ML051880052

National Pollutant Discharge Elimination System (NPDES) Permit No. SC0004278

ML051880052
Person / Time
Site:	Catawba
Issue date:	06/22/2005
From:	Jamil D Duke Power Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
SC0004278
Download: ML051880052 (75)

Text

{{#Wiki_filter:PWDuke D.M. JAMIL OrPowere Vice President Duke Power Catawba Nuclear Station 4800 Concord Road / CNOI VP York, SC 29745-9635 803 831 4251 803 831 3221 fax June 22, 2005 U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, D.C. 20555

Subject:

Catawba Nuclear Station, Units 1 and 2 Docket Nos. 50413 and 50414 National Pollutant Discharge Elimination System (NPDES) Permit No. SC0004278 The National Pollutant Discharge Elimination System (NPDES) Permit for Discharge to Surface Waters for Catawba Nuclear Station was modified by the State of South Carolina on June 1, 2005. This permit was specifically modified to allow discharge to the nuclear service water pond with the addition of Outfall 006. A copy of the modified NPDES permit is attached. Any questions concerning this report should be directed to Margot Rott at 803.831.3180. Sincerely, Dhiaa M. Jamil Enclosure xc: (* w/o enclosure) W. D. Travers, Regional Administrator, Region II S. E. Peters, NRR Project Manager E. F. Guthrie, Senior Resident Inspector amlo Catawba Nudear Statiofl20th Anniversary www. dukepower. corn 1985-2005

RD H E C PROMOTE PROTECT ROSPER South Carolina Department of Health and Environmental Control ATatiolal PollutantDischarge Elimina t1011 System Permit for Discharge to Surface Waters This Permit Certifies That Duke Energy Corporation Catawba Nuclear Plant has been granted permission to discharge from a facility located at Newport, South Carolina York County to receiving waters named Lake Wylie in accordance with limitations, monitoring requirements and other conditions set forth in Parts I, II, and III hereof. This permit is issued in accordance with the provisions of the Pollution Control Act of South Carolina (S.C. Code Sections 48-1-10 et seq., 1976), Regulation 61-9 and with the provisions of the Federal Clean Water Act (PL 92-500), as amended, 33 U.S.C. 1251 et seq., the "Act." Marion F. aer, r., Dir r Industrial, Agricultural, and Storm Water Permitting Division Bureau of Water Issued: April 30, 2001 Expires: June 30, 2005 Effective: June 1, 2001 Permit No.: SC0004278 Modification: June 1, 2005

A. EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS

1. During the period beginning on the effective date of this permit and lasting through the expiration date, the permittee is authorized to discharge from outfall(s) serial nuriber(s) 001: once through cooling water, nuclear service w~ater, cooling tower blowdown (discharged via internal Outfall 005) and liquid radiological wastes (treated and discharged via internal Outfall 004) to Lake Wylie.

Such discharge shall be limited and monitored by the Permittee as specified below: EFFLUENT CHARACTERISTICS DISCHARGE LIMITATIONS Other Units (Specify) Daily Weekly Monthly Average Average Average MR 0.011 mg/I MONITORING REQUIREMENTS Flow (MGD) Total Residual Chlorine (TRC)B Nitrite (NO2) Copper, total recoverable0 Intake Temperature 0C(CF) Discharge Temperature 'C( 0F) Temperature rise (April-September)

Temperature rise (October-March)

Daily Maximum MR 0.019 mg/I 4.3 mg/I MR MR MR )0F) )0F) Measurement Frequency Daily 1/week 1/occurrence 1/month Daily Daily Daily Daily Sample Type ContinuousA Multiple Grabsc Grab Grab Continuous* Continuous Calculation Calculation MR - --MR: ' ' MR l 5.60C(10.C 7.80C(14.( ASee Part III, Special Condition #14 MR = Monitor and Report 'See Part III, Special Condition #15 & 16 Based on a flow of 73.6 MGD CS66 Part III, Special Condition #17 DSee Part III, Special Condition #23 No chromium and zinc based maintenance chemicals will be allowed in the cooling tower.

a. The pH shall be monitored and reported once per week by'grab sample.

b. There'shall be no discharge of floating solids or visible foam in other than trace amounts; nor, shall the effluent cause a visible sheen on the receiving waters.

c. Samples taken in compliance with the monitoring requirements specified above shall be taken at the following location(s):

The intake temperature shall be monitored at or near the plant intake. All other parameters shall be monitored at or near the point of discharge from Outfall 001 prior to mixing with the receiving waters, unless otherwise specified above. id o5 CD 9a rj (n

a. EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS

2. During the period beginning on the effective date of this permit and lasting through the expiration date, the permittee is authorized to discharge from outfall(s) serial number(s) 002: low volume wastes, miscellaneous dilute wastewater, and chemical metal cleaning wastes to Lake Wylie.-

Such discharge shall be limited and monitored by the Permittee as specified below: EFFLUENT CHARACTERISTICS;- DISCHARGE LIMITATIONS MONlTO (lbs/day) ' Other Units (Specify) nthly MDaily. u Monthly MDaily Average Maximum Average Maximum IRING REQUIREMENTS Flow (MGD) Total Residual Chlorine (TRC)B Biochemical Oxygen Demand (5-day) Oil and Grease Total Suspended Solids Copper, total Iron, total Hydrazine Nitrite (NO2) 0.011 mg/I MR 15 mg/l 30 mg/l 0.0125 mg/i 0.645 mg/I MR.- 0.019 mg/I MR 20 mg/I 100 mg/I 0.0125 mg/I 0.645 mg/I 0.077 mg/I 4.3

mg/I Measurement Frequency 1/week

.1/c 1/month l/month 1/month I/D I/D 1E I/E Sample Type InstantaneousA Grab Grab Grab Grab Grab Grab Grab Grab ASee Part .II, Special Condition #14 BSee Part II, Special Condition #15 CAfter ireatmeit with hypochlorite has occurred in a WC pond, sampling for TRC shall be conducted once per day over a two day period during discharge from the WC pond. DSampling shall be conducted once per chemical metal cleaning occurrence of discharge of these substances through Outfall 002 but need not be more than twice per month. ESampling shall be conducted once per occurrence of discharge of these substances through Outfall 002 but need not be more than twice per month. Based on an average flow of 1.41 MGD I MR = Monitor and Report 'IO 'IC 'I a o 00

a. The pH shall not be less than 6.0 standard units nor greater than 9.0 standard units and shall be monitored and reported once per week by grab sample.

b. There shall be no discharge of floating solids or visible foam in other than trace amounts; nor, shall the effluent cause a visible sheen on the receiving waters.

c. Samples taken in compliance with the monitoring requirements specified above shall be taken at the following location(s):

at the point of discharge from the conventional waste treatment (WC) system but prior to mixing with the receiving waters. a

A. EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS

3. During the period beginning on the effective date of this permit and lasting through the expiration date, the permittee is authorized to discharge from outfall(s) serial number(s) 003: treated sanitary sewerage to Lake Wylie.

Such discharge shall be limited and monitored by the Permittee as specified below: EFFLUENT CHARACTERISTICS (lbs/d -Monthly Average DISCHARGE LIMITATIONS ay) Other Units (Specify) Daily Monthly Daily Maximum Average Maximum MONITORING REQUIREMENTS .I Measurement Sample Frequency Type Flow (MGD) Total Residual Chlorine (TRC).' Total Suspended Solids Carbonaceous Biochemical Oxygen Demand (5-day) Fecal Coliform Dissolved Oxygen Phosphorous, total ... I

1. I

- MR 0.5 mg/I 90 mg/l MR 1.0 mg/I 135 mg/I 1/month I/week' 1/month I!month 1/month 1/month 1/month InstantaneousA Grab 24Hr. Composite 24Hr. Composite Grab Grab Grab 25 mg/I 50 mg/I-200/100 ml 400/lOOml at a minimum of 1.0 mg/l MR MR. ASee Part III, Special Condition #14 'Sampling for total residual chlorine shall be conducted once per week when chlorine is used i sIt e f in the sanitary treatment facility. MR = Monitor and Report Based on an average flow of 0.028 MGD I I

a. The pH shall not be less than 6.0 standard units nor greater than 9.0 standard units and shall be monitored and reported once per week by grab sample:.

b. There shall be no discharge of floating solids or visible foam in other than trace amounts; nor, shall the 'effluent cause a visible sheen on the receiving waters.

c. Samples taken in compliance with the monitoring requirements specified above shall be taken at the following location(s):

at the point of discharge from the sewage treatment plant prior to mixing with the receiving waters. 8 CD o' 0 00

I EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS,

4. During the period beginning on the effective date of this permit and lasting through the expiration date, the permittee is authorized to discharge from outfall(s) serial number(s) 004: liquid radiological wastes via Outfall 001 to Lake Wylie; Such discharge shall be limited and monitored by the Permittee as specified below:

EFFLUETCA .RT ..EISIC EFFLUENT CHARACTERISTICS Month] Averap DISCHARGE LIMITATIONS (lbs/day) Other Units (Specify) ly Daily Monthly -- Dai ,e Maximum Average Ma MR MONITORING REQUIREMENTS ly Ximum MR

• Measurement Frequency 1/occurrenceB Sample Type EstimateA Flow (MGD). ;.

Copper, total. Iron,. total 1.0 mg/l 1.0 mg/l 1.0 mg/I 1.0 mg/I 1/occurrenceB I/occurrenceB Grab Grab Based on an average flow of 0.009 MGD MR = Monitor and Report .. i. ASee Part III, Special Condition #14 Saxnpling shall be conducted once per occurrence of chemical metal cleaning through Outfall 004.

a. Samples taken in compliance with the monitoring requirements specified above shall be taken at the following location(s):

at the point of discharge from the liquid radiological waste treatment plant but prior to mixing with other wastewaters at Outfall 001.- 'O It CD0 9-C 00 IV This discharge is regulated by the Nuclear-Regulatory Commission (NRC) and is monitored per their specifications and the results are reported to NRC.

k.

EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS

5. During the period beginning on the effective date of this permit and lasting through the expiration date, the permittee is authorized to discharge from outfall(s) serial number(s) 005: cooling tower blowdown via Outfall 001 to Uke Wylie.

Such discharge shall be limited and monitored by the Permittee as specified below: EFFLUENT CHARACTERISTICS DISCHARGE LIMITATIONS MONITORING REQUIREMENTS (lbs/day) Other Units (Specify), Monthly

Daily, Monthly Daily Measurement Sample Average Maximum Average Maximum Frequency Type Flow (MGD)

MR-MR Weekly Estimate Free Available Chlorine (FAC) 0.2 mg/I 0.5 mg/l 1/week Multiple GrabsB ASee Part III, Special Condition #14. 'See Part'III, Special Condition #17 MR Monitor and Report No chromium and zinc based maintenance chenmicals will be allowed in the cooling tower.

a. The Permittee shall annually, through monitoring or engineering calculations, certify that the other 124 -priority pollutants' (besides chromium and zinc) are present at no detectable amount in the cooling tower blowdown discharge as.a result of the a

H addition of cooling tower maintenance chemicals. ZaC

b. The pH shall not be less than 6.0 standard units nor greater than 9.0 standard units and shall be monitored and reported once per week by grab sample.-

c. Samples taken in compliance with the monitoring requirements specified above shall be taken at the following location(s):

0 at the point of discharge from the cooling towers prior to mixing with wastewaters at Outfall 001.

A. EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS

6.

During the period beginning on the effective date of this permit and lasting through the expiration date, the permittee is authorized to discharge from outfall(s) serial number(s) 006: once through non-contact cooling water to the Standby Nuclear Service Water Pond to Lake Wylie. Such discharge shall be limited and monitored by the permittee as specified below: EFFLUENT CHARACTERISTICS DISCHARGE LIMITATIONS MONITORING REQUIREMENTS kg/day (lbs/day) Other Units (Specify) Monthly Daily Monthly Daily Measurement Sample Average Maximum Average Maximum FrequencyA ype Flow (MGD) MR MR 1/occurrence EstimateC Intake Temperature OC(OF) MR MR 1/occurrence Grab Discharge Temperature IC(OF). MR MR 1/occurrence Grab Temperature RiseOC(°F)D MR 1/occurrence Calculation Total Residual Chlorine (TRC)BE 0.011 mg/l 0.019 mg!l 1/occurrence Multiple GrabsF ASince Outfall 006 is only used intermittently, the samples shall be taken during the period when the Standby Nuclear Service Water Pond is being used, but need not be more than once per week. BMonitoring for total-residual chlorine shall be required when chlorine is being used. CSee Part III, Special Condition #14 DSee Part III, Special Condition #24 ESee Part III, Special Condition #15 & 16 MR = Monitor and Report Results FSee Part III, Special Condition #17 Based on a flow of 27.4 MGD X Q

a.

The pH shall not be less than 6.0 standard units nor greater than 9.0 standard units and shall be monitored by grab sample z _, A 0 at a frequency of once per occurrences..

b.

There shall be no discharge of floating solids or visible foam in other than trace amounts; nor, shall the effluent cause a visible sheen on the receiving waters.i - 00

c.

Samples taken in compliance with the monitoring requirements specified above shall be taken at the following location(s): The intake temperature shall be monitored at or near the plant intake. All'other parameters shall be monitored at or near the point of discharge from Outfall 006 prior to mixing with the receiving waters, unless otherwise specified above.

PART I Page 8 of 27 Permit No. SC0004278 B. EFFLUENT TOXICITY LIMITATIONS AND MONITORING REQUIREMENTS

1. During the period beginning on the effective date of this Permit and lasting through the expiration date, the permittee is authorized to discharge from outfall(s) serial number(s).001i-once through cooling water, nuclear service water, cooling tower blowdown.(discharged via internal Outfall 005) and liquid radiological wastes (treated and discharged via internal Outfall 004) to Lake Wylie.

Such discharge shall be limited and monitored by the permittee as specified below: k DISCHARGE EFhLUENT LIMITATIONS MIONITORING REQUIREMENTS CHARACTERISTICS Monthly Daily Measurement Sample

Average, Maximum

... Frequency Type Whole Effluent Toxicity Chronic Testing @ 24 hour composite CTC=100% 01 lIquarter. 'Report 10" if test passes or "I" if test fails in accordance with Part III.A.13 a, b, c

a. Samples taken in compliance with the monitoring requirements.specified above shall be taken at the following location(s): at the point of discharge from Outfall 001 prior to mixing with the'receiving waters, unless otherwise specified above.

il I PART I Page 9 of 27 Permit No. SC0004278 B. EFFLUENT TOXICITY LIMITATIONS AND MONITORING REQUIREMENTS

2. During the period beginning on the effective date of this permit and lasting through the expiration date, the permittee is authorized to discharge from outfall(s) serial number(s) 002: low volume wastes, miscellaneous dilute wastewater, and metal cleaning wastes to Lake Wylie.

Such discharge shall be limited and monitored by the permittee as specified below: DISCHARGE EFFLUENT LIMITATIONS MONITORING REQUIREMENTS CHARACTERISTICS Monthly

Daily Measurement Sample

-Average Maximum Frequency Type Whole Effluent Toxicity Chronic Testing @ 24 hour composite CTC=100% 01 I/quarter 'Report '0" if test passes or *1" if test fails in accordance with Part III.A.13 a, b, c

a. Due to the intermittent and variable duration of the batch discharges for Outfall 002, the sampling protocol for chronic testing is modified to allow Duke Power Company to conduct the chronic testing with only one or two samples in instances when flow is not available.

b.Samples taken in compliance with the monitoring requirements specified above shall be taken at the following location(s): at the point of discharge from the conventional waste treatment (WC) system but prior to mixing with the receiving waters.

PART I Page 10 of 27 Permit No. SC0004278 C. GROUNDWATER MONITORING REQUIREMENTS

1. During the period beginning on the effective date of this permit and lasting through the expiration date, each of the four (4) groundwater monitor wells shall be sampled by the permittee as specified below:

PARAMETER LIMITATION: MEASUREMENT FREQUENCY Water Table Elevation, MSL, tenth/feet Total Dissolved Solids, mg/I Total Organic Carbon, mg/l pH (field), standard units Specific Conductance (field), umhos/cm Ammonia, (NH3) mg/I Nitrate, (NO3), mg/I Sulfate, mg/I Arsenic, total, mg/l Barium, total, mg/l Cadmium, total, mg/l Chromium, total, mg/l Copper, total, mg/I Iron, total, mg/l Lead, total, mg/I Manganese, total, mg/l Mercury, total, mg/i Selenium, total, mg/l Silver, total, mg/l Zinc, total, mg/l MR

• MR MR MR
• . MR MR MR MR MR
• MR MR MR MR MR MR

. MR. . MR MR .MR. - MR Semiannually Semiannually Semiannually .Semiannually Semiannually Semiannually Semiannually Semiannually Semiannually Semiannually Semiannually Semiannually Semiannually Semiannually .Semiannually Semiannually Semiannually Semiannually. Semiannually' Semiannually I.. MR = Monitor and Report

2. Sample collection methods shall be in accordance with EPA - Standard Operating Procedures, Quality Assurance Manual 1991, or the most recent revision.

3. All groundwater monitoring wells must be properly maintained at all times.

4. All groundwater monitoring is a SCDHEC requirement.

I,. PART I Page 11 of 27 Permit No. SC0004278 D. SCHEDULE OF COMPLIANCE

1. The permittee shall achieve compliance with the effluent limitations specified for discharges in accordance with the following schedules:

Not Applicable

2. No later than 14 calendar days following a date identified in the above schedule of compliance, the permittee shall submit either a report of progress or, in the case of specific actions being required by identified dates; a written notice of compliance or noncompliance. In the latter case, the notice shall include the cause of noncompliance, any remedial actions taken, and the probability of meeting the next scheduled requirement.

PART I Page 12 of 27 Permit No. SC0004278 E. MONITORING AND REPORTING

1. Representative Sampling Samples and measurements taken as required herein shall be representative of the volume and nature of the monitored discharge.

2. Flow. Measurements Appropriate flow measurement devices and methods consistent with accepted scientific practices shall be present and used to ensure the accuracy and reliability of measurements of the volume of monitored discharges. The devices shall be installed, calibrated and maintained to ensure that the accuracy of the measurements are consistent with the accepted capability of that type of device. Devices selected shall be capable of measuring flows with a maximum deviation of less than + 10% from the true discharge rates throughout the range of expected discharge volumes. The primary flow device must be accessible to the use of a continuous flow recorder.

Where a flume is present, a separate stilling well for Department/EPA use must be provided if required by the Department.

3. Reporting Monitoring Results

a.

Effluent Monitoring Monitoring results obtained each month shall be reported monthly on a Discharge Monitoring Report Form (EPA Form 3320-1). The first report is due postmarked no later than the 28th day of the month following the month this permit becomes effective.

b.

Groundwater Monitoring Groundwater monitoring results shall be submitted semiannually.on a Groundwater Monitoring Form (DHEC 2110), and postmarked no later than the 28th of the fiionth foliowing the completed reporting period. Each of the semiannually groundwater monitoring reports are due on the 28th of the months of July, and January. Please reference Site ID #00534.

c.

Submittal of Reports ,One original and one copy of these, and all other reports required herein, shall be submitted to: SC Department of Health and Environmental Control (SCDHEC) ATTN: Bureau of llWater/Water'Pollution Enforcement Section 2600 Bull Street Columbia, South Carolina 29201 A copyof the Groundwater Monitoring Report shall be submitted to:.- -SC Department of Health and Environmental Control (SCDHEC) ATTN: Bureau of Water/Groun'dwater Quality Section 2600 Bull Street Columbia, South Carolina 29201

I PART I Page 13 of 27 Permit No. SC0004278

4. Test Procedures Test procedures for the analysis of pollutants shall conform to regulations published pursuant to State Environmental Laboratory Certification Regulation 61-81 and Section 304(h) of the Act, as amended.

(Federal Register, October 16, 1973; Title 40, Chapter 1, Sub-chapter D, Part 136 "Guidelines Establishing Test Procedures for the Analysis of Pollutants." Amended by Federal Register, December 1, t976, and any other amendments that may be promulgated).

5. Recording of Results For each measurement or sample taken pursuant to the requirements of this permit, the permittee shall record the following information:

a.

the exact place, date and time of sampling;

b.

the dates and times the analyses were performed;

c.

the person(s) who performed the analyses and the laboratory certification number where applicable;

d.

the analytical techniques or methods used; and

e.

the results of all required analyses.

6. Additional Monitoring by Pernittee If the permittee monitors any pollutant at the lecation(s) designated herein more frequently than required by this permit, using approved analytical methods as specified herein, the results of such monitoring shall be included in the calculation and reporting of the values required in the Discharge Monitoring Report Form (EPA-3320-1). Such increased frequency shall also be indicated. Additional or accelerated monitoring may be required to determine the nature and impact of a non-complying discharge on the environment or to determine if a single non-complying sample is representative of the long term condition (monthly average).

7. Records Retention All records and information resulting from the monitoring activities required by this permit including all records of analysis performed and calibration and maintenance of instrumentation and recordings from continuous monitoring instrumentation shall be retained for a minimum of three (3) years, or longer if requested by the Department. The permittee shall furnish to the Department, upon request, copies of records required to be kept by this permit.

PART I Page 14 of 27 Permit No. SC0004278

8. Definitions

a.

- The "monthly'average", other than for fecal coliform, is the arithmetic mean of all samples collected in a calendar month period.- The monthly average for fecal coliform bacteria is the geometric mean of all samples collected in a calendar month period, The monthly average loading is the arithmetic average of all individual loading determinations made during the month.

b.

The "weekly average',, other than for fecal coliform, is the arithmetic mean of all the samples . :collected during a one-week period. For self-monitoring purposes, weekly periods in a calendar month are defined as three consecutive seven day intervals starting with the first day of the calendar month and a fourth interval containing seven days plus those days beyond the 28th day in a calendar month. The value to be reported is the single highest of the four weekly averages computed during a calendar month. The weekly average loading is the arithmetic average of all individual loading determinations made during the week.;

c.

The "daily maximum" is the highest average value recorded of samples collected on any single day of the calendar month.

d.

The "instantaneous maximum or minimum" is the highest or lowest value recorded of any sample collected during the calendar month.

e.

Arithmetic Mean: The arithmetic mean of any set of values is the summation of the individual values divided by the number of individual values.

f.

Geometric Mean: The geometric mean of any -set of values is the Nth -root of the product of the individual values where N is equal to the number of individual values. The geometric mean is equivalent to the antilog of the arithmetic mean of the logarithms of the individual values. For ' purposes of calculating the geometric mean, values of zero.(0) shall be considered to be one (1).

g.

Department: The South Carolina Department of Health and Environmental Control.

h.

Act:' The'Clean Water Act (Formerly referred to as the Federal Water Pollution Control Act) Public'Law 92-500, as amended.

i.

Grab Sample: An individual discrete or single influent or effluent portion of at least 100 milliliters collected at a time representative of the discharge and over a period not exceeding 15 minutes and retained separately for analysis. Instantaneous flow measured at the time of grab sample collection shall be used to calculate quantity.

j.

Composite Sample: One of the following four types of composite samples as defined is specified within this permit:

I1 I PART I Page 15 of 27 Permit No. SC0004278 (1) An influent or effluent portion collected continuously over a specified period of time at a rate proportional to the flow. (2) A combination of not less than eight (8) influent or effluent grab samples collected at regular (equal) intervals over a specified period of time, properly preserved, (See Part I.D.4.) and composited by increasing the volume of each aliquot in proportion to flow. If continuous flow measurement is not used to composite in proportion to flow, the following method will be used: Take an instantaneous flow measurement each time a grab sample is collected. At the end of the sampling period, sum the instantaneous flow measurements to obtain a total flow to determine the partial amount (percentage) of each grab sample to be combined to obtain the composite sample. (3) A combination of not less than eight (8) influent or effluent grab samples of equal volume but at variable time intervals that are inversely proportional to the volume of the flow. That is, the time interval between aliquots is reduced as the volume of flow increases. (4) A combination of not less than eight (8) influent or effluent grab samples of constant (equal) volume collected at regular (equal) time intervals over a specified period of time, while being properly preserved. Continuous flow or the sum of instantaneous flows measured and averaged for the specified compositing time period shall be used with composite sample results to calculate quantity.

9. Right of Entry The permittee shall allow the Commissioner of the Department of Health and Environmental Control, the Regional Administrator of EPA, and/or their authorized representatives:

a.

To enter upon the permittee's premises where a regulated facility or activity and effluent source is located in which any records are required to be kept under the terms and conditions of this permit,

and,

b.

At reasonable times to have access to and copy any records required to be kept under the terms and conditions of this permit; to inspect any facilities, equipment (including monitoring and control equipment), practices or operations regulated or required under this permit and sample or monitor any substances or parameters at any location for the purposes of assuring permit compliance.

PART I Page 16 of 27 Permit No. SC0004278 A. GENERAL REQUIREMENTS

1. Duty to Comply The permittee must comply with all condition's of this permit. Any permit noii-compliance constitutes a violation of the Act and the S.C. Pollution Control Act and is grounds for enforcement action; for permit termination, revocation and reissuance, or 'modification; or for the denial 'of a' permit renewal application.

2. Civyl and Criminal Liability

a. 'Any person who violates a term, condition or scliedule of compliaince contained within this permit A'is subject to the actions defined by Sections 48-1-320 and 48-1-330 of the SC Pollution Control Act.

b.

Except as provided in permit conditions on "Bypassing" (Part Il.C.2.), nothinig in this permit shall be construed to relieve the permittee from civil or criminal penalties for non-compliance.

c.

It shall not be an acceptable defense of the permittee in an enforcement action that it w'ould have been necessary to halt or reduce the permitted activity in order to maintain co'mpliance with the conditions of this permit.

d.

It is the responsibility of the permittee to have a treatment facility that will meet the final effluent 'limitations of this permit. The 'approval of plans and specifications by the Department does not relieve the permittee of responsibility for compliance.

3. Oil and Hazardous Substance Liability Nothing in this permit shall be construed to preclude the institution of any le"gal action or relieve the permittee from any respon'sibilities, liabilities,C6r penalties to which the pefmittee is or may be subject to under Section 311 of the Act, 'the S.C. Pollution Control Act'or applicable provisions of the S.C.

Hazardous Waste Management Act and the'S.C. Oil and 'Gas Act.

4. Permit Modification

a.

The permittee shall furnish-to the Department within a reasonable time any relevant information which the Department may request to determine whether cause exists for modifying, revoking and reissuing, or terminating the permit, or to determine compliance with the permit.

b.

Upon sufficient cause, this permit may be modified, revoked, reissued,'or terminated during its term, after public notice and opportunity for a hearing. Modifications deemed to be minor will not require public notice.

c.

'The filing of a request by the permittee for a permit modification, or a notification of planned changes or anticipated non-compliance, does not stay any permit condition.

- IL~ I IL-PART I Page 17 of 27 Permit No. SC0004278

5. Toxic Pollutants Notwithstanding Part II.A.4. above, if a toxic effluent standard or prohibition (including any schedule of compliance specified in such effluent standard or prohibition) is established under Section 307(a) of the Act for a toxic pollutant which is present in the discharge and such standard or prohibition is more stringent than any limitations for such pollutant in this permit, this permit shall be revised or modified in accordance with the toxic effluent standard or prohibition and permittee so notified.

6. State Laws Nothing in this permit shall be construed to preclude the institution of any legal action or relieve the permittee from any responsibilities, liabilities, or penalties established pursuant to any applicable State law'or regulation under authority preserved by Section 510 of the Act.

7. Property Rights The issuance of this permit does not convey arny property rights in either real or personal property, or any exclusive privileges, nor does it authorize any injury to private property or any invasion of personal rights, nor any infringement of Federal, State, or local laws or regulations.

8. Severability The provisions of this permit are severable, and if any provisions of this permit, or the application of any provision of this permit to any circumstances, is held invalid, the application of such provision to other circumstances, and the remainder of this permit shall not be affected thereby.

9. Onshore and Offshore Construction This permit does not authorize or approve the construction of any onshore or offshore physical structures or facilities or the undertaking of any work in any navigable waters.

PART II Page 18 of 27 Permit No. SC0004278 B. REPORTING REQUIREMENTS

1. Change in Discharge All discharges authorized herein shall be consistent with the terms and conditions of this permit. The discharge of any pollutant identified in this permit more frequently than or at a level in excess of that authorized shall constitute a violation of the permit. Any planned facility expansions, production increases, or process modifications which will result in a new or different discharge of pollutants must be reported by submission of a new NPDES application or, if such changes will not violate the effluent limitations specified in this permit, by notice to the Department of such changes. Following'such notice, the permit may be modified to specify and limit any pollutant not previously limited.

2. Twenty-Four Hour Non-Compliance Reporting

a.

The permittee shall report any non-compliance with provisions specified in this permit which may endanger public health or the environment. The permittee shall notify the Department orally within 24 hours of becoming aware of such conditions. During normal working hours call 803/8984300. After hour reporting should be. made to the 24 hour Emergency Response -.:telephone number.803/253-6488. The permittee shall provide the following information to the Department in writing, within five (5) days of becoming aware of such conditions:

1.

A description of the discharge and cause of non-compliance; and,

2.

The period of non-compliance, including exact dates and times; or, if not corrected, the anticipated time the non-compliance is expected -to continue, and steps being taken to reduce, eliminate and prevent recurrence of the non-complying discharge.

b.

The following violations shall be included in a 24 hour report when they might endanger health or the environment:

1.

An unanticipated bypass which exceeds any.effluent limitation in this permit;

2.

Any upset which exceeds any effluent limitation in the permit.

c.

As soon as the permittee has knowledge of or anticipates the need for a bypass, but not later than 10 days before the date of the bypass, it shall notify the Department and provide a determination of the need for bypass as well as the anticipated quality, quantity, time of duration, and effect of the bypass.

3. Other Non-Compliance The permittee shall report in narrative form, all instances of non-compliance not previously reported under Section B, Paragraph B.2., at the time Discharge Monitoring Reports are submitted. The reports shall~contain the information listed in Paragraph B.2.a.-

I I

tL I ~n PART II Page 19 of 27 Permit No. SC0004278

4. Transfer of Ownership or Control A permit may be transferred to another party under the following conditions:

a.

The permittee notifies the Department of the proposed transfer at least thirty (30) days in advance of the proposed transfer date;

b.

A written agreement is submitted to the Department between the existing and new permittee containing a specific date for the transfer of permit responsibility, coverage, and liability for violations up to that date and thereafter. Transfers are not effective if, within thirty (30) days of receipt of proposal, the Department disagrees and notifies the current permittee and the new permittee of the intent to modify, revoke and reissue, or terminate the permit and to require that a new application be filed.

5. Expiration of Permit The permittee is not authorized to discharge after the expiration date of this permit, unless a completed application for reissuance is submitted no later than 180 days prior to the expiration date. Permission may be granted to submit an application later than this, but not later than the expiration date of the permit. In accordance with Section 1-23-370 of the code of laws of South Carolina, if a timely and sufficient application is made for any activity of a continuing nature, the existing permit does not expire until a final determination is made to renew or deny renewal of the existing permit.

6. Signatory Requirements All applications, reports or information submitted to the Department shall be signed and certified.

a.

All permit applications shall be signed as follows:

1.

For a corporation: by a principal executive officer of at least the level of vice-president or by a duly authorized representative;

2.

For a partnership or sole proprietorship: by a general partner or proprietor, respectively; or,

3.

For a municipality, State, Federal or other public agency: by either a principal executive officer or ranking elected official.

b.

All reports required by the permit and other information requested by the Department shall be signed by a person described above or by duly authorized representative only if:

1.

The authorization is made in writing by a person described above and submitted to the Department;

PART II Page 20 of 27 Permit No. SC0004278

2.

The authorization specifies either an individual or a position having responsibility for the overall operation of the regulated facility or activity, such as the position of plant manager, superintendent, or position of equivalent responsibility. (A duly authorized representative may thus be either a named individual or any individual occupying a named position.)

7. Availability of Reports Except for data determined to be confidential under Section 48-1-270 of the S.C. Pollution Control Act, all reports prepared in accordance with the terms and conditions of this permit shall be available for public inspection at the offices of the Department and the -Regional Administrator..As required by the Act effluent data shall not be considered confidential. Knowingly making any false statement on any such report may result in the imposition of criminal penalties as provided for in Section 48-1-340 of thee S.C, Pollution Control Act.

8. Changes in Discharges of Toxic Pollutants'or Hazardous Substances

a.

The permittee shall notify the Department as soon as it knows or has reason to believe that any activity has occurred or will occur which would result in the discharge in any outfall of:

• 1.

Any toxic pollutant(s) identified under Section 307(a) of the Act which exceed the highest of the following concentrations and are not limited in the permit. 1 mg/I for antimony (Sb): 0.500 mg/l for 2,4-dinitrophenol or 2-methyl-4,6-dinitrophenol; 0.200 mg/i for acrolein or acrylonitrile; 0.100 mg/i for any other toxic pollutant; or, Ten (10) times the maximum concentration value reported in the permit application.. '

2.

Any hazardous substance(s) identified under Section 311 of the Act as determined by Federal Regulation 40 CFR 117.

b.

The permittee must notify the Department as soon as it knows or has reason to believe that it has begun or expects to begin to use or-manufacture as an intermediate or final product or by-product any toxic pollutant or hazardous substance which was not reported in the permit application.

T I U __

LL_ PART II Page 21 of 27 Permit No. SC0004278 C. OPERATION AND MAINTENANCE

1. Facilities Operation

a.

The permittee shall at all times properly operate and maintain all facilities and systems of treatment and control (and related appurtenances) which are installed or used by the permittee to achieve compliance with the conditions of this permit. Proper operation and maintenance includes effective performance based on design facility removals, adequate funding, adequate operator staffing and training, and adequate laboratory and process controls as determined by the laboratory certification program of the Department. This provision requires the operation of back-up or auxiliary facilities or similar systems only when necessary to achieve compliance with the conditions of the permit. Maintenance of facilities, which necessitates unavoidable interruption of operation and degradation of effluent quality shall be scheduled during non-critical water quality periods and carried out in a manner approved by the Department.

b.

The permittee shall provide for an operator, as certified by the South Carolina Board of Certification for Environmental Systems Operators, with a grade equal to or higher than the classification designated in Part III.A.3. The name and grade of the operator of record shall be submitted to the Department prior to placing the facility into operation. A roster of operators associated with the facility's operation and their certification grades shall also be submitted with the name of the "operator-in-charge". Any changes in operator or operators shall be submitted to the Department as they occur.

2. Bypassing Any intentional diversion from or bypass of waste streams from any portion of wastewater collection and treatment facilities which is not a designed or established operating mode for the facility is prohibited except (a) where unavoidable to prevent loss of life, personal injury or severe property damage, or (b) where excessive storm drainage or run-off would damage any facilities necessary for compliance with the effluent limitations and prohibitions of this permit and there were no feasible alternatives to the bypass, such as the use of auxiliary treatment facilities or retention of untreated wastes. "Severe property damage" does not mean economic loss caused by delays in production.

3. Duty to Mitigate, Halt or Reduce Activity The permittee shall take all reasonable steps to prevent, minimize or correct any adverse impact on public health or the environment, resulting from non-compliance with this permit. Upon reduction, loss, or failure of the treatment facility, the permittee shall, to the extent necessary to maintain compliance with this permit, control production or all discharges or both until the facility is restored or an alternative method of treatment is provided.

PART II Page 22 of 27 Permit No. SC0004278

4. Power Failures In order to maintain compliance with effluent limitations and prohibitions of this permit, the permittee shall either:

a.

In accordance with the Schedule of Compliance contained in Part I.D., provide an:alternative power source sufficient to operate the wastewater control facilities; or, if such' alternative power source is not in existence, and no date for its implementation appears in Part I.D., have a plan of operation which will:

b.

Halt, reduce, or otherwise control production and/or all discharges upon the reduction, loss, or failure of the primary source of power to the wastewater control facilities.

5. Removed Substances Solids, sludges, filter backwash or other residuals removed in the course of treatment or control of wastewaters shall be disposed of in a manner. such as t6 prevent such'materials from entering State waters and in accordance with guidelines issued 'pursuant to Secti6n 405 of the 'Act, and the 'terms of a construction or NPDES and/or solid or hazardous waste permit issued by the Department.

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11 .
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U_ PART III Page 23 of 27 Permit No. SC0004278 PART III A. OTHER REQUIREMENTS

1. The Permittee shall maintain at the permitted facility a complete Operations and Maintenance (O & M)

Manual for the waste treatment plant. The manual shall be made available for on-site review during normal working hours. The manual shall contain operation and maintenance instructions for all equipment and appurtenances associated with the waste treatment plant. The manual shall contain a general description of the treatment process(es), operating characteristics that will produce maximum treatment efficiency, and corrective action to be taken should operating difficulties be encountered.

2. The Permittee shall provide for the perfcrnmance of routine daily treatment plant inspections. These inspections are the responsibility of a certified operator of the appropriate grade as defined in Part II.C. 1. The inspection shall include, but is not limited to, areas which require a visual observation to determine efficient operations and for which immediate corrective measures can be taken using the 0 &

M manual as a guide. All inspections shall be recorded and shall include the date, time and name of the person making the inspection, corrective measures taken, and routine equipment maintenance, repair, or replacement performed. The Permittee shall maintain all records of inspections at the permitted facility as required by Part I.D.7., and the records shall be made available for on-site review during normal working hours.

3. The wastewater treatment plant has been assigned a classification of Group 1I-B in the Permits to Construct which are issued by the Department. This classification corresponds to an operator with a Grade of C-B or higher.

4. The Permittee shall maintain an all weather access road to the wastewater treatment plant and appurtenances at all times.

5. The Permittee shall continue to maintain a Best Management Practices (BMP) plan to identify and control the discharge of significant amounts of oils and the hazardous and toxic substances listed in 40 CFR Part 117 and Tables II and III of Appendix D to 40 CFR Part 122. The plan shall include a listing of all potential sources of spills or leaks of these materials, a method for containment, a description of training, inspection and security procedures, and emergency response measures to be taken in the event of a discharge to surface waters or plans and/or procedures which constitute an equivalent BMP. Sources of such discharges may include materials storage areas; in-plant transfer, process and material handling areas; loading and unloading operations; plant site runoff; and sludge and waste disposal areas. The BMP plan shall be developed in accordance with good engineering practices, shall be documented in narrative form, and shall include any necessary plot plans, drawings, or maps. The BMP plan shall be maintained at the plant site and shall be available for inspection by EPA and Department personnel.

6. There shall be no discharge of polychlorinated biphenyl compounds such as those commonly used for transformer fluid.

PART III Page: 24 of 27 - Permit No. SC0004278

7. The permittee shall monitor all parameters consistent with conditions established by this permit on the 1st Tuesday of every calendar month; unless'otherwise appioved by this'Department.

Should the 1st Tuesday fall on a holiday, monitoring may be conducted on the following work day. Additional monitoring, as necessary to meet the frequency requirements of this permit (Part I.A. Effluent Limitations and Monitoring Requirements) shall be'performed by the permittee. Toxicity monitoring shall be conducted at the frequency lstafed in Part I.B. -Effluent Toxicity Limitations and Monitoring Requirements. The permittee shall notify the Department two (2) weeks prior to any changes in the monitoring schedule.;

8. Unless authorized elsewhere in this permit, the permittee shall meet the following requirements concerning maintenance chemicals for the following waste streams: once-through non-contact cooling water, and cooling tower blowdown. Maintenance chemicals shall be defined as any man-induced additives to the above-referenced waste streams. This includes materials added for corrosion inhibition including zinc chromium, and phosphorus.

r t

a.

The discharge, in detectable amounts, of any of the one hundred and twenty-six priority pollutants is prohibited, if the pollutants are present due to the use of maintenance chemicals.

b.

Slimicides, algicides' and biocides' shall be used in accordance with registration requirements of the Federal Insecticide, Fungicide and Rodenticide Act.' c The use of maintenance chemicals containing bis(tributyltin) oxide is prohibited unless written approval is obtained from SCDHEC.

d.

Any maintenance chemicals added to the above referenced -waste streams must degrade rapidly, either'due to hydrolytic decomyosition or biodegradation. -~I' i

e.

The discharge of maintenance 'chemicals added to waste streams must be limited to concentrations which protect indigenous aquatic populations in the receiving stream and shall not exceed the "no observed effect level (NOEL)". The permittee shall keep sufficient documentation on-site which support that the above requirements are being met. The information -shall -be made available for on-site review by Department personnel during normal working hours. The occurrence of in-stream problems may necessitate'the submittal of 'chemical additive data and may require a permit' modification to include additional monitoring and limitations; The permittee may demonstrate compliance with these limitations to the South Carolina Department of Health and Environmental Control by either sampling and analyzing for the' pollutants in the discharge or providing mass balance calculations to demonstrate that use of particular maintenance chemicals will not result in detectable amounts of the toxic pollutants in the discharge.

I 1 PART III Page 25 of 27 Permit No. SC0004278

9. The company shall notify the South Carolina Department of Health and Environmental Control in writing no later than sixty (60) days prior to instituting use of any additional maintenance chemicals in the systems identified in Part 1II.A.8. Such notification shall include:

- Name and general composition of the maintenance chemical - Quantities to be used - Frequency of use - Proposed discharge concentration - EPA registration number, if applicable - Aquatic toxicity information A. 10.,' All sludges, waste oil and solid and hazardous waste shall be properly disposed of in accordance with the rules and regulations of the SC DHEC Bureau of Land and Waste Management.

11. The South Carolina Department of Health and Environmental Control has determined that pursuant to Section 316(a) of the Act that the thermal component of the discharge controlled by the temperature criteria on page 2 of this permit assures the protection and propagation of a balanced, indigenous population of fish, shellfish, and wildlife.

12. Neither free available chlorine nor total residual chlorine may be discharged from any unit for more than two hours in any one day, and not more than one unit in any plant may discharge free available or total residual chlorine at any one time unless the permittee can demonstrate to SC DHEC that the units in a particular location cannot operate at or below this level of oxidation.

13. (a)

A three-brood chronic toxicity test shall be conducted at the frequency stated in Part l.B.Effluent Toxicity Limitations and Monitoring Requirements using a control and the chronic test concentration (CTC) of 100% effluent. The test shall be conducted using EPA Method 1002.0, which uses Ceriodaphnia dubia as the test organism, in accordance with "Short-Term Methods for Estimating Chronic Toxicity of Effluents and Receiving Waters to Freshwater Organisms," (EPA/600/4-911002; 3r' ed.). (b) If the test group Ceriodaphnia dubia survival and/or reproduction is less than the control group survival and/or reproduction by a percent significant at the 0.01a level (99 percent one-ended confidence level), the test shall be deemed a failure. (c) The permittee must report on the discharge monitoring report (DMR) form whether the test passes or fails at the specified CTC. If the test fails, the number " 1 " shall be placed on the form. If the test passes, the number "0" shall be placed on the form. The DMR Attachment for Toxicity Test Results shall also be completed and submitted with the DMR.

14. The permittee shall maintain at the permitted facility a record of the method(s) used in measuring the discharge flow:

PART III Page 26 of 27 Permit No. SC0004278 a) Estimate b) c) Instantaneous Continuous - Pump Curve, Production Chart, Water Use Records, Valve Opening, Tank Volume - Bucket and Watch, Weir and Gauge, Parshall Flume - Totalizer, Continuous Chart Recorder Records of any necessary calibrations must also be kept. This information shall be made available for on-site review by Department personnel during normal working hours.

15. The Water Quality-Based Effluent Limitations (WQBEL) for the parameters listed are not quantifiable using EPA-approved analytical methods. Therefore, the Department has set a

-'.. reporting threshold to measure the acceptable quantification level for these parameters. This reporting threshold does not authorize the discharge of any pollutant in excess of the WQBEL. I,

a.

For purposes of reporting, the Permittee shall use the reporting threshold equivalent to the Minimum Level.. The Minimum Level is defined as the concentration in a sample equivalent to the concentration of the lowest calibration standard analyzed in a specific analytical procedure assuming that all the method-specified sample weights, volumes, and processing steps have been followed. As such, the Permittee must conduct analyses in accordance with the method specified below and must utilize a standard equivalent to the

1. concentration of the Minimum Level specified below:

Parameter Minimum Level Total Residual Chlorine (TRC); 0.05 mg/I

b.

For the purposes of reporting on the Discharge Monitoring Report (DMR), actual analytical results should be reported whenever possible. All analytical results should be reported whenever possible. All analytical values at or above the Minimum Level shall be reported as the measured value. When results cannot be quantified, values below the Minimum Level shall be reported as "0".

16. Free Available Chlorine (FAC) and Total Residual Chlorine (TRC) procedures will be used to detect any oxidants present, such as sodium bromide and sodium hypochlorite, rather than establishing limitations for Free Available Oxidant (FAO) and Total Residual Oxidant.

17. Multiple grabs shall consist of grab samples.collected at the approximate beginning of the period of Total Residual Chlorine (TRC) and/or Free Available Chlorine (FAC) discharge and once every twenty (20) minutes until TRC or FAC is no longer present.

18. Intake screen wash water, pump strainer backwash water, fire protection water, and potable water systems may be discharged without limitations or monitoring requirements. Appropriate measures shall be taken to minimize any impact to the environmental.

19. The permittee shall not store coal, soil nor other similar erodible materials in a manner in which runoff is uncontrolled, nor. conduct construction activities in a manner, which produces uncontrolled runoff unless such uncontrolled runoff has been specifically approved by SCDHEC. "Uncontrolled" shall mean without sedimentation basin or other controls approved by SCDHEC.

l I-l I PART III Page 27 of 27 Permit No. SC0004278

20. Upset - (1) Definition. "Upset" means an exceptional incident in which there is unintentional and temporary noncompliance with technology based permit effluent limitations because of factors beyond the reasonable control of the permittee. An upset does not include noncompliance to the extent caused by operational error, improperly designed treatment facilities, inadequate treatment facilities, lack of preventive maintenance, or careless or improper operation.

(2) Effect of an upset. An upset constitutes an affirmative defense to an action brought for noncompliance with such technology based permit effluent limitation if the requirements of paragraph (3) of this section are met. No determination made during administrative review of claims that noncompliance was caused by upset, and before an action for noncompliance, is final administrative action subject to judicial review. (3) Conditions necessary for a demonstration of upset. A permittee who wishes to establish the affirmative defense of upset shall demonstrate, through properly signed, contemporaneous operating logs, or other relevant evidence that: (i) An upset occurred and that the permittee can identify the cause(s) of the upset; (ii) The permitted facility was at the time being properly operated; and (iii) The permittee submitted notice of the upset as required in paragraph Part II.B.2 of this permit (24 hour notice). (iv) The permittee complied with any remedial measures required by Part II.C.3 of this permit (duty to mitigate). (4) Burden of proof. In any enforcement proceeding, the permittee seeking to establish the occurrence of an upset has the burden of proof.

21. The once through noncontact cooling water system may be drained without limitations or monitoring requirements for maintenance activities provided that the Catawba Nuclear Station takes proper measures to minimize environmental impact from this activity.

22. The permittee shall upon request make available for review and comment the test procedures for the analysis of parameters regulated by the permit which the State does not issue laboratory certification.

23. The permittee shall monitor and report the total recoverable copper levels at Outfall 001 at a frequency of once per month for a period of two (2) years If after two (2) years of monitoring, it is determined that a total copper limitation is appropriate, the permit will be reopened and a limitation established with Schedule of Compliance if deemed necessary. If it is shown that a total copper limit is not necessary, then the monitoring requirement will be eliminated.

24. The permittee shall monitor and report the temperature at Outfall 006 for a period of one (1) year.

After one (1) year of monitoring, a report summarizing the sample results shall be submitted to the Department to be evaluated and to determine if a limit needed. If the monitoring data shows that a limitation is appropriate, the permit will be reopened and a limitation established.

Rationale Page l of 47 Permit No. SC0004278 Duke Energy Co./Catawba Nuclear Station NPDES Permit No. SC0004278 Permitting Engineer. Timothy M. Ekazer Facility Rating: Major m (EPA review required) Minor a (EPA review may be required; see below) Permit application included in Attachment 1. Facility Address: 4800 Concord Road, York, South Carolina 29745 (see map, 'Attachment 2) County: York Watershed: Basin 03 (Catawba-Santee River Basin) .:,~ May.24,2005 Primary Industry Categories Adhesives and sealants Aluminum forming" Auto and other laundries

Battery manufacturing, Coal mining Coi coating';

Copper forming Electrical and electronic components Electroplating Explosives manufacturing Foundries Gum and wood chemicals inorganic chemicals manufacturing Iron and steel manufacturing Leather tanning and finishing Mechanical products manufacturing Nonferrous metal manufacturing Ore mining Organic chemicals manufacturing Paint and ink formulation Pesticides Petroleum refining A II44rU&4rUff i rd5LIAIfan Issuance (New) a] Reissuance D] Modification CD If this application is for a new facility or expansion of an existing facility, an antidegradation review may be required per the requirements of R.61-68.D. Facility Description (include SIC, code): This facility is a Nuclear Power Plant Generating Electric Power.-' SIC Code is 4911 Outfalls are discussed in Section m of this rationale with a general 'description of Photographic equipment and's the discharge, treatment system, stream flows and other'pertinent information'abbut Plastics processing each outfall. 'a' Plstic. 'and synthetic ,manufacturing Porcelain enameling -HIs any discharge subject to any of the Primary Industry Categories identified in Pritint andpmublishing R.61-9.122, Appendix A as listed at right? Yes (Ifyyes, EPA reviewreqqiiired.)

• Pulp and paper mills Indicate category(ies) applicable and Regulations'governing the discharge: Steamr Rubber processing Electric Power Generating Point Source Category, 40 CFR Part 423' Soap and detergent manufau Steam electric power plants Receiving Water: 001, 002, 003, 004, 005 and 006,- discharge to Lake Wylie TextileMills Receiving Water Classification (see R.61-69 for water classifications): Fresh Water

-+Does any dischargers) have the potential to affect waters in another'state? No (If yes, EPA ieview required.) upplies M ring. aterials Is any discharge to Impaired Waters?: Yes If Yes, list the monitoring station number and parameterfs) causing impairment: CW-027, fecal coliform and CW-1 97, Copper. l-Average Discharge Flow from outfall with largest average flow: (Qd) (MGD): 82 (from permit application) (EPA review required for any average discharge exceeding 0.5 MGD) -41s this permit for a Federal facility with a daily average flow greater than 0.05 MGD (from all sources)? No- (If yes, EPA review required.) Data from Discharge Monitoring Reports (DMRs) and NPDES permit application (including all subsequent data presented) from 6/1/2001 - 5/1/2005 has been used to evaluate permit limitations.

'e Rationale Page 2 of 47 Permit No. SC0004278 I. GENERAL INFORMATION A. The effluent from this facility may be subject to the requirements of any of the following regulations: R.61-9.125, 129, 133, and 403; 40 CFR Part 136; Subchapter N (40 CFR Parts 400 through 402 and 404 through 471); R.61-9.503, R.61-9.504 and R.61-9.505. B. Authority: This permit is written in accordance with applicable laws and regulations including, but not limited to, Regulation 61-9, Regulation 61-68, Pollution Control Act and Clean Water Act. C. Under R.61-9.124.8 (Fact Sheet), a fact sheet shall be prepared for every draft permit for a major NPDES facility or activity, for every Class I sludge management facility, for every NPDES draft permit that incorporates a variance or requires an explanation under section 124.56(b), and for every draft permit which the Department finds is the subject of wide-spread public interest or raises major issues. D. The conclusions noted in the Rationale establish proposed effluent limitations and permit requirements addressed in R.61-9.122.43 (Establishing Permit Conditions), R.61-9.122.44 (Establishing Limitations, Standards and other permit conditions) and other appropriate sections of R.61-9. II. RATIONALE GUIDANCE PROCEDURES A. The receiving waterbody 7Q10, annual average flow or other critical flow condition at the discharge point, and 7Q1 0, annual average flow, or other critical flow condition at the boundary of the source water protection area above a proposed or existing drinking water intake (if applicable) are determined by the SCDHEC's Wasteload Allocation Section. The 7Q10, Annual Average Flow or other critical flow conditions are based on information published or verified by the USGS, an estimate extrapolation from published or verified USGS data or from data provided by the permittee. These flows may be adjusted by the Wasteload Allocation Section to account for existing water withdrawals that impact the flow. The 7Q10 (or 30Q5 if provided by the applicant), annual average flow at the discharge point, or other critical flow condition or 7Q10 (or 30Q5 if provided by the applicant), annual average flow or other critical flow condition at the boundary of the SWP area for a proposed or existing drinking water intake will be used to determine dilution factors, as appropriate, in accordance with R.61-68.C.4.a & 4.b for aquatic life, human health, and organoleptic effects respectively. B. Water and organism consumption and drinking water MCL data will be evaluated as human health values when calculating dilution factors. "The Department may, after Notice of Intent included in a notice of a proposed NPDES permit in accordance with Regulation 61-9.124.10, determine that drinking water MCLs or W/O shall not apply to discharges to those waterbodies where there is: no potential to affect an existing or proposed drinking water source and no state-approved source water protection area." For permitting purposes, a proposed drinking water source is one for which a complete permit application, including plans and specifications for the intake, is on file with the Department at the time of consideration of an NPDES permit application for a discharge that will affect or has the potential to affect the drinking water source." See R.61-68.E.14.c(5). The Department defines the source water protection (SWP) area to be the primary SWP area delineated by the Source-Water Assessment and Protection (SWAP) Program initiated by the EPA and required by the states to identify SWP areas to protect drinking water sources. Using the procedure described in the document entitled, "Determination of the Primary and Secondary Source-Water Protection Areas for Selected Surface-Water Public-Supply Systems in South Carolina, 1999," USGS Water Resource Investigations Report 004097, the primary SWP area for a drinking water intake is the area which encompasses all 14-digit Hydrologic Unit Code (HUC) basins that adjoin streams, tributaries, and reservoirs between an intake and the upstream 10-percent exceedance, 24-hour travel distance (TOTo). The entire basin above a drinking water intake has been designated as the SWP area where the drainage area is equal to or less than one HUC basin or is estimated to have less than 24-hours of instream travel time between the intake and the HUC basin in the headwaters of the drainage basin.

Rationale Page 3 of 47 Permit No. SC0004278 C. Application of numeric criteria to protect human health: If separate numeric 'criteria are given for organism consumption, water and organism consumption (W/O), and drinkdng water Maximum Contaminant Levels (MCLs), they shall be applied as appropriate.' The most stringent of the criteria shall bi applied to protect the existing and classified uses of the waters of the State. See R.61-68.E.14.b(1). D. Numeric criteria have been established in R.61-68 based on cr'anoleptic data (prevention of undesirable taste and odor). For those substances which have aquatic life and/or human health numeric criteria and organoleptic numeric criteria, the most stringent of the three shall be used for derivation of permit effluent limitations. See R.61-68.E.13. E. Sampling Frequency: Saimples and measurements 'taken for the purpose of monitoring shall be representative of the monitored activity. Monitoring results must be conducted according to test procedures approved under 40 CFR Part 136, unless other test procedures have been specified in the permit (R.61-9.122.41). Typically requirements to report monitoring results shall be established on a case-by-case basis with a frequency dependent on the nature and effect of the discharge but in no case less than once a. year (R.61-9.122.44) F. Compliance Schedules:

1. A person issued an NPDES permit by the Department who is not in compliance with applicable effluent standards and limitations or other requirements contained therein at the time the permnit is issued, shall be required to achieve compliance within a period of time as set forth by the Department, with effluent standards and limitations, with water quality standards, or with specific requirements or conditions set by the Department.

The Department shall require compliance with terms and conditions 'of the permit in the shortest reasonable period of time as determined thereby or within a time schedule for compliance which shall be specified in the issued permit.

2. If a time schedule for compliance specified in an NPDES permit'which is established by the Department, exceeds'nine (9) months, the time schedule'shall provide for interim dates of achievement for compliance with certain applicable terms and conditions of thepermit. (R.61-9.122.47);

G. Procedure for establishing effluent limitations: I. Effluent iimits (mass and concentration) for Five day Biochemical Oxygen Demand '(BODe), Ultimate Oxygen Demand (UOD), Dissolved Oxygen' (DO), Total -Amunionia Nitrbgen (as N), and Nutrients are established by the Wasteload Allocation (WLA) Section, with consideration 'given to technology-bised limitations.

a. Five day Biochemical Oxygen Demand BODS Ultimate Oxygen 'Demand (UOD), Dissolved Oxygen (DO):

Effluent limits for conventional oxygen deraniding constituents (BOD5', UOD'and DO) are established to protect in-stream water quality and uses,bwhile utilizing a portion of the assimilative capacity of the receiving water. The ability of a water body to assimilate oxygen-demanding substances is a function of its physical and chemical characteristics above and below the'discharge point. Various mathematical techniques, called models, have been developed'pto estimate this capacity. The Department follows the procedures as'outlined in the "State/EPA Region IV Agreement on the'Development of Wasteload Allocations/Total Maximum Daily Loads and NPDES Permit Limitations" dated October 30, 1991 (as updated) for determining the'assimilative capacity of a given water body. Mathematical models such as QUAL2E and QUAL2E-UNCAS are used in accordance with "Enhanced Stream Water Quality Models QUAL2E and QUAL2E-UNCAS: Documentation and Users Manual" (EPAI600/3-87/007; dated May 1987) as updated. BOD' and UOD values determined from modeling results will be used in permitting as

LL Rationale Page 4 of 47 Permit No. SC0004278 monthly average derived limits (C*). Daily maximum derived limits will typically be determined by multiplying the monthly average value by two. For facilities subject to effluent guidelines limitations or other technology-based limitations, BOD5 will also be evaluated in accordance with the applicable industrial categorical guidelines. These parameters will be identified in Part III of this rationale when they are applicable to the permit.

b. Total Ammonia Nitrogen (as N):

Ammonia limitations based on oxygen demand will be determined from modeling information as described above. These values will be used as monthly average derived limits and a daily maximum will typically be determined by multiplying the monthly average derived limit by two. These values will be compared with the ammonia water quality criteria for protection of aquatic life from Regulation 61-68, Attachment 3 and any categorical limitations. The more stringent of the limitations will be imposed. Calculations for aquatic life criteria and other wasteload recommendations will be shown later in Part Im of this rationale when ammonia is a pollutant of concern.

c.

Discharges of Nutrients: In order to protect and maintain lakes and other waters of the State, consideration is given to the control of nutrients reaching the waters of the State. Therefore, in accordance with regulation R.61-68.E. II, the Department controls the nutrients as prescribed below. Nutrient limitations will be determined from the best available information and/or modeling performed by the Wasteload Allocation Section to meet these water quality standards.

i. Discharges of nutrients from all sources, including point and nonpoint, to waters of the State shall be prohibited or limited if the discharge would result in or if the waters experience growths of microscopic or macroscopic vegetation such that the water quality standards would be violated or the existing or classified uses of the waters would be impaired. Loading of nutrients shall be addressed on an individual basis as necessary to ensure compliance with the narrative and numeric criteria.

ii. Numeric nutrient criteria for lakes are based on an ecoregional approach which takes into account the geographic location of the lakes within the State and are listed below. These numeric criteria are applicable to lakes of 40 acres cr more. Lakes of less than 40 acres will continue to be protected by the narrative criteria. I. for the Blue Ridge Mountains ecoregion of the State, total phosphorus shall not exceed 0.02 mg/l, chlorophyll a shall not exceed 10 ug/l, and total nitrogen shall not exceed 0.35 mg/I

2. for the Piedmont and Southeastern Plains ecoregions of the State, total phosphorus shall not exceed 0.06 mg/I, chlorophyll a shall not exceed 40 ug/l, and total nitrogen shall not exceed 1.50 mg/l

3. for the Middle Atlantic Coastal Plains ecoregion of the State, total phosphorus shall not exceed 0.09 mg/I, chlorophyll a shall not exceed 40 ug/l, and total nitrogen shall not exceed 1.50 mg/l.

iii. In evaluating the effects of nutrients upon the quality of lakes and other waters of the State, the Department may consider, but not be limited to, such factors as the hydrology and morphometry of the waterbody, the existing and projected trophic state, characteristics of the loadings, and other control mechanisms in order to protect the existing and classified uses of the waters.

Rationale Page 5 of 47 Permit No. SC0004278 iv. The Department shall take appropriate action, to include, but not limited to: establishing numeric effluent limitations in permits, establishing Total Maximum Daily Loads, establishing waste load allocations, and establishing load allocations for nutrients to ensure that the lakes attain and maintain the above narrative and numeric criteria and other applicable water quality standards.

v. The criteria specific to lakes shall be applicable to all portions of the lake. For this purpose, the Department shall define the applicable area to be that area covered when' measured at full pool elevation.

2. Effluent concentration limits (Cffl,,,) for parameters other than the parameters listed in G.L.a-c above are established using the following procedures:

Q'I0 -7Q10 or other critical flow condition of the receiving water at the discharge point in mgd. (may require adjustment for withdrawals) AAF* Average Annual Flow (AAF) or other. critical flow condition of the receiving water at the discharge point in mgd. (mnay require adjustment for withdrawals) Qiozoi 7Q10 or other critical flow condition of the receiving water at the SWP Area boundary in mgd.

AAF, Average Annual Flow (AAF) of the receiving water at the SWP Area boundary in mgd.

Q. Long term average discharge flow in ingd.

a. Determine dilution factors:

The following infornation is to be used (where applicable) for establishing effluent concentration limits: DF,: Dilution factor based on 7Q10 or other critical flow condition of the receiving water at the discharge point (Q,,). This dilution factor is used to determine the derived limits for protection of the following aquatic life and human health concerns for the reasons indicated:

i.

Aquatic Life (see R.61-68.C.4.a(l)). Protection of aq uatic life on a short-term basis is needed at the point where aquatic organisms become exposed to the discharge. ii. Human Health - Organism Consumption.for parameters;identified as non-carcinogens per R.61-68.C.4.b(l). Protection for-humanivhealth on a short-term.basis for consumption of -. aquatic organisms is needed at the point;the aquatic organisms become exposed to the discharge. -~Q (e3 : DF,= QQ;d, DF2: ; Dilution factor, at the discharge point, based on the Average Annual Flow of the receiving water at the discharge point (AAFdj. This dilution'factor is used'to determine the derived limits for protection of the following human health and organoleptic concerns for the reasons indicated:

i. Human Health - Organism Consumption for parameters identified as carcinogens per R.61-68.C.4.b(l). Protection for human health -on a long-term basis to prevent cancer due to consumption of aquatic organisms is needed at the point the aquatic organisms become exposed to the discharge where it enters the receiving water.

ii. Organoleptic effects per R.61-68.C.4.b(l). Protection for taste and odor issues related to the

lU Rationale Page 6 of 47 Permit No. SC0004278 discharge is needed at the point where the discharge enters the receiving water. DF2 = IAAFd + Qd Qd ) DF,: Dilution factor based on the 7Q10 or other critical flow condition at the source water protection area boundary for protection of a proposed or existing water intake downstream of the discharge (Q7Q~'l). This dilution factor is used to determine the derived limits for protection of the following human health concerns for the reasons indicated:

i.

Human Health - Water and Organism Consumption for parameters identified as non-carcinogens per R.61-68.C.4.b(l) and E.14.c(5) to protect for short-term health effects when the discharge is above any drinking water intake. Protection of human health relative to drinking the water from the waterbody and consuming aquatic organisms from the same waterbody is provided by this criterion, but drinking the water withdrawn from the waterbody may require a potentially higher level of protection in terms of applicable dilution than consumption of organisms. In addition, to satisfy the requirements of R.61-68.C.10(a), the Department has determined that dilution at the boundary of the Source Water Protection area will protect the drinking water intake to meet this requirement. For discharges affecting the primary SWP area, dilution will be determined using the largest TOT,1 flow along the SWP area boundary upstream of the drinking water intake of concern. If multiple drinking water intakes are present below the discharge, the SWP area of the intake closest to the discharge will be protected. If the entire basin is designated as the SWP area, the boundary will be the TOT,O at the beginning of the basin, even if it is outside the State boundaries (e.g. North Carolina). ii. Human Health - Drinking Water Maximum Contaminant Level (MCL) for parameters identified as non-carcinogens per R.61-68.C.4.b(l) and E.14.c(5) to protect for short-term health effects when the discharge is above any drinking water intake. Protection of human health relative to drinking the water from the waterbody after conventional treatment per R.61-68.G is provided by this criterion. In addition, to satisfy the requirements of R.61-68.C.10(a), the Department has determined that dilution at the boundary of the Source Water Protection area will protect the drinking water intake to meet this requirement. For discharges affecting the primary SWP area, dilution will be determined using the largest TOTO flow along the SWP area boundary upstream of the drinking water intake of concern. If multiple drinking water intakes are present below the discharge, the SWP area of the intake closest to the discharge will be protected. If the entire basin is designated as the SWP area, the boundary will be the TOTo at the beginning of the basin, even if it is outside the State boundaries (e.g. North Carolina). DF = ('Q7Qi + Qd 3 Qd ) DF,: Dilution factor based on the Average Annual Flow at the source water protection area boundary for protection of a proposed or existing water intake downstream of the discharge (AAF,).

! 5 -Rationale Page 7 of 47 Permit No. SC0004278 This dilution factor is used to determine the derived limits for protection of the following human health concerns for the reasons indicated:

i.

Human Health-Water and Organism Consumption for parameters identified as carcinogens per R.61-68.C.4.b(l) and E.14.c(5) to protect for long-term health effects due to cancer when the discharge is above any drinking water intake. Protection of human health relative to drinking the water from the waterbody and consuming aquatic organisms from the same waterbody is provided by this criterion, but drinking the water withdrawn from the waterbody may require a potentially higher.level of protection in terms of applicable dilution than consumption of organisms. In addition, to satisfy the requirements of R.61-68.C.10(a), the Department has determined that dilution at the boundary of the Source Water Protection area will protect the drinking water intake to meet this requirement. For discharges'affecting the primary SWP area, dilution will be determined using the largest TOT,0 flow along the SWP area boundary upstream of the drinking water intake of concern. If multiple drinking water intakes are present below the' discharge, the SWP area of the intake closest to the discharge'will be protected.-; If the entire basin is designated as the SWP area, the boundary will be the TOTo at the beginning of the basin, even if it is outside the State boundaries (e.g. North Carolina). ii. Human Health - Drinking Water'Maximum Contaminant Level (MCL) for parameters identified as carcinogens per R.61-68.CA.b(l) and E.14.c(5) to protect for long-term health effects due to cancer when the discharge is above any drinking water intake. Protection of human health relative to drinking the water from the waterbody and consuming aquatic organisms from the same waterbody is provided by this criterion, but drinking the water withdrawn from the waterbody may require a potentially higher level of protection in terms of applicable dilution than consumption of organisms. In addition, to satisfy the requirements of R.61-68.C.10(a), the Department has determined that dilution at the boundary of the Source Water Protection area will protect the drinking water intake to meet this requirement. For discharges affecting the primary SWP area, dilution will be determined using the largest TOTC flow along the SW? area boundary upstream of the drinking water intake of concern. If multiple drinking water intakes are present below the discharge, the SWP area of the intake closest to the discharge will be protected. If the entirebain'is 'designated as the SWP area, the boundary will be. the TOTIO at thle beginning of the 'basin, even if it is outside the State boundaries (e.g. North Carolina).

• d (MQ. J v

-d

b. Determine monthly average derived lirmits using the following procedures:

WQS, Freshwater Standard (based on an established criteria or other published data per R.61-68) for protection of Aquatic Life; may be a CCC or CMC as defined below WQSOZ Standard (based on an established criteria or other published data per R.61-68), for protection of Human Health - Organism Consumption WQS. Standard (based on an established criteria or other published data per R.61-68), for protection of Human Health - Water & Organism Consumption. Applicable only if any portion of the mixing zone for this discharge is in a state-approved source water'protection area for a proposed or existing water intake downstream of the discharge point.

11 L U Rationale Page 8 of 47 Permit No. SC0004278 WQS.4 Standard (based on an established criteria or other published data per R.61-68), for Drinking Water MCL (Maximum Contaminant Lcvel). Applicable only if any portion of the mixing zone for this discharge is in a state-approved source water protection area for a proposed or existing water intake downstream of the discharge point. WQSd: Standard (based on an established criteria or other published data per R.61-68), based on Organoleptic Data. C,,9,e Concentration limit derived from aquatic life data CHH Concentration limit derived from human health data as determined from organism (CO), water/organism (C,,)and MCL (Cd) data CO4 Concentration limit derived from organoleptic data Cb Background concentration of the concerned parameter in mg/I is typically determined from ambient monitoring data or data provided by applicant. The 90' percentile of ambient monitoring data for aquatic life protection for the parameters identified in the Appendix (Water Quality Numeric Criteria) to Regulation 61-68 from the last 3 years, or whatever is available if less than 3 years, will typically be used per the procedures used for 303(d) listing. The median value of ambient monitoring data for human health protection for the parameters identified in the Appendix (Water Quality Numeric Criteria) to Regulation 61-68 from the last 3 years, or whatever is available if less than 3 years, will typically be used per the procedures used for 303(d) listing. The background concentration is assumed to be zero (0) in the absence of actual data based on Departmental guidance and EPA recommendation.

i.

Determine the derived limit for protection of Aquatic Life (C.,10)

1. The following guidelines apply to determining aquatic life limits:

a. Typically, the Criterion Maximum Concentration (CMC) is applied as a daily maximum derived limit and the Criterion Continuous Concentration (CCC) is applied as a monthly average derived limit, after consideration of dilution and background concentrations.

Exceptions exist based on EPA criteria and are indicated for specific parameters. The CMC and CCC for specific metals will be adjusted using the procedures in 60 FR 22229, "Water Quality Standards; Establishment of Numeric Criteria for Priority Toxic Pollutants; States' Compliance-Revision of Metals Criteria," May 4, 1995 and the "Technical Guidance on Interpretation and Implementation of Aquatic Life Metals Criteria," Oct. 1, 1993 and applied as a daily maximum and monthly average, respectively, after consideration of dilution and background concentrations.

b. If only a CMC exists for a particular parameter, a daily maximum derived permit limit only (no monthly average) will be set using that value, after consideration of dilution and background concentrations. If only a CCC is given, it will be used as a monthly average derived limit and the daily maximum derived limit will be two (2) times the value obtained for the monthly average based on a simplified statistical procedure for determining permit limits recommended in Section 5.4.2 of the US EPA's "Technical Support Document for Water Quality-based Toxics Control", EPA/505/2-90-001, March 1991 (hereafter known as the TSD).

c. If only an acute toxicity effect concentration for a number of species for a particular pollutant is given as a LC50, the lowest concentration should be divided by an acute-to-chronic ratio (ACR) of 10 and a sensitivity factor of 3.3, for an acceptable instream concentration in order to protect against chronic toxicity effects (from R.61-68.E.16.a(1)). Other acute toxicity data will be handled similarly. The value obtained from this calculation will be used as a monthly

Rationale Page9of47 Permit No. SC0004278 average derived limit after consideration of dilution and background concentrations. The daily maximum will; be two (2) times the value obtained for the monthly average based on a simplified statistical procedure for determining permit limits recommended in Section 5.4.2 of the TSD.

d. If a chronic toxicity effect concentration for a number of species for a particular pollutant is given as a no observed effect concentration (NOEC), the lowest concentration should be divided by a sensitivity factor of 3.3 in order to protect against chronic toxicity to the most sensitive species (from R.61-68.E.16.a(2)). Other chronic toxicity data will be handled similarly. The value obtained from this calculation will beused as a monthly average derived limit after consideration of dilution and background conceltrations. The daily maximum will be two (2) times the value obtained for the monthly.average based on a simplified statistical procedure for determining permit linits recommended in Section 5..2 of the TSD.

e. If both acute and chronic data are available for a particular pollutant, monthly average derived limit will be calculated as in c and d above for each acute and chronic, respectively. The more stringent of the monthly average derived limits will be the monthly average derived limit used after consideration of dilution and background conicentrations. The daily maximum will be two (2) times the value obtained for the monthly. average based on a simplified statistical procedure for determining pennit limits recommended in Section 5.4.2 of the TSD.

2. Consider the background concentration (Cb),of.the parameter of concern. If the background concentration is equal to or greater than the applicable standard (WQS, as defined above) for the parameter of concern, then the derived concentration limit (C.u) for that parameter and for the protection of that standard, is established equal to the standard (WQS). An exception exists where the naturally occurring instream concentration for, a substance is higher than the derived permit effluent limitation. In those situations, the Department may establish permit effluent limitations (C<p,,) at a level higher -than the derived limit, but.no higher than the natural background concentration. In such cases, the Department may require biological instream monitoring and/or whole effluent toxicity (WET) testing (See R.61-68.E.14.c(2)). i.e.'

If Cb is not based on naturally occurring concentrations and Cb WQS-Then, generally, 1 C.qlie = If Cb is based on naturally occurring concentrations and C b WQS -Then, generally,; Cqije < Cb Iim Cb. Otherwise, the limits are established as described in Item 3 or 4 below.

3. For the parameters listed in Table A below, Regulation R.61 68.E.14.c(4) provides for the use of the EPA Office of Water Policy and "Technical Guidance on Interpretation and Implementation of Aquatic Life Metals'Criteria", October 1, 1993.' A subsequent revision published in the Federal Register (60 FR 22229) on May 4, 1995:updated the data in the original report. See R.61-68 Attachment I "Conversion Factors for Dissolved Metals" and Attachment 2 "Parameters for

11l l Rationale Page 10 of 47 Permit No. SC0004278 Calculating Freshwater Dissolved Metals Criteria that are Hardness-Dependent". The following equations and constants will be used to calculate aquatic life metals limits based on the Federal Register data. The water quality standard for these metals (CCC or CMC) will also be adjusted using this approach in accordance with Regulation 61-68.E.14.d(3) for evaluation of ambient water quality.

TSS, Effluent Total Suspended Solids (TSS) concentration in mg/I from actual or proposed monthly average permit limits.

TSSb Background or in-stream Total Suspended Solids (TSS) concentration. The background TSS is assumed to be I mg/I in the absence of actual instream data based on the 5th percentile of ambient TSS data on South Carolina waterbodies from 1993-2000. TSS., Average in-stream (mixed) TSS concentration. CF Conversion factor considered most relevant in fresh water for aquatic life as defined by EPA in dissolved metals documents for each listed metal H Hardness in mg/I of CaCO3. Per R.61-68.E.14.a(3), the CMC and CCC are based on a hardness of 25 mg/I if the ambient hardness is less than 25 mg/I. Concentrations of hardness less than 400 mg/I may be based on the actual mixed stream hardness if it is greater than 25 mg/I and less than 400 mg/I and 400 mg/I if the ambient hardness is greater than 403 mg/I. The background hardness is assumed to be 25 mg/I in the absence of actual stream data. Mixed stream hardness may be determined using effluent hardness and actual stream hardness. K,,, Metal-specific equilibrium constant a Metal-specific constant K, Linear partition coefficient K,6 Linear partition coefficient for use in the derivation of an adjusted water quality standard C, Dissolved phase metal concentration C, Total metal concentration S a constant to represent the CCC or CMC The following table lists the values for the constants, the CCC and CMC, and the recommended values of the conversion factors (CF). Table A Parameter kp a CMC CFcmc CCC CFccc I (pg/) I(pg/I) I Arsenic 0.48 x 106 -0.7286 340 100 150 100 Cadmium 4.00 x 106 -1.1307 0.53* 100* 0.10* 96.7* mChromiumn+3 3.36x 106 -0.9304 580* 31.6 28* 86 Chromium+6 3.36 x 106 -0.9304 16 98.2 11 96.2 Copper 1.04 x 106 -0.7436 3.8* 96 2.9* 96 Lead 0.31 x 106 -0.1856 14* 99.3* 0.54* 99.3* Mercury 2.91 x 106 -1.1356 1.6 85 0.91 85 Nickel 0.49 x 106 -0.5719 150* 99.8 16* 99.7 Zinc 1.25 x 106 -0.7038 37* 97.8 37* 98.6

• The equations for calculating the CCC, CMC, and conversion factors are given in the Appendix to Regulation 61-68 and Attachments land 2 for each parameter. The values given for the CMC and CCC and CF in the table are based on 25 milligrarns/liter (mg/i) hardness (as expressed as CaCO3).

From Technical Guidance Manual for Performing Waste Load Allocations Book II. Rivers

Rationale Page. I of 47 Permit No. SC0004278 and Streams, EPA/440/484/022: S =CCC or CMC. Cd =Sx CF To determine the adjusted water quality standard (WQSd,), use S and the equation for Cd above and the following equations: KPb = Kpo X (TSS 6)C WQS., = Cd X + (Kob x TSSb x10 )} To determine the effluent limit (C.,h), use S and the equation for Cd above and the following equations: ( QxTSSO + )+(Q7QIO XTSSb) TSS,. = X Qd + Q7Q910 C= Cd X {1 + (KP XT SSf x10-)' Once C, has been calculated, it is multiplied by DF, and background concentrations are accounted for to obtain the monthly average derived limit (Coqyi,): CC' Q7

4. For all other parameters not included in paragraph 3, Table A, monthly average derived limits (Citjf,) for aquatic life protection are calculated as follows:

C *

• (DFxWQS.)..C...

-C. .k Qd ii. Determine derived limit for protection of Human Health

1. The following guidelines apply to determining human health limits:

a. The' human health criterion given by Regulation 61-68 will be applied as a monthly average derived limit after consideration of dilution and background concentrations (CHN.-

,,,). Exceptions exist based on EPA criteria and are indicated for specific parameters. No limits on human health based on water and organism consumption or drinking water MCLs will be imposed if there is no potential to affect a drinking water intake or source

Il U - Rationale Page 12 of 47 Permit No. SC0004278 water protection area (i.e., if there is no intake downstream of the discharge).

b. The daily maximum permit limit will be determined from the monthly average value from (a) above and a multiplier (M) determined using a statistical procedure recommended in Section 5.5 using average = 95" percentile from Table 5-3 in the TSD. The permitted or proposed number of samples per month (n) is used with the coefficient of variation (CV) to determine M. CV is assumed to be 0.6 as a default value if information is not known.

eZ (u~-O.5 2) M Z,,e-0.5ar ) where: 2 =n(CV2 + I a' 2= In(CV2 + 1) CV = coefficient of variation of the effluent concentration = Mean n = the number of effluent samples per month (where frequency is less than I/month, n =1)

z. = the percentile exceedance probability for the daily maximum permit limit

(=2.326 for 99h percentile basis)

z. = the percentile exceedance probability for the monthly average permit limit

(=1.645 for 95" percentile basis) CH..^, = M

• CHH.,

2. Consider the background concentration (Cb) of the parameter of concern. If the background concentration is equal to or greater than the applicable standard (WQS, as defined above) for the parameter of concern, then the derived concentration limit (CH,) for that parameter and for the protection of that standard, is established equal to the standard (WQS). An exception exists where the naturally occurring instream concentration for a substance is higher than the derived permit effluent limitation. In those situations, the Department may establish permit effluent limitations (Cej.) at a level higher than the derived limit, but no higher than the natural background concentration. In such cases, the Department may require biological instream monitoring and/or whole effluent toxicity (WET) testing (See R.61-68.E.14.c(3)).

If Cb is not based on naturally occurring concentrations and C b 2 WQS Then, generally, CHH = WQS. If Cb is based on naturally occurring concentrations and C b 2 WVQS Then, generally, CH < Ceff lim Cb

Rationale Page 13 of 47 Permit No. SC0004278 Otherwise, the limits are established as described in Items 3-6 below.

3. Human Health - Organism Consumption (C.,).

a. For Carcinogens The Monthly Average is calculated as follows:

Corg = (DF2 X WQSo )-{Cb X (AF )

• b. For Non-carcinogens The Monthly Average is calculated as follows:

Crg = (DFE x WQSorg) -{Cbx(i)}

4. Human Health - Water and 'Organism Consumption (C.)

a. 'For Carcinogens The Monthly Average is calculated as follows:

C.,o (DF4 XWQS ~)-{Cb X()}

b. For Non-carcinogens The Monthly Average is calculated as follows:

Cb =(DF3 XWQS) -Q{CbX( 7QIJ}

5. Human Health - Drinking Water Maximum Contaminant Level (MCL) (Cd).

a. For Carcinogens,

The Monthly Average is calculated as folows:" CMCI= (D 4 X WQSe't)-{Cb( X A 1J { Qd ) b., ForNon-carcinogens The Monthly Average is calculated as follows: = (DF3 x WQS ) {Cbx(Q'J}

6. Organoleptic criteria (C.,).

The Monthly Average is calculated as follows:

11 H Rationale Page 14 of 47 Permit No. SC0004278 C., =(DF2X WQS. 1) {Cb X(AA J} i (Qd )

c.

Determine most stringent of applicable data using the monthly average derived limits determined or calculated above: C," = minimum of (C,,,,,, CO., C-l, Cd,, Ci Cl.) Note: If a CMC is present for the parameter of concern, the daily maximum derived limit obtained from that calculation must also be considered under reasonable potential.

d. Determine whether the discharge causes, has the reasonable potential to cause or contributes to a water quality violation.

Regulation 61-9.122.44(d)(1Xi) states: "Limitations must control all pollutants or pollutant parameters (either conventional, nonconventional, or toxic pollutants) which the Department determines are or may be discharged at a level which will cause, have the reasonable potential to cause, or contribute to an excursion above any State water quality standard, including State narrative criteria for water quality." When determining whether a discharge causes, has the reasonable potential to cause or contributes to an instream excursion, the Department will use procedures which account for controls on point and nonpoint sources of pollution, the variability of the pollutant in the effluent, the sensitivity of the species to toxicity testing (when evaluating whole effluent toxicity), and, where appropriate, the dilution of the effluent in the receiving water (R.61-9.1 22.44(d)(1)(ii)). Based on the above statements, there are three scenarios when limitations are required, as follows:

i.

When data provided by the permit applicant indicates values greater than the proposed limitation derived above, that discharge will cause an excursion above a narrative or numeric water quality criterion. ii. A discharge will be determined to contribute to an excursion of a water quality criterion when the waterbody is impaired (e.g., on the 303(d) list) for the parameter of concern and that parameter is also being discharged at levels above the water quality criterion. iii. Reasonable potential to cause a water quality violation is determined using the following information: Chapter 3 of the TSD provides information for determining the need for permit limits based on the regulatory statements above. A statistical procedure is also presented in Chapter 3 for use in determining reasonable potential from effluent data. Other statistical methods may be used as well to evaluate data sets. "National Guidance for the Permitting, Monitoring, and Enforcement of Water Quality-Based Effluent Limitations Set Below Analytical Detection/Quantitation Level" draft dated March 22, 1994, offers recommendations on how to interpret data below detection capabilities to make a reasonable potential analysis. All pollutants given in a wasteload allocation or an effluent limitation guideline will be limited in the permit.

Rationale Page 15 of 47 Permit No. SC0004278 When effluent data consists of non-quantifiable/non-detectable values or when no effluent data is available, other factors and information are considered to determine reasonable potential. In situations where a pollutant is known to be present in'the wastestreani (due to production data or other information), we know it is being discharged and has the potential to impact even though it may not be quantifiable. The fact that it is present will be'enough information to say reasonable potential exists for that pollutant. Therefore, a reasonable potential decision is based on various data and infornation, and not just non-quantifiable/non-detectable data. Consideration is given to existing data, dilution in the waterbody, type of receiving water, designated use, type of industry/wastestream, ambient data, history of compliance, and history of toxic impact. If any source of information indicates reasonable potential to cause or contribute to an exceedance of the water quality standard, a water quality limit will be developed. Note: The result of the following calculations may indicate that reasonable potential does not exist. However, as stated above, other information may "override" this numerical determination to justify the need for a limit.

1. The procedure for determining reasonable potential from actual effluent data is explained in Box 3-2 on page 53 of the TSD. Multiplying factors' are determined from Table 3-2 at a 95%

confidence level and 95% probability in Section 3.3.2. The following describes the procedures used for determining-reasonable potential for chemical-specific parameters and WET, under certain circumstances. More information on determining reasonable potential for WET is given in -Item 2 below. Step l: Data Analysis: The statistical calculations involved in' the "Reasonable Potential" analysis require discrete numerical data. The following describes how the effluent data will be used in determining reasonable potential. Actual analytical results should be used whenever possible. Results less than detection and quantification should be used as follows:

a. If the permittee reports results below the practical quantitation limit (PQL) (as defined by the permit), then the reported "less than PQL" value 'for a given sample is generally assumed to be zero.

b.' If the pernittee uses a detectioi/quantification level that is greater than the PQL, then the reported "less than" value for a given sample'is generally assumed to be a discrete value equal to the detection/quantification level used by the permittee.

c. If the reported data consists'of both 'discrete and non-discrete values and/or the data is reported using varying detection/quantification levels, then, generally, a combination of the above two approaches is used, or the data is evaluated in a manner that is most appropriate for that data set.

Note: For information on the acceptable analytical methods and PQLs please refer to -NPDES permit application attachment titled "Practical Quantitation Limits (PQL) and Approved Test Methods." Step 2: Using data from the permit'application, other data supplied by the applicant and/or Discharge Monitoring Report'(DMR) data, determine the total number of observations (n) for a particular set of effluent data and determine the highest value (C.) from that'data set. For the monthly

II Rationale Page 16 of 47 Permit No. SC0004278 average comparison, the data set will include monthly average results and n will be the number of months in which they sampled in the time period being evaluated. When there is also a daily maximum comparison, the data set will include daily maximum results and n will be the total number of samples in the time period being evaluated. Ian4ad results may not necessarily be used in the calculation. Step 3: Determine the coefficient of variation (CV) for the data set. For a data set where n>10, the CV is calculated as standard deviation divided by mean for the data set being evaluated. For data set where n<10, the CV is estimated to equal 0.6. For less than 10 items of data, the uncertainty in the CV is too large to calculate a standard deviation or mean with sufficient confidence. CV=0.6 for n<10 CV=- 1 for n>l0 where: a- = Standard Deviation of the samples ,u = Mean of the samples Step 4: Determine the appropriate multiplying factor (MF) from either Table 3-2 or using the formulae in Section 3.3.2 of the TSD.

a. Determine the percentile represented by the highest concentration in the sample data.

pn = (I - Confidence Level)l" where: p. Percentile represented by the highest concentration in the data n = number of samples Confidence Level = 0.95 i.e. 95%

b. Determine the multiplying factor (MF), which is the relationship between the percentile described above (C,) and the selected upper bound of the lognormal effluent distribution, which in this case will be the 95th percentile (C,,).

C9 e(Z95s¢+0.502) MF-95 CO e(Zae+O.5a2 ) where: Z,, is the standardized Z-score for the 95h percentile of the standardized normal distribution = 1.645 Z, is the standardized Z-score for the p^ percentile of the standardized normal distribution.(determined in (b) above) Note: The values of Z-scores are listed in tables for the normal distribution. If using AMicrosoft Excel, this can be calculated using the NORMSlNVfunction. a' = In(CV2 + 1)

Rationale Page 17 of 47 Permit No. SC0004278 a = ln(CV 2 +1) Step 5: Multiply the highest value from the data set'(Cog) by the multiplying factor (MF) determined in Step 4 to obtain the maximum receiving water concentration (RWC). RWC Cux MF Step 6: RWC < Derived monthly average limit (Co) implies that a reasonable potential does not 'exist. RWC > Derived monthly average limit (Cp.) implies that a reasonable potential exists. Note: If a CMC is available for a given parameter, the daily maximum value will be used in addition to the monthly average for a determination of reasonable potential.

2. Reasonable potential for WET may be determined from numerical data using one of the following procedures:

a.

When the effluent data is given in terms of percent effluent as LC50 and/or NOEC values: Step 1: Convert the given LC., and NOEC values to toxic units, UV. for acute data and TU, for chronic data, respectively, using the following formulae: TU. 100 eU=LC5 'U~= '100 NOEC Step 2: Using DMR data or other data provided by the applicant, determine the total number of observations (n) for a'particular set of effluent data and determine the highest value (TUA,, Ox or TUE, tax) from that data set. Step 3: Determine the coefficient of variation (CV) for the data set. For a data set where n>l0, the CV is calculated as standard deviation divided by mean. For data set where n<10, the CV is estimated to equal 0.6. For less than 10 items of data, the uncertainty in the CV is too large to calculate a standard deviation or mean with sufficient confidence. Step 4: Determine the appropriate multiplying factor (MF) from either Table 3-2 or using the formulae in Section 3.3.2. (see iii.l, Step 4 above). Step 5: Multiply the highest value of Q., or TUV, from the data set by the multiplying factor (MF) determined in Step 4 and the dilution at the edge of the mixing zone (the test concentration obtained from mixing zone modeling or demonstration) to obtain the maximum receiving water concentration (RWC) R f'C 'for Acute Toxicity = [TU.,

• MF
• conc. at MZ bounday]

11 11 Rationale Page 18 of 47 Permit No. SC0004278 RWC for Chronic Toxicity = [TU, Frir

• MF
• conc. at MZ boundary]

Step 6: RWC for Acute Toxicity < 0.3TU. implies that a reasonable potential does not exist RWC for Acute Toxicity > 0.3TU, implies that a reasonable potential exists RWC for Chronic Toxicity < 1.0TU, implies that a reasonable potential does not exist R WC for Chronic Toxicity >.OTU0, implies that a reasonable potential exists

b. When pass/fail effluent data only is available and all tests have passed, the Department may be able to determine reasonable potential in a manner similar to Item 1 above assuming the test concentration of interest is greater than or equal to the concentration at which the permittee has tested. If the permittee has not tested at or above the test concentration of interest, the Department cannot say that reasonable potential does not exist, unless perhaps, circumstances related to the discharge have changed. If any failures exist in the data set that cannot be removed, reasonable potential may be determined to exist.

c. Other methods for determining reasonable potential may be used if appropriately justified.

e.

Determine permit limits based on water quality data

i. When the discharge is determined to cause or have the reasonable potential to cause a water quality violation for a particular parameter, except WET, limits are needed. Limits are typically based on the monthly average values calculated from G.2.c above.

However, daily maximum values may be evaluated under reasonable potential under certain circumstances. If reasonable potential exists for either average or maximum derived limits, limits on both are needed per Regulation 61-9.122.45(d).

1. If the monthly average from G.2.c is based on a wasteload allocation for oxygen-demanding pollutants and nutrients and

a. no CMC exists, the water quality limits are monthly average = C.

daily maximum = 2 x C..

b. a CMC exists (for ammonia), the water quality limits are monthly average = C.

and the daily maximum is the most stringent of daily maximum = 2 x C. or daily maximum = C,,,,,,using CMC as WQS in G.2.b.i.3 or 4

2. If the monthly average from G.2.c is based on aquatic life data given as a CCC, if the discharge causes, has the reasonable potential to cause or contributes to a water quality violation based on the monthly average and a CMC also exists for the parameter, the water quality limits are monthly average = C,,v,.using CCC as WQS in G.2.b.i.3 or 4 daily maximum = C, using CMC as WQS in G.2.b.i.3 or 4

3. If the monthly average from G.2.c is based on aquatic life data given as a CCC and if the discharge

Rationale Page 19 of 47 Permit No. SC0004278 does not cause, have the reasonable potential to cause or contribute to a water quality violation for that monthly average, but a CMC also exists for the parameter and the discharge causes, has the reasonable potential to cause or contributes to a water quality violation based on that daily maximum, the water quality limits are monthly average = C., using CCC as WQS in G.2.b.i.3 or 4 daily maximum = C,,using CMC as WQS in G.2.b.i.3 or 4

4. If the monthly average from G.2.c is based on aquatic life data given as a CCC or other acute or chronic data and no CMC exists for the parameter, the-water quality limits are monthly average = C,,v, daily maximum = 2 x C-.

5. If no CMC exists and the monthly average from G.2.c is based on human health (organism, w/o, MCL) data, the water quality limits are monthly average = CHH daily maximum = M x C.m using the calculation for M from G.2.b.ii. ILb

6. If a CMC exists and the monthly average from G.2.c is based on human health (organism, w/o, MCL) data, the water quality limits will be monthly average *-C and the daily maximum will be the most stringent of daily maximum M x C,. using the calculation for M from G.2.b.ii.l.b or daily maximum = C.,,,.using CMC as WQS in G.2.b.i.3 or 4

7. If no CMC exists and the monthly average.from G.2.c is based on organoleptic data, the water quality limits are monthly average = C, daily maximum = M x C0, using the calculation forM from G.2.b.ii.l.b

8. If a CMC exists and.the monthly average from G.2.c is based on organoleptic data, the water quality limits will be monthly average C,

and the daily maximum will be the most stringent of daily maximum = M x C., using the calculation for M from G.2.b.ii.l.b or

--il-Rationale Page 20 of 47 Permit No. SC0004278 daily maximum = C,,,, using CMC as WQS in G.2.b.i.3 or 4

9. If only a CMC exists, then the water quality limits will be no monthly average and daily maximum = C,,,,,,using CMC as WQS in G.2.b.i.3 or 4 ii. If the discharge is determined to cause or have the reasonable potential to cause a water quality violation for WET, permit limitations will be explained in the rationale for that parameter.

iii. If the discharge is determined to contribute to an existing water quality violation, monthly average and daily maximum limits will be set giving no credit for dilution of the receiving water (end-of-pipe limits) based on the criteria in Item I above.

f. Consider Effluent Limitations Guidelines (ELG or Categorical guidelines)

The more stringent of the effluent limitations guidelines average and maximum derived limits and water quality-derived average and maximum limits determined in e above shall be used as permit limits, unless other information indicates more stringent limits are needed as indicated in Section H at the end of this section. Categorical limitations based on mass may first be converted to concentration using the long term average flow of the discharge for both the monthly average and daily maximum calculations, unless the applicable guidelines require use of an alternate flow. I. For Effluent guidelines based on production, limits will be calculated as follows: ELG lim = E (ELGprod)(ELG) where ELGlim: the mass limit, in lbs/day, for an applicable pollutant based on the production ELGprod: the production rate, in Ibs, for the applicable guideline(s), usually based on long term average data ELG: the effluent guideline limitation, given as a measure of production (e.g. Ibs/1000 Ibs), for an applicable pollutant

2. For Effluent guidelines based on flow, limits will be calculated as follows:

ELG lim = j (ELGflow)(ELG)(8.34) where ELGlim :the mass limit, in lbs/day, for an applicable pollutant based on applicable flow ELGprod: the long term average flow rate, in MGD, for the applicable guideline(s) ELG: the concentration limitation, in mg/l, for an applicable pollutant from the applicable guideline(s)

a. For BOD and TSS limits based on OCPSF Effluent Guidelines with two or more applicable subparts in subparts B-H, the limits will be calculated as follows:

ELG 0 = ~( subpart production (ELG lim) where total OCPSF production ELG,: the final OCPSF limitation, in lbs/day ELGlim: the limitation, in lbs/day, determined from the calculation in item 2 above. H. Other considerations

Rationale Page21 of 47 Permit No. SC0004278

1. When the derived permit effluent limitation based on aquatic life numeric criteria is below the practical quantitation limit for a substance, the derived permit effluent limitation shall include an accompanying statement in the permit that the practical quantitation limit using approved analytical methods shall be considered as being in compliance with the limit. Appropriate biological monitoring requirements shall be incorporated into the permit to determine compliance with appropriate water quality standards. (R.61 -

68.E.14.c(2))

2. When the derived permit effluent limitation based on human health numeric criteria is below the practical quantitation limit for a substance, the derived permit effluent limitation shall include an accompanying statement in the permit that the practical quantitation liit using approved analytical methods shall be considered as being in compliance with the limit. (R.61-68.E.14.c(3))

3. The effluent concentration limits determined 'above'may not necessarily be the NPDES permit limit. NPDES Permit limits are determined after a reasonable potential analysis is conducted using these derived limits and also after evaluating other issues (e.g. anti-backsliding, 'antidegradation):-

4. Mass limitations may be required in certain circu'mst'nces.' When mass limits 'are calculated the formula to be used is as follows.

Mass (Ib/day) = Flow (mgd)

• Conceniration (mg/i)
• 8.34.

5. Final Limitations will typically be rounded to two (2) significant figures (based on EPA's -policy with its national criteria) while consideniin-gthe PQL for a given parameter.- Rounding will be performed using the following procedure (as recommended by the DHEC lab):

a. If the digit of interest is even and the number following it is a five (5), 'the digit of interest remains the same.

b. If the digit of interest is odd and the number following it is a five (5), the digit of interest is rounded up.

c. If the digit of interest is even or odd and thefnumber following it is between 0 and 4, the digit of interest remains the same.

d. If the digit of interest is even or odd and the number 'followingit is between6 and 9, the digit of inierest is rounded up.

Rationale Page 22 of 47 Permit No. SC0004278

m. PERMIT LIMITATIONS AND MONITORING REQUIREMENTS Outfall 001 Description of outfall and wastewater treatment system:

Operator requirements: Based on-the treatment system described above, the PCA requires that the treatment system be classified as Group .he lc E f l Certification Board Rules require that a Grade operator be assigned to operate this facility. Inspections of the facility will be required on a daily basis. Information for this outfall is based on NPDES Permit Application: 2C dated.12/20/04 dated 12/20/2004 Waterbody Data from Wasteload Allocation dated 4-1-2003 Receiving Waterbody: cfs MGD 7Q10 or other critical flow condition at discharge point (QQto) Average Annual Flow or other critical flow condition at discharge point (AAFd) Is the discharge above a drinking water intake? Yes, Intake #S46101, City of Rock Hill, Lake Wylie Source Water Protection Waterbody Flow Data cfs MGD 7QlOor other critical flow condition at source water protection area boundary (QQ,3) Average Annual Flow or other critical flow condition at source water protection area boundary (AAF) Dilution Factors (using formulas in Section C.2.a): DF, DF2 DF,, if applicable I DF4, if applicable I TSS Values for metals calculations: Effluent TSS concentration (TSS,) (mg/I) (based on monthly average value) Background or In-stream TSS concentration (TSSb) (mg/l) (Default is I mg/I) 1.0 Calculated In-stream Average TSS concentration after mixing (TSS,,) (mg/I) Appendix I contains the calculations for the water quality-based permit limitations and reasonable potential determinations. A. Proiect

Description:

The Duke Energy Corporation, Catawba Nuclear Station (hereinafter referred to as the Permittee) operates a nuclear powered steam electric generating facility with two nuclear units. The plant has a total rated electric generating capacity of 1129 megawatts (MWe) per unit per day. The facility is located on SC Highway 274 in Newport, South

Rationale Page 23 of 47 Permit No. SC0004278 Carolina. The effluent discharge from this facility is subject to the Steam Electric Power Generating Point Source Category 40 CFR Part 423. The receiving water is Lake Wylie which is a Freshwater water body by (Regulation 61-69)..A Freshwater is designated as freshwater suitable for primary contact recreation, secondary contact recreation, and as a source for drinking water after conventional treatment. The waters are suitable for fishing, and the survival and propagation of 2 balanced aquatic community, of fauna and flora, and for industrial and agricultural uses. B. General Information:

1. Facility contact and mailing address follow:

Cheryl Peed, EHS Manager Duke Energy Corporation/Catawba Nuclear Station 4800 Concord Road - York, South Carolina 29745

2. Permitting Regulations and Guidance:

1) Steam Electric Effluent Guidelines 40 CFR Part 423

.2) NPDES Permits Regulation 61-9, State Register, June 28, 1996

3) Water Classification and Standards (Regulation 61-68): Classified Waters (Regulations 61-69). State of South Carolina, June 26, 1998

4) Guidance for NPDES Permits Issued to Steam Electric Power Plants, Rebecca W. Hanmer, Office of Water Enforcement and Permits, USEPA, August 22, 1985..

3. Discharge:

ToLake Wylie

1) 7Q10 Flow

= 0 cfs; 0 MGD

2) Annual Average Flow = 0 cfs; 0 MGD

3) Lake Wylie is a Freshwater (Reg.61-69)

4) Dilution factor (DF) = Stream flow + Facility Discharge =

Facility Discharge WQ Aquatic Life DF1 = 1.0 WQ Human Health DF2= 1.-0

5) Instream Waste Concentration (IWC)

= 100%

4. Flows:

Total flow from the facility is 85.865 MGD, which is the sum of the following:

1) 001 (Low pressure service water (42.171 MGD), nuclear service water (20.136 MGD), cooling tower blowdown (11.04 MGD of wastewater discharged via internal Outfall 005) and liquid radiological waste (0.02 MGD of wastewater treated and discharged via internal Outfall 004)) = 73.367 MGD.

2) 002 (0.46 MGD of wastewaters from the service building sump, turbine building surnps, diesel generator catchment sump, sulfuric acid tank containment drainage sump, yard drain secondary containment sumps, motor pool car wash water, rainwater from valve pit sumps, and transformer sumps. 0.3 MGD of metal cleaning wastewaters are also treated at this outfall. Liquid radiological wastes (0.02 MGD of wastewaters treated and discharged via internal Outfall 004) also may be discharged throughbOutfall 002 but typically this discharge is via Outfall 001. The Permittee also included cooling tower blowdown (currently discharged via Outfall 001) in it's description of Outfall 002. However, during discussions with the Permittee during permit development it was

__L -II Rationale Page 24 of 47 Permit No. SC0004278 revealed that cooling tower blowdown is not currently and has never been discharged via Outfall 002, but the Permittee would like to reserve the right to discharge in such a marner, should the need arise) = 1.41 MGD

3) 003 (Sanitary sewerage) = 0.028 MGD

4) 004 (Internal) Liquid Radiological Waste through Outfall 001 = 0.02 MGD

5) 005 (Internal) Cooling Tower Blowdown through Outfall 001 = 11.04 MGD Outfall 001 Description of Discharge: Outfall 001 consists of low pressure service water (42.171 MGD), nuclear service water (20.136 MGD), cooling tower blowdown (11.04 MGD discharged via internal Outfall 005) and liquid radiological waste (0.02 MGD of wastewaters treated and discharged via internal Outfall 004). The sum of these waste streams, 73.367 MGD, is discharged to the receiving stream with no treatment. Descriptions of these discharges are as follows:

Cooling Tower Blowdown: See Outfall 005 for a description. Low Pressure Service Water: The low pressure service water is once-through, non-contact cooling water. Nuclear Service Water: The nuclear service water is once-through non-contact cooling water. Liquid Radiological waste: Liquid radiological wastes are treated at internal Outfall 004. See Outfall 004 for a description. RN pump bearing cleaning wastes: The nuclear service water pumps are cleaned annually to remove silt and deposits that restrict water flow. The monitoring and reporting of pH for Outfall 001 satisfies the concerns for this waste stream. Applicable effluent guidelines for this facility are the Steam Electric Point Source Category for existing sources, which provide the following limitations:

1. There shall be no discharge of PCBs.

2. Once-through cooling water shall have the following limitations:

Parameter Maximum concentration (mg/I) Total Residual Chlorine 0.20

3. Neither free available nor total residual chlorine may be discharged from any single generating unit for more than two hours per day and not more than one unit in any plant may discharge free available or total residual chlorine simultaneously unless the discharger demonstrates to the permitting authority that discharge for more than two hours is required for macro invertebrate control.

A. Flow

1. Form 2C Value:(3-21-00) 365 samples

= 62.6 MGD long term average value = 93.6 MGD maximum 30 day value = 93.58 MGD maximum daily value

Rationale Page 25 of 47 'Permit-No. SC0004278

2. Previous Permit: Monitor and Report 3.

Conclusion:

As in the previous permit, the flow shall be monitored and reported by 'a continuous flow measurement device. B. Temperature

1. Form 2C Value: (3/21/00)

=18° C (64.4 0F) long term average value (Winter) 181 samples = 30.51C (86.91F) maximum 30 day value (Winter) =24.70C,(76.46 0F) maximumdailyvalue (Winter) = 29.5CC (85.10F) long'term average value (Summer) 184 samples = 35.10C (95.180F) maximum 30 day value (Summer) - = 35.10C (95.18 0F) maximum daily value (Summer)

2. Previous Permit: 5.60 C (I 0.00F) (Apr-Sep) temperature rise above ambient; 7.80C (14.0 0F) (Oct-Mar) temperature rise above ambient

3. Water Classifications and Standards (Reg. 61-69): The receiving water temperature may not be increased by more than 57F(2.80C) above natural conditions or exceed a-maximum of 900 F(32.21C) unless a mixing zone has been established or a Section 316(a) determination under the Federal Clean Water Act has been completed.

4.

Conclusion:

On September 15, 1988, a Section 316(a) report was submitted in support of a 316(a) thermal variance request. Subsequently, correspondence dated July 1, 1992, from the permittee to SCDHEC proposed a delta T of 10F from April through August, and a delta T of 149F from September through March. After.a review of this request, our Office agreed with the following limits: Monthly Average Temperature Rise above ambient (April - September) '5f6°C(10.00 F) Temperature Rise above ambient (October - March) 7.81C(l 4.00F) Required monitoring shall be continuous by recorder, as in the previous permit. C. pH Limitations

1. Form 2C Value:(3-21-00) 52 samples

= 7.0 s.u. minimum, 8.3 s.u. maximum maximum daily-value

2. Previous Permit: 6.0 s.u. minimum, 9.0 s.u. maximum I

3. Water Classifications and Standards (Reg.61-68): The pH of the receiving waters shall be maintained between 6.0 standard units and 8.5 standard units.

4.

Conclusion:

Due to the Water Classifications and Standards (Reg.61-68), the permit shall monitor and report pH once per week by grab sample. D. Total Residual Chlorine (TRC)

1. Form 2C Value: (3-21-00) 50 samples

= 0 mg/I long term average value = 0 mg/l maximum 30 day value = 0 mg/l maximum daily value

2. Previous Permit: Monthly Average 0.011 mgA; Daily Maximum 0.019 mg/I

3. Effluent Guidelines: (0.2 mg/l)(73.6 MGD)/(82.14 MGD) = 0.18'mg/I.

4. Wasteload Allocation: Monthly Average 0.011 mg/I; Daily Maximum 0.019 mg/I

5. Water Quality Criteria Allowable Effluent Concentration:

Aquatic Life Criteria from Reg.61-68 (50 FR 30784, July 29, 1985): Monthly Average = 0.011 mg/ X DF, = 0.011 mg/ Daily Maximum =0.019 mg/IX DF1 =0.019 mg/l

6. Detection Limit: 0.05 mg/'

7.

Conclusion:

Since chlorine and sodium bromide are used in the cooling tower discharge, Total Residual Chlorine shall be limited to a monthly average of 0.011 mg/I and 'a -daily maximum of 0.019 mg/I, which is based on the

U Rationale Page 26 of 47 Permit No. SC0004278 Water Classifications and Standards (Reg. 61-68) and effluent guidelines values for Total Residual Chlorine at a frequency of cnce per week. E. Nitrite (NO,)

1. Form 2C Value: 0.55 mg/l maximum daily value (3-21-00)

2. Previous Permit:

Daily Maximum: 4.3 mg/l

3. Past DMR Data (12/97-1/00):

1.3 mg/l

4. Water Quality Criteria: No Observed Effect Concentration = 4.3 mg/l

5. Drinking Water Standard (MCL): 1,000 ug/l 6.

Conclusion:

Based on the NOEC, Nitrite (NO2 ) shall be limited to a daily maximum of 4.3 mg/l at a frequency of once per occurrence as noted in our 11-22-93 letter. F. Cadmium, total

1. Form 2C Value: <0.5 ug/h maximum daily value (3-21-00)

2. Previous Permit: Not regulated

3. Water Quality Criteria Allowable Effluent Concentration:

Aquatic Life Criteria from Reg.61-68 (57 FR 60848, Dec. 22, 1992): Monthly Average = 0.66 ug/l X DF, = 0.66 ug/l Daily Maximum = 1.32 ug/l X DF, = 1.32 ug/i

4. Human Health Consideration: 0.005 mg/l X DF2 = 0.005 ug/l

5. Detection Limit: 0.01 mg/I 6.

Conclusion:

Due to the levels indicated on the 2C Form, there will be no limit for Cadmium as in the previous permit. G. Chromium, total

1. Form 2C Value: <1.0 ug/l maximum daily value (3-21-00)

= 1.0 ug/lX6.2=6.2 ug/I

2. Previous Permit: A statement prohibiting the use of chromium based maintenance chemicals in the cooling towers was placed on the permit.

3. Effluent Guidelincs: 0.2 mg/I monthly average; 0.2 mg/i daily max.

4. Water Quality Criteria Allowable Effluent Concentration:

Aquatic Life Criteria from Reg.61-68 (57 FR 60848, Dec. 22, 1992): Monthly Average = 11.0 ugAI X DF, = 11.0,ug/i Daily Maximum = 16.0 ughl X DF, = 16.0 ughl

5. Human Health Consideration: 50 ug/l X DF2 = 50 ug/A

6. Detection Limit: 0.01 mg/l

7.

== Conclusion:== As in the previous permit, a statement prohibiting the use of chromium based maintenance chemicals in the cooling towers has been placed in the permit, and due to reasonable potential procedures, there will be no limit for Chromium. H. Copper, total

1. Form 2C Value: 0.01 mg/I maximum daily value (3-21-00)

= 10ug/1X6.2=62ugA

2. Previous Permit: Not regulated

3. Water Quality Criteria Allowable Effluent Concentration:

a. Aquatic Life Criteria from Reg.61-68 (57 FR 60848, Dec. 22, 1992):

Monthly Average = 6.5 ug/ X DF1 = 6.5 ug/l Daily Maximum = 9.2 ug/l X DF1 = 9.2 ug/l

b. Organoleptic data:

= Monthly Average: 1.0 mg/I; = Daily Maximum: 2.0 mg/I

Rationale Page 27 of 47 Permit No. SC0004278

4. Detection Limit: 0.01 mg/i 5.

Conclusion:

Using OReasonable PotentialO Procedures as given in Chapter 3 of the US EPA publication Technical Support Document for Water Quality-based Toxics Control (dated March 1991) of the 2C :Form sample results, total copper will be monitored and reported once per month for a period of 2 years, then these sample results will be evaluated to determine if a limit for total copper is needed. Also, any site specific study(s) conducted during the 2 year period (e.g. Water Effect Ratio, Chemical Translator, Mixing Zone Biotic Ligand Model, etc.) will be considered. See Part HI Special Condition No. 23. I. Lead. total

1. Form 2C Value: <2 ug/lImaximum daily value (3-21-00)

2. Previous Permit: Not regulated

3. Water Quality Criteria Allowable Effluent Concentration:

Aquatic Life Criteria from Reg.61-68 (57 FR 60848, Dec. 22, 1992): Monthly Average = 1.3 ug/l X DF, = 1.3 ugfl Daily Maximum = 2.6 ug/l X DF1 = 2.6 ug/l

4. Human Health Consideration: 50 ug/l X DF2 = 50.0 ugl

5. Detection Limit: 50.0 ugl-6.

Conclusion:

Due to the levels indicated on the 2C Form, there will be no limit for Lead as in the previous permit. J. Nickel total

1. Form 2C Value: <2ug/lmaximum daily value (3-21-00)

2. Previous Permit: Not regulated

3. Water Quality Criteria Allowable Effluent Concentration:

Aquatic Life Criteria from Reg.61-68 (57 FR 60848, Dec. 22, 1992): Monthly Average 88.0 ug/l X DF, = 88.0 ug/l Daily Average = 176.0 ugh X DF, = 176.0 ug/l

4. Human Health Consideration:

4,600 ug/] X DF2 = 4,600 ugh

5. Drinking Water Standard (MCL): 100 ugll

6. Detection Limit: 20.0 ugh 7.

Conclusion:

Due to the levels indicated on'the 2C Form, there will be no limit for Nickel as in the previous permit. K. Selenium, total

1. Form 2C Value: <2ug/lmaximum daily value (3-21-00)

2. Previous Permit: Not regulated

3. Water Quality Criteria Allowable Instream Concentration:

Aquatic Life Criteria from Reg.61-68 (57 FR 60848, Dec. 22,1992): Monthly Average = 5.0 ugh X DF, = 5.0 ugA-Daily Maximum = 10.0 ugI X DF, = 10.0 ug/l

4. Human Health Consideration: 50.0 ugh X DF2 = 50.0 ughl

5. Detection Limit: 5 ug-.

6.

Conclusion:

Due to the levels indicated on the 2C Form, there will be no limit for Selenium as in the previous permit. L. Zinc, total I. Form 2C Value: 0.005 mg/i maximum daily value (3-21-00) = 0.005 mg/l X 6.2 = 0.031 mg/I

2. Previous Permit: A statement prohibiting the use of zinc based maintenance chemicals in the cooling towers was placed on the permit.

3. Effluent Guidelines: 1.0 mg/l monthly average, 1.0 mg/I daily max.

4. Water Quality Criteria Allowable Effluent Concentration:

U Rationale Page 28 of 47 Permit No. SC0004278

a. Aquatic Life Criteria from Reg.61-68 (57 FR 60848, Dec. 22, 1992):

Monthly Average = 59 ug/l X DF1 = 59.0 ugh Daily Maximum = 65 ug/l X DF1 = 65.0 ug/l

b. Organoleptic data:

Monthly Average: = 5.0 mg/I Daily Maximum: =10.0 mg/I

5. Human Health Consideration: 5.0 mg/I X DF2 - 5.0 mg/I

6. Detection Limit: 0.01 mg/i 7.

Conclusion:

As in the previous permit, a statement prohibiting the use of zinc based maintenance chemicals in the cooling towers has been placed in the pe mit. M. Hydrazine

1. Form 2C Value: Not a Form 2C application parameter

2. Previous Permit: Not limited

3. ((8.34)(0.76 MGD)(0.43 mg/I))

= 2.73 lbs/day (2.73 lbs/day)/((82.5 MGD)(8.34)) = 0.004 mg/i

3. Detection Limit: 0.005 mg/I 4.

Conclusion:

Hydrazine may be discharged with liquid radiological wastes via Outfall 001 or 002, limitations for hydrazine were considered for both of these Outfalls. In the past permit, a limitation of 0.43 mg/I daily maximum was imposed at Outfall 002. Due to the large amount of dilution from the cooling water at Outfall 001, hydrazine will not be limited. N. Ethylene Glvcol

1. Form 2C Value: Not a Form 2C application parameter

2.

Previous Permit: Not regulated

3. (8.34)(0.76 MGD)(l 1.9 mg/I)

= 75.4 lbs/day (75.4 lbs/day)/((82.5 MGD)(8.34)) = 0.11 mg/I (8.34)(0.76 MGD)(23.8 mg/I) = 150 lbs/day (150 lbs/day)/((82.5 MGD)(8.34)) = 0.22 mg/I

4. Detection Limit: 0.005 mg/I 5.

Conclusion:

Ethylene Glycol may be discharged with radiological wastes via Outfall 001 or 002, ethylene glycol limitations were considered for both these Outfalls. Due to the large amount of dilution from the cooling water at Outfall 001, ethylene glycol will not be limited.

0. Boron, total

1. Form 2C Value:0.17 mg/I maximum daily value (3-21-00)

= 0.17 mg/I X 6.2 = 1.054 mg/I

2. Previous Permit: Not regulated

3. Past DMR Data (8/84-8/90): = <0.2 mg/I Avg.; 0.58 mg/I Daily Max.

4. Drinking Water MCL (Maximum Contaminant Level)

-from Water Quality Criteria, Second Edition, McKee & Wolf, California State Water Resources Control Board, Publication 3-A, Jan. 1963: monthly average: 20 mg/I daily maximum: 40 mg/I

5. Detection Limit: 0.02 mg/I 6.

Conclusion:

Using OReasonable Potential ProceduresO and due to the past sampling data for Boron, there will be no limit for Boron as in the previous permit. Outfall 002 Outfall 002 consists of wastewater from sources including the service building sump, turbine building sumps, diesel

Rationale Page 29 of 47 Permit No. SC0004278 generator catchment sump, sulfuric acid tank containment drainage sump, yard drain secondary; containment sumps, rainwater from valve pit sumnps, transformer sumps, and metal cleaning wastes (0.3,MGD/occurrence). The sum of these waste streams, 1.41 MGD, is discharged to the receiving water after treatment in the conventional wastewater treatment system, which incorporates sedimentation, skimming, precipitation, co-precipitation, neutralization, chemical oxidation, and mixing. Liquid radiological wastes (0.02 MGD of wastewaters treated and discharged via internal Outfall 004) also may be potentially discharged through Outfall 002 but typically discharges via Outfall 001.' The Permittee also included cooling tower blowdown (currently discharged via Outfall 001) in its description of Outfall 002. However, during discussions with the Permittee during the permit development process it was revealed that cooling tower blowdown is not currently discharged via Outfall 002, but the Permittee would like to reserve the right to discharge in such a manner, should the need arise (i.e., chlorine from the cooling tower at high levels). Therefore,' two sets of limitations are derived based on the current and the possible situations. Applicable effluent guidelines for this facility are the Steam Electric Point Source Category for existing sources, which provide the following limitations: I. The pH of all discharges, except once-through cooling water shall be within the range of 6.0 standard units to 9.0 standard units..

2. There shall be no discharge of PCBs.

3.

Low volume wastes Parameter Maximum for any Average of daily values I day (mg/l) for 30 consecutive days shall not exceed (mg/I) Total Suspended Solids 100.0 30.0 Oil and Grease 20.0 I 5.0 Metal cleaning wastes shall have the following limitations: Parameter Maximum for any Average of daily values. 4. I day (mg/I) shall not exceed for 30 consecutive days2 (mg/I) Total Suspended Solids' 100.0 30.0 Oil and Grease 20.0 15.0 Copper, total '.0 1.0 Iron, total 1.0 1.0 I..; A. Flow

1. Form 2C Value:(3-21-00) 94 samples

= 1.47 MGD long term average value = 2.12 MGD maximum daily value 'For purposes of this permit, 30 day average and monthly average shall be deemed as equivalent. 2 For purposes of this permit, 30 day average and monthly average shall be deemed as equivalent.

Rationale Page 30 of 47 Permit No. SC0004278

2. Previous Permit: Monitor ard Report

3. Wasteload Allocation:

A flow limit of 1.29 MGD. 4.

Conclusion:

Monitoring requirements of once per week by flow indicator, as in the previous permit, are adopted. B. Total Residual Chlorine (TRC)

1. Form 2C Value:(3-21-00) 8 samples

= 0 mg/i long term average value = 0 mg/i maximum daily value

2. Previous Permit:

Monthly Average 0.011 mg/I; Daily Maximum 0.0 19 mg/I

3. Wasteload Allocation: Monthly Average 0.011 mg/i; Daily Maximum 0.019 mg/I

4. Water Quality Criteria Allowable Effluent Concentration:

Aquatic Life Criteria from Reg.61-68 (50 FR 30784, July 29, 1985): Monthly Average 0.011 mg/I Daily Maximum 0.019 mg/i

5. Detection Limit: 0.05 mg/i 6.

Conclusion:

Chlorine is present through its use as hypochlorite during treatment and by its presence in chemicals contained in the low volume wastes. Total Residual Chlorine will be limited by Water Classifications and Standards (Reg. 61-68) to a monthly average of 0.011 mg/i and a daily maximum of 0.019 mg/l. Monitoring will be conducted once per day over a two day period after treatment by grab sample. C. 5-day Biochemical Oxvyen Demand (BOD5) I. Form 2C Value: (3-21-00) 13 samples = 3.9 mg/I; 47.8 lbs/day long term average value = 6.2 mg/I; 109.7 lbs/day maximum daily value

2. Previous Permit: Monitor and Report

3. Wasteload Allocation: Monitor and Report

4. Detection Limit: <2 mg/i 5.

Conclusion:

Due to the possibility that the expected differing physical characteristics of the two water bodies may inhibit mixing, thus trapping pollutants in the small cove, The permittee will be required monitor and report for BOD5 once per month The monitoring shall be conducted once per month by grab sample type. D. pH Limitations

1. Form 2C Value: (3-21-00) 37 samples 6.1 minimum, 8.5 maximum maximum daily value

2. Previous Permit: 6.0 minimum, 9.0 maximum

3. Effluent Guidelines: 6.0 minimum, 9.0 maximum

4. Water Classifications and Standards (Reg.61-68): The pH of the receiving waters shall be maintained between 6.0 standard units standard units and 8.5 standard units.

5.

Conclusion:

As in the previous permit, pH shall be limited to a minimum of 6.0 standard units to a maximum of 9.0 standards units. Monitoring requirements shall be once per week by grab sample. E. Oil and Grease

1. Form 2C Value: (3-21-00) 24 samples

= I mg/I long term average value = 2.7 mg/i maximum 30 day value = 2.7 mg/I maximum daily value

2. Previous Permit:

15 mg/l monthly average; 20 mg/I daily maximum

3. Effluent Guidelines: 15 mg/i monthly average; 20 mg/I daily maximum

4. Detection Limit: <5 mg/I 5.

Conclusion:

With the exception of motor pool car wash water, all discharges from Outfall 002 have oil and grease

Rationale Page 31 of 47 Permit No. SC0004278 limitations of 15 mg/l daily average and 20 mg/I daily maximum (i.e., low volume and metal cleaning wastes) as per the Steam Electric Effluent Guidelines. Since the motor pool car wash water provides dilution, it must be accounted for via the following3: 30 day Daily Flow Average Maximum Total low volume and metal cleaning wastes process flows 0.7592 MGD 15mg/ 20 mg/I Total non-contaminated flows - cooling tower blowdown 0.0 MGD 0 mg/ 3 mg/1 - carwash water 0.0008 MGD 15 mg/I 20 mg/I Total flows 0.76 MGD Using this data, the limitations at Outfall 001 are calculated as follows: Oil and Grease Monthly Average Limit 0.7592 (15) + 0.0 (0) + 0.0008 (IS) = 15 mg/l 0.76 Oil and Grease Daily Maximum Limit 0.7592 (20) + 0.0 (3) + 0.0008 (20) =20 mg/l 0.76 Monitoring requirements of once per month by grab sample, as in the previous permit. F. Total Suspended Solids (TSS)

1. Form 2C Value:(3-21-00) 24 samples

= 6.4 mg/l long term average value =17.4 mg/l maximum daily value

2. Previous Permit: 30 mg/I daily average, 1 00 mg/I daily maximum

3. Effluent Guidelines: 30 mg/I monthly average and 100 mg/] daily maximum

4. Detection Limit: <1 mg/I 5.

Conclusion:

With the exception of motor pool car wash water, all discharges from Outfall 002 have TSS limitations of 30 mg/l daily average and 100 mg/I daily maximuim (i.e., low volume and metal cleaning wastes) as per the Steam Electric Effluent Guidelines. Since the motor pool car wash water provides dilution, it must be accounted for via the following:

30day Dailyi Flow Average Maximum Total low volume and metal cleaning waste process flows 0.7592 MGD 30 mg/I 100 mg/l 3

The procedures and limitations for flow weighted averaging calculations when regulated waste streams are commingled are taken from the August 22, 1985, memo entitled Guidance for NPDES Permits Issued to Steam Electric Power Plants."

Rationale Page 32 of 47 Permit No. SC0004278 Total non-contaminated flows - cooling tower blowdown 0.0 MGD 30 mg/i 60 mg/i - car wash water 0.0008 MGD 30 mg/i 100 mg/I Total flows 0.76 MGD Using this data, the limitations at Outfall 001 are calculated as follows: TSS Monthly Average Limit 0.7592 (30) + 0.0 (30) + 0.0008 (30)= 30 mg/i 0.76 TSS Daily Maximum Limit 0.7592 (100) + 0.0 (60) + 0.0008 (100) = 100 mg/I 0.76 Monitoring requirements of once per month by grab sample, as in the previous permit. G. Cadmium, total

1. Form 2C value: <0.5 ugh maximum daily value (3-21-00)

2. Previous Permit: Not regulated

3. Water Quality Criteria Allowable Effluent Concentration:

Aquatic Life Criteria from Reg.61-68 (57 FR 60848, Dec. 22, 1992): Monthly Average = 0.66 ugA X DF, = 0.66 ug/h Daily Maximum = 1.32 ug/l X DF, = 1.32 ugh

4. Human Health Consideration: 0.01 mg/I X DF2 = 0.01 ugA

5. Detection Limit: 10.0 ug/I 6.

Conclusion:

Due to the levels indicated on the 2C Form, there will be no limit for Cadmium as in the previous permit. H. Copper. total I. Form 2C Value: 6 ug1 maximum daily value (3-21-00) 6 ug/ X 6.2 = 37.2 ug/1

2. Previous Permit: a monthly average and daily maximum of 0.0125 mg/I

3. Effluent Guidelines: 1.0 mg/I monthly average, 1.0 mg/i daily max.

4. Intake Background Levels (10-1-91): 0.006 mg/I

5. Water Quality Criteria Allowable Effluent Concentration:

a. Aquatic Life Criteria from Reg.61-68 (57 FR 60848, Dec. 22, 1992):

Monthly Average = 6.5 ugA X DF, = 6.5 ug/h Daily Maximum = 9.2 ug/I X DF, = 9.2 ugh

b. Organoleptic data:

= Monthly Average: 1.0 mg/I = Daily Maximum: 2.0 mg/l

6. Detection Limit: 0.01 mgA 7.

Conclusion:

With the exception of metal cleaning wastes, the sources of discharge at this outfall (0.7592 MGD of low volume wastes and 0.0008 MGD of car pool wash water) are not regulated for copper. Therefore, at the point of discharge from Outfall 002, the copper limit (both monthly average and daily maximum), after flow weighted averaging to account for dilution, would be: (1.0 mg/1)(0.3 MGD)/(0.76 MGD) = 0.395 mg/l Due to no dilution being provided by the receiving waters, the effluent limit for Outfall 002 based on water quality

Rationale 'Page 33 of 47 Permit No. SC0004278 criteria is 0.0065 mg/l maximum, which is more stringent than the limit based on effluent guidelines. Therefore, the water quality based limit of 0.0065 mg/i daily maximum is' adopted.' A monthly average limitation is not adopted since the daily maximum is more stringent than what the monthly average would be. With the addition of the intake background level of 0.006 mg/I, a limit of 0.0125 mg/i is established. Monitoring requirements of once per metal cleaning occurrence are adopted. Monitoring requirements are based on both the:possibility of exceedence of these limitations (the application indicates <0.03 mg/l at the discharge-from Outfall 002) and the potential that the highest concentrations of copper will be evident 'during metal cleaning'waste treatment.

1. Chromium, total

1. Form 2C Value: <I ug/Imaximum daily value (3-21-00)'

2. Previous Pernit: Not regulated

3. Effluent Guidelines: 0.2 mg/i monthly average; 0.2 mg/I daily max.

4. Water Quality Criteria Allowable Effluent Concentration:

Aquatic Life Criteria from Reg.61-68 (57 FR 60848, Dec.22, 1992): Monthly Average = 1.0 ug/I X DF, = 1.0 ug/l DailyMaximum 16.0 ug/l X DF, =16.0 ug'

5. Human Health Consideration: 50 ug/I X DF2 50 ug/l

6. Detection Limit: 0.01 mg/I 7.

Conclusion:

Due to the levels indicated on the 2C Form, there will be no limit for Chromium as in the previous permit. J. Iron, total

1. Form 2C Value: 0.15 mg/I maximum daily value (3-21-00)

2. Previous Permit: a monthly average and daily maximum of 0.645 mg/I

3. Effluent Guidelines: 1.0 mg/I monthly average, 1.0 mg/I daily max.

4. Intake Background levels: 0.48 mg/I (3-27-97)

5. Detection Limit: 0.001 mg/I 6.

Conclusion:

With the exception of metal cleaning wastes, the sources of discharge at this outfall (0.7592 MGD of low volume wastes and 0.0008 MGD of car pool wash water) are not regulated for iron. Therefore, at the point of discharge from Outfall 002, the iron limit (both monthly average and daily maximum), after flow weighted averaging to account for dilution, would be: (1.0 mg/1)(0.3 MGD)/(0.76 MGD) =0.395 mg/I Therefore, with the addition of the intake background level of 0.48 mg/I, a limit of 0.875 mg/I daily maximum and monthly average are adopted at the discharge point from Outfall 002.: Monitoringxrequirements of once per metal cleaning occurrence by grab sampleare adopted based on the previous monitoring requirements at Outfall 005. K. Lead, total

1. Form 2C value: 2.6 ug/Imaximum daily value (3-21-00) -

2. Previous Pernit: Not regulated X

3. Water Quality Criteria Allowable Effluent Concentration:

Aquatic Life Criteria from Reg.61 -68 (57 FR 60848, Dec. 22, 1992): Monthly Average 1.3 ug/A X DF, 1.3 ug Daily Maximum =2.6 ug/l X DF =2.6 ig/l-

4. Human Health Consideration: 50 ug/I X DF2 = 50.0 ug/l.

5. Detection Limit: 50.0 ug/I 6.

Conclusion:

Due to the levels indicated on the 2C Form, there will be no limit for Lead as in the previous permit. L. Nickel. total

1. Form 2C value: <2 ug/I maximum daily value (3-21-00)

2. Previous Permit: Not regulated

3. Water Quality Criteria Allowable Effluent Concentration:

Rationale Page 34 of 47 Permit No. SC0004278 Aquatic Life Criteria from Reg.61-68 (57 FR 60848, Dec. 22, 1992): Monthly Average = 88.0 ugh X DF1 = 88.0 ug/l Daily Average= 176.0 ug/l X DF1 = 176.0 ugh

4. Human Health Consideration: 4,600 ug/h X DF2 = 4,600 ug/h

5. Drinking Water Standard (MCL): 100 ugh

6. Detection Limit: 20.0 ug/l 7.

Conclusion:

Due to the levels indicated on the 2C Form, there will be no limit for Nickel as in the previous permit. M. Selenium. total

1. Form 2C value: <2 ug/ maximum daily value (3-21-00)

2. Previous Permit: Not regulated

3. Water Quality Criteria Allowable Instream Concentration:

Aquatic Life Criteria from Reg.61-68 (57 FR 60848, Dec. 22, 1992): Monthly Average = 5.0 ug/l X DF1 = 5.0 ugh Daily Maximum = 10.0 ug/l X DF1 = 10.0 ugh

4. Human Health Consideration: 50.0 ug/l X DF2 = 50.0 ug/l

5. Detection Limit: 0.005 mg/i 6.

Conclusion:

Due to the levels indicated on the 2C Form, there will be no limit for Selenium as in the previous permit. N. Zinc, total I. Form 2C Value: 0.04 mgil maximum daily value (3-21 -00) 0.04 mg/I X 6.2 = 0.248 mg/i

2. Previous Permit: Not regulated

3. Effluent Guidelines: 1.0 mg/I monthly average, 1.0 mg/i daily max.

4. Water Quality Criteria Allowable Effluent Concentration:

a. Aquatic Life Criteria from Reg.61-68 (57 FR 60848, Dec. 22, 1992):

Monthly Average = 59 ugAI X DF, = 59.0 ug/l Daily Maximum = 65 ug/I X DF, = 65.0 ugA

b. Organoleptic data: = Monthly Average:

= 5.0 mg/I = Daily Maximum: =10.0 mg/i

5. Human Health Consideration: 5.0 mg/i maximum human health standard

6. Detection Limit: 0.01 mg/I 7.

Conclusion:

Due to the levels indicated on the 2C Form, there will be no limit for Zinc as in the previous permit.

0. Hydrazine

1. Form 2C Value: Not a Form 2C application parameter

2. Previous Permit: 0.43 mg/I daily maximum

3. Water Quality Criteria: 0.077 mg/I (Ceriodaphnia dubia) chronic toxicity value

4. Detection Limit: 0.005 mg/I 5.

Conclusion:

Hydrazine originates from both low volume wastes and from internal Outfall 004 and is therefore limited at this outfall. Due to Water Quality Criteria, Hydrazine shall be limited to a daily maximum of 0.077 mg/I. Monitoring requirements of once per occurrence by grab sample, as in the previous permit, are adopted. P. Nitrite (NO,)

1. Form 2C value: I mgA (03-21-00)

2. Previous Permit: Not regulated

3. Water Quality Criteria: No Observed Effect Concentration = 4.3 mg/I

4. Drinking Water Standard (MCL): 1000 ugA 5.

Conclusion:

Due to the NOEC, Nitrite (NO2 ) shall be limited to a daily maximum of 4.3 mg/I at a frequency of

Rationale Page 35 of 47 Permit No. SC0004278 once per occurrence by grab sample as discussed in out 11-22-93 letter. Q. Ethylene Glycol

1. Form 2C Value: Not a Form 2C application parameter

2. Previous Permit: 11.9 mg/l daily average, 23.8 mg/ daily maximum

3. Past DMR Data (9/89-8/90): 4.5 mg/i daily avg., 10 mg/l daily max.

4. Detection Limit: <0.00 1 mg/I 5.

Conclusion:

Ethylene glycol originates from both low volume wastes and from internal Outfall 004. Since the past sampling data for Ethylene Glycol indicates there has been no significant impact to the water quality, there will be no limit for Ethylene Glycol. Outfall 003 i-Description of Discharge: Outfall 003 consists of 0.028 MGD of sanitary sewerage-and motor pool car wash water treated via grit removal, screening, comminution, aerated lagoons, stabilization and sedimentation, and chlorination. A. Flow

1. Form 2E Value: (3-21-00) 365 samples

= 0.0202 MGD average daily value = 0.0832 MGD maximum daily value

2. Previous Permit: Monitor and report

3. Wasteload Allocation:

A flow limit of 0.035 MGD. 4.

Conclusion:

Monitoring requirements of once per month by flow indicator, as in the previous permit, are adopted. B. Total Residual Chlorine (TRC) I. Form 2E Value: (3-21-00) 48 samples = z0.05 mg/l average daily value = <0.05 mg/I maximum daily value

2. Previous Permit: Notregulated

3. Water Quality Criteria Allowable Effluent Concentration:

Aquatic Life Criteria from Reg.61-68 (50 FR 30784, July 29, 1985):. Monthly Average 0.011 mg/I; Daily Maximum 0.019 mg/I

4. Detection Limit: 0.05 mg/I 5.

Conclusion:

Due to the large amount of mixing with the non-contact cooling water from Outfall 001, the permit will be limited to a monthly average of 0.5 mgA and. a daily maximum of 1.0 mg/I for Total Residual Chlorine. Monitoring shall be conducted once per week by grab sample. C. pHLimitations

1. Form 2E Value: (3-21-00) 53 samples

= 6.6 s.u. minimum, 7.2 s.u. maximum average daily value = 6.4 s.u. minimum, 7.8 s.u. maximum maximum daily value

2. Previous Permit: 6.0 minimum, 9.0 maximum

3. Water Classifications and Standards (Reg.61-68): The pH of the receiving waters shall be maintained between 6.0 standard units standard units and 8.5 standard units.

4.

Conclusion:

As in the previous permit, limits of 6.0 standard units minimum and 9.0 standards units maximum are adopted. Monitoring requirements shall be once per week by grab sample D. 5-day Carbonaceous Biochemical Oxygen Demand (CBOD5) I. Form 2E Value: (3-21 -00) 16 samples = 4.8 mg/I; 0.8 lbs/day average daily value = 9.4 mg/I; 6.5 lbs/day -maximum daily value.

LI Rationale Page 36 of 47 Permit No. SC0004278

2. Previous Permit: 25 mg/I daily average, 50 mg/I daily maximum (CBOD5)

3. Wasteload Allocation: A monthly average BODs limit of 30.0 mg/l (secondary limits).

4. Detection Limit: <2 mgA/

5.

Conclusion:

As requested rather than limiting BOD5, Carbonaceous Biochemical Oxygen Demand (CBOD) will be limited using Regulation 61-9 Secondary limits for five (5) day CBOD with a monthly average of 25.0 mg/I and a daily maximum of 50.0 mg/I. The sample type shall be a 24 hour composite sample. E. Total Suspended Solids (TSS)

1. Form 2E Value: (3-21-00) 15 samples

= 8.7 mg/I; 1.5 Ibs/day average daily value = 20.3 mg/I; 14.1 Ibs/day maximum daily value

2. Previous Permit: 90 mg/i daily average, 135 mg/l daily maximum

3. Detection Limit: <1 mg/l 4.

Conclusion:

As in the previous permit, Total Suspended Solids shall be limited to a monthly average of 90 mg/l and a daily maximum of 135 mg/I. Monitoring requirements of once per month, are adopted. The sample type is a 24 hour composite sample. F. Fecal Coliform

1. Form 2E Value: (3-21 -00) 15 samples

= 29/100 ml average daily value = 170/100 ml maximum daily value

2. Previous Permit: 200/100 ml daily average, 4001100 ml daily maximum

3. Water Classifications and Standards (Reg.61-68): Not to exceed a geometric mean of 200/100 ml, based on a 5 consecutive samples during any 30 day period; nor shall more than 10% of the total samples during any 30 day period exceed 400/100 ml.

4. Detection Limit: <2/100 ml 5.

Conclusion:

Due to the S.C. Water Classifications and Standards (Reg. 61-68), Fecal Coliform shall be limited to a monthly average of 200/100 ml and a daily maximum of 400/100 ml. Monitoring requirements of once per month by grab sample, as in the previous permit. G. Dissolved Oxygen

1. Form 2E Value: Not a Form 2E application parameter

2. Previous Permit: a minimum of 1.0 mg/I

3. Wasteload Allocation: A minimum of 1.0 mg/l

4. Water Classifications and Standards (Reg.61-68): Daily average not less than 5.0 mg/l with a low of 4.0 mg/I.

5.

Conclusion:

Using the Wasteload Allocation, Dissolved Oxygen shall be limited to a minimum of 1.0 mg/I. The monitoring frequency shall be once per month by grab sample. H. Phosphorous, total I. Form 2E Value: Not a Form 2E application parameter

2. Previous Permnit: Not regulated

3.

Wasteload Allocation: Monitor and Report Results 4.

Conclusion:

Using the Wasteload Allocation, Total Phosphorous shall be monitored and the results reported. The monitoring frequency shall be once per month by grab sample. Outfall 004 Description of Discharge: Outfall 004 consists of 0.007 MGD of liquid radiological waste treated via filtration, demineralization, mixing, oxidation, coagulation and chemical metal cleaning waste. Outfall 004 is ultimately discharged via either Outfall 001 or Outfall 002. Applicable effluent guidelines for this facility are the Steam Electric Point Source

Rationale Page 37 of 47 Permit No. SC0004278 Category for existing sources, which provide the following limitations:

1. Chemical Metal cleaning wastes shall have the following limitations:

Parameter Maximum for any Average of daily values day (mg/A) s efagex cseecymegoys Copper, total 1.0 1.0 Iron, total 1.0 1.0 A. Flow

1. Form2CValue: 0.02MGDmaximumdailyvalue (3-21-00)

2. Previous Permit: Monitor and Report 3.

Conclusion:

Monitoring requirements of once per occurrence of chemical metal cleaning by flow estimate sample type. B. Oil and Grease

1. Form 2C Value: <5 mg/I maximum daily value (3-21-00)

2. Previous Permit: Not regulated

3. Detection Limit: <5 mg/I 4.

Conclusion:

Due to the Part m Special Condition Item V. of the (3-26-84) permit and the levels detected in the past sampling, there will be no limit for Oil and Grease. C. Total Suspended Solids (TSS)

1. Form 2C Value: <5 mg/I maximum daily value

'(3-21 -00)

2. Previous Permit: Not regulated'

3. Detection Limit: <1 mg/I 4.

Conclusion:

Due to the Part III Special Condition Item V. of the (3-26-84) permit and the levels detected in the past sampling, there will be no limit for Total Suspended Solids. D. Copper. total

1. Form 2C Value: <0.005 mg/l maximum daily value - (3-21-00)'

2. Previous Permit:

1.0 mg/] monthly average, 1.0 mg/I daily max.'

3. Effluent Guidelines: 1.0 mg/l monthly average, 1.0 mg/i daily max.

4. Intake Background Levels (10-1-91)' 0.006'mg/l 5: Water Quality Criteria Allowable Effluent Concentration':

a. Aquatic Life Criteria from Reg.61-68 (57 FR 60848, Dec. 22, 1992): -

[; Monthly Average = 6.5 ug/l X DF, = 6.5 ug/l Daily Maximum = 9.2 ug/l X DF1 = 9.2 ug/'

b. Organoleptic data:

= Monthly Average:* l.Omg/I; Daily Maximum: 2.0 mg/I

6. Human Health Consideration: 1.0 mg/I maximum human health standard

7. Detection Limit: 0.01 mg/i 8..

Conclusion:

Due to the effluent guidelines, Copper will be limited to a monthly average and a daily maximum of 1.0 mg/I. Since this is a internal outfall, there will be no water quality based limit.', E. Iron, total

1. Form 2C Value: <0.05 mg/I maximum daily value (3-21 -00)

2. Previous Permit:

].0 mg/I monthly average, 1.0 mg/I daily max.

U Rationale Page 38 of 47 Permit No. SC0004278

3. Effluent Guidelines: 1.0 mg/l monthly average, 1.0 mg/l daily max.

4. Intake Background levels (10-1-91)<-OQ5 mg/i

5. Detection Limit: 0.001 mg/i 6.

Conclusion:

Due to the effluent guidelines, Iron will be limited to a monthly average and a daily maximum of 1.0 mg/I. Since this is a internal outfall, there will be no water quality based limit. F. Zinc, total

1. Form 2C Value: 0.008 mg/I maximum daily value (3-21 -00)

= 0.008 mg/l X 6.2 = 0.0496 mg/l

2. Previous Permit:

Not Regulated

3. Water Quality Criteria Allowable Effluent Concentration:

a. Aquatic Life Criteria from Reg.61-68 (57 FR 60848, Dec. 22,1992):

Monthly Average = 59 ug/l X DF, = 59.0 ug/l Daily Maximum = 65 ug/I X DF, = 65.0 ug/l

b. Organoleptic data:

= Monthly Average: = 5.0 mg/I = Daily Maximum: =10.0 mg/l

4. Human Health Consideration: 5.0 mg/I X DF2 = 5.0 mg/I

5. Detection Limit: 0.01 mg/I 6.

Conclusion:

Due to the levels indicated on the 2C Form and since this is a internal outfall, there will be no limit for Zinc. G. Hvdrazine

1. Form 2C Value: Not a Form 2C application parameter

2. Previous Permit: Not regulated

3. Water Quality Criteria: 0.077 mg/I Ceriodaphnia dubia chronic toxicity

3. Detection Limit: 0.005 mg/I 4.

Conclusion:

Since the Permittee may discharge liquid radiological wastes via Outfall 001 or 002, hydrazine limitations were considered for both of these Outfalls. In a previous permit, a limitation of 11.0 mg/I was imposed on this outfall. Due to the large amount of dilution from the cooling water at Outfall 001, hydrazine will not be limited. H. Ethylene Glycol

1. Form 2C Value: Not a Form 2C application parameter

2. Previous Permit: Not regulated

3. Past DMR Data (9/89-8/90): 210 mg/l daily avg., 210 mg/I daily max.

4. Detection Limit: <0.001 mg/I 5.

Conclusion:

Since the Permittee may discharge liquid radiological wastes via Outfall 001 or 002, ethylene glycol limitations were considered for both of these Outfalls. In a previous permit, limitations of 11.9 mg/l daily average and 23.8 mg/l daily maximum were imposed at Outfall 002. Due to the large amount of dilution from the cooling water at Outfall 001, ethylene glycol will not be limited.

1. Boron

1. Form 2C Value: 432 mg/l maximum daily value (3-21-00)

2. Previous Permit: Not regulated

3. Detection Limit: 0.02 mg/I 4.

Conclusion:

Due to the Part III Special Conditions Item U. of the (3-26-84) permit and the levels detected in the past sampling, there will be no limit for Boron.

Rationale Page 39 of 47 Permit No. SC0004278 Outfall 005 Cooling Tower Blowdown:There are a total of 6 cooling towers employed at the facility (3 cooling towers per nuclear unit). Cooling water in a closed cycle mechanical draft system cools the condensers to condense turbine exhaust-gas steam. Additives to the cooling tower include sulfuric acid, polyacrylate dispersant to enhance solids deposition, sodium hypochlorite, sodium bromide, sodium sulfite or sodium nitrite for dechlorination, and biocides.; Applicable effluent guidelines for this facility are the Steam Electric Point Source Category for existing sources, which provide the following limitations:

1. The pH of all discharges, except once-through cooling water shall be within the range of 6.0 standard units to 9.0 standard units.-

2. Cooling tower blowdown shall have the following limitations:

'I

_' I.' - Parameter concentration (mg/]) Average concentration (mg/]) - Free available chlorine 0.5 0.2

3. Cooling tower blowdown shall have the following limitations:

Parameter Maximum for any I day (mg/l) Average of daily values for 30 consecutive days4. shall not exceed (mg/i) The 126 priority no detectable no detectable pollutants, amount. amount except: Chromium, total 0.2 0.2 Zinc, total 1.0 1.0 .( A. Flow

1. FormK2CValue:(3-21-00) 47 samples

= 14.4 MGD long term average value = 14.4 MGD maximum daily average

2. Previous Permnit: Monitor and Report 3.

Conclusion:

Monitoring requirements of continuously by recorder, are adopted. B. pH

1. Form2CValue:(3-21-00) 48 samples 7.8 s.u. minimum, 8.6 s.u. maximum maximum daily value

2. Previous Permit: Not regulated

3. Effluent Guidelines: 6.0 minimum, 9.0 maximum

4. Water Classifications and Standards (Reg.61-68): The pH of the receiving waters shall be maintained between 6.0 For purposes of this permit, 30 day average and monthly average shall be deemed as equivalent.

Rationale Page 40 of 47 Permit No. SC0004278 standard units standard units and 8.5 standard units.

5.

== Conclusion:== Since this is an internal outfall, pH limitations are not adopted. PH will be monitored and reported at the outfall 001. C. Free Available Chlorine (FAC) or Oxidant (FAO)

1. Form 2C Value: Not provided

2. Previous Permit: FAC limited to monthly average 0.2 mg/l; daily maximum 0.5 mg/l

3. Effluent Guidelines: 0.2 mg/l monthly avg.; 0.5 mg/i daily max.

4. Detection Limit: 0.1 mg/l 5.

Conclusion:

The effluent guideline permit limits for Free Available Chlorine of 0.2 mg/l monthly average and 0.5 mg/I daily maximum are adopted. Monitoring requirements of once per week by multiple grab samples are adopted. D. Chromium. total I. Form 2C Value: Not provided

2. Previous Permit: Statement prohibiting the use of chromium based maintenance chemicals in the cooling towers.

3.

Effluent Guidelines: 0.2 mg/l monthly avg.; 0.2 mg/l daily max.

4. Water Quality Criteria Allowable Effluent Concentration:

Aquatic Life Criteria from Reg.61-68 (57 FR 60848, Dec. 22, 1992): Monthly Average = 11.0 ug/l X DF, = 11.0 ug/l Daily Maximum = 16.0 ug/l X DF, = 16.0 ug/1

5. Human Health Consideration: 50 ug/l X DF2 = 50 ug/l

6. Detection Limit: 0.01 mg/i 7.

Conclusion:

As in the previous permit, a statement prohibiting the use of chromium based maintenance chemicals in the cooling towers has been placed in the permit. E. Zinc, total I. Form 2C Value: Not provided

2. Previous Permit: Statement prohibiting the use of zinc based maintenance chemicals in the cooling towers.

3 Effluent Guidelines: 1.0 mg/I daily average, 1.0 mg/l daily maximum

4. Water Quality Criteria Allowable Effluent Concentration:

a. Aquatic Life Criteria from Reg.61-68 (57 FR 60848, Dec. 22, 1992):

Monthly Average = 59 ug/l X DF, = 59.0 ug/l Daily Maximum = 65 ug/l X DF, = 65.0 ug/l

b. Organoleptic data:

= Monthly Average: = 5.0 mg/l = Daily Maximum: =10.0 mg/l

5. Human Health Consideration: 5.0 mg/l maximum human health standard

6. Detection Limit: 0.01 mg/l 7.

Conclusion:

As in the previous permit, a statement prohibiting the use of zinc based maintenance chemicals in the cooling towers has been placed in the permit. F. Other Priority Pollutants

1. Form 2C Value: Not detected

2. Previous Permit: No detectable amount

3. Effluent Guidelines: No detectable amount monthly average, no detectable amount daily maximum as a result of cooling tower maintenance chemicals.

4. Water Quality Criteria: Varies

5. Human Health Consideration: Varies

6.

Detection Limit: Varies

7.

== Conclusion:== Previous permit limitations provided the Permittee with the option to either annually monitor for the

Rationale Page 41 of 47 Permit No. SC0004278 remaining priority pollutants or provide mass balance calculations to demonstrate that use of particular maintenance chemicals (as provided for in the permit application) will not result in detectable amounts of the toxic pollutants in the discharge. The previous permit limitations and monitoring requirements are adopted.,, Outfall 006 Description of Discharge: Outfall 006 is only used intermittently when the Standby Nuclear Service Water Pond is being used. The Standby Nuclear Service Water Pond is used as the ultimate heat sink in the case of a nuclear accident coincident with a loss of Lake Wylie. A polyacrylate solution will be added to the Nuclear Service Water, System to control silt deposition. A biocide (sodium hypobromite and/ or sodium hypochlorite) will also beadded to the system to control biofouling and under-deposit corrosion. Sodium bisulfite will be added to dcchlorinate'the system prior to discharge via Outfall 006. Heat exchanger wet-lay-up chemicals (biocide and Carbohydrazide, for oxygen could be discharged to this outfall but the occurrence/probability is low.

1. There shall be no discharge of PCBs.

2. Once-through cooling water shall have the following limitations:

Parameter _Maximum concentration (mg/i) Total Residual Chlorine 0.20

3. Neither free available nor total residual chlorine may be discharged from any single generating unit for more than two hours per day and not more than one unit in any plant may discharge free available or total residual chlorine simultaneously unless the discharger demonstrates to the permitting authority that discharge for more than two hours is required for macro invertebrate control.

A. Flow

1. Form 2E Value: (3/14/05)

= 27A MGD average daily value = 40.3 MGD maximum daily value 2.

Conclusion:

The flow shall be monitored and reported for the monthly average and the daily maximum per occurrence, but need not be more than once per week by estimate flow sample type. B. Temperature

1. Form 2E Value: (3/14/05)

= 570F average daily value (Winter) = 800F maximum daily value (Winter) = 790F average daily value (Summer) = 900F maximum daily value (Summer)

2. Water Classifications and Standards (Reg. 61-69): The receiving water temperature may not be increased by more than 50F(2.80C) above natural conditions or exceed a maximum of 900F(32.2'C) unless a mixing zone has been established or a Section 316(a) determination under the Federal Clean Water Act has been completed.'

3.

Conclusion:

The permittee shall monitor and report thetemperature of the intake and discharge for the monthly average and daily maximum and the delta T for the daily maximum for a period of one (1) year, then a report summarizing the sample results shall be submitted to the Department to be evaluated and to determine if a thermal limit is needed. See Part m Special Condition No. 24.

Rationale Page 42 of 47 Permit No. SC0004278 C. pH Limitations

1. Form 2E Value: (3/14/05)

= 6.0 s.u. minimum, 8.0 s.u. maximum

2. Water Classifications and Standards (Reg.61-68): The pH of the receiving waters shall be maintained between 6.0 standard units and 8.5 standard units.

3.

Conclusion:

Due to the Water Classifications and Standards (Reg.61-68), the pH shall be limited to 6.0 to 9.0 standard units at a frequency of once per occurrence, but need not be more than once per week by grab sample. D. Total Residual Chlorine (TRC I. Form 2E Value: (3/14/05) = 0 mg/l long term average value = 0 mg/l maximum daily value

2. Effluent Guidelines: = 0.2 mg/I

3. Water Quality Criteria Allowable Effluent Concentration:

Aquatic Life Criteria from Reg.61-68 (50 FR 30784, July 29, 1985): Monthly Average = 0.011 mg/I X DF1 = 0.011 mg/I Daily Maximum =0.019 mg/ X DF1 = 0.019 mg/I

4. Detection Limit: 0.05 mg/l 5.

Conclusion:

Since chlorine is used in the cooling tower discharges, Total Residual Chlorine shall be limited to a monthly average of 0.011 mg/I and a daily maximum of 0.019 mg/I, which is based on the Water Classifications and Standards (Reg. 61-68) and effluent guidelines values for Total Residual Chlorine at a frequency of once per occurrence, but need not be more than once week. Monitoring is not required when chlorine is not being used. IV. Chemical Additives A. Cooling Water Additives (Outfall 001 and Outfall 002, in some instances) Chlorine and Sodium Bromide additives -- Are regulated via Total Residual and Free Available Chlorine limits. Biocides -- Previously reported biocides are limited to the No Observable Effect Limitation (NOEL) concentration for general fish populations as a daily maximum. Dispersants -- Previously reported dispersants are limited to the NOEL concentration for general fish populations as a daily maximum. Corrosion Inhibitors -- Where not already limited in the permit, previously repcrted corrosion inhibitors are limited to the NOEL concentration for general fish populations as a daily maximum. B. Hazardous Materials (Outfalls 001, 002, and 004) Acidic and Basic Substances Since discharge outfalls have pH limitations, discharges of acids and bases previously reported will be regulated via the pH limitations. Chlorine Containing Substances Outfalls 001, 002, and 003 have chlorine containing substances that are either used during treatment or contained in the sources of the wastewater. Limitations for chlorine have been imposed at these Outfalls. V. Slud2e Disposal Sludge disposal at the Catawba site is in accordance with the Sludge Management Plan submitted 12/12/00 and in accordance with industrial waste landfill permit No. 463303-1601. The permittee shall obtain prior written approval for any sludge disposal activities at this facility.

Rationale Page 43 of 47 Permit No. SC0004278 VI. Onerator The Peznittei's present treatment system consists of grit removal, screening, cornminution, aerated lagoons, stabilization and sedimentation, and chlorination.' The highest classification of the operation of all treatment equipment is usually used to determine the operator requirement. Based on the sanitary treatment system classification, an operator with a Grade C-B or higher'.certification-is required to accept the responsibility of inspections made by lower grade operators. VII. Previous Biological Studies A. 316(a) Studies of the thermal effects of the discharge were provided in support of the 316(a) variance request. Additionally, the Permittee has also conducted dye studies to determine the dispersion characteristics of Outfall 001 and its dilution with the receiving water. B.316(b) In a March 17, 1987 letter, Duke Power Company provided information concerning the intake structures found in Lake Wylie and the Station's Standby Nuclear Service Water Pond. In a March 23, 1987.memorandum, it was determined that provided the screens are kept clean, the intake should not pose a significant threat to the biological integrity of Lake Wylie or the' Standby Nuclear Service Water Pond because of low water velocities.' As a result, a 316(b) study was not required to be performed. VIII. Groundwater Monitorine The Permittee shall monitor and report each of the four (4) groundwater monitoring wells semiannually for the following parameters: Water Level, tenth/feet Cadmium, total, mg/l Total Dissolved Solids Chromium, total, mg/l Total Organic Carbon Copper, total, mg/l pH (field), standard units Iron, total, mg/I Specific Conductance (field), umhos/cm Lead, total, mg/I Ammonia, (NH3) mg/I Manganese, total, mg/I Nitrate, (NO3) Mercury,,total, mg/I, Sulfate, mg/I Selenium, total, mg/I Arsenic, total, mg/I Silver, total, mg/I; Barium, total, mg/l Zinc, total, mg/I IX. Co-Treatment Commingling and co-treatment of discharges were taken into account at Outfall 001 which combines cooling tower blowdown,' once-through cooling wvater, liquid radiological wastes, and metal cleaning wastes. Commingling and co-treatment of discharges were taken into account at Outfall 002 which combines low volume wastewater, miscellaneous dilution water, and metal cleaning wastes. Where various wastes are combined for treatment and discharge, 40 CFR 423.15(n) requires that the quantity of each pollutant or pollutant property not exceed the specified limitation for that waste source. Applicable guideline concentrations were flow weighted in calculating final effluent concentrations. X. Toxicity Testing Since the chemical specific approach does not address all specific chemicals and their interactions with other components in the waste stream, a more comprehensive testing requirement is needed. To ensure that Water Quality Standards are not violated, whole effluent toxicity testing is being required at Outfalls 001 and 002. Testing will not be required for internal Outfalls or for the sanitary discharge Outfall 003.

U Rationale Page 44 of 47 Permit No. SC0004278 In accordance with policies set out in the South Carolina Department of Health and Environmental Control (SCDHEC) Bureau of Water Pollution Control Reasonable Potential Procedures for NPDES Pennits, Whole Effluent Toxicity (WET) testing is imposed on a discharge based on the reasonable potential of that discharge to cause or contribute to a water quality violation. The WET limits are determined based on the instream waste concentration (TWC) for aquatic life protection. The IWC is calculated as follows: Outfall 001 IWC = (Effluent flow/(7Q10 flow + Effluent flow)) X 100 = (85.865/(0 + 85.865)) X 100 = 100% Outfall 002 IWC = (Effluent flow/7Q10 flow + Effluent flow) X 100 IWC = 1.41/(0+ 1.41)X 100 IWC = 100% If a diffuser is not installed with an IWC of 100°, then chronic toxicity is required. An IWC of 100% corresponds to a chronic test concentration (CTC) of 100%vo since no mixing zone is present. The test shall be performed using Ceriodaphnia dubia as the test organism, unless approval for an alternate species is requested and granted by the Department. Toxicity testing limitations have been imposed in this permit as a chronic single dilution whole effluent toxicity (pass/fail test) as was in an earlier permit at a CTC of 100%. The toxicity testing monitoring frequency shall be once per quarter. The specific chronic toxicity language is included in Part m Special Condition No. 13 of the permit.

4. Water Quality Data: Effluent Limits for pH are established in Reg. 61-68.G. For Class Fresh Water this value is standard units.

Xl. PROCEDURES FOR REACHING A FINAL PERMIT DECISION A. Comment Period (R.61-9.124. 0 and I 1) The Department of Hcalth and Environmental Control proposes to issue an NPDES permit to this applicant subject to the effluent limitations and special conditions outlined in this document. These determinations are tentative. During the public comment period, any interested person may submit written comments on the draft permit to the following address: SC Dept. of Health and Environmental Control Industrial, Agricultural and Storm Water Permitting Division Bureau of Water 2600 Bull Street Columbia, South Carolina 29201

Rationale Page 45 of 47 Permit No. SC0004278 For additional information, interested persons may contact Timothy M. Eleazer at 803-898-3964. All written comments received during the period beginning November 5, 2003 and ending on December 5, 2003 shall be considered in making the final decision and shall be answered as prescribed below. See Public Notice

1. 15-24-R.

Per R.61-9.124.17, the Department is only required to issue a response to comments when a final permit is issued. This response shall:

1. Specify which provisions, if any, of the draft permit have been changed in the finalypermit decision, and the reasons for the change; and

2. Briefly describe and respond to all significant comments on the draft permit raised during the public co.mment period, or during any hearing.

The response to comments shall be available to the public. B. Public Hearings (R.61-9.124.1 I and 12) During the public comment period, any interested person may request a public hearing, if no hearing has already been scheduled. A request for a public hearing shall be in writing and shall state the nature'of the issues proposed to be raised in the hearing. Determinations and Scheduling.

1. Within the thirty (30) day comment period or other applicable comment period provided after posting or publishing of a'public notice, an applicant, any affected state or interstate agency, the Regional Administrator or any other interested person or agency may file a petition with the Department for a public hearing on an application for.a permit. A petition for a public hearing shall indicate the specific reasons why a hearing is requested, the existing or proposed discharge identified therein and specifically ifidicate" which portions of the application or other permit form or information constitutes necessity for a public hearing. If the Department determines that a petition constitutes significant cause or that there is sufficient public interest in an application for a public hearing, it may direct the scheduling of a hearing thereon.'

2. A hearing shall be scheduled not less than four (4) nor.more than eight (8) weeks after the Department determines the necessity of the hearing in the geographical location of the a'plicant or, at the discretion of the Department,' at another appropriatelocation, and shall be noticed at least thirty (30) days before the hearing.

The notice of public hearing shall be transmittedlto the applicant and shall be published in at least one (1) newspaper of general circulation in the geographical area of the existing or proposed discharge identified on the permit application and shall be mailed to any person or group upon request thereof. Notice shall be mailed to all persons and governmental agencies, which received a copy of the notice or the fact sheet for the permit application.

3. The Department may hold a single public hearing on related groups of permit applications.'

4. The Department may also hold a public hearing at its discretion, whenever, for instance, such a hearing might clarify one or more issues involved in the permit decision;

5. Public notice of the hearing shall be given in accordance with R.61-9.124.10.

Rationale Page 46 of 47 Permit No. SC0004278 Any person may submit oral or written statements and data concerning the draft permit. Reasonable limits may be set upon the time allowed for oral statements, and the submission of statements in writing may be required. The public comment period under R.61-9.124.10 shall automatically be extended to the close of any public hearing under this section. The hearing officer may also extend the comment period by so stating at the hearing. A tape recording or written transcript of the hearing shall be made available to the public. C. Obligation to raise issues and provide information during the public comment period. (R.61-9.124.13) All persons, including applicants, who believe any condition of a draft permit is inappropriate or that the Department's tentative decision to deny an application, terminate a permit, or prepare a draft permit is inappropriate, must raise all reasonably ascertainable issues and submit all reasonably available arguments supporting their position by the close of the public comment period (including any public hearing). No issue shall be raised during an appeal by any party that was not submitted to the administrative record as part of the preparation and comment on a draft permit, unless good cause is shown for the failure to submit it. Any supporting materials which are submitted shall be included in full and may not be incorporated by reference, unless they are already part of the administrative record in the same proceeding, or consist of State or Federal statutes and regulations, Department and EPA documents of general applicability, or other generally available reference materials. Commenters shall make supporting materials not already included in the administrative record available. (A comment period longer than 30 days may be necessary to give comnmenters a reasonable opportunity to comply with the requirements of this section. Additional time shall be granted under R.61-9.124.10 to the extent that a commenter who requests additional time demonstrates the need for such time). D. Issuance anrd Effective Date of the Permit I. After the close of the public comment period on a draft permit, the Department shall issue a final permit decision. The Department shall notify the applicant and each person who has submitted written comments or requested notice of the final permit decision. This notice shall include reference to the procedures for appealing a decision on a permit. For the purposes of this section, a final permit decision means a final decision to issue, deny, modify, revoke and reissue, or terminate a permit.

2. A final permit decision shall become effective 30 days after the service of notice of the decision unless:

(a) A later effective date is specified in the decision; or (b) No comments requested a change in the draft permit, in which case the permit shall become effective on the effective date shown in the issued permit.

3. Issuance or Denial of Permits. An appeal to a final determination of the Department or to a condition of a permit issued or the denial of a permit pursuant to the State law and this regulation shall be in accordance with and subject to 48-1-200 of the SC Code.

4. Unless specific circumstances warrant otherwise, the permit will become effective on the first of the month following the I 5-day appeal period (see E below) or 30-day time required by D.2 above, whichever is longer if no request for adjudicatory hearing is filed. If a request for adjudicatory hearing is filed, the permit will become effective on the first of the month following resolution of the appeal.

Rationale Page 47 of 47 Permit No. SC0004278 E. Adjudicatory Hearings Any person may submit a request for an administrative adjudicatory hearing to consider the final permit and its conditions. If you wish to request an administrative adjudicatory hearing, you must.do so in accordance with Regulation 61-72, Volume 25, S.C. Code of Laws, 1976, as amended, and the Rules of the Administrative Law Court (ALC). The request must be filed with the Clerk of the South Carolina Board of Health and Environmental Control, 2600 Bull Street, Columbia, South Carolina 29201, within fifteen (15) days following issuance of the permit. Service may be effected by personal delivery or by first class mail, but the request must be received by the Clerk on or before the fifteenth day. The following information, at a minimum, must be included in the request:

1. the name of the party or parties requesting the hearing and the issue(s) for which the hearing is requested;

2. the caption or other information sufficient to identify the permit decision being appealed; and

3. the relief requested.

In addition, the Administrative Law Court requires that a person requesting a contested case hearing must file a copy of the request and a filing fee in the amount of $250.00 with the Administrative Law Court at the following address: Clerk, Administrative Law Court 1205 Pendleton Street, Suite 224 P.O. Box 11667 Columbia, SC 29211 A petition for review of a decision to issue a new permit stays all actions for which the permit is a prerequisite. A petition for review of a decision to reissue a permit stays the entire permit; the conditions of the expiring/expired permit remain in effect until the appeal is resolved. Any party may petition the.ALC to allow all uncontested provisions of the permit to be placed into effect. Information pertaining to adjudicatory matters may be obtained by contacting the Legal Officie of the Department of Health and Environmental Control, 2600 Bull Street, Columbia, South Carolina orby calling 803-898-3350.}}