NC0024406_Fact Sheet_20191212

DEQ/DWR
FACT SHEET FOR NPDES PERMIT DEVELOPMENT
Minor Modification
NPDES No. NCO024406
Facility Information
Applicant/Facility
Name:
Duke Energy Carolinas, LLC- Belews Creek Steam Station
Applicant Address:
13339 Hagers Ferry Road; Huntersville, North Carolina 2807
Facility Address:
3195 Pine Hall Road; Belews Creek, NC 27009
Permitted Flow
N/A
Type of Waste:
Industrial (- 100%); Domestic (< 1%)
Prim.SIC Code: 4911
Facility/Permit
Status:
Class I /Active; Renewal
County:
I Stokes County
Miscellaneous
Receiving Stream:
Belews Lake (001,
005, 007), UT to
Dan River (003,
003A) , Dan River
006
Regional Office:
Winston-Salem
(WSRO)
Stream
Classification:
C (Belews Lake),
WS-IV (Dan River
and UT to Dan
River)
State Grid / USGS
Quad:
1318SE/Belews
Lake
303(d) Listed?
No
Permit Writer:
Sergei Chernikov,
Ph.D.
Subbasin:
03-02-01
Date:
10/29/2018
Drainage Area (mi2):
501 (Dan River)
001: Lat. 36° 16' 49.5" N
003: Lat. 36° 18' 22.0" N
006: Lat. 36° 18' 34.8" N
Long. 80' 03' 39.8" W
Long. 80' 04' 50.7" W
Long. 80° 04' 36.1" W
Summer 7Q 10 (cfs)
80 (Dan River)
Winter 7Q 10 (cfs):
160 (Dan River)
30Q2 (cfs)
195 (Dan River)
Average Flow (cfs):
576 (Dan River)
IWC (%):
26.5
BACKGROUND
Duke Energy's Belews Creek Steam Station is a coal fired steam electric plant in Stokes
County. The facility is subject to the federal effluent guidelines 40 CFR Part 423.
In addition to NPDES Permit NC0024406, the facility also holds the following permits:
01983R12 (air permit), NCD000856591 (Hazardous wastes), and 85-03 (industrial
landfill).
Duke Energy requested a Modification to the permit that allows the ash basin decanting
flow to be released through Internal Outfall 006A/External Outfall 006. The request has
been granted.
A new RPA has been conducted based on the projected maximum decanting flow of 5.5
MGD. Based on the results of the RPA, Daily maximum and Monthly average limits for
lead have been reduced (Outfall 006A). The Supplement to Permit Cover Sheet and
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Condition A. (4.) have also been amended to allow decanting flow to be released through
Internal Outfall 006A.
All remaining terms and conditions of the permit remain unchanged.
The facility operates the following outfalls:
• Outfall 001: once through cooling water consisting of intake screen
backwash, recirculating cooling water, station equipment cooling water and
once -through cooling water, this Outfall discharges to Belews Lake.
• Outfall 003: ash basin discharge consisting of waste streams from the power
house and yard holding sumps, ash sluice lines, chemical holding pond,
coal yard sumps, stormwater, coal pile collection basins (collecting contact
stormwater from coal piles), remediated groundwater, emergency release of
anhydrous ammonia, seepage from coal ash basin, emergency overflow from
the retention basin, emergency overflows from the existing effluent channels,
and treated FGD wastewater from internal outfall 002. The wastewater from
this outfall discharges to Unnamed Tributary (UT) to Dan River.
Internal outfall 002: FGD wastewater (discharging to ash pond)
• Outfall 003A/006. Upon completion of construction, discharge from the new
lined retention basin. Basin will accept wastes from holding basin, ash
contact water, various sumps, coal pile runoff, stormwater runoff, cooling
tower blowdown, FGD wastewater, and various low volume wastes such as
boiler blowdown, oily waste treatment, wastes/backwash from the water
treatment processes, coal pile collection basins (collecting contact
stormwater from coal piles), plant area wash down water, cooling tower
blowdown, equipment heat exchanger water, remediated groundwater,
emergency overflow (rain in excess of designed storm event), toe drain
(potential discharge to outfall 006 only), emergency release of anhydrous
ammonia, release of ammonia during quarterly testing, and treated domestic
wastewater. Outfall 003A discharges to UT to Dan River via the Outfall 003.
Upon completion of construction all waste streams previously discharged to
ash basin, will be re-routed to the new retention basin. During the transition
period, wastewater from the ash pond can also be discharged from Outfall
003. Construction of new Outfall 006 has been completed. Outfall 006 will
discharge to Dan River. This Outfall will be used for decanting and
dewatering of the ash basin.
• Outfall 005. This is a former stormwater outfall SW002, consists of once
through non -contact chiller water and stormwater. The wastewater from this
outfall discharges to Belews Lake.
• Internal Outfall 006A. This is a temporary internal outfall for decanting and
dewatering of the ash basin, it will discharge through new Outfall 006.
• Outfall 007 (lat. - 36016'51.604"; long. 80003'52.995"). This is an emergency
spillway for South Coal Basin. This outfall discharges to Belews Lake. The
spillway is designed for a flood greater than 100-year event. Sampling of this
spillway is waived due to unsafe conditions associated with sampling during
overflow event.
• Internal outfall 009. Domestic wastewater plant. The wastewater from this
outfall discharges to UT to Dan River via Outfall 003 or to Dan River via
Outfall 006.
• Toe Drain Outfall 111 (lat. - 36017'54.94"; long. - 80.04'32.57")- potentially
contaminated toe drain. This outfall discharges to UT to Dan River.
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PROPOSED CHANGES
• Internal Outfall 006A now allows discharge of the wastewater from the
decanting procedure.
• The Water Quality Based Effluent Limits (Monthly Average and Daily Maximum)
for Total Lead have been reduced (Internal Outfall 006A) due to the increase in
the flow through this Outfall. The projected decanting flow is 5.5 MGD.
PROPOSED SCHEDULE
Draft Permit Modification to Public Notice: August 21, 2019
Permit Modification Scheduled to Issue: October 18, 2019
STATE CONTACT
If you have any questions on any of the above information or on the attached permit,
please contact Sergei Chernikov at [phone] or [e-mail].
RESPONSE TO THE SELL COMMENTS
Delete Outfall 003
The facility requested a Major Modification to the permit that allows decanting through
the Outfall 006/006A. This modification only applies to this narrow aspect of the
permit, the DEQ is not re -opening the entire permit. The permit expiration date does
not change and it will be re -opened during the next renewal period when all aspect of
the permit will be reviewed and reconsidered.
The facility might need to use Outfall 003 before the ash pond closure is completed.
Duke Energy must treat all, not iust a small portion, of its contaminated decanting
wastewater
The facility requested a Major Modification to the permit that allows decanting through
the Outfall 006/006A. This modification only applies to this narrow aspect of the
permit, the DEQ is not re -opening the entire permit. The permit expiration date does
not change and it will be re -opened during the next renewal period when all aspect of
the permit will be reviewed and reconsidered.
The DEQ assigns the appropriate permit limits based on the Reasonable Potential
Analysis or 40 CFR 423 requirements. The facility has the ability to choose the
mechanism to achieve the compliance with these limits. In the past the DEQ had an
authority to issue Authorization to Construct permits, which in effect prescribed a
treatment method for a particular wastewater. However, the state legislature has
removed this authority from DEQ and now the Department cannot issue ATC permits
for industrial facilities (Session Law 2011-394).
The Outfall 006A permit limits violate the Clean Water Act
The facility requested a Major Modification to the permit that allows decanting through
the Outfall 006/006A. This modification only applies to this narrow aspect of the
permit, the DEQ is not re -opening the entire permit. The permit expiration date does
not change and it will be re -opened during the next renewal period when all aspect of
the permit will be reviewed and reconsidered.
The need for water quality based effluent permit limits is determined based on the
results of the reasonable potential analysis (RPA). The RPA procedure utilized by the
Division is conducted in accordance with the EPA's regulation (40 CFR 122.44(d)(1)).
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When the permitting authority determines, using procedures in paragraph (d) (1) (ii) of
this section, that a discharge causes, has the reasonable potential to cause, or
contributes to an in -stream excursion above the allowable ambient concentration of a
State numeric criteria within a State water quality standard for an individual
pollutant, the permit must contain effluent limits for that pollutant. Permit limits are
added only if the results of the RPA indicate the potential for exceeding the water
quality standards, and are not arbitrarily assigned. However, absence of permit limits
does not allow the facility to violate instream water quality standards.
Increased Monitoring at Outfall 002
The facility requested a Major Modification to the permit that allows decanting through
the Outfall 006/006A. This modification only applies to this narrow aspect of the
permit, the DEQ is not re -opening the entire permit. The permit expiration date does
not change and it will be re -opened during the next renewal period when all aspect of
the permit will be reviewed and reconsidered.
Outfall 002 is an internal outfall it does not directly discharge to the Waters of the
State. Wastewater from this Outfall undergoes an additional treatment at the Lined
Retention Basin and then discharged to Dan River through Outfall 006. Frequency of
monitoring at Outfall 006 and number of parameters that are being monitored are
based on results of the reasonable potential analysis (RPA) and requirements
contained in Federal and State rules and regulations. If a parameter shows reasonable
potential and requires a limit, monitoring is generally at a monthly or quarterly
frequency. If a parameter does not show reasonable potential, monitoring might not
be required. Monthly discharge monitoring reports (DMRs) and priority pollutant
scans (required with each permit renewal) are evaluated for RPA with each renewal.
The proposed monitoring frequencies will provide adequate information to conduct
RPA for the next permit renewal. The Division has a long term monitoring data for
coal-fired facilities' discharges and accumulated a statistically significant dataset for
all typical pollutants associated with the coal ash. This data set allows for an accurate
characterization of the discharge from ash ponds at the frequency prescribed in the
permit. In addition, Duke submitted chemical characterization of the wastewater in
ash lagoons that demonstrates little variation in the pollutant concentration at the
different depth levels. Therefore, additional monitoring is not likely to provide any
additional useful information.
Flow limit at Outfall 006A
The facility requested a Major Modification to the permit that allows decanting through
the Outfall 006/006A. This modification only applies to this narrow aspect of the
permit, the DEQ is not re -opening the entire permit. The permit expiration date does
not change and it will be re -opened during the next renewal period when all aspect of
the permit will be reviewed and reconsidered.
The flow limit for decanting for Outfall 003 was included in the permit to provide an
additional protection for a zero -flow stream. Outfall 006/006A discharges to Dan River
with a substantial dilution. Adding a flow limit to this Outfall can delay decanting
beyond SOC and statutory deadlines due to the high stormwater inputs.
In addition, a Reasonable Potential Analysis for this flow was based on the projected
decanting volume of 5.5 MGD and appropriate limits have been implemented to
protect Dan River. Therefore, a flow limit for Outfall 006/006A is unnecessary.
Outfall 009 and Outfall III
The facility requested a Major Modification to the permit that allows decanting through
the Outfall 006/006A. This modification only applies to this narrow aspect of the
Page 4 of 5

permit, the DEQ is not re -opening the entire permit. The permit expiration date does
not change and it will be re -opened during the next renewal period when all aspect of
the permit will be reviewed and reconsidered.
Both Outfalls will continue discharges in the near future and will remain in the permit
until next renewal or Major Modification.
Page 5 of 5