Marshall Steam Station (7)

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NC®ENR
North Carolina Department of Environment and Natural Resources
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
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 316(a) 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.
e Instreairn lv omtonng The laCuiiy shall conduct semiannual instream monitomig 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 NorthCarohna
Internet www ncwatemuahty nn) 4 % An Equal Opportunity l Affirmative Action Employer Na&rah�

If any parts, measurement frequencies, or -sampling 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 Chemikov at 919-807-6393
Si Cy,
leen H. S lliri
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 [kbond@selcnc org]
David Merryman, Catawba Riverkeeper [david@catawbanverkeeper org]
Hope Taylor, CWFNC [hope@cwfnc org]
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 ncwaterquahty org Naturally.
An Equal Opportunity 1 ABirmative Action Employer - -

a
PERMIT No 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 143-215 1, other
lawful standards and regulations promulgated and adopted by the North Carolina
Environmental Management Commission, and the Federal Water Pollution Control
Act, as amended,
Duke Energy 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.
Coles H. Sullins, Dlrect6r
Division of vv'ater Quality
By Authority of the Environmental Management Commission

PERMIT No NC0004987
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:
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 -IV and B CA
waters in the Catawba River Basin.

a _Outfall Infortnaiion
Receiving Stream Catawba River
Latitude 35°35'43"
Longitude 80°57'52"
Outtall #
002A and 002B
Receiving Stream
Catawba
Latitude
35°35'51"
Longitude
80°57'36"
Longitude for 002B
80°57'34"
I , t I I
r acii><ity � � - ,
Location'"°
Outfall # 002 I Outfall # 003 I I Dike Power Corporation
Receiving Stream - "Catawba RiverY Receiving Stream CRW RiverNCO004q 7 --- _ -4
Latitude T_ 35°36'21" I Latitude 35035'52" !I Ndii
L.orguude b0'S7'35" ' L.onmtude 80`57'47" I I I Marshall Steam Station

PERMIT No. NC0004987
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
Frequency
Sample
Type
Sample
Location'
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

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:
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
6 4
DISCHARGE LIMITATIONS
MONITORING REQUIREMENTS
EFFLUENT
Monthly
Daily
Measurement
Sample
Sample
CHARACTERISTICS
Average
Maximum
Fre uency
Type
Location
Flow (MGD)
Temperature'
Total Residual Chlonne2
Free Available Chlorine 2
0 2 mg/L
0 5 mg/L
Between 6 0 and 9 0 Standard
PH
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
6 4

w
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
CHARACTERISTICS
Average
Maximum
Frequency
Type
Locatioai
Pump logs or
Flow (MGD)
Monitor & Report
Monthly
similar
E
readings
Total Selenium
Monitor & Report
Weekly
Grab
E
Total Zinc
Monitor & Report
Monthly
___r
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
desulfunzation wet scrubber.
8. TOXICITY RE -OPENER CONDITION 0
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 lumps 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 efflucr•t 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)

f,
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 Cenodaphnia dubia at an effluent concentration of 12%
The permit holder shall perform at a minimum, quarterly monitoring using test procedures outlined in the
"North Carolina Cenodaphnia 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 THP313 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,

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 event, 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 hvdroxide. NH40H
(b) Iron removal step-hydrochlonc acid, HCl, and ammonium bifluonde, (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 IMATER ALS
The Permittee shall report all visible discharges of floating materials, such as an oil sheen, to the Director
when submitting DMRs

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 _ v
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 (B) 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 unde'r, 15A NCAC .2L 0200 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
=1

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