepage — 0.09 MGD Calculated I City Water Supply to Boiler Makeup 0 MGD Rare Usage J Coal Pile Runoff 0.01 MGD Based on Average Annual Rainfall of 47" and 50 % Runoff K Storm Water 0.07 MGD Estimated L Chemical Metal Cleaning Wastes 0 - 90,000 Gallons (0 gallons anticipated) Normal Practice is Evaporation M Water From Combustion Turbine Facility Operation (Blade wash activities) 0 - 0.02 MGD Intermittent N From Lake to Intake 256.59 MGD Estimated O Intake to Service Water 0.05 MGD Estimated Q Fire Protection Water 0.010 MGD Estimated R Air Preheater Cleaning 10,000 gallons/event Estimated S Discharge to Lake Julian 255.1 MGD T Emergency Fire Protection Water 0 Used for fire fighting Outfall 002 -Calculated U Diesel Fire Pump to Lake Julian 0.128 MG/week Estimate - pump testing V Flue Gas Desulfurization Blowdown 0.086 MGD Calculated X Intake to FGD system 01.08 MGD Y Chloride Dilution Water Lake water 0.35 MGD z FGD treatment system 0.376 MGD Outfall 005 AA Makeup water supply 22 Million gallons/year Calculated Attachment D - form 2C - Item IIA Flows, Sources of Pollution, and Treatment Technologies Duke Energy Progress , Inc. Asheville Steam Electric Plant Buncombe County October 2017 Page 2of 2 Duke Energy Progress, Inc. Asheville Steam Electric Plant — NPDES Permit Number NC0000396 Attachment D - Post Closure Option A Form 2C - Item II -A Flow, Sources of Pollution, and Treatment Technologies Stream Name Average Flow Comments C Plant Potable and Sanitary Uses 0.002 MGD From POTW D Makeup to Lake from River 2.68 MGD 2009 Average E Low Volume Wastes • Ash Hopper Seals • Sandbed Filter Backwash • Boiler Blowdown • Truck Wash • Water purification process waste streams 0.05 MGD 2600 Gal/event 0.006 MGD Variable variable Rare Usage Startup - Estimated H Dam Seepage 0.09 MGD Calculated J Coal Pile Runoff 0.01 MGD Based on Average Annual Rainfall of 47" and 50 % Runoff K Storm Water 0.07 MGD Estimated N From Lake to Intake 256.59 MGD Estimated O Intake to Service Water 0.05 MGD Estimated Q Fire Protection Water 0.010 MGD Estimated U Diesel Fire Pump to Lake Julian 0.128 MG/week Estimate - pump testing BB Contact SW and Interstitial Water 0.360 - 0.532 Estimated DD Onsite Physical/Chemical WTS 0.360 - 0.532 Estimated EE Lined Retention Pond 0.653 Estimated FF Segregated Clean SW 0.0-0.172 Estimated ILI GG Combined Onsite WTS 1.02-1.19 Estimated Attachment D - form 2C - Item IIA Flows, Sources of Pollution, and Treatment Technologies Duke Energy Progress , Inc. Asheville Steam Electric Plant Buncombe County • Duke Energy Progress, Inc. Asheville Steam Electric Plant — NPDES Permit Number NC0000396 Attachment D - Post Closure Option B Form 2C - Item II -A Flow, Sources of Pollution, and Treatment Technologies Stream Name Average Flow Comments C Plant Potable and Sanitary Uses 0.002 MGD From POTW D Makeup to Lake from River 2.68 MGD 2009 Average E Low Volume Wastes • Ash Hopper Seals • Sandbed Filter Backwash • Boiler Blowdown • Truck Wash • Water purification process waste streams 0.05 MGD 2600 Gal/event 0.006 MGD Variable variable Rare Usage Startup - Estimated H Dam ,Seepage — 0.09 MGD Calculated J Coal Pile Runoff 0.01 MGD Based on Average Annual Rainfall of 47" and 50 % Runoff K Storm Water 0.07 MGD Estimated N From Lake to Intake 256.59 MGD Estimated O Intake to Service Water 0.05 MGD Estimated Q Fire Protection Water 0.010 MGD Estimated U Diesel Fire Pump to Lake Julian 0.128 MG/week Estimate - pump testing BB Contact SW and Interstitial Water 0.360 - 0.532 Estimated DD Onsite Physical/Chemical WTS 0.360 - 0.532 Estimated E�E] FF Segregated Clean SW 0.0-0.172 Estimated Attachment D- form 2C - Item IIA Flows, Sources of Pollution, and Treatment Technologies Duke Energy Progress , Inc. Asheville Steam Electric Plant Buncombe County October 2017 Page 2of 2