NC0038377_NOV-2024-LV-0863 Response Letter_20241108

DUKE Mayo Steam Plant
ENERGY: Duke Energy Progress
PROGRESS 10660 Boston Road
Roxboro NC 27574
November 5, 2024
Ms. Vanessa E. Manuel
Assistant Regional Supervisor
Water Quality Regional Operations Section
North Carolina Division of Environmental Quality
3800 Barrett Drive
Raleigh,NC 27609
Subject: Mayo Electric Generating Plant
NPDES Permit No.NCO038377
Notice of Violation& Intent to Access Civil Penalty
NOV-2024-LV-0863
Ms. Manuel:
The Mayo Steam Station, received your letter dated October 30, 2024, transmitting a Notice of Violation
and Intent to Assess Civil Penalty (NOV-2024-LV-0863) for North Carolina General Statute (G.S.) 143-
215.1 and the facilities NPDES permit. For the August 2024 Discharge Monitoring Report, Duke Energy
reported one daily maximum Fecal Coliform exceedance for Outfall 011. Fecal Coliform values at Outfall
011 are typically <_1 CFU/100ml. Duke Energy collected an additional three compliance samples during
the month of August. Outfall 011 returned to compliance the following week.
Date Result
8/06/24 510 CFU/100ml
8/14/24 <1 CFU./100 ml
8/19/24 59 CFU/100 ml
8/20/24 <1 CFU/100 ml
Duke Energy reviewed the system to determine the potential cause of the exceedance. There were no
changes or additional or increased flow to the system. Duke Energy contacted the Manufacturer of the
chlorine tablets used for disinfection and they confirmed the chlorine tablets were within the date for use.
For precaution,the chlorine tablets were replaced.
The attached Notification Letter dated 8/13/24 was sent to North Carolina Division of Water Resources,
North Carolina NPDES Industrial Permitting to update the current Permit Application file. Duke Energy
is in the final design of a new Domestic Wastewater Plant. The target date of startup of the new system is
2"d Quarter 2025.
Should you have any questions regarding this submittal or require additional information, please contact
Joyce Dishmon at 336-394-5524 or email Joyce.Dishmon`u�duke-energy.com.
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.
Sincerely,
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Jason Talbott
Plant Manager
Mayo Electric Generating Plant
Attachment
Cc: Leanne Wilson, Sr EHS Professional
Joyce Dishmon, Sr SME

Man o Stearn Mani
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6ME IOW)PosRm Road
ENERGY. Roxboro NC 27574
August 13, 2024
Dr. Sergei Chernikov
North Carolina Division of Water Quality
1617 Mail Service Center
Raleigh,NC 27699-1617
Subject: Duke Energy Progress, LLC.
Mayo Electric Generating Plant
NPDES Industrial Wastewater Permit NC0038377
Notification of Package Plant Replacement
Dear Dr. Chernikov:
Duke Energy Progress, LLC(Duke Energy) is submitting this letter as a notification that Duke Energy is
replacing the current Domestic Wastewater Treatment Package Plant with a like-in-kind system at Mayo
Electric Generating Plant. The target date of startup of the new system is 2°d Quarter 2025.
Duke Energy will adhere to the effluent conditions and monitoring requirements in permit Condition A(6)
- Internal Outfall 011 — Domestic Wastewater Plant and requests that submittal of this letter meet the
requirements for application File update and a permit modification not be required. If there are any questions
regarding this letter, please contact Joyce Dishmon via phone (336) 394-5524 or via email at
[e-mail].
1 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, trite, accurate, and complete. I am aware that there are significant penalties for
submitting false information, including the possibility of fines and imprisonment for
latowing violations.
Sin
Ja Talbott
General Manger—Mayo Steam Station
Cc: Vanessa Manuel,NCDEQ-RRO
Leanne Wilson, EHS
Joyce Dishmon, Permitting&Compliance