NC0004979_Issuance (Permit)_20180713 (2)

ROY COOPER
Governor
MICHAEL S. REGAN
Secretary
LINDA CULPEPPER
interim Director
NORTH CAROLINA
Environmental Quality
July 13, 2018
Mr. Paul Draovitch, Senior Vice President
Environmental, Health and Safety
Duke Energy Carolinas, LLC
Mail Code EC 13K
P.O. Box 1006
Charlotte, North Carolina 28201-1006
Dear Mr. Draovitch:
REC,FI ED
JUL 2 6 2018
CEN'Tt'<AL FILES
°'VR SECT10i1;
Subject: Issuance of NPDES Permit
Permit NC0004979
Allen Steam Station
Gaston County
Facility Class I
The Division of Water Resources is forwarding herewith the Final NPDES Permit for Allen
Steam Station. This permit modification is issued pursuant to the requirements of North
Carolina General Statute 143-215.1 and the Memorandum of Agreement between North
Carolina and the U.S. Environmental Protection Agency dated October 15, 2007 (or as
subsequently amended).
A public hearing was held on April 8, 2015 in Lincolnton seeking comments on the Draft
permit. This Final permit incorporates recommendations of the DWR Hearing Officer and
EPA as well as other changes:
• The monitoring frequency for As, Se, Hg, and Ag were reduced to weekly from monthly
(Outfall 002 - normal operation/decanting).
• The downstream monitoring location was relocated closer to the ash pond discharge;
the sampling will be conducted 250 meters below Outfall 002.
• The schedule to submit documentation required for 316(b) was reduced to 3.5 years.
• The compliance date for the bottom ash transport water and FGD wastewater was
changed to February 28, 2020.
• The new requirement for the decanting and dewatering stages was added to the permit.
The facility shall immediately discontinue the discharge and report to the DEQ if the
identified pollutants of concern reach 85% of the allowable level.
• The requirement to select a new cold water reference area for the next 316(a) study was
added to the permit.
• The instream monitoring frequency was increased to monthly from semi-annually.
North Carolina Department of Environmental Quality I Division of Water Resources
512 North Salisbury Street 11611 Mail Service Center I Raleigh, North Carolina 27699-1611
919.707.9000

If any parts, measurement frequencies, or sampling requirements contained in this permit are
unacceptable to you, you have the right to an adjudicatory hearing upon written request within
thirty (30) days following receipt of this letter. This request must be in the form of a written
petition, conforming to Chapter 150B of the North Carolina General Statutes, and filed with the
office of Administrative Hearings, 6714 Mail Service Center, Raleigh, North Carolina 27699-6714.
Unless such a demand is made, this permit shall be final and binding.
Please note that this permit is not transferable except after notice to the Division. The Division
may require modification or revocation and reissuance of the permit. This permit does not affect
the legal requirements to obtain other permits which may be required by the Division of Water
Resources or any other Federal, State, or Local governmental permits that may be required.
If you have any questions on this permit, please contact Sergei Chernikov at 919-807-6386.
Sincerely,
l
Lin a Culpepper, Interim Director
Division of Water Resources
Hardcopy: Central Files,
NPDES Files
Mooresville Regional Office, Water Quality
E-copy: US EPA, Region IV
WSS/Aquatic Toxicology Branch
PERCS
e:!.e,f 0-- 1E Q�
North Carolina Department of Environmental Quality I Division of Water Resources
512 North Salisbury Street 11611 Mail Service Center I Raleigh, North Carolina 27699-1611
919.707.9000

Permit NC0004979
STATE OF NORTH CAROLINA
DEPARTMENT OF ENVIRONMENTAL QUALITY
DIVISION OF WATER RESOURCES
PERMIT
TO DISCHARGE WASTEWATER UNDER THE
NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM
In compliance with the provision of North Carolina General Statute 143-215.1, other lawful standards and
regulations promulgated and adopted by the North Carolina Environmental Management Commission, and the
Federal Water Pollution Control Act, as amended,
Duke Energy Carolinas, LLC
is hereby authorized to discharge wastewater from a facility located at the
Allen Steam Station
253 Plant Allen Road (NCSR 2525)
Belmont
Gaston County
to receiving waters designated as the Catawba River (Lake Wylie), unnamed tributary to the Catawba River, and
South Fork Catawba River in the Catawba River Basin in accordance with effluent limitations, monitoring
requirements, and other applicable conditions set forth in Parts I, II, and III.
This permit shall become effective August 1, 2018.
This permit and authorization to discharge shall expire at midnight on July 31, 2023.
Signed this day July 13, 2018.
Linda pepper, Interim Director
Division of Water Resources
By Authority of the Environmental Management Commission
Page 1 of 25

Permit NC0004979
SUPPLEMENT TO PERMIT COVER SHEET
All previous NPDES Permits issued to this facility, whether for operation or discharge are hereby revoked. As of
this permit issuance, any previously issued permit bearing this number is no longer effective. Therefore, the
exclusive authority to operate and discharge from this facility arises under the permit conditions, requirements,
terms, and provisions included herein.
Duke Energy Carolinas, LLC is hereby authorized to:
1. Continue to discharge:
• Outfall 001: once through cooling water.
• Outfall 002: Ash Basin discharge. This outfall includes domestic wastewater, stormwater from the
coal pile area, miscellaneous stormwater flows, ash sluice, wastewater from turbine non-destructive
testing, landfill leachate, FGD blowdown, yard drain sump, water treatment filter backwash, treated
groundwater, laboratory wastes, and the power house sump at Unit 5. The domestic waste is pre-
treated by a septic tank. Outfall 002 wastewater is treated using chemical coagulation, settling, and
pH neutralization. Outfall 002 and Outfall 006 might be operational at the same time during the
transitionperiod.
• Outfall 002A: coal yard sump overflow (discharge from coal handling and storage areas).
• Outfall 002B: power house sump overflow (floor wash water, boiler blowdown, water treatment
waste, condensates, equipment cooling water, sealing water and miscellaneous leakage).
• Outfall 003: miscellaneous equipment non -contact cooling and sealing water.
• Outfall 004: miscellaneous non -contact cooling water, vehicle washwater, and intake screen
backwash.
• Outfall 006: Upon completion of construction of the Retention Basin, discharge domestic
wastewater, stormwater from the coal pile area, miscellaneous stormwater flows, ash sluice,
wastewater from turbine non-destructive testing, landfill leachate, FGD blowdown, yard drain
sump, water treatment filter backwash, treated groundwater, laboratory wastes, and the power
house sump at Unit 5. The domestic waste is pre-treated by a septic tank. Outfall 006 wastewater
is treated using chemical coagulation, settling, and pH neutralization. Outfall 002 and Outfall 006
might be operational at the same time during the transition period.
• Outfall 007: the emergency spillway of the new Retention Basin. The spillway is designed for a
flood greater than 100-year event. Sampling of this spillway is waived due to unsafe conditions
associated with sampling during an overflow event.
• Outfall 008: the emergency spillway of the retired Ash Pond. The spillway is designed for a flood
greater than 100-pear event. Sampling of this spillway is waived due to unsafe conditions associated
with sampling during an overflow event.
• Toe Drain Outfalls 103 Oat. - 35010.512'; long.-8100.360�, 104 Oat. - 35010.541'; long. - 8100.364�,
108 oat. - 35010.710'; long - 8100.384�, and 108B Oat. - 35010.689'; long - 8100.391�: 4 potentially
contaminated toe drains.
From a facility located at the Plant Allen Steam Station on Plant Allen Road (NCSR 2525), south of
Belmont in Gaston County, and
2. Without adding detergents or chemicals of any kind, discharge Asiatic clam/debris filter backwash from the
intake filter screen, in accordance with condition A. (10.), and
3. Continue to operate a Flue Gas Desulfurization (FGD) wet scrubber wastewater treatment system
discharging to the Ash Basin through Internal Outfall 005; consisting of:
• A flow equalization tank and a maintenance tank
• Feed systems for lime, sulfide, iron addition, polymer, hydrochloric acid, and nutrient addition
• Two clarifiers
• Dual heat exchangers
• Selenium reduction bioreactors
Page 2 of 25

Permit NC0004979
• A sludge treatment system including three filter presses; and
4. Discharge from said treatment works at the location specified on the attached map into the Catawba River
classified as WS-IV B (outfalls 002, 002A, 002B, 004, 006, 008, 103, 108, and 108B), the unnamed tributary
to Catawba River classified as WS-IV B (Outfall 104), and the South Fork Catawba River classified as WS-V
(outfalls 001 and 003), in the Catawba River Basin.
Page 3 of 25

Permit NC0004979
Part I
A. (1.) EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS (Outfall 001)
[15A NCAC 02B .0400 et seq., 02B .0500 et seq.]
During the period beginning on the effective date of this permit and lasting until expiration, the Permittee is
authorized to discharge from outfall 001- Condenser Cooling Water (CCW). Such discharges shall be limited and
monitoredz by the Permittee as specified below:
EFFLUENT
LIMITS
MONITORING REQUIREMENTS
CHARACTERISTICS
Monthly
Daily
Measurement
Sample Type
Sample Location
Average
Max.
Frequency
Flow, MGD
Daily
Pump Logs
Effluent
Temperature
une 1 — September 30 1
38.9 °C
102 -
Dail y
Grab or
Instantaneous
Effluent
Temperature
October 1 — May 31 i
35 OC
95 OF
Drily
Grab or
Instantaneous
Effluent
Notes:
1. Based upon studies conducted by the permittee and submitted to the Division, it has been determined pursuant
to Section 316(a) of the Clean Water Act that the thermal component of the discharge assures the protection
and propagation of a balanced, indigenous population of shellfish, fish and wildlife in the receiving water body.
2. The permittee shall submit Discharge Monitoring Reports electronically using NC DWR's eDMR application
system. Please See Special Condition A. (26.).
Chlorination of the once through condenser cooling water, discharged through outfall 001, is not allowed
under this permit. Should Duke Energy Carolinas, LLC wish to chlorinate its condenser cooling water, a
permit modification must be obtained beforehand.
Page 4 of 25

Permit NC0004979
A. (2.) EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS (Outfall 002-normal
operation/ decanting)
[15A NCAC 02B .0400 et seq., 02B .0500 et seq.]
During the period beginning on the effective date of this permit and lasting until expiration, the Permittee is
authorized to discharge from outfall 002 — ash pond effluent (decanting the free water above the settled ash
layer that does not involve mechanical disturbance of the ash). Such discharges shall be limited and
monitored4 b�- the Permittee as specified below:
EFFLUENT
CHARACTERISTICS
LIMITS
MONITORING
REQUIREMENTS
Monthly
Average
Daily
Maximum
Measurement
Fre uen
Sample Type
Sample
Location
Flow, MGD
Weekly
Instantaneous
or Estimate
Influent or
Effluent
Oil and Grease
15.0 mg/L
20.0 mg/L
Monthly
Grab
Effluent
Total Suspended Sohds8
30.0 mg/L
50.0 mg/L
Monthly
Grab
Effluent
Total Copper 1
1.0 mg/L
1.0 mg/L
Monthly
Grab
Effluent
Total Iron 1
1.0 mg/L
1.0 mg/L
Monthly
Grab
Effluent
BOD, 5-dap, 20' C6
30.0 mg/L
45.0 mg/L
Monthly
Grab
Effluent
Fecal Coliform (geo. mean) 6
200/100 mL
400/100 mL
Monthly
Grab
Effluent
Total Selenium , µg/L
Weekly
Grab
Effluent
Total Arsenic, µg/L
Weekly
Grab
Effluent
Total Silver
0.255 µg/L
1.081 µg/L
Weekly
Grab
Effluent
Total Nickel, µg/L
Monthly
Grab
Effluent
Total Lead, µg/L
Monthly
Grab
Effluent
Total Mercury 2, ng/L
Weekly
Grab
Effluent
Total Nitrogen
102 + NO3 + TKN , m L
Quarterly
Grab
Effluent
Total Phosphorus, mg/L
Quarterly
Grab
Effluent
Chronic Toxicity 3
Quarterly
Grab
Effluent
Total Hardness, mg/L
Monthly
Grab
Effluent
Turbidity5, NTU
Monthly
Grab
Effluent
Bromide, mg/L
Monthly
Grab
Effluent
pH7
Between 6.0 and 9.0 standard
units
Monthly
Grab
Effluent
Footnotes:
1. The limits for total copper and total iron only apply when chemical metal cleaning wastewaters are being
discharged.
2. Mercury shall be measured using EPA Method 1631E.
3. Whole Effluent Toxicity shall be monitored by chronic toxicity (Ceriodaphnia) P/F at 23.6%, see Special
Condition A. (17).
4. The permittee shall submit Discharge Monitoring Reports electronically using NC DVWs eDMR application
system. Please See Special Condition A. (26.).
Page 5 of 25

Permit NC0004979
5. The discharge from this facility shall not cause turbidity in the receiving stream to exceed 50 NTU. If the
instream turbidity exceeds 50 NTU due to natural background conditions, the discharge cannot cause turbidity
to increase in the receiving stream. Therefore, if the effluent measurement exceeds 50 NTU, the Permittee shall
sample upstream and downstream turbidity in the receiving waterbody, within 24 hours, to demonstrate the
existing turbidity level in the receiving waterbody was not increased. All data shall be reported on the DMRs.
(See 15A NCAC 2B .0211 (21)). NTU - Nephelometric Turbidity Unit.
6. The limit and monitoring apply only when the domestic wastewater is being discharged to the basin.
7. The facility shall continuously monitor pH when the decanting process commences (and the pump is operating)
and the decanting pump shall be shutoff automatically when the 15 minutes running average pH falls below 6.1
standard units or rises above 8.9 standard units. Pumping will be allowed to continue if interruption might result
in a dam failure or damage. The continuous pH monitoring is only required when the pumps are employed for
decanting.
8. The facility shall continuously monitor TSS concentration when the decanting process commences (and the
pump is operating) and the decanting pump shall be shutoff automatically when one half of the Daily Maximum
limit (15 minutes average) is exceeded. Pumping will be allowed to continue if interruption might result in a dam
failure or damage. The continuous TSS monitoring is only required when the pumps are employed for
decanting.
There shall be no discharge of floating solids or visible foam in other than trace amounts.
If any one of the pollutants (As, Se, Hg, Ni, and Pb) reaches 85% of the allowable level during the
decanting/dewatering, the facility shall immediately discontinue discharge of the wastewater and report it
to the Regional Office and Complex NPDES Permitting Branch via telephone and e-mail.
The facility is allowed to drawdown the wastewater in the ash pond to no less than three feet above the
ash. The rate for lowering the liquid level in a coal ash pond shall not exceed one (1) foot per day unless a
higher rate is supported to the satisfaction of DEMLR and in accordance with NCAC, Title 15A,
Subchapter 2K.
The facility shall use a floating pump suction pipe with free water skimmed from the basin surface using
an adjustable weir.
Lowering the level below the three feet mark triggers the limits and conditions in Section A. (3.) of the
permit.
By November 1, 2018 there shall be no discharge of pollutants in fly ash transport water. This requirement
only applies to fly ash transport water generated after November 1, 2018.
By February 28, 2020 there shall be no discharge of pollutants in bottom ash transport water. This
requirement only applies to bottom ash transport water generated after December 31, 2023.
In accordance with the N.C.G.S. § 130A-309.210, by December 31, 2019, the facility shall convert to the
disposal of dry bottom ash, as defined in the Coal Ash Management Act ("CAMA").
The facility shall notify via e-mail DWR Complex NPDES Permitting Unit and DWR Mooresville
Regional Office, in writing, seven calendar days prior to the commencement of the decanting.
When the facility commences the ash pond/ponds decanting, the facility shall treat the wastewater
discharged from the ash pond/ponds using physical -chemical treatment, if necessary, to assure state
Water Quality Standards are not contravened in the receiving stream. Duke Energy shall notify DWR
NPDES Permitting and DWR Mooresville Regional Office, in writing, within seven calendar days of
installing additional physical -chemical treatment at this Outfall.
Page 6 of 25

Permit NC0004979
A. (3.) EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS (Outfall 002-dewatering)
[15A NCAC 02B .0400 et seq., 02B .0500 et seq.]
During the period beginning on the commencement of dewatering and lasting until expiration, the Permittee is
authorized to discharge from outfall 002 — ash pond effluent (dewatering-removing the interstitial water).
Such discharges shall be limited and monitored4 by the Permittee as specified below:
EFFLUENT
CHARACTERISTICS
LIMITS
MONITORING REQUIREMENTS
Monthly
Average
Daily
Maximum
Measurement
Frequency
Sample Type
Sample
Location
Flow, MGD
1.09
Daily
Instantaneous
or Estimate
Influent or
Effluent
Oil and Grease
15.0 mg/L
20.0 mg/L
Weekly
Grab
Effluent
Total Suspended Solids6
30.0 mg/L
50.0 mg/L
Weekly
Grab
Effluent
Total Copper 1
1.0 mg/L
1.0 mg/L
Weekly
Grab
Effluent
Total Iron 1
1.0 mg/L
1.0 mg/L
Weekly
Grab
Effluent
BOD, 5-day, 20' C 7
30.0 mg/L
45.0 mg/L
Weekly
Grab
Effluent
Fecal Coliform (geo. mean) 7
200/100 mL
400/100 mL
Weekly
Grab
Effluent
Total Selenium, µg/L
Weekly
Grab
Effluent
Total Arsenic, µg/L
Weekly
Grab
Effluent
Total Silver
3.74 µg/L
15.13 µg/L
Weekly
Grab
Effluent
Total Mercury Z, ng/L
Weekly
Grab
Effluent
Total Nitrogen
Oz+NO3+ /L
Weekly
Grab
Effluent
Total Phosphorus, mg/L
Weekly
Grab
Effluent
Chronic Toxicity 3
Monthly
Grab
Effluent
Total Hardness, mg/L
Weekly
Grab
Effluent
Turbidity5, NTU
Weekly
Grab
Effluent
Bromide, mg/L
Weekly
Grab
Effluent
Total Chromium, µg/L
Weekly
Grab
Effluent
Total Lead, µg/L
Weekly
Grab
Effluent
Total Nickel, µg/L
Weekly
Grab
Effluent
Total Cadmium, µg/L
Weekly
Grab
Effluent
Total Zinc, µg/L
Weekly
Grab
Effluent
TDS, mg/L
Weekly
Grab
Effluent
pH$
Between 6.0 and 9.0 standard
units
Weekly
Grab
Effluent
Footnotes:
1. The limits for total copper and total iron only apply when chemical metal cleaning wastewaters are being
discharged.
2. Mercury shall be measured using EPA Method 1631E.
3. Whole Effluent Toxicity shall be monitored by chronic toxicity (Ceriodaphnia) P/F at 1.6%, see Special
Condition A. (17.).
Page 7 of 25

Permit NC0004979
4. The permittee shall submit Discharge Monitoring Reports electronically using NC DWR's eDMR
application system. Please See Special Condition A. (26.).
5. The discharge from this facility shall not cause turbidity in the receiving stream to exceed 50 NTU. If the
instream turbidity exceeds 50 NTU due to natural background conditions, the discharge cannot cause turbidity
to increase in the receiving stream. Therefore, if the effluent measurement exceeds 50 NTU, the Permittee shall
sample upstream and downstream turbidity in the receiving waterbody, within 24 hours, to demonstrate the
existing turbidity level in the receiving waterbody was not increased. All data shall be reported on the DMRs.
(See 15A NCAC 2B .0211 (21)). NTU - Nephelometric Turbidity Unit.
6. The facility shall continuously monitor TSS concentration when the dewatering process commences (and the
pump is operating) and the dewatering pump shall be shutoff automatically when one half of the Daily
Maximum limit (15 minutes average) is exceeded. Pumping will be allowed to continue if interruption might
result in a dam failure or damage. The continuous TSS monitoring is only required when the pumps are
employed for dewatering.
7. The limit and monitoring apply only when the domestic wastewater is being discharged to the basin.
8. The facility shall continuously monitor pH when the dewatering process commences (and the pump is
operating) and the dewatering pump shall be shutoff automatically when the 15 minutes running average pH
falls below 6.1 standard units or rises above 8.9 standard units. Pumping will be allowed to continue if
interruption might result in a dam failure or damage. The continuous pH monitoring is only required when the
pumps are employed for dewatering.
9. The limit applies only when pumping is used for dewatering.
There shall be no discharge of floating solids or visible foam in other than trace amounts.
If any one of the pollutants (As, Se, Hg, Ni, and Pb) reaches 85% of the allowable level during the
decanting/dewatering, the facility shall immediately discontinue discharge of the wastewater and report it
to the Regional Office and Complex NPDES Permitting Branch via telephone and e-mail.
The rate for lowering the liquid level in a coal ash pond shall not exceed one (1) foot per day unless a
higher rate is supported to the satisfaction of DEMLR and in accordance with NCAC, Title 15A,
Subchapter 2K.
The facility shall use a floating pump suction pipe with free water skimmed from the basin surface using
an adjustable weir.
By November 1, 2018 there shall be no discharge of pollutants in fly ash transport water. This requirement
only applies to fly ash transport water generated after November 1, 2018.
By February 28, 2020 there shall be no discharge of pollutants in bottom ash transport water. This
requirement only applies to bottom ash transport water generated after December 31, 2023.
In accordance with the N.C.G.S. § 130A-309.210, by December 31, 2019, the facility shall convert to the
disposal of dry bottom ash, as defined in the Coal Ash Management Act ("CAMA").
The facility shall notify DWR Complex NPDES Permitting Unit and DWR Mooresville Regional Office
seven calendar days, in writing, prior to the commencement of the dewatering.
When the facility commences the ash pond/ponds dewatering, the facility shall treat the wastewater
discharged from the ash pond/ponds using physical -chemical treatment, if necessary, to assure state
Water Quality Standards are not contravened in the receiving stream. Duke Energy shall notify DWR
NPDES Permitting and DWR Mooresville Regional Office, in writing, within seven calendar days of
installing additional physical -chemical treatment at this Outfall.
Page 8 of 25

Permit NC0004979
A. (4.) EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS (Outfall 002A)
[15A NCAC 02B .0400 et seq., 02B .0500 et seq.]
During the period beginning on the effective date of this permit and lasting until expiration, the Permittee is
authorized to discharge from outfall 002A — Coal Yard Sump Overflows. Such discharges shall be limited and
monitored2 by the Permittee as specified below:
EFFLUENT
CHARACTERISTICS
LIMITS
MONITORING REQUIREMENTS
Monthly
Average
Daily
Maximum
Measurement
Frequency
Sample
T� e
Sample Location'
Flow, MGD
Per discharge event
Estimate
Effluent
pH
Between 6.0 and 9.0 standard
units
Per discharge event
Grab
Effluent
Oil and Grease
15.0 mg/L
20.0 mg/L
Per discharge event
Grab
Effluent
Total Suspended Solids
30.0 mg/L
50.0 mg/L
Per discharge event
Grab
Effluent
BOD, 5-day, 20' C4
30.0 mg/L
45.0 mg/L
Per discharge event
Grab
Effluent
Fecal Coliform (geo.
mean 4
200/100 mL
400/100 mL
Per discharge event
Grab
Effluent
Total Copper3
1.0 mg/L
1.0 mg/L
Per discharge event
Grab
Effluent
Total Iron3
1.0 mg/L
1.0 mg/L
Per discharge event
Grab
Effluent
Footnotes:
1. Effluent sampling shall be conducted at a point upstream of discharge to the receiving stream.
2. The pertnittee shall submit Discharge Monitoring Reports electronically using NC DWR's eDMR application
system. Please See Special Condition A. (26.).
3. The limits for total copper and total iron only apply when chemical metal cleaning wastewaters are being
discharged.
4. The limit and monitoring apply only when the domestic wastewater is being discharged to the basin.
There shall be no discharge of floating solids or visible foam in other than trace amounts.
All flows shall be reported on monthly DMRs. If no flow occurs during a given month, the words "no
flow" should be clearly written on the front of the DMR. All samples shall be of a representative discharge.
Page 9 of 25

Permit NC0004979
A. (5.) EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS (Outfall 002B)
[15A NCAC 02B .0400 et seq., 02B .0500 et seq.]
During the period beginning on the effective date of this permit and lasting until expiration, the Permittee is
authorized to discharge from outfall 002B — Power House Sump Overflows. Such discharges shall be limited and
monitored3 by the Permittee as specified below:
EFFLUENT
LIMITS
MONITORING REQUIREMENTS
CHARACTERISTICS
Monthly
Daily
Measurement
Sample Type
Sample
Average
Maximum
Fre uenc�
Location'
Flow, MGD
Per discharge
Estimate
Effluent
event
pH
Between 6.0 and 9.0 standard
Per discharge
Grab
Effluent
units
event
Oil and Grease
15.0 mg/L
20.0 mg/L
Per discharge
Grab
Effluent
event
Total Suspended Solids
30.0 mg/L
100.0 mg/L
Per discharge
Grab
Effluent
event
Total Copper2
1.0 mg/L
1.0 mg/L
Per discharge
Grab
Effluent
event
Total Iron2
1.0 mg/L
1.Omg/L
Per discharge
Grab
Effluent
event
Footnotes:
1. Effluent sampling shall be conducted at a point upstream of discharge to the receiving stream.
2. The limits for total copper and total iron only apply when chemical metal cleaning wastewaters are being
discharged.
3. The permittee shall submit Discharge Monitoring Reports electronically using NC DWR's eDMR application
system. Please See Special Condition A. (26.).
There shall be no discharge of floating solids or visible foam in other than trace amounts.
All flows shall be reported on monthly DMRs. If no flow occurs during a given month, the words "no
flow" should be clearly written on the front of the DMR. All samples shall be of a representative discharge.
Page 10 of 25

Permit NC0004979
A. (6.) EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS (Outfall 003)
[15A NCAC 02B .0400 et seq., 02B .0500 et seq.]
During the period beginning on the effective date of this permit and lasting until expiration, the Permittee is
authorized to discharge from outfall 003 — miscellaneous equipment non -contact water and sealing water.
Such discharges shall be limited and monitored' by the Permittee as specified below:
EFFLUENT
LIMITS
MONITORING REQUIREMENTS
CHARACTERISTICS
Monthly
Daily
Measurement
Sample Type
Sample Location
Average
Maximum
Frequency
Flow, MGD
Weekly
Estimate
Effluent
Footnotes:
1. The permittee shall submit Discharge Monitoring Reports electronically using NC DWR's eDMR application
system. Please See Special Condition A. (26.).
Chlorination of the once through cooling water, discharged through outfall 003, is not allowed under this
permit. If Duke Energy Carolinas, LLC wishes to chlorinate this once through cooling water, a permit
modification must be obtained beforehand.
A. (7.) EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS (Outfall 004)
[15A NCAC 02B .0400 et seq., 02B .0500 et seq.]
During the period beginning on the effective date of this permit and lasting until expiration, the Permittee is
authorized to discharge from outfall 004- miscellaneous non -contact cooling water, vehicle washwater, and
intake screen backwash. Such discharges shall be limited and monitored' by the Permittee as specified below:
EFFLUENT
CHARACTERISTICS
LIMITS
MONITORING REQUIREMENTS
Monthly
Average I
Daily
Maximum
Measurement
Fr uen
Sample Type
Sample
Location
Flow, MGD
Weekly
Estimate
Effluent
Oil and Grease
15.0 mg/L
20.0 mg/L
Quarterly
Grab
Effluent
Footnotes:
1. The permittee shall submit Discharge Monitoring Reports electronically using NC DWR's eDMR application
system. Please See Special Condition A. (26.).
Chlorination of the once through cooling water, discharged through outfall 004, is not allowed under this
permit. If Duke Energy Carolinas, LLC wishes to chlorinate this once through cooling water, a permit
modification must be obtained beforehand.
Page 11 of 25

Permit NC0004979
A. (8.) EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS (Internal Outfall 005)
[15A NCAC 02B .0400 et seq., 02B .0500 et seq.]
During the period beginning on the effective date of this permit and lasting until permit expiration, the Permitee is
authorized to discharge from internal outfall 005- treated FGD wet scrubber wastewater to ash settling basin.
Such discharges shall be limited and monitored2 by the Permittee asspecified below:
EFFLUENT
CHARACTERISTICS
LIMITS
MONITORING REQUIREMENTS
Monthly Daily
Average I Maximum
Measurement
Frequency
Sample
Type
Sample
Location'
Flow, MGD
Monitor & Report
Monthly
Pump logs or
similar
readirV,s
Effluent
Total Arsenic
8.0 µg/L4
11.0 µg/L4
Quarterly
Grab
Effluent
Total Mercury3, ng/L
356.0 ng/L4
788.0 ng/L4
Quarterly
Grab
Effluent
Total Selenium
12.0 µg/L4
23.0 µg/L4
Quarterly
Grab
Effluent
Nitrate/nitrite as N
4.4 mg/L4
1 17.0 mg/L4
Quarterly
Grab
Effluent
PH
Monthly
Grab
Effluent
Footnotes:
1. "Effluent" shall be defined as the discharge from the FGD wastewater treatment system prior to commingling
with other waste streams.
2. The permittee shall submit Discharge Monitoring Reports electronically using NC DWWs eDMR
application system. Please See Special Condition A. (26.).
3. The facility shall use method 1631E.
4. In accord with the Steam Electric Effluent Limitations Guidelines for FGD wastewater (40 C.F.R.
423), these limits shall become effective on February 28, 2020. This permit may be reopened and
modified if changes are made to 40 C.F.R. 423.
This permit shall be reopened and modified to reflect any changes in the 40 CFR 423.
All flows shall be reported on monthly DMRs. If no flow occurs during a given month, the words "no
flow" shall be clearly written on the front of the DMR. All samples shall be of a representative discharge.
The facility shall operate the FGD treatment system until all coal-fired units are retired.
Page 12 of 25

Permit NC0004979
A. (9.) EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS (Outfall 006)
[15A NCAC 02B .0400 et seq., 02B .0500 et seq.]
During the period beginning upon commencement of operations and lasting until expiration, the Permittee is
authorized to discharge from outfall 006 — Retention Basin discharge. Such discharges shall be limited and
monitored' b- the Permittee as specified below:
EFFLUENT
CHARACTERISTICS
DISCHARGE LIMITATIONS
MONITORING REQUIREMENTS
Monthly
Average
Daily
Maximum
Measurement
Frequency
Sample
Type
Sample
Location
Flow, MGD
Weekly
Instantaneous
or Estimate
Effluent
pH
Between 6.0 and 9.0 standard
units
Monthly
Grab
Effluent
TSS
30.0 m /L
100.0 /L
Monthhv
Grab
Effluent
Oil and Grease
15.0 /L
20.0 /L
Monthly
Grab
Effluent
BOD, 5-da •, 20' C5
30.0 /L
45.0 mg1L
Monthly
Grab
Effluent
Fecal Coliform eo. mean 5
200/100 mL
400/100 mL
Monthly
Grab
Effluent
Fluoride, /L
Mon—d±Grab
Effluent
Total Mercury z, n /L
Monthly
Grab
Effluent
Total Silver
1.17 Etg/L
4.79 /L
Monthly
Grab
Effluent
Total Iron3
1.0 m /L
1.0 m /L
Monthly
Grab
Effluent
Total Zinc, /L
Monthl •
Grab
Effluent
Total Arsenic, /L
Monthly
Grab
Effluent
Total Cadmium, /L
Monthh
Grab
Effluent
Total Chromium, /L
Monthl%
Grab
Effluent
Total Co era
1.0 mq/L
1.0 /L
Monthly
Grab
Effluent
Total Lead, /L
Monthly
Grab
Effluent
Total Nickel, /L
Monthly
Grab
Effluent
Total Selenium, /L
Monthly
Grab
Effluent
Total Nitrogen
02+NO3+TKN,m /L
Quarterly
Grab
Effluent
Total Phosphorus, m /L
Quarterly
Grab
Effluent
Sulfates, m /L
Monthly
Grab
Effluent
Chlorides, /L
Monthly
Grab
Effluent
Bromide, m /L
Monthly
Grab
Effluent
TDS, /L
Monthly
Grab
Effluent
Total Hardness, /L
Monthh,
Grab
Effluent
Temperature, OC
Monthly
Grab
Effluent
Conductivity, µmho/cm
Monthly
Grab
Effluent
Chronic Toxicity4
Monthy,
Grab
Effluent
Footnotes:
1. The permittee shall submit Discharge Monitoring Reports electronically using NC DWR's eDMR application
system. Please See Special Condition A. (26.).
2. The facility shall use EPA method 1631E.
3. The limits for total copper and total iron only apply when chemical metal cleaning wastewaters are being
discharged.
4. Whole Effluent Toxicity shall be monitored by chronic toxicity (Ceriodaphnia) P/F at 5.1%, see Special
Condition A. (17.).
5. The limit and monitoring apply only when the domestic wastewater is being discharged to the basin.
There shall be no discharge of floating solids or visible foam in other than trace amounts.
Page 13 of 25

Permit NC0004979
The facility shall submit EPA Form 2C for Outfall 006 no later than 180 days from the commencement of
the discharge. The facility shall notify DWR/NPDES, in writing, 30 days prior to the commencement of
the discharge from this outfall.
A. (10.) EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS (Outfall 007)
[15A NCAC 02B .0400 et seq., 02B .0500 et seq.]
During the period beginning on the effective date of this permit and lasting until expiration, the Permittee is
authorized to discharge from outfall 007 — Emergency spillway of the new Retention Basin. Such discharges shall be
limited and monitored' by the Permittee as specified below:
EFFLUENT
CHARACTERISTICS
DISCHARGE LIMITATIONS
MONITORING REQUIREMENTS
Monthly
Average
f Daily
Maximum
Measurement
Fre uencv
Sample
T e
Sample
Location
Flow, MGD
��
Waived
Estimate
Effluent
pH
Waived
Grab
Effluent
TSS
Waived
Grab
Effluent
Oil and Grease
Waived
Grab
Effluent
The emergency spillway is designed for a flood greater than 100-year event in Gaston County. Sampling of
this spillway is waived due to unsafe conditions associated with sampling during an overflow event.
Monitoring is required for any other rain event that might trigger a discharge.
A. (11.) EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS (Outfall 008)
[15A NCAC 02B .0400 et seq., 02B .0500 et seq.]
During the period beginning on the effective date of this permit and lasting until expiration, the Permittee is
authorized to discharge from outfall 008 — Emergency spillway of the retired ash basin. Such discharges shall be
limited and monitored' b,. the Permittee as specified below:
EFFLUENT
CHARACTERISTICS
DISCHARGE LIMITATIONS
MONITORING REQUIREMENTS
Monthly
Avera a
Daily
I Maximum
Measurement
Fre uency
Sample
Tay a
Sample
Location
Flow, MGD
Waived
Estimate
Effluent
pH
Waived
Grab
Effluent
TSS
Waived
Grab
Effluent
Oil and Grease
Waived
Grab
Effluent
The emergency spillway is designed for a flood greater than 100-year event in Gaston County. Sampling of
this spillway is waived due to unsafe conditions associated with sampling during an overflow event.
Monitoring is required for any other rain event that might trigger a discharge.
Page 14 of 25

Permit NC0004979
A. (12.) EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS (Outfall 103)
[15A NCAC 02B .0400 et seq., 02B .0500 et seq]
During the period beginning on the effective date of this permit and lasting until expiration, the Permittee is
authorized to discharge from outfall 103 — Toe Drain Discharge. Such discharges shall be limited and monitored' by
the Permittee as specified below:
EFFLUENT
CHARACTERISTICS
DISCHARGE LIMITATIONS
MONITORING REQUIREMENTS
Monthly
Avery a
Daily
Maximum
Measurement
Fre uency2
Sample
Tv a
Sample
Location
Flow, MGD
Monthly/Quarterl-
Estimate
Effluent
2-H3
Month' /Quarterly
Grab
Effluent
TSS
30.0 /L
100.0 /L
Month' / uarterl ,
Grab
Effluent
Oil and Grease
15.0 /L
20.0 m /L
Monthly/Quarterly
Grab
Effluent
Fluoride, m /L
Monthly/Quarterly
Grab
Effluent
Total Merc►a 4, /L
Monthly/quarterly
Grab
Effluent
Total Barium, m /L
Monthly/Quarterl-
Grab
Effluent
Total Iron, /L
Monthly /Quarterl •
Grab
Effluent
Total Manganese, µ T/L
Monthly/Quarterly
Grab
Effluent
Total Zinc, t,
A/L
Monthly/QuarteAl
Grab
Effluent
Total Arsenic, µ /L
Monthly/Quarterly
Grab
Effluent
Total Cadmium, /L
Monthly/Quarterl •
Grab
Effluent
Total Chromium, /L
Monthly/Quarterly
Grab
Effluent
Total Copper, /L
Monthly/Quarterl •
Grab
Effluent
Total Lead, /L
Monthly/Quarterly
Grab
Effluent
Total Nickel, /L
Monthly/ uarterl
Grab
Effluent
Total Selenium, /L
Month'-/ uarterl-
Grab
Effluent
Nitrate as N, /L
Monthly /Quarterl
Grab
Effluent
Sulfates, /L
Monthly /Quarterly
Grab
Effluent
Chlorides, m /L
Monthly/Quarterly
Grab
Effluent
TDS, m /L
Monthly/Quarterly
Grab
Effluent
Total Hardness, m . /L
Monthly/QuarterlyMonthly/Quarterly
Grab
Effluent
Tem erature, °C
Monthly /Quarterly
Grab
Effluent
Conductivity, µmho/cm
Month1v /Quarterly I
Grab
Effluent
Footnotes:
1. The pertnittee shall submit Discharge Monitoring Reports electronically using NC DWR's eDMR application
system. Please See Special Condition A. (26.).
2. The facility shall conduct monthly sampling from the effective date of the permit. After one year from the
effective date of the permit the monitoring will be reduced to quarterly
3. The pH shall not be less than 6.0 standard units nor greater than 9.0 standard units.
4. The facility shall use EPA method 1631E.
If no discharge occurs during the reporting period or the Permittee is unable to obtain a representative
sample due to low -flow conditions at the toe drain, the Permittee shall submit its DMR, as required, and
indicate "No Flow" for the toe drain (15A NCAC 02B .0506(a) (1) (E)).
There shall be no discharge of floating solids or visible foam in other than trace amounts.
Page 15 of 25

Permit NC0004979
A. (13.) EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS (Outfall 104)
[15A NCAC 02B .0400 et seq., 02B .0500 et seq.]
During the period beginning on the effective date of this permit and lasting until expiration, the Permittee is
authorized to discharge from outfall 104 — Toe Drain Discharge. Such discharges shall be limited and monitored' by
the Permittee as specified below
EFFLUENT
CHARACTERISTICS
DISCHARGE LIMITATIONS
MONITORING REQUIREMENTS
Monthly
AverMe
Daily
Maximum
Measurement
Fre uencv2
Sample
Type
Sample
Location
Flow, MGD
Monthly/Quarterly
Estimate
Effluent
H3
Monthly/Quarterly
Grab
Effluent
TSS
30.0 tn/L
100.0 m r/L
Month' / uarterl -
Grab
Effluent
Oil and Grease
15.0 m /L
20.0 m /L
Monthly/Quarterly
Grab
Effluent
Fluoride, /L
Monthh,/Quarterl •
Grab
Effluent
Total Mercu , n /L
Month' ,/Quarterl •
Grab
Effluent
Total Barium, m /L
Monthly / uarterly
Grab
Effluent
Total Iron, /L
Monthly/Quarterly
Grab
Effluent
Total Manganese, /L
Monthly/Quarterly
Grab
Effluent
Total Zinc, /L
Monthly/Quarterl •
Grab
Effluent
Total Arsenic, /L
Monthl -/ uarterly
Grab
Effluent
Total Cadmium, µ /L
Monthly/Quarterly
Grab
Effluent
Total Chromium, /L
Monthly /Quarterl•
Grab
Effluent
Total Copper, /L
Monthly/ uarterly
Grab
Effluent
Total.Lead, /L
Monthly/Quarterly
Grab
Effluent
Total Nickel, /L
Monthly/Quarterly
Grab
Effluent
Total Selenium, /L
Monthly/Quarterl •
Grab
Effluent
Nitrate as N, /L
Monthly /Quarterl -
Grab
Effluent
Sulfates, /L
Monthly -/Quarterly
Grab
Effluent
Chlorides, m /L
Monthl •/Quarterl -
Grab
Effluent
'IDS, /L
Monthly/Quarterly
Grab
Effluent
Total Hardness, /L
Monthly /Quarterly
Grab
Effluent
Temperature, OC
Month/Quarterly
Grab
Effluent
Conductivin, µmho/cm
Monthly/Quarterly
Grab
Effluent
Footnotes:
1. The permittee shall submit Discharge Monitoring Reports electronically using NC DWR's eDMR application
system. Please See Special Condition A. (26.).
2. The facility shall conduct monthly sampling from the effective date of the permit. After one year from the
effective date of the permit the monitoring will be reduced to quarterly
3. The pH shall not be less than 6.0 standard units nor greater than 9.0 standard units.
4. The facility shall use EPA method 1631E.
If no discharge occurs during the reporting period or the Permittee is unable to obtain a representative
sample due to low -flow conditions at the toe drain, the Permittee shall submit its DMR, as required, and
indicate "No Flow" for the toe drain (15A NCAC 02B .0506(a)(1)(E)).
There shall be no discharge of floating solids or visible foam in other than trace amounts.
Page 16 of 25

Permit NC0004979
A. (14.) EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS (Outfall 108)
[15A NCAC 02B .0400 et seq., 02B .0500 et seq.]
During the period beginning on the effective date of this permit and lasting until expiration, the Permittee is
authorized to discharge from outfall 108 — Toe Drain Discharge. Such discharges shall be limited and monitored' by
the Permittee as specified below:
EFFLUENT
CHARACTERISTICS
DISCHARGE LIMITATIONS
MONITORING REQUIREMENTS
Monthly
Average
Daily
Maximum
Measurement
I Fre uencN-2
Sample
Type
Sample
Location
Flow, MGD
Monthl •/Quarterl)-
Estimate
Effluent
H3
Monthl •/Quarterly-
Grab
Effluent
TSS
30.0 /L
100.0 /L
Monthly/Quarterly
Grab
Effluent
Oil and Grease
15.0 m /L
20.0 /L
Monthly/QuarterlyMonthly/Quarterly
Grab
Effluent
Fluoride, m /L
Monthl •/Quarterl •
Grab
Effluent
Total Mercury-', /L
Monthly/Quarterly
Grab
Effluent
Total Barium, /L
Monthly /Quarterly
Grab
Effluent
Total Iron, /L
Monthly/Quarterly
Grab
Effluent
Total Manganese, /L
Monthly/Quarterly
Grab
Effluent
Total Zinc, >/L
Monthly/Quarterly
Grab
Effluent
Total Arsenic, /L
Monthly/Quarterly
Grab
Effluent
Total Cadmium, /L
Monthly./ ]uarterl •
Grab
Effluent
Total Chromium, /L
Monthh•/Quarterly
Grab
Effluent
Total Copper, /L
Monthly/Quarterly
Grab
Effluent
Total Lead, µ /L
Monthly/Quarterly
Grab
Effluent
Total Nickel, /L
Monthly/Quarterly
Grab
Effluent
Total Selenium, /L
Monthly/QuarterlyMonthly/Quarterly
Grab
Effluent
Nitrate as N, m /L
Monthly/Quarterly
Grab
Effluent
Sulfates, /L
Monthly/ Quarterly
Grab
Effluent
Chlorides, /L
Monthly/Quarterly
Grab
Effluent
-IDS, /L
Monthly/Quarterly
Grab
Effluent
Total Hardness, /L
Monthly /Quarterly
Grab
Effluent
Tem erature, °C
Monthly/ uarterly
Grab
Effluent
Conductivity, µmho/cm
Monthly /Quarterl y
Grab
Effluent
Footnotes:
1. The permittee shall submit Discharge Monitoring Reports electronically using NC DWR's eDMR application
system. Please See Special Condition A. (26.).
2. The facility shall conduct monthly sampling from the effective date of the permit. After one year from the
effective date of the permit the monitoring will be reduced to quarterly
3. The pH shall not be less than 6.0 standard units nor greater than 9.0 standard units.
4. The facility shall use EPA method 1631E.
If no discharge occurs during the reporting period or the Permittee is unable to obtain a representative
sample due to low -flow conditions at the toe drain, the Permittee shall submit its DMR, as required, and
indicate "No Flow" for the toe drain (15A NCAC 02B .0506(a)(1)(E)).
There shall be no discharge of floating solids or visible foam in other than trace amounts.
Page 17 of 25

Permit NC0004979
A. (15.) EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS (Outfall 108B)
[15A NCAC 02B .0400 et seq., 02B .0500 et seq.]
During the period beginning on the effective date of this permit and lasting until expiration, the Permittee is
authorized to discharge from outfall 108B — Toe Drain Discharge. Such discharges shall be limited and monitored'
b,: the Permittee as specified below:
EFFLUENT
CHARACTERISTICS
DISCHARGE LIMITATIONS
MONITORING REQUIREMENTS
Monthly
Average
Daily
Maximum
Measurement
Fre uencv2
Sample
Type aLocation
Sample
Flow, MGD
Monthly/Quarterl
Estimate
Effluent
H3
Monthly/Quarterly
Grab
Effluent
TSS
30.0 g/L
100.0 /L
Monthl •/Quarterl r
Grab
Effluent
Oil and Grease
15.0 /L
20.0 /L
Monthly/ uarterlF
Grab
Effluent
Fluoride, m /L
Monthly/Quarterly
Grab
Effluent
Total Mercury4, n /L
Monthly/Quarterl-
Grab
Effluent
Total Barium, /L
Monthly/Quarterly
Grab
Effluent
Total Iron, /L
Monthly/Quarterly
Grab
Effluent
Total Manganese, /L
Monthly/Quarterly
Grab
Effluent
Total Zinc, /L
Monthly/Quarterly
Grab
Effluent
Total Arsenic, /L
Monthly/Quarterly
Grab
Effluent
Total Cadmium, /L
Monthlyy/Quarterl -
Grab
Effluent
Total Chromium, /L
Monthly/Quarterly
Grab
Effluent
Total Copper, /L
Monthly/Quarterl-
Grab
Effluent
Total Lead, /L
Monthly /Quarterl)-
Grab
Effluent
Total Nickel, /L
Monthly/Quarterl-
Grab
Effluent
Total Selenium, /L
Monthly/Quarterly
Grab
Effluent
Nitrate as N, m /L
Monthly/Quarterly
Grab
Effluent
Sulfates, /L
Monthly-/ uarterly
Grab
Effluent
Chlorides, /L
Mon / uarterl y
Grab
Effluent
TDS, m /L
Monthly/Quarterly
Grab
Effluent
Total Hardness, mp,/L
Mond-Ay/Quarterly
Grab
Effluent
Temperature, OC
Monthh./Quarterly
Grab
Effluent
Conductivity-, µmho/cm
i
Monthly/Quarterly
Grab
Effluent
Footnotes:
1. The permittee shall submit Discharge Monitoring Reports electronically using NC DWR's eDMR application
system. Please See Special Condition A. (26.).
2. The facility shall conduct monthly sampling from the effective date of the permit. After one year from the
effective date of the permit the monitoring will be reduced to quarterly
3. The pH shall not be less than 6.0 standard units nor greater than 9.0 standard units.
4. The facility shall use EPA method 1631E.
If no discharge occurs during the reporting period or the Permittee is unable to obtain a representative
sample due to low -flow conditions at the toe drain, the Permittee shall submit its DMR, as required, and
indicate "No Flow" for the toe drain (15A NCAC 02B .0506(a)(1)(E)).
There shall be no discharge of floating solids or visible foam in other than trace amounts.
Page 18 of 25

Permit NC0004979
A. (16.) SPECIAL CONDITION FOR THE DISCHARGE OF ASIATIC CLAM/DEBRIS FILTER
BACKWASH
[NCGS 143-215.3 (a) (2) and NCGS 143-215.66]
The permittee may backwash the intake filter for Unit 5 condenser cooling water on an as -needed basis. It is
understood that this wash water will contain materials indigenous to the Catawba River such as Asiatic clams and
light debris. As these are naturally occurring in the river environment, they may be discharged with no adverse
affects to the receiving stream. The Permittee may not add any detergent, chemicals or other non -indigenous
material to the wash water without explicit permission from the Division of Water Resources.
A. (17.) CHRONIC TOXICITY PASS/FAIL PERMIT LIMIT (QUARTERLY/MONTHLY) (Outfall 002
and Outfall 006)
[15A NCAC 02B .0200 et seq.]
The effluent discharge shall at no time exhibit observable inhibition of reproduction or significant mortality to
Ceriodaphnia dubia at an effluent concentration of 23.6% for decanting/normal operations (Outfall 002), 5.1%
for retention basin discharge (Outfall 006), and 1.6% for dewatering (Outfall 002).
The permit holder shall perform at a minimum, qua rer (for normal operation/decanting at Outfall 002 and Outfall
006), and monthly (for dewatering at Outfall 002) monitoring using test procedures outlined in the "North Carolina
Ceriodaphnia Chronic Effluent Bioassay Procedure," Revised December 2010, or subsequent versions or "North
Carolina Phase II Chronic Whole Effluent Toxicity Test Procedure" (Revised- December 2010) or subsequent
versions. Effluent sampling for this testing must be obtained during representative effluent discharge and shall be
performed at the NPDES permitted final effluent discharge below all treatment processes.
If the test procedure performed as the first test of any single month results in a failure or ChV below the
permit limit, then multiple -concentration testing shall be performed at a minimum, in each of the two
following months as described in "North Carolina Phase II Chronic Whole Effluent Toxicity Test
Procedure" (Revised -December 2010) or subsequent versions.
All toxicity testing results required as part of this permit condition will be entered on the Effluent Discharge
Monitoring Form (MR-1) for the months in which tests were performed, using the parameter code TGP3B for the
pass/fail results and THP3B for the Chronic Value. Additionally, DWR Form AT-3 (original) is to be sent to the
following address: Attention: North Carolina Division of Water Resources
Water Sciences Section/Aquatic Toxicology Branch
1621 Mail Service Center
Raleigh, North Carolina 27699-1621
Completed Aquatic Toxicity Test Forms shall be filed with the Water Sciences Section no later than 30 days after
the end of the reporting period for which the report is made.
Test data shall be complete, accurate, include all supporting chemical/physical measurements and all
concentration/response data, and be certified by laboratory supervisor and ORC or approved designate signature.
Total residual chlorine of the effluent toxicity sample must be measured and reported if chlorine is employed for
disinfection of the waste stream.
Should there be no discharge of flow from the facility during a month in which toxicity monitoring is required, the
permittee will complete the information located at the top of the aquatic toxicity (AT) test form indicating the
facility name, permit number, pipe number, county, and the month/year of the report with the notation of "No
Flow" in the comment area of the form. The report shall be submitted to the Water Sciences Section at the address
cited above.
Should the permittee fail to monitor during a month in which toxicity monitoring is required, monitoring will be
required during the following month. Assessment of toxicity compliance is based on the toxicity testing quarter,
Page 19 of 25

Permit NC0004979
which is the three month time interval that begins on the first day of the month in which toxicity testing is required
by this permit and continues until the final day of the third month.
Should any test data from this monitoring requirement or tests performed by the North Carolina Division of Water
Resources indicate potential impacts to the receiving stream, this permit may be re -opened and modified to include
alternate monitoring requirements or limits.
NOTE: Failure to achieve test conditions as specified in the cited document, such as minimum control organism
survival, minimum control organism reproduction, and appropriate environmental controls, shall constitute an
invalid test and will require immediate follow-up testing to be completed no later than the last day of the month
following the month of the initial monitoring.
A. (18.) BIOCIDE CONDITION
[NCGS 143-215.1]
The permittee shall not use any biocides except those approved in conjunction with the permit application. The
permittee shall notify the Director in writing not later than ninety (90) days prior to instituting use of any additional
biocide used in cooling systems which may be toxic to aquatic life other than those previously reported to the Division
of Water Resources. Such notification shall include completion of Biocide Worksheet Form 101 and a map locating
the discharge point and receiving stream. Completion of Biocide Worksheet Form 101 is not necessary for those
outfalls containing toxicity testing. Division approval is not necessary for the introduction of new biocides into outfalls
currently tested for whole effluent toxicity.
A. (19.) ADDITIONAL CONDITIONS AND DEFINITIONS
[NCGS 143-215.3 (a) (2) and NCGS 143-215.661
1. EPA methods 200.7 or 200.8 (or the most current versions) shall be used for analyses of all metals except
for total mercury (EPA Method 1631E).
2. All effluent samples for all external outfalls shall be taken at the most accessible location after the final
treatment but prior to discharge to waters of the U.S. (40 CFR 122.41(j)).
3. The term low volume waste sources means wastewater from all sources except those for which specific
limitations are otherwise established in this part (40 CFR 423.11 (b)).
4. The term chemical metal cleaning waste means any wastewater resulting from cleaning any metal process
equipment with chemical compounds, including, but not limited to, boiler tube cleaning (40 CFR 423.11
(c))•
5. The term metal cleaning waste means any wastewater resulting from cleaning [with or without chemical
cleaning compounds] any metal process equipment including, but not limited to, boiler tube cleaning, boiler
fireside cleaning, and air preheater cleaning (40 CFR 423.11 (d)).
6. For all outfalls where the flow measurement is to be "estimated" the estimate can be done by using
calibrated V-notch weir, stop -watch and graduated cylinder, or other method approved by the Division.
7. The term "FGD wet scrubber wastewater" means wastewater resulting from the use of the flue -gas
desulfurization wet scrubber.
8. There shall be no discharge of polychlorinated biphenyl compounds.
9. The permittee shall report the presence of cenospheres observed in any samples on the DMRs.
10. The applicant is permitted to discharge chemical metal cleaning wastes to the ash basin.
11. Nothing contained in this permit shall be construed as a waiver by the permittee of any right to a hearing it
may have pursuant to State or Federal laws and regulations.
A. (20.) STRUCTURAL INTEGRITY INSPECTIONS OF ASH DAMS
[15A NCAC 02K.0208]
The facility shall meet the dam design and dam safety requirements per 15A NCAC 2K
Page 20 of 25

Permit NC0004979
A. (21.) CLEAN WATER ACT SECTION 316 (a) THERMAL VARIANCE
[40 CFR 125, Subpart H]
The thermal variance granted under Section 316(a) terminates on expiration of this NPDES permit. Should the
permittee wish a continuation of its 316(a) thermal variance beyond the term of this permit, reapplication for such
continuation shall be submitted in accordance with 40 CFR Part 125, Subpart H and Section 122.21(m)(6) not later
than 3.5 years from the effective date of the permit. Reapplication shall include a basis for continuation such as a)
plant operating conditions and load factors are unchanged and are expected to remain so for the term of the
reissued permit; b) there are no changes to plant discharges or other discharges in the plant site area which could
interact with the thermal discharges; and c) there are no changes to the biotic community of the receiving water
body which would impact the previous variance determination.
The next 316(a) studies shall be performed in accordance with the Division of Water Resources approved plan. The
temperature analysis and the balanced and indigenous study plan shall conform to the specifications outlined in 40
CFR 125 Subpart H, the EPA's Draft 316(a) Guidance Manual, dated 1977, and the Region 4 letter to NCDENR,
dated June 3, 2010. EPA shall be provided an opportunity to review the plan prior to the commencement of the
study.
The facility shall select a new cold water reference area approved by the Division of Water Resources
during the next 316(a) study.
Copies of all the study plans, study results, and any other applicable materials should be submitted to:
1) Electronic Version Only (pdf and CD)
Division of Water Resources
WQ Permitting Section - NPDES
1617 Mail Service Center
Raleigh, NC 27699-1617
2) Electronic Version (pdf and CD) and Hard Copy
Division of Water Resources
Water Sciences Section
1623 Mail Service Center
Raleigh, NC 27699-1623
A. (22.) CLEAN WATER ACT SECTION 316 (b)
[40 CFR 125.95]
The permittee shall comply with the Cooling Water Intake Structure Rule per 40 CFR 125.95. The permittee shall
submit all the materials required by the Rule 3.5 years from the effective date of the permit.
Copies of all the study plans, study results, and any other applicable materials should be submitted to:
1) Electronic Version Only (pdf and CD)
Division of Water Resources
WQ Permitting Section - NPDES
1617 Mail Service Center
Raleigh, NC 27699-1617
2) Electronic Version (pdf and CD) and Hard Copy
Division of Water Resources
Water Sciences Section
1623 Mail Service Center
Raleigh, NC 27699-1623
Page 21 of 25

Permit NCO004979
Pursuit to 40 CFR 125.98 the Director has determined that operating and maintaining the existing traveling screen
system which includes a fish handling return system meets the requirements for the interim BTA.
Nothing in this permit authorizes take for the purposes of a facility's compliance with the Endangered Species Act.
A. (23.) FISH TISSUE MONITORING NEAR ASH POND DISCHARGE
[NCGS 143-215.3 (a) (2)]
The facility shall conduct fish tissue monitoring annually and submit the results with the NPDES permit renewal
application. The objective of this monitoring is to evaluate potential uptake of pollutants by fish tissue near the ash
pond discharge. The parameters analyzed in fish tissue shall be arsenic, selenium, and mercury. The monitoring shall
be conducted in accordance with the sampling plan approved by the Division. The plan should be submitted to the
Division within 180 days from the effective date of the permit. Upon approval, the plan becomes an enforceable part
of the permit.
Copies of all the study plans, study results, and any other applicable materials should be submitted to:
1) Electronic Version Only (pdf and CD)
Division of Water Resources
WQ Permitting Section - NPDES
1617 Mail Service Center
Raleigh, NC 27699-1617
2) Electronic Version (pdf and CD) and Hard Copy
Division of Water Resources
Water Sciences Section
1623 Mail Service Center
Raleigh, NC 27699-1623
A. (24.) INSTREAM MONITORING
[15A NCAC 02B.0500 ET SEQ.]
The facility shall conduct monthly in -stream monitoring for total arsenic, total selenium, total mercury, total
chromium, dissolved lead, dissolved cadmium, dissolved copper, dissolved zinc, total bromide, total hardness (as
CaCO3), turbidity, temperature, and total dissolved solids (IDS). The monitoring results shall be reported on the
facility's Discharge Monitoring Reports and included with the NPDES permit renewal application. The upstream site
(Station 250) is approximately 1.1 miles upstream of the discharge and the downstream location is approximately 250
meters downstream of the discharge.
A. (25.) PRIORITY POLLUTANT ANALYSIS
[NCGS 143-215.1 (b)]
The permittee shall conduct a priority pollutant analysis (in accordance with 40 CFR Part 136) once per permit cycle
at all external outfalls and submit the results with the application for permit renewal.
A. (26.) ELECTRONIC REPORTING OF DISCHARGE MONITORING REPORTS
[G.S. 143-215.1(b)]
Federal regulations require electronic submittal of all discharge monitoring reports (DMRs) and program reports.
The final NPDES Electronic Reporting Rule was adopted and became effective on December 21, 2015.
NOTE: This special condition supplements or supersedes the following sections within Part II of this permit
(Standard Conditions for NPDES Permits):
• - Section B. (11.) Signatory Requirements
Page 22 of 25

Permit NC0004979
• Section D. (2.)
• Section D. (6.)
• Section E. (5.)
Reporting
Records Retention
Monitoring Reports
1. Reporting Requirements (Supersedes Section D. (2.) and Section E. (5.)
The permittee shall report discharge monitoring data electronically using the NC DWR's Electronic Discharge
Monitoring Report (eDMR) internet application.
Monitoring results obtained during the previous month(s) shall be summarized for each month and submitted
electronically using eDMR. The eDMR system allows permitted facilities to enter monitoring data and submit
DMRs electronically using the internet. Until such time that the state's eDMR application is compliant with
EPA's Cross -Media Electronic Reporting Regulation (CROMERR), permittees will be required to submit all
discharge monitoring data to the state electronically using eDMR and will be required to complete the eDMR
submission by printing, signing, and submitting one signed original and a copy of the computer printed eDMR
to the following address:
NC DEQ / Division of Water Resources / Water Quality Permitting Section
ATTENTION: Central Files
1617 Mail Service Center
Raleigh, North Carolina 27699-1617
If a permittee is unable to use the eDMR system due to a demonstrated hardship or due to the facility being
physically located in an area where less than 10 percent of the households have broadband access, then a
temporary waiver from the NPDES electronic reporting requirements may be granted and discharge monitoring
data may be submitted on paper DMR forms (MR 1, 1.1, 2, 3) or alternative forms approved by the Director.
Duplicate signed copies shall be submitted to the mailing address above. See "How to Request a Waiver from
Electronic Reporting" section below.
Regardless of the submission method, the first DMR is due on the last day of the month following the issuance
of the permit or in the case of a new facility, on the last day of the month following the commencement of
discharge.
Starting on December 21, 2020, the permittee must electronically report the following compliance monitoring
data and reports, when applicable:
Sewer Overflow/Bypass Event Reports;
Pretreatment Program Annual Reports; and
Clean Water Act (CWA) Section 316(b) Annual Reports.
The permittee may seek an electronic reporting waiver from the Division (see "How to Request a Waiver from
Electronic Reporting" section below).
2. Electronic Submissions
In accordance with 40 CFR 122.41 (1) (9), the permittee must identify the initial recipient at the time of each
electronic submission. The permittee should use the EPA's website resources to identify the initial recipient for
the electronic submission.
Initial recipient of electronic NPDES information from NPDES-regulated facilities means the entity (EPA or
the state authorized by EPA to implement the NPDES program) that is the designated entity for receiving
electronic NPDES data [see 40 CFR 127.2(b)].
Page 23 of 25

Permit NC0004979
EPA plans to establish a website that will also link to the appropriate electronic reporting tool for each type of
electronic submission and for each state. Instructions on how to access and use the appropriate electronic
reporting tool will be available as well. Information on EPA's NPDES Electronic Reporting Rule is found at:
htg2s:I/www.federalre�rister ovldocuments/2015110122/2015-24954/national-pollutant-discharge-
e_l"adon-s►• stem-npdes-electronic-reporting-rule
Electronic submissions must start by the dates listed in the "Reporting Requirements" section above.
3. How to Request a Waiver from Electronic Reporting
The permittee may seek a temporary electronic reporting waiver from the Division. To obtain an electronic
reporting waiver, a permittee must first submit an electronic reporting waiver request to the Division. Requests
for temporary electronic reporting waivers must be submitted in writing to the Division for written approval at
least sixty (60) days prior to the date the facility would be required under this permit to begin submitting
monitoring data and reports. The duration of a temporary waiver shall not exceed 5 years and shall thereupon
expire. At such time, monitoring data and reports shall be submitted electronically to the Division unless the
permittee re -applies for and is granted a new temporary electronic reporting waiver by the Division. Approved
electronic reporting waivers are not transferrable. Only permittees with an approved reporting waiver request
may submit monitoring data and reports on paper to the Division for the period that the approved reporting
waiver request is effective.
Information on eDMR and the application for a temporary electronic reporting waiver are found on the
following web page:
http: / /deq.nc.govY about/divisions/water-resources/ edmr
4. Si^natory Requirements [Supplements Section B. (11.) (b1 and Supersedes Section B. (11.)(d11
All eDMRs submitted to the permit issuing authority shall be signed by a person described in Part II, Section B.
(11.)(a) or by a duly authorized representative of that person as described in Part II, Section B. (11.)(b). A
person, and not a position, must be delegated signatory authority for eDMR reporting purposes.
For eDMR submissions, the person signing and submitting the DMR must obtain an eDMR user account and
login credentials to access the eDMR system. For more information on North Carolina's eDMR system,
registering for eDMR and obtaining an eDMR user account, please visit the following web page:
ht tp:1 / deq.nc.gov/about/divisions/water-resources/edmr
Certification. Any person submitting an electronic DMR using the state's eDMR system shall make the
following certification [40 CFR 122.221. NO OTHER STATEMENTS OF CERTIFICATION WILL BE
ACCEPTED:
"I ceriz�, underpenaldy of law, that this document and all attachments were prepared under my direction or supervision in
accordance with a system designed to assure that qualified personnel pra. p y ather and evaluate the information submitted Based
on my inquiry of the person or persons who manage the system, or those persons directly responsible forgathering the information, the
information submitted is, to the best of my knowledge and belief, tare, accurate, and complete. I am aware that there are significant
penalties for submitting false information, including the possibility of fines and imprisonment for knowing violations. "
5. Records Retention (Supplements Section D. (6.1
The permittee shall retain records of all Discharge Monitoring Reports, including eDMR submissions. These
records or copies shall be maintained for a period of at least 3 years from the date of the report. This period
may be extended by request of the Director at any time [40 CFR 122.41].
Page 24 of 25

Permit NC0004979
A. (27.) APPLICABLE STATE LAW (State Enforceable Only)
[NCGS 143-215.1(b)]
This facility shall meet the General Statute requirements under NCGS 5 130A-309.200 et seq. This permit may be
reopened to include new requirements imposed under these Statutes.
A. (28.) COMPLIANCE BOUNDARY
[15A NCAC 02L.0107]
The compliance boundary for the disposal system shall be specified in accordance with 15A NCAC 02L .0107(a) or
(b) dependent upon the date permitted. An exceedance of groundwater standards at or beyond the compliance
boundary is subject to remediation action according to 15A NCAC 02L .0106(c), (d), or (e) as well as enforcement
actions in accordance with North Carolina General Statute 143-215.6A through 143-215.6C. The compliance
boundary map for this facility is incorporated herein and attached hereto as Attachment A.
Page 25 of 25

Il �}�t<< - �l J `� �..,- iia, �:��^. 5,�= ��'�i �� Z� tyE, �, � .�.fr •� '" :.� J � ; � --
t Lam``_ • r \ .�
Rk
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Duke Energy Corporation
Allen Steam Station
Map not to scale
iteGridlQuad:
G14NFJBelmont Permitted Flow:
Not limited
:ceivine Streams:
Catawba and South Fork Catawba Rivers
ream Class:
WS-IV B & WS-V B 8-Dii.it HUC
03050102
ainate Basin:
Catawba River Basin Sub -Basin:
03-08-34
titude (0011:
35` 11' 23" N Longitude (001):
81' 00' 45" W
titude (002):
35' 10' 30" N Longitude (002):
81° 00' 23" W
Facility
titude (002A):
35' 11' 34" N Longitude 002A;
81° 00' 22" W
,
titude(002B):
35'11'36"N Loneitude(002B):
81°00'30" W
Location
titude {003):
350 11' 23" N Longitude (003):
81 ° 00' 45" W
titudel004):
35' 11' 35" N Longitude (004):
81° 00' 22" W
titude (0061:
350 10' 50" N Longitude (006):
81' 00' 49" W
NPDES Permit No. NC0004979
titude (007):
35' 11' 55" N Longitude (007):
81° 00' 36" W
North
Gaston County
ititude (008):
35' 10' 55" N Longitude (008):
81° 00' 24" W

Attachment A
NOTES: %` f a
1USAMPLELOCATIONS WERE DERNEOFROM VARIOUS
SOURCESANDARE A MIX OF SUINEYEDAND '
APPROXIMATE LOCATIONS. THEREFORE, SAMPLE 4
LOCATIONS ME TO BE DEENEDAPPRO%SIAIE. 1 4 f '•�
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LEGEND
AM 2p0 n top BOp
ACTNEASH BASIN WASTE BOUNDARY
NACTNE ASH BASIN NNSTE BOUNDARY
• ASH BASIN COMPLIANCE BOUNDARY
G5tWr5[xT h,EET
Stg NJJFn 81SD:[fMREaSO
LANDFILLBOUNDARYLANBOUNDARY
Gp@1NLLE.8o111H GAOMNAgBp1
Pnaxeeeaou-ease
AM STORAGE ANDSTRUCTURAL FILL BOUNDARY
Tema
�pgerter�U�ux�o xe u p" m.1A!+Ar•
PIAHTSDE BOUNDARY
a¢'m er°�oA.rq
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ACTNE
ASH BASIN
T�h
FIGURE 7
ASH BASIN WASTE AND
COMPLIANCE BOUNDARIES
ALLEN STEAM STATION
DUKE ENERGY CAROLINAS, LLC
BELMONT, NORTH CAROLINA