Text

Renewal of the Wastewater Discharge Permit
	ML12114A198
Person / Time
Site:	South Texas
Issue date:	04/17/2012
From:	Dannhardt S; South Texas
To:	; Document Control Desk, Office of Nuclear Reactor Regulation
References
	NOC-AE-12002840, STI: 33481360
	Download: ML12114A198 (52)
	v • d • e

Nuclear Operating Company South Tews PrqectFicctric G-ncratin$ Station PO. Box 289 Mdsworth, Tewas 77483 -A/\AA -

April 17, 2012 NOC-AE-12002840 File No.: G24.02 10CFR50 STI: 33481360 U. S. Nuclear Regulatory Commission Attention: Document Control Desk One White Flint North 11555 Rockville Pike Rockville, MD 20852-2738 South Texas Project Units 1 and 2 Docket Nos. STN 50-498 and STN 50-499 Renewal of the Wastewater Discharge Permit Pursuant to the South Texas Project Operating License, Appendix B (Environmental Protection Plan), Section 3.2, the South Texas Project submits the attached copy of the renewed Permit to Discharge Wastes (Permit No. 01908) from the Texas Commission on Environmental Quality. Appendix B requires that renewed permits be reported to the NRC within 30 days following approval.

Substantial changes made to the renewed permit include the addition of effluent limitations and monitoring requirements for new outfalls (002-006) associated with previously authorized discharges from the Main Cooling Reservoir (MCR) relief wells and the reinstatement of pH limits on internal discharges, excluding sanitary waste, to the MCR.

There are no commitments in this letter.

If you should have any questions on this matter, please contact me at (361) 972-8328.

S. L. Dannhardt Manager, Environmental MK/

Attachment:

Renewed Permit to Discharge Wastes C' k\

NOC-AE-1 2002840 Page 2 of 2 cc:

(paper copy) (electronic copy)

Regional Administrator, Region IV A. H. Gutterman, Esquire U. S. Nuclear Regulatory Commission Morgan, Lewis & Bockius LLP 1600 East Lamar Boulevard Arlington, TX 76011-4511 Balwant K. Singal U. S. Nuclear Regulatory Commission Balwant K. Singal John Ragan Senior Project Manager Chris O'Hara U.S. Nuclear Regulatory Commission Jim von Suskil One White Flint North (MS 8 B13) NRG South Texas LP 11555 Rockville Pike Rockville, MD 20852 Kevin Polio Senior Resident Inspector Richard Pena U. S. Nuclear Regulatory Commission City Public Service P. 0. Box 289, Mail Code: MN1 16 Wadsworth, TX 77483 C. M. Canady Peter Nemeth City of Austin Crain Caton & James, P.C.

Electric Utility Department 721 Barton Springs Road C. Mele Austin, TX 78704 City of Austin Richard A. Ratliff Texas Department of State Health Services Alice Rogers Texas Department of State Health Services

-"TPDES PERMIT NO. W00001908000

[ForTCEQ office use only -

EPA I.D.No. TX00649477 TEXAS COMMISSION ON ENVIRONMENTAL QUALITY P. O. Box 13087 This is a renewal of TPDES Permit Austin, Texas 78711-3087 No. W00001908000, issued on July 21, 2005.

PERMIT TO DISCHARGE WASTES under provisions of Section 402 of the Clean Water Act and Chapter 26 of the Texas Water Code STP Nuclear Operating Company whose mailing address is P.O. Box 289 Wadsworth, Texas 77483-0289 is authorized to treat and discharge wastes from South Texas Project Electric Generating Station (SIC 4911) located on Farm-to-Market Road 521, approximately 10 miles north of Matagorda Bay and 12 miles south southwest of the City of Bay City, Matagorda County, Texas 77483 via Outfall 001 directly to Colorado River Tidal in Segment No. 1401 of the Colorado River Basin; via Outfall 002 to the Plant Area Drainage Ditch (PADD); thence to Colorado River Tidal in Segment No. 1401; via Outfall 003 to an unnamed ditch; thence to an unnamed tributary of West Branch of Colorado River; thence to West Branch of Colorado River; thence to Matagorda Bay/Powderhom Lake in Segment No. 2451; via Outfall 004 to an. unnamed ditch; thence to the Colorado River Tidal in Segment 1401; via Outfall 005 to East Fork Little Robbins Sl6ugh; thence to Robbins Slough; thence to Robbins Lake; thence to Robbins Slough; thence to Crab Lake; thence to Crab Bayou; thence to Gulf Intracoastal Waterway (GIWW); thence to Matagorda Bay/Powderhom Lake in Segment 2451; and via Outfall 006 to Little Robbins Slough; thence to an unnamed pond; thence to Robbins Slough; thence to an unnamed lake; thence to Robbins Lake; thence to Robbins Slough; thence to Crab Lake; thence to Crab Bayou; thence to Gulf Intxacoastal Waterway (GIWW); thence to Matagorda Bay/Powderhorn Lake in Segment 2451 only according to effluent limitations, monitoring requirements and other conditions set forth in this permit, as well as the rules of the Texas Commission on Environmental Quality gTCEQ), the laws of the State of Texas, and other orders of the TCEQ. The issuance of this permit does not grant to the permittee the right to use private or public property for conveyance of wastewater along the discharge route described in this permit. This includes, but is not limited to, property belonging to any individual, partnership, corporation, or other entity

Neither does this permit authorize any invasion of personal rights nor any violation of federal, state, or local laws or regulations. It is the responsibility of the permittee to acquire property rights as may be necessary to use the discharge route.

This permit shall expire at midnight on December 1, 2014.

ISSUED DATE: April 5, 2012 For the Commission

EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS Outfall Number 00 1

1. During the period beginning upon date of issuance and lasting through date of expiration, the pernittee is authorized to discharge (*1) recirculated cooling water, cooling reservoir blowdown, previously monitored effluents (low volume wastes, metal cleaning wastes, storm water, treated sanitary sewage, car wash water, air conditioning condensate, and HVAC cooling tower blowdown), storm water, uncontaminated groundwater currently authorized under TPDES Construction General Permit TXR150000 (*6), and makeup water from the Colorado River subject to the following effluent limitations:

The daily average flow of effluent shall not exceed 144 million gallons per day (MGD). The daily maximum flow shall not exceed 200 MGD.

Effluent Characteristics Discharge Limitations Minimum Self-Monitoring Requirements Daily Average Daily Maximum Single Grab Report Daily Average and Daily Maximum mg/L mg/L mg/L Measurement Frequency Sample Type Flow (MGD) (Report) (Report) N/A Continuous (*2) Record Colorado River Flow (MGD) (*1) N/A (Report) N/A l/day (*2) Estimate Temperature (OF) (95)(*3) (97)(*3) N/A Continuous (*2) In-Situ Total Residual Chlorine (*4) N/A 0.05 N/A I/Week (*2) Grab (*5)

(*1) See Other Requirement No. 3.

(*2) When discharging.

(*3) See Other Requirement No. 8.

(*4) See Other Requirement No. 4

(*5) Samples shall be representative of periods of chlorination.

(*6) See Other Requirement No. 13.

2. The pH shall neither be less than 6.0 standard units nor be greater than 9.0 standard units and shall be monitored I/day (*2) by grab sample.

3. There shall be no discharge of floating solids or visible foam in other than trace amounts and no discharge of visible oil.

4. Effluent monitoring samples shall be taken at the following location: At Outfall 001, which is at a point in the blowdown line prior to entering Colorado River Tidal.

Page 2 of TPDES Permit No. WQ0001908000 STP Nuclear Operating Company

EFFLUENT LIMIvITATIONS AND MONITORING REOUIREMENTS Outfall Number 10 1

1. During the period beginning upon date of issuance and lasting through date of expiration, the permittee is authorized to discharge low volume waste sources (*1) commingled with previously monitored effluent from the metal cleaning waste system discharge subject to the following effluent limitations:

Volume: Flow variable.

Effluent Characteristics Discharge Limitations Minimum Self-Monitoring Requirements Daily Average Daily Maximum Single Grab Report Daily Average and Daily Maximum mg/L mg/L mg/L Measurement Frequency Sample Type Flow (MGD) (Report) (Report) N/A i/day Estimate Total Suspended Solids 30 100 100 1/week Grab (*2)

Oil and Grease 15 20 20 I/week Grab (*2)

(*1) See Other Requirements No. 9.

(*2) If more than one source is associated with this particular waste category, for analytes other than p1, grab samples from each source shall be analyzed, analytical values shall be combined on a flow weighted basis, and these calculated values shall be used to determine the "Daily Average" for the month. The highest analytical value of all grab samples for the monthly reporting period shall be reported as the "Daily Maximum." For pH, the minimum and the maximum values recorded among all the waste categories shall be reported.

2. The pH shall neither be less than 6.0 standard units nor be greater than 9.0 standard units and shall be monitored 1/week (*2) by grab sample.

3. There shall be no discharge of floating solids or visible foam in other than trace amounts and no discharge of visible oil.

4. Effluent monitoring samples shall be taken at the following location: At Outfall 101, where low volume waste sources (*1) commingled with previously monitored effluents are discharged from the neutalization basins prior to mixing with any other waste stream.

Page 2a of TPDES Permit No. WQ0001 908000 STP Nuclear Operating Company

EFFLUENT LIMITATIONS AND MONITORING REOUIREMENTS Outfall Number 201

1. During the period beginning upon date of issuance and lasting through date of expiration, the permittee is authorized to discharge low volume waste sources (*1) from the oily waste treatment system and storm water subject to.the following effluent limitations:

Volume: Flow variable.

Effluent Characteristics Discharge Limitations Minimum Self-Monitoring Requirements Daily Average Daily Maximum Single Grab Report Daily Average and Daily Maximum mg/L mg/L mg/L Measurement Frequency Sample Type Flow (MGD) (Report) (Report) N/A 1/day Estimate Total Suspended Solids 30 100 100 1/week Grab (*2)

Oil and Grease 15 20 20 I/week Grab (*2)

(*1) See Other Requirement No. 9.

(*2) If more than one source is associated with this particular waste category, for analytes other than pH, grab samples from each source shall be analyzed, analytical values shall be combined on a flow weighted basis, and these calculated values shall be used to determine the "Daily Average" for the month. The highest analytical value of all grab samples for the monthly reporting period shall be reported as the "Daily Maximum." For pH, the minimum and the maximum values recorded among all the waste categories shall be reported.

2. The pH shall neither be less than 6.0 standard units nor be greater than 9.0 standard units and shall be monitored l/week (*2) by grab sample.

3. There shall be no discharge of floating solids or visible foam in other than trace amounts and no discharge of visible oil.

4. Effluent monitoring samples shall be taken at the following location: Outfall 201, where low volume waste sources are discharged from the oily waste treatment system prior to mixing with any other waste stream.

Page 2b of TPDES Permit No. WQ0001908000 STP Nuclear Operating Company

EFFLUENT LIMITATIONS AND MONITORING REOU!REMLENTS Outfall Number 401

1. During the period beginning upon date of issuance and lasting through date of expiration, the permittee is authorized to discharge treated sanitary sewage commingled with car wash water and air conditioning condensate subject to the following effluent limitations:

Volume: Continuous and flow variable.

Effluent Characteristics Discharge Limitations Minimum Self-Monitoring Requirements Daily Average Daily Maximum Single Grab Report Daily Average and Daily Maximum mg/L mg/L mg/L Measurement Frequency Sample Type Flow (MGD) (Report) (Report) N/A 1/day Estimate Biochemical Oxygen Demand, 5-day 20 45 45 l/week Grab Total Suspended Solids 20 45 45 l/week Grab

2. The effluent shall contain a minimum chlorine residual of 1.0 mg/L after a detention time of at least 20 minutes (based on peak flow), and shall be monitored 1/week, by grab sample.

2. There shall be no discharge of floating solids or visible foam in other than trace amounts and no discharge of visible oil.

3. Effluent monitoring samples shall be taken at the following location: At Outfall 401, at discharge from the sewage treatment plant (West Sanitary Waste Treatment System) prior to mixing with any other waste stream.

Page 2c of TPDES Permit No. WQ000 1908000 ST? Nuclear Operating Company

FLUENT LIMITATIONS AND MONITORING REQUIREMENTS Outfall Number 501 I

During the period beginning upon date of issuance and lasting through date of expiration, the permittee is authorized to discharge metal cleaning waste (*1) subject to the following effluent limitations:

Volume: Intermittent and flow variable.

Effluent Characteristics Discharge Limitations Minimum Self-Monitoring Requirements Daily Average Daily Maximum Single Grab Report Daily Average and Daily Maximum mg/L mg/L mg/L Measurement Frequency Sample Type Flow (MGD) (Report) (Report) N/A 1/day (*2) Estimate Total Iron 1.0 1.0 1.0 I/week (*2) Grab Total Copper 0.5 1.0 1.0 I/week (*2) Grab

(*1) See Other Requirement No. 6.

(*2) When discharging.

2. The pH shall neither be less than 6.0 standard units nor be greater than 9.0 standard units and shall be monitored I/week (*2) by grab sample.

3. There shall be no discharge of floating solids or visible foam in other than trace amounts and no discharge of visible oil.

4. Effluent monitoring samples shall be taken at the following location: At Outfall 501, where metal cleaning wastes are discharged prior to mixing with any other waste stream.

Page 2d of TPDES Permit No. WQ0001908000 STP Nuclear Operating Company

EFFLUENT LIM]TATIONS AND MONITORING REOUIMEMENTS Outfall Number 601

1. During the period beginning upon date of issuance and lasting through date of expiration, the permittee is authorized to discharge treated sanitary sewage commingled with air conditioning condensate and HVAC cooling tower blowdown subject to the following effluent limitations:

Volume: Continuous and flow variable.

Effluent Characteristics Discharge Limitations Minimum Self-Monitoring Requirements Daily Average Daily Maximum Single Grab Report Daily Average and Daily Maximum mg/L mg/L mg/L Measurement Frequency Sample Type Flow (MGD) (Report) (Report) N/A 1/day Estimate Biochemical Oxygen Demand, 5-day 20 45 45 I/week Grab Total Suspended Solids 20 45 45 I/week Grab

2. The effluent shall contain a minimum chlorine residual of 1.0 mg/L after a detention time of at least 20 minutes (based on peak flow), and shall be monitored 1/week, by grab sample.

3. There shall be no discharge of floating solids or visible foam in other than trace amounts and no discharge of visible oil.

4. Effluent monitoring samples shall be taken at the following location: At Outfall 601, at the discharge from the sewage treatment plant (Training Sanitary Waste Treatment Facility) prior to mixing with any other waste stream.

Page 2e of TPDES Permit No. WQOOO1908000 ST? Nuclear Operating Company

EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS Outfall Number 002 1 During the period beginning upon date of issuance and lasting through date of expiration, the permittee is authorized to discharge effluent from the Reservoir Relief Wells (relief wells) for the Main Cooling Reservoir (MCR) and demineralized water from Instrumentation (*1) subject to the following effluent limitations (*2):

Volume: Continuous and flow variable.

Effluent Characteristics Discharge Limitations Minimum Self-Monitoring Requirements Daily Average Daily Maximum Single Grab Report Daily Average and Daily Maximum mg/L mg/I mg/L Measurement Frequency Sample Type Flow (MGD) (*3) (Report) (Report) N/A I/quarter (*4) Estimate Flow (MGD) (*3) (Report) (Report) N/A 1/six months (*5) Estimate Temperature (OF) (*8) N/A (97) N/A 1/quarter (*4) In-Situ Temperature (OF) (*8) N/A (97) N/A 1/six months (*5) In-Situ Total Residual Chlorine (*6) (*8) N/A 0.05 N/A 1/quarter (*4) Grab (*7)

Total Residual Chlorine (*6) (*8) N/A 0.05 N/A l/six months (*5) Crab (*7)

(*1) The Instrumentation is a dissolved oxygen analyzer.

(*2) See Other Requirement No. 19.

(*3) See Other Requirement No. 14.

(*4) Beginning upon permit issuance and lasting two years.

(*5) Beginning two years from the date of permit issuance and lasting through the date of permit expiration.

(*6) See Other Requirement No. 4.

(*7) Samples shall be representative of periods of chlorination.

(*8) See Other Requirement No. 15.

2. The pH shall neither be less than 6.0 standard units nor be greater than 9.0 standard units and shall be monitored I/quarter by grab sample (*8) beginning upon the permit issuance date and lasting two years, and 1/six months by grab sample (*8) beginning two years from the permit issuance date and lasting through the date of permit expiration.

3. There shall be no discharge of floating solids or visible foam in other than trace amounts and no discharge of visible oil.

4. Effluent monitoring samples shall be collected at the following locations: (a) for the demineralized water. from the Instrument Tube prior to commingling with other waters and (b) for the relief well water at the discharge of flowing relief well(s) prior to entering the Plant Area Drainage Ditch

(*3) (*8).

Page 2f of TPDES Permit No. WQ0001908000 STP Nuclear Operating Company

EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS OuWall Number 003

1. During the period beginning upon date of issuance and lasting through date of expiration, the permittee is authorized to discharge effluent from the relief wells for the MCR subject to the following effluent limitations (*1):

Volume: Continuous and flow variable.

Effluent Characteristics Discharge Limitations Minimum Self-Monitoring Requirements Daily Average Daily Maximum Single Grab Report Daily Average and Daily Maximum mg/L mg/L mg/L Measurement Frequency Sample Type Flow (MGD) (*2) (Report) (Report) N/A l/quarter (*3) Estimate Flow (MGD) (*2) (Report) (Report) N/A 1/six months (*4) Estimate Temperature (0F) (*7) N/A (97) N/A 1/quarter (*3) In-Situ Temperature (OF) (*7) N/A (97) N/A I/six months (*4) In-Situ Total Residual Chlorine (*5) (*7) N/A 0.05 N/A 1/quarter (*3) Grab (*6)

Total Residual Chlorine (*5) (*7) N/A 0.05 N/A 1/six months (*4) Grab (*6)

(*1) See Other Requirement No. 19.

(*2) See Other Requirement No. 14.

(*3) Beginning upon permit issuance and lasting two years.

(*4) Beginning two years from the date of permit issuance and lasting through the date of pennit expiration.

(*5) See Other Requirement No. 4.

(*6)

Samples shall be representative of periods of chlorination.

(*7)

See Other Requirement No. 15.

2. The pH shall neither be less than 6.0 standard units nor be greater than 9.0 standard units and shall be monitored l/quarter by grab sample (*7) beginning upon the permit issuance date and lasting two years, and 1/six months by grab sample (*7) beginning two years from the permit issuance date and last through the date of permit expiration.

3. There shall be no discharge of floating solids or visible foam in other than trace amounts and no discharge of visible oil.

4. Effluent monitoring samples shall be taken at the following location: At the discharge of flowing relief well(s) prior to mixing with the West Branch of Colorado River (*2) (*7).

Page 2g of TPDES Permit No. WQ0001 908000 SIP Nuclear Operating Company

EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS Outfall Number 004

1. During the period beginning upon date of issuance and lasting through date of expiration, the permittee is authorized to discharge effluent from the relief wells for the MCR and flow from the MCR spillway gates subject to the following effluent limitations (*1):

Volume: Continuous and flow variable.

Effluent Characteristics Discharge Limitations Minimum Self-Monitoring.Requirements Daily Average Daily Maximum Single Grab Report Daily Average and Daily Maximum mg/L mg/L mg/L Measurement Frequency Sample Type Flow (MGD) (*2) (Report) (Report) N/A 1/quarter (*3) Estimate Flow (MGD) (*2) (Report) (Report) N/A 1/six months (*4) Estimate Temperature (OF) (*7) N/A (97) N/A 1/quarter (*3) In-Situ Temperature (OF) (*7) N/A (97) N/A I/six months (*4) in-Situ Total Residual Chlorine (*5) (*7) N/A 0.05 N/A 1/quarter (*3) Grab (*6)

Total Residual Chlorine (*5) (*7) N/A 0.05 N/A I/six months (*4) Grab (*6)

(*1) See Other Requirement No. 19.

(*2) See Other Requirement No. 14.

(*3) Beginning upon permit issuance and lasting two years.

(*4) Beginning two years from the date of permit issuance and lasting through the date of permit expiration.

(*5) See Other Requirement No. 4.

(*6) Samples shall be representative of periods of chlorination.

(*7) See Other Requirement No. 15.

2. The pH shall neither be less than 6.0 standard units nor be greater than 9.0 standard units and shall be monitored I/quarter by grab sample (*7) beginning upon the permit issuance date and lasting two years, and 1/six months by grab sample (*7) beginning two years from the permit issuance date and last through the date of permit expiration.

3. There shall be no discharge of floating solids or visible foam in other than trace amounts and no discharge of visible oil.

4. Effluent monitoring samples shall be taken at the following location: (a) flow for the relief well water: at the discharge of flowing relief well(s) prior to entering the drainage ditch, (b) flow from the spillway gate leakage: at the basin prior to mixing with other waters, and (c) pH,total residual chlorine, and temperature: at a point in the MCR Spillway Channel after commingling of spillway gate leakage and relief well water, and prior to mixing with other waters.

Page 2h of TPDES Permit No. WQ0001908000 ST? Nuclear Operating Corapany

EFFLUENT LIMITATIONS AND MONITORING REQUREMENTS Outfall Number 005

1. During the period beginning upon date of issuance and lasting through date of expiration, the permittee is authorized to discharge effluent from the relief wells for the MCR subject to the following effluent limitations (*1):

Volume: Continuous and flow variable.

Effluent Characteristics Discharge Limitations Minimum Self-Monitoring Requirements Daily Average Daily Maximum Single Grab Report Daily Average and Daily Maximum mg/L mg/L mg/L Measurement Frequency Sample Type Flow (MGD) (*2) (Report) (Report) N/A I/quarter (*3) Estimate Flow (MGD) (*2) (Report) (Report) N/A 1/six months (*4) Estimate Temperature (OF) (*7) N/A (97) N/A 1/quarter (*3) In-Situ Temperature (OF) (*7) N/A (97) N/A 1/six months (*4) In-Situ Total Residual Chlorine (*5) (*7) N/A 0.05 N/A I/quarter (*3) Grab (*6)

Total Residual Chlorine (*5) (*7) N/A 0.05 N/A 1/six months (*4) Grab (*6)

(*1) See Other Requirement No. 19.

(*2) See Other Requirement No. 14.

(*3) Beginning upon permit issuance and lasting two years.

(*4) Beginning two years from the date of permit issuance and lasting through the date of permit expiration.

(*5) See Other Requirement No. 4.

(*6) Samples shall be representative of periods of chlorination.

(*7) See Other Requirement No. 15.

2. The pH shall neither be less than 6.0 standard units nor be greater than 9.0 standard units and shall be monitored 1/quarter by grab sample (*7) beginning upon the permit issuance date and lasting two years, and 1/six months by grab sample (*7) beginning two years from the permit issuance date and last through the date of permit expiration.

3. There shall be no discharge of floating solids or visible foam in other than trace amounts and no discharge of visible oil.

4. Effluent monitoring samples shall be taken at the following location: At the discharge of flowing relief well(s) prior to mixing with the East Fork Little Robbins Slough (*2) (*7).

Page 2i of TPDES Permit No. WQ0001908000 STP Nuclear Operating Company

EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS Outfall Number 006

1. During the period beginning upon date of issuance and lasting through date of expiration, the permittee is authorized to discharge effluent from the relief wells for the MCR subject to the following effluent limitations (*1):

Volume: Continuous and flow variable.

Effluent Characteristics Discharge Limitations Minimum Self-Monitoring Requirements Daily Average Daily Maximum Single Grab Report Daily Average and Daily Maximum mg/L mg/L mg/L Measurement Frequency Sample Type Flow (MGD) (*2) (Report) (Report) N/A 1/quarter (*3) Estimate Flow (MGD) (*2) (Report) (Report) N/A 1/six months (*4) Estimate Temperature (OF) (*7) N/A (97) N/A I/quarter (*3) In-Situ Temperature (OF) (*7) N/A (97) N/A 1/six months (*4) In-Situ Total Residual Chlorine (*5) (*7) N/A 0.05 N/A l/quarter (*3) Grab (*6)

Total Residual Chlorine (*5) (*7) N/A 0.05 N/A l/six months (*4) Grab (*6)

(*1) See Other Requirement No. 19.

(*2) See Other Requirement No. 14.

(*3) Beginning upon permit issuance and lasting two years.

(*4) Beginning two years from the date of permit issuance and lasting through the date of permit expiration.

(*5) See Other Requirement No. 4.

(*6) Samples shall be representative of periods of chlorination.

(*7) See Other Requirement No. 15.

2. The pH shall neither be less than 6.0 standardunits norbe greaterthan 9.0 standardunits and shall bemonitored I/quarterbygrab sample (*7) beginning upon the permit issuance date and lasting two years, and 1/six months by grab sample (*7) beginning two years from the permit issuance date and last through the date of permit expiration.

3. There shall be no discharge of floating solids or visible foam in other than trace amounts and no discharge of visible oil.

4. Effluent monitoring samples shall be taken at the following location: At the discharge of flowing relief well(s) prior to mixing with Little Robbins Slough near Well No. 6 (*2) (*7).

Page 2j of TPDES Permit No. WQ0001908000 S'I? Nuclear Operating Company

STP Nuclear Operating Company TPDES Permit No. WQ0001908000 DEFINITIONS AND STANDARD PERMIT CONDITIONS As required by Title 30 Texas Administrative Code (TAC) Chapter 305, certain regulations appear as standard conditions in waste discharge permits. 30 TAC §§305.121 - 305.129 (relating to Permit Characteristics and Conditions) as promulgated under the Texas Water Code (TWC) §§5.103 and 5.105, and the Texas Health and Safety Code (THSC) §§361.017 and 361.024(a), establish the characteristics and standards for waste discharge permits, including sewage sludge, and those sections of 40 Code of Federal Regulations (CFR) Part 122 adopted by reference by the Commission. The following text includes these conditions and incorporates them into this permit. All definitions in Texas Water Code §26.001 and 30 TAC Chapter 305 shall apply to this permit and are incorporated by reference. Some specific definitions of words or phrases used in this permit are as follows:

1. Flow Measurements

a. Annual average flow - the arithmetic average of all daily flow determinations taken within the preceding 12 consecutive calendar months, The annual average flow determination shall consist of daily flow volume determinations made by a totalizing meter, charted on a chart recorder, and limited to major domestic wastewater discharge facilities with a one million gallons per day or greater permitted flow.

b. Daily average flow - the arithmetic average of all determinations of the daily flow within a period of-one calendar month. The daily average flow determination shall consist of determinations made on at least four separate days. If instantaneous measurements are used to determine the daily flow, the determination shall be the arithmetic average of all instantaneous measurements taken during that month. Daily average flow determination for intermittent discharges shall consist of a minimum of three flow determinations on days of discharge.

c. Daily maximum flow - the highest total flow for any 24-hour period in a calendar month.

d. Instantaneous flow - the measured flow during the minimum time required to interpret the flow measuring device.

e. 2-hour peak flow (domestic wastewater treatment plants) - the maximum flow sustained for a two-hour period during the period of daily discharge. The average of multiple measurements of instantaneous maximum flow within a two-hour period may be used to calculate the 2-hour peak flow.

f. Maximum 2-hour peak flow (domestic wastewater treatment plants) - the highest 2-hour peak flow for any 24-hour period in a calendar month.

2. Concentration Measurements

a. Daily average concentration - the arithmetic average of all effluent samples, composite or grab as required by this permit, within a period of one calendar month, consisting of at least four separate representative measurements.

i. For domestic wastewater treatment plants - When four samples are not available in a calendar month, the arithmetic average (weighted by flow) of all values in the previous four consecutive month period consisiing of at least four measurements shall be utilized as the daily average concentration.

ii. For all other wastewater treatment plants - When four samples are not available in a calendar month, the arithmetic average (weighted by flow) of all values taken during the month shall be utilized as the daily average concentration.

b. 7-day average concentration - the arithmetic average of all effluent samples, composite or grab as required by this permit, within a period of one calendar week, Sunday through Saturday.

c. Daily maximum concentration - the maximum concentration measured on a single day, by the, sample type specified in the permit, within a period of one calendar month.

d. Daily discharge - the discharge of a pollutant measured during a calendar day or any 24-hour period that reasonably represents the calendar day for purposes of sampling. For pollutants with limitations expressed in terms of mass, the "daily discharge" is calculated as the total mass of the pollutant discharged over the sampling day. For pollutants with limitations expressed in other units of measurement, the "daily discharge" is calculated as the average measurement of the pollutant over the sampling day.

The "daily discharge" determination of concentration made using a composite sample shall be the concentration of the composite sample. When grab samples are used, the "daily discharge" determination of concentration shall be the arithmetic average (weighted by flow value) of all samples collected during that day.

e. Bacteria concentration (Fecal coliform, E. coli, or Enterococci) - the number of colonies of bacteria per 100 milliliters effluent. The daily average, bacteria concentration is a geometric mean of the values for the effluent samples collected in a calendar month.

Page 3

STP Nuclear Operating Company TPDES Permit No. WQ0001908000 The geometric mean shall be determined by calculating the nth root of the product of all measurements made in a calendar month, where n equals the number of measurements made; or computed as the antilogarithm of the arithmetic mean of the logarithms of all measurements of made in a calendar month. For any measurement of bacteria equaling zero, a substitute value of one shall made for input into either computation method. If specified, the 7-day average for bacteria is the geometric mean of the values for all effluent samples collected during a calendar week.

f. Daily average loading (lbs/day) - the arithmetic average of all daily discharge loading calculations during a period of one calendar month. These calculations must be made for each day of the month that a parameter is analyzed.

The daily discharge, in terms of mass (lbs/day), is calculated as (Flow, MGD x Concentration, mg/l x 8.34).

g. Daily maximum loading (lbs/day) - the highest daily discharge, in terms of mass (lbs/day), within a period of one calendar month.

3. Sample Type

a. Composite sample - For domestic wastewater, a composite sample is a sample made tip of a minimum of three effluent portions collected in a continuous 24-hour period or during the period of daily discharge if less than 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months , and combined in volumes proportional to flow, and collected at the intervals required by 30 TAC §319.9 (a). For industrial wastewater, a composite sample is a sample made up of a minimum of three effluent portions collected in a continuous 24-hour period or during the period of daily discharge if less than 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months , and combined in volumes proportional to flow, and collected at the intervals required by 30 TAC §319.9 (b).

b. Grab sample - an individual sample collected in less than 15 minutes.

4. Treatment Facility (facility) - wastewater facilities used in the conveyance, storage, treatment, recycling, reclamation and/or disposal of domestic sewage, industrial wastes, agricultural wastes, recreational wastes, or other wastes including sludge handling or disposal facilities under the jurisdiction of the Commission.

5. The term "sewage sludge" is defined as solid, semi-solid, or liquid residue generated during the treatment of domestic sewage in 30 TAC Chapter 312. This includes the solids that have not been classified as hazardous waste separated from wastewater by unit processes.

6. Bypass- the intentional diversion of a waste stream from any portion of a treatment facility.

MONITORING AND REPORTING REQUIREMENTS

1. Self-Reporting Monitoring results shall be provided at the intervals specified in the permit. Unless otherwise specified in this pernit or otherwise ordered by the Commission, the permittee shall conduct effluent sampling and reporting in accordance with 30 TAC §§319.4 - 319.12. Unless otherwise specified, a monthly effluent report shall be submitted each month, to the Enforcement Division (MC 224), by the 20th day of the following month for each discharge that is described by this permit whether or not a discharge is made for that month. Monitoring results must be reported on an approved self-report form that is signed and certified as required by Monitoring and Reporting Requirements No. 10.

As provided by state law, the permittee is subject to administrative, civil and criminal penalties, as applicable, for negligently or knowingly violating the Clean Water Act; TCW Chapters 26, 27, and 28; and THSC Chapter 361, including but not limited to knowingly making any false statement, representation, or certification on any report, record, or other document submitted or required to be maintained under this permit, including monitoring reports or reports of compliance or noncompliance, or falsifying, tampering with or knowingly rendering inaccurate any monitoring device or method required by this permit or violating any other requirement imposed by state or federal regulations.

2. Test Procedures

a. Unless otherwise specified in this permit, test procedures for the analysis of pollutants shall comply with procedures specified in 30 TAC §§319.11 - 319.12. Measurements, tests, and calculations shall be accurately accomplished in a representative manner.

b. All laboratory tests submitted to demonstrate compliance with this permit must meet the requirements of 30 TAC Chapter 25, Enviromnental Testing Laboratory Accreditation and Certification.

3. Records of Results

a. Monitoring samples and measurements shall be taken at times and in a manmer so as to be representative of the monitored activity.

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ST? Nuclear Operating Company TPDES Permit No. WQ0001908000

b. Except for records of monitoring information required by this permit related to the permittee's sewage sludge use and disposal activities, which shall be retained for a period of at least five years (or longer as required by 40 CFR Part 503), monitoring and reporting records, including strip charts and records of calibration and maintenance, copies of all records required by this permit, records of all data used to complete the application for this permit, and the certification required by 40 CFR §264.73(b)(9) shall be retained at the facility site, or shall be readily available for review by a TCEQ representative for a period of three years from the date of the record or sample, measurement, report, application or certification. This period shall be extended at the request of the Executive Director.

c. Records of monitoring activities shall include the following:

i. date, time, and place of sample or measurement; ii. identity of individual who collected the sample or made the measurement.

iii. date and time of analysis; iv. identity of the individual and laboratory who performed the analysis;

v. the technique or method of analysis; and vi. the results of the analysis or measurement and quality assurance/quality control records.

The period during which records are required to be kept shall be automatically extended to the date of the final disposition of any administrative or judicial enforcement action that may be instituted against the permittee.

4. Additional Monitoring by Permittee If the permittee monitors any pollutant at the location(s) designated herein more frequently than required by this permit using approved analytical methods as specified above, all results of such monitoring shall be included in the calculation and reporting of the values submitted on the approved self-report form. Increased frequency of sampling shall be indicated on the self-report form.

5. Calibration of Instruments All automatic flow measuring or recording devices and all totalizing meters for measuring flows shall be accurately calibrated by a trained person at plant start-up and as often thereafter as necessary to ensure accuracy, but not less often than annually unless authorized by the Executive Director for a longer period. Such person shall verify in writing that the device is operating properly and giving accurate results. Copies of the verification shall be retained at the facility site and/or shall be readily available for review by a TCEQ representative for a period of three years.

6. Compliance Schedule Reports Reports of compliance or noncompliance with, or any progress reports on, interim and final requirements contained in any compliance schedule of the permit shall be submitted no later than 14 days following each schedule date to the Regional Office and the Enforcement Division (MC 224).

7. Noncompliance Notification

a. In accordance with 30 TAC §305.125(9) any noncompliance that may endanger human health or safety, or the environment shall be reported by the permittee to the TCEQ. Report of such information shall be provided orally or by facsimile transmission (FAX) to the Regional Office within 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months of becoming aware of the noncompliance. A written submission of such information shall also be provided by the permittee to the Regional Office and the Enforcement Division (MC 224) within five working days of becoming aware of the noncompliance. The written submission shall contain a description of the noncompliance and its cause; the potential danger to human health or safety, or the environment; the period of noncompliance, including exact dates and times; if the noncompliance has not been corrected, the time it is expected to continue; and steps taken or planned to reduce, eliminate, and prevent recurrence of the noncompliance, and to mitigate its adverse effects.

b. The following violations shall be reported under Monitoring and Reporting Requirement 7.a.:

i. Unauthorized discharges as defined in Permit Condition 2(g).

ii. Any unanticipated bypass that exceeds any effluent limitation in the permit.

iii. Violation of a permitted maximum daily discharge limitation for pollutants listed specifically in the Other Requirements section of an Industrial TPDES permit.

c. In addition to the above, any effluent violation that deviates from the permitted effluent limitation by more than 40% shall be reported by the permittee in writing to the Regional Office and the Enforcement Division (MC 224) within 5 working days of becoming aware of the noncompliance.

d. Any noncompliance other than that specified in this section, or any required information not submitted or submitted incorrectly, shall be reported to the Enforcement Division (MC 224) as promptly as possible. For effluent limitation violations, noncompliances shall be reported on the approved self-report form.

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STP Nuclear Operating Company TPDES Permit No. WQ0001908000

8. In accordance with the procedures described in 30 TAC §§35.301 - 35.303 (relating to Water Quality Emergency and Temporary Orders) if the permittee knows in advance of the need for a bypass, it shall submit prior notice by applying for such authorization.

9. Changes in Discharges of Toxic Substances All existing manufacturing, commercial, mining, and silvicultural permittees shall notify the Regional Office, orally or by facsimile transmission within 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months , and both the Regional Office and the Enforcement Division (MC 224) in writing within five (5) working days, after becoming aware of or having reason to believe:

a. That any activity has occurred or will occur that would result in the discharge, on a routine or frequent basis, of any toxic pollutant listed at 40 CFR Part 122, Appendix D, Tables 11 and III (excluding Total Phenols) that is not limited in the permit, if that discharge will exceed the highest of the following "notification levels":

i. One hundred micrograms per liter (100 lig/L);

ii. Two hundred micrograms per liter (200 ýg/L) for acrolein and acrylonitrile; five hundred micrograms per liter (500 [+/-g/L) for 2,4-dinitrophenol and for 2-methyl-4,6-dinitrophenol; and one milligram per liter (1 mg/L) for antimony; iii. Five (5) times the maximum concentration value reported for that pollutant in the permit application; or iv. The level established by the TCEQ.

b. That any activity has occurred or will occur that would result in any discharge, on a nonroutine or infrequent basis, of a toxic pollutant that is not limited in the permit, if that discharge will exceed the highest of the following "notification levels":

i. Five hundred micrograms per liter (500 pg/L);

ii. One milligram per liter (1 mg[L) for antimony; iii. Ten (10) times the maximum concentration value reported for that pollutant in the permit application; or iv. The level established by the TCEQ.

10. Signatories to Reports All reports and other information requested by the Executive Director shall be signed by the person and in the manner required by 30 TAC §305.128 (relating to Signatories to Reports).

11. All Publicly Owned Treatment Works (POTWs) must provide adequate notice to the Executive Director of the following:

a. Any new introduction of pollutants into the POTW from an indirect discharger that would be subject to CWA §301 or §306 if it were directly discharging those pollutants;

b. Any substantial change in the volume or character of pollutants being introduced into that POTW by a source introducing pollutants into the POTW at the time of issuance of the permit; and

c. For the purpose of this paragraph, adequate notice shall include information on:

i. The quality and quantity of effluent introduced into the POTW; and ii. Any anticipated impact of the change on the quantity or quality of effluent to be discharged from the POTW.

PERMIT CONDITIONS

1. General

a. When the permittee becomes aware that it failed to submit any relevant facts in a permit application, or submitted incorrect information in an application or in any report to the Executive Director, it shall promptly submit such facts or information.

b. This permit is granted on the basis of the information supplied and representations made by the permittee during action on an application, and relying upon the accuracy and completeness of that information and those representations. After notice and opportunity for a hearing, this permit may be modified, suspended, or revoked, in whole or in part, in accordance with 30 TAC Chapter 305, Subchapter D, during its term for good cause including, but not limited to, the following:

i. Violation of any terms or conditions of this permit; ii. Obtaining this permit by misrepresentation or failure to disclose fully all relevant facts; or iii. A change in any condition that requires either a temporary or permanent reduction or elimination of the authorized discharge.

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STP Nuclear Operating Company TPDES Permit No. WQOO1908000

c. The permittee shall furnish to the Executive Director, upon request and within a reasonable time, any information to determine whether cause exists for amending, revoking, suspending, or terminating the permit. The permittee shall also ftumish to the Executive Director, upon request, copies of records required to be kept by the permit.

2. Compliance

a. Acceptance of the permit by the person to whom it is issued constitutes acknowledgment and agreement that such person will comply with all the terms and conditions embodied in the permit, and the rules and other orders of the Commission.

b. The permittee has a duty to comply with all conditions of the permit. Failure to comply with any permit condition constitutes a violation of the permit and the Texas Water Code or the Texas Health and Safety Code, and is grounds for enforcement action, for permit amendment, revocation, or suspension, or for denial of a permit renewal application or an application for a permit for another facility.

c. It shall not be a defense for a permittee in an enforcement action that itwould have been necessary to halt or reduce the permitted activity in order to maintain compliance with the conditions of the permit.

d. The permittee shall take all reasonable steps to minimize or prevent any discharge or sludge use or disposal or other permit violation that has a reasonable likelihood of adversely affecting human health or the environment.

e. Authorization from the Commission is required before beginning any change in the permitted facility or activity that may result in noncompliance with any permit requirements.

f. A permit may be amended, suspended and reissued, or revoked for cause in accordance with 30 TAC §§305.62 and 305.66 and TWC §7.302. The filing of a request by the permittee for a permit amendment, suspension and reissuance, or termination, or a notification of planned changes or anticipated noncompliance, does not stay any permit condition.

g. There shall be no unauthorized discharge of wastewater or any other waste. For the purpose of this permit, an unauthorized discharge is considered to be any discharge of wastewater into or adjacent to water in the state at any location not permitted as an outfall or otherwise defined in the Other Requirements section of this permit.

h. In accordance with 30 TAC §305.535(a), the permittee may allow any bypass to occur from a TPDES permitted facility that does not cause permitted effluent limitations to be exceeded or an unauthorized discharge to occur, but only if thl bypass is also for essential maintenance to assure efficient operation.

1. The permittee is subject to administrative, civil, and criminal penalties, as applicable, under Texas Water Code

§§7.051 - 7.075 (relating to Administrative Penalties), 7.101 - 7.111 (relating to Civil Penalties), and 7.141 - 7.202 (relating to Criminal Offenses and Penalties) for violations including, but not limited to, negligently or knowingly violating the federal CWA §§301, 302, 306, 307, 308, 318, or 405, or any condition or limitation implementing any sections in a permit issued under the CWA § 402, or any requirement imposed in a pretreatment program approved under the CWA §§402 (a)(3) or 402 (b)(8).

3. Inspections and Entry

a. Inspection and entry shall be allowed as prescribed in the TWC Chapters 26, 27, and 28, and THSC Chapter 361.

b. The members of the Commission and employees and agents of the Commission are entitled to enter any public or private property at any reasonable time for the purpose of inspecting and investigating conditions relating to the quality of water in the state or the compliance with any rule, regulation, permit, or other order of the Commission.

Members, employees, or agents of the Commission and Commission contractors are entitled to enter public or private property at any reasonable time to investigate or monitor or, if the responsible party is not responsive or there is an immediate danger to public health or the environment, to remove or remediate a condition related to the quality of water in the state, Members, employees, Commission contractors, or agents acting under this authority who enter private property shall observe the establishment's rules and regulations concerning safety, internal security, and fire protection, and if the property has management in residence, shall notify management or the person then in charge of his presence and shall exhibit proper credentials. If any member, employee, Commission contractor, or agent is refused the right to enter in or on public or private property under this authority, the Executive Director may invoke the remedies authorized in TWC §7.002. The statement above, that Commission entry shall occur in accordance with an establishment's rules and regulations concerning safety, internal security, and fire protection, is not grounds for denial or restriction of entry to any part of the facility, but merely describes the Commission's duty.to observe appropriate rules and regulations during an inspection.

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ST? Nuclear Operating Company TPDES Permit No. WQ0001908000

4. Permit Amendment and/or Renewal

a. The permittee shall give notice to the Executive Director as soon as possible of any planned physical alterations or additions to the permitted facility if such alterations or additions would require a permit amendment or result in a violation of permit requirements. Notice shall also be required under this paragraph when:

L The alteration or addition to a permitted facility may meet one of the criteria for determining whether a facility is a new source in accordance with 30 TAC §305.534 (relating to New Sources and New Dischargers); or ii. The alteration or addition could significantly change the nature or increase the quantity of pollutants discharged. This notification applies to pollutants that are subject neither to effluent limitations in the permit, nor to notification requirements in Monitoring and Reporting Requirements No. 9; iii. The alteration or addition results in a significant change in the permittee's sludge use or disposal practices, and such alteration, addition, or change may justify the application of permit conditions that are different from or absent in the existing permit, including notification of additional use or disposal sites not reported during the permit application process or not reported pursuant to an approved land application plan.

b. Prior to any facility modifications, additions, or expansions that will increase the plant capacity beyond the permitted flow, the permittee must apply for and obtain proper authorization from the Commission before commencing construction.

c. The permittee must apply for an amendment or renewal at least 180 days prior to expiration of the existing permit in order to continue a permitted activity after the expiration date of the permit. If an application is submitted prior to the expiration date of the permit, the existing permit shall remain in effect until the application is approved, denied, or returned. If the application is returned or denied, authorization to continue such activity shall terminate upon the effective date of the action. If an application is not submitted prior to the expiration date of the permit, the permit shall expire and authorization to continue such activity shall terminate.

d. Prior to accepting or generating wastes that are not described in the permit application or that would result in a significant change in the quantity or quality of the existing discharge, the permittee must report the proposed changes to the Commission. The permittee must apply for a permit amendment reflecting any necessary changes in permit conditions, including effluent limitations for pollutants not identified and limited by this permit.

e. In accordance with the TWC §26.029 (b), after a public hearing, notice of which shall be given to the permittee, the Commission may require the permittee, from time to time, for good cause, in accordance with applicable laws, to conform to new or additional conditions.

f. If any toxic effluent standard or prohibition (including any schedule of compliance specified in such effluent standard or prohibition) is promulgated under CWA §307(a) for a toxic pollutant that is present in the discharge and that standard or prohibition is more stringent than any limitation on the pollutant in this permit, this permit shall be modified or revoked and reissued to conform to the toxic effluent standard or prohibition. The permittee shall comply with effluent standards or prohibitions established under CWA §307(a)for toxic pollutants within the time provided in the regulations that established those standards or prohibitions, even if the permit has not yet been modified to incorporate the requirement.

5. Permit Transfer

a. Prior to any transfer of this permit, Commission approval must be obtained. The Commission shall be notified in writing of any change in control or ownership of facilities authorized by this permit. Such notification should be sent to the Applications Review and Processing Team (MC 148) of the Water Quality Division.

b. A permit may be transferred only according to the provisions of 30 TAC §305.64 (relating to Transfer of Permits) and 30 TAC §50.133 (relating to Executive Director Action on Application or WQMP update).

6. Relationship to Hazardous Waste Activities This permit does not authorize any activity of hazardous waste storage, processing, or disposal that requires a permit or other authorization pursuant to the Texas Health and Safety Code.

7. Relationship to Water Rights Disposal of treated effluent by any means other than discharge directly to water in the state must be specifically authorized in this permit and may require a permit pursuant to Texas Water Code Chapter 11.

8. Property Rights A permit does not convey any property rights of any sort, or any exclusive privilege.

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STP Nuclear Operating Company TPDES Permit No. WQ0001908000

9. Permit Enforceability The conditions of this permit are severable, and if any provision 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.

10. Relationship to Permit Application The application pursuant to which the permit has been issued is incorporated herein; provided, however, that in the event of a conflict between the provisions of this permit and the application, the provisions of the permit shall control.

11. Notice of Bankruptcy.

a. Each permittee shall notify the executive director, in writing, immediately following the filing of a voluntary or involuntary petition for bankruptcy under any chapter of Title 11 (Bankruptcy) of the United States Code (11 USC) by or against:

i. the permittee; ii. an entity (as that term is defined in 11 USC, §101(15)) controlling the permittee or listing the permit or permittee as property of the estate; or iii. an affiliate (as that term is defined in 11 USC, §101(2)) of the permittee.

b. This notification must indicate:

i. the name of the permittee; ii. the permit number(s);

iii. the bankruptcy court in which the petition for bankruptcy was filed; and iv. the date of filing of the petition.

OPERATIONAL REQUIREMENTS

1. The permittee shall at all times ensure that the facility and all of its systems of collection, treatment, and disposal are properly operated and maintained. This includes, but is not limited to, the regular, periodic examination of wastewater solids within the treatment plant by the operator in order to maintain an appropriate quantity and quality of solids inventory as described in the various operator training manuals and according to accepted industry standards for process control. Process control, maintenance, and operations records shall be retained at the facility site, or shall be readily available for review by a TCEQ representative, for a period of three years.

2. Upon request by the Executive Director, the permittee shall take appropriate samples and provide proper analysis in order to demonstrate compliance with Commission rules. Unless otherwise specified in this permit or otherwise ordered by the Commission, the permittee shall comply with all applicable provisions of 30 TAC Chapter 312 concerning sewage sludge use and disposal and 30 TAC §§319.21 - 319.29 concerning the discharge of certain hazardous metals.

3. Domestic wastewater treatment facilities shall comply with the following provisions:

a. The permittee shall notify the Municipal Permits Team, Wastewater Permitting Section (MC 148) of the Water Quality Division, in writing, of any facility expansion at least 90 days prior to conducting such activity.

b. The permittee shall submit a closure plan for review and approval to the Municipal Permits Team, Wastewater Permitting Section (MC 148) of the Water Quality Division, for any closure activity at least 90 days prior to conducting such activity. Closure is the act of permanently taking a waste management unit or treatment facility out of service and includes the permanent removal from service of any pit, tank, pond, lagoon, surface impoundment and/or other treatment unit regulated by this permit,

4. The permittee is responsible for installing prior to plant start-up, and subsequently maintaining, adequate safeguards to prevent the discharge of untreated or inadequately treated wastes during electrical power failures by means of alternate power sources, standby generators, and/or retention of inadequately treated wastewater.

5. Unless otherwise specified, the permittee shall provide a readily accessible sampling point and, where applicable, an effluent flow measuring device or other acceptable means by which effluent flow may be determined.

6. The permittee shall remit an annual water quality fee to the Commission as required by 30 TAC Chapter 21. Failure to pay the fee may result in revocation of this permit under TWC §7.302(b)(6).

7. Documentation For all written notifications to the Commission required of the permittee by this permit, the permittee shall keep and make available a copy of each such notification under the same conditions as self-monitoring data are required to be kept and made available.

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STP Nuclear Operating Company TPDES Permit No. WQ0001908000 Except for information required for TPDES permit applications, effluent data, including effluent data in permits, draft permits and permit applications, and other information specified as not confidential in 30 TAC §1.5(d), any information submitted pursuant to this permit may be claimed as confidential by the submitter. Any such claim must be asserted in the manner prescribed in the application form or by stamping the words "confidential business information" on each page containing such information. If no claim is made at the time of submission, information may be made available to the public without further notice. If the Commission or Executive Director agrees with the designation of confidentiality, the TCEQ will not provide the information for public inspection unless required by the Texas Attorney General or a court pursuant to an open records request. If the Executive Director does not agree with the designation of confidentiality, the person submitting the information will be notified.

8. Facilities that generate domestic wastewater shall comply with the following provisions; domestic wastewater treatment facilities at permitted industrial sites are excluded.

a. Whenever flow measurements for any domestic sewage treatment facility reach 75% of the permitted daily average or annual average flow for three consecutive months, the permittee must initiate engineering and financial planning for expansion and/or upgrading of the domestic wastewater treatment and/or collection facilities. Whenever the flow reaches 90% of the permitted daily average or annual average flow for three consecutive months, the permittee shall obtain necessary authorization from the Commission to commence construction of the necessary additional treatment and/or collection facilities. In the case of a domestic wastewater treatment facility that reaches 75% of the permitted daily average or annual average flow for three consecutive months, and the planned population to be served or the quantity of waste produced is not expected to exceed the design limitations of the treatment facility, the permittee shall submit an engineering report supporting this claim to the Executive Director of the Commission.

If in the judgment of the Executive Director the population to be served will not cause permit noncompliance, then the requirement of this section may be waived. To be effective, any waiver must be in writing and signed by the Director of the Enforcement Division (MC 149) of the Commission, and such waiver of these requirements will be reviewed upon expiration of the existing permit; however, any such waiver shall not be interpreted as condoning or excusing any violation of any permit parameter.

b. The plans and specifications for domestic sewage collection and treatment works associated with any domestic permit must be approved by the Commission, and failure to secure approval before commencing construction of such works or making a discharge is a violation of this permit and each day is an additional violation until approval has been secured.

c. Permits for domestic wastewater treatment plants are granted subject to the policy of the Commission to encourage the development of area-wide waste collection, treatment, and disposal systems. The Commission reserves the right to -amend any domestic wastewater permit in accordance with applicable procedural requirements to require the system covered by this permit to be integrated into an area-wide system, should such be developed; to require the delivery of the wastes authorized to be collected in, treated by or discharged from said system, to such area-wide system; or to amend this permit in any other particular to effectuate the Commission's policy. Such amendments may be made when the changes required are advisable for water quality control purposes and are feasible on the basis of waste treatment technology, engineering, financial, and related considerations existing at the time the changes are required, exclusive of the loss of investment in or revenues from any then existing or proposed waste collection, treatment or disposal system.

9. Domestic wastewater treatment plants shall be operated and maintained by sewage plant operators holding a valid certificate of competency at the required level as defined in 30 TAC Chapter 30.

10. For Publicly Owned Treatment Works (POTWs), the 30-day average (or monthly average) percent removal for BOD and TSS shall not be less than 85%, unless otherwise authorized by this permit.

11. Facilities that generate industrial solid waste as defined in 30 TAC §335.1 shall comply with these provisions:

a. Any solid waste, as defined in 30 TAC §335.1 (including but not limited to such wastes as garbage, refuse, sludge from a waste treatment, water supply treatment plant or air pollution control facility, discarded materials, discarded materials to be recycled, whether the waste is solid, liquid, or semisolid), generated by the permittee during the management and treatment of wastewater, must be managed in accordance with all applicable provisions of 30 TAC Chapter 335, relating to Industrial Solid Waste Management.

b. Industrial wastewater that is being collected, accumulated, stored,,or processed before discharge through any final discharge outfall, specified by this permit, is considered to be industrial solid waste until the wastewater passes through the actual point source discharge and must be managed in accordance with all applicable provisions of 30 TAC Chapter 335.

c. The permittee shall provide written notification, pursuant to the requirements of 30 TAC §335.8(b)(1), to the Corrective Action Section (MC 127) of the Remediation Division informing the Commission of any closure activity involving an Industrial Solid Waste Management Unit, at least 90 days prior to conducting such an activity.

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STP Nuclear Operating Company TPDES Permit No. WQOOO 1908000

d. Construction of any industrial solid waste management unit requires the prior written notification of the proposed activity to the Registration and Reporting Section (MC 129) of the Permitting and Remediation Support Division.

No person shall dispose of industrial solid waste, including sludge or other solids from wastewater treatment processes, prior to fulfilling the deed recordation requirements of 30 TAC §335.5.

e. The term "industrial solid waste management unit" means a landfill, surface impoundment, waste-pile, industrial furnace, incinerator, cement kiln, injection well, -container, drum, salt dome waste containment cavern, or any other structure vessel, appurtenance, or other improvement on land used to manage industrial solid waste.

f£ The permittee shall keep management records for all sludge (or other waste) removed from any wastewater treatment process. These records shall fulfill all applicable requirements of 30 TAC Chapter 335 and must include the following, as it pertains to wastewater treatment and discharge:

i. Volume of waste and date(s) generated from treatment process; ii. Volume of waste disposed of on-site or shipped off-site; iii. Date(s) of disposal; iv. Identity of hauler or transporter;

v. Location of disposal site; and vi. Method of final disposal.

The above records shall be maintained on a monthly basis. The records shall be retained at the facility site, or shall be readily available for review by authorized representatives of the TCEQ for at least five years.

12. For industrial facilities to which the requirements of 30 TAC Chapter 335 do not apply, sludge and solid wastes, including tank cleaning and contaminated solids for disposal, shall be disposed of in accordance with THSC Code Chapter 361, TCEQ Revision 08/2008 Page 11

STP Nuclear Operating Company TPDES Permit No, WQ0001908000 OTHER REQUIREMENTS I. The Executive Director has reviewed this action for consistency with the goals and policies of the Texas Coastal Management Program (CMP) in accordance with the regulations of the Coastal Coordination council (CCC) and has determined that the action is consistent with the applicable CMP goals and policies.

2. Violations of daily maximum limitations for the following pollutants shall be reported orally or by facsimile to TCEQ Region 12, within 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months from the time the permittee becomes aware of the violation followed by a written report within five working days to TCEQ Region 12 and the Enforcement Division (MC 224):

POLLUTANT MAL (mg/L)

Total Copper 0.010 Total Iron Test methods utilized shall be sensitive enough to demonstrate compliance with the permit effluent limitations.

Permit compliance/noncompliance determinations will be based on the effluent limitations contained in this permit with consideration given to the minimum analytical level (MAL) for the parameters specified above.

When an analysis of an effluent sample for any of the parameters listed above indicates no detectable levels above the MAL and the test method detection level is as sensitive as the specified MAL, a value of zero (0) shall be used for that measurement when determining calculations and reporting requirements for the self-reporting form. This applies to determinations of daily maximum concentration, calculations of loading and daily averages, and other reportable results.

When a reported value is zero (0) based on this MAL provision, the permittee shall submit the following statement with the self-reporting form either as a separate attachment to the form or as a statement in the comments section of the form.

"The reported value(s) of zero (0) for rlist parameter(s)] on the self-reporting form for minonitoring period date range] is based on the following conditions: 1) the analytical method used had a method detection level as sensitive as the MAL specified in the permit, and 2) the analytical results contained no detectable levels above the specified MAL."

When an analysis of an effluent sample for a parameter indicates no detectable levels and the test method detection level is not as sensitive as the MAL specified in the permit, or an MAL is not specified in the permit for that parameter, the level of detection achieved shall be used for that measurement when determining calculations and reporting requirements for the self-reporting form. A zero (0) may not be used.

3. For Outfall 001, the discharge from the cooling pond shall not exceed 12.5% of the flow of the Colorado River at the discharge point and there shall be no discharge from Outfall 001 when the receiving water flow adjacent to the plant is less than 800 cubic feet per second.

4. Total Residual Chlorine:

The term "total residual chlorine" (or total residual oxidants for intake water with bromides) means the value obtained using the amperometric method for total residual chlorine described in 40 CFR Part 136.

The permittee may use the DPD spectrophotometric method (EPA Method 330.5) upon written notification of the Executive Director, provided that EPA has modified the existing effluent limitation guidelines (40 CFR Part 423) or has provided the permittee with demonstration that this new method is appropriate for use by steam electric power generating facilities.

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STP Nuclear Operating Company TPDES Permit No. WQ0001908000 Total residual chlorine may not be discharged from any single generating unit for more than two hours per day unless the discharger demonstrates to the permitting authority that discharge for more than two hours is required for macroinvertebrate control.

Simultaneous multi-unit chlorination is permitted.

Samples for total residual chlorine analysis for discharges via Outfalls 002, 003, 004, and 005 may alternatively be collected from the relief wells located in the drainage area for Outfall 006.

Total residual chlorine sampling for reporting at Outfall 006 shall be conducted as follows:

If flow is observed in five or more relief wells located within the drainage area for Outfall 006, the permittee shall collect a grab sample from a minimum of five relief wells. If flow is observed in less than five relief wells, the permittee shall collect grab samples from all relief wells with observed flow. The maximum total residual chlorine concentration recorded shall be reported.

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

6. The term "metal cleaning waste" means any wastewater resulting from cleaning (with or without chemical compounds) any metal process equipment including, but not limited to, boiler tube cleaning, boiler fireside cleaning, and air preheater cleaning.

7. The term "chemical metal cleaning waste" means any wastewater resulting from the cleaning of any metal process equipment with chemical compounds, including, but not limited to, boiler tube cleaning.

8. For discharges via Outfall 001, the daily temperature discharge is defined as the flow weighted average temperature (FWAT) and shall be computed and recorded on a daily basis. FWAT shall be computed at equal time intervals not greater than two hours. The method of calculating FWAT is as follows:

F(INSTANTANEOUS FLOW X INSTANTANEOUS TEMPERATURE) 2](INSTANTANEOUS FLOW)

"Daily average temperature" shall be the arithmetic average of all FWAT's calculated during the calendar month. "Daily maximum temperature" shall be the highest FWAT calculated during the calendar month.

9. The term "low volume waste sources" means, taken collectively as if from one source, wastewaters from all sources except those for which specific limitations are otherwise established. Low volume waste sources include but are not limited to: wet scrubber air pollution control systems, ion exchange waste treatment systems, water treatment evaporator blowdown, laboratory and sampling streams, boiler blowdown, floor drains, cooling tower basin cleaning wastes and blowdown from recirculating house service water systems.

Sanitary and air conditioning wastes are not included.

10. This provision supersedes and replaces Provision 1, Paragraph 1 of Monitoring and Reporting Requirements found on Page 4 of this permit.

Monitoring results shall be provided at the intervals specified in the permit. Unless otherwise specified in this permit or otherwise ordered by the Commission, the permittee shall conduct effluent sampling and reporting in accordance with 30 TAC §§319.4 - 319.12.

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STP Nuclear Operating Company TPDES Permit No. WQ0001 908000 Unless otherwise specified, a monthly effluent report shall be submitted each month, to the location(s) specified on the reporting form or the instruction sheet, by the 25th day of the following month for each discharge which is described by this permit whether or not a discharge is made for that month.

For pollutants which are monitored annually, effluent reports shall be submitted in September of each year.

For pollutants which are monitored twice per year, the first effluent report shall be submitted six months after the date of plant start-up or discharge, whichever comes first, and subsequent reports every six months thereafter. For pollutants which are monitored four times per year, the first effluent report shall be submitted three months after the date of plant start-up or discharge, whichever comes first, and subsequent reports every three months thereafter.

Monitoring results must be reported on the approved TPDES self-reporting form, Discharge Monitoring Report (DMR) Form EPA No. 3320-1, signed and certified as required by Monitoring and Reporting Requirements No. 10.

11. The mixing zone for Outfall 001 is defined as a volume within a radius of 60 feet extending over the receiving waters from the point where discharge from each jet port enters the Colorado River. Chronic toxic criteria apply at the edge of the mixing zone.

No mixing zones are established for discharges via Outfalls 002, 003, 004, and 005 to intermittent streams.

The mixing zone for Outfall 006 is defined as 300 feet downstream and 100 feet upstream from the point of discharge. Chronic toxic criteria apply at the edge of the mixing zone.

12. Daily average concentration shall mean the arithmetic average (weighted by flow) of all effluent samples, composition or grab as required by this permit within a period of one calendar month, consisting of at least four separate representative measurements. When four samples are not available in a calendar month, the arithmetic average (weighted by flow) of the four most recent measurements or arithmetic average (weighted by flow) of all values taken during the month shall be utilized as the daily average concentration.

The provision supersedes and replaces Provision 2(a), Daily Average Concentration, as defined on page 3 of this permit.

13. The discharge of uncontaminated groundwater'generated during excavations for the construction of the new electric generating units 3 and 4 is authorized under TPDES Construction General Permit TXR150000. This groundwater may be discharged temporarily via Outfall 001, during the construction of units 3 and 4. This discharge shall not cause nuisance conditions.

14. Measurement of flow at Outfalls 002, 003, 004, 005, and 006 From the 770 relief wells surrounding the MCR, the permittee shall identify and document the relief wells covered in the drainage area for each of the outfalls. The flow estimate for each of the outfalls shall be determined as follows:

Outqfall 002 At the time of sample collection, the permittee shall determine the number of relief wells with observed flow (N) within the drainage area for this outfall. If flow is observed in five or more relief wells, the permittee shall measure the flow at a minimum of five relief wells before the discharge enters the drainage ditch. If flow is observed in less than five relief wells, the permittee shall measure the flow at all the flowing relief wells before the discharge enters the drainage ditch.

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STP Nuclear Operating Company TPDES Permit No. WQ0001908000 The average flow (Fl) shall be calculated as the sum of all the measured flows, divided by the number of flow measurements. Measured flow means the determination of volume of effluent accumulated over unit time (e.g., gallons per minute).

The flow for the demineralized water (F2) shall be measured at the Instrument Tube prior to commingling with other waters.

The estimated flow at Outfall 002 shall be reported as: (Fl

N + F2), in million gallons per day (MGD)..

Outfalls 003, 005, and 006 At the time of sample collection, the perrmittee shall determine the number of relief wells with observed flow (N) within the drainage area for each of the outfalls. If flow is observed in five or more relief wells at an outfall, the permittee shall measure the flow at a minimum of five relief wells before the discharge enters the drainage ditch. If flow is observed in less than five relief wells, the permittee shall measure the flow at all the flowing relief wells before the discharge enters the drainage ditch.

The average flow (Fx) at Outfall 'X' shall be calculated as the sum of all the measured flows, divided by the number of flow measurements.

The flow for Outfall 'X' shall be reported as: (Fx

N), in MGD.

Outfall 004 At the time of sample collection, the permittee shall determine the number of relief wells with observed flow (N) within the drainage area for this outfall. If flow is observed in five or more relief wells, the permittee shall measure the flow at a minimum of five relief wells before the discharge enters the drainage ditch. If flow is observed in less than five relief wells, the permittee shall measure the flow at all the flowing relief wells before the discharge enters the drainage ditch. The average flow (Fl) shall be calculated as the sum of all the measured flows, divided by the number of flow measurements.

The flow for the spillway gate leakage (F2) shall be estimated at the basin prior to commingling with other waters.

The flow for Outfall 004 shall be reported as: (FI

N + F2), in million gallons per day (MGD).

Within each outfall drainage area, the permittee shall clearly mark each relief well used for sampling with a number, and record the relief wells used for measurement and the wells counted as flowing during each monitoring event.

15. Measurement of pH, Temperature, and Total Residual Chlorine Samples for total residual chlorine analysis for discharges via Outfalls 002, 003, 004, and 005 may alternatively be collected from the relief wells located in the drainage area for Outfall 006 (See Other Requirement No. 4). The pH, temperature, and total residual chlorine for each of the outfalls shall be determined as follows:

Outfall 002 Effluent samples for the demineralized water shall be collected from the Instrument Tube. Effluent samples for the relief wells shall be collected using the following procedure titled Sampling of Relief Wells.

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STP Nuclear Operating Company TPDES Permit No. WQ0001908000 Analytical results for each of the parameters analyzed at the Instrument Tube and the relief wells shall be compared, and the maximum temperature, the maximum total residual chlorine, and the maximum and'the minimum pH values shall be used for compliance reporting purposes at this outfall.

Outfalls 003, 005, and 006 Effluent samples for the relief wells shall be collected using the following procedure titled Sampling of Relief Wells.

Outfall 004 Effluent samples shall be collected at a point in the MCR Spillway Channel after commingling of spillway gate leakage and relief well water, and prior to mixing with other waters.

Sampling ofRelief Wells If flow is observed in five or more relief wells located in the drainage area for the outfall, the permittee shall collect a grab sample from a minimum of five relief wells.

If flow is observed in less than five relief wells in the drainage area of the outfall, the permittee shall collect grab samples from all flowing relief wells. The maximum temperature, the maximum total residual chlorine, and the maximum and the minimum pH values shall be recorded at each outfall.

Within each outfall drainage area, the permittee shall clearly mark each relief well used for sampling with a number, and record the relief wells used for measurement and the wells counted as flowing during each monitoring event

16. The permittee shall continue to operate and maintain the makeup water intake structure configuration consistent with the letter submitted to the EPA by Houston Lighting & Power Co. dated 6/28/82 on the South Texas Project (STP) Reservoir Makeup Pumping Facility (RMPF) design (STP correspondence number ST-HL-FD-106) and approval of the RMPF design as BAT by the EPA in a letter dated 11/19/82) for minimizing Adverse Environmental Impact (AEI).

Specifically, the permittee shall adhere to the following conditions related to the operation, maintenance, and monitoring of the RMPF:

a. The pumps are operated intermittently based on reservoir level, river flow and water quality in accordance with standard operating procedures for the RMPF;

b. Diversion from the Colorado River is limited to 55% of the flow over 300 cubic feet per second to protect inflows during low river flow conditions in accordance with Certificate of Adjudication 14-5437A, which may be amended from time to time;

c. The screens must initiate a cleaning cycle whenever the water level differential (before and after the screens) exceeds eight inches;

d. Screens shall be in proper operating condition whenever the pumps are withdrawing water. If a screen must be taken out of service for maintenance, the differential pressure across the screens must maintain compliance with item c. above;

e. Screen shall be checked daily during makeup pumping operations; Page 16

STP Nuclear Operating Company TPDES Permit No. WQOOO 1908000

f. Water and impinged material resulting for the cleaning process shall enter a concrete trench from which material is directed to a trash basket or back to the river depending on the amount of debris being collected. Debris collected in the trash basket shall be disposed of appropriately;

g. Records (e.g., electronic logs, operating procedures, operator logs, etc.) documenting the operation and maintenance described above shall be kept onsite for a minimum of three years, and made available to the TCEQ personnel upon request.

If it is later determined that the current CWIS configuration is not representative of BTA for minimizing AEI, the permit may be reopened to incorporate additional requirements.

17. Wastewater discharged via Outfalls 002, 003, 004, 005, and 006 shall be sampled and analyzed for those parameters listed on Attachment 1 of this permit for a minimum of one sampling event. Sampling for flow shall be conducted in accordance with Other Requirement No. 14. Sampling for total residual chlorine shall be conducted in accordance with Other Requirement Numbers 4 and 15. Sampling for pH and temperature shall be conducted in accordance with Other Requirement No. 15. Attachment 1 shall be completed with the analytical results for Outfalls 002, 003, 004, 005, and 006 and sent to the TCEQ, Wastewater Permitting Section (MC-148), Industrial Team. Analytical testing for Outfalls 002, 003, 004, 005, and 006 shall be conducted within the first 90 days after date of permit issuance. Based on a technical review of the submitted analytical results, an amendment may be initiated by TCEQ staff to include additional effluent limitations, monitoring requirements, or both.

18. Discharges of storm water associated with industrial activity are not intended to be authorized under this permit at Outfalls 002, 003, 004, 005, and 006. These discharges are currently authorized under TPDES Multi-Sector General Permit (Authorization No. TXR05P472).

19. Flow measurements or sampling events conducted at Outfalls 002, 003, 004, 005, and 006 on days when the rainfall exceeds 0.1 inches during any 24-hour period shall not be used for compliance monitoring purposes. The permittee shall install a permanent rain gage at the plant site and keep records of rainfall that can be made available to the TCEQ personnel upon request.

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STP Nuclear Operating Company TPDES Permit No. WQOOO1908000 ATTACHMENT 1 TABLE 1 Outfall No.: [IC [G Effluent Concentration (mg/I)

Pollutants Samp. Sxamp. Samp. Samp. Average BOD (5-day)

CBOD (5-day)

Chemical Oxygen Demand Total Organic Carbon Dissolved Oxygen Ammonia Nitrogen Total Suspended Solids Nitrate Nitrogen Total Organic Nitrogen Total Phosphorus Oil and Grease Total Residual Chlorine Total Dissolved Solids Sulfate Chloride Fluoride Temperature (OF) pH (standard units; mmi/mnax)

Effluent Concentration (pg/l) MAL (tg/I)

Total Aluminum 30 Total Antimony 30 Total Arsenic 10 Total Barium 10 Total Beryllium 5 Total Cadmium 1 Total Chromium 10 Trivalent Chromium N/A Hexavalent Chromium 10 Total Copper 10 Cyanide 20 Total Lead 5 TotalMercury 0.2 Total Nickel 10 Total Selenium 10 Total Silver 2.0 Total Thallium 10 Total Zinc 5 Page 18

STP Nuclear Operating Company TPDES Permit No. WQ0001908000 CHRONIC BIOMONITORING REOUIREMENTS: MARINE The provisions of this Section apply to Outfall 001 for whole effluent toxicity testing (biomonitoring).

.Scope. Freuency and Methodology

a. The permittee shalltest the effluent for toxicity in accordance with the provisions below. Such testing will determine if an appropriately dilute effluent sample adversely affects the survival, reproduction, or growth of the test organisms.

b. The permittee shall conduct the following toxicity tests utilizing the test organisms, procedures and quality assurance requirements specified in this Part of the permit and in accordance with "Short-Term Methods for Estimating the Chronic Toxicity of Effluents and Receiving Waters to Marine and Estuarine Organisms, Third Edition" (EPA-821-R-02-014), or the most recent update:

1) Chronic static renewal survival and growth test using the mysid shrimp (Mysidopsis bahia) (Method 1007.0 or the most recent update thereof). A minimum of eight replicates with five organisms per replicate shall be used in the control and in each dilution. This test shall be conducted once per quarter.

2) Chronic static renewal 7-day larval survival and growth test using the inland silverside (Menidia beryllina) (Method 1006.0 or the most recent update thereof). A minimum of five replicates with eight organisms per replicate shall be used in the control and in each dilution. This test shall be conducted once per quarter.

The pernittee must perform and report a valid test for each test species during the, prescribed reporting period. An invalid test must be repeated during the same reporting period. An invalid test is herein defined as any test failing to satisfy the test acceptability criteria, procedures, and quality assurance requirements specified in the test methods and permit. All test results, valid or invalid, must be submitted as described below.

C. The permittee shall use five effluent dilution concentrations and a control in each toxicity test.

These additional effluent concentrations are 6%, 8%, 10%, 13%, and 17% effluent. The critical dilution, defined as 13% effluent, is the effluent concentration representative of the proportion of effluent in the receiving water during critical low flow or critical mixing conditions.

d. This permit may be amended to require a Whole Effluent Toxicity (WET) limit, a Chemical-Specific (CS) limit, a Best Management Practice (BMP), additional toxicity testing, and/or other appropriate actions to, address toxicity. The permittee may be required to conduct additional biomonitoring tests and/or a Toxicity Reduction Evaluation (TRE) if biomonitoring data indicate multiple numbers of unconfirmed toxicity events.

e. Testing Frequency Reduction

1) If none of the first four consecutive quarterly tests demonstrates significant lethal effects, the permittee may submit this information in writing and, upon approval, reduce the testing frequency to once per six months for the invertebrate test species and once per year for the vertebrate test species.

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STP Nuclear Operating Company TPDES Permit No. WQ0001908000

2) If one or more of the first four consecutive quarterly tests demonstrates significant sub-lethal effects, the permittee shall continue quarterly testing for that species until four consecutive quarterly tests demonstrate no significant sub-lethal effects. At that time, the permittee may apply for the appropriate testing frequency reduction for that species.

3) If one or more of the first four consecutive quarterly tests demonstrates significant lethal effects, the permittee shall continue quarterly testing for that species until the permit is reissued. If a testing frequency reduction had been previously granted and a subsequent test demonstrates significant lethal effects, the permittee will resume a quarterly testing frequency for that species until the permit is reissued.

2. Required Toxicity Testing Conditions

a. Test Acceptance - The permittee shall repeat any toxicity test, including the control and all effluent dilutions, which fail to meet the following criteria:

1) a control mean survival of 80% or greater;

2) a control mean dry weight of surviving mysid shrimp of 0.20 mg or greater;

3) a control mean dry weight for surviving unpreserved inland silverside of 0.50 mg or greater and 0.43 mg or greater for surviving preserved inland silverside;

4) a control Coefficient of Variation percent (CV%) of 40 or less in the growth and survival tests;

5) a critical dilution CV% of 40 or less in the growth and survival endpoints for either growth and survival test. However, if statistically significant lethal or nonlethal effects are exhibited at the critical dilution, a CV% greater than 40 shall not invalidate the test;

6) a Percent Minimum Significant Difference of 37 or less for mysid shrimp growth;

7) a Percent Minimum Significant Difference of 28 or less for inland silverside growth.

b. Statistical Interpretation

1) For the mysid shrimp and the inland silverside larval survival and growth tests, the statisti-cal analyses used to determine if there is a significant difference between the control and an effluent dilution shall be in accordance with the methods described in the "Short-Term Methods for Estimating the Chronic Toxicity of Effluents and Receiving Waters to Marine and Estuarine Organisms, Third Edition" (EPA-821-R 0 14), or the most recent update thereof.

2) The permittee is responsible for reviewing test concentration-response relationships to ensure that calculated test-results are interpreted and reported correctly. The EPA manual, "Method Guidance and Recommendation for Whole Effluent Toxicity (WET)

Testing (40 CFR Part 136)" (EPA 821 -B-00-004) provides guidance on determining the validity of test results.

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STP Nuclear Operating Company TPDES Permit No. WQOOO 1908000

3) If significant lethality is demonstrated (that is, there is a statistically significant difference in survival at the critical dilution when compared to the control), the conditions of test acceptability are met, and the survival of the test organisms are equal to or greater than 80% in the critical dilution and all dilutions below that, then the permittee shall report a survival No Observed Effect Concentration (NOEC) of not less than the critical dilution for the reporting requirements.

4) The NOEC is defined as the greatest effluent dilution at which no significant effect is demonstrated. The Lowest Observed Effect Concentration (LOEC) is defined as the lowest effluent dilution at which a significant effect is demonstrated. A significant effect is herein defined as a statistically significant difference at the 95% confidence level between the survival, reproduction, or growth of the test organism(s) in a specified effluent dilution compared to the survival, reproduction, or growth of the test organism(s) in the control (0% effluent).

5) The use of NOECs and LOECs assumes either a monotonic (continuous) concentration-response relationship or a threshold model of the concentration-response relationship.

For any test result that demonstrates a non-monotonic (non-continuous) response, the NOEC should be determined based on the guidance manual referenced in Item 2 above.

6) Pursuant to the responsibility assigned to the permrittee in Part 2.b.2), test results that demonstrate a non-monotonic (non-continuous) concentration-response relationship may be submitted, prior to the due date, for technical review. The above-referenced guidance manual will be used when making a determination of test acceptability.

7) Staff will review test results for consistency with rules, procedures, and permit requirements.

c. Dilution Water

1) Dilution water used in the toxicity tests shall be the receiving water collected as close to the point of discharge as possible but unaffected by the discharge.

2) Where the receiving water proves unsatisfactory as a result of pre-existing instream toxicity (i.e. fails to fulfill the test acceptance criteria of item 2.a.), the permittee may substitute synthetic dilution water for the receiving water in all subsequent tests provided the unacceptable receiving water test met the following stipulations:

a) a synthetic lab water control was performed (in addition to the receiving water control) which fulfilled the test acceptance requirements of item 2.a; b) the test indicating receiving water toxicity was carried out to completion (i.e., 7 days);

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STP Nuclear Operating Company TPDES Permit No. WQ0001908000 c) the permittee submitted all test results indicating receiving water toxicity with the reports and information required in Part 3 of this Section.

Upon approval, the permittee may substitute other appropriate dilution water with chemical and physical characteristics similar to that of the receiving water.

d. Samples and Composites

1) The pennittee shall collect a minimum of three flow-weighted 24-hour composite samples from Outfall 001. The second and thiud 24-hour composite samples will be used for the renewal of the dilution concentrations for each toxicity test. A 24-hour composite sample consists of a minimum of 12 effluent portions collected at equal time intervals representative of a 24-hour operating day and combined proportionally to flow, or a sample continuously collected proportionally to flow over a 24-hour operating day.

2) The permittee shall collect the 24-hour composite samples such that the samples are representative of any periodic episode of chlorination, biocide usage, or other potentially toxic substance discharged on an intermittent basis.

3) The permittee shall initiate the toxicity tests within 36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months after collection of the last portion of the first 24-hour composite sample. The holding time for any subsequent 24-hour composite sample shall not exceed 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months . Samples shall be maintained at a temperature of 0-6 degrees Centigrade during collection, shipping, and storage.

4) If Outfall 001 ceases discharging during the collection of effluent samples, the requirements for the minimum number of effluent samples, the minimum number of effluent portions, and the sample holding time, are waived during that sampling period.

However, the permittee must have collected an effluent composite sample volume sufficient to complete the required toxicity tests with renewal of the effluent. When possible, the effluent samples used for the toxicity tests shall be collected on separate days if the discharge occurs over multiple days. The effluent composite sample collection duration and the static renewal protocol associated with the abbreviated sample collection must be documented in the fall report.

3. Reporting All reports, tables, plans, summaries, and related correspondence required in any Part of this Section shall be submitted to the attention of the Standards Implementation Team (MC 150) of the Water Quality Division. All DMRs, including DMRs with biomonitoring data, should be sent to the Enforcement Division (MC 224).

a. The permittee shall prepare a full report of the results of all tests conducted pursuant to this permit in accordance with the Report Preparation Section of "Short-Term Methods for Estimating the Chronic Toxicity of Effluents and Receiving Waters to Marine and Estuarine Organisms, Second Edition" (EPA 600-4-91-003), or the most recent update, for every valid and invalid toxicity test initiated whether carried to completion or not. All full reports shall be retained for 3 years at the plant site and shall be available for inspection by TCEQ personnel;

b. A full report must be submitted with the first valid biomonitoring test results for each test species and with the first test results any time the permittee subsequently employs a different test laboratory.

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STP Nuclear Operating Company TPDES Permit No. WQ0001 908000 Full reports need not be submitted for subsequent testing unless specifically requested. The permittee shall routinely report the results of each biomonitoring test on the Table 1 forms provided with this permit. All Table i reports must include the information specified in the Table I form attached to this permit.

1) Annual biomonitoring test results are due on or before January 20th for biomonitoring conducted during the previous 12 month period.

2) Semiannual biomonitoring test results are due on or before July 20th and January 20th for biomonitoring conducted during the previous 6 month period.

3) Quarterly biomonitoring test results are due on or before April 20th, July 20th, October 20th, and January 20th, for biomonitoring conducted during the previous calendar quarter.

4) Monthly biomonitoring test results are due on or before the 20th day of the month following sampling.

c. Enter the following codes on the DMR for the appropriate parameters for valid tests only:

1) For the mysid shrimp, Parameter TLP3E, enter a "1" if the NOEC for survival is less than the critical dilution; otherwise, enter a "0."

2) For the mysid shrimp, Parameter TOP3E, report the NOEC for survival.

3) For the mysid shrimp, Parameter TXP3E, report the LOEC for survival.

4) For the mysid shrimp, Parameter TWP3E, enter a "1" if the NOEC for growth is less than the critical dilution; otherwise, enter a "0."

5) For the mysid shrimp, Parameter TPP3E, report the NOEC for growth.

6) For the mysid shrimp, Parameter TYP3E, report the LOEC for growth.

7) For the inland silverside, Parameter TLP6B, enter a "1"if the NOEC for survival is less than the critical dilution; otherwise, enter a "0."

8) For the inland silverside, Parameter TOP6B, report the NOEC for survival.

9) For the inland silverside, Parameter TXP6B, report the LOEC for survival.

10) For the inland silverside, Parameter TWP6B, enter a "1" if the NOEC for growth is less than the critical dilution; otherwise, enter a "0."

11) For the inland silverside, Parameter TPP6B, report the NOEC for growth.

12) For the inland silverside, Parameter TYP6B, report the LOEC for growth.

d. Enter the following codes on the DMR for retests only:

1) For retest number 1, Parameter 22415, enter a "1" if the NOEC for survival is less than the critical dilution; otherwise, enter a "0."

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STP Nuclear Operating Company TPDES Permit No. WQ0001908000

2) For retest number 2, Parameter 22416, enter a "1" if the NOEC for survival is less than the critical dilution; otherwise, enter a "0."

4. Persistent Toxicity The requirements of this Part apply only when a test demonstrates a significant effect at the critical dilution. A significant effect is defined as a statistically significant difference, at the 95% confidence level, between a specified endpoint (survivalor growth) of the test organism in a specified effluent dilution when compared to the specified endpoint of the test organism in the control. Significant lethality is defined as a statistically significant difference in survival at the critical dilution when compared to the survival of the test organism in the control. Significant sublethality is defined as a statistically significant difference in growth at the critical dilution when compared to the growth of the test organism in the control.

a. The permittee shall conduct a total of 2 additional tests (retests) for any species that demonstrates a significant effect (lethal or sublethal) at the critical dilution. The two retests shall be conducted monthly during the next two consecutive months. The permittee shall not substitute either of the two retests in lieu of routine toxicity testing. All reports shall be submitted within 20 days of test completion. Test completion is defined as the last day of the test. The retests shall also be reported on the DMRs as specified in Part 3.d.

b. If the retests are performed due to a demonstration of significant lethality, and one or both of the two retests specified in item 4.a. demonstrates significant lethality, the permittee shall initiate the TRE requirements as specified in Part 5. The provisions of item 4.a. are suspended upon completion of the two retests and submittal of the TRE Action Plan and Schedule defined in Part 5.

If neither test demonstrates significant lethality and the permittee is testing under the reduced testing frequency provision of Part 1.e., the permiittee shall return to a quarterly testing frequency for that species.

c. If the two retests are performed due to a demonstration of significant sublethality, and one or both of the two retests specified in item 4.a. demonstrates significant lethality, the permittee shall again perform two retests as stipulated in item 4.a.

d. If the two retests are performed due to a demonstration of significant sublethality, and neither test demonstrates significant lethality, the permittee shall continue testing at the quarterly frequency until such time that the permittee can invoke the reduced testing frequency provision specified in Part i.e.

e. Regardless of whether retesting for lethal or sublethal effects, or a combination of the two, no more than one retest per month is required for a species.

5. Toxicity Reduction Evaluation

a. Within 45 days of the retest that demonstrates significant lethality, the perrnittee shall submit a General Outline for initiating a Toxicity Reduction Evaluation (TRE). The outline shall include, but not be limited to, a description of project personnel, a schedule for obtaining consultants (if needed), a discussion of influent and/or effluent data available for review, a sampling and analytical schedule, and a proposed TEE initiation date.

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STP Nuclear Operating Company TPDES Permit No. WQOOO 1908000

b. Within 90 days of the retest that demonstrates significant lethality, the permittee shall submit a TRE Action Plan and Schedule for conducting a TRE. The plan shall specify the approach and methodology to be used in performing the TRE. A TRE is a step-wise investigation combining toxicity testing with physical and chemical analysis to determine actions necessary to eliminate or reduce effluent toxicity to a level not effecting significant lethality at the critical dilution.

The TRE Action Plan shall lead to the successful elimination of significant lethality for both test species defined in item 1.b. As a minimum, the TRE Action Plan shall include the following:

1) Specific Activities - The TRE Action Plan shall specify the approach the permittee intends to utilize in conducting the TRE, including toxicity characterizations, identifications, confirmations, source evaluations, treatability studies, and/or alternative approaches. When conducting characterization analyses, the permittee shall perform multiple characterizations and follow the procedures specified in the document entitled, "Toxicity Identification Evaluation: Characterization of Chronically Toxic Effluents, Phase I" (EPA/600/6-91/005F), or alternate procedures. The permittee shall perform multiple identifications and follow the methods specified in the documents entitled, "Methods for Aquatic Toxicity Identification Evaluations, Phase II Toxicity Identification Procedures for Samples Exhibiting Acute and Chronic Toxicity" (EPA/600/R-92/080) and "Methods for Aquatic Toxicity Identification Evaluations, Phase III Toxicity Confirmation Procedures for Samples Exhibiting Acute and Chronic Toxicity" (EPA/600/R-92/08 1). All characterization, identification, and confirmation tests shall be conducted in an orderly and logical progression;

2) Sampling Plan - The TRE Action Plan should describe sampling locations, methods, holding times, chain of custody, and preservation techniques. The effluent sample volume collected for all tests shall be adequate to perform the toxicity characterization/

identification/ confirmation procedures, and chemical-specific analyses when the toxicity tests show significant lethality. Where the permittee has identified or suspects specific pollutant(s) and/or source(s) of effluent toxicity, the permittee shall conduct, concurrent with toxicity testing, chemical-specific analyses for the identified and/or suspected pollutant(s) and/or source(s) of effluent toxicity;

3) Quality Assurance Plan - The TRE Action Plan should address record keeping and data evaluation, calibration and standardization, baseline tests, system blanks, controls, duplicates, spikes, toxicity persistence in the samples, randomization, reference toxicant control charts, as well as mechanisms to detect artifactual toxicity; and

4) Project Organization - The TRE Action Plan should describe the project staff, project manager, consulting engineering services (where applicable), consulting analytical and toxicological services, etc.

c. Within 30 days of submittal of the TRE Action Plan and Schedule, the permittee shall implement the TRE with due diligence.

d. The permittee shall submit quarterly TRE Activities Reports concerning the progress of the TRE. The quarterly reports are due on or before April 20th, July 20th, October 20th, and January 20th. The report shall detail information regarding the TRE activities including:

1) results and interpretation of any chemical-specific analyses for the identified and/or suspected pollutant(s) performed during the quarter; Page 25

STP Nuclear Operating Company TPDES Permit No. WQ0001908000

2) results and interpretation of any characterization, identification, and confirmation tests performed during the quarter;

3) any data and/or substantiating documentation which identifies the pollutant(s) and/or source(s) of effluent toxicity;

4) results of any studies/evaluations concerning the treatability of the facility's effluent toxicity;

5) any data which identifies effluent toxicity control mechanisms that will reduce effluent toxicity to the level necessary to meet no significant lethality at the critical dilution; and

6) any changes to the initial TRE Plan and Schedule that are believed necessary as a result of the TRE findings.

Copies of the TRE Activities Report shall also be submitted to the U.S. EPA Region 6 office.

e. During the TRE, the permittee shall perform, at a minimum, quarterly testing using the more sensitive species; testing for the less sensitive species shall continue at the frequency specified in Part L.b.

f. If the effluent ceases to effect significant lethality (herein as defined below) the permittee may end the TRE. A "cessation of lethality" is defined as no significant lethality for a period of 12 consecutive months with at least monthly testing. At the end of the 12 months, the permittee shall submit a statement of intent to cease the TRE and may then resume the testing frequency specified in Part 1.b. The permittee may only apply the "cessation of lethality" provision once.

This provision accommodates situations where operational errors and upsets, spills, or sampling errors triggered the TRE, in contrast to a situation where a single toxicant or group of toxicants cause lethality. This provision does not apply as a result of corrective actions taken by the permittee. "Corrective actions" are herein defined as proactive efforts which eliminate or reduce effluent toxicity. These include, but are not limited to, source reduction or elimination, improved housekeeping, changes in chemical usage, and modifications of influent streams and/or effluent treatment.

The permittee may only apply this cessation of lethality provision once. If the effluent again demonstrates significant lethality to the same species, the permit will be amended to add a WET limit with a compliance period, if appropriate. However, prior to the effective date of the WET limit, the perm-ittee may apply for a permit amendment removing and replacing the WET limit with an alternate toxicity control measure by identifying and confirming the toxicant and/or an appropriate control measure.

g. The permittee shall complete the TRE and submit a Final Report on the TRE Activities no later than 28 months from the last test day of the retest that confirmed significant lethal effects at the critical dilution. The permittee may petition the Executive Director (in writing) for an extension of the 28-month limit. However, to warrant an extension the permittee must have demonstrated due diligence in their pursuit of the TIE/TRE and must prove that circumstances beyond their control stalled the TIE/TRE. The report shall provide information pertaining to the specific control mechanism(s) selected that will, when implemented, result in reduction of effluent toxicity to no significant lethality at the critical dilution. The report will also provide a specific corrective action schedule for implementing the selected control mechanism(s).

Page 26

STP Nuclear Operating Company TPDES Permit No. WQ000 1908000 A copy of the TRE Final Report shall also be submitted to the U.S. EPA Region 6 office.

h. Based upon the results of the TRE and proposed corrective actions, this permit may be amended to modify the biomonitoring requirements, where necessary, to require a compliance schedule for implementation of corrective actions, to specify a WET limit, to specify a BMP, and/or to specify CS limits.

Page 27

STP Nuclear Operating Company TPDES Permnit No. WQ0001908000 TABLE 1 (SHEET 1 OF 4)

MYSID SHRIMP SURVIVAL AND GROWTH Date Time Date Time Dates and Times No. 1 FROM: TO:

Composites Collected No. 2 FROM: TO:

No. 3 FROM: TO:

Test initiated: am/pm date Dilution water used: _Receiving water ___ Synthetic dilution water MYSID SHRIMP SURVIVAL

-- , eret l Rpli.cate. Cambers P icei

-, -,;,++ Sr iva in-l -

-K71I J>Q :u ~:Sirvi

~ l-rn i~i~g~i;,:,iii}!i~......

i~ii~iii

..!i... .....

0%it V a =jj[~[

sadr deito 100

__ ___ [ ] Imean_ _._..........

.t!i~~iffunt)N~ Lj1[T7[EI 111111BI[I1OI[_]I]KO] ~7 I"i

_EI[__ 4~ 8 -7dy- t. _RM

-+6 2, '

-_ -_-_--.,.__ "."Z. --- - ' _ _ _ "-

E- ]0 7 :E." =

-- i s _

1 _ e-_

r_

r i-%.17/

... ...ul ........ 1

-5 Page 28

STP Nuclear Operating Company TPDES Permit No. WQ0001908000 TABLE 1 (SHEET 2 OF 4)

MYSID SHRIMP SURVIVAL AND GROWTH DATA TABLE FOR GROWTH OF MYSID SHRIMP (Continued)

- *::- *:*': * -"**:o* *-".. ...... 6o ....... . *%: : -ý:* ':":.ý "..

, : :*.° 6%hy 8% -- O%-

; . ........ ° .* -":--*

3-: w7. :

~

~~ ~ ============ ~ ~ ~ ~ ~~

~ ~ :.:..==*::: .......a -*:.

ty Weightausmn)rt-tes Dra Bonerronti w eightBnfirn imlgadu eni)s anpreplicate:~abr effluent corepndn eolaiy CRITICALDILUTION_(3__):_____ YE1 ___N

1. Dunnett's Procedure or Steel's Many-One Rank Test or Wilcoxon Rank Sum Test (with Bonferroni adjustment) or t-test (with Bonferroni adjustment) as appropriate:

Is the mean survival at 7 days significantly less (p=0.05) than the control survival for the %

effluent corresponding to lethality?

CRITICAL DILUTION (13%): ___YES NO

2. Dunnett's Procedure or Steel's Many-One Rank Test or Wilcoxon Rank Sum Test (with Bonferroni adjustment) or 1-test (with Bonferroni adjustment) as appropriate:

Is the mean dry weight (growth) at 7 days significantly less (p=0.05) than the control's dry weight (growth) for the %effluent corresponding to non-lethal effects?

CRITICAL DILUTION (13%): YES NO

3. Enter percent effluent corresponding to each NOECTLOEC below:

a.) NOEC survival = % effluent b.) LOEC survival = % effluent c.) NOEC growth = % effluent d.) LOEC growth = % effluent Page 29

ST? Nuclear Operating Company TPDES Permit No. WQ0001908000 TABLE 1 (SHEET 3 OF 4)

INLAND SILVERSIDE MINNOW LARVAL SURVIVAL AND GROWTH TEST Date Time Date Time Dates and Times No. 1 FROM: TO:

Composites Collected No. 2 FROM: TO:

No. 3 FROM: TO:

Test initiated: alpm date Dilution water used: Receiving water ___ Synthetic Dilution water INLAND SILVERSIDE SURVIVAL

..... n. t~hmbr J §vv -Sria n_ l V~

Z-[EJ~

7

-- 4 h . .~7

-. =A;dys

_ ':77_

-- ___] ___I 24__~

_______I ____________I_______

Bi ' ar ii -, =

IL1E H:Ah

Coefficient of Variation = standard deviation x 100/mean II _

Page 30

STP Nuclear Operating Company TPDES Permit No. WQOOO 1908000 TABLE 1 (SHEET 4 OF 4)

INLAND SILVERSIDE LARVAL SURVIVAL AND GROWTH TEST INLAND SILVERSIDE GROWTH

.... ~... . . .... .. *+': +"".... * .. ii!~l! i..

Ave.*e Dry Weg ..- i grams piae.-Man E fre ..*-

'*+'+?*.--...::-*+x+*_- Weights C -

Bofroiadutet r -et(ihcBonie-rn adutet)aprpriate C....... DILUTIO (1%) YES NO

_ _ _CLDIUIN(3%:_ E __ INO eflue CRITICL DILTION LOesponing 13_____

t lethalty? YE____N Weiht are fr __percentervedt lavaor unres o ed ervig N~larvabeow a.oNOErsronivadjsmet or t-es (wteofflerrnitdutetsaporae

(. OCgrowth)o th % effluent crepnigt o-ehlefcs d.) LOEC growth = % effluent Page 31

STP Nuclear Operating Company TPDES Permit No. WQ0001 908000 24-HOUR ACUTE BIOMONITORING REQUIREMENTS: MARINE The provisions of this section apply to Outfall 001 for whole effluent toxicity testing (biomonitoring)

I Scope, Frequency and Methodoloav

a. The permittee shall test the effluent for lethality in accordance with the provisions in this Section. Such testing will determine compliance with the Surface Water Quality Standard, 307.6(e)(2)(B), of greater than 50% survival of the appropriate test organisms in 100% effluent for a 24-hour period.

b. The toxicity tests specified shall be conducted once per six months. The permittee shall conduct the following toxicity tests utilizing the test organisms, procedures, and quality assurance requirements specified in this section of the permit and in accordance with "Methods for Measuring the Acute Toxicity of Effluents and Receiving Waters to Freshwater and Marine Organisms, Fifth Edition" (EPA-821-R-02-012), or the most recent update thereof:

1) Acute 24-hour static toxicity test using the mysid shrimp (Mysidopsis bahia). A minimum of five replicates with eight organisms per replicate shall be used in the control and in each dilution.

2) Acute 24-hour static toxicity test using the inland silverside (Menidia beryllina). A minimum of five replicates with eight organisms per replicate shall be used in the control and in each dilution.

A valid test result must be submitted for each reporting period. The permittee must report, and then repeat, an invalid test during the same reporting period. The repeat test shall include the control and the 100% effluent dilution and use the appropriate number of organisms and replicates, as specified above. An invalid test is herein defined as any test failing to satisfy the test acceptability criteria, procedures, and quality assurance requirements specified in the test methods and permit.

C. In addition to an appropriate control, a 100% effluent concentration shall be used in the.toxicity tests. The control and/or dilution water shall consist of standard, synthetic, moderately hard, reconstituted water.

d. This permit may be amended to require a Whole Effluent Toxicity (WET) limit, a Best Management Practice (BMP), Chemical-Specific (CS) limits, additional toxicity testing, and/or other appropriate actions to address toxicity. The permittee may be required to conduct additional biomonitoring tests and/or a Toxicity Reduction Evaluation (TRE) if biomonitoring data indicate multiple numbers of unconfirmed toxicity events.

2. Required Toxicity Testing Conditions

a. Test Acceptance - The permittee shall repeat any toxicity test, including the control, if the control fails to meet a mean survival equal to or greater than 90%.

b. Dilution Water - In accordance with item I.c., the control and/or dilution water shall consist of standard, synthetic, moderately hard, reconstituted seawater.

c. Samples and Composites Page 32

STP Nuclear Operating Company TPDES Permit No. WQ0001908000

1) The permittee shall collect one flow-weighted 24-hour composite sample from Outfall 001. A 24-hour composite sample consists of a minimum of 12 effluent portions collected at equal time intervals representative of a 24-hour operating day and combined proportional to flow, or a sample continuously collected proportional to flow over a 24-hour operating day.

2) The permittee shall collect the 24-hour composite samples such that the samples are representative of any periodic episode of chlorination, biocide usage, or other potentially toxic substance discharged on an intermittent basis.

3) The permittee shall initiate the toxicity tests within 36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months after collection of the last portion of the 24-hour composite sample. Samples shall be maintained at a temperature of 0-6 degrees Centigrade during collection, shipping, and storage.

4) If Outfall 001 ceases discharging during the collection of the effluent composite sample, the requirements for the minimum number of effluent portions are waived.

However, the permittee must have collected a composite sample volume sufficient for completion of the required test. The abbreviated sample collection, duration, and methodology must be documented in the full report required in Part 3 of this Section.

3. Reporting All reports, tables, plans, summaries, and related correspondence required in any Part of this Section shall be submitted to the attention of the Standards Implementation Team (MC 150) of the Water Quality Division. All DMRs, including DMRs with biomonitoring data, should be sent to the Enforcement Division (MC 224).

a. The permittee shall prepare a full report of the results of all tests conducted pursuant to this permit in accordance with the Report Preparation Section of "Methods for Measuring the Acute Toxicity of Effluents and Receiving Waters to Freshwater and Marine Organisms, Fifth Edition" (EPA-821-R-02-012), or the most recent update thereof, for every valid and invalid toxicity test initiated. All full reports shall be retained for 3 years at the plant site and shall be available for inspection by TCEQ personnel.

b. A full report must be submitted with the first valid biomonitoring test results for each test species and with the first test results any time the permittee subsequently employs a different test laboratory. Full reports need not be submitted for subsequent testing unless specifically requested. The permittee shall routinely report the results of each biomonitoring test on the Table 2 forms provided with this permit. All Table 2 reports must include the information specified in the Table 2 form attached to this permit.

1) Semiannual biomonitoring test results are due on or before January 20th and July 20th for biomonitoring conducted during the previous 6 month period.

2) Quarterly biomonitoring test results are due on or before January 20th, April 20th, July 20th, and October 20th, for biomonitoring conducted during the previous calendar quarter.

c. Enter the following codes on the DMR for the appropriate parameters for valid tests only:

Page 33

STP Nuclear Operating Company TPDES Permit No. WQOOO1908000

1) For the mysid shrimp, Parameter TIE3E, enter a "0" if the mean survival at 24-hours is greater than 50% in the 100% effluent dilution; if the mean survival is less than or equal to 50%, enter a "1."

2) For the inland silverside, Parameter TIE6B, enter a "0" if the mean survival at 24-hours is greater than 50% in the 100% effluent dilution; if the mean survival is less than or equal to 50%, enter a "1.

d. Enter the following codes on the DMR for retests only:

1) For retest number 1, Parameter 22415, enter a "0" if the mean survival at 24-hours is greater than 50% in the 100% effluent dilution; if the mean survival is less than or equal to 50%, enter a "1."

2) For retest number 2, Parameter 22416, enter a "0" if the mean survival at 24-hours is greater than 50% in the 100% effluent dilution; if the mean survival is less than or equal to 50%, enter a "1."

4. Persistent Mortality The requirements of this Part apply when a toxicity test demonstrates significant lethality, here defined as a mean mortality of 50% or greater to organisms exposed to the 100% effluent concentration after 24-hours.

a. The permittee shall conduct 2 additional tests (retests) for each species that demonstrates significant lethality. The two retests shall be conducted once per week for 2 weeks. Five effluent dilution concentrations in addition to an appropriate control shall be used in the retests.

These additional effluent concentrations are 6%, 13%, 25%, 50% and 100% effluent. The first retest shall be conducted within 15 days of the laboratory determination of significant lethality.

All test results shall be submitted within 20 days of test completion of the second retest. Test completion is defined as the 24th hour. The retests shall also be reported on the DMRs as specified in Part 3.d.

b. If one or both of the two retests specified in item 4.a. demonstrates significant lethality, the permittee shall initiate the TRE requirements as specified in Part 5 of this Section.

5. Toxicity Reduction Evaluation

a. Within 45 days of the retest that demonstrates significant lethality, the permittee shall submit a General Outline for initiating a Toxicity Reduction Evaluation (TRE). The outline shall include, but not be limited to, a description of project personnel, a schedule for obtaining consultants (if needed), a discussion of influent and/or effluent data available for review, a sampling and analytical schedule, and a proposed TRE initiation date.

b. Within 90 days of the retest that demonstrates significant lethality, the permittee shall submit a TRE Action Plan and Schedule for conducting a TRE. The plan shall specify the approach and methodology to be used in performing the TRE. A TRE is a step-wise investigation combining toxicity testing with physical and chemical anialysis to determine actions necessary to eliminate or reduce effluent toxicity to a level not effecting significant lethality at the critical dilution.

The TRE Action Plan shall lead to the successful elimination of significant lethality for both test species defined in item L.b. As a minimum, the TRE Action Plan shall include the following:

Page 34

STP Nuclear Operating Company TPDES Permit No. WQOOO 1908000

1) Specific Activities - The TRE Action Plan shall specify the approach the permittee intends to utilize in conducting the TRE, including toxicity characterizations, identifications, confirmations, source evaluations, treatability studies, and/or alternative approaches. When conducting characterization analyses, the permittee shall perform multiple characterizations and follow the procedures specified in the document entitled, "Methods for Aquatic Toxicity Identification Evaluations: Phase I Toxicity Characterization Procedures" (EPA/600/6-91/003), or alternate procedures. The permittee shall perform multiple identifications and follow the methods specified in the documents entitled, "Methods for Aquatic Toxicity Identification Evaluations, Phase HI Toxicity Identification Procedures for Samples Exhibiting Acute and Chronic Toxicity" (EPA/600/R-92/080) and "Methods for Aquatic Toxicity Identification Evaluations, Phase III Toxicity Confirmation Procedures for Samples Exhibiting Acute and Chronic Toxicity" (EPA/600/R-92/081). All characterization, identification, and confirmation tests shall be conducted in an orderly and logical progression;

2) Sampling Plan - The TRE Action Plan should describe sampling locations, methods, holding times, chain of custody, and preservation techniques. The effluent sample volume collected for all tests shall be adequate to perform the toxicity characterization/

identification/ confirmation procedures, and chemical-specific analyses when the toxicity tests show significant lethality. Where the permittee has identified or suspects specific pollutant(s) and/or source(s) of effluent toxicity, the permittee shall conduct, concurrent with toxicity testing, chemical-specific analyses for the identified and/or suspected pollutant(s) and/or source(s) of effluent toxicity;

3) Quality Assurance Plan - The TRE Action Plan should address record keeping and data evaluation, calibration and standardization, baseline tests, system blanks, controls, duplicates, spikes, toxicity persistence in the samples, randomization, reference toxicant control charts, as well as mechanisms to detect artifactual toxicity; and

4) Project Organization - The TRE Action Plan should describe the project staff, project manager, consulting engineering services (where applicable), consulting analytical and toxicological services, etc.

c. Within 30 days of submittal of the TRE Action Plan and Schedule, the permittee shall implement the TRE with due diligence.

d. The permittee shall submit quarterly TRE Activities Reports concerning the progress of the TRE. The quarterly TRE Activities Reports are due on or before April 20th, July 20th, October 20th, and January 20th. The report shall detail information regarding the TRE activities including:

1) results and interpretation of any chemical-specific analyses for the identified and/or suspected pollutant(s) performed during the quarter;

2) results and interpretation of any characterization, identification, and confirmation tests performed during the quarter;

3) any data and/or substantiating documentation which identifies the pollutant(s) and/or source(s) of effluent toxicity;

4) results of any studies/evaluations concerning the treatability of the facility's effluent toxicity; Page 35

STP Nuclear Operating Company TPDES Permit No. WQO0O 1908000

5) any data which identifies effluent toxicity control mechanisms that will reduce effluent toxicity to the level necessary to eliminate significant lethality; and

6) any changes to the initial THE Plan and Schedule that are believed necessary as a result of the TRE findings.

Copies of the TRE Activities Report shall also be submitted to the U.S. EPA Region 6 office.

e. During the TRE, the permittee shall perform, at a minimum, quarterly testing using the more sensitive species; testing for the less sensitive species shall continue at the frequency specified in Part L.b.

f. If the effluent ceases to effect significant lethality (herein as defined below) the permittee may end the TRE. A "cessation of lethality" is defined as no significant lethality for a period of 12 consecutive weeks with at least weekly testing. At the end of the 12 weeks, the permittee shall submit a statement of intent to cease the TRE and may then resume the testing frequency specified in Part 1.b. The permittee may only apply the "cessation of lethality" provision once.

This provision accommodates situations where operational errors and upsets, spills, or sampling errors triggered the TRE, in contrast to a situation where a single toxicant or group of toxicants cause lethality. This provision does not apply as a result of corrective actions taken by the permittee. "Corrective actions" are herein defined as proactive efforts which eliminate or reduce effluent toxicity. These include, but are not limited to, source reduction or elimination, improved housekeeping, changes in chemical usage, and modifications of influent streams and/or effluent treatment.

The permittee may only apply this cessation of lethality provision once. If the effluent again demonstrates significant lethality to the same species, the permit will be amended to add a WET limit with a compliance period, if appropriate. However, prior to the effective date of the WET limit, the permittee may apply for a permit amendment removing and replacing the WET limit with an alternate toxicity control measure by identifying and confirming the toxicant and/or an appropriate control measure.

g. The permittee shall complete the TRE and submit a Final Report on the THE Activities no later than 18 months from the last test day of the retest that demonstrates significant lethality. The permittee may petition the Executive Director (in writing) for an extension of the 18-month limit. However, to warrant an extension the permittee must have demonstrated due diligence in their pursuit of the TIE/TRE and must prove that circumstances beyond their control stalled the TIE/TIRE. The report shall specify the control mechanism(s) that will, when implemented, reduce effluent toxicity as specified in item 5.g. The report will also specify a corrective action schedule for implementing the selected control mechanism(s). A copy of the THE Final Report shall also be submitted to the U.S. EPA Region 6 office.

h. Within 3 years of the last day of the test confirming toxicity, the permittee shall comply with 307.6.(e)(2)(B), which requires greater than 50% survival of the test organism in 100% effluent at the end of 24-hours. The permittee may petition the Executive Director (in writing) for an extension of the 3-year limit. However, to warrant an extension the permittee must have demonstrated due diligence in their pursuit of the TIE/TRE and must prove that circumstances beyond their control stalled the TIE/TRE.

Page 36

STP Nuclear Operating Company TPDES Permit No. WQ0001908000 The requirement to comply with 307.6.(e)(2)(B) may be exempted upon proof that toxicity is caused by an excess, imbalance, or deficiency of dissolved salts. This exemption excludes instances where individually toxic components (e.g. metals) form a salt compound. Following the exemption, the permit may be amended to include an ion-adjustment protocol, alternate species testing, or single species testing.

Based upon the results of the TRE and proposed corrective actions, this permit may be amended to modify the biomonitoring requirements where necessary, to require a compliance schedule for implementation of corrective actions, to specify a WET limit, to specify a BMP, and/or to specify a CS limit.

Page 37

STP Nuclear Operating Company TPDES Permit No. WQ0001908000 TABLE 2 (SHEET 1 OF 2)

MYSID SHRIMP SURVIVAL GENERAL INFORMATION PERCENT SURVIVAL j i e~R pPerce~nt

_j~IE

-e~ffluent()- .7:-

IE

-24h c_ IJ LI E-II _____ IIIIIlIIIIIIIZII7 _____

WWW--

Enter percent effluent corresponding to the LC50 below:

24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months LC50 = % effluent Page 38

STP Nuclear Operating Company TPDES Permit No. WQOOO1908000 TABLE 2 (SHEET 2 OF 2)

INLAND SILVERSIDE SURVIVAL GENERAL INFORMATION (mp)Date.-

Tim J]lCoposite 8amp~jld C-ollected *:;**%i~*!;i*:~**;i~'*-

7: 1 'i!**

I Tst: Iiitatd- I PERCENT SURVIVAL

.. - Percent~effluent(/o N

.im Rep...

........... 13%-2 % 0 % I I~WIF Enter percent effluent corresponding to the LC50 below:

24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months LC50 = %effluent Page 39

v t e Letter Sequence Request
TAC:ME4938, (Approved, Closed)
Initiation Request, Request, Request, Request, Request, Request, Request, Request, Request, Request, Request Acceptance Administration Meeting Questions 6 July 2011 4 August 2011 18 August 2011 18 August 2011 1 September 2011 28 September 2011 29 February 2012 14 February 2012 29 February 2012 25 June 2012 Answers 22 September 2011 18 October 2011 5 July 2011 5 July 2011 23 August 2011 6 September 2011 12 September 2011 17 November 2011 19 January 2012 16 February 2012 12 March 2012 6 March 2013 Results Approval, Approval, Approval, Approval Other: ML110872079, ML11145A064, ML11256A057, ML11256A058, ML12086A081, ML12264A642, ML13029A497, ML13063A071, ML13198A056, ML13253A163, ML16118A311, NOC-AE-12002780, Clarification of Information in Support of the Review of the License Renewal Application, NOC-AE-13002945, Update to License Renewal Application - Environmental Permits
MONTHYEAR2012-11-30 [Table View]

NOC-AE-12002840, Renewal of the Wastewater Discharge Permit

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