NC0003433_Fact Sheet_20240119

Fact Sheet
NPDES Permit No. NCO003433
Permit Writer/Email Contact: Sergei Chernikov, Ph.D., [e-mail]
Date: May 27, 2020
Division/Branch: NC Division of Water Resources/NPDES Complex Permitting
Fact Sheet Template: Version 09Jan2017
Permitting Action:
❑X Renewal
❑ Renewal with Expansion
❑ New Discharge
❑ Modification (Fact Sheet should be tailored to mod request)
Note: A complete application should include the following:
• For New Dischargers, EPA Form 2A or 2D requirements, Engineering Alternatives Analysis, Fee
• For Existing Dischargers (POTW), EPA Form 2A, 3 effluent pollutant scans, 4 2nd species WET
tests.
• For Existing Dischargers (Non-POTW), EPA Form 2C with correct analytical requirements based
on industry category.
Complete applicable sections below. If not applicable, enter NA.
1. Basic Facility Information
Facility Information
Applicant/Facility Name:
Duke Energy Progress LLC — Cape Fear Steam Electric Plant
Applicant Address:
500 CP&L Road, Moncure, NC 27599
Facility Address:
500 CP&L Road, Moncure, NC 27599
Permitted Flow:
Outfall 007 — 0.73 MGD Daily Maximum
Outfall 008 — 0.72 MGD Daily Maximum
Outfall 009 — 0.005 MGD Daily Maximum
Facility Type/Waste:
100% Industrial (Ash basin clean up, remediation)
Facility Class:
Grade I Physical Chemical WPCS
County:
Chatham
Region
Raleigh
Briefly describe the proposed permitting action and facility background.- This is a renewal of the
NPDES permit for Progress Duke Energy Progress 400 megawatt (Mwe) steam electric power plant on
the Cape Fear River in Moncure, North Carolina. The facility operated two coal fired units with a total net
generating capacity of 316 Mwe, two waste heat recovery units with a total net capacity of 28 MWe, and
four internal combustion turbines with a total net capacity of 56 MWe. The facility retired in 2011.
Page 1 of 16

This facility withdrew water from the Cape Fear River just downstream of the confluence of the Deep and
Haw Rivers. Outfalls discharge to a channel (designated as an unnamed tributary to the Cape Fear River)
just upstream of Buckhom Dam in Chatham County.
The facility operated three internal wastewater outfalls (001, 003, and 005) and one outfall that is the
combination of the three (outfall 007). Outfall 008 was the stormwater discharged from an abandoned
ash pond south of the plant. Ash disposal to this pond was terminated in the late 1970s. A majority of this
area is covered with grass and trees with a small pool of approximately 3 acres of standing water. No
industrial activities are performed in this pond. This pond last discharged in 1998.
Currently, the following outfalls are operational:
Internal Outfall 005
Emergency discharge only.
Outfall 007
This outfall discharges collected flows from the effluent channel consisting of storm water and episodic
emergency flow from Internal Outfall 005. This outfall has not discharged since late 2018.
Outfall 008
This outfall discharges combined flows of treated wastewater from the on -site treatment facility, if
necessary, to assure state Water Quality Standards are not contravened in the receiving stream.
1963/1970 Ash Basins (Outfall 008A). This new outfall is designated as an emergency discharge only.
This is limited to discharging excess wastewater above the available treatment plant capacity during an
eminent threat of 1963/1970 Ash Basin overflow.
1963/1970 Ash Basins (Outfall 008B). This new outfall is designated as an emergency spillway only and
designed to safely pass a design storm event. This Outfall (lat. - 35034'57.37"; long.-79002'57.50")
discharges to Cape Fear River. Sampling of this spillway is waived due to unsafe conditions associated with
sampling during overflow events.
Ash Beneficiation Retention Pond Wastewater (Outfall 009). This new outfall will discharge episodic
wastewater collected from isolated areas of the beneficiation operation consisting of ash storage runoff,
truck loading spills, and dust suppression.
Page 2 of 16

2. Receiving Waterbody Information:
Table 3.
Receiving Stream
Index
7Q10s
(cfs)
QA
(cfs)
IWC
(7Q10s)
Outfall 007 — Unnamed tributary to Cape Fear River
18-(1)
0
0
100%
Outfalls 008 — Cape Fear River
18-(1)
65
3,170
1.7%
Outfall 009 — Cape Fear River
18-(1)
65
3,170
0.012%
Outfall 008A/008B — Cape Fear River
Outfall 005— Internal Outfall
Stream Classification:
WS-IV
Regional Office:
Raleigh
303(d) Listed?:
No
USGS Topo Quad:
E22SE Moncure, NC
I UC No.:
03030002
Permit Writer:
Sergei Chernikov, Ph.D.
Subbasin:
03-06-07
Date:
November 2, 2023
Cape Fear River Stream Statistics
— 2016
Drainage (mi2):
-
Summer — 7Q 10 (cfs):
65 '
Winter — 7Q 10 (cfs):
89,
30Q2 (cfs):
150'
QA (cfs):
3,170'
1. Based on USGS recommendation and data
3. Instream Monitoring
Instream monitoring may be required in certain situations, for example: 1) to verify model predictions
when model results for instream DO are within 1 mg/1 of instream standard at full permitted flow; 2) to
verify model predictions for outfall diffuser; 3) to provide data for future TMDL; 4) based on other
instream concerns. Instream monitoring may be conducted by the Permittee, and there are also
Monitoring Coalitions established in several basins that conduct instream sampling for the Permittee (in
which case instream monitoring is waived in the permit as long as coalition membership is maintained).
If applicable, summarize what instream monitoring will be proposed for this permit action: The current
permit requires instream monitoring for total arsenic, total selenium, total mercury, total chromium,
dissolved lead, dissolved cadmium, dissolved copper, dissolved zinc, total bromide, total hardness (as
CaCO3), temperature, turbidity, and total dissolved solids (TDS) at locations specified in Table 4:
Instream sampling location descriptions are shown in Table 4.
Table 4. Instream Sampling Locations Description
Instream Sample Description
Location
Upstream Outfall 008
0.9 miles upstream from Outfall 008A in Cape Fear River
Approximately 250 meters downstream from Outfall 008 in
Downstream Outfall 008
Cape Fear River
Is this facility a member of a Monitoring Coalition with waived instream monitoring (YIN): Y
Name of Monitoring Coalition: Middle Cape Fear Basin Association
Page 3 of 16

Instream monitoring is provisionally waived considering the permittee's participation in the Middle Cape
Fear River Basin Association provided the Association agrees to sample for all the parameters listed in this
condition and at the specified locations. Instream monitoring shall be conducted as stated in this permit
should the permittee end its participation in the Association.
Review of the instream monitoring data indicates that all the monitoring parameters are well below water
quality standards at upstream and downstream monitoring locations.
The permit also requires annual fish tissue monitoring for arsenic, selenium, and mercury. The following
fish species were sampled at two upstream locations and one downstream location: Largemouth Bass,
Spotted Bass, Bluegill, Hybrid Sunfish, Redbreast Sunfish, Redear Sunfish, and Warmouth.
The concentration of arsenic and selenium at all three locations were below EPA screening values.
Between 33% and 50% of individual mercury concentrations in some Bass species were above EPA
screening values at upstream and downstream locations. The fish tissue data indicates that discharge from
this facility has no measurable impact on the instream accumulation of trace elements in fish species.
4. Antidegradation Review (New/Expanding Discharge):
The objective of an antidegradation review is to ensure that a new or increased pollutant loading will not
degrade water quality. Permitting actions for new or expanding discharges require an antidegradation
review in accordance with 15A NCAC 2B.0201. Each applicant for a new/expanding NPDES permit
must document an effort to consider non -discharge alternatives per 15A NCAC 2H.0105(c)(2). In all
cases, existing instream water uses and the level of water quality necessary to protect the existing use is
maintained and protected.
If applicable, describe the results of the antidegradation review, including the Engineering Alternatives
Analysis (EAA) and any water quality modeling results: NA
5. Antibacksliding Review
Sections 402(o)(2) and 303(d)(4) of the CWA and federal regulations at 40 CFR 122.44(1) prohibit
backsliding of effluent limitations in NPDES permits. These provisions require effluent limitations in a
reissued permit to be as stringent as those in the previous permit, with some exceptions where limitations
may be relaxed (e.g., based on new information, increases in production may warrant less stringent TBEL
limits, or WQBELs may be less stringent based on updated RPA or dilution).
Are any effluent limitations less stringent than previous permit (YESINO): NO
If YES, confirm that antibacksliding provisions are not violated: NA
6.Summary of Proposed Permitting Actions:
Outfal l 007
This outfall discharges at the end of the effluent channel and to an unnamed tributary with a "zero" 7Q 10
summer flow, thus, has an IWC=100%. A reasonable potential analysis was not conducted for this outfall
since it has not discharged wastewater since late 2018 and is not expected to discharge in the future.
Page 4 of 16

Therefore, effluent requirements largely remained unchanged since the last renewal. For the list of all
changes, please see page 11 of this Fact Sheet.
Table 5: Outfall 007 — Episodic discharge
Parameter
Monitoring
DMR Monitoring
Basis
Requirements
Frequency
Flow
0.72 MGD DM
Daily
15A NCAC 213 .0505
6.0 < pH < 9.0 S.U.
pH
Continuous
Monthly
15A NCAC 213.0200
monitoring/auto shutoff
TSS
30.0 mg/L MA
Monthly
EPA requirement,
100 m /L DM
40 CFR 423
Oil & Grease
15.0 mg/L MA
Monthly
40 CFR 423
20.0 m /L DM
Total Antimony
5.6 µg/L MA
Monthly
RP to exceed NC WQS and
5.6 /L DM
EPA criteria
Total Arsenic
10.0 µg/L MA
Monthly
RP to exceed NC WQS and
340.0 /L DM
EPA criteria
Total Molybdenum
160 µg/L MA
Monthly
RP to exceed NC WQS and
160 /L DM
EPA criteria
Total Lead
Monitor & Report, /L
Monthly
Pollutant of concern
Total Nickel
25.0 µg/L MA
Monthly
RP to exceed NC WQS and
335.2 /L DM
EPA criteria
Total Selenium
5.0 µg/L MA
Monthly
RP to exceed NC WQS and
56.0 /L DM
EPA criteria
Total Zinc
125.7 µg/L MA
Monthly
RP to exceed NC WQS and
125.7 /L DM
EPA criteria
Total Mercury
12 n /L, annual average
Monthly
Dewatering strategy
Total Cadmium
Monitor & Report, µg/L
Monthly
No RP, predicted value > 50%
of the Allowable Cw
Total Copper
Monitor & Report, µg/L
Monthly
No RP, predicted value > 50%
of the Allowable Cw
Fluoride
Monitor & Report, mg/L
Monthly
No RP, predicted value > 50%
of the Allowable Cw
Sulfates
Monitor & Report, mg/L
Monthly
No RP, predicted value > 50%
of the Allowable Cw
Total Dissolved
Monitor & Report, mg/L
Monthly
No RP, predicted value > 50%
Solids
of the Allowable Cw
Total Thallium
Monitor & Report, µg/L
Monthly
No RP, predicted value > 50%
of the Allowable Cw
Turbidity
Net Turbidity < 50 NTU
Monthly
EPA requirement
Effluent Hardness
Monitor & Report, mg/L
Quarterly
Required to assess dissolved
metal limitations
Chronic Toxicity
90% concentration, P/F
Quarterly
DEQ Toxicity Policy
Nitrate/Nitrite as N
Monitor & Report, m /L
Quarterly
Needed to calculate TN
Total Kjeldahl
Monitor & Report, mg/L
Quarterly
Needed to calculate TN
Nitrogen
Total Nitrogen
Monitor & Report, m /L
Quarterly
15A NCAC 02B .0500
Total Phosphorus
Monitor & Report, m /L
Quarterly
15A NCAC 02B .0500
MGD — Million gallons per day, MA — Monthly Average, DM — Daily Max
Page 5 of 16

Outfall 008 - Dewatering
Dewatering at this outfall was initiated on 11/11/2019. This outfall will discharge to a segment of the Cape
Fear River and based on stream flow data has a 7Q10 summer -based IWC = 1.7%. A reasonable potential
analysis was conducted using the 0.72 MGD capacity of the treatment system as the estimated flow and
using the highest 1985 (East) and 1978 (West) Ash Basins interstitial water concentration data collected in
January 2015. Based on this analysis, the following permitting actions are proposed for this permit:
• Effluent Limit with Monitoring. The following parameters will receive a water quality -based
effluent limit (WQBEL) since they demonstrated a reasonable potential to exceed applicable
water quality standards/criteria: None
• Monitoring Only. The following parameters will receive a monitor -only requirement since they
did not demonstrate reasonable potential to exceed applicable water quality standards/criteria,
but the maximum predicted concentration was >50% of the allowable concentration: Selenium.
Arsenic and Mercury will be monitored in accordance with the dewatering s trateg3L
No Limit or Monitoring: The following parameters will not receive a limit or monitoring, since
they did not demonstrate reasonable potential to exceed applicable water quality
standards/criteria and the maximum predicted concentration was <50% of the allowable
concentration: Chromium III, Chromium VI, Total Chromium, Beryllium, Total Phenolic
Compounds, Copper, Cyanide, Fluoride, Lead, Nickel, Silver, Zinc, Aluminum, Thallium, and
Sulfate.
Table 6: Outfall 008 - Ash Basin Dewatering
Monitoring
DMR
Parameter
Requirements
Monitoring
Basis
Frequency
Flow
0.72 MGD DM
Dail y
Dewatering strategy,
15A NCAC 2B .0505
6.0 < pH < 9.0 S.U.
Dewatering strategy,
pH
Continuous
Weekly
15A NCAC 2B
monitoring/auto /auto shutoff
.0200
30.0 mg/L MA
Dewatering strategy,
TSS
100 mg/L DM
Weekly
EPA requirement,
Continuous
40 CFR 423
monitoring/auto shutoff
Oil & Grease
15.0 mg/L MA
Weekly
Dewatering strategy,
20.0 m /L DM
40 CFR 423
Total Arsenic
Monitor & Report, /L
Monthly
Dewatering strategy
Total Mercury
Monitor & Report, n /L
Monthly
Dewaterin Strategy
Total Selenium
Monitor & Report, µg/L
Monthly
No RP, predicted Cw > 50%
of Allowable Cw
Turbidity
Net Turbidity < 50 NTU
Weekly
Dewatering strategy
Effluent Hardness
Monitor & Report, mg/L
Quarterly
Required to assess dissolved
metal limitations
Chronic Toxicity
1.7% concentration, P/F
Monthly
Dewatering strategy, DEQ
Toxicity Policy
Nitrate/Nitrite as N
Monitor & Report, m /L
Quarterly
Needed to calculate TN
Total Keldahl Nitrogen
Monitor & Report, m /L
Quarterly
Needed to calculate TN
Page 6 of 16

Total Nitrogen
Monitor & Report, mg/L
Quarterly
15A NCAC 02B .0500
Total Phosphorus
Monitor & Report, mg/L
Quarterly
15A NCAC 02B .0500
MGD — Million gallons per day, MA — Monthly Average, DM — Daily Max
Outfall 008 — Dewatering/Ground Water Remediation
As requested by the Permittee this new outfall will discharge to a segment of the Cape Fear River, and
based on stream flow data and a maximum 0.72 MGD treatment system capacity has a 7Q 10 summer -based
IWC = 1.7%. A reasonable potential analysis was conducted during the last renewal using the 1.7% and
using two source data points if available, one data point from the highest 1985 (East) and 1978 (West) Ash
Basins interstitial water concentration data collected in January 2015 and a second data point from the
highest ground water monitoring wells data collected in 2015 and 2016. Based on this analysis, the
following permitting actions are proposed for this permit:
• Effluent Limit with Monitoring. The following parameters will receive a water quality -based
effluent limit (WQBEL) since they demonstrated a reasonable potential to exceed applicable
water quality standards/criteria: TDS, Aluminum, Copper, Lead, Nickel, Selenium, Silver,
Sulfates, Zinc
Arsenic and Mercury will be monitored in accordance with the dewatering strategy.
• Monitoring Only. The following parameters will receive a monitor -only requirement since they
did not demonstrate reasonable potential to exceed applicable water quality standards/criteria,
but the maximum predicted concentration was >50% of the allowable concentration: Beryllium,
Copper, Cadmium.
No Limit or Monitoring: The following parameters will not receive a limit or monitoring, since
they did not demonstrate reasonable potential to exceed applicable water quality
standards/criteria and the maximum predicted concentration was <50% of the allowable
concentration: Antimony, Chlorides, Chromium III, Chromium VI, Total Chromium, Fluoride,
Barium, Thallium
The Permittee shall notify the Raleigh Regional Office and the Division seven (7) calendar days prior to
the introduction of remediation ground water with the dewatering wastewater.
Table 7: Outfall 008 - Ash Basin Dewatering/Ground Water Remediation
DMR
Parameter
Monitoring Requirements
Monitoring
Basis
Frequency
Flow
0.72 MGD DM
Daily
Dewatering strategy,
15A NCAC 213 .0505
Temperature, °C
Monitor & Report
Weekly
Ground Water Remediation
NCG510000
6.0 < pH < 9.0 S.U.
Dewatering strategy,
pH
Continuous monitoring/auto
Weekly
15A NCAC 213
shutoff
.0200
30.0 mg/L MA
Dewatering strategy,
TSS
100 mg/L DM
Weekly
EPA requirement,
Continuous monitoring/auto
40 CFR 423
shutoff
Oil & Grease
15.0 mg/L MA
Weekly
Dewatering strategy,
20.0 mg/L DM
40 CFR 423
Total Aluminum
385.1 mg/L MA
Monthly
RP to exceed NC WQS and
385.1 mg/L DM
EPA criteria
Total Arsenic
Monitor & Report, µg/L
Monthly
Dewatering strategy,
Page 7 of 16

EPA requirement
Total Beryllium
Monitor & Report, µg/L
Monthly
No RP, predicted Cw > 50% of
Allowable Cw
Total Cadmium
Monitor & Report, µg/L
Monthly
No RP, predicted Cw > 50% of
Allowable Cw
Total Copper
Monitor & Report, µg/L
Monthly
No RP, predicted Cw > 50% of
Allowable Cw
Total Lead
Monitor & Report, µg/L
Monthly
No RP, predicted Cw > 50% of
Allowable Cw
Total Mercury
Monitor & Report, n L
Monthly
Dewatering strategy
Total Nickel
1.48 mg/L MA
Monthly
RP to exceed NC WQS and
16.3 mg/L DM
EPA criteria
Total Selenium
0.30 mg/L MA
Monthly
RP to exceed NC WQS and
2.73 mg/L DM
EPA criteria
Total Silver
Monitor & Report, µg/L
Monthly
No RP, predicted Cw > 50% of
Allowable Cw
Total Zinc
Monitor & Report, µg/L
Monthly
No RP, predicted Cw > 50% of
Allowable Cw
TDS
Monitor & Report, mg/L
Weekly
No RP, predicted Cw > 50% of
Allowable Cw
Sulfates
Monitor & Report, mg/L
Monthly
No RP, predicted Cw > 50% of
Allowable Cw
Turbidity
Net Turbidity < 50 NTU
Weekly
Dewatering strategy,
EPA requirement
Effluent Hardness
Monitor & Report, mg/L
Quarterly
Required to assess dissolved
metal limitations
Chronic Toxicity
1.7% concentration, P/F
Monthly
Dewatering strategy, DEQ
Toxicity Policy
Conductivity, µmhos/cm
Monitor and Report
Quarterly
Ground Water Remediation,
NCG510000
Nitrate/Nitrite as N
Monitor & Report, mg/L
Quarterly
Needed to calculate TN
Total Keldahl Nitrogen
Monitor & Report, mg/L
Quarterly
Needed to calculate TN
Total Nitrogen
Monitor & Report, mg/L
Quarterly
15A NCAC 02B .0500
Total Phosphorus
Monitor & Report, mg/L
Quarterly
15A NCAC 02B .0500
MGD — Million gallons per day, MA — Monthly Average, DM — Daily Max
In addition, a special condition will be added to require the Permittee to submit EPA Form 2C to update the
ground water remediation characterization 180 days after its initial introduction to the treatment system.
The Division may reopen the permit to assign additional limits or conditions.
Outfall 008 — Ground Water Remediation
As requested by the Permittee this new outfall will discharge to a segment of the Cape Fear River, and
based on stream flow data and a maximum 0.72 MGD treatment system capacity has a 7Q 10 summer -based
IWC = 1.7%. The reasonable potential analysis was conducted during the last renewal using only the
highest ground water monitoring wells data toxicant concentration collected in 2015 and 2016 yielded the
same results as the reasonable potential analysis conducted for comingled dewatering and groundwater
remediation waste sources. Therefore, the only changes will be the removal of conditions related to
dewatering activity, and a reduction in various parameters monitoring frequency and TSS limits to comply
with Division ground water remediation permitting strategy.
The Permittee shall notify the Raleigh Regional Office and the Division seven (7) calendar days prior to
the completion of dewatering activities and the continuation of remediation ground water treatment.
Page 8 of 16

Table 8: Outfall 008 - Ground Water Remediation
Monitoring
DMR
Parameter
Requirements
Monitoring
Basis
Frequency
Flow
0.72 MGD DM
Weekly
15A NCAC 2B .0400 et
seq., 02B .0500 et seq.
Temperature, ° C
Monitor &Report
Weekly
Ground Water Remediation,
NCG510000
H
6.0 < H < 9.0 S.U.
Weekly
15A NCAC 2B .0200
TSS
30.0 mg/L MA
Weekly
Ground Water Remediation,
45.0 m /L DM
NCG510000
Oil & Grease
15.0 mg/L MA
Weekly
40 CFR 423
20.0 m /L DM
Total Aluminum
385.1 mg/L MA
2/Month
RP to exceed NC WQS and
385.1 m /L DM
EPA criteria
Total Arsenic
Monitor & Report, µg/L
2/Month
No RP, predicted Cw > 50%
of Allowable Cw
Total Beryllium
Monitor & Report, µg/L
2/Month
No RP, predicted Cw > 50%
of Allowable Cw
Total Lead
Monitor & Report, µg/L
2/Month
No RP, predicted Cw > 50%
of Allowable Cw
Total Mercury
Monitor & Report, µg/L
2/Month
No RP, predicted Cw > 50%
of Allowable Cw
Total Nickel
1.48 mg/L MA
2/Month
RP to exceed NC WQS and
16.3 m /L DM
EPA criteria
Total Selenium
Monitor & Report, µg/L
2/Month
No RP, predicted Cw > 50%
of Allowable Cw
Total Silver
Monitor & Report, µg/L
2/Month
No RP, predicted Cw > 50%
of Allowable Cw
Total Zinc
Monitor & Report, µg/L
2/Month
No RP, predicted Cw > 50%
of Allowable Cw
TDS
Monitor & Report, mg/L
2/Month
No RP, predicted Cw > 50%
of Allowable Cw
Sulfates
14,811 mg/L MA
2/Month
RP to exceed NC WQS and
14,811m /L DM
EPA criteria
Turbidity
Net Turbidi < 50 NTU
2/Month
15 NCAC 2B .0500
Effluent Hardness
Monitor & Report, mg/L
Quarterly
Required to assess dissolved
metal limitations
Chronic Toxicity
1.7% concentration, P/F
Quarterly
Dewatering strategy, DEQ
Toxicity Policy
Conductivity, µmhos/cm
Monitor and Report
Quarterly
Ground Water Remediation,
NCG510000
Nitrate/Nitrite as N
Monitor & Report, m /L
Quarterly
Needed to calculate TN
Total Keldahl Nitrogen
Monitor & Report, m /L
Quarterly
Needed to calculate TN
Total Nitrogen
Monitor & Report, m /L
Quarterly
15A NCAC 02B .0500
Total Phosphorus
Monitor & Report, m /L
Quarterly
15A NCAC 02B .0500
MGD — Million gallons per day, MA — Monthly Average, DM — Daily Max
Outfall 008A — 1963/1970 Ash Basins Emergency Outfall
Page 9 of 16

This new outfall is designated as an emergency discharge only. This is limited to discharging excess
wastewater above the available treatment plant capacity during an eminent threat of 1963/1970 Ash Basin
overflow.
Table 9: Outfall 008A - 1963/1970 Ash Basins Emeraencv
Parameter
Monitoring
DMR Monitoring Frequency
Basis
Re uirements
Monitor and report
Daily during Episodic Event
NCAC 2B et
15AFlow
seeq.q. et se, 02B .0500 et seq.
H
6.0 < H < 9.0 S.U.
Daily during Episodic Event
15A NCAC 2B .0200
TSS
30.0 mg/L MA
Daily during Episodic Event
Ground Water Remediation,
100.0 m /L DM
NCG510000
Oil & Grease
15.0 mg/L MA
Daily during Episodic Event
40 CFR 423
20.0 m /L DM
Outfall 009 — Beneficiation Miscellaneous Wastewater
As requested by the Permittee this new outfall will discharge to a segment of the Cape Fear River, and
based on stream flow data and a maximum 0.005 MGD discharge has a 7Q10 summer -based IWC =
0.012%. The expected sources of wastewater from the Beneficiation process area are ash pile run off, truck
washing and ash dust spills. Data from an existing similar operation which included 21 toxicants was
provided to characterize the proposed Beneficiation waste stream, and used to conduct a reasonable
potential analysis during the last renewal.
No Limit or Monitoring: The following parameters will not receive a limit or monitoring, since they
did not demonstrate reasonable potential to exceed applicable water quality standards/criteria and the
maximum predicted concentration was <50% of the allowable concentration: Aluminum, Antimony,
Cadmium, Chlorides, Barium, Beryllium, Total Chromium, Copper, Fluoride, Lead, Molybdenum,
Nickel, Silver, Thallium, Zinc, Sulfates, TDS
Monitoring for Arsenic and Selenium will be required as they are toxicants of concern.
Table 10: Outfall 009 — Beneficiation Miscellaneous Wastewater
Parameter
Monitoring
DMR Monitoring
Requirements
FrequencyBasis
Flow
0.005 MGD DM
Weekly
15A NCAC 2B .0400 et
seq., 02B .0500 et seq.
Temperature, °C
Monitor & Report
Monthly
BPJ (untreated waste
stream)
H
6.0 < H < 9.0 S.U.
Monthly
15A NCAC 2B .0200
TSS
30.0 mg/L MA
Monthly
BPJ (untreated waste
100.0 m /L DM
stream)
Oil & Grease
15.0 mg/L MA
Monthly
40 CFR 423
20.0 m /L DM
Total Mercury
47 n /L, annual average
Monthly
Mercury TMDL
Total Arsenic
Monitor & Report
Monthly
Toxicant of concern, BPJ
(coal ash source)
Total Selenium
Monitor & Report
Monthly
Toxicant of concern, BPJ
(coal ash source)
Turbidity
Net Turbidi < 50 NTU
Monthly
15 NCAC 2B .0500
MGD — Million gallons per day, MA — Monthly Average, DM — Daily Max
Page 10 of 16

Internal Outfall 005- Ash Basins Emergency Overflow Discharge
As requested by the Permittee internal outfall will be permitted for an existing 1985 (East) Ash Basin to
address potential emergency overflow only events.
An emergency discharge is defined as the ash basin wastewater that is in excess of the facility 0.72 MGD
treatment capacity that will overflow.
Table 11: Ash Basin Emergency Overflow Outfall 005
Parameter
Monitoring
Sample
Requirements 2
Type
Flow
Monitor & Report, MGD
Estimate
Outfall 005 (Internal)
Monitor & Report Outfall 007 per A. (3.) 3
Notes
1. The Permittee shall notify the Raleigh Regional Office (919) 791 — 4200 no later than the
end of the next business day of the occurrence of an emergency discharge event including
time of occurrence, duration, and cause.
2. During the duration of a discharge event, the flow shall be reported daily.
3. Effluent monitoring shall commence immediately at the impacted external outfall (Outfall
007) for the limited parameters except for Mercury and Chronic Toxicity. Monitoring
parameters will continue weekly during the emergency discharge event. Any external
outfall's monitoring requirements in effect prior to an emergency discharge shall remain in
effect.
Summary of Proposed Changes
1. The description of wastewater types discharged from Outfall 007 was updated to reflect
the current operational status.
2. The Internal Outfall 001 was removed from the permit because this outfall was eliminated.
3. The S-05 Outfall was removed from the permit based upon this former seep being
dispositioned in accordance with consent order EMC SOC WQ 19-001 and coverage in the
Seep Corrective Action Plan.
4. The Division is unable to eliminate Selenium limits for Outfall 007 since this Outfall has
not discharged since late 2018 and the RPA cannot be conducted.
5. The monitoring frequency for Arsenic, Selenium, and Mercury was reduced from weekly
to monthly based on the review of the effluent data and frequency of discharge.
6. The Division is unable to eliminate the WET testing requirements for Outfall 007 to be
consisted with the requirements of 15A NCAC 213 .0500.
7. The requirements associated with decanting and dewatering have been removed from
Outfall 007 because decanting has been completed and dewatering discharge is routed
through Outfall 008.
8. The Effluent page for Outfall 008 decanting was eliminated from the permit since this
activity has been completed and dewatering was initiated on 11/11/2019.
Page 11 of 16

9. The limits for Selenium have been removed from the permit based on the results of the
RPA (Outfall 008 dewatering).
10. The monitoring frequency for Arsenic, Selenium, and Mercury was reduced from weekly
to monthly based on the results of the RPA (Outfall 008 dewatering).
11. The monitoring requirements for Aluminum, Nickel, Lead, and Cadmium were eliminated
from the permit based on the results of the RPA (Outfall 008 dewatering).
12. The limits and monitoring requirements for Copper were eliminated from the permit based
on the results of the RPA (Outfall 008 dewatering).
13. The Division is unable to reduce frequency of the WET testing requirements for Outfall
008 until dewatering is complete to be consistent with the Division's dewatering strategy.
14. The Division is unable to eliminate requirements associated with dewatering from Outfall
008 until dewatering is completed.
15. The Division is unable to eliminate Selenium limits for Outfall 008 (dewatering and
groundwater remediation) since this phase of the operation has not been initiated and the
RPA cannot be conducted.
16. The monitoring frequency for Arsenic, Selenium, Mercury, Aluminum, Nickel, Beryllium,
Copper, Lead, Silver, and Zinc was reduced from weekly to monthly based on the results
of the RPA (Outfall 008 dewatering and groundwater remediation).
17. The monitoring frequency for instream monitoring was reduced from Monthly to Quarterly
based on the review of the instream data.
18. The monitoring frequency for fish tissue instream monitoring was reduced from Annually
to once per permit term based on the review of the fish tissue data.
7. Public Notice Schedule:
Permit to Public Notice: 1/24/2024
Per 15A NCAC 2H .0109 & .0111, The Division will receive comments for a period of 30 days following
the publication date of the public notice. Any request for a public hearing shall be submitted to the
Director within the 30 days comment period indicating the interest of the party filing such request and the
reasons why a hearing is warranted.
Page 12 of 16

NPDES Implementation of Instream Dissolved Metals Standards - Freshwater Standards
The NC 2007-2015 Water Quality Standard (WQS) Triennial Review was approved by the NC
Environmental Management Commission (EMC) on November 13, 2014. The US EPA subsequently
approved the WQS revisions on April 6, 2016, with some exceptions. Therefore, metal limits in draft
permits out to public notice after April 6, 2016 must be calculated to protect the new standards - as
approved.
Table 1. NC Dissolved Metals Water Quality Standards/Aquatic Life Protection
Parameter
Acute FW, µg/1
(Dissolved)
Chronic FW, µg/I
(Dissolved)
Acute SW, µg/1
(Dissolved)
Chronic SW, µg/1
(Dissolved)
Arsenic
340
150
69
36
Beryllium
65
6.5
---
---
Cadmium
Calculation
Calculation
40
8.8
Chromium III
Calculation
Calculation
---
---
Chromium VI
16
11
1100
50
Copper
Calculation
Calculation
4.8
3.1
Lead
Calculation
Calculation
210
8.1
Nickel
Calculation
Calculation
74
8.2
Silver
Calculation
0.06
1.9
0.1
Zinc
Calculation
Calculation
90
81
Table 1 Notes:
1. FW= Freshwater, SW= Saltwater
2. Calculation = Hardness dependent standard
3. Only the aquatic life standards listed above are expressed in dissolved form. Aquatic life
standards for Mercury and selenium are still expressed as Total Recoverable Metals due to
bioaccumulative concerns (as are all human health standards for all metals). It is still necessary
to evaluate total recoverable aquatic life and human health standards listed in 15A NCAC
213.0200 (e.g., arsenic at 10 µg/l for human health protection; cyanide at 5 µg/L and fluoride at
1.8 mg/L for aquatic life protection).
Table 2. Dissolved Freshwater Standards for Hardness -Dependent Metals
The Water Effects Ratio (WER) is equal to one unless determined otherwise under 15A
NCAC 02B .0211 Subparagraph (11)(d)
Metal
NC Dissolved Standard, µg/I
Cadmium, Acute
WER*{1.136672-[ln hardness](0.041838)} ef0.9789 [In hardness]-3.443}
Cadmium, Acute Trout waters
WER*{1.136672-[ln hardness](0.041838)} e lO.9789[ln hardness]-3.866}
Cadmium, Chronic
WER*{1.101672-[ln hardness](0.041838)} - ej0.7977[ln hardness]-3.909}
Chromium III, Acute
WER*0.316 e-10.8190[ln hardness]+3.7256}
Chromium III, Chronic
WER*0.860 e-10.8190[ln hardness]+0.6848}
Copper, Acute
WER*0.960 e-10.9422[ln hardness]-1.7001
Copper, Chronic
WER*0.960 e^{0.8545[ln hardness]-1.7021
Lead, Acute
WER*{1.46203-[ln hardness](0.145712)} • e ll.273[ln hardness]-1.4601
Lead, Chronic
WER*{1.46203-[ln hardness](0.145712)} • of 1.273[ln hardness]-4.705}
Nickel, Acute
WER*0.998 e^{0.8460[ln hardness]+2.255}
Nickel, Chronic
WER*0.997 e^{0.8460[ln hardness]+0.0584}
Page 13 of 16

Silver, Acute
WER*0.85 • e^{1.72[ln hardness]-6.59}
Silver, Chronic
Not applicable
Zinc, Acute
WER*0.978 e^{0.8473[ln hardness]+0.884}
Zinc, Chronic
WER*0.986 e^{0.8473[ln hardness]+0.884}
General Information on the Reasonable Potential Analysis (RPA)
The RPA process itself did not change as the result of the new metals standards. However, application of
the dissolved and hardness -dependent standards requires additional consideration in order to establish the
numeric standard for each metal of concern of each individual discharge.
The hardness -based standards require some knowledge of the effluent and instream (upstream) hardness
and so must be calculated case -by -case for each discharge.
Metals limits must be expressed as `total recoverable' metals in accordance with 40 CFR 122.45(c). The
discharge -specific standards must be converted to the equivalent total values for use in the RPA
calculations. We will generally rely on default translator values developed for each metal (more on that
below), but it is also possible to consider case -specific translators developed in accordance with
established methodology.
RPA Permitting Guidance/WOBELs for Hardness -Dependent Metals - Freshwater
The RPA is designed to predict the maximum likely effluent concentrations for each metal of concern,
based on recent effluent data, and calculate the allowable effluent concentrations, based on applicable
standards and the critical low -flow values for the receiving stream.
If the maximum predicted value is greater than the maximum allowed value (chronic or acute), the
discharge has reasonable potential to exceed the standard, which warrants a permit limit in most cases. If
monitoring for a particular pollutant indicates that the pollutant is not present (i.e. consistently below
detection level), then the Division may remove the monitoring requirement in the reissued permit.
1. To perform a RPA on the Freshwater hardness -dependent metals the Permit Writer compiles the
following information:
• Critical low flow of the receiving stream, 7Q10 (the spreadsheet automatically calculates
the 1 Q 10 using the formula 1 Q 10 = 0.843 (s7Q 10, cfs) 0.993
Effluent hardness and upstream hardness, site -specific data is preferred
Permitted flow
• Receiving stream classification
In order to establish the numeric standard for each hardness -dependent metal of concern and for
each individual discharge, the Permit Writer must first determine what effluent and instream
(upstream) hardness values to use in the equations.
The permit writer reviews DMR's, Effluent Pollutant Scans, and Toxicity Test results for any
hardness data and contacts the Permittee to see if any additional data is available for instream
hardness values, upstream of the discharge.
If no hardness data is available, the permit writer may choose to do an initial evaluation using a
default hardness of 25 mg/L (CaCO3 or (Ca + Mg)). Minimum and maximum limits on the
hardness value used for water quality calculations are 25 mg/L and 400 mg/L, respectively.
Page 14 of 16

If the use of a default hardness value results in a hardness -dependent metal showing reasonable
potential, the permit writer contacts the Permittee and requests 5 site -specific effluent and
upstream hardness samples over a period of one week. The RPA is rerun using the new data.
The overall hardness value used in the water quality calculations is calculated as follows:
Combined Hardness (chronic)
_ (Permitted Flow, cfs *Avg. Effluent Hardness, mg/L)+s7Q10, cfs *Avg. Upstream Hardness, mg/L
(Permitted Flow, cfs + s7Q10, cfs)
The Combined Hardness for acute is the same but the calculation uses the IQ 10 flow.
3. The permit writer converts the numeric standard for each metal of concern to a total recoverable
metal, using the EPA Default Partition Coefficients (DPCs) or site -specific translators, if any
have been developed using federally approved methodology.
EPA default partition coefficients or the 'Traction Dissolved" converts the value for
dissolved metal at laboratory conditions to total recoverable metal at in -stream
ambient conditions. This factor is calculated using the linear partition coefficients
found in The Metals Translator: Guidance for Calculating a Total Recoverable
Permit Limit from a Dissolved Criterion (EPA 823-B-96-007, June 1996) and the
equation:
Cdiss - I
Ctotal I + { [Kpo] [ss(t+a)] [10 6] }
Where:
ss = in -stream suspended solids concentration [mg/1], minimum of 10 mg/L used,
and
Kpo and a = constants that express the equilibrium relationship between dissolved
and adsorbed forms of metals. A list of constants used for each hardness -dependent
metal can also be found in the RPA program under a sheet labeled DPCs.
4. The numeric standard for each metal of concern is divided by the default partition coefficient (or
site -specific translator) to obtain a Total Recoverable Metal at ambient conditions.
In some cases, where an EPA default partition coefficient translator does not exist (le. silver), the
dissolved numeric standard for each metal of concern is divided by the EPA conversion factor to
obtain a Total Recoverable Metal at ambient conditions. This method presumes that the metal is
dissolved to the same extent as it was during EPA's criteria development for metals. For more
information on conversion factors see the June, 1996 EPA Translator Guidance Document.
5. The RPA spreadsheet uses a mass balance equation to determine the total allowable concentration
(permit limits) for each pollutant using the following equation:
Ca = (s7Q10 + Qw) Cwgs) — (s7Q10) (Cb)
Qw
Where: Ca = allowable effluent concentration (µg/L or mg/L)
Cwqs = NC Water Quality Standard or federal criteria (µg/L or mg/L)
Cb = background concentration: assume zero for all toxicants except NH3* (µg/L or mg/L)
Qw = permitted effluent flow (cfs, match s7Q10)
Page 15 of 16

s7Q10 = summer low flow used to protect aquatic life from chronic toxicity and human
health through the consumption of water, fish, and shellfish from noncarcinogens (cfs)
* Discussions are on -going with EPA on how best to address background concentrations
Flows other than s7Q10 may be incorporated as applicable:
1Q10 = used in the equation to protect aquatic life from acute toxicity
QA = used in the equation to protect human health through the consumption of water,
fish, and shellfish from carcinogens
30Q2 = used in the equation to protect aesthetic quality
6. The permit writer enters the most recent 2-3 years of effluent data for each
pollutant of concern. Data entered must have been taken within four and one-
half years prior to the date of the permit application (40 CFR 122.21). The
RPA spreadsheet estimates the 95th percentile upper concentration of each
pollutant. The Predicted Max concentrations are compared to the Total
allowable concentrations to determine if a permit limit is necessary. If the
predicted max exceeds the acute or chronic Total allowable concentrations,
the discharge is considered to show reasonable potential to violate the water
quality standard, and a permit limit (Total allowable concentration) is
included in the permit in accordance with the U.S. EPA Technical
Support Document for Water Quality -Based Toxics Control published in
1991.
7. When appropriate, permit writers develop facility specific compliance schedules in accordance
with the EPA Headquarters Memo dated May 10, 2007 from James Hanlon to Alexis Strauss on
40 CFR 122.47 Compliance Schedule Requirements.
The Total Chromium NC WQS was removed and replaced with trivalent chromium and
hexavalent chromium Water Quality Standards. As a cost savings measure, total chromium data
results may be used as a conservative surrogate in cases where there are no analytical results
based on chromium III or VI. In these cases, the projected maximum concentration (95th %) for
total chromium will be compared against water quality standards for chromium III and
chromium VI.
9. Effluent hardness sampling and instream hardness sampling, upstream of the discharge, are
inserted into all permits with facilities monitoring for hardness -dependent metals to ensure the
accuracy of the permit limits and to build a more robust hardness dataset.
Page 16 of 16