NC0004961_Error Correction Letter 12/6/16_20161206

s
WaterResources
ENVIRONMENTAL QUALITY
December 6, 2016
Mr. Harry Sideris, Senior Vice President
Environmental, Health and Safety
Duke Energy Carolinas, LLC
Mail Code EC13K
P.O. Box 1006
Charlotte, North Carolina 28201-1006
Dear Mr. Sideris:
PAT MCCRORY
Governor
DONALD R. VAN DER VAART
Secretary
S. JAY ZIMMERMAN
Director
RECEIVEMCpk iLOV-
DEC 15 2016
Water Quality
Permitting Section
Subject: Error Correction Letter
and final permit issuance
Permit No. NC0004961
Riverbend Steam Station
Gaston County
On February 12, 2016, the Division of Water Resources issued NPDES Permit No.
NC0004961 for Riverbend Steam Station. It has been brought to our attention that the
Permit has inconsistent monitoring frequency for the Whole Effluent Toxicity testing.
The correct monitoring frequency shall be Monthly.
Therefore, the Division made a correction to the appropriate pages in the NPDES
Permit. Please insert the enclosed corrected sheets and discard the old sheets. This
permit modification becomes effective on the effective date of the permit.
All other terms and conditions in the original permit remain unchanged and in full
effect. These modifications are issued pursuant to the requirements of North Carolina
General Statute 143-215.1 and the Memorandum of Agreement between North Carolina
and the U.S. Environmental Protection Agency dated December 6, 1983.
In addition, due to the withdrawal of the contested case by Duke Energy, the effective
date of the permit shall be December 1, 2016.
If any parts, measurement frequencies or sampling requirements contained in this
modification are unacceptable to you, you have the right to an adjudicatory hearing
upon written request within thirty (30) days following receipt of this letter. This request
must be in the form of a written petition, conforming to Chapter 150B of the North
Carolina General Statutes, and filed with the Office of Administrative Hearings, Post
Office Drawer 11666, Raleigh, North Carolina 27604. Unless such demand is made,
State of North Carolina I Environmental Quality I Water Resources
1617 Mail service Center I Raleigh, North Carolina 27699-1611
919 707 9000 '

this decision shall be final and binding. If you have any questions concerning this
permit, please contact Sergei Chernikov at telephone number [phone].
Sincerely,
S. Jay Zimmerman, P.G.
.ro Director, Division of Water Resources
Hardcopy: Central Files
NPDES Files
Mooresville Regional Office
E -copy: US EPA, Region IV
Aquatic Toxicology Unit
Carrie Ruhhnan, WSS
s

Permit NC0004961
A. (2.) EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS (Outfall
002 -normal operation) 115A NCAC 02B .0400 et seq., 02B .0500 et seq.)
During the period beginning on the effective date of this permit and lasting until expiration, the
Permittee is authorized to discharge from outfall 002 - Ash Pond Discharge (removing the free
water above the settled ash layer that does not involve mechanical movement of the ash).
Such discharges shall he limited anti mnnitnrerl6 by the PPrmjttPp ac er%Pr IfIAA 1_1_xr.
EFFLUENT
CHARACTERISTICS
Monthly
Average
LIMITS
Daily
Maximum
MONITORING REQUIREMENTS
Sample Type Sample Location
%��uen]
Flow
5 74 MGD
Daily
Pump logs or
estimate
Influent or Effluent
Total Suspended Solids8
23 0 m L
75 0 m IL
Weekly
Grab
Effluent
Oil and Grease
110 m /L
15 0 m /L
Weekly
Grab
Effluent
Total Copper'
10 m /L
10 m /L
Weekly
Grab
Effluent
Total Iron'
1 Orn /L
10 m /L
Weekly
Grab
Effluent
Total Arsenic
52 5 /L
72.5 /L
Weekly
Grab
Effluent
Total Selenium
68.0 /L
127 5 L
Weekly
Grab
Effluent
Nitrate/rntnte as N
0 65 m /L
0 85 m
Weekly
Grab
Effluent
Total Arsenic
10 5 V
14 5 7
Weekly
Grab
Effluent
Total Selenium
13.6 /L7
25.5 /L7
Weekly
Grab
Effluent
Total Mercury
47 0 ng/L5
47 0 ng/L5
Weekly
Grab
Effluent
Nitrate/nitrite as N
0.13 mg/L7
017 mg/L7
Weekly
Grab
Effluent
Total Phosphorus, m /L
Weekly
Grab
Effluent
Total Nitrogen (NO2 + NO3 + TKN),
m /L
Weekly
Grab
Effluent
Fie
Weekly
Grab
Effluent
Chronic To)dC4ty3
Monthly
Grab
Effluent
Turbidity4,NTU
Weekly
Grab
Effluent
Total Chromium, /L
Weekly
Grab
Effluent
Total Cadmium, /L
Weekl
Grab
Effluent
Total Lead, /L
Weekly
Grab
Effluent
TDS, m L
WeeklEyl
Grab
Effluent
notes:
1 The limits for total copper and total iron only apply when chemical metal cleaning wastewaters
are being discharged.
2. The pH shall not be less than 6.0 standard units nor greater than 9.0 standard units. The facility
shall conduct a real time pH monitoring with an auto shut-off if the 15 -minute running average
pH falls below, 6.1 standard units or nses above 8.9 standard units.
3. Whole Effluent Toxicity shall be monitored by chronic toxicity (Cenodaphnia) P/1~ at 2.7%, see
Part A. (5 ) for details.
4. The discharge from this facility shall not cause turbidity in the receiving stream to exceed 50
NTU. If the instream turbidity exceeds 50 NTU due to natural background conditions, the
discharge cannot cause turbidity to increase in the receiving stream
NTU - Nephelometric Turbidity Unit.
5 The facility shall use EPA method 1631E.
6 No later than 270 days from the effective date of this permit, begin submitting discharge
monitoring reports electronically using NC DWR's eDMR application system See Special
Condition A. (18.).
7 The TBEL limits shall be met no later than'December 31, 2019 This time period is provided
in order, for the facility to budget, design, and construct the treatment system. Permit might
be re -opened to implement the ,final EPA Effluent Guidelines and more stringent limits
might be added.
8 The facility shall continuously monitor TSS concentration and the dewatering pump shall be
shutoff automatically when the one half of the Daily Maximum limit (15 minutes average) is
Page 4 of 27

Permit NC0004961
A. (3.) EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS (Outfall
002 -dewatering phase) [15A NCAC 02B 0400 et seq., 02B .0500 et seq.]
During the period beginning on the commencement date of the dewatering operations and lasting
until expiration, the Permittee is authorized to discharge from outfall 002 - Ash Pond Discharge
(Dewatering -removing the interstitial water). Such discharges shall be limited and momtored7 by
the Permittee as specified below:
EFFLUENT
CHARACTERISTICS
LIMITS
Monthly Daily
Averdge Maximum
MONITORING REQUIREMENTS
Measurement Sample Type Sample Location
—fmuency
Flow
145 MGD
Weekly
Pump logs or
estimate
Influent or Effluent
Total Suspended Solids'
23 0 m /L
75 0 m /L
Weekly
Grab
Effluent
Oil and Grease
110 m /L
15 0 m /L
Weekly
Grab
Effluent
Total Co ere
10 m L
10 m
Weekly
Grab
Effluent
Total Iron2
10 m L
1 0 m L
Weekly
Grab
Effluent
Total Arsenic
10 5
14 5 /L
Weekly
Grab
Effluent
Total Selenium
13 6 pg1L
25 5 L
Weekly
Grab
Effluent
Total Aluminum
318 m L
318 m /L
Weekly
Grab
Effluent
Total Mercury
47 0 n /Ls
47.0 n 6
Weekly
Grab
Effluent
Nitrate/nitrate as N
013 m
017 m /L
Weekly
Grab
Effluent
Total Phosphorus, m /L
Weekly
Grab
Effluent
Total Nitrogen (NO2 + NO3 + TKN),
m /L
Weekly
Grab
Effluent
H3
Weekly
Grab
Effluent
Chronic Toxicity4
Monthly
Grab
Effluent
Turbidity5, NTU
Weekly
Grab
Effluent
Notes:
1. The facility shall continuously monitor TSS concentration and the dewatering pump shall be
shutoff automatically when the hrmts are exceeded
2. The limits for total copper and total iron only apply when chemical metal cleaning
wastewaters are being discharged.
3 The pH shall not be less than 6.0 standard units nor greater than 9.0 standard units.
4. Whole Effluent Toxicity shall be monitored by chronic toxicity (Cenodaphnia) P/F at 2 7%, see
Part A (5.) for details
5. The discharge from this facility shall not cause turbidity in the receiving stream to exceed 50
NTU. If the instream turbidity exceeds 50 NTU due to natural background conditions, the
discharge cannot cause turbidity to increase in the receiving stream.
NTU - Nephelometric Turbidity Unit
6. The facility shall use EPA method 1631E.
7. No later than 270 days from the effective date of this permit, begin submitting discharge
monitoring reports electronically using NC DWR's eDMR application system See
Special Condition A. (18 ).
The metal cleaning waste, coal pile runoff, ash transport water, domestic wastewater,
and low volume waste shall be discharged into the ash settling pond.
No chemicals, cleaners, or other additives may be present in the vehicle wash water
to be discharged from this outfall. There shall be no discharge of floating solids or
visible foam in other than trace amounts.
The level of water in the pond should not be lowered more than 1 ft/week unless
approved by the DEQ Dam Safety Program.
Page 6 of 27

Permit NC0004961
A. (5.) CHRONIC TOXICITY PASS/FAIL PERMIT LIMIT (Outfall 002) [ 15A NCAC
02B .0200 et seq.]
The effluent discharge shall at no time exhibit observable inhibition of reproduction or significant
mortality to Ceriodaphnia dubia at an effluent concentration of 2.7%.
The permit holder shall perform at a minimum, mon thlu monitoring using test procedures outlined in
the "North Carolina Ceriodaphnia Chronic Effluent Bioassay Procedure," Revised December 2010, or
subsequent versions or "North Carolina, Phase II Chronic Whole Effluent Toxicity Test Procedure"
(Revised- December 20 10) or subsequent versions. Effluent sampling for this testing must be
obtained during representative effluent discharge and shall be performed at the NPDES permitted
final effluent discharge below all treatment processes.
If the test procedure performed as the first test of any single month results in a failure or ChV
below the permit limit, then multiple -concentration testing shall be performed at a minimum,
in each of the two following months as described in "North Carolina Phase II Chronic Whole
Effluent Toxicity Test Procedure" (Revised -December 2010) or subsequent versions.
All toxicity testing results required as part of this permit condition will be entered on the Effluent
Discharge Monitoring Form (MR -1) for the months in which tests were performed, using the
parameter code TGP3B for the pass/fail results and THP3B for the Chronic Value. Additionally,
DWR Form AT -3 (original) is to be sent to the following address:
Attention: North Carolina Division of Water Resources
Water Sciences Section/Aquatic Toxicology Branch
1623 Mail Service Center
Raleigh, North Carolina 27699-1623
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, accurate, include all supporting chemical/ physical measurements and
all concentration/ response data, and be certified by laboratory supervisor and ORC or approved
designate signature. 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 this monitoring requirement 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, minimum control organism reproduction, 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.
A. (6.) BIOCIDE CONDITION
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
Page 8 of 27