NC0024406_SOC WQ S18-009 amendment application_20190612

DUKE
ENERGY
June 12, 2019
Linda Culpepper, Director
NC Division of Water Resources
1617 Mail Service Center
Raleigh, NC 27699-1617
Paul Draovitch, P.E.
Senior Vice President
Environmental, Health & Safety
526 S. Church Street
Mail Code: ECUP
Charlotte, NC 28202
[phone]
Subject: SOC amendment application addendum
Belews Creek Steam station
NCO024406
EMC SOC WQ S 18-009
Dear Ms. Culpepper,
Enclosed please find an addendum to the application for amendment of the subject Consent
Order. This submittal contains additional detail as to constituents for which interim relief is
being sought.
If there are any questions about this matter please feel free to contact me or Shannon Langley at
[phone] or shannon.langley(aduke-energy.com.
Sincerel ,
-P
P 1 Dra witch, P.E.
SVP - Environmental, Health & Safety
Enclosure
cc: Jim Wells - via email
Richard Baker — via email
Matt Hanchey — via email
Joyce Dishmon/Filenet — via email
Brenda Johnson — via email
Reginald Anderson — Station Manager
www.duke-energy.com

Attachment
Addendum to Application for amendment to Special Order by
Consent
Belews Creek Steam station
Permit Number: NCO024406
Consent Order #: EMC SOC WQ S18-009
June 2019

SOC application Section II
SOC Compliance History
The facility has complied with all interim dates under the SOC.
Significant progress is being made towards relocation of the outfall from the Lined
Retention basin (LRB) away from the newly classified "unnamed tributary" (UT) to
the main stem of the Dan River.
Progress is being made in decanting the ash basin. As of May 26, 2018, the ash
basin has been decanted to an elevation 742.8' from a starting elevation of
748.0'.
Upon startup of the (LRB), the facility experienced two exceedences of the interim
discharge limit for selenium from outfall 003A. The facility quickly identified the
source of these exceedences and took immediate steps at significant costs to
address the conditions that led to those initial exceedences associated with
system startup.
The facility has measured values higher than the current Interim Action levels
(IAL) for total hardness, chlorides and total dissolved solids (TDS) in the UT. We
believe this to largely be a result of the way the LRB operates as a batch discharge
process with the source of these constituents being the FGD scrubber. Since its
startup, the LRB has discharged for approximately 5 hours each day.
The facility has complied with the interim discharge limits from outfall 003
however, small margin exists for selenium, sulfates and cadmium. Data received
just prior to the public notice of the Order indicated a slight increase in selenium
concentrations. Given the timing for SOC issuance, this data could not be
included in initial interim limit development.

SOC application Section IV
Why an SOC amendment is needed
An amendment to the SOC is needed to modify the UT Interim Action Level (IAL)
for total hardness, TDS, chlorides and sulfates. Duke also requests re-evaluation
of the interim limits for selenium at outfall 003 and 003A as well as cadmium and
sulfates at outfall 003 now that more data is available as to the operation of these
systems in their current state.
The SOC was issued with IAL's identical from a previous SOC for basin seepage
and without taking LRB hardness, chlorides, TDS or sulfates data into account as it
was anew system that had yet to come online. Additionally, flows from the LRB
— the system built to replace the ash basin — will have much lower flow rate than
the historic release from the ash basin but higher concentration of total water
hardness, TDS, chlorides and sulfates given that bottom ash sluice water has been
removed. The FGD wastewater system now comprises a higher percentage of the
total flow and consists of blowdown from a limestone slurry air emissions system
required for air quality permit compliance. There is no increase in mass or new
wastestream sources associated with recent system modifications but the
concentration is higher at the outfall under the current configuration since some
flows have been removed and the release process has been modified as
permitted.
It appears the cadmium permit limit for outfall 003 was developed without
considering the water hardness. Duke requests that this be re-evaluated in the
SOC and that a hardness dependent value be derived and used for hardness
dependent metals where these constituents are limited.