NC0003468_Permit (Completion Request)_20220921

Permit NC0003468
STATE OF NORTH CAROLINA
DEPARTMENT OF ENVIRONMENTAL QUALITY
DIVISION OF WATER RESOURCES
PERMIT
TO DISCHARGE WASTEWATER UNDER THE
NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM
In compliance with the provision of North Carolina General Statute 143-215.1, other lawful
standards and regulations promulgated and adopted by the North Carolina Environmental
Management Commission, and the Federal Water Pollution Control Act, as amended,
Duke Energy Carolinas, LLC
is hereby authorized to discharge wastewater from a facility located at the
Dan River Combined Cycle Station
864 South Edgewood Road
Eden, NC
Rockingham County
to receiving waters designated as the Dan River in the Roanoke River Basin
in accordance with effluent limitations, monitoring requirements, and other applicable conditions set
forth in Parts I, II, and III hereof.
This major modification shall become effective November 1, 2022.
This major modification and authorization to discharge shall expire at midnight on October 31, 2027.
Signed this day September 23, 2022.
Richard E. Rogers, Jr., Director
Division of Water Resources
By Authority of the Environmental Management Commission
Page 1 of 9

Permit NC0003468
SUPPLEMENT TO PERMIT COVER SHEET
All previous NPDES Permits issued to this facility, whether for operation or discharge are hereby
revoked. As of this permit issuance, any previously issued permit bearing this number is no longer
effective. Therefore, the exclusive authority to operate and discharge from this facility arises under
the permit conditions, requirements, terms, and provisions included herein.
Duke Energy Carolinas, LLC
is hereby authorized to:
1. Continue to discharge the following:
• Outfall 001: cooling tower blowdown from the combined cycle unit, intake screen
backwash, and plant collection sumps (low volume wastes);
• Internal Outfall 001A (discharges to Outfall 001): wastes from the filtered water
plant including miscellaneous wash down water and laboratory wastes (low
volume wastes);
2. Discharge from said treatment works at the location specified on the attached map
into the Dan River (Outfall 001), classified C waters in the Roanoke River Basin.
Page 2 of 9

Permit NC0003468
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 intake screen backwash, cooling tower blowdown, and plant
collections sumps through Outfall 001. Such discharges shall be limited and monitored by the
permittee as specified below:
EFFLUENT
CHARACTERISTICS
LIMITS
MONITORING REQUIREMENTS
Monthly
Average
Daily
Maximum
Measurement
Frequency
Sample
Type
Sample
Location'
Flow, MGD
Daily
Pump Logs
Effluent
Temperature
37.2 °C
Weekly
Grab
Effluent
Temperature
32.0 °C 2
Weekly
Grab
Downstream
Total Suspended Solids
30.0 mg/L
100.0 mg/L
2/Month
Grab
Effluent
Oil and Grease
15.0 mg/L
20.0 mg/L
2/Month
Grab
Effluent
pH
6.0 <_ pH <_ 9.0
2/Month
Grab
Effluent
Total Residual Chlorine 3
28.0 pg/L
2/Month
Grab
Effluent
Notes:
1. Sample locations: Downstream - downstream approximately 85 ft.; Effluent - at point
downstream of combined wastewaters from the combined cycle turbine unit.
2. See Special Condition A. (6.) Temperature Mixing Zone.
3. Total Residual Chlorine (TRC) compliance is required only if chlorine or chlorine derivative is
added to the cooling water. The Division shall consider all effluent TRC values reported below
50 pg/L to be in compliance with the permit. However, the permittee shall continue to record
and submit all values reported by a North Carolina certified laboratory (including field
certified), even if these values fall below 50 pg/L.
The permittee shall obtain authorization from the Division of Water Resources prior to using any
biocide in the cooling water; see condition A. (5.).
There shall be no discharge of floating solids or foam visible in other than trace amounts.
Page 3 of 9

Permit NC0003468
A. (2.) EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS (Outfall
001A) [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 wastewater from the filtered water plant including wash down
water and laboratory wastes (low volume waste sources) through Internal Outfall OO1A. Such
discharges shall be limited and monitored2 by the permittee as specified below:
EFFLUENT
CHARACTERISTICS
LIMITS
MONITORING REQUIREMENTS
Monthly
Average
Daily
Average
Measurement
Frequency
Sample
Type
Sample
Locations
Total Suspended Solids
30.0 mg/L
100.0 mg/L
2/Month
Grab
Effluent
Oil & Grease
15.0 mg/L
20.0 mg/L
2/Month
Grab
Effluent
Notes:
1. Effluent sample location shall be at point downstream of the oil separator and prior to mixing
with Outfall 001.
Should no flow occur during a given month, the words "no flow" should be clearly written on the front
of the DMR. All samples shall be a representative discharge.
There shall be no discharge of floating solids or foam visible in other than trace amounts.
Page 4 of 9

Permit NC0003468
A. (3.) TOXICITY RE -OPENER CONDITION
[15A NCAC 02B .0200 et seq.]
This permit shall be modified, or revoked and reissued, to incorporate additional toxicity limitations
and monitoring requirements in the event that 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. (4.) SPECIAL CONDITIONS
[NCGS 143-215.3 (a) (2) and NCGS 143-215.66]
The following special conditions are applicable to all outfalls regulated by this permit:
a) There shall be no discharge of polychlorinated biphenyl compounds such as those once
commonly used for transformer fluid.
b) Nothing contained in this permit shall be construed as a waiver by the permittee of any right
to a hearing it may have pursuant to State or Federal laws or regulations.
c) Discharge of any waste resulting from the combustion of toxic or hazardous waste to any
waste stream which ultimately discharges to waters of the United States is prohibited, unless
specifically authorized in this permit.
d) The permittee shall report all visible discharges of floating materials (such as an oil slick) to
the Director when submitting DMRs.
e) "Upset," means an exceptional incident in which there is an unintentional and temporary
non-compliance with technology -based effluent limitations because of factors beyond the
reasonable control of the permittee. An upset does not include noncompliance to the extent
caused by operational error, improperly designed treatment facilities, inadequate treatment
facilities, lack of preventative maintenance, or improper operations.
f) All flows shall be reported on monthly DMRs. Should no flow occur during a given month,
the words "no flow" should be clearly written on the front of the DMR.
g) EPA methods 200.7 or 200.8 (or the most current versions) shall be used for analyses of all
metals except for total mercury.
h) All effluent samples for all external outfalls shall be taken at the most accessible location after
the final treatment but prior to discharge to waters of the U.S. (40 CFR 122.41(j)).
i) 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)).
j) The term chemical metal cleaning waste means any wastewater resulting from cleaning any
metal process equipment with chemical compounds, including, but not limited to, boiler tube
cleaning (40 CFR 423.11 (c)).
k) 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)).
1) 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.
m) The concentration of asbestos in any wastewater shall not exceed 7 million fibers per liter.
A. (5.) 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
Page 5 of 9

Permit NC0003468
receiving stream. Completion of Biocide Worksheet Form 101 is not necessary for those outfalls
containing toxicity testing. Division approval is not necessary for the introduction of new biocides into
outfalls currently tested for whole effluent toxicity.
A. (6.) TEMPERAURE MIXING ZONE
[NCGS 143-215.1]
a) The temperature mixing zone is defined as the area extending from outfall 001 to approximately
143 feet below the discharge. The discharge shall not result in acute toxicity to aquatic life, prevent
free passage of aquatic organisms around the mixing zone, result in offensive conditions, produce
undesirable aquatic life or result in a dominance of nuisance species outside of the assigned mixing
zone; or endanger the public health or welfare.
b) The temperature standard of 32°C (89.6°F) and the maximum temperature increase above natural
temperature of 2.8°C (5.04°F) shall be met at the end of the mixing zone. The natural water
temperature shall be the temperature measured at the upstream sampling location. The increase in
temperature is defined as the difference in temperature between the upstream and downstream
sampling locations.
c) The results of all temperature monitoring shall be reported in the monthly DMRs. When possible,
instream monitoring for temperature shall be performed during times the facility is operating at full
loading.
d) After 12 months of temperature data are collected the permittee shall submit a report to the
Division to verify the Cormix model predictions. The report shall include field verification of
assumptions used in the model and a summary of temperature data for effluent, upstream and
downstream and shall be submitted to:
Division of Water Resources
WQ Permitting Section - NPDES
1617 Mail Service Center
Raleigh, NC 27699-1617
f) This permit may be reopened to implement alternative temperature limits or requirements based
on the results of the data collected.
A. (7.) CLEAN WATER ACT SECTION 316(B)
[40 CFR 125.95]
Based on evaluation of the 316(b) study reports, the Department concludes that the existing
configuration at this facility represents BTA for meeting the impingement and entrainment
requirements of the Rule. The permittee shall continue to comply with the Cooling Water Intake
Structure Rule per 40 CFR 125.95.
Nothing in this permit authorizes take for the purposes of a facility's compliance with the Endangered
Species Act.
A. (8.) 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.
Page 6 of 9

Permit NC0003468
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
1. Reporting Requirements [Supersedes Section D. (2.) and Section E. (5.) (a)1
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 DENR / 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, 2025, 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.
Page 7 of 9

Permit NC0003468
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: http://www2.epa.gov/compliance/final-national-
pollutant-dis charge-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: / / deq.nc.gov/ about/ divisions /water -resources / edmr
4. Signatory Requirements [Supplements Section B. (11.) (b) and Supersedes Section B. (11.)
(dll
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: / / deq.nc.gov/ about/ divisions /water -resources / edmr
Certification. Any person submitting an electronic DMR using the state's eDMR system shall
make the following certification [40 CFR 122.22]. NO OTHER STATEMENTS OF CERTIFICATION
WILL BE ACCEPTED:
'7 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,
Page 8 of 9

Permit NC0003468
and complete. I am aware that there are significant penalties for submitting false information,
including the possibility of fines and imprisonment for knowing violations."
5. Records Retention [Supplements Section D. (6.)1
The permittee shall retain records of all Discharge Monitoring Reports, including eDMR
submissions. These records or copies shall be maintained for a period of at least 3 years from
the date of the report. This period may be extended by request of the Director at any time [40
CFR 122.41].
A. (9.) COMPLIANCE BOUNDARY
[15A NCAC 02L.0107]
The compliance boundary for the disposal system shall be specified in accordance with 15A NCAC
02L .0107(a) or (b) dependent upon the date permitted. An exceedance of groundwater standards at
or beyond the compliance boundary is subject to remediation action according to 15A NCAC 02L
.0106(c), (d), or (e) as well as enforcement actions in accordance with North Carolina General Statute
143-215.6A through 143-215.6C. The compliance boundary map for this facility is incorporated
herein and attached hereto as attachment.
Page 9 of 9