NC0003417_Comments_20180613

DUKE H. F. Lee Energy Complex
ENERGYDuke Energy Progress
1199 Black Jack Church Road
Goldsboro, NC 27530
June 13, 2018
RECEIVED/DENRIDWR
Mr. Jeffrey Poupart, Section Chief JUN 2 2 2018
NC Division of Water Resources
1617 Mail Service Center Water Resources
Raleigh, NC 27699-1617 Permitting Section
Subject: HF Lee Energy Complex
Amendment to existing NPDES permit renewal application
NC0003417
Wayne County
Dear Mr. Poupart,
Duke Energy Progress, LLC (Duke Energy) submits this letter to amend the pending NPDES
permit application under consideration by the Division. The amendment is to revise several
outdated descriptions in the permit application narrative. This submittal is solely administrative
and for information only for use in the development of the permit. Duke Energy is not making
any additional requests for permit modification with this submittal.
An updated narrative is attached. If you have any questions regarding this letter,please contact
Mr. Steve Cahoon at(919) 546-7457 or [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.
Respectfully Submitted,
)1 PI mDomeo
Gary Davis, Operations Superintendent delegated authority for Jeff Hines, Manager, Lee Plant
Cc. David May-DWR Washington Regional Office
Steve Cahoon—NCRH 15th floor
Mike Graham—HF Lee
Shannon Langley—NCRH 15th floor

Duke Energy Progress Inc. H.F. Lee Energy Complex
NPDES Permit Number NC0003417
Attachment 4. Description of Operations Contributing to Wastewaters at Outfall 001, Outfall
002 and Outfall 003
The H.F Lee Energy Complex has retired and demolished three coal-fired generating units and four
simple cycle combustion turbines. Commercial operation of the site's newly constructed 3 X 1
combined cycle electric generation block began on December 31, 2012. The site now consists of five
(5) simple cycle combustion turbines and the combined cycle unit. Total electric generation capacity
for the site is over 1800 Megawatts.
The site will continue to utilize the existing 545 acre off-stream closed-cycle cooling pond for
condenser cooling and process water. Water is withdrawn from the Neuse River, as required, to make
up evaporative, seepage, and discharge losses from the cooling pond. Makeup pumping rates are
highly variable depending upon natural weather conditions, generation load and plant operations,
quantity of water available in the river, and pond water levels. The maximum normal operating level
of the cooling pond is maintained at a safe level below the crest of the spillway gates. Discharges from
the cooling pond are rarely made, usually only during an extremely heavy rainfall event or a hurricane.
The cooling pond last discharged on October 9, 2016 during Hurricane Matthew, prior to Hurricane
Matthew the last cooling pond discharge was in 1998. Chemical constituents contained in the cooling
pond discharge are, for the most part, representative of the naturally-occurring chemical quality and
quantity of the intake water.
Upon retirement of the coal fired units, waste streams from processes which historically went to the
ash pond or the cooling pond will either no longer be generated or will be redirected to new outfall 003
to the Neuse River. More detail on these specific wastestreams is provided below.
In addition to the permitted outfalls, backwash from intake screening devices may be discharged into
the Neuse River bypass canal associated with the Neuse River pursuant to NCAC 15A 2H .0106 (f)
(2).
The combined cycle plant utilizes water from the 545 acre off-stream cooling pond as its source for
fire water. Infrequently, flushing and testing of the fire system may result in releases of the fire water.
The following is a description of wastewater streams that will be reflective of the new H.F Lee Energy
Complex:
Contributing Flows into the Ash Pond (NPDES outfall 001)
The coal plant has been retired and no routine flows associated with coal fired generation are sent to
the ash pond. Wastestreams from closure activities associated with the coal fired unit may still be sent
to the ash pond until closure is complete. Duke Energy Progress, Inc. wishes to maintain outfall 001 as
an active outfall to ensure permitted coverage of any incidental discharges which may occur associated
with heavy rainfall events and to facilitate any needed groundwater remediation and dewatering for
future closure of the wastewater treatment. Wastestreams that have been historically sent to the ash
pond include:
Fly ash and bottom ash from all three coal fired units were hydraulically conveyed by ash sluice
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Duke Energy Progress Inc. H.F. Lee Energy Complex
NPDES Permit Number NC0003417
pipelines to the Lee Plant ash pond. (Ceased)
Precipitator and Air Pre-heater Wash Water
Water from washing the interior of the precipitators and air heaters is typically routed to the ash pond
via the ash transport system but could be routed directly or indirectly to the cooling pond. The
wastewater from the Rotamix treatment system added to Unit 3 for NOx removal is also routed to the
ash pond. (Ceased)
Filter Plant Wastewater
Blowdown and filter backwash wastewater generated in the filter plant is recirculated back to the
clarifier.
Wayne County Combustion Turbine Site Wastewaters
The primary containments around the accessory module, liquid fuel, and atomizing air modules and the
wash water drain empty into collection tanks. Once there is a quantity of liquid collected in the tanks,
the wastewater is removed by pumper truck and transported offsite. The wash water drain tanks
collect the water and detergent used to clean the CT compressors. (To be redirected to outfall 003,
Outfall 002 or disposed of offsite after ash pond closure)
Miscellaneous Wastes
Cooling tower basin sludge, circulating water tunnel sediment, and boiler vacuuming sediments are
sent to the ash pond. Other residuals from the low volume wastes retention basin and the coal pile
runoff retention basin and other miscellaneous low volume wastes from plant processes are also
transported to the ash pond.(Ceased). Storm water from the ash line trench flows into the ash pond.
There may be seepage in the vicinity of the ash pond. Some seeps may be seasonal.
Bulk water decanting/Interstitial Dewatering
Bulk and interstitial ash basin water will be decanted/dewatered from the 1982 ash pond through
Outfall 001. Additional wastewater equipment will be brought onsite to assist in the bulk and/or
interstitial decanting/dewatering. The additional wastewater treatment consists of:
• Ballasted flocculation;
• Catalytic oxidation media filters;
• Coagulant, polymer, and additive feed systems;
• Ion exchange resin;
• Reverse osmosis system;
• Filter press trailers and sludge holding tanks
Low volume wastes from the wastewater treatment system(WTS)as well as stormwater from the
WTS pad area are recycled back to the ash pond. Sludge is removed from the system. The WTS will
only discharge through Outfall 001.
Groundwater Extraction Well System
Duke Energy anticipates the future need of an extraction well system to provide accelerated
arnnndwater remediation. The gronndwater will he treated prior to discharge through outfall 001.
Treatment of the discharge may be provided by introducing the groundwater as a waste stream to the
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Duke Energy Progress Inc. H.F. Lee Energy Complex
NPDES Permit Number NC0003417
ash ponds (for treatment through the WTS), direct treatment through the WTS, or direct treatment
through a dedicated groundwater treatment system.
Contributing Flows into the Cooling Pond (Closed Cycle) (NPDES outfall 002)
Re-circulated Condenser Cooling Water
This flow will provide condenser cooling water for the 3x1 combined cycle generation units. The total
flow is re-circulated into the 545 acre pond from the condensers, routed through the pond by baffle
dikes to achieve maximum surface cooling efficiency before reaching the condenser cooling water
intake to be again introduced to the condensers for cooling. Cooling of the recirculated water in the
pond is achieved primarily by evaporation from the pond surface, which is estimated to consume
approximately 3-5 MGD above natural evaporation rates during times the units are in full operation.
Biological fouling control agents are used on heat exchanger surfaces. Some flows from stormwater
drains on the Lee plant site will still be directed to the cooling pond.
Sewage Treatment System(limited use)
Y
Domestic waste is treated in a septic tank and sand filter bed system. Flow from the system is
dependent upon fluctuating demand due to variations in the number of personnel on site. Residuals are
disposed of off-site by a licensed contract disposal firm. The sand in the system is periodically changed
to ensure system effectiveness is maintained. The spent sand is disinfected and disposed of in a landfill
(Ceased).
Coal Pile Runoff
Until the coal pile is completely removed, runoff will still be directed to the cooling pond. The coal
pile area is surrounded by a drainage ditch that is routed to a clay-bottomed, asphalt and concrete-sided
settling basin. The settling basin is sized so as to adequately store runoff and allow suspended solids to
settle before the supernatant is discharged by overflow to the cooling pond. During routine
maintenance of the basin, any solids removed will be disposed of in the active ash pond. (Ceased)
Other
During routine maintenance, the water treatment plant clarifier may be drained to the cooling pond to
allow for inspection of the clarifier. This activity typically occurs annually but may occur more frequently.
Additionally, should the filter press not be operational, clarifier solids may temporarily be directed to the
wastewater cooling pond for a short duration until the filter press can be repaired. This is expected to be
infrequent and will not be a routine operating mode.
Wastewater associated with the cleaning the plant process reverse osmosis process unit will be taken
offsite or directed to the cooling pond. If directed to the cooling pond an antifoam chemical may be added
to the wastewater.
A blowdown stream from the combined cycle Heat Recovery Steam Generator is directed to the cooling
pond.
The HF Lee Plant has constructed piping to allow for all of the flows listed below which contribute to
Outfall 003 to be discharged into the cooling pond. Including Wayne County Combustion Turbine Site
Wastewaters,which are described below.
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Duke Energy Progress Inc. H . Lee Energy Complex
NPDES Permit Number NC0003417
Filter Plant Wastewater
Existing water treatment plant clarifier blow down and filter backwash wastewater generated in the
filter plant was previously discharged into the ash sluice transport system and to the ash pond. Filter
backwash and clarifier alum solids will be treated via a gravity thickener and filter press. Filtrate from
the filter press was previously commingled with other waste streams and directed to outfall 003. This
flow has been rerouted and is now back to the water treatment plant clarifier. Solids from the filter
press will be disposed of at an offsite location, or on rare occasion in the cooling pond.
Existing Wayne County Combustion Turbine Site Wastewaters
Water from the cooling pond passes through a clarifier,dual media sand filters and then through a five-
micron cartridge pre-filter before entering either of two reverse osmosis (RO) units. The two RO units
may be operated in parallel or series depending on operational needs. The treated water is stored in a
tank until needed. Reject wastewater from the reverse osmosis process is sent to a sump where it will
be routed to either the cooling pond(outfall 002)or outfall 003.
In addition to the RO reject wastewater, excess evaporative cooling water, process drains, and waters
from the oil water separator will be routed to the cooling pond(outfall 002) or routed to outfall 003.
Historically, the primary containments around the accessory module, liquid fuel, and atomizing air
modules empty into collection tanks. Once there is a quantity of liquid collected in the tanks, the
wastewater is removed by pumper truck and transported offsite. The wash water drain tank that
collects the water and detergent used to clean the CT compressors. (To be redirected to Outfall 003,
Outfall 002, or disposed of offsite after the ash pond closure).
An oil water separator treats storm water from the containment areas around the facility's fuel oil
storage tanks, the fuel forwarding pumps, and the fuel oil unloading area. Water from the oil water
separator will be conveyed to the new collection sump and routed to outfall 003, or the cooling pond
(outfall 002). Storm water collection containment areas around transformers and substations are
examined for the presence of any oily substance; if oily substances are not present in the water, the
water is drained to the ground. If oily substances are present nothing will be drained from the
containments until that substance is properly removed.
Outfall 003 will also contain a blowdown stream from the wet surface air cooler (WSAC).
Wastewaters from routine cleaning, fuel oil/water condensate, false start materials, equipment drains
containing potential oil, and compressor wash water may be routed to outfall 003. Any of these waters
with a potential for containing oil are routed through the oil water separator before being sent to outfall
003. Incidental leaks associated with the routine operation of the combustion turbine heat recovery
steam generator may occur and get to the ground surface. Other infrequent draining and cleaning of
various process units during operation and maintenance activities may generate wastewater that will be
routed to outfall 003. These wastewaters may also be routed to the cooling pond(outfall 002).
Contributing flows to Outfall 003
Filter Plant Wastewater
Existing water treatment plant clarifier blow down and filter backwash wastewater generated in the
titter plant was previously uisctlargeu into uiC aSu Stoke lial!spull system Sulu to Cm 4511 pond. i'iiLCI
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Duke Energy Progress Inc. H . Lee Energy Complex
NPDES Permit Number NC0003417
backwash and clarifier alum solids will be treated via a gravity thickener and filter press. Filtrate from
the filter press was previously commingled with other waste streams and directed to outfall 003. This
flow has been rerouted and is now back to the water treatment plant clarifier. Solids from the filter
press will be disposed of at an offsite location, or on rare occasion in the cooling pond.
Existing Wayne County Combustion Turbine Site Wastewaters
Water from the cooling pond passes through a clarifier, dual media sand filters and then through a five-
micron cartridge pre-filter before entering either of two reverse osmosis (RO) units. The two RO units
may be operated in parallel or series depending on operational needs. The treated water is stored in a
tank until needed. Reject wastewater from the reverse osmosis process is sent to a sump where it will
be routed to either the cooling pond(outfall 002) or outfall 003.
In addition to the RO reject wastewater, excess evaporative cooling water, process drains, and waters
from the oil water separator will be routed to the cooling pond(outfall 002) or routed to outfall 003.
Historically, the primary containments around the accessory module, liquid fuel, and atomizing air
modules empty into collection tanks. Once there is a quantity of liquid collected in the tanks, the
wastewater is removed by pumper truck and transported offsite. There is also a drain tank that collects
the water and detergent used to clean the CT compressors. All of these wastewaters will be either
pumped and hauled offsite or redirected to the cooling pond (outfall 002) or outfall 003 after the ash
pond is no longer used.
An oil water separator treats storm water from the containment areas around the facility's fuel oil
storage tanks, the fuel forwarding pumps, and the fuel oil unloading area. Water from the oil water
separator will be conveyed to the new collection sump and routed to outfall 003, or the cooling pond
(outfall 002). Storm water collection containment areas around transformers and substations are
examined for the presence of any oily substance; if oily substances are not present in the water, the
water is drained to theground. If oilysubstances arepresent nothingwill be drained from the
containments until that substance is properly removed.
Outfall 003 will also contain a blowdown stream from the wet surface air cooler (WSAC).
Wastewaters from routine cleaning, fuel oil/water condensate, false start materials, equipment drains
containing potential oil, and compressor wash water may be routed to outfall 003. Any of these waters
with a potential for containing oil are routed through the oil water separator before being sent to outfall
003. Incidental leaks associated with the routine operation of the combustion turbine heat recovery
steam generator may occur and get to the ground surface. Other infrequent draining and cleaning of
various process units during operation and maintenance activities may generate wastewater that will be
routed to outfall 003. These wastewaters may also be routed to the cooling pond(outfall 002).
Beneficiation Plant(new outfall)
A planned coal ash beneficiation system is being designed for the site. Coal ash beneficiation is a
process where ash is excavated from a basin and in essence re-burned to remove carbon to make the
material suitable for reuse as a product in cement. The HF Lee Energy Complex is one of the three
sites chosen by Duke Energy to comply with the mandate for beneficiation in the 2016 amendments to
the Coal Ash Management Act.
n_ _ 1,_7 ._.-1. .:11 1.. til .., ..F♦1... 1.....:.... n.. n.l 1nnr1 n,I♦ nrnn f .,inn in tl,n
beneficiation unit. Small amounts of truck wash water and waste water for dust suppression will he
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Duke Energy Progress Inc. H.F. Lee Energy Complex
NPDES Permit Number NC0003417
potential streams originating from the beneficiation facility. Any stormwater contacting ash would be
collected in a sump, leading to a basin with a capacity to hold potential 25-year storm event. This basin
discharges to an oil-water separator, then routed to one of the two proposed flow paths described
below.These flows will typically be less than 0.005 MGD. Untreated wastewater analytical results are
provided in Table 1. from an existing beneficiation facility in another State. This site is not owned by
Duke Energy but is operated by the same company that will be operating the Buck and Cape Fear
beneficiation system. Flows from the existing site where this data was obtained flow to the sites ash
basin for treatment. Designs for the HF Lee beneficiation facility are in progress,however the flow
path for any waste water generated by the facility would be a new outfall to the Neuse River. Duke
Energy requests that limits and authorizations associated with a new outfall for the beneficiation plant
be included in the renewed permit to avoid having to re-open the permit in the near future.
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