NC0005088_Correspondence_20210618 (5)

U, DUKE
ENERGY.
January 8, 2021
Sergei Chernikov, PhD
North Carolina Department of Environmental Quality
Division of Water Resources
1617 Mail Service Center
Raleigh, NC 27699-1617
Subject: Rogers Energy Complex
NPDES Permit NC0005088
Amendment to pending NPDES permit modification request
Dear Dr. Chernikov:
Rogers Energy Complex
573 Duke Power Road
Mooresboro NC 28114
Duke Energy hereby submits an amendment to the January 15th, 2020 NPDES permit
modification request for the subject facility. Specific modification requests are
highlighted in bold throughout this submittal.
Duke Energy request that NPDES permit # NC0005088 be modified to incorporate
adopted steam electric Federal Effluent Guidelines found in 40 CFR Part 423.
Duke Energy requests that the amended concentration limits for FGD wastewater found
in the modified rule be incorporated into the permit. Those limits are as follows with
changes from the existing permit limits highlighted:
Pollutant
Existing monthly average/daily max
Modified ELG monthly
average/daily max
Arsenic
8 ug/I and 11/ug/I
8 ug/I and 18 ug/I
Mercury
356 ng/I and 788 ng/I
34 ng/I and 103 ng/I
Selenium
12 ug/I and 23 ug/I
19 ug/I and 70 ug/I
Nitrate/Nitrite
4.4 mg/I and 17 mg/I
3 mg/I and 4 mg/I
Duke Energy requests a 6-month extension of the FGD wastewater compliance
date to June 30, 2022. Duke Energy is actively constructing the wastewater treatment
system to treat flows from the FGD blowdown waste stream. Construction timeframes
have been expedited significantly to comply with the current NPDES permit compliance
date of December 31, 2021. The anticipated completion of construction is
approximately July 2021. This new system will consist of advanced physical/chemical
components along with biological treatment for removal of selenium. Based on our
operating and startup experience with these systems at other stations (e.g. Roxboro,
Marshall, Allen and Belews Creek), this short extension is needed to allow for adequate
time to properly start up the biological components and have them reach optimum
treatment performance levels. The biological components require significant time to

Dr. Sergei Chernikov
North Carolina Department of Environmental Quality
fivisinn of Water RP.soiimes
January 6, 2021
reach these treatment levels. Commissioning of the system at both Roxboro and
Marshall took approximately six months after the bioreactor was seeded, before the
system was functioning at optimum levels. This request is supported by the timeframe
estimates in our original requests for compliance schedule dated August 31, 2016 and
supports the Division's intent to expedite the original proposed compliance dates of
December 31, 2023 in an NPDES permit that was placed at public notice.
Duke Energy requests that the temperature monitoring upstream and
downstream of Outfall 005 be removed from the permit. Duke Energy has
submitted the report required by permit condition A. (27) to verify the CORMIX modeling
assumptions on which the 100°F daily maximum temperature limit was based. This
report was submitted on August 25, 2020. Given this, and the upstream and
downstream sampling data submitted to date (also analyzed in the report), the100°F
daily maximum effluent limitation is sufficient to assure that the instream 89.6°F
maximum and 5.04°F delta thermal standards are not exceeded outside the defined
mixing zone.
As discussed, and confirmed with NC DWR staff prior to submittal, this submittal is an
update to an existing permit modification request for which the appropriate fee was
previously submitted, therefore no check is included with this submittal.
If you have questions, please contact Robert Wylie at [phone] or
[e-mail].
Sincerely,
Jeff Joyce, General Manager II
Rogers Energy Complex
cc: Robert Wylie - via email
Steve Hodges
Shannon Langley — via email