NC0000396_Modification_20191211 (2)

(� DUKE
ENERGY,
PROGRESS
Certified Mail: 7014 1820 0001 7891 3459
File: 125206
December 4, 2019 DEC i 1 yp�g w!
Julie Grzyb Water Quality Re
NPDES Complex Permitting Unitall Department of Environmental QutyAsheville Regional Offceional t10ns
1617 Mail Service Center
Raleigh, NC 27699-1617
Subject: Asheville Steam Electric Generating Plant
NPDES Permit NC0000396
Outfall 002 NPDES Permit Modification Request
Dear Ms. Grzyb:
Garry A. Whlsnent
Plant General Manager
Asheville Steam Electric Plant
Duke Energy Progress
ASVL PLTl200 CP&L Dr
Arden, NC 28704
o: 828-687-5211
f. 828-687.5204
garry wMsnanl®duke-energy.com
Asheville Steam Electric Generating Plant coal units are retiring soon. These coal units
will then proceed with decommissioning activities. The shutting down of operational
systems and decommissioning activities will warrant the need to modify the NPDES
permit. It is requested that the NPDES permit be modified to reflect the NPDES related
changes. The following and attachments provide the details associated with this permit
modification request.
The Condenser Cooling Water (CCW) system currently discharges through NPDES
Outfall 002 into Lake Julian. When the coal units are retired this system will no longer
discharge into Lake Julian. The current average flow from the CCW system is
approximately 255 mgd.
The cooling water from the evaporator system for the Combustion Turbines currently
discharges into the 64-ash basin, which discharges through NPDES Outfall 001. One
of the initial decommissioning activities is to modify the evaporator system's cooling
water flow path to discharge into the treatment pond that the CCW system currently
discharges into and then exit Outfall 002 into Lake Julian. This treatment pond also
receives storm water.
The evaporator system is used to cool air at ambient temperatures by the water flowing
across filter media into the Combustion Turbine Air Inlet. The cooling of the air
increases the combustion efficiency and maintains megawatt production level in the
warmer months. There are no chemicals added to the evaporator system. The source
of water is service water (raw lake water) from Lake Julian.

Julie Grzyb
Department of Environmental Quality
NPDES Complex Permitting Unit
December 4, 2019
The evaporator system is operated typically from May through October. The average
flowrate from this system is estimated to be 56 gpm (0.08 mgd). The temperature of this
discharge is close to ambient. The evaporator discharge will not begin to discharge to
Outfall 002 until after the CCW flow has stopped. The future flow and heat load from
the evaporator at Outfall 002 will be significantly less in comparison to the current CCW
discharge.
Therefore, it is requested that Outfall 002 be modified to include the discharge from the
evaporator system and to reflect shutting down of the coal station's CCW. Continuous
thermal, flow and chlorine sampling associated with the CCW flows are requested to be
removed with this modification as the addition of chlorine at the intake structure has
ceased.
Attached are sample results from the evaporator cooling water, a process flow diagram
that shows the evaporator, an aerial photo identifying the flow paths for the changes
described in this submittal and a check for $1,030 to process this permit modification
request.
Should you have questions or need additional information please contact Robert Wylie
at 704 382.4669.
Sincerely,
Garry Whisnant, Plant Manager
GM II - Regulated Stations
Attachments:
A. Evaporator Analytical Data
B. Process Flow Diagram
C. Aerial Photos Illustrating Current and Future Flow Paths
D. Check for Modification Fee
cc: Landon Davidson, DEQ, Asheville Regional Office
Teresa Williams, Duke Energy
Robert Wylie, Duke Energy

Attachment A
Evaporator Analytical Data
I
DCC i i 10i9
Water Quality Regional Operations
Asheville Regional Office

Asheville Electric Power Plant
NPDES Permit # NC0000396
Evaporator Cooling Water Analytical Results
Item
Parameter
Concentration
1
Chloride
17.2 mg/L
2
Chromium
0.80 ug/L
3
Copper
2.4 ug/L
4
Hardness
26 mg/L
5
Iron
61.9 ug/L
6
Magnesium
3.1 mg/L
7
Manganese
12.8 ug/L
8
Nickel
ND
9
Oil and Grease
ND
10
Sulfate
6.2 mg/L
11
TDS
99.0 mg/L
12
TSS
ND
13
Zinc
ND
ND = Not Detected
Note the temperature should be approximately the same as the ambient
temperature.

Attachment B
Process Flow Diagram

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Attachment C
Aerial Photos Illustrating Current and Future Flow Paths

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Attachment D
Check for Modification Fee