NC0024406_Updated Process Information_20180313

c - DUKE Belews Creek Steam Station
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ENERGY. Duke Energy Carolinas
3195 Pine Hall Road
Belews Creek,NC 27009
March 13,2018 RECEIVED/DENR/DWR
Mr.Sergei Chernikov,PhD
Division of Water Resources MAR 21 2018
1617 Mail Service Center
Raleigh,NC 27699-1617 Water Resource:
Permitting Sectro;
Subject: Updated Process Information
Belews Creek Steam Station-Permit No.NC0024406
Stokes County
Dear Dr.Chernikov:
Duke Energy Carolinas LLC, (Duke Energy) submits the following information in an effort to ensure the subject
renewed permit is accurate and based on the latest information. These application updates and comments are in
addition to previously submitted comments and permit application updates and discussions held in your office on
2/21/2018. The purpose of this letter is to provide additional clarity, planned activities have changed since the last
permit DRAFT was released. Duke Energy offers the following comments and requests for modification and/or
clarification on specific provisions of the Draft Permit:
1. Duke Energy intends to cease ash basin flows to the Dan River via outfall 003 with the closure of the ash
basin. As described in previous submittals,remaining wastewater flows currently directed to the ash basin
will instead be directed to a lined retention basin(LRB)for treatment. Operational flow from the LRB will
be discharged directly to the Dan River via a newly constructed outfall. Duke Energy requests the
addition of outfall 006 from the Lined Retention Basin which will discharge to the Dan River
approximately at coordinates 36°18'34.81"N:-80°04'36.10"W.
Duke Energy has constructed the pipeline that will temporarily send flows from the LRB to the Dan River
via outfall 003.Duke Energy plans to complete the construction of the LRB and the redirection of ongoing
contributing wastewater flow within the term of the proposed permit, thereby ceasing flows to outfall 003.
Therefore,Duke Energy asks that the Division include a compliance schedule for any new or revised limits
at outfall 003. During the compliance schedule,Duke proposes to submit yearly progress reports detailing
efforts to construct the basin, reroute internal flows, decant and close the ash basin, and construct the
discharge line to a new outfall 006 , with a final compliance milestone of having all wastewater flows
rerouted by the expiration date of the permit
2. The January 2017 draft permit proposes that the Belews Creek Steam Station develop a comprehensive
temperature analysis and Assessment of Balanced and Indigenous Populations,BIP. In anticipation of the
issuance of a final permit containing these requirements, Duke Energy conducted extensive temperature
monitoring in Belews Lake in 2017. The temperature monitoring included 12 locations that were
monitored monthly and 5 locations that were monitored hourly. The 5 hourly monitoring locations ranged
in depth from surface to a depth of 20 meters with temperature probes located at 2 meter intervals. This
robust data collection effort will form the basis of a study plan which will be submitted to NCDEQ for
review after issuance of the final NPDES permit. Duke Energy believes that the existing ongoing efforts in
support of the thermal variance combined with the NPDES required daily temperature monitoring at both
outfall 001 and at the Belews Lake dam are sufficient to characterize the plant's thermal discharge.
Therefore, Duke Energy requests the removal of the additional requirement for installation of
Downstream 1 temperature monitoring station from Condition A(1). If NCDEQ believes that

page 12
additional instream monitoring is required beyond what is currently required or proposed, then those
requirements should be vetted and recommended as part of the comprehensive thermal variance study plan
discussion.
NCDEQ has noted that the requirement to install an additional instream location is similar to what was
required in the 2015 Sutton NPDES permit. However,recall that the requirement at Sutton plan was put in
place in the absence of any prior temperature monitoring or study requirements in Sutton Lake. At the
Belews Creek Station,temperature characterization efforts are already well under way.
3. AOW S-11 is located downstream of the main dam and is the compliance sampling location for the
engineered seepage. Duke Energy requests that S-11 be relocated to the end of riprap channel
downstream of the main dam (approximately at coordinates 36°17'54.94"N:-80°04'32.57"W) with
this location considered a new outfall for all engineered seepage flows from the main dam in the
initial primary channel.
Decanting and closure of the basin will either eliminate or significantly reduce the flow from the new
outfall S-11. In the event that the flow is not eliminated by decanting or basin closure, Duke Energy will
re-route the flow to outfall 006 to the Dan River(Lined Retention Basin outfall). Duke Energy requests a
compliance schedule for any limits associated with this engineered seep and rerouting project. During the
compliance schedule,Duke proposes to submit yearly progress reports detailing efforts to dewater the basin
and potentially reroute seepage flows to 006, with a final compliance milestone of having all seepage
eliminated or rerouted within the term of the permit.
4. On page 3 of 31, Condition A(1) Footnote 2 Downstream 2 Temperature — The ambient temperature is
defined as the daily average downstream discharge water temperature. Duke Energy is requesting
clarification that the temperature monitoring is required only when there is discharge from the Lake Dam.
5. On page 22 of 31, Condition A(26) Instream Monitoring, instream monitoring locations requirement is
approximately 0.5 miles upstream and downstream of the ash pond discharge. These locations are
challenging due to safety concerns due to access location and shallow depth of river. Duke Energy
requests that the instream sampling locations be assigned as the Highway 311 bridge(approximately
2.7 miles upstream and the Pine Hall Road bridge (approximately 2.5 miles downstream) of
discharge of the ash pond basin. Relocation of instream sampling locations will not significantly impact
sample data.
Duke Energy requests consideration of all comments listed in Updated Process Information dated 12/5/2017. The
following are call outs for additional attention.
1. Comment#1 —Duke Energy requests removal of outfall 003A as an internal outfall. The Lined Retention
Basin process water reroute is designed to discharge to outfall 003 with the same compliance sample
location as the ash basin.
2. Comment#2—Duke Energy requests an internal outfall for the domestic wastewater lagoon and removal of
sampling requirement for fecal coliform and BOD from outfall 003.
3. Comment#3—Duke requests emergency spillways for the north and south coal pile basins. Location map
for the south coal emergency spillway at stormwater outfall SW018 A is attached — Attachment 1 —
Updated Site Map South Coal Basin Emergency Spillway.
4. Comment#8—An updated narrative description of sources of pollution and treatment technologies with the
updates highlighted was submitted with Updated Process Information letter.
5. Comment#10—Duke Energy requests removal of study of performance of the FGD wastewater treatment
system in condition A(31) based upon the remand of the ELG rule. In anticipation of the limits being
revised by EPA,Duke Energy,also requests the inclusion of a condition allowing the permit to be reopened

Page 13
and modified if the more stringent BAT limits for FGD wastewater and bottom ash transport water are
revised by EPA.
Duke Energy requests consideration of all comments listed in Comments on the DRAFT NPDES Permit letter dated
February 20,2017. The following are call outs for additional attention.
1. Comment#1 —Duke Energy requests modification of the May 1,2017 compliance date for the Dry Fly Ash
conversation identified on pages 6 and 8.
2. Comment#7—Duke Energy requests that the analysis for iron and copper be clarified to apply only during
"chemical"metal cleaning activities for outfall 003 and that the word "chemical"be added to Footnote#10
on pages 6 and 8.
3. Comment #8 — Duke Energy requests removal of monitoring requirements for TDS and Hardness be
removed from condition A(13) for outfall 005 based upon the contributing flow to this outfall is once
through cooling water and stormwater.
4. Comment #14 — Duke Energy requests clarity that the requirement for new EPA Form 2C data for this
outfall be changed from within 180 days from permit issuance to 180 days prior to the permit expiration
date. EPA 2C data were collected from outfall 001 on June 1, 2016 and submitted with renewal
application.
5. Comment#16—Duke Energy has never failed toxicity tests at the Belews Creek plant and monthly testing
during normal operations is not supported. Duke Energy requests that Toxicity testing remains a quarterly
requirement until ash basin dewatering commences.
Duke Energy welcomes any further discussion on our comments or the Draft Permit.If you have any questions,
please contact .yce Dishmon at 336-623-0238 or at [e-mail].
Sincerel
Reginald D.Anderson
General Manager III,Regulated Stations
Belews Creek Steam Station
Power Generating Carolinas East
Attachment
Cc: Ms.Karen Higgins—Belews Creek Public Hearing officer
1617 Mail Service Center
Raleigh,NC 27699-1617
Bc: Steven Conner,Mgr Environmental Services
Joyce Dishmon/Filenet,Sr.Env Specialist

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Attachment 1
Updated Site Map
South Coal Basin Emergency Spillway

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