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HomeMy WebLinkAboutNC0004961_Draft Permit_20150306NCDENR North Carolina Department of Environment and Natural Resources Pat McCrory Governor Mr Harry Sidens, 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. Sideris- Donald R. van der Vaart Secretary March 6, 2015 Subject. Draft NPDES Permit Permit NC0004961 Riverbend Steam Station Gaston County Facility Class I Enclosed with this letter is a copy of the draft permit for your facility Please review the draft very carefully to ensure thorough understanding of the conditions and requirements it contains The draft permit contains the following significant changes from your current permit: • Monitoring requirements for Outfall 001 were adjusted due to the discontinuation of once - through cooling water discharges. • The Ash Pond Closure Special Condition was updated (Please see A (15 )). • The Seep Outfall 010 (Please see A. (5.)) and Seep Pollutant Analysis Special Condition (Please see A. (17 )) were added to the permit. • The Appendix A and Appendix B were added to the permit • A separate effluent page for the dewatering of the ash ponds (Outfall 002) was added to the permit (Please see Special Condition A (3 )). • The Boiler Cleaning Waste Special Condition was eliminated due to the discontinuation of the power generation • The Section 316(a) of CWA Thermal Variance Special Condition was eliminated due to the discontinuation of the power generation. • The Section 316(b) of CWA Special Condition was eliminated due to the discontinuation of the power generation. • The turbidity limit was added to the permit to meet the state turbidity standard per 15A NCAC 2B .0211(3) (k) (Outfall 002) • The Technology Based Effluent Limits for Total Arsenic, Total Mercury, Total Selenium, and Nitrate/mtnte as N were added to the permit and are based on the requirements of 40 CFR 125.3(a) , 40 CFR 122 44(a)(1); 40 CFR 125.3(c) and (d) (Outfall 002 and Outfall 010) • The Interim Technology Based Effluent Limits (Outfall 002) for Total Arsenic, Total Selenium, and Nitrate/nitrate as N were added to the permit and are based on the requirements of 40 CFR 125.3(a) , 40 CFR 122 44(a)(1), 125.3(c) and (d) 1617 Mall Service Center, Raleigh, North Carolina 27699-1617 Phone 919-807-63001 Internet www ncwaterquality org An Equal Opportunity 1 Affirmative Action Employer— Made in part by recycled paper • Proposed federal regulations require electronic submittal of all discharge monitoring reports (DMRs) and specify that, if a state does not establish a system to receive such submittals, then permittees must submit DMRs electronically to the Environmental Protection Agency (EPA) The Division anticipates that these regulations will be adopted and is beginning implementation. The requirement to begin reporting discharge monitoring data electronically using the NC DWR's Electronic Discharge Monitoring Report (eDMR) internet application has been added to the permit. (Please see Special Condition A. (18.)) The Applicable State Law Special Condition was added to the permit to meet the requirements of Senate Bill 729 (Coal Ash Management Act, Please see Special Condition A (19.)). The Outfall 011 (former Stormwater Outfall 1) was added to the permit (Please see A. (20.)). Please provide any comments you have regarding the draft permit to this office by April 6, 2015. At this time, the Division is also publishing a notice in the newspapers of general circulation in Gaston County, inviting public comment on the draft permit. Following the 30 -day comment period, we will review all pertinent comments received and take appropriate action on the permit renewal. If you have any questions about the NPDES permit process, please contact me at the following e-mail address sergei chernikov(a,ncdenr.gov, or telephone number 919-807-6386. Sincerely, Sergei Chernikov, Ph.D G/ Environmental Engineer II Complex NPDES Permuting Unit cc Central Files NPDES Files EPA Region IV Mooresville Regional Office / Water Quality (e -copy) Mooresville Regional Office / Public Water Supply Regional Engineer (e -copy) WSS/Aquatic Toxicology Unit (e -copy) 1617 Mall Service Center, Raleigh, North Carolina 27699-1617 Phone. 919-807-63031 Internet www rimaterquallty org An Equal Opportunity 1 AffirmatNe Acton Employer — Made in part by recycled paper Permit NC0004961 STATE OF NORTH CAROLINA DEPARTMENT OF ENVIRONMENT AND NATURAL RESOURCES DIVISION OF WATER RESOURCES Draft PERMIT TO DISCHARGE WASTEWATER UNDER THE NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM In compliance with the provision of North Carolina General Statute 143-215 1, other lawful standards and regulations promulgated and adopted by the North Carolina Environmental Management Commission, and the Federal Water Pollution Control Act, as amended, Duke Energy Carolinas, LLC is hereby authorized to discharge wastewater from a facility located at the Riverbend Steam Station Mount Holly Gaston County to receiving waters designated as the Catawba River in the Catawba River Basin in accordance with effluent limitations, monitoring requirements, and other applicable conditions set forth in Parts I, II, III and IV hereof. This permit shall become effective This permit and authorization to discharge shall expire at midnight on February 28, 2020. Signed this day DRAFT S. Jay Zimmerman, Director Division of Water Resources By Authority of the Environmental Management Commission Page 1 of 15 Permit NC0004961 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: Once through cooling water (outfall 00 1) consisting of intake screen backwash and water from the plant chiller system, turbine lube oil coolers, condensate coolers, main turbine steam condensers and the intake tunnel dewatering sump • Ash basin discharge (outfall 002) consisting of induced draft fan and preheater bearing cooling water, stormwater from roof drains and paving, treated groundwater, track hopper sump (groundwater), coal pile runoff, laboratory drain and chemical makeup tanks and drums rinsate wastes, general plant/ trailer sanitary wastewater, turbine and boiler rooms sumps, vehicle rinse water, and stormwater from pond areas, upgradient watershed, and miscellaneous stormwater flows. Yard sump overflow (outfall 002A). 12 potentially contaminated groundwater seeps (outfall 010). Wastewater, stormwater and groundwater (outfall 011). From a facility located at Riverbend Steam Station, Mount Holly in Gaston County, and 2. Discharge wastewater from said treatment works at the location specified on the attached map into the Catawba River, which is classified WS -IV and B -CA waters in the Catawba River Basin. Page 2 of 15 Permit NC0004961 Part I A. (1.) EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS (Outfall 001) [15A NCAC 02B 0400 et seq , 02B 0500 et seq ] During the period beginning on the effective date of this permit and lasting until expiration, the Permittee is authorized to discharge once -through cooling water and intake screen backwash from outfall 001 Such discharges shall be limited and monitored3 by the Permittee as specified below. EFFLUENT CHARACTERISTICS LIMITS MONITORING REQUIREMENTS MonthlyDaily Average Maximum Measurement Fre uency Sample Type Sample Location' Flow Monthly Pump Logs Influent or Effluent Temperature (OF) Monthly Grab Effluent Temperature (oF)2 89 6 (32oC) Monthly Grab Downstream Notes 1 Downstream sampling point downstream at Mountain Island Lake If samples are collected below the water surface, the Permittee will record the sample depth on the DMR form 2 The ambient temperature shall not exceed 89 60F (32 0°C) and is defined as the daily average downstream water temperature. When the Riverbend Station effluent temperature is recorded below 89.60F (32 0°C), as a daily average, then monitoring and reporting of the downstream water temperature is not required In cases where the Permittee experiences equipment problems and is unable to obtain daily temperatures from the existing temperature monitoring system, the temperature monitoring must be reestablished within five working days 3 No later than 270 days from the effective date of this permit, begin submitting discharge monitoring reports electronically using NC DWR's eDMR application system See Special Condition A. (18 ). Chlorination of the once through condenser cooling water, discharged through outfall 001, is not allowed under this permit. Should Duke Energy wish to chlorinate its condenser cooling water, a permit modification must be requested and received prior to commencing chlorination. There shall be no discharge of floating solids or visible foam in other than trace amounts Page 3 of 15 Permit NC000496 T A. (2.) EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS (Outfall 002) [15A NCAC 02B.0400 et seq , 02B 0500 et seq ] During the period beginning on the effective date of this permit and lasting until expiration, the Permittee is authorized to discharge from outfall 002 — Ash Pond Discharge Such discharges shall be limited and monitored? by the Permittee as specified below EFFLUENT CHARACTERISTICS LIMITS MONITORING REQUIREMENTS Monthly v Daily Measurement Sample Type Sample Location Average Maximum Frequency Flow Weekly Pump logs or estimate Influent or Effluent Total Suspended Solids' 23 0 mg/L 75 0 mg/L Monthly Grab Effluent Oil and Grease 110 mg/L 15 0 mg/L Annually Grab Effluent Total Copper2 10 mg/L 10 mg/L Quarterly Grab Effluent Total Iron2 10 mg/L 10 mg/L Quarterly Grab Effluent Total Arsenic 52 5 tig/L 72 5 dig/L Quarterly Grab Effluent Total Selenium 68 0 fig/L 127 5 Ng/L Quarterly Grab Effluent Nitrate/nitrite as N 0 65 mg/L 0 85 mg/L Quarterly Grab Effluent Total Arsenic 10 5pg/L8 14 5 pg/L8 Quarterly Grab Effluent Total Selenium 13 6 pg/L8 25 5 Ng/L8 Quarterly Grab Effluent Total Mercury 47 0 ng/L6 47 0 ng/L6 Quarterly Grab Effluent Nitrate/nitrite as N 013 mg/L8 017 mg/L8 Quarterly Grab Effluent Total Phosphorus Semi-annually Grab Effluent Total Nitrogen (NO2 + NO3 + TKN) Semi-annually Grab Effluent pH3 Monthly Grab Effluent Chronic Toxicity4 Quarterly Grab Effluent Turbidity5 Monthly Grab Effluent Notes - 1 Monthly average of 43 mg/ L is permitted provided that the Permittee can satisfactorily demonstrate that the difference between 23 mg/L and 43 mg/L is a result of the concentration of total suspended solids in the intake water. 2. The limits for total copper and total iron only apply during a chemical metals cleaning. 3. The pH shall not be less than 6 0 standard units nor greater than 9.0 standard units 4 Whole Effluent Toxicity shall be monitored by chronic toxicity (Ceriodaphnia) P/F at 10%. Tests shall be conducted in January, April, July and October (see Part A (6.) for details). 5 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 NTU - Nephelometric Turbidity Unit. 6 The facility shall use EPA method 1631E 7 No later than 270 days from the effective date of this permit, begin submitting discharge monitoring reports electronically using NC DWR's eDMR application system. See Special Condition A (18 ). 8 Facility is allowed 4.5 years from the effective date of the permit to comply with the TBELs This time period is provided in order for the facility to budget, design, and construct the treatment system Permit might be re -opened to implement the final EPA Effluent Guidelines and more stringent limits might be added. The metal cleaning waste, coal pile runoff, ash transport water, domestic wastewater, and low volume waste shall be discharged into the ash settling pond. No chemicals, cleaners, or other additives may be present in the vehicle wash water to be discharged from this outfall. There shall be no discharge of floating solids or visible foam in other than trace amounts. Page 4 of 15 Permit NC0004961 A. (3.) EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS (Outfall 002) [15A NCAC 02B 0400 et seq , 02B 0500 et seq ] During the period beginning on the effective date of this permit and lasting until expiration, the Permittee is authorized to discharge from outfall 002 - Ash Pond Discharge (Dewatering) Such discharges shall be limited and monitored' by the Permittee as specified below - EFFLUENT CHARACTERISTICS LIMITS MONITORING REQUIREMENTS Monthly Daily Measurement Sample Type Sample Location Average Maximum Frequency Flow Weekly Pump logs or estimate Influent or Effluent Total Suspended Solids' 23 0 mg/L 75 0 mg/L Monthly Grab Effluent Oil and Grease 110 m /L 15 0 mg/L Annually Grab Effluent Total Copper2 10 mg/L 10 mg/L Quarterly Grab Effluent Total Iron2 10 mg/L 10 mg/L Quarterly Grab Effluent Total Arsenic 10 5 pg/L 14 5 Ng/L Quarterly Grab Effluent Total Selenium 13 6 Ng/L 25 5 pg/L Quarterly Grab Effluent Total Aluminum 318 mg/L 318 mg/L Quarterly Grab Effluent Total Mercury 47 0 ng/L6 47 0 ng/Ls Quarterly Grab Effluent Nitrate/nitrate as N 013 mg/L 017 mg/L Quarterly Grab Effluent Total Phosphorus Semi-annually Grab Effluent Total Nitrogen (NO2 + NO3 + TKN) Semi-annually Grab Effluent pH3 Monthly Grab Effluent Chronic ToxiCity4 Quarterly Grab Effluent Turbidity5 Monthly Grab Effluent Notes: 1 Monthly average of 43 mg/ L is permitted provided that the Permittee can satisfactorily demonstrate that the difference between 23 mg/L and 43 mg/L is a result of the concentration of total suspended solids in the intake water 2. The limits for total copper and total .iron only apply during a chemical metals cleaning 3. The pH shall not be less than 6.0 standard units nor greater than 9 0 standard units. 4. Whole Effluent Toxicity shall be monitored by chronic toxicity (Ceriodaphnia) P/F at 10% Tests shall be conducted in January, April, July and October (see Part A.(6.) for details). 5. The discharge from this facility shall not cause turbidity in the receiving stream to exceed 50 NTU If the instream turbidity exceeds 56 NTU due to natural background conditions, the discharge cannot cause turbidity to increase in the receiving stream. NTU - Nephelometric Turbidity Unit. 6. The facility shall use EPA method 1631E 7. No later than 270 days from the effective date of this permit, begin submitting discharge monitoring reports electronically using NC DWR's eDMR application system See Special Condition A (18.). The metal cleaning waste, coal pile runoff, ash transport water, domestic wastewater, and low volume waste shall be discharged into the ash settling pond. No chemicals, cleaners, or other additives may be present in the vehicle wash water to be discharged from this outfall. There shall be no discharge of floating solids or visible foam in other than trace amounts. Page 5 of 15 Permit NC0004961' A. (4.) EFFLUENT LIMITATIONS. AND MONITORING REQUIREMENTS (Outfall 002A) [15A NCAC 02B .0400 et seq , 02B .0500 et seq.] During the period beginning on the effective date of this permit and lasting until expiration, the Permittee is authorized to discharge from outfall 002A - Yard Sump Overflows Such discharges shall be limited and monrtored4 by the Permittee as specified below: EFFLUENT � CHARACTERISTICS LIMITS , MONITORING REQUIREMENTS Monthly Daily Average Maximum Measurement Sample Type Sample Location' Frequency Flow Episodic Estimate Effluent Total Suspended Solids2 23.0 mg/L 75 0 m /L Episodic Grab Effluent Oil and Grease2 110 mg/L 15 0 mg/L Episodic Grab Effluent Fecal Coliform Episodic Grab Effluent Total Copper3 10 mg/L 10 mg/L Episodic Grab Effluent Total Iron3 10 mg/L 10 mg/L Episodic Grab Effluent pH5 Episodic Grab Effluent Notes: 1. Effluent sampling shall be conducted at a point upstream of discharge to the receiving stream. 2. The monthly average limits for total suspended solids and oil and grease are applicable only if the overflow occurs for more than 24 hours 3. The limits for total copper and total iron only apply during a chemical metals cleaning 4. No later than 270 days from the effective date of this permit, begin submitting discharge monitoring reports electronically using NC DWR's eDMR application system. See Special Condition A. (18.). 5. The pH shall not be less than 6 0 standard units nor greater than 9.0 standard units. THERE SHALL BE NO DISCHARGE OF FLOATING SOLIDS OR VISIBLE FOAM IN OTHER THAN TRACE AMOUNTS ALL FLOWS SHALL BE REPORTED ON MONTHLY DMRS. SHOULD NO FLOW OCCUR DURING A GIVEN MONTH, THE WORDS "NO FLOW" SHOULD BE CLEARLY WRITEN ON THE FRONT OF THE DMR. EPISODIC SAMPLING IS REQUIRED PER OCCURRANCE WHEN SUMP OVERFLOWS OCCUR FOR LONGER THAN ONE HOUR. ALL SAMPLES SHALL BE OF A REPRESENTATIVE DISCHARGE. Page 6 of 15 Permit NC0004961 A. (5.) EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS (Outfall 010) [15A NCAC 02B 0400 et seq , 02B 0500 et seq.] During the period beginning on the effective date of this permit and lasting until expiration, the Permittee is authorized to discharge from Outfall 010 (combined seep outfall). Such discharges shall be limited and monitored' by the Permittee as specified below EFFLUENT CHARACTERISTICS DISCHARGE LIMITATIONS MONITORING REQUIREMENTS Monthly Average Weekly Average Daily Maximum Measurement Frequency2 Sample Type Sample Location Total Suspended Solids 30 0 mg/L 100 0 mg/L Monthly Grab Effluent Total Arsenic 10 5 pg/L4 14 5 pg/L4 Monthly Grab Effluent Total Mercury3 47 0 ng/L4 47 0 ng/L4 Monthly Grab Effluent Total Selenium 13 6 pg/L4 25 5 pg/L4 Monthly Grab Effluent Nitrate/nitrite as N 013 mg/L4 017 mg/L4 Monthly Grab Effluent Flow Monitor & Report Monthly Grab Effluent TDS Monitor & Report Monthly Grab Effluent Chlorides Monitor & Report Monthly Grab Effluent Fluoride Monitor & Report Monthly Grab Effluent Total Barium Monitor & Report Monthly Grab Effluent Total Iron Monitor & Report Monthly Grab Effluent Total Manganese Monitor & Report Monthly Grab Effluent Total Zinc Monitor & Report Monthly Grab Effluent Total Cadmium Monitor & Report Monthly Grab Effluent Total Chromium Monitor & Report Monthly Grab Effluent Total Copper Monitor & Report Monthly Grab Effluent Total Lead Monitor & Report Monthly Grab Effluent Total Nickel Monitor & Report Monthly Grab Effluent Temperature Monitor & Report Monthly Grab Effluent Specific Conductance Monitor & Report Monthly Grab Effluent pH Between 6 0 and 9 0 standard units Monthly Grab Effluent NOTES: 1. No later than 270 days from the effective date of this permit, begin submitting discharge monitoring reports electronically using NC DWR's eDMR application system See Special Condition A (18.) 2. After the first year, the monitoring frequency will be reduced to a semi-annual basis. 3 The facility shall use EPA method 1631E 4. The limits can be met by installation of the treatment system, re-routing the discharge to the existing treatment system, or discontinuing the discharge There shall be no discharge of floating solids or visible foam in other than trace amounts. Page 7 of 15 Permit NC000496I' A. (6.) CHRONIC TOXICITY PASS/FAIL PERMIT LIMIT (QUARTERLY) (Outfall 002) [15A NCAC 02B 0200 et seq.] The effluent discharge shall at no time exhibit observable inhibition of reproduction or significant mortality to Ceriodaphnia dubia at an effluent concentration of 2.7% The permit holder shall perform at a minimum,guarterlmonitoring using test procedures outlined in the "North Carolina Cenodaphnia Chronic Effluent Bioassay Procedure," Revised December 2010, or subsequent versions or "North Carolina Phase II Chronic Whole Effluent Toxicity Test Procedure" (Revised- December 2010) or subsequent versions The tests will be performed during the months of January, April, July, and October These months signify the first month of each three-month toxicity testing quarter assigned to the facility Effluent sampling for this testing must be obtained during representative effluent discharge and shall be performed at the NPDES permitted final effluent discharge below all treatment processes If the test procedure performed as the first test of any single quarter results in a failure or ChV below the permit limit, then multiple -concentration testing shall be performed at a minimum, in each of the two following months as described in "North Carolina Phase II Chronic Whole Effluent Toxicity Test Procedure" (Revised -December 2010) or subsequent versions. All toxicity testing results required as part of this permit condition will be entered on the Effluent Discharge Monitoring Form (MR -1) for the months in which tests were performed, using the _ parameter code TGP313 for the pass/fail results and THP313 for the Chronic Value Additionally, DWR Form AT -3 (original) is to be sent to the following address - Attention North Carolina Division of Water Resources Water Sciences Section/Aquatic Toxicology Branch 1621 Mail Service Center Raleigh, North Carolina 27699-1621 Completed Aquatic Toxicity Test Forms shall be filed with the Water Sciences Section no later than 30 days after the end of the reporting period for which the report is made. Test data shall be complete, accurate, include all supporting chemical/ physical measurements and all concentration/ response data, and be certified by laboratory supervisor and ORC or approved designate signature Total residual chlorine of the effluent toxicity sample must be measured and reported if chlorine is employed for disinfection of the waste stream. Should there be no discharge of flow from the facility during a month in which toxicity monitoring is required, the permittee will complete the information located at the top of the aquatic toxicity (AT) test form indicating the facility name, permit number, pipe number, county, and the month/year of the report with the notation of "No Flow" in the comment area of the form The report shall be submitted to the Water Sciences Section at the address cited above. Should the permittee fail to monitor during a month in which toxicity monitoring is required, monitoring will be required during the following month. Assessment of toxicity compliance is based on the toxicity testing quarter, which is the three month time interval that begins on the first day of the month in which toxicity testing is required by this permit and continues until the final day of the third month. Should any test data from this monitoring requirement or tests performed by the North Carolina Division of Water Resources indicate potential impacts to the receiving stream, this permit may be re -opened and modified to include alternate monitor=ng requirements or limits. NOTE Failure to achieve test conditions as specified in the cited document, such as minimum control organism survival, minimum control organism reproduction, and appropriate environmental Page 8of15 Permit NC0004961 controls, shall constitute an invalid test and will require immediate follow-up testing to be completed no later than the last day of the month following the month of the initial monitoring A. (7.) BIOCIDE CONDITION The permittee shall not use any biocides except those approved in conjunction with the permit application The permittee shall notify the Director in writing not later than ninety (90) days prior to instituting use of any additional biocide used in cooling systems which may be toxic to aquatic life other than those previously reported to the Division of Water Resources Such notification shall include completion of Biocide Worksheet From 101 and a map locating the discharge point and receiving stream Completion of a Biocide Worksheet 101 is not necessary for the introduction of a new biocide into an outfall currently being tested for toxicity A. (8.) SPECIAL CONDITIONS The following special conditions are applicable to all outfalls regulated by NC0004961 • There shall be no discharge of polychlorinated biphenyl compounds • The Permittee shall check the diked areas for leaks by a visual inspection and shall report any leakage detected • Nothing contained in this permit shall be construed as a waiver by the Permittee or any right to a hearing it may have pursuant to State or Federal laws or regulations • Discharge of any product registered under the Federal Insecticide, Fungicide, and Rodenticide Act to any waste stream which may ultimately be released to lakes, rivers, streams or other waters of the United States is prohibited unless specifically authorized elsewhere in this permit Discharge of chlorine from the use of chlorine gas, sodium hypochlorite, or other similar chlorination compounds for disinfection in the plant potable and service water systems and in sewage treatment is authorized Use of restricted use pesticides for lake management purposes by applicators licensed by the N C Pesticide Board is allowed • The Permittee shall report all visible discharges of floating materials, such as an oil sheen, to the Director when submitting DMRs A. (9.) PERMIT TERMS The following are applicable to all outfalls regulated by NC0004961 • The term "low volume waste sources" means, taken collectively as if from one source, wastewater from all sources except those for which specific limitations are otherwise established in this part Low volume wastewater sources include, but are not limited to wastewater from wet scrubber air pollution control systems, ion exchange water treatment system, water treatment evaporator blowdown, laboratory and sampling streams, boiler blowdown, floor drains, cooling tower basin cleaning wastes, and recirculating service water systems. Sanitary and air conditioning wastes are not included. • The term "metal cleaning waste" means any wastewater resulting from cleaning (with or without chemical cleaning compounds) any metal process equipment including, but not limited to, boiler tube cleaning, boiler fireside cleaning, and air preheater cleaning Chemical metal cleaning will be conducted according to Duke Energy approved equivalency demonstration • It has been determined from information submitted that the plans and procedures in place at Riverbend Steam Station are equivalent to that of a BMP A. (10.) ASH SETTLING BASIN Beginning on the effective date of this permit and lasting until expiration, there shall be no discharge of plant wastewater to the ash pond unless the Permittee provides and maintains at all times a minimum free water volume (between the top of the sediment level and the minimum discharge elevation) equivalent to the sum of the maximum 24-hour plant discharges plus all direct rainfall and all runoff flows to the pond resulting from a 10 -year, 24-hour rainfall event, when using a runoff coefficient of 1 0. During the term of the permit, the Permittee shall remove settled material from the ponds or otherwise enlarge the available storage capacities in order to maintain the required Page 9 of 15 Permit NC000496 Y minimum volumes at all times The Permittee shall determine and report to the permit issuing authority the following on an annual basis 1) the actual free water volume of the ash pond, 2) physical measurements of the dimensions of the free water volume in sufficient detail to allow validation of the calculated volume, and 3) a certification that the required volume is available with adequate safety factor to include all solids expected to be deposited in the pond for the following year. Present information indicates a needed volume of 86.2 acre-feet in addition to solids that will be deposited to the ash pond, any change to plant operations affecting such certification shall be reported to the Director within five days NOTE In the event that adequate volume has been certified to exist for the term of the permit, periodic certification is not needed A. (11.) GROUNDWATER MONITORING WELL CONSTRUCTION AND SAMPLING The permittee shall conduct groundwater monitoring to determine the compliance of this NPDES permitted facility with the current groundwater Standards found under 15A NCAC 2L 0200 The monitoring shall be conducted in accordance with the Sampling Plan approved by the Division. A.(12.) STRUCTURAL INTEGRITY INSPECTIONS OF ASH POND DAM The facility shall meet the dam design and dam safety requirements per 15A NCAC 2K. A.(13.) FISH TISSUE MONITORING NEAR ASH POND DISCHARGE The facility shall conduct fish tissue monitoring once during the permit term and submit the results with the NPDES permit renewal application The objective of the monitoring is to evaluate potential uptake of pollutants by fish tissue near the Ash Pond discharge. The parameters analyzed in fish tissue shall be arsenic, selenium, and mercury The monitoring shall be conducted in accordance with the Sampling Plan approved by the Division. A.(14.) INSTREAM MONITORING The facility shall conduct semiannual in stream monitoring (one upstream and one downstream of the ash pond discharge) for arsenic, selenium, mercury (method 1631E), chromium, lead, cadmium, copper, zinc, and total dissolved solids (TDS) Instream monitoring should be conducted at the stations that have already been established through the BIP monitoring program- B (upstream of the Outfall 002) and C (downstream of the Outfall 002). The monitoring results shall be submitted with the NPDES permit renewal application. A.(15.) ASH POND CLOSURE The facility shall prepare an Ash Pond Closure Plan in anticipation of the facility closure This Plan shall be submitted to the Division one month prior to the decommissioning of the pond A.(16.) PRIORITY POLLUTANT ANALYSIS The Permittee shall conduct a priority pollutant analysis (in accordance with 40 CFR Part 136) once per permit cycle at outfall 002 and submit the results with the application for permit renewal A.(17.) SEEP POLLUTANT ANALYSIS Seeps with locations identified in Appendix A are classified collectively as Outfall 010. The facility shall continue to implement the Plan for Identification of New Discharges (see Appendix B) to determine if new seeps have emerged Seeps are ephemeral in nature and enter the river at various changing locations. Seeps entering the river from the upstream edge of permittee's property to the downstream property boundary shall be calculated as if entering at one location Page 10 of 15 Permit NC0004961 Permittee shall conduct seep identification survey semi-annually to determine if new seeps have started or that previously identified seeps have significantly changed in size or flow New seeps identified through the seep survey or otherwise discovered or reported to the permittee shall have their flow calculated, be sampled for parameters indicated with results and location(s) reported to Division of Water Resources within 5 days of detection (location only, sampling results shall be submitted within 30 days of sampling) for administrative inclusion in Appendix A Newly identified seeps or seeps whose flow increases will not be considered as new outfalls or wastestream requiring modification of the permit as long as total flow of all seeps does not exceed 0 5 million gallons per day (MGD) and pollutant characterization is similar to previously identified seeps identified in Table 1 and formation of seep(s) or increase in flow was not caused by change in operations by permittee If the pollutant sampling concentration of a new seep exceeds the concentrations in Table 1 the Division will calculate reasonable potential and determine if either administrative inclusion of the seep or formal modification of the permit is necessary Permittee will be notified by the Division within 30 days of receiving the sampling results if permit modification is necessary The maximum allowable parameter concentration in Table 1 is determined by multiplying the highest baseline seep concentration levels by 10 Table 1. Seep Monitoring Parameters and Screening Values Parameter Maximum allowable parameter concentration Maximum allowable total flow for all existing and future seeps Chlorides 73 0 mg/L 0 5 MGD Fluoride 10 0 mg/L 0 5 MGD Total Mercury (Method 1631E) ' 47 0 ng/L 0 5 MGD Total Barium 1 0 mg/L 0 5 MGD Total Iron 65 1 m /L 0 5 MGD Total Manganese 12 3 mg/L 0 5 MGD Total Zinc 190 0 pg/L 0 5 MGD Arsenic' 14 5 µg/L 0 5 MGD Total Cadmium 10 0 µ /L 0 5 MGD Total Chromium 10 0 µ /L 0 5 MGD Total Copper 15 8 µg/L 0 5 MGD Total Lead 25 0 pg/L 0 5 MGD Total Nickel 87 7 pg/L 0 5 MGD Selenium' 25 5 µ /L 0 5 MGD Nitrate/Nitrite as N' 0 17 mg/L 0 5 MGD H 60-90 05MGD TDS 500 0 m L 0 5 MGD TSS 75 0 mg/L 0.5 MGD Temperature monitor 0 5 MGD Specific Conductance monitor 0 5 MGD Notes 1 Technology Based Effluent Limits. The limits can be met by installation of the treatment system, re-routing the discharge to the existing treatment system, or discontinuing the discharge A. (18.) ELECTRONIC REPORTING OF DISCHARGE MONITORING REPORTS (State Enforceable Only) [G.S. 143-215 1(b)] Proposed federal regulations require electronic submittal of all discharge monitoring reports (DMRs) and specify that, if a state does not establish a system to receive such submittals, then permittees must submit DMRs electronically to the Environmental Protection Agency (EPA). The Division anticipates that these regulations will be adopted and is beginning implementation in late 2013. Page 11 of 15 Permit NC000496 r NOTE This special condition supplements or supersedes the following sections within Part II of this permit (Standard Conditzons for NPDES Permits). • Section B (11 ) Signatory Requirements • Section D (2.) • Section D (6 ) • Section E (5.) Reporting Records Retention Monitoring Reports 1. Reporting [Supersedes Section D. (2.) and Section E. 15.1 (a)l Beginning no later than 270 days from the effective date of this permit, the permittee shall begin reporting discharge monitoring data electronically using the NC DWR's Electronic Discharge Monitoring Report (eDMR) internet application_ Monitoring results obtained during the previous month(s) shall be summarized for each month and submitted electronically using eDMR The eDMR system allows permitted facilities to enter monitoring data and submit DMRs electronica=ly using the internet Until such time that the state's eDMR application is compliant with EPA's Cross -Media Electronic Reporting Regulation (CROMERR), permittees will be required to submit all discharge monitoring data to the state electronically using eDMR and will be required to complete the eDMR submission by printing, signing, and submitting one signed original and a copy of the computer printed eDMR to the following address: NC DENR / DWR / Information Processing Un_t ATTENTION: Central Files / eDMR 1617 Mail Service Center Raleigh, North Carolina 27699-1617 If a permittee is unable to use the eDMR system due to a demonstrated hardship or due to the facility being physically located in an area where less than 10 percent of the households have broadband access, then a temporary waiver from the NPDES electronic reporting requirements may be granted and discharge monitoring data may be submitted on paper DMR forms (MR 1, 1. 1, 2, 3) or alternative forms approved by the Director Duplicate signed copies shall be submitted to the mailing address above. Requests for temporary waivers from the NPDES electronic reporting requirements must be submitted in writing to the Division for written approval at least sixty (60) days prior to the date the facility would be required under this permit to begin using eDMR Temporary waivers shall be valid for twelve (12) months and shall thereupon expire At such time, DMRs shall be submitted electronically to the Division unless the permittee re -applies for and is granted a new temporary waiver by the Division Information on eDMR and application for a temporary waiver from the NPDES electronic reporting requirements is found on the following web page http: / /-portal.ncdenr.org/web/wq/admin/­bog/ipu/­edmr Regardless of the submission method, the first DMR is due on the last day of the month following the issuance of the permit or in the case of a new facility, on the last day of the month following the commencement of discharge. Page 12 of 15 Permit NC0004961 2. Signatory Requirements [Supplements Section B. (11.) (b) and supersedes Section B. (11.) All eDMRs submitted to the permit issuing authority shall be signed by a person described in Part II, Section B (11 )(a) or by a duly authorized representative of that person as described in Part II, Section B (11 )(b) A person, and not a position, must be delegated signatory authority for eDMR reporting purposes. For eDMR submissions, the person signing and submitting the DMR must obtain an eDMR user account and login credentials to access the eDMR system For more information on North Carolina's eDMR system, registering for eDMR and obtaining an eDMR user account, please visit the following web page. http //-portal ncdenr.org/web/wq/admin/bog/ipu/edmr Certification Any person submitting an electronic DMR using the state's eDMR system shall make the following certification 140 CFR 122.22] NO OTHER STATEMENTS OF CERTIFICATION WILL BE ACCEPTED '7 certify, under penalty of law, that this document and all attachments were prepared under 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 am aware that there are significant penalties for submitting false information, including the possibility of fines and imprisonment for knowing violations. " 3. Records Retention [Supplements Section D. (6.)1 The permittee shall retain records of all Discharge Monitoring Reports, including eDMR submissions These records or copies shall be maintained for a period of at least 3 years from the date of the report This period may be extended by request of the Director at any time [40 CFR 122 41] A. (19.) APPLICABLE STATE LAW (State Enforceable Only) This facility shall meet the requirements of Senate Bill 729 (Coal Ash Management Act) This permit may be reopened to include new requirements imposed by Senate Bill 729. Page 13 of 15 Permit NC000496I- A. (20.) EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS (Outfall 011) [15A NCAC 02B 0400 et seq , 02B 0500 et seq ] During the period beginning on the effective date of this permit and lasting until expiration, the Permittee is authorized to discharge from outfall 011 — Former Stormwater Outfall 1 Such discharges shall be limited and momtored5 by the Permittee as specified below: EFFLUENT CHARACTERISTICS LIMITS MONITORING REQUIREMENTS Monthly Daily Average Maximun Measurement Sample Type Sample Location Frequency Flow Monthly Pump logs or estimate Influent or Effluent Total Suspended Solids' 23 0 mg/L 75 0 mg/L Monthly Grab Effluent Oil and Grease 110 mg/L 15 0 mg/L Annually Grab Effluent Total Arsenic Quarterly Grab Effluent Total Selenium Quarterly Grab Effluent Total Mercur 6 Quarterly Grab Effluent Nitrate/nitrate as N Quarterly Grab Effluent Total Phosphorus Semi-annually Grab Effluent Total Nitrogen (NO2 + NO3 + TKN) Semi-annually Grab Effluent pH3 Monthly Grab Effluent Turbidity4 Monthly Grab Effluent Notes 1 Monthly average of 43 mg/L is permitted provided that the Permittee can satisfactorily demonstrate that the difference between 23 mg/L and 43 mg/L is a result of the concentration of total suspended solids in the intake water 2. The limits for total copper and total iron only apply during a chemical metals cleaning. 3 The pH shall not be less than 6 0 standard units nor greater than 9 0 standard units. 4 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. NTU - Nephelometric Turbidity Unit 5. No later than 270 days from the effective date of this permit, begin submitting discharge monitoring reports electronically using NC DWR's eDMR application system. See Special Condition A (18 ) 6 The facility shall use EPA method 1631E. There shall be no discharge of floating solids or visible foam in other than trace amounts. Page 14 of 15 Permit NC0004961 Appendix A The permittee has identified 12 potentially contaminated seeps in the areas adjacent to the Mountain Island Lake The locations of the seeps are identified on the map attached to the permit Existing and newly identified seeps shall be sampled on a monthly basis for the first 12 months After the first year the monitoring frequency will be reduced to a semi-annual basis Seep Coordinates and Assigned Outfall Numbers Seep ID Latitude Longitude Outfall number S-1 35.365 -80.967 101 S-2 35.365 -80.966 102 S-3 36 369 -80.965 103 S-4 35.371 -80.963 104 S-5 35.370 -80.963 105 S-6 35.367 -80.958 106 S-7 35 367 -80957 107 S-8 35 365 -80956 108 S-9 1 35 371 -80963 109 5-10 35 369 -80960 110 5-11 35 369 -80960 111 5-12 35 368 -80959 112 Plan for Identification of New Discharges Appendix B Page 15 of 15 Duke Energy Corporation Riverbend Steam Station State Grid/Quad: F15SW/Mt. Island Lake, NC Receiving Streams:Catawba River Sub -Basin: 03-08-33 Stream Class: WS -IV & B -CA Permitted Flow: Not limited Drainage Basin: Catawba River Basin Latitude (001): 35021'28" N Longitude (001): 80° 58' 12" W Latitude (002): 350 22'06" N Longitude (002): 80° 57'31" W Latitude (002A): 35'21'51" N Longitude (002A): 80° 58' 11" W Latitude (011): 35° 21'38" N Longitude (011): 80° 58' 38" W Map not to scale Facility Location North NPDES Permit No. NC0004961 Gaston Coup