NC0038377_Mayo 38377 major mod signed 2021_20211215

Permit NC0038377
STATE OF NORTH CAROLINA
DEPARTMENT OF ENVIRONMENTAL QUALITY
DIVISION OF WATER RESOURCES
PERMIT
TO DISCHARGE WASTEWATER UNDER THE
NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM
In compliance with the provision of North Carolina General Statute 143-215.1, other lawful standards and
regulations promulgated and adopted by the North Carolina Environmental Management Commission, and
the Federal Water Pollution Control Act, as amended,
Duke Energy Progress, LLC
is hereby authorized to discharge wastewater and stormwater from a facility located at the
Mayo Steam Electric Generating Plant
off of US Highway 501
northeast of Roxboro
Person County
to receiving waters designated as the Mayo Reservoir in the Roanoke River Basin in accordance with effluent
limitations, monitoring requirements, and other applicable conditions set forth in Parts I, II, and III hereof.
The permit modification shall become effective January 1, 2022.
This permit and the authorization to discharge shall expire at midnight on July 31, 2023.
Signed this day December 10, 2021.
for
DocuSigned by:
L
9 ?outran`
8FB19B649DD2478...
S. Daniel Smith, Director
Division of Water Resources
By Authority of the Environmental Management
Commission
Page 1 of 18

Permit NC0038377
SUPPLEMENT TO PERMIT COVER SHEET
All previous NPDES Permits issued to this facility, whether for operation or discharge are hereby revoked.
As of this permit issuance, any previously issued permit bearing this number is no longer effective. Therefore,
the exclusive authority to operate and discharge from this facility arises under the permit conditions,
requirements, terms, and provisions included herein.
Duke Energy Progress, LLC
is hereby authorized to:
1. Continue to operate the following systems located at Mayo Steam Electric Generating Plant, off of US
Highway 501, northeast of Roxboro, Person County:
• Outfall 001. Cooling Tower System. Less than once per year the cooling towers and circulating
water system are drained by gravity and discharged directly to Mayo Reservoir.
• Outfall 002. Ash Pond Treatment System. Outfall 002 discharges directly to Mayo Reservoir.
The ash pond receives coal pile runoff, stormwater runoff, cooling tower blowdown, and various
low volume wastes such as boiler blowdown, oily waste treatment, wastes/backwash from the
water treatment processes including Reverse -Osmosis (RO) wastewater, plant area wash down
water, equipment heat exchanger water, groundwater, yard sump overflows, occasional piping
leakage from limestone slurry and FGD system, and treated domestic wastewater.
• Internal Outfall 008. Cooling tower blowdown is directly discharged to the ash pond. Cooling
tower blowdown is indirectly discharged to Mayo Reservoir via the ash pond treatment system
(Outfall 002).
• Internal Outfall 009. Discharge from the FGD blowdown treatment system. FGD blowdown is
indirectly discharged to Mayo Reservoir via the ash pond treatment system (Outfall 002).
• Outfall 002A. Upon completion of construction, discharge from the new lined retention basin.
Basin will accept wastes from holding cell (vacuumed sediments and solids), coal pile runoff,
stormwater runoff, landfill leachate from CCR landfill, industrial stormwater from CCR landfill,
cooling tower blowdown, ammonia conversion maintenance drainage, and various low volume
wastes such as boiler blowdown, oily waste treatment, wastes/backwash from the water treatment
processes including Reverse -Osmosis (RO) wastewater, plant area wash down water, equipment
heat exchanger water, groundwater, occasional piping leakage from limestone slurry and FGD
system, chemical metal cleaning waste, and treated domestic wastewater. The wastewater from
this outfall discharges to Mayo reservoir via the Outfall 002 location.
• Internal Outfall 002B. Yard sump overflows (contain all wastes routed to the new retention
basin). The wastewater from this outfall discharges to Mayo reservoir via the Outfall 002.
• Internal outfall 011. Domestic wastewater plant. The wastewater from this outfall discharges to
Mayo Reservoir via Outfall 002.
2. Discharge from said treatment works and/or outfalls at the locations specified on the attached map into
Mayo Reservoir, which is classified as WS-V waters in the Roanoke River Basin.
Page 2 of 18

Permit NC0038377
Part I
A. (1.) EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS (Outfall 001)
[15A NCAC 02B .0400 et seq., 02B .0500 et seq.]
During the period beginning on the effective date of the permit and lasting until expiration, the Permittee is
authorized to discharge from Outfall 001 (Cooling Tower System). Monitoring is required only during
discharge events to the Mayo reservoir. Such discharges shall be limited and monitored' by the Permittee as
specified below:
PARAMETER
LIMITS
MONITORING REQUIREMENTS
Monthly
Average
Daily
Maximum
Measurement
Frequency
Sample Type
Sample
Locationl
Flow
Daily
Pump Logs or
similar readings
Effluent
Free Available
Chlorine2
200 µg/L
500 µg/L
Weekly
Grab
Effluent
Time of Chlorine
Addition2
2 hours
Weekly
Logs
Total Chromium3
0.2 mg/L
0.2 mg/L
2 / Month
Grab
Effluent
Total Zinc3
1.0 mg/L
1.0 mg/L
2 / Month
Grab
Effluent
Priority Pollutants 3
No Detectable Amount
Annual
Grab
Effluent
Temperature, °C
Daily
Grab
Effluent
pH
> 6.0 and < 9.0 standard units
Weekly
Grab
Effluent
Notes:
1. Samples taken in compliance with the monitoring requirements listed above shall consist of cooling tower
effluent prior to its discharge to Mayo Reservoir.
2. Monitoring is required only if chlorine -based compounds are added to the system. Neither free available
chlorine nor total residual chlorine may be discharged from any single generating unit for more than two
hours per day, unless the Permittee demonstrates to the Division of Water Resources that discharge for
more than two hours is required for macroinvertebrate control. The 500 µg/L limitation is an
instantaneous maximum and is to be measured during the chlorine release period. The 200 µg/L
limitation is an average during the chlorine release period. Simultaneous multi -unit chlorination is
permitted.
3 Limitations and monitoring requirements for the 126 Priority Pollutants (per 40 CFR Part 423, Appendix
A, exclusive of zinc and chromium) apply only if these substances are added by the permittee for cooling
tower maintenance. Compliance with the limitations for the 126 priority pollutants in 40 CFR 423.13
(d)(1) may be determined by engineering calculations which demonstrate that the regulated pollutants are
not detectable in the final discharge by the analytical methods in 40 CFR Part 136. All primary industries
are required to submit a priority pollutant analysis in accordance with 40 CFR Part 122 with their
application for permit renewal.
4. The permittee shall submit Discharge Monitoring Reports electronically using NC DWR's eDMR
application system. Please See Special Condition A. (12.).
The above listed effluent limitations shall be sampled prior to draining the cooling tower(s), at a location
prior to discharge to Mayo Reservoir. There shall be no discharge of polychlorinated biphenyl compounds
such as those commonly used for transformer fluid.
Page 3 of 18

Permit NC0038377
A. (2.) EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS (Internal Outfall 008)
[15A NCAC 02B .0400 et seq., 02B .0500 et seq.]
During the period beginning on the effective date of the permit and lasting until expiration, the Permittee is
authorized to discharge from Outfall 008 (Internal outfall, Cooling Tower System). Such discharges shall be
limited and monitored' by the Permittee as specified below:
PARAMETER
LIMITS
MONITORING REQUIREMENTS
Monthly
Average
Daily
Maximum
Measurement
Frequency
Sample
Type
Sample
Locationl
Flow
Daily
Pump Logs
or similar
readings
Effluent
Free Available
Chlorine2
200 µg/L
500 µg/L
Weekly
Grab
Effluent
Time of Chlorine
Addition2
2 hours
Weekly
Logs
Total Chromium3
0.2 mg/L
0.2 mg/L
2 / Month
Grab
Effluent
Total Zinc3
1.0 mg/L
1.0 mg/L
2 / Month
Grab
Effluent
Priority Pollutants 3
No Detectable Amount
Annual
Grab
Effluent
pH
> 6.0 and < 9.0 standard
units
Weekly
Grab
Effluent
Notes:
1. Samples taken in compliance with the monitoring requirements listed above shall consist of cooling
tower blowdown.
2. Monitoring is required only if chlorine -based compounds are added to the system. Neither free
available chlorine nor total residual chlorine may be discharged from any single generating unit for
more than two hours per day, unless the Permittee demonstrates to the Division of Water Resources
that discharge for more than two hours is required for macroinvertebrate control. The 500 µg/L
limitation is an instantaneous maximum and is to be measured during the chlorine release period.
The 200 µg/L limitation is an average during the chlorine release period. Simultaneous multi -unit
chlorination is permitted.
3 Limitations and monitoring requirements for the 126 Priority Pollutants (per 40 CFR Part 423,
Appendix A, exclusive of zinc and chromium) apply only if these substances are added by the
permittee for cooling tower maintenance. Compliance with the limitations for the 126 priority
pollutants in 40 CFR 423.13 (d)(1) may be determined by engineering calculations which demonstrate
that the regulated pollutants are not detectable in the final discharge by the analytical methods in 40
CFR Part 136. All primary industries are required to submit a priority pollutant analysis in
accordance with 40 CFR Part 122 with their application for permit renewal.
4. The permittee shall submit Discharge Monitoring Reports electronically using NC DWR's eDMR
application system. Please See Special Condition A. (12.).
This outfall is not authorized to discharge directly to the Mayo Reservoir.
Page 4 of 18

Permit NC0038377
A. (3.) EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS (Outfall 002-normal
operation/decanting)
[15A NCAC 02B .0400 et seq., 02B .0500 et seq.]
During the period beginning on the effective date of the permit and lasting until expiration, the Permittee is
authorized to discharge from Outfall002 (decanting the free water above the settled ash layer that does
not involve mechanical disturbance of the ash). These requirements shall remain in effect during
the term of the permit. Such discharges shall be limited and monitored' by the Permittee as specified below:
PARAMETER
LIMITS
MONITORING REQUIREMENTS
Monthly
Average
Daily
Maximum
Measurement
Frequency
Sample
Type
Sample
Location
Flow
Weekly
Pump Logs
or similar
readings
Effluent
Oil and Grease
15.0 mg/L
20.0 mg/L
Monthly
Grab
Effluent
Total Suspended Solids'
30.0 mg/L
50.0 mg/L
Monthly
Grab
Effluent
Turbidity', NTU
Monthly
Grab
Effluent
Total Selenium, µg/L
Weekly
Grab
Effluent
Total Chromium, µg/L
Monthly
Grab
Effluent
Total Copper, µg/L
Monthly
Grab
Effluent
Total Zinc, µg/L
Monthly
Grab
Effluent
Acute Toxicity'
Quarterly
Grab
Effluent
Total Mercury2
47 0 ng/L
Weekly
Grab
Effluent
Total Arsenic, µg/L
Weekly
Grab
Effluent
Total Beryllium
6.5 µg/L
65.0 µg/L
Weekly
Grab
Effluent
Total Chlorides
250.0 mg/L
250.0 mg/L
Weekly
Grab
Effluent
Total Fluoride
1,800.0 µg/L
1,800.0 µg/L
Weekly
Grab
Effluent
Total Barium, mg/L
Monthly
Grab
Effluent
Total Thallium, µg/L
Weekly
Grab
Effluent
Total Lead, µg/L
Monthly
Grab
Effluent
Total Nickel, µg/L
Monthly
Grab
Effluent
Total Antimony, µg/L
Monthly
Grab
Effluent
Total Boron, mg/L
Monthly
Grab
Effluent
Temperature, °C
Daily
Grab
Effluent
pH6
> 6.0 and < 9.0 standard units
2 / Month
Grab
Effluent
Notes:
Samples taken in compliance with the monitoring requirements listed above shall be taken prior to mixing
with other waste streams.
1. Acute Toxicity (Fathead Minnow 24-hr) No significant mortality at 90%. Please See Special
Condition A. (9.).
2. The facility shall use EPA method 1631E. The limit is an annual average limit based on a calendar
year.
3. The permittee shall submit Discharge Monitoring Reports electronically using NC DWR's eDMR
application system. Please See Special Condition A. (12.).
4. The discharge from this facility shall not cause turbidity in the receiving stream to exceed 25 NTU. If
the instream turbidity exceeds 25 NTU due to natural background conditions, the discharge cannot
cause turbidity to increase in the receiving stream. Therefore, if the effluent measurement exceeds 25
Page 5 of 18

Permit NC0038377
NTU, the Permittee shall sample upstream and downstream turbidity in the receiving waterbody,
within 24 hours, to demonstrate the existing turbidity level in the receiving waterbody was not
increased. All data shall be reported on the DMRs. (See 15A NCAC 2B .0211 (21)).
NTU - Nephelometric Turbidity Unit.
5. The facility shall continuously monitor TSS concentration when the decanting process commences
and the pump shall be shutoff automatically when one half of the Daily Maximum limit (15 minutes
average) is exceeded. Pumping will be allowed to continue if interruption might result in a dam failure
or damage. The continuous TSS monitoring is only required when the pumps are employed.
6. The facility shall continuously monitor pH when the decanting process commences and the decanting
pump shall be shutoff automatically when 15 minutes running average pH falls below 6.1 standard
units or rises above 8.9 standard units. Pumping will be allowed to continue if interruption might
result in a dam failure or damage. The continuous pH monitoring is only required when the pumps
are employed.
There shall be no discharge of floating solids or visible foam in other than trace amounts outside an area five
(5) meters from the discharge pipe. There shall be no discharge of polychlorinated biphenyl compounds
such as those commonly used for transformer fluid.
The facility is allowed to drawdown the wastewater in the ash pond to no less than three feet above
the ash. The rate for lowering the liquid level in a coal ash pond shall not exceed one (1) foot per day
unless a higher rate is supported to the satisfaction of DEMLR and in accordance with NCAC, Title
15A, Subchapter 2K.
The facility shall use a floating pump station with free water skimmed from the basin surface using
an adjustable weir.
The limits and conditions in Section A. (4.) of the permit apply when water in the ash settling basin
is lowered below the three feet trigger mark.
By November 1, 2018 there shall be no discharge of pollutants in fly ash transport water. This
requirement only applies to fly ash transport water generated after November 1, 2018. By November
1, 2018 there shall be no discharge of pollutants in bottom ash transport water. This requirement
only applies to bottom ash transport water generated after November 1, 2018.
The facility shall notify DWR Complex NPDES Permitting Unit and DWR Raleigh Regional
Office, in writing, seven calendar days prior to the commencement of the decanting.
When the facility commences the ash pond/ponds decanting, the facility shall treat the wastewater
discharged from the ash pond/ponds using physical -chemical treatment, if necessary, to assure
state Water Quality Standards are not contravened in the receiving stream. Duke Energy shall notify
DWR NPDES Permitting and DWR Raleigh Regional Office, in writing, within seven calendar days
of installing additional physical -chemical treatment at this Outfall.
If any one of the pollutants (As, Se, Hg, Ni, and Pb) reaches 85% of the allowable level during the
decanting/dewatering, the facility shall immediately discontinue discharge of the wastewater and
report it to the Regional Office and Complex NPDES Permitting Branch via telephone and e-mail.
Page 6 of 18

Permit NC0038377
A. (4.) EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS- (Outfall 002-
dewatering)
[15A NCAC 02B .0400 et seq., 02B .0500 et seq.]
During the period beginning on the effective date of the permit and lasting until expiration, the Permittee is
authorized to discharge from Outfall002 (dewatering-removing the interstitial water). Such discharges
shall be limited and monitored' by the Permittee as specified below:
PARAMETER
LIMITS
MONITORING REQUIREMENTS
Monthly
Average
Daily
Maximum
Measurement
Frequency
Sample
Type
Sample
Location
Flow
3.0 MGD8
Weekly
Pump Logs
or similar
readings
Effluent
Oil and Grease
15.0 mg/L
20.0 mg/L
Weekly
Grab
Effluent
Total Suspended Solids'
30.0 mg/L
50.0 mg/L
Weekly
Grab
Effluent
Turbidity', NTU
Weekly
Grab
Effluent
Total Selenium, µg/L
Weekly
Grab
Effluent
Acute Toxicity'
Monthly
Grab
Effluent
Total Mercury', ng/L
Weekly
Grab
Effluent
Total Arsenic
10.0 µg/L
340.0 µg/L
Weekly
Grab
Effluent
Total Cadmium
0.59 µg/L
3.24 µg/L
Weekly
Grab
Effluent
Total Chlorides
250.0 mg/L
250.0 mg/L
Weekly
Grab
Effluent
Chromium (111)6
117.7 µg/L
905.1 µg/L
Weekly
Grab
Effluent
Chromium (VI)
11.0 µg/L
16.0 µg/L
Weekly
Grab
Effluent
Total Chromium, µg/L
Weekly
Grab
Effluent
Total Copper
7.88 µg/L
10.47 µg/L
Weekly
Grab
Effluent
Total Fluoride, µg/L
Weekly
Grab
Effluent
Total Lead
2.94 µg/L
75.5 µg/L
Weekly
Grab
Effluent
Total Nickel
25.0 µg/L
335.2 µg/L
Weekly
Grab
Effluent
Total Zinc
126.7 µg/L
125.7 µg/L
Weekly
Grab
Effluent
Total Barium
1.0 mg/L
1.0 mg/L
Weekly
Grab
Effluent
Total Thallium
2.0 µg/L
2.0 µg/L
Weekly
Grab
Effluent
Total Antimony, µg/L
Weekly
Grab
Effluent
Total Boron, mg/L
Weekly
Grab
Effluent
Temperature, °C
Daily
Grab
Effluent
pH'
> 6.0 and < 9.0 standard units
Weekly
Grab
Effluent
Notes:
Samples taken in compliance with the monitoring requirements listed above shall be taken prior to mixing
with other waste streams.
1. Acute Toxicity (Fathead Minnow 24-hr) No significant mortality at 90%; Please see Special Condition
A. (9).
2. The facility shall use EPA method 1631E.
3. The permittee shall submit Discharge Monitoring Reports electronically using NC DWR's eDMR
application system. Please See Special Condition A. (12.).
4. The discharge from this facility shall not cause turbidity in the receiving stream to exceed 25 NTU. If
the instream turbidity exceeds 25 NTU due to natural background conditions, the discharge cannot
cause turbidity to increase in the receiving stream. Therefore, if the effluent measurement exceeds 25
Page 7 of 18

Permit NC0038377
NTU, the Permittee shall sample upstream and downstream turbidity in the receiving waterbody,
within 24 hours, to demonstrate the existing turbidity level in the receiving waterbody was not
increased. All data shall be reported on the DMRs. (See 15A NCAC 2B .0211 (21)).
NTU - Nephelometric Turbidity Unit.
5. The facility shall continuously monitor TSS concentration when the dewatering process commences
and the pump shall be shutoff automatically when one half of the Daily Maximum limit (15 minutes
average) is exceeded. Pumping will be allowed to continue if interruption might result in a dam failure
or damage. The continuous TSS monitoring only required when the pumps are employed.
6. Cr(III)=Total Chromium-Chromium(VI).
7. The facility shall continuously monitor pH when the dewatering process commences and the
dewatering pump shall be shutoff automatically when 15 minutes running average pH falls below 6.1
standard units or rises above 8.9 standard units. Pumping will be allowed to continue if interruption
might result in a dam failure or damage. The continuous pH monitoring only required when the
pumps are employed.
8. The flow limit applies only to the water removed from the interstitial pore space.
There shall be no discharge of floating solids or visible foam in other than trace amounts outside an area five
(5) meters from the discharge pipe. There shall be no discharge of polychlorinated biphenyl compounds
such as those commonly used for transformer fluid.
The rate for lowering the liquid level in a coal ash pond shall not exceed one (1) foot per day unless a
higher rate is supported to the satisfaction of DEMLR and in accordance with NCAC, Title 15A,
Subchapter 2K.
By November 1, 2018 there shall be no discharge of pollutants in fly ash transport water. This
requirement only applies to fly ash transport water generated after November 1, 2018.
By November 1, 2018 there shall be no discharge of pollutants in bottom ash transport water. This
requirement only applies to bottom ash transport water generated after November 1, 2018.
The facility shall notify DWR Complex NPDES Permitting Unit and DWR Raleigh Regional
Office, in writing, seven calendar days prior to the commencement of the dewatering.
When the facility commences the ash pond/ponds dewatering, the facility shall treat the wastewater
discharged from the ash pond/ponds using physical -chemical treatment, if necessary, to assure
state Water Quality Standards are not contravened in the receiving stream. Duke Energy shall notify
DWR NPDES Permitting and DWR Raleigh Regional Office, in writing, within seven calendar days
of installing additional physical -chemical treatment at this Outfall.
If any one of the pollutants (As, Se, Hg, Ni, and Pb) reaches 85% of the allowable level during the
decanting/dewatering, the facility shall immediately discontinue discharge of the wastewater and
report it to the Regional Office and Complex NPDES Permitting Branch via telephone and e-mail.
Page 8 of 18

Permit NC0038377
A. (5.) EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS (Outfall 002A)
[15A NCAC 02B .0400 et seq., 02B .0500 et seq.]
During the period beginning upon the commencement of operations of the new Retention Basin and lasting
until expiration, the Permittee is authorized to discharge from Internal Outfall 002A (new retention basin).
Such discharges shall be limited and monitored2 by the Permittee as specified below:
PARAMETER
LIMITS
MONITORING REQUIREMENTS
Monthly
Average
Daily
Maximum
Measurement
Frequency
Sample
Type —
Sample
Location
Flow, MGD
Weekly
Instantaneous
Effluent
Oil and Grease
15.0 mg/L
20.0 mg/L
Quarterly
Grab
Effluent
Total Suspended Solids
30.0 mg/L
50.0 mg/L
Quarterly
Grab
Effluent
Temperature, °C
Daily
Grab
Effluent
Total Arsenic
10.0 1.1g/L3
340.0 µg/L3
Monthly
Grab
Effluent
Total Mercury', ng/L
Quarterly
Grab
Effluent
Total Selenium, µg/L
Quarterly
Grab
Effluent
Nitrate/nitrite as N,
mg/L
Quarterly
Grab
Effluent
Total Chlorides
230.0 mg/L3
230.0 mg/L3
Monthly
Grab
Effluent
Total Nickel, µg/L
Quarterly
Grab
Effluent
Total Sulfate, mg/L
Quarterly
Grab
Effluent
Total Fluoride
1,800.0 µg/L3
1,800.0 µg/L3
Monthly
Grab
Effluent
Total Barium
1.0 mg/L3
1.0 mg/L3
Monthly
Grab
Effluent
Total Antimony
5.6 µg/L3
5.6 µg/L3
Monthly
Grab
Effluent
Total Chromium, µg/L
Quarterly
Grab
Effluent
Notes:
1. The facility shall use EPA method 1631E.
2. The permittee shall submit Discharge Monitoring Reports electronically using NC DWR's eDMR
application system. Please See Special Condition A. (12.).
3. Limits and monitoring become effective upon the beginning of the release of leachate. The permittee must
notify the Division in writing 7 days prior to the commencement of the CCR leachate discharge.
There shall be no discharge of floating solids or visible foam in other than trace amounts outside an area five
(5) meters from the discharge pipe. There shall be no discharge of polychlorinated biphenyl compounds
such as those commonly used for transformer fluid.
The sampling from Outfall 002A should be conducted separately from the sampling for Outfall 002.
Page 9 of 18

Permit NC0038377
A. (6.) EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS (Internal Outfall 002B)
[15A NCAC 02B .0400 et seq., 02B .0500 et seq.]
During the period beginning on the effective date of the permit and lasting until expiration, the Permittee is
authorized to discharge from Internal Outfall 002B (yard sump overflow). Such discharges shall be limited
and monitored' by the Permittee as specified below:
PARAMETER
LIMITS
REQUIREMENTS
MONITORING
Monthly
Average
Daily
Maximum
Measurement
Frequency
Sample
Type
Sample
Location
Flow, MGD
Per discharge
event
Pump logs or
estimate
Effluent
Oil and Grease
15.0 mg/L
20.0 mg/L
Per discharge
event
Grab
Effluent
Total Suspended Solids
30.0 mg/L
50.0 mg/L
Per discharge
event
Grab
Effluent
pH, standard units
Per discharge
event
Grab
Effluent
Notes:
1. The permittee shall submit Discharge Monitoring Reports electronically using NC DWR's eDMR
application system. Please See Special Condition A. (12.).
A. (7.) EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS (Internal Outfall 009)
[15A NCAC 02B .0400 et seq., 02B .0500 et seq.]
During the period beginning on the effective date of the permit and lasting until expiration, the Permittee is
authorized to discharge from Internal Outfall 009 (treated FGD wet scrubber wastewater). Such discharges
shall be limited and monitored' by the Permittee as specified below:
PARAMETER
LIMITS
REQUIREMENTS
MONITORING
Monthly
Average
Daily
Maximum
Measurement
Frequency
Sample
Type
Sample
Location
Flow, MGD
Weekly
Instantaneous
Effluent
Total Arsenic
8.0 µg/L2
11.0 1.1g/L2
Quarterly
Grab
Effluent
Total Mercury'
356.0 ng/L2
788.0 ng/L2
Quarterly
Grab
Effluent
Total Selenium
12.0 µg/L2
23.0 µg/L2
Quarterly
Grab
Effluent
Nitrate/nitrite as N
4.4 mg/L2
17.0 mg/L2
Quarterly
Grab
Effluent
Oil and Grease
15.0 mg/L
20.0 mg/L
Quarterly
Grab
Effluent
Total Suspended
Solids
30.0 mg/L
50.0 mg/L
Quarterly
Grab
Effluent
Notes:
1. The permittee shall submit Discharge Monitoring Reports electronically using NC DWR's eDMR
application system. Please See Special Condition A. (12.).
2. The TBEL limits shall become effective on November 1, 2018.
3. The facility shall use EPA method 1631E.
Page 10 of 18

Permit NC0038377
A. (8.) EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS (Internal Outfall 011)
[15A NCAC 02B .0400 et seq., 02B .0500 et seq.]
During the period beginning on the effective date of the permit and lasting until expiration, the Permittee is
authorized to discharge from Internal Outfall 011 (domestic wastewater plant). Such discharges shall be
limited and monitored' by the Permittee as specified below:
PARAMETER
LIMITS
MONITORING REQUIREMENTS
Monthly
Average
Daily
Maximum
Measurement
Frequency
Sample
_ Type _
Sample
Location
Flow, MGD
Quarterly
Instantaneous
Effluent
BOD, 5-day, 20° C
30.0 mg/L
45.0 mg/L
Quarterly
Grab
Effluent
TSS
30.0 mg/L
45.0 mg/L
Quarterly
Grab
Effluent
Fecal Coliform (geo. mean)
200/100 mL
400/100 mL
Quarterly
Grab
Effluent
Notes:
1. The permittee shall submit Discharge Monitoring Reports electronically using NC DWR's eDMR
application system. Please See Special Condition A. (12.).
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Permit NC0038377
A. (9.) ACUTE TOXICITY PASS/FAIL PERMIT LIMIT (Monthly/Quarterly) (Outfall 002)
[15A NCAC 02B .0400 et seq., 02B .0500 et seq.]
The permittee shall conduct acute toxicity tests on a monthly/quarterly basis using protocols defined in the North
Carolina Procedure Document entitled "Pass/Fail Methodology for Determining Acute Toxicity In A Single
Effluent Concentration" (Revised July, 1992 or subsequent versions). The monitoring shall be performed as a
Fathead Minnow (Pimephales promelas) 24 hour static test. The effluent concentration at which there may be at
no time significant acute mortality is 90% (defined as treatment two in the procedure document). Effluent
samples for self -monitoring purposes must be obtained during representative effluent discharge below all waste
treatment.
All toxicity testing results required as part of this permit condition will be entered on the Effluent Discharge
Monitoring Form (MR-1) for the month in which it was performed, using the parameter code TGE6C.
Additionally, DWR Form AT-2 (original) is to be sent to the following address:
Attention: North Carolina Division of Water Resources
Water Sciences Section
1621 Mail Service Center
Raleigh, North Carolina 27699-1621
Or, results can be sent to the email: [e-mail]
Completed Aquatic Toxicity Test Forms shall be filed with the Water Sciences Section no later than 30 days
after the end of the reporting period for which the report is made.
Test data shall be complete and accurate and include all supporting chemical/physical measurements
performed in association with the toxicity tests, as well as all dose/response data. Total residual chlorine of the
effluent toxicity sample must be measured and reported if chlorine is employed for disinfection of the waste
stream.
Should there be no discharge of flow from the facility during a month in which toxicity monitoring is required,
the permittee will complete the information located at the top of the aquatic toxicity (AT) test form indicating
the facility name, permit number, pipe number, county, and the month/year of the report with the notation of
"No Flow" in the comment area of the form. The report shall be submitted to the Water Sciences Section at
the address cited above.
Should any test data from either these monitoring requirements or tests performed by the North Carolina
Division of Water Resources indicate potential impacts to the receiving stream, this permit may be re -opened
and modified to include alternate monitoring requirements or limits.
NOTE: Failure to achieve test conditions as specified in the cited document, such as minimum control
organism survival and appropriate environmental controls, shall constitute an invalid test and will require
immediate follow-up testing to be completed no later than the last day of the month following the month of
the initial monitoring.
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Permit NC0038377
A. (10.) DOMESTIC WASTEWATER TREATMENT PLANT
[40 CFR 133]
The domestic wastewater treatment plant shall be properly operated and maintained to ensure treatment of
domestic wastewater to secondary levels.
A. (11.) ADDITIONAL CONDITIONS AND DEFINITIONS
[NCGS 143-215.3 (a) (2) and NCGS 143-215.66]
1. EPA methods 200.7 or 200.8 (or the most current versions) shall be used for analyses of all metals
except for total mercury (EPA Method 1631E).
2. All effluent samples for all external outfalls shall be taken at the most accessible location after the
final treatment but prior to discharge to waters of the U.S. (40 CFR 122.41(j)).
3. The term low volume waste sources mean wastewater from all sources except those for which specific
limitations are otherwise established in this part (40 CFR 423.11 (b)).
4. The term chemical metal cleaning waste means any wastewater resulting from cleaning any metal process
equipment with chemical compounds, including, but not limited to, boiler tube cleaning (40 CFR
423.11 (c)).
5. The term metal cleaning waste means any wastewater resulting from cleaning [with or without chemical
cleaning compounds] any metal process equipment including, but not limited to, boiler tube cleaning,
boiler fireside cleaning, and air preheater cleaning (40 CFR 423.11 (d)).
6. For all outfalls where the flow measurement is to be "estimated" the estimate can be done by using
calibrated V-notch weir, stop -watch and graduated cylinder, or other method approved by the
Division.
7. The term "FGD wet scrubber wastewater" means wastewater resulting from the use of the flue -gas
desulfurization wet scrubber.
8. There shall be no discharge of polychlorinated biphenyl compounds.
9. The permittee shall report the presence of cenospheres observed in any samples on the DMRs.
10. The applicant is permitted to discharge chemical metal cleaning wastes to the ash basin.
11. Nothing contained in this permit shall be construed as a waiver by the permittee of any right to a
hearing it may have pursuant to State or Federal laws and regulations.
A. (12.) ELECTRONIC REPORTING OF DISCHARGE MONITORING REPORTS
[G.S. 143-215.1(b)]
Federal regulations require electronic submittal of all discharge monitoring reports (DMRs) and program
reports. The final NPDES Electronic Reporting Rule was adopted and became effective on December 21,
2015.
NOTE: This special condition supplements or supersedes the following sections within Part II of this permit
(Standard Conditions forNPDES Permits):
• Section B. (11.)
• Section D. (2.)
• Section D. (6.)
• Section E. (5.)
Signatory Requirements
Reporting
Records Retention
Monitoring Reports
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Permit NC0038377
1. Reporting Requirements [Supersedes Section D. (2.) and Section E. (5.) (a)]
The permittee shall report discharge monitoring data electronically using the NC DWR's Electronic
Discharge Monitoring Report (eDMR) internet application.
Monitoring results obtained during the previous month(s) shall be summarized for each month and
submitted electronically using eDMR. The eDMR system allows permitted facilities to enter monitoring
data and submit DMRs electronically using the internet. Until such time that the state's eDMR
application is compliant with EPA's Cross -Media Electronic Reporting Regulation (CROMERR),
permittees will be required to submit all discharge monitoring data to the state electronically using eDMR
and will be required to complete the eDMR submission by printing, signing, and submitting one signed
original and a copy of the computer printed eDMR to the following address:
NC DENR / Division of Water Resources / Water Quality Permitting Section
ATTENTION: Central Files
1617 Mail Service Center
Raleigh, North Carolina 27699-1617
If a permittee is unable to use the eDMR system due to a demonstrated hardship or due to the facility
being physically located in an area where less than 10 percent of the households have broadband access,
then a temporary waiver from the NPDES electronic reporting requirements may be granted and
discharge monitoring data may be submitted on paper DMR forms (MR 1, 1.1, 2, 3) or alternative forms
approved by the Director. Duplicate signed copies shall be submitted to the mailing address above. See
"How to Request a Waiver from Electronic Reporting" section below.
Regardless of the submission method, the first DMR is due on the last day of the month following the
issuance of the permit or in the case of a new facility, on the last day of the month following the
commencement of discharge.
Starting on December 21, 2020, the permittee must electronically report the following compliance
monitoring data and reports, when applicable:
• Sewer Overflow/Bypass Event Reports;
• Pretreatment Program Annual Reports; and
• Clean Water Act (CWA) Section 316(b) Annual Reports.
The permittee may seek an electronic reporting waiver from the Division (see "How to Request a Waiver
from Electronic Reporting" section below).
2. Electronic Submissions
In accordance with 40 CFR 122.41(1) (9), the permittee must identify the initial recipient at the time of
each electronic submission. The permittee should use the EPA's website resources to identify the initial
recipient for the electronic submission.
Initial recipient of electronic NPDES information from NPDES-regulated facilities means the entity
(EPA or the state authorized by EPA to implement the NPDES program) that is the designated entity for
receiving electronic NPDES data [see 40 CFR 127.2(b)].
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Permit NC0038377
EPA plans to establish a website that will also link to the appropriate electronic reporting tool for each
type of electronic submission and for each state. Instructions on how to access and use the appropriate
electronic reporting tool will be available as well. Information on EPA's NPDES Electronic Reporting
Rule is found at: http://www2.epa.gov/compliance/final-national-pollutant-discharge-elimination-
system-npdes-electronic-reporting-rule.
Electronic submissions must start by the dates listed in the "Reporting Requirements" section above.
3. How to Request a Waiver from Electronic Reporting
The permittee may seek a temporary electronic reporting waiver from the Division. To obtain an
electronic reporting waiver, a permittee must first submit an electronic reporting waiver request to the
Division. Requests for temporary electronic reporting waivers must be submitted in writing to the
Division for written approval at least sixty (60) days prior to the date the facility would be required under
this permit to begin submitting monitoring data and reports. The duration of a temporary waiver shall
not exceed 5 years and shall thereupon expire. At such time, monitoring data and reports shall be
submitted electronically to the Division unless the permittee re -applies for and is granted a new
temporary electronic reporting waiver by the Division. Approved electronic reporting waivers are not
transferrable. Only permittees with an approved reporting waiver request may submit monitoring data
and reports on paper to the Division for the period that the approved reporting waiver request is
effective.
Information on eDMR and the application for a temporary electronic reporting waiver are found on the
following web page:
http: / /deq.nc.gov/about/divisions /water -resources /edmr
4. Signatory Requirements [Supplements Section B. (11.) (b) and Supersedes Section B. (11.) (d)]
All eDMRs submitted to the permit issuing authority shall be signed by a person described in Part II,
Section B. (11.)(a) or by a duly authorized representative of that person as described in Part II, Section B.
(11.)(b). A person, and not a position, must be delegated signatory authority for eDMR reporting
purposes.
For eDMR submissions, the person signing and submitting the DMR must obtain an eDMR user account
and login credentials to access the eDMR system. For more information on North Carolina's eDMR
system, registering for eDMR and obtaining an eDMR user account, please visit the following web page:
http: / /deq.nc.gov/about/divisions /water -resources /edmr
Certification. Any person submitting an electronic DMR using the state's eDMR system shall make the
following certification [40 CFR 122.22]. NO OTHER STATEMENTS OF CERTIFICATION WILL
BE ACCEPTED:
"I cert, under penalg 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 ystem, or those persons directly responsible forgathering the
information, the information submitted is, to the best of my knowledge and belief, true, accurate, and complete. I am aware
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Permit NC0038377
that there are significant penalties for submitting false information, including the possibility of fines and imprisonment for
knowing violations."
5. Records Retention [Supplements Section D. (6.)]
The permittee shall retain records of all Discharge Monitoring Reports, including eDMR submissions.
These records or copies shall be maintained for a period of at least 3 years from the date of the report.
This period may be extended by request of the Director at any time [40 CFR 122.41].
A. (13.) COMPLIANCE BOUNDARY
[15A NCAC 02L.0107]
The compliance boundary for the disposal system shall be specified in accordance with 15A NCAC 02L
.0107(a) or (b) dependent upon the date permitted. An exceedance of groundwater standards at or beyond
the compliance boundary is subject to remediation action according to 15A NCAC 02L .0106(c), (d), or (e) as
well as enforcement actions in accordance with North Carolina General Statute 143-215.6A through 143-
215.6C. The compliance boundary maps for this facility are incorporated herein and attached hereto as
Attachments A and B.
A. (14.) STRUCTURAL INTEGRITY INSPECTIONS of ASH POND DAM
[15A NCAC 02K.0208]
The facility shall meet the dam design and dam safety requirements per 15A NCAC 2K.
A. (15.) CLEAN WATER ACT SECTION 316 (B)
[40 CFR 125.95]
The permittee shall comply with the Cooling Water Intake Structure Rule per 40 CFR 125.95. The permittee
shall submit all the materials required by the Rule with the next renewal application.
Copies of all the study plans, study results, and any other applicable materials should be submitted to:
1) Electronic Version Only (pdf and CD)
Division of Water Resources
WQ Permitting Section - NPDES
1617 Mail Service Center
Raleigh, NC 27699-1617
2) Electronic Version (pdf and CD) and Hard Copy
Division of Water Resources
Water Sciences Section
1623 Mail Service Center
Raleigh, NC 27699-1623
Pursuit to 40 CFR 125.98 the Director has determined that operating and maintaining the existing Closed -
cycle recirculating system meets the requirements for an interim BTA.
Nothing in this permit authorizes take for the purposes of a facility's compliance with the Endangered Species
Act.
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Permit NC0038377
A. (16.) FISH TISSUE MONITORING NEAR ASH POND DISCHARGE — OUTFALL 002
[NCGS 143-215.3 (a) (2)]
The facility shall conduct fish tissue monitoring annually and submit the results with the NPDES permit
renewal application. The objective of this monitoring is to evaluate potential uptake of pollutants by fish tissue
near the ash pond discharge. The parameters analyzed in fish tissue shall include arsenic, selenium, and
mercury. The monitoring shall be conducted in accordance with the sampling plan approved by the Division.
The plan should be submitted to the Division within 180 days from the effective date of the permit. Upon
approval, the plan becomes an enforceable part of the permit.
Copies of all the study plans, study results, and any other applicable materials should be submitted to:
1) Electronic Version Only (pdf and CD)
Division of Water Resources
WQ Permitting Section - NPDES
1617 Mail Service Center
Raleigh, NC 27699-1617
2) Electronic Version (pdf and CD) and Hard Copy
Division of Water Resources
Water Sciences Section
1621 Mail Service Center
Raleigh, NC 27699-1621
A. (17.) INSTREAM MONITORING
[15A NCAC 02B.0500 ET SEQ.]
The facility shall conduct monthly in -stream monitoring (-550 ft. from Outfall 002 at sampling station B1) for
total arsenic, total selenium, total mercury, total chromium, dissolved lead, dissolved cadmium, dissolved
copper, dissolved zinc, total bromide, total hardness (as CaCO3), turbidity, temperature, and total dissolved
solids (TDS). The monitoring results shall be reported on the facility's Discharge Monitoring Reports and
included with the NPDES permit renewal application.
A. (18.) BIOCIDE CONDITION
[NCGS 143-215.1]
The permittee shall not use any biocides except those approved in conjunction with the permit application.
The permittee shall notify the Director in writing not later than ninety (90) days prior to instituting use of any
additional biocide used in cooling systems which may be toxic to aquatic life other than those previously
reported to the Division of Water Resources. Such notification shall include completion of Biocide Worksheet
Form 101 and a map locating the discharge point and receiving stream. Completion of Biocide Worksheet
Form 101 is not necessary for those outfalls containing toxicity testing. Division approval is not necessary for
the introduction of new biocides into outfalls currently tested for whole effluent toxicity.
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Permit NC0038377
A. (19.) APPLICABLE STATE LAW (State Enforceable Only)
[NCGS 143-215.1(b)]
This facility shall meet the General Statute requirements under NCGS § 130A-309.200 et seq. This permit may
be reopened to include new requirements imposed under these Statutes.
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