NC0005088_Supplemental Information for Renewal Application_20160902

i
DUKE Harry K.Sideri
ENERGY® Senior Vice President
Environmental,Health&Safety
526 S. Church Street
Mail Code:EC3XP
Charlotte,NC 28202
[phone]
August 31, 2016
Ms.Teresa Rodriquez RECEy ; �,}C ,,tQ/®VV
North Carolina Division of Water Resources
1617 Mail Service Center SEP — D 2016
Raleigh, NC 27699-1617 ,ft
Subject: Supplemental Information for Current Eeimitting Section
NPDES Wastewater Permit Application and Requests
Duke Energy Carolinas, LLC.
Rogers Energy Complex
Permit#: NC0005088
Cleveland & Rutherford Counties
Dear Ms. Rodriquez:
Duke Energy Carolinas, LLC (Duke) is submitting supplemental information in support of the Rogers
Energy Complex's NPDES permit renewal application previously submitted on January 28,2015.
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 (NC-CAMA)
of 2014 and HB 630 of 2016.
Information is provided for a future wastewater treatment system and its outfall (005), an emergency
overflow outfall (002B)from a new Holding Cell, an emergency overflow outfall (002C) from a future
Holding Basin, updated seeps information, a request with justification for alternate applicability dates for the
Steam Electric Effluent Guidelines and an alternate schedule request for section 316 (b) of the Clean Water
Act. Revised site and flow diagrams are attached.
This submittal updates several items in the previous applications and requests submitted on July 28, 2014,
October 31, 2014, December 17, 2014, January 28, 2015 and March 7, 2016. Please include this
supplemental information along with the previous updates and requests in your review.
We appreciate your attention to these requests and look forward to finalizing the NPDES permit for the
Rogers Energy Complex in the near future. Should you have any questions regarding this letter or require
additional information, please contact Mr. Robert Wylie at [phone] or at Robert.Wylie@duke-
energy.com.

"1 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. l am aware that there are significant penalties for
submitting false information, including the possibility of fines and imprisonment for knowing violations."
Sincerely,
qAn '�Z�
Harry Sideris
SVP - Environmental, Health &Safety
Attachments:
Supplemental Information Package
Attachment A—Site Plan
Attachment B— NPDES Outfalls
Attachment C— Process Flow Diagram
Attachment D— Final WWTS Influent/Effluent Characteristics
Attachment E—Effluent Guidelines Rule Justification for Applicability Dates
Attachment F—Position Paper Mechanical Drag System
Attachment G—Alternate Schedule Request§316(b) of the Clean Water Act
Attachment H—NPDES Seeps

Duke Energy Carolinas, LLC.
Rogers Energy Complex
NPDES Permit # NC0005088
Supplemental Information Package
August 31 , 2016

;
Duke Energy Carolinas,I.I.C.
Rogers Energy Complex
NPDES PERMIT#NC0005088
Supplemental Information Package
Duke Energy Carolinas, LLC.
Rogers Energy Complex
NPDES Permit#NC0005088
Supplemental Information Package
Introduction and Background
Duke Energy(Duke) is submitting this supplemental information in support of the NPDES renewal
application previously submitted. 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 Limitations Guidelines(ELG), Federal Coal Combustion Residual(CCR) rule,the North Carolina
Coal Ash Management Act of 2014 and HB 630 of 2016.
Supplemental information is also provided for the following: (See attachment A entitled Site Plan)
1. A new Final Wastewater Treatment System (WWTS)and requested new Final WWTS Outfall 005
2. A new emergency yard sump overflow from Holding Cell Outfall 002B
3. A new emergency overflow for significant rain events from Holding Basin Outfall 002C
4. Updated seeps information
5. A request and justification for alternate applicability dates for the Steam Electric Effluent
Guidelines.
In total there will be five outfalls 002, 002B, 002C, 004 and 005. Outfall 002A will be replaced by 002B and
002C. (See attachment B entitled NPDES Outfalls)
Revised site and flow diagrams are included as attachments.
This submittal is in addition to the previous applications and requests submitted dated July 28, 2014,
October 31, 2014, December 17, 2014, January 28, 2015 and March 7, 2016. Duke is requesting that all of
these submissions be included during the permit renewal process.
Outfall 002
North Carolina's Coal Ash Management Act and the Federal CCR rule will prohibit continued wastewater
flows to the existing ash basin at Rogers Energy Complex. Projects are underway or will be in the future to
convert ash handling for all ash (both bottom ash and fly ash)to dry handling and disposal systems. All
other wastewater inputs to the current ash basin will be redirected to a future Waste Water Treatment
System (Outfall 005). See attachment C entitled Process Flow Diagram.
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Duke Energy Carolinas,LLC.
Rogers Energy Complex
NPDES PERMIT#NC000S088
Supplemental Information Package
Decanting and dewatering wastewater will be required for the ash basin closure. It is anticipated that
additional treatment may be needed prior to discharging to the Broad River. Duke is evaluating the use of
a temporary treatment system for discharging to Outfall 002 during decanting and dewatering activities.
Duke also wants the option to treat this wastewater in the future WWTS which discharges to Outfall 005.
Duke requests specific authorization for the decanting and dewatering of the ash basin to be added
to the NPDES permit with discharges at both Outfalls 002 and 005.
Outfall 002A
Outfall 002A will be eliminated and replaced by Outfalls 002B and 002C.
Outfall 002B
Duke plans to utilize an existing basement structure from the Powerhouse for former Units 1 through 4 as a
Holding Cell. Initially all the process and storm water that currently goes to the P-5 yard drainage basin will
be redirected to the Holding Cell. In the future the Holding Cell will just receive storm water runoff from
Units 5 and 6 plant areas and water treatment room wastewater. The water in the Holding Cell will be
pumped to the Final WWTS for treatment once the new WWTS is in operation. In the interim the water will
be pumped to the active ash basin Outfall 002.
During the ash removal from Units 1-4 retired ash basin,water will be pumped to the Holding Cell and then
to the active ash basin. During closure activities of the Unit 5's inactive basin any water that comes into
contact with exposed ash will be directed to the holding cell.
During significant rainfall events in order to minimize an overflow from the Holding Cell water will be
pumped from the Holding Cell to the new Auxiliary Basin. However, in very significant rainfall events(e.g.
100 year rainfall events)the Holding Cell may potentially overflow to the Broad River by way of an
emergency overflow. Duke requests a new Outfall 002B be added to the NPDES permit for the
Holding Cell emergency overflow discharge.
Outfall 002C
The P-5 yard drainage basin system currently receives all gravity fed flows including process waters. P-5 is
located on top of parts of the retired Unit 1 to 4 ash basin. To enable the full excavation and closure of the
retired Unit 1-4 ash basin, P-5 will be eliminated. In place of P-5 a new Holding Basin is being constructed.
The new Holding Basin will receive stormwater runoff from the coal yard, the gypsum and limestone
storage areas. Water from the Holding Basin will be pumped to the Final WWTS. The Holding Basin will
be equipped with an emergency overflow(Outfall 002C)which will discharge into the Broad river. Duke
reguuests a new Outfall 002C be added to the NPDES permit for the Holding'Basin emergency
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overflow discharge.
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Duke Energy Carolinas,I.I.C.
Rogers Energy Complex
NPDES PERMIT#NC0005088
Supplemental Information Package
Outfall 004
Outfall 004 currently is an internal wastewater treatment system outfall that discharges into the P-5 basin.
In the future this internal outfall will discharge into the future WWTS (outfall 005). To comply with Federal
ELG for Flue Gas Desulfurization (FGD)wastewater, an enhanced treatment system for FGD wastewater is
being evaluated. This system will potentially 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 at the facility's onsite landfill.
It is planned that Unit 6 will be converted to operate with natural gas as well as coal. During the mode of
operation by gas cooling water is needed to be added to the FGD system to protect the piping. Thus this
cooling water is planned to be routed to the FGD WWTS during this mode of operation. Duke intends to
install heat exchangers or small auxiliary cooling tower for influent flows to the new FGD WWTS. Service
water will be used to cool FGD wastewater prior to treatment in the biological system. Additional heat
exchangers or a small cooling tower will be utilized to assure process water remains below bioreactor
operational temperature requirements during the summer months. This addition is intended to assure
efficient operation of the FGD WWTS. The resulting non-contact cooling water may be combined with the
treated FGD wastewater after Outfall 004.
Outfall 005
Duke plans to install a new Final Wastewater Treatment System (Final WWTS). Inflows to the Final WWTS
will include the following specific sources:
1. FGD WWTS discharge(Outfall 004) and potential heat exchanger effluent
2. Landfill leachate
3. Water pumped from the Holding Basin (Stormwater runoff from the coal, gypsum and
limestone storage areas)
4. Low volume wastes
5. Cooling tower blowdown (units 5 and 6)
6. Wastewater from the under-boiler mechanical drag systems(MDS)for Units 5 and 6
7. Treated sanitary waste water
8. Water pumped from the Holding Cell (Unit 5 process water, Unit 5 stormwater, Unit 6
stormwater, Reverse Osmosis(RO) building floor drains)
9. Unit 5 yard sump
10. Unit 5 process sump
11. Unit 6 process water
12. Water from the Auxiliary Basin (Surplus flows from the Holding Cell)
13. Cooling water from FGD system during the Unit 6 operation by natural gas.
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Duke Energy Carolinas,I.I.C.
Rogers Energy Complex
NPDES PERMIT#NCoaoson
Supplemental Information Package
The Final WWTS will be a physical/chemical treatment system. This system will consist of flow
equalization, pH neutralization, coagulation and flocculation. The chemically treated water will be sent
through a series of high rate clarifiers and if necessary sent through polishing filters before being discharge
to new Outfall 005. The clarifier sludge and the backwash from the potential filters will be transported to a
thickener which will further increase the sludge concentration. This concentrated sludge will be sent to filter
presses to be dewatered and transported to the landfill. The thickener overflow and the filtrate from the
filter presses will be sent back to the beginning of the process. The plant's stormwater will be directed to a
series of storm water holding basins to attenuate the surge flows. This stormwater will be pump through
the physical/chemical treatment process at a controlled rate. The Final WWTS will discharge into the
Broad River through Outfall 005. A table showing the Final WWTS influent and effluent characteristics is
included in Attachment D entitled Final WWTS Influent/Effluent Characteristics. Duke requests a new
Outfall 005 for discharging treated wastewater to the Broad River be added to the NPDES permit for
the Final MTS.
Steam Electric Effluent Guidelines
Duke requests an alternate applicability date for the Steam Electric ELGs in accordance with the request
found in Attachment E. Fly ash and bottom ash transport water are generated by the operation of Unit 5
and sluiced to the ash pond treatment system and subsequently discharged through outfall 002.A
mechanical drag system(submerged mechanical flight conveyor) is used to handle bottom ash generated
by the operation of Unit 6. Per EPA's definition, a mechanical drag system (MDS) is considered a dry
bottom ash system, and thus does not generated bottom ash transport water. See Attachment F for details
on the applicability of the ELGs to MDS. Blowdown from the Unit 5 wet FGD and any unused blowdown
from the Unit 6 wet FGD is treated by the FGD wastewater treatment system and discharged to the ash
basin treatment system. The new ELG Rule (80 Fed. Reg. 67,838(Nov. 3, 2015))sets a range of possible
applicability dates for compliance with the new best available technology(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. Attachment E provides the appropriate
information justifying the following applicability dates:
• Bottom Ash Transport Water: To convert the wet bottom ash transport system at Rogers Energy
Complex(REC) Unit 5 to a dry bottom ash handling system, Duke plans to install a MDS. Duke
would like to request December 31, 2020 as the applicability date for the no discharge of
bottom ash transport water assuming a permit effective date of November 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 would
like a 12 month window to optimize the system. This additional time is needed to account for
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Duke Energy Carolinas,I.I.C.
Rogers Energy Complex
NPDES PERMIT#NCOOOS088
Supplemental Information Package
managing the installation and optimization of four remote mechanical drag systems (RMDS), as
well as the installation of the MDS at REC, simultaneously. As discussed in Attachment F, a MDS
does not generate bottom ash transport water. Any discharges from the MDS are classified as low
volume waste under the ELG rule. The zero discharge limits, therefore, for bottom ash transport
water are not applicable to Unit 6. Duke requests the discharges from the MDS be classified
as a low volume waste under the ELG rule and be included in the NPDES permit.
• FGD wastewater:Additional treatment will need to be added to the FGD wastewater treatment
system to meet the BAT limits for FGD wastewater. At a minimum, we plan to evaluate
enhancement of the existing physical/chemical system augmented by a selenium reduction
system. It has come to Duke's attention the availability of biological treatment systems may be
limited due to intellectual property rights being claimed by GE, which would limit the vendor
resources to supply the model technology. To account for uncertainty in vendor resources and
evaluate selenium reduction technologies other than biological treatment, Duke would like to
request December 31, 2023 as the applicability date for the BAT limits for FGD wastewater.
• Fly Ash Transport Water: Fly ash generated by the operation of Unit 6 is handled dry. For Unit 5,
dry fly ash conversion is in process and anticipated to be completed by the end of 2017. Duke,
therefore, is not requesting an applicability date for the zero discharge of fly ash transport
water beyond November 1, 2018.
Based on facts presented in the preamble to the ELG rule and the Technical Development Document
(TDD), a mechanical drag system (MDS)does not generate bottom ash transport water; therefore, the BAT
limitations of zero discharge of bottom ash transport water at are not applicable. Also, as stated in the
TDD, EPA recognizes water is used and wastewater is generated by a MDS, but this wastewater is not
bottom ash transport water. Therefore, any wastewater generated from the MDS should be classified as
low volume waste under the final ELG rule because it meets the definition of low volume waste: "The term
low volume waste sources means, taken collectively as if from one source, wastewater from all sources
except those for which specific limitations or standards are otherwise established in this part." MDS waste
are subject to limits for total suspended solids(TSS)and oil and grease(0&G). Duke requests the
discharges from the MDS be classified as a low volume waste under the ELG rule and be included
in the NPDES permit.
NC-CAMA and CCR Rule
Storm water flows from the existing landfill must be rerouted in order to comply with CAMA 2014 and the
Federal CCR rule. Currently, stormwater runoff from the landfill flows to the landfill leachate basin then
pumped to the Unit 6 process water system then to the P5 pond and then to the active ash basin for
treatment prior to being released through NPDES outfall 002. With the landfill expansion into Phase II,
landfill leachate generation will continue to increase. Storm water and landfill leachate will continue to be
pumped to the Unit 6 process water system. Unit 6 process wastewater will be rerouted and pumped to the
Final WWTS for treatment prior to discharge through Outfall 005. Duke requests that ELG permit limits
associated with landfill leachate be applied at Outfall 005.
Page 5 of 8

Duke Energy Carolinas,I.I.C.
Rogers Energy Complex
NPDES PERMIT#NC0005088
Supplemental Information Package
Although the site will have dry ash handling systems,other sources of wastewater that have contact with
ash are generated. These low volume wastes will be treated at the Final WWTS prior to being discharged
through Outfall 005. The information provided below provides examples and not intended to be all
inclusive.
Periodic ash transport area wash-downs and sump cleanouts in Units 5 and 6 generate wastewater
which is categorized as a low volume waste.
Truck routes for the fly ash loadout station are routinely washed down to minimize fugitive emissions
from truck wheel tracking and material accumulations. Trucks are rinsed off several times a day to
remove as from the windshields and the vehicles. At the end of each day, concrete areas are washed
down.
There are temporary wheel washers located throughout the site on service roads to remove ash and
other material from vehicle tires.
Vacuum trucks are used for cleaning and dewatering. Decanting areas are being installed at the
holding cell and the holding basin.
Electrostatic precipitator and preheater cleaning creates wastewater containing ash.
Quench water flows beneath each boiler in a trench and creates a bath and creates a seal for the boiler
gases and quenches the hot bottom ash as it falls from the boiler.Ash is removed by a mechanical
chain conveyor that drags along the bottom of the water filled trench. The mechanical chain conveyor
operates at an incline and dewaters the ash by gravity.The conveyor allows the water to drain back to
water bath. The boiler quench water overflows as process wastewater.
CWA Section 316(b)Alternate Schedule
Duke requested an alternate schedule for compliance with Section 316(b)of the Clean Water Act to be
extended to the next permit renewal application in the January 28, 2015 NPDES permit renewal
application. A copy of the request can be found in Attachment G entitled Alternate Schedule Request
§316(b)of the Clean Water Act.
SEEPs Categorization
Duke previously identified thirty five(35)Areas of Wetness(AOWs)within the site property. A map of AOW
locations is provided in Attachment H. AOWs S-1, S-5, S-7, S-8, S-9, S-20, S-24 and S-34 are requested
Page 6 of 8

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Duke Energy Carolinas,I.I.C.
Rogers Energy Complex
NPDES PERMIT N NC0005088
Supplemental Information Package
to be eliminated from the NPDES permit since their analytical values indicate they are not influenced by
CCR materials. AOWs 13, 23, 26 and 33 do not clearly discharge to the receiving water body and thus are
requested to be eliminated. S-19, 19a and 18 feed into seep S-2. S-22 feeds into S-6. A group of AOWs
S-21, 14, 15, 16 and 27 are all relatively close together. Another group of AOWs S-28, 29, 30, 31 and 32
are also relatively close together. It is proposed that one sampling location per group be selected that is
representative of these AOWs. These groups of AOWs discharge into Suck Creek which flows into the
Broad River upstream of the ash basin discharge. In summary it is requested that Seeps S-2,S-3,S-4,
S-6,S-10, S-11,S-12 and S-17 and also the two mentioned groups be designated as either effluent
channels or point sources.
Anhydrous Ammonia Water Spray Suppression System Modification
Duke plans to install a second water spray suppression system around the anhydrous ammonia tanks to be
used in the event of a release of anhydrous ammonia. This modification is intended to enhance the safety
of site personnel, local residents and emergency responders should there be a release. The system will be
tested periodically producing flows from Unit 6 and Unit 5 plant ammonia storage areas. In the event of an
actual emergency, operation of the system may result in ammonia saturated water(high pH). Under
normal operations,the resulting water will be directed to the Holding Basin then treated in the Final WWTS
(Outfall 005). It is not projected that this waste stream will significantly change the waste stream that
currently flows to the active ash basin and will flow to the Final WWTS in the future.
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Duke Energy Carolinas,I.I.C.
Rogers Energy Complex
NPDES PERMIT#NC0005088
Supplemental Information Package
List of Attachments:
i
Attachment A-Site Plan
Attachment B- NPDES Outfalls
Attachment C- Process Flow Diagram
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Attachment D- Final WWTS Influent/Effluent Characteristics
Attachment E-Effluent Guidelines Rule Justification for Applicability Dates
Attachment F-Position Paper Mechanical Drag System
Attachment G-Alternate Schedule Request§316(b) of the Clean Water Act
Attachment H-NPDES Seeps
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Duke Energy Carolinas,I.I.C.
Rogers Energy Complex
NPDES PERMIT R NC0005088
Sypplemenlal Information Package
Attachment A
Site Plan

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Duke Energy Carolinas,I.I.C.
Rogers Energy Complex
NPDES PERMIT#NC0005088
Supplemental Information Package
Attachment B
NPDES Outfalls

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Duke Energy Carolinas,LLC.
Rogers Energy Complex
NPDES PERMIT N NC0005088
Supplemental Information Package
Attachment C
Process Flow Diagram

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Duke Energy Carolinas,LLC.
Rogers Energy Complex
NPDES PERMIT N NCODOSOOG
Supplemental Information Package
Attachment D
Final WWTS InfluentlEffluent Characteristics

Final WWTS Influent/Effluent Protected Characteristics
Project Projected Units of
Sample Location Influent Effluent
Measure
Average Average
Ammonia(Colorimetric) 0.23 m -N/L
Nitrite+Nitrate(Colorimetric) 0.55 mg-N/L
Total Phosphorus(Colorimetric) 0.13 mg-P/L
Bromide 0.71 mg/L
Fluoride NO mg/L
Sulfate 69.00 mg/L
Total Aluminum(Al) 5.01 0.13 mg/L
Total Barium Ba 0.08 0.05 mg/L
Total Boron(B) 1.77 L1.4 mg/L
Total Chromium(Cr) 0.01mg/L
Total Copper(Cu) 0.011 mg/L
Total iron(Fe 4.81 mg/L
Total Magnesium(Mg) 12.10 mg/L
Total Nickel(Nf) 0.012 0.007 mg/L
Total Tin(Sn) NO NO mg/L
Total Titanium(Ti) NO NO mg/L
Total Zinc(Zn) 0.056 0.012 mg/L
Total Antimony(Sb) 2.01 2.06 ug/L
Total Arsenic As 9.50 2.68 ug/L
Total Beryllium(Be) 1.04 1:00, ug/L
Total Cadmium(Cd) 1.71 1.42 ug/L
Total Cobalt(Co) 5.81 3.93 ug/L
Total Lead(Pb) 5.64 ;190 ug/L
Total Manganese(Mn) 234 217 ug/L
Total Molybdenum(Mo) 15 13 ug/L
Total Selenium(Se) 7.0 7.1 ug/L
Total Silver(Ag) NO NO ug/L
Total Thallium ITO NO NO ug/L
TSS 146 mg/L
Oil and Grease NO NO mg/L
Mercury(Total) 28.7 1.02 ng/L
Phenol 0.01 mg/L
Cyanide NO NO mg/L
Sulfide NO ND mg/L
Total Organic Nitrogen Calculation 0.63 mg-N/L
Total Kjeldahl Nitrogen(Colorimetric) 0.83 1 mg-N/L
Field pH 7.4 Std.Units
Field Temperature 32 deg C
COD ) 20 NO mg/L
Chlorine,Total Residual 0.073 mg/L
�Less*Ziri(�)? ND=Non-Detectable
=No Data Available
Note:Data presented In this table represent a limited data set and are estimates for planning
purposes only.

Duke Energy Carolinas,I.I.C.
Rogers Energy Complex
NPQES PERMIT 0 NC0005080
Supplemental Information Package
Attachment E
Effluent Guidelines Rule Justification for Applicability Dates

J.E.Rogers Energy Complex(Cliffside Steam Station): Effluent Guidelines Rule
Justification for Applicability Dates
A. Introduction
Duke Energy (Duke) is working diligently to develop and refine an optimized schedule for the 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 the J.E.Rogers Energy Complex(REC),located in Belmont,North
Carolina.
REC consists of two coal fired generating units with a total summer generating capacity of 1,396 MW.Unit 5 has
a rated summer capacity of 552 MW and Unit 6 has a rated summer capacity of B44 MW. Fly ash and bottom
ash transport water (BATW) are generated by the operation of Unit 5 and sluiced to the ash pond treatment
system and subsequently discharged thru ouffall 002. Blowdown from the Unit 5 wet FGD is treated by the FGD
wastewater treatment system and discharged to the ash pond thru internal outfall 004. The FGD treatment
wastewater treatment system consists of chemical addition,followed by a clarifier and sand filters.
Unit 6 utilizes a wet FGD scrubber as well as a spray dry absorber. FGD blowdown from the wet FGD is used as
make-up water for the lime slurry used in the Unit 6 spray dry absorber. Any unused FGD blowdown is treated
along with the FGD blowdown from Unit 5 by the FGD wastewater treatment system then discharged thru
internal outfall 004.A mechanical drag system(submerged mechanical flight conveyor)is used to handle bottom
ash generated by the operation of Unit 6. Per EPA's definition,a mechanical drag system(MDS)is considered a
dry bottom ash system, thus, the system does not generate BATW.r Please refer to Attachment F for further
details on the ELG applicability of a MDS.
The ELG Rule sets a range of possible applicability dates for compliance with the new best available technology
(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 REC, 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
"A mechanical drag system collects bottom ash from the bottom of the boiler in a water-filled trough.The water bath in the
trough quenches the hot bottom ash as it falls from the boiler and seals the boiler gases.A drag chain operates in a continuous
loop to drag bottom ash from the water trough up an incline,which dewaters the bottom ash by gravity,draining the water back
to the trough as the bottom ash moves upward.The dewatered bottom ash is often conveyed to a nearby collection area,such
as a small bunker outside the boiler building,from which it is loaded onto trucks and either sold or transported to a landfill.The
MDS is considered a dry bottom ash handling system because the ash transport mechanism is mechanical removal by the drag
chain,not the water."80 Fed.Reg.at 67,692 col.3.

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.
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 for REC 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 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 REC Unit 5 to a dry
bottom ash handling system, Duke plans to install a MDS. Duke would like to request December 31,
2020 as the applicability date for the no discharge of BATW, assuming a permit effective date of
November 1,2016. Duke anticipates that equipment will be installed by December 31,2019 to comply
with the Noah 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
would like a 12 month window to optimize the system. This additional time is needed to account for
managing the installation and optimization of four remote mechanical drag systems (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 six month to account for potential permitting
delays.As discussed in Attachment F,a MDS does not generate BATW.Any discharges from the MDS
2

are classified as low volume waste under the ELG rule. The zero discharge limits, therefore, for BATW
are not applicable to Unit 6.
■ FGD wastewater:Additional treatment will need to be added to the FGD wastewater treatment system
to meet the BAT limits for FGD wastewater.At a minimum,we plan to evaluate enhancement of the
existing physical/chemical system augmented by a selenium reduction system. It has come to Duke's
attention the availability of biological treatment systems may be limited due to intellectual property rights
being claimed by GE,which would limit the vendor resources to supply the model technology.To
account for uncertainty in vendor resources and evaluate selenium reduction technologies other than
biological treatment, Duke would like to request December 31,2023 as the applicability date for the
BAT limits for FGD wastewater.
■ Fly Ash Transport Water: Fly ash generated by the operation of Unit 6 is handled dry. For Unit 5, dry fly
ash conversion is in process and anticipated to be completed by the end of 2017. Duke, therefore, 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
The entire bottom ash transport system for Unit 5 will need to be replaced to comply with the no discharge limit
of 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 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 MDS for Unit 5 to handle bottom ash dry. Once installed and optimized, the system
would not generate BATW. Any discharges from the system would be classified as low volume waste under the
ELG rule. See Attachment F for further details on regulating discharges from a MDS. Duke anticipates 50
months from the effective date of the permit will be needed to design, install and commission the MDS 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 in addition to the MDS at REC; therefore, additional time is needed compared to a
single installation to account for managing multiple projects simultaneously.
Mechanical Drag System (MDS)
Activit Duration Months
Design' 8
• Siting 2
• Engineering 4
Procurement 12
Potential Permitting Delays 6
Construction/Tie-in i4
Optimization &Operational Ex erience2 12
3

• Commissioning 2
• Start-Up 6
Total: 50
1)The design tasks has been initiated and Duke estimates an additional 6 months from the permit
effective date(assuming Nov.t,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 12 month window to obtain the necessary operating time at full load and account for
commissioning/optimizing multiple facilities simultaneously.
Assuming a permit effective date of November 1, 2016, Duke estimates the system can be installed and
operated to comply with the zero discharge limit of BATW on or before December 31,2020. To design,procure,
construct and optimize the MDS for REC Unit 5,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 6 months from the permit
effective 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 MDS is to develop a detailed water balance of the current BATW.
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,
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 MDS system and piping reroutes of non-
BATW can commence.
Siting
The components of the MDS will need to be sited appropriately to avoid station equipment and allow access for
collection and disposal of the bottom ash.
Permitting
Once the MDS is commissioned, the permitted discharge flows will change drastically. The amount of water
discharged could be reduced by as much as 85%. Duke, therefore, will need to design, and construct a new
treatment system for these low volume wastes. The size and technology of the treatment system will be
4

determined based on the water characterization study discussed above.Additionally,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 expected 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.
MDS 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 MDS will take approximately
14 months. In addition,the tie-in of the MDS to Unit 5 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 12 month window will be required to gain the necessary operational experience and fine-tune the
system.The 12 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 account for commissioning / optimizing occurring at multiple
facilities simultaneously.
C.New Wastewater Treatment System
5

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 enhance the existing physical/chemical treatment
system and install 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.
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."
6

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 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 86 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 22
•
Technology Evaluation 12
•
Siting 4
•
Engineering 6
Procurement' 27
Potential Permitting Delays 6
ConstructioNTie-in' 16
Start-up&0 timization2 15
• Commissioning 6
• Start-Up 6
Total: 86
1)Duke is allocating a 27 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
o eratin conditions from full load to partial load to periods of no load.
Assuming a permit effective date of November 1 2016, 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 REC,the following steps must be taken:
Design&Engineering
7

As with the MDS,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 22 months to complete the design and engineering phase of the project.
Siting
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 REC. 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(USAGE)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 REC.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 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 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 though the permitting task will be initiated during the design and engineering phase, it is expected 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;
8

— 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 27 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 15 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-ug
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 stales:
"From an environmental protectiontcoordination 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
9

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 REC, 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.
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 REC 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 is 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 REC 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
10
I

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 Roger'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 Roger varies throughout the year.Typically one unit is 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 authority should consider grid reliability in setting applicability dales:
"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 BATW 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.
l'1

Duke Energy Carolinas,I.I.C.
Rogers Energy Complex
NPDES PERMIT#NCOOMOSO
Supplemental Information Package
Attachment F
Position Paper Mechanical Drag System

Effluent Limitations Guidelines and Standards for the steam Electric Power
Generating Point Source Cate o •Final Rule
Position Paper:Mechanical Drag System(aka Submersed Flisht Conveyor)
Revisions to the Steam Electric Effluent Limitations Guidelines (ELG) were published in the Federal
Register on November 3, 2015 with an effective date of January 4, 2016. The revised ELG standard
established a no discharge limit as best available technology (BAT) for bottom ash transport water,
except when bottom ash transport water is used in the flue gas desulfurization(FGD)scrubber'.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, whereas a remote mechanical drag system was identified as
the technology basis for a closed-loop system2. The preamble to the rule defines a mechanical drag
system as:
"A mechanical drag system collects bottom ash from the bottom of the boiler in a water-
filled trough. The water bath in the trough quenches the hot bottom ash as it falls from
the boiler and seals the boiler gases. A drag chain operates in a continuous loop to drag
bottom ash from the water trough up an incline, which dewaters the bottom ash by
gravity, draining the water back to the trough as the bottom ash moves upward. The
dewatered bottom ash is often conveyed to a nearby collection area, such as a small
bunker outside the boiler building,from which it is loaded onto trucks and either sold or
transported to a landfill. The MDS is considered a dry bottom ash handling system
because the ash transport mechanism is mechanical removal by the drag chain, not the
water."a
The rule also defines a dry bottom ash handling system as "a system that does not use water as the
transport medium to convey bottom ash away from the boiler. It includes systems that collect and
convey the ash without any use of water, as well as systems in which bottom ash is quenched in a water
bath and then mechanically or pneumatically conveyed away from the boiler.i4 Therefore, based on the
above definitions, a mechanical drag system clearly meets the technology requirements for the BAT
limitations for bottom ash transport water.
Throughout the Technical Development Document (TDD), EPA acknowledges that a MDS is not a
completely dry system, but reiterates that water is not used to transport the ash and thus it is
considered,for the purpose of the TDD and the ELG rule,to be a "dry" bottom ash systems EPA further
acknowledges that a MDS does generate some wastewater (i.e., residual water that collects in the
140 C.F.R.§423.13(k)(1)(i)
'80 Fed.Reg.at 67,852 cot 3
3 80 Fed.Reg.at 67,892 cal.3
°80 Fed.Reg.at 67,892 cal.1
5 Technical Development Document for the Effluent Limitations Guidelines and Standards for the Steam Electric
Power Generating Point Source Category(TDD)p.3-21 and 4-24.

storage area as the bottom ash continues to dewater), but EPA states this wastewater is not considered
bottom ash transport water because the transport mechanism is the drag chain, not the water. EPA,
therefore,did not include operation as a closed-loop system in the MDS design for the BAT technology;
thus,eliminating the need for a heat exchanger.fi
Based on the facts presented in the preamble to the rule,the TDD and presented above,a MDS does not
generate bottom ash transport water; therefore, the BAT limitations of zero discharge of bottom ash
transport water at are not applicable.Also,as stated above and in the TDD, EPA recognizes water is used
and wastewater is generated by a MDS, but this wastewater is not bottom ash transport water.
Therefore,by default any wastewater generated from the MDS should be classified as low volume waste
under the final ELG rule. This is consistent with the definition of low volume waste, which states, "The
term low volume waste sources means, taken collectively as if from one source, wastewater from all
sources except those for which specific limitations or standards are otherwise established in this part."'
This conclusion is further supported by EPA's description of a MDS within the TDD, where it is stated
"Any water leaving with the bottom ash does not fall under the definition of "bottom ash transport
water," but rather, is a low volume waste."B in addition, EPA confirms that water generated from an
MDS is not transport water in the Response to Comments:
"Water generated from the mechanical drag system (MDS)is not subject to the bottom
ash transport water limitations and standards. In a mechanical drag system, the
mechanical scraper is used to convey the ash;therefore, these systems do not use water
as the medium of transport and do not constitute a transport water system. Therefore,
water generated from the mechanical drag system is not subject to the final rule
requirements for bottom ash transport water. As such, the water draining from the
bottom ash is also not transport water. However, in a system that does generate
bottom ash transport water(e.g., remote MDS), the water that drains from the bottom
ash in the dewatering bunker is considered bottom ash transport water and is subject to
the bottom ash transport water limitations and standards"!
In the proposed rule, EPA clearly stated quench water in an MDS is not transport water, but is a low
volume waste:
"Alternatively,some furnaces are fitted with mechanical drag systems where the bottom
ash drops into a water-filled trough, but the ash is removed using a submerged
mechanical drag conveyor that drags the bottom ash out of the furnace. At the end of
the trough, the drag chain reaches an incline, which dewaters the bottom ash by gravity,
draining the water back to the trough as the ash moves up the conveyor. The bottom ash
6 TDD,p.7-41
40 C.F.R.§423.11(b)
s TDD,p.7-41
9 Response to Comments,p.4-351.

is often dumped into a nearby bunker for temporary storage. As the bottom ash
continues dewatering in the nearby bunker, water that drains from the system may be
discharged; however, EPA does not consider this water from the bunker to be bottom
ash transport water because the mechanical conveyor, and not the water, is the
transport mechanism that moves the ash away from the boiler. Instead, the wastewater
draining from the bunker would be low volume wastes".10
Therefore, based on statements in the preamble of the rule, the TDD and Response to Comment
document, discharges from the MDS should be classified a low volume wastewater under the ELG rule
and subject to limits for total suspended solids(TSS)and oil and grease (O&G).
10 78 Fed. Reg.at 34,449.

Duke Energy Carolinas,I.I.C.
Rogers Energy complex
NPOES PERMIT N NC0005088
Supplemental Information Package
Attachment G
Alternate Schedule Request §316(b) of the Clean Water Act

Alternate Schedule Request§316(b)of the Clean Water Act
Duke Energy Carolinas, LLC
Rogers Energy Complex
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. Based on our initial review of the regulations,the
following reports, unless waived,are required to be submitted for Cliffside Steam Station to comply with
the 316(b)regulation:
§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
As allowed under §125.95(0)(2), Duke Energy would like to request an alternate schedule for the
submittals listed above. Information requested in §122.21(r)(2), (3), and (5)were completed under the
remanded rule; however, the operations at Cliffside Steam Station have substantially changed since the
remanded rule. Units 1—4 have retired and Unit 6 has commenced operation. In addition, information
requested in §122.21(x)(4) is substantially different from the remanded rule. Information requested in
§122.21(r)(6)—r(8)are new provisions and these submittals must be developed.
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'. Given the current effective permit for Cliffside Steam Station
expires on July 31, 2015, Duke Energy would like to request the above information for Cliffside Steam
Station to be required with the subsequent permit renewal application.
' Refer to§125.95(a)(1)and(2)

Duke Energy Carolinas,L.L.C.
Rogers Energy Complex
NPDES PERMIT If NCODOSG i8
Supplemental information Package
Attachment H
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