NC0003425_Application for Permit Modification_20090519

Progress Energy
gY
File: 12520
Mr. Gil Vinzani
Supervisor, Eastern NPDES Unit
1617 Mail Service Center
Raleigh, NC 27606
Dear Mr. Vinzani:
MAY 2 2 2009
DENR - WATER OUALITY
POINT SOURCE BRANCH
NPDES permit application modification
Minor permit modification request
Roxboro Steam Electric Plant
Permit Number: NC0003425
Person County
This correspondence is to follow up on earlier conversations and emails between you and staff of
Progress Energy regarding the use of a portable Reverse Osmosis (R.O.) system at Roxboro
Steam Electric Plant. The Roxboro Steam Electric plant intends to install a portable R.O. system
to aid in conditioning of Boiler make up water. The portable RO would be used in conjunction
with the existing demineralization equipment currently on site that conditions intake water from
Hyco Lake for use in plant processes. The system is not proposed to treat wastewater and would
be leased for temporary use with an option to purchase for permanent use.
The existing filtering, softening and demineralization equipment along with the waste stream
associated with this equipment is described in our NPDES permit in Attachment 4, under "Low
volume waste". Since the R.O. system waste stream is by definition "low volume waste" we
request a minor modification of our NPDES permit to include the portable R.O. system in the
description under "low volume waste." Enclosed are updated copies of Attachment 4 for your
files of our NPDES application. The R.O system will have a reject stream that will go to the ash
pond with other low volume waste where it will be treated by sedimentation, oxidation,
neutralization, equalization, and adsorption.
Also enclosed is an update to the chemicals list in Attachment 5 to identify the chemicals used in
the R.O. treatment process. These chemicals used in association with the R.O. system are
primarily acids and detergents that will be used every one to three months (for R.O. cleaning), an
anti -sealant and filter aid used in small quantity continuously.
Progress Energy Carolinas, Inc
Roxboro Steam Plant
1700 Dunnaway Road
Semora„ NC 27343

In addition, we are planning to add Phosphate (Nalco BT 3000) for additional treatment of Boiler
water and Magnesium Hydroxide sprayed onto coal for Slagging mitigation and SO3 mitigation.
A chemical worksheet (DWQ form 10 1) has been prepared for all these constituents and has
been forwarded to the Aquatic Toxicology Unit of DWQ. All chemicals "pass" the aquatic
toxicity evaluation.
It is our understanding from conversations with you that this will be a minor modification of our
permit that will update the description of the term "low volume waste" in our "Supplement to
Permit Cover Sheet". As has been previously relayed to you, we wish to add the use of the RO
system as soon as possible to aid with plant operations. If you have any questions, please feel
free to contact Mr. Shannon Langley at [phone] or Shannon. langle cr,pgnmail.com.
Respectfully,
Harry Sideris, Plant Manager
Roxboro Steam Electric Plant
HS/sl
Enclosures
Cc: Robert Howard
Shannon Langley -OPEB4

Attachment 4
Form 2C - Item II -B Flows, Sources of Pollution, and Treatment Technologies
The Roxboro Steam Electric Plant, located in Person County, North Carolina, consists of four
coal fired generating units with net dependable capacities of 385, 670, 707, and 700 MW for
units 1, 2, 3, and 4 respectively. All plant waste streams are routed directly or indirectly to
the Hyco Reservoir. Chemical constituents contained in these discharges will, in part, be
representative of the naturally occurring chemical quality and quantity of the intake water and
will also have chemical constituents of such quality associated with similar discharges for
fossil generating facilities of this size, type, and in this geographical location. Either all or
part of the elements in the Periodic Table, either singularly or in any combination, may from
time to time be contained in the discharges. Each component of the discharges is described
below.
Outfall 003 - Discharge Canal
At the point that the discharge canal enters the Hyco Reservoir, it contains the flows from
several waste streams, including once -through cooling water, stormwater runoff, and the
effluent from the ash pond, which in turn receives and treats combined flows from the ash
transport system, the low volume waste system, the dry fly ash handling system, cooling
tower blowdown, stormwater runoff, drainage from the ash landfill and from occasional
wastewater piping leakage.
Once -Through Cooling Water
Condenser Cooling Water (CCW) for Units 1, 2, and 3 is drawn from the Hyco
Reservoir via an intake canal and discharges to the Hyco Reservoir via a discharge
canal. Flows for Units 1, 2, and 3 are 249 MGD, 342 MGD, and 505 MGD
respectively. Cooling is accomplished by evaporation from the surface of Hyco
Reservoir and mixing and convection with the reservoir waters.
During the summer months, Unit 3 CCW is routed through mechanical draft cooling
towers where most of the waste heat is removed by evaporation before the water is
discharged to the reservoir via the discharge canal along with the CCW of Units 1 and
1

water, the flow of which is combined with the CCW prior to introduction into the
discharge canal.
Ash Pond Discharge
The ash pond receives ash transport water, low volume wastes, runoff from the ash
landfill, dry fly ash handling system wash water, blowdown from Unit 4 cooling tower,
coal mill refects and pyrites, and sewage treatment plant effluent. The pond provides
treatment by sedimentation, oxidation, neutralization, equalization, and adsorption
Ash Transport Water
Water for sluicing ash to the ash pond is withdrawn from the CCW system as
needed The plant will primarily supply ash sluice water from Unit 2 However,
the facility will continue to maintain the ability to operate the unit 4 ash sluice
pumps The Unit 4 ash sluice pumps are and will continue to be utilized for the
following i) during maintenance draining of the cooling tower, ii) back-up supply
for the fire suppressant system, and iii) ash sluicing pumps during operational
events which require additional pumping Normally, only bottom ash is
conveyed to the ash pond by sluicing. Fly ash is handled dry by a pneumatic
system and is landfilled on site or sold If the dry fly ash handling system is out
of service during plant operating periods, fly ash will be sent to the ash pond via
the ash sluicing systems until the dry system is restored. Such occurrences are
expected to be infrequent and brief.
Silo Wash Water
Ash silo wash water runoff and dust suppressant spray runoff from the dry fly
ash handling system are routed to the ash pond
Low Volume Wastes
Boiler make-up water is withdrawn from the CCW system and filtered, softened,
and demineralizered for treatment. This process may include treatment via a
reverse osmosis system. Boiler water is treated with ammonia, hydrazine
phosphate, and occasionally sodium hydroxide. Boiler blowdown is sent to the
ash pond via the low volume wastes collection system (LVWS); these are
special drains in the plant that flow by gravity to collection sumps and are
pumped to the ash pond. Ethylene glycol is used for freeze protection of some
2

equipment and may be discharged to the LVWS, as is some molybdate waste
from the closed cooling water system, during periods of maintenance. The
plant's demineralizers are regenerated using sulfuric acid and sodium
hydroxide. When this equipment is rinsed, small amounts of these chemicals
are discharged to the low volume system via the neutralization basin. The
plant's Reverse Osmosis system produces a reject waste stream of
approximately 250 gpm. Essentially all plant equipment, floor drains, water
treatment filter backwashes, clarifier and sedimentation basin sludge, and ash
hopper seal water overflow also discharge to the LVWS. In addition, a back-up
%r domestic sewage system can discharge to the LVWS. The back-up system
consists of a septic tank with a subsurface sand filter and a chlorine dosing
,_( ID chamber The back-up system can be used if the facility's extended aeration
treatment system is temporarily out of service
Cooling Tower Blowdown
g
Unit 4 is the only unit that produces cooling tower blowdown. A blowdown
stream is used to maintain concentrations of total dissolved solids in the cooling
tower to within proper operating limits. Make-up to the Unit 4 cooling tower is
from the Heated Water Discharge Canal
Domestic Sewage
Domestic sewage is treated by an extended aeration treatment plant consisting
of a screen, comminutor, surge tank, aeration tank, clarifier, chlorine contact
chamber, and a sludge holding tank
Coal Pile Runoff
The solids settling basin, which contains a portion of the wastewater runoff from
the coal pile and other coal handling areas of the plant, is routed to the ash
pond.
Ash Landfill Drainage
Water for sluicing a minimum amount of bottom ash to the ash landfill is
withdrawn from the ash transport system as needed. The bottom ash is used to
enhance the subsurface drainage of the landfill.
3

withdrawn from the ash transport system as needed. The bottom ash is used
to enhance the subsurface drainage of the landfill.
Air Preheater Cleaning (Low Volume Waste)
The air preheater will be water washed once per year or more frequently as
needed. The wastewater from this activity will be discharged to the ash pond.
Chemical Metal Cleaning Wastes
The boilers are chemically cleaned approximately every five -to -eight years as
required using Tetraammonia ethylene diamine tetraaccetic acid (EDTA)
solution or citric acid. This cleaning solution and its rinses are stored on site for
disposal by evaporation in an operating unit's furnace. Should evaporation not
be used, the wastewater can be treated by neutralization and precipitation prior
to being conveyed to the ash pond Alternatively, the wastewater can be
disposed by other acceptable disposal methods. Cleaning of other heat
exchanger surfaces may produce 5,000-10,000 gallons of wastewater
approximately every three -to -five years.
Stormwater Runoff
The stormwater runoff, which flows into the ash pond includes runoff from the
plant drainage area, landfill runoff (including silo area drainage), and the
drainage area from the ash pond (including roadways)
Flue Gas Desulfurization (FGD) System Blowdown Emergency
Overflow/Pipeline Drain
Emergency overflow from the FGD System blowdown will discharge to the ash
pond. This is expected to occur only in the event of extreme rainfall. If the
FGD System blowdown pipeline requires emergency draining, the contents of
the pipeline will be drained to a sump that is pumped to the ash pond.
Stormwater Runoff
The stormwater, which flows into the discharge canal includes runoff from the plant
drainage area, the drainage area from the dry flyash handling system (including
4

roadways), Unit 4 cooling tower drainage area, the fuel oil storage containment area,
the switchyard drainage area, the anhydrous ammonia tank farm, and the gypsum
storage pile area
Flue Gas Desulfurization Blowdown (Low Volume Waste)
The Flue Gas Desulfurization (FGD) system directs flue gas into an absorber where
limestone (calcium carbonate) slurry is sprayed. Sulfur dioxide in the flue gas reacts
with the limestone slurry to produce calcium sulfate (gypsum). The system reclaims
any unreacted limestone slurry to be reused in the absorber. A small blowdown
stream is used to maintain the chloride concentration in the reaction tank. The
blowdown stream will be discharged to a gypsum settling pond where suspended
solids will be reduced prior to entering a bioreactor The bioreactor utilizes microbes
to reduce soluble contaminants to insoluble forms that then precipitate from solution.
The treated wastewater will enter the ash pond discharge canal prior to outfall 002
Outfall 006 — Coal Pile Runoff
Wastewater runoff from the coal pile, limestone pile, gypsum pile, truck wheel wash and
other coal handling areas of the plant is routed to a retention pond for treatment by
neutralization, sedimentation, and equalization. The pond is designed to store in excess of
the 10-year/24-hour storm event Releases are controlled by a standpipe and skimmer
discharge structure. Included in the solids settling basin discharge beginning in January
2009 will be a truck wheel wash, which is necessary to help minimize offsite tracking of
gypsum and limestone onto state roads once the scrubber is online. Approximately 0.006
MGD of wheel wash water will be sent via gravity drain to the solids settling basin. Solids
from the wheel wash will accumulate in a separate settling basin to be removed by front end
loaders and sent to the landfill only the water will be going to the coal pile runoff pond via the
gravity drains.
5

Attachment 5
Form 2C - Item VI Potential Discharges Not Covered By Analysis
Chemical
Quantity
(used per year)
Frequency
Purpose
Anhydrous Ammonia
14,000 gal/wk
per unit
As required
(Seasonal)
Flue Gas Conditioning
Nalco 8338
385 gallons
As required
Corrosion Inhibitor
Nalclear 8173
(flocculant)
250 lbs
As required
Water Treatment
H-130 (Microbiocide)
2300 gallons
As required
Unit 4 Cooling Tower
Algae Control
Nalco 71 D5 Plus
(Antifoam Agent)
630 gallons
As required
Unit 4 Cooling Tower
Foam Control
Nalco 7396
(Polyphosphate)
110 gallons
Twice per day
Corrosion Inhibitor
Potable Water
Ice Free Conveyor
(Propylene glycol)
750 gallons
2100 lbs
As required
Conveyer Belt Freeze
Protection
Aluminum Sulfate
4000 gallons
As required
Water Treatment
Sodium Chloride
100,000 lbs
As required
Softener Regeneration
Sulfuric Acid
13,000 gallons
Twice per week
Demineralizer
Regeneration
Sodium Hydroxide
15,000 gallons
Twice per week
Demineralizer
Regeneration
Ethylene Glycol
6,000 gallons
As required
Freeze Protection Hot
Water Coil System
Lime
2,500 lbs
As required
Wastewater pH Control
Hydrazine
1,760 gallons
As required
Feedwater Oxygen
Ammonia Hydroxide
1,760 gallons
As required
Boiler Water pH Control
Chemical
Quantity
(used per year)
Frequency
Purpose
Sodium Hydroxide
200 lbs
As required
Boiler Water pH Control
Rev 10/06

Sodium Hypochlorite
400 gallons
Twice per day
Potable Water
Treatment
BT-21OW
40,000 lbs
As required
Dust Suppressant
(estimated)
Coaltrol 35
40,000 lbs
As required
Dust Suppressant
Sodium Bicarbonate
20,000 lbs
As required
Wastewater pH Control
Caustic Soda (20%)
110 gallons
Twice per day
Potable Water pH
Control
Molten Sulfur
525,000 lbs
As required
Flue Gas Conditioning
Sanuril Tablets
135 lbs
As required
Biocide for Sewage
(Calcium Hypochlorite)
Treatment
Nalclean
200 lbs
As required
Softened Water System
Sodium Carbonate
8,000 lbs
As required
Air preheater wash
water neutralization
EDTA
69,000 lbs/boiler
As required
Boiler Cleaning
A300
50 gallons/boiler
As required
Boiler Cleaning
(Chelating Agent)
M045 Silicone
15 gallons/boiler
As required
Boiler Cleaning
Antifoam Agent
GEOMELT
87,000 gallons
Winter months
Anti -icing Fluid for Coal
per month
BT -930
87,000 gallons
Winter months
Anti -icing Fluid for Coal
per month
Limestone (calcium
492,000 tons
Continuous
Flue Gas
carbonate)
Desulfurization
EN/ACT 7880
As Required
Coagulant for
Coal Pile Runoff
RO Clean P112
81 gallons per use
As required
R.O system cleaning
(estimated every 1-3
months)
RO Clean P111
81 gallons per use
As required
R.O. System cleaning
(estimated every 1-3
months)
Rev 10/06

Sumaclear 1000
6 gallons
Daily
R.O system treatment
VITEC 3000
5 gallons
Daily
R.O system treatment
Muriatic acid
1871 pounds
As required
R.O system cleaning
(estimated every 1-3
months
Citric Acid
675 pounds
As required
R.O. System cleaning
(estimated every 1-3
months
Magnesium
1 gallon per ton of
continuous
Slag mitigation
Hydroxide
coal
SO3 mitigation
Nalco BT 3000
1060 gallons
Per year
Boiler water treatment
Rev 10/06

Cc: Robert Howard
William Milam
Jodirah Green
Shannon Langley -OPEB4