NC0004774_Comments_20180614

rfaN DUKEDuke Energy
ENERGY® Buck Combined Cycle
1385 Dukeville Roar]
Salisbury,NC 28146
June 14, 2018
Mr. Mike Templeton
Environmental Engineer
NC Division of Water Resources RECE%VE®!®Ei�RI®��
1617 Mail Service Center JUN 20 2.018
Raleigh, NC 27699-1617
Water ResOU1 on
Re: NPDES Wastewater Permit—Draft Permit Comments permitting
Duke Energy Carolinas, LLC.
Buck Combined Cycle and Buck Steam Station
Permit#: NC0004774
Rowan County
Dear Mr. Templeton,
Duke Energy Carolinas, LLC (Duke) submits the following comments on the draft National
Pollution Discharge Elimination System (NPDES) Permit for Buck Combined Cycle and Buck
Steam Station. This letter requests clarifications and /or modifications on specific provisions of
the draft permit.
Duke Energy appreciates NCDEQ's efforts to finalize the Permit, which addresses issues
associated with surface impoundment decommissioning and modifications required to facilitate
those changes. Should you have any questions or require additional information, please contact
Ms. Elizabeth Glenn at [phone] or at [e-mail].
"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,
4L,,,71.
Henry A. Botkins, Jr.
General Manager
Buck Combined Cycle

Duke Energy cc:
Shannon Langley via email
Dale Wooten
Max Gardner
Joanie Cooke
Richard Baker via email
Elizabeth Glenn/Filenet

Buck NPDES application update
NC0004774
Rowan County
Page 12
Measurement Frequency—Outfall 006 A.(4.)page 7
Duke Energy requests a demonstration of pH sampling over a period of 3 months. Daily pH
sampling will be conducted, per the NPDES wastewater permit, for 3 months to demonstrate
consistent ranges, thus reducing daily to weekly monitoring requirements. A potential Footnote
for pH sampling on outfall 006 at Buck:
After three months of daily sampling, the sampling frequency may be reduced to weekly if the
permittee demonstrates to the satisfaction of the Division's Mooresville Regional office that the
discharge pH does not vary widely.
"Daily/weekly" in the Table with reference to the footnote above.
Monitoring Requirements—Outfall 004 A.(6.) page 9
Outfall 004 is a new outfall to reflect the discharge of intake screen backwash. Intake screen
backwash is deemed permitted per 15A NCAC 02H .0106(f) and therefore does not require a
specific outfall and monitoring requirements. The existing permit for the Buck Steam station
allows intake screen backwash per special condition A(9) which states "Continued intake screen
backwash discharge is permitted without limitations or monitoring requirements". That
condition is identical to the intake screen backwash requirements in other Duke Energy permits
(and likely any other NC NPDES permit with the potential to discharge intake screen backwash).
Duke Energy requests that the proposed outfall 004 is removed and replaced with the current
language to be consistent with Division procedure and the NC regulations.
Buck will be undertaking monthly upstream and downstream sampling to evaluate impacts from
the station. This minor source will be captured in this effort.

Buck NPDES Draft Permit Comments
NC0004774
Rowan County
Page 13
Mislabeled Flows—Outfall 002 & 002A Fact Sheet,A.(1.)b.ii.,
A.(5.)a. & b.
No sanitary flows are discharged to connected systems that contribute to outfalls 002 and 002A.
All sanitary flows are handled by an approved septic system and an approved septage tank.
Please remove reference to sanitary flows for outfalls 002 and 002A.
Monitoring Requirements—Outfall 002A A.(5.) page 9
Duke Energy requests the sampling requirement of Fecal Coliform be removed from Outfall
002A. No sanitary flows are discharged to connected systems that contribute to outfall 002A.
All sanitary flows are handled by an approved septic system and an approved septage tank.
Monitoring Requirements—Outfall 002, OO1A & 006 A.(1.) p.!,A.(2.) p.3,
A.(3.) p.5,A.(4.)p.7
At Buck, the chemicals used within the cooling towers do not contain any of the 126 priority
pollutants, zinc or chromium. Therefore, it is requested that these parameters be removed from
the previously stated outfalls and replaced with the option to calculate the priority pollutants
from cooling tower maintenance chemicals.