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Home My WebLink AboutNC0024406_Modification_20191023ROY COOPER Governor MICHAEL S. REGAN Secretary LINDA CULPEPPER Director Mr. Paul Draovitch, Senior Vice President Environmental, Health and Safety Duke Energy Carolinas, LLC Mail Code EC13K P.O. Box 1006 Charlotte, North Carolina 28201-1006 Dear Mr. Draovitch: NORTH CAROLINA Envlronmento/ Quality October 22, 2019 Subject: Permit Modification Permit NCO024406 Belews Creek Steam Station Stokes County Facility Class I The Division has received your request to allow decanting via Outfall 006A. The request has been granted. This modification becomes effective immediately. Enclosed with this letter are 2 pages that include necessary changes. Please replace the existing permit pages with the modified pages. The permit modification contains the following significant changes from your current permit: • Internal Outfall 006A now allows discharge of the wastewater from the decanting procedure. • The Water Quality Based Effluent Limits (Monthly Average and Daily Maximum) for Total Lead have been reduced (Internal Outfall 006A) due to the increase in the flow through this Outfall. The projected decanting flow is 5.5 MGD. No other changes have been made. This permit modification is issued pursuant to the requirements of North Carolina General Statute 143-215.1 and the Memorandum of Agreement between North Carolina and the U.S. Environmental Protection Agency. Please take notice that this permit is not transferable. Part I1, EA. addresses the requirements to be followed in case of change in ownership or control of this discharge. If you have any questions or need additional information, please contact Sergei Chemikov, telephone number (919) 707-3606 or email: sergei.chemikov@ncdenr.gov. Sincerely, Linda Culpepper, Director 0( Division of Water Resources cc: Central Files NPDES Files Winston-Salem Regional Office/Water Quality WSS/Aquatic Toxicology Unit (e-copy) EPA Region N (e-copy) North CaroMa Departnrnt W Emirorcrcnl.Y Quenty- Olrislan d water Resources 512 North Salbhuq Sued 116f7Nail Sersxe Center I Raleigh Narth Caroline 27bW1611 Permit NCO024406 SUPPLEMENT TO PERMIT COVER SHEET All previous NPDES Permits issued to this facility, whether for operation or discharge are hereby revoked. As of this permit issuance, any previously issued permit bearing this number is no longer effective. Therefore, the exclusive authority to operate and discharge from this facility arises under the permit conditions, requirements, terms, and provisions included herein. Duke Energy Carolinas, LLC is hereby authorized to: 1. Continue to discharge: • Outfall 001: once through cooling water consisting of intake screen backwash, recirculating cooling water, station equipment cooling water and once -through cooling water. This outfall discharges to Belews Lake. • Outfall 003: Stormwater and remediated groundwater. This outfall discharges to Unnamed Tributary (UT) to Dan River. • Internal Outfall 002: FGD wastewater (discharging to line retention basin). • Outfall 003A/006. Discharge from the new Lined Retention Basin. Basin will accept wastes from holding basin, ash contact water, various sumps, coal pile runoff, stormwater runoff, cooling tower blowdown, FGD wastewater, and various low volume wastes such as boiler blowdown, oily waste treatment, wastes/backwash from the water treatment processes, coal pile collection basins (collecting contact stormwater from coal piles), plant area wash down water, cooling tower blowdown, equipment heat exchanger water, remediated groundwater, emergency overflow (rain in excess of designed storm event), toe drain (potential discharge to outfall 006 only), emergency release of anhydrous ammonia, release of ammonia during quarterly testing, and treated domestic wastewater. Outfall 003A discharges to UT to Dan River via the Outfall 003. Construction of new Outfall 006 has been completed. Outfall 006 will discharge to Dan River. This Outfall will be used for decanting and dewatering of the ash basin. Outfall 005. This is a former stormwater outfall SW002, consisting of once through non -contact chiller water and stormwater. This outfall discharges to Belews Lake. Internal Outfall 006A. This is a temporary internal outfall for decanting and dewatering of the ash basin, it will discharge through new Outfall 006. Outfall 007 (lat. - 3601651.604"; long. 80003'52.995"). This is an emergency spillway for South Coal Basin. This outfall discharges to Belews Lake. The spillway is designed for a flood greater than 100-year event. Sampling of this spillway is waived due to unsafe conditions associated with sampling during overflow events. Page 1 of Permit NC0024406 A. (4.) EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS (Internal 0utfall 0O6A - dewatering/decanting) [15A NCAC 02B .0400 et seq., 02B .0500 et seq.) During the period beginning on the commencement of decanting and lasting until expiration of the permit, the Permittee is authorized to discharge from Outfall 006A Ash settling basin (Dewatering — removing the interstitial water. Decanting- decanting the free water above the settled ash layer). Such discharges shall be limited and monitored5 by the Permittee as specified below: PARAMETER LIMITS MONITORING REQUIREMENTS Monthly Average Daily Measurement Sample Type Maximum Frequency Sample Location Flow 2.0 MGDfl Daily Pump logs or estimate Effluent Oil and Grease' 15.0 m /L 20.0 m /L Weekly Grab Effluent Total Suspended Solids'•r 30.0 m /L 50.0 m /L Weekly Grab Effluent Total Arsenic Weekly Grab Effluent Chlorides, m /L Weekly Grab Effluent Total Iron, m /L10 1.0 m /L 1.0 m /L Weekly Grab Effluent Total Copper 211.3 /L 231.4 /L Weekly Grab Effluent Total Selenium 134.0 /L 1,237 /L Weekly Grab Effluent Total Molybdenum 4,289 ljqlL 4,289 /L Weekly Grab Effluent Total Aluminum 174.2 m /L 174.2 m /L Weekly Grab Effluent Fluoride, m /L Weekly Grab Effluent Chromium VI, /L Weekly Grab Effluent Total Cadmium, /L Weekly Grab Effluent Total Zinc, /L Weekly Grab Effluent Total Nickel, /L Weekly Grab Effluent Total Dissolved Solids, m /L Weekly Grab Effluent Total Phosphorus, m /L Monthly Grab Effluent Total Nitrogen NO2 + NO3 + TKN , m /L Monthly Grab Effluent Chronic Toxicit 2 Monthly Grab Effluent H3,e Weekly Grab Effluent Bromides, m /L Weekly Grab Effluent Total Lead 30.5 /L 654.6 /L Weekly Grab Effluent Total Thallium, /L Weekly Grab Effluent Total Barium, m /L Weekly Grab Effluent Sulfates, m /L Weekly Grab Effluent Total Antimony, /L Weekly Grab Effluent Total Mercu , n /L Weekl Grab Effluent Turbidity6, NTU Weekl Grab Effluent Total Hardness, m /L Weekly Grab Effluent Ammonia9 1.0 m /L 5.0 m /L Variable Grab Effluent Notes: 1. Monitoring for TSS, oil and grease and all toxicants shall be performed concurrently with the Chronic Toxicity test. 2. Whole Effluent Toxicity shall be monitored by chronic toxicity (Ceriodaphnia) P/F at 3.7%. See Condition A. (14.) for details. 3. The pH shall not be less than 6.0 standard units nor greater than 9.0 standard units. 4. The facility shall employ method 1631E. 5. Please See Special Condition A. (23.). 6. The discharge from this facility shall not cause turbidity in the receiving stream to exceed 50 NTU. If the instream turbidity exceeds 50 NTU due to natural background conditions, the discharge cannot cause turbidity to increase in the receiving stream. Therefore, if the effluent measurement exceeds 50 NTU, the Permittee shall sample upstream and downstream turbidity in the receiving Page 8 of 23