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Home My WebLink AboutNC0024406_Draft Permit_20190903 51'ATFq� n, ROY COOPER Governor v ;, MICHAEL S. REGAN ,w Secretory \$=auv�,;,- LINDA CULPEPPER NORTH CAROLINA Director Environmental Quality September 3,2019 Mr. Paul Draovitch,Senior Vice President Environmental,Health and Safety Duke Energy Progress,LLC Mail Code EC13K P.O. Box 1006 Charlotte,North Carolina 28201-1006 Subject: Draft NPDES Permit Modification Permit NC0024406 Belews Creek Steam Station Stokes County Facility Class I Dear Mr. Draovitch: The Division has received your request to allow decanting via Outfall 006A.The request has been granted. Enclosed with this letter is 2 pages that include necessary modifications. Please review these pages to ensure thorough understanding of the conditions and requirements they contain. The draft 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. Please provide any comments you have regarding the draft permit to this office ce by October 4, 2019. At this time, the Division is also publishing a notice in the newspapers of general circulation in Stokes County,inviting public comment on the Draft Modification. Following the 30- day comment period,we will review all pertinent comments received and take appropriate action on the permit modification. EQ CMPIMErrhonmen. North Carolina Department of Environmental Quality I Division of Water Resources 512 North Salisbury Street 11617Mail Service Center I Raleigh.North Carolina 27699-1617 919.707.3601 If you have any questions about the NPDES permit process,please contact me at the following e-mail address: sergei.chernikov( ncdenr.gov,or telephone number: 919-707-3606. Sincerely, Sergei Chernikov,Ph.D. Environmental Engineer III Complex NPDES Permitting Unit cc: Central Files NPDES Files EPA Region IV(e-copy) Winston-Salem Regional Office/Water Quality(e-copy) Winston-Salem Regional Office/PWS (e-copy) WSS/Aquatic Toxicology Unit(e-copy) Page 2 of 2 Permit NC0024406 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: Ash Basin discharge consisting of waste streams from the power house and yard holding sumps, ash contact water, chemical holding pond, coal yard sumps, stormwater, treated domestic wastewater, remediated groundwater, coal pile collection basins (collecting contact stormwater from coal piles), emergency release of anhydrous ammonia, release of ammonia during quarterly testing, seepage from coal ash pond, emergency overflows from the existing effluent channels, emergency overflow from the retention basin, and treated FGD wastewater from internal Outfall 002. This outfall discharges to Unnamed Tributary (UT) to Dan River. • Internal Outfall 002: FGD wastewater (discharging to ash pond). • Outfall 003A/006. Upon completion of construction, 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. Upon completion of construction all waste streams previously discharged to ash basin will be re-routed to the new retention basin. During the transition period, wastewater from the ash pond can also be discharged from 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. - 36016'51.604"; 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. • Internal Outfall 009. Domestic wastewater plant. The wastewater from this outfall discharges to UT to Dan River via Outfall 003 or to Dan River via new Outfall 006. Page 2 of 23 Permit NC0024406 A. (4.) EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS (Internal Outfall 006A - 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 Daily Measurement Sample Type Sample Location Average Maximum Frequency Flow 2.0 MGD11 Daily Pump logs or Effluent estimate Oil and Grease1 15.0 mg/L 20.0 mg/L Weekly Grab Effluent Total Suspended Solids17 30.0 mg/L 50.0 mg/L Weekly Grab Effluent Total Arsenic Weekly Grab Effluent Chlorides, mg/L Weekly Grab Effluent Total Iron,mg/L1° 1.0 mg/L 1.0 mg/L Weekly Grab Effluent Total Copper 211.3 pg/L 231.4 pg/L Weekly Grab Effluent Total Selenium 134.0 pg/L 1,237 pg/L Weekly Grab Effluent Total Molybdenum 4,289 pg/L 4,289 pg/L Weekly Grab Effluent Total Aluminum 174.2 mg/L 174.2 mg/L Weekly Grab Effluent Fluoride, mg/L Weekly Grab Effluent Chromium VI, pg/L Weekly Grab Effluent Total Cadmium, pg/L Weekly Grab Effluent Total Zinc, pg/L Weekly Grab Effluent Total Nickel, pg/L Weekly Grab Effluent Total Dissolved Solids, mg/L Weekly Grab Effluent Total Phosphorus,mg/L Monthly Grab Effluent Total Nitrogen(NO2+NO3+TKN),mg/L Monthly Grab Effluent Chronic Toxicity2 Monthly Grab Effluent pH3,8 Weekly Grab Effluent Bromides, mg/L Weekly Grab Effluent Total Lead 30.5 pg/L 654.6 pg/L Weekly Grab Effluent Total Thallium, pg/L Weekly Grab Effluent Total Barium,mg/L Weekly Grab Effluent Sulfates,mg/L Weekly Grab Effluent Total Antimony, Ng/L Weekly Grab Effluent Total Mercury4,ng/L Weekly Grab Effluent Turbidity6, NTU Weekly Grab Effluent Total Hardness,mg/L Weekly Grab Effluent Ammonia9 1.0 mg/L 5.0 mg/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