NC0004987_DRAFT Major Modification_20210209

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 9, 2021
Subject: Draft NPDES Major Modification
Permit NC0004987
Marshall Steam Station
Catawba County
Facility Class I
The Division has received your request for a Major Modification of the subject permit.
Enclosed with this letter is the modified permit. Please review this permit modification carefully to
ensure thorough understanding of the conditions and requirements it contains.
The draft permit modification contains the following significant changes from your current
permit:
• The bottom ash purge was added to the list of the contributing sources of wastewater to the
Lined Retention Basin (Outfall 005) . Per updated 40 CFR 423.13 (k) (2) (i) (A), the discharge
of pollutants in bottom ash transport water from a properly installed, operated, and
maintained bottom ash system is authorized to maintain system water chemistry where installed
equipment at the facility is unable to manage pH, corrosive substances, substances or
conditions causing scaling, or fine particulates to below levels which impact system operation
or maintenance.
• The Technology Based Effluent Limits for Total Arsenic, Total Mercury, Total Selenium, and
Nitrate/nitrite as N for Internal Outfall 006 (FGD wastewater) were adjusted in accordance
with updated 40 CFR 423.13.
• The pH limit for FGD wastewater was eliminated (Internal Outfall 006) to correct an error.
LD_E
NORTH CAROLINA
Department of Environmental Quay
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

Please provide any comments you have regarding the draft permit modification to this
office by March 15, 2021. At this time, the Division is also publishing a notice in the newspapers of
general circulation in Catawba County, inviting public comment on the Draft Modification. Following
the 30-day comment period, we will review all pertinent comments received and take appropriate action
on the permit modification.
If you have any questions about the NPDES permit process, please contact me at the
following e-mail address: sergei.chernikov@a,ncdenr.gov, or telephone number: 919-707-3606.
Sincerely,
Sergei Chernikov, Ph.D.
Environmental Engineer III
Industrial NPDES Permitting Unit
cc: Central Files
NPDES Files
EPA Region IV (e-copy)
Mooresville Regional Office/Water Quality (e-copy)
Mooresville Regional Office/PWS (e-copy)
WSS/Aquatic Toxicology Unit (e-copy)