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Home My WebLink AboutNC0004774_Permit Renewal_20030222PDuke � Power® A Duke Energy Company December 19, 2003 Mr. David Goodrich In Care of: Ms. Valery Stephens North Carolina Department of Environment and Water Quality Section 1617 Mail Service Center Raleigh, North Carolina 27699 -1617 Natural Resources Subject: Buck Steam Station NPDES Permit # NC0004774 Application for NPDES Permit Renewal Dear Mr. Goodrich: <5& FOSSIL -HYDRO GENERATION Duke Power EC11 E / 526 South Church Street Charlotte, NC 28202 -1802 Duke Power requests the subject permit be renewed and reissued. The above referenced permit expires on June 30, 2004. As required by GS 143- 215.1(C), this permit application for renewal is being submitted at least 180 days prior to permit expiration. Attached is the permit renewal application package which includes the following: 1. EPA Form 1 2. EPA Form 2C - Including Priority Pollutant Analysis 3. EPA Form 2F — Storm Water Discharges 4. Site maps and water flow schematic 5. Supplemental information 6. Assessment of Balanced Indigenous Population Report 7. Historical data for sample reduction request. Having reviewed the previous three years of monitoring data (see attachment) for Outfall # 002 at Buck Steam Station, Duke Power is requesting the following monitoring reductions: Buck Steam Station requests a continuation of the current thermal limits. As noted in the attached Balanced Indigenous Population (BIP) report, there was no adverse impact on the balanced indigenous aquatic community in the Yadkin River, from the operation of Buck Steam Station. This report covers the time period from January 1998 to December 2002. Duke Energy Corporation also requests that the restriction under A (1) for outfall 001, that limits stream flow usage be eliminated. The thermal restrictions are sufficient to protect the aquatic community as indicated by the attached BIP report. www. duke -energy. com Monitoring Frequency Parameter Present Proposed Oil and Grease monthly quarterly Total Copper monthly quarterly Total Iron monthly quarterly Total Selenium quarterly semi - annually Toxicity Testing quarterly semi - annually Buck Steam Station requests a continuation of the current thermal limits. As noted in the attached Balanced Indigenous Population (BIP) report, there was no adverse impact on the balanced indigenous aquatic community in the Yadkin River, from the operation of Buck Steam Station. This report covers the time period from January 1998 to December 2002. Duke Energy Corporation also requests that the restriction under A (1) for outfall 001, that limits stream flow usage be eliminated. The thermal restrictions are sufficient to protect the aquatic community as indicated by the attached BIP report. www. duke -energy. com Per the December 2003 telephone conversation between Charles Weaver, NCDENR, and John Mease, Duke Power, NPDES outfalls #001 and #002 were the only outfalls sampled for the EPA Form 2C parameters This was also agreed to in the 1998 NPDES permit application Under Part I item 11., the wording, used in other NPDES permits provides further clarification on when the Biocide Worksheet, 161 is not required The current wording in other NPDES permits states," Completion of Biocide Worksheet Form 101 is not necessary for'those outfalls containing toxicity testing Division approval is not necessary for the introduction of a new `biocide into an outfall currently being tested for toxicity." It is requested that this wording be included in the, NPDES permit for Buck Steam Station. Buck Steam Station's ,Best Management Practices to control pollutants are the Spill Prevention Control and Countermeasures Plan and the station's chemical handling procedures These plans and procedures can be made available upon request Buck Steam Station's NPDES Outfall #003 has'been eliminated. The transformers have been retired and the outfall pipe has been physically plugged If you have questions or,need additional information, please contact Robert Wylie at (704) 382- 4669: Sincerely, Michael A Ruhe, Manager Environmental Support cc 'Mr- Rex Gleason - NCDENR, Mooresville, N C Ms Trish MacPherson — NCDENR, Raleigh, N C (BIP Report only 3 copies) Buck Parameter History June 2001 - May 2003 (Outfall' 002) Date O &G. Copper Iron Selenium Chronic Toxicity Jun -01 <5'0 <0405 011 Pass Jul -01 <5 0 <0.005 006 Aug-01 <5 0 0 005 008 23 Se -01 <5.0 <0 005 006 Pass Oct -01 <5 0 0 007 012 Nov -01 <5.0 _ 0 005 010 <2 0 Dec -01 <5 0 0 010 010 Pass Jan -02 <5 0 0 009 014 Feb -02 <5 0 0 006 018 <2'0 Mar -02 <5 0 <0 005 021 Pa_ ss A f -02 <5 0 01005 015 Ma =02 <5 0 0 006 013 <2.0 Jun -02 <5 0 0 006 _ 023 Pass Jul -02 <5.0 0 006 027 Aug -02 <5 0 0 005 U 17 25 Sep -02 <5.0 0 005 012 Pass Oct -02 -550 0 006 013 _ Nov -02 <5 0 0 005 012 <2 0 Dec -02 <5 0 0.008 014 Pass Jan -03 <5 0 <01005 027 Feb -03 <5 0 0,005 022 Mar -03 <5 0 <0 005 054 <2 0 Pass Apr-03 <5 0 <0.005 022 'Ma' -03 <5 0 <0 005 024 EPA 2C <5 0 0 004 012 <2 0 12/1'0/2003 1 � A _ Ltd;; 124 PMPWVLkle N 0 02 a4 No 0 02 0.4 _ 06 q• DisdIM Putts' usdimp W Sauce 001 OMd3w Oo*V VYar asdMe 002 AshR)eMD%tSfW 002A V4sWV P Duke power Company B", TEAM STATION 004 ktie screen Bad*ash 005 M= t "pnertCoo" PEES DISC ARGE PUNT'S E ca rn m 0 U fB � E N C) � O U O U) U �' 03 Z c oU Z (D 4— c cu, o c o cU w Ez �a a� U) U m CM moLO CD O r NC #0004774, Page 2 of 23 December'2003 General Information Buck Steam Station (BSS) consists of four steam electric generating units and 3 combustion turbine units. BSS utilizes water drawn from the Yadkin River at the upstream end of High Rock Lake. After various uses,and treatments, ,plant effluents discharge back into the Yadkin River. A schematic flow diagram of 'Water use, treatment, and discharge is attached: Outfall 001 - Candenser Cooling Water (CCW) The CCW system is a once through non - contact cooling;water system that removes heat rejected from the condensers and other °selected heat exchangers. Each of the four BSS operating units has two condenser cooling pumps which have the following capacities: Unit 1 Retired Unit 2 Retired Unit 3 1 pump - 485000 GPM Unit 4 1 pump - 25,000 GPM Unit 5 1 pump - 5,5,000 GPM Unit 6 1 pump - ,55,000 GPM CCW Pump Capacity 2 pumps - 71,000 GPM 2 pumps - 37,000 GPM 2 pumps - 83,000 GPM 2 pumps - 83,000 GPM The operational schedule for these pumps is dependent on the intake�water temperature and on the unit loads. Depending on the electrical demand, pumps are operated to maximize BSS efficiency and' to assure balanced and indigenous populations are maintained in the Yadkin River. During cold weather, ice can build up in the station intake and make water withdrawal difficult. When this occurs, 'a portion of the warm condenser cooling flow is diverted back to the intake to melt the ice. ,However, this is done on a very limited basis. The maximum'flow is 42,000 gpm when used. Because this discharge is used only when the units are operating, the warm discharge is immediately pulled back into the plant through the, CCW system. Condenser cleaning is accomplished mechanically. After the condenser is drained, loose so'hd material'is blown from the tubes and removed by hand. Mud and slime are removed by forcing rubber plugs through the tubes with air and water. The condenser tubes are cleaned in this manner upproximately two times per year per unit. NC #0004774, Page 3 of 23 Decembei-,2003 Closed Cooling Systems The Recirculated Cooling Water (RCW) system is used for cooling various station components. The CCW system is used to cool the RCW system. The RCW system is a relatively small closed cooling system'that`uses maintenance chemicals (microbiocides and corrosi`on,inhibitors) in order to prevent biofoulmg and system corrosion. The primary corrosion inhibitor used in this system is ,sodium,nitrite The potential exists for minor plate leaks to occur. If a plate leak occurs, the leak may discharge into the CCW system. Routine system, monitoring for nitrite, concentrations and make -up water, provides input that assists in determining a tube leak. Once a leak is identified corrective measures will be implemented to minimize and repair the leak, During a leak the concentration of the =maintenance chemicals will not exceed the No Observed Effect Concentration (NOEC). The RCW and',chiller systems are required to be cleaned periodically: The cleanings may use a dispersant, wetting agent and detergent. In addition leak detection is conducted using,,a fluorescing dye. While these are closed systems, they are drained on a non- routine basis, as necessary for maintenance; to the sump and pumped to the ash basin (outfall 002). Outfall 002 - Ash Basin Make -Up Water Process Wastes The water treatment wastes at BSS are made up `of sedimentation, filter backwash, demmeralizer regeneration Wastes and boiler blow down., The make -up water °treatment system is comprised of a clarifier, pressure filter, activated carbon filters and a demmeralizer with two cells. Make -up water is fed' to the boilers to generate steam to turn'the turbines. On occasion,a vendor may be used with a mobile water treatment unit to augment the facility water treatment capacity. Vendors will use-traditional water treatment methods. The followmg;provides more specific information on the process Water treatment system Clarifier. The clarifier utilizes a continuous feed of Nalco 81u05 cationic water treatment polymer, Calgon CA -25 clay and chlorine in order to maintain an average of 3 ppm, 30 ppm and' f ppm, respectively. The solids in the clarifier ate desludged as needed to the floor drains and then pumped to the ash basin. BSS may, alter this process to supply site clarified NC #0004774, Page 4 of 23 December 2003 water by other traditional water treatment methods and using traditional chemicals' other than those identified above Gravity Filters: Five ,gravity filters used for removal of colloidal material are'backwashed, as necessary, dependent upon the level of solids in the intake water Each filter is backwashed approximately once,per week with water from the filtered water tank. This flow is discharged to the floor drains, which flow to the unit 5 and 6 pump room sump. The filter medium is composed of a total of 620 ft3 of anthraciteecoal Activated Carbon Filters: Two activated carbon fifters remove organics and the ehlofine that is, infected in the clan'fier. These filters are backwashed approximately-once per'week. The-wash water,is discharged to the floor drains, which flow to the, 3 and 4 pump ,room ,sump: Approximately 140 ft3 of activated carbon is replaced as needed. This spent carbon is carried to the coal bunker, fed through the coal mills and ultimately incinerated in the boilers Demineralizers: Each of the two mixed bed ionic exchange demmeralizer cells has a capacity of 160 gpm, but is normally operated ut 120 gpm. On the average one ce11 is regenerated every other day. A regeneration demands 20 gallons of 93% sulfuric acid and 80 gallons of 50% o sodium hydroxide. The acid and caustic are fed into different areas of the cell simultaneously and substantially neutralize each other upon discharge. Approximately 12,000 gallons of filtered water is used per regeneration, which further dilutes the chemicals. ' The demineralizer ion exchange resin is replaced approximately once every 5 to 8 years and the spent resin (294 ft3) is discharged to the ash basin. Approximately twice a year each,demineralizer bed is brine treated This process uses approximately 2,0.001bs. of salt (sodium chloride) mixed with approximately 2,000 gallons of filtered water for each bed treatment. The discharge of this treatment water, as well as demineralizer regeneration effluent, flows to the unit 5 and 6 pump room sump. NC #0004774, Page 5 of 23 December 2003 Boiler Blowdown Water wall and continuous blowdowns, as well as superheater drain lines from boilers -8 and 9 (umts 5 and ,6) ,discharge to a,common tank that is vented to the atmosphere The remaining liquid in the tank discharges at a maximum average rate of 130,000 gpd to station floor drains. Waterwall and continuous blowdowns from boilers 5, 6, and 7 (Units 3 and 4) discharge to a common tank that is also vented to the atmosphere. The remaining.liqui'd in the tank collectively discharges a maximum average rate of'21,400 gpd to station-floor drains. The station floor drains are pumped to the yard,sump and then to the, ash basin. Hydrazine is infected into the condensate system as an oxygen scavenger Most of the hydrazine is utilized and converted to ammonia and water, which 'is u"sed for pH control; however, trace amounts of hydrazine (< 10,ppb) may be found in the boiler blowdowns 1 Boiler, Cleaning The boilers at BSS are chemically cleaned on an as needed basis. Normally the cleanings occur on a 5 to 7 year frequency. The cleaning process is performed in two stages with a boiler tube sample being the determining factor If both stages are required, then approximately 266,000 gallons of water and chemicals are used per boiler for each chemical cleaning fob. Listed below are the chemicals and amounts (subject-to change) presently used at,BSS per cleaning: 1St State Chemical Ammonium Biflouride Ammonium Bicarbonate Citric Acid Copper Complexer Hydrochloric Acid, 200 Be' (31.5 %) Sodium Sulfite Corrosion Inhibitors Amount used ner Unit 1,000 lbs. 1,000 lbs. ,200 lbs. 1,620 lbs. 3,300 gals. 100 lbs. ,(as necessary) 9 2ND Stage Chemicals Ammonium Hydroxide, 260 Be' .Sodium.Bromate Sodium Carbonate Amount used per Unit 850 gals. 550 lbs. 2,000 lbs. NC #0004774, Page 6 of 23 December 2003 The waste solution is discharged to the, ash basin along°with the normal ash sluicing flow to the m drain. lmediately�prior to the beginning of a boiler chemical cleaning procedure, additional stoplogs are added to the ash basin discharge structure .to stop. the discharge. This assures longer retention time of the chemical wastes for proper treatment through dilution, neutralization, precipitation, and ion= exchange as documented in the Ash Basin Equivalency Demonstration (October 1976)., The discharge is held up a minimum of 96 hours following the first chemical drain and additional sampling for pH, iron and copper is performed once discharge begins. Storm Water to Ash Basin The ash basin at BSS accommodates storm water flows from the yard drainage sump and rainfall run- off,from the basin watershed area. The average rainfall run -off flows are based on 44 inches of rain per year with 100% run -off from the pond surfaces° and 50% run -off from other areas. The average run -off for the ash basin watershed area is 0.299 MGD The coal yard drainage at BSS drains to, the wastewater sump and is then pumped to the ash basin. The coal yard has an average run -off of 0.065 MGD based on 44 inches of rain per year with 50% run -off. Averaged over a typical year, the total storm water run -off that goes to the ash basin, is approximately 0.364 mgd Effluents from Air Pollution Control Devices Electrostatic precipitators are used for the control of air pollution at BSS. The collected fly ash is sluiced to the ash settling basin, Continuous Emission Monitors (CEM) produce potassium permanganate during normal operation at a rate of approximately 1 lb /quarter which is sluiced to the ash basin. Additionally, approximately twice per year the electrostatic precipitators are sprayed with a caustic solution to improve their operation. This wastewater ultimately,is discharged to the ash basin. This operation has notwarranted any additional treatmenttby the ,ash basin in order to comply with the pH limits. NC. #0004774, Page 7 of 23 December 2003 Sanitary Wastes BSS uses an onsite well for its sanitary and potable water needs. The °well water passes through a water softening system, a reverse osmosis system and is then chlorinated for disinfection purposes. The water conditioner is regenerated once every 25,000 gallons for 2 hours. The regeneration demands approximately 1,600 lbs of water softener salt pellets per month and 1,200 gallons, of water per regeneration. The estimated average flow of domestic waste is 0.002 mgd The effluent from the package sewage treatment plant is discharged to the yard sump and then to the ash basin Floor Drains The floor drams in the powerhouse connect to sumps where they are pumped to the ash basin These drains can receive'mputs from spillage or leakage, floor wash water, as well as flows° from water treatment processes The following are materials that are stored'inside the powerhouse• • sulfuric acid • sodium hydroxide • water treatment chemicals • ammonium hydroxide • industrial cleaning;products used for general housekeeping • hydrazine • oil, lube oil (recycled) Miscellaneous Closed Cooling Systems, Several plant,cooling systems, are recirculating systems and therefore require the addition of microbiocides, and corrosion inhibitors to prevent biofouling and piping corrosion While these are closed systems, they are drained on a non - routme basis, as necessary for maintenance, to the sump and pumped to the ash basin. NC #0004774, Page 8 of 23 December 2003 ,Non- Contact Cooling Water Once through non - contact cooling water from powerhouse air compressors, ,discharge into the plant's sump system This discharges into the, ash basin. Lab Wastes The chemistry lab on site performs a variety of water analyses and routine sample collection. Therefore, several chemicals are used in the lab in small quantities for sample preservation, bottle nnsmg,, equipment calibration, etc The wastes are poured down the sink, discharged into the package sewage treatment system and then pumped to the ash basin. Dredge Material: Because silt settles in front of the plant intakes, dredging is done as necessary to assure a clear intake. In order to monitor the discharge of the return water from the dredging activity, all dredge, material is pumped to the ash basin for additional treatment. Groundwater Remediation: A total product, recovery system has been installed at BSS in orderto remediate groundwater due to a previous oil leak from an underground storage tank. Approval of an Authorization to Construct (ATC) was granted on February 10, 1997' A maximum of 20 gpd,of water is discharged through an oil water separator to the yard sump and then is pumped to, the ash basin. Turbine Non - destructive Testing, Approximately once per year, one, turbine is tested for cracks in the generator shaft using an ullrasomc non - destructive, test. Dunng ,the process, one hundred gallons of demmerahzed water mixed with one gallon of corrosion inhibitor is used and discharged to the ash basin. PH Control During warmer periods of the year, algal blooms occur in the ash basin causing pH levels to rise. A CO2 mjection.system is used prior to the 002 discharge to maintain the pH level below 9.0 ,standard units. Periodically, acid and/or caustic addition may be warranted to properly adjust the pH prior to discharge. .NC #0004774, Page 9 of 23 December 2003 X Ray Process Wastewater Periodically welds may need to be x rayed as part of a quality assurance step- The process used to develop the x rays creates a small waste stream. Once generated the wastestream is characterized and disposed of accordingly. The disposal is typically to the ash basin. De -Icing Products In order to prevent accidents due to ice on site road's -and sidewalks de -icing products are used as needed per the manufacturers recommendations. The run -off from this application either goes to the,Yadkm River via a storm drain or the ash basin discharge. O.utfall 002A — Ward Sump Overflow An overflow pipe that directs flow from the sump to the Yadkin River was included in the construction of the yard sump. This was, done to prevent submergence and damage of the sump's pump motors in the event that all pumps fail or the redundant power supply does not restore power in a timely manner. Outfall_003 — Transformer Cooling Water 'This outfall has been eliminated.. Outfal1004 - Intake Screen Backwash Intake screens are backwashed'at a rate}of 255,000 GPD with untreated river water. The solid material' washed from the screens is collected by a trough and returned to the' lake below a retaining wall downstream from the�plant intake. The debris collected on the screens consist mainly of twigs, leaves and other materials indigenous to the river and is therefore returned to the ,river without any adverse environmental impact r � NC #0004774, Page 10 of 23 December 2003 Discharge 005 - Miscellaneou§ Equipment Cooling Water Several systems (noted below) use once through non - contact cooling water, These systems all discharge in the same vicinity (station intake area) Their discharge water is pumped back through the CCW "system and discharged out outfall 001. The systems are as follows, • Turbine lube oil coolers • Condensate coolers • Induced Draft fans • Force draft Mans • Unwateri'ng pumps All of 'the above cooling water discharges to the BSS's intake for a total combined average flow of 4 1 mgd Storm Water D'isch'arges to the Yadkin River There are thirty six storm Water outfalls at BSS thatd'ischarge storm waterrun -off directly to the Yadkin River. Attached'is a siteplan drawing that provides the drainage areas and topography for each outfall. Samples Were collected from storm water outfalls that are representative of the site. These outfalls are 2, 3, 48 and 56. The results of these samples are included.on the attached Form 2F. The following provides a description of the'storm water outfalls at BSS. Site Description The site covers approximately 643 acres. The powerhouse, the plant yard, the coal yard, the switchyards, and the combustion turbines cover about 50 acres. These developed areas are generally flat. There are approximately two miles of rail access and two miles of paved - roadways on -site. Total acreage for the three ash "settling basins is approximately 83 acres. Runoff from approximately 292 acres drains to the ash settling basins. The site is located in the eastern portion of the Charlotte Belt in the Piedmont Province. Soils at Buck Steam Station are typical of the region Soils are primarily micaceous fine sandy silts with some fine sandy silty clays. The site topography is generally flat with rolling hills in outlying, undeveloped areas. In developed areas, runoff, flows overland to ditches and catch basins, which are connected to a buried network of corrugated metal pipes (CMP). Storm water 'from areas with significant materials or activities is routed through treatment systems prior to discharge. Rainfall' runoff from the plant yard, coal handling areas, the coal' yard, and fueling areas goes to the yard sump, NC #0004774, Page 11 of'23 December 2003 ' which discharges to the, ash basin. Rainfall runoff from the combustion turbine area and most of the switchyards is routed through oil trap tanks Other storm water discharges come mostly from either roof drainage or undeveloped areas. Facility Drainage and Inventory of Significant Materials and Controls A description of the drainage area, significant matenals, and material control measures is presented for each drainage basin, In addition to the significant materials particular 'to each drainage basin, herbicides are applied to selected areas throughout Buck Steam Station to eliminate- undesirable vegetation along railways, ash pipelines, and the perimeter fence Herbicides are, also applied, as needed, in the ,gravel parking lots, switchyard, and laydown areas. Herbicides, are sprayed around the yard sumps„ transformers,, trailers, and the intake structure All herbicides used at Buck Steam Station are approved by the, company as environmentally safe and are applied in an environmentally safe ,manner and quantity. • Storm Water Outfall 1 Discharge Structure- 15 inch ("),diameter (�) CMP Location: West of Units 5 and 6 Switchyard Control Structure- 8,000 gallon oil trap tank Drainage Area: 3.4 acres Area Descnption This drainage area ;includes a portion of the Units. 5 and 6 switchyard; about 1/3 acre of the switchyard lie within this area The-switchyard is covered with gravel and concrete., About 1/2 acre of the station parking lot lie within this drainage basin. There are some landscaped,,areas along the station entrance road. 'There are about 800 feet of railway lines at the southeast boundary of the area. The remainder of the drainage area contains grassy, open areas. Approximately 15 percent of 'this drainage basin is paved. Significant Materials / Controls, Oil- Sw,i'tchyard equipment in the Units 5 and 6 switchyard contains a total of 60,916 gallons of mineral oil. The largest volume contained by any single component isz 5,250 gallons. Storm water from this area is�processed through an 8,000 gallon oil trap tank. 0 Storm Water Outfall 2 Discharge Structure.' 21" � CMP Location: West of Units 5 and 6 Switchyard Control Structure: 12,000 gallon oil trap_ tank Drainage Area: 2.6 acres Area Description This drainage area includes the majority of the' Units 5 and 6 switchyard, about 1 acre. The switchyard is covered with gravel and concrete. About 1/4 acres, of pavement beneath the #8 and . r 4 ` NC #0004774, Page 12 of'23 December 2003 #9 precipitators- are contained within this drainage basin. The remainder of the drainage area contains grassy, open areas. Significant Matenals� / Controls Oil: Switchgear equipment in the Units 5 and 6 switchyard contains a total of 60,916 gallons, of mineral oil. ° The largest volume contained by any single, component is 5,250 gallons There are six transformers for the #8 and #9 precipitators, and each transformer contains 148 gallons of mineral oil. Storm water from this basin is processed through a 12,000 gallon oil trap tank. O Storm Water Outfall 3 Discharge Structure: 10" � CMP Location: West of Powerhouse Drainage Area: 0 5 acres Area Description Roof drainage from the service building is discharged through thin outfall Roof area for the service building is about 3,900 ft2. Landscaped areas account for about 1/4 acre within `this drainage basin. Compressed gas cylinders are stored 'in this drainage basin near the chlorine house. About 25 percent of the drainage area is roofed. Condensate from the air conditioning system. is discharged through this outfall. Significant Materials / Controls Oil: There, is a 150- gallon aboveground storage tank located along the west powerhouse wall near the Chlorine House. The, tank is used to capture oil extracted from vapors vented from the turbine lube oiltank inside the powerhouse. The tank is contained within concrete curbing approximately 1.5 feet high. Storm water can be released.from the containment pit 'by opening a valve, which is normally closed. Storm water caught within the containment area is inspected' for any traces of oil prior to its release. If oil were found, it would be removed using oi tank - The absorbent mats. There is a 55- gallon barrel adjacent to the storage tan The barrel is used to collect oil from the tank for disposal. • Storm Water Outfall 5 Discharge Structure- 4" � Steel Pipe Location: North Face of Powerhouse Drainage- Area: 2,000 ft2 Area Description This outfall conveys roof drainage from a portion ,of the turbine room roof at Units 5. and 6. `100 percent of the drainage area is roofed. Si'gmficant Materials / Controls Significant materials are not stored within this drainage basin. NC #0004774, Page 13 of 23 December 2003 • Storm Water Outfall 7 / NPDES 005` Discharge Structure- 8" � Steel Pipe Locat'iori: North Face of Powerhouse 'Drainage Area: 18;380 ft2 Area Description Thfs outfall conveys roof drainage from portions of the turbine and boiler room roofs at Units 5 and 6. 100 percent of the drainage, area is roofed. The floor drains from the chemical ,storage level discharge to this outfall. Non -storm water discharges are conveyed through this outfall. These discharges include non - contact cooling water from the Units 5 and 6 pre- heaters and the ID fan bearings and couplings. These discharges are permited as NPDES outfall 005. Significant Materials / Controls Storm water runoff 'in this drainage area is not exposed to any significant materials. • Storm Water Outfalls 11 and 15 Discharge Structure. 4" � Steel Pipe Location: Intake Room at Units 5 and 6 Drainage Area: 1,420 ft2 each Area Description These outfalls convey roof drainage from the intake room at Units 5 and 6. 1,00 percent of the drainage area is roofed. Significant Materials, /,Controls Significant materials are,not stored within this drainage basin • Storm Water Outfall 16 Discharge Structure: 6" � Steel Pipe Location: North Face of Powerhouse Drainage Area: 12,480 ft2 Area Description This outfall conveys roof drainage, from the turbine and boiler room roofs at Units 5 and 6. 100 percent of the drainage area is roofed Significant Materials / Controls Significant materials are not-stored within this drainage basin. NC 0004774, Page 14 of 23 December 2003 ® Storm Water Outfall 23 Discharge Structure: 4" � Steel Pipe Location: North Face of Powerhouse .Drainage Area: 7,340 ft2 Area Description This outfall conveys roof drainage from the machine shop and turbine room roofs at Units 5 and 6 100 percent of the drainage area is roofed. Significant Materials / Controls Significant materials are not stored within this drainage basin. • Storm Water Outfall 58 / NP,DES 005 Discharge Structure: 5" � Steel Pipe Location. North Face of Powerhouse Drainage Area: 6,310 ft' Area Description t This outfall conveys roof drainage from portions of the turbine and boiler room roofs at Unit 4. 100 percent of the drainage area is roofed Non -storm water discharges are, conveyed through this outfall. These discharges include non - contact cooling water from the Umt 4 pre- heaters and the ID and FD fans. These discharges are permitted as NPDES outfall 005. Sigmficant Materials / Controls Significant materials are not stored within this drainage basin. • Storm Water Outfalls 25 and 27 Discharge Structure: 4" � Steel Pipe Location: Intake Room at Unit 4 Drainage Area: 435 ft2 each Area Description These outfalls convey-roof drainage from the intake room at Unit 4. 100 percent of the drainage, area is roofed. Significant Matenals / Controls ,Significant materials are not stored within this drainage basin. 0 Storm Water Outfall 32 Discharge Structure: 4" � Steel Pipe ,Location. North Face of Powerhouse Drainage Area: 33,120 fie A ii 1 H NC #0004774, Page 15 of 23 December' 2003 Area,Descnption This outfall conveys roof drainage .from the turbine room roof at` Units 3 and. 4. 100 percent of the drainage area is roofed. Sigmficant Materials / Controls, Significant materials arenot stored within this drainage basin • 'Storm Water Outfall 34 / NPDES 005 Discharge Structure: 4" � Steel`Pipe Location: North Face of Powerhouse Drainage Area: 2,720 ft2 Area Description This outfall conveys roof drainage from portions of the turbine room roof at Unit 3. 100 percent of the drainage. area is roofed Non -stone water discharges are conveyed through this outfall. These discharges mclu& non - contact cooling Water from the Unit 3 pre = heaters and the ID and FD fans. These discharges are permitted as NPDES outfall 005. S'i mficant Materials / Controls Significant materials are not stored Within this drainage basin. Y Storm Water�Out'falls 35arid 38 Discharge Structure- 4" � Steel Pipe Location: Intake Room at Unit 3 Drainage Area: 655 ft2 each Area Deescnption These outfalls convey roof drainage from the intake room at Unit 3. 100 percent of the drainage area is roofed. Significant Materials' / Controls Signfficantmaterials are not stored within this drainage basin. • Storm Water Outfall 39 Discharge Structure: 4" � ,Steel Pipe Location* North Face of Powerhouse Drainage Area. 2080 ft' Area Description This outfall conveys roof drainage from the turbine room roof at Unit 3. 100 percent of the drainage area is roofed. NC #00,04774, Page 16 of'23 December 2003 Significant Materials / Controls Significant matenals are not stored within this drainage basin • Storm Water Outfalls 65 and 68 Discharge Structure: 4" � Steel Pipe Location- North Face of Powerhouse Drainage, Area- 6,100 ft2' each Area Description 'These outfalls convey, roof drainage from, the turbine and boiler room roofs at the retired Units 1 and 2. 100 percent of the drainage area is roofed. Significant Materials % Controls Significant materials are not stored within this drainage basin. • Storm Water Outfalls 66 and 67 Discharge Structure: 4" � Steel Pipe Location: North Face of Powerhouse° Drainage Area--- 4,850 ft2 each Area Description These outfalls convey`roof drainage from the turbine, and boiler room roofs at the retired Units 1 and 2. 100 percent of the drainage area is roofed. Significant Materials / Controls Significant materials are,not stored within this drainage basin. • Storm Water Outfalls 69, 70, 71, and 72 Discharge Structure: 3" � Steel Pipe Location- Intake Room at Units 1 and 2 Drainage Area- 510 ft2 each Area Description These outfalls convey roof drainage from the intake room at the retired Units 1 and 2 1,00 percent of the drainage area is roofed. Significant Materials / Control's Significant materials are not stored within this drainage basin. O Storm Water O.utfalls 48 and 57 Discharge Structure: 15" � Steel Pipe Location: Units 3 and' 4 Switchyard Drainage Area: 1.0 acre total NC #0004174, Page 17 of 23 December 2003 Area Description These outfalls convey storm water runoff from the Units 3 and 4 switchyard and from conduit manholes. The, switchyard is covered with gravel. Significant Materials / Control's Switchgear equipment in this switchyard ,contains a total of 33';845 gallons ,of-mmeral oil. The largest volume contained by any single component is 6,120 gallons. All ,of the equipment is surrounded by concrete,dikes'to contain spills. ® Storm Water Outfalls 51, 52, and 53 ;Discharge Structure, 4" Terra Cotta Pipe Location: Conduit'Manholes in Units 3 and 4 Switchyard Drainage Area: 200 ft2 maximum Area Description These outfalls convey storm water caught inside conduit manholes Significant Materials,/ Controls Significant materials ate not stored within this drainage basin. • Storm Water Outfall 56 Discharge Structure: 36" � CMP Location: Between the Umts'3 and 4 Switchyard and Yard Sump Control Structure: 30,000,and 65,000 gallon oil trap tanks Drainage Area: 46.3 acres Area Description The combustion turbines, the aboveground fuel oil bulk storage tank, and the fuel oil unloading area are located within this drainage basin. The combustion turbine area encompasses about 2.5 acres, most of which is covered with gravel. Roofs of the combustion turbine control room and boathouse cover about 4,000 square feet There is a small' lay down storage area within the combustion turbine area The fuel oil bulk storage tank and its containment dikes utilize approximately 2.5 acres. The paved fuel oil unloading area is 'located northwest of the bulk storage tank and covers about, 1/4 acre. There is approximately 20, of a mile of paved roadways Within this drainage basin: Most of this drainage basin is open space, either mown grass or undeveloped wooded areas. Paved and roofed ,areas account for approximately two per cent of this drainage area. Significant Materials / Controls Oil The fuel oil, bulk storage tank is an aboveground, galvanized steel cylinder surrounded by an earthen berm sufficient in height to contain a total spill plus rainfall The original capacity of the tank was 3,000,000 gallons, but it has been modified to limit its capacity to 649,000 gallons The amount of fuel oil normally stored in the tank ranges between NC #0004774, Page 18 of 23 December 2003 400,000 gallons in summer and 600,000 gallons in winter. Rainfall collected within the containment berm is inspected for the presence of oil. If no oil is present then the rainwater is drained through a,manually operated siphon to an adjacent ditch. The majonty of piping on -site runs aboveground with a limited amount of underground piping. Piping runs throughout the site carrying fuel oil from the unloading area to the bulk storage tank and from the tank to the combustion turbine area, the station, and dispensers. In the fuel oil unloading area, fuel is transferred from an 8,000 gallon tanker truck to the bulk storage tank via the pipelines. DOT unloading procedures are followed. There is also a small fuel oil loading station where fuel oil can be transferred from the pipeline to tanker trucks Each combustion turbine unit contains about 200 gallons of ,fuel oil. If a unit were to malfunction, this fuel oil would drain to ;an abort tank. Lube oil tanks for the combustion turbine units contain a total of 525 gallons of lubricating oil. 55- gallon drums are stored inside a concrete containment pit near the maintenance shed Ash' Ash pipelines run through this area carrying ash from the plant to the ash basins. There are two oil trap tanks to process storm water runoff from this basin. The first tank in the series has a capacity of 3'0,000 gallons, and the second 'tank has a capacity of 65,000 gallons. Runoff from some portions of the drainage basin passes through both tanks, while runoff from other portions of the basin passes through the 65,000 gallon tank only. 'There .is, a chance that runoff from the upper portions of this drainage basin could cross over into the drainage basin for the yard sump,, depending upon ,the overland flow path. • Storm Water Outfall 62 Discharge Structure: 36" � CMR Location: West of Station Entrance Road Control Structures 60,000 and 65,,000 ,gallon oil trap tanks Drainage Area: 11.9 acres Area Description This drainage area includes the 230 kV and 100kV switchyards. The switchyards cover about 2 2 acres', and they are surfaced with ,gravel. The remainder of the drainage basin is grassy, open areas. There are about 1,200 feet of gravel roads within this drainage area The. paved road to the fuel oil unloading area forms a portion of the south and east boundaries of this basin. Less than 1% of this drainage area is paved Significant Materials / Controls Oil: Switchgear equipment in these substations contains a total of 85,038 gallons of mineral oil. The largest volume contained by any single component is 20,300 ,gallons. The 100 kV switchyard drains to the 60,000 gallon oil trap tank. Most storm water from the 230 kV NC #0004774, Page 19 of 23, December 2003 switchyard is processed through the 65,000 gallon oil trap tank. Storm water from two catch basins at the weste_rn,perimeter of the 230 kV switchyard is,not processed through the oil trap tanks. • 'Storm Water Outfall 64 Discharge Structure: 1`2" � Steel Location- East of Units 3 and 4 Switchyard Drainage Area: 0.5 acres Area Description This drainage area includes a portion of the railroad tracks Significant Materials / Controls 'Coal: Coal dust and residue can be deposited along the tracks. • Storm Water Outfall 73 Discharge Structure 112 "', Steel Location. Northeast end of railroad tracks Drainage Area. 16:3 acres Area Description This drainage area includes a portion of the railroad tracks. The remainder of the drainage basin is wooded. Significant Materials / Controls Coal: Cowl dust ,and residue can be deposited along the tracks • Storm Water Outfall 74 Discharge Structure: 12 inch ( ") diameter (�) Concrete, Location. West of Units 5 and 6 Switchyard Drainage Area: 2.1 acres Area Description This drainage area includes the parking lot. Significant Materials / Controls Significant materials are not stored within this drainage basin. • Storm Water Outfall 75 'D'ischarge Structure- 30 inch ( ") diameter M CMP Location: East of Units 3. and 4 Switchyard Drainage Area: 10,000 ft, 'h NC #0004774, Page 20 of 23 December 2003 Area Description This drainage area,includes a portion of the Units railroad tracks. Significant Materials / Controls Significant,matenals are not stored within this drainage basin Table 2c -3 Hazardous and Toxic .Substanc'es At BSS, the potential for a, toxic and/or hazardous substances being discharge is very low. In reference to Item V -D of Form 2 -C, the substances identified under Table 2c -3 that may be 'm the ash basin discharge,are as follows: Asbestos Asbestos is present in parts of the station "s insulation. The potential exists for asbestos to be released during an asbestos removal and handling operation and through degradation of insulation. The amount of asbestos in the ash basin is expected to be at extremely low concentrations. . Cyclohexanone: Cyclohexanone is contained in thinners and solvents. The amount of cyclohexanone on- site this past year was less than 15 pounds. Therefore, any cyclohexanone in the ash basin would be at very low concentrations. Xylene: Xylene is primarily at BSS in gasoline and diesel fuel. Secondary containment systems are in place in order to prevent xylene from reaching the ash basin. If any xylene did reach the ash basin it, would beat very low concentrations. Others During the course of the year, products such as commercial cleaners and laboratory reagents may be purchased which contain very low levels of a substance found in Table 2c -3. Thus any discharge of these products to the ash basin will be at very low concentrations. 40 CFR 117 and CERCLA Hazardous Substances The Hazardous Substance Table below identifies hazardous substances located on -site that may be released to the ash basin during a spill in quantities equal to, or greater than the reportable quantity (RQ) levels as referenced in' 40 CFR 117, 302 and 355. This list is being °provided in order to qualify for "the spill reportability exemption under 40 CFR 117 and'the Comprehensive, Environmental, Response, Compensation and Liability Act. Substance Hydrazine Sodium Hydroxide 'Sulfuric Acid Ash Basin Capacity Hazardous Substance Table Quantity Ubs.) 1,026 22,330 34,694 NC' #0004774, Page 11 of 23 December 2003 'Source Boiler Room Caustic Tank Acid Tank Special Condition A (t2) of the existing NPDES permit requires that the ash basin be evaluated and a ,report submitted to your office that ensures adequate volume exists to contain solids; rainfall runoff and the maximum dry weather flow. The following calculations indicate that the ash basin will have sufficient available capacity through the year 2010. Estimate Runoff to the, Ash Basin from a 10 -yr 24 -hr storm: Determination of Wet Weather Detention Volume: Wet Weather Detention Volume is the sum of the runoff accumulated in the ash basin which.results from a 10 -yr 24 -hr storm (assuming 100% runoff) plus the maximum 24 -hr dry weather waste stream which discharges to the Ash Basin (refer to NPDES Permit NC0004774)� 1 Natural Drainage Area of Ash Basin Additional Primary Cell 1730 Acres Old Primary Cell 1520 Acres Secondary Cell 47.0 Acres Station Yard ,Drainage Area 'Pumped to Ash Basin = 270 Acres Total 399.0 Acres 2 Precipitation from 10 -yr 24 -hr storm = 5 1, Inches 3. Total Stormwater Runoff to Ash Basin = 169 58 Acre -feet (Assuming 100% runoff) II Estimated Maximum 24 -hr Dry Weather Waste Stream Discharging to Ash Basin. 1 Maximum recorded Ash Basin Discharge = 6',000,000 Gallons /day 2 Increase maximum daily discharge by 10% for conservatism and convert units to acre -feet = 1 20 25 Acre -feet III Wet Weather Detention Volume Sum of Parts I and 11 = 189 83 Acre -feet NC, #0004774, Page 22 of 23 December 2003 IV. Estimated Quantity of Solids (Ash) to be discharged to Ash Basin through December 31, 2010, Time Period Actual or Estimated Coal Consumption 1,000's tons % Ash Estimated Ash Production (1000's tons ) Disposal Contracts (1000's tons Estimated Ash Disposal to Basin (1000's tons Estimated Ash Disposal to Basin Ac -ft 6/1/1989- 1'2/31/1989 1450 10.11% 1466 00 147 122 1990 981 928% 9.10 00 9.1 76 1,991 144.4 & 78% 1268 00 427 M6 1,992 2402 989% 2376 0'0 238 1'9.8 1993 265.3 9 31 % 24.70 00 24 7' 206 1994 2054 988% 20:29 00 20.3 169 1995 171.5 1028% 17.63 00 17.6 14.7 1996 6224 11,06% 6884 00 688 57.5 f 997 756.7 11.98% 90 65 Q 0 907 757 1998 607.5 1358% 82.50 00 825 '68'9 1999 702.6 12 61 % 8860 391 2 479'8 4006 2000 7748 1364% 10569 24 1081 90.2 2001 7061 15.36% 10.8.46 0.0 1.085, 905 1-/112002 - 10/31/2002 510.7 16.21% 82-78 00, 828 691 11/1/2002- 12/31 /2002 125 16 21 % 2026 00 203 169 2003 1164 1140% 132.67 00 1327 110.8 `2004 1216 1170% 142:30 0.0 1,423 1188 '2005 1049 11 70% 122.70 00 1227 1024 '2006 1131 1170% 13286 0.0 1324 110:5 `2007 1274 11 70% 14903 00 1490 1244 2008 1274 11.70% 149 03 00 149.0 1244 2009 1274 11.70% 14903, 00 149 0 1244 2010 1 1274 1 11'.70% 149.03 1 00 1 149 0 1244 Total 1 1,5730 71 1 1 1896:74 1 393 65 1 2290 39 1912 00 * Calculation assumes an in -place ash density of 55 Ibs per cubic foot Or NC #0004774, Page 23 of 23 December- 2003 V Estimated Total Storage Volume Required' for Term of 'Permit• Wet-Weather Detention Volume = 189 8 Acre -feet Estimated Solids: to Ash Basin = 1912 0 Acre -feet Total = 2102 0 Acre -feet VI Results. Available Water Storage Capacity based on basin, survey dated 5/24/1989' Additional Primary Cell @ Pond elevation 695' +0" ( *) 825, Acre -feet Old Pnmary'Cell @ Full Pond El 685' +6 1/4" = 1152 Acre-feet Secondary Cell @ Full Pond EI 675' +5 1/4" = 320 Acre -feet Total= F 2297 Acre -feet Required Storage Volume through 12/31/2010 = 2102 ,Acre -feet Based on these conservative calculations, there is. sufficient capacity in the ash basin to provide the retention volume specified in the permit,through the year 2010 " Design Full Pond Elevation for the Additional Primay Cell is 705' +0 ". The pond is currently managed with an administrative limit of 695' +0" Buck Steam Station Balanced'Indi%!enous Population Buck Steam Station's operating experience during the past five years under the thermal limitations imposed in,NPDES Permit No. NC #0004774 and field data collected (see attached report) substantiates the discharge from Buck Steam Station is such that the protection and propagation of a balanced indigenous aquatic community in the Yadkin River is assured. Accordingly, Duke Energy Corporation requests a,contmuation of the thermal variance for outfall 001, as allowed under NC Administrative Code 15A.NCAC 02B .0208 (b) and also section 316 (a) of the Clean Water Act. rA