NC0004774_ Permit Application_20110228

' Duke
' Energy,,
February 28, 2011
Ms. Charles H. Weaver, Jr.
State of North Carolina
Department of Environment and Natural Resources
Division of Water Quality
NPDES Unit
1617 Mail Service Center
Raleigh, North Carolina 27699 -1617
CORPORATE EHS SERVICES
Duke Energy
526 South Church St.
Charlotte, NC 28202
Mailing Address:
EC13K / PO Box 1006
Charlotte, NC 28201 -1006
Subject: Duke Energy Carolinas LLC — NPDES Permit Application
Buck Steam Station - #NC0004774
Dear Mr. Weaver:
Duke Energy Carolinas, LLC requests the subject permit be renewed and reissued.
The above referenced permit expires August 31, 2011. As mandated by North
Carolina Administrative Code 15A NCAC 2H.0105 (e), this permit application for
renewal is being submitted at least 180 days prior to expiration of the current
permit.
Please find enclosed in triplicate, the renewal application, which includes the
following items:
EPA Form 1
EPA Form 2C
Site Maps
Water Flow Diagram
Supplemental Information
Duke Energy Carolinas, LLC requests notification that this application is complete.
Additionally, the attached report, "Assessment of Balanced and Indigenous
Populations in the Yadkin River," continues to indicate recovery of aquatic
populations and includes a request to approve recommended monitoring program
modifications going forward. Therefore, this report also supports renewal of the
current thermal monitoring requirements of outfall #001.
www. duke - energy. com

Thefollowing monitoring reductions at outfall #002 are requested based on
historical monitoring data
• Total Suspended Solids from monthly to quarterly
• Total Nitrogen from monthly to quarterly
• Total Phosphorous, from monthly to quarterly
Please note that based on discussions between Duke, Energy Carolinas, LLC and
DWQ in 2006, Buck Steam Station was issued a, minor permit modification on
August 9, 2006 (see attached). This modification was inadvertently omitted when
the- NPDES permit was reissued in June,2008 Duke Energy Carolinas, LLC
requests that the referenced permit modification language be incorporated into the
new permit
Thank you in advance for your assistance on this matter Should you have
questions regarding this application, please contact metiat (704) 382 -4309
Sincerely,
� e
Allen Stowe
Water Management
Attachments
cc w/. Mr Robert Krebs - NCDENR Mooresville'R O
Mr Jimmie Overton — NCDENR, Raleigh, N C (BIP Report 3 copies)

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NOTES:
1) USGS 7.5 Minute Series Topographic Quadrangles: Salisbury and Southmont (NC) DISCHARGE LOCATION MAP FIGURE
[Source: ftp: //ftp.nconemap.com /outgoing /raster /drg/] NPDES Permit No: NC0004774
• Indicates approximate location of home assumed to be supplied by private drinking DUKE ENERGY
water well. [Source: Rowan County GIS Aerial (2006)] BUCK STEAM STATION /
Drawn By: Chad Hearn SCALE 1555 DUKEVILLE ROAD
Project Manager. Bill Miller SALISBURY, NORTH CAROLINA 28146
Client: Duke Energy o0 0,125 M;les
Date: 02/21/2011

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NC #0004774, Page 2 of 18
February 2011
General Information
Buck Steam'Station (BSS) consists of four coal -fired steam electric generating units, three natural
gas /fuel oil -fired simple cycle, combustion turbine, units, and one 2 x 1 configuration, natural gas -fired
combined cycle combustion turbine unit. Coal' fired units 3 & 4 are scheduled to retire in,May 2011.
The combined cycle unit is slated to begin full operation in October 2011. 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.
I. Outfall 001 - Condenser 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 coal -fired operating units has
two condenser cooling pumps which have the following capacities:
Unit 1
Retired
Unit 2
Retired
Unit 3
1 pump - 48;000 GPM
Unit 4
1 pump - 25,000 GPM
Unit 5
1 pump - 55,000 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;0,00 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. If this
situation occurs, a portion of the warm condenser cooling flow can be diverted back to the intake to melt
the ice. However, this activity is,done on a very limited basis. The maximum flow is 42,000 gpm.
When the units are operating, this warm discharge is immediately pulled back into the plant through the
CCW system. Condenser cleaning is accomplished mechanically After the condenser is drained, loose

NC #0004774, Page 3 of 18
February 2011
solid 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
approximately two times per year per unit.
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 (microbiocid'es and corrosion inhibitors) in order to prevent
biofouling and system corrosion. The primary corrosion inhibitor used in this- system is sodium nitrite.
The RCW and chiller systems are required to be cleaned periodically. A dispersant, wetting agent-and
detergent are typically used
II. Outfall 002 - Ash Basin
Coal Station & Simple Cycle Combustion Turbines
0 Make -Up Water Process Wastes
The water treatment wastes at BSS are made up of sedimentation, filter backwash, demineralizer
regeneration wastes and boiler blow down. The make -up water treatment system is comprised of a
clarifier, gravity filter, activated carbon filters, a demineralizer with two,cells, and a polisher
demineralizer. 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 augmentAhe facility water treatment capacity.
Vendors will use traditional water treatment methods. The following provides more specific
information on the process water treatment system:
Clarifier-
The clarifier utilizes a continuous feed of ferric sulfate, sodium hydroxide, and chlorine. The
solids in the clarifier are desludged as needed to the floor drains and then pumped to the ash
basin. BSS may alter this process to,suppl'y site clarified water by other traditional water
treatment methods and chemicals other than those identified above.

NC #0004774, Page 4 of 18
February 2011
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 day 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 ofanthracite coal., f
Activated Carbon Filters:
Two�activated carbon fitters remove organics and the chlorine that is injected in the clarifier.
These filters are backwashed approximately once per week. The wash water is discharged to the
floor drains, which flow to the unit 3 and 4 pump room sump. Approximately 140 ft3 of
activated carbon is replaced,as needed. This spent carbon, sluiced to the ash basin with bottom
ash.
Demineralizers:
Each of the two mixed, bed ionic exchange demineralizer cells has a capacity of 160 gpm, but <is
normally operated at 120 gpm. On the average, one cell is regenerated once per month A
regeneration demands 20 gallons of 93% sulfuric acid and 80 gallons of 50% 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 once every two years each demineralizer bed is brine treated. This
process uses approximately 2,000 lbs. 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 efflueint, flows to the unit 5 and 6 pump room sump A single
anion/cation bed deminerlizer is also used'.
M
Boiler Blotivdown:
Water wall and continuous blowdowns, as well as superheater drain lines from boilers 8 and'9
(units 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 liquid in the tank collectively

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1 4
1
NC #0004774, Page 5 of 18
February 2011
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 injected,into the condensate system as an oxygen,scavenger Most of the1ydrazine
is utilized and converted to ammonia and water, which is used for pH control; however, trace
amounts of hydrazine (< 10 ppb) may be found in the boiler blowdowns.
i 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 requited, then approximately,- 266,000 ,gallons of water and
chemicals are used per boiler for each chemical cleaning job. Listed below are the chemicals and
amounts (subject to change) presently used at BSS per cleaning
0
1st Stage
Chemical
Ammonium Biflouride
Ammonium Bicarbonate
Citric Acid
Copper Complexer
Hydrochloric Acid, 200 Be' (31.5 %)
Sodium Sulfite
Corrosion Inhibitors
2ND Stage
Chemicals
Ammonium Hydroxide, 260 Be'
Sodium Bromate
Sodium Carbonate
0
Amount used per Unit
1,000 lbs.
1 „000 lbs.
200 lbs.
1,620 lbs
3,300 gals.
100 lbs.
(as necessary)
Amount used per Unit
850 gals.
550 lbs.
2,000 lbs.
The waste solution is discharged to the ash basin along with the normal ash sluicing Immediately 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 ,action assures longer retention time of the chemical

0 1
NC #0004774, Page 6 of 18
February 2011
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.
o 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 not warranted any additional treatment by the ash basin in order to comply with the
pH limits
6 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 ofdomestic 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.

NC #0004774, Page 7 of 18
February 2011
• FI'oor Drains
The floor drains in the powerhouse connect to sumps where they are pumped to the ash basin. These
drains can receive inputs 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 - routine basis, as necessary for maintenance, to the
sump and pumped to the ash basin.
Non - Contact Cooling Water
Once'through non - contact cooling water from powerhouse air compressors, discharge into the
plant's sump system. This wastewater ultimately discharges into the ash basin.
Laboratory Wastes
The chemistry lab on site performs a variety of water analyses and routine sample collection.
Several chemicals are used in the lab in small quantities, for sample preservation, bottle rinsing,
equipment calibration, etc. The chemical wastes are poured down the sink, discharged into the
package sewage treatment system and then pumped to the ash basin.

NC #0004774, Page 8 of 18
February 2011'
Dredge Material:
Because silt settles in front of the plant intakes, dredging is performed as necessary to remove
sediment at the intake. In order to monitor the discharge of the return water from the dredging
activity, dredge material may be pumped to the ash basin for additional treatment.
Groundwater Remediation
A total product, recovery system has been installed at BSS' in order to remediate groundwater due
to a previous oilleak from an underground storage tank. Approval of an Authorization to
Construct'(ATC) was granted on February 10,, 1997. A maximum of 2`0 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
ultrasonic non - destructive test. During the process, one hundred gallons of demineralized 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 injection system is available for use prior to the 002 discharge to maintain the pH level
below ,9.0 standard units. Acid and /or caustic, addition may be warranted to properly adjust the
pH prior to discharge. Ferric sulfate or other, coagulants may also be used.
X Ray Process Wastewater
Periodically welds may need to be x -rayed as part of a quality assurance process. The process
used to develop the x -rays creates a small wastewater stream. Once generated, the wastewater
stream is characterized and disposed of accordingly. This wastewater is sometimes treated in the
ash basin.
De -Icing Products
In order to prevent accidents due to ice on site roads and sidewalks, de -icing products are used as
needed per the manufacturers recommendations. The run -off from this application either goes to
the Yadkin River via a storm drain or the ash basin discharge.

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NC #0004774,'Page 9 of 18
February,2011
Combined Cycle Plant
Buck Combined Cycle Addendum to the Buck NPDES Application
This portion represents a brief description of the associated water treatment systems at the combined
cycle portion of the Buck site This area is currently under construction,at the time of application. Exact
,details of all of the chemicals to be used are not available at this time. Therefore, categories of
chemicals are listed. Full commercial operations for,this portion of the Buck site are scheduled for
'October 2011. The start up and associated NPDES discharges from the Combined Cycle system testing
and commissioning, operations could begin as early as July of-201 I
Regulatory notifications will be made, to the state for biocide use 90 days prior'to anticipated discharge.
Service Water
Influent
Make up water from the Yadkin River is sent through 3 raw water, pumps to a Graver clarifier.
pH is adjusted with caustic. Coagulant, polymer and sodium> hypochlorite are also added
Sludge is removed via sludge pumps and sent through ,a thickener where more polymer is added.
Ultimately, the sludge is sent to a plate and frame filter press for dewatering and then to a
permitted landfill for disposal.
Water from the clarifier is further treated by the gravity filters and sodium hypochlorite is added
for biological control The filtered water'is stored in the Fire Water /Service'Water Tank. This
filtered water feeds the plant fire main and supplies the service water pumps.
Boiler Make-Up Water / Condensate
Boiler make up water is fed from the Fire /Service Water Tank (300,000 gallon tank) and sent through
the Reverse Osmosis (RO)'systern to the demineralizer cells. An anti - scalant and pH control is added to
the make -up boiler feedwater.
The auxiliary boiler feed water is treated with ammonia and an oxygen .scavenger. Sodium bisulf to is
also injected to remove any residual chlorine at the RO inlet.

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,NC #0004774, Page 10 of 1'8
February 2011
Citric acid & sodium hypochlorite is used in the Ultra Filtration (UF) system, Citric acid is used in the
RO system to remove scale and mineral deposits Anti - scalant is added to RO inlet to reduce scale
formation.
Boiler water /condensate is further treated at the Heat Recovery Steam Generator'(HRSG) with the
addition -of phosphates to protect from corrosion and ammonia for pH control.
Condenser Cooling Water
Condenser Cooling Water (CCW) is supplied through filtered water,sent to the ten cell cooling tower.
This water is recirculated and cycled with approximately 5% make up added hourly to account for blow
down and evaporation loss. CCW water is treated'with a dispersant corrosion inhibitor, sodium
hypochlorite and a non oxidizing biocide.
Cooling tower blow down is treated with sodium bisulfite for residual chlorine removal prior to the
water being sent to the waste water sump. Effluent from the wastewater sump is piped to the primary
ash basin
The CCW pumps circulate 94,000 gpm. There are 2 CCW pumps installed on this system. The cooling
tower blow down rate• averages 816 gpm.
The maximum capacity of the cooling tower is approximately 197,500 ft' or 1,477,620 gallons. At the
normal water level, the capacity is 151,600 ft' or 1,,133,870 gallons.
Chiller Cooling Towers
The four inlet-air chillers will have cooling water that is treated with a dispersant corrosion inhibitor,
sodium hypochlorite and a non oxidizing biocide. Blow down water will be sent to the 2 chiller sumps.
Ultimately the chiller tower blow down water is pumped to the cooling tower basin.
RRSG and Auxiliary Boiler Blow Down
All blow down from the HRS'G drains, auxiliary. boiler, demineralizer water treatment and the boiler
blow down tank are routed to the boiler blow down sump. This sump discharges to the cooling tower
basin.

NC #0004774, Page 11 of 18
February 2011
Closed Loop Cooling System
The closed loop cooling system blow down from the heat exchangers is also routed to the cooling tower
basin.
Sanitary Waste System
Sanitary waste is routed through the lift station and pumped to a package plant. This unit includes a
chlorination chamber ('sodium hypochlorite tablets). Effluent is ultimately pumped to the waste Water
sump.
Plant Drainage System
All yard and floor drains from the generation equipment areas and auxiliary systems are routed to a
common drain system and through an Oil Water Separator (OWS). The OWS discharges to the
wastewater collection sump.
Drains from the water - treatment building area, fire protection system, sanitary waste system, condenser
circulating system and cooling tower blow down are, routed to a wastewater collection sump. This
effluent is pumped to the primary ash basin.
Containments for all transformers, they ammonia tank and unloading area are routed to the storm drain
system.
Drains from the cooling tower chemical feed sumps and unloading, areas are also routed to the plant
drain system.
r

e '
NC #0004774, Page 12 of 18
February 2011
BUCK CTCC Chemical and Tank
Information
Feed
Condensate /Feed water /Boiler Rate
HRSG11 Phosphate 300 gal tank 0 - 250 gpd
HRSG12 Phosphate 300 gal tank 0 -250 gpd
0.- 25
Aqueous Ammonia 300,gal tote gpd
Auxiliary Boiler
Closed Cooling
Biocide
Glycol
Filtered Water Svstem
Sodium Hypochlorte
Clarifier,Polymer
Thickener Polymer
Coagulant
Caustic
Pot feeder in loop - manual dosage - monthly
Pot feeder in loop - manual dosage - monthly
6000agal tank
300 gal tote
300 gal tote
19000 gal tank
Tank size and d
0 - 576 gpd
0 -24
gpd
0 - 108,gpd
0 - 576,gpd
aily,feed undetermined
L
0 -05`
Aqueous Ammonia
300 gal tote
gpd
0 -05
Oxygem Scavenger
300 gal tote
gpd
Cooling Tower
0 -50
Dispersant /Corrosion Inhibitor
2000 gal tank
gpd
Sodium Hypochlonte
6000 gal tank
0 -- 500'gpd
Non - Oxidizing Biocide
300 gal tote
0­500 gpd
Sodium Bisulfite
300 gal tote
0 - 3 gpd
Cooling Tower Chiller A/B
Dispersant /Corrosion Inhibitor
2000 gal tank
0 - 5 gpd
Chemical feed tank is shared with Cooling Tower
0 -20
Sodium Hypochlonte
6000 gal tank
gpd
Chemical feed tank is shared with Cooling Tower
0 -50
Non - Oxidizing Biocide
300 gal tote
gpd
Chemical feed tote is shared with Cooling Tower
Corrosion Inhibitor
300 gal tote
0 - 1 gpd
Closed Cooling
Biocide
Glycol
Filtered Water Svstem
Sodium Hypochlorte
Clarifier,Polymer
Thickener Polymer
Coagulant
Caustic
Pot feeder in loop - manual dosage - monthly
Pot feeder in loop - manual dosage - monthly
6000agal tank
300 gal tote
300 gal tote
19000 gal tank
Tank size and d
0 - 576 gpd
0 -24
gpd
0 - 108,gpd
0 - 576,gpd
aily,feed undetermined
L

III. Outfall 002A — Yard Sump Overflow
IV
An overflow pipe that directs flow from the sump to the Yadkin River was included in the construction
ofthe yard sump This modification was done to prevent submergence and damage of the sump pump
motors i "n the event of pump failure or power outages.
IV. Outfall 003 Water
This outfall has been eliminated.
V. Outfall 004 - 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.
•
NC #0004774, Page 13 of 18
February 2011
OF /RO /Demin
6
0 -48
Citric,Acid
300 gal tote
gpd
0 -48
Sodium Hypochlorte
300,gal tote
gpd
0 -16
Antiscalant
300 gal tote
gpd
0 -16
'Caustic
300-gal tote
gpd
0 -16
Sodium Bisulfite
300gal tote
gpd
Chemical feed tote is shared with Cooling Tower
SCR
Aqueous Ammonia
20000`gal tank
Sanitary Wastewater Package
Plant
Sodium Hypochlonte
Tablets
Refill as needed
III. Outfall 002A — Yard Sump Overflow
IV
An overflow pipe that directs flow from the sump to the Yadkin River was included in the construction
ofthe yard sump This modification was done to prevent submergence and damage of the sump pump
motors i "n the event of pump failure or power outages.
IV. Outfall 003 Water
This outfall has been eliminated.
V. Outfall 004 - 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 14 of 18
February 2011
VI. Discharge 005 - Miscellaneous 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 fans
• Unwatering pumps
All of the above cooling water discharges to the BSS's intake for a total combined average flow of 4.1
MGD.
VII. Table 2c -3 Hazardous and Toxic Substances
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 in 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:
Others
NC, #0004774, Page 15 of 18
February 2011
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 be at very low concentrations.
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 -1 Thus any
discharge of'these products to the ash basin will be at very low concentrations.
VIII. 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.
Hazardous Substance Table
Substance Quantity Obs.)
Source
Hydrazine, 1,026 Boiler Room
Sodium Hydroxide 50,000 Caustic Tank
Sulfuric Acid 60,000 Acid Tank

0
NC #0004774, Page 16 of'18
February 2011
IX. Ash Basin Capacity
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
NP-DES Permit NC0064774)'
I. Estimate Runoff to the Ash Basin from a 10 -yr 24 -hr storm
1. Natural Drainage Area of Ash Basin
New Primary Cell 1`73.0
Old Primary Cell 152.0
Secondary Cell 470
Station Yard Drainage Area Pumped to Ash Basin 270
Total = 3990
2 Precipitation from 10 -yr 24 -hr storm= 5.1
3 Total Stormwater Runoff to Ash Basin = 169 58
(Assuming 100% runoff)
II Estimated Maximum 24 7hr Dry Weather Waste Stream Discharging to Ash Basin-
1. Maximum recorded Ash Basin'Discharge = 6,000,000
i
2. Increase maximum daily disharge by 10% for
conservatism,and convert units to acre-feet = 2025
III. Wet Weather Detention Volume
Sum of Parts I and II. = 189.83
IV Estimated Quantity of Solid's (Ash) to be discharged to Ash Basin through December 34, 2016.

{ P1
NC #0004774, Page 17 of 18
February 2011
Time Period
Actual or
Estimated Coal
Consumption
(1000's,tons)
% Ash
Estimated
Ash
Production
(1000's tons)
Estimated
Ash
Production
(Ac -ft)
('Sept -Dec) 2005
6010
1560%
406
33 89
2006
17485
14.80%
112
93 50
2007
18930
13.20%
1056
88.15
2008
14470
1,2.80%
779
65.03
2009
3880
13.00%
27.3
2279
2010
7039 0
1250%
3670
3064
2011
4006.0
9,60%
15 30
1277
2012
10000
9.60%
3 80
3 17
2013
10860
960%
420
3 51
2014
19250
9.60%
7.40
6.18
2015
0.0
0.00%,
000
'000
2016
0.0
000%
0.00
0.00
Total
801700
30.70
359.63
I
* Calculation assumes an in -place ash density of 55 lbs per cubic -foot
r
V Estimated Total Storage Volume Required through 2016•
Wet Weather Detention Volume =
Estimated Solids to Ash Basin Sept 2005 - Dec.,2016 =
Total =
VI Results
Additional Primary Cell
2009 Ash Basin Cleanout
Old Primary Cell
Secondary Cell
Total
Note Available Storage based on basin survey dated. 8 /25%2005
u
189 8
Acre -feet
359 6
Acre -feet
5495
Acre -feet
207.4 Acre -feet
806 Acre -feet
1705 Acre -feet
1211 Acre -feet
5796 Acre -feet
Required Storage Volume Through 12/31/2016: 549 5 Acre -feet

,• a i"
NC #0004774, Page 18 of 18
February 2011
Based on these calculations, there is sufficient capacity in the ash basin to provide the
retention volume, specified in`the permit through'the year 2016.
X. Buck Steam Station Balanced Indigenous Population
Buck Steam Station's operating experience, 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 Carolinas, LLC requests a continuation of
the thermal variance for otitfall 001, as allowed under NC Administrative Code 15A NCAC 02B .0208
(b) and also section 316 (a) of the Clean Water Act.
Duke Energy Carolinas, LLC 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.