NC0004979_Modification_20200207

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MICHAEL S.REGAN \ _
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Secretary
S.DANIEL SMITH NORTH CAROLNA
Director Environmental Quality
February 7,2020
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
Subject: Permit Major
Modification
Permit NC0004979
Allen Steam Station
Gaston County
Facility Class I
Dear Mr. Draovitch:
We have received your request for a Major Modification to extend compliance schedule for
FGD wastewater from 02/28/2020 to 11/01/2020 due to the latest EPA changes to 40 CFR 423.
The request has been granted.
Enclosed with this letter is 1 page that includes necessary changes. Please replace the existing
permit page with the modified page.
The permit modification contains the following significant changes from your
current permit:
• Extension of compliance schedule for FGD wastewater from 02/28/2020 to 11/01/2020
due to the latest EPA changes to 40 CFR 423.
No other changes have been made. This permit modification 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.
Please take notice that this permit is not transferable. Part II,E.4. addresses the requirements
to be followed in case of change in ownership or control of this discharge.
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If you have any questions or need additional information, please contact Sergei Chernikov,
telephone number [phone] or email: [e-mail].
Sincerely,
S. aniel Smi hector
ivision 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 NC0004979
A. (8.) EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS (Internal Outfall 005)
[15A NCAC 02B .0400 et seq.,02B .0500 et seq.]
During the period beginning on the effective date of this permit and lasting until permit expiration,the Permittee is
authorized to discharge from internal outfall 005-treated FGD wet scrubber wastewater to ash settling basin.
Such discharges shall be limited and monitored2 by the Permittee as specified below:
EFFLUENT LIMITS MONITORING REQUIREMENTS
CHARACTERISTICS
Monthly Daily Measurement Sample Sample
Average Maximum Frequency Type Location'
Pump logs or
Flow,MGD Monitor&Report Monthly similar Effluent
readings
Total Arsenic 8.0 µg/L4 11.0 µg/L4 Quarterly Grab Effluent
Total Mercury3,ng/L 356.0 ng/L4 788.0 ng/L4 Quarterly Grab Effluent
Total Selenium 12.0 µg/L4 23.0 µg/L4 Quarterly Grab Effluent
Nitrate/nitrite as N 4.4 mg/L4 17.0 mg/L4 Quarterly Grab Effluent
pH Monthly Grab Effluent
Footnotes:
1. "Effluent"shall be defined as the discharge from the FGD wastewater,treatment system prior to commingling
with other waste streams.
2. The permittee shall submit Discharge Monitoring Reports electronically using NC DWR's eDMR
application system. Please See Special Condition A. (26.).
3. The facility shall use method 1631E.
4. In accord with the Steam Electric Effluent Limitations Guidelines for FGD wastewater (40 C.F.R.
423), these limits shall become effective on November 1, 2020. This permit may be reopened and
modified if changes are made to 40 C.F.R. 423.
This permit shall be reopened and modified to reflect any changes in the 40 CFR 423.
All flows shall be reported on monthly DMRs. If no flow occurs during a given month,the words"no
flow"shall be clearly written on the front of the DMR. All samples shall be of a representative discharge.
The facility shall continue to operate the FGD treatment system until all coal-fired units are retired.
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