NC0004987_Permit (Issuance docs)_20200901

July 6, 2020
MEMORANDUM
To: Clinton Cook, Regional Engineer
NC DEQ / DWR / Public Water Supply Section
Mooresville Regional Office
From: Sergei Chernikov, Environmental Engineer III, Industrial NPDES Permitting
Unit, Division of Water Resources ([e-mail])
Subject: Review of the discharge locations for the following Draft NPDES Major
Modification:
NC0004987 Marshall Steam Station
Catawba County
Please indicate below by August 12, 2020 your agency's position or viewpoint on the facility
listed above. We cannot issue the permit without your concurrence. Please return this form
at your earliest convenience.
RESPONSE:
This agency has reviewed the draft permit and determined that the proposed
discharge will not be sufficiently close to any existing or known proposed
public water supply intake so as to create an adverse effect on water quality.
We concur with the issuance of this permit provided the facility is operated
and maintained properly, the stated effluent limits are met prior to discharge,
and the discharge does not contravene the designated water quality standards.
Concurs with issuance of the above permit,
are met *
* I have no appreciable expertise in implementation of the Clean Water Act
requirements and have minimal understanding of the information provided. As
a result, I have no basis for opposing the permit.
Opposes the issuance of the above permit, based on reasons stated below, or
attached:
t/
Signed o , Date: August 14.2020
cc: file

The Mooresville Tribune
Advertising Affidavit
PO Box 968
Hickory, NC 28603
NCDENR DIVISION OF WATER RESOURCES
ATTN: ACCOUNTS PAYABLE
1611 MAIL SERVICE CENTER
RALEIGH, NC 27699-1611
Account Number
3657135
Date
July 12, 2020
Date Category Description Ad Number Ad Size
07/12/2020 Legal Notices PUBLIC NOTICE N.C. DEPARTMENT OF ENVIRONMENTAL 0000660392 2 x 33 L
THIS IS NOT A BILL.
Publisher of
The Mooresville Tribune
Iredell County
Before the undersigned, a Notary Public of Iredell County, North Carolina, duty
commissioned, qualified, and authorized by law to administer oaths, in said
County and State; that he/she is authorized to make this affidavit and sworn
statement; that the notice or other legal advertisement, a copy of which is attached
hereto, was published in the The Mooresville Tribune on the following dates:
07/12/2020
and that the said newspaper in which such notice, or legal advertisement was
published, was a newspaper meeting all the requirements and qualifications of
Section 1-597 of the General Statutes of North Carolina.
Assistant Bookkeeper
Newspaper reference: 0000660392
/Swwom to and subscribed before me, this _ f q day of _"mil, , 2020
Notary Public
r
Notary public _
lrea'ell County
My Commission expires: hl. 24 3:7 JW2 2
PLEASE PAY FROM INVOICE. THANK YOU �'rrtt m1w'•\`\�

PUBLIC NOTICE
N.C. DEPARTMENT OF ENVIRONMENTAL QUALITY INTENT TO ISSUE
NPDES WASTEWATER DISCHARGE PERMIT #NCOftMM
Public comment or objection to the draft permit modification is invited.
All comments received by August 12, 2020 will be considered in the final
determination regarding permit issuance and permit provisions.
PERMIT APPLICATION
Duke Energy Progress, LLC, 526 South Church St., Charlotte, N.C., has ap-
plied for modification of its NPDES wastewater permit (NC0004987) for
Marshall Steam Station, 8320 E. NC Highway 150, Terrell, Catawba Coun-
ty. The facility discharges treated industrial wastewater, groundwater,
and stormwater to the Catawba River in the Catawba River basin. Some
of the parameters are water quality limited. This discharge may affect fu-
ture allocations in this portion of the Catawba River basin. The location of
Outfall is: Latitude: 35036'21"; Longitude: 80057'35".
The draft wastewater permit modification and related documents are
available online at: https://goo.ol/3WtzME Printed copies of the draft per-
mit and related documents may be reviewed at the department's
Mooresville Regional Office. To make an appointment to review the docu-
ments, please call 704-663-1699.
Public comment on the draft permit modification should be mailed to:
Wastewater Permitting, 1617 Mail Service Center, Raleigh, N.C., 27699-
1617. Public comments may also be submitted by email to:
p ubliccomments@ncdenr.g ov.
Please be sure to include "Marshall" in the email's subject line.
Publish: July 12, 2020.

Advertising Affidavit
Observer News Enterprise
309 N College Ave
Newton, NC 28658
NCDENR
Wren Thedford
1617 Mail Service Center
Raleigh, NC 27699-1617
Date Description Charge
07/09/20 Intent to issue wastewater permit $88.00
#NC0004987; Duke Energy at
Marshall Steam Station
North Carolina
Catawba County
Balance
$88.00
Philip Rogers, BEING DULY SWORN SAYS: that he is the Composing Manager for the
OBSERVER NEWS ENTERPRISE, a newspaper published at Newton, North Carolina. It is a
newspaper of general circulation in Catawba County and surrounding counties. The Notice of
Intent to Issue Wastewater Permit #NC0004987; Duke Energy for Marshall Steam Station,
was published in said newspaper and not a supplement thereof and is a true copy of the
Notice as it was published in the regular and entire edition, beginning on July 9, 2020, and
that said OBSERVER NEWS ENTERPRISE was regularly distributed to the subscribers
during said period.
Sworn to and subscribed before me this the 1 try y of July, 2020.
Composing Mana er:
;t•'
NOTARY PUBLIC:
My Commission Expires:.2

PUBLIC NOTICE
N.C. DEPART-
MENT OF ENVI-
RONMENTAL
QUALITY IN-
TENT TO ISSUE
NPDES WASTE-
WATER DIS-
CHARGE PER-
MIT #NC0004987
Public comment
or objection to the
draft permit modi-
fication is invited.
All comments re-
ceived by August
12. 2020 will be
considered in the
final determina-
tion regarding
Permit issuance
and permit provi-
sions.
PERMIT APPLI-
CATION
Duke Energy
Progress, LLC,
526 South
Church St., Char-
lotte, N.C., has
applied for modifi-
cation of its
NPDES wastewa-
ter permit
(NC0004987) for
Marshall Steam
Station, 8320 E.
NC Highway 150,
Terrell, Catawba
County. The fa-
cility discharges
treated industrial
wastewater,
groundwater, and
stormwater to the
Catawba River in
the Catawba Riv-
er basin. Some of
the parameters
are water quality
limited. This dis-
charge may affect
future allocations
in this portion of
the Catawba Riv-
er basin. The lo-
cation of Outfall
is: Latitude:
35036'21"; Longi-
tude: 80057'35".
[-he draft waste-
water permit
modification and
related docu-
ments are availa-
ble online at:
https://900.gl/3Wt
zMF. Printed cop-
ies of the draft
permit and relat-
ed documents
may be reviewed
at the depart-
ment's Moores-
ville Regional Of-
fice. To make an
appointment to
review the docu-
ments, please
call 704-663-
1699.
Public comment
on the draft per-
mit modification
should be mailed
to: Wastewater
Permitting, 1617
Mail Service Cen-
ter, Raleigh, N.C.,
27699-1617.
Public comments
may also be sub-
mitted by email
to: publiccom-
ments@ncdenr.g
ov. Please be
sure to include
"Marshall" in the
email's subject
line.
Publish: July 9,
2020

ROY COOPER
Governor
MICHAEL S. REGAN.
Secretary
S. DANIEL SMITH
Director
Mr. Paul Draovitch, Senior Vice President
Environmental, Health and Safety
Duke Energy Carolinas, LLC
Mail Code EC13K
P.O. Box 1006
Charlotte, North Carolina 28201-1006
Dear Mr. Draovitch:
NORTH CAROLINA
Environmental Quality
July 6, 2020
Subject: Draft NPDES Major Modification
Permit NC0004987
Marshall Steam Station
Catawba County
Facility Class I
The Division has received your request to increase flow limit to 3.0 MGD for the dewatering
phase (Outfall 002) due to the need to incorporate wastewater from the remediation project. The
request has been granted. Enclosed with this letter is the modified permit. Please review this permit
carefully to ensure thorough understanding of the conditions and requirements it contains.
The draft permit modification contains the following significant changes from your current
permit:
• The flow limit for Outfall 002 (dewatering phase) was increased to 3.0 MGD.
Please provide any comments you have regarding the draft permit to this office by
August 12, 2020. At this time, the Division is also publishing a notice in the newspapers of general
circulation in Catawba County, inviting public comment on the Draft Modification. Following the 30-
day comment period, we will review all pertinent comments received and take appropriate action on
the permit modification.
North Carolina Department of Environmental Quality I Division of Water Resources
512 North Salisbury Street 11617 Mail Service Center I Raleigh, North Carolina 27699-1617
��� 919.707.9000

If you have any questions about the NPDES permit process, please contact me at the
following e-mail address: sergei.chernikov&ncdenr.g(_)y, or telephone number: 919-707-3606.
Sincerely,
Sergei Chernikov, Ph.D.
Environmental Engineer III
Industrial NPDES Permitting Unit
cc: Central Files
NPDES Files
EPA Region IV (e-copy)
Mooresville Regional Office/Water Quality (e-copy)
Mooresville Regional Office/PWS (e-copy)
WSS/Aquatic Toxicology Unit (e-copy)

PERMIT No. NC0004987
STATE OF NORTH CAROLINA
DEPARTMENT OF ENVIRONMENTAL QUALITY
DIVISION OF WATER RESOURCES
Draft PERMIT
TO DISCHARGE WASTEWATER UNDER THE
NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM
In compliance with the provisions 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
Marshall Steam Station
At the intersection of NC Highway 150 and NCSR 1841
Terrell
Catawba County
to receiving waters designated as the Catawba River (Lake Norman) in the Catawba River
Basin in accordance with effluent limitations, monitoring requirements, and other
applicable conditions set forth in Parts I, II, and III hereof.
This modification shall become effective
This permit modification and authorization to discharge shall expire at midnight on
September 30, 2021.
Signed this day
D. Daniel Smith, Director
Division of Water Resources
By Authority of the Environmental Management Commission
Page 1 of 22

PERMIT No. NC0004987
SUPPLEMENT TO PERMIT COVER SHEET
All previous NPDES Permits issued to this facility, whether for operation or discharge
are hereby revoked, and as of this 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:
Continue to discharge:
• Outfall 001: once -through cooling water and intake screen backwash
• Outfall 002: treated wastewater (consisting of metal cleaning wastes, coal
pile runoff, ash transport water, storm water, low volume wastes, landfill
leachate, and FGD wet scrubber wastewater) from the ash settling basin.
• Outfall 005. Upon completion of construction, discharge from the new
lined retention basin. Basin will accept wastes from holding basin (coal
pile runoffl, ash transport water, various sumps, stormwater runoff, FGD
wastewater, and various low volume wastes such as boiler blowdown, oily
waste treatment, wastes/backwash from the water treatment processes,
plant area wash down water, equipment heat exchanger water, landfill
leachate, and ash transport water. Upon completion of construction all
waste streams previously discharged to the ash basin, will be re-routed to
the new retention basin. During the transition period, wastewater from
the ash pond can also be discharged (Outfall 002).
• Outfalls 002A and 00213: yard sump overflows.
• Outfall 007: the emergency spillway of the Ash Pond. 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.
• Internal outfall 001/001A. Yard sump (wastewater from the yard sump 2,
the yard sump 3, the fly ash silo yard sump, and stormwater) discharging
to the retention basin.
• Internal Outfall 003: non -contact cooling water from the induced draft fan
control house to the intake for cooling water pumps.
• Internal Outfall 006: treated FGD wet scrubber wastewater to the new lined
retention basin.
• Internal Outfall 010 from Holding Basin: coal pile runoff, and stormwater
to the retention basin.
From a facility located at Duke Energy's Marshall Steam Station at the
intersection of NC Highway 150 and NCSR 1841 in Terrell, Catawba
County;
2. Discharge from said treatment works at the locations specified on the
attached map into the Catawba River (Lake Norman) which is classified
WS-IV and B CA waters in the Catawba River Basin.
Page 2 of 22

PERMIT No. NC0004987
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 (once -through
cooling water). Such discharges shall be limited and monitored2 by the Permittee as
specified below:
EFFLUENT
DISCHARGE LIMITATIONS
MONITORING REQUIREMENTS
Monthly
Daily
Measurement
Sample
Sample
CHARACTERISTICS
Average
Maximum
Frequency
a
Location
Pump logs or
Flow, MGD
Monitor & Report
Daily
similar
Effluent
Daily
readings
Grab
Temperature
33.3 oC
Effluent
November 1 - June 30
Daily
Effluent
Temperature
Jul 1 - October 31
34.4 oC
Grab
Free Available
Chlorine 1
0.L
2 m g�
0.5 m L
g�
Dail y
Grab
Effluent
NOTES:
1 Once -through cooling water shall not be chlorinated. Should the facility wish to chlorinate
once -through cooling water, Division permission shall be obtained prior to
commencement of chlorination. The monitoring requirement and effluent limitations only
apply if chlorination is commenced.
2 The permittee shall submit Discharge Monitoring Reports electronically using NC
DWR's eDMR application system. Please See Special Condition A. (30.).
There shall be no discharge of floating solids or visible foam in other than trace amounts.
Based upon studies conducted by the permittee and submitted to the Division, it has been
determined pursuant to Section 3.16(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.
Page 3 of 22

PERMIT No. NC0004987
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 settling
basin discharge - 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 by the Permittee as specified below:
EFFLUENT CHARACTERISTICS
DISCHARGE LIMITATIONS
MONITORING REQUIREMENTS
Monthly Daily
Averagre Maximum
Measurement Sample
Fre uenc Type
Sample
Location'
Flow, MGD
Oil and Grease
Total Suspended Solids2
Monitor & Report
9.0 mg/L 12.0 mg/L
20.0 mg/L 50.0 mg/L
Weekly
Monthly
Monthly
Weekly
Pump logs
or similar
readings
Grab
Grab
Grab
Effluent
Effluent
Effluent
Total Arsenic
Effluent
Total Copper
1.0 mg/L3
1.0 mg/L3
Weekly
Grab
Effluent
Total Iron
1.0 mg/L3
1.0 mg/L3
Weekly
Grab
Effluent
Total Mercury6
Weekly
Grab
Effluent
Total Selenium
Weekly
Grab
Effluent
Turbiditys, NTU
Monthly
Grab
Effluent
Effluent
Nitrate/nitrite as N, mg/L
Quarterly Grab
Bromide, mg/L
Monthly
Monthly
Grab
Grab
Effluent
Total Hardness, mg/L
Effluent
Total Nitrogen
NO2+NO3+TKN , m L
Monitor & Report
Monitor & Report
See Part I, Section A. (18.)
Quarterly
Quarterly
Monthly
Grab
Grab
Grab
Effluent
_
Effluent
Total Phosphorus, mg/L
Chronic Toxicity
Effluent
Effluent
pH7
Between 6.0 and 9.0 Standard Monthly Grab
Units
NOTES:
1 Effluent sampling shall be conducted at the discharge from the ash settling basin prior to
mixing with any other waste stream(s).
2 The facility shall continuously monitor TSS concentration when the decanting process
commences and the decanting pump shall be shut off 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
only required when the pumps are employed for decanting.
3 The limits for total copper and total iron only apply when chemical metal cleaning
wastewaters are being discharged.
4 The permittee shall submit Discharge Monitoring Reports electronically using NC DWR's
eDMR application system. Please See Special Condition A. (30.).
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
Page 4 of 22

PERMIT No. NC0004987
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 use EPA method 1631E.
7 The facility shall continuously monitor pH when the decanting process commences and the
decanting pump shall be shut off automatically when 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 only required when the pumps are employed for 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.
There shall be no discharge of floating solids or visible foam in other than trace amounts.
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 station 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.
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"). This requirement only applies to bottom ash transport water generated
after 12/31/2019 or a new date as HB630 may be amended.
By November 1, 2021 there shall be no discharge of pollutants in bottom ash transport
water. This requirement only applies to bottom ash transport water generated after
November 1, 2021. Beginning on November 1, 2021, the permittee will comply with the
Steam Electric Effluent Limitations Guidelines for bottom ash wastewater (40 C.F.R.
423) in effect on December 1, 2020.
The limits and conditions in Section A. (3.) of the permit apply when water in the ash
settling basin is lowered below the three feet trigger mark. The facility shall notify DWR
Complex NPDES Permitting Unit and DWR Mooresville Regional Office, in writing, seven
calendar days prior to the commencement of the decanting.
Page 5 of 22

PERMIT No. NC0004987
A. (3.) Effluent Limitations and Monitoring Requirements (Outfall 002 -
dewatering phase)
[15A NCAC 02B .0400 et seq., 02B .0500 et seq.]
During the period beginning on the commencement date of the dewatering operation
and lasting until expiration, the Permittee is authorized to discharge from Outfall 002
Ash Settling Basin Discharge (Dewatering - removing the interstitial water). Such
discharges shall be limited and monitored4 by the Permittee asspecified below:
EFFLUENT CHARACTERISTICS
DISCHARGE LIMITATIONS
MONITORING REQUIREMENTS
Monthly
—Average
Daily
Maximum
Measurement
Frequency
Sample
Type
Sample
Location'
Flow
3.0 MGD
12.0 mg/L
Weekly
Pump logs
or similar
readings
Effluent
Oil and Grease
9.0 mg/L
Monthly
Grab
Effluent
Total Suspended SolidS2
20.0 mg/L
50.0 mg/L
Monthly
Grab
Effluent
Total Arsenic
139.1 µg/L
695.4 µg/L
Weekly
Grab
Effluent
Total Copper
1.0 mg/L3
1.0 mg/L3
Weekly
Grab
Effluent
Total Iron
1.0 mg/L3
1.0 mg/L3
Weekly
Grab
Effluent
Total Mercury6
Weekly
Grab
Effluent
Total Selenium
Weekly
Grab
Effluent
Turbidity5, NTU
Monthly
Grab
Effluent
Nitrate/nitrite as N, mg/L
Quarterly
Grab
Effluent
Bromide, mg/L
Monitor & Report
Monthly
Grab
Effluent
Total Hardness, mg/L
Monthly
Grab
Effluent
Total Nitrogen
NO2+NO3+TKN , m L
Quarterly
Quarterly
Grab
Grab
Effluent
Effluent
Total Phosphorus, mg/L
Monitor & Report
Chronic Toxicity
See Part I, Section A. (18.)
Monthly
Grab
Effluent
pH7
Between 6.0 and 9.0 Standard
Units
Monthly
Grab
Effluent
NOTES:
1 Effluent sampling shall be conducted at the discharge from the ash settling basin prior to
mixing with any other waste stream(s).
2 The facility shall continuously monitor TSS concentration when the dewatering process
commences and the dewatering pump shall be shut off 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 only required when the pumps are employed for dewatering.
3 The limits for total copper and total iron only apply when chemical metal cleaning
wastewaters are being discharged.
4 The permittee shall submit Discharge Monitoring Reports electronically using NC
DWR's eDMR application system. Please See Special Condition A. (30.).
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 213 .0211 (21)).
Page 6 of 22

PERMIT No. NC0004987
NTU - Nephelometric Turbidity Unit.
6 The facility shall use EPA method 1631E.
7 The facility shall continuously monitor pH when the dewatering process commences
and the dewatering pump shall be shut off automatically when 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 only required when the pumps are employed for 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.
There shall be no discharge of floating solids or visible foam in other than trace amounts.
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.
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.
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"). This requirement only applies to bottom ash transport water generated
after 12/31/2019 or a new date as HB630 may be amended.
By November 1, 2021 there shall be no discharge of pollutants in bottom ash transport
water. This requirement only applies to bottom ash transport water generated after
November 1, 2021. Beginning on November 1, 2021, the permittee will comply with the
Steam Electric Effluent Limitations Guidelines for bottom ash wastewater (40 C.F.R.
423) in effect on December 1, 2020.
The facility shall notify DWR Complex NPDES Permitting Unit and DWR Mooresville
Regional Office, in writing, seven calendar days prior to the commencement of the
dewatering.
Page 7 of 22

PERMIT No. NC0004987
A. (4.) Effluent Limitations and Monitoring Requirements (Outfal1002A)
[ 15A NCAC 02B .0400 et seq., 02B .0500 et seq.]
During the period beginning on the effective date of this permit and lasting until
expiration, the Permittee is authorized to discharge from Outfall 002A (yard sump # 1
overflows). Such discharges shall be limited and monitored2 by the Permittee as
s ecified below:
EFFLUENT
DISCHARGE LIMITATIONS
MONITORING REQUIREMENTS
Monthly
Daily
Measurement
Sample
Sample
CHARACTERISTICS
Avera a
Maximum
Frequency
Type
Location'
Flow, MGD
Per discharge
Estimate
Effluent
event
pH
Between 6.0 and 9.0 Standard
Per discharge
Grab
Effluent
Units
event
30.0 mg/L
100.0 mg/L
Per discharge
Total Suspended Solids
Grab
Effluent
event
Oil and Grease
15.0 mg/L
20.0 mg/L
I Per dischargeGrab
Effluent
event
Total Iron, mg/L
Per discharge
Grab
Effluent
event
NOTES:
1 Effluent samples shall be collected at a point upstream of the discharge to the Catawba River.
2 The permittee shall submit Discharge Monitoring Reports electronically using NC DWR's
eDMR application system. Please See Special Condition A. (30.).
There shall be no discharge of floating solids or visible foam in other than trace amounts.
All flows shall be reported on monthly DMRs. Should no flow occur during a given
month, the words "No Flow" shall be clearly written on the front of the DMR. All samples
shall be of a representative discharge.
Page 8 of 22

PERMIT No. NC0004987
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 (yard sump #2
overflows). Such discharges shall be limited and monitored2 by the Permittee as
specified below:
DISCHARGE LIMITATIONS
MONITORING REQUIREMENTS
EFFLUENT
CHARACTERISTICS
Monthly
Daily
Measurement
Sample
Sample
Avera a
Maximum
Frequency
Type
Location'
Flow, MGD
Per discharge
Estimate
Effluent
event
_
pH
Between 6.0 and 9.0 Standard
Per discharge
Grab
Effluent
Units
30.0 mg/L 100.0 mg/L
event
Total Suspended Solids
Per discharge
Grab
Effluent
event
_
Oil and Grease
15.0 mg/L
20.0 mg/L
Per discharge
Grab
Effluent
event
Total Iron, mg/L
Per discharge
Grab
Effluent
event
NoTEs•
1 Effluent samples shall be collected at a point upstream of the discharge to the Catawba River.
2 The permittee shall submit Discharge Monitoring Reports electronically using NC DWR's
eDMR application system. Please See Special Condition A. (30.).
There shall be no discharge of floating solids or visible foam in other than trace amounts.
All flows shall be reported on monthly DMRs. Should no flow occur during a given
month, the words "No Flow" shall be clearly written on the front of the DMR. All samples
shall be of a representative discharge.
Page 9 of 22

PERMIT No. NC0004987
A. (6.) Effluent Limitations and Monitoring Requirements (Internal 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 Internal Outfall 003 (non -
contact cooling water from the induced draft fan control house). Such discharges
shall be limited and monitored2 by the Permittee as specified below:
EFFLUENT
DISCHARGE
LIMITATIONS
MONITORING REQUIREMENTS
Monthly
Daily
Measurement
Sample
Sample
CHARACTERISTICS
Averse
Maximum
Fre uenc
Type
Location
Flow, MGD
Semi-annually
Estimate
Effluent
Temperature, oC
Semi-annually
Grab
Effluent
Total Residual
Semi-annually
Grab
Effluent
Chlorine', µ L
0.2 m g/L 0.5 m g/L
Free Available
Semi-annually
Grab
Effluent
Chlorine'
Between 6.0 and 9.0 Standard
Semi-annually
Grab
Effluent
pH
Units
NoTEs-
1 Monitoring requirements apply only if chlorine is added to the cooling water. Neither free
available chlorine nor total residual chlorine may be discharged from any unit for more than
two hours in any one day and not more than one unit in any plant may discharge free
available chlorine or total residual chlorine at any one time.
2 The permittee shall submit Discharge Monitoring Reports electronically using NC DWR's
eDMR application system. Please See Special Condition A. (30.).
There shall be no discharge of floating solids or visible foam in other than trace amounts.
Limitations shall be met at the discharge point.
Page 10 of 22

PERMIT No. NC0004987
A. (7.) Effluent Limitations and Monitoring Requirements (Internal Outfall 006)
[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 Internal Outfall 006 (treated
FGD wet scrubber wastewater to retention basin). Such discharges shall be limited
and monitored2 by the Permittee as specified below:
EFFLUENT
DISCHARGE LIMITATIONS
MONITORING REQUIREMENTS
Monthly
Daily
Measurement
Sample
Sample
CHARACTERISTICS
Avera a
Maximum
Fre uency
Type
Location'
Pump logs or
Flow, MGD
Monitor & Report
Monthly
similar
Effluent
readings
Grab
Effluent
Total Arsenic
8.0 µg/L4
11.0 µg/L4
Quarterly
356.0 ng/L4
788.0 ng/L4
Quarterly
Grab
Total Mercury3, ,ng/L
Effluent
Total Selenium
12.0 pg/L4
23.0 pg/L4
Quarterly
Grab
Effluent
Nitrate/nitrite as N
4.4 mg/L4
17.0 mg/L4
Quarterly
Grab
Effluent
pH
Between 6.0 and 9.0 Standard
Quarterly
Grab
Effluent
Units
NOTES:
1 Sample Location: E - Effluent samples shall be collected prior to the commingling with
other waste streams.
2 The permittee shall submit Discharge Monitoring Reports electronically using NC
DWR's eDMR application system. Please See Special Condition A. (30.).
3 The facility shall use EPA method 1631E.
4 Beginning on November 1, 2021, the permittee shall comply with the Steam Electric
Effluent Limitations Guidelines for FGD wastewater (40 C.F.R. 423) in effect on December
1, 2020.
All flows shall be reported on monthly DMRs. Should no flow occur 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.
Page 11 of 22

PERMIT No. NC0004987
A. (8.) EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS (Outfall 005)
[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 005 - Retention
Basin discharge. Such discharges shall be limited and monitored' by the Permittee as
specified below:
EFFLUENT CHARACTERISTICS
DISCHARGE LIMITATIONS
MONITORING REQmRzmENTs
Monthly
Average
Daily
Maximum
Measurement Sample Sample
Fre uenc 2 e Location
Flow, MGD
Weekly
Instantaneous
or Estimate
Effluent
pH
Between 6.0 and 9.0
standard units
Monthly
Grab
Effluent
TSS
30.0 mgjL
50.0 m L
Monthly
Grab
Effluent
Oil and Grease
15.0 m L
20.0 m L
Monthly
Grab
Effluent
Fluoride, m L
Monthly
Grab
Effluent
Total Mercu 2, n L
Monthly
Grab
Effluent
Total Silver, µ L
Monthly
Grab
Effluent
Total Iron3
1.0 m L
1.0 m L
Monthly
Grab
Effluent
Total Zinc, µ L
Monthly
Grab
Effluent
Total Arsenic,µ L
Month'
Grab
Effluent
Total Cadmium, L
Monthly
Grab
Effluent
Total Chromium, µ L
Monthly
Grab
Effluent
Total Co era
68.8 µ L
76.8 µ L
Monthly
Grab
Effluent
Total Lead, µ L
Monthly
Grab
Effluent
Total Nickel, µ L
Monthly
Grab
Effluent
Total Selenium, µ L
Month'
Grab
Effluent
Total Nitrogen
NO2 + NO3 + TKN , m L
Quarterly
Grab
Effluent
Total Phosphorus, m L
Quarterly
Grab I
Effluent
Sulfates, m L
Monthly
Grab
Effluent
Chlorides, m L
Monthly
Grab
Effluent
Bromide, m L
Monthly
Grab
Effluent
TDS, m L
Monthly
Grab
Effluent
Total Hardness, m L
Monthly
Grab
Effluent
Temperature, OC
Monthly
Grab
Effluent
Conductivity, pmhocm
Monthly
Grab
Effluent
Chronic Toxicit 4
Monthly
Grab
Effluent
Notes:
1. The permittee shall submit Discharge Monitoring Reports electronically using NC
DWR's eDMR application system. Please See Special Condition A. (30.).
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 23.0%, see Special Condition A. (18.).
The facility shall submit EPA Form 2C for Outfall 005 no later than 180 days
from the commencement of the discharge. The facility shall notify DWR/NPDES
Complex Permitting, in writing, 30 days prior to the commencement of the
discharge from this outfall.
There shall be no discharge of floating solids or visible foam in other than trace amounts.
Page 12 of 22

PERMIT NO. NC0004987
A. (9.) 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 ash basin. Such discharges shall be limited and monitored' by the
Permittee as specified below:
EFFLUENT CHARACTERISTICS
DISCHARGE
LIMITATIONS
MONITORING REQUIREMENTS
Monthly
Average
Daily
MaximumL
Measurement
Fre uenc
Sample
Type
Sample
Location
Flow, MGD
Waived
1 Estimate
I Effluent
H
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 Catawba
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. (10.) EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS (Internal
Outfall 010)
[15A NCAC 02B .0400 et seq., 02B .0500 et seq.]
During the period beginning upon commencement of operation of the yard sump and
lasting until expiration, the Permittee is authorized to discharge from Internal outfall
010 - Coal yard runoff and stormwater. Such discharges shall be limited and
monitored' by the Permittee asspecified below:
EFFLUENT CHARACTERISTICS
DISCHARGE
LIMITATIONS
MONITORING REQUIREMENTS
Monthly
Average
Daily
Maximum
Measurement Sample
Frequency Type
Sample
Location
Flow, MGD
Quarterly
Estimate
Effluent
H
Quarterly
Grab
Effluent
TSS
Quarterly
Grab
Effluent
Oil and Grease
Quarterly
Grab
Effluent
Notes:
1. The permittee shall submit Discharge Monitoring Reports electronically using
NC DWR's eDMR application system. Please See Special Condition A. (30.).
Page 13 of 22

PERMIT No. NC0004987
A. (11.) 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
122.416)).
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 42 3. 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.
A. (12.) TOXICITY RE -OPENER CONDITION
[NCGS 143-215.3 (a) (2) and NCGS 143-215.66]
This permit shall be modified, or revoked and reissued to incorporate toxicity limitations and
monitoring requirements in the event toxicity testing or other studies conducted on the effluent
or receiving stream indicate that detrimental effects may be expected in the receiving stream as
a result of this discharge.
A. (13.) APPLICABLE STATE LAW (STATE ENFORCEABLE ONLY)
[NCGS 143-215.1(b)]
This facility shall meet the General Statute requirements under NCGS § 130A-309.200 et seq.
This permit may be reopened to include new requirements imposed under these Statutes.
A. (14.) POLYCHLORINATED BIPHENYL COMPOUNDS
[40 CFR 423]
There shall be no discharge of polychlorinated biphenyl compounds such as those commonly
used for transformer fluid.
A. (15.) 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
Page 14 of 22

PERMIT No. NC0004987
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. (16.) INTAKE SCREEN BACKWASH
[NCGS 143-215.1 (b)]
Continued intake screen backwash discharge and overflow from the settling basin are permitted
without limitations or monitoring requirements.
A. (17.) BEST MANAGEMENT PRACTICES
[NCGS 143-215.1 (b)]
It has been determined from information submitted that the plans and procedures in place at
Marshall Steam Station are equivalent to that of a Best Management Practice (BMP).
A. (18.) CHRONIC TOXICITY PASS/FAIL PERMIT LIMIT — OUTFALL 002 AND OUTFALL 005
[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.23.0% for
decanting (Outfall 002) and Outfall 005, and 2.6% for dewatering (Outfall 002).
The permit holder shall perform at a minimum, monthlu 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 monthly test procedure 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
Page 15 of 22

PERMIT No. NC0004987
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 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. (19.) ASH SETTLING BASIN
[NCGS 143-215.1 (b)]
Beginning on the effective date of this permit and lasting until expiration, there shall be no
discharge of plant wastes to the ash pond unless the permittee provides and maintains at all
times a minimum free water volume equivalent to the sum of the maximum 24-hour plant
discharges plus all direct rainfall and all runoff flows to the pond resulting from a 10-year, 24-
hour rainfall event, when using a runoff coefficient of 1.0.
During the term of the permit, the permittee shall remove settled material from the ponds or
otherwise enlarge the available storage capacities in order to maintain the required minimum
volumes at all times. Annually the permittee shall determine and report to the permit issuing
authority: (1) the actual free water volume of the ash pond, (2) physical measurements of the
dimensions of the free water volume in sufficient detail to allow validation of the calculated
volume, and (3) a certification that the required volume is available with adequate safety factor
to include all solids expected to be deposited in the ponds for the following year. Any changes to
plant operations affecting such certification shall be reported to the Director within five days of
the change.
NOTE: In the event that adequate volume has been certified to exist for the term of the permit,
periodic certification is not needed.
A. (20.) CHEMICAL METAL CLEANING WASTES
[40 CFR 4231
It has been demonstrated that under certain conditions it is possible to reduce the concentration
of metals in boiler cleaning wastes in the range of 92 to 99+ percent by. treatment in ash ponds.
Because of dilution problems, and the existence of boundary interface layers at the extremities
of the plume, it is difficult to prove beyond doubt that the quantity of iron and copper discharged
will always be less than one milligram per liter times the flow of metal cleaning when treated in
this manner.
The application of physical/chemical methods of treating wastes has also been demonstrated to
be effective in the treatment of metal cleaning wastes. However, the effectiveness of ash pond
Page 16 of 22

PERMIT No. NC0004987
treatment should be considered in relation to the small differences in effluent quality realized
between the two methods.
It has been demonstrated that the presence of ions of copper, iron, nickel, and zinc in the ash
pond waters was not measurably increased during the ash pond equivalency demonstration at
the Duke Energy's Marshall Steam Station. Therefore, when the following conditions are
implemented during metal cleaning procedures, effective treatment for metals can be obtained
at this facility:
(1) Large ash basin providing potential reaction volumes.
(2) Well-defined shallow ash delta near the ash basin influent.
(3) Ash pond pH of no less than 6.5 prior to metal cleaning waste addition.
(4) Four days retention time in ash pond with effluent virtually stopped.
(5) Boiler volume less than 86,000 gallons.
(6) Chemicals for cleaning to include only one or more of the following:
(a) Copper removal step- sodium bromate, NaBr03i ammonium carbonate, (NH4)2CO3; and
ammonium hydroxide, NH40H.
(b) Iron removal step -hydrochloric acid, HCl; and ammonium bifluoride, (NH4)BF2 and
proprietary inhibitors.
(7) Maximum dilution of wastes before entering ash pond 6 to 1.
(8) After treatment of metal cleaning wastes, if monitoring of basin effluents as required by the
permit reveals discharges outside the limits of the permit, the permittee will re -close the
basin discharge, conduct such in -basin sampling as necessary to determine the cause of
nonconformance, will take appropriate corrective actions, and will file a report with EPA
including all pertinent data.
A. (21.) FLOATING MATERIALS
[NCGS 143-215.1 (b)]
The Permittee shall report all visible discharges of floating materials, such as an oil sheen, to the
Director when submitting DMRs.
A. (22.) CHEMICAL DISCHARGES
[NCGS 143-215.1 (b)]
Discharge of any product registered under the Federal Insecticide, Fungicide, and Rodenticide
Act to any waste stream which may ultimately be released to lakes, rivers, streams or other
waters of the United States is prohibited unless specifically authorized elsewhere in this permit.
Discharge of chlorine from the use of chlorine gas, sodium hypochlorite, or other similar
chlorination compounds for disinfection in plant potable and service water systems and in
sewage treatment is authorized. Use of restricted use pesticides for lake management purposes
by applicators licensed by the N.C. Pesticide Board is allowed.
A. (23.) PRIORITY POLLUTANT ANALYSIS - OUTFALL 002
[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 outfall 002 and submit the results with the application for permit
renewal.
A. (24.) WAIVERS
[NCGS 143-215.1 (b)]
Page 17 of 22

PERMIT No. NC0004987
Nothing contained in this permit shall be construed as a waiver by permittee or any right to a
hearing it may have pursuant to State or Federal laws or regulations.
A. (25.) STRUCTURAL INTEGRITY INSPECTIONS OF ASH POND DAM
[15A NCAC 02K.0208]
The facility shall meet the dam design and dam safety requirements per 15A NCAC 2K.
A. (26.) 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 180 days prior to permit
expiration. 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.
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
1621 Mail Service Center
Raleigh, NC 27699-1621
A. (27.) CLEAN WATER ACT SECTION 316 (B)
140 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 with the next renewal
application.
Page 18 of 22

PERMIT No. NC0004987
A. (28.) FISH TISSUE MONITORING NEAR ASH POND DISCHARGE - OUTFALL 002
[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 the monitoring is to evaluate potential uptake of
pollutants by fish tissue near the Ash Pond discharge. The parameters analyzed in fish tissue
shall be arsenic, selenium, and mercury. The monitoring shall be conducted in accordance with
the Sampling Plan approved by the Division. 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
1621 Mail Service Center
Raleigh, NC 27699-1621
A. (29.) INSTREAM MONITORING
115A NCAC 02B.0500 ET SEQ.]
The facility shall conduct monthly instream monitoring (approximately one mile upstream and
approximately one mile downstream of the ash pond discharge) for total arsenic, total selenium,
total mercury, total chromium, dissolved lead, dissolved cadmium, dissolved copper, dissolved
zinc, total bromide, total hardness (as CaCO3), turbidity, and total dissolved solids (TDS). The
monitoring results shall be reported on the facility's Discharge Monitoring Reports and included
with the NPDES permit renewal application. This condition becomes effective on June 1 2018.
A. (30.) 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
• Section D. (2.) Reporting
• Section D. (6.) Records Retention
• Section E. (5.) Monitoring Reports
Page 19 of 22

PERMIT No. NC0004987
1. ReRortigg Requirements fSupersedes Section D. 2. and Section E. 5. a
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)].
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:
Page 20 of 22

PERMIT No. NC0004987
https:/ lwww.federalrepister.pov/documents/20l5/ 10/22/2015-24954/national-pollutant-
discharge-elimination-system-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://deg.nc.gov/about/divisionslwater-resources/­edmr
4. Sianatory Requirements [Supplements Section B. (11.1 ibl and Supersedes Section B.
11.(djj
All eDMRs submitted to the permit issuing authority shall be signed by a person described
in Part II, Section B. (11.)(a) or by a duly authorized representative of that person as
described in Part II, Section B. (11.)(b). A person, and not a position, must be delegated
signatory authority for eDMR reporting purposes.
For eDMR submissions, the person signing and submitting the DMR must obtain an eDMR
user account and login credentials to access the eDMR system. For more information on
North Carolina's eDMR system, registering for eDMR and obtaining an eDMR user account,
please visit the following web page:
http: LIdeg.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 122.22]. NO OTHER STATEMENTS OF
CERTIFICATION WILL BE ACCEPTED:
"I certify, under penalty of law, that this document and all attachments were prepared under
my direction or supervision in accordance with a system designed to assure that qualified
personnel properly gather and evaluate the information submitted. Based on my inquiry of
the person or persons who manage the system, or those persons directly responsible for
gathering the information, the information submitted is, to the best of my knowledge and
belief, true, accurate, and complete. I am aware that there are significant penalties for
submitting false information, including the possibility of fines and imprisonment for knowing
violations. "
Page 21 of 22

PERMIT No. NC0004987
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].
A. (31.) 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.
Page 22 of 22

Marshall Steam Station
2014 Freshwater RPA -
95% Probabilityl95% Confidence
Outfall 002 Dewatering 1
NC0004987
MAXIMUM DATA POINTS = 58
Qw = 3 MGD
Qw (MGD) = 3.00
WWTP/WTP Class:
1Q10S (cfs) = 49.15
IWC @ 1Q10S = 8.64%
7Q10S (cfs) = 60.00
1WC @ 7Q10S = 7.19%
7Q10W (cfs) = 60.00
IWC @ 7Q10W = 7.19%
30Q2 (cfs) = 60.00
IWC @ 30Q2 = 7.19%
Avg. Stream Flow, QA (cfs) = 60.00
IWC @ QA = 7.19%
Receiving Stream: Lake Norman
Stream Class: WS-IV
PARAMETER
STANDARDS & CRITERIA (2)
TYPE
REASONABLE POTENTIAL RESULTS
F
RECOMMENDED ACTION
(1) NC WQS /
Applied '/2 FAY /
j
Max Pred
Chronic
Standard Acute
11 # Det. Cw Allowable Cw
Acute: NO WQS
Arsenic
C 50
FW(7Q10s)
ug/L
1 1 3,560.0
add limit
Vote: n 5 9 Default C.V. Chronic: 695.4
— —
Limited data set > All_owa_ble C_w_
Arsenic
C 10
ffH/WS(Qavg)
ug/L
.1-value(s) _
1 1 3,560.0 Chronic: 139.1
_ _ _ _ _
_ _ _ _ _ _ — —
Note: n < 9 Default C.V. 1 value(s) > Allowable Cw
Cadmium
NC 2
FW(7Q10s) 15
ug/L
1 0 0.5 Acute: 173.E
no limit
Note: n 5 9 Default C.V. -Chronic: 27.8
— — —-------
Limited data set No oaluc = Allowable Cw
Chlorides (AL)
NC 230
FW(7Q lOs)
mg/L
Acute: NO WQS
8
1 1rDeautC.V.
no limit
_ _ _ _ _ _ _ _
Note: n <_ 9 Chronic: 3,199
— —
Limited data set NO value =• Allowable Cw
Chromium
NC 50
FW(7Q10s) 1022
uglL
Acute: 11,828.7
1 0 0.5
no limit
Note: n < 9 Default C.V. Chronic: 695.4
— — —
Limited data set No value > Allowable Ca
Copper (AL)
NC 7
FW(7QlOs) 7.3
ug/L
Acute: 84.5
1 1 2.0
no limit
_ _ _ _ _
Note: n<9 Default C.V. Chronic: 97.4
-------
Limited data set No value > Allowable Cw
Fluoride
NC 1800
FW(7Q10s)
ug/L
1 1 2.8 Acute: NO WQSno
limit
Note: n 5 9 Default C.V. Chronic: 25,034.8
— —
Limited data set No value> Allowable c to
Lead
NC 25
FW(7Q10s) 33.8
ug/L
1 0 0.5 Acute: 391.2
no limit
Note: n<9 Default C.V. Chronic: 347.7
-----
Limited data set No value > Allowable Cw
Mercury
NC 12
FW(7Q10s)
0.5 ng/L
Acute: NO WQS
1 1 2.0
no limit
_ _ _ _ _ _
Note: n <_ 9 Default C.V. Chronic: 166.9
— — — --- —
Limited data set No value => Allowable Cw
Molybdenum
NC 160
WS(7Q10s)
ug/L
Acute: NO WQS
1 1 854.0
no limit
Note: n < 9 Default C.V. Chronic: 2,225.3
Limited data set No value > Allowable Cw
Page 1 of 2
9
4987-RPA - dewatering 1-2020, rpa
6/17/2020

Marshall Steam Station
2014 Freshwater RPA -
95% Probability/95% Confidence
Outfall 002 Dewatering 1
NC0004987
MAXIMUM DATA POINTS = 58
Qw = 3 MGD
Nickel
NC 25 WS(7Q10s) 261
ug/L 1 1 14.8
ll)cfaultC.
Acute: 3,020.8
no limit
Note: n 5 9 - .
Chronic: 347.7
---------
Limited data set
No value > Allowable Cw
Selenium
NC 5 FW(7Q10s) 56
ug/L 1 1 3.2
Acute: 648.1
no limit
Note: n<9 Default C.V.
Chronic: 69.5
---------
Limited data sei
No value > Allowablc C A
Zinc (AL)
NC 50 FW(7Q10s) 67
ug/L 1 1 50.0
Acute; 775.5
no limit
Note: n<9 Default C.V.
Chronic: 695.4
---------
Limited data set
No value > Allowable Cw
Page 2 of 2 4987-RPA - dewatering 1-2020, rpa
g 6/17/2020

REASONABLE POTENTIAL ANALYSIS
1
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
Arsenic - FW Standard
use -PASTE SPEGAL
Values" then -COPY"
2
Arsenic - HHMS Standards
. Maximum data
pomts = 58
Date Data BDL=112DL Results
Date Data BDL=112DL Results
3560 3560 Std Dev.
N/A
1
1/0/1900 0 3560 3560 Std Dev.
Mean
3560.0000
2
Mean
C.V.
0.0000
3
C.V.
n
1
4
n
5
Mult Factor =
1.00
6
Mult Factor =
Max. Value
3560.0 ug/L
7
Max. Value
Max. Pred Cw
3560.0 ug/L
8
Max. Pred Cw
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
Automatically copies
Arsenic data from FW
Standard entries
3560.0000
0.0000
1
1.00
3560.0 ug/L
3560.0 ug/L
-1-
4987-RPA - dewatering 1-2020, data
6/17/2020

REASONABLE POTENTIAL ANALYSIS
4
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
Cadmium
X
""-."'°" $Am
. Mie data:
d'.7
Date Data BDL=112DL Results
_
< 1 0.5 Std Dev.
N/A
Mean
0.5000
C.V.
0.0000
n
1
Mult Factor =
1.00
Max. Value
0.5 ug/L
Max. Pred Cw
0.5 ug/L
5
00.TA67Et;PR
Chlorides (AL)
tr1 .. .2 014X
Atmdftm dMPC
w
Date Data
BDL=1/2DL Results
1
288 288 Std Dev.
N/A
2
Mean
288.0
3
C.V.
0.0000
4
n
1
5
6
Mult Factor =
1.0
7
Max. Value
288.0
8
Max. Pred Cw
288.0
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
-2-
4987-RPA - dewatering 1-2020, data
6/17/2020

REASONABLE POTENTIAL ANALYSIS
$
Use "PASTE SPECIAL
9
Use "PASTE SF
Chromium
Values" then "COPY'
Copper (AL)
Values" then ",
Maximum data
Maxlmumt
points = 58
points - 6
Date Data BDL=1/2DL Results
Date Data BDL=1/2DL Results
1
< 1 0.5 Std Dev.
N/A
1
1.99 1.99 Std Dev.
N/A
2
Mean
0.5000
2
Mean
1.9900
3
C.V.
0.0000
3
C.V.
0.0000
4
n
1
4
n
1
5
5
6
Mult Factor =
1.00
6
Mult Factor =
1.00
mg/L
7
Max. Value
0.5 ug/L
7
Max. Value
2.0
mg/L
8
Max. Pred Cw
0.5 ug/L
8
Max. Pred Cw
2.0
9
9
10
10
11
11
12
12
13
13
14
14
15
15
16
16
17
17
18
18
19
19
20
20
21
21
22
22
23
23
24
24
25
25
26
26
27
27
28
28
29
29
30
30
31
31
32
32
33
33
34
34
35
35
36
36
37
37
38
38
39
39
40
40
41
41
42
42
43
43
44
44
45
45
46
46
47
47
48
48
49
49
50
50
51
51
52
52
53
53
54
54
55
55
56
56
57
57
58
58
4987-RPA - dewatering 1-2020, data
-3- 6/17/2020

REASONABLE POTENTIAL ANALYSIS
11
12
-
Uss'T%SrfE
" 46ie a
Fluoride
Yaiueil" tl�erl "CUPY"
Lead
.:. - _gip'"
-.
Maximum dfh
POW@ - 5B
pdjr�ls w7
Date Data BDL=1/2DL Results
Date Data BDL=1/2DL Results
_
1
2.78 2.78 Std Dev.
WA
1
< 1 0.5 Std Dev.
NIA
2
Mean
2.7800
2
Mean
0.5000
3
C.V.
0.0000
3
C.V.
0.0000
4
n
1
4
n
1
5
5
6
Mult Factor =
1.00
6
Mult Factor =
1.00
ug/L 7
Max. Value
2.8 ug/L
7
Max. Value
0.5
ug/L 8
Max. Pred Cw
2.8 ug/L
8
Max. Pred Cw
0.5
9
9
10
10
11
11
12
12
13
13
14
14
15
15
16
16
17
17
18
18
19
19
20
20
21
21
22
22
23
23
24
24
25
25
26
26
27
27
28
28
29
29
30
30
31
31
32
32
33
33
34
34
35
35
36
36
37
37
38
38
39
39
40
40
41
41
42
42
43
43
44
44
45
45
46
46
47
47
48
48
49
49
50
50
51
51
52
52
53
53
54
54
55
55
56
56
57
57
58
58
4987-RPA - dewatering 1-2020, data
-4- 6/17/2020

REASONABLE POTENTIAL ANALYSIS
IECIAL
;opy"
13
Mercury.
Use"PASTE SPECIAL
values" then "COPY"
14
Use"PASTE St
Molybdenum
Values' Men',
. Maximum c
fala
Maximum data
Palrth = 6
8
points = 58
Date Data BDL=112DL
Results
Date Data BDL=112DL Results
1
1.97 1.97
Std Dev.
N/A
1
854 854 Std Dev.
N±A
2
Mean
1.9700
2
Mean
854.0000
3
C.V.
0.0000
3
C.V.
0.0000
4
n
1
4
n
1
5
5
6
Mult Factor =
1.00
6
Mult Factor =
1.00
ug/L
7
Max. Value
2.0 ng/L
7
Max. Value
854.0
ug/L
8
Max. Pred Cw
2.0 ng/L
8
Max. Pred Cw
854.0
9
9
10
10
11
11
12
12
13
13
14
14
15
15
16
16
17
17
18
18
19
19
20
20
21
21
22
22
23
23
24
24
25
25
26
26
27
27
28
28
29
29
30
30
31
31
32
32
33
33
34
34
35
35
36
36
37
37
38
38
39
39
40
40
41
41
42
42
43
43
44
44
45
45
46
46
47
47
48
48
49
49
50
50
51
51
52
52
53
53
54
54
55
55
56
56
57
57
58
58
4987-RPA - dewatering 1-2020, data
-5- 6117/2020

REASONABLE POTENTIAL ANALYSIS
-.
15
16
Pu"
us&'PASTE SPECIAL
values" "COPY"
Nickel
then
Selenium
Maximum dau
points = 58
Date Data BDL=1/2DL Results
Date Data BDL=1/2DL Results
1
14.8 14.8 Std Dev.
N/A 1
3.15 3.15 Std Dev.
2
Mean
14.8000 2
Mean
3
C.V.
0.0000 3
C.V.
4
n
1 4
n
5
5
6
Mult Factor =
1.00 6
Mult Factor =
ug/L
7
Max. Value
14.8 ug/L 7
Max. Value
ug/L
8
Max. Pred Cw
14.8 ug/L 8
Max. Pred Cw
9
9
10
10
11
11
12
12
13
13
14
14
15
15
16
16
17
17
18
18
19
19
20
20
21
21
22
22
23
23
24
24
25
25
26
26
27
27
28
28
29
29
30
30
31
31
32
32
33
33
34
34
35
35
36
36
37
37
38
38
39
39
40
40
41
41
42
42
43
43
44
44
45
45
46
46
47
47
48
48
49
49
50
50
51
51
52
52
53
53
54
54
55
55
56
56
57
57
58
58
4987-RPA - dewatering 1-2020, data
-6- 6/17/2020

REASONABLE POTENTIAL ANALYSIS
Lise "PASTE SPEC 0
Values" then -COP,
. Maximum data
points = 59
M/A
3.1500
0.0000
1
1.00
3.2 ug/L
3.2 ug/L
18
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
ilea "PASTE 3PECl
Zinc (AL) Values" then "COF
. Maximum data
paints = 58
Date Data BDL=1/2DL Results .
50 50 Std Dev. N/A
Mean 50.0000
C.V. 0.0000
n 1
Mult Factor =
Max. Value
Max. Pred Cw
1.00
50.0 ug/L
50.0 ug/L
-7-
4987-RPA - dewatering 1-2020, data
6/17/2020

-Marshall Steam Station
NC0004987
Qw (MGD) = 3.00
1Q10S (cfs) = 49.15
7Q10S (cfs) = 60.00
7Q10W (cfs)= 60.00
30Q2 (cfs) = 60.00
Avg. Stream Flow, QA (cfs) = 60.00
Receiving Stream: Lake Norman
REASONABLE POTENTIAL ANALYSIS
2094 Generic RPA - 95% Probability/95% Confidence
MAXIMUM DATA POINTS = 58
WWTP/WTP Class:
IWC @ 1Q10S = 8.643123%
IWC @ 7Q lOS = 7.192575%
IWC @ 7Q10W = 7.192575%
IWC @ 30Q2 = 7.192575%
IWC @ QA = 7.192575%
Stream Class: WS-IV
Outfall 002 Dewatering 2
Qw=3 MGD
PARAMETER
TYPE
(1)
STANDARDS & CRITERIA (2)
�
W
1
REASONABLE POTENTIAL
RESULTS
RECOMMENDED ACTION
NC WQS / Applied '/z FAV /
Max Pred
Chronic Standard Acute
n # Det. Cw
Allowable Cw
Acute: NO WQSno
Sulfate
NC
250 WS(7Q10s)
mg/L
1 1 149.0
limit
Note: n 5 9 Default C.V.
Chronic: 3,475.81
Limited data set
No value > Allowable ('w
Acute: NO WQS
Aluminum
NC
87 FW(7Q10s)
µg/L
1 1
jDe7
no limit
-
Note: n < 9
_ _ _ _ _ _ _ _
Chronic: 1,209.58
Limited data set
No value > Allowable Cw
Acute: NO WQS
Barium
NC
1 WS(7Q10s)
mg/L
1 1 0.5
no limit_
Note: n 5 9 Default C.V.
___
Chronic: 13.90
_
Limited data set
No value > Allox aF,, I
Acute: NO WQS
Boron
NC
? WS(7Q10s)
mg/L
1 1 6.3
no limit
Note: n 5 9 Default C.V.
Chronic: 97.32
—
Limited data set
No value > Allowable Cw
Acute: NO WQS
Iron
NC
1 FW(7Q10s)
mg/L
1 1FDfa
no limit
Note: n < 9 C.V.
__ _ _ ___
Chronic: 13.90 —
Limited data set
No value > Allowable C=
Acute: NO WQS
Manganese
NC
200 WS(7Q 1 Os)
µg/L
1 1 1250.0
no limit
Note: n59 Default C.V.
_ _ _ _ _ _ _ _ _
Cbronic: 2,780.65
Limited data set
No value > Allowable CN,
Acute: NO WQS
Antimony
NC
5.6 WS(7Q10s)
µg/L
1 0 0.5
no limit
Note:n<9 Default C.V.
_ _
Chronic: —--77.86--
---------------------------
Limited data set
No value > Allowable Cw
Acute: NO WQS
Thallium
NC
0.24 WS(7Q10s)
µg/L
1 1 0.8
no limit
Note: n59 Default C.V.
_ _
Ch_ronic: ---- 3.34 --
---------------------------
Limited data set
No value > Allowable (
Acute: NO WQS
Vanadium
NC
24 FW(7QIOs)
µ
1 1 1.7
no limitglL
Note: n 59 Default C.V.
__ _ _____ _ _ _
Chronic: 333.68
_
Limited data set
No value :> Allowable Cw
Acute:
0 0 N/A
Chronic: — — --- —
— — — — — ----- — ----- — —
Page
1 of
2
4987-RPA dewaterring 2-2020, rpa
6117/2020

Marshall Steam Station
NC0004987
REASONABLE
2014 Generic RPA
POTENTIAL
- 95%
Probability195%
ANALYSIS
Confidence
Outfall 002 Dewatering 2
Qw = 3 MGD
Acute:
0 0
N/A
Chronic:----------
---------------------------
Acute:
0 0
N/A
__:
__
Chronic----------
---------------------------
Acute:
0 0
N/A
Chronic: — — — ---
— — — — ----- — ----- -----
Acute:
0 0
N/A
Chronic: --- — — —
--- — — — — — — — — --- ---
Acute:
0 0
N/A
Chronic:----------
---------------------------
Acute:
0 0
N/A
_ _ _
Chronic: --------------------------------------
Acute:
0 0
N/A
_ _ _ _
Chronic:----------
---------------------------
Acute:
0 0
N/A
Chronic:----------
---------------------------
Acute:
0 0
N/A
_ _ _
Chronic:----------
---------------------------
Acute:
0 0
N/A
_ _ _
Chronic:----------
---------------------------
Acute:
0 0
N/A
Chronic: --- — ---
— — — — — — — --- — — — ---
Acute:
I-T
0 0
N/A
Chronic:-------------------
----
Page 2 of 2 4987-RPA dewateMng 2-2020, rpa
9 6/17/2020

REASONABLE POTENTIAL ANALYSIS
Sulfate
Yait�ed'then "COPY"
Aluminum
�railus"OW-9
Maximum data
pubAm 4
points = SB
pa6rta+ i
Date Data BDL=1/2DL Results
Date Data BDL=1/2DL Results
_
1
149 149 Std Dev.
N/A
1
810 810 Std Dev.
N/A
2
Mean
149.0000
2
Mean
810.0000
3
C.V.
0.0000
3
C.V.
0.0000
4
n
1
4
n
1
5
5
6
Mult Factor =
1.0000
6
Mult Factor =
1.0000
7
Max. Value
149.0 mg/L
7
Max. Value
810.0
8
Max. Pred Cw
149.0 mg/L
8
Max. Pred Cw
810.0
9
9
10
10
11
11
12
12
13
13
14
14
15
15
16
16
17
17
18
18
19
19
20
20
21
21
22
22
23
23
24
24
25
25
26
26
27
27
28
28
29
29
30
30
31
31
32
32
33
33
34
34
35
35
36
36
37
37
38
38
39
39
40
40
41
41
42
42
43
43
44
44
45
45
46
46
47
47
48
48
49
49
50
50
51
51
52
52
53
53
54
54
55
55
56
56
57
57
58
58
4987-RPA dewaterring 2-2020, data
1 6/17/2020

REASONABLE POTENTIAL ANALYSIS
:opr
Sato
pg/L
pg/L
4987-RPA dewaterring 2-2020, data
- 2 - 6/17/2020

REASONABLE POTENTIAL ANALYSIS
Barium
Vdlu9a" then "COPY"
Boron
Vaiue!" then "�
Maximum data
Maxtmum i
points - 58
points - 5
Date Data BDL=1/2DL
Results
Date Data BDL=112DL Results
1
0.493 0.498
Std Dev.
N/A
1
6.27 6.27 Std Dev.
NIA
2
Mean
0,4980
2
Mean
6.2700
3
C.V.
0.0000
3
C.V.
0.0000
4
n
1
4
n
1
5
5
6
Mult Factor =
1.0000
6
Mult Factor =
1.0000
7
Max. Value
0.5 mg/L
7
Max. Value
6.3
8
Max. Pred Cw
0.5 mg/L
8
Max. Pred Cw
6.3
9
9
10
10
11
11
12
12
13
13
14
14
15
15
16
16
17
17
18
18
19
19
20
20
21
21
22
22
23
23
24
24
25
25
26
26
27
27
28
28
29
29
30
30
31
31
32
32
33
33
34
34
35
35
36
36
37
37
38
38
39
39
40
40
41
41
42
42
43
43
44
q4
45
45
46
46
47
47
48
48
49
49
50
50
51
51
52
52
53
53
54
54
55
55
56
56
57
57
58
58
4987-RPA dewaterring 2-2020, data
-3- 6/17/2020

REASONABLE POTENTIAL ANALYSIS
.°p,r
Iron
vemee' then -COPY"
Manganese
mu
. Maxlmmn data
a
points = ss
Date Data BD! =1/2DL Results
Date Data BDL=1/2DL
Results
1
8.55 8.55 Std Dev.
N/A
1
1250 1250
Std Dev.
2
Mean
8.5500
2
Mean
3
C.V.
0.0000
3
C.V.
4
n
1
4
n
5
5
6
Mult Factor =
1.0000
6
Mult Factor =
mg/L
7
Max. Value
8.6 mg/L
7
Max. Value
mg/L
8
Max. Pred Cw
8.6 mg/L
8
Max. Pred Cw
9
9
10
10
11
11
12
12
13
13
14
14
15
15
16
16
17
17
18
18
19
19
20
20
21
21
22
22
23
23
24
24
25
25
26
26
27
27
28
28
29
29
30
30
31
31
32
32
33
33
34
34
35
35
36
36
37
37
38
38
39
39
40
40
41
41
42
42
43
43
44
44
45
45
46
46
47
47
48
48
49
49
50
50
51
51
52
52
53
53
54
54
55
55
56
56
57
57
58
58
4987-RPA dewaterring 2-2020, data
4- 6/17/2020

REASONABLE POTENTIAL ANALYSIS
-j-p— "FrIV
Antimony
..tAeartnma �tr
pohttes:8&
_
Date Data BDL=112DL
Results
'A
1
< 1 0.5
Std Dev.
1250.0000
2
Mean
0.0000
3
C.V.
1
4
n
5
1.0000
6
Mult Factor =
1250.0 Ng/L
7
Max. Value
1250.0 Ng/L
8
Max. Pred Cw
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
valime eta
Thallium
Muimum data
pokfts_= 58
Date Data BDL=1/2DL
WA
1 0.828 0.828
0.5000
2
0.0000
3
1
4
5
1.0000
6
0.5 Ng/L
7
0.5 pg/L
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
-5-
4987-RPA dewaterring 2-2020, data
6/17/2020

REASONABLE POTENTIAL ANALYSIS
y"O'e lhe" -copy-
Vanadium
Madmum data
points a 50
Results
Date Data BDL=112DL Results
Std Dev.
N/A
1
1.73 1.73 Std Dev.
Mean
0.8280
2
Mean
C.V.
0.0000
3
C.V.
n
1
4
n
5
Mult Factor =
1.0000
6
Mult Factor =
Max. Value
0.8 ug/L
7
Max. Value
Max. Pred Cw
0.8 Ng/L
8
Max. Pred Cw
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
IIRaolkum.data
ppints a a
1.7300
0.0000
1
1.00
1.7 Ng/L
1.7 Ng/L
0
Date Data BDL=112DL
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
-6-
4987-RPA dewaterring 2-2020, data
6/17/2020

REASONABLE POTENTIAL ANALYSIS
VwaupR 1Mn-IaGF"►r
0
varufe" am"Co
N=bngm dam
dm
gym•-m
gnu- 5.9
Results
_
Date Data
BDL=112DL Results
Date Data
Std Dev.
NO DATA
1
Std Dev.
NO DATA
1
Mean
NO DATA
2
Mean
NO DATA
2
C.V.
NO DATA
3
C.V.
NO DATA
3
n
0
4
n
0
4
5
5
Mult Factor =
N/A
6
Mult Factor =
N/A
6
Max. Value
N/A
7
Max. Value
N/A
7
Max. Pred Cw
N/A
8
Max. Pred Cw
N/A
8
9
9
10
10
11
11
12
12
13
13
14
14
15
15
16
16
17
17
18
18
19
19
20
20
21
21
22
22
23
23
24
24
25
25
26
26
27
27
28
28
29
29
30
30
31
31
32
32
33
33
34
34
35
35
36
36
37
37
38
38
39
39
40
40
41
41
42
42
43
43
44
44
45
45
46
46
47
47
48
48
49
49
50
50
51
51
52
52
53
53
54
54
55
55
56
56
57
57
58
58
4987-RPA dewaterring 2-2020, data
-7- 6/17/2020

REASONABLE POTENTIAL ANALYSIS
0
v*1v "@m*CCF
. Ml�clnwrA'defs
pOtgts:atl�
BDL=1/2DL Results
Std Dev.
NO DATA
Mean
NO DATA
C.V.
NO DATA
n
0
Mult Factor =
N/A
Max. Value
N/A
Max. Pred Cw
N/A
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
Date Data
0
viduw am Wm
Maimum do
Pam a'as
BDL=112DL Results
Std Dev.
NO DATA
Mean
NO DATA
C.V.
NO DATA
n
0
Mult Factor =
N/A
Max. Value
N/A
Max. Pred Cw
N/A
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
Date Da
4987-RPA dewatemng 2-2020, data
-8- 6/17/2020

REASONABLE POTENTIAL ANALYSIS
U
vefpw "" ICOF
Fpt"%tas
to BDL=1/20L Results
Std Dev.
NO DATA
Mean
NO DATA
C.V.
NO DATA
in
0
Mult Factor =
N/A
Max. Value
N/A
Max. Pred Cw
N/A
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
Date Data
O
Values" then .'COF
. Maximum data
points = 58
BDL=1/2DL Results
Std Dev.
NO DATA
Mean
NO DATA
C.V.
NO DATA
n
0
Mult Factor =
NIA
Max. Value
N/A
Max. Pred Cw
N/A
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
Date
-9-
4987-RPA dewaterring 2-2020, data
6/17/2020

REASONABLE POTENTIAL ANALYSIS
0
VON"* msa s"
IltuNnuFn,�
pOhlht+�SE
Data BDL=1/2DL Results
Std Dev.
NO DATA
Mean
NO DATA
C.V.
NO DATA
n
0
Mult Factor =
N/A
Max. Value
N/A
Max. Pred Cw
N/A
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
Date Data
0
-- —, wr
MpdmUm *w
P�IRti=5lI-
BDL=1/2DL Results
Std Dev.
NO DATA
Mean
NO DATA
C.V.
NO DATA
n
0
Mult Factor =
N/A
Max. Value
N/A
Max. Pred Cw
N/A
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
-10-
4987-RPA dewaterring 2-2020, data
6/1712020

REASONABLE POTENTIAL ANALYSIS
4987-RPA dewaterring 2-2020, data
11 - 6/17/2020

REASONABLE POTENTIAL ANALYSIS
0
v*i�^
'
mot.
Date Data
BDL=1/2DL Results
1
Std Dev.
NO DATA
1
2
Mean
NO DATA
2
3
C.V.
NO DATA
3
4
n
0
4
5
5
6
Mu It Factor =
N/A
6
7
Max. Value
N/A
7
8
Max. Pred Cw
N/A
8
9
9
10
10
11
11
12
12
13
13
14
14
15
15
16
16
17
17
18
18
19
19
20
20
21
21
22
22
23
23
24
24
25
25
26
26
27
27
28
28
29
29
30
30
31
31
32
32
33
33
34
34
35
35
36
36
37
37
38
38
39
39
40
40
41
41
42
42
43
43
44
44
45
45
46
46
47
47
48
48
49
49
50
50
51
51
52
52
53
53
54
54
55
55
56
56
57
57
58
58
0
vahmwdm"l
.t,�
Date Data BDL=1/2DL Results
Std Dev.
NO DATA
Mean
NO DATA
C.V.
NO DATA
n
0
Mult Factor =
N/A
Max. Value
N/A
Max. Pred Cw
N/A
-12-
4987-RPA dewaterring 2-2020, data
6/17/2020

REASONABLE POTENTIAL ANALYSIS
Values" a' then
iota 0 Maximum data
I points = 58
Date Data
BDL=112DL Results
1
Std Dev.
NO DATA
2
Mean
NO DATA
3
C.V.
NO DATA
4
n
0
5
6
Mult Factor =
N/A
7
Max. Value
N/A
8
Max. Pred Cw
N/A
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
-13-
4987-RPA dewaterring 2-2020, data
6/17/2020

DEQ/DWR
FACT SHEET FOR NPDES PERMIT DEVELOPMENT/Major Modification
NPDES No. NC0004987
Facility
Information
Applicant/FacilityName:
Duke Energy —
Marshall Steam Station
Applicant Address:
Water Management, Duke Energy, P.O. Box 1006, Charlotte, NC
28201
Facility Address:
8320 E. NC Highway
150, Terrell, NC 28682
Permitted Flow
Not Limited
Type of Waste:
99.9% Industrial, 0.1% Domestic
Facili/Permit Status:
Major Modification
County:
Catawba
Miscellaneous
Receiving Stream:
Lake Norman
Regional Office:
Mooresville
Stream Classification:
WS-IV & B CA
USGS Topo
Quad:
Lake Norman North
303(d) Listed?:
No
Permit Writer:
Ser ei Chernikov, Ph.D.
Subbasin:
03-08-32
Date:
June 8, 2020
Drainage Area mil :
NA
4
Summer 7 10 cfs
Release 60 cfs
Winter 7Q10 cfs :
NA
1Q10 cfs):
IWC %):
23
SUMMARY
This permit is being modified to increase flow limit for Dewatering Phase from 1.0 MGD to 3.0 MGD
for Outfall 002.
Decanting of the ash basin is currently in progress. In the second half of 2020 the decanting phase of
the ash basin closure project will move into dewatering. The input from rainfall run-off and
dewatering activities will account for approximately 2 million gallons per day (MGD) to Outfall 002. A
pilot study for the groundwater remediation system associated with the Corrective Action Plan (CAP)
Update, submitted to NCDEQ on December 31, 2019, plans to begin in the first half of 2021 with the
full system being implemented shortly after. The full-scale remediation project will be extracting and
discharging an estimated 1 MGD of groundwater to Outfall 002. Infiltration wells are also included in
the remediation system, for which water will be pumped from Lake Norman, treated, then allowed to
infiltrate into groundwater to increase remediation system effectiveness. The infiltration wells will
increase aquifer productivity and flush out constituents from the unsaturated zone. Groundwater will
then be pumped from the aquifer through the extraction wells and sent to a Waste Water Treatment
System (WWTS) prior to discharging from Outfall 002. Therefore, the maximum daily discharge from
Outfall 002 is projected to be 3 MGD during the future ash basin closure activities.
A new WWTS is being built to treat wastewater generated from the dewatering activities. It will consist
of a high rate clarifier followed by filtration when needed. Ahead of the clarification, the wastewater
will be chemically treated to assist in metal precipitation and settleability. These chemicals may include,
organo-sulfide, hydrogen peroxide, sodium hydroxide, a coagulant and a polymer for a flocculent
Sodium Bisulfite may be used to ensure there is no excess of oxidant leaving the treatment system.
There will be a final pH adjustment step in which sulfuric acid or sodium hydroxide is used to ensure

the pH is within the limits. The sludge generated by the clarifier and filter backwash is planned to be
sent back into the ash basin for removal by the excavation contractor.
A new Reasonable Potential Analysis was conducted for Outfall 002 based on the 3.0 MGD flow
limit. The Analysis indicated that the Arsenic limits shall be reduced. Hence, the new Arsenic
limits have been incorporated into the permit.
All the remaining terms and conditions of the permit remain unchanged.
PROPOSED SCHEDULE
Draft Permit to Public Notice: June 30, 2020 (est.)
Permit Scheduled to Issue: August 31, 2020 (est.)
STATE CONTACT
If you have any questions on any of the above information or on the attached permit, please contact
Sergei Chernikov at [phone] or [e-mail].
NPDES Permit NC 0004987
Page 2

L� DUKE
rc ENERGY
June 8, 2020
Ms. Julie Grzyb
North Carolina Division of Water Resources
1617 Mail Service Center
Raleigh, NC 27699-1617
Subject: NPDES Wastewater Permit Modification Request
Duke Energy Carolinas, LLC.
Marshall Steam Electric Plant
NPDES Permit #: NC0004987
Catawba County
Dear Ms, Grzyb:
Marshall Stearn Station
8320 East NC Hwy 150
Terrell, NC 28682
828.478.7700
With reference to the April 29, 2020 permit modification request, additional information
is available for the planned installation of a new wastewater treatment system for Outfall
002. The narrative attachment of the modification request has been updated to reflect
this information. This update is attached,
If you have questions, please contact Robert Wylie at [phone] or
[e-mail].
Sincerely,
r
i
Rick Roper
General Manager III
Marshall Steam Station
cc: Wes Bell (electronic filing)
Attachment:
Update to April 29, 2020 Permit Modification Request

Attachment
Marshall Steam Station
Ash Basin Closure and Remediation Activities
Rage 1 of 2

Ash Basin Closure and Remediation Activities
Decanting of the ash basin is currently in progress. In the second half of 2020 the
decanting phase of the ash basin closure project will move into dewatering. The input from
rainfall run-off and dewatering activities will account for approximately 2 million gallons per
day (MGD) to Outfall 002. A pilot study for the groundwater remediation system associated
with the Corrective Action Plan (CAP) Update, submitted to NCDEQ on December 31, 2019,
plans to begin in the first half of 2021 with the full system being implemented shortly after.
The full-scale remediation project will be extracting and discharging an estimated 1 MGD of
groundwater to Outfall 002. Infiltration wells are also included in the remediation system, for
which water will be pumped from Lake Norman, treated, then allowed to infiltrate into
groundwater to increase remediation system effectiveness. The infiltration wells will
increase aquifer productivity and flush out constituents from the unsaturated zone.
Groundwater will then be pumped from the aquifer through the extraction wells and sent to a
Waste Water Treatment System (WWTS) prior to discharging from Outfall 002. Therefore,
the maximum daily discharge from Outfall 002 is projected be 3 MGD during the future
ash basin closure activities.
An evaluation of projected concentrations determined that only two metal parameters were
to be above the calculated allowable limits without treatment. These two parameters were
arsenic (from ash basin pore water) and mercury (from CAP wells). Therefore, a WWTS is
being implemented to remove these two parameters to concentration levels below the
calculated allowable limits.
This WWTS will consist of a high rate clarifier followed by filtration when needed. Ahead of
the clarification the water will be chemically treated to assist in metal precipitation and
settleability. These chemicals may include, organo-sulfide, hydrogen peroxide, sodium
hydroxide, a coagulant and a polymer for a flocculant. Sodium Bisulfite may be used to
ensure there is no excess of oxidant leaving the treatment system. There will be a final pH
adjustment step in which sulfuric acid or sodium hydroxide is used to ensure the pH is within
the limits. The sludge generated by the clarifier and filter backwash is planned to be sent
back into the ash basin for removal by the excavation contractor.
The ash basin closure project will also result in the need to build a larger landfill footprint.
The leachate from the larger footprint is planned to be sent to a retention basin which will
then pump the leachate to the wastewater Lined Retention Basin that discharge under the
NPDES permitted outfall 005. This outfall was permitted based on an estimated flow of 5
MGD. The actual flow has been historically less than 5 MGD. It is estimated that the flow
from the additional leachate flow will not change the previously projected long-term average
flow or loading of significance.
The flow schematic has been updated as follows to reflect the upcoming changes that are
requested with this permit modification request.
Page 2 of 2

Marshall Steam Station Water Schematic
10 Fan Control House NPDES Permit #NC0004987
> Non -contact Cooling Catawba Counter
Water internal - Permit Modification Request
0.2 MGD
Intake Screen April 2020
Backwash
— -- Outfall001
Once -through Cooling Water --- _ Lake
1093 MGD Norman
Ash Sluice Submerged Flight Conveyor Domestic Wastewater � Sanitary POTW
—
Evap. 1.7 MGD
Lake I _
Norman Flue Gas Desulfurization (FGD) Water Supply Groundwater Wastewater
Treatment Outfall002 Lake
Wet Scrubber Wastewater —_ from Lake Norman Extraction Wells 3.0 MGD Norman
System
FGD Wastewater Treatment System Internal Outfall GGG
L� —(Phys/Chem R 6io) 0.8 MGD
— -- —a Heat Exchanger Cooling Water 15 MGD -
- Storm Water
Air Preheater Water, Precipitator & Boiler Wash Waters, I
Misc. Cleaning Wastewaters
--- Fly Ash Silo Sump I�
Ash Basin
Dewatering
Misc. Equipment Cooling O.S3 MGD 0.04
MGD
Raw Water Stormwater —
Treatment c________ i
Boiler and Turbine _ ___ Yard Drain Sumps Outfalls O02Aand 002E
Room Sumps 1'9 (2 flows to IA) - Yard Sump Overflows --------
----------- Lake
_. MGD (no flow expected) Norman
Retention Basin Overflow
Coal Pile ------- — Alternate 2.43
---- - (no flow expected)
Route MGD
_ �/ -----------------------------
Stormwater HoldingBasin 0.5
MGD -- Retention Basin _ Outfall 00S Lake
5 MGD Norman
Landfill Leachate 0.04 MGD — -- J

w
-j� DUKE
`` ENERGY.
April 29, 2020
Ms. Julie Grzyb
North Carolina Division of Water Resources
1617 Mail Service Center
Raleigh, NC 27699-1617
Electronic Mailing
Subject: NPDES Wastewater Permit Modification Request
Duke Energy Carolinas, LLC.
Marshall Steam Station
NPDES Permit #: NC0004987
Catawba County
Dear Ms. Grzyb,
RECEIVED
MAY 1 M 2020
KDI_DoWNPHS
Marshall Stearn Station
8320 East NC My 150
Terrell, NC 28682
Duke Energy Carolinas, LLC (Duke) requests a modification to the NPDES permit
NC0004987 for Outfall 002 in order to support the closure and remediation activities
associated with the ash basin. It is projected that the 1 million gallons per day (MGD)
daily maximum flow restriction at Outfall 002 during dewatering of the ash basin will
need to be increased to 3 MGD. This increase in flow accounts for flows from
dewatering, rainfall run-off and extracted groundwater from remediation activities.
The details of upcoming closure and remediation activities that warrant the need to
increase flow restriction from 1 MGD to 3 MGD for Outfall 002 are attached. In the
future the Lined Retention Basin (LRB) (NPDES Outfall 005) will receive flows from a
larger landfill footprint, but this is not expected to result in a significant pollutant loading
to the LRB.
A check in the amount of $1,030 is being mailed separately to your office due changes
in processing associated with the coronavirus. If you have questions, please contact
Robert Wylie at [phone] or [e-mail].
SirMereiv, .
Rick Roper
General Manager III
Marshall Stearn Station
cc: Wes Bell (Electronic Mailing)
Attachment: Ash Basin Closure and Remediation Activities
828 478 7700

Attachment
Marshall Steam Station
Ash Basin Closure and Remediation Activities
Page 1 of 2

v
Ash Basin Closure and Remediation Activities
Decanting of the ash basin is currently in progress. In the second half of 2020 the
decanting phase of the ash basin closure project is anticipated to move into dewatering.
The input from rainfall run-off and dewatering activities will account for approximately 2
million gallons per day (MGD) to Outfall 002. A pilot study for the groundwater remediation
system associated with the Corrective Action Plan (CAP) Update, submitted to NCDEQ on
December 31, 2019, plans to begin in the first half of 2021 with the full system being
implemented shortly after. The full-scale remediation project will be extracting and
discharging an estimated 1 MGD of groundwater to Outfall 002. Infiltration wells are also
included in the remediation system, for which water will be pumped from Lake Norman,
treated, then allowed to infiltrate into groundwater to increase remediation system
effectiveness. The infiltration wells will increase aquifer productivity and flush out
constituents from the unsaturated zone. Groundwater will then be pumped from the aquifer
through the extraction wells and sent to a waste water treatment system (WWTS) prior to
discharging from Outfall 002. Therefore, the maximum daily discharge from outfall 002 is
projected to be 3 MGD during the future ash basin closure activities.
An evaluation of projected concentrations determined that only two metal parameters were
to be above the calculated allowable limits without treatment. These two parameters were
arsenic (from ash basin pore water) and mercury (from CAP wells). Therefore, a WWTS is
being implemented to remove these two parameters to concentration levels below the
calculated allowable limits.
The ash basin closure project will also result in the need to build a larger landfill footprint.
The leachate from the larger footprint is planned to be sent to a retention basin which will
then pump the leachate to the wastewater Lined Retention Basin that discharge under the
NPDES permitted outfall 005. This outfall was permitted based on an estimated flow of 5
MGD. The actual flow has been historically less than 5 MGD. It is estimated that the flow
from the additional leachate flow will not change the previously projected long-term average
flow or loading of significance.
The flow schematic has been updated as follows to reflect the upcoming changes that are
requested with this permit modification request.
Page 2 of 2

ID Fan Control House 1
Non -contact Cooling -
Water
} - _ :nternal Outfad or=
0.2 MGD
Intake Screen
Backwash
Marshall Steam Station Water Schematic
NP©ES Permit #NC0004987
Catawba County
Permit Modification Request
April 2020
Ii - > Once -through Cooling Water
Ash Sluice Submerged Flight Conveyor
Evap. 2.7 MGD
-
%ormar
Outfall 001
1093 MGD
Lake
Norman
Domestic Wastewater Sanitary POTW
Flue Gas Desulfurization (FGO) Water Supply " Groundwater
Wet Scrubber wastewater from Lake Norman
Extraction Wells
FGD Wastewater Treatment System
(Phys/Chem & Bio) Internal Outfall 006 i
-- - - — 0.8 MGD
Heat Exchanger Cooling Water 1.15 MGD
.. Air Preheater Water. Precipitator & Boiler Wash Waters,
Misc. Cleaning Wastewaters
Fly Ash Silo Sump
Misc. Equipment Cooling
O.S3 MGD 0.04
t JW Raw Water �`--`�
.
IV. GG
Treatment
Stormwater
Boiler and Turbine
Room Sumps t
1.9 vard Drain Su:nos -
--
MGD L (2 flows to l AI
Coal Pile
r__Alternate
2.43
Route
MGD
f
Stormwater 1Holding Basin 0.5
- MGD `>" Retention Basin
Landfill Leachate 0.04 MGD
Wastewater
Treatment Outfall002 _j Lake
System 3.0 MGD Norman
storm water
!
I
( Ash Basin
Dewatering
-------
Outfalfs 002A and 002E
-' Yard Sump Overflows --------t--------- Lake
(no flow expected)
Norman
Retention Basin Overflow
(no flow expected)
--------`-------------------
Outfall 005 Lake
5 MGD Norman

La Sala, Joseph Scott
From: Wylie, Robert R
Sent: Wednesday, April 29, 2020 1:00 PM
To: Grzyb, Julie; Chernikov, Sergei
Cc: Bell, Wes; Langley, Shannon; La Sala, Joseph Scott
Subject: RE: [External] MARSHALL NPDES PERMIT MODIFICATION NC0004987
Thanks Julie. The check is being sent from another area of the company so the hard copy will have to be sent in
separately.
From: Grzyb, Julie <[e-mail]>
Sent: Wednesday, April 29, 202012:56 PM
To: Wylie, Robert R <[e-mail]>; Chernikov, Sergei <[e-mail]>
Cc: Bell, Wes <[e-mail]>; Langley, Shannon <[e-mail]>; La Sala, Joseph Scott
<[e-mail]>
Subject: RE: [External] MARSHALL NPDES PERMIT MODIFICATION NC0004987
*** Exercise caution. This is an EXTERNAL email. DO NOT open
attachments or click links from unknown senders or unexpected
email. ***
Robert,
Thanks for the electronic copy. I am forwarding this modification request to Sergei via this email.
Please do send the hard copy with the check.
Thanks,
Julie
Julie A Grzyb
Supervisor
NPDES Complex Permitting
NC DEQ / Division of Water Resources / Water Quality Permitting
919 707 3605 office
336 210 8454 cell
iul� ie.arzyb@ncdenr_cLov
Physical Address: 512 North Salisbury St., Raleigh, NC, 27604
Mailing Address: 1617 Mail Service Center, Raleigh, NC, 27699-1617
Email correspondence to and from tivs address is subject to the
North Carolina Public Records Law and rrray be disclosed to third parties
From: Wylie, Robert R mailto:Robert.W lie duke-ener .com]
Sent: Wednesday, April 29, 202011:58 AM
To: Grzyb, Julie <juiie.erzyb ncdenr.gov>

Cc: Bell, Wes <wes.bell ncdenr. ov>; Langley, Shannon <Shann_on.Lanpley@duke-energy corn,>; La Sala, Joseph Scott
<Jose h.LaSala duke -ever .com>
Subject: [External] MARSHALL NPDES PERMIT MODIFICATION NC0004987
CAUTION: , al email Do not click links or open attachments unless you
Julie,
Attached is a NPDES permit modification request for Marshall Steam Station. This request was determined to be needed
after an evaluation was conducted for upcoming activities associated with the ash basin closure and groundwater
remediation. If you need a hard copy mailed to you please let me know. A check will be submitted separately, to your
office, for the cost to process this request.
If you have any questions or need additional information please let me know.
Thanks,
Robert Wylie
Duke Energy Corporation
Permitting and Compliance, Carolinas
704 382-4669 (office)
704 562-8258 (cell)
Robert.WylieCcDduke-energy.com