NC0022454_LV-2019-0877 Response_20200122

(•� DUKE
ENERGY
January 17, 2020
Mr. Bob Sledge
North Carolina Department of Environmental Quality
1617 Mail Service Center
Raleigh NC 27699-1617
RE: Response to NOV-2019-LV-0877
Duke Energy Carolinas, LLC.
Belews Creek Steam Station
Special Order by Consent WQ S 18-009
Dear Mr. Sledge,
Paul Draovitch, P.E.
Senior Vice President
Environmental, Health & Safety
and Operations Support
526 S. Church Street
Mail Code: EC3XP
Charlotte, NC 28202
RECEIVED
JAN 2 2 2020
KDEUDWRODES
Duke Energy Carolinas, LLC (Duke Energy) appreciates the opportunity to provides this
response and supporting information to the subject Notice of Violation (NOV). Duke Energy
continues to progress with activities at the Belews Creek Steam Station in efforts to safely close
the Stations ash basin.
The noted exceedences in the NOV were the result of time critical events and deadlines driven
by required compliance with Consent Order EMC SOC S 18-004, the federal CCR rule and the
North Carolina Coal Ash Management Act. These circumstances were beyond the control of
Duke Energy and therefore covered under Section 4(d) of the subject Order. As such, Duke
Energy requests that the stipulated penalties noted in the NOV not be assessed or be assessed at a
level that accounts for the extenuating factors and the significant resources expended in efforts to
quickly abate the exceedences. This response is organized to address the exceedences in much
the same way they are listed in the subject NOV for ease of review by the Department staff.
Selenium exceedences at outfall 003A
Background
The Belews Creek NPDES permit was issued on March 21, 2019 and effective on March 25,
2019. Duke Energy had been planning and managing for months the activities associated with
the necessary switch over from the ash basin to the lined retention basin (LRB) in order to meet
the required decanting start date of March 31, 2019 established in Consent Order EMC SOC WQ
S 18-004 and to comply with the Federal CCR rule requirement to cease inputs to the ash basin
by April 11, 2019.
In order to be ready when the permit issued, Duke had to commission the LRB using flows
previously sent to the ash basin. However, only some of the historical flows were included, as
others (e.g. bottom ash sluice) had been eliminated by system modifications. As a result, while
no more mass of any particular pollutant was released from outfall 003A than historically from
outfall 003, the concentrations were elevated relative to historical flows. In support of this,
www.duke-energy.com

Mr. Bob Sledge
Response to NOV LV 2019-0877
January 17, 2020
Page 2 of 5
consider that the historic ash basin flows were a long-term average of 12.6 MGD while LRB
flows have been an average of approximately 2.4 MGD since their startup in March 2019. As a
result, the SOC selenium limit, which was based on historical flows and preliminary information,
was not well -tailored to actual operating conditions.
Two compliance samples were taken in the infancy of the newly commissioned wastewater
systems operation that were slightly over the relaxed limit. A sample on April 2, 2019 resulted
in a level of 85.4 ug/1(compared to a limit of 85.0 ug/1) and a sample on April 9, 2019 resulted in
a level of 89.5 ug/l (also compared to the limit of 85.0 ug/1).
Actions taken
Upon receiving the April 2 sampling result, the station took steps to remedy the concentrations of
selenium in the LRB. A cross -departmental team was organized. Through extensive daily
process sampling that commenced on April 4, 2019 and evaluation, the team was able to quickly
identify the major source of the selenium as being from the FGD Landfill Leachate. Speciation
of the selenium from the FGD landfill leachate revealed that the majority of the selenium was in
the form of selenate, a highly dissolved form that that is not removed in conventional wastewater
treatment systems.
The station stopped flows out of the FGD Landfill Leachate Basin on April 15, 2019 and
implemented temporary pumping and hauling measures until April 30, 2019 to initially dispose
of this water offsite by a third -party vendor. Soon thereafter, the station commenced internal
pump and haul operations of this wastewater to the FGD wastewater treatment system for
enhanced treatment, acting with appropriate DEQ Division approvals from DWR and DWM
staff. This initial effort amounted to pumping and hauling an approximate volume of 14,454,600
gallons of water at a cost of $1,317,407.
With adequate temporary handling measures in place, the team then performed an evaluation of
multiple potential permanent solutions in parallel. This effort began on May 3, 2019. This
process resulted in two major projects to eliminate water quality impacts from the operation of
the LRB.
1. Permanent re-routing of FGD landfill leachate to additional wastewater
treatment
After careful and thorough evaluation, the team chose to design and install a
permanent piping system to direct the FGD landfill leachate flows to the existing,
advanced wastewater treatment before release to the LRB and ultimately to the
permitted outfall. This significant amount of emergent work was completed in a
matter of months and consisted of 5,295 linear feet of new 6-inch 316L stainless steel
piping through the power plant to the wastewater treatment system. The new piping
is heat traced and insulated. This work resulted in costs of approximately $1,800,000
to implement and was placed into service on December 2, 2019.
2. Re-routing of flows from the LRB to the Dan River

Mr. Bob Sledge
Response to NOV LV 2019-0877
January 17, 2020
Page 3 of 5
The SOC required Duke Energy to relocate the flows from the LRB to the main stem
of the Dan River by on or before September 30, 2020. In response to the SOC
exceedences, Duke Energy expedited the re-route work and completed the re-route of
the LRB flows to the Dan River on July 13, 2019. This effectively eliminated the
discharge from the LRB to the newly designated unnamed tributary (UT) over a year
ahead of the required timeframe. Duke Energy advanced the project relative to earlier
forecasts by working at premium costs and by obtaining earlier -than -expected
cooperation from a third -party property owner. This re-route work costs $7,073,641.
Hardness, TDS and Chlorides IAL exceedences at downstream sampling location of the
Unnamed Tributary to the Dan River
Background
The SOC established interim action levels (IAL's) for a variety of constituents in the Unnamed
Tributary below outfall 111, 003 and 003A. On April 24 and May 21, 2019, sample results
exceeded the IAL values for water hardness. Water hardness is an aesthetic concern that can
cause scale to build up in pipes and water appurtenances. Elevated water hardness has no
adverse environmental effects on surface waters and may have a beneficial effect by decreasing
the bioavailability of certain metals, as reflected in the Department's hardness -dependent surface
water quality standards. The sample on May 21, also exceeded the IAL levels established for
TDS and chlorides.
Hardness, TDS and chlorides are constituents most commonly associated with FGD wastewater
and FGD landfill leachate at the station. These constituents are not treated by conventional
wastewater treatment methods and remain in water after treatment. These constituents were not
subject to limits in previous NPDES permits held by the station and even in previous DRAFT
permits prior to the issuance of the permit on March 21, 2019. The hardness, TDS and chlorides
levels detected were not the result of any improper operation or lack of due care on the part of
Duke Energy. There was no increase of long-term mass of these constituents with the
modifications and commissioning of the new wastewater treatment system; rather, as explained
above, the removal of certain other flows (e.g. bottom ash transport) resulted in higher
concentrations of these constituents in the resulting discharges from process operations.
Interim Action Levels designed to bridge the facility to a point where discharges were relocated
from the unnamed tributary were underestimates and not calibrated to actual operating
conditions. Seeing this after system startup, Duke Energy took the steps described below.
Actions taken
First, the relocation of the LRB discharge to the Dan River, described above, reduced the loading
of FGD-associated constituents to the Unnamed Tributary. The work undertaken to relocate the
discharge from the LRB from outfall 003A to outfall 006 was expedited. As described above,
this activity was completed over a year ahead of schedule and costs $7,073,641.

Mr. Bob Sledge
Response to NOV LV 2019-0877
January 17, 2020
Page 4 of 5
Second, upon clearer understanding of the characteristics of the UT during times where the LRB
was discharging (the LRB operates as a batch discharge and had not been operational prior to
permit and SOC issuance), a request for amendment of the SOC was developed. This was
submitted to the Department on April 16, 2019.
The discharge to the UT from the ash basin was also stopped on July 29, 2019. An expedited
project plan was put into place to redirect ash basin decanting flows, originally permitted to only
be released to the unnamed tributary, through outfall 003. On August 6, 2019, a permit
modification request to modify the sites NPDES permit and authorize decanting flows to be
directed to the Dan River via outfall 006A was submitted. This permit was issued on December
12, 2019. Decanting to the Dan River through outfall 006A commenced on January 6, 2019.
These actions assured that flows in the UT would remain compliant with the IAL's.
Minor permit limit exceedences for Sulfates
Background
A new sulfates limit in the permit became effective on March 25, 2019. Duke Energy requested
relaxation of the sulfates limit as part of its SOC request but was not granted any relief. Sulfates
pass through the treatment process. Increased sulfate concentration in the ash basin discharge can
largely be attributed to an increased proportion of the water being sent to the ash basin from
FGD treatment and landfill leachate after elimination of bottom ash transport waters on May 9,
2018. The removal of bottom ash wastewaters was required by Consent Order EMC SOC S 18-
004 and the North Carolina Coal Ash Management Act. As with other items discussed above,
this increased concentration did not mean more pollutant or any improper operation and
maintenance. Rather, it is a function of the steps Duke Energy had to undertake in preparation to
remove flows from the ash basin in accordance with other requirements found in the federal
CCR rule and the North Carolina Coal Ash Management Act and Consent Order S 18-004.
There is no stipulated penalty associated with the minor exceedences of sulfates, but that did not
result in any less aggressive a response to the noted exceedence. As discussed above, upon the
first exceedence of sulfates from the ash basin discharge, Duke Energy took the drastic step of
ceasing the discharge from the basin. Beyond that, Duke Energy expedited the re-route process
installing a new sump and pipeline to allow for ongoing decanting of the ash basin to be directed
to the Dan River.
After consulting with DEQ, Duke Energy determined that a permit modification was needed to
cover this activity, so decanting was paused for approximately 5 months while the DEQ drafted
and issued the NPDES permit modification.

Mr. Bob Sledge
Response to NOV LV 2019-0877
January 17, 2020
Page 5 of 5
The activities described above effectively completed the items required by the SOC (i.e. removal
of discharges via outfall 003 and 003A) well in advance of required timeframes. These actions
demonstrate Duke Energy's commitment to decisively addressing any items that were identified
at the startup of the new wastewater treatment system that were driven by timeframes beyond
Duke Energy's control.
Duke Energy believes that all of the exceedences noted in the subject NOV were driven by the
extenuating circumstances and timing of events that were out of Duke Energy's control. Duke
Energy asks the Department to consider the actions taken in response to these events, which were
under Duke's control, to see the level of commitment the company has to environmental
compliance.
If you have any questions regarding this letter, please contact Mr. Shannon Langley at (919) 546-
2439 or shannon.lan lgleey@duke-energ .com.
I certify, under penalty of law, that this document and all attachments were prepared under my
direction or supervision in accordance with a system designed to assure that qualified personnel
properly gather and evaluate the information submitted. Based on my inquiry of the person or
persons who manage the system, or those persons directly responsible for gathering the
information, the information submitted is, to the best of my knowledge and belief, true,
accurate, and complete. 1 am aware that there are significant penalties for submitting false
information, including the possibility of fines and imprisonment for knowing violations.
Senior Vice President
cc: WSRO DEQ WQ Supervisor w/enclosure
450 West Hanes Mille Road, Suite 300
Winston Salem, NC 27105
Joyce Dishmon - via email
Shannon Langley — via email
Chris Hallman — via email
Reggie Anderson — Belews Creek station manager
Brenda Johnson — via email