NC0004979_Permit Renewal_20041122

1WDuke
Power®
A Duke Energy Company
November 22, 2004
Mr. David Goodrich
In Care of. Ms. Carolyn Bryant
NC DENR/Water Quality/NPDES Unit
512 N. Salisbury Street
Raleigh, North Carolina 27604
Subject: NPDES Permit Renewal, NC0004979
Allen Steam Station, Gaston County
Dear Mr. Goodrich,
PROCUREMENT, CONSTRUCTION AND
EH&S
Duke Power
EC11E / P.O. Box 1006
K Cha.clot ;-NC-2,8241�L44�fi�,;��
r NOV 2 3 2004
DENR - WATER QUALITY
POINT SOURCE BRANCH
The subject NPDES permit is scheduled to expire on May 31, 2005. As required 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 application for renewal, which includes the following
items:
• EPA Form 1
• EPA Form 2C
• EPA Form 2F
• Site maps
• Supplemental Information to the NPDES Application
• The Balanced Indigenous Population (BIP) Report
In review of historical monitoring data for outfall 002 many parameters have been continuously
measured at very low concentrations or below detection levels. It is therefore requested that
these parameters be either eliminated from monitoring requirements or reduced in monitoring
frequency. These parameters are as follows: Barium, BOD, Cadmium, Chromium, Copper,
Cyanide, Fecal Coliform, Naphthalene, Nickel, Phenol, Phosphorus, Sulfate and Zinc.
It is also requested that the current selenium limit is changed from a daily maximum limit to a
monthly average limit for the following reason:
40 CFR 131.36 list the Criterion Maximum Concentration (CMC) and the Criterion Continuous
Concentration (CCC) for selenium at 20 ug/l and 5 ug/1, respectively. Since the current selenium
limit of 31 ug/1 is based on the CCC value of 5 ug/1, the limit should be expressed as a monthly
average value. The Environmental Protection Agency's "Ambient Water Quality Criteria for
Selenium — 1987" document -page 34 and 40 CFR 131.36 also supports this request.
The attached BIP report shows that the balanced indigenous aquatic community in Lake Wylie is
being maintained under the current limits. Accordingly, Duke Energy Corporation requests a
continuation of the thermal limitations that are presently in the NPDES permit.
www.dukepower.com

Duke Energy is willing to meet and discuss any of the above items at your earliest convenience.
If additional inforniation is needed please contact Robert Wylie at [phone]. Your
cooperation in renewing this NPDES permit is appreciated.
Sincerely,
A-"44 A /2, -/L, -
Michael A. Ruhe
Manager, Environmental Support
cc: Mr. Rex Gleason — NCDENR, Moorseville, N.C.
Ms. Trish MacPherson — NCDENR, Raleigh, N.C. (BIP Report 3 copies)
Attachments

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Plant Allen, Gaston County
NPDES Permit No. NC0004979
Page 3 of 26
1.0 GENERAL INFORMATION
Plant Allen utilizes waters from the Catawba River for condenser cooling and service
water requirements. A brief discussion of each discharge follows. A schematic flow
diagram of water use, treatment, and discharges indicating typical (average) flow rates
for individual waste streams at Plant Allen is attached. All flows are based on historical
data where possible or pump design capacities and normal run-times.
2.0 OUTFALL INFORMATION
2.1 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
and then discharges into the South Fork River. Each of the 5 units at Plant Allen
has two condenser cooling pumps. The number of pumps used is dependent on
unit load and intake temperatures \ ith more pumps running with higher loads
and intake temperatures.
Units 1 and 2 share a common cooling water supply tunnel served by a total of 4
CCW pumps. Units 3 and 4 also share a tunnel and 4 CCW pumps. Unit 5 has
a separate tunnel and 2 CCW pumps. The common tunnel design enables three
pumps to give Units 1 and 2 or 3 and 4 the equivalent of 1 '/2 pump operation.
The 1 '/2 pumps operation adds an economical range or flexibility when units are
on partial load and when intake water temperatures are minimal.
Unit No.
1 -Pump GPM
1.5 -Pump GPM
2 -Pump GPM
1
55,500
74,800
83,500
2
55,500
74,800
83,500
3
83,000
111,200
126,000
4
83,000
111,200
126,000
5
83,000
126,000
All condenser tubes at Plant Allen are cleaned manually with metal or rubber plugs.
Mechanical cleaning is required once a year for most units. A leak test is performed
periodically on the condenser tubes. (See section 2.2.6.4.) If leaks are detected, then
one method used to temporarily stop small leaks is to add sawdust to the CCW system,
as previously approved by NCDENR. The sawdust is added at amounts that will plug the
leaks and not result in an environmental impact. This is a temporary measure until the
unit can come off-line so the leaks can be permanently repaired.
2.1.1 Asiatic Clam/Debris Filter Backwash
Water for the Unit 5 CCW water is filtered for any twigs, leaves and other light
debris, which passed through the intake screens. Asiatic clams, which are

Plant Allen, Gaston County
NPDES Permit No. NC0004979
Page 4 of 26
common in Lake Wylie and can clog the condenser tubes, are also captured in
this filter. This filter is backwashed once a week for 15 minutes. A maximum
flow of 3000 GPD is realized. No other additives are in the backwash water. The
twigs, leaves, clams and other light debris collected in the debris filter are
indigenous to the river and are therefore flushed back with no harmful
environmental consequences.
2.2 Outfall 002 -Ash Basin
2.2.1 Boiler Cleaning
All five boilers at Plant Allen are chemically cleaned with the next cleaning as
needed. The volume of the boilers determines the quantity of chemicals
required for a cleaning. Boilers #1 and #2 each have a waterside volume of
26,700 gallons. The volume of boilers #3, #4, and #5 is 40,100 gallons each.
The volume of dilute waste chemical discharged from unit #1 or #2 during a
cleaning is 294,000 gallons. The volume of diluted waste chemicals drained
from #3, #4 and #5 totals 450,00.0 gallons each. These wastes are drained
through temporary piping to the permanent ash removal lines, which flow to the
ash basin. Immediately prior to the beginning of a boiler chemical cleaning
procedure, additional stop logs are added to the ash basin discharge structure.
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).
A list of the chemicals and amounts required to clean the boilers at Plant Allen
follows:
CLEANING CHEMICALS
Sodium bromate
Ammonium carbonate
Ammonium hydroxide*
Hydrochloric acid*
Thiourea*
Citric acid
Sodium Sulfite
Ammonium bifluoride
Detergent (Triton X)
Antifoam agent
AMOUNT USED PER UNIT
Boiler #1 and #2
550 lbs
1000 lbs
850 gal
3700 gal
1680 lbs
300 lbs
100 lbs
1100 lbs
20 gal
10 gal
Boiler #3, #4 & #5
550 lbs
1000 lbs
950 gal
5500 gal
2010 lbs
400 lbs
1.00 lbs
1700 lbs
20 gal
10 gal.
During a chemical metals cleaning these chemicals are present in amounts
greater than the reportable quantity as identified under the Comprehensive
Environmental Response, Compensation, and Liability Act (CERCLA). If a spill

Plant Allen, Gaston County
i NPDES Permit No. NC0004979
Page 5 of 26
of any these chemicals were to occur, in most cases, it would be routed to the
ash basin for treatment.
2.2.2 Stormwater run-off "
Storm water run-off enters the ash basin from the from the ash basin's drainage area,
the yard drainage sump and the coal yard sump. The powerhouse sump discharges its
rainfall run-off into the yard drainage sump. A more detail description of the sump
systems and stormwater run-off is included in section 3.4.
2.2.3 Sanitary Wastes
Sanitary waste at Plant Allen is treated in a septic tank with the effluent from the
septic tank being discharged to the Ash Basin via the Coal Yard sump.
Approximately 150 people are responsible for the load on this system. An
average flow of 4850 GPD is treated by the system. The drinking water well
supplies the drinking water requirements of Plant Allen. Plant Allen is a non-
transient and non -community drinking water system. This drinking water system
is listed as ID # 01-36-704 in the NCDENR database.
2.2.4 Ash Sluice
Plant Allen utilizes electrostatic precipitators to remove fly ash from its stack
gases. These precipitators require approximately 10.0 MGD for fly ash sluicing
to the ash basin. Bottom ash sluicing to the basin requires approximately 6.0
MGD for a total average ash removal flow of 16.0 MGD..,
Plant Allen presently has additional air pollution control systems installed on
three units. Use of these systems entails the use of low concentrations of
ammonia and sulfur compounds. These systems aid in the collection of the ash
in the electrostatic precipitators.
A Selective Non -Catalytic Reduction (SNCR) system has been installed on unit
1 to aid in the reduction of NOx emissions. SNCR systems operate by injecting
urea into the upper section of the boiler where a chemical reaction occurs to
reduce the NOx to water and nitrogen. Some residual ammonia will be collected
on the fly ash in the electrostatic precipitators and a small amount will be carried
to the ash basin. However, the operation of the SNCR system is not expected to
require additional treatment capabilities to ensure compliance with NPDES
permit limits. Additional SNCR systems are to be installed on the remaining 4
units at Allen over the next several years.
2.2.5 Recirculating Water System (RCW)
Plant Allen has 2 RCW systems: a chiller system and a pump cooling water
system. Both systems use the biocide H-550 or similar products. In addition, the
corrosion inhibitor CS or similar product is used. Generally, these systems are
closed loop, but may need to be drained occasionally. All such water would
enter the floor drains and then be discharged to the ash basin.

Plant Allen, Gaston County
NPDES Permit No. NC0004979
Page 6 of 26
2.2.6 Miscellaneous Waste Streams
2.2.6.1 Turbine Non-destructive Testing
Approximately once per year, one turbine is tested for cracks in the
generator shaft using an ultrasonic nondestructive test. During the
process a maximum of 400 gal of demineralized water mixed with 4 gal of
corrosion inhibitor is used and discharged to the ash basin.
2.2.6.2 Heat Exchanger Cleaning
From time to time, it may be necessary to clean the small heat
exchangers with polyacrylamide, polyacrylate, sodium laurylsulfate and tri -
sodium phosphate. All wastes would be routed to the ash basin.
2.2.6.3 Condensate Polishers:
Plant Allen utilizes condensate polishers which divert a portion of the
normal condensate (closed system) flow through one of two cells per unit.
The polishers provide filtration as well as ion exchange functions to
remove or substantially reduce dissolved solids and suspended matter
present in the condensate stream. The polishers require precoating with
a combination of anion and cation resin. To facilitate precoating, 125-150
ml of a solution of polyacrylic acid (25%) is added to the precoat slurry.
Upon exhaustion, the precoat is removed from the filters by water / air
blasting and flushed to the ash basin via sumps. Condensate water is
used to remove the exhausted precoat at the rate of:
Unit 1 & 2 - 1558 gal/precoat
Units 3, 4, & 5 - 2090 gal/precoat.
A total average waste flow of approximately 980 GPD to the ash basin is
realized.
2.2.6.4 Condenser Leakage Testing:
Fluorescing Dye Method - Approximately 1 Ib. of a disodium fluorescing
dye added to 280,000 gals of demineralized water is used occasionally to
test the condensers for leakage. All wastes from the testing would be
routed to the ash basin.
Sulfur Hexafluoride Method - Periodically, sulfur hexafluoride is injected
into the condenser tubes to locate condenser tube leaks. Sulfur
hexafluoride is a chemically inert, nonflammable, nontoxic gas with an
extremely low water solubility. It is estimated that 150 grams of sulfur
hexafluoride would be used during the leak detection process. Most of the
sulfur hexafluoride would be volatilized during the process.

Plant Allen, Gaston County
NPDES Permit No. NC0004979
Page 7 of 26
2.2.7 Ash Basin Treatment
CO2 Injection System - During warmer periods of the year, algae blooms occur in
the ash basin causing pH levels to rise. A CO2 system is utilized during these
events to maintain the pH level below 9.0 standard units.
Acid Injection System - An acid injection system utilizing 78-80 % sulfuric acid is
maintained as back-up to the CO2 system for pH adjustment
Sodium Hydroxide System - A sodium hydroxide injection system utilizing 25% or
50% sodium hydroxide is maintained for pH adjustment.
2.2.8 Yard Drain Sump
The yard drain sump is a large concrete structure that has three level controlled
pumps, which pump wastewater from Plant Allen to the ash basin. These pumps
are operated on a rotating basis. The combined average flow from all sources tied
to the yard drain sump is approximately 4.0 MGD. (See Section 3.4 for a more
detail description of rainfall run-off entering the yard drain sump.) Below is a
description of waste streams going to the yard drain sump:
2.2.8.1 Boiler Room Sumps (Units 1-4)
The water which flows to the boiler room sumps originates from such
sources as floor wash water, boiler blowdown, water treatment waste,
condensates, equipment cooling water, sealing water and miscellaneous
leakage (refer to the attached schematic of water flow for individual flows).
The effluent from the units 1 through 4 boiler room sumps is flushed to the
yard drain sump. The effluent from the unit 5 boiler room sump is flushed
to the power house sump, which is then flushed to the yard drain sump.
2.2.8.2 Turbine Room Sumps
The turbine room sumps accommodate flows from floor washing, leakage,
and occasional condenser water box drainage. Effluent from units 1
through 5 turbine room sumps is flushed to the yard drain sump.
2.2.9 Water Treatment System
The water treatment wastes consist of sedimentation, filter backwash, reverse
osmosis (RO) concentrate, demineralizer regeneration wastes and boiler blowdown.
The make-up water treatment system is compromised of a clarifier, two pressure
filters, two activated carbon filters, two garnet filters, a reverse osmosis machine and
one set of demineralizers. Make-up water is used in the boilers and closed cooling
systems.
Clarifier:
The clarifier has an average production of 0.252 MGD. Alum and caustic or
ferric sulfate/ferric chloride are used to affect precipitation and thus remove
suspended solids from the raw river water. Desludging of the clarifier takes

Plant Allen, Gaston County
NPDES Permit No. NC0004979
Page 8 of 26
place approximately 8% of the unit run-time with an average volume of 2300
GPD going to the ash basin.
Pressure Filters:
There are two pressure filters which follow the clarifier in the water treatment
process. These filters are backwashed once per week with a waste flow of
11,000 gallons per backwash. Each pressure vessel will contain 84 ft3 of
anthracite, 50 ft3 of quartz, 25 ft3 of garnet and 41 ft3 of garnet/quartz support
media. Each vessel will use product water to backwash at a rate of 750 gpm.
On average, both vessels will backwash once per week. The contents' of the
pressure filters will be changed out, as internal maintenance requires, and the
used filter medium will be disposed of in the ash basin.
Activated Carbon Filters:
In addition to the pressure filters, there are two activated carbon filters. These
filters are backwashed twice per month. Approximately 30,000 gallons of water
are required to backwash each of these filters. The activated carbon filters are
composed of approximately 250 ft3 of granular activated carbon (coal). The
spent filter medium is changed out yearly and is disposed of in the ash basin.
RO Prefilters:
There are 2 RO prefilter vessels containing garnet, which are used to filter
suspended solids. Both filters are backwashed once per week
with the backwashed material routed to the ash basin. Total waste for both
filters is 4500 gallons per week.
RO Unit:
A RO unit is used to decrease the conductivity in the filtered water, thereby
increasing the efficiency of the demineralizers and reducing the amount of
chemical needed for demineralizer regeneration. During operation, the unit has
a continual blowdown of 60 gal/min, which is discharged, to the ash basin. The
RO unit is cleaned on a quarterly basis with the waste going to the yard drains
and eventually the ash basin. During a cleaning, approximately 30 lbs of the
cleaner OSMO AD -20 (containing sulfamic acid) along with 5 gallons of biocide,
2 liters of sodium hydroxide, and 0.5 gallons of sodium lauryl sulfate is used.
Demineralizer:
The demineralizer consists of two mixed -bed cells. Only one of these cells is
operated at any one time. The cell which is in operation is regenerated
approximately once every 7- 14 days of operation. A regeneration requires 42
gallons of sulfuric acid (78-80%) and 150 gallons of 50% sodium hydroxide. An
average dilute waste chemical and rinse flow of 20,000 gal is realized. The
dilute acid and caustic are discharged to the floor drains simultaneously through
the same header for neutralization purposes. All regeneration wastes are
flushed to the ash basin. The demineralizer resin is changed out approximately

Plant Allen, Gaston County
NPDES Permit No. NC0004979
Page 9 of 26
once every 10 years with the spent resin going to the ash basin. Approximately
1 ml of the surfactant Triton CF -54 or similar product is added to the new resin to
improve separation.
Boiler Blowdown:
Each of the five boilers at Plant Allen blowdown at an average rate of
approximately 500 lbs. of steam per hour. The blowdown is allowed to flash in a
blowdown tank. Most of the blowdown is vented to the atmosphere with a
minimal amount of condensate discharged to the boiler room sump. The
average condensate flow to this sump is 0.004 MGD. Hydrazine is maintained at
a concentration of 25 ppb in the condensate system for deoxygenation. A
minute amount of hydrazine (<10 ppb) may be present in the condensate flow to
the boiler room sump.
2.2.10 Preheater Washes
Preheaters are backwashed with raw water approximately 2 times per year to
remove ash and corrosion products. There are 12 preheaters at Allen that would
require approximately 100,000 gallons of backwash water each. The backwash
water is routed to the ash basin through the yard drain sump.
2.2.11 Laboratory Wastes
The chemistry lab on site performs a variety of water analyses and routine sample
collections. Therefore several chemicals are used in the lab in small quantities for
sample preservation, bottle rinsing, equipment calibration, conductivity analyses, _
etc. The wastes are flushed down the sink and discharged into the yard drain sump
and then pumped to the ash basin. Some of the laboratory chemicals are as
follows: Ammonia molybdate, Acetic acid, Ferric sulfate, Hydrochloric acid,
Monoethylamine, Nitric acid and Potassium hydroxide.
2.2.12 Power House Sump (Unit 5)
The wastes, which enter the floor drains at Plant Allen, accumulate in the boiler
room sumps and turbine room sumps. The water which flows to the boiler room
sumps originates from such sources as floor wash water, boiler blowdown, water
treatment waste, condensates, equipment cooling water, sealing water and
miscellaneous leakage. Effluent from the unit 5 boiler room sump is flushed to the
powerhouse sump, which is then flushed to the yard drain sump. This sump also
collects stormwater from various drains located on the north end of the powerhouse.
(See Section 3.4 for a more detail description of rainfall run-off entering the
powerhouse sump.)
2.2.13 Physical Chemical Treatment System
An Authorization to Construct permit number NC0004979A01 was issued to Allen
Steam Station on June 21, 2004 for a physical chemical treatment system that will
allow construction of:

Plant Allen, Gaston County
NPDES Permit No. NC0004979
Page 10 of 26
• three primary settling cells,
• a treatment channel,
• a chemical injection system, and
• a final settling/focculation cell.
The purpose of this system is to provide a chemical injection system for treatment of
dissolved pollutants that will not settle out of the wastestream through purely
physical means. The system will treat 18-24 MGD sluice water to reduce the TSS
and selenium to below permit limits. The three primary settling cells will be used to
settle the solids (one at a time, while the inactive cells are being cleaned).
The treatment channel will convey settled sluice water to the secondary settling or
flocculation cell. Approximately 25-50 gpm of the settled waste stream from the
treatment channel will be pumped into the chemical treatment building. This
pumped stream will provide the opportunity to take samples before and after
treatment and serve as the waste stream's chemical injection point. The chemicals
that are presently permitted for treatment in this system are: sulfuric acid, ferric
sulfate and ferric chloride.
After chemical addition and mixing in the treatment channel, the treated waste
stream will be discharged into a floc setting basin to allow sufficient settling time for
any precipitated compounds to settle prior to discharge. Overflow from the final
settling cell will flow through a vegetated ash delta prior to discharge to the main
pond. There will be an alternative route to discharge from the vegitated ash delta
directly to the final discharge tower.
2.2.14 Wastewater from Future Plant Additions
2.2.14.1 Selective Non -Catalytic Reduction (SNCR)
As part of the compliance with the North Carolina Clean Air Initiative
(NCCAIR), Allen will install an urea based "trim" Selective Non -Catalytic
Reduction (SNCR) systems on all five units. The installation has been
completed for Unit 1. The trim SNCR systems are expected to reduce
NOx emissions by approximately 30%. SNCR systems operate by
injecting urea into the upper section of the boiler where a chemical
reaction occurs to reduce the NOx to water and nitrogen. Some residual
ammonia will be collected on the fly ash in the electrostatic precipitators
and a small amount will be carried to the ash basin. However, the
operation of the SNCR system is not expected to require additional
treatment capabilities to ensure compliance with NPDES permit limits.
Two pressure filters with polymer injection will be installed to provide
make up water to the SNCR system. Each pressure filter will be
backwashed once per week with a waste flow of 5000 gallons per

Plant Allen, Gaston County
NPDES Permit No. NC0004979
Page 11 of 26
backwash. Each pressure filter will contain anthracite, quartz, garnet and
garnet/quartz support media.
2.2.14.2 Flue Gas Desulfurization (FGD)
The installation of a Wet Flue Gas Desulfurization (FGD) system is to be
installed at Allen in the future for the reduction of SO2 from the stack gas.
The following provides a description of the FGD system at Allen.
In a Wet Scrubber system the SO2 component of the flue gas produced
from the coal combustion process is removed by reaction with limestone -
water slurry. The particular system to be used at Allen will collect the flue
gas after it passes through the electrostatic precipitator and route the gas
into the absorber tank. As the gas rises through the tank to the outlet at
the top, the gas passes through a spray header. An atomized slurry of
water and limestone droplets is continually sprayed through this header
into the stream of flue gas. The SO2 in the flue gas reacts with the
calcium in the limestone and produces SO3. The SO3 slurry falls to the
bottom of the tank where a stream of air is injected to oxidize the slurry to
form gypsum (CaSO4-H2O). The gypsum slurry is drawn off the absorber
tank and subsequently to a vacuum belt filter. Part of the process water
from the FGD system is blown down in order to maintain the FGD water
chemistry within the FGD system specifications. This water will be treated
in a wastewater treatment system that will discharge to the ash basin.
The FGD system will require a material handling system that will supply
limestone to the scrubber and a gypsum storage area for the gypsum
removed from the process. The limestone will come into the site by rail. It
is then transferred to the FGD site via a covered conveyor. Runoff from
the storage area is routed to the ash basin. The gypsum is routed from
the FGD tank via a covered conveyor belt that will carry it to a storage
pile. The runoff from this area is also routed to the ash basin.
2.3 Outfall 002A — Coal Yard Sump Overflow
An overflow pipe that directs flow from the sump to the Catawba. River was included in
the construction of the coal yard sump. This was done to prevent submergence and
damage of the pump motors within the sumps in the event that.all pumps failed or
redundant power supply lines could not be restored in a timely manner. Overflow has
not occurred during the last permit cycle.
2.4 Outfall 0026 — Powerhouse Sump Overflow
An overflow pipe that directs flow from the sump to the ground was included in the
construction of the powerhouse sump. This was done to prevent submergence and
damage of the pump motors within the sumps in the event that all pumps failed or
redundant power supply lines could not be restored in a timely manner. If enough water

Plant Allen, Gaston County
NPDES Permit No. NC0004979
Page 12 of 26
overflows, the waste water could potentially get to the Catawba River. Overflow has not
occurred during the last permit cycle.
2.5 Outfall 003 — Misc Equipment Cooling & Seal Water
Outfall 003 discharges into the CCW discharge canal. The discharge consists of
cooling water from units 4 and 5 boiler feedpump hydraulic coupling coolers and other
miscellaneous equipment cooling. This water is once -through, non -contact cooling
water withdrawn from the service water system.
Approximately 10,000 gpd of bearing cooling water for the ash line booster pump is
routed back to the discharge canal via a stormwater outfall in the vicinity of outfall 003.
The water is once through, non -contact cooling water withdrawn from the service water
system. .
2.6 Outfall 004 — Equip. Cooling & Intake Screen Backwash
2.6.1 Equipment Cooling Water
Cooling water for units 1,2 & 3 boiler feed pump hydraulic coupling coolers and
other miscellaneous equipment is discharged through outfall 004. This water is
once -through, non -contact water drawn from the service water system. In
addition, water from a vehicle rinse -down area is directed to this outfall. The
rinse water contains no soaps or other additives. Allen is also adding a new
chiller system for comfort cooling that will be a once through non contact cooling
water system and will discharge back to the river via outfall 004.
2.6.2 Intake Screen Backwash
The intake screens at Plant Allen are flushed on an "as needed" basis.
Backwash usually averages 2 hours per shift. The average volume required is
0.053 MGD. The large debris floating on the river is caught on the parallel bar
screens. This trash is collected and disposed of in a landfill. The silt, twigs, .
leaves and other light debris collected on the rotating screens are indigenous to
the river and are therefore flushed back with no harmful environmental
consequences.
3.0 STORMWATER GENERAL INFORMATION
3.1 Site Description
Allen Steam Station property covers approximately 953 acres. The powerhouse,
the plant yard, the coal pile, the switchyards, and associated material and
equipment storage areas cover about 65 acres. These developed areas are
generally flat. There are approximately 5 miles of rail access and 1 2/3 miles of
paved roadways on-site. Coal is shipped to the site by rail lines. There is a 64
acre retired ash basin. The active ash basin has a surface area of about 176
acres, and it receives runoff from another 112 acres.

Plant Allen, Gaston County
NPDES Permit No. NC0004979
Page 13 of 26
Based on information from the Soil Survey of Gaston County, North Carolina, the
original site soils at Allen Steam Station were from the Gaston series. These
soils are classified as sandy clay loam with red clay in the subsoils. In developed
areas, the soil profile has been altered by grading and filling. The site
topography is generally flat with rolling hills in outlying, undeveloped areas.
3.2 Storm Water Drainage System
In developed areas, runoff flows overland to ditches and catch basins, which are
connected to a buried network of corrugated metal pipes (CMP). Rainfall runoff
from the coal pile and coal handling areas and portions of the plant yard goes to
the yard sumps that discharge to the ash basin. Storm water runoff from other
areas of the site is discharged to the Catawba River and the South Fork River.
Rainfall runoff from the transformer yard area and the 115 KV switchyard is
routed through oil trap tanks prior to being discharged.
3.3 Characterization of Drainage Basins
A description of the drainage area, significant materials, and material control
measures is presented for each drainage basin. Herbicides .are spot applied
where required in parking areas, switchyards, parts laydown areas, along
walkways, and around various fixtures and buildings.
3.4 Storm Water Outfalls
Characteristics for 14 individual outfalls and one group of outfalls are presented.
• Storm Water Outfall 1
Discharge Structure: 10 inch(") diameter (�) CMP
Location: North of station on railroad tracks
Drainage Area: 1.75 acres
Area Description
This outfall conveys runoff from an undeveloped, wooded area upland of the
railroad tracks and from the tracks themselves. About 200 feet of an unpaved
road passes through the drainage area, and there are about 1600 feet of railway
lines. There are no paved or roofed areas in this drainage area.
Significant Materials / Controls
Significant materials are not stored within this drainage basin.
Storm Water Outfall 2
Discharge Structure: 24" � CMP
Location: North of station on railroad tracks
Drainage Area: 10.6 acres

Plant Allen, Gaston County
NPDES Permit No. NC0004979
Page 14 of 26
Area Description
This outfall conveys runoff from an undeveloped, wooded area upland of the
railroad tracks and from the tracks themselves. About 600 feet of an unpaved
road passes through the drainage area, and there are about 900 feet of railway
lines. There are no paved or roofed areas in this drainage area.
Significant Materials / Controls
Significant materials are not stored within this drainage basin.
Storm Water Outfall 3
Discharge Structure: 8" � CMP
Location: North of station on railroad tracks
Drainage Area: 1.4 acres
Area Description
This outfall conveys runoff from an undeveloped, wooded area upland of the
railroad tracks and from the tracks themselves. About 50 feet of an unpaved
road passes through the drainage area, and there are about 1500 feet of railway
lines. There are no paved or roofed areas in this drainage area.
Significant Materials / Controls
Significant materials are not stored within this drainage basin.
;ischarge
Storm Water Outfall 4
Structure: 10" � Cast Iron Pipe
Location: North of station at Catawba River
Drainage Area: 1.4 acres
Area Description
This area is an extremely flat area covered with gravel that is used as a material
laydown area. None of the drainage area is paved or roofed.
Significant Materials / Controls
Laydown Area:
Spare equipment, parts, steel, iron, cable, and miscellaneous supplies
are stored in a large, flat, gravel laydown area north of the
powerhouse. The equipment and supplies generally do not contain
liquids.
;ischarge
Storm Water Outfall 5
Structure: 18" CMP
Location: North of station at Catawba River
Drainage Area: 7.4 acres

Plant Allen, Gaston County
NPDES Permit No. NC0004979
Page 15 of 26
Area Description
This outfall conveys runoff from an undeveloped, wooded area upland of the
railroad tracks and from the tracks themselves. About 450 feet of a paved road
passes through the drainage area, and there are about 2,580 feet of railway
lines. About 2 percent of this drainage area is paved.
Significant Materials / Controls
Significant materials are not stored within this drainage basin.
�ischarge
Storm Water Outfall 6
Structure: 10" � Cast Iron Pipe
Location: North of station at Catawba River
Drainage Area: 1.7 acres
Area Description
This area is an extremely flat area covered with gravel that is used as a material
laydown area. None of the drainage area is paved or roofed.
Significant Materials / Controls
Laydown Area:
Spare equipment, parts, steel, iron, cable, and miscellaneous supplies are
stored in large, flat, gravel laydown area north of the powerhouse. The
equipment and supplies generally do not contain liquids.
• Storm Water Outfall 7
Discharge Structure: 18" � CMP
Location: North of Station at Catawba River
Drainage Area: 5.5 acres
Area Description
This outfall conveys runoff from an undeveloped, wooded area upland of the
railroad tracks, from the tracks themselves, and from a laydown yard. About 400
feet of a paved road passes through the drainage area, and there are about
2,280 feet of rail lines. The laydown yard is extremely flat and covered in gravel.
About 2.5 percent of this drainage area is paved.
Significant Materials / Controls
Laydown Area:
Spare equipment, parts, steel, iron, cable, and miscellaneous supplies are
stored in a large, flat, gravel laydown area north of the powerhouse. The
equipment and supplies generally do not contain liquids.

Plant Allen, Gaston County
NPDES Permit No. NC0004979
Page 16 of 26.
;ischarge
Storm Water Outfall 8
Structure: 24" � CMP
Location: North of Station at Catawba River
Drainage Area: 5.0 acres
Area Description
This outfall conveys runoff from the hill North of the powerhouse including
undeveloped wooded areas, from the gravel parking areas at the outage trailer
area, and the grassed areas around the fuel oil tank. This outfall also conveys
runoff from a segment of railroad tracks and from the laydown area adjacent to
the north warehouse. There are approximately 1,000 feet of paved roadways
and 2,400 of railroad tracks in this drainage basin. About 2 percent of this
drainage area is paved or roofed. The fuel oil tank is not located within this
basin because it is surrounded by an earthen berm, and drainage from inside the
berm is routed to the powerhouse yard sump.
Significant Materials /Controls
Parking:
There is a gravel parking area at the outage trailers. This lot is used
occasionally during outages.
Laydown Area:
Spare equipment, parts, steel, iron, cable, and miscellaneous supplies are
stored in a large flat, gravel laydown area adjacent to the north field
warehouse. The equipment and supplies generally do not contain liquids.
;ischarge
Storm Water Outfall 9
Structure: 3' Concrete Ditch
Location: North of Intake Structure at Catawba River
Drainage Area: 0.5 acres
Area Description
This outfall conveys drainage from a segment of railroad tracks in front of the
powerhouse and. from the grassy embankment between the tracks and the
intake structure. About 920 feet of railroad tracks pass through this area. There
are no paved or roofed areas in this basin.
Significant Materials / Controls
Significant materials are not stored within this drainage basin.
;ischarge
Storm Water Outfall 10
Structure: 24" � CMP
Location: South of Intake Structure at Catawba River
Drainage Area: 0.9 acres

Plant Allen, Gaston County
NPDES Permit No. NC0004979
Page 17 of 26
Area Description
This outfall conveys runoff from a segment of the railroad tracks in front of the
powerhouse and from the grassy embankment between the tracks and the
intake structure. About 1,280 feet of railroad tracks pass through this area.
There are no paved or roofed areas in this basin. Drainage from the CCW clam
filter pit is discharged through this outfall.
Significant Materials / Controls
Significant materials are not stored within this drainage basin.
Storm Water Outfall 111 NPDES Outfall 004
Discharge Structure: 72" � CMP
Location: East of Coal Pile at Catawba River
Control Structure: 65,300 gallon oil trap tank
Drainage Area: 14.2 acres
Area Description
This drainage area comprises most of the southern end of the station yard, and
most of this area is developed. This outfall conveys roof drainage from a portion
of the powerhouse roof, the machine shop roof, the service building roof, the
warehouse roof, and some of the coal handling buildings. These roofed areas
cover about 1.3 acres. Two large paved parking lots cover 3 acres. Other
parking and paved areas cover about 1 acre. About 3,100 feet of rail lines pass
through this drainage area, but only half of them are used regularly. Runoff from
a portion of the transformer yard area and from the entire 115 kV switchyard is
routed to a 65,300 gallon oil trap tank prior to being discharged to this outfall.
The switchyard is covered with gravel. Other portions of the drainage area
include the powerhouse yard, grassy, and undeveloped areas. About 50 percent
of this drainage area is roofed or paved. NPDES discharges including
miscellaneous non -contact cooling water from plant equipment, vehicle wash
water, and intake screen backwash water are conveyed through this outfall.
Significant Materials / Controls
Coal: Coal dust may be present around coal handling areas.
Kerosene: There is a 200 -gallon aboveground, carbon steel kerosene tank in
front of the service building.
Parking: There are about 3.2 acres of paved parking areas within this drainage
basin.

Plant Allen, Gaston County
NPDES Permit No. NC0004979
Page 18 of 26
Laydown Area:
Spare equipment, parts, steel, iron, cable, and miscellaneous supplies are
stored in a flat, concrete laydown yard adjacent to the warehouse. The
equipment and supplies generally do not contain liquids.
Gasoline: There is a 500 -gallon aboveground, carbon steel gasoline tent tank
across from the warehouse. The tank is completely enclosed within a
steel tent enclosure, and any leaks would be self contained. The
enclosure can be drained by opening a valve, and that valve remains
closed at any other time. Any fluid drained from the tent is captured and
not released to SW Outfall 11. The tank is filled by a 1,500 gallon tanker
truck. Clean up supplies are located nearby. Gasoline contaminated
groundwater from recovery wells is sometimes stored in a 55 -gallon drum
beside the gasoline tank.
Oil: Runoff from the 115 kV switchyard and from a portion of the station's
main transformer yard is routed to the south oil trap tank which has a
capacity of 65,300 gallons. The south oil trap tank discharges storm
water to SW Outfall 11. Transformers 1A, 1T1, CT1, 2T1, 2A, and 3T1
contain a total of 34,533 gallons of mineral oil. The largest volume
contained by a single transformer is 9,715 gallons. The oil circuit
breakers in the 115 kV switchyard contain a total of 73,229 gallons of
mineral oil. Each circuit breaker has three tanks, and each tank contains
either 933 or 1,070 gallons of mineral oil, depending on the model. Two
transformers at the switchgear house each contain 196 gallons of mineral
oil
Storm Water Outfall 12 / NPDES 003
Discharge Structure: 36" � CMP
Location: Discharge Canal
Control Structure: 100,000 gallon oil trap tank
Drainage Area: 11.1
Area Description
This drainage area includes portions of the powerhouse yard north and west of
the station and part of the hill to the north of the station where the outage trailers
are located. This drainage basin includes a portion of the station main
transformer yard and the 230 kV switchyard. Within the powerhouse yard, the
drainage basin is flat and generally covered with gravel or grass. About 1,400
feet of rail lines pass through this drainage area, but they are not used regularly.
Less than 5 percent of this drainage area is roofed or paved. Runoff from the
powerhouse yard immediately north and west of the station is routed to a
100,000 gallon oil trap tank prior to being discharged to this outfall. Runoff from
the transformer yard goes to the oil trap tank. Runoff from the 230 kV switchyard
is not routed to the north oil trap tank because the switchgear in the 230 kV

Plant Allen, Gaston County
NPDES Permit No. NC0004979
Page 19 of 26
switchyard is gas cooled and does not contain oil. NPDES discharges of
miscellaneous non -contact cooling water are routed through the north oil trap
tank and then discharged by this outfall.
Significant Materials / Controls
Ash: Ash pipelines run through this area carrying ash from the plant to the ash
basins..
Parking: There are gravel parking areas at the outage trailers. These lots are
used occasionally during outages.
Oil: Runoff from a portion of the station's main transformer yard is routed to
the north oil trap tank. The trap tank discharges storm water to SW
Outfall 12. Transformers 3T2, 3A, 4T1, 4A, 4T2, 5T1, 5T2, 5A, CT2, and
6A contain a total of 73,158 gallons of mineral oil. The largest volume
contained by a single transformer is 13,790 gallons. The switchgear in
the 230 kV switchyard does not contain oil. The north oil trap tank has a
capacity of 100,000 gallons.
;ischarge
Storm Water Outfall Group 13
Structure: Fourteen 10" � CMP's
Location: Every 200 feet along the railroad tracks west of retired ash
basin
Drainage Area: 10.2 acres
Area Description
These outfalls are located every 200 feet along the railroad tracks in front of the
retired ash basin. These outfalls convey runoff from the railroad tracks and from
the ash basin embankment. About 7,500 feet of railroad tracks pass through this
drainage area. None of this drainage area is paved or roofed.
Significant Materials / Controls
Significant materials are not stored within this drainage basin.
• Storm Water Outfall 14
Discharge Structure: 21" � CMP
Location: Catawba River between the coal pile and retired ash basin
Drainage Area: 6.0 acres
Area Description
This outfall conveys surface drainage from the area between the embankment at
the retired ash basin and the coal pile. None of the drainage area is paved or
roofed.

Plant Allen, Gaston County
NPDES Permit No. NC0004979
Page 20 of 26
Significant Materials / Controls
Significant materials are not stored within this drainage basin.
;ischarge
Storm Water Outfall 15
Structure: 36" � Reinforced Concrete Pipe
Location: Catawba River at retired ash basin
Drainage Area: 65 acres
Area Description
This is the discharge structure from the retired ash basin. This outfall conveys
only surface drainage from the retired ash basin. None of this drainage area is
paved or roofed.
Significant Materials / Controls
Significant materials are not stored within this drainage basin.
2.2 Sump System
At Allen Steam Station, there are three yard sumps: the powerhouse yard sump,
the yard drainage sump, and the coal yard sump. The powerhouse yard sump is
located east of the powerhouse, at the north end. The powerhouse yard sump
discharges to the yard drainage sump. The yard drainage sump is located east
of the coal pile and adjacent to the coal yard sump. The yard drainage sump
and coal yard sump discharge to the ash basin.
�ocation:
Powerhouse Yard Sump
East of the powerhouse, at the north end
Drainage Area: 4.0 acres
Area Description
Industrial wastewater from some of the powerhouse sumps flows to the
powerhouse yard sump. Storm water runoff from a portion of the powerhouse
roof, the plant yard, the fuel oil unloading area, and the bulk fuel oil tank area
drains to the powerhouse yard sump. The portion of the powerhouse roof that
drains to the powerhouse sump is about 2.2 acres. About 85 percent of this
drainage basin is paved or roofed. Overflow from the powerhouse yard sump
would spill to the ground and then flow overland and could eventually reach the
Catawba River. Overflow from the powerhouse yard sump is permitted as
NPDES Outfall 0026. Overflow from the powerhouse yard sump is not a normal
occurrence.
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 total tank capacity is 100,000 gallons. There is a catch
basin inside the berm. This outlet has a valve which is normally closed.

Plant Allen, Gaston County
NPDES Permit No. NC0004979
Page 21 of 26.
The storm water is inspected for the presence of oil, and if it is clean, it
can be drained if there is significant standing water.
In the fuel oil unloading area, fuel is transferred from an 8;000 gallon
tanker truck to the bulk storage tank via pipelines. DOT unloading
procedures are followed. The fuel oil unloading area is paved and
surrounded by a one foot concrete curb and ramps to contain any spills.
There is a small sump to drain rainfall; the sump has a valve which is
normally closed. Spill clean-up supplies are located nearby. Piping from
the unloading area to the bulk fuel oil tank is aboveground or enclosed in
a concrete trench.
The 48 transformers for the Units 1-5 precipitators contain a total of 7,560
gallons of mineral oil. About 3/5 of the precipitator transformers are
located within this drainage area. The maximum oil content of any single
component is 205 gallons.
Wastewater:
Plant wastewater from equipment discharges, floor drains, sumps, etc.
is routed to the powerhouse yard sump. This wastewater may include
oil, chemical, and hazardous waste spills.
• Yard Drainage Sump
Location: East of the coal pile
Drainage Area: 4.0 acres
Area Description
The powerhouse yard sump discharges to the yard drainage sump. The yard
drainage sump discharges to the ash basin. In addition to the discharge from
the powerhouse yard sump, the yard drainage sump receives industrial
wastewater from some of the powerhouse sumps. Industrial wastewater
includes effluent from the turbine room sumps and boiler room sumps. Storm
water runoff from a portion of the plant yard and parts of coal handling drains to
the yard drainage sump. The total roofed area in this basin is about 1.5 acres
including the warehouse roof, the maintenance garage roof, and a portion of the
powerhouse roof. About half of this drainage basin is paved or roofed.
Approximately 1,300 feet of railroad tracks pass through this drainage area.
Overflow from the yard drainage sump would discharge to the coal yard sump.
Overflow from the sump is not a normal occurrence.
Significant Materials / Controls
Oil: Used oil is stored in a 4,500 gallon steel tank. The tank is surrounded by
a steel containment dike about five feet tall, and the piping is surrounded
by a 6 -inch concrete curb. Rainfall that accumulates inside the dike can
be drained by opening a valve that drains to the ash trench which leads to

Plant Allen, Gaston County
NPDES Permit No. NC0004979
Page 22 of 26
the yard drainage sump. When the used oil tank is full, the product is
removed from site by tanker truck.
Small quantities of used oil are initially poured into 55 -gallons drums. The
drums are stored in the used oil staging area under cover, adjacent to the
warehouse, for temporary storage. When the drums are full, they are
emptied into the used oil tank. Empty oil drums are stored outside,
adjacent to the boat shed.
Approximately 250 gallons of oil are stored inside the maintenance garage
where floor drains flow to the yard drainage sump.
The 48 transformers for the Units 1-5 precipitators contain a total of 7,560
gallons of mineral oil. About 2/5 of the precipitator transformers are
located within this drainage area. The maximum oil content of any single
component is 205 gallons. Two transformers associated with the
wastewater and coal yard sumps each contain 270 gallons of mineral oil.
Fuel oil dispensers for the locomotives and bulldozers are located
adjacent to the maintenance garage.
Wastewater: Plant wastewater from equipment discharges, floor drains, sumps,
etc. is routed to the yard drainage sump. This wastewater may include
oil, chemical, and hazardous waste spills.
Coal: Coal dust is present along the railroad tracks and coal handling areas.
Ash: Ash pipelines run through this drainage area.
Chemicals:
There is a 5,000 gallon tank of sulfuric acid located adjacent to the
warehouse. The tank is surrounded by a concrete dike with an outlet
to the ash line trench which leads to the yard drainage sump. Drums
of various chemicals are stored inside a covered, locked shed adjacent
to the warehouse.
Hazardous Waste / Satellite Accumulation Areas:
There is a satellite accumulation area for paint, chemicals, solvents,
cleaners, etc. adjacent to the paint warehouse. Hazardous wastes are
stored in a covered area adjacent to the maintenance garage.
Laydown Area:
There is a large laydown area adjacent to the warehouse. The area is
paved and fenced. Spare equipment and parts are stored in the
laydown area.

Plant Allen, Gaston County
NPDES Permit No. NC0004979
Page 23 of 26
See description for powerhouse yard sump for additional significant materials.
�ocation:
Coal Yard Sump
East of the coal pile
Drainage Area: 25.0 acres
Area Description
Storm water runoff from the coal piles and from parts of coal handling drains to
the coal yard sump. Less than one percent of this drainage basin is paved or
roofed. Approximately 800 feet of railroad tracks pass through this drainage
area. Overflow from the coal yard sump would be conveyed to the Catawba
River. Overflow from the coal yard sump is permitted as NPDES Outfall 2a.
Overflow from the sump is not a normal occurrence.
Significant Materials / Controls
Oil: Two transformers associated with the wastewater and coal yard sumps
each contain 270 gallons of mineral oil.
A fuel oil dispenser for the bulldozers is located in the northwest corner
of the smaller coal pile.
Coal: Runoff from the coal pile and some coal handling areas is routed to
the coal yard sump.
Wastewater:
Effluent from the septic system goes to coal yard sump.
3.5 Similarity of Storm Water Outfalls at Allen Steam Station
Monitoring all of the storm water outfalls at Allen Steam Station should not be necessary
since many of the outfalls convey storm water from areas of substantially identical
activities and materials. Storm water outfalls 8 and 15 are representative for the entire
site.
4.0 Hazardous and Toxic Substances
4.1 Hazardous and Toxic Substances Table 2c- 3
At Plant Allen, the potential for toxic and hazardous substances being
discharged 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 discharge are as follows:
Acetaldehyde, Asbestos, Butyl Acetate, Cyclohexane, Diuron, Epichlorohydrin,
Formaldehyde, Monoethyl Amine, Propylene Oxide, Pyrethrins, Vinyl Acetate,
and Xylene.
Other - 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. It is not anticipated that these products will

Plant Allen, Gaston County
NPDES Permit No. NC0004979
Page 24 of 26
impact the ash basin's capacity to comply with its toxicity limits, since their
concentrations are extremely low.
4.2 40 CFR 117 and CERCLA Hazardous Substances
The following table 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
provided under 40 CFR 117 and the Comprehensive Environmental Response
Compensation and Liability Act (CERCLA). These values below represent the
maximum quantities on-site that could be released at one time and sent to the
ash basin. They do not reflect quantities that are discharged through typical use.
Allen Steam Station Hazardous Substances in Excess of RQ
Table 4.2
SUBSTANCE
QUANTITY
SOURCE
Benzene
83 lbs
Gasoline Tank
Eth (benzene
2,737 lbs
Diesel Fuel Tanks
Hydrazine
4991bs
Warehouse
Naphthalene
41,700 lbs
Fuel Oil Tanks
Sodium Hydroxide
1,181 lbs
Ash basin/Warehouse/#3 Fan Room
Sodium Nitrite
800 lbs
Warehouse/Powerhouse
Sulfuric acid
44,277 lbs
Powerhouse
Xylene (Mixed Isomers)
419 lbs
Gas Tank
5.0 Allen Steam Station 316 Determination
5.1 Allen Steam Station 316(a) determination
Duke Power Company's 316(a) demonstration (March 1976) concluded that the
"heated discharge from Plant Allen is such that the protection and propagation of
a balanced indigenous aquatic community in and on Lake Wylie is assured."
Duke's operation experience during the past five years under the thermal
limitations imposed in NPDES Permit No. NC0004979 substantiates the above
conclusion and further supports Duke's belief that the operating characteristics of
the station have a minimal effect of the aquatic environment of Lake Wylie.
Surveys of the aquatic community in Lake Wylie demonstrate that a Balanced
Indigenous Population exists in Lake Wylie. Accordingly, Duke requests a
316(a) variance and further requests that the thermal limitations imposed in the
permit be continued.

�. Plant Allen, Gaston County
NPDES Permit No. NC0004979
Page 25 of 26
5.2 Allen Steam Station 316(b) Determination
In conjunction with the rulemaking process for the new Phase II 316(b) rule
pertaining to fish impingement and entrainment, historical data and permitting
records were reviewed. Initial 316(a) and 316(b) studies associated with
enactment of the Clean Water Act concluded that the location, construction
capacity, and design of the cooling water intake of Allen and other Duke Power
steam stations were not detrimental to the aquatic ecosystem and minimize
adverse environmental impacts. Both North Carolina and EPA regulators
concurred in 1976 that 316(b) fish impingement and entrainment studies were no
longer needed at that time. Although the new Phase II 316(b) rule for existing
facilities is currently being litigated, plans for information collection (PICs) are
being developed to conduct a Comprehensive Demonstration Study (CDS) to
determine required measures to be implemented per approval of NCDENR.

Plant Allen Water Schematic
Condenser Outfall 001
Cooling 626.3 MGD
Water
Sanitary
Waste
Coal Handling
Sumps
Ash Sluice
Water
Treatment
Boiler Rm
Sumps
Intake screen n,(
Backwash
4
Atm
Boiler
PowerhouseSump
Turbine Rm
Sumps
Misc Equip
Cooling & Seals
Plant Allen, Gaston County
NPDES Permit No. NCOOO4971
Page 26 of 26
`South Fork
River
_________________ Outfall 002A -------------- 0- Catawba
River
Coal Yard Stormwater
Sump
.i
Ash Basin Outfall 002
-` 20.7 MGD River River
Yard Drainage I Slonnwater
Sump 7i I
t
Outfall 003-
4.5 MGD jo joSouth Fork
River
Catawba
_______ Outfall 002B _______________________* River
Outfall 004 Catawba
6.5 MGD 10 River
AsialicClam/ Debris 0.003 MGD Catawba
Filter River
Backwash
j

imap:Hsergei. chemikov%40 dwq. [e-mail]:143/...
Subject: permit reviews
From: [e-mail]
Date: Thu, 28 Sep 2006 08:43:48 -0400
To: sergei.chernikov@ncmail'.net
I have no comments on:
permit mod for NC0003433 - Cape Fear Steam
permit issuance for NCO038377 - Mayo Electric
permit issuance for NC0004979 - Allen Steam
Karrie-Jo Robinson -Shell, P.E.
1 of 1 9/28/2006 9:00 AM

•
•
O ®� W A T QG
y =A
J NCDENR
Michael F. Easley
Governor
William G. Ross, Jr., Secretary
North Carolina Department of Environment and Natural Resources
CI Alan W. Klimek, P.E., Director
Division of Water Quality
January 9, 2005
Mr. Michael A. Ruhe
Manager, Environmental Support
Duke Power
EC11E/P.O. Box 1006
Charlotte, North Carolina 28201-1006
Subject: Extension of deadline for Submitting
Information to Comply with the Phase II 316 (b)
Rule
Dear Mr. Ruhe:
The Division of Water Quality has reviewed your request to extend the deadline for
submitting information required by the Phase II Rule, 40 CFR Part 125 Subpart J until
January 7, 2008 for the following facilities:
1) NC0004979 Allen Steam Station
2) NC0004987 Marshall Steam Station
3) NCO024392 McGuire Nuclear Station
4) NC0004961 Riverbend Steam Stattion
5) NCO024406 Belews Creek Steam Station
6) NC0003468 Dan River Steam Station
7) NC0005088 Cliffside Steam Station
8) NC0004774 Buck Steam Stattion
After considering complexity of the issue and reviewing options allowed by the rule,
the Division grants your request. The Division encourages you to collect all the
necessary information and submit required documentation as expeditiously as
practicable and continue consultation with our staff to achieve compliance with the
requirements of the Phase 11 316 (b) rule.
If you have any questions concerning this issue, please contact Sergei Chernikov at
telephone number [phone], extension 594.
cc. Central Files
NPDES Permit File
EPA, Region N
N. C. Division of Water Quality / NPDES Unit
1617 Mail Service Center, Raleigh, NC 27699-1617
Internet: h2o.enr.state.nc.us
Sincerely,
/)--�an Klimek, P.
Phone: [phone]
fax: [phone]
DENR Customer Service Center: 1800 623-7748

Re: Buck SS question
Subject: Re: Buck SS question
From: "Robert R Wylie" <[e-mail]>
Date: Fri, 16 Jan 2004 08:01:39 -0500
To: "Mark McIntire <mark.mcintire" <[e-mail]>
Hi Mark,
Buck will not have scrubbers. That is a good idea to minimize the
addition of a permit modification. Thanks. The plants that are going to
have scrubbers are our larger fossil stations (Marshall, Belews Creek,
Cliffside and Allen).
Robert
Mark McIntire
<mark.mcintire@nc To: Robert R Wylie
<[e-mail]>
mail.net> cc:
Subject: Buck SS question
01/15/2004 11:42
ON
Robert,
I was looking over our permit assignments coming up and thought of a
question for you. I'll be working with one of our new engineers on the
Buck renewal. Is that facility going to be installing the FGD scrubber
and if so, will we be able to incorporate the permit mod (similar to
Marshall's) during the renewal process?
Thanks,
mark
1 of 1 3/23/2004 7:42 AM

WAT �Rp�
� r
October 28, 2003
Mr. Michael A. Ruhe, Manager
Environmental Support
Duke Power Company
EC11E
526 South Church Street
Charlotte, N.C. 28202-1802
Michael F. Easley, Governor
William G. Ross, Jr., Secretary
Department of Environment and Natural Resources
Alan W. Klimek, P.E. Director
Division of Water Quality
Coleen Sullins, Deputy Director
Division of Water Quality
NOV 3 2003 L)
Subject: Pilot Study Extension Request
Selenium Reduction
Allen Steam Plant
NPDES Permit No. NC0004979
Gaston County
Dear Mr. Ruhe:
This Office is in receipt of your letter dated October 27, 2003 concerning a request to
extend the on-going pilot study, which was designed to reduce the selenium concentration in the
wastewater discharged from Duke's Allen Steam Station. Selenium concentrations in the effluent
have been found to exceed the NPDES permit daily maximum limitation of 31 ug/L. The pilot
study involved the rerouting of wastewater flow in the existing ash basin through a vegetated area
of the basin where selenium concentrations have been found to be within permit compliance.
Ferric sulfate was also added to enhance the precipitation of the selenium as it passed through the
vegetated area. The rerouting of the existing waste stream and the addition of the ferric sulfate was
expected to reduce effluent selenium concentrations to below your current NPDES permit limit.
Based on preliminary results from the study, Duke has been able to maintain compliance
with the current NPDES limit. However, per your October 27th letter, continued addition of the
ferric sulfate is going to be necessary as long as high alkaline coal is your predominant fuel source.
In your letter, you requested that the pilot study be extended for up to one year, while the design of
a permitted treatment system is completed by Duke's staff, and modification of the subject permit is
completed by the Division's NPDES Unit.
Based on this Office's review of your request, we have no objection to extending the on-
going pilot study, however, six months should be ample time in which to prepare the necessary
plans and specifications and obtain the appropriate approvals from the Division. The results from
your current study should have provided you with the information needed to prepare the design for
your proposed treatment system and permit modification.. For this reason, the approval of this pilot
study extension request is only effective from the date of this letter through April 30, 2004. Please
note that under no circumstances should this approval be construed as authorization for Duke
Power to exceed any existing NPDES permit limitation or to by-pass any existing wastewater
treatment process.
NCDEN�
Customer Service
1 877 623-6748
Division of Water Quality 919 North Main Street Mooresville, NC 28115 Phone [phone]
Fax [phone]

Mr. Michael A. Ruhe
October 28, 2003
Page Two
If you have any questions regarding this matter, please contact Mr. Michael Parker or
me at 704-663-1699.
Sincerely,
D. Rex Gleason, P.E.
Water Quality Regional Supervisor
Cc: Dave Goodrich
Kevin Bowden
/mlp
hlgenlpilotstdy 102803.doc

O� W A TFR Michael F. Easley, Governor
(� William G. Ross, Jr., Secretary
�o G Department of Environment and Natural Resources
7
Alan W. Klimek, P.E. Director
'1 Division of Water Quality
Coleen Sullins, Deputy Director
Division of Water Quality
Mr. Michael A. Ruhe, Manager
Environmental Support
Duke Power Company
EC11E
526 South Church Street
Charlotte, N.C. 28202-1802
Subject
Dear Mr. Ruhe:
October 6, 2003
WEUNDS 14.011 GROUP
OCT 13 2003
WATER QUAY',` SECTION
Pilot Study Extension Request
Selenium Reduction
Allen Steam Plant
NPDES Permit No. NC0004979
Gaston County
This Office is in receipt of your letter dated September 24, 2003 concerning a request to
extend the on-going pilot study, which was designed to reduce the selenium concentration in the
wastewater discharged from Duke's Allen Steam Station. Selenium concentrations in the effluent
have been found to exceed the NPDES permit daily maximum limitation of 31 ug/L. The pilot
study involved the rerouting of wastewater flow in the existing ash basin through a vegetated area
of the basin where selenium concentrations have been found to be within permit compliance.
Ferric sulfate was also added to enhance the precipitation of the selenium as it passed through the
vegetated area. The rerouting of the existing waste stream and the addition of the ferric sulfate was
expected to reduce effluent selenium concentrations to below your current NPDES permit limit.
Based on preliminary results from the study, Duke has been able to maintain compliance
with the current NPDES limit. However, per your phone conversation with Mr. Michael Parker
with this Office on September 24, 2003, further testing for potential long-term system design and
capability is necessary. In your letter, you requested that the pilot study be extended through
October 30, 2003.
Based on this Office's review of your request, we have no objection to the 30 -day extension
of the on-going pilot study. This approval is effective from the date of this letter through October
30, 2003. Should this pilot study system prove to have positive benefits to your treatment
capability, a modification to the subject permit will be necessary if you decide to incorporate the
components of this system into your present treatment technology. Please note that under no
circumstances should this approval be construed as authorization for Duke Power to exceed any
existing NPDES permit limitation or to by-pass any existing wastewater treatment process.
A
NCDENR
Customer Service
1 877 623-6748
Division of Water Quality 919 North Main Street Mooresville, NC 28115 Phone [phone] -
Fax [phone]

Mr. Michael A. Ruhe
October 2, 2003
Page Two
i
If you have any questions regarding this matter, please contact Mr. Michael Parker or'
me at 704-663-1699.
Sincerely,
D. Rex Gleason, P.E.
Water Quality Regional Supervisor
Cc: Dave Goodrich
Kevin Bowden
/mlp
h\gen\pilotstdy.doc