NC0004961_Issuance of Permit_20020517

i'
State of North Carolina
Department of Environment
and Natural Resources
Division of Water Quality
Michael F. Easley, Governor
William G. Ross, Jr., Secretary
Gregory J. Thorpe, Ph.D., Acting Director
May 17, 2002
1?W'A
NCDENR
NORTH CAROLINA DEPARTMENT OF
ENVIRONMENT AND NATURAL RESOURCES
Mr Michael Ruhe
Duke Energy Corporation
526 South Church Street
Charlotte, North Carolina 28201-1944
Subject. Issuance of NPDES Permit NC0004961
Riverbend Steam Station
Gaston County
Dear Mr. Ruhe:
Division of Water Quality (Division) personnel have reviewed and approved your application for renewal of
the subject permit. Accordingly, we are forwarding the attached NPDES discharge peanut. Tlus permit 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 May 9, 1994 (or as subsequently
amended).
The following changes have been made to your draft permit:
• Barium, nickel and sulfate monitoring at outfall 002 have been removed from the pernut. During the
comment period, Duke Energy submitted ten data points for each pollutant indicating that the
parameters listed above were not present in the wastestream. Since no reasonable potential to exceed
North Carolina's water quality criteria could be demonstrated, the monitoring for these parameters has
been removed from the permit.
• Limits have been added to your yard sump outfall, 002A. Limits and monitoring are contingent upon
the length and nature of the discharge, please read Part A. (3.) for details.
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 demand is made, flus decision shall be final and binding.
Please note that this permit is not transferable except after notice to the Division. The Division may require
modification or revocation and reissuance of the permit. This pernut does not affect the legal requirements to obtain
other permits which may be required by the Division of Water Quality or perrnits required by the Division of Land
Resources, the Coastal Area Management Act or any other Federal or Local governmental permit that may be
required.
If you have any questions concerning this permit, please contact Natalie Sierra at telephone number (919)
733-5083, extension 551.
cc Central Files
Mooresville Regional Office/Water Quality Section
1VPDES Unit S
Teccluicalilssistance & Certification Unit
Aquatic Toxicology Unit
EPA Region 4
1617 Mall Service Center, Raleigh, North Carolina 27699-1617
An Equal opportunity Affirmative Action Employer
Sincerely,
Nginal Signed
David A. Goodrich
Gregory J. Thorpe, Ph.D.
Telephone [phone] FAX [phone]
VISIT US ON THE INTERNET ® http://h2o.enr state nc.us/NPDES

I�
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 provision 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 Corporation
is hereby authorized to discharge wastewater from a facility located at the
Riverbend Steam Station
Mount Holly
Gaston County
to receiving waters designated as the Catawba River 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 July 1, 2002.
This permit and authorization to discharge shall expire at midnight on February 28, 2005.
Signed this day May 17, 2002.
Original Signed By
David A. Goodrich
Gregory J. Thorpe, Ph.D., Acting Director
Division of Water Quality
By Authority of the Environmental Management Commission

Permit NC0004961
SUPPLEMENT TO PERMIT COVER SHEET
Duke Energy Corporation is hereby authorized to:
1. Continue to discharge:
• Once through cooling water (outfall 00 1) consisting of intake screen
backwash and water from the plant chiller system, turbine lube oil coolers,
condensate coolers, main turbine steam condensers and the intake tunnel
dewatering sump
• Ash basin discharge (outfall 002) consisting of induced draft fan and
preheater bearing cooling water, stormwater from roof drains and paving,
treated groundwater, track hopper sump (groundwater), coal pile runoff,
laboratory drain and chemical makeup tanks and drums rinsate wastes,
ash transport water, general plant/railer sanitary wastewater, metal
cleaning waste, chemical metal cleaning waste, combustion turbine cooling
water discharges, turbine and boiler rooms sumps, vehicle rinse water,
and stormwater from pond areas and upgradient watershed
• Yard sump overflow (002A)
From a facility located at Riverbend Steam Station, Mount Holly in Gaston
County, and
2. Discharge wastewater from said treatment works at the location specified on
the attached map into the Catawba River, which is classified WS -IV and B -CA
waters in the Catawba River Basin.
2

Duke Energy Corporation
Riverbend Steam Station
State Grid/Ouad: F15SW/Mt Island Lake, NC
Receivine Streams:Catawba River
Sub -Basin:
03-08-33
Stream Class:
WS -IV & B -CA
Permitted Flow:
Not limited
Drainaee Basin:
Catawba River Basin
Latitude (001):
350 21' 28" N
Loneitude (001):
80° 58' 12" W
Latitude (002):
350 22' 06" N
Loneitude (002):
800 57' 31" W
Latitude (002A):
35'21'51" N
Loneitude (002A): 80° 58' 11" W
Map not to scale
Facility , -�._--
z�!
Location
North
NPD S Permit No. NC0004961
Gaston Count

1P
Pernut NC0004961
A. (1.) EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS — FINAL
During the period beginning on the effective date of this permit and lasting until expiration, the Permittee is
authorized to discharge once -through cooling water and intake screen backwash from outfall 001. Such
discharges shall be limited and monitored by the Permittee as specified below:
EFFLUENT
CHARACTERISTICS
- LIMITS
MONITORING REQUIREMENTS
Monthly Daily
Average Maximum
Measurement Sample Type Sample Location'
Frequency
Flow
Daily
Pump Logs
Influent or Effluent
Temperature F
95.0 35-C
Daily
Grab
Effluent
Temperature (OF)2
89.6 320C
Daily
Grab
Downstream
Temperature (2F)3
Daily
Grab
Effluent
Notes:
1. Downstream sampling point: downstream at Mountain Island Lake
2. The ambient temperature shall not exceed 89.60F (32.00C) and is defined as the daily average downstream
water temperature. When the Riverbend Station effluent temperature is recorded below 89.60F (32.00C), as
a daily average, then monitoring and reporting of the downstream water temperature is not required. In
cases where the Permittee experiences equipment problems and is unable to obtain daily temperatures from
the existing temperature monitoring system, the temperature monitoring must be reestablished within five
working days.
3. This temperature requirement is in effect when only units with a shared control system are
operating.
1. If the daily average intake temperature is below 36.50F (2.50C), the daily average effluent temperature
shall not exceed 50.00F (100C), and
2. If the daily average intake temperature ranges from 36.50F (2.50C) to 55.00F (12.80C), the daily average
effluent temperature shall not exceed two times the intake temperature (OF) mmus 23.
The Regional Administrator has determined pursuant to Section 316(a) of the Act that the
thermal component of the discharge assures the protection and propagation of a balanced,
indigenous population of shellfish, fish, and wildlife in and on the receiving body of water.
Chlorination of the once through condenser cooling water, discharged through outfall 001, is
not allowed under this permit. Should Duke Power wish to chlorinate its condenser cooling
water, a permit modification must be requested and received prior to commencing
chlorination.
There shall be no discharge of floating solids or visible foam in other than trace amounts.

L
Permit NC0004961
A. (2.) EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS - FINAL
During the period beginning on the effective date of this permit and lasting until expiration, the Permittee is
authorized to discharge from outfall 002. Such discharges shall be limited and monitored by the Permittee as
specified below:
EFFLUENT CHARACTERISTICS
LIMITS
MONITORING REQUIREMENTS
Monthly Daily Measurement Sample Type Sample Location
Avera a Maximum Frequency
Flow
Weekly
Pump logs or
estimate
Influent or Effluent
Total Suspended Solids'
23.0 m I
75 0 mqA
2/month
Grab
Effluent
Oil and Grease
110 moll
15.0 m I
Quarterly
Grab
Effluent
Total Co ere
1.0 m 'I
1.0 m
Quarterly
Grab
Effluent
Total Iron2
1.0 rngil
1.0 m I
Quarterly
Grab
Effluent
Total Arsenic2
Quarterly
Grab
Effluent
Total Selenwm2
Quarterly
Grab
Effluent
Total Phosphorus
Semi-annually
Grab
Effluent
Total Nitrogen NO2 + NO3 + TKN
Semi-annually_Grab
Effluent
Hs
Monthly
Grab
Effluent
Chronic ToxicitY4
Quarterly
Grab
Effluent
Notes:
1. Monthly average of 43 mg/1 is permitted provided that the Permittee can satisfactorily
demonstrate that the difference between 23 mg/1 and 43 mg/1 is a result of the concentration of
total suspended solids in the intake water.
2. Total metals are defined by 40 CFR 136. Any method specified by 40 CFR 136 is considered
acceptable for analysis.
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 (Ceriodaphnia) P/F at 10%. Tests
shall be conducted in January, April, July and October (see Part A.(4.) for details)
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.
0

Permit NC0004961
A. (3.) EFFLUENT LINIITATIONS AND MONITORING REQUIREMENTS — FINAL
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 Overflows. Such discharges shall be limited and
monitored by the Permittee as specified below:
EFFLUENT
CHARACTERISTICS
LIMITS
MONITORING REQUIREMENTS
Monthly Daily
Average Maximum
Measurement Sample Type Sample Location
Frequency
Flow
Episodic
Estimate
Effluent'
H
Eisodic
Grab
Effluent
Total Suspended Solids2
23.0 mg/1
75.0 mg/1
Eisodic
Grab
Effluent
Oil and Grease2
11.0 mg/1
15 0 mV
Eisodic
Grab
Effluent
Fecal Coliform
Eisodic
Grab
Effluent
Total Co era
1.0 MO
1.0 mo
Eisodic
Grab
Effluent
Total Iron3
1.0 mg/1
1.0 mg/1
2
Grab
Effluent
Notes:
1. Effluent sampling shall be conducted at a point upstream of discharge to the receiving stream.
2. The monthly average limits for total suspended solids and oil and grease are applicable only if the
overflow occurs for more than 24 hours.
3. The limits for total copper and total iron only apply during a chemical metals cleaning.
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" SHOULD BE CLEARLY WRITEN ON THE FRONT OF
THE DMR. EPISODIC SAMPLING IS REQUIRED PER OCCURRANCE WHEN SUMP OVERFLOWS
OCCUR FOR LONGER THAN ONE HOUR. ALL SAMPLES SHALL BE OF A REPRESENTATIVE
DISCHARGE.
5

Permit NC0004961
A. (4.) CHRONIC TOXICITY PASS/FAIL PERNHT 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 10%.
The permit holder shall perform at a minimum, puarterlu 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 January, April, July and October. Effluent sampling for this testing shall be performed at the
NPDES permitted final effluent discharge below all treatment processes.
N 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 H 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) 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, DWQ
Form AT -3 (original) is to be sent to the following address:
Attention:North Carolina Division of Water Quality
Environmental Sciences Branch
1621 Mail Service Center
Raleigh, North Carolina 27699-1621
Completed Aquatic Toxicity Test Forms shall be filed with the Environmental Sciences Branch 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 Branch 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.
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.
Gel

Permit NC0004961
A. (5.) 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 nay 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 From 101 and a map locating the discharge point and receiving
stream. Completion of a Biocide Worksheet 101 is not necessary for the introduction of a new biocide
into an outfall currently being tested for toxicity.
A. (6.) SPECIAL CONDITIONS
The following special conditions are applicable to all outfalls regulated by NC0004961:
• There shall be no discharge of polychlorinated biphenyl compounds.
• The Permittee shall check the diked areas for leaks by a visual inspection and shall report any
leakage detected
• If the Permittee, after monitoring for at least six months, determines that he/she is consistently
meeting the effluent limits contained herein, the Permittee may request of the Director that the
monitoring requirement be reduced to a lesser frequency.
• Nothing contained in this permit shall be construed as a waiver by the Permittee or any right to a
hearing it may have pursuant to State or Federal laws or regulations.
• 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 wasters
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 the 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.
• The Permittee shall report all visible discharges of floating materials, such as an oil sheen, to the
Director when submitting DMRs
A. (7.) PERMIT TERMS
The following special conditions are applicable to all outfalls regulated by NC0004961:
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 wastewater 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, cooling tower basin
cleaning wastes, and recirculating service water systems. Sanitary and air conditioning wastes
are not included.
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. Chemical metal cleaning will
be conducted according to Duke Power approved equivalency demonstration.
It has been determined from information submitted that the plans and procedures in place at
Riverbend Steam Station are equivalent to that of a BMP.
A. (8.) SPECIAL CONDITION FOR DISCHARGE OF WASTEWATER
Beginning on the effective date of this permit and lasting until expiration, there shall be no discharge
of plant wastewater to the ash pond unless the Permittee provides and maintains at all times a
minimum free water volume (between the top of the sediment level and the minimum discharge
elevation) 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. The Permittee shall determine and report to the permit issuing
authority the following on an annual basis:
1) the actual free water volume of the ash pond,
%I

Permit NC0004961
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 pond for the following year.
Present information indicates a needed volume of 86.2 acre-feet in addition to solids that will be
deposited to the ash pond; any change 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.
A.(9.) SPECIAL CONDITON - BOILER 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 92-99+ 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 discharge 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 wastewater 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 oat the Duke
Power Company's Riverbend 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 in the ratio of 100 to 1.
2. Well-defined shallow ash delta near the ash basin influent.
3. Ash pond pHs of no less than 6.5 prior to metal cleaning waste addition.
4. Four days retention time in ahs pond with effluent 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 (NaBr02), ammonium carbonate ((NH4)2CO3-H20,
and ammonium hydroxide (NH40H).
b. Iron removal step - hydrochloric acid (HCl), ammonium bifluonde ((NH4)HF2 and
-proprietary inhibitors.
7. Maximum dilution of wastewater before entering ash pond: 6 to 1.
8. If monitoring of basin effluents (as required by the permit) after treatment of metal cleaning
wastes reveals discharges outside the limits of the permit, Permittee will:
1) re -close the basin discharge,
2) conduct such in -basin sampling as necessary to determine the cause of
nonconformance,
3) take appropriate corrective actions, and
4) file a report with EPA including all pertinent data.
N.

Re Riverbend
Subject: Re: Riverbend
Date: Wed, 08 May 2002 15:08 05 -0400
From: [e-mail]
To: Natalie Sierra <Natalie. Sierra@ ncmail.net>
CC: John R Mease <[e-mail]>, Robert R Wylie <[e-mail]>
Look fine!
Take care,
Karrie-Jo Robinson -Shell, P.E.
Shell/R4/USEPA/US@EPA,
Mease
Natalie Sierra
<Natalie.Sierra@n
Robert R Wylie
cmail.net>
05/07/2002 04:54
PM
To: Karrie-Jo
<[e-mail]>, John R
<[e-mail]>
CC:
Subject: Riverbend
All -
Attached are a copy of the pre -final permit for Riverbend and an
addendum to the Fact Sheet. Send all comments to me by Friday.
Thanks,
Natalie
(See attached file: NC0004961_fact sheet3.doc)(See attached file:
NC0004961_final.doc)(See attached file: Natalie.Sierra.vcf)
Name: NC0004961_fact sheet3.doc
NC0004961 fact sheet3 doc Type: Microsoft Word Document (appllcation/msword)
Encoding: base64
Download Status: Not downloaded with message
Name: NC0004961_final.doc
��NC0004961 final.doc Type: Microsoft Word Document (application/msword)
Encoding: base64
Download Status: Not downloaded with message
Name: Natalle.Sierra.vcf
DNatalle.Sierra. vcf Type: VCard (text/x-vcard)
Encoding: base64
Download Status: Not downloaded with message
1 of 1 5/9/02 10 21 AM

Duke
Power.
A Duke Energy Company
March 27, 2002
Ms. Natalie Sierra
North Carolina Department of Environment and Natural Resources
Division of Water Quality
1617 Mail Service Center
Raleigh, North Carolina 27699-1617
Subject: Riverbend Steam Station
NPDES Permit NC0004961
Dear Ms. Sierra.
Duke Power Company
Fossil and Hydro Generation Department
PO Box 1006
Charlotte, NC 28201-1006
APR - 2 2002
DENR -AT-ER QUALITY
POINT SOURCE BRANCH
With reference to your February 13, 2002 memo, Riverbend Steam Station has
conducted additional sampling for barium, nickel and sulfate at the NPDES permitted
outfall 002. It is requested that this data (attached) be reviewed and a determination
be made as to whether monitoring is required by the NPDES permit.
Your evaluation of this information is very much appreciated. If you need additional
information please contact either Robert Wylie at [phone] or David Saleeby at
[phone].
Sincerely,
['�' "'�- --,( 1� /'Z'�
Michael A. Ruhe, Manager
Environmental, Health and Safety
Fossil — Hydro Carolinas
Attachment

Attachment
Riverbend Steam Station
NPDES Permit NC004961
Outfall 002
Analytical Results for
Barium, Nickel and Sulfate
Collection
Date
Banum (ug/1)
Nickel (ug/1)
Sulfate (mg/1)
3/13/02
152.1
6.86
34.02
3/14/02
149.8
6.70
34.04
3/15/02,
152.1
6.81
35.15
3/16/02
155.9
6.84
35.89
3/17/02
154.1
7.04
35.28
3/18/02
154.4
7.15
35.00
3/19/02
151.1
7.16
36.02
3/20/02
140.8
629
36 19
3/21/02
153.8
6.78
3676
3/22/02
155.3
7.17
37.10
Average
151.9
6.88
35.54
Maximum
155.9
7.17
37.10

COMMENTS ON RIVERBEND'S DRAFT' NPDES PERMIT
Subject: COMMENTS ON RIVERBEND'S DRAFT NPDES PERMIT
Date: Mon, 25 Mar 2002 10:02:09 -0500
From: 'Robert R Wylie" <rrwylie@duke-energy corn>
To: Natalie Sierra <[e-mail]>
CC: "David A Saleeby" <[e-mail]>
Natalie,
I plan on forwarding to you this week via mail the analytical results for
barium, nickel and sulfate. A few comments are below on the subject draft
NPDES permit, received from your office:
Under A(2) the sample type for chronic toxicity needs to be changed from
composite to grab. This was previously agreed to due to the large
retention time of the ash basin and a grab sample will be
representative.
Under A(3) (outfall 002A), the description states that the permittee is
authorized to discharge "Once through cooling water". It is recommended
that the phrase "once through cooling water" be deleted and simply state
that the permittee is "authorized to discharge".
In the first sentence under A(8) the word "observable" is used. We
believe "unacceptable" better reflects the toxicity test.
It may be helpful to have the pages numbered.
Depending on conversations with the EPA on the sump overflow issue, this
week I'll likely be sending in comments to the EPA and copying you.
Thanks,
Robert
1 of 1 5/7/02 10 59 AM

,01!1812002 11:13 704-382-9840 DUKE PWR PWR GEN PAGE 02
wDuke Dake Power Company
power. IDSid 4nd Hydro Qncnatirn Boarm at
A Duke EheV Compaq P.O, Box 1006
Charloac, NC 28201-1006
January 19, 20102
Ms. Natalie Sierra
North Carolina Department of Environment and. Natural. Resources
Division of Water Quality
1617 Mail Service Center
Raleigh, North Carolina. 27699-1617
Subject: RXverbend Steam Station
NPDES Permit Number NCO004979
File: RB -006121
Dear Ms. Sierra:
With reference to the draft subject permit that was issued by your Offiiice, Duke Energy
Corporation offers the following comments:
54pplement to Permit Cover Sheet
* Item 1 - In the second bullet please change wash water to rinse water.
* Item 1 -In the third bullet please delete the word "coal" from coal yard sump.
A. 2. Eluent Limitations and Monitoring Reg uirements
It is requested that the measurement frequency for flow stay at weekly instead of
being changed to daily as proposed in this draft permit.
o Due to ibe large size of the ash basin, this treatment system has a relatively long
retention time. It is therefore requested that all composite requirements be
changed to grab samples. A grab sample should be sufficient to represent the
discharge.
Y The analytical results in the NPDES application for Barium, Nickel, Sulfate and
Zinc indicate concentrations sufficiently below the Water Quality Standards. It is
requested that these parameters be removed from Laving to be monitored. The
following table compares the analytical results from the N11DES application to the
North Carolina Water Quality Standards:

,01!1812002 11:13 704-382-9840
DUKE PWR PWR GEN
PAGE 03
Page 2 oft
• Note 2 identifies the in -stream waste concentration as 16%. The IWC should be
10 % as noted in A (4) and also the fact sheet.
• Include a monthly monitoring frequency for pH at outfall 402.
A. f3.1 Eftlnent Limitations &nd Menitorina Requirements
• This outfall is an intermittent discharge Therefore for the parameter iron it is
requested that the sample type be changed from composite to grab. This request
is consistent with the current permit wording.
A. W Chronic Toxig4l Pass/Fail Permit Limit
• The 1st sentence states the effluent disobarge shall at no time exhibit "observable"
inhibition of reproduction or significant mortality to Ceriodaphnia dubaa at an
effluent concentration of 10 %. The word "observable" could potentially be
interpreted to mean that no level is acceptable in which the reproduction level in
the treatment water is less than the control water. Compliance is based on the
mean young produced in the eluent treatment group being less, both statistically
and at a magwitude o£20 percent or greater, than the =an control young
production. Therefore, "observable" needs to be replaced with either
"unacceptable" or "excessive".
A. f5.1 Biocide Condition
• Add to ilie-end of this condition the following: Completion of BMW
Worksheet 101 is not necessary for the introduction ofa uew biocide into an
outfall ctirrently being tested for toxicity.
Additionally it will be helpful if all of tl�e permit pages are numbered. If you need
additional information or have questions please contact Robert Wylie at (704) 3524669.
Since*ely,
Michael A. Ruhe, Manager
cc: David Saleeby—Riverbend $team Station
;4

Plant Allea and Riverbend NPDES Permits
Subject: Plant Allen and Riverbend NPDES Permits
Date: Fri, 3 May 2002 14:38.14 -0400
From: "Robert R Wylie" <rrwylie@duke-energy com>
To: [e-mail]
CC: [e-mail]
Natalie,
Today Ms. Karrie-Jo Shell and I discussed the NPDES permit limits for the
yard sump overflow for Plant Allen and Riverbend. As discussed previously,
the overflows for these systems are very rare. The overflow discharge
pipes are in-place in order to protect the sumps' pump motors from being
exposed to water in case of a malfunction to the pumps and/or electrical
components. Systems are in-place to significantly minimize the likelihood
of an overflow occurrence.
In review of sump systems and their inputs, Karrie-Jo and I agreed that the
permit pages needed some stipulations to better reflect the actual
discharge. The following is a summary of what was discussed:
Riverbend:
The limit of 1.0 mg/l in the Effluent Guidelines (40 CFR 423) for iron
and copper is listed for chemical metals cleaning, only. Therefore,
these limits should not apply unless a chemical metals cleaning is
occuring.
The overflows occur so infrequently that monitoring more than once in a
month is very unlikely. The daily maximum limit for TSS and Oil &
Grease is more applicable. Therefore, the monthly average limits for
TSS and Oil & Grease only apply if the overflow occurs for over 24
hours.
Plant Allen:
The limit of 50 mg/l TSS for the coal yard sump is from 40 CFR 423 also.
However, it applies to coal pile run-off during a rainstorm event. The
layout for the coal yard sump is such that an overflow would most likely
be low volume wastewater instead of coal pile run-off. Chemical metals
cleaning do not go to this sump. Therefore, it was agreed that the
limits for this sump should be O & G - 20 mg/l daily max. and 15 mg/l
monthly average and TSS - 100 mg/l daily max. and 30 mg/l monthly
average. The same rationale of exceeding a 24 hour minimum overflow
time period, as discussed for Riverbend, applies at Plant Allen for
triggering when a monthly average limit is applicable.
Karrie-Jo stated that she will be glad to discuss the above with you.
Thanks,
Robert
704-382-4669
1 of 1 5/7/02 10 59 AM

9 Ou
AFFIDAVIT OF INSERTION OF ADVERTISMENT
PUBLIC NOTICE STATE OF
NORTH CAROLINA DEPART -
The Gaston Gazette
MENT OF ENVIRONMENT
AND NATURAL RESOURCES
Division of Water Quality
Gastonia, NC
Gaston County
Notice of Intent
To Renew NPDESdischarge
Permits in the Catawba River
Basin I)
SUBJECT The Ton of
Water Quality plan to renew
the existent NPDES ermits for
the following facilities
Permit NC0004961 Riverbend
Steam Station County Gaston
I, Jennifer Painter Legal Advertising Manager of the The Gaston Gazette, do cer Subbasin 30833
Permit NC0004979 Facility AI -
that the advertisement of NCDENR len Steam Station County Gas -
Entitle NOTICE OF INTENT:RIVE"END & ALLEN STEAM, ton Substation 30836
PURPOSE The facilities listed
above applied permit for facili-
ties located in Gaston County
discharging treated wastewater
in to the Catawba and South
Fork Catawba Rivers In the Ca-
tawba River Basin Currently
no parameters are water quality
Measuring 9 36 Inches appeared in The Gaston Gazette, a newspaper published in limited The thermal compo-
nent of the discharges is sub -
Gaston County, Gastonia, NC, In issues ject to effluent limitation under
North Carolina Administrative
Code Section 15A NCAC
260211(3)(1) which proposes
thermal effluent limitalons dis-
allowing an exceedence of 2 8
degrees C (5 04 degrees F)
FEBRUARY 21 2002
above
ea ure, and in no caseto
32 degrees C (89 6 de-
grees F) The permit holder has
requested continuance of a
316(a) temperature variance,
which allows for an effl(tent lim-
itation of 35 degrees C (95 de -
Jennifer Painter grees F) On the basis on North
Carolina Administrabye Code
Legal Advertising Managei 2e ti o8(2)(B bj (and othe
law-
ful standards and regulations),
the North Carolina Division of
Sworn to and subscribed before me this day of ,2002 Water Quality proposes to con-
tinue the 316 (a) variance it
conjunction with the renewal of
the permits This dis harge may
affect future alloca ons in thiE
portion of the recei g stream
INFORMATION A opy of the
Notary Public existing NPDES pe its and E
map showing the ocation o
each discharge is available bi
writing or calling
My commission expires May 25, 2003
MS Christie Jackson
NC DENR-DWQ-NPDES Unit
1617 Mad Service Center
Raleigh, North Carohnt
27699-161-7 - _
Telephone number (919
733-5083, ext 551
The existing permits are on ME
at the Division of Water Quality
Archdale Building 512 Nortf
Salisbury Street (Room 925)
Raleigh, North Carolina Thei
may be inspected during nor
mal office hours Copies of the
information on file are availablE
upon request and payment o'
the costs of copying
1C-Februrary 21, 2002

To: Permits and Engineering Unit
Water Quality Section
Attention: Valery Stephens
SOC PRIORITY PROJECT: No
Date: March 21, 2001
NPDES STAFF REPORT AND RECOMMENDATIONS
County: Gaston
NPDES Permit No.: NC0004961
MRO No.: 01-22
PART I - GENERAL INFORMATION
1. Facility and address: Riverbend Steam Station
Duke Power Company
13339 Hagers Ferry Road
Huntersville, N.C. 28078
2. Date of investigation: March 9, 2001
3. Report prepared by: Michael L. Parker, Environ. Engr. II
4. Person contacted and telephone number: John Mease, [phone]
5. Directions to site: From the jct. of Mount Holly-Huntersville Road and Hwy. 16, travel
north on Hwy. 16 = 2 miles (cross over Mountain Island Lake). Turn right at the stop
light onto Steam Plant Road. The Riverbend Steam Plant is located at the end of this
road.
6. Discharge point(s), List for all discharge points: -
outfall 001 outfall 002
Latitude: 350 21'28" 350 21'28"
Longitude: 800 58' 12" 800 58' 12"
Attach a USGS Map Extract and indicate treatment plant site and discharge point on map.
USGS Quad No.: F 15 SW
7. Site size and expansion area consistent with application: Yes.
8. Topography (relationship to flood plain included): The site is located on gently rolling
hills adjacent to Mountain Island Lake (Catawba River). None of the treatment facilities
are located in a flood plain.
9. Location of nearest dwelling: Approx. 1000 feet from the plant site.

Page Two
10. Receiving stream or affected surface waters: Mountain Island Lake (Catawba River)
a. Classification: WS -IV & B
b. River Basin and Subbasin No.: Catawba 030833
C. Describe receiving stream features and pertinent downstream uses: Mountain
Island Lake is used for primary and secondary recreation. The Cities of Mount
Holly and Gastonia use this reservoir as a water supply.
PART II - DESCRIPTION OF DISCHARGE AND TREATMENT WORKS
outfall 001 outfall 002
1. a. Volume of wastewater: 334.6 MGD 6.0 MGD
Sources of wastewater for outfall 001: condenser cooling water, filter backwash
from raw water intake screening device, intake tunnel unwatering sump, and
turbine non-destructive testing.
Sources of wastewater from outfall 002 (ash basin): sanitary wastewater treatment
system, groundwater remediation wastewater, turbine room sumps, ID fan and
pre -heater bearing cooling water, storm water run-off (coal pile area, rail access,
and powerhouse roof, paving, and gravel areas), track hopper sump, filtered water
system, coal pulverizing mill cooling water, closed system drainage (biocidal
additives used in this waste stream), turbine room sump overflow, boiler seal
water, miscellaneous system leak (small leaks from pump packings, seals, valves,
and pipe connections), floor washing, boiler blowdown, and chemical cleaning of
boilers (biocidal additives are used). There is also an outfall listed in the permit
renewal as outfall 002A, which is an overflow pipe built into the Yard Drain
Sump. The Yard Drain Sump carries flow from the sanitary system, groundwater
remediation, and turbine room sumps. There is the potential that wastewater from
the Yard Drain Sump could reach receiving waters should an over flow occur as a
result of pump failure or power not being restored in a timely manner.
b. What is the current permitted capacity: None
C. Actual treatment capacity of current facility (current design capacity): N/A
d. Date(s) and construction activities allowed by previous ATCs issued in the
previous two years: There have been ATCs issued in the previous two years.
Description of existing or substantially constructed WWT facilities: The existing
WWT facilities at outfall 001 consist of screening only. The existing WWT
facilities at outfall 002 consist of three (3) 4000 gallon septic tanks in parallel and
a 1200 gallon holding tank. Additional treatment at outfall 002 includes an
oil/water separator that eventually discharges to an ash basin.
f. Description of proposed WWT facilities: There are no proposed WWT facilities
at this time.

Page Three
g. Possible toxic impacts to surface waters: Biocides are used at various discharge
locations throughout this facility. Any biocidal additives should be approved by
the Division prior to their use.
h. Pretreatment Program (POTWs only): Not Needed.
2. Residual handling and utilization/disposal scheme: Duke Power has obtained DWQ
Permit No. WQ0000452 to reuse ash from the existing ash basin. Residuals from the
existing septic tank are disposed of by septage hauler. Residuals which accumulate in the
storm water collection system (oil trap tanks) are disposed of by vendors who are
equipped to collect and dispose of such materials.
3. Treatment plant classification: Class I (for the GW remediation facilities)
4. SIC Code(s): 4911 Wastewater Code(s): 14, 68, 16, 69
5. MTU Code(s): 50007
PART III - OTHER PERTINENT INFORMATION
1. Is this facility being constructed with Construction Grant Funds or are any public monies
involved (municipals only)? No.
2. Special monitoring or limitations (including toxicity) requests:
a. Duke Power has requested that monitoring for oil and grease be removed at outfall
002. Duke cites data collected from the past two years that have all been below
detection. Defer to the NPDES Unit for comment and approval.
b. Reduction in Selenium and Nitrogen monitoring from monthly to semi-annually.
Defer to the NPDES Unit for comment and approval.
C. Duke request that limits for Fe and Cu at outfall 002 only apply when Duke is
conducting chemical metals cleaning. Duke cites current Steam Electric
Guidelines which restrict Fe and Cu to 1.0 mg/l above background levels. Defer
to the NPDES Unit for comment and approval.
d. Duke requests a continuation of their current thermal limits. Duke supports this
request with study data showing that balanced indigenous aquatic communities
are being maintained at current permit limits.
3. Important SOC/JOC or Compliance Schedule dates: N/A
4. Alternative analysis evaluation: N/A

Page Four
PART IV - EVALUATION AND RECOMMENDATIONS
Duke Power has requested renewal of the subject permit. There have been no changes to
the existing WWT facilities since the permit was last renewed. Duke has requested
modifications to the monitoring as contained in the current permit (see Part III, No. 2 above).
Review and approval of these monitoring changes will be necessary by the NPDES Unit.
Duke has also noted in this renewal the existence of an overflow pipe from a Yard Drain
Sump (see Part II, No. I (a)). Due to the potential for pollutants to reach the receiving waters,
appropriate effluent limitations should be assigned to this outfall consistent with the waste
streams which are tributary.
Pending a final review and approval by the NPDES Unit, it is recommended that the
permit be renewed as requested.
ve, - Z-�� � X'z
Signature of Report Prepay Date
Water Quality Regional Supervisor Date
h \dsr\dsr01\nvebend dsr

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
REGION 4
ATLANTA FEDERAL CENTER
61 FORSYTH STREET
ATLANTA, GEORGIA 30303-8960 n C
MAR 0 8�
Mr David Goodrich
North Carolina Department of Environment and
Natural Resources
Division of Water Quality
NPDES Unit
1617 Mail Service Center
Raleigh, NC 27699-1617
Subject. Draft NPDES Permit no NC0004961
Riverbend Steam Power Plant
Dear Mr Goodrich.
it
ii
MAR 12 2002 _--
In accordance with the EPA/North Carolina Department of Environment and Natural
Resources (DENR) Memorandum of Agreement (MOA), we have completed our review of the
proposed National Pollutant Discharge Elimination System (NPDES) permit for the Riverbend
Steam Power Plant The draft permit and fact sheet were submitted to EPA -Region 4 via letter
dated December 12, 2001 EPA provides the following specific objection regarding this proposed
permit.
In accordance with 40 CFR 122 44(a), the draft pernut must be revised to include the
appropriate effluent linuts for Outfall 002A, which consists of overflow from the Ash Settling
Basin. The Ash Settling Basun treats four waste streams regulated by effluent guidelines cited at
40 CFR 423 12 (metal (,ieantng waste, ash transport water, low volume wastes and coal pie
runoff) In accordance with these regulations, the following limits must be incorporated in to the
permit for Outfall 002A
Internet Address (URL) • http.//www epa gov
Recycled/Recyclable • Printed with Vegetable Oil Based Inks on Recycled Paper (Minimum 25% Postconsumer)
Daily
Monthly
Parameter
Maximum
Average
Oil & Grease, mg/L
200
15.0
Total Suspended Solids, mg/L
1000
300
Total Copper, mg/L
10
1.0
Total Iron, mg/L
10
10
Internet Address (URL) • http.//www epa gov
Recycled/Recyclable • Printed with Vegetable Oil Based Inks on Recycled Paper (Minimum 25% Postconsumer)

In accordance with the MOA and 40 CFR § 123.43 (c)(2)(n), EPA requests that DENR
respond to these concerns and provide copies of any revised proposed permit and fact sheet, for
EPA review prior to final permit issuance If you have an questions or comments, please contact
Kame-Jo Shell of my staff at 404/562-9308
Sincerely,
J Scott Gordon, Chief
Permits, Grants and Technical Assistance Branch
Water Management Division
cc. Mr Michael Ruhe
Duke Energy Corp.

DDuke
Power.
A Duke Energy Company
January 18, 2002
Ms. Natalie Sierra
North Carolina Department of Environment and Natural Resources
Division of Water Quality
1617 Mail Service Center
Raleigh, North Carolina 27699-1617
Subject: Riverbend Steam Station
NPDES Permit Number NC0004979
File: RB -006121
Dear Ms. Sierra:
Duke Power Company
Fossil and Hydro Generation Department
P 0 Box 1006
Charlotte, NC 28201-1006
With reference to the draft subject permit that was issued by your office, Duke Energy
Corporation offers the following comments:
Supplement to Permit Cover Sheet
• Item 1 - In the second bullet please change wash water to rinse water.
• Item 1 - In the third bullet please delete the word "coal" from coal yard sump.
A.(2.) Effluent Limitations and Monitoring Requirements
• It is requested that the measurement frequency for flow stay at weekly instead of
being changed to daily as proposed in this draft permit.
• Due to the large size of the ash basin, this treatment system has a relatively long
retention time. It is therefore requested that all composite requirements be
changed to grab samples. A grab sample should be sufficient to represent the
discharge.
• The analytical results in the NPDES application for Barium, Nickel, Sulfate and
Zinc indicate concentrations sufficiently below the Water Quality Standards. It is
requested that these parameters be removed from having to be monitored. The
following table compares the analytical results from the NPDES application to the
North Carolina Water Quality Standards:
PARAMETER
NPDES APPLICATION
OUTFALL 002
WQS
Barium
269 ppb
J
Nickel
i
�i
= ca
o
C7 ca
Zinc
W
50 ppb
U
cc
O
N
OL
o�
With reference to the draft subject permit that was issued by your office, Duke Energy
Corporation offers the following comments:
Supplement to Permit Cover Sheet
• Item 1 - In the second bullet please change wash water to rinse water.
• Item 1 - In the third bullet please delete the word "coal" from coal yard sump.
A.(2.) Effluent Limitations and Monitoring Requirements
• It is requested that the measurement frequency for flow stay at weekly instead of
being changed to daily as proposed in this draft permit.
• Due to the large size of the ash basin, this treatment system has a relatively long
retention time. It is therefore requested that all composite requirements be
changed to grab samples. A grab sample should be sufficient to represent the
discharge.
• The analytical results in the NPDES application for Barium, Nickel, Sulfate and
Zinc indicate concentrations sufficiently below the Water Quality Standards. It is
requested that these parameters be removed from having to be monitored. The
following table compares the analytical results from the NPDES application to the
North Carolina Water Quality Standards:
PARAMETER
NPDES APPLICATION
OUTFALL 002
WQS
Barium
269 ppb
1000 ppb
Nickel
3.69 ppb
88 ppb
Sulfate
53.8 ppm
250 ppm
Zinc
8 ppb
50 ppb

Page 2 of 2
• Note 2 identifies the in -stream waste concentration as 16%. The IWC should be
10 % as noted in A (4) and also the fact sheet.
• Include a monthly monitoring frequency for pH at outfall 002.
A. (3.) Effluent Limitations and Monitoring Requirements
This outfall is an intermittent discharge. Therefore for the parameter iron it is
requested that the sample type be changed from composite to grab. This request
is consistent with the current permit wording.
A. (4) Chronic Toxicity Pass/Fail Permit Limit
The 1 st sentence states the effluent discharge shall at no time exhibit "observable"
inhibition of reproduction or significant mortality to Ceriodaphnia dubia at an
effluent concentration of 10 %. The word "observable" could potentially be
interpreted to mean that no level is acceptable in which the reproduction level in
the treatment water is less than the control water. Compliance is based on the
mean young produced in the effluent treatment group being less, both statistically
and at a magnitude of 20 percent or greater, than the mean control young
production. Therefore, "observable" needs to be replaced with either
"unacceptable" or "excessive".
A. (5.) Biocide Condition
• Add to the end of this condition the following: Completion of a Biocide
Worksheet 101 is not necessary for the introduction of a new biocide into an
outfall currently being tested for toxicity.
Additionally it will be helpful if all of the permit pages are numbered. If you need
additional information or have questions please contact Robert Wylie at [phone].
Sincerely,
Michael A. Ruhe, Manager
cc: David Saleeby — Riverbend Steam Station

DENR/DWQ
FACT SHEET FOR NPDES PERMIT DEVELOPMENT
NPDES No NC0004961
Facility Information
Applicant/Facility Name
Duke Energy Corporation — Riverbend Steam Station
Applicant Address
13339 Hagers Ferry Road, Huntersville, North Carolina 28078
Facility Address
P O Box 367, Mount Holly, North Carolina 28120
Permitted Flow
No limit
Type of Waste
100% industrial
Prim SIC Code 4911 — Electric Services
Facility/Permit Status
Class I/Active, Renewal
County:
Gaston County
Miscellaneous
Receiving Stream
Catawba River
(Mt Island Lake)
Regional Office:
Mooresville
Stream Classification
WS -IV and B
State Grid / USGS Quad
F15Sw
303(d) Listed?
No
Permit Writer:
Natalie Sierra
Subbasin
03-08-33
Date:
5November01
Drainage Area (mit)
1800
sq
Z zy
001 Lat 351 21' 28" N Long 80° 58' 12" W
002 Lat 351 22' 06" N Long 80° 57' 31" W
002B Lat 35121'51" N Long 80'58' 11"W
Summer 7Q10 (cfs)
80
Winter 7Q10 (cfs).
30Q2 (cfs)'
Avera e Flow (cfs)
2700
IWC (%)'
10%
BACKGROUND
Duke Energy's Riverbend Steam Station is a coal fired steam electric plant in Gaston
County The facility has three permitted outfalls in the current NPDES discharge permit, issued
in July 1996 The sources of wastewater for these outfalls include non -contact cooling water, ash
basin discharge, sanitary waste, stormwater from process areas, and sump overflows The
facility has requested to discharge vehicle wash water from the ash basin outfall, 002
In compliance inspection reports, the Mooresville Regional Office describes the facility
as well maintained with few compliance problems.
In addition to NPDES Permit NC0004961, the facility also holds 0388R20 (air permit)
and NCD024717423 (Hazardous wastes)
Permit Renewal Application:
The permittee submitted the following items for permit renewal.
EPA Form 1
• EPA Form 2E
• EPA Form 2C (with a priority pollutant analysis)
• Site Maps
• Water Flow Diagram
• Supplemental information
The following changes were requested
• Deletion of the oil and grease monitoring requirement at outfall 002
Reduction of selenium and total nitrogen monitoring to semi-annually
Make the iron and copper limits applicable only during a chemical metals cleaning
• Reduction of Total Nitrogen monitoring to semi-annually
J�m sh"t
('.t� 1

The perimttee also requested a continuation of the 316(a) variance for temperature based
on the submitted aquatic life data The permittee also requested the ability to discharge vehicle
washdown water (containing no cleaners, chemicals or other additives) through outfall 002.
Instream Monitoring and Verification of Existing Conditions and DMR Data Review:
The following descriptions of the wastes at each outfall are offered:
001 — once -through condenser cooling water and intake screen backwash
002 — ash basin discharge; includes wastewater from the yard drain sump, groundwater
remediation, turbine room sumps, stormwater runoff, cooling water, reverse osmosis unit,
nusc. seal and lab test waters, boiler blowdown, track hopper sump, boiler room sump
and other nusc process wastewaters.
002A- yard drain sump overflow
This facility discharges to the Catawba River just above Lake Wylie in sub -basin 03-08-
33. The receiving stream is not listed as impaired [303 (d) -listed as of 2000], though dischargers
upstream of Lake Wylie are subject to the nutrient management strategy developed for that
watershed.
One of the permit requirements is to perform an assessment of balanced and indigenous
populations in downstream Lake Wylie. This requires Duke Energy to maintain three
macroinvertebrate sampling stations and three fish monitoring stations The report states that
"Macroinvertebrate data show no adverse impact of the heated discharge on the
macroinvertebrate fauna" and that the diverse fish community is not experiencing atypical levels
of stress. Other than the aquatic life data, no other instream data are collected. The Biological
Assessment Unit has reviewed the report and determined that the discharge does not pose a threat
to indigenous populations and that the 316(a) variance may be extended.
Discharge Monitoring Reports (DMRs) for outfalls 001 and 002 were reviewed from
January 1999 -August 2001. Flow and temperature (upstream, effluent and downstream)are
measured at outfall 001, a discharge consisting of condenser cooling water; flow during this time
averaged 349 MGD. A plot of the temperature data appears in the enclosures The downstream
temperature limit of 89.6°F was not exceeded.
Outfall 002, the ash basin discharge, had an average flow of 4.76 MGD during the DMR
period analyzed. The following table summarizes the effluent data results at outfall 002.
Oil and grease, total copper, total iron, total arsenic, and total selenium were analyzed for
potential to exceed water quality criteria. See the Reasonable Potential analysis section, below
In addition to the aforementioned outfalls, there is one sump overflow outfall — 002A
yard sump overflow This discharges to the Catawba River in the event that all pumps in the
sump fail and was approved in May 15, 2000.
Correspondence.
The correspondence files were reviewed from 1997-2001. The Mooresville Regional
Office (MRO) conducted six site visits and submitted corresponding Compliance Evaluation
RICt Sh:et
NPDES NCo00496! rencmial
[),Joe 2
MONITORED PARAMETERS
Flow
TSS
Oil and
Total
Total
Total
Total
Total
Total
(MGD)
(mg/L)
Grease
Copper
Iron
Arsenic
Selenium
Nitrogen
Phosphorus
(mg/L)
(mg/L)
(mg/L)
/L
/L)
(mg/L)
(mg/L) '
Average
4.76
9.72
Not
001
0.16
76.48
2.64
0.17
0.06
detected
Maximum
6.6
24.5
NA
0 009
0.46
148.4
4.9
022
0.147
Minimum
2.6
3
NA
Not
0.06
29.3
Not
012
0.007
detected
I detected
Oil and grease, total copper, total iron, total arsenic, and total selenium were analyzed for
potential to exceed water quality criteria. See the Reasonable Potential analysis section, below
In addition to the aforementioned outfalls, there is one sump overflow outfall — 002A
yard sump overflow This discharges to the Catawba River in the event that all pumps in the
sump fail and was approved in May 15, 2000.
Correspondence.
The correspondence files were reviewed from 1997-2001. The Mooresville Regional
Office (MRO) conducted six site visits and submitted corresponding Compliance Evaluation
RICt Sh:et
NPDES NCo00496! rencmial
[),Joe 2

Inspection Reports. The facility typically received satisfactory ratings on these reports and was
described as well maintained with an effluent that showed no visible adverse impacts to the
receiving stream. No permit violations were noted during these visits, though the facility did
receive a Notice of Deficiency (NOD) after a site visit in January 1997. This NOD related to a
leak in the null tailings pipe discharging to the ash pond, the leak was discharging directly onto
the ground below the pipe Two compliance biomonitoring inspections were also conducted
during the permit period; the facility passed both
The 2001 staff report prepared for this renewal defers to the NPDES Unit for issues raised
regarding the facility's monitoring requirements in the permit renewal. The office recommends
permit renewal.
The Biological Assessment Unit has prepared comments on the Balanced and Indigenous
Populations report that will be forwarded to the Permittee. In a November 20, 2001 e-mail, Trish
McPherson of the Biological Assessment Unit states that these comments should not delay
permit renewal and are merely intended to improve the presentation and analysis of the reports.
PERMITTING STRATEGY
Waste Load Allocation (WLA).
The Division prepared the last WLA in 1996 for each of the outfalls. The instream waste
concentration (IWC) for 002 was determined to be 10%. The previous and current effluent limits
were based on guidelines and water quality standards. The Division has judged previous
parameters and limits to be appropriate for renewal with some exceptions (see Reasonable
Potential Analysis).
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, based on two and a half
years of DMR data (1999 — August 2001). Calculations included: arsenic (As), selenium (Se),
copper (Cu), iron (Fe), total suspended solids (TSS) and oil and grease (O & G).
Results suggest no reasonable potential for the facility to discharge any of the above
toxicants. Guidelines require that the NPDES permit (see Guidelines section below) limit Fe,
Cu and oil and grease. Monitoring frequency can be reduced to quarterly for iron and copper
(limited by the guidelines) as well as arsenic, selenium, and oil and grease. Due to some of the
levels at which TSS was present in the effluent (several data points close to the permit limit),
monitoring for TSS will remain at twice monthly.
In addition, the primary pollutant analysis was reviewed. 001 discharges non -contact
cooling water and thus no primary pollutant analysis was performed on effluent from this outfall.
The following were detected at outfall 002. aluminum, , bromide, barium, boron, iron,
magnesium, molybdenum, manganese, antimony, arsenic, sulfate, copper, nickel, selenium, zinc,
chromium and cadmium. Several routes were pursued in the determination of monitoring
requirements for these parameters. First, the allowable instream concentrations for all those
parameters with criteria (both NC and EPA recommended criteria) were determined These
allowable concentrations were compared against the detected concentrations. The measured
concentration did not exceed the allowable instream concentration in any case. I then called
Roy Byrd of the NC Division of Water Quality Laboratory section in order to determine whether
or not the concentrations detected were comparable to those seen in the environment. Mr Byrd
confirmed that the concentrations detected for aluminum, magnesium, manganese, antimony,
copper, zinc, chromium and cadmium are either below or in the range of ambient values.
Moreover, given the facility's excellent toxicity record, there is little reason for concern about the
impact of these toxicants on the receiving stream With the exception of zinc, these
parameters shall not have monitoring requirements associated with them beyond what it
fact Sllcct
\T'DES Nc'O004961 Rcnc tial

already present in the NPDES permit. Copper (already monitored in the NPDES permit)
and zinc are now required monitoring parameters for all major industries (at outfalls with
toxicity test requirements) in North Carolina as per the Division's Action Level policy.
To determine how the remainder of the parameters would be treated, I spoke with Marcus
Zobrist of EPA Central (10/24/01). He confirmed that if water quality standards are not present,
no limits should be included. However, he did recommend (for those parameters with water
quality criteria associated with them) a short term monitoring program. This would apply to
barium, sulfate, and nickel. The remainder of the parameters were analyzed using a larger data
set in the Reasonable Potential Analysis Quarterly monitoring is recommended for barium,
sulfate, and nickel. If the permittee wishes to submit 10-12 samples for re-evaluation of the
monitoring requirements, this is permitted under Division policy.
SUMMARY OF PROPOSED CHANGES
In keeping with Division policies the following will be incorporated into the permit:
• Inclusion of vehicle wash water (with footnote disallowing addition of
cleaners, chemicals or other additives to the water) in the description of
wastewater to be discharged from outfall 002.
• Reduce monitoring frequency to quarterly for copper and iron. Include note in
cover letter that if permittee is having compliance problems with these limits,
influent measurements of these toxicants should be collected.
• Reduce monitoring frequency to quarterly for oil and grease, arsenic and
selenium.
• Add quarterly zinc monitoring to outfall 002 as per Action Level policy.
• Add quarterly barium, sulfate, and nickel monitoring to outfall 002. Include
note in cover letter that permittee may wish to test the source water to ensure
that it is not the source of these pollutants
New Weekly Average and Daily Maximum limits are derived from the latest NC/EPA policies
considering 1/z FAVs and allowable concentrations based on reasonable potential.
ENCLOSURES: Reasonable Potential Analysis for outfall 002, primary pollutant analysis (ppa) for 002,
aquatic toxicity data, DMR data for 001 and 002, Mooresville Regional Office staff report.
PROPOSED SCHEDULE FOR PERMIT ISSUANCE
Draft Permit to Public Notice:
Permit Scheduled to Issue
December 5, 2001.
January 21, 2002.
NPDES DIVISION CONTACT
If you have questions regarding any of the above information or on the attached permit, please contact
Natalie Sierra at [phone] ext 551.
NAME: DATE:
Frei sh"eI
\PL)ES NUU00 96! Rene%, a!
('aoe 4

REGIONAL OFFICE COMMENTS
NAME: DATE:
SUPERVISOR: )/o,, -DATE:

Facility Name =
Qw (MGD) _
WWTP Classification
NPDES # _
Receiving Stream
IWC (%) _
asonable Potential Summary
Final Results
Riverbend Station -Duke Power
no limit
1
NC0004961
Catawba River
1000
10 20 30 40
Stream Classification WS -IV B
7Q10s (cfs)= 80 80
30Q2 (cfs)
Qavg (cfs) 2700 2700
ArsenicImplementation
Max Pred Cw
241 2 µg/l
IAre all reported values less than?
No
Limrt9
No
I Monitoring
Allowable Cw
500 0 µg/l
IIs the detection limit acceptable?
Yes
Momtor9
Yes
I Frequency
Monthly
Copper
iImplementation
Max Pred Cw
14 9 µg/l
Are all reported values less than9
No
Limit9
No
!Monitoring
Allowable Cw
70 0 µg/l
IIs the detection limit acceptable9
Yes
Momtor9
Yes
Frequency
Monthly
1/2 FAV
7 3 1 µg/l
1/2 FAV
5 81 µg/l
Iron
' Implementation
'
Max Pred Cw
1 0 µg/1
IAre all reported values less than?
No
Limit?
No
!Monitoring
Allowable Cw
10 0 µg/l
IIs the detection limit acceptable9
Yes
Monitor?
Yes
I Frequency
Quarterly
Oil & Grease
(Implementation
I
Max Pred Cw
2 9 mg/L
Are all reported values less than?
#REFI
Limit9
No
'Monitoring
Allowable Cw
3000 mg/L
IIs the detection limit acceptable9
Yes
Momtor9
Yes
Frequency
Quarterly
Selenium
Implementation
Max Pred Cw
90 pg/1
IAre all reported values less than9
No
Limit?
No
I Monitoring
Allowable Cw
500 pg/I
Is the detection limit acceptable9
Yes
Momtor9
Yes
' Frequency
Quarterly
Total Dissolved Solids
Implementation
Max Pred Cw
478 mg/L
IAre all reported values less than9
No
Limit9
No
!Monitoring
Allowable Cw
5000 mg/L
IIs the detection limit acceptable9
Yes
Monitor?
Yes
I Frequency
Quarterly

Facility Name =
Riverbend Station - Duke Power
NPDES # =
NC0004961
Qw (MGD) =
no limit
7QIOs (cfs)=
80
me (%) =
1000
of data points
FINAL RESULTS
Arsenic
163
Max Pred Cw
241 1630976
Allowable Cw
5000
RESULTS
n <
Std Dev
312428
Mean
765
C V
04085
Number
2
of data points
31
Mult Factor =
163
Max Value
148 4 gg/1
Max Pred Cw
2412 µg/1
Allowable Cw
500 0 µg/1
Parameter = Arsenic
Standard = 500 1 Ag/1
Date
n <
Actual Data
BDL=1/2DL
Jan -99
1
446
44 600
Feb -99
2
31
31 000
Mar -99
3
326
32 600
Apr -99
4
658
65 800
May -99
5
293
29 300
Jun -99
6
641
64 100
Jul -99
7
1215
121500
Aug -99
8
110
110 000
Sep -99
9
1148
114 800
Oct -99
10
851
85100
Nov -99
11
787
78 700
Dec -99
12
628
62 800
Jan -00
13
677
67 700
Feb -00
14
445
44 500
Mar -00
15
778
77 800
Apr -00
16
1172
117 200
May -00
17
1043
104 300
Jun -00
18
140
140.000
Jul -00
19
964
96 400
Aug -00
20
1484
148 400
Sep -00
21
662
66 200
Oct -00
22
61 4
61400
Nov -00
23
351
35100
Jan -01
24
91 2
91 200
Feb -01
25
725
72 500
Mar -01
26
503
50 300
Apr -01
27
575
57 500
May -01
28
585
58 500
Jun -01
29
81
81 000
Jul -01
30
748
74 800
Aug -01
31
858
85 800

Facility Name =
Riverbend Station - Duke Power
NPDES # =
NC0004961
Ow (MGD) =
no limit
7O10s (cfs)=
80
IWC (%) =
1000
70 0
FINAL RESULTS
Copper
3
Max Pred Cw
14 9
Allowable Cw
700
RESULTS
Std Dev 22829
Mean 54
C V 0 423 8
Number
of data points 31
Mult Factor =
1651
Actual Data
Max Value
9 0
µg/1
Max Pred Cw
14 9
µg/1
Allowable Cw
70 0
µg/1
Parameter = Copper
Standard = 70 gg/1
Date
n <
Actual Data
BDL=1/2DL
Jan -99
1 <
50
25
Feb -99
2 <
50
25
Mar -99
3
70
70
Apr -99
4 <
50
25
May -99
5
60
60
Jun -99
6
30
3 0
Jul -99
7
30
3 0
Aug -99
8
30
3 0
Sep -99
9
30
3 0
Oct -99
10
30
3 0
Nov -99
11
30
3 0
Dec -99
12
70
70
Jan -00
13
70
70
Feb -00
14
90
90
Mar -00
15
80
80
Apr -00
16
90
90
May -00
17
60
60
Jun -00
18
90
90
Jul -00
19
80
80
Aug -00
20
30
3 0
Sep -00
21
50
50
Oct -00
22
50
50
Nov -00
23
30
3 0
Jan -01
24 <
50
25
Feb -01
25
70
70
Mar -01
26
80
80
Apr -01
27
60
60
May -O 1
28
60
60
Jun -01
29
70
70
Jul -01
30
70
70
Aug -01
31
60
60

Facility Name = Riverbend Station - Duke Power
NPDES # = NC0004961
Qw (MGD) = no limit
7QIOs (cfs)= 80
IWC (%) = 1 1000
FINAL RESULTS
Iron
Max Pred Cw 10
Allowable Cw 100
RESULTS
Std Dev 0 1058
Mean 02
C V 06721
(Number
of data points 31
Factor =
2 1
Value
0 5 gg/1
Pred Cw
10 µg/l
Mable Cw
10 0 gg/l
Parameter = Iron
Standard = 10 mg/l,
Date
n
< Actual Data
BDL=1/2DL
Jan -99
1
015
015
Feb -99
2
011
011
Mar -99
3
013
013
Apr -99
4
007
007
May -99
5
013
013
Jun -99
6
01
010
Jul -99
7
013
013
Aug -99
8
012
012
Sep -99
9
008
008
Oct -99
10
009
009
Nov -99
11
0 11
0 11
Dec -99
12
027
027
Jan -00
13
035
035
Feb -00
14
032
032
Mar -00
15
028
028
Apr -00
16
046
046
May -00
17
027
027
Jun -00
18
037
037
Jul -00
19
011
011
Aug -00
20
O1
010
Sep -00
21
024
024
Oct -00
22
008
008
Nov -00
23
008
008
Jan -01
24
O1
010
Feb -01
25
008
008
Mar -01
26
014
014
Apr -01
27
013
013
May -01
28
006
006
Jun -01
29
007
007
Jul -01
30
007
007
Aug -01
31
008
008

Facility Name =
NPDES # =
Qw (MGD) =
7O10s (cfs)=
IWC (%) =
Riverbend Station - Duke Power
NC0004961
no limit
80
1000
owable Cw
300 0 mg/L
FINAL RESULTS
Oil & Grease
Max Pred Cw
Allowable Cw
29
3000
RESULTS
Std Dev 08896
Mean 10
C V 08755
of data points 0
It Factor =
1 15
x Value
2 5 mg/L
x Pred Cw
2 9 mg/L
owable Cw
300 0 mg/L
Parameter = Oil & Grease
Standard = 300 mg/L
Date
n <
Actual Data
BDL=1/2DL
Jan -99
<
1 0
05
Feb -99
<
1 0
05
Mar -99
<
1 0
0 5
Apr -99
<
1 0
05
May -99
<
1 0
05
Jun -99
<
1 0
0 5
Jul -99
<
1 0
05
Aug -99
<
10
05
Sep -99
<
10
05
Oct -99
<
1 0
05
Nov -99
<
10
05
Dec -99
<
1 0
05
Jan -00
<
1 0
05
Feb -00
<
1 0
05
Mar -00
<
10
05
Apr -00
<
1 0
05
May -00
<
1 0
05
Jun -00
<
1 0
05
Jul -00
<
1 0
05
Aug -00
<
1 0
05
Sep -00
<
1 0
05
Oct -00
<
1 0
05
Nov -00
<
1 0
05
Jan -01
<
50
25
Feb -01
<
50
25
Mar -01
<
50
25
Apr -O 1
<
50
25
May -01
<
50
25
Jun -01
<
50
25
Jul -01
<
50
25
Aug -01
<
50
25

Facility Name =
Riverbend Station - Duke Power
NPDES # =
NC0004961
Qw (MGD) =
no limit
7Q1Os (cfs)=
80
IWC (%) =
1000
Feb -99
FINAL RESULTS
Selenium
2
Max Pred Cw
90
Allowable Cw
500
RESULTS
Std Dev 09767
Mean 18
C V 05284
of data points 31
Factor =
1 85
Value
4 9 µg/l
Pred Cw
9 0 µg/1
viable Cw
50 0 gg/l
Parameter= Selenium
Standard = 50 1 µg/l
Date
n
<
Actual Data
BDL=1/2DL
Jan -99
1
<
2
10
Feb -99
2
<
2
10
Mar -99
3
<
2
10
Apr -99
4
22
22
May -99
5
<
2
10
Jun -99
6
<
2
10
Jul -99
7
<
2
10
Aug -99
8
<
2
10
Sep -99
9
25
25
Oct -99
10
<
2
10
Nov -99
11
<
2
10
Dec -99
12
<
2
10
Jan -00
13
<
2
1 0
Feb -00
14
<
2
10
Mar -00
15
22
22
Apr -00
16
29
29
May -00
17
24
24
Jun -00
18
34
34
Jul -00
19
29
29
Aug -00
20
49
49
Sep -00
21
23
23
Oct -00
22
23
23
Nov -00
23
<
2
10
Jan -01
24
31
31
Feb -01
25
26
26
Mar -01
26
22
22
Apr -01
27
21
21
May -01
28
<
2
10
Jun -01
29
22
22
Jul -01
30
<
2
10
Aug -01
31
2 1
2 1

Facility Name =
NPDES # =
Qw (MGD) =
7Q10s (cfs)=
IWC (%) =
Riverbend Station - Duke Power
NC0004961
no limit
80
1000
C V
0 5832
FINAL RESULTS
TDS
Max Pred Cw
Allowable Cw
478
5000
RESULTS
n <
Std Dev
56685
Mean
97
C V
0 5832
Number
2
of data points
31
Mult Factor =
195
Max Value
24 5 mg/L
Max Pred Cw
47 8 mg/L
Allowable Cw
500 0 mg/L
Parameter = TDS
Standard = 5000
Date
n <
Actual Data
BDL=1/2DL
Jan -99
1
45
45
Feb -99
2
5
50
Mar -99
3
6
60
Apr -99
4
65
65
May -99
5
5
50
Jun -99
6
9
90
Jul -99
7
3
3 0
Aug -99
8
75
75
Sep -99
9
45
45
Oct -99
10
6
60
Nov -99
11
13 3
13 3
Dec -99
12
16
160
Jan -00
13
215
215
Feb -00
14
9
90
Mar -00
15
13
13 0
Apr -00
16
22
220
May -00
17
16
160
Jun -00
18
245
245
Jul -00
19
65
65
Aug -00
20
75
75
Sep -00
21
16
160
Oct -00
22
6
60
Nov -00
23
7
70
Jan -01
24
8
80
Feb -01
25
8
80
Mar -01
26
14
140
Apr -01
27
12
120
May -01
28
5
50
Jun -01
29
5
50
Jul -01
30
65
65
mg/L

Primary pollutant analysis results for Duke Energy's Riverbend Steam Plant
NC0004961
Outfall 002
Parameter of concern
Bromide Aluminum Barium Boron Iron Magnesium Molybdenum Manganese Antimony Arsenic
(mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (ug/L) (ug/L}
Actual concentration 29 0.168 0 269 0 367 0.58 247 0 079 0.016 10.6 1484
Allowable concentration not a POC 75.00 10 not a POC 10 not a POC not a POC 2 not a POC 500
Pnrnmptpr of r_nnrarn
Sulfate
MEMO(mg/L)
Copper
Nickel Selenium
Zinc
Chromium Cadmium
(mg/1)
(ug/L) (ug/L)
(mg/L)
(ug/L) (ug/L)
001
3,69 4.9
0.008
3.29 0.98
Actual concentration 53.8
Allowable concentration 2500
07
250 50
0.5
500 20
red font indicate,, that all Conc Based upon EPA Rec Criteria
fields in bold (no highlighting) indicate that concentration detected is around ambient or tap water values (conversation with Roy Byrd, 10/24/01)
fields with highlighting indicate those parameter~ that will require periodic monitoring to ensure that the discharge has no impact on the water quality of the receiving ,tream

Whole Effluent Toxicity Testing Self -Monitoring Summary October 17, 2001
FACILITY REQUIREMENT YEAR JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
Duke Power-CldTside Penn chr Inn 5 6% (Grab)
1997 —
—
Pass
--
—
Pass
—
—
Pass
—
—
Pass
NC0005098/002 Begin 3/1/1999 Frequency Q P/F + Mar Jun Sep Dec
+ NonComp Single
1998 —
—
Pass
—
—
Pass
—
—
Pass
--
—
Pass
County Rutherford Region ARO Subbasin BRD02
1999 —
—
Pass
—
—
Pass
—
—
Pass
—
—
Pass
PF 88 Special
2000 —
—
Bl
—
—
Pass
—
—
Pass
—
—
Pass
7Q10 287 IWC(%)453 Order
2001 —
—
Pass
—
—
Pass
—
—
Duke Power -Dan River Perm chr hin 0 88% (Grab)
1997 —
--
>100
—
--
Pass
—
—
Pass
—
—
Pass
NC0003468/002 Begin 6/1/1997 Frequency Q + Mar Jun Sep Dec
+ NonComp Single
1998 —
—
Pass
—
—
Pass
—
—
Pass
—
—
Pass
County Rockingham Region WSRO Sublimin ROA03
1999 —
—
Pass
—
—
Pass
—
—
Pass
—
—
Pass
PF 1 8 Special
2000 —
—
Bt
—
—
Pass
—
—
Pass
Pass
7Q10 3140 IWC(%)0879 Order
2001 —
—
Pass
—
—
Pass
—
—
Duke Power -Lincoln Turbine P -2 -Perm chr lim 23% (Grab)
1997 —
—
>92
—
—
>92
--
—
>92
--
—
>92
NCO080781/001 Begin 9/1/1996 Frequency Mar Jun Sep Dec
NonComp ChV Avg
1998 —
—
6505
--
—
325
—
--
6505
—
—
>92
County Lincoln Region MRO Subbasm CTB33
1999 —
—
>92
--
—
>92
—
—
>92
--
—
6505
PF 04 Special
2000 —
—
>92
--
—
>92
--
—
6505
—
--
6505
7QI0 21 IWC(%)23 Order
2001 --
--
>92
--
—
>92
—
-
Duke Power -Marshall 002 Perm chr lim 12% (Grab)
1997 —
Pass
—
--
Pass
—
—
Pass
—
—
Pass
—
NC0004987/002 Begin 8/1/2001 Frequency Q Feb May Aug Nov
+ NonComp Single
1998 —
Pass
—
—
Pass
—
—
Pass
>48
—
Pass
—
County Catawba Region MRO Subbmin CTB32
1999 —
Pass
—
—
Pass
—
—
Pass
—
—
Pass
—
PF 5 3 Special
2000 —
Pass
—
—
Pass
-
--
Pass
—
--
Pass
--
7Q10 600 IWC(%) 12 0 Order
2001 —
Pass
—
—
Pass
—
—
Pass
Duke Power -McGuire 001 Perm 24hr p/f ac lim 90% (Certo)
1997 —
Pass
—
—
Pass
—
—
Pass
—
—
Pass
—
NC0024392/001 Begin 10/1/2000 Frequency Q + Feb May Aug Nov
+ NonComp Single
1998 —
Pass
—
—
Pass
—
—
Pass
--
—
Pass
--
County Mecklenburg Region MRO Sublimin CTB32
1999 —
Pass
--
—
Pass
--
--
Pass
--
--
Pass
--
PF NA Special
2000 —
Pass
—
—
Pass
—
—
Pass
—
—
Pass
—
7Q10 80 IWC(%)90 Order
2001 —
Pass
--
--
Pass
--
—
Pass
Duke Power -McGuire 002 Penn 48hr LC50 ac lim 64% (Grab)
1997 —
>100
—
--
>100
--
--
>100
--
--
>100
-
NC0024392/002 Begin 10/1/2000 Frequency Q + Feb May Aug Nov
+ NonComp Single
1998 —
>100
—
—
>100
—
—
>100
—
—
>100
—
County Mecklenburg Region MRO Subbasin CTB33
1999 —
>100
—
—
>100
—
-
>100
--
—
>100
—
PF 0 3315 Special
2000 —
>100
—
—
>100
—
—
>100
—
—
>100
--
7QI0 900 IWC(%) 0 64 Order
2001 —
>100
—
—
>100
—
—
>100
Duke Power -McGuire 005 Perm chr lira 14% (Grab)
1997 Pass
--
—
Pass
—
—
Pass
—
—
Pass
--
--
NC0024392/005 Begin 10/1/2000 Frequency Q Jan Apr Jul Oct
+ NonComp Single
1998 Pass
—
—
Pass
—
--
Pass
—
—
Pass
--
—
County Mecklenburg Region MRO Subbasin CTB33
1999 Pass
—
—
Pass
—
—
Pass
—
—
Pass
—
—
PF 0 754 Special
2000 Pass
—
—
Bt
—
—
Late
Pass
—
Pass
—
—
7Q10 800 IWC(%)14 Order
2001 Pass
—
—
Pass
—
—
Late
Pass
Duke Power -River Bend 002 / Perm chr Inn 10% (Grab)
Y 1997 Pass
—
—
Pass
—
—
Pass
—
—
Pass
--
--
NC0004961/002 Begin 9/1/1996 Frequency Q P/F + Jan Apr Jul Oct
NonComp Single
1998 Pass
—
—
Pass
—
—
Pass
—
—
Pass
—
—
County Gaston Region MRO Subbasm CTB33
1999 Pass
—
—
Pass
—
—
Pass
—
—
Pass
—
—
PF NA Special
2000 Pass
—
—
Bt
—
—
Late
Pass
—
Pass
--
—
7Q10 800 IWC(%)1036 Order
2001 Pass
—
—
Pass
—
—
Late
Pass
Dunn/Blacknver W\VTP Perm chr Irm 1%
1997 --
—
Pass
—
—
Pass
—
--
Pass
—
—
Pass
NCO043176/001 Begin 9/1/1996 Frequency Q P/F + Mar Jun Sep Dec
NonComp Single
1998 —
—
Fa ,Pass
—
—
Pass
—
—
Pass
—
--
Pass
County Harnett Region FRO Subbasm CPF13
1999 --
—
Pass
--
—
Pass
—
--
Pass
--
—
Pass
PF 3 75 Special
2000 —
--
Pass
—
—
Pass
—
--
Pass
--
--
Pass
7Q10 5866 IWC(%) 1 0 Order
2001 —
—
Pass
--
—
Pass
—
--
Dupont De Nemours Penn chr lim 3 3%
1997 —
Pass
—
—
Pass
—
—
Pass
--
—
Pass
—
NC0003573/001 Began 9/1/1996 Frequency Q P/F + Feb May Aug Nov
NonComp Single
1998 —
Pass
--
—
Pass
--
--
Pass
—
—
Pass
—
County Bladen Region FRO Subbasm CPF16
1999 —
Pass
--
—
Late
Pass
--
Pass
—
—
Pass
—
PF 17 Special
2000 —
Late
Pass
—
Pass
—
—
Pass
—
—
Pass
—
7Q10 7910 IWC(%)33 Order
2001 —
Pass
Pass,Pass
--
Pass
—
--
Pass
Durham Co -Triangle WWTP Penn chr lira 90%
Y 1997 —
Pass
--
—
Fal
Pass
—
Fal
Pass
—
Pass
—
NC0026051/001 Begin 4/1/1996 Frequency Q P/F + Feb May Aug Nov
NonComp Single
1998 —
Pass
-
—
Passsig
--
—
Pass
—
—
Pass
—
County Durham Region RRO Subbmin CPF05
1999 --
Pass
—
—
Pass
—
—
Pass
—
—
NR/Pass
—
PF 60 Special
2000 --
NR/Pass
--
—
Bt
—
Pass
Pass
—
—
Pass
—
7Q10 00 IWC(%)100 Order
2001 --
Pass
--
—
NR/Pass
—
—
Pass
Y Pre 1997 Data Available
LEGEND
PERM = Permit Requirement LET = Administrative Letter - Target Frequency= Monitoring frequency Q- Quarterly, M- Monthly, BM- Bimonthly, SA- Semiannually, A- Annually, OWD- Only when discharging, D- Discontinued monitoring requirement
Begin= First month required 7Q10 = Receiving stream low flow criterion (cls) += quarterly monitoring increases to monthly upon failure cr NR Months that testing must occur - ex Jan, Apr, Jul, Oct NonComp = Current Compliance Requirement
PF = Permitted flow (MGD) IWC%= Instream waste concentration P/F = Pass/Fail test AC = Acute CHR= Chronic
Data Notation f- Fathead Minnow,* - Cenodaphnia sp , my - Mysid shrimp, ChV -Chronic value, P -Mortality of stated percentage at highest concentration, at - Performed by DW Q Aquatic Tax Unit, bt -Bad test
Reporting Notation --- = Data not required, NR - Not reported Facility Activity Status I - Inactive, N - Newly Issued(To construct), H - Active but not discharging, 1 -More data available for month in question, • = ORC signature needed
17

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State of North Carolina
Department of Environment
and Natural Resources
Division of Water Quality
Mich el F. Easley, Governor
Willia G. Ross, Jr, Secretary
Grego J. Thorpe, Ph D , Acting
MEM
TO: Chary s Weaver
NPDES\Unit
FROM: Natalie Sieh
Engineer, D
SUBJECT: 7Q10 Flow for
Director
September 21, 2001
— NPDES Unit
ES Permit
I have reviewed Mr. McCall's letter and t e accom
7Q10 flow for the receiving stream, an unn ed tri
methodologies. The first follows that of Mr. u is
2001 correspondence to Mr McCall. Using th ec
and the drainage area for the subject dischar , I t
calculated a 30Q2 flow of 0.104 ft3/s and inter i
flow assessment on which the current p it limits
A��
RCDENR
— Pines Mobile Home Park
,aXing submittal from USGS. In order to evaluate
Y{itary to Crowders Creek, I employed two
Weaver of USGS and is described in the April 19,
;ntly (199 1) recalculated 7Q10 for Crowders Creek
obtained a 7Q10 flow of 0.050 ft3/s. I also
10 of 0.078 ft3/s. Mr. Weaver states that the zero
sr based was determined based on equations that
were used in the 1970s and 80s but at no longer used i assessments of low -flow characteristics.
As a check to this first method, I also calculated the 7Q10ow based upon the 1993 USGS report, "Low -
Flow Characteristics of Streams/in North Carolina." The sub ect facility is located in hydrologic area 9
(HA9) — the Charlotte Belt a ociMilton Belt. In this region, its ould be noted, drainage areas below 1
square mile are generally ated with zero flow. The region equations for this hydrologic area are
as follows:
7Q10 = 0.196DAo 13
30Q2 = 0.316DAo s3
where DA is dratage area. For this facility's outfall, the drainage ar\is28 mit This results in 7Q10
flow of 0.0998*/s and 30Q2 flow of 0.083 ft3/s.
The flow i0he unnamed tributary to Crowders Creek is therefore very low, but hould not be considered
zero. The limits shall be recalculated using the flow data provided by US in its April 19, 2001
corresnaridence to Mr. McCall.
P O Box 29535, Raleigh, North Carolina 27626-0535 Telephone [phone] FAX [phone]
An Equal Opportunity Affirmative ,action Employer 50% recycled / 10% post -consumer paper

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• The request for flow expansions (as described in the Phase II A -C plans contained in
your application) cannot be granted at this time. Modeling work of the mainstem of
the Cape Fear River is currently being pursued to assess the current water quality
conditions as well as the impact of new discharges on dissolved oxygen and other water
quality parameters Until modeling is complete, expansion and new discharge requests
cannot be accepted
Submit any comments or questions concerninghis draft permit no later than thirty (30) days
following receipt�of this letter Comments should be sent to
/
Ms Natalie Sierra
1\ CDENR -/DWQ -NPDES Unit
1617 �Aail Service Center
Raleigh, Nprth Carolina 27699-1617
If you have any questio s or comments concerning this draft permit, please contact me at
919-733-5083 extension 551 or a e-rdail at Natalie [e-mail].
Sincerely,
Nabhe V Sierra
NPDVS Unit
cc Fayetteville Region I Office/Water Quality
NPDES Unit
Aquatic Toxicology Unit
Mr Roosevelt Childress, EPA Region IV
Mr Manhar Pdel, Monsanto Company
Ms. Hope Walters, Monsanto Company

DFS3650I SESSION READY FOR INPUT
toy 91C1
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In February 2000, the Technical Assistance and Certification Unit assessed the facility as a Grade
3 Bi logical Water Pollution Control System
PERM'QTING STRATEGY
Waste Loa Allocation (WLA)
The vision prepared the last WLA in 1993 The previous effluent limits were based on
guidelines and ater quality standards At the time, Monsanto was discharging from three outfalls
Outfall 003 will be immated in this. renewal at the request of the per i(ttee For the 1995 renewal of the
permit, the Division veloped site-specific effluent limitationWi"',
sed on best professional judgement
(BPJ) These are describ din the section entitled " Site -Specific below.
Reasonable Potential Analy is (RPA).
The Division conduct EPA -recommended anal y es to determine the reasonable potential for
toxicants to be discharged by th facility, based on/and
three years of OE—P � data (January 1997 —
November 1999) The Permittee hes\ requested a redin monitoring frequency for the OCPSF scan
and the elimination of the effluent li>r3�ts on the met cyanide. It is for this reason that a reasonable
potential analysis was performed. It slid Id be
the remaining parameters appear as non teci
their monitoring frequencies reduced to arm a,
The results of the r.
violate the effluent limits for chromium,/co
parameters will therefore remain in plac, and
'd that only the metals and cyanide were ever detected,
the OCPSF scan reports These parameters will have
analysis suggest reasonable potential for the facility to
;r, cyanide, lead, nickel and zinc The limits for these
monitoring frequency will remain at quarterly .
Site Specific BPJ /
For the 1995 NPDES permit renewal, 14the Permits and
Engineering Unit developed site-sp`eecific BPJ limits r :844 h49se parameters not covered by the pesticide
and OCPSF guidelines that wer��Ac
onsidered pollutants of concern A copy of a memo summarizing this -
limits development is attachedppendix A The revi w of the 1995 methodology follows In addition
to the parameters limited by this approach, fecal colifo , total nitrogen, total phosphorus, glyphosate
(the primary component df Roundup®), and total resi\acal
e were included as monitoring
requirements since they were viewed to be pollutants of cotream and effluent monitoring for
dissolved oxygen, tZ95,
ature, and conductivity are standafor a large industrial facility
A. BOD livelopment
As in }the BODS monthly average limioped using a combination of the
OCPSF giiidelmes (for Wellman and DuPont) aated Best Available Technology
(BAT) ,allocation (for Monsanto) The same aas used for Monsanto since no
signiZt
Fant production or plant changes have occurred The O PSF allocation was adjusted to
acc for a slight decrease in production at Wellman and DuPo t A spreadsheet m Appendix
A etails the calculations for this allocation The resulting limit is a monthly average of 191
1 s /day, slightly less than the limit of 200 lbs /day in the current permit.
In order to determine the daily maximum BOD5 limit, the Division looked at the long-term
relationship between monthly average BOD values and daily maximums The 1995 permit used
a ratio of 2 to relate the two limits An analysis of the 1999 effluent BOD values indicated an
average ratio of 19 between the two The 1995 ratio of 2 therefore continues to be appropriate,
Fact Sheet
NPDES NC0003719 Renewal
Page 3
Z

�ov �r Tse ��� o
� �5
9 la� /N oV im 7:9
RC1 d J
LA
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IN -AD
,on q
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FA
do 4uz &,QA /0"7 c.&a�/

s)I
retained to avoid backs (particularly given the periodic turbidity problems in the Cape Fear O
River). L7 4� j- ,,a
��-)
ARY OF PROPOSED CHANGES
ng with Division policies the following will be incorporated into the permi/Pont • Annual sampling frequency for all parameters in the OCPSF scan excls and
\cyanide
• ew BOD limits based upon changes in OCPSF flow at Wellman and
• Up A ate description of treatment train
o New Weekly Averlige and Daily Maximum limits are derived from the latest NC/EPA policies
PROPOSED SCHEDME FOR PERMIT ISSUANCE
Draft Permit to Public No's ce• O tober 3, 2001
Permit Scheduled to Issue ovember 26, 2001
NPDES DIVISION CONTAC
If you have questions regarding a of the above information or n the attached permit, please contact
Natalie Sierra at [phone] ext. 551
NAME: DATE:
ENCLOSURES:
• DRAFT PERMIT
• APPENDIX A. DATA AND METHODOLOB US:
• APPENDIX B. REASONABLE POTENTIAL A
• APPENDIX C. FAYETTEVILLE REGIONAL O,
• APPENDIX D. INSTREAM MONITORING DTA
REGIONAL OFFICE COMMENTS
NAME:
FOR PERMIT DEVELOPMENT
STAFF REPORT AND GKPR DATA
OPLOTS
DATE:
SUPERVISOR: DATE:_
Fact Sheet
NPDES NC0003719 Renewal
Page 5

Primary pollutant analysis results for Duke Energy's Riverbend Steam Plant
NC0004961
Outfall 002
Parameter of concern
Bromide Aluminum, Barium Boron Iron rg. Magnesium Molybdenum Manganese Antimony, Arsenic
(mg/L) I (mg/L) (mg/L) ° (mg/L) (mg/L) no (mg/L) (mg/L) (mg/L) (ug/L) (ug/L)
Actual concentration 29 0.168 0 269 0 367 0.58 247 0 079 0.016 10.6 148.4
Allowable concentration not a POC 75.00 10 not a POC 10 not a POC not a POC 2 not a POC 500
Parameter of concern
Sulfate
Copper
Nickel Selenium
Zinc
Chromium Cadmium
(mg/L)
(mg/1)
(ug/L) (ug/L)
(mg/L)
(ug/L) (ug/L)
Actual concentration 538 001 369 49 0.008 3.29 0.98
Allowable concentration 2500 07 250 50 0.5 500 20
r�
, 1,
red font indicates that all Conc Based upon EPA Rec Criteria
fields in bold (no highlighting) indicate that concentration detected is around ambient or tap water values (conversation with Roy Byrd, 10/24/01)
fields with highlighting indicate those parameters that will require periodic monitoring to ensure that the discharge has no impact on the water quality of the receiving stream

Re Balanced and Indig Populations
Subject: Re: Balanced and Indig. Populations
Date: Tue, 20 Nov 2001 14 32:18 -0500
From: Trish MacPherson <[e-mail]>
Organization: DWQ
To: Natalie Sierra <Natalie Sierra @ncmall.net>
I must have left Dave a voice mail just before you sent this email.
Your approach sounds fine. I don't think we believe there are any major
problems with Dan R, Lake Wylie or Mountain Island Lake, though Dave
Lenat thinks Belews Lake benthos still show selenium impacts, but would
like to get a supplemental report from Duke that provide criteria for
deciding if balanced and indigenous, address the concerns noted in the
revised attached comments, and their response to the additional analyses
we suggest. I don't think permit changes are in order -mainly we just
think they could do a lot better job presenting and analyzing the data
they have, and need to have criteria to compare it to in order to
justify the balanced and indigenous statements. Can I keep the reports
you sent? Of the two Coleen sent me, the other copies went to "Shannon"
and "Larry C".
Natalie Sierra wrote:
> Trish-
> Since e-mail was temperamental last week, I was unsure as to whether you
> received my note. I talked it over with Dave and the way we'd like to
> handle it is to send your unit's comments to Duke so that they can
> review those and improve upon future reports. In the meantime, we will
> discuss internally any permit changes that ought to result from the
> assessment of the Duke reports.
> Please let me know if this sounds OK.
> Thanks,
> Natalie
Name: Duke bal indig comments.doc
Duke bal indig comments.doc Type: Microsoft Word Document (application/msword)
Encoding: base64
Download Status: Not downloaded with message
1 of 1 11/27/01 10 52 AM

Review of "Assessment of Balanced and Indigenous Populations in Mountain Island Lake Near
Riverbend Steam Station", Duke Power, January 2001.
Benthos and Chemistry:
Mountain Island Lake has a fairly short retention time due high flow and shallow depths,
sometimes behaving more like a river than a reservoir. There appears to be great variation
between stations and between years, which complicates any analysis of the effects of the power
plant.
Better -maps are needed to show the location of the Cowan Ford Hydroelectric Station, the intake
and discharge structures, the location of McDowell Creek, and any other significant sources of
point or non -point source pollution, and the location of the ash basin outfall in relation to
Mountain Island Lake sampling sites. The station identifiers used are confusing.
McDowell Creek arm continues to exhibit symptoms of eutrophication (increased dissolved
oxygen during the summer, greater conductivity as compared with other lake sampling sites,
increased total suspended solids and elevated nutrient values). Chlorophyll a and phytoplankton
samples should be collected throughout the lake to determine the influence of nutrients on
phytoplankton productivy and diversity. The quality and quantity of phytoplankton in Mountain
Island Lake has an impact on the fish community and shifts to noxious blue-green algae in
response to nutrient loading could negatively impact the diversity and health of the fish in the
lake.
It would appear that selenium (Se) is of some concern here, in spite of the short retention time:
What is the history of selenium values. The rest of the water column chemistry shows no
concerns, and most of this could be discontinued, with the exception of the temperature and DO
profiles.
The sediment chemistry data indicates some Se enrichment (esp. at 277.6), but it is hard to make
much sense of this discussion. There should be some comparison of the sediment selenium
values vs. values known to cause problems in other areas (other NC lakes, literature values) The
10 samples/site are treated as replicates, but the presentation of data in Table 3-3 suggest these
were actually transect samples with Se deposition mainly in deeper waters. If this is the case, it
was inappropriate to treat these samples as replicates in the data analysis. If these are not
transect samples, was sampling targeted at a depth where one might expect high deposition?
-Location 277.6 is referred to as "uplake", but the data suggest some selenium deposition in this
area. Can the plume extend to this area under some flow conditions?
The benthos results refer to the uplake location as 277.5. This does not make sense in relation to
the map. The listing of data in appendices is confusing; it would help to list from upstream to
downstream.
Just as in river systems, reservoirs with short retention time are influenced by rainfall/flow This
report needs more information on flow conditions prior to sampling. High flow years might
prevent Se deposition, so we don't know how representative were the years chosen for sediment
analysis. Much of the variation in benthos data also might be related to flow. Was the low taxa

richness at the upland station in 1995 (Table 4-1, pg. 4-11) related to high flow and scour of he
bottom'? Was the higher taxa richness in 1998 related to low flow?
The benthos summary tables should be extended to cover all years of collection, although it is
not necessary to extend the Appendices for these years. -Analysis is limited to taxa richness, but
could be extended to biotic indices or other metrics.
It would make sense to link the selenium and benthic sampling programs.) Target the areas with
the greatest Se deposition, and do midge deformity studies in those areas relative to control sites.
This type of analysis is easy, cheap, and relevant to the problem being investigated. DWQ
would be glad to help Duke biologists plan such a program.
Fisheries:
Table 4-3 -- Why -are threadfin shad conspicuously absent in the winter 1994 -1999 samples?
Appendices Tables B-1 to B-5 (winter sampling) -- showed an attraction to the discharge area
based upon the winter collections as contrasted to the numbers above the discharge. Thus, this
part of the reservoir does not support a natural fish community. When the Units are not
operating, the CPUE and the number of fish collected are less at the discharge than up reservoir
from the discharge. Also, fewer fish are found below the discharge than above the discharge.
These two factors'would imply that the discharge is having an impact on the fish populations at
and below the discharge.
Appendices Table B-7 to B-12 (summer sampling) -- showed fewer fish at the discharge than
above the discharge. This seems to be an avoidance of this part of the reservoir and thus, this
part of the reservoir does not support a natural fish community. And, generally, fewer fish are
found below the discharge than at the discharge. These results would imply that the discharge is
having an impact on the fish populations at and below the discharge.
Spring electrofishing -- Figure 1-1 showed upstream sites (Nos 6-10) are located only around
the bend from the discharge Why weren't the sites located much further away from the
discharge? The sites should have been located above McDowell Creek.
Table 4-4 -- Even with this close p-oximity of the "reference sites" to the discharge, the number
of fish, biomass, and number of species showed greater numbers of all three variables above the
discharge (Site Nos. 6-10) than below the discharge (Site Nos. 1-5). These results would imply
that the discharge is having an impact on the fish populations below the discharge.
What impacts will Hydnlla and its methods of management (chemical and biological control)
have on the fish population of the reservoir? No mention of this is given in the report even
though Hydrilla was known to be in the reservoir prior to January 2001 when the report was
written. What impact will the alewife (another exotic, first collected in 1999) have on the fish
population of the reservoir?

P" Duke
Power.
A Duk, En, R➢ Company
February 6, 2001
Mr. Charles H. Weaver, Jr.
NC DENR/Water Quality/NPDES Unit
1617 Mail Service Center
Raleigh, NC 27699-1617
Subject: Riverbend Steam Station (RSS)
NPDES Permit Renewal NC0004961
Balanced and Indigenous Monitoring Report
Certified 7099 3400 0003 7612 4874
Dear Mr. Weaver:
Duke Power
Group Environment, Health & Safety
MG03A5
13339 Hagers Ferry Road
Huntersville, NC 28078-7929
- _O
'i
l
7� !
!
FEB ' 9 2001
DFNR - 1°�jTER
POIPdT— ( BRANCH
1—J
0111
Enclosed are three copies of the Assessment of Balanced and Indigenous Populations in Mt.
Island Lake near Riverbend Steam Station. This report supports renewal of the NPDES permit
(NC0004961) for RSS that was requested in the recent permit renewal application submitted to
you on January 22, 2001.
If you have any questions concerning this report, please contact Bob Caccia [phone] or
me (704)-875-5961.
Sincerely,
0,���A4-,-
Michael A. Rube
Manager, Water Compliance

5Duke
Powero
A Duke Energy Company
August 29, 2001
Ms. Natalie Sierra
North Carolina Department of Environment and
Natural Resources
NPDES Unit
1618 Mail Service Center
Raleigh, NC 27699-1618
SUBJECT: Addendum to the NPDES Permit Renewal Supplement
Riverbend Steam Station NPDES Permit # NC0004961
Record Number: NC -005157
Certified: 7000 1670 0001 5505 9716
Dear Ms. Sierra
Duke Power
Group Environment, Health & Safety
MG03A5 --\
13339-�a� erry Road
Huntersv� O�8078-7929
G
O \
d�
Riverbend Steam Station uses CO2 for control of pH during an alga bloom at Outfall
#002. The description of this process was inadvertently left out of the supplemental.
Attached is a copy of the addendum (notice there are 3 pages due to page numbering
changes)
If you need further information, please contact John Mease at [phone].
Sincerely,
Mt4hj Arm
Michael A Ruhe, Manager
Water Compliance
cc- Mike Parker — NCDENR, Mooresville Regional Office

Riverbend Steam Station, Gaston County
NPDES Permit NO NC0004961
Page 4 of 12
Outfall 002 - Ash Basin
The ash basin at RB accommodates flows from the yard drain sump, boiler room sump, ash
removal system and non -point source storm water. Total average influent from these sources
combined is approximately 6 MGD. At times, due to unit loads, rainfall, evaporation and seepage
of ash basin ponds, the amount of effluent may be quite different than influent volumes.
CO2 injection Treatment - During warm periods of the year, algae blooms occur in the ash basin
causing pH leverls to rise. A CO2 system is utilized during these events to maitain the pH level
below 9.0 standard units.
Acid Injection System - An acid injection system utilizing 78 — 80% sulfuric acid may be installed
and used as back-up to the CO2 system for pH adjustment.
Sodium Hydroxide System - A sodium hydroxide injection system utilizing 50 % sodium
hydroxide may be installed and used for low pH treatment.
Yard -Drain Sump
The yard drain sump is a large concrete structure that has four level controlled pumps that direct
wastewater from RB 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 preselected period the
controls are changed so that different pumps are utilized.
The yard drain sump collects wastewater from many sources, such as, sanitary system,
groundwater remediation system, and turbine room sumps. It collects once through non -contact
cooling water from the induced draft (ID) fan motors and the preheater bearings located in the
stacks. The yard drain sump also collects storm water runoff from the coal pile, rail access,
powerhouse roof and paving. Groundwater from a foundation drainage system under the track
hopper is also intermittently discharged to the yard drain sump. The combined average flow from
all sources tied to the yard drain sump is approximately 1.4 MGD.
Sanitary System
Plant sanitary wastes are treated by a series of three 4,000 gallon septic tanks in parallel and a
1,200 gallon holding tank. Sanitary effluent is pumped from the discharge chamber of the
septic tanks to the ash basin via the yard drain sump for final treatment. The sanitary waste
system is designed for 12,500 gallons per day. This design was based on a maximum of 300
and an average of 150 people at the site. Based on annual data the average daily flow to the
yard drain sump has been approximately 0.006 MGD.
The sanitary system accommodates wastewater flow from the following sources:
• general plant sanitary wastewater
• chemical makeup tanks and drum rinsate (Intermittent rinse water containing small amounts
of aluminum sulfate, sodium hydroxide, hydrazine, ammonium hydroxide)
• laboratory drains (Small amounts of laboratory chemicals used to test wastewater effluents
and high purity boiler water)
• office trailer sanitary wastewater.
January, 01

Riverbend Steam Station, Gaston County
NPDES Permit N0. NC0004961
Page 5 of 12
GroundWater Remediation System
This system was installed in 1992. Groundwater is pumped through an oil water separator and
then to the turbine room sump. Trace amounts of volatile organic compounds may be in this
wastewater, such as naphthalene, chrysene, MTBE, and bis(2-ethylhexyl)phthalate.� The
average daily flow from this system is (2 gpm) approximately 0.003 MGD. A revised
groundwater corrective action plan has been submitted to NCDENR that specifies a system
capable of 20 gpm. Therefore, the groundwater remediation system is capable of 0.03 MGD.
Turbine Room Sumps
The turbine room sumps collect approximately 1 MGD of wastewater via a network of floor
drains from intermittent sources listed below:
• Condensate from the feed water system (seal water, valve and pump leakage, cooling water,
vents)
• Equipment cooling water, i.e. air compressors
• Floor wash water containing -janitorial products
• Boiler room sump overflow
• Emergency fire fighting water
• Chiller condensates.
ID Fan and Preheater Bearing Cooling Water
Once through non -contact cooling water is supplied to the ID Fan motor and preheater
bearings to remove excess heat. The rate of flow through these two pieces of equipment
which discharges to the yard drain sump is approximately 0.03 MGD.
Storm Water run-off
The yard drain collects storm water runoff from the coal pile, rail access, powerhouse roofs and
paving around the powerhouse and pumps it to the ash basin. A total of 21.8 acres drain to the
yard sump with an average daily runoff estimated at 0.04 MGD. The average daily runoff is
calculated based on an annual rainfall of 47 inches with 1.0 and 0.5 run-off coefficients applied
appropriately. Trace amounts of oil and grease may be present in the first flush of storm water.
Coal Pile Run-off
The coal pile covers an area of approximately 9 acres with an estimated storm water
run-off of 0.023 MGD. The coal pile runoff drains by gravity to the yard -drain sump
and is then pumped to the ash basin.
Rail Access Run-off
The rail access area where significant coal handling activities occur is approximately
2.5 acres. An estimate of storm water run-off from this area is 0.004 MGD. Storm
water drains by gravity from this area to the yard drain sump.
Powerhouse Roof, Paving and Hard -packed Gravel Areas
The roof of the powerhouse, paving and hard -packed gravel areas around the
powerhouse collect storm water that is drained to the yard drain sump. Trace
amounts of oil and grease may be present in the first flush of storm water. With an
area of approximately 6.3 acres an estimate of storm water run-off is 0.01 MGD.
January, 01

Riverbend Steam Station, Gaston County
NPDES Permit NO NC0004961
Page 6 of 12
Track Hopper Sump
This sump collects groundwater from a foundation drain system underneath the track hopper.
The flow is usually intermittent, and the pump capacity is 100 gpm MGD. On a daily basis it is
estimated that the run time is 50% which would correspond to a flow of 0.05 MGD.
Boiler Room Sumps
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:
• Filtered Water System to the Old End Pit Sump
The filtered water treatment system at RB consists of a clarifier, five gravity filters, two
activated carbon filters, RO system and one set of demineralizers. Wastewater and filter
media from the filtered water system (except demineralizer wastewater which goes to the
boiler room sump) is drained to what RB commonly refers to as the "Old End Pit Sump".
From the pit sump the wastewater is pumped to the Boiler Room Sump.
Clarifier
The clarifier utilizes typical water treatment chemicals such as, aluminum sulfate,
sodium hydroxide, and calcium hypochlorite for the primary treatment of raw water.
The sedimentation wastes collected in the clarifier consists of solids that were
suspended in the service water plus aluminum hydroxide precipitate formed as a result
of adding aluminum sulfate (alum) and sodium hydroxide. The quantity of alum used
per year is approximately 1320 gal/yr. The total amount of caustic is roughly half the
amount of alum (660 gal/yr NaOH). The average volume of water required for
desludging the clarifier is approximately 0.002 MGD. These sedimentation wastes
along with dilute water treatment chemicals and by-products are piped to a floor drain
which flows to the old end pit sump where they are drained to the 4 and 5 boiler room
sump then to the ash basin.
Gravity Filters
There are five gravity filters composed of anthracite (coal) which follow the clarifier in
the water treatment process. Normally, one of these filters is backwashed each day.
Approximately 0.002 MGD of backwash water is required for each filter. This
wastewater flows through floor drains to the old end pit sump -which pumps to the yard
drain sump. The anthracite filter is changed on an as needed basis with the spent
filter media being sluiced to the ash basin via the boiler room sump.
Activated Carbon Filters
The filtered water system includes two activated carbon filters. These filters are
typically backwashed once a month. The flow of water required to backwash one of
these filters is four hours at 100-120 gallons per minute. The backwash flows to the
#6 and #7 turbine room sump and is pumped to the yard drain sump. Approximately
80 ft3 of activated carbon is replaced yearly with the spent carbon sluiced to the ash
basin via the boiler room sump.
Reverse Osmosis (RO) Prefilters
There is one RO prefilter vessel containing 21 - 3 micron cartridge filters which are
used to filter suspended solids. Cartridges are changed out every 1-2 months.
January, 01

PDuke
ohftwern
A Duke Energy Company
July 5, 2001
Mr. Mike Myers
North Carolina Department of Environment and
Natural Resources
NPDES Unit
1618 Mail Service Center
Raleigh, NC 27699-1618
SUBJECT: Vehicle Rinse
Riverbend Steam Station NPDES Permit # NC0004961
Record Number- NC -005157
Certified: 7000 1670 0001 5505 9747
Dear Mr. Myers:
Duke Power
Group Environment, Health & Safety
MG03A5
13339 Hagers Ferry Road
Huntersville, NC 28078-7929
Per a phone conversation on July 3, 2001 between you and John Mease, of Duke
Power, Riverbend Steam Station requests approval for the addition of a vehicle rinse
down area. As agreed, the approval will be made during the NPDES permit renewal
process, which is presently under review by the State. Attached is a copy of the
addendum to the permit renewal application supplement.
The vehicle rinse will use service (raw) water and the effluent will be sent to the ash
basin (NPDES Outfall #002). No soaps will be used at the vehicle rinse area.
If you need further information, please contact John Mease at [phone].
Sincerely,
M;chael A. Ruhe, Manager
Water Compliance
cc: Mike Parker — NCDENR, Mooresville Regional Office
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Per a phone conversation on July 3, 2001 between you and John Mease, of Duke
Power, Riverbend Steam Station requests approval for the addition of a vehicle rinse
down area. As agreed, the approval will be made during the NPDES permit renewal
process, which is presently under review by the State. Attached is a copy of the
addendum to the permit renewal application supplement.
The vehicle rinse will use service (raw) water and the effluent will be sent to the ash
basin (NPDES Outfall #002). No soaps will be used at the vehicle rinse area.
If you need further information, please contact John Mease at [phone].
Sincerely,
M;chael A. Ruhe, Manager
Water Compliance
cc: Mike Parker — NCDENR, Mooresville Regional Office

Riverbend Steam Station, Gaston County
NPDES Permit NO NC0004961
Page 4 of 12
Outfall 002 - Ash Basin
The ash basin at RB accommodates flows from the yard drain sump, boiler room sump, ash
removal system and non -point source storm water. Total average influent from these sources
combined is approximately 6 MGD. At times, due to unit loads, rainfall, evaporation and seepage
of ash basin ponds, the amount of effluent may be quite different than influent volumes.
Yard -Drain Sump
The yard drain sump is a large concrete structure that has four level controlled pumps that direct
wastewater from RB 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 preselected period the
controls are changed so that different pumps are utilized.
The yard drain sump collects wastewater from many sources, such as, sanitary system,
groundwater remediation system, and turbine room sumps. It collects once through non -contact
cooling water from the induced draft (ID) fan motors and the preheater bearings located in the
stacks. The yard drain sump also collects storm water runoff from the coal pile, rail access,
powerhouse roof and paving. Groundwater from a foundation drainage system under the track
hopper is also intermittently discharged to the yard drain sump. The combined average flow from
all sources tied to the yard drain sump is approximately 1.4 MGD.
Sanitary System
Plant sanitary wastes are treated by a series of three 4,000 gallon septic tanks in parallel and a
1,200 gallon holding tank. Sanitary effluent is pumped from the discharge chamber of the
septic tanks to the ash basin via the yard drain sump for final treatment. The sanitary waste
system is designed for 12,500 gallons per day. This design was based on a maximum of 300
and an average of 150 people at the site. Based on annual data the average daily flow to the
yard drain sump has been approximately 0.006 MGD.
The sanitary system accommodates wastewater flow from the following sources:
• general plant sanitary wastewater
• chemical makeup tanks and drum rinsate (Intermittent rinse water containing small amounts
of aluminum sulfate, sodium hydroxide, hydrazine, ammonium hydroxide)
• laboratory drains (Small amounts of laboratory chemicals used to test wastewater effluents
and high purity boiler water)
• office trailer sanitary wastewater.
GroundWater Remediation System
This system was installed in 1992. Groundwater is pumped through an oil water separator and
then to the turbine room sump. Trace amounts of volatile organic compounds may be in this
wastewater, such as naphthalene, chrysene, MTBE, and bis(2-ethylhexyl)phthalate. The
average daily flow from this system is (2 gpm) approximately 0.003 MGD. A revised
groundwater corrective action plan has been submitted to NCDENR that specifies a system
capable of 20 gpm. Therefore, the groundwater remediation system is capable of 0.03 MGD.
Vehicle Rinse -down Area
Effluent from a vehicle rinse -down area is directed to ash basin. The rinse water contains no
soaps or other additives.
January, 01

Duke
Power.
A Duke Energy Company
January 22, 2001
l� LS Il vI
JAS 2 5 2001 I 1
DENR - WATFR QUAL!-Ty
POINT SOURCE P"
Mr. Charles H. Weaver, Jr.
NC DENR/Water Quality/NPDES Unit
1617 Mail Service Center
Raleigh, North Carolina 27699-1617
Subject: NPDES Permit Renewal, NC0004961
Riverbend Steam Station, Gaston County
File: RB -006121
Certified: 7099 3400 0015 4643 8388
Dear Mr. Weaver:
Duke Power
Group Environment, Health & Safety
MG03A5
13339 Hagers Ferry Road
Huntersville, NC 28078-7929
Duke Energy requests the subject permit be renewed and reissued. The above referenced permit
expires July 31, 2001. As required by North Carolina Administrative Code (15A NCAC
2H.01 05(e)), this permit application for renewal is being submitted at least 180 days prior to
expiration of the current permit.
Please find enclosed in triplicate, the application for renewal, which includes the following items:
• EPA Form 1
• EPA Form 2C - Including Priority Pollutant Analysis
• EPA Form 2E
• Site maps
• Water flow diagram and supplemental information.
Duke Power requests notification that the application is complete.
The following monitoring reductions at outfall #002 are requested based on historical monitoring
data, see attached. The frequencies were determined using the EPA guidelines for
"Performance -Base Reduction of Monitoring Frequencies".
• Deletion of monitoring for oil & grease at outfall #002. Analytical results for the last two
years have all been below detection.
• Reduction of Selenium monitoring from monthly to once/six months.
• Reduction of Nitrogen monitoring from quarterly to once/six months.
The Steam Electric Effluent Guidelines (40 CFR 423) restricts iron and copper, during a chemical
metals cleaning, to 1.0 mg/I above background levels. It is requested that the iron and copper
limitation for Outfall #002 only apply during a chemical metals cleaning.

Riverbend requests a continuation of the current thermal limits. The on-going studies show the
balanced indigenous aquatic community in the Catawba River is being maintained under the
current limits.
Thank you for your assistance with this permitting request. Should you have questions or need
additional information, please contact Susan Robinson at [phone].
Sincerely,
vv�
Michael A Ruhe
Manager, Water Compliance
Attachments
cc w/Attachments: Mr. Rex Gleason, NCDENR, Mooresville, N.C.

Date
Dec -98
Jan -99
Feb -99
Mar -99
Apr -99
May -99
Jun -99
Jul -99
Aug -99
Sep -99
Oct -99
Nov -99
Dec -99
Jan -00
Feb -00
Mar -00
Apr -00
May -00
Jun -00
Jul -00
Aug -00
Sep -00
Oct -00
Nov -00
Riverbend Parameter History December 1998 - November 2000
O&G Selenium Nitrogen
ma/I ua/I ma/I
<1.0
<2.0
<1.0
<2.0
<1.0
<2.0
0.2
<1 0
<2.0
<1 0
2.2
<1.0
<2.0
<0.2
<1.0
<2.0
<1 0
<2.0
<1.0
<2.0
<0.32
<1.0
2.5
<1.0
<2.0
<1.0
<2 0
<0 12
<1.0
<2.00
<1.0
<2.00
<1.0
<2.0
019
<1 0
2.2
<1.0
2.9
<1.0
2.4
0.22
<1.0
3.4
<1.0
2.9
<1.0
4.9
<0.22
<1.0
23
<1.0
2.3
<1.0
<2.0
<0.12
O&G
Average 0.0
Permit Limit 11.0
Water Quality Action Levels
Selenium Nitrogen
1.2 0.076
5.0 1.500

SEWAGE
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O• W E R C 0-M P A N Y
RIVERBEND STEAM STATION
NPDES DISCHARGE POINTS
DRINIGNG WATER WELL
DISCHARGE CANAL
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SCALE IN FEET
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RIVERBEND STEAM STATION
NPDES DISCHARGE POINTS

NPDES Supplemental Information for
Riverbend Steam Station
NPDES Permit No. NC0004961

Riverbend Steam Station, Gaston County
NPDES Permit NO NC0004961
Page 2 of 12
General Information
Riverbend Steam Station (RB) is a coal-fired electric generating plant owned and operated by
Duke Power Company. RB is located at 175 Steam Plant Road, six miles northeast of Mount
Holly, North Carolina.
RB's first three generating units were retired in the late 1970s. Units 4 and 5 are each capable of
generating 94,000 kilowatts of electricity. Units 6 and 7 are rated at 133,000 kilowatts each.
In addition to the coal-fired units, four combustion turbines supply 30,000 kilowatts each for use
during periods of peak demand for electricity. Combustion turbines operate differently from steam
plants. They burn oil or natural gas to heat compressed air, which expands and drives a turbine -
generator to produce electricity
A schematic flow diagram of water use, treatment and discharge is attached A brief narrative
description of the individual waste streams follows.
Outfall 001 - Condenser Cooling Water (CCW)
The CCW system is a once through non -contact cooling water system which removes heat from
the condensers and other selected heat exchangers Raw water from the Catawba River is passed
through condensers and auxiliary equipment on a "once -through" basis to cool equipment and
condense exhaust steam from the turbines
When RB is operating at full power, it is has a design capacity to pump 622 1 MGD of cooling
water through a network of tubes that runs through the condenser and selected heat exchangers
(e.g turbine lube oil cooler, condensate cooler, plant chiller system). This raw water in the
condenser tubes absorbs heat from a closed system of highly purified exhaust steam from the
turbines and converts it back to water. Condensed exhaust steam is then returned to the boilers
and is recycled a number of times. The cooling water is returned to the lake No chemicals are
added and only heat rejected from the condensers and auxiliary equipment is absorbed by the
cooling water, hence the term "once through, non -contact cooling water" is applied.
The condensers tubes are periodically cleaned mechanically. Metal or plastic scrapers are forced
through the tubes to rid them of scale or other deposits.
Januarv, 01

Riverbend Steam Station, Gaston County
NPDES Permit NO NC0004961
Page 3 of 12
Each unit at RB has two CCW pumps The pump capacities are listed below Normal plant
operation of the CCW pumps is based on intake and discharge temperatures and unit load
Further, the units are operated on different computer highways or WDPF control systems to avoid
a system trip that would suddenly reduce production of electricity 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 Multiple control units assure that the entire discharge flow at 001 and the
heated effluent will not suddenly stop
Unit No.
1 -Pump GPM
2 -Pump GPM
1
36,000
72,000
2
36,000
72,000
4
33,500
67,000
5
33,500
67,000
6
38,500
77,000
7
38,500
77,000
Filter Backwash from Raw Water Intake Screening Device
Raw water intake screens are backwashed on an as needed basis Normally, the screens require
backwashing once per twelve hour shift for a period of approximately 20 minutes The water
required for backwashing is supplied by a low pressure service pump with a design capacity of 800
gpm Therefore, the average flow of water used to backwash the screens is 0 032 MGD Should
it become necessary to backwash the screens on a continuous basis the maximum flow would be
1 15 MGD This intake screen backwash is discharged into the condenser cooling water line
downstream of the condensers The debris collected on the screens consists mainly of twigs,
leaves, and other material indigenous to the Catawba River
Intake Tunnel Unwatering Sump
In the event that maintenance activities are needed in the intake tunnels an unwatering sump is
provided to remove water from the tunnel(s) To date this operation has not been performed, but it
is available should the need arise Raw water in the tunnels can be removed by a sump pump to
the discharge side of the condensers which would then exit at outfall 001
Turbine Non -Destructive Testing
Bore sonic testing of turbine rotors is infrequent, approximately once every 5 years A maximum
of 400 gallons of demineralized water mixed with 4 gallons of a corrosion inhibitor, e g Calgon CS,
is used during the testing per unit The mixture is drained and mixed with once through cooling
water downstream of the condensers which discharges at outfall 001
January, 01

Riverbend Steam Station, Gaston County
NPDES Permit NO NC0004961
Page 4 of 12
Outfall 002 - Ash Basin
The ash basin at RB accommodates flows from the yard drain sump, boiler room sump, ash
removal system and non -point source storm water. Total average influent from these sources
combined is approximately 6 MGD At times, due to unit loads, rainfall, evaporation and seepage
of ash basin ponds, the amount of effluent may be quite different than influent volumes.
Yard -Drain Sump
The yard drain sump is a large concrete structure that has four level controlled pumps that direct
wastewater from RB 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 preselected period the
controls are changed so that different pumps are utilized
The yard drain sump collects wastewater from many sources, such as, sanitary system,
groundwater remediation system, and turbine room sumps. It collects once through non -contact
cooling water from the induced draft (ID) fan motors and the preheater bearings located in the
stacks The yard drain sump also collects storm water runoff from the coal pile, rail access,
powerhouse roof and paving. Groundwater from a foundation drainage system under the track
hopper is also intermittently discharged to the yard drain sump. The combined average flow from
all sources tied to the yard drain sump is approximately 1.4 MGD.
Sanitary System
Plant sanitary wastes are treated by a series of three 4,000 gallon septic tanks in parallel and a
1,200 gallon holding tank. Sanitary effluent is pumped from the discharge chamber of the
septic tanks to the ash basin via the yard drain sump for final treatment. The sanitary waste
system is designed for 12,500 gallons per day. This design was based on a maximum of 300
and an average of 150 people at the site. Based on annual data the average daily flow to the
yard drain sump has been approximately 0.006 MGD.
The sanitary system accommodates wastewater flow from the following sources:
• general plant sanitary wastewater
• chemical makeup tanks and drum rinsate (Intermittent rinse water containing small amounts
of aluminum sulfate, sodium hydroxide, hydrazine, ammonium hydroxide)
• laboratory drains (Small amounts of laboratory chemicals used to test wastewater effluents
and high purity boiler water)
• office trailer sanitary wastewater
GroundWater Remediation System
This system was installed in 1992. Groundwater is pumped through an oil water separator and
then to the turbine room sump Trace amounts of volatile organic compounds may be in this
wastewater, such as naphthalene, chrysene, MTBE, and bis(2-ethylhexyl)phthalate. The
average daily flow from this system is (2 gpm) approximately 0.003 MGD A revised
groundwater corrective action plan has been submitted to NCDENR that specifies a system
capable of 20 gpm. Therefore, the groundwater remediation system is capable of 0.03 MGD.
January, 01

Riverbend Steam Station, Gaston County
NPDES Permit NO NC0004961
Page 5 of 12
Turbine Room Sumps
The turbine room sumps collect approximately 1 MGD of wastewater via a network of floor
drains from intermittent sources listed below:
• Condensate from the feed water system (seal water, valve and pump leakage, cooling water,
vents)
• Equipment cooling water, i.e. air compressors
• Floor wash water containing janitorial products
• Boiler room sump overflow
• Emergency fire fighting water
• Chiller condensates
ID Fan and Preheater Bearing Cooling Water
Once through non -contact cooling water is supplied to the ID Fan motor and preheater
bearings to remove excess heat. The rate of flow through these two pieces of equipment
which discharges to the yard drain sump is approximately 0.03 MGD.
Storm Water run-off
The yard drain collects storm water runoff from the coal pile, rail access, powerhouse roofs and
paving around the powerhouse and pumps it to the ash basin. A total of 21.8 acres drain to the
yard sump with an average daily runoff estimated at 0.04 MGD. The average daily runoff is
calculated based on an annual rainfall of 47 inches with 1.0 and 0.5 run-off coefficients applied
appropriately. Trace amounts of oil and grease may be present in the first flush of storm water.
Coal Pile Run-off
The coal pile covers an area of approximately 9 acres with an estimated storm water
run-off of 0.023 MGD The coal pile runoff drains by gravity to the yard -drain sump
and is then pumped to the ash basin
Rail Access Run-off
The rail access area where significant coal handling activities occur is approximately
2 5 acres. An estimate of storm water run-off from this area is 0.004 MGD. Storm
water drains by gravity from this area to the yard drain sump.
Powerhouse Roof, Paving and Hard -packed Gravel Areas
The roof of the powerhouse, paving and hard -packed gravel areas around the
powerhouse collect storm water that is drained to the yard drain sump. Trace
amounts of oil and grease may be present in the first flush of storm water. With an
area of approximately 6.3 acres an estimate of storm water run-off is 0.01 MGD.
Track Hopper Sump
The track hopper sump collects groundwater from a foundation drain system underneath the
track hopper. The flow is usually intermittent, and the pump capacity is 100 gpm MGD. On a
daily basis it is estimated that the run time is 50% which would correspond to a flow of 0.05
MGD.
January, 01

Riverbend Steam Station, Gaston County
NPDES Permit NO NC0004961
Page 6 of 12
Boiler Room Sumps
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:
• Filtered Water System to the Old End Pit Sump
The filtered water treatment system at RB consists of a clarifier, five gravity filters, two
activated carbon filters, RO system and one set of demineralizers Wastewater and filter
media from the filtered water system (except demineralizer wastewater which goes to the
boiler room sump) is drained to what RB commonly refers to as the "Old End Pit Sump".
From the pit sump the wastewater is pumped to the Boiler Room Sump.
Clarifier
The clarifier utilizes typical water treatment chemicals such as, aluminum sulfate,
sodium hydroxide, and calcium hypochlorite for the primary treatment of raw water
The sedimentation wastes collected in the clarifier consists of solids that were
suspended in the service water plus aluminum hydroxide precipitate formed as a result
of adding aluminum sulfate (alum) and sodium hydroxide. The quantity of alum used
per year is approximately 1320 gal/yr. The total amount of caustic is roughly half the
amount of alum (660 gal/yr NaOH). The average volume of water required for
desludging the clarifier is approximately 0.002 MGD These sedimentation wastes
along with dilute water treatment chemicals and by-products are piped to a floor drain
which flows to the old end pit sump where they are drained to the 4 and 5 boiler room
sump then to the ash basin
Gravity Filters
There are five gravity filters composed of anthracite (coal) which follow the clarifier in
the water treatment process Normally, one of these filters is backwashed each day.
Approximately 0 002 MGD of backwash water is required for each filter. This
wastewater flows through floor drains to the old end pit sump which pumps to the yard
drain sump. The anthracite filter is changed on an as needed basis with the spent
filter media being sluiced to the ash basin via the boiler room sump
Activated Carbon Filters
The filtered water system includes two activated carbon filters. These filters are
typically backwashed once a month The flow of water required to backwash one of
these filters is four hours at 100-120 gallons per minute The backwash flows to the
#6 and #7 turbine room sump and is pumped to the yard drain sump. Approximately
80 ft3 of activated carbon is replaced yearly with the spent carbon sluiced to the ash
basin via the boiler room sump
Reverse Osmosis (RO) Prefilters
There is one RO prefilter vessel containing 21 - 3 micron cartridge filters which are
used to filter suspended solids. Cartridges are changed out every 1-2 months
January, 01

Riverbend Steam Station, Gaston County
NPDES Permit NO NC0004961
Page 7 of 12
Reverse Osmosis Unit
A RO unit is used to decrease the conductivity in the make-up water, thereby
increasing the efficiency of the demineralizers and reducing the amount of annual
chemicals needed for demineralizer regeneration. During operation, the unit has a
continual blowdown of 50 gal/min which is discharged to the ash basin The RO unit is
cleaned on a quarterly basis with the waste going to the 6&7 sump and then to the ash
basin During cleaning, approximately 30 lbs of the cleaner OSMO AD -20 containing
sulfamic acid, citric acid and sodium lauryl sulfate is used. Also used is a generic
cleaner consisting of tri -sodium laurylsulfate and sulfuric acid with approximately 400
gallons of wastewater going to the ash basin.
Demineralizer regeneration wastewater
The demineralizers consist of 2 mixed -bed cells which supply make-up water to the
boilers and other closed systems. Normal plant operation requires that only one
demineralizer cell operates at a time. Each cell has a capacity of 120 gpm
Each cell is regenerated approximately 20 times per year. Each year RB will use an
estimated 800 gallons of 100% caustic and 400 gallons of 93% sulfuric acid for
demineralizer regenerations An average diluted waste chemical and rinse flow is
approximately 0.004 MGD. The diluted acid and caustic are discharged from the cell
simultaneously through the same header for neutralization purposes The
regeneration wastes flow to the #9 and #10 boiler room sump, to the yard drain sump
and then is pumped to the ash basin The useful life of the resin varies and when
deemed replacement is needed the spent resin is sluiced to the ash basin.
. Coal pulverizing mill cooling water (trace oil and grease)
• Closed system drainage, cleanings, testing containing:
Corrosion inhibitors, e g Calgon CS and MCS plus2, Biocides, e g Calgon H-300 and H-510, Bulab
6002, Cleanings, e g small heat exchangers, Dispersant, e g polyacrylamide, Wetting agent, e g
sodium lauryl sulfate, Detergent, e g tri -sodium phosphate, Leak testing, e g 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 containing janitorial cleaners
• Emergency fire fighting water
• Ash removal system overflow
January, 01

Riverbend Steam Station, Gaston County
NPDES Permit NO NC0004961
Page 8 of 12
. Boiler blowdown
Primarily at unit startup and until water chemistry stabilizes the blowdown from the boilers is
allowed to flash in a blowdown tank. After water chemistry has stabilized the blowdown
condensate flow is small. The condensate is drained to the boiler room sumps. Trace
amounts of hydrazine, ammonia, and silica oxide is present in the condensate. During
normal operation Boilers #7 and #8 blowdown at an average rate of 1000 lbs. of steam per
hour. Boilers #9 and #10 blowdown at an average rate of 1000 lbs. of steam per hour. The
combined condensate flow from blowdown amounts to an average of approximately 0.005
MGD. This flow is routed to the boiler room sump and then to the ash basin A significant
portion of this blowdown steam is vented to the atmosphere
• Chemical Cleaning of Boilers
Boilers #7, #8, #9 and #10 at RB are chemically cleaned on an as needed basis (Boilers
#146 are retired). Tube inspections are done during outages which indicate when cleaning
needs scheduling. Boilers #7 and #8 are natural circulation boilers and #8 and #9 are
controlled circulation boilers.
The volume of the boilers determines the quantity of chemicals required for a cleaning.
Boilers #7 and #8 each have a water -side volume of 26,300 gallons. The volume of #9 and
#10 boilers is 24,900 gallons each. The total volume of dilute waste chemicals, including
rinses, discharged from #7 or #8 boilers during a chemical cleaning is 365,000 gallons. The
total volume of diluted waste chemicals drained from #9 or #10 amounts to 275,000 gallons.
These wastes are drained to the boiler room sump which pumps directly to the ash basin.
Immediately prior to the beginning of a boiler cleaning, additional stop logs are added to the
ash basin discharge structure. This assures longer retention time of the chemical wastes
for proper treatment through dilution, neutralization, precipitation, and ion -exchange as
documented in the Ash Basin Equivalency Demonstration (October 1976). Chemicals and
approximate amounts required to clean the boilers are listed below:
CLEANING CHEMICALS AMOUNT USED PER UNIT
1s' Stage Boiler #7 or #8 Boiler #9 or #10
Sodium Bromate 550 Ib 550 Ib
Ammonium Carbonate 1000 Ib 1000 Ib
*Ammonium Hydroxide 850 gal 850 gal
(26°Be')
2nd Stage (Iron Removal Solution)
Boiler #7 or #8
Boiler #9 or #10
*Hydrochloric Acid (31 5%) (20013e')
3600 gal
3400 gal
*Ammonium Bifluonde (0 5%)
1100 Ib
1050 Ib
Copper Complexer (0 75%)
1660 Ib
1630 Ib
Thiourea or equivalent
Sodium Carbonate
3000 Ib
3200 Ib
Citric Acid
300 Ib
200 Ib
Alkaline Boilouts (only after mayor boder tube work) Boiler #7 or #8
Boiler #9 or #10
Soda Ash
2000 Ib
2000 Ib
Triton X-100 Detergent (0 5%)
10 gal
10 gal
Antifoam Agent (0 025%)
5 gal
5 gal
January, 01

Riverbend Steam Station, Gaston County
NPDES Permit NO NC0004961
Page 9 of 12
*These chemicals are present in amounts greater than the reportable quantity as identified
under the Comprehensive Environmental Response, Compensation, and Liability Act
(CERCLA) If a spill of these chemicals did occur it would in most cases be sent to the ash
basin where treatment would occur.
Ash Removal System
RB utilizes electrostatic precipitators as its air pollution control devices. The fly ash captured in
these precipitators is water -sluiced to the ash basin. Bottom ash from the boilers is also water -
sluiced to the ash basin. Approximately 3 MGD of water is required for this purpose.
Electrostatic precipitators at RB 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.
Storm Water
Non -point sources of storm water which drain to the ash basin include a pond area of 77.3 acres
and an upgradient watershed area of 21.4 acres. The estimate for storm water run-off is based on
forty-seven (47) inches of rain per year with a 1 0 and 0.5 run-off coefficient for the pond area and
upgradient watershed respectively. The average non -point source storm water input for the ash
basin is estimated at 0.31 MGD.
Outfall 002A - Yard -drain Sump Overflow
An overflow pipe that directs flow from the sump to the ground was included in the construction of
the yard sumps. This was done to prevent submergence and damage of the pump motors within
the sumps in the event that all pumps failed or redundant power supply lines could not be restored
in a timely manner. If enough water overflows, the waste could potentially get to the Catawba
River; This has occurred infrequently (approximately once in the past 5 years). Observations and
monitoring of effluent during events of 15 to 30 minute duration have indicated no noticeable
impact to water quality.
Spill Prevention
Oil Storage
Riverbend Steam Station presently has four above ground oil storage tanks - one 4,250,000 gal
fuel oil tank, one 27,000 gal. light -off fuel oil tank, one 20,000 gal. mineral oil storage tank, and
one 2,000 gal. used oil storage tank
All above ground tanks have secondary containment provided which are capable of containing the
entire contents of the tank. An oil trap tank is located in the drainage area of the 4.25 million
gallon oil tank as an added precaution.
All oil storage facilities are presently covered under Spill Prevention Control and Countermeasure
Plans (SPCC), as well as a site Facility Response Plan (FRP)
January, 01

Riverbend Steam Station, Gaston County
NPDES Permit NO NC0004961
Page 10 of 12
Storm Water
RB has several storm water outfalls that discharge to the Catawba River. RB was included in the
group application submitted to the Environmental Protection Agency in March of 1991.
Hazardous and Toxic Substances
Hazardous and Toxic Substances Table 2c- 3
At Riverbend Steam Station, the potential for toxic and hazardous substances being discharged is
very low. In reference to Item V -D of Form 2-C, the substances identified under Table 2c-3 that
may be in the discharge are as follows- Acetaldehyde, Aniline, Asbestos, Benzoyl Chloride, Butyl
Acetate, Cresol, Cyclohexane, Cyclohexanone, Epichlorohydrin, Formaldehyde, Monoethylamine,
Naphthenic Acid, Pyrethrins, Styrene, Triethanolamine, Vanadium, Vinyl Acetate, Xylene and
Zirconium
Other - During the course of the year products such as commercial cleaners and laboratory
reagents may be purchased which contain very low levels of a substance found in Table 2c-3. It is
not anticipated that these products will impact the ash basin's capacity to comply with its toxicity
limits, since their concentrations are extremely low.
40 CFR 117 and CERCLA Hazardous Substances
The following table identifies hazardous substances located on-site that may be released to the
ash basin during a spill in quantities equal to or greater than the reportable quantity (RQ) levels as
referenced in 40 CFR 117, 302 and 355 This list is being provided in order to qualify for the spill
reportability exemption provided under 40 CFR 117 and the Comprehensive Environmental
Response Compensation and Liability Act (CERCLA). These values below represent the
maximum quantities on-site that could be released at one time and sent to the ash basin. They do
not reflect quantities that are discharged through typical use
Substance
Quantity
Source
Benzene
179
Oil Storage Tank
Hydrazine
304
Warehouse
Sodium hydroxide
11994
Tank
Sulfuric Acid
3211
Bulk Storage Tank
Riverbend Steam Station 316(a) Determination
Duke Power Company's operating experience during the past five years under the thermal
limitations imposed in NPDES Permit No. NC#0004961 substantiates EPA's 316(a) determination
(May 1975) for Riverbend 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 "
In Duke's judgement the operating characteristics of the station have a minimal effect on the
aquatic environment of Mountain Island Lake The character of the thermal discharge has not
changed since the original 316(a) determination Accordingly, Duke requests that the thermal
limitations as modified in the present permit be continued
January, 01

Riverbend Steam Station, Gaston County
NPDES Permit NO NC0004961
Page 11 of 12
Ash Basin Capacity
Part III Special Condition L, of the existing NPDES permit for RB requires the permittee to provide and
maintain at all times a minimum free water volume (between the top of the sediment level and the
minimum discharge elevation) 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
Free water volume of RB ash basin:
• Estimate of runoff from 10yr/24 hr storm
Natural drainage area of ash basin 98.7 acres
Powerhouse yard area 21.8 acres
Precipitation from 10yr/24 hr storm 5 inches
Total storm water runoff to ash basin 50.21 Ac -ft
• Estimate max 24 hr dry weather waste stream discharging to ash basin
From station records, maximum recorded ash basin discharge (obtained weekly) 10.66 MGD
For conservatism, increase maximum discharge recorded at station by 10% 35.99 Ac -ft
Free Water Volume = 50.21 + 35.99 = 86.2 Ac -ft
Estimate quantity of solids (ash) to be discharged to ash basin during life of permit
(ref PROMOD analysis for base coal consumption dated 2/21/94)
Time Period
Actual or
Estimated Coal
Consumption
(1000's tons)
Assumed
Ash
%
Estimated Ash
Production
(1000's tons)
Estimated Ash
Production
(Ac -ft)
06/01/1995 - 12/31/1995
238
815
1991
1662
1996
725
917
6643
5546
1997
684
897
61 38
51 24
1998
633
989
6262
5227
1999
617
992
61 22
51 11
01/01/2000-11/30/2000
872
971
8465
7067
12/01/2000-12/31/2000
80
971
777
648
2001
1185
900
10665
8903
2002
1156
900
10406
8687
Total
6191
57469
47975
Estimate of total storage volume required through 2002 479.7 + 86.2 - 295.5 = 270.4 Ac -ft.
As of 6/1/95 survey, the estimate of total ash basin water volume
Primary cell water volume 303.7 Ac -ft
Secondary cell water volume 378.3 Ac -ft
Estimate of total ash basin water volume = 303.7 + 378.3 = 682.0 Ac -ft
Volume required = 270.4 Ac -ft < 682.0 Ac -ft
Conclusion: The RB ash basin has sufficient capacity through the year 2002 The basin capacity will be
recertified by the end of the year 2002
January, 01

Catawba
Intake Screen Backwash
River
Catawba
Plant Chiller System
River
Catawba_
Turbine Lube Oil Coolers
River
Catawba
Condensate Coolers
River
Catawba
Exhaust Steam
River ♦
Condensers
Catawba♦
Intake Tunnel Unwatennc
River
sump
Catawba
River
Riverbend Steam Station
SW from Pond areas"
u radient watersheds 0,31 MGD
atawba Gravity_filter BW & Clanfier
River Filtered Water System slud e Old End Pit Sump
0 004MGD
Demin system Boiler Rm Sump
DW System (groundwater)
January 2001
iem Makeup I ar
Drum Rinsate
Lab Drains
ry
Riverbend Steam Station, Gaston County
NPDES Permit No NC0004961
Page 12, of 12
Ash Sluice System
3 MGD
Evaporation &
Seepage 0 5 MGD
MGD Ash Basin """d"
6 MGD
Yard Urain bump 14MGD
+
Sanitary system 0006 MGD
-I Wastewater
Catawba, Preheater Bearing Cooling 0 15 MGD
River' Water
Catawba Induced Draft Fan Cooling
River Water,0 15 MGD-
Mnt Island Lake
(Catawba River)
Mnt Island Lake
Catawba River
t MGD Turbine Rm Sump Misc wastes
I
005 MGD Track Hopper Sump (GW)
1
0 D3 MGD GW Remediation Oil/Water
I Separator
001 MGD SW From Roof Drains &
Paving
—0023 MGD SW From Coal Pile

NA
NMENR
Ms. Angela M. Grooms
Manager, Water Protection
Duke Power
13339 Hagers Ferry Road
Huntersville, North Carolina 28078-7929
Dear Ms. Grooms.
Michael F Easley
Governor
William G Ross, Jr, Secretary
North Carolina Department of Environment and Natural Resources
Kerr T. Stevens, Director
Division of Water Quality
April 25, 2001
Subject: NPDES Permit Modification Correction
Yard Sump Overflows
Allen Steam Station - NC0004979
Rrverbend Steam Station - NC0004961
Dan River Steam Station - NC0003468
Polk County
On May 15, 2000, the Division issued permit modifications to several Duke Power facilities establishing conditions
under which the discharge of sump overflows is authorimd. Three of the modifications contained errors. The attached
permit pages correct the errors identified in your correspondence.
Please find enclosed the corrected permit pages. The corrected pages should be inserted into the respective permit
and the old pages discarded. All other terms and conditions contained in the original permit remain unchanged and in full
effect. This permit correction is issued under the requirements of North Carolina General Statutes 143215.1 and the
Memorandum of Agreement between North Carolina and the U.S. Environmental Protection Agency.
If any parts, measurement frequencies or sampling requirements contained in this permit modification are
unacceptable to you, you have the right to an adjudicatory hearing upon writen request within thirty (30) days following
receipt of this letter. This request must be a written petition conforming to Chapter 150B of the North Carolina General
Statutes, filed with the Office of Administrative Hearings (6714 Mail Service Center, Rdeigh, North Carolina 27699-6714).
Unless such demand is made, this decision shall be final and binding.
If you have any questions concerning this permit modification, please contact Dave Goodrich at (919) 7335083,
extension 517.
Sincerely,
/�� ;W Z
err T. Stevens -
cc: Central Files
Mooresville Regional Office, Water Quality Section
NPDES unit
1617 MAIL SERVICE CENTER, RALEIGH, NORTH CAROLINA 27699-1 61 7 - TELEPHONE [phone]/FAX [phone]
AN EQUAL OPPORTUNITY AFFIRMATIVE ACTION EMPLOYER - 50% RECYCLED/ 10% POST -CONSUMER PAPER
VISIT US ON THE INTERNET AT http //h2o enr State nc us/NPDES

A (3). EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS - DRAFT
Permit No. NC0004961
During the period beginning on the effective date of the permit and lasting until expiration, the Permittee is authorized to discharge from outfall(s) serial number 002A
— Yard Sump Overflows. Such discharges shall be limited and monitored by the Permittee as specified below
EFFLUENT CHARACTERISTICS
DISCHARGE LIMITATIONS
MONITORING REQUIREMENTS�s;: .
Monthly Average Daily Maximum
Measurement
Frequency Sample Type LocationV ,
Flow (BGD)
Episodic Estimate E
PH
Episodic Grab E
Total Suspended Solids
Episodic Grab E
Fecal Coliform (geometric mean)
Episodic Grab E
Iron
See Footnote 2 Grab E
THERE SHALL BE NO DISCHARGE OF FLOATING SOLIDS OR VISIBLE FOAM IN OTHER THAN TRACE AMOUNTS
ALL FLOWS WILL 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 OCCURRENCE WHEN SUMP OVERFLOWS OCCUR FLOR LONGER THAN ONE HOUR ALL SAMPLES SHALL BE OF A REPRESENTATIVE DISCHARGE
NOTES:
I Sample Locations E — Effluent, Effluent sampling shall be conducted at a point upstream of discharge to the receiving stream
2 Sampling for iron is required when TSS is reported as greater than 100 mg/L

Duke
e Power,
A Duke Ene V Company
July 26, 2000
Mr David A Goodrich
NCDENR/NPDES Unit
Water Quality Section
1617 Mail Service Center -
Raleigh, NC 27699-1617
Subject- Permitting Sump Overflow Pipes
Plant Allen Permit No. NC0004979
Dan River Steam _Station Permit No _NC0003468
Riverbend Steam Station Permit No_ N_ C_ 000496.1_ ;
Record # NC -005157
Certified 7099 3400 0003 7612 5802
Dear Mr. Goodrich.
Duke Power
Group Environment, Health, 6- Safety
MG03A5
13339 Hagers Ferry Road
Huntersville, NC 28078-7929
DENR - MATER QUALITY
P0INT SOURCE BRANCH
NPDES permit modifications to the above listed stations were granted per your May 15, 2000,
letter. After reviewing the modified permit pages a number of minor errors were noted Duke
Power requests the permit pages be updated with the changes listed below Please see attached
copies with marked corrections
Allen Steam Station Permit No NC0004979
• The Power House Sump Overflow outfall serial number should be listed as 002B not
as 002A
• On the same outfall page (#002B) Fecal Coliform monitoring is required for overflows
lasting for more than one hour Duke Power requests the Fecal Coliform monitoring
be removed as no sanitary waste goes to the Power House sump
Riverbend Steam Station Permit No NC0004961
• On yard sump overflows outfall serial number 002A the permit number is listed
incorrectly The permit number should be No NC0004961
Dan River Steam Station Permit No NC0003468
• On the Supplement to Effluent Limitations and Monitoring Requirements, conditions
A(20), A(21) and A(22) from the original permit page were omitted on the new permit
page
Should you have questions or need additional information, please contact John Mease at (704)
875-5347
Sincerely,
Angela M Grooms
Manager, Water Protection
rm
cc- Mr Rex Gleason, NCDENR, Mooresville, N.C.
Mr Larry Coble, NCDENR, Winston-Salem, N.C.

A (3). EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS - FINAL
Permit No.-NG0ft346&
During the period beginning on the effective date of the permit and lasting until expiration, the Permittee is authorized to discharge from outfall(s) serial number 002A
— Yard Sump 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 Sample Type Locations
Flow (MGD)
Episodic Estimate E
pH
Episodic Grab E
Total Suspended Solids
Episodic Grab E
Fecal Coliform
Episodic Grab E
Iron
See Footnote 2 Grab E
THERE SHALL BE NO DISCHARGE OF FLOATING SOLIDS OR VISIBLE FOAM IN OTHER l HAN TRACE AA40UNTS
ALL FLOWS WILL BE REPORTED ON MONTHLY DMRS SHOULD NO FLOW OCCUR DURING A GIVEN MONTH THE WORDS "No FLOW" SHOULD BE CLEARLY WRITTEN O\ THE FRONT OF THE DMR
EPISODIC SAMPLING IS REQUIRED PER OCCURRENCE WHEN SUMP OVERFLOWS OCCUR FOR LONGER THAN ONE HOUR ALL SAMPLES SHALL BE OF A REPRESENTATIVE DISCHARGE
NOTES:
I Sample Locations E — Effluent, Effluent sampling shall be conducted at a point upstream of discharge to the receiving stream
2 Sampling for iron is required when TSS is reported as greater than 100 mg/L

Duke
Power.
A Duke Energy Company
December21, 2000
Mr David Goodrich
North Carolina Department of Environment,
Health, and Natural Resources
Division of Water Quality
1617 Mail Service Center
Raleigh, NC
27699-1617
Subject Riverbend Steam Station
NPDES Permit# NCO004961
Ash Basin Capacity Verification
Certified 7099 3400 0001 7791 9853
Dear Mr Goodrich
L")CIve
Duke Power
Group Environment, Health & Safety
MG03A5
13339 Hagers Ferry Road
Huntersville, NC 28078-7929
DEC 2 9 �IQD
DENR - WATER QUALITY
POINT SOURCE BRANCH
Pursuant to the NPDES permit issued for Riverbend Steam Station there is a requirement in the section titled "Part
III OTHER REQUIREMENTS", Special Condition L, to certify that adequate volume exists in the ash basin to
contain all solids expected to be deposited as well as adequate volume for containment of rainfall runoff Please
find attached the ash basin capacity calculationsfor the Duke Powerfacility located in Gaston County.
The attached calculations indicate that the ash basin is projected to have sufficient detention volume through the
year 2002 We recently completed an ash removal project that removed an estimated 354,000 tons of ash from the
primary cell of the Riverbend ash basin Current calculations indicate a need for 270 4 Acre -ft of volume through the
year 2002 and an available volume of 682 0 Acre -ft The current permit expires on July 31, 2001
The calculations are based on,
1 the most recent physical survey of the ash basin which was performed on June 1, 1995,
2 monthly coal consumption data for estimated ash production from June 1, 1995 through November 30,
2000,
3 ENPRO base fuel consumption forecast (dated June, 1997) for ash production projections from
December 1, 2000, through December, 2002, and
4 an in-place density of 55 pounds of ash per cubic foot
There is a provision in the requirement that allows us to certify adequate volume for the term of the permit Based
on the calculations we do not plan to make annual certifications to your office Pnor to the end of the year 2002 we
will submit to your office another ash basin volume verification
Please contact Robert Caccia at [phone] if you have any questions
Respectfully submitted,
k1A vim(
Michael A. Ruhe
Manager, Water Compliance
RWC/GDB
cc: w/attachment- ash basin calculation sheets
Mr Richard Bridgeman NCDEN R -Mooresville Regional Office
Steve Rutledge Riverbend Steam Station

Duke Power Company
Rlverbend Steam Station -Ash Basin Forecasting
2000 Wet Weather Detention Volume Calculation
Determination of Wet Weather Detention Volume Wet Weather Detention Volume is the sum of the
runoff accumulated in the ash basin which results from a 10 -yr 24 -hr storm (assuming 100% runoff)
plus the maximum 24 -hr dry weather waste stream which discharges to the Ash Basin (refer to
NPDES Permit NC0004961)
I Estimate Runoff to the Ash Basin from a 10 -yr 24 -hr storm
1 Natural Drainage Area of Ash Basin =
Station Yard Drainage Area Pumped to Ash Basin =
Total =
2 Precipitation from 10 -yr 24 -hr storm =
3 Total Stormwater Runoff to Ash Basin =
(Assuming 100% runoff)
II Estimated Maximum 24 -hr Dry Weather Waste Stream Discharging to Ash Basin
1 Maximum recorded Ash Basin Discharge =
2 Increase maximum daily disharge by 10% for
conservatism and convert units to acre-feet =
III Wet Weather Detention Volume
Sum of Parts I and II =
98 7 Acres
21 8 Acres
120 5 Acres
5 0 Inches
50 21 Acre-feet
10,660,000 Gallons/day
IV Estimated Quantity of Solids (Ash) to be discharged to Ash Basin During Life of Permit
(Refer to Coal Consumption Data and ENPRO EN9706F1 Output - Base Fuel Consumption
Forecast)
Note NPDES Permit expiration date is7/31/2001
35 98 Acre-feet
86 19 Acre-feet
* Calculation assumes an In-place ash density of 55 lbs per cubic foot
** Assumes 25% of yearly projection is consumed in January and February
RB Wet Weather Det Vol Calc As
1 12/20/00
Actual or
Estimated Coal
Estimated Ash
Estimated Ash
Consumption
Production
Production (Ac
Time Period
(1000's tons)
% Ash
(1000's tons)
ft) *
6/1/1995 -12/31/1995
238
815%
1991
1662
1996
725
917%
6643
5546
1997
684
897%
6138
5124
1998
633
989%
6262
5227
1999
617
992%
6122
51 11
1/1/2000 -11 /30/2000
872
9 71 %
8465
7067
12/1/2000 -12/31/2000
80
9 71 %
777
648
2001
1185
900%
10665
8903
2002
1156
900%
10406
8687
Total
619053
57469
47975
* Calculation assumes an In-place ash density of 55 lbs per cubic foot
** Assumes 25% of yearly projection is consumed in January and February
RB Wet Weather Det Vol Calc As
1 12/20/00

V
VI
Duke Power Company
Riverbend Steam Station - Ash Basin Forecasting
2000 Wet Weather Detention Volume Calculation
Estimated Total Storage Volume Required through 2002
Wet Weather Detention Volume = 86 2 Acre-feet
Estimated Solids to Ash Basin = 479 7 Acre-feet
2000 Ash Removal Project (354,000 tons) _ -295 5 Acre-feet
Total = 270 4 Acre-feet
Results
Available Storage based on most recent basin survey dated 6/1/1995
Primary Cell
303 7 Acre-feet
Secondary Cell
378 3 Acre-feet
Total
682 0 Acre-feet
Required Storage Volume
Through 12/31/2002 =
270 4 Acre-feet
Through 12/31/2001 =
1836 Acre-feet
Based on these calculations, there is sufficient capacity in the ash basin to provide the
retention volume specified in the permit through the year 2002
RB Wet Weather Det Vol Calc As
12/20/00

State of North Carolina
Department of Environment
and Natural Resources
Division of Water Quality
James B. Hunt, Jr., Governor
Bill Holman, Secretary
Kerr T. Stevens, Director
May 15, 2000
Ms Angela M Grooms, Manager
Water Protection
Duke Power
Group Environment, Health cQ Safety
15559 Hagers Ferry Road
Huntersville, North Carolina 28078-7929
NCDENR
NORTH CAROLINA DEPARTMENT OF
ENVIRONMENT AND NATURAL RESOURCES
Subject- NPDES Permit Modification
Dan River — Permit No NC0003468
Allen — Permit No NC0004979
Marshall —Permit No NC0004987
Riverbend — Permit No NC0004961
Dear Nis Grooms
The Division issued NPDES permit numbers NC0005468. NC0004979, NC0004987, and
NC0004961 on April 25, 1997. September 4, 1996, August 31, 1995 and July 29 1996 respectively The
Division has reviewed your request for permit modification at the subject facilities Specifically, you requested
that all sump overflows as outlined in your December 1, 1999 correspondence be permitted as individual
outfalls In accordance with your permit modification request the Division is forwarding herewith
modifications to the subject permits These permit modifications incorporate effluent sampling requirements
for sump overflows in accordance with the permitting strategy developed for Buck Steam Station
Enclosed please find the modified NPDES permit pages These pages should be inserted into the
respective permits and the old ones discarded. These permit modifications are issued pursuant to the
requirements of North Carolina General Statute 145-215 1 and the Memorandum of Agreement between
North Carolina and the U S Environmental Protection Agency dated December 6, 1985
Please take notice that these permits are not transferable Part ll, E 4 addresses the requirements
to be followed in case of change in ownership or control of this discharge These permits do not affect the
legal requirement to obtain other permits which may be required by the Division of Water Quality or permits
required by the Division of Land Resources, Coastal Area Management Act or any other Federal or Local
government permit that may be required
1617 MAIL SERVICE CENTER RALEIGH NORTH CAROLINA 27699-1617 -TELEPHONE [phone]/FAX [phone]
AN EQUAL OPPORTUNITY AFFIRMATIVE ACTION EMPLOYER - 50% RECYCLED/ 10% POST -CONSUMER PAPER

If you have any questions concerning these modifications please contact Mr Mark McIntire at
telephone number [phone], extension 555
Sincerely
/I err T Stevens
Enclosures modified permit pages
Cc Central Files (correspondence letter, modified permit pages)
NPDES Permit Filery(correspondence, letter, modified permit pages)
Mooresville Regional Office (letter, modified permit pages)
Winston-Salem Regional Office (letter, modified permit pages)
Point Source Compliance/Enforcement Unit (letter)

NCDENR/DIVISION OF WATER QUALITY
Water Quality Section/NPDES Unit
October 9, 1998
MEMORANDUM
To. Dave Goodrich
From: Mark McIntire
Subject: Sump Overflows
Duke Power Fossil Plants
I have been in discussions for quite some time with John Mease and Angela Grooms of Duke Power Company regarding
sump overflow issues. NPDES permits for Allen, Buck, Dan River, Marshall, and Riverbend steam stations do not
currently accommodate these overflows_ Our discussions have been aimed at finding a practical, protective way of
handling these situations.
Earlier in the year. I instructed Duke Power to grab a series of eight samples from the sump at Buck Steam Station
over a two week period (these sumps are those that deliver wastewater to the ash basins). Duke collected the samples
and subsequently forwarded the results, attached, to our office on March 27, 1998. The data is indicative of an ash
basin discharge with the exception of relatively high solids and iron_ Incidents of high iron and TSS were likely due to
heavy rains agitating sediment prior to raw water intake.
These sump overflows occur in small volumes and on rare occasions In light of the very high stream flows associated
with the streams into which Duke discharges, the impact from these sump overflows is very likely minimal to zero. As
such, I recommend permitting these sump overflows as a serial numbered outfall with appropriate monitoring installed
typical of that required at ash basin discharges. Furthermore, as these sump overflows are relatively consistent from
facility to facility, I do not think it's necessary to require characterization of the other four facilities. Attached is a
letter to Duke Power to that affect. As this proposition would involve the permitting of an additional outfall, we would
likely need to proceed with the major modification route_ In addition to monitoring for these overflows. I propose that
we require Duke Power to make every reasonable attempt to minimize the occurrence of these overflows. We should
also require Duke to make every reasonable attempt to redirect these overflows to the respective ash basins.
�jC

Y
Re Duke Power Sump Overflow
Subject: Re: Duke Power Sump Overflow...
Date: Mon, 01 May 2000 13.46.41 -0400
From: Larry Coble <larry.coble@ncmail net>
Organization: NC DENR Water Quality
To: Mark McIntire <mark mcintire@ncmail net>
Tlus sounds fine to the WSRO.
Mark McIntire wrote
Gentlemen,
You may remember corresponding with me about sump overflows at Duke
Power fossil plants. Working with Duke Power at Buck Steam Station, we
developed a strategy for permitting the yard sump overflows they were
experiencing. These overflows occur very rarely (perhaps once per year)
and typically involve de minimus flows. However, given the current
legal and third part climate, Duke would like to have these overflows
permitted at Allen, Dan River, Riverbend, and Marshall as well.
As a refresher, we required episodic sampling for pH, TSS, fecal
coliform, and iron. Episodic being defined as any overflow lasting
longer than 1 hour. All overflows will be reported to regional office
staff within the required timeframe. Iron will be analyzed if the TSS
sample is reported as greater than or equal to 100 mg/L. Fecal coliform
will only be required for those yard sumps receiving sanitary
wastewater.
The ultimate goal is to eliminate all overflows completely. Until that
itime, permitting these as outfalls with analytical requirements provides
Duke with a level of comfort in the context of third party litigation
and the Division's new overflow policy.
Let me know if you have concerns regarding this matter. My plan is to
handle these as minor modifications to the fossil plant permits
referenced above.
Thanks for your assistance.
Mark
Mark D. McIntire
Environmental Engineer
NPDES Unit - Division of Water Quality
1617 Mail Service Center
Raleigh, NC 27699-1617
[phone], extension 553
mailto-mark.mcmtire@ncmail net
to (GO wd,
5,
i e-
�
1 of *) 05/09/2000 10 50 AP

Duke
Power,
A Duk, Ay Comps y
December 1, 1999
Mr. David A. Goodrich
NCDENR/NPDES Unit
Water Quality Section
1617 Mail Service Center
Raleigh, NC 27699-1617
Subject: Permitting Sump Overflow Pipes
Plant Allen Permit No. NC0004979
Dan River Steam Station Permit No. NC0003468
Marshall Steam Station Permit No. NCO004987
Riverbend Steam Station Permit No. NC0004961
Record #: NC -005157
Certified: Z 335 554 746
Dear Mr. Goodrich:
Duke Power
Group Environment, Health & Safety
13339 Hagers Ferry Road
Hunrersville, NC 28078-7929
Duke Power requests that the overflow pipes for the yard sumps listed below be
permitted in the same manner as detailed in the draft NPDES permit (NC0004774) for
Buck Steam Station Outfall #002A. That outfall page is attached. Plant Allen's coal yard
sump and Riverbend Steam Station's yard sump are the only sumps containing sanitary
waste. Duke Power requests that only these two sumps be required to monitor for fecal.
Station
Sump
New Outfall Number
Allen
Coal yard
#002A
Power House
#002B
Dan River
Yard
#002A
Marshall
Sump 1
#002A
Sump 2
#0028
Riverbend
Yard
#002A
See the attached site maps for location of the sump overflow discharges. Should you
have questions or need additional information, please contact John Mease at (704) 875-
5347.
Sincerely, '
lJ
Angela M. Grooms I
Manager, Water Protection
frm
cc: Mr. Rex Gleason, NCDENR, Mooresville, N.C.
Mr. Larry Coble, NCDENR, Winston-Salem, N.C. 0�

SUPPLEMENT TO PERMIT COVER SHEET
Duke Power Company
is hereby authorized to:
Permit No NC0004961
Continue to discharge once through cooling water (outfall 001) consisting of intake screen
backwash, and water from plant chiller system, turbine lube oil coolers, condensate coolers,
main turbine steam condensers, and the intake tunnel dewatering sump, ash basin discharge
(outfall 002) and yard sump overflows (outfall 002A) consisting of induced draft fan and pre -
heater bearing cooling water, stormwater from roof drains and paving, treated groundwater,
track hopper sump (groundwater), coal pile runoff, laboratory drain and chemical makeup
tanks and drums rinsate wastes, ash transport water, general plant/trailer sanitary wastewater,
metal cleaning waste, chemical metal cleaning waste, combustion turbine cooling water
discharges, turbine and boiler rooms sumps and stormwater from pond areas and up -gradient
watershed from a facility located at Riverbend Steam Station, Mount Holly, Gaston County
(See Part III of this permit), and
2. Discharge wastewater from said treatment works at the location specified on the attached
map into the Catawba River which is classified WS -IV and B waters in the Catawba River
Basin.

A (3). EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS - FINAL Permit No. NC0005468
During the period beginning on the effective date of the permit and lasting until expiration, the Permittee is authorized to discharge from outfall(s) serial number 002A
— Yard Sump 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 Sample Type Locations
Flow (MGD)
Episodic Estimate E
pH
Episodic Grab E
Total Suspended Solids
Episodic Grab E
Fecal Coliform
Episodic Grab E
Iron
See Footnote 2 Grab E
THERE SHALL BE NO DISCHARGE OF FLOATING SOLIDS OR VISIBLE FOAM IN OTHER THAN TRACE AMOUNTS
ALL FLOWS WILL BE REPORTED ON MONTHLY DMRs SHOULD NO FLOW OCCUR DURING A GIVEN MONTH, THE WORDS "NO FLOW" SHOULD BE CLEARLY WRITTEN ON THE FRONT OF THE DMR
EPISODIC SAMPLING IS REQUIRED PER OCCURRENCE WHEN SUMP OVERI-LOWS OCCUR FOR LONGER THAN ONE HOUR ALL SAMPLES SHALL BE OFA REPRESENTATIVE DISCHARGE
NOTES:
I Sample Locations E — Effluent, Effluent sampling shall be conducted at a point upstream of discharge to the receiving stream
2 Sampling for iron is required when TSS is reported as greater than 100 mg/L

State of North Carolina
Department of Environment
and Natural Resources
Division of Water Quality
James B. Hunt, Jr., Governor
Wayne McDevitt, Secretary
A. Preston Howard, Jr., P.E., Director
October 12, 1998
Ms Angela Grooms
Manager, Water Protection
Duke Power
13339 Hagers Ferry Road
Huntersville, North Carolina 28078-7929
NCDENR
Subject. Sump Overflows
Duke Power Company
NC Fossil Plants
Dear Ms. Grooms_
The Division has reviewed the information submitted by Duke Power regarding sump overflows at
Allen, Buck, Dan River, Marshall, and Riverbend Steam Stations and accepts the characterization conducted at
Buck as adequate for the remaining four facilities due to the similarity of the sump water
It is the Division's recommendation that the NPDES permits for the above mentioned facilities be
modified to accommodate these sump overflows The Division would treat these overflows as an additional
permitted outfall with monitoring requirements indicative of those at the ash basin effluent Additionally, the
Division would ask that Duke Power, wherever possible, minimize these overflows either through collection or
diversion to the ash basin
As this request would involve the installation of an additional permitted outfall into the NPDES
permit, it would be considered a major modification and be subject to all appropriate timelines and Statutory
requirements
Should you have any questions or comments regarding this speculative limits request, please do not
hesitate to contact Mark McIntire at [phone], extension 553.
Sincerely,
David A. Goodrich
Supervisor, NPDES Unit
cc: Central Files (with attachments)
Mooresville Regional Office, Water Quality Section
Winston-Salem Regional Office, Water Quality Section
NPDES Unit Files 6,vith attachmenis)
__-CO004961 _NC0004987, NC0003468, NC0004979
NC0004774
P O Box 29535, Raleigh, North Carolina 27626-0535 Telephone [phone] FAX [phone]
An Equal Opportunity Affirmative Action Employer 50% recycled / 10% post -consumer paper

NCDENR/DIVISION OF WATER QUALITY
Water Quality Section/NPDES Unit
October 9, 1998
MEMORANDUM
To Dave Goodrich
From Mark McIntire
Subject Sump Overflows
Duke Power Fossil Plants
I have been in discussions for quite some time with John Mease and Angela Grooms of Duke Power Company regarding
sump overflow issues NPDES permits for Allen, Buck, Dan River, Marshall, and Riverbend steam stations do not
currently accommodate these overflows Our discussions have been aimed at finding a practical, protective way of
handling these situations
Earlier in the year, I instructed Duke Power to grab a series of eight samples from the sump at Buck Steam Station
over a two week period (these sumps are those that deliver wastewater to the ash basins) Duke collected the samples
and subsequently forwarded the results, attached, to our office on March 27, 1998 The data is indicative of an ash
basin discharge with the exception of relatively high solids and iron Incidents of high iron and TSS were likely due to
heavy rains agitating sediment prior to raw water intake
These sump overflows occur in small volumes and on rare occasions In light of the very high stream flows associated
with the streams into which Duke discharges, the impact from these sump overflows is very likely minimal to zero As
such, I recommend permitting these sump overflows as a serial numbered outfall with appropriate monitoring installed
typical of that required at ash basin discharges Furthermore, as these sump overflows are relatively consistent from
facility to facility, I do not think it's necessary to require characterization of the other four facilities Attached is a
letter to Duke Power to that affect As this proposition would involve the permitting of an additional outfall, we would
likely need to proceed with the major modification route In addition to monitoring for these overflows, I propose that
we require Duke Power to make every reasonable attempt to minimize the occurrence of these overflows We should
also require Duke to make every reasonable attempt to redirect these overflows to the respective ash basins

Mark,
Per our phone call, attached is a list of waste streams at our NC Fossil sites that
have sumps with overflow pipes going to surface waters. Also included is a copy
of the letter (March 27,1998) with the results from the sump characterization
study done at our Buck Steam Station.
Please review this information and let us know what the permitting requirements
would entail.
Thanks for your help with this matter.
John Mease

Sump Waste Streams
Allen Steam Station q� � q
Powerhouse Sump Waste Streams: (Overflows to River)
• Unit # 5 Boiler Room sump:
Floor wash water (O&G)
Boiler seal water
• Unit #3, #4, #5 Induced Draft Motor Bearing Cooling Water
• Unit #3, #4, #5 Air Preheater wash water (iron)
• Unit #3, #41 #5 Checker Plate wash/stormwater (ash)
• Unit #3, #4, #5 Flyash separator Tank overflow (ash)
• Surface drains north of Powerhouse
• 100,000 gallon Fuel Oil Storage Tank containment drain
• Groundwater remediation oil/water separator discharge
Yard Drainage Sump Waste Streams: (Overflows to CY Sump)
• Water Treatment System
Clarifier desludge
Pressure filter backwash
Activated carbon filter backwash
Reverse Osmosis blowdown
Reverse Osmosis Prefilter backwash
Demineralizer/regeneration discharge (neutral)
• Boiler Blowdown (hydrazine)
• Laboratory wastes
• Closed Cooling Water leakage(biocides)
• Turbine NDE Testing discharge (corrosion inhibitor)
• Heat Exchanger cleaning discharge
• Unit #1, #2 Induced Draft Fan Motor Bearing Cooling Water
• Unit #1, #2, #31 #4 Boiler Room Sumps
Floor wash Water
Boiler Seal Water
• Unit #1, #2 Air Preheater Wash Water (iron)
• Chemical make-up tanks and drum rinseate (hydrazine)
• Misc. Janitorial processes
• Misc. stormwater drains

Coal Yard Sump Waste Streams: (Overflows to River)
• Coal Pile Run-off
• Misc. Coal handling Sump Pump Discharges
• Sanitary (septic tank effluent)
• Possible overflow from Yard Drainage Sump
• Misc. stormwater drains
• Buck Steam Station
Yard Sump: (Overflows to the Yadkin River)
• Water Treatment System
Clarifier desludge
Gravity filters backwash
Activated carbon filters backwash
Demineralizer/regeneration discharge (neutral)
• Waterwall blowdown
• Continuous boiler blowdown
• Superheater drain lines
• Yard drains (stormwater)
• Coal pile runoff
• Sanitary waste
• Floor drains
• Sulfuric acid
• Sodium Hydroxide
• Water treatment chemicals
• Hydrazine
• Oil
• Corrosion Inhibitions
• Laboratory Waste
• Oil/water separator discharge
• Microbiocides
• Industrial cleaning products
13

Dan River -� ,W
Yard Sump: (Overflows to the Dan River)
• Yard drains (stormwater)
• Coal pile runoff
• Miscellaneous parking lot oil & gasoline (only leaks or spills
and light maintenance activities)
• Small amounts of flyash from precipitator hopper
maintenance
Marshall e0
Sump 2: (Overflow to Lake Norman)
• Water Treatment System
Clarifier desludge
Gravity filters backwash
Activated carbon filters backwash
Dem ineral izer/regeneration discharge
• Closed system drainage, cleanings, testing
• Boiler seal water
• Miscellaneous system leakage's
• Moisture separators on air compressor precipitators
• Floor wash water
• Pyrite (ash) removal system overflow
• Low volume wastewater
• Chemical makeup tanks and drum rinsate
• Boiler blowdown
• Yard stormwater drains
Sump 1: (Overflow to Lake Norman)
• Coal pile runoff
• Yard stormwater drains
• Turbine room sump overflow

River -bend 4-�6
Yard Sump: (Overflow to Catawba River)
• Water Treatment System
Clarifier desludge
Gravity filters backwash
Activated carbon filters backwash
Demineralizer/regeneration discharge (neutral)
• Boiler Cleaning
• Water treatment chemicals
• Continuous boiler blowdown
• Superheater drain lines
• Yard drains (stormwater)
• Coal pile runoff
• Sanitary waste
• Floor drains
• Sulfuric acid
• Sodium Hydroxide
• Hydrazine
• Oil & gasoline (only from leaks or spills)
• Corrosion Inhibitions
• Laboratory Waste
• Oil/water separator discharge
• Microbiocides
• Industrial cleaning products
• Groundwater sump
• ID fans cooling water
• Chemical makeup tank drain lines
1. Hydrazine
2. Ammonium Hydroxide
3. NaOH
4. Aluminum Sulfate
• Preheater bearing cooling water

P&D,,Poke
ower_
eo.J,E—VC-0.7
March 27, 1998
Mr. Mark McIntire
NPDES Unit
North Carolina Department of Environment and Natural Resources
Division of Water Quality
P. O. Box 29535
Raleigh, NC 27626-0535
Subject: Buck Steam Station
Rowan County
NPDES # NC0004774
Record #: BU -004883
Certified Mail: P 318 140 645
Dear Mr. McIntire:
Duke Power
Group Environment. Health cr Safety
13339 Hagers Ferry Road
Huntersville, NC 28078-7929
Attached are the sample results characterizing the sump used in the waste treatment
system at Buck Steam Station. This characterization was needed in regards to the
possible permitting of the sump's overflow pipe, see attached letter dated March 4,
1998.
As required, the sump was sampled eight times during a two week period on Monday,
Tuesday, Wednesday and Thursday at approximately two o'clock for the requested
parameters. When the samples were collected the sump was operating, receiving the
normal plant waste streams. The two sampling events included normal plant
operations with units on and off line under dry weather and the units on and off line
with heavy rains conditions (coal pile run off).
Should you need additional information, please contact John Mease at (704) 875-
5347.
Sincerely,
A'd, -M
A', -
Angela M. Grooms
Manager, Water Protection
jrm
cc: John Lesley, Mooresville Regional Office NCDENR

Sump Results
Samples Collected 3/2-5/98 and 3/9-12/98
Sampling Date
02 -Mar -98
TSS mg/L
22.0
O&G mg/L
<1.0
SOD mg/L
0.8
Ammonia
mg-N/L
0.21
Total Arsenic
ug/L
<2.0
Total Copper
mg/L
0.038
Total Iron
mg/L
1.613
03 -Mar -98
64.0
<1.0
0.8
0.10
<2.0
0.041
1.826
04 -Mar -98
34.0
<1.0
<2.0
0.08
<2.0
0.061
1.583
05 -Mar -98
34.0
<1.0
<2.0
0.08
<2.0
0.008
1.251
09 -Mar -98
100.0
<1.0
4.2
0.27
<2.0
0.035
5.564
10 -Mar -98
190.0
<1.0
3.1
0.22
4.4
0.023
10.84
11 -Mar -98
168.0
<1.0
2.9 1
0.16
1 3.5 1
0.026 1
6.718
12 -Mar -98
127.0
<1.0
<2.0
0.06
2.4
0.027
4.698
4
Total
Total
Total
Sampling Date
Nitrogen
Phosphorus
Selenium
pH (S.U.)
TemperaturemF
Weather
Unit Status
mg -NIL
mg-P/L
ug/L
02 -Mar -98
0.89
0.097
<2.0
7.35
58.6
No Rain
Off
03 -Mar -98
1.12
0.123
<2.0
8.16
60.3
No Rain
Unit 5 On
04 -Mar -98
0.96
0.100
<2.0
7.44
56.8
No Rain
Unit 5 On
05 -Mar -98
0.85
0.296
<2.0
7.49
56.3
No Rain
Unit 5 On
09 -Mar -98
0.97
0.140
<2.0
6.1
57.2
Heavy Rain
Off
10 -Mar -98
0.69
0.210
<2.0
6.83
61.2
No Rain
I Units 5&6 On
11 -Mar -98
0.96
0.270
<2.0
6.97
55.9
No Rain
Units 5&6 On
12 -Mar -98
1.25
0.170
<2.0
7.28
54.3
No Rain
Units 5&6 On
4

P-ake
Power-
AD.k,F—wC—V-7
4, 1998
Mr. John Lesley
Department of Environment and Natural Resources
Water Quality Section
Mooresville Regional Office
919 North Main Street
Mooresville, NC 28115
Subject: Buck Steam Station
Rowan County •_
NPDES # NC0004774
Record #: BU -004883
Certified Mail: P 399 635 422
Dear Mr. Lesley:
Duke Power
Gmup Envimnmrnt, Heakh d Safay
13339 Hagers Ferry Road
Hunrersville, NC 28078-7929
As per a phone conversation between yourself and John Mease (Duke Power),
John Mease talked to Mr. Mark McIntire (NCDENR, NPDES Unit) regarding the
possible permitting of the sump overflow pipe at Duke Power's Buck Steam
Station.
Mr. McIntire determined the following information would be required before a
decision could be made regarding possible permitting and permit limits on the
overflow pipe:
• Eight discrete samples to be collected in the sump over a two week period on
Monday, Tuesday, Wednesday and Thursday
• Sample for the following parameters:
• Total Suspended Solids
• Oil and Grease
• Biochemical Oxygen Demand -
• Ammonia
• Total Copper
• Total Iron
• Total Arsenic
• Total Selenium
• Total Phosphorus
• Total Nitrogen
• pH
• Temperature