NC0004961_Final_permit and Cover Ltr_20210215

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
February 15, 2021
Subject: Final NPDES Permit
Permit NC0004961
Riverbend Steam Station
Gaston County
Facility Class I
The Division of Water Resources is forwarding herewith the Final NPDES permit for Riverbend
Steam Station. This permit is issued pursuant to the requirements of North Carolina General Statute
143-215.1 and the Memorandum of Agreement between North Carolina and the U.S. Environmental
Protection Agency dated October 15, 2007 (or as subsequently amended).
The Final Permit contains no significant changes from your Draft Permit.
The Final Permit maintains the following significant changes contained in the Draft
Permit:
• The following Outfalls have been eliminated from the permit because the flow has ceased after
the ash ponds have been decommissioned and ash removed: 001, 002, 011, 101, 103, 104, 105,
106, 109, 110, 111, and 112.
• There are additional Outfalls that have been eliminated from the permit: 102, 107, and 108. The
seeps that have been assigned these Outfall numbers are still flowing, but following excavation
of the coal ash impoundment, they were found to be streams. If remediation of these streams
is necessary, it will be addressed through the corrective action plan for the former impoundment
or other administrative process.
• Outfall 002A has been repurposed for the discharge of the treated groundwater.
• Appendix A has been repurposed from Plan for Identification of New Discharges to the
Compliance Boundary Map to be consistent with other Duke permits.
• Chronic toxicity requirements have been transferred from Outfall 002 to Outfall 002A.
NORD
neaaromwnt ,t Environmental Qealit
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

• Groundwater Monitoring Well Construction and Sampling special condition has been removed
from the permit to be consistent with other Duke permits.
• Ash Closure Plan special condition has been removed from the permit due to the completion
of the coal ash excavation.
• Priority Pollutant Analysis condition has been removed from the permit since Outfall 002 is
closed.
• Chronic Toxicity Monitoring frequency was reduced from Monthly to Quarterly due to the
completion of the coal ash excavation.
• Ash Settling Basin special condition has been removed from the permit due to the completion
of the coal ash excavation and decommissioning of the coal ash basins.
• Total Copper and Total Iron Monitoring has been removed from the permit since the facility
has been decommissioned and no longer subject to 40 CFR 423.
• The type of sampling for Outfall 002A has been changed from Grab to Composite based on the
requirements of 15A NCAC 2B .0500.
• Monitoring for Arsenic, Selenium, and Mercury have been added to Outfall 002A based on the
permitting policy for coal-fired power plants.
• The Applicable State Law special condition has been removed from the permit due to the
removal of all coal ash from the site.
If any parts, measurement frequencies, or sampling requirements contained in this permit are
unacceptable to you, you have the right to an adjudicatory hearing upon written request within thirty
(30) days following receipt of this letter. This request must be in the form of a written petition,
conforming to Chapter 150B of the North Carolina General Statutes, and filed with the office of
Administrative Hearings, 6714 Mail Service Center, Raleigh, North Carolina 27699-6714. Unless such
a demand is made, this permit shall be final and binding.
Please note that this permit is not transferable except after notice to the Division. The Division may
require modification or revocation and reissuance of the permit. This permit does not affect the legal
requirements to obtain other permits which may be required by the Division of Water Resources or any
other Federal, State, or Local governmental regulations.
If you have any questions or need additional information, please contact Sergei Chernikov, telephone
number [phone] or email: [e-mail].
Sincerely,
DocuSigned by:
bvr
8FB19B649DD2478...
for S. Daniel Smith, Director
Division of Water Resources
cc: Central Files
NPDES Files
Mooresville Regional Office/Water Quality
WSS/Aquatic Toxicology Unit (e-copy)
EPA Region IV (e-copy)

Permit NC0004961
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
Riverbend Steam Station
Mount Holly
Gaston County
to receiving waters designated as the Catawba River (Mountain Island Lake) in the
Catawba River Basin
in accordance with effluent limitations, monitoring requirements, and other
applicable conditions set forth in Parts I, II, III, and Appendix A.
This permit shall become effective March 1, 2021.
This permit and authorization to discharge shall expire at midnight on
Signed this day February 16, 2021.
DocuSigned by:
�8FB 9 P6uf Witt
S. Daniel Smith, Director
Division of Water Resources
By Authority of the Environmental Management Commission
Page 1 of 8

Permit NC0004961
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:
• Remediation groundwater (Outfall 002A) .
From a facility located at Riverbend Steam Station, Mount Holly in Gaston
County, and
2. Discharge wastewater from said treatment works at the location specified on
the attached map into the Catawba River, which is classified WS-IV and B-CA
waters in the Catawba River Basin.
Page 2 of 8

Permit NC0004961
Part I
A. (1.) EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS (Outfall
002A) [15A NCAC 02B .0400 et seq., 02B .0500 et seq.]
During the period beginning on the effective date of this permit and lasting until expiration, the
Permittee is authorized to discharge from outfall 002A - Extracted Groundwater Discharge. 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 Location1
Flow, MGD
Weekly
Pump logs or estimate
Effluent
Total Suspended Solids
23.0 mg/L
75.0 mg/L
Monthly
Composite
Effluent
Oil and Grease
11.0 mg/L
15.0 mg/L
Monthly
Grab
Effluent
Total Selenium
Quarterly
Composite
Effluent
Total Arsenic
Quarterly
Composite
Effluent
Total Mercury2
Quarterly
Composite
Effluent
pH3
Monthly
Grab
Effluent
Chronic Toxicity4
Quarterly
Composite
Effluent
Notes:
1. Effluent samples shall be collected prior to the discharge to the receiving stream.
2. The facility shall use EPA method 1631E.
3. The pH shall not be less than 6.0 standard units nor greater than 9.0 standard units.
4. Whole Effluent Toxicity shall be monitored by chronic toxicity (Ceriodaphnia) P/F at 0.25%,
see Part A. (2.) for details.
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" SHOULD BE CLEARLY WRITEN ON THE FRONT OF
THE DMR. ALL SAMPLES SHALL BE OF A REPRESENTATIVE DISCHARGE.
Page 3 of 8

Permit NC0004961
A. (2.) CHRONIC TOXICITY PASS/FAIL PERMIT LIMIT (Outfall 002A) [15A NCAC
02B .0500 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 0.25%.
The permit holder shall perform at a minimum, quarterly 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). The tests will be performed during the months of
January, April, July, and October. These months signify the first month of each three-month
toxicity testing quarter assigned to the facility. Effluent sampling for this testing must be obtained
during representative effluent discharge and shall be performed at the NPDES permitted final
effluent discharge below all treatment processes.
If the test procedure performed as the first test of any single quarter 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 electronically using
the Division's eDMR system 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:
North Carolina Division of Water Resources
Water Sciences Section/Aquatic Toxicology Branch
1621 Mail Service Center
Raleigh, NC 27699-1621
Or, results can be sent to the email, ATForms.ATB@u,ncdenr.gov.
Completed Aquatic Toxicity Test Forms shall be filed with the Water Sciences Section no later than
30 days after the end of the reporting period for which the report is made.
Test data shall be complete, accurate, include all supporting chemical/physical measurements and
all concentration/response data, and be certified by laboratory supervisor and ORC or approved
designate signature. Total residual chlorine of the effluent toxicity sample must be measured and
reported if chlorine is employed for disinfection of the waste stream.
Should there be no discharge of flow from the facility during a month in which toxicity monitoring is
required, the permittee will complete the information located at the top of the aquatic toxicity (AT)
test form indicating the facility name, permit number, pipe number, county, and the month/year of
the report with the notation of "No Flow" in the comment area of the form. The report shall be
submitted to the Water Sciences Section at the address cited above.
Should the permittee fail to monitor during a month in which toxicity monitoring is required,
monitoring will be required during the following month. Assessment of toxicity compliance is based
on the toxicity testing quarter, which is the three-month time interval that begins on the first day of
the month in which toxicity testing is required by this permit and continues until the final day of the
third month.
Should any test data from this monitoring requirement or tests performed by the North Carolina
Division of Water Resources indicate potential impacts to the receiving stream, this permit may be
re -opened and modified to include alternate monitoring requirements or limits.
Page 4 of 8

Permit NC0004961
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. (3.) BIOCIDE CONDITION
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 a Biocide Worksheet 101 is not necessary for the introduction of a
new biocide into an outfall currently being tested for toxicity.
A. (4.) SPECIAL CONDITIONS
The following special conditions are applicable to all outfalls regulated by NC0004961:
• There shall be no discharge of polychlorinated biphenyl compounds.
• 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 the 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.
• The Permittee shall report all visible discharges of floating materials, such as an oil sheen, to the
Director when submitting DMRs
A. (5.) STRUCTURAL INTEGRITY INSPECTIONS OF ASH POND DAM
The facility shall meet the dam design and dam safety requirements per 15A NCAC 2K.
A. (6.) FISH TISSUE MONITORING
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 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 sampling is required upon commencement of the extracted groundwater discharge.
A. (7.) INSTREAM MONITORING
The facility shall conduct semiannual instream monitoring (one upstream and one downstream of the
remediation groundwater discharge) for arsenic, selenium, mercury (method 1631E), chromium, lead,
cadmium, copper, zinc, total hardness, and total dissolved solids (TDS). Instream monitoring should
be conducted at the stations that have already been established through the BIP monitoring program:
B (upstream of the Outfall 002) and C (downstream of the Outfall 002). The monitoring results shall
be submitted with the NPDES permit renewal application.
The sampling is required upon commencement of the extracted groundwater discharge.
Page 5 of 8

Permit NC0004961
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.
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. The eDMR system may be
accessed at: https://deq.nc.gov/about/divisions/water-resources/edmr.
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 following address:
NC DEQ / Division of Water Resources / Water Quality Permitting Section
ATTENTION: Central Files
1617 Mail Service Center
Raleigh, North Carolina 27699-1617
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; (This does not include the flow of waters over the dam
of 00F2 drainage waters from water treatment due to wet weather events causing 00F2
drainage flow rates to be above dry weather flows.)
• 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).
Page 6 of 8

Permit NC0004961
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:
https: / /www.federalregister.gov/ documents / 2015 / 10 / 22 / 2015-24954 / national-pollutant-
dis charge-elimination-system-npde s-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.)
ll
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
Page 7 of 8

Permit NC0004961
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."
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.) ADDITIONAL CONDITIONS AND DEFINITIONS
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.
2. All effluent samples for all external outfalls shall be taken at the most accessible location after
the final treatment but prior to discharge to waters of the U.S. (40 CFR 122.41(j)).
Page 8 of 8

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