NC0003425_Supplemental Information_20160815

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Ss DUKE Hany IC Sideris
Senior Vice President
ENERGY® Environmental,Health&Safety
526 S.Church Street
Mail Code:EC3XP
Charlotte,NC 28202
REC E1 lED [phone]
NOV 071019
August 15, 2016 NCDEQIDWRINPDES
Ms. Teresa Rodriquez
North Carolina Division of Water Resources
1617 Mail Service Center
Raleigh,NC 27699-1617
Re: NPDES Wastewater Permit Application Submittal#8
Duke Energy Progress, LLC.
Roxboro Steam Electric Plant
Permit#: NC0003425
Person County
Dear Ms. Rodriquez,
Duke Energy Progress, LLC (Duke) is submitting herewith three copies of supplemental
information in support of the NPDES renewal application submitted in September 2011 for the
subject facility. This update is in addition to the previous updates and requests submitted dated
July 27, 2011, March 31, 2012, October 15, 2014, December 17, 2014, July 22, 2015 and July 5,
2016. Please include this supplemental information and the information in the previous
submittals in your review.
This submittal is intended to provide an update of modifications that will be necessary to comply
with recently enacted laws and regulations including the Federal Steam Electric Effluent
Guidelines (ELG), Federal Coal Combustion Residual(CCR)rule,the North Carolina Coal ash
Management Act of 2014 and HB 630 of 2016. Specific permit requests from Duke Energy are
identified in bold throughout this submittal.
With numerous federal and state requirements to coordinate and implement in a short time for
the site,planning and sequencing of work are paramount and dynamic. As such, final scope and
sequence for all work is not complete at this time. Where scope is still not finalized, Duke has
provided a range of options that are being evaluated and provided various alternate scenarios in
an attempt to limit the number of subsequent submittals necessary. As there are no requests for
previously unpermitted external outfalls to waters of the United States and all proposed
modifications contained herein are internal to our wastewater process flows, it is Duke's belief
that the information provided in this submittal is of sufficient detail to allow for review and
issuance or renewed NPDES permit for the Roxboro Steam plant. This is consistent with the
guidance received from DEQ staff in a meeting on November 20, 2015 and follow up
correspondence dated January 11, 2016 and January 28, 2016.

• Roxboro Steam Plant NPDES application update#8
NC0003425
Person County
Page 2 of 38
1. Duke requests a new internal outfall to be associated with a retention basin for
treatment of low volume waste. North Carolina's Coal Ash Management Act and the
Federal CCR rule will prohibit continued wastewater flows to the existing ash basin at
Roxboro. Projects are underway to convert ash handling of all ash(both bottom ash and
fly ash)to 100%dry handling and disposal systems. All other wastewater inputs to the
current ash basin must be redirected and handled in another manner. Duke intends to
construct a lined, retention basin to handle all flows currently directed to the active ash
basin with the following exceptions: Storm water runoff from the landfill on the east side
of Dunnaway road that currently flows to the ash basin will be relocated(discussed
below). Cooling Tower blowdown in cases where blowdown flows exceed 500 gpm will
be relocated(discussed below). Additionally, the retention basin will consist of two
basins: a primary and a secondary basin. The primary basin is where the majority of
solids settling will occur,while the secondary basin provides adequate retention time for
settling of fine particles. The primary basin will also have a location to allow various
vacuumed sediments and solids to be decanted prior to disposal of materials into the
onsite landfill. Periodically, any accumulated solids in the retention basin will be
disposed of in the facility's onsite landfill. The retention basin will be approximately II
acres in area and have the capability to have additional of flocculent and pH adjustment
chemicals. The primary basin will be designed for continuous flow through it.
A holding basin will be constructed for high volume flows such as air heater washes,
process washes, etc. The holding basin will have a chemical feed system for adjusting
pH and polymer addition to enhance settling. Once acceptable, the holding basin
contents will be transferred to the primary basin in the retention basin. The holding basin
will be designed for batch processing and will be approximately 6.6 Acres in area.
The requested internal outfall from the newly constructed retention basin will discharge
into the heated water mixing zone upstream of outfall 003 and ultimately flow to Hyco
reservoir thorough outfall 003 as is currently authorized by the subject permit. An aerial
photo with potential locations being evaluated for the new retention basin can be found in
Attachment 1.
Duke is evaluating the addition of a second retention basin southeast of the generation
units to be used to treat flows from silo wash water, stormwater runoff, landfill leachate
and runoff from the gypsum pad area. Flows from this basin would enter the heated
water effluent channel east of the generation units upstream of NPDES outfall 003.
Duke requests an internal outfall be added to the permit for this basin.

• Roxboro Steam Plant NPDES application update#8
NC0003425
Person County
Page 3 of 38
2. Duke requests that a new internal outfall for modified FGD wastewater treatment
system be added to the permit. To comply with Federal ELG guidelines for FGD
wastewater, a new treatment system for FGD wastewater will be constructed and utilized.
This system will consist of physical/chemical treatment units, a new Bioreactor and
ultrafiltration system. Solids settled and collected in the physical/chemical system will
be handled via a series of filter presses and disposed of in the facility's onsite landfill.
Duke intends to process legacy FGD wastewater through existing permitted outfall 010
until the treatment units associated with that outfall are decommissioned and closed. The
requested new internal outfall for FGD wastewater and outfall 010 will need to both be
operational for a period of time. The new internal outfall will be directed to the retention
basin described in item#1 of this letter. If the new FGD treatment system must be in
service before the retention basin is constructed, treated wastewater from the FGD
internal outfall will be directed to the heated water mixing zone upstream of NPDES
outfall 003 until the retention basin is completed. For reference,this is the point at which
current flows are released to Hyco Reservoir. The location of the new FGD wastewater
treatment system is identified in Attachment 1.
3. Duke intends to install heat exchangers or small auxiliary cooling tower for influent
flows to the new FGD wastewater treatment system. Duke requests that this flow be
listed as a contributing flow to outfall 003. Water will be withdrawn from within the
process heated water mixing zone, used to cool FGD blowdown prior to treatment in the
biological system and returned to the heated water mixing zone upstream of NPDES
outfall 003. The heat exchangers or small cooling tower will be utilized to assure process
water remains below bioreactor operational temperature requirements, which can
potentially present an operational concern during the summer months. This addition is
intended to assure efficient operation of the FGD blowdown treatment system.
4. Duke is installing a new domestic package plant for plant sanitary waste. Duke
intends to replace the current domestic package plant with a new above ground package
plant. The new domestic package plant will have a capacity of 0.025 MGD. With this
modification,Duke requests the flow limit of 0.015 MGD associated with the existing
plants design capacity be removed from outfall 008 or modified to 0.025 MGD to
reflect the new plant's capacity. Treated flows from the new plant will be directed to
the ash basin until such time that the retention basin described in item#1 is complete.
Upon completion of the retention basin, treated domestic flows will be sent to the
retention basin and flow to outfall 003 as they currently do. A narrative description and

• Roxboro Steam Plant NPDES application update#8
NC0003425
Person County
Page 4 of 38
specification sheet for the new domestic package plant is provided in Attachment 2 with
this submittal for your files.
5. Duke requests modification of the terms related to internal outfall 005(Unit#4
cooling tower blowdown). Currently, a slip stream of blowdown from the Unit 4
cooling tower is used to sluice ash and is directed to the ash basin. With modifications to
the plant to handle ash in a completely dry form and future prohibition on sending
wastewaters to the ash basin, Duke is requesting outfall 005 be permitted to be released
directly to the heated water mixing zone or to the retention basin described in item#1
above(based on Duke's future determination) as both of these flows paths are upstream
of NPDES outfall 003. Duke requests modification of NPDES permit condition A.
(14)to facilitate this change.
6. Duke intends to install a vapor suppression system in 2016 at the anhydrous
ammonia tanks to be used in the case of an emergency due to a release of anhydrous
ammonia. This modification is intended to enhance the safety of our employees and
local residents should there be an unintended release of anhydrous ammonia from the
facility's tanks. This system will use raw lake water from Hyco reservoir. The system
will be tested periodically with flows from tests (consisting of raw,untreated lake water)
entering the heated water mixing canal just to the west of the unit#4 cooling tower. In
the event of an actual emergency operation of the system due to a release of anhydrous
ammonia, flows from the vapor suppression system will follow this same flow path and
will potentially contain significant concentrations of ammonia. Upon completion of the
retention basin,test flows and emergency operation flows will be directed to the retention
basin described in item#1 of this letter. Flow rates for tests and emergency operation of
the vapor suppression system are anticipated to be approximately 1882 gallons per
minute. Duke requests concurrence in the permit that any impacts associated with
the emergency operation of this system do not constitute a violation of the permit.
Duke requests this flow be added to the list of flows tributary to outfall 003 and,
upon completion,the new retention basin described in item#1 of this submittal.
7. Landfill leachate is currently sent to the west ash basin. Landfill leachate flows will be
directed to one of the retention basins (both upstream of outfall 003) described in item #
1 upon completion of that basin. Duke requests that ELG permit limits associated
with landfill leachate be applied after the treatment provided in the retention basin
described in item#1 of this submittal.
1

• Roxboro Steam Plant NPDES application update#8
NC0003425
Person County
Page 5 of 38
8. Duke requests specific authorization within the reissued permit that upon ceasing
flows to the west ash basin, decanting and dewatering of the basin through existing
internal outfall 002 can occur. Specific authorization for decanting and dewatering is a
condition currently in the NPDES permit at Sutton and Marshall. Duke requests specific
authorization that the ash basin may be decanted and dewatered and what the permit
limits associated with that activity are. A characterization of the ash basin interstitial
water has been previously provided. This submittal was dated July 22, 2015. Decanting
and dewatering will occur through NPDES internal outfall 002 and will ultimately flow
to Hyco reservoir through NPDES outfall 003.
9. Duke requests the re-insertion of NPDES outfall 001 in the NPDES permit. This
outfall was removed from the NPDES outfall by the Department in 1994. There have
been no modifications to the flow since that time however, the flow originates at the
retired east ash basin remnant area and contains flow from several areas recently
identified as AOW's. Specifically, S-9, S-10, 5-11, S-12 and S-13 flow to the point of S-
13 which is the former outfall 001 in the NPDES permit. Chemical characterization of
this water was provided recently and was identified as S-13. If a full characterization of
the water is required, Duke request that this be made a condition of the permit and be
submitted 6 months after the permit effective date. Flows at this point consist of
stormwater through the remaining area of the retired east ash basin,the AOW's identified
above and other stormwater flows not associated with industrial activity.
10. Modifications associated with the coal pile runoff pond (NPDES outfall 006). Duke
is constructing an emergency gypsum stack out area on the west side of the plant near the
existing limestone ball mill and FGD filter press building. The emergency stack out area
is not expected to be used routinely and is being constructed to comply with Federal CCR
requirements. The area is approximately 0.3 acres in size. Runoff from the emergency
gypsum stack out and surrounding area including a lay down yard,truck wash facility
and gypsum conveyor system will flow to the coal pile runoff pond and to Hyco reservoir
after treatment through NPDES permitted outfall 006. Additionally,there is a need to
periodically drain a raw lake water tank located in the area of the coal pile runoff pond
for routine maintenance. As part of routine maintenance,this raw lake water tank may be
allowed to drain to the coal pile runoff pond. The tank can hold up to 50,000 gallons of
water.
11. Landfill storm water flows. As discussed above, storm water flows from the existing
landfill must be rerouted in order to comply with CAMA 2014 and the Federal CCR rule.
Landfill storm water flows consists of runoff from approximately 250 acres of landfill

• Roxboro Steam Plant NPDES application update#8
NC0003425
Person County
Page 6 of 38
and surrounding,up gradient area. Currently, storm water flows from the landfill flow
into the west ash basin for treatment prior to being released through NPDES outfall 003.
Currently three options are being considered for re-routing stormwater flows. An aerial
photo depicting these options is included with this submittal in Attachment 3
a. Option 1: Duke is evaluating the feasibility of constructing a stormwater
retention pond in the area just west of Dunnaway road between Dunnaway and
the active ash basin. Flow from this storm water retention pond would enter the
once through cooling water discharge canal and flow to Hyco Reservoir through
NPDES permitted outfall 003. Duke requests review and concurrence that this
modification is acceptable.
b. Option 2: Flows may be directed into the once through cooling water discharge
canal just to the north of the retired ash basin dam. The flow would then travel to
Hyco Reservoir through the heated water mixing zone and NPDES permitted
outfall 003 as it currently does. This will require permitting through NC DEQ
Dam Safety program. Duke requests review and concurrence that this
modification is acceptable.
c. Option 3: Duke is evaluating the feasibility of routing stormwater flows to the
plant's intake canal through the former NPDES outfall 001 discharge channel.
Outfall 001 was removed from the NPDES permit in 1994 due to the retirement of
the east ash basin. Duke has identified this discharge point into the intake canal
as a seep and the discharge location and sampling data is referenced as "S-13"in
previous submittals.
Duke believes that Option 1 and Option 2 above can be accomplished without permit
modification. Duke requests concurrence of this understanding. Duke believes that
if the flow identified as "S-13"in previous submittals is permitted as a seep to the intake
canal, or is reinserted into the permit as outfall 001, then Option 3 above can be
undertaken without additional permitting. If coverage for"S-13"is not necessary, it is
Duke understands that option 3 could be undertaken but may require industrial
stormwater coverage under NPDES General Permit NCG 12000. An aerial photo
showing the route and location for each of these options is included in Attachment 3.
Duke requests concurrence of this understanding.
12. Ongoing Landfill/Basin closure groundwater dewatering—Development of future
cells of the landfill and/or basin closure will require the lowering of groundwater levels in
and around the retired ash basin to meet separation and stability requirements for the
landfill. Duke intends to install a dewatering system and route extracted groundwater to

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Roxboro Steam Plant NPDES application update#8
NC0003425
Person County
Page 7 of 38
outfall 003 and/or the re-permitted outfall 001 after treatment. Duke requests this flow
be listed as a contributing flow to outfall 001 and outfall 003.
13. Steam Electric Effluent Guidelines Alternate schedule justification. Duke requests
an alternate applicability date for the Steam Electric Effluent Guidelines in
accordance with the request found in Attachment 4.
As the Steam Electric Effluent Guidelines makes clear, BAT limits may apply-depending
on the individual circumstances of the facilities subject to the rule- any time within the
window of November 1, 2018 to December 31, 2023. In selecting an appropriate
applicability date for each waste stream subject to the new BAT limits,the permitting
authority is called upon to determine an "as soon as possible" date when supplied with
appropriate information by the permittee. Attachment 4 provides the appropriate information
justifying the following applicability dates:
— Bottom Ash Transport Water: To convert the wet bottom ash transport system at
Roxboro to a closed loop system, Duke plans to install a remote mechanical drag
chain system(RMDS). Duke would like to request April 30, 2021 as the
applicability date for the zero discharge of bottom ash transport water, assuming a
permit effective date of October 1, 2016.
- FGD wastewater: Duke is planning on conducting several evaluations to
determine whether the FGD wastewater flow can be reduced, and the existing
bioreactor can be utilized in addition to evaluating viable selenium reduction
technologies. These evaluations will allow Duke to select the most cost effective
FGD wastewater system for Roxboro. In addition, it has recently come to Duke's
attention GE is claiming intellectual property rights on the biological treatment
system for FGD wastewater, thus, making GE the sole provider of EPA's model
technology. With these evaluations in process and the uncertainty of GE's
intellectual property claim, Duke would like to request December 31, 2023 as the
applicability date for the BAT limits for FGD wastewater, assuming a permit
effective date of October 1,2016.
— Fly Ash Transport Water: Fly ash is handled dry during normal operation;
therefore, Duke is not requesting an applicability date for the zero discharge of fly
ash transport water beyond November 1, 2018.
14. CWA Section 316(b) alternate schedule. Duke requests an alternate schedule for
compliance with Section 316(b)of the Clean Water Act. Specifics of the request can
be found in Attachment 5.

• Roxboro Steam Plant NPDES application update#8
NC0003425
Person County
Page 8 of 38
15.Area of wetness (AOW) disposition.
Duke has previously identified a number of Areas of Wetness within the property.
All of these AOW's are upstream of permitted outfalls. Consequently,Duke
requests that there be no sampling required for the AOW's. These de minimus AOW
flows are part of existing processes and are sampled through NPDES outfalls. Duke
requests that the AOW's be listed as contributing flows the respective outfall in
either the NPDES permit of NPDES permit fact sheet as follows: AOW's that are
contributing flows to NPDES outfall 003 are: S 1, S2, S3, S4, S5, S6, S7, S8, S14, S18
and S 19. AOW's that are contributing flows to requested NPDES outfall 001 are: S9,
S 10, S 11, S12 and S13. Duke requests that any future AOW's that are identified and
are tributary to these permitted outfalls not require notification to DEQ.
16. Duke has included an updated water process flow chart with this submittal that
shows the water flow path for the site after the ash basin is no longer used. This can
be found in Attachment 6. The only substantive change in flow volumes will be the
removal of ash sluice flows. This volume is negligible at outfall 003.
We appreciate your attention to these requests and look forward to finalizing the NPDES permit
for the Roxboro Steam Electric plant in the near future. Should you have any questions
regarding this letter or require additional information, please contact Mr. Shannon Langley at
[phone] or at [e-mail].
"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. I am aware that there are significant penalties for submitting false information,
including the possibility of fines and imprisonment for knowing violations."
Sincerely,
Harry Sideris
SVP-Environmental,Health&Safety
Enclosures

Roxboro Steam Plant NPDES application update#8
NC0003425
Person County
Page 9 of 38
NCDEQ cc: Sergei Chernikov
Duke Energy cc: William J.Thacker, Shannon Langley,Robert Howard,Rob Miller,Danny Satterwhite

Attachment 1
Proposed retention basin location
August 15, 2016 NPDES application update
Roxboro Steam Plant
NC0003425

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Attachment 2
Domestic package plant narrative description and
specification sheet
August 15, 2016 NPDES application update
Roxboro Steam Plant
NC0003425

Roxboro Steam Electric Plant Domestic package
plant improvements
Sanitary wastewater at Roxboro station is currently treated in an in ground package wastewater
treatment system which is more than 20 years old. A new package plant is being installed to
replace the existing package plant on an in-kind basis.
The new package plant will be installed above grade on a concrete foundation. The plant will
have an average capacity of 15,000 gallons per day with a peak capacity of 25,000 gallons per
day. The process will consist of an influent comminutor, influent equalization, extended
aeration, secondary clarification, disinfection, and effluent pumping.
Wastewater will be pumped from the equalization tank to the aeration tank through a flow
control weir box,which will maintain a constant forward flow rate as long as there is wastewater
in the equalization tank. The package plant will arrive with course bubble aeration diffusers
pre-installed. Air to the process will be supplied by a connection to the plant air
system. Aeration piping will include a filter and pressure reducing valves to condition the air
supplied to two zones: zone 1 includes the equalization tank and the waste sludge tank, and zone
2 includes the aeration tank itself Mixed liquor from the extended aeration process will flow by
gravity to the secondary clarifier.
Biomass settled in the clarifier will be pumped via air lift pump back to the aeration tank as RAS
or to the waste sludge tank as WAS, where sludge will be accumulated prior to disposal off-
site. Clarified effluent will leave the clarifier by a series of v-notch weirs and flow to the
chlorination chamber for disinfection. A two-tube tablet chlorinator will be installed in the
chlorination chamber to provide chlorine for disinfection.
Treated effluent will be pumped to the Unit 3-4 sump via the existing effluent pipeline for the
existing package plant. Flows from the Unit 3-4 sump are currently directed to the ash basin.
Upon completion of the retention basin, flows from the package plant will be redirected to the
retention basin and ultimately to Hyco Reservoir through NPDES outfall 003. The package plant
will be insulated to help prevent freezing.

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Attachment 3
Landfill Stormwater flow options aerial photo
August 15, 2016 NPDES application update
Roxboro Steam Plant
NC0003425

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Attachment 4
Steam Electric Effluent Guidelines Alternate
Schedule justification
August 15, 2016 NPDES application update
Roxboro Steam Plant
NC0003425

Roxboro Electric Generating Plant: Effluent Guidelines Rule
Justification for Applicability Dates
A. Introduction
Duke Energy (Duke) is workingdiligently to developand refine an optimized schedule for the
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installation and upgrades to wastewater treatment systems to comply with the Steam Electric Power
Generating Effluent Limitation Guidelines(ELG)at seven coal-fired stations in North Carolina. Duke
submits the following information as a justification for appropriate applicability dates for compliance
with the new Effluent Guidelines Rule (ELG Rule) (80 Fed. Reg. 67,838 (Nov. 3, 2015)) at Roxboro
Electric Generating Plant(Roxboro),located near Roxboro,North Carolina.
Roxboro consists of four coal fired generating units with nameplate generating capacities of 410.8,
657, 745.2, and 745.2 MWe for Units 1, 2, 3, and 4 respectively. The station currently discharges
treated bottom ash transport water, and FGD wastewater. Under normal plant operations, fly ash is
collected dry and either disposed in a permitted on-site landfill or transported offsite for beneficial
reuse. If the dry fly ash collection system is not operating, the fly ash is sluiced to the ash basin in
which the transport water is treated in the ash basin and subsequently discharged through outfall 002.
Bottom ash from the boilers is sluiced with transport water to the west ash pond. The transport water
is treated by the ash pond system and is discharged through outfall 002. The FGD blowdown is
discharges to a gypsum settling pond were suspend solids are settled out prior to flowing to the
bioreactor. The bioreactor effluent is discharged to the effluent channel through outfall 010 prior to
outfall 002.
The ELG Rule sets a range of possible applicability dates for compliance with the new BAT limits for
bottom ash transport water (zero discharge) and FGD wastewater (numeric limits for selenium,
arsenic, mercury, and nitrate/nitrite), as well for fly ash transport water (zero discharge). The
regulation provides that all permits issued after the effective date of the rule (January 4, 2016) should
contain applicability dates for compliance with the BAT limits, and that those dates should be "as
soon as possible"but not sooner than November 1,2018 and not later than December 31,2023.
For Roxboro, since the plant's final NPDES permit will be issued after January 4, 2016, but before
November 1, 2018, EPA specifically instructs permit writers to "apply limitations based on the
previously promulgated BPT limitations or the plant's other applicable permit limitations until at
least November 1, 2018." 80 Fed. Reg. at 67,883, col. 1 (emphasis added). As the rule makes clear,
however, BAT limits may apply—depending on the individual circumstances of the facilities subject
to the rule—any time within the window of November 1,2018 to December 31,2023. In selecting an
appropriate applicability date for each waste stream subject to the new BAT limits, the permitting
authority is called upon to determine an"as soon as possible"date.

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The ELG Rule provides a very specific definition for"as soon as possible." The permit writer—when
supplied with appropriate information by the permittee—must consider a range of factors that affect
the timing of compliance. Those factors are as follows:
(1)Time to expeditiously plan(including to raise capital),design,procure,and install
equipment to comply with the requirements of this part.
(2)Changes being made or planned at the plant in response to:
(i)New source performance standards for greenhouse gases from new fossil fuel-
fired electric generating units,under sections 111, 301,302,and 307(d)(1)(C)of the
Clean Air Act,as amended,42 U.S.C. 7411, 7601,7602,7607(d)(1)(C);
(ii)Emission guidelines for greenhouse gases from existing fossil fuel-fired electric
generating units,under sections 111,301,302,and 307(d)of the Clean Air Act, as
amended,42 U.S.C. 7411,7601,7602,7607(d); or
(iii)Regulations that address the disposal of coal combustion residuals as solid waste,
under sections 1006(b), 1008(a),2002(a), 3001,4004,and 4005(a)of the Solid Waste
Disposal Act of 1970,as amended by the Resource Conservation and Recovery Act
of 1976,as amended by the Hazardous and Solid Waste Amendments of 1984,42
U.S.C. 6906(b),6907(a),6912(a),6944,and 6945(a).
(3)For FGD wastewater requirements only,an initial commissioning period for the
treatment system to optimize the installed equipment.
(4)Other factors as appropriate.
40 C.F.R. §423.11(t).
The wastewater treatment systems at Roxboro will undergo significant modifications and in most
cases complete replacement to comply with the revisions to the ELG Rule.Duke would like sufficient
time to select, design and install the most cost effective technology at Roxboro to comply with the
ELG limits and reduce the burden to the ratepayers. We have prepared a preliminary timeline for
planning, designing, procuring, constructing and optimizing the technology once it is selected, for
each applicable waste stream. Based on our preliminary analysis, we request the following
applicability dates:
— Bottom Ash Transport Water: To convert the wet bottom ash transport system at Roxboro to
a closed loop system, Duke plans to install a remote mechanical drag chain system (RMDS).
Duke would like to request April 30, 2021 as the applicability date for the no discharge of
bottom ash transport water, assuming a permit effective date of October 1, 2016. Duke
anticipates that equipment will be installed by December 31, 2019 to comply with the North
Carolina-Coal Ash Management Act(NC-CAMA) and the Coal Combustion Residual (CCR)
rule. These rules, however, only regulate the material, not the water. As discussed below,
Duke will need a 16 month window to optimize the system to operate as a zero discharge

system. This additional time is needed to account managing the installation and optimization
of four RMDS being installed in N. Carolina simultaneously. In addition, the extent and
complexity of the permits required are unknown at this time. Duke, therefore, allocated 6
months to account for potential permitting delays.
FGD wastewater: Duke is reviewing options to determine whether the FGD wastewater
system at Roxboro will need to be completely replaced or if existing components can be
utilized. In addition,to construct a cost effective system,Duke is evaluating options to reduce
the FGD flow to the treatment system. Furthermore, it has come to Duke's attention the
availability of biological treatment systems may be limited due to intellectual property rights
be claimed by GE, which would limit the available vendor resources to supply the model
technology. At a minimum, we plan to evaluate the development of a new physical/chemical
system augmented by a selenium reduction system. To account for the multiple evaluations
needed and the limited vendor resources, Duke would like to request December,31,2023 as
the applicability date for the best available technology(BAT) limits for FGD wastewater.
— Fly Ash Transport Water: Fly ash is handled dry during normal operation; therefore, Duke is
not requesting an applicability date for the zero discharge of fly ash transport water beyond
November 1,2018.
The following provides necessary information justifying the requested applicability dates provided
above.
B. Bottom Ash Transport Water
As stated above, significant portions of the bottom ash transport system at Roxboro will need to be
replaced to comply with the no discharge limit of bottom ash transport water (BATW). The rule
identified dry handling or closed-loop systems as the BAT technology basis for control of pollutants
in bottom ash transport water. Specifically, a mechanical drag system (MDS) was identified as the
technology basis for a dry handling system, where as a RMDS was identified as the technology basis
for a closed-loop system. Duke is planning on installing a RMDS at Roxboro to handle bottom ash
dry.The system will be designed to operate in a closed-loop mode to meet the zero discharge limits
for BATW. Duke anticipates 55 months from the effective date of the permit will be needed to
design, install and commission the RMDS as a zero discharge system based on the following
preliminary timeline. It is important to note Duke will be installing RMDS at four stations in N.
Carolina; therefore, additional time is needed compared to a single installation to account for
managing multiple projects simultaneously.
Remote Mechanical Drag System(RMDS)
Activity Duration (Months)

Design' 8
• Siting 3
• Engineering 5
Procurement _ 12
Potential Permitting Delays 6
Construction/Tie-in 13
Optimization&Operational Experience2 16
• Commissioning 2
• Start-Up 6
Tota I: 55
1)The design tasks has been initiated and Duke estimates an additional 8 months from the
permit effective(assuming Oct. 1,2016)will be needed to complete the design.
2)Even though is it estimated that commissioning and start-up can occur in 8 months, Duke
anticipates needing a 16 month window to obtain the necessary operating time at full load
and account for commissioning/optimizing occurring at multiple facilities simultaneously.
Assuming a permit effective date of October 1, 2016, Duke estimates the system can be installed
and operated to comply with the zero discharge limit of BATW on or before April 30, 2021. To
design, procure, construct and optimize the RMDS at Roxboro to operate as a closed-loop system,
the following steps must be taken:
Design& Engineering
Duke has initiated the design phase, but, due to the simultaneous implementation of programs,
such as the CCR Rule and NC-CAMA across applicable sites in North Carolina, engineering and
technology resources are limited. Duke,therefore, estimates the design and engineering process will
take an additional 8 months from the permit effect date. Some of the activities within the water
balance and siting task will occur concurrently; however the design cannot be completed until the
siting task is completed. The permitting process, if necessary, will be initiated in the design and
engineering phase, but it is assumed permit receipt/ approval will be conducted concurrently with
the design and procurement phase and will be completed prior to the construction phase. The
following tasks will need to be completed.
Water Balance
The first step in the design process of the RMDS is to develop a detailed water balance of the
current BATW. To operate the system as a zero discharge system, there is a balance between the

inputs of water into the system and the outputs of water through evaporation and bottom ash
removal.This is necessary to determine if any additional treatment of the BATW is needed to avoid
increase in fines and concentration of other constituents that could affect equipment operability.
In addition, several non-BATW waste streams are currently commingled and treated along with
BATW. The flow of these waste streams will be rerouted from the BATW system to a new
wastewater treatment system.This will require the streams to be characterized for both volumetric
flow and constituent make-up in order to size and design an appropriate treatment system. It is
important to note that not all waste streams discharge continuously or simultaneously. Some waste
streams discharge intermittently based on activity occurrence, such air preheater and precipitator
washes, while others may only discharge under certain rainfall events. In addition, many waste
streams do not discharge if the unit is not running. With most coal-fired units operating in an
infrequent mode, the opportunities to collect samples are limited and the operation schedule could
affect the schedule of this task.
Upon completion of the water balance, detailed engineering of the RMDS system and piping
reroutes of non-BATW can commence.
Siting
The RMDS will need to be sited appropriately to avoid any historical or current coal combustion
product disposal (CCP) sites and avoid construction areas that will be used to complete closure of
the ash basins at Roxboro. In addition, Duke will attempt to site the system to avoid waters of the
U.S. (WOTUS). However, based on the final siting of the system, WOTUS may not be avoided, and
permits from the U.S.Army Corps of Engineers may be required.
Permitting
If WOTUS cannot be avoided,then permitting from the U.S.Army Corps of Engineers(USACE)will be
needed. At this time, it is unknown whether a USACE permit will be required or the type of permit
that may be required (nationwide permit(NPW) or individual permit). Duke,therefore, has included
12 months in the schedule to prepare and obtain any necessary USACE permits.
Once the RMDS is commissioned,the permitted discharge flows will change drastically.The amount
of water discharged could be reduced by as much as 85%. In addition, these flows typically were
ash basin. Duke, therefore, will need to design,treated along with the BATW in the g , and construct a
new treatment system for these low volume wastes. The size and technology of the treatment
system will be determined based on the water characterization study discussed above. In addition,

based on the final siting of the low volume wastewater treatment system, a new outfall may be
needed for the discharge of the effluent from this new wastewater treatment system. With
significant changes to the characteristics of the permitted discharge, Duke anticipates a NPDES
permit modification will be required to revise the permit to account for the changes in flow and
constituent make-up.
Even though the permitting task will be initiated during the design and engineering phase, it is
expect to continue through the procurement phase and up to the construction phase. In addition,
the extent and complexity of the permits required are unknown at this time. The required permits
will be evaluated during the engineering and design phase. Since the time needed to prepare the
permit applications and the time needed to receive the permits is uncertain, Duke allocated 6
months to account for potential permitting delays.
Procurement
After the design is complete, Duke will initiate the process to procure the necessary outside
resources to construct and install the new wastewater treatment systems. This process will involve
the following steps:
— Evaluate potential vendors for proposal solicitation;
— Develop and submit request for proposal (RFP)to selected vendors;
— Conduct a review and vendor selection based on the received bids;
- Develop required contract documents;
- Acquire materials(potentially from overseas),which involves:
o Shipment,and
o Equipment Fabrication
— Fabrication and inspection of equipment.
RMDS have a fabrication queue that is dependent on total industry-wide demand. Duke, therefore,
has allocated 12 months to acquire the necessary materials.
Construction
Once all the necessary materials are procured, Duke estimates construction of the RMDS will take
approximately 13 months. In addition, the tie-in of the RMDS to each individual generating unit will
need to occur during outages,which are anticipated to occur between March to May and October to
November depending on generation demand.
Optimization and Operational Experience

As stated above, Duke is planning to have the equipment installed by December 31, 2019 at the
latest to meet the obligations under CAMA, in addition,to any CCR requirements.Again, these rules
regulate the bottom ash material, not the transport water. Given the system will continue to utilize
water to transport bottom ash,time will be needed to gain operational experience and optimize the
system to meet the zero discharge limit. Duke estimates a 16 month window will be required to gain
the necessary operational experience and fine-tune the system. The 16 month window is estimated
based on the potential that the station may only be operating at full load during the winter and
summer months and load and account for commissioning/optimizing occurring at multiple facilities
simultaneously. In addition, with NCDEQ approving the implementation date of January 31, 2021 for
Marshall Steam Station, Duke would like to stagger the commissioning / optimization activities for
Roxboro by 3 months.
C. New Wastewater Treatment System
As discussed above, with the removal of several non-BATW waste streams from the bottom ash
transport system, a new wastewater treatment system will need to be designed and constructed for
co-treatment of low volume waste and other regulated process streams per the CCR rule, ELGs, and
NDPES permitting requirements. The activities associated with the new wastewater treatment system
will be conducted concurrently with the other design activities at the site. These waste streams are not
subject to the applicability date in the ELG rule,therefore, Duke is not requesting a compliance date,
but this task will need to be completed prior to the effective date of the zero discharge of BATW.
Duke anticipates 30 months will be needed to design, install and commission the new wastewater
treatment system, based on the following preliminary timeline.
New Wastewater Treatment System
Activity Duration(Months)
Siting 3
Engineering 6
Procurement 3
Construction/Tie-in 9
Commissioning 3
Start-Up 6
Total: 30
D. FGD Wastewater
Duke expects significant capital improvements to the FGD wastewater treatment system will be
needed to meet the ELG limits. At a minimum, Duke anticipates having to install a new tank-based
physical / chemical treatment system followed by a selenium reduction technology. The selenium
reduction technology has not yet been selected and Duke will be evaluating suitable technologies

based on cost and feasibility.A biological treatment system is currently installed at Roxboro, but the
ELG limits cannot be achieved with the current system. Duke will evaluate the current biological
treatment system to determine whether the system can be used as part of an upgraded treatment
system or will need to be discarded and completely replaced.
In addition, the FGD flow rate for Roxboro is estimated at approximately 1,094 gallons per minute
(gpm). In the proposed ELG rule, EPA assumed Roxboro could reduce its FGD flow to 375 gpm by
recirculating some of the FGD water back to the FGD system. This would allow for the design of a
significantly smaller system, resulting in a significant reduction in cost. Duke is evaluating options to
reduce the FGD flow,which would affect the technology selection,design and cost of the system.
To further complicate matters, EPA's model technology for the treatment of FGD wastewater is
physical/chemical followed by biological treatment. Recently, the biological treatment system
vendor for the ABMet system, GE, has claimed intellectual property rights on all biological treatment
technologies for FGD wastewater. This could have significant impacts on the cost and procurement
schedule of the treatment system.With an EPA estimate of 88 stations within the industry expected
to upgrade the FGD wastewater treatment system to comply with the ELG limits, the
implementation date must take into account limited resources of EPA's chosen model technology.
EPA recognizes that designing, procuring, installing, and optimizing an FGD wastewater treatment
system is a complicated and time-consuming undertaking, involving much study and careful
planning. For example, EPA states:
"For plants that are planning to include fuel flexing in their operations, in the years
prior to the installation and operation of the FGD wastewater treatment system,the
plant should consider sampling the untreated FGD wastewater to evaluate the
wastewater characteristics that are present based on the differing fuel blends. Based
on those characteristics, the plant will be better able to design a system that can
properly treat its FGD wastewater given variability that might occur at the plant, and
it will be better prepared to adjust chemical dosages in the chemical precipitation
system to mitigate the variability in the wastewater that enters the biological
treatment system."
Response to Comments, p.5-387.
EPA also states:
"While EPA has based the effluent limitations and standards for selenium and
nitrate/nitrite (as N)for FGD wastewater based on the performance of the Allen and
Belews Creek biological treatment systems, EPA does not contend that every plant in

r
the industry can simply take the design parameters from those two plants, install the
biological treatment system, and meet the effluent limitations. Each plant will need
to work with engineering and design firms to assess the wastewater characteristics
present at their plant to determine the most appropriate technologies and design the
system accordingly meet the effluent limitations. Therefore, some plants may need
to design the bioreactors to provide additional bed contact time (as provided by the
hydraulic residence time and volume of biomass and carbon substrate), while other
plants may find they need less."
Response to Comments, p. 5-389
Duke is requesting 87 months from the effective date of the permit to design, install and
commission the FGD wastewater treatment system to meet the BAT limits based on the following
preliminary timeline.
FGD WWT Upgrade
Activity Duration(Months)
Design&Engineering 30
• Flow Reduction Evaluation 6
• Evaluation of the existing
biological system 6
• Technology Evaluation 8
• Siting 4
• Engineering 6
Procurement' 20
Potential Permitting Delays 6
Construction/Tie-in' 16
Start-up&Optimization2 15
• Commissioning 6
• Start-Up 6
Total: 87
1)Duke is allocating a 20 month window for procurement and a 16 month window for
construction and tie-in to account for only one vendor available to supply and construct the
biological treatment system.
2) Duke is allocating a 15 month window to complete the commissioning and start-up under
all expected operating conditions from full load to partial load to periods of no load.

Assuming a permit effective date of October 12016, Duke estimates the system can be installed and
commissioned to meet the BAT limits on or before December 31, 2023. To design, procure,
construct and commission the FGD WWT system at Roxboro,the following steps must be taken:
Design & Engineering
As with the RMDS,engineering and technology resources are limited due to regulatory
requirements for concurrent implementation of programs,such as the CCR Rule and NC-CAMA
across applicable sites in North Carolina. Duke is,therefore, estimating 30 months to complete the
design and engineering phase of the project.
FGD Flow Reduction Evaluation
Duke is evaluating options,such as recirculating some of the FGD water back to the FGD system,to
reduce the FGD wastewater flow rate to design and install a cost effective system.As stated above,
EPA assumed Roxboro could reduce the FGD wastewater flow to 375 gpm.Whether recirculating
some of the FGD water back to the FGD system is a viable option is dependent on the chlorides in
the FGD water and chloride impacts on the materials of construction of the FGD scrubber. Duke will
also determine if other flow reduction measures are available for Roxboro.This is a critical step in
the design and technology evaluation to ensure a cost effective treatment system.
Existing Bioreactor Evaluation
A biological treatment system is installed at Roxboro. However,the current system cannot meet the
final ELG limits for FGD wastewater.Currently, it is unknown whether the existing biological
treatment system can be used as part of an upgraded treatment system or if the biological
treatment system will need to be discarded and completely replaced. Duke,therefore, is planning
on conducting an evaluation to determine the feasibility and cost of using the existing biological
reactor or replacing the entire system.
Siting
As with the RMDS, the FGD WWT system will need to be sited to avoid any former or current CCR
sites and avoid construction areas that will be used to complete closure of the ash basins at
Roxboro.Additionally, Duke will need to site the system to avoid nuisance odor outside the property
boundary. Duke will also attempt to site the system to avoid WOTUS. However, based on the final
siting of the system WOTUS may not be avoided, and permits from the U.S.Army Corps of Engineers
may be required.
Technology Selection

•
Duke has significant experience in the design,construction and operation of biological treatment
systems for selenium reduction. Based on Duke's experience, biological treatment alone may not be
a fool proof technology based on the characteristics of the coal. Duke,therefore, is obligated to
review and evaluate whether other suitable technologies are available to treat FGD wastewater for
selenium reduction at Roxboro.This is particularly important with GE claiming intellectual property
rights on the biological treatment system for FGD wastewater,thus being the sole provider of this
technology. Duke will be working closely with utility organizations, such as the EPRI,to identify
suitable technologies for the removal of selenium from FGD wastewater and possibly additional
polishing steps that may be required to meet the limits.
Upon completion of the siting and technology selection,the engineering design of the system will be
completed.
Permitting
If WOTUS cannot be avoided,then permitting from the U.S.Army Corps of Engineers(USACE)will be
needed. At this time, it is unknown whether a USACE permit will be required or the type of permit
that may be required (nationwide permit (NPW) or individual permit). Duke,therefore, has included
12 months in the schedule to prepare and obtain any necessary USACE permits.
The installation of the FGD WWT may change the characteristics of the final discharge, therefore, a
NPDES permit modification may be required to revise the permit to account for the changes in flow
and constituent make-up.
Even through the permitting task will be initiated during the design and engineering phase, it is
expect to continue through the procurement phase and up to the construction phase. In addition,
the extent and complexity of the permits required are unknown at this time. The required permits
will be evaluated during the engineering and design phase. Since time needed to prepare the permit
applications and the time needed to receive the permits is uncertain, Duke allocated 6 months to
account for potential permitting delays.
Procurement
After the design is complete, Duke will initiate the process to procure the necessary outside
resources to construct and install the new wastewater treatment systems. This process will involve
the following steps:
— Evaluate potential vendors for proposal solicitation;
— Develop and submit a request for proposal(RFP)to selected vendors;
— Conduct a review and vendor selection based on the received bids;

Develop required contract documents;
— Acquire materials(potentially from overseas), which involves:
o Shipment, and
o Equipment Fabrication
— Fabrication and inspection of equipment.
The selenium reduction technology will have a fabrication queue that is dependent on total
industry-wide demand. With GE claiming intellectual property rights on biological treatment
additional time will need to be factored into the implementation date. Duke, therefore, has
allocated 24 months to acquire the necessary materials. Additionally, raw materials needed may
have an extended lead-time from time of order to delivery, such as the granulated activated carbon
used in the biological system, which has a lead time of 12 months. As stated above, GE is claiming
intellectual property rights on the biological treatment system. If this claim is upheld, GE will be the
only supplier of the biological treatment system. Given the potential number of facilities installing
treatment system for FGD wastewater in the industry, additional 8 months is allocated to account
for an extended procurement period.
Construction/Tie In
Once all the necessary materials are procured, Duke estimates construction of the FGD WWT will
take approximately 16 months to complete. In addition, the tie-in of the FGD WWT to each
individual FGD scrubber will need to occur during outages, which are anticipated to occur between
March to May and October to November depending on generation demand. Furthermore, an
additional 4 months were included in the schedule to account for the potential of GE being the sole
provider of the biological treatment system.
Commissioning&Start-up
Duke estimates that commissioning and start-up of the FGD WWT will take 12 months to complete,
6 months for each task. Duke, however, is allocating a 15 month window to complete the
commissioning and start-up under all expected operating conditions from full load to partial load to
periods of no load.This will allow the identification of necessary actions that need to be completed
in order to maintain the system under different operating scenarios.
E. EPA Provided a Range of Applicability Dates To Allow For Coordination across Regulatory
Requirements and to Promote Orderly Decisions
The steam electric industry is in the midst of major transitions driven by new environmental
regulatory requirements in the air, waste, and water arenas. In the ELG Rule, EPA explicitly
acknowledged the complications of planning and executing ELG retrofits while developing and

executing compliance strategies under the other rules. EPA made it clear that the range of
applicability dates provided in the ELG Rule are supposed to be implemented in a manner that
avoids stranded costs and promotes orderly decision making. For instance, EPA states:
"From an environmental protection/coordination standpoint, with the increased use of
flue gas desulfurization scrubbers and flue gas mercury controls in response to air
pollution-related requirements, this rule makes sense from a holistic environmental
protection perspective and from the perspective of coordinating across rules affecting
the same sector. This final ELG controls the discharges associated with these particular
waste streams."
Response to Comments, p.8-388.
EPA also states that the permitting authority may "account for time the facility needs to coordinate
all the requirements of this rule, along with other regulatory requirements, to make the correct
planning and financing decisions, and to implement the new requirements in an orderly and feasible
way." Response to Comments, p.8-129.
At Roxboro, we need to coordinate our ELG implementation strategy with CCR and NC-CAMA rules.
For both the CCR and CAMA rules, we are evaluating the current CCR ash ponds to determine
whether the ponds meet the locational restrictions of 40 C.F.R. § 257.60- .64. The future of the ash
pond under both of these rules will determine whether it is available or not to receive legacy
wastewaters (i.e., those wastewaters generated before the applicability date for bottom ash
transport water retrofits) and continue to receive non-BATW. In addition, as discussed above, the
final determination of the extent of the ash pond, as well as the closure method could have
significant ramifications for the siting of both the RMDS and FGD WWT.
F. ELG Implementation Should be Coordinated with the Clean Power Plan(CPP)to Avoid Stranded
Costs
The ELG Rule clearly contemplates that the compliance timelines for its requirements should
account for any applicable obligations under the CPP. However, the affected units at Roxboro will
not know their individual obligations under the CPP until well after November 1, 2018. As
promulgated by EPA, the CPP's emission guidelines do not apply directly to units. Instead, states are
responsible for developing state plans setting forth requirements applicable to individual units that
implement those emission guidelines. These state plans are subject to review and approval by EPA.
If EPA determines that the state has not submitted an approvable plan, then EPA will promulgate a
federal plan in its place. The timeline the CPP provides for developing and reviewing these state
plans involves numerous steps.

The initial deadline for state plan submittal was September 6, 2016. 40 C.F.R. § 60.5760(a). The vast
majority of states were expected to seek and obtain a two-year extension for final state plan
submittal until September 6, 2018. See id. §60.5760(b). However, the Supreme Court issued a stay
of the CPP on February 8, 2016.Thus,the timing of the requirements of the CPP is uncertain at this
time, as we wait further decisions by the Supreme Court. Duke would like to request the option to
revise the applicability dates for the ELG requirements if the stay of the CPP is lifted and the
operation of Roxboro will be affected.
Statements in the Response to Comments regarding stranded costs apply to any rule, not just the
CPP. EPA explains in the Response to Comments that it provided flexibility in applicability dates so
that facilities could consider all new regulatory requirements and then have an adequate time to
plan and implement accordingly,and thus avoid stranded costs:
"EPA is sensitive to the need to provide sufficient time for steam electric power plants
to understand, plan for, and implement any changes to their operation to meet their
environmental responsibilities, and agrees with the commenter that transparency of
requirements is important for minimizing "stranded investments." ...Furthermore, as
described in the preamble, the final rule provides time for plant owners or operators to
implement changes to plant operations in order to meet the final limitations and
standards, as well as flexibility to permitting authorities in implementing the final rule.
The Agency specifically considered the timing of requirements of other environmental
regulations in establishing implementation requirements for the ELGs, in order to
provide steam electric power plants time to consider and implement their strategy for
compliance."
Response to Comments, p. 8-388.
Even though the implementation and effects of the CPP are uncertain, North Carolina Department
of Environmental Quality (NCDEQ) is justified providing flexibility in the applicability dates from
other regulatory requirements such as the CCR and NC-CAMA, as discussed above.
G. The Proposed Schedules Help to Maintain Roxboro's Availability to the Grid,Which Promotes Grid
Reliability
Duke developed the proposed BATW retrofit schedule and its applicability date with grid reliability
in mind. The dispatch of units at Roxboro varies throughout the year. Typically one unit is operating
throughout the year and all four units are typically dispatched from December to March and June
thru September. Therefore, the final tie-in schedule will avoid these months and more than likely
tie-ins will need to occur across more than one outage.

EPA explicitly notes that the permitting authorityshould consider grid reliability in setting
applicability dates: "EPA's decision is also designed to allow, more broadly, for the coordination of
generating unit outages in order to maintain grid reliability and prevent any potential impacts on
electricity availability, something that public commenters urged EPA to consider." 80 Fed. Reg. at
67,854,col.2. See also Response to Comments, p. 8-138.
Also, EPA clearly anticipated that much of the new technology required for retrofits to bottom ash
transport water and FGD wastewater systems would be constructed in a manner that would not
interrupt routine facility operations, and then tied in during regularly scheduled plant or unit
outages. According to the preamble,the timing of the final rule "enables facilities to take advantage
of planned shutdown or maintenance periods to install new pollution control technologies." 80 Fed.
Reg.at 67,854,col. 2.
EPA also recognizes that tie-ins of new equipment may need to occur across more than one outage.
EPA states: "the need to span installation of equipment over separate unit outages [is] a
consideration that can be incorporated into the permit writer's determination of the 'as soon as
possible' date, assuming the plant provides documentation demonstrating such a need." Response
to Comments, p.8-54.

Attachment 5
Clean Water Act 316(b) alternate schedule request
August 15, 2016 NPDES application update
Roxboro Steam Plant
NC0003425

Alternate Schedule Request§316(b) of the Clean Water Act
Roxboro Generating Station
Final regulations to establish requirements for cooling water intake structures at existing
facilities were published in the Federal Register on August 15, 2014 (i.e. regulations
implementing §316(b) of the Clean Water Act) with an effective date of October 14, 2014. Per
§125.91(a)(1)-(3) Applicability, the Roxboro Generating Station (Roxboro) is subject to the
requirements at§125.94 through§125.99(316(b)requirements)based on the following:
— The facility is defined as an existing facility (i.e. commenced construction prior to
January 17, 2002);
— The facility is a point source discharge;
— The facility uses a cooling water intake with a design intake flow (DIF) of greater than 2
million gallons (MGD)to withdraw water from waters of the U.S.; and
— Twenty-five percent or more of the water withdraws on an actual intake flow basis are
exclusively used for cooling purposes.
Per §125.98(b) Permitting requirements, 316(b) requirements are implemented through the
NPDES permit. Facilities subject to the final rule are required to develop and submit application
materials identified at §122.21(r). The actual intake flow (AIF) of the facility determines which
submittals will be required. All facilities with an DIE 2 MGD or greater are required to submit
material identified at §122.21(r)(2)-(8), whereas, facilities with an AIF greater than or equal to
125 MGD are required to submit additional information presented in §122.21(r)(9)-(13). The
AIF withdrawn by the station from Hyco Reservoir is above the 125 MGD threshold; therefore,
Duke Energy is planning on completing the following 316(b) submittals:
• §122.21(r)(2) Source Water Physical Data
• §122.21(r)(3) Cooling Water Intake Structure Data
• §122.21(r)(4) Source Water Baseline Biological Characterization Data
• §122.21(r)(5)Cooling Water System Data
• §122.21(r)(6) Chosen Method(s) of Compliance with Impingement Mortality Standard
• §122.21(r)(7)Entrainment Performance Studies
• §122.21(r)(8) Operational Status
• §122.21(r)(9)Entrainment Characterization Study
• §122.21(r)(10)Comprehensive Technical Feasibility and Cost Evaluation Study
• §122.21(r)(11)Benefits Valuation Study
• §122.21(r)(12)Non-water Quality and Other Environmental Impacts Study
• §122.21(r)(13) Peer Review

Per §125.98(b) Permitting requirements, 316(b) requirements are implemented through the
NPDES permit. For Roxboro, the NPDES permit proceedings had begun prior to the effective
date of the rule. Therefore, 40 C.F.R §125.98(g) Ongoing permitting proceedings, applies to
Roxboro, which states:
"... whenever the Director has determined that the information already submitted by
the owner or operator of the facility is sufficient, the Director may proceed with a
determination of BTA standards for impingement mortality and entrainment without
requiring the owner or operator of the facility to submit the information required in
40 CFR 122.21(r).."
Only limited information regarding 316(b) was previously submitted to NCDEQ for
Roxboro. The previously submitted information consisted of a Proposal for Informational
Collection (PIC) request and a 316(b) Barrier Net Conceptual Design Report. In Duke's opinion,
the previously submitted information is not sufficient for NCDEQ to proceed with a
determination of BTA standards for impingement mortality and entrainment. As stated in the
preamble to the rule, "In such circumstances where permit proceedings have already begun prior
to the effective date of the rule, these facilities will still need to submit the appropriate permit
application materials found at § 122.21(r)permit applications during their next application." 1
Furthermore, the regulation states the owner of a facility whose current effective permit
expires after July 14, 2018, must submit the above information when applying for a subsequent
permit and the owner of a facility whose current effective permit expires on or before July 14,
2018 may request an alternate schedule for the submission of the above information . As
allowed under §125.95(a)(2) and stated in the preamble to the rule, Duke Energy would like to
request an alternate schedule for the submittals listed above. Duke Energy would like to request
the 316(b) submittals, with the exception of sC122.21(r)(6) Chosen Method(s) of Compliance with
Impingement Mortality Standard, for Roxboro be required with the subsequent permit renewal
application due after July 14, 2018. Since Roxboro is subject to the entrainment best technology
available (BTA) determination, a compliance schedule to complete §122.21(r)(6) Chosen
Method(s) of Compliance with Impingement Mortality Standard will be requested to be included
in the permit upon issuance of the entrainment BTA determination. The alternate schedule
request is justified based on the following:
— Roxboro was not required to submit information requested in §122.21(r)(2), (3), (4)
and(5)under the remanded Phase II Rule because the station was planning to comply
by installing a barrier net to meet the through screen velocity limit.
— Information requested in §122.21(r)(6) — r(12) are new provisions and these
submittals must be developed with r(9)requiring two years of entrainment data.
i 79 Fed. Reg. 48358(15 August 2014)
2 Refer to§125.95(a)(1)and(2)

— For the §122.21(r)(13) Peer Review, Duke Energy estimates this could take up to 12
months to complete. This, also, takes into account the other six Duke Energy stations
in N. Carolina and two stations in S. Carolina that will be undergoing the peer review
process concurrently.
— Additionally, the United States Environmental Protection Agency (USEPA) —
Headquarters (HQ) have indicated guidance is being prepared to assist in interpreting
and implementing the rule requirements, however, this guidance is not expected to be
issued until the 316(b) litigation is completed, which is not expected to occur until
2017.

Attachment 6
Process flow diagram with proposed future water
flow path
August 15, 2016 NPDES application update
Roxboro Steam Plant
NC0003425

Roxboro Steam Electric Plant Post ash basin flow outfall 003
Plant Process Plant Drainage
Streams > System
A
Drains from oil
filled H
equipment X_ Domestic Sewage
containment r Low Volume Waste Treatment Plant Hyco
A 'Collection Sump Reservoir
Water Treatment Treatment
Systems (Oil/Water P
Separator) {
Emergency Flue Gas
Discharge Desulfurization
NH3 Vapor v I II,
)Unit 4 Cooling Unit 4 Cooling To Atmosphere Suppression Lined BioP/C, FGD
Water 4—A— Tower D (Emergency) Retention l'' Ultra"(
*Option, Blowdown
Outfall 005(internal) r basins filtration OR
ZI t (east and \ l OR 1
Fa) Maintenance Drain Ash Landfill west)
a
iY Leachate f East West
o� settling �.... settling
and SW
i Stormwater See pond pond
—To Atmosphere A
o B Unit 3 Cooling Unit 3 Cooling below
LL } Water' Tower
E Silo F Unit 3 Cooling tt w m a
'Alternative modes G Wash Water Tower Pond Bioreactor w o
Outfall 002(internal)
A Zr
Stormwater from Outfall 010 Flush
Gypsum Storage Pile Area -- ~ �� O pond
C Unit 1 &2 Heated Water Ash basin closure flows
Cooling Water Mixing Zone M Hyco
Reservoir Evaporation
Stormwater } Effluent Channel Outfall 003
Form 2C—Item II A Flows,
Sources of Pollution,and
AOW's and seeps From Lined* Treatment Technologies
retention Outfall 003 August 2016
basins above

Roxboro Steam Plant Outfall 006
Raw water
tank drainage
Stormwater (maintenance)
Coal Pile Runoff Treatment Basin Outfall 006
>Hyco Reservoir
A
Limestone pile runoff
Emergency Gypsum Truck wheel wash
stack
Form 2C—Item II A Flows,
Sources of Pollution,and
Treatment Technologies
Outfall 006 August 2016

•
Roxboro Steam Plant Outfall 001
Stormwater
through remnant
of east ash basin
y Outfall 001 Intake pumps for
> Plant Intake Canal —> plant processes
Incidental
AOW's and Gypsum and rail
seepage runoff
Outfall 003
Form 2C—Item II A Flows,
Sources of Pollution,and
Treatment Technologies
Outfall 001 August 2016