NC0038377_Correspondence_20240327

ROY COOPER
Governor
ELIZABETH S. BISER
Secretary
RICHARD E. ROGERS, JR.
Director
NORTH CAROLINA
Environmental Quality
March 28, 2024
Ms. Jessica Bednarcik, Senior Vice President
Environmental, Health and Safety
Duke Energy Carolinas, LLC
Mail Code EC13K
P.O. Box 1006
Charlotte, North Carolina 28201-1006
Dear Ms. Bednarcik:
Subject: Final NPDES Permit
Permit NCO038377
Mayo Steam Electric
Generating Plant
Person County
Facility Class I
The Division of Water Resources is forwarding herewith the Final Permit for Mayo Steam Electric
Generating Plant. 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 the following significant changes from your Draft Permit:
• The Toxicity Test requirements were transferred from Outfall 002A to Outfall 002 to
maintain consistency among the power plant permits.
The Final Permit maintains the following significant changes contained in the Draft
Permit:
1. The description of Outfall 002 flows has been updated since all the process wastewater has
been rerouted to the Lined Retention Basin.
2. The Effluent Page for the decanting phase has been removed from the permit since the
facility moved to the dewatering phase in early October.
3. Internal Outfall 009 has been removed from the permit because all the FGD wastewater is
being evaporated by the VCE.
4. The sampling frequency for the instream monitoring has been reduced from Monthly to
Quarterly based on the review of the instream data.
5. The sampling frequency for the fish tissue monitoring has been reduced from annual to
once every five years based on the review of the fish tissue data.
6. The language for 316(b) condition has been updated to reflect the most recent decision to
recognize the existing intake structure as BTA for meeting impingement and entrainment
requirement of the CWA.
North Carolina Department of Environmental Quality I Division of Water Resources
NORTH CAROLINA
v 512 North Salisbury Street 11611 Mail Service Center I Raleigh, North Carolina 27699-1611
919.707.9000
Deportment of Emlmnmenbl 0.4l

7. The Water Quality Based Effluent Limits for Total Cadmium were added to the permit
(Outfall 002A — lined retention basin) based on the results of the RPA.
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,
Douglas Dowden
Environmental Supervisor II
Division of Water Resources
cc: Central Files
NPDES Files
Raleigh Regional Office/Water Quality
WSS/Aquatic Toxicology Unit (e-copy)
EPA Region IV (e-copy)
D E Q�� North Carolina Department of Environmental Quality I Division of Water Resources
512 North Salisbury Street 1 1611 Mail Service Center I Raleigh, North Carolina 27699-1611
NORrH CAROLINA 919.707.9000
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