NC0004987_Renewal Application_20110118

NCDENR
North Carolina Department of Environment and
Division of Water Quality
Beverly Eaves Perdue Coleen H. Sullins
Governor Director
' January 18, 2011 " '
Mr. Allen Stowe
Water Management,
Duke Energy Corporation,. P.O..Box 1006
Charlotte, North Carolina 28201
Natural Resources
Subject: NPDES Permit Issuance
Permit No. NC0004987
Marshall Steam Station
Catawba County
Dear Mr. Stowe:
Dee Freeman
Secretary
The Division of Water Quality is forwarding herewith the Final NPDES permit for Marshall Steam Station. This permit
renewal is 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 October 15, 2007 (or as
subsequently amended).
A public hearing was held on October 19, 2010 in Mooresville seeking comments on the Draft permit and proposed
continuation of the Clean Water Act Section 316(a) temperature variance. This Final permit incorporates recommendations of
the DWQ Hearing Officer as well as other changes. Listed below are all changes from the previous permit:
• Structural integrity inspection of ash pond dam. Dam safety and design requirements per 15A NCAC 2K are
required.
• CWA Section 3160 Thermal Variance. This condition requires the facility to submit a Balanced and Indigenous
Population (BIP) study plan that conforms to EPA study guidelines, and receives DWQ and EPA concurrence prior
to study implementation. A BIP report must be submitted no later than 180 days prior to permit expiration, should
the permittee request continuation of the CWA Section 316(a) thermal variance.
• Fish Tissue Monitoring Near Ash Pond Discharge. The facility shall conduct fish tissue monitoring near the ash pond
discharge, once during the permit term, and analyze for arsenic, selenium, and mercury. The fish tissue monitoring
shall be in accordance with the Sampling Plan approved by the Division.
• Instream Monitoring. The facility shall conduct semiannual instream monitoring at two BIP monitoring stations
(located upstream and downstream of the ash pond discharge). Samples shall be analyzed for arsenic, selenium,
mercury, chromium, lead, cadmium, copper, zinc, and total dissolved solids (TDS).
• Monitoring for As, Cl, Hg, and Ni was eliminated from the internal Outfall 004 based on the review of the effluent
data and in response to your request
• Groundwater monitoring was added to the permit. Please see Part I, Special Condition 22.
1617 Mail Service Center, Raleigh, North Carolina 27699-1617
Location: 512 N. Salisbury St. Raleigh, North Carolina 27604 One
Phone: [phone] FAX: [phone] Customer Service: 1-877-623-6748 NorthCarolina
Internet: www.ncwaterquality.org 4 1 11,/ /%/
An Equal opportunity lAffirmativeAction Employer a `rdiff

If any Paris, 'measiurement frequencies, or sa`mpling'requirements contained in -this permit 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, 6714 Mail Service Center, Raleigh, North Carolina 27699-6714. Unless such a demand
is made, this permit shall be final and binding.
Please take notice that this permit is not transferable except after notice to the Division of Water Quality. The Division may
require modification or revocation and reissuance of the permit. This permit does not affect the legal requirements to obtain
other permits which may be required by the Division of Water Quality, the Division of Land Resources, the Coastal Area
Management Act, or -any other federal or local governmental permit.
If you have any questions on this permit, please contact Sergei Chernikov at 919-807-6393.
Hardcopy: Central Files, NPDES Files
Mooresville Regional Office, SWPS
NPDES files
Email: US EPA, Region IV
Aquatic Toxicology Unit
Kay Bond, Southern Environmental Law Center [[e-mail]]
David Merryman, Catawba Riverkeeper [[e-mail]]
Hope Taylor, CWFNC [[e-mail]]
1617 Mail Service Center, Raleigh, North Carolina 27699-1617
Location: 512 N. Salisbury St. Raleigh, North Carolina 27604 �TOne 1, 1
Phone: [phone] FAX: [phone] Customer Service: 1-877-623-6748 1 � Olth C ar01111c`l
Internet: www.ncwaterquality.org , P , • � c •
An Equal Opportunity \ Affirmative Adon Employer AHR•tllr�llll,�

f PERMITNo,'NC0004987
STATE OF NORTH CAROLINA
DEPARTMENT OF ENVIRONMENT AND NATURAL RESOURCES
DIVISION OF WATER QUALITY
PERMIT
TO DISCHARGE WASTEWATER UNDER THE
NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM
In compliance with the provisions of North Carolina General Statute 143-21'5.1, 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 Carolinas, LLC
is hereby authorized to discharge wastewater from a facility located at
Marshall Steam Station
At the intersection of NC Highway 150 and NCSR 1841
Terrell
Catawba County
to receiving waters designated as the Catawba River (Lake Norman) in the Catawba
River Basin in accordance with effluent limitations, .monitoring requirements, and
other conditions set forth in Parts I, II, III and IV hereof.
This permit shall become effective March 1, 2011.
This permit and authorization to discharge shall expire at- midnight on April 30, 2015.
Signed.this'day January 18, 2011.
Corn H. Sullins, Director
Division of Water Quality
By Authority of the Environmental Management Commission

PERMIT No.WC0004987 ' r
SUPPLEMENT TO PERMIT COVER SHEET
All previous NPDES Permits issued to this facility, whether for operation or discharge are
hereby revoked, and as of this 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 Carolinas, LLC
is hereby authorized to:
1. Continue to discharge, once -through cooling water and intake screen backwash
through outfall 001; treated wastewater (consisting of metal cleaning wastes,
coal pile runoff, ash transport water, domestic wastewater, low volume wastes,
and FGD wet scrubber wastewater) from the ash settling basin through outfall
002; treated FGD wet scrubber wastewater through internal outfall 004
(upstream of the ash settling basin); yard sump overflows through outfalls 002A
and 002B; and non -contact cooling water from the induced draft fan control
house through outfall 003. All discharges result from activities at Duke Energy's
Marshall Steam Station at the intersection of NC Highway 150 and NCSR 1841
in Terrell, Catawba County;
2. Continue to operate a FGD wet scrubber wastewater treatment system
discharging to the ash settling basin through internal outfall 004; and
3. Discharge from said treatment works at the locations specified on the attached
map into the Catawba River (Lake Norman) which is classified WS -1V and B CA
waters in the Catawba River Basin.

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001 ,
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Facility - p'
Location
Duke Power Corporation
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Marshall Steam Station
Outfall Information
Outfall #:.
001-
Outfall #:
002A and 002B
Receiving Stream: Catawba River.
Receiving Stream:
Catawba
Latitude,
M'35'43'
Latitude:
35°35151'.' '
Longitude:
80°57'52"_
Longitude:
80057'36"
„
Longitude for 002B:
80°57'34"
Outfall #:
002
Outfall #:
003 '
T' Recennnn Stieam: Catawba Rrver
Recernng Stream:
Catawba Rrver
Latitude:
35°36'21'
Latitude:
35°35'52"
Longitude:
_'80°57'35"
Longitude:
80757'47"
Facility - p'
Location
Duke Power Corporation
- Nor t �.� � Nc000�9g7- . ,
Marshall Steam Station
002
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Facility - p'
Location
Duke Power Corporation
- Nor t �.� � Nc000�9g7- . ,
Marshall Steam Station

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•PERMIT No. NC0004987
PART I
1. Effluent Limitations and Monitoring Requirements (Outfall 001)
During the period beginning on the effective date of this permit and lasting until expiration, the
Permittee is authorized to ,discharge from Outfall 001 (once -through cooling,water). Such
discharges shall be limited and monitored by the Permittee as specified below:
LUENT x
:;DISCHARGE LIMITATIONS
;:MONITORING REQiJIRE 1VIENTS
Monthly
"Daily `:
Measurement
Sample
Sample
:Y
CH ARACT ERISTICS
Average,''
"'Maximum`
Frequen
Type
ocatiorr:';'
Pump logs or
Flow (MGD)
Monitor & Report
Daily
similar
Effluent
readings
Temperature
33.3 °C
Daily
Grab
Effluent
(November 1 - Tune 30
Temperature
34.4 oC
Daily
Grab
Effluent
ul 1 - October 31
Free Available Chlorinel
0.2.mg/L
0.5 mg/L
Daily
Grab ; ,
Effluent
NOTES:
1 Once -through cooling water shall not be chlorinated. Should the facility wish to chlorinate once -
through cooling water, a permit modification must be issued prior to commencement of chlorination.
The monitoring requirement and effluent limitations only apply if chlorination is commenced.
There shall be no discharge of floating solids or visible foam in other than trace amounts.

• - PERMIT No. NC0004987
2. Effluent Limitations and Monitoring Requirements (Outfall 002)
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 settling basin discharge). Such
discharges shall be limited and monitored by the Permittee as specified below:
EFFLUENT`,
CHARACTERISTTCS ; '
DISCHARGE LIMITATIONS •
°' MONITORING REQUIREMENTS
Monthly .'
',Average-
Weekly.'-
Average
Daily
,Maximum
Measurement
Frequency-,
Sample,
°',Type
Sample Locations
Flow (MGD)
Monitor & Report
Monthly
Pump logs or
similar readings
Effluent
Oil and Grease
9.0 mg/L
12.0 mg/L
Quarterly
Grab
Effluent
Total Suspended Solids2
20.0 mg/L
65.0 mg/L
Monthly
Grab
Effluent
Total Arsenic
Monitor & Report
Quarterly
Grab
Effluent
Chloride
Monitor & Report
Quarterly
Grab
Effluent
Total Copper
1.0 mg/L
1.0 mg/L
See note 3
Grab
Effluent
Total Iron
1.0 mg/L
1.0 mg/L
See note 3
Grab
Effluent
Total Mercury
Monitor '& Report
Quarterly
Grab
Effluent
Total Nickel
Monitor & Report
Quarterly
Grab
Effluent
Total Selenium
Monitor & Report
Weekly
Grab
Effluent
Total Selenium4
11
29 µg/L
270 µg/L
Weekly
Grab
Effluent
Total Zinc
Monitor & Report
Monthly
Grab
Effluent
Total Nitrogen
02+NO3+TKN
Monitor & Report
Monthly
Grab
Effluent
Total Phosphorus
Monitor & Report
Quarterly
Grab
Effluent
Chronic Toxicity
See Part I, Section A, #14
Quarterly
Grab
Effluent
PH
Between 6.0 and 9.0 Standard Units
Monthly
Grab
Effluent
NOTES:
1 Effluent sampling shall be conducted at the discharge from the ash settling basin prior to mixing with
any other waste stream(s).
2 A total suspended solids monthly average of 40 mg/L is permitted provided the Permittee can
demonstrate that the difference between the monthly average of 20 mg/L and 40 mg/L is the result of
the concentration of total suspended solids in the intake water.
3 Monitoring shall be per occurrence of chemical metal cleaning and samples shall be from a
representative discharge. ,
4 The limits shall become effective on July 1, 2012.
There shall be no discharge of floating solids or visible foam in other than trace amounts.

PERMIT No. NC0004987
3. Effluent Limitations and Monitoring Requirements (Outfall 002A)
During the period beginning on the effective date of this permit and lasting until expiration, the
Permittee is authorized to discharge from Outfall 002A (yard sump # 1 overflows). Such
discharges shall be limited and monitored by the Permittee as specified below:
EFFLUENT. ' `
CHARACTERISTICS,.
DISCHARGE LIMITATIONS
MONITORING REQUIREMENTS
Monthly
-Average'
;; Daily .
Maximum
Measurement
Frequency-
Sample.:
Tye
Sample
Location'
Flow -(MGD)
Episodic
Estimafe
Effluent
pH
Episodic
Grab
Effluent
Total Suspended Solids
Episodic
Grab
Effluent
Total Iron
See note 2
Grab
Effluent
NOTES:
01 Effluent samples shall be collected at a point upstream of the discharge ,to the Catawba River,.
2 Sampling for iron is required when TSS is reported as greater than 100 mg/L.
There shall be no discharge of floating solids or visible foam in other than trace amounts.
All flows shall be reported on monthly DMRs. Should no flow occur during a given month, the words "No
Flow" shall be clearly written on the front of the DMR. Episodic sampling is required per sump overflow
occurrence lasting longer than one hour. All samples shall be of a representative discharge. -

-'PERMIT No. NC0004987 r
4. Effluent Limitations and Monitoring Requirements (Outfall '002B)
During the .period beginning on the effective date of this permit and lasting.until expiration, the
Permittee is authorized to discharge from Outfall 002B (yard sump #2 overflows). Such
discharges shall be limited and monitored by the Permittee as specified below:
EFFLUENT
CHARACTERISTICS
•DISCHARGE LIMITATIONS
'MONITORING REQUIREMENTS
Monthly ,-° '
Average • :
Daily
Maximum
Measurement,, Sample.
Frequency.' _Type '`
Sample
Locations
Flow (MGD)
Episodic Estimate
Effluent
pH
Episodic Grab
Effluent
Total Suspended Solids
Episodic Grab
Effluent
Total Iron
See note 2 Grab
Effluent
NOTES
1 Effluent samples shall be collected at a point upstream of the discharge to the Catawba River.
2 Sampling for iron is required when TSS is reported as greater than 100 mg/ L.
There shall be no discharge of floating solids or visible foam in other than trace amounts.
All flows shall be reported on monthly DMRs. Should no flow occur during a given month, the words "No
Flow" shall be clearly written on the front of the DMR. Episodic sampling is required per sump overflow
occurrence lasting longer than one hour. All samples shall be of a representative discharge.
F�

` PERMIT No. NC0004987
5. Effluent Limitations and Monitoring Requirements (Outfall 003) .
During the period beginning on the effective date of this permit and lasting until expiration, the
Permittee is authorized to discharge from Outfall 003 (non-contact cooling water from the .
induced draft fan control house). Such discharges shall be limited and monitored by the
Permittee as specified below: .
EFFLUENT
DISCHARGE LIMITATIONS
MONITORING -REQUIREMENTS .',
MorithlY
Dail Y s
Measurement
Sam le
P
Sam le
P ' `;
CHARACTERISTICS,
,Average 1
Maximum •
Frequency :°
Type
Location
Flow (MGD)
Temperature'
Total Residual Chlorine2
Free Available Chlorine2
0.2 mg/L
0.5 mg/L
PH
Between 6.0 and 9.0 Standard
Units
NOTES:
1 The temperature of the effluent shall be such as not to cause an increase in the temperature of the
receiving stream of more than 2.80C and in no case cause the ambient water temperature to exceed
29oC.
2 Monitoring requirements apply only if chlorine is added to the cooling water. Neither free available
chlorine nor total residual chlorine may be discharged -from any unit for more than. two hours. in any _
one day and not more than one unit in any plant may discharge free available chlorine or total
residual chlorine at any one time.
There shall be no discharge of floating solids or visible foam in other than trace amounts.
Limitations shall be met at the discharge effluent. Monitoring frequencies are not specified as the
discharge is to the intake canal for outfall 001.

r
PERMIT No. NC0004987
6. Effluent Limitations and Monitoring Requirements (Outfall 004)
During the period beginning on the effective date of this permit and lasting until expiration, the
Permittee is authorized to discharge from Internal Outfall 004 (treated FGD wet scrubber
wastewater to ash settling basin). Such discharges shall be limited and monitored by the
Permittee as specified below: ,
EFFLUENT
'DISCHARGE LIMITATIONS
MONITORING REQUIREMENTS
'Monthly..
Daily :.
Measurement
Sample,'-.`:
= 'Sample "
CH'ARACTER'ISTICS'
_, ;....
Average :
;. w -Maximum
Frequency
Type, '' _'
',_Location!
Pump logs or
Flow (MGD)
Monitor & Report
Monthly
similar
E
readings
Total Selenium
Monitor & Report
Weekly
Grab
E
Total Zinc
Monitor & Report
Monthly
Grab
E
NOTES
1 ' Sample Location: E - Effluent from the constructed wetland prior to discharge to the ash 'settling
basin.
All flows shall be reported on monthly DMRs. Should no flow occur during a given month, the words "No
Flow" shall be clearly written on the front of the DMR. All samples shall be of a representative discharge.
, % .

PERMIT No. NC0004987
7. DEFINITIONS
The term "low volume waste sources" means, taken collectively as if from one source, wastewater from all
sources except those for which specific limitations are otherwise established in this part. Low volume
wastes sources include, but are not limited to: Wastewater from wet scrubber air pollution control
systems, ion exchange water treatment system, water treatment evaporator blowdown, laboratory and
sampling streams, boiler blowdown, floor drains, and recirculating house service water systems. Sanitary
and air conditioning wastes are not considered low, volume wastes.
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.
The term, "chemical metal cleaning waste" means any wastewater resulting from the cleaning of any
metal process equipment with chemical compounds, including, but not limited to, boiler tube cleaning.
Chemical metal cleaning will be conducted according to approved Duke Energy equivalency
demonstration.
The term "FGD wet scrubber wastewater" means wastewater resulting from the use of the flue -gas
desulfurization wet scrubber.
8. TOXICITY RE -OPENER CONDITION ' t
This permit shall be modified, or revoked and reissued to incorporate toxicity limitations and monitoring
requirements in the event toxicity testing or other studies conducted on the effluent or receiving stream
indicate that detrimental effects may be expected in the receiving stream as a result of this discharge.
9.. MONITORING FREQUENCIES
If the Permittee, after monitoring for.at least six months, determines that effluent -limits contained -herein
are consistently being met, it may be requested of the Director that the monitoring requirements be
reduced to a lesser frequency.
10. POLYCHLORINATED BIPHENYL COMPOUNDS
There shall be no discharge of polychlorinated biphenyl compounds such as those commonly used for
transformer fluid.
11. 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 Quality. 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.
12. INTAKE SCREEN BACKWASH
Continued intake screen backwash discharge and overflow from the settling basin are permitted without
limitations or monitoring requirements.
13. BEST MANAGEMENT PRACTICES
It has been determined from information submitted that the plans and procedures in place at Marshall
Steam Station are equivalent to that of a Best Management Practice (BMP).

PERMIT No..NC0004987
14. CHRONIC TOXICITY PASS/FAIL PERMIT LIMIT (QUARTERLY)
The effluent discharge shall at no time exhibit observable inhibition of reproduction or significant
mortality to Ceriodaphnia dubia at an effluent concentration of 12%.
The permit holder shall perform at a minimum,guarterlu monitoring using test procedures outlined in the
"North Carolina Ceriodaphnia Chronic Effluent Bioassay Procedure," Revised February 1998, or
subsequent versions or "North Carolina Phase II Chronic Whole Effluent Toxicity Test Procedure"
(Revised -February 1998) or subsequent versions. The tests will be performed during the months of
'February, May, August, -and November. Effluent sampling for, this testing 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 quarter 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 -February 1998) or subsequent versions.
The chronic value for multiple concentration tests will be determined using the geometric mean of the
highest concentration having no detectable impairment of reproduction or survival and the lowest
concentration that does have a detectable impairment of reproduction or survival. The definition of
"detectable impairment," collection methods, exposure regimes, and further statistical methods are
specified in the "North Carolina Phase II Chronic Whole Effluent Toxicity Test Procedure" (Revised -
February 1998) qr 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 TGP313 for the pass/fail results and THP3B for the Chronic Value. Additionally, DWQ Form AT -3
(original) is to be sent to the following address:
Attention: Environmental Sciences Section
_ North Carolina Division of -
Water Quality
1621 Mail Service Center
Raleigh, North Carolina 27699-1621
Completed Aquatic Toxicity Test Forms shall be filed with the Environmental 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
Environmental Sciences Section at the address cited above.
Should the permittee fail to monitor during a month in which toxicity monitoring is required, monitoring
will be required during the following month. Should any test data from this monitoring requirement or
tests performed by the North Carolina Division of Water Quality indicate potential impacts to the receiving
stream, this permit may be re -opened and modified to include alternate monitoring requirements or
limits. If the Permittee monitors any pollutant more frequently then required by this permit, the results of
such monitoring shall be included in the calculation & reporting of the data submitted on the DMR & all
AT Forms submitted.
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,

h h r
3
✓ PERMIT No. NC0004987
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.
15. ASH SETTLING BASIN
Beginning on the effective date of this permit and lasting until expiration, there shall be no discharge of
plant wastes to the ash pond unless the permittee provides and maintains at all times a minimum free
water volume equivalent to the sum of the maximum 24-hour plant discharges plus all direct rainfall and
all runoff flows to the pond resulting from a 10 -year, , 24-hour rainfall extent, when using a� runoff
coefficient of 1.0.
During the term of the permit, the permittee shall remove settled material from the ponds or otherwise
enlarge the available storage capacities in order to maintain the required minimum volumes at all times.
Annually the permittee shall determine and report to the :permit issuing authority: (1) the- actual. free
water volume of the ash pond, (2) physical measurements of the dimensions of the free water volume in
sufficient detail to allow validation of the calculated volume, and (3) a certification that the required
volume is available with adequate safety factor to include all solids expected to be deposited in the ponds
for the following year. Any changes to plant operations affecting such certification shall be reported to the
Director within five days.
NOTE: In the event that adequate volume has been certified to exist for the term of the permit, periodic
certification is not needed.
16. CHEMICAL METAL CLEANING WASTES
It has been demonstrated that under certain conditions it is possible to reduce the concentration of
metals in boiler cleaning wastes in the range of 92 to 99+ percent by treatment in ash ponds. Because of
dilution problems, and the existence of boundary interface layers at the extremities of the plume, it is
difficult to prove beyond doubt that the quantity of iron and copper discharged will always be less than
one milligram per liter times the flow of metal cleaning when treated in this manner.
The application of physical/ chemical methods of treating wastes has also been demonstrated to be
effective in the treatment of metal cleaning wastes. However, the effectiveness of ash pond treatment
should be considered in relation to the small differences in effluent quality realized between the two
methods.
It has been demonstrated that the presence of ions of copper, iron, nickel, and zinc in the ash pond
waters was not measurably increased during the ash pond equivalency demonstration at the Duke
Energy's Marshall Steam Station. Therefore, when the following conditions are implemented during metal
cleaning procedures, effective treatment for metals can be obtained at this facility:
(1) Large ash basin providing potential reaction volumes.
(2) Well-defined shallow ash delta near•the ash basin influent.
(3) Ash pond pH of no less than 6.5 prior to metal cleaning waste addition.
(4) Four days retention.time in ash pond with effluent virtually stopped.
(5) Boiler volume less than 86,000 gallons.
(6) Chemicals for cleaning to include only one or more of the following:
(a) Copper removal step- sodium bromate, NaBr03; ammonium carbonate, (NH4)2CO3; and
ammonium hydroxide, NH40H.
(b) Iron removal step -hydrochloric acid, HCl; and ammonium bifluoride, (NH4)BF2 and proprietary
inhibitors.
(7) Maximum dilution of wastes before entering ash pond 6 to 1.
(8) After treatment of metal cleaning wastes, if monitoring of basin effluents as required by the permit
reveals discharges outside the limits of the permit, the permittee will re -close the basin discharge,
conduct such in -basin sampling as necessary to determine the cause of nonconformance, will take
appropriate corrective actions, and will file a report with EPA including all pertinent data. .
17. FLOATING MATERIALS
The Permittee shall report all visible discharges of floating materials, such as an oil sheen, to the Director
when submitting DMRs.

f
PERMIT No. NC0004987
18. CHEMICAL DISCHARGES
Discharge of any product registered under the Federal Insecticide, Fungicide, and Rodenticide Act to any
waste stream which may ultimately be released to lakes, rivers, streams or other waters of the United
States is prohibited unless specifically authorized elsewhere in this permit. Discharge of chlorine from
the use of chlorine gas, sodium hypochlorite, or other similar chlorination compounds for disinfection in
plant potable and service water systems and in sewage treatment is authorized. Use of restricted use
pesticides for lake management purposes by applicators licensed by the N.C. Pesticide Board is allowed.
19. PRIORITY POLLUTANT, ANALYSIS
The Permittee shall conduct a priority pollutant analysis (in accordance with 40 CFR Part 136) once per
permit cycle at outfall 002 and submit the results with the application for permit renewal.
20.. - WAIVERS
Nothing contained in this permit shall be construed as a waiver by permittee or any right to a hearing it
may have pursuant to State or Federal laws or regulations.
21. SECTION 316 (II) OF CWA
The permittee shall comply with the Cooling Water Intake Structure Rule per 40 CFR 125.95.
22. GROUNDWATER MONITORING WELL CONSTRUCTION AND SAMPLING
The permittee shall conduct groundwater monitoring to determine the compliance of this NPDES
permitted facility with the current groundwater Standards found under, 15A NCAC .2L .Q200. The
monitoring shall be conducted in accordance with the Sampling Plan approved by the Division.
23. STRUCTURAL INTEGRITY INSPECTIONS OF ASH POND DAM
The facility shall meet the dam design and dam safety requirements per 15A NCAC 2K.
24. CWA SECTION 316(A) THERMAL VARIANCE
The thermal variance granted under Section 316(a) terminates ' on expiration of the NPDES permit.
Should the permittee wish a continuation of its 316(a) thermal variance beyond the term of this permit,
reapplication for such continuation shall be submitted in accordance with 40 CFR Part 125, Subpart H
and Section 122.21(1)(6) not later than 180 days prior to permit expiration. Reapplication shall include a
basis for continuation such as a) plant operating conditions and load factors are unchanged and are
expected to remain so for the term of the reissued permit; b) there are no changes to plant discharges or
other discharges in the plant site area which could interact with the thermal discharges; and c) there are
no changes to the biotic community of the receiving water body which would impact the previous variance
determination.
The next 316 (a) studies shall be performed in accordance with the Division of Water Quality approved
plan. The temperature analysis and the balanced and indigenous study plan shall conform to the
specifications outlined in 40 CFR 125 Subpart H and the EPA's Draft 316a Guidance Manual, dated
1977. The EPA shall 'be provided an opportunity to review the plan prior to the commencement of the
study.
25. FISH TISSUE MONITORING NEAR ASH POND DISCHARGE
The facility shall conduct fish tissue monitoring once during the permit term and submit the results with
the NPDES permit renewal application. The objective of the monitoring is to evaluate potential uptake of
pollutants by fish tissue near the Ash Pond discharge. The parameters analyzed in fish tissue shall be
arsenic, selenium, and mercury. The monitoring shall be conducted in accordance with the Sampling
Plan approved by the Division.
PERMIT No. NC0004987

26. INSTREAM MONITORING
The facility shall conduct semiannual in stream monitoring (one upstream and one downstream of the
ash pond discharge) for arsenic, selenium, mercury, chromium, lead, cadmium, copper, zinc, and total
dissolved solids (TDS). Instream monitoring should be conducted at the stations that have already been
established through the BIP monitoring program. The monitoring results shall be submitted with the
NPDES permit renewal application.

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DENR/DWQ
FACT SHEET FOR NPDES PERMIT DEVELOPMENT
NPDES No. NC0004987
Facility Information _
A licant/Facili Name:
Duke Power Company — Marshall Steam Station
A licant Address_:
Water Management, Duke Energy, P.O. Box 1006, Charlotte, NC 28201
facility Address:
8320 E. NC Highway 150, Terrell, NC 28682
Permitted Flow
Not Limited
Type of Waste:
100% Industrial
Facility/Permit Status:
Renewal
County:
Catawba
ous
Receiving Stream:
Lake Norman
Regional Office: Mooresville
Stream Classification:
WS -IV & B CA
USGS To o Quad: Lake Norman North
M3(d) Listed?: '
No
Permit Writer: ° Sergei Chernikov
Subbasin:
03-08-32
Date: Aril 10, 2010
Drainage Area ° mi2
NA
m
,
Summer 7Q10 (cfs Release 60 cfs)
Winter 7Q10 (cfs): NA
1Q10' cfs :
'IWC f%l: See Below
SUMMARY OF FACILITY AND WASTELOAD ALLOCATION
Duke Energy Company operates Marshall Steam Station in Catawba County. The Station operates five
outfalls. These outfalls are 001, 002, 002a, 002b, and 003. The permitted outfalls are summarized below:
• Outfall 001 —Condenser Cooling Water (CCW) Units 1 — 4:
The CCW system is a once- through, non -contact cooling water system, which condenses steam from
the condensers and other selected heat exchangers. When the station is operating at full power, it has a
design capacity to pump 1463 MGD (1.016 MGPM) of cooling water through the network of tubes that
runs through the condenser and selected heat exchangers. The raw cooling water is returned to the lake.
No biocides or other chemicals are used in the condenser cooling water.
Units 1 and 2 operate two CCW pumps each while units 3 and 4 operate three pumps. The operational
schedule for these pumps is dependent on the intake water temperature and on the unit loads.
Depending on the electrical demand, pumps are operated to maximize station efficiency and to assure
balanced and indigenous populations are maintained in Lake Norman. Each unit is on an independent
system to avoid a system trip that would suddenly reduce the discharge flow at outfall 001. This practice
leads to a higher reliability factor for the units and protection of aquatic life taking refuge in the discharge
canal during cold weather. Flow recorded on the monthly Discharge Monitoring Reports is based on
CCW pump run times.
• Outfall 002 — Ash Basin:
The station ash basin accommodates flows from two yard -drain sumps, an ash removal system, low
volume wastes and non -point source stormwater. Low volume waste sources include, but are not limited
to: wastewater from wet scrubber air pollution control systems, ion exchange water treatment system,
water treatment evaporator blowdown, laboratory and sampling streams, boiler blowdown, floor drains,
and recirculating house service water systems. Total average influent from these sources combined is
approximately 6.7 MGD. At times, due to unit loads, rainfall, evaporation, and seepage of ash basin
ponds, the effluent flow may vary from the influent flow.
• Outfall 004 (internal outfall) — FGD system discharge into Ash Basin:
In association with Clean Smokestacks legislation, Duke Energy will be installing a flu -gas desulfurization
(FGD) wet scrubber. This scrubber will generate a wastewater needing treatment prior to discharge. An.
Marshall Steam Station Fact Sheet
NPDES Renewal
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internal outfall (004) has been established for the effluent from the FGD treatment system. Internal
outfall 004 will discharge to the ash settling basin which is currently permitted as outfall 002. FGD
treatment system includes physical/chemical treatment and wetlands.
The yard -drain sumps are concrete structures having four level controlled pumps each that direct wastewater
from the powerhouse area to the ash basin. These pumps are operated on a rotating basis. Usually two
pumps are set so that one pump is primary and the other is backup. After a selected period the controls are
changed so that different pumps are utilized. The yard -drain sumps collect wastewater from many sources,
such as the filtered water system, turbine and boiler room sumps, miscellaneous equipment cooling water,
foundation drainage, low volume wastes, and tunnel dewatering. The.yard-drain sumps also collect some
stormwater runoff from the coal pile (coal pile runoff), rail access, and powerhouse roofs and pavement.
Groundwater from a foundation drainage system under the track hopper is also intermittently discharged to
the yard -drain sumps. The combined average flow from all sources tied to the yard -drain sumps is
approximately 1.9 MGD, which is pumped to the ash basin for physical and biological treatment.
The turbine room sumps collect approximately 0.2 MGD of wastewater. This wastewater comes from non -
contact cooling water (from Units 1 & 2 boiler feed -pump turbine lube oil coolers) and floor drains. Floor
drains contain boiler blowdown, leakage from seals, equipment cooling water, condensate from the feed -
water system, low volume wastewater, boiler room sump overflow, emergency fire fighting water, general
mechanical maintenance activities, miscellaneous plant wastes and area wash -down water.
The average flow pumped from the boiler room sumps directly to the ash basin is approximately 1.3 MGD.
The sources of input to the boiler room sumps includes the following:
Water Treatment System — the station make-up water treatment system consists of a clarifier,
three gravity filters, two sets of activated carbon filters, and two sets of demineralizers. The
water treatment wastes consist of floc and sedimentation, filter backwash, and demineralizer
regeneration wastes. Make-up water is supplied to the boilers to generate steam to turn the
turbines. On occasion a vendor may be used with a mobile water treatment unit to augment the
facility water treatment capacity. Any vendor will use traditional water treatment methods,
chemicals, and disposal methods.
• Miscellaneous Waste Streams:
• Closed system drainage, cleanings, testing containing corrosion inhibitors (CalgonCS),
biocides (Calgon H-510), cleanings (small heat exchangers), dispersant (polycrylamide),
wetting agent (sodium lauryl sulfate), detergent (tri -sodium phosphate), and leak testing
(disodium fluorescing dye);
• Turbine room sump overflow;
• Boiler seal water (trace oil and grease);
• Miscellaneous system leakages (small leaks from pump packings and seals, valve seals, pipe
connections);
• Moisture separators on air compressor precipitators;
• Floor wash water;
• Emergency fire fighting water;
• Pyrite (ash) removal system overflow;
• Low volume wastewater.
Chemical makeup tanks and drum rinsate - intermittent rinse water containing small amounts of
aluminum sulfate, sodium hydroxide, hydrazine, and ammonium hydroxide.
• Boiler blowdown — Primarily when units 1 & 2 startup and until water chemistry stabilizers the
blowdown from these boilers is allowed to flash in a blowdown tank. During startup a
significant portion of this blowdown steam is vented to the atmosphere. After water chemistry
has stabilized, blowdown venting is minimal and condensate flow is small. Trace amounts of
hydrazine, ammonia, and silica oxide may be present in the condensate. The combined
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NPDGS Renewal
Page 2

' condensate flow from blowdown amounts to an average of approximately 0.002 MGD. This
flow is routed to the boiler room sump and then to the ash basin.
Boiler cleaning — Boilers #1, #2, #3, and #4 at the station are chemically cleaned on an as
needed basis. Tube inspections are performed during outages, which indicate when cleaning
needs scheduling. Boilers #1 and #2 are controlled circulation boilers and boilers #3 and #4
are supercritical boilers. The wastes produced from a boiler cleaning are pumped to the yard
sumps and then to the ash basin.
The ash basin collects stormwater flows from the yard drainage basin, ash removal lines and rainfall runoff
from the basin watershed area. A total of 14.7 acres drain to the yard sumps with an average daily runoff
estimated at 0.03 MGD. The average daily runoff is calculated based on an annual•rainfall of 49 inches with
1.0 and 0.5 runoff coefficients applied appropriately. Trace amounts of oil and grease may be present in the
first flush of stormwater.
Once -through, non -contact cooling water is supplied to eight induced draft (ID) fan motor bearings to
remove excess heat. No chemicals are added to the once -through raw lake water. The rate of flow through
the ID fan heat exchangers that discharges to the yard -drain sumps is approximately 0.08 MGD, which is
pumped to the ash basin.
The track hopper sump collects groundwater from a foundation drain system underneath the track hopper.
The flow is usually intermittent; however, the pump capacity is 100 gpm. On a daily basis it is estimated that
the run time is only 50%, which would correspond to a flow of 0.07 MGD to the yard -drain sumps; then to
the ash basin.
In the event that maintenance activities are needed in the intake or discharge tunnels, a dewatering sump is
provided to remove water from the tunnels. Raw water in the tunnels can be pumped to the yard -drain
sumps that ultimately discharge to the ash basin.
Bore sonic testing of turbine rotors is infrequent, occurring approximately once every 5 years. Demineralized
water is mixed with a corrosion inhibitor, e.g. Immunol 1228, at a ratio of 100 parts water to 1 part inhibitor.
The mixture is applied to the turbine rotors. The excess is drained and mixed with low volume wastewater
and discharged to the ash.basin via the yard -drain sumps.
The station utilizes electrostatic precipitators as its air pollution control devices. Under normal plant
operations, the dry ash captured in these precipitators is collected in temporary storage silos for subsequent
disposal in a permitted on-site landfill or for recycling in off-site ash utilization projects. If the system that
collects the dry fly ash is not operating the fly ash can be sluiced to the ash basin. Bottom ash from the
boilers is usually sluiced with water to a holding cell for recycling activities. Pyrites from the mills are sluiced
with water to an ash basin settling cell. Approximately 2.5 MGD of bottom ash and pyrite sluice is pumped
through large steel pipes (ash lines) directly to the ash basin settling cell. Once -through, non -contact cooling
water from the coal pulverizing mill is discharged to the bottom ash hopper and pumped to the ash basin.
The electrostatic precipitators are normally cleaned by mechanically vibrating the wires and rapping the plates
inside the precipitator. Before major precipitator work is performed, they are cleaned by a wash down. The
wash water is pumped to the ash basin from the yard -drain sump.
A sanitary waste treatment system consists of an aerated basin that provides treatment with a 30 — day
retention time and has a total volume of 587,000 gallons. Effluent from the aerated basin is polished further
through additional residence time in the ash basin. The new system is designed for 6100 gpd (normal) and
13500 gpd (outage).
The powerhouse lift station was installed as a central collection point to receive all the sanitary waste from
the station and ,pump it to the aerated basin. The present lift station serving the vendor facilities and Units 3
and 4 were upgraded.
The sanitary system accommodates wastewater flow from the following courses:
Marshall Steam Station Fact Sheet
NPDES Renewal
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General Plant sanitary wastewater;
Vendor facilities sanitary wastewater; and
Laboratory drains (small amounts of laboratory chemicals used to test wastewater effluents and
high purity boiler water).
Non -point sources of stormwater to the ash basin includes coal pile runoff, a pond area of 82.3 acres and an
up -gradient watershed are of 1097.7 acres. The estimate for stormwater runoff is based on forty-nine inches
of rain per year with a 1.0 and 0.5 runoff coefficient for the pond area and up -gradient watershed,
respectively. The average non -point source stormwater input for the ash basin is estimated at 2.3 MGD.
The coal pile covers an area of approximately 33 acres with an estimated stormwater runoff to the ash basin
of 0.06 MGD.
• Outfall 002a — Sump #1 Overflow:
This outfall discharges very infrequent overflows of yard sump number 1. The overflow generally
consists of the same wastewaters discharged by the ash basin.
• Outfall 002b — Sump #2 Overflow:
This outfall discharges very infrequent overflows of yard sump number 2. The overflow generally
consists of the same wastewaters discharged by the ash basin.
• Outfall 003 — Unit 4 ID Fan Control House Cooling Water:
Once -through; non -contact cooling water is supplied to the Unit 4 induced draft (ID) fan motor control -
house equipment to remove excess heat. No chemicals are added to the once -through raw lake water.
The flow rate through the control equipment that discharges to Lake Norman is approximately 0.2
MGD.
One of the permit requirements is to perform an assessment of balanced and indigenous populations in Lake
Norman. The report states that "the thermal regimes resulting from the operation of the MSS (Marshall
Steam Station have supported the protection and propagation of a balanced and indigenous fish community
in Lake Norman". The Environmental Sciences Section is currently reviewing the report.
BASIS FOR EFFLUENT LIMITS
• Outfall 001 —Condenser Cooling Water (CCW) Units 1 — 4:
Currently, only temperature is limited in this outfall. Summer and winter thermal limits have been
established in support of the 316(A) temperature variance issued by EPA in May of 1975. The
determination noted that the "thermal component of the discharge assures the protection and
propagation of shellfish, fish, and wildlife in and on the receiving body of water." Continued
implementation of the aforementioned thermal variance is supported by the "Assessment of Balanced
and Indigenous Populations in Lake Norman near Marshall Steam Station." Furthermore, an evaluation
of the downstream temperature of Lake Norman suggests that Marshall Steam Station is not appreciably
elevating instream temperature.
A free available chlorine limit is currently part of the effluent limitations for this outfall. 40 CFR 423.12 (b)
(6) establishes maximum free available chlorine concentrations for discharges of once -through cooling water.
These maximum values are 0.5 mg/L and 0.2 mg/L daily maximum and monthly average respectively.
Inclusion of these limits is merely a matter of record keeping as the permit does not authorize chlorination of
the once -through cooling water. These limits will be footnoted such that monitoring is only required if the
facility proposes to implement chlorination of its once -through cooling water.
• Outfall 002 — Ash Basin:
The existing permit limits oil & grease, TSS, pH, selenium, total copper, and total iron at this outfall.
Limits for Cu and Fe are consistent with federal guidelines.
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NPDES Renewal
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• Outfalls 002a and 002b — Yard -Sump Overflows:
On occasion, the yard -sumps at the station experience overflows. These overflows occur rarely, typically
once per year, and can range in time from less than one hour to several hours. Late in 1998, the Division
developed a permitting strategy for these overflows. Analytical monitoring is required for flow, pH, and
TSS for all overflows lasting longer than an hour. When TSS is reported as greater than 100 mg/L,
monitoring for iron is required. All overflows, regardless of time length, are reported to the DWQ
regional office.
• Outfalls 003 — Non -Contact Cooling Water: -
Limitations for this outfall are consistent with non -contact cooling water requirements defined in the
federal guidelines.
TEMPERATURE VARIANCE
The facility has a temperature variance. In order to maintain the variance the facility has to conduct annual
biological and chemical monitoring of the receiving stream to demonstrate that it has a balanced and
indigenous macroinvertebrate and fish community. The latest BIP (balanced and indigenous population)
report was submitted to DWQ in October of 2009. The ESS has reviewed the report and concluded that
Lake Norman near Marshall Steam Station has a balanced and indigenous macroinvertebrate and fish
community.
ESS staff expressed concern regarding low DO concentrations that typically occur during July at two
monitoring stations: Station B and Station C. It must be noted that both stations are part of the man-made
discharge canal, which was excavated for cooling water. In addition, the station withdraws it's cooling water
15 meters beneath the lake surface from the opening along the bottom of the entire skimmer wall. During
hot summer months, water in the lake is subject to stratification that result in a very low DO levels at the
depth from which water is being withdrawn. Evaluation of the lake monitoring data (2000-2008) indicates
that typically in July the level of DO in the lake layer used for withdrawal is very similar to the DO level in
the discharge canal (Station B and Station C). Therefore, low DO concentrations cannot be attributed to the
cooling water discharge.
TOXICITY TESTING:
Current Requirement: Outfall 002 — Chronic P/F @ 12% using Ceriodaphnia
Recommended Requirement: Outfall 002 — Chronic P/F @ 12% using Ceriodaphnia
No changes in the toxicity testing requirements- is recommended. This facility has passed all toxicity tests
during previous permit cycle.
COMPLIANCE SUMMARY:
A review of this facility's effluent data indicates an excellent compliance history with only one permit limit
violation (pH of 5.79 on 03/12/2008) during the review period (1/2006-12/2009).
INSTREAM MONITORING:
None Required
REASONABLE POTENTIAL ANALYSIS (RPA)
The Division conducted EPA -recommended analyses to determine the reasonable potential for toxicants to
be discharged by this facility from outfall. 002. Please see attached.
PROPOSED CHANGES:
• Outfall 002: Monitoring for As, Cl, Hg, and Ni was eliminated from the internal Outfall 004 based on the
review of the effluent data and in response to the permittee's request
Marshall Steam Station Fact Sheet
NPDES Renewal
Page 5

PROPOSED SCHEDULE FOR PERMIT ISSUANCE:
Draft Permit to Public Notice: April 28, 2010 (est.)
Permit Scheduled to Issue: June, 21, 2010 (est.)
STATE CONTACT:
If you have any questions on any of the above information or on the attached permit, please contact Sergei
Chernikov at [phone].
CHANGES TO THE FINAL PERMIT:
The specific changes that have been incorporated into this Final permit are as follows:
• The Special Condition entitled "Structural Integrity Inspections of Ash Pond Dams" was
added to the permit, please see Special Condition #23.
• The Special Condition entitled "CWA Section 316(A) Thermal Variance" was added to the
permit, please see Special Condition #24.
• The Special Condition entitled "Fish Tissue Monitoring near Ash Pond Discharge" was
added to the permit, please see Special Condition #25.
• The Special Condition entitled "Instream Monitoring" was added to the permit, please see
Special Condition #26.
Marshall Steam Station Fact Sheet
NPDES Renewal
Page 6